JP5856867B2 - Pressure-sensitive adhesive sheet, method of using pressure-sensitive adhesive sheet, and method of manufacturing pressure-sensitive adhesive sheet - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive sheet, a method for using a pressure-sensitive adhesive sheet, and a method for producing a pressure-sensitive adhesive sheet. More specifically, it is a high-thickness pressure-sensitive adhesive sheet sandwiched between two release sheets having different peeling forces, having specific properties, and crying apart (at the time of peeling, only one release sheet cannot be peeled off, both Phenomenon in which the pressure-sensitive adhesive layer is stretched between release sheets) and the pressure-sensitive adhesive layer is not easily broken when the pressure-sensitive adhesive layer is punched (so-called glue scraping failure). The present invention relates to an effective method for producing a sheet and a method for using the pressure-sensitive adhesive sheet.

  The capacitive touch panel has a laminated structure of transparent base materials. In the laminated structure, a glass plate is used as a member close to the operation side from the viewpoint of design. This glass plate is frame-shaped decoratively printed to give the effect of concealing the electrodes inside the touch panel. Since this frame-like printing has a level difference, when it is laminated with a low-thickness pressure-sensitive adhesive layer or the like, followability becomes insufficient, and there is a concern that bubbles may be mixed. Therefore, a thick film adhesive layer is used for this bonding. When the adhesive is used in a thick film, it is generally used in a sheet state having excellent handling properties because there is a concern about yield reduction due to handling during the process.

  In order to improve workability, the shape of the release sheet of the adhesive sheet (light release sheet to be peeled first) sandwiched between two release sheets with different release forces is generally the adhesive layer that is the starting point of release. A release sheet having a portion (hereinafter also referred to as a “margin portion”) that does not exist is used. When the release sheet is peeled off, the blank portion becomes the starting point of peeling, but it has been a problem that tearing occurs. As described above, the pressure-sensitive adhesive sheet provided with the starting point of peeling is generally produced continuously by a roll-to-roll method or the like, and finally produced by cutting it. The number of pressure-sensitive adhesive sheets that can be taken per roll In order to increase the area, the area of the blank portion, which is generally the starting point of peeling of the pressure-sensitive adhesive sheet, is reduced. For this reason, the rigidity of the film contributes, and the peeling angle is small. In general, it is known that the peel force depends on the peel angle, and when the peel angle is small, the peel force becomes close to surface peeling and the peel force increases. Conventionally, as a countermeasure against crying separation, a peeling sheet having a large peeling force is used on the heavy peeling side, but conversely, the peeling force is too large to peel off the heavy peeling sheet.

By the way, a pressure-sensitive adhesive sheet, which has been widely used so far, is prepared by sticking a release agent layer of a release sheet in which a release agent layer is formed only on one side (adhesive layer side) of the release sheet substrate to the adhesive layer. Then, after die cutting, the residue may be raised to form a laminate. In this case, the adhesive protrudes from the die-cut end face, adheres to the opposite side of the release sheet layer of the release sheet substrate, and the label is lifted, whereby the label is placed on the opposite side of the release sheet of the release sheet. The problem of moving and turning over occurred, which was a problem in terms of yield and productivity.
Further, even when the laminate is formed without raising the residue after die cutting, the adhesive protrudes from the end surface of the die cut, so that the label is lifted to the side opposite to the release agent layer of the release sheet substrate or to the residue portion.

Various proposals have been made to suppress the sticking out of the pressure-sensitive adhesive or to reduce the influence of the pressure-sensitive adhesive protruding.
For example, a method of preliminarily irradiating an ultraviolet-ray to the die-cut planned site in the pressure-sensitive adhesive sheet (see, for example, Patent Document 1), the pressure-sensitive adhesive has a tensile strength of 5 kg / cm ² or more, and the release agent has a tensile strength of 30 kg. / Cm ² or more pressure-sensitive adhesive sheet (see, for example, Patent Document 2), pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive component, an inorganic filler such as calcium carbonate or aluminum hydroxide, and a silane coupling agent (for example, Patent Document 3) For example).

Japanese Patent Laid-Open No. 9-207097 Japanese Patent Laid-Open No. 2000-1651 JP 2002-249734 A

Each of the pressure-sensitive adhesive sheets and the like proposed in Patent Document 1 has an effect of suppressing the sticking out of the pressure-sensitive adhesive, but it is not perfect and the operation is complicated and the productivity may be lowered.
Moreover, in the adhesive sheet etc. which are proposed by the said patent documents 2-3, it is necessary to adjust the physical property and component of an adhesive, and it cannot apply to an adhesive of what kind of use or physical property.
The present invention has been made under such circumstances, and it is difficult for tearing to occur without complicated operations, and the adhesive layer is ruptured when the adhesive layer is punched, that is, so-called glue. An object of the present invention is to provide a pressure-sensitive adhesive sheet that is less likely to cause dregs raising, an effective method for producing the pressure-sensitive adhesive sheet, and a method for using a pressure-sensitive adhesive.

