Water-repellent fiber, water-repellent fiber structure, and method for producing same

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

Technical Field

[0001] The present invention relates to a water-repellent fiber, a water-repellent fiber structure, and a method for producing the same, which can be used in a radiation environment such as nuclear power plants, used nuclear fuel reprocessing facilities, proton accelerators and other nuclear-related facilities, medical sites for radiation therapy, and other industrial and medical radiation inspection machines.

Background Art

[0002] At the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company, a so-called meltdown occurred in which nuclear fuel melted immediately after the large tsunami in March 2011, and countermeasures are being taken. When decommissioning the reactor, it is necessary to remove the melted nuclear fuel from the reactor containment vessel, and the extraction method is being intensively studied. The work of removing nuclear fuel and fuel debris from the reactor building is carried out in a high-radiation environment. Furthermore, since the fuel debris is at the bottom of the reactor containment vessel and covered with cooling water, it is necessary to select and configure equipment used for extraction with materials having excellent radiation resistance and water resistance.

[0003] In particular, metal materials with excellent radiation resistance are mainly used for the materials of robots that perform debris removal work, but organic fibers may also be used from the viewpoints of flexibility and weight reduction. As organic fibers, natural fibers (for example, cotton, hemp, etc.) and synthetic fibers (for example, polyester, polyamide, polyvinyl alcohol fiber, etc.) are common. However, it is known that these natural fibers and synthetic fibers have poor radiation resistance under high radiation. Examples of organic fibers with excellent radiation resistance include 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.

[0004] However, the surfaces of these fibers are not water-repellent, and it can be expected that radioactive substances will adhere to the fiber surfaces or the surfaces of cords or fabrics made of the fibers during the debris removal operation in water containing radioactive substances. The robot for debris removal needs to be taken out of the reactor after being sufficiently decontaminated by washing with water or the like inside the reactor containment vessel, but it is difficult to completely remove the radioactive substances adhering to the fiber surfaces. Therefore, the water repellency of the fiber surfaces is very important from the viewpoint of radioactive substance removal.

[0005] Patent Document 1 proposes a method in which a fiber structure containing polyester fibers, polyamide fibers, and cellulose fibers, which are organic fibers, is immersed in a treatment bath containing a water-repellent agent-containing treatment liquid, and the water-repellent agent is exhausted to perform water-repellent processing. However, these organic fibers are known to be inferior in radiation resistance. Also, as water-repellent agents, polydimethylsiloxane, methylhydrogenpolysiloxane, and amino-modified silicone have been proposed, but most of these water-repellent agents are known to be inferior in radiation resistance and are not suitable for use in a high-radiation environment. Further, although fluorine-based compounds are excellent in water repellency, there is a concern that they may cause stress corrosion of metal materials such as stainless steel due to halogen, and thus they are not suitable for use inside nuclear power plants.

[0006] Patent Document 2 proposes a manufacturing method in which a para-type wholly aromatic polyamide fiber having anhydrous aluminum silicate and / or sodium aluminosilicate adhered to its surface is subjected to plasma treatment to improve adhesiveness. However, there is no mention at all about imparting water repellency, and its effect cannot be expected either.

[0007] Patent Document 3 also proposes a similar technique. That is, a high-strength fiber containing no oil agent is opened as needed to form a filament bundle on a flat plate, and while the filament bundle on the flat plate is running at 3 to 30 m / min, atmospheric pressure plasma treatment under an inert gas is performed on its surface under the condition of a frequency of 3 to 26 Hz. A method for manufacturing a surface-hydrophilized high-strength fiber is proposed. However, there is no mention at all about improving water repellency, and its effect cannot be expected either.

[0008] Patent Document 4 describes a method for producing phenylmethyl silicone, which is a silicone composition for peeling. However, it does not mention anything about radiation resistance or fibers imparted with such property.

[0009] Non-Patent Document 1 proposes the preparation of PET fibers having highly durable water repellency by grafting a fluoropolymer onto a polyester plain woven fabric by electron beam irradiation. However, similar to Patent Document 1, it is inferior in radiation resistance and thus not suitable for use under high radiation.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0011]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0012] In view of the background of such prior art, the present invention aims to provide a water-repellent fiber and a water-repellent fiber structure excellent in water repellency and radiation resistance, which can be used as members of a robot required for debris removal from the reactor containment vessel of the Tokyo Electric Power Fukushima Daiichi Nuclear Power Station and can be used for a long period even under high radiation, and a method for producing the same.

Means for Solving the Problems

[0013] As a result of intensive studies to solve the above problems, the present inventors have found that, unexpectedly, by subjecting an organic fiber excellent in radiation resistance, for example, at least one fiber selected from wholly aromatic polyamide fibers, polyparaphenylene benzobisoxazole fibers, and wholly aromatic polyester fibers or a fiber structure made of the fiber to plasma treatment or electron beam irradiation treatment and then applying phenylmethyl silicone or phenyl-modified silicone to the fiber surface or the fiber structure surface, such problems can be solved all at once, and thus the present invention has been completed.

