摘要:
Brine (an aqueous solution of alkali metal chlorine) which is electrolyzed according to the amalgamation process, generally contains small amounts of mercury. It has been found that these traces of mercury are entrained with the evaporated water in a considerable amount when applying evaporation cooling to the brine. In order to keep these losses as low as possible, a pH of from 7 to 9.0 and a redox potential more than 1391-6.66(pH)-5.94(pH).sup.2 but not more than 1100 mV (based on the potential of the hydrogen electrode) is adjusted by adding chlorine or alkali metal hypochlorite and optionally alkali metal hydroxide to the brine.
摘要:
Rubber mixtures prepared from at least one styrene/butadiene rubber gel and at least one rubber which contains double bonds and optionally further fillers and rubber auxiliary substances are in particular suitable for the preparation of vulcanizates having unusually high damping at temperatures of from -20 to +20.degree. C. as well as unusually low damping at temperatures of from 40 to 80.degree. C. The rubber mixtures may therefore be used, for example, to manufacture vehicle tires which grip in the wet and have low rolling resistance.
摘要:
2,7'-Dimethyl-1,1'-binaphthyl and a process for preparing 2,2'-dimethyl-1,1'-binaphthyl and 2,7'-dimethyl-1,1'-binaphthyl by electrochemically oxidatively dimerizing 2-methylnaphthalene in the presence of acetonitrile/water/electrolyte salt mixtures which additionally contain at least one further component which, is immiscible or only partially miscible with water, and rectifying the reaction mixture obtained under reduced pressure.
摘要:
ABS type thermoplastic moulding compounds obtainable by A) producing a rubber latex with an average particle diameter d.sub.50 of 30 to 160 nm and a gel content of 75 to 100 wt. % B) emulsion polymerization of an amount of butadiene and optionally up to 50 wt. % (with reference to the total amount of monomer in stage B) of a comonomer in the presence of the rubber obtained in stage A, such that a rubber latex (B) with an average particle diameter d.sub.50 =220 to 330 nm and a gel content of 25 to 70 wt. % is produced, C) emulsion polymerization of 40 to 95 parts by wt. of a mixture of styrene and acrylonitrile, which optionally contains up to 50 wt. % (with reference to the total amount of monomers used in stage C) of one or more comonomers, in the presence of 5 to 60 parts by wt. (with reference to the solids) of the rubber obtained in stage B by introducing the monomer in such a way that 55 to 90 wt. % of the monomers are added within the first half of the total monomer introduction time, and D) mixing the polymer obtained in stage C, preferably after first converting it into a powder, with at least one thermoplastic vinyl resin.
摘要:
40-50% by weight finely divided, stable, aqueous dispersions (particle size 0.1-0.15.mu.) of copolymers of copolymerized units of20-48% by weight of acrylonitrile which may be partially substituted by styrene,47,5-70,5% by weight of n-butyl acrylate,3,5-4,5% by weight of methacrylic acid, which may be substituted up to 50% by acrylic acid and0-5% by weight of N-methoxymethyl metharylamide.The dispersions are prepared by a special process characterized by a critical combination of known process steps. The dispersions are eminently suitable for use as binders in unpigmented or pigmented aqueous dispersion paints for metal, wood, plastics and mineral substrates.
摘要:
An azo di-isobutyric acid-(N,N'-hydroxyalkyl)-amidine corresponding to the formula (I): ##STR1## in which R and R', which may be the same or different, represent linear or branched alkylene radicals containing from 2 to 4 carbon atoms, andX represents R'-OH or H.They may be produced by reacting an azo-di-isobutyric acid iminoalkyl ether containing from 1 to 4 carbon atoms in the alkyl group with at least one mono-alkanolamine containing from 2 to 4 carbon atoms or with a mixture of at least one monoalkanolamine and at least one dialkanolamine each containing from 2 to 4 carbon atoms in an alkanol radical, the molar ratio of monoalkanolamines to dialkanolamines in the mixture amounting to substantially 1:1, in substantially equivalent quantitative ratios at a temperature in the range of from 0.degree. to 50.degree. C. The amidines may be used as polymerization initiators, as cross-linking agents and as blowing agents in the production of foams.
摘要:
Copolymers ofA 22 to 96 mol-% of styrene and/or .alpha.-methyl styrene,B 0 to 78 mol-% of at least one monoolefinically unsaturated monomer containing nitrile groups, andC 0 to 50 mol-% of at least one monoolefinically unsaturated monomer different from A or B are obtained by continuous bulk polymerization in a homogeneous liquid phase, in several process stages, in one or more different temperature ranges and in the presence of one or more initiators with different dissociation times in each temperature range and under pressures of from 1 to 20 bars.In first stage the monomers are copolymerized with backmixing up to a conversion of from 10 - 60 mol-% in an ideally mixed tank reactor and then after optionally additional addition of further parts of monomers copolymerization is continued with backmixing in a completely flooded, self-cleaning polymerization kneader up to a residual monomer content of from 10-50 mol-%.Residual monomers are continuously removed from the copolymer up to a content of less than 0.5% by weight based on the copolymer.The process according to the invention provides uniform, compatible, homogeneous products which are free from gel-like particles and which combine improved transparency with greater dimensional stability under heat and better mechanical properties together with improved processibility.
摘要:
Elastic-thermoplastic graft polymers manufactured by radical emulsion polymerization of resin-forming vinyl monomers in the presence of rubber present in latex form with the use of a combination of a peroxide of formula (I) ##STR1## where R.sup.1 signifies alkyl, cycloalkyl and aryl groups with 4 to 20 carbon atoms, X the groups --COOH and --SO.sub.3 H as well as their alkali, alkaline-earth or ammonium salts, n an integer in the range from 1 to 6, A alkylene, cycloalkylene and arylene groups with 6 to 40 carbon atoms and a reducing agent as initiator system, a method for their manufacture and their use as moulding compositions.
摘要:
Elastic-thermoplastic graft polymers manufactured by radical emulsion polymerisation of resin-forming vinyl monomers in the presence of rubber present in latex form with the use of a combination of a peroxide of formula (I) ##STR1## where R.sup.1 signifies alkyl, cycloalkyl and aryl groups with 4 to 20 carbon atoms,X the groups --COOH and --SO.sub.3 H as well as their alkali, alkaline-earth or ammonium salts,n an integer in the range from 1 to 6,A alkylene, cycloalkylene and arylene groups with 6 to 40 carbon atomsand a reducing agent as initiator system, a method for their manufacture and their use as moulding compositions.
摘要:
New compounds corresponding to formula (I) ##STR1## and their use as emulsifiers for aqueous emulsions and, in the case of carboxylic acid derivatives, also as reactive groups for linking to biologically active substrates. New polymers synthesized from the emulsifiers and other monomers are also claimed.