JPH0713344B2 - Method for manufacturing sheet material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for producing a sheet-like material in which a novel nonwoven fabric and a knitted fabric have an integrated structure.

The sheet-like material according to the present invention is used for producing a leather-like material having high strength, low elongation and flexibility.

[Prior Art] Conventionally, in the production of artificial leather, a nonwoven fabric sheet and a polymer elastic body, which are advantageous in obtaining flexibility and mechanical performance similar to natural leather, are mainly used in combination. Also, various methods have been proposed.

In these general manufacturing methods, generally, flexibility and strength properties cannot be satisfied at the same time, so various means for improving strength properties have been tried in addition to conventional softening techniques. As one of them, a method of reinforcing a nonwoven fabric sheet with a knitted fabric has been proposed.

That is, for example, there is a method of sandwiching knitted fabrics and subjecting a sea-island structured fiber sheet having a length of 10 mm or less to high-speed fluid treatment (Japanese Patent Publication No. 60-29775). However, although this method has some effect on the method of obtaining a high density and short napsuede, it has a drawback that the single fiber is likely to come off and the abrasion strength is poor because the fiber length is extremely short. In addition, there is a method of needle-punching a knitted fabric between non-woven webs or on one side, but within the range of conventional studies, when a knitted fabric is used, the yarn is caught in the barb of the needle and damage to the knitted fabric yarn is large. Therefore, there is a drawback that the strength reinforcing effect is small and a sufficient expected effect cannot be obtained. not to mention,
It is necessary to increase the degree of fiber entanglement in order to improve the product's fullness and appearance quality (especially in the case of nap formation), but increasing the needle punch density to increase the degree of entanglement increases the strength of the knitted fabric. It caused a decline and was unable to satisfy both parties. In particular, when the cut end of the knitted fabric is exposed on the surface, there is a drawback that the appearance is remarkably deteriorated.

[Problems to be Solved by the Invention] An object of the present invention is a drawback in the method for forming a sheet-like material in which a conventional nonwoven fabric and a knitted fabric are entangled and integrated by needle punching. The reinforcing effect of the woven fabric is reduced, while trying to maintain the reinforcing effect of the knitted fabric solves the contradictory problem that only sheets with insufficient fiber entanglement can be obtained, and high strength and high entanglement are achieved. It is intended to provide a method for producing a sheet-like material in which a non-woven fabric and a knitted fabric are integrated, which can simultaneously achieve the above.

[Means for Solving the Problems] The method for producing a sheet-like article of the present invention that achieves the above-mentioned object has the following constitution.

That is, it is a method for producing a sheet-like product, characterized in that the web and the knitted fabric are overlapped and needle punching is performed under a condition satisfying the following formula.

D ≦ A / 2 where A: diameter of yarn constituting knitted fabric D: throat depth of needle used for needle punching Further, in the sheet-like material manufacturing method of the present invention, preferably, the web is constituted. The fibers are ultrafine fibers having a denier of 0.8 denier or less and / or fibers capable of being made into ultrafine fibers having a single fiber fineness of 0.8 denier or less, and preferably, the yarn constituting the knitted fabric is a multifilament strongly twisted yarn. It is preferable that the web is pre-entangled with a needle punch having a punch density of 20 needles / cm ² or more before being superposed with the knitted fabric and subjected to the needle punching. Also, preferably, the method for producing a sheet-like product of the present invention, wherein the needle used for the needle punch is a single barb.

[Operation] Hereinafter, the present invention will be described in detail.

As an example of one specific means for achieving the present invention,
After forming the nonwoven web, the web and the knitted fabric are overlapped and needle punched to sufficiently enhance the entanglement of the web itself and the entanglement of the web and the knitted fabric to form a non-separable integral structure. The main point is that the throat depth D of the barb of the needle used in this needle punch satisfies the relational expression of D ≦ A / 2 with respect to the diameter A of the yarn constituting the knitted fabric.

Here, the throat depth means the length from the tip of the barb to the deepest part of the valley.

First, the relationship between the throat depth (D) of the needle and other components in the present invention will be described.

The diameter A of the yarn here is an average value of the values of the yarns constituting the knitted fabric actually measured in the knitted fabric, and the individual filaments constituting the yarn or the fineness of the original yarn, It does not mean a calculated value calculated from processing conditions or the like.

This measured value is measured by sampling the knitted fabric and taking a photograph with a scanning electron microscope.When calculating the average value, the thickest part, the thinnest part and other parts in the image are calculated. This is obtained by comparing the average value obtained by measuring the diameters of 10 points at arbitrary 8 points and the length of the 500 μm scale on the image.

