JPH0327142A - Extremely fine filament bundle - Google Patents

Abstract

PURPOSE:To obtain the fiber bundle which is free from fluffs, having no fiber having cut face-like section on its surface, by bundling a plurality of thermoplastic ultra-fine fibers which have round cross section and undefined length in almost parallel and binding them partially. CONSTITUTION:The objective fiber bundle is a bundle of ultrafine filaments made of a synthetic resin, said filaments shows equivalent properties to those of single filament, have almost round cross section, undefined length and less 200mu diameter so that the filaments are extended in almost parallel and bundled, in which the ultrafine filaments are partially adhered to one another. The fiber bundle is preferably obtained by melt-kneading a thermoplastic resin, water and an agent for helping water dispersing in the resin, and extruding under pressure through an orifice into a bundle of a plurality of ultrafine filaments extending in almost parallel. It is preferred that a single shaft extruder is preferably used in filament formation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to ultrafine fiber bundles. More specifically, the present invention relates to a new shape of ultrafine fiber bundle.

[Conventional technology]

Various proposals have been made regarding bundles of ultrafine fibers having a diameter of several hundred microns or less and techniques for producing them. For example, ultra-fine fibers are manufactured using a super draw method (such as JP-B No. 28-617), a flash spinning method (such as JP-B No. 35-11851), or a jet spinning method, and then a large number of ultra-fine fibers are bundled using a binder. method, or method of mechanically twisting and converging (in the case of ultrafine fibers,
This method is practically difficult). However, when using the super draw method, the types of resins that can be used are limited and a special stretching process is required after spinning, resulting in large-scale equipment. Although the flash spinning method can be applied to many types of resin, it can only produce short fibers, making it difficult to make continuous fibers.

Furthermore, since the solvent is scattered during the flashing step, this is not a preferable method from the viewpoint of safety and working environment. Jet spinning requires a specially shaped spinneret and has the same problems as flash spinning. Above all, these methods require special secondary processing to produce fiber bundles, but secondary processing of ultrafine fibers is extremely difficult due to their weak fiber strength.

For this reason, we developed a technology that uses two types of resins to spin fibers with an island structure, and then extracts and removes the resins, leaving behind ultrafine fibers of the islands, to produce fiber bundles. Force Z has been proposed as a bolima blend fiber dissolution method or a polymer mutual array fiber dissolution method. However, in many polymer blend fiber melting methods, the longitudinal length of the resin forming the islands is short, making it difficult to form continuous fibers. Among them, as seen in Japanese Patent Publication No. 44-21167, an attempt to make continuous fibers by this method has been proposed.C1 The resulting ultrafine fiber bundle is a complex network-like tangle and sag. . On the other hand, the latter polymer mutual array fiber dissolution method (
Since Tenshimakaibun is long and continuous in the vertical direction, it is possible to manufacture bundles of continuous ultrafine fibers, and the resulting fiber bundles also have multiple ultrafine fibers that are arranged independently and in parallel. A special structure is required for the Kerr spinneret, which results in a complicated and expensive device. Moreover, in all of these methods, ultrafine fiber bundles can only be obtained after a post-processing step is performed in which the sea fraction is extracted.

[Problem to be solved by the invention]

Against this background, the inventors of the present invention have conducted intensive research to develop a technology to produce ultrafine fiber bundles without requiring special secondary processing or post-processing processes, and as a result, they have found a technology that would be unimaginable with conventional common sense. By perfecting the new spinning technology, that is, the spinning technology in which the fiber itself spun from a single spinning hole is already a bundle of ultrafine fibers, the ultrafine fiber bundle of the present invention was obtained. It is.

By the way, conventional examples disclosing fiber bundles or related conventional examples include Utility Model Publication No. 50-30438 and Japanese Patent Publication No. 1983-46-
No. 32458 and Japanese Unexamined Patent Application Publication No. 46-3906 are known.

Utility Model Publication No. 50-30438 describes split fibers of a linear material made of a mixed resin of polyolefin resin and polyvinyl alcohol resin. (Page 2 of the publication, lines 15 to 16 on the right side).

Further, Japanese Patent Publication No. 46-32458 describes a fibrous material fibrillated by high-speed airflow, and there is a description that it is made into a sheet, but there is no description of the ultrafine fiber bundle itself.

