Polyester resin compositions for calendering

• US 6,846,440 B2
• Filed: 10/31/2002
• Issued: 01/25/2005
• Est. Priority Date: 03/17/1998
• Status: Expired due to Term

• Current Assignee: Eastman Chemical Company
• Original Assignee: Eastman Chemical Company
• Inventors: Moolenaar, Hubertus Jacobus Wilhelmus, McConnell, Richard Leon, Flynn, Paul Mary, Sanders, Timothy Michael
• Primary Examiner(s): Vargot, Mathieu D.
• Application Number:
  US10/284,615
• Publication Number:
  US 20030065075A1
• Time in Patent Office: 817 Days
• Field of Search: 264/132, 264/175, 264/300, 264/319, 264/173.1, 264/173.18, 264/292, 425/363, 428/141, 524/180, 524/270
• US Class Current: 264/132
• CPC Class Codes: C08G 63/181 Acids containing aromatic rings
• CPC Class Codes: C08J 2367/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds; C08J2367/06 takes precedence
• 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 5/098 Metal salts of carboxylic acids
• CPC Class Codes: C08K 5/103 with polyalcohols
• CPC Class Codes: C08K 5/20 Carboxylic acid amides
• 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

Abstract

A polyester resin composition is calendered to produce a film or a sheet. The polyester resin composition is a polyester having a crystallization half time from a molten state of at least 5 minutes combined with an additive for preventing sticking of the polyester to calendering rolls.

Claims

1. A process for preparing a film or sheet from a polyester resin composition comprising the steps of:

(a) selecting as the polyester component of the resin an amorphous polyester, or a semi-crystalline polyester which has a crystallization half time from a molten state of at least 5 minutes where the crystallization half-time is measured in a differential scanning calorimeter (DSC) by providing a 15.0 mg sample of the polyester which is sealed in an aluminum pan and heated to 290°

C. at a rate of 3200°

C. per minute for 2 minutes, cooling the sample immediately to a predetermined isothermal crystallization temperature at a rate of 320°

C. per minute in the presence of helium; and

noting the time span from reaching the isothermal crystallization temperature to the point of a crystallization peak of the DSC curve, which time span is defined as the crystallization half time; and

(b) calendering the polyester by introducing the polyester resin composition in pellet, powder or melt form between at least two adjacent heated calendering rolls thereby to form the sheet or film, wherein the polyester component of the resin is selected from polyesters which consist of (i) at least 80 mole % of a diacid residue component selected from terephthalic acid, naphthalene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid and mixtures thereof and (ii) 80 to 100 mole % of a diol residue component selected from diols containing 2 to 10 carbon atoms and mixtures thereof and 0 to 20 mole % of a modifying diol selected from 1,3 propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 hexanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, propylene glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol;

wherein the diacid residue component is based upon 100 mole % diacid residue and the diol residue is based upon 100 mole % diol residue, and wherein the resin composition includes an additive which is an internal lubricant or slip agent, or a mixture thereof, and the amount of additive added in the resin composition is from 0.01 to 10 wt % based on the total weight of the resin composition, and the additive being effective to prevent sticking of the polyester resin composition to the calendering rolls during calendering.

2. The process of claim 1 wherein during the step of calendering, the polyester resin composition is passed through a compressive nip between the calendering rolls at temperatures of about 130°

to about 250°

C.

3. The process of claim 1 wherein during the step of calendering, the polyester resin composition is passed through a compressive nip between the calendering rolls at temperatures of about 140°

to about 190°

C.

4. The process of claim 1 wherein the crystallization half time of the polyester is at least 12 minutes.

5. The process of claim 1 wherein the polyester is amorphous and thus has a crystallization half time of infinity.

6. The process of claim 1 wherein the diol residue component is selected from ethylene glycol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanedimethanol, and mixtures thereof.

7. The process of claim 6 wherein the diol residue component comprises from 10 to 100 mole percent 1,4-cyclohexanedimethanol and from 90 to 0 mole percent ethylene glycol.

8. The process of claim 1 wherein the diacid residue component consist of 80 to 100 mole % of the diacid residue component selected from terephthalic acid, naphthalene dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, isophthalic acid and mixtures thereof and 0 to 20 mole % of a modifying diacid containing 4 to 40 carbon atoms.

9. The process of claim 8 wherein the modifying diacid is selected from succinic acid, glutaric acid, azelic acid, adipic acid, suberic acid, sebacic acid, and dimer acid.

10. The process of claim 1 wherein the lubricant or slip agent, or mixture thereof is/are selected from:

fatty acid amides;

metal salts of organic acids;

fatty acids and esters;

hydrocarbon waxes;

chemically modified polyolefin waxes;

ester waxes;

glycerol mono- and di-stearates;

talc; and

acrylic copolymers.

11. The process of claim 1 wherein the resin composition further comprises an oxidative stabilizer.

12. The process of claim 11 wherein the oxidative stablizer is selected from distearyl thiodipropionate or dilauryl thiodipropanoate;

phenolic stabilizers, butylated hydroxytoluene; and

phosphorus containing stabilizers.

13. The process of claim 1 wherein the resin composition further comprises a melt strength enhancer.

14. The process of claim 13 wherein the melt strength enhancer is a branching agent added in an amount of 0.1 to 2.0 mole %.

15. The process of claim 14 wherein the branching agent is selected from trimellitic acid, trimellitic anhydride, pyromellitic dianhydride, trimethylolpropane, glycerol, pentaerythritol, citric acid, tartaric acid, and 3-hydroglutaric acid.

16. The process of claim 1 wherein the film or sheet is further thermoformed into shaped packaging.

17. The process of claim 1 wherein the film or sheet is further printed on with ink.

18. The process of claim 17 wherein the film or sheet is laminated either in-line or off-line with fabric or other plastics films or sheets.

19. The process of claim 1 wherein the film or sheet is further formed into:

works of graphic art, transaction cards, security cards, veneers, wall coverings, book bindings or folders.