JPH11200256A - Artificial leather comprising continuous filament nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lightweight artificial leather excellent in flexibility by impregnating a specific blend spun continuous filament nonwoven fabric containing a fiber-forming polymer as an island component with a treating agent consisting essentially of an elastic polymer, coagulating the elastic polymer and then removing the sea component. SOLUTION: Blend spun continuous filaments (having 0.1-10 de fiber fineness) containing a thermoplastic polymer having fiber-forming properties as an island component and a polyolefin-based polymer as a sea component are mutually interlaced to afford a continuous filament nonwoven fabric having 150-1,200 g/cm<2> METSUKE (mass per unit area). The resultant nonwoven fabric is then impregnated with a treating agent consisting essentially of an elastic polymer to coagulate the elastic polymer. The polyolefin-based polymer in the blend spun continuous filaments is then removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to artificial leather, and more particularly, to artificial leather using a long-fiber nonwoven fabric as a base material.

[0002]

2. Description of the Related Art Artificial leather is used for a wide variety of applications. One of the market requirements for artificial leather is to reduce the weight of the artificial leather.

In the production of artificial leather, a method has been adopted in which a nonwoven fabric made of inelastic polyester or polyamide short fibers is impregnated with an elastic polymer, mainly a polyurethane elastomer, as a binder (Japanese Patent Publication No. 42-185).
No. 99, Japanese Unexamined Patent Publication No. Hei.
2-29548, etc.). Artificial leather made by impregnating a non-woven fabric made of short fibers with a polyurethane elastomer is excellent in texture and durability, but has a poor structure because it has a dense structure filled with resin between short fibers. Difficult to reduce weight.

Japanese Patent Application Laid-Open No. 6-2267 discloses a polymer blend A comprising a polymer having good solubility as a sea component and a polymer having a fiber forming ability as an island component.
A method has been proposed in which a fibrilable composite staple fiber in which a layer and a polymer blend B layer are bonded in a lamination form into a nonwoven fabric.

However, these methods require a series of large-scale equipment such as a raw cotton supply unit, a fiber opening device, a carding machine, a cross lay machine, and a needle punching device. In addition, the production speed is extremely slow, and the production speed will be increased. Or when a finer denier mixed spun staple is hanged on a carding machine, wrapping around the card cylinder occurs, productivity decreases, neps and spots occur on the web, and the resulting nonwoven fabric There is a problem that the quality is significantly reduced. Further, when trying to obtain a thinner artificial leather, it is necessary to improve the strength of the artificial leather. However, in the above-described method, since it is necessary to pass through a card machine, the strength of the artificial leather due to the entanglement of short fibers is increased. Improvement was difficult due to the fiber length.

On the other hand, Japanese Patent Application Laid-Open No. 3-213555 proposes that a split type two-component composite hollow long fiber is formed into a nonwoven fabric. According to the publication, this nonwoven fabric can be used for clothing, bags, and the like. However, in the artificial leather based on a nonwoven fabric proposed in the publication, since the fibers are of a split-type two-component type, the fibers after splitting have a smaller size than the fibers obtained by melt-spinning a blended polymer. The fiber diameter was large, the compactness was poor, the flexibility as artificial leather, and the touch on the surface were poor.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an artificial leather which is lightweight and excellent in flexibility.

[0008]

Means for Solving the Problems In view of the above-mentioned prior art, the present inventors have made intensive studies especially on a nonwoven fabric used as a base material for artificial leather, and have completed the present invention.

That is, the objects of the present invention are as follows:
(A) A mixed fiber spun long fiber in which a thermoplastic polymer having a fiber-forming ability as an island component and a polyolefin-based polymer as a sea component are disposed on a long-fiber nonwoven fabric simultaneously satisfying the requirements of (D). Be configured. (B) The mixed spun long fibers constituting the long-fiber nonwoven fabric are 0.1% or less.
It is a long fiber having a fiber fineness of 1 to 10 de. (C) The mixed spun long fibers constituting the long-fiber nonwoven fabric are mutually entangled between the mixed spun long fibers. (D) The basis weight is 150 to 1200 g / cm ² .

[0010] It can be achieved by artificial leather comprising a long-fiber nonwoven fabric obtained by impregnating and coagulating a treating agent containing an elastic polymer as a main component and then removing the polyolefin-based polymer in the mixed spun long fiber. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a long-fiber nonwoven fabric as a base material of artificial leather needs to be composed of mixed spun long fibers. The long-fiber nonwoven fabric obtained from the mixed spun long fiber has less crimp than the short fiber, and the fibers are entangled in a good state at the time of entanglement by the needle punch,
Since the fiber density increases and the tissue becomes dense, the resulting artificial leather has a soft and stretch-free texture.

