JP2019081376A - Release film having good releasability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a small peeling force, the peeling force does not easily increase even after a lapse of time in a state of being stuck to an adhesive layer, and the migration of a silicone component to the adhesive layer is small. Disclosed is a release film that does not reduce the adhesive strength of the agent layer and has excellent releasability. A first release agent layer containing no fine particles and a second release agent layer containing inorganic fine particles and/or polymer fine particles as fine particles 3 on at least one surface of a base film. 4 is a release film 5 laminated in this order, in which the first release agent layer 2 contains a silicone-based release agent, the thickness of the first release agent layer 2 and the second release agent layer 2 The total thickness including the thickness of the release agent layer 4 is 0.4 to 2.0 μm, and the apex of the fine particles 3 is projected from the surface of the second release agent layer 4. The average protruding height from the surface of the release agent layer 4 to the apex of the fine particles 3 is equal to or more than the total thickness, and the second release agent layer 4 contains a silicone-based release agent. [Selection diagram] Figure 1

Description

  The present invention relates to a release film used to protect an adhesive layer in various pressure-sensitive adhesive products and optical members having an adhesive layer. In more detail, the peeling force is small, and even when time is pasted to the pressure-sensitive adhesive layer, the peeling force is difficult to increase and the transfer of the silicone component to the pressure-sensitive adhesive layer is small. The present invention relates to a release film having excellent releasability that does not reduce the adhesive strength of the pressure-sensitive adhesive layer.

  Conventionally, release films (sometimes called release films) are used for various applications. Among them, it has a release film for molding green sheets used in the manufacture of various ceramic electronic components such as ceramic multilayer capacitors and ceramic substrates, an adhesive layer used in the manufacture of polarizing plates, optical filters, flat panel displays and the like. It is widely used for a release film for an optical member, a release film for a pressure-sensitive adhesive layer for bonding an optical member, and the like for bonding a touch panel member and optical members.

  BACKGROUND OF THE INVENTION Green sheets used in the manufacture of various ceramic electronic components such as ceramic multilayer capacitors and ceramic substrates are becoming thinner as the ceramic multilayer capacitors become smaller and larger in capacity. When peeling the green sheet from the release film, if the release force of the release film is large, the green sheet is broken. Therefore, a release film having a smaller release force than in the prior art is required.

On the other hand, in an optical member such as a polarizing plate or a retardation plate which is a member constituting a liquid crystal display, in order to protect a pressure-sensitive adhesive layer for use in bonding optical members formed on the optical member or other members. And release films are used.
The release film used for the said application is required to be able to be lightly peeled even if the size of an optical member such as a polarizing plate and the mold release film becomes large as the display becomes large. Therefore, there is a demand for a release film having a peeling force smaller than that of the prior art. In addition, with regard to the pressure-sensitive adhesive layer for the optical member for bonding the constituent members of the touch panel and the optical members, even with a thin adhesive layer such as a tablet PC, a tablet terminal or a touch panel, In order to be able to follow a level difference (for example, a level difference in frame printing used for a cover glass of a portable terminal, etc.), a pressure sensitive adhesive layer having a weak cohesive force is used. However, when using a pressure-sensitive adhesive layer with weak cohesion, the pressure-sensitive adhesive layer for an optical member is deformed if the release force of the release film is too large, so a release film having a smaller release force than before. Is required.

As described above, in the mold release film for forming a ceramic green sheet and the mold release film for an optical member having various pressure-sensitive adhesive layers, a mold release film having a smaller peeling force than in the past is required. With this background, Patent Document 1 proposes a release film using a cured silicone containing silicone having only one vinyl group in the molecule.
Moreover, in patent document 2, the precipitation prevention layer of an oligomer is provided on the single side | surface of a polyester film, and the release layer which contains addition reaction hardening type silicone of a non-solvent type | system | group is on it, Tape peeling force is 15 mN / cm or less In addition, a release film is proposed in which the transferability evaluation of the silicone component is 90% or more.
Furthermore, in Patent Document 3, release treatment is carried out using an addition reaction type silicone such as polydimethylsiloxane having no functional group, to which no light release component is added, and heat-treated for 20 hours or more in an environment of 50 to 65 ° C. A release film has been proposed which is a film, and the peel strength of the acrylic pressure-sensitive adhesive is 0.15 N / 50 mm or less and the residual adhesion rate is 90% or more.