As a result of intensive research to achieve the above object, the present inventors have focused on the area of the release sheet, which is the starting point of the release, and the film rigidity of the release sheet resulting from the thickness. The pressure-sensitive adhesive sheet having the above properties can be efficiently produced by finding a configuration of the pressure-sensitive adhesive sheet that is difficult to cause and is difficult to cause defective glue lifting when the pressure-sensitive adhesive layer is punched. I found out. Furthermore, it has been found that, as a method of using the pressure-sensitive adhesive, it is advantageous to peel at a certain range of angles when peeling the light release sheet of the pressure-sensitive adhesive sheet.
The present invention has been completed based on such findings.

That is, the present invention
[1] An adhesive sheet in which an adhesive layer is sandwiched between a light release sheet and a heavy release sheet, the interface between the light release sheet and the adhesive layer measured by the following measurement method (1) The peel force is 30 to 90 mN / 25 mm, the peel force at the interface between the heavy release sheet and the pressure-sensitive adhesive layer measured by the following measurement method (2) is 150 to 300 mN / 25 mm, and the pressure-sensitive adhesive layer The thickness is 75 to 500 μm,
The area of the light release sheet is larger than the area of the pressure-sensitive adhesive layer in contact with the light release sheet, and the distance from the end of the pressure-sensitive adhesive layer to the end of the light release sheet is at least partially 8 to 35 mm. A pressure-sensitive adhesive sheet,
Measurement method (1): For an adhesive sheet sample left for 168 hours under conditions of 23 ° C. and 50% RH, the adhesive sheet sample was cut into a width of 25 mm × a length of 200 mm in accordance with JIS Z 0237, and then peeled off. The peel side at the interface between the light release sheet and the pressure-sensitive adhesive layer is measured by fixing the sheet side to a stainless steel plate and pulling the light release sheet in a 180 ° direction at a speed of 300 mm / min using a tensile tester. .
Measurement method (2): The light release sheet was peeled from the pressure-sensitive adhesive sheet sample, and the pressure-sensitive adhesive layer exposed was attached to a stainless steel plate, and the heavy release sheet was rotated 180 ° at a speed of 300 mm / min using a tensile tester. The peel strength at the interface between the heavy release sheet and the pressure-sensitive adhesive layer is measured.
[2] The pressure-sensitive adhesive sheet according to the above [1], wherein the light release sheet has a thickness of 25 to 75 μm.
[3] The pressure-sensitive adhesive sheet according to the above [1] or [2], wherein the peel strength of the heavy release sheet is 2.5 times or more of the peel strength of the light release sheet,
[4] The pressure-sensitive adhesive sheet according to any one of the above [1] to [3], wherein the shape of the pressure-sensitive adhesive layer surface in contact with the light release sheet and the heavy release sheet is square.
[5] When the light release sheet of the pressure sensitive adhesive sheet according to any one of the above [1] to [4] is peeled, the pressure sensitive adhesive sheet is peeled at an angle of 90 to 180 °, and
[6] The method for producing a pressure-sensitive adhesive sheet according to any one of the above [1] to [4], comprising the following steps (a) to (d).
Step (a): Step of stacking a heavy release sheet, a pressure-sensitive adhesive layer having a thickness of 75 to 500 μm, and a protective film having a lower peel strength than that of the heavy release sheet to obtain a laminated sheet (A) Step (b): Lamination Step (c) of punching the pressure-sensitive adhesive layer and protective film of the sheet (A) into a predetermined shape to obtain a laminated sheet (B): a protective film of a portion other than the predetermined shape from the laminated sheet (B) And removing the pressure-sensitive adhesive layer in a portion other than the predetermined shape and the protective film in the predetermined shape portion, and a laminated sheet (C) provided with the pressure-sensitive adhesive layer on the heavy release sheet Step (d) of obtaining: The light release sheet of the laminated sheet (C) so that the distance from the end of the pressure-sensitive adhesive layer to the end of the light release sheet is at least partly 8 to 35 mm. Bonded to the adhesive layer and light release Over preparative and adhesive layer by the polymerization release sheet is intended to provide a process for obtaining a pressure-sensitive adhesive sheet formed by sandwiching.

  According to the present invention, the pressure-sensitive adhesive sheet is less prone to crying without causing complicated operations and is less likely to cause tearing of the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is punched, so-called poor glue lifting, An effective method for producing a pressure-sensitive adhesive sheet and a method for using the pressure-sensitive adhesive sheet can be provided.

It is a cross-sectional schematic diagram which shows a structure of an example of the adhesive sheet of this invention. It is a plane schematic diagram which shows an example of an adhesive layer and a light peeling sheet. It is a cross-sectional schematic diagram which shows the usage method of an example of the adhesive sheet of this invention. It is process explanatory drawing of an example in the manufacturing method of the adhesive sheet of this invention. It is a schematic diagram (perspective view) which shows an example of the adhesive sheet of this invention produced in the Example.

