JPH1193082A - Nonwoven fabric for artificial leather and production of artificial leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a nonwoven fabric for a flexible and high-strength artificial leather. SOLUTION: This nonwove fabric for an artificial leather having >=1.0 kg/cm ply separation strength in a nonwoven fabric layer is obtained by using a conjugated spun fiber having a withdrawal resistance value of the conjugated spun fiber within the range of 10-60 g/g in the nonwoven fabric comprising the conjugated spun fiber consisting essentially of a polyamide or a polyester and a polyolefin capable of being attenuated to <=0.2 de ultrafine size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric for artificial leather with high delamination, comprising ultrafine raw cotton obtained by compound-spinning a polyamide or polyester and polyolefin that can be ultrafine to 0.2 de or less, and this nonwoven fabric. The present invention relates to a method for producing a supple, high-strength artificial leather made of ultrafine polyamide and polyurethane by impregnating and coating polyurethane and extracting polyolefin using the method.

[0002]

2. Description of the Related Art Composite spinning using polyamide or polyester and polyolefin, non-woven fabric is impregnated and solidified by impregnating a polymer elastic body, and polyolefin is extracted and ultra-fine. Is known.

[0003] In general, fibers obtained by complex spinning of polyamide or polyester and polyolefin are made of polyolefin having a low density, a low melting point and a low degree of polymerization in order to be easily dissolved in a solvent for extracting the polyolefin, for example, toluene. ing. For this reason, the raw cotton strength is weak, and in the process of forming the nonwoven fabric, the fiber is cut at the time of needle punching and the strength is not obtained, or the olefin on the fiber surface is softened by frictional heat, and the frictional resistance with the needle is significantly increased, The phenomenon that the needle stuck is occurring. In order to reduce the load on the needle, the depth of the needle is reduced, the number of needle punches is reduced, and the number of barbs of the needle is reduced. Therefore, the nonwoven fabric was inevitably low in delamination strength, that is, only nonwoven fabric having low entanglement was obtained. To increase the fiber strength and reduce the frictional resistance of the fiber surface, olefins with high melt viscosity, that is, those with high density and melting point, can be used, but the extractability with toluene decreases, and non-woven fabrics and artificial leather However, there was a drawback that the artificial leather had a strong feeling as an artificial leather.

[0004]

SUMMARY OF THE INVENTION The present inventors have found that in the case of artificial leather with silver, the delamination strength of the nonwoven fabric is 1.0 kg / cm.
If it is less than 1, the fiber at the interface between the grain surface layer and the fibrous material is easily pulled out, and a product having a peel strength of 3.0 kg / cm or more cannot be stably obtained. I noticed that there was a problem of turning over. Further, in the case of a suede-like sheet, there is a problem that the nap fibers are likely to fall off or come off from the surface.

[0005] Therefore, in the case of artificial leather with silver, the surface of the nonwoven fabric is fluffed by polishing, the resin whose surface has high peeling strength is lowered, or the porosity of the elastic polymer is increased to increase the peeling. He was strong. For this reason, when artificial leather is used, it is inevitable that the surface has large irregularities or becomes hard.

In the case of artificial leather of suede tone, after polishing, a solvent of a polymer elastic material used for impregnation is applied from the surface or another resin solution is applied to spin off the fibers. Therefore, the process becomes complicated, and the development of a nonwoven fabric having a delamination strength of 1.0 kg / cm or more has been awaited.

[0007]

In view of the above, the present inventors have made intensive studies and found that the crimping performance of a composite spun fiber mainly composed of a polyamide or polyester and a polyolefin, which can be ultrafinely reduced to 0.2 de or less. By lowering the entanglement resistance, it is possible to reduce the load on the needle when forming the nonwoven fabric and prevent fiber cutting and needle breakage, increase the entanglement of the fiber with the needle, and increase the delamination strength of the nonwoven fabric. It has been found that it can be as high as 1.0 kg / cm or more.

If the non-woven fabric is used, it is impregnated with polyurethane, coated if necessary, coagulated and dried,
It has been found that the strength of artificial leather finished by extracting polyolefin can be increased.

