KR100557271B1 - Divisible hollow copolyester fibers, and divided copolyester fibers, woven or knitted fabric, artificial leather and nonwoven fabric comprising same - Google Patents

Abstract

Detachable hollow copolyester fibers having satisfactory processing properties, such as carding properties, which can be separated into fibrid fine fibers by applying mechanical forces, each comprising a hollow enclosed by a shell, the longitudinal axis of the hollow fiber Wherein the shell is made from a copolyester of an acid component comprising 1 to 6 mol% of terephthalic acid and a sulfonate group containing dicarboxylic acid and a diol component comprising ethylene glycol; The hollow fiber is (1) the thickness of 0.56 to 8.89 d tex, (2) the hollow ratio 25/100 to 85/100, (3) the crystallinity of 20 to 30% and (4) in the (010) plane of 4.0 to 8.7 nm Has a crystal size; Each shell has a number of cracks that intermittently extend along the longitudinal axis of the hollow fiber.

Description

Detachable hollow copolyester fibers and separated copolyester fibers, woven or knitted fabrics comprising the same, artificial leather and nonwovens

1 shows an electron microscope side view of a cross section of a detachable hollow copolyester fiber embodiment of the present invention.

2 shows an electron microscope view of a separable hollow copolyester fiber embodiment of the present invention.

3 shows an electron microscope view of an isolated copolyester fiber embodiment of the present invention.

The present invention relates to separable hollow copolyester fibers that can be easily separated into fine copolyester fibers by applying mechanical force to the hollow fibers; Isolated copolyester fibers produced therefrom; And woven or knitted fabrics, artificial leather and nonwovens, each comprising isolated copolyester fibers.

More specifically, the present invention relates to separable hollow copolyester fibers which can be separated into fine copolyester fibers by applying mechanical force to the hollow fibers; And isolated fine copolyester fibers made from hollow copolyester fibers; And fine copolyester fibers, including woven or knitted fabrics with high thermal insulation properties and good feel, fine copolyester fibers, and artificial leather and nonwoven fabrics having a soft touch.

There has been a strong demand for microfine fibers in the industry, and various attempts have been made to use and manufacture microfine fibers.

For example, microfibers may be melt-extruded into a spinning machine having a small diameter spinning hole, wound extruded filamentous polymer melt streams at high speed to produce unstretched filaments, and stretched unstretched filaments at high draw ratios. Methods of making are known. This method is limited to the resulting individual fiber thicknesses of about 0.33 d tex or more, thus making it difficult to manufacture microfibers having a thickness of less than 0.33 d tex, and even if it is possible to produce them themselves, the productivity of microfibers is very high. It is low and its manufacturing cost is very high.

According to the method disclosed in Japanese Patent Laid-Open No. 42-19518, it is extremely fine by spinning, dissolving a mixture of two polymers that are insoluble in each other, and removing one of the two polymers from the resulting mixed polymer fiber using a solvent. Fibers can be produced. However, this method allows the obtained fragments formed from two insoluble polymers to be easily separated at the interface therebetween, so that the obtained composite fibers are difficult to pass through the carding machine, the resulting fiber thickness is very thin, and the length of the resulting fiber is The disadvantage of being too short and too random is that the resulting fibers cannot be used for a particular purpose.

In addition, Japanese Patent Application Laid-Open Nos. 47-30,723 and 4-153,321 disclose that two polymers which are insoluble in each other are arranged in an islands-in-sea form or in a radial form or an alternating lamination form. A method for producing ultrafine fibers is disclosed by preparing a composite fiber and dissolving-removing one polymer from the composite fiber. This method is useful for the production of ultrafine fibers or filaments having the desired thickness and fiber length. However, this method has the disadvantage that the productivity of the ultrafine fibers is low and the production cost of the ultrafine fibers is high due to the complicated procedure of dissolving and removing one of the two polymers from the composite fiber.

Further, Japanese Patent Laid-Open No. 62-133,164 forms a composite fiber in which two or more polymers are arranged in a radial form or alternating lamination form, and utilizes the thermal expansion difference between two polymers, the shrinkage difference of two polymers, or It discloses a method for producing ultrafine fibers by applying a mechanical force to the composite fibers to separate the composite fibers. However, this method has a disadvantage in that the separation properties of the composite fibers are insufficient, so that a large number of polymers are used, and the production apparatus is complicated and the productivity of the ultrafine fibers is low.

In addition, Japanese Patent Laid-Open Nos. 8-325,945 and 8-260,343 form hollow fibers from polymers mixed with specific additives, add a treating agent such as an alkali treating agent for weight reduction of the hollow fiber, and Disclosed are methods for producing ultrafine fibers by separating polymer segments which are connected to one another, surrounding hollow spaces. This method has the disadvantage of limiting the spinning nozzle design for forming hollow fibers from a plurality of polymer fragments, and the limitation of the number of separated fibers or the thickness of the separated fibers. In addition, there is a limit to the use of the resulting separation fibers because an alkali treatment agent is required.

As mentioned above, the known production method of the ultrafine fibers by the conventional composite fiber separation method or the conventional single component polymer-removal method does not satisfactorily produce the ultrafine fibers useful in various fields with high efficiency.

An object of the present invention is a separable hollow fiber which has satisfactory processing properties, for example in carding processes for the manufacture of textile products, and which can be easily separated into a plurality of fine fibers by applying mechanical force to the hollow copolyester fibers. Copolyester fibers, separated fine copolyester fibers made from the hollow copolyester fibers, woven or knitted fabrics containing the separated fine copolyester fibers and having high thermal insulation properties and good hand feel, the separated fine fibers It is to provide a non-woven fabric containing copolyester fibers, comprising artificial leather having a soft touch, and the separated fine copolyester fibers, which is useful for paper sheet materials and packaging materials and has a soft touch.

This object can be achieved by the separable hollow copolyester fibers, the separated fine copolyester fibers, woven and knitted fabrics, artificial leather and nonwovens of the present invention.                         

