JP-7856160-B2 - Release film

Inventors

• 矢野 真司

Assignees

• 東洋紡株式会社

Dates

Publication Date

20260511

Application Date

20230829

Priority Date

20220906

Claims (3)

1. A release film having a base film and a release layer, In a micro-slurry jet erosion test, the aforementioned release layer exhibited an erosion rate of 0.003 μm/g or higher when a slurry of polygonal alumina particles with an average particle size (D 50 ) of 0.3 μm dispersed in water was projected onto the polymethyl methacrylate resin at a projection force that resulted in an erosion rate of 0.019 μm/g. The release layer is formed by reacting and solidifying a reaction-curable composition containing a silicone-based compound. The reaction-curable composition includes an alkenyl group-containing silicone having Q units represented by SiO₄ /2 . Release film.
2. The release film according to claim 1, wherein the base film is a polyester film.
3. The release film according to claim 1 or 2, wherein the release film is a release film for multilayer ceramic capacitors or a release film for resin sheets.

Description

The present invention relates to a release film having a base film and a release layer, and more particularly to a release film useful as a film for various processes. Conventionally, release films based on polyester films and the like have high heat resistance and mechanical properties, and are used as process films for manufacturing adhesive sheets, cover films, and resin sheets such as ceramic slurries and polymer electrolyte membranes. Furthermore, many release layers formed from silicone-containing coating compositions have been proposed for release films due to their good heat resistance and release properties (for example, Patent Documents 1-4). Patent documents 1 and 2 propose a release film in which a release layer is formed by a coating composition containing a polysiloxane having an unsaturated group, a polysiloxane having a Si-H group, a platinum group metal catalyst, and an organic solvent. Furthermore, as a technique suitable for coating during the stretching and film formation of a base film (hereinafter referred to as "in-line coating"), Patent Document 3 proposes a release film in which a release layer is formed using an aqueous coating composition containing an alkenyl group-containing silicone and a Si-H group-containing silicone. Also, as an example, a release film is disclosed in which a release layer is formed using an alkenyl group-containing silicone with a number average molecular weight of 25,000 and a Si-H group-containing silicone with a number average molecular weight of 4,500. Furthermore, Patent Document 4 proposes a release film in which a release layer is formed using an aqueous coating composition containing an alkenyl group-containing silicone having Q units represented by SiO₄ /2 and an Si-H group-containing silicone, for the purpose of achieving both easy release and good wettability. In addition, as an example, a release film is disclosed in which a release layer is formed using an alkenyl group-containing silicone with a number average molecular weight of 25,000 having Q units and an Si-H group-containing silicone with a number average molecular weight of 4,500. Thus, conventionally, when forming a release layer, relatively high molecular weight polysiloxanes containing unsaturated groups were generally used to facilitate the formation of the polydimethylsiloxane helical structure on the coating surface. This was also the case when using organic solvent-based coating compositions (for example, Patent Documents 1-2). On the other hand, there are attempts to improve the release properties of release films by measuring the hardness of the release layer and adjusting its hardness. For example, Patent Document 5 describes an attempt to evaluate the release characteristics of a release film by creating the release layer of the release film separately as a solid body, measuring its rubber hardness, and so on. However, with this method, the solid body of the release layer, which has undergone a different formation history than the actual manufacturing process of the release film, is evaluated, resulting in an evaluation of release characteristics that differs from those of the actual release film. Furthermore, as a technique for directly measuring the hardness of the release layer, Patent Document 6 proposes a release film for manufacturing ceramic green sheets, which uses a polyester film as a base material, has a release coating layer on one surface, and whose film elastic modulus measured from the surface by a nanoindentation test on the release coating layer is 2.0 GPa or higher, and has a smooth coating layer containing particles on the other surface of the base material. In this case, a nanoindentation test is performed using a microhardness evaluation device with a maximum indentation depth of 50 nm, and the film elastic modulus of the release coating layer is measured. Japanese Patent Publication No. 2003-292894Japanese Patent Publication No. 2003-292895Patent No. 6077327Japanese Patent Publication No. 2021-11081Japanese Patent Publication No. 2012-6213International Publication WO2019/065214 This photograph shows an example where the half-cut evaluation is "○".This photograph shows an example of a case where the half-cutability evaluation is "△".This photograph shows an example of a case where the half-cut evaluation is "×". The release film of the present invention is a release film having a base film (hereinafter sometimes referred to as "base") and a release layer, wherein the release layer is characterized in that, in a micro-slurry jet erosion test, when a slurry of polygonal alumina particles with an average particle size (D 50 ) of 0.3 μm dispersed in water is projected at a projection force that results in an erosion rate of 0.019 μm/g for polymethyl methacrylate resin, the erosion rate is 0.003 μm/g or more. First, the micro-slurry jet erosion test will be explained. [Micro-slurry jet erosion test] The principle of this test is to measure the shape of abrasion