First, the pressure-sensitive adhesive sheet of the present invention will be described.
[Adhesive sheet]
FIG. 1 is a schematic cross-sectional view showing the structure of an example of the pressure-sensitive adhesive sheet of the present invention. The pressure-sensitive adhesive sheet of the present invention will be described with reference to FIG.
In the pressure-sensitive adhesive sheet 100 of the present invention, the light release sheet 2 and the pressure-sensitive adhesive layer 1a are measured by the following measurement method (1). The peel strength at the interface is 30 to 90 mN / 25 mm, and the peel force at the interface between the heavy release sheet 3 and the pressure-sensitive adhesive layer 1 a measured by the following measurement method (2) is 150 to 300 mN / 25 mm. The thickness of the adhesive layer is 75 to 500 μm, and the area of the light release sheet 2 is larger than the area of the pressure-sensitive adhesive layer 1a in contact with the light release sheet 2 and from the end of the pressure-sensitive adhesive layer 1a. The distance x to the end of the light release sheet 2 is at least partially 8 to 35 mm. In FIG. 1, 11 is an end portion of the pressure-sensitive adhesive layer 1 a, and 21 is an end portion of the light release sheet 2.

(Peeling sheet)
In the present invention, the peeling force of the light release sheet 2 and the peeling force of the heavy release sheet 3 are measured by the following measuring methods (1) and (2), respectively.
Measuring method (1): Peeling force of light release sheet 2 For an adhesive sheet sample left for 168 hours under conditions of 23 ° C. and 50% RH, the adhesive sheet sample was 25 mm wide × 200 mm long according to JIS Z 0237 After being cut into pieces, the heavy release sheet 3 side is fixed to a stainless steel plate, and the light release sheet 2 and the pressure-sensitive adhesive are pulled by pulling the light release sheet 2 in the 180 ° direction at a speed of 300 mm / min using a tensile tester. The peeling force at the interface with the layer 1a is measured.

Measurement method (2): Peeling force of heavy release sheet 3 The light release sheet was peeled off from the pressure sensitive adhesive sheet sample, and the pressure sensitive adhesive layer exposed was applied to a stainless steel plate. The peel force at the interface between the heavy release sheet 3 and the pressure-sensitive adhesive layer 1a is measured by pulling in the 180 ° direction at a speed of / min.

In the pressure-sensitive adhesive sheet of the present invention, the area of the light release sheet 2 is larger than the area of the pressure-sensitive adhesive layer 1a in contact with the light release sheet 2, and the light release sheet 2 has an area from the end 11 of the pressure-sensitive adhesive layer 1a. The distance x to the end portion 21 needs to be 8 to 35 mm at least in part. If this distance is less than 8 mm, when the light release sheet is captured and peeled with a finger, a sufficient peel angle (90 ° or more) cannot be obtained, and tearing is likely to occur. On the other hand, if it is longer than 35 mm, there is a risk that peeling will occur during handling. From such a viewpoint, the distance x is preferably 10 to 30 mm.
In the present invention, “the area of the light release sheet 2 is larger than the area of the pressure-sensitive adhesive layer 1 a in contact with the light release sheet 2” means that the entire circumference of the pressure-sensitive adhesive layer 1 a is the end of the light release sheet 2. The aspect provided in the inner side is said, FIG. 2 is a plane schematic diagram which shows the example.
In the present invention, “the distance x from the end of the pressure-sensitive adhesive layer 1a to the end of the light release sheet 2 is at least partly 8 to 35 mm” means, for example, the pressure-sensitive adhesive layer 1a and the light release When the sheet 2 has a square shape, the distance x from the end 11 of the pressure-sensitive adhesive layer 1a to the end 21 of the light release sheet 2 in FIG. 2 is 8 to 35 mm on at least one side.

  In the said adhesive sheet, the peeling force of the light peeling sheet 2 measured by the said measuring method (1) needs to be 30-90 mN / 25mm. If this peel force is less than 30 mN / 25 mm, it may be peeled off accidentally during handling, and if it is greater than 90 mN / 25 mm, crying is likely to occur. From such a viewpoint, the peeling force of the light release sheet 2 is preferably 40 to 80 mN / 25 mm.

  On the other hand, the peeling force of the heavy release sheet 3 measured by the measurement method (2) needs to be 150 to 300 mN / 25 mm. When the peeling force is less than 150 mN / 25 mm, a sufficient peeling force difference from the light release sheet 2 cannot be ensured, and tearing is likely to occur. Further, if the peeling force is larger than 300 mN / 25 mm, the cohesive force of the pressure-sensitive adhesive layer loses the peeling force from the heavy release sheet 3 when the pressure-sensitive adhesive layer is punched, and the pressure-sensitive adhesive layer is torn. In other words, there is a possibility that a so-called glue scraping failure may occur. From such a viewpoint, the peeling force of the heavy release sheet 3 is preferably 170 to 260 mN / 25 mm.

  In the pressure-sensitive adhesive sheet, from the viewpoint that crying separation hardly occurs, the peeling force of the heavy release sheet 3 is preferably 2.5 times or more, more preferably 3.0 times or more that of the light release sheet 2. Is more preferable.

