JPS5813661B2 - Method for manufacturing non-woven fabric structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a nonwoven fabric structure.

More specifically, the present invention relates to a method for producing a nonwoven fabric structure in which ultrafine single fibers and fiber bundles formed from the single fibers are three-dimensionally intertwined with a relatively coarse knitted fabric.

An object of the present invention is to provide a high-quality nonwoven fabric structure that is flexible and strong, has a density close to that of natural leather, and has a texture that closely resembles that of natural leather.

A further object of the present invention is to provide a nonwoven fabric structure that is suitable for use in silver suede, that is, nubuck-like artificial leather, which has not been found in conventional artificial leather.

It is generally known that deerskin-like artificial leather can be obtained by filling the fiber gaps of a nonwoven fabric made of ultrafine fiber bundles with a rubbery elastic polymer.

However, the density of the nonwoven fabric in the artificial leather obtained in this manner is low, and in order to increase the density and give a sense of fullness, it is necessary to increase the filling amount of the rubber-like elastic polymer.

The resulting artificial leather becomes rubber-like.

In addition, when used for clothing, the thickness of artificial leather should be 1 m.
It is preferable that the thickness be less than m, and if it is thicker than this, flexibility (drapeability) will be lost and it will be unsuitable for use in clothing.

However, in the case of nonwoven fabrics consisting only of ultrafine fiber bundles,
The thinner the material, the weaker the strength, and it is extremely prone to tearing, especially at seams and other areas that are subject to strong bending.Also, when the surface is brushed, the fluff becomes fluff on the fiber bundles, and the condition of the nap is significantly rougher than that of natural leather. Become something.

As a result of intensive research aimed at improving the above-mentioned points, the present inventors have finally accomplished the present invention.

The present invention provides a short fiber nonwoven structure in which short fibers in the form of fiber bundles of various sizes and thicknesses and single fibers subdivided from the bundles are mixed and intertwined three-dimensionally. The present invention relates to a method for manufacturing a nonwoven fabric structure in which a knitted fabric or woven fabric is inseparably embedded in the inner layer region of the nonwoven fabric by entwining the fibers constituting the nonwoven structure.

This structure is extremely suitable for producing a leather-like material by impregnating it with a rubber-like elastic polymer, and furthermore, for manufacturing a nubuck-like artificial leather by raising the surface of the leather-like material.

The product obtained by the method of the present invention is characterized by a short fiber nonwoven structure in which ultrafine single fibers and fiber bundles of various sizes, which are aggregates of the single fibers, are intertwined three-dimensionally. The inner layer is filled with a knitted fabric or woven fabric (hereinafter simply referred to as a knitted fabric) to form an integral structure, thereby making it possible to obtain a leather-like product with a substantial feel and high strength.

In other words, the fiber structure of the present invention has a structure in which an ultrafine fiber bundle and an ultrafine single fiber are intertwined, and are also intertwined with the intervening knitted fabric to form an inseparable composite structure, unlike conventional single fibers or fiber bundles. It is possible to provide a leather-like material with physical properties that cannot be achieved with a nonwoven fabric made entirely of the same material.

In other words, the texture and strength of a nonwoven fabric, such as its density and flexibility, are closely related to the density of the nonwoven fabric, and mere intertwining of fiber bundles is not sufficient to obtain desirable strength and texture.

Not only the intertwining of fiber bundles, but also the intertwining of ultra-fine single fibers, the intertwining of fiber bundles and single fibers, and even the intertwining of knitted fabrics interposed inside, etc.
A nonwoven fabric with extremely high density is obtained.

The non-woven fabric structure of the present invention has such a very high-order entangled state, and as a result, it has a density comparable to that of natural leather (approximately 0.2 For the first time, a leather-like material with a strength of 4 g/cm2) was obtained.

Specifically speaking, sewing strength and dimensional stability are physical properties that naturally pose problems for clothing products, but these values are related to the structure of the nonwoven fabric, that is, the state of intertwined bonding between the fibers that make up the nonwoven fabric. This can be said to be related to the difficulty in slipping through the fibers.

The difficulty of this fiber slipping through naturally depends on the tightness of the nonwoven fabric.
In other words, it is greatly affected by density.

Therefore, it is generally known that increasing the density of the nonwoven fabric is the most appropriate way to improve the strength and dimensional stability of the nonwoven fabric.

As mentioned above, the fiber structure of the present invention includes not only fiber bundles, but also single fibers subdivided from fiber bundles, fibers of knitted fabrics interposed inside, etc., integrated in an extremely complex intertwined state. Naturally, its density is much higher than that of conventional nonwoven fabrics made of only fiber bundles, and as a result, its strength and dimensional stability are extremely excellent.

In addition, regarding flexibility, since the fiber bundles are considerably finely divided into ultra-fine single fibers, they are more flexible than nonwoven fabrics made only of fiber bundles.

