JP2008208479A - Leathery sheet and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a leathery sheet excellent in appearance, touch feeling and physical properties, and to provide the leathery sheet, further, to provide a method for producing such a leathery sheet attaining a high light resistance and abrasion resistance without substantially including a polymeric elastomer such as polyurethane and excellent in recyclability, yellowing resistance, etc., and to provide the leathery sheet. <P>SOLUTION: The method for producing the leathery sheet includes the following process: An extrafine fiber nonwoven fabric being 150-400 g/m<SP>2</SP>in basis weight and 0.20-0.35 g/cm<SP>3</SP>in density is subjected to high-speed fluid treatment at a jetting force of 0.35-1.60 N per hole from a nozzle with holes disposed at 0.15-1.50 mm intervals to effect the density of the nonwoven fabric to 0.35-0.50 g/cm<SP>3</SP>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is mainly made of a fiber material, and is excellent in appearance, texture, physical properties, and in particular, leather-like that can be suitably used for automobile interior materials that require high light resistance and wear resistance, and contract furniture for hotels, theaters, etc. The present invention relates to a sheet manufacturing method and a leather-like sheet.

  Leather-like sheets made of ultrafine fibers and polymer elastic bodies have a touch similar to that of natural leather and have excellent features not found in natural leather, such as easy care, so they are widely used in various applications. Has been.

  Generally, after a fiber sheet such as a nonwoven fabric or web is impregnated with a polymer elastic body solution such as polyurethane, the fiber sheet is immersed in water or an organic solvent aqueous solution to wet-solidify the polymer elastic body. Is adopted.

  However, in order to obtain strength, dimensional stability, etc. that can withstand practical use, since a large amount of polymer elastic body is used, the raw material cost of the polymer elastic body and the manufacturing cost of impregnating, solidifying, and drying the polymer elastic body are reduced. The leather-like sheet is getting larger and expensive.

  Further, when the amount of the polymer elastic body increases, it tends to have a rubber-like texture, and it becomes difficult to obtain a feeling of fulfillment similar to natural leather. Further, a water-miscible organic solvent such as N, N'-dimethylformamide is generally used as a solvent for impregnating the polymer elastic body, which is not preferable from the viewpoint of the working environment.

  In recent years, recyclability has been emphasized for the purpose of protecting the environment and resources. For example, polyester recovery and recovery methods (for example, see Patent Document 1) and polyurethane decomposition methods (for example, see Patent Document 2) have been studied. Has been. However, all of these methods are mainly applied to single-component materials, and composite materials in which fibers such as leather-like sheets and polymer elastic bodies such as polyurethane are separated and integrated are applied because the decomposition methods are different. Is difficult. Therefore, although it is necessary to isolate | separate into each component, cost is large and it is difficult to isolate | separate completely.

  In addition, since polyurethane and the like are easily yellowed by NOx gas or the like, it is difficult to obtain a leather-like sheet having a white color or a color close thereto.

  In order to solve these problems, a leather-like sheet has been proposed in which a polymer elastic body such as polyurethane is reduced or substantially free.

  For example, a method for producing a leather-like sheet comprising ultrafine fibers that form an appearance and fibers that fuse as a binder by swelling with heat or a solvent (see, for example, Patent Document 3). Has been proposed (see, for example, Patent Document 4). However, with this method, it is difficult to control the frequency and degree of fusion, and it is difficult to obtain a uniform fusion state even in the thickness direction of the substrate because it is fused by pressure like a press, and sufficient physical properties. Could not be obtained or became paper-like.

  On the other hand, various methods for improving entanglement have been proposed by performing high-speed fluid treatment after needle punching (see, for example, Patent Document 5). This method is useful as a means for increasing the confounding efficiency of high-speed fluid processing. However, as a result of the study by the present inventors, it has been found that it is difficult to improve the physical properties of the nonwoven fabric to such an extent that the adhesion amount of polyurethane can be reduced even if needle punching and high-speed fluid treatment are combined.

  Furthermore, a method has been proposed in which a structure in which a fabric having a high air permeability is inserted between a plurality of papermaking web layers using ultrafine fibers is integrated by hydroentanglement (see, for example, Patent Document 6). According to this method, there is no problem of tearing at the time of dyeing because the woven fabrics are laminated. However, if the polymer elastic body is not applied, the product surface has insufficient abrasion resistance as a leather-like sheet.

  In response to the above-mentioned problems, the present inventors succeeded in increasing the frequency and degree of entanglement between ultrafine fibers by a process including high-speed fluid treatment, and obtained a leather-like sheet that does not substantially contain a polymer elastic body. It has been found that this can be achieved (see, for example, Patent Document 7). According to this means, even if there is no polymer elastic body such as polyurethane, it does not have a paper-like texture, and physical properties such as wear, tension, tearing, and light resistance that can withstand the use of clothing, furniture and the like can be obtained.

However, in some applications, especially automobile interior materials and various contract furniture, high light resistance and wear resistance are required, so a leather-like sheet is formed with relatively thick polyester ultrafine fibers dyed with disperse dyes with excellent light resistance. It is preferable to do. However, since the degree of entanglement between ultrafine fibers by high-speed fluid treatment decreases as the fiber diameter increases, there is no leather-like sheet having sufficient performance for these applications.
WO01 / 30729 publication JP 2001-348457 A Japanese Patent Publication No. 7-62301 JP 61-201086 A Japanese Patent Publication No. 1-18178 Japanese Patent Laid-Open No. 7-109654 JP-A-2005-054445

  The present invention provides a method for producing a leather-like sheet excellent in appearance, texture and physical properties, and a leather-like sheet. Furthermore, the present invention provides a method for producing a leather-like sheet and a leather-like sheet that achieve high light resistance and wear resistance substantially free of a polymer elastic body such as polyurethane, and are excellent in recyclability, yellowing resistance, and the like. Is.

