摘要:
Low oil swell, non sticky readily processable carboxylated nitrile rubber-thermoplastic polyurethane vulcanizate compositions have increased upper service temperature over comparable thermoplastic polyurethanes. The compositions of the present invention are made utilizing a processing aid, for example, maleated polyolefins and addition type curing agents such as bisoxazolines or bisimidazolines. The compositions generally contain thermoplastic polyurethane as a continuous phase with the carboxylated nitrile rubber being dispersed therein.
摘要:
A polar thermoplastic and acrylate or ethylene acrylate based polar rubbers form a useful thermoplastic vulcanizate when the rubber is selectively cured with curatives which do not affect the polar thermoplastic and do not generate volatile organics. Examples of thermoplastics include aromatic polyesters, polycarbonates, poly(phenylene oxide), or combinations thereof. Examples of curatives include compounds with a multifunctional oxazoline, oxazine or imidazoline, which can react with functional groups such as carboxylic acid groups on the rubber.
摘要:
Low oil swell, processable carboxylated nitrile rubber thermoplastic vulcanizate compositions having high melting points are made utilizing a processing aid, for example, maleated polyethylene, and addition type curing agents such as bisoxazolines or bisimidazolines. The compositions generally contain polar thermoplastic high melting point crystalline polymers such as polyester as a continuous phase with the carboxylated nitrile rubber being dispersed therein.
摘要:
Random thermoplastic ethylene copolymers can be used to increase the elongation to break and toughness of thermoplastic vulcanizates. Polypropylene is a preferred thermoplastic phase. The rubber can be olefinic rubbers. Random thermoplastic ethylene copolymers are different from Ziegler-Natta ethylene copolymers as the compositional heterogeneity of the copolymer is greater with Ziegler-Natta copolymers. This difference results in substantial differences in properties (elongation to break and toughness) between thermoplastic vulcanizates modified with random thermoplastic ethylene and those modified with Ziegler-Natta ethylene copolymers. An increase in elongation to break results in greater extensibility in the articles made from a thermoplastic vulcanizate.
摘要:
A thermoplastic vulcanizate composition containing a thermoplastic and a functionalized copolymer of para-alkylstyrene-isoolefin is free radically cured, as for example, with a peroxide to yield a product having low impurities and good clarity. The thermoplastic typically can be a polyolefin.
摘要:
In the preparation of thermoplastic elastomers by hydrosilylation crosslinking of the elastomeric component, the use of an elastomer containing a non-conjugated diene and having a Mooney viscosity within the MST range of 45 to 100 provides products with a high level of crosslinking and an improved combination of physical properties. This improvement is obtained even at low concentrations of hydrosilylation catalyst.
摘要:
Thermoplastic vulcanizate blends are prepared from a semi-crystalline polymer and a rubbery copolymer derived from copolymerizing at least one alpha-olefin monomer and at least one cyclic olefin copolymer. The rubbery copolymer also includes repeat units from at least one polyene monomer. The polyene monomer provides residual unsaturation for crosslinking of said rubbery copolymer. Crosslinking the rubbery copolymer of the blend generally reduces tension set, compression set and oil swell in aliphatic solvents. The cyclic olefin monomer reduces oil swell in aliphatic oils.
摘要:
Thermoplastic vulcanizates from semicrystalline polyolefins and blends of crosslinked rubbers are disclosed. The blends are a mixture of at least two rubbers. One rubber is a copolymer predominantly of C.sub.4 to C.sub.7 isomonoolefins (e.g. isobutylene), along with optional monomers of conjugated dienes and/or p-alkylstyrene. This copolymer is optionally halogenated. The second rubber is ethylene/propylene rubber, natural rubber or a rubber polymerized predominantly from a conjugated diene. Such rubbers include polybutadiene, nitrile rubber, butadiene-styrene copolymers or combinations thereof.
摘要:
Thermoplastic elastomeric compositions, comprising blends of olefin rubber and polyolefin resin in which the rubber is cured with phenolic curative, exhibit superior properties including improved compression set and oil resistance.
摘要:
Ethylene-vinyl acetate polymer is modified by reaction with a polyfunctional acrylate which improves the processing characteristics of the polymer. The cured modified polymers exhibit improved properties including lower hardness and greater dimensional stability.