In each of Patent Documents 1 to 3, a release film is proposed which has a small peel force and does not reduce the adhesive strength of the bonded pressure-sensitive adhesive layer. However, in the release film described in Patent Document 1, since a cured silicone containing silicone having only one vinyl group is used in the molecule, the silicone having only one vinyl group is not completely reacted. May be transferred to the pressure-sensitive adhesive layer, and the adhesion of the pressure-sensitive adhesive layer may be reduced.
Moreover, about the release film of patent document 2, that the precipitation prevention layer of the oligomer is provided differs from the conventional release film. However, since the solventless addition reaction curable silicone is used, the release performance falls under the category of the conventional release film. Furthermore, in the release film described in Patent Document 3, light release is achieved by aging the addition reaction type silicone to which no light release component is added. In this case, although the release film which does not reduce the adhesive force of the bonded adhesive layer is obtained for light peeling, it is difficult to further reduce the peeling force.

  Further, 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 wound in a roll, the back surface of the release film and the release layer become pseudo-adherent and can not be rolled up well) The solution is achieved by placing inert particles in the silicone release layer. However, since the silicone release layer becomes discontinuous due to the inert particles, when the solvent comes in contact, the solvent may permeate into the interface between the inert particles and the silicone, and the silicone may be detached. In addition, when a release film is used for surface protection of the pressure-sensitive adhesive layer in order to add the inactive particles having a particle diameter larger than the thickness of the silicone release layer, the inactive particles are on the pressure-sensitive adhesive layer side. It may adhere and reduce the adhesion of the pressure-sensitive adhesive layer.

JP, 2008-265227, A JP, 2012-136612, A JP, 2006-007689, A JP, 2013-208897, A

  The present invention has a small peeling force, and even when time passes in a state of being bonded to the pressure-sensitive adhesive layer, it is difficult to increase the peeling force and the transfer of the silicone component to the pressure-sensitive adhesive layer is small. It is an object of the present invention to provide a release film having excellent releasability that does not reduce the adhesive strength of the pressure-sensitive adhesive layer.

  As a result of intensive studies aimed at solving these problems, in order not to reduce the adhesive force of the pressure-sensitive adhesive layer, a release film using a silicone-based release agent (sometimes called a release agent) is used as an adhesive It has been found that it is necessary to reduce the silicone migration into the layer. Moreover, even when using a silicone-based mold release agent having a small amount of silicone migration to the pressure-sensitive adhesive layer, as a result of studying to reduce the peeling force, by making the thickness of the mold-release agent layer a specific thickness or more. It turned out that the peeling force can be reduced. However, when the thickness of the release agent layer is increased, the release film is wound into a roll, and blocking occurs when the release agent layer is joined to the back surface of the release film, and the release is performed. It was found that the film could not be rolled up in a clean manner. The base film used for the release film contains lubricant particles in the base film so that blocking does not occur even if the base film is wound into a roll shape in the production process. I am forming a film. For this reason, on the back surface 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 of the base film surface is released. The fact that the agent layer is filled is considered to be the cause of the blocking.

  In addition, the present invention has been completed by intensively studying a method for achieving both the releasability and the 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 using a release agent in which the migration of the silicone component to the pressure-sensitive adhesive layer is small. Moreover, in order to prevent blocking between the release agent layer and the back surface of the release film, the present invention forms peelability and blocking resistance by forming an uneven shape with an appropriate surface roughness in the release agent layer. The technical idea is to make it compatible. As a means for forming an appropriate uneven shape in the release agent layer, inorganic particles and / or polymer particles are contained as fine particles in the release agent layer. However, just by providing the release agent layer containing the fine particles in the base film, when the solvent comes in contact, 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, the substrate film is not simply provided with a release agent layer containing fine particles so that the solvent does not penetrate to the interface between the release agent layer and the base film, and no fine particles are contained therebetween. By providing the release agent layer, it was found that the solvent resistance was also improved, and that both the releasability and the blocking resistance were compatible, and the present invention was completed.

