Solution casting process for producing polymer film
AssigneeFuji Photo Film Co., Ltd.
InventorsToshinao Arai, Hidekazu Yamazaki, Hitoshi Ikeda
Life of this patent
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Abstract
A solution casting process for producing cellulose triacetate (TAC) film is provided. Bead of dope, which includes cellulose triacetate and solvent, is cast on to a rotating supporting drum, to form self-supporting cast film. The self-supporting cast film is stripped from the supporting drum. The self-supporting cast film is dried while the self-supporting cast film being stripped is fed by feed rollers, to form the cellulose triacetate film. A surface temperature of the feed rollers is set equal to or lower than 0° C. The self-supporting cast film upon being stripped has modulus of longitudinal elasticity equal to or more than 450,000 Pa.
Claims15
A solution casting process comprising steps of:
- casting dope on to a support by use of at least one solution casting die, to form self-supporting cast film, said dope including polymer and solvent;
- stripping said self-supporting cast film from said support;
- drying said self-supporting cast film by use of a drier while said self-supporting cast film being stripped is fed by at least one feed roller, to form polymer film;
- wherein a surface temperature of said feed roller is set equal to or lower than 0° C., whereby said self-supporting cast film upon being stripped has modulus of longitudinal elasticity equal to or more than 450,000 Pa.
A solution casting process comprising steps of:
- casting dope on to a support, to form self-supporting cast film, said dope including polymer and solvent;
- stripping said self-supporting cast film from said support;
- drying said self-supporting cast film while said self-supporting cast film being stripped is fed, to form polymer film;
- while said self-supporting cast film is fed, blowing gas on said self-supporting cast film, said gas having a temperature equal to or lower than 0° C., whereby said self-supporting cast film upon being stripped has modulus of longitudinal elasticity equal to or more than 450,000 Pa.
A solution casting process comprising steps of:
- casting dope on to a support, to form self-supporting cast film, said dope including polymer and solvent;
- stripping said self-supporting cast film from said support;
- drying said self-supporting cast film while said self-supporting cast film being stripped is fed, to form polymer film;
- while said self-supporting cast film is fed, pressing a first surface of said self-supporting cast film by use of a rotatable decurling roller, to prevent occurrence of a curl on said self-supporting cast film, said first surface having been separated from said support;
- wherein a surface temperature of said decurling roller is set equal to or lower than 0° C., so as to determine a drying speed difference (dW/dt) between said first surface and a second surface of said self-supporting cast film equal to or less than 0.05 kg solvent per kg of solid per second, said second surface being reverse to said first surface.
A solution casting process comprising steps of:
- casting first to Nth dopes on to a support according to at least one of multi-manifold solution casting and successive solution casting, to form self-supporting cast film in a multi-layer state, each of said first to Nth dopes including polymer and solvent;
- stripping said self-supporting cast film from said support;
- drying said self-supporting cast film while said self-supporting cast film being stripped is fed, to form polymer film;
- wherein said first dope is cast in a range extending to have two lateral edge portions of said self-supporting cast film, said second to Nth dopes are cast in a range of a middle portion between said two lateral edge portions, said first dope having higher density than said second to Nth dopes, to provide said two lateral edge portions with modulus of longitudinal elasticity equal to or more than 450,000 Pa.
A solution casting process comprising steps of:
- casting dope on to a support, to form self-supporting cast film, said dope including polymer and solvent;
- stripping said self-supporting cast film from said support;
- drying said self-supporting cast film while said self-supporting cast film being stripped is fed, to form polymer film;
- wherein said self-supporting cast film upon being stripped is so formed that a ratio A/B of thickness A to thickness B is in a range of 1–5, where said thickness A is thickness of two lateral edge portions of said self-supporting cast film, and said thickness B is thickness of a middle portion of said self-supporting cast film disposed between said two lateral edge portions.
Dependencies are inferred from the claim text.