CS246778B1 - Dispersion binder for anticorrosive materials - Google Patents

Abstract

Dispersion binder for anticorrosive materials is based on aqueous dispersions of ethanolammonium salts of copolymers of acrylic acid esters with acrylic acid and/or methacrylic acid and other vinyl monomers and a hydrosol of silicon dioxide with modifying additives facilitating processing. This composition creates a stable dispersion system with anticorrosive properties, which is suitable for formulating anticorrosive coatings. The binder contains metaphosphoric acid salts for better processability.

Description

The present invention relates to a dispersion binder which is used for the formulation of anticorrosive materials, in particular a binder ^. anticorrosive protective agents intended for application to ferrous and non-ferrous metals, silicate materials and porous plastics.

Binders for these coatings of the same purpose have changed substantially in recent times. Initially, there was a tendency to achieve maximum complex properties, including high inhibitory potency, good theological properties, and resistance to environmental conditions. Binding oil or synthetic resin based binders meet these requirements. The anticorrosive pigments are predominantly lead, zinc yellow and chrome pigments. All these pigments are toxic and necessarily require said binders. (Masomoto Tachiibona, Shikizai, 52,268 (1979).)

Current needs of the technology are mainly motivated by substitution of deficit raw materials, energy saving and ecological requirements. Water-based binders comply with environmental requirements, oil product savings and fire safety.

However, binders of this kind used so far require various additives and modifiers so that the aqueous phase of the binder does not reduce the anticorrosive properties and ensure sufficient compatibility with fillers and pigments. These include, for example, nitrites, chromates, phosphates and borates [Ivanov E. S. / Metallo corrosion inhibitors, ed. Znanie, Moscow 1980]. Examples are fatty acid-containing imidazoles (U.S. Pat. No. 3,758,493), phenol-formaldehyde resins with secondary amines (U.S. Pat. No. 3,868,324), benztriazole with zinc salts (U.S. Pat. No. 3,794,604), and the like. .

Advantages of the dispersion binder according to the invention are good compatibility with all kinds of anticorrosive pigments and fillers, good anticorrosive properties, removal of volatile organic compounds and ecological safety.

The dispersion binder-based anticorrosive compositions of the present invention have the same anticorrosive properties as analogous conventional compositions. They can be applied by spraying or spraying onto cleaned substrates, which may not be dry. Based on the dispersion binder, anticorrosive materials can be formulated in a wide range of properties, both physical and mechanical and chemical.

It is an object of the present invention to exploit the synergistic properties of aqueous dispersions of ethanolammonium salts of copolymers of esters of acrylic acid with acrylic acid or methacrylic acid and other vinyl monomers with silica hydrosol. Copolymers containing carboxyl groups or salts thereof have increased adhesion to substrates, especially metal substrates. Ethanolamines react with carboxylated copolymers to neutralize them.

It has been shown that an equilibrium mixture of esters and amides is formed which exhibits anticorrosive properties. Hydrosol of silica with particle size below 30 nm in the resulting complex compounds increases the adherence of the mixture to substrates, increases resistance to mechanical stress, heat resistance and aggressive environment. Metaphosphoric acid salts modify the rheological properties of the mixture, and at the same time act passivatively on metal surfaces.

The dispersion binder according to the invention has good mechanical stability, anticorrosive properties, is environmentally and hygienically harmless, non-flammable and shows good compatibility with anticorrosive pigments and fillers. Examples

He did

A dispersion binder for anticorrosive materials is prepared by homogenizing 62% by weight. aqueous dispersions of styrene-2-ethylahexyl acrylate-acrylic acid with a dry weight of 50 wt. the ratio of individual comonomers 45: 52: 3, which is neutralized by 3 wt. % of triethanolamine and 33% by weight of the neutralized mixture are added with stirring. % hydrosol of silica having a dry weight of 25% by weight, a particle size of 15 to 20 nm, a specific surface area of 230 m ² g ^-1 and an alkaline salt content of 0.3% by weight. and 2 wt. Sodium hexametaphosphate with a dry weight of 10% wt. Upon homogenization, a dispersion binder can be processed at a temperature range of -10 ° C to +180 ° C, resistant to pH changes in the range of 2 to 14 and with high mechanical stability.

Example 2

From 33.9 parts of the dispersion binder of Example 1, an anticorrosive coating composition was prepared by homogenization with 1.0 part of calcium stearates, 64.5 parts of quartz sands with a grain size of up to 0.2 mm and 0.6 parts of titanium dioxide, all in weight. parts. The corrosion rate of structural steel in a strongly aggressive environment at a coating thickness of 0.120 mm was k = 1.28 nmr ^-1 and at the same thickness of synthetic anticorrosive paint was 6.35 nmr ^-1 . The corrosion loss for 1 year was 0.27 gm ^-2 for the dispersion mass and 6.38 gm ^{-2 for the} synthetic paint. Example 3

A dispersion binder for anticorrosive paints is prepared by homogenizing 50 wt. % aqueous dispersion of vinyl chloride-ethyl acrylate-methacrylic acid with a dry weight of 40 wt. and mass. ratio of individual comonomers 15: 77:

%, Which is neutralized with 10 wt. mw 246778 with noetanolamine, 35 wt. 30% w / w silica, a particle size of 10-15 nm, a specific surface area of 350 m ² g ^-1 , an alkali salt content of 0.4 wt. and 5 wt. potassium trimetaphosphate, on a dry weight basis of 15% This results in a stable dispersion binder suitable for the preparation of anticorrosive materials.

Example 4

The spraying and dipping anticorrosive composition is prepared from 65 parts of the dispersion binder of Example 3, 20 parts of ground limestone with a particle size of up to 0.1 mm, 10 parts of a core pigment, the core being iron oxides coated with zinc phosphate and 5 parts of quartz sand up to 0,2 mm, all in weight parts. Stirring of the components gives a stable mass with a viscosity of 150 mPas, which dries to Stage 2 in 1 h and Stage 5 in 6 h. The corrosion rate at aggressiveness level 5 was 0.12nmr ^-1 at 0.1 mm thickness and oil corrosion resistant. of the same thickness was 5.32 nmr ^-1 . Corrosion loss after 1 year was not measurable for dispersion mass and for oil paint 6.16 gnr ² .

Claims (4)

A dispersion binder for anticorrosive materials based on aqueous dispersions of synthetic polymers, characterized in that it consists of 50 to 70% by weight. aqueous dispersions of ethanolammonium salts of a copolymer of acrylic acid esters with acrylic acid and / or methacrylic acid and other vinyl monomers having a dry weight of 30 to 60 wt.%, from 20 to 50 wt. % hydrosol of silica with a dry matter content of 15 to 30 wt. and from 2 to 5 wt. % salts of metaphosphoric acid having a dry weight of 5 to 20 wt. Dispersion binder according to claim 1, characterized in that the aqueous dispersions of the ethanolammonium salts of the copolymers consist of copolymers of styrene-acrylic acid-acrylic acid and / or methacrylic acidNALEZ, or copolymers of vinyl chloride-acrylic acid-acrylic acid and / or acid. methacrylic, wherein the individual comonomers are in a weight ratio of 15: 77:: 8 to 50: 47: 3. 3. The dispersion binder of claim 1, wherein the silica hydrosol has a particle size of less than 30 nm, a specific surface area of greater than 100 m < ² > g < ^-1 and an alkali salt content of less than 0.6% by weight. hydrosol dry matter. 4. A dispersion binder according to claim 1, wherein the metaphosphoric acid salts are the alkali salts of trimetaphosphoric acid or hexametaphosphoric acid.