TWI681875B - Release film having excellent peelability - Google Patents

Abstract

The present invention provides a release film having excellent peeling properties. The peel force of the release film is small. Even when the release film is adhered to the adhesive agent layer, it is difficult for the peel force to become larger over time. Little silicon component transfers to the adhesive agent layer, so the adhesion force of the adhesive agent layer does not decrease. The release film having excellent peeling properties is characterized by setting a release agent layer 4 containing silicone release agent with a thickness of 0.4-2μm on a surface of the substrate film 1, and setting a release film 5 having an adhesive agent resin layer 2 containing inorganic particle and/or polymer particle as particle 3 on another surface. Particle 3, adhesive agent resin layer 2 and release agent layer 4 meet the conditions (1) and (2). (1) The volumn basis average particle size of particle 3 is twice larger than the thickness of the release agent layer 4. (2) The thickness of the adhesive agent resin layer 2 is in a range of 25-60% of the volumn basis average particle size of particle 3.

Description

Release film with excellent peelability

The invention relates to a release film used for surface protection of various adhesive products or objects with adhesive properties. More specifically, it relates to a release film with excellent peelability, which has a small peeling force. Even if the adhesive layer is attached to the adhesive layer, the peeling force is difficult to increase even with the passage of time, and the silicone component The adhesive layer has less transfer, so it does not reduce the adhesive force of the adhesive layer.

For a long time, release films (sometimes called release films) have been used for various purposes. For example, it is widely used in: release films for molding green sheets used in the manufacture of various ceramic electronic components such as multilayer ceramic capacitors and ceramic substrates; when manufacturing polarizing plates, filters, flat panel displays, etc. A release film for an optical element having an adhesive layer; a release film for an adhesive layer for bonding an optical element used for bonding a touch panel element or an optical element, etc.

The green sheets used in the manufacture of various ceramic electronic components such as multilayer ceramic capacitors and ceramic substrates are becoming thinner as the multilayer ceramic capacitors become smaller and larger. In addition, when the green sheet is peeled from the release film, the green sheet is broken when the peeling force of the release film is large, so a release film having a smaller peeling force than conventional ones is sought.

On the other hand, polarized light as an element constituting a liquid crystal display For optical elements such as plates and retardation plates, an adhesive layer for bonding the optical element and the optical element to each other or the optical element and other elements, and a release film for protecting the adhesive layer are used.

As the size of the release film used for this application is increased, the optical elements such as polarizing plates and the size of the release film become larger, and it is necessary to be able to easily peel off even if the peeling area is large. Therefore, a release film with a smaller peeling force than conventional ones is desired. In addition, as the adhesive layer for optical elements used to bond the constituent elements and optical elements of the touch panel to each other, as the tablet PC, tablet terminal, touch panel, and the like become thinner, an adhesive with weak cohesion is used. The layer allows even the thin-film adhesive layer to follow the height difference of the optical element (for example, the height difference of frame printing of a cover glass for a portable terminal, etc.). However, in the case of using an adhesive layer with weak cohesive force, if the peeling force of the release film is too large, the adhesive layer for the optical element will be deformed, and therefore a release film having a lower peeling force than conventional ones is sought.

In this way, in the release film for forming a ceramic green sheet and various release films for optical elements having an adhesive layer, a release film having a smaller peeling force than conventional ones is desired. Against the background of the above, Patent Document 1 proposes a release film using cured silicon containing a silicone resin having only one vinyl group in the molecule.

In addition, Patent Document 2 proposes a release film in which an anti-deposition layer of an oligomer is applied to one surface of a polyester film, and a release film containing a solvent-free addition reaction-curable silicone resin is provided thereon. In the type layer, the tape peeling force is 15 mN/cm or less, and the adhesion rate of silicone resin component evaluation is 90% or more.

Furthermore, in Patent Document 3, a release film is proposed, which Addition-reactive silicone resin without functional groups such as polydimethylsiloxane without the addition of light peeling components, release film subjected to heat treatment for more than 20 hours in an environment of 50~65℃, acrylic The peeling force of the adhesive is 0.15N/50mm or less, and the residual adhesion rate is more than 90%.

In Patent Documents 1 to 3, there are proposed release films that have a small peeling force and do not reduce the adhesive force of the adhesive layer to be bonded. However, in the release film described in Patent Document 1, since a cured silicone containing a silicone resin having only one vinyl group in the molecule is used, if the vinyl reaction is incomplete, a silicone having only one vinyl group The resin is transferred to the adhesive layer, so there is a concern that the adhesive force of the adhesive layer is reduced.

In addition, the release film described in Patent Document 2 is provided with an oligomer anti-deposition layer, which is different from the conventional release film. However, due to the use of solvent-free addition reaction-curing silicone resins, the peeling performance falls into the category of traditional release films.

