JP2000080572A - Artificial leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an artificial leather having increased sewing yield by solving the problems on poor insertion properties due to the gloss difference caused by teaseling direction. SOLUTION: This artificial leather is prepared by applying a polymeric elastomer to an ultrafine fiber-entangled web body and has an extremely fine fiber-teaseled face at least on one face. The teaseled face is measured its angle- changing reflection as it is rotated from 0 deg. to 180 deg. to draw the angle-changing reflection curve by means of an automatic angle-changing reflection photometer, thus has an R-value of <=25% according to the following formula: R=(R1-R 3)/(R1-R2)×100 (R1 is the reflection at 0 deg., R2 is the minimum reflection in the range from 0 deg. to 180 deg., and R3 is the reflection at 180 deg.).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial leather in which the direction of the napped surface of the artificial leather is minimized.

[0002]

2. Description of the Related Art Conventional artificial leather manufacturing technology having naps composed of an entangled body of ultrafine fibers and a polymer elastic body has a strong nap orientation in the final product. There was a difference and it was necessary to sew together in the same direction. Therefore, the fabric cannot be used effectively, and the sewing yield is limited.

[0003]

SUMMARY OF THE INVENTION In view of the above problems of the conventional artificial leather, the present invention solves the problem of poor insertability in sewing based on the difference in gloss of the surface due to the direction of the nap, and improves the sewing yield. To provide artificial leather.

[0004]

The present invention employs the following means in order to solve the above-mentioned problems. That is, in the artificial leather of the present invention, a polymer elastic body is provided to an entangled body made of ultrafine fibers, and at least one surface of the artificial leather has a napped surface made of ultrafine fibers, the napped surface is reduced to 0 by an automatic goniophotometer. The R value obtained by the following equation from the deflection angle reflection curve measured by rotating from 180 degrees to 180 degrees is 25% or less.

R value (%) = (R1−R3) / (R1−R2) × 100 (where the amount of reflected light at R1: 0 degrees, R2: 0 degrees
Minimum reflected light amount in the 180-degree rotation category, R3: 180
Shows the amount of reflected light in degrees. )

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is directed to an artificial leather which solves the above-mentioned problem, that is, the problem of poor insertion property in sewing based on the difference in gloss of the surface due to the direction of the nap, and improves the sewing yield. When the specific reflection state of light on the raised surface, that is, the difference in surface gloss was reduced as much as possible, it was surprisingly found that such a problem could be solved all at once.

[0007] An artificial leather in which an entangled body made of microfibers is provided with a polymer elastic body and has a raised surface made of microfibers on at least one surface is formed by, for example, using sandpaper to remove the sheet surface from the sheet in a raising process. Bristles are generated by buffing in the vertical direction. At this time, directionality is given to the nap by the buffing direction. Here, the direction in which the nap is likely to fall when the nap is rubbed with a brush is defined as a forward direction, and the direction in which the nap occurs occurs is defined as a reverse direction.

A method for measuring a deflection reflection curve according to the present invention will be described with reference to a model diagram shown in FIG.

First, an automatic goniophotometer (GP-) equipped with a halogen lamp (12 V, 50 W) as a light source lamp.
1R, GP-200 type), the incident light (i) is directed toward the center point (O) with respect to the normal (N) of the surface of the artificial leather (S), and the incident angle (α) is reflected at 60 degrees. The light receiving angle (γ) of the light (R) is set to 60 degrees. Then, the material is nylon (21
0D-15f, manufactured by Toray) filament, vertical warp yarn × ground weft yarn = 85 × 57 yarns / inch, pile number = 594
Stock / 25 mm ² , pile length = 2.6 mm (thickness from back of fabric to the tip of pile) as double pile fabric, heat-set, and brush fabric in which pile is inclined in one direction is weighed 400 g. A piece having a plane having a width of 10 × 10 cm and fixed by weight is placed on the nap surface of artificial leather and stroked at a speed of 5 m / sec in the positive direction of the nap. This operation is repeated five times to obtain a measurement sample.

