JP2006328599A - Monofilament with high abrasion resistance and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide monofilament improved in abrasion resistance to the utmost and free of problems of fibrillation and scumming in undergoing weaving. <P>SOLUTION: The monofilament has a fineness of 5-1,000 dtex. There are asperities 10 nm to 1μm in size on the surface thereof, and the surface thereof is coated with a metal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a monofilament excellent in wear resistance and a method for producing the same, and more specifically, the surface of the monofilament is roughened by a plasma irradiation treatment, and the surface of the monofilament is electrolessly plated and / or electroplated. The present invention relates to a monofilament coated with a metal by a method and a method for producing the same.

Monofilaments are woven into high-precision woven fabrics and used for applications such as screen wrinkles and various filters. In general, polyamide and polyester monofilaments, stainless steel wires, etc. are used as general-purpose products in such applications, but they are used in screen applications that require higher dimensional accuracy and durability, and in more severe conditions. In such filter applications, higher heat resistance, chemical resistance, dimensional stability, and the like are required. Therefore, there is a problem that the above-described materials cannot sufficiently satisfy these characteristics.
For this reason, monofilaments such as para-aramid fibers and polyarylate fibers having high mechanical properties and excellent heat resistance and chemical resistance are used for these applications.

  However, in general, such monofilaments of high-strength and high-modulus fibers are very weak against a force perpendicular to the fiber axis because the molecular chains are highly oriented in the fiber axis direction. There is a disadvantage that the fiber is easily fibrillated. For this reason, when weaving such monofilaments, there is a problem that the fibers are worn by friction between warps and wefts and friction between the heels, and fibrils and scum are easily generated.

  In order to overcome such drawbacks, Japanese Patent Application Laid-Open No. 8-260249 discloses an island made of an aromatic polyester as a core component and a sea component and an aromatic polyester as a sheath component made of a flexible thermoplastic polymer. A core-sheath composite fiber having a sea-island structure composed of components is disclosed.

  In the fiber, since most of the fiber surface is composed of a flexible thermoplastic polymer, it has excellent wear resistance, and the sheath component contains the same aromatic polyester as the core component. Therefore, separation between the core and the sheath is less likely to occur. However, in order to produce such fibers, existing apparatuses cannot be used as they are, and new capital investment for installing special spinning facilities is required. Further, since the matrix of the sheath component is a thermoplastic polymer, it does not have the mechanical properties and heat resistance as the core component, so that the core component characteristics cannot be fully exhibited. Furthermore, in the case where yarn is produced by a dry and / or wet spinning method using a dope obtained by dissolving a polymer in an organic solvent or sulfuric acid, such as para-aramid fiber, it is very difficult to produce a monofilament having a core-sheath structure. Had the problem of being.

  JP-A-11-269737 discloses a monofilament in which high-strength fibers are coated with polysiloxane and / or fluorine-based resin. In this method, the resin can be attached to the surface of the monofilament by a simple treatment, and since the resin is excellent in wear resistance, weaving can be expected to be improved. There is a drawback that the strength of the resin layer is not sufficient when the molecular structure or the crosslinking reaction due to the addition of a metal catalyst does not occur sufficiently.

  Furthermore, when the fluororesin is coated, in order to fully exhibit the characteristics of the fluororesin, it is necessary to perform firing at a temperature of 350 ° C. or more, and at that time, the monofilament may be deteriorated. Further, since the fluororesin has a low surface tension, there is a problem that the adhesiveness with the emulsion is deteriorated and it is not suitable for a printing screen.

  Furthermore, Japanese Patent Application Laid-Open No. 60-200767 discloses a method in which the surface of a substrate such as an organic polymer sheet is subjected to plasma irradiation treatment and metal plating is performed by an electroless method. However, this method mainly aims to impart conductivity to the substrate and improve aesthetics, and it is unclear whether this can be applied to improve the wear resistance of monofilaments. .

  As described above, a method for efficiently improving the wear resistance of a monofilament that easily causes fibrillation has not been known, and development of a method for producing such a monofilament has been strongly demanded.

JP-A-8-260249 JP-A-11-269737 JP-A-60-200767

  An object of the present invention is to provide a monofilament that solves the above-mentioned problems of the prior art, has as much wear resistance as possible, and has no problems of fibrillation and scum generation during weaving.

  As a result of intensive studies to achieve the above object, the present inventors have found that a desired monofilament can be obtained when the monofilament surface is roughened by plasma treatment prior to metal coating on the monofilament surface. The present invention has been reached.

  Thus, according to the present invention, the monofilament has a fineness of 5 to 1000 dtex, the monofilament surface has irregularities with a size of 10 nm to 1 μm, and the monofilament surface is coated with metal. A monofilament having excellent wear resistance is provided.

