CZ229493A3 - Bleaching process and increasing of adhesion of fibrous materials to dyestuffs - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a method of bleaching and increasing adhesion of fabrics to dyes. The fibrous material may be a textile material or paper primary, optionally recycled or loose, or processed into a length or sheet formation.

BACKGROUND OF THE INVENTION

Bleaching of fibrous material is typically accomplished by: chlorination. This method is ecologically harmful and expensive in terms of the cost of the amount of water used.

The fibrous material should be treated before dyeing. Increased. adhesion can be achieved, for example, chemically, or by adjusting capillary effects with nonwovens.

For the treatment of textiles, ionizing radiation is also used, possibly in interaction with / sulfur and chlorine. . It is also known to treat a textile material by passing the textile material through a silent discharge plasma for 1 to 200 seconds. Plasma consists of electrons, positive ions and a neutral gas such as argon, neon, hydrogen, nitrogen, oxygen, carbon dioxide, ammonia, chlorine, or mixtures thereof. Preferably, the material may be exposed to a cold plasma feasible in a pressure range of 10 Pa to 10 Pa at a frequency of 10 to 10 Pa. This procedure is preferred. in particular to increase the adhesion of the polyester fabrics to the rubber and to increase the wettability of the polyester and the polymethacrylate. A disadvantage of this process is the impaired feel of the fiber material.

SUMMARY OF THE INVENTION

The method of bleaching a fibrous material and enhancing its adhesion to dyes consists in treating the fibrous material with a gas-activated electric discharge generated at atmospheric pressure. The fibrous material can be treated with a plasma of a silent electric discharge in the gas at atmospheric pressure. nebí). a gas stream activated in the plasma of a high pressure glide discharge.

It is preferable to treat the fibrous material with a stream of gas activated in a water mist enriched plasma for 10 to 20 s. '

Plasma bleaching means, by increasing the whiteness of the fibrous material, also an increase in the sorption properties of the fibers in the flat hand of the textile fibers when treated in their / discharges and at unchanged soak. treatment in the "plasma stream". .

Plasma treatment eliminates ecologically harmful chlorination and saves water. The cost of bleaching in this way is very low. .

Overview of pictures

An apparatus for treating fibrous material in a plasma of a silent discharge is shown in FIG. Fig. 2 shows an apparatus for treating material in a plasma activated gas stream.

Examples, embodiments.

Device and method of fiber treatment. silent discharge plasma material:.

Two plates. The insulator 1, most commonly glass, of FIG. 1, is coated or plexiglass with an electrically conductive layer on one side. 2. Both boards are placed in parallel in a special one

5 mm, the electrically conductive layers being. .outwardly created. spaces; The conductive layers are supplied with a high voltage of 13 to 20 kV of either technical or higher frequency, for example 500 Hz 3., A silent discharge occurs in the gap between the plates, which is acoustically manifested by slight cracking. The fibrous material 4 is slowly drawn through the gap between the plates so that it is perfectly and homogeneously distributed. The treatment time is given by the speed of movement of the material in the gap between the insulating electrodes. The treatment is carried out at atmospheric pressure in air. Other gases may also be used, but the entire device must be located in a sealed chamber 5 flowing through the used gas 6,7.

Apparatus and method for treating fibrous material in a gas stream activated in a plasma of a high pressure glide discharge:

The two fork-shaped metal electrodes 2, Fig. 2, are approximately 3 mm apart at the point of maximum approach. The electrodes are supplied with a high voltage of 10 to 15 kV of technical or increased frequency (tested at 500 MHz). In the gap between the electrodisplacement-high-glow-smolder-flux -4, the heat convection slowly slides over the forked electrodes . If there is a gap between the electrodes. 2, the gas 3 (most often air) is injected in an amount of 10 to 30 l / s, the discharge is entrained by the flowing air and acquires the character of a spike discharge. The neutral gas temperature in this discharge does not exceed 10 ° C. In the gas stream which has passed through the discharge, the fibrous material 4 is displaced at a distance of about 5 cm above the discharging discharge. The treatment time of the material in the gas stream is 10 to 30 seconds. The efficiency of the treatment is increased when using gas (air) mixed with water mist.

Example 1.

