JP4997890B2 - Method for producing artificial leather substrate - Google Patents

Description

  The present invention relates to a method for producing a non-woven fabric and a method for producing an artificial leather-based non-woven fabric that are simpler, more stable, and have less environmental impact than conventional methods for producing non-woven fabrics and artificial leather-based substrates.

  Various types of artificial leather obtained by adding a polymer elastic body to a nonwoven fabric have been studied. For example, polyethylene terephthalate (PET), polyester typified by polybutylene terephthalate (PBT), and polycondensation polymers typified by nylon 6 (N6) and nylon 66 (N66) have appropriate mechanical properties and heat resistance. It has been suitably used for artificial leather for clothing, interiors, vehicle interiors, industrial materials and the like.

Nonwoven fabrics made of ultrafine fibers are widely used as the base material for artificial leather, but methods for obtaining ultrafine fibers include a method of directly spinning, a method of dividing a split-type composite spun yarn, and a sea-island type composite. A method of extracting and removing sea components from the spun yarn is common.
For example, a technique relating to a polyester ultrafine fiber suitable for use in artificial leather is already known (see Patent Document 1). According to this technology, when used in artificial leather, it exhibits excellent wear resistance. However, the direct spinning of ultrafine fibers has a low production stability, and the ultrafine fibers are also very difficult to spin below a single fiber fineness of about 0.1 dtex.

  Moreover, the technique regarding the artificial leather which consists of a composite fiber which uses a polystyrene for a sea component as an ultrafine fiber generation type composite fiber is already known (refer patent document 2). According to this technology, it seems that ultrafine fibers that are the base material of artificial leather can be produced stably. For example, when polystyrene is used as a sea component, organic components such as trichlorethylene are used to extract and remove sea components. A solvent was required, and the production method had a very large environmental impact. Furthermore, a technique relating to a leather-like sheet-like material made of a composite fiber using polyethylene terephthalate capable of alkali elution as a sea component is also known as an ultrafine fiber-generating composite fiber (see Patent Document 3). However, polyethylene terephthalate which is extracted and discarded is made of so-called petroleum-based raw materials, and has no small environmental impact.

  Furthermore, artificial leather made of ultrafine fibers obtained by treating with water is also known (see Patent Document 4). According to this technique, it is possible to obtain ultrafine fibers without using the chemicals as described above, and it can be said that the production method has a small environmental impact. However, in consideration of polymer selection, spinning stability, etc., it was not a simple production method.

Furthermore, a long-fiber nonwoven fabric that expresses ultrafine fibers by alkali treatment and a method for producing artificial leather using the same are known. As an example of the technology, polylactic acid fibers are used as fibers that are hydrolyzed by alkali treatment. (See Patent Document 5). However, it is only shown that polylactic acid fiber can be used as a fiber hydrolyzed by alkali treatment, and no description is given of the type and characteristics of a polymer suitable for polyspinning with polylactic acid. Not. Since polylactic acid is easily pyrolyzed at high temperatures, when performing composite spinning, it is necessary to select a polymer to be composite-spun from those having an appropriate melting point and spinnable temperature. In particular, when spinning ultrafine fibers, it is important to select properties such as the melt viscosity of the polymer to be combined in order to control the composite state. However, there is no description about problems in making a composite fiber.
JP 2003-41432 A JP 2004-52120 A JP 2004-100051 A JP 2003-328276 A JP 2004-84076 A

  In view of the background of such prior art, the present invention provides not only excellent texture and strength, but also provides a method for producing a nonwoven fabric and a method for producing artificial leather that are simple and high in production stability and have a low environmental impact. Is.

The present invention employs the following means in order to solve such problems. That is, the method for producing an artificial leather substrate of the present invention is an aliphatic having a melt flow rate (MFR) of 20 to 300 g / 10 min measured based on ASTM D1238 (measurement temperature 240 ° C., measurement load 2.16 kg load). Before spunbond nonwoven fabric composed of split ultrafine fiber-generating composite fibers obtained by composite spinning of polyester and polyamide satisfying the following MFR is treated with an alkali solution to extract and remove the aliphatic polyester Or after that, a polymer elastic body is provided.

  According to the present invention, it is possible to produce a non-woven fabric and artificial leather that are not only simple and high in production stability but also have a low environmental impact.

  The present invention is not only excellent in the above-mentioned problems, that is, texture and strength, but also has a specific melt flow rate (MFR) by intensively studying a method for producing a nonwoven fabric that is simple and has high production stability and low environmental impact. Using an aliphatic polyester, selecting a polyamide that satisfies the specific MFR relationship by attracting to the aliphatic polyester, and combining the specific polyamide with the specific aliphatic polyester to form an ultrafine fiber generating composite As a result of manufacturing a nonwoven fabric using fibers, it was found that this problem can be solved all at once.

