KR20180111471A - Protective sheet - Google Patents

Abstract

It is an object of the present invention to provide a protective sheet, which can suppress the peeling electrification voltage to a low level, has an adhesive layer with excellent heat resistance, and can secure good adhesive properties of the adhesive layer. As a means for solving the problem, as the protective sheet (1) for protecting a device, provided is the protective sheet (1), which comprises: a substrate (2) having a plastic film (21) and an antistatic layer (22a) formed on at least one surface side of the plastic film (21); and an adhesive layer (3) laminated on the substrate (2) so as to be in contact with the antistatic layer (22a), and the adhesive layer (3) is made of a silicone-based adhesive.

Description

Protective Sheet {PROTECTIVE SHEET}

The present invention relates to a protective sheet used for protecting a device.

Conventionally, in a device such as an optical member or an electronic member, in order to prevent scratches on the surface during processing such as processing, assembly, and inspection, when a protective sheet made of a plastic film and a pressure-sensitive adhesive layer is adhered to the surface of the device . This protective sheet is peeled off from the device at the time when the need for protection is eliminated, but there is a case where static electricity is generated by the peeling charge.

When static electricity is generated, dust or dirt in the air adheres to the device, leading to defective devices. Therefore, it is required that the protective sheet is provided with antistatic property so that static electricity is not generated.

As a protective sheet having antistatic properties, for example, Patent Document 1 discloses a protective sheet comprising a substrate having a first surface and a second surface, an antistatic layer provided on the first surface of the substrate, and a pressure- And a pressure-sensitive adhesive layer formed on the surface protective film.

Japanese Patent Laid-Open Publication No. 2016-135592

[0003] In recent years, as an optical member, a transition from a liquid crystal device to an organic light emitting diode (OLED) device has been actively performed. Further, studies on an OLED device having a flexible property (hereinafter referred to as a " flexible OLED device ") have been actively studied. Since the flexible OLED device is flexible, unlike a liquid crystal device or an ordinary OLED device, it is difficult to peel it from a flexible OLED device when a conventional protective sheet is used, and furthermore, Peeling is easy to fight. In the protective sheet described in Patent Document 1, it is intended to reduce the peeling electrification voltage by the kV order. However, considering the flexible OLED device, it is required to reduce the peeling electrification voltage by the V order.

Further, in an inspection process of an OLED device, there is a case where the device is exposed under a high temperature condition. The pressure-sensitive adhesive layer of the protective sheet used for such an OLED device is required to exhibit a stable adhesive force at the time of inspection under high temperature or afterward. That is, the protective sheet used in such applications requires heat resistance.

Further, in the above-mentioned protective sheet, when the protective sheet is peeled from the adherend, it is necessary that the adhesive does not remain on the adherend side. That is, the pressure-sensitive adhesive layer of the protective sheet is required to have good adhesion to the substrate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and provides a protective sheet capable of suppressing the peeling electrification voltage to a low level and having excellent heat resistance of the pressure-sensitive adhesive layer and securing good substrate adhesion of the pressure- .

In order to achieve the above object, first, the present invention provides a protective sheet for protecting a device, comprising: a plastic film; a substrate having an antistatic layer formed on at least one side of the plastic film; The present invention provides a protective sheet comprising a pressure-sensitive adhesive layer laminated on a substrate, wherein the pressure-sensitive adhesive layer is made of a silicone-based pressure-sensitive adhesive (Invention 1).

In the above invention (Invention 1), by having an antistatic layer at least between the plastic film and the pressure-sensitive adhesive layer, the peeling electrification voltage can be suppressed to be low. Therefore, it is not necessary to add an antistatic agent to the pressure-sensitive adhesive layer, and good adhesion of the pressure-sensitive adhesive layer to the substrate can be ensured. Further, since the adhesive force of the silicone adhesive is stable even at a high temperature, the adhesive layer made of the silicone adhesive is excellent in heat resistance.

In the above invention (Invention 1), the surface roughness of the surface of the plastic film on the side of the pressure-sensitive adhesive layer is 200 nm or less as the maximum peak height Rp, 300 nm or less as the maximum height (Rz) The maximum cross-sectional height (Rt) is preferably 500 nm or less (Invention 2).

In the invention (inventions 1 and 2), it is preferable that an antistatic layer is formed on the other side of the plastic film (invention 3).

In the above invention (inventions 1 to 3), a release sheet is laminated on a surface of the pressure-sensitive adhesive layer opposite to the base, and the release sheet is provided on a surface of the pressure- It is preferable to have an antistatic layer (invention 4).

In the above inventions (inventions 1 to 4), it is preferable that the haze value of the protective sheet from which the release sheet is removed is 5% or less (invention 5).

In the above inventions (inventions 1 to 5), when a voltage of 100 V is applied to the substrate for 10 seconds under an environment of 23 ° C. and a relative humidity of 50%, the surface of the surface of the substrate on the pressure- It is preferable that the resistivity is not less than 1 x 10 ⁵ ? / Sq and not more than 1 x 10 ⁹ ? / Sq (invention 6).

In the above inventions (inventions 1 to 6), when a voltage of 100 V is applied to the substrate for 10 seconds under an environment of 23 ° C. and a relative humidity of 50%, the pressure difference between the pressure- It is preferable that the surface resistivity of the surface is 1 x 10 ⁷ Ω / sq or more and 5 × 10 ¹¹ Ω / sq or less (invention 7).

In the above invention (Invention 4), when a voltage of 100 V is applied to the peeling sheet for 10 seconds under an environment of 23 ° C. and a relative humidity of 50%, the surface of the peeling sheet side of the peeling sheet It is preferable that the resistivity is not less than 1 x 10 ⁷ ? / Sq and not more than 1 x 10 ¹¹ ? / Sq (invention 8).

In the above invention (Invention 4), a voltage of 100 V is applied to the peeling sheet for 10 seconds under an environment of 23 ° C. and a relative humidity of 50%, and the peeling sheet is peeled off from the peeling sheet It is preferable that the surface resistivity of the surface is 1 x 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less (Invention 9).

In the above inventions (Invention 1 to 9), it is preferable that the device is a flexible device (invention 10).

The protective sheet according to the present invention can suppress the peeling electrification voltage to a low level, and is excellent in the heat resistance of the pressure-sensitive adhesive layer and can ensure good adhesion of the pressure-sensitive adhesive layer to the substrate.

1 is a sectional view of a protective sheet according to an embodiment of the present invention;
2 is a drawing (color) showing an image of an evaluation reference in a test example concerning evaluation of an adhesive surface;

Hereinafter, an embodiment of the present invention will be described.

A protective sheet according to an embodiment of the present invention is used to protect a device, in order to prevent scratches on the surface of the device during processing such as processing, assembly, and inspection of the device.

