TWI725831B - 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 5 having excellent peeling properties is characterized by setting a first release agent layer 2 which does not contain microparticle and a second release agent layer 4 which have inorganic macroparticles and/or polymer macroparticles as macroparticles 3. A total thickness of the first release agent layer 2 and the second release agent layer 4 is between 0.4 to 2μm, and an average protruding height extending from a surface of the second release agent layer 4 to a peak of the macroparticles 3 is greater than the total thickness. Moreover, the second release agent layer 4 contains a silicon-type release agent.

Description

Release film with excellent peelability

The invention relates to a release film, which is used for the protection of an adhesive layer in an optical component with various adhesive products and an adhesive layer. In more detail, it relates to a release film with excellent peelability. The peeling force is small, and the peeling force is not easy to increase even after a long time in the state of being stuck on the adhesive layer, and due to the silicon transferred to the adhesive layer There are few ketones and does not reduce the adhesive force of the adhesive layer to be attached.

In the past, release films (also called release films) were used in various applications. Among them, it is widely used in the production of laminated ceramic capacitors, ceramic substrates and other various ceramic electronic components used in the molding of the release film for the original plate, and has an adhesive layer used in the production of polarizers, optical films, flat panel displays, etc. The release film for optical components, the release film used for bonding between touch panel components or optical components, and the release film for the adhesive layer for bonding optical components.

The original plates used in the manufacture of various ceramic electronic components such as multilayer ceramic capacitors and ceramic substrates have been thinned as multilayer ceramic capacitors have become smaller and larger in capacity. When the original sheet is peeled from the release film, if the peeling force of the release film is large, the original sheet is damaged, and therefore, a release film having a lower peel force than the conventional one is required.

On the other hand, in optical components such as polarizers and retardation plates that constitute liquid crystal displays, a release film for protecting the adhesive layer formed on the optical component is used, and the adhesive layer is used for the optical component Fitting between or with other components. As the size of the release film used in this application increases, the size of optical components such as polarizers and the release film becomes larger, and it is required that it can be easily peeled even if the peeling area is large. Therefore, a release film with a lower peel force than before is required. In addition, for the adhesive layer for optical parts used to bond the constituent parts of the touch panel or between the optical parts, with the thinning of tablets, tablet terminals, touch panels, etc., an adhesive layer with weak cohesive force is used , So that the film adhesive layer can also follow the level difference of the optical component (for example, the level difference of the frame printing of the cover glass of the portable terminal, etc.). However, when an adhesive layer with weak cohesive force is used, if the peeling force of the release film is too large, the adhesive layer for optical parts will be deformed. Therefore, a release film with a lower peeling force than in the past is required.

In this way, release films for molding ceramic original plates and release films for optical components having various adhesive layers require a release film with a lower peel force than in the past. In the context of the above, Patent Document 1 proposes a release film that uses a cured silicone containing silicone having only one vinyl group in its molecule. In addition, Patent Document 2 proposes a release film in which an oligomer precipitation prevention layer is applied on one surface of a polyester film, and there is an addition reaction curable silicone type release film containing a solvent-free type on this layer. Layer, the tape peeling force is 15mN/cm or less, and the silicone-based component transferability evaluation adhesion rate is 90% or more. In addition, Patent Document 3 proposes a release film that uses an addition reaction type silicone that does not contain a light release component, such as polydimethylsiloxane without functional groups, and is carried out in an environment of 50 to 65°C. After heat treatment for more than 20 hours, the peeling force of acrylic adhesive is 0.15N/50mm or less, and the residual adhesion rate is more than 90%.

All of Patent Documents 1 to 3 propose a release film that has a small peeling force and does 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 silicone with only one vinyl group in the molecule is used, if the vinyl group is not completely reacted, only one vinyl group is used in the molecule. The base silicone will transfer to the adhesive layer, and there is a concern that the adhesive force of the adhesive layer will decrease. In addition, the release film described in Patent Document 2 is different from the conventional release film in that an oligomer precipitation prevention layer is provided. However, since a solvent-free addition reaction curable silicone is used, the peelability is within the scope of the conventional release film. Furthermore, in the release film described in Patent Document 3, the addition reaction type silicone to which a light-peeling component is not added is cured to be light-peeled. In this case, although it is lightly peeled, it is possible to obtain a release film that does not reduce the adhesive force of the bonded adhesive layer, but it is difficult to further reduce the peeling force.

