JP5386400B2 - Dyeing fiber structure excellent in sublimation fastness and method for producing the same - Google Patents

Description

  The present invention relates to a dyed fiber structure having high sublimation fastness and excellent uniformity of dyeing, and a method for producing the same. The dyed fiber structure is preferably used, for example, as a base for artificial leather.

  Polyester fibers are hydrophobic, highly crystalline, and difficult to dye because they are dense. For this reason, polyester fibers are usually dyed using disperse dyes under high temperature and high pressure conditions of around 130 ° C. in order to loosen the bonds between the polyester molecular chains and make the disperse dyes easily diffuse into the fibers. In order to obtain high-temperature and high-pressure conditions, it is necessary to use a sealed and pressure-resistant container, and it is difficult to say that this dyeing method is industrially advantageous in terms of energy. In addition, as a dyeing method using a disperse dye, a method in which a cationic dyeable group is contained in a polyester molecule and dyed with a cationic dye is known, but the kind of dye is limited to a basic dye, and there is calmness. There was a problem that it was difficult to obtain a vivid color with a deep tone.

  It is known to modify the polyester to improve the dyeability of the polyester fiber. For example, Patent Document 1 manufactures polyester fibers for mixing with poly (ethylene terephthalate) and polyethylene glycol to obtain mixed dyed products by mixing with polyamide fibers that can be dyed at normal pressure and have good dyeability. Further, it is described that the dyeability is improved by making the cross section of the polyester fiber W-shaped and making the flatness (ratio of the major axis and minor axis of the ellipse circumscribing the section) within a specific range.

  However, the technique described in Patent Document 1 requires polyester fibers to have a special geometric shape, which is difficult to say in terms of production. Moreover, even if the dyeability is improved, the dyes that can dye the polyester fiber are limited to disperse dyes. Disperse dyes have high sublimation properties. Therefore, when a structure containing polyester fibers dyed with disperse dyes is processed by a high temperature molding method such as thermoforming, the disperse dyes sublimate and the resulting product becomes non-uniformly dyed.

  Patent Document 2 proposes a method in which a copolymer of an aromatic vinyl compound and a vinylamine equivalent is present on the surface of a fiber and dyed at a temperature of 50 ° C. or higher using an acid dye after acid treatment. However, in this method, it is necessary to immerse the fiber product in water and perform the two-stage reaction at a high temperature of 90 ° C. for 4 hours or more, which is problematic in terms of productivity and safety. In addition, if the polyester fiber is thicker than 7 decitex, the influence on the physical properties is limited to the minimum, but when applied to the ultrafine fibers, the deterioration of the physical properties due to deterioration cannot be avoided. Further, since the aromatic vinyl compound and vinylamine equivalent are copolymerized on the fiber surface and the fiber is coated with the copolymer film, the thickness of the film is determined by the thickness of the fiber, the shape of the fiber structure, and the density. It tends to be non-uniform due to the influence and uneven dyeing easily occurs. In addition, a remarkable dark color effect was not obtained with ultrafine fibers of 0.001 to 2 dtex. Furthermore, problems of gas yellowing and fading caused by unreacted raw materials, oligomers of aromatic vinyl compounds and vinylamine equivalents are unavoidable, and the use of products is limited.

JP 2005-344242 A Japanese Patent Laid-Open No. 10-140589

  As described above, conventionally, dyes capable of dyeing polyester fibers are practically limited to disperse dyes. However, it is necessary to dye polyester fibers with disperse dyes under severe conditions of high temperature and high pressure. In addition, the polyester fibers dyed with disperse dyes have insufficient sublimation fastness, and there is a disadvantage that the dyeing of products from which disperse dyes can partially sublimate during high-temperature molding is uneven. Therefore, a fiber structure composed of polyester fibers dyed with a disperse dye is not suitable for high temperature molding. Further, when the fiber structure is impregnated with a polymer elastic body, the polymer dye that is non-dyeing to the disperse dye absorbs a large amount of the disperse dye. Accordingly, it is necessary to wash away the disperse dye absorbed after the dyeing treatment, and the use efficiency of the disperse dye is poor. As described above, there is an industrially inconvenient problem in dyeing polyester fibers with disperse dyes.

  An object of the present invention is to solve the above-mentioned problems, and to provide a dyed fiber structure having high sublimation fastness and excellent dyeing uniformity even after high-temperature molding processing, and a method for producing the same.

  It is known that an acid dye containing a metal-containing dye (metal complex dye) exhibits good dyeability, excellent light fastness and sublimation fastness. However, acid dyes cannot dye polyester fibers, acrylic fibers, polyolefin fibers and the like. As a result of intensive research, the present inventors have attached an acid dye-dyeable resin in the form of fine particles on the fiber surface of an acid dye non-dye resin such as polyester resin, acrylic resin, olefin resin, etc. It has been found that by dyeing a dyeable resin with an acid dye, the fibers of the non-acidic dyeable resin are indirectly dyed with the acid dye.

  In addition, conventional artificial leather that has been impregnated with an acid dye-dyeable resin such as polyurethane in the interfiber spaces and distributed in a network form can be dyed with an acid dye, even if dyed with an acid dye. Only by selective exhaustion, the fiber was not colored, and only a melange-like non-uniform appearance was obtained. However, by attaching the acid dye dyeable resin in the form of fine particles without forming a network on the fiber surface of the acid dye non-dyeable resin, surprisingly, even with a small amount of dye used, a sufficient concentration can be obtained uniformly. It was found that it can be dyed.

  Furthermore, it has been found that the obtained dyed fiber exhibits good sublimation fastness and that the dyeing can be kept uniform even after the fiber structure containing the dyed fiber is processed by high temperature molding. The present invention is based on these findings.

  That is, the present invention includes a fiber of an acid dye non-dyeable resin, and the surface of the fiber of the acid dye non-dye resin is 0.01 to 20% by mass with respect to the fiber of the acid dye non-dye resin. Provided is a dyed fiber structure in which an acid dye-dyeable resin is attached in fine particles and the acid dye-dyeable resin is dyed with an acid dye.

Furthermore, the present invention provides (1) a process of producing a fiber web from fibers of a non-acidic dye dyeable resin,
(2) A step of applying an entanglement treatment to the fiber web to produce an entangled nonwoven fabric;
(3) A step of imparting 0.01 to 20% by mass of an acid dye-dyeable resin to the fiber, and (4) dyeing the acid dye-dyeable resin with an acid dye. A method for producing a dyed fiber structure in which the steps are sequentially performed is provided.

Furthermore, the present invention provides (1) a process for producing a fiber web from fibers capable of forming ultrafine fibers of an acid dye non-dyeable resin,
(2) The fiber web is subjected to an entanglement process to produce an entangled web, and then fibers capable of forming ultrafine fibers in the entangled web are converted into a fiber bundle of ultrafine fibers of an acid dye non-dyeable resin. And manufacturing the entangled nonwoven fabric,
(3) A step of imparting 0.01 to 20% by mass of an acid dye-dyeable resin to the ultrafine fiber to the entangled nonwoven fabric; and (4) Dyeing the acid dye-dyeable resin with an acid dye. The manufacturing method of the dyeing fiber structure which performs the process of carrying out sequentially is provided.

  According to the present invention, it is possible to indirectly dye polyester fibers that could not be dyed with an acid dye typified by a metal-containing dye or the like. The resulting dyed fiber structure exhibits high sublimation fastness and extremely good dyeing uniformity even after processing by high temperature molding. Since the above effect can be sufficiently obtained with a small amount of dyeable acid dyeable resin, it is an economical and environmentally superior dyeing method.

Scanning electron micrograph of the cross-section of the fiber structure of the present invention showing that the metal-containing dye-dyeable resin is finely attached on the ultrafine fibers of the acid dye non-dyeable resin (polyester resin) (1000 times) ). It is a scanning electron micrograph (300 times) of the cross section of the fiber structure described in Comparative Example 1 showing a state in which a structure in which a polyester ultrafine fiber entanglement is impregnated with a polymer elastic body is dyed with a conventional disperse dye.

