RU2540645C1 - Composition for fireproof rubbers coatings - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: composition for fireproof rubber coatings contains chlorosulphurised polyethylene, toluene, phosphorus-containing compound. As phosphorus-containing compound it contains phosphorusboronnitrogen-containing oligomer, preliminarily obtained as a result of interaction of methylphosphite borate, epoxy resin ED-20 and aniline in weight ratio 2.5:1:2.5, with the following component ratio, wt.p.: chlorosulphurised polyethylene 15.0, toluene - 85.0, claimed phosphorusboronnitrogen-containing oligomer - 0.5-3.0.

EFFECT: invention makes it possible to ensure high fire protection of coating and increased adhesion to rubber.

3 tbl

Description

The invention relates to the field of production of flame retardant coatings based on a polymer binder and may find application in the rubber industry.

Known heat-protective coating containing a solution of chlorosulfonated polyethylene and stearic acid, graphite granules, chemically oxidized, ammonium salts or borax, or boric acid, or antimony oxide, or mixtures thereof, magnesium oxide, zinc oxide and diphenylguanidine (US Pat. Russia 2210582, C09D 123 / 34, C09D 5/18; publ. 08/20/2003).

However, this heat-protective coating is not intended for fire protection of rubbers.

A known composition for thermal barrier coatings, which includes an outer layer of chlorosulfonated polyethylene and at least one layer of a liquid sodium glass hardener - sodium silicofluoride, filler - fireclay, aerosil and glass filaments 5-10 mm long, inorganic pigment and crystalline hydrates (US Pat. 2162871, C09D 123/34, C09D 1/02, C09D 5/18; publ. 02/10/2001).

However, this composition does not have the necessary elasticity and has a complex composition.

A known composition based on chlorosulfonated polyethylene, including a filler, hardener and solvent, and additionally phosphorus-containing dimethacrylate (US Pat. 2171269, C09D 123/34; publ. 27.07.2001).

However, this composition is intended to produce hard coatings for floors and roofs.

Known fire retardant composition for combustible materials, which includes a solution of chlorosulfonated polyethylene in an organic solvent and liquid glass in the form of an aqueous solution of metal silicates or Quaternary ammonium (US Pat. Russia 2202577, C09D 5/18, C09D 1/04, C09D 123/34; publ. 04/20/2003).

However, this composition is intended for fire protection of wood.

Closest to the invention in technical essence is a composition for thermal barrier coatings containing chlorosulfonated polyethylene, toluene, thermally expandable graphite, zinc oxide, magnesium oxide, stearic acid, diphenylguanidine, ammonium phosphates and aluminum paste (US Pat. 2186813, C09D 123/34; publ. 10.08.2002).

However, this composition has a more complex formulation.

The task is to obtain a composition based on chlorosulfonated polyethylene for fire retardant coating of rubbers.

The technical result is the provision of high fire protection coatings and increased adhesion to rubber.

The technical result is achieved in that the composition for fire retardant coatings, including chlorosulfonated polyethylene, toluene, a phosphorus-containing compound, contains a phosphorus-boron-containing oligomer as a phosphorus-containing compound, previously obtained by reacting methylphosphite borate, ED-20 epoxy and aniline in a mass ratio of 2.5 : 1: 2.5, in the following ratio of components, parts by weight: chlorosulfonated polyethylene - 15.0, toluene - 85.0, said phosphorus-boron-containing oligomer - 0.5-3.0.

Chlorosulfonated polyethylene is the main film-forming in paint and varnish anticorrosive coatings (TU 6-55-9-90).

Toluene is an organic solvent (GOST 14710-78).

As a phosphorus-containing compound, a phosphorus-borazo-containing oligomer (FEDA) is used, previously obtained as a result of the interaction of 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, 1 mass part is loaded into the mixer. epoxy resin ED-20 and 2.5 parts by weight aniline, stirred until a homogeneous mass. Then 2.5 parts by weight of slowly are added dropwise. methylphosphite borate, 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 chlorosulfonated polyethylene flame retardant. In addition, a significant content of phosphorus and boron in the structure of the substance helps to achieve the maximum result without resorting to the use of large concentrations.

This composition allows to obtain coatings based on chlorosulfonated polyethylene with increased fire protection and adhesion to vulcanized rubber. The use of 15% solutions of chlorosulfonated polyethylene is most optimal. With increasing concentration, the viscosity of the solutions increases, which creates technological difficulties in the application of coatings and leads to a deterioration in the fire retardant properties of the coating.

The use of solutions of a lower concentration leads to an increase in the volume of compositions to obtain a coating of the required thickness. 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 and a decrease in adhesion to vulcanized rubber.

