RU2424905C1 - Method of producing heat isolation gradient coat - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to chemical processes, particularly, to production of heat isolation gradient coat. Epoxy resin is first mixed with hollow glass microspheres. Then hardener and phosphorus acid glycidyl ethyl ether are added in the following ratio (wt %): epoxy resin - 100; phosphorus acid glycidyl ethyl ether - 15-25; hollow glass microspheres - 25-45; stoichiometric amount of hardener.

EFFECT: higher heat isolation properties.

2 tbl

Description

The invention relates to a method for producing a thermal insulation coating used in industry, public utilities and other areas where surface protection against corrosion and thermal protection is required, in particular for protecting pipelines operating in permafrost regions, under water and at large temperature extremes.

A self-extinguishing polymer composition is known including an epoxy resin, an oligoamidoamine hardener, ammonium phosphate, a cured phenol formaldehyde resin powder and hollow glass microspheres (RF patent 2220990, IPC C08L 63/00, C08K 13/02, C08L 61:10, C08L 77:06 5:32, C08K 7:20, publ. 01/10/2004). However, this composition does not provide the necessary thermal insulation properties and is not intended to obtain coverage, but is used to fill sections of cellular structures in aircraft.

Known anti-corrosion and heat-insulating coating for thermal insulation of pipelines of heat and water supply, made of a composition comprising a polymer binder and hollow microspheres, and containing as a polymer binder a water-emulsion polymer latex composition selected from the group comprising an acrylate homopolymer, styrene-acrylate butadiene copolymer, butadiene styrene copolymer, polystyrene, butadiene polymer, polyvinyl chloride polymer, polyurethane polymer, vinyl acetate polymer or copolymer or x and the mixture of water and a surfactant (Patent RF 2251563, MPK7 C09D 5/02, 5/08, publ. 10.05.2005). The prepared mixture is applied to the surface of the pipe using a roller. After a day after applying the first layer, the next coating layer is applied to the pipe. Thus, a five-layer coating is applied with a total thickness of the finished layer of about 2 mm. The coating has good adhesion and physico-mechanical properties. However, the technology for its production is complex and multi-stage and requires a long investment of time.

A known composition for producing an anticorrosive, fire-resistant and heat-insulating coating, comprising an epoxy resin, a hardener, hollow microspheres and auxiliary additives as a binder, and containing as a hollow microspheres a mixture of hollow microspheres with different sizes ranging from 10 to 500 microns and bulk density in the range from 650 to 50 kg / m ³ selected from the group comprising hollow glass microspheres, hollow ceramic microspheres, hollow polymer microspheres, hollow man-made (ash) microspheres and whether their mixtures (RF patent 2301241, IPC C09D 163/00, 5/08, 5/18, C08K 7/22, publ. 06/20/2007). The known coating is multifunctional, simultaneously performing the functions of a heat-insulating, fire-resistant coating with increased corrosion resistance in various aggressive environments. The known method requires increased time to select microspheres of various compositions with different diameters and different densities.

The closest in technical essence and the achieved technical result is a method of producing a heat-insulating material based on syntactic foam, in which the initial components are dosed, two reactive components of the binder are mixed, the resulting composition is filled with microspheres, the obtained component is poured to obtain a heat-insulating material and cured, characterized the fact that the filling of each of the reactive components of the binder with microspheres is carried out separately, after which mixed filled reactive components of the binder (RF patent 2187433, IPC7 В29С 67/20, C08J 9/32, F16L 59/02, B29K 105: 04, B29L 9:00, B29L 23:00, publ. 08/20/2002). The method is characterized in that hollow glass microspheres and / or polymer microspheres having a hydrostatic strength of at least 2 MPa are used as microspheres, and amine and / or amide type epoxy resins and hardeners are used as reactive components of the binder. However, the coating obtained on the basis of this composition does not have sufficient thermal insulation properties, because its thermal conductivity is not low enough.

The technical result, which the invention is directed to, is to increase the thermal insulation properties of the coating.

