KR910008303B1 - Graft copolymerization process for the synthetic fiber - Google Patents

Abstract

A graft copolymerization of a synthetic fiber is characterized by treating the fiber under the low temp. plasma condition of an inert gas controlled to the secondary transition temp. of the fiber, and introducing a vapor phase monomer soln. into the treated fiber by the high vacuum pump. The low temp. plasma is formed by introducing an inert gas into the system of 10-6-1 torr vacuum degree, and glow discharging it by the (in)direct current power or the microwave power. The monomer is pref. (meta)acrylic acid, arylamine, a arylacohol, 2- vinylpyridine, 4-vinylpyridine and/or acrylonitrile.

Description

Graft Copolymerization of Synthetic Fibers

The present invention relates to a graft co-polymerization method of synthetic fibers, and more particularly, graft copolymerization of synthetic fibers by introducing a low-temperature plasma treatment of the synthetic fibers near the secondary transition temperature and introducing a polymerizable monomer into the gas phase. It is about a method.

In general, synthetic fibers have excellent physical properties such as tensile elongation, shape stability, and quick drying, but they also have problems such as hydrophobicity, hygroscopicity, contamination, re-contamination, and static electricity generation. To this end, recent studies have been actively conducted to modify the surface of a high molecular material using a low temperature plasma state formed by a high voltage method of a reactive gas or a non-reactive gas.

For example, Japanese Laid-Open Patent Publication No. 60-162824 discloses a method for treating polyester-based synthetic fibers in a low temperature plasma formed by a mixed gas containing oxygen, an organohalogen compound, and a ketone compound. Patent Publication No. 59-223363 discloses a method for treating cellulose based fiber products in a low temperature plasma formed by oxygen or oxygen-containing mixed gas. However, these conventional techniques are simply a method of using a gaseous low-temperature plasma, the physical effect of forming fine irregularities on the fiber surface by the etching effect of the low-temperature plasma and formed on the surface of the fiber to be treated by the low-temperature plasma treatment The surface modification method using a functional group such as a carboxyl group will be referred to as bar, the product produced by this method has a problem such as deterioration of the performance over time, such as deterioration of physical properties.

On the other hand, as a method for introducing a hydrophilic material into the surface layer of the fiber material, for example, Japanese Patent Laid-Open No. 59-47476 treats polyester fibers in a gaseous low-temperature plasma containing oxygen, and the fibers have a molecular weight of 300 to 2,000. Phosphorus polyalkylene glycol is added 2 to 10% by weight, and then a method of treating with low-temperature plasma such as air, nitrogen, oxygen, argon, etc. has been described. However, this method is a wet process by immersion and is used as wastewater of a monomer solution. Due to the pollution problem occurs, polyalkylene glycol is attached to the surface of the fiber to be treated is nonuniform, there is a problem that the durability is poor because there are a lot of simple physical attachment parts other than graft copolymerization.

In addition to the above, as a further improved method, Korean Patent Application No. 86-6999 (same as the applicant of the present applicant) describes a method of performing graft co-polymerization by introducing a unsaturated monomer into a gas phase after low-temperature plasma treatment of a polymer material. Although graft co-polymerization is performed in this way, good results are recognized in that an effect of forming a relatively functional thin film on the surface of an object to be treated is recognized. Thin film graft-polymerized on the surface of a synthetic fiber material such as polyester, polyamide, polyacrylonitrile, polyethylene, polypropylene, etc. as a garment material, interior material, or other industrial material It must be at least 1μ thick to fully exhibit its function. It turns so there is room for improvement.

Accordingly, the present invention treats the synthetic fibers near the secondary transition temperature and introduces and sprays the monomer solution in the gas phase at a temperature at which thermal polymerization is impossible, thereby forming a uniform graft copolymer layer having excellent functionality and having a thickness of 1 μ or more, thereby improving the surface of the polymer material. It is an object of the present invention to provide a graft copolymerization method of synthetic fibers that can be excellently modified.

Hereinafter, the present invention will be described in detail.

In the present invention, when graft copolymerization is carried out by introducing a gaseous monomer into a low-temperature plasma-treated synthetic fiber, first, the synthetic fiber is treated in a low-temperature plasma of an inert gas adjusted to near the secondary transition temperature of the synthetic fiber. It is a graft polymerization method of a synthetic fiber, characterized in that the polymer monomer solution is introduced into the fiber, but the polymerizable monomer solution is heated to a temperature range where thermal polymerization does not occur with a high vacuum pump.

Hereinafter, the present invention will be described in more detail.

The present invention will first be treated is water to form a chemically active radicals in the surface layer of the synthetic fibers, there is to process the synthetic fibers at a low temperature plasma of an inert gas, a vacuum degree of 10 ^-6 to 1 in order to form a low temperature plasma In the same Torr An inert gas such as helium, neon, argon krypton, xenon, or nitrogen gas is introduced into the system, followed by a glow discharge using an AC or DC power source having a frequency of 60 Hz or a microwave power source having a known frequency of 13.56 MHz or less. You can create a glow Disoharge.

In this case, the discharge type may be a general electrode discharge, that is, a system internal electrode type or an external type electrode type using metal plate electrodes such as copper, nickel, and platinum, and an induction coil type using a high frequency wave, a waveguide type using a microwave, and the like. The electrodeless discharge type may be used.

In performing such a discharge, a high-voltage discharge with a high frequency typically has a high-density low-temperature plasma state, extends the life of the generated chemically active radicals, and freely adjusts the size of the system. Known.