In order to solve the above-described problems, the present invention has the following configuration. That is,
(1) An ultrafine fiber nonwoven fabric having a basis weight of 150 to 400 g / m ² and a density of 0.20 to 0.35 g / cm ³ is 0 per hole from a nozzle arranged with a hole interval of 0.15 to 1.50 mm. A method for producing a leather-like sheet, wherein the density is 0.35 to 0.50 g / cm ³ by high-speed fluid treatment with a jet force of 35 to 1.60 N.

  (2) Using an ultrafine fiber nonwoven fabric obtained by producing a composite fiber nonwoven fabric by a needle punch method using an ultrafine fiber generating composite fiber having a single fiber fineness of 1 to 10 dtex, and then performing an ultrafine fiber expression treatment The method for producing a leather-like sheet according to (1).

  (3) The production of the leather-like sheet according to (1) or (2), wherein the fine fiber has a single fiber fineness of 0.05 to 0.50 dtex and a fiber length of 10 to 100 mm. Method.

  (4) In any one of the above (1) to (3), the fluid whose jet force is pressurized to 20 to 60 MPa is discharged from a nozzle having a hole diameter of 0.08 to 0.25 mm. The manufacturing method of the leather-like sheet | seat of description.

  (5) The method for producing a leather-like sheet according to any one of (1) to (4), wherein the ultrafine fiber nonwoven fabric and the woven / knitted fabric are laminated and integrated by high-speed fluid treatment.

  (6) A leather-like sheet obtained by the method for producing a leather-like sheet according to any one of (1) to (5).

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the leather-like sheet | seat excellent in an external appearance, a texture, and a physical property can be provided. Furthermore, it is possible to provide a method for producing a leather-like sheet and a leather-like sheet that achieve high light resistance and wear resistance substantially without containing a polymer elastic body such as polyurethane, and are excellent in recyclability, yellowing resistance, and the like. .

  The leather-like sheet obtained in the present invention does not substantially contain a polymer elastic body such as polyurethane, and is substantially made of a fiber material of an inelastic polymer. The term “substantially composed of a non-elastic polymer fiber material” as used herein means that the content of the binder composed of a polymer elastic body such as polyurethane is less than 5% by weight, preferably the binder Less than 3% by weight on the fiber, more preferably less than 1% by weight on the fiber, most preferably no binder.

  The fiber of the non-elastic polymer here means a fiber excellent in rubber-like elasticity such as a polyether-based fiber or a polyurethane-based fiber such as so-called spandex. The leather-like sheet of the present invention is most preferably one that does not contain any polymer elastic body such as polyether-based fibers or polyurethane fibers such as spandex. However, it does not deviate from the effects of the present invention. It does not matter if the body is included. In addition, functional agents such as dyes, softeners, texture modifiers, pilling inhibitors, antibacterial agents, deodorants, water repellents, light proofing agents, and antifungal agents may be included.

The present invention relates to an ultrafine fiber nonwoven fabric having a basis weight of 150 to 400 g / m ² and a density of 0.20 to 0.35 g / cm ³ from a nozzle arranged with a hole interval of 0.15 to 1.50 mm per hole. It is a method for producing a leather-like sheet, characterized in that the density is 0.35 to 0.50 g / cm ³ by high-speed fluid treatment with a jet force of 0.35 to 1.60 N.

  In the present invention, by performing a specific high-speed fluid treatment in a high-weight and low-density state, fiber fixation can be achieved at a high level with respect to a relatively thick ultrafine fiber nonwoven fabric, which has been difficult in the past, and thereby high light resistance. It has been found that sex can be obtained.

It is important that the ultrafine fiber nonwoven fabric in the present invention has a basis weight of 150 to 400 g / m ² and a density of 0.20 to 0.35 g / cm ³ , and the others are not particularly limited, and melt spinning, solution spinning Long fibers, short fibers, dry nonwoven fabrics, wet nonwoven fabrics, and laminates thereof can be used.

The lower limit of the basis weight is preferably 170 g / m ² or more, and more preferably 190 g / m ² or more. The upper limit is preferably 350 g / m ² or less, and more preferably 300 g / m ² or less. The basis weight of less than 150 g / m ^2, high physical properties are intended in the present invention, especially not obtained the abrasion resistance, the quality of high level for passage of the fluid in the high-speed fluid treatment exceeds 400 g / m ² is reduced It becomes difficult to get. Such a weight per unit area is extremely high as compared with a nonwoven fabric of 100 g / m ² or less that is generally used as a nonwoven fabric subjected to high-speed fluid treatment. In this invention, it discovered that a high physical property was acquired by performing the below-mentioned high-speed fluid process to such a high fabric weight ultrafine fiber nonwoven fabric. The reason why high physical properties can be obtained under such conditions is not clear, but for example, the frequency of fiber entanglement is increased, and because there are many fibers that come in contact with the fibers by high-speed fluid treatment from the surface layer, the pulling resistance increases. This is probably because of this.

The lower limit of the density is preferably 0.22 g / cm ³ or more, and the upper limit is preferably 0.33 g / cm ³ or less. If the density is less than 0.20 g / cm ³ , the form stability at the time of conveyance tends to be insufficient, and if it exceeds 0.35 g / cm ³ , the entanglement of fibers in the high-speed fluid treatment is difficult to proceed.

  In the present invention, a woven or knitted fabric can be laminated and integrated with the ultrafine fiber nonwoven fabric. In this case, the basis weight and density of the ultrafine fiber nonwoven fabric excluding the woven or knitted fabric may be in the above-mentioned range.

  The basis weight referred to in the present invention is a basis weight measured according to JIS L1096 8.4.2 (1999), and a value obtained by dividing the basis weight by the thickness is defined as density. The thickness was measured using a dial thickness gauge (manufactured by Ozaki Mfg. Co., Ltd., trade name “Peacock H”), 10 samples were measured, and the average value was used.

