JP6480295B2 - Release film with excellent releasability - Google Patents

Description

  The present invention relates to a release film used for protecting an adhesive layer in an optical member having various adhesive products and an adhesive layer. More specifically, the peeling force is small, and even when time passes in the state of being bonded to the pressure-sensitive adhesive layer, the peeling force is hardly increased, and the transfer of the silicone component to the pressure-sensitive adhesive layer is small, and thus bonding is performed. The present invention relates to a release film that does not decrease the adhesive strength of the pressure-sensitive adhesive layer and has excellent peelability.

  Conventionally, release films (sometimes referred to as release films) have been used for various applications. Above all, it has a pressure-sensitive adhesive layer used in the production of green sheet molding release films, polarizing plates, optical filters, flat panel displays, etc. used in the production of various ceramic electronic parts such as ceramic multilayer capacitors and ceramic substrates. Widely used for release films for optical members, touch panel members, release films for adhesive layers for bonding optical members, and the like.

  Green sheets used in the production of various ceramic electronic components such as ceramic multilayer capacitors and ceramic substrates are becoming thinner as ceramic multilayer capacitors become smaller and larger in capacity. When a green sheet is peeled from a release film, if the release force of the release film is large, the green sheet is damaged. Therefore, a release film having a smaller peel force than the conventional one is required.

On the other hand, in an optical member such as a polarizing plate and a retardation plate that are members constituting a liquid crystal display, in order to protect an adhesive layer for use in bonding with optical members formed on the optical member or with other members A release film is used.
The release film used for the application needs to be able to be peeled lightly even if the peel area is large, as the size of the optical member such as a polarizing plate and the release film increase as the display becomes larger. Therefore, there is a demand for a release film having a smaller peeling force than conventional ones. Moreover, about the adhesive layer for optical members for bonding the structural member and optical members of a touch panel, with thinning of tablet PC, a tablet terminal, a touch panel, etc., even a thin adhesive layer of an optical member A pressure-sensitive adhesive layer having a weak cohesive force is used so as to follow a step (for example, a step of frame printing used for a cover glass of a portable terminal). However, when a pressure-sensitive adhesive layer having a weak cohesive force is used, the release film having a smaller peeling force than conventional ones will be deformed if the release force of the release film is too large. Is required.

As described above, a release film for forming a ceramic green sheet and a release film for an optical member having various pressure-sensitive adhesive layers are required to have a release film having a smaller peeling force than conventional ones. Against this background, Patent Document 1 proposes a release film using a cured silicone containing silicone having only one vinyl group in the molecule.
Further, in Patent Document 2, an oligomer precipitation preventing layer is applied to one side of a polyester film, and a release layer containing a solventless addition reaction curable silicone is provided thereon, and the tape peeling force is 15 mN / cm or less. In addition, a release film having a migration evaluation adhesion rate of silicone components of 90% or more has been proposed.
Furthermore, in patent document 3, the release which performed the heat processing for 20 hours or more in 50-65 degreeC environment using the addition reaction type silicone which does not add the light peeling component, such as polydimethylsiloxane which does not have a functional group. A release film having a peeling force of acrylic pressure-sensitive adhesive of 0.15 N / 50 mm or less and a residual adhesive rate of 90% or more has been proposed.

In each of Patent Documents 1 to 3, a release film is proposed that has a small peeling force and does not reduce the adhesive strength of the bonded adhesive layer. However, since the release film described in Patent Document 1 uses a cured silicone containing silicone having only one vinyl group in the molecule, silicone having only one vinyl group unless the vinyl group is completely reacted. Is likely to move to the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer is reduced.
Moreover, about the release film of patent document 2, it is different from the conventional release film that the precipitation prevention layer of an oligomer is provided. However, since solvent-free addition reaction curable silicone is used, the release performance falls within the category of conventional release films. Furthermore, the release film described in Patent Document 3 is lightly peeled by aging addition-reactive silicone to which no lightly peeling component is added. In this case, a release film that does not decrease the adhesive strength of the bonded adhesive layer is obtained for light peeling, but it is difficult to further reduce the peeling force.

