RU2844975C1 - Method of modifying and dyeing aramid fibre - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method for dyeing meta- or para-aramid fibres, involving introduction of a metal-containing dye of formula (I), where M is a metal ion selected from a zinc or copper cation; R is CONH₂ or COCL; in an aprotic amide solvent at the step for synthesis of meta- or para-aramid fibre or after synthesis of meta- or para-aramid fibre, wherein the dye is taken in amount of 0.5-2.0 wt. % of polymer weight. Further, the coloured meta- or para-aramid fibre is formed from the solution using a wet or dry-and-wet method, followed by washing, drying and thermal treatment.

EFFECT: disclosed method enables to obtain uniform and intense paint blue-green colours, resistant to treatment with aqueous and organic solutions, to abrasion while maintaining high physical and mechanical properties.

4 cl, 4 tbl, 4 ex

Description

AREA OF TECHNOLOGY

The invention relates to the field of chemistry and chemical technology for producing heat-resistant aramid threads modified during synthesis, which have found wide application in various areas of industry, with an organometallic dye.

LEVEL OF TECHNOLOGY

Aramid fibers have a natural yellowish color and a high glass transition temperature, which makes them poorly permeable to dyes under normal dyeing conditions. The fiber structure is formed during their production and is finally fixed at the stage of drying and heat treatment.

High physical, chemical, thermal and ballistic properties of aramid fibers allow their use in protective clothing. In this regard, the process of dyeing aramid fibers and fabrics requires providing intensive, uniform and stable dyeing, while maintaining the functional characteristics of the textile. Dyeing aramid fabrics is a complex task due to their dense structure, high degree of polymer crystallinity and low content of functional groups that can interact with the dye.

To facilitate the dyeing of aramid fabrics, it is possible to dye the polymer solution before the formation of the thread structure, and then form the dyed threads.

The paper [Patent of the Russian Federation No. 2744118 Lakunin V.A. et al. Method for dyeing aramid fiber, published 02.03.2021., SPK D06M 13/298; D06M 13/402; D06P 1/6426] proposes a method for dyeing fiber with acidic metal-containing dyes, with the general formula Me(-O-)2Kp(-SO ₃ Na)n, in an amount of 0.5-5.0% of the polymer weight. The invention proposes to use anionic metal complex azo dyes. The presence of active metals in the composition of these azo dyes and their possible water solubility can cause acute and chronic toxicity during the process of forming and processing the fiber in the case of the release of microquantities of the dye; the presence of sulfo groups should have a favorable effect on the solubility of these dyes in water [Szymczyk M., Freeman H. Metal-complexed dyes // Rev Prog Color. - 2004. - V. 34. - №1. - P. 39e57].

There are methods for dyeing aramid fibers during their synthesis. One of these methods is described in the patent [RF No. 2210649, Volokhina A.V. et al. Published 20.08.2003, IPC: D06P 3/04, D06P 3/24, D01F 8/08.] To form fiber from a solution of aprotic amide-containing solvents, a mixture of polymeric materials consisting of aromatic polyamide and polyacrylonitrile is used. The content of the latter varies from 1.5 to 20 mass percent. Then the mixture is heat treated at a temperature of 240 to 350°C for 20 minutes. As a result, the aramid fiber is dyed dark brown or black, while its strength characteristics not only do not deteriorate, but in some cases improve. A significant disadvantage is that heat-setting releases toxic volatile substances.

Batch and continuous methods of dyeing aramid fibers using intensifying agents of various chemical natures have found wide application. The work [Nechwatal A., Rossbach V. The carrier effect in the m-aramid fiber/cationic dye/benzyl alcohol system // Textile research journal Vol. 69, Is. 9, Sep. 1999, 635-641] shows the efficiency of using benzyl alcohol, acetophenone, dimethylacetamide, and dimethyl sulfoxide in dyeing meta-aramid fibers with cationic dyes. It is proposed to use a cationic dye in an amount of 2% of the fiber weight and benzyl alcohol with a concentration of 70 g/l for dyeing from an aqueous solution in the presence of 20 g/l sodium nitrate and 2.5% acetic acid with a bath modulus of M = 20. Dyeing is carried out on batch-type devices for 60 min at 125°C. The main disadvantage of the proposed method is the deterioration of strength and tensile characteristics (by 18%).

A process for dyeing or treating aramid fibers with flame retardants, as well as simultaneously improving the flame retardant properties of poly(m-phenylene iso)-phthalamide fibers, is described in [US Patent No. 6840967. Riggins P., Hansen J. Dye diffusion promotion for aramids, published 11.01.2005, IPC: D06P 1/64, D06P 3/24, D06P 3/26]. The process includes the following steps: introducing the fiber into a dyeing solution containing a sufficient amount of dye and selected dye diffusion promoters and, optionally, at least one flame retardant, especially chloroalkyl diphosphate esters such as Antiblaze 100, also containing sodium nitrate, then heating the fiber and solution at a certain temperature and for a sufficient time to dye and treat the fibers with flame retardants (if a flame retardant is present). This method provides an improvement in fire protection indicators (FI) by 3-20%.

