JP2022132768A - Water-repellent fiber and water-repellent fiber structure and method for producing the same - Google Patents

Abstract

To provide a water-repellent fiber and a water-repellent fiber structure that can be used for a long time even under high radiation and has excellent water repellency and radiation resistance, and a method for producing the same.SOLUTION: The present invention discloses a water-repellent fiber and a water-repellent fiber structure in which: at least one fiber selected from plasma-treated or electron beam-irradiated wholly aromatic polyamide fiber, poly p-phenylenebenzobisoxazole fiber and wholly aromatic polyester fiber or a fiber structure composed of the fiber is treated and covered with phenylmethyl silicone or phenyl-modified silicone. A method for producing a water-repellent fiber or a water-repellent fiber structure includes a first step for subjecting the fiber or a fiber structure composed of the fiber to plasma treatment or electron beam irradiation and a second step for covering the surface of the treated fiber or fiber structure with phenylmethyl silicone or phenyl-modified silicone.SELECTED DRAWING: None

Description

INDUSTRIAL APPLICABILITY The present invention can be used, for example, in radiation environments such as nuclear power plants, spent nuclear fuel reprocessing facilities, nuclear related facilities such as proton accelerators, medical sites where radiation therapy is performed, and other industrial and medical radiation inspection machines. It relates to a water-repellent fiber and a water-repellent fiber structure that can be made, and a method for producing the same.

Immediately after the tsunami that occurred in March 2011, Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station experienced a so-called meltdown, in which the nuclear fuel melted down, and countermeasures are being taken. In decommissioning, it is necessary to take out the melted nuclear fuel from the reactor containment vessel. The work of removing nuclear fuel and fuel debris from the reactor building is carried out in a highly radioactive environment, and the fuel debris is located at the bottom of the reactor containment vessel and is covered with cooling water. It is necessary to select and configure a material that is excellent in radiation resistance and water resistance.

In particular, metal materials with excellent radiation resistance are mainly used for the materials of robots that perform debris retrieval work, but organic fibers are sometimes used from the viewpoint of flexibility and weight reduction. As organic fibers, natural fibers (eg, cotton, hemp, etc.) and synthetic fibers (eg, polyester, polyamide, polyvinyl alcohol fibers, etc.) are generally used. However, these natural fibers and synthetic fibers are known to have poor radiation resistance under high radiation. Organic fibers having excellent radiation resistance include, for example, wholly aromatic polyamide fibers, polyparaphenylene benzobisoxazole fibers, and wholly aromatic polyester fibers. These organic fibers are so-called wholly aromatic high-strength fibers, and have radiation resistance several times or more that of other organic fibers.

However, the surfaces of these fibers are not water-repellent, and radioactive materials adhere to the surfaces of the fibers or the surfaces of cords and fabrics made of fibers during debris retrieval work in water containing radioactive materials. You can expect it to happen. Debris retrieval robots must be thoroughly decontaminated in the reactor containment vessel by washing with water, etc. before being removed from the reactor, but it is difficult to completely remove the radioactive materials adhering to the fiber surfaces. Therefore, the water repellency of the fiber surface is very important from the viewpoint of removing radioactive substances.

In Patent Document 1, a fiber structure containing organic fibers such as polyester fiber, polyamide fiber and cellulose fiber is immersed in a treatment bath containing a treatment liquid containing a water repellent agent, and the water repellent agent is exhausted to repel it. Methods for water processing have been proposed. However, these organic fibers are known to have poor radiation resistance. As water repellents, polydimethylsiloxane, methylhydrogenpolysiloxane, and amino-modified silicone have been proposed. not suitable for use. In addition, although fluorine-based compounds are excellent in water repellency, they are not suitable for use in nuclear power plants because there is a concern that halogens may cause stress corrosion of metal materials such as stainless steel.

Patent Literature 2 proposes a production method in which para-type wholly aromatic polyamide fibers having anhydrous aluminum silicate and/or sodium aluminosilicate adhered to the surface thereof are plasma-treated to improve adhesiveness. However, no mention is made of imparting water repellency, and the effect cannot be expected.

