TW201836849A - Protection plate having a substrate 2 and an adhesive layer 3 that is laminated on the substrate - Google Patents

Abstract

A protection plate has an adhesive layer having excellent heat resistance when a voltage of a peeling tape is kept at a low level in order to ensure good substrate adhesion of the adhesive layer. A protection plate 1 is characterized by being used as a protection plate 1 for protecting a device and including: a substrate 2 having a plastic film 21 and a charge preventing layer 22a formed on at least one side of the plastic film 21; and an adhesive layer 3 that is laminated on the substrate 2 in a way of being in contact with the charge preventing layer 22a. The adhesive layer 3 is made of a silicone resin-based adhesive.

Description

   Protection plate   

The present invention relates to a protective sheet that can be used for a protective device.

Previously, in devices such as optical components and electronic components, in order to prevent surface injuries during processing, assembly, and inspection steps, a protective plate formed of a plastic film and an adhesive layer was sometimes adhered to the surface of the device. sheet. This protection sheet is peeled from the device when protection is not required, and static electricity may be generated due to peeling and charging at this time.

If static electricity occurs, garbage or dust in the air will adhere to the device, causing the device to malfunction. Therefore, in order to avoid the occurrence of static electricity, it is required to provide an antistatic property to the adhesive layer of the protective sheet.

A protective sheet having an antistatic property, for example, in Patent Document 1, discloses a surface protective film including: a substrate having a first surface and a second surface; an antistatic layer provided on the first surface of the substrate; and On the second surface of the substrate, an adhesive layer formed of an adhesive composition.

[Leading technical literature]

[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2016-135592

However, in recent years, as an optical member, the movement from a liquid crystal device to an organic light emitting diode (OLED) device has become active. In addition, research into flexible OLED devices (hereinafter sometimes referred to as "flexible OLED devices") has also become active. This flexible OLED device is different from liquid crystal devices and ordinary OLED devices in that it is soft, and it is difficult to peel off the flexible OLED device when using the previous protective sheet. In addition, the material is more between the protective sheet and the protective sheet. Easily peeled and charged. Although the protective sheet described in Patent Document 1 attempts to reduce the peeling band voltage by the order of kV, considering flexible OLED devices, it is necessary to reduce the peeling band voltage by the order of V.

In addition, in the inspection step of the OLED device, it is sometimes exposed to high temperature conditions. The adhesive layer used for the protective plate of the OLED device is required to exhibit a stable adhesive force during or after inspection at a high temperature. That is, the protective sheet used for the above-mentioned application requires heat resistance.

Furthermore, when the protective sheet is peeled from the adherend as described above, it is necessary that the adhesive does not remain on the adherend side. That is, the adhesive layer of the protective sheet needs to have good adhesion to the substrate.

The present invention has been made in view of the above-mentioned conditions, and provides a protective plate which can suppress the peeling voltage at a low level, has excellent heat resistance of the adhesive layer, and can ensure good substrate adhesion of the adhesive layer. Film as the target.

To achieve the above object, firstly, the present invention provides a protective sheet, which is a protective sheet for protecting a device, and is characterized in that it includes a base material having a plastic film and at least one of the plastic films formed on the substrate. An antistatic layer on the surface side; and an adhesive layer, which is laminated on the base material layer so as to be connected to the antistatic layer, and the adhesive layer is formed of a silicone resin adhesive (Invention 1) .

In the above invention (Invention 1), at least between the plastic film and the adhesive layer, there is a charge preventing layer, and the peeling voltage can be suppressed to a low level. Therefore, it is not necessary to add an antistatic agent to the adhesive layer, and it is possible to ensure good substrate adhesion of the adhesive layer. In addition, since the silicone resin-based adhesive has stable adhesion even at high temperatures, the adhesive layer formed from the silicone resin-based 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 adhesive layer has a maximum peak height (Rp) of 200 nm or less, a maximum height (Rz) of 300 nm or less, and a maximum cross-sectional height (Rt) ) Is preferably 500 nm or less (Invention 2).

In the above invention (Inventions 1, 2), it is preferable that an antistatic layer is also 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 adhesive layer opposite to the substrate, and the release sheet includes: a support; and at least one of the support formed. The antistatic layer on the surface is preferably (Invention 4).

In the above inventions (Inventions 1 to 4), the haze value of the protective sheet except for the release sheet is preferably 5% or less (Invention 5).

In the above invention (Inventions 1 to 5), when the substrate is applied with a voltage of 100 V for 10 seconds under an environment of 23 ° C. and a relative humidity of 50%, the surface resistance of the surface of the adhesive layer side of the substrate is The ratio is preferably 1 × 10 ⁵ Ω / sq or more and 1 × 10 ⁹ Ω / sq or less (Invention 6).

In the above invention (Inventions 1 to 6), when a voltage of 100V is applied to the substrate for 10 seconds under an environment of 23 ° C and 50% relative humidity, the surface of the surface of the substrate opposite to the adhesive layer is applied. The specific resistance is preferably 1 × 10 ⁷ Ω / sq or more and 5 × 10 ¹¹ Ω / s or less (Invention 7).

In the above-mentioned invention (Invention 4), when a voltage of 100 V is applied to the release sheet for 10 seconds under an environment of 23 ° C and a relative humidity of 50%, the surface resistivity on the surface of the adhesive layer side of the release sheet is It is preferably 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / s or less (Invention 8).

In the above-mentioned invention (Invention 4), when a voltage of 100 V is applied to the release sheet for 10 seconds under an environment of 23 ° C and 50% relative humidity, the surface of the surface of the release sheet opposite to the adhesive layer The specific resistance is preferably 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / below (Invention 9).

In the above inventions (Inventions 1 to 9), the device is preferably a flexible device (Invention 10).

With regard to the protective sheet of the present invention, the peeling voltage can be suppressed to a low level, the heat resistance of the adhesive layer is excellent, and the good substrate adhesion of the adhesive layer can be ensured.

1‧‧‧ protection plate

2‧‧‧ substrate

21‧‧‧plastic film

22a‧‧‧The first anti-charge layer

22b‧‧‧Second electrification prevention layer

3‧‧‧ Adhesive layer

4‧‧‧ peeling sheet

41‧‧‧ support

42a‧‧‧3rd charge prevention layer

42b‧‧‧ 4th charge prevention layer

FIG. 1 is a cross-sectional view of a protective sheet according to an embodiment of the present invention.