Furthermore, the release film described in Patent Document 3 is a light-release film formed by aging an addition reaction type silicone resin to which no light-release component is added. In this case, although it is light peeling, it is possible to obtain a release film that does not reduce the adhesive force of the adhesive layer to be bonded, but it is difficult to further reduce the peeling force.

In addition, the release film described in Patent Document 4 is a release film in which a silicone resin peeling layer containing inert particles of a predetermined particle diameter in a polyester film is formed to a predetermined thickness. By adding inert particles of a given particle size to the silicone resin peeling layer, the blocking caused by thickening the silicone resin peeling layer is solved (when the release film is rolled into a roll shape, the release film (The phenomenon that the back of the surface and the peeling layer are suspected to be stuck and cannot be wound smoothly) However, due to the inert particles, the silicone resin peeling layer becomes discontinuous. The interface between inert particles and silicone resin may cause the silicone resin to fall off. In addition, since inert particles with a larger particle size than the thickness of the silicone resin peeling layer are added, when the release film is used for the surface protection of the adhesive layer, the inert particles may adhere to the side of the adhesive layer to make the adhesive The adhesive force of the agent layer is reduced.

[Prior Technical Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2008-265227

Patent Document 2: Japanese Patent Laid-Open No. 2012-136612

Patent Document 3: Japanese Patent Laid-Open No. 2006-007689

Patent Document 4: Japanese Patent Application Publication No. 2013-208897

The technical problem of the present invention is to provide a release film with excellent releasability, which has a small peeling force, and it is difficult for the peeling force to increase even if time passes while being attached to the adhesive layer, and the silicone resin component is applied to the adhesive layer There is little transfer, so it will not reduce the adhesion of the adhesive layer.

In order to solve the above problems, careful research was carried out, and the results were clear. In order not to reduce the adhesion of the adhesive layer, it is necessary to make the release film using a silicone release agent (sometimes called a release agent) into silicon The release film with less oxygen resin transfer to the adhesive layer. In addition, even in the case of using a silicone-based release agent with a small amount of silicone resin transferred to the adhesive layer, a study was conducted to reduce the peeling force, and the results were clear. By making the thickness of the release agent layer Specific thickness It can reduce the peeling force. However, it is clear that when the thickness of the release agent layer is increased, the release film is wound into a roll shape, and the release agent layer is stuck when it is attached to the back surface of the release film, and the release film cannot be Roll back smoothly into a roll shape. In the manufacturing process of the base film used for the release film, the base film contains lubricant particles to form a film so that the base film does not block even when it is wound into a roll shape. Therefore, on the back surface of the release film, although the surface of the base film has an uneven structure, by thickening the thickness of the release agent layer, the uneven structure in which the release agent layer fills the surface of the base film is considered to be sticky Even the reason.

In addition, the method of taking into consideration both peelability and blocking resistance has been carefully studied, and the present invention can be completed. In the present invention, even in the case where a release agent with little silicone resin component transfer to the adhesive layer is used, in order to reduce the peeling force, the thickness of the release agent layer is 0.4 μm or more. In addition, the technical idea of the present invention is that, in order to prevent the adhesion of the release agent layer and the back surface of the release film, a thickness corresponding to the thickness of the release agent layer is formed on the surface of the base film opposite to the release agent layer The roughness of the surface roughness shape, so as to balance peeling and blocking resistance.

In order to solve the above technical problems, the present invention provides a release film, characterized in that a release agent layer containing a silicone resin release agent with a thickness of 0.4 to 2 μm is provided on one surface of the base film. The other side is provided with a binder resin layer containing inorganic particles and/or polymer particles as particles, the particles, the binder resin layer and the release agent layer satisfy (1) the volume basis of the particles The average particle diameter is more than twice the thickness of the release agent layer, and (2) the thickness of the binder resin layer is in the range of 25 to 60% of the volume-based average particle diameter of the fine particles.

The inorganic fine particles are preferably selected from silicon dioxide, calcium carbonate, One or more types of inorganic particles composed of calcium phosphate, barium sulfate, kaolin, glass powder, and talc. In addition, the polymer fine particles are preferably selected from the group consisting of silicone resin, acrylic resin, polyamide resin, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, epoxy resin More than one type of polymer resin particle group composed of similar resins.

In addition, the base film is preferably a polyester resin film.

In addition, the present invention provides a laminated film having a laminate or a single adhesive layer in which an adhesive layer is laminated on at least one surface of a resin film, and the release film, which is formed by passing the release film The release agent layer is formed on the surface of the adhesive layer.

According to the present invention, it is possible to provide a release film having excellent releasability for forming a ceramic green sheet release film and various optical elements having an adhesive layer. In addition, the present invention can provide a release film with excellent releasability. The release force of the release film is small. Even if the adhesive layer is adhered to the adhesive layer, the peeling force is difficult to increase and the silicone resin component tends to increase. The transfer of the adhesive layer is small, so the adhesive force of the adhesive layer is not reduced.

