摘要:
The invention provide a class of water-processable polymerizable prepolymers which comprises (1) siloxane-containing monomeric units derived at least one siloxane containing monomer having one hydrophilic group or chain and/or polysiloxane-containing crosslinking units derived from at least one hydrophilized polysiloxane or chain-extended polysiloxane crosslinker; (2) hydrophilic monomeric units derived from one or more hydrophilic vinylic monomers; and (3) from about 0.05% to about 5% by weight of polymerizable units each having a pendant or terminal, ethylenically-unsaturated group and free of any polysiloxane segment. The prepolymer comprises from about 20% to about 50% by weight of silicone relative to the total weight of the prepolymer and has a high water solubility or dispersibility of at least about 5% by weight in water and suitable for making silicone hydrogel contact lenses.
摘要:
Propylene polymer composites containing modified clays and compatibilizing agents, more specifically hydrogenated tallow modified montmorillonite and maleic anhydride grafted propylene polymers, are provided. Concentrates or masterbatches used to prepare the composites are also described. The improved composites of the invention exhibit increased melt strength compared to the base resin and to composites similarly formulated using other types of modified clays. Moreover, the improved results are achievable at lower compatibilizer levels and lower ratios of compatibilizer to clay than has heretofore been considered practical.
摘要:
A process is disclosed for the solid phase preparation of doubly oriented synthetic polymeric material from an orientable amorphous but crystallizable or a semicrystalline thermoplastic polymeric workpiece comprising: (a) presenting the conditioned workpiece, at the entry mode of an opposing pair of solid rollers that are spaced apart a distance substantially less than the thickness of the workpiece; and (b) deforming the workpiece by compressive passage through the paired rollers at a nominal deformation ratios of at least 2 to 1. The deformation drawing is carried out between the glass transition temperature and the melting point of the polymeric material, by applying a draw tension insufficient to cause tensile failure of the workpiece.
摘要:
The present invention provides a soft touch soft touch thermoplastic olefin composition. The soft touch thermoplastic olefin composition comprises a polypropylene-ethylene copolymer and a cross-linked or uncross-linked ethylene-propylene thermoplastic elastomer. The thermoplastic elastomer is present in a sufficient amount that the soft touch thermoplastic olefin composition has a 1% flexural secant modulus from about from about 10,000 psi to about 80,000 psi.
摘要:
The instant invention is directed to a process for preparing peroxide modified polypropylene/polyethylene blends that have superior extrusion coating properties. More specifically, the peroxide modified PP/PE blends produced by the instant invention exhibit a pronounced viscosity upturn at low frequencies (about
摘要:
The invention provide a class of water-processable polymerizable prepolymers which comprises (1) siloxane-containing monomeric units derived at least one siloxane containing monomer having one hydrophilic group or chain and/or polysiloxane-containing crosslinking units derived from at least one hydrophilized polysiloxane or chain-extended polysiloxane crosslinker; (2) hydrophilic monomeric units derived from one or more hydrophilic vinylic monomers; and (3) from about 0.05% to about 5% by weight of polymerizable units each having a pendant or terminal, ethylenically-unsaturated group and free of any polysiloxane segment. The prepolymer comprises from about 20% to about 50% by weight of silicone relative to the total weight of the prepolymer and has a high water solubility or dispersibility of at least about 5% by weight in water and suitable for making silicone hydrogel contact lenses.
摘要:
Linear low density polyethylene compositions suitable for the production of films having improved breathability are provided. The compositions which are comprised of a linear low density polyethylene base resin, a functionalized polyolefin and a polyester polyol are melt blended under conditions of mixing and shear to increase their melt elasticity.
摘要:
A process for polymerizing ethylene is disclosed. The polymerization is performed in the presence of a Ziegler-Natta catalyst system in two slurry reaction zones. Most of the polyethylene (70-95 wt. %) is produced in one of the zones, while a smaller fraction is produced in the other zone. The ratio of the weight average molecular weight of the smaller fraction to that of the larger fraction is greater than 8:1. The resulting polyethylene blend, which should have both high melt strength and high extrudate swell, will be useful for blow-molding applications.
摘要:
A process for the solid phase preparation of doubly oriented synthetic polymeric material from an orientable amorphous but crystallizable or a semicrystalline thermoplastic polymeric workpiece comprising: (a) presenting the conditioned workpiece, at the entry mode of an opposing pair of solid rollers that are spaced apart a distance substantially less than the thickness of the workpiece; and (b) deforming the workpiece by compressive passage through the paired rollers at a nominal deformation ratios of at least 2 to 1. The deformation drawing is carried out between the glass transition temperature and the melting point of the polymeric material, by applying a draw tension insufficient to cause tensile failure of the workpiece.
摘要:
The invention provide a class of linear chain-extended polysiloxane crosslinkers which comprises two terminal ethylenically unsaturated groups, at least two polysiloxane segments, and dangling hydrophilic polymer chains each covalently attached to a divalent organic radical separating each pair of adjacent polysiloxane segments. The present invention is also related to a polymer comprising crosslinking units derived from chain-extended polysiloxane crosslinker of the invention and to ophthalmic lenses comprising such a polymer.