Heat resistant ethylene vinyl acetate copolymer composition and process for its production

Patent metadata

Field	Value
Publication number	US-9803073-B2
Application number	US-201615059442-A
Country	US
Kind code	B2
Filing date	Mar 3, 2016
Priority date	Nov 20, 2013
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

Disclosed herein are curable heat resistant ethylene vinyl acetate copolymer-polyamide blend compositions, wherein the ethylene vinyl acetate copolymer has a melting peak temperature of 100° C. or less. The blend compositions comprise 0.1 to 10 weight percent dispersed polyamide, and may be cured to form articles having improved heat resistance while maintaining the desirable physical properties of unmodified, cured ethylene vinyl acetate articles.

First claim

What is claimed is:

1. A heat resistant curable ethylene vinyl acetate (EVA) copolymer-polyamide blend composition comprising:
(A) from about 99 wt % to about 95 wt % of an EVA component selected from the group consisting of
(i) one or more amorphous EVA copolymers;
(ii) one or more EVA copolymers having a melting peak temperature of 100° C. or less; and
(iii) a combination of two or more of the amorphous EVA copolymers and the EVA copolymers having a melting peak temperature of 100° C. or less;

(B) from about 1 wt % to about 5 wt % of one or more polyamides;
wherein the weight percent of the polyamides and the EVA component are based on the total combined amount of EVA component and polyamides in the blend composition, the blend composition has a Mooney viscosity determined according to ASTM D1646, ML 1+4 at 100° C. less than 200, and the blend composition comprises polyamide particles dispersed in a continuous EVA copolymer matrix; and
(C) a peroxide curative;
wherein said curable composition, upon curing, forms a thermoset material.

2. The composition of claim 1 wherein the amorphous EVA copolymer or the EVA copolymer having a melting peak temperature of 100° C. or less comprises from about 18 wt % to about 90 wt % of vinyl acetate based on the weight of the EVA.

3. The composition of claim 1 wherein the EVA component has a Mooney viscosity determined according to ASTM D1646, ML 1+4 at 100° C. of less than 120.

4. The composition of claim 1 wherein each of the one or more polyamides has a melting peak temperature of less than about 270° C. as determined according to ASTM D3418-08.

5. The composition of claim 4 wherein each of the one or more polyamides has a melting peak temperature of less than 160° C.

6. The composition of claim 1 wherein at least one of said one or more polyamides is selected from nylon 6, nylon 6/6 or combinations thereof.

7. The composition of claim 1 wherein said composition has an increase in torque MH-ML of at least 2.5 dN-m when tested in a rotorless cure meter at conditions of 177° C. for 24 minutes per ASTM D5289-07a.

8. An article produced from the blend composition of claim 1 .

9. The article of claim 8 wherein said article is wire or cable jacketing, spark plug boot, hose, belt, molded boot, seal, gasket, tubing, hose or grommet.

10. The composition of claim 1 , further comprising one or more additives selected from the group consisting of fillers, plasticizers, pigments, antioxidants, process aids, waxes, and colorants.

11. The composition of claim 1 , further comprising one or more polymers with amine or acid reactive functionality, or further comprising one or more elastomers.

12. A process for producing a heat resistant curable EVA copolymer-polyamide blend composition, wherein said curable composition, upon curing, forms a thermoset material; said curable composition comprising:
(A) from about 99.9 wt % to about 90 wt % of an EVA component selected from the group consisting of
(i) one or more amorphous EVA copolymers;
(ii) one or more EVA copolymers having a melting peak temperature of 100° C. or less; and
(iii) a combination of two or more of the amorphous EVA copolymers and the EVA copolymers having a melting peak temperature of 100° C. or less;

