摘要:
A thermally self-cross-linkable ethylene/vinyl acetate copolymer consisting essentially of the following monomer units:A. from 5 to 50% by weight of ethylene,B. from 30 to 87% by weight of vinyl acetate,C. from 2 to 10% by weight of a copolymerizable compound containing an N-methylol group,D. from 5 to 20% by weight of an acryl compound selected from the group consisting of alkyl acrylate and alkyl methacrylate where alkyl has from 1 to 10 carbon atoms,E. from 0.5 to 3% by weight of a mono-olefinically-unsaturated carboxylic acid, andF. up to 1% by weight of a poly-olefinically-unsaturated monomer, and having a glass transition temperature of between -40.degree. and +10.degree. C; as well as the process for its preparation.
摘要:
The invention relates to a process for the preparation of polymers from polymerizable urethanes prepared by reacting isocyanates having at least two isocyanato groups with polyesters of the formula ##STR1## wherein R is alkylene having from 2 to 10 carbon atoms, A is an ethylenically-unsaturated radical, and n is an integer of from 1 to 100.
摘要:
A copolymer having good properties for use as a pressure-sensitive adhesive from an aqueous dispersion comprising:(a) from 10% to 30% by weight of ethylene units,(b) from 29% to 69% by weight of acrylic ester units,(c) from 20% to 55% by weight of vinyl acetate units,(d) from 0.2% to 8% by weight of (meth)acrylamide units, and(e) from 0 to 12% of other olefinically-unsaturated monomer units copolymerizable with the above,said copolymer having a glass transition temperature of from -20.degree. C. to -60.degree. C. and a K-value according to Fikentscher, measured in tetrahydrofuran, of from 50 to 180; as well as processes to make the same and aqueous dispersions of the same for use as pressure-sensitive adhesives.
摘要:
A process for the manufacture of vinyl chloride copolymers having a reduced content of free vinyl chloride comprising polymerizing a monomer mixture containing from 15% to 90% by weight of vinyl chloride under aqueous emulsion polymerization conditions with conventional post-polymerization, releasing the pressure, flushing the gas space above the copolymer dispersion free of monomer, cooling the copolymer dispersion to a temperature of from 10.degree. to 40.degree. C., adding a redox catalyst to the cooled dispersion consisting of from 0.002% to 0.5% by weight of the dispersion of an oil-soluble peroxy compound, and a water-soluble sulfur-containing reducing agent in a ratio of reducing agent to peroxy compound of 0.5 to 3 equivalents, allowing the dispersion to stand at a temperature of from 10.degree. to 40.degree. C. for a period of two hours to two days and recovering a copolymer dispersion having a vinyl chloride content of less than 50 ppm.
摘要:
Binders for strengthening textile fiber structures and based on aqueous, self-crosslinking vinyl ester dispersions having a reduced formaldehyde content or containing no formaldehyde. The low content of free formaldehyde in the dispersion is achieved by partial or complete substitution of the crosslinking comonomers containing N-methylol groups by vinylalkoxysilanes as crosslinking agents. Non-woven treated with these formaldehyde-free or low formaldehyde binder systems are distinguished by high strength values and excellent solvent resistance.
摘要:
Aqueous ethylene/vinyl chloride/vinyl alkanoate and/or alkyl acrylate copolymer dispersions having a non-uniform particle size distribution, in which one particle size distribution maximum is at 0.03 to 0.2.mu. and a second maximum is at 0.15 to 1.mu. and in which 5% to 60% by weight of the particles belong to the amount of particles having said second maximum, which are produced by free-radical polymerization at 0.degree. to 90.degree. C., while stirring, in the presence of emulsifiers which, in amounts of 0.5% to 15% by weight, calculated on the final solid resin, are not added until a polymerization conversion of 1% to 60% by weight of the total amount of monomer has been reached. The copolymer dispersions have solids contents of 20% to 70% by weight of copolymer comprising 20% to 92% by weight of vinyl chloride, 5% to 60% by weight of ethylene and 3% to 75% by weight of vinyl esters and/or acrylic acid esters, and, optionally, up to 15% by weight of other monomers copolymerizable with ethylene and vinyl chloride, said monomers being metered into the polymerization mixture together with the emulsifiers during the manufacturing process.
摘要:
Ester copolymers cross-linkable under acid, alkaline and heated conditions consisting essentially of a copolymerizate with from 75% to 99% by weight of vinyl and/or acrylic ester monomer units, from 0.2% to 15% by weight of olefinically-unsaturated halotriazine monomer units, from 0.2% to 10% by weight of mono-olefinically unsaturated monomer units containing free or protected N-methylol groups and, optionally, up to 10% by weight of other monomer units copolymerizable with ester monomer units.
摘要:
A hydrolysis-resistant, film-forming, aqueous dispersion of a copolymer consisting essentially of(a) from 5% to 50% by weight of ethylene units,(b) from 10% to 60% by weight of vinyl alkanoate units having from 1 to 14 carbon atoms in the alkanoate moiety,(c) from 20% to 70% by weight of vinyl chloride units, and(d) from 5% to 30% by weight of alkyl methylacrylate units having from 1 to 8 carbon atoms in the alkyl moiety; as well as the hydrolysis-resistant films produced on drying the above aqueous dispersion having a hydrolysis resistance in a 5.times. 5 cm film having a thickness of 0.1.+-. 0.02 mm, such that after storage for four days in a 25% aqueous sodium hydroxide solution, its weight loss is less than 10%.
摘要:
A process for the continuous manufacture of an aqueous ethylene/vinyl acetate copolymer dispersion which comprises continuously copolymerizing ethylene and vinyl acetate and optionally other .alpha.-olefinically unsaturated monomers, in an aqueous emulsion in the presence of an emulsifier and/or a protective colloid, and in the presence of a free-radical-forming redox catalyst system of a reducing agent and an oxidizing agent as well, optionally, as a heavy metal salt, and recovering said ethylene/vinyl acetate copolymer dispersion, characterized by (a) the presence of a molar excess of at least 3 times, preferably from 3 to 10 times, said reducing agent over said oxidizing agent dosed into the reaction medium and (b) adding the monomers continuously to the reaction mixture at such a rate that the concentration of unreacted monomers at no place in the reaction zone exceeds 15% by weight of the total weight of the reaction mixture.
摘要:
An improvement in the production of polyvinyl ester dispersions by polymerization of vinyl esters or copolymerization of vinyl esters with up to 40% by weight of oil-soluble, mono-olefinically-unsaturated monomers in an aqueous emulsion in the presence of water-soluble radical-forming polymerization catalysts, protective colloids and optionally emulsifiers and polymerization aids, the improvement comprising using carboxymethyl celluloses having a substitution degree of at least 10 as said protective colloids; as well as stable mixtures of the said polyvinyl ester dispersions and dextrin.