  The release film described in Patent Document 4 is obtained by applying a silicone release layer containing inert particles having a predetermined particle diameter to a polyester film to a predetermined thickness. Blocking that occurs when the silicone release layer is thickened (a phenomenon in which when the release film is rolled into a roll, the back surface of the release film and the release layer are pseudo-bonded and cannot be wound well) This is solved by putting inert particles in the silicone release layer. However, since the silicone release layer is discontinuous due to the inert particles, when the solvent comes into contact with the solvent, the solvent may permeate the interface between the inert particles and the silicone, and the silicone may fall off. In addition, when adding a release film to protect the surface of the pressure-sensitive adhesive layer in order to add inert particles having a particle size larger than the thickness of the silicone release layer, the inert particles are placed on the pressure-sensitive adhesive layer side. It may adhere and reduce the adhesive strength of the adhesive layer.

JP 2008-265227 A JP 2012-136612 A JP 2006-007689 A JP2013-208897A

  In the present invention, the peeling force is small, and even when time passes in the state of being bonded to the pressure-sensitive adhesive layer, the peeling force is hardly increased, and the silicone component is less transferred to the pressure-sensitive adhesive layer, and thus bonded. It is an object of the present invention to provide a release film that does not decrease the adhesive strength of the pressure-sensitive adhesive layer and has excellent peelability.

  As a result of intensive studies to solve these problems, in order not to reduce the adhesive strength of the pressure-sensitive adhesive layer, a release film using a silicone-based release agent (sometimes called a release agent) is used. It has been found that there is a need for less silicone transfer to the layer. In addition, even when using a silicone release agent with little silicone migration to the pressure-sensitive adhesive layer, as a result of studying to reduce the peel force, by increasing the thickness of the release agent layer to a specific thickness or more It was found that the peel force can be reduced. However, when the thickness of the release agent layer is increased, the release film is wound into a roll shape, and when the release agent layer is combined with the back surface of the release film, blocking occurs, and the release agent layer is released. It was found that the film could not be wound up in a roll. In the production process, the base film used for the release film contains lubricant particles in order to prevent blocking even when the base film is wound into a roll shape. A film is being formed. For this reason, on the back surface of the release film, the surface of the base film has an uneven structure. By increasing the thickness of the release agent layer, the uneven structure on the surface of the base film is released. The filling of the agent layer is considered to cause the blocking.

  In addition, the present invention has been completed by intensively studying a method for achieving both peelability and blocking resistance. In the present invention, the thickness of the release agent layer is set to 0.4 μm or more in order to reduce the peeling force even when a release agent with little migration of the silicone component to the pressure-sensitive adhesive layer is used. Moreover, in order to prevent blocking between the release agent layer and the back surface of the release film, the present invention forms a concavo-convex shape having an appropriate surface roughness on the release agent layer, thereby providing releasability and blocking resistance. The technical idea is to achieve both. As a means for forming an appropriate uneven shape in the release agent layer, the release agent layer contains inorganic fine particles and / or polymer fine particles as fine particles. However, by simply providing a release agent layer containing fine particles on the base film, when the solvent comes into contact with the solvent, the solvent penetrates into the interface between the release agent layer and the base film from the gap between the fine particles and the release agent. The release agent layer may be peeled off from the base film. For this reason, in the present invention, in order to prevent the solvent from penetrating to the interface between the release agent layer and the base film, the base film is not simply provided with a release agent layer containing fine particles, and no fine particles are contained therebetween. By providing the release agent layer, it was found that the solvent resistance was improved and that both the peelability and the blocking resistance were compatible, and the present invention was completed.

In the present invention, the first release agent layer containing no fine particles on at least one surface of the base film, and the second release agent layer containing inorganic fine particles and / or polymer fine particles as fine particles, The release films are laminated in this order, and 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. 0 μm, the tops of the fine particles protrude from the surface of the second release agent layer, and the average protrusion height from the surface of the second release agent layer to the tops of the fine particles is A release film having a total thickness or more and wherein the second release agent layer contains a silicone release agent is provided.