Patent Document 3 also proposes a similar technique. That is, high-strength fibers that do not contain an oil agent are opened as necessary to form a filament bundle on a flat plate, and while the filament bundle on the flat plate is run at 3 to 30 m / min, the surface is covered with an uneven A method for producing surface-hydrophilized high-strength fibers has been proposed, characterized in that atmospheric pressure plasma treatment is performed under active gas conditions at a frequency of 3 to 26 Hz. However, no mention is made of the improvement of water repellency, and the effect cannot be expected.

Patent Document 4 describes a method for producing phenylmethyl silicone, which is a silicone release composition. However, there is no mention of radiation resistance or fibers to which it is imparted.

Non-Patent Document 1 proposes preparation of PET fibers having high durability and water repellency by grafting a fluorine-based polymer onto a polyester plain woven fabric by electron beam irradiation. However, like Patent Document 1, it is not suitable for use under high radiation because it is inferior in radiation resistance.

Japanese Patent No. 4667935 JP 2006-37297 A JP 2011-58117 A JP-A-57-207646

Textile Society Journal (Textile and Industry), Vol.64, No.8 (2008), Textile Processing by Electron Beam Irradiation Technology

In view of the background of such prior art, the present invention can be used as a member of a robot necessary for debris removal from the nuclear reactor containment vessel of the Tokyo Electric Power Company Fukushima Daiichi Nuclear Power Station, and can be used for a long period of time even under high radiation. An object of the present invention is to provide usable water-repellent fibers and water-repellent fiber structures excellent in water repellency and radiation resistance, and a method for producing the same.

In order to solve the above problems, the present inventors have made intensive studies and found that organic fibers with excellent radiation resistance, such as wholly aromatic polyamide fibers, polyparaphenylenebenzbisoxazole fibers and wholly aromatic polyester fibers, are selected. At least one type of fiber or a fiber structure made of the fiber is subjected to plasma treatment or electron beam irradiation treatment, and then phenylmethyl silicone or phenyl-modified silicone is applied to the fiber surface or the fiber structure surface. The present inventors have found that these problems can be solved at once, and have completed the present invention.

That is, the present invention is as follows.
(1) At least one fiber selected from wholly aromatic polyamide fiber, polyparaphenylenebenzbisoxazole fiber and wholly aromatic polyester fiber, or a fiber structure comprising the fiber, which has been subjected to plasma treatment or electron beam irradiation treatment A water-repellent fiber or a water-repellent fiber structure, characterized in that phenylmethylsilicone or phenyl-modified silicone is adhered to said water-repellent fiber.
(2) The water-repellent fiber or water-repellent fiber structure according to (1) above, wherein the phenyl group content of the phenylmethyl silicone or phenyl-modified silicone is 10 mol % or more and 50 mol % or less.
(3) The water-repellent fiber according to (1) or (2) above, wherein the amount of phenylmethyl silicone or phenyl-modified silicone attached is 1% by weight or more and 15% by weight or less with respect to the weight of the fiber or fiber structure. Or a water-repellent fiber structure.
(4) The water-repellent fiber or water-repellent fiber structure according to any one of (1) to (3) above, wherein the water repellency change rate determined by formula (I) is 100% or more.
Water repellency change rate (%)=[θ2/θ1]×100 (I)
θ1: contact angle of fiber or fiber structure before irradiation
θ2: contact angle of the fiber or fiber structure after irradiation (5) The water-repellent fiber or water-repellent fiber structure according to any one of (1) to (4), wherein the fiber is a wholly aromatic polyamide fiber. .
(6) A radiation-resistant material using the water-repellent fiber or water-repellent fiber structure according to any one of (1) to (5).
(7) At least one fiber selected from wholly aromatic polyamide fiber, polyparaphenylenebenzbisoxazole fiber and wholly aromatic polyester fiber, or a fiber structure made of the fiber, is subjected to plasma treatment or electron beam irradiation treatment. a first step;
and a second step of applying phenylmethylsilicone or phenyl-modified silicone to the treated surface of the fiber or fiber structure.

The water-repellent fiber and water-repellent fiber structure of the present invention are a fiber material that is resistant to deterioration even in a highly radioactive environment, in water or in a high-humidity environment, can be used for a long period of time, and has a long life. In particular, it is suitable as a member of a robot for removing debris in the decommissioning work of a nuclear power plant.

