RU2525545C2 - Method of production of antimicrobial argentiferous cellulosic material - Google Patents

Abstract

FIELD: textiles, paper.

SUBSTANCE: invention can be used in the textile industry for production of antimicrobial argentiferous cellulosic materials. The method of production of antimicrobial argentiferous cellulosic material comprises processing of the cellulose matrix by the aqueous dispersion of the silver particles for 10-60 sec, obtained by mixing an alkali extract of bast fibres with an aqueous solution of silver nitrate and keeping this mixture at a temperature of 50-95°C for 10-90 min.

EFFECT: invention enables to reduce loss of the active components, to reduce the time and energy consumption during production of antimicrobial materials and also to improve the quality of the processed nonwoven material and environmental safety.

4 cl, 2 tbl, 8 ex

Description

Introduction

The invention relates to the textile industry and nanotechnology and can be used to obtain modified biologically active cellulosic materials for widespread use in various fields of medicine, cosmetology and in everyday life, for example, in the manufacture of antimicrobial non-woven fabrics for wound healing products, surgical sheets, gowns, cosmetic masks , napkins for applications, hygiene items.

State of the art

The problem of constantly increasing consumer requirements for the quality of products for medicine, hygiene, cosmetology is solved using natural cellulose fibers, because it is the natural origin of the fibers, their ecological purity that play an important role in achieving a person's sensations of safety, tactile, psychological and aesthetic comfort. In addition, thanks to a complex of high hygienic, operational, and in the case of flax fibers and unique biomedical natural properties, flax and cotton fibers and materials based on them can be used in the manufacture of high-tech products for medicine, hygiene, and cosmetology.

At the same time, the antimicrobial properties of cellulose fibers can be improved by introducing into their structure metal particles that are vital for humans, such as silver.

Interest in the development and use of silver-containing drugs for medical purposes throughout the world is constantly growing. This is due to the extremely valuable complex of therapeutic properties inherent in silver preparations:

- a wide antibacterial spectrum in relation to pathogenic flora, including resistant to antibiotics;

- the complexity of developing protective mechanisms against the action of silver in pathogenic microorganisms;

- the presence of virucidal and fungicidal activity, which is especially valuable in the case of associations of bacterial and viral or fungal infections;

- well-defined wound healing effect;

- in small concentrations safe for human cells;

- relatively low cost of drugs.

The unique antimicrobial and antiviral properties of silver compounds have been comprehensively studied. The bactericidal properties of metallic silver are associated with its slow oxidation and release of Ag ⁺ ions into the environment. In this regard, the use of nanosilver preparations as a special class of biocidal agents seems to be promising. Modern technologies make it possible to prepare silver preparations in a wide variety of dosage forms, namely: in the form of a solution, gel, cream, aerosol, powder, dressings. Such a variety of dosage forms of silver preparations makes them universal. Depending on the nature and stage of the disease, one or another dosage form is most effective.

Currently, it is of considerable interest to obtain antibacterial fibrous textile materials, including nanosized particles of silver or its sparingly soluble compounds. Thus, there are known methods of obtaining (patents JP 62004472, publ. 12.12.1992, and US Patent 5888526, publ. 30.03 1999) a fibrous material containing antibacterial and antifungal agents, including heterocyclic organic compounds that contain copper, zinc ions and silver. The disadvantages of these methods are the complexity of the process and the high cost of the materials used.

A known method of producing tissue with a wide spectrum of antibacterial action (Chinese Patent No. 921092881). The method consists in impregnating the material with an ammonia solution of silver nitrate, followed by its restoration with glucose and heat treatment of the impregnated fabric when ironed with an iron or a rotating drum. The disadvantage of this method is the use of toxic ammonia.

A known method for producing antimicrobial silver-containing materials (RU 2402655, publ. 10.27.2010), in particular based on the natural polymer fibroin. The method consists in impregnating a natural polymer with an aqueous solution of silver nitrate at a concentration of 0.025-1.0 wt.% For 20-60 minutes Sodium borohydride is additionally introduced into the solution at a ratio of silver nitrate: sodium borohydride 1: 1-1: 10. The material is impregnated with a bath module of 1: 10-1: 25. The material is used in the form of fiber, woven, non-woven or knitted material.

