摘要:
The present invention relates to a process for the preparation of carbonic acid esters of polyester-polyols by transesterifying the polyols with carbonic acid aryl esters at elevated temperatures under vacuum in the presence of a catalyst. The reaction conditions are controlled to avoid the formation of by-products and the chain extension of the polyester-polyols. The present invention is also concerned with the polyester carbonic acid esters so formed, their use in producing polycarbonate block copolymers and the copolymers so produced. The copolymers may be produced by transesterifying the polyester carbonic acid esters with bisphenols and subjecting the bis-hydroxyaryl carbonates so formed to normal polycarbonate synthesis such as interfacial or melt polycondensation.
摘要:
The invention relates to a process for the production of chemically uniform copolymers of acrylonitrile and vinyl chloride and, optionally, other copolymerizable ethylenically unsaturated compounds, by the method of emulsion polymerization in the presence of an anion active emulsifier and a non-ionic emulsifier.
摘要:
A process for identifying manufactured articles in which a marking agent such as a homo- or copolymer of polymerizable ethylenically unsatured monomers is applied to the articles. Said homo- or copolymer contains at least one group which can be split off to form a low molecular weight compound such as an amine or phenol, which can be converted into dyes, said dyes being used to identify the manufactured articles.
摘要:
Aqueous dispersions of copolymers and graft copolymers which are formed from ethylenically unsaturated perfluoroalkyl monomers and ethylenically unsaturated monomers from from perfluoroalkyl groups and which are prepared in the presence of emulsifiers containing cationic groups are used for imparting a water-repellent and oleo-repellent finish to textiles, leather and paper.
摘要:
The new (meth)acrylic acid derivatives containing urethane groups can be prepared by reaction of a (meth)acrylic acid ester with diisocyanates and subsequent reaction with polyols. The compounds can be used for dental materials.
摘要:
(Meth)-acrylic acid esters of the formula ##STR1## in which R.sup.1 and R.sup.2 are each independently hydrogen, chlorine, fluorine or a C.sub.1 - to C.sub.4 -alkyl radical andR.sup.3 and R.sup.4 are identical or different and represent the group ##STR2## wherein Y is a divalent bridge member from the group ##STR3## and Z is a straight-chain or branched hydrocarbon chain which has 2 to 10 carbon atoms, can optionally contain oxygen bridges and is optionally substituted by 1 to 4 acrylate or methacrylate radicals,whereinR.sup.5 represents hydrogen or methyl andR.sup.6 represents hydrogen, C.sub.1 -C.sub.6 - alkyl or phenyl,which are useful as dental materials.
摘要:
(Meth)-acrylic acid derivatives of tricyclodecanes of the formula ##STR1## in which R.sup.1 and R.sup.2 are identical or different and denote hydrogen, lower alkyl, lower alkoxy, halogen or trifluoromethyl and R.sup.3 and R.sup.4 are identical or different and represent the group ##STR2## wherein X denotes a divalent bridge member from the group ##STR3## and Y denotes a divalent bridge member from the group ##STR4## and wherein R.sup.5 represents hydrogen or methyl and R.sup.6 represents lower alkyl or phenyl, have been found. Dental compositions in which the present (meth)-acrylic acid derivatives of tricyclodecanes are used, exhibit considerably less polymerization shrinkage.
摘要:
Thermoplastic moulding compositions consisting of from 1 to 99% by weight of at least one cellulose ester or cellulose mixed ester, from 99 to 1% by weight of an aliphatic polyester or polyether containing carbonate groups and, optionally, standard auxiliaries and additives.
摘要:
The invention relates to a process for the continuous production of a chemically uniform copolymer comprising 15 to 50% by weight of acrylonitrile and from 85 to 50% by weight of vinyl chloride and, optionally, up to 4% by weight of at least one other copolymerized ethylenically unsaturated comonomer containing acid groups by emulsion polymerization, wherein the copolymerization reaction is carried out with a monomer ratio of acrylonitrile to vinyl chloride of from 0.02 to 0.5, in the presence of a redox catalyst and in an acidic medium.
摘要:
A process for the polymerization of methyl methacrylate or mixtures thereof with up to 25%, by weight, based on total monomer, of vinyl monomers copolymerizable therewith, wherein polymerization is carried out in the presence of from 0.01 to 10%, by weight, based on total monomer, of one or more enol ethers derived from aliphatic or cycloaliphatic aldehydes or ketones.