JPH0313326A - Sheet like article composed of high strength wet nonwoven fabric and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain a sheet like article rich in smoothness and having a soft feeling and excellent properties like natural leather by interlacing staple fibers composed of a monofilament having a specific diameter and a specific fiber length/diameter ratio with each other to form a high strength wet nonwoven fabric and coating said fabric with a polymer. CONSTITUTION:At first, staple fibers f1-f7 composed of a monofilament having a diameter of 3-20mum and an L/D ratio of 800-2000 are prepared and dispersed in water in a concn. of 0.1-3% to be formed into sheet by a Fourdrinier machine or a cylinder machine. The obtained sheet is treated with high speed fluid stream to mutually interlace staple fibers f1-f7 three-dimensionally (interlacing points a1-a7). The surface layer part of the obtained interlaced sheet is coated with a polymer solution or dispersion to be solidified by a wet or dry system. The sheet-like article thus obtained is suitably used in shoes materials, a bag, a cover material or a seat cover material.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a sheet-like material having a soft texture and high strength suitable for uses such as shoes, bags, bags, tablecloths, etc., and a method for producing the same. be.

More specifically, the present invention relates to a sheet-like product in which a high-strength wet-laid nonwoven fabric in which specific short fibers are intertwined with each other is coated with a polymer, and a method for producing the same.

[Conventional technology]

So-called coating fabrics, which are obtained by coating woven and knitted fabrics with high molecular weight polymers such as polyurethane, polyamide, and vinyl chloride, are an inexpensive and functional alternative to natural leather for shoes, bags, bags, interior decoration, and surface materials. It is widely used as a product. However, there are drawbacks such as the texture is paper-like and hard without a sense of fullness, and the fibers fray from the cut surface. Improvements in these points are desired.

On the other hand, coated fabricators using non-woven fabrics are also popular due to their low cost due to their high productivity, as well as their excellent properties such as a solid texture due to the characteristics of the structure of non-woven fabrics and no formation of holes. It is used as a substitute for textiles. However, on the other hand, nonwoven fabrics have the disadvantage that they generally have lower strength than woven fabrics, and particularly low glabella peel strength, which is important in coating fabricators.

One of the required properties of a coating fabric is that the peel strength between the fiber sheet and the coating layer of a high molecular weight polymer such as polyurethane or vinyl chloride has a practically sufficient strength. If this peel strength is low, the coating layer will peel off during use, exposing a portion of the underlying fiber sheet, resulting in an unsightly appearance and a significant loss of commercial value, which is not preferable. When a nonwoven fabric is used as the base fabric, for example, when a nonwoven fabric obtained by needle-punching a spunbond or carded sheet is used as the base fabric, the glabella peel strength inside the nonwoven fabric is low, resulting in a separation between the covering layer and the nonwoven fabric. Even if the glabella peel strength of the layer is sufficiently strong, the nonwoven fabric will peel from inside, and the covering layer will eventually peel off with the nonwoven fabric partially adhered, exposing the L nonwoven fabric surface. For this reason, when a nonwoven fabric is used as a base fabric, a method is generally used in which an elastic polymer such as polyurethane, acrylic ester, SBR, NBR, etc. is used as a binder to reinforce the delamination strength of the nonwoven fabric. In this case, the L-woven fabric had a paper-like texture and could only have a lack of a luxurious feel.

Therefore, as a base fabric for coating fabricators,
Currently, there is currently no nonwoven fabric that takes advantage of the high productivity of nonwoven fabrics, has practically sufficient strength, especially glabella peel strength, and has a soft texture.

[Problem to be solved by the invention]

The present invention aims to improve the glabellar peel strength, which is a problem of nonwovens used as the base fabric of coating fabrics, and to provide a novel nonwoven coating fabric that is substantially binder-free and has a soft texture. be.

[Means to solve the problem]

The present inventor has diligently studied the above-mentioned problems and has arrived at the present invention.

The present invention is made of a wet-laid nonwoven fabric in which short fibers having a single yarn diameter of 3 to 20 μm and a ratio L/D of fiber length to single yarn diameter of 800 to 2.000 are intertwined with each other and a high molecular polymer. It is a sheet-like product consisting of a coating layer.