In addition, the release film described in Patent Document 4 is a silicone release layer in which inert particles having a predetermined particle diameter are applied to a polyester film in a predetermined thickness. By adding inert particles of specified particle size to the silicone release layer to solve the blocking caused when the silicone release layer is thickened (blocking, when the release film is rolled up in a roll, the back of the release film and the release layer It seems to be stuck together and cannot be curled smoothly). However, since the silicone peeling layer becomes discontinuous due to the inert particles, if it comes into contact with the solvent, the solvent will penetrate into the interface between the inert particles and the silicone, which may cause the silicone to fall off. In addition, in order to add inert particles with a larger particle size than the thickness of the silicone release layer, when the release film is used to protect the surface of the adhesive layer, the inert particles adhere to the adhesive layer side, which may cause adhesion. The adhesive force of the agent layer is reduced. Prior art literature Patent literature

Patent Document 1: Japanese Patent Application Publication No. 2008-265227 Patent Document 2: JP 2012-136612 A Patent Document 3: Japanese Patent Laid-Open No. 2006-007689 Patent Document 4: JP 2013-208897 A

Technical problem to be solved by the present invention

The technical problem of the present invention is to provide a release film with excellent peelability, which has a small peeling force, and the peeling force is not easy to increase even after a long time in the state of being attached to the adhesive layer, and due to the transfer to the adhesive layer The silicone component is small, and the adhesive force of the bonded adhesive layer is not reduced. Technical means to solve technical problems

From the results of in-depth discussions to solve the above problems, it can be seen that in order not to reduce the adhesive force of the adhesive layer, it is necessary to transfer the release film using a silicone-based release agent (also called a release agent) to the adhesive The agent layer has less silicone. In addition, even in the case of using a silicone-based release agent with less silicone transferred to the adhesive layer, studies have been conducted to reduce the peeling force. As a result, it has been found that by making the thickness of the release agent layer more than a certain thickness, Can reduce the peeling force. However, it has also been found that when the thickness of the release agent layer is increased, the release film is curled in a roll, and the release agent layer and the back of the release film cause adhesion, which cannot make the release film smoothly Curl into a roll. In the production process of the base film used for the release film, in order to prevent blocking when the base film is curled in a roll shape, the base film contains slip agent particles and forms a film. Therefore, it is believed that the cause of the blocking is that on the back of the release film, the surface of the base film has an uneven structure, but by increasing the thickness of the release agent layer, the uneven structure on the surface of the base film is covered by the release agent layer. Landfill.

In addition, a method for achieving both peelability and blocking resistance has been carefully studied, and the present invention has been completed. In the present invention, even when a release agent with a small amount of silicone components transferred to the adhesive layer is used, in order to reduce the peeling force, the thickness of the release agent layer is set to 0.4 μm or more. In addition, in order to prevent the adhesion between the release agent layer and the back surface of the release film, the present invention forms a concave-convex shape with a moderate surface roughness on the release agent layer to achieve both peelability and anti-blocking properties. As a technical idea. As a means for forming an appropriate concave-convex shape on the release agent layer, the release agent layer contains inorganic particles and/or polymer particles as fine particles. However, if you simply provide a release agent layer containing particles on the base film, if it comes into contact with a solvent, the solvent will penetrate from the gap between the particles and the release agent to the gap between the release agent layer and the base film. On the interface, there is a concern that the release agent layer will peel off from the base film. Therefore, in the present invention, it can be known that in order to prevent the solvent from penetrating into the interface between the release agent layer and the base film, it is not only a matter of providing a release agent layer containing fine particles on the base film, and the A release agent layer containing no particles is arranged in between, which improves the solvent resistance and can balance the peelability and anti-blocking properties, thereby completing the present invention.

