CN110997324A - Method for producing laminate - Google Patents

Abstract

Provided is a method for producing a laminate which comprises an adherend and a pressure-sensitive adhesive sheet that covers a part of the adherend and has a pressure-sensitive adhesive strength to the adherend of 5N/25mm or more. The method for manufacturing the laminated body sequentially comprises the following steps: a sticking step of sticking an adhesive sheet to the adherend; a dicing step of performing cutting processing at a boundary between a first region of the adhesive sheet and a second region of the adhesive sheet; and a partial removal step of leaving the first region on the adherend and peeling and removing the second region from the adherend. Here, the adhesive layer includes: the partial removal step is performed before the adhesive force of the adhesive sheet to the adherend exceeds 2N/25 mm.

Description

Method for producing laminate

Technical Field

The present invention relates to a method for producing a laminate.

The present application claims priority based on japanese laid-open application 2017-253311, applied at 28.12.2017, and japanese laid-open application 2018-228925, applied at 6.12.2018, both of which are incorporated herein by reference in their entirety.

Background

When a laminate is used in which an adherend is partially covered with one or more pressure-sensitive adhesive sheets by attaching the pressure-sensitive adhesive sheet to the adherend, various patterns can be expressed according to the shape and arrangement of the pressure-sensitive adhesive. As a method for producing a laminate in which an adherend is partially covered with a pressure-sensitive adhesive sheet as described above with high accuracy, the following method is generally used: for example, a method of cutting an adhesive sheet into a desired shape of an adhesive sheet in advance, and then aligning and attaching the adhesive sheet to an adherend, such as attaching a cover film of a circuit board. As a related art document of such a technique, patent document 1 can be cited.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open application publication No. 2013-38379

Disclosure of Invention

Problems to be solved by the invention

However, in the above method, the pressure-sensitive adhesive sheet is cut into a desired shape of the pressure-sensitive adhesive sheet in advance, and then aligned and bonded to a predetermined adherend site, and therefore, both errors of the cutting accuracy and the bonding accuracy occur. Therefore, in the future production of miniaturized and highly refined electronic components, very expensive equipment may be required to produce products with high yield. Further, for example, when the size of the pressure-sensitive adhesive sheet to be cut is large, when the shape is complicated, or the like, it is more difficult to attach the pressure-sensitive adhesive sheet to an adherend with good positional accuracy and shape accuracy. In particular, when a strongly adhesive pressure-sensitive adhesive sheet is used for producing a highly durable laminate, the operation of accurately bonding the pressure-sensitive adhesive sheet to an adherend tends to be difficult.

Accordingly, an object of the present invention is to provide a method for efficiently producing a laminate in which a pattern obtained from a pressure-sensitive adhesive sheet is accurately formed on an adherend and the pressure-sensitive adhesive sheet is firmly bonded to the adherend. Other related inventions provide apparatus suitable for implementing the manufacturing method.

Means for solving the problems

According to the present specification, there is provided a method for producing a laminate comprising an adherend and a pressure-sensitive adhesive sheet covering a part of the adherend, wherein the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive strength to the adherend of 5N/25mm or more. The method for manufacturing the laminated body sequentially comprises the following steps: a bonding step of bonding a pressure-sensitive adhesive sheet including a base material layer and a pressure-sensitive adhesive layer laminated on at least the adherend-side surface of the base material layer to the adherend; a dicing step of performing cutting processing at a boundary between a first region of the adhesive sheet and a second region of the adhesive sheet; and a partial removal step of leaving the first region on the adherend and peeling and removing the second region from the adherend. Here, the partial removal step is performed before the adhesive strength of the adhesive sheet to the adherend exceeds 2N/25 mm.

According to the manufacturing method, by sequentially performing the attaching step, the cutting step, and the partial removal step, it is possible to efficiently obtain a configuration in which the first region is arranged on the adherend with good shape accuracy and positional accuracy. Further, since the partial removal step is performed before the adhesive strength of the adhesive sheet to the adherend exceeds 2N/25mm, the operation of peeling the second region from the adherend is facilitated, and deformation and damage of the adherend are also less likely to occur.

In some embodiments, the adhesive sheet may preferably have an adhesive force of 2N/25mm or less after 24 hours at 23 ℃ after being attached to polyimide. Such a pressure-sensitive adhesive sheet can flexibly cope with a production cycle (lead time) of the production process of the laminate.

In some aspects of the laminate manufacturing method disclosed herein, the heating treatment is performed after the partial removal step so that the adhesive force of the first region to the adherend is 5N/25mm or more. This embodiment can be implemented using, for example, an adhesive sheet provided with an adhesive layer containing: the polymer a having a glass transition temperature of less than 0 ℃ and the polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer, but the polymer a and the polymer B are not limited thereto.

In some embodiments, the monomer component constituting the polymer a may include an N-vinyl cyclic amide. The pressure-sensitive adhesive sheet using the polymer a having the composition containing the N-vinyl cyclic amide as the constituent monomer component can exhibit good adhesion force-increasing properties, and therefore can be preferably used for the implementation of the production method disclosed herein.

According to the present specification, there is provided a method for producing a laminate including an adherend and a pressure-sensitive adhesive sheet covering a part of the adherend, the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive strength to the adherend of 5N/25mm or more, the method comprising the steps of:

a bonding step of bonding a pressure-sensitive adhesive sheet including a base material layer and a pressure-sensitive adhesive layer laminated on at least the adherend-side surface of the base material layer to the adherend;

a dicing step of performing cutting processing at a boundary between a first region of the adhesive sheet and a second region of the adhesive sheet; and

a partial removal step of leaving the first region on the adherend and peeling and removing the second region from the adherend,

here, the adhesive layer includes: a polymer A having a glass transition temperature of less than 0 ℃ and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer, wherein the monomer component constituting the polymer A contains an N-vinyl cyclic amide,

the partial removal step is performed before the adhesive strength of the adhesive sheet to the adherend exceeds 2N/25mm,

and performing a heat treatment after the partial removal step so that the adhesive force of the first region to the adherend is 5N/25mm or more. This method enables efficient production of a laminate having a pattern formed from the pressure-sensitive adhesive sheet on an adherend with high accuracy.

In some embodiments, the monomer component constituting the polymer a may further contain a hydroxyl group-containing monomer in addition to the N-vinyl cyclic amide. The production method disclosed herein can be suitably carried out using an adhesive sheet using the polymer a having a composition in which the N-vinyl cyclic amide and the hydroxyl group-containing monomer are combined as constituent monomer components as described above.

In some other aspects of the method for producing a laminate disclosed herein, the first region is subjected to ultraviolet irradiation treatment after the partial removal step so that the adhesive force to the adherend of the first region is 5N/25mm or more. This embodiment can be implemented using, for example, an adhesive sheet including an adhesive layer formed of a photocurable composition including a base polymer and a photocurable agent, the photocurable agent being a polyfunctional (meth) acrylate, and the content of the photocurable agent being 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the base polymer, but is not limited thereto.

The method for manufacturing a laminate disclosed herein may be implemented as follows: after the partial removal step, the film is stored at normal temperature until the adhesive strength of the first region to the adherend is 5N/25mm or more.

In the present specification, the normal temperature means a temperature of about 0 to 35 ℃, typically 10 to 35 ℃ unless otherwise specified.

In some embodiments, the pressure-sensitive adhesive sheet may preferably have a thickness of 30 μm or more and a thickness Ts of the base layer of 2 times or more the thickness Ta of the pressure-sensitive adhesive layer. By using such an adhesive sheet, there is an advantage that the operation of attaching to the adherend and the operation of detaching from the second region can be easily performed.

Preferably, the second region is set so that at least one end thereof reaches an end of the adhesive sheet. This provides an advantage that the second region can be easily picked up when the partial removal step is performed. From the viewpoint of improving the pickup property, the second region may have a shape in which one end reaching the end of the adhesive sheet is widened toward the end of the adhesive sheet.

The manufacturing method disclosed herein may preferably be such that the used area in the pasting step is 2500cm²The above-described embodiment of the pressure-sensitive adhesive sheet having a short side length of 50cm or more is preferably carried out. In the case of using a wide adhesive sheet having a large area, the advantages obtained by the manufacturing method disclosed herein can be more effectively utilized.

The production method disclosed herein may use, as the pressure-sensitive adhesive sheet and the adherend used in the affixing step, a pressure-sensitive adhesive sheet and an adherend each including a plurality of cells corresponding to the laminate, and may further include, as a step performed after the affixing step, a dividing step of dividing the pressure-sensitive adhesive sheet and the adherend into the cells. By thus attaching the pressure-sensitive adhesive sheet including the plurality of cells to an adherend and then dividing the sheet, a plurality of laminated bodies can be efficiently manufactured. The plurality of units may have the same or different configurations.

According to the present specification, an apparatus for producing a laminate including an adherend and a pressure-sensitive adhesive sheet laminated on a part of the adherend can be provided. The apparatus includes an adhering mechanism for adhering an adhesive sheet. The apparatus may further include a cutting mechanism configured to cut the adhesive sheet. Further, the apparatus may include a peeling mechanism for peeling the second region. Any of the laminate manufacturing methods disclosed herein can be suitably implemented using a manufacturing apparatus having such a configuration.

It should be noted that the claims to be claimed in the present application also include an embodiment in which the above-described elements are appropriately combined.

Drawings

Fig. 1 is a flowchart illustrating a method for manufacturing a laminate according to an embodiment.

Fig. 2 is a perspective view showing a laminate manufactured by the laminate manufacturing method according to one embodiment.

Fig. 3 is a sectional view taken along line III-III of fig. 2.

Fig. 4 is a perspective view illustrating a dicing step in the laminate manufacturing method according to the embodiment.

Fig. 5 is an explanatory view showing a schematic configuration of a laminate manufacturing apparatus used in the laminate manufacturing method according to the embodiment.

FIG. 6 is an explanatory view showing a method of carrying out the durability test.

Detailed Description

Suitable embodiments of the present invention are described below. It is to be noted that matters necessary for carrying out the present invention other than the matters specifically mentioned in the present specification can be understood by those skilled in the art based on the teaching of the implementation of the invention described in the present specification and the common general knowledge at the time of application. The present invention can be implemented based on the contents disclosed in the present specification and the common general knowledge in the art.

In the following drawings, members and portions that perform the same function are sometimes denoted by the same reference numerals, and redundant description may be omitted or simplified. The embodiments shown in the drawings are schematic for the purpose of clearly illustrating the present invention, and do not necessarily show actual dimensions or scales accurately.

Method for producing laminate

Fig. 1 is a flowchart illustrating a method for manufacturing a laminate according to an embodiment, fig. 2 is a perspective view illustrating a laminate manufactured by the method, and fig. 3 is a sectional view taken along line III-III thereof. As shown in fig. 2 and 3, the laminate 1 produced according to this embodiment includes: an adherend 10, and pressure- sensitive adhesive sheets 21A, 21B covering a part of the surface 10A of the adherend 10. After the pressure- sensitive adhesive sheets 21A and 21B are attached to the adherend 10, the pressure- sensitive adhesive sheets 21A and 21B are formed from the first region 21 remaining on the adherend 10 by leaving the first region 21 of the pressure-sensitive adhesive sheet 20 on the adherend 10 and peeling off and removing the second region 22 from the adherend 10. The pressure-sensitive adhesive sheet 20 has a structure in which a pressure-sensitive adhesive layer 204 is laminated on one surface of a base material layer 202.

As shown in fig. 1, the method for manufacturing a laminate according to this embodiment includes the steps of: a bonding step S10, a dicing step S20, and a partial removal step S30.

In the joining step S10, the pressure-sensitive adhesive sheet 20 is joined to the adherend 10. The adhesive sheet 20 used in this step includes: a first region 21 included in the components of the laminate 1 in the form of the adhesive sheets 21A and 21B; the second region 22 is not a component of the laminate 1, and is used only in the process of manufacturing the laminate 1. In the example shown in fig. 2, a second region 22 extending linearly from one end to the other end in the longitudinal direction of the adhesive sheet 20 is set at substantially the center of the width of the adhesive sheet 20. The adhesive sheet 20 used in the pasting step S10 has the first region 21 and the second region 22 physically connected to each other, and these regions 21 and 22 can be handled as a continuous adhesive sheet 20.

In the cutting step S20, cutting processing is performed at the boundary between the first region 21 and the second region 22 of the pressure-sensitive adhesive sheet 20 attached to the adherend 10. For example, as shown in fig. 4, laser cutting is performed by irradiating a laser beam L along a line C to cut which forms a boundary between the first region 21 and the second region 22. Although fig. 4 shows an example of laser cutting, the means for cutting is not particularly limited, and may be appropriately selected from various known cutting means according to the purpose and application. Examples of such cutting means include: using CO₂Laser cutting with a laser such as a laser beam or a YAG laser; cutting with Thomson knife, top knife, rotary knife, and small knife; cutting off the blade; and the like, but not limited thereto. The cutting means may be used singly or in combination of two or more.

The partial removal step S30 is performed before the adhesive sheet adhered to the adherend in the adhering step has an adhesive force to the adherend exceeding 2N/25mm (in other words, while the adhesive force is suppressed to 2N/25mm or less after the adhering). In the partial removal step S30, the second region 22 is peeled and removed from the adherend 10 while leaving the first region 21 on the adherend 10. For example, the second region 22 is peeled off from one end of the longitudinal direction of the adhesive sheet 20 toward the other end. As a result, as shown in fig. 2 and 3, the pressure- sensitive adhesive sheets 21A and 21B formed in the first region 21 are arranged on the adherend 10 with a space therebetween, and the adherend 10 is exposed between these pressure- sensitive adhesive sheets 21A and 21B.

In the method for producing a laminate of this embodiment, after the pressure-sensitive adhesive sheet 20 is adhered to the adherend 10, the second region 22, which is a part of the pressure-sensitive adhesive sheet 20, is peeled and removed from the adherend 10, whereby a coating pattern formed of two pressure- sensitive adhesive sheets 21A and 21B arranged to be spaced apart from each other is formed on the adherend 10. According to this method, the first region 21 constituting the two pressure- sensitive adhesive sheets 21A and 21B spaced apart from each other can be bonded to the adherend 10 in the form of one pressure-sensitive adhesive sheet 20 in the laminate 1, and at the time of bonding the pressure-sensitive adhesive sheet 20, it is not necessary to adjust the relative positional relationship between the pressure-sensitive adhesive sheet 21A and the pressure-sensitive adhesive sheet 21B, and the production efficiency of the laminate 1 is improved. Further, since the cutting process is performed on the boundary between the first region 21 and the second region 22 of the pressure-sensitive adhesive sheet 20 after the pressure-sensitive adhesive sheet 20 is attached to the adherend 10, the shape accuracy of the first region 21 and the positional accuracy with respect to the adherend 10 are easily improved. For example, when the adhesive sheet 20 is slightly displaced from the position to which the adherend 10 is attached in the attaching step S10, or when the adhesive sheet 20 is slightly expanded or deformed due to a temperature change, release of internal stress, or the like, the influence of these can be eliminated or reduced by adjusting the position or shape of the cutting process in the cutting step S20.

In the above-described production method, a laminate 1 is produced in which the adhesive strength of the adhesive sheets 21A and 21B to an adherend is 5N/25mm or more. Such a strong bonding of the pressure- sensitive adhesive sheets 21A, 21B to the adherend 10 is preferable from the following viewpoints: when the laminate 1 is used, the pressure- sensitive adhesive sheets 21A and 21B are prevented from peeling or floating from the adherend 10 due to external force such as contact with a human hand, deformation of the adherend, exposure of the laminate to environmental factors such as weather or temperature change, and the like. On the other hand, in the partial removal step S30, when the adhesiveness of the second region 22 to the adherend 10 is too high, the following disadvantages may occur: when the second region 22 is peeled off, the adherend 10 is deformed such as stretched, and the surface is peeled off, or the second region 22 is broken during the peeling. By performing the partial removal step S30 before the pressure-sensitive adhesive sheet adhered to the adherend in the adhering step S10 has an adhesive strength to the adherend of more than 2N/25mm by the above-described manufacturing method, the laminate 1 in which the pressure- sensitive adhesive sheets 21A and 21B are firmly adhered to the adherend 10 can be manufactured, and the above-described problem in the partial removal step S20 can be avoided or reduced.

