An object is to provide a polyurethane elastomer excellent in strength and surface smoothness. To attain the object, a urethane composition including a certain prepolymer, a plasticizer and a crosslinking agent is provided.

The present invention relates to a biostable polyurethane or polyurea comprising: (a) a soft segment comprising a polysiloxane of the general formula (I); and (b) greater than O and less than 40 wt % of a hard segment which is a reaction product of a diisocyanate and a linear difunctional chain extender, processes for their preparation and their use in the manufacture of biomaterials, devices, articles or implants.

A method of manufacturing a polishing pad includes producing an urethane prepolymer having a viscosity of 20,000 cps (at 25 C.) to 40,000 cps (at 25 C.) by mixing a plurality of polymers, mixing the urethane prepolymer with an inert gas and a low-boiling blowing agent having a boiling point of 60 C. to 150 C., and manufacturing a polishing layer including porous pores by causing a mixture produced at the mixing to be subjected to gelation and curing in a predetermined cast.

The present invention relates to a polyurethane resin including, as constituent units, a diol (a1) having a number average molecular weight of 500 to 10,000, an organic diisocyanate (b), and a chain extender (a2). The total concentration of urethane groups and urea groups in the polyurethane resin is 1.25 to 2.50 mmol/g based on the weight of the polyurethane resin. Hard segment domains of the polyurethane resin have an average domain size of 20 to 30 nm as measured with an atomic force microscope.

The invention relates to a two-component polyurethane adhesive, in particular for laminating films, wherein the PU adhesive, based on the total weight of the laminating adhesive composition, (a) contains as resin component at least one NCO-terminated polyurethane pre-polymer having a content, based on the total weight of the resin component, of at least 40 wt % of diphenylmethanedi-isocyanate (MDI), wherein the MDI is 4,4-diphenylmethanediisocyanate or a mixture thereof with 2,4-diphenylmethanediisocyanate, and 2 to 20 wt % of polyglycol having a molecular weight Mw of 200 to <1000 g per mol, and (b) contains as hardener component a polyol mixture comprising 2, 3, or more different polyols and is free of polyesters. The invention further relates to the use of the adhesive for bonding films, to methods for producing composite films, and to composite films bonded with the adhesive described.

Partially crosslinked polyurethane polymers comprising diisocyanates and aliphatic hydrocarbon soft segments with a short-chain diol chain extender and a multifunctional amine and/or alcohol crosslinker to provide a polyurethane polymer with useful properties for the production of medical implant devices such as heart valves, are described. The polymers have an unexpected linear elastic region in a range from 5-100% and preferably between 10-35%. In some embodiments the polyurethanes are a thermally convertible gel formulation which may be converted to a liquid formulation by extended heating to render the polymer suitable for solvent processing techniques such as casting, spraying, spinning, etc. The invention also provides for living hinge polyurethane polymers which are thermally modifiable from a gel to a liquid and reaction injection moulded (RIM) polyurethanes with an enhanced flex life.

The present disclosure provides polymers prepared by a method comprising reacting a polymerization mixture comprising one or more types of diols, one or more types of polyols, and one or more types of isocyanates, wherein at least one type of the diols and/or at least one type of the polyols are phenols, wherein each of the phenols is independently a diol or polyol, wherein one or more instances of OH, NH.sub.2, and/or NH are aryl-bound. At least one instance of COH of at least one instance of the diols or polyols may react with NCO of the isocyanates to form COC(O)NH bonds. The polymers may be a thermoset under ambient conditions. At elevated temperatures, the polymers may undergo a transition from a cross-linked state to a lightly cross-linked or un-crosslinked state (e.g., at least in part because at least one instance of the COC(O)NH bonds may be cleaved (e.g., to form COH and NCO)). The transition may be reversable (e.g., by changing the temperature). The polymers of the present disclosure may be useful as hot melt adhesives. The present disclosure also provides compositions, kits, methods of preparation, methods of bonding, and methods of de-bonding.

This invention provides polyurethane foams containing a brominated flame retardant. Also provided are formulations and methods for preparing polyurethane foams containing a brominated flame retardant.

The present invention relates to a biostable polyurethane or polyurea comprising: (a) a soft segment comprising a polysiloxane of the general formula (I); and (b) greater than O and less than 40 wt % of a hard segment which is a reaction product of a diisocyanate and a linear difunctional chain extender, processes for their preparation and their use in the manufacture of biomaterials, devices, articles or implants.

##STR00001##

Provided are novel polyurethane elastic fibers having a high recovery stress, low hysteresis loss, and high heat resistance. The polyurethane elastic fibers of the present invention are polyurethane elastic fibers formed from a polyurethaneurea obtained from a copolyalkylene ether diol produced from different C.sub.2-10 alkylene ethers; a diisocyanate; and a diamine, the polyurethane elastic fibers being characterized in that the polyurethaneurea has a hard segment percentage of 14.0% to 25.0% as defined by formula (1): hard segment percentage (%)=(urea moiety number-average molecular weight)/{(urea moiety number-average molecular weight)+(moiety segment number-average molecular weight)}100 (formula (1)).