On the other hand, the coexistence of fiber bundles and single fibers of various sizes has a great influence on the fluff of the surface.

In other words, when the surface of the nonwoven fabric structure is brushed,
Thin single fiber fluffs are tightly packed between the fluffs of fiber bundles of various sizes and thicknesses, creating a smooth surface with an extremely high surface fluff density.

In particular, the leather-like material obtained by the method of the present invention has noticeable fuzziness of finely divided fiber bundles and single fibers, has a fine surface texture, and has a suede-like appearance (natural leather with a brushed surface on the flesh side). Rather, it is a nubuck-like artificial leather with a brushed silver side.

As shown in the motel structure of the natural leather shown in FIG. 4, the thickness of the constituent fibers and fiber bundles becomes thinner as they approach the grain side from a thick fiber bundle consisting of thick fibers on the flesh side.

Therefore, compared to suede leather, which has a rough texture with the flesh side raised and fluffed with thick fiber bundles, nubuck leather has a fine texture with the silver side raised and fluffed with thin fiber bundles.

The nonwoven fabric structure obtained by the method of the present invention has a downy surface covered with fluff from finely divided fiber bundles of various thickness and fluff of single fibers, as shown in Fig. 1. There is.

It has a generally velvet-like surface and is an extremely valuable non-woven fabric structure.

In the method of the present invention, the knitted fabric interposed in the intermediate layer of the short fiber nonwoven structure plays an important role in effectively entangling the short fibers and stably forming a dense and dense nonwoven structure with the short fibers. is fulfilled.

This presence can further improve the density of the fiber fabric structure and at the same time give a sense of fullness to the nonwoven fabric.

Furthermore, it also contributes to increased strength and dimensional stability.

This is because the knitted fabric is inside, so during the interlacing process of making it into a non-woven fabric, the fiber bundles and single fiber short fibers in the structure of the knitted fabric insert, penetrate, or become entangled, creating a strong three-dimensional intertwined structure. This is to become.

In other words, in order to make short fibers into non-woven fabrics, conventionally the fibers were crimped or adhesive was used to fix the fibers to a certain degree, and then, based on this bonding force, new materials were created using needle punching, etc. This creates a strong bond.

Since fibers are to be entangled, if the fibers are not free, they cannot move in random directions and become entangled.

However, if there is too much freedom, strong confounding connections will never occur.

Therefore, when the entanglement process begins, one end of the short fibers is supported and fixed by something, and the free end or freely movable part of the short fiber becomes the freely movable part of the other fiber. A desirable mechanism for forming a nonwoven fabric is to intertwine the materials and form a three-dimensional entangled body through the intertwining occurring one after another in a chain manner.

The knitted fabric interposed inside the nonwoven fabric of the present invention acts like a support for the short fibers when they begin to intertwine, and prevents the fibers from slipping out.

Since the fibers do not slip out, as the intertwining progresses, the three-dimensional intertwining of the nonwoven fabric becomes denser, and the density of the nonwoven fabric increases.
A non-woven fabric structure with strength and fullness is obtained.

Furthermore, the intervening knitted fabric is vertically oriented (
It plays a major role in facilitating the presence of fibers (in the direction perpendicular to the sheet plane).

This is because the knitted fabric is interposed inside, so the fiber bundles and single fibers inevitably penetrate or insert into the structure of the knitted fabric when entangled.

The fibers that penetrate or insert into this knitted fabric are
It remains as fiber bundles or single fibers oriented in the vertical direction, improving the compression ratio and compression recovery rate of the nonwoven fabric.

As mentioned above, knitted fabrics not only provide the strength of the knitted fabric itself to non-woven fabrics, but also assist in the three-dimensional entanglement of the fiber bundles and single fibers that make up the non-woven fabric, and furthermore, they help in the three-dimensional entanglement of the fiber bundles and single fibers that make up the non-woven fabrics. It facilitates the presence of fibers and serves to significantly improve the physical properties of the nonwoven fabric of the present invention.

The expression "entanglement" refers to the fact that ultrafine fiber bundles and single fibers enter the voids of the knitted fabric, and the constituent fibers of the knitted fabric become intertwined with the ultrafine fiber bundles and single fibers, making it easy for these fibers to slip through. It shows how intertwined they are.

In other words, the constituent fibers of knitted fabrics are also one of the elements that make up the three-dimensional entangled body, and although they are different types within the entangled body made up of fiber bundles and single fibers, it is expressed that they are not heterogeneous. In the nonwoven fabric structure of the present invention, separation between the knitted fabric and the nonwoven intertwined body, which occurs in other three-layer structures, does not occur.

The products obtained by the method of the present invention will be specifically illustrated and explained in detail below.

The nonwoven fabric structure of the present invention has a cross-sectional structure as shown in FIGS. 1A and 1B.

A is a diagram in which there are relatively many bundles and relatively few mouths.

(The cross section shown in FIG. 1 is a view after the surface has been subjected to a napping process, but the cross-sectional structure before the napping process is also essentially the same.