  The inorganic fine particles are at least one selected from the group of inorganic particles consisting of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, talc, and the polymer fine particles are silicone resin, acrylic resin, polyamide It is preferable that it is 1 or more types selected from the polymer resin particle group which consists of resin based, polyester based resin, polyethylene based resin, polypropylene based resin, polystyrene based resin and epoxy based resin.

  Moreover, it is preferable that the said base film is a polyester film.

  In addition, the present invention provides a laminate having the surface of one or more pressure-sensitive adhesive layers in which a pressure-sensitive adhesive layer is laminated on at least one surface of the resin film, and the release film according to any one of claims 1 to 3 And a laminated film obtained by bonding the release agent layer of the release film to the surface of the pressure-sensitive adhesive layer of the laminate.

  ADVANTAGE OF THE INVENTION According to this invention, the mold release film for shaping | molding of a ceramic green sheet and the mold release film excellent in the peelability for optical members which have various adhesive layers can be provided. The release film of the present invention has a small peel force, and even when time passes in the state of being bonded to the pressure-sensitive adhesive layer, the peel force is hardly increased, and the silicone component does not migrate to the pressure-sensitive adhesive layer. It is possible to provide a release film excellent in releasability that does not reduce the adhesive strength of the bonded pressure-sensitive adhesive layer.

It is sectional drawing which shows an example of the release film of this invention typically. It is sectional drawing which shows typically the 1st form example of the laminated | multilayer film of this invention. It is sectional drawing which shows typically the 2nd form example of the laminated | multilayer film of this invention.

Hereinafter, preferred embodiments of the present invention will be described.
FIG. 1 is a cross-sectional view schematically showing an example of a release film of the present invention, and includes a first release agent layer 2 containing no fine particles, inorganic fine particles, and / or one side of a base film 1. Alternatively, a second release agent layer 4 containing fine particles 3 made of polymer fine particles is laminated in this order.

In the release film 5 of the present invention, the resin film used as the base film 1 may be selected according to the use, but the polyester resin film, polyamide resin film, polyimide resin film, polyolefin resin film, polyvinyl chloride resin film. , Polystyrene resin film, acrylic resin film, acetate resin film, polyphenylene sulfide resin film, and the like.
Among these, a polyester resin film is preferable from the viewpoints of characteristics such as optical characteristics and heat resistance, price, and appearance. Examples of the polyester resin include polyethylene terephthalate, polyethylene naphthalate, a copolymer of polyethylene isophthalate and polyethylene terephthalate, and polybutylene terephthalate. Among these, polyethylene terephthalate (PET) is particularly preferable from the viewpoint of cost and optical properties. Also, from the viewpoint of optical characteristics, monoaxially stretched or biaxially stretched polyethylene terephthalate for optics is preferable.
Further, if necessary, the surface of the base film 1 may be subjected to easy adhesion treatment such as surface modification by plasma discharge or corona discharge, application of an anchor coating agent, and the like.

  The thickness of the base film 1 is not particularly limited, but assuming the ease of handling as the release film 5 and winding the release film 5 in a roll shape, the thickness of the base film 1 is About 10-200 micrometers is preferable.

In the release film of the present invention, the second release agent containing the first release agent layer 2 containing no fine particles and the fine particles 3 composed of inorganic fine particles and / or polymer fine particles on at least one surface of the base film. The mold material layer 4 is laminated in this order.
The first release agent layer 2 bonds the base film 1 and the second release agent layer 4 containing the fine particles 3 in order to improve the solvent resistance of the release agent-treated surface of the release film. Function as a release agent (when releasing a release film from an adhesive layer or the like, the release layer is slightly deformed as an elastomer by the stress at the time of release, and the adhesive layer and This layer also has a function of concentrating stress on the interface of the release agent layer.