The protective sheet according to the present embodiment includes a substrate and a pressure-sensitive adhesive layer. The substrate has a plastic film and an antistatic layer formed on at least one side of the plastic film, and the pressure-sensitive adhesive layer is laminated on the substrate so as to contact the antistatic layer. The pressure-sensitive adhesive layer is made of a silicone-based pressure-sensitive adhesive.

In the protective sheet according to the present embodiment, at least the antistatic layer is provided between the plastic film and the pressure-sensitive adhesive layer, whereby the peeling electrification voltage can be suppressed to a low level. Therefore, when the release sheet is peeled from the pressure-sensitive adhesive layer and the protective sheet is adhered to the device, or when the protective sheet is peeled from the device, dust and dirt in the air can be prevented from adhering to the device due to static electricity. In addition, even when the device as a substrate is a flexible OLED device, the above-described effect can be obtained and it is possible to prevent the flexible OLED device from being damaged by static electricity.

In addition, the silicone-based pressure-sensitive adhesive is easily tacky (slightly tacky) and is excellent in re-peeling property. Therefore, the protective sheet according to the present embodiment can be smoothly peeled off from a flexible flexible device such as a flexible OLED device.

Further, the silicone pressure-sensitive adhesive has a stable adhesive force even at a high temperature and is excellent in heat resistance as compared with the acrylic pressure-sensitive adhesive. Therefore, even when a device such as an OLED device to which the protective sheet is adhered is inspected at a high temperature (for example, 90 to 150 占 폚), the protective sheet according to the present embodiment in which the pressure-sensitive adhesive layer is made of a silicone- So that the protective sheet can be peeled from the adherend without any problem.

In addition, the protective sheet according to the present embodiment is excellent in antistatic property by having an antistatic layer between the plastic film and the pressure-sensitive adhesive layer as described above, so that it is not necessary to add an antistatic agent to the pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer formed by adding a common antistatic agent to a silicone-based pressure-sensitive adhesive lowers the adhesion of the base material. However, such a problem can be avoided in the protective sheet according to the present embodiment, and satisfactory adhesion of the pressure-sensitive adhesive layer to the substrate can be ensured. Therefore, the protective sheet according to the present embodiment has high stability and reliability as a product, and can suppress the remaining of the adhesive on the adherend when peeling off the protective sheet from the adherend.

Hereinafter, a protective sheet as an example of the present embodiment will be described with reference to the drawings.

1, the protective sheet 1 according to the present embodiment includes a base material 2, a pressure-sensitive adhesive layer 3, and a release sheet 4. As shown in Fig. The substrate 2 has a plastic film 21 and a first antistatic layer 22a formed on the surface of the plastic film 21 on the side of the pressure-sensitive adhesive layer 3 (lower surface in Fig. 1) It is preferable that the plastic film 21 further has a second antistatic layer 22b formed on the surface opposite to the pressure-sensitive adhesive layer 3 (upper surface in Fig. 1). The release sheet 4 has a support 41 and a third antistatic layer 42a formed on the surface of the support 41 on the side of the pressure sensitive adhesive layer 3 It is particularly preferable to further include a fourth antistatic layer 42b formed on the surface of the support 41 opposite to the pressure-sensitive adhesive layer 3 (the lower surface in Fig. 1). The pressure sensitive adhesive layer 3 is laminated on the base material 2 so as to be in contact with the first antistatic layer 22a of the base material 2. [ The release sheet 4 in the present embodiment is laminated on the pressure sensitive adhesive layer 3 such that the third antistatic layer 42a of the release sheet 4 is in contact with the pressure sensitive adhesive layer 3. [

The release sheet 4 is for protecting the pressure-sensitive adhesive layer 3 until the protective sheet 1 is used and is peeled off when the protective sheet 1 is used. In the protective sheet 1 according to the present embodiment, the release sheet 4 may be omitted.

In this embodiment, the first antistatic layer 22a of the substrate 2 is an essential element, but the second antistatic layer 22b of the substrate 2 and the third antistatic layer 22b of the release sheet 4 42a and the fourth antistatic layer 42b are not necessarily required and may be omitted independently of each other. However, since one or more layers of the second antistatic layer 22b of the base material 2, the third antistatic layer 42a of the release sheet 4, and the fourth antistatic layer 42b are present, The antistatic property of the photoconductor 1 becomes better.

As a preferred use of the protective sheet 1, the protective sheet 1 is fed out from the roll of the protective sheet 1, the release sheet 4 is peeled off, And a flexible OLED device is installed on a pressure-sensitive adhesive layer 3, and is transported, processed, and the like. It is preferable that at least one of the second antistatic layer 22b and the fourth antistatic layer 42b be provided in order to prevent the electrification in the above-described elongating process, and it is more preferable that both the antistatic layer 22b and the fourth antistatic layer 42b are provided. It is preferable that a third antistatic layer 42a in contact with the pressure-sensitive adhesive layer 3 is provided in addition to the first antistatic layer 22a in order to prevent electrification in the peeling sheet 4 described above Do.

1. Each member

(1)

(1-1) Plastic film

Although the plastic film 21 is not particularly limited, when the adherend is an OLED device, the plastic film 21 preferably has high transparency. This is because, in the light emission inspection of the OLED device, the inspection is performed at a stricter level than the light emission inspection of the liquid crystal device, and the protective sheet 1 is required to have high transparency. In this case, it is preferable that the plastic film 21 does not contain a filler. Further, when the adherend is an OLED device, it is preferable that the plastic film 21 has heat resistance to a high temperature (for example, 90 to 150 DEG C) applied in the inspection of the OLED device.

As the plastic film 21, for example, a resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyimide, polyether imide, polycarbonate, polymethylpentene, polyphenylene sulfide, , And may be a single layer film or a laminate of a plurality of layers of the same or different types. Of these, polyethylene terephthalate films are particularly preferable in view of transparency, heat resistance and cost.

The plastic film may contain additives such as a filler, a heat resistance improving agent, and an ultraviolet absorber within the range not impairing the above-described effects of the present embodiment.

The plastic film 21 may be subjected to surface treatment or primer treatment by an oxidizing method or the like as desired for the purpose of improving adhesion with the first antistatic layer 22a and / or the second antistatic layer 22b can do. Examples of the oxidation method include a corona discharge treatment, a plasma discharge treatment, a chromium oxidation treatment (wet), a flame treatment, a hot air treatment, an ozone, and an ultraviolet ray irradiation treatment. These surface treatment methods are appropriately selected depending on the kind of the plastic film 21. [

The thickness of the plastic film 21 is preferably 25 占 퐉 or more, more preferably 38 占 퐉 or more, and more preferably 50 占 퐉 or more, in consideration of heat resistance and workability of adhering and peeling. In the case where the device to be protected is a flexible device, it is particularly preferable that the protective device is 50 mu m or more from the viewpoint of operability of attaching and peeling. On the other hand, in consideration of workability and cost of attaching and peeling, the thickness is preferably 150 占 퐉 or less, more preferably 125 占 퐉 or less, and further preferably 100 占 퐉 or less.