The ultrafine fiber generating composite fiber in the present invention can be obtained by composite spinning of polyamide and aliphatic polyester. The polyamide in the present invention is not limited at all as long as it can be fiberized with a synthetic polymer having an amide bond (—CONH—), but nylon 6, nylon 66, nylon 6-10, nylon 12, or these Copolymers and modified products can be used alone or in combination. In selecting the polyamide, it is preferable to select a polyamide having a small melting point difference from the aliphatic polyester. In addition, a crystal nucleating agent, a matting agent, a pigment, an antifungal agent, an antibacterial agent, a flame retardant, an antistatic agent, a hydrophilic agent, a lubricant and the like may be added to the polyamide as long as the effects of the present invention are not impaired.

  The aliphatic polyester in the present invention is not particularly limited as long as it can be hydrolyzed by an alkaline solution. For example, polylactic acid, polyglycolic acid, polyhydroxybutyrate, polyhydroxybutyrate valerate, or a copolymer thereof. Or modified products can be used alone or in a blend. Of these, a polylactic acid resin is most preferred because it has good spinnability and can be synthesized from starch derived from plants, and has low environmental impact.

  As such a polylactic acid-based resin, poly (D-lactic acid), poly (L-lactic acid), a copolymer of D-lactic acid and L-lactic acid, or a blend thereof (including a stereo complex) is preferable. It is. The weight average molecular weight of such a polylactic acid resin is preferably 50,000 to 300,000, more preferably 70,000 to 300,000. When the weight average molecular weight is less than 50,000, the strength of the fiber tends to be low, and when the weight average molecular weight exceeds 300,000, the spinnability of the polymer extruded from the nozzle is poor because the viscosity is high, It becomes difficult to draw at high speed, and ultimately it becomes an undrawn state, and there is a tendency that sufficient fiber strength cannot be obtained. In addition, crystal nucleating agents, matting agents, pigments, antifungal agents, antibacterial agents, flame retardants, antistatic agents, hydrophilic agents, lubricants and the like may be added to the aliphatic polyester as long as the effects of the present invention are not impaired. Good.

  Furthermore, the melt flow rate (MFR) of the aliphatic polyester of the present invention is 20 to 300 g / 10 min, and the relationship between the MFR of the polyamide and the MFR of the aliphatic polyester is (MFR of aliphatic polyester) / (polyamide). It is important that MFR) is in the range of 0.3 to 3.0.

  When the MFR of the aliphatic polyester is less than 20, the spinnability of the polymer tends to deteriorate, and when the MFR exceeds 300, the strength of the yarn tends to decrease, which is not preferable. The MFR of the more preferable aliphatic polyester is in the range of 25 to 280 g / 10 min, particularly preferably 30 to 250 g / 10 min.

  In addition, if the relationship between the MFR values of the polyamide and the aliphatic polyester ((MFR of aliphatic polyester) / (MFR of polyamide)) is in the range of 0.3 to 3.0, the polyamide and the aliphatic polyester The spinnability at the time of composite spinning tends to be good, and the resulting ultrafine fiber nonwoven fabric and artificial leather base material tend to have sufficient strength, which is preferable. A more preferable value (MFR of aliphatic polyester) / (MFR of polyamide) is 0.5 to 2.8, and more preferably 0.8 to 2.5.

  The MFR of the aliphatic polyester and polyamide of the present invention is measured based on ASTM D1238 (measurement temperature 240 ° C., measurement load 2.16 kg load), and 10 measurements are carried out for each sample. The average value is obtained by rounding off the first decimal place.

The ultrafine fiber-generating composite fiber in the present invention is composed of a polyamide component and an aliphatic polyester component, and the polyamide component and the aliphatic polyester component are selected from a split type, a sea-island type, and a mixed type. Among these, it is most preferable to use a split-type conjugate fiber because it is easy to produce and has high production stability.

It is preferable that the single fiber fineness of the polyamide fiber after elution of the aliphatic polyester component from these composite fibers by alkali processing is 1 dtex or less. When the single fiber fineness of the polyamide fiber exceeds 1 dtex, it is not preferable because the texture of the artificial leather tends to become hard, particularly when a nonwoven fabric is used as the base material of the artificial leather. The single fiber fineness of the polyamide fiber is more preferably 0.5 dtex or less, and still more preferably 0.3 dtex or less.
In addition, the single fiber fineness in this invention collects 10 small piece samples at random from a sample, takes a photograph of 500 to 3000 times with a scanning electron microscope or the like, 10 pieces from each sample, 100 fibers in total. The cross-sectional area is measured, the average value thereof is calculated, this is converted into the fiber diameter of the circular fiber, and corrected by the polymer density.

