CZ34592A3 - Health harmless water-soluble coating system - Google Patents

Abstract

The system consists of 20 to 80 mass parts of a mix of two aqueous polymeric dispersions in a mass ratio of 1 : 3 to 3 : l, one of which contains a copolymer methylmethacrylate, n-butyl acrylate, methacrylamide and acrylic and/or methacrylate acid and the second a copolymer of methylmethacrylate, n-butyl methacrylate and acrylic and/or methacrylate acid, 3 to 15 weight parts of a defoamer-type additive, coalescent materials, conservation and biocidal media, corrosion inhibitors, a substance affecting rheological characteristics, UV stabilisers and surfactants, 2 to 80 weight parts water and possibly up to 40 parts matting-type ingredients, waxes, pigments, fillers and colours and up to 1.2 mass parts of alkaline additives for modifying pH.<IMAGE>

Description

Water-borne coating system

Technical field

The invention relates to a coating system, in particular for furniture, wall cladding, floors, ceilings and other products of wood and agglomerated veneered, non-veneered and laminated wood-based materials, such as fibreboard, particleboard and the like, and paper. The system modifies the surface of these products, is harmless to health and, besides the decorative and protective effect, limits the penetration of gaseous harmful substances, in particular formaldehyde. The system can also be used to coat other materials such as metals and plastics.

Background

So far, solvent-based lacquers such as nitrocellulose, acid-curable, epoxy, polyurethane, polyester and the like have been used to coat wood and agglomerated materials. · Nitrocellulose paints are one of the most widely used wood finishes. However, they contain a large amount of volatile organic solvents and their processing brings a considerable risk of fire. The so-called synthetic paints based on alkyd and epoxy resins also contain a certain amount of solvents. However, it requires a longer drying time and causes yellowing of the wood (Goldschmidt, A. et al., Glasurit - Handbuch Lacke und Farben, Vincentz Verlag Hanover 1984, ref. 397 484, ev. Pat. 407 796). As the so-called solvent-free varnishes, unsaturated polyester resin varnishes cured with either peroxide initiators with cobalt accelerators or UV radiation of mercury vapor lamps are used for the surface treatment of wood, in particular veneered particle board (Vachl, Chalupa: Wood 44 (4), p. 102). (1989) Kremer W .:

Farbe und Lack 94 (3), p. 205 (1989)). These lacquers contain volatile, polymerizable substances, most commonly Btyren, as diluents. The use of polyurethane coatings for furniture surface treatment is described by Riberi B.H .: Amer. Paint Coat. J. 74 (37), p. 36 (1990). These are two-component paints with a limited pot life. The combined nitrocellulose-based system and UV-cured polyurethane are described in European Patent Application Ser. U.S. Pat. 183 461. So far solvent solvents based on solutions of acrylic copolymers, which are described, for example, in U.S. Pat. AO 262 495. Due to the content of volatile organic solvents, their use is not suitable from an ecological point of view. Substantially more preferred are water-based paints based on acrylate dispersions, e.g. AO 274 806. The properties of the water-borne acrylic copolymer coating compositions are largely influenced by the copolymer structure, which is determined by the composition of the initial monomer mixture. However, coatings of conventional types of these coatings are not able to effectively prevent the penetration of harmful substances from the substrate.

SUMMARY OF THE INVENTION

The present invention is directed to a water-borne coating system suitable particularly for forming coatings having a barrier effect against the escape of gaseous pollutants from the substrate. The system consists of 20 to 80 wt. % by weight of a mixture of two 40-55% aqueous polymer dispersions in wt. a ratio of 1: 3 to 3: 1, of which one dispersion comprises a copolymer prepared from 40 to 62 wt. % methyl methacrylate; % n-butyl acrylate, 0.1 to 2 wt. % methacrylamide and 1 to 4 wt. acrylic and / or methacrylic acid. The second dispersion comprises a copolymer prepared from 30 to 70 wt. % methyl methacrylate, 30 to 70 wt. % n-butyl methacrylate and 1 to 6 wt. acrylic and / or methacrylic acid. The coating system further comprises 3 to 15 wt. parts of additives from the group comprising defoamers, coalescing agents, preservatives and biocides, corrosion inhibitors, substances affecting rheological properties. UV stabilizers and surfactants, 2 to 80 wt. parts of water and up to 40 wt. parts of additives from the group comprising matting agents, waxes, pigments, dyes and fillers and up to 1.2 wt. parts of basic pH adjusting additives.

