CS273864B1 - Water-soluble epoxy coating composition - Google Patents

Abstract

The substance consists of a resinous component, which is a mixture of low-molecular epoxy resin and medium-molecular esterified dian-type epoxy resin, a polyamine hardener on a base of products from the reaction of specified polyamines with unsaturated adducts of fatty acids of vegetable oils, maleic anhydride and phenol formaldehyde condensates, from a mixture of water immiscible or limited miscible organic solvents and water miscible solvents, water and possibly additives.

Description

81

BACKGROUND OF THE INVENTION The invention relates to two-component water-borne coatings comprising an epoxy resin binder.

Water-dilutable epoxy coatings are a major advance in terms of health and environmental performance when compared to the same base coatings used as solutions in organic solvents, most often in xylene, toluene, acetone, butanol, or mixtures thereof. In this case, the water-dilutable epoxy binder also comprises two components, i.e. the resin itself and the hardener. The resin component is usually represented by a low molecular weight epoxy resin of the dian type and, in order to reduce the viscosity of the resin and improve the flow of the prepared coating composition, it usually contains up to 30% by weight. reactive or inert diluents. The second binder component is a water-soluble polyaminoamide (Blade No. 909,494). However, its aqueous solutions are highly viscous and its water dilutability is limited. To reduce the viscosity, it is necessary to add undesirable organic diluents and, in addition, the coating systems formed are sensitive to carbon dioxide, which adversely affects the quality of the coating films. The problem of paint quality, consisting mainly of the coating of the surface layer, is solved by the addition of aromatic vinyl compounds (U.S. Pat. No. 3,449,278), monoglycidyl ethers (b. Pat. No. 1,242,783), phenol-formaldehyde condensates. 193,190), carboxylic copolymers based on conjugated dienes (U.S. Pat. No. 218,996) or methacrylic compounds (U.S. Pat. No. 218,997). Nevertheless, the viscosity of their aqueous solutions remains very high for the aminoamides thus modified, which impairs the pugmentation and filling process as well as the applicability of the coating systems. Low viscosity water soluble amino amides can be prepared by reacting unsaturated fatty acid adducts and unsaturated dicarboxylic acid anhydrides with phenol condensation products with aldehydes by reacting esterified unsaturated fatty acid adducts and unsaturated dicarboxylic acid anhydrides with condensation products of phenols with aldehydes products and reacting these products. certificate No. 242 293). The polyaminoamides thus prepared form solutions with water whose viscosity is substantially lower when compared to other types of water-soluble amino amides at the same dry matter and the same amine number. Although they are considerably more reactive, their major drawbacks are the low stability of the aqueous emulsions formed and the short lifetime of the emulsions, which, moreover, are difficult to dilute with additional water and difficult to apply. The applied film has an unsteady surface, is cloudy and after curing it is relatively brittle with low impact resistance.

These drawbacks are largely overcome by the present invention, which are based on water-based epoxy paints based on modified epoxy resins, inert organic solvents, low molecular weight polyaminoamide hardeners, water and optionally additives. SUMMARY OF THE INVENTION The present invention is based on a new composition of paints, which mainly comprises a binder consisting of 100 wt. parts of the resin component consisting of a mixture of 1 to 99 wt. parts of dian-type epoxy resin of mol. 380 to 500 and 1 to 50 wt. parts of dian-type epoxy resin of mol. 700 to 10,000 esterified 0.5 to 40 wt. % of fatty acids of vegetable oils and from 80 to 150 wt. parts by weight of polyaminoamide hardener based on reaction products of polyamines having a carbon number of 2 to 20 and nitrogen atoms of 2 to 10 with unsaturated fatty acid adducts of vegetable oils, maleic anhydride and phenol-formaldehyde condensates in wt. ratio of polyamines and adducts 1 and 0.1 to 1.2. In addition to the binder, these coatings contain from 1 to 50% by weight. parts by weight of the organic solvent mixture consisting of 2 to 60 wt. % of at least one water-immiscible or sparingly miscible solvent, in particular from the group consisting of aromatic hydrocarbons and aliphatic ketones, and 40 to 98 wt. % of at least one water-miscible solvent of the group of aliphatic linear monovalent alcohols having a carbon number of 4 to 8, furthermore 150 to 500 wt. parts of water and optionally up to 500 wt. parts of additives from the group comprising pigments, fillers, dyes, flow agents, biocides, defoamers, coalescents and viscosity regulators and pK.