The sheet-like article of the present invention can achieve the object of the present invention of providing a coated fabricator that has both physical properties such as a delamination strength rate that is sufficiently strong for practical use and a soft texture.

In the method for producing a sheet-like product of the present invention, the diameter of the single yarn is 3 to 2.
0μm, ratio L/D of fiber length to single yarn diameter is 800
~2,000 short fibers are formed into a sheet by a papermaking method, and then the short fibers are three-dimensionally entangled with each other by high-speed fluid flow treatment.
This manufacturing method is characterized by forming a coating layer made of a high molecular weight polymer on the obtained entangled sheet.

The sheet-like article of the present invention is made of a combination of a wet-laid nonwoven fabric made of short fibers having a specific shape and in which the short fibers are three-dimensionally entangled with each other, and a high molecular weight polymer coated on the surface of the wet-laid nonwoven fabric. This is an essential condition, and a new coated fabric can be obtained that has sufficient practical strength and a soft texture compared to conventional conniting fabrics using nonwoven fabrics.

In the present invention, the constituent yarns have a single yarn diameter of 3 to 20 μm.
, the ratio L/D of fiber length to single yarn diameter is 800 to 2.0
It is necessary to satisfy both the two elements of 00. If the single yarn diameter is less than 3 μm, even if L/D is in the above range, the single yarn tenacity will be too low, and the nonwoven fabric will have low glabella peel strength, tensile strength, tear strength, etc. Even if a nonwoven fabric is impregnated with a high molecular weight elastic polymer in a large amount, for example, 50% by weight or more, there will be disadvantages such as low tear strength and extremely hard texture, which will not achieve the strength and soft texture that are the objectives of the present invention. It is not possible to achieve both. If the single yarn diameter exceeds 20 μm, even if L/D is within the specified range of the present invention, the fibers are thick and the surface density and uniformity of the nonwoven fabric will be lost. When such a nonwoven fabric is coated with a high molecular weight polymer, the surface of the formed coating layer becomes uneven, resulting in an undesirable quality.

Therefore, from the point of view of strength and uniformity, the single yarn diameter should be 3 to 2.
It is necessary that the volume is 0 μl, and it is more preferable that the volume is 5 to 15 μl.

The L/D of the raw yarn is 800 to 800 within the specified range of fiber diameters mentioned above.
Must be 2.000.

The inventor's studies have revealed that the L/D of the yarn has an important relationship with the ease with which the fibers intertwine with each other.
When D is less than 800 and when it exceeds 2,000, the desired nonwoven fabric strength cannot be obtained, and practical high strength can only be obtained in the specific range of 800 to 2,000 according to the present invention. This surprising fact can be estimated as follows. That is, the ease of movement of the fibers due to columnar water flow, etc. is greater as L/D is smaller, that is, the thicker and shorter the fibers are, and the entanglement between the fibers becomes greater. On the other hand, the number of contact points between fibers increases as the fibers become thinner and longer, that is, the L/D becomes larger. However, L
If /D is too large, the movement of the fibers during intertwining is suppressed, and the entanglement between the fibers becomes smaller. Therefore, it is understood that there is an optimal range of L/D at which the fiber-to-fiber intertwining density is maximum, and this range is 800 to 2,000.

The wet entangled nonwoven fabric in which short fibers having the above specific single yarn diameter and L/D are entangled with each other has a sufficiently strong glabella peel strength in the range of 0.5 to 3.0 kg/cm. However, if the weight is less than 1 kg/cm, sheet materials directly coated with a polymer without impregnating with a binder cannot be used for shoe lining materials, upholstery materials, etc. during use. This may cause peeling between the eyebrows. In order to prevent this, it is necessary to impregnate the nonwoven fabric with a relatively large amount (20 to 30% by weight of the nonwoven fabric) of binder.As a result, the texture becomes hard, which is not preferable. In this respect, the glabellar peel strength of the wet entangled nonwoven fabric that is a component of the present invention is preferably 1 kg/cm or more.