  In the present invention, on at least one surface of a substrate film, a first release agent layer containing no fine particles, and a second release agent layer containing fine inorganic particles and / or fine polymer particles as fine particles are It is a release film laminated | stacked in this order, Comprising: The total thickness which united the thickness of a said 1st release agent layer, and the thickness of a said 2nd release agent layer is 0.4-2. The top of the fine particles protrudes 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 top of the fine particles is 0 μm. It is a total thickness or more, and the second release agent layer contains a silicone-based release agent.

  The inorganic fine particles are at least one selected from an inorganic particle group consisting of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, and 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 polymeric resin particle group which consists of base resin, 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.

  Further, the present invention comprises a laminate having a surface of one or more pressure-sensitive adhesive layers in which an adhesive layer is laminated on at least one side of a resin film, and the above-described release film, There is provided a laminated film formed by laminating the release agent layer of the above-mentioned release film on the surface of the layer.

  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 is pasted to the pressure-sensitive adhesive layer, the peel force does not easily increase, and migration of the silicone component to the pressure-sensitive adhesive layer is small. The release film excellent in peelability which does not reduce the adhesive force of the bonded adhesive layer can be provided.

It is sectional drawing which shows typically an example of the release film of this invention. It is sectional drawing which shows typically the 1st example of a laminated film of this invention. It is sectional drawing which shows typically the 2nd example of a laminated 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 the release film of the present invention, wherein a first release agent layer 2 containing no fine particles, inorganic fine particles and / or 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 application, but a polyester resin film, a polyamide resin film, a polyimide resin film, a polyolefin resin film, a polyvinyl chloride resin film And polystyrene resin films, acrylic resin films, acetate resin films, polyphenylene sulfide resin films and the like.
Among them, polyester resin films are preferable from the viewpoints of characteristics such as optical characteristics and heat resistance, price and appearance quality. 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 in terms of cost and optical properties. From the viewpoint of optical properties, polyethylene terephthalate for uniaxially stretched or biaxially stretched products for optics is preferred.
In addition, if necessary, the surface of the base film 1 may be subjected to an easy adhesion treatment such as surface modification by plasma discharge or corona discharge, application of an anchor coating agent, or the like.

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

In the release film of the present invention, the first release agent layer 2 containing no fine particles and the second release containing fine particles 3 consisting of inorganic fine particles and / or polymer fine particles on at least one surface of the base film. The mold agent 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 mold release agent (when peeling the mold release film from the pressure sensitive adhesive layer etc., the film at the mold release agent layer is slightly deformed as an elastomer by the stress at the time of peeling, and the pressure sensitive adhesive layer It is a layer that also has a function to concentrate stress at the interface of the release agent layer.

  As a mold release agent used for the 1st mold release agent layer 2, a silicone type mold release agent is mentioned. Examples of the silicone-based release agent include known silicone-based release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and radical polymerization type. Commercially available products as addition reaction type silicone-based release agents include, 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. product), 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), and the like. As a product marketed as a condensation reaction type, SRX-290, SYLOFF-23 (made by Toray Dow Corning Co., Ltd. product), YSR-3022 (made by Momentive Performance Materials Co., Ltd.) etc. are mentioned, for example. Products marketed as cationic polymerization type include, for example, TPR-6501, TPR-6502, TPR-6500, UV9300, VU9315, UV9430 (manufactured by Momentive Performance Materials), X62-7622, X-62. 7660 and X-62-7655 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like. As a product marketed as a radical polymerization type | mold, KF-2005, X62-7205 (Shin-Etsu Chemical Co., Ltd. product) etc. are mentioned, for example. As a release agent with less migration of the silicone component to the adhesive layer, a silicone release agent containing no light release additive component (silicone having no organic functional group involved in the addition reaction, such as polydimethylsiloxane etc.) Can be mentioned.