The thickness of the light release sheet 2 in the pressure-sensitive adhesive sheet of the present invention is preferably 25 to 75 μm, and more preferably 25 to 50 μm. If this thickness is 25 μm or more, foreign matter of the light release sheet will be prevented from appearing on the surface and dents will be generated, and it will have a good appearance. On the other hand, if the thickness is 75 μm or less, the peeling sheet itself is not too rigid, and a sufficient peeling angle can be secured, so that it is difficult for tearing to occur.
The thickness of the heavy release sheet 3 in the pressure-sensitive adhesive sheet is not particularly limited, but is usually in the range of 38 to 100 μm.

  The light release sheet 2 and the heavy release sheet 3 used in the pressure-sensitive adhesive sheet of the present invention can be produced by providing a release agent layer on the substrate surface. As the release sheet substrate, polyethylene terephthalate, polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, polyvinyl chloride, vinyl chloride copolymer, polybutylene terephthalate, polyurethane, ethylene-vinyl acetate copolymer, ionomer resin, Resin films such as ethylene (meth) acrylic acid copolymer, polystyrene, polycarbonate, fluororesin, low density polyethylene, linear low density polyethylene, triacetyl cellulose, fine paper, coated paper, glassine paper, laminated paper, etc. It is done. Among these, a polyethylene terephthalate film that is inexpensive and firm is preferable.

Examples of the release agent constituting the release agent layer provided on the surface of the release sheet substrate include silicone resins, fluorine resins, and long chain alkyl group resins. Among these, inexpensive and stable A silicone-based resin capable of obtaining the desired performance is preferred. The thickness of the release agent layer is preferably 0.05 to 2.0 μm, and more preferably 0.1 to 1.5 μm.
The adjustment of the peeling force in the light release sheet and the heavy release sheet can be performed by selecting, for example, the type of release agent, the thickness of the release agent layer, the type and the thickness of the release sheet base material, and the like.

(Adhesive layer)
The pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet of the present invention is shown by 1a in FIG. 1 and needs to have a thickness of 75 to 500 μm. If the thickness is less than 75 μm, the volume of the pressure-sensitive adhesive layer to be deformed becomes small, and even if the present invention is not applied, peeling may be possible only by the difference in peeling force between the light release sheet and the heavy release sheet. . Moreover, when it exceeds 500 micrometers, the workability at the time of punching in the manufacturing method of the adhesive sheet mentioned later falls.
From the above viewpoint, the thickness of the pressure-sensitive adhesive layer is preferably 80 to 400 μm, more preferably 100 to 350 μm.
Moreover, the shape of an adhesive layer should just have a predetermined shape according to a use, and there is no restriction | limiting in particular. The “predetermined shape” may be, for example, a square such as a square, a rectangle, a trapezoid, or a rhombus, a triangle, a circle, an ellipse, a star, or the like, but may be a square such as a square or a rectangle. Is common.

  There is no restriction | limiting in particular as an adhesive which comprises the adhesive layer in the adhesive sheet of this invention, Various adhesives, for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a polyurethane adhesive, a polyester adhesive Among them, acrylic pressure-sensitive adhesives are preferably used from the viewpoints of weather resistance, pressure-sensitive adhesive performance, economy, and the like.

<Adhesive>
The acrylic pressure-sensitive adhesive suitable as the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer in the present invention preferably includes a (meth) acrylic acid ester-based copolymer as a resin component and a crosslinking agent.
This (meth) acrylic acid ester-based copolymer includes (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the ester moiety and a crosslinkable functional group-containing ethylenic monomer used as necessary. Preferred examples include monomers and copolymers with other monomers.

[(Meth) acrylic acid alkyl ester]
Examples of the alkyl group (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the ester moiety include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, and n-butyl. Examples include acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, n-hexyl acrylate, n-hexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate and stearyl methacrylate. These may be used individually by 1 type and may be used in combination of 2 or more type.

(Crosslinkable functional group-containing ethylenic monomer)
Examples of the crosslinkable functional group-containing ethylenic monomer used as necessary include ethylenic monomers having functional groups such as hydroxyl group, carboxyl group, amino group, substituted amino group, and epoxy group in the molecule. Yes, preferably a hydroxy group-containing ethylenically unsaturated compound or a carboxyl group-containing ethylenically unsaturated compound is used. Specific examples of such a crosslinkable functional group-containing ethylenic monomer include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate. Hydroxy group-containing acrylates such as 2-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, carboxyl group-containing ethylenic groups such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid Saturated compounds are mentioned. The crosslinkable functional group-containing ethylenic monomer may be used alone or in combination of two or more.