FIG. 2 is a diagram (color) showing an evaluation standard image of a test example for evaluation of an adhesive surface.

[Forms for Implementing Invention]

Hereinafter, embodiments of the present invention will be described.

The protective sheet according to an embodiment of the present invention is mainly used to protect the device and prevent the surface of the device from being injured during steps such as processing, assembly, and inspection of the device.

The protective sheet according to this embodiment includes a base material and an adhesive layer. The substrate includes: a plastic film; and an antistatic layer formed on at least one side of the plastic film, and an adhesive layer is laminated on the substrate so as to be in contact with the antistatic layer. The adhesive layer is formed of a silicone adhesive.

In the protective sheet according to this embodiment, by having at least an antistatic layer between the plastic film and the adhesive layer, the peeling voltage can be suppressed to a low level. Therefore, when the release sheet is peeled from the adhesive layer, when the protective sheet is stuck to the device, or when the protective sheet is peeled from the device, it is possible to suppress the adhesion of garbage or dust in the air due to static electricity to the device. In addition, even when the device to be adhered is a flexible OLED device, the above-mentioned effects can be obtained, and damage to the flexible OLED device by static electricity can be prevented.

In addition, the silicone resin-based adhesive is easy to be made slightly adhesive, and is excellent in re-peelability. Therefore, the protective sheet of this embodiment can be smoothly peeled off by a flexible flexible device such as a flexible OLED device.

Furthermore, compared with acrylic adhesives, the silicone resin-based adhesives have stable adhesion at high temperatures and excellent heat resistance. Therefore, regarding the protective sheet of this embodiment in which the adhesive layer is made of a silicone resin adhesive, the device such as an OLED device to which the protective sheet is pasted, even when inspected at a high temperature (for example, 90 to 150 ° C). It is possible to prevent the adhesive force from significantly increasing, and to peel the protective sheet from the adherend without any problem.

In addition, the protective sheet of the present embodiment is excellent in antistatic property by having the antistatic layer between the plastic film and the adhesive layer as described above, so it is not necessary to add an antistatic agent to the adhesive layer. The adhesive layer formed by adding a general antistatic agent to the silicone resin-based adhesive will reduce the adhesiveness of the substrate. However, in the protective sheet of this embodiment, such problems can be avoided and adhesion can be ensured. Good substrate adhesion of the agent layer. Therefore, the protective sheet according to this embodiment has high stability and reliability as a product, and also, when the protective sheet is peeled from the adherend, it is possible to prevent the adhesive from remaining on the adherend side.

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

As shown in FIG. 1, a protective sheet 1 according to this embodiment includes a base material 2, an adhesive layer 3, and a release sheet 4. The substrate 2 includes: a plastic film 21; and a first electrification preventing layer 22a formed on a surface of the adhesive film 3 side of the plastic film 21 (a lower surface in FIG. 1); The second antistatic layer 22b on the surface opposite to the adhesive layer 3 (the upper surface in FIG. 1) is preferable. In addition, the release sheet 4 includes: a support 41; and a third electrification preventing layer 42a formed on a surface (a surface on the upper side in FIG. 1) on the adhesive layer 3 side of the support 41, and further has The fourth electrification preventing layer 42b of the surface of the support 41 opposite to the adhesive layer 3 (the surface on the lower side in FIG. 1) is particularly preferable. The adhesive layer 3 is laminated on the base material 2 so as to be in contact with the first antistatic layer 22 a of the base material 2. In the release sheet 4 of this embodiment, the third electrification preventing layer 42a of the release sheet 4 is laminated on the adhesive layer 3 so that the third electrification preventing layer 42a is in contact with the adhesive layer 3.

The peeling sheet 4 is used to protect the adhesive layer 3 until the protective sheet 1 is used, and is peeled and removed when the protective sheet 1 is used. Regarding the protective sheet 1 of this embodiment, the peeling sheet 4 may be omitted.

In addition, in this embodiment, the first electrification preventing layer 22a of the base material 2 is an essential element, the second electrification preventing layer 22b of the base material 2, the third electrification preventing layer 42a and the fourth prevention of the release sheet 4. The charging layer 42b is not necessary, and can be omitted independently. However, if the second electrification preventing layer 22b of the base material 2 and the third electrification preventing layer 42a and the fourth electrification preventing layer 42b of the sheet 4 are present, one or two or more layers can be provided to protect the Better charging prevention.

In addition, one of the preferred usage patterns of the protective sheet 1 may be that the protective sheet 1 is sent out by the winding roll of the protective sheet 1, the peeling sheet 4 is peeled off, and the exposed adhesive layer 3 is It is equipped with flexible OLED device, conveying and processing. In the aforementioned sending step, in order to prevent electrification, it is preferable to provide at least any one of the second electrification preventing layer 22b and the fourth electrification preventing layer 42b, and it is more preferable to provide both. In addition, in order to prevent the electrification in the peeling step of the release sheet 4 described above, it is preferable to add a third electrification preventing layer 42a connected to the adhesive layer 3 in addition to the first electrification preventing layer 22a.

Each component

(1) Substrate

(1-1) Plastic film

The plastic film 21 is not particularly limited. When the adherend is an OLED device, the plastic film 21 is preferably one having high transparency. Since the light emission inspection of the OLED device is performed at a stricter level than the light emission inspection of the liquid crystal device, the protective sheet 1 is required to have higher transparency. At this time, it is preferable that the plastic film 21 does not contain a filler. In addition, when the adherend is an OLED device, the plastic film 21 preferably has a high temperature (for example, 90 to 150 ° C.) heat resistance applied to the inspection of the OLED device.

Examples of the plastic film 21 include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyimide, polyetherimide, and polycarbonate. Plastic films formed from resins such as esters, polymethylpentene, polyphenylene sulfide, and liquid crystal polymers are preferred. The films may be formed as a single layer, or a plurality of layers of the same or different types may be laminated. Among the above, a polyethylene terephthalate film is particularly preferred in terms of heat resistance, transparency, and cost.

In addition, the plastic film may contain additives such as a filler, a heat resistance improver, and an ultraviolet absorber within a range that does not impair the effects of the embodiment described above.

For the purpose of improving the adhesion with the first antistatic layer 22a and / or the second antistatic layer 22b to the plastic film 21, a surface treatment by an oxidation method or a primer may be applied as desired. deal with. 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, ozone, and an ultraviolet irradiation treatment. These surface treatment methods can be appropriately selected according to the type of the plastic film 21.

