RU2298040C1 - Leather finishing process - Google Patents

Abstract

FIELD: leather industry.

SUBSTANCE: method, which is suitable for finishing chrome leathers, comprises consecutively applying coating layers followed by action with low-temperature plasma at generator lamp anodic current intensity 0.2-0.6 A. Action of low-temperature plasma is effected for 180-240 sec at pressure 13.3-26.6 Pa in discharge chamber and consumption of plasma-forming gas (argon) 0.035-0.04 g/sec. Method is implemented on high-frequency plasma installation.

EFFECT: increased adhesion of coating to dry and wet leather, dye penetration depth, resistance to repetitive bends, and strength at better quality of leather.

Description

The invention relates to the leather industry and can be used in the decoration of chrome leathers.

A known method of finishing leather by applying a fixing composition and subsequent radiation by accelerated electrons with an irradiation dose of 8-8.5 Gy (see, for example, AS 1234434).

The disadvantage of this method is a slight increase in the adhesion of the coating to wet skin.

The closest in technical essence and the achieved result is a method for finishing chrome leathers, in which before applying the first layer of coating paint, the skin is exposed to low-temperature nonequilibrium high-frequency plasma in a vacuum chamber for 300-600 s. The effect is carried out at a pressure in the chamber of 53.3-80 Pa and a plasma-forming air flow rate of 0.04-0.06 g / s. In this case, the current strength at the anode of the generator lamp is 0.2-0.6 A. Then, several more layers of topcoat are applied sequentially to the skin (see, for example, patent RU No. 2127763. Bull. No. 8, 20.03.99, IPC ⁶ С14С 9/00, 11/00).

The disadvantage of this method is the low adhesive and strength properties of the skin.

The objective of the invention is to improve the adhesion, stability of the coating of chrome leathers, increase the strength of the skin and improve its quality.

This object is achieved in that the method of finishing chrome leather involves the sequential application of all coating layers when exposed to low-temperature plasma with a current strength of 0.2-0.6 A on the anode of the generator lamp, after applying all layers of the coating, the skin is exposed to low-temperature plasma for 180- 240 s at a pressure in the discharge chamber of 13.3-26.6 Pa and a flow rate of plasma-forming gas - argon 0.035-0.04 g / s.

The skin introduced into the plasma of a high-frequency discharge, relative to the plasma, acquires a negative charge. On opposite sides of the plate, a positive charge layer is alternately created. At each point in time, the charges of different sides of the plate differ from each other. And since the material being processed - leather refers to dielectrics, the system "positive charge layer - skin - positive charge layer" can be considered as a capacitor. Therefore, inside the skin there is an electric field, its intensity is sufficient for the breakdown of gas in micropores.

Three processes make the greatest contribution to the modification of the outer surface: the recombination of ions and the transfer of energy acquired in the surface charge layer near the surface of a solid body, the thermal effect, and the recombination of ions and thermal effect to the “bulk” modification. The heat flux density does not exceed 8 · 10 ³ W / m ² , and the energy of the ions bombarding the surface reaches 90 eV. Modification occurs not only on the surface layers at the geometric boundary, but also throughout the skin.

After exposure to low-temperature plasma, the fibrous structure of the dermis changes. An increase in the ordering of the amorphous phase and an increase in the percentage of the crystalline phase leads to an increase in the strength of the skin, however, the skin does not acquire stiffness, since the process of cracking proceeds in parallel with the hardening process, in which the compactness of the interweaving of the structural elements of the skin decreases, their mobility and ability to move under the influence of bending forces. An increase in the interaction surface due to fiber splitting and an increase in skin porosity leads to an increase in the adhesion of the coating to the skin.

The method is carried out on a high-frequency plasma installation. The installation (drawing) contains a gas supply system (1), a vacuum chamber (2), electrodes (3), a pumping system (4), a vacuum unit (5), a discharge chamber (6), a cooling system (7), and a high-frequency (HF) generator (8), vacuum pipeline (9).

The method is as follows.

In a vacuum chamber (2), skin samples are placed in the gap between parallel vertically arranged electrodes (3) along the plasma-forming gas stream. Preliminary pumping of air from the vacuum chamber (2). Working gas is introduced into the vacuum chamber (2). By adjusting the valve connecting the vacuum chamber (2) to the pumping system (4), the set pressure is set. When high-frequency voltage is applied to the electrodes (3) in the discharge chamber (6), a plasma stream is formed, a processing tool, by heating the plasma-forming gas to a plasma state.

The plasma treatment mode is controlled by changing the flow rate of the plasma-forming gas 0.035-0.04 g / s, the current on the generator lamp 0.2-0.6 A, the pressure in the discharge chamber 13.3-26.6 Pa, the exposure time of the plasma 180- 240 s. Argon is used as a plasma-forming gas.

The research results of the proposed method for finishing chrome leathers and its indicators of physical and mechanical properties are shown in table 1. Analysis of the data presented in the table shows that the method of finishing chrome leathers due to exposure to low-temperature plasma after coating will increase the adhesion, coating stability, strength of chrome leathers and improve its quality. The most optimal mode for finishing chrome leathers is exposure for 180-240 seconds, at a pressure in the discharge chamber of 13.3-26.6 Pa, the consumption of plasma-forming argon is 0.035-0.04 g / s. The method of finishing leather beyond the boundaries of these values leads to a deterioration in physical and mechanical properties.

Table 1 Installation Modes Physical and mechanical properties Adhesion of the coating, N / m Dye penetration depth, microns Coating stability
number of bends Breaking load
tensile 10 MPa to dry skin to wet skin Prototype 341.3 170.3 173 39,000 21.6 Plasma exposure time, s 150 600.8 193.8 218 41000 23.1 180 920.0 230,0 240 45000 24.5 240 850.5 210.7 222 42000 23.7 300 540.2 187.1 213 40,000 22.8 Gas consumption, g / s 0,03 720.8 198.3 220 41000 23.8 0,035 910.2 228.8 238 44000 24.3 0.04 880.7 223.9 241 45000 24.8 0.06 450.5 183.6 211 39,000 22.9 Chamber pressure, Pa 10.0 680.7 188.1 221 42000 23.3 13.3 900.8 231.2 239 44000 24.6 26.6 890.1 221.9 229 43000 23.9 50,0 320.9 181.4 212 39,000 22.5

The adhesion of the coating is determined according to GOST 939-88, Note 6 "Method for determining the adhesion of emulsion and nitroemulsion coatings to the skin."

The penetration depth of the dye is determined using a scanning electron microscope REMMA-202M according to the methodology of a laboratory workshop on chemistry and technology of skin and fur by A.A. Golovteeyev, D.A. Kutsidi, L.B.Sankin. M .: Legprombytizdat, 1987, pp. 250-258.

The tensile tensile load is determined according to GOST 938.11-69.

The resistance of the coating to the skin to repeated bending is determined according to GOST 138-68.

The advantages of this method compared to the prototype are an increase in the adhesion of the coating to dry and wet skin, the penetration depth of the dye, increasing the resistance of the coating to repeated bending, strength and quality of the skin.

Claims (1)

A method of finishing leather, including the sequential application of all coating layers when exposed to low-temperature plasma with a current strength of 0.2-0.6 A at the anode of the generator lamp, characterized in that after applying all coating layers, the skin is exposed to low-temperature plasma for 180-240 s at a pressure in the discharge chamber of 13.3-26.6 Pa and a flow rate of plasma-forming gas - argon 0.035-0.04 g / s.