The same can be said of FIGS. 2, 3, and 4.

) In Figure 1, a is a cross-sectional view of the knitting structure of the knitted fabric, and b is a cross-sectional view of the knitting structure of the knitted fabric.
is an ultrafine fiber bundle, b' is a finely divided fiber bundle, and c is an ultrafine single fiber.

d represents the fuzz of the fiber bundle, d' is the fuzz of the subdivided fiber bundle, and e is the fuzz of the single fiber.

From the figure, b, b', and c are equivalent in terms of fiber entanglement,
It can be seen that the fiber bundles are intertwined as if they were one thick fiber, and the fiber bundles are intertwined, the fiber bundles and single fibers, and the single fibers are intertwined, and the knitted fabric a is embedded in the inner layer area. .

The important point is that the ultrafine single fibers C exist as a single entangled unit, which is clearly different from the non-woven fabric structure outside the present invention, which consists only of intertwined fiber bundles b and b' as shown in Fig. 3. There is.

The fuzz d, d', and e are generated from b, b', and c near the surface by the napping process, respectively.

Figure 2 shows a three-layer structure sheet product other than the present invention, in which there are sheets each having a nonwoven fabric structure on the top and bottom, and a knitted fabric is interposed in the middle layer without interference with the nonwoven fabric, and the knitted fabric a is not embedded. .

If you compare this with FIG. 1, you will understand that the knitted fabric a is embedded in the nonwoven fabric structure.

Next, the method of the present invention will be explained.

Ultrafine fibers with a single fiber fineness of 0.5 denier or less can be produced, for example, by ordinary melt spinning methods, flash spinning methods, ultrafine fibers by super draw method of polyethylene terephthalate, falling tension spinning of cugra ammonium fibers, or by using acrylic fibers. Wet high draft spinning, or
It can be produced by known techniques such as a method of dissolving and removing sea components from so-called sea-island fibers using a condensation spinning method or a blend spinning method.

In the method of the present invention, these ultrafine fibers are bundled and cut to form short fiber bundles.

Ultrafine fibers can be bundled using adhesives or oils, or in the case of thermoplastic fibers, by self-adhering by heat treatment of the bundle, or in the case of wet-spun fibers, by treating them with a bundle guide during the coagulation process to make them self-adhesive. will also be done.

In this case, the degree of convergence is important, and for the purposes of the present invention, at least some of the bundled yarns are made into ultra-fine single fibers during the sheet-forming process described below or during the three-dimensional entangling process using high-pressure water jets. It is necessary to be in a converged state to the extent that it can be defibrated into fibers again.

This defibration property can be arbitrarily controlled depending on the target final product.

That is, as detailed above, the characteristics of the product change depending on the mixing ratio of single fibers and bundled fibers.

If the monofilament component is the main component, a fine-textured nubuck-like product can be obtained, but in this case, the binding must be weak, and binding with an oil agent or a very small amount of glue is preferable.

The bundled short fibers are then formed into a sheet.

Forming into sheets is performed by a papermaking method.

When short fiber bundles with weak binding power are used, it may be difficult to form them into a sheet, so it is preferable to form them into a sheet by a papermaking method.

The paper-making method is particularly preferable also when defibrating the bundled yarn in the sheet-forming process.

Defibration proceeds by stirring the prepared slurry in a slurry tank.

Next, the above sheet is laminated with a knitted fabric to form a laminate.

Preferably, it is a three-layer sheet in which a knitted fabric is sandwiched between the above-mentioned sheets as an intermediate layer.

In this case, the product obtained has a leather-like appearance on both the front and back sides.

When a sheet is manufactured by a papermaking method, lamination can be carried out simultaneously with papermaking.

For this purpose, a hydroformer type two-layer paper making machine can be suitably used.

This laminate is then subjected to an interlacing treatment.

The entanglement process is performed by a high-pressure water stream jetted from a fine-hole nozzle.

Conditions such as the nozzle hole diameter and the jetting pressure of the water stream may be appropriately set experimentally depending on the focusing force of the short fiber bundle, the type of knitted fabric, and the desired degree of entanglement.

The preferred nozzle hole diameter is 0.05-0. It is 3 mm.

The ejection pressure of the water stream is preferably 5 to 70 kg/cm2.

The shape of the water flow is arbitrary, and a sprinkle flow, a columnar flow, a fan flow, etc. are used.

Due to the impact of the water flow, the short fibers within the sheet move, unravel, and become entangled.

In the present invention, short fiber bundles are defibrated by mechanical force in the sheeting process and/or high-pressure water treatment, and ultra-fine single fibers and finely divided fiber bundles of various sizes are entangled. I can get a body.

Next, the method of the present invention will be explained by showing one specific example.