The surface roughness of the surface of the plastic film 21 on the side of the pressure-sensitive adhesive layer 3 (first antistatic layer 22a side) is preferably 10 nm or less as an arithmetic mean roughness (Ra) Particularly preferably 5 nm or less, and more preferably 3 nm or less. As a result, the haze value of the plastic film 21, in particular, the external haze is reduced, and the transparency is higher. The surface roughness in the present specification is determined from a roughness curve measured using an optical interference microscope in accordance with JIS B0601: 2001. Specifically, it is as shown in a test example. The surface roughness of the plastic film in this specification includes not only the surface roughness of the plastic film alone but also the surface roughness of the plastic film having the adhesive layer or the like.

The lower limit value of the arithmetic mean roughness (Ra) is not particularly limited, but is preferably 1 nm or more, particularly preferably 1.5 nm or more, and more preferably 2 nm or more.

The surface roughness of the surface of the plastic film 21 on the pressure sensitive adhesive layer 3 side (first antistatic layer 22a side) is 200 nm or less as the maximum peak height Rp, And a maximum cross-sectional height (Rt) of 500 nm or less. By satisfying the above-described requirement, the plastic film 21 is prevented from becoming the sticky surface of the pressure-sensitive adhesive layer 3 (surface on which the pressure-sensitive adhesive layer comes into contact with the adherend) as the surface of the sticky material, The transparency of the sheet 1 becomes very high. Therefore, for example, the luminescence inspection of the OLED device to which the protective sheet 1 having the plastic film 21 is adhered can be performed more accurately.

The maximum peak height Rp is preferably 200 nm or less, particularly preferably 150 nm or less, and more preferably 100 nm or less, from the viewpoint of suppressing the surface of the citron peel. The maximum height (Rz) is preferably 300 nm or less, particularly preferably 200 nm or less, more preferably 100 nm or less, from the viewpoint of suppressing the surface of the citron peel. The maximum cross-sectional height (Rt) is preferably 500 nm or less, more preferably 400 nm or less, particularly preferably 300 nm or less, further preferably 200 nm or less, from the viewpoint of suppressing the surface of the citron peel. The lower limit value of the maximum peak height Rp is not particularly limited, but is preferably 5 nm or more, particularly preferably 10 nm or more, and more preferably 20 nm or more. The lower limit value of the maximum height (Rz) is not particularly limited, but is preferably 5 nm or more, particularly preferably 10 nm or more, and more preferably 20 nm or more. The lower limit value of the maximum sectional height (Rt) is not particularly limited, but is preferably 5 nm or more, particularly preferably 20 nm or more, and more preferably 40 nm or more.

(1-2) Antistatic Layer

All of the first antistatic layer 22a and the second antistatic layer 22b are not particularly limited as long as they are made of a material that can impart desired antistatic properties to the plastic film 21 and have transparency. As such antistatic layers 22a and 22b, for example, a layer made of a composition for an antistatic layer containing a conductive polymer and a binder resin is preferable.

As the conductive polymer, arbitrary ones may be selected and used as appropriate from conventionally known conductive polymers. Among them, polythiophene-based, polyaniline-based or polypyrrole-based conductive polymers are preferable. The conductive polymer may be used singly or in combination of two or more kinds.

Examples of the polythiophene conductive polymer include polythiophene, poly (3-alkylthiophene), poly (3-thiophene-beta-ethanesulfonic acid), polyalkylene dioxythiophene and polystyrene sulfonate (PSS) (including those doped), and the like. Among these, a mixture of polyalkylene dioxythiophene and polystyrene sulfonate is preferable. Examples of the polyalkylene dioxythiophenes include poly (3,4-ethylenedioxythiophene) (PEDOT), polypropylene dioxythiophene and poly (ethylene / propylene) dioxythiophene. , 4-ethylenedioxythiophene) are preferable. That is, a mixture of poly (3,4-ethylenedioxythiophene) and polystyrene sulfonate (PEDOT doped with PSS) is particularly preferable among the above.

Examples of the polyaniline-based conductive polymer include polyaniline, polymethylaniline, polymethoxyaniline, and the like. Examples of the polypyrrole-based conductive polymer include polypyrrole, poly-3-methylpyrrole, poly-3-octylpyrrole, and the like.

The content of the conductive polymer in the antistatic layer composition is preferably from 0.1 to 30 mass%, more preferably from 0.2 to 20 mass%, still more preferably from 0.3 to 10 mass%. When the content of the conductive polymer is within the above range, good antistatic performance can be obtained and the antistatic layer formed of the antistatic layer composition can have sufficient strength.

The binder resin used for the antistatic layer composition preferably contains at least one member selected from the group consisting of a polyester resin, a urethane resin and an acrylic resin as a main component. These resins may be thermosetting compounds or ultraviolet-curable compounds, but in order to obtain ultraviolet-curable properties, it is necessary to replace the solvent with an organic solvent system from a water-based system, and therefore a thermosetting compound is preferable from the viewpoint of the number of steps and cost. Of the above-mentioned materials, a thermosetting polyester resin is preferable from the viewpoint of high adhesion to a plastic film, and a polyester resin having a reactive group reactive with a crosslinking agent such as a hydroxyl group is particularly preferable.

The antistatic layer composition may contain, in addition to the above components, a crosslinking agent, a leveling agent, and an antifouling agent.

The cross-linking agent may be any one capable of crosslinking the above-mentioned resin. For example, if the resin has a hydroxyl group as a reactive group, it is preferable to use an isocyanate type crosslinking agent, an epoxy type crosslinking agent, an amine type crosslinking agent, a melamine type crosslinking agent and the like.

The content of the crosslinking agent is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and most preferably 10 to 30 parts by mass, relative to 100 parts by mass of the binder resin.

As the leveling agent, for example, a dimethylsiloxane-based compound, a fluorine-based compound, a surfactant and the like can be used. In the first antistatic layer 22a, it is preferable to use a surfactant from the viewpoint of adhesion with the pressure-sensitive adhesive layer (3). By including the leveling agent in the composition for the antistatic layer, the smoothness of the antistatic layers 22a and 22b can be improved, and the transparency of the base material 2 becomes higher.

The content of the leveling agent in the antistatic layer composition is preferably from 0.1 to 10 mass%, particularly preferably from 0.2 to 5 mass%, more preferably from 0.5 to 3 mass%.

The thicknesses of the first antistatic layer 22a and the second antistatic layer 22b are preferably 10 nm or more, more preferably 20 nm or more, and more preferably 30 nm or more, in consideration of antistatic performance . The thickness of the first antistatic layer 22a and the second antistatic layer 22b is preferably 200 nm or less, particularly preferably 150 nm or less, and more preferably 100 nm or less, from the viewpoints of strength and cost .