  Examples of the release agent used for the first release agent layer 2 include silicone release agents. Examples of the silicone release agent include known silicone release agents such as an addition reaction type, a condensation reaction type, a cationic polymerization type, and a radical polymerization type. Examples of products that are commercially available as addition reaction type silicone release agents include KS-776A, KS-776L, KS-847, KS-847T, KS-779H, KS-837, KS-778, and KS-830. , KS-774, KS-3565, X-62-2829, KS-3650, KNS-3051, KNS-320A, KNS-316, KNS-3002, X-62-1387 (manufactured by Shin-Etsu Chemical Co., Ltd.), 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-6 722, TPR-6721, TPR-6702, TPR-6700, TPR-6600, SL6625 (manufactured by Momentive Performance Materials). Examples of the products marketed as the condensation reaction type include SRX-290, SYLOFF-23 (manufactured by Toray Dow Corning), YSR-3022 (manufactured by Momentive Performance Materials). Examples of products marketed as a cationic polymerization type include TPR-6501, TPR-6502, TPR-6500, UV9300, VU9315, UV9430 (manufactured by Momentive Performance Materials), X62-7622, X-62. -7660, X-62-7655 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. Examples of products marketed as radical polymerization types include KF-2005, X62-7205 (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like. Silicone mold release agent that does not contain a light release additive component (silicone that does not have an organic functional group involved in an addition reaction, such as polydimethylsiloxane) as a mold release agent with little migration of the silicone component to the adhesive layer Is mentioned.

One type of silicone release agent may be used alone, or a plurality of types may be mixed and used. In addition, components other than silicone release agents such as a silane coupling agent, an antistatic agent, and a wettability improver may be added, and may be determined in consideration of releasability, coatability, curability, and the like. The release agent may be applied by a known method and is not particularly limited, and examples thereof include a Mayer bar method, a gravure method, a reverse roll method, an air knife method, and a multistage roll method. Examples of curing methods for silicone mold release agents include methods such as heat curing, ultraviolet curing, electron beam curing, and combined use of heating and ultraviolet irradiation. Select a suitable method according to the type of silicone mold release agent. And adopt it. Although the thickness of the 1st mold release agent layer 2 is not specifically limited, In order to ensure sufficient solvent resistance, it is preferable that it is 0.1 micrometer or more.
The total sum of the thickness of the first release agent layer 2 containing no fine particles and the thickness of the second release agent layer 4 containing the fine particles 3 (average thickness of the portion without the fine particles 3) The thickness (total thickness of the release agent layer) may be adjusted within a range of 0.4 to 2.0 μm.

In the present invention, the first release agent layer 2 not containing fine particles and the second release agent layer 4 containing fine particles 3 are laminated in this order on at least one surface of the base film. . In order to prevent the fine particles 3 from blocking when the release agent layer is combined with the back surface of the release film, even if the release agent layer containing the silicone release agent is increased in thickness, It is used for forming an uneven shape on the surface of the release agent layer 4.
Examples of the inorganic fine particles and / or polymer fine particles that are the fine particles 3 for blocking prevention include inorganic fine particles that are fine particles of an inorganic compound and polymer fine particles that are fine particles of a polymer resin. Either inorganic fine particles or polymer fine particles may be used, or both may be used in combination. The inorganic fine 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. In addition, the polymer fine particles are selected from a group of polymer resin particles composed of silicone resin, acrylic resin, polyamide resin, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, and epoxy resin. The above is preferable.
The shape of the fine particles 3 is not particularly limited, and may be any of spherical, rod-like, scale-like, hemispherical, convex lens-like, mushroom-like, and indeterminate shapes. Since the performance is increased, it is more preferable.
The volume-based average particle diameter of the fine particles is preferably larger than the thickness of the second release agent layer 4, and the height to the top of the fine particles 3 protruding from the surface of the second release agent layer 4 (fine particles 3 Of the volume-based average particle diameter may be selected so that the height of the protrusion is equal to or greater than the total thickness of the first release agent layer 2 and the second release agent layer 4. The vertex of the fine particles 3 may be a point farthest from the surface of the second release agent layer 4, and it does not matter whether the vertex is pointed or rounded.

