JPS616376A - Production of suede like artificial leather - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing suede-like artificial leather with excellent surface effects. More specifically, the present invention produces a corresponding change in tone on the surface when rubbed with a finger.

This invention relates to a method of manufacturing suede-like artificial leather with a so-called lighting effect.

BACKGROUND OF THE INVENTION Suede leather (5uede) has unique and excellent surface effects. Here, the surface effect refers to the writing effect, which is one of the surface characteristics unique to suede.
t) means that when you rub suede with your fingers, the fuzz on the surface turns in the direction of the rubbing, resulting in a different color from the surrounding area, resulting in a difference in tone. In order to produce such a lighting effect, the fibers must have a specific fineness and be 0.5 denier or less, and the density of the surface fluff must be high, and at the same time, the fluff must have a certain length. Appropriate spacing and voids must be formed between the fibers and the polymeric elastic material filled in the base fabric.

Conventional suede-like artificial leather is made by impregnating a nonwoven fabric with a polymeric elastic material and then buffing it without proper pretreatment, so the length of the fluff is inconsistent, the density of the raised pile is low, and it is not as elegant as natural suede. The reality is that it is difficult to obtain a product that is suitable for the market.

Special 1: The evaluation of suede products is greatly influenced by the nap, and its uses are often limited. To solve this problem, many leather researchers are conducting research from various aspects, such as surface processing methods for fiber polymer elastic materials. has been promoted.

For example, in U.S. Pat. No. 4,206,267, a nonwoven fabric is impregnated with a water-soluble polymer substance such as polyvinyl alcohol to fill it with a polymer-511i substance, and then the polyvinyl alcohol is removed again to form fibers. A void is formed between the polymer elastic bodies.

However, there is a possibility that the voids may not be sufficient, or that the fibers and the polymeric elastomer may continue to bond on the surface of the base fabric during the process. In addition, special public service No. 48-7700
Publication No. 1 discloses a method in which the surface of a sorted leather product is treated with an aqueous zinc chloride solution to appropriately embrittle the polymer elastic body and fibers to improve buffing properties. It cannot be ruled out that there is a possibility that the water permeates into the center of the fabric and significantly deteriorates the physical properties of the fabric.Also, in Japanese Patent Publication No. 55-32828, treatment is performed with a silicon compound before buffing; Although the texture is good, there are problems such as uneven napping.

Overview of the invention The inventors have discovered the physical properties of elastic polymers applied to artificial leather,
As a result of examining the distribution of polymeric elastic material filled in leather sheets, we found that surface writing
ng) We have completed a method for producing suede-like artificial leather with excellent effects.

Therefore, in order to eliminate the various drawbacks of the conventional fabric as described above, the present invention applies a pasting treatment to a nonwoven fabric under certain conditions, and then again concentrates a water-soluble polymer aqueous solution or dispersion on the surface of the base fabric. The object of the present invention is to provide a method for manufacturing suede-like artificial leather which has excellent surface effects by adding a polyurethane elastomer and buffing it after being filled with a polyurethane elastomer.

That is, in the present invention, a nonwoven fabric made of fibers with a fineness of 5 denier or less that can be made into ultra-fine fibers is subjected to a first sizing treatment using a water-soluble polymer as a sizing agent to form a base fabric, and then the nonwoven fabric is made into a water-soluble Concentrate the polymer aqueous solution or dispersion on the surface of the base fabric)
A suede-like material with excellent surface effect, characterized in that the second step of gluing treatment is carried out by applying 100% polyurethane, and then the water-soluble polymer is removed and buffing is carried out. This is a method for manufacturing artificial leather.

Details of the invention The detailed explanation is as follows.

In the present invention, a high-density nonwoven fabric is entirely formed using sea/island type fibers that can be divided into fineness of 0.5 denier or less in the final product, and then impregnated with a known water-soluble polymer such as polyvinyl alcohol. By again applying a solution or dispersion mainly composed of polyvinyl alcohol with a coatable viscosity to eliminate the possibility that the surface of the base fabric is filled with the polymeric elastic material. This is a method of producing suede-like artificial leather that has significantly improved subsequent puff ink properties and has an excellent surface writing effect.