The silicone-based release agent may be used alone or in combination of two or more. Further, components other than the silicone-based release agent such as a silane coupling agent, an antistatic agent, and a wettability improver may be added, and it may be determined in consideration of releasability, coatability, curability, and the like. The application of the release agent may be performed by a known method, and is not particularly limited, but may be the Mayer bar method, the gravure method, the reverse roll method, the air knife method, the multistage roll method and the like. The curing method of the silicone-based release agent includes methods such as heat curing, ultraviolet curing, electron beam curing, combined use of heating and ultraviolet irradiation, etc., but a suitable method is selected according to the type of silicone-based release agent. It should just be adopted. The thickness of the first release agent layer 2 is not particularly limited, but is preferably 0.1 μm or more in order to secure sufficient solvent resistance.
Total of the sum of the thickness of the first release agent layer 2 not containing fine particles and the thickness of the second release agent layer 4 containing fine particles 3 (average thickness of the portion without fine particles 3) The thickness (total thickness of the release agent layer) may be adjusted in the 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. . Even if the thickness of the release agent layer containing the silicone-based release agent is increased, fine particles 3 do not cause blocking when the release agent layer is brought into contact with the back surface of the release film. It is used to form an uneven shape on the surface of the release agent layer 4.
Examples of the inorganic fine particles and / or polymer fine particles which are the fine particles 3 for blocking prevention include inorganic fine particles which are fine particles of an inorganic compound, and polymer fine particles which 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. Also, one kind of polymer particles selected from the group of polymer resin particles consisting of silicone resin, acrylic resin, polyamide resin, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, epoxy resin It is preferable that it is more than.
The shape of the fine particles 3 is not particularly limited, and may be spherical, rod-like, scaly, hemispherical, convex lens-like, mushroom-like, indeterminate, etc. It is more preferable because the performance is enhanced.
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 apex of the fine particles 3 protruding from the surface of the second release agent layer 4 (fine particles 3 The fine particles having a volume-based average particle diameter may be selected such that the protrusion height of (1) is equal to or greater than the total thickness of the first release agent layer 2 and the second release agent layer 4. The top of the fine particle 3 may be a point farthest from the surface of the second release agent layer 4, and it does not matter whether the top is sharp or rounded.

As a mold release agent which forms the 2nd mold release agent layer 4 which functions also as a binder resin of the microparticles | fine-particles 3, a silicone type mold release agent is mentioned. Examples of the silicone-based release agent include known silicone-based release agents such as addition reaction type, condensation reaction type, cationic polymerization type, and radical polymerization type.
The silicone-based release agent may be used alone or in combination of two or more. Further, components other than the silicone-based release agent such as a silane coupling agent, an antistatic agent, and a wettability improver may be added, and it may be determined in consideration of releasability, coatability, curability, and the like. The silicone-based release agent that forms the second release agent layer 4 may be the same silicone-based 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-based 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 (average thickness of the portion without the fine particles 3). The release agent of the second release agent layer 4 may or may not be thinly attached to the upper surface of the fine particle 3. 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 method of mixing and dispersing the fine particles 3 in the release agent of the second release agent layer 4 may be carried out by a known method in accordance with the types of the release agent and the fine particles. If it is a system in which fine particles are easily dispersed in the release agent, it may be stirred and mixed with a manual device such as a spatula. Even in a combination in which fine particles are difficult to disperse in the release agent, or in a system in which the fine particles are easily dispersed, even when the release agent and the fine particles are contained in a large amount, dispersion may be carried out using a disperser such as a homogenizer or homomixer. good. In addition to the fine particles and the release agent, if necessary, a colorant, an antistatic agent, a leveling agent, an adhesion improver, and the like may be added.