(B) from about 0.1 wt % to about 10 wt % of one or more polyamides;
wherein the weight percent of the polyamides and the EVA component are based on the total combined amount of EVA component and polyamides in the blend composition, the blend composition has a Mooney viscosity determined according to ASTM D1646, ML 1+4 at 100° C. less than 200, and the blend composition comprises polyamide particles dispersed in a continuous EVA copolymer matrix; and
(C) a peroxide curative; and

said process comprising the steps of:
(A) providing said EVA component;
(B) providing said one or more polyamides, wherein each of the one or more polyamides has a melting peak temperature;
(C) mixing the EVA component and the one or more polyamides at a temperature that is:
(i) greater than the melting peak temperatures of the one or more polyamides; and
(ii) greater than the melting peak temperatures of the one or more EVA copolymers, when the EVA component comprises the one or more EVA copolymers having a melting peak temperature of 100° C. or less;
wherein said mixing disperses said one or more polyamides in said EVA component to form an EVA copolymer-polyamide blend composition;

(D) maintaining the temperature of the EVA copolymer-polyamide blend composition at less than 160° C., or cooling the EVA copolymer-polyamide blend composition to a temperature of less than 160° C.
wherein said temperature of less than 160° C. is below the decomposition temperature of the peroxide and below the temperature at which the crosslinking reaction occurs; and

(E) adding the peroxide curative to the EVA copolymer-polyamide blend composition at the temperature of less than 160° C. to form the heat resistant curable ethylene vinyl acetate (EVA) copolymer-polyamide blend composition.

13. The process of claim 12 ,
wherein the mixing of step (C) disperses the one or more polyamides in the EVA component to form an intermediate blend composition; said intermediate blend composition comprising about 0.1 to about 60 wt % of the one or more polyamides and about 40 to about 99.9 wt % of the EVA component; and
wherein the intermediate blend composition has a Mooney viscosity (ML1+4, 100° C.) according to ASTM D-1646 of less than 200; and
further comprising the step of:
mixing the intermediate blend composition with one or more additional EVA copolymers, said one or more additional EVA copolymers having melting peak temperatures of 100° C. or less, to form the EVA copolymer-polyamide blend composition.

14. The process of claim 13 in which the curable composition exhibits an increase in torque MH-ML of at least 2.5 dN-m when tested in a rotorless cure meter at conditions of 177° C. for 24 minutes per ASTM D5289-07a.

15. The process of claim 13 , wherein the EVA component comprises said EVA copolymers having melting peak temperatures of 100° C. or less, and said one or more additional EVA copolymers are the same as the one or more EVA copolymers in the intermediate blend composition.

16. The process of claim 13 , wherein the EVA component comprises said EVA copolymers having melting peak temperatures of 100° C. or less, and said one or more additional EVA copolymers are different from the one or more EVA copolymers in the intermediate blend composition.

17. The process of claim 12 in which the curable composition exhibits an increase in torque MH-ML of at least 2.5 dN-m when tested in a rotorless cure meter at conditions of 177° C. for 24 minutes per ASTM D5289-07a.

18. A process for producing a heat resistant curable EVA copolymer-polyamide blend composition, wherein said curable composition, upon curing, forms a thermoset material; said curable composition comprising:
(A) from about 99.9 wt % to about 90 wt % of an EVA component selected from the group consisting of
(i) one or more amorphous EVA copolymers;
(ii) one or more EVA copolymers having a melting peak temperature of 100° C. or less; and
(iii) a combination of two or more of the amorphous EVA copolymers and the EVA copolymers having a melting peak temperature of 100° C. or less;

(B) from about 0.1 wt % to about 10 wt % of one or more polyamides;
wherein the weight percent of the polyamides and the EVA component are based on the total combined amount of EVA component and polyamides in the blend composition,

Assignees

• Du Pont

Inventors

• Oriani Steven R
• Stewart Mark Aaron

Classifications

• C08J3/24

  Crosslinking, e.g. vulcanising, of macromolecules (mechanical aspects B29C35/00; crosslinking agents C08K) · CPC title

• C08J2477/00

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

• Y10T428/139

  Open-ended, self-supporting conduit, cylinder, or tube-type article · CPC title

• C08L2312/00

  Crosslinking · CPC title

• C08J2331/04

  Homopolymers or copolymers of vinyl acetate · CPC title