Subsequently, the object to be treated is treated in the low-temperature plasma state of the inert gas formed as described above. In the present invention, the synthetic fiber is introduced into the plasma state near the secondary transition temperature (Tg) of the treated fiber. In general, polymer materials do not change their internal energy or entropy near the secondary transition temperature, but their physical properties such as specific heat, expansion rate, and compression rate not only change rapidly, but also their specific volume starts to change rapidly. It is known that this is because the movement of molecules is relaxed. Thus, in the present invention, by performing a low temperature plasma treatment in a state in which the material of the synthetic fiber is maintained at the secondary transition temperature, a very excellent treatment effect of enhancing affinity with the monomer, which is the next process, can be obtained.

On the other hand, the method of controlling the processing temperature of the synthetic fibers in the vicinity of the secondary transition temperature is possible through power control such as high frequency or microwave, distance control between electrodes, vacuum degree control, etc. The temperature of the relay may be adjusted so that the synthetic fiber can be processed near the secondary transition point by using an electrically insulating medium.

Looking out the secondary transition temperature of an exemplary composite fiber, polyethylene terephthalate fiber is known to be 342 ^o and K near the nylon 66 fiber is 330 ^o K polyethylene fibers are near 148 K ^o. Therefore, when the above-mentioned synthetic fibers are treated in a low temperature plasma state under the same conditions, it can be seen that the graft efficiency of the polymerizable monomer increases in the order of polyethylene, nylon 66, polyethylene terephthalate. This proves that the secondary transition temperature acts as one factor that greatly affects the efficiency of the polymerizable monomer graft polymerization.

Cold plasma treated synthetic fibers near the secondary transition point are treated with a polymerizable monomer introduced into the gas phase in a high vacuum state. In this case, the polymerizable monomer should have a vapor pressure of 17.535 mmHg or less at a temperature of 20 ° C., and if the vapor pressure at 20 ° C. is used at 17.535 mmHg or more, gas phase introduction becomes difficult. In particular, in order to maintain the maximum amount of the polymerizable monomer introduced into the gas phase in the high vacuum system to the maximum, the polymerizable monomer is heated to a temperature range where thermal polymerization does not occur, and then the monomer is introduced into the system in the vapor phase using a high vacuum pump. Spray to ensure sufficient diffusion.

As described above, the monomer gas phase injection method of the present invention requires a technical operation that must be appropriately operated according to the type of monomer. When the temperature is increased to 20 mmHg, the vapor pressure increases, so that acrylic acid is sufficiently introduced in a closed system having an initial vacuum of 10 ^-2 Torr, thereby forming a graft copolymer layer of 1 μ or more. Polymerizable monomers according to the present invention include, but are not limited to acrylic acid, methacrylic acid, arylamine, aryl alcohol, 2-vinylpyridine, 4-vinylpyridine, acrylonitrile, and the like, and monomers having a relatively low boiling point under normal pressure. May be used alone or in combination.

On the other hand, as a method of treating the monomer to the object to be treated, there is a solution phase dipping method or a solution phase spraying method in addition to the gas phase introduction method, but these methods solve the problems of equipment development, difficulty in maintaining the degree of vacuum in the treatment chamber, stability, etc. The problem remains.

When the graft copolymerization method of the synthetic fiber according to the present invention is carried out in this way, since the polymerizable monomer is supplied to the gas phase, the utilization efficiency of the monomer is high, and the amount of the by-product homopolymer is minimal, so the graft copolymer polymerization rate Not only is this high, but the graft having a thickness of 1 μm or more on the surface layer of synthetic fibers ??? Since it is possible to form a functional thin film, it is possible to impart permanent functionality, such as hydrophilicity, antistatic property, deep colorability, dye resistance, antifouling property, biocompatibility, antibacterial deodorization, etc. according to the type of monomer to be selected. In addition, compared to the conventional wet treatment method, there is an advantage of excellent work stability and reproducibility, pollution-free and simple installation.

The present invention will be described in detail based on Examples and Comparative Examples.

[Examples 1 to 6]

Next, a low-temperature plasma of an inert gas was formed according to the conditions shown in Table 1, followed by treatment of the polyester fibers (Examples 1 to 3) and nylon 6 fibers (Examples 4 to 6), which were to be treated, Was graft copolymerized with acrylic acid according to the monomer introduction conditions.

[Comparative Example 1 to Comparative Example 6]

Following the conditions shown in Table 2 to form a low-temperature plasma of the inert gas, and treated with the polyester fibers (Comparative Examples 1 to 3) and nylon 6 fibers (Comparative Examples 4 to 6) to be treated, and then treated Water was graft copolymerized with acrylic acid according to the monomer introduction conditions.

TABLE 1

TABLE 2

The physical properties of the synthetic fibers graft copolymerized according to Examples 1 to 6 and Comparative Examples 1 to 6 are shown in Tables 3 and 4 below.

In evaluating the physical properties of the sample, first, the state of the cross section and the surface of the graft copolymer layer was observed using a transmission electron microscope, and the average thickness was measured. After quantifying the trace amount of grafted acrylic acid by atomic absorption spectrometer, the sample before and after the graft was treated with 1% aqueous sodium carbonate solution at 80 ° C. for 1 hour to replace the carboxyl group with sodium salt, followed by distilled water and ethyl alcohol. The sodium content is quantitatively measured.

TABLE 3

TABLE 4

Claims (1)

In the graft copolymerization by introducing a gaseous monomer into a low temperature plasma-treated synthetic fiber, the synthetic fiber is treated in a low-temperature plasma of an inert gas controlled near the secondary transition temperature of the synthetic fiber, and then the gas phase polymerization is carried out. A graft copolymerization method of synthetic fibers, characterized in that the introduction of the monomer, but injecting the monomer in the solution state heated to a temperature range where thermal polymerization will not occur by spraying with a high vacuum pump.