BG67099B1 - 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

Field of technology

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 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:

The cellulose is first subjected to so-called mercerization, which is the treatment of the starting cellulose with a concentrated sodium hydroxide solution (NaOH) to give alkalicellulose, which is then subjected to oxidative degradation, i.e. pre-ripening, in which case reduces 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 to the corresponding number of exposure 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 freshly moistened 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 moistening.

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 in this way, the classical stages of wetting are further performed. refining and processing of the obtained semi-finished product - drying, conditioning, rewinding and sorting for subsequent grading and packaging as finished products.

Due to specific needs in textiles, fabrics with new consumer properties 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 equalizers, dispersants, wetting agents. softeners and others.

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

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. A concentration of the additive is usually used from 0.14 to 0.70% of the weight of the fabric to be treated, and the treatment can be performed by introducing into the composition of the bath in addition to the antibacterial additive and

Descriptions of issued patents for inventions № 07.2 / 31.07.2020 other finishing preparations. 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. 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 can not guarantee uniformity in the manifestation of bacterial protection.

In addition, the antibacterial additive is partially absorbed, they. 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 μ is mixed with the viscose in a mixer or 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 20 - 80% silicon and 10 - 40% zinc oxide after a process of agglomeration.

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

In addition, the early administration of the antibacterial ingredient requires separate streams for the movement of the untreated and mixed with the antibacterial composition viscose to the coating machines, ie. require separate communications 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 macromolecular 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 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 sulfide, 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 fiberization

Descriptions of issued patents for inventions № 07.2 / 31.07.2020 viscose fibers or silk 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.

Technical essence of the invention

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

The starting cellulose is first treated with a concentrated sodium hydroxide solution (NaOH) to give alkalicellulose, which is then subjected to oxidative degradation, i. pre-ripening, which reduces 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, 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 deaerated, then filtered to remove contaminants.

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

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

According to the invention, in the production of colored antibacterial silk, a predetermined dose of antibacterial additive is added to the pre-prepared pigment suspension of one or more pigments, the resulting mixture is homogenized and filtered, followed by the classic steps: pressurizing the viscous solution with well-defined requirements. parameters for damping to a damping machine, and when entering the damping the cellulose solution is mixed in a certain ratio with the suspension, then passes 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 chemical reactions turn into threads.

This is followed by a refining step in which the freshly moistened viscose silk is treated with various solutions to remove residues from the precipitate bath, sodium sulphate and elemental sulfur resulting from the chemical reactions during the moistening.

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 antibacterial additive is from 0.01 to 5% relative to the amount of cellulose in the viscous solution, and in the case of using additive KW 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 viscose 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.

Descriptions of issued patents for inventions № 07.2 / 31.07.2020

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 fed directly for coating.

Explanation 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 fiberization machine.

Figure 4 in the 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.

An exemplary embodiment of the invention

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, which reduces the degree of polymerization. In block 3, the temperature is lowered, and in block 4, the amount of alkalicellulose is dosed to produce 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 batch 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 fed under the pressure to the fiber to the corresponding number of fiber machines 10 in a common tubular collector 36, which is continuously filled with cellulose solution under imposition to prevent 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 moistened cellulose 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 ΊΊ and 28 (Fig. 3) is interrupted and wound only on the receiving mechanism (. During this time, the centrifuge 29 is stopped, the silk 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 ΊΊ 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 coated 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 during the coating.

The resulting semi-finished product is centrifuged, dried, conditioned, rewound and sorted for subsequent grading and packaging as a finished product - blocks 14, 15. 16, 17, 18, and after the eye

Descriptions of issued patents for inventions № 07.2 / 31.07.2020 celebration - 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 table. In order 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 ml.1CHN ₄ C1 19.25 17.40 -temperature ° C 17.0 19.0

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

After coating, the freshly coated antibacterial silk undergoes the treatments to which the silk coated on all spinning machines is subjected, i. these treatments are performed in a common 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.