  According to the present invention, the surface of a monofilament having a fineness of 5 to 1000 dtex is subjected to plasma irradiation treatment to form irregularities with a size of 10 nm to 1 μm, and then coated with a metal by an electroless plating method and / or an electrolytic plating method. A method for producing a monofilament having excellent wear resistance is provided.

  According to the present invention, a monofilament having improved wear resistance as much as possible and free from problems of fibrillation and scum generation during weaving is provided. It can be suitably used for filter applications that are used under more severe conditions.

  The monofilament used in the present invention is not particularly limited. For example, any organic fiber monofilament such as para-aramid fiber, polyarylate fiber, polybenzazole fiber, polyester fiber, polyamide fiber, polyketone fiber, polyethylene fiber, and polyvinyl alcohol fiber can be used. Among them, a particularly remarkable effect can be seen when monofilaments of para-aramid fibers, polyarylate fibers, and polybenzazole fibers, which are generally considered to be easily fibrillated with high-strength and high-modulus fibers, are used.

  Here, as specific examples of para-aramid fibers, polyparaphenylene terephthalamide and copolyparaphenylene-3,4′oxydiphenylene-terephthalamide are used, and polyarylate fibers are wholly aromatic polyesters and polybenzazole fibers. Examples thereof include polyparaphenylene benzobisoxazole and polyparaphenylene benzobisthiazole.

  The fineness of the monofilament used in the present invention is a monofilament of 5 to 1000 dtex, preferably 10 to 100 dtex, more preferably 10 to 50 dtex. When the fineness of the monofilament is less than 5 dtex, although it depends on the constituent material of the fiber, generally a high spinning technique is required, and it is difficult not only to produce the yarn at the production level, but also to break the yarn by roughening by plasma irradiation. Is likely to occur.

  On the other hand, when the fineness of the monofilament exceeds 1000 dtex, the surface area of the monofilament becomes large, and it becomes difficult to uniformly roughen the entire surface. However, even if a monofilament having a fineness outside the above range is subjected to the same treatment, the effect of improving the abrasion resistance can be expected. Therefore, the monofilament having a fineness outside the above range may be treated.

  The monofilament defined in the present invention is a long fiber composed of a single filament, and the cross-sectional shape, fiber properties, fine structure, polymer properties (terminal carboxyl group concentration, molecular weight, etc.), presence or absence of additives in the polymer, etc. Is not limited at all.

In the present invention, unevenness is imparted to the entire monofilament surface by plasma irradiation treatment described later, and the size of the unevenness is 10 nm to 1 μm, preferably 10 nm to 500 nm, and more preferably 10 nm to 300 nm. When the size of the unevenness is less than 10 nm, the time required for the plasma irradiation process becomes long, and the processing efficiency is greatly reduced. On the other hand, when the size of the unevenness exceeds 1 μm, the contact area of the monofilament / metal layer becomes small, so that sufficient adhesion cannot be obtained and the metal layer may be easily peeled off.
The size of the irregularities is the average value of 20 irregularities observed by observing the monofilament surface with a scanning electron microscope (SEM).

  Furthermore, in the present invention, metal is coated on the entire monofilament surface provided with irregularities by plasma irradiation treatment, which is described later, and the thickness of the coated metal layer is preferably 100 nm to 2 μm. More preferably, it is 500 nm-1 micrometer. When the thickness of the metal layer is less than 100 nm, the thickness of the metal layer may be too thin to contribute to the improvement in wear resistance of the monofilament. On the other hand, when the thickness of the metal layer exceeds 2 μm, although the wear resistance is sufficiently improved, the metal layer is much more rigid than the monofilament, so that the flexibility is impaired, or the metal layer is cracked by bending or the like. May occur.

  There are various known methods for coating a metal, such as an ion plating method, a sputtering method, and a vacuum evaporation method. In the present invention, the electroless plating method and the electrolytic plating method are most preferable. The reason for this is that in order to achieve an improvement in the wear resistance of the monofilament in the present invention, it is essential to coat the monofilament with a metal having a substantially uniform thickness. However, methods such as ion plating, sputtering, and vacuum deposition are methods that inherently coat one side of the substrate, and uniformly coat the metal on the surface of the monofilament as in the present invention. This is because it is difficult to apply when necessary.

  On the other hand, in the electroless plating method and the electrolytic plating method, the substrate is immersed in an electrolyte solution, and the metal is coated on the substrate by the reduction of metal ions by the action of the catalyst and the reducing agent. If the substrate is impregnated and is in contact with the electrolyte solution, the entire substrate can be coated with a metal almost uniformly.