Examples of the release agent that functions as a binder resin for the fine particles 3 and forms the second release agent layer 4 include silicone-based release agents. Examples of the silicone release agent include known silicone release agents such as an addition reaction type, a condensation reaction type, a cationic polymerization type, and a radical polymerization type.
One type of silicone release agent may be used alone, or a plurality of types may be mixed and used. In addition, components other than silicone release agents such as a silane coupling agent, an antistatic agent, and a wettability improver may be added, and may be determined in consideration of releasability, coatability, curability, and the like. The silicone release agent that forms the second release agent layer 4 may be the same silicone release agent as the release agent that forms the first release agent layer 2, or may be different.

  The fine particles 3 are mixed with a release agent containing a silicone release agent that forms the second release agent layer 4, and are applied onto the first release agent layer 2. A part (upper part) of the fine particles 3 protrudes from the thickness of the second release agent layer 4 (an average thickness of a part without the fine particles 3). The release agent of the second release agent layer 4 may be thinly attached to the upper surface of the fine particles 3 or may not be attached. The lower part of the fine particles 3 is embedded in the second release agent layer 4 but is not in contact with the base film 1. This is because the first release agent layer 2 containing no fine particles is interposed.

  The mixing / dispersing method of the fine particles 3 in 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 fine particles. What is necessary is just to stir and mix with manual tools, such as a spatula, if it is a system in which microparticles | fine-particles are easy to disperse | distribute to a mold release agent. Even if the release agent is a combination in which fine particles are difficult to disperse or a system that is easy to disperse, or if the release agent and fine particles are in large quantities, they can be dispersed and mixed using a disperser such as a homogenizer or homomixer. good. In addition to the fine particles and the release agent, a colorant, an antistatic agent, a leveling agent, an adhesion improver, and the like may be added as necessary.

  The method for forming the second release agent layer 4 containing the fine particles 3 includes coating the release agent containing the fine particles 3 on the first release agent layer 2 formed on the base film 1. What is necessary is just to provide. The coating method is not particularly limited, and may be selected from known coating methods according to the viscosity and the coating amount of the release agent containing fine particles 3. Examples include the Mayer bar method, the gravure method, the reverse roll method, the air knife method, and the multi-stage roll method.

  The second release agent layer 4 containing the fine particles 3 may be cured or solidified according to the type of the release agent. For example, the solvent or water may be removed by heat drying, or the release agent layer may be cured by ultraviolet irradiation or electron beam irradiation.

  The thickness of the second release agent layer 4 is not particularly limited, but may be 25% or more of the volume-based average particle diameter of the fine particles 3 in order to sufficiently ensure the function of the fine particles 3 as a binder resin. preferable. 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 tends to increase. Further, the upper limit of the total thickness of the first release agent layer 2 and the second release agent layer 4 combined is not particularly problematic, but the first release agent layer 2 has When the total thickness of the thickness and the thickness of the second release agent layer 4 is increased, there is a problem that the cost is increased, or the release film is increased by increasing the volume-based average particle diameter of the fine particles 3. It is preferable to suppress the thickness to about 2 μm.

  When the release film 5 of the present invention is used as a release sheet for forming a green sheet used in the production of various ceramic electronic parts, the green sheet is coated with a slurry in which ceramic particles are dispersed in an organic solvent, and dried. It is formed by. Such a release film 5 used for protecting the green sheet is required to have solvent resistance. In the release film 5 of the present invention, the first release agent layer 2 containing no fine particles is provided between the base film 1 and the second release agent layer 4 containing the fine particles 3. Therefore, even if the solvent penetrates into the interface between the second release agent layer 4 and the first release agent layer 2 through the gap between the release agent of the second release agent layer 4 and the fine particles 3. Since the solvent does not reach the interface between the first release agent layer 2 and the substrate film 1, the first release agent layer 2 is not peeled off from the substrate film 1, and the solvent resistance is also good. It is. In addition, the release film 5 of the present invention is not limited to a green sheet, and is suitably used for the purpose of protecting the surface of a coating film in which various powders such as a conductor paste and an insulator paste are dispersed and a coating film containing a solvent it can.

