JPH0653995B2 - Base fabric for artificial laser and method for producing the same - Google Patents

Description

[Detailed Description of the Invention] {Field of industrial application} The present invention relates to a base fabric for artificial leather comprising a nonwoven fabric containing a urethane resin and a method for producing the same.

{Prior Art} Artificial leather such as PVC leather and urethane leather uses woven fabrics and knitted fabrics as the base fabric.
It has the ability to withstand the use of leather substitutes and has been widely used so far.

However, since these conventional artificial leathers use a woven or knitted fabric as a base fabric, for example, a thread is frayed from a cut end, or a two-layer structure of a resin layer and a woven or knitted fabric can be seen at a glance. It had the drawback of lacking in physical experience.

In order to improve these drawbacks, studies have been made to use a non-woven fabric having a structure similar to leather as a base fabric.

{Problems to be Solved by the Invention} However, nonwoven fabrics generally have the drawbacks of being hard to the touch and being paper-like. That is, since it has a binder and a molten fiber for the purpose of imparting dimensional stability and strength, the slippage between the constituent fibers during bending is fixed, and as a result, the flexibility is significantly impaired. For this reason, the leather formed by using these non-woven fabrics as a base fabric lacks flexibility and has a very low commercial value even though the threads are frayed and the feeling of unity is improved.

On the other hand, the needle-punched non-woven fabric can hardly be used as a leather base fabric for the following reasons.

Although the thickness of leather varies depending on the application, even thin ones are 0.5 to 1 mm (for example, clothing, bags, bags, etc.) and thick ones are 1 to 2 mm (for shoes). About half the thickness is used. The entanglement by the needle punch has a coarse density, and it is difficult to make a material having a thickness of 1 mm or less in terms of strength.

There are needle holes and irregularities. As the surface quality is poor, it lacks a high-class feel as leather.

Thus, in manufacturing artificial leather, the use of non-woven fabrics other than woven fabrics and knits as a base fabric for the artificial leather has been considered, but artificial leather obtained by containing a resin in these artificial leather base fabrics. There was also a problem with its manufacturing method.

That is, it has been proposed to use, as a base fabric for artificial leather, a non-woven fabric by needle punching, as well as a entangled non-woven fabric with a high-speed jetting fluid (Japanese Patent Publication No. 59-42108, Japanese Patent Publication No. 53-786373, Japanese Patent Publication No. 54-78373). -26302
No.), all of which are for manufacturing artificial leather integrally by applying and impregnating a resin to a entangled nonwoven fabric which is a base fabric. This entangled non-woven fabric is inferior in dimensional stability because it is simply entangled with constituent fibers.

For this reason, in manufacturing artificial leather, in the process of coating or laminating the entangled nonwoven fabric that is the base fabric, the entangled nonwoven fabric is stretched by applying tension in the longitudinal direction (feeding direction). As a result of being greatly shrunk in a certain direction and being coated in that state, there is a problem that artificial leather with a prescribed width cannot be manufactured.
In addition, the entangled nonwoven fabric that is the base fabric is pulled in the longitudinal direction, and coating is performed in a state where the constituent short fibers of the base fabric are oriented in the longitudinal direction.As a result, the artificial leather obtained is easily stretched in the lateral direction. In addition, there is a problem that the elongation recovery is poor and the shape is easily lost.

(Object of the Invention) An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and has the following configuration.

(Solution) That is to say, the gist of the base fabric for artificial leather according to the present invention is that a specific resin is applied to the base fabric to make an artificial leather, which is an artificial leather before the specific resin is applied. In the leather base cloth, the base cloth is formed by impregnating a nonwoven fabric formed by interlacing short fibers with urethane resin, and the base cloth has an elongation recovery rate of 70% or more.

Further, in the artificial leather base cloth, the non-woven fabric has a tensile strength of 1 lb / inch or more per unit weight of 1 ounce / square yard when the urethane resin impregnated in the artificial leather base cloth is removed. Is to have

Further, in the artificial leather base fabric, the urethane resin has a film characteristic that the stress at 100% elongation is 25 kg / cm ² or less.