When spinning short fibers of fiber bundles, for example, multifilaments of copper ammonia rayon fibers, single fibers of 0.5 denier or less are collected by a focusing guide before they are completely solidified, and the single fibers self-adhere to each other. 10 fiber bundles
The short fibers of the fiber bundle are obtained by cutting into pieces less than mm.

The short fibers of the ultra-fine self-adhesive fiber bundles with a single yarn denier of 0.5 denier or less obtained in this way are made into a paper sheet using a hydroformer type paper machine, and then a relatively coarse knitted fabric is made. This is placed on top, and a separately made paper sheet is then placed on top of that to obtain a three-layer laminated sheet product as shown in FIG.

This laminated sheet material is subjected to a high-speed fluid flow (a water jet ejected at high pressure from a thin nozzle) to obtain a nonwoven fabric-like material having a three-dimensional entangled structure.

A considerable portion of the self-adhesive part of this nonwoven fabric has been peeled off, and it has been separated into thin fiber bundles and even single fibers, which are intertwined with each other, and also form a three-dimensional structure with the knitted fabric sandwiched between them. They are intertwined, resulting in the structure shown in Figure 1.

In the method of the present invention, the denier of the single fibers constituting the fiber bundle must be 0.5 denier or less; if it becomes thicker than 0.5 denier, the soft, moist, leather-like feel will be lost.

Furthermore, the fuzz that stands up when the surface is brushed becomes stiff, making it impossible to obtain a leather-like material with a good texture.

The thickness of the fiber bundle used is about 1 to 200 deniers, but the preferable range for use in clothing is about 2 to 60 deniers.

However, even if a somewhat thick denier fiber bundle is used, it is advisable to vigorously subdivide the fiber bundle when forming it into a non-woven fabric.

In any case, the nonwoven fabric structure of the present invention is mainly composed of fiber bundles of various sizes and thicknesses, that is, fiber bundles with various numbers of bundled single fibers, and single fibers in which the fiber bundles are subdivided. It was formed by

As the polymer forming the ultrafine fibers used in the present invention, any organic polymer substance having fiber-forming ability can be used.

For example, any of cellulose, cellulose acetate, polyamide, polyester, polyacrylonitrile, polyethylene, polypropylene, or copolymers thereof can be used.

On the other hand, the knitted fabric or woven fabric interposed in the middle layer in the cross section of the structure of the present invention needs to have a roughness that allows the ultrafine fiber bundles or ultrafine single fibers to penetrate or fill the knitted fabric in an entangled state, and has a basis weight. The amount is 10 to 100 g/m2 to 70 g/m2.

If it is less than 10 g/m2, the knitted fabric will become extremely loose, and when it is inserted into the middle part, it will not be spread out evenly and it will wrinkle.

Furthermore, it is so thin that fiber bundles and single fibers cannot be separated in the vertical direction, making it impossible to improve the fullness of the nonwoven fabric.

In other words, the value as a knitted fabric embedded in a nonwoven fabric structure is no longer recognized.

On the other hand, when the basis weight is 100 g/m2 or more, the textile structure becomes dense, the penetration and filling of fiber bundles and single fibers do not occur, and the nonwoven fabric layer fibers cannot be entwined with the fibers of the knitted fabric.
There is a tendency to not be able to create an integrated structure.

The fiber bundles and single fibers as shown in FIG. 2 are not intertwined, resulting in only a sheet-like product having a three-layer structure, which results in a leather-like product that lacks a sense of fullness and has low strength.

From the standpoint of flexibility, it is better to select the constituent fibers of the knitted fabric from multifilament yarns that do not exceed 70 d.

Regarding the types of knitted fabrics, there are various types of knitted fabrics such as warp knitting, typified by weft knitting and tricot knitting, lace knitting, and various knitted fabrics based on these weaving methods, as well as plain weaving, twill weaving, satin weaving, and various knitting fabrics based on these weaving methods. However, any type of fabric can be used as long as it has a weave structure that has surface stitches and textures that allow fiber bundles and single fibers to end up in the tissue, and also has voids inside. Alternatively, any fabric may be used as long as it has the same function.

The fibers constituting the knitted fabric may be any fibers that can be knitted and woven, such as synthetic fibers such as polyester and polyamide, and recycled cellulose fibers such as rayon and Cugra, but it is preferable that the single yarn denier is 3 deniers or less if possible. .

This is because knitted fabrics with too thick single yarn denier may make the leather-like material hard.

The fiber structure obtained by the method of the present invention is a fabric structure obtained by intertwining and finalizing fiber bundles of ultrafine fibers, single fibers, and knitted fabrics, but the fabric weight of the knitted fabrics is 4% of the fabric weight of the entire structure.
Preferably, it does not exceed 0% by weight.

If it exceeds 40% by weight, the knitted fabric tends to be exposed on the surface of the nonwoven fabric, and the elasticity unique to the nonwoven layer tends to be lost.

In the present invention, if the mixing rate of single fibers in the single fibers and fiber bundles is lower than 5% by weight, the nonwoven fabric will consist almost entirely of fiber bundles, and the above-mentioned drawbacks will appear.