In the mixed spun filament of the present invention, it is necessary that a thermoplastic polymer as an island component and a polyolefin-based polymer as a sea component are disposed.

The polyolefin-based polymer acts as a binder in the long-fiber nonwoven fabric and fixes long fibers made of a thermoplastic polymer to each other to improve the strength of the nonwoven fabric. The mixed spun long fiber is a long fiber having a fineness of 0.1 to 10 de, and the mixed spun long fiber must be entangled with each other. When the fineness is less than 0.1 de, the obtained nonwoven fabric has insufficient strength as a base material for artificial leather. On the other hand, if it exceeds 10 de, a nonwoven fabric suitable for the base material for artificial leather intended by the present invention cannot be obtained.
In addition, since the mixed spun filaments are entangled with each other, sufficient nonwoven fabric strength can be obtained. However, in this entangled state, only a part of the filaments is not pulled, and delamination and collapse of form are caused. It is sufficient if it does not occur.

The basis weight of the nonwoven fabric is 150 to 1200.
g / cm ² . The basis weight is 150 g / cm ²
When the amount is less than the above, the strength is lowered depending on the intended use. On the other hand, when the amount exceeds 1200 g / cm ² , the effect of improving the strength is not further exhibited, and the productivity becomes poor.

[0015] The mixed spun filament further comprises a thermoplastic polymer (A) having a fiber-forming ability as an island component (hereinafter sometimes simply referred to as a thermoplastic polymer (A)) and a sea component. Blend (I) comprising a polyolefin (B) as a thermoplastic polymer (A ′) as an island component (hereinafter sometimes simply referred to as a thermoplastic polymer (A ′)) and a sea component. And a polymer blend (II) composed of a polyolefin (B ′) as above, is preferably a mixed composite spun filament bonded to a multilayer bonding type. Here, if the polymer blend (I) and the polymer blend (II) are different, the thermoplastic polymers (A) and (A ') may be the same polymer or may be different or different. The polyolefin (B) and the polyolefin (B ') may be the same polymer or different.

[0016] In the mixed composite spun filament, when the multi-layered fiber cross-sectional shape is adopted, the fiber density at the time of entanglement is further increased, and the sense of elongation in artificial leather is further improved. It is preferable because it becomes large.

The thermoplastic polymer of the present invention is not limited as long as it is a polymer having a fiber-forming ability and does not dissolve under the conditions in which the polyolefin-based polymer dissolves. Because of the ease of
Examples of the thermoplastic polymer include polyethylene terephthalate, copolymerized polyethylene terephthalate containing 80 mol% or more of ethylene terephthalate units, nylon-6, nylon-66, nylon-610, nylon-12, polypropylene, polyurethane elastomer, polyester elastomer, and polyamide elastomer. These may be used alone or in combination of two or more. In addition, carbon black, titanium oxide, aluminum oxide, silicon oxide, calcium carbonate, mica, metal fine powder, organic pigments, inorganic pigments and the like may be added as long as the object of the present invention is achieved. The additive has an effect of increasing or decreasing the melt viscosity of the thermoplastic polymer as well as a coloring effect on the thermoplastic polymer, and is effective in adjusting the fiber cross section of the mixed spun filament.

In the present invention, the polyolefin-based polymer functions as a binder in the long-fiber nonwoven fabric, and is impregnated with an elastic resin such as a polyurethane polymer when producing artificial leather. Since it is necessary to remove the polyolefin-based polymer, it is preferable to use a polyolefin-based polymer that does not dissolve or alter the thermoplastic polymer and the elastic polymer and is soluble in hot toluene.

Examples of such a polyolefin-based polymer soluble in hot toluene include polyethylene, polypropylene, and polybutylene. These may be used alone or in combination of two or more.

In producing the mixed spun filament according to the present invention, it is necessary to melt and mix the thermoplastic polymer and the polyolefin-based polymer in the same molten system, and perform the mixed spinning. The supply ratio of the polyolefin-based polymer is not particularly limited as long as both are mixed, but the physical properties of the obtained mixed spun long fiber, the removal of the polyolefin-based polymer during the production of artificial leather, and the like, In the area ratio of the fiber cross section, (70: 3
It is preferable that the extruder is supplied to the extruder, melt-kneaded so as to be 0) to (30:70), and then discharged from the spinneret to obtain long fibers.