The disadvantage of this method is the low efficiency of the process, due to the following factors:

- the high cost of natural silk fibroin;

- the use of an expensive reducing agent (sodium borohydride);

- a high modulus of the impregnation bath and, therefore, a significant overrun of the drug.

A known method for producing an antibacterial fibrous material, comprising reducing silver from an aqueous solution of silver nitrate with reducing agents and applying reduced silver to the material (US Pat. No. 6979491, class 428-361 of 12/27/2005). As reducing agents, glucose, ascorbic acid (vitamin C), hydrazine or hydrazine hydrate were used. After the deposition of silver particles on the material, dehydration and drying were carried out at 120–160 ° С for 40–60 min. The resulting product has an antibacterial effect against bacteria, fungi. However, the method does not provide sufficient bonding strength of nanosized particles of metallic silver with a tissue carrier, which does not allow reuse of textile fibrous material. In addition, the material is painted, depending on the concentration of silver, in gray-black tones, which reduces its consumer appeal. Drying of the material at a temperature of 120-160 ° C for 40-60 minutes can lead to its destruction.

A known method of producing an antibacterial textile fibrous material based on cotton, linen, silk, wool, including the restoration of silver from an aqueous solution of silver nitrate by reducing agents and applying reduced silver to a fibrous material (RU 2350356, publ. 03/27/2009), and recovery of nitrate silver is carried out with a reducing agent, mounted on a fibrous material, for which, first, the fibrous material is processed in a water solution of tannins based on that heated to 70-90 ° С nnine, which acts as a reducing agent with a concentration of 0.2-2.0 wt.%, and after cooling, the aqueous phase is separated off, dried and then tannin is fixed on the fibrous material by impregnation at 20-30 ° C in a solution of potassium antimonyl tartrate with a concentration of 0, 5-1.5 wt.%, The aqueous phase is separated, washed with water, after which the wet fibrous material is placed in an aqueous solution of silver nitrate with a concentration of 0.1-3.0 wt.% Heated to 50-100 ° C, and the aqueous phase is separated and drying the resulting fibrous material coated with silver.

The disadvantage of this method is that it is quite complex, multi-stage and expensive.

Closest to the claimed invention is a method for producing antimicrobial silver-containing cellulosic material, in particular flax fibers (RU 2256675, publ. 10.06.2003). The method is implemented as follows:

- prepare a solution containing 0.25-2.0 wt.% silver nitrate, 0.5-15 vol.% ammonia or 20-50 wt.% glycerol (or a mixture of ammonia and glycerin;

- the cellulosic material at room temperature is impregnated with the prepared solution. The ratio of cellulosic material: an aqueous solution is 1 g per 15-30 ml;

- heat the reaction mixture at 85-150 ° C for 1-4 hours

Materials with a low (0.2-1.0%) silver content are used as bactericidal dressings, medical clothes, bedding, hygiene items, and materials with a silver content of 2-17.5% as filters for disinfecting drinking water .

However, the method has disadvantages.

Low profitability due to the following factors:

- only 2-5% of the mass of all silver used to prepare the solution remains on the material, the rest of the salt goes to drainage water;

- the need for a long (up to 4 hours) processing of textile material at high temperature, which leads to a large consumption of electricity;

- weak fixation of silver particles on the surface of the material and its removal during washing;

- significant overrun of chemicals due to the process at high liquid modules (m = 15-30), i.e. the excess of the mass of the solution over the mass of the material is 15-30 times, which is much more than in traditional periodic methods of processing fibers and fabrics (m = 5-10).

Low quality indicators due to the following factors:

- the proposed conditions for liquid processing (keeping the material in the reaction mixture at a temperature of 100 ° C for 1.5 hours) of the non-woven fabric will inevitably lead to its deformation and even destruction of the structure, which makes the practical use of the finished material impossible;

- to increase the silver content, ammonia and glycerin are added to the treatment solution in order to loosen the fiber surface, as a result of which, when wet, most of the silver is washed off and antimicrobial activity is lost until complete loss after 2 washes.

