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

Patent metadata

Field	Value
Publication number	US-9926413-B2
Application number	US-201715599899-A
Country	US
Kind code	B2
Filing date	May 19, 2017
Priority date	Jul 15, 2015
Publication date	Mar 27, 2018
Grant date	Mar 27, 2018

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:
(a) providing a continuous flow under pressure of at least a first fluid comprising a destabilized dispersion of silica in particulate form, and having a wt % of silica of from about 6 wt % to 35 wt % based on the weight of the first fluid, wherein said silica has been obtained without drying said silica to a solids content greater than 40% by weight; and
(b) providing a continuous flow of at least a second fluid comprising elastomer latex;
(c) providing volumetric flow of the first fluid relative to that of the second fluid to yield a silica content of about 15 phr to about 180 phr in the silica elastomer composite;
(d) combining the first fluid flow and the second fluid flow with a sufficiently energetic impact to distribute the silica within the elastomer latex to obtain a flow of a solid silica-containing rubber phase or semisolid silica-containing continuous rubber phase that is the silica elastomer composite.

2. The method of claim 1 , further comprising before step 1(a):
(a) acidifying a solution of silicate to obtain an aqueous slurry of precipitated silica; and
(b) filtering said aqueous slurry of precipitated silica to obtain 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, wherein said precipitated silica is said silica in particulate form.

3. The method of claim 1 , further comprising, before step 1(a):
(a) acidifying a solution of silicate to obtain an aqueous slurry of precipitated silica having an initial ionic concentration; and
(b) adjusting the initial ionic concentration of the aqueous slurry of precipitated silica to yield a destabilized dispersion of the precipitated silica having an ionic concentration of about 10 mM to about 160 mM, wherein said precipitated silica is said silica in particulate form.

4. The method of claim 1 , further comprising before step 1(a):
(a) acidifying a solution of silicate to obtain an aqueous slurry of precipitated silica;
(b) without drying the precipitated silica, adjusting the aqueous slurry of precipitated silica to a solids content of from about 6 wt % to about 35 wt %, to obtain a destabilized dispersion of the precipitated silica, wherein said precipitated silica is said silica in particulate form.

5. The method of claim 1 , further comprising before step 1(a):
(a) acidifying a solution of silicate to obtain an aqueous slurry of precipitated silica;
(b) recovering precipitated silica without forming a filter cake, wherein said precipitated silica is said silica in particulate form.

6. The method of claim 1 , further comprising before step 1(a):
(a) adding an aqueous silicate solution to an aqueous slurry of carbon black particles to form a reaction mixture;
(b) adjusting the reaction mixture pH to deposit silica onto the carbon black particles and yield an aqueous slurry of silica coated carbon black particles having an initial ionic concentration; and
(c) without drying the reaction mixture to a solids content of greater than 40 wt %, adjusting the aqueous slurry of the silica coated carbon black particles to a solids content of from about 6 wt % to about 35 wt %, wherein said silica coated carbon black particles is said silica in particulate form.

7. The method of claim 1 , said method further comprising subjecting particulate silica to mechanical processing, whereby a controlled silica particle size distribution is obtained prior to carrying out step 1(a).

8. The method of claim 1 , wherein said first fluid in step (a) further comprises at least one salt.

9. The method of claim 1 , wherein said first fluid in step (a) further comprises at least one acid.

10. The method of claim 1 , wherein said solid or semi-solid silica-containing continuous rubber phase comprises from about 40 wt % to about 95 wt % water or aqueous fluid.

11. The method of claim 1 , where the relative volumetric flows are at a volumetric flow ratio of first fluid to second fluid from 0.4:1 to 3.2:1.

12. The method of claim 1 , wherein said destabilized dispersion of silica comprises at least one acid, and wherein said elastomer latex present in said second fluid has an ammonia concentration of from about 0.3 wt % to about 0.7 wt % based on the weight of the elastomer latex, and a molar ratio of hydrogen ions in said acid in said first fluid to ammonia in said second fluid is at least 1:1.

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

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

15. 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.

16. The method of claim 1 , wherein said destabilized dispersion of silica includes at least one salt, wherein salt ion concentration in said destabilized dispersion is from about 10 mM to about 160 mM.

17. The method of claim 1 , wherein said destabilized dispersion of silica includes at least one acid, wherein acid concentration in said destabilized dispersion is from about 200 mM to about 1000 mM.

18. The method of claim 1 , wherein step (c) is carried out with the continuous flow of the first fluid at a velocity A and the continuous flow of the second fluid at a velocity B, and velocity A is at least 2 times faster than velocity B.

19. The method of claim 1 , said method further comprising destabilizing a dispersion of silica by lowering a pH of the dispersion of silica so as to form the destabilized dispersion of silica provided in step 1(a).

20. The method of claim 9 , wherein said acid comprises acetic acid, formic acid, citric acid, phosphoric acid, or sulfuric acid, or any combinations thereof.

21. The method of claim 8 , wherein said salt comprises at least one Group 1, 2, or 13 metal salt.

22. The method of claim 8 , wherein said salt comprises a calcium salt, magnesium salt, or aluminum salt, or a combination thereof.

23. The method of claim 1 , wherein said elastomer latex is natural rubber latex in the form of a field latex, latex concentrate, desludged latex, chemically modified latex, enzymatically modified latex, epoxidized natural rubber latex, or any combinations thereof.

24. A method for making a rubber compound comprising:
blending the silica elastomer composite prepared by the method of claim 1 with other components, 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.

25. 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 by the method of claim 1 with other components to form a compound, and
(b) vulcanizing the compound to form said rubber article.

26. The method of claim 1 , further comprising conducting one or more post processing steps after step (d), 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

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

• C08J3/16

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

• C08K3/36

  Silica · CPC title

• C08K9/02

  Ingredients treated with inorganic substances · CPC title

• C08J3/22 Primary

  using masterbatch techniques · CPC title

• C08K3/04 Primary

  Carbon · CPC title