  In the method of forming the second release agent layer 4 containing the fine particles 3, the release agent containing the fine particles 3 is coated on the first release agent layer 2 formed on the base film 1. It should be provided. The coating method is not particularly limited, and may be selected from known coating methods in accordance with the viscosity and the amount of the release agent containing the fine particles 3. As an example, a mayer bar method, a gravure method, a reverse roll method, an air knife method, a multistage roll method, etc. may be mentioned.

  The curing or solidification of the second release agent layer 4 containing the fine particles 3 may be performed according to the type of release agent. For example, removal of the solvent or water by heat drying, curing of the release agent layer by ultraviolet irradiation, electron beam irradiation or the like may be performed.

  The thickness of the second release agent layer 4 is not particularly limited, but in order to sufficiently secure the function of the particles 3 as a binder resin, it is 25% or more of the volume-based average particle diameter of the particles 3 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 be large. The upper limit of the total thickness of the first release agent layer 2 and the second release agent layer 4 is not particularly limited. However, the upper limit of the total thickness of the first release agent layer 2 is not particularly limited. In the case where the total thickness of the thickness and the thickness of the second release agent layer 4 is increased, the cost is increased, and the volume-based average particle diameter of the fine particles 3 is increased to release the release film. It is preferable to reduce the thickness to about 2 μm because there is a problem that the appearance of the film becomes whitish.

  When the mold release film 5 of the present invention is used for mold release sheets for forming green sheets used in the manufacture of various ceramic electronic parts, the green sheets are coated and dried with a slurry in which ceramic particles are dispersed in an organic solvent. It is formed by In such a release film 5 used for the application which protects a green sheet, solvent resistance is required. 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 from the gap between the releasing agent of the second releasing agent layer 4 and the fine particles 3 to the interface between the second releasing agent layer 4 and the first releasing agent layer 2. Since the solvent does not reach 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. It is. In addition, the release film 5 of the present invention is not limited to the green sheet, and is suitably used for protecting the surface of a coating obtained by dispersing various powders, such as a conductor paste and an insulator paste, and a coating 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. The pressure-sensitive adhesive optical film 8 of FIG. 2 is used for protecting the pressure-sensitive adhesive layer 6 laminated on the optical film 7 of the release film 5 of the present invention. The optical film 7 is bonded to the release film 5 of the present invention of FIG. 1 via the pressure-sensitive adhesive layer 6. In the method of manufacturing such a tacky optical film 8, after the solvent-type adhesive is applied to the release film 5 and dried, the optical film 7 may be bonded. The release film 5 used for the purpose of protecting the pressure-sensitive adhesive layer 6 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 from the gap between the releasing agent of the second releasing agent layer 4 and the fine particles 3 to the interface between the second releasing agent layer 4 and the first releasing agent layer 2. Since the solvent does not reach 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. 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 pressure-sensitive adhesive layer 6 may be provided on both sides of the optical film 7, and the release film 5 may be bonded to each pressure-sensitive adhesive layer 6. As another manufacturing method, the release film 5 may be bonded to the laminate 10 in which the pressure-sensitive adhesive layer 6 is provided on one side of the optical film 7. Alternatively, after applying the solventless pressure-sensitive adhesive, the pressure-sensitive adhesive layer 6 can be cured between the release film 5 and the optical film 7 by light, heat, or the like. 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 adhesion between the optical film 7 and the pressure-sensitive adhesive layer 6 is larger than the peeling force at the time of peeling the release film 5 from the pressure-sensitive adhesive layer 6.

  FIG. 3 is a cross-sectional view schematically showing a second embodiment of the laminated film of the present invention. The optical pressure-sensitive adhesive sheet 9 of FIG. 3 is one in which the release film 5 of the present invention is attached to the pressure-sensitive adhesive layer 6 used for bonding the touch panel member and the optical member 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 the method of manufacturing such an optical adhesive sheet 9, it is general to apply a solvent-type adhesive to one of the release films 5 and dry it, and then to bond the other release film 5. The release film 5 used for the purpose of protecting the pressure-sensitive adhesive layer 6 is required to have solvent resistance. Since the release film 5 of the present invention has good solvent resistance, it can be suitably used for 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-water-based (solvent-based) or non-solvent type. The pressure-sensitive adhesive may be any of acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives and the like. Acrylic pressure-sensitive adhesives are preferable 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 but may be an opaque resin film. The optical film may, for example, be a polarizing film, a retardation film, an antireflective film, an antiglare film, an ultraviolet absorbing film, an infrared absorbing film, an optical compensation film, a brightness enhancement film, a highly transparent film or the like.
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 as shown in FIG. 3, only from the release film 5 and the pressure-sensitive adhesive layer 6 The laminated film may be a laminated film including a resin film (support of the pressure-sensitive adhesive layer 6) such as the optical film 7 as shown in FIG.