  The ultrafine fiber nonwoven fabric is subjected to high-speed fluid treatment to form a sheet. The high-speed fluid treatment for the ultrafine fiber nonwoven fabric is carried out with a jet force of 0.35 to 1.60 N per hole from a nozzle arranged with a hole interval of 0.15 to 1.50 mm. The fluid used is preferably water from the viewpoint of the working environment. Moreover, it is preferable to treat with a columnar flow because the loss of energy transmission is small. The distance between the ultrafine fiber nonwoven fabric and the hole is preferably close because energy loss can be suppressed, but if it is extremely close, the rebounding flow tends to disturb the columnar flow, so the diameter, length, shape, water pressure of the discharge hole Although the length of the columnar flow (distance until the water discharged from the holes becomes sprayed) varies depending on the etc., it is usually preferable to set it in the range of 1 to 10 cm.

The high-speed fluid treatment in the present invention is performed on the ultrafine fiber nonwoven fabric having the above-described density with a jet force of 0.35 to 1.60 N per hole. In general, in high-speed fluid processing, fluid is ejected from a plurality of nozzle heads in which holes are arranged orthogonal to a traveling sheet. The density of the sheet is increased by passing through a plurality of nozzle heads. However, it is important that the jet energy of the nozzle head is within this range in order to set the density to 0.35 g / cm ³ or more. For example, it is preferable in terms of ease of control to apply the jet force to the above-described ultrafine fiber nonwoven fabric with the first nozzle head.

  The hole interval is 0.15 to 1.50 mm, but the lower limit is preferably 0.20 mm or more, more preferably 0.25 mm or more, and further preferably 0.30 mm or more. The upper limit is preferably 1.40 mm or less, more preferably 1.30 mm or less, and even more preferably 1.20 mm or less. If the hole interval is less than 0.15 mm, the amount of water discharged in one process is large in order to obtain the required jet force, and it is easy to generate water that cannot pass through the nonwoven fabric or the support. This significantly reduces the effect of the water jet. Moreover, when the hole interval exceeds 1.50 mm, striking marks imparted to the sheet by the water flow are conspicuous, and confounding does not proceed in the untreated part.

  The jet force per hole is 0.35 to 1.60 N, but the lower limit is preferably 0.37 N or more, and more preferably 0.39 N or more. The upper limit is preferably 1.40 N or less, and more preferably 1.20 N or less. If the jet force per hole is less than 0.35 N, sufficient entanglement cannot be obtained, and the wear resistance of the product tends to be insufficient. In addition, if the jet force per hole exceeds 1.60 N, water that does not pass through the nonwoven fabric or the support is likely to be generated, and the retained water significantly reduces the effect of the water jet, and uniform processing is difficult. This is not preferable. Since such a jet force is easily obtained by setting a relatively large hole diameter, the hole diameter is preferably 0.08 to 0.25 mm, and more preferably 0.10 to 0.23 mm.

  Such a jet force is obtained by adjusting the pore diameter and the water pressure in the chamber. The jet force is calculated according to the following formula, with the hole diameter being the fluid discharge diameter.

F = 0.754 × Pg × di ²
However, F: Jet force per hole (N)
Pg: Water pressure (MPa)
di: Hole diameter (mm)
In addition, you may perform a fluid immersion process to an ultrafine fiber nonwoven fabric before performing a high-speed fluid process. Further, in order to improve the surface quality, the nozzle head and / or the ultrafine fiber nonwoven fabric can be rotated or reciprocated, or a method such as sprinkling treatment can be performed by inserting a wire mesh between the nonwoven fabric and the nozzle. .

  In general, in the case of ultrafine fibers obtained from composite fibers, the ultrafine fiber bundles in which the fibers are concentrated are mainly intertwined, but by such treatment, the intertwining by the ultrafine fiber bundles is hardly observed. Ultra fine fibers can be highly entangled with each other.

In the present invention, a thick fiber of 1 to 10 dtex is excellent in entanglement by needle punch, and a thin fiber of 0.0001 to 0.5 dtex tends to be excellent in entanglement by high-speed fluid treatment. Of ultrafine fiber generation type composite fiber is sufficiently entangled by needle punch, and then subjected to ultrafine treatment (extrafine fiber expression treatment) to obtain 0.0001 to 0.5 dtex ultrafine fiber, followed by high-speed fluid treatment Is preferred. In particular, it is important that the density of the ultrafine fiber nonwoven fabric is 0.35 to 0.50 g / cm ³ by the high-speed fluid treatment described above. As a result, high physical properties can be obtained, and even if high-speed fluid treatment is out of the above-mentioned range and a similar density is achieved, a high level of physical properties cannot be obtained. The reason for this is not clear, but it is considered that the high-speed fluid treatment of the present invention selectively contributes to confounding in preference to densification by pressing.

When the woven or knitted fabric is laminated by high-speed fluid treatment, the density of the laminated and integrated sheet may be 0.35 to 0.50 g / cm ³ regardless of the density of the woven or knitted fabric itself. As a result, high physical properties can be obtained as in the case of only the ultrafine fiber nonwoven fabric.

  Hereinafter, the production method of the present invention will be described in order.

  The so-called ultrafine fiber manufacturing method in which the single fiber fineness is in the above-mentioned range is not particularly limited. For example, a method of directly spinning ultrafine fibers, a fiber having a normal fineness and capable of generating ultrafine fibers (extrafine fibers) There is a method in which a generation type composite fiber) is spun and then an ultrafine fiber is generated by an ultrafine treatment.

  And, as a method of using the ultrafine fiber generation type composite fiber, for example, a method of removing sea components after spinning the sea-island type composite fiber, a method of spinning the split type composite fiber and then splitting and ultrafinening, etc. Can be manufactured. Among these, in the present invention, an ultrafine fiber can be obtained easily and stably, and is manufactured from a sea-island type composite fiber or a split type composite fiber (hereinafter sometimes referred to as a composite fiber). Further, when a leather-like sheet is used, it is more preferable to manufacture with a sea-island type composite fiber in that an ultrafine fiber made of the same kind of polymer that can be dyed with the same kind of dye can be easily obtained.