Preliminary treatment of aramid fibers with liquid ammonia increases their ability to interact with basic dyes [Nicolai M., Nechwatal A. The swelling effect of liquid-ammonia in the dyeing of aramid // Journal of the society of dyers and colorists Vl. 110, Is. 7-8, Jul-Aug 1994, 228-230]. The proposed method for removing liquid ammonia is important for the correct course of this process. Treated and dyed aramid fibers demonstrate a level of stability similar to fibers dyed with traditional basic dyes. However, increased dyeability leads to a decrease in physical and mechanical strength.

Similar to the proposed method is a method of modifying the fiber by carrying out a reaction between aramid fiber and adipic acid chloride or benzoic acid chloride [Yoo Hj., Ravichandran V., Ovendorf Sk. Pretreatments for improving the dyeability of p-aramid fiber // Textile research journal Vl. 64, Is.7, Jul.1994, 423-426]. This method improves the dyeability of the fiber, but requires very labor-intensive preparation. First, the fiber is treated with DMSO, only then is the metallation reaction carried out and the subsequent reaction of introducing adipoyl chloride, benzoyl chloride or vinyl benzyl chloride. The grafted fabrics were repeatedly washed with acetone and distilled water, extracted with acetone in a Soxhlet apparatus for 3 hours and dried for 2 hours at 100°C.

A similar method is proposed in the works [Manyukov E.A. Justification and development of a rational technology for dyeing domestic heat-resistant arlan fiber. - 2005], [Patent of the Russian Federation No. 2255160, Method for dyeing metapara-aramidbenzimidazole fiber, E.A. Manyukov, published 27.06.2005, IPC: D06P 3/04, D06P 3/24]. First of all, the Arlan meta-aramid fiber is pre-treated with a special mixture containing a solvent, dimethylacetamide, or dimethylformamide, or dimethylsulfoxide, or a mixture thereof, a lower methyl alcohol, or ethyl alcohol, or ethylene glycol, or glycerin, or another, and/or water in various proportions at 18-20°C for 5 to 60 minutes, with or without subsequent rinsing. This is followed by dyeing with dispersed or cationic dyes in a periodic manner at boiling temperature for 30-60 minutes, followed by rinsing with warm and cold water for 10-15 minutes. This method provides rich and durable colors. However, it has a disadvantage associated with the use of toxic and flammable substances. For example, ethyl and methyl alcohols are highly flammable, and the latter is a strong poison. Dimethylacetamide, dimethylformamide and dimethylsulfoxide are toxic substances of the third hazard class (maximum permissible concentration of 10 mg/ ^m3 ). According to the prototype, the compositions create unfavorable working conditions during the preparation of the bath for preliminary treatment, maintenance of dyeing equipment and thermal treatment of the material. Moreover, the structurally bound polar solvent remains on the fiber after dyeing and washing and can release toxins during use.

In the work [Patent of the Russian Federation No. 2362851, Method of dyeing aramid fibers. Mikhailovskaya A.P. et al., published 27.07.2009, IPC: D06P 3/04, D06P 3/24]. A method for producing dyed heat- and fire-resistant aramid fibers is proposed. The method consists of pre-treating the fiber in a bath using an intensifier of the composition (wt. %): gelatin - 20-25, complex salt based on aluminum oxide - 1-3, acetic acid - 3-4, water - the rest, after which the aramid fiber is dyed with acid dyes in a bath while boiling the composition (wt. %): acid dye - 2.5-10, acetic acid - 3-4, water - the rest. This method allows to obtain uniform and intense colors of a wide color range, resistant to washing and friction while maintaining high physical and mechanical properties. In addition, it increases the oxygen index and improves working conditions due to the exclusion of toxic substances.

The technical problem that has not been solved in the prior art is the deterioration of the physical and mechanical properties of the fiber when using known dyes used in the technology of dyeing aramid fibers.

DISCLOSURE OF INVENTION

Technical result

The author of the present invention has unexpectedly discovered that the use of a metal-containing dye of formula (I)

where M is a metal ion selected from zinc or copper cations: R is _CONH2 or COCl; in the process of synthesizing meta- or para-aramid fiber, it allows obtaining uniform and intense colors of blue-green color range, resistant to treatment with aqueous and organic solutions, as well as resistant to abrasion, while maintaining high physical and mechanical properties: static modulus of elasticity, tensile load, etc.

