JPH01260058A - Electrically conductive fiber - Google Patents

Abstract

PURPOSE:To provide an electrically conductive fiber having durability against friction and washing, by forming an adhesive coating film on the surface of a thermoplastic synthetic fiber and subsequently forming a resin layer containing mica coated with an electrically conductive metal and/or an electrically conductive metal compound. CONSTITUTION:An adhesive coating film comprising a polyepoxide compound and a blocked polyisocyanate is formed on the surface of a thermoplastic synthetic fiber such as polyester or polyamide fiber. On the surface is subsequently further formed a resin layer comprising a mixture of a phenolic resin with natural rubber or NBR containing mica coated with an electrically conductive metal such as nickel, cobalt, copper or silver and/or an electrically conductive metal compound such as tin oxide, antimony oxide or indium oxide to provide an electrically conductive fiber.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a colorless or white to light-colored conductive fiber, and more specifically, a conductive fiber having a thermoplastic synthetic fiber as a base and containing a conductive substance on the surface thereof. The present invention relates to conductive fibers having a resin layer formed thereon.

(Prior art) Thermoplastic synthetic fibers such as polyester fibers and polyamide fibers are generally used in large quantities for clothing and industrial purposes, but they are hydrophobic and have an electrical resistance of 10'Ω/cm or more. body, especially when used in low humidity.
It has the disadvantage that it becomes charged with static electricity when subjected to friction. Due to this charging phenomenon, dust tends to adhere to textile products when they are used.
In addition, the discharge of static electricity not only causes discomfort to the human body, but also causes serious accidents such as explosions and fires in places such as gas stations where hazardous materials are handled.

One method for solving the problem caused by electrostatic charge on hydrophobic fibers is to mix a small amount of metal fibers with hydrophobic fibers. This method requires fine denier metal fibers,
There are problems in that metal fibers are expensive and, moreover, foreign metal fibers degrade processability and product quality.

On the other hand, fibers mixed with various conductive fine particles are known as conductive fibers used for the same purpose as metal fibers. For example, fibers made of an antistatic synthetic polymer composition in which fine titanium oxide particles whose surface is coated with tin oxide are dispersed in a meltable synthetic polymer (Japanese Patent Laid-Open No. 58-39
No. 175), conductive composite fibers whose core component is a conductive thermoplastic polymer containing inorganic particles having a conductive metal oxide film (Japanese Patent Application Laid-open No. 174469/1983), whose surface is coated with tin oxide. Coated titanium oxide fine particles and/or
Or conductive composite fiber containing tin oxide fine particles (Japanese Patent Application Laid-open No. 5
6-169816). All of these conductive fibers are obtained by melt-spinning a mixture of conductive fine particles mixed and dispersed in a non-conductive synthetic polymer, but in order to exhibit sufficient conductivity,
It is necessary to disperse and contain conductive fine particles at a high concentration and to shorten the distance between the conductive fine particles. However, when the concentration of conductive fine particles in synthetic polymers increases, nozzle clogging becomes more likely to occur during melt spinning, deteriorating spinnability, increasing the frequency of disassembly and cleaning of spinning packs and nozzles, and reducing productivity. , its strength is low, and it tends to cause problems such as fuzzing and yarn breakage during the drawing process and subsequent processing steps.Furthermore, because the conductive polymer has poor malleability, the conductive layer may break, resulting in poor conductive performance. There is a problem that it is difficult to obtain high conductivity.

Furthermore, as conductive fibers that do not have the above-mentioned problems, there are known fibers in which a conductive resin layer is formed by applying a resin liquid containing fine particles of a conductive substance dispersed on the surface of an ordinary synthetic fiber.

(Problem to be Solved by the Invention) However, compared to conductive fibers in which conductive fine particles are mixed and dispersed, fibers with such a conductive resin layer formed on the surface do not easily bend or rub against the conductive resin layer. are likely to peel off and fall off, and in particular, to improve conductivity, conductive particles are added to
When added in a large amount, such as 70% by weight, the film strength of the conductive resin layer decreases significantly. As a result, a problem arises in that conductive durability against bending, friction, and even washing deteriorates.