The thickness of the plastic film 21 is preferably 25 μm or more, more preferably 38 μm or more, and further preferably 50 μm or more in consideration of heat resistance and workability of adhesion and peeling. When the device to be protected is a flexible device, from the viewpoint of workability of sticking and peeling, it is particularly preferably 50 μm or more. On the other hand, considering the workability and cost of sticking and peeling, the thickness is preferably 150 μm or less, particularly 125 μm or less, and further preferably 100 μm or less.

The surface roughness of the surface on the side of the adhesive layer 3 (the side of the first antistatic layer 22a) of the plastic film 21 is preferably an arithmetic mean roughness (Ra) of 10 nm or less, more preferably 7 nm or less, and particularly 5 nm or less Preferably, it is more preferably 3 nm or less. Thereby, the haze value of the plastic film 21, especially the external haze can be reduced, and the transparency can be made higher. In addition, the surface roughness in this specification is calculated | required by the roughness curve measured using the light interference microscope in accordance with JIS B0601: 2001. The details are shown in the test examples. In addition, 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 an easily-adhesive layer.

The lower limit 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.

In addition, the surface roughness of the surface on the side of the adhesive layer 3 (the side of the first charge prevention layer 22a) of the plastic film 21 is 200 nm or less with the maximum peak height (Rp) and 300 nm or less with the maximum height The cross-section height (Rt) is preferably 500 nm or less. When the plastic film 21 satisfies the above requirements, the adhesive surface of the adhesive layer 3 (adhesive layer, surface in contact with the adherend) can be suppressed from being orange peel, and the see-through property of the protective plate 1 adhered to the adherend can be suppressed. very high. Therefore, for example, the light emission 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 suppressing orange peel, the maximum peak height (Rp) is preferably 200 nm or less, particularly preferably 150 nm or less, and further preferably 100 nm or less. From the viewpoint of suppressing orange peel, the maximum height (Rz) is preferably 300 nm or less, particularly preferably 200 nm or less, and further preferably 100 nm or less. From the viewpoint of suppressing orange 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, and further preferably 200 nm or less. The lower limit 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 of the maximum height (Rz) is not particularly limited, but is preferably 5 nm or more, particularly preferably 10 nm or more, and further preferably 20 nm or more. The lower limit of the maximum cross-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) Anti-charge layer

The first electrification preventing layer 22a and the second electrification preventing layer 22b are not particularly limited as long as they are formed of a material which can impart desired antistatic properties to the plastic film 21 and has transparency. Such an antistatic layer 22a, 22b is preferably a layer formed of a composition for an antistatic layer containing a conductive polymer and a binder resin, for example.

The conductive polymer may be selected from any of the conventionally known conductive polymers and is suitably selected for use. Among them, polythiophene-based, polyaniline-based, or polypyrrole-based conductive polymers are preferred. The conductive polymer may be used singly or in combination of two or more kinds.

Examples of the polythiophene-based conductive polymer include polythiophene, poly (3-alkylthiophene), poly (3-thiophene-β-ethanesulfonic acid), polyalkylene dioxythiophene, and polystyrene sulfonic acid. (PSS) mixtures (including doped) and the like. Among these, a mixture of polyalkylene dioxythiophene and polystyrene sulfonate is preferable. Examples of the polyalkylene dioxythiophene include poly (3,4-ethylenedioxythiophene) (PEDOT), poly (propylene dioxythiophene), and poly (ethylidene / oxypropyl) dioxythiophene. Among them, poly (3,4-ethylenedioxythiophene) is preferred. That is, among the above, a mixture of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid (PSED-doped PEDOT) is particularly preferred.

Examples of the polyaniline-based conductive polymer include polyaniline, polymethylaniline, and polymethoxyaniline. Examples of the polypyrrole-based conductive polymer include polypyrrole, poly3-methylpyrrole, and poly3-octylpyrrole.

The content of the conductive polymer in the composition for preventing a charged layer is preferably from 0.1 to 30% by mass, particularly from 0.2 to 20% by mass, and even more preferably from 0.3 to 10% by mass. As long as the content of the conductive polymer is within the above range, good antistatic properties can be obtained, and the strength of the antistatic layer formed from the antistatic layer composition can be made sufficient.

The binder resin that can be used in the composition for preventing an electrification layer preferably contains at least one 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 UV-curable compounds. In order to achieve UV-curability, the solvent needs to be replaced from an aqueous system to an organic solvent system. Therefore, from the viewpoint of the number of steps and cost, the resin is thermosetting. Compounds are preferred. Among the above, a thermosetting polyester resin is preferred because of its high adhesion to plastic films, and a reactive group that reacts with a bridging agent, for example, a polyester resin such as a hydroxyl group is particularly preferred.

The composition for an antistatic layer may contain a bridging agent, a smoothing agent, an antifouling agent, etc. in addition to the above components.

The bridging agent may be any resin that can bridge the resin. For example, if the resin has a hydroxyl group as a reactive group, an isocyanate-based bridging agent, an epoxy-based bridging agent, an amine-based bridging agent, a melamine-based bridging agent, or the like is preferably used.

The total amount of the bridging agent is preferably 1 to 50 parts by mass, more preferably 5 to 40 parts by mass, and even more preferably 10 to 30 parts by mass relative to 100 parts by mass of the binder resin.

As the smoothing agent, for example, a dimethylsiloxane compound, a fluorine compound, a surfactant, or the like can be used. From the viewpoint of the adhesion of the adhesive layer 3, it is preferable to use a surfactant in the first antistatic layer 22a. By including a smoothing agent in the composition for an antistatic layer, the smoothness of the antistatic layers 22a and 22b can be improved, and the transparency of the base material 2 can be made higher.

The content of the smoothing agent in the composition for preventing a charged layer is preferably from 0.1 to 10% by mass, particularly from 0.2 to 5% by mass, and further preferably from 0.5 to 3% by mass.

In consideration of the thickness of the first antistatic layer 22a and the second antistatic layer 22b, the antistatic property is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more. The thickness of the first antistatic layer 22a and the second antistatic layer 22b is preferably 200 nm or less from the viewpoint of strength and cost, particularly preferably 150 nm or less, and further preferably 100 nm or less.