  FIG. 2 is a cross-sectional view schematically showing a first embodiment of the laminated film of the present invention. 2 is used for the purpose of protecting the pressure-sensitive adhesive layer 6 laminated on the optical film 7 with the release film 5 of the present invention. An optical film 7 is bonded to the release film 5 of the present invention shown in FIG. In such a method for producing the optical film 8 with pressure-sensitive adhesive, the optical film 7 may be bonded after the solvent-type pressure-sensitive adhesive is applied to the release film 5 and dried. Such a release film 5 used for protecting the pressure-sensitive adhesive layer 6 requires solvent resistance. In the release film 5 of the present invention, the first release agent layer 2 containing no fine particles is provided between the base film 1 and the second release agent layer 4 containing the fine particles 3. Therefore, even if the solvent penetrates into the interface between the second release agent layer 4 and the first release agent layer 2 through the gap between the release agent of the second release agent layer 4 and the fine particles 3. Since the solvent does not reach the interface between the first release agent layer 2 and the substrate film 1, the first release agent layer 2 is not peeled off from the substrate film 1, and the solvent resistance is also good. It is. The laminate including the pressure-sensitive adhesive layer 6 can include one or more resin films and one or more pressure-sensitive 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, you may bond the release film 5 to the laminated body 10 which provided the adhesive layer 6 in the single side | surface of the optical film 7. FIG. Alternatively, the adhesive layer 6 can be cured between the release film 5 and the optical film 7 by light, heat, or the like after applying the solventless adhesive. At the time of use, by peeling the release film 5 from the adhesive optical film 8, the laminate 10 can be separated from the release film 5 and the surface of the pressure-sensitive adhesive layer 6 can be exposed. In general, the adhesive force between the optical film 7 and the pressure-sensitive adhesive layer 6 is larger than the peeling force when peeling the release film 5 from the pressure-sensitive adhesive layer 6.

  Moreover, FIG. 3 is sectional drawing which shows typically the 2nd form example of the laminated | multilayer film of this invention. The optical pressure-sensitive adhesive sheet 9 in FIG. 3 is obtained by bonding the release film 5 of the present invention to the pressure-sensitive adhesive layer 6 used for bonding a touch panel member or an optical member in order to protect the pressure-sensitive adhesive layer 6. is there. The optical adhesive sheet 9 has a form in which the adhesive layer 6 is sandwiched between two release films 5. In such a method for producing the optical pressure-sensitive adhesive sheet 9, a solvent-type pressure-sensitive adhesive is applied to one release film 5 and dried, and then the other release film 5 is bonded. Such a release film 5 used for protecting the pressure-sensitive adhesive layer 6 requires solvent resistance. Since the release film 5 of the present invention has good solvent resistance, it can be suitably used for the purpose of protecting the pressure-sensitive adhesive layer 6.

The pressure-sensitive adhesive used for the pressure-sensitive adhesive layer 6 of the laminated film of the present invention may be water-based, non-aqueous (solvent-based) or solvent-free type. As the pressure-sensitive adhesive, any of an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, and the like may be used. An acrylic pressure-sensitive adhesive is preferable because it is excellent in transparency and weather resistance.
The resin film used for the laminated film is not limited to the optical film 7 and may be an opaque resin film. Examples of the optical film include a polarizing film, a retardation film, an antireflection film, an antiglare (antiglare) film, an ultraviolet absorption film, an infrared absorption film, an optical compensation film, a brightness enhancement film, and a highly transparent film.
The laminated film of the present invention is a laminated film in which the release agent layer of the release film is bonded to the surface of the pressure-sensitive adhesive layer, and only from the release film 5 and the pressure-sensitive adhesive layer 6 as shown in FIG. The laminated film may be a laminated film including a resin film (support for the pressure-sensitive adhesive layer 6) such as the optical film 7 as shown in FIG.