In some embodiments, the adhesive force a of the adhesive sheet to the adherend in the partial removal step is from the viewpoint of ease of peeling of the second region_PFor example, less than 2N/25mm, or less than 1.5N/25mm,The thickness may be 1.3N/25mm or less, 1N/25mm or less, or 0.8N/25mm or less. Adhesive force A_PThe lower limit of (b) is not particularly limited, and from the viewpoint of suppressing the positional shift and floating of the first region in the dicing step and the partial removal step, it may be, for example, 0.005N/25mm or more, and may be 0.01N/25mm or more, 0.05N/25mm or more, and may be 0.1N/25mm or more, and 0.2N/25mm or more.

The production method disclosed herein can be preferably carried out using an adhesive sheet having an adhesive strength after 24 hours at 23 ℃ (hereinafter also referred to as adhesive strength after 24 hours at room temperature) of 2N/25mm or less after being bonded to polyimide. Such an adhesive sheet can flexibly cope with the production cycle of the production process of the laminate. The upper limit of the adhesive force after 24 hours at room temperature can be, for example, the adhesive force A exemplified above_PTo the same extent. The lower limit of the adhesive force after 24 hours at room temperature can be, for example, the adhesive force A exemplified above_PAny lower limit of (c) is to the same extent.

After the partial removal step S30 is performed, if necessary, a pressure-sensitive adhesive strength increasing step S40 may be performed to further increase the pressure-sensitive adhesive strength of the pressure- sensitive adhesive sheets 21A and 21B to the adherend 10. By the production method including the adhesive strength increasing step, the period until the desired laminate (that is, the laminate in which the adhesive strength of the adhesive sheet to the adherend is 5N/25mm or more) is obtained can be shortened. This can improve the productivity of the laminate. Further, by performing the adhesive strength increasing step, a laminate having a higher adhesive strength of the adhesive sheet to an adherend tends to be produced.

The adhesive strength increasing step S40 may be a step of applying a stimulus for promoting the increase in adhesive strength of the adhesive sheets 21A and 21B. The content of the above-mentioned stimulus can be appropriately selected depending on the type of the adhesive sheet used and the like. Examples of the above stimulus may include heating, irradiation of active light, pressing (pressurization), and the like. These stimuli may be used singly or in combination of two or more.

In the method for producing a laminate disclosed herein, the step of increasing the adhesive strength is not essential, and is an arbitrary step that can be suitably employed in consideration of the type of the adhesive sheet to be used, the desired productivity and performance of the laminate, the production facility and production cost of the laminate, and the like. For example, by appropriately selecting the pressure-sensitive adhesive sheet used for the production of the laminate, even in a mode in which no particular pressure-sensitive adhesive strength increasing step is performed after the partial removal step, the partial removal step can be performed before the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive strength to an adherend of more than 2N/25mm, and a laminate in which the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive strength to the adherend of 5N/25mm or more can be produced.

The pressure-sensitive adhesive sheet contained in the laminate produced by the method disclosed herein includes a base material layer and a pressure-sensitive adhesive layer, and is bonded to an adherend via the pressure-sensitive adhesive layer. In the case where the pressure-sensitive adhesive sheet and the adherend are joined together with the pressure-sensitive adhesive in the laminate obtained in this way, that is, the pressure-sensitive adhesive maintains a desired viscoelasticity, it is preferable from the viewpoint of flexibility, impact resistance, stress relaxation properties, low-temperature characteristics, adhesion between the adherend and the pressure-sensitive adhesive sheet, and the like of the laminate produced by the method disclosed herein.

In the example shown in fig. 2, the pressure-sensitive adhesive sheet 20 having substantially the same size as the adherend 10 is attached so as to cover the entire surface (entire area) on one side of the adherend 10, but the manner of attaching the pressure-sensitive adhesive sheet to the adherend 10 is not limited thereto. For example, the pressure-sensitive adhesive sheet may be attached so as to cover only a part of the area on one side of the adherend, or may be attached so that a part of the pressure-sensitive adhesive sheet protrudes from the adherend. In the adhesive sheet used in the pasting step S10, the first region and the second region may be connected to each other to such an extent that the two regions can be handled as a continuous sheet, and a cutting support structure such as a slit (a perforated line or the like) or a half cut may be provided at the boundary between the first region and the second region within this range. Here, the half-cut means a cut having a depth not penetrating through the adhesive sheet in the thickness direction, and typically forms a cut having a depth not penetrating through the base material layer in the thickness direction. Such a cut can be formed, for example, by a processing blade that penetrates from the back surface of the base material layer (the side opposite to the side on which the adhesive layer is laminated) to a depth that does not penetrate the base material layer. In one embodiment, from the viewpoint of improving the handleability of the adhesive sheet, reducing the manufacturing cost, and the like, it is preferable to use an adhesive sheet in which a cutting support structure is not provided at the boundary between the first region and the second region. The pressure-sensitive adhesive sheet used in the joining step S10 may be provided with a mark that assists in the alignment between the pressure-sensitive adhesive sheet and the adherend. The mark may be a structural mark such as a through hole, a notch, a pit, or the like, a visual mark based on an optically detectable mark (e.g., printing, coloring), or the like, or a mark based on the arrangement of different members (e.g., an identification label is attached, and an element capable of transmitting or reflecting a signal is fixed). Such a mark may be provided in one or both of the first region and the second region, or may be provided at a boundary between the first region and the second region.

In the example shown in fig. 4, in the cutting step S20, continuous linear cutting is performed to a depth that penetrates the pressure-sensitive adhesive sheet and reaches the surface of the adherend, but the form of the cutting is not limited to this. For example, the first region and the second region after the dicing step S20 may be partially connected to each other within a range where the partial removal step S30 can be appropriately performed. Examples of such cutting processing include: a discontinuous cutting process such as a perforated line, a half-cut process, a process combining a perforated line and a half-cut process (for example, a cutting process in which a slit penetrating the base material layer and a cut having a depth not penetrating the base material layer are alternately repeated), and the like. The cutting process may be performed to a depth that penetrates the pressure-sensitive adhesive sheet and reaches the surface of the adherend, may be performed to a depth that penetrates the pressure-sensitive adhesive sheet and reaches a partial depth from the surface of the adherend, or may be performed to a depth that does not penetrate the pressure-sensitive adhesive sheet (i.e., half-cut). In the production method disclosed here, since the adhesive strength of the adhesive sheet to the adherend is suppressed to be low when the partial removal step S30 is performed, it is preferable to perform the cutting process so that the first region and the second region are completely separated from each other until the cutting process reaches at least the depth of penetration of the base material layer. This is advantageous from the viewpoints of improvement in the pickup property of the second region, prevention of floating and/or displacement of the first region, improvement in the outer shape accuracy of the first region, and the like in the partial removal step S30.

In the example shown in fig. 4, one end and the other end of the second region extending linearly reach the end of the adhesive sheet. Setting the second region such that at least one end of the second region reaches the end of the adhesive sheet in this way is preferable from the viewpoint of the pickup property of the second region in the partial removal step S30. In the case where the second region does not reach the end of the adhesive sheet, for example, the second region can be picked up by sticking a highly adhesive tape to the back surface of the second region at one end of the second region and lifting the adhesive tape. This pickup method may also be employed in a manner that at least one end of the second region reaches the end of the adhesive sheet. In the method for producing a laminate disclosed herein, when the adhesive force of the adhesive sheet to the adherend in the partial removal step is 2N/25mm or less, it is advantageous from the viewpoint of improving the pickup property of the second region by the method of attaching the adhesive tape and lifting it out as described above.

In the aspect of setting the second region to reach the end of the adhesive sheet, the width of the second region to reach the end of the adhesive sheet is preferably 0.2mm or more, may be 0.5mm or more, and may be 1mm or more from the viewpoint of the pickup property. In order to improve the pickup property, the following structure may be adopted: the width of the second region becomes wider as it reaches the vicinity of the end of the adhesive sheet. In addition, from the viewpoint of downsizing of a product (electronic device or the like) including the laminate obtained by the manufacturing method disclosed herein, the width of the second region reaching the end portion of the adhesive sheet is preferably 10mm or less, and more preferably 8mm or less.

When the laminate production method disclosed herein includes the adhesive strength increasing step, the degree of increase in adhesive strength in the step is not particularly limited, and the adhesive strength after the step or the adhesive strength of the laminate obtained through the step may be relatively higher than the adhesive strength before the step. In some embodiments, the adhesive strength increasing step is preferably performed in such a manner that the adhesive strength a to the adherend before the step₀[N/25mm]And adhesive strength A to an adherend after the step₁[N/25mm]Satisfy the relationship of (A)₁/A₀) Is carried out in a mode of more than or equal to 2. I.e. increased adhesionIn the high step, the adhesive strength of the adhesive sheet to the adherend is preferably increased by 2 times or more before the high step. Such a step of increasing the adhesive strength tends to be suitable for achieving both the ease of removal of the second region in the partial removal step and the strong adhesiveness of the pressure-sensitive adhesive sheet to an adherend in the laminate to be produced. In some embodiments, the ratio (A) is₁/A₀) For example, the number may be 3 or more, 5 or more, or 10 or more. The above ratio (A)₁/A₀) The upper limit of (b) is not particularly limited, but is preferably 10000 or less, 5000 or less, or 2000 or less in general from the viewpoint of suppressing the positional shift and floating of the first region before the adhesive force increasing step. The above adhesive force A₀、A₁Each of the values can be determined by measuring the peel strength of the pressure-sensitive adhesive sheet from an adherend under conditions of a peel angle of 180 degrees and a tensile rate of 300 mm/min at 23 ℃ and 50% RH based on JIS Z0237.

Adhesive force A of adhesive sheet to adherend before adhesive force increasing step₀For example, the adhesive strength A in the partial removal step_PTo approximately the same extent. Thus, the above exemplified adhesive force A_PThe upper limit values and the lower limit values of (A) may be independently applied to the adhesive force A₀The respective upper and lower limits can be employed. Further, the above exemplified adhesive force A_PThe upper limit and the lower limit of (B) may be independently applied to the initial adhesive force (B) described later₀The respective upper and lower limits can be employed.

Adhesive force A of adhesive sheet to adherend in laminate produced by the method disclosed herein_FFor example, it may exceed 5N/25mm, may be 7N/25mm or more, may be 10N/25mm or more, or may be 12N/25mm or more. Adhesive force A_FThe pressure-sensitive adhesive sheet is preferably high in view of suppressing peeling and lifting of the pressure-sensitive adhesive sheet from an adherend when the laminate is used. Adhesive force A_FThe upper limit of (b) is not particularly limited. In some embodiments, the adhesive force a is a force that can easily achieve the peeling easiness of the second region in the partial removal step_FFor example, the thickness may be 50N/25mm or less, 40N/25mm or less, or 35N/25mm or lessLower, 30N/25mm below.

In the embodiment including the adhesive strength increasing step, the adhesive strength a of the adhesive sheet to the adherend after the adhesive strength increasing step₁[N/25mm]For example, the adhesive strength A of the adhesive sheet to an adherend in the laminate to be produced_FTo approximately the same extent. Thus, the above exemplified adhesive force A_FThe upper limit values and the lower limit values of (A) can be independently applied to the adhesive force A₁The respective upper and lower limits can be employed. Further, the above exemplified adhesive force A_FThe upper limit and the lower limit of (B) may be independently applied to the after-stimulus adhesive force B described later₁The respective upper and lower limits can be employed.

The content of the stimulus given to the adhesive sheet in the adhesive force increasing step may be set so that, for example, the initial adhesive force B of the adhesive sheet to be used to polyimide₀Relative to post-stimulus adhesive force B₁Ratio (B) defines the adhesion force increase ratio₁/B₀) Satisfying a prescribed target value. Initial adhesion B₀And post-stimulus adhesive force B₁The measurement was carried out by the method described in the examples below.

When the production method disclosed herein includes the adhesive force increasing step, the adhesive force increasing step is preferably performed at an adhesive force increasing ratio (B)₁/B₀) For example, 2 or more, more preferably the adhesive force increasing ratio (B)₁/B₀) Is carried out in a manner of 3 or more, 5 or more, 10 or more, or 15 or more. In addition, the adhesive strength increasing step may be performed at an adhesive strength increasing ratio (B) from the viewpoint of reducing the load applied to the pressure-sensitive adhesive sheet and the adherend and improving the productivity of the laminate₁/B₀) About 10000 or less, 5000 or less, or 2000 or less. In several embodiments, the adhesion force increase ratio (B)₁/B₀) For example, the average particle size may be 1000 or less, 500 or less, 200 or less, and 100 or less.

In addition, in a flexible display panel, a flexible printed wiring board (FPC), a device in which a display panel and a wiring board are integrated, or the like, a flexible substrate material is used, and heat resistance is improvedFrom the viewpoint of dimensional stability, a polyimide film is often used as the substrate material. Exhibits the above adhesion B to polyimide₀、B₁Or the adhesion force increasing ratio (B)₁/B₀) The pressure-sensitive adhesive sheet of (3) is used for the production of a laminate in a mode in which polyimide is used as an adherend, has good workability in peeling the second region in the partial removal step, and exhibits excellent reliability in adhesion to the adherend when the resulting laminate is used. By utilizing this property, a thin film cover layer of an FPC can be formed accurately and efficiently. Therefore, the method disclosed herein can be preferably used for manufacturing an FPC provided with a thin film cover layer, for example.

In the adhesive strength increasing step, the heating temperature when heating as a stimulus to be given to the adhesive sheet is not particularly limited, and may be set in consideration of workability, economy, heat resistance of a base material layer and an adherend which can be contained in the adhesive sheet, and the like. The heating temperature may be, for example, less than 150 ℃ or not more than 120 ℃, or not more than 100 ℃, not more than 80 ℃ or not more than 70 ℃. The heating temperature may be, for example, 40 ℃ or higher, 50 ℃ or higher, or 60 ℃ or higher, or 80 ℃ or higher, or 100 ℃ or higher. With a higher heating temperature, the adhesive force can be increased by a shorter time of treatment. The heating time is not particularly limited, and may be, for example, 1 hour or less, 30 minutes or less, 10 minutes or less, or 5 minutes or less. Alternatively, the heat treatment may be performed for a longer period of time (for example, 2 hours or more, 5 hours or more, or the like) within a range in which the pressure-sensitive adhesive sheet or the adherend is not significantly thermally deteriorated. The heating treatment may be performed once or in a plurality of times.

The pressure-sensitive adhesive sheet used in the sticking step may include only one region (first region) to be a pressure-sensitive adhesive sheet constituting the laminate in one pressure-sensitive adhesive sheet, may include two first regions spaced apart from each other as shown in fig. 2, or may include three or more first regions. When one adhesive sheet contains a plurality of first regions, the shapes of the first regions may be the same or different. Similarly, the adhesive sheet used in the sticking step may include only one second region peeled and removed in the partial removal step in one adhesive sheet as shown in fig. 4, for example, or may include two or more, or three or more. When one adhesive sheet contains a plurality of second regions, the shapes of the second regions may be the same or different.

