RU2507231C1 - Method of making fireproof coating for fibre-glass - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method can be used in different fields of industry for fireproofing fibre-glass. The method of producing a fireproof coating for fibre-glass by applying a coating based on chlorinated polyvinyl chloride resin, an organic solvent coupled with foaming filler, and subsequently drying the coating at room temperature. The organic solvent used is a mixture of butyl acetate and acetone in ratio of 1:1; the foaming filler used is a phosphorus-boron-nitrogen-containing oligomer which is obtained in advance by reacting methyl phosphite borate, epoxy resin ED-20 and aniline in weight ratio of 2.5:1:2.5, in amount of 2.5-7.5 pts.wt per 100 pts.wt coating. The coating is deposited in a layer with thickness of 1 mm and dried for 2 days.

EFFECT: invention enables to obtain a coating with a smaller thickness, cuts the drying time of the coating and provides high fire-protection for fibre-glass.

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Description

The invention relates to methods for fire protection of materials by applying a fire retardant coating. It can be used in various industries for fire protection fiberglass.

A known method of obtaining a heat-insulating and fire-resistant multilayer combined polymer coating, comprising sequentially applying to the possibly pre-heated surface of the coating layers, first a liquid-ceramic coating from a polymer composition containing a binder, a mixture of hollow microspheres, and auxiliary target additives, then, if necessary, apply one or several layers of fiberglass and then apply one or more layers of polymer intumescent flame retardant compositions with additives that provide an intumescent coating, and then carry out the final drying of the coating, while the liquid-ceramic coating is made of a composition containing, as one of the auxiliary additives, flame retardant ammonium polyphosphate (US Pat. RF 2352601, C09D 5/02, C09D 5/18, B32B 27/20; publ. 04/20/2009).

The known method is technologically complex and involves several stages.

A known method of obtaining a fire-resistant coating, comprising applying to the surface of several layers of a composition containing a binder and filler, with an intermediate drying of each layer and final heat treatment of the coating, characterized in that heat-insulating layers are applied to the surface first, and then fire-resistant layers, while drying each intermediate the layer is carried out at 20-80 ° C, and the final heat treatment of the coating at 80-150 ° C, and the total thickness of the fire-resistant layers does not exceed 3 mm (US Pat. RF 2039070, C09D 183/04, C09D 5/18, B05D 1/38; about UBL. 05.09.1995).

However, the composition of the composition according to this method is multicomponent, the technology includes several stages, the coating has a large thickness.

A known method of applying heat-protective coatings, which include chlorosulfonated polyethylene, toluene, thermally expanding graphite, zinc oxide, magnesium oxide, stearic acid, diphenylguanidine. The coating is applied with a spray gun or brush on a previously painted structure up to 3 mm thick, including complex shapes (I-beam, channel, various instruments and assemblies), in the field, that is, the drying temperature should be 18-25 ° C (Pat. RF 2186813 , C09D 123/34; publ. 08/10/2002) ..

However, this method is applicable for steel structures, requires a large coating thickness. The composition has a complex formulation.

The closest is the method of fire protection of metal structures by applying a fire-retardant coating based on perchlorovinyl resin, an organic solvent in combination with a foaming filler - the condensation product of formaldehyde, dicyandiamide, sorbitol, oxalic acid. The resulting composition is applied to metal samples with a brush, roller or by spraying with a layer thickness of 1.1-1.2 mm. Samples coated on them are dried in air for 6-7 days under normal conditions (US Pat. RF 2185408, C09D 127/24, C09D 5/18; publ. 20.07.2002).

However, this method requires a long exposure, a larger coating thickness and is used for application to metal structures. Obtaining a coating composition is technologically time-consuming due to the complexity of the synthesis of the expanding filler.

Objective: the development of a fire-retardant coating based on perchlorovinyl resin for fiberglass.

The technical result is to reduce the thickness of the coating, reducing the drying time of the coating and providing high fire protection for fiberglass.

The technical result achieved is achieved by the fact that according to the method for producing a flame retardant coating for fiberglass, by coating on the basis of perchlorovinyl resin, an organic solvent in combination with a foaming filler and subsequent drying of the coating at room temperature, a mixture of butyl acetate and acetone in the ratio of 1 is used as an organic solvent : 1, as a foaming filler, a phosphorus-borazo-containing oligomer previously obtained as a result of interaction borate methylphosphite, epoxy resin ED-20 and aniline in a mass ratio of 2.5: 1: 2.5, in an amount of 2.5-7.5 wt.h. per 100 parts by weight coating, and the coating is applied in a layer 1 mm thick, and drying is carried out for 2 days.

CPVC brand perchlorvinyl resin (OST 6-01-37-88, amend. 1.2) is used in the production of adhesives, coatings as a polymer binder.

Organic solvent: a mixture of butyl acetate (GOST 8981-78) and acetone (GOST 2603-79).