[Other monomers]
Other monomers used as necessary include (meth) acrylic acid esters having an alicyclic structure such as cyclohexyl acrylate and isobornyl acrylate; vinyl esters such as vinyl acetate and vinyl propionate; ethylene, Olefins such as propylene and isobutylene; Halogenated olefins such as vinyl chloride and vinylidene chloride; Styrene monomers such as styrene and α-methylstyrene; Diene monomers such as butadiene, isoprene and chloroprene; Acrylonitrile and methacrylate And nitrile monomers such as rhonitrile; N, N-dialkyl-substituted acrylamides such as N, N-dimethylacrylamide and N, N-dimethylmethacrylamide. These may be used individually by 1 type and may be used in combination of 2 or more type.

[Production of (meth) acrylic ester copolymer]
First, the (meth) acrylic acid alkyl ester described above, and the crosslinkable functional group-containing ethylenic monomer and other monomers used as necessary are used in a predetermined ratio, respectively, and are shared according to a conventionally known method. Polymerization is performed to produce a (meth) acrylate copolymer having a weight average molecular weight of preferably about 500,000 to 1,500,000, more preferably about 500,000 to 1,300,000.
In addition, the said weight average molecular weight is the value of standard polystyrene conversion measured by the gel permeation chromatography (GPC) method.

<Crosslinking agent>
Examples of the crosslinking agent contained in the pressure-sensitive adhesive include organic polyvalent isocyanate compounds, organic polyvalent epoxy compounds, organic polyvalent imine compounds, metal chelate compounds, and the like. Among these, an organic polyvalent isocyanate compound, an organic polyvalent epoxy compound, and a metal chelate compound are preferable from the viewpoints of increasing cohesive force and improving adhesive force, and availability.

Examples of organic polyvalent isocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4,4′-diisocyanate, diphenylmethane Examples include -2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and lysine isocyanate.
In addition, trimers of these polyvalent isocyanate compounds, terminal isocyanate urethane prepolymers obtained by reacting these polyvalent isocyanate compounds and polyol compounds, and the like can also be used.

  Examples of organic polyvalent epoxy compounds include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, 1,3-bis (N, N-diglycidylaminomethyl) toluene, N, N, N ′, N′-tetraglycidyl- Examples include 4,4-diaminodiphenylmethane.

  Examples of organic polyvalent imine compounds include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, tetramethylolmethane-tri- β-aziridinylpropionate, N, N′-toluene-2,4-bis (1-aziridinecarboxyamide) triethylenemelamine and the like can be mentioned.

  Examples of the metal chelate compound include coordination compounds of polyvalent metals such as aluminum chelate compounds such as trisethylacetoacetate aluminum, ethylacetoacetate aluminum diisopropylate, and trisacetylacetonatoaluminum.

In addition, you may use these crosslinking agents individually or in combination of 2 or more types.
The content of the crosslinking agent is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7 parts by mass, and still more preferably 0.1 to 100 parts by mass of the (meth) acrylic acid ester copolymer. 2 to 4 parts by mass. If it is 0.01 parts by mass or more, sufficient cohesive force of the adhesive to maintain the shape against the stress in the shear direction is obtained, and if it is 10 parts by mass or less, sufficient adhesive force is obtained.

<Preparation of adhesive>
The pressure-sensitive adhesive includes the above-mentioned (meth) acrylic acid ester copolymer, a crosslinking agent and other additives used as necessary, for example, tackifiers, pigments, dyes, antioxidants, ultraviolet absorbers and the like. It can be prepared by adding a suitable solvent to a concentration suitable for coating.

[Usage of adhesive sheet]
This invention also provides the usage method of the adhesive sheet characterized by peeling at the angle of 90-180 degrees, when peeling the light release sheet in the adhesive sheet of this invention mentioned above. If the distance x from the end portion 11 of the pressure-sensitive adhesive layer 1a to the end portion 21 of the light release sheet 2 in FIG. 1 is at least partially 8 to 35 mm, the light release sheet is peeled at an angle in the above range. Can suppress the occurrence of crying.
FIG. 3 is a schematic cross-sectional view showing an example of a method for using the pressure-sensitive adhesive sheet. In the present invention, “peeling at an angle of 90 to 180 °” means that the angle z formed by the peeling direction y of the light release sheet 2 and the upper surface of the pressure-sensitive adhesive layer 1a is 90 to 180 ° in FIG. It means that the light release sheet 2 is peeled off.

Next, the manufacturing method of the adhesive sheet of this invention is demonstrated.
[Method for producing adhesive sheet]
The manufacturing method of the adhesive sheet of this invention has the following process (a)-process (d), It is characterized by the above-mentioned.
Step (a): Step of stacking a heavy release sheet, a pressure-sensitive adhesive layer having a thickness of 75 to 500 μm, and a protective film having a lower peel strength than that of the heavy release sheet to obtain a laminated sheet (A) Step (b): Lamination Step (c) of punching the pressure-sensitive adhesive layer and protective film of the sheet (A) into a predetermined shape to obtain a laminated sheet (B): a protective film of a portion other than the predetermined shape from the laminated sheet (B) And removing the pressure-sensitive adhesive layer in a portion other than the predetermined shape and the protective film in the predetermined shape portion to obtain a laminated sheet (C) in which the pressure-sensitive adhesive layer is provided on the heavy release sheet. Step (d): Adhesion of the laminated sheet (C) so that the distance from the end of the pressure-sensitive adhesive layer to the end of the light-release sheet is at least partly 8 to 35 mm. The light release sheet 4 is a process explanatory diagram of an example in the method for producing a pressure-sensitive adhesive sheet of the present invention, and is a specific example of the production method. Will be described with reference to FIG.

