More particularly, the present invention relates to mineral fibers that have smooth surfaces and low specific gravity in addition to showing such multi functions.

Also, the present invention is concerned with a method for preparing such mineral fibers.

BACKGROUND ART There have been developed various fibers that are specialized in their functionality. In this regard, minerals are used to endow fibers with various functions, such as radiation of far infrared rays, antibacterial activity, deodorization, electromagnetic wave shielding, UV shielding, adsorption, hydroscopicity, anion releases, and the like. For use in these purposes, minerals may be natural or synthetic. For example, alunite, amphibole, titanium dioxide (Ti02), silver ions, antibacterial inorganic ions, zeolite, calcium phosphate, zircon, murite, boulder, tourmaline, shell powder, and the like are added to chemical resins from which fibers are prepared. However, such minerals cause various problems in preparing fibers. When fibers are prepared from compositions containing mineral powders through spinning, elongation, false twisting and cutting and when the fibers are weaved to cloths, the mineral powders rub against the machines to wear fittings, such as rollers, guide bodies, etc. Particularly, there is great difficulty in spinning mineral-containing resins.

Minerals can be classified into various groups according to crystal morphologies: columnar, pyramidal, rhombohedral, hexahedral, octahedral, dodecahedral, and tabular groups, or according to hardnesses. Below, there are given examples of minerals belonging to each group.

Classification According to Crystal Structure 1) Columnar : dyscrasite, corundum, rutile, manganite, azurite, malachite, kernite, glauberite, monazite, tantalite, colemanite, brochantite, triphylite, apatite, turquoise, phenakite, willemite, zircon, andalusite, kyanite, topaz, staurolite, datolite, gadolinite, thortveitite, lawsonite, ilvaite, clinozoisite, epidote, zoisite, vesuvianite, beryl, cordierite,

ilvaite, clinozoisite, epidote, zoisite, vesuvianite, beryl, cordierite, tourmaline, dioptase, clinoenstatite, pigeonite, diopside, augite, spodumene, aegirine, aegirineaugite, enstatite, tremolite, common hornblende, glaucophane, riebeckite, arfvedsonite, anthophyllite, nepheline, anorthoclase, orthoclase, microcline, albite, cancrinite, marialite, dipyre, mizzonite, meionite, thomsonite, laumontite, mordenite, mellite, flagstaffite, alunite, hornblende, zircon, mullite, jades, shell particles, tourmaline 2) Rhombohedral: calcite, dolomite 3) Hexahedral: galena, rock salt 4) Octahedral: fluorite, diamond 5) Dodecahedral: sphalerite 6) Tabular: chalcocite, pyrrhotite, marcasite, polybasite, chrysoberyl, ilmenite, brookite, columbite, euxenite, samarskite, gibbsite, brucite, diaspore, boemite, hydromagnesite, polyhalite,, chloritoid, chondrodite, sphene, millerite, hemimorphite, allanite, pumpellyite, hedenbergite, bronzite, hypersthene, wollastonite, rhodonite, pyrophyllite, talc, paragonite, margarite, prehnite, muscovite, phlogopite, biotite, lepidolite, zinnwaldite, beidellite, montmorillonite, nontronite, saponite, vermiculite, penninite, clinochlore, prochlorite, thuringite, kaolinite, antigorite, amesite, cronstedtite, halloysite, sanidine, heulandite, stilbite, phillipsite Monoclinic System Mineral acanthite, polybasite, jamesonite, boulangerite, realgar, orpiment, cryolite, todorokite, manganite, azurite, malachite, hydrozincite, natron, borax, kernite, colemanite, glauberite, brochantite, monazite, lazulite, canotite, chloritoid, chondrodite, sphene, datolite, gadolinite, uranophane, thortveitite, clinozoisite, epidote, allanite, pumpellyite, clinoenstatite, pigeonite, diopside, hedenbergite, augite, spodumene, jadeite, aegirine, aegirineaugite, tremolite, actinolite, common hornblende, glaucophane, riebeckite, arfvedsonite, pyrophyllite, talc, paragonite, muscovite, glauconite, celadonite, margarite, phlogopite, biotite, lepidolite, zinnwaldite, stilpnomelane, beidellite, montmorillonite, nontronite, saponite, vermiculite, penninite, clinochlore, prochlorite, chamosite, thuringite, antigorite, chrysotile, cronstedtite, halloysite, palygorskite, coesite, sanidine, orthoclase, scolecite, laumontite, heulandite, stilbite, phillipsite, harmotome, clinoptilolite, evenkite,