Sara & He JP-A-46-3906 describes the production of polyolefin fibers by mechanically refiling a fibrous gel containing fibers with a diameter of 1 to 20 μ and microscopic fibers of 1 μ or less from an olefin. A method is described (bottom left and right columns of page 2 of the publication). Here, fibrous gel is defined as "the O-fiber structure of fibrous polyolefin defining a network structure that interconnects capillary spaces filled with a reaction medium" (Page 3 of the publication). Upper left column, row 9 to 1
2 lines, the characters in the ○ part are illegible). Moreover, refiling means "applying a shearing force to the fibrous gel" (page 9, lower right column, lines 12 to 14 of the publication). Therefore, the fibers obtained are, for example, 10
-15 mm, or less than 0.05 mm (Line 1 to Line 3, upper right column, page 7 of the publication). In addition, various properties of the obtained fibers are described in this publication, which are different from the properties of the ultrafine fiber bundle to be obtained in the present application.

First aspect of the present invention It is an object of the present invention to provide an ultrafine fiber bundle that has no cut surface on the surface of each fiber and is substantially free of fluff, unlike such conventional fibers or fiber bundles. shall be.

[Means to solve the problem]

That is, the present invention has a substantially circular cross-sectional shape, a substantially indefinite length, and a diameter of 200 μm, which is substantially equivalent to a single fiber formed singly.
The following microfine fiber bundles of thermoplastic resin microfibers are bundled in a substantially parallel state, and the microfine fibers constituting the fiber bundles are partially bonded to each other. It is an ultra-fine fiber bundle characterized by

A suitable method for producing this ultrafine fiber bundle is to melt-knead a thermoplastic resin, water, and an auxiliary agent that assists in dispersing the water into the thermoplastic resin, and then spin it through an orifice. A method for producing an ultrafine fiber bundle is mentioned in which a fiber bundle in which a large number of ultrafine fibers having a diameter of 200 μm or less are bundled in a substantially parallel state is spun from a single orifice hole.

[Effect]

The ultrafine fiber bundle of the present invention will be explained below according to its manufacturing method.

Thermoplastic resin> The thermoplastic resin that is the raw material of the present invention may be any resin, whether crystalline or non-crystalline, as long as it is water-insoluble and can be made into fibers, such as high pressure low density polyethylene, medium low pressure low density polyethylene, Density polyethylene, high density polyethylene, ultra high molecular weight polyethylene, polypropylene, ultra high molecular weight polypropylene, poly l-butene, poly 3-methyl-l-butene, poly 4-methyl-1-bentene or ethylene,
Propylene, l-butene, 3-methyl-1-butene,
Random or block copolymerization of σ-olefins such as l-bentene, 4-methyl-1-bentene, 1-hexene, 1-decene, etc. Ethylene-butadiene copolymer, ethylene-nitylidene-norbornene copolymer, nitylene- Brobylene/butadiene tertiary copolymerization book Nitilene/
Brobylene/dicyclobentadiene ternary copolymerization book. Ethylene/propylene/l,5-hexadiene ternary copolymer imitation. Conjugated or non-conjugated with two or more a-olefins such as ethylene/propylene/ethylidene norbornene ternary copolymer. Copolymer with conjugated diene, ethylene/acrylic acid copolymer book
Ethylene/vinyl acetate copolymerization book Ethylene/vinyl alcohol copolymerization book Ethylene/vinyl compound copolymerization book such as ethylene/vinyl chloride copolymer Book Polystyrene, acrylonitrile/styrene copolymerization book Acrylonitrile/butadiene/styrene copolymerization book Methyl methacrylate/ Styrene copolymerization book Styrenic resins such as α-methylstyrene/styrene copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl chloride/vinylidene chloride copolymerization book Vinyl polymerization book such as polymethyl acrylate, polymethyl methacrylate, etc. Nylon 6, nylon 66, nylon 6 1 0
, polyamides such as nylon 11 and nylon 12, thermoplastic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyphenylene oxide, borisulfone, polyphenylene sulfide, polyether ether ketone, and mixtures thereof.

The present invention has a car that can use the various resins listed above.In particular, a major feature is that low-density polyethylene and ultra-high molecular weight polyethylene, which were conventionally difficult to make into ultra-fine fibers, can be used in the same way as other resins. .

Auxiliary agent> Auxiliary agent IL which is another precept of the present invention When a thermoplastic resin and water are mixed, water gradually disperses into the thermoplastic resin and causes a phase inversion, resulting in Its main function is to produce an aqueous dispersion in which the continuous phase is water, such as a thermoplastic resin dispersed in water. It is thought that the occurrence of such a phenomenon by melt-kneading causes the production of ultrafine fiber bundles in bulk. That is, by simply melt-kneading a thermoplastic resin and water without using an auxiliary agent, an ultrafine fiber bundle cannot be produced, and therefore the object of the present invention cannot be achieved.

