JPH0726338B2 - High strength flexible leather - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-like material having high strength, low elongation, excellent abrasion resistance and flexibility.

[0002]

2. Description of the Related Art Conventionally, in the production of artificial leather, ultrafine fibers and polymer elastic bodies, which are advantageous for obtaining flexibility and mechanical performance similar to natural leather, have been mainly used. Various methods have been proposed.
However, it is the current situation that what satisfies both the texture and the mechanical performance like natural leather has not yet been realized. Here, the conventional general manufacturing methods are as follows.

That is, as a basic method for obtaining a flexible artificial leather, for example, a card, a cross-wrapper, a random webber, etc. are used by forming an ultrafine fiber generating composite fiber composed of two kinds of polymer components having different solubilities into a staple. Sheet into a sheet, entangle the fibers with each other by needle punching, etc., and add a polymer binder such as polyurethane,
Although a flexible artificial leather can be obtained by removing one component from the composite fiber, the thus obtained product has a drawback that the strength properties such as tensile strength and abrasion strength are poor. .

Therefore, in addition to the conventional softening technique, in order to improve the tensile properties such as tensile strength and abrasion strength of the artificial leather sheet, a high speed fluid is applied to the needle-punched nonwoven fabric of the ultrafine fiber generating composite fiber. There is also a method in which the composite fiber is divided and entangled in units of ultrafine fibers. However, the entanglement of the ultrafine fibers by this method is effective for the surface of the non-woven fabric, but is not effective for the inner layer of the non-woven fabric, and if it is attempted to entangle the ultra-fine fibers up to the inner layer portion. , High energy jetting fluid is needed. Therefore, not only the cost becomes high, but also the surface of the non-woven fabric has conspicuous irregularities due to the fluid ejection, and the obtained artificial leather has a low quality. In addition, it is impossible to reduce the elongation required for car seats, sports shoes, etc.

On the other hand, knitted and woven fabrics are sandwiched between them, and the length is 10
There is a method (Japanese Patent Publication No. 60-29775) of performing high-speed fluid treatment on a sheet made of sea-island structure fibers having a size of not more than mm.
However, although this method has a certain effect on the method of obtaining a high density and short napsuede, it has a drawback that the single fiber is very easy to come off and the abrasion strength is poor because the fiber length is extremely short. Further, as a known example, there is a method of needle-punching a knitted fabric between non-woven webs or on one side, but within the range of conventional examination, when a knitted fabric is used, a thread is caught in the barb of the needle needle, and knitted. Since the damage to the woven yarn is large, the strength reinforcing effect is small, and a sufficient expected effect cannot be obtained. Product fullness and appearance (especially in the case of nap formation)
In order to improve the quality, it is necessary to increase the degree of fiber entanglement, but if the number of needle punches is increased to increase the degree of entanglement, the strength of the knitted fabric will decrease, and both cannot be satisfied. It was Particularly, when the cut end of the knitted fabric is exposed on the surface, there is a drawback that the appearance is remarkably deteriorated.

Further, as a similar technique disclosed by punching, Japanese Patent Application Laid-Open No. 57-25482,
There is Japanese Patent Laid-Open No. 57-82583, but the technique proposed in them is exclusively used for the gap between the constituent fibers (the gap between the filaments of the multifilament yarn) in the multifilament yarn that composes the knitted fabric. The fiber is made to enter and entangled with the constituent filament units of the yarn, and it is intended to obtain high seam strength and tear strength. When using a needle punch for the confounding means under such a technical idea, it is of course necessary to use it under the condition that the barb of the needle needle acts on the individual constituent filaments, and then, immediately, The individual constituent filaments are damaged, and as described above, the constituent filament fibers are damaged, the yarn is damaged,
Further, there is a problem that the strength of the knitted fabric is reduced, and the cut end of the filament is exposed on the surface, resulting in a remarkable deterioration of the appearance quality. In order to prevent such damage to the filament, what is described in these publications as being actually carried out as a means for giving a entanglement is an entanglement by a high-pressure water flow. With regard to the punching entanglement treatment technology for the material containing the, the possibility of applying the treatment with a high-pressure water stream was exclusively investigated, and the entanglement imparting using a needle was generally not considered. In addition, rather, the basic technical idea in the inventions described in these publications, the fact that the interlacing is performed by allowing the ultrafine fibers to exclusively enter the inter-fiber gaps of the multifilament yarns that form the knitted fabric, Although it may be effective in improving the seam strength as aimed at by the invention, the fact that the fibers are entangled to the inner and deep layers of the constituent yarns of the knitted fabric, the problem of the feeling, particularly the poor flexibility There was also. That is, there was a problem of physical property imbalance that the flexibility was poor if the strength and elongation properties were emphasized.

