Propane diol-based polyester resin and shrink film
View Patent ↗A shrinkable polymer film including a modified polyester resin polymerized from monomers including a dicarboxylic acid and a glycol, wherein the glycol includes 2-methyl-1,3-propanediol, and wherein the polymer film shrinks at least about 50% in a main shrinkage direction after ten seconds in an 80 degree Celsius hot water bath.
1. A shrinkable polymer film comprising:
a modified polyester resin polymerized from monomers including a dicarboxylic acid and a glycol, wherein the glycol includes 2-methyl-1,3-propanediol,
and wherein the polymer film shrinks at least about 50% in a main shrinkage direction after ten seconds in an 80 degree Celsius hot water bath.
2. A label including the polymer film of claim 1 .
3. The polymer film of claim 1 , wherein the polymer film is transparent.
4. The polymer film of claim 1 , wherein the polyester resin has a glass transition temperature that is sufficiently high to render the polymer film resistant to shrinkage at temperatures normally experienced during shipping.
5. The polymer film of claim 1 , wherein the polyester resin has a glass transition temperature that is sufficiently high to render the polymer film non-sticky at room temperature.
6. The polymer film of claim 1 , wherein the polymer film has heat seal properties sufficient to seal the polymer film to itself under heat seal conditions of 90 degrees Celsius applied for 5 seconds with a pressure of 40 pounds per square inch.
7. The polymer film of claim 1 , wherein the 2-methyl-1,3-propanediol is present in the polyester resin at about 5 to about 50 mol percent.
8. The polymer film of claim 1 , wherein the 2-methyl-1,3-propanediol is present in the polyester resin at about 10 to about 35 mol percent.
9. The polymer film of claim 1 , wherein the 2-methyl-1,3-propanediol is present in the polyester resin at about 20 to about 30 mol percent.
10. The polymer film of claim 1 , wherein the 2-methyl-1,3-propanediol is present in the polyester resin at more than about 10 mol percent.
11. The polymer film of claim 1 , wherein the 2-methyl-1,3-propanediol is present in the polyester resin at about 50 to about 100 mol percent.
12. The polymer film of claim 1 , wherein the polymer film has a shrinkage in a main shrinking direction of at least about 50%.
13. The polymer film of claim 1 , wherein the polymer film has a shrinkage in a main shrinking direction of about 50% to about 80%.
14. The polymer film of claim 1 , wherein the polymer film has a shrinkage in a main shrinking direction of about 70% to about 80%.
15. The polymer film of claim 1 , wherein the glycol includes ethylene glycol.
16. The polymer film of claim 1 , wherein the glycol includes ethylene glycol and an additional glycol.
17. The polymer film of claim 1 , wherein the dicarboxylic acid includes terephthalic acid.
18. The polymer film of claim 1 , wherein the polymer film further includes an additional resin.
19. The polymer film of claim 18 , wherein the additional resin is PETG.
20. The polymer film of claim 18 , wherein the additional resin is polyethylene naphthalate.
21. The polymer film of claim 18 , wherein the additional resin is polystyrene.
22. The polymer film of claim 1 , further including a coating on the polymer film.
23. The polymer film of claim 22 , wherein the coating is aqueous.
24. The polymer film of claim 1 , wherein the polymer film has a thickness of about 10 to about 200 microns.
25. The polymer film of claim 1 , wherein the polymer film has a thickness of about 25 to about 100 microns.
26. The polymer film of claim 1 , wherein the polyester resin has a glass transition temperature of about 50 to about 72 degrees Celsius.
27. The polymer film of claim 1 , wherein the polyester resin has a glass transition temperature of about 55 to about 65 degrees Celsius.
28. A method of forming a polymer film comprising the step of:
extruding a modified polyester resin polymerized from monomers including a dicarboxylic acid and a glycol, wherein the glycol includes 2-methyl-1,3-propanediol, to form the polyester film,
wherein the polymer film shrinks at least about 50% in a main shrinkage direction after ten seconds in an 80 degree Celsius hot water bath.
29. The method of claim 28 , further including the step of applying a coating to the polymer film in-line during film manufacture.
30. The method of claim 28 , further including the step of applying heat to the polymer film during manufacture.
31. The method of claim 28 , further including the step of applying heat to the polymer film after manufacture to achieve shrinkage.
32. The method of claim 31 , wherein maximum shrinkage is reached at less than about 80 degrees Celsius.
33. The method of claim 28 , further including the step of orienting the polyester film in at least one direction.
34. The method of claim 33 , wherein the polymer film is stretched from about two to about ten times in a main stretching direction.
35. The method of claim 33 , wherein the polymer film is stretched from about four to about seven times in a main stretching direction.