The technical result is achieved by the fact that in the method for producing a heat-insulating gradient coating, in which epoxy resin, hardener and hollow glass microspheres are mixed and cured, it is new that the epoxy resin and hollow glass microspheres are pre-mixed, then a hardener and glycidyl ether of phosphorus acids are introduced at the following ratio of components, parts by weight:

epoxy resin one hundred phosphoric acid glycidyl ether 15-25 hollow glass microspheres 25-45 hardener stoichiometric amount.

Table 1 shows examples of the compositions of the proposed compositions. Table 2 shows the properties of the proposed coatings.

Resins of grades: ED-20, ED-16, ED-8 (GOST 10587-84), E-40 (OST 10-416-76) were used as epoxy resins. As glycidyl ethers of phosphorus acids, we used: triglycidyl phosphate (THPT), diglycidyl methylphosphate (DHFT), diglycidyl methylphosphonate (DHMP). All glycidyl ethers of phosphorus acids used are transparent, colorless, non-volatile, slow-burning liquids with a low viscosity (0.001-0.002 Pa · s at 25 ° C) and an epoxy content of 38-48% (Stepashkina L.V., Rizpolezhensky N.I. Synthesis and properties glycidyl ethers of phosphorus acids. // Izv. AN SSSR. Ser.chem. - 1967. No. 3. - S.607-610).

As hardener used: monocyanethyl diethylenetriamine (UP-0633M, TU 6-05-1863-78), eutectic of 4,4'-diaminodiphenylmethane and metaphenylenediamine (UP-0638, TU 6-09-15-295-77), N-cresilethylenediamine (AF-2, TU 2494-511-0020333521-94), polyethylene polyamine (PEPA, TU 6-02-594-80), isomethyl tetrahydrophthalic anhydride (iso-MTHFA, TU 6-09-3321-73).

As microspheres, hollow glass microspheres of the MSO A9 brand (TU 6-48-91-92) were used.

The composition was prepared by thoroughly pre-mixing the epoxy resin with microspheres and then introducing glycidyl ether and hardener.

The ratio of epoxy resin to glycidyl ether of phosphorus acids corresponds to their incompatibility. During the curing process, the composition delaminates, resulting in a coating with a gradient in composition and, accordingly, cross-sectional properties. In the upper part of the coating, an increased concentration of epoxy resin and microspheres is formed. The coating surface, consisting mainly of an epoxydian oligomer and microspheres, provides high moisture and chemical resistance of the coating and low thermal conductivity. On the metal surface in the lower part of the coating, a composition is formed, consisting mainly of glycidyl ether of phosphorus acids having a lower viscosity value, which ensures good wettability of the metal surface of the proposed composition, high strength and adhesion of the coating. In addition, a change in composition over the thickness of the coating reduces the difference between the thermal expansion coefficients of the lower coating layer and the metal substrate, which increases the adhesion strength during thermal cycling.

The curing of the composition is carried out depending on the activity of the hardener at a temperature of 18-150 ° C for 0.5-24 hours. A gradient coating is obtained by applying with a brush or spatula.

Thus, the resulting coatings have good thermal insulation properties, which allows them to be successfully used to protect pipelines.

Table 1 Structure The content of components, parts by weight, according to examples one 2 3 four 5 6 7 8 9 Epoxy resin one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred one hundred Phosphorus Acid Glycidyl Ether 10 10 10 fifteen fifteen fifteen twenty twenty twenty Microspheres 25 35 45 25 35 45 25 35 45 Amine hardener Stoichiometric amount

table 2 Properties Example rate one 2 3 four 5 6 7 8 9 The density of the composition, kg / m ³ 320 310 300 330 310 300 340 320 310 The coefficient of thermal conductivity, W / m · K 0.03 0.025 0.02 0.03 0.025 0.02 0.03 0.025 0.02

Claims (1)

A method of obtaining a heat-insulating gradient coating, in which epoxy resin, hardener and hollow glass microspheres are mixed and cured, characterized in that the epoxy resin and hollow glass microspheres are pre-mixed, then a hardener and glycidyl ether of phosphorus acids are introduced in the following ratio of components, parts by weight :
epoxy resin one hundred phosphoric acid glycidyl ether 15-25 hollow glass microspheres 25-45 hardener stoichiometric amount