Release film and method for manufacturing the same

Abstract

Provided are: a mold release film that enables a reduction in the amount of organic solvents which are hazardous to the human body and which have an adverse impact on the environment, and achieves both good wettability and easy release properties of a thin-film resin sheet, particularly, a thin-film ceramic green sheet; and a method for producing the mold release film. The present invention pertains to: a mold release film having a mold release layer on at least one surface of a polyester film; and a method for producing the mold release film. The mold release layer is obtained by reacting and solidifying an aqueous coating composition. The aqueous coating composition contains 10 parts by mass or less of an organic solvent with respect to a total of 100 parts by mass of the coating composition. The composition contains (a) a first silicone emulsion having at least two alkenyl groups per molecule, (b) a second silicone emulsion having at least two hydrogen groups per molecule, and (d) a surfactant. The adhesion energy of the surface of the mold release layer as calculated from the sliding angle of water is at least 6.0 mJ / m2. The tape release force of the surface of the mold release layer is at most 2000 mN / 50 mm.

Claims

[Claim 1] A release film having a polyester film and a release layer in this order, The aforementioned release layer is a layer formed by reacting and solidifying an aqueous coating composition. The aqueous coating composition contains 10 parts by mass or less of an organic solvent per 100 parts by mass of the total amount of the aqueous coating composition. The aqueous coating composition is (a) A first silicone emulsion containing at least two alkenyl groups in one molecule, (b) A second silicone emulsion containing at least two or more hydrogen groups in one molecule, and (d) comprising a surfactant, wherein the number average molecular weight of the surfactant is in the range of 200 to 2000, and / or the boiling point of the surfactant is 200°C or higher and 350°C or lower. In the aforementioned release layer, The adhesion energy of the release layer surface, calculated from the water sliding angle, is 6.0 mJ / m 2 That's all. Release films with a tape peeling force of 2000 mN / 50 mm or less, as measured by the following method; After immersing the release film in toluene for 15 minutes and then air-drying it, adhesive tape is applied to the release layer and pressed down with a 5 kg load. The resulting tape-attached release film is then held at 70°C for 20 hours, and the tape peeling force is measured by peeling it in a T-shape at a peeling speed of 0.3 m / min. [Claim 2] The aqueous coating composition (c)SiO 4 / 2 The release film according to claim 1, comprising an aqueous dispersion containing a silicone having Q units represented by the formula. [Claim 3] In the aqueous coating composition, (a) A first silicone emulsion containing at least two alkenyl groups in one molecule, having a number-average molecular weight of 1,000 or more and less than 30,000, (b) The release film according to claim 1, wherein the number average molecular weight of the second silicone emulsion containing at least two hydrogen groups in one molecule is 1,000 to 10,000. [Claim 4] The release film according to claim 1, wherein the release film is formed by applying the aqueous coating composition to a base film before crystal orientation is completed, stretching it in at least one direction, and then heat-treating it to complete the crystal orientation of the base film. [Claim 5] The release film according to claim 1, wherein the polyester film has a surface layer that is substantially free of inorganic particles, and the release layer is formed on the surface layer. [Claim 6] The release film according to claim 1, wherein the release film is a release film for manufacturing multilayer ceramic capacitors or resin sheets. [Claim 7] A method for manufacturing a release film, comprising the following steps; A coating step in which an aqueous coating composition having a liquid temperature of 0°C or higher and 40°C or lower is applied to at least one surface of a polyester film, The aqueous coating composition contains 10 parts by mass or less of an organic solvent per 100 parts by mass of the total amount of the aqueous coating composition. It contains water and a water-soluble component and / or a water-dispersible emulsion. The aqueous coating composition (A) A first silicone emulsion containing at least two alkenyl groups in one molecule, (B) A second silicone emulsion containing at least two or more hydrogen groups in one molecule, and (D) A surfactant comprising a number-average molecular weight of the surfactant in the range of 200 to 2000, and / or a boiling point of the surfactant between 200°C and 350°C. A coating step in which the surface tension of the aqueous coating composition is 40 mN / m or less; and, A heating step in which the polyester film coated with the aqueous coating composition is heated to a maximum temperature of 180°C or more and 250°C or less. [Claim 8] A method for manufacturing a release film according to claim 7, wherein the heating step comprises the following steps, and the heating step is performed after the coating step; A drying step of drying the aqueous coating composition applied to one side of the polyester film; A stretching step of stretching the polyester film in a direction perpendicular to the longitudinal direction; and, A heat-fixing step in which the polyester film is heat-treated to complete the crystal orientation. [Claim 9] A method for manufacturing a release film according to claim 7, for manufacturing a release film for manufacturing a resin sheet or a multilayer ceramic capacitor.

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