RU2131448C1 - Elastic fireproofing material - Google Patents

Abstract

FIELD: fireproofing material technology. SUBSTANCE: invention proposes an elastic fireproofing material containing, mas. p. p./100 mas. p. p. of chloroprene rubber: oxidized graphite exhibiting the coefficient of expansion 50-400, 50-100; mixture of CaCO₃ + SiO₂ at mass ratio = 1:1, 35-45; and chloroparaffin at chlorine content 25-30 wt.-%, 40-60. Material has additionally 15 mas. p. p. of vulcanizing agents. Material exhibits high heat-insulating properties, enhanced elasticity and strength and can be used for fireproofing of different structures. EFFECT: improved quality and properties, simplified technology, reduced cost. 3 ex

Description

 The invention relates to a technology for producing flame retardant materials with high heat-insulating properties when exposed to high temperatures, and can be used to protect against fire of various designs.

Known fire retardant material containing at least 35 parts by weight oxidized graphite (OG) per 100 parts by weight a polymer binder based on natural or synthetic rubber latex. In addition, the material contains other flame retardants and fillers (compounds of Al, P, Mg, Ca, including CaCO ₃ ). Polychlorobutadiene latexes, nitrile butadiene and other latexes are used as a binder. Fire-retardant material is obtained by mixing latex and oxidized graphite with subsequent formation (EP, application N 0245779, C 08 K 3/04, 1987).

 The disadvantage of this fire-retardant material is the complexity of the process: multi-stage, associated with the need for thorough mixing of the components, the need to remove water contained in latex, the inability to achieve uniformity of composition and the introduction of a large amount of fire-retardant component, as well as insufficient elasticity and strength of the finished material.

 Known fire retardant material containing oxidized graphite and a polymeric binder (chlorinated rubber, polyurethane, polyesters, phenolic and epoxy resins, etc.). Based on this composition, paints and coatings with one or more solvents are prepared. Fire-retardant material can be made in the form of massive plates (PCT, application WO 91/11498, C 09 K 21/02, 1991).

 The disadvantage of this material is the use in its composition of phenolic or epoxy resins emitting harmful substances during fire, the use of various solvents, an insignificant (3-20 wt.%) Content of foaming agents, which does not provide a high fire retardant ability of the material.

 Known fire retardant material, which includes oxidized graphite with a degree of expansion of 10-40 and a polymer binder - a halogen-containing elastomer mixed with phenolic resin. For 100 parts by weight oxidized graphite use 100 wt. including a binder based on 10 wt. including polychloroprene and 50 parts by weight phenolic resin (Austrian patent N 330320, C 09 D 005/18, 1974).

 A disadvantage of the known fire-retardant material is the presence in its composition of a large amount of phenolic resin, which releases carcinogenic products under fire conditions, as well as the use of coarse-grained (1.5-3 mm) oxidized graphite with a low degree of expansion.

The closest is the known fire retardant material containing 25-60 wt.% Oxidized graphite. 5-25 wt.% Chloroprene latex (in terms of solid) and 5-25 wt.% Of a substance selected from the group: polyacrylonitrile, cellulose, phenol-formaldehyde resin, polyimides, etc. In addition, the material may contain various organic and inorganic additives, for example, chloroparaffins, silicates, silica, hydroxides of Al, Mg, Al carbonate, etc. From this material a coating with a thickness of about 2.5 mm is obtained, expanding when heated by 5-7 times. Oxidized graphite used in the composite is obtained by treating natural graphite with smoking HNO ₃ (US Patent N 5.232.976, class C 08 J 5/10, 1993).

 The disadvantage of this material is the use of phenolic resin in its composition, which releases harmful substances in fire conditions, as well as chloroprene latex, which requires very careful homogenization of the components, the need to remove water, the inability to achieve uniformity of composition and a low degree of expansion of oxidized graphite. In addition, the material does not have sufficient elasticity and strength, which limits the scope of its application and adversely affects its fire retardant ability.

 The objective of the invention is a fire retardant material with increased elasticity and strength, economical and technological in production and multifaceted in use.

