US-12624258-B2 - Adhesive film and method for producing adhesive film

Abstract

An adhesive film or the like which is a laminate containing a substrate film containing a polycarbonate, a primer layer laminated on the surface of the substrate film, and an adhesive layer laminated on the surface of the primer layer opposite the substrate film.

Inventors

• Fumiaki KAKEYA
• Masahide Takeda
• Keisuke Tomita

Assignees

• MITSUBISHI GAS CHEMICAL COMPANY, INC.

Dates

Publication Date

20260512

Application Date

20200203

Priority Date

20190207

Claims (15)

1. 1 . An adhesive film which is a laminate comprising: a substrate film containing a polycarbonate; a primer layer laminated at least on a surface of one side of the substrate film; and an adhesive layer laminated on a surface of the primer layer on the other side from the substrate film, wherein the primer layer comprises a UV curable urethane acrylate resin, the substrate film and the primer layer are in direct contact; and the urethane acrylate resin contains at least a mixture of a hexafunctional urethane acrylate and a bifunctional acrylate, wherein the bifunctional acrylate is represented by the following structure: wherein R is hydrogen or a methyl group, or the urethane acrylate resin has an isocyanate-derived structural unit and a structural unit derived from a compound having a (meth) acryloyloxy group and a hydroxy group.
2. 2 . The adhesive film according to claim 1 , wherein the surface of the primer layer on the adhesive layer side has a wetting index of 30 (mN/m) or more in accordance with JISK6768.
3. 3 . The adhesive film according to claim 1 , wherein the adhesive layer contains at least one of a silicone adhesive agent, an acrylic adhesive agent and a urethane adhesive agent.
4. 4 . The adhesive film according to claim 1 , wherein the thickness of the primer layer is 2 μm or more but less than or equal to 10 μm.
5. 5 . The adhesive film according to claim 1 , wherein the primer layer contains any of an antistatic agent, an UV shielding agent, a near-infrared shielding agent, a light diffusion agent and metal particles.
6. 6 . The adhesive film according to claim 1 , wherein the thickness of the adhesive layer is 10 μm or more but less than or equal to 100 μm.
7. 7 . The adhesive film according to claim 1 , wherein the thickness of the substrate film is 30 um or more but less than or equal to 200 μm.
8. 8 . The adhesive film according to claim 1 , wherein the thickness of the adhesive film is 40 μm or more but less than or equal to 300 μm.
9. 9 . The adhesive film according to claim 1 , wherein the adhesive film has peel adhesion of 0.001 (N/25 mm) or more but less than or equal to 3 (N/25 mm) in a peel test where the adhesive film is laminated on a polycarbonate mirror-finished film having a thickness of 0.05 (mm) in an environment of 23° C. and relative humidity of 50%, and then peeled off in the 180° direction at 152 mm/min.
10. 10 . The adhesive film according to claim 1 , wherein the glass transition temperature of the substrate film is higher than 140° C. but lower than 160° C.
11. 11 . The adhesive film according to claim 1 , wherein the refractive index of the polycarbonate composing the substrate film is 1.55-1.65.
12. 12 . A laminate comprising a molded resin body and the adhesive film according to claim 1 attached to the molded resin body.
13. 13 . A method for fabricating the adhesive film according to claim 1 , the method comprising: applying a primer solution onto a surface of the substrate film to form the primer layer; and applying an adhesive agent to the surface of the primer layer on the other side from the substrate film to form the adhesive layer.
14. 14 . The laminate according to claim 12 , wherein the molded resin body is a polycarbonate film.
15. 15 . The laminate according to claim 12 , wherein the molded resin body is a polyimide film.