In the laminate production methods of the several aspects, as the pressure-sensitive adhesive sheet and the adherend used in the joining step, a pressure-sensitive adhesive sheet and an adherend including a plurality of cells corresponding to the laminate produced by the methods can be used. In this aspect, the step performed after the adhering step may further include a dividing step of dividing the pressure-sensitive adhesive sheet and the adherend into the units. The dividing step may be performed at an arbitrary timing after the attaching step. For example, by performing the dividing step after at least the cutting step is finished, the cutting step can be performed for a plurality of units at once. The manufacturing method disclosed herein may be implemented, for example, (a) in such a manner that the above-described dividing step is included between the dicing step and the partial removal step. In the manufacturing method including the adhesive force increasing step after the partial removing step, the method may be performed, for example, in such a manner that the dividing step is included (b) between the partial removing step and the adhesive force increasing step or (c) after the adhesive force increasing step. One or two or more of the above-described modes (a) to (c) may be combined. The above-mentioned embodiment (a) can be preferably carried out using, for example, an adhesive sheet provided with an adhesive layer (2) described later. The above-mentioned aspect (b) and the above-mentioned aspect (c) can be preferably performed using, for example, an adhesive sheet provided with an adhesive layer (1) or an adhesive layer (2) described later.

Production device

The laminate manufacturing method disclosed herein can be implemented using, for example, a laminate manufacturing apparatus 50 as shown in fig. 5, the laminate manufacturing apparatus 50 including: a sticking mechanism 51 for sticking the pressure-sensitive adhesive sheet 20 to the adherend 10, a cutting mechanism 52 for performing cutting processing at the boundary between the first region 21 and the second region 22 of the pressure-sensitive adhesive sheet 20, and a peeling mechanism 53 for leaving the first region 21 on the adherend 10 and peeling and removing the second region 22 from the adherend 10.

The joining mechanism 51 is configured to be able to perform the joining step in any of the manufacturing methods disclosed herein, and may include one or two or more of an adherend supply means, an adhesive sheet supply means, a means for pressure-bonding an adhesive sheet to an adherend, and the like. The cutting mechanism 52 is configured to be able to perform the cutting step in any of the manufacturing methods disclosed herein, and may include one or two or more of the cutting means exemplified above. The peeling mechanism 53 is configured to be able to perform the partial removal step in any of the methods disclosed herein, and may include one or two or more of a pickup means, a holding means, a peeling means, and the like of the second region, for example.

In the laminate manufacturing apparatus that can be used for carrying out the laminate manufacturing method including the embodiment of the adhesive force increasing step, for example, as a mechanism for applying a stimulus for increasing the adhesive force to the first region, an adhesive force increasing mechanism not shown may be further included. The adhesive force increasing mechanism is configured to be capable of performing the adhesive force increasing step in any of the methods disclosed herein by providing the adhesive sheet with a stimulus capable of increasing the adhesive force of the adhesive sheet. The adhesive force increasing mechanism may include one or more of UV irradiation means (UV irradiation lamp, mirror for optical path adjustment, etc.), heating means (hot air heater, infrared heater, electric heater, etc.), pressing means, and the like.

The manufacturing apparatus used in the laminate manufacturing method including the dividing step may further include a dividing mechanism not shown. The dividing mechanism may be configured to perform the dividing step by using a known dividing means such as cutting with a thomson knife, a pointed knife, a rotary knife, or a small knife, or laser cutting, water jet cutting, or blade cutting.

Adhesive sheet

In the following, some examples of adhesive sheets that can be preferably used for carrying out the laminate manufacturing method disclosed herein will be described, but the scope of the present invention is not intended to be limited thereto.

The laminate production method disclosed herein can be preferably carried out using a pressure-sensitive adhesive sheet having a structure including a base material layer and a pressure-sensitive adhesive layer laminated on at least the adherend side of the base material layer. In the pressure-sensitive adhesive sheet having a configuration in which the pressure-sensitive adhesive layer is laminated on the base material layer, the pressure-sensitive adhesive layer can be reinforced by the base material layer, and therefore, the second region can be easily peeled from the adherend in the partial removal step.

< substrate layer >

As the substrate layer, various film substrates can be preferably used. The film substrate may be a porous substrate such as a foamed film or a nonwoven fabric sheet, a non-porous substrate, or a substrate having a structure in which a porous layer and a non-porous layer are laminated. In some embodiments, as the film substrate, a film substrate including a resin film (self-supporting or independent) capable of independently maintaining the shape as a base film can be preferably used. Here, the "resin film" is a non-porous structure, and typically a resin film containing substantially no air bubbles (having no voids). Therefore, the resin film is a concept different from a foamed film and a nonwoven fabric. The resin film may have a single-layer structure or a multilayer structure (for example, a three-layer structure) having two or more layers.

As the resin material constituting the resin film, for example, there can be used: polyamide (PA) such as polyester, polyolefin, nylon 6, nylon 66, and partially aromatic polyamide, Polyimide (PI), polyamide imide (PAI), polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), Polycarbonate (PC), Polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), fluororesin such as Polytetrafluoroethylene (PTFE), acrylic resin, polyacrylate, polystyrene, polyvinyl chloride, and polyvinylidene chloride.

The resin film may be formed using a resin material containing one kind of such resin alone, or may be formed using a resin material obtained by blending two or more kinds of such resins. The resin film may be a non-stretched resin film or a stretched (for example, uniaxially stretched or biaxially stretched) resin film. For example, resin films such as polyethylene terephthalate (PET) film, polyethylene naphthalate (PEN) film, non-stretched polypropylene (CPP) film, biaxially stretched polypropylene (OPP) film, Low Density Polyethylene (LDPE) film, Linear Low Density Polyethylene (LLDPE) film, PP/PE blend film, and the like can be preferably used. Examples of the resin film preferable from the viewpoint of strength and dimensional stability include a PET film, a PEN film, a PPS film, and a PEEK film. From the viewpoint of easy availability, etc., a PET film and a PPS film are particularly preferable, and a PET film is particularly preferable.

The resin film may contain known additives such as a light stabilizer, an antioxidant, an antistatic agent, a colorant (dye, pigment, etc.), a filler, a slip agent, and an antiblocking agent, as necessary, within a range not significantly impairing the effects of the present invention.

The method for producing the resin film is not particularly limited. For example, conventionally known general resin film forming methods such as extrusion molding, inflation molding, T-die casting molding, calender roll molding, and the like can be suitably used.

The base film may substantially constitute the base layer. Alternatively, the base film may further include an auxiliary layer. Examples of the auxiliary layer include: an optical property adjusting layer (e.g., a colored layer, an antireflection layer), a printing layer and/or a lamination layer for imparting a desired appearance to a base material layer, an antistatic layer, an undercoat layer, a release layer, and other surface treatment layers.

The surface of the substrate layer on the side where the pressure-sensitive adhesive layer is laminated may be subjected to conventionally known surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and formation of a primer layer by application of a primer (primer), if necessary. Such a surface treatment may be a treatment for improving the anchoring property of the adhesive layer to the base material layer. The composition of the primer used for forming the undercoat layer is not particularly limited, and may be appropriately selected from known compositions. The thickness of the undercoat layer is not particularly limited, and is usually preferably about 0.01 to 1 μm, and more preferably about 0.1 to 1 μm. As other treatments that may be performed on the base material layer as necessary, there may be mentioned antistatic layer formation treatment, coloring layer formation treatment, printing treatment, and the like. These treatments may be applied alone or in combination.

Adhesive layer

The composition of the adhesive constituting the adhesive layer is not particularly limited. The adhesive may contain 1 or 2 or more of various polymers exhibiting rubber elasticity in a room temperature region, such as acrylic polymers, rubber polymers, polyester polymers, urethane polymers, polyether polymers, silicone polymers, polyamide polymers, and fluorine polymers, which are known in the adhesive field, as base polymers (main components in the polymer components, that is, components having a content of more than 50% by weight). Among them, preferable pressure-sensitive adhesives include acrylic pressure-sensitive adhesives and rubber pressure-sensitive adhesives. Here, the acrylic adhesive means an adhesive containing an acrylic polymer as a base polymer. The same applies to rubber-based adhesives. The acrylic polymer is a polymer in which 50% by weight or more of the total amount of monomer components constituting the acrylic polymer is an acrylic monomer. In the present specification, the acrylic monomer means a monomer having at least one (meth) acryloyl group in 1 molecule. The term "(meth) acryloyl" is intended to cover both acryloyl and methacryloyl.

Several examples of adhesive layers that may be preferably used in the manufacturing methods disclosed herein include: (1) a pressure-sensitive adhesive layer comprising a base polymer and a polymer having a siloxane structure (hereinafter also referred to as "pressure-sensitive adhesive layer (1)"), and (2) a pressure-sensitive adhesive layer comprising a photocurable composition comprising a base polymer and a photocurable agent (hereinafter also referred to as "pressure-sensitive adhesive layer (2)"). The pressure-sensitive adhesive layer (1) and the pressure-sensitive adhesive layer (2) will be described in detail below, but the pressure-sensitive adhesive sheet used in the production method disclosed herein is not limited to the pressure-sensitive adhesive sheet having these pressure-sensitive adhesive layers.

< adhesive layer comprising base Polymer A and Polymer B containing Silicone Structure >

The adhesive layer (1) contains a base polymer a and a polymer B having a siloxane structure, and can exhibit the following properties: after the adhesive is adhered to an adherend, the adhesive strength is suppressed to be low for a long time in a room temperature range (for example, 20 ℃ to 30 ℃), and the adhesive strength is greatly increased by aging (which may be heating, aging, a combination thereof, or the like). Therefore, it can be preferably used for the laminate manufacturing method disclosed herein. The adhesive layer (1) may be formed from an adhesive composition containing a base polymer a or a precursor thereof and containing a polymer B containing a siloxane structure. The form of the pressure-sensitive adhesive composition is not particularly limited, and may be, for example, various forms such as a water dispersion type, a solvent type, a hot melt type, and an active ray-curable type (for example, a UV-curable type).

(base Polymer A)

As the base polymer a (hereinafter, may be abbreviated as "polymer a") of the pressure-sensitive adhesive layer (1), an acrylic polymer can be preferably used. When an acrylic polymer is used as the polymer a, good compatibility with the polymer B tends to be easily obtained. The good compatibility of the polymer a and the polymer B is preferable because it contributes to the realization of the adhesive layer (1) having both low adhesiveness in the partial removal step and strong adhesiveness after the adhesive force-increasing treatment (for example, heat treatment) by increasing the mobility of the polymer B in the adhesive layer. Preferably, 50% by weight or more of the pressure-sensitive adhesive layer (1) is an acrylic polymer.

As the acrylic polymer, for example, an acrylic polymer in which 40% by weight or more of the total amount of monomer components constituting the acrylic polymer is an alkyl (meth) acrylate can be preferably used. As the alkyl (meth) acrylate, those having 1 to 20 carbon atoms (i.e., C) at the ester end can be preferably used_1-20Of (b) a linear or branched alkyl (meth) acrylate. The (meth) acrylic acid C is contained in the total amount of the constituent monomer components of the acrylic polymer in view of easy availability of the balance of characteristics_1-20The proportion of the alkyl ester may be, for example, 50% by weight or more, 55% by weight or more, or 60% by weight or more. For the same reason, (meth) acrylic acid C in the total amount of the constituent monomer components_1-20The proportion of alkyl esters may be, for example, 99.9The content of the organic solvent is not more than 98% by weight, or not more than 95% by weight. In several embodiments, (meth) acrylic acid C in the total amount of monomer components_1-20The proportion of the alkyl ester may be, for example, 90% by weight or less, 85% by weight or less, or 80% by weight or less.

As (meth) acrylic acid C_1-20Non-limiting specific examples of alkyl esters include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, isotridecyl (meth) acrylate, isopropyl, Tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like.

Among them, it is preferable to use at least (meth) acrylic acid C_1-18Alkyl esters, more preferably at least (meth) acrylic acid C_1-14An alkyl ester. In some embodiments, the constituent monomer components of the acrylic polymer may comprise a monomer selected from (meth) acrylic acid C_4-12Alkyl esters (preferably acrylic acid C)_4-10Alkyl esters, e.g. acrylic acid C_6-10Alkyl ester). For example, an acrylic polymer containing one or both of n-Butyl Acrylate (BA) and 2-ethylhexyl acrylate (2EHA) is preferable, and an acrylic polymer containing at least 2EHA is particularly preferable. Other (meth) acrylic acid C which can be preferably used_1-18Examples of alkyl estersExamples of the solvent include: methyl acrylate, Methyl Methacrylate (MMA), n-Butyl Methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), isostearyl acrylate (ISTA), and the like.

The constituent monomer component of the acrylic polymer may contain, as necessary, another monomer (copolymerizable monomer) copolymerizable with the alkyl (meth) acrylate together with the alkyl (meth) acrylate as a main component. As the copolymerizable monomer, a monomer having a polar group (for example, a carboxyl group, a hydroxyl group, etc.) can be suitably used. The monomer having a polar group can contribute to introduction of a crosslinking point into the acrylic polymer or increase the cohesive force of the acrylic polymer. The copolymerizable monomers may be used singly or in combination of two or more.

Specific non-limiting examples of the copolymerizable monomer include the following monomers.

Carboxyl group-containing monomer: such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like.

Hydroxyl group-containing monomer: hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; and monomers having a hydroxyl group and an amide group such as N- (2-hydroxyethyl) acrylamide (HEAA).

Nitrogen-containing monomer: such as N-vinylpyrrolidone, methyl vinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1, 3-oxazin-2-one, N-vinyl-3, 5-morpholinone, N-acryloyl morpholine, N-vinyl carboxylic acid amides and the like.

And cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, epoxy group-containing monomers, vinyl ether monomers, sulfonic group-containing monomers, phosphoric acid group-containing monomers, acid anhydride group-containing monomers, and the like.

When such a copolymerizable monomer is used, the amount thereof is not particularly limited, and is usually preferably 0.01% by weight or more based on the total amount of the monomer components. From the viewpoint of more effectively exhibiting the effects of the use of the copolymerizable monomer, the amount of the copolymerizable monomer to be used may be 0.1% by weight or more, or may be 1% by weight or more, based on the total amount of the monomer components. The amount of the copolymerizable monomer used may be 50% by weight or less, preferably 40% by weight or less, based on the total amount of the monomer components. This prevents the cohesive force of the adhesive from becoming too high, and improves the sense of tackiness at normal temperature (25 ℃).

In some embodiments, the acrylic polymer preferably contains at least one monomer selected from the group consisting of N-vinyl cyclic amides and hydroxyl group-containing monomers as a constituent monomer component thereof.

By using the N-vinyl cyclic amide, the cohesive force and polarity of the adhesive can be adjusted, and the adhesive force after heating as a stimulus for increasing the adhesive force (hereinafter, also referred to as "adhesive force after heating") can be improved. Specific examples of the N-vinylcycloamide include those having a structure corresponding to the nitrogen-containing monomer described above. Particularly preferred examples include N-vinyl-2-pyrrolidone and N-vinyl-2-caprolactam. The amount of the N-vinylcycloamide used is not particularly limited, and is usually preferably 0.01 wt% or more (preferably 0.1 wt% or more, for example, 0.5 wt% or more) of the total amount of the constituent monomer components of the acrylic polymer. In some embodiments, the amount of the N-vinylcycloamide used may be 1 wt% or more, or 5 wt% or more, or 8 wt% or more, or 10 wt% or more, or 12 wt% or more of the total amount of the monomer components. From the viewpoint of improving the sticky feeling at room temperature (25 ℃) and improving the flexibility at low temperature, the amount of the N-vinylcycloamide used is preferably 40 wt% or less, and may be 30 wt% or less, 25 wt% or less, 20 wt% or less, and 18 wt% or less of the total amount of the monomer components.