[0010] The above conditions are generally such that humans remove dust adhering to clothes using an etiquette brush. As shown in FIG.
Is set to be perpendicular to the incident light (i).
The sample angle at this position is set to 0 degree.

At this time, the artificial leather is rotated continuously by 180 degrees in the direction of the arrow at the same time as the light source is illuminated, and the reflected light (R)
Is measured continuously to obtain a deflection reflection curve.

However, depending on the hue of the artificial leather, the amount of reflected light on the deflective reflection curve naturally differs even with the same amount of light. Therefore, the reference conditions for obtaining the R value (%) shown in the present invention are those measured under the following conditions.

First, the full scale is adjusted to 100% by using a white plate of magnesium fluoride and adjusting the light amount and the sensitivity of the apparatus. Next, for example, when a dark-colored artificial leather product is set under the above conditions, the amount of reflected light naturally changes to a lower position. Also, when a light-colored artificial leather product is set under the above conditions, the amount of reflected light naturally goes to a higher position than a dark-colored product. In order to eliminate such a difference due to the hue of the artificial leather and to evaluate the same standard, the positive direction (a) of the nap is perpendicular to the incident light (i) (the sample angle is 0).
After adjusting the aperture of the light source and the sensitivity of the device so that the amount of reflected light when it is set so as to be 50% of the white plate of magnesium fluoride (X), start the measurement, and A bending reflection curve as shown in FIG. Using this, the R value (%) is determined by the following formula.
However, even if it is an artificial leather, since there are some spots on the surface, the number of measurement samples is set to 5, and the average value is obtained.

R value (%) = (R1−R3) / (R1−R2) × 100 (where, the reflected light amount at R1: 0 degrees, R2: 0 degrees
Minimum reflected light amount in the 180-degree rotation category, R3: 180
Shows the amount of reflected light in degrees. ) A more detailed description will be given using an example of a deflection reflection curve. In the present invention, R1 is
It indicates R1 on the deflection reflection curve in FIG. 2, that is, the amount of reflected light at that time when the light source hits the upright in the positive direction at 90 degrees. Further, R2 refers to the lowest amount of reflected light when the artificial leather is continuously rotated at a constant speed up to 180 degrees in the direction of the arrow in FIG. 1, and R3 refers to the direction of the napped hair when rotated 180 degrees, ie, R1. This is the amount of reflected light at a position completely opposite to that of FIG.

The present inventors assume that the difference in the amount of light of (R1-R2) is 100% in this deflection angle reflection curve, and that (R1-R2)
The R value (%) obtained by determining what percentage of the light amount difference in 3) corresponds to
25% or less, preferably 20% or less, more preferably 1% or less
When it is 5% or less, the direction of the fabric is changed, and even if the sewing machine is sewn, the difference in gloss on the nap surface is small, the difference in color density is visually reduced, the fabric can be used effectively, and the sewing yield is improved. It was found. An artificial leather having a polymer elastic body having such an R value (%) and having a nap surface made of microfibers on at least one side may be an entangled body made of microfibers, for example, at least two components having different properties from each other. Using a polymer of the above, a composite fiber formed by composite spinning or mixed spinning is formed into a web, and subjected to an entanglement means such as a needle punch or a water jet punch to form a nonwoven fabric. Thereafter, at least one component is dissolved and removed or physically, It is obtained by peeling and dividing by chemical action.

The form of the conjugate fiber and the ultrafine fiber is not particularly limited. The above-mentioned conjugate fiber is, for example, nylon 6 or nylon 6 as an ultrafine fiber forming polymer.
6, Polyesters such as nylon 12, nylon 12, copolymerized nylon and the like, polyethylene terephthalate, copolymerized polyethylene terephthalate, polybutylene terephthalate, copolymerized polybutylene terephthalate, polypropylene terephthalate and copolymers thereof, and dissolved or removed or physically removed Delamination by chemical and chemical action,
As the dividable polymer, the above polyamides, polyesters, polyethylene, polystyrene, polyolefins such as polypropylene and the like are used, and among these polymers, the cross-sectional formability of ultrafine fibers, spinnability, stretchability, etc. are considered. You can combine them. In addition, in the ultrafine fiber forming polymer, if necessary, a light-resistant agent, a pigment, a matting agent,
Even if additives such as an antistatic agent and a flame retardant are included, the effect of the present invention is not impaired by the presence or absence of such additives.