Thus, the technical result of the present invention is

- obtaining uniform and intense colors of the blue-green color range;

- the paint is resistant to treatment with aqueous and organic solutions;

- the paint is resistant to abrasion;

- the paint retains high physical and chemical properties.

- the possibility of carrying out dyeing both at the stage of synthesis of meta- or para-aramid fiber, and after the completion of the synthesis of meta- or para-aramid fiber.

A significant difference of the claimed method is dyeing at the stage of polymer synthesis or after completion of polymer synthesis with a metal complex dye of formula (I), which, due to the presence of active amide and/or acid chloride groups, interacts with polymer molecules in the reaction mass, is not washed out during polymer molding and retains its coloristic properties at all stages of production while maintaining high physical and mechanical properties.

The proposed invention sets the technical task of eliminating a number of shortcomings of the previous levels of technology. Environmental friendliness and technological effectiveness of the method are ensured: no mixture is required to activate the fiber or intensify the color, no change in the existing process is required, for example, boiling the fiber in a dye solution. The dye is not washed out, chromium salts and other toxic metals are not used. Good solubility of the pigment in the organic solvent used allows for obtaining an intense and uniform color. There is no transfer of the dye to the precipitation bath.

Method of dyeing fiber

The present technical problem is solved and the said technical results are achieved thanks to a method for dyeing meta- or para-aramid fibers, which includes the introduction of a metal-containing dye of formula (I)

where M is a metal ion selected from zinc or copper cation; R is _CONH2 or COCl;

in an aprotic amide solvent introduced into the reaction mixture at the stage of synthesis of meta- or para-aramid fiber or after completion of the synthesis of meta- or para-aramid fiber, while the dye is taken in an amount of 0.5-2.0 wt. % of the polymer mass.

This is followed by the formation of dyed meta- or para-aramid fiber from the solution using a wet or dry-wet method, followed by washing, drying and heat treatment.

In a preferred embodiment, the aprotic amide solvent is selected from the group consisting of dimethylacetamide, dimethylformamide, dimethylsulfoxide and N-methylpyrrolidone.

In another preferred embodiment, the polymer of the aromatic polyamide of the meta-, para-structure is synthesized from the following components:

30-70 mol. % 5(6)-amino-2-para-aminophenylbenzimidazole; 30-70 mol. % paraphenylenediamine or metaphenylenediamine and 98-100 mol. % terephthaloyl chloride or isophthaloyl chloride.

Fiber formation can be carried out from a solution using a wet or dry-wet method, followed by heat treatment at 180-400°C for 30-180 minutes. Organic molecules can be used as a dye: CAS Registry Number: 157060-19-0 (obtained according to the work doi: 10.1246/bcsj.62.3359), CAS Registry Number: 132613-06-0 (obtained according to the method CN 103772396 A), CAS Registry Number: 86143-17-1 (obtained according to the work doi:10.1246/bcsj.62.3359), CAS Registry Number: 160435-37-0 (obtained according to the work dok10.l111/j.1751-1097.1994.tb05112.x). In this case, dimethylacetamide, dimethylformamide, dimethyl sulfoxide can be used as an aprotic amide solvent, for example.

For the purposes of this invention, the term "spun-dyed aramid fibers" refers to filament fibers or filament yarns made from an aromatic polyamide which serves as a fiber-forming polymer. This copolymer contains at least 85% amide bonds (-CO-NH-) directly bonded to two aromatic rings.

In this study, the preferred aramid fibers are para-aramid fibers, especially poly(para-phenylene terephthalamide) fibers available under the trade name RUSAR from JSC NPP Termotex (RU). The fiber-forming polymer for poly(para-phenylene terephthalamide) fibers is obtained by polymerizing (mol:mol) para-phenylenediamine, 5(6)-amino-2-para-aminophenylbenzimidazole, and terephthalic acid dichloride.

Furthermore, suitable aromatic copolymers in which para-phenylenediamine and/or terephthalic acid are partially or completely replaced by other aromatic diamines and/or dicarboxylic acids are also well suited for the fiber-forming polymer within the scope of this invention.

The characteristics of the spin-dyed aramid fibers according to this invention determine their use in various fields where aramid fibers are used.

For the purposes of this invention, the term "solution spinning" refers to the process of "extrusion" - forcing a solution of a fiber-forming polymer through tiny holes in a spinneret to form continuous strands of semi-solid polymer.

The term "wet and dry-wet process" refers to a process where the spinning threads are completely immersed in a precipitation bath, and as the threads emerge, they are precipitated from the solution and hardened, or an air gap is created between the surface of the bath and the spinneret, respectively.

The term "heat treatment" refers to the thermal treatment of the resulting fiber under reduced pressure in a special apparatus.