[0014] That is, the present invention is as follows. (1) A water-repellent fiber or a water-repellent fiber structure, characterized in that at least one fiber selected from wholly aromatic polyamide fibers, polyparaphenylene benzobisoxazole fibers, and wholly aromatic polyester fibers or a fiber structure made of the fiber, which has been subjected to plasma treatment, has phenylmethyl silicone Principle attached thereto. having a phenyl group content of 10 mol% or more and 50 mol% or less amine and the water repellency change rate determined by the following formula (I) is 103% or more having radiation resistance Water repellency change rate (%) = [θ2 / θ1] × 100 ··· (I) θ1: Contact angle of the fiber or fibrous structure before radiation irradiation θ2: Contact angle of the fiber or fibrous structure after radiation irradiation ( 2 ) said The water-repellent fiber or the water-repellent fiber structure according to (1) above, wherein the amount of phenylmethyl silicone amine attached is 1% by weight or more and 15% by weight or less based on the weight of the fiber or the fiber structure. ) to having radiation resistance ( 3 ) said The water-repellent fiber or the water-repellent fiber structure according to (1) above, wherein the fiber is a wholly aromatic polyamide fiber. or (2) having radiation resistance ( 4 ​​​​​​​​At least one fiber selected from wholly aromatic polyamide fibers, polyparaphenylene benzobisoxazole fibers, and wholly aromatic polyester fibers, or a fiber structure made of such fibers is subjected to plasma treatment. Principle The first step of performing the treatment, On the surface of the fiber or fiber structure that has been subjected to the treatment, having a phenyl group content of 10 mol% or more and 50 mol% or less Phenylmethyl silicone amine The second step of applying, and has and characterized in that the water repellency change rate determined by the following formula (I) is 103% or more, having radiation resistance A method for producing a water-repellent fiber or a water-repellent fiber structure. Water repellency change rate (%) = [θ2 / θ1] × 100 ··· (I) θ1: Contact angle of the fiber or fibrous structure before radiation irradiation θ2: Contact angle of the fiber or fibrous structure after radiation irradiation

Advantages of the Invention

[0015] The water-repellent fiber and the water-repellent fiber structure of the present invention are fiber materials that are less likely to deteriorate even in a high-radiation environment and in water or a high-humidity environment, can be used for a long time, and have a long lifespan. In particular, it is suitable as a member of a robot for debris removal in the decommissioning work of nuclear power plants.

Brief Description of the Drawings

[0016]

Figure 1

Embodiments for Carrying Out the Invention

[0017] The water-repellent fiber and the water-repellent fiber structure excellent in radiation resistance of the present invention, and a method for manufacturing the same will be described in detail.

[0018] The water-repellent fiber and the water-repellent fiber structure of the present invention are characterized in that phenylmethyl silicone or phenyl-modified silicone is adhered to a high-strength fiber or a high-strength fiber structure made of such fibers that has been subjected to plasma treatment or electron beam irradiation treatment.

[0019] [High-strength fiber] The present invention uses organic fibers known as so-called wholly aromatic high-strength fibers. Examples of the wholly aromatic high-strength fibers include wholly aromatic polyamide fibers, polyparaphenylene benzobisoxazole fibers, and wholly aromatic polyester fibers, and at least one fiber selected from these wholly aromatic high-strength fibers is used. These fibers have advantages such as high tensile elastic modulus, flexibility, heat resistance, high limiting oxygen index (LOI) value and being difficult to burn, and in addition, they have excellent radiation resistance. In particular, the radiation resistance performance is several times or more that of other organic fibers. Among them, it is preferable to use wholly aromatic polyamide fibers from the viewpoint of excellent strength characteristics. Commercially available products may be used as the wholly aromatic high-strength fibers. In the following, the above-mentioned wholly aromatic high-strength fibers are referred to as "high-strength fibers", and the wholly aromatic high-strength fiber structure made of the fibers is referred to as "high-strength fiber structure". In addition, the high-strength fibers and the high-strength fiber structures may be collectively referred to as "high-strength fibers, etc.".

[0020] The wholly aromatic polyamide fiber is a fiber having at least one divalent aromatic group which may be usually substituted, and there is no particular limitation as long as it has at least one amide bond, and it may be a known one called a wholly aromatic polyamide fiber. In the above, the "divalent aromatic group which may be substituted" means a divalent aromatic group which may have one or more substituents which are the same or different.

[0021] The wholly aromatic polyamide fiber is also called an aramid fiber. The aramid fiber can be roughly classified into para-aramid fiber or meta-aramid fiber. Examples of the para-aramid fiber include polyparaphenylene terephthalamide fiber (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark), etc.), copolyparaphenylene-3,4'-oxydiphenylene terephthalamide fiber (manufactured by Teijin Limited, trade name "Technora" (registered trademark), etc.). Examples of meta-aramid fibers include polymetaphenylene isophthalamide fibers (manufactured by DuPont, trade name "Nomex"), fibers manufactured by Teijin Limited (trade name "Conex"), and the like. Among them, para-aramid fibers are preferably used because of their excellent tensile strength, and polyparaphenylene terephthalamide fibers are more preferable.

