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.
摘要:
The invention includes dental materials based on organic plastics in paste form, comprising at least one phase consisting essentially of finely divided, crosslinked plastics which contain copolymerized ester(s) of methacrylic acid to the extent of at least 50% by weight, and the second phase consisting essentially of ester(s) of methacrylic acid to the extent of at least 50% by weight. The materials can be used for making prostheses, crowns, bridges, artificial teeth, dental fillings, etc.
摘要:
The invention relates to a homopolymer or copolymer of acrylonitrile which comprises from 0 to 30% by weight, incorporated by polymerization, of comonomer units which are free from ionic groups, said polymers having a K-value of from 50 to 100, a dye absorption capacity for cationic dyes of at least 0.5% by weight, a conductivity, measured in dimethylformamide solution, of at least 10.mu. Siemens, and from 0.2 to 1.5% by weight of sulphur fixed to said polymer as well as to a process for the production thereof.
摘要:
The invention provides dental materials which are opaque to X-rays and are based on organic plastics in paste form, which comprises (a) a polymerizable binder, (b) a crosslinked bead polymer and (c) an X-ray contrast medium. The materials can also contain as an additional component (d) a fine-particled inorganic filler which is not opaque to X-rays. The materials are useful, inter alia, for filing dental cavities.
摘要:
The invention relates to a process for the production of polyacrylonitrile or acrylonitrile copolymers, the polymerization being carried out at a temperature of from -40.degree. to +60.degree. C. optionally under pressure in an aliphatic chlorofluorine or fluorine substituted hydrocarbon containing up to 8 carbon atoms and having a boiling point of from -60.degree. to +50.degree. C. or in mixtures thereof having boiling ranges of from -60.degree. to +50.degree. C. and using a starter system comprising a hydroperoxide sulphur dioxide and an acid. The system may also contain aliphatic hydrocarbons in such quantities that a non-inflammable mixture is formed.
摘要:
A two-phase bead polymer having an average bead diameter of 10 to 120.mu., and comprising (A) 88 to 99.5% by weight of a polymer of polymerized units of at least one methacrylic acid ester containing from 1 to 10 carbon atoms in the aliphatic, saturated alcohol component, the methacrylic ester polymer, optionally, containing up to 30% by weight of copolymerized units of at least one monomer selected from acrylic acid esters containing from 1 to 10 carbon atoms in the aliphatic saturated alcohol component, hydroxyalkyl esters of methacrylic acid containing from 2 to 4 carbon atoms in the alkyl group, styrene, vinyl acetate, (meth)acrylamide, (meth)acrylic acid and/or itaconic acid, and (B) 0.5 to 12% by weight of a polyurethane.
摘要:
The invention relates to dry-spun modacrylic filaments with improved coloristic properties based on a polymer mixture, which comprises at least one acrylonitrile-vinyl chloride copolymer and a chlorine-containing copolymer containing sulphonic acid ester groups or sulphuric acid ester groups.
摘要:
This invention relates to a process for the production of light resistant and exhaust gas resistant PUH elastomer threads and films based on segmented polyurethane ureas which are based on diisocyanate mixtures of from 30 to 85 mol% of trans-1,4-cyclohexylene diisocyanate and from 70 to 15 mol% of other aliphatic or cycloaliphatic diisocyanates. The diisocyanates are first reacted with relatively high molecular weight dihydroxy compounds and optionally low molecular weight diols to form an isocyanate prepolymer which is then reacted with aliphatic diamines or diamine mixtures, preferably ethylene diamine, in highly polar solvents, optionally in the presence of salt type solubilizing agents such as lithium salts and preferably with the aid of aliphatic chain terminators, in particular those having a cycloaliphatic structure, to produce elastomer solutions which are stable under processing conditions. These solutions are spun in the conventional manner or dried to form films or coagulated to form sheet products.The invention also relates to the segmented polyurethane urea elastomers, in particular threads, obtainable by the new process.
摘要:
Water-soluble crosslinkable polymeric compounds which are obtainable by reaction of reaction products, containing halogenohydrin groups, of ammonia or mono- or polyamines and an epihalogenohydrin with inorganic bases and subsequent reaction of the resulting compounds containing epoxide groups with halogen-free sulphonic acids to give compounds containing sulphonic acid ester groups are used for imparting wet strength to paper.
摘要:
Dental fillings, coatings and teeth are formed of polymers and copolymers of a polyfunctional ester-urethane derivative of (meth)-acrylic acid of the formula ##STR1## in which A is a straight-chain or branched aliphatic radical which has 2 to 20 carbon atoms and optionally contains 1 to 3 oxygen bridges, an aromatic radical with 6 to 24 carbon atoms, an araliphatic radical with 7 to 26 carbon atoms or a cycloaliphatic radical with 6 to 26 carbon atoms,r denotes the number of chains starting from A and denotes a number from 2 to 6,R.sup.1 and R.sup.2 are identical and denote hydrogen or are different and denote hydrogen and methyl,n denotes a number from 0 to 5 independently for each chain starting from A,X stands for the group ##STR2## in which Y denotes a divalent (cyclo)aliphatic radical which has 2 to 15 carbon atoms and optionally contains ester, ether or urethane groups,Z denotes a divalent straight-chain or branched aliphatic hydrocarbon radical which has 3 to 15 carbon atoms and can optionally contain 1 to 3 oxygen bridges and can optionally be substituted by 1 to 4 additional (meth)-acrylate radicals andR.sup.3 denotes hydrogen or methyl independently for each chain starting from A.
摘要翻译:牙科填充物,涂料和牙齿由式(IMA)(I)的(甲基)丙烯酸的多官能酯 - 氨基甲酸酯衍生物的聚合物和共聚物形成,其中A是直链或支链脂族基团,其具有2 至20个碳原子,并且任选地含有1至3个氧桥,具有6至24个碳原子的芳族基团,具有7至26个碳原子的芳脂族基团或具有6至26个碳原子的脂环族基团,r表示链起始数 从A表示2至6的数,R1和R2相同并且表示氢或不同,表示氢和甲基,n表示从A开始独立地为0至5的数,X表示< IMAGE>其中Y表示具有2至15个碳原子并且任选地含有酯,醚或氨基甲酸酯基团的二价(环)脂族基团,Z表示具有3至15个碳原子的二价直链或支链脂族烃基, ca n任选地含有1至3个氧桥,并且可以任选地被1至4个另外的(甲基)丙烯酸酯基团取代,并且对于从A开始的每个链,R 3表示氢或甲基。