(Process (a))
Step (a) is a step in which a heavy release sheet, a pressure-sensitive adhesive layer having a thickness of 75 to 500 μm, and a protective film having a lower peeling force than the heavy release sheet are sequentially laminated to obtain a laminated sheet (A).
First, a heavy release sheet 3 having a peel force measured by the above-described method of 150 to 300 mN / 25 mm is prepared [FIG. 4 (A)]. Next, after the pressure-sensitive adhesive coating liquid was applied and dried on the release-treated surface of the heavy release sheet 3 so that the thickness after drying was 75 to 500 μm, the pressure-sensitive adhesive layer 1 was formed [FIG. 4 (B)]. The protective film 4 having a lower peeling force than the heavy release sheet 3 is bonded onto the pressure sensitive adhesive layer 1 so that the release treatment surface is in contact with the pressure sensitive adhesive layer 1, and the heavy release sheet 3 and the pressure sensitive adhesive layer 1 are bonded. And the laminated sheet 200 (namely, laminated sheet (A)) by which the protective film 4 was laminated | stacked in order is obtained [FIG. 4 (C)].
As the protective film 4, the thing similar to the light peeling sheet 2 mentioned above can be used. In addition, after forming the said adhesive layer 1 on the protective film 4 in a process (a), it bonds so that the peeling process surface may contact | connect the adhesive layer 1, and the laminated sheet 200 is bonded. It can also be obtained.

(Process (b))
Step (b) is a step of punching the pressure-sensitive adhesive layer and protective film of the laminated sheet (A) into a predetermined shape to obtain a laminated sheet (B). By this step, a plurality of pressure-sensitive adhesive layers smaller than the area of the heavy release sheet can be formed on one heavy release sheet. This is advantageous when manufacturing continuously.
In the step (b), the laminated sheet 200 is punched into a predetermined shape, for example, at the position of the arrow 5 shown in FIG. That is, a laminated sheet (B)) is obtained [FIG. 4 (e)].

(Process (c))
In step (c), from the laminated sheet (B), a protective film of a portion other than the predetermined shape, an adhesive layer of a portion other than the predetermined shape, and a protective film of the predetermined shape portion. It is a process of removing and obtaining the lamination sheet (C) in which the said adhesive layer was provided on the said heavy release sheet.
In the step (c), the order of removing the protective film of the portion other than the predetermined shape, the adhesive layer of the portion other than the predetermined shape, and the protective film of the predetermined shape portion is particularly limited. No, a plurality of removal steps may be performed simultaneously.
For example, in the laminated sheet 300, the protective film 4b in a portion other than the predetermined shape shown in FIG. 4 (e) is removed, and then the pressure-sensitive adhesive layer 1b in a portion other than the predetermined shape is removed. By giving the process of removing the protective film 4a which has a shape, the laminated sheet 400 (namely, laminated sheet (C)) by which the adhesive layer 1a which has a predetermined shape is laminated | stacked on the heavy peeling sheet 3 is obtained. [Fig. 4 (f)].
Further, in the laminated sheet 300, a portion of the protective film 4b other than the predetermined shape shown in FIG. 4 (e) is removed, and then a sheet 8 having an adhesive layer 7 on the substrate 6 is prepared. A surface of the sheet 8 on the side of the pressure-sensitive adhesive layer 7 is pasted on the pressure-sensitive adhesive layer 1b other than the shape and the protective film 4a having a predetermined shape [FIG. 4 (e ')], and then peeled off. And the said lamination sheet 400 (namely, lamination sheet (C)) can also be obtained by performing the process of removing the adhesive layer 1b and the protective film 4a simultaneously [FIG. 4 (f)].

(Process (d))
In step (d), the light release sheet is adhered to the laminated sheet (C) so that the distance from the end of the pressure-sensitive adhesive layer to the end of the light release sheet is at least partly 8 to 35 mm. In this step, the pressure-sensitive adhesive layer is bonded to the adhesive layer, and the pressure-sensitive adhesive layer is sandwiched between the light release sheet and the heavy release sheet.
In the said process (d), the light peeling sheet 2 is bonded so that the peeling process surface may contact | connect the adhesive layer 1a in the said laminated sheet (C) 400 [FIG. 4 (G)]. The light release sheet 2 is the same as described above, and is bonded so that the distance from the end of the pressure-sensitive adhesive layer 1a to the end of the light release sheet 2 is at least partly 8 to 35 mm. The light release sheet may be bonded to the pressure-sensitive adhesive layer by using a labeling machine, and the light release sheet previously punched into a predetermined shape may be bonded to the pressure-sensitive adhesive layer. The release sheet may be bonded and only the light release sheet may be punched again.
4G is the same as FIG. 1 described above, and the distance x in FIG. 1 is 8 to 35 mm.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
In addition, while peeling force of the light release sheet and heavy release sheet used in each example was measured by the following method, crying separation was evaluated according to the following.

