Methods of making an elastomer composite reinforced with silica and products containing same

Patent metadata

Field	Value
Publication number	US-10882964-B2
Application number	US-201916403725-A
Country	US
Kind code	B2
Filing date	May 6, 2019
Priority date	Jul 15, 2015
Publication date	Jan 5, 2021
Grant date	Jan 5, 2021

Abstract

Methods to make a silica elastomer composite with a destabilized dispersion of a never-dried, or as-produced, precipitated silica are described, along with silica elastomer composites made from the methods. The advantages achieved with the methods are further described.

First claim

What is claimed is:

1. A method of producing a silica elastomer composite, comprising:
providing a first fluid comprising a destabilized dispersion of silica with silica present in an amount of from 6 to 35 weight percent, and said first fluid having a first fluid volumetric flow rate wherein said silica has been obtained without drying said silica to a solids content greater than 40% by weight; and providing a second fluid comprising an elastomer latex and said second fluid having a second fluid volumetric flow rate, and combining under continuous flow conditions the first fluid and the second fluid to form a semi-solid silica-containing continuous rubber phase mixture, and forming said semi-solid silica-containing continuous rubber phase mixture into said silica elastomer composite in a mixing chamber of a device, and recovering said silica elastomer composite having a silica content of from about 15 phr to about 180 phr.

2. The method of claim 1 , wherein said silica is precipitated silica and wherein the destabilized dispersion is prepared by:
(a) acidifying a solution of silicate to obtain an aqueous slurry of the precipitated silica; and
(b) filtering said aqueous slurry of the precipitated silica to obtain said precipitated silica in the form of a filter cake that has a water content of from about 60 wt % to about 90 wt % based on the weight of the filter cake.

3. A method for making a rubber compound comprising
blending the silica elastomer composite prepared from the method of claim 1 with other components to form the rubber compound, wherein said other components comprise at least one antioxidant.

4. The method of claim 1 , wherein said silica content of said silica elastomer composite is from about 35 phr to about 115 phr.

5. The method of claim 1 , wherein said silica content of said silica elastomer composite is from about 40 phr to about 115 phr.

6. The method of claim 1 , wherein said destabilized dispersion of silica comprises about 10 wt % to about 28 wt % silica.

7. The method of claim 1 , wherein said first fluid comprising said destabilized dispersion of silica has a zeta potential magnitude of less than 30 mV.

8. The method of claim 1 , said method further comprises adding a carbon black to said first fluid, wherein carbon black is present in said silica elastomer composite in an amount of from about 10 wt % to about 0.1 wt % based on total particulates present in said silica elastomer composite.

9. The method of claim 1 , wherein said elastomer latex is natural rubber latex.

10. The method of claim 9 , wherein said natural rubber latex is in the form of a field latex, latex concentrate, desludged latex, chemically modified latex, enzymatically modified latex, or any combinations thereof.

11. The method of claim 9 , wherein said natural rubber latex is in the form of an epoxidized natural rubber latex.

12. The method of claim 9 , wherein said natural rubber latex is in the form of a latex concentrate.

13. The method of claim 1 , further comprising mixing the silica elastomer composite with additional elastomer to form an elastomer composite blend.

14. A method for making a rubber compound comprising
blending the silica elastomer composite prepared from the method of claim 1 with other components to form the rubber compound, wherein said other components comprise at least one antioxidant, sulfur, polymer other than an elastomer latex, catalyst, extender oil, resin, coupling agent, one or more additional elastomer composite(s), or reinforcing filler, or any combinations thereof.

15. A method for making a rubber article selected from tires, moldings, mounts, liners, conveyors, seals, or jackets, comprising
(a) compounding the silica elastomer composite prepared from the method of claim 1 with other components to form a compound, and
(b) vulcanizing the compound to form said rubber article.

16. The method of claim 1 , wherein the method further comprises conducting one or more post processing steps after recovering the silica elastomer composite.

17. The method of claim 16 , wherein the post processing steps comprise at least one of:
(a) dewatering the silica elastomer composite to obtain a dewatered mixture;
(b) mixing or compounding the dewatered mixture to obtain a compounded silica elastomer composite;
(c) milling the compounded silica elastomer composite to obtain a milled silica elastomer composite;
(d) granulating or mixing the milled silica elastomer composite;
(e) baling the silica elastomer composite after the granulating or mixing to obtain a baled silica elastomer composite;
(f) extruding the silica elastomer composite;
(g) calendaring the silica elastomer composite; and/or
(h) optionally breaking apart the baled silica elastomer composite and mixing with further components.

18. The method of claim 16 , wherein the post processing steps comprise compressing the semi-solid silica-containing continuous rubber phase to remove from about 1 wt % to about 15 wt % of aqueous fluid contained therein.

19. The method of claim 1 , wherein the method further comprises the step of conducting one or more of the following with the semi-solid silica-containing continuous rubber phase:
(a) transferring the semi-solid silica-containing continuous rubber phase to a holding tank or container;
(b) heating the semi-solid silica-containing continuous rubber phase to reduce water content;
(c) subjecting the semi-solid silica-containing continuous rubber phase to an acid bath;
(d) mechanically working the semi-solid silica-containing continuous rubber phase to reduce water content.

20. The method of claim 1 , wherein said silica elastomer composite is a semi-solid silica-containing continuous rubber phase, and said method further comprising converting said semi-solid silica-containing continuous rubber phase to a solid silica-containing continuous rubber phase.

21. The method of claim 20 , wherein said semi-solid silica-containing continuous rubber phase is converted to said solid silica-containing continuous rubber phase by treatment with an aqueous fluid comprising at least one acid, or at least one salt, or a combination of at least one acid and at least one salt.

22. The method of claim 1 , wherein said second fluid comprises a blend of two or more different elastomer lattices.

23. The method of claim 1 , wherein said process further comprises providing one or more additional fluids and combining the one or more additional fluids with said first fluid flow and second fluid flow, wherein said one or more additional fluids comprise one or more elastomer latex fluids, and said additional fluids are the same as or different from said elastomer latex present in said second fluid flow.

Assignees

• Cabot Corp

Inventors

• Xiong Jincheng
• Green Martin C
• Williams William R
• Fomitchev Dmitry
• Adler Gerald D
• Mcdonald Duane G
• Grosz Ron
• Morris Michael D

Classifications

• C08L7/00

  Compositions of natural rubber · CPC title

• C08K3/36

  Silica · CPC title

• C08L9/10

  Latex (C08L9/04, C08L9/08 take precedence) · CPC title

• C08K2201/006

  Additives being defined by their surface area · CPC title

• C08J3/16

  by coagulating dispersions {(C08J3/122 takes precedence)} · CPC title