In the present invention, any known method can be used to form a long-fiber nonwoven fabric.
In particular, it is preferable that the long fibers obtained by the mixed spinning are drawn at a high speed, jetted and collected on a collection net, and then the long fibers are three-dimensionally entangled. Here, as means for high-speed traction, air soccer or the like can be mentioned, and the speed may be about 3000 to 8000 m / min, and the long fibers discharged from the spinneret are ejected by an ejector or the like for each weight. High speed towing at speed is sufficient.

Further, in the present invention, it is preferable to spray / collect a fine material obtained by drawing the long fiber at high speed onto a collection net. In order to collect the thinned material neatly on the collection net, and to make the aspect ratio of the nonwoven fabric close to 1,
Immediately below each ejector, a dispersing plate is provided so that the long fibers collide and change the direction at the same time as uniform opening,
It is preferable that the dispersion plate is rocked at a constant cycle to randomize the direction of the long fibers collected on the collection net. Here, it is preferable that the dispersion plate is flat or concave and made of metal from the viewpoint of wear resistance. Further, in order to prevent blow-up, turning up, and the like of the collected thinned material, a large amount of air may be sucked by providing an exhaust duct below the collecting net. The speed at which the collection net is moved may be in the range of 1 to 50 m / min.

Next, the thinned materials in the obtained nonwoven fabric are three-dimensionally entangled. As the method of three-dimensionally entangled, either fluid entanglement or mechanical entanglement can be adopted, and the three-dimensional entanglement can be performed in the vertical direction of the nonwoven fabric. The fibers may be entangled with each other to such an extent that they do not peel off in layers.

In the present invention, when a mixed conjugate spun filament is used as the mixed spun filament, for example,
A blended polymer (I) in which two kinds of polymer components are blended and a blended polymer (II) in which another two kinds of polymer components different from the above polymer components are blended are separately melt-kneaded by an extruder, and are laminated and laminated. A method of supplying each of these to the spinnerets and performing composite spinning in the same manner as ordinary melt composite spinning may be adopted.

In the present invention, the long-fiber non-woven fabric obtained by the above-described operation is used as a base material to form artificial leather. A known method for producing artificial leather may be employed. That is, the long fiber nonwoven fabric is impregnated with a treatment agent mainly composed of an elastic polymer, followed by solidifying the elastic polymer component, and then dissolving and removing the polyolefin-based polymer in the nonwoven fabric in the mixed spun long fibers. . .

[0026]

The artificial leather of the present invention is not only a thin artificial leather product, but also has excellent characteristics such as flexibility and tear strength, and has a soft feeling of standing up.

[0027]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In addition, each evaluation in an Example was performed based on the following method.

Card passing property: The degree of clogging of short fibers, generation of scum, etc. in the carding process were visually judged according to the following criteria. ○ ・ ・ ・ No abnormality. Δ: short fibers are caught, scum is generated, etc., but passes through the process. C: Short fibers are caught, scum is generated, and do not pass through the process.

Needle punch characteristics: Abnormal noise, needle breakage, etc., in the needle punching process were judged according to the following criteria. ◎ ・ ・ ・ There is no abnormality at all. ○ ・ ・ ・ Needle break does not occur, but a slight noise is heard. △ ・ ・ ・ Needle breakage and noise. ×: Needle breakage frequently occurs and noise is generated.

Tear strength: After making artificial leather into a rectangular sample piece having a length of 8 cm and a width of 2.5 cm, a short side of two opposing sides is gripped with a chuck, and a distance between the chucks is set to 5 cm to extend the leather. The chuck interval was increased at a speed of 200% / min, and the strength at the time when the sample piece was broken was obtained.

Visual Judgment: Five skilled workers were selected indiscriminately, and a sensory test was performed on the manufactured artificial leather, and a relative comparison was made by visual observation. ◎ ・ ・ ・ Very smooth and dense surface condition 〇 ・ ・ ・ Smooth and dense surface condition × ・ ・ ・ Wide spacing between fibers and fine irregularities on the surface

Texture: Five skilled workers were selected indiscriminately, a sensory test was performed on the manufactured nonwoven fabric, a relative comparison was made by touch, and evaluation was performed according to the following criteria. ◎ ・ ・ ・ Very soft and has a smooth touch on the surface タ ッ チ が 〇 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い 柔 ら か い も の も の も の も の も の も のSomething ×… hard feeling without stretch

Example 1 50 parts of a polyethylene chip having a melt flow rate of 50 g / 10 min measured at 260 ° C. and 50 parts of a nylon-6 chip having a melt flow rate of 3.8 g / 10 min measured at 260 ° C. And the mixture is supplied to an extruder. The temperature of the melting section, the tip of the screw, the temperature of the spinning cylinder is set at 285 ° C., the temperature of the spinneret is set at 260 ° C., the diameter of the spinneret is 0.3 mm, and the number of holes is 20.
From the spinneret with 20 holes x 2 rows arranged,
After discharging at a rate of 300 g / min per die and drawing the long fibers at a high speed with an ejector pressure of 6 kg / cm ² , the filaments are collided with a dispersion plate together with an air flow to open the filaments, and the sheet weight is 300 g / m ² . Seat width 2000c
m was collected using a collection net conveyor adjusted to obtain a non-woven fabric.