When the state of entanglement of the wet entangled nonwoven fabric of the present invention is expressed using, for example, the numerical value of the distance between fiber entanglement points, it is in the range of 30 to 350 μm. If it is 300 μm or more, the intertwined state of the fibers is relatively loose, the interlayer peel strength is low, and a relatively large amount of binder impregnation is required, which is not preferable. In this respect, the average distance between fiber entanglement points is preferably 300 pm or less.

The distance between fiber entanglement points here means JP-A-58-191
This is a value measured by the following method known in Japanese Patent No. 280, and is a measure of the intertwining density between L fibers, and the smaller the value, the more dense the intertwining is. FIG. 1 is an enlarged schematic diagram of the constituent fibers of a wet-laid nonwoven fabric when observed from the surface in a plane direction. The constituent fibers are f, , f2, f3-, and the point where any two of them intertwine, f+, fz, is the point at which the upper fiber ``2'' intersects under the other fibers. Follow the path to the point and set the point where it intersects as 82.

Similarly, a31 a4 +・-. Next, the linear horizontal distance between the intersecting points obtained in this way al + al +
az + a31-'- is measured, the average value of these many measured values is determined, and this is taken as the distance between the fiber entanglement points.

The nonwoven fabric of the present invention is characterized in that sufficient strength can be obtained without containing a binder such as polyurethane, but it is also preferable to impregnate it with 10% by weight or less of a binder, if necessary. For example, 10% when used to add elasticity to the texture in addition to the original softness, or to prevent fuzz from falling on the back side where there is no coating layer. It is a preferred embodiment to impregnate the following small amounts of binder.

Next, the coating layer of the present invention is integrated with the nonwoven fabric of the present invention, which is made of a high molecular weight polymer, with sufficient adhesive strength. In the present invention, since the surface of the nonwoven fabric is very smooth and uniform, the back surface of the coating layer is also smooth and uniform. Any pattern on the surface of the coating layer can be formed using an engraved roll, a patterned release pattern, or the like depending on the application.

The covering layer may be a single layer or a plurality of laminated layers, and the cross-sectional structure of the covering layer may be a fine porous structure or a substantially non-porous structure. A typical embodiment that is appropriately designed depending on the application is a microporous coating layer that adheres to the nonwoven fabric, and a non-porous coating layer is laminated on top of that, and embossing, etc. An example is an embodiment in which a "grain"-like pattern of natural leather is applied using an engraved roll.

The yarn material of the short fibers used in the present invention is not particularly limited.

Polyamide fibers such as nylon 6, nylon 66, and nylon 610, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, polyolefin fibers such as polypropylene and polyethylene, regenerated cellulose fibers such as rayon, etc., have the fiber diameter and L/L of the present invention.
It is preferably used within the range of D.

The polymer constituting the coating layer is also not limited, but polyurethane, polyamide, polyvinyl chloride, polyacrylic acid ester, polyamino acid, and the like are preferably used.

There are no particular limitations on the elastomeric polymer that can be impregnated into the nonwoven fabric if necessary, and examples include polyamide, polyester, polyvinyl chloride, polyacrylate copolymer, polyurethane, styrene-butadiene copolymer, and acrylonitrile-butadiene copolymer. conjugates, polyamino acids, etc. are used.

Next, a method for manufacturing a sheet-like article according to the present invention will be explained.

First, the diameter of the single yarn is 3~20pm, and the L/D is 800~2.
,000 short fibers are prepared. This is 0.
Disperse in water to a concentration of 1 to 3%.

At this time, it is preferable to add a small amount of a dispersant such as polyacrylamide (FAA). This slurry is made into paper using a fourdrinier type, circular net type, or other type of paper making machine.

The basis weight is set depending on the intended use of the coating fabricator, but is generally in the range of 30 to 500 g/%. Regarding the type of short fibers, the single yarn diameter of the present invention, L
The material and shape are appropriately selected within the range of /D. Regarding the number of types, it is also preferable to use a mixture of two or more types of raw threads having different materials and/or shapes.

