High clarity films with improved thermal properties

• US 20050136271A1
• Filed: 12/06/2004
• Published: 06/23/2005
• Est. Priority Date: 12/18/2003
• Status: Active Grant

• Current Assignee: Candace Michele Tanner, Marc Alan Strand, Rodney Layne Piner, Ted Calvin Germroth
• Original Assignee: Candace Michele Tanner, Marc Alan Strand, Rodney Layne Piner, Ted Calvin Germroth
• Inventors: Germroth, Ted Calvin, Tanner, Candace Michele, Strand, Marc Alan, Piner, Rodney Layne
• Granted Patent: US 7,354,653 B2
• Time in Patent Office: Days
• US Class Current: 428/480
• CPC Class Codes: C08J 2367/00 Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain of polyester-amides C08J2377/12; of polyester-imides C08J2379/08; Derivatives of such polymers
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: C08K 5/0008 Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
• CPC Class Codes: C08K 5/09 Carboxylic acids; Metal salts thereof; Anhydrides thereof
• CPC Class Codes: C08K 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08K 5/20 Carboxylic acid amides
• CPC Class Codes: C08L 2666/02 Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• CPC Class Codes: C08L 2666/26 Natural polymers, natural resins or derivatives thereof according to C08L1/00 - C08L5/00, C08L89/00, C08L93/00, C08L97/00 or C08L99/00
• CPC Class Codes: C08L 3/02 Starch; Degradation products thereof, e.g. dextrin
• CPC Class Codes: C08L 67/00 Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain of polyester-amides C08L77/12; of polyester-imides C08L79/08; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 67/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds C08L67/06 takes precedence
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence
• CPC Class Codes: C08L 91/06 Waxes
• CPC Class Codes: Y10T 428/1352 Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/23 Sheet including cover or casing
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31794 Of cross-linked polyester

Abstract

Disclosed are high clarity films produced from semicrystalline polyesters by calendering. These films unexpectedly develop a higher peak melting point, which leads to higher thermal resistance. The semicrystalline polyesters may be biodegradable. When these calendered films are oriented, they develop unexpectedly high physical strength or clarity in comparison to films that are prepared by conventional techniques.

Claims

1. A film comprising one or more semicrystalline polyesters and a release additive wherein said film is formed by a calendering process at a maximum temperature below the upper temperature of the melting point range of each of said one or more polyesters.

2. The film according to claim 1 wherein said film consists essentially of a polyester and release additive.

3. The film according to claim 1 wherein said film is substantially free of plasticizer.

4. The film according to claim 3 wherein said maximum temperature is within the melting point range of each of said one or more polyesters.

5. The film according to claim 3 wherein said one or more polyesters are biodegradable.

6. The film according to claim 5, wherein said one or more polyesters are selected from the group consisting of aliphatic-aromatic polyesters (“

AAPE”

), polycaprolactone, polylactic acid, polybutylenesuccinate, polyhydroxybutyrate, polyhydroxybutyrate-valerate, and copolymers thereof.

7. The film according to claim 4 or 6, wherein said one or more polyesters is an AAPE.

8. The film according to claim 7, wherein said AAPE comprises:

(a) diacid residues comprising adipic acid residues and 65 mole percent or less of terephthalic acid residues, based on the total moles of diacid residues; and

(b) diol residues comprising 1,4-butanediol residues.

9. The film according to claim 8, wherein said diacid residues comprise about 55 to about 60 mole percent of the residues of adipic acid and about 40 to about 45 mole percent of the residues of terephthalic acid, based on the total moles of diacid residues;

and said diol residues comprise are from about 95 to 100 mole percent of the residues of 1,4-butanediol, based on the total moles of diol residues.

10. The film according to claim 5 further comprising starch or talc.

11. The film according to claim 10, wherein said starch is a thermoplastic starch.

12. The film according to claim 5, wherein said film is free of antiblocking additives.

13. The film according to claim 5, wherein said release additive comprises about 0.1 to about 2.0 weight percent, based on the total weight of said film, at least compound selected from the group consisting of erucylamide, stearamide, calcium stearate, zinc stearate, stearic acid, montanic acid, montanic acid esters, montanic acid salts, oleic acid, palmitic acid, paraffin wax, polyethylene waxes, polypropylene waxes, carnauba wax, glycerol monostearate, and glycerol distearate.

