RU2357785C1 - Filtering material, method of its production and product on its base - Google Patents

Abstract

FIELD: textile, paper.

SUBSTANCE: invention relates to fibrous filtering materials. Filtering fibrous material is proposed which is produced by electrostatic formation from a solution of polymer mixture - sterol copolymer with acrylonitrile and polyurethane with their weight relation of (50-95):(50-5) respectively, diametre of 1-10 mcm; the material is characterized by the unit area weight of 2070 g/m² and aerodynamic resistance of 3-30 Pa under the air flow speed of 1 cm/s. Method of the material production and respiratory personal protective gear made from it are proposed as well.

EFFECT: providing for effective filtering material with improved physical and chemical parametres.

5 cl, 1 dwg, 2 tbl, 4 ex

Description

The invention relates to the field of production of fibrous filter materials FP (Petryanov Filters) used to protect the environment, as well as respiratory organs from toxic aerosols.

Known filter material obtained by electrospinning from a copolymer of styrene with acrylonitrile with a fiber diameter of 1-10 μm from a dope solution containing dichloroethane, electrolytic additives and solvents from the series: acetone, or methyl ethyl ketone, or ethyl acetate, or butyl acetate and having a surface density of 20-80 g / m ² , aerodynamic drag 3-60 Pa at an air flow rate of 1 cm / s (RU 2182511, 05.20.2002).

Also known is the material obtained by electrostatic molding from a solution of a styrene-acrylonitrile copolymer in a mixture of ethyl acetate and butyl acetate at a weight ratio of 1/9 to 9/1, respectively, the solution containing an additive of high molecular weight polymethyl methacrylate in an amount of 0.001-0.01 wt.% (RU 2248838, 03/27/2005).

The disadvantage of these technical solutions is the low physical and mechanical properties, which significantly impair the manufacturability of the respirator assembly.

Also known filtering material obtained by the method of electrospinning, containing 50-90% wt. fibers from a copolymer of styrene and acrylonitrile and 10-50% wt. fibers made of chlorinated polyvinyl chloride with the addition of not more than 10% wt. nitrile butadiene rubber by weight of chlorinated polyvinyl chloride, with a fiber diameter of 1-10 microns. (RU 2283164, 09/10/2006).

The disadvantage of this technical solution is the complexity of the process due to the use of two spinning solutions and the inability to use it in the electric centrifugal method of forming fibrous material. In addition, there is currently no chlorinated polyvinyl chloride on the market that meets sanitary standards for respiratory filter media.

Closest to the proposed material is a two-layer filter material obtained by electrospinning, consisting of fibers with a diameter of 1.5-3 microns and 3-5 microns made of a solution of a copolymer of styrene with acrylonitrile or a triple copolymer of styrene with acrylonitrile and methyl methacrylate in ethyl acetate, butyl acetate or mixtures thereof, the solution containing an additive of high molecular weight polymethyl methacrylate in an amount of 0.001-0.01 wt.%. (RU 2267347, 01/10/2006).

The disadvantages of the prototype are low physical and mechanical properties of the filter material, which significantly impair the manufacturability of the respirator assembly. In addition, the two-layer structure of the material does not allow reproducing it by electro-aerodynamic and electrocentrifugal methods.

The objective of the present invention is to increase the physico-mechanical properties of the filter material and products based on it, to improve the process of electrospinning of the fibers by increasing the spinnability of the solution, which allows to obtain the filter material by electrocapillary, electroaerodynamic and electrocentrifugal methods.

The problem is solved by the described filtering fibrous material obtained by electrostatic molding from a solution of a mixture of polymers: a copolymer of styrene with acrylonitrile and polyurethane, with their mass ratio (50-95) :( 50-5), respectively, with a diameter of 1-10 microns, while the material is characterized by an area mass of 20-70 g / m ² and an aerodynamic resistance of 3-30 Pa at an air flow rate of 1 cm / s.