It is a figure which shows the outline of the evaluation apparatus of water-repellent-agent fall-off property.

The water-repellent fiber and water-repellent fiber structure excellent in radiation resistance of the present invention, and the method for producing the same will be described in detail.

In the water-repellent fiber and water-repellent fiber structure of the present invention, phenylmethylsilicone or phenyl-modified silicone is attached to high-strength fiber or a high-strength fiber structure made of the fiber that has been subjected to plasma treatment or electron beam irradiation treatment. It is characterized by being made.

[High-strength fiber]
The present invention uses organic fibers, so-called wholly aromatic high-strength fibers. The wholly aromatic high-strength fibers include wholly aromatic polyamide fibers, polyparaphenylenebenzobisoxazole fibers, and wholly aromatic polyester fibers, and at least one selected from these wholly aromatic high-strength fibers. of fibers are used. These fibers have advantages such as a high tensile modulus, flexibility, heat resistance, a high limiting oxygen index (LOI) value, and resistance to burning, as well as excellent radiation resistance. In particular, its radiation resistance is several times higher than that of other organic fibers. Among them, it is preferable to use a wholly aromatic polyamide fiber because of its excellent strength characteristics. A commercially available product may be used as the wholly aromatic high-strength fiber.
In the following description, the wholly aromatic high-strength fiber is referred to as "high-strength fiber", and the wholly aromatic high-strength fiber structure made of the fiber is referred to as "high-strength fiber structure". Also, high-strength fibers and high-strength fiber structures may be collectively referred to as "high-strength fibers and the like".

The wholly aromatic polyamide fiber is generally a fiber having at least one optionally substituted divalent aromatic group, and is not particularly limited as long as it is a fiber having at least one amide bond. It may be a well-known one called In the above, "optionally substituted divalent aromatic group" means a divalent aromatic group optionally having one or more identical or different substituents.

Wholly aromatic polyamide fibers are also called aramid fibers. Aramid fibers can be broadly classified into para-aramid fibers and meta-aramid fibers.
Examples of para-aramid fibers include polyparaphenylene terephthalamide fibers (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark), etc.), copolyparaphenylene-3,4'-oxydiphenylene terephthalamide fibers (Teijin manufactured by Co., Ltd., trade name "Technora" (registered trademark), etc.).
Examples of meta-aramid fibers include polymetaphenylene isophthalamide fibers (manufactured by DuPont, trade name "Nomex"), Teijin Ltd., trade name "Conex"), and the like.
Among them, para-aramid fibers are preferred, and poly-paraphenylene terephthalamide fibers are more preferred, because of their excellent tensile strength.

Examples of polyparabenzobisoxazole fibers include those manufactured by Toyobo Co., Ltd. under the trade name of "Zylon", and examples of wholly aromatic polyester fibers include those manufactured by Kuraray Co., Ltd. under the trade name of "Vectran".

The high-strength fibers of the present invention are used in the form of fibers or fiber structures composed of the fibers.
Forms of high-strength fibers include filaments or bundles of filaments, staple fibers, and the like.
Forms of high-strength fiber structures include woven fabrics, knitted fabrics, knitted fabrics, honeycomb-like fabrics, non-woven fabrics, cords, ropes, nets, and the like.

The fineness of the high-strength fibers should be thick from the viewpoint of strength, but if the fineness is too thick, the processability into a fiber structure is inferior. From an economical point of view, it is preferably 110 dtex or more, more preferably 110 dtex to 6400 dtex, still more preferably 420 dtex to 3300 dtex.

The basis weight of the high-strength fiber structure is preferably 50 g/m ² to 1000 g/m ² . When aramid fibers are used, even if the basis weight is 50 g/m ² , the tensile strength of the fiber structure can be sufficiently maintained, thereby making it possible to produce a lightweight and high-strength fiber structure. Therefore, it is particularly suitable. In addition, if the basis weight is 1000 g/m ² or less, a fiber structure having no problem in terms of lightness and bending fatigue resistance can be obtained. The basis weight of the high-strength fiber structure is more preferably 75 g/m ² to 700 g/m ² , still more preferably 100 g/m ² to 500 g/m 2 from the viewpoint of the balance between tensile strength, lightness, and bending fatigue resistance. ^m2 .