  Hereinafter, the dyed fiber structure of the present invention will be described with reference to its production method.

The dyed fiber structure of the present invention has the following sequential steps:
(1) a step of producing a fiber web from non-acidic dyeable resin fibers;
(2) A step of applying an entanglement treatment to the fiber web to produce an entangled nonwoven fabric;
(3) A step of imparting 0.01 to 20% by mass of an acid dye-dyeable resin to the fiber, and (4) dyeing the acid dye-dyeable resin with an acid dye. Process or the following sequential process:
(1) A step of producing a fiber web from fibers capable of forming ultrafine fibers of an acid dye non-dyeable resin,
(2) The fiber web is subjected to an entanglement process to produce an entangled web, and then fibers capable of forming ultrafine fibers in the entangled web are converted into a fiber bundle of ultrafine fibers of an acid dye non-dyeable resin. And manufacturing the entangled nonwoven fabric,
(3) A step of imparting 0.01 to 20% by mass of an acid dye-dyeable resin to the ultrafine fiber to the entangled nonwoven fabric; and (4) Dyeing the acid dye-dyeable resin with an acid dye. It can manufacture by the process to do.
Hereinafter, each process is explained in full detail.

  In the step (1), a fiber web is manufactured from fibers of a non-acidic dyeable resin.

  The resin forming the fiber is at least one acid dye non-dyeable resin selected from the group consisting of a polyester resin, an acrylic resin, and an olefin resin. Examples of the polyester resin include polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), modified polyesters thereof (for example, isophthalic acid-modified polyesters having a degree of modification of 1 to 15 mol%), polyester elastomers, and the like. And known fiber-forming water-insoluble thermoplastic polyester resins. Examples of the acrylic resin include water-insoluble homopolymers and copolymers of acrylic compounds such as acrylic acid and esters thereof, acrylamide, acrylonitrile, methacrylic acid and esters thereof, and methacrylamide. Examples of the olefin resin include water-insoluble homopolymers and copolymers of ethylene, propylene, butene, methylpentene, and chlorinated olefins. Polyester resins such as PET, PTT, PBT, and these modified polyesters are easily shrunk by heat treatment, have a solid texture, and have practical properties such as wear resistance, light resistance, and form stability and are colored. This is particularly preferable in that a fiber structure and an artificial leather product having high fiber density and excellent color developability can be obtained.

  The melting point of the acid dye non-dyeable resin is preferably 160 ° C. or higher, more preferably 180 to 330 ° C. and crystalline. The melting point was determined by the method described later. A colorant, an ultraviolet absorber, a heat stabilizer, a deodorant, a fungicide, an antibacterial agent, various stabilizers, and the like may be added to the island component polymer.

  The fiber can be spun by at least one acid dye non-dyeable resin by a known method. For example, melt spinning in which a resin is melted at a temperature equal to or higher than the melting point and extruded from an extruder to produce a yarn, dry solution spinning in which a polymer solution is extruded from pores and a solvent is evaporated, and wet processing in which a polymer solution is spun into a non-solvent. It can be spun by a solution spinning method. The fiber may be a normal fine fiber or an ultrafine fiber, and the single fiber fineness is preferably 0.1 to 20 dtex in view of the production method and the physical properties of the resulting fiber structure. In order to distinguish from a fiber obtained by ultrafinening a composite fiber such as a sea-island type fiber, which will be described later, in the present invention, the fiber obtained as described above is referred to as a directly spun fiber.

The long fibers obtained as described above are stretched and crimped, then cut into a desired fiber length (18 to 110 mm), stapled, and formed into a short fiber web using a card, a cross wrapper, a random webber or the like. May be. Also, immediately after discharging the fiber-forming polymer from the melt spinning nozzle, it is possible to use a method such as a so-called melt-blowing method or flash spinning, which blows away with a high-speed gas to thin the fiber, and uses an electrospinning method or a papermaking method. Nanofibers may be created. Furthermore, the long fiber spun by the spunbond method or the like may be deposited on a collection surface such as a moving net without cutting to form a long fiber web composed of substantially unstretched long fibers. If necessary, the obtained fiber web (short fiber web, long fiber web) is partially pressed by a press (temperature: 30 to 120 ° C., linear pressure: 1 to 10000 N / mm) to stabilize the form. You may let them. The basis weight of the obtained fiber web is preferably 10 to 1000 g / m ² .

  The long fiber web manufacturing method is advantageous in production because it does not require a series of large equipment such as a raw cotton supply device, a fiber opening device, and a card machine, which are essential in the short fiber web manufacturing method. In addition, the artificial leather obtained by using the dyed fiber structure obtained from the long fiber web is composed of continuous fibers having high continuity, so that the strength and the like of the short leather web and the artificial leather manufactured using the short fiber web are increased. Also superior in physical properties. The short fiber web and the long fiber web are selected in consideration of the performance required for the final product.

  In the present invention, the long fiber is a fiber having a fiber length longer than a short fiber having a fiber length of usually about 3 to 80 mm, and means a fiber that is not intentionally cut like a short fiber. For example, the fiber length of the long fiber before ultrafinening is preferably 100 mm or more, and can be produced in a technical manner and has a fiber length of several meters, several hundreds of meters, several kilometers or more as long as it is not physically cut. It may be.

  Instead of using directly spun fibers (usually fine fibers and ultrafine fibers), a fiber web is produced using fibers (ultrafine fiber-forming fibers) that can be converted into ultrafine fibers of non-acid dyeable resin, and the subsequent process , The ultrafine fiber-forming fiber may be converted into a fiber bundle of ultrafine fibers of non-acidic dye-resinable resin.

  Ultrafine fiber forming fibers include sea-island fibers, multi-layer laminated fibers, radial laminated fibers, etc., but sea-island fibers have little fiber damage during needle punching, and the fineness of ultrafine fibers is uniform. Is preferable. Hereinafter, although an example using sea-island type fibers as the ultrafine fiber-forming fibers will be described, the following steps may be performed using other ultrafine fiber-forming fibers such as multilayer laminated fibers and radial laminated fibers. .

  The sea-island fiber is a multicomponent composite fiber composed of at least two types of polymers, and a different type of island component polymer (acid dye non-dyeing resin) is dispersed in the sea component polymer (removable polymer). Has a cross section. The sea-island fibers are formed by extracting or decomposing and removing the sea component polymer after impregnating the acid dye-dyeable resin after forming the entangled web. It is converted into a bundle of collected fibers. In addition, sea-island fibers in which sea components and island components are reversed from the above, that is, sea-island fibers are entangled using sea-island fibers in which the sea component polymer is a non-acidic dye dye resin and the island component polymer is a removable polymer. A web may be formed. By removing the island component polymer by extracting or decomposing it before impregnating the acid dyeable resin, the sea-island fiber is converted into a porous hollow fiber made of the remaining sea component polymer.

  Similar to the resin forming the fiber, the island component polymer is at least one acid dye non-dyeing resin selected from the group consisting of polyester resin, acrylic resin and olefin resin. Details of these resins are as described above, and the description is omitted here for the sake of brevity.

  When the sea-island type fiber is converted into a fiber bundle of ultrafine fibers, the sea component polymer is extracted or decomposed and removed by a solvent or a decomposing agent. Accordingly, the sea component polymer needs to be more soluble in a solvent or decomposable by a decomposing agent than the island component polymer. From the viewpoint of spinning stability of the sea-island fiber, it is preferable that the affinity with the island component polymer is small and the melt viscosity and / or the surface tension is smaller than the island component polymer under the spinning conditions. As long as these conditions are satisfied, the sea component polymer is not particularly limited. For example, polyethylene, polypropylene, polystyrene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, styrene-ethylene copolymer, styrene-acrylic copolymer are used. A polymer, an easily alkali-decomposable modified polyester, a polyvinyl alcohol resin, and the like are preferably used. Since a dyed fiber structure can be produced without using an organic solvent, it is particularly preferable to use water-soluble thermoplastic polyvinyl alcohol (water-soluble PVA) as the sea component polymer.

