A thermoplastic elastomer composition includes about 80 parts by weight of an ethylene propylene diene monomer (EPDM) including 5-ethylidene-2-norbornene (ENB) and polyethylene, about 30 parts by weight to about 70 parts by weight of polypropylene, about 20 parts by weight to about 40 parts by weight of a filler, and about 60 parts by weight to about 90 parts by weight of a plasticizer.

Hollow microparticles of polyvinyl chloride are disclosed, having low volumetric densities useful for reducing mass per unit volume of polymer or inorganic articles and apparatus having such microparticles compounded into thermoplastic or thermoset polymers. A double emulsion polymerization process is also disclosed as the process to produce the hollow microparticles.

Disclosed is the preparation of compatibilized thermoplastic vulcanizates with reduced crosslinked rubber dispersion sizes and dispersity. A cross-linkable ethylene-propylene-diene terpolymer with majority propylene (PEDM) is used to compatibilize a plastic and rubber blend of a polypropylene (PP) and an ethylene-propylene-diene terpolymer rubber, where the propylene content is less than 50 wt % (EPDM), in dynamic vulcanization and preparation of PP/EPDM thermoplastic vulcanizates. The resulting PP/EPDM thermoplastic vulcanizates typically exhibit a weight average equivalent dispersion diameter of less than 3 microns and a particle size polydispersity index (PSDI), or weight average over number average dispersion diameter, of less than 5. This reduction in crosslinked rubber dispersion size in a PP/EPDM TPV by using PEDM compatibilizers enhances the toughness of the vulcanizate product by raising both elongation to break and break stress.

This invention relates to a thermoplastic vulcanizate having excellent elongation comprising an isotactic polypropylene matrix phase in which a cross-linked ethylene-propylene-diene terpolymer (EPDM) is dispersed, the vulcanizate comprising the reaction product of: a) 35 to 55 wt % of an ethylene-propylene-diene terpolymer (EPDM); b) 10 to 40 wt % of isotactic polypropylene (iPP); c) 0.5 to 25 wt % of a propylene-ethylene-diene terpolymer (PEDM) compatibilizer, said compatibilizer having a heat of fusion of less than 2 J/g; and d) 0.015 to 0.03 wt % of curatives;
wherein the percentages of components (a) to (d) are based on the total weight of the mixture.

A tire which has improved mechanical properties comprises a rubber composition based on at least one diene elastomer, at least one thermoplastic polyurethane, and a crosslinking system; the composition does not comprise any reinforcing filler or comprises less than 25 parts by weight thereof per hundred parts by weight of elastomer, phr, the carbon black content in the composition being less than 20 phr.

Provided is a crosslinked polyolefin foam is made by crosslinking and foaming the composition, wherein a product of 25% compressive strength (kPa) and tensile strength (MPa) of the crosslinked polyolefin foam at normal temperature is 35 to 65.

Provided is a rubber crawler including a guide rubber that is reduced in heat generation and excellent in abrasion resistance and an inner peripheral rubber that is excellent in scratch resistance and abrasion resistance and having excellent adhesiveness between the guide rubber and the inner peripheral rubber. The rubber crawler of the present invention includes a guide rubber obtained by crosslinking a guide rubber composition and an inner peripheral rubber obtained by crosslinking an inner peripheral rubber composition, the guide rubber composition containing a rubber component (A) and a carbon black (B), the rubber component (A) containing a butadiene rubber and at least one selected from a natural rubber and isoprene rubber, and containing 50 to 80% by mass of the natural rubber and the isoprene rubber and 20 to 50% by mass of the butadiene rubber, the carbon black (B) containing a carbon black (B-1) having an N.sub.2SA of 60 to 125 m.sup.2/g and a DBP absorption of less than 130 mL/100 g and a carbon black (B-2) having an N.sub.2SA of less than 60 m.sup.2/g and a DBP absorption of 110 mL/100 g or more, and a total content of the carbon black (B-1) and the carbon black (B-2) is 25 to 65 parts by mass based on 100 parts by mass of the rubber component; the inner peripheral rubber composition containing a rubber component (a) and a carbon black (b), the rubber component (a) containing 60 to 100% by mass of SBR and 0 to 40% by mass of a diene-based rubber other than the styrene-butadiene rubber, and a carbon black in an amount of 50 to 70 parts by mass based on 100 parts by mass of the rubber component.

A highly fire-resistant expanded polymeric material for thermal insulation, acoustic insulation and/or fire barrier contains rubber, expandable graphite, at least one alkaline earth metal component selected from alkaline earth metal carbonates, alkaline earth metal hydroxides, hydrates of either, and combinations thereof, and a component containing silica or a silicate. The expanded polymeric material is preferably manufactured by a process including decomposition of a chemical blowing agent.

A composition for use in selective modification of a base material surface includes a polymer having, at an end of a main chain or a side chain thereof, a group including a first functional group capable of forming a bond with a metal, and a solvent.

Provided are a perfluoroelastomer composition containing a perfluoroelastomer, a peroxide crosslinking agent, a co-crosslinking agent that is a diolefin compound, and an organic pigment; and a sealing material containing a crosslinked product of the perfluoroelastomer composition.