Abstract:
Disclosed is a method for producing a thermoplastic ABS molding compound. According to said method, the thermoplastic copolymer A is produced from acrylonitrile and styrene by means of bulk polymerization or solution polymerization, while graft copolymer B, which is composed of a graft base (B1) and a graft shell (B2), is produced by means of emulsion polymerization using a redox initiator system, whereupon the thermoplastic copolymer A, graft copolymer B, and additional optional components K and/or additional thermoplastic polymers (TP) are mixed.
Abstract:
SUBSTANCE MIXTURES COMPRISING (A) VINYL-CONTAINING COMPOUNDS, (B) AN ACTIVE AMOUNT OF A MIXTURE INHIBITING THE PREMATURE POLYMERIZATION OF THE VINYL-CONTAINING COMPOUNDS, COMPRISING (i) AT LEAST ONE N-OXYL COMPOUND OF A SECONDARY AMINE WHICH CARRIES NO HYDROGEN ATOMS ON THE &Agr;-C ATOMS, AND (ii) AT LEAST ONE IRON COMPOUND, (C) IF APPROPRIATE NITRO COMPOUNDS, AND (D) IF APPROPRIATE COSTABILIZERS, A PROCESS FOR INHIBITING THE PREMATURE POLYMERIZATION OF VINYL-CONTAINING COMPOUNDS (A) AND THE USE OF MIXTURE (B), IF APPROPRIATE AS A MIXTURE WITH NITRO COMPOUNDS (C) AND/OR COSTABILIZERS (D), FOR INHIBITING THE PREMATURE POLYMERIZATION OF FREE RADICAL POLYMERIZABLE COMPOUNDS AND FOR STABILIZING ORGANIC MATERIALS AGAINST THE DAMAGING ACTION OF FREE RADICALS.
Abstract:
A process for preventing undesired polymerization is conducted by maintaining an effective concentration of a stabilizer which comprises N-oxyl radicals in a mixture containing ethylenically unsaturated compounds, wherein(i) an electronic signal which correlates with the concentration of the N-oxyl radicals in the mixture is obtained periodically or continuously,(ii) the electronic signal is compared with a reference value, and(iii) addition of a stabilizer to the mixture is controlled according to the comparison (ii).The signal is preferably obtained by ESR measurement. The process permits efficient use of the stabilizer.
Abstract:
A method (M1) for the anionic polymerisation of styrene monomers or styrene and diene monomers in which at least one N-oxyl compound (I) is added to the monomers before or during polymerisation. An Independent claim is also included for a method (M2) for the production of high-impact polystyrene comprising a rubber phase based on styrene and diene monomers and a hard matrix based on styrene monomers, by (a) anionic polymerisation of the rubber phase with addition of (I) as above and (b) anionic or radical polymerisation of the hard matrix.
Abstract:
The invention relates to a method for the continuous recovery of styrene from a mixture containing same, by distillation of the mixture in a cascade of n distillation columns. According to said method, (i) an inflow containing a stabilizer system is fed into the first column and/or is placed into at least one of the distillation columns positioned upstream of the nth distillation column, whereby said stabilizer system comprises N-oxyl radicals; (ii) in the bottom of the nth distillation column a high-boiling fraction containing the stabilizer system and boiling at a higher temperature than styrene is concentrated; (iii) a partial flow of the high-boiling fraction is recycled and placed into at least one distillation column positioned upstream of the nth distillation column; and (iv) the remainder of the high-boiling fraction is withdrawn from the process.
Abstract:
A mixture comprises: (A) a vinyl compound, together with (B) a nitroxyl compound of a secondary amine free of H atoms at the alpha -carbon; (C) a retarder; (D) O2; and optionally (E) a transition metal compound; and (F) a co-stabiliser.
Abstract:
- 20 - O.Z. 0050/37072 A thermoplastic molding material consists of a polycarbonate A and a graft copolymer B, the latter consisting of an elastomer (rubber) b1) and a shell b2) grafted onto the elastomer. The elastomer b1) contains, as copolymerized units, from 35 to 100% by weight of a diene from the group consisting of the conjugated dienes of 4 or 5 carbon atoms, and can contain, as copolymerized units, from 0 to 65% by weight of a monomer from the group consisting of the alkyl acrylates or alkyl methacrylates, where alkyl is of 1 to 8 carbon atoms. The shell b2) is obtained in a conventional manner by successive polymerization of the monomers constituting the shell, in two process steps, in the presence of the elastomer b1); in a first process step, from 10 to 90% by weight of a mixture of a vinylaromatic hydrocarbon and one or more ethylenically unsaturated monomers which differ from the said hydrocarbon, in a weight ratio of from 90:10 to 60:40, are first incorporated as copolymerized units, followed by the polymerization of from 90 to 10% by weight of a monomer from the group consisting of the alkyl acrylates or of the alkyl methacrylates, where alkyl is of 1 to 8 carbon atoms. The molding material is used for the production of shaped articles.