That is, the present invention relates to a non-woven fabric composed of a composite spun fiber mainly composed of a polyamide or polyester and a polyolefin, which can be finely reduced to 0.2 de or less, wherein the drawing resistance value of the composite spun fiber is 10 to 60 g / g.
A nonwoven fabric for artificial leather having a delamination strength of 1.0 kg / cm or more in a nonwoven fabric layer obtained by using a conjugate spun fiber having a range of: and a polyamide or polyester and a polyolefin which can be ultrafinely reduced to 0.2 de or less. Manufacture of artificial leather consisting of ultrafine fibers and polyurethane by impregnating a nonwoven fabric consisting of ultrafine composite spun fibers as the main component with a solution or dispersion of polyurethane, coating and coagulating as necessary, and extracting polyolefin. At this time, the value of the drawing resistance of the conjugate spun fiber used as the nonwoven fabric is 1
This is a method for producing artificial leather, characterized by using a nonwoven fabric having a delamination strength of 1.0 kg / cm or more, which is produced using a material in the range of 0 to 60 g / g. Hereinafter, the present invention will be described in detail.

The polyamide used in the present invention includes nylon 6, nylon 66, nylon 610 and nylon 12, and the polyester includes polyethylene terephthalate, polybutylene terephthalate, copolymerized polyethylene terephthalate and the like. Polyolefins are generally polyethylene, polypropylene and the like, and polyethylene is often used because of its cost and versatility. Among polyethylenes, low-density polyethylene is frequently used because of its extractability.

In the case of forming a composite spun fiber comprising a polyamide or polyester and a polyolefin, which can be finely reduced to 0.2 de or less, a sea-island structure fiber, particularly a mixed spun fiber, comprising polyamide or polyester as a disperse phase and low density polyethylene as a dispersion medium. Alternatively, the multi-layered composite fiber is excellent in terms of flexibility and flexibility as a sheet-like material. Light stabilizers and various additives for stabilizing the spinning condition can be used in the polyolefin. It is also possible to color the polyamide or polyester by adding a pigment such as carbon.

The fiber obtained by the composite spinning is subjected to stretching, crimping, application of an oil agent, and the like, and cut into an appropriate cut length to obtain raw cotton. As the denier of the raw cotton, one having a thickness of 2 to 8 denier and a cut length of 51 to 64 mm is preferable in terms of card passing property and needle punch. Here, the pullout resistance of the raw cotton was measured, and the pullout resistance value was 10 to 60 g /
It is important to be in the range of g. Preferably 15 to 3
A range of 0 g / g is appropriate. Pull-out resistance value is 10 /
If it is lower than g, the raw cotton is not entangled with each other and cannot be applied to the card. Conversely, if the pull-out resistance value is greater than 60 g / g, interphase separation will be lower than 1.0 kg / cm, which is problematic in terms of durability in production. The pullout resistance of raw cotton is measured as follows.

[Measurement method of pull-out resistance] 100 g of raw cotton was weighed and placed on a feed lattice of a card having a width of 45 cm and a length of 1 g.
Set the fleece so that it is 5cm, put the card on it and use it as a sliver to collect 2m, of which 20cm
To make 6 samples. Using a drawing compression tester, the test length is 10 cm, the head speed is 20 cm / min, the chart speed is 80 cm / min, the stretching speed is 200% / min, the full scale is 400 g, the temperature is 26 ° C., and the humidity is 60%.

In order to produce the raw cotton used in the present invention, the spinning temperature for melt-spinning a mixture of polyamide and polyolefin is 240 to 260 ° C., and the spinning speed is 50.
It is preferably performed at 0 to 1500 m / min. The obtained undrawn yarn is subjected to a drawing temperature of 50 to 90 ° C., a draw ratio of 2 to 4 times, and a drawing speed of 50 to 300 m / min. Usually, the stretching is performed by two-stage stretching, and an appropriate oil agent can be dispersed and attached to warm water or the like. After the stretching, the fiber is crimped by a crimping machine (stuffing box), and cut into a fiber length of 25 to 200 mm after heat setting.

As factors for adjusting the pull-out resistance, crimping conditions are selected to adjust the crimping temperature, the indentation pressure, the number of crimps, the degree of crimping, and the frictional resistance between fibers and fibers or between fibers and metals. Can be achieved by depositing a moderate amount of a high oil solution. In addition, it is possible to optimize both the crimp and the oil agent to match the pull-out resistance.

In the case of ordinary fibers, for example, polyester having a cut length of 51 mm at 2 to 8 de, the pull-out resistance is 120.
When the content is within this range, a nonwoven fabric having good cardability and needle punching property and high delamination strength can be stably obtained. However, if the pull-out resistance is set to 70 g / g or less, the connection of the fleece with a normal card is poor, and a nonwoven fabric cannot be obtained.