[surface treatment]
In the present invention, plasma treatment or electron beam irradiation treatment is performed in order to improve the adhesiveness of the surface of high-strength fibers, etc., prior to water repellent imparting treatment (first step).
Here, water repellency can be imparted temporarily to the high-strength fiber or the like of the present invention by applying a water repellent, which will be described later, without surface treatment. However, in this method, the adhesion between the water repellent agent and the fiber surface is poor, and when the fiber surface is rubbed, the water repellent agent falls off, impairing the water repellent effect. Therefore, in order to improve the adhesion between the water repellent agent and the fiber, a method of etching by applying acid or alkali to the fiber surface is sometimes used, but this method affects not only the fiber surface but also the inside of the fiber. cannot be denied, and is known to result in a decrease in fiber strength.
In the present invention, in order to avoid such a decrease in strength, plasma treatment or electron beam irradiation treatment that affects only the surface layer of the fiber is performed to modify the surface of the high-strength fiber, etc., and the water repellent agent. Adhesion can be significantly improved. Plasma treatment and electron beam irradiation treatment are preferably carried out while conveying the fiber or fiber structure from the point of view of treatment efficiency and reduction of treatment unevenness on the surface layer of the fiber.

As the plasma treatment, a conventionally known treatment may be employed, and examples thereof include atmospheric pressure plasma treatment (atmospheric pressure plasma treatment) and low pressure plasma treatment (vacuum plasma treatment). Plasma irradiation equipment used for plasma treatment includes high-frequency induction method, capacitively coupled electrode method, corona discharge electrode-plasma jet method, parallel plate type, remote plasma type, normal pressure plasma type, ICP type high density plasma type, etc. is mentioned. These processing methods and processing apparatuses are appropriately selected and used. Among these, atmospheric pressure plasma treatment by glow discharge performed at atmospheric pressure or pressure near atmospheric pressure is preferable. By carrying out near atmospheric pressure, there is an advantage that large-scale equipment and complicated operations such as vacuum equipment and vacuum operation are not required. Normal pressure or a pressure close to atmospheric pressure means 1.333×10 ⁴ to 10.664×10 ⁴ Pa, which is easy to adjust and can be discharged with a simple device of 9.331×10 ⁴ to 10 Pa. 0.397×10 ⁴ Pa is preferred.

The plasma processing method includes a direct method and a remote method, but the plasma processing method in the present invention is not particularly limited.
The direct method is a method in which continuous fibers or fiber structures (such as continuous fibers) are placed between parallel plate electrodes for treatment. Since the continuous fiber or the like is directly introduced into the plasma atmosphere, the treatment effect is generally high, and various surface modification conditions can be used.
The remote method is a method in which plasma generated between electrodes is sprayed onto fibers or the like for processing.
Considering damage to fibers, etc., that may be caused by plasma treatment, the remote method is preferable because it causes less damage.

Plasma treatment can impart various functional groups to the surface of fibers and the like. For example, after the nitrogen plasma treatment, the composition ratio of nitrogen is greater than before the treatment. According to XPS (X-ray photo-electron spectroscopy) analysis results, functional groups such as -C-N, -C-O, -C=O, -CON, and -COO are formed on the surface of plasma-treated fibers. It is presumed that

The frequency of plasma treatment is preferably between 3 kHz and 26 kHz. When the frequency exceeds 26 kHz, electrons and ions are accelerated and collide with the fiber surface at high speed, which may break chemical bonds on the surface and reduce the tensile strength of the fiber. On the other hand, if the frequency is less than 3 kHz, acceleration of electrons and ions will be insufficient, resulting in insufficient treatment of the fiber surface.

The plasma irradiation time for plasma treatment is preferably 0.3 seconds to 8 seconds. More preferably 0.4 seconds to 6 seconds, particularly preferably 0.5 seconds to 5 seconds. If the time is 0.3 seconds or longer, the treatment of the fiber surface is not insufficient, and the water repellent agent can be strongly adhered, so there is no fear that the water repellent agent will come off. Moreover, if the time is 8 seconds or less, it is possible to prevent the tensile strength of the high-strength fibers from decreasing due to the plasma treatment, and to prevent the treatment time and cost from increasing, so there is no fear of impairing economic efficiency.