  The weight ratio of the polyamide component and the aliphatic polyester component in the composite fiber of the present invention is preferably in the range of polyamide: aliphatic polyester = 20: 80 to 80:20. When the weight ratio of the polyamide component is less than 20% by weight, the ratio of the eluted component is large, and thus the productivity is low, which is not preferable. When the weight ratio of the polyamide component exceeds 80% by weight, it is not preferable because the fineness of the polyamide fiber tends to be insufficient. The weight ratio of the polyamide component and the aliphatic polyester component is more preferably in the range of polyamide: aliphatic polyester = 25: 75 to 75:20, most preferably polyamide: aliphatic polyester = 30: 60 to 60:30.

The method for producing the nonwoven fabric comprising the ultrafine fiber-generating composite fiber in the present invention is not limited in any way, but is short because the production method is simple, the production capacity is excellent, and the strength of the resulting artificial leather equipment is excellent. It is a preferable form that it consists of a fiber nonwoven fabric or a long fiber nonwoven fabric.

  The short fiber nonwoven fabric referred to in the present invention is obtained by extruding a melted polymer from a nozzle and cooling it, and then winding it once to make an unstretched yarn, or continuously without winding it once, in one or more stages. Short fibers that are made into a non-woven sheet integrated by cold-stretching or hot-stretching and then cutting into short fibers and mechanically entwining the web obtained by carding, cross-wrapping, etc. Nonwoven fabric is preferred.

  In addition, such short fibers can be subjected to a predetermined crimping process by a stuffing box method or an indentation heating gear method before cutting. In the case of producing a short fiber nonwoven fabric by a dry method, the number of crimps of the short fiber is preferably 5 to 50/25 mm, more preferably 10 to 30/25 mm, and the cut length of the short fiber. Is preferably 10 to 80 mm, more preferably 20 to 60 mm. That is, when the number of crimps is less than 5/25 mm, unopened fibers are likely to be unopened at the time of opening, and when the number of crimps exceeds 50/25 mm, uniform spread may not be obtained. It is not preferable.

  Moreover, when manufacturing a short fiber nonwoven fabric by the papermaking method, 1-25 mm is preferable and, as for the cut length of this short fiber, More preferably, it is 3-15 mm. If the cut length is less than 1 mm, it is difficult to make paper, and if the cut length exceeds 25 mm, it may be difficult to obtain a uniform nonwoven fabric by paper making.

  Furthermore, the long-fiber nonwoven fabric referred to in the present invention is not particularly limited, but is obtained by extruding a molten polymer from a nozzle, spinning it with a high-speed suction gas at a spinning speed of 1000 to 5000 m / min, and performing suction drawing. The fiber is opened by a known opening device, the fiber is collected on a moving conveyor to form a web, and this is a nonwoven sheet integrated by mechanically intertwining the needle punching process or the like. What was manufactured by what is called the spun bond method is preferable. The long-fiber nonwoven fabric produced by the spunbond method has high processing stability because it is excellent in mechanical strength, and can be said to be the most suitable form.

Short fiber nonwoven fabric definitive to the present invention, needle punching process in the long-fiber nonwoven fabric is preferably a needle number 200-8000 present / cm ^2. When the number of needles is less than 200 / cm ² , the desired high-precision finish cannot be obtained due to poor surface fiber density, and when it exceeds 8000 / cm ² , workability is deteriorated. At the same time, fiber damage is significant, leading to a decrease in strength. The number of needles is more preferably 500 to 7000 / cm ² , and most preferably 1000 to 6000 / cm ² .

Moreover, it is preferable that the fiber density of the nonwoven fabric after this needle punch is 0.2-0.5 g / cm < ³ > from a viewpoint of densification of the number of surface fibers. When the fiber density is less than 0.2 g / cm ³ , the surface smoothness of the sheet tends to be inferior, and this is not preferable. When the fiber density exceeds 0.5 g / cm ³ , the nonwoven fabric becomes paper-like. This is an undesirable direction because the texture becomes harder. A more preferable fiber density is 0.25 to 0.4 g / cm ³ . Further, it is also preferable to further perform water jet punching before and after the needle punching in terms of improving the entanglement of the fibers. As such water jet punching treatment, it is preferable to treat both the front and back surfaces at least once with a water pressure of 5 to 20 MPa. When such a treatment water pressure is in the range of 5 to 20 MPa, entanglement is appropriately performed and the strength of the nonwoven fabric tends to be sufficient.

By eluting removing aliphatic polyester components by alkaline solution treatment the microfine fiber-composite nonwoven fabric of the present invention, it is possible to obtain a microfibrous non-woven fabric. In addition, after the alkali solution treatment, high-speed fluid flow such as water jet punch treatment is performed in order to further increase the entanglement of the ultrafine fibers, to make the fibers finer, to improve the openability of the ultrafine fibers, and to improve the smoothness. You may implement combining a process and the stagnation process using a liquid dyeing machine, a Wins dyeing machine, a jigger dyeing machine, a tumbler, a relaxer, etc. suitably. When the high-speed fluid flow process and the stagnation process are performed in combination, it is preferable to perform the stagnation process after the high-speed fluid flow process is performed in order to suppress dimensional fluctuations during the stagnation process. As such a high-speed fluid flow treatment, a water jet punch treatment using a water flow is preferably used in terms of the working environment.