The problem is also solved by the described method for producing filtering fibrous material by electrostatically molding fibers from a solution of a polymer mixture containing a copolymer of styrene with acrylonitrile and polyurethane in an organic solvent with a dynamic viscosity of 1-30 poise and a specific conductivity of 10 ^-4 -10 ^-7 Ohm ^-1 · cm ^-1 , with the following content of components, wt.%:

styrene-acrylonitrile copolymer 10-28 polyurethane 0.5-14 electrolytic additives selected from iodides or bromides tetraalkylammonium 0.01-0.5 organic solvents selected from a number: dichloroethane, ethyl acetate, butyl acetate, ethanol rest

Polyurethane having the following characteristics is preferably used:

density, g / cm ³ 1,2 viscosity in 10% toluene solution, MPa · s 400-800 softening temperature, ° C fifty crystallization rate, min thirty

Forming is carried out by electrocapillary, electroaerodynamic or electrocentrifugal methods in an electrostatic field with a potential difference of 10 to 140 kV.

The problem is also solved by the described individual respiratory protective equipment containing a fibrous filter material, a substrate and a protective layer that contains the material described above, obtained by the method described above.

The technical result achieved can be explained by the fact that, as a result of mixing the styrene-acrylonitrile copolymer and polyurethane in a solution, more flexible fibers are formed that improve the physicomechanical properties of the filter material. In addition, solutions containing the claimed polymers have the best spinning ability, which allows the process of electrospinning by electrocapillary, electroaerodynamic or electrocentrifugal methods.

The following are specific examples of obtaining the claimed material and products based on it.

Example 1

Prepare a 25% spinning solution of styrene-acrylonitrile copolymer (SAN) with the addition of polyurethane (PU) at a ratio of 90/10 in ethyl acetate (EA) with the addition of 5% ethanol with a dynamic viscosity (η) of 4.9 poise; the specific conductivity of the solution (λ) was adjusted to 5 · 10 ^-6 Ohm ^-1 · cm ^-1 , introducing 0.2% tetrabutylammonium iodide (TBAI).

Then, fibrous material is formed by the electrocapillary method with a potential difference of 70 kV and a volumetric flow rate of the solution of 3 · 10 ^-3 cm ³ / s per capillary.

On a metal grounded electrode, a fibrous layer is obtained from a mixture of ultrafine fibers with a diameter of 5-7 μm, a unit mass of 45 g / m ² and an aerodynamic resistance of 6 Pa.

Example 2

Prepare a 15% spinning solution of a styrene-acrylonitrile copolymer with the addition of polyurethane at a ratio of 80/20 in dichloroethane (DCE) with the addition of 3% ethanol with a dynamic viscosity of 2.5 poise; adjust the conductivity of the solution to

1.5 · 10 ^-6 Ohm ^-1 · cm ^-1 , introducing 0.02% TBAI.

Then, fibrous material is formed by the electro-aerodynamic method with a potential difference of 120 kV and a volumetric flow rate of the solution of 1.2 · 10 ^-2 cm ³ / s per nozzle.

On a metal grounded electrode, a fibrous layer is obtained from a mixture of ultrafine fibers with a diameter of 2-5 μm, a unit mass of 35 g / m ² and an aerodynamic resistance of 11 Pa.

Example 3

Prepare a 20% dope solution of a styrene-acrylonitrile copolymer with the addition of polyurethane at a ratio of 85/15 in dichloroethane with the addition of 3% ethanol with a dynamic viscosity of 5.8 poise; adjust the conductivity of the solution to 3.5 · 10 ^-6 Ohm ^-1 · cm ^-1 , introducing 0.03% TBAI.

Then, fibrous material is formed by the electric centrifugal method with a potential difference of 80 kV and a volumetric flow rate of the solution of 5 cm ³ / s per spray plate.

On a metal grounded electrode, a fibrous layer is obtained from a mixture of ultrafine fibers with a diameter of 3-5 μm, a unit mass of 50 g / m ² and an aerodynamic resistance of 14 Pa.

An individual respiratory protective device is made from the obtained materials on a KG-1 semiautomatic device as follows.

Example 4

The filter material on a medical gauze substrate (1) is cut in the form of round blanks. A protective frame made of finished gauze (1) is applied to the filter material. In addition, braided elastic (2) with an aluminum plate (3), a figured spacer (4) and a headband (6) are inserted. The assembled semifinished product is refilled in the KG-1 semiautomatic device, in which thermo crosslinking with polyvinyl acetate beads takes place along the respirator circuit - to the sealer (5) (see drawing).