The viscosity average polymerization degree of water-soluble PVA (hereinafter, simply referred to as polymerization degree) is preferably 200 to 500, more preferably 230 to 470, and further preferably 250 to 450. When the degree of polymerization is 200 or more, the melt viscosity is moderate and it is easy to combine with the island component polymer. When the degree of polymerization is 500 or less, it is possible to avoid a problem that it is difficult to discharge the resin from the spinning nozzle because the melt viscosity is too high. By using so-called low polymerization degree PVA having a polymerization degree of 500 or less, there is also an advantage that the dissolution rate is increased when dissolving with hot water. The degree of polymerization (P) of the water-soluble PVA is measured according to JIS-K6726. That is, after re-saponifying and purifying water-soluble PVA, it is obtained from the intrinsic viscosity [η] measured in water at 30 ° C. by the following equation.
P = ([η] 10 ³ /8.29) ^{(1 / 0.62)}

  The saponification degree of the water-soluble PVA is preferably 90 to 99.99 mol%, more preferably 93 to 99.98 mol%, further preferably 94 to 99.97 mol%, and particularly preferably 96 to 99.96 mol%. . When the degree of saponification is 90 mol% or more, thermal stability is good, satisfactory melt spinning can be performed without thermal decomposition or gelation, and biodegradability is also good. Further, the water-solubility is not lowered by the copolymerization monomer described later, and it becomes easy to make it ultrafine. Water-soluble PVA having a degree of saponification of greater than 99.99 mol% is difficult to produce stably.

  160-230 degreeC is preferable, as for melting | fusing point (Tm) of water-soluble PVA, 170-227 degreeC is more preferable, 175-224 degreeC is further more preferable, 180-220 degreeC is especially preferable. When the melting point is 160 ° C. or higher, the crystallinity is not lowered and the fiber strength is not lowered, and it is also possible to prevent the fiber from becoming difficult due to poor thermal stability. When the melting point is 230 ° C. or lower, melt spinning can be performed at a temperature lower than the decomposition temperature of PVA, and sea-island fibers can be stably produced.

  The water-soluble PVA can be obtained by saponifying a resin mainly containing vinyl ester units. Vinyl compound monomers for forming vinyl ester units include vinyl formate, vinyl acetate, vinyl propionate, vinyl valenate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl benzoate, vinyl pivalate and Examples include vinyl versatate, and among these, vinyl acetate is preferable from the viewpoint of easily obtaining water-soluble PVA.

  The water-soluble PVA may be a homo-PVA or a modified PVA into which copolymer units are introduced, but it is preferable to use a modified PVA from the viewpoint of melt spinnability, water-solubility and fiber properties. Examples of the comonomer include α-olefins having 4 or less carbon atoms such as ethylene, propylene, 1-butene, and isobutene, methyl vinyl ether, and ethyl vinyl ether from the viewpoints of copolymerizability, melt spinnability, and water solubility of the fiber. , Vinyl ethers such as n-propyl vinyl ether, isopropyl vinyl ether and n-butyl vinyl ether are preferred. The amount of units derived from α-olefins having 4 or less carbon atoms and / or vinyl ethers is preferably 1 to 20 mol%, more preferably 4 to 15 mol%, and more preferably 6 to 13 mol% of the modified PVA structural unit. Further preferred. Further, when the comonomer is ethylene, the fiber physical properties are improved, and therefore modified PVA containing ethylene units preferably in an amount of 4 to 15 mol%, more preferably 6 to 13 mol% is preferable.

  Water-soluble PVA is produced by a known method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method, or an emulsion polymerization method. Among these, a bulk polymerization method or a solution polymerization method in which polymerization is performed without solvent or in a solvent such as alcohol is preferable. Examples of the solution polymerization solvent include lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol. Examples of the initiator used for copolymerization include a, a′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethyl-valeronitrile), benzoyl peroxide, and n-propyl peroxycarbonate. And known initiators such as azo initiators or peroxide initiators. Although there is no restriction | limiting in particular about superposition | polymerization temperature, The range of 0-150 degreeC is suitable.

  The sea-island fiber is melt-spun by extruding the sea component polymer and the island component polymer from a composite spinning die. The spinning temperature (die temperature) is preferably 180 to 350 ° C. After the molten sea-island fiber discharged from the die is cooled by a cooling device, a suction device such as an air jet nozzle is used, and a speed corresponding to a take-up speed of 1000 to 6000 m / min is obtained so as to achieve a desired fineness. It can be obtained by pulling with high-speed airflow. Even when using ultrafine fiber-forming fibers, long fibers are drawn and crimped, then cut into staples of any fiber length (18 to 110 mm), stapled, and short fibers using a card, cross wrapper, random webber, etc. It may be a web. In addition, the sea-island long fibers spun by the spunbond method (ultra-fine long fiber forming fibers) are deposited on a collecting surface such as a mobile net without being cut, and are made of substantially unstretched long fibers. It may be a long fiber web. If necessary, the obtained fiber web (short fiber web, long fiber web) is partially pressed by a press (temperature: 30 to 120 ° C., linear pressure: 1 to 10000 N / mm) to stabilize the form. You may let them.

The average cross-sectional area of the sea-island fiber is preferably 30 to 800 μm ² . In the cross section of the sea-island fiber, the average area ratio (corresponding to the polymer volume ratio) between the sea component polymer and the island component polymer is preferably 5/95 to 70/30. The basis weight of the fiber web obtained using sea-island fibers is preferably 10 to 1000 g / m ² .

  In the step (2), the fiber web of directly spun fibers is subjected to an entanglement treatment to obtain an entangled nonwoven fabric. When ultrafine fiber-forming fibers are used, an entanglement treatment is performed to form an entangled web, and then the ultrafine fiber-forming fibers are converted into a bundle of ultrafine fibers of acid dye non-dyeable resin to form an entangled nonwoven fabric. obtain.

A fiber web of directly spun fibers is superposed with a plurality of layers using a cross wrapper, if necessary, and then needle punched under the condition that at least one barb penetrates from both sides simultaneously or alternately. Punching density is preferably 300 to 6,000 punches / cm ^2, more preferably 500 to 5,000 punches / cm ^2. When it is within the above range, sufficient entanglement can be obtained, and damage by the needle of the directly spun fiber is small. By the entanglement treatment, the directly spun fibers are three-dimensionally entangled, and the directly spun fibers are present at an average density of 400 to 5000 pieces / mm ² in a cross section parallel to the thickness direction. A densely entangled nonwoven fabric is obtained. The fiber web may be provided with an oil agent at any stage from its production to the entanglement treatment. Moreover, you may make the entangled state of a fiber web more precise | minute by the shrinkage process of immersing in 70-150 degreeC warm water as needed. Alternatively, the spun fibers may be gathered more densely by hot pressing to stabilize the fiber web. The basis weight of the entangled nonwoven fabric is preferably 100 to 3000 g / m ² .

The sea island type fiber web is also entangled in the same manner as described above to obtain an entangled web. A plurality of sea-island-type fiber webs are overlapped as necessary using a cross wrapper or the like, and then needle punched under the condition that at least one barb penetrates from both sides simultaneously or alternately. Punching density is preferably 300 to 6,000 punches / cm ^2, more preferably 500 to 5,000 punches / cm ^2. When it is within the above range, sufficient entanglement is obtained, and the sea island type fiber is less damaged by the needle. By the entanglement treatment, the sea-island fibers are entangled three-dimensionally, and the sea-island fibers are present at an average density of 600 to 4000 / mm ² in a cross section parallel to the thickness direction. A densely entangled web is obtained. You may give an oil agent to the fiber web of a sea-island type fiber in any step from the manufacture to an entanglement process. Moreover, you may make the entanglement state of a fiber web more precise | minute by the shrinkage process of immersing in 70-150 degreeC warm water as needed. Moreover, sea-island type fibers may be gathered more densely by performing a heat press treatment, and the form of the fiber web may be stabilized. The basis weight of the entangled web is preferably 100 to 2000 g / m ² .