  As the above-mentioned sea-island type composite fiber, it is possible to use a fiber in which two or more components are combined and mixed at any stage to obtain a sea-island state. The method for obtaining this fiber is not particularly limited. For example, (1) a method in which two or more components of a polymer are blended and spun in a chip state, and (2) a mixture of two or more components in advance to form a chip. A method of spinning, (3) a method of mixing two or more polymers in a melted state in a spinning machine pack with a static kneader, etc., (4) Japanese Patent Publication No. 44-18369, Japanese Patent Laid-Open No. 54-116417. The method of manufacturing using the nozzle | cap | die of gazettes etc. is mentioned. In the present invention, any method can be used to satisfactorily produce, but the method (4) is preferably employed because the selection of the polymer is easy.

  In the method (4), the cross-sectional shape of the island fiber obtained by removing the sea-island type composite fiber and the sea component is not particularly limited, and for example, round, polygonal, Y, H, X, W, C, π type, etc. Is mentioned. Further, the number of polymer species to be used is not particularly limited, but it is preferably 2 to 3 components in consideration of spinning stability and dyeability, and particularly composed of 2 components of sea 1 component and island 1 component. It is preferable. The component ratio at this time is preferably 0.30 to 0.99, more preferably 0.40 to 0.97 in terms of weight ratio of island fibers to sea-island composite fibers, and 0.50 to 0.80. Is more preferable. If it is less than 0.30, the removal rate of sea components increases, which is not preferable in terms of cost. On the other hand, if it exceeds 0.99, the island components are likely to merge with each other, which is not preferable in terms of spinning stability.

  Further, the polymer to be used is not particularly limited, and for example, polyester, polyamide, polypropylene, polyethylene, etc. can be used as appropriate as the island component depending on the intended use. In particular, the dyeability, strength, durability, fastness, etc. In terms, polyester is preferable.

  The polyester that can be used in the present invention is a polymer that is synthesized from a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, and is particularly limited as long as it can be used as a composite fiber. Is not to be done. Specifically, for example, polyethylene terephthalate, polytrimethylene terephthalate, polytetramethylene terephthalate, polycyclohexylene dimethylene terephthalate, polyethylene-2,6-naphthalenedicarboxylate, polyethylene-1,2-bis (2- Chlorophenoxy) ethane-4,4′-dicarboxylate and the like. In the present invention, polyethylene terephthalate, which is most commonly used, or a polyester copolymer mainly containing ethylene terephthalate units is preferably used.

  The polymer used as the sea component of the sea-island composite fiber is not particularly limited as long as it has chemical properties that are higher in solubility and degradability than the polymer constituting the island component. Depending on the selection of the polymer constituting the island component, for example, polyolefins such as polyethylene and polystyrene, 5-sodium sulfoisophthalic acid, polyethylene glycol, sodium dodecylbenzenesulfonate, bisphenol A compound, isophthalic acid, adipic acid, dodecadioic acid, Polyester etc. which copolymerized cyclohexyl carboxylic acid etc. can be used. Polystyrene is preferable from the viewpoint of spinning stability, but a copolymer polyester having a sulfone group is preferable because it can be easily removed without using an organic solvent. The copolymerization ratio is preferably 5 mol% or more from the viewpoint of processing speed and stability, and 20 mol% or less from the viewpoint of ease of polymerization, spinning and stretching. A preferred combination in the present invention is a copolyester having polyester as the island component and polystyrene or sulfone group as the sea component.

  To these polymers, inorganic particles such as titanium oxide particles may be added to the polymer in order to improve the concealing property. In addition, lubricants, pigments, heat stabilizers, ultraviolet absorbers, conductive agents, heat storages, etc. An agent, an antibacterial agent and the like can be added according to various purposes.

  Moreover, it does not specifically limit about the method of obtaining a sea-island type composite fiber, For example, after taking an undrawn yarn using the nozzle | cap | die shown to the method of said (4), it is 1-by wet heat or dry heat, or both. It can be obtained by three-stage stretching.

  In addition, when using split type composite fiber, it can mainly carry out according to the manufacturing method of the above-mentioned sea-island type composite fiber, combining two or more components within the die.

  As a method for obtaining an ultrafine fiber nonwoven fabric, a nonwoven fabric (composite fiber nonwoven fabric) is produced using the above-mentioned ultrafine fiber generation type fiber (composite fiber), and then ultrafinely formed into an ultrafine fiber nonwoven fabric. There is a method of using a fiber nonwoven fabric. Since the former is preferably employed in the present invention, this method will be described below as an example.

  As a method for producing the nonwoven fabric, the web may be produced by either a dry method such as a spunbond method or a card method, or a wet method such as a papermaking method. Since the longer length is advantageous, the dry method is preferred. The fiber length is preferably 10 to 100 mm in consideration of productivity and the texture of the product obtained. The lower limit is more preferably 20 mm or more, and further preferably 30 mm or more. The upper limit is more preferably 90 mm or less, and still more preferably 80 mm or less. A fiber length exceeding 100 mm may be included as long as the effects of the present invention are not impaired. Further, the lower limit is not particularly limited and can be appropriately set depending on the method for producing the nonwoven fabric. However, if it is less than 10 mm, the dropout tends to increase, and the properties such as strength and wear resistance tend to decrease. This is because productivity and productivity are likely to decrease.

  As a method for obtaining such a fiber having a long fiber length, a method in which an undrawn yarn obtained directly or as a composite fiber is drawn and then shortened with a rotary cutter or a guillotine cutter.

  The ultrafine fiber of the present invention has a single fiber fineness in the range of 0.0001 to 0.5 dtex, but is preferably 0.05 dtex or more, and more preferably 0.08 dtex or more in terms of light resistance. In general, when the fiber becomes thicker, confounding in the high-speed fluid treatment is difficult to proceed and the physical properties tend to be low. However, according to the production method of the present invention, high physical properties can be obtained.