Data on the composition of the spinning solutions, the operational properties of the filter materials and products from them are summarized in tables 1, 2.

Table 1 No. The composition of the solution, wt.% Solution characteristics SAN PU DCE EA BA Ethanol TBAI η, poise λ, Ohm ^-1 cm ^-1 1. The electrocapillary method of 70 kV 1.1. 22.5 2.5 - 69.6 - 5 0.20 4.9 5 · 10 ^-6 1.2. 27 1,5 - 66,4 - 5 0.10 12,2 2 · 10 ^-6 1.3. 12 10 - 65.7 7 5 0.40 15.1 3 · 10 ^-5 2. Electro-aerodynamic method 120 kV 2.1. fourteen 2 80,99 - - 3 0.01 3,1 6 · 10 ^-7 2.2. 12 3 81.98 - - 3 0.02 2.7 1.5 · 10 ^-6 2.3. 10 four 82.97 - - 3 0,03 5.5 1.5 · 10 ^-6 3. Electrocentrifugal method 80 kV 3.1. fourteen 2 80,99 - - 3 0.01 3,1 6 · 10 ^-7 3.2. 17 3 76.97 - - 3 0,03 5.8 3.5 · 10 ^-6 3.3. 10 four 82.97 - - 3 0,03 5.5 1.5 · 10 ^-6

table 2 Material characteristic Material No. according to table 1 1.1 1.2 1.3 2.1 2.2 2.3 3.1 3.2 3.3 The diameter of the fibers, microns 5-7 7-9 1-2 2-5 2-5 2-4 2-5 2-5 2-4 Mass units area, g / m ² 45 65 25 40 35 thirty 40 fifty thirty Aerodynamic resistance at 1 cm / s, Pa 6 8 28 16 eleven 13 16 fourteen 12 Breakthrough Ratio,% 0.02 0.01 0.05 0,03 0.04 0.5 0,03 0.02 0.4 Elongation at break 0.5 0.4 0.9 0.4 0.5 0.7 0.4 0.5 0.6

Thus, as can be seen from the above examples, the filter material obtained by the claimed method has an increased elongation at break due to the introduction of an elastic additive into the fibers compared to a material made from a styrene-acrylonitrile copolymer without additives. At the same time, the filtering properties are maintained at a high level, which allows us to produce highly effective personal respiratory protection equipment.

Claims (5)

1. The filtering fibrous material obtained by electrostatic molding from a solution of a polymer mixture, including a styrene-acrylonitrile copolymer, characterized in that the fibers are made from a mixture of styrene-acrylonitrile copolymer and polyurethane, with their mass ratio (50-95) :( 50-5 ), respectively, with a diameter of 1-10 microns, while the material is characterized by a mass per unit area of 20-70 g / m ² and aerodynamic resistance of 3-30 Pa at an air flow rate of 1 cm / s. 2. A method of obtaining a filtering fibrous material by electrostatically forming fibers from a solution of a polymer mixture containing a styrene polymer with acrylonitrile in an organic solvent with a dynamic viscosity of 1-20 P and a specific conductivity of 10 ^-4 -10 ^-7 Ohm ^-1 · cm ^-1 , characterized the fact that the molding is carried out from a solution additionally containing polyurethane in the following components, wt.%:
styrene-acrylonitrile copolymer 10-28 polyurethane 0.5-14 electrolytic additives selected from tetraalkylammonium iodides or bromides 0.01-0.5 organic solvents selected from among: dichloroethane, ethyl acetate, butyl acetate, ethanol rest 3. The method according to claim 2, characterized in that the use of polyurethane having the following characteristics:
density, g / cm ³ 1,2 viscosity in 10% solution of toluene, MPa · s 400-800 softening temperature, ° C fifty crystallization rate, min thirty 4. The method according to claim 2, characterized in that the molding is carried out by the electrocapillary, electroaerodynamic or electrocentrifugal method in an electrostatic field with a potential difference of 10 to 140 kV. 5. An individual respiratory protective device containing a fibrous filter material, a substrate and a protective layer, characterized in that it contains the material described in claim 1, obtained by the method described in claim 2.