Next, the gist of the method for producing a base fabric for artificial leather according to the present invention is that a specific resin is applied to the base fabric to make an artificial leather, the artificial leather before the specific resin is applied. In the method for producing a base fabric for use in manufacturing, a non-woven fabric having a tensile strength of 1 lb / inch or more per unit weight of 1 ounce / square yard is entangled with each other, and the stress at 100% elongation is 25 kg as a film property. / Cm ² It is to impregnate urethane resin below.

(Operation) The artificial leather base fabric according to the present invention is constituted by impregnating a urethane resin into a non-woven fabric in which short fibers are entangled with each other, and coating or laminating a specific resin on the artificial leather base fabric. , Artificial leather can be obtained. That is, the problem due to the orientation in the longitudinal direction (feed direction) of the short fibers constituting the non-woven fabric generated during the production of the artificial leather base fabric is solved, and the produced artificial leather base fabric has almost isotropic, Moreover, a product having a specified width can be obtained. Therefore, when the artificial leather is manufactured by using the obtained artificial leather base cloth, the artificial leather base cloth has almost no longitudinal elongation or lateral contraction, and thus the manufactured artificial leather has a directional direction of elongation. And has excellent elongation recovery.

The present inventors targeted a non-woven fabric made of short fibers as a non-woven fabric used as a base fabric. This non-woven fabric does not use a binder or molten fiber, but entangles the constituent fibers with a hydraulic jet to give dimensional stability and cooperation,
Since there is no adhesive part, the constituent fibers slip when bending,
Since the mutual positions are moved, the above-mentioned rough feeling and paper-like feeling are remarkably improved.

The hydraulic jet treatment in the present invention can be performed, for example, under the following conditions.

A web formed from polyester staples
It is placed on a metal screen with a plain weave pattern of 80 mesh / inch and a porosity of 31%, and is passed at a speed of 20 to 30 yards / minute under a row of vertical hydraulic jet streams. The stream of water was placed 2 inches above the web 1
40 mils per inch diameter 7 mils (1 mil equals 1
/ 1000 inch) and the web is subjected to the following three stages of hydraulic treatment. Water pressure in the first stage is 200 pounds per square inch;
Square inches, the third stage is set at 800 pounds per square inch. The web is then turned inside out and the side in contact with the screen is subjected to a similar hydraulic jet treatment.

As described above, the present invention comprises a web of short fibers which is entangled with each other by entanglement of constituent fibers with a hydraulic jet so as not to step on a resin adhesive or an inter-fiber fusion bonded portion, and entangled with 1 oz / Square yard (33.9g /
per weight per unit area of m ^2), 1 pounds per inch (178.6
A non-woven fabric (hereinafter referred to as spunlace fabric) having a tensile strength of g / cm) or more can be obtained.

As expected, the leather formed by using the spunlace cloth as the base cloth has improved thread fraying, has a sense of unity, and has the same or better flexibility as the leather using the conventional woven or knitted base cloth. A feel was obtained.

However, since spunlaced fabric does not have a bonding part with binder or molten fiber, bending and stretching cause the constituent fibers to slip and move relative to each other, which makes the leather softer in terms of product characteristics. However, compared to conventional non-woven fabrics, this results in lower dimensional stability, causing the width management problem during coating (or laminating) and the anisotropy problem of leather products described in the prior art. It became clear.

As a remedy for this, a pretreatment with a resin that does not significantly impair the original flexibility of the nonwoven fabric was examined.

As the resin, acryl, vinyl acetate copolymer, vinyl chloride, vinylidene chloride, SBR, NBR, EVA, etc., which are usually used in the above-mentioned non-woven fabric production, cause feel hardening, so that elasticity and flexibility in the present invention A urethane resin that is given and can achieve dimensional stability is suitable, and when the urethane resin is filmed according to JIS K6301 and the stress for elongation is measured, the stress at 100% elongation (100% modulus) is 25 kg. It has been found that a urethane resin having a very easy stretchability of less than / cm ² is suitable.

The urethane-based processing agent generally used has a resin dissolved in a solvent such as dimethylformamide (hereinafter referred to as DMF), an emulsified resin in water, or a special block. There is a reactive urethane or the like in which an aqueous solution of a prepolmer or a water emulsion is treated on a cloth and then heated to cleave the blocking agent and polymerize.

