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JP-7855858-B2 - Release film and adhesive

JP7855858B2JP 7855858 B2JP7855858 B2JP 7855858B2JP-7855858-B2

Inventors

  • 岡田 啓生

Assignees

  • 三菱ケミカル株式会社

Dates

Publication Date
20260511
Application Date
20211222

Claims (9)

  1. It comprises a polyester film substrate, a resin layer, and a release agent layer, The resin layer is provided between the polyester film substrate and the release agent layer, The resin layer is formed from a resin composition (I) containing an aqueous resin dispersion of a polymer (X) including an olefin polymer (A), The median diameter of the aqueous resin dispersion, as measured by dynamic light scattering, is 300 nm or less. The aforementioned release agent layer is formed from a polyolefin-based release agent composition (II) , The aqueous resin dispersion of the polymer (X) is a release film in which an olefin polymer (A) and a polymer (B) containing constituent units derived from a radically polymerizable monomer having a reactive functional group are dispersed in an aqueous medium .
  2. It comprises a polyester film substrate, a resin layer, and a release agent layer, The resin layer is provided between the polyester film substrate and the release agent layer, The resin layer is formed from a resin composition (I) containing an aqueous resin dispersion of a polymer (X) including an olefin polymer (A), The median diameter of the aqueous resin dispersion, as measured by dynamic light scattering, is 300 nm or less. The aforementioned release agent layer is formed from a polyolefin-based release agent composition (II), The polyolefin-based release agent composition (II) comprises an α-olefin homopolymer or copolymer, The polyolefin-based release agent composition (II) further contains a polyolefin polyol , comprising a release film.
  3. The release film according to claim 2 , wherein the α-olefin homopolymer or copolymer is an ethylene-α-olefin copolymer or a propylene-α-olefin copolymer.
  4. The release film according to claim 2 or 3 , wherein the polyolefin-based release agent composition (II) further contains an isocyanate compound.
  5. The release film according to any one of claims 1 to 4 , wherein the olefin polymer (A) is a modified olefin polymer having a reactive group.
  6. The release film according to claim 5 , wherein the reactive group is a carboxyl group and its anhydride.
  7. The release film according to any one of claims 1 to 6 , wherein the resin composition (I) further comprises a curing agent.
  8. The release film according to claim 7 , wherein the curing agent is an oxazoline compound.
  9. An adhesive having an adhesive layer on a release agent layer of a release film according to any one of claims 1 to 8 .

Description

This invention relates to a release film and an adhesive having an adhesive layer on a release agent layer of the release film. Release films, which have a release layer on at least one side of the base film, are used in various fields such as industrial materials, optical materials, electronic component materials, and battery packaging materials. Polyethylene terephthalate (PET) film, particularly biaxially oriented PET film, is widely used as the base film for release films due to its excellent transparency, mechanical strength, heat resistance, and flexibility. Release films are widely used to protect adhesive or bonding surfaces. The most commonly used material for the release surface of release films has been silicone polymers containing siloxane units. However, because silicone-based release agents contain siloxane-based low-molecular-weight substances, when applied to precision applications such as electronic components, these substances can volatilize and oxidize in the air, causing adhesion and problems. Therefore, there was a need for a film that does not contain a siloxane source and has release properties equivalent to those of silicone-based release films. For example, hard disk drives are becoming increasingly high-performance and high-density at a remarkable pace, and this trend of increased performance and density is expected to continue in the future. Furthermore, as hard disk drives become more high-performance and denser, it has been pointed out that the deposition of the aforementioned minute silicon compounds could negatively affect the reading and writing performance of the hard disks. For example, Patent Document 1 discloses a release sheet using a non-silicone-based release agent, specifically a release sheet comprising a base material and a release agent layer provided on the base material, wherein the release agent layer is characterized by comprising an olefin-based thermoplastic elastomer having a density of at least 0.80 to 0.90 g/cm³ and a polyethylene resin. However, the release sheet disclosed in Patent Document 1 had insufficient adhesion between the polyolefin-based release agent layer and the base film, resulting in the problem that the release agent layer would detach from the adhesive layer when peeling it off. Furthermore, Patent Document 2 discloses a release film in which an antistatic layer and a release layer are sequentially provided on at least one side of a polyester film, which is a release sheet that is excellent in heat resistance, solvent resistance, adhesion between the release layer and the substrate, and antistatic properties, and in which an adhesive layer can be directly coated onto the release layer. The release film is a release film in which the release layer is a cured layer of a resin composition containing a non-reactive polyolefin, a reactive polyolefin, and a crosslinking agent, and the surface resistivity of the release layer is 1 × 10¹² Ω/□ or less. Furthermore, Patent Document 3 discloses a process film that improves the adhesion between the substrate and the polypropylene release layer, wherein at least a substrate layer, an adhesive layer, and a release layer are laminated in this order, and the adhesive layer contains an acid-modified polyolefin resin which is a copolymer of an unsaturated carboxylic acid component and an olefin component, the olefin component mainly consisting of a propylene component, and the release layer is a polyolefin resin containing 70% by mass or more of the propylene component. Japanese Patent Publication No. 2001-246697Japanese Patent Publication No. 2019-111748Japanese Patent Publication No. 2017-065115 <Release film> The release film of the present invention (hereinafter referred to as "this release film") comprises a polyester film substrate, a resin layer, and a release agent layer. Furthermore, in this release film, the resin layer is provided between the polyester film substrate and the release agent layer. In this configuration, it is preferable that the resin layer is provided on the polyester film substrate, and it is even more preferable that the release agent layer is provided on the resin layer. Furthermore, other layers may be interposed between the polyester film substrate and the resin layer, and between the resin layer and the mold release agent layer, or the layers may be directly laminated without any other layers interposed. <Polyester film base material> The polyester film of the polyester film substrate may be a single layer or a laminated structure of two or more layers. Furthermore, in the case of a laminated structure, the constituent materials of each layer may be the same or different. For example, it is possible to create a three-layer structure by using different materials for the surface layer and the intermediate layer. The polyester film in this invention may be an unoriented film (sheet) or an oriented film, but it is preferably an oriented film, and more preferably a biaxially ori