This technology is available from Temarex Corporation.

THERMOPLASTIC VULCANIZATES

Title: THERMOPLASTIC RUBBERY COMPOSITIONS

Inventor(s): A. Y. Coran, F. Howard

Disclosure 298 U.S. Patent not yet issued

This invention relates to a method for developing a composition of matter employing ground waste or recycled(tire) rubber with a low-modulus (crystalline thermoplastic polyolefin resin) binder, wherein the composition exhibits useful physical properties and good economy.

Current art use of ground rubber particles has been limited because of the expense of treating the ground rubber with coatings or coupling agents, or by using other treatments for the ground rubber. The low cost advantage of the recycled vulcanized rubber particles can be lost by such treatments.

The cost of material resulting from this invention should be substantially less than that of competing materials.

In general, the present invention provides a method of recycling vulcanized rubber such as ground tire rubber (GTR) into particles, adding the ground rubber to a low-modulus binder to form a thermoplastic rubbery composition. The binder resin includes vulcanized rubber as well as crystalline thermoplastic polyolefin.

The ground vulcanized rubber can include ground tire rubber(GTR), ground scrap rubber, mold flash, rejected parts, etc. The binder rubber can be EPDM, natural rubber, butadiene rubber, styrene-butadiene rubber, butyl rubber, halo-butyl rubber, ethylene propylene rubber (EPM), polyisoprene, polychloroprene, polybutene copolymers, chlorosulfonated polyethylene, etc. The crystalline polyolefin resin can be polyethylene (HDPE,LDPE, LLDPE) and polypropylene, etc.

This invention yields (a) engineering materials, (b)compositions of matter that have low stiffness and yet are highly extensible, (c) thermoplastic soft rubbery composition, (d) thermoplastic rubbery composition having improved physical properties, (e) improved ultimate tensile strength with low hardness or modulus at 5 percent, and (f)withstands more stretching before breaking than does known compositions employing ground waste rubber and crystalline thermoplastic resin.

Thermoplastic vulcanizates of the present invention can be processed via extrusion, injection molding and compression molding techniques.

Thermoplastic vulcanizates of the present invention are useful for making a variety of articles such as hoses, gaskets, moldings, small off-road tires (e.g. lawn mowers),floor mats, and the like.

Binder I- crystalline polyethylene (control)

Binder II - binder of the present invention

A review of the data in the table above indicates that the composition including ground tire rubber and the binder according to the present invention demonstrate improved strength coupled with low stiffness, especially when compared with those compositions that simple employ polyethylene as a binder.

Thus, it should be evident that the compositions of the present invention are highly useful and an improvement over known thermoplastic rubbery compositions, especially those employing used or scrap tire rubber

Title: VULCANIZABLE ELASTOMERIC COMPOSITION AND THERMOPLASTIC VULCANIZATE EMPLOYING THE SAME

Inventor(s): A. Y. Coran, O. Chung

Disclosure 272 U.S. Patent not yet issued

This invention relates to vulcanizable elastomeric composition and a method of vulcanizing the same.The vulcanizable elastomeric composition contains an elastomer having a reactive amino group and a phenolic curing agent,the vulcanization being capable of occurring without the use of a catalyst.

These vulcanized TPE are commonly referred to as thermoplastic vulcanizates (TPV), which are commonly produced by dynamic vulcanization. Dynamic vulcanization refers to the process whereby rubber is vulcanized during its melt-mixing with molten non-crosslinking plastic.

In many applications it is undesirable to have catalysts present during the dynamic vulcanization or in the Vulcanizate itself.The presence of a catalyst is undesirable because it can catalyze undesirable reactions within the blend, particularly reactions with the non-vulcanizing thermoplastic employed.For example, certain metal halides have been known to cause transesterification when the non-vulcanizing polyesters or ester-ether block copolymers are used.Furthermore, some catalysts are corrosive and tend to degrade the thermoplastic ester polymer.

Therefore, this composition of matter and process addresses the need for a vulcanizable elastomeric composition which may be vulcanized in the absence of any Lewis-acid catalyst,zinc oxide, or an equivalent thereto, often referred to as activation catalysts.

TPVs of the present invention are both heat and oil resistant. As such, the TPVs can be used as gaskets, seals,bumpers, oil-well injection lines and equipment, compressor valves\vacuum tubing and seals, hydraulic and fuel hoses,wire cable insulation, lip seals, diaphragms, o-rings,coolant gaskets, and the like.