(1-3) Physical properties of substrate

(1-3-1) Surface resistivity

The surface of the base material 2 on the pressure-sensitive adhesive layer 3 side (the surface of the first antistatic layer (the surface of the first antistatic layer The surface resistivity on the side opposite to the plastic film 21 on the surface of the plastic film 22a is preferably not more than 1 x 10 ⁹ ? / Sq as the upper limit value, more preferably not more than 5 x 10 ⁸ ? / Sq, × 10 ⁸ Ω / sq or less. By virtue of the above-described upper limit of the surface resistivity, the peeling electrification voltage can be effectively suppressed. Therefore, it is possible to effectively suppress generation of static electricity when the release sheet 4 is peeled from the pressure-sensitive adhesive layer 3 or when the protective sheet 1 is peeled from the device. The lower limit value of the surface resistivity is not particularly limited, but is preferably 1 10 ⁵ Ω / sq or higher, particularly preferably ⁵ 10 ⁵ Ω / sq or higher, and more preferably 1 10 ⁶ Ω / sq or higher More preferable.

The surface of the substrate 2 opposite to the pressure-sensitive adhesive layer 3 (the surface opposite to the pressure-sensitive adhesive layer 3) when applied with a voltage of 100 V to the substrate 2 for 10 seconds under an environment of 23 캜 and a relative humidity of 50% The surface resistivity of the antistatic layer 22b on the side opposite to the plastic film 21 is preferably 5 x 10 ¹¹ ? / Sq or less as an upper limit value and 1 x 10 ¹¹ ? / Sq or less And more preferably 5 10 ¹⁰ ? / Sq or less. The above-mentioned upper limit of the surface resistivity can prevent the generation of static electricity more effectively when the protective sheet 1 is fed out from the winding roll of the protective sheet 1. The lower limit of the surface resistivity is not particularly limited, but is preferably 1 x 10 ⁷ ? / Sq or more, particularly preferably 5 x 10 ⁷ ? / Sq or more, and more preferably 1 x 10 ⁸ ? / Sq or more More preferable.

The surface resistivity is a value measured in accordance with JIS K6911, and details of the method for measuring the surface resistivity are as shown in the following test examples.

(1-3-2) Haze value

The haze value of the base material 2 is preferably 5% or less, particularly preferably 3% or less, more preferably 1% or less. The transparency of the protective sheet 1 to be adhered to the adherend is high due to the above haze value of the base material 2. Since the plastic film 21 is made of a plastic film that does not contain a filler, the aforementioned haze value is easily attained. Further, when the arithmetic mean roughness (Ra) of the plastic film 21 is in the above-mentioned range, the aforementioned haze value is more easily attained. The lower limit value of the haze value is not particularly limited, and is particularly preferably 0%. Here, the haze value in this specification is a value measured in accordance with JIS K7136: 2000.

(2) Pressure-sensitive adhesive layer

(2-1) Material

The pressure-sensitive adhesive layer (3) is made of a silicone-based pressure-sensitive adhesive. As the silicone-based pressure-sensitive adhesive, it is preferable to select a silicone pressure-sensitive adhesive suitable for adhesion to an adherend (device) to be protected and release from the adherend. For example, when the adherend is a flexible device such as an OLED device, it is preferable to select a tacky silicone pressure-sensitive adhesive which is particularly excellent in releasability so that the protective sheet 1 can easily peel off from the flexible device.

The silicone-based pressure-sensitive adhesive may be a condensation-type silicone pressure-sensitive adhesive or an addition reaction-type silicone pressure-sensitive adhesive, but an addition reaction-type silicone pressure-sensitive adhesive is preferable from the viewpoint of re-

The addition reaction-type silicone-based pressure-sensitive adhesive contains as its main components an addition reaction-type silicone resin obtained from a first polydimethylsiloxane having at least two alkenyl groups in one molecule and a second polydimethylsiloxane having at least two hydrosilyl groups in one molecule , And it is particularly preferable to further contain silicone resin.

Examples of the alkenyl group contained in the first polydimethylsiloxane include monovalent hydrocarbon groups such as a vinyl group, an allyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group and an octenyl group. Particularly preferred.

The content of the alkenyl group in the first polydimethylsiloxane (the ratio of the number of alkenyl groups to the number of methyl groups bonded to silicon atoms) is preferably 0.005 to 0.1 mol%, more preferably 0.01 to 0.05 mol% desirable. The alkenyl group preferably has both ends of the molecular chain and may have a side chain. When at least two alkenyl groups are contained in one molecule of the first polydimethylsiloxane and the content of the alkenyl group is in the above range, a crosslinked structure having a high crosslinking density is formed to obtain a pressure-sensitive adhesive layer (3) excellent in re- .

The degree of polymerization (number of siloxane bonds) of the first polydimethylsiloxane is preferably 200 to 5,000, particularly preferably 500 to 3,000. The content of the hydrosilyl group in the second polydimethylsiloxane is preferably 2 to 300 in one molecule, particularly preferably 4 to 200. The polymerization degree of the second polydimethylsiloxane is preferably from 50 to 2,000, particularly preferably from 100 to 1,500. The blending ratio of the second polydimethylsiloxane to 100 parts by mass of the first polydimethylsiloxane is preferably 0.01 to 20 parts by mass, particularly preferably 0.1 to 10 parts by mass. The addition reaction of the first polydimethylsiloxane with the second polydimethylsiloxane is favorably performed because the content of each functional group and the blending ratio of the second polydimethylsiloxane to the first polydimethylsiloxane fall within the above range.

The first polydimethylsiloxane preferably has no hydrosilyl group, and the second polydimethylsiloxane preferably has no alkenyl group.

The weight average molecular weight of the first polydimethylsiloxane is preferably from 20,000 to 130,000, and particularly preferably from 300,000 to 1,000,000. The weight average molecular weight of the second polydimethylsiloxane is preferably 300 to 1,400, and particularly preferably 500 to 1,200. In the present specification, the weight average molecular weight is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

As the silicone resin can be used, for example, a MQ resin consisting of one functional siloxane unit _{[(CH₃) 3 SiO 1/} 2] of M units, and a four-functional siloxane units Q units of [SiO _4/2]. The molar ratio of M units / Q units is preferably 0.6 to 1.7. This silicone resin has a role of imparting tackiness to the silicone-based tackifier.

The amount of the silicone resin to be blended with 100 parts by mass of the addition reaction type silicone resin is preferably 1 part by mass or more, particularly preferably 3 parts by mass or more, more preferably 5 parts by mass or more. The lower limit of the amount of the silicone resin to be added is that the desired adhesion can be obtained and the protective sheet 1 can be prevented from unintentionally peeling off from the adherend (device). The upper limit of the blending amount is preferably 40 parts by mass or less, particularly preferably 30 parts by mass or less, more preferably 20 parts by mass or less. The upper limit value of the amount of the silicone resin to be added is prevented from being too high by the above-mentioned adhesive force, and the re-peeling property of the protective sheet 1 can be ensured.

