Aqueous adhesive dispersions
View Patent ↗Aqueous polymer dispersions based on polychloroprene, a process for their preparation and their use in adhesive formulations. The aqueous polymer dispersion is obtained by a) preparing an aqueous polychloroprene dispersion with a gel content of 0.1 wt. %-30 wt. %, based on the polymer, prepared by polymerization at 0° C.-70° C. of chloroprene and, optionally, ethylenically unsaturated monomers which can be copolymerized with chloroprene and b) subsequently storing the dispersion at temperatures of from 50° C.-110° C. until the gel content has risen by at least 10 wt. % to 1-60 wt. %, based on the polymer.
1. An aqueous polymer dispersion, obtained by
a) preparing an aqueous polychloroprene dispersion with a gel content of 0.1 wt. %-30 wt. %, based on the polymer, prepared by polymerization of chloroprene in an aqueous emulsion at 10° C.-25° C. and at pH value of 10-14 and, optionally, ethylenically unsaturated monomers which can be copolymerized with chloroprene and
b) subsequently conditioning the dispersion at temperatures of from 50° C.-110° C. until the gel content has risen by at least 10 wt. % to 1-60 wt. %, based on the polymer,
wherein the aqueous polymer dispersion has a gel content of between 1-60 wt. % based on the polymer and a pH value of between 10-14 and wherein the aqueous dispersion does not have a significant drop in pH after storage for 7 days at 60° C.
2. Aqueous polymer dispersion according to claim 1 , characterized in that the polychloroprene dispersion has a particle diameter of 60 to 120 nm.
3. The aqueous polymer dispersion according to claim 1 , having a regulator content between 0 to 0.25 mmol, based on 100 g of monomer.
4. The aqueous polymer dispersion according to claim 1 , wherein the dispersion has a gel content of 0.5-5 wt. % before the conditioning.
5. The aqueous polymer dispersion according to claim 1 , wherein the conditioning of the dispersion takes place at 60° C. to 90° C.
6. The aqueous polymer dispersion according to claim 1 , wherein after the conditioning in b) the polychloroprene dispersion has a gel content of 5 to 30 wt. %.