The ultrafine fibers in the present invention may be in the form of a single fiber, but preferably in the form of a fiber bundle. The number of such bundles cannot be unequivocally limited due to the entanglement with the thickness of the ultrafine fibers, but is preferably at least 5, more preferably 15 or more, and particularly preferably 30 or more. The average fiber thickness of the ultrafine fibers is preferably from 0.001 dtex to 0.1 dtex from the viewpoints of the texture of the artificial leather, surface touch, coloring, and the denseness of the nap described later. It is preferred to obtain the effect of the present invention by combining the microfiber bundles in such a manner that the finer fiber bundles are reduced as the average fiber thickness increases, and the microfine fiber bundles are increased as the average fiber thickness decreases. When the average fiber thickness is less than 0.001 dtex, the strength of the fiber is reduced, and the nap is easily cut during buffing. On the other hand, when the average fiber thickness is more than 0.1 dtex, the nap is short and hard to cut uniformly, resulting in uneven nap. Effect is difficult to obtain.

A polymer elastic body is provided to the entangled body formed by such ultrafine fibers, and the polymer elastic body is not particularly limited. Examples thereof include polyester diols and polyether diols. Or a combination of polycarbonate diols or the like, alone or in combination, is preferably used from the viewpoint of the texture of artificial leather and surface touch. If necessary, additives such as a colorant, an antioxidant, an antistatic agent, a dispersant, a softener, and a coagulation regulator may be added to the elastic body.

The artificial leather of the present invention has an R value (%) of not more than 25% as shown in FIG. 3 and, when the sample surface is further rotated around 90 degrees, the reflection curve shown in FIG. The characteristic feature is that there is almost no significant valley between two reflected light amount changes around 90 degrees. This means that there is almost no change in the amount of reflected light even at around 90 degrees, and a difference in color density hardly occurs.

It is preferable that the artificial leather having the above-mentioned properties has an increased apparent density and a fiber-rich surface as much as possible. The standard is preferably 0.3 g / cm ³ or more, more preferably 0.4 g / cm ³ or more. / cm ³ or more is good. Means for increasing the apparent density of the ultrafine fibers include increasing the fiber shrinkage of the conjugate fiber that generates the ultrafine fibers, increasing the area shrinkage of the entangled body, and then compressing it, a solvent or swelling agent for the polymer elastic body. Can be achieved by appropriately combining a method of applying to the sheet and then compressing or a method of applying a solvent or a swelling agent of a polymer elastic material to the raised hair surface and compressing it.

When the apparent density of the artificial leather is less than 0.3 g / cm ³ , the direction of the nap becomes sharp and the elastic polymer tends to be easily exposed on the surface, as shown in FIG. At about 90 degrees on the reflection curve, two valleys of change in the amount of reflected light occur, and the direction is such that the color density difference is easily visible to the naked eye. The change in the amount of reflected light changes depending on the napped state of the artificial leather surface. The application of raised hair to the surface of artificial leather is achieved by buffing at least one surface of a sheet provided with a polymer elastic body to an entangled body of ultrafine fibers using, for example, sandpaper, so that the artificial leather has a raised surface made of ultrafine fibers. Is obtained. In order to enhance the effect of the present invention, it is preferable to shorten the bristles of the ultrafine fibers uniformly. The nap length is preferably 1 mm or less, more preferably 0.1 mm.
5 mm or less is good. If the nap length exceeds 1 mm, the directionality of the nap becomes sharp and the R value (%) tends to increase.
Further, it is preferable that the nap lengths of the ultrafine fibers of the entire bundle are uniform and short, like a velvet pile, compared to the brush-like nap state. Means for obtaining such a napped state include, for example, increasing the buffing speed, reducing the coating of sandpaper, or increasing the adhesion between the microfiber and the polymer elastic body, and then buffing, or It is preferable to apply fine inorganic fine particles with a brush to increase the frictional resistance, and then perform a raising treatment at a high speed by appropriately combining methods such as buffing through. However, as a general tendency, when the ultrafine fibers are thick, the number of bundles is large, and the nap is short, the texture and touch of artificial leather tend to be inferior. To eliminate such quality defects and to provide the characteristic values of the present invention, for example,
When the ultrafine fiber-forming polymer is a polyester or a copolymer thereof before or after dyeing, the ultrafine fibers are reduced to an appropriate category with an alkaline solution, by opening the gap between the naps, and narrowing the nap tips, Alternatively, in the case of polyamides, by pre-treating with a swelling agent and appropriately selecting the conditions of rubbing treatment for dyeing, the above-mentioned product defects can be alleviated and the R value (%) of artificial leather can be reduced.