The purpose of the present invention is to solve the above-mentioned problems, to prevent peeling and falling off of the conductive resin layer in thermoplastic synthetic fibers with a conductive resin layer formed on the surface, and to provide colorless (white to white) fibers with excellent conductive durability. An object of the present invention is to provide a light-colored conductive fiber.

(Means for Solving the Problems) As a result of various studies to achieve the above object, the present inventor formed a specific adhesive film on the surface of thermoplastic synthetic fibers, and further applied a specific conductive film on the surface of thermoplastic synthetic fibers. The inventors have discovered that by forming a conductive resin layer containing a conductive fine powder, the conductive resin layer can be prevented from falling off and its durability can be significantly improved, and the present invention has been achieved.

That is, in the present invention, an adhesive film containing a polyepoxide compound (A) and a blocked polyisocyanate compound (B) is formed on the surface of a thermoplastic synthetic fiber, and further, on the adhesive film,
This is a conductive fiber characterized by forming a resin layer containing fine mica powder whose surface is coated with a conductive metal and/or a conductive metal oxide.

The thermoplastic synthetic fibers in the present invention include fibers made of aromatic or naphthalene ring-containing linear polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; fibers made of aliphatic polyamides such as nylon 6 and nylon 66; (P-phenylene terephthalamide), poly(P-phenylene-
Examples include fibers made of aromatic polyamides such as 3,4-diphenyl ether terephthalamide). Further, the fiber form may be long fibers or short fibers, and the cross-sectional shape may be irregular or hollow.

Furthermore, the fiber surface may be roughened by chemical treatment or physical surface treatment (plasma treatment, etc.).

In order to form an adhesive film on the surface of thermoplastic synthetic fibers, a pretreatment liquid such as an emulsion or solution containing a polyepoxide compound (A) and a blocked polyisocyanate compound (B) is subjected to a conventionally known manzuke-squeezing process. A method is used in which it is applied to the fiber surface by a liquid method, a spray method, a coating method, etc., followed by drying and baking. At this time, the application of pretreatment liquid is
The treatment can be applied to fibers in any form, such as undrawn yarn, drawn yarn, spun yarn, crimped yarn, woven or knitted fabric, or nonwoven fabric. The adhesive coating used in the present invention is made of a polyepoxide compound (A
) and the blocked polyisocyanate compound (B), and sufficient durability cannot be obtained with either one alone. The polyepoxide compound (A) used in the present invention is a compound having at least two epoxy groups in one molecule in an amount of 0.62 g or more per 100 g of the compound, and examples of such polyepoxide compounds include ethylene glycol, glycerol, and sorbitol. , pentaerythritol, reaction products of polyhydric alcohols such as polyethylene glycol and halogen-containing epoxides such as epichlorohydrin, resorcinol, bis(4-hydroxyphenyl)dimethylmethane, phenol, formaldehyde resin, resorcinol.
A reaction product of polyhydric phenols such as formaldehyde resin and the above-mentioned halogen-containing epoxides, a polyepoxide compound obtained by oxidizing the unsaturated bond with peracetic acid or hydrogen peroxide, i.e., 3,4-epoxycyclohexene epoxide , 3,4-epoxycyclohexylmethyl-3
, 4-epoxycyclohexenecarboxylate, bis(3,4-epoxy-6-methyl-cyclohexymethyl)adipate, and the like. Among these,
In particular, reaction products of polyhydric alcohols and epichlorohydrin, ie, polyglycidyl ether compounds of polyhydric alcohols, are preferred because they exhibit excellent performance.

