摘要:
A process for preparing an aqueous polymer dispersion by free-radically initiated polymerization of free-radically polymerizable compounds I with moderate solubility in water, whose disperse polymer particles contain not only compounds I but also compounds II with a very low solubility in water where a mixture consisting of a portion of the compounds I and consisting of the compounds II is used to produce an aqueous emulsion I with a droplet size .ltoreq.500 nm, and at least a portion of the aqueous emulsion I is supplied continuously to the polymerization vessel as a feed stream I, in the course of continuing free-radical polymerization, during which the continuous feed stream I is accompanied, at least some of the time, by a feed stream II consisting of another portion of the compounds I or of the aqueous emulsion II thereof with a droplet size .gtoreq.1000 nm.
摘要:
A paper coating slip comprising at least one inorganic pigment and, based on 100 parts by weight of the inorganic pigments, less than 40 parts by weight of organic polymers and less than 25 parts by weight of water or other solvents having a boiling point below 150° C. at 1 bar.
摘要:
A process for preparing an aqueous polymer dispersion by free-radical polymerization of compounds I and II whose individual solubility in water is very different by the miniemulsion polymerization technique, in which process the reaction mixture is agitated by an external circuit which leads from and back again to the reaction vessel and comprises at least one low-shear pump and at least one heat exchanger having an essentially laminar flow profile. The copolymers prepared in accordance with the invention can be produced in a good yield within short times and exhibit good performance properties.
摘要:
The invention relates to an apparatus for transporting polymer dispersions, said apparatus being capable of being driven by a drive and being designed as an impeller (28). It is possible for said impeller both to be surrounded by a housing and to protrude freely into the polymer dispersion contained in the reactor tank. A number of vanes (2) are mounted in the region of the hub (1) of the impeller (28) in such a way that pumping spaces (5, 25) on the front side (7) and rear side (8) of the impeller (28) are flowed through uniformly.
摘要:
The invention relates to a method for monitoring exothermic reactions in a reactor, in which one or more starting materials react exothermically to give at least one product, and at least one gas is present in the reactor during operation as intended or during a runaway, comprising the following process: A) measurement and storage of an initial temperature and an initial pressure in the reactor, B) calculation of the amount of products and starting materials present in the reactor from an energy balance, C) calculation of a maximum pressure raise that occurs on stepwise reaction of the amount of starting materials present, and D) calculation of a runaway pressure from the maximum pressure raise that occurs, calculated in step C), and the measured initial pressure stored in step A).
摘要:
The invention relates to alkylglycol alkoxylates and alkyldiglycol alkoxylates that are obtainable by alkoxylating C4-8 alkylglycols or diglycols with C2-5 alkoxides up to an average alkoxylation degree of 1 to 8, based on the C4-8alkylglycols or diglycols. The invention further relates to mixtures from C2-5 alkoxylates of C4-8 alkylgycols or -diglycols that have an average alkoxylation degree of 1 to 8 and tensides that have an interfacial tension of less than 45 mN/m at 20° C. when dissolved in an amount of 5 g/l of water, and/or to diyhdroxyalkins or derivatives thereof.
摘要:
Polymer systems having reversibly temperature-dependent radiation transmission which are crosslinked with radiation induction, a process for their production, and their use for reversibly temperature-dependent control of the radiation transmission of glazing systems and solar-energy devices.
摘要:
Aqueous dispersions which contain a synthetic polymer obtained by free radical polymerization and a rosin are prepared by a process in which an aqueous dispersion of the synthetic polymer obtained by free radical polymerization is mixed with an aqueous formulation of a rosin which contains from 0.1 to 0.5 mol, based on 100 g of rosin, of carboxyl groups.
摘要:
Gels for thermotropic layers, obtainable by irradiation of a mixture comprisinga) an uncrosslinked polymer,b) monomers capable of free-radical polymerization andc) water or an organic solvent or mixtures thereof, with high-energy light.