By using the hydroxyl group-containing monomer, the cohesive force and polarity of the adhesive can be adjusted, and the adhesive force after heating can be improved. The hydroxyl group-containing monomer provides a reaction site with a crosslinking agent (for example, an isocyanate-based crosslinking agent) described later, and the cohesive force of the adhesive can be increased by the crosslinking reaction. Preferred examples of the hydroxyl group-containing monomer include: 2-hydroxyethyl acrylate (HEA), 4-hydroxybutyl acrylate (4HBA), N- (2-hydroxyethyl) acrylamide (HEAA). The amount of the hydroxyl group-containing monomer used is not particularly limited, and is usually preferably 0.01% by weight or more (preferably 0.1% by weight or more, for example, 0.5% by weight or more) of the total amount of the constituent monomer components of the acrylic polymer. In some embodiments, the amount of the hydroxyl group-containing monomer used may be 1% by weight or more, 5% by weight or more, or 10% by weight or more of the total amount of the monomer components. From the viewpoint of improving the sticky feeling at room temperature (25 ℃) and improving the flexibility at low temperature, the amount of the hydroxyl group-containing monomer used is preferably 40% by weight or less, and may be 30% by weight or less, or may be 20% by weight or less, or may be 10% by weight or less, or 5% by weight or less, based on the total amount of the monomer components.

In some embodiments, as the copolymerizable monomer, an N-vinyl cyclic amide and a hydroxyl group-containing monomer may be used in combination. In this case, the total amount of the N-vinylcycloamide and the hydroxyl group-containing monomer may be, for example, 0.1 wt% or more, 1 wt% or more, 5 wt% or more, 10 wt% or more, 15 wt% or more, 20 wt% or more, or 25 wt% or more of the total amount of the constituent monomer components of the acrylic polymer. The total amount of the N-vinylcycloamide and the hydroxyl group-containing monomer may be, for example, 50 wt% or less, preferably 40 wt% or less, based on the total amount of the monomer components.

In the mode of using the N-vinylcycloamide and the hydroxyl group-containing monomer in combination, the amount of the N-vinylcycloamide used (W)_N) And compriseAmount of hydroxyl monomer used (W)_OH) The relationship (weight basis) of (c) is not particularly limited. W_N/W_OHFor example, the content may be 0.01 or more, usually 0.05 or more is suitable, and may be 0.1 or more, 0.2 or more, 0.5 or more, or 0.7 or more. Further, W_N/W_OHFor example, the content may be 100 or less, usually 20 or less is preferable, 10 or less may be used, and 5 or less, 2 or less, 1.5 or less, and 1.3 or less may be used.

The Tg of the polymer A is typically less than 0 deg.C, preferably less than-10 deg.C, more preferably less than-20 deg.C. Since a pressure-sensitive adhesive containing the polymer a having a Tg of less than 0 ℃ exhibits appropriate fluidity (for example, mobility of a polymer chain contained in the pressure-sensitive adhesive), the adhesive strength is likely to be greatly increased by performing heat treatment at an arbitrary timing. In several embodiments, the Tg of polymer A may be, for example, less than-30 deg.C, less than-40 deg.C, less than-50 deg.C, less than-60 deg.C. The lower limit of the Tg of the polymer A is not particularly limited. From the viewpoint of ease of material availability and improvement of the cohesive force of the adhesive layer, it is generally preferable to use the polymer a having a Tg of-80 ℃ or higher.

In this specification, the Tg of a polymer refers to a nominal value described in literature, catalogues, or the like, or a Tg obtained from the Fox formula based on the composition of a monomer component used for producing the polymer. The Fox formula is a relational expression between Tg of a copolymer and glass transition temperature Tgi of a homopolymer obtained by homopolymerizing monomers constituting the copolymer, as shown below.

1/Tg＝Σ(Wi/Tgi)

In the Fox formula, Tg represents the glass transition temperature (unit: K) of the copolymer, Wi represents the weight fraction (weight-based copolymerization ratio) of the monomer i in the copolymer, and Tgi represents the glass transition temperature (unit: K) of the homopolymer of the monomer i. When the subject polymer associated with a particular Tg is a homopolymer, the Tg of the homopolymer is consistent with the Tg of the subject polymer.

The glass transition temperature of the homopolymer used for calculation of Tg was the value described in the publicly known data. Specifically, numerical values are listed in "Polymer Handbook" (3 rd edition, John Wiley & Sons, Inc., 1989). The highest values were used for the monomers having various values described in the above Polymer Handbook.

Although not particularly limited, the weight average molecular weight (Mw) of the polymer a is usually about 5 ten thousand or more, and from the viewpoint of obtaining a pressure-sensitive adhesive showing more favorable cohesion, for example, it may be 10 ten thousand or more, 20 ten thousand or more, 30 ten thousand or more, 50 ten thousand or more, and 70 ten thousand or more. Further, it is generally appropriate that the Mw of the polymer A is about 500 ten thousand or less. Since the polymer a having Mw is easy to form a pressure-sensitive adhesive showing appropriate fluidity (mobility of polymer chains), it is suitable for realizing a pressure-sensitive adhesive sheet having a high increase ratio of adhesive strength. In some embodiments, the Mw of polymer a may be 300 tens of thousands or less, may be 200 tens of thousands or less, and may be 150 tens of thousands or less.

In this specification, the Mw of the polymer can be determined by Gel Permeation Chromatography (GPC) in terms of polystyrene. More specifically, Mw can be measured based on the method and conditions described in the examples below.

The method for obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as a method for synthesizing an acrylic polymer, such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a suspension polymerization method, and a photopolymerization method, can be suitably used.

The initiator used for the polymerization may be suitably selected from conventionally known thermal initiators and photoinitiators according to the polymerization method, and non-limiting examples of the thermal initiator include azo initiators such as 2, 2' -Azobisisobutyronitrile (AIBN), persulfates such as potassium persulfate, peroxide initiators, redox initiators, and the like.

In some embodiments, as a method for obtaining the acrylic polymer, a solution polymerization method may be preferably employed. As a solvent for the solution polymerization, ethyl acetate, toluene, or the like is used. The concentration of the solution is usually about 20 to 80 wt%. As the initiator, various known initiators such as azo type initiators and peroxide type initiators can be used. Chain transfer agents may also be used in order to adjust the molecular weight. The reaction temperature may be usually about 50 to 80 ℃ and the reaction time may be usually about 1 to 8 hours.

In some embodiments, the acrylic polymer may be included in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer in the form of a partial polymer (acrylic polymer syrup) obtained by irradiating a mixture in which the above-described monomer component and the initiator are mixed with Ultraviolet (UV) rays and polymerizing a part of the monomer component. The pressure-sensitive adhesive composition containing the acrylic polymer syrup may be applied to a predetermined object to be coated, and UV irradiation may be performed to terminate the polymerization. That is, the acrylic polymer syrup can be grasped as a precursor of the acrylic polymer. The adhesive layer (1) can be formed using an adhesive composition containing such an acrylic polymer syrup and the polymer B, for example.

(Polymer B having a Silicone Structure)

The polymer B having a siloxane structure (hereinafter sometimes simply referred to as "polymer B") is a copolymer of a monomer having a polyorganosiloxane skeleton (hereinafter also referred to as "monomer S1") and a (meth) acrylic monomer. The polymer B can function as an adhesion force increase retarder contributing to suppression of initial adhesion force and improvement of the adhesion force increase ratio due to low polarity and mobility of the polyorganosiloxane structure derived from the monomer S1. The monomer S1 is not particularly limited, and any monomer having a polyorganosiloxane skeleton can be used. The monomer S1 promotes the uneven distribution of the polymer B on the surface of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet before use (before attachment to an adherend) due to its low polarity derived from its structure, and exhibits light peelability (low adhesiveness) at the time of initial attachment. As the monomer S1, a monomer having a structure having a polymerizable reactive group at one end can be preferably used. By copolymerization of the monomer S1 and the (meth) acrylic monomer, a polymer B having a polyorganosiloxane skeleton in the side chain is formed. The polymer B having such a structure is likely to be a polymer having a low initial adhesion and a high increase ratio of adhesion due to the mobility and ease of movement of the side chain.

As the monomer S1, for example, a compound represented by the following general formula (1) or (2) can be used. More specifically, examples of the single-terminal reactive silicone oil manufactured by shin-Etsu chemical industries include X-22-174ASX, X-22-2426, X-22-2475, and KF-2012. The monomer S1 may be used singly or in combination of two or more.

Here, R in the above general formulae (1) and (2)³Is hydrogen or methyl, R⁴Is methyl or a 1-valent organic group, and m and n are integers of 0 or more.

The functional group equivalent of the monomer S1 is, for example, preferably 700g/mol or more and less than 15000g/mol, more preferably 800g/mol or more and less than 10000g/mol, still more preferably 850g/mol or more and less than 6000g/mol, and particularly preferably 1500g/mol or more and less than 5000 g/mol. When the functional group equivalent of the monomer S1 is less than 700g/mol, the initial adhesive force may not be sufficiently suppressed. When the functional group equivalent of the monomer S1 is 15000g/mol or more, the increase in adhesive force may be insufficient. When the functional group equivalent of the monomer S1 is within the above range, the compatibility (for example, compatibility with the polymer a) in the pressure-sensitive adhesive layer and the mobility can be easily adjusted within an appropriate range, and a pressure-sensitive adhesive sheet having both the initial low adhesiveness and the strong adhesiveness when used as a laminate can be easily realized at a high level.

Here, "functional group equivalent" refers to the weight of the main skeleton (for example, polydimethylsiloxane) bonded to each functional group. The labeling unit g/mol was converted to 1mol of the functional group. The functional equivalent of the monomer S1 can be determined, for example, by Nuclear Magnetic Resonance (NMR)¹The spectral intensity of H-NMR (proton NMR) was calculated. Based on¹Functional group of monomer S1 of spectral intensity of H-NMRThe calculation of the amount (g/mol) can be based on¹A general structure analysis method in H-NMR spectroscopy is carried out as necessary with reference to the description of Japanese patent No. 5951153.

When two or more monomers having different functional group equivalents are used as the monomer S1, an arithmetic average value can be used as the functional group equivalent of the monomer S1. That is, n kinds of monomers having different functional group equivalent weights (monomer S1)₁Monomer S1₂Monomer S1_n) The functional group equivalent of the monomer S1 (2) can be calculated by the following formula.

Functional group equivalent (g/mol) of monomer S1 ═ monomer S1₁Functional group equivalent of (2) monomer S1₁Amount of blending + monomer S1₂Functional group equivalent of (2) monomer S1₂Of (c) amount of + monomer S1_nFunctional group equivalent of (2) monomer S1_n(ii) compounding amount)/(monomer S1₁Amount of blending + monomer S1₂Of (c) amount of + monomer S1_nAmount of (2)

The content of the monomer S1 may be, for example, 5% by weight or more based on the total monomer components used for producing the polymer B, and is preferably 10% by weight or more, may be 15% by weight or more, and may be 20% by weight or more from the viewpoint of better exerting the effect as a retardation agent for increasing the adhesive force. The content of the monomer S1 is preferably 60% by weight or less, and may be 50% by weight or less, or 40% by weight or less, or 30% by weight or less, based on the total monomer components used for producing the polymer B, from the viewpoint of polymerization reactivity and compatibility. When the content of the monomer S1 is less than 5% by weight, the initial adhesion may not be sufficiently suppressed. When the content of the monomer S1 is more than 60% by weight, the increase in adhesive force may be insufficient.

The monomer component used for the preparation of the polymer B contains a (meth) acrylic monomer copolymerizable with the monomer S1 in addition to the monomer S1. By copolymerizing one or two or more (meth) acrylic monomers with the monomer S1, the mobility of the polymer B in the adhesive layer can be appropriately adjusted. Copolymerizing monomer S1 with a (meth) acrylic monomer can also help to improve the compatibility of polymer B with polymer a (e.g., an acrylic polymer).

Examples of the (meth) acrylic monomer include alkyl (meth) acrylates. For example, as the copolymerization component of the polymer B, one or more of the monomers exemplified above as the alkyl (meth) acrylate that can be used when the polymer a is an acrylic polymer can be used. In several embodiments, polymer B may contain (meth) acrylic acid C_4-12Alkyl esters (preferably C (meth) acrylic acid)_4-10Alkyl esters, e.g. C (meth) acrylate_6-10Alkyl ester) as monomer units. In other embodiments, polymer B may comprise methacrylic acid C_1-18Alkyl esters (preferably methacrylic acid C)_1-14Alkyl esters, e.g. methacrylic acid C_1-10Alkyl ester) as monomer units. The monomer unit constituting the polymer B may include, for example, one or two or more selected from MMA, BMA, and 2 EHMA.

Other examples of the (meth) acrylic monomer include (meth) acrylates having an alicyclic hydrocarbon group. For example, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, 1-adamantyl (meth) acrylate, and the like can be used. In some embodiments, polymer B may comprise at least one selected from the group consisting of dicyclopentanyl methacrylate, isobornyl methacrylate, and cyclohexyl methacrylate as a monomer unit.

The amount of the alkyl (meth) acrylate and the (meth) acrylate having an alicyclic hydrocarbon group used may be, for example, 10% by weight or more and 95% by weight or less, 20% by weight or more and 95% by weight or less, 30% by weight or more and 90% by weight or less, 40% by weight or more and 90% by weight or less, or 50% by weight or more and 85% by weight or less based on the total monomer components used for preparing the polymer B.

Other examples of monomers that can be contained together with the monomer S1 as monomer units constituting the polymer B include: the monomer that can be used when the polymer a is an acrylic polymer is exemplified by the various copolymerizable monomers described above.

In some embodiments, by including a monomer unit common to the monomer unit included in the polymer B in the polymer a, the mobility of the polymer B in the pressure-sensitive adhesive layer can be improved, and the adhesion increasing ratio can be increased. The common monomer unit is effective to occupy 5% by weight or more of the total monomer units constituting the polymer B, and preferably occupies 10% by weight or more (more preferably 20% by weight or more, for example 30% by weight or more). The proportion of the common monomer unit in the total monomer units constituting the polymer a may be, for example, 1% by weight or more, preferably 3% by weight or more, more preferably 5% by weight or more, or 7% by weight or more. When the proportion of the common monomer unit in all the monomer units constituting the polymer a is high, the effect of improving the compatibility tends to be more exhibited. In view of balance with other characteristics, the proportion of the common monomer unit in the total monomer units constituting the polymer a may be 50% by weight or less, 30% by weight or less, or 15% by weight or less. Non-limiting examples of monomers that can be preferably used as the common monomer unit include: MMA, BMA, 2EHMA, Methyl Acrylate (MA), BA, 2EHA, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and the like.

The Mw of the polymer B is not particularly limited. The Mw of the polymer B may be, for example, 1000 or more, or 5000 or more. From the viewpoint of improving the adhesive force increasing property by heating, in some embodiments, the Mw of the polymer B may be, for example, 10000 or more, 12000 or more, 15000 or more, 17000 or more, 20000 or more. The Mw of the polymer B may be, for example, 500000 or less, or 350000 or less. In some embodiments, the Mw of the polymer B may be, for example, 100000 or less, or 70000 or less, or 50000 or less, or less than 50000, or less than 40000 or less than 35000, or 30000 or less, 28000 or less, or 25000 or less, from the viewpoint of facilitating the peeling of the second region from the adherend in the partial removal step. When the Mw of the polymer B is within any of the above upper limit and lower limit, it is easy to adjust the compatibility and mobility in the pressure-sensitive adhesive layer to appropriate ranges, and it is easy to achieve both low adhesiveness in the partial removal step and strong adhesiveness in use of the laminate at a high level.

The polymer B can be produced by polymerizing the above-mentioned monomers by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, or photopolymerization.