  Hereinafter, the present invention will be specifically described by way of examples.

(Release film of Example 1)
A corona treatment is applied to one side of a substrate film made of a polyester film having a thickness of 38 μm, and the corona-treated surface is 10% by weight of an addition reaction type silicone-based mold release agent A (Toray Dow Corning, SRX-211) 0.1 parts by weight of a platinum catalyst SRX 212 and 90 parts by weight of a 50/50 mixed solvent of toluene / ethyl acetate are mixed and mixed so that the thickness after drying becomes 0.1 μm, It coated with a mayer bar and heated for 1 minute with a 120 degreeC hot-air circulation type drier. After that, 1 part by weight of SRX 212 as a platinum catalyst with respect to 30 parts by weight of an addition reaction type silicone-based mold release agent B (Toray Dow Corning, LTC-1056L) on the silicone type release agent coated surface, toluene / acetic acid 70 parts by weight of a 50/50 mixed solvent of ethyl was mixed and mixed, and a silicone resin polymer fine particle (Momentive Performance Materials Co., Ltd., product name: average particle diameter (volume based average particle diameter) is 2 μm. A mixture of 0.0166 parts by weight of Tospearl (registered trademark) 120) is coated with a Mayer bar so that the thickness after drying of the addition reaction type silicone mold release agent B becomes 0.9 μm. The resultant was heated for 1 minute in a hot air circulating drier at 120 ° C. to obtain a release film of Example 1.

(Release film of Example 2)
The dry thickness of the addition reaction type silicone mold release agent A is 0.3 μm, and the dry thickness of the addition reaction silicone type release agent B is 0.7 μm. Amorphous silica (Fuji Shinsia Co., Ltd., product name: Siricia (registered trademark) 310P) made of volume average particle diameter 2.7 μm instead of Performance Materials, Inc., product name: Tospearl (registered trademark) 120) A release film of Example 2 was obtained in the same manner as Example 1 except for the difference.

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

(Release film of Example 4)
The dry thickness of the addition reaction type silicone mold release agent A was 0.3 μm, and the dry thickness of the addition reaction silicone type release agent B was 1.7 μm. Silicone-based resin polymer fine particles with a volume-based average particle diameter of 4.5 μm (productive performance materials, product name: Tospearl (product name: Tospearl (product name): product made by Performance Materials, product name: Tospearl (registered trademark) 120) A release film of Example 4 was obtained in the same manner as in Example 1 except that it was changed to registered trademark (145).

(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.

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

(Release film of Comparative Example 3)
A corona treatment is given to one side of a substrate film consisting of a polyester film having a thickness of 38 μm, and only the addition reaction type silicone-based mold release agent B is dried on the corona treated surface to a thickness of 0.2 μm after drying. Thus, it was coated with a Mayer bar and heated for 1 minute in a hot air circulating dryer at 120 ° C. to obtain a release film of Comparative Example 3.

(Confirmation of presence or absence of blocking)
A sample in which three release films are stacked is prepared and sandwiched between two stainless steel plates (SUS304). The sample is left 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 }. After that, the three laminated release films were taken out, and the blocking condition was confirmed by manually peeling the release films one by one. There was no blocking, and the release film was lightly peeled off was regarded as good in blocking properties (、), and the release film in which resistance was observed at the release was regarded as blocking failure (×).