The resulting paper sheet is entangled by a high-speed fluid stream. The fluid here includes liquid or gas, but water is most preferable in terms of ease of handling, high collision energy as a fluid, and cost. When using water, the water pressure varies depending on the type of yarn used, date, and processing speed, but is 10 to 200 kg/aj, preferably 15 to 150 kg/aj.
Collision is performed in the range of g/cTB. When the processing speed is constant, it is preferable to process at a relatively low pressure when the short fiber has a small basis weight, and to process at a high pressure when the fabric weight is large. The diameter of the nozzle that injects the water stream is preferably 0.01 to 0.5 m111. The trajectory shape of the water stream may be a straight line in the same direction as the papermaking sheet's traveling direction, or the header to which the nozzle is attached may be rotated. It may also be a curved shape obtained by motion or vibration motion that reciprocates at right angles to the direction of travel of the sheet. The intertwining of the multiple spiral water flow trajectories obtained by rotational motion increases the jetting area of the water jet on the sheet per nozzle, which is efficient, and at the same time improves the surface smoothness of the nonwoven fabric when forming the coating layer. It is extremely effective as a means to induce consistency, uniformity, and denseness. The distance between the nozzle and the paper sheet is preferably 10 to 60 cylinders.

In order to entangle the water flow without leaving traces, it is often preferable not to make the water flow diameter too large, most preferably 50 mm or less. If the interval is too small, water jets may easily penetrate the sheet depending on the water pressure, and the intertwining of the short fibers may not proceed sufficiently. It is preferable that a porous member such as a wire mesh or a perforated plate be placed under the paper sheet, and the suction dewatering be performed from underneath. In order to entangle the short fibers, it is preferable that the waste water is sufficiently separated and dehydrated. If the separation and dehydration are sufficient, the short fibers are often not entangled with each other sufficiently. The hydroentangling treatment may be carried out by treating only one side of the paper sheet or by alternately treating both the front and back sides. When the smoothness and uniformity of the surface of the nonwoven fabric are particularly important, a method of spraying water multiple times and increasing the water pressure sequentially is a method, or after spraying at high pressure, 40 to 120 mesh is applied between the nozzle and the paper sheet. A method of inserting a fine wire mesh to make a high-pressure water stream and spraying it, 1 when spraying at high pressure.
Preferably used is a method in which a relatively coarse wire mesh of 0 to 20 mesh is inserted between the nozzle and the paper sheet and the high-pressure water stream is cut into dotted locus.

The surface layer of the thus obtained entangled sheet is coated with the above-mentioned solution or dispersion of the high molecular weight polymer. As a coating means, methods such as gravure coating, knife coating, slit coating, reverse roll coating, and spraying are used, and the coating is solidified wet or dry.

If necessary, it is also preferable to apply a pattern to the coated layer by pressing an embossing roll or a patterned sheet with a pattern on the surface to apply pressure. Here, it is also a preferable method to subject the entangled sheet to a treatment such as pressing with a roll before coating with the high molecular weight polymer. Furthermore, treatments such as finishing agents, dyeing, rubbing, etc. may be performed as necessary. If the nonwoven fabric is impregnated with a small amount of binder before applying the high molecular weight polymer to the nonwoven fabric, the nonwoven fabric is impregnated with a solution or dispersion of the above-mentioned high molecular weight elastomeric polymer, and the nonwoven fabric is wet-coagulated or dry-coagulated to adhere. . It is also preferable to add a colorant such as a pigment to the solution or dispersion. From the viewpoint of texture, it is also preferable that the amount of adhesive is 10% by weight or less based on the nonwoven fabric.

The sheet-like product of the present invention obtained in this way has a coating layer formed on the surface layer of a nonwoven fabric with substantially no binder, high strength, and excellent surface smoothness, and has an extremely smooth texture. This is an unprecedented coated fabric that is soft and has natural fine grains on the coating layer.
It is suitably used for bags, bags, covering materials, seat cover materials, etc.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the Examples, the measured values were determined by the following method, and all L% is by weight.

1) Tensile strength: JIS L 1096 strip method 2) Tear strength: JIS L 1096 single-kung method 3) N peel strength: Cut the nonwoven fabric to a width of 2.5 cm and a length of 13 cm.

Adhesive tape (manufactured by Sony Chemical ■, D3) was applied to this sample.
After adhering 200), 200
℃, press for 30 seconds to stick together.

A slit is made between the adhesive tape and the nonwoven fabric of the measurement sample thus obtained, and both ends are gripped with the chuck of the autograph to perform the measurement.The measurement conditions of the autograph are set as follows.