The atmosphere (processing gas) for plasma processing includes gases that generate plasma by applying an electric field, such as air, oxygen, nitrogen, argon, helium, and carbon dioxide, and these are used alone. may be used, or a mixture of two or more may be used. Among them, it is preferable to use nitrogen because plasma treatment can be performed with high power, safety, and the price of the gas alone is low.

[Water repellent]
In the present invention, phenylmethylsilicone or phenyl-modified silicone is applied (second step) to the surface of the fiber or fiber structure that has been subjected to plasma treatment or electron beam irradiation treatment in the first step, thereby imparting water repellency or A water-repellent fibrous structure is manufactured.
Water repellents include hydrocarbon compounds, polydimethylsiloxane, methylhydrogenpolysiloxane, amino-modified silicone, and the like. Not suitable for use in For example, hydrocarbon compounds are said to have radiation resistance problems. Dimethylsilicone-based compounds are generally considered to have poor radiation resistance, but phenylmethylsilicone is said to have superior radiation resistance to other silicones. In addition, although fluorine-based compounds are excellent in water repellency, they are not suitable for use in nuclear power plants because of concerns about stress corrosion of metals such as stainless steel due to halogens in nuclear power plants.

A search for compounds that provide both water repellency and radiation resistance has revealed that phenylmethylsilicone or phenyl-modified silicone are preferred. Phenylmethylsilicone is represented by, for example, chemical formula (1) and chemical formula (2). As phenyl-modified silicone, for example, BESIL (registered trademark) phenyl-modified silicone (manufactured by Shin-Etsu Silicone Co., Ltd.) and the like are known. Phenylmethylsilicone is preferred in the present invention.

The phenyl group content of the phenylmethyl silicone and phenyl-modified silicone is preferably 10 mol % or more and 50 mol % or less, more preferably 15 mol % or more and 40 mol % or less. More preferably, it is 25 mol % or more and 40 mol % or less. If the phenyl group content is within the above range, the water repellency will not decrease even in a high radiation environment.
Phenylmethylsilicone and phenyl-modified silicone are preferably used in the form of straight oils or aqueous emulsions.

The amount of phenylmethyl silicone and phenyl-modified silicone attached is preferably 1% by weight or more and 15% by weight or less of the weight of the fiber or fiber structure. If it is 1% by weight or more, sufficient water repellency can be exhibited. Also, if the amount is 15% by weight or less, there is no fear that the water repellent will fall off from the fiber or fiber structure. The adhesion amount is more preferably 1.5% by weight or more and 13% by weight or less, and still more preferably 2% by weight or more and 12% by weight or less.

Next is the treatment of applying a water repellent agent. The method of applying a water repellent agent is not particularly limited, and any conventionally known method may be employed. A guide method using a pump and the like can be mentioned. Usually, it is applied at a room temperature of about 10 to 40° C., but conditions such as temperature may be appropriately adjusted in order to adjust the adhesion amount.

In the present invention, the high-strength fibers such as aramid fibers that have been subjected to plasma treatment or electron beam irradiation treatment may be treated with a water repellent agent. A water repellent treatment may be performed.

[Water-repellent fiber and water-repellent fiber structure]
The water-repellent fiber and water-repellent fiber structure of the present invention produced by the above method preferably have a water repellency change rate of 100% or more. The water repellency change rate is the change rate of the contact angle between the water-repellent fiber or the water-repellent fiber structure and the pure water when the pure water is dropped on the water-repellent fiber or the water-repellent fiber structure before and after irradiation. The water repellency change rate can be obtained by the following formula (I). The water repellency change rate of the present invention is more preferably 103% or more, still more preferably 105% or more. The higher the water repellency change rate, the better the water repellency after working in a highly radioactive environment, and the easier the removal of contaminated water from the contaminated fiber or fiber structure.
Water repellency change rate (%)=[θ2/θ1]×100 (I)
θ1: contact angle of fiber or fiber structure before irradiation
θ2: Contact angle of fiber or fiber structure after irradiation

The water-repellent fiber and water-repellent fiber structure of the present invention have excellent water repellency, radiation resistance, high strength characteristics, tensile modulus, heat resistance, and flame retardancy. It can be used in a wide range of applications, and is particularly suitable as a member of a robot for removing debris in decommissioning work of a nuclear power plant, a water bag, and the like.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to them. The evaluation methods and measurement methods described in Examples are as follows.