Examples of the chain transfer agent to be used include compounds having a mercapto group such as octyl mercaptan, lauryl mercaptan, tert-nonyl mercaptan, tert-dodecyl mercaptan, mercaptoethanol, α -thioglycerol, thioglycolic acid esters such as methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, tert-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate, dodecyl thioglycolate, thioglycolate of ethylene glycol, thioglycolate of neopentyl glycol, thioglycolate of pentaerythritol, α -methylstyrene dimer, and the like.

The amount of the chain transfer agent to be used is not particularly limited, and is usually suitably 0.05 to 20 parts by weight, preferably 0.1 to 15 parts by weight, and more preferably 0.2 to 10 parts by weight, based on 100 parts by weight of the monomer. By adjusting the amount of the chain transfer agent in this manner, a polymer B having an appropriate molecular weight can be obtained. The chain transfer agent may be used singly or in combination of two or more.

Although not particularly limited, the amount of the polymer B to be used may be, for example, 0.1 part by weight or more relative to 100 parts by weight of the amount of the polymer a, and from the viewpoint of obtaining higher effects, may be 0.3 part by weight or more, may be 0.4 part by weight or more, and may be 0.5 part by weight or more, 1 part by weight or more, or 2 parts by weight or more. From the viewpoint of avoiding an excessive decrease in cohesive force, the amount of the polymer B to be used may be, for example, 75 parts by weight or less, 50 parts by weight or less, 20 parts by weight or less, 10 parts by weight or less, 8 parts by weight or less, or 5 parts by weight or less, relative to 100 parts by weight of the polymer a.

The pressure-sensitive adhesive layer may contain a polymer (an arbitrary polymer) other than the polymer a and the polymer B as necessary within a range not to substantially impair the effects obtained by the technique disclosed herein. The amount of such an arbitrary polymer is usually set to 20% by weight or less of all polymer components contained in the adhesive layer. In some embodiments, the amount of the optional polymer may be 5 wt% or less, or 1 wt% or less of the total amount of the polymer components. The pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer substantially free of polymers other than the polymer a and the polymer B.

(crosslinking agent)

In the pressure-sensitive adhesive layer, a crosslinking agent may be used as needed for the purpose of adjusting the cohesive force and the like. As the crosslinking agent, crosslinking agents known in the field of adhesives can be used, and examples thereof include: isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, metal chelate-based crosslinking agents, and the like. Particularly preferred are isocyanate-based crosslinking agents, epoxy-based crosslinking agents and metal chelate-based crosslinking agents. The crosslinking agent may be used singly or in combination of two or more. The technique disclosed herein can be preferably carried out by using at least an isocyanate-based crosslinking agent as the crosslinking agent.

Examples of the isocyanate-based crosslinking agent include: lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2, 4-tolylene diisocyanate, 4' -diphenylmethane diisocyanate, and xylylene diisocyanate; trimethylolpropane/tolylene diisocyanate trimer adduct (e.g., "CORONATE L" manufactured by Tosoh Corp.), trimethylolpropane/hexamethylene diisocyanate trimer adduct (e.g., "CORONATE HL" manufactured by Tosoh Corp.), and xylylene diisocyanate trimer adduct (e.g., "TAKENATE D110N" manufactured by Mitsui Kagaku., isocyanurate (e.g., "CORONATE HX" manufactured by Tosoh Corp.), and the like.

Examples of the epoxy crosslinking agent include: bisphenol a, an epoxy resin of the epichlorohydrin type, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerol triglycidyl ether, 1, 6-hexanediol glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diamine glycidyl amine, N' -tetraglycidyl-m-xylylenediamine, 1, 3-bis (N, N-diglycidylaminomethyl) cyclohexane, and the like.

The amount of the crosslinking agent used is not particularly limited, and may be, for example, more than 0 part by weight based on 100 parts by weight of the polymer a. In some embodiments, the amount of the crosslinking agent used may be, for example, 0.01 parts by weight or more, 0.05 parts by weight or more, 0.1 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more, 1.5 parts by weight or more, or 2 parts by weight or more, relative to 100 parts by weight of the polymer a. By increasing the amount of the crosslinking agent, higher cohesive force tends to be obtained. On the other hand, from the viewpoint of avoiding a decrease in viscosity due to an excessive increase in cohesive force, the amount of the crosslinking agent to be used is usually preferably 15 parts by weight or less, and may be 10 parts by weight or less, and may be 5 parts by weight or less, relative to 100 parts by weight of the polymer a. An excessive amount of the crosslinking agent is advantageous from the viewpoint of better expressing the effect of using the polymer B by utilizing the fluidity of the binder.

In order to more efficiently perform the crosslinking reaction, a crosslinking catalyst may also be used. Examples of the crosslinking catalyst include: metal-based crosslinking catalysts such as tetra-n-butyl titanate, tetra-isopropyl titanate, iron acetylacetonate, butyltin oxide, and dioctyltin dilaurate. Among them, tin-based crosslinking catalysts such as dioctyltin dilaurate are preferable. The amount of the crosslinking catalyst to be used is not particularly limited, and may be, for example, about 0.0001 to 1 part by weight (typically 0.05 part by weight or less) per 100 parts by weight of the polymer a.

The pressure-sensitive adhesive layer may use a polyfunctional monomer as necessary. The polyfunctional monomer can contribute to the purpose of adjusting the cohesive force or the like by using it in place of the above-mentioned crosslinking agent or in combination with the crosslinking agent. For example, in the pressure-sensitive adhesive layer formed of the photocurable pressure-sensitive adhesive composition, a polyfunctional monomer can be preferably used.

Examples of the polyfunctional monomer include: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ethylene glycol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 12-dodecanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, allyl (meth) acrylate, vinyl (meth) acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyl glycol (meth) acrylate, styrene-acrylate, hexyl glycol di (meth) acrylate, and the like. Of these, trimethylolpropane tri (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, dipentaerythritol hexa (meth) acrylate can be suitably used. The polyfunctional monomer may be used alone or in combination of two or more.

The amount of the polyfunctional monomer used varies depending on the molecular weight, the number of functional groups, and the like, and is usually suitably in the range of about 0.01 to 3.0 parts by weight based on 100 parts by weight of the polymer a. In some embodiments, the amount of the polyfunctional monomer used may be, for example, 0.02 parts by weight or more and may be 0.03 parts by weight or more, based on 100 parts by weight of the polymer a. By increasing the amount of the polyfunctional monomer, higher cohesive force tends to be obtained. On the other hand, the amount of the polyfunctional monomer used may be 2.0 parts by weight or less, 1.0 parts by weight or less, or 0.5 parts by weight or less based on 100 parts by weight of the polymer a, from the viewpoint of avoiding a decrease in viscosity due to an excessive increase in cohesive force. When the amount of the polyfunctional monomer used is not too large, it is also advantageous from the viewpoint of better exhibiting the effect of using the polymer B by utilizing the fluidity of the binder.

(tackifying resin)

The adhesive layer may contain a tackifier resin if necessary. The tackifier resin is not particularly limited, and examples thereof include: rosin-based tackifying resins, terpene-based tackifying resins, phenol-based tackifying resins, hydrocarbon-based tackifying resins, ketone-based tackifying resins, polyamide-based tackifying resins, epoxy-based tackifying resins, elastic-based tackifying resins, and the like. The tackifier resins may be used singly or in combination of two or more.

In the embodiment in which the pressure-sensitive adhesive layer contains a tackifier resin, the content of the tackifier resin is not particularly limited, and may be set so as to exhibit an appropriate adhesive performance in accordance with the purpose and use. The content of the tackifier resin (the total amount of two or more tackifier resins when included) may be, for example, about 5 to 500 parts by weight relative to 100 parts by weight of the polymer a. It should be noted that the technology disclosed herein can also be preferably implemented in the following manner: a mode in which the content of the tackifier resin is less than 5 parts by weight, less than 2 parts by weight, or less than 1 part by weight, relative to 100 parts by weight of the polymer a; or the adhesive layer does not substantially contain a tackifier resin.

As the tackifier resin, a tackifier resin having a softening point (softening temperature) of about 80 ℃ or higher (preferably about 100 ℃ or higher, for example, about 120 ℃ or higher) can be preferably used. The tackifier resin having a softening point of not less than the lower limit tends to effectively improve the initial low tackiness and the strong tackiness in use of the laminate. The upper limit of the softening point is not particularly limited, and may be, for example, about 200 ℃ or lower (typically 180 ℃ or lower). The softening point of the tackifier resin can be measured according to the softening point test method (ring and ball method) specified in JIS K2207.

(formation of adhesive layer)

The adhesive layer (1) may be a cured layer of the adhesive composition. That is, the adhesive layer (1) can be formed by applying an adhesive composition of an aqueous dispersion type, a solvent type, a photocurable type, a hot melt type, or the like to an appropriate surface and then appropriately performing a curing treatment. When two or more curing treatments (drying, crosslinking, polymerization, cooling, etc.) are performed, they may be performed simultaneously or in multiple stages. In the adhesive composition using a partial polymer (acrylic polymer syrup) of a monomer component, a final copolymerization reaction is typically performed as the curing treatment. That is, a portion of the polymer is subjected to further copolymerization to form a complete polymer. For example, in the case of a photocurable adhesive composition, light irradiation is performed. If necessary, curing treatment such as crosslinking and drying may be performed. For example, when the pressure-sensitive adhesive composition is a photocurable pressure-sensitive adhesive composition and needs to be dried, it may be cured by light after drying. The adhesive composition using a complete polymer is typically subjected to a treatment such as drying (heat drying) or crosslinking as necessary as the curing treatment.

The application of the adhesive composition can be carried out using a conventional coater such as a gravure roll coater, a reverse roll coater, a dip roll coater, a bar coater, a knife coater, or a spray coater. The application of the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer (2) described later and other pressure-sensitive adhesive compositions can be performed in the same manner.

< adhesive layer formed from photocurable composition comprising base polymer P and photocurable agent >

The adhesive layer (2) contains a base polymer P and a light curing agent, and exhibits a property of being cured by irradiation with active light (e.g., UV) to increase the adhesive force. Taking advantage of this property, for example, the implementation of the laminate manufacturing method disclosed herein can be suitably used in the following manner: the adhesive strength before photocuring is 2N/25mm or less, and the adhesive strength is increased (typically to 5N/25mm or more) by performing a pasting step, a dicing step, and a partial removal step before the photocuring and then photocuring. The adhesive composition (photocurable composition) constituting the adhesive layer (2) preferably contains a photoinitiator from the viewpoint of improving the efficiency of curing by irradiation with active light. In view of hardening the pressure-sensitive adhesive layer before photocuring and suppressing a phenomenon in which the pressure-sensitive adhesive remains on the adherend when the pressure-sensitive adhesive sheet in the second region is peeled off and removed in the partial removal step, that is, a residual adhesive phenomenon, it is preferable to introduce a crosslinked structure into the base polymer P.

(base Polymer P)

As the base polymer P of the pressure-sensitive adhesive layer (2) (hereinafter, may be simply referred to as "polymer P"), an acrylic polymer can be preferably used from the viewpoint of optical transparency and the like. For example, 50% by weight or more of the pressure-sensitive adhesive layer (2) is preferably an acrylic polymer. As the acrylic polymer, an acrylic polymer containing an alkyl (meth) acrylate in an amount of 40% by weight or more of the total amount of the constituent monomer components, the same as that of the polymer A, can be preferably used.

The acrylic polymer preferably contains a monomer component having a crosslinkable functional group as a copolymerization component. Examples of the monomer having a crosslinkable functional group include a hydroxyl group-containing monomer and a carboxyl group-containing monomer. Examples of the hydroxyl group-containing monomer and the carboxyl group-containing monomer include the same monomers as exemplified as the constituent monomer components of the polymer a contained in the pressure-sensitive adhesive layer (1). Among them, a hydroxyl group-containing monomer is preferably contained. The hydroxyl group and the carboxyl group of the polymer P serve as reaction sites with a crosslinking agent described later. By introducing a crosslinked structure into the polymer P, the cohesive force is improved, the adhesiveness of the pressure-sensitive adhesive layer (2) is improved, and the fluidity of the pressure-sensitive adhesive is reduced, so that the residual adhesive on the adherend tends to be reduced in the partial removal step.

The acrylic polymer preferably contains 1 to 30 wt%, more preferably 3 to 25 wt%, and still more preferably 5 to 20 wt% of the total amount of the hydroxyl group-containing monomer and the carboxyl group-containing monomer with respect to the total amount of the constituent monomer components. It is particularly preferable that the content of the hydroxyl group-containing (meth) acrylate is in the above range.

The acrylic polymer preferably contains a nitrogen-containing monomer as a constituent monomer component. Examples of the nitrogen-containing monomer include the same monomers as those exemplified as the constituent monomer component of the polymer a contained in the pressure-sensitive adhesive layer (1). The content of the nitrogen-containing monomer is preferably 1 to 30% by weight, more preferably 3 to 25% by weight, and further preferably 5 to 20% by weight based on the total amount of the constituent monomer components. The acrylic polymer preferably contains N-vinylpyrrolidone as a nitrogen-containing monomer in the above-mentioned range.

In the case where the acrylic polymer contains both a hydroxyl group-containing monomer and a nitrogen-containing monomer as monomer components, the cohesive force and transparency of the adhesive tend to be improved. The acrylic polymer preferably contains 5 to 50 wt%, more preferably 10 to 40 wt%, and still more preferably 15 to 35 wt% of the total amount of the hydroxyl group-containing monomer and the nitrogen-containing monomer with respect to the total amount of the constituent monomer components.

The acrylic polymer may further contain monomer components other than those described above, such as a cyano group-containing monomer, a vinyl ester monomer, an aromatic vinyl monomer, an epoxy group-containing monomer, a vinyl ether monomer, a sulfonic group-containing monomer, a phosphoric group-containing monomer, an acid anhydride group-containing monomer, and the like.

In the acrylic polymer, the content of the monomer having a homopolymer Tg of 40 ℃ or higher is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, based on the total amount of the monomer components constituting the acrylic polymer. From the viewpoint of suppressing the residual gum in the partial removal step, the constituent monomer component of the polymer P preferably contains a monomer component having a homopolymer Tg of 80 ℃ or higher, and more preferably contains a monomer component having a homopolymer Tg of 100 ℃ or higher. In the acrylic polymer, the content of the monomer having a Tg of 100 ℃ or higher is preferably 0.1% by weight or higher, more preferably 0.5% by weight or higher, further preferably 1% by weight or higher, and particularly preferably 3% by weight or higher, relative to the homopolymer constituting the total amount of the monomer components. It is particularly preferable that the MMA content is in the above range. The suitable range of Tg of the acrylic polymer used as the polymer P may be the same as the suitable Tg of the polymer a.

The acrylic polymer can be obtained by a known polymerization method in the same manner as the polymer a contained in the pressure-sensitive adhesive layer (1). For example, the solution polymerization method can be preferably used.

The adhesion of the pressure-sensitive adhesive layer before photocuring is easily affected by the constituent components and molecular weight of the polymer P. From the viewpoint of satisfying both appropriate adhesiveness and suppression of residual gum in the partial removal step, the weight average molecular weight of the acrylic polymer is preferably 10 to 500 ten thousand, more preferably 30 to 300 ten thousand, and further preferably 50 to 200 ten thousand. When a crosslinked structure is introduced into the polymer P, the molecular weight of the polymer P is the molecular weight before introduction of the crosslinked structure.

(crosslinking agent)

From the viewpoint of imparting a proper cohesive force to the pressure-sensitive adhesive, it is preferable to introduce a crosslinked structure into the polymer P. For example, a crosslinking structure is introduced by adding a crosslinking agent to a solution after polymerization of the polymer P and heating the solution as necessary. Examples of the crosslinking agent include: isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, metal chelate-based crosslinking agents, and the like. These crosslinking agents react with functional groups such as hydroxyl groups introduced into the polymer P to form a crosslinked structure. As the isocyanate-based crosslinking agent, the same crosslinking agent as that of the pressure-sensitive adhesive layer (1) can be used.