  The method for producing artificial leather according to the present invention uses such an ultrafine fiber-generating composite fiber nonwoven fabric to give a polymer elastic body before or after elution and removal of the aliphatic polyester component by treating the nonwoven fabric with an alkaline solution. It is. Furthermore, a method in which a polymer elastic body is once applied before the alkali solution treatment and the polymer elastic body is further applied after the alkali solution treatment is also preferable. Such a polymer elastic body has roles such as surface unevenness, a cushion for vibration absorption, and fiber shape maintenance.

  The polymer elastic body used in the present invention is not particularly limited. For example, polyurethane elastomer, polyurea elastomer, polyurethane / polyurea elastomer, polyacrylic acid resin, acrylonitrile / butadiene elastomer, styrene / butadiene elastomer can be used. Of these, polyurethane elastomers such as polyurethane elastomers and polyurethane / polyurea elastomers are preferred.

  As such a polyurethane, a polyol component using a polyester-based, polyether-based, or polycarbonate-based diol can be used.

  The polyester-based diol can be obtained by reacting an alkanediol with a dicarboxylic acid or an ester-forming derivative thereof under conditions employed for a normal polyester-forming reaction. Examples of such alkanediols include ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol and 1,10- Examples include decanediol. Representative examples of such dicarboxylic acids include aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid and sebacic acid, and aromatic dicarboxylic acids such as phthalic acid, terephthalic acid and isophthalic acid. These dicarboxylic acids are used alone or in a mixture of two or more. Of these, aliphatic dicarboxylic acids are preferably used. These dicarboxylic acids may be used in the form of ester-forming derivatives. Typical examples in that case include lower alkyl esters such as methyl and ethyl esters of the dicarboxylic acids exemplified above. The above dicarboxylic acids or ester-forming derivatives thereof may be used alone or in a mixture of two or more.

  Polylactone diols can also be used, and examples include poly-ε-caprolactone diol and poly-β-methyl-d-valerolactone diol. These polylactone diols are produced by ring-opening polymerization of lactones using alkylene glycol or the like as an initiator.

  Next, examples of the polyether-based diol include, but are not limited to, those having repeating units of polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

  Moreover, as said polycarbonate-type diol, what was manufactured by transesterification of alkylene glycol and carbonate ester or reaction of phosgene or a chloro formate ester and alkylene glycol, for example can be used.

  Such alkylene glycols include trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonane. Linear alkylene glycol such as diol, 1,10-decanediol, propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8 octanediol, 2,7-dimethyl- Branched alkylene glycols such as 1,8-octanediol and 2,8-dimethyl-1,9-nonanediol can be used. Further, representative examples of the carbonic acid ester include diphenyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.

  The organic diisocyanate combined with such a polymer diol constituting the polyurethane of the present invention is not particularly limited. For example, when heat resistance is important, aromatic diisocyanate such as 4,4′-diphenylmethane diisocyanate is used. If you want to suppress yellowing due to NOx or light, use an alicyclic diisocyanate such as 4,4'-dicyclohexylmethane diisocyanate or isophorone diisocyanate, or an aliphatic diisocyanate such as 1,6-hexamethylene diisocyanate. Can do. Further, a plurality of these diisocyanates can be used in combination depending on the purpose.

  The chain extender to be reacted with the polymer diol and diisocyanate is not particularly limited, and organic diols, organic diamines, hydrazine derivatives, and the like can be used.

  Examples of such organic diols include ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, 1,7-heptanediol, Aliphatic diols such as 1,8-octanediol, 1,9-nonanediol and 1,10-decanediol, alicyclic diols such as 1,4-cyclohexanediol and hydrogenated xylylene glycol, xylene glycol, etc. be able to.

  Examples of such organic diamines include ethylene diamine, isophorone diamine, xylene diamine, phenyl diamine, and 4,4'-diaminodiphenyl methane. Examples of hydrazine derivatives include hydrazine, adipic hydrazide, and isophthalic hydrazide.

  In the present invention, the polymer elastic body may further include a colorant, an antioxidant, an antistatic agent, a dispersing agent, a softening agent, a coagulation adjusting agent, a flame retardant, an antibacterial agent, and a deodorant as necessary. Additives may be blended.

  Moreover, as a solvent used for such a polymer elastic body, N, N′-dimethylformamide, dimethyl sulfoxide or the like can be preferably used. Further, an aqueous polyurethane dispersed as an emulsion in water may be used.