It was confirmed that these resins have different processing conditions, but as long as the resins satisfy the above characteristic values, any type can improve the dimensional stability while maintaining a soft feeling.

The artificial leather base fabric treated with this urethane resin has an elongation recovery rate of 70% or more according to the following measuring method, and further, the urethane resin and other accessories are removed, and the fiber structure alone is used. When taken out, the non-woven fabric retains its form due to the entanglement of short fibers and has the properties described below.

That is, it does not include a resin adhesive or a fusion bond between fibers, is composed of entangled short fibers, and is 1 ounce / square yard (=
It is a non-woven fabric having a tensile strength of 1 pound per inch (178.6 g / cm 2) or more per unit weight of 33.9 g / m ² .

Since the above-mentioned artificial leather base fabric has an elongation recovery rate of 70% or more, the dimensional stability of the treated fabric is extremely good.

Here, the elongation recovery rate is measured by the following method.

That is, 3 or more 5 cm x 30 cm test pieces are sampled in the vertical and horizontal directions, a part of the test piece is fixed with an upper clamp using a tensile tester, and the other end is subjected to an initial load (the sample does not elongate). Apply a load such that there are no unnatural wrinkles), mark at 20 cm intervals, gently apply a load of 500 gf (gram weight), leave for 1 hour, and measure the length between marks.
Then, the weight is removed, an initial load is applied one hour later, the length between the marks is measured again, and the elongation recovery rate (%) is calculated by the following formula, and is represented by an average value of three or more times.

Elongation recovery rate (%) = (L ₁ −L ′ ₁ ) / (L ₁ −L ₀ ) × 100 where L ₀ : Length of original mark (20 cm) L ₁ : 500 gf load for 1 hour Length between marks after application (cm) L ′ ₁ : Length between marks after initial load 1 hour after unloading (cm) Normally, to remove urethane resin from the treated cloth, After being immersed in DMF at room temperature and allowed to stand for one day and night, the operation of renewing DMF can be repeated three times to completely remove it.

By removing urethane resin and other deposits,
The distinction between the non-woven fabric forming the present invention and other non-woven fabrics is obvious.

For example, the binder nonwoven fabric is extremely unstable in shape and easily cut by removing the binder, and the presence of long fibers is clearly confirmed in the long fiber nonwoven fabric. A short fiber non-woven fabric having a fused portion by a fused fiber, a so-called melt blown type non-woven fabric is difficult to distinguish from the spunlaced fabric of the present invention, but when observed in an enlarged manner, no entanglement of the fibers is observed, There are scattered spots.

Example 1 Polyester short fiber 1.3 denier, cut length 22 m
m spunlace nonwoven fabric, basis weight 38 g / m ² , thickness 0.36 mm, is padded with a urethane resin emulsion having 100% elongation stress of 20 Kg / cm ² as film characteristics (JIS K6301), dried, fiber weight Against 7
Base fabric for artificial leather with a urethane resin content of 4%
1 g / m ² ) was obtained.

As a comparative test, the same treatment was performed using a urethane resin having a stress at 100% elongation of 53 Kg / cm ² . The results of elongation recovery rate and bending resistance are shown in Table 1.

The bending resistance is measured by JIS L1096 bending resistance E method (handle odometer method).

From the above results, it can be seen that the spunlace cloth treated with the urethane resin having a stress at 100% elongation of 53 kg / cm ² becomes extremely hard and has extremely low elasticity.

Further, the operation of immersing the urethane-treated cloth in DMF at room temperature for 24 hours, discarding the DMF from which the urethane resin was extracted, and renewing the DMF again was repeated 3 times, and the attached urethane resin was completely extracted and removed. This was confirmed by the change in weight. The measurement results of the tensile strength after the original cloth and after extraction and removal are shown in Table 2.

Vinyl chloride resin was coated on this base cloth impregnated with urethane resin by a calendar method to obtain a non-foaming type PVC leather. There was no problem in width shrinkage during coating and other process processability.

The most commonly used as a base fabric for PVC leather, Sufmusulin 4 (weight: 72g) (30s of staple fiber, 90 stitches per square inch, texture plain weave), PVC coated under the same conditions as above, and the same A thick PVC leather was obtained. The physical properties of both are shown in Table 3.