  The type of metal to be coated in the present invention is not particularly limited as long as it is a metal that can be plated by an electroless plating method and an electrolytic plating method. However, the viewpoint of versatility, metal rigidity, environmental impact, etc. Therefore, it is desirable to coat a single layer or a plurality of layers with a single metal such as copper, nickel, silver, gold, platinum, or an alloy containing these as a main component.

  In the present invention, roughening by imparting irregularities to the monofilament is performed by treatment with plasma irradiation. At this time, in order to express the etching effect by the plasma irradiation treatment more remarkably, it is preferable to use a monofilament from which an oil agent, impurities and the like are previously removed by a conventional method before the plasma irradiation treatment. Thereafter, the whole monofilament surface is irradiated with plasma to give irregularities to the monofilament surface.

  Here, plasma means that an electric field is applied to an atmosphere filled with gas molecules under a low pressure or normal pressure, whereby free electrons existing in the gas are accelerated, and the accelerated free electrons collide with gas molecules. This means an electrically neutral atmosphere including charged particles in which gas molecules are dissociated into ions, radicals, electrons, and the like. The plasma irradiation treatment refers to a treatment for irradiating the substrate with ions or radicals having very high activity by leaving the substrate in the plasma atmosphere as described above. In this method, it is possible to irradiate the substrate with various ions and radicals depending on the type of gas molecules to be filled, and thereby various functional groups can be introduced onto the surface of the substrate. It is widely used as a surface modification technique for glass, glass, and the like.

  In the present invention, when ions, radicals, and the like are irradiated onto the substrate in this way, unevenness can be imparted to the entire monofilament surface by these etching effects.

  In the present invention, examples of the gas used for the plasma irradiation treatment include single gases such as air, oxygen, nitrogen, carbon dioxide, helium, and argon, or a mixed gas thereof, which are generally used in the plasma treatment. it can.

  The conditions for plasma irradiation treatment are different depending on the standard of the equipment used, but it cannot be said unconditionally, but under the conditions such as general pressure, frequency, voltage, electrode distance, etc. specified for each plasma irradiation equipment, It is desirable to irradiate plasma with time so that the average unevenness to be applied can be in the range of 10 nm to 1 μm. Although various types of plasma irradiation processing apparatuses are currently on the market from various manufacturers, any apparatus can be used as long as it exhibits an etching effect on the target monofilament in the present invention. There is no problem. In addition, as long as the plasma irradiation process is performed under the condition that the performance of the apparatus is sufficiently exhibited, neither the batch process nor the continuous process is particularly specified.

  In the present invention, the metal coating can be performed by an electroless plating method as described above. The conditions for this electroless plating vary greatly depending on the type and thickness of the metal to be coated, etc., but it cannot be said unconditionally. Precipitate.

  At this time, in order to more uniformly coat the metal on the monofilament surface more efficiently, it is desirable to use a monofilament surface that has been previously treated with a reducing agent or a catalyst having a function of reducing metal ions. Since the aforementioned metals generally have an autocatalytic ability, precipitation by reduction of metal ions occurs continuously, and as a result, a metal film having a substantially uniform thickness is formed on the monofilament. At this time, the immersion time of the monofilament in the electrolyte solution varies depending on the reduction rate of each metal ion, the metal ion concentration in the electrolyte solution, and the performance of the reducing agent. In the case of coating a metal by electrolytic plating, the thickness is taken into consideration, and if the thickness of the metal layer finally coated on the monofilament falls within the range of 100 nm to 2 μm, it is not particularly specified.

  As described above, after the metal is coated on the surface of the monofilament by the electroless plating method, one or more metals are coated on the surface of the metal layer by the electrolytic plating method as necessary. The purpose is to improve the wear resistance of the monofilament by coating a metal harder than the metal coated with electroless plating. However, if the thickness of this metal layer is thicker than the metal layer coated by electroless plating, the flexibility of the monofilament is impaired, and there is a concern about the metal layer being destroyed due to a decrease in handling properties or bending. The thickness of the metal layer to be coated is preferably thinner than the thickness of the metal layer to be coated by electroless plating.

