EA036094B1 - Composition for heat-insulating coating - Google Patents

Abstract

The claimed composition relates to building materials and may be used for heat insulation of metal surfaces of industrial equipment and service surfaces of pipeline operated at moderate temperatures (up to 100C). The technical result of the invention is increased strength properties and reduced specific weight of a coating. Said result is achieved by that said coating is a composition comprising a binder, hollow microspheres, a pigment and water, wherein a butadiene-styrene rubber and acrylic polymer mix is used as a binder, the rubber content of the mix being 30-70 wt.% of the total amount of the butadiene-styrene rubber and acrylic polymer, hollow hydrocarbon microspheres are used as hollow microspheres, with the following ratio of components of the composition, wt.%: butadiene-styrene rubber and acrylic polymer mix - 25-35, hollow hydrocarbon microspheres - 20-30, pigment - 3-5, water - the balance. The optimum amount of the hollow hydrocarbon microspheres in the composition is 20-30 wt.%. Addition of less than 20 wt.% of the hollow hydrocarbon microspheres to the composition has no significant influence on the increase of strength and heat-insulation properties of the coating, increase in their content to greater than 30 wt.% in the composition results in higher composition viscosity, lower adhesion between the coating and the surface due to a lower content of the polymer binder, and leads to process scrap. The optimum amount of each component is defined according to the application of the composition.

Description

The claimed composition refers to building materials and can be used for thermal insulation of metal surfaces of industrial equipment and working surfaces of pipelines operated at low (up to 100 ° C) temperatures.

A known composition for obtaining a heat-insulating coating containing a polymer binder, a filler in the form of hollow microspheres, a technological additive and water (RF patent No. 2311397, publ. 27.11.2007).

As a polymer binder in the known composition, a latex is used, selected from the group including modified acryl acetate latex, 33-38% latex of a copolymer of butadiene, acrylonitrile and methacrylic acid, a copolymer of styrene and n-butyl acrylate in a ratio of 1: 1 by weight. Hollow ceramic microspheres with a specific gravity of 450750 kg / m ³ and a hardness on the Mohs scale of 5.0-6.0 are used as a filler. The disadvantages of the known coating include low weather resistance at normal temperatures, and at elevated operating temperatures, the use of ceramic microspheres does not provide the required level of thermal insulation and performance of the coating, which is associated with a high thermal conductivity of ceramic hollow microspheres.

Known composition for obtaining a heat-protective coating, which includes components in the following ratio, wt.%: Silicone rubber - 30-60; glass microspheres - 40-70 and components of a fire-retardant composition, wt%: silicone rubber - 20.0-79.5; glass microspheres - 20.0-60.0; boron nitride - 0.5-20.0 (RF patent No. 2039070, publ. 09.07.1995).

The composition is used to obtain a coating that has heat and fire retardant properties. The adhesive strength of the coating is up to 5 kg / cm ² . The disadvantage of this composition is the rather high thermal conductivity of the coating - up to 0.23 W / m ° C.

Known heat-insulating coating based on hollow microspheres, made of a water-suspension composition with a viscosity of 1 to 100 Pa-s, including a mixture of a polymer binder 5-95 vol.% With hollow microspheres 5-95 vol.% And a stabilizer, as a polymer binder composition contains water-based polymer latex composition containing 10-90 vol.% (co) polymer selected from the group consisting of acrylate homopolymer, styrene-acrylate copolymer, styrene-butadiene copolymer, polystyrene, butadiene polymer, polyvinyl chloride polymer, polyurethane polymer, vinyl polymer or polymer or their mixtures and 10-90 vol.% of a mixture of water, surfactant, as hollow microspheres, the composition contains a mixture of microspheres with different sizes of 10-500 microns and different bulk density of 50-650 kg / m ³ (RF patent No. 2374281, published on November 27, 2009). A mixture of a polyhydric alcohol with a polyhydric carboxylic or amino acid is used as a stabilizer in the composition for the known coating. The disadvantages of this thermal insulation coating are low heat and weather resistance, as well as a sufficiently high specific gravity of the coating, which in turn increases the load on the structures to which the coating is applied.

The closest in technical essence and the achieved result is a heat-insulating coating that has the ability to form a film, which is a composition including uniformly distributed in it and constituting at least 51 wt.% Of the total amount of a mixture of air-filled ceramic and silicon microbeads in a ratio of 1: 1 and carbon microfibers with fibrils, a mixture of styrene-butadiene rubber and an acrylic polymer and at least one pigment. The mixture of microbeads is 70-75 wt.%, Microfibers 5-7 wt.% And rubber 30-70 wt.% Of the total amount of the mixture of styrene-butadiene rubber and acrylic polymer. The ratio of the components that make up the composition is equal, wt%: a mixture of styrene-butadiene rubber and acrylic polymer - 26-30, a mixture of microbeads and microfibers with fibrils - 19.5-24.6, pigment or pigments - 3.75-5, 5, water - the rest (RF patent No. 2206550, publ. 20.06.2003). The disadvantage of this thermal insulation coating is its low thermal protection and strength.

The technical result of the claimed invention is to increase the thermal insulation and strength properties of the coating, to reduce its specific weight.