(Evaluation of radiation resistance)
For evaluation of radiation resistance, after irradiating the fiber or fiber structure to which the water repellent was applied, a tensile test was performed on the fiber or fiber structure to compare and evaluate the tensile strength before and after irradiation. Radiation irradiation was carried out at room temperature (in air) with γ-rays (Co60), and the irradiation was completed at a cumulative absorbed dose of 100 kGy. The strength retention rate after irradiation was rated as x when less than 70% of that before irradiation, Δ when 70% or more and less than 95%, and ◯ when 95% or more.

(Method for measuring contact angle)
A portable contact angle meter PG-X manufactured by FIBROsystem AB (Sweden) was used as a measuring device. For the measurement, a measuring device was set on the yarn wound around the sample in an aligned manner, pure water was dropped onto the yarn, and the contact angle between the aligned yarn row and the pure water was detected. A smaller value of the contact angle indicates a more hydrophilic surface, and a larger value indicates a more water-repellent surface. A contact angle of less than 80° was ranked as x, a contact angle of 80° or more and less than 90° was ranked as Δ, and a contact angle of 90° or more was ranked as ○.

(Evaluation of detachability of water repellent agent)
The water-repellent agent-imparted fiber is set in a rewinding machine and rewound under a constant tension. Evaluate using the equipment shown in .
A raw yarn wound on a paper tube is passed through a roller guide and rollers 1 to 3, and is bent at about 90 degrees in a ring guide. After that, it passes through rollers 4 to 7, is tensioned with a tension device of 250 g, passes through roller 8, and is wound up by a winder at a speed of 50 m/min. A tension device is used to adjust the tension between the roller 3 and the ring guide to 250 g.
After 1 minute of rubbing, the weight of scum deposited on the ring guide was measured and ranked as follows.
×: 1.5 mg or more △: 1.0 mg or more and less than 1.5 mg ○: less than 1.0 mg

(Example 1)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name “KEVLAR” (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 1 second while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The water repellent is methylsilicone containing 35 mol % of phenyl groups and is sold as a straight oil. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 10 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 2)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name “KEVLAR” (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 2 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 10 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 3)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name “KEVLAR (registered trademark)”) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 4 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 10 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 4)
A wholly aromatic polyester fiber having a fineness of 1580 dtex (manufactured by Kuraray Co., Ltd., trade name "Vectran" (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 1 second while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 10 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 5)
A wholly aromatic polyester fiber having a fineness of 1580 dtex (manufactured by Kuraray Co., Ltd., trade name "Vectran" (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 2 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 10 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 6)
A wholly aromatic polyester fiber having a fineness of 1580 dtex (manufactured by Kuraray Co., Ltd., trade name "Vectran" (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 4 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 10 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 7)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name “KEVLAR” (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 2 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 1 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 8)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name “KEVLAR” (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 2 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 20 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Example 9)
A wholly aromatic polyamide fiber fabric (KEVLAR (registered trademark) plain fabric, basis weight 220 g/m ² ) was cut into 30 cm squares and plasma-treated.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. The fabric was clamped in the plasma treater and plasma treated for 1 second.
The plasma-treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent is applied to the plasma-treated fabric in the form of a water-based emulsion so that the adhesion amount is 3 w/w%, and hot air drying is performed to adhere the water repellent agent to the fabric surface, resulting in water repellency. A woven fabric (water-repellent fiber structure) was produced.
Radiation resistance (strength retention) and water repellency (contact angle) of the produced water-repellent fabric were evaluated.