[0022] Examples of polyparabenzbisoxazole fibers include fibers manufactured by Toyobo Co., Ltd. (trade name "Zylon"), and examples of wholly aromatic polyester fibers include fibers manufactured by Kuraray Co., Ltd. (trade name "Vectran"), and the like.

[0023] The high-strength fibers of the present invention are used in the form of fibers or fiber structures composed of the fibers. Examples of the form of the high-strength fibers include filaments or filament bundles, staple fibers, and the like. Examples of the form of the high-strength fiber structure include woven fabrics, knitted fabrics, braided fabrics, honeycomb-like structures, non-woven fabrics, cords, ropes, nets, and the like.

[0024] From the viewpoint of strength, it is preferable that the fineness of the high-strength fibers is thick, but if it is too thick, the processability into fiber structures will be poor. From an economic viewpoint, 110 dtex or more is preferable, more preferably 110 dtex to 6400 dtex, and even more preferably 420 dtex to 3300 dtex.

[0025] The basis weight of the high-strength fiber structure is preferably 50 g / m 2 ~1000 g / m 2 When aramid fibers are used, even if the basis weight is 50 g / m 2 it is possible to sufficiently maintain the tensile strength of the fiber structure, thereby enabling the production of a lightweight and high-strength fiber structure, which is particularly suitable. Also, if the basis weight is 1000 g / m 2 or less, a fiber structure having no problem in terms of lightness and flexural fatigue resistance can be obtained. From the viewpoint of the balance between the tensile strength and lightness and flexural fatigue resistance, the basis weight of the high-strength fiber structure is more preferably 75 g / m 2 ~700 g / m2 , more preferably 100 g / m 2 ~500 g / m 2 .

[0026] [Surface treatment] Before performing the water-repellent agent application treatment, in order to improve the adhesiveness of the surface of high-strength fibers or the like, plasma treatment or electron beam irradiation treatment is performed (first step). Here, by applying the water-repellent agent described later to the high-strength fibers or the like of the present invention without performing surface treatment, water repellency can be temporarily imparted. However, in this method, the adhesive force between the water-repellent agent and the fiber surface is poor, and when the fiber surface is rubbed, the water-repellent agent falls off, and the water-repellent effect is impaired. Therefore, in order to improve the adhesiveness between the water-repellent agent and the fiber, a method of etching by allowing an acid or an alkali to act on the fiber surface may be used. However, it is known that this method cannot deny the influence not only on the fiber surface but also on the inside of the fiber, and as a result, a decrease in the strength of the fiber occurs. In the present invention, in order to avoid such a decrease in strength, the surface of high-strength fibers or the like is modified by performing plasma treatment or electron beam irradiation treatment that affects only the surface layer of the fiber, and the adhesiveness with the water-repellent agent can be significantly improved. Plasma treatment and electron beam irradiation treatment are preferably performed while transporting the fiber or fiber structure from the viewpoint of reducing the treatment unevenness on the fiber surface and the treatment efficiency.

[0027] As the plasma treatment, conventionally known treatments may be employed. For example, atmospheric pressure plasma treatment (atmospheric pressure plasma treatment) and low pressure plasma treatment (vacuum plasma treatment) can be mentioned. Further, as the plasma irradiation device used for plasma treatment, a high-frequency induction method, a capacitively coupled electrode method, a corona discharge electrode - plasma jet method, a parallel plate type, a remote plasma type, an atmospheric pressure plasma type, an ICP type high-density plasma type, etc. can be mentioned. These treatment methods and treatment devices are appropriately selected and used. Among these, atmospheric pressure plasma treatment by glow discharge performed at a pressure near atmospheric pressure or atmospheric pressure is preferable. Performing at near atmospheric pressure has the advantage that large-scale equipment and complicated operations such as vacuum equipment and vacuum operations are not required. Atmospheric pressure or the pressure near atmospheric pressure means 1.333×104 ~10.664×10 4 Pa, which means easy pressure adjustment and discharge can be achieved with a simple device, 9.331×10 4 ~10.397×10 4 Pa is preferred.

[0028] As plasma treatment methods, there are direct and remote methods, but the plasma treatment 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 arranged between parallel plate electrodes for treatment. Since continuous fibers etc. are directly introduced into the plasma atmosphere, generally the treatment effect is high and various surface modification conditions can be set. The remote method is a method in which the plasma generated between electrodes is sprayed onto fibers etc. for treatment. Considering the possible damage to fibers etc. caused by plasma treatment, the remote method with less damage is preferred.

