Thermally expandable formulations

Patent metadata

Field	Value
Publication number	US-9637067-B2
Application number	US-201514711958-A
Country	US
Kind code	B2
Filing date	May 14, 2015
Priority date	Nov 20, 2012
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

The present specification relates to thermally expandable formulations comprising (a) at least one peroxidically crosslinkable binary copolymer comprising at least one monomer unit selected from vinyl acetate, (meth)acrylic acids and derivatives thereof, the binary copolymer having a melt flow index of not more than 3 g/10 min, as determined in accordance with DIN EN ISO 1133 and with a test load of 2.16 kg and a test temperature of 190° C., (b) at least one peroxide, (c) at least one chemical blowing agent, and (d) at least one polymer based on one or more diene monomers, and (e) at least one terpolymer based on at least one first monomer selected from singly or multiply unsaturated hydrocarbons, and on at least one second monomer selected from (meth)acrylic acids and derivatives thereof. The thermally expandable formulations exhibit a high level of persistence during the heating of the material as required for curing/expansion.

First claim

The invention claimed is:

1. A thermally expandable composition, comprising:
(a) at least one peroxidically crosslinkable binary copolymer containing at least one monomer unit, selected from vinyl acetate, (meth)acrylic acids and derivatives thereof, wherein the binary copolymer has a melt flow index of no more than 3 g/10min, which is determined in accordance with DIN EN ISO 1133 with a test load of 2.16 kg and a test temperature of 190° C.,
(b) at least one peroxide,
(c) at least one chemical blowing agent and
(d) at least one polymer based on one or more diene monomers and
(e) at least one terpolymer based on at least one first monomer selected from the mono-or polyunsaturated hydrocarbons, and at least one second monomer selected from the (meth)acrylic acids and derivatives thereof.

2. The thermally expandable composition according to claim 1 , wherein the peroxidically crosslinkable polymer (a) is selected from ethylene-vinyl acetate copolymers, functionalized ethylene-vinyl acetate copolymers, ethylene-butyl acrylate copolymers, functionalized ethylene-butyl acrylate copolymers, ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers, ethylene-(meth)acrylic acid copolymers and ethylene-2-ethylhexyl acrylate copolymers and mixtures thereof.

3. The thermally expandable composition according to claim 1 , comprising as component (a) an ethylene-vinyl acetate copolymer.

4. The thermally expandable composition according to claim 1 , comprising as component (c) a sulfonic acid hydrazide and/or azodicarbonamide.

5. The thermally expandable composition according to claim 1 , wherein the polymer (d) is selected from polybutadiene homopolymers, polyisoprene homopolymers and butadiene-isoprene copolymers.

6. The thermally expandable composition according to claim 1 , wherein the polymer (d) has a syndiotactic structure.

7. The thermally expandable composition according to claim 1 , wherein the terpolymer (e) has a third monomer unit selected from styrene, glycidyl (meth)acrylic acid esters and maleic acid anhydride.

8. The thermally expandable composition according to claim 1 , wherein the composition additionally contains at least one low-molecular multifunctional acrylate.

9. The thermally expandable composition according to claim 1 , wherein the composition is essentially free of low-molecular multifunctional acrylates.

10. The thermally expandable composition according to claim 1 , wherein the composition additionally contains at least one hydrocarbon resin.

11. The thermally expandable composition according to claim 1 , comprising:
50 to 80% by weight of (a) the at least one peroxidically crosslinkable binary copolymer,
0.2 to 2% by weight of (b) the at least one peroxide,
5 to 18% by weight of (c) the at least one chemical blowing agent, and
wherein the terpolymer (e) is selected from:
styrene-butadiene-(meth)acrylate acids,
styrene-butadiene-(meth)acrylic acid esters,
ethylene-(meth)acrylic acid ester-glycidyl (meth)acrylic acid ester and/or
ethylene-(meth)acrylic acid ester-maleic acid anhydrides.

12. A baffle part for sealing a cavity of a component, wherein the baffle part has a shape adapted to a cavity to be sealed and includes a thermally expandable composition according to claim 1 .

13. The baffle part according to claim 12 , wherein the baffle has at least one fastening element, which permits anchoring of the baffle in the cavity.

14. The baffle part according to claim 12 , wherein the baffle does not have a carrier structure.

15. A method for sealing a cavity of a component wherein a baffle part according to claim 11 is introduced into a cavity and is then heated to a temperature above 130° C. such that the thermally expandable composition expands and seals the cavity.

Assignees

• Henkel Ag & Co Kgaa

Inventors

• Kohlstrung Rainer
• Yamada Takehito

Classifications

• C08L2203/14

  used for foams · CPC title

• C08K5/23

  Azo-compounds · CPC title

• C08K5/14

  Peroxides · CPC title

• C08J2433/04

  esters · CPC title

• C08J2409/00

  Characterised by the use of homopolymers or copolymers of conjugated diene hydrocarbons · CPC title