Fire retardant composition is prepared as follows.

First, a solution of chlorosulfonated polyethylene is prepared. Chlorosulfonated polyethylene and solvent - toluene are loaded into a flask with a stirrer and stirred for 4.5 hours until completely dissolved. Then the introduction of FEDA is carried out. The total cooking time is 5 hours.

The invention is illustrated by the following example.

FEDA is introduced into a flask containing a solution of chlorosulfonated polyethylene in toluene and the contents are mixed for 3-5 minutes until a homogeneous mass is obtained.

For comparative tests, 4 variants of the compositions were prepared (according to the method described in the example) and a composition according to the control example, the formulations of which are presented in table 2.

The composition is a beige liquid. It is well applied on a rubber surface.

Various FEDA contents have been investigated. The research results are shown in table 3.

The declared limits of FEDA are due to the fact that with an increase in these dosages, adhesion to vulcanized rubber decreases, and with a decrease, adhesion to vulcanized rubber decreases and fire protection decreases.

Comparative tests of the adhesion properties of coatings for all variants of the claimed composition and for example to vulcanized rubber based on nitrile butadiene rubber (SKN-18) and chloroprene rubber (Neoprene AC) and ethylene-propylene rubber (SKEPT-40) are given in Table 3.

The proposed coatings were tested for adhesive shear strength, achieved when kept under a load of 2 kg, at room temperature (20 ° C) for 24 hours. The data are presented in table 3, which shows that the best results were obtained using the composition 2-3.

Adhesive shear strength was determined on an MPC-250 tensile testing machine (RTM 12126-88).

The technology for bonding samples is as follows. One-time application of the prepared coating on the prepared surface, drying of the film at room temperature (20 ° C) for 1-2 minutes, after which the glued surfaces were pressed tightly.

The proposed coating provides a significant increase in the adhesion properties of vulcanized rubber compared with the control example. So, the adhesive strength at shear of the coating to vulcanized rubber based on Neoprene AC according to the control example is 0.22 MPa, and with the use of FEDA 0.39 MPa (composition 3).

In order to determine the effectiveness of the developed flame retardants, coatings were tested by exposing the treated specimen to vulcanized rubber to an open flame source. The thickness of the fire retardant coating is 1.0 mm. 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. Before measurements, coated samples are dried at room temperature for at least 24 hours.

The obtained samples are tested for resistance to burning (OST 1 90094-79), resistance to thermal oxidative degradation (studies were carried out at a temperature of 500 ° C for 10-30 minutes). The results are shown in table 3.

table 2 Component Test case The content of components in the composition, parts by weight one 2 3 four Chlorosulfonated Polyethylene 15.0 15.0 15.0 15.0 15.0 Toluene 85.0 85.0 85.0 85.0 85.0 FEDA - 0.5 1,0 2.0 3.0

From table 3 it is seen that the proposed coatings exhibit greater resistance to thermal oxidative degradation. For example, the presence of a coke residue of 32% at 500 ° C in the composition according to the recipe 4 indicates an effective fire retardant effect.

A study of resistance to fire shows that coating films die out after being taken out of a flame source.

Table 3 Test Metric for composition Test case one 2 3 four Adhesion to rubber based on SKEPT-40, MPa 0.39 0.44 0.49 0.45 0.41 Adhesion to rubber based on SKN-18, MPa 0.34 0.40 0.38 0.36 0.35 Adhesion to rubber based on Neoprene, MPa 0.22 0.34 0.35 0.39 0.34 Coke residue at a pyrolysis temperature of 500 ° C,% - 10 minutes 33 38 43 55 69 - 20 minutes 24 27 31 48 56 - 30 minutes 5 7 eleven 19 32 Fire resistance Is on Fades out Fades out Fades out Fades out

Thus, the introduction of FEDA into the composition provides high fire resistance of the coating and improved adhesion to rubbers based on various rubbers.

The technical and economic effect obtained from the use of this composition is that its use allows to increase the fire resistance of rubbers based on various rubbers.

Claims (1)

Composition for fire retardant coatings of rubbers, including chlorosulfonated polyethylene, toluene, phosphorus-containing compound, characterized in that it contains a phosphorus-boron-containing oligomer as a phosphorus-containing compound, previously obtained as a result of the interaction of methylphosphite borate, ED-20 epoxy resin and aniline in a mass ratio of 2.5: 1: 2.5, in the following ratio of components, mass. hours:
Chlorosulfonated Polyethylene 15.0 Toluene 85.0 The specified phosphoroborozotol-containing oligomer 0.5-3.0