[0029] By plasma treatment, various functional groups can be imparted to the surface of fibers etc. For example, after nitrogen plasma treatment, the composition ratio of nitrogen becomes larger compared to before treatment. According to the XPS (X-ray photo-electron spectroscopy) analysis results, it is presumed that functional groups such as -C-N, -C-O, -C=O, -CON, -COO are formed on the surface of the plasma-treated fibers.

[0030] The frequency of plasma treatment is preferably carried out at 3 kHz to 26 kHz. If the frequency exceeds 26 kHz, electrons and ions are accelerated and collide with the fiber surface at high speed, which may cut the 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, the acceleration of electrons and ions is insufficient, resulting in insufficient treatment of the fiber surface.

[0031] The plasma irradiation time for plasma treatment is preferably from 0.3 seconds to 8 seconds. More preferably, it is from 0.4 seconds to 6 seconds, and particularly preferably from 0.5 seconds to 5 seconds. If it is 0.3 seconds or more, the treatment of the fiber surface will not be insufficient, and the water repellent can be firmly adhered, so there is no fear of the water repellent falling off. Also, if it is 8 seconds or less, it is possible to prevent a decrease in the tensile strength of high-strength fibers and the like due to plasma treatment, and it is possible to prevent an increase in the treatment time and cost, so there is no fear of impairing economic efficiency.

[0032] The atmosphere (treatment gas) during plasma treatment is a gas that generates plasma by applying an electric field, for example, air, oxygen, nitrogen, argon, helium, carbon dioxide, etc. These may be used alone or two or more of them may be mixed and used. Among them, it is preferable to use nitrogen because plasma treatment can be performed with high power, from the viewpoint of safety, and the price of the gas alone is low.

[0033] [Water repellent] In the present invention, a water-repellent or a water-repellent fiber structure is produced by applying phenylmethyl silicone or phenyl-modified silicone to the surface of a fiber or a fiber structure that has been subjected to plasma treatment or electron beam irradiation treatment in the first step (second step). Examples of the water repellent include hydrocarbon-based compounds, polydimethylsiloxane, methylhydrogenpolysiloxane, amino-modified silicone, etc. These water repellents are known to be inferior in radiation resistance and are not suitable for use in a high-radiation environment. For example, hydrocarbon-based compounds are said to have problems in radiation resistance. Also, dimethylsilicone-based compounds are generally said to be inferior in radiation resistance, but phenylmethyl silicone is said to be superior in radiation resistance to other silicones. Also, fluorine-based compounds are excellent in water repellency, but are not suitable for use in nuclear power plants due to concerns about stress corrosion of metals such as stainless steel by halogens in nuclear power plants.

[0034] When investigating compounds having both water repellency and radiation resistance, it has been found that phenylmethyl silicone or phenyl-modified silicone is preferable. Phenylmethyl silicone is represented by, for example, Chemical Formula (Chemical Formula 1) and Chemical Formula (Chemical Formula 2). As the phenyl-modified silicone, for example, BESIL (registered trademark) phenyl-modified silicone (manufactured by Shin-Etsu Silicone Co., Ltd.) and the like are known. In the present invention, phenylmethyl silicone is preferable. [Chemical Formula] [Chemical Formula]

[0035] The phenyl group content of 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. Even more preferably, it is 25 mol% or more and 40 mol% or less. If the phenyl group content is within the above range, there is no fear of a decrease in water repellency even in a high-radiation environment. Phenylmethyl silicone and phenyl-modified silicone are preferably used in the state of straight oil or aqueous emulsion.

[0036] The adhesion amount of phenylmethyl silicone and phenyl-modified silicone is preferably 1% by weight or more and 15% by weight or less based on the weight of the fiber or fiber structure. If it is 1% by weight or more, sufficient water repellent performance can be exhibited. Also, if it is 15% by weight or less, there is no fear of the water repellent agent falling 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 even more preferably 2% by weight or more and 12% by weight or less.

[0037] Next is the process of applying a water repellent agent. The method of applying the water repellent agent is not particularly limited, and any conventionally known method may be adopted. For example, dipping method, spraying method, roller method, guide method using a metering pump, etc. may be mentioned. Usually, it is applied at room temperature of about 10 to 40 °C, but the conditions such as temperature may be appropriately adjusted to adjust the adhesion amount.

[0038] In the present invention, the water repellent agent treatment may be performed on the high-strength fibers themselves such as aramid fibers that have been subjected to plasma treatment or electron beam irradiation treatment, or the water repellent agent treatment may be performed on a high-strength fiber structure made of high-strength fibers.

[0039] [Water-repellent fibers and water-repellent fiber structures] The water-repellent fibers and water-repellent fiber structures 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 fiber or fiber structure and pure water when pure water is dropped on the water-repellent fiber or water-repellent fiber structure before and after radiation 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, and even more preferably 105% or more. The higher the water repellency change rate, the more the water repellency is improved after working in a high-radiation environment, and the easier it is to remove contaminated water from the contaminated fiber or fiber structure. Water repellency change rate (%) = [θ2 / θ1] × 100 ··· (I) θ1: Contact angle of the fiber or fiber structure before radiation irradiation θ2: Contact angle of the fiber or fiber structure after radiation irradiation

[0040] The water-repellent fibers and water-repellent fiber structures of the present invention have excellent water repellency, radiation resistance, and further high strength characteristics, tensile elastic modulus, heat resistance, and flame retardancy. Therefore, they can be widely used in various forms and for various applications. In particular, they are suitable as members of debris removal robots and water bags in the decommissioning work of nuclear power plants.