CS 273864 Bl

The coatings of the present invention are stable under normal storage conditions for more than one year. They withstand, without changing the properties, lowered temperatures down to -25 ° C and elevated temperatures up to 60 ° C. They do not change even after exposure to intense mechanical stress and are sufficiently stable even when diluted with water. Partial esterification of the medium-molecular epoxy resin confers sufficient flexibility, even in large thicknesses, to cured coating films or sealant layers. The cured coating films are sufficiently hard and have good chemical and water resistance. A mixture of organic solvents, where one part is a water-immiscible or limited miscible solvent and the other part of a water-miscible solvent, significantly affects the quality of the paint or sealant surfaces. These surfaces are smooth, hard and free from visual defects.

Said coating compositions are most easily prepared by directly dispersing the powdered components, i.e. pigments and fillers, either in a low viscosity water-soluble polyamine amide or in a modified epoxy resin or both, and homogenizing the resulting mixture with the other additives. However, it is also possible to pre-prepare with a suitable homogeniser a pigment paste with a sufficient content of surfactants or other wettable substances, and to subsequently homogenize them with the other components of the paint. The presence of surfactants ensures sufficient stability not only of the pigment pastes themselves, but also of the resulting paints. Suitable pigments are, for example, iron and titanium oxides, lithopone, zinc-tetraoxychromate, zinc phosphate and a number of other anticorrosive and other pigments. powders such as sword or zinc and the like. Dyes and pigments of organic origin can also be used.

It is advantageous to apply these coatings to substrates which require sufficient flexibility of the cured coating layer. They can be applied by brush, spraying, dipping, pouring and rolling. The applied coatings are well bonded and dry to degree 1 in 3 to 10 h, to degree 5 in 24 h. After drying the coatings are water resistant, have excellent adhesion and good mechanical properties and can be easily overcoated with the same or other types of paints. They are especially suitable for surface treatment of concrete structures and plasters, metal structures and also for coating wood and chipboard or fiberboard materials.

The subject of the invention is exemplified by the following examples in which the stated coatings ratings correspond to the following valid CSN:

3050 - Production of test coatings

3052 - Determination of drying of paints

3061 - Measurement of coating thickness

3076 - Determination of hardness of coating films by pendulum apparatus

3063 - Determination of coating gloss

3079 - Determination of bending resistance of paint

3081 - Determination of resistance of paints by digging in an Erichsen apparatus

3085 - Determination of adhesion of coatings by grid test

Examples

The following esters, epoxy resins and aminoamide hardeners were used in the preparation of the coating compositions given in the following examples:

Ester A

They are prepared by reacting 500 wt. parts of epoxy resin of mol. weight 950 s 15 wt. parts of soybean oil fatty acids at 180 ° C to a melt acid number of 0 mg KOH / g. The resulting ester is dissolved at 90 ° C in a mixture of cylene and isopropanol (4: 1 solvent ratio by weight) to a 50% solution whose epoxy equivalent is 1050.

CS 273864 Bl

Ester B

They are prepared by reacting 500 wt. parts of epoxy resin of mol. weight 700 with 100 wt. parts of stearic acid under the same conditions as in the preparation of ester A. The ester obtained is diluted with a mixture of toluene with n-butanol and ethanol (in a solvent ratio of 3.5: 1: 0.5) to a 50% solution having an epoxy equivalent of 850 .

Ester C

They are prepared by reacting 500 wt. parts of epoxy resin of mol. weight 2,560 with 5 wt. The product was diluted at 120 ° C with a mixture of methyl ethyl ketone with butyl acetate and isopropanol (2: 2: 1 solvent ratio) to a 50% epoxy equivalent solution of 2700.

Epoxy resin AND Epoxy resin O mol. weight 380 SO wt. parts Ester A 15 Dec 11 Nonionic surfactant 5 , 1 II Epoxy resin 8 Epoxy resin 0 mol. weight 380 10 wt. parts Epoxy resin 0 mol. weight 450 70 II II Ester B 15 Dec II II Nonionic surfactant 5 11 11 Epoxy resin C Epoxy resin 0 mol. weight 380 50 wt. parts Ester C 45 11 Nonionic surfactant 5 11 II

Hardener A is an aminoamide resin prepared by reacting fatty acids of linseed oil and maleic anhydride with diethylenetriamine and phenolic novolak. The resin was applied in the form of a 50% aqueous solution having an amine number of 130 mg KOH / g.