(1-3) Physical properties of substrate

(1-3-1) Surface resistivity

When a voltage of 100V is applied to the substrate 2 for 10 seconds at 23 ° C and a relative humidity of 50%, the surface of the adhesive layer 3 side of the substrate 2 (the first antistatic layer 22a is opposite to the plastic film 21). The upper surface resistivity is preferably 1 × 10 ⁹ Ω / sq or less, particularly preferably 5 × 10 ⁸ Ω / sq or less, and more preferably 1 × 10 ⁸ Ω / sq or less. By setting the upper limit value of the surface resistivity as described above, the peeling band voltage can be effectively suppressed to a low level. Therefore, when the peeling sheet 4 is peeled from the adhesive layer 3 or when the protective sheet 1 is peeled from the device, static electricity can be effectively suppressed. In addition, the lower limit value of the surface resistivity is not particularly limited, but is usually preferably 1 × 10 ⁵ Ω / sq or more, particularly preferably 5 × 10 ⁵ Ω / sq or more, and further preferably 1 × 10 ⁶ Ω / sq or more Better.

In addition, when a voltage of 100 V is applied to the substrate 2 for 10 seconds under an environment of 23 ° C. and a relative humidity of 50%, the surface of the substrate 2 opposite to the adhesive layer 3 (the contact of the second antistatic layer 22 b and The upper surface resistivity of the plastic film 21) is preferably 5 × 10 ¹¹ Ω / sq or less, more preferably 1 × 10 ¹¹ Ω / sq or less, and further 5 × 10 ¹⁰ Ω / sq The following is better. By setting the upper limit value of the surface resistivity as described above, it is possible to more effectively suppress the occurrence of static electricity when the protective sheet 1 is sent out from the winding roll of the protective sheet 1. In addition, the lower limit value of the surface resistivity is not particularly limited. Usually, it is preferably 1 × 10 ⁷ Ω / sq or more, particularly preferably 5 × 10 ⁷ Ω / more, and further preferably 1 × 10 ⁸ Ω / sq or more. good.

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

(1-3-2) Haze value

The haze value of the substrate 2 is preferably 5% or less, more preferably 3% or less, and further preferably 1% or less. By setting the haze value of the base material 2 as described above, the transparency of the protective sheet 1 adhered to the adherend can be made high. By forming the plastic film 21 with a plastic film not containing a filler, the above-mentioned haze value can be easily achieved. In addition, if the arithmetic mean roughness (Ra) of the plastic film 21 is in the above range, the haze value can be more easily achieved. The lower limit of the haze value is not particularly limited, but is particularly preferably 0%. Here, the haze value in this specification is a value measured according to JIS K7136: 2000.

(2) Adhesive layer

(2-1) Materials

The adhesive layer 3 is formed of a silicone adhesive. The silicone resin-based adhesive can be selected to be adhered to the object to be protected (device) and to be peeled from the object. For example, when the adherend is a flexible device such as a flexible OLED device, the protective sheet 1 is easily peeled off by the flexible device, and a micro-adhesive silicone adhesive having excellent re-peelability is selected as: good.

The silicone-based adhesive may be a condensation-type silicone adhesive or an addition-reactive silicone adhesive. From the standpoint of re-peelability, an addition-reactive silicone adhesive is preferred.

Addition reaction type siloxane resin-based adhesive containing a first polydimethylsiloxane having at least two alkenyl groups in one molecule and a second polydimethylsiloxane having at least two hydrogen silicon groups in one molecule The addition-reaction type silicone resin obtained based on a siloxysilane is preferably used as a main component, and further, a silicone resin is particularly preferable.

Examples of the alkenyl group contained in the first polydimethylsiloxane include vinyl, allyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl. Valence hydrocarbon groups, with vinyl being particularly preferred.

The content of the alkenyl group (the ratio of the number of alkenyl groups to the number of methyl groups bonded to silicon atoms) in the first polydimethylsiloxane is preferably 0.005 to 0.1 mole%, and 0.01 to 0.05 mole% is particularly preferred. The alkenyl group is preferably at both ends of the molecular chain, and may also be at a side chain. By containing at least two alkenyl groups in one molecule of the first polydimethylsiloxane, and the content of the alkenyl groups is within the above range, a bridging structure with a high bridging density can be formed, and an adhesive layer having excellent re-peelability 3 is obtained .

The degree of polymerization (the number of siloxane bonds) of the first polydimethylsiloxane is preferably 200 to 5,000, and particularly preferably 500 to 3,000. In addition, the content of the hydrosilyl group in the second polydimethylsiloxane is preferably 2 to 300 in one molecule, and particularly preferably 4 to 200. The degree of polymerization of the second polydimethylsiloxane is preferably 50 to 2,000, and particularly preferably 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, and particularly preferably 0.1 to 10 parts by mass. When the content of the second polydimethylsiloxane with respect to each functional group and the blending ratio of the first polydimethylsiloxane are within the above ranges, the first polydimethylsiloxane can be performed well. Addition of alkane with 2nd polydimethylsiloxane.

Furthermore, it is preferable that the first polydimethylsiloxane has no hydrosilyl group, and the second polydimethylsiloxane has no alkenyl group.

The weight average molecular weight of the first polydimethylsiloxane is preferably 20,000 to 1.3 million, and particularly preferably 300,000 to 1.2 million. The weight average molecular weight of the second polydimethylsiloxane is preferably 300 to 1400, and particularly preferably 500 to 1200. In addition, the weight average molecular weight in this specification is a standard polystyrene conversion value measured by the gel permeation chromatography (GPC) method.

As the silicone resin, for example, a monofunctional siloxane unit [(CH ₃ ) ₃ SiO _1/2 ] M unit and a tetrafunctional siloxane unit [(SiO _4/2 ] Q unit) can be used. MQ resin. The molar ratio of M units / Q units is preferably from 0.6 to 1.7. This silicone resin has the role of imparting adhesiveness to silicone adhesives.

The lower limit of the amount of the silicone resin to 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, and further preferably 5 parts by mass or more. By setting the lower limit value of the blending amount of the silicone resin to the above, a desired adhesive force can be obtained, and the protective sheet 1 can be prevented from being undesirably peeled off by 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, and further preferably 20 parts by mass or less. By setting the upper limit of the blending amount of the silicone resin to the above, it is possible to prevent the adhesive force from becoming too high, and to ensure the re-peelability of the protective sheet 1.