Examples

[0041] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. The evaluation methods and measurement methods described in the examples are as follows.

[0042] (Evaluation of radiation resistance) Regarding the evaluation of radiation resistance, after irradiating the fiber or fiber structure provided with the water repellent agent with radiation, a tensile test of the fiber or fiber structure was performed to compare and evaluate the tensile strength before and after the radiation irradiation. The radiation irradiation was performed with γ-rays (Co60) at room temperature (in air), and the irradiation was completed when the cumulative absorbed dose reached 100 kGy. The strength retention rate after irradiation was ranked as × if it was less than 70% of that before irradiation, △ if it was 70% or more and less than 95%, and ○ if it was 95% or more.

[0043] (Measurement method of contact angle) As the measuring device, a portable contact angle meter PG-X manufactured by FIBROsystem AB (Sweden) was used. For the measurement, the measuring device was set on the yarn in which the samples were aligned and wound, pure water was dropped onto the yarn, and the contact angle between the aligned yarn row and the pure water was detected. Note that the smaller the contact angle value, the more hydrophilic the surface, and the larger the contact angle value, the more water-repellent the surface. The contact angle was ranked as × if it was less than 80°, △ if it was 80° or more and less than 90°, and ○ if it was 90° or more.

[0044] (Evaluation of water repellent agent dropout) The fiber provided with the water repellent agent is set in a rewinder, and rewinding is performed under a certain tension, and the amount of scum (dropout) generated at the guide is measured to evaluate the dropout of the water repellent agent using the apparatus shown in Fig. 1. The raw yarn wound around the paper tube is passed through roller guides, rollers 1 to 3 and the yarn, bent at about 90 degrees at the ring guide, the yarn is rubbed at the guide, and scum accumulates on the guide. Then, it passes through rollers 4 to 7, a tension of 250 g is applied by a tension device, passes through roller 8, and is wound up by a winder at a speed of 50 m / min. The tension device is adjusted so that the tension between roller 3 and the ring guide becomes 250 g. After 1 minute of rubbing, the weight of the 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

[0045] (Example 1) 1000 m of wholly aromatic polyamide fiber with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark)) was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to carry out the treatment under a nitrogen atmosphere. Tensions were applied to the reels on the unwinding side and the winding side, and the fiber was subjected to plasma treatment for 1 second while being conveyed. The treated fiber was wound onto a reel with a width of 10 cm. Subsequently, a water repellent was applied to the plasma-treated fiber. As the water repellent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The water repellent is a methyl silicone containing 35 mol% of phenyl groups and is sold as a straight oil. The above water repellent was applied to the plasma-treated fiber so that the adhesion amount was 10 w / w%, and hot air drying was carried out to adhere the water repellent to the fiber surface to produce a water-repellent fiber. The radiation resistance (strength retention rate), water repellency (contact angle), and water repellent dropout property of the produced water-repellent fiber were evaluated.

[0046] (Example 2) 1000 m of wholly aromatic polyamide fiber with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark)) was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to conduct the treatment under a nitrogen atmosphere. Tension was applied to the reels on the unwinding side and the winding side, and the fiber was transported while being subjected to plasma treatment for 2 seconds. The treated fiber was wound onto a reel with a width of 10 cm. Subsequently, a water repellent was applied to the plasma-treated fiber. As the water repellent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent 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 to the fiber surface, thereby producing water-repellent fiber. The radiation resistance (strength retention rate), water repellency (contact angle), and water repellent detachment property of the produced water-repellent fiber were evaluated.

[0047] (Example 3) 1000 m of wholly aromatic polyamide fiber with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR (registered trademark)") was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to conduct the treatment under a nitrogen atmosphere. Tension was applied to the reels on the unwinding side and the winding side, and the fiber was transported while being subjected to plasma treatment for 4 seconds. The treated fiber was wound onto a reel with a width of 10 cm. Subsequently, a water repellent was applied to the plasma-treated fiber. As the water repellent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent 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 to the fiber surface, thereby producing water-repellent fiber. The radiation resistance (strength retention rate), water repellency (contact angle), and water repellent detachment property of the produced water-repellent fiber were evaluated.