(Example 10)
A wholly aromatic polyamide fiber fabric (KEVLAR (registered trademark) plain fabric, basis weight 220 g/m ² ) was cut into 30 cm squares and plasma-treated.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. The fabric was fixed in the plasma treater and plasma treated for 2 seconds.
The plasma-treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent is applied to the plasma-treated fabric in the form of a water-based emulsion so that the adhesion amount is 3 w/w%, and hot air drying is performed to adhere the water repellent agent to the fabric surface, resulting in water repellency. A woven fabric (water-repellent fiber structure) was produced.
Radiation resistance (strong retention rate) and water repellency (contact angle) were evaluated for the produced water-repellent fabric.

(Example 11)
A wholly aromatic polyamide fiber fabric (KEVLAR (registered trademark) plain fabric, basis weight 220 g/m ² ) was cut into 30 cm squares and plasma-treated.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. The fabric was fixed in the plasma treater and plasma treated for 4 seconds.
The plasma-treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above-mentioned water repellent agent is applied to the plasma-treated fabric in the form of a water-based emulsion so that the adhesion amount is 3 w/w%, and hot air drying is performed to adhere the water repellent agent to the fabric surface, resulting in water repellency. A woven fabric (water-repellent fiber structure) was produced.
Radiation resistance (strong retention rate) and water repellency (contact angle) were evaluated for the produced water-repellent fabric.

(Comparative example 1)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name “KEVLAR” (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 2 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. As the water repellent, a 15% diluted solution of a fluorine-based resin emulsion (trade name: M Guard PF-11) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 3 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Comparative example 2)
A wholly aromatic polyamide fiber fabric (KEVLAR (registered trademark) plain fabric, basis weight 220 g/m ² ) was cut into 30 cm squares and plasma-treated.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. The fabric was fixed in the plasma treater and plasma treated for 2 seconds.
The plasma-treated fabric was subsequently subjected to a water repellent application. As the water repellent, a 15% diluted solution of a fluorine-based resin emulsion (trade name: M Guard PF-11) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used. The above water repellent agent is applied to the plasma-treated fabric so that the adhesion amount is 3 w / w%, hot air drying is performed to adhere the water repellent agent to the fabric surface, and the water repellent fabric (water repellent fiber structure) was produced.
Radiation resistance (strong retention rate) and water repellency (contact angle) were evaluated for the produced water-repellent fabric.

(Comparative Example 3)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name “KEVLAR” (registered trademark)) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 2 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. As the water repellent, a 20% dilution of a silicone-based resin emulsion (trade name: M Guard NFC-30) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used. The above-mentioned water repellent agent was applied to the plasma-treated fiber so that the adhesion amount was 4 w/w %, and hot air drying was performed to adhere the water repellent agent to the fiber surface to produce a water repellent fiber.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Comparative Example 4)
A nylon fiber having a fineness of 2150 dtex (manufactured by Toray Industries, Inc., trade name “Promilan”) was wound on a reel for 1000 m and subjected to plasma treatment.
Plasma treatment was performed under atmospheric pressure as follows. The plasma processing chamber was shielded from the outside air, and nitrogen gas was purged into the chamber at a rate of 25 L/min for processing under a nitrogen atmosphere. A tension was applied to the reels on the unwinding side and the reel on the winding side, and plasma treatment was performed for 2 seconds while conveying the fiber. The treated fiber was wound on a 10 cm wide reel.
The plasma treated fabric was subsequently subjected to a water repellent application. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The water repellent is methylsilicone containing 35 mol % of phenyl groups and is sold as a straight oil. The above water repellent agent was applied to the plasma-treated aramid fiber so that the adhesion amount was 10 w / w%, and hot air drying was performed to attach the water repellent agent to the fiber surface to produce a water repellent fiber. .
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Comparative Example 5)
A wholly aromatic polyamide fiber having a fineness of 1670 dtex (manufactured by DuPont-Toray Co., Ltd., trade name "KEVLAR" (registered trademark)) was wound on a reel for 1000 m and applied with a water repellent agent.
A tension was applied to the reels on the unwinding side and the reel on the winding side, and the fibers were transported at a speed of 6 m/min, and the water repellent agent was applied without plasma treatment. The fibers to which the water repellent agent had been applied were wound on a reel with a width of 10 cm. Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above water repellent agent is applied to the aramid fiber that has not been plasma treated so that the adhesion amount is 10 w / w%, and hot air drying is performed to adhere the water repellent agent to the fiber surface, resulting in a water repellent fiber. made.
The prepared water-repellent fibers were evaluated for radiation resistance (strength retention), water repellency (contact angle), and removability of the water-repellent agent.

