JPH0361792B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for plasma processing fabric. Currently, fabrics such as woven and knitted fabrics, non-woven fabrics, and composite coating materials thereof are used in a wide range of fields, whether for materials or clothing, and have become extremely important base materials. However, these base materials have various drawbacks, and many processing agents and finishing agents are used to compensate for these drawbacks. For example, the generation of static electricity, lack of adhesion, lack of printability, lack of color development in dyed products, and the improvement of our society by investing a lot of technology and effort into surface modification such as adding water repellency and stain resistance. It has become a useful base material. One of the problems when applying these post-processing agents is that their durability is insufficient, and if they are not applied extremely thin and uniformly, defects in texture and appearance will occur, so technical difficulties must be constantly faced. It was impossible. In order to solve the above problems, a highly durable surface modification method has been developed in which fabrics are treated in low-temperature plasma, and this technology is also attracting attention as a technology that can reduce pollution using dry systems. When this method, which is generally called plasma processing, is commercialized in practical terms, unexpected problems have been discovered. Originally, the surface modification should be uniform and stable, but
When passing a fabric through a glow discharge, it is better in terms of efficiency if the fabric is in contact with either the ground side or the anode side, but the surface that is in contact with the fabric (for example, the ground side electrode) It has been found that if unevenness or wrinkles occur between the electrode and the ground electrode, the effect of plasma irradiation, such as etching, radical generation, crosslinking, etc., will be insufficient in areas that are floating and away from the earth side electrode. The quickest way to solve this problem is to increase the feeding tension and winding tension of the fabric. However, even though it is called low-temperature plasma, if it is not cooled, the temperature rises to nearly 200 degrees Celsius, and even if it is cooled, when the tension is increased, the fabric begins to harden all at once, which became a problem in commercialization. The present inventors have conducted extensive research on methods to prevent fabrics from floating or wrinkling, and have arrived at the present invention. First, the fabric should not be rolled with wrinkles or folds, which is natural based on common sense. In order to process the fabric continuously, the innermost layer of the roll has a waste winding for guiding fabric that is at least as long as the machine passing length.
It is necessary to hold the paper by at least 1.3 times, and the edges must not be wrinkled or bent. When sewing the guide fabric and the fabric, overlock is used to avoid folding as much as possible, and if it is unavoidable to use interlock or loop stitching, it is preferable to insert wrinkle-preventing paper or the like. When fabrics are processed continuously, each splicing method is almost the same. In short, the thickness of the fabric at the joint should be as close to the same as possible, or at least less than three times the thickness, otherwise it would be difficult to pass through the seal roll for continuous processing using the air-to-air method. was found to be blocked. In order to spread the fabric prepared in this way, it is not enough to simply apply tension;
110cm, and as the width increases from 110cm to 155cm, there is a difference in distortion between the center and both ends, which causes waving at both ends and wrinkling at the center during long processing times. This often cannot be resolved even by applying tension, and stretching in the horizontal direction can help prevent this. Installation of bend bars and bend rolls, and ear spreading devices such as screw extender rolls were effective. When a rolled fabric is fed out, it has an initial weight, but it becomes lighter in the latter half, which causes a difference in tensile resistance, so it must be kept under a constant tension.
Moreover, the spreading device will not be effective unless a considerable tension load is applied. From such a connection point, after applying a constant tension to the brake, a speed regulating roller is installed that detects the tension using a dancer roll or a tension sensor and feeds it back to change the feed rate.