The general concept of an auxiliary agent that exhibits this type of action is that it has both a wood parent group and a lipophilic group in its molecule, and more specifically, it is one of the following compounds, either alone or in combination of two or more. used.

(A) Water-swellable or water-soluble thermoplastic resin (B) Slightly water-soluble or water-insoluble thermoplastic resin modified with unsaturated carboxylic acids (C) Surfactant (used in combination with A and/or B) ) (D) Organic solvent (used in combination with A and/or B) (E) Others (used in combination with A and/or B) These will be explained in detail below.

A is a substance that swells or dissolves (infinite swelling) in water, and includes polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose or its sodium salt, polyacrylic acid,
Examples include sodium polyacrylate and polyacrylic acid amide.

Among these, polyvinyl alcohol especially has a degree of saponification of 6.
Partially saponified polyvinyl alcohols from 5 to 98% and even from 80 to 97% are advantageous.

When these auxiliary agents are kneaded together with the aforementioned thermoplastic resin and water, the auxiliary agents are first uniformly kneaded into the thermoplastic resin, and then the auxiliary agents are swollen by the water and the thermoplastic resin is divided. It is thought that the water further penetrates into the interior, swells the auxiliary agent present inside, and promotes the division of the thermoplastic resin, ultimately giving an aqueous dispersion in which the thermoplastic resin is finely divided by water. .

The features of this type of auxiliary agent are that the types of thermoplastic resins that can be used are fewer than those of the auxiliary agents described below, and that if the manufactured ultrafine fiber bundle is left alone, the ultrafine fibers will gradually break down over time. The result is a fiber bundle that looks like it is firmly adhered, and a fiber bundle that also has hydrophilic properties.

It is a product obtained by graft copolymerization or block copolymerization of unsaturated carboxylic acids with a poorly water-soluble or water-insoluble resin, or a product obtained by random copolymerization into the resin, and has particularly good compatibility with the thermoplastic resin used as the fiber raw material. Furthermore, those with low melt viscosity are preferred.

The index that serves as a guideline for compatibility is the solubility parameter (Sp value), and the difference in Sp value must be within 2 (Cal/cm') 2 or more, especially 1 (Ca 1 /cm.) l·2. is preferable.The Sp value is 1/ of the cohesive energy density.
It is a value defined as a square value, and the contribution value Vi of the atomic group to the molar volume and the cohesive energy En of the atomic group are expressed as D.
W. Van. Klevelen ”Propert
ies of Polymers (Elsevie
r, 1972) can be calculated from the formula using the values described. Further, examples of the material having a low melt viscosity include wax-like materials having a small molecular weight.

Although this modified resin has a carboxy group derived from an unsaturated carboxylic acid or a derivative group thereof, and is therefore hydrophilic, it does not swell in water because the base resin is poorly water-soluble or water-insoluble.

Further, there are unsaturated carboxylic acid units +3 unsaturated carboxylic acids or esters thereof in modified resins, or unsaturated carboxylic acid salts obtained by neutralizing or saponifying these. Among them, unsaturated carboxylic acid O sulfate has a concentration of O. 1-5
One containing millimole equivalents, particularly 0.2 to 4 millimole equivalents, is preferred.

The modified resin is a copolymerization of the monomers constituting the poorly water-soluble or water-insoluble thermoplastic resin mentioned above and unsaturated carboxylic acids, and the unsaturated carboxylic acids include (meth)acrylic acid, maleic acid, and fumaric acid. acids, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid (endocysubicyclo [2
, 2,1] hept-5-ene-2,3-dicarboxylic acid)
, unsaturated carboxylic acids or anhydrides thereof such as maleic anhydride and citraconic anhydride, methyl of the above unsaturated carboxylic acids,
Examples include monoesters such as ethyl and probyl, nister compounds such as diesters, and unsaturated carboxylates such as alkali metal salts, alkaline earth metal salts, and ammonia salts. Of course, it will be obvious to those skilled in the art that instead of copolymerizing a plurality of monomer components, the above-mentioned unsaturated carboxylic acids may be graft-polymerized or block-polymerized to a thermoplastic resin, such as an olefin resin.

