RU2191232C1 - Process of manufacturing wool from cellulose fibers - Google Patents

Abstract

FIELD: textile industry. SUBSTANCE: in a process of manufacturing wool, for example medicinal wool, from flax fibers, the latter are first subjected to mechanical treatment and then chemical treatment in alkaline medium in presence of sodium hypochlorite at 18- 25 C followed by washing, whitening through oxidative boiling at silica/alkali ratio of solution at least 0.5 and total alkalinity of solution 3.0 to 7.5 g/l, and final washing. Treatment of fibers in alkaline medium and/or whitening is conducted in presence of complexing compound, in particular a derivative of carboxylic acid and/or phosphonic acid with number of phosphonic groups at least 2. After that, fibers are subjected to souring, washing, and garneting. EFFECT: simplified process and reduced its danger, increased qualitative characteristics of finished product. 3 cl, 2 tbl

Description

 The invention can be used in the textile industry in the manufacture of cotton wool from cellulose fibers.

State of the art
The strategic task of ensuring the release of medical supplies, regardless of the price situation for imported cotton and its quality, is solved using domestic bast fibers, primarily linen. A prerequisite for its implementation is the development of highly efficient, economical and environmentally friendly methods of cleaning and razvolnenie technical fibers, which allow to obtain high-quality materials with valuable medicinal properties from the "low-grade" short flax and flax spinning waste and significantly expand the raw material base for enterprises producing cotton wool and products for it basis.

 Periodic and continuous are known [Finishing of cotton fabrics / Ed. B.N. Melnikova. M .: Legprombytizdat, 1991. - C.96, 98] methods for producing medical cotton wool from cotton fibers. These methods combine the chemical treatment of fibers with alkaline / alkaline peroxide and alkali reduction / alkaline peroxide systems with a complex of mechanical effects, including cleaning, loosening, mixing of fibers, drying, scuffing and scratching [G.A. Weinstein. Handbook of cotton production. M .: Light industry, 1972. - C.153].

 The disadvantages of these methods are, respectively, the high energy intensity of the processes and low quality indicators for medical cotton wool, namely low whiteness, capillarity, and absorption capacity.

 There is also a known method of producing cotton wool, in which the chemical treatment of cotton fiber with alkaline hypochlorite solutions is carried out successively by boiling in boilers and by bleaching in vats. [G.A. Weinstein. Handbook of cotton production. M .: Light industry, 1972. - C.112]. However, this method is very complex, time-consuming, does not always provide good quality cotton wool and, moreover, is less environmentally friendly in comparison with alkaline peroxide.

 A known method of producing wool from mechanically peeled flax fiber [US Pat. RF N2104358]. It is carried out by alkaline cooking in the presence of a reducing agent and bleaching with hypochlorite in two stages at its concentrations of 1-2 and 2-3 g / l at pH 6-9 and 7-10, respectively, with intermediate washing, acidification between stages, as well as acidification washing after bleaching.

The disadvantages of the method are a high degree of destruction of cellulose and low environmental friendliness of the process. The technology provides a twofold increase in the consumption of chlorine-containing solutions for processing, which naturally then enter the wastewater. Depending on the volume of digesters, the increase reaches 5-10 m ³ . In addition, impregnation with a solution of hypochlorite of acidified, not washed tissue, as well as its acidification immediately after treatment with hypochlorite (without intermediate washing) contribute to the release of corrosive and toxic decomposition products of hypochlorite.