  The amount of the polymer elastic body applied is preferably in the range of 5 to 75% by weight as a solid content in terms of the weight ratio of the ultrafine fibers in consideration of the flexibility, surface touch, and dyeing uniformity of the artificial leather. A more preferable amount of the polymer elastic body is 7 to 70% by weight, most preferably 10 to 65% by weight.

  In addition, when a surface coating layer is provided on the surface of the artificial leather base material of the present invention by a method such as spraying, gravure, or dry surface, a natural leather-like surface feel is obtained by the effect of the ultrafine fiber layer. A sheet having the same can be obtained. Furthermore, a suede-like or nubuck-like sheet can be obtained by subjecting the surface of the artificial leather substrate of the present invention to a raising process such as buffing.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

  The evaluation methods used in the examples and the measurement conditions will be described below.

(1) Polymer viscosity MFR (melt flow rate: g / 10 min)
The MFR of aliphatic polyester and polyamide was measured based on ASTM D1238 (measurement temperature 240 ° C., measurement load 2.16 kg load), and 10 measurements were performed for each sample, and the average value was calculated after the decimal point. The one rounded off was taken as the MFR of each polymer.

(2) Weight average molecular weight The weight average molecular weight of the polylactic acid resin was calculated | required with the following method.
Tetrahydrofuran was mixed with the chloroform solution of the sample to obtain a measurement solution, which was measured at 25 ° C. using a gel permeation chromatograph (GPC) Waters 2690 manufactured by Waters, and the weight average molecular weight was determined in terms of polystyrene. Three measurements were performed for each sample, the average value was calculated, and the weight average molecular weight was rounded off to the nearest thousand.

(3) Melting point Using a PerkinElmer DSC-7, the peak top temperature indicating the melting of the polymer at 2nd run was taken as the melting point of the polymer. At this time, the rate of temperature increase was 16 ° C./min, and the sample amount was 10 mg.

(4) Single fiber fineness (decitex)
The single fiber fineness of the fibers constituting the nonwoven fabric was determined by the following method.
Ten small sample pieces are randomly collected from the nonwoven fabric, photographed at a magnification of 500 to 3000 times with a scanning electron microscope or the like, and the cross-sectional area of a total of 100 fibers, 10 from each sample, is measured and averaged. The value was calculated, converted into the fiber diameter of a circular fiber, and corrected by the density of the polymer.

(5) Weight per unit area (g / m ² ):
Three samples having a size of 50 cm in length and 50 cm in width were collected from the nonwoven fabric, each weight was measured, and the average value of the obtained values was converted per unit area and calculated by rounding off the first decimal place. .

(6) Spinnability The spinnability at the time of melt spinning the polymer for producing a nonwoven fabric was evaluated visually. Those having no abnormality in the yarn breakage or the composite state of the polymer were regarded as acceptable (◯), and those in which abnormality was observed were regarded as unacceptable (x).

(7) Tensile strength (N / cm)
Perform a tensile test on a sample size, width 1 cm × length 20 cm with a constant speed extension type tensile tester for 20 samples in the sheet longitudinal direction and the transverse direction under the conditions of a holding interval of 10 cm and a tensile speed of 10 cm / min. The maximum strength when the sample was pulled until it broke was taken as the tensile strength, and the average value in the longitudinal and lateral directions of the sheet was calculated by rounding off the first decimal place.

(8) Texture Ten panelists evaluated by sensory evaluation, ○: soft and good, Δ: slightly hard, ×: hard and bad, and 6 or more were evaluated as “good”.

Example 1
Poly (L-lactic acid) (PLA, optical purity of 99.5% or higher) (50 wt%) having a melting point of 170 ° C. and MFR of 155 g / 10 min, and nylon 6 (N6, 50 having an MFR of 92 g / 10 min at a melting point of 215 ° C. (Weight%), PLA is melted in an extruder at 235 ° C and N6 is 240 ° C, spun from a 16-part die at a die temperature of 240 ° C, and then spun at a spinning speed of 2500 m / min by an ejector. The web collected on the moving net conveyor is heat-treated with an embossing roll and a flat roll having a crimping area of 10% under conditions of a temperature of 85 ° C. and a linear pressure of 30 kg / cm, and a temporary adhesive sheet Got.

Next, an oil agent mainly composed of a fatty acid metal salt and silicone was applied to the temporary adhesive sheet in an amount of 1.5 wt% based on the fiber weight, and then a needle depth of 8 mm was obtained using a needle punch machine in which a 1-barb needle needle was implanted. Was punctured at 3000 / cm ² to obtain an entangled nonwoven fabric.