On the other hand, if the monofilament content exceeds 95% by weight, the nonwoven fabric will be made mostly of monofilaments and will lose its leather-like feel, becoming paper-like.

As a guideline, the proportions of the fiber bundle and the finely divided single fibers are preferably 20 to 60% by weight, respectively.

When the fibers constituting the nonwoven structure of the present invention are inspected by pulling out the fibers, there are single fibers and bundles of various thickness and thickness.
It is thought that this mixing mode forms a stable and dense nonwoven structure using short fibers.

Determining the mixing ratio of fiber bundles and single fibers is difficult and currently requires visual judgment from enlarged photographs.

For example, a cross section of an arbitrary part of a nonwoven material is photographed at a magnification of 700 times using a scanning electron microscope.

Draw lines on this photo at equal intervals of 2 mm in length and width, and color the area occupied by the cross section of the single fiber in red.

Also, the portion occupied by the cross section of the bundle is colored blue.

After coloring, the photograph is cut into 2 mm square pieces along the ruled lines and separated into red colored pieces and blue colored pieces.

Next, by measuring the weights of these two types of small pieces, the ratio between the weight of the fiber bundle and the weight of the single fiber is determined.

This value is converted into a percentage to determine the mixed ratio of fiber bundles and single fibers.

The number of samples is n=20, and the average value can indicate the mixing ratio of fiber bundles and single fibers in the nonwoven fabric.

The method of the present invention and the structure and state of internal entanglement of the nonwoven fabric structure obtained thereby have been explained above.
A three-dimensional intertwined fiber structure in which ultrafine fiber bundles and single fibers of various sizes and thicknesses are three-dimensionally intertwined and integrated with knitted fabrics has a soft texture and strength similar to leather even as it is. It has the appearance of a leather-like product.

When this surface is brushed, a fluffy mixture of downy fiber bundles and single fibers is produced, resulting in a leather-like material having a nubuck-like surface.

Furthermore, by impregnating a nonwoven fabric structure with a rubber-like elastic polymer and interposing the elastic polymer between the fibers,
It is possible to make a better leather-like product.

That is, the objective can also be achieved by impregnating a rubber-like elastic polymer such as polyurethane or NBR into the gaps between the fibers of the fabric structure, which is an integrally entangled structure of the fiber bundle, single fibers, and knitted fabric of the present invention. Artificial leather is obtained.

That is, the voids in the fibrous structure of the nonwoven fabric structure are filled with a rubber-like elastic polymer, and the entire fibrous material is bound.

Next, when the surface of this sheet is brushed with sandpaper or a wire brush, a mixture of fluff from ultra-fine fiber bundles of various sizes and thickness and ultra-fine single fibers is raised.
Nubuck-like artificial leather is obtained by brushing the silver side of natural leather.

This artificial leather has a cross-sectional structure in which the fiber gaps shown in FIG. 1 are filled with small amounts of polyurethane dispersed, and is a completely new structure.

As mentioned above, the condition of the fluff covering the surface is an important requirement that influences the value as artificial leather.

In other words, the softer and finer the fluff, and the higher the fluff density, the higher the quality of natural leather, especially grain suede leather (
It can be an artificial leather with a feel similar to nubuck.

The downy fuzz of this artificial leather is not only a fiber bundle, but also
Ultra-fine single fibers are fiber bundles (the fiber bundles are also subdivided into various sizes and thicknesses, and many are subdivided into quite thin fiber bundles.

), and the density of the fluff is extremely high, as shown in Figure 8 A and B.

The reason why the fluff of thin fiber bundles and fluff of single fibers can occur is because the internal structure of the nonwoven fabric already contains not only fiber bundles but also finely divided fiber bundles and single fibers, making it a three-dimensional entangled body. This cannot occur with a simple three-dimensional entanglement of fiber bundles.

In other words, the presence of ultrafine single fibers not only improves the density of the nonwoven fabric and increases its strength and fullness, but also has the effect of making the surface extremely smooth.

Of course, the fluff exposed on the surface is continuous to the inside of the nonwoven fabric, and because the three-dimensional entangled structure is dense, it is extremely difficult for the fluff to come off.

On the other hand, the state of the surface fluff of nonwoven fabrics and artificial leathers consisting only of fiber bundles is as shown in Figure 8, where the fluff of thick fiber bundles is roughly protruding fluff, and the surface texture is
It has a rough texture.

The PU in Figure 8 A and B is a schematic representation of a rubber-like elastic body, and in reality it is more complex and is dispersed and filled into the fiber voids in a spongy manner, but it is easy to understand. It is expressed in block form for ease of reference.

In any case, the nonwoven fabric structure of the present invention is a nonwoven fabric in which finely divided fiber bundles and single fibers are mixed, and a knitted fabric is interposed inside without interfering with the integration of three-dimensional entanglement, Therefore, it is possible to provide a new and highly valuable leather-like product with a nubuck-like appearance.

