Abstract: A process for preparing impact-resistant molding compositions by anionic polymerization of vinylaromatic monomers in the presence of a rubber, in a continuous-flow reactor cascade composed of at least two reactors, where the vinylaromatic monomers are fed in substreams to the reactors of the reactor cascade, and an anionic initiator and a rubber are fed at least to the first reactor, and where the reactor cascade is composed of back-mixing reactors.

Abstract: A process for the preparation of linear polymers or block copolymers of styrene by anionic polymerization comprises carrying out the chain termination with an n-alkyl glycidyl ether or a dialkyl ketone.

Abstract: A process for preparing impact-resistant molding compositions by anionic polymerization of vinylaromatic monomers in the presence of a rubber, in a continuous-flow reactor cascade composed of at least two reactors, where the vinylaromatic monomers are fed in substreams to the reactors of the reactor cascade, and an anionic initiator and a rubber are fed at least to the first reactor, and where the reactor cascade is composed of back-mixing reactors.

Abstract: The invention relates to an anionically polymerised, impact-resistant polystyrene with a dispersed plasticiser phase, comprising particles with capsule particle morphology and method for production thereof.

Abstract: A process for the preparation of linear polymers or block copolymers of styrene by anionic polymerization comprises carrying out the chain termination with an n-alkyl glycidyl ether or a dialkyl ketone.

Abstract: The invention relates to an anionically polymerised, impact-resistant polystyrene with a dispersed plasticiser phase, comprising particles with capsule particle morphology and method for production thereof.

Abstract: Block copolymers comprise at least two hard blocks S1 and S2 made from vinylaromatic monomers and, between these, at least one random soft block B/S made from vinylaromatic monomers and from dienes, where the proportion of the hard blocks is above 40% by weight, based on the total block copolymer.

Abstract: In a process for polymerizing dienes in a solvent comprising vinylaromatic monomers, the polymerization is carried out in the presence of a metal compound of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo or W as catalyst and a Lewis acid as cocatalyst and, if desired, an alkylating agent and, if desired, a regulator. This process can be used for preparing high-impact polystyrene, acrylonitrile-butadiene-styrene copolymers or methyl methacrylate-butadiene-styrene copolymers.

Abstract: The invention relates to a process for preparing an impact-modified plastic based on grafted crosslinked rubber particles, and also to an impact-modified plastic obtainable by the process. To prepare the impact-modified plastic, (a) particles of a crosslinked rubber are produced from a first monomer mixture which has a content of <50% by weight, preferably <5% by weight, particularly preferably <2% by weight, of diene compounds. The particles of the crosslinked rubber are (b) grafted with a second monomer or monomer mixture, with formation of a graft shell. Particles of the grafted crosslinked rubber are (c) added to a third monomer mixture, and the monomers of the third monomer mixture (d) are polymerized, with formation of a matrix. The process of the invention is simple to carry out and gives impact-modified plastics with very good mechanical properties, in particular with better resistance to weathering.

Abstract: The invention relates to a process for preparing an impact-modified plastic based on crosslinked rubber particles, where

Abstract: A process prepares impact-modified thermoplastic molding compositions which comprise a soft phase made from a rubber dispersed in a hard matrix composed of vinylaromatic monomers, where the hard matrix is prepared by anionic polymerization in the presence of a metal alkyl compound or a metal aryl compound of an element of the second or third main group, or of the second subgroup, of the Periodic Table.

Abstract: The invention relates to a process for preparing an impact-modified plastic based on grafted crosslinked rubber particles, and also to an impact-modified plastic obtainable by the process. To prepare the impact-modified plastic, (a) particles of a crosslinked rubber are produced from a first monomer mixture which has a content of at least 50% by weight, preferably at least 90% by weight, particularly preferably at least 98% by weight, of diene compounds. The particles of the crosslinked rubber are (b) grafted with a second monomer or monomer mixture, with formation of a graft shell. Particles of the grafted crosslinked rubber are (c) added to a third monomer mixture, and the monomers of the third monomer mixture (d) are polymerized, with formation of a matrix. The process of the invention is simple to carry out and gives impact-modified plastics with very good mechanical properties.