The addition reaction type silicone based pressure sensitive adhesive preferably contains a catalyst. The catalyst is not particularly limited as long as it can cure the addition reaction type silicone resin (addition reaction of the first polydimethylsiloxane and the second polydimethylsiloxane), but among these, a platinum group metal compound is preferable. Examples of the platinum group metal compound include fine platinum particles, fine particulate platinum adsorbed on a carbon powder carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium and rhodium . By containing such a catalyst, the curing reaction of the addition reaction type silicone resin can be promoted more efficiently.

The blending amount of the catalyst relative to 100 parts by mass of the addition reaction type silicone resin is preferably 0.01 to 3 parts by mass, particularly preferably 0.05 to 2 parts by mass.

The silicone-based pressure-sensitive adhesive may contain various additives such as a crosslinking agent, a reaction inhibitor, and a silane coupling agent. On the other hand, the silicone-based pressure-sensitive adhesive preferably does not contain an antistatic agent. When a general antistatic agent is added to a silicone pressure sensitive adhesive, the adhesion of the obtained pressure sensitive adhesive layer (3) is lowered, and the transparency of the pressure sensitive adhesive layer (3) is lowered due to low compatibility. However, if the antistatic agent does not cause such defects, it may be added to the silicone-based pressure-sensitive adhesive.

(2-2) Thickness

The thickness of the pressure-sensitive adhesive layer 3 is preferably 15 占 퐉 or more, particularly preferably 20 占 퐉 or more, and more preferably 25 占 퐉 or more, from the viewpoint of adhesiveness. The thickness of the pressure-sensitive adhesive layer 3 is preferably 75 占 퐉 or less, more preferably 50 占 퐉 or less, and most preferably 30 占 퐉 or less, from the viewpoint of releasability.

(3) Peeling sheet

(3-1)

The support 41 is not particularly limited as long as it does not adversely affect the pressure-sensitive adhesive layer 3. Examples of the support 41 include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, Vinyl acetate copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene (meth) acrylic acid copolymer film, Ethylene / (meth) acrylic acid ester copolymer films, polystyrene films, polycarbonate films, polyimide films, fluororesin films, and the like. These crosslinked films are also used. Further, these laminated films may be used. Of these, polyethylene terephthalate films having excellent handling properties are preferable.

The thickness of the support body 41 is not particularly limited, but is preferably 15 to 100 占 퐉, and particularly preferably 25 to 75 占 퐉.

(3-2) Antistatic layer

The third antistatic layer 42a and the fourth antistatic layer 42b are not particularly limited as long as they are made of a material capable of imparting desired antistatic properties to the plastic film 21. [ As the material of the antistatic layers 42a and 42b, it is preferable to use the same materials as the antistatic layers 22a and 22b of the substrate 2 described above. The thickness of the antistatic layers 42a and 42b is preferably the same as that of the antistatic layers 22a and 22b of the substrate 2. [

Here, as described above, either or both of the third antistatic layer 42a and the fourth antistatic layer 42b may be omitted in the protective sheet 1 according to the present embodiment. However, in the case of omitting one side, it is preferable to omit the fourth antistatic layer 42b. If the third antistatic layer 42a is in contact with the pressure-sensitive adhesive layer 3, the antistatic property when the release sheet 4 is peeled from the pressure-sensitive adhesive layer 3 can be effectively increased.

(3-3) Properties of release sheet

(3-3-1) Surface resistivity

The surface of the release sheet 4 on the side of the pressure-sensitive adhesive layer 3 (the surface of the release sheet 4 when the voltage of 100 V was applied to the release sheet 4 for 10 seconds under an environment of 23 캜 and a relative humidity of 50% The surface resistivity of the surface of the resist layer 42a opposite to the support 41 is preferably not more than 1 x 10 ¹¹ ? / Sq as an upper limit value, more preferably not more than 5 x 10 ¹⁰ ? / S, More preferably 10 ¹⁰ ? / S or less. The above-mentioned upper limit of the surface resistivity allows the static electricity to be well suppressed from occurring when the release sheet 4 is peeled from the pressure-sensitive adhesive layer 3, and when the protective sheet 1 is adhered to the device , It is possible to more effectively suppress the attachment of dust or dirt in the air to the device. Although the lower limit value of the surface resistivity is not particularly limited, it is preferably 1 x 10 ⁷ ? / Sq or more, particularly preferably 5 x 10 ⁷ ? / S or more, and more preferably 1 x 10 ⁸ ? More preferable.

(The side opposite to the pressure-sensitive adhesive layer 3 in the release sheet 4 when a voltage of 100 V was applied to the release sheet 4 for 10 seconds under an environment of 23 deg. C and a relative humidity of 50% The surface resistivity of the antistatic layer 42b on the side opposite to the support 41 is preferably not more than 1 x 10 ¹¹ ? / Sq as an upper limit value, particularly preferably not more than 5 x 10 ¹⁰ ? / S , And more preferably 1 × 10 ¹⁰ Ω / s or less. The above-mentioned upper limit of the surface resistivity can prevent the generation of static electricity more effectively when the protective sheet 1 is fed out from the winding roll of the protective sheet 1. Although the lower limit value of the surface resistivity is not particularly limited, it is preferably 1 x 10 ⁷ ? / Sq or more, particularly preferably 5 x 10 ⁷ ? / S or more, and more preferably 1 x 10 ⁸ ? More preferable.

(3-3-2) Surface roughness

The surface roughness of the side of the pressure-sensitive adhesive layer 3 side (on the side of the third antistatic layer 42a) of the release sheet 4 is 100 nm or less as an arithmetic mean roughness (Ra) Preferably 1500 nm or less as the maximum height Rz and 1500 nm or less as the maximum height Rz, and 2000 nm or less as the maximum cross-sectional height Rt. By satisfying the above requirement, the peeling sheet 4 is more effectively suppressed from becoming the sticking surface of the pressure-sensitive adhesive layer 3 in contact with the peeling sheet 4, The visibility of the sheet 1 becomes higher. Therefore, for example, the luminescence inspection of the OLED device to which the protective sheet 1 having the plastic film 21 is adhered can be performed more accurately.

From the viewpoint of inhibiting the surface of the pressure-sensitive adhesive layer 3, the arithmetic mean roughness (Ra) is preferably 100 nm or less, particularly preferably 75 nm or less, and more preferably 50 nm or less. The maximum peak height Rp is preferably 1500 nm or less, particularly preferably 1250 nm or less, and more preferably 1000 nm or less. The maximum height Rz is preferably 1500 nm or less, particularly preferably 1250 nm or less, and more preferably 1000 nm or less. The maximum cross-sectional height (Rt) is preferably 2000 nm or less, particularly preferably 1750 nm or less, and more preferably 1500 nm or less. The lower limit value of the arithmetic mean roughness (Ra) is not particularly limited, but is preferably 5 nm or more, particularly preferably 10 nm or more, and more preferably 20 nm or more. The lower limit value of the maximum peak height Rp is not particularly limited, but is preferably 50 nm or more, particularly preferably 100 nm or more, more preferably 200 nm or more. The lower limit value of the maximum height (Rz) is not particularly limited, but is preferably 50 nm or more, particularly preferably 100 nm or more, more preferably 200 nm or more. The lower limit value of the maximum sectional height (Rt) is not particularly limited, but is preferably 200 nm or more, particularly preferably 300 nm or more, more preferably 400 nm or more.

