A halogen-free low dielectric resin composition is provided. The halogen-free low dielectric resin composition comprises: (A) a resin system, which includes: (a1) a polyphenylene ether resin with unsaturated functional groups, and (a2) a polyfunctional vinyl aromatic copolymer; and (B) an allyl cyclophosphazene compound represented by the following formula (I): ##STR00001## in formula (I), t is an integer ranging from 2 to 6,
wherein, the polyfunctional vinyl aromatic copolymer (a2) is prepared by copolymerizing one or more divinyl aromatic compounds and one or more monovinyl aromatic compounds.

Disclosed is the preparation of thermoplastic vulcanizates with reduced crosslinked rubber dispersion sizes and dispersity. The thermoplastic vulcanizates include a polypropylene matrix phase in which cross-linked rubber particles are dispersed. The thermoplastic vulcanizates include the reaction product of a mixture that includes at least 10 wt % of isotactic polypropylene at least 30 wt % of an amorphous propylene-ethylene-diene terpolymer containing at least 60 wt % propylene-derived units and less than or equal to 25 wt % of ethylene-derived units; at least 10 wt % of a diluent and at least 0.015 wt % of at least one curative. The mixture is preferably formed without adding an ethylene-propylene-diene terpolymer.

The present disclosure relates to synthetic polyisoprene elastomeric articles including: one or more cured blend compositions of pre-vulcanized synthetic polyisoprene particles and non-prevulcanized synthetic polyisoprene particles, wherein the pre-vulcanized synthetic polyisoprene particles and the non-prevulcanized synthetic polyisoprene particles are bonded by mono-sulfidic and/or di-sulfidic, and poly-sulfidic crosslinks, wherein the poly-sulfidic crosslinks are present in an amount of 60 to 79 percent of the total amount of crosslinks in the cured blend composition. Methods of making synthetic polyisoprene elastomeric articles such as gloves or condoms is also disclosed.

The present disclosure relates to synthetic polyisoprene elastomeric articles including: one or more cured blend compositions of pre-vulcanized synthetic polyisoprene particles and non-prevulcanized synthetic polyisoprene particles, wherein the pre-vulcanized synthetic polyisoprene particles and the non-prevulcanized synthetic polyisoprene particles are bonded by mono-sulfidic and/or di-sulfidic, and poly-sulfidic crosslinks, wherein the poly-sulfidic crosslinks are present in an amount of 60 to 79 percent of the total amount of crosslinks in the cured blend composition. Methods of making synthetic polyisoprene elastomeric articles such as gloves or condoms is also disclosed.

The present invention provides a rubber composition capable of giving cured products excellent in durability and vibration insulating properties. The present invention also provides a cured product of the composition, and a rubber vibration insulator using the cured product. The rubber composition includes a solid rubber (A), a liquid diene rubber (B), a silane coupling agent (C), and silica (D) having a BET specific surface area of 15 to 250 m.sup.2/g.

The invention provides a peroxide crosslinkable rubber composition including a hydrogenated nitrile rubber that is enhanced in scorch stability without deterioration in superior characteristics of crosslinked products of the composition. The invention also provides a crosslinked product of such a rubber composition. The rubber composition includes 100 parts by mass of a hydrogenated nitrile rubber (A), 5 to 100 parts by mass of a filler (B), 1 to 10 parts by mass of an organic peroxide (C), and 1 to 20 parts by mass of a liquid diene rubber (D) having a polystyrene-equivalent weight average molecular weight of 3,000 to 120,000 as measured by gel permeation chromatography (GPC).

Use of twin screw extrusion to further enhance the uniformity of crosslinked rubber dispersion in thermoplastic vulcanizates (TPVs) to improve elastic properties of TPVs is disclosed. Most specifically, this invention employs intermeshing twin screw extruders to further homogenize dynamically vulcanized rubber dispersions in TPVs so that their particle size dispersion index (PSDI), or the ratio of weight average equivalent dispersion particle diameter to number average equivalent dispersion particle diameter, can be lowered to less than 1.6 or 1.57 with corresponding elastic property improvements by having lower hysteresis, higher elongation to break, and higher retractive force. TPV products having lower PSDI and improved elastic properties, and apparatus for conducting the disclosed method, are also provided.

A nitrile rubber composition including: a carboxyl group-containing nitrile rubber containing 5 to 30% by weight of an ,-ethylenically unsaturated nitrile monomer unit, 0.1 to 10% by weight of a carboxyl group-containing monomer unit, 15 to 60% by weight of an ,-ethylenically unsaturated monocarboxylic acid ester monomer unit, and 20 to 64.9% by weight of a conjugated diene monomer unit and having an iodine value of 120 or less; and a reactive silicone oil.

A method for selectively modifying a base material surface, includes applying a composition on a surface of a base material to form a coating film. The coating film is heated. The base material includes a surface layer which includes a first region including a metal. The composition includes a first polymer and a solvent. The first polymer includes 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 the metal. It is preferred that the base material further includes a second region comprising substantially only a non-metal, and the method further includes, after the heating, removing with a rinse agent a portion formed on the second region, of the coating film. The metal is preferably a constituent of a metal substance, an alloy, an oxide, an electrically conductive nitride or a silicide.

A coagent masterbatch comprising a semi-crystalline polyolefin carrier resin and an alkenyl-functional coagent. A peroxide curable formulation comprising the coagent masterbatch and a polyolefin compound. A method of making the masterbatch and formulation; a peroxide-cured polyolefin product prepared therefrom; a manufactured article comprising or made from the masterbatch, formulation, or product; and a method of using the manufactured article.