As mentioned above, a preferred embodiment of this modified resin contains 0.10 unsaturated carboxylic acid salts per 1 g of polymer (calculated as 10101 groups).
In order to produce the modified resin of this embodiment, a thermoplastic resin that has been modified in advance with an unsaturated carboxylic acid, its anhydride, or its ester is treated with a basic substance, that is, an alkali. Earth Kinho Substances that act as bases in water such as ammonia and amines, alkali metal oxides, hydroxides, weak acid salts, hydrides, alkaline earth metal oxides, hydroxides, weak acid salts, and hydrides , alkoxy of these metals. An example of this method is to saponify a neutralized sentence by using Specific examples of such basic substances are shown below.

(1) Examples of alkali metals include sodium, potassium, and alkaline earth metals such as calcium, strontium, and barium; (2) Examples of amines include inorganic amines such as hydroxylamine and hydrazine;
Methylamine, ethylamine, ethanolamine, cyclohexylamine, (3) Oxidation of alkali metals and alkaline earth metals. Examples of hydroxides and hydrides include sodium oxide, sodium peroxide, potassium oxide, potassium peroxide, and calcium oxide. , stocontium oxide, barium oxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium hydride, potassium hydride, calcium hydride, (4) Alkali metals and alkaline earth metals Sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, calcium hydrogen carbonate, sodium acetate, potassium acetate, calcium acetate; Examples of the ammonium compounds include tetramethylammonium hydroxide, hydrazine hydrate, and the like.

As the carboxylic acid group or carboxylic acid ester group neutralized or saponified with a basic substance, alkali metal carboxylates such as sodium carboxylate and potassium carboxylate, ammonium carboxylate are suitable, and potassium carboxylate is especially preferred. preferable.

The direct surfactant is not used alone as an auxiliary agent, but is used in combination with A and/or B above. The surfactant to be used may be an anionic surfactant, a cationic surfactant, a nonionic surfactant, or a zwitterionic surfactant. and/or together with B, the diameter is 100μ
The following is suitable as anionic surfactant because it can produce ultra-fine fibers of approximately less than 50μ.In addition to those that are in the form of anionic surfactant from the beginning, It also includes organic compounds that react with basic substances to eventually become anionic surfactants. In other words, the thermoplastic resin and anion are obtained by melt-kneading the thermoplastic resin, A and/or B, and the organic compound, and then adding a basic substance and continuing the melt-kneading to convert the organic compound into an anionic surfactant. The surfactant is well mixed and ultrafine fibers with a smaller diameter are obtained.

Any organic compound may be used as long as it reacts with a basic substance to become an anionic surfactant.
Preferred examples include primary higher fatty acids, secondary higher fatty fish, primary higher alcohol sulfuric esters, secondary higher alcohol sulfuric esters, IML higher alkyl sulfonic acids, secondary higher alkyl sulfonic acids, and higher alkyl disulfones. acids, sulfonated higher fatty acids, higher fatty acid sulfuric esters, higher fatty acid ester sulfonic acids, higher alcohol ether sulfonic acids, higher alcohol ether sulfonic acids, alkylolated sulfuric esters of higher fatty acid amides,
Examples include alkylbenzenesulfonic acid, alkylphenolsulfonic acid, alkylnaphthalenesulfonic acid, and alkylbenzimidazolesulfonic acid. Among these, higher fatty acids, particularly saturated or unsaturated higher fatty acids having 10 to 20 carbon atoms, are particularly preferred; more specifically, cabric acid, undecanoic acid, lauric acid, myristic acid, and palmitic acid. acids, saturated fatty acids such as margaric acid, stearic acid, arachidic acid,
Examples include unsaturated fatty acids such as lindelic acid, tuzic acid, petroselic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, and mixtures thereof; saturated fatty acids are particularly preferred.

Specific examples of surfactants include 8-turn anionic surfactants and nonionic surfactants. The former include primary higher fatty acid salts, secondary higher fatty acid salts, primary higher alcohol sulfate ester salts, Secondary higher alcohol sulfate ester salt, primary higher alkyl sulfonate, secondary higher alkyl sulfonate, higher alkyl disulfonate, sulfonated higher fatty acid salt, higher fatty acid ester sulfonate, sulfuric acid of higher alcohol ether ester salt,
Sulfonates of higher alcohol ethers Alkylolated sulfate ester salts of higher fatty acid amides, alkylbenzene sulfonates, alkylphenol sulfonates, alkylnaphthalene sulfonates, alkylbenzimidazole sulfonates Mine The latter are alkyl ethers, alkyl allyl ethers, Alkylthioether, alkyl ester, sorbitan monoalkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkyl amide, polyoxyethylene polyoxypropylene, bentaerythritol ester, saccharose ester, fatty acid ethanolamide, methicolamide, oxymethyl ethanol Amides and the like can be mentioned.