The artificial leather of the present invention is effective not only in the field of clothing but also in the field of materials such as furniture, bags, shoes, car seats, etc., because the directionality of the fabric is small and the sewing yield is improved. . In the field of materials, more powerful products are required than in the field of clothing. In order to enhance the product strength and simultaneously impart the effects of the present invention, a polymer elastic body is imparted to a sheet in which an entangled body made of microfibers and a woven or knitted fabric are entangled and integrated, and at least one surface is made of napped fibers From the bending angle reflection curve measured by rotating the napped surface by 0 to 180 degrees with an automatic bending angle photometer,
Artificial leather having a value of 25% or less is preferred. Such artificial leather structure is formed by laminating a web of the above-mentioned composite fiber or a web obtained by a papermaking method on a woven or knitted fabric, and entangled and integrated by a needle punch, a water jet punch, or an entanglement process combining these. It becomes something. As a lamination method, a method of laminating and knitting a woven or knitted fabric on both sides or one side of the web or laminating and entanglement on one side, and further laying a plurality of the entangled bodies again and entanglement processing, A slicing method or the like is used.

As the yarn type constituting the woven or knitted fabric, filament yarn, spun yarn, blended yarn of filament and short fiber, and the like can be used, and there is no particular limitation. The types of woven or knitted fabrics include weft knitting represented by warp knitting and tricot knitting, lace knitting and various knittings based on those knitting methods, or plain knitting, twill weaving, satin weaving and their weaving methods. Any of various types of woven fabrics can be employed and is not particularly limited.

Depending on the type of yarn, when the entanglement between the conjugate fiber and the woven or knitted fabric is strengthened by needle punching, the yarn may be easily cut.
It is preferable that these yarn types are strong twist yarns.

The number of twists of such a strong twist yarn is 500 T
/ M or more and 4500 T / m or less, more preferably 1500 T / m or more, and most preferably 2000 T / m or more.
m or more. If it is less than 500 T / m, the single yarns constituting the yarn are insufficiently squeezed, so that the yarn is liable to be caught on the needle and damaged, and even if the number of twists is too large, the fiber becomes too hard and the product feels soft. Therefore, the upper limit is preferably set to 4000 T / m or less.

As the fibers constituting the woven or knitted fabric, polyesters, polyamides, polyethylene, polypropylene and copolymers thereof are used. Among them, polyesters, polyamides, and copolymers thereof are preferably used alone or in combination.

When such a woven or knitted fabric is inserted,
Although the feeling of the product tends to be hard, it is preferable that the fibers constituting the knitted fabric be slimable conjugate fibers in order to make the product more flexible. The slimable type conjugate fiber is a conjugate fiber which can be ultra-thinned by dissolving and removing at least one component or by peeling and dividing by physical or chemical action, and the cross-sectional shape of the conjugate fiber is particularly limited. Not something.