  The ultrafine fiber nonwoven fabric in the present invention is preferably a short fiber nonwoven fabric in order to obtain excellent quality and texture. In particular, the aspect ratio of the ultrafine fiber is preferably 5,000 to 900,000 in consideration of productivity and the texture of the obtained product. The aspect ratio here is a value obtained by dividing the fiber length by the fiber diameter, preferably 10,000 to 500,000, and more preferably 20,000 to 50,000. If the aspect ratio is less than 5,000, the dropout tends to increase, and the properties such as strength and wear resistance tend to decrease. If the aspect ratio exceeds 900,000, the number of fibers decreases, and the uniformity tends to be impaired. Further, in the above-described high-speed fluid treatment, since the entanglement and catch per number of fibers are reduced when the aspect ratio is less than 5,000, the form is easily destroyed by high-pressure treatment. When the aspect ratio exceeds 900,000, the water pressure necessary for entanglement This is economically disadvantageous because the amount of water increases. The aspect ratio referred to in the present invention can be obtained by directly measuring the length and diameter of the ultrafine fiber extracted from the ultrafine fiber nonwoven fabric. Note that the diameter of the circumscribed circle is used when the cross section is not a circle.

From the above, the composite fiber nonwoven fabric is preferably a composite short fiber nonwoven fabric. The composite short fiber nonwoven fabric is brought to a density in the range of 0.35 to 0.50 g / cm ³ by needle punching. The lower limit of the density is preferably 0.120 g / cm ³ or more, and more preferably 0.150 g / cm ³ or more. The upper limit is preferably 0.300 g / cm ³ or less, and more preferably 0.250 g / cm ³ . If it is less than 0.120 g / cm ³ , the entanglement will be insufficient, and it will be difficult to obtain the desired physical properties. If it exceeds 0.300 g / cm ³ , the needle needle will be broken or the needle hole will remain. This is not preferable because of the above problem.

  When performing needle punching, the lower limit of the single fiber fineness of the composite fiber is preferably 1 dtex or more, and more preferably 2 dtex or more. The upper limit is preferably 10 dtex or less, more preferably 8 dtex or less, and even more preferably 6 dtex or less. When the single fiber fineness is less than 1 dtex or exceeds 10 dtex, the entanglement by the needle punch becomes insufficient, and it becomes difficult to obtain an ultrafine fiber nonwoven fabric with good physical properties.

In the needle punch according to the present invention, it is preferable that the fibers are sufficiently entangled rather than merely serving as temporary fixing for obtaining process passability. When the driving density is too high, the fibers are likely to be cut and the physical properties are easily lowered. Therefore, the lower limit of the driving density is preferably 100 / cm ² or more, more preferably 500 / cm ² or more, and 1000 / cm ^2. The above is more preferable. The upper limit of the driving density is preferably 5000 / cm ² or less, and more preferably 4000 / cm ² or less.

  The composite short fiber nonwoven fabric thus obtained is preferably shrunk by dry heat and / or wet heat, and further densified.

  Next, the composite short fiber nonwoven fabric is subjected to an ultrafine treatment to make it ultrafine. It is possible to combine high-speed fluid processing with ultrafine processing, but it is preferable to perform high-speed fluid processing at least after the microminiaturization processing has been completed, in order to promote the entanglement between ultrafine fibers. More preferably, the high speed fluid treatment is performed after the treatment.

  The ultrafine treatment method is not particularly limited, and examples thereof include a mechanical method and a chemical method. The mechanical method is a method of miniaturization by applying a physical stimulus. For example, in addition to the method of giving an impact such as the needle punch method and the high-speed fluid processing method using water, between the rollers. Examples include a method of applying pressure and a method of performing ultrasonic treatment. The chemical method includes, for example, a method in which at least one component constituting the composite fiber is subjected to changes such as swelling, decomposition, and dissolution by a drug. In particular, a method of preparing a composite short fiber nonwoven fabric with sea-island type composite fiber using an alkali-degradable sea component, and then treating it with a neutral to alkaline aqueous solution to make it ultrafine is preferable in working environment without using a solvent. Therefore, this is one of the preferred embodiments of the present invention. The neutral to alkaline aqueous solution is an aqueous solution having a pH of 6 to 14, and the chemicals used are not particularly limited. For example, an aqueous solution containing organic or inorganic salts may be used as long as it exhibits a pH in the above range, and alkali metal salts such as sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium carbonate, sodium bicarbonate, calcium hydroxide, water Examples include alkaline earth metal salts such as magnesium oxide. Further, if necessary, amines such as triethanolamine, diethanolamine, monoethanolamine, a weight loss accelerator, a carrier, and the like can be used in combination. Of these, sodium hydroxide is preferable in terms of price and ease of handling. Furthermore, it is preferable that the composite short fiber nonwoven fabric is subjected to the neutral to alkaline aqueous solution treatment described above, and then neutralized and washed as necessary to remove residual chemicals and decomposition products, and then dried.

  In addition, as a method of simultaneously performing these ultrafine processing and high-speed fluid processing, for example, a method of performing removal and entanglement by high-speed fluid processing with water using a composite fiber made of water-soluble sea components, different alkali decomposition rates Examples include a method of using a composite fiber of two or more components, decomposing an easily soluble component through an alkali treatment solution, and then performing final removal and entanglement treatment by high-speed fluid treatment with water.

  Here, the high-speed fluid treatment is as already described in detail.

  In the present invention, it is preferable to add a form stabilizer for the purpose of improving the form stability of the ultrafine fiber nonwoven fabric during high-speed fluid treatment. In particular, it is preferable to apply a water-soluble form stabilizer to the nonwoven fabric before and after the ultrafine treatment, and to remove the nonwoven fabric when the nonwoven fabric is stabilized by the high-speed fluid treatment with water. As such a water-soluble form stabilizer, organic substances such as polyvinyl alcohol or derivatives thereof, water-soluble starch, carboxymethyl cellulose, partially saponified acrylate ester, polyacrylamide, and cellulose acetate are preferable. These water-soluble form stabilizers are applied to webs and non-woven fabrics as aqueous solutions or emulsions, but for the application treatment of aqueous solutions or emulsions of form stabilizers, those subjected to impregnation method, spray method, coating method, etc. are dried by heat. It can be processed by a conventional method such as a coagulation method, a wet coagulation method with water or the like, and an appropriate steam treatment. If the applied amount is too small, it will be difficult to maintain the form and function.If the applied amount is too large, the effect of high-speed fluid treatment with water will be hindered and the entanglement of ultrafine fibers will be difficult to proceed. 3 to 60% by weight is preferable, and 5 to 50% by weight is more preferable.