[0048] (Example 4) 1000 m of wholly aromatic polyester fiber with a fineness of 1580 dtex (manufactured by Kuraray Co., Ltd., trade name "Vectran" (registered trademark)) was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at a rate of 25 L / min each to conduct the treatment under a nitrogen atmosphere. Tensions were applied to the reels on the unwinding side and the winding side, and the fiber was subjected to plasma treatment for 1 second while being transported. The treated fiber was wound onto a reel with a width of 10 cm. Subsequently, a water-repellent agent was applied to the plasma-treated fiber. As the water-repellent agent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water-repellent agent was applied to the plasma-treated fiber so that the adhesion amount would be 10 w / w%, and hot air drying was performed to adhere the water-repellent agent to the fiber surface, thereby producing water-repellent fiber. The water-repellent fiber produced was evaluated for radiation resistance (strength retention rate), water repellency (contact angle), and water-repellent agent dropout.

[0049] (Example 5) 1000 m of wholly aromatic polyester fiber with a fineness of 1580 dtex (manufactured by Kuraray Co., Ltd., trade name "Vectran" (registered trademark)) was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at a rate of 25 L / min each to conduct the treatment under a nitrogen atmosphere. Tensions were applied to the reels on the unwinding side and the winding side, and the fiber was subjected to plasma treatment for 2 seconds while being transported. The treated fiber was wound onto a reel with a width of 10 cm. Subsequently, a water-repellent agent was applied to the plasma-treated fiber. As the water-repellent agent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water-repellent agent was applied to the plasma-treated fiber so that the adhesion amount would be 10 w / w%, and hot air drying was performed to adhere the water-repellent agent to the fiber surface, thereby producing water-repellent fiber. The water-repellent fibers produced were evaluated for radiation resistance (strength retention rate), water repellency (contact angle), and water repellent shedding property.

[0050] (Example 6) 1000 m of wholly aromatic polyester fiber with a fineness of 1580 dtex (manufactured by Kuraray Co., Ltd., trade name "Vectran" (registered trademark)) was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to conduct the treatment under a nitrogen atmosphere. Tension was applied to the reels on the unwinding side and the winding side, and the fiber was plasma-treated for 4 seconds while being conveyed. The treated fiber was wound onto a reel with a width of 10 cm. Subsequently, the plasma-treated fiber was given a water repellent. As the water repellent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent 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 to the fiber surface, thereby producing water-repellent fibers. The water-repellent fibers produced were evaluated for radiation resistance (strength retention rate), water repellency (contact angle), and water repellent shedding property.

[0051] (Example 7) 1000 m of wholly aromatic polyamide fiber with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark)) was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to conduct the treatment under a nitrogen atmosphere. Tension was applied to the reels on the unwinding side and the winding side, and the fiber was plasma-treated for 2 seconds while being conveyed. The treated fiber was wound onto a reel with a width of 10 cm. The plasma-treated fibers were subsequently treated with a water repellent. As the water repellent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent was applied to the plasma-treated fibers so that the adhesion amount was 1 w / w%, and hot air drying was performed to adhere the water repellent to the fiber surface, thereby producing water-repellent fibers. The prepared water-repellent fibers were evaluated for radiation resistance (strength retention rate), water repellency (contact angle), and water repellent shedding property.

[0052] (Example 8) 1000 m of wholly aromatic polyamide fiber with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark)) was wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to conduct the treatment under a nitrogen atmosphere. Tensions were applied to the reels on the unwinding side and the winding side, and the fibers were subjected to plasma treatment for 2 seconds while being conveyed. The treated fibers were wound onto a reel with a width of 10 cm. The plasma-treated fibers were subsequently treated with a water repellent. As the water repellent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent was applied to the plasma-treated fibers so that the adhesion amount was 20 w / w%, and hot air drying was performed to adhere the water repellent to the fiber surface, thereby producing water-repellent fibers. The prepared water-repellent fibers were evaluated for radiation resistance (strength retention rate), water repellency (contact angle), and water repellent shedding property.

[0053] (Example 9) A woven fabric made of wholly aromatic polyamide fiber (plain weave fabric made of KEVLAR (registered trademark), basis weight 220 g / m 2 ) was cut into a 30 cm square and subjected to plasma treatment. Under atmospheric pressure, plasma treatment was carried out as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to conduct the treatment under a nitrogen atmosphere. The fabric was fixed to the plasma processor and subjected to plasma treatment for 1 second. Subsequently, a water-repellent agent was applied to the plasma-treated fabric. As the water-repellent agent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water-repellent agent was applied to the plasma-treated fabric in the state of an aqueous emulsion so that the adhesion amount became 3 w / w%, and hot air drying was performed to attach the water-repellent agent to the fabric surface, thereby producing a water-repellent fabric (water-repellent fiber structure). The water-repellent fabric produced was evaluated for radiation resistance (strength retention rate) and water repellency (contact angle).