  This nonwoven fabric was impregnated with a polyvinyl alcohol solution having a liquid temperature of about 85 ° C. and a concentration of about 12%, constricted with a nip roll, applied with 20% polyvinyl alcohol in solid content with respect to the fiber weight, and then dried. Thereafter, the sheet-like material was impregnated in a DMF solution of polyester / polyether polyurethane and squeezed with a nip roll to give 30% polyurethane in terms of solid content with respect to the fiber weight of N6. The polyurethane was coagulated with a% DMF aqueous solution, and DMF and polyvinyl alcohol were removed with hot water at about 85 ° C. The surface of the sheet was ground with sandpaper to form napped.

The sheet-like material on which the naps were formed was treated with a 4% aqueous sodium hydroxide solution at 80 ° C. for 30 minutes and dried to elute PLA to generate ultrafine fibers made of N6 to obtain artificial leather. The single fiber fineness of the obtained ultrafine fiber composed of N6 was 0.2 dtex, and the basis weight of the artificial leather was 230 g / m ² .

(Example 2)
A temporary adhesive sheet obtained in the same manner as in Example 1 was given 1.5 wt% of a fatty acid metal salt and a silicone-based oil as the main components, and then a 1-barb needle needle was implanted. Needle punch is performed at 1800 needles / cm ² at a needle depth of 8 mm with a needle punch machine, and then water jet punching is performed at a passing speed of 3 m / min. To obtain an entangled nonwoven fabric.

  The entangled nonwoven fabric was impregnated with a polyvinyl alcohol solution having a liquid temperature of about 85 ° C. and a concentration of about 12%, squeezed with a nip roll, applied with a solid content of 20% polyvinyl alcohol with respect to the fiber weight, and then dried. . Subsequently, the obtained sheet-like material was treated with a 4% sodium hydroxide aqueous solution at 80 ° C. for 30 minutes and dried to elute PLA to generate ultrafine fibers composed of N6, thereby obtaining an ultrafine fiber nonwoven fabric.

This extra fine fiber nonwoven fabric is impregnated in a DMF solution of polyester / polyether polyurethane and squeezed with a nip roll to give 30% polyurethane in solid content with respect to the fiber weight, and a 30% DMF aqueous solution with a liquid temperature of 35 ° C. Then, the polyurethane was coagulated and DMF and polyvinyl alcohol were removed with hot water at about 85 ° C. The surface of the sheet-like material was ground with sandpaper to form napped hairs to obtain artificial leather. The single fiber fineness of the obtained ultrafine fiber composed of N6 was 0.2 dtex, and the basis weight of the artificial leather was 230 g / m ² .

(Example 3)
N6 (50% by weight) and PLA (50% by weight) as in Example 1 are used as raw materials, PLA is 235 ° C., N6 is 240 ° C., melted in an extruder, and divided into 16 hollow parts at a base temperature of 240 ° C. After spinning from the die, the web spun by an ejector at a spinning speed of 2300 m / min and collected on a moving net conveyor is an embossing roll and a flat roll with a crimping area of 10%. Heat treatment was performed under conditions of a temperature of 85 ° C. and a linear pressure of 30 kg / cm to obtain a temporary adhesive sheet.

  Next, this temporary adhesive sheet was subjected to needle punching and water jet punching in the same manner as in Example 2 to obtain an entangled nonwoven fabric.

This entangled nonwoven fabric is impregnated in a polyether-based aqueous polyurethane emulsion, squeezed with a nip roll, and 40% solid polyurethane is given to the fiber weight of N6, heat-gelled and solidified, and then this sheet The shaped product was treated with a 4% aqueous sodium hydroxide solution at 80 ° C. for 30 minutes and dried to elute PLA to generate ultrafine fibers composed of N6 to obtain an ultrafine fiber nonwoven fabric. The surface of the ultrafine fiber nonwoven fabric was ground with sandpaper to form napped hairs to obtain artificial leather. The single fiber fineness of the obtained ultrafine fiber made of N6 was 0.1 dtex, and the basis weight of the artificial leather was 245 g / m ² .

( Reference Example 4)
N6 (50% by weight) and PLA (50% by weight) as in Example 1 were used as raw materials, PLA was melted in an extruder at 235 ° C. and N6 was 240 ° C., respectively. After spinning and applying an oil agent, spinning was performed at a spinning speed of 900 m / min, and the undrawn yarn was wound up once. This was hot-drawn 3.8 times with a heating roll at 90 ° C., and 14 pcs / 25 mm of mechanical crimps were applied to the obtained drawn yarn using a stuffing box, cut to a length of 51 mm and short. Fiber was obtained. Using this short fiber as raw cotton, carding and cross-wrapping are performed to produce a web, and then needle punching is performed at 3000 needles / cm ² at a needle depth of 8 mm with a needle punch machine in which a needle needle of 1 barb is implanted. An entangled nonwoven fabric was obtained.