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

(Release film of Example 1)
One side of a base film made of a polyester film having a thickness of 38 μm is subjected to corona treatment, and an addition reaction type silicone release agent A (manufactured by Toray Dow Corning, SRX-211, 10 weight) is applied to the corona treatment surface. So that 0.1 parts by weight of platinum catalyst SRX212 and 90 parts by weight of 50/50 mixed solvent of toluene / ethyl acetate were mixed with each other) and the thickness after drying was 0.1 μm. The coating was performed with a Mayer bar, and the mixture was heated for 1 minute in a 120 ° C. hot air circulation dryer. Thereafter, 1 part by weight of platinum catalyst SRX212 was added to 30 parts by weight of addition reaction type silicone release agent B (manufactured by Toray Dow Corning, LTC-1056L, toluene / acetic acid on the silicone release agent application surface. 70 parts by weight of 50/50 mixed solvent of ethyl and mixed) and silicone resin polymer fine particles having an average particle diameter (volume-based average particle diameter) of 2 μm (made by Momentive Performance Materials, product name: Coated with 0.0166 parts by weight of Tospearl (registered trademark) 120) with a Mayer bar so that the thickness after drying of the addition reaction type silicone release agent B becomes 0.9 μm. And it heated for 1 minute with a 120 degreeC hot-air circulation type dryer, and the release film of Example 1 was obtained.

(Release film of Example 2)
The thickness of the addition reaction type silicone release agent A after drying is 0.3 μm, the thickness of the addition reaction type silicone release agent B after drying is 0.7 μm, and the silicone resin polymer fine particles (momentive Instead of Performance Materials, product name: Tospearl (registered trademark) 120), amorphous silica with a volume-based average particle size of 2.7 μm (manufactured by Fuji Cynthia, product name: Cylicia (registered trademark) 310P) was used. Except for the above, a release film of Example 2 was obtained in the same manner as Example 1.

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

(Release film of Example 4)
The thickness of the addition reaction type silicone release agent A after drying is 0.3 μm, the thickness of the addition reaction type silicone release agent B after drying is 1.7 μm, and the silicone resin polymer fine particles (momentive Instead of Performance Materials Co., Ltd., product name: Tospearl (registered trademark) 120), a silicone resin polymer fine particle having a volume-based average particle diameter of 4.5 μm (Momentive Performance Materials Co., Ltd., product name: Tospearl ( A release film of Example 4 was obtained in the same manner as in Example 1 except that (registered trademark) 145) was used.

(Release film of Comparative Example 1)
A release film of Comparative Example 1 was prepared in the same manner as in Example 1 except that the addition reaction type silicone release agent A was not provided.

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

(Release film of Comparative Example 3)
One side of a base film made of a polyester film having a thickness of 38 μm is subjected to corona treatment, and only the addition-reactive silicone release agent B is applied to the corona-treated surface, resulting in a thickness after drying of 0.2 μm. As described above, coating was performed using a Mayer bar, and heating was performed for 1 minute using a 120 ° C. hot-air circulating drier to obtain a release film of Comparative Example 3.

(Check for blocking)
A sample in which three release films are stacked is prepared and sandwiched between two stainless plates (SUS304). The sample is allowed to stand in an environment of 23 ° C. and 50% RH for 24 hours under a load of 20 g / cm ² {0.196 N / cm ² }. Then, the release film which overlapped 3 sheets was taken out, and the blocking state was confirmed by peeling a release film one sheet at a time. No blocking was observed, and the release film was peeled off lightly, and the blocking property was good (O), and the one having resistance when the release film was peeled was determined as poor blocking property (X).

(Measurement of peel force)
A polyester adhesive tape (manufactured by Nitto Denko Corporation, trade name: polyester tape No. 31B) was bonded to the surface of the release agent layer of the release film, and aged at 70 ° C. for 20 hours under a load of 20 g / cm ² . Thereafter, the peel strength when peeled at a peeling speed of 300 mm / min and a peeling angle of 180 ° with a desktop precision universal testing machine (manufactured by Shimadzu Corporation, Autograph (registered trademark)) 50 mm).