The coating system of the present invention produces continuous, hard, glossy or matt coatings with very good mechanical properties. The coatings are physiologically safe and have a significant barrier elect for leakage of formaldehyde and other volatile substances from the substrate. Other advantages of the system are very good adhesion to all substrates including solvent-based paint films, overcoating with all common solvent and water-based paints, excellent abrasion resistance, easy sanding of the first coat after a relatively short drying time and the possibility of applying another coat after a very short drying time of the previous coat. The addition of the corrosion inhibitor has a positive effect in preventing immediate corrosion of any unprotected metal parts of the treated surface during application and coating drying. The slightly thixotropic character of the paint allows to achieve even deposition even on vertical surfaces. The application of this system significantly improves the working environment and reduces the risk of fire.

The coating film is applied by brush, roller, glazing, spraying or dipping with a break of between 1 to 3 hours depending on the ambient temperature, the substrate and the relative humidity. The higher the ambient and substrate temperature and the lower the relative humidity, the faster the paint dries. Prior to the first coating, it is expedient to free the treated surface from grease and mechanical impurities. After application, it is advisable to sand the dried coat with fine sandpaper, which easily removes the raised wood fiber and the next layer to achieve a perfect surface treatment of the substrate.

The coating system is designed especially for the surface treatment of wood products and agglomerated veneered, non-veneered and laminated wood-based materials such as particleboard, fibreboard, sawdust and shingle boards, plywood, blockboard, etc., used in wide tiling of tents and ceilings, parquet, molding, furniture parts, etc.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

Systems for treatment of lining of solid wood tents.

The cladding boards are treated with a coating system containing 20 wt. 50 parts by weight of the dispersion mixture. The mixture of dispersion I and dispersion II is 2: 1. Dispersion I contains a copolymer of 54% by weight. % methyl methacrylate, 42.9% wt. n-butyl acrylic, 0.1 X wt. % of methacrylamide and 3 X wt. acrylic acid. Dispersion II contains a copolymer of 30% by weight. methyl methacrylate, 68% wt. n-butyl methacrylate and 2 X wt. acrylic acid. Further, the coating composition contains 0.3 wt. part of defoamer based on mineral oils, 7 wt. parts by weight of propylene glycol monobutyl ether, 2 wt. parts by weight of an organic tin compound preservative, 1 wt. part of the hydroxyalkylcellulosic type, 2 wt. parts of polyethylene wax, 1 wt. part of aqueous ammonia with conc. 25 X wt., 40 wt. parts of water and 8 wt. parts of yellow micronized iron oxide.

The coating system is applied by dipping or brushing in two layers.

Example 2

System for veneered particle board treatment.

A coating system will be used to coat the abraded veneered chipboard? containing! 65 wt. parts by weight of a mixture of two dispersions with a dry matter content of 47.5% by weight ratio 1: 1.3. Dispersion I contains a copolymer of 55% by weight. of methyl methacrylate, 42% by weight. n-butyl acrylate, 2 X wt. methacrylamide and 1 X wt. acrylic acid. Dispersion II contains a copolymer of 46% by weight. % methyl methacrylate, 49.5% wt. % n-butyl methacrylate and 4.5% wt. methacrylic acid. Further, the coating composition contains 0.9 wt. parts of silicone defoamer, 8 wt. parts of butyldiglycol, 1.3 wt. 0.3 parts by weight of UV stabilizer; 0.1 parts by weight of sodium nitrite; 0.5 part by weight of sodium benzoate; 0.5 part by weight of acrylic thimble; parts of sodium hydroxide and 30 parts of water.

The coating system is applied by roller or screening. The surface treatment of the veneered particle board with this system reduces the formaldehyde emission from the particle board by up to 80%.