Non-environmental due to the ingress of glycerol and its derivatives into wastewater resulting from oxidation and reaction with silver ions.

SUMMARY OF THE INVENTION

The objective of the invention is to search for a method for producing an antimicrobial silver-containing cellulosic material by applying ultrafine silver particles to the cellulose matrix, which would improve production efficiency, material quality and environmental friendliness of the method.

The problem is solved by the method of obtaining antimicrobial silver-containing cellulosic material, which consists in processing the cellulose matrix with an aqueous dispersion of silver particles at a concentration of 0.006-0.18 wt.% For 10-60 seconds, obtained by mixing an alkaline extract of bast fibers with an aqueous solution of silver nitrate and keeping this mixture at a temperature of 50-95 ° C for 10-90 minutes.

Wherein:

- the concentration of alkaline extract of bast fibers in the dispersion is 40-80%;

- treatment of cellulosic material with an aqueous dispersion of silver particles is carried out by impregnation or aerosol application;

- the aqueous dispersion may contain an antiseptic or disinfectant that does not reduce the aggregative stability of silver particles, for example dioxidine, miramistin, preparations based on polyhexamethylguanidine hydrochloride or quaternary ammonium compounds.

The invention allows to obtain the following advantages:

1. Increase efficiency by:

- the absence of unproductive losses of active components when applied to textile material to achieve a high antimicrobial effect, since there is no need to use high concentrations of silver nitrate;

- reducing the duration of the method for producing antimicrobial materials and reducing energy costs due to the lack of high temperature heating;

- the formation of a metal phase in the presence of high molecular weight compounds extracted from bast fibers (polysaccharides, lignin derivatives, flavonoids) capable of reducing and stabilizing silver nanoparticles and ensuring the aggregative stability of the resulting aqueous dispersion;

- the possibility of reuse of the aqueous dispersion remaining after the impregnation of the material;

- the complete consumption of the aqueous dispersion during its aerosol deposition on cellulosic materials;

- the absence of a reducing agent, since without it a complete transition of silver cations to a zero-valence state is ensured;

2. High quality material processing, including non-woven fabric, as allows aerosol application of the dispersion on a non-woven cellulosic fabric, in which its physical, mechanical, operational and aesthetic properties are preserved;

3. Improving environmental safety by:

- lack of wastewater during aerosol dispersion application;

- stabilization of ultrafine silver particles by natural polymers extracted from flax fibers and other bast fibers without the use of chemicals.

In addition, the invention also has the following advantages:

- An accessible raw material base, since flax and other bast fibers are annually reproducible;

- allows you to get antimicrobial materials on the equipment available at textile enterprises with an economical continuous processing method: impregnation-spin-drying;

- the fiber remaining after receiving the extract from it does not go to waste, but can be used for further processing;

- easily hydrolyzable polysaccharides, lignin derivatives and flavonoids extracted from bast fibers, for example flax, solutions of alkaline agents, have their own biological activity and have a therapeutic effect, therefore, remaining on cellulosic material contribute to the acceleration of wound healing, elimination of toxic, ballast substances and metabolites from the body.

The antimicrobial silver-containing cellulosic materials obtained by the proposed method, according to the functional properties, meet the requirements for materials for medical, hygienic and cosmetic products, and provide activity against the gram-positive test culture Staphylococcus aureus, gram-negative culture Escherichia coli M-17 and yeast-like fungal culture of Candida albicans.

Information confirming the possibility of carrying out the invention

As the raw material, you can use boiled or bleached flax and cotton fibers, fabrics based on them or non-woven fabrics from their mixture with cellulose hydrated fiber.

To implement the method using the following chemicals:

Silver nitrate AgNO ₃ (GOST 1277-75).

Polyhexamethylene guanidine hydrochloride (TU 9392-010-41547288-2000) - refers to the high molecular weight derivatives of guanidine.

Quaternary ammonium compounds, for example Sanitized DET 89-39 (Registration number 77.99.1.2. U.4948.6.10 dated 06/30/2010).

