RU2654753C1 - Enamel for weatherproof corrosion-resistant coatings - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to enamels for weather-resistant corrosion-resistant coatings used for external and internal works in the protection of metals, wood, concrete and other surfaces, which are operated under particularly aggressive environments. Enamel includes a semi-finished enamel, to which an organobentonite «CLAYTON» rheological additive is introduced, pigments, filler, amine type curing agent. Semi-finished enamel contains the following ratio of ingredients in wt%: 21.7–25.30 of pigments, 9.40–13.5 of filler, 1.50 of an organobentonite «CLAYTON» rheological additive, 6.13–6.40 of organic solvent, 56.90–57.46 by a dry residue is an epoxydian resin solution. Organic solvent has a composition, wt%: 42.20–48.90 of ethyl cellosolve, 57.80–51.10 of toluene. Amine type curing agent is contained in an amount of 2.20–28.60 parts by weight per 100 parts by weight of the semi-finished product.

EFFECT: proposed is an enamel for weatherproof corrosion-resistant coatings.

1 cl, 4 tbl

Description

The present invention relates to paints and varnishes and can be used for external and internal work in the protection of metals, wood, concrete and other surfaces operated in especially aggressive environments.

Known widely used enamel EP-525 (GOST 22438-85, Publishing house of standards, 1985), which is a suspension of pigments and fillers in a solution of epoxy resin E-41 in a mixture of organic solvents with the addition of hardener No. 1. However, it has limited atmospheric resistance.

The closest technical solution to the proposed one is that set forth in the RF patent for invention No. 2307143 (Bull. No. 27 dated 09/27/2007), the solution according to which the enamel for coating is a kit comprising prefabricated enamel from a solution of epoxydianine resin - an amine product of hydroxyphenylene epoxidation, amine hardener and, in addition, pigments, filler - a mixture of microtalc, kaolin, micromica, aerosil, an organic solvent.

Depending on the enamel color, the pigments used are red iron oxide pigment, titanium dioxide, lead molybdate, lead lemon citron, lead yellow crown, carbon, phthalocyanine blue, pigment chromium oxide.

A mixture of acetone and toluene is used as the organic solvent of the epoxy resin, while the prefabricated enamel contains xylene and ethyl cellosolve to ensure the required viscosity.

As hardeners of amine type are used:

1) 50% solution of hexamethylenediamine in methylcarbinol;

2) polyamide with an amine number of 140 ÷ 300;

3) polyethylene polyamine or diethylene triamine.

The semi-finished product contains 50-60 wt. % epoxidian resin - the basis and has the following ratio of ingredients, wt. %:

pigments 17-30 filler 7-15 organic solvent 5.22-6.93 epoxy resin solution rest

The ratio of ingredients in the enamel is in wt. hours:

prefabricated enamel one hundred amine type hardener 2.10-28.60

The disadvantages of this technical solution include the low conditional viscosity of the composition (15-35 s at a temperature of (20 ± 0.5) ° C on a B3-246 viscometer with a nozzle diameter of 4 mm), which does not ensure its thixotropy when applied to a protected surface and requires application of 3-5 layers of enamel to provide a coating thickness of 170-300 microns. In addition, in the process of preparation of enamel, 4 types of solvents are used, which complicates the process.

An object of the invention is the creation of a thixotropic composition that provides the application of enamel in 1 pass, ensuring the thickness of the applied layer at least 160 microns in terms of dry residue, reducing the types of solvents used in the manufacture of enamel while maintaining its inherent protection properties of the surface to be coated.

The technical result is achieved by the fact that the enamel for coating, which is a semi-finished product of enamel from a solution of epoxy resin, an epoxidation product of hydroxyphenylene with a mass fraction of non-volatile substances of 56.9-57.46%, an amine hardener, pigments and a filler, additionally contains the rheological additive organobentonite " CLAYTON HY. " Xylene is removed from the composition of the organic solvent of the semi-finished enamel, and the enamel ingredients are distributed in the following ratio, wt. %:

pigments 21.70-25.30 filler 13.50-9.40 organobentonite rheological additive "CLAYTON" 1,50 organic solvent prefabricated enamel 6.40-6.13 epoxy resin solution (based on solids) 56.90-57.46

The organic solvent of the semi-finished enamel, in turn, has a composition, wt. %:

ethyl cellosolve 42.20-48.90 toluene 57.80-51.10

The ratio of ingredients in the enamel is in wt. hours:

semifinished one hundred amine type hardener 2.20-28.60

Table 1 shows the various formulations of semi-finished enamel

Preparation of prefabricated enamel

In a closed dissolver load the calculated amount of a solution of epoxy resin with a concentration of 56.90-57.46 wt. % solids, then pigments, a mixture of fillers and a rheological additive are added. The dissolver is equipped with a dispersing mill with a rotation speed of up to 1500 rpm. Pre-dispersion is carried out within 1-2 hours. The resulting batch is passed through a horizontal bead mill with a capacity of up to 1500 kg / h with admission to the mixer. When obtaining a grinding degree of not more than 40 μm, the calculated amount of ethyl cellosolve, toluene is introduced into the enamel prefabricated, the semi-finished product is mixed for 1-2 hours and after determining the viscosity and mass fraction of non-volatile substances, it is poured into the container.

Enamel preparation and coating

Before coating, a hardener is introduced into the enamel prefabricated at room temperature, the mixture is thoroughly mixed to be applied to the coating surface by airless spraying or other methods.

Table 2 shows the download hardeners in wt. parts per 100 wt. h semi-finished enamel.

Tables 3, 4 show the characteristics of the proposed enamel.

The tables show that, having physico-mechanical, resistance characteristics close to the prototype enamel, the claimed enamel, due to the sufficient viscosity and thixotropy provided by the high mass fraction of solids in the semi-finished product in combination with the introduction of CLAYTON HY organobentonite into the semi-finished product of the rheological additive , can be applied to the protected surface with the formation in one pass of a non-flowing wet layer at a temperature of (20 ± 2) ° С with a thickness of 180-260 microns and a dry film with a thickness of 160-180 microns (40-60 microns prototype), which is very important for protection You are metal products in the oil and gas industry and shipbuilding.

The exclusion of xylene solvent from the enamel composition increases the manufacturability of its manufacture.

Claims (4)

Enamel for weather-resistant corrosion-resistant coatings, including semi-finished enamel based on a solution of epoxy resin, pigments, filler, hardener of amine type, organic solvent of a semi-finished product, characterized in that a rheological additive - organobentonite "CLAYTON" is introduced in the following ratio of components, wt.%: pigments 21.70-25.30 filler 13.50-9.40 rheological additive 1,50 organic solvent prefabricated 6.13-6.40 epoxy resin solution (by dry residue) 56.90-57.46, while the hardener of the amine type is contained in an amount of 2.20-28.60 wt.h. per 100 parts by weight semi-finished product, and the organic solvent of the semi-finished enamel has a composition, wt.%: ethyl cellosolve 42.20-48.90 toluene 57.80-51.10