Classification According to Hardness 1) Low hardness (less than 4) dyscrasite, chalcocite, acanthite, enargite, polybasite, cryolite, gibbsite, brucite, boemite, hydrozincite, natron, borax, kernite, alunite, sepiolite, epsomite, uranophane, talc, pyrophyllite, paragonite, muscovite, glauconite, celadonite, margarite, phlogopite, biotite, lepidolite, zinnwaldite, stilpnomelane, beidellite, montmorillonite, nontronite, saponite, vermiculite, penninite, clinochlore, prochlorite (ripidolite), chamosite, thuringite, kaolinite, antigorite, chrysotile, amesite, cronstedtite, halloysite, palygorskite, clinoptilolite, whewellite, mellite, evenkite, and amber 2) High hardness (not less than 4) pyrrhotite, corundum, ilmenite, rutile, brookite, euxenite, samarskite, diaspore, boracite, colemanite, monazite, lazulite, apatite, canotite, phenakite, willemite, forsterite, pyrope, grossular, andradite, zircon, almandine, sillimanite, andalusite, kyanite, mullite, topaz, staurolite, chloritoid, chondrodite, humite, sphene, datolite, gadolinite, thortveitite, millerite, lawsonite, ilvaite, hemimorphite, clinozoisite, epidote, allanite, zoisite, pumpellyite, vesuvianite, benitoite, cordierite, tourmaline, dioptase, clinoenstatite, pigeonite, diopside, hedenbergite, augite, spodumene, jadeite, aegirine, aegirineaugite, enstatite, bronzite, hypersthene, tremolite, common hornblende, glaucophane, riebeckite, anthophyllite, rhodonite, prehnite, tridymite, coesite, nephelin, analcime, leucite, sanidine, anorthoclase, orthoclase, microcline, albite, cancrinite, marialite, dipyre, mizzonite, meionite, scolecite, thomsonite, laumontite, heulandite, stilbite, phillipsite, harmotome, chabasite, mordenite, apophyllite, olivine, lawsonite, janggunite, johachidolite, and suanite In spite of various functionalities, mineral fibers are not widely used because they are very difficult to prepare as mentioned above. Abrasion of machines, caused by the minerals contained in the fibers, lowers the economy of the mineral fibers. In addition, yarn cutting frequently occurs during spinning, so that it is virtually impossible to obtain mineral fibers of sufficient quality.

DISCLOSURE OF THE INVENTION Leading to the present invention, the intensive and thorough research on the preparation of mineral fibers, conducted by the present inventors, resulted in the finding that, when minerals with a crystal structure of column, rhombohedron, hexahedron, octahedron or dodecahedron are compounded with fiber resins, the

yams have rugged surfaces owing to the protrusion of the minerals, but the yams prepared from resinous compositions containing minerals of tabular crystal structures have such smooth surfaces that the abrasion and yarn cutting problems can be reduced.

Therefore, it is an object of the present invention to overcome the above problems encountered in prior arts and to provide a mineral fiber that is easy to spin and does not damage fiber machines, as well as being multifunctional.

It is another object of the present invention to provide a method for preparing such a mineral fiber.

In accordance with an aspect of the present invention, there is provided a method for preparing a functional fiber, comprising the steps of : baking a mineral with a multi-sided crystal structure and a low-hardness mineral with a tabular or scale crystal structure, the multi-sided crystal structure being selected from the group consisting of pyramid, column, rhombohedron, hexahedron, octahedron, and dodecahedron, the low hardness mineral being selected from the group consisting of phyllosilicates, muscovites, biotites, montmorlillonites, chlorites, kaolinite- serpentines; milling the minerals to a particle diameter as small as or smaller than 1/3 of the fineness of the fiber, separately ; admixing 40 to 90 weight parts of the mineral with the multi-sided crystal structure, 10 to 60 weight parts of the mineral with the tabular or scale crystal structure, and 10 to 30 weight parts of an inorganic antibiotic to give an additive mixture; compounding 1 to 10 % by weight of the additive mixture with 90 to 99 % by weight of a resin to produce a chip, said resin being selected from the group consisting of polyester, nylon, polyamide, polypropylene, polyacrilonitrile, viscose rayon, and acetate rayon; and spinning the chip to a filament or a staple.

In accordance with another aspect of the present invention, there is provided a mineral fiber prepared by the method.