Closest to the claimed is a method of manufacturing cotton wool from flax fiber (short, tow - waste flax production) [Pat. RF N2078163]. It is carried out by carrying out the following operations:
I - preliminary machining, including:
- processing of flax fiber on baking and cleaning units;
- razvolokanie on carding machines to a thickness of a single fiber of 0.3-0.4 Tex;
II - chemical treatment, including:
- processing of fibers in an alkaline medium, carried out by processing in a solution containing, g / l: caustic soda - 7.2, soda ash - 1.2, laundry soap 60 - 0.4, wetting agent 0.1 at a temperature of 130-140 ^o With and a pressure of 3-4 atm for 180-210 min;
- acidification:
- flushing;
- whitening with a composition containing, g / l: sulfuric acid 4.0, sodium hypochlorite (assuming active chlorine) 2.8;
- acidity;
- washing in rake-type washing machines;
- two washes in cold water at 15-20 ^o C for 25-30 minutes;
- spin to a moisture content of 120-130%;
III - release, including:
- loosening on a ripper of wet fiber RM-240-02;
- drying to a moisture content of 12-17%;
- scuffing on the TB-2 and TB-3 scutching machine;
- carding on a carding machine brand CVI-600 to a single fiber thickness of 0.15-0.2 Tex.

The disadvantages of the method are the following:
1. The complexity, the danger of the process due to the duration of operations (180-210 min), carried out at temperatures of 130-140 ^o C, due to the use of acidic solutions of sodium hypochlorite and two stages of acidification;
2. High loss of fiber mass due to harsh conditions of alkaline treatment and destruction of cellulose due to the use of acidic solutions of sodium hypochlorite and the use of two stages of acidification;
3. High yield of short fibers due to harsh chemical processing conditions of initially short complexes formed when flax is pulled to a linear density of 0.3-0.4 tex;
4. Low environmental and toxicological safety of the process and the resulting medical product due to the release of corrosive and toxic decomposition products of hypochlorite at low pH values;
5. High energy intensity of the process.

SUMMARY OF THE INVENTION
The objective of the invention is to find a simpler and more economical way to obtain high-quality medical cotton wool.

The problem is solved by a method of manufacturing cotton wool from cellulose fibers, including pre-machining them, chemical treatment by treating the fibers in an alkaline medium, washing and bleaching, acidification, washing and subsequent saponification, in which the processing of fibers in an alkaline medium is carried out in the presence of sodium hypochlorite at 18 -25 ^o C, oxidative bleaching is carried out by digestion with an alkaline silicate solution module of not less than 0.5, a total alkalinity of the solution 3,0-7,5 g / l, washing the chemical treatment prov they are used immediately after processing the fibers in an alkaline medium and after bleaching, and when processing fibers in an alkaline medium and / or bleaching, a complexing compound is used - a derivative of carboxylic and / or phosphonic acid with a number of phosphonic groups of at least 2. Hypochlorite is used at a concentration of 2, 3-3.5 g / l, and the complexing compound is 0.1-5.0 g / l.

The invention has the following advantages:
1. Simplification and reduction of the danger of the process due to a decrease in the temperature of the treatments and the exclusion of the use of acidic solutions of sodium hypochlorite. This prevented the release of corrosive and toxic decomposition products;
2. Reducing the loss of fiber mass, since processing is carried out at a temperature not exceeding 98 ^o C and reducing the number of technological operations;
3. The low yield of short fibers due to a decrease in the degree of preliminary flax dispersion and the use of milder conditions for its chemical ennoblement;
4. Improving the environmental and toxicological safety of the process and the target product;
5. The reduction of energy consumption due to the exclusion of operations conducted at a temperature of 130-140 ^o C.

 In addition, an additional advantage is that the increased whiteness of the resulting product eliminates the use of optical brighteners, even when producing high-quality eye cotton.

 Vata, obtained by the proposed method, meets the requirements of GOST, the requirements for cotton wool hygienic and surgical. It is characterized by high whiteness of 76-78%, moisture absorption of 24-27 g / g of fiber, uniformity of composition, lack of clogging (in the case of flax wool), is easily stratified into parallel layers. The mass fraction of short fibers does not exceed 0.1%, the content of fatty and waxy compounds is 0.2-0.4%, sulfate salts - 0.02%, chloride - 0.004%, calcium - 0.06%. Ash content varies between 0.2-0.4%. Foreign impurities, needles, slivers are absent, the reaction of the aqueous extract is neutral, the content of reducing substances is traces. Weight loss for various fibers is 7-20%.

