Release film

Abstract

To provide a heavy release film that can suppress heavy peeling over time even after applying an adhesive layer, and is suitable for various optical applications such as the case that requires releasability in a heavy peeling area and the situation that dislikes heavy peeling over time after adhesive bonding.SOLUTION: There is provided a release film in which a release layer is laminated on at least one side of a polyester film, in which the release layer is a cured product of a release layer composition containing a curable silicone resin (A) (excluding MQ resin (B)), MQ resin (B), and a catalyst, where the curable silicone resin satisfies the following (1) and (2) simultaneously: (1) it contains polyorganosiloxane containing an alkenyl group having 6 to 10 carbon atoms in a molecule; and (2) 2.5≤SiH group / alkenyl group (molar ratio)≤9.SELECTED DRAWING: None

Claims

1. A release film comprising a polyester film with a release layer laminated on at least one side, wherein the release layer is a cured product of a release layer composition containing a curable silicone resin (A) (excluding MQ resin (B)), MQ resin (B), and a catalyst that simultaneously satisfies (1) and (2) below, and the MQ resin (B) does not contain either an alkenyl group or an SiH group. (1) A polyorganosiloxane containing an alkenyl group having 6 to 10 carbon atoms in the molecule. (2) 3.0 ≤ SiH group / alkenyl group (molar ratio) ≤ 5.0

2. The release film according to claim 1, wherein the rate of repeated peeling of the release layer and the acrylic adhesive over time, as evaluated by the following method, is 60% or less. <Evaluation Method> Apply an acrylic adhesive, consisting of the following adhesive composition, to the release layer surface of the release film so that the application amount (before drying) is 2 ml, and then heat treat at 150°C for 3 minutes. The heat-treated adhesive surface is bonded to an untreated biaxially oriented polyethylene terephthalate film (100 μm thick) using a rubber roller with a load of 2 kg to produce an adhesive release film. The peeling force is achieved by 180° peeling under a tensile speed of 300 mm / min. Next, the peel strength of the bonded adhesive release film after being left at room temperature for one day is defined as (F1), and the peel strength after being placed in an 80°C hot air circulating oven for four days is defined as (F2). The rate of heavy peeling over time is then calculated using the following formula. Time-dependent peeling rate % = (F2 - F1) / F1 × 100 <Adhesive composition> Main ingredient: AT352 (manufactured by Saiden Chemical Co., Ltd.) 100 parts by mass Hardener: AL (manufactured by Saiden Chemical Co., Ltd.) 0.25 parts by mass Additive: X-301-375K (manufactured by Saiden Chemical Co., Ltd.) 0.25 parts by mass Additive: X-301-352S (manufactured by Saiden Chemical Co., Ltd.) 0.4 parts by mass 40 parts by mass of toluene

3. The release film according to claim 1 or 2, comprising a cured resin layer between a polyester film and a release layer, the resin layer containing a compound made of thiophene or a thiophene derivative and a binder.

4. A release film according to any one of claims 1 to 3, wherein the film surface opposite to the surface on which the release layer is provided is provided with a cured resin layer containing a compound made of thiophene or a thiophene derivative and a binder.

5. A film laminate in which another release film is bonded to the release surface of a release film according to any one of claims 1 to 4 above, via an adhesive layer.

6. The film laminate according to claim 5, wherein the adhesive layer is an optically transparent adhesive sheet (OCA).

7. A method for using a film laminate according to claim 5 or 6, wherein after peeling off the other release film, the exposed adhesive layer surface is bonded to the optical member.

8. The method for using the film laminate according to claim 7, wherein the optical element is a polarizing plate.

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