Example 3

Wallpaper surface treatment system.

It is applied by roller and consists of 25 masses. 40 parts by weight of a mixture of two dispersions having a dry weight of 40% by weight. Dispersion I and dispersion II are in wt. ratio 1: 0.33. Dispersion I contains a copolymer of 40% by weight. methyl methacrylate, 55 x wt. 2-wt. % of methacrylamide and 3 X wt. acrylic acid. Dispersion II contains a copolymer of 60% by weight. of methyl methacrylate, 39% by weight. n-butyl methacrylate and 1 X wt. acrylic acid. Further, the coating composition contains 0.1 wt. 3 parts by weight of paraffinic defoamer; parts by weight of butyl glycol acetate, 0.8 wt. % of sodium dihexylsulfonate and 0.2 wt. 0.2 parts by weight of benzisothiazolone-based biocidal composition; and 50 wt. parts of water.

Example 4

Parquet flooring system.

A coating system containing 60 wt.% Is applied to the sanded parquet friezes. 45 parts by weight of the dispersion mixture. Dispersion I and dispersion II are in wt. 1: 2 ratio. The dispersion contains a copolymer of 60% by weight. % methyl methacrylate, 37.5% wt. % n-butyl acrylate, 1.5% by weight. methacrylamide and 1 X wt. of methacrylic acid, dispersion II contains a copolymer of 35% by weight. methyl methacrylate, 62% wt.

% n-butyl methacrylate; acrylic acid. The jeété coating system contains 0.05 wt. mineral oil based defoamer, 13 wt. parts of butyl glycol, 1 wt. % of 1,2-benzisothiazolone, 0.95 wt. 1.1 parts by weight of a sodium salt of a copolymer of ethyl acrylate and acrylic acid; 25 parts by weight of ammonia, 6 wt. and 20 wt. parts of water.

The paint system is applied with airless spray gun.

Example 5 A toy coating system.

It is applied by spraying and consists of 75 wt. parts by weight of the dispersion mixture having a dry weight of 48% by weight. Dispersion I and dispersion II are in wt. ratio of 2: 1. Dispersion I contains a copolymer of 49% by weight. of methyl methacrylate, 49% by weight. % n-butyl acrylate, 0.5 wt. % of methacrylamide and 1.5 X wt. methacrylic acid. Dispersion II contains a copolymer of 35% by weight. methyl methacrylate, 62% wt. % n-butyl methacrylate; acrylic acid. Further, the paint comprises 0.15 wt. parts by weight of triethanolamine, 4 wt. parts of water, 0.1 wt. part of silicone defoamer, 8 wt. parts by weight of dipropylene glycol monomethyl ether; parts by weight of the sulfosuccinate surfactant, 0.4 wt. 0.1 part by weight of a boron compound-based preservative; 0.3 parts by weight of sodium nitrite; 10 parts by weight of acrylic copolymers; parts by weight of titanium dioxide, 4.4 wt. part of the pastal pigment paste.

Claims (2)

PATENTOVÉ NÁHOKY A water-borne coating system suitable in particular for the production of coatings having a barrier effect against the escape of gaseous pollutants from the substrate, characterized in that it consists of 20 to 80 wt. % by weight of a mixture of two 40-55% aqueous polymer dispersions in wt. a ratio of 1: 3 to 3: 1, of which one dispersion comprises a copolymer prepared from 40 to 62 wt. % methyl methacrylate, 32-55 wt. n-butyl acrylate; 2 X wt. % of methacrylamide and 1-4 wt. % of acrylic and / or methacrylic acid and the second dispersion comprises a copolymer prepared from 30 to 70 wt. % methyl methacrylate, 30 to 70 wt. % n-butyl methacrylate; % acrylic and / or methacrylic acid, 3 to 15 wt. parts of additives from the group comprising antifoams, coalescing agents, preservatives and biocides, corrosion inhibitors, rheolographic agents, and surfactants; parts by weight of ingredients of matting agents, waxes, pigments, fillers and dyes and up to 1.2 wt. parts of basic pH adjusting additives. UV stabilizers parts of water