The amount of the crosslinking agent to be used may be appropriately adjusted depending on the composition, molecular weight, etc. of the polymer P. The amount of the crosslinking agent to be used may be, for example, about 0.1 to 10 parts by weight, preferably 0.3 to 7 parts by weight, more preferably 0.5 to 5 parts by weight, and still more preferably 1 to 4 parts by weight, based on 100 parts by weight of the polymer P. In order to promote the formation of the crosslinked structure, a crosslinking catalyst may be used in the same manner as in the pressure-sensitive adhesive layer (1).

(light curing agent)

The adhesive composition constituting the adhesive layer (2) is configured to exhibit photocurability by containing a photocuring agent in addition to the polymer P. The pressure-sensitive adhesive layer (2) exhibits properties of increasing the adhesive strength by photocuring when irradiated with active light as a stimulus for increasing the adhesive strength after being bonded to an adherend.

As the photocuring agent, a photocurable monomer or a photocurable oligomer is used. As the light curing agent, a compound having 2 or more ethylenically unsaturated bonds in 1 molecule is preferable. Further, the light curing agent is preferably a compound showing compatibility with the polymer P. From the viewpoint of exhibiting appropriate compatibility with the polymer P, the light curing agent is preferably liquid at ordinary temperature. The light curing agent is compatible with the polymer P and uniformly dispersed in the composition, so that a contact area with an adherend can be secured, and the pressure-sensitive adhesive layer (2) having high transparency can be formed.

The compatibility of the polymer P with the photocuring agent is mainly influenced by the structure of the compound. The structure and compatibility of the compound can be evaluated by, for example, hansen solubility parameters, and there is a tendency that the smaller the difference between the solubility parameters of the polymer P and the photocurable agent, the higher the compatibility.

From the viewpoint of high compatibility with the acrylic polymer, it is preferable to use a polyfunctional (meth) acrylate as the light curing agent. Examples of the polyfunctional (meth) acrylate include: polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, bisphenol A ethylene oxide-modified di (meth) acrylate, bisphenol A propylene oxide-modified di (meth) acrylate, alkane diol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, ethoxylated isocyanuric acid tri (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, dipentaerythritol poly (meth) acrylate, dipentaerythritol hexa (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol poly (meth) acrylate, pentaerythritol hexa (meth) acrylate, and mixtures thereof, Glycerin di (meth) acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, butadiene (meth) acrylate, isoprene (meth) acrylate, and the like.

The compatibility of the polymer P with the photocuring agent also depends on the molecular weight of the compound. The smaller the molecular weight of the photocurable compound is, the higher the compatibility with the polymer P tends to be. The molecular weight of the light curing agent is preferably 1500 or less, more preferably 1000 or less, from the viewpoint of compatibility with the polymer P.

The type and content of the light curing agent mainly affect the adhesion after light curing. The smaller the functional group equivalent (i.e., the larger the number of functional groups per unit molecular weight), the larger the content of the photo-curing agent, the larger the adhesive force after photo-curing tends to be.

From the viewpoint of improving the adhesive force after photocuring, the functional group equivalent (g/eq) of the photocuring agent is preferably 500 or less, more preferably 450 or less. On the other hand, when the photocrosslinking density is excessively increased, the tackiness of the adhesive is lowered and the adhesive force is sometimes lowered. Therefore, the functional group equivalent of the photocurable agent is preferably 100 or more, more preferably 130 or more, further preferably 150 or more, and particularly preferably 180 or more.

For the combination of acrylic polymer and multifunctional acrylate photocuring agent, there are lower orientations: when the functional group equivalent of the photocurable agent is small, the interaction between the polymer P and the photocurable agent is strong, and the adhesive force before photocuring becomes high. In the technique disclosed herein, it is also preferable that the functional group equivalent of the photocurable agent is within the above range from the viewpoint of suppressing the adhesive force before photocuring to an appropriate range to improve the removability of the second region in the partial removal step.

The content of the light curing agent in the adhesive composition is preferably 1 to 50 parts by weight, more preferably 5 to 40 parts by weight, and still more preferably 10 to 35 parts by weight, based on 100 parts by weight of the polymer P. The photocurable compound is contained in the adhesive composition in the form of an uncured (unreacted) monomer or oligomer, whereby a photocurable adhesive layer can be obtained. In order to allow the light curing agent to be included in the composition in an uncured state, it is preferable to add the light curing agent to a polymer solution after the polymerization of the polymer P.

When the content of the light curing agent in the pressure-sensitive adhesive composition is increased, the light curing agent easily bleeds out on the surface of the pressure-sensitive adhesive layer. If the light curing agent bleeds out in a large amount, the light curing agent tends to remain on the adherend after the second region is removed. On the other hand, when a small amount of the light curing agent is exuded on the surface, the adhesive force of the pressure-sensitive adhesive layer to the adherend can be suppressed, and the low adhesiveness before the light curing and the strong adhesiveness after the light curing can be suitably satisfied at the same time.

(photoinitiator)

The adhesive layer (2) preferably contains a photoinitiator. The photoinitiator generates active species by irradiation of active rays, and promotes a curing reaction of the photocurable agent. As the photoinitiator, a photo cation initiator (photo acid generator), a photo radical initiator, a photo anion initiator (photo base generator), or the like can be used depending on the kind of the photo curing agent or the like. When a polyfunctional acrylate is used as the photo-curing agent, a photo radical initiator is preferably used. Examples of the photo radical initiator include: hydroxyketones, benzildimethylketals, aminoketones, acylphosphine oxides, benzophenones, trichloromethyl-containing triazine derivatives, and the like. The photo radical generators may be used alone or in combination of 2 or more. The content of the photoinitiator in the adhesive layer is preferably 0.001 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the total amount of the adhesive layer.

(other additives)

The pressure-sensitive adhesive layer may contain additives such as a silane coupling agent, a tackifier, a plasticizer, a softening agent, an anti-deterioration agent, a filler, a coloring agent, an ultraviolet absorber, an antioxidant, a surfactant, and an antistatic agent in addition to the above-described components as long as the effects obtained by the technique disclosed herein are not significantly impaired.

(formation of adhesive layer)

The adhesive layer (2) can be formed, for example, as follows: the adhesive composition is formed by applying an adhesive composition containing the polymer P, a light curing agent, and other components used as needed to an appropriate surface, and then drying and removing the solvent as needed. As the drying method, an appropriate method can be suitably employed. The heating and drying temperature is preferably 40 to 200 ℃, more preferably 50 to 180 ℃, and still more preferably 70 to 170 ℃. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and further preferably 10 seconds to 10 minutes.

When the pressure-sensitive adhesive composition contains a crosslinking agent, it is preferable to carry out crosslinking by heating or curing simultaneously with or after drying of the solvent. The heating temperature and the heating time are appropriately set depending on the kind of the crosslinking agent used, and the crosslinking is usually performed by heating in the range of 20 to 160 ℃ for about 1 minute to 7 days. The heating for drying off the solvent can also be used simultaneously as heating for crosslinking. The photocurable agent also remains unreacted after the crosslinked structure is introduced into the polymer by the crosslinking agent. Thus, a photocurable adhesive layer (2) containing the polymer P having a crosslinked structure introduced therein and an unreacted photocurable agent is formed.

(frictional force)

The adhesive layer (2) before photocuring is preferably 2 to 5 times as high as the friction force at a frequency of 0.1Hz, as measured by the tapping mode of a Friction Force Microscope (FFM), from the viewpoint of easily suppressing the adhesive force. When the ratio of the frequency of the pressure-sensitive adhesive layer (2) to the frictional force of 5Hz is in this range, the adhesive force after photocuring tends to be significantly higher than that before photocuring.

In the FFM, a force acting between a probe of a Scanning Probe Microscope (SPM) and a sample surface is converted into a displacement (a distortion amount) of a leaf spring of a cantilever, and the displacement is electrically detected. The amount of displacement is proportional to the differential voltage, and the frictional force is proportional to the spring constant and the amount of displacement of the cantilever. Therefore, the friction force is proportional to the FFM difference voltage. The ratio of the friction force at the frequency of 5Hz to the friction force at the frequency of 0.1Hz is equal to the ratio of the FFM difference signals of the two.

The friction force based on the nanomotology tends to reflect the adhesiveness between the surface of the pressure-sensitive adhesive layer and the adherend, and a small friction force means that the surface of the pressure-sensitive adhesive is close to a liquid state and has a small viscosity. In the case where the surface of the adhesive layer has tackiness, the frictional force becomes large, and the frictional force measured by FFM shows frequency dependence. The frictional force measured at a specific frequency tends to reflect the physical properties of the respective constituent components of the pressure-sensitive adhesive composition, whereas the frequency dependence tends to reflect the surface properties more accurately. The smaller the frequency dependence of the frictional force is, the lower the viscosity is and the stronger the liquid state property is, and the larger the frequency dependence of the frictional force is, the higher the viscosity is and the higher the adhesiveness to the adherend tends to be. For example, when the base polymer of the pressure-sensitive adhesive Layer and the light-curing agent are not completely compatible, the liquid light-curing agent bleeds out on the surface, and a Weak interface Layer (WBL) is formed at the bonding interface with the adherend, and the liquid property is enhanced, and thus the frictional force and the frequency dependence of the frictional force tend to be reduced.

By controlling the compatibility of the polymer P in the adhesive layer (2) with the photocuring agent, a small amount of the photocuring agent sometimes bleeds out on the surface of the adhesive layer to form a WBL. When WBLs are appropriately formed, the characteristics of the surface (bonding interface) change, and the frictional force and the frequency dependence of the frictional force become small. This makes it easier to suppress the adhesive force before photocuring, and the second region is easily peeled off when the partial removal step is performed before the photocuring.

When the friction force of the pressure-sensitive adhesive layer before photocuring at a frequency of 5Hz is 5 times or less the friction force at a frequency of 0.1Hz, the pressure-sensitive adhesive layer before photocuring tends to be easily peeled from an adherend. From the viewpoint of avoiding bleeding of the light curing agent, the frictional force of the pressure-sensitive adhesive layer at a frequency of 5Hz is preferably 2 times or more, more preferably 3 times or more, and still more preferably 3.5 times or more the frictional force at a frequency of 0.1 Hz.

From the viewpoint of satisfying both of appropriate adhesiveness to an adherend and peelability, the FFM difference signal at a frequency of 5Hz of the pressure-sensitive adhesive layer before photocuring measured using a cantilever having a spring constant of 40N/m is preferably 0.01 to 1V, more preferably 0.05 to 0.9V, further preferably 0.1 to 0.8V, and particularly preferably 0.2 to 0.7V.

From the viewpoint of improving the adhesive force after photocuring, the frictional force at a frequency of 5Hz of the pressure-sensitive adhesive layer after photocuring as measured by FFM is preferably 5 times or more, more preferably 5.5 times or more the frictional force at a frequency of 0.1 Hz. The FFM difference signal at a frequency of 5Hz of the pressure-sensitive adhesive layer after photocuring, which is measured using a cantilever having a spring constant of 40N/m, is preferably 0.1V or more, more preferably 0.2V or more, and still more preferably 0.3V or more. From the viewpoint of improving the adhesive strength, the larger the frictional force of the pressure-sensitive adhesive layer after photocuring, the more preferable. Therefore, the upper limit of the frictional force is not particularly limited, and the FFM difference signal at 5Hz measured using a cantilever having a spring constant of 40N/m is usually 10V or less, and preferably 5V or less in consideration of the balance of the properties of the adhesive.

The friction force at a frequency of 5Hz of the pressure-sensitive adhesive layer after photocuring is preferably 1.5 times or more, more preferably 2 times or more, further preferably 2.5 times or more, and particularly preferably 3 times or more the friction force at a frequency of 5Hz of the pressure-sensitive adhesive layer before photocuring. The higher the ratio of the frictional force before and after photocuring, the higher the increase rate of the adhesive strength by photocuring tends to be. The friction force after photocuring is usually 20 times or less, preferably 10 times or less, the friction force before photocuring.

The frictional force at frequencies of 0.1Hz and 5Hz of the adhesive layer before and after photocuring was measured as follows: the measurement was carried out by conducting a rubbing measurement with a scanning width of 5 μm (reciprocating scanning 10 μm) in one direction in an FFM mode of a scanning probe microscope (AFM 5300E manufactured by Hitachi High-Tech Science Corporation) under the following conditions, and reading a differential voltage at a position of 3 μm from the left side of the measurement range.

(measurement conditions)

Cantilever: "Tap 300E-G" manufactured by BudgetSensors (equivalent spring constant 40N/m)

ADD value: 8.44V, DIF value: 0.4V, FFM value: 0V

Atmosphere: vacuum, room temperature

Scanning speed: 0.1Hz, 1Hz and 5Hz

Examples of the active rays that can be used for photocuring of the pressure-sensitive adhesive layer (2) include ultraviolet rays (UV), visible light, infrared rays, X-rays, α rays, β rays, and γ rays, and from the viewpoint of easy suppression of curing of the pressure-sensitive adhesive layer in a storage state and easy curing, UV. irradiation intensity and irradiation time of the active rays preferably may be appropriately set depending on the composition, thickness, and the like of the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive layer (2) is photocurable, and the timing of increasing the adhesive force by curing can be set arbitrarily. Therefore, the partial removal step can be performed at any timing during a period from when the pressure-sensitive adhesive sheet is attached to the adherend to when the pressure-sensitive adhesive is photocured, and therefore, the manufacturing cycle of the device manufacturing step can be flexibly coped with.

< Structure of adhesive sheet >

The thickness of the pressure-sensitive adhesive sheet used in the production method disclosed herein is not particularly limited, and may be, for example, about 3 μm to 11 mm. The thickness of the adhesive sheet is usually preferably 5 μm or more, and may be 10 μm or more, or 30 μm or more, from the viewpoint of handling property of the adhesive sheet and the like. From the viewpoint of workability of peeling off the second region in the partial removal step, and the like, in some embodiments, an adhesive sheet having a thickness of 50 μm or more, 70 μm or more, or 90 μm or more may be preferably used. The thickness of the adhesive sheet may be, for example, 1000 μm or less, 600 μm or less, 350 μm or less, 200 μm or less, or 150 μm or less from the viewpoints of cutting workability in the dicing step, peeling workability of the second region in the partial removal step, and the like.

The thickness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet including the base layer and the pressure-sensitive adhesive layer is not particularly limited, and may be, for example, about 1 μm to 1000 μm. In some embodiments, the thickness of the pressure-sensitive adhesive layer may be, for example, 3 μm or more, or 5 μm or more, or 8 μm or more, or 10 μm or more, or 13 μm or more, or 20 μm or more, or more than 20 μm. By increasing the thickness of the pressure-sensitive adhesive layer, a laminate in which the pressure-sensitive adhesive sheet is more firmly bonded to an adherend tends to be obtained. On the other hand, if the thickness of the pressure-sensitive adhesive layer is too large, workability in the partial removal step (for example, separability between the first region and the second region) may be reduced due to blocking of the pressure-sensitive adhesive in the first region and the pressure-sensitive adhesive in the second region. From this viewpoint, the thickness of the pressure-sensitive adhesive layer may be, for example, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 70 μm or less, 50 μm or less, 40 μm or less, or 30 μm or less.

The adhesive sheet comprising a base layer and an adhesive layer is not particularly limited in thickness of the base layer, and may be, for example, about 2 μm to 10 mm. In some embodiments, the thickness of the base material layer may be, for example, 5 μm or more, or 10 μm or more, or 25 μm or more, or 35 μm or more, or 50 μm or more, or 60 μm or more, from the viewpoint of handleability of the adhesive sheet and prevention of breakage of the second region in the partial removal step. In some embodiments, the thickness of the base material layer may be, for example, 1000 μm or less, 500 μm or less, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, or 90 μm or less, from the viewpoint of cutting workability in the dicing step.