  This nonwoven fabric was impregnated with a polyvinyl alcohol solution having a liquid temperature of about 85 ° C. and a concentration of about 12%, constricted with a nip roll, applied with 30% polyvinyl alcohol in solid content with respect to the fiber weight, and then dried. Subsequently, the obtained sheet-like material was treated with a 4% sodium hydroxide aqueous solution at 80 ° C. for 30 minutes and dried to elute PLA to generate ultrafine fibers composed of N6, thereby obtaining an ultrafine fiber nonwoven fabric.

This extra fine fiber nonwoven fabric is impregnated in a DMF solution of polyester / polyether polyurethane and squeezed with a nip roll to give 30% polyurethane in solid content with respect to the fiber weight, and a 30% DMF aqueous solution with a liquid temperature of 35 ° C. Then, the polyurethane was coagulated and DMF and polyvinyl alcohol were removed with hot water at about 85 ° C. The surface of the sheet-like material was ground with sandpaper to form napped hairs to obtain artificial leather. The single fiber fineness of the obtained ultrafine fiber composed of N6 was 0.2 dtex, and the basis weight of the artificial leather was 250 g / m ² .

( Reference Example 5)
PLA (optical purity 99.5% or more) (60 wt%) with a melting point of 170 ° C and MFR 105g / 10min as sea component, N6 (40 wt%) with melting point 215 ° C and MFR 92g / 10min as island component The PLA was melted in an extruder at 235 ° C. and N6 was 240 ° C., respectively, spun from a 36 island island-type die at a die temperature of 240 ° C., oiled, and spun at a spinning speed of 900 m / min. The drawn yarn was wound up once. This was hot-drawn 3.8 times with a heating roll at 90 ° C., and 14 pcs / 25 mm of mechanical crimps were applied to the obtained drawn yarn using a stuffing box, cut to a length of 51 mm and short. Fiber was obtained. Using this short fiber as raw cotton, carding and cross-wrapping are performed to produce a web, and then needle punching is performed at 3000 needles / cm ² at a needle depth of 8 mm with a needle punch machine in which a needle needle of 1 barb is implanted. An entangled nonwoven fabric was obtained.

  This nonwoven fabric was impregnated with a polyvinyl alcohol solution having a liquid temperature of about 85 ° C. and a concentration of about 12%, constricted with a nip roll, applied with 30% polyvinyl alcohol in solid content with respect to the fiber weight, and then dried. Subsequently, the obtained sheet-like material was treated with a 4% sodium hydroxide aqueous solution at 80 ° C. for 30 minutes and dried to elute PLA to generate ultrafine fibers composed of N6, thereby obtaining an ultrafine fiber nonwoven fabric.

This extra fine fiber nonwoven fabric is impregnated in a DMF solution of polyester / polyether polyurethane and squeezed with a nip roll to give 30% polyurethane in solid content with respect to the fiber weight, and a 30% DMF aqueous solution with a liquid temperature of 35 ° C. Then, the polyurethane was coagulated and DMF and polyvinyl alcohol were removed with hot water at about 85 ° C. to obtain an artificial leather base material. The surface of the obtained artificial leather base material was ground with sandpaper to form napped hairs to obtain artificial leather. The single fiber fineness of the obtained ultrafine fiber made of N6 was 0.01 dtex, and the basis weight of the artificial leather was 210 g / m ² .

( Reference Example 6)
Polyurethane having a thickness of 50 μm obtained by the same technique as in Reference Example 5 and colored with a white pigment on one side of an artificial leather base material having a single fiber fineness of 0.01 dtex and a basis weight of 180 g / m ^2. The film was bonded using a two-component urethane adhesive, dried at 100 ° C. for 1 minute, and after sufficient crosslinking reaction, the release paper was peeled off to obtain an artificial leather having a basis weight of 213 g / m ² . .

The properties and the like of the obtained artificial leather are as shown in Table 1. However, in the production of the artificial leather of Examples 1 , 3 and Reference Examples 4 and 5, the combination of the composite polymers is appropriate. Also showed good spinnability. Moreover, although any artificial leather obtained in Examples 1 to 3 and Reference Examples 4 to 6 uses a polylactic acid resin having a low environmental impact as a raw material, the tensile strength is 50 N in both length and width. An excellent value of / cm or more was exhibited, and the texture evaluation by the monitor was also excellent.

(Comparative Example 1)
The PLA used in Example 1 (30% by weight) and nylon 6 (N6, 70% by weight) having a melting point of 215 ° C. and an MFR of 32 g / 10 min were used as raw materials. PLA was 235 ° C. and N6 was 240 ° C., respectively. After spinning at a die temperature of 240 ° C. and spinning from a 16-part die, spinning was carried out with an ejector at a spinning speed of 2800 m / min. As a result, yarn breakage occurred frequently, and the sheet could not be collected due to poor yarn production.