(Comparative Example 6)
A wholly aromatic polyamide fiber fabric (KEVLAR (registered trademark) plain fabric, basis weight 220 g/m ² ) was cut into 30 cm squares, and a water repellent agent was applied thereto without plasma treatment.
Phenylmethylsilicone oil (trade name: DOWSIL SH710 Fluid) manufactured by Dow Toray Industries, Inc. was used as the water repellent agent. The above water repellent agent is applied to the fabric that has not been plasma treated so that the adhesion amount is 3 w / w % in the state of an aqueous emulsion, and hot air drying is performed to adhere the water repellent agent to the fabric surface. A water-repellent fabric (water-repellent fiber structure) was produced.
Radiation resistance (strength retention) and water repellency (contact angle) of the produced water-repellent fabric were evaluated.

Table 1 shows the processing conditions and the amount of water repellent agent adhered in Examples and Comparative Examples.

Table 2 shows the evaluation results of Examples and Comparative Examples.

From the results in Table 2, it can be seen that the water-repellent fibers and water-repellent fiber structures of the present invention are excellent in strength retention and water repellency after irradiation, and are also excellent in water repellent agent removal properties. Among them, Examples 1-3 and 7 are particularly excellent in the comprehensive evaluation of "Good". In addition, by using phenylmethyl silicone as the water repellent, the water repellent is less likely to come off than the one using a fluorine-based water repellent or other silicone water repellent (Comparative Example 1-3). be able to. Therefore, it can be used for a long period of time even in a radiation environment.
Furthermore, it can be seen that the water-repellent fiber and water-repellent fiber structure of the present invention are excellent in the rate of change in contact angle (rate of change in water repellency) before and after irradiation. As a result, the water repellency does not decrease even in a high radiation environment, so that contaminated water can be easily removed from the contaminated fiber or fiber structure.

According to the present invention, it is possible to provide a water-repellent fiber and a water-repellent fiber structure that are resistant to deterioration even in a high radiation environment and in an underwater or high-humidity environment, can be used for a long period of time, and have a long life. can.

Claims (7)

At least one fiber selected from wholly aromatic polyamide fiber, polyparaphenylenebenzbisoxazole fiber and wholly aromatic polyester fiber, which has been subjected to plasma treatment or electron beam irradiation treatment, or a fiber structure composed of the fiber, phenyl 1. A water-repellent fiber or a water-repellent fiber structure, characterized in that methylsilicone or phenyl-modified silicone is attached thereto. 2. The water-repellent fiber or water-repellent fiber structure according to claim 1, wherein the phenylmethyl silicone or phenyl-modified silicone has a phenyl group content of 10 mol % or more and 50 mol % or less. 3. The water-repellent fiber or water-repellent fiber structure according to claim 1, wherein the amount of phenylmethyl silicone or phenyl-modified silicone attached is 1% by weight or more and 15% by weight or less based on the weight of the fiber or fiber structure. . The water-repellent fiber or water-repellent fiber structure according to any one of claims 1 to 3, wherein the water repellency change rate determined by formula (I) is 100% or more.
Water repellency change rate (%)=[θ2/θ1]×100 (I)
θ1: contact angle of fiber or fiber structure before irradiation
θ2: Contact angle of fiber or fiber structure after irradiation The water-repellent fiber or water-repellent fiber structure according to any one of claims 1 to 4, wherein the fiber is a wholly aromatic polyamide fiber. A radiation-resistant material using the water-repellent fiber or water-repellent fiber structure according to any one of claims 1 to 5. A first step of subjecting at least one fiber selected from wholly aromatic polyamide fiber, polyparaphenylenebenzbisoxazole fiber and wholly aromatic polyester fiber, or a fiber structure made of said fiber, to plasma treatment or electron beam irradiation treatment. process and
and a second step of applying phenylmethylsilicone or phenyl-modified silicone to the treated surface of the fiber or fiber structure.

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