Of course, anionic and nonionic surfactants other than those exemplified here may also be used.Cationic surfactants and amphoteric ionic surfactants not exemplified here may also be used.More detailed examples of these surfactants can be found, for example, in Hiroshi Horiguchi. It is disclosed in ``Gokai Surfactant'' (1968, Sankyo Publishing).

Among the above surfactants, if one converted into an anionic surfactant by addition treatment with a basic substance is used, the produced ultrafine fiber exhibits alkaline properties, that is, pH 9 or higher. In addition, nonionic surfactants result in ultrafine fiber bundles exhibiting properties of approximately neutral pH. In the case of nonionic surfactants, those with an HLB value of 13 to 19 are preferred because they produce ultrafine fibers with a smaller diameter. HLB value is Griffin
It is derived from the formula, and details can be found in the Surfactant Handbook (written by Nishiichiro et al., Sangyo Tosho, 1972), 3.07-310.
It is disclosed on page.

10Σ and 1'1 Organic solvents have a high molecular weight or narrow molecular weight distribution, high melt viscosity, and are used when making ultrafine fiber bundles from thermoplastic resins that are difficult to melt and knead. Therefore, melt 70 ley }
(MFR, ASTV D 1238) is Ig/10
The effect is remarkable when applied to a resin with no grooves, but of course, if the melt viscosity is small, that is, the MFR is
It can also be applied to resins with g/10 min or more.

Furthermore, organic solvents are not used alone, but are
and/or B is used in combination with C if necessary.

Examples of such organic solvents are benzene, toluene,
xylene, styrene,. Aromatic hydrocarbon milks such as α-methylstyrene and vinylbenzene, aliphatic hydrocarbon milks such as hexane and heptane, and halogenated hydrocarbons such as trichloroethylene.

- Riro i body 1 In addition to those listed above in A-D, petroleum resins, rosin, asphalt, etc. may be used in combination with A and/or B, as well as C and - D, if necessary. Preferably, it is combined with a swellable or water-soluble resin.

Preferred embodiments of the auxiliary agent> There are various ways to use the auxiliary agent. For example, use of A or B alone, combination of A and B, combination of A and/or B and C, A
and/or a combination of B and D, a combination of A and/or B, C, and D, a combination of A and E, and the like. More preferably, when the fiber diameter is made relatively thick (approximately 50μ or more), a neutralized or saponified modified resin (B) is used, and when the fiber diameter is made thin (approximately less than 50μ), a neutralized or saponified modified resin (B) is used. When using B) and a surfactant (C), or especially when aiming at neutral ultra-fine fibers, use (C) of the above combinations.
When selecting a nonionic surfactant as a nonionic surfactant or aiming for ultrafine fibers made of resin with a high melt viscosity, neutralized or saponified modified resin (B), surfactant (C), and organic solvent (
D) is used, or furthermore, when the fiber bundle itself is to be firmly solidified, a water-soluble resin (A) is used.

The amount of the auxiliary agent used varies depending on the type of thermoplastic resin to be made into ultrafine fiber bundles and the type of auxiliary agent. Parts by weight, particularly 5 to 20 parts by weight (however, the total of both is 100 parts by weight). In particular, when using a thermoplastic resin, a neutralized or saponified modified resin, and a surfactant as a preferred embodiment of the present invention, each of 75 to 98
Weight pulse 1-20 weight paper 1-5 parts by weight (total is lOO
Particularly, 80 to 95 parts by weight, 3 to 16 parts by weight, and 2 to 4 parts by weight are mixed.

Furthermore, in the case where a water-swellable or water-soluble thermoplastic resin is used in place of the surfactant in this combination, the ratio may be approximately the same as above.

Addition of water〉 Amount of water added to the system consisting of thermoplastic resin and auxiliary agent (
(ix) 3 per 100 parts by weight of the thermoplastic resin and auxiliary agent
~20 parts by weight, especially 5 to 15 parts by weight. When the amount of water is within this range, the desired thermoplastic resin can be formed into ultrafine fiber bundles.

Water can be added in various ways, including a method in which water is added in advance together with the thermoplastic resin and an auxiliary agent before melt mixing, and a method in which water is gradually added during melt mixing.

Water to be added 14 In addition to adding pure water, for example, when a surfactant is used as an auxiliary agent, there is a method of adding it as an aqueous solution and adding the surfactant and water together.