  The leather-like sheet obtained in the present invention may contain woven or knitted fabrics as long as it contains an ultrafine fiber nonwoven fabric.

  Lamination of the woven or knitted fabric and the ultrafine fiber nonwoven fabric (or sheet) can be achieved by stacking them before the needle punching step or the high-speed fluid processing step and entanglement and integration by each processing. At this time, entanglement and integration may be performed in any of the needle punching step and the high-speed fluid treatment step, but the fibers constituting the woven or knitted fabric are difficult to be cut. Therefore, lamination by entanglement integration in the high-speed fluid treatment is preferable. At this time, the ultrafine fiber nonwoven fabric can be arranged on one side or both sides of the woven or knitted fabric.

  When applying a small amount of a binder made of a polymer elastic body such as polyurethane, before ultrafine treatment, after ultrafine treatment, before lamination with woven or knitted fabric, after lamination with woven or knitted fabric, before dyeing, after dyeing, etc. , May be performed at any time. As a method for imparting the binder, a usual method can be employed.

  Furthermore, in order to obtain a suede-like or nubuck-like leather-like sheet, it is preferable to perform a raising process with a sandpaper or a brush. Such raising treatment can be performed before or after dyeing, or before and after dyeing.

  And it is preferable that such a leather-like sheet is dyed. The dyeing method is not particularly limited, and the dyeing machine to be used may be any of a liquid dyeing machine, a thermosol dyeing machine, a high-pressure jigger dyeing machine, and the like. It is preferable to dye using a dyeing machine.

  As the kind of dye used for dyeing, a dye having excellent color developability and fastness, which is appropriately selected from disperse dyes, vat dyes, acid dyes, metal-containing dyes, reactive dyes and the like depending on the polymer type of the leather-like sheet is preferable. For example, when dyeing the leather-like sheet of the present invention made of a polyester fiber material, a disperse dye having good light resistance such as anthraquinone and quinophthalone is preferably used. In addition, pH adjusting agents such as acetic acid and sodium acetate, leveling agents, and dispersing agents can be appropriately added to the dyeing bath. After dyeing, washing can be performed to remove dyes and auxiliaries adhering to the leather-like sheet surface and fiber entanglement points, and to improve the fastness of the product. As a cleaning method, a commonly used method can be used. For example, when polyester is used as a fiber and dyed with a disperse dye, pH adjustment of a reducing agent such as hydrosulfite, a surfactant, sodium hydroxide, etc. It is preferable to carry out at a temperature of 60 to 100 ° C. for about 20 to 30 minutes using an agent or the like.

  In addition, the leather-like sheet may be either a silvered tone or a napped tone, but if it is made only of a fiber material, it is possible to obtain a better surface quality especially with a raised nap tone, so at least one of them The surface is preferably raised. In the case of obtaining a silver-tone surface, a method of forming an ultra-high density fiber layer on the surface is preferable, unlike the conventional method of forming a resin layer such as polyurethane. The leather-like sheet obtained by the present invention is substantially made of a fiber material, but has a surface quality similar to that of general natural leather or artificial leather, unlike a simple nonwoven fabric.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the physical-property value in an Example was measured by the method described below.

(1) Weight per unit area, density The basis weight was measured by the method of JIS L 1096 8.4.2 (1999). Further, the thickness was measured with a dial thickness gauge (manufactured by Ozaki Mfg. Co., Ltd., trade name “Peacock H”), and the density was determined by calculation from the basis weight value.

(2) Light resistance According to JIS L 0843 (1998) xenon arc lamp test (method B-6, water-cooled, inner filter: quartz, outer filter: borosilicate glass, radiation exposure: 77.8 MJ / m ² ) It was measured.

(3) Abrasion resistance JIS L 1096 (1999) 8.17.5 E method (Martindale method) Wear in 3000 times and 20000 times in the wear resistance test measured according to furniture load (12 kPa) Then, the weight loss of the test cloth was evaluated, and the grade was judged from the appearance according to the judgment standard table of JIS L 1076 (1992) Table 2. The weight loss was a value when it was worn out 20000 times, and the appearance was judged as a low grade out of 3000 times and 20000 times.

(4) Appearance The appearance of the product surface was visually evaluated in three stages of ○ to ×. In addition, (circle)-* was determined by the following content.
○: Color, napped, smoothness is uniform and no hole is present Δ: Any of color, napped, smoothness is not uniform, and no hole is present ×: Any of color, napped, smoothness is not uniform, There is a hole.

Production Example 1 (Production of Fabric 1)
A low-viscosity component composed of polyethylene terephthalate having an intrinsic viscosity of 0.40 and a high-viscosity component composed of polyethylene terephthalate having an intrinsic viscosity of 0.75 are bonded side by side at a weight composite ratio of 50:50, and spun and stretched. A composite multifilament fiber yarn of decitex 12 filaments was obtained. This was additionally twisted at 1500 T / m (twisting coefficient 11225) and steam set at 65 ° C. This yarn was used as warp yarn and weft yarn, and the woven structure was made into a plain weave and woven at a density of 94 × 64 / 2.54 cm. This woven fabric was scoured at 98 ° C. and then subjected to a relaxation treatment at 110 ° C. using a liquid dyeing machine to obtain a woven fabric 1 having a weave density of 122 × 87 pieces / 2.54 cm and a basis weight of 64 g / m ² .

Production Example 2 (Production of woven fabric 2)
A polyethylene terephthalate component having an intrinsic viscosity of 0.66 was spun and drawn to obtain a composite fiber of 56 dtex 48 filaments. This was twisted by S twisting at 2400 T / m (twisting coefficient 17960) and steam set at 75 ° C. Similarly, a Y-twisted 2400 T / m (twisting coefficient 17960) twisted yarn was set at 75 ° C. and steam set. S warp yarns and Z twist yarns are alternately arranged on the warp yarns, and the weave fabrics are plain weaves using S twist yarns on the weft yarns, and a woven fabric is produced with a weave density of 93 × 64 / 2.54 cm. , 60 g / m ² of woven fabric 2 was obtained.

