Shrink wrap label coating to facilitate recycling

Patent metadata

Field	Value
Publication number	US-9976057-B2
Application number	US-201414911534-A
Country	US
Kind code	B2
Filing date	Jul 24, 2014
Priority date	Aug 21, 2013
Publication date	May 22, 2018
Grant date	May 22, 2018

Abstract

Provided is a coating composition that include a first resin having a Tg above about 25° C. and a second resin having a Tg above about 50° C. The coating composition and/or resins thereof are at least partially hydrolysable in a hot caustic solution. Further provided are a method for applying the coating composition to a label substrate, a label substrate coated with the coating composition, and a recycling method. Sleeve labels for articles such as containers may be formed from label substrates by forming a bonded seam with the coating composition. The coating composition maintains the bond in the seam during sleeve label shrinking and during article life. Label removal during recycling is relatively easy, as the coating composition in the seam de-bonds in a hot caustic solution.

First claim

We claim:

1. A coating composition comprising:
a) a first resin having a Tg above about 25° C.;
b) a second resin having a Tg above about 50° C.; and
wherein said coating composition is at least partially hydrolysable in a hot caustic solution.

2. The coating composition of claim 1 , wherein at least one of the first and second resins is a polyester resin.

3. The coating composition of claim 1 , wherein said coating composition or at least one of the resins is at least partially solutionable in a hot caustic solution.

4. The coating composition of claim 1 , wherein each of the resins in the coating composition is at least partially hydrolysable in a hot caustic solution.

5. The coating composition of claim 1 , wherein one resin has an acid value equal or greater than 25.

6. A coating composition comprising:
a) a first resin having a Tg above about 25° C.;
b) a second resin having a Tg above about 50° C.; and
wherein at least one of the resins is at least partially hydrolysable in a hot caustic solution.

7. The coating composition of claim 6 , wherein at least one of the first and second resins is a polyester resin.

8. The coating composition of claim 6 , wherein said coating composition or at least one of the resins is at least partially solutionable in a hot caustic solution.

9. The coating composition of claim 6 , wherein each of the resins in the coating composition is at least partially hydrolysable in a hot caustic solution.

10. The coating composition of claim 6 , wherein one resin has an acid value equal or greater than 25.

11. A method comprising applying a coating composition to a label substrate, wherein:
a) the label substrate is applied to a plastic article;
b) the coating enables removal of the label during recycling; and
c) the coating composition comprises:
i) a first resin having a Tg above about 25° C.;
ii) a second resin having a Tg above about 50° C.;

wherein said coating composition is at least partially hydrolysable in a hot caustic solution.

12. The method of claim 11 , wherein said coating composition or at least one of the resins is at least partially solutionable in a hot caustic solution.

13. The method of claim 11 , wherein each of the resins in the coating composition is at least partially hydrolysable in a hot caustic solution.

14. The method of claim 11 , wherein one resin has an acid value equal or greater than 25.

15. A method comprising applying a coating composition to a label substrate, wherein:
a) the label substrate is applied to a plastic article;
b) the coating enables removal of the label during recycling; and
c) the coating composition comprises:
i) a first resin having a Tg above about 25° C.;
ii) a second resin having a Tg above about 50° C.;

wherein at least one of the resins is at least partially hydrolysable in a hot caustic solution.

16. The method of claim 15 , wherein said coating composition or at least one of the resins is at least partially solutionable in a hot caustic solution.

17. The method of claim 15 , wherein one resin has an acid value equal or greater than 25.

18. The method of claim 15 , wherein each of the resins is at least partially hydrolysable in a hot caustic solution.

19. A label substrate coated with the coating composition of claim 1 .

20. A label substrate coated with the coating composition of claim 6 .

21. A label substrate coated with the coating composition of claim 9 .

22. A method of recycling an article comprising a label substrate, comprising the step of:
detaching the label substrate of claim 19 from an article in a hot caustic bath; and
recycling the article.

23. A method of recycling an article comprising a label substrate, comprising the step of:
detaching the label substrate of claim 20 from an article in a hot caustic bath; and
recycling the article.

24. A method of recycling an article comprising a label substrate, comprising the step of:
detaching the label substrate of claim 21 from an article in a hot caustic bath; and
recycling the article.

Assignees

• Sun Chemical Corp
• Schottland Philippe
• Mateuszczyk Robert
• Lucci Saverio
• Zha Yongping

Inventors

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

Classifications

• B29L2031/744

  Labels, badges, e.g. marker sleeves · CPC title

• B29B2017/0296

  Dissolving the materials in aqueous alkaline solutions, e.g. NaOH or KOH · CPC title

• B29B17/02

  Separating plastics from other materials · CPC title

• B08B9/083 Primary

  Removing scrap from containers, e.g. removing labels · CPC title

• C09D101/08

  Cellulose derivatives · CPC title