Surface protective film
AssigneesBando Chemical Industries, Ltd., Wacom Co., Ltd.
InventorsYutaka Kamada, Arata Tani, Toshihiko Horie, Soh Kato
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Abstract
The present invention addresses the problem of providing a surface protective film which is resistant to discoloration, expansion and the like caused by the penetration of a plasticizer. A surface protective film having, on the outermost surface thereof, a protective layer made of polycarbonate type polyurethane is provided as the solution of the problem.
Claims7
A surface protective film comprising:
- at least three layers including a protective layer, a transparent substrate film, and an adhesive layer laminated in that order,
- wherein the protective layer is formed of a polycarbonate-based polyurethane,
- the protective layer is on an outermost surface of the surface protective film,
- the protective layer contains a silicone-based additive, the silicone-based additive is any one selected from the group consisting of a polyether-modified polydimethylsiloxane, a polyaralkyl-modified polydimethylsiloxane, and a long chain alkyl-modified polydimethylsiloxane,
- a thickness of the protective layer is 50 μm or more and 300 μm or less,
- the polycarbonate-based polyurethane does not have an acrylic framework or a methacrylic framework,
- the transparent substrate film is a single substrate,
- a haze value of the surface protective film is 0.1% or more and 40% or less, and
- the polycarbonate-based polyurethane is a thermosetting polyurethane.
A method of producing a surface protective film having at least three layers including a protective layer, a transparent substrate film, and an adhesive layer laminated in that order, the protective layer being formed of a polycarbonate-based polyurethane, the protective layer being on an outermost surface of the surface protective film, comprising:
- pouring a material composition containing a polycarbonate-based polyol, an isocyanate, an alcohol-based curing agent, and a catalyst into a gap between first and second gap maintaining members that are conveyed by a pair of rollers that are disposed apart from each other;
- and
- thermally curing the material composition that is held between the first and second gap maintaining members to form the protective layer, wherein the polycarbonate-based polyurethane does not have an acrylic framework or a methacrylic framework, the protective layer contains a silicone-based additive, the silicone-based additive is any one selected from the group consisting of a polyether-modified polydimethylsiloxane, a polyaralkyl-modified polydimethylsiloxane, and a long chain alkyl-modified polydimethylsiloxane, a thickness of the protective layer is 50 μm or more and 300 μm or less, the transparent substrate film is a single substrate, and a haze value of the surface protective film is 0.1% or more and 40% or less.
Dependencies are inferred from the claim text.