Descriptions of granted patents for inventions

Claims (7)

Patent claims 1. Process-based method for the production of antibacterial viscose filament silk: treatment of the starting cellulose with a concentrated sodium hydroxide solution to give alkalicellulose, oxidative degradation to reduce the degree of alkaliscellulose polymerisation, cooling and weighing amount thereof for the production of one batch of viscose, subsequent treatment with carbon disulfide to transform the alkali cellulose into cellulose xanthate, dissolving the cellulose xanthate in dilute sodium hydroxide solution, mixing the resulting solution with the solutions from the previous and next batch, , deaeration and re-filtration, after which the already purified cellulose solution containing 8.8% cellulose and 6.4% sodium hydroxide and maturity index 18.5-19.5 under pressure is fed to the wetting machine, wetting by wet method which is carried out as a solution of cellulose and from the local viscose line of the fiberization machine with the help of dosing pumps is transferred to the fiber-optic nozzles and passes through their openings in the fiber-optic bath, where as a result of ongoing chemical reactions, the cellulose from the cellulose solution is transformed into white shiny viscous continuous thread. various solutions for removing the residues from the fiber bath and those resulting from the chemical reactions during the fiber coating, subsequent drying, conditioning, rewinding and grading, characterized in that the antibacterial additive for the production of antibacterial white shiny viscose filament silk is introduced in the ready-to-fiber solution of the cellulose, mix and homogenize with it immediately before its coating on the fiberizing machine. 2. Process for the production of antibacterial colored viscose filament silk, dyed in a mass, based on the processes: treatment of the starting cellulose with a concentrated solution of sodium hydroxide, resulting in alkali cellulose, oxidative degradation to reduce the degree of polymerization of alkalicellulose cooling and weighing the amount necessary for the production of a batch of viscose, followed by treatment with carbon disulfide to transform the alkali cellulose into cellulose xanthate, dissolving the cellulose xanthate in dilute sodium hydroxide solution, mixing the resulting batch with the resulting solution. filtration to remove contaminants, deaeration and re-filtration, after which the already purified cellulose solution containing 8.8% cellulose and 6.4% sodium hydroxide and maturity index 18.5 - 19.5 under pressure is fed to the humidifying machine , wetting by wet method, which is carried out k The mass-dyed cellulose solution from the local viscose line of the fiberization machine is transferred to the fiber-optic nozzles by means of dosing pumps and passes through their openings in the fiber-optic bath, where as a result of the ongoing chemical reactions the cellulose from the cellulose solution is transformed into colored viscous thread, successive treatments with different solutions to remove the remnants of the fiber bath and those resulting from chemical reactions during fiber, subsequent drying, conditioning, rewinding and grading, characterized in that for the production of antibacterial colored dyed in mass viscous filament silk, the suspension of the antibacterial additive and the pigment suspension as an antibacterial color complex are introduced together into the cellulose solution ready for irrigation, mixed and homogenized with it immediately before its irradiation on the fiberization machine. Method according to claims 1 and 2, characterized in that the amount of antibacterial additive introduced, mixed and homogenized in the cellulose solution ready for irradiation immediately before its irradiation on the fiberization machine varies from 0.01 to 5.0% relative to the amount of cellulose in the solution and respectively in the finished antibacterial viscose filament silk. Method according to claims 1, 2 and 3, characterized in that Zinc Pyrithione is used as the antibacterial additive. Descriptions of issued patents for inventions № 07.2 / 31.07.2020 Method according to claims 1, 2, 3 and 4, characterized in that when the antibacterial additive is Zinc Pyrithione and is introduced, mixed and homogenized in the cellulose solution immediately before its coating on the coating machine, the amount of this additive is from 0 , 5 to 3.5% relative to the amount of cellulose in the solution. 6. Antibacterial viscose filament silk - white, shiny and colored dyed in a mass obtained by the method according to all previous claims. Use of an antibacterial additive Zinc Pyrithione according to any one of the preceding claims in a method for the production of antibacterial man-made cellulose fibers, wherein when the additive is added the man-made cellulose fibers acquire permanent antibacterial properties.