摘要:
Antistatic and/or electrically conductive thermoplastic polyurethanes contain carbon black whose surface area determined by the BET method is from 600 to 1200 m.sup.2 /g, have a dibutylphthalate absorption number of 300 to 450 cm.sup.3 /100 g, a pour density of less than 250 kg/m.sup.3, and an average particle size less than 50 nm.Incorporation of the carbon black into the thermoplastic polyurethane produced by the continuous sheet method takes place at temperatures under the primary melt peak for the crystalline rigid segments, measured by means of differential calorimetry, preferably in an extruder.The products are suitable for preparing films for flat heating elements, antistatic hoses, cables, and profiles.
摘要:
In order to prepare thermoplastic polyurethane elastomers(a) organic diisocyanate,(b) polyhydroxyl compounds with molecular weights of 500 to 8,000, and(c) chain extenders with molecular weights of 60 to 400 in the presence of(d) catalysts, and optionally(e) auxiliaries, and/or(f) additivesare reacted in two reaction stages at temperatures from 60.degree. C. to 250.degree. C. In the first reaction stage the components are continuously mixed, the reaction mixture is applied to a carrier, preferably a conveyor band of thermoplastic material, and is allowed to react at the reaction temperature until solidified. Subsequently, the solidified reaction mixture is melted in an extruder and the reaction is completed in the second reaction stage.
摘要:
Process for the manufacture of graft polymers from copolymers of ethylene with vinyl esters, acrylates or methacrylates by grafting an ethylenically unsaturated carboxylic acid thereto in the presence of a free-radical polymerization initiator. Homogeneous graft copolymers are obtained from which sheeting can be made. To this end, the unsaturated carboxylic acid is first caused to diffuse into the copolymer and the mixture is then extruded at temperatures above the crystallite melting point of the ethylene copolymer.
摘要:
A process for the preparation of finely divided polyolefin molding materials from 100 parts by weight of polyolefin and from 1 to 30 parts by weight of a conductive carbon black, with or without other additives, wherein the mixture of polyolefin powder and carbon black is compounded, in a first stage, until the crystallite melting point of the polyolefin is reached, and is then brought, in a second stage, to a temperature which is from 3.degree. to 40.degree. C. above the said crystallite melting point, after which the mixture is discharged from the mixer within from 0.5 to 30 seconds and is cooled within 120 seconds.
摘要:
Unsaturated carboxylic acids are grafted onto copolymers of ethylene and carboxylates. Carboxylic acid containing initiator is caused to diffuse into shaped elements of the copolymers, polymerization then being carried to completion by heating. The products exhibit no fish eyes and are highly suitable for sheet manufacture.
摘要:
A composite element which comprises an elastic, cellular top layer (A) and a rigid base layer (B) of thermoplastic polyurethanes, the polyurethane elastomer (B) of the base layer being prepared by reactingBa) 1 mol of at least one essentially linear, relatively high-molecular-weight polyesterol or polyetherol,Bb) from 6 to 15 mol of an organic diisocyanate, preferably 4,4'-diphenylmethane diisocyanate, andBc) from 5 to 14 mol of at least one alkanediol or dialkylene glycol,in the presence ofBd) from 0.05 to 0.3% by weight, based on the total weight of (Ba) to (Bc), of water, and, if desired,Be) a catalyst, andBf) assistants and/or additives, is used as a cushioned fitting for vehicles.
摘要:
The present invention deals with flexible elastic polyurethane films, efficaciously having a thickness from 0.3 to 3 mm, prepared by sintering powdered thermoplastic polyurethanes, having:(a) a melt index of from 50 to 350, measured at 190.degree. C. with a compression force of 21.6 kg, and(b) a Shore A hardness of from 80 to 98, preferably while using from 0.05 to 1 part by weight of powdered aluminum oxide and/or silica gel per 100 parts by weight of said thermoplastic polyurethane, utilizing a heated mold.The polyurethane films are preferably used for coating molded articles used in the interior of motor vehicles.
摘要:
Foams of mixtures of polyolefins and styrene polymers are produced by mixing the polymers with low-boiling expanding agents in the presence of a hydrogenated styrene/butadiene block polymer or a graft polymer of styrene on a polyolefin at temperatures above the softening point of the polymer mixture and under a pressure which prevents foaming of the mixture, followed by extrusion of the foamable mixture into a zone of lower pressure. The resulting foams are resistant to organic solvents.
摘要:
Filaments and fibers based on polypropylene or copolymers thereof having a content of from 10 to 90% by weight of bitumen and a process for their manufacture, in which a mixture based on polypropylene or copolymers thereof and containing from 10 to 90% by weight of bitumen is melt-spun and drawn. The filaments and fibers produced in the manner of the invention are suitable for the production of woven and non-woven fabrics for insulating purposes and carpet underlays.
摘要:
Process for the manufacture of shaped articles of a mixture of polystyrene and a copolymer of ethylene with vinyl ester, acrylate or methacrylate. To this end, the said copolymers having a content of from 3 to 40% by weight of unsaturated ester are reacted with monomeric styrene in aqueous suspension in the presence of free-radical polymerization initiators. Whereas a portion of the styrene used is directly grafted onto the ethylene copolymer, the remainder of the polymerized styrene is present in a finely divided state as a homopolymer beside or within the grafted ethylene copolymer. There are obtained homogeneous shaped articles having a styrene content of more than 50% by weight.