Foaming agent masterbatches for foaming thermoplastic vulcanizates

Patent metadata

Field	Value
Publication number	US-10508184-B2
Application number	US-201715809294-A
Country	US
Kind code	B2
Filing date	Nov 10, 2017
Priority date	Dec 29, 2016
Publication date	Dec 17, 2019
Grant date	Dec 17, 2019

Abstract

The present disclosure relates to thermoplastic vulcanizate (TPV) compositions and foaming agent masterbatches suitable for foaming, as well as foamed TPV compositions, methods of making the foregoing, and applications of various foamed TPV compositions. In particular, the present disclosure provides foaming agent masterbatches having unconventionally lower loading of foaming agent in carrier polymer. The carrier polymer may advantageously comprise or be a plastomer and/or propylene-based elastomer that is also suitable for inclusion in the TPV composition, and foaming the TPV composition may include the use of relatively greater amounts of foaming agent masterbatch. The use of greater amounts of foaming agent masterbatch with lower loading may allow for superior distribution of the foaming agent in the TPV composition during foaming, leading to greater uniformity of extent of foaming (e.g., as may be shown through greater uniformity of specific gravity in the foamed TPV composition).

First claim

What is claimed is:

1. A method comprising:
(a) combining 80 to 97 wt % of a thermoplastic vulcanizate (TPV) composition with 3 to 20 wt % of a foaming agent masterbatch;
wherein the TPV composition comprises (i) an at least partially vulcanized rubber component dispersed in a thermoplastic component comprising a thermoplastic resin and, optionally, a first portion of a plastomer and/or a first portion of a propylene-based elastomer; (ii) oil; and (iii) optionally, one or more additives;
further wherein the foaming agent masterbatch comprises thermo-expandable microspheres in a carrier polymer comprising a second portion of the plastomer and/or a second portion of the propylene-based elastomer; and

(b) forming therefrom a foamed TPV composition comprising (i) the at least partially vulcanized rubber component dispersed in the thermoplastic component comprising the thermoplastic resin and one or more of the plastomer and the propylene-based elastomer; (ii) the oil; and (iii) the optional one or more additives;
wherein the first portion of each of the plastomer and/or the propylene-based elastomer is within the range from 0 to 75 wt % of the total amount of the plastomer and/or propylene-based elastomer, respectively, in the foamed TPV composition;
further wherein the second portion of each of the plastomer and/or the propylene-based elastomer forms the balance of the total amount of each of the plastomer and/or the propylene-based elastomer in the foamed TPV composition; and
further wherein the thermo-expandable microspheres have initiation temperature of at least 130° C., and further wherein all of the carrier polymer is capable of being melt processed at temperatures less than the initiation temperature.

2. The method of claim 1 , wherein all of the carrier polymer is capable of being melt processed at temperatures of 110° C. or less.

3. The method of claim 1 , wherein the plastomer, if present, comprises a copolymer of ethylene and one or more C 3 to C 10 α-olefins, has a density less than 0.915 g/cm 3 , melt index (ASTM D-1238 at 190° C., 2.16 kg load) between 0.10 and 20 dg/min, and has a melting point T m less than 110° C.

4. The method of claim 1 , wherein the carrier polymer comprises the second portion of the propylene-based elastomer, and further wherein the thermoplastic component of the TPV composition optionally comprises the first portion of the propylene-based elastomer such that the first portion of the propylene-based elastomer is within the range from 0 to 75 wt % of the total amount of the propylene-based elastomer in the foamed TPV composition.

5. The method of claim 4 , wherein each of (1) the thermoplastic component of the TPV composition, (2) the carrier polymer, and (3) the foamed TPV composition contains no plastomer.

6. The method of claim 4 , wherein the first portion of the propylene-based elastomer is within the range from 0 to 20 wt % of the total amount of the propylene-based elastomer in the foamed TPV composition, with the second portion of the propylene-based elastomer forming the balance of the total amount of the propylene-based elastomer in the foamed TPV composition.

7. The method of claim 4 , wherein the TPV composition comprises no propylene-based elastomer, and further wherein all of the propylene-based elastomer of the foamed TPV composition originates from the carrier polymer of the foaming agent masterbatch.

8. The method of claim 4 , wherein the carrier polymer consists of the propylene-based elastomer.

9. The method of claim 1 , wherein the propylene-based elastomer, if present, has at least 60 wt % units derived from propylene and the balance derived from ethylene and/or one or more C 4 to C 10 comonomers;
and further wherein the propylene-based elastomer has the following properties: (i) melt flow rate (MFR) of 1 to 5 g/10 min (ASTM D-1238, 230° C. and 2.16 kg), (ii) melting point (T m ) of 105° C. or less, and (iii) heat of fusion (H f ) within the range from 1 to 80 J/g.

10. The method of claim 1 , wherein the foaming agent masterbatch comprises 5 to 30 wt % of the thermo-expandable microspheres in 70 to 95 wt % of the carrier polymer.

11. The method of claim 1 , wherein the method comprises combining 88 to 95 wt % of the TPV composition with 5 to 12 wt % of the foaming agent masterbatch.

12. The method of claim 1 , wherein the foaming agent masterbatch comprises 7 to 25 wt % thermo-expandable microspheres in 75 to 93 wt % carrier polymer.

13. The method of claim 1 , wherein the rubber component comprises ethylene-propylene-diene (EPDM) terpolymer, and the thermoplastic resin comprises homopolypropylene.

14. The method of claim 1 , wherein the thermoplastic resin is polypropylene having MFR within the range from 0.1 to 5 g/10 min (ASTM D-1238, 230° C. and 2.16 kg).

15. A foamed TPV composition made by the method of claim 1 .

16. An article made from the foamed TPV composition of claim 15 .

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Shannon Porter C
• Antonini Charles L

Classifications

• C08J2323/12

  Polypropene · CPC title

• C08J3/226

  using a polymer as a carrier · CPC title

• C08J2423/14

  Copolymers of propene (C08J2423/16 takes precedence) · CPC title

• C08J2201/03

  Extrusion of the foamable blend · CPC title

• C08J2431/04

  Homopolymers or copolymers of vinyl acetate · CPC title