[0007]

In the present invention, if softening, which is a drawback of conventional artificial leathers, is emphasized, the feeling of fullness becomes poor and it is difficult to retain strength and reduce elongation, while the physical properties of elongation are high. It aims to solve the problem of physical property imbalance, in which flexibility is inferior if the emphasis is placed on, and to provide a leather-like material that satisfies both flexibility and strength / elongation properties at the same time and has a sense of fulfillment.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors finally arrived at a highly strong and flexible leather-like material of the present invention.

That is, the leather-like material of the present invention uses ultrafine fibers having a denier of 0.8 or less and a raw fiber length of 20 mm or more, and a strong twist yarn having a twist number of 1250 T / m or more and 4000 T / m or less. The strong twist knitted woven fabric, wherein the structure of the strong twist knitted woven fabric is not substantially destroyed, and the ultrafine fibers are substantially entangled with the single fibers constituting the strong twisted yarn. It is a high-strength, flexible leather-like material which is tightly entangled with the weaving structure of the twisted knitted fabric so that it is inseparable and integral, and whose shape is retained by a polymer binder.

[0010]

The present invention will be described in detail below.

As an example of one specific means for achieving the present invention, first, an ultrafine fiber having a denier of 0.8 or less or an ultrafine fiber web is formed. The web, the strongly twisted knitted fabric or the strongly twisted fabric (hereinafter abbreviated as knitted fabric) and this web are overlapped and needle punched to sufficiently enhance the entanglement of the web itself and the entanglement of the web and the knitted fabric. Forming a detached integral structure. After that, after the latent torque removing step of the strongly twisted knitted fabric is carried out, if necessary, a combined treatment of a binder applying step and an ultrafine fiberizing step is performed.

The non-separable integral structure as used herein means, for example, that ultrafine fibers are not only entangled at random in the structure of knitted fabrics but also entwined with each other while maintaining their morphology, which causes a considerable stress. The knitted woven fabric and the non-woven fabric web do not separate even after peeling, and a structure having a strong entanglement that causes tissue destruction of a leather-like object rather than peeling when the stress becomes stronger. This structure has a great effect on the improvement of the custom wear and the strength / elongation property which will be described later.

However, in the present invention, the strongly twisted yarn constituting the strongly twisted knitted fabric has a twist number of 1250 T / m or more and 4000 T / m or more.
Since the following strong twists are given, the yarn has a strong force for maintaining a rod-like structure with strong integrity, and the constituent monofilaments do not get caught on the barb of the needle. The structure of (1) is not substantially destroyed, and the ultrafine fibers are substantially not entangled with the single fibers constituting the strong twist yarn, so that the ultrafine fibers become inseparable and integral with the weave structure of the strong twist knitted fabric. A strongly entangled structure is obtained.

The polymer of the ultrafine fibers forming the nonwoven web of the present invention is not particularly limited, but is a polyester system such as polyethylene terephthalate (hereinafter referred to as PET), polybutylene terephthalate (hereinafter referred to as PBT), and polyester elastomer. , Nylon 6, nylon 6
6. Polymers having a fiber-forming ability, such as polyamide type such as polyamide elastomer, polyurethane type, polyolefin type, acrylonitrile type, etc. are preferable. Among these, P
ET, PBT, nylon 6, nylon 66 and the like are particularly desirable from the viewpoint of the texture of the processed product and the practical performance. Also,
Examples of sea-island type fibers that can be made into ultrafine fibers by removing some of the polymers that make up the conjugate fiber or by peeling them off from each other include, for example, polystyrene and its copolymers, PVA, and copolymers as the components to be removed. One or two kinds of polyester, copolyamide, etc. can be used.

