CS243903B1 - Coating mixture for coating of wood-free papers - Google Patents

Abstract

The invention provides for the preparation of N-hydroxymethyl- -3-dimethoxyphosphoryl propionamide which is the basis of the flame retardant preparation textiles. The process of the invention can be achieved high quality product expressed bound formaldehyde and stability non-flammable finishes even at multiple times repeated washing and cleaning of the fabric. The result is achieved by conducting the reaction dimethylphosphite with acrylamide and subsequent methylolation under specific conditions.

Description

The invention relates to a coating composition with improved properties in which a new type of special low viscosity copolymer dispersion is applied.

The coating composition for the production of graphic coated papers must show good processability in the coating machine. The theological properties at the highest possible solids content are decisive for the workability.

The decisive criterion is the quality of the coating obtained by using the coating composition from the point of view. accuracy of print reproduction, contrast of faireb scale and processability on high-speed printing machines.

Pigments (kaolin, calcium carbonate, s-atin white-b-a, titanium dioxide and others) are used to prepare the coating composition for wood-free coated papers, together with binders and aforementioned gloss enhancers, water resistance, whiteness and the like.

The binders may be of the natural nature (starch, casein, proteins, cellulose derivatives), synthetic (dispersions of macromolecular substances, polyvinyl alcohol), possibly co-mbinations, and both.

The presently dispersed n-α and butadiene-styrene latex dispersions are fasting, but have low light fastness, which results in a yellowing of the coating. In addition, butadiene-styrene latex coatings tend to β-retention when vigorously drying the inks by flame. Acrylate dispersions have a higher degree of light-stability, but are more expensive.

Other paper dispersion technology uses dispersions containing butadiene-based acrylonitrile copolymers. Acrylic copolymers are used in the manufacture of coated cartons.

These disadvantages are overcome by a coating composition consisting of 5 to 35% by weight of a primary alkyl ester of acrylic acid, preferably 25% by weight and 65 to 95% by weight of vinyl acetate, preferably 75% by weight, emulsified in a water medium containing 1 to 1%. 10% by weight of a mixture of alkylpolyglycol ether and sodium phosphate esters with alkyl polyglycol ethers as emulsifiers in the presence of sodium phosphate salts and 0.1-0.25% by weight of a copolymer of propylene oxide and ethylene oxide, based on the weight of the dispersion.

Example 1 wt. 20 parts by weight of kaolin and 20 wt. parts of satin white is dispersed in water in which 0.24 wt. % of sodium polyacrylate as dispersant and 0.1 wt. die sodium hydride to form a suitable pH. The pigment suspension prepared in this way is admixed with a starch binder solution containing 4 wt-%, bridge parts of modified starch and 0.5 wt. parts of the optical part of the j-as well as the p r ο-s of the class.

0.5 wt. part by weight of an organic antifoam additive and 0.3 part by weight of an organic defoamer diluted 1: 5 with water.

At the end of the additive, a copolymer-dispersion of the primary alkyl ester of acrylic acid and vinyl acetate is cautiously added in an amount of 14.36 parts by weight of solids. By adding water s-a, the absolute dry substance of the coating composition sets 57 per-c. weight.

Example 2 hm-o-t. parts by weight of titanium white are dispersed in water containing 0.016 wt. % of sodium polyacrylate and 0.005 wt. % of sodium hydroxide. To the titanium white dispersion, a quantity of suspension containing 60 wt. parts of kaolin. Of the calcium carbonate carrier, an amount of 15% by weight calcium carbonate suspension is added. parts of this pigment.

The procedure is as in Example 1. Example 3

The pigment suspension is prepared according to Example 2, with the p-portion of the calcium carbonate being increased to 20 µm. parts. A solution of polyvinyl alcohol, which contains 2.5 wt. % polyvinyl alcohol and 0.6 wt. part of the optical brightener. 0.3 wt. % of the waterproofing additive -a 0.25 wt. part of the defoamer diluted with water 1: 5.

A copolymer dispersion of a primary alkyl ester of acrylic acid and vinyl acetate in a mixture containing about 11 parts by weight of solids is admixed to the mixture thus prepared. The dry weight of the coating composition is adjusted to 58% by the addition of water.

Claims (1)

Coating composition for coating wood-free papers consisting of pigments, emulsifier, binder and synthetic copolymer dispersion, characterized in that the synthetic copolymer dispersion consists of 5 to 35% by weight of a primary alkyl ester of acrylic acid, preferably 25 pens, and 65 to 65 wt. 95% by weight of vinyl acetate, preferably 75% OF THE INVENTION by weight, emulsified in aqueous. medium containing 1 to 10% by weight of a mixture of alkyl polyglycol ether and sodium phosphoric acid esters with alkyl polyglycol ethers as emulsifiers in the presence of sodium phosphorphonic acid salts and 0.1 to 0.25% by weight of a copolymer of propylene oxide and ethylene oxide, based on the weight of the dispersion.