In addition, the release film of the present invention does not reduce the adhesive force of the adhesive layer to be bonded, and can be smoothly rolled back without blocking even when wound into a roll shape, thus taking into consideration both excellent peelability and resistance Adhesion, the use value in the industry is large, so its industrial value is great.

1‧‧‧ Base film

2‧‧‧Binder resin layer

3‧‧‧Inorganic particles or polymer particles

4‧‧‧ Release agent layer

5‧‧‧ Release film

6‧‧‧adhesive layer

7‧‧‧Optical film

8‧‧‧Laminate of optical film and adhesive layer

9‧‧‧Optical adhesive sheet

10‧‧‧Viscous optical film

1 is a cross-sectional view schematically showing an example of the release film of the present invention; 2 is a cross-sectional view schematically showing an example of the first embodiment of the laminated film of the present invention; FIG. 3 is a cross-sectional view schematically showing an example of the second embodiment of the laminated film of the present invention.

Hereinafter, suitable embodiments of the present invention will be described.

1 is a cross-sectional view schematically showing an example of a release film of the present invention, an adhesive resin layer 2 is formed on one surface of a base film 1, and silicone resins are formed on an opposite surface of the base film 1 Parting agent layer 4.

The adhesive resin layer 2 contains inorganic particles and/or polymer particles 3 as anti-blocking particles.

In the release film 5 of the present invention, the resin film used as the base film 1 may be selected according to the application, and examples thereof include polyester resin films, polyamide resin films, polyimide resin films, and polyolefin resins. Film, polyvinyl chloride resin film, polystyrene resin film, acrylic resin film, acetate resin film, polyphenylene sulfide resin film, etc.

Among them, the polyester resin film is suitable in terms of characteristics such as optical characteristics, heat resistance characteristics, price, appearance, and the like. Examples of polyester resins include polyethylene terephthalate, polyethylene naphthalate, copolymers of polyethylene isophthalate and polyethylene terephthalate, Polybutylene terephthalate, etc. Among them, polyethylene terephthalate (PET) is particularly preferred from the viewpoint of cost or optical characteristics. In addition, in view of optical characteristics, it is preferably polyethylene terephthalate for uniaxially stretched products or biaxially stretched products.

In addition, if necessary, a plasma may be applied to the surface of the base film 1 Surface modification of discharge or corona discharge, easy adhesion treatment such as application of tackifier.

The thickness of the base film 1 is not particularly limited, and the thickness of the base film 1 is preferably about 10 to 200 μm in consideration of ease of handling as the release film 5 or winding the release film 5 into a roll shape.

In the present invention, even if the thickness of the release agent layer containing the silicone-based release agent is increased, a surface conforming to the thickness of the release agent layer is formed on the surface of the base film 1 opposite to the release agent layer The roughness of the uneven structure prevents the release agent layer from sticking when it is attached to the back of the release film. The uneven structure is formed on the surface of the base film 1 by coating the binder resin layer 2 containing inorganic fine particles and/or polymer fine particles 3 as anti-blocking fine particles.

Examples of the inorganic fine particles and/or polymer fine particles 3 serving as anti-blocking fine particles include inorganic fine particles as inorganic compound fine particles and polymer fine particles as polymer resin fine particles. Either inorganic fine particles or polymer fine particles can be used, or both can be used together. The inorganic fine particles are preferably one or more types selected from the group of inorganic particles composed of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass frit, and talc. In addition, the polymer fine particles are preferably selected from silicone resins, acrylic resins, polyamide resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene resins, epoxy resins One or more of the polymer resin particles formed.

The shape of the fine particles 3 is not particularly limited, and may be spherical, rod-shaped, scaly, hemispherical, lenticular, mushroom-shaped, irregular, etc. Since the spherical or nearly spherical shape tends to exhibit anti-blocking properties, More suitable.

As the volume-based average particle diameter, the particle diameter of the fine particles 3 is preferably at least twice the thickness of the release agent layer 4. If the volume-based average particle size of the particles 3 is smaller than the release agent layer If the thickness of 4 is doubled, the anti-blocking property may be reduced. When the volume-based average particle diameter of the fine particles 3 is at least twice the thickness of the release agent layer 4, anti-blocking performance can be obtained. The upper limit of the volume-based average particle diameter of the fine particles 3 is not particularly a problem, but when the volume-based average particle diameter of the fine particles 3 is increased, it is necessary to increase the thickness of the adhesive resin layer 2 to increase the cost. Therefore, the volume-based average particle diameter of the fine particles 3 is preferably controlled to about 10 times the thickness of the release agent layer 4. In addition, according to the volume-based average particle size, the large particles have a large effect and the small particles have little effect even if they are mixed in. Therefore, as long as at least a part of the particles have a particle diameter more than twice the thickness of the release agent layer 4, Obtain anti-blocking properties.

