Adhesives for thermally shrinkable films or labels

• US 6,649,259 B1
• Filed: 02/29/2000
• Issued: 11/18/2003
• Est. Priority Date: 02/29/2000
• Status: Expired due to Term

• Current Assignee: Henkel IP & Holding GmbH (Henkel AG & Co KGaA)
• Original Assignee: National Starch and Chemical Investment Holding Corporation (Ingredion Incorporated)
• Inventors: Hu, Ziyi, Pierce, Peter D., Paul, Charles W.
• Primary Examiner(s): Seidleck, James J.
• Assistant Examiner(s): McClendon, Sanza L
• Application Number:
  US09/515,881
• Time in Patent Office: 1,358 Days
• Field of Search: 428/343, 428/355.R, 428/355.EP, 428/347, 428/349, 428/34.9, 428/35.1, 428/35.2, 428/35.5, 522/110, 522/111, 522/112, 522/100, 522/104, 522/170, 522/182, 264/497, 264/460, 264/813, 264/522
• US Class Current: 428/343
• CPC Class Codes: C09J 153/005 Modified block copolymers
• CPC Class Codes: C09J 2203/334 as a label
• CPC Class Codes: C09J 2453/00 Presence of block copolymer
• CPC Class Codes: C09J 7/387 Block-copolymers
• CPC Class Codes: Y10T 428/1328 Shrinkable or shrunk [e.g., due to heat, solvent, volatile agent, restraint removal, etc.]
• CPC Class Codes: Y10T 428/1331 Single layer [continuous layer]
• CPC Class Codes: Y10T 428/1334 Nonself-supporting tubular film or bag [e.g., pouch, envelope, packet, etc.]
• CPC Class Codes: Y10T 428/1345 Single layer [continuous layer]
• CPC Class Codes: Y10T 428/28 Web or sheet containing structurally defined element or component and having an adhesive outermost layer
• CPC Class Codes: Y10T 428/2817 Heat sealable
• CPC Class Codes: Y10T 428/2826 Synthetic resin or polymer

Abstract

Thermally shrinkable films or labels having coated thereon a radiation curable adhesive; and a process for applying thermally shrinkable films or labels to containers comprising the steps of a) coating at least a portion of a thermally shrinkable but unshrunken film or label segment with a radiation curable adhesive; b) applying the film or label to the longitudinal surface of the container; c) subjecting the radiation curable adhesive to a radiation source to effect curing thereof and, d) subjecting the container to heat to shrink the film or label onto the container so as to permanently affix it thereto.

Claims

1. A thermally shrinkable film or label having coated thereon a radiation curable adhesive composition comprising an epoxidized block copolymer and/or a cycloaliphatic epoxide, said adhesive composition having a viscosity at its application temperature of less than about 2,000 cps.

2. The thermally shrinkable film or label according to claim 1 wherein the radiation curable adhesive is coated beneath a transparent section of the thermally shrinkable film or label.

3. The thermally shrinkable film or label according to claim 1 wherein the radiation curable adhesive has a viscosity at its application temperature of less than about 1,000 cps.

4. The thermally shrinkable film or label according to claim 1 wherein the radiation curable adhesive composition comprises:

(a) from about 5 percent by weight to about 60 percent by weight of at least one epoxidized block copolymer;

(b) from about 20 percent by weight to about 85 percent by weight of at least one solid-hydrogenated tackifier;

(c) about 0.02 percent by weight to about 5 percent by weight of at least one cationic photoinitiator;

(d) about 0 percent by weight to about 40 percent by weight of at least one mineral oil;

(e) about 0 percent by weight to about 40 percent by weight of at least one liquid tackifier, and

(f) about 0 percent by weight to about 3 percent by weight of an antioxidant.

5. The thermally shrinkable film or lable according to claim 1 wherein the radiation curable adhesive composition comprises:

(a) from about 20 percent by weight to about 40 percent by weight of at least one epoxidized block copolymer;

(b) from about 50 percent by weight to about 70 percent by weight of at least one solid-hydrogenated tackifier;

(c) about 0.2 percent by weight to about 2 percent by weight of at least one cationic photoinitiator;

(d) about 0 percent by weight to about 25 percent by weight of at least one mineral oil; and

(e) about 0 percent by weight to about 1.5 percent by weight of at least one hindered phenol antioxidant.

