RU2378427C1 - Method for modification of polyamide fibres - Google Patents

Abstract

FIELD: textile industry.

SUBSTANCE: treatment is carried out with composition, which contains the following components in wt parts: 20 borate of methyl phosphite, 1.3 of triethanolamine, 80 of water and 0.20-0.65 of 1% water solution of carboxymethylcellulose at 20°C for 1 min. Fibres are dried on air and thermostatted at 100°C for 30 min.

EFFECT: improved fire-resistance, water-resistance, strength and resistance to thermal-oxidative destruction of polyamide fibres, increased strength of polyamide cord joint to rubber on the basis of chloroprene rubber.

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Description

The invention relates to the textile industry, to methods for flame retardant processing of polyamide fibers, and can be used in aircraft, automotive, rubber industry and for other special purposes.

A known method of fire-retardant finishing of textile materials from cellulose fibers, which consists in impregnating them with a composition comprising the product of the interaction of nitrilotrimethylphosphonic acid with a nitrogen-containing substance and water at a temperature of 30-70 ° C for 3-10 s and squeezed to a wet gain of 80-90%. Next, the material is dried at 90-220 ° (Pat. 2184184 Russia, D06M 13/432; publ. 27.06.01).

However, this method requires drying the impregnated cord at high temperature and is intended only for materials made of cotton, linen and viscose fibers.

A known method of flame retardant processing of textile materials, which consists in impregnating samples of nylon fabric and cotton knitted fabric with a composition containing a derivative of chlorendic acid and an organic solvent, in a batch at 20 ° C for 5 minutes, followed by drying in air (Copyright certificate 953045 USSR, D06M 13/20; publ. 08.23.82).

However, this method uses a multicomponent modifying composition in conjunction with a solvent harmful to the environment and human health.

Closest to the invention in technical essence is a method for producing fire-retardant chemical fibers by grafting cellulosic or synthetic fibers from 5-7% aqueous solutions of phosphorus-containing monomer (Fakril-M) at a temperature of 80-90 ° C for 90-120 min using the redox system Fe ²⁺ -N ₂ About ₂ (Application for invention No. 93012912; publ. 09/20/96).

However, this method of obtaining flame retardant chemical fibers is time-consuming.

Objective: to develop a method for producing modified synthetic fibers that does not require complex hardware design, is not time-consuming and allows to obtain products based on them with increased fire resistance and physical and mechanical properties.

The technical result is to simplify the method of producing modified polyamide fibers, increase their fire resistance, strength, water resistance and resistance to thermal oxidative degradation, increase the bond strength of the polyamide fiber with rubber based on chloroprene rubber.

The technical result is achieved by the fact that the method of modifying polyamide fibers by treatment with a composition comprising a phosphorus-containing compound and water, followed by air drying and temperature control, the treatment is carried out by a composition containing in parts by weight of: methyl phosphite borate - 20, water - 80, triethanolamine - 1.3 and 1% aqueous solution of carboxymethyl cellulose at 20 ° C for 1 min, and thermostating is carried out for 30 min at 100 ° C.

It is established that the reason for the increase in fire resistance and resistance to thermal oxidative degradation of polyamide fibers is the formation of a thin fire-retardant film on the surface of the fibers, which inhibits their combustion due to the formation of a foamed layer with better thermal conductivity.

The increase in fiber strength is due to the localization of microdefects on its surface with an impregnating composition. Since microdefects are the root cause of the destruction of the fiber when exposed to external stresses.

The increase in water resistance is explained by the introduction of a 1% aqueous solution of carboxymethyl cellulose into the impregnating composition, which prevents the washing out of the impregnating composition from the surface of the fiber.

The adhesion of the polyamide fiber to the rubber increases, apparently due to the emergence of new polar functional groups on the surface of the fiber, which enter into physical interaction with chloroprene rubber.

Methylphosphite borate - was used earlier for flame retardant modification of cellulosic materials (RF Patent 2254341 C1, СВВ 15/05, publ. 06/20/05).

Triethanolamine (TU 6-02-916-79) is used as an absorbent of "acid" gases, as a raw material for the production of surfactants, in pharmaceuticals and cosmetics.

Carboxymethyl cellulose (TU 6-55-39-90) is used in synthetic detergents as a stabilizer, as a thickener for aqueous media.

This method can significantly simplify the modification of polyamide fibers. So to achieve a positive effect, it is not required to use multicomponent and highly concentrated flame retardants. The use of a 20% aqueous solution of methylphosphite borate is most optimal. A decrease in the concentration of methylphosphite borate does not allow the self-extinguishing effect to be achieved, and an increase in the concentration reduces the strength of the fibers.