Tensile speed: 10cm/win Chart speed: 10cIl/ll1in In this case, the tape is strong and the tape and nonwoven fabric are firmly bonded, so when the tape of the measurement sample is peeled off from the measurement sample, the tape is The adhesive surface between the cut L tape and the nonwoven fabric is not peeled off, and the peeling force acts to peel off a portion of the nonwoven fabric from the other portion. Therefore, the glabella peel strength of the nonwoven fabric can be measured by this method.

From the stress-strain curve obtained when performing the above measurement using an autograph, three of the larger intensity values and three of the smaller intensity values are selected, and the average value of the six values in total is obtained. The number of test samples for measurement is 5.

This kind of measurement is carried out in the vertical direction (MD) and horizontal direction (MD) of the nonwoven fabric.
CD), and the vertical/horizontal average value is taken as the interlayer peel strength of the nonwoven fabric.

4) Flexibility: JIS L 1096 45' cantilever method The average value of the vertical direction (MD) and the horizontal direction (CD) is defined as L flexibility.

5) Average distance between fiber entanglement points: 100 by scanning electron microscope
Measurements were made at twice the magnification, and the average value of 50 measurements was taken.

Example 1 1211fi 1.5d (13μm) nylon 6 fiber
(L/D=923) and dispersed in water to make a slurry with a concentration of 1%. This slurry was made into paper using an inclined fourdrinier paper making machine to obtain a sheet having a basis weight of 150 g/ld. This sheet has nozzle diameters of 0 and 2rm, pitch between nozzles of 5Inl.
I. The short fibers were entangled by jetting a columnar water stream with a water pressure of 40 kg/d from a large number of nozzles with 18 rows. The distance between the nozzle and the paper sheet was 30 rm, and an 80-mesh wire mesh made of stainless steel was used as a supporting member under the paper sheet, and water was suction-dehydrated through the wire mesh. Similar treatment was applied to the opposite side of the sheet. Next, the water pressure was set at 15 kg/cd, and a 60 mesh stainless wire mesh was inserted between the nozzle and the sheet to spray water to treat the surface, and the same treatment was applied to the opposite side. Thereafter, it was dried to obtain an entangled sheet. The physical properties of this entangled sheet were as follows.

Tensile strength (vertical/"I"): Tear strength (vertical/"I"): Peeling strength between the eyebrows ・Flexibility (vertical/3 pieces average): 1Q, Q/ 8.7 kg/cm 4.3/3.8 kg 2.3 kg/cm 7 m Distance between fiber entanglement points = 110 μm The surface of this intertwined sheet was coated with dimethylformamide via roll of polyethylene adipate-based polyurethane prepared in advance, and then coagulated in water at room temperature. Next, on the formed coating layer, a 25% DMF solution of polyurethane with the same composition and hardness as the polyurethane used earlier was coated with the same gravure roll, and the DMF was evaporated. It was further pressed with a heated embossing roll to form a natural leather-like grain, and finished by lightly rubbing.

The physical properties of the sheet-like material obtained in this way are as follows: It has an extremely soft texture, the grain pattern on the surface is natural and fine, and it has sufficient strength to withstand tension, tearing, and delamination. It was something.

Tensile strength (vertical/:I): 12.1/9.
4 kg/cm tear strength (vertical/: 4 pieces):
4.9/4.3 kg Peeling strength: 2
．． 1 kg/cm Softness: 581 Comparative Example 1 Short fibers of nylon 6 fibers with a length of 3 d (18.5 μm) and a length of 3 m (L/D = 162) were processed in the same manner as in Example 1 to obtain a 150 g/rrf A paper-made sheet was obtained. This paper sheet was subjected to an entanglement treatment using a columnar water stream in the same manner as in Example 1. The obtained entangled sheet showed the following physical properties,
The strength was extremely low and could not be put to practical use.

Tensile strength (vertical/'3): 1.8/1.
3 kg/cm tear strength (riy/yogo):
0.510.4 kg Peeling strength: 0.
3 kg/cm Flexibility (vertical/3' average): 5
3mm Distance between fiber entanglement points = 250μm To reinforce this low strength, 15% of polyurethane
Polyurethane was impregnated with a DMF solution and wet-coagulated in water to give a coating weight of 40% to the entangled sheet, but the texture was hard (flexibility: 93 plates) and the tensile strength further decreased. / horizontal 0.3 / 0.2 kg)
It was not possible.