The resin used for the adhesive resin layer 2 is not particularly limited as long as the fine particles 3 are dispersed and attached to the base film 1. For example, polyester resin, acrylic resin, polyurethane resin, alkyd resin, silicone resin, cellulose resin, polyvinyl alcohol, silane coating agent, silicate coating agent, etc. .

The resin used for the adhesive resin layer 2 may be water-based, non-aqueous (solvent-based), or solvent-free. The thickness of the adhesive resin layer 2 is preferably in the range of 25 to 60% of the volume-based average particle diameter of the fine particles 3. If the thickness of the adhesive resin layer 2 is less than 25% of the volume-based average particle diameter of the fine particles 3, the anchoring force of the fine particles 3 decreases, and the fine particles 3 easily fall off. In addition, if the thickness of the adhesive resin layer 2 exceeds 60% of the volume-based average particle diameter of the fine particles, problems such as reduced anti-blocking performance and high cost are generated, which is not preferable.

The fine particles 3 are mixed in the resin forming the adhesive resin layer 2 and coated on the base film 1. A part (upper part) of the fine particles 3 protrudes more than the thickness of the adhesive resin layer 2 (the average thickness of the part without the fine particles 3). On particle 3 The resin of the adhesive resin layer 2 may be thinly attached to the surface of the portion, or may not be attached.

In terms of preventing the adhesion of the release film, it is important that the particles 3, the adhesive resin layer 2 and the release agent layer 4 satisfy the following two conditions: (1) The volume-based average particle diameter of the particles 3 is the release agent layer 4 or more than twice the thickness; (2) The thickness of the adhesive resin layer 2 is in the range of 25 to 60% of the volume-based average particle diameter of the fine particles 3.

The method of mixing and dispersing the fine particles 3 in the binder resin may be performed using a known method according to the types of binder resin and fine particles. If it is a system in which fine particles are easily dispersed in the binder resin, it may be stirred and mixed using a hand tool such as a spatula. Even if it is a combination of particles that are difficult to disperse in the binder resin, or a system that is easy to disperse, when the binder resin and particles are large, a disperser such as a homogenizer or homomixer can be used Perform dispersion mixing. In addition to fine particles and binder resins, surfactants, colorants, antistatic agents, paraffin wax and other lubricants, silicone resins or fluorine antifouling agents, leveling agents, curing agents and preservatives can also be added as needed Wait.

The formation of the binder resin layer 2 containing fine particles 3 may be provided by applying the binder resin containing fine particles 3 to the base film 1. The coating method is not particularly limited, as long as it is selected from known coating methods according to the viscosity of the binder resin containing the fine particles 3 and the coating amount. As an example, a meyer bar method, a concave plate method, a reverse roll method, an air knife method, a multi-stage roll method, etc. are mentioned.

The curing of the adhesive resin layer 2 containing fine particles 3 or Solidification may be performed according to the type of binder resin. For example, the binder resin can be cured by heating and drying to remove solvents, water, etc., or by ultraviolet irradiation or electron beam irradiation.

Examples of the release agent used for the release agent layer 4 include silicone-based release agents. Examples of silicone resin-based release agents include well-known silicone resin-based release agents such as addition reaction type, condensation reaction type, cation polymerization type, and radical polymerization type. Examples of products commercially available as addition reaction type silicone resin release agents include KS-776A, KS-776L, KS-847, KS-847T, KS-779H, KS-837, and KS- 778, KS-830, KS-774, KS-3565, X-62-2829, KS-3650, KNS-3051, KNS-320A, KNS-316, KNS-3002, X-62-1387 (Xinyue Chemical Industry ( Stock), SRX-211, SRX-345, SRX-357, SD7333, SD7220, SD7223, LTC-300B, LTC-350G, LTC-310, LTC-750A, SP-7025, SP-7248S, SP-7015 , SP-7259, LTC-1006L, LTC-1056L (manufactured by Dow Corning Toray), TPR-6722, TPR-66721, TPR-6702, TPR-6700, TPR-6600, SL6625 (manufactured by Momentive Performance Materials) Wait. Examples of products commercially available as condensation reaction types include SRX-290, SYLOFF-23 (manufactured by Dow Corning Toray Co., Ltd.), and YSR-3022 (manufactured by Momentive Performance Materials). Examples of products that are commercially available as cationic polymerization types include TPR-6501, TPR-6502, TPR-6500, UV9300, VU9315, UV9430 (made by Momentive Performance Materials), X62-7622, X-62-7660 , X-62-7655 (Shinyue Chemical Industry Co., Ltd.), etc. Examples of products that are commercially available as radical polymerization types include, for example, KF-2005, X62-7205 (Shinyue Chemical Industry Co., Ltd.), etc. Examples of the release agent with little transfer of the silicone resin component to the adhesive layer include silicone resins that do not contain a light-release additive component (do not contain organic functional groups participating in the addition reaction, for example, polydimethylsiloxane Etc.) silicone release agent.