This problem is achieved in that the proposed elastic fire-retardant material contains, by weight. hours:
chloroprene rubber - 100
oxidized graphite with a degree of expansion of 50-400 - 50-100
chloroparaffin with a chlorine content of 25-30 wt.% - 40-60
a mixture of calcium carbonate and silicon oxide in an equal weight ratio of 35-45
vulcanizing mixture - 15
To obtain the material using chloroprene rubber with a high crystallization rate (grades RNP, DKT, etc. (TU 6-01-925-74)). Said rubber is manufactured on an industrial scale, readily available and inexpensive. The selected rubber in combination with oxidized graphite provides fire protection for a wide range of combustible materials, while the organic component of the coating is not burned out due to the non-combustibility of chloroprene, which increases the performance of the coating by reducing the erosion of the expanded fire-retardant coating.

 The content of oxidized graphite (OG) is more than 100 wt.h. in a fire-retardant material leads to the fact that in a fire, the binder loses its frame and the material falls off very much, ultimately, the fire-retardant ability of the coating deteriorates significantly. The exhaust gas content is less than 50 parts by weight. it is also undesirable, since the material foams weakly and the insulating pad does not work efficiently, that is, in this case, the fire-retardant ability of the material also decreases.

 Oxidized graphite used in the present invention has a degree of expansion of 50-400. An increase or decrease in the degree of expansion of oxidized graphite is undesirable for the same reasons as changing its content in the composition of the material. Oxidized graphite can be obtained in various ways: by electrochemical oxidation in a solution of sulfuric or nitric acid; oxidation of graphite in a solution of conc. sulfuric acid in the presence of nitric acid, potassium dichromate, sulfuric anhydride or chlorine; processing graphite in fuming nitric acid or other known methods. After oxidative treatment, the product is washed with water to remove excess oxidizing reagents and the exhaust gas is dried under mild conditions. In addition, the oxidation treatment mode can be used to control the oxidation state of the graphite matrix and obtain oxidized graphite with the content of combined water and various functional groups up to 40-50 wt.%. Under the influence of a flame on such “oxidized” graphite, it foams, accompanied for a long time by the release of a large amount of a gas-vapor phase (water, carbon dioxide) that does not support combustion.

 Therefore, due to the use of this or that type of oxidized graphite, it is possible to vary widely the properties of the flame retardant material, such as the initial foaming temperature, the amount and composition of the released gases and vapors, the mechanical strength of the coating, its fire retardant ability, depending on the specific area of use of the material.

 The material also uses liquid flame retardant - chloroparaffin with a chlorine content of 25-30 wt.% (TU 6-01-16-90) in an amount of 40-60 wt.h. It is precisely such a content of said chlorine paraffin that is optimal and makes it possible to efficiently process fire-retardant material in a worm syringe machine, which makes it possible to produce a rubber fire-retardant profile of various configurations with high elasticity and high fire resistance. Thus, the introduction of chloroparaffin with a content of 25-30% chlorine - a combustion inhibitor brings an additional positive effect.

It is proposed to use a mixture of CaCO ₃ SiO ₂ = 1: 1 as an inorganic additive. With a decrease in the content of the mixture of the specified composition less than 35 wt.h. significantly increases the residual elongation of the flame retardant material, and with an increase of more than 45 parts by weight the modulus of the rubber material increases. Both of these factors lead to a deterioration in the elasticity of the fire retardant composite, a loss of mechanical strength, and a decrease in fire retardant ability. CaCO ₃ and silicon oxide are active fillers that enhance the physicochemical characteristics of the material due to its structuring.

In the proposed material, you can use 15 wt.h. vulcanizing mixture. For the specified type of rubber, the following vulcanizing mixtures can be used:
1). potassium stearate - 2-5 wt. h

 oxides of Mg and Zn in an equal mass ratio of 12-15 wt.h.

 2). N, N '- difurfurylthiourea - 1-3 wt.h.

 oxides of Mg and Zn in an equal mass ratio of 12-15 wt.h.

 3). aldehyde accelerator (833) - 2-4 parts by weight

 lead litharge - 12-15 parts by weight

 4). Zn oxide - 5-8 parts by weight

 Mg oxide - 6-10 parts by weight

 Tiuram D - 0.8-1.5 parts by weight

 guanide F - 0.5-1.2 parts by weight

 sulfur - 0.8-1.2 parts by weight

 The most favorable conditions for vulcanization of the proposed material provides the last vulcanizing mixture in the following mass ratio of the above components 7: 10: 1: 1: 1.

