公开(公告)号：US20240240065A1

公开(公告)日：2024-07-18

申请号：US18561719

申请日：2022-05-10

Applicant: Evonik Operations GmbH

Inventor： Markus Scharfenberg ,  Christine Trömer ,  Dominik Sturm ,  Michael Waldhaus

IPC: C09J151/00 ,  B65D65/42 ,  C08F220/18 ,  C08F265/06

CPC classification number: C09J151/003 ,  B65D65/42 ,  C08F220/1804 ,  C08F265/06

Abstract: The present invention is directed to an aqueous dispersion comprising particles comprising a first polymer phase and a second polymer phase, where the second polymer phase comprises from 2 to 10% by weight of units based on acids copolymerizable with methacrylates, based on the entirety of the two polymer phases, and wherein the particles have a particle size dso, determined as given in the description, of from 100 to 150 nm, and wherein the entirety of the polymers comprised in the particles comprise of from 49 to 65% by weight of units based on methyl methacrylate and/or butyl methacrylate, of from 22 to 33% by weight of units based on a C1-C4-alkyl ester of acrylic acid, of from 3 to 7% by weight of units based on a hydroxy-functional (meth)acrylate, of from 2 to 8% by weight of units based on (meth)acrylic acid, and of from 5 to 15% by weight of units based on styrene, based on the total weight of the polymers, to a process for preparing an aqueous dispersion comprising a first polymer phase and a second polymer phase, where the second polymer phase comprises of from 2 to 10% by weight of units based on acids copolymerizable with methacrylates, based on the entirety of the monomers used to prepare the two polymer phases, wherein the aqueous dispersion is produced by means of emulsion polymerization, where a first monomer mixture which leads to the first polymer phase is used as or charged together with an initial charge into a reactor and, after polymerization of the first monomer mixture, a second monomer mixture which leads to the second polymer phase is added to the reaction mixture and polymerized, characterized in that a chain-transfer agent is added to both monomer mixtures, and wherein the entirety of monomers used is composed of from 49 to 65% by weight of methyl methacrylate and n-butyl methacrylate, of from 22 to 33% by weight of n-butyl acrylate, of from 3 to 7% by weight of hydroxy-ethyl acrylate, of from 2 to 8% by weight of acrylic acid, and of from 5 to 15% by weight of units based on styrene, based on the total amount of monomers present in both monomer mixtures, and to the use of an aqueous dispersion according to the invention or obtained by a process according to the invention in a heat-sealing lacquer for the sealing of aluminum surfaces with respect to aluminum, polystyrene (PS), polylactide (PLA), or other polymer materials used in food packaging, and to a heat-sealing lacquer for the sealing of aluminum surfaces with respect to aluminum, polystyrene (PS), polylactide (PLA), or other polymer materials used in food packaging, comprising at least 50% by weight of the aqueous dispersion according to the invention or obtained by a process according to the invention.