Celanese International Corporation

Matthias Junk

Stephan Krieger

Thomas Fichtner

Harald Petri

Ulrich Desor

Kerstin Wenzel

Bernhard Momper

A biocide- and ammonia-free aqueous polymer dispersion is obtained by radically initiated multi-stage emulsion polymerization and comprising particles comprising at least a first polymer phase formed from a monomer composition I and a second polymer phase from a different monomer composition II. The first polymer phase has a glass transition temperature below 20&#xb0; C., and the second polymer phase has a glass transition temperature above 20&#xb0; C., both as determined by differential scanning calorimetry according to ISO 16805. The polymer dispersion further comprises at least one water-soluble alkali metal silicate, at least one water-soluble alkali metal or alkaline earth metal alkyl siliconate, or a mixture thereof and has a pH of 10.0 or higher.

Biocide- and ammonia-free polymer dispersions

A multistage emulsion polymerization process comprises polymerizing a first monomer composition comprising from 50 to 95 weight percent of vinyl acetate, from 5 to 40 weight percent of at least one vinyl ester of a Cto Cunsaturated carboxylic acid, and optionally up to 40 weight percent of ethylene, all based on the total weight of monomers in the first monomer composition, to produce a first stage polymer. A second monomer composition comprising 40 to 89.95 weight percent of at least one ester of methacrylic acid or a vinyl aromatic monomer, 10 to 59.95 weight percent of at least one ester of acrylic acid, and from 0.05 to 10 weight percent of at least one comonomer with acid functionality, based on the total weight of monomers in the second monomer composition, is then polymerized in the presence of the first stage polymer to produce a second stage polymer.

Polymer dispersions, their preparation and use

An aqueous polymer dispersion is produced by multistage emulsion polymerization, in which a monomer composition I comprising 19 to 29 wt % hard monomers and 64 to 74 wt % soft monomers is polymerized to produce a first polymer phase and then a monomer composition II comprising 65 to 95 wt % hard monomers and 5 to 35 wt % soft monomers is polymerized to produce a second polymer phase. Monomer composition I also comprises from 1 to 5 wt % of at least one monomer selected from ethylenically unsaturated sulfonic acids, phosphonic acids, phosphoric acids, carboxylic acids, carboxylic amides, carboxylic anhydrides and mixtures thereof and 1 to 7.5 wt % of ethylenically unsaturated monomers containing keto groups. The weight ratio of monomer composition I to monomer composition II ranges from 50:50 to 65:35 and the polymer dispersion also contains a water-soluble cross-linking component selected from polyfunctional carboxylic hydrazides and/or polyfunctional amines.

Aqueous polymer dispersions

An aqueous copolymer dispersion is formed by emulsion polymerization of a monomer mixture comprising (a) 20 to 80 wt. % of one or more (meth)acrylic acid esters A, whose homopolymer(s) have a T&#x3e;25&#xb0; C. and at least one has a biorenewable carbon content of at least 50 wt. % of the total carbon content of the ester; (b) 19 to 79 wt. % of one or more (meth)acrylic acid esters B whose homopolymer(s) have a T&#x3c;25&#xb0; C.; (c) 0.5 to 10 wt. % of at least one monomer selected from unsaturated sulfonic, phosphoric and phosphonic acids, and unsaturated carboxylic acids, anhydrides and amides thereof; (d) up to 10% by weight of one or more functional monomers selected from hydrolysable silane compounds, epoxy-containing compounds, ureido-containing compounds and carbonyl-containing compounds, and (e) less than 5 wt. % of one or more further monomers, wherein the total percentages of comonomers (a) to (e) equals 100%.

Waterborne acrylic dispersions with high biorenewable content

A polymer dispersion is produced by polymerization of at least two different ethylenically unsaturated monomers in at least first and second stages. The polymer produced in the first stage comprises 25 to 60% by weight of the total monomer composition and has a uniform glass transition temperature from &#x2212;30&#xb0; C. to 0&#xb0; C. The polymer produced in the second stage comprises 40 to 75% by weight of the total monomer composition and has a variable monomer composition such that the second stage polymer has a non-uniform glass transition temperature which varies between a first value from &#x2212;30&#xb0; to +10&#xb0; C. and second value of at least +70&#xb0; C. Any polymer produced in further polymerization stages comprises no more than 10% by weight of the total monomer composition and the glass transition temperature of the hypothetical uniform copolymer produced by the total monomer composition is in the range from 0&#xb0; C. to 25&#xb0; C.

Growing community of inventors

Alsbach-Hähnlein, Germany

Matthias Junk