The present invention provides a release film. On at least one surface of a substrate film, a first release agent layer containing no particles and a second release agent layer containing inorganic particles and/or polymer particles as particles are sequentially laminated. The type agent layer is characterized in that the total thickness of the thickness of the first release agent layer and the thickness of the second release agent layer is 0.4~2.0μm, which protrudes from the surface of the second release agent layer The average protrusion height of the apex of the particles is above the total thickness, and the second release agent layer contains a silicone release agent.

The inorganic particles are preferably at least one selected from the group of inorganic particles consisting of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, and talc. The polymer particles are preferably made of silicone resin , Acrylic resin, polyamide resin, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, epoxy resin selected from one or more polymer resin particles group .

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

In addition, the present invention provides a laminated film having a laminated body with an adhesive layer laminated on at least one surface of a resin film, and a surface with one or more adhesive layers, and as in the scope of patent application 1 to 3. Any one of the above-mentioned release films is formed by pasting the release agent layer of the release film on the surface of the adhesive layer of the laminate. Invention effect

According to the present invention, it is possible to provide a release film for forming a ceramic original plate and a release film having excellent releasability for optical parts having various adhesive layers. The present invention can provide a release film with excellent release properties. Its peeling force is small, and the peeling force is not easy to increase even after a long time in the state of being attached to the adhesive layer, and due to the silicone transferred to the adhesive layer There are few components, and the adhesive force of the bonded adhesive layer is not reduced.

Hereinafter, suitable embodiments of the present invention will be described. 1 is a cross-sectional view schematically showing an example of the release film of the present invention. On one surface of a base film 1, a first release agent layer 2 containing no particles is sequentially laminated, containing inorganic particles. And/or the second release agent layer 4 of the particles 3 composed of polymer 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 it may, for example, be a polyester resin film, a polyamide resin film, a polyimide resin film, and a polyimide resin film. Olefin resin film, polyvinyl chloride resin film, polystyrene resin film, acrylic resin film, acetate resin film, polyphenylene sulfide resin film, etc. Among them, a polyester resin film is preferred in terms of characteristics such as optical properties and heat resistance, price, and quality of appearance. Examples of polyester resins include polyethylene terephthalate, polyethylene naphthalate, copolymers of polyethylene isophthalate and polyethylene terephthalate, Polybutylene terephthalate, etc. Among these materials, polyethylene terephthalate (PET) is particularly preferred from the viewpoint of cost and optical characteristics. In addition, from the viewpoint of optical characteristics, a uniaxially stretched or biaxially stretched product of optical polyethylene terephthalate is preferred. In addition, if necessary, the surface of the base film 1 may be subjected to easy adhesion treatments such as surface modification by plasma discharge or corona discharge, application of an anchoring agent, and the like.

Although the thickness of the base film 1 is not particularly limited, considering the ease of handling as the release film 5 and the curling of the release film 5 in the form of a roll, the thickness of the base film 1 is preferably about 10 to 200 μm.

In the release film of the present invention, on at least one surface of the base film 1, a first release agent layer 2 containing no particles is sequentially laminated, containing inorganic particles and/or polymer particles. The second release agent layer 4 of the particles 3. In order to improve the solvent resistance of the release agent-treated surface of the release film, the first release agent layer 2 functions to adhere the base film 1 and the second release agent layer 4 containing particles 3, and also It has a function as a release agent (when the release film is peeled from the adhesive layer, etc., due to the stress during peeling, the release agent layer film is slightly deformed as an elastic body, causing the interface between the adhesive layer and the release agent layer The function of stress concentration) layer.

