BG112429A - A method for the manufacturing of antibacterial viscosal artificial silk and a product obtained by this method - Google Patents

Abstract

The antibacterial viscose artificial silk according to the invention is used for the manufacturing of any textile products, including those for medical purposes, as well as it provides longer bacterial and fungal protection due to the uniform distribution of the antibacterial additive throughout the volume of the fiber. According to the invention, just before the fiber-forming, the viscose is mixed with an antibacterial additive, it is homogenized and fiber-formed in the classic way: viscose solution with well-defined required parameters is fed under pressure to the fiber-forming nozzles of the fiber-forming machine, from which the effluent cellulose solution sprays fall into a precipitating bath, where as a result of ongoing chemical reactions they turn into filaments, which are subsequently subjected to further treatment. According to the invention, in the manufacturing of coloured antibacterial silk, to the pre-prepared pigment suspension of one or more pigments is added a fixed dose of antibacterial additive, the resulting mixture is homogenized and filtered, after which are performed the classical stages of fiber-forming and post-processing.

Description

Description

FIELD OF APPLICATION

The present invention relates to a method for the production of antibacterial viscose rayon and a product obtained by this method. BACKGROUND OF THE INVENTION

The classical technology for the production of viscose silk has not undergone much development, despite the considerable period that has elapsed since its creation, as the process itself is very conservative and is strongly influenced by various external and other factors. In general, this classic process of fiberization, performed on different types of fiberization machines, consists of the following:

First, the cellulose is subjected to so-called mercerization. which is the treatment of the starting cellulose with concentrated sodium hydroxide solution (NaOH) to give alkali and cellulose, which is then subjected to oxidative degradation, i.e., pre-ripening. thereby reducing the degree of polymerization. This is followed by lowering the temperature and dosing the amount of alkali cellulose to produce one batch of viscose. The next step is sulfidation, in which the alkali cellulose after treatment with carbon disulfide is transformed into cellulose xanthate, the most important property of which is that it is soluble in dilute sodium hydroxide solution. The cellulose solution from one batch is mixed and homogenized with that from the previous and next batches and deaerated, then filtered to remove contaminants. The viscous solution with precisely defined required parameters is then supplied under pressure for damping to the corresponding number of damping machines. The coating itself is performed by passing the cellulose solution through a dosing pump to a coating nozzle, from where the flowing streams of cellulose solution fall into a settling bath, where as a result of the ongoing chemical reactions they turn into fibers.

A refining step follows, in which the fresh-fiber viscose silk is treated with various solutions to remove residues from the precipitating bath, sodium sulphate and elemental sulfur resulting from the chemical reactions during the coating.

The resulting semi-finished product is dried, conditioned, rewound and sorted for subsequent grading and packaging as a finished product.

In the production of colored viscose silk, a pre-prepared pigment suspension of one or more pigments is added to the viscous solution prepared for coating. The required amount of the suspension is metered in and mixed with the viscose, this mixture being homogenized, whereby the pigment particles are evenly distributed throughout the volume of this solution. For the colored and homogenized cellulose solution, the classic stages of coating, refining and processing of the obtained semi-finished product are further performed - drying, conditioning, rewinding and sorting for subsequent grading and packaging as finished products.

Due to specific needs in textiles, fabrics with new consumer qualities are required, such as antibacterial properties with some level of bacterial or fungal protection. They are achieved by using an antibacterial additive, which is usually a solution or suspension of the antibacterial substance or substances in water in the presence of certain amounts of equalizer dispersants. wetting agents, softeners and others.