The silicone resin-based release agent used in the release film of the present invention may be used alone or in combination of multiple varieties. In addition, components other than the silicone resin-based release agent such as a silane coupling agent, an antistatic agent, and a wettability improver may be added as long as they are determined in consideration of peelability, coatability, curability, and the like. The application of the release agent can be performed by a well-known method and is not particularly limited, and examples thereof include a wire bar method, a gravure method, a reverse roll method, an air knife method, and a multi-stage roll method. The curing method of the silicone resin-based release agent may include heating curing, ultraviolet curing, electron beam curing, simultaneous use of heating and ultraviolet irradiation, and an appropriate method may be selected according to the type of silicone resin-based release agent. The thickness of the release agent layer 4 containing a silicone resin-based release agent is, for example, 0.4 to 2 μm. If the thickness of the release agent layer 4 is less than 0.4 μm, the peeling force tends to increase. In addition, the upper limit of the thickness of the release agent layer 4 is not particularly a problem, and when the thickness of the release agent layer 4 is increased, the volume-based average particle diameter of the fine particles 3 needs to be increased, and the binder needs to be made The thickness of the resin layer 2 is increased, and the cost is increased. Therefore, the thickness of the release agent layer 4 is preferably controlled to about 2 μm.

When the release film 5 of the present invention is used for a release sheet for forming a green sheet used for manufacturing various ceramic electronic components, the green sheet is formed by dispersing the ceramic particles in an organic solvent The slurry is formed by coating and drying. In such a release film 5 for protecting a green sheet, the release agent layer 4 requires solvent resistance. Since the release agent layer 4 of the present invention does not contain fine particles 3, it is a silicone resin type release agent that is not discontinuous and has good solvent resistance. The agent layer 4 can be suitably used for protecting green sheets. In addition, it is not limited to a green sheet, and can be suitably used for the purpose of protecting surfaces of coating films in which various powders are dispersed, such as conductive pastes and insulating pastes, and coating films containing solvents.

2 is a cross-sectional view schematically showing an example of the first embodiment of the laminated film of the present invention. The adhesive optical film 10 of FIG. 2 uses the release film 5 of the present invention for protecting the adhesive layer 6 laminated on the optical film 7. On the release film 5 of the present invention of FIG. 1, an optical film 7 is bonded via an adhesive layer 6. The manufacturing method of such an adhesive optical film 10 may be that a solvent-based adhesive is coated on the release film 5, and after drying, the optical film 7 is bonded. In such a release film 5 for protecting the adhesive layer 6, the release agent layer 4 requires solvent resistance. Since the release agent layer 4 of the present invention does not contain fine particles 3, it is a release agent layer 4 in which silicone release agents are not discontinuous and have good solvent resistance, and can be suitably used to protect the adhesive layer 6 In use. The laminate containing the adhesive layer 6 may contain one or more resin films and one or more adhesive layers. For example, the adhesive layer 6 may be provided on both sides of the optical film 7, and the release film 5 may be stuck on each adhesive layer 6. As another manufacturing method, the release film 5 may be bonded to the laminate 8 provided with the adhesive layer 6 on one surface of the optical film 7. Alternatively, after applying the solventless adhesive, the adhesive layer 6 can be cured between the release film 5 and the optical film 7 by transmitting light or heat.

3 is a cross-sectional view schematically showing an example of the second embodiment of the laminated film of the present invention. The optical adhesive sheet 9 of FIG. 3 is bonded to the adhesive layer 6 for bonding touch panel elements and optical elements, and the release film 5 of the present invention is bonded to protect the adhesive layer 6. The optical adhesive sheet 9 is in a form where two release films 5 sandwich the adhesive layer 6. In the manufacturing method of this optical adhesive sheet 9, in general, After coating and drying the solvent-based adhesive on one piece of release film 5, it is bonded to the other piece of release film 5. In such a release film 5 for protecting the adhesive layer 6, the release agent layer 4 requires solvent resistance. Since the release agent layer 4 of the present invention does not contain fine particles 3, it is a release agent layer 4 in which silicone release agents are not discontinuous and have good solvent resistance, and can be suitably used to protect the adhesive layer 6 In use.

The adhesive used for the adhesive layer 6 may be aqueous, non-aqueous (solvent) or solvent-free. As the adhesive, acrylic adhesives, silicone adhesives, rubber adhesives, polyurethane adhesives, etc. may be used. Acrylic adhesives are preferred because they are excellent in transparency and weather resistance.

The resin film used for the laminated film is not limited to the optical film 7 as long as it is an opaque resin film. Examples of the optical film include a polarizing film, a retardation film, an anti-reflection film, an anti-glare film, an ultraviolet absorption film, an infrared absorption film, an optical compensation film, a brightness enhancement film, and a high transparency film.