As a foaming filler, a phosphorus-borazo-containing oligomer (FEDA) is used, which was previously obtained by reacting methylphosphite borate, ED-20 epoxy and aniline in a mass ratio of 2.5: 1: 2.5. Methyl phosphite borate was previously used for flame retardant modification of cellulosic materials (US Pat. RF 2254341 C1, C08B 15/05, publ. 06/20/05). To prepare the FEDA, the required amount of ED-20 epoxy and aniline are loaded into the mixer, mixed until a homogeneous mass is obtained. Then, the calculated amount of methylphosphite borate is slowly added dropwise, preventing the reaction mass from heating above 25 ° C. The synthesis is carried out with constant stirring. FEDA preparation time is 2.5-3 hours. Some physical properties of the oligomer are presented in table 1.

Table 1 Physical properties Value Relative density, g / cm ³ 1.4914-1.5478 Refractive index 1,461-1,496

The presence of phosphorus, boron and nitrogen atoms in the phosphorus-boron-containing oligomer, which are inhibitors of the combustion and oxidation processes, makes the composition based on perchlorovinyl resin fire resistant. In addition, a significant content of phosphorus and boron in the structure of the substance contributes to the achievement of the maximum result without resorting to the use of large concentrations.

The stated limits of FEDA are due to the fact that a decrease in the content of FEDA leads to a decrease in fire resistance, and an increase in its content contributes to an increase in the curing time of the composition. The claimed coating thickness is explained by the fact that with a decrease in the coating thickness the necessary fire retardant properties are not achieved, and an increase in the coating thickness leads to an increase in the curing time of the composition.

This composition allows to obtain coatings based on perchlorovinyl resin with increased fire protection.

The method of applying a flame retardant coating to fiberglass is as follows.

Before coating based on perchlorovinyl resin, a phosphorus-boron-containing oligomer is introduced into the composition. This method is used for fire protection fiberglass. The resulting composition is applied repeatedly to fiberglass samples using a brush with a thickness of 1 mm. Samples coated on them are dried in air for 2 days under normal conditions.

In order to determine the effectiveness of the developed flame retardants, coatings were tested by exposing the treated specimen to fiberglass to an open flame source. The test setup is assembled on the basis of a laboratory chemical tripod and installed in a well-ventilated room. Samples for measurements have the following dimensions: length - 50 mm, width - 50 mm, thickness - 1.8-2 mm. Fire retardant coating thickness 1 mm. Before measurements, the coated samples are dried at room temperature for at least two days. The sample prepared for testing is fixed vertically in a tripod. Use a universal gas burner Bunsen equipped with a nozzle with a hole diameter of 7 mm. A gas burner (using household gas), which is in a horizontal position at a distance of at least 200 mm from the sample, is ignited and adjusted so that the flame height is 150-180 mm. The flame is directed exactly to the center of the fixed fiberglass specimen. The air supply is regulated until the yellow tip of the flame disappears.

Temperature measurements are carried out by the device - S-300.3 pyrometer (GOST 28243-96 "Pyrometers. General technical requirements"). The principle of operation of the pyrometer is based on measuring the thermal radiation power of the measurement object mainly in the ranges of infrared radiation and visible light.

Using a pyrometer, a temperature change is recorded on the unheated surface of the prototype over time until the limit state of the fiberglass prototype is reached. For the limiting state of the material, the appearance of a black spot on the unheated side of the prototype was taken — loss of integrity of the sample. Next, measure the height of the coke formed, by the change in the thickness of the sample before and after the test, the coefficient of expansion is calculated.

As a result of the tests, it was found that the achieved expansion coefficient of the order of 5.55-6.47 significantly reduced the weight loss of the sample from 24.7% to 6.2-8.6%, and the time to reach the limit state of the experimental samples increases by 1.7 -2.0 times (Table 2).

table 2 Test The content of the foaming filler, wt.h. No foaming agent 2,5 5,0 7.5 Expansion coefficient 1.55 6.0 5.55 6.47 Mass loss% 24.7 8.6 6.4 6.2 Time to reach limit state, s 29th 52 57 63 The temperature of the unheated side of the substrate at the beginning of the expansion of the coating 98.1 68,4 62.8 60,4 The temperature of the unheated side of the substrate after 25 s, ° C 126.2 81.3 79.5 78.6

The technical and economic effect obtained from the application of this method of fiberglass fire protection consists in the fact that its application allows applying a layer of smaller thickness, shortening the drying time of the coating and providing high fire protection for fiberglass.

Claims (1)

A method of obtaining a fire retardant coating for fiberglass by applying a coating based on perchlorovinyl resin, an organic solvent in combination with a blowing agent and then drying the coating at room temperature, characterized in that a 1: 1 mixture of butyl acetate and acetone is used as the organic solvent, a foaming filler — a phosphorus-borazo-containing oligomer previously obtained by reacting methylphosphite borate, ED-20 epoxy resin and a Ilina in a weight ratio of 2.5: 1: 2.5 in an amount of 2.5-7.5 parts by weight per 100 parts by weight coating, and the coating is applied in a layer 1 mm thick, and drying is carried out for 2 days.