The addition reaction type silicone resin-based adhesive preferably contains a catalyst. The catalyst is not particularly limited as long as it can harden the addition reaction type silicone resin (addition reaction of the first polydimethylsiloxane and the second polydimethylsiloxane), among which platinum group metals Compounds are preferred. Examples of the platinum group metal compounds include fine particulate platinum, fine particulate platinum adsorbed on a carbon powder support, platinum chloride, alcohol-denatured platinum chloride, an olefin complex of platinum chloride, palladium, rhodium, etc. . By containing this catalyst, the curing reaction of the addition reaction type silicone resin can be performed more efficiently.

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

The silicone resin-based adhesive may contain various additives such as a bridging agent, a reaction inhibitor, and a silane coupling agent. On the other hand, the aforementioned silicone resin-based adhesive preferably does not contain an antistatic agent. Adding a general antistatic agent to the silicone resin-based adhesive may reduce the adhesiveness of the base material of the obtained adhesive layer 3, and the transparency of the adhesive layer 3 may be lower due to low compatibility. . However, as long as it is an antistatic agent that does not cause this abnormality, it may be added to a silicone resin-based adhesive.

(2-2) Thickness

From the viewpoint of adhesion, the thickness of the adhesive layer 3 is preferably 15 μm or more, particularly preferably 20 μm or more, and more preferably 25 μm or more. The thickness of the adhesive layer 3 is preferably 75 μm or less, particularly preferably 50 μm or less, and further preferably 30 μm or less from the standpoint of peelability.

(3) Peeling sheet

(3-1) Support

The support 41 is not particularly limited as long as it does not adversely affect the adhesive layer 3. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, and polymethylpentene can be used. Olefin film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene Vinyl acetate film, ionic polymer resin film, ethylene‧ (meth) acrylic copolymer film, ethylene‧ (meth) acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, Fluorine resin film, etc. In addition, such bridging films can also be used. Furthermore, such a laminated film may be used. Among the above, a polyethylene terephthalate film having excellent handleability is preferred.

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

(3-2) Anti-charge layer

The third antistatic layer 42a and the fourth antistatic layer 42b are not particularly limited as long as they are formed of a material capable of imparting desired antistatic properties to the plastic film 21. As such a material of the antistatic layers 42a and 42b, it is preferable to use the same material as the antistatic layers 22a and 22b of the base material 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 base material 2.

Here, as described above, in the protective sheet 1 according to the present embodiment, either or both of the third electrification preventing layer 42a and the fourth electrification preventing layer 42b may be omitted. However, when one is omitted, it is preferable to omit the fourth electrification preventing layer 42b. The presence of the third electrification preventing layer 42 a in contact with the adhesive layer 3 can effectively improve the electrification prevention property when the release sheet 4 is peeled from the adhesive layer 3.

(3-3) Physical properties of peeling sheet

(3-3-1) Surface resistivity

When a voltage of 100 V is applied to the release sheet 4 for 10 seconds at an environment of 23 ° C. and a relative humidity of 50%, the surface on the side of the adhesive layer 3 of the release sheet 4 (the third electrification preventing layer 42 a and the support) The surface resistivity of the surface on the opposite side of 41) is preferably 1 × 10 ¹¹ Ω / sq or less, particularly preferably 5 × 10 ¹⁰ Ω / s or less, and further preferably 1 × 10 ¹⁰ Ω / s or less. good. By setting the upper limit value of the surface resistivity as described above, when the release sheet 4 is peeled from the adhesive layer 3, the occurrence of static electricity can be well suppressed, and when the protective sheet 1 is adhered to the device, it can be more effectively Suppress air or dust from attaching to the device. In addition, the lower limit value of the surface resistivity is not particularly limited, but is usually preferably 1 × 10 ⁷ Ω / sq or more, particularly preferably 5 × 10 ⁷ Ω / s or more, and further preferably 1 × 10 ⁸ Ω / s. The above is better.

When a voltage of 100 V is applied to the release sheet 4 for 10 seconds at an environment of 23 ° C. and a relative humidity of 50%, the surface of the release sheet 4 opposite to the adhesive layer 3 (in the fourth charge prevention layer 42 b The surface resistivity of the surface on the side opposite to the support 41) is preferably 1 × 10 ¹¹ Ω / sq or less, more preferably 5 × 10 ¹⁰ Ω / s or less, and further preferably 1 × 10 ¹⁰ Ω / s s is preferably below. By setting the upper limit value of the surface resistivity as described above, it is possible to more effectively suppress the occurrence of static electricity when the protective sheet 1 is sent out from the winding roll of the protective sheet 1. In addition, the lower limit value of the surface resistivity is not particularly limited, and is preferably 1 × 10 ⁷ Ω / sq or more, particularly preferably 5 × 10 ⁷ Ω / s or more, and further preferably 1 × 10 ⁸ Ω / s or more. good.

(3-3-2) Surface roughness

The surface roughness of the surface on the side of the adhesive layer 3 (the side of the third charge prevention layer 42a) of the release sheet 4 is 100 nm or less in arithmetic mean roughness (Ra) and 1500 nm or less in the maximum peak height (Rp). The maximum height (Rz) is preferably 1500 nm or less, and the maximum cross-sectional height (Rt) is preferably 2,000 nm or less. When the release sheet 4 satisfies the above requirements, the orange peel of the adhesive surface of the adhesive layer 3 that is in close contact with the release sheet 4 can be more effectively suppressed, and the see-through property of the protective sheet 1 adhered to the adherend can be more effectively. high. Therefore, for example, the light emission 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 suppressing the orange peel of the adhesive layer 3, the arithmetic average 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 further preferably 1000 nm or less. The maximum height (Rz) is preferably 1500 nm or less, particularly preferably 1250 nm or less, and further preferably 1000 nm or less. The maximum cross-sectional height (Rt) is preferably 2000 nm or less, particularly preferably 1750 nm or less, and further preferably 1500 nm or less. The lower limit 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 of the maximum peak height (Rp) is not particularly limited, but is preferably 50 nm or more, particularly preferably 100 nm or more, and more preferably 200 nm or more. The lower limit of the maximum height (Rz) is not particularly limited, but is preferably 50 nm or more, particularly preferably 100 nm or more, and more preferably 200 nm or more. The lower limit value of the maximum cross-sectional height (Rt) is also not particularly limited, but is preferably 200 nm or more, particularly preferably 300 nm or more, and further preferably 400 nm or more.

(3-4) other

The surface of the release sheet 4 of the present embodiment that is in contact with the adhesive layer 3 is preferably not subjected to a release treatment, that is, there is no release agent layer. When the adhesive layer 3 is composed of a silicone resin adhesive composition, a fluorine-based release agent is usually used as a release agent layer. However, when a release agent layer formed of a fluorine-based release agent is provided, a fluorine component is transferred to the adhesive layer 3. In addition, the antistatic property or the adhesive force of the adhesive layer 3 may become unstable.