Buffing property here refers to the piloerection effect caused by the buffing process, and has a concept that is directly connected to the lighting effect.

Needle punching (n
When a water-soluble polymer such as polyvinyl alcohol is impregnated into a nonwoven fabric (eedle punching), it then adheres to the fiber-to-fiber intertwining points and forms a binder (eedle punching).
nder) form stability or longevity in order for the effect to appear,
In addition, it forms voids between the fibers and polyurethane, softens the base fabric, and improves the buffing properties of the surface.
After that, when lowering the thin IJ & fibrosis vIJ, fibrils
Many effects are expected, such as improving the convergence of the b-port 1).

In the present invention, observations will be made only from the viewpoint of improving buffing properties for the purpose of the invention.

As shown in Figure 551, the cross section of the base fabric, which is a nonwoven fabric pasted with a water-soluble polymer, has a certain amount of heat at the fiber-to-fiber intertwining point +a) and at the surface of the fibers (1)). Well, glue has been applied. The thickness of this adhesive film layer is 5 - amount of adhesive applied,
Does it vary depending on the concentration, etc., or is it applied within the range of about 0.01 to 0.5μ?It is most suitable for the purpose of gluing and the subsequent desizing process, and when treated with polyvinyl alcohol, it is applied within the range of about 0.01 to 0.5μ.
A suitable surfactant suitable for the purpose, such as a penetrant, a surfactant, and a softener, is added to an aqueous solution of offflki%, and this is used as a treatment liquid for impregnation and padding, and the solids content is t'' for a heavy basket of fibers. It is most unfortunate that polyvinyl alcohol of 15 to 20% by weight gives (-1).

Next, a method of treating a water-soluble polymer after such glue fI and its effects will be described. When a monopolymer elastomer such as polyurethane is directly immersed into a base fabric pasted using an existing method, the polyurethane is filled in the thickness direction of the base fabric. As a result, the fibers and polyurethane coexist on the surface of the base fabric, and the fibers do not stand up to a certain good length in the subsequent huff ink process, and the polyurethane is not easily removed due to its own strength.

Therefore, the present inventors used a starched cloth (FIG. 2 c)
(d) in Figure 2 by applying a water-soluble polymer.
Glue: Add the agent to 1/2 of the thickness of the base fabric, preferably 1/2 of the thickness of the base fabric.
We devised a method to improve buffing properties by filling only the surface within 4 to eliminate the room for polyurethane to be filled. The gluing machine at this time was the first one as shown in Figure 3.
From the viewpoint of the physical properties of the leather, it is most preferable that the number of glued layers 1 of the first step and second step is between (e) and (f). Doing this will cause the polyurethane to embrittle, etc.
It is possible to produce suede-like artificial leather that has fiber strength and buffing properties in the range between (g) and (h) in FIG. 4 and has an excellent surface writing effect.

Here, the first and second stage glues f=1 treatment liquids must be water-soluble and high-temperature 1 or both must be usable or must not cause problems in the process. Therefore.

Primarily polyvinyl alcohol (IIVA), carboxyl methyl cellulose (c:Mc), starch, processed starch products, mixtures thereof, etc. may be prepared and used with appropriate additives.

According to the present invention, when padding,
Unless the resin is treated uniformly, severe unevenness may occur after drying, so special care must be taken. Even if a certain degree of damage occurs, there is no particular problem in the subsequent polyurethane dipping process, and this problem can be solved by heat setting (+1 cat-press) or the like. Heat setting can also be expected to have the additional effects of improving the fiber density on the surface of the nonwoven fabric1 and improving the puff ink properties after Ql.

When a non-woven fabric with a two-step adhesive is coated with polyurethane, the two-step adhesive surface layer or stay V
1-teel roll (5teel roll)
It is also better to let it pass through the lower part of the coagulation tank.

In the present invention, any fiber with a fineness of 5 denier or less is used as the fiber forming the nonwoven fabric.If the fiber has a fineness of 5 denier or less, it must have a fineness of 0.05 denier or less in the final product to have a good lighting effect, tactility J.3, wet touch (
Wet-touch (wet-touch)

These ultra-fine fibers are produced by simultaneously spinning fiber polymers in a special form into a continuous filament bundle with a certain denier, and then removing the bundle through a chemical and physical post-processing process. Then, the fiber item fineness is 05 denier,
This becomes the ultra-fine fibers at the bottom.