Dioxidine (Registration number P N000806 / 02 (2002-12-09-0000-00-00) - refers to quinoxaline derivatives.

Miramistin - (Registration number 00192601 dated 01/13/2008).

Alkaline bast fiber extract - an aqueous solution containing a complex of compounds (easily hydrolyzable polysaccharides, lignin derivatives, flavonoids, etc.) extracted from bast fibers. It is obtained by treating the fibers with solutions of alkaline agents, for example, hydroxide or sodium carbonate, at a temperature of 20-100 ° C for 20-180 minutes.

The method is implemented by sequentially carrying out the following operations:

1. Processing at room temperature of the textile material with an aqueous dispersion containing silver particles of 0.006-0.18 wt.%.

It can be carried out by impregnation or aerosol application methods on equipment traditionally used for a particular type of material, for example:

- linen or cotton fibers in bulk can be treated with the economical method of aerosol spraying of 10-100% aqueous dispersion on the line of dosed deposition of reagents (LDN), or periodically in AKD apparatus with a low liquid module 4-5;

- it is advisable to treat the fabric with a straightened web in continuous ways, for example, on the SHMS lines (“Textima”, “Wakayama”, “Elitex”) or LZO;

- non-woven fabrics in order to avoid deformation of their structure can be processed by aerosol application of 30-100% aqueous dispersion.

In this case, an aqueous dispersion is obtained by mixing an alkaline extract of bast fibers with a solution of silver salt and keeping this mixture at a temperature of 50-95 ° C for 10-90 minutes. The concentration of silver nitrate is selected based on the desired concentration of silver particles in the dispersion. The concentration of alkaline extract of bast fibers in the dispersion is 40-80%. To expand the scope of application of silver-containing cellulosic materials (sanitary-hygienic or technical products, for example, insoles in shoes, soundproofing coatings, etc.), 0.1-15 g / l of antiseptic or disinfectant can be added to the dispersion, for example, dioxidine, miramistin, preparations based on polyhexamethyl guanidine hydrochloride, or quaternary ammonium compounds, etc.

Example 1

To obtain an aqueous dispersion of silver particles containing 0.09 wt.% Silver particles, 50 ml of flax fiber extract is poured into a container, 50 ml of a 0.3% silver nitrate solution is added, the reaction mixture is heated to a temperature of 95 ° C and kept for 10 minutes, cool.

10 g of bleached linen fabric with a surface density of 180 g / m ^{2 is} impregnated at room temperature with the dispersion obtained for 30 seconds, squeezed to a residual solution on the material of 100% and dried. The resulting material acquires a golden brown color.

The remaining solution can be reused to process the next sample.

Example 2

To obtain an aqueous dispersion of silver particles containing 0.006 wt.% Silver particles, 50 ml of flax fiber extract is poured into a container, 50 ml of a 0.02% silver nitrate solution is added, the reaction mixture is heated to a temperature of 70 ° C and held for 20 minutes, cool, add a preparation based on polyhexamethylguanidine hydrochloride in an amount of 1.0 wt.%.

10 g of bleached flax-containing fabric (cotton base; duck weft) with a surface density of 150 g / m ^{2 is} impregnated at room temperature with the dispersion obtained for 10 seconds, squeezed to a residual solution on the material of 100% and dried. The resulting material acquires a light brown color.

The remaining solution can be reused to process the next sample.

Example 3

To obtain an aqueous dispersion of silver particles containing 0.12 wt.% Silver particles, 50 ml of flax fiber extract is poured into a container, 50 ml of a 0.4% silver nitrate solution is added, the reaction mixture is heated to a temperature of 50 ° C and kept for 60 minutes, cool.

For 100 g of bleached flax fiber, decomposed in a thin layer, 100 ml of the obtained aqueous dispersion of silver particles is applied by aerosol method (100% application), after which the fiber is dried. The resulting material acquires a golden brown color.