Abstract: A process for preparing a solution of high molecular weight polymers of conjugated dienes in a vinylaromatic hydrocarbon by anionic polymerization of the diene in the presence of an alkyllithium as catalyst and a process for preparing impact-modified polymers of vinylaromatic compounds is described. The first process comprises firstly polymerizing the diene in solution in an aromatic hydrocarbon which is free of ethylenic double bonds to a molecular weight below about 105, then adding a trialkylaluminum in a molar excess relative to the alkyllithium, diluting the solution obtained with the vinylaromatic compound and then coupling the polydiene with a polyepoxide or an alkyl (meth)acrylate to give a high molecular weight polymer. The solution obtained in this way is further processed to give an impact-modified polymer of a vinylaromatic hydrocarbon by polymerizing the solution prepared as described, if desired after addition of further amounts of a vinylaromatic compound, in a manner known per se.

Abstract: A process for the continuous anionic polymerization or copolymerization of styrene or diene monomers using an alkali metal alkyl compound as polymerization initiator is carried out in the presence of an alkyl- or arylmetal compound of an element which occurs in at least divalent form as rate regulator, preferably under non-isothermal conditions and without back-mixing in a tubular or tube-bundle reactor, preferably using an alkyl- or arylmetal compound A of the formula R1M1 and an alkyl- or arylmetal compound B of the formula R2nM2 in a molar ratio between B and A of from 0.1:1 to 500:1, where M1 is Li, Na or K; R1 is hydrogen, C1-C20-alkyl, C6-C20-aryl, or C7-C20-alkyl-substituted aryl; M2 is an n-valent element from group 2a, 2b or 3a of the Periodic Table; and R2 is hydrogen, halogen, C1-C20-alkyl or C6-C20-aryl; and a special anionic polymerization initiator containing no Lewis base.

Abstract: In a process for the homopolymerization of vinylaromatic monomers or the copolymerization of vinylaromatic monomers and dienes, the monomers are polymerized in the presence of at least one alkali metal organyl, at least one magnesium organyl and at least one aluminum organyl. The invention also provides an initiator composition for carrying out the process.

Abstract: The invention relates to a process for preparing an impact-modified plastic, where particles of a crosslinked rubber are produced from a first monomer mixture which has at least 50% by weight of conjugated diene compounds, the rubber particles are added to a second monomer mixture which has at least 85% by weight, preferably at least 90% by weight, in particular at least 98% by weight, of styrene, and the monomers of the second monomer mixture are polymerized. This process can prepare novel and improved impact-modified plastics. Novel impact-modified plastics are also described.

Abstract: An anionically polymerized impact-modified polystyrene has a yield stress of at least 24 MPa, measured at 23° C. to DIN 53455 and a hole impact strength of at least 11 kJ/m2, measured at 23° C. to DIN 53753, measured in each case on a specimen produced to ISO 3167. A preparation process is described.

Abstract: A process for preparing impact-modified styrene polymers (HIPS) omprises anionic polymerization of styrene in the presence of a rubber in one or more polymerization reactors in succession. The rubber is prepared in solution in an immediately upstream process. The heat of polymerization is utilized to remove the solvent for the rubber, this solvent having a boiling point lower than those of styrene and ethylbenzene, from at least one of the polymerization reactors via distillation with distillative cooling, and the solvent is reintroduced into the process of rubber preparation.

Abstract: A process for the reaction of an organic compound in the presence of a catalyst comprising, as active metal, ruthenium alone or together with at least one Group Ib, VIIb, or VIIIb metal in an amount of from 0.01 to 30 wt %, based on the total weight of the catalyst, applied to a support, wherein from 10 to 50% of the pore volume of the support comprises macropores having a pore diameter in the range of from 50 nm to 10,000 nm and from 50 to 90% of the pore volume of the support comprises mesopores having a pore diameter in the range of from 2 to 50 nm, the sum of said pore volumes being 100%, and said catalyst as such.

Abstract: Polymer mixtures comprise P1) from 1 to 85% by weight of an elastomeric block copolymer which has been built up from hard blocks S made from vinylaromatic monomers and from random soft blocks B/S made up from dienes and from vinylaromatic monomers, and which contains at least the block structure S-B/S-S, where the diene content is less than 50 percent by weight and the proportion of the soft phase formed from the blocks B/S is at least 60 percent by weight, based in each case on the entire block copolymer, P2) from 5 to 89% by weight of a block copolymer differing from P1) and made from vinylaromatic monomers and from dienes, P3) from 10 to 94% by weight of glass-clear or impact-modified polystyrene or mixtures thereof, and P4) from 0 to 84% by weight of other additives, where the total of components P1) to P4) is 100%.