The separable hollow copolyester fibers of the present invention extend along the longitudinal axis of (A) the hollow copolyester fibers in one or a plurality of hollow portions and (B) the hollow copolyester fibers. A dicarboxylic acid component surrounding the hollow portion and containing terephthalic acid and one or more of the sulfonate group-containing dicarboxylic acids in an amount of 1 to 6 mol% based on the total molar amount of the dicarboxylic acid component, and ethylene glycol It consists of a shell comprising a copolyester of the diol component comprising a, wherein the hollow copolyester fibers (1) the thickness of 0.56 to 8.89 d tex, (2) the total cross-sectional area / ratio of the total cross-sectional area of the individual fibers of the hollow portion 25/100 to 85/100, (3) the degree of crystallinity of copolyester 20 to 30% and (4) the crystal size in the (010) plane of copolyester of 4.0 to 8.7 nm,

The shell of the hollow copolyester fiber has a large number of cracks intermittently extending along the longitudinal axis of the hollow copolyester fiber at any position of the shell, whereby when applying a mechanical force to the shell of the hollow copolyester fiber It can be separated into a plurality of fine fibers.

The separated fine copolyester fibers of the present invention are made from the separable hollow copolyester fibers by applying mechanical force to the shell of the separable hollow copolyester fibers.

The woven or knitted fabric of the present invention comprises the separated fine copolyester fibers, preferably in an amount of 20 to 100% by weight, based on the total weight of all fibers contained in the woven or knitted fabric.

The artificial leather of the present invention comprises a base sheet containing the separated fine copolyester fibers in an amount of preferably 20 to 100% by weight and a synthetic resin impregnated with the base sheet.

The nonwovens of the present invention comprise a plurality of fibers interlaced with or bonded to each other by a binder, wherein the separated fine copolyester fibers are preferably 30 to 100 based on the total weight of the fibers contained in the nonwoven fabric. In amounts by weight.

The separable hollow copolyester fibers of the present invention comprise (A) one or a plurality of hollow portions extending along the longitudinal axis of the hollow copolyester fibers and (B) a hollow copolyester fiber extending along the longitudinal axis and surrounding the hollow portion. It includes a shell.

The shell portion of the separable hollow copolyester fibers of the present invention comprises terephthalic acid and one or more sulphonate group containing dicarboxylic acids in an amount of 1 to 6 mole percent, based on the total moles of the dicarboxylic acid component. An acid component and a copolyester of diols containing ethylene glycol. That is, the copolyester includes ethylene terephthalate units and at least one ethylene sulfonic acid group-containing dicarboxylic acid ester unit as main repeating units.

In addition, the hollow copolyester fibers of the present invention are (1) the thickness of 0.56 to 8.89 d tex, (2) the total cross-sectional area of the hollow portion / the total cross-sectional area ratio of the individual fibers 25/100 to 85/100, (3) copolyester Crystallinity of 20 to 30% and (4) copolyester crystal size in the (010) plane of 4.0 to 8.7 nm.

In addition, the shell of the hollow copolyester fiber of the present invention extends intermittently substantially along the longitudinal axis of the hollow copolyester fiber and has a plurality of cracks arbitrarily located in the shell, whereby the shell of the hollow copolyester fiber Mechanical forces can be applied to the part to separate it into a number of fine fibers.

Referring to FIG. 1, where the cross section of the separable hollow copolyester fiber of the present invention is shown by electron microscopy, a number of cracks are found in the cross section. The cracks penetrate from the outer surface of the shell to the inner surface of the hollow part.

Referring to FIG. 2, which shows an electron microscope measure of the separable hollow copolyester fibers of the present invention, a number of intermittent cracks or slits are found in the shell of the hollow fiber. The crack or slit has a certain length and extends substantially along the longitudinal axis of the hollow fiber.

In the case of applying a mechanical force, such as a blow, the shell of the hollow copolyester fiber of the present invention is separated into a plurality of fine copolyester fibers along the longitudinal axis of the hollow fiber, as shown in FIG. 3.

The separated fine copolyester fibers can be broken by mechanical forces.

In the copolyester fibers of the separable hollow copolyester fiber shells of the present invention, the dicarboxylic acid component is 1 to 6 mol%, preferably 2 to 5, of one or plural sulfonate group-containing dicarboxylic acids in addition to terephthalic acid. It contains mole%. If the sulfonate group-containing dicarboxylic acid content in the dicarboxylic acid component is less than 1 mol%, the resulting hollow copolyester fiber shell may be unsatisfactory in terms of crack formation intermittently extending along the longitudinal axis of the hollow copolyester fiber. have. Thus, it can be difficult to separate the shell into a large number of fine fibers, especially microfibers. In addition, if the sulfonate group-containing dicarboxylic acid content in the dicarboxylic acid component is more than 6 mol%, the stability of melt-spinning processing for the production of separable hollow copolyester fibers is very low. On the other hand, cracks extending along the longitudinal axis of the hollow copolyester fiber may be formed in the shell portion.

Sulfonate group-containing dicarboxylic acids useful in the present invention include sulfonate group-containing aromatic and aliphatic dicarboxylic acids, preferably 5-sodium sulfoisophthalic acid, 5-potassium sulfoisophthalic acid, 5-lithium sulfide Poisophthalic acid, 4-sodium sulfoisophthalic acid, 4-sodium sulfo-2,6-naphthalene dicarboxylic acid and ester forming derivatives of these acids can be selected. The sulfonate group-containing dicarboxylic acid may be used alone or in combination of two or more.

In copolyesters useful in the present invention, the dicarboxylic acid component may contain one or more additional dicarboxylic acids in addition to the terephthalic acid and sulfonate group containing dicarboxylic acids, the diol component being used to achieve the object of the present invention. As long as it does not interfere, it may contain one or more additional diols in addition to ethylene glycol.

Additional dicarboxylic acids are preferably aromatic dicarboxylic acids such as isophthalic acid, diphenyldicarboxylic acid and naphthalene dicarboxylic acid; Aliphatic dicarboxylic acids such as succinic acid, adipic acid and sebacic acid; And oxycarboxylic acids such as parahydroxybenzoic acid and 4- (β-hydroxyethoxy) benzoic acid. The additional dicarboxylic acid may be used alone or in combination of two or more.

Additional diols are preferably aliphatic diols such as 1,3-propane diol, 1,6-hexane diol and neopentylglycol; Aromatic diols such as 1,4-bis (β-hydroxyethoxy) benzene; And polyalkylene glycols such as polyethylene glycol and polypropylene glycol.

The additional diols may be used alone or in combination of two or more.