  When sea-island type fibers are used, the ultra-fine fiber-forming fibers (sea-island type fibers) are converted into ultra-fine fiber bundles of acid dye non-dyeable resin by removing the sea component polymer. A synthetic nonwoven fabric is produced. As a method of removing the sea component polymer, a method of treating the entangled web with a non-solvent or non-decomposing agent of the island component polymer and using the solvent or decomposing agent of the sea component polymer is preferably employed in the present invention. . If the island component polymer is a polyester-based resin and the sea component polymer is polyethylene, an organic solvent such as toluene, trichlorethylene, or tetrachloroethylene is used. If the sea component polymer is water-soluble PVA, warm water is used. An alkaline decomposing agent such as an aqueous solution of sodium hydroxide is used. The removal of the sea component polymer may be performed by a method conventionally employed in the artificial leather production field, and is not particularly limited. In the present invention, the environmental load is small and preferable from the viewpoint of occupational health. Therefore, water-soluble PVA is used as the sea component polymer, and this is used in hot water at 85 to 100 ° C. without using an organic solvent. It is preferable to treat for 600 seconds, extract and remove until the removal rate reaches 95% by mass or more (including 100%), and convert the ultrafine fiber-forming fibers into fiber bundles of ultrafine fibers.

If necessary, before or at the same time as ultrafine fiber forming fiber, the following formula:
[(Area before shrinkage treatment−Area after shrinkage treatment) / Area before shrinkage treatment] × 100
The shrinkage treatment may be performed to increase the density so that the area shrinkage rate represented by is preferably 30% or more, more preferably 30 to 75%. The shape retention is improved by the shrinking treatment, the fiber is prevented from coming off, and the color developability is improved.

  When it is performed before ultra-thinning, the entangled web is preferably contracted in a steam atmosphere. In the shrinkage treatment with water vapor, for example, 30 to 200% by mass of water is given to the entangled web with respect to the sea component, and then the relative humidity is 70% or more, more preferably 90% or more, and the temperature is 60 to 130 ° C. It is preferable to heat-treat for 60 to 600 seconds in a heated steam atmosphere. When the shrinkage treatment is performed under the above conditions, the sea component polymer plasticized with water vapor is compressed and deformed by the shrinkage force of the ultrafine fiber composed of the island component polymer, so that densification becomes easy. Next, the entangled web subjected to the shrinkage treatment is treated in hot water at 85 to 100 ° C., preferably 90 to 100 ° C. for 100 to 600 seconds to dissolve and remove the sea component polymer. Moreover, you may perform a water flow extraction process so that the removal rate of a sea component polymer may be 95 mass% or more. The temperature of the water flow is preferably 80 to 98 ° C., the water flow speed is preferably 2 to 100 m / min, and the treatment time is preferably 1 to 20 minutes.

  As a method for simultaneously performing the shrinkage treatment and the ultra-thinning, for example, after the entangled web is immersed in hot water at 65 to 90 ° C. for 3 to 300 seconds, it is subsequently heated at 85 to 100 ° C., preferably 90 to 100 ° C. The method of processing for 100 to 600 seconds in water is mentioned. In the preceding stage, the sea component polymer is squeezed simultaneously with the shrinkage of the ultrafine fiber-forming fibers. Part of the compressed sea component polymer elutes from the fiber. Therefore, the void formed by the removal of the sea component polymer becomes smaller, so that a denser entangled nonwoven fabric can be obtained.

By the shrinkage treatment (optional) and the removal of the sea component polymer, an entangled nonwoven fabric having a basis weight of preferably 140 to 3000 g / m ² is obtained. The average fineness of the fiber bundle in the entangled nonwoven fabric is 0.5 to 10 dtex, preferably 0.7 to 5 dtex. The average single fiber fineness of the ultrafine fibers is 0.001 to 2 dtex, preferably 0.005 to 0.2 dtex. Within this range, the denseness of the resulting fiber structure and the denseness of the surface layer portion are improved. The number of ultrafine fibers in the fiber bundle is not particularly limited as long as the average single fiber fineness of the ultrafine fibers and the average fineness of the fiber bundle are within the above ranges, but generally 5 to 1000.

  The peel strength when wet of the entangled nonwoven fabric of ultrafine fibers derived from the directly spun fibers or ultrafine fiber-forming fibers obtained as described above is preferably 4 kg / 25 mm or more, and is 4 to 15 kg / 25 mm. It is more preferable. Peel strength is a measure of the degree of three-dimensional entanglement of fiber bundles of fibers or ultrafine fibers. Within the above range, the surface of the entangled nonwoven fabric and the resulting dyed fiber structure and artificial leather is less, and the shape retention is good. In addition, an artificial leather with excellent fulfillment can be obtained. If the peel strength at the time of wetting is within the above range, it is possible to prevent the fibers from coming off and fraying in the subsequent step.

  In step (3), the entangled nonwoven fabric obtained in step (2) is uniformly impregnated with an aqueous emulsion of an acid dye-dyeable resin, or heat is applied to the front and back surfaces of the entangled nonwoven fabric. Then, the acid dye-dyeable resin is transferred to the front and back surfaces, and then solidified in the form of fine particles directly on the surface of the spun fibers or fiber bundles and the ultrafine fibers therein. The acid dye dyeable resin is not particularly limited as long as it is a resin dyed with an acid dye, but a water-emulsifiable polyurethane elastomer and an acrylic elastomer are particularly preferably used.

  As a water-emulsifiable polyurethane elastomer, a polymer polyol, an organic diisocyanate and, if necessary, a chain extender in a desired ratio, are obtained by polymerization by a melt polymerization method, a bulk polymerization method, a solution polymerization method, or the like. These thermoplastic polyurethanes are preferred.

The polymer polyol is selected from known polymer polyols according to the application and required performance. For example, polyether polyols and copolymers thereof such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (methyltetramethylene glycol), poly (methylpentane) diol; polybutylene adipate diol, polybutylene sebacate diol, Polyester polyols such as polyhexamethylene adipate diol, poly (3-methyl-1,5-pentylene adipate) diol, poly (3-methyl-1,5-pentylene sebacate) diol, polycaprolactone diol and the like Polymer: polyhexamethylene carbonate diol (polyhexylene carbonate diol), poly (3-methyl-1,5-pentylene carbonate) diol, polypentamethylene carbonate All, polycarbonate polyols and copolymers thereof, such as polytetramethylene carbonate diol; and polyester carbonate polyols and the like, may be used alone or two or more of them.
The average molecular weight of the polymer polyol is preferably 500 to 3000. Two or more kinds of polymers are used to improve the durability of the dyed fiber structure and artificial leather, such as light fastness, heat fastness, NOx yellowing resistance, sweat resistance, and hydrolysis resistance. It is preferable to use a polyol.

  The organic diisocyanate may be selected from known diisocyanate compounds depending on the application and required performance. For example, aliphatic or alicyclic diisocyanate having no aromatic ring (non-yellowing diisocyanate) such as hexamethylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, hydrogenated methylene diisocyanate (4,4′-dicyclohexylmethane diisocyanate), Aromatic ring diisocyanates such as phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate and the like can be mentioned. In particular, it is preferable to use a non-yellowing diisocyanate because yellowing due to light or heat hardly occurs.

The chain extender may be selected from low molecular compounds having two active hydrogen atoms that are used as chain extenders in the production of known urethane resins depending on the application and required performance. For example, diamines such as hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, piperazine and derivatives thereof, adipic acid dihydrazide, isophthalic acid dihydrazide; triamines such as diethylenetriamine; triethylenetetramine Diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (β-hydroxyethoxy) benzene, 1,4-cyclohexanediol; Examples include triols such as methylolpropane; pentaols such as pentaerythritol; and amino alcohols such as aminoethyl alcohol and aminopropyl alcohol. Is, it is possible to use one or more of these. Among these, it is preferable to use 2 to 4 kinds of hydrazine, piperazine, hexamethylenediamine, isophoronediamine and derivatives thereof, and triamines such as ethylenetriamine in combination. In particular, since hydrazine and its derivatives have an antioxidant effect, durability is improved.
In addition, during the chain extension reaction, together with the chain extender, monoamines such as ethylamine, propylamine, and butylamine; carboxyl group-containing monoamine compounds such as 4-aminobutanoic acid and 6-aminohexanoic acid; methanol, ethanol, propanol, butanol, etc. Monools may be used in combination.