2. Manufacturing method of protective plate

(1) Manufacturing of substrates

After manufacturing the base material 2 of this embodiment, as an example, one surface of the plastic film 21 is coated with a coating liquid containing a composition for preventing an electrostatic charge layer and a desired solvent, and then dried. It hardens, and the 1st antistatic layer 22a is formed. In addition, the second surface of the plastic film 21 is coated with a coating liquid containing a composition for an antistatic layer and a desired solvent, and then dried and hardened to form a second antistatic layer 22b. The solvent is not particularly limited, and various materials can be used. For example, ether-based solvents, alcohol-based solvents, mixed solvents of alcohol-based solvents and pure water, and the like.

The application of the coating liquid for preventing the composition for the charged layer may be performed by a conventional method, for example, a gravure coating method, a bar coating method, a spray coating method, a spin coating method, a knife coating method, or a roll. The coating method and the die coating method may be performed.

After the coating liquid is applied, the coating film is preferably dried by heating. The heating temperature for heating and drying is preferably 70 to 140 ° C, and the heating time is preferably about 30 to 60 seconds.

(2) Manufacturing of peeling sheet

The release sheet 4 in this embodiment can be manufactured by the same method as the manufacturing method of the base material 2. That is, when the release sheet 4 is manufactured, as an example, one surface of the support 41 is coated with a coating solution containing a composition for preventing a charge and a desired solvent, and then dried to harden, A third antistatic layer 42a is formed. In addition, the other surface of the support 41 is coated with a coating liquid containing a composition for an antistatic layer and a desired solvent, and then dried to harden to form a fourth antistatic layer 42b.

(3) Manufacturing of protective plates

In the production of the protective sheet 1 according to this embodiment, as an example, a surface containing a silicone resin-based adhesive and a desired diluent is applied to a surface on the side of the first antistatic layer 22a of the substrate 2 according to a desired thinner. After the liquid is dried, it is hardened to form an adhesive layer 3.

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

The coating of the coating liquid of the silicone resin adhesive may be performed by a conventional method, for example, a wire rod coating method, a knife coating method, a roll coating method, a doctor blade coating method, a mold coating method, The gravure coating method may be performed. After the coating liquid is applied, the coating film is preferably dried by heating.

When the main agent of the silicone resin-based adhesive is an addition reaction type silicone resin-based adhesive, it is preferable that the coating film is thermally cured. The heating temperature at this time is preferably 80 to 180 ° C, and the heating time is preferably about 10 to 90 seconds.

After the adhesive layer 3 is formed as described above, the peeling sheet 4 is adhered to the adhesive layer 3 so as to be in contact with the third antistatic layer 42a to obtain the protective sheet 1.

Furthermore, in the above-mentioned manufacturing method, the adhesive layer 3 is formed on the base material 2, but it may be formed on the release sheet 4, and then the base material 2 is adhered on the adhesive layer 3.

3. Physical properties

(1) Haze value

The haze value of the laminated body (the laminated body of the base material 2 and the adhesive layer 3 in this embodiment) other than the release sheet 4 of the protective sheet 1 of this embodiment is preferably 5% or less It is more preferably 3% or less, particularly 2% or less, and further preferably 1% or less. By setting the haze value as described above, the transparency of the protective sheet 1 can be made higher. For example, the light emission inspection of the OLED device to which the protective sheet 1 is adhered can be performed without any problem. The lower limit of the haze value is not particularly limited, but is particularly preferably 0%.

In the protective sheet 1 of this embodiment, the haze value is easily achieved by forming the plastic film 21 with a plastic film not containing a filler. In addition, if the arithmetic mean roughness (Ra) of the plastic film 21 is in the above range, it is easier to achieve the above-mentioned haze value.

(2) Adhesive layer with voltage

Laminates other than the release sheet 4 of the protective sheet 1 according to this embodiment (a laminate of the base material 2 and the adhesive layer 3 in the present embodiment) under an environment of 23 ° C. and a relative humidity of 50%. ), Set on the turntable with the adhesive layer 3 exposed, while rotating the turntable, apply a voltage of + 10kV from the position of the adhesive layer 3 at a distance of 2.0cm (the voltage of the adhesive layer), below 2kV Preferably, it is more preferably 1.5 kV or less, and further preferably 1 kV or less. By setting the charging voltage of the adhesive layer as described above, when the peeling sheet 4 is peeled from the adhesive layer 3, static electricity is not easily generated when the protective sheet 1 is stuck to the device, or when it is peeled from the device, and the cause can be effectively suppressed. The static electricity causes dust or dust in the air to adhere to the device. The lower limit value of the voltage of the adhesive layer is not particularly limited, but 0V is preferred. The details of the method for measuring the voltage of the adhesive layer are shown in the test examples described later.

(3) Peeling voltage

In an environment of 23 ° C. and a relative humidity of 50%, the peeling sheet 4 was manually peeled from the adhesive layer 3 of the protective sheet 1 according to this embodiment at a peeling speed of 2.0 m / min. After a second, the electrostatic potential (peel-off voltage) at a position 2.0 cm from the exposed surface of the adhesive layer was measured, preferably 200 V or lower, particularly 150 V or lower, and even more preferably 100 V or lower. By setting the peeling voltage as described above, when the peeling sheet 4 is peeled off from the adhesive layer 3, static electricity is not easily generated, and it is possible to effectively suppress the adhesion of garbage or dust in the air due to static electricity to the device. The lower limit of the peeling-off voltage is not particularly limited, but is preferably 0V. The details of the measurement method of the peeling voltage are shown in the test examples described later.

4. Use

The protective sheet 1 according to this embodiment is mainly used for protecting the device during steps of processing, assembling, and inspecting the device to prevent the surface of the device from being injured. However, it should not be limited to that use.

The device to be protected by the protective sheet 1 may be, for example, an optical member or an electronic member. In this embodiment, a flexible device is preferred. In addition, a light emission inspection or request is made in a state where the protective sheet 1 is adhered. High temperature conditions are preferred. Among these, an OLED device is more preferable, and a flexible OLED device is particularly preferable.