The release agent used in the first release agent layer 2 may, for example, be a silicone type release agent. The silicone release agent can be exemplified by conventional silicone release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and free radical polymerization type. Products commercially available as addition reaction type silicone release agents, for example, KS-776A, KS-776L, KS-847, KS-847T, KS-779H, KS-837, KS-778, KS-830, KS-774, KS-3565, X-62-2829, KS-3650, KNS-3051, KNS-320A, KNS-316, KNS-3002, X-62-1387 (Shin-Etsu Chemical Co., Ltd. Company), 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 Toray Dow Corning Co., Ltd.), TPR-6722, TPR-6721, TPR-6702, TPR-6700, TPR-6600, SL6625 (Momentive Advanced Materials Company system) and so on. As a condensation reaction type commercially available product, for example, SRX-290, SYLOFF-23 (manufactured by Toray Dow Corning Co., Ltd.), YSR-3022 (manufactured by Momentive Advanced Materials Co., Ltd.), and the like can be mentioned. As cationic polymerization type products commercially available, for example, TPR-6501, TPR-6502, TPR-6500, UV9300, VU9315, UV9430 (manufactured by Momentive Advanced Materials), X62-7622, X-62-7660, X-62-7655 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. As a product marketed as a radical polymerization type, KF-2005, X62-7205 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc. can be mentioned, for example. As a release agent with few silicone components transferred to the adhesive layer, a silicone release agent that does not contain light-peelable additives (silicone that does not contain an organic functional group involved in the addition reaction, for example, poly Dimethylsiloxane, etc.).

Silicone-based release agents can be used alone or in a mixture of multiple varieties. In addition, components other than silicone-based release agents such as a silane coupling agent, an antistatic agent, and a wettability improver may be added, and it can be determined in consideration of releasability, coatability, curability, and the like. The coating of the release agent is performed using a conventional method, and is not particularly limited, and examples thereof include a Meyer bar coating method, a gravure coating method, a reverse roll coating method, an air knife coating method, and a multi-stage roll method. The curing method of the silicone release agent may, for example, be heating curing, ultraviolet curing, electron beam curing, heating and ultraviolet irradiation, etc., as long as an appropriate method is selected and adopted according to the type of silicone release agent. The thickness of the first release agent layer 2 is not particularly limited, but in order to ensure sufficient solvent resistance, it is preferably 0.1 μm or more. The total thickness of the thickness of the first release agent layer 2 containing no particles and the thickness of the second release agent layer 4 containing the particles 3 (the average thickness of the part without the particles 3) (total thickness of the release agent layer) The adjustment can be made within the range of 0.4 to 2.0 μm.

In the present invention, on at least one surface of the base film, a first release agent layer 2 containing no particles 2 and a second release agent layer 4 containing particles 3 are sequentially laminated. The particles 3 are used in the following situations: Even if the thickness of the release agent layer containing silicone release agent is increased, the release agent layer does not stick after being attached to the back of the release film. Concave and convex shapes are formed on the surface of the release agent layer 4. Examples of the inorganic fine particles and/or polymer fine particles of the anti-blocking fine particles 3 include inorganic fine particles which are inorganic compound fine particles or polymer fine particles which are polymer resin fine particles. Inorganic fine particles and polymer fine particles may be used either, or both may be used at the same time. The inorganic fine particles are preferably one or more selected from the group of inorganic particles consisting of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, and talc. In addition, the polymer particles are preferably made of silicone resins, acrylic resins, polyamide resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene resins, and epoxy resins. One or more selected from the group of composed polymer resin particles. The shape of the particles 3 is not particularly limited, and can be any of spherical, rod-shaped, scaly, hemispherical, convex lens-shaped, mushroom-shaped, amorphous, etc. Since it can improve the anti-blocking performance, it is preferably spherical or Approximately spherical shape. The volume-based average particle size of the particles needs to be greater than the thickness of the second release agent layer 4. The height from the surface of the second release agent layer 4 to the apex of the protruding particles 3 (the protruding height of the particles 3) is selected to be in the first The total thickness of the release agent layer 2 and the second release agent layer 4 may be fine particles having a volume-based average particle diameter or more. The apex of the fine particles 3 may be the point farthest from the surface of the second release agent layer 4, and it does not matter whether the apex is sharp or round.