(3-4) Others

It is preferable that the surface of the release sheet 4 in contact with the pressure-sensitive adhesive layer 3 in the present embodiment is not subjected to the release treatment, that is, the release agent layer is not present. When a release agent layer made of a fluorine-based release agent is provided, the fluorine component migrates to the pressure-sensitive adhesive layer 3 and a pressure-sensitive adhesive layer 3 is formed on the pressure-sensitive adhesive layer 3, The antistatic property and the adhesive force of the resin composition may not be stable.

2. Manufacturing method of protective sheet

(1) Preparation of substrate

In order to manufacture the base material 2 in this embodiment, as an example, a coating liquid containing a composition for an antistatic layer and, if desired, a solvent is applied to one surface of a plastic film 21, , And the first antistatic layer 22a is formed by curing. A second antistatic layer 22b is formed by applying a coating solution containing a composition for an antistatic layer and, if desired, a solvent, on the other surface of the plastic film 21, do.

The solvent is not particularly limited, and various solvents can be used. For example, an ether solvent, an alcohol solvent, a mixed solvent of an alcohol solvent and purified water, and the like are used.

The application of the coating liquid of the antistatic layer composition may be carried out by a conventional method, and examples thereof include a gravure coating method, a bar coating method, a spray coating method, a spin coating method, a knife coating method, a roll coating method, Or the like.

When the coating liquid is applied, it is preferable to heat and dry the coating film. The heating temperature for heating and drying is preferably 70 to 140 캜, and the heating time is preferably about 30 to 60 seconds.

(2) Production of release sheet

The release sheet 4 in the present embodiment can be produced by the same method as the production method of the base material 2. [ That is, in order to manufacture the release sheet 4, as an example, a coating liquid containing a composition for an antistatic layer and, if desired, a solvent is applied to one surface of a support 41, followed by drying and curing Thereby forming the third antistatic layer 42a. Further, a coating liquid containing a composition for an antistatic layer and, if desired, a solvent is applied to the other surface of the support 41, followed by drying and curing to form a fourth antistatic layer 42b .

(3) Production of protective sheet

In order to manufacture the protective sheet 1 according to the present embodiment, a coating liquid containing a silicone-based pressure-sensitive adhesive and, if desired, a diluent, is applied to the surface of the substrate 2 on the side of the first antistatic layer 22a After coating, drying, and curing, a pressure-sensitive adhesive layer (3) is formed.

The diluent is not particularly limited, and various diluents can be used. For example, hydrocarbon compounds such as toluene, hexane and heptane, acetone, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and mixtures thereof.

The application of the coating liquid of the silicone-based pressure-sensitive adhesive may be carried out by a conventional method, for example, by a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method or a gravure coating method. When the coating liquid is applied, it is preferable to heat and dry the coating film.

When the subject of the silicone based pressure sensitive adhesive is an addition reaction type silicone based pressure sensitive adhesive, it is preferable that the coating film is thermally cured. In this case, the heating temperature is preferably 80 to 180 DEG C, and the heating time is preferably 10 to 90 seconds or so.

When the pressure sensitive adhesive layer 3 is formed as described above, the release sheet 4 is bonded to the pressure sensitive adhesive layer 3 so that the third antistatic layer 42a is in contact with the pressure sensitive adhesive layer 3 to obtain the protective sheet 1.

Although the pressure sensitive adhesive layer 3 is formed on the base material 2 in the above-described manufacturing method, it may be formed on the release sheet 4, and then the base material 2 may be applied to the pressure sensitive adhesive layer 3 .

3. Properties

(1) Haze value

The haze value of the laminate other than the release sheet 4 (the laminate of the base material 2 and the pressure-sensitive adhesive layer 3 in the present embodiment) in the protective sheet 1 according to the present embodiment is 5% or less , More preferably not more than 3%, particularly preferably not more than 2%, further preferably not more than 1%. With the above haze value, the visibility of the protective sheet 1 becomes higher, and for example, the light emission test of the OLED device to which the protective sheet 1 is adhered can be performed without any problem. The lower limit value of the haze value is not particularly limited, and is particularly preferably 0%.

In the protective sheet 1 according to the present embodiment, since the plastic film 21 is made of a plastic film not containing a filler, the aforementioned haze value is easily attained. Further, when the arithmetic mean roughness (Ra) of the plastic film 21 is in the above-mentioned range, the aforementioned haze value is more easily attained.

(2) Pressure-sensitive adhesive layer voltage

(Base material 2 and pressure-sensitive adhesive layer 3 in the present embodiment) other than the release sheet 4 in the protective sheet 1 according to the present embodiment under an environment of 23 deg. C and a relative humidity of 50% The pressure sensitive adhesive layer 3 was placed on the turntable while the pressure sensitive adhesive layer 3 was exposed and a voltage of +10 kV was applied from a position at a distance of 2.0 cm from the pressure sensitive adhesive layer 3 while rotating the turntable. The voltage (pressure-sensitive adhesive layer voltage) is preferably 2 kV or less, particularly preferably 1.5 kV or less, more preferably 1 kV or less. By the above-described pressure-sensitive adhesive layer voltage, static electricity is unlikely to be generated when the protective sheet 1 is peeled off from the pressure-sensitive adhesive layer 3 and the protective sheet 1 is peeled from the device, This makes it possible to effectively prevent dust and dirt from adhering to the device from the air. The lower limit value of the pressure-sensitive adhesive layer voltage is not particularly limited, but is preferably 0 V. Details of the method for measuring the pressure-sensitive adhesive layer voltage are as shown in the test examples described later.

(3) Peeling Voltage

The release sheet 4 was peeled off manually from the pressure-sensitive adhesive layer 3 in the protective sheet 1 according to the present embodiment at a peeling rate of 2.0 m / min under an environment of 23 ° C. and a relative humidity of 50% (Peeling electrification voltage) at a position 2.0 cm from the exposed surface of the pressure-sensitive adhesive layer measured after 5 seconds of peeling is preferably 200 V or less, particularly preferably 150 V or less, more preferably 100 V or less. With the above-described peeling electrification voltage, static electricity is less likely to be generated when the release sheet 4 is peeled off from the pressure-sensitive adhesive layer 3, so that adhesion of dust and dirt in the air to the device due to static electricity can be effectively suppressed . The lower limit value of the peeling electrification voltage is not particularly limited, but is preferably 0V. The details of the method of measuring the peeling electrification voltage are as shown in the following test examples.

