Polyester films containing glass spheres and calcined china clay
AssigneesImperial Chemical Industries PLC, ICI Americas Inc.
InventorsJunaid A. Siddiqui, Paul D. A. Mills
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Abstract
The present invention relates to films or sheets of linear polyester having incorporated therein a combination of glass spheres and calcined clay having certain particle sizes and present in specific amounts based upon the weight of the polyester film. The addition of these fillers improves several properties of the film, including the handleability while maintaining acceptable optical clarity and transparency and to the method of making such films or sheets.
Claims15
A polyester film comprising a polyester polymer having incorporated therein a combination of (a) solid glass spheres having an average particle size of between 1 and 8 microns present in an amount ranging between 25 ppm and 350 ppm by weight based on the weight of the polymer and (b) calcined clay having an average particle size of less than 1 micron present in an amount not exceeding 10,000 ppm by weight based on the weight of the polymer.
A polyester film comprising a polyethylene terephthalate polymer having incorporated therein a combination of (a) solid glass spheres having an average particle size of between 2.0 and 4.0 microns and present in an amount ranging between 100 and 300 ppm by weight based on the weight of polymer, and (b) a calcined clay having an average particle size of between 0.25 and 0.75 microns and present in a range of between 1,000 and 5,000 ppm by weight based on the weight of polymer.
A polyester film comprising a polyester polymer having incorporated therein a combination of (a) solid glass spheres having an average particle size of between 1 and 8 microns present in an amount ranging between 30 ppm and 350 ppm by weight based on the weight of the polymer and (b) calcined clay having an average particle size of less than 1 micron present in an amount not exceeding 10,000 ppm by weight based on the weight of the polymer, having one or both surfaces of said film coated with a coating layer.
Dependencies are inferred from the claim text.