6. The thermally shrinkable film or label according to claim 1 wherein the radiation curable adhesive composition comprises:

(a) from about 10% by weight to about 50% by weight of at least one epoxidized cycloaliphatic base resin;

(b) from about 0.1% by weight to about 2.0% by weight of at least one cationic photoinitiator;

(c) from about 0% by weight to about 80% by weight of at least one solid or liquid polyester diol; and

(d) from about 0% by weight to about 60% by weight of at least one polar tackifier.

7. The thermally shrinkable film or label according to claim 1 wherein the radiation curable adhesive comprises:

(a) from about 20% by weight to about 30% by weight of at least one epoxidized cycloaliphatic base resin;

(b) from about 1.0% by weight to about 2.0% by weight of at least one cationic photoinitiator;

(c) from about 60% by weight to about 80% by weight of at least one solid or liquid polyester diol; and

(d) from about 0% by weight to about 100/by weight of at least one polar tackifier.

8. A process for applying a thermally shrinkable film or label to a container comprising the steps of:

(a) coating a radiation curable adhesive on at least a portion of a thermally shrinkable but unshrunken film or label segment;

(b) applying the film or label to the longitudinal surface of the container;

(c) subjecting the radiation curable adhesive to a radiation source to effect curing thereof; and

(d) subjecting the container to heat to shrink the film or label onto the container so as to permanently affix it thereto.

9. The process according to claim 8, wherein the radiation curable adhesive has a viscosity at its application temperature of less than about 2,000 cps.

10. The process according to claim 8, wherein the radiation curable adhesive has a viscosity at its application temperature of less than about 1,000 cps.

11. The process according to claim 8 wherein the radiation curable adhesive comprises:

(a) from about 5 percent by weight to about 60 percent by weight of at least one epoxidized block copolymer;

(b) from about 20 percent by weight to about 85 percent by weight of at least one solid-hydrogenated tackifier;

(c) about 0.02 percent by weight to about 5 percent by weight of at least one cationic photoinitiator;

(d) about 0 percent by weight to about 40 percent by weight of at least one mineral oil;

(e) about 0 percent by weight to about 40 percent by weight of at least one liquid tackifier; and

(f) about 0 percent by weight to about 3 percent by weight of an antioxidant.

12. The process according to claim 8 wherein the radiation curable adhesive composition comprises:

(a) from about 20 percent by weight to about 40 percent by weight of at least one epoxidized block copolymer;

(b) from about 50 percent by weight to about 70 percent by weight of at least one solid-hydrogenated tackifier;

(c) about 0.2 percent by weight to about 2 percent by weight of at least one cationic photoinitiator;

(d) about 0 percent by weight to about 25 percent by weight of at least one mineral oil; and

(e) about 0 percent by weight to about 1.5 percent by weight of at least one hindered phenol antioxidant.

13. The process according to claim 8 wherein the radiation curable adhesive composition comprises:

(a) from about 10% by weight to about 50% by weight of at least one epoxidized cycloaliphatic base resin;

(b) from about 0.1% by weight to about 2.0% by weight of at least one cationic photoinitiator;

(c) from about 0% by weight to about 80% by weight of at least one solid or liquid polyester diol; and

(d) from about 0% by weight to about 60% by weight of at least one polar tackifier.

14. The process according to claim 8 wherein the radiation curable adhesive composition comprises:

(a) from about 20% by weight to about 30% by weight of at least one epoxidized cycloaliphatic base resin;

(b) from about 1.0% by weight to about 2.0% by weight of at least one cationic photoinitiator;

(c) from about 60% by weight to about 80% by weight of at least one solid or liquid polyester diol; and

(d) from about 0% by weight to about 10% by weight of at least one polar tackifier.

15. The process according to claim 8 wherein the radiation curable adhesive is applied to a narrow longitudinal region of the container or of the leading end of the film segment to secure the leading end of the film to the container, the film wrapped around the container and the film segment secured to the container by overlapping the trailing end, a narrow region of which has been coated with the radiation curable adhesive.

16. The process of claim 8 wherein the adhesive is coated at a leading end and/or a trailing end of said film or label.

17. The process of claim 16 wherein the film or label is applied to the surface of the container by securing the leading end of the film or label to said surface and wrapping the film or label around to container such that the trailing end overlaps the leading end.