The release agent that functions as the binder resin of the fine particles 3 and forms the second release agent layer 4 may, for example, be a silicone-based release agent. The silicone release agent can be exemplified by conventional silicone release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and free radical polymerization type. Silicone-based release agents can be used alone or in a mixture of multiple varieties. In addition, components other than silicone-based release agents such as silane coupling agents, antistatic agents, and wettability improvers can also be added, and it can be determined in consideration of releasability, coating properties, curability, and the like. The silicone release agent forming the second release agent layer 4 may be the same as or different from the release agent forming the first release agent layer 2.

The particles 3 are mixed into a release agent containing a silicone-based release agent forming the second release agent layer 4 and coated on the first release agent layer 2. A part (upper part) of the particles 3 protrudes from the thickness of the second release agent layer 4 (the average thickness of the part without the particles 3). The release agent of the second release agent layer 4 may be thinly attached to the upper surface of the particles 3, or may not be attached. The lower part of the particles 3 is embedded in the second release agent layer 4 and does not contact the base film 1. This is because the first release agent layer 2 containing no particles is interposed.

The method of mixing and dispersing the microparticles 3 into the release agent of the second release agent layer 4 may be performed by a known method according to the type of the release agent and the microparticles. In the case of a system in which the particles are easily dispersed in the release agent, use a manual tool such as a spatula to stir and mix. Even if it is a combination or easily dispersed system in which the particles are not easily dispersed in the release agent, when the release agent and the amount of particles are large, a homogenizer or a high-speed stirrer or other disperser can be used for dispersion and mixing. In addition to fine particles and release agents, colorants, antistatic agents, leveling agents, adhesion improvers, etc. may be added as needed.

The method for forming the second release agent layer 4 containing the fine particles 3 is to apply and set the release agent containing the fine particles 3 on the first release agent layer 2 formed on the base film 1. The coating method is not particularly limited, and it may be selected from conventional coating methods according to the viscosity and coating amount of the release agent containing the fine particles 3. As an example, a Meyer bar coating method, a gravure coating method, a reverse roll coating method, an air knife coating method, a multi-stage roll method, etc. may be mentioned.

The curing or curing of the second release agent layer 4 containing the fine particles 3 can be performed according to the type of the release agent. For example, it is possible to perform heat drying to remove the solvent or water, etc., to perform curing of the release agent layer by ultraviolet irradiation, electron beam irradiation, or the like.

The thickness of the second release agent layer 4 is not particularly limited. In order to sufficiently ensure the function of the binder resin as the fine particles 3, it is preferably 25% or more of the volume-based average particle diameter of the fine particles 3. If the total thickness of the thickness of the first release agent layer 2 and the thickness of the second release agent layer 4 is less than 0.4 μm, the peeling force is likely to increase. In addition, the upper limit of the total thickness of the sum of the thickness of the first release agent layer 2 and the thickness of the second release agent layer 4 is not particularly problematic, but the thickness of the first release agent layer 2 and the second release agent layer 4 are increased. In the case of the total thickness of the addition of the thickness of the agent layer 4, it is preferable because of the problem of higher cost and the problem of whitening the appearance of the release film due to the increase in the volume-based average particle diameter of the particles 3 Control to about 2μm.

When the release film 5 of the present invention is used for the molding release sheet of the original plate used in the manufacture of various ceramic electronic components, the original plate is coated and dried by a slurry in which ceramic particles are dispersed in an organic solvent. And formed. In the release film 5 used for the purpose of protecting the original plate, solvent resistance is required. The release film 5 of the present invention is provided with a first release agent layer 2 containing no particles between the base film 1 and the second release agent layer 4 containing particles 3. Therefore, even if the solvent penetrates from the gap between the release agent of the second release agent layer 4 and the particles 3 to the interface between the second release agent layer 4 and the first release agent layer 2, the solvent cannot Upon reaching the interface between the first release agent layer 2 and the base film 1, the first release agent layer 2 does not peel off from the base film 1, and the solvent resistance is also good. In addition, the release film 5 of the present invention is not limited to the original plate, but can also be applied to the use of protecting the surface of a coating film in which various powders such as conductor paste and insulator paste are dispersed or a coating film containing a solvent.