Production of ultrafine fiber bundles> To produce ultrafine fiber bundles, the thermoplastic resin, auxiliary agent, and water are melt-kneaded and then spun from an orifice such as a spinning nozzle. It can be produced by spinning a fiber bundle in which a large number of ultrafine fibers of 200 μm or less are bundled in a substantially parallel state.

The following points should be noted at this time.

■ At first, the melt mixture is in the form of water dispersed in the thermoplastic resin (W/O type), but as the melt mixture continues, water becomes a continuous phase due to the action of the auxiliary agent, that is, the water becomes a continuous phase. The thermoplastic resin is dispersed inside (○/W type). When spinning from an orifice, from the above W/O type to O
/Do this just before the W-type phase inversion occurs.

■ Spinning is performed by passing through an orifice.

■ Spinning under conditions where water is not substantially flashed.

To explain in detail the meaning of (2) above, the water added to the system is gradually sucked into the molten resin by the shearing force caused by mixing and the action of the auxiliary agent, forming a W/O type dispersion. . If shearing force is continued to be applied, this time, even though the amount of water dispersed is small (at most 3 to 20 parts by weight per 100 parts by weight of the thermoplastic resin and auxiliary agent). Water becomes a continuous phase and the phase inverts to O/W type. This W/O to O
/W is on the verge of a phase change (incoming water does not form a completely continuous phase (water combined three-dimensionally), but continues in a certain direction (water combined two-dimensionally). Therefore, under the latter condition, the thermoplastic resin is considered to be not particles but a fibrous resin phase that is continuously connected in one direction.Under such conditions, spinning By doing so, the fiber bundle of the present invention can be spun, and even if the fiber bundle of the W/0 type or completely 07W type is spun, not only the ultrafine fiber bundle of the present invention cannot be produced, but it may not even become fibrous. Therefore, the term "just before phase inversion" as used herein refers to the range in which a fiber bundle such as that of the present invention can be spun.

Regarding (2), the meaning of spinning by passing through an orifice is that the resin on the verge of phase inversion becomes fibrous with water as the boundary phase, but as it is, many of these fibrous resins are randomly oriented. Since it is a material that has a fibrous structure, it exhibits the effect of aligning the fibrous resin by applying orientation in a certain direction. This differs from the conventional melt spinning method (round). The fibers come out as a bundle of fibers that are bundled approximately parallel to the direction in which they are extruded.

Regarding (2), when the molten blend is finally spun to the outside, the water contained in the molten mixture should not be substantially flannoshed, that is, the sudden extrusion that causes the water to flash as in the conventional flash spinning method should be stopped. It is. If the molten mixture is rapidly extruded as in the flash spinning method or extruded with a differential pressure applied, a fiber bundle cannot be obtained. More specifically, there is a method in which spinning is performed under pressure, or a method in which the pressure in a melt-kneading machine is made approximately the same as atmospheric pressure and spinning is performed under atmospheric pressure. The moisture content of the fiber bundle obtained by spinning under such conditions is 17% by weight or less.

As a specific device for producing the ultrafine fiber bundle of the present invention, there is, for example, a method of extruding it using a single-screw or twin-screw extruder. In the case of a twin-screw extruder, the shearing force is too strong and it is difficult to reproduce a state on the verge of phase inversion, so it is better to weaken the shearing force by making the screw groove into a special shape. Generally, a single-screw extruder is preferred because it has a weak shearing force and can easily reproduce a state on the verge of phase inversion.

The shape of the orifice may be a T-die used in forming a film in addition to a normal spinneret.

Properties of the ultrafine fiber bundle> The properties of the ultrafine fiber bundle produced by the method described above are substantially the same as a single fiber formed singly, with a substantially circular cross-sectional shape and a substantially indefinite diameter. 200μ or less, mostly 10
An ultrafine fiber bundle in which a large number of thermoplastic resin ultrafine fibers of 0μ or less are bundled in a substantially parallel state without being twisted, and the ultrafine fibers that make up the fiber bundle are partially adhered to each other. It means that a place exists. Therefore, when this fiber bundle is unraveled, it appears to be fibrous at first glance because of the adhesive parts.

More specifically, photographs showing the fiber shape of an example of the ultrafine fiber bundle of the present invention are shown in FIGS. 1 to 4. FIG. 1 is a photograph (2x magnification) showing the fiber bundle of the present invention. It can be seen that the fiber bundle is strong and not twisted at all. FIG. 2 (5x magnification) and FIG. 3 (5x magnification) are photographs showing the fiber bundle in an unraveled state, and it can be seen that the fiber bundle is made up of a large number of ultra-fine fibers bundled approximately in parallel.