On the other hand, the blocked polyisocyanate compound (B) is an addition compound of a polyisocyanate compound and a blocking agent, and the blocking component is liberated by heating to produce an active polyisocyanate compound. Examples of the polyisocyanate compound include polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, polymethylene polyphenylisocyanate, and triphenylmethane triisocyanate, or these polyisocyanates together with trimethylolpropane and pen. NC010H>
Examples include terminal NCO group-containing polyalkylene glycol adduct polyisocyanates obtained by reacting at a molar ratio of 1. In particular, aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and polymethylene polyphenylisocyanate are preferred because they exhibit excellent performance.

Examples of blocking agents include phenols such as phenol, thiophenol, cresol, and resorcinol, tertiary alcohols such as t-butanol and L-pentanol, and aromatic secondary alcohols such as diphenylamine and xylidine.
amines, imides such as phthalic acid imide, lactams such as caprolactam and valerolactam, acetoxime,
These include oximes such as methyl ethyl kentone oxime and cyclohexane oxime, and acidic sodium sulfite.

These polyepoxide compound (A) and blocked polyisocyanate compound (B) can be used as they are, or if necessary, dissolved in a small amount of solvent and mixed with known emulsifiers such as sodium alkylbenzenesulfonate, dioctylsulfosuccinate Na salt, Emulsify or dissolve using a nonylphenol ethylene oxide adduct, etc., and dilute with a diluent such as water to obtain a pretreatment liquid. The blending weight ratio of the polyepoxide compound (A) and the blocked polyisocyanate compound (B) in the pretreatment liquid is (A)/(B) = 98
It is preferable to set it as /2 - 20/80. (A)/(B
) outside the above range, the adhesive strength of the resin layer to the thermoplastic synthetic fiber tends to decrease.

In addition, the total solids concentration of the pretreatment liquid (including the polyepoxide compound (A) and blocked polyisocyanate compound (B)) is set so that a sufficient adhesive layer is formed and the texture of the fibers is not deteriorated. , 1 to 30% by weight, preferably 3 to 20% by weight.

Further, the amount of the emulsifier, ie, the surfactant, used to form the pretreatment liquid into an emulsified dispersion is preferably 15% by weight or less, particularly 10% by weight or less, based on the total solid content of the treatment liquid. If too much of this is used, the adhesive force of the conductive resin layer to the fiber surface will decrease.

The pretreatment liquid has a coating amount of the polyeboxide compound (A) and the blocked polyisocyanate compound (B) based on the thermoplastic synthetic fibers of 0.1 to 10% by weight, particularly 0.2 to 10% by weight.
It is preferable to add it in an amount of 5% by weight. If this amount is too small, a film that enhances the adhesion of the conductive resin layer will not be formed, and if it is too large, the film will be too thick and will harden the fibers. A preferable coating amount can be easily obtained by using a pretreatment liquid having the concentration as described above.

It is desirable to dry and solidify after applying the pretreatment liquid at a temperature and heating time that do not change the strength, modulus, etc. of the thermoplastic synthetic fiber, and from the viewpoint of productivity,
It is preferable to dry at a temperature below C and heat-treat at 200 to 250°C for a short time.

The resin layer containing fine particles of a conductive substance is produced by coating a thermoplastic synthetic fiber with a solution or dispersion of a resin containing fine particles of a conductive substance dispersed therein and applying a coating of a polyepoxide compound (A) and a blocked polyisocyanate compound (B). It is formed by applying the pretreatment liquid to the formed yarn, woven or knitted fabric, nonwoven fabric, etc. in the same manner as the method of applying the pretreatment liquid, and drying and solidifying it.

In addition, as fine particles of conductive substance added to the resin layer,
Use a mica scale-like fine powder whose surface is coated with conductive metal tile d/or conductive metal M (IJI).By using mica scale-like fine powder, (1) granular fine powder such as titanium oxide is used. Compared to a powder coated with a conductive component, even if the amount of the resin layer added is small, it can effectively exhibit conductive performance. (2) By reducing the amount added, the conductive resin coating (3) The transparency of the conductive resin coating is improved, and the resin layer becomes less noticeable.

