JPH01201586A - Synthetic leather and production thereof - Google Patents

Abstract

PURPOSE:To obtain a synthetic leather with both appearance and feel similar to those of natural leather, by forming a polyurethane fine porous layer on a base fabric (pref. coarsely raised) consisting of knitted woven fabric compris ing extremely fine single fibers and by further forming, pref. a polyurethane film on said layer. CONSTITUTION:A base fabric consisting of a knitted woven fabric comprising of single fibers of 1-0.01 deniers is impregnated with an aqueous solution containing a penetrant (an anionic surfactant) and polyurethane solvent. The surface of the resultant fabric is pref. brought into contact with a hot roll surface (in order to form a surface layer free from pinholes or depression holes) followed by coating said surface with a polyurethane solution and then solidifying the polyurethane to form a polyurethane fine porous layer. Said layer is then pref. conjugated with a release paper with a polyurethane film formed thereon into unity, thus obtaining the objective synthetic leather excellent in smoothness close to natural leather. Coarse raising of said knitted woven fabric will increase the bond strength between said fine porous layer and the base fabric.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to synthetic leather and a method for producing the same.

[Prior Art and Problems to be Solved by the Invention] Synthetic leather, which is made by forming an elastic resin layer such as polyurethane on the surface of knitted or woven fabric, has recently been widely used for various purposes. Conventionally, this type of synthetic leather has used a knitted fabric made of a single fiber of about 1.5 d as a base fabric, but there has been a problem that it still lacks a soft texture.

On the other hand, among the manufacturing methods of this type of synthetic leather, the wet method involves applying a solution of polyurethane in dimethylformamide (DMF) to the base fabric, and then immersing it in an aqueous solvent to coagulate the polyurethane on the surface of the base fabric. Known methods for forming a polyurethane resin layer include a dry coating method in which a polyurethane solution is applied directly to a base fabric, and a wet coating method in which a polyurethane solution is applied after impregnating the base fabric with water. In the wet coating method, the base fabric is pre-impregnated with water, which is a non-solvent for polyurethane, so there is no problem of the applied polyurethane solution penetrating to the back side of the base fabric, and unlike the dry coating method, the polyurethane solution It is not necessary to perform treatment with a water repellent agent to prevent excessive penetration into the base fabric, and problems such as insufficient adhesive strength between the base fabric and the polyurethane layer caused by treatment with a water repellent agent can be resolved. There are also various problems caused by dipping the base fabric in water to impregnate the base fabric with water.

That is, the fineness of single fibers conventionally used as base fabrics is 1.
Instead of a knitted fabric made of fibers of about 5d, single fiber fineness 1
．． Even if an attempt is made to obtain a more flexible texture by using a knitted fabric made of fine denier yarn with Qd or less, such fine denier knitted fabric has a very high fiber density, so when the base fabric is immersed in water, It is difficult to completely replace the air in the base fabric with water. During the process of applying the polyurethane solution and wet coagulating, the air remaining in this base fabric migrates into the polyurethane coating layer and comes out, resulting in numerous pinholes on the surface of the formed microporous polyurethane layer. There's a problem. In addition, if the base fabric is coarsely brushed to increase the adhesive strength between the polyurethane microporous layer and the base fabric, the water impregnated in the base fabric will be sucked up by the capillary action of the nap, forming water droplets at the tips of the naps. When a polyurethane solution is applied to the surface of the base fabric, which has water droplets at the tip of the nap, the water droplets at the tip of the nap cause the polyurethane to coagulate locally.
As a result, there is a problem in that many sinkholes occur on the surface of the formed microporous polyurethane layer, and when pinholes and sinkholes occur on the surface, the aesthetic appearance of the surface deteriorates even if a skin layer is provided on top. In view of the above points, the inventors of the present invention have conducted intensive research and found that when a textile fabric made of fibers of 1.0 d or less is used as a base fabric, the penetrant and polyurethane solvent can be obtained. By immersing the base fabric in an aqueous solution in which the base fabric is dissolved, the air in the base fabric can be almost completely expelled, and synthetic leather having a pinhole-free polyurethane microporous layer on the surface can be produced. It has been found that the obtained synthetic leather has an extremely soft texture. 1. When using a roughly brushed knitted fabric made of fibers with Qd or less as a base fabric, the base fabric is immersed in an aqueous solution containing the same penetrant and polyurethane solvent as above, and then the surface of the base fabric is further coated. By bringing it into contact with the heating roll surface, the air in the base fabric can be completely replaced, and water droplets formed at the napping tip can also be effectively removed, forming a polyurethane microporous layer without pinholes or sinkholes. The inventors discovered that the synthetic leather thus obtained has an extremely soft texture and excellent physical properties such as high adhesive strength between the microporous polyurethane layer and the base fabric, and completed the present invention. It's arrived.

