Process for the preparation of water-dilutable coating binders, and the use thereof
AssigneeVianova Resins GmbH
InventorsLaszlo Tulacs, Hans Hiden, Werner Wilfinger, Johann Luttenberger
Life of this patent
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Abstract
A process is disclosed for preparing water-dilutable enamel paint binders based on oligourethane-acrylate copolymers. A specific monomer mixture is polymerized in the presence of a water-insoluble oligourethane obtained by reacting an aliphatic ester diol with a diisocyanate. Water dilutability is achieved by using (meth)acrylic acid. These enamel paint binders are used in combination with cross-linking components and if required other enamel paint binders to formulate baking enamels.
Claims20
A process for the preparation of coating binders based on oligourethane-acrylate copolymers, which are dilutable in water following at least partial neutralization of the carboxyl groups, wherein:
- (A) a monomer mixture containing
- (Aa) from 40 to 70% by weight of alkyl (meth)acrylates whose alkyl radicals have 2 to 4 carbon atoms,
- (Ab) from 5 to 20% by weight of hydroxyalkyl (meth)acrylates whose alkylene radicals have 2 to 4 carbon atoms,
- (Ac) from 3 to 15% by weight of (meth)acrylic acid,
- (Ad) from 10 to 35% by weight of aromatic vinyl compounds, preferably styrene,
- the sum of the percentages for components (Aa) to (Ad) necessarily giving the number 100, and the components (Aa) to (Ad) being selected such that in theory a corresponding acrylate copolymer would have an acid number of from 30 to 90 mg of KOH/g, a hydroxyl number of from 30 to 50 mg of KOH/g and a glass transition temperature of from -5.degree. to +25.degree. C.,
- is copolymerized in a water-dilutable organic solvent in the presence of a free-radical polymerization initiator and in the presence of
- (B) a water-insoluble oligourethane which:
- has been obtained by the reaction of monomers consisting essentially of an aliphatic ester diol or of a mixture of such diols with diisocyanates:
- contains no free isocyanate groups;
- and has a hydroxyl number of from 110 to 150 mg of KOH/g, a nitrogen content of from 2.8 to 3.7% by weight and a molecular mass of from 750 to 1000,
- with the proviso that the proportion of component (B) in the end product (AB) is from 35 to 60% by weight and said end product has an acid number of from 15 to 45 mg of KOH/g, a hydroxyl number of from 75 to 110 mg of KOH/g and an intrinsic viscosity (1.5% strength in chloroform/20.degree. C.) of from 13.5 to 16.5 ml/g.
A process for the preparation of coating binders based on oligourethane-acrylate copolymers, which are dilutable in water following at least partial neutralization of the carboxyl groups, wherein:
- (A) a monomer mixture containing
- (Aa) from 40 to 70% by weight of alkyl (meth)acrylates whose alkyl radicals have 2 to 4 carbon atoms,
- (Ab) from 5 to 20% by weight of hydroxyalkyl (meth)acrylates whose alkylene radicals have 2 to 4 carbon atoms,
- (Ac) from 3 to 15% by weight of (meth)acrylic acid,
- (Ad) from 10 to 35% by weight of aromatic vinyl compounds, preferably styrene,
- the sum of the percentages for components (Aa) to (Ad) necessarily giving the number 100, and the components (Aa) to (Ad) being selected such that in theory a corresponding acrylate copolymer would have an acid number of from 30 to 90 mg of KOH/g, a hydroxyl number of from 30 to 50 mg of KOH/g and a glass transition temperature of from -5.degree. to +25.degree. C.,
- is copolymerized in a water-dilutable organic solvent in the presence of a free-radical polymerization initiator and in the presence of
- (B) a water-insoluble oligourethane which:
- has been obtained by the reaction of an aliphatic ester diol or of a mixture of such diols with diisocyanates;
- contains no free isocyanate groups;
- contains no polymerizable double bonds;
- and has a hydroxyl number of from 110 to 150 mg of KOH/g, a nitrogen content of from 2.8 to 3.7% by weight and a molecular mass of from 750 to 1000,
- with the proviso that the proportion of component (B) in the end product (AB) is from 35 to 60% by weight and said end product has an acid number of from 15 to 45 mg of KOH/g, a hydroxyl number of from 75 to 110 mg of KOH/g and an intrinsic viscosity (1.5% strength in chloroform/20.degree. C.) of from 13.5 to 16.5 ml/g.
Dependencies are inferred from the claim text.