Further, the throat depth D of the barb is an average value in a state where there is no wear of the barb on the unused needle, and includes a normal variation in the needle manufacturing process.

When the sheet-like material obtained by the present invention is used for artificial leather, it is desirable that the basis weight of the knitted fabric be ²⁰ to 200 g / m ² , and most preferably 30 to 150 g / m ² . If the basis weight is less than 20 g / m ² , the form of the knitted fabric becomes extremely loose, and wrinkles occur when sandwiched in the middle layer part or when superposed on the surface, which makes it difficult to spread uniformly. Further, when the basis weight exceeds 200 g / m ² , the knitted fabric structure becomes dense, the penetration of the non-woven web is insufficient, and the highly entangled non-woven web does not proceed, so that it is common to make a structure that is separated and integrated. It will be difficult.

However, when the value of D becomes large, the yarn diameter A of the knitted fabric to be used must be correspondingly large, and as a result, when the basis weight of the knitted fabric is constant, the knitting density must be made small. , When the knitting density is kept constant, the basis weight must be increased.

On the other hand, if the value of D is too small, the efficiency with which the barbs grip the fibers that make up the nonwoven web is reduced, and it becomes difficult to sufficiently increase the entanglement between the webs and between the webs and the knitted fabric.

For these reasons, it is important that the throat depth (D) of the needle used in the present invention satisfies the above-mentioned relational expression D ≦ A / 2, and in general, the lower limit of the value of D is Number 10
Specifically, the range of D is generally preferably 40 μm to 100 μm, and more preferably 5 μm, since up to μm may be practical.
Those having a range of 0 μm to 70 μm are used.

The structure of the part other than the throat depth (D) of the needle used in the present invention is not particularly limited, but the relational expression between the throat length (L) and the throat depth (D) is 2.58 <tan ⁻¹ (D / L) < Satisfaction with 5.31 is the most preferable to effectively increase the entanglement. Also, the number of barbs per needle is one, that is, the use of a single barb needle is most suitable for obtaining a uniform and smooth sheet material, but of course, a general multi-barb needle is used. The effect of the present invention is not impaired even if the needle punching is performed by using.

Next, the nonwoven web of the present invention will be described.

The non-woven web is not particularly limited, natural or recycled, synthetic short fibers laminated through a card, cross wrapper, random webber, etc., spunbond,
Examples thereof include those in which long fibers are laminated, such as melt blown, and further, these fiber layers may be those in which preliminary entanglement is preliminarily given by an air flow, a liquid flow, a needle punch, or the like. .

Further, when the present invention is used for producing artificial leather, it is particularly desirable that the fibers constituting the nonwoven web are ultrafine fibers or fibers capable of being ultrafine. The ultrafine fibers or fibers that can be made into ultrafine fibers are not particularly limited, but include polyethylene terephthalate (hereinafter referred to as PET), polybutylene terephthalate (hereinafter referred to as PBT), polyester systems such as polyester elastomers, nylon 6, nylon 66, polyamides such as polyamide elastomers. System, polyurethane system,
Polymers having fiber-forming ability such as polyolefins and acrylonitriles are suitable. Among them, PET, PBT,
Nylon 6, nylon 66 and the like are particularly desirable in terms of the texture of the processed product and practical performance. Further, as the ultrafine fibers obtained by removing or peeling off some of the polymers constituting the conjugate fiber such as the sea-island type fibers, the components to be removed are, for example, polystyrene and its copolymer, polyvinyl. One or two kinds of alcohol, copolyester, copolyamide and the like can be used.

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

Further, the knitted fabric in the present invention will be described.

Regarding the types of knitted fabrics, weft knitting represented by warp knitting, tricot knitting, lace knitting and various knitted fabrics based on their knitting methods, or plain weave, twill weave, satin weaving and their weaving methods are basically used. Various kinds of fabrics are not particularly limited.

For artificial leather use, among these knitted fabrics, as a preferred one, at least a warp or a warp-twisted yarn is preferably used, and a particularly preferable one is a warp,
A knitted fabric using strong twisted yarns is good for both sides. When a strong twist yarn is used for one of the length and the width, the fiber damage is greatly suppressed by aligning and punching the needles so that the barbs of the needle face the strong twist yarn. Furthermore, as weft, SZ
It is preferable that the twists 1-1, 2-2, 4-4 and the like are alternately charged, or that S (or Z) single-twisted yarn is driven. In the case of using those in which the driving state is changed, the appearance of a grain-like texture or a levee-like texture with a natural feeling can be obtained by utilizing the torque restoring force of the strongly twisted yarn by unwinding the latent torque after needle punching. This can be done by skillfully utilizing the usual strong twist knitting fabric treatment (rubbing in hot water), but simply by adding the unraveling treatment of the latent torque of the strong twist yarn by hot water or dry heat treatment. Often the flexibility of is greatly improved.