Example 1
A web was prepared through a card and a cross wrapper using a sea-island type composite short fiber having a monofilament fineness of 4 dtex, 16 islands, and a fiber length of 51 mm, comprising 20 parts of polystyrene as a sea component and 80 parts of polyethylene terephthalate as an island component. Next, needle punching was performed with a 1 barb type needle at a density of 2500 pieces / cm ² to obtain a composite short fiber nonwoven fabric having a density of 0.210 g / cm ³ . Next, it was immersed in an aqueous solution of 12% polyvinyl alcohol having a polymerization degree of 500 and a saponification degree of 88% heated to about 95 ° C. so as to have an adhesion amount of 25% with respect to the weight of the nonwoven fabric in terms of solid content. , PVA) was impregnated for 2 minutes simultaneously with impregnation, and dried at 100 ° C. to remove moisture. The obtained sheet was treated with tricrene at about 30 ° C. until the polystyrene was completely removed to obtain an ultrafine fiber nonwoven fabric having a basis weight of 285 g / m ² , a density of 0.34 g / cm ³ , and a single fiber fineness of 0.2 dtex.

  Next, in a state where the woven fabric 1 of Production Example 1 is laminated on the back side of the above-mentioned ultrafine fiber nonwoven fabric, 5 m / After processing 3 times at 40 MPa from the table at a processing speed of 1 minute, the same processing was performed 3 times from the back (6 times in total), and entanglement was performed with the removal of PVA.

The sheet thus obtained was a dense sheet in which PVA was completely removed, the density was 0.40 g / cm ³ , and ultrafine fibers were intertwined.
After buffing the surface of the obtained sheet with a wide belt sander manufactured by Kikukawa Iron Works Co., Ltd. using a silicon carbide abrasive sandpaper with a particle size of P400 until the weight loss due to buffing of the fiber sheet is 5% by weight. , A beige dye composed of anthraquinone and quinophthalone dyes at a concentration of 1.8% owf at 120 ° C., 45 After dyeing in minutes, wash in a liquid bath of hydrosulfite 4 g / l, sodium hydroxide 1.5 g / l, and surfactant 0.2 g / l at 80 ° C. for 20 minutes, and then at 40 ° C. for 20 minutes. After washing, it was dehydrated with a mangle, and 8 g / l of Lsoft N500 Conk (manufactured by Yushi Kogyo Co., Ltd.) as a softening agent was applied by a pad method using a mangle. The wet pick-up rate of the liquid at this time was 80% by weight with respect to the sheet-like material. Thereafter, it was dried at 100 ° C. to obtain a leather-like sheet consisting only of a suede-like fiber material. The results of evaluating the physical properties of the obtained leather-like sheet are shown in Table 1.

Example 2
A web was prepared through a card and a cross wrapper using a sea-island type composite short fiber having a monofilament fineness of 4 dtex, 16 islands, and a fiber length of 51 mm, comprising 20 parts of polystyrene as a sea component and 80 parts of polyethylene terephthalate as an island component. Next, the above-described web and the fabric 2 of Production Example 2 were laminated and subjected to needle punching treatment with a density of 2500 / cm ² with a 1 barb needle to obtain a composite short fiber nonwoven fabric having a density of 0.260 g / cm ^3. It was. Next, it was immersed in an aqueous solution of 5% polyvinyl alcohol having a degree of polymerization of 500 and a saponification degree of 88% heated to about 95 ° C. so as to give an adhesion amount of 10% with respect to the weight of the nonwoven fabric in terms of solid content. , PVA) was impregnated for 2 minutes simultaneously with impregnation, and dried at 100 ° C. to remove moisture. The obtained ultrafine fiber nonwoven fabric was treated with tricrene at about 30 ° C. until the polystyrene was completely removed, and an ultrafine fiber nonwoven fabric having a basis weight of 400 g / m ² , a density of 0.28 g / cm ³ , and a single fiber fineness of 0.2 dtex was obtained. .
Next, after processing three times at 40 MPa from the front at a processing speed of 5 m / min by high-speed fluid processing using water consisting of a nozzle head having a hole diameter of 0.14 mm and an interval of 0.7 mm, 3 from the back The process was repeated (6 times in total) and entangled with the removal of PVA.

The sheet thus obtained was a dense sheet in which PVA was completely removed, the density was 0.48 g / cm ³ , and ultrafine fibers were intertwined.
The obtained sheet was processed in the same manner as in Example 1 to obtain a leather-like sheet consisting only of a suede-like fiber material. The results of evaluating the physical properties of the obtained leather-like sheet are shown in Table 1.

Example 3
A leather-like sheet consisting only of a suede-like fiber material was obtained in the same manner as in Example 1 except that the amount of raw cotton fed into the card was reduced. The results of evaluating the physical properties of the obtained leather-like sheet are shown in Table 1.

Example 4
A leather-like sheet was obtained in the same manner as in Example 1 except that treatment was performed at 35 MPa on both the front and back surfaces with a nozzle diameter of 0.12 mm and an interval of 0.6 mm, and entanglement was performed together with the removal of PVA. Table 1 shows the physical properties of the obtained leather-like sheet.

Example 5
A leather-like sheet was obtained in the same manner as in Example 1 except that treatment was performed at 25 MPa on both sides with a nozzle having a hole diameter of 0.25 mm and an interval of 1.5 mm, and entanglement was performed together with removal of PVA. Table 1 shows the physical properties of the obtained leather-like sheet.

Comparative Example 1
A leather-like sheet consisting only of a suede-like fiber material was obtained in the same manner as in Example 1 except that the amount of raw cotton fed into the card was reduced (that is, the basis weight of the ultrafine fiber nonwoven fabric before the high-speed fluid treatment was small). . The results of evaluating the physical properties of the obtained leather-like sheet are shown in Table 1.