(1) Peeling force of light release sheet The adhesive sheet in a state before punching produced in each Example and each Comparative Example (which was allowed to stand for 168 hours at 23 ° C. and 50% RH) conforms to JIS Z 0237 Then, the pressure-sensitive adhesive sheet is cut into a width of 25 mm and a length of 200 mm, and the heavy release sheet is fixed to the stainless steel plate using a tensile tester (manufactured by Orientec Co., Ltd., product name “TENSILON UTM-4-100”). The peel force was determined by pulling the light release sheet in the 180 ° direction at a speed of 300 mm / min.

(2) Peeling force of heavy release sheet In the above (1), a polyethylene terephthalate film (product name “Lumirror T60 # 25”, thickness 25 μm, manufactured by Toray Industries, Inc.) is applied to the pressure-sensitive adhesive layer that is exposed by peeling the light release sheet. The polyethylene terephthalate film was fixed to a stainless steel plate, and the peeling force was determined by pulling the heavy release sheet in the 180 ° direction at a speed of 300 mm / min using a tensile tester (supra).

(3) Evaluation of crying separation When the light release sheet was peeled off, the presence or absence of crying separation at the heavy release sheet / adhesive layer interface was confirmed under the following conditions.
○: Confirmed 20 times and no crying separation occurred.
Δ: Confirmation 20 times and crying once.
X: Confirmed 20 times and crying occurs twice or more.

Preparation example (preparation of adhesive coating solution)
Acrylic copolymer (BA / AA) mass ratio of butyl acrylate (BA) and acrylic acid (AA) = 90:10, weight average molecular weight 600,000) 0.025 parts by mass of product name “TETRAD-C” (concentration 100%) manufactured by the company was mixed and diluted with methyl ethyl ketone to prepare a pressure-sensitive adhesive coating solution having a nonvolatile content concentration of 40% by mass.

Example 1
The adhesive coating solution obtained in the preparation example was applied to a heavy release sheet (product name “SP-PET753030”, manufactured by Lintec Corporation, thickness: 75 μm) so that the thickness after drying was 175 μm. A protective film (manufactured by Lintec Corporation, product name “SP-PET382120”, thickness: 38 μm) was bonded to the formed adhesive layer after drying in an oven to obtain an adhesive sheet. After leaving at room temperature for 1 week, the protective film and the pressure-sensitive adhesive layer were punched into a size of 60 mm long × 40 mm wide from the surface of the protective film (flat cutting method). Next, unnecessary portions of the protective film (portions other than the punched length of 60 mm × width of 40 mm) were removed, and unnecessary portions of the pressure-sensitive adhesive layer and the remaining protective film were further removed. After that, the labeling machine was used to peel the release surface of a light release sheet (product name “SP-PET382120”, thickness: 38 μm) manufactured by Lintec Co., Ltd.) that was punched into 90 mm (length) x 45 mm (width). The adhesive sheet of Example 1 was obtained by using and sticking to the adhesive layer. In FIG. 5, the schematic diagram (perspective view) of the adhesive sheet produced in this-application Example is shown. The broken line portion is the pressure-sensitive adhesive layer 1 a sandwiched between the light release sheet 2 and the heavy release sheet 3.
The light release sheet of this pressure-sensitive adhesive sheet was peeled off at an angle shown in Table 1, and crying separation was evaluated. The results and conditions are shown in Table 1.

Example 2
An adhesive sheet was prepared in the same manner as in Example 1 except that the light release sheet was changed to Lintec Corporation, product name “SP-PET502120”, thickness: 50 μm. The angle shown in Table 1 for the light release sheet And peeled off to evaluate crying. The results are shown in Table 1.

Example 3
An adhesive sheet was prepared in the same manner as in Example 1 except that the heavy release sheet was changed to Lintec Corporation, product name “SP-PET752150”, thickness: 75 μm, and the angle shown in Table 1 for the light release sheet. And peeled off to evaluate crying. The results are shown in Table 1.

Example 4
The light release sheet is 70 mm long x 40 mm wide, manufactured by Lintec Corporation, product name “SP-PET252120”, thickness: 25 μm, and the distance from the end of the adhesive sheet to the end of the light release sheet is 10 mm A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the light release sheet was peeled off at the angle shown in Table 1 and the crying separation was evaluated. The results are shown in Table 1.

Example 5
Except that the thickness of the pressure-sensitive adhesive layer was changed to 350 μm, a pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1, and the light release sheet was peeled off at an angle shown in Table 1 to evaluate crying separation. The results are shown in Table 1.