Information confirming the possibility of carrying out the invention
As cellulose fibers, you can use cotton and flax fibers (tow, short, shake, wet flax spinning waste);
- use the following chemicals:
sodium hypochlorite NaClO (sodium hypochlorite) (GOST 11086-81) - a clear greenish-yellow liquid without precipitate and suspended particles, prepared at the enterprises of the chemical or textile industry, containing active chlorine up to 185 g / l (at the time of preparation of sodium hypochlorite);
sodium silicate Na ₂ SiO ₃ (liquid sodium glass) (GOST 13078-81) - a thick yellow or gray liquid without mechanical impurities visible to the naked eye, containing from 28.5 to 33% silicon dioxide (SiO ₂ ) and from 10- 12% sodium oxide (Na ₂ O). Density from 1.36 to 1.50;
sodium metasilicate Na ₂ SiO ₃ • 9H ₂ O (TU-6-18-161-82) is a white or yellow microcrystalline product containing 18.5-20% silicon dioxide (SiO ₂ ) and 20-20.5 sodium oxide ( Na ₂ O); completely soluble in water at room temperature. Sodium metasilicate analysis is carried out according to the methods used for sodium silicate;
sodium hydroxide NaOH (technical caustic soda) (GOST 2263-81) - a thick liquid or solid product produced in the form of flakes, granules, etc .;
soda ash Na ₂ CO ₃ (sodium carbonate or sodium carbonate) (GOST 10689-73 and 5100-74) - white crystalline powder. Depending on the production method (from nepheline raw materials - GOST 10689-73 or synthetic - GOST 5100-74) soda ash contains from 91 to 99% sodium carbonate. In humid air, anhydrous soda ash turns into solid lumps, but water absorption is negligible. Solubility of sodium carbonate (in g per 100 g of water): at 20 ^o С - 21.5, at 100 ^o С - 45.5;
hydrogen peroxide H ₂ O ₂ (GOST 175-81) is a colorless liquid produced in the form of a solution of two grades: technical and medical, with a concentration of 27.5-31.0% (weight). Peroxide is transported and stored in tanks and other aluminum containers made of A0 and A5 aluminum with an aluminum content of at least 99.3%, as well as in glass bottles with a capacity of not more than 65 liters. Store at a temperature not exceeding 30 ^o With the exception of direct exposure to sunlight;
magnesium salts, for example magnesium chloride MgCl ₂ • 6H ₂ O (technical) (GOST 7759-81) - a solid alloy of the magnesian salt of hydrochloric acid containing at least 96% magnesium chloride hexahydrate. Crystals of magnesium chloride are very hygroscopic, disperse in air, soluble in water and alcohol;
sulfuric acid H ₂ SO ₄ (GOST 2184-79 and 667-81) - a colorless or yellowish liquid with a density of at least 1.83;
a derivative of phosphonic or carboxylic acids with a number of phosphonic groups of at least 2, for example, GF, NTF, etc. These compounds, their salts or compositions based on them form complexonates of copper, iron and manganese, stable in an alkaline environment (pH> 1) at high temperatures (100 ^o C) and inert with respect to hydrogen peroxide. A decrease in the number of phosphonic groups in the structure of a compound, for example, IDUMP, reduces the effectiveness of its deactivating effect;
- glycine-dimethylene phosphonic acid (HF) N [(CH ₂ COOH) (CH ₂ PO ₃ H ₂ ) ₂ ] is a colorless crystalline powder, readily soluble in water (molecular weight 263);
- nitrilotrimethylene phosphonic acid (NTP) N [CH ₂ P (О) (OH) ₂ ] ₃ - (TU 2499-347-05763441-2000) - a colorless crystalline powder, readily soluble in water, acids, alkalis (molecular weight 299);
imino-diacetic-methylenephosphonic acid (IDUMP) - N [(H ₂ COOH) ₂ (CH ₂ PO ₃ H ₂ )] is a colorless crystalline powder, readily soluble in water (molecular weight 227);
surfactants - used as a wetting agent. These are anionic and nonionic compounds with a wetting, washing and emulsifying ability, available in the form of solutions, pastes, etc. domestic and foreign manufacturers, for example, Ivadet (TU 2484-171-05744685-99) - a composition based on anionic and nonionic surfactants, which is a moving mass from light yellow to yellow, with enhanced degreasing properties, with a mass fraction of active substance not less than 80%, pH of a 10% solution of 5-8, foaming ability of a solution with a concentration of 1 g / l - not more than 190 cm ³ .