Preferably the additional dicarboxylic acid and additional diol are used in an amount of up to 10 mol%, based on the total molar amount of the dicarboxylic acid component.

In general, with respect to the polyester resin for fibers, the greater the degree of polymerization of the polyester, the lower the stability of melt spinning processing of the polyester, and the more difficult it is to produce fine fibers. In addition, the lower the degree of polymerization of polyester, the more difficult it is to produce hollow fibers with large hollow spaces. Thus, the copolyesters useful in the present invention preferably have an intrinsic viscosity (η) of 0.35 to 0.70, more preferably 0.40 to 0.55, measured in orthochlorophenol at a temperature of 35 ° C.

Copolyesters for the shell of the separable hollow copolyester fibers of the present invention are optionally added with one or more additives.

Additives include functionalizing agents such as antibacterial agents, hydrophilicizing agents, anti-mite agents and deodorants; And inorganic particles such as titanium dioxide, zinc oxide, barium sulfate, zirconium oxide, aluminum oxide, magnesium oxide, calcium oxide and tourmaline. The additive may be selected in consideration of the purpose of use of the end product of the separable hollow copolyester fibers. When inorganic particles are used, the inorganic particles are preferably 1.0 µm or less in particle size, more preferably 0.1 to 0.7 µm, and 1 to 10% by weight, more preferably 2 to 7, in the shell portion of the hollow copolyester fiber. It is contained in an amount of% by weight.

The separable hollow polyester fibers of the present invention have an individual fiber thickness of 0.56 to 8.89 d text, preferably 1.11 to 4.44 d text, more preferably 1.67 to 3.33 d text. If the individual fiber thickness is less than 0.56 d tex, the separable hollow copolyester fibers cannot be produced with satisfactory melt spinning processing stability, and the resulting hollow copolyester fibers have an unsatisfactory hollow ratio (cross-sectional area / hollow fiber of the total hollow part). Of cross-sectional area). In addition, if the individual fiber thickness is more than 8.89 d tex, the melt spinning processing stability is excellent, while the shell portion of the resulting hollow copolyester is too thick, so that cracks are not satisfactorily formed along the longitudinal axis of the hollow copolyester. And even if a mechanical force is applied to the shell, it does not separate into satisfactory fine fibers.

The separable hollow copolyester fibers of the present invention have a hollow ratio (total cross-sectional area of the hollow portion / total cross-sectional area of the individual hollow fibers) of 25/100 or more, preferably 40/100 to 60/100. If the hollow ratio is less than 25/100, even if a mechanical force is applied to the hollow copolyester fibers obtained, they cannot be separated into satisfactorily thin fibers. However, if the hollow ratio is too high, the thickness of the hollow fiber shell produced is thin, easily broken during processing and melt spinning processing, and exhibits poor mechanical properties. Usually, the hollow ratio of the hollow copolyester fibers is preferably 85/100 or less.

In each of the separable hollow copolyester fibers of the present invention, a single hollow portion is preferably formed such that the cross section of the hollow portion is substantially concentric with the cross section of the hollow fiber, so that the shell portion has a substantially uniform thickness. Have If the cross section of the hollow part is eccentric with the cross section of the hollow fiber, the shell part is uneven. The greater the eccentricity, the greater the uniformity of the shell thickness. Thus, the resulting shells are difficult to uniformly separate into fine fibers, and thus the resulting separated fine fibers are difficult to form a base sheet for woven, knitted or nonwoven or artificial leather having a soft touch.

In the separable hollow copolyester fibers of the present invention, the shell surrounding the hollow portion preferably has an average thickness of 5 μm or less, more preferably 1.0 to 3.0 μm. The shell having an average thickness of 5 μm can be satisfactorily separated into thin fibers. However, if the thickness of the shell is too thin, the production of hollow fibers may be difficult, and the hollow fibers may easily break during fracture and / or exhibit poor wear resistance.

The separable hollow copolyester fibers of the present invention have a copolyester (010) of at least 4.0 nm, preferably 5.0 to 8.7 nm, measured from half of the (010) planar diffraction peak width value shown in wide-angle X-ray diffraction photography. ) Crystallite size and copolyester crystallinity of at least 20%, preferably from 22 to 33%. If the copolyester has a crystallinity of at least 20% and a crystal size in the (010) plane of at least 4.0 nm, the resulting hollow copolyester fibers exhibit satisfactory separation properties. If the degree of crystallinity is less than 20% and / or the crystal size is less than 4.0 nm, the resulting hollow copolyester fibers exhibit unsatisfactory separation properties and are therefore difficult to separate into a large number of fine fibers, especially ultrafine fibers.

In the separable hollow copolyester fibers of the present invention, the shell portion is optionally located in the shell portion and has a plurality of cracks that extend intermittently along the longitudinal axis of the hollow copolyester fiber. The cracks have a limited length in the longitudinal axis direction of each hollow copolyester fiber and can penetrate completely or incompletely through the shell. The cracks may be in the form of slits or long narrow openings. Cracks may include potential cracks that can easily be cut when the mechanical force is applied to the shell. If no cracks are formed, the shell cannot be easily separated into fine fibers by applying mechanical force to the shell.

When the separable hollow copolyester fibers of the present invention described above have excellent mechanical properties in the longitudinal direction thereof, the mechanical properties of the hollow fibers in the transverse direction are poor. Thus, preferably, when mechanical force is applied to the shell of the hollow fiber, 90-100% of the hollow fiber is at least 4 fine fibers each, mainly along the intermittently elongated crack in the substantially longitudinal axis of the hollow fiber, More preferably, it is separated into 5 to 20 fine fibers.

Thus, ultrafine fibers can be made from the separable hollow copolyester fibers of the present invention. In addition, when heat-removable hollow copolyester fibers under tension before applying mechanical force, the separation properties of the hollow fibers can be reinforced.

The separable hollow copolyester fibers of the present invention may be in the form of continuous filament or staple fibers, which may be selected according to the use and purpose of the hollow fibers.

The separable hollow copolyester fibers of the present invention can be produced, for example, by the following specific melt spinning processing.

