RU2422489C1 - Fire-retarding composition for metal structures - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a fire-retarding composition with intumescent action for metal structures. The composition contains a film-forming agent, hardener OSA-1, an ionic surfactant and thickener. The film-forming agent used is an aluminophosphate or aluminochromophosphate film-forming agent. The thickener used is crushed basalt fibre, glass microspheres or mixture thereof. The fire-retarding composition has improved process characteristics, particularly intumescence capacity at high temperatures.

EFFECT: use of the composition increases fire-retarding efficiency.

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Description

The invention relates to methods of fire protection of metal structures and can find application in industrial and civil engineering, in the production of fire-resistant products, as well as during preventive measures for fire protection of production facilities.

In recent years, metallophosphate compositions have been recognized as the most promising due to their high efficiency, relatively low cost, and ability to swell at elevated temperatures.

A known method of obtaining a flame retardant proposed in [RU No. 2277076, class. B27K 3/52, C09K 21/10]. It involves the mixing of aluminochromophosphate, a nonionic surfactant and polyamine [see RU 2228925, cl. С07С 211/13, 209/60], previously neutralized with phosphoric acid to a pH of 6.0-8.8, moreover, an aqueous solution of a product of the general formula is used as a polyamine

H ₂ [H ₆ N ₂ C ₂ ] _{n + 1} NCON [C ₂ N ₂ H ₆ ] _{m + 1} , where n = 0.1 and m = 0.1,

in the following mass ratio of components of aluminochromophosphate: nonionic surfactant: polyamine, equal to (20-90) :( 0.1-0.5) :( 10-80).

When processing wood products, this fire-retardant composition ensures their transfer to the first group of fire-retardant efficiency. Its disadvantages include an increased cure rate, depending on the ambient temperature, as well as a low viscosity, making it difficult to obtain layers of increased thickness during fire protection of metal structures.

Known [SU No. 883119, cl. C09D 5/18, C09D 3/54] a flame retardant intumescent coating composition comprising a film-forming agent based on urea-formaldehyde or melamine-formaldehyde resin, fiberglass, a porous filler, a solvent, and carbonizing additives (urea, melamine, etc.). Its significant disadvantages include reduced weather resistance of the used film-forming.

Compositions for fire retardant coatings are also known, involving the use of silicates and complex phosphates as film formers, which contain a porous and fibrous filler, a surfactant and other components [RU No. 94044272, class. C09D 21/14; RU No. 2084481, class C09D 1/04]. These compositions are characterized by a low coefficient of expansion at elevated temperatures, which leads to an increased consumption of compositions during flame retardant operations.

The closest in technical essence is the flame retardant composition of intumescent action described in [RU No. 2339671, class. C09K 21/10]. Its manufacture involves the mixing of metallophosphate and a composition comprising a hardener, ionic surfactant and a NOTEX rust converter, moreover, OSA-1 fire retardant composition, AM-1 amine modifier, amino alcohols and other amino compounds are used as hardeners, in the following ratio ingredients, wt.%: metallophosphate: hardener: ionic surfactant: “NOTEX”, equal to (40-90) :( 5-30) :( 0-15) :( 0-20).

When using this composition, it is necessary to apply several of its layers, which is caused by the reduced viscosity of the composition. As a result of this, the cost and timing of flame retardant work increase.

An object of the present invention is an intumescent type fire retardant composition having improved technological properties.

The task is achieved in that, along with the metal phosphate film-forming, hardener "OSA-1" and ionic surfactant, it contains a thickener that exhibits heat-insulating properties.

The essence of the proposed technical solution is a fire retardant composition for metal structures, including aluminophosphate or alumochromophosphate film-forming, hardener OSA-1, ionic surfactant and thickener, and basalt fiber, microspheres or their mixture are used as a thickener, in the following ratio of ingredients, wt.%: Film-forming: hardener: ionic surfactant: thickener equal to (50-75) :( 10-30) :( 3-10) :( 1-20).

When these reagents are mixed, a suspension is formed containing a low molecular weight urea-formaldehyde resin, polycondensation products of aluminophosphate or aluminochromophosphate and a thickener. In the process of its further curing, supramolecular structures are formed, which tend to swell at high temperature due to the removal of low molecular weight compounds - water, carbon dioxide, ammonia and formaldehyde.

Indeed, when a hardener and a surfactant are added to an acidic aluminum or aluminum chromophosphate, the pH of the mixture is set at a higher level than the initial metallophosphates, which causes a quick crosslinking of phosphate groups with the formation of a spatial network. On the other hand, at pH below 7, the components of the hardener "OSA-1" enter into the polycondensation reaction with the formation of urea-formaldehyde resin. This is favored by the presence in its composition of various methyl urea, prone to condensation in an acidic environment with the formation of gummy products. The role of ionic surfactants is to improve the wettability of the surface of the material (wood, metal) with a flame retardant.