  The soft segment content is 90 to 15% by mass and the hard segment content is 10 to 85% by mass with respect to the total amount of the thermoplastic polyurethane soft segment (polymer diol) and hard segment (organic diisocyanate). Is preferred. When using a chain extender, it is preferable that the usage-amount is 1-50 mass% with respect to the total amount of a soft segment and a hard segment.

  Examples of water-emulsifiable acrylic elastomers include polymers of water-dispersible or water-soluble ethylenically unsaturated monomers comprising, for example, a soft component, a crosslinkable component, a hard component, and other components not belonging to any of these components. Is mentioned.

  The soft component is a component having a glass transition temperature (Tg) of the homopolymer of less than −5 ° C., preferably −90 ° C. or more and less than −5 ° C., and is non-crosslinkable (does not form a crosslink). It is preferable. Examples of the monomer that forms the soft component include ethyl acrylate, n-butyl acrylate, isobutyl acrylate, isopropyl acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) Examples include (meth) acrylic acid derivatives such as lauryl acrylate, stearyl (meth) acrylate, cyclohexyl acrylate, benzyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and the like. Or 2 or more types can be used.

  The hard component is a component whose glass transition temperature (Tg) of the homopolymer exceeds 50 ° C., preferably more than 50 ° C. and 250 ° C. or less, and is non-crosslinkable (does not form a crosslink). Is preferred. Examples of the monomer that forms the hard component include methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, (meth) acrylic acid, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and methacrylic acid. (Meth) acrylic acid derivatives such as 2-hydroxyethyl; aromatic vinyl compounds such as styrene, α-methylstyrene and p-methylstyrene; acrylamides such as (meth) acrylamide and diacetone (meth) acrylamide; maleic acid, Fumaric acid, itaconic acid and their derivatives; heterocyclic vinyl compounds such as vinylpyrrolidone; vinyl compounds such as vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, vinylamide; , Typified by propylene α- olefins, and the like, may be used alone or two or more of them.

  The crosslinkable component is a compound capable of forming a crosslinked structure by reacting with a monofunctional or polyfunctional ethylenically unsaturated monomer unit capable of forming a crosslinked structure, or an ethylenically unsaturated monomer unit introduced into a polymer chain. (Crosslinking agent). Examples of the monofunctional or polyfunctional ethylenically unsaturated monomer include ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and 1,4-butanediol di (meth). Acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, glycerin di (meth) ) Di (meth) acrylates such as acrylate; Tri (meth) acrylates such as trimethylolpropane tri (meth) acrylate and pentaerythritol tri (meth) acrylate; Pentaerythritol tetra (meth) acrylate Tetra (meth) acrylates such as polyfunctional aromatic vinyl compounds such as divinylbenzene and trivinylbenzene; (meth) acrylic acid unsaturated esters such as allyl (meth) acrylate and vinyl (meth) acrylate; 2: 1 addition reaction product of hydroxy-3-phenoxypropyl acrylate and hexamethylene diisocyanate, 2: 1 addition reaction product of pentaerythritol triacrylate and hexamethylene diisocyanate, 2: 1 addition reaction product of glycerol dimethacrylate and tolylene diisocyanate, etc. Urethane acrylate having a molecular weight of 1500 or less; (meth) acrylic acid derivatives having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; (meth) acrylamide, da Acrylamides such as acetone (meth) acrylamide and derivatives thereof; (meth) acrylic acid derivatives having an epoxy group such as glycidyl (meth) acrylate; carboxyl groups such as (meth) acrylic acid, maleic acid, fumaric acid, and itaconic acid And vinyl compounds having an amide group such as vinylamide, and one or more of them can be used.

  Examples of the crosslinking agent include an oxazoline group-containing compound, a carbodiimide group-containing compound, an epoxy group-containing compound, a hydrazine derivative, a hydrazide derivative, a polyisocyanate compound, a polyfunctional block isocyanate compound, and one or more of these Two or more kinds can be used.

  Examples of the monomer that forms the other components of the acrylic elastomer include (methacrylates such as methyl acrylate, n-butyl methacrylate, hydroxypropyl methacrylate, glycidyl (meth) acrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate). ) Acrylic acid derivatives.

  The melting point of the acid dye-dyeable resin is preferably 130 to 240 ° C, and the hot water swelling rate at 130 ° C is 10% or more, preferably 10 to 100%. In general, the higher the hot water swelling rate, the softer the acid dye-dyeable resin, but the weaker the cohesive force in the molecule, the more often it peels off during the subsequent process or use of the product. Adhesion to the bundle and the ultrafine fibers inside it becomes insufficient. Such inconvenience can be avoided if it is within the above range. The hot water swelling rate was determined by the method described later.

  The peak temperature of the loss modulus of the acid dye-dyeable resin is 10 ° C. or lower, preferably −80 ° C. to 10 ° C. When the peak temperature of the loss elastic modulus exceeds 10 ° C., the texture of the artificial leather to be obtained becomes stiff and the mechanical durability such as flex resistance deteriorates. The loss elastic modulus was obtained by the method described later.

  Acid dye use amount 10% owf, bath ratio 1:45, dyeing temperature: 95 ° C., dyeing time: dyeing time: 60 minutes, dyeing amount of acid dye dyeable resin is 30 mg / g or more, preferably 30 It is -100 mg / g, More preferably, it is 40-100 mg / g, More preferably, it is 50-100 mg / g. Since the water-emulsifiable acid dye-dyeable resin has many polar groups (dyeing seats), the exhaust amount is large, the dyeing density can be increased, and the dye can be used efficiently.

  The acid dye dyeable resin is impregnated into the entangled nonwoven fabric as an aqueous emulsion. The content of the acid dye dyeable resin in the aqueous emulsion is preferably 0.1 to 60% by mass. The water-based emulsion of the acid dye dyeable resin has an acid dye dyeable resin amount of 0.01 to 20 with respect to the fiber directly after coagulation, or attached to the surface of the fiber bundle or fiber bundle and the ultrafine fiber in the fiber bundle. It is impregnated so that it becomes mass%, preferably 0.05 to 15 mass%, more preferably 0.1 to 10 mass%. If it is in the said range, acidic dye dyeable resin will adhere to a fiber or fiber bundle surface in fine particle form, sufficient dyeing | staining density | concentration will be obtained, and it can dye | stain uniformly. Moreover, it can avoid that fibers adhere | attach via acid dye dyeable resin. When the above range is exceeded, the acid dye-dyeable resin does not adhere in the form of fine particles on the surface of the fiber or fiber bundle, and continuously adheres to form a network. As a result, uniform dyeing cannot be obtained, the color tone is poor, and a large amount of acid dye is required.

  In the present invention, “attached in the form of fine particles” means that the maximum diameter is 100 μm or less on the surface (on the side surface extending in the length direction) of the directly spun fiber or the fiber bundle and the ultrafine fiber therein as shown in FIG. It shows that the acid dye-dyeable resin particles are scattered in a discontinuous manner without forming a network. The average particle size is preferably 50 μm or less in terms of uniform adhesion, more preferably 10 μm or less, and most preferably 5 μm or less in terms of more uniform adhesion. The size of the attached acid dye dyeable resin particles obtained industrially is affected by the thickness and type of the fibers used, but it is preferable that the average particle diameter is equal to or less than the average diameter of the single fibers of the ultrafine fibers. The lower limit of the maximum length is usually 10 nm.

  Water-based emulsions of acid dyeable resins include penetrants, antifoaming agents, lubricants, water repellents, oil repellents, thickeners, extenders, curing accelerators, antioxidants, UV absorbers, fluorescent agents, An antifungal agent, a foaming agent, a water-soluble polymer compound such as polyvinyl alcohol and carboxymethyl cellulose, a dye, a pigment, and the like may be added.