The present invention will be explained in more detail by giving Examples and Comparative Examples below.

However, the physical properties shown in Examples and Comparative Examples are the values obtained by the following measurements.

To determine the tensile strength, a sample of length 20 cm x width 1 cm is taken, the grip length is set to 5 cm at both ends, and the sample is stretched and cut using an autograph, and the maximum strength at that time is determined.

To measure the tear strength, take a sample as shown in Figure 6A and make a cut to C from one end to the other.

Next, as shown in Figure 6B, spread the grasping length at the A and B ends by 5.
cm, the A and B ends were pulled in the direction of the arrows, and the maximum force when point C was torn was measured using an autograph.

For sewing strength, take two samples of length 10 cm x width 2 cm, overlap these two samples as shown in Figure 7 A, and then shape the overlapped part into a U-shape as shown in Figure 7. to sew.

The sewing conditions were as follows: a normal sewing machine was used, the needle was No. 11, the sewing thread was No. 50 polyester thread, and the sewing stitches were 12 stitches/3 cm.

These two samples were sewn together vertically,
Grasp both ends and pull using an autograph to measure the maximum strength (kg) when a break occurs at the seam.

Sewing strength (kg/crIL) is obtained by dividing the maximum force by the sewing width (1.5 cm) of the sample.

To determine the elongation recovery rate, a sample of length 20c1'fl x width ICIfL is taken, the upper end 5CrfL is grasped, and the sample is suspended from above and fixed.

Next, the lower end 5CIrL is grasped, a load of 1.0 kg is suspended, and the elongation is measured.

Letting the initial length be L0(1), the length L1 (crIL) when a load is applied for 10 minutes is determined, then the load is removed and the sample is left for another 10 minutes.

If the length at this time is L2 (crrL), Find the elongation recovery rate.

Compression rate and compression recovery rate are 10cfrL× from leather-like material.
Sample 10 square pieces of 10CIrt,
Stack these 10 sheets and place a thin metal plate of the same width on top of it (5
0g) was placed and left for 2 minutes, its thickness to was measured, and then a 10kg load was applied evenly over the entire surface and left for 30 minutes.

The thickness t1 after 30 minutes under load is measured, and then the load is removed and the sample is left for another 30 minutes to determine the thickness t2 at that time.

From tot1t2, the compression rate and compression recovery rate are given by.

Example 1 A stock solution of cellulose produced by the copper ammonia method was spun into water through 2000 spindles of 100 holes so that the fineness of single fibers was 0.2 denier, and each spindle of 100 holes was spun in a semi-solidified state. After converging each fiber with a convergence guide and self-adhering the single fibers to form a 20 d fiber bundle, the whole is assembled into 4
0,000 denier tow, scouring and drying.

This tow was cut into 10 mm pieces with a cutter to form short fiber bundles.

Obtained ultrafine fiber bundle staple 5007 with a length of 10 mm
was gradually added to 600 liters of water while stirring slowly into a dispersion tank containing 600 liters of water to prepare a dispersion.

Next, 2 liters of a 0.5% aqueous solution of polyacrylamide (manufactured by Meisei Kagaku Co., Ltd.) was added to this dispersion liquid to make a slurry liquid with a viscosity of 2200 cps, and the area weight was adjusted using a hydroformer type needle-slanted screen paper making machine. A short fiber paper sheet of 120 g/m2 was obtained.

A rough double-sided knitted fabric (nylon 66 40d/34f multifilament knitted fabric) with a basis weight of 40 g/m2 was spread evenly on top of this paper sheet, and then the same fabric as shown above was placed on top of the paper sheet. Area weight 70 obtained by papermaking method
g/m2 paper sheets were laminated to form a sheet with a three-layer structure.

There are no corners on the entire surface of the three-layer structure sheet. A high-pressure water stream jetted continuously at a pressure of 20 kg/cm2 from a nozzle with a diameter of 1 mm was applied once on each side, and then at a pressure of 40 kg/crr.
The front and back sides are applied twice at a pressure of 50 kg/crti, and the front and back sides are further treated once each at a pressure of 60 kg/crti.

When the cross-section of the sheet treated with high-pressure water was observed using a scanning electron microscope, no three-layer structure was observed;
The 0d fiber bundle is subdivided into thin fiber bundles and ultra-fine single fibers,
It was a three-dimensionally intertwined non-woven sheet material integrated with the knitted fabric, and had a cross-sectional structure exactly as shown in Figure 1.

The nonwoven sheet material of the present invention has a fiber bundle and a single fiber of 75%.
It was an extremely dense leather-like nonwoven fabric with a mixing ratio of :15.

The physical properties of this product were as follows.