FIG. 4 is a partially enlarged photograph (40x magnification) of the separated fiber bundle, and it can be seen that the ultrafine fibers are partially adhered to each other.

The fact that the fibers constituting the fiber bundle of the present invention are substantially equivalent to single fibers formed singly means that each constituent fiber is The fibers have a shape that is substantially the same as if they had been formed individually (for example, by melt-spinning), and although the thickness of each fiber is not necessarily the same, there is no branching other than due to the adhesion of the fibers to each other. This means that there is substantially no separation, and the fiber bundle of the present invention is composed of these fibers assembled together. Therefore, the shape is different from physically splitting a melted or shaped belt-like or string-like molded product, and there is no cut surface on the surface of each fiber, and there is substantially no fuzz.

〔Example〕

The present invention will be explained below using preferred examples, but the content of the present invention is not limited to these examples unless otherwise specified.

[Example 1]

Vented single-screw extruder 8 with a water cooling mechanism at the tip and liquid inlets in the first compression zone and first metering zone! Low-density polyethylene (manufactured by Mitsui Petrochemical Industries, Ltd., product name: Mirason FL-60 MPR=
7 0 g 7 1 0 min density = 0.915 g/C
m3Sp value = 7. 80 (Cal/cm3)”
2) 9 3 parts by weight and maleic anhydride grafted polyethylene 0 I1 (maleic anhydride content 3.3% by weight, 1010-groups =
0.67 mmol 1 equivalent/g, Mw=2700 Density=0
．． 94g/cm”, Sp value 8.06 (Cal/Cm3)
I/2) 5 parts by weight of the mixture are continuously fed at a rate of 98 parts by weight/hour and plasticized at 140°C. Next, an anionic surfactant (manufactured by Kao Soap Co., Ltd., trade name Emulgen ■430) is poured into the liquid inlet provided in the first measuring zone of the extruder.
Polyoxyethylene oleyl ether HLB=16.2
) was pressurized with a plunger pump and continuously supplied at a rate of 12 parts by weight/hour (pressure 1 2
After passing through a 100 mesh screen at an extrusion temperature of 95°C, it is continuously extruded from a nozzle with a diameter of 3 mm. It was measured to be 9%, t4.Next, the fiber bundle was spread out and the single fibers were observed under a microscope, and it was found that there were some parts where the single fibers were partially adhered to each other.9 The thickness of the single fibers was approximately 25 to 50 μm. [Examples 2 to 9] The results are shown in Table 1 in the same manner as in Example 1 using the proportions shown in Table 1.
(This page, hereafter in the margin) [Example 1O] From the hopper of the same extruder used in Example 1, low-density polyethylene (manufactured by Mitsui Petrochemical Industries, Ltd., trade name)
Mirason FL-60 MFR=70g/10min Density=0. 9 1 5 g/cm3Sp value=7.80
(Cal/Cm3) I/2) and maleic anhydride grafted polyethylene (maleic anhydride content 3
3% by weight, ○l1-C-〇1 group=0.67mmol1 equivalent/g, Mw=
270 0, density = 0. 9 4 g/cm'
, a mixture of Sp value 8.06 (Cal/cm3)''2) and stearic acid in a weight ratio of 92/5/3 (weight ratio)
It is continuously fed at a rate of 0 parts by weight/hour and plasticized at 140°C. Next, a 9.8% potassium hydroxide aqueous solution was pressurized with a plunger pump and continuously supplied at a rate of 8 parts by weight/hour from the liquid inlet provided in the first metering zone of the extruder (pressure 120 kg/cm2G) Extrusion temperature 9
The product extruded at 5°C in the same manner as in Example 1 was a white fiber bundle in which single fibers were bunched in a substantially parallel state, and the moisture content was measured to be 7%. When I investigated the thickness of the single fiber, it was approximately 25 ~
When 5 parts by weight of fiber bundles were added to 100 parts by weight of water and the pH of the water layer was measured, it was found to be 10.
5 and 9 [Examples 11-16] Table 2 shows the results of the same procedure as in Example 10 using the groups shown in Table 1 at certain ratios.