Examples

Hereinafter, the present invention will be specifically described with examples.

(Release film of Example 1)

To the beaker, 7.5 parts by weight of ethyl cellulose (manufactured by DOW Chemical Co., Ltd., trade name: ETHOCEL (registered trademark) 100FP), 0.0375 parts by weight of silicone resin with an average particle diameter (volume-based average particle diameter) of 2 μm were polymerized Fine particles (Momentive Performance Materials, trade name: Tospearl (registered trademark) 120), 92.5 parts by weight of a 50/50 mixed solvent of toluene/ethyl acetate were mixed, and stirred until ethyl cellulose was dissolved to prepare a paint. Next, on the corona-untreated surface of the single-sided corona-treated polyester film with a thickness of 50 μm, it was applied by a wire-bar method so that the thickness of the dried binder resin was 1.0 μm, and then used A hot air circulation dryer at 120°C was heated for 1 minute to obtain a polyester film having a surface uneven shape on one surface. Then, on the opposite surface (corona-treated surface) of the surface of the obtained polyester film provided with the concave-convex shape, an addition reaction type silicone resin release agent (Dow) was applied with respect to 30 parts by weight by a wire bar method Corning Toray Corporation, trade name: LTC-1056L) after mixing 1 part by weight of platinum catalyst (Dow Corning Toray Corporation, trade name: SRX212 CATALYST), 70 parts by weight of a 50/50 mixed solvent of toluene/ethyl acetate The paint was dried to a thickness of 1.0 μm, and heated using a hot air circulation dryer with a set temperature of 120° C. for 1 minute to obtain a release film of Example 1.

(Confirmation of adhesion)

In Example 1, the thicknesses of the binder resin layer (ethyl cellulose) and the release agent layer and the types of silicone resin polymer fine particles were changed to obtain release films of Production Examples 1 to 12. In addition, the said Example 1 is the manufacturing example 5 of Table 1.

Regarding the obtained release films of Production Examples 1 to 12, a confirmation experiment was conducted to determine whether the release agent layer and the adhesive resin layer were stuck or not, and whether particles were falling off.

(Check for adhesion)

Three samples with overlapping release films were made and sandwiched between two stainless steel plates (SUS304). On this sample, in a state where a load of 20 g/cm ² {0.196 N/cm ² } was applied, it was left in an environment of 23° C. and 50% RH for 24 hours. Then, take out three overlapping release films and confirm the adhesion state by peeling off the release films one by one by hand. Non-adhesive, the release film is easily peeled off is good adhesion (○), there is some resistance when the release film is peeled off is slightly poor adhesion (△), there is significant resistance when the release film is peeled off is adhesion Poor connectivity (×).

(Confirm whether particles fall off)

The non-woven fabric (bemcot (registered trademark) M-1 manufactured by Asahi Kasei Fiber Co., Ltd.) was used to wipe the back and forth of the particulate resin-containing adhesive resin coated surface of the release film in a state where a load was applied with a 200 g weight. Then, observe the wiped part of the sample with a laser microscope. The number of particles remaining and falling off was measured in 10 places. If the falling off of the particles was less than 30%, it was good (○), and when the falling off of the particles was more than 30%, it was bad (×).

(Confirm the test results)

The results of the confirmation test are shown in Table 1.

From the results of the confirmation test shown in Table 1, it can be seen that as the condition that the release agent layer and the adhesive resin layer do not block, as the thickness of the release agent layer becomes thicker, the surface roughness of the adhesive resin layer is required (Bump) The larger. In addition, from the results of the confirmation test shown in Table 1, as the conditions under which the release agent layer and the adhesive resin layer did not block, the following fine particles (inorganic fine particles or polymer fine particles) were obtained The relationship between the volume-based average particle diameter and the thickness of the release agent layer and the thickness of the binder resin layer relative to the average particle diameter of the particles (inorganic particles or polymer particles): (i) the average particle diameter of the particles It is more than twice the thickness of the release agent layer; (ii) The thickness of the binder resin layer is less than 75% relative to the average particle diameter of the particles.

On the other hand, as a condition for preventing the fine particles from falling off from the binder resin layer containing fine particles, it is necessary to increase the thickness of the binder resin layer with respect to the average particle diameter of the fine particles. From the results of the confirmation test shown in Table 1, the thickness of the binder resin layer that does not cause particles to fall off from the binder resin layer containing particles is derived as follows: (iii) The thickness of the binder resin layer is 25% or more of the average particle diameter of the fine particles.

In addition, from the results of the confirmation test shown in Table 1, it is known from the comparison between Production Example 6 and Production Example 7 that, as for condition (ii), as long as the thickness of the binder resin layer relative to the volume-based average particle diameter of the fine particles is Below 60%, there is no adhesion between the release agent layer and the adhesive resin layer.