We used natural graphite with a fineness of 0.2 mm GT grade (GOST 4596-75). Identification of the obtained products was carried out by the method of XRD and chemical analysis. The degree of exhaust gas expansion is estimated as the volume (in cm ³ ) of 1 g of foamed exhaust gas in the muffle at 900 ^° C. Physico-mechanical characteristics of the material were evaluated according to standard methods, fire tests were carried out in accordance with the requirements of ST SEV 1000-78 "Method for testing building structures for fire resistance" and ST SEV 3974-83 "Doors and gates. Fire test method." The material according to the invention has a fire resistance of 60-70.

Example 1
100 g of RNP brand chloroprene rubber is placed on rollers and plasticized for 2-3 minutes at room temperature. A hitch of rubber after rolling turns into a thin cloth (skin) with a thickness of about 1 mm. Then, successively in small portions, 40 g of chloroparaffin with a chlorine content of 25 wt.%, 35 g of a mixture of CaCO ₃ : SiO ₂ = 1: 1, 75 g of oxidized graphite with an expansion ratio of 200 and 15 g of vulcanizing mixture are successively mixed in small amounts to a homogeneous rubber masses. After that, the rubber mixture is processed on a single-screw syringe machine to obtain an endless profile of the desired section (for example, P, P, □, D-shaped), followed by vulcanization in a steam boiler at a temperature of 150 + 5 ^o C.

The result is an elastic fire-retardant material in the form of a U-shaped profile (wall thickness of about 1 mm) with a density of 1.35 g / cm ³ , tear resistance of 155 kgf / cm, relative elongation of 350%, residual elongation of 15%. Elongation stress by 200% (module) 70 g / cm. The degree of expansion of the material is 5.3 times. Fire resistance 70.

Example 2
The process of example 1 is carried out, but 50 g of exhaust gas with a degree of expansion of 400, 45 g of a mixture of CaCO ₃ : SiO ₂ = 1: 1, 60 g of chloroparaffin with a chlorine content of 30 wt.% And 15 g of vulcanizing mixture are used per 100 g of chloroprene rubber .

The result is an elastic flame retardant material, for example, in the form of a □ -shaped profile with a wall thickness of 0.95 mm with the following characteristics:
density - 1.31 g / cm ³
tear resistance - 170 kgf / cm
elongation - 410%
residual elongation - 14%
elongation stress by 200% (module) - 78 kgf / cm
expansion ratio - 4.6
fire resistance - 61
Example 3
The process is carried out as in example 1, but 100 g of exhaust gas with an expansion ratio of 50, 40 g of a mixture of CaCO ₃ : SiO ₂ = 1: 1, 50 g of chloroparaffin with a chlorine content of 30% and 15 g of vulcanizing mixture are used per 100 g of chloroprene rubber.

The result is an elastic fire-retardant material in the form, for example, of a P-shaped profile with a wall thickness of 1.05 mm with the following characteristics:
density - 1.42 g / cm ³
tear resistance - 138 kgf / cm
elongation - 220%
residual elongation - 26%
elongation stress by 200% (module) - 53 kgf / cm
expansion ratio - 5.9
fire resistance - 63
From the above examples it follows that the proposed material has high physical and mechanical characteristics (elasticity and strength), due to this, it is possible to obtain profiles of any given section from this material. This circumstance is important in the protection of complex structures.

 The fire resistance of the proposed material is not inferior to the best international standards.

Claims (1)

An elastic flame retardant material containing oxidized graphite, chlorine paraffin, inorganic additives and a polymeric binder, characterized in that it contains oxidized graphite with an expansion ratio of 50 to 400 as oxidized graphite, and it contains chloroparaffin with a chlorine content of 25 to 30 wt.% , as a polymeric binder, chloroprene rubber, as inorganic additives, a mixture of calcium carbonate and silicon oxide in an equal weight ratio and a curing mixture in the following ratio of components, as.ch .:
Chloroprene Rubber - 100
Oxidized graphite with a degree of expansion of 50 - 400 - 50 - 100
Chloroparaffin with a chlorine content of 25 - 30 wt.% - 40 - 60
The above mixture of calcium carbonate and silicon oxide - 35 - 45
Vulcanizing mixture - 15