Optically clear UV and hydrolysis resistant polyester film
AssigneeToray Plastics (America), Inc.
InventorsCarlos Hinton, Nao Yokota, Hirokazu Tajima, Roberto Siu
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Abstract
Biaxially oriented polyester films including polyester polymer, a carbodiimide hydrolysis stabilizer, and a UV absorber are described. The polyester films have a carboxyl end group concentration of 5-20 equivalents per ton, and a haze value of 2% or less. The films exhibit superior transparency and possess stable light transmission characteristics. Methods of making the films and articles produced from the films are also described.
Claims31
A biaxially oriented polyester film comprising a plurality of individual layers, one of the individual layers comprising:
- polyester polymer;
- a carbodiimide hydrolysis stabilizer having a content of 0.010 wt. % or more and less than 0.1 wt. %;
- and
- a UV absorber having a content of 0.1 wt. % or more and 2 wt. % or less,
- wherein the polyester film has a carboxyl end group concentration of 5-20 equivalents per ton, and a haze value of 2% or less.
A monolayer biaxially oriented polyester film comprising:
- polyester polymer;
- a carbodiimide hydrolysis stabilizer having a content of 0.010 wt. % or more and less than 0.1 wt. %;
- and
- a UV absorber having a content of 0.1 wt. % or more and 2 wt. % or less,
- wherein the polyester film has a carboxyl end group concentration of 5-20 equivalents per ton, and a haze value of 2% or less.
A method of making a biaxially oriented polyester film comprising a plurality of individual layers, comprising:
- extruding one individual layer comprising polyester polymer, a carbodiimide hydrolysis stabilizer, and a UV absorber, to produce a polyester film;
- and
- biaxially orienting the extruded layer,
- wherein the one individual layer has a carboxyl end group concentration of 5-20 equivalents per ton, and a haze value of 2% or less, a carbodiimide hydrolysis stabilizer content of 0.010 wt. % or more and less than 0.1 wt. %, and a UV absorber content of 0.1 wt. % or more and 2 wt. % or less.
A method of making a single layer biaxially oriented polyester film, comprising:
- extruding one layer comprising polyester polymer, a carbodiimide hydrolysis stabilizer, and a UV absorber, to produce a polyester film;
- and
- biaxially orienting the extruded film,
- wherein the biaxally oriented polyester film has a carboxyl end group concentration of 5-20 equivalents per ton, and a haze value of 2% or less, and
- the carbodiimide hydrolysis stabilizer has a content of 0.010 wt. % or more and less than 0.1 wt. %, and the UV absorber has a content of 0.1 wt. % or more and 2 wt. % or less.
Dependencies are inferred from the claim text.