  For electroplating, generally known methods can be applied as they are. The conditions for electrolytic plating vary depending on the type of metal to be coated, the metal ion concentration of the electrolyte solution, current, time, etc., but it cannot be said unconditionally. However, the thickness of the metal layer after electroplating is coated with electroless plating Although it is preferable that the thickness is smaller than the thickness of the film, it is not particularly defined.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the physical property in an Example was measured with the following method.
(1) Adhesion between monofilament and metal layer Using a small bending fatigue tester (manufactured by Kato Tech Co., Ltd.), the bent surface after the monofilament was bent 500 times under the following conditions was observed with an optical microscope. The state of peeling and the occurrence of cracks were observed. ○ when no peeling or cracking of the metal layer is observed, △ when cracking of the metal layer is observed, but no peeling of the metal layer is observed, Δ when cracking of the metal layer or peeling of the metal layer is observed Expressed as:
Bending speed: 60rpm
Bending angle: 180 °
Load: 1g
Bent part: R = 0

(2) Abrasion resistance Abrasion resistance was evaluated using a yarn abrasion tester shown in FIG. Specifically, first, a sample (monofilament) 3 having an arbitrary length is placed on a steel friction metal piece 5 (steel, 70 mm long, 20 mm wide) fixed to a friction metal piece holder 4 as shown in FIG. , Thickness 0.15 mm) and the guide pin 7. At this time, the angle of the yarn passing between the friction metal piece 5 and the guide pin 7 with respect to the yarn guide was adjusted to 50 °.
Subsequently, the sample 3 was passed through the fixed pulley 1 and both ends of the test yarn 3 were fixed. Next, after adjusting the thread tension by applying a weight of 20 g to the weight 2 with the hook, the friction metal piece holder 4 fixed to the friction metal piece holder base 8 is moved 100 times between the rails 6 having a length of 10 cm. It was made to reciprocate at a speed of / min. Then, when the fibrils were observed by visual judgment, the test was terminated, and the number of times the friction metal piece holder 4 was reciprocated was determined as the number of wear.

[Example 1]
As a monofilament, “Technora” (manufactured by Teijin Techno Products Co., Ltd., fineness: 22 dtex (diameter: 45 μm)), a copolyparaphenylene-3,4′oxydiphenylene-terephthalamide fiber, which is a para-aromatic polyamide fiber, was used. .
Next, this monofilament was heat treated at 300 ° C. for 1 minute to remove the oil agent and impurities, and then subjected to a plasma irradiation treatment for 10 minutes using the following apparatus and conditions.
Device name: Direct parallel plate electrode type atmospheric pressure plasma surface treatment device AP-T02-S350 (manufactured by Sekisui Chemical Co., Ltd.)
(Pressure: atmospheric pressure, filling gas: oxygen, frequency: 15 kHz: 15 kHz, initial output: 170 V, after amplification: 14.7 kV, clearance between electrodes: 1.5 mm)

When the monofilament after the plasma irradiation treatment was observed with a scanning electron microscope (SEM), the size of the irregularities formed on the monofilament surface was 80 nm.
Next, after impregnating the monofilament with a palladium catalyst, copper was coated by a known electroless plating method. The thickness of the coated copper was 600 nm.
Further, after that, the monofilament was coated with nickel by a known electrolytic plating method. The thickness of the coated nickel was 400 nm.

[Example 2]
In Example 1, it implemented like Example 1 except not having performed nickel coating by the electroplating method.

[Comparative Example 1]
In Example 1, it implemented like Example 1 except having made plasma irradiation time into 1 minute. At this time, the size of the irregularities formed on the monofilament surface was 5 μm.

[Comparative Example 2]
In Example 1, the coating was carried out in the same manner as in Example 1 except that the coated copper was coated to have a thickness of 3 μm, and nickel coating by electrolytic plating was not performed.

[Comparative Example 3]
In Example 1, it implemented like Example 1 except not having performed plasma irradiation processing to the technola monofilament.

[Comparative Example 4]
The technola monofilament was used as it was without plasma irradiation or metal coating.
Table 1 shows the physical properties of the obtained monofilament.

  According to the present invention, a monofilament having improved wear resistance as much as possible and free from problems of fibrillation and scum generation during weaving is provided. It can be suitably used for filter applications that are used under more severe conditions.

The schematic diagram which shows the outline of the thread | wear abrasion testing machine used when evaluating abrasion resistance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed pulley 2 Weight with hook 3 Test thread 4 Metal piece holder for friction 5 Metal piece for friction 6 Rail 7 Guide pin 8 Metal holder base for friction

Claims (4)

  It is a monofilament with a fineness of 5 to 1000 dtex, the surface of the monofilament has irregularities with a size of 10 nm to 1 μm, and the monofilament surface is coated with metal, and has excellent wear resistance Monofilament.   The monofilament excellent in wear resistance according to claim 1, wherein the thickness of the coated metal layer is 100 nm to 2 μm.   The surface of a monofilament having a fineness of 5 to 1000 dtex is subjected to plasma irradiation treatment to form irregularities with a size of 10 nm to 1 μm, and then coated with metal by an electroless plating method and / or an electrolytic plating method. Monofilament manufacturing method with excellent properties.   The method for producing a monofilament excellent in abrasion resistance according to claim 3, wherein the thickness of the coated metal layer is 100 nm to 2 µm.

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