The melt of copolyester is extruded into a hollow filament spinner having a plurality of spinner holes for forming hollow filaments, and heated gas at a temperature of 150 to 230 ° C., preferably 180 to 210 ° C., located below 0 to 50 mm Blowed toward the extruded hollow filamentous copolyester melt stream in the heating zone. The blowing angle of the heating gas is an angle of 30 to 45 degrees downward from the right direction with respect to the transverse hardness of the extruded hollow filamentous copolyester melt stream. That is, the blowing of the heating gas is upward while the movement of the extruded hollow filamentous copolyester melt stream is downward. Thus, blowing of the heating gas and traversing the hollow filamentous copolyester melt stream are carried out in opposite directions to each other.

The blowing speed of the heating gas is 1.0 to 5.0 m / sec, preferably 2.0 to 3.0 m / sec.

After passing through the heating zone, the hollow filamentous copolyester melt stream is located below the heating zone, passes through a buffer zone having a length of 50 to 150 mm, and then below the buffer zone, 100 It is cooled and solidified in a cooling zone having a length of from to 450 mm, preferably from 150 to 350 mm. In the cooling zone, cooling air at a temperature of 15 to 35 ° C., preferably 20 to 25 ° C., is directed towards the hollow filamentous copolyester melt stream at a blowing rate of 0.2 to 4.0 m / sec, preferably 1.5 to 3.5 m / sec. Blows. If the cooling process is carried out under conditions other than those described above, the resulting hollow filaments may be unsatisfactory in terms of certain properties.

The cooling-solidified copolyester filaments are at least 150, preferably 150 to 500, more preferably 200 at a take-up rate of 500 to 2000 m / min, preferably 1000 to 1800 m / min. Can be wound under a draft of from 400 to 400;

If the spin draft is less than 150, melt spinning processing stability is unsatisfactory, and the crystal size in the copolyester (010) plane in the microstructure of the resulting fiber may be too small. Also, if the winding speed is greater than 2000 m / min, the crystal size of the copolyester in the microstructure of the hollow copolyester produced in the (010) plane can be sufficiently large, while all hollows having a hollow ratio of 25/100 or more Copolyester fibers and satisfactory crystallinity and crystal size cannot be obtained.

In addition, if the winding speed is less than 500 m / min, the resulting hollow fibers may have unsatisfactory crystal size in the (010) plane. If the melt spinning draft is too high, the resulting unstretched hollow copolyester filaments may exhibit low stretch. Thus, the melt-drawn draft preferably does not exceed 500.

The resulting undrawn hollow filaments are drawn and optionally heat treated to the limits established according to the end use of the resulting hollow copolyester fibers. The stretching is performed at a stretching ratio of 2.0 to 5.0, for example, in hot water at a temperature of 50 to 70 ° C. If no heat treatment is applied, the resulting stretched hollow copolyester fibers exhibit high thermal shrinkage. When heat treatment is applied under tension using a heating roller or heating plate, the resulting hollow copolyester fibers exhibit reduced shrinkage. In addition, when the non-stretched hollow copolyester filaments are stretched and subsequently heat treated in hot water while overfeeding the filaments in the heat treatment process, the resulting hollow copolyester fibers exhibit self-expansion properties. During the stretching process, this particular microstructure of the hollow fiber is located randomly in the shell and causes a large number of cracks that intermittently extend along the substantially longitudinal axis of the hollow fiber to be formed in the shell.

Intermittent cracks can penetrate completely or incompletely from the outer surface of the hollow fiber through the shell to the inner surface of the hollow part.

The stretched hollow copolyester fibers of the present invention are not visible in the shell of the hollow fibers, and have the potential cracks that cause the shell of the hollow copolyester fibers to separate into thin fibers.

The melt spinning process is merely representative and does not limit the process for producing the separable hollow copolyester fibers of the present invention. That is, the separable hollow copolyester fibers of the present invention can be produced by another method.

The separable hollow copolyester fibers of the present invention can be used alone or in other fibers, such as synthetic polymer fibers and natural fibers other than the hollow copolyester fibers of the present invention such as cotton and wool fibers, semisynthetic fibers such as viscose rayon fibers. Used in combination with When separable hollow copolyester fibers are contained and separated into fine fibers, the resulting fibrous product exhibits reinforced soft hand and bulkiness.

The woven or knitted fabric of the present invention comprises the separated fine copolyester fibers of the present invention. In the woven or knitted fabric, the separated fine copolyester fibers are preferably contained in an amount of at least 20% by weight, more preferably at least 30% by weight, based on the total weight of the fibers contained in the woven or knitted fabric. When the woven fabric or knitted fabric is formed from fibrous yarns containing separable hollow copolyester fibers in an amount of at least 20% by weight, the hollow copolyester fibers in the woven fabric or knit fabric are made into fine fibers during the weaving or knitting of the woven fabric or knit fabric. Are separated.

The resulting separated fine fibers contribute to reinforcing the thermal insulation properties, bulkiness and / or soft hand of the woven or knitted fabric.

The artificial leather of the present invention comprises a base sheet containing the separated fine copolyester fibers of the present invention and a synthetic resin impregnated with the base sheet. The base sheet is in the form of a woven or knitted or nonwoven fabric. The separated fine copolyester fibers are preferably present in the substrate sheet in an amount of at least 20% by weight, more preferably at least 30% by weight.

When the base sheet containing the separable hollow copolyester fibers of the present invention is processed for artificial leather production, the hollow copolyester fibers are separated into fine copolyester fibers during the artificial leather production process. Thus, the resultant artificial leather of the present invention exhibits reinforced soft touch, light weight and flexibility.

The nonwovens of the present invention comprise a plurality of fibers interwoven with one another or bonded through a binder and comprising the separated fine copolyester fibers of the present invention. The content of the fine copolyester fibers separated from the nonwoven is preferably at least 30% by weight, more preferably at least 40% by weight, even more preferably at least 50% by weight.

When the nonwoven fabric is formed by mixing fibers containing separable hollow copolyester fibers with each other, during the mixing process, the separable hollow copolyester fibers are separated into fine copolyester fibers. The resulting nonwovens exhibit enhanced soft hand, light weight and thermal insulation properties.