That is, according to the results of the confirmation test shown in Table 1, as the conditions under which the release agent layer and the adhesive resin layer do not block, and the conditions under which the fine particles do not fall off from the adhesive resin layer containing fine particles, the following conditions are obtained: 1) The average particle diameter of the particles is more than twice the thickness of the release agent layer; (2) The thickness of the binder resin layer is in the range of 25-60% of the average particle diameter of the particles.

(Example 2)

Except for setting the thickness of the release agent layer to 0.4 μm The release film of Example 2 was produced in the same manner.

(Example 3)

The release film of Example 3 was produced in the same manner as Example 1 except that the thickness of the release agent layer was set to 0.5 μm.

(Example 4)

7.5 parts by weight of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: POVAL 203) and 92.5 parts by weight of ion-exchanged water were weighed. Add ion-exchanged water to the beaker. After heating to about 80°C, add polyvinyl alcohol while stirring, and continue stirring until the polyvinyl alcohol is completely dissolved. After cooling to normal temperature, 0.0375 parts by weight of amorphous silica (average particle size 2.7 μm based on volume basis) (made by Fuji silysia, trade name: sylysia (registered trademark) 310P) is added, and the mixture is stirred and mixed to the dioxide Silicon is evenly dispersed to make binder resin coatings containing particles.

Next, apply the prepared adhesive resin coating on the corona-treated surface of the corona-treated polyester film with a thickness of 50 μm on both sides through a wire rod method, so that the thickness of the dried adhesive resin is 1 μm, and the set temperature is used A 120 degreeC hot-air circulation dryer was heated for 3 minutes, and the polyester film which provided the surface uneven shape on one surface was obtained. Then, on the opposite surface (corona-treated surface) of the uneven shape of the obtained polyester film, a mixed addition reaction type silicone release agent (18 parts by weight made by Dow Corning Toray Co., Ltd. trade name) was applied by wire bar method. : LTC-1056L, 40 parts by weight of Shin-Etsu Chemical Co., Ltd. trade name: KS-847T), 1 part by weight of platinum catalyst (Dow Corning Toray Corporation, trade name: SRX212 CATALYST), 42 parts by weight of toluene/ethyl acetate The paint after the 50/50 solvent mixture was heated to a thickness of 1.0 μm after drying, and heated for 1 minute using a hot-air circulation dryer with a set temperature of 120° C. to obtain a release film of Example 4.

(Comparative example 1)

A release film of Comparative Example 1 was produced in the same manner as in Example 1, except that the thickness of the release agent layer was 0.2 μm.

(Comparative example 2)

A release film of Comparative Example 2 was produced in the same manner as in Example 1, except that the thickness of the binder resin layer (ethyl cellulose) after drying was set to 1.5 μm. In addition, Comparative Example 2 is Production Example 7 of Table 1.

(Comparative example 3)

On a corona-treated surface of a single-sided corona-treated polyester film with a thickness of 50 μm, an addition reaction type silicone resin release agent (Dow Corning Toray Co., Ltd.) with respect to 5 parts by weight of a light peeling type was applied by a wire bar method. Co., Ltd., trade name: SRX-357) A mixed paint of 0.05 parts by weight of a platinum catalyst (manufactured by Dow Corning Toray, trade name: SRX212 CATALYST) and 95 parts by weight of a 50/50 mixed solvent of toluene/ethyl acetate, The thickness after drying was 0.2 μm, and it was heated for 1 minute using a hot-air circulation dryer with a set temperature of 120° C. to obtain a release film of Comparative Example 3.

(Comparative example 4)

To 30 parts by weight of an addition reaction type silicone release agent (manufactured by Dow Corning Toray, trade name: LTC-1056L), 1 part by weight of a platinum catalyst (manufactured by Dow Corning Toray company, trade name: SRX212), 70 To the mixed paint, add 0.0375 parts by weight of silicone resin polymer fine particles (based on Momentive Performance Materials Co., Ltd., trade name: 0.0375 parts by weight of a volume-based average particle diameter of 2 μm) to the mixed paint. TOSPEARL (registered trademark) 120), stir and mix to make a silicone resin release agent coating containing fine particles. In thickness A single-sided corona-treated polyester film with a thickness of 50 μm is coated with the prepared coating through a wire-bar method so that the thickness after drying is 1.0 μm, and a hot-air circulation dryer with a set temperature of 120°C is used After heating for 1 minute, the release film of Comparative Example 4 was obtained.

For the release films obtained in Examples 1 to 4 and Comparative Examples 1 to 4, various measurements and confirmation tests were performed. The method of confirming the presence or absence of adhesion is as described above. The other test methods are as follows.

