RU2488600C1 - Method for surface modification of polypropylene material - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to textile and chemical industry. Described is a method for surface modification of polypropylene material by fluorination once. Modification is carried out at room temperature for 25-30 minutes with a gaseous mixture. The gaseous mixture contains 8-10 vol. % fluorine, 8-10 vol. % oxygen and 80-84 vol. % inert gas. The inert gas is nitrogen or helium.

EFFECT: endowing the material with a bacteriostatic property and low power consumption of the process.

6 ex, 1 tbl

Description

The invention relates to the textile and chemical industries, namely to surface modification of polypropylene materials in order to give them special properties.

State of the art

It is known that surface modification of polypropylene materials provides them with various special properties, in particular antimicrobial, including bacteriostatic properties. Surface modification can be carried out in various ways.

Known methods for modifying the surface of a material from polypropylene (Patents of the Russian Federation 2223982, publ. 02.20.2004; RF 2288239, publ. 11/27/2006), which include activation of the surface of a material immersed in a solution under a glow discharge between the electrolyte solution and the anode located above the solution at atmospheric pressure and simultaneous or subsequent processing of the activated surface with biologically active substances. Although the technical objective of these methods is to give the polypropylene material high catalytic activity, their use also allows you to create medical materials with a local therapeutic effect (Golubchikov O.A., Ageeva T.A., Titov V.A. Surface modification of popipropipene with bioactive compounds // Russian Chemical Chemistry University (J. Russian Chemical Chemistry Society named after D.I. Mendeleev), 2004, vol. XLVIII, No. 4, pp. 166-172). However, the disadvantages of applying biologically active substances to a polypropylene material pre-activated by a plasma-solution method are the energy intensity of the methods, the need to use expensive biocidal preparations and special equipment not manufactured on an industrial scale.

A known method of imparting bacteriostatic properties to polypropylene materials intended for the manufacture of filters. It consists in the activation of polypropylene material with a low-temperature plasma of low pressure in argon, the impregnation of polypropylene fibers with a colloidal solution of silver nanoparticles at a concentration of 10 g / l and the fixation of silver nanoparticles due to the reprocessing of polypropylene material with a low-temperature plasma of low pressure in argon (Abdullina V.Kh., Sergeeva EA, Pankova EA. And others. The effect of plasma activation on the fixation of silver nanoparticles on the surface of polypropylene fiber // Bulletin of Kazan technologist University of Technology, 2009, No. 3, pp. 53-56). However, the method is complicated due to the need for three-stage processing and the creation of reduced pressure. In addition, the method is characterized by high energy intensity (high energy consumption for plasma generation) and material intensity (high consumption of expensive colloidal silver solution). There is also a method of imparting antimicrobial properties to polypropylene non-woven materials by modifying them with copper and silver cations, which are introduced by ion-exchange substitution into a polypropylene material previously activated in a plasma-solution system at atmospheric pressure in air (V.A. Titov. Physicochemical processes in plasma – polymer and plasma – solution – polymer systems // Abstract of Diss. ... Doctorate in Physics and Mathematics, IGHTU, Ivanovo, 2009, 32 pp.). This method is also energy and material intensive, although to a lesser extent than the previous one, since atmospheric pressure plasma generation requires less energy consumption than low pressure plasma generation. In addition, the method requires the use of special equipment not manufactured on an industrial scale.

There is also known a method of chemical modification of polypropylene fibrous materials with antimicrobial substances (O.V. Gornukhina, N.E. Kulyashova, I.A. Vershinina Polypropylene materials chemically modified with antimicrobial substances // Bulletin of Universities. Chemistry and Chemical Technology, 2011, issue 54 No. 11, pp. 100-102). The method consists in chemical activation of the surface of polypropylene material with a 20% aqueous solution of sodium hydroxide in the presence of iron (II) sulfate at a boiling point for 2 hours, followed by treatment with a 2% solution of silver nitrate at a temperature of 17 ± 2 ° C for 12 hours and rinsing with distilled water. The modified material has, in comparison with the initial, pronounced antimicrobial effect. The disadvantages of the method include the long processing time, the energy consumption of the modification process, which is carried out at 100 ° C for 2 hours, as well as a significant loss of strength of the polypropylene fibrous material.

Closest to the invention, the technical essence is a method of surface modification of crystalline and amorphous thermoplastics and rubbers (Patent SU No. 1816773, publ. 05.23.1993), which provides for the treatment of polymeric materials with gaseous fluorine mixed with an inert gas in 2-5 stages, between which carry out heat treatment: for crystalline thermoplastics at a temperature of 25-35 ° C below the melting point, for amorphous thermoplastics at a temperature lying in the range from the glass transition temperature to a temperature of 10 ° C below it, for rubbers - at 40-100 ° C. The total processing time is 1-60 minutes. This modification allows to reduce the permeability of polymeric materials for low molecular weight substances and increase their mushroom resistance.

However, the polymer modified by this method does not inhibit the development of gram-positive and gram-negative bacteria that are dangerous for humans. Moreover, the method is rather complicated, since it consists of three stages, each of the two fluorination stages separated by heat treatment includes several operations. These include loading material into the reactor, pumping air out of the reactor, filling the reactor with a fluorine-containing mixture. In addition, this method is energy intensive, because heat treatment between fluorination is carried out at a temperature of 130-150 ° C.

SUMMARY OF THE INVENTION

The inventive task was to find a simpler method of surface modification of a polypropylene material by fluorination with fluorine gas in a mixture with an inert gas at room temperature, which would give the material bacteriostatic properties and would have less energy intensity.