[0054] (Example 10) A woven fabric made of wholly aromatic polyamide fiber (plain weave fabric made of KEVLAR (registered trademark), basis weight 220 g / m 2 ) was cut into a 30 cm square and subjected to plasma treatment. Under atmospheric pressure, plasma treatment was carried out as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to conduct the treatment under a nitrogen atmosphere. The fabric was fixed to the plasma processor and subjected to plasma treatment for 2 seconds. Subsequently, a water-repellent agent was applied to the plasma-treated fabric. As the water-repellent agent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water-repellent agent was applied to the plasma-treated fabric in the state of an aqueous emulsion so that the adhesion amount became 3 w / w%, and hot air drying was performed to attach the water-repellent agent to the fabric surface, thereby producing a water-repellent fabric (water-repellent fiber structure). The water-repellent fabric produced was evaluated for radiation resistance (strength retention rate) and water repellency (contact angle).

[0055] (Example 11) A woven fabric made of wholly aromatic polyamide fiber (plain weave fabric made of KEVLAR (registered trademark), basis weight 220 g / m 2) was cut into a 30 cm square and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to perform the treatment under a nitrogen atmosphere. The fabric was fixed to the plasma processor and subjected to plasma treatment for 4 seconds. Subsequently, a water repellent was applied to the plasma-treated fabric. As the water repellent, phenylmethyl silicone oil (trade name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent was applied to the plasma-treated fabric in the state of an aqueous emulsion so that the adhesion amount became 3 w / w%, and hot air drying was performed to adhere the water repellent to the fabric surface, thereby producing a water-repellent fabric (water-repellent fiber structure). The water-repellent fabric produced was evaluated for radiation resistance (strength retention rate) and water repellency (contact angle).

[0056] (Comparative Example 1) 1000 m of wholly aromatic polyamide fiber with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark)) was wound around a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to perform the treatment under a nitrogen atmosphere. Tensions were applied to the reels on the unwinding side and the winding side, and the fiber was subjected to plasma treatment for 2 seconds while being conveyed. The treated fiber was wound around a reel with a width of 10 cm. Subsequently, a water repellent was applied to the plasma-treated fiber. As the water repellent, a 15% diluted solution of a fluororesin emulsion (trade name; M Guard PF-11) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used. The above water repellent was applied to the plasma-treated fiber so that the adhesion amount became 3 w / w%, and hot air drying was performed to adhere the water repellent to the fiber surface, thereby producing a water-repellent fiber. The water-repellent fiber produced was evaluated for radiation resistance (strength retention rate), water repellency (contact angle), and water repellent dropout property.

[0057] (Comparative Example 2) A woven fabric made of wholly aromatic polyamide fibers (a plain weave fabric made of KEVLAR (registered trademark), basis weight 220 g / m 2 ) was cut into a 30 cm square and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to carry out the treatment under a nitrogen atmosphere. The woven fabric was fixed to a plasma processor and subjected to plasma treatment for 2 seconds. Subsequently, a water-repellent agent was applied to the plasma-treated woven fabric. As the water-repellent agent, a 15% dilution of a fluororesin emulsion (trade name; M Guard PF-11) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used. The above water-repellent agent was applied to the plasma-treated woven fabric so that the adhesion amount was 3 w / w%, and hot air drying was carried out to adhere the water-repellent agent to the surface of the woven fabric, thereby producing a water-repellent woven fabric (water-repellent fiber structure). The water-repellent woven fabric produced was evaluated for radiation resistance (strength retention rate) and water repellency (contact angle).

[0058] (Comparative Example 3) 1000 m of wholly aromatic polyamide fibers with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., trade name "KEVLAR" (registered trademark)) were wound onto a reel and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to carry out the treatment under a nitrogen atmosphere. Tensions were applied to the reels on the unwinding side and the winding side, and the fibers were transported while being subjected to plasma treatment for 2 seconds. The treated fibers were wound onto a reel with a width of 10 cm. Subsequently, a water-repellent agent was applied to the plasma-treated fibers. As the water-repellent agent, a 20% dilution of a silicone resin emulsion (trade name; M Guard NFC-30) manufactured by Matsumoto Yushi Seiyaku Co., Ltd. was used. The above water-repellent agent was applied to the plasma-treated fibers so that the adhesion amount was 4 w / w%, and hot air drying was carried out to adhere the water-repellent agent to the surface of the fibers, thereby producing water-repellent fibers. The water-repellent fibers produced were evaluated for radiation resistance (strength retention rate), water repellency (contact angle), and water-repellent agent shedding property.

[0059] (Comparative Example 4) Nylon fibers with a fineness of 2150 dtex (product name "Promilan" manufactured by Toray Industries, Inc.) were wound onto a reel for 1000 m and subjected to plasma treatment. The plasma treatment was carried out under atmospheric pressure as follows. The chamber for plasma treatment was shielded from the outside air, and nitrogen gas was purged into it at 25 L / min each to carry out the treatment under a nitrogen atmosphere. Tensions were applied to the reels on the unwinding side and the winding side, and the fibers were subjected to plasma treatment for 2 seconds while being conveyed. The treated fibers were wound onto a reel with a width of 10 cm. The plasma-treated fibers were subsequently treated with a water repellent. As the water repellent, phenylmethyl silicone oil (product name; DOWSIL SH710 Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The water repellent is a methyl silicone containing 35 mol% of phenyl groups and is sold as a straight oil. The plasma-treated Nylon fibers were treated with the above water repellent so that the adhesion amount was 10 w / w%, and hot air drying was carried out to adhere the water repellent to the fiber surface to produce water-repellent fibers. For the produced water-repellent fibers, the radiation resistance (strength retention rate), water repellency (contact angle), and water repellent detachment were evaluated.