Example 4

To obtain an aqueous dispersion of silver particles containing 0.03 wt.% Silver particles, 50 ml of hemp fiber extract is poured into a container, 50 ml of a 0.1% silver nitrate solution is added, the reaction mixture is heated to a temperature of 60 ° C and kept for 60 min, cool, add the drug Sanitized DET 89-39 in an amount of 1.5 wt.%.

For 100 g of a non-woven fabric from a mixture of bleached linen and hydrated cellulose fibers (surface density 100 g / m ² ), 100 ml of the obtained aqueous dispersion of copper particles (100% application) is applied by aerosol, after which the material is dried. The resulting material acquires a light brown color.

Example 5

To obtain an aqueous dispersion of silver particles containing 0.03 wt.% Silver particles, 50 ml of flax fiber extract is poured into a container, 50 ml of a 0.1% silver nitrate solution is added, the reaction mixture is heated to a temperature of 50 ° C and kept for 90 minutes, cool, add dioxidine in a concentration of 0.1 wt.%.

On 300 g of bleached cotton fiber, decomposed in a thin layer, 100 ml of the obtained aqueous dispersion of copper particles (30% application) is applied by aerosol method, after which the fiber is dried. The resulting material becomes yellow-brown.

Example 6

To obtain an aqueous dispersion of silver particles containing 0.06 wt.% Silver particles, 50 ml of flax fiber extract is poured into a container, 50 ml of a 0.2% silver nitrate solution is added, the reaction mixture is heated to a temperature of 50 ° C and kept for 90 min, cool, add miramistin in a concentration of 0.5 wt.%.

10 g of bleached linen cloth with a surface density of 180 t / and soaked at room temperature in 100 ml of the obtained aqueous dispersion of copper particles for 60 seconds, squeezed to a residual solution of 100% on the material and dried. The resulting material acquires a light brown color.

The remaining solution can be reused to process the next sample.

Example 7

To obtain an aqueous dispersion of silver particles containing 0.18 wt.% Silver particles, 50 ml of flax fiber extract is poured into a container, 50 ml of a 0.6% silver nitrate solution is added, the reaction mixture is heated to a temperature of 80 ° C and kept for 20 minutes, cool.

20 g of bleached flax fiber is treated at room temperature in a batch apparatus with a liquid module 5 in 100 ml of the obtained aqueous dispersion of copper particles for 10 min, squeezed to a residual solution on the fiber of 100% and dried. The resulting material acquires an intensely brown color.

The remaining solution can be reused to process the next sample.

Example 8 (prototype)

To 0.5 g of bleached linen fabric is poured 10 ml of a 0.25 wt.% Aqueous solution of AgNO ₃ containing 1 wt.% A solution of ammonia. The reaction mixture is heated at 100 ° C until the browning stops - 1.5 hours. The material turns dark brown or dark gray. The material is washed with excess water and dried at a temperature of 35-40 ° C.

Diagnosis and testing of antimicrobial cellulosic fibrous materials containing silver particles was carried out by traditional methods at the Department of Microbiology, Ivanovo State Medical Academy (IGMA) using the following methods:

The antimicrobial activity of silver-containing cellulose fibers was evaluated on the basis of changes in the light transmission coefficients of solutions containing nutrient medium for microbial cultures, before and after the introduction of the studied samples. The analysis was carried out as follows - fiber samples were placed in test tubes with meat-peptone broth with the addition of suspensions of microbial test cultures (Escherichia coli M-17, Staphylococcus aureus, Candida albicans) in concentrations from 10 to 10 cells / ml. Suppression of the development of microbial cultures, accompanied by an increase in light transmission coefficients, is evidence of the antimicrobial activity of the tested copper-containing fibers. The conclusion about antimicrobial activity was made by the degree of increase in the transmittance after introducing the fiber into a solution containing a nutrient medium and microbial culture.

The activity of antimicrobial silver-containing tissue samples and non-woven materials was evaluated by the growth retardation zone of bacterial and fungal cultures under the influence of substances diffusing from the sample into an agarized nutrient medium. Test cultures of Escherichia coli M-17, Staphylococcus aureus, and Candida albicans grown on a nutrient medium were inoculated with the lawn method on nutrient media in Petri dishes and, after drying of the surface of the cup, the samples of the tested materials were applied to the medium surface using aseptic conditions, the size of which was tested 10 × 10 mm. The plates were incubated at 37 ° C.

