摘要:
A process for the production of a pulverulent mixture consisting of(A) from 60 to 99 parts by weight of a brittle copolymer consisting of acrylonitrile and styrene, .alpha.-methylstyrene, methyl methacrylate or mixtures thereof, and(B) from 1 to 40 parts by weight of a flexible rubber-elastic polymer,by coagulating, in a first stage, a latex of (A) or a mixture of a latex of (A) and a part of a latex of (B), adding, in a second stage, the latex of (B) or the remaining part of the latex of (B), so that the desired quantity ratio of (A) to (B) is attained, and, in a third stage, separating the precipitated mixture of (A) and (B) from the aqueous phase, and drying it.
摘要:
Pourable rubber powders comprising particles having an average diameter of from 0.01 to 10 mm which contain, polymerized thereon, a shell of the polymer or copolymer of one or more vinyl monomers in a quantity of from 2 to 20% by weight, based on the rubber, and the core rubber is a latex polymer, the latex particles of which are composed of a core polymer and a sheath polymer, the core and sheath differing in their chemical composition and at least the sheath polymer being a diene or acrylate rubber having glass transition temperatures of below 0.degree. C., and a process for the preparation of such rubber powders, wherein a latex of an approximate rubber is completely broken with the formation of an aqueous suspension of the rubber; from 2 to 20% by weight, based on the rubber, of one or more vinyl monomers which form polymers having glass transition temperatures of above 25.degree. C. are then introduced into the suspension; and the monomer(s) is/are polymerized, optionally after adding a radical-forming catalyst.
摘要:
Graft copolymers having a diene rubber core surrounded by at least two different shells improve the impact strength under multi-axial stress of thermoplastic polyester moulding compositions.
摘要:
The present invention relates to a process for the preparation of bis-carbonic acid aryl esters of polyester-diols, lengthened via --OCOO-- groups, characterized in that polyester-diols with molecular weights Mn (number-average) of over 250, preferably over 600, are heated with carbonic acid bis-aryl esters at temperatures between about 100.degree. C. and 200.degree. C., preferably between about 110.degree. C. and 180.degree. C., in vacuo below about 35 mm Hg, preferably between about 25 and 1 mm Hg, in the presence of catalysts, less than one mol of carbonic acid bis-aryl ester being employed per OH group of the polyester-diol and the hydroxyaryl compounds formed being distilled off.The invention further relates to the bis-carbonic acid aryl esters of polyester-diols lengthened via --OCOO-- groups obtained according to the instant invention and their use for the preparation of polyester diol bis-diphenol carbonates, lengthened via carbonate groups, characterized in that polyester-diol bis-aryl carbonates are reacted with a diphenol at a temperature of from about 100.degree. to about 200.degree. C. in vacuo below about 35 mm Hg in the presence of a catalyst, wherein more than 1 mol of diphenol is employed per mol of carbonic acid aryl ester groups of the polyester-diol bis-aryl carbonate, lengthened via carbonate groups, and the resulting hydroxyaryl compound is distilled off.The invention finally relates to the polyester-diol bis-diphenol carbonates, lengthened via carbonate groups obtained according to the instant invention and their use for the preparation of polyester/polycarbonates and the polycarbonate/polyesters so prepared.
摘要:
This disclosure is concerned with a single step process for the production of diphenol terminated polycarbonates by the transesterification of diphenols, bis-aryl carbonates and polymeric diols with aliphatically bound terminal hydroxyl groups. These diols are selected from polyesters, polyethers, polythioethers and polyacetals. The transesterification is carried out at elevated temperatures under vacuum optionally in the presence of a catalyst with the ratios of the reactants being such as to avoid the retention of any terminal aliphatic hydroxyl groups or aryl carbonate groups.
摘要:
The present invention relates to the transesterification of the carbonic acid aryl esters obtainable according to German Published Patent Specification No. 2,650,533 with an excess of diphenol for the preparation of polyalkylene oxide-diol bis-diphenol carbonates lengthened via carbonate groups. The present invention also relates to the polyalkylene oxide-diol bis-diphenol carbonates, lengthened via carbonate groups, obtained according to the invention and their use for the preparation of polyether/polycarbonates. Finally, the present invention relates to the polyether/polycarbonates, obtained according to the invention, with an improved phase separation between the elastomeric segment and hard segment, which leads to better technological properties of the corresponding polycarbonate elastomers.
摘要:
The present invention relates to a process for the preparation of bis-carbonic acid monoaryl esters of polyester-diols, lengthened via --OCOO-- groups, characterized in that polyester-diols with molecular weights Mn (number-average) of over 250, preferably over 600, are heated with carbonic acid bis-aryl esters at temperatures between about 100.degree. C. and 200.degree. C., preferably between about 110.degree. C. and 180.degree. C., in vacuo below about 35 mm Hg, preferably between about 25 and 1 mm Hg, in the presence of catalysts, less than one mol of carbonic acid bis-aryl ester being employed per mol of OH group of the polyester-diol and the hydroxyaryl compounds formed being distilled off.The invention further relates to the bis-carbonic acid aryl esters of polyester-diols lengthened via --OCOO-- groups.
摘要:
This power circuit-breaker has at least one cylindrically constructed arcing chamber which is provided with a stationary contact, with a moving contact and with a quenching zone between the two contacts. A shaft of the moving contact is permanently connected to a blowout volume which is closed off on the stationary contact side by an insulating nozzle through which at least one flow channel passes. The arcing chamber has a first compression volume which is operatively connected to the blowout volume and to a second compression volume. It is intended to provide a power circuit-breaker in which the blowing-out of the arc with pure SF.sub.6 gas is made stronger. This is achieved by providing a moving auxiliary piston between the first compression volume and the second compression volume and by the auxiliary piston being connected to the moving contact via a direction-changing device.
摘要:
A transparent thermoplastic molding composition containing:A) 30 to 94% of a thermoplastic polycarbonates based on 2,2-bis-(4-hydroxyphenyl)-propane, andB) 6 to 70% of a resin-like vinyl polymer which contains structural units corresponding to formula (Ia) ##STR1## in which R.sup.1 is H or CH.sub.3,R.sup.2 is C.sub.1-4 alkylene andR.sup.3 is C.sub.1-4 alkyl,is disclosed. The composition is particularly suitable for the preparation of optical storage media.
摘要:
An improved process for the preparation of .alpha.-methylstyrene polymers by aqueous emulsion polymerization in which a styrene monomer mixture is first polymerized in a quantity of from 0.5 to 8% by weight of the total quantity of monomers and thereafter an .alpha.-methylstyrene monomer mixture is polymerized batchwise or semi-continuously.