(Measurement of residual adhesion rate)
After the test according to the above (measurement of peel force), the adhesive tape peeled off from the release film is pressure-bonded to the adherend (stainless steel plate) with a roller and left in an environment of 23 ° C. and 55% RH for 1 hour. Then, using a desktop precision universal testing machine (manufactured by Shimadzu Corp., Autograph (registered trademark)), the peeling force when peeling from the adherend at a peeling speed of 300 mm / min and a peeling angle of 180 ° is measured. The residual adhesive strength was obtained.
Separately from this, the peeling force when an unused pressure-sensitive adhesive tape was pressure-bonded to an adherend of the same material and peeled was measured in the same manner as a reference pressure-sensitive adhesive force.
The residual adhesive rate was calculated by the residual adhesive rate = (residual adhesive force) / (reference adhesive force) × 100 (%).

(Confirmation of adhesion of release agent layer)
After the test according to the above (measurement of peel force), the surface of the release agent layer of the release film was strongly rubbed with the belly of the finger three times, and then the rubbed portion was visually observed. Visually confirmed that the release agent layer had fallen off from the base film. (○), where the release agent layer was almost free. Was evaluated as (×).

(Confirmation of solvent resistance of release agent layer)
The surface of the release agent layer of the release film is rubbed once in a state where a load is applied with a weight of 200 g using a non-woven fabric impregnated with ethyl acetate (Bencot (registered trademark) M-1 manufactured by Asahi Kasei Corporation). . Then, the solvent resistance of the release agent layer of the release film was confirmed by visually observing the surface of the release agent layer of the release film. The surface of the release agent layer was confirmed by visual observation, and it was determined that the appearance did not change (O) and that the release agent layer dropped off (X).

(Measurement and confirmation test results)
Table 1 shows the results of various measurements and confirmation tests of the release films obtained in Examples 1 to 4 and Comparative Examples 1 to 3.

(Summary)
The release films of Examples 1 to 4 according to the present invention exhibited a numerical value with a very small peel force and a very high residual adhesion rate. Moreover, the release film of Examples 1-4 WHEREIN: In the confirmation test of the presence or absence of blocking, the 2nd mold release agent layer and the back surface of a release film are not raising blocking, but 2nd containing fine particles. The adhesion and solvent resistance of the release agent layer were also good.
On the other hand, since the release film of Comparative Example 1 was not provided with the first release agent layer containing no fine particles, the release agent layer containing fine particles was in contact with the base film. As a result, the solvent resistance was poor.
Further, in the release film of Comparative Example 2, the unevenness of the second release agent layer containing fine particles was small, the release film blocked, and the peeling force became heavy.
In addition, the release film of Comparative Example 3 is formed with a release agent layer formed by coating only a silicone release agent containing no fine particles with a general coating amount. Example 1 according to the present invention As a result, the release force was larger than that of the release film of ~ 4.

DESCRIPTION OF SYMBOLS 1 ... Base film, 2 ... 1st mold release agent layer, 3 ... Fine particle, 4 ... 2nd mold release agent layer, 5 ... Release film, 6 ... Adhesive layer, 7 ... Optical film, 8 ... Adhesion Attached optical film, 9 ... optical adhesive sheet, 10 ... laminate.

Claims (4)

A first release agent layer not containing fine particles and a second release agent layer containing inorganic fine particles and / or polymer fine particles as fine particles are laminated in this order on at least one surface of the base film. Release film,
The total thickness of the thickness of the first release agent layer and the thickness of the second release agent layer is 0.4 to 2.0 μm;
The tops of the fine particles protrude from the surface of the second release agent layer ,
The average protrusion height from the surface of the second release agent layer to the top of the fine particles is not less than the total thickness, and the second release agent layer is made of a silicone release agent. A release film characterized by containing.   The inorganic fine particles are at least one selected from the group of inorganic particles consisting of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, talc, and the polymer fine particles are silicone resin, acrylic resin, polyamide 2. The separation according to claim 1, which is at least one selected from the group consisting of polymer resin particles consisting of a resin, a polyester resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, and an epoxy resin. Mold film.   The release film according to claim 1 or 2, wherein the base film is a polyester film.   A laminate comprising at least one pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer laminated on at least one surface of the resin film, and the release film according to any one of claims 1 to 3, wherein the laminate is provided. A laminated film obtained by laminating the release agent layer of the release film on the surface of the pressure-sensitive adhesive layer.

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