Examples of mica include natural flake mica and synthetic mica such as phlogovite, muscovite, paotite, and sericite, and the size of the fine powder The diameter is usually 10μm
The thickness is preferably 5 μm or less.

As a conductive metal to coat the surface of mica,
Examples include various conductive metals such as nickel, cobalt, copper, and silver, and alloys thereof.
It can be used in more than one layer. In addition, examples of conductive metal oxides include tin oxide, antimony oxide, indium oxide,
Various conductive metal oxides such as cadmium oxide can be mentioned, and these can be used alone or as a mixture of two or more. The appropriate amount of the conductive metal or conductive metal oxide to be coated on mica is 20 to 80% by weight.

In addition, resins include combinations of natural rubber and synthetic rubbers such as acrylonitrile-butadiene copolymer (NBR) and phenolic resins that are cosoluble therein, and resorcinol-based resins.
Combinations of formalin-rubber latex resins and true-melt polyester adhesives with isocyanates, polyurethane polymers, urea, melamine, aminoalkyl, aminoaryltriazine, and other amino compounds (both one type and formaldehyde). Alcohol-modified amino resins obtained by modifying condensates with alcohols such as butanol and isopropanol by conventionally known methods, vinyl polymers obtained by partially oxidizing vinyl chloride vinyl acetate copolymers, acrinic acid esters or methacrylic acid esters. Vinyl polymers such as acrylic polymers made by copolymerizing styrene and reactive monomers such as methylol acrylamide, glycylacrylate, and hydroxyethyl methacrylate, and polyvinyl acecoolic polymers such as polyvinyl butyral are flexible and flexible. Breaking elongation 10-500%
It is preferably used because it forms a film of other than this,
Epoxy resins, alkyd resins, melamine resins, urea resins, etc. are also used.

In particular, it is preferable to use NBR in combination with a phenolic resin that is co-soluble therein since it has excellent adhesion to the film formed from the polyepoxide compound (A) and the blocked polyisocyanate compound (B).

The mixing ratio of mica fine powder whose surface is coated with conductive metal and/or conductive metal oxide to resin is 3.
It is preferably 0 to 80% by weight, particularly 40 to 60% by weight. Within this range, it is possible to easily form a conductive resin layer that has excellent adhesion and film strength and has a fiber electrical resistance of 10 9 Ω/cm or less. On the other hand, if the proportion of the conductive substance is small, the electrical resistance of the conductive resin layer will increase, making it difficult to reduce the electrical resistance of the fiber to 109Ω/cm or less, and if the proportion of the conductive substance is too high. As a result, the adhesion and film strength of the conductive resin layer decrease, resulting in poor durability.

The resin liquid containing fine particles of a conductive substance dispersed in the proportions described above may include alcohols such as butanol, M
A solution of the above-mentioned resin is prepared using a solvent such as a carbon such as EK, an aromatic hydrocarbon such as toluene, ethyl cellosolve, etc. alone or in combination, and a conductive substance such as the above-mentioned conductive substance is added to this solution. Appropriate viscosity with fine particles dispersed in it,
Further, it is preferable to use a resin having an appropriate viscosity and containing a curing accelerator such as a phosphoric acid monoalkyl ester, a plasticizer, or other polymer as appropriate.

This viscosity can be determined by applying a resin liquid using a conventionally known method.
It is preferable that the viscosity is such that a coating amount that forms a conductive resin layer with a thickness of 5 to 15 μm (7) can be easily obtained.

Once the resin liquid is applied, it is dried and solidified in the same manner as the pretreatment liquid, thereby forming a conductive resin layer. Drying and solidification are carried out by passing the thread, etc. to which the resin liquid has been applied, through a hot air oven at 70 to 180"C to remove the solvent, and then passing it through a hot air oven at 130 to 240°C to harden the resin. This preferably maintains the strength, modulus, etc. of the polyester fiber, and reduces the electrical resistance to 104 to 109 Ω/cm.
A conductive fiber with excellent durability can be obtained.

