Adhesives made from polymer systems

Patent metadata

Field	Value
Publication number	US-9290680-B2
Application number	US-201414474406-A
Country	US
Kind code	B2
Filing date	Sep 2, 2014
Priority date	Mar 27, 2009
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

The present invention relates to an adhesive, comprising at least one polymer system obtained by a process for reducing the melt viscosity of at least one polymer blend starting material, wherein the process comprises the step of treating at least one polymer blend with at least one radical donor under shear stress at a temperature above the softening point of said polymer blend.

First claim

The invention claimed is:

1. An adhesive made by the process of:
(A) degrading a polymer system with a radical donor until the degraded polymer system has a melt viscosity of less than 50% than the non-degraded polymer at 200° C.; and
(B) adding a tackifier;
wherein the degraded polymer system of the resulting adhesive consists of (a) 30 to 70 wt % of an elastomeric rubber selected from the group consisting of ethylene-propylene rubber copolymer, ethylene-propylene-diene rubber terpolymer, and mixtures thereof and (b) 30 to 70 wt % a semi-crystalline olefinic polymer or a blend of semi-crystalline olefinic polymers;
wherein the semi-crystalline olefinic polymer has a heat of melting from 20 to 95 J/g;
wherein the degraded polymer system is present at a level greater than 30 wt %, based on the total weight of the adhesive; and
wherein the molecular weight distribution Mw/Mn of the degraded polymer system ranges from 1.6 to 4.0.

2. The adhesive of according to claim 1 , wherein the elastomeric rubber comprises less than 35% of ethylene.

3. The adhesive according to claim 1 , wherein the degraded polymer system has an elongation at break of at least 50% determined according to EN ISO 527-3.

4. The adhesive according to claim 1 , wherein the degraded polymer system has a tensile strength at break of at least 2.5 MPa determined according to EN ISO 527-3.

5. The adhesive according to claim 1 , wherein the elastomeric rubber is ethylene-propylene rubber copolymer that contains at least 40 percent by weight of ethylene.

6. The adhesive according to claim 1 , wherein the elastomeric rubber is ethylene-propylene rubber copolymer that contains 15 to 50 percent by weight of propylene.

7. The adhesive according to claim 1 , wherein the elastomeric rubber is ethylene-propylene-diene rubber terpolymer that contains 40 to 80 percent by weight of ethylene, 15 to 50 percent by weight of propylene, and 2 to 15 percent by weight of a diene.

8. The adhesive according to claim 7 , wherein the ethylene-propylene-diene rubber terpolymer contains 20 to 45 percent by weight of propylene.

9. The adhesive according to claim 8 , wherein the diene is selected from the group consisting of 1,4-hexadiene, norbornadiene, ethylidene-norbornene, dicyclopentadiene, butadiene and isoprene.

10. The adhesive according to claim 1 , wherein the semi-crystalline olefinic polymer is a copolymer of ethylene present at 1 to 35 wt % and at least one comonomer present at 65 to 99 wt % selected from the group consisting of C3-C20 alpha-olefins.

11. The adhesive according to claim 1 , wherein the radical donor is selected from azo compounds, diazo compounds or peroxides.

12. The adhesive according to claim 1 , wherein the adhesive comprises greater than 40 wt %, based on the total weight of the adhesive, of the degraded polymer system.

13. The adhesive according to claim 12 , wherein the adhesive comprises greater than 50 wt %, based on the total weight of the adhesive, of the degraded polymer system.

14. An adhesive made by the process of:
(A) degrading a polymer system with a radical donor until the degraded polymer system has a melt viscosity of less than 50% than the non-degraded polymer at 200° C.; and
(B) adding a tackifier and a plasticizer;
wherein the polymer system consists of (a) 30 to 70 wt % of an elastomeric rubber selected from the group consisting of ethylene-propylene rubber copolymer, ethylene-propylene-diene rubber terpolymer, and mixtures thereof and (b) 30 to 70 wt % a semi-crystalline olefinic polymer or a blend of semi-crystalline olefinic polymers;
wherein the semi-crystalline olefinic polymer has a heat of melting from 20 to 95 J/g;
wherein the degraded polymer is present at a level greater than 30 wt %, based on the total weight of the adhesive;
wherein the plasticizer present at a level less than 5 wt %, based on the total weight of the adhesive; and
wherein the molecular weight distribution Mw/Mn of the degraded polymer system ranges from 1.6 to 4.0.

15. An adhesive made by the process of:
(A) degrading a polymer system with an azo compound, a diazo compound or a peroxide until the degraded polymer system has a melt viscosity of less than 50% than the non-degraded polymer at 200° C.; and
(B) adding a tackifier and a plasticizer;
wherein the degraded polymer system of the resulting consists of (a) 50 to 80 wt % of an elastomeric rubber selected from the group consisting of ethylene-propylene rubber copolymer, ethylene-propylene-diene rubber terpolymer, and mixtures thereof and (b) 20 to 50 wt % a semi-crystalline olefinic polymer or a blend of semi-crystalline olefinic polymers;
wherein the semi-crystalline olefinic polymer has a heat of melting from 20 to 95 J/g;
wherein the degraded polymer system is present at a level greater than 40 wt %, based on the total weight of the adhesive; and
wherein the molecular weight distribution Mw/Mn of the degraded polymer system ranges from 1.0 to 4.0.

Assignees

• Henkel Ag & Co Kgaa
• Henkel IP & Holding GmbH

Inventors

• Kasper Dirk
• Mueller Thomas
• Hoffmann Gunter
• Hoffmann Knut
• Swain Andy
• Yaacoub Claudia
• Dejesus Maria Cristina Barbosa

Classifications

• C08L23/08 Primary

  Copolymers of ethene (C08L23/16 takes precedence) · CPC title

• C08L2666/06

  Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof · CPC title

• C08L2205/02

  containing two or more polymers of the same C08L -group · CPC title

• C08L23/16

  Ethylene-propylene or ethylene-propylene-diene copolymers · CPC title

• C08F210/06

  Propene · CPC title