For example, as the polymer forming the ultrafine fiber, for example, nylon 6, nylon 66, nylon 1
2, polyamides such as copolymerized nylon, polyethylene terephthalate, copolymerized polyethylene terephthalate,
Polyesters such as polybutylene terephthalate and copolymerized polybutylene terephthalate can be used. As the polymer to be removed by dissolution or to be separated and divided by physical or chemical action, the above-mentioned polyamides, polyesters, polyolefins such as polyethylene, polystyrene and polypropylene can be used. Among these, the combination may be made in consideration of the cross-sectional formability, spinnability, stretchability and weaving property of the ultrafine fibers, sea-removability with the composite fibers used for the web, and the like. In addition, stabilizers, matting agents, antistatic agents,
Even if an additive such as a flame retardant is included, the effect of the present invention is not impaired. After the above composition, additives such as a coloring agent, an antioxidant, an antistatic agent, a dispersant, a softener, a coagulation regulator, a flame retardant, an antibacterial agent, and a deodorant are added to the polymer elastic body as necessary. And the artificial leather of the present invention can be obtained by finishing the ultrafine fiber thickness, the number of bundles, the ultrafine fiber density and the nap length under the conditions described above.

[0029]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples. However, the scope of the present invention is not limited.
There is no restriction. Rather, they bring about the following applications and developments.

Example 1 Polyethylene terephthalate as island component, polystyrene as sea component, island / sea ratio = 30/70% by weight, 36 islands,
Using a staple of a polymer cross-arranged fiber having a denier of about 4 d, a cut length of about 51 mm, and a shrinkage of about 12 peaks / in, the staple is made into a web with a card / cloth wrapper, and needle punched to a weight of 790 g / An m ² felt was made.

The felt was shrink-treated, dried, polyvinyl alcohol was applied, dried, immersed in trichlene, and pressed with a mangle, followed by drying. This sheet was impregnated with a polyester-polyether-based polyurethane as a solid content in an amount of about 30 parts per island fiber, and was wet-solidified.

Then, it is immersed in a 90% by weight aqueous solution of dimethylformamide and compressed with a clearance of about half the thickness, immersed in water, removed of the solvent, dried, and dried to obtain polyethylene having an average fiber thickness of about 0.04 dtex. A sheet was obtained in which a polymer elastic body was added to an entangled body of an ultrafine fiber bundle of terephthalate. This sheet was cut in half in the thickness direction, and the cut surface was subjected to a raising treatment with a 400-mesh sandpaper to produce a green fabric. Next, this green machine is put into a circular dyeing machine, subjected to an alkali treatment so that the loss rate of the ultrafine fibers is 4%, and once taken out of the circular dyeing machine, the feeding direction is reversed, and the sheet is put in again. Dyeing into a brownish color using a disperse dye, finishing, and further applying a tumbler-type rubbing machine and drying at the same time, the apparent density is 0.41 g / cm ³ , and the nap length is about 0.7 mm. Artificial leather was obtained. Cut this artificial leather into vertical x horizontal = 5 x 5 cm, and brush the napped surface in the forward direction with a brush.
After stroking, the napped surface is turned to 0 degree by an automatic goniophotometer.
Rotation was performed continuously by 180 degrees, and the deflection reflection curve was measured. The R value obtained from the variable angle reflection curve was 15%, and had almost no valley between two reflected light amount changes at around 90 degrees on the reflection curve as shown in FIG. Two pieces of this artificial leather, vertical x horizontal = 30 x 10 cm, were collected, one was turned 180 degrees, sewn in the vertical direction, and the difference in color density on the napped surface was determined with the naked eye. Met. When the woman's jacket was sewn with this sheet, it was confirmed that the yield rate was improved by about 20%. Example 2 A web using staples of the same polymer interconnected fibers as in Example 1 was used to prepare polyethylene terephthalate 75D-7.
2f, it was laminated on a plain woven fabric (having a basis weight of 70 g / m ² ) using raw yarn false twisted yarn having a twist of 2500 T / m, and was subjected to needle punching to prepare a felt having a basis weight of 780 g / m ² . Thereafter, the treatment was performed under the same conditions as in Example 1, and the average fiber thickness was about 0.04 dte.
x, an apparent density of 0.44 g / cm ³ , and a nap length of about 0.
7 mm of artificial leather was obtained.