The term "metal complex dye" is an organic dye based on a coordination complex consisting of a central atom or ion, which is usually metallic and is called the coordination center, and a surrounding array of bound molecules or ions, which in turn are known as ligands or complexing agents.

IMPLEMENTATION OF THE INVENTION

The present invention is further illustrated, but not limited, by the following examples.

Example 1. Coloring of the reaction polymer solution

A solution (20 wt.%) of zinc dye, [29H,31H-phthalocyanine-2,9,16,23-tetracarboxyamidate(2-)-N ²⁹ ,N ³⁰ ,N ³¹ ,N ³² ] in an aprotic solvent (dimethylacetamide, N-methylpyrrolidone) is introduced into a spinning solution containing a mixture of diamines 5(6)-amino-2-para-aminophenylbenzimidazole (70 mol%) and paraphenylenediamine (1.2155 mol / 30 mol%), the amount of dye is 0.5 wt.% of the mass of the resulting polymer, then terephthaloyl chloride (100 mol%) is introduced.

Aramid thread, formed by a dry-wet method from a polymer dyed in mass, is heat-treated at a temperature of 340-370°C for 120 minutes. The resulting thread has the following physical and mechanical characteristics:

Example 2

A solution (20 wt.%) of zinc dye, [29H,31H-phthalocyanine-2,9,16,23-tetracarbonyl tetrachloride(2-)-N ²⁹ ,N ³⁰ ,N ³¹ ,N ³² ] in an aprotic solvent (dimethylacetamide, N-methylpyrrolidone) is introduced into a spinning solution containing a mixture of diamines 5(6)-amino-2-para-aminophenylbenzimidazole (70 mol%) and paraphenylenediamine (1.2155 mol / 30 mol%), the amount of dye is 2.0 wt.% of the mass of the resulting polymer, then terephthaloyl chloride (98-100 mol%) is introduced.

Aramid thread, formed by a dry-wet method from a polymer dyed in mass, is heat-treated at a temperature of 340-370°C for 120 minutes. The resulting thread has the following physical and mechanical characteristics:

Example 3

A solution (20 wt.%) of copper dye [29H,31H-phthalocyanine-2,9,16,23-tetracarbonyl tetrachloride(2-)-N ²⁹ ,N ³⁰ ,N ³¹ ,N ³² ] in an aprotic solvent (dimethylacetamide, N-methylpyrrolidone) is introduced into a spinning solution containing a mixture of diamines 5(6)-amino-2-para-aminophenylbenzimidazole (75 mol%) and paraphenylenediamine (1.2155 mol / 25 mol%), the amount of dye is 0.5 wt.% of the mass of the resulting polymer, then terephthaloyl chloride (98-100 mol%) is introduced.

Aramid thread, formed by a dry-wet method from a polymer dyed in mass, is heat-treated at a temperature of 340-370°C for 120 minutes. The resulting thread has the following physical and mechanical characteristics:

Example 4

A solution (20 wt.%) of copper dye [29H,31 H-phthalocyanine-2,9,16,23-tetracarboxyamidate(2-)-N ²⁹ ,N ³⁰ ,N ³¹ ,N ³² ] in an aprotic solvent (dimethylacetamide, N-methylpyrrolidone) is introduced into a spinning solution containing a mixture of diamines 5(6)-amino-2-para-aminophenylbenzimidazole (70 mol%) and paraphenylenediamine (1.2155 mol / 30 mol%), the amount of dye is 2.0 wt.% of the mass of the resulting polymer, then terephthaloyl chloride (98-100 mol%) is introduced.

Aramid thread, formed by a dry-wet method from a polymer dyed in mass, is heat-treated at a temperature of 340-370°C for 120 minutes. The resulting thread has the following physical and mechanical characteristics:

Claims (10)

1. A method for dyeing meta- or para-aramid fibers, comprising: introducing a metal-containing dye of formula (I) where M is a metal ion selected from zinc or copper cations; R is _CONH2 or COCl; in an aprotic amide solvent at the stage of synthesis of meta- or para-aramid fiber, or after completion of the synthesis of meta- or para-aramid fiber, while the dye is taken in an amount of 0.5-2.0 wt. % of the polymer mass. 2. The method according to claim 1, wherein the method additionally includes forming the dyed meta- or para-aramid fiber from the solution using a wet or dry-wet method, followed by washing, drying and heat treatment. 3. The method according to claim 1, characterized in that the aprotic amide solvent is selected from the group consisting of dimethylacetamide, dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone. 4. The method according to item 1, characterized in that the polymer from an aromatic polyamide of a meta- or para-structure is synthesized from the following components: 30-70 mol. % 5(6)-amino-2-araaminophenylbenzimidazole, 30-70 mol.% paraphenylenediamine or metaphenylenediamine and the corresponding amount of terephthaloyl chloride or isophthaloyl chloride.