The following types of treatments are known in practice for obtaining antibacterial or fungal protection:

Immersion application - usually done on Foulard by water bath. The bath in these cases must be perfectly prepared just before use and in strict compliance with the mandatory requirement for continuous stirring in order to maintain a constant level of dispersion of the dispersed system if the antibacterial additive is in the form of a dispersion. Typically, a concentration of the additive of 0.14 to 0.70% of the weight of the fabric to be treated is used, and the treatment can be performed by introducing other finishing preparations in addition to the antibacterial additive to the composition of the bath. In such cases, however, prior testing of the compatibility of the antibacterial and other types of additives is required. The fabric with the antibacterial additive applied on it is immediately dried and thus the additive remains attached and to some extent fixed on its surface. ie it hardly penetrates the cross section of the different types of fibers used for the production of the fabric. How long the antibacterial action of the additive will last can be determined after performing several washes and examining after each of them whether and by how much the antibacterial protection of the additive remains after washing.

Extraction application - also applies to fabrics and especially to those made only of synthetic fibers. When using this method, work with a bath in a ratio of 10: 1 or less, at pH 4 - 8 and extraction time of at least 30 minutes and a temperature of at least 80 ° C. The use of lower temperatures can significantly reduce the efficiency of extraction. And with this method, the application is only on the entire surface of the woven or woven fabric. The additional use of equalizers can contribute to the even distribution of the antibacterial additive over the entire treated surface.

The main disadvantages of these methods of applying antibacterial additives are. that the duration of action of the additive depends only on the stability of its attachment to the treated surface and that uniformity in the manifestation of the bacterial protection cannot be guaranteed.

In addition, the antibacterial additive is partially absorbed, ie. not a small part of it remains in the bathroom after treatment, after which it is discharged into industrial wastewater. Therefore, the use of these methods has higher costs for industrial wastewater treatment, as well as environmental problems.

A method for producing antibacterial silk with antifungal and antiseptic properties and light resistance, described in JPH09310235 (A), is also known. According to the method from 5 to 10% a composition of inorganic compounds with particle sizes smaller than 5 microns is mixed with the viscose in a mixer or in the tank before deaeration at the stage of homogenization of the individual batches of viscose or in the viscose container before deaeration. . The resulting mixture after all subsequent steps such as filtration, for example, is fed to the spinning shop. The composition of inorganic compounds is 20 - 80%. to which are added from 20 - 80% silicon and from 10 - 40% zinc oxide after a process of agglomeration.

The disadvantage of this method is the complexity of the other processes of preparation of viscose for irrigation such as filtration and maturation, as well as the process of irradiation. due to the high concentration of inorganic particles in the composition of the viscose, introduced at a very early stage of mixing the viscous solution with the antibacterial composition.

In addition, the early introduction of the antibacterial ingredient requires separate streams for the movement of the untreated and mixed with the antibacterial composition viscose to the damping machines, i.e. separate communications are required if both types of silk are produced simultaneously.

A method for producing fibers with antibacterial properties is also described in patent application JPH17173711 (A). These fibers are obtained by surface treatment of viscose silk with an anionic high molecular weight substance and a quaternary ammonium salt of saturated or unsaturated fatty acids. The fibers.

obtained by this method have the disadvantages due to the surface treatment of already produced silk, mentioned above.

A method for the production of fibers with antiseptic properties is also described in patent application CN1779004 (A). The antiseptic additive used is silver, which is mixed with an acid ester of cellulose. The amount of silver is from 0.5 to 5.0% by weight of the cellulose. However, this method is unacceptable for the production of viscose fibers or silk, as the silver from the additive reacts with the hydrogen sulfide released during the coating of the viscose to silver sulphide, which gives the product a gray color.

It is also an object of the invention to provide a method for the production of white or colored viscose silk with the above-mentioned antibacterial and antifungal properties.

The development of this method is based on the well-known classical process of viscose or silk fiber coating, innovatively improved with the introduction of additional stages. to obtain a fiber in which the antibacterial additive is evenly distributed throughout the volume and cross section of the fiber (silk). In this way, significantly longer bacterial and fungal protection is achieved, without contaminating the wastewater.