When the nonwoven fabric is produced by a paper machine, the separable hollow copolyester fibers are cut into fiber lengths of 3 to 30 mm, and the resulting cut hollow fibers are subjected to mechanical pulp processing using a blower such as a disc refiner. The fibrid fibers are separated into fine fibers. Pulp (hit) processing for hollow fibers is carried out under conditions formed according to the type of blower. The resulting isolated fibrid-formed fine fibers obtained from the separable hollow copolyester fibers are suspended in water. The sheet forming binder is added to the resulting thin fiber slurry, and then fed to a paper machine such as a long wire paper machine, a short wire paper machine or a cylinder paper machine, and the resulting wet-deposited nonwoven fabric is hot air dried using a Yankee dryer. The wet-deposited nonwoven fabric produced by the wet method exhibits a uniform and soft hand that was not obtained by conventional nonwoven fabrics. If the separated fine copolyester fiber slurry is unsatisfactory due to insufficient dispersion or bubbles of the fibers, conventional additives such as dispersants or thickeners may be added to the fiber slurry.

Useful binders for the wet-deposited nonwovens of the present invention include conventional paper-forming adhesives such as natural water soluble polymers such as gelatin and sodium alginate; Semi-synthetic water soluble polymers such as phosphoric acid modified starch, cyanoethylated starch, carboxymethyl cellulose and hydroxypropylmethylcellulose; Synthetic water soluble polymers such as polyvinyl alcohol, poly (sodium acrylate) and polyacrylamide; And other water soluble high molecular materials such as polyethylene glycol and polyphosphate. The binder materials may be used alone or in combination of two or more. The binder for the wet-deposited nonwoven can be selected from latexes of water soluble polymers such as vinyl chloride, vinyl acetate, styrene, acrylonitrile acrylate esters, butadiene and ethylene homopolymers and copolymers. The latex may contain plasticizers and / or stabilizers.

The binder for the wet-deposited nonwoven may be in the form of fibers. The binding fibers may preferably be selected from polyvinyl alcohol fibers and polyethylene oxide fibers exhibiting binding activity under moist heat conditions after the paper forming process. Alternatively, the bonding fibers may be heat-melt fibers of heat-melt adhesive homopolymers and copolymers, such as polypropylene fibers, chlorosulf, that exhibit adhesive properties at temperatures between 80 and 170 ° C. at which wet-deposited nonwovens made by paper machines are dried. Side-by side type and sheath centers, including fonned polyethylene fibers and ethylene vinyl-acetate copolymer fibers and other polymers having a melting point of 20 ° C. higher than the heat-melting adhesive polymer and the heat-melting adhesive polymer It is selected from this core-in-sheath type heat-adhesive composite fiber.

In the nonwoven fabric of the invention produced by the wet process, the separated fibrid fine copolyester fibers of the invention are preferably contained in an amount of at least 30% by weight based on the total weight of the wet-deposited nonwoven fabric. In addition, the paper-forming binder is preferably contained in an amount of 5 to 30% by weight, based on the total weight of the wet-deposited nonwoven fabric. If the amount of binder is less than 5% by weight, the resulting wet-deposited nonwoven can exhibit unsatisfactory mechanical strength and can be difficult to handle. In addition, if the amount of binder is greater than 30% by weight, the individual fibrid fibers are bonded to each other at a rate where the fibers cross each other in too wide a range, so that the resulting wet-deposited nonwoven fabric is expected from the use of fibrid fibers. It cannot exhibit a soft touch. The wet-deposited nonwovens of the present invention optionally contain additional fibers, such as natural pulp fibers, synthetic pulp fibers and polyethylene terephthalate fibers, in addition to the separated fibrid copolyester fibers and binders. Additional fibers can impart certain functions or properties such as high mechanical strength, thermal stability, hygroscopicity or hydrophilicity to the nonwoven fabric.

The shell of the separable hollow copolyester fibers of the present invention is such that the hollow copolyester fibers are combined with other fibers such as non-hole or hollow synthetic fibers (such as polyester fibers) or natural fibers such as cotton or wool fibers. Even if used, it can be easily separated into a plurality of fibers, for example thinner than hollow fibers. Thus, the resulting fiber product may exhibit specific properties due to the separated fine copolyester fibers.

For example, when conventional microfine fibers are put into a carding machine, it is difficult for the fibers to pass smoothly to the carding machine.

That is, the carding properties of the separated fine copolyester fibers are very low. When carrying out the carding process with the hollow copolyester fibers of the present invention, only intermittent cracks are formed in the shell of the hollow-fiber along the longitudinal axis of the hollow fiber, and then the hollow fibers are not separated from each other. Is converted into a bundle of separated copolyesters. That is, the separated fine copolyester fibers behave as bundles and thus can pass smoothly through carding machines.

Example

The invention is merely representative and will be further illustrated by the following examples which are in no way intended to limit the scope of the invention.

In the examples, the following tests apply.

(1) intrinsic viscosity

The intrinsic viscosity of a polyester resin is measured using orthochlorophenol as a solvent at 35 degreeC.

(2) the thickness of the fiber

The thickness of the fibers is measured according to Japanese Industrial Standard (JIS) L 1015, 7-5-1A method.

(3) hollow ratio

Using an image-analysis system (trade name: PIAS-2, manufactured by PIAS K. K.), the cross-sectional profile of the individual hollow fibers is enlarged by 500 times, and the cross-sectional area of the fiber and the cross-sectional area of the hollow part of the fiber are measured.

Hollow ratio means the cross-sectional area ratio of a hollow part and a fiber.

(4) intermittent crack

An enlarged micrograph of the hollow fiber side is taken and the photograph is examined to see if intermittent cracks or slits are formed on the edge face of the hollow fiber along the longitudinal axis of the hollow fiber.

(5) thickness of shell

In the enlarged cross-sectional profile of the hollow fiber 500 times, the total cross-sectional area of the hollow fiber and the cross-sectional area of the hollow part are measured, and the thickness of the shell is calculated from the total cross-sectional area of the hollow fiber and the cross-sectional area of the hollow part. The test is applied to 20 hollow fibers to indicate the thickness of the shell as the average value of the 20 test results.

(6) the ratio of each hollow fiber / all hollow fibers separable into four or more fine fibers, respectively

Multiple electron micrographs of the cross-sectional profile of the hollow copolyester are prepared. Regarding the 50 cross-sectional profiles randomly selected from the photographs, the number of cross-sectional profiles with 4 or more cracks capable of separating hollow fibers along the cracks is calculated. The percent of separable hollow copolyester fibers is then calculated based on the 50 hollow copolyester fibers.