At the lower part of the collection net conveyor, a suction box is divided into four zones in the sheet length direction, and the suction air amount is 4000 Nm ^{3 in} total of the four zones.
/ Min via the collection net conveyor.

The dispersion plate was swung 180 times per minute so that the slender material became more uniform as it was collected on the net, so that the direction of the filament was randomized. The fineness of the refined product was 1.5 de.

Next, the obtained nonwoven fabric was subjected to needle punching to obtain a long fiber entangled nonwoven fabric having a basis weight of 350 g / m ² . The apparent density of the nonwoven fabric is 0.15 g / cm ³
Met.

The obtained long-fiber-entangled nonwoven fabric is heat-treated with hot air at 140 ° C. to soften the polyethylene in the long-fiber and partially fuse the long-fibers constituting the non-woven fabric.
Press the apparent density of the nonwoven fabric to 0.25 g / cm ³
It was adjusted to become.

Next, the nonwoven fabric was impregnated with a 15% dimethylformamide solution of a polyether polyurethane,
After coagulation in a water bath, the mixture was dried, and then the polyethylene in the nonwoven fabric was extracted and removed to obtain an artificial leather in which polyurethane was impregnated in an entangled nonwoven fabric composed of ultrafine fibers. The basis weight of the leather is 325 g / cm ³ , the composition ratio (wt%) of long fibers to polyurethane constituting the nonwoven fabric, (55.
3): (44.7). Table 1 shows the physical properties of the leather.

Comparative Example 1 A polyethylene chip 50 having a melt flow rate of 50 g / 10 min measured at 260 ° C. instead of the long fiber entangled nonwoven fabric in Example 1.
Part and the melt flow rate measured at 260 ° C.
After mixing with 50 parts of 8 g / 10 min nylon-6 chips and supplying the mixture to an extruder, the mixture was spun by a usual melt spinning method, and then the obtained long fiber was drawn, mechanically crimped, and cut. An artificial leather was obtained by performing the same operation as in Example 2 except that a short-fiber-entangled nonwoven fabric in which a mixed spun short fiber having a fineness of 5 de was used as a nonwoven fabric was used.
Table 1 shows the physical properties of the obtained artificial leather. As shown in Table 1, the artificial leather obtained by the operation of Example 1 had higher tear strength, a soft texture and a smooth appearance as compared with the artificial leather obtained by the operation of Comparative Example 1. .

Example 2 50 parts of a polyethylene chip having a melt flow rate of 50 g / 10 min measured at 260 ° C. and 50 parts of a nylon-6 chip having a melt flow rate of 3.8 g / 10 min measured at 260 ° C. And the mixture is supplied to an extruder. The temperature of the melting section, the temperature of the screw tip, and the temperature of the spinning cylinder are set to 285 ° C.
Melt flow rate measured at 60 ° C. is 50 g / 10
50 parts of polyethylene chips and 50 parts of nylon-6 chips having a melt flow rate of 4.7 g / 10 min measured at 260 ° C. are supplied to an extruder, and a melting section, a screw tip temperature, and spinning are performed. The cylinder temperature was set to 295 ° C., the spinneret temperature was set to 260 ° C., the hole diameter of the laminated composite spinneret was 0.3 mm, and the number of holes was 200.
From the spinneret with 20 holes x 2 rows
After discharging at a rate of 300 g / min per spinneret, the continuous filament was drawn at a high speed with an ejector pressure of 6 kg / cm ² , then collided with a dispersion plate together with an air flow to open the filament, and the sheet weight was 300 g / m ² . Width 20
After collecting on a collecting net conveyor adjusted to be 00 cm, hot air of 100 ° C. was blown to obtain a nonwoven fabric in which latent crimps became apparent.

Under the collection net conveyor, a suction box is divided into four zones in the sheet length direction, and the suction air amount is 4000 Nm ^{3 in} total of the four zones.
/ Min via the collection net conveyor.