SUMMARY OF THE INVENTION

According to the invention, there is provided a method for the direct production of viscose artificial silk with antibacterial properties, in which the following steps are performed:

First, the starting cellulose is treated with a concentrated sodium hydroxide solution (NaOH) to give alkaliscellulose, which is then subjected to oxidative degradation, i.e., pre-ripening, whereby the degree of polymerization is reduced. This is followed by lowering the temperature and dosing the amount of alkali cellulose to produce one batch of viscose. The next step is sulfidation, in which the alkali cellulose after treatment with carbon disulfide is transformed into cellulose xanthate, which is soluble in dilute sodium hydroxide solution. The cellulose solution from one batch is mixed and homogenized with that from the previous and next batches and vented. then filtered to remove contaminants.

According to the invention, immediately before coating, the viscose is mixed with an antibacterial additive, homogenized and dried according to the classical scheme, namely the viscous solution with precisely defined required parameters is fed under pressure to the coating nozzles, from where the flowing streams of cellulose solution fall into the bath. , where as a result of ongoing chemical reactions they turn into fibers.

This is followed by a refining step in which the freshly fibrous viscose silk is treated with various solutions to remove residues from the settling bath, sodium sulphate and elemental sulfur resulting from the chemical reactions of damping, drying, conditioning, rewinding and sorting. of the finished product.

According to the invention, in the production of colored antibacterial silk, the determined dose of antibacterial additive is added to the pre-prepared pigment suspension of one or more pigments, the resulting mixture is homogenized and filtered, after which the classic steps are performed: pressure supply of viscous solution with precisely defined requirements parameters for damping to a damping machine, and when it is applied for damping the cellulose solution is mixed in a certain ratio with the suspension. Then it passes through a dosing pump to a damping nozzle, from where the flowing streams of cellulose solution fall into a settling bath. reactions turned into threads.

A refining step follows, in which the freshly coated viscose silk is treated with various solutions to remove residues from the precipitating bath, sodium sulphate and elemental sulfur resulting from the chemical reactions during the encapsulation.

The resulting semi-finished product is dried, conditioned, rewound and sorted for subsequent grading and packaging as a finished product.

According to the invention, the amount of the antibacterial additive is from 0.01 to 5% relative to the amount of cellulose in the viscous solution, and in the case of using the additive K.W 48 this concentration is from 0.5 to 3.5%.

In addition, according to the invention, the preparation of the antibacterial suspension and its storage take place at temperatures from + 20 ° C to - 4 ° C.

In addition, according to the invention, the antibacterial suspension is filtered to remove all particles larger than 5 microns.

In carrying out the invention, a viscous silk with antibacterial properties is obtained, which can be used for the production of any products, including those for medical purposes, as the antibacterial additive is evenly distributed throughout the volume and cross section of the fiber (silk). which implies significantly longer action and, accordingly, longer bacterial and fungal protection.

In addition, the antibacterial additive is 100% utilized and there are no waste and polluting wastewater, which is extremely important from an environmental point of view.

Among all other advantages, the change in the place of use of the antibacterial additive allows for the production of colored antibacterial viscose silk with the preparation of combined recipes for the production of colors, with the antibacterial additive becoming an integral part of the recipe. The total suspension of pigments and antibacterial additive is transported to a homogenization vessel in the cellulose solution according to the innovative scheme, after which it is sent directly for coating.

BRIEF DESCRIPTION OF THE ATTACHED FIGURES

Figure 1 is a block diagram illustrating the sequence of processes in the production of viscose rayon.

Figure 2 shows a block diagram of a unit (10-1) for dyeing viscose in bulk without and using an antibacterial additive.

Figure 3 shows a schematic structural diagram of a damping machine.

Figure 4 in Table shows the recipe for the preparation of the suspension with an antibacterial additive introduced into the cellulose solution in the homogenizer.

Figures 5a and 56 show the results of antibacterial tests on samples of antibacterial silk produced by the method according to the invention. EXAMPLE IMPLEMENTATION OF THE METHOD FOR THE PRODUCTION OF ANTIBACTERIAL VISCOSE ARTIFICIAL SILK

With reference to Figures 1, 2 and 3, an exemplary embodiment of the method according to the invention is shown.