BEST MODES FOR CARRYING OUT THE INVENTION The mineral fiber of the present invention is characterized in that at least one mineral which is of tabular or scale in crystal structure and has a low hardness is used in a certain proportion, in combination with at least one mineral which is multi-sided in crystal structure, such as hexahedrons, octahedrons, dodecahedrons, and the like, and has a high hardness.

For use in mineral fibers, minerals are baked and milled to a diameter as small as or smaller than 1/3 of the fineness of a fiber desired. Minerals useful in the present invention are grouped into two categories: minerals whose crystal structures are of tabular or scales; and minerals whose crystal structures are in

multi-sided forms, such as pyramidal, columnar, rhombohedral, hexahedral, octahedral, or dodecahedral forms.

Examples of the minerals which are of tabular or scales in crystal structure and low in hardness include: Phyllosilicates pyrophyllite-Al2Si4O10 (OH) 2 Muscovite Group (dioctahedral) 1. paragonite-NaAl2 (Al, Si3) 010 (OH) 2 2. muscovite-KAl2 (AlSi3) Olo (OH) 2 3. (K, Na) (Al, Fe3Mg) 2 (Al, Si) 40to (OH) 2 4. celadonite-K (Mg, Fe) (Fe3, Al) Si401o (OH) 2 5. margarite-CaAl2 (Al2Si2) O I o (OH) 2 6. micaschist 7. lepidomelane-KFeAlSiO (OH, F) Biotite Group 1. phlogopite-KMg3 (AlSi3)O10 (F, OH) 2. lepidolite-K (Li, Al) 3 (Si, Al) 4010 (F, OH) 2 3. zinnwaldite-KliFeAl (Al, Si3) 010 (F, OH) 2 4. stilpnomelane-K (Fe, Fe, Al) lOSi22030 (OH) 12 Montmorilonite Group 1. beidellite-(Na,Ca/2)0.03Al2(Al, Si) 40io (OH) 2#nH2O 2. montmorillonite-(Na, Ca) o. 03 (Al, Mg) 2Si4O10 (OH) 2#nH2O 3. nontronite-Na0. 33Fe2 (Al, Si) 4O10 (OH) 2#nH2O 4. saponite- (Ca/2, Na) o. 33 (Mg, Fe) 3 (Si, Al) 40lo (OH) 2-4H20 5. vermiculite-(Mg, Fe, Al) 3 (Al, Si) 4010 (OH) 2-4H20 Chlorite Group 1. penninite 2. clinochlore- (Mg, Fe2) sAl (Si, Al) 401o (OH) 8 3. prochlorite (ripidolite)- (Mg, Fe, Al) 6 (Si, Al) 40) o (OH) s 4. chamosite- (Fe2, Mg, Fe3) sAl (Si3Al) O10(OH,O)8 5. thuringite Kaolinite-Serpentine Group 1 kaolinite-Al2SiO5 (OH) 4 2. antigorite- (Mg, Fe) 3Si2O5 (OH) 4 3. chrysotile-Mg3Si205 (OH) 4 4. amesite-(Mg2Al)(AlSi)O5 (OH) 4 5. cronstedtite 6. halloysite-Al2Si2O5 (OH) 4-2H20 : dehydrated into A12Si205 (OH) 4 7. palygorskite (attapulgite)- (Mg, AI) 2Si40lo (OH) 4H20

After being baked and milled, 40-90 weight parts of the mineral with tabular or scale crystal structure is admixed with 10-60 weight parts of the mineral with multi-sided crystal structures, along with 10-30 weight parts of an inorganic antibiotic. Silver, calcium phosphate and/or zeolite may be used as an antibiotic.

Then, this resulting additive mixture is compounded with a resin. The resin useful in the present invention is selected from the group consisting of polyester, nylon, polyamide, polypropylene, polyacrylonitrile, viscose rayon, and acetate rayon. The compounding is achieved with 1-10 % by weight of the additive mixture and 90-99 % by weight of the resin. The compounded material is spun to filaments or staples by a conventional method, such as conjugated spinning.

According to the fineness of the yarn spun, the relative proportion of the mineral additive to the resin varies. When the yarn is spun to a fineness of 3 deniers or less, the mineral additive is preferably added in an amount of 1 to 3 % by weight. In the case of the yarn thicker than 3 deniers, the mineral additive is preferably used in amount of 3 to 10 % by weight.

Next, the yarn is subjected to ordinary processing necessary for preparing final fibers, such as elongation, false twisting, cutting, and weaving.

A better understanding of the present invention may be obtained in light of the following examples which are set forth to illustrate, but are not to be construed to limit the present invention.