The conductive fibers of the present invention include staples, filament yarns,
It can be used 100% in processed yarns, woven and knitted fabrics, etc., or it can be mixed with other insulating fibers or threads to prevent static electricity.

(Function) In the present invention, by using mica whose surface is coated with a conductive metal and/or conductive metal oxide, sufficient conductive performance is exhibited even if the amount added to the resin layer is reduced. This is thought to be due to the following reasons.

That is, in the process of applying a resin containing a conductive substance based on flaky mica to the fiber surface, there is a high probability that the planes of the flaky mica will be aligned parallel to the applied surface, and as a result, fine mica powder The comrades are brought closer together, the distance between them becomes narrower, and the conductive performance is improved.

(Examples) Hereinafter, the present invention will be further explained by Examples and Comparative Examples. In the Examples and Comparative Examples, the electrical resistance was measured using an FM multi-tester L-19-B model and an automatic insulation resistance meter L-68 model manufactured by Yokogawa Electric Corporation. .61, number of teeth 20, rotation speed 120 rpm
The test was carried out by hanging a load of 0°36 g/de on the tip of a nylon gear.

Examples 1 to 5, Comparative Examples 1 to 4 A 30% by weight aqueous solution of dioctyl sulfosuccinate Na salt (Dai-Kogyo Seiyaku Co., Ltd.) as a surfactant was added to 60 g of Trubeetle polyglycidyl ether (Denacol EX-611, manufactured by Nagase Sangyo Co., Ltd.). Neocol SW-30) 40g
Add to dissolve uniformly. Add this to 740 g of water with vigorous stirring, then add 160 g of a 25% emulsified dispersion of ε-caprolactam block of 4゜4'-diphenylmethane diisocyanate (S5-3 manufactured by Meisei Kagaku ■) and mix uniformly. and obtain a pretreatment solution.

After immersing a 20 denier polyethylene terephthalate monofilament in this pretreatment solution and pulling it up, the
It was dried at 230°C for 2 minutes and then heat treated at 230°C for 1 minute. The amount of pretreatment agent fixed was 0.25% by weight. A plurality of the obtained monofilaments were passed through a resin liquid having the composition shown below in an aligned state with intervals, and then passed through a slit to adjust the adhesion thickness of the resin liquid, and then heated at 130°.
After drying in a hot air dryer at 200°C and solidifying the resin by introducing it into an air bath at 200"C, the plurality of monofilaments are rolled up in a winder to determine the thickness of the conductive coating on the constituent filaments. A conductive multifilament having an average diameter of 2.5 μm was obtained.The performance of this yarn is shown in Table 1.

Table 1 Comparative Examples 5 to 7 In the example, when the treatment with the pretreatment liquid was not performed (Comparative Example 5), 60 g of Bunacol 6 was used as the pretreatment liquid.
The conductivity obtained when using a solution containing only 11 and 40 g of Neocol 5W-30 (Comparative Example 6) and when using a solution containing only 160 g of S-3 as a pretreatment solution (Comparative Example 7) The performance of the multifilament yarn was measured and the results are shown in Table 2.

Table 2 As shown in Tables 1 and 2, the conductive fibers of the present invention exhibit sufficient conductivity even when the amount of the conductive substance added is reduced. Therefore, by reducing the amount of the conductive substance added, it is possible to prevent the adhesion and film strength of the conductive resin layer from decreasing and provide a conductive fiber with excellent durability.

(Effects of the Invention) The conductive fiber of the present invention exhibits an effect that the conductivity is extremely durable against friction and washing.

Claims (1)

[Claims] 1. Polyepoxide compound (
An adhesive film containing A) and a blocked polyisocyanate compound (B) is formed, and further thereon, a resin layer containing mica fine powder whose surface is coated with a conductive metal and/or a conductive metal oxide. A conductive fiber characterized by forming.