Fig. 2 is a cross-sectional view schematically showing a first embodiment of the laminated film of the present invention. The adhesive optical film 8 of FIG. 2 is a use of 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 in FIG. 1, the optical film 7 is bonded via the adhesive layer 6. The manufacturing method of the said adhesive optical film 8 can apply and dry a solvent-type adhesive on the release film 5, and can bond the optical film 7 together. The release film 5 used for the purpose of protecting the adhesive layer 6 described above requires solvent resistance. The release film 5 of the present invention is provided with a first release agent layer 2 containing no particles between the base film 1 and the second release agent layer 4 containing particles 3. Therefore, even if the solvent penetrates from the gap between the release agent of the second release agent layer 4 and the particles 3 to the interface between the second release agent layer 4 and the first release agent layer 2, the solvent cannot Upon reaching the interface between the first release agent layer 2 and the base film 1, the first release agent layer 2 does not peel off from the base film 1, and the solvent resistance is also good. The laminate containing the adhesive layer 6 may contain one or two or more resin films and one or two or more adhesive layers. For example, the adhesive layer 6 may be provided on both surfaces of the optical film 7 and the release film 5 may be bonded to each adhesive layer 6. As another manufacturing method, the release film 5 may be bonded to the laminate 10 in which the adhesive layer 6 is provided on one surface of the optical film 7. Alternatively, after applying a solvent-free adhesive, between the release film 5 and the optical film 7, the adhesive layer 6 may be cured by light, heat, or the like. During use, by peeling the release film 5 from the adhesive optical film 8, the laminate 10 is separated from the release film 5 and the surface of the adhesive layer 6 can be exposed. Generally, the adhesive force between the optical film 7 and the adhesive layer 6 is larger than the peeling force when the release film 5 is peeled from the adhesive layer 6.

In addition, FIG. 3 is a cross-sectional view schematically showing a second embodiment of the laminated film of the present invention. The optical adhesive sheet 9 of FIG. 3 is formed by bonding the release film 5 of the present invention for protecting the adhesive layer 6 on the adhesive layer 6 used for bonding the touch panel component or the optical component. The optical adhesive sheet 9 has a form in which the adhesive layer 6 is sandwiched by two release films 5. In the manufacturing method of the optical adhesive sheet 9 described above, a solvent-based adhesive is usually applied to one release film 5, and after drying, the other release film 5 is laminated. The above-mentioned release film 5 used for the purpose of protecting the adhesive layer 6 requires solvent resistance. Since the release film 5 of the present invention is also excellent in solvent resistance, it can be applied to the application of protecting the adhesive layer 6.

The adhesive used in the adhesive layer 6 of the laminated film of the present invention may be aqueous, non-aqueous (solvent-based), or solvent-free. The adhesive may be any of acrylic adhesives, silicone adhesives, rubber adhesives, urethane adhesives, and the like. Acrylic adhesives are preferred because they have excellent transparency and weather resistance. The resin film used in the laminated film is not limited to the optical film 7, and may be an opaque resin film. As an optical film, a polarizing film, a retardation film, an anti-reflection film, an anti-glare (anti-glare) film, an ultraviolet absorption film, an infrared absorption film, an optical compensation film, a brightness improvement film, a high transparent film, etc. are mentioned. The laminated film of the present invention is a laminated film formed by attaching the release agent layer of the release film to the surface of the adhesive layer, and it may be a laminated film formed by only the release film 5 and the adhesive layer as shown in FIG. 3 The laminated film constituted by 6 may also be a laminated film containing a resin film like the optical film 7 (support of the adhesive layer 6) and the like as shown in FIG. 2. Example

Hereinafter, the present invention will be specifically described based on examples.