(7) Average value of fine fibers separated from hollow copolyester fibers

On the same photograph as used in the test (6), the average of the fine fibers to be separated from the individual hollow copolyester fibers is calculated from the total number of fine fibers to be separated from the 10 individual hollow copolyester fibers selected from those shown in the photograph. do.

(8) crystallinity

The crystallinity of the copolyester resin in the hollow fiber is measured from the wide angle X-ray diffraction image of the fiber.

(010) (010) in-plane crystal size

The crystal size of the (010) in-plane copolyester crystal is measured from half the band width of the (010) in-plane diffraction peak on the wide-angle X-ray diffraction image.

(10) melt-radiative and extensible

(i) The spinning property of a copolyester resin to a hollow fiber is evaluated as follows.

Rating Radiation results

 3 The number of breaks of the filament is less than 0.1 per spinning orifice per day

       The number of adhered filaments is less than 0.1 per spinning orifice per day

 The number of breaks in 2 filaments per day is 0.1 to 0.2 per spinning orifice

       The number of adhered filaments is 0.1 to 0.2 per spinning orifice per day

 The number of breaks in 1 filament per day exceeds 0.2 per spinning orifice

       Sticked filament breakage is greater than 0.2 per spinning orifice per day

As used herein, the term “tacked filament” refers to two or more fused-bonded filaments of each other to form a single filament.

(ii) The elongation of the undrawn hollow filament is evaluated based on the following criteria.

Rating Radiation results

 3 Rolling-winding number due to filament breakage is less than 1 per draw roller

      The number of unstretched filaments is less than 5 per 100,000 filaments

 2 Rolling-winding number due to filament fracture is 1 to 3 per drawing roller

      The number of unstretched filaments ranges from 5 to 10 per 100,000 filaments

 1 rolling-winding due to filament breakage is 3 per day, 3 per drawing roller

      The number of unstretched filaments is 10 per 100,000 filaments

(11) insulation properties

The samples were measured for thermal conductivity in accordance with JIS A 1412 and evaluated in four grades.

Rating Thermal conductivity

 A 0.048 kcal / m

 B 0.048 kcal / m · h · ° C or more, 0.055 kcal / m · h · ° C or less

 C 0.055 kcal / m · h · ° C or more, 0.060 kcal / m · h · ° C or less

 D 0.060 kcal / m

12. Lightweight characteristics of the fabric

Standard specimens are made from 5 pieces (area: 5 cm ² ) of fabric made from hollow fibers having an individual fiber thickness of 1.67 d tex and a hollow ratio of 30%. Overlap five pieces of fabric. The thickness of each piece of the standard fabric is measured and the volume and weight of the standard specimen are measured. The weight of the standard specimen per unit volume was calculated.

Swatches are made from fabrics having the same weight as that of standard fabrics and the weight of the samples per unit volume is calculated.

From the test results, the lightweight properties of the fabric are measured in the following four grades.

Rating Weight per unit volume

 Significantly less than the A standard

 Less than B standard

 C substantially the same as the standard

 Greater than D standard

(13) Feel of fabric, knitted fabric or nonwoven fabric (softness, freshness, drape properties, cushioning properties and compression resistance)

The feel of the woven, knitted or nonwoven fabric was evaluated by sensory evaluation and classified as A to D as follows.

Rating touch

 A excellent

 B good

 C Satisfaction

 D bad

(14) Initial Bulk Properties of Nonwoven Fabrics

Initial bulk properties of nonwoven fabrics are measured in terms of specific volumes in accordance with JIS L 1097.

Knits having dimensions of 20 cm × 20 cm and weights of 40 g (W) are made from a bundle of fibers using a carding machine. The knit is left in the environment for at least 1 hour, then a thick plate having a dimension of 20 cm × 20 cm and a weight of 0.5 g / cm ² is superimposed on the knit, and a bullet having a weight of 2 kg (A) is placed on a thick plate for 30 seconds, the globule (A) is removed from the thick plate, and the remaining knitted fabric and the thick plate are placed for 30 seconds.

Repeat this process three times. After leaving the knit and thick plate removed for 30 seconds, the four corner bottoms (mm) of the thick plate are measured, and the average height (h ₀ ) of the measured heights (mm) is calculated. The specific volume (initial bulkiness) of the knit fabric is calculated according to the following formula:

Initial Bulk Properties (cm 3 / g) = (20 × 20 × h _0/10 ) / W

(15) Initial Compression Bulk Properties of Nonwovens

Initial compressive bulk properties of nonwovens are measured in terms of specific volumes in accordance with JIS L 1097.

The same knitted fabric as mentioned in the test (14) is overlaid on a thick plate having dimensions of 20 cm × 20 cm and a weight of 0.5 g / cm 2 and pressed for 30 seconds with a globule (B) having a weight of 4 kg. Next, the four corner bottoms (mm) of the thick plates are measured, and the average height h ₁ of the measured heights mm is calculated.

The specific volume of the knitted fabric (initial compressive bulkiness) is calculated according to the following formula:

The initial compressed bulkiness (㎤ / g) = (20 × 20 × h 1/10) / W

(16) bending resistance

Use a specimen 2.5 cm wide and 9 cm long. The lower end of the specimen is fixed to a length of 2 cm and a bending force is applied to the specimen with a space of 2 cm from the other end of the specimen. When the specimen is bent at an angle of 90 degrees, the elastic force produced on the specimen is measured with a stress gauge (digital force gauge). The bending resistance of the specimen is expressed as the elastic force per cm of the specimen width.

(17) carding-pass characteristics

A bundle of 2 kg of fibers is passed through a flat carding machine at a carding speed of 50 m / min. The carding properties of the fiber bundles are evaluated in the following four grades.

Rating Carding characteristics

 4 Good carding-passing property, no blockage of carding machine

      And no nep is formed.

 3 Carding blockages and knitted breaks do not occur, and a small amount of nep is formed.

 Two carding blockages do not occur, and a few knit breaks and nep formation occur.

 It is found that carding blockages, knit breaks and nep formation occur.

(18) radioactive

The workability of the hollow copolyester fibers during carding, bonding, roving and fine spinning processes is evaluated in four grades below.

Rating Radioactive

 4 No difficulty during all carding, bonding and spinning and microspinning processes.

 3 No difficulty during carding, bonding and spinning processes.

 2 No difficulty only in carding and bonding process.

 Only carding process is not difficult.