The thickness of the ultrafine fibers used in the present invention is preferably 0.8 denier or less in order to enhance the performance as a leather-like material, that is, the flexibility, the feel, the appearance quality and the tenacity properties. Such ultrafine fibers are obtained from the following composite fibers. For example, a polymer array fiber composed of two or more kinds of polymers (Japanese Patent Publication No. 44-18369) and an easily splittable conjugate fiber in which two kinds of polymers having low compatibility are adjacent to each other (Japanese Patent Publication No. 53-37456). Issue bulletin). However, the present invention is not limited to this, and fibers of an advanced form can be applied based on the idea.

Further, the raw material fiber of the ultrafine fiber to be subjected to the needle punching, whether it is a composite fiber before being ultrafine or after being ultrafine, has a raw fiber length of 20 mm or more. Is essential. The fiber length is 2
This is because effective entanglement cannot be achieved unless the distance is about 0 mm or more. However, after post-processing such as slicing and buffing of the fabric, the final product may contain fibers that have been cut to less than 20 mm, which is an effective entanglement. Since it is a short fiber generated after the above-mentioned achievement, even if it is present in the fabric, there is no particular inconvenience and it does not matter.

As the polymer elastic material used in the present invention, any polymer having rubber-like elasticity such as polyurethane, SBR, NBR, polyamino acid, acrylic adhesive and the like can be used. As the binding method, various methods such as a method of coating or impregnating a polymer elastic body solution and then solidifying it, or a method of coating or impregnating them with an emulsion or latex thereof and drying and fixing them can be used.

The twist number of the yarn constituting the knitted fabric intervening in the middle layer or the surface layer of the leather-like material of the present invention is 1000T.
/ M or more, and most preferably 1500 T / m or more. If the twist number is less than 1000 T / m, the tightness of the single yarns (single fibers) that make up the yarns is insufficient, so during needle punching, the barb of the needle is caught by the yarns or the single yarns (single fibers). , Single fibers are cut or damaged. Therefore, the structure of the knitted fabric is destroyed, the strength of the knitted fabric is significantly reduced with an increase in the number of punches, the strength of the fabric structure is significantly reduced as a whole, and as a result, it is difficult to contribute to the low elongation. The intended purpose of the present invention cannot be achieved. Further, when the knitted fabric is broken, the nonwoven web and the broken yarn or single yarn (single fiber) of the broken knitted fabric are entangled with each other, and the anchor effect reduces the degree of freedom, resulting in a hard fabric structure as a whole. Therefore, the broken ends of the fibers constituting the knitted fabric are exposed on the surface, and the touch appearance is significantly impaired. Further, if the number of twists is too large, the fibers become too hard, which is not preferable from the viewpoint of softening the texture and entanglement. Therefore, it is preferably 4000 T / m or less.

The type of the strongly twisted yarn used is not particularly limited, such as filament yarn, spun yarn, innovative spun yarn, filament yarn / spun yarn.

The basis weight of the strongly twisted knitted fabric is 20 to 200 g / m.
The range of ² is desirable, and most preferably 30 to 1
It is in the range of 50 g / m ² . If the basis weight is less than 20 g / m ² , the form of the knitted fabric becomes extremely loose, and wrinkles occur when sandwiched in the middle layer part or when superposed on the surface, and it becomes difficult to uniformly spread. Further, when the fabric weight exceeds 200 g / m ² , the knitted fabric structure becomes dense,
Insufficient penetration of the non-woven web prevents the non-woven web from becoming highly entangled, which makes it difficult to form a non-separated and integrated structure. Regarding the types of strongly twisted knitted fabrics, weft knitting represented by warp knitting, tricot knitting, lace knitting and various knitting based on their knitting methods, or plain weave, twill weaving, satin weaving and their weaving methods are basically used. The various kinds of fabrics are not particularly limited. Among these woven fabrics, preferred are those in which the strong twisted yarn is used at least in the warp and the weft, and particularly preferable are those in which the strong twisted yarn is used. When the warp yarn is used on one side of the warp, the fiber damage is greatly suppressed by planting and punching the needle so that the barb of the needle faces the strongly twisted yarn. Furthermore, as the weft, SZ twist 1-1, 2-
It is preferable that alternate charging such as 2, 4-4, or S (or Z) single twist yarn driving is made. In the case of using those in which the driving state is changed, the latent torque unwinding treatment after the needle punching can be used to obtain a natural grain-like or Yangyanagi-like appearance by utilizing the torque restoring force of the strongly twisted yarn. This is possible by skillfully utilizing the usual strong twist fabric treatment (rubbing in hot water), but simply adding the latent torque unwinding treatment of the strong twist yarn by hot water or dry heat treatment Flexibility is often greatly improved. As another case, needle-punching a woven fabric that has been subjected to torque development in advance may substantially increase the elongation of the woven fabric and have a reinforcing effect (reducing the breakage of the woven fiber). Which one is selected may be appropriately determined depending on the purpose.