(Comparative Example 2)
Polyethylene terephthalate (PET, 55% by weight) as an island component and polystyrene (45% by weight) as a sea component, both melted in an extruder at 285 ° C., and from a 36 island island cap at a base temperature of 285 ° C. After spinning and applying an oil agent, spinning was performed at a spinning speed of 1200 m / min, and the undrawn yarn was wound up once. This was hot-drawn 2.8 times with a heating roll at 90 ° C., and the resulting drawn yarn was subjected to mechanical crimping of 14 pieces / 25 mm using a stuffing box, cut into a length of 51 mm and short. Fiber was obtained. Using this short fiber as raw cotton, carding and cross-wrapping are performed to produce a web, and then needle punching is performed at 2500 needles / cm ² at a needle depth of 8 mm with a needle punch machine in which a needle needle of 1 barb is implanted. An entangled nonwoven fabric was obtained.

  This entangled nonwoven fabric was impregnated with a polyvinyl alcohol solution having a liquid temperature of about 85 ° C. and a concentration of about 12%, squeezed with a nip roll, applied with 30% polyvinyl alcohol in solid content with respect to the fiber weight, and then dried. Next, the obtained sheet-like material was treated with a trichlorethylene solution to elute polystyrene to obtain an ultrafine fiber nonwoven fabric made of PET.

This ultra-fine fiber nonwoven fabric is impregnated in a DMF solution of polyester / polyether polyurethane and squeezed with a nip roll to give 23% solids polyurethane with respect to the fiber weight, and a 30% DMF aqueous solution with a liquid temperature of 35 ° C. Then, the polyurethane was coagulated and DMF and polyvinyl alcohol were removed with hot water at about 85 ° C. The surface of the sheet-like material was ground with sandpaper to form napped hairs to obtain artificial leather. The single fiber fineness of the obtained ultrafine fiber made of PET was 0.01 dtex, and the basis weight of the artificial leather was 210 g / m ² .

(Comparative Example 3)
N6 used in Example 1 as an island component (60% by weight) and polyethylene as a sea component (40% by weight) were mixed and melted in an extruder at 270 ° C., and a round hole cap at a base temperature of 270 ° C. After spinning and applying an oil agent, spinning was performed at a spinning speed of 500 m / min, and the undrawn yarn was wound up once. This was hot-drawn 2.8 times with a heating roll at 90 ° C., and the resulting drawn yarn was subjected to mechanical crimping of 14 pieces / 25 mm using a stuffing box, cut into a length of 51 mm and short. Fiber was obtained. Using this short fiber as raw cotton, carding and cross-wrapping are performed to produce a web, and then needle punching is performed at 1800 needles / cm ² at a needle depth of 8 mm with a needle punching machine in which a needle needle of 1 barb is implanted. An entangled nonwoven fabric was obtained.

This entangled nonwoven fabric is impregnated with a polyester / polyether polyurethane DMF solution, squeezed with a nip roll, and 40% solid polyurethane is added to the N6 fiber weight, and a 30% DMF with a liquid temperature of 35 ° C. The polyurethane was coagulated with an aqueous solution, and DMF was removed with hot water at about 85 ° C. Then, this sheet-like material was treated with a toluene solution at 85 ° C. to elute polyethylene to generate ultrafine fibers made of N6, thereby obtaining an artificial leather base material. The surface of the base material was ground with sandpaper to form napped hairs to obtain artificial leather. The single fiber fineness of the obtained ultrafine fiber composed of N6 was 0.002 dtex, and the basis weight of the artificial leather was 225 g / m ² .

  The characteristics and the like of the obtained artificial leather are as shown in Table 1. However, for Comparative Example 1, the combination of the selected PLA and N6 viscosities was inappropriate, resulting in poor spinnability and sheet collection. could not. The artificial leathers of Comparative Examples 2 and 3 had no operational problems such as spinnability, and had good strength and texture. In Comparative Example 2, trichloroethylene, an organic solvent, was used to elute and remove polystyrene. It was necessary to carry out, and it was a thing with high environmental impact. Further, in Comparative Example 3, it was necessary to use high-temperature toluene for elution and removal of polyethylene, and the environmental load was large.

Claims (2)

Composite spinning of an aliphatic polyester having a melt flow rate (MFR) of 20 to 300 g / 10 min measured based on ASTM D1238 (measuring temperature 240 ° C., measuring load 2.16 kg load) and polyamide satisfying the following relationship: Before or after the spunbonded nonwoven fabric composed of the split-type ultrafine fiber-generating composite fiber obtained by treating with an alkali solution to extract and remove the aliphatic polyester, to give a polymer elastic body A method for producing an artificial leather base material .
(MFR of aliphatic polyester) / (MFR of polyamide) = 0.3 to 3.0 The method for producing an artificial leather base material according to claim 1, wherein a needle punching process and a water jet punching process are performed when the spunbonded nonwoven fabric is produced.