(19) bending strength (kg / ㎠)

The bending strength of the sample is calculated according to the following formula.

Bending Strength (kg / ㎠) = (60 × Bending Resistance (g / cm)) / [Dimensions (mm)] ³

(20) buckling resistance

The specimen having a dimension of 20 cm × 20 cm is bent at a radius of curvature of about 5 mm, while visually observing the curve conditions of the specimen, the curved portion of the specimen is held with a finger and the fixed finger is moved to the position of the curved portion. When the curved portion is kept in a round shape, the buckling resistance of the specimen is excellently evaluated, and when the curved portion is folded angularly, the buckling resistance of the specimen is poorly evaluated.

The buckling resistance is evaluated by four grades.

Rating Buckling resistance

 4 Excellent

 3 good

 2 bad

 1 very bad

21 bending elasticity

A specimen having a 2.5 cm width and a 9 cm length is bent around its transverse centerline such that the thickness of the bent specimen is three times the thickness of the specimen, and the repulsive force generated in the bent specimen is measured with a stress meter. The bending elasticity of the specimen is expressed in repulsive force per cm of specimen width.

The greater the flexural elasticity, the greater the applicability of the specimen to artificial leather.

(22) bend durability

Flexural durability of the specimen is measured according to JIS K 6505,525.

(23) breaking length

The breaking length of the sample is measured according to the test method for elongation strength of paper and cardboard according to JIS P 8113.

24. tear strength

The tear strength of the sample is measured according to JIS L 1096.

Example 1

1600 g / min extrusion of polyethylene terephthalate copolymer resin containing 4.5 mol% of copolymerized 5-sodium sulfoisophthalic acid component (SIP), having an inherent viscosity of 0.45 and mixed with 0.07 wt% titanium dioxide Melt-extruded into a melt spinneret with 2000 hollow filament-forming nozzles at a polymerization temperature of 268 ° C. and cooled-solidified the extruded hollow filament-like copolyester resin melt stream and at a winding rate of 1800 m / sec. Wound up. The unstretched hollow copolyester filaments obtained had individual filament thicknesses of 4.44 d tex and hollow ratios of 50/100.

During the melt-spinning process, in the heating zone located 0 to 50 mm below the spinner, towards the extruded hollow filamentous copolyester resin melt stream, at a 35 degree elevation angle from the right angle to the transverse path of the hollow filament stream, Hot air was blown at a rate of 3.5 m / sec at 200 ° C.

Subsequently, the hollow filamentous stream passing through the heating zone is passed under a heating zone and passed through a buffer zone having a length of 100 mm, and then in a cooling zone located under the buffer zone and having a length of 250 mm, a 25 ° C. temperature Cold air was blown toward the hollow filamentary copolyester resin melt stream at a rate of 3.5 m / sec at to solidify the hollow filamentous copolyester resin melt stream into hollow copolyester filaments.

Drawing the resulting unstretched hollow copolyester filament in a single step in hot water at a draw ratio of 2.80 at a temperature of 65 ° C .; Heat treatment under tension at a temperature of 140 ° C. using a heating roller; Crimp using a mechanical crimp device with a crimp number of 12 crimps / 25 mm; Heat setting under hot air at a temperature of 120 ° C .; And 51 mm long.

The resulting hollow copolyester staple fibers had an individual fiber thickness of 1.67 d tex and a hollow ratio of 50/100, with several cracks extending intermittently along the longitudinal axis of the fiber.

The test results are shown in Table 1.

Examples 2 and 3 and Comparative Examples 1-5

In each of Examples 2 and 3 and Comparative Examples 1 to 5, an unstretched hollow copolyester filament was prepared in the same manner as in Example 1 except that the blowing procedure and cooling procedure for hot air were carried out under the conditions shown in Table 1. .

After the unstretched hollow copolyester filaments were drawn and heat treated under the conditions shown in Table 1, the stretched and heat treated hollow copolyester filaments were crimped and cut in the manner shown in Table 1.

The test results are shown in Table 1.

Examples 4-7 and Comparative Examples 6-7

In each of Examples 4 to 7 and Comparative Examples 6 to 7, hollow copolyester staple fibers (fiber length: 38 to 100 mm) having the properties shown in Table 2 were spun by ring spinning to give a twist number of 17.1 turns. Spun yarn of / 25 mm and British cotton yarn count 30 was prepared.

Spun yarn was woven to produce plain weave fabrics of 87 yarn / 25 mm in warp density, 68 yarn / 25 mm in weft density, and 127 mm in width. The fabric was refined and then dyed with disperse dyes.

In Example 7, plain weave fabrics were made from hollow copolyester staple fibers and cotton fibers in a weight ratio of 50:50.

The properties of the cloth are shown in Table 2.

Examples 8 to 10 and Comparative Examples 8 and 9

In each of Examples 8 to 10 and Comparative Examples 8 and 9, a high shrinkage hollow copolyester staple fiber (fiber length: 38 to 64 mm) and a self-expansion hollow copolyester staple fiber (fiber length) having the properties shown in Table 3 : 38 to 64 mm) was mixed at the mixing weight ratio shown in Table 3. The hollow staple fiber mixture was carded to form a mixed hollow fiber web. Using a needle loom (fiber rocker room) with punching needles, each one having a 40th regular barb, the needle-punching procedure was carried out at a punching density of 800 punch / cm ² . A nonwoven fabric having a basis weight of 157 g / m ² was prepared.

The nonwoven fabric was immersed in hot water at 68 ° C. for 2 minutes to shrink the nonwoven fabric at an area shrinkage of 35%. The shrunken fabric was vacuum dewatered and dried at a temperature of 50 ° C. for 5 minutes. A dried nonwoven fabric having a basis weight of 242 g / m ² was obtained. A nonwoven fabric was inserted between a 60 mesh stainless steel mesh belt and a heated metal drum at a temperature of 180 ° C. for 60 seconds to obtain a nonwoven fabric having a thickness of 1.2 mm and a bulk density of 0.202 g / cm ³ .