As a result of adjusting it to between g/in and 500 g/in, it was possible to prevent uneven processing due to lifting from the electrode surface during plasma irradiation treatment, texture hardening, etc., and it became possible to perform stable plasma processing. When the tension is less than 10 g/in, it is not so great for stretchy fabrics, but for fabrics with little stretch, the tension easily reaches zero (0) or sag with small fluctuations, causing horizontal ridge-like irregularities. It may cause uniform processing and is unstable. In addition, when the tension is 500 g/in or more, instability due to floating from the electrode surface disappears, but if the fabric is subjected to discharge treatment under such tension changes, it tends to harden, and there are factors that can be prevented by extreme cooling, and the cost of refrigerant. However, it was important not to exceed 500 g/in in order to cool the fabric to near room temperature and not make it hard. Even with a spreading device, meandering may occur due to differences in thickness and winding distortion of the fabric, and this can be adjusted by actively adding a device that adjusts the meandering of one edge. When the fabric is a highly hygroscopic material, an unexpected problem arose with this tension management. This was particularly noticeable when preparing batch-type roll-wound fabrics, which was unexpected for ordinary films with extremely low moisture absorption. That is, the environment in which the fabric is subjected to plasma discharge treatment is under a reduced pressure of 0.05 Torr to 10 Torr, and is in fact in a state of vacuum drying. Wool, which is highly hygroscopic, exhibits a shrinkage called hygral expansion, and nylon, vinylon, etc. also exhibit dimensional changes. This waits within the batch during the discharge treatment, and inevitably results in a strain difference between the ends of the roller roll, where drying has progressed, and the center, where dryness has progressed, resulting in wrinkles. To prevent this, one method is to stop the roll winding, shake off the cloth, and feed it with a continuous sheet, thereby increasing the density of the cloth so as not to make any difference in the drying state. Shake-off accumulating sheets can be used to connect tails, so they are effective in continuous air-to-air systems, but in batch systems, the amount of preparation becomes too small, which is actually disadvantageous as it increases costs. Another way to prevent this problem is to roll the fabric in an overly dry state and store it in a low-humidity environment to avoid adsorption of moisture as much as possible. An over-dry state means a state where the regain is about half or less than the standard state. More preferably, good results were obtained when the regain was 3% or less and the difference between the inner and outer layers of the roll and the difference at the center end were ±0.5% or less. These requirements have made it possible to perform continuous, uniform and stable plasma processing for long periods of time. The problem of moisture absorption arising from the thus wound rolls exiting the vacuum drying chamber to the outside air arose again. A wound product that has been uniformly processed during low-temperature plasma discharge will elongate due to moisture absorption, resulting in waves due to the difference between the inner and outer layers, and the difference between the center and both ends, degrading the quality of the product. For this reason, in the case of continuous processing using the air-to-air method, after being exposed to the air and before being wound up, in the case of the batch method, the material is once rolled into a roll and is unwound and re-wound to create water vapor. It is important that there is no difference in the moisture content between the inner and outer layers, or between the center and both ends, while the rolls are being brought into contact with each other, and that there is no difference in the moisture content between the inner and outer layers, or between the center and both ends. Ta. In this way, following low-temperature plasma discharge, whether it is continuous processing or batch processing, after the fabric is exposed to the atmosphere,
Bringing steam containing at least water molecules into contact has also achieved remarkable results in preventing radical traps. When a fabric is irradiated with plasma, its surface is activated by high-energy particles and has active sites capable of radical polymerization. Argon,
Helium, nitrogen, carbon monoxide, etc. are used as the activating gas, and especially oxygen and a mixed gas containing oxygen have a long lifespan, probably because they form peroxide at the active sites, and they cause radical polymerization to the fabric in the atmosphere. Although it is convenient for imparting dyes, when it is rolled up and stored for a long period of time, the trapped radicals may cause unnecessary changes beyond the changes caused by surface modification, such as deterioration of the fastness of dyed products. In some cases, it has been found that the material causes color changes and progresses in surface deterioration. These damages could be wiped out by contacting the material with steam containing at least water molecules for humidity conditioning after it exited the atmosphere after plasma irradiation. Synthetic fibers constituting the fabric referred to in the present invention include fibers such as polyester, aramid, polyvinyl alcohol, EVAL, polyamide, polyacrylonitrile, polyurethane, and viscose, and of course, non-hygroscopic fibers other than these may also be included. good. Fabrics include woven fabrics, knitted fabrics, nonwoven fabrics, and composite coated products of these fabrics.Furthermore, in the present invention, in order to further enhance the effect of plasma irradiation on the surface of these fabrics, fine particles, especially silica, are attached to fabrics and Suitable for plasma processing of fabrics coated with resin processing agents. This is because fine particles, especially silica, are greatly affected by adsorbed water, and resin finishing agents are also strongly affected by tension. The plasma irradiation of the present invention refers to low-temperature plasma using a normal method, that is, discharge under reduced pressure below atmospheric pressure, but in order to effectively achieve the present invention, discharge treatment is performed under a pressure of 0.05 Torr to 10 Torr. In this case, the treatment is preferably carried out in an atmosphere of air, nitrogen, nitrogen dioxide, hydrogen, argon, helium, oxygen, carbon monoxide, carbon fluoride, ammonia, carbon chloride, or a mixed gas thereof. The surface of the base material subjected to such plasma irradiation is activated, and the formation of a thin film by etching, crosslinking, or radical polymerization proceeds to achieve surface modification. Example 1 A palace fabric made of polyester filament yarn of 50 denier 36 filaments in the vertical direction and 75 denier 36 filaments in the horizontal direction was made by a conventional washer.