The adhesive sheet used in the production method disclosed herein can be suitably implemented such that the thickness Ts of the base layer is larger than the thickness Ta of the adhesive layer. That is, it is preferable that Ts/Ta is greater than 1. Although not particularly limited, Ts/Ta may be, for example, 1.1 or more, 1.2 or more, 1.5 or more, 2 or more, or 2.5 or more. Further, Ts/Ta may be, for example, 50 or less, 20 or less, 10 or less, or 7 or less. By using a pressure-sensitive adhesive sheet having a configuration that satisfies any of the upper limit values and/or any of the lower limit values, it is possible to balance the good peeling workability in the partial removal step and the strong adhesiveness of the pressure-sensitive adhesive sheet to the adherend in the finally obtained laminate.

In some embodiments, the adhesive sheet used in the pasting step may have an area of 2500cm, for example²The length of the short side may be 50cm or more. In the case of using such a large adhesive sheet, it is particularly significant to adopt the manufacturing method disclosed herein. By using the pressure-sensitive adhesive sheet, for example, one or two or more effects of improvement in positional accuracy, improvement in shape accuracy, improvement in productivity, and the like tend to be exhibited appropriately. Further, according to the production method disclosed herein, since the partial removal step of removing the second region of the pressure-sensitive adhesive sheet by peeling is performed before the adhesive force of the pressure-sensitive adhesive sheet to the adherend exceeds 2N/25mm, the second region can be easily removed even in the case of a large pressure-sensitive adhesive sheet as described above. The adhesive sheet has an area of 3600cm²Above, more preferably 4900cm²In the above-described manner, a further higher effect can be exhibited when the length of the short side is 60cm or more, and more preferably 70cm or more.

< use >)

By the method disclosed herein, a laminate in which a pattern formed from a pressure-sensitive adhesive sheet is accurately formed on an adherend and which has excellent durability can be efficiently produced. Taking advantage of this advantage, the method disclosed herein can be preferably used for the production of a laminate in which a part of an adherend such as an exterior material for vehicles, an interior material, an exterior material for buildings, a building material such as an interior material, a window glass, a signboard, a sign, a home appliance product, an optical product, an electronic product, or a component thereof is covered with a pattern of a pressure-sensitive adhesive sheet as the adherend. The laminate may be any of the various products described above or constituent members thereof. The pressure-sensitive adhesive sheet is included in various products as a constituent element of the laminate, and contributes to imparting functions such as decoration, display, protection, reinforcement, impact relaxation, relaxation of stress concentration, shape maintenance, shape recovery, and the like to an adherend included in the laminate, or a product including the laminate, or a member thereof. The method disclosed herein can be preferably used for manufacturing an FPC provided with a thin film coverlay, for example.

Further, as for optical members used in optical products and electronic members used in electronic products, high integration, reduction in size and weight, and thinning have been advanced, and a plurality of thin optical members/electronic members having different linear expansion coefficients and thicknesses can be laminated. By using such a member as an adherend and forming a laminate in which the member is partially covered with an adhesive sheet by the method disclosed herein, appropriate rigidity can be imparted to the optical member/electronic member. This can suppress curling and bending of the product after the manufacturing process and/or the product after the manufacturing process, which are caused by stress that may occur between the plurality of members having different linear expansion coefficients and thicknesses.

In addition, in the manufacturing process of the optical product/electronic product, when the thin optical member/electronic member is subjected to shape processing such as cutting processing, the pressure-sensitive adhesive sheet is used as a reinforcing member by forming a laminate in which the member (adherend) is partially covered with the pressure-sensitive adhesive sheet, so that the local stress concentration on the optical member/electronic member accompanying the processing of the laminate can be alleviated, and the risk of cracking, breaking, peeling of the laminate member, and the like can be reduced. When the optical member/electronic member is treated by attaching the reinforcing member thereto, it is also helpful to alleviate local stress concentration in transportation, lamination, rotation, and the like of the member, and to suppress bending, and the like of the member due to its own weight.

Further, at the stage of using a device such as an optical product or an electronic product including a laminate in which an adherend is partially covered with a pattern of the adhesive sheet in the market by a consumer, when unintended stress is applied to the device at the time of dropping, placing under a heavy object, colliding with a flying object, or the like, the adhesive sheet contained in the device functions as a reinforcing member, and stress applied to the device can be relaxed, and durability can be improved.

The method disclosed herein can be preferably used for manufacturing a laminate in which constituent members of various portable devices (portable electronic devices), for example, are used as an adherend and the members are partially covered with a pattern of an adhesive sheet. Here, "portable" is insufficient if it is portable, and means portability at a level at which an individual (a standard adult) can be relatively easily carried. Examples of the portable device include a mobile phone, a smart phone, a tablet computer, a notebook computer, various wearable devices, a digital camera, a digital video camera, an audio device (such as a portable music player and an IC recorder), a calculator (such as an electronic calculator), a portable game machine, an electronic dictionary, an electronic manual, an electronic book, an in-vehicle information device, a portable electronic device such as a portable radio, a portable television, a portable printer, a portable scanner, and a portable modulator, a mechanical watch, a pocket watch, a flashlight, a small mirror with a handle, and the like. Examples of the member constituting the portable electronic device include an optical film, a display panel, and the like used for an image display device such as a thin-layer display such as a liquid crystal display and a thin-film display. The method disclosed herein can also be preferably used for the production of a laminate in which various members in automobiles, home electric appliances, and the like are used as adherends and the members are partially covered with a pattern of a pressure-sensitive adhesive sheet.

Examples

The following description will be made of several embodiments of the present invention, but the present invention is not intended to be limited to the specific embodiments shown. In the following description, "part" and "%" are based on weight unless otherwise specified.

(preparation of Polymer A1)

A reaction vessel equipped with a stirring blade, a thermometer, a nitrogen inlet tube, and a condenser was charged with 63 parts of 2-ethylhexyl acrylate (2EHA), 15 parts of N-vinylpyrrolidone (NVP), 9 parts of Methyl Methacrylate (MMA), 13 parts of 2-hydroxyethyl acrylate (HEA), and 200 parts of ethyl acetate as a polymerization solvent, and after stirring at 60 ℃ for 2 hours under a nitrogen atmosphere, 0.2 part of AIBN as a thermal initiator was charged, and a reaction was carried out at 60 ℃ for 6 hours to obtain a solution of polymer a 1. The Mw of this polymer A1 was 110 ten thousand.

(preparation of Polymer A2)

Solution polymerization was carried out in the same manner as in the synthesis of polymer a1 except that the composition of the monomers used was changed to 2EHA/HEA (weight ratio) 95/5, to obtain a solution of polymer a 2. The Mw of this polymer A2 was 90 ten thousand.

(preparation of Polymer A3)

In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen inlet tube and a condenser, 96.2 parts of 2EHA, 3.8 parts of HEA and 150 parts of ethyl acetate as a polymerization solvent were charged, and after stirring at 60 ℃ for 2 hours in a nitrogen atmosphere, 0.2 parts of AIBN as a thermal initiator was added to conduct a reaction at 60 ℃ for 6 hours, thereby obtaining a solution of polymer a3 (solid content 40%). The Mw of this polymer A3 was 54 million.

(preparation of Polymer B1)

In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen inlet tube and a condenser, 40 parts of MMA, 20 parts of n-Butyl Methacrylate (BMA), 20 parts of 2-ethylhexyl methacrylate (2EHMA), 9 parts of a polyorganosiloxane skeleton-containing methacrylate monomer (trade name: X-22-174ASX, manufactured by shin-Etsu chemical Co., Ltd.) having a functional group equivalent of 900g/mol, 11 parts of a polyorganosiloxane skeleton-containing methacrylate monomer (trade name: KF-2012, manufactured by shin-Etsu chemical Co., Ltd.) having a functional group equivalent of 4600g/mol, 100 parts of ethyl acetate, and 0.6 parts of thioglycerol as a chain transfer agent were charged, stirred at 70 ℃ for 1 hour under a nitrogen atmosphere, 0.2 parts of AIBN as a thermal initiator was charged, reacted at 70 ℃ for 3 hours, and then 0.1 parts by weight of AIBN was charged, followed by a reaction at 80 ℃ for 5 hours. Thus, a solution of polymer B1 containing a siloxane structure was obtained. The Mw of the polymer B1 was 20000.

The weight average molecular weight of each polymer was measured under the following conditions using a GPC apparatus (HLC-8220 GPC, manufactured by Tosoh corporation) and determined in terms of polystyrene.

Sample concentration: 0.2 wt% (tetrahydrofuran (THF) solution)

Sample injection amount: 10 μ l

Eluent: THF flow rate: 0.6 ml/min

Measurement temperature: 40 deg.C

Column:

a sample column; TSKguardcolumn SuperHZ-H (1 root) + TSKgel SuperHZM-H (2 roots)

A reference column; TSKgel SuperH-RC (1 root)

The detector: differential Refractometer (RI)

< production of adhesive sheet >

(adhesive sheet D1)

To the solution of the polymer A1, 2.5 parts of polymer B1 and 2.5 parts of an isocyanate-based crosslinking agent (trade name: TAKENATE D110N, trimethylolpropane xylylene diisocyanate, manufactured by mitsui chemical corporation) were added based on solid content to 1100 parts of the polymer a contained in the solution, and the mixture was uniformly mixed to prepare a pressure-sensitive adhesive composition C1.

A pressure-sensitive adhesive layer having a thickness of 25 μm was formed by directly applying a pressure-sensitive adhesive composition C1 to one surface of a PET film ("Lumiror S10" manufactured by Toray corporation) having a thickness of 75 μm and not subjected to surface treatment, and drying the film by heating at 110 ℃ for 2 minutes, and the release-treated surface of a release liner (MRQ 50T100 manufactured by Mitsubishi chemical corporation, a polyester film having one surface treated with a silicone-based release agent, and a film having a thickness of 50 μm) was bonded to the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer for protection. Thus, a pressure-sensitive adhesive sheet D1 was obtained, which had a pressure-sensitive adhesive layer on one surface of a base layer formed of a PET film having a thickness of 75 μm and had a surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer protected by a release liner.

(adhesive sheet D2)

To the solution of the polymer A1, 2.5 parts of an isocyanate-based crosslinking agent (trade name: TAKENATE D110N, trimethylolpropane xylylene diisocyanate, manufactured by Mitsui chemical Co., Ltd.), 30 parts of a light curing agent (trade name: A-200, polyethylene glycol #200 diacrylate, functional group equivalent 154g/eq, manufactured by Nakamura chemical industries, Ltd.), and 0.1 part of a photoinitiator were added to 1100 parts of the polymer A contained in the solution, and the mixture was uniformly mixed to prepare an adhesive composition C2. As the photoinitiator, 1-hydroxycyclohexyl phenyl ketone ("Irgacure 184" by BASF) was used.

An adhesive layer having a thickness of 25 μm was formed by directly applying an adhesive composition C2 to one surface of a PET film (lumiror S10, manufactured by tokyo corporation) having a thickness of 75 μm and not subjected to surface treatment, using a fountain roll (fountain roll), and drying the adhesive composition by heating at 130 ℃ for 1 minute. A release-treated surface of a release liner (a PET film whose surface was treated with a silicone release agent, having a thickness of 25 μm) was bonded to the surface (pressure-sensitive adhesive surface) of the pressure-sensitive adhesive layer to protect the surface, and the pressure-sensitive adhesive layer was cured at 25 ℃ for 4 days in an atmosphere to crosslink the surface. Thus, a pressure-sensitive adhesive sheet D2 having a pressure-sensitive adhesive surface protected by a release liner was obtained.

(adhesive sheet D3)

To the solution of the polymer A2, 2.5 parts of an isocyanate-based crosslinking agent (trade name: TAKENATE D110N, trimethylolpropane xylylene diisocyanate, manufactured by Mitsui chemical Co., Ltd.) was added based on solid content to 2100 parts of the polymer A contained in the solution, followed by uniform mixing to prepare a pressure-sensitive adhesive composition C3. A pressure-sensitive adhesive sheet D3 was obtained in which the pressure-sensitive adhesive surface was protected by a release liner in the same manner as in the production of the pressure-sensitive adhesive sheet D1, except that the pressure-sensitive adhesive composition C3 was used instead of the pressure-sensitive adhesive composition C1.

(adhesive sheet D4)

Adhesive composition C4 was prepared in the same manner as for the preparation of adhesive composition C1, except that polymer B1 was not used. A pressure-sensitive adhesive sheet D4 was obtained in which the pressure-sensitive adhesive surface was protected by a release liner in the same manner as in the production of the pressure-sensitive adhesive sheet D1, except that the pressure-sensitive adhesive composition C4 was used instead of the pressure-sensitive adhesive composition C1.

(adhesive sheet D5)

To 100 parts of the polymer A3 contained in the above-mentioned polymer A3 solution, 2.5 parts of polymer B1 and 3.3 parts of an isocyanate-based crosslinking agent (trade name: Coronate L (75% ethyl acetate solution of trimethylolpropane/tolylene diisocyanate 3-mer adduct, manufactured by tokyo co.) were added on a solid basis) and mixed uniformly to prepare an adhesive composition C5. instead of the adhesive composition C1, and an adhesive composition C5 was used, except that an adhesive sheet D5 having an adhesive surface protected by a release liner was obtained in the same manner as in the preparation of the adhesive sheet D1.

< measurement of adhesion to polyimide >

A polyimide film (Kapton 50EN, manufactured by Dupont, Toray) having a thickness of 12.5 μm was fixed to a glass plate via a double-sided pressure-sensitive adhesive tape (No. 531, manufactured by Nindon electric Co., Ltd.) to prepare a test piece for measuring a pressure-sensitive adhesive force. The pressure-sensitive adhesive sheets D1 to D4 and D5 were cut into a long strip of 25mm in width to prepare measurement samples.

The adhesive surface of the sample for measurement was brought into pressure contact with the test piece by reciprocating a 2kg roller 1 time under a standard atmosphere of 23 ℃ and 50% RH. After being left in the standard environment for 30 minutes, peel strength (initial adhesion) B was measured under conditions of a peel angle of 180 degrees and a tensile rate of 300 mm/minute based on JIS Z0237 using a tensile tester ("TCM-1 kNB" manufactured by Minebea corporation)₀[N/25mm]。

In addition, at initial adhesion B₀In the measurement of (3), the time for which the sample for measurement is left in the standard environment after being pressure-bonded to the test piece is changed to 12 hours and 24 hours. Other initial adhesion to B₀Likewise, the adhesion [ N ] is determined after 12 hours at room temperature25mm]And adhesion after 24 hours at room temperature [ N/25mm ]]。

Further, the initial adhesive force B₀The sample for measurement was pressure-bonded to the test piece in the same manner as in the above measurement, and after the test piece was held for about 4 weeks under a fluorescent lamp at room temperature (here, about 25 ℃ C.), the initial adhesive force B was measured₀Measurement of (2) peel strength (adhesion after 4 weeks) [ N/25mm ] was measured in the same manner as described above]。

Further, the initial adhesive force B was measured with respect to the samples for measurement made from the adhesive sheets D1 and D5₀The test piece was similarly pressed and left in the above standard environment for 30 minutes, and then heated at 80 ℃ for 5 minutes. After further leaving in the above-mentioned standard environment for 30 minutes, the peel strength (adhesion after heating) [ N/25mm ] was measured under the conditions of a peel angle of 180 degrees and a drawing speed of 300 mm/minute]As a result, the adhesive sheet D1 was 13.94N/25mm, and the adhesive sheet D5 was 5.45N/25 mm.