14. The film according to claim 5, wherein said release additive comprises a fatty acid or a salt of a fatty acid containing more than 18 carbon atoms and an ester wax comprising a fatty acid containing more than 18 carbon atoms with an alcohol containing 2 to 28 carbon atoms.

15. The film according to claim 5, wherein said film has a lower percentage of haze than a melt-cast film having the substantially the same composition.

16. The film according to claim 5, wherein said film has a higher peak melting temperature than a melt-cast film having substantially the same composition.

17. The film according to claim 6, wherein at least one of said one or more polyesters have a crystallization half-time from a molten state of less than 5 minutes.

18. The film according to claim 6, wherein at least one of said one or more polyesters have a crystallization half-time from a molten state of less than 3 minutes.

19. The film according to claim 6, wherein said film has a lower percentage of haze than a melt-cast film having substantially the same composition.

20. The film according to claim 6, wherein said film has a higher peak melting temperature than a melt-cast film having substantially the same composition.

21. An oriented film comprising one or more semicrystalline polyesters and a release additive wherein said film is formed by a calendering process at a maximum temperature below the upper limit of the melting point range of each of said one or more polyesters and orienting said film by stretching in at least one direction.

22. The oriented film according to claim 21 wherein said film consists essentially of a polyester and release additive.

23. The oriented film according to claim 21 wherein said polyester composition is substantially free of plasticizer.

24. The oriented film according to claim 23 wherein said maximum temperature is within the melting point range of each of said one or more polyesters.

25. The oriented film according to claim 23 wherein said one or more polyesters are biodegradable.

26. The oriented film according to claim 25, wherein said one or more polyesters are selected from the group consisting of AAPE, polycaprolactone, polylactic acid, polybutylenesuccinate, polyhydroxybutyrate, polyhydroxybutyrate-valerate, or copolymers thereof.

27. The oriented film according to claim 24 or 26, wherein said one or more polyesters is an AAPE and is a linear or branched aliphatic-aromatic, random copolyester.

28. The oriented, film according to claim 27, wherein said-AAPE comprises:

(a) diacid residues comprising adipic acid residues and 65 mole percent or less of terephthalic acid residues; and

(b) diol residues comprising 1,4-butanediol residues.

29. The film according to claim 28, wherein said diacid residues comprise about 55 to about 60 mole percent of the residues of adipic acid and about 40 to about 45 mole percent of the residues of terephthalic acid, based on the total moles of diacid residues;

and said diol residues comprise about 95 to 100 mole percent of the residues of 1,4-butanediol, based on the total moles of diol residues.

30. The oriented film according to claim 25, further comprising starch or talc.

31. The oriented film according to claim 30, wherein starch is a thermoplastic starch.

32. The oriented film according to claim 25, wherein said film is free of anti-blocking additives.

33. The oriented film according to claim 25, wherein said release additive comprises at least one compound selected from the group consisting of erucylamide, stearamide, calcium stearate, zinc stearate, stearic acid, montanic acid, montanic acid esters, montanic acid salts, oleic acid, palmitic acid, paraffin wax, polyethylene waxes, polypropylene waxes, carnauba wax, glycerol monostearate, and glycerol distearate.

34. The oriented film according to claim 25, wherein said release additive comprises a fatty acid or a salt of a fatty acid containing more than 18 carbon atoms and an ester wax comprising a fatty acid containing more than 18 carbon atoms with an alcohol containing 2 to 28 carbon atoms.

35. The oriented film according to claim 25, wherein said film has a higher peak melting temperature than an oriented, melt-cast film having substantially the same composition.

36. The oriented film according to claim 25, wherein said film has a lower percentage of haze than an oriented, melt-cast film having substantially the same composition.

37. The oriented film according to claim 36, wherein said film has less than 5% haze.

38. The oriented film according to claim 37, wherein said film has less than 3% haze.

39. The oriented film according to claim 25, wherein said film has been stretched up to 600% elongation in one or more directions.

40. The oriented film according to claim 25, wherein at least one said one or more polyesters have a crystallization half-time from a molten state of less than 5 minutes.

41. The oriented film according to claim 40, wherein at least one of said one or more polyesters have a crystallization half-time from a molten state of less than 3 minutes.