This result is achieved by the fact that the thermal insulation coating is a composition comprising a binder, hollow microspheres, a pigment and water, where a mixture of styrene-butadiene rubber and an acrylic polymer is used as a binder, and the rubber in the mixture is 30-70 wt% of the total amount of butadiene -styrene rubber and acrylic polymer, hollow carbon microspheres are used as hollow microspheres, with the following composition ratio, wt%: a mixture of styrene-butadiene rubber and acrylic polymer - 25-35, hollow carbon microspheres - 20 - 30, pigment - 3 -5, water - the rest.

SKS-10 rubber is used as styrene-butadiene rubber, and polymethyl acrylate is used as an acrylic polymer.

Hollow carbon microspheres obtained by pyrolysis of phenol-formaldehyde hollow microspheres in argon at 1200 ° C for 4 hours are used as hollow microspheres. The resulting microspheres have a size of 20 to 100 μm. Any kind of pigment is used

- 1 036094 neral pigment, for example titanium dioxide grade P-02.

The use of hollow carbon microspheres in the composition in an amount of 20-30 wt% provides an increase in the strength properties of the coating due to the fact that the carbon microspheres obtained by pyrolysis have a rougher surface than hollow ceramic microspheres, which significantly increases the physical adhesion forces between the surface of the microspheres and the binder mixture styrene butadiene rubber and acrylic polymer. In addition, various functional groups can be located on the surface of micropores of carbon microspheres, which act as activation centers for intermolecular chemical interaction with a polymer binder, which significantly strengthens the structure of the polymer matrix of the coating.

Thus, the use of hollow carbon microspheres in the composition can significantly increase the strength characteristics of the coating. Hollow carbon microspheres have a significantly lower thermal conductivity coefficient than ceramic hollow microspheres; therefore, their use in a composition makes it possible to obtain a coating with higher thermal insulation properties. In addition, hollow microspheres are much lighter than ceramic microspheres, which makes it possible to reduce the specific weight of the coating and, as a consequence, reduce the weight load on the structural elements of the treated surfaces.

Adding less than 20 wt% hollow carbon microspheres to the composition does not give a significant effect of increasing the strength and thermal insulation properties of the coating, an increase in their content over 30 wt% in the composition leads to an increase in the viscosity of the composition, deterioration of the adhesion of the coating to the treated surface, due to a decrease in the content of the polymer binder , leads to a technological defect.

The introduction of more than 5 wt% of mineral pigment into the composition does not lead to a saturated color of the coating, while the cost of the composition increases due to the high cost of pigments. The introduction into the composition of less than 3 wt.% Of mineral pigment does not lead to the effect of coloring the polymer film of the coating. However, the amount of pigment introduced is a special case, since it depends only on the desire of the consumer.

The claimed invention is illustrated by the following examples.

Example 1.

A composition containing, wt%: a mixture of styrene-butadiene rubber and polymethyl acrylate with a rubber content - 30-25, hollow carbon microspheres - 20, pigment - 5, water - the rest, is applied to a previously prepared (cleaned from rust, degreased) metal surface ... The composition is applied with a brush, roller, spray gun at a temperature of 10 to 30 ° C at a relative humidity of not more than 70% indoors or in dry weather.

Example 2.

Used a composition containing the same components as in example 1, but in the following ratios, wt.%: A mixture of styrene-butadiene rubber and polymethyl acrylate - 35, hollow carbon microspheres - 25, pigment - 4, the rest is water. The technology for applying the composition according to example 1.

Example 3.

Used a composition containing the same components as in example 1, but in the following ratios, wt.%: A mixture of styrene-butadiene rubber and polymethyl acrylate - 30, hollow carbon microspheres - 30, pigment - 3, the rest is water. The technology for applying the composition according to example 1.

Properties of coatings obtained using known and proposed compositions are shown in the table.

Property Composition Prototype Proposed by example 1 2 3 1. Thermal conductivity, W / mK 0.25 0.14 0.18 0.15 2. Tensile strength, kgf / mm ² 3.0 3.6 3.2 3.8

Experimental work carried out when testing the compositions of the heat-insulating coating, the ratios of the components in which went beyond the ratios limited by the present invention, both in the direction of decreasing and in the direction of increasing, showed that their performance in terms of heat-insulating properties and strength is much lower.

The coating according to the invention has a low specific weight, provides good adhesion to the surface, is technologically easy to apply, the coating film on the surface is durable and has increased strength and thermal insulation properties.

Claims (2)

CLAIM Composition for heat-insulating coating comprising a binder, hollow microspheres, inorganic pigment and water, which contains a mixture of styrene-butadiene rubber and polymethyl acrylate as a binder, and the amount of rubber in the mixture is 30-70 wt% of the total - 2 036094 amounts of styrene-butadiene rubber and polymethyl acrylate, and as an inorganic pigment contains a mineral pigment titanium dioxide, characterized in that as hollow microspheres it contains hollow carbon microspheres with a size of 20 to 100 microns, obtained by pyrolysis of phenol-formaldehyde hollow microspheres in argon at a temperature of 1200 ° C for 4 hours, with the following ratio of the components of the composition, wt%: Mixture of styrene-butadiene rubber and polymethyl acrylate - 25-35 Hollow carbon microspheres - 20-30 Mineral pigment titanium dioxide - 3-5 Water is the rest.