4. Usage

The protective sheet 1 according to the present embodiment is used for protecting devices in order to prevent scratches on the surface of the device during processing such as processing, assembly, and inspection of the device. However, the present invention is not limited to these applications.

The device to be protected by the protective sheet 1 may be, for example, an optical member or an electronic member. In the present embodiment, it is preferable that the device is a flexible device, It is preferable that the device is a device requiring a light emission test or a high temperature condition. Among them, OLED devices are preferred, and flexible OLED devices are particularly preferred.

Since the protective sheet 1 according to the present embodiment has the first antistatic layer 22a and the second to fourth antistatic layers 22b and 42a and 42b as well, (In particular, V order), and has excellent antistatic properties. This makes it difficult for static electricity to be generated when the release sheet 4 is peeled from the pressure-sensitive adhesive layer 3 to adhere the protective sheet 1 to the device or peeled from the device, and dust or dirt in the air It is possible to suppress the attachment to the device. The protective sheet 1 according to the present embodiment has the second antistatic layer 22b and the fourth antistatic layer 42b so that the protective sheet 1 is wound from the winding roll of the protective sheet 1 It is possible to suppress the generation of static electricity even when discharged. On the other hand, the pressure-sensitive adhesive layer (3) formed of a silicone-based pressure-sensitive adhesive is excellent in re-peeling property and can be easily peeled from a flexible device such as an OLED device. In addition, since the pressure-sensitive adhesive layer 3 formed of a silicone-based pressure-sensitive adhesive has excellent heat resistance, even when an OLED device or the like to which the protective sheet 1 is adhered is inspected at a high temperature, ) Can be peeled off from the OLED device or the like without any problem. Further, in the protective sheet 1 according to the present embodiment, it is not necessary to add an antistatic agent to the pressure-sensitive adhesive layer 3 formed of a silicone-based pressure-sensitive adhesive in order to obtain antistatic properties. The adhesion to the substrate 2 (substrate adhesion) is excellent. Thereby, the stability and reliability of the product are high, and there is no possibility that the pressure-sensitive adhesive layer (3) or the pressure-sensitive adhesive remains on the adherend when the protective sheet (1) is peeled from the adherend.

The embodiments described above are described for the purpose of facilitating understanding of the present invention and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design modifications and equivalents falling within the technical scope of the present invention.

For example, a layer other than the antistatic layers 22a and 22b may be additionally formed on the plastic film 21. [

(Example)

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]

1. Preparation of substrate (formation of antistatic layer)

Soluble methylol melamine and / or a water-soluble methylol melamine and / or a water-soluble methylol melamine and / or a water-soluble methylol melamine and / or a water-soluble methylol melamine and / or a water-soluble methylol melamine were dispersed in a diluting liquid (Chukyo-Yushi Shahe, product name: "S- (Product name " P-795 ", solid content: 70.0% by mass) consisting of water, a melamine compound solution made of water (Chukyo Yushi Co., %) Was further mixed with a mixed solvent of water and isopropyl alcohol (ratio by mass: 1: 1) and diluted to a solid content of 0.6% by mass to obtain a coating solution for a composition for an antistatic layer.

On one surface (the surface located on the pressure-sensitive adhesive layer side) of the polyethylene terephthalate (PET) film (Doreisha Chemical Co., Ltd., product name " PET75U48 ", thickness: Was coated with a knife coater and then heat-treated at 130 캜 for 60 seconds to form a first antistatic layer having a thickness of 50 nm. A second antistatic layer having a thickness of 50 nm was formed on the other surface of the PET film in the same manner as above except that the composition ratio of the composition for the antistatic layer was changed to form the first antistatic layer / / Second antistatic layer was obtained.

2. Manufacture of protective sheet

100 parts by mass of an addition reaction type silicone resin (Shin-Etsu Chemical Co., Ltd., product name: KS-847H) as a subject of a silicone-based pressure-sensitive adhesive and 10 parts by mass of silicone resin (Dow Corning Toray, product name "SD-4584" , And 2 parts by mass of a platinum catalyst (Dow Corning Toray, product name: "SRX 212 CATALYST") were mixed and diluted with methyl ethyl ketone, which was used as a coating liquid for a silicone-based pressure sensitive adhesive.

On the surface of the base material obtained in the above step 1, the coating liquid of the silicone-based pressure-sensitive adhesive was coated on the side of the first antistatic layer side with a knife coater and then heat-treated at 130 캜 for 1 minute to form a pressure- . Next, a release sheet (product name: " PET25T-100 (WJ) ", thickness: 25 mu m) comprising an antistatic layer (a third antistatic layer and a fourth antistatic layer) formed on both surfaces of a PET film Was adhered to the pressure-sensitive adhesive layer such that the side of the release sheet facing the third antistatic layer was in contact with the pressure-sensitive adhesive layer to obtain a protective sheet.

[Examples 2 to 6 and Comparative Examples 1 to 2]

A protective sheet was produced in the same manner as in Example 1 except that the plastic film and the release sheet were changed to those shown in Table 1. As the base materials of Comparative Examples 1 and 2, a PET film (plastic film) without an antistatic layer was used, and as a release sheet of Example 3 and Comparative Example 1, a PET film (support) without an antistatic layer was used.

[Test Example 1] (Measurement of surface resistivity)

The surface of the substrate used in Examples and Comparative Examples on the side of the pressure-sensitive adhesive layer and the surface on the opposite side (the front surface side of the protective sheet) and the side of the pressure-sensitive adhesive layer side of the release sheet and the surface on the opposite side (the back surface side of the protective sheet) According to K6911, the surface resistivity was measured. Specifically, a base material or a release sheet (100 mm x 100 mm) was prepared by using a resistivity meter (Mitsubishi Analyteksha, product name: "Hiesta UP MCP-HT450 type") under an environment of 23 ° C. and a relative humidity of 50% (Ω / sq) of each surface after a voltage of 100 V was applied for 10 seconds. The results are shown in Table 1. The surface resistivity of both surfaces of the base material (no antistatic layer) used in Comparative Examples 1 and 2 and the surface resistivity of both surfaces of the release sheet (no antistatic layer) used in Example 3 and Comparative Example 1 exceeded the measurement limit Respectively.

[Test Example 2] (Measurement of haze value)

The haze value (%) of the substrate used in Examples and Comparative Examples was measured in accordance with JIS K7136: 2000 using a haze meter (product name: "NDH7000" manufactured by Nippon Denshoku Chemical Co., Ltd.). The results are shown in Table 1. In addition, the release sheet was peeled from the protective sheet prepared in Examples and Comparative Examples, and the haze value (%) of the obtained laminate was measured in the same manner. The results are shown in Table 2.