Area weight: 230g/m2 Thickness: 0.64mm Tensile strength: Length 7.1 x Width 6. 5 (kg/cm)
Tear strength: Length 2.8 x Width 2.4 (kg) Sewing strength: Length 5.2 x Width 4. 6 (kg/cm)
Elongation recovery rate Length 73 x Width 71 (%) Compression rate 37% Compression recovery rate 63% The thus obtained integrated fiber structure of ultrafine fibers and knitted fabric was impregnated with a 15% DMF solution of polyurethane elastomer to determine the squeezing rate. It was narrowed down by a mangle at 800%.

Next, it was placed in a 30% DNF aqueous solution and left to stand for 30 minutes to fully solidify the polyurethane.

After washing and drying, the surface was brushed with sandpaper, resulting in a nubuck-like artificial leather with an extremely fine grained surface.

When this nubuck-like surface was observed with an optical microscope, it was found that the surface had downy fuzz, which was a mixture of fiber bundle fuzz and ultrafine single fiber fuzz, as shown in FIG. 8A.

The physical properties of the nubuck-like artificial leather according to the present invention were as shown below.

Fabric weight 800g/m2 Thickness 0.7mm Fiber/polyurethane = 77/28 Tensile strength Length 8.9 x Width 8. 1 (kg/crn
) Tear strength Length 3.5 x Width 3.0 (kg) Sewing strength Length 6.5 x Width 5. 8 (ky/C77L
) Elongation recovery rate Length 92 x Width 85 (%) Compression rate 27% Compression recovery rate 89% Comparative example 1 Non-woven fabric and leather-like fabric were prepared using the same raw yarn as in Example 1 except for searching the knitted fabric. I got something.

However, the obtained nonwoven fabric is a three-dimensional entangled body of fiber bundles and single fibers, and the entangled state is coarser than that of the fiber structure of Example 1, and when viewed with an electron microscope, it appears that the fibers are oriented in the vertical direction. There were fewer fibers, and the sense of fullness was naturally lower.

Also, the tensile strength of this item is 2.0 kg/cm in length and 1.0 kg/cm in width.
It was only 9kg/cm.

Next, when impregnated with polyurethane and squeezed with a mangle, the sheet material did not regain its thickness and became flat.

Next, the physical properties of the leather-like product obtained by surface raising are shown below.

Fabric weight: 225g/m2 Thickness: 0.5mm Fiber/polyurethane = 85/15 Tensile strength: Length 44 x Width 3. 7 (kg/cm) Tear strength Length 1.2 x Width 1.1 (kg) Sewing strength Length 41 x Width 8. 8 (kg/cm) Elongation recovery rate Length 45 x Width 41 (%) Compression rate 6% Compression recovery rate 65% Comparing these values with the physical properties of the leather-like material of Example 1, the tensile strength and tear The strength and sewing strength were significantly reduced, indicating that sufficient entanglement was not obtained because there was no knitted fabric.

Moreover, the reason why it is a leather-like material with no sense of fulfillment is that the thickness is 0. This can be easily understood from the fact that it is as thin as 5 mm, and that its compression ratio is only 6%, which is poor elasticity.

It is clear that the presence of a knitted fabric is an essential condition for the product of the present invention.

Example 2 Intrinsic viscosity 0. 6 6 (O-chlorophenol 35℃
) was melt-spun using a conventional method to obtain an undrawn yarn of 48 denier/266 filaments.

This undrawn yarn was stretched 3.5 times while heating at 130°C,
The film was further stretched 2.6 times on a roller at 75°C, then heat-treated on a hot plate at 150°C, and then rolled up.

The unstretched supply speed was 9 m/min.

The obtained drawn yarn had a single yarn fineness of 0.2 denier, a number of filaments of 266, a strength of 2.5 g/tenier, and an elongation of 36%.

Gather this filament into a tow shape and use a cutter to cut it into 4mm pieces.
It was made into long short fibers.

The obtained short fibers were mainly composed of fiber bundles in which 0.2 tenier ultrafine fibers were bundled into 266 fibers using a spinning oil.

The short fibers were dispersed in water to form a slurry with a concentration of 0.1%.

When we sampled the slurry and observed it under a microscope, we found that the fiber bundles were defibrated during dispersion, and that 61.3% by weight of the fiber bundles were dispersed as ultra-fine single fibers. The proportion was 38.7% by weight.

The breakdown of bundles is that 2 to 12 pieces are bundled, 13 to 30%.
1/3 was for books, and 1/3 for 31 or more books (weight).

The largest bundle observed was a bundle of 100 ultrafine threads.

In addition, polyacrylamide 20 is used as an aid for slurry adjustment.
PPm, surfactant N-7-A (Takemoto Yushi) 40P
Pm, 80 PPm of Kao P-7-A (Kao Allus), and 100 PPm of Kao P-46 (Meisei Chemical) were used.

This slurry was added to the middle layer using a two-layer paper machine.
g/m2 coarse fabric (polyethylene terephthalate 75d/36f, 1000 T/m strong twist yarn diameter) is inserted into the paper to form a three-layer laminated sheet of short fiber paper sheet/fabric/short fiber paper sheet 1・I got it.