[0060] (Comparative Example 5) All aromatic polyamide fibers with a fineness of 1670 dtex (manufactured by Toray DuPont Co., Ltd., product name "KEVLAR" (registered trademark)) were wound onto a reel for 1000 m and treated with a water repellent. Tension was applied to the reels on the unwinding side and the winding side, and the above-mentioned fibers were conveyed at a speed of 6 m / min. Without performing plasma treatment, water repellent was applied. The fibers after the application of the water repellent were wound around a reel with a width of 10 cm. As the water repellent, phenylmethyl silicone oil (product name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent was applied to the aramid fibers without plasma treatment so that the adhesion amount was 10 w / w%, and hot air drying was performed to adhere the water repellent to the fiber surface, thereby producing water repellent fibers. For the produced water repellent fibers, the radiation resistance (strength retention rate), water repellency (contact angle), and water repellent shedding property were evaluated.

[0061] (Comparative Example 6) A woven fabric made of wholly aromatic polyamide fiber (plain weave fabric made of KEVLAR (registered trademark), basis weight 220 g / m 2 ) was cut into a 30 cm square, and water repellent was applied without performing plasma treatment. As the water repellent, phenylmethyl silicone oil (product name; DOWSIL SH710Fluid) manufactured by Dow Corning Toray Co., Ltd. was used. The above water repellent was applied to the fabric without plasma treatment in the state of an aqueous emulsion so that the adhesion amount was 3 w / w%, and hot air drying was performed to adhere the water repellent to the fabric surface, thereby producing a water repellent fabric (water repellent fiber structure). For the produced water repellent fabric, the radiation resistance (strength retention rate) and water repellency (contact angle) were evaluated.

[0062] The treatment conditions and water repellent adhesion amounts of the examples and comparative examples are shown in Table 1.

[0063]

Table 1

[0064] The evaluation results of the examples and comparative examples are shown in Table 2.

[0065]

Table 2

[0066] 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 the retention rate of strength and water repellency after radiation irradiation, and also excellent in the water-repellent agent dropout property. Among them, it can be seen that Examples 1-3 and Example 7 are particularly excellent with a comprehensive evaluation of "○". In addition, by using phenylmethyl silicone as the water-repellent agent, the water-repellent agent dropout property can be suppressed to a lower level compared with those using fluorine-based water-repellent agents or other silicone-based water-repellent agents (Comparative Examples 1-3). Therefore, it can be used for a long time even in a radiation environment. Furthermore, it can be seen that the water-repellent fibers and water-repellent fiber structures of the present invention are excellent in the change rate of the contact angle (water-repellency change rate) before and after radiation irradiation. As a result, since the water repellency does not decrease even in a high-radiation environment, it is possible to easily remove contaminated water from the contaminated fibers or fiber structures.

Industrial Applicability

[0067] According to the present invention, it is possible to provide water-repellent fibers and water-repellent fiber structures that are less likely to deteriorate even in a high-radiation environment, in water, or in a high-humidity environment, can be used for a long time, and have a long lifespan.

Claims

1. A water-repellent fiber or fiber structure having radiation resistance, comprising at least one fiber selected from wholly aromatic polyamide fibers, polyparaphenylene benzbisoxazole fibers, and wholly aromatic polyester fibers that have been subjected to a plasma treatment, or a fiber structure comprising such fibers, and having a phenylmethylsilicone having a phenyl group content of 10 mol % or more and 50 mol % or less adhered thereto, the water-repellency change rate calculated by the following formula (I) being 103% 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

2. A radiation-resistant, water-repellent fiber or fiber structure as described in claim 1, wherein the amount of phenylmethyl silicone attached is 1% by weight or more and 15% by weight or less based on the weight of the fiber or fiber structure.

3. A radiation-resistant, water-repellent fiber or fiber structure as described in claim 1 or 2, wherein the fiber is a fully aromatic polyamide fiber.

4. A first step of subjecting at least one type of fiber selected from wholly aromatic polyamide fibers, polyparaphenylene benzbisoxazole fibers, and wholly aromatic polyester fibers, or a fiber structure comprising such fibers, to a plasma treatment; and a second step of applying a phenylmethylsilicone having a phenyl group content of 10 mol % or more and 50 mol % or less to the surface of the fiber or fiber structure that has been subjected to the treatment, A method for producing a radiation-resistant water-repellent fiber or fiber structure, characterized in that the rate of change in water repellency determined by the following formula (I) is 103% 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

Images