(This page, the following margins) [Example 17] Example 1 was produced using Hosopar, the same extruder used in Example 1.
The same ethylene/1-butene copolymer resin used in 6 was added to 9.
It is continuously fed at a rate of 7 parts by weight/hour and plasticized at 150°C. Next, the aqueous dispersion of the ethylene/acrylic acid copolymer resin shown in the reference example was heated to 80°C through the liquid inlet provided in the first metering zone of the same extruder, and was pressurized with a plunger pump to 10 parts by weight/hour. Continuously supply at a rate of (pressure 1
40 kg/cm2G) Example 1 at an extrusion temperature of 95°C
Similarly, the extruded product is a white fiber bundle with a moisture content of 6%. When the round fiber bundle is pushed out and observed, the fibers appear to be partially bonded and look like unwoven threads, and are not single fibers. The thickness is approximately 70~140μ
[Reference example] Ethylene-acrylic acid copolymer resin (AC polyethylene ■5120A O manufactured by Allied Chemical Co., Ltd. 11 Acrylic acid content 15% by weight, -C-O group = 2.14 mm)
o1 equivalent/g, viscosity (140℃) = 650cps
, density = 0. 93 g/cm3, Sp value=8.
5 8 (Cal/cm3) +72) 3 071
66 parts of water and 3.60 parts of potassium hydroxide (1.0 chemical equivalent per -C-O group) were placed in an autoclave equipped with a stirrer, and heated and stirred at 16140°C for 1 hour (parts are parts by weight). ).

Next, when the autoclave was cooled and the contents were taken out, a white jelly-like emulsion was obtained.9 The particle size of the emulsion was 0.5.
μ or less, and one neutralized O 藷 C-〇 group is 2. 1 mmol equivalent/g
Example 18) Ethylene-propylene copolymer resin (ethylene content 80 mol%,
MFR=1. 1 g 7 1 0 min, density = 0. 8 8 g /cvp, Sp value = 7.
8 7 (Cal/cm3) ''”) and Example 1
A 92/5/3 (weight ratio) mixture of the same maleic anhydride grafted polyethylene and stearic acid used in
It is continuously fed at a rate of 5 parts by weight/hour and plasticized at 120°C. Next, ethylene tetrachloride was added at a rate of 25 parts by weight/hour from the liquid inlet provided in the first compression zone of the same extruder, and 4 parts by weight was added from the liquid inlet provided in the first metering zone of the same extruder.
% potassium hydroxide aqueous solution at a rate of 15 parts by weight/hour using a plunger pump, and extruded at a heating temperature of 80° C. in the same manner as in Example 1, the resulting product was a white fiber bundle. , the single fiber diameter was approximately in the range of 55 to 110 μm. [Example 19] Ethylene-vinyl acetate copolymer resin (vinyl acetate content: 19% by weight,
MFR=150g/10min, density=0.97g/cm', Sp value=8. 0 6
(cal/cm3)'') is continuously supplied at a rate of 98 parts by weight/hour and plasticized at 120°C.Next, polyvinyl alcohol (trade name 10% of Gohsenol ■ KH-1 7 Saponification degree 80%) manufactured by Japan Goei Chemical Industry Co., Ltd.
The aqueous solution was continuously supplied under pressure with a 20 weight pulse plunger pump (pressure: 80 kg/cm2G), and extruded at an extrusion temperature of 90°C in the same manner as in Example 1. The water content was 13%.9 Next, when the fiber bundle was stretched out and observed, the single fibers were lined up in a nearly parallel state, some of which were partially adhered, and the thickness of the single fibers was approximately 35 to 70 μm. However, if the fiber bundle was left at room temperature until the next day, polyvinyl alcohol formed a film and the fibers could not be opened. [Example 20] Ethylene/vinyl acetate used in Example 19 Instead of the copolymer resin, 90 parts by weight of the low-density polyethylene used in Example 1 and hydrogenated petroleum resin (trade name: Alcon p-ioO, manufactured by Arakawa Chemical Co., Ltd., softening point: 100°C, molecular weight: 7)
The fiber thickness of the product was approximately 30 to 60μ, except that the mixture with 00) and 10 parts by weight was continuously supplied at a rate of 98 parts by weight/hour, and the extrusion temperature was 95°C. [Example 21] A raw fiber made in the same manner as in Example 20, except that the hydrogenated petroleum resin in Example 20 was replaced with the maleic anhydride grafted polyethylene used in Example 1. The thickness is generally within the range of 40 to 80μ.
too

[Brief explanation of drawings]

FIGS. 1 to 4 are micrographs showing the fiber shape of the present invention.

Claims (1)

[Claims] (1) Ultrafine fibers in which many thermoplastic resin microfibers with a diameter of 200p or less, which are substantially the same as single fibers molded singly and have a substantially circular cross-sectional shape and substantially indefinite length, are bundled in a substantially parallel state. An ultrafine fiber bundle characterized in that the ultrafine fibers constituting the fiber bundle are partially bonded to each other.