(Measurement of peeling force)
A polyester adhesive tape (manufactured by Nitto Denko Corporation, trade name: polyester tape No. 31B) was attached 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 After that, the peel strength when peeled off at a peeling speed of 300 mm / min and a peeling angle of 180 ° with a table-type precision universal testing machine (Autograph (registered trademark) manufactured by Shimadzu Corporation) It measured as 50 mm.

(Measurement of residual adhesion rate)
The adhesive tape peeled off from the mold release film after the above test (measurement of peeling force) is crimped to the adherend (stainless steel plate) with a roller, and left for 1 hour in an environment of 23 ° C. and 55% RH. Then, using a table-type precision universal testing machine (Autograph (registered trademark) manufactured by Shimadzu Corporation), measure the peeling force when peeling from the adherend at a peeling speed of 300 mm / min and a peeling angle of 180 °. And the residual adhesive strength.
Apart from this, the peeling force when pressing and peeling an unused adhesive tape onto an adherend of the same material was similarly measured and used as the standard adhesive force.
The residual adhesion rate was calculated by residual adhesion rate = (residual adhesive force) / (reference adhesive force) × 100 (%).

(Confirmation of adhesion of release agent layer)
The surface of the release agent layer of the release film after the test according to the above (measurement of peeling force) was strongly rubbed three times with the inside of a finger, and the rubbed portion was visually observed. The presence or absence of the release agent layer was visually confirmed from the base film, and the release agent layer was found to be hardly dropped off (○), and the release agent layer was significantly dropped off Was evaluated as (x).

(Confirmation of solvent resistance of release agent layer)
Using a non-woven fabric impregnated with ethyl acetate (Bencott (registered trademark) M-1 manufactured by Asahi Kasei Corp.), the surface of the release agent layer of the release film is rubbed once with 200 g of weight under load. . Thereafter, 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 visually confirmed, and those having no change in appearance were judged as (○), and those from which the release agent layer dropped were judged as (×).

(Result of measurement, confirmation test)
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 showed very small peel force and very high residual adhesion rate. In addition, the release films of Examples 1 to 4 do not cause blocking between the second release agent layer and the back surface of the release film in the confirmation test for the presence or absence of blocking, and contain the fine particles. The adhesion of the release agent layer and the solvent resistance were also good.
On the other hand, the release film of Comparative Example 1 has a structure in which the release agent layer containing the fine particles is in contact with the base film because the first release agent layer containing no fine particles is not provided. And 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 was also heavy.
Further, the release film of Comparative Example 3 is coated with a silicone type release agent containing no fine particles at a general coating amount to form a release agent layer, and Example 1 according to the present invention The result is that the peeling force is larger than that of the release film of -4.

DESCRIPTION OF SYMBOLS 1 ... Base film, 2 ... 1st release agent layer, 3 ... microparticles | fine-particles, 4 ... 2nd release agent layer, 5 ... Release film, 6 ... Adhesive layer, 7 ... Optical film, 8 ... Adhesion With optical film, 9 ... optical adhesive sheet, 10 ... laminate.

Claims (3)

On at least one surface of the base film, a first release agent layer not containing fine particles and a second release agent layer containing fine inorganic particles and / or fine polymer particles as fine particles are laminated in this order Release film, and
The inorganic fine particles are at least one selected from an inorganic particle group consisting of silica, calcium carbonate, calcium phosphate, barium sulfate, kaolin, glass powder, and talc, and the polymer fine particles are silicone resin, acrylic resin, polyamide At least one selected from a group of polymer resin particles comprising a polyester resin, a polyester resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, and an epoxy resin,
The first release agent layer contains a silicone-based release agent,
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 top of the fine particles protrudes 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 a silicone-based release agent. A release film characterized by including.   The release film according to claim 1, wherein the base film is a polyester film.   A laminate having a surface of one or more pressure-sensitive adhesive layers in which a pressure-sensitive adhesive layer is laminated on at least one surface of a resin film, and the release film according to claim 1 or 2 The laminated film formed by bonding the mold release agent layer of the said mold release film together on the surface of a layer.

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