The fabric weight of the paper sheet was 80 g/m2 for both the upper and lower layers.

Next, a high-pressure columnar water jet ejected at 8 kg/crA from a nozzle with a diameter of 2 mm was applied to the front and back sides of the three-layer sheet, and the front and back were further treated at a pressure of 25 kg/cm2 to form an entangled sheet. Obtained.

In the resulting intertwined sheet, most of the ultrafine threads were separated and dispersed into single threads and intertwined, and bundles of bundled threads were observed in some parts.

When this sheet was fluffed, it became a sheet-like product that had a soft leather-like surface, was flexible to the touch, and had excellent dimensional stability.

The cross section of this product is as shown in Figure 9, and the ratio of the ultra-fine single yarns to the bundle of ultra-fine single yarns in the product is 72.
: 28 (weight ratio).

This material (physical properties were as follows).

Fabric weight 190P/m" Thickness 0.65" Tensile strength Length 9.5 x Width 7.5 (kg/cm) Tear strength Length 1.4 x Width 1.3 (kg) Sewing strength Length 39 x Width 3. 4 (kg/cm) Elongation recovery rate Length 88 x Width 86 (%) Compression rate 29% Compression recovery rate 72% Furthermore, this interlaced sheet was treated with polyurethane resin in the same manner as in Example 1, raised and made into nubuck. obtained artificial leather.

The cross section of this sheet had a structure in which polyurethane was deposited in the interstices between the fibers as shown in the cross section of the sheet shown in FIG. 1B.

The product had appropriate elasticity and exhibited a leather-like texture with excellent dimensional stability against tension.

In addition, the surface of the product was covered with fine fuzz made of ultra-fine single yarns, giving it a fine-grained appearance and smooth feel.

The physical properties of this product were as follows.

Fabric weight 240g/m Thickness 0.67mm Fiber/polyurethane = 200/50 Tensile strength Length 12.6 x Width 12.0 (kg/cm) Tear strength Length 2.0 x Width 2.0 (kg) Sewing strength Length 5.6 x Width 4.8 (kg/cm) Elongation recovery rate Length 93 x Width 91 (%) Compression rate 21% Compression recovery rate 84%

[Brief explanation of drawings]

FIGS. 1A and 1B are diagrams schematically showing a cross section of a leather-like material having a fluffed surface of the nonwoven fabric structure of the present invention. FIG. 2 is a diagram schematically showing a cross section of a five-layer structured sheet product other than the present invention, in which there are sheet products each having a nonwoven fabric structure on the upper and lower sides, and a knitted fabric is interposed in the intermediate layer without interfering with the nonwoven fabric. be. FIG. 3 is a diagram schematically showing a cross section of a nonwoven fabric other than the present invention, which is substantially composed of fiber bundles, with its surface fluffed. FIG. 4 is a diagram schematically showing a cross section of natural leather. FIG. 5 is a diagram showing an example of an intermediate used to obtain the product of the present invention. FIG. 6 is a diagram showing the shape of a sample and measurement conditions when measuring the tear strength of a sheet-like material. FIG. 7 is a diagram showing the state of the sample and the sewn portion when measuring the sewing strength. Figure 8(a) shows the state of fluff when the surface of the leather-like product of the present invention is raised, and Figure 8(b) shows the state of the fluff when the surface of the leather-like product made of only fiber bundles other than the present invention is raised. This is a diagram schematically showing it. In the figure, a represents the cross section of the yarn constituting the knitted fabric structure, and b hereinafter represents a large undivided fiber bundle;
b' is a finely divided fiber bundle, b'' is a cross section of the fiber bundle,
c indicates an ultra-fine single fiber, d indicates a thick fiber bundle fluff with thick fiber bundles exposed on the surface, and d′ indicates a thin fiber with finely divided fiber bundles exposed on the surface and raised. The bundle fluff and e indicate the fluff of ultra-fine single fibers.

Claims (1)

[Claims] 1 Single fiber fineness 0.5 denier or less, fiber length 10 mm
The short fiber bundle of the ultrafine fibers below is formed into a sheet by a papermaking method, and then layered with knitted fabrics to form a laminate.
By impinging on the surface of this laminate a high-pressure water stream ejected at a pressure of 5 to 70 kg/cm2 from a nozzle with a hole diameter of 0.05 to 0.3 mm, the sheet-constituting fibers and the knitted fabric are three-dimensionally entangled. At this time, the short fiber bundle is defibrated by mechanical force in the process of forming the short fiber bundle into a sheet and/or the high pressure water treatment process of the laminate to form ultrafine single fibers and subdivided fiber bundles. A method for producing a nonwoven fabric structure, characterized in that short fibers and ultrafine single fibers of fiber bundles of various sizes and thicknesses are intermixed and intertwined and intertwined together with the knitted fabric.