Patent ID: 11945984
Assignee: NITTO DENKO CORPORATION
Field: Surface technology, coating (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A reinforcing film comprising:
a film substrate; and
a pressure sensitive adhesive layer,, wherein
the film substrate is a flexible film,
the pressure sensitive adhesive layer is photocurable and before photocuring is laminated and fixed on one principal surface of the film substrate,
the pressure sensitive adhesive layer is formed of a photocurable composition comprising an acrylic base polymer and a photocurable agent,
a shear storage elastic modulus at 25° C. of the pressure sensitive adhesive layer before photocuring is 1×104 to 1.2×105 Pa,
the acrylic base polymer includes, as a monomer unit, at least one selected from the group consisting of hydroxy group-containing monomer and carboxy group-containing monomer,
the acrylic base polymer has a crosslinked structure,
a gel fraction of the photocurable composition in the pressure sensitive adhesive layer before photocuring is 60% or more,
after photocuring of the pressure sensitive adhesive layer, a shear storage elastic modulus at 25° C. of a photocured pressure sensitive adhesive layer is 1.5×105 to 2×106 Pa, and
an adhesive force between the photocured pressure sensitive adhesive layer and a polyimide film is not less than 4 times an adhesive force between the pressure sensitive adhesive layer before photocuring and the polyimide film,
the photocurable agent is polyfunctional (meth)acrylate, and
the polyfunctional (meth)acrylate includes at least one selected from the group consisting of polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate and polytetramethylene glycol di(meth)acrylate.