Manufacturing process for polyester film exhibiting low thermal shrinkage
First Claim
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1. A method of improving the shrinkage of biaxially oriented polyester film having a glass transition temperature (Tg (°
- C.)), said method comprising the steps of annealing a wound roll of said film at a temperature Ta (°
C.) above Tg where Tg<
Ta≦
Tg+100 (°
C.) for a time t after thermal equilibrium where 1 hour≦
t≦
72 hours, and then cooling, wherein the roll of film is a composite film comprising one or more coatings on one or both surfaces of a supporting polyester substrate.
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Abstract
A process in which a wound roll of biaxially oriented polyester film having a glass transition temperature (Tg (° C.)) is annealed at a temperature Ta (° C.) above Tg where Tg<Ta≦Tg+100 (° C.) for a time t after thermal equilibrium where 1 hour≦t≦72 hours and cooled, for the purpose of improving the shrinkage of said polyester film.
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20 Claims
-
1. A method of improving the shrinkage of biaxially oriented polyester film having a glass transition temperature (Tg (°
- C.)), said method comprising the steps of annealing a wound roll of said film at a temperature Ta (°
C.) above Tg where Tg<
Ta≦
Tg+100 (°
C.) for a time t after thermal equilibrium where 1 hour≦
t≦
72 hours, and then cooling, wherein the roll of film is a composite film comprising one or more coatings on one or both surfaces of a supporting polyester substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
- C.)), said method comprising the steps of annealing a wound roll of said film at a temperature Ta (°
Specification