The woolen comb opened in the form of a web was exposed between two specially designed electrodes (Fig. 1) to a silent electric discharge, a voltage between the electrodes of 15 kV exposure time of plasma 90 with moisture treated 20, 40, 65. 64, 70

The whiteness evaluation was performed according to TAUBE on the basis of remitoinometric measurements on a DATACOLOR 3890 spectrophotometer. The results are as follows:

Moisture Softness '%' Tension . kV time application with zrněná in whiteness % change in strength: color  % '58 15 Dec . 90 - 2,2 + 38.1 20 -64 15 Dec . 90 + 14.4 + * 13.6  70 15 Dec . 90. ’ . - 0,1  + 12.3 58 · 15 Dec ⁹⁰ + 33.0 ; _____ + 25,6 ...... 40 64 15 Dec 90 + 13.3. + 9.0 70 ^{15 Dec} 90 0.5 +. -3,2- 58 15 Dec 90 + 40.1 + 14.1 .65 64 15 Dec 90 + 20.1 + 7.8 70 15 Dec 90 + 3,3 + . 1.5.

The treatment of woolliness in the plasma of a silent discharge is very well applicable for industrial use, especially since it operates at atmospheric pressure, unlike previously published and patented devices operating in the low pressure field.

Example 2.

The woolen elongated in the form of a web was exposed to the current, the plasma. air entrained between two specially designed electrodes 2 in a water-enriched air environment.

comb humidity 65%

The whiteness evaluation was performed according to TAUBE, based on

-3-ritometric measurements on the DATACOLOR 3890 spectrophotometer. The results are as follows:

Tab. II. Results of treatment applied in plasma stream.

Softness Moisture Time Change Change in color strength in whiteness AFTER 7 days after exposure exposure % with % % %. 10 + 12.6 + 28.6 + 14.5 58 65 20 May + 6,9 + 18.3 + 62.0 10 + 8.5 - 3,4 + 46.3 64 65 20 May + 4,5 + 5.1 + 39.3 10 + 3,4 + 10.1 . + 8.7 6.5 20 May + 4,1 + 5,7 ' + 11.6 _ _ _ ___ _ _ _ _ _ _ - -.7-

The treatment in the gas stream activated in the plasma of the glide discharge is fully usable for industrial use. During the treatment, free radicals are formed on the surface of the fibrous material as evidenced by the measurement of electron paramagnetic resonance spectra. This type of treatment is somewhat more demanding to ensure operational safety (increased possibility of ignition of fibrous material during treatment.

The evaluation of the treatment effect was determined by means of macroscopically measurable properties such as:

The touch is unchanged or slightly deteriorated depending on the fineness and moisture of the fibers. At lower fineness, the silent discharge plasma treatment has a negative effect on the touch, which decreases with increasing humidity. Increasing voltage at the electrodes upon silent discharge affects the touch negatively. There was no change in feel when the fiber was treated in the glide-discharge plasma stream.

Whiteness was measured on a Datacolor 9890 spectrometer and calculated by Taube. Whiteness is demonstrably increased by the above treatment. With increasing fineness, the bleaching ability of the treatment decreases somewhat. Increasing moisture increases the bleaching effect of the treatment. With regard to the bleaching capability and to the touch, the fiber treatment in a silent discharge plasma seems to be the optimal voltage at the electrodes of 15 kV, the plasma application time of 90 seconds for a standardized 65% comb.

j The uniformity of the treatment - eventual damage - was also tested using the company standard, based on the coloring of specially selected dye Drimalantúrkis blau G and C.i.Acid blue 129.

The color loss was compared with ethanol and marked with a scale

1-3 (1 disturbed, 2 partially disturbed, 3 no signs of disturbance, applicable to all shades of coloring). ..... _: . riálu. and, on even ... opening. comb to shape cobwebs before treatment.

The dyeability - sorption properties - were evaluated on the basis of measuring the remitometric properties of combs stained under standard conditions with dye Drimalantúrkis at 1% concentration. The measurement was performed on a Datacolor 3890 spectrophotometer. The color deviation was calculated from the integrated remission values in the 400-600 nm range.

. Damage - was checked on the basis of caustic solubility values - determined according to ISO 3072.

A ·,. '* Industrial Applicability! The invention is applicable in the textile and paper industry.

Claims (4)

PATENT CLAIMS A method for bleaching fibrous material and increasing its adhesion to dyes, characterized in that the fibrous material is treated with a gas-activated electric discharge excited at atmospheric pressure. 2. The method of item 1, v, y. of . n. a. u. u. i. c. i. ,. p. e. . i. m., wherein the fibrous material is treated with a plasma of a silent electric discharge in the gas at atmospheric pressure. 3. The method of item 1, wherein the fibrous material is treated with a gas stream activated in the plasma of a high pressure glide discharge. 4. A method according to any one of claims 1 to 3, characterized in that the fibrous material is treated with a gas-activated gas discharge at atmospheric pressure, enriched in a water mist for 10 to 20 s.