The method is implemented by sequentially carrying out the following operations:
I - preliminary machining. It is carried out for each type of fiber on equipment traditionally used for this fiber; the flax fibers are pulled up to the linear density provided by this equipment, for example, cotton is subjected to cleaning and loosening operations on aggregates;
short flax fiber is processed on lines providing cleaning, loosening, scuffing, carding of the fibers to their linear density of not more than 2.0 tex;
Wet flax spinning waste (gum) before scratching is treated with plucking machines, it is advisable to exclude preliminary cross-cutting of gum, which significantly reduces the yield of short fibers;
II - chemical treatment of cellulose fibers. It is carried out in batch apparatuses with a liquid module 10-20 as follows:
- processing of fibers in an alkaline environment at a temperature of 18-25 ^o With by 90 minutes of keeping them in a solution containing, g / l:
Sodium hypochlorite (by active chlorine) - 2.3-3.5
A derivative of phosphonic or carboxylic acids with a number of phosphonic groups of at least two - 0.1-0.2
- washing with cold water;
- bleaching by oxidative cooking at a temperature of 96-98 ^o C for 110-120 minutes with a silicate-alkaline module (SiO ₂ / Na ₂ O) of at least 0.5 with a temperature rise to 96-98 ^o C for 60 minutes with a solution containing g / l:
Hydrogen peroxide (in terms of active oxygen) - 1.7-1.9
Silicate or sodium metasilicate (in terms of SiO ₂ ) - 2.3-3.5
A derivative of phosphonic or carboxylic acids with a number of phosphonic groups of at least 2 - 0.1-5.0
Magnesium sulfate or chloride - 0.1-0.5
Wetting agent - 0.2-0.5
Caustic and / or soda ash to a total alkalinity of 3.0-7.5
- washing with hot (80-90 ^o C) and cold water;
- acidification with a solution of mineral acid concentration of 1.0-1.5 g / l;
- washing with cold water;
- spin to a moisture content of 120-130%;
III - cellulosic fiber dispersion. It is carried out for each type of fiber on equipment traditionally used for this fiber, for example, short flax fiber is processed on lines (Laroche, Kardateks, etc.), providing loosening on the fiber cultivator, scratching on the carding machine.

 Analysis of the quality of the resulting cotton wool was carried out in accordance with GOST 5556-81.

 The compositions of the technological solutions and quality indicators of cotton wool obtained under different modes of chemical treatment of cellulose fibers are given in table. 1 and 2. Examples 12, 13 were obtained using tow, examples 14, 15 — ruminants, examples 16, 17 — cotton, and the rest — short flax fiber.

Claims (3)

1. A method of manufacturing cotton wool from cellulose fibers, including pre-machining them, chemical treatment by treating the fibers in an alkaline medium, washing and bleaching, acidification, washing and subsequent saponification, characterized in that the processing of fibers in an alkaline medium is carried out in the presence of sodium hypochlorite with a temperature of 18-25 ^o C, bleaching is carried out by oxidative cooking with a silicate-alkaline module of the solution of at least 0.5, with a total alkalinity of the solution of 3.0-7.5 g / l, washing during chemical processing t directly after processing the fibers in an alkaline medium and after bleaching, and when processing fibers in an alkaline medium and / or bleaching, a complexing compound is used - a derivative of carboxylic and / or phosphonic acid with at least 2 phosphonic groups.  2. The method according to claim 1, characterized in that the concentration of sodium hypochlorite is equal to 2.3-3.5 g / L.  3. The method according to claim 1, characterized in that the complexing compound is used at a concentration of 0.1-5.0 g / L.

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