The stability of the antimicrobial properties of reusable tissues was proved by the invariance of color and the presence of bacteriostatic properties after repeated washings.

The conditions of the method for producing antimicrobial silver-containing cellulosic material and the quality indicators of the processed cellulosic materials are shown in tables 1 and 2, respectively.

Antimicrobial materials for medicine, hygiene and cosmetology, possessing a wide spectrum of antimicrobial activity, at the same time must guarantee the absence of allergic effects in contact with the surface of the skin or with the wound surface. Therefore, for the manufacture of dressings, wound dressings, napkins, applicators and other means involving prolonged contact with human skin, silver-containing cellulosic materials must have antimicrobial activity that is minimally necessary for the conditions of a specific drug therapy (delay zones should be no more than 4 mm).

So, the material according to examples 1 and 3, characterized by a 4 mm delay zone, can be used for the production of medical and cosmetic products, and the materials according to examples 2, 6, 7 with 6-9 mm delay zones can be used to produce sanitary-hygienic products and technical purposes.

The presented results prove that the invention allows to obtain antimicrobial cellulosic materials that have high antimicrobial activity against gram-negative E. coli (3-6 mm), gram-positive St.saureus (5-8 mm) and Candida fungal cultures (8-10 mm) and comply with the requirements for cellulosic materials sent to the manufacture of high-quality products for various purposes.

Table 1. The conditions for the implementation of the method of obtaining No. Cellulosic material, type of dispersion treatment Conc. silver salts in solution, wt.% Temperature/
synthesis time, ° C / min Conc. silver particles on the material wt.% The presence of an antiseptic or des. facilities The concentration of antiseptic or des. means, wt.% one Linen, impregnated 0.15 95/10 0.09 - - 2 Linen, impregnated 0.01 70/20 0.006 drug based on polyhexameth
ilguanidine hydrochloride 1,0 3 Flax fiber, spray application 0.2 60/10 0.12 four Non-woven fabric, spray application 0.05 60/60 0,03 Sanitary DET 89-39 1,5 5 Cotton fiber, spray application 0.05 50/60 0,03 dioxidine 0.1 6 Linen cotton fabric, impregnation 0.1 50/60 0.06 miramistin 0.5 7 Flax fiber impregnation 0.3 80/20 0.18 - - 8 pro
that-
type of Linen, impregnated 0.25 100/90 3.0 - -

table 2 Qualitative indicators of processed cellulosic materials No. at
measure Type of material to be processed Fabrics, non-woven fabrics Fibers Zone of growth inhibition of culture, mm The effect of inhibitory effects on culture,% relative to control Candida albicans Escherichia coli M-17 Staphylococcus aureus Candida albicans Escherichia coli M-17 Staphylococcus aureus one 5 four four 2 8 6 6 3 86 72 74 four 8 3 5 5 90 81 88 6 8 6 7 7 92 88 90 8 pro
that-
type of 10 6 5

Claims (4)

1. The method of obtaining antimicrobial silver-containing cellulosic material, which consists in processing the cellulose matrix with an aqueous dispersion of silver particles at a concentration of 0.006-0.18 wt.% For 10-60 sec, obtained by mixing an alkaline extract of bast fibers with an aqueous solution of silver nitrate and aging this mixture at a temperature of 50-95 ° C for 10-90 minutes. 2. The method according to p. 1, characterized in that the concentration of alkaline extract of bast fibers in the dispersion is 40-80%. 3. The method according to p. 1, characterized in that the treatment of cellulosic material with an aqueous dispersion of silver particles is carried out by impregnation or aerosol application. 4. The method according to p. 1, characterized in that the aqueous dispersion of silver particles may contain an antiseptic or disinfectant that does not reduce the aggregative stability of silver particles, for example dioxidine, miramistin, preparations based on polyhexamethylguanidine hydrochloride or quaternary ammonium compounds.