With a decrease or increase in the content of triethanolamine in the flame retardant composition, the flame retardant and strength properties of polyamide fibers deteriorate, because the acidity of the medium changes.

With an increase in the content of a 1% aqueous solution of carboxymethyl cellulose in the impregnating composition, the fire resistance of the fiber decreases, and with a decrease in the strength of the polyamide fiber and the resistance to leaching of the impregnating composition from the surface of the fiber decreases.

When reducing the modification time of polyamide fibers less than 1 minute, the impregnating composition significantly reduces the fire retardant effect. An increase in the modification time of more than 1 minute is not advisable, because the degree of fire protection does not change.

It should be noted that this method of modification does not require complex hardware design.

The treatment is carried out as follows: the initial samples of polyamide fibers are treated with a composition containing a 20% aqueous solution of methylphosphite borate, triethanolamine and a 1% aqueous solution of carboxymethyl cellulose. The treatment is carried out for 1 minute at room temperature and dried to constant weight. Then the fibers are thermostated for 30 minutes at 100 ° C.

The invention is illustrated by the following examples.

Example 1. Samples of polyamide fibers (20 cm long) are placed for 1 minute in a 20% aqueous solution of methylphosphite borate previously neutralized with triethanolamine to ph 7 and containing 0.20 wt.h. 1% aqueous solution of carboxymethyl cellulose, followed by drying at room temperature to constant weight, then thermostat the fibers for 30 minutes at 100 ° C.

Examples 2-3 are carried out as in example 1, changing the content of a 1% aqueous solution of carboxymethyl cellulose.

Get impregnating compositions 1-3, the formulation of which is shown in table 1.

The obtained samples are tested for resistance to combustion (GOST 21793-76), tensile strength (GOST 20403-75), resistance to thermal oxidative degradation (studies were carried out at a temperature of 300 ° C for 30 minutes), water absorption (GOST 4650-65 ) The bond strength of the impregnated cord with rubber based on chloroprene rubber (F.F.Koshelev et al. General technology of rubber. - M .: Chemistry, 1978, p.85) was determined by the N-method (GOST 23785.7-89) on a RMI tensile testing machine -60. The results are shown in table 2.

The table shows that with a decrease in the content of a 1% aqueous solution of carboxymethyl cellulose, the physical and mechanical properties of the modified fibers improve. So when processing polyamide fiber flame retardant according to the recipe 1, the breaking load increases from 17.5 kgf to 37.6 kgf. In addition, modified fibers exhibit greater resistance to thermal oxidative degradation. The decrease in weight loss from 3.6% to 0.117% at 300 ° for polyamide fiber indicates the effective action of the flame retardant, as a coke formation catalyst during thermal oxidative degradation of the studied fibers. The use of this composition helps to increase the bond strength of the polyamide fiber with rubber from 3.2 kgf to 4.3 kgf when using the composition of recipe 1.

Table 1 Component The content of components, parts by weight, in the composition one 2 3 Methyl Phosphite Borate 20,0 20,0 20,0 Water 80.0 80.0 80.0 Triethanolamine 1.3 1.3 1.3 1% aqueous carboxymethyl cellulose solution 0.20 0.33 0.65

table 2 Type of test No impregnation Sample No. for examples one 2 3 Breaking load, kgf 17.5 37.6 21.5 27.6 Elongation mm 32,0 43.6 34.0 40.6 Water absorption,% 17.4 -7.0 -12.4 -13.6 Mass loss% 3.6 0.117 0,120 1,145 Fire resistance burns Self-extinguishing w / s 5 s Self extinguishing Do not ignite. Adhesion to rubber based on HC (H-method), kgf 3.2 4.3 3.9 3,5

The technical and economic effect obtained from the application of this modification method consists in the fact that its application can significantly increase fire resistance, strength, water resistance, resistance to thermo-oxidative degradation and adhesion to polyamide fiber rubber, does not require complicated hardware design, long processing time, which avoids multi-stage processing.

Claims (1)

A method of modifying polyamide fibers by treating with a composition comprising a phosphorus-containing compound and water, followed by drying in air and thermostating, characterized in that the treatment is carried out with a composition containing, by weight: methyl phosphite borate - 20, water - 80, triethanolamine - 1, 3 and 1% aqueous carboxymethyl cellulose solution - 0.20-0.65, at 20 ° C for 1 min, and thermostating is carried out for 30 min at 100 ° C.