The types of fibers that can be used include polyester, polyamide, polyacrylonitrile, and other polymers that have fiber-forming ability.If fibers with high shrinkage and latent crimp properties are used, the density of the nonwoven fabric can be reduced. It is very effective in increasing

On the other hand, the molecular elastic materials that can be used in nonwoven fabrics include polyester polyurethane, polyether polyurethane, various polyurethanes such as polyester-polyether copolyurethane, various synthetic rubbers such as Nl5R, 110, and two types of these. A mixture of these and other materials is possible.In the present invention, polyester-polyether copolyurethane is most suitable, and fiber or polyester is more preferable.

To produce the nonwoven fabric used in the present invention, the fibers described above are processed into a cross-lapper,
random-1apper
f; It is possible to use a method such as manufacturing a web into a web and needle punching this web to three-dimensionally bond the web, or a paper making method, but it is better to use needle punching to run the fibers in the direction of the thickness. It is said to exhibit piloerection.

The IT value of a needle-punched belt varies depending on the application, but it is 150 to 3009/n? In terms of workability, it is also desirable that the external density be 0.18097 C- or higher, or at least 0.1509/r-L or higher.

In the present invention, the amount of water-soluble polymer applied depends on the type of treatment liquid,
Although it varies depending on the use and the condition of the nonwoven fabric, in order to obtain a uniform raised state and flexibility, it is preferable that the amount of glue on the entire nonwoven fabric and the amount on the surface of the nonwoven fabric is 10 to 40% by weight. (See Figure 3 6q) The amount of water-soluble polymer applied is
If less than this range, an effective binder (bin
der) If no effect occurs and there is a large amount, pressurize -
This comes with the problem of L.

In addition, the penetration depth of the water-soluble product molecules in the second stage may vary depending on the state of the glue (1/1/21J to 1/21J, based on the thickness of the base fabric) as described above. Below, especially 1/
Most preferably, it is 12 to 1/4 or less.

In order to achieve this, it is necessary to strictly control the concentration, especially the viscosity, of the processing liquid, but it is generally
It is better to use one with 00 P or more.

If the viscosity is too low, the treatment liquid will unnecessarily penetrate into the fabric.
-If it is too high, problems will arise such as it being coated on the surface as a complete film. The nonwoven fabric pasted in this manner is subjected to a known process (including polyurethane), then coagulated in water, washed, and heated to completely remove the water-soluble polymer treated as described above. . Water-soluble polymers such as polyvinyl alcohol can be completely desized by treatment with boiling water of 80℃ or higher for 30 minutes or more, but if the sizing agent is not completely removed, the leather sheet may become hard. There are some things you must keep in mind.

In addition, the ultra-fine fibers can be easily achieved by subjecting the fiber bundle to θ-dipping and padding in a solvent before or after the polyurethane impregnation process, and the leather top sheet produced in this way can be Surface treatment is done by buffing with a sander equipped with sandpaper.

This surface treatment is performed by first buffing with approximately 150 mt sandpaper, dyeing, and then re-buffing to smooth out the surface fuzz, thereby obtaining suede-like artificial leather with excellent lighting effects.

Effects of the Invention As shown in FIGS. 5 and 6, the artificial leather of the present invention thus obtained has a constant fluff length on the surface, a high surface fluff density, and a suitable bond between the fiber and polyurethane. The resulting voids create an enhanced lighting effect and a very soft texture.

Suede-like artificial leather has a wide range of applications, including clothing, interior decoration, footwear, and bags.

EXAMPLES Hereinafter, the method for producing suede-like artificial leather according to the method of the present invention will be explained in more detail with reference to Examples.

In this example, all percentages represent it%.

