Shrink wrap label coating to facilitate recycling

Patent metadata

Field	Value
Publication number	US-10643501-B2
Application number	US-201815967818-A
Country	US
Kind code	B2
Filing date	May 1, 2018
Priority date	Aug 21, 2013
Publication date	May 5, 2020
Grant date	May 5, 2020

Abstract

The present disclosure relates to a coating composition used to form a bond in the seam area of a label substrate material that wraps around an article and is shrunk in conformance to the size and shape of the article. The coating composition is comprised of at least first and second resins, and in some instances, third resins as described herein. The coating composition provides good bond strength in the seam area of the label, and the coating composition and/or each of the resins thereof may be at least partially hydrolysable but not solutionable in a hot caustic bath, enabling separation of the label from the article during recycling. Further disclosed is a method providing for the separation of labels from the articles, and further disclosed are labeled articles employing the coating compositions.

First claim

What is claimed is:

1. A coating composition comprising:
a) at least one first polyester resin having a Tg or a softening point from 25° C. to 115° C.;
b) at least one second polyester resin having a Tg or a softening point lower than the Tg or softening point of the first resin; and
c) a third resin, wherein the third resin is hydrogenated rosin.

2. A method of detaching a label substrate from an article comprising the steps of:
placing an article having an attached label substrate into a hot caustic solution, the label substrate having a coating composition applied thereto to attach the label substrate to the article;
detaching the label substrate from the article, wherein the detaching occurs upon exposure of the coating composition to the hot caustic solution, the coating composition comprising:
a) at least one first resin with a Tg or a softening point from 25° C. to 115° C.;
b) at least one second resin having a Tg or a softening point lower than the Tg or softening point of the first resin; and
wherein the coating composition and/or each of the resins in the coating composition are at least partially hydrolysable but not solutionable in a hot caustic bath, and the coating composition, when applied to a label, enables removal of the label during recycling.

3. The method of claim 2 , wherein at least one of the first and second resins in the coating composition is a polyester resin.

4. The method of claim 2 , wherein the first and second resins in the coating composition are polyester resins.

5. The method of claim 2 , wherein the coating composition comprises hydrogenated rosin as a third resin.

6. The method of claim 4 , wherein the coating composition comprises hydrogenated rosin as a third resin.

7. The method of claim 2 , wherein the label substrate is a shrink sleeve label substrate that has been shrunk to conform to the article.

8. The method of claim 2 , wherein the label substrate comprises a seam comprised of the coating composition, and wherein the detaching comprises opening the seam.

9. The method of claim 2 , further comprising the step of recycling the article from which the label substrate has been detached.

10. The method of claim 9 , wherein at least one of the first and second resins in the coating composition is a polyester resin.

11. The method of claim 9 , wherein the first and second resins in the coating composition are polyester resins.

12. The method of claim 9 , wherein the coating composition comprises hydrogenated rosin as a third resin.

13. The method of claim 11 , wherein the coating composition comprises hydrogenated rosin as a third resin.

14. The method of claim 9 , wherein the label substrate is a shrink sleeve label substrate that has been shrunk to conform to the article.

15. The method of claim 9 , wherein the label substrate comprises a seam comprised of the coating composition, and wherein the detaching comprises opening the seam.

16. A method of detaching a label substrate from an article, comprising the steps of:
placing an article having an attached label substrate into a hot caustic solution, the label substrate having a coating composition applied thereto to attach the label substrate to the article; and
detaching the label substrate from the article, wherein the detaching occurs upon exposure of the coating composition to the hot caustic solution, the coating composition comprising:
a) at least first and second resins; and
b) two or more solvents, wherein one of the solvents is a seam-welding solvent present in the composition in an amount, based on the total composition weight, of 0.1 wt % to 20 wt %; preferably in an amount of 0.1 wt % to 15 wt %; more preferably in an amount of 0.1 wt % to 10 wt %; and still more preferably in an amount of 0.1 wt % to 5 wt %.

17. The method of claim 16 , wherein the at least one of the first and second resins is a polyester resin.

18. The method of claim 16 , wherein the first and second resins are polyester resins.

19. The method of claim 16 , wherein the coating composition further comprises hydrogenated rosin as a third resin.

20. The method of claim 18 , wherein the coating composition further comprises hydrogenated rosin as a third resin.

21. The method of claim 16 , wherein the label substrate is a shrink sleeve label substrate that has been shrunk to conform to the article.

22. The method of claim 16 , wherein the label substrate comprises a seam comprised of the coating composition, and wherein the detaching comprises opening the seam.

23. The method of claim 16 , further comprising the step of recycling the article from which the label substrate has been detached.

24. The coating composition of claim 23 , wherein the at least one of the first and second resins is a polyester resin.

25. The coating composition of claim 23 , wherein the first and second resins are polyester resins.

26. The coating composition of claim 23 , wherein the coating composition further comprises hydrogenated rosin as a third resin.

27. The coating composition of claim 25 , wherein the coating composition further comprises hydrogenated rosin as a third resin.

28. The method of claim 23 , wherein the label substrate is a shrink sleeve label substrate that has been shrunk to conform to the article.

29. The method of claim 23 , wherein the label substrate comprises a seam comprised of the coating composition, and wherein the detaching comprises opening the seam.

Assignees

• Sun Chemical Corp

Inventors

• Schottland Philippe
• Mateuszczyk Robert
• Lucci Saverio
• Zha Yongping

Classifications

• B32B2307/736

  Shrinkable · CPC title

• C08J7/0427

  with only one layer of a composition containing a polymer binder (with more layers C08J7/042) · CPC title

• B32B2519/00

  Labels, badges · CPC title

• C08J2467/00

  Characterised by the use of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Derivatives of such polymers · CPC title

• C09J167/00

  Adhesives based on polyesters obtained by reactions forming a carboxylic ester link in the main chain (based on polyester-amides C09J177/12; based on polyester-imides C09J179/08); Adhesives based on derivatives of such polymers · CPC title