Curing agent B is an aminoamide resin prepared by reacting the fatty acid of dehydrated castor oil and maleic anhydride with tetraethylenepentamine and further reacting the resulting product with cresol novolak in wt. 1: 1 ratio. It is used in the form of a 50% aqueous solution having an amine number of 180 mg KOH / g.

Example 1

Primer

Epoxy resin

Hardener A

Water

100 wt. of parts 120

150

It is prepared by first adding water to the aminoamide resin (hardener) with stirring, and then mixing the epoxy resin. The obtained mass is used for penetration of absorbent substrates.

CS 273864 Bl

Example 2 Transparent lacquer Epoxy resin 100 ALIGN! wt. parts Hardener A 120 II 11 Water 100 ALIGN! II 11 Sodium pentachlorophenolate - 10% solution 8 II II Pale Red R 9 II II Versal yellow G 9 II II It is prepared to an aminoamide resin (hardener) with stirring first

water containing dyes and sodium pentachlorophenolate are added, and then the epoxy resin is mixed. The resulting lacquer is stable at room temperature for 4 h, dries to Stage 1 in 5 h to Stage 5 in 24 h. It is suitable for finishing furniture parts.

Example 3

Enamel white semi-matt

Epoxy resin

Hardener B

Water

Sodium hexametaphosphate - 10% solution Laurylbenzyldimethylamine bromide 10% solution

Aqueous dispersion of copolymers of ethyl acrylate, styrene and acrylic acid, adjusted with ammonia to pH 9 to 10% titanium dioxide, rutile solution

Chalk

Kaolin

100 wt. parts

150

151

1.5

27.9

53.4

26.4

It is prepared by adding to the aminoamide resin (hardener), with stirring, all the components except the epoxy resin, which is not mixed until the last time. The enamel obtained is stable at room temperature for 4.5 hours and dries to stage 5 in 16 hours. It is suitable for painting wooden parts.

Example 4

Black matt color

Epoxy resin

Hardener A

Water

Sodium hexametaphosphate - 10% solution Laurylbenzyldimethylammonium bromide 10% solution

Sodium benzoate - 10% solution Black iron oxide Chalk

Kaolin

100 wt. parts 80

300

2.5

56.2

35.5

8.6

First, a pigment paste is prepared by homogenizing all components except the epoxy resin and dispersing the mixture on a collagen mill. The resulting pigment paste is then mixed into the epoxy resin. The paint is suitable for painting wooden parts and particle boards, but also for concrete or eternit surface treatment.

CS 273864 Bl

Example 5

Primer anticorrosive reddish brown

Epoxy resin.

Hardener C

An aqueous dispersion of copolymers of ethyl acrylate, styrene and acrylic acid, adjusted with ammonia to a pH of 9 to 10% solution. 1: 9 to 10% water solution

Zinc phosphate Micronized limestone Red iron oxide Talc

Micronized mica

In the same way as in the example, it homogenizes with an epoxy resin suitable for coating of iron constructions.

100 wt. Parts 150

3.5

3.5

350

81.3

61.3

35.2

10.0

19.2 First, a pigment paste is prepared which is obtained for 5 hours and is stable

Dries to Stage 1 in 3 h, Stage 5 to 12 h.

Claims (1)

SUBJECT OF THE INVENTION Water-based epoxy paints based on modified epoxy resins, inert organic solvents, low molecular weight polyaminoamide hardeners, water and optionally additives, consisting of: 200 wt. parts of the resin component consisting of a mixture of 1 to 99 wt. parts of epoxy resin of dian type with mol. 380 to 500 and 1 to 50 wt. parts of palm type epoxy resin of mol. 700 to 10,000 esterified 0.5 to 40 wt. fatty acids of vegetable oils, 80 to 150 wt. parts by weight of polyaminoamide hardener based on reaction products of polyamines having a carbon number of 2 to 20 and nitrogen atoms of 2 to 10 with unsaturated fatty acid adducts of vegetable oils, maleic anhydride and phenol-formaldehyde condensates in wt. ratio of polyamines and adducts of 1: 0.1 to 1.2, 1 to 50 wt. parts by weight of the organic solvent mixture containing 2 to 60 wt. % of at least one water-immiscible or sparingly miscible solvent, in particular from the group consisting of aromatic hydrocarbons and aliphatic ketones, and 40 to 98 wt. at least one water-miscible solvent of the group of aliphatic linear monovalent alcohols having carbon numbers of 4 to 8, 150 to 500 wt. parts of water and optionally up to 500 wt. parts of additives from the group comprising pigments, fillers, dyes, flow agents, biocides, defoamers, coalescents and viscosity and pH regulators.