Comparative Example 2 Id (10 μm) of polyethylene terephthalate fiber 3
A sheet having a fabric weight of 100 g/rd was obtained using short fibers having a length of 0 ma+ (L/D=3000) in the same manner as in Example 1. At this time, many parts of the fibers dispersed in water were observed where the filaments were not opened into individual filaments but were bundled together, and where short fibers were entangled with each other and formed into clumps. The dispersion state was poor. This paper sheet was subjected to an entanglement treatment using a columnar water stream in the same manner as in Example 1, but the entanglement of the short fibers with each other was very weak.

Tensile strength (vertical/:I): 3.7/2.
8 kg/cm tear strength (Yi/W):
1.6/1.4 kg Peeling strength: 0
．． 2 kg/cm flexibility (vertical/horizontal average): 7
Distance between 1mm fiber entanglement points: 3IOμm Further, this sheet was coated with polyurethane by a dry method, but the above-mentioned thread-like lumps of the sheet made the coating layer uneven and had no commercial value.

Example 2 Single yarn fineness of polyethylene terephthalate fiber 0, 15d
(3.9μm), length 5iun (L/D=1
The short fibers of No. 282) were made into paper in the same manner as in Example I to obtain a paper sheet having a basis weight of 140 g/rd. This was carried out using the same nozzle as in Example 1 at a processing speed of 5 m. / minute,
Nozzle header rotation speed 120 rpm 111, water pressure 35 k
Columnar water jets were sequentially sprayed onto both the front and back sides of the paper sheet, with a g/c nozzle and the paper sheet having a spacing of 50 mm, and a 16-mesh stainless wire mesh inserted between the nozzle and the paper sheet. The physical properties of the obtained entangled sheet were as follows: The surface of the L sheet was smooth, and substantially no traces of columnar water jets were observed.

Tensile strength (vertical/3 pieces): 6.5/6.1
kg/cm tear strength (vertical/'3g):
2.7/2.3 kg delamination strength
: 1.9 kg/cm Flexibility:
49+um Distance between intertwined fiber points: 73 μm This intertwined sheet was coated with a 20% DMF solution of polyethylene adipate glycol polyurethane using a gravure roll, and then the DMF was evaporated off with hot air at 130°C. The coating amount was 20g/ryf. The coated fabric thus obtained had an excellent appearance, with the surface of the coating layer being mirror-like and smooth, and when lightly rubbed, a pattern similar to the grain of natural leather was naturally formed. The physical properties were as follows.

Tensile strength (vertical/E) Tear strength (vertical/I) Peeling strength Flexibility Distance between fiber entanglement points [Effects of the invention] The sheet-like material made of the high-strength wet-laid nonwoven fabric of the present invention, that is, the coated fabric, has the following properties: Since it is based on a non-woven fabric with good uniformity and high strength, the surface of the coating layer is extremely smooth, and since it is essentially a binder-free non-woven fabric, it has an excellent soft texture and a natural texture similar to natural leather. Provides excellent performance with fine grains.

[Brief explanation of drawings]

FIG. 1 is an enlarged schematic diagram of the constituent fibers when observed from one surface in the planar direction of the nonwoven fabric according to the present invention. f1-f, - Constituent fibers a1-a, - Intertwining points of constituent fibers.

Claims (2)

[Claims] 1. Consists of a wet-laid nonwoven fabric in which short fibers with a single yarn diameter of 3 to 20 μm and a ratio L/D of fiber length L to single yarn diameter D of 800 to 2,000 are entangled with each other and a coating layer of a high molecular polymer. sheet-like material. 2. Single yarn diameter 3 to 20 μm, fiber length L and single yarn diameter D
Short fibers with a ratio L/D of 800 to 2,000 are formed into a sheet by a papermaking method, and then the short fibers are three-dimensionally entangled with each other by high-speed fluid flow treatment, and the resulting entangled sheet is coated with a polymer. 1. A method for producing a sheet-like article, comprising forming a coating layer.