In the case of a composite spun fiber comprising a polyamide or polyester and a polyolefin, the reason is 10 to 60.
It is guessed that the cardability can be obtained with a pull-out resistance value lower than g / g and the kneepan property can be improved. Since the melting point of the polyolefin is low, the fiber surface frictional resistance is added in addition to the mountain valley caused by mechanical crimping. However, it is considered that even though the pullout resistance is apparently low statically, the pullout resistance increases dynamically. The raw cotton thus produced is applied to a card to form a random web or a cross lay web.
Laminate to the desired weight and thickness. Generally 300-1500
g / m ² . Then, needle punching is performed by a conventionally known method to obtain an entangled nonwoven fabric. Punch conditions can be set according to the respective applications.

The density of the artificial leather with silver is needle-punched at a density of 500 to 1000 pieces / cm ² , and the density of the artificial leather with suede is 1000 to 30.
The range of 00 fibers / cm ² is preferable.

It is preferable to increase the implantation depth as far as possible without causing surface irregularities or a needle pattern, from the viewpoint of increasing the delamination strength. The efficiency of the needle used is preferably as large as possible, but it can be selected from 1 to 9 barbs as long as needle breakage and fiber cutting do not occur. The delamination strength of the nonwoven fabric thus obtained is measured as follows.

[Measurement method of delamination strength of nonwoven fabric] Three samples of 10 cm long x 3 cm wide are taken from the center and left and right sides of the nonwoven fabric with the length direction of the nonwoven fabric as the longitudinal direction, and the intermediate layer of the cross section of the sample is taken. Loosen by hand and peel up and down
The peel strength is measured by sandwiching it up and down with Tensilon. The average value of the three sheets is defined as the delamination strength.

The nonwoven fabric thus obtained is impregnated with a polyurethane solution or dispersion and, if necessary, coated to obtain an artificial leather substrate. Various polyurethanes such as polyether, polyester, and carbonate polyurethanes as polyol components, and diphenylmethane diisocyanate components to diphenylmethane diisocyanate, tolylene diisocyanate, and isophorone diisocyanate can be used as the polyol component. Further, there are a solution type dissolved in DMF and a type dispersed in water, and both types can be used.

Next, the polyolefin is extracted using a solvent that dissolves the polyolefin, and the polyolefin is refined. As the extraction solvent, olefin is dissolved, polyamide, polyester,
The polyurethane can be any solvent that does not dissolve. General-purpose solvents such as toluene, xylene and trichlene are preferred. Particularly, toluene is preferably used. Since the extractability increases at a high temperature, it is preferable to heat the mixture to about 80 ° C.

[0023] Of the artificial leather sheets thus miniaturized, those with silver are coated by gravure with a finishing polyurethane in which a pigment is added to the surface coat layer, embossed, and embossed to the surface of natural leather. By rubbing, it is possible to obtain a very supple and highly flexible artificial leather. Since the delamination of the nonwoven fabric is high, that is, the entanglement is high, the peeling strength between the polyurethane coat layer and the polyamide or polyester fibrous layer is high, and it is suitable for basket shoes, running shoes, spike shoes and the like and is practically useful.

On the other hand, if the surface is not coated with polyurethane, the surface can be polished and dyed after extraction to give a suede-like artificial leather having very chalk mark properties. Since the suede-like artificial leather has a strong entanglement of the fiber on the surface, there is no slip-off of the nap fiber, and the sliced one for clothing is strong and practically useful.

[0025]

Next, the present invention will be described with reference to specific examples.
The present invention is not limited to these examples. The percentages used herein are based on the weight of the substrate, unless otherwise specified.

Example 1 (Preparation of raw cotton) Nylon 6 having a melt index of 20,
5 polyethylene chips with a melt index of 50
The chip was blended at a ratio of 0:50 and supplied to an extruder at a spinning temperature of 250 ° C. and a nozzle diameter of 0.25.
The fiber was spun from a spinneret having a nozzle of 1080 mm and a number of 1080 nozzles at a winding speed of 700 m / min. The obtained unspun mixed yarn is mixed with 6
At the same time, it is stretched 2.5 times at 0 ° C.
After mechanical crimping, it was cut into a length of 51 mm. The fineness of this product was 8 de, and the physical properties of raw cotton were as follows. Oil agent: potassium salt of octyl phosphate 0.48% Crimp: Number of crimps: 19.5 / inch Crimp degree: 10% Residual crimp: 6.5% Pull-out resistance: 20 g / g

(Preparation of non-woven fabric) The above-mentioned raw cotton is put on a roller card, laminated by a cross layer, and punched with a needle of 3 barbs at a needle density of 1000 needles / cm ² to obtain a basis weight of 450 g / m ² and a thickness of 2. A 4 mm nonwoven fabric was made. When the delamination strength of this nonwoven fabric was measured,
It was 2.5 kg / cm.