Description

TECHNICAL FIELD The present invention relates to an adhesive film comprising a substrate film that contains a polycarbonate, a primer layer and an adhesive layer, to a laminate comprising the adhesive film and to a method for fabricating the adhesive film. BACKGROUND ART Polycarbonate resins are excellent in terms of transparency, shock resistance, heat resistance, flexibility in processing, light weight and the like. Therefore, polycarbonate resins are widely used, for example, as meter covers and liquid crystal display covers in electric, electronic or office automation equipment and the like, for usage in automobiles including glass windows, sunroofs and meter covers, and as construction materials (see, for example, Patent document 1). Meanwhile, adhesive films including a polycarbonate resin layer and an adhesive layer bonding thereto that bonds tightly enough to prevent delamination thereof are known (see, for example, Patent documents 2 and 3). Since a highly adhesive layer is used for producing such an adhesive film, a process of transferring an adhesive sheet that has been molded on a separator in advance onto a polycarbonate substrate is usually employed (see, for example, Patent document 2). Hereinafter, the process of transferring an adhesive sheet onto a substrate is also referred to as a transfer process. PRIOR ART DOCUMENTS Patent Documents Patent document 1: Japanese Unexamined Patent Application Publication No. 2010-126594Patent document 2: WO2016/158827Patent document 3: Japanese Unexamined Patent Application Publication No. 2017-200975 SUMMARY OF THE INVENTION Problems to be Solved by the Invention Polycarbonate resins do not necessarily have favorable surface properties like surface hardness, solvent resistance and the like. For example, a film containing a polycarbonate is likely to cause problems such as surface whitening, swelling or the like upon contact with a solvent. Therefore, a step of protecting the surface of such a polycarbonate-containing film may be required. For example, if an adhesive agent layer is to be formed on a surface of a polycarbonate resin film by a transfer process, it requires a step of bringing the surface of the polycarbonate resin film into contact with an adhesive layer which is formed by applying and drying an adhesive agent coating material containing a solvent on a surface of a film made of a resin having satisfactory solvent resistance such as polyethylene terephthalate to transfer the adhesive layer onto the surface of the polycarbonate resin film. Such a step impairs convenient production of an adhesive film, and even with such a step, the surface of the polycarbonate resin film may be deteriorated by the solvent component remaining in the adhesive agent coating material. Thus, the objectives of the present invention are to provide an adhesive film having an adhesive layer, which can be produced by a convenient process and which can reliably protect a layer containing a polycarbonate resin, to provide a laminate including the adhesive film, and to provide a method for fabricating the adhesive film. Means for Solving the Problems In order to solve the above-described problem, the present inventors have gone through extensive research, and as a result of which found that an adhesive film can protect a surface of a substrate film containing a polycarbonate while having excellent adhesiveness when it is formed by providing a primer layer having a prescribed component onto the surface of the substrate film and then providing an adhesive layer thereon, thereby accomplishing the present invention. Thus, the present invention comprises the followings. (1) An adhesive film which is a laminate comprising: a substrate film containing a polycarbonate; a primer layer laminated at least on a surface of one side of the substrate film; and an adhesive layer laminated on a surface of the primer layer on the other side from the substrate film.(2) The adhesive film according to (1) above, wherein the primer layer comprises a urethane acrylate resin.(3) The adhesive film according to (2) above, wherein the urethane acrylate resin is a UV curable urethane acrylate having a molecular structure with cyclic skeleton.(4) The adhesive film according to (2) above, wherein the urethane acrylate resin contains at least a mixture of a hexafunctional urethane acrylate and a bifunctional acrylate.(5) The adhesive film according to (2) above, wherein the urethane acrylate resin has an isocyanate-derived structural unit and a structural unit derived from a compound having a (meth)acryloyloxy group and a hydroxy group.(6) The adhesive film according to any one of (1)-(5) above, wherein the surface of the primer layer on the adhesive layer side has a wetting index of 30 (mN/m) or more in accordance with JISK6768.(7) The adhesive film according to any one of (1)-(6) above, wherein the adhesive layer contains at least one of a silicone adhesive agent, an acrylic adhesive agent and a ureth