The protective sheet 1 according to this embodiment includes the first antistatic layer 22a and further includes the second to fourth antistatic layers 22b, 42a, and 42b. Therefore, the peeling voltage can be suppressed to a low level (especially, On the order of V), it has excellent antistatic properties. Thereby, when the peeling sheet 4 is peeled off from the adhesive layer 3 and adhered to the device for protecting the sheet 1 or when it is peeled off from the device, static electricity is not easy to occur, and it is possible to suppress the attachment of garbage and dust caused by electrostatic air to the device. . In addition, since the protective sheet 1 according to this embodiment includes the second electrification preventing layer 22b and the fourth electrification preventing layer 42b, it is possible to suppress the occurrence of static electricity when the protective sheet 1 is sent out from the winding roll of the protective sheet 1. . On the other hand, since the adhesive layer 3 formed of a silicone resin-based adhesive is excellent in re-peelability, it can be easily peeled off by a flexible device such as an OLED device. In addition, since the adhesive layer 3 formed of a silicone resin-based adhesive has excellent heat resistance, even when the OLED device or the like to which the protective sheet 1 is adhered, the adhesive force can be suppressed from significantly increasing when inspected at a high temperature. The protective sheet 1 can be peeled off from the OLED device or the like without any problem. Furthermore, in the protective sheet 1 according to this embodiment, it is not necessary to add an antistatic agent to the adhesive layer 3 formed of a silicone resin-based adhesive in order to obtain antistatic properties, so the adhesive layer 3 is opposed to the substrate 2 Has excellent adhesion (substrate adhesion). As a result, the stability and reliability of the product are high. In addition, when the protective sheet 1 is peeled from the adherend, there is no risk that the adhesive layer 3 or the adhesive remains on the adherend side.

The embodiments described above are described for easy understanding of the present invention and are not intended to limit the description of the present invention. Therefore, each element disclosed in the above-mentioned embodiment includes all design changes or equivalents belonging to the technical scope of the present invention.

For example, a layer other than the antistatic layer 22a, 22b may be further formed on the plastic film 21.

[Example]

Hereinafter, the present invention will be described more specifically with examples and the like, but the scope of the present invention should not be limited to these examples and the like.

(Example 1)

1. Manufacture of substrate (prevention of the formation of a charged layer)

A diluent prepared by diluting dimethyl sulfene and water with a polyester resin containing water-soluble hydroxyl groups and PEDOT doped with PSS (manufactured by Nakakyo Oil Co., Ltd., product name "S-495", solid content 8.2 mass %), A melamine compound solution (manufactured by Nakakyo Oil Co., Ltd., product name "P-795", solid content 70.0% by mass) made of water-soluble methylol melamine and water, and a surfactant and water as a smoothing agent are mixed. An aqueous solution of the smoothing agent (manufactured by Nakakyo Oil and Fat Co., Ltd., product name "R-438", solid content 10.0% by mass), a mixed solvent of water and isopropanol (mass ratio 1: 1) was further added thereto, and diluted to a solid content 0.6% by mass to obtain a coating liquid of a composition for preventing an electrostatic charge layer.

On one side of the polyethylene terephthalate (PET) film (made by TORAY Co., Ltd., product name "PET75U48", thickness: 75 μm, without filler) on one side (the surface on the side of the adhesive layer) After coating the coating liquid of the composition for the anti-static layer with a knife coater, heat treatment was performed at 130 ° C. for 60 seconds to form a first anti-static layer with a thickness of 50 nm. In addition, 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 described above, except that the blending ratio of the composition for the antistatic layer was changed. Thus, a first antistatic layer / plastic film was obtained. / Second base material for preventing formation of a charging layer.

2. Manufacturing of protective plates

Addition of 100 parts by mass of a silicone resin as the main agent of a silicone resin-based adhesive (Shin-Etsu Chemical Industry Co., Ltd., product name "KS-847H"); 10 parts by mass of a silicone resin (TORAY‧DOWCORNING Company product, product name "SD-4584"); 2 parts by mass of platinum catalyst (TORAY‧DOWCORNING company product, product name "SRX 212 CATALYST") are mixed, diluted with methyl ethyl ketone, and this is used as a silicone resin adhesive Coating solution.

The surface of the first antistatic layer side of the substrate obtained in the above step 1 was coated with the coating solution of the silicone resin-based adhesive with a knife coater, and then heated at 130 ° C for 1 minute to form a thickness. 25 μm adhesive layer. Next, a release sheet (manufactured by Mitsubishi Resin Corporation, product name "PET25T-100 (WJ)" was formed by forming a charge prevention layer (a third charge prevention layer and a fourth charge prevention layer) on both surfaces of the PET film (support). ”, Thickness: 25 μm), and the surface of the third electrification preventing layer of the release sheet was adhered to the adhesive layer so that the protective sheet was obtained.

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

The protective film 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. In addition, as the substrates of Comparative Examples 1 and 2, PET films (plastic films) without a charge prevention layer were used, and the release sheets of Examples 3 and 1 were PET films (supports) without a charge prevention layer.

[Test Example 1] (Measurement of Surface Resistivity)

The surface on the adhesive layer side and the surface on the opposite side (surface side of the protective sheet) of the substrates of Examples and Comparative Examples, and the surface on the adhesive layer side of the release sheet and the opposite side (protection) The surface of the sheet) is measured on the surface resistivity in accordance with JIS K6911. Specifically, it was measured at 23 ° C and 50% relative humidity using a resistance meter (manufactured by ANALYTIC Corporation, product name "HIRESTA UP MCP-HT450") to measure the application to a substrate or a release sheet (100 mm × 100 mm) Surface resistivity (Ω / sq) of each surface after a voltage of 100 V for 10 seconds. The results are shown in Table 1. In addition, the surface resistivity of both surfaces of the base material (without a charge preventing layer) of Comparative Examples 1 and 2 and the surfaces of both surfaces of the release sheet (without a charge preventing layer) of Example 3 and Comparative Example 1 were used. The resistivity exceeds the measurement limit.

[Test Example 2] (Measurement of Haze Value)

The haze values (%) of the substrates used in the examples and comparative examples were measured in accordance with JIS K7136: 2000 using a haze meter (manufactured by Nippon Denshoku Industries, Inc., product name "NDH7000"). The results are shown in Table 1. Moreover, the peeling sheet was peeled from the protective sheet manufactured by the Example and the comparative example, and the haze value (%) of the obtained laminated body was measured similarly. The results are shown in Table 2.