An impregnation liquid (trade name: CRYSBON MP-185, manufactured by DAINIPPON INKIKAGAKUKOG.K. K.), containing 100 parts by weight of a 12 parts by weight solution of the polyurethane resin in dimethylformamide, mixed with 5 parts by weight of carbon black was uniformly impregnated with the nonwoven fabric. Subsequently, the impregnated nonwoven fabric is pressed with a pair of pressing rolls, and then immersed in hot water having a temperature of 40 ° C. to coagulate the impregnation solution contained in the nonwoven fabric with water to the extent that substantially no solvent remains in the nonwoven fabric impregnated with the resin. Washed and finally dried. I got an artificial leather.

The test results are shown in Table 3.

Examples 11-15 and Comparative Examples 10 and 11

In each of Examples 11 to 15 and Comparative Examples 10 and 11, hollow copolyester staple fibers (fiber length: 51 mm) having the properties shown in Table 4 were subjected to carding to form a knitted fabric. From the knitted fabric, the nonwoven fabric of the basis weight 60g / m <^2> was obtained.

Table 4 shows the test results of the nonwoven fabric.

Examples 16-19 and Comparative Examples 12 and 13

The same non-crimped detachable hollow copolyester fibers having a thickness of 1.67 d tex, 5 mm in length, 50% in hollow ratio, 30% in crystallinity, 8.5 nm in crystal size, and intermittent cracking, as described in Example 1 Using a disc refiner, fiber separation was performed in water having a 1/100 liquid ratio (fiber / water weight ratio) to obtain an aqueous slurry of separated fibrid fibers.

(1) Aqueous separated fibrid fiber slurry (1) has a heat adhesion temperature of about 120 ° C., and is in a side-by-side form of terephthalic acid / isophthalic acid / ethylene glycol / diethylene glycol copolyester portion and polybutylene terephthalate portion A conjugate fiber composed of a composite fiber, having a thickness of 1.67 d tex, a fiber length of 5 mm, and a crimp number of 0; And (2) an additional fiber consisting of non-porous polyester fiber having a thickness of 0.56 d tex, a fiber length of 5 mm and a crimp number of zero.

Binder fiber (1) and addition fiber (2) were used in the amounts shown in Table 5, respectively.

The resulting aqueous mixed fiber slurry is subjected to a paper forming procedure; The resulting wet-deposited nonwoven sheet is dried by a Yankee dryer; The dried sheet was subjected to a heat tacking process at 120 ° C. Wet-deposited nonwovens having a basis weight of about 50 g / m 2 were obtained. The test results are shown in Table 5.

Example Number Example Comparative example 16 17 18 19 12 13 Ingredient fiber Separated fibrid fibers 80 50 30 95 20 Additional Polyester Fibers - 30 50 80 60 Binder Composite Fiber 20 20 20 5 20 20 Nonwovens Properties Break length (km) 0.12 0.14 0.16 0.05 0.20 0.28 Final elongation (%) 4.1 5.5 6.8 10.7 6.1 7.8 Tear strength (g) 34 36 42 13 52 45 Soft touch 3 3 3 4 One 2

In the separable hollow copolyester fibers of the present invention, the shell has a crack extending intermittently substantially along the longitudinal axis of the hollow fiber, which can be easily separated into a plurality of fine fibers, in particular ultrafine fibers along the crack. When the separated fine fibers are used in a woven or knitted fabric, the resulting fabric exhibits high thermal insulation properties and a soft hand, and when the separated fine fibers are used in the base sheet of artificial leather, the resulting artificial leather It is advantageous in that it exhibits a very soft touch and reinforced lightweight properties. When the separated fine copolyester fibers are used in nonwovens, the resulting nonwovens exhibit reinforced lightweight properties, thermal insulation properties and a soft hand. In particular, when paper forming processing is applied to the separated fine copolyester fibers, the resulting wet-deposited nonwoven has good surface properties even when the nonwoven has a relatively low basis weight.

Claims (12)

(A) one or more hollow portions extending along the longitudinal axis of the hollow copolyester fibers and (B) extending along the longitudinal axis of the hollow copolyester fibers, surrounding the hollow portions, containing terephthalic acid and one or more sulfonate groups A shell comprising a dicarboxylic acid component comprising dicarboxylic acid in an amount of 1 to 6 mol% based on the total molar amount of the dicarboxylic acid component, and a copolyester of a diol component comprising ethylene glycol. Detachable hollow copolyester fibers, Hollow copolyester fibers have (1) a thickness of 0.56 to 8.89 d tex, (2) a total cross sectional area ratio of the hollow portion to the total cross sectional area of the individual fibers 25/100 to 85/100, and (3) a degree of crystallinity of the copolyester 20 to 30 % And (4) a crystal size in the (010) plane of the copolyester of 4.0 to 8.7 nm, The shell of the hollow copolyester fiber has a large number of randomly located cracks in the shell that extend intermittently along the longitudinal axis of the hollow copolyester fiber, thereby applying mechanical force to the shell of the hollow copolyester fiber. Detachable hollow copolyester fibers that can separate into a plurality of fine fibers when applied. The method of claim 1, wherein from 90 to 100% of the hollow copolyester fibers, when applying a mechanical force to each of the shells of the hollow copolyester fibers, each shell portion is separable, which can be separated into 4 to 20 fine fibers Hollow copolyester fibers. The detachable hollow copolyester fiber of claim 1, wherein the shell has an average thickness of 1 to 5 μm. A separated fine copolyester fiber made from the separable hollow copolyester fiber by applying mechanical force to the shell of the separable hollow copolyester fiber of claim 1. A fabric comprising the separated fine copolyester fibers of claim 4. 6. The fabric of claim 5 wherein the separated fine copolyester fibers are contained in an amount of 20 to 100 percent by weight, based on the total weight of all fibers contained in the fabric. A synthetic leather comprising a substrate sheet containing the separated fine copolyester fibers of claim 4 and a synthetic resin impregnated in the substrate sheet. 8. The artificial leather according to claim 7, wherein the separated fine copolyester fibers are present in the substrate sheet in an amount of 20 to 100% by weight. A nonwoven comprising the separated fine copolyester fibers of claim 4 and comprising a plurality of interlaced fibers. 10. The nonwoven fabric of claim 9, wherein the separated fine copolyester fibers are present from 30 to 100 weight percent based on the total weight of fibers contained in the nonwoven fabric. A knitted fabric comprising the separated fine copolyester fibers of claim 4. The knitted fabric according to claim 11, wherein the separated fine copolyester fibers are contained in an amount of 20 to 100% by weight based on the total weight of all fibers contained in the knitted fabric.

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