Further, the initial adhesive force B was brought into contact with a sample for measurement made of an adhesive sheet D2₀The measurement was carried out by pressing the test piece in the same manner, and after leaving the test piece under the standard conditions for 30 minutes, Unifield manufactured by USHIO INC. was used so as to be 2000mJ/cm²The ultraviolet ray having a main wavelength of about 365nm was irradiated. After further leaving in the standard environment for 30 minutes, the peel strength (adhesion after UV irradiation) [ N/25mm ] was measured under the conditions of a peel angle of 180 degrees and a stretching speed of 300 mm/minute]As a result, it was 19.84N/25 mm.

< production of laminate >

Production example 1

The adhesive sheet D1 was cut into a size of 25mm in width and 100mm in length to prepare an adhesive sheet for laminate production. A polyimide film (manufactured by Tolyo DuPont, Inc.; Kapton 50 EN) having a thickness of 12.5 μm, a width of 30mm and a length of 120mm was prepared as an adherend.

The center of the adherend is aligned with the center of the pressure-sensitive adhesive sheet, and the pressure-sensitive adhesive sheet is adhered to the adherend by a hand roller (adhering step).

After the adhesive sheet is attached to the adherend and before the partial removal step described below, a dicing step is performed. In the width center of the pressure-sensitive adhesive sheet in the pressure-sensitive adhesive sheet/adherend laminate obtained, a second region having a width of 2mm and a length of 100mm extending linearly from one end to the other end in the longitudinal direction of the pressure-sensitive adhesive sheet was set, and laser light was irradiated from the pressure-sensitive adhesive sheet surface side along the boundary (two straight lines) between the second region and the first regions on both sides thereof, thereby performing cutting processing for cutting only the pressure-sensitive adhesive sheet D1. The cutting was carried out under the following conditions using a laser cutting device "Spirit, model number SI-30V" manufactured by GCC corporation.

Speed (Speed): 9.0 percent

Power (Power): 10.0 percent

DPI：500

PPI：400

After about 12 hours from the time when the adhesive sheet was attached to the adherend, the partial removal step was performed. Specifically, one end of the second region was peeled off from the adherend, clamped by a jig of a tensile testing machine, and stretched in the longitudinal direction of the pressure-sensitive adhesive sheet under conditions of a peeling angle of 180 degrees and a stretching speed of 300 mm/min, thereby peeling off and removing a slit-like second region having a width of 2mm from the adherend.

Then, the above-mentioned heating (80 ℃ C., 5 minutes) was performed as a stimulus for increasing the adhesive strength (adhesive strength increasing step), thereby producing a laminate of the object, that is, a laminate having a structure in which the adherend is covered with the patterned adhesive sheet. Table 1 shows the value of the adhesive strength of the adhesive sheet D1 after 12 hours at room temperature as the adhesive strength in the partial removal step of production example 1, and the value of the adhesive strength of the adhesive sheet D1 after heating as the adhesive strength of the laminate.

Production example 2

Instead of the pressure-sensitive adhesive sheet D1, a pressure-sensitive adhesive sheet D2 was used, and the stimulus applied in the pressure-sensitive adhesive strength-increasing step was changed from heating to the above-mentioned UV irradiation (main wavelength: 365nm, light amount: 2000 mJ/cm)²) Except for this, a laminate was produced in the same manner as in production example 1. In table 1, the value of the adhesive force of the adhesive sheet D2 after 12 hours at room temperature is described as the adhesive force in the partial removal step of production example 2, and the adhesive force of the laminate is described as the adhesive force of the laminateThe adhesive sheet D2 was loaded with the value of the adhesive force after UV irradiation.

Production examples 3 and 4

The pressure-sensitive adhesive sheets shown in table 1 were used, and were left in the standard environment described above instead of being subjected to any of the above-described heating and UV irradiation after the dicing step until the elapsed time from the attachment of the pressure-sensitive adhesive sheet to the adherend became 24 hours. Except for this, a laminate was produced in the same manner as in production example 1. In table 1, the values of the adhesive strength of each adhesive sheet after 12 hours at room temperature are described as the adhesive strength in the partial removal step of production examples 3 and 4, and the values of the adhesive strength of each adhesive sheet after 24 hours at room temperature are described as the adhesive strength of the laminate.

Production example 5

In production example 1, after about 11 hours from the time when the adhesive sheet D1 was adhered to the adherend, the above-described heating (80 ℃ c, 5 minutes) was performed, and then, the sheet was kept at room temperature until the elapsed time from the time when the adhesive sheet D1 was adhered to the adherend became about 12 hours, and then, the partial removal step was performed. Except for this, a laminate was produced in the same manner as in production example 1. Table 1 shows the value of the adhesive force after heating of the adhesive sheet D2 as the adhesive force in the partial removal step of production example 5.

Production examples 6 and 7

The pressure-sensitive adhesive sheets D1 and D2 were adhered to an adherend in the same manner as in production example 1, left under a fluorescent lamp for about 24 hours in a room maintained in the standard environment, and then subjected to the cutting step and the partial removal step in the same manner. Thereafter, the self-adhesive sheets D1 and D2 were held under a fluorescent lamp in a room of the standard environment until the elapsed time from the attachment of the sheets to an adherend became 4 weeks, thereby obtaining laminates of production examples 6 and 7. In table 1, the values of the adhesive strength of each adhesive sheet after 24 hours at room temperature are described as the adhesive strength in the partial removal step of production examples 6 and 7, and the values of the adhesive strength of each adhesive sheet after 4 weeks are described as the adhesive strength of the laminate.

Production example 8

A laminate was produced in the same manner as in production example 1, except that an adhesive sheet D5 was used instead of the adhesive sheet D1. Table 1 shows the value of the adhesive strength of the adhesive sheet D5 after 12 hours at room temperature as the adhesive strength in the partial removal step of production example 8, and the value of the adhesive strength of the adhesive sheet D5 after heating as the adhesive strength of the laminate.

(evaluation of slit portion removability)

In the partial removal step of each production example, the case where deformation such as elongation of the adherend was not observed when the second region was peeled from the adherend was evaluated as "G" (good pattern processability), and the case where deformation was observed was evaluated as "P" (poor pattern processability). The results are shown in Table 1.

In production examples 4 and 5, the second region was not appropriately peeled off, and the following durability test was not performed. In addition, in any of production examples 1 to 3 and 6, 7, and 8, no adhesive residue on the adherend or contamination of the adherend was observed at the time of peeling of the second region.

(durability test)

The laminates obtained in production examples 1 to 3 and 6, 7 and 8 were subjected to a durability test under conditions of a stretching speed of 30rpm, a bending radius of 3mm, and a number of stretching times of 100 using a planar body no-load U-shaped stretching tester "DLDM 111 LH" manufactured by YUASA SYSTEM co., ltd.

Specifically, as shown in fig. 6, after both end portions x, y of the sample 60 were fixed to the grip portions 61, 62 of the testing machine with double-sided tapes (not shown), the sample 60 was repeatedly stretched and contracted in a U-shape bent from a flat state with the adhesive sheet side as the inside to a bending radius of 3mm under the above-described conditions. When the sample 60 is bent, both end portions x, y of the sample 60 are brought into contact by the operation of the clamp, and the rest of the sample 60 is clamped from both outer sides without load by the plate portions 63, 64 provided separately.

The state of the sample after 100 times of expansion and contraction was visually observed, and the case where no floating was observed between the pressure-sensitive adhesive sheet and the adherend was evaluated as "G" (good durability), and the case where floating was observed was evaluated as "P" (poor durability). The results are shown in Table 1.

[ TABLE 1 ]

TABLE 1

As shown in table 1, in production examples 1, 2,4 to 7, and 8 for the production of laminates having a bonding force of 5N/25mm, with respect to production examples 1, 2, 6, 7, and 8 in which the partial removal step was performed before the bonding force exceeded 2N/25mm, the releasability of the second region in the partial removal step was good, and the produced laminates exhibited good durability. Particularly good results were obtained in production examples 1, 2, 6, and 7, in which laminates were produced using adhesive sheets D1 and D2 each having an adhesive layer containing polymer a1 copolymerized with an N-vinyl cyclic amide. In contrast, the laminate obtained in production example 3 had low durability, and the releasability of the second region in the partial removal step was difficult in production examples 4 and 5.

While specific examples of the present invention have been described in detail, they are merely illustrative and do not limit the scope of the claims. The techniques described in the claims include various modifications and changes of the specific examples illustrated above.

Note that the matters disclosed in the present specification include the following.

(1) A method for producing a laminate comprising an adherend and a pressure-sensitive adhesive sheet covering a part of the adherend, wherein the pressure-sensitive adhesive sheet has a pressure-sensitive adhesive strength to the adherend of 5N/25mm or more, the method comprising the steps of:

a bonding step of bonding a pressure-sensitive adhesive sheet including a base material layer and a pressure-sensitive adhesive layer laminated on at least the adherend-side surface of the base material layer to the adherend;

a dicing step of performing cutting processing at a boundary between a first region of the adhesive sheet and a second region of the adhesive sheet; and

a partial removal step of leaving the first region on the adherend and peeling and removing the second region from the adherend,

here, the partial removal step is performed before the adhesive strength of the adhesive sheet to the adherend exceeds 2N/25 mm.

(2) The method for producing a laminate according to the item (1), wherein the adhesive sheet used is an adhesive sheet having an adhesive force of 2N/25mm or less after 24 hours at 23 ℃ after being bonded to polyimide.

(3) The method of producing a laminate according to the above (1) or (2), wherein a heat treatment is performed after the partial removal step so that the adhesive force of the first region to the adherend becomes 5N/25mm or more.

(4) The method for producing a laminate according to the item (3), wherein the pressure-sensitive adhesive layer includes: a polymer A having a glass transition temperature of less than 0 ℃ and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer.

(5) The method of producing a laminate according to the above (1) or (2), wherein an ultraviolet irradiation treatment is performed after the partial removal step so that the adhesive force of the first region to the adherend becomes 5N/25mm or more.

(6) The method for producing a laminate according to the item (5), wherein the adhesive layer is formed from a photocurable composition containing a base polymer and a photocurable agent,

the light curing agent is multifunctional (methyl) acrylate,

the content of the light curing agent is 1 part by weight or more and 50 parts by weight or less with respect to 100 parts by weight of the base polymer.

(7) The method for producing a laminate according to the above (1) or (2), wherein after the partial removal step, the laminate is stored at room temperature until the adhesive force of the first region to the adherend becomes 5N/25mm or more.

(8) The laminate production method according to any one of (1) to (7), wherein the thickness of the pressure-sensitive adhesive sheet is 30 μm or more, and the thickness Ts of the base layer is 2 times or more the thickness Ta of the pressure-sensitive adhesive layer.

(9) The laminate manufacturing method according to any one of the above (1) to (8), wherein the second region is set such that at least one end of the second region reaches an end of the adhesive sheet.

(10) The method of manufacturing a laminate according to the item (9), wherein the second region has a shape in which one end reaching the end of the adhesive sheet is widened toward the end of the adhesive sheet.

(11) The method for producing a laminate according to any one of the above (1) to (10), wherein the adhesive sheet used in the pasting step has an area of 2500cm²And the length of the short side is more than 50 cm.

(12) The method for producing a laminate according to any one of the above (1) to (11), wherein a pressure-sensitive adhesive sheet and an adherend comprising a plurality of cells corresponding to the laminate are used as the pressure-sensitive adhesive sheet and the adherend used in the sticking step,

the step to be performed after the adhering step further includes a dividing step of dividing the pressure-sensitive adhesive sheet and the adherend into the units.

(13) A laminate manufacturing apparatus for carrying out the manufacturing method according to any one of (1) to (12) above, comprising:

a sticking mechanism for sticking the adhesive sheet,

A cutting mechanism for cutting the adhesive sheet, and

and a peeling mechanism for peeling the second region of the adhesive sheet.

Description of the reference numerals

1 laminated body

10 adherend

10A surface

20 adhesive sheet

21 first region

21A, 21B adhesive sheet

22 second region

202 base material layer

204 adhesive layer

50 laminated body manufacturing device

51 pasting mechanism

52 cutting mechanism

53 peeling mechanism

Claims (10)

1. A method for producing a laminate comprising an adherend and a pressure-sensitive adhesive sheet covering a part of the adherend, the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive strength to the adherend of 5N/25mm or more, the method comprising the following steps in this order:

a bonding step of bonding a pressure-sensitive adhesive sheet, which includes a base material layer and a pressure-sensitive adhesive layer laminated on at least the adherend-side surface of the base material layer, to the adherend;

a dicing step of performing cutting processing at a boundary between a first region of the adhesive sheet and a second region of the adhesive sheet; and

a partial removal step of leaving the first region on the adherend and peeling and removing the second region from the adherend,

here, the adhesive layer includes: a polymer A having a glass transition temperature of less than 0 ℃ and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer,

the monomer component constituting the polymer A contains an N-vinyl cyclic amide,

the partial removal step is performed before the adhesive force of the adhesive sheet to the adherend exceeds 2N/25mm,

and performing a heat treatment after the partial removal step so that the adhesive force of the first region to the adherend is 5N/25mm or more.

2. The method for producing a laminate according to claim 1, wherein the monomer component constituting the polymer A further contains a hydroxyl group-containing monomer.

3. A method for producing a laminate comprising an adherend and a pressure-sensitive adhesive sheet covering a part of the adherend, the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive strength to the adherend of 5N/25mm or more, the method comprising the following steps in this order:

a bonding step of bonding a pressure-sensitive adhesive sheet, which includes a base material layer and a pressure-sensitive adhesive layer laminated on at least the adherend-side surface of the base material layer, to the adherend;

a dicing step of performing cutting processing at a boundary between a first region of the adhesive sheet and a second region of the adhesive sheet; and

a partial removal step of leaving the first region on the adherend and peeling and removing the second region from the adherend,

here, the adhesive layer includes: a polymer A having a glass transition temperature of less than 0 ℃ and a polymer B which is a copolymer of a monomer having a polyorganosiloxane skeleton and a (meth) acrylic monomer,

the monomer component constituting the polymer A contains an N-vinyl cyclic amide,

the partial removal step is performed before the adhesive force of the adhesive sheet to the adherend exceeds 2N/25mm,

after the partial removal step, the sheet is stored at normal temperature until the adhesive strength of the first region to the adherend becomes 5N/25mm or more.

4. The method for producing a laminate according to any one of claims 1 to 3, wherein the adhesive sheet has an adhesive force of 2N/25mm or less after 24 hours at 23 ℃ after being bonded to polyimide.

5. The laminate manufacturing method according to any one of claims 1 to 4, wherein the thickness of the adhesive sheet is 30 μm or more, and the thickness Ts of the base material layer is 2 times or more the thickness Ta of the adhesive layer.

6. The laminate manufacturing method according to any one of claims 1 to 5, wherein the second region is set such that at least one end of the second region reaches an end of the adhesive sheet.

7. The laminate manufacturing method according to claim 6, wherein the second region has a shape in which one end reaching the end of the adhesive sheet widens toward the end of the adhesive sheet.

8. The method for producing a laminate according to any one of claims 1 to 7, wherein the adhesive sheet used in the pasting step has an area of 2500cm²And the length of the short side is more than 50 cm.

9. The method for producing a laminate according to any one of claims 1 to 8, wherein a pressure-sensitive adhesive sheet and an adherend comprising a plurality of cells corresponding to the laminate are used as the pressure-sensitive adhesive sheet and the adherend used in the sticking step,

the step performed after the attaching step further includes a dividing step of dividing the pressure-sensitive adhesive sheet and the adherend into the units.

10. A laminate manufacturing apparatus for carrying out the manufacturing method according to any one of claims 1 to 9, comprising:

a sticking mechanism for sticking the adhesive sheet,

A cutting mechanism for cutting the adhesive sheet, and

a peeling mechanism that peels off the second region of the adhesive sheet.

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