As another case, needle-punching a woven fabric that has been subjected to torque development in advance may substantially increase the elongation of the knitted fabric and may have a reinforcing effect (reduces the breakage of the knitted fabric fiber). . Which one is selected may be appropriately determined depending on the purpose.

The twist number of the strongly twisted yarn constituting the knitted fabric is preferably 700 T / m or more, more preferably 1000 T / m or more, and most preferably 1500 T / m or more. The reason for this is that the twist count is 700
When the T / m is less than T / m, the tightness of the monofilaments constituting the yarn is insufficient, and the monofilament or some monofilaments are partially dispersed so that the relational expression D ≦ A / 2 with the throat depth is not partially satisfied. Therefore, during needle punching, the barb of the needle is caught in the portion, and the probability of partial damage tends to increase.

Further, even if the number of twists is too large, the fiber becomes too hard, and in general, it is not preferable from the viewpoint of softening the texture and entanglement,
4000 T / m or less is preferable.

As the type of strong twisted yarn used, filament yarn,
The spun yarn, the innovative spun yarn, the mixed yarn of the filament yarn and the spun yarn, the composite yarn, and the like are not particularly limited.

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

Next, the relationship between the nonwoven web and the knitted fabric will be described.

The weight ratio of the knitted fabric to the nonwoven web is preferably 70% or less, and most preferably 10 to 50%. This is because if the weight ratio of the knitted fabric to the nonwoven web exceeds 70%, the knitted fabric is likely to be exposed on the surface of the nonwoven fabric.

For the entanglement of the nonwoven web and the knitted fabric, the knitted fabric may be laminated between the webs or on one side or both sides, and the fibers may be entangled with each other by needle punching.

At this time, it is desirable that the web is preliminarily entangled by some means as described above in order to further prevent wrinkles from occurring when the web and the knitted fabric are separated and integrated by needle punching. In that case, it is particularly preferable to adopt a method of giving preliminary entanglement in advance by needle punching, and it is effective that the punch density is 20 needles / cm ² or more, and preferably 100 needles / cm ² It is better to give pre-entanglement with the above punch density, more preferably 30
Pre-entanglement is given with a punch density of 0 / cm ^{2 to} 1300 / cm ² . When the pre-entanglement has a punch density of 20 lines / cm ² or less, the width of the non-woven web leaves room for narrowing due to the needle punching after the entanglement with the knitted fabric and thereafter, so that the width This is because wrinkles occur in the knitted fabric and it becomes impossible to obtain a smooth sheet.
Further, when the punch density of the pre-entanglement is 1300 fibers / cm ² or more, the entanglement of the fibers constituting the nonwoven fabric web itself generally progresses too much, and the entanglement with the fibers constituting the knitted fabric is increased. This is because there is less room for movement to sufficiently form a bond, which is disadvantageous in realizing a non-separated integral structure in which the nonwoven web and the knitted fabric are strongly entangled.

[Examples] Examples and comparative examples will be given to more specifically describe the present invention. Of course, the present invention is not limited to these examples.

The physical properties and the like were measured by the following methods.

Tensile strength / elongation: JIS-L1079 5,12,1 yarn diameter of knitted fabric: Knitted fabric structure is sampled and photographed with a scanning electron microscope at a magnification of 80, where the thickest part and the thinnest part appear. 2 points and other 8 points total
Ten points were actually measured, and the average value was calculated from the length ratio with the 500 μm scale on the image.

Example 1 A raw material of sea-island type composite fiber having a component ratio of 80/20 consisting of polyethylene terephthalate as an island component and polystyrene as a sea component, 16 islands, denier of composite fiber 3d, fiber length of 51 mm, and crimp number of 14 mountains / inch. Using the card, cross-wrapper process to create a web, then pre-punched 400
The needle / cm ² was needle punched to create a felt having a basis weight of 210 g / m ² .

75 denier-72 filaments in the felt, twist count 2500
T / m polyester raw yarn strong twisted yarn plain weave (weave density 90
× 80 yarns / inch, basis weight 75g / m ² , measured yarn diameter A = 120
(μm) are spread evenly and overlapped, and throat depth D = 60μ
m, slow-strength 800μm single barb with needles planted from the web side
1500 pieces / cm ² , 1250 pieces / cm ² from the fabric side, 2750 pieces / cm ^{2 in} total
Was subjected to needle punching, and a sheet-like material having a basis weight of 320 g / m ² and an apparent density of 0.215 g / cm ³ was obtained.