EXAMPLE 1 Jade (nephrite, beryl, jadeite, jacinth, ruby) with tabular crystal structures, and mica with non-tabular crystal structures were separately pulverized to a particle size of 325 meshes, after which baking was conducted at 800 to 1,200 °C to remove impurities. Again, the particles were milled to a diameter of up to 1 micron. 40 weight parts of the jade powder was admixed with 60 weight parts of the mica powder, along with 10 weight parts of an inorganic antibiotic (silver, zeolite, or calcium phosphate) powder. The resulting additive powder was compounded at a weight ratio of 2: 98 with a polyester. After being melted, the compounded resin was spun at 2831 °C to filaments with a fineness of 2 deniers, by an ordinary method. Subsequently, the filaments were elongated and false- twisted. The multi-functional filaments were observed to have smooth surfaces and low specific gravity, as well as showing high far infrared radiation. The spinning was conducted at a high efficiency without abrasion of machines nor yarn cutting.

EXAMPLE 2

Filaments were prepared in the same manner as in Example 1, except that polyamide was used instead of polyester.

EXAMPLE 3 A resin chip with a melt index of about 2,700 poise comprising an additive powder and a polyester was prepared in the same manner as in Example 1, except that the compounding was conducted at 290 °C. The chip was then spun at 2831 °C to staples with a fineness of 1.4 deniers, by an ordinary method.

Subsequently, the staples were subjected to ordinary processing, including elongation, false-twisting, cutting and texturing. The multi-functional staples were observed to have smooth surfaces and low specific gravity. The spinning was conducted at a high efficiency without abrasion of machines nor yarn cutting.

EXAMPLE 4 Alunite particles, which are tabular in crystal structure, and vermiculite particles, which are non-tabular in crystal structure, were separately pulverized to a diameter of 1 micron or less, after which 22 weight parts of the alunite particles was admixed with 78 weight parts of the vermiculite particles, along with 20 weight parts of an inorganic antibiotic. The resulting additive powder was compounded at a weight ratio of 2: 98 with a polyacrilonitrile. After being melted, the compounded resin was spun to staples with a fineness of 1.4 deniers, by a conjugated spinning method in a wet condition. Subsequently, the staples were subjected to ordinary processing, including elongation, false-twisting, cutting and texturing. The multi-functional filaments were observed to have smooth surfaces and low specific gravity, as well as showing high functionality in terms of antibacterial activity, deodorization, far infrared radiation, and hygroscopicity.

The spinning was conducted at a high efficiency without abrasion of machines nor yarn cutting.

EXAMPLE 5 Staples were prepared in the same manner as in Example 4, except that viscose rayon polyamide was used instead of polyester.

EXAMPLE 6 After being baked, tourmaline with a non-tabular crystal structure and muscovite with a tabular crystal structure were separately milled to a diameter of 5

microns. 35 weight parts of the tourmaline powder was admixed with 65 weight parts of muscovite, along with 30 weight parts of a inorganic antibiotic. The resulting additive powder was melted at a weight ratio of 20: 80 with a polyester to give a master batch chip. 20 % by weight of the master batch chip was compounded with 75 % by weight of a polyester and spun to staples with a fineness of 6 deniers, by an ordinary method. Subsequently, the staples were subjected to ordinary processing, including elongation, false-twisting, and cutting.

The staples were observed to have smooth surfaces and low specific gravity, as well as showing high functionality in terms of far infrared radiation and anion release. The spinning was conducted at a high efficiency without abrasion of machines nor yarn cutting.

EXAMPLE 7 A mineral mixture containing a mineral with a tabular crystal structure and at least one mineral selected from groups consisting of columnar, rhombohedral, octahedral, dodecahedral, pyramidal, and monoclinic system minerals was compounded with at least one resin selected from the group consisting of polyester, polyamide, nylon, polypropylene, polyacrylonitrile, viscose rayon, and acetate rayon in the same manner as in one of Examples 1 to 6.

From the resulting compounded resin, yams with smooth surfaces were prepared.

As described hereinbefore, the use of a mineral with a tabular crystal structure affords yarns which have smooth surfaces and low specific gravity in addition to showing multi functionality, including far infrared ray emission, antibacterial activity, deodorization, electromagnetic wave shielding, UV shielding, anion release, adsorptivity, hygroscopicity, pleasantness, and thermo- keeping ability. The mineral yams of the present invention are spun, elongated, false-twisted and textured without machine abrasion nor yarn cutting.

The present invention has been described in an illustrative manner, and it is to be understood that the terminology used is intended to be in the nature of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.