(The release film of Example 1) Corona treatment is applied to one surface of a base film composed of a polyester film with a thickness of 38μm. On the corona treated surface, a Meyer rod is used to coat the surface with a thickness of 0.1μm after drying. Reactive silicone release agent A (combined with 10 parts by weight of Toray Dow Corning SRX-211, 0.1 parts by weight of platinum catalyst SRX212 and 90 parts by weight of toluene/ethyl acetate 50/50 mixed solvent), Use a hot air loop dryer at 120°C to heat for 1 minute. After that, on the silicone-based release agent coating surface, use a Meyer rod to coat the addition-reactive silicone release agent B to a thickness of 0.9 μm after drying to release the addition-reactive silicone release agent. Agent B (compared to 30 parts by weight of LTC-1056L manufactured by Toray Dow Corning, mixed with 1 part by weight of platinum catalyst SRX212, 70 parts by weight of toluene/ethyl acetate 50/50 mixed solvent) and 0.0166 parts by weight of average particle size (Volume-based average particle size) 2μm silicone resin polymer particles (manufactured by Momentive Advanced Materials Co., Ltd., trade name: Tospearl (registered trademark) 120) mixed with hot air at 120°C and circularly dried The device was heated for 1 minute to obtain the release film of Example 1.

(The release film of Example 2) The thickness after drying of the addition reaction type silicone release agent A is 0.3μm, and the thickness after drying of the addition reaction type silicone release agent B is 0.7μm, and the silicone resin polymer particles (Momento Product name: Tospearl (registered trademark) 120) is replaced by amorphous silicon dioxide (manufactured by Fuji Silysia Co., Ltd., product name: Sylysia (registered trademark) 310P) with a volume-based average particle size of 2.7 μm. Otherwise In the same manner as in Example 1, the release film of Example 2 was obtained.

(The release film of Example 3) The release film of Example 3 was obtained in the same manner as in Example 1, except that the thickness after drying of the addition reaction type silicone-based release agent B was 0.4 μm.

(The release film of Example 4) The thickness after drying of the addition reaction type silicone release agent A is 0.3μm, and the thickness after drying of the addition reaction type silicone release agent B is 1.7μm, and the silicone resin polymer particles (step Tospearl (registered trademark) 120) is replaced by silicone resin polymer particles with a volume-based average particle size of 4.5 μm (manufactured by Momentive Advanced Materials, product name: Tospearl (registered trademark) 145 ), except for this, the release film of Example 4 was obtained in the same manner as in Example 1.

(The release film of Comparative Example 1) A release film of Comparative Example 1 was produced in the same manner as in Example 1, except that the addition reaction type silicone-based release agent A was not provided.

(The release film of Comparative Example 2) The release film of Comparative Example 2 was obtained in the same manner as in Example 1, except that the thickness after drying of the addition reaction type silicone-based release agent B was 1.2 μm.

(The release film of Comparative Example 3) Corona treatment is applied to one surface of a base film composed of a polyester film with a thickness of 38μm, and a Meyer rod is used on the corona treated surface to coat only the addition reaction with a thickness of 0.2μm after drying. Type silicone release agent B was heated in a hot-air loop dryer at 120°C for 1 minute to obtain a release film of Comparative Example 3.

(Check whether there is adhesion) Stack 3 release films to make a sample, which is sandwiched between 2 stainless steel plates (SUS304). ^{A load of 20g/cm 2} {0.196N/cm ² } is applied to this sample, and it is left in an environment of 23°C and 50%RH for 24 hours in this state. After that, take out the 3 overlapped release films, and check the adhesion state by peeling off the release films one by one by hand. The non-blocking and easy peeling of the release film was evaluated as good anti-blocking properties (○), and the resistance to peeling of the release film was evaluated as poor anti-blocking properties (×).

(Measurement of Peeling Force) A polyester adhesive tape (manufactured by Nitto Denko Co., Ltd., trade name: polyester tape No. 31B) was attached to the surface of the release agent layer of the release film, under a load of ^{20 g/cm 2} After aging at 70°C for 20 hours, use a desktop precision universal testing machine (manufactured by Shimadzu Corporation, Autograph (registered trademark)), and the peel strength when peeling is performed at a peeling speed of 300mm/min and a peeling angle of 180° as peeling The force (mN/50mm) was measured.