After heat-setting and alkali weight reduction processing, the fabric is dyed black, and silica with an average primary particle size of 15 mμ is added to the dyeing bath and washing bath to adhere 0.1% by weight of silica to the fabric, and then dried to an over-dry state. did. Then, using an internal electrode type batch continuous plasma irradiation device as shown in Figure 1, the frequency was
110KHz, introduced gas oxygen, irradiation energy amount
Plasma irradiation was performed at a rate of 0.24 KWh/m ² and an irradiation zone residence time of 60 seconds. The fabric used had sag at the selvage due to the andon-wound yarn during washer processing, and sagging at both selvages because it was processed with sufficient overfeed during heat setting and finishing setting to give it a texture with good drapability. The texture, darkening effect, and uniformity of plasma irradiation were investigated by changing the running tension on this fabric. At this time, the electrode temperature was set at 45°C and cooled. Color intensity was measured using a self-recording spectrophotometer manufactured by Hitachi. The concentration of dyeing is
It is indicated by the L ^* a ^* b ^* system display L ^* ab value, and the smaller the value, the greater the darkening effect. In this example, fine irregularities were formed by plasma etching to produce a color deepening effect, and since the uniformity of plasma irradiation is seen as a color difference, it is important to evaluate the uniformity. The color depth before plasma irradiation was L ^* ab=19.1.

[Table] When the running tension was 5 g/in, it became defective because it tended to meander, the feed was unstable, and there was a color difference between the center part and the ear part. On the other hand, under a tension of 600 g/in, the running was stable and there was little difference between the center part and the ear part, but it became too hard and was considered defective. On the other hand, those within the scope of the present invention were plasma processed with good runnability and good appearance and texture. When water vapor was applied to the surface of the fabric after plasma processing, a dyed fabric was obtained that did not cause dye fading even after being left for a long time. Example 2 Using the same equipment as in Example 1, 2/2 twill fabrics using 48 count wool double yarn and 48 count polyester double yarn were dyed sky blue. Each double width was 50 yards and 10 squares (460 m) ), white polyester taffeta, nylon taffeta each 44 inches wide 50 m
A total of 4 points of 20 meters (1000 meters) were plasma processed.
The pressure inside the plasma generator was reduced to 10 ^-3 Torr, while the pressure in the roll cloth supply chamber was reduced to 1 Torr, and the atmospheric partial pressure was adjusted to 0.07 Torr and the trimethylchlorosilane partial pressure was adjusted to 0.1 Torr and maintained at 110 KHz, 0.18 KWh/m ² High-frequency power was applied to generate low-temperature plasma, and the cloth was retained for 1 minute and then wound up. After winding, half of each roll of cloth taken out into the atmosphere was rolled back and exposed to steam, but the remaining half was wrapped and sealed with a polyethylene film and left in a warehouse. Polyester had a short time to reach a certain degree of vacuum, about 6 degrees, but wool, nylon,
Especially with wool, it takes more than 30 minutes to reach 1 Torr.
However, the degree of vacuum changed between the beginning of plasma irradiation and the second half of plasma irradiation, which corresponds to the inner layer of the roll, and the gas flow rate had to be changed. After this, when I tested the wool again, I thoroughly dried it to reduce the moisture content to 3% or less, and this problem disappeared. On the other hand, during processing of nylon taffeta, the ears became tense and the center part became loose and wavy, which was resolved by applying a cloth running tension of 15 g/in or more, but it was also over-dried by pre-drying. By performing plasma treatment after that, we were able to eliminate the problem more completely. Although this phenomenon was less common with polyester, the effect of overdrying was observed. After one month, a total of 8 pieces of cloth, one to which water vapor was applied and one to which it was not applied, were taken out and the difference in color was evaluated with the naked eye. Although it cannot be said that the polyester fabric was remarkable, the effect of steam treatment was obtained to some extent. Also, in the case of wool cloth, the sky blue of the wool 2/2 twi that was not exposed to steam became a slightly yellowish sky blue, and in the case of nylon cloth, the nylon taffeta that was not exposed to steam was more yellowish. In contrast, the cloth exposed to steam did not have a yellowish tinge. As for the triboelectrification characteristics of these cloths, no significant difference was observed between the 8 points at a charging voltage of 500 V or less using a rotary static tester.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an apparatus for carrying out the invention. 1, 2, 3...exhaust pipe, 4, 5
...Activation gas and monomer introduction pipe, 6... Unwinding chamber, 7... Plasma discharge chamber, 8... Winding chamber, 9...
... High frequency power supply, 10 ... Polymer sheet-like material, 11
...Unwinding roll, 12... Winding roll, 13,1
4... Cloth tension detection unit, 15, 16... Cloth spreading, ear adjustment device, 21... Rod-shaped high voltage side electrode, 22... Plate-shaped ground side electrode, 23, 24... Seal mechanism.

Claims (1)

[Claims] 1. In a method of low-temperature plasma processing in which a fabric made of synthetic fiber is continuously run between the high-voltage side electrode and the grounded electrode in a zone maintained under reduced pressure, the fabric is Use a material whose moisture content is less than half of the equilibrium moisture content under standard conditions, and whose spreading tension is 10 g/in.
As described above, the fabric was adjusted to 500 g/in or less, and the fabric was plasma-treated while being in close contact with one electrode surface without floating unevenly, and after the plasma treatment, the fabric was exposed to the atmosphere at least A plasma processing method for fabric, characterized by bringing it into contact with steam containing water molecules to perform radical annihilation and humidity conditioning.