Solution compounding process for achieving uniform, fine particle size dispersion of curing agents
AssigneeThe Firestone Tire & Rubber Company
InventorsMario N. De Trano, William L. Hergenrother, Ralph A. Maglio, David M. Roggeman
Life of this patent
Estimating the term…
Abstract
Rubber curing agents such as quinoids are solution compounded to achieve a uniform or homogeneous distribution thereof in a rubber composition. The curing agents are initially solubilized in an organic polar solvent and then mixed with the rubber masterbatch solution. The solvent is then removed. A uniform fine distribution of the curing agent results in improved physical properties. The present invention is particularly suitable as a sealant composition for tires.
Claims20
A solution compounding process for forming a dry sealant composition, comprising the steps of:
- (A) adding at least one quinoid curing agent to a solubilizing organic polar solvent and forming a dissolved quinoid solution,
- (B) adding said dissolved quinoid curing agent solution to a rubber cement, and mixing and precipitating during mixing said curing agent in said cement so that a uniform fine dispersion of said curing agent is formed, and
- (C) removing the volatile solvent of said mixture to form the dry sealant component wherein the average particle size of said dispersed quinoid curing agent is less than 10 microns.
A sealant composition, comprising:
- a dry sealant component, said dry sealant containing from about 55 percent to about 90 percent by weight of at least one low molecular weight tackifier, from about 10 percent to about 45 percent by weight of at least one high molecular weight rubber polymer, said low molecular weight liquid tackifier having a number average molecular weight of from about 500 to about 5,000, and from about 0.2 to about 2.0 parts by weight per 100 parts by weight of said dry sealant component of a quinoid curing agent, said quinoid curing agent added as dissolved particles in a solubilizing organic polar solvent to a rubber cement comprising said sealant component dissolved in a hydrocarbon solvent with precipitation therein during mixing and the subsequent removal of the volatile solvent of the rubber cement so that said quinoid curing agent is finely and uniformly dispersed in said dry sealant component, said precipitated quinoid curing agent having an average particle size of 10 microns or less;
- a peroxide component, said peroxide component comprising an organic peroxide and optionally a polar accelerator, the amount of said organic peroxide being from about 0.5 to about 10.0 moles per mole of said quinoid curing agent;
- and
- optionally from about 0.1 to about 50 parts by weight of a reinforcing agent per 100 parts by weight of said dry sealant.
Dependencies are inferred from the claim text.