The R value obtained from the deflection curve obtained by measuring the artificial leather in the same manner as in Example 1 was 12%, and the two reflected light amounts at around 90 ° on the same reflection curve as in Example 1. It had few valleys of change. As in Example 1, the difference in color density in the naked eye judgment after the sewing was also very small.

Comparative Example 1 The island component was polyethylene terephthalate, the sea component was polystyrene, the island / sea ratio was 80/20% by weight, and the number of islands was 16
Using a staple of a polymer inter-arrayed fiber having a denier of about 4 d, a cut length of about 51 mm, and a shrinkage of about 12 peaks / in, the staple is made into a web with a card / cloth wrapper, and is punched with a basis weight of 520 g / An m ² felt was made. This felt is shrunk and dried,
After applying polyvinyl alcohol and drying, it was immersed in trichlene, squeezed with a mangle, and dried. In this sheet, a polyester-polyether-based polyurethane was used as a solid component and the solid content was about 30 per island fiber.
Impregnation so as to become a part, wet coagulation, solvent removal,
After drying, a sheet was obtained in which an entangled body of an ultrafine fiber bundle of polyethylene terephthalate having an average fiber thickness of about 0.23 dtex was provided with a polymer elastic body. This sheet was cut in half, and the non-cut surface was raised with a 240 mesh sandpaper to produce a green fabric.

Next, the green fabric was put into a circular dyeing machine, dyed brown using a disperse dye, and subjected to a finishing treatment. Thus, artificial leather having an apparent density of 0.25 g / cm ³ and a nap length of about 1.3 mm was obtained.

The R value obtained from the deflection curve of this artificial leather measured in the same manner as in Example 1 was 37%, and the two reflections at around 90 degrees on the reflection curve as shown in FIG. It had a remarkable valley with a change in light quantity. As in the case of Example 1, the difference in color density in the naked eye judgment after sewing was large.

[0037]

According to the present invention, it is possible to provide a product in which the color difference on the surface due to the napped directions is reduced as much as possible, and it is possible to improve the sewing yield in the field of clothing and materials.

[Brief description of the drawings]

FIG. 1 is a model diagram of a method for measuring a deflection angle reflection curve according to the present invention.

FIG. 2 shows an example of a deflection angle reflection curve of a conventional artificial leather.

FIG. 3 shows an example of a bending reflection curve of the artificial leather of the present invention.

[Explanation of symbols]

 S: Sample surface i: Incident light R: Reflected light α: Incident angle γ: Light receiving angle N: Normal line of sample surface O: Center point a: Direction of nap R1: Reflected light amount at 0 degree R2: 0 degree to 180 Reflected light amount in the degree rotation category R3: reflected light amount at 180 degrees

Claims (3)

[Claims] 1. An artificial leather having a polymer elastic body provided to an entangled body made of ultrafine fibers and having a raised surface made of ultrafine fibers on at least one side, wherein the raised surface is 0 to 180 degrees by an automatic goniophotometer. An artificial leather characterized in that the R value obtained by the following equation from the bending reflection curve measured by rotation is 25% or less. R value (%) = (R1−R3) / (R1−R2) × 100 (where the amount of reflected light at R1: 0 degrees, R2: 0 degrees
Minimum reflected light amount in the 180-degree rotation category, R3: 180
Shows the amount of reflected light in degrees. ) 2. An artificial leather comprising a sheet in which an entangled body composed of ultrafine fibers is entangled and integrated with a woven or knitted fabric, a polymer elastic body is provided, and at least one surface thereof has a napped surface composed of ultrafine fibers. The artificial value characterized in that an R value obtained by the following equation according to claim 1 is 25% or less from a bending angle reflection curve measured by rotating the napped surface by 0 to 180 degrees with a bending angle photometer. leather. R value (%) = (R1−R3) / (R1−R2) × 100 (where the amount of reflected light at R1: 0 degrees, R2: 0 degrees
Minimum reflected light amount in the 180-degree rotation category, R3: 180
Shows the amount of reflected light in degrees. ) 3. The artificial leather according to claim 2, wherein at least a part of the constituent yarn of the woven or knitted fabric is made of a high twist yarn of 500 T / m or more and 4500 T / m or less.