(Measurement of peel force)

A polyester adhesive tape (manufactured by Nitto Denko Corporation, trade name: polyester tape No. 31B) is attached to the surface of the release agent layer of the release film, and a load of 20 g/cm ² {0.196N/cm ² } After aging at 70°C for 20 hours, a desktop precision universal testing machine (Shimadzu Corporation, Autograph (registered trademark)) was used to measure the peel strength at a peeling speed of 300 mm/minute and a peeling angle of 180° as peeling. Force (mN/50mm).

(Determination of residual adhesion rate)

The adhesive tape peeled from the release film after the above-mentioned (measurement of peeling force) test is pressed against the adherend (stainless steel plate) with a roller, and placed under an environment of 23°C and 55% RH for 1 hour, and then used A bench-top precision universal testing machine (manufactured by Shimadzu Corporation, Autograph (registered trademark)) measured the peeling force when peeling from the adherend at a peeling speed of 300 mm/min and a peeling angle of 180° as the residual adhesive strength.

Except for this, the peeling force when the unused adhesive tape was pressure-bonded to the adherend of the same material and peeled off was measured as the standard adhesive force.

Calculate the residual adhesion rate by the formula (residual adhesion)/(reference adhesion)×100(%).

(Confirmation of the adhesion of the release agent layer)

After vigorously wiping the surface of the release agent layer of the release film after the above-mentioned (measurement of peeling force) test with a finger pad 3 times, the wiped portion was visually observed. Visually confirm whether the release agent layer has fallen off from the base film, and the evaluation of almost no release agent layer peeling is (○), the release agent layer is slightly peeled off (△), and the release agent layer is significantly peeled off. Is (×).

(Confirmation of the solvent resistance of the release agent layer)

Using a non-woven fabric impregnated with ethyl acetate (bemcot (registered trademark) M-1 manufactured by Asahi Kasei Fiber Co., Ltd.), the release agent layer of the release film was wiped back and forth once with a load of 200 g being applied. Then, by visually observing the release agent layer of the release film, the solvent resistance of the release agent layer of the release film was confirmed. The surface of the release agent layer was visually confirmed, and the change in appearance was evaluated as (○), and the release agent was evaluated as (×).

(Results of measurement and confirmation test)

Table 2 shows the results of various measurements and confirmation tests of the release films obtained in Examples 1 to 4 and Comparative Examples 1 to 4.

(to sum up)

The peeling force of the release film of Examples 1 to 4 is very small, and the residual adhesion rate shows Very high value. In addition, the release agent layer and the adhesive resin layer of the release films of Examples 1 to 4 did not block, and the adhesion and solvent resistance of the silicone resin-based release agent were also good. On the other hand, the release film of Comparative Example 1 in which the thickness of the release agent layer is thin has a peeling weight (large peeling force). In addition, the release film of Comparative Example 2 in which the unevenness of the adhesive resin layer containing fine particles on the back side of the release agent (the ratio of the thickness of the adhesive resin layer to the average particle diameter of the fine particles is large) was stuck and peeled off The force also becomes larger. The release film of Comparative Example 3 in which a light-release silicone resin that is generally used is applied at a general coating amount has heavier peeling than Examples 1 to 4, and results in a significantly worse residual adhesion rate. The release film and the residual adhesion ratio of the release film of Comparative Example 4 containing fine particles in the silicone-based release agent also had good results, but the adhesion and solvent resistance of the release agent layer were poor .

1‧‧‧ Base film

2‧‧‧Binder resin layer

3‧‧‧Inorganic particles or polymer particles

4‧‧‧ Release agent layer

5‧‧‧ Release film

Claims (4)

A release film with excellent peelability, characterized in that a release agent layer having a thickness of 0.4-2 μm and containing a silicone resin release agent is provided on one surface of the base film, and the other surface is provided There is a binder resin layer containing inorganic fine particles and/or polymer fine particles as fine particles, the release film bonded to the surface of the binder layer through the release agent layer, the fine particles, the binder resin The layer and the release agent layer satisfy the following conditions (1) and (2): (1) The volume-based average particle diameter of the fine particles is more than twice the thickness of the release agent layer; (2) The thickness of the binder resin layer is in the range of 25 to 60% of the volume-based average particle diameter of the fine particles. The release film with excellent peelability as described in item 1 of the patent application scope, wherein the inorganic particles are selected from the group consisting of silicon dioxide, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, and talc One or more of the inorganic particle groups, the polymer particles are selected from silicone resins, acrylic resins, polyamide resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene One or more types of polymer resin particles composed of ethylene resin and epoxy resin. The release film with excellent peelability as described in item 1 or 2 of the patent application, wherein the base film is a polyester resin film. A laminated film having a laminate or a single adhesive layer in which an adhesive layer is laminated on at least one surface of a resin film, and having excellent peeling according to any one of items 1 to 3 of the patent application range Release film, the release film with excellent peelability is attached to the adhesive layer through the release agent layer Surface.

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