The dispersion plate was swung 180 times per minute so that the thinned material became more uniform as it was collected on the net, so that the direction of the filament was randomized. The fineness of the refined product was 1.5 de.

Next, the obtained long fiber entangled nonwoven fabric was subjected to needle punching to obtain an entangled nonwoven fabric having a basis weight of 350 g / m ² . The apparent density of the nonwoven fabric is 0.25 g / c.
m ³ .

The entangled non-woven fabric obtained is heat-treated with hot air at 140 ° C. to soften the polyethylene in the fibers, and the fibers constituting the non-woven fabric are partially fused. The density was adjusted to be 0.3 g / cm ³ .

Next, the nonwoven fabric was impregnated with a 15% solution of polyether polyurethane in dimethylformamide,
After coagulation in a water bath, drying was performed, and polyethylene in the nonwoven fabric was extracted and removed to obtain artificial leather composed of ultrafine fibers and impregnated nonwoven fabric impregnated with polyurethane.
The basis weight of the leather is 325 g / cm ² , the composition ratio (wt%) of fiber to polyurethane constituting the nonwoven fabric, (55.3):
(44.7). Table 1 shows the physical properties of the leather.

[Comparative Example 2] A polyethylene chip 5 having a melt flow rate measured at 260 ° C of 50 g / 10 min in place of the long fiber entangled nonwoven fabric in Example 2.
After mixing 0 parts and 50 parts of nylon-6 chips having a melt flow rate of 3.8 g / 10 min measured at 260 ° C. and feeding the mixture to an extruder, the mixture is spun by a usual melt spinning method and then obtained. The same operation is performed to produce artificial leather by using a short-fiber entangled nonwoven fabric obtained by stretching a drawn fiber, applying a mechanical crimp, cutting the mixed fiber and forming a non-woven mixed spun short fiber having a fineness of 5 de. Obtained. Table 1 shows the physical properties of the obtained artificial leather. As shown in Table 1, the artificial leather obtained by the operation of Example 2 had higher tear strength than the artificial leather obtained by the operation of Comparative Example 1,
The appearance was smooth with a soft texture.

[0047]

[Table 1]

Claims (6)

[Claims] 1. A long-fiber nonwoven fabric which simultaneously satisfies the following requirements (A) to (D): (A) a thermoplastic polymer having a fiber-forming ability as an island component and a polyolefin-based polymer as a sea component And that it is composed of mixed spun filaments. (B) The mixed spun long fibers constituting the long-fiber nonwoven fabric are 0.1% or less.
It is a long fiber having a fiber fineness of 1 to 10 de. (C) The mixed spun long fibers constituting the long-fiber nonwoven fabric are mutually entangled between the mixed spun long fibers. (D) The basis weight is 150 to 1200 g / cm ² . An artificial leather comprising a long-fiber nonwoven fabric obtained by impregnating and coagulating a treating agent containing an elastic polymer as a main component and removing a polyolefin-based polymer in the mixed spun long fiber. 2. The mixed spun long fiber constituting the long-fiber nonwoven fabric is a mixed composite spun long fiber obtained by laminating the following polymer blend (I) and polymer blend (II) in a multilayer bonding type. Artificial leather. Polymer blend (I): a polymer blend of a thermoplastic polymer (A) having a fiber-forming ability as an island component and a polyolefin-based polymer (B) as a sea component. Polymer blend (II): a polymer blend comprising a thermoplastic polymer (A ') having a fiber-forming ability as an island component and a polyolefin-based polymer (B') as a sea component. 3. A thermoplastic polymer having a fiber-forming ability,
Polyethylene terephthalate, copolymerized polyethylene terephthalate containing at least 80 mol% of ethylene terephthalate units, nylon-6, nylon-66, nylon-6
The artificial leather according to claim 1, which is at least one polymer selected from the group consisting of 10, nylon-12, polypropylene, polyurethane elastomer, polyester elastomer, and polyamide elastomer. 4. The artificial leather according to claim 1, wherein the polyolefin-based polymer is soluble in hot toluene. 5. The polyolefin-based polymer is at least one polymer selected from the group consisting of polyethylene, polypropylene, and polybutylene.
The artificial leather described. 6. A long-fiber nonwoven fabric obtained by melting and spinning a thermoplastic polymer having a fiber-forming ability and a polyolefin-based polymer, and a thermoplastic polymer having a fiber-forming ability as an island component, High-speed traction of mixed spun filaments with a polyolefin polymer as a sea component,
The artificial leather according to claim 1 or 2, wherein the obtained thinned material is obtained by spraying and collecting the thinned material on a collection net, and then three-dimensionally confounding the thinned materials.