[Example 2] Polyethylene and nylon 6 chips were melt-mixed and spun to a ratio of 60:40, stretched, crimped, and cut under the same conditions as in Example 1 to 7 de × 5.
1 mm of mixed spun raw cotton was obtained. The raw cotton properties were as follows. Oil agent: potassium salt of octyl phosphate 0.48% Crimp: Number of crimps: 19 / inch Crimp degree: 9.1% Residual crimp: 6.8% Pull-out resistance: 15 g / g Needle punching was performed with a barb needle at a needle density of 1400 needles / cm ² to prepare a nonwoven fabric having a basis weight of 570 g / m ² and a thickness of 2.8 mm. The delamination strength of this product was 3.93 kg / cm.

[Comparative Example 1] The following raw cotton was prepared by strengthening the crimping conditions under the conditions of Example 1. Oil agent: potassium salt of octyl phosphate 0.345% Crimp: Number of crimps: 14.9 / inch Crimp degree: 14.7% Residual crimp: 9.7% Pull-out resistance: 121 g / g This raw cotton The delamination strength of the nonwoven fabric obtained by using the above method is 0.1.
It was 3 kg / cm.

Comparative Example 2 The following raw cotton was obtained under the same conditions as in Example 1 except that the concentration of the oil agent was increased. Oil agent: potassium salt of octyl phosphate 0.890% Crimp: Number of crimps: 16.9 / inch Crimp degree: 10.4% Residual crimp: 7.4% Pull-out resistance: 101 g / g 0.5kg delamination strength of non-woven fabric using
/ Cm.

Example 3 The nonwoven fabric obtained in Example 1 was heated at 150 ° C. and then nipped to a thickness of 1.9 mm, impregnated with 12% polyurethane, and further treated with 20% urethane. Wet coagulation as a coat, 80 ℃ after drying
The polyethylene was extracted with toluene. 4 rolls of a polyurethane for surface finishing to which a white pigment was added were applied to this base material using a 110 mesh gravure, and emboss rolls at 180 ° C. were used to impart pore-like grain. When rubbed, it was very soft, and the peel strength of the coat layer and the impregnated layer was measured to be as high as 3.5 kg / cm. When this product was used for running shoes, it had a good foot contact and did not cause any problem even if worn for 3 months or more.

Comparative Example 3 Using the nonwoven fabric obtained in Comparative Example 1, the peel strength between the coat layer and the fibrous layer was measured in the same manner as in Example 5, and the running strength was 2.5 kg / cm. It was uneasy for shoes.

Example 4 The nonwoven fabric obtained in Example 1 was heated at 150 ° C. and then nip to a thickness of 1.75 mm.
Next, a 14% -concentration polyurethane solution was impregnated, and the resin on the surface was scraped off and solidified with water to prepare an impregnated base material having no resin layer on the surface. After drying, polyethylene was extracted with toluene at 80 ° C. to obtain an ultrafine fiber sheet. The surface of the substrate was polished with a 320 mesh sandpaper,
When finish polishing was performed with 0 mesh, a suede-like sheet whose surface was covered with ultrafine fibers was obtained. This was sliced to 0.45 mm, dyed beige with a gold-containing dye, rubbed and brushed, and found to be as good as natural leather suede in terms of chalk marks and sliminess. The raised fibers on the surface of the base material did not come off even when scratched with a claw, and had no practical problem.

[0034]

According to the present invention, a non-woven fabric for artificial leather having strong delamination can be easily produced, and the artificial leather made by using the non-woven fabric has high strength such as peeling strength, and also has high strength such as falling off of fibers. Not be an excellent product.

Claims (2)

[Claims] 1. A non-woven fabric comprising a composite spun fiber mainly composed of a polyamide or polyester and a polyolefin which can be ultrafinely reduced to 0.2 de or less, wherein the drawing resistance value of the composite spun fiber is in the range of 10 to 60 g / g. A nonwoven fabric for artificial leather having a delamination strength of 1.0 kg / cm or more in a nonwoven fabric layer obtained using fibers. 2. A nonwoven fabric comprising ultrafine conjugated spun fibers mainly composed of a polyamide or polyester and a polyolefin which can be ultrafinely reduced to 0.2 de or less, is impregnated with a solution or dispersion of polyurethane and coated as required. In the production of artificial leather comprising ultrafine fibers and polyurethane by coagulating and then extracting polyolefin, the value of the drawing resistance of the composite spun fibers used as the nonwoven fabric is 1
A method for producing artificial leather, comprising using a nonwoven fabric having a delamination strength of 1.0 kg / cm or more, which is produced by using a nonwoven fabric having a range of 0 to 60 g / g.