Producing polychloroprene latices
View Patent ↗The novel process provides latices of homo- and copolymers of chloroprene and of one or more further copolymerizable monomers at a higher reaction rate and hence in an improved space-time yield. The latices obtained have a high gel content, distinctly lower levels of by-products, in particular of chloroprene dimer, than prior art products, and are useful, if appropriate in concentrated form, for a wide variety of applications.
1. A latex of a homo- or copolymer of chloroprene and if appropriate one or more further copolymerizable unsaturated monomers, prepared by proceeding from a starting temperature T s raising the polymerization temperature during the emulsion polymerization
a) by at least 3° C. above the starting temperature T s up to a conversion of 50% and subsequently
b) by at least 6° C. above the starting temperature T s up to a conversion of 90%,
wherein the homo- or copolymer has a gel content in toluene at 23° C. of greater than 60% by weight, based on the homo- or copolymer and wherein the latex has a chloroprene dimer content of less than 254 ppm.
2. The latex of a homo- or copolymer of chloroprene and if appropriate one or more further copolymerizable unsaturated monomers, according to claim 1 , wherein, the homo- or copolymer having a gel content in toluene at 23° C. of greater than 80% by weight, based on the homo- or copolymer.
3. A concentrated latex of a homo- or copolymer according to claim 1 or 2 .
4. A method of producing a waterborne disperse adhesive comprising mixing the polychloroprene latex according to claim 1 either as sole latex component or in admixture with other lattices with water and evaporating the water.
5. A method of producing molded foam articles comprising subjecting the polychloroprene latex according to claim 1 to foaming either as sole latex component or in admixture with other latices in a mold.
6. A method of producing bonded fibers, impregnated fabrics, enhanced bitumen or bituminous materials or dipped goods, comprising contacting the polychloroprene latex according to claim 1 either as sole latex component or in admixture with other lattices with fibers, fabrics, bitumen oder bituminous materials or goods.
7. Disperse adhesive based on a polychloroprene latex according to claim 1 .
8. Molded foam article based on a polychloroprene latex according claim 1 .
9. Fabrics impregnated with a polychloroprene latex according to claim 1 .
10. Fibers bonded with polychloroprene lattices according to claim 1 .
11. Bitumen or bituminous materials enhanced with a polychioroprene latex according to claim 1 .
12. Dipped goods based on a polychioroprene latex according to claim 1 .
13. A latex of a homo- or copolymer of chloroprene according to claim 1 wherein the chloroprene dimers comprise 6 structurally isomeric compounds.