[Test Example 3] (Measurement of surface roughness)

The arithmetic mean surface roughness (Ra) of the surface (119.8 μm × 91.2 μm) on the adhesive layer side of the plastic films of the Examples and Comparative Examples and the surface (119.8 μm × 91.2 μm) on the adhesive layer side of the release sheet was used. (Unit nm), maximum peak height (Rp; unit nm), maximum height (Rz; unit nm), and maximum cross-sectional height (Rt; unit nm), in accordance with JIS B601: 2001, using an optical interference microscope (manufactured by Veeco, Product name "surface shape measuring device WYKO NT110"). At this time, the measurement conditions were PSI and a magnification of 50 times, and the average value at 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 peeling sheet was peeled from the protective sheet manufactured in Examples and Comparative Examples, and the exposed adhesive layer was fixed in the exposed state.

The surface shape (50 mm × 50 mm) of the adhesive layer (adhesive surface) was measured in accordance with JIS B601: 2001 using a light interference microscope (manufactured by Veeco, product name "surface shape measuring device WYKO NT110"). At this time, the measurement conditions were VSI and 2.5 times magnification. Based on the obtained measurement image, the adhesion surface (orange peel) was evaluated using the image shown in FIG. 2 as a reference. The measurement images between ○ and × were evaluated as Δ. The results are shown in Table 2.

[Test Example 5] (Adhesive layer voltage)

The protective sheet manufactured in the examples and comparative examples was cut into 45 mm × 45 mm, and the peeled sheet was used as a sample. In a 23 ° C, 50% relative humidity environment, the sample was placed with the adhesive layer facing up on a turntable of a charged charge decay meter (manufactured by SHISHIDO Electrostatic Corporation, product name "STATIC HONESTMETER"). Next, the above-mentioned turntable was rotated at 1550 rpm, a voltage of 10 kV was applied from a position 2.0 cm away from the exposed surface of the adhesive layer, and after 60 seconds of application, a charged voltage (adhesion from a position 2.0 cm away from the exposed surface of the adhesive layer was measured) Agent layer with voltage; V). The results are shown in Table 2.

[Test Example 6] (Peel voltage)

The protective sheet manufactured in Examples and Comparative Examples was cut into 25 mm × 100 mm, and this was used as a sample. When the peeling sheet was peeled manually at 23 ° C and a relative humidity of 50% at a peeling rate of 2.0 m / min, 5 seconds after peeling, an electrostatic measuring device (manufactured by SIMICO JAPAN, product name "FMX" -003 "), and measured the electrostatic potential (peeling voltage; V) from a position 2.0 cm from the exposed surface of the adhesive layer. From the measurement results, the peeling voltage on the surface of the adhesive layer was evaluated on the following basis. The results are shown in Table 2.

5 ... Peel voltage below 50V

4 ... Peeling voltage is above 50V and less than 100V

3 ... Peeling voltage above 100V and below 150V

2 ... Peeling voltage above 150V, less than 200V

1 ... Peeling voltage above 200V and below 1000V

[Test Example 7] (Evaluation of Adhesiveness of Substrate)

The peeling sheet was peeled from the protective sheet manufactured in Examples and Comparative Examples, and the adhesive layer was cut into a cross (30 mm × 30 mm) cut with a blade. Then, the adhesive layer at the place where the incision was cut was rubbed with a finger pad to confirm the degree of peeling of the adhesive layer, and the adhesiveness of the substrate was evaluated based on the following criteria. The results are shown in Table 2.

○ ... The adhesive layer does not fall off from the substrate, and maintains good adhesion

△ ... A part of the adhesive layer is detached from the substrate, but a certain degree of adhesion is maintained

× ... The entire adhesive layer was detached from the substrate, and the adhesiveness was insufficient.

As can be seen from Table 2, the protective sheet manufactured in the examples has excellent antistatic properties, and also has excellent base material adhesiveness of the adhesive layer.

[Industrial profitability]

The protective sheet of the present invention is suitable for use as a protective sheet in steps such as processing, assembly, and inspection of an OLED device.

Claims (10)

    A protective plate is a protective plate for protecting a device. The protective plate is provided with a base material having a plastic film and an anti-charge layer formed on at least one side of the plastic film; and an adhesive layer. The adhesive layer is laminated on the base material layer so as to be in contact with the antistatic layer, and the adhesive layer is formed of a silicone resin adhesive.         The protection sheet according to item 1 of the scope of patent application, wherein the surface roughness of the surface of the plastic film on the side of the adhesive layer has a maximum peak height (Rp) of 200 nm or less and a maximum height (Rz) of 300 nm or less The maximum cross-sectional height (Rt) is 500 nm or less.         The protective sheet according to item 1 of the scope of patent application, wherein the other side of the plastic film is also formed with an anti-charge layer.         The protective sheet according to item 1 of the patent application scope, wherein a release sheet is laminated on a surface of the adhesive layer on the side opposite to the substrate, the release sheet having: a support; and at least formed on The antistatic layer on one side of the support.         The protective sheet according to item 1 of the scope of patent application, wherein the haze value of the protective sheet excluding the peeling sheet is 5% or less.     The protective sheet according to item 1 of the scope of patent application, wherein under the environment of 23 ° C and relative humidity of 50%, when a voltage of 100V is applied to the substrate for 10 seconds, the substrate is on the side of the adhesive layer of the substrate. The surface resistivity of the surface is 1 × 10 ⁵ Ω / sq or more and 1 × 10 ⁹ Ω / sq or less. The protective sheet according to item 1 of the scope of patent application, wherein when a voltage of 100V is applied to the substrate for 10 seconds under the environment of 23 ° C and 50% relative humidity, the substrate is opposite to the adhesive layer. The surface resistivity of the side surface is 1 × 10 ⁷ Ω / sq or more and 5 × 10 ¹¹ Ω / sq or less. The protective sheet according to item 4 of the scope of patent application, wherein when the voltage of 100V is applied to the release sheet for 10 seconds under the environment of 23 ° C and 50% relative humidity, the adhesive layer of the release sheet is applied. The surface resistivity of the side surface is 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less. The protective sheet according to item 4 of the scope of the patent application, wherein when a voltage of 100V is applied to the release sheet for 10 seconds under an environment of 23 ° C and 50% relative humidity, the release sheet and the adhesive are The surface resistivity of the surface on the opposite side of the layer is 1 × 10 ⁷ Ω / sq or more and 1 × 10 ¹¹ Ω / sq or less.     The protective sheet according to any one of claims 1 to 9, wherein the device is a flexible device.