The advantage of the proposed flame retardant is its ability to expand at elevated temperatures. This is due to intramolecular rearrangements in the hardener OSA-1 and aluminophosphate (alumochromophosphate), accompanied by the cleavage of low molecular weight substances, mainly water. The course of this process is confirmed by various physicochemical methods, including the results of thermal analysis. Intensive pore formation and raising of the fire-retardant layer prevent the effects of open fire and thermal radiation on the upper layers of wood or metal.

In contrast to the prototype, the number of layers applied to products to achieve the required coating thickness and degree of fire resistance is halved.

As the film-forming used aluminophosphate and aluminochromophosphate synthesized according to RU No. 2187478, class. C04B 12/02.

The resulting products had the following quality indicators:

Characteristic aluminophosphate aluminum chromophosphate the aluminum content in terms of Al ₂ O ₃ , wt.% 9.0-12.5 6.6-9.0 the chromium content in terms of Cr ₂ O ₃ , wt.% - 3.5-4.5 phosphate content in terms of P ₂ O ₅ , wt.% 32-37 35-39 density, g / cm ³ 1.55-1.70 1.60-1.75

Fire-retardant composition "OSA-1" was obtained by the method described by RU No. 2270752, class. B27K 3/52, C09K 21/12.

It provides for the condensation of urea-formaldehyde concentrate composition, wt.%:

urea 21-25 formaldehyde 54-60 water rest

with ammonia water taken in equimolar terms for formaldehyde and ammonia, when heated in a slightly alkaline medium in the presence of monoethanolamine, added together with ammonia water in an amount of 0.15 wt.% calculated on urea-formaldehyde concentrate, followed by the introduction of 5.2 wt.% urea calculated on 100 wt.% urea-formaldehyde concentrate, cooling and neutralizing the reaction mixture with phosphoric acid to a pH of 6.7.

Hardener grade OSA-1 had the following quality indicators:

the presence of free formaldehyde lack of pH 6.7 refractive index 1,412 density at 20 ° C, g / cm ³ 1.18 freezing temperature, ° С minus 15

As an ionic surfactant, we used PO-6 TS foaming agent of grades A and B, produced according to TU 0258-147-05744685 and which is an aqueous solution of triethanolamine salts of primary alkyl sulfates. Their content in the used product was 30 wt.%.

Evaluation of the insulating properties of fire retardant coatings was carried out according to the method developed by VNIIPO. The essence of the method is to determine the time of heating the unheated side of a sample of a metal plate to a critical temperature of 500 ° C during the tests, which are carried out according to the temperature regime, according to GOST 12.1.004-89.

The fire protection parameters of metal structures were determined according to NPB 236-97. Fire retardants for steel structures. General requirements. Methods for determining fire retardant efficiency.

The invention is illustrated by the examples given in the table.

From the description of the invention and the table shows that according to the claimed technical solution, it is possible to obtain flame retardant compositions of intumescent type, characterized by high flame retardant efficiency, improved ultimate compressive strength of the coating in comparison with the prototype. In contrast to the known composition, a decrease in the number of layers applied to products to achieve the required coating thickness and degree of fire resistance is also noted, which reduces the cost of fireproofing.

Properties of flame retardants according to the proposed method and prototype

Ingredient Prototype Examples one 2 3 four 5 Composition, wt.% aluminum chromophosphate - - - 65.0 73.6 - aluminophosphate 71,4 63.8 57.7 - - 73.3 Hardener OSA-1 21,4 19.1 17.3 17.0 18.3 10,2 Ionogenic surfactant PO-6TS grade B 7.2 6.5 5.8 8.0 7.0 3.0 Thickener: - basalt fiber ^x) , - 10.6 - 3.3 1,1 8.9 - microspheres of the brand MSVP-50 ^xx) - - 19,2 6.7 - 4.6 Composition properties The number of layers to obtain a coating thickness of 1 mm two one The time to reach a critical temperature of 500 ° C on a non-heated surface with a coating thickness of one mm, min 18.1 18,4 18.3 18.5 18.6 18.2 Compressive strength ^xxx) one 1.12 1.20 1.10 1,07 1,11 Fire retardant efficiency group according to NPB-238-97 III ^x) Shredded superthin fibers with a diameter of 3 microns and a length of 50-100 microns ^xx) Glass microspheres with a diameter of 20-160 μm, sizing with γ-aminopropyltriethoxysilane ^xxx) The ratio of the tensile strength of the cured composition to the prototype

Claims (1)

Fire retardant composition for metal structures, including aluminophosphate or aluminochromophosphate film-forming, hardener OSA-1, ionic surfactant and thickener, characterized in that basalt fiber, microspheres or their mixture are used as a thickener, in the following ratio of ingredients, wt. %: film-forming: hardener: ionic surfactant: thickener, equal to (50-75) :( 10-30) :( 3-10) :( 1-20).