Example 6
The pressure-sensitive adhesive sheet was changed in the same manner as in Example 1 except that the thickness of the pressure-sensitive adhesive layer was changed to 80 μm, and the light release sheet was changed to product name “SP-PET 382120” and thickness: 38 μm, manufactured by Lintec Corporation. The light release sheet was prepared and peeled at the angle shown in Table 1 to evaluate crying separation. The results are shown in Table 1.

Comparative Example 1
Adhesion in the same manner as in Example 1 except that the size of the light release sheet was changed to 67 mm in length x 40 mm in width and the distance from the end of the adhesive sheet to the end of the light release sheet was changed to 7 mm. A sheet was prepared, and the light release sheet was peeled off at the angle shown in Table 1 to evaluate crying separation. The results are shown in Table 1.

Comparative Example 2
Adhesive in the same manner as in Example 2 except that the size of the light release sheet was changed to 67 mm in length x 40 mm in width and the distance from the end of the adhesive sheet to the end of the light release sheet was changed to 7 mm. A sheet was prepared, and the light release sheet was peeled off at the angle shown in Table 1 to evaluate crying separation. The results are shown in Table 1.

As can be seen from Table 1, each of the adhesive sheets obtained in Examples 1 to 6 has a crying evaluation of “◯”.
On the other hand, the pressure-sensitive adhesive sheets obtained in Comparative Examples 1 and 2 have a short length of 7 mm from the end portion to the end portion of the light release sheet, so that they are difficult to capture with fingers and have a peeling angle of 90 ° or more. The crying separation evaluation is “x” for both.

The pressure-sensitive adhesive sheet of the present invention is characterized in that it is difficult for tearing to occur without performing complicated operations, and that the pressure-sensitive adhesive layer is not easily broken when the pressure-sensitive adhesive layer is punched out, so-called defective glue lifting is difficult to occur. have. Moreover, according to the manufacturing method of the adhesive sheet of this invention, the said adhesive sheet can be manufactured effectively.
[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1, 1a Adhesive layer 1b Adhesive layer of a part other than a predetermined shape 2 Light release sheet 3 Heavy release sheet 4, 4a Protective film 4b Protective film of a part other than a predetermined shape 5 Punching position 6 Base material 7 Adhesive layer 8 Sheet 11 End of Adhesive Layer 21 End of Light Release Sheet 100 Adhesive Sheet 200 Laminated Sheet (A)
300 Laminated sheet (B)
400 Laminated sheet (C)

Claims (4)

The following steps (a) ~ step (d) is possess,
Step (a): A step of laminating a heavy release sheet, a pressure-sensitive adhesive layer having a thickness of 75 to 500 μm, and a protective film having a lower peeling force than the heavy release sheet to obtain a laminated sheet (A) Step (b): A process of punching the pressure-sensitive adhesive layer and protective film of the laminated sheet (A) into a predetermined shape to obtain the laminated sheet (B) Step (c): Protection of a portion other than the predetermined shape from the laminated sheet (B) A laminated sheet (C) in which the film, the pressure-sensitive adhesive layer other than the predetermined shape, and the protective film of the predetermined shape are removed, and the pressure-sensitive adhesive layer is provided on the heavy release sheet Step (d): The laminated sheet (C) is formed such that the distance from the end of the pressure-sensitive adhesive layer to the end of the light release sheet is at least partly 8 to 35 mm. Adhere to the adhesive layer of the Obtaining a pressure-sensitive adhesive sheet adhesive layer is formed by pinched by the sheet and the heavy release sheet
The pressure-sensitive adhesive sheet has a peeling force of 30 to 90 mN / 25 mm at the interface between the light release sheet and the pressure-sensitive adhesive layer measured by the following measurement method (1), and is measured by the following measurement method (2). The peeling force at the interface between the heavy release sheet and the pressure-sensitive adhesive layer is 150 to 300 mN / 25 mm,
A method for producing a pressure-sensitive adhesive sheet, wherein the area of the light release sheet is larger than the area of the pressure-sensitive adhesive layer in contact with the light release sheet .
Measurement method (1): For an adhesive sheet sample left for 168 hours under conditions of 23 ° C. and 50% RH, the adhesive sheet sample was cut into a width of 25 mm × a length of 200 mm in accordance with JIS Z 0237, and then peeled off. The peel side at the interface between the light release sheet and the pressure-sensitive adhesive layer is measured by fixing the sheet side to a stainless steel plate and pulling the light release sheet in a 180 ° direction at a speed of 300 mm / min using a tensile tester. .
Measurement method (2): The light release sheet was peeled from the pressure-sensitive adhesive sheet sample, and the pressure-sensitive adhesive layer exposed was attached to a stainless steel plate, and the heavy release sheet was rotated 180 ° at a speed of 300 mm / min using a tensile tester. The peel strength at the interface between the heavy release sheet and the pressure-sensitive adhesive layer is measured. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the light release sheet has a thickness of 25 to 75 µm. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the peeling force of the heavy release sheet is 2.5 times or more of the peeling force of the light release sheet. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive layer surface in contact with the light release sheet and the heavy release sheet is square.

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