The problem is solved by the method of surface modification of polypropylene materials by fluorination with fluorine gas in a mixture with an inert gas at room temperature, in which fluorination is carried out once for 25-30 minutes with a gas mixture containing,% vol .: fluorine - 8-10, oxygen - 8- 10, inert gas - 80-84.

The technical result of the invention is that polypropylene filaments and non-woven material acquire the property of inhibiting the development of gram-positive and gram-negative bacteria, which allows you to turn the fibrous material into a barrier to pathogenic microflora. For patients, especially postoperative, nosocomial infection is extremely dangerous. The problem of ensuring the sanitary-hygienic and infectious safety of medical staff and patients is currently being solved mainly by the use of disposable clothes and linen made of polypropylene non-woven material and subjected to sterilization at the final stage of manufacture. However, the use of disposable medical clothing and linen not only sterile, but possessing antimicrobial barrier properties, gives an even more significant effect. killing microorganisms falling on them. The method is much simpler and less time consuming, because instead of two stages of fluorination, each of which consists of several operations, and the stage of heat treatment, provides only one stage of fluorination. In addition, the method is characterized by low energy consumption, because eliminates the need for heat treatment. This method does not lead to a decrease in the strength characteristics of fibrous materials. Its significant advantage is also the absence of the need for special expensive antimicrobial agents, which, when exposed to human skin, often cause allergic reactions.

Information confirming the ability to reproduce the invention.

To implement the method, you can use the following substances:

- fluorine;

- oxygen;

- an inert gas, for example nitrogen, helium.

The proposed method can modify the polypropylene yarn, fabric, needle-punched and thermally bonded non-woven material, including spunbond, used for the production of disposable medical clothing.

Direct gas-phase fluorination of polypropylene fibrous materials was carried out in a closed reactor equipped with gas valves allowing the system to be evacuated using a foreline pump to a residual gas pressure of 4-7 Pa. To neutralize the toxic fluorine and the reaction product, hydrogen fluoride, a special trap filled with alumina and sodium fluoride was used. All parts of the reactor in contact with fluorine and its mixtures are made of stainless steel, steel-3 and teflon. The sample was placed in a closed reactor, the air from which was pumped out to a residual pressure of 4-7 Pa and filled with a fluorine-containing mixture to a pressure of 0.9-1.0 MPa. After 25-30 min of treatment, the fluorinating mixture was removed from the reactor and the modified polymer sample was recovered. The pressure of the mixtures used for fluorination was measured with an exemplary vacuum gauge. To control the pressure of the residual gases, a VIT-2 ionization-thermocouple vacuum gauge with a PMT-2 thermocouple converter was used.

The properties of the polypropylene material modified by the prototype method and the claimed method were controlled the same way:

To evaluate the antimicrobial properties, we used a method that is a simplified version of the counting microbiological test ASTM E2149 (ASTM E2149-10 Standard Test Method for Determining the Antimicrobial Activity of Immobilized Antimicrobial Agents Under Dynamic Contact Conditions. USA, 2001). This test is based on counting the number of microbial colonies formed during 24-hour contact of the crushed fibrous material, subjected to a non-migrating preparation undergoing modifying treatment, with physiological saline, into which a certain number of microbial colonies are added in suspension. In order to avoid errors in counting the colonies of microorganisms and to shorten the counting time, the number of formed colonies was evaluated photometrically by the change in the turbidity of the solution, which increased with the growth of microorganisms. For this, comparing the optical density of the solutions, the percent growth of the culture was determined. According to the percentage of culture growth, the experimental results were divided into 4 groups: 100% - lack of antimicrobial effect; more than 10% - insufficient antimicrobial effect; 1-9% - good antimicrobial effect; less than 1% - a very good antimicrobial effect. As test gram-negative and gram-positive microorganisms, Escherichia coli Escherichia coli) and Staphylococcus aureus (Staphylococcus aureus) were used.

Example

A sample of polypropylene material was placed in a sealed reactor, the air from which was pumped out to a residual pressure of 6 Pa and filled with a fluorine-containing mixture of 9% fluorine, 9% oxygen, 82% nitrogen to a pressure in the reactor of 0.9 MPa. Samples were held in the reactor at room temperature for 30 minutes. Then the fluorinating mixture was removed from the reactor and the modified polypropylene material was removed from it.

The properties of polypropylene fibrous materials modified by the prototype method, as well as by the claimed method for various duration of fluorination and the composition of the gas mixture are shown in the table.

Table Properties of polypropylene thermally bonded non-woven material with a surface density of 30 g / m ³ , modified under various conditions No. p / p The number of stages of processing The processing time, min The composition of the gas mixture % culture growth / antimicrobial effect 1. unmodified
bathroom - - - 100 / lack of antimicrobial effect 2. one 25 9% fluorine, 9% oxygen, 82% nitrogen 3 / good antimicrobial effect 3 one thirty 9% fluorine, 9% oxygen, 82% nitrogen 0 / very good antimicrobial effect four. one thirty 8% fluorine, 8% oxygen, 84% nitrogen 4 / good antimicrobial effect 5. one thirty 10% fluorine, 10% oxygen, 80% nitrogen 4 / good antimicrobial 6 prototype 2 (fluorination) + 1 (heat treatment) 35 15% fluorine, 85% nitrogen 86 / lack of antimicrobial effect

Claims (1)

The method of surface modification of a polypropylene material by fluorination with fluorine gas in a mixture with an inert gas at room temperature, characterized in that the fluorination is carried out once for 25-30 minutes with a gas mixture containing, vol.%: Fluorine 8-10, oxygen 8-10, inert gas 80-84.