[Test Example 3] (Measurement of surface roughness)

(Unit: nm) of the surface (119.8 占 퐉 占 91.2 占 퐉) of the pressure-sensitive adhesive layer side of the plastic film used in Examples and Comparative Examples and the surface (119.8 占 91.2 占 퐉) of the pressure- (Manufactured by Veeco Co., Ltd., product name: " surface shape measuring device ") according to JIS B601: 2001 in terms of a height (Rp; unit nm), a maximum height WYKO NT110 "). At this time, the measurement conditions PSI and the magnification were 50 times, and the average value of 10 measurement points was taken as the value of the surface roughness. The results are shown in Table 1.

[Test Example 4] (Evaluation of adhesive surface)

The release sheet was peeled from the protective sheet prepared in Examples and Comparative Examples, and the protective sheet was fixed in a state in which the exposed pressure-sensitive adhesive layer was exposed.

The surface shape (50 mm x 50 mm) of the pressure-sensitive adhesive layer (pressure-sensitive adhesive surface) was measured in accordance with JIS B601: 2001 using a light interference microscope (product name: "surface shape measurement device WYKO NT110" manufactured by Veeco). At this time, the measurement conditions were VSI and magnification 2.5 times. On the basis of the obtained measurement image, the evaluation of the adhesion surface (citron outer surface) was performed based on the image shown in Fig. In addition, the measurement image between? And? Was evaluated as?. The results are shown in Table 2.

[Test Example 5] (pressure-sensitive adhesive layer vs. voltage)

The protective sheet prepared in Examples and Comparative Examples was cut into 45 mm x 45 mm, and a release sheet was peeled off as a sample. The sample was placed on the turntable of an electrification attenuation meter (product name: "STATIC HONESTMETER", product of Shishido Seiden KK) under an environment of 23 ° C. and a relative humidity of 50% such that the pressure sensitive adhesive layer side was up. Next, the turntable was rotated at 1550 rpm, a voltage of 10 kV was applied at a position of 2.0 cm from the exposed surface of the pressure sensitive adhesive layer, and a voltage of 2.0 cm from the exposed surface of the pressure sensitive adhesive layer after 60 seconds of application Layer voltage; V) was measured. The results are shown in Table 2.

[Test Example 6] (Peeling Voltage)

The protective sheet prepared in Examples and Comparative Examples was cut into a size of 25 mm x 100 mm and used as a sample. The release sheet was peeled off from the sample by manual operation at a peeling rate of 2.0 m / min under an environment of 23 ° C and a relative humidity of 50%, and after 5 seconds of peeling, a static electricity meter (product name: FMX-003 ) Was used to measure the electrostatic potential (peeling electromotive force: V) at a position 2.0 cm from the exposed surface of the pressure-sensitive adhesive layer. From the measurement results, the peeling electrification voltage on the surface of the pressure-sensitive adhesive layer was evaluated based on the following criteria. The results are shown in Table 2.

5: Peeling voltage is less than 50V

4: peeling voltage is 50V or more, less than 100V

3: Peeling voltage is over 100V, less than 150V

2: peeling voltage is 150V or more, less than 200V

1: Peeling voltage is 200V or more and less than 1000V

[Test Example 7] (Evaluation of substrate adhesion property)

The release sheet was peeled from the protective sheet prepared in Examples and Comparative Examples, and a cross cut (30 mm x 30 mm) was inserted into the pressure-sensitive adhesive layer with a cutter knife. Then, the pressure-sensitive adhesive layer in the cut portion was rubbed with a finger to confirm the degree of detachment of the pressure-sensitive adhesive layer, and the adhesion of the base material was evaluated according to the following criteria. The results are shown in Table 2.

Good: The pressure-sensitive adhesive layer is not detached from the substrate, and good adhesion is maintained

DELTA: Part of the pressure-sensitive adhesive layer was detached from the base material, but a certain degree of adhesion was maintained

X: The whole pressure-sensitive adhesive layer was detached from the base material, and the lack of adhesion

[Table 1]

[Table 2]

As is clear from Table 2, the protective sheet produced in the Examples was excellent in antistatic property and also had excellent adhesion to the base material of the pressure-sensitive adhesive layer.

The protective sheet according to the present invention is suitable as a protective sheet used in processes such as processing, assembling, and inspection of OLED devices.

1: protective sheet 2: substrate
21: plastic film 22a: first antistatic layer
22b: second antistatic layer 3: pressure-sensitive adhesive layer
4: peeling sheet 41: support
42a: third antistatic layer 42b: fourth antistatic layer

Claims (10)

A protective sheet for protecting a device,
A plastic film, a substrate having an antistatic layer formed on at least one side of the plastic film,
A pressure-sensitive adhesive layer laminated on the substrate so as to be in contact with the antistatic layer
Respectively,
Wherein the pressure-sensitive adhesive layer comprises a silicone-based pressure-
Wherein the protective sheet is a sheet. The method according to claim 1,
Wherein the surface roughness of the surface of the plastic film on the side of the pressure-
The maximum peak height (Rp) is 200 nm or less,
The maximum height (Rz) is 300 nm or less,
The maximum cross-sectional height (Rt)
Wherein the protective sheet is a sheet. The method according to claim 1,
Wherein an antistatic layer is formed on the other surface side of the plastic film. The method according to claim 1,
A peeling sheet is laminated on a surface of the pressure-sensitive adhesive layer opposite to the substrate,
Wherein the release sheet comprises a support and an antistatic layer formed on at least one side of the support
Wherein the protective sheet is a sheet. The method according to claim 1,
And the haze value of the protective sheet from which the release sheet is removed is 5% or less. The method according to claim 1,
The surface resistivity of the surface of the base material on the side of the pressure-sensitive adhesive layer when a voltage of 100 V is applied to the base material for 10 seconds under an environment of 23 캜 and a relative humidity of 50% is 1 10 ⁵ Ω / And 1 × 10 ⁹ Ω / sq or less. The method according to claim 1,
The surface resistivity of the surface of the base material opposite to the pressure-sensitive adhesive layer when a voltage of 100 V was applied to the base material for 10 seconds under an environment of 23 캜 and 50% relative humidity was 1 × 10 ⁷ Ω / sq or more and 5 x 10 < ¹¹ > / sq or less. 5. The method of claim 4,
The surface resistivity of the surface of the release sheet on the side of the pressure-sensitive adhesive layer when applied to the release sheet at a voltage of 100 V for 10 seconds under an environment of 23 캜 and 50% relative humidity is 1 × 10 ⁷ Ω / sq or more and 1 x 10 < ¹¹ > / sq or less. 5. The method of claim 4,
The surface resistivity of the surface of the release sheet opposite to the pressure-sensitive adhesive layer when a voltage of 100 V was applied to the release sheet for 10 seconds under an environment of 23 캜 and a relative humidity of 50% ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less. 10. The method according to any one of claims 1 to 9,
Wherein the device is a flexible device.

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