(Determination of residual adhesion rate) After the above (measurement of peeling force) test, the adhesive tape peeled from the release film was pressed onto the adherend (stainless steel plate) with a roller, and then placed in an environment of 23°C and 55% RH for 1 hour, Using a desktop precision universal testing machine (manufactured by Shimadzu Corporation, Autograph (registered trademark)), the peeling force when peeling from the adherend was measured at a peeling speed of 300 mm/min and a peeling angle of 180°, and it was taken as the residual adhesive relay. In addition to this, the peel strength when the unused adhesive tape is pressed onto the adherend of the same material and peeled off was also measured as the standard adhesive strength. The residual adhesion rate is calculated by the residual adhesion rate = (residual adhesion) / (standard 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 (measurement of peeling force) test with the finger pad 3 times, the wiped part was visually observed. The presence or absence of the release agent layer peeling off the base film was visually confirmed, and the release agent layer was almost not peeled off was evaluated as (○), and the release agent layer was clearly peeled off as evaluated (×).

(Confirmation of solvent resistance of release agent layer) Using a non-woven fabric impregnated with ethyl acetate (Bencotto (registered trademark) M-1 manufactured by Asahi Kasei Textile Co., Ltd.), the surface of the release agent layer of the release film was wiped back and forth once with a weight load of 200 g. After that, the surface of the release agent layer of the release film was visually observed to confirm the solvent resistance of the release agent layer of the release film. The surface of the release agent layer was visually confirmed, and it was judged that there was no change in appearance as (○), and the release agent layer was judged as (×).

(Result of measurement and confirmation test) The results of various measurements and confirmation tests of the release films obtained in Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1.

[Table 1] Peeling force (mN/50mm) Residual bonding rate (%) Adhesion Adhesion of the release agent layer Solvent resistance of the release agent layer Example 1 48 98 ○ ○ ○ Example 2 55 98 ○ ○ ○ Example 3 63 97 ○ ○ ○ Example 4 46 97 ○ ○ ○ Comparative example 1 50 97 ○ ○ X Comparative example 2 87 95 X ○ ○ Comparative example 3 92 97 ○ ○ ○

(to sum up) The release films of Examples 1 to 4 related to the present invention showed a very small peeling force and a very high residual adhesion rate. In addition, in the adhesion confirmation test of the release films of Examples 1 to 4, there was no adhesion between the second release agent layer and the back of the release film, and the second release agent layer containing particles was dense Compatibility and solvent resistance are also good. In contrast, the release film of Comparative Example 1 did not have a first release agent layer containing no particles, and formed a structure in which the release agent layer containing particles was in contact with the base film, and the result of solvent resistance was poor. In addition, in the release film of Comparative Example 2, the unevenness of the second release agent layer containing fine particles was small, the release film was stuck, and the peeling force was also increased. In addition, in the release film of Comparative Example 3, only a silicone release agent containing no particles was applied in a normal coating amount to form a release agent layer. As a result, the release force was higher than that of Example 1 of the present invention. The release film of ~4 is larger.

1: Base film 2: The first release agent layer 3: particles 4: The second release agent layer 5: Release film 6: Adhesive layer 7: Optical film 8: Adhesive optical film 9: Optical adhesive sheet 10: Layered body

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

1: Base film

2: The first release agent layer

3: particles

4: The second release agent layer

5: Release film

Claims (2)

A release film, on at least one surface of a substrate film, a first release agent layer containing no particles and a second release agent layer containing inorganic particles and/or polymer particles as particles are sequentially laminated, It is characterized by The inorganic fine particles are one or more selected from the group of inorganic particles consisting of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, and talc, The polymer particles are composed of silicone resins, acrylic resins, polyamide resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene resins, and epoxy resins Choose more than one type from the group of polymer resin particles, The first release agent layer contains a silicone release agent, and does not contain polydimethylsiloxane as a light-release additive component, The thickness of the first release agent layer and the thickness of the second release agent layer add up to a total thickness of 0.4-2.0 μm, The volume-based average particle size of the particles is greater than the thickness of the second release agent layer, The average protrusion height from the surface of the second release agent layer to the apex of the protruding particles is greater than the total thickness, and the second release agent layer contains a silicone release agent. The release film according to claim 1, wherein the base film is a polyester film.

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