The obtained sheet material has a smooth and uniform surface, and the cutting strength of the woven fabric in the sheet material is, as described in Table 1, vertical 10.2 kg / cm, horizontal 8.4 kg / cm, and punching. I had hardly lost my previous strength (vertical 10.7 kg / cm, horizontal 8.8 kg / cm). The tensile elongation is also as shown in Table 1.

Example 2 In the above-mentioned Example 1, the needle was inserted into the throat depth D =
A sheet-like material was obtained by processing under the same conditions except that the thickness was changed to 50 μm.

The sheet-like product thus obtained and the sheet-like product obtained in Example 1 have a smooth and uniform surface and have a good cutting strength, almost the same as those obtained in Example 1. The basis weight, strength, elongation, etc. are as described in Table 1.

Comparative Example 50 denier-48 filaments in place of the fabric to be piled up with the pre-punched felt of Example 1, polyester taffeta with a twist number of 500 T / m (weave density 96 × 84 / inch, basis weight 50 g)
/ m ² , yarn diameter measured value A = 75 μm) was used in the same manner as in Example 1, and the weight per unit area was 300 g / m ² and the apparent density was 0.210 g / cm 2.
³ sheets were obtained.

The cutting strength of the fabric in the sheet thus obtained is
3.8kg / cm, horizontal 3.6kg / cm, strong before punching (vertical)
7.2 kg / cm, horizontal 6.0 kg / cm).

Reference Example 1 By the way, the sheet-like material obtained in Example 1 was shrink-processed in hot water at 98 ° C., and the PVA solution was added to the island component in a solid state of 5%.
% And dried, the sea component was dissolved and extracted with trichlorethylene. This sheet was impregnated with a DMF solution of polyurethane (concentration: 11%) at a solid content of 30% with respect to the island component and the total polyester component of the fabric, and then the polyurethane was solidified in water. This sheet was further dipped in hot water, and the solution was repeatedly squeezed to remove PVA and DMF, dried, and then ground on a non-woven surface with sandpaper to nap. This napped sheet was subjected to jet dyeing with a disperse dye at 120 ° C. for 1 hour and finish processing to obtain a suede-like leather-like sheet having a heat of 0.9 mm and a basis weight of 390 g / m ² .

The leather-like material thus obtained was flexible and rich in richness, had an elegant and uniform surface, and had physical properties of high strength and low elongation.

Reference Example 2 Similar to Reference Example 1, the sheet-like material obtained in the above Comparative Example was treated in the same manner as in Reference Example 1 to obtain a suede-like leather-like sheet.

The leather-like material thus obtained had a poor quality appearance with spots in the deeply dyed part due to the textile fibers being cut and exposed on the surface of the ultrafine fiber layer, and was not strong and had no commercial value. .

[Effects of the Invention] According to the present invention, the following effects can be obtained.

Since the damage of the knitted fabric fiber by the needle punch can be minimized, it is possible to easily obtain a sheet-like article having a non-separable integrated structure in which the knitted fabric and the nonwoven fabric web are strongly entangled.

By applying the method of the present invention to a sheet-like material composed of a knitted woven fabric and an ultrafine fiber web, and performing a known treatment such as application of a resin binder, high strength and low elongation, a flexible and high-quality leather-like material is obtained. can get.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-6956 (JP, A) JP 62-78281 (JP, A) JP 48-16151 (JP, B1) JP 55- 26221 (JP, B2) Actual public Sho 48-34548 (JP, Y1)

Claims (5)

[Claims] 1. A method for producing a sheet-like material, which comprises stacking a web and a knitted fabric, and subjecting the web to needle punching under conditions satisfying the following equation. D ≦ A / 2 where A; diameter of yarn that constitutes knitted fabric D; throat depth of needle used for needle punching 2. The fiber constituting the web is an ultrafine fiber having a denier of 0.8 or less and / or a fiber capable of being ultrafine to a single fiber fineness of 0.8 denier or less. The method for producing a sheet-shaped product. 3. The method for producing a sheet-like article according to claim 1, wherein the yarn constituting the knitted fabric is a multifilament strongly twisted yarn. 4. The web is pre-entangled with a needle punch having a punch density of 20 needles / cm ² or more before being superposed with the knitted fabric and subjected to the needle punching. The method for producing a sheet-like article according to claim (1) or (2). 5. The needle used in the needle punch,
The method for producing a sheet-like product according to claim (1) or (2), which is a single barb.