First, the starting cellulose is fed to block 1 for mercerization - treatment with concentrated sodium hydroxide solution (NaOH), to obtain alkalicellulose. which is then subjected to oxidative degradation in block 2, ie pre-ripening. thereby reducing the degree of polymerization. In block 3, a reduction of the temperature is performed, and in block 4 - dosing of an amount of alkali cellulose for the production of one batch of viscose. In block 5, the sulfidation-treatment of alkali cellulose with carbon disulfide is carried out to obtain cellulose xanthate. In blocks 6 and 7, the cellulose solution from one batch is mixed and homogenized with that from the previous and next batches and vented, then filtered in block 8 to remove contaminants. Then, if no colored silk is produced, the viscous solution with precisely defined required parameters is supplied under pressure to the corresponding number of drawing machines 10 in a common tubular collector 36. which is continuously filled with cellulose solution under imposition to prevent the formation of a gas phase . From the common collector 36 through the individual collector 37 for each damping machine, the viscous solution enters the tubular collector 38, through which the required amount of cellulose solution is provided to the damping nozzle at each working point of the damping machine 10 through a corresponding dosing pump 22 (Fig. 3). . Leaving the nozzle 26 (Fig. 3), the jets of cellulose solution fall into the settling bath 11. where as a result of the ongoing chemical reactions they turn into threads. Leaving the bath, the freshly fiber pulp is moved and placed in a receiving centrifuge 29 (Fig. 3). When it is filled to a certain volume, the thread between the receiving mechanisms 27 and 28 (Fig. 3) is interrupted and wound only on the receiving mechanism 27. During this time the centrifuge 29 is stopped, the yarn body formed in it is removed, after which the centrifuge is switched on again. When it enters the operating mode, the thread from the receiving mechanism 27 is again transferred to the receiving mechanism 28 and from there enters the centrifuge 29. which starts the production of the next yarn body.

A refining step follows, in which in block 12 the freshly fibrous viscose silk is treated with various solutions prepared in block 13 to remove residues from the precipitating bath, sodium sulphate and elemental sulfur resulting from the chemical reactions in the coating.

The resulting semi-finished product is centrifuged, dried, conditioned, rewound and sorted for subsequent grading and packaging as finished products - blocks 14, 15. 16, 17, 18, and after grading - block 19. is stored.

In the production of colored silk, the fiberizing machine 10 is supplemented with a unit 10-1 (Fig. 2) for individual or group dyeing in the mass. To carry out such production, a pre-prepared pigment suspension is added to the viscous solution before coating, which is stored in a container 30 for the duration of the production cycle (Fig. 2). With the pump 31 the required amount of the suspension is metered into the viscose and the mixture enters the homogenizer 32 (Fig. 2). There, the cellulose solution is mixed with the suspension, and in doing so, the pigment particles must be evenly distributed throughout the volume of this solution. The cellulose solution already colored after homogenization enters the viscose line 38 (Fig. 2) of the spinning machine, after which the solution moves to the damping nozzle in the manner already described.

In the shown embodiment of the invention for the production of antibacterial viscose silk according to the recipe (Fig. 4), the suspension of the antibacterial additive is prepared, i. 1.0% related to the amount of cellulose that will be fibrous in 24 hours. The calculated amount of additive is weighed and quantitatively transferred to the container for preparation of the suspension, where the required amount of water and other components of the recipe have already been pre-weighed. The prepared suspension is transported to the vessel 30 of the individual mass dyeing plant (Fig. 2), after which the supply of the suspension to the homogenizer 32 is adjusted by the dosing suspension pump 31. This adjustment is performed when the collector viscose line 38 is filled with cellulose solution. and airless. This is followed by wrapping as described.

After the viscose is mixed with the suspension, whatever it is, as a result of the dilution, its parameters change:

Before dosing After dosing

of the suspension the suspension -viscosity sec. 39.0 30.0 -maturity Jr.MNdS! 19.25 17.40 -temperature ° C 17.0 19.0

The coating of the complex with a viscous solution of antibacterial additive is carried out with the precipitation bath used for coating of the same solution without such additive or of the same solution, dyed in mass.