  The method of impregnating the entangled nonwoven fabric with the aqueous emulsion of the acid dye-dyeable resin is not particularly limited, but for example, the method of uniformly impregnating the entangled nonwoven fabric by dipping etc. The method of making it penetrate | infiltrate uniformly is mentioned. Also, after impregnating the inside of the entangled nonwoven fabric, or after applying it to the front and back surfaces, the acid dye-dyeable resin is migrated to the front and back surfaces, and then solidified, mainly fibers on both surface layers. An acid dye-dyeable resin may be deposited thereon. For example, the front and back surfaces of the entangled nonwoven fabric are preferably heated at 110 to 150 ° C., preferably 0.5 to 30 minutes. Moisture is evaporated from the front and back surfaces by such heating, and the water containing the acid dye dyeable resin is transferred to both surface layers, and the acid dye dyeable resin is present on the fiber in the vicinity of the front and back surfaces. To solidify. Heating for migration is preferably performed by blowing hot air on the front and back surfaces in a drying apparatus or the like. In addition, when the entangled nonwoven fabric is composed of a bundle of ultrafine fibers, before applying the aqueous emulsion of the acid dye-dyeable resin to the entangled nonwoven fabric, relax in a circular dyeing machine at 70 ° C. for 30 minutes, It is preferable that the ultrafine fibers in the fiber bundle are unconstrained and separated by means such as treatment with a combination machine or raising with a raising brush or sandpaper. When an aqueous emulsion is applied after this, the acid dye-dyeable resin adheres finely onto the ultrafine fibers inside the fiber bundle.

  In the step (4), the acid dye-dyeable resin adhering in fine particles onto the directly spun fiber or the fiber bundle and the ultrafine fiber in the fiber bundle is dyed with an acid dye.

An acid dye is an ion which is ionized in a solution and has an organic residue as an anion, and is dyed by an ionic bond between a fiber having basic nitrogen and an acid bath. It can be used for dyeing protein fibers such as silk and wool and nylon, and any known dye can be used as long as it is the above-mentioned dye. For example, Kayanol (registered trademark) series manufactured by Nippon Kayaku Co., Ltd. , Kayanol Milling Series, Suminol (registered trademark) “manufactured by Sumitomo Chemical Co., Ltd.”, etc. Among these, gold-containing dyes in which chromium, cobalt, etc. are coordinated in the dye molecule are more fibers. Is preferable in that it is suitable for fast dyeing.
The metal-containing dye is a complex salt type azo dye in which a metal atom is coordinated to a dye molecule, and a 1: 1 metal-containing dye in which one metal atom and one dye molecule are coordinated. A 1: 2 gold-containing dye is known in which a metal atom and two dye molecules are coordinated. The metal is usually chromium. In order to obtain higher dyeing fastness, it is preferable to use a 1: 2 gold-containing dye. 1: 2 gold-containing dyes include Sumitomo Chemical Co., Ltd. trade name Lanyl (registered trademark) series, Nippon Kayaku Co., Ltd. trade name Kayalan (registered trademark) and Kayalax (registered trademark) series, Mitsui BASF dye ( Product name Acidol (registered trademark) and Lanafast series, product name Aizen (registered trademark) series of Hodogaya Chemical Co., Ltd., product name Isolan (registered trademark) series of Dystar, products of Ciba Specialty Chemicals Name Irgalan (registered trademark) series and Clariant Co., Ltd., trade name Lanasyn (registered trademark) series can be obtained, but other metal-containing dyes can also be used. Hereinafter, description will be made by taking a metal-containing dye as an example.

  Dyeing may be performed according to conventional dyeing conditions for fibers and fabrics using metal-containing dyes. For example, the bath ratio is 1:10 to 1: 100, the amount of the metal-containing dye used is 0.0001 to 50% owf, the dyeing temperature is 70 to 100 ° C., the dyeing time is 20 to 120 minutes, and the pH of the dyeing bath is slightly acidic. It is preferable to carry out under neutral conditions. In the present invention, unlike the dyeing of polyester fibers with conventional disperse dyes, the dyeing can be performed under normal conditions under mild conditions, and the dyeing process is easy.

  The dyeing may be performed in the presence of a dyeing assistant. As dyeing assistants, accelerators that increase the dyeing speed, leveling agents for uniform dyeing, slow dyeing agents that slow down the dyeing speed and eliminate uneven dyeing, and penetrants that help the dye penetrate and diffuse into the fiber , Dye solubilizers that increase the solubility of dyes in dye baths, dye dispersants that increase the dispersibility of dyes in dye baths, fixing agents that increase the fastness of dyed dyes, fiber protection agents, antifoaming agents Etc. These can be appropriately selected from conventionally known drugs, and are used in conventional amounts.

  Examples of the dyeing apparatus that are usually used include a liquid dyeing machine, a wins dyeing machine, a beam dyeing machine, and a zicker dyeing machine.

The dyed fiber structure of the present invention obtained as described above may contain fibers other than the fibers of the metal-containing dye non-dyeing resin, or is formed only of the dyed fibers of the metal-containing dye non-dyeing resin. It may be. The basis weight of the dyed fiber structure is preferably 80 to 3000 g / m ² .

  The dyed fiber structure of the present invention is preferably used as a base material for artificial leather. For example, by applying a resin for the surface coating layer on the surface of the dyed fiber structure under a desired condition by a known method, and further performing processing such as embossing, softening treatment, and dyeing as necessary, Moreover, it can be set as the artificial leather of a tone with silver, or a tone with semi-silver by heating and melting the surface and smoothing the surface. In addition, the surface of the dyed fiber structure can be raised and fluffed, and further softened as necessary to obtain a suede-like or nubuck-like artificial leather. As a method for fluffing, a known method can be used, but it is preferable to buff using sandpaper or a needle cloth. The obtained artificial leather has a uniform color tone as well as excellent appearance, texture and mechanical properties. In addition, because it has high sublimation fastness, it can be processed into various shapes by high-temperature molding without changing the uniform color tone, shoes, various cases, mobile phone holders, home appliance exteriors, molded bags, vehicle interior materials Suitable as a material for products such as competition balls.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. “%” Described in the examples is based on mass unless otherwise specified. Each characteristic was measured by the following method.

(1) Average fineness of fiber The cross-sectional area of the fibers (20 pieces) forming the leather-like sheet was measured with a scanning electron microscope (magnification: several hundred to several thousand times) to obtain the average cross-sectional area. The average fineness was calculated from the average cross-sectional area and the density of the polymer forming the fiber.

(2) Average fineness of fiber bundles An average fiber bundle (20 pieces) selected from the fiber bundles forming the entangled nonwoven fabric is scanned with a scanning electron microscope (magnification: several hundred to several thousand times). The average cross-sectional area was determined by observing and measuring the radius of the circumscribed circle. Assuming that this average cross-sectional area is filled with the polymer forming the fiber, the average fineness of the fiber bundle was calculated from the density of the polymer.

(3) Melting point Using a differential scanning calorimeter (TA3000, manufactured by Mettler), the temperature was raised from room temperature to 300 to 350 ° C. according to the polymer type in a nitrogen atmosphere at a heating rate of 10 ° C./min, and then immediately to room temperature. After cooling, the peak top temperature of the endothermic peak obtained when the temperature was immediately raised again to 300 to 350 ° C. at a temperature rising rate of 10 ° C./min was determined.

(4) Peak temperature of loss elastic modulus An acid dye non-dyeing resin film having a thickness of 200 μm was heat-treated at 130 ° C. for 30 minutes, and a viscoelasticity measuring device (FT Leospectr "DVE-V4" manufactured by Rheology) was used. The measurement was performed at a frequency of 11 Hz and a temperature increase rate of 3 ° C./min, and the peak temperature of the loss modulus was obtained.