The use of yarns for knitted fabric can be appropriately changed according to the purpose, but one yardstick is from 30 denier to 300 denier. A finer thread is better in terms of uniformity, but if it is too thin, it will be caught tightly with the barb and will be easily damaged. On the other hand, if the needle is too thick, it will not escape when the tip of the needle hits the thread, and the fiber is likely to break, which is not preferable. The most preferable range of the balance between the effect of integrating the fibers as a strongly twisted yarn and the thickness is 50 denier to 150 denier. In the present invention, by using a strong twist yarn, the fiber is less likely to be caught in the barb,
It is easy to come off even if it gets caught. For this reason, a damage reduction effect which has not been expected in the past occurs, and the intended effect of the present invention can be obtained. Therefore, the needle resistance is small,
The impact and load applied to the punching machine are small and high density knitted fabrics can be used. For example, in the case of knitting, there is no problem with 40 gauge, 45 gauge, etc.
It is also possible that the weft density is 120 or more, and in some cases, 300 or more.

On the contrary, by using such a high-density woven fabric, it is often preferred that high entanglement and high strength can be achieved. It can be said that the present invention is truly epoch-making because it overcomes the limit of the use of such a high-density fabric, which has hitherto been the limit.

The fibers constituting the knitted fabric are polyester,
Any fiber that can be woven or woven such as synthetic fibers such as polyamide and aramid, natural fibers such as cotton, wool and silk, regenerated fibers such as rayon, and semisynthetic fibers such as acetate can be used.

The weight ratio of the knitted fabric to the nonwoven web is 7
It is preferably 0% or less, and most preferably 10 to 5
It is 0%. When the weight ratio of the knitted fabric to the nonwoven web exceeds 70%, the knitted fabric is likely to be exposed on the surface of the nonwoven fabric.

For intertwining the non-woven web and the strong twist knitted woven fabric, a strong twist knitted woven fabric is formed between a short fiber non-woven web or a long fiber non woven web formed into a sheet by using a card, a cross wrapper, a random web or the like. Is preferably laminated and the fibers are entwined with each other by needle punching, but only one side may be used. In selecting the needle used for the needle punch, there is a point that cannot be generally stated in relation to the knitted fabric, but as a guideline, the barb throat depth is 30 to 150 μ,
It is preferably 50-100 μm. Further, particularly when it is desired to avoid damage to the knitted fabric by needle punching, a remarkable effect can be obtained by orienting the barb of the needle obliquely, for example, at 45 ° so as not to hit the knitted fabric at a right angle. In such a case, it is administratively advantageous to use a needle having a barb oriented in one direction. The most preferred example of this is a needle with only one barb. However, without being limited to this, the object of the present invention can be sufficiently achieved even by using an ordinary needle.

There are various methods for removing sea components, such as a solvent extraction method and a thermal decomposition method, in the case of removing sea components with ultrafine type fibers. Generally, the solvent extraction method is simple. Is. This operation is performed before or after applying the elastic polymer. Buffing is generally performed using sandpaper.

Particularly, according to the present invention, good naps can be obtained by buffing the surface after applying the binder. In such a case, the abrasion resistance is extremely strong due to the strong entanglement of the ultrafine fibers and the knitted fabric by needle punching, and it is not easy to remove the naps.

[0028]

According to the present invention, the following effects can be obtained. Since there is no damage to the knitted fabric by the needle, it has a non-separable integral structure in which the ultrafine fiber web and the strongly twisted knitted fabric are tightly entangled, and it has a high strength, low elongation, and excellent wear characteristics that have never been obtained before. A high-quality leather-like material is obtained.

This is very flexible, even compared with the one obtained by entangling the ultrafine fibers in the inter-fiber gaps in the constituent yarns of the knitted woven fabric by punching with a high-pressure water stream, which is one of the conventional techniques. In addition, it is of high commercial value, with high quality and sufficient separation and integrated structure.