After the damping, the freshly dyed antibacterial silk undergoes the treatments to which the silk drenched on all spinning machines is subjected, ie these treatments are performed in a general technological order and flow. These treatments include rinsing with softened water, neutralization with sodium bicarbonate, desulfurization and again rinsing with softened water.

Drying and rewinding of coils of normal weight and volume is performed in the same way and parameters as all other yarn bodies produced in the classical way. The only difference is that the rewinding of the antibacterial silk is done on separate rewinding machines so that it does not mix with the rest and is graded immediately, after which each of the coils is packed in a sterile package.

The grading is performed according to the same scheme as for the traditionally produced assortments of viscose silk. If necessary, samples are also taken in sterile packages to determine the degree of bacterial protection against bacteria and fungi.

Figures 5a and 56 show the results of antibacterial tests on samples of antibacterial silk produced by the method according to the invention.

The introduction of any kind of additives to the viscous solution changes its parameters and especially the rate of maturation. Therefore, the introduction of the additive in viscose immediately before its coating, which is the innovative solution of the proposed method, is one of its significant advantages over all known so far, because changes in the composition of the cellulose solution occur minutes before its coating, which is guarantee for its trouble-free humidification without the need to change the other parameters of the fiberization process.

Claims (7)

Patent claims 1. A method of producing antibacterial viscose rayon, comprising the steps of: treating the crude cellulose with a concentrated sodium hydroxide solution to give alkaliscellulose, which is then subjected to oxidative degradation to reduce the degree of polymerization; lowering the temperature and dosing an amount of alkali cellulose to produce one batch of viscose; treatment of the alkaline cellulose with carbon disulphide until its transformation into cellulose xanthate, which is soluble in dilute sodium hydroxide solution, filtration to remove contaminants and subsequent coating. including pressure supply through a dosing pump to a damping nozzle, from where the flowing streams of cellulose solution fall into a settling bath, where as a result of ongoing chemical reactions are converted into fibers, treatment with various solutions to remove residues from settling bath, sodium sulfate and elemental sulfur resulting from chemical reactions in the coating: drying, conditioning, rewinding and sorting, characterized in that immediately before the coating the cellulose solution is mixed with the antibacterial additive, homogenized, then the coating and the subsequent mentioned steps. A method for producing an antibacterial colored viscose rayon, comprising the steps of: treating the crude cellulose with a concentrated sodium hydroxide solution to obtain alkalicellulose, which is then subjected to oxidative degradation to reduce the degree of polymerization; lowering the temperature and dosing an amount of alkali cellulose to produce one batch of viscose; treating the alkali cellulose with carbon disulphide until it is transformed into cellulose xanthate, which is soluble in dilute sodium hydroxide solution, filtration to remove contaminants and subsequent embossing, including pressurizing through a dosing pump to a emulsion nozzle from which the effluent flows. a settling bath, where, as a result of the ongoing chemical reactions, they are converted into fibers, treated with various solutions to remove residues of the settling bath, sodium sulphate and elemental sulfur resulting from the chemical reactions in the coating; drying. conditioning, rewinding and sorting, characterized in that immediately before coating the antibacterial additive is mixed and homogenized with different colored dispersed pigments according to a previously executed recipe, after which the already colored and treated with antibacterial additive viscose again goes for coating. perform the mentioned stages. Method according to claims 1 or 2, characterized in that the amount of the antibacterial additive is from 0.01 to 5% relative to the amount of cellulose in the viscous solution. Method according to claim 3, characterized in that when using KW 48 as an antibacterial additive, its amount is from 0.5 to 3.5% relative to the amount of cellulose in the viscous solution. Method according to claim 3, characterized in that the preparation of the antibacterial suspension and its storage take place at temperatures from + 20 ° C to -4 ° C. Method according to claim 3, characterized in that the antibacterial suspension is filtered to remove all particles larger than 5 microns. A product obtained by the method according to any one of the preceding claims.