(5) Hot water swelling rate at 130 ° C. A 200 μm thick acid dye non-dyeing resin film was hydrothermally treated at 130 ° C. for 60 minutes under pressure, cooled to 50 ° C., and taken out with tweezers. Excess water was wiped off with filter paper and the weight was measured. The ratio of the increased weight to the weight before immersion was taken as the hot water swelling rate.

(6) Exhaust Amount 0.001%, 0.01%, 0.1%, 10% aqueous solution of Kayakalan Black 2BL was prepared, the absorption spectrum was measured, and the maximum absorption wavelength was determined. Next, the relationship between absorbance and concentration at the maximum absorption wavelength was graphed and used as a calibration curve. Next, an acid dye dyeable resin foamed structure was prepared, and 5 g of the foamed structure was dyed at 95 ° C. for 60 minutes at a concentration of 10% owf using a pot dyeing machine having a bath ratio of 1:45. The absorbance of the dyeing residual liquid was measured and converted into a concentration from the calibration curve, and the exhausted amount to the acid dye dyeable resin was calculated.

(7) Apparent density Measured by the method specified in JIS L 1096: 1999 8.10.1.

(8) Peeling strength when wet The surface of a rubber plate having a length of 15 cm, a width of 2.7 cm, and a thickness of 4 mm was buffed with No. 240 sandpaper to sufficiently roughen the surface. A 100: 5 mixed solution of a solvent-based adhesive (US-44) and a cross-linking agent (Dismodule RE) was used as a rough surface of the rubber plate (sheet length direction) 25 cm and a width 2.5 cm test piece It was applied to one side of the glass plate with a length of 12 cm with a glass rod and dried in a dryer at 100 ° C. for 4 minutes. Thereafter, the adhesive-applied portions of the rubber plate and the test piece were bonded together, pressure-bonded with a press roller, and cured at 20 ° C. for 24 hours. After dipping in distilled water for 10 minutes, the ends of the rubber plate and the test piece were each sandwiched between chucks and peeled off at a tensile speed of 50 mm / min with a tensile tester. The average peel strength when wet was determined from the flat portion of the obtained stress-strain curve (SS curve). The result was expressed as an average value of three test pieces.

(9) Content ratio of acid dyeable resin The element obtained from the fiber structure was subjected to elemental analysis to determine the total nitrogen amount. The content ratio was calculated from the total amount of nitrogen obtained, the amount of nitrogen of the acid dye-dyeable resin, and the amount of fibers of the non-acid dye-dyeable resin.

(10) Adhesion State of Acid Dye-Dyeable Resin The cross section of the fiber structure was observed with a scanning electron microscope “S-2100 Hitachi Scanning Electron Microscope” (magnification 100 to 2000) at 10 or more locations.

(11) Evaluation of leveling property Ten persons engaged in dyeing technology were visually judged according to the following criteria, and the average of the total score was evaluated.
3 points: Very uniformly dyed.
2 points: Although there is a slight lack of leveling, there is no problem as a commercial product.
One point: It is dye | stained unevenly and lacks in commercial property.

Production of water-soluble thermoplastic polyvinyl alcohol resin 2100 kg of vinyl acetate and 31.0 kg of methanol were placed in a 100 L pressure reactor equipped with a stirrer, nitrogen inlet, ethylene inlet and initiator addition port, and the temperature was adjusted to 60 ° C. After raising the temperature, the system was purged with nitrogen by nitrogen bubbling for 30 minutes. Next, ethylene was introduced so that the reactor pressure was 5.9 kgf / cm ² . 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile) (initiator) was dissolved in methanol to prepare an initiator solution with a concentration of 2.8 g / L, and bubbling with nitrogen gas was performed. Replaced with nitrogen. After adjusting the polymerization tank internal temperature to 60 ° C., 170 mL of the initiator solution was injected to initiate polymerization. During the polymerization, ethylene was introduced to maintain the reactor pressure at 5.9 kgf / cm ² , the polymerization temperature at 60 ° C., and the above initiator solution was continuously added at 610 mL / hr. After 10 hours, when the polymerization rate reached 70%, the polymerization was stopped by cooling. After the reaction vessel was opened to remove ethylene, nitrogen gas was bubbled to completely remove ethylene.

  Subsequently, the unreacted vinyl acetate monomer was removed under reduced pressure to obtain a methanol solution of ethylene-modified polyvinyl acetate (modified PVAc). Saponification was performed by adding 46.5 g of a 10% methanol solution of NaOH to 200 g of a 50% methanol solution of modified PVAc prepared by adding methanol to the solution (NaOH / vinyl acetate unit = 0.10 / 1 ( Molar ratio)). The system gelled about 2 minutes after the addition of NaOH. The gelled product was pulverized with a pulverizer and allowed to stand at 60 ° C. for 1 hour to further promote saponification, and then 1000 g of methyl acetate was added to neutralize the remaining NaOH. After confirming neutralization with a phenolphthalein indicator, the mixture was filtered to give a white solid.

  1000 g of methanol was added to the white solid, and the mixture was left to wash at room temperature for 3 hours. The above washing operation was repeated three times, and then the solution was centrifuged and left standing in a dryer at 70 ° C. for 2 days to obtain ethylene-modified polyvinyl alcohol (modified PVA). The degree of saponification of the obtained modified PVA was 98.4 mol%. Further, after the modified PVA was incinerated, a sample obtained by dissolving in acid was analyzed by an atomic absorption photometer. The content of sodium was 0.03 parts by mass with respect to 100 parts by mass of the modified PVA.

  In addition, n-hexane was added to the methanol solution of the modified PVAc, and then the precipitation-dissolution operation of adding acetone was repeated three times, followed by drying under reduced pressure at 80 ° C. for 3 days to obtain purified modified PVAc. When this modified PVAc was dissolved in d6-DMSO and analyzed using a 500 MHz proton NMR (JEOL GX-500) at 80 ° C., the content of ethylene units was 10 mol%. The above modified PVAc was saponified (NaOH / vinyl acetate unit = 0.5 (molar ratio)), pulverized, and allowed to stand at 60 ° C. for 5 hours to further promote saponification. The saponified product was extracted with methanol Soxhlet for 3 days, and the extract was dried under reduced pressure at 80 ° C. for 3 days to obtain purified modified PVA. It was 330 when the average degree of polymerization of this modified PVA was measured according to JIS K6726. The purified modified PVA was analyzed by 5000 MHz proton NMR (JEOL GX-500). As a result, the amount of 1,2-glycol bonds was 1.50 mol% and the content of 3-chain hydroxyl groups was 83%. Further, a cast film having a thickness of 10 μm was prepared from a 5% aqueous solution of the purified modified PVA. The film was dried at 80 ° C. under reduced pressure for 1 day, and then the melting point was measured by the method described above.

Example 1
The modified PVA (water-soluble thermoplastic polyvinyl alcohol: sea component), isophthalic acid-modified polyethylene terephthalate (island component) having a modification degree of 6 mol%, and the sea component / island component is 25/75 (mass ratio). It was discharged from a die for melt composite spinning (number of islands: 25 islands / fiber) at 260 ° C. The ejector pressure was adjusted so that the spinning speed was 3700 m / min, and sea-island long fibers having an average fineness of 2.1 dtex were collected on the net. Next, lightly hold the sea-island type long fiber sheet on the net with a metal roll having a surface temperature of 42 ° C, peel off from the net while suppressing fuzz on the surface, and 200N between the metal roll (lattice pattern) having a surface temperature of 75 ° C and the back roll. A long fiber web having a basis weight of 31 g / m ² in which surface fibers were temporarily fused in a lattice shape by hot pressing with a linear pressure of / mm was obtained.

An oil agent and an antistatic agent were applied to the long fiber web, and eight sheets were laminated by cross-wrapping to produce a laminated web having a total basis weight of 250 g / m ² , and sprayed with a needle breakage preventing oil agent. Next, using a 6 barb needle with a distance of 3.2 mm from the tip of the needle to the first barb, needle punching was alternately performed at 3300 punch / cm ² from both sides at a needle depth of 8.3 mm. The area shrinkage rate by this needle punching treatment was 68%, and the basis weight of the entangled web after needle punching was 320 g / m ² .