However, in the above, the breaking strength and breaking elongation are based on the tensile test JIS k6772. The tear strength is JIS k
6772 By single tongue method. Furthermore, the peel strength is JI
According to S k6772.

From the above measured values, when using the base fabric according to the present invention,
The strength is not inferior to that of the conventional moth base fabric, and the fact that it is integrated as a leather can be seen by looking at the peel strength measurement results of the PVC layer and the base fabric. However, the elongation rate is large (the recovery to the initial elongation is good), and in this respect, it has a characteristic closer to that of a knitted base fabric than that of a woven fabric-based leather. In addition,
Although not shown in the data in Table 3, the urethane-treated cloth according to the present invention is extremely flexible as compared with the use of the sfumosulin base cloth, and this point is the greatest feature as a product.

Example 2 Polyester short fiber 1.3 denier, cut length 22 m
m, rayon short fiber 2 denier, cut length 29 m
Spunlace nonwoven fabric composed of 70% of m and 30% of 30%, and a weight of 68 g / m ² of 0.56 m
m. Film characteristics (JIS K6301) are soaked in a DMF solution of urethane resin having a stress of 100% elongation 21 kg / cm ² , squeezed with a mangle, and treated in water for 2 minutes.
By extracting MF, the urethane resin is solidified,
Subsequently, it was treated in warm water at 50 ° C. for 3 minutes to sufficiently remove DMF, then squeezed with a mangle and dried with hot air. By this wet-type urethane treatment, a base fabric for leather (weight per unit area: 109 g / m ² ) impregnated with 61% urethane resin based on the weight of fiber was obtained.

Table 4 shows the measurement results of the elongation recovery rate before and after the urethane treatment.

Further, this urethane-treated cloth was immersed in DMF at room temperature for 24 hours, the DMF from which the urethane resin had been extracted was discarded, and the operation of renewing was repeated 3 times, and the adhered urethane resin was completely extracted and removed. Was confirmed by weight change.

The results of measurement of the tensile strength after the raw cloth and after extraction are shown in Table 5.

Using this base cloth as a base, urethane coating by a wet method and urethane film lamination by a transfer method were performed. In each process, there was no problem in width shrinkage and other workability, and a high-quality urethane leather having flexibility and a sense of unity was obtained.

{Effect} Since the present invention has the above configuration, it has the following effects.
That is, unlike artificial leather using a conventional woven or knitted fabric as a base fabric, the thread does not fray from the cut end, the resin layer and the base fabric have a sense of unity, and further, the spunlaced fabric of the present invention. Since it does not have an adhesive portion formed by a binder or a molten fiber, the constituent fibers are slid by bending and stretching, the positions of the constituent fibers move, the fibers have flexibility, and the elongation recovery rate is 70%.
%, The dimensional stability is good, and it is possible to provide a high-quality artificial leather base fabric without the problem of width control during coating (or laminating) and the anisotropy problem of leather products.

Claims (4)

[Claims] 1. A base fabric for artificial leather, in which a specific resin is applied to a base fabric to obtain artificial leather, and the base fabric is entangled with short fibers. A base fabric for artificial leather, which is formed by impregnating a nonwoven fabric with a urethane resin, and the base fabric has an elongation recovery rate of 70% or more. 2. The non-woven fabric is 1 ounce / min when the urethane resin impregnated in the artificial leather base fabric is removed.
The base fabric for artificial leather according to claim 1, which has a tensile strength of 1 pound or more per inch per square yard weight. 3. The urethane resin has a film characteristic of 10
The base fabric for artificial leather according to claim 1 or ^{2, wherein the} stress at 0% elongation is 25 kg / cm ² or less. 4. A method for producing a base fabric for artificial leather, in which a specific resin is applied to a base fabric to give artificial leather, and the fibers are entangled with each other,
Characterized by impregnating a non-woven fabric having a tensile strength of 1 pound or more per inch per unit area of 1 ounce / square yard with a urethane resin having a film property of 100 kg elongation at a stress of 25 kg / cm ² or less. A method for manufacturing a base fabric for artificial leather.