Comparative Example 2
A leather-like sheet made only of a suede-like fiber material was obtained in the same manner as in Example 1 except that the amount of raw cotton input to the card was increased (that is, the basis weight of the ultrafine fiber nonwoven fabric before high-speed fluid treatment was large). . The results of evaluating the physical properties of the obtained leather-like sheet are shown in Table 1.

Comparative Example 3
A web was prepared through a card and a cross wrapper using a sea-island type composite short fiber having a monofilament fineness of 4 dtex, 16 islands, and a fiber length of 51 mm, comprising 20 parts of polystyrene as a sea component and 80 parts of polyethylene terephthalate as an island component. Next, needle punching was performed with a 1 barb-type needle at a driving density of 500 pieces / cm ² to obtain a composite short fiber nonwoven fabric having a density of 0.170 g / cm ³ . Next, it is immersed in an aqueous solution of 22% polyvinyl alcohol having a polymerization degree of 500 and a saponification degree of 88% heated to about 95 ° C. so as to have an adhesion amount of 46% with respect to the nonwoven fabric weight in terms of solid content. , PVA) was impregnated for 2 minutes simultaneously with impregnation, and dried at 100 ° C. to remove moisture. The obtained ultrafine fiber nonwoven fabric was treated with tricrene at about 30 ° C. until the polystyrene was completely removed to obtain an ultrafine fiber nonwoven fabric having a basis weight of 285 g / m ² , a density of 0.18 g / cm ³ , and a single fiber fineness of 0.2 dtex. .

  The ultrafine fiber nonwoven fabric was treated in the same manner as in Example 1 to obtain a leather-like sheet composed only of a suede-like fiber material. The results of evaluating the physical properties of the obtained leather-like sheet are shown in Table 1.

Comparative Example 4
A web was prepared through a card and a cross wrapper using a sea-island type composite short fiber having a monofilament fineness of 4 dtex, 16 islands, and a fiber length of 51 mm, comprising 20 parts of polystyrene as a sea component and 80 parts of polyethylene terephthalate as an island component. Next, needle punching was performed with a 1 barb type needle at a density of 2500 pieces / cm ² to obtain a composite short fiber nonwoven fabric having a density of 0.210 g / cm ³ . Next, it is immersed in an aqueous solution of 2% polyvinyl alcohol having a polymerization degree of 500 and a saponification degree of 88% heated to about 95 ° C. so as to give an adhesion amount of 4% with respect to the nonwoven fabric weight in terms of solid content. , PVA) was impregnated for 2 minutes simultaneously with impregnation, and dried at 100 ° C. to remove moisture. The obtained ultrafine fiber nonwoven fabric was treated with tricrene at about 30 ° C. until the polystyrene was completely removed, and an ultrafine fiber nonwoven fabric having a basis weight of 285 g / m ² , a density of 0.40 g / cm ³ and a single fiber fineness of 0.2 dtex was obtained. .

  The ultrafine fiber nonwoven fabric was treated in the same manner as in Example 1 to obtain a leather-like sheet composed only of a suede-like fiber material. The results of evaluating the physical properties of the obtained leather-like sheet are shown in Table 1.

Comparative Example 5
A leather-like sheet was obtained in the same manner as in Example 1 except that treatment was carried out with a jet force of 0.30 N with a nozzle having a hole diameter of 0.10 mm and a spacing of 0.6 mm, and entanglement was performed together with the removal of PVA. Table 1 shows the physical properties of the obtained leather-like sheet.

Comparative Example 6
A leather-like sheet was obtained in the same manner as in Example 1 except that treatment was performed with a jet force of 1.89 N with a nozzle having a hole diameter of 0.25 mm and an interval of 1.5 mm, and entanglement was performed together with the removal of PVA. Table 1 shows the physical properties of the obtained leather-like sheet.

Comparative Example 7
A leather-like sheet was obtained in the same manner as in Example 1 except that treatment was carried out with a nozzle having a hole diameter of 0.14 mm and intervals of 2.0 mm, and entanglement was carried out together with removal of PVA. Table 1 shows the physical properties of the obtained leather-like sheet.

  According to the present invention, it is possible to obtain sufficient physical properties and quality as a leather-like sheet even in a nonwoven fabric structure that is substantially free of a polymer elastic body and mainly made of a fiber material. The ultra-fine fiber nonwoven fabric of the present invention has excellent characteristics such as recyclability, easy care properties, yellowing resistance, etc., so it can be used for clothing, furniture, car seats, miscellaneous goods, abrasive cloth, wipers, filters, etc. Among them, it can be preferably used particularly for automobile interior materials and various contract materials by utilizing recyclability and high light resistance.

Claims (6)

An ultrafine fiber nonwoven fabric having a basis weight of 150 to 400 g / m ² and a density of 0.20 to 0.35 g / cm ³ is 0.35 per hole from a nozzle arranged with a hole interval of 0.15 to 1.50 mm. A method for producing a leather-like sheet, characterized by performing high-speed fluid treatment with a jet force of 1.60 N to make the density 0.35 to 0.50 g / cm ³ . An ultrafine fiber nonwoven fabric obtained by producing a composite fiber nonwoven fabric by a needle punch method using an ultrafine fiber generating composite fiber having a single fiber fineness of 1 to 10 dtex, and then performing an ultrafine fiber expression treatment is used. Item 2. A method for producing a leather-like sheet according to Item 1. The method for producing a leather-like sheet according to claim 1 or 2, wherein the fine fiber has a single fiber fineness of 0.05 to 0.50 dtex and a fiber length of 10 to 100 mm. The leather-like sheet according to any one of claims 1 to 3, wherein the fluid whose jet force is pressurized to 20 to 60 MPa is discharged from a nozzle having a hole diameter of 0.08 to 0.25 mm. Production method. The method for producing a leather-like sheet according to any one of claims 1 to 4, wherein the ultrafine fiber nonwoven fabric and the woven or knitted fabric are laminated and integrated by high-speed fluid treatment. A leather-like sheet obtained by the method for producing a leather-like sheet according to any one of claims 1 to 5.