The entangled web was wound and immersed in hot water at 70 ° C. for 14 seconds at a line speed of 10 m / min to cause area shrinkage. Next, dip nip treatment was repeatedly performed in hot water at 95 ° C. to dissolve and remove the modified PVA, and entanglement in which fiber bundles having an average fineness of 2.5 decitex containing 25 polyester extra long fibers were entangled three-dimensionally. A non-woven fabric was created. The area shrinkage measured after drying was 52%, the basis weight was 480 g / m ² , the apparent density was 0.52 g / cm ³ , and the peel strength when wet was 4.2 kg / 25 mm.

  After adjusting the thickness to 0.82 mm by buffing the entangled nonwoven fabric, a soft segment is a polyurethane comprising a 70:30 mixture of polyhexylene carbonate diol and polymethylpentane diol, and a hard segment mainly comprising hydrogenated methylene diisocyanate ( A 6% aqueous emulsion having a melting point of 180 to 190 ° C., a peak temperature of loss modulus of elasticity of −15 ° C., and a hot water swelling ratio of 130% at 35 ° C. is 1.2%. And dried, and the polyurethane was adhered in fine particles onto the polyester extra long fiber.

Next, the polyurethane fine particles adhering onto the polyester extra fine fibers were dyed brown under normal pressure with a metal-containing dye (Irgalan series) under the following conditions.
Bath ratio: 1:30
Gold-containing dye usage: 5% owf
Dyeing temperature: 95 ° C
Dyeing time: 45 minutes Dyeing bath pH: 6.8
The resulting dyed polyester fiber structure had good color development and the levelness evaluation was 2.6 points. Further, when the obtained structure was observed with an electron microscope, polyurethane particles having an average particle size of 5 μm or less were attached to the surface of the ultrafine fiber bundle.

  After the dyed polyester fiber structure was press-molded at 170 ° C. and 10 kPa, the leveling property was evaluated again. The rating was 2.5, and it was confirmed that the dyed fiber structure of the present invention has high sublimation fastness.

Comparative Example 1
A sea-island composite fiber having a mass ratio of polyethylene terephthalate (PET) resin as an island component and low-density polyethylene (PE) as a sea component to 40/60 and 16 islands was melt-spun. The obtained fiber was drawn, crimped, and cut to obtain a staple having a fineness of 4 dtex and a cut length of 51 mm. After passing the obtained staple through a card, a web was produced by a cross-wrapper method. Then, a predetermined number of the obtained webs were stacked. Next, an entangled web having a weight of 663 g / m ² made of sea-island fibers was obtained by needle punching the laminated web using a felt needle.

Next, the obtained entangled web was shrunk in hot water, dried, and then hot-pressed to obtain a smooth surface, a thickness of 1.98 mm, a basis weight of 950 g / m ² , and a specific gravity of 0.480. A composite nonwoven fabric was obtained. The smoothed entangled nonwoven fabric was impregnated with a dimethylformamide (DMF) solution of polyether polyurethane (solid content 13%) so that the solid content was 20% by mass of the entangled nonwoven fabric after ultrafine fiber formation. The polyether-based polyurethane was wet-coagulated and then washed with water. Next, the sea component polyethylene was removed with hot toluene at 85 ° C. to obtain a composite of a PET ultrafine fiber entangled body and a porous polyurethane elastomer. The obtained composite contains an entangled nonwoven fabric made of a fiber bundle of PET single fibers having an average single fiber diameter of about 0.2 dtex, a thickness of 1.55 mm, a specific gravity of 0.449 g / m ³ , and a polyurethane content of 20% by mass. The basis weight was 696 g / m ² .

  Next, the composite was divided into two parts by slicing, and both surfaces of one piece were buffed using a No. 400 sandpaper to adjust the thickness to 0.75 mm and brushed. As a result, a suede-like artificial leather in which ultrafine fibers existing in the surface layer portion were raised was obtained. Next, using a disperse dye (Kiwaron Black AS-6: 22% owf, Yellow BRF: 1.0% owf, Blue 2BFL: 1.2% owf), bath ratio 1:30, dye concentration 10% owf, dyeing temperature It dye | stained on 130 degreeC and the conditions for 60 minutes of dyeing | staining conditions, and also performed reduction | restoration washing | cleaning. The resulting suede-like artificial leather had good coloration and the leveling evaluation was 2.6 points.

  This suede-like artificial leather was press-molded under the conditions of 170 ° C. and 10 kPa, and then the leveling property was evaluated again. The rating was 1.2 points, confirming that the sublimation fastness was low.

  The obtained artificial leather has a uniform color tone as well as excellent appearance, texture and mechanical properties. It is possible to use non-yellowing type resin as acid dyeable resin, and there is no concern of gas yellowing or fading, and it can be applied to applications that require high durability such as interiors. is there. In addition, because it has high sublimation fastness, it can be processed into various shapes by high-temperature molding without changing the uniform color tone, shoes, cases for various applications, mobile phone holders, home appliance exteriors, molded bags, vehicle interior materials (Control panel), suitable for materials such as game balls. Further, it can be suitably used for competition shoes (soccer, running, tennis, baskets, etc.) that are mainly molded by molding, interiors and vehicle interior materials (seats, door linings, etc.) that are likely to be discolored due to long-term use.

Claims (9)

Acid fiber non-dyeable resin fibers are included, and the acid dye non-dye resin fiber surface has 0.01 to 20% by mass of acid dye-dyeable resin with respect to the fiber of the acid dye non-dye resin. Are attached in the form of fine particles, and the acid dye-dyeable resin is dyed with an acid dye ,
A dyed fiber structure in which the acid dye-dyeable resin is a water-emulsifiable polyurethane elastomer and / or a water-emulsifiable acrylic elastomer .   The dyed fiber structure according to claim 1, wherein the acid dye non-dyeable resin is at least one resin selected from the group consisting of a polyester resin, an acrylic resin, and an olefin resin.   The fiber is an ultrafine fiber forming a fiber bundle obtained from an ultrafine fiber-forming fiber, the single fiber fineness of the ultrafine fiber is 0.001 to 2 dtex, and the fineness of the fiber bundle is 0.5 to 10 dtex The dyed fiber structure according to claim 1 or 2. The dyed fiber structure according to any one of claims 1 to 3, wherein the acid dye-dyeable resin is provided by an aqueous emulsion.   The amount of exhausted acid dyeable resin is 30 mg / g or more when dyeing under conditions of 10% owf of acid dye, bath ratio 1:45, dyeing temperature: 95 ° C., dyeing time: 60 minutes Item 5. The dyed fiber structure according to any one of Items 1 to 4. (1) a step of producing a fiber web from non-acidic dyeable resin fibers;
(2) A step of applying an entanglement treatment to the fiber web to produce an entangled nonwoven fabric;
(3) A step of imparting 0.01 to 20% by mass of an acid dye-dyeable resin in a fine particle form to the entangled nonwoven fabric, and (4) the acid dye-dyeable resin as an acid dye. in the step of dyeing sequentially line Utotomoni,
A method for producing a dyed fiber structure, wherein the acid dye-dyeable resin is a water-emulsifiable polyurethane elastomer and / or a water-emulsifiable acrylic elastomer .   The method according to claim 6, wherein the non-acidic dye-dyeable resin is at least one resin selected from the group consisting of a polyester resin, an acrylic resin, and an olefin resin. The fibrous web is made of ultrafine fiber-forming fibers;
In the step (2), the fiber web is subjected to an entanglement treatment, and then the ultrafine fiber-forming fiber is converted into a fiber bundle of ultrafine fibers to produce an entangled nonwoven fabric,
The method for producing a dyed fiber structure according to claim 6 or 7, wherein the single fiber fineness of the ultrafine fiber is 0.001 to 2 dtex, and the fineness of the fiber bundle is 0.5 to 10 dtex.   The production method according to claim 6, wherein the acid dye-dyeable resin is applied using an aqueous emulsion.