Example 1 Stable fibers of 3 d x 51 IIN in which polyethylene terephthalate ultrafine fibers were bundled with polystyrene were carded cloth wrapped and needle punched to obtain a nonwoven fabric weighing 200 g/〃〆. Apply 15% of the aqueous solution containing the product component to the fibers in terms of solid content, and then apply 1% of the PVA aqueous solution or dispersion again in the direction of the thickness of the base fabric.
Apply to the surface layer within 74. At this time, the viscosity of the solution is 1
There are 10 pages and a knife coater.
tcr), gravure coater (gravure co
atcr) etc. Next, tenter (tc
ter) and filled with a polyurethane elastomer by a known dipping method. Before and after this, the fibers were made ultrafine with toluene and buffed with sandpaper. After this, dye [Q] and use puff ink again to smooth out the fluff on the surface.
Comparative Example 1 For comparison, artificial leather was obtained by processing in the same manner as in Example 1, except that water-soluble component P was applied in two stages, that is, polyvinyl alcohol was not applied to the surface area. The physical properties are shown in Table 11ζ.

Example 2 A 4 d x 64 mm staple fiber in which polyethylene terephthalate ultrafine fibers were made into an ultrafine fiber bundle using nylon was punched with random wrapper ink to obtain a 25,097 m long nonwoven fabric. Then, using a PVA and CMC aqueous solution having a viscosity of 11" so that it can be reapplied, it was applied to the surface layer within 1/4 PJ in the 17th direction of the base fabric. The amount of glue applied in the first and second stages was 30% based on the fiber. The bundle was then filled with polyurethane, and 99% or more of the nylon was removed by repeatedly dipping the bundle in a solvent and padding. At this time, as a solvent, formic acid, hydrochloric acid, methanol/calcium chloride, etc. can be used, but an aqueous solution with good solubility is used. After that, I removed the glue and buffed it with sandpaper. Next, it was dyed with a disperse dye using a circular dyer, and then buffed again to obtain suede-laced artificial leather with an excellent surface lighting effect.

Example 3 A 20% polyvinyl alcohol aqueous solution was applied to the nonwoven fabric used in Example 1, and then a polyvinyl alcohol aqueous solution of an appropriate viscosity was applied to mainly the surface of the nonwoven fabric by a spraying method, dried, and then the surface was glued. The surface was smoothed by pressure bonding using a heat fixer at a temperature of 150°C. The obtained nonwoven fabric was processed in the same manner as in Example 1.

The bending resistance is determined by the cantilever method.

** The lighting effect is the result of a sensory test conducted by five leather engineers, and the higher the value, the better.

As mentioned above, the physical properties of the suede-like artificial leather produced by the method of the present invention are as shown in Table 1.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the nonwoven fabric with glue applied in the first stage, and the second stage
The figure is a schematic diagram of a nonwoven fabric that has undergone the second stage of sizing, Figure 3 is a graph showing the relationship between the amount of sizing applied, buffing properties and leather tensile strength, and Figure 4 is a graph showing the relationship between fiber strength and buffing properties. Graph showing the relationship; FIG. 5 is an electron microscope photograph of the surface of a product manufactured according to the present invention, and FIG. 6 is an electron microscope photograph of the side surface of a product manufactured according to the present invention.

Claims (1)

[Claims] 1. A nonwoven fabric made of fibers with a fineness of 5 denier or less that can be made into ultra-fine fibers is subjected to a first sizing treatment using a water-soluble polymer as a sizing agent to form a base fabric, and then made into a water-soluble fabric again. A second sizing treatment is performed by intensively applying an aqueous polymer solution or dispersion to the surface of the base fabric, and after filling with a polyurethane elastomer, the water-soluble polymer is removed and buffing is performed. A method for producing suede-like artificial leather with excellent surface effects. 2. The method of item 1 above, wherein the fiber is made of polyester or polyamide. 3. The method according to item 1 or 2 above, wherein the fineness of the ultrafine fiber is 0.001 to 0.5 denier. 4. The method according to item 1 above, wherein the sizing agent is polyvinyl alcohol, carboxymethylcellulose, starch, a processed starch product, polyacrylic acid, or a mixture thereof. 5. The method of item 1 or 4 above, in which the adhesive is applied by padding, coating, or spraying. 6. The method according to item 1 above, wherein the amount of glue applied in the second stage is in the range of 1/12 to 1/4 of the thickness of the base fabric in the thickness direction of the base fabric. 7. The method according to item 1 above, wherein the amount of sizing in the first stage and the second stage is 5 to 20% by weight in terms of solid content based on the fiber.