[0030]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. The physical properties were measured by the following methods. Flexibility: Method A of JIS-L1079, 5.17 Tensile strength and elongation: 5.12.1 of JIS-L1079: Custom wear: Measurement conditions Air pressure: 0.281 kg / cm ² Pressing load: 0.454 kg Friction speed ( Reciprocation / min): 125 ± 5 times Rotation of test piece: 1/100 reciprocation (48 seconds) Reciprocation distance: 2.54 cm Paper: # 400-RIKEN Example 1 Polyethylene terephthalate as island component and polystyrene as sea component 80/20 composition ratio, 16 islands,
Composite fiber denier 3d, fiber length 51mm, crimp number 14
Cards made from raw cotton of mountain / inch sea-island type composite fiber,
A web was prepared through a cross-wrapping process, and then 100 sheets / cm ² was needle-punched with a pre-punch to prepare two felts. 750-36 in the middle
f, a plain woven fabric (weight per unit area of 90 g / m ² ) using raw twisted yarn with a twist of 2000 T / m was uniformly spread and inserted.

The sheet thus obtained is a three-layer sheet in which a sea-island fiber sheet, a strongly twisted woven fabric, and a sea-island fiber sheet are superposed, and the basis weights are 180 g / m ² and 80 g / m ² , respectively.
It was m ² and 90 g / m ² . Next, using a needle board in which this three-layer sheet was randomly implanted in the direction of a needle depth of 7 mm barb, needle punching of 2500 needles / cm ² was performed to obtain a nonwoven fabric having a basis weight of 380 g / m ² . The strong-twisted fabric used had no damage due to barbs and no catching, and the nonwoven web and the strongly-twisted fabric had a non-separable integral structure. This non-woven fabric was subjected to latent torque unwinding treatment with hot water at 98 ° C., a PVA solution was applied to the island component in a solid content of 35% and dried, and then polyurethane was coagulated in water. This sheet is further dipped in hot water and repeatedly squeezed to produce PVA and D
The MF was removed. This sheet is subjected to a buffing machine to form naps, and then jet dyeing is performed with a disperse dye at 120 ° C. for 60 minutes to give a suede tone having a thickness of 1.18 mm, a basis weight of 446 g / m ² , and a density of 0.378 g / cm ² . I got artificial leather.

The obtained leather-like product had a structure in which the ultrafine fibers and the strongly twisted woven fabric were inseparable and integrated, was flexible, and was rich in fullness. Moreover, as shown in Table 1, it was excellent in strength and wear characteristics and had a low elongation, and was suitable for non-clothing fields such as car seats, sports shoes and furniture.

[0033]

[Table 1]

Comparative Example 1 Instead of the strongly twisted fabric laminated between the pre-punched up felts of Example 1, a polyester fiber taffeta of 75D-36f, 300 T / m was inserted, and the subsequent processings were all performed in Example 1.
It carried out similarly to. The obtained leather-like material had a large damage to the fabric due to barbs during needle punching, and it was difficult to lower the elongation as well as the strength, and the fabric was mixed on the surface, resulting in a poor quality appearance. Further, the broken fabric was entangled with the non-woven web, which gave an anchor effect and a hard texture.

Comparative Example 2 Needle punching was carried out without inserting the knitted fabric into the composite fiber sheet of Example 1, and the subsequent processing was carried out in the same manner as in Example 1. The obtained leather-like material was inferior in strength properties and abrasion properties, and it was impossible to reduce the elongation, which was fatal in the non-clothing field.

Claims (3)

[Claims] 1. An ultrafine fiber having a denier of 0.8 or less and a raw fiber length of 20 mm or more, and a strongly twisted knitted fabric using a strongly twisted yarn having a twist number of 1250 T / m or more and 4000 T / m or less, The structure of the strongly twisted knitted fabric is substantially not destroyed, and the ultrafine fibers are substantially not entangled with the single fibers constituting the strongly twisted yarn. A high-strength, flexible leather-like material that is strongly entangled with the knitting and weaving structure so that it is inseparable and integral, and that its shape is retained by a polymer binder. 2. The high-strength, flexible leather-like material according to claim 1, wherein the strongly twisted woven fabric is composed of both the warp yarn and the weft yarn. 3. The high-strength, flexible leather-like material according to claim 1, wherein the leather-like material has a light texture pattern.