That is, the present invention is characterized by: +1) A base fabric made of a knitted fabric with a single fiber fineness of 1.0-0.01d, and a polyurethane microporous layer provided on one side of the base fabric. synthetic leather.

(2) It is characterized by consisting of a base fabric made of coarsely raised knitted fabric with a single fiber fineness of 1.0 to 0.01 d, and a polyurethane microporous layer provided on one side of the base fabric. synthetic leather.

(3) The synthetic leather according to claim 1 or 2, further comprising a polyurethane coating provided on the surface of the polyurethane microporous layer.

(4) A base fabric made of knitted fabric with a single fiber fineness of 1.0-0.01d is impregnated with an aqueous solution containing a penetrant and a polyurethane solvent, and then the polyurethane solution is applied to the surface of the base fabric, and then 2. The method for producing synthetic leather according to claim 1, wherein the polyurethane is coagulated by immersion in a non-solvent to form a microporous polyurethane layer.

(5) A base fabric made of roughly brushed knitted fabric with a single fiber fineness of 1.0 to 0.01 d is impregnated with an aqueous solution containing a penetrant and a polyurethane solvent, and then the surface of the base fabric is heated to the surface of a roll. 3. The synthetic leather according to claim 2, wherein a polyurethane solution is applied to the surface of the base fabric after contact with the base fabric, and then the polyurethane is coagulated by immersion in a non-solvent to form a polyurethane microporous layer. manufacturing method.

16) jt'-fiber m degree power 1.0~0.01 d
O) A base fabric made of 'rA woven fabric is impregnated with an aqueous solution in which a penetrant and a polyurethane solvent are dissolved, and then the polyurethane solution is applied to the surface of the base fabric, and then immersed in a non-solvent to coagulate the polyurethane, After forming the polyurethane microporous layer, a release paper on which a polyurethane coating is formed is placed on the surface of the polyurethane microporous layer so that the polyurethane microporous layer and the polyurethane coating are in contact with each other to join and integrate them. 4. The method for producing synthetic leather according to claim 3, further comprising the step of peeling off the release paper after tightening.

(7) Single fiber fineness is 1. At θ ~ 0.01 d, a base fabric made of roughly raised knitted or woven fabric is impregnated with an aqueous solution in which a penetrant and a polyurethane solvent are dissolved, and then the surface of the base fabric is brought into contact with the surface of a heating roll. After applying a polyurethane solution and then immersing it in a non-solvent to coagulate the polyurethane to form a polyurethane microporous layer, a release paper on which a polyurethane film has been formed is placed on the surface of the polyurethane microporous layer. 4. The method for producing synthetic leather according to claim 3, wherein the porous layer and the polyurethane coating are superimposed so as to be in contact with each other to bond and integrate them, and then the release paper is peeled off.

The main points are as follows.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows a longitudinal cross-sectional view of the synthetic leather according to claim 1 or 2, where 1 is a base fabric and 2 is a polyurethane microporous layer.

The base fabric 1 is made of a knitted fabric having a single fiber fineness of 1.0 to 0.01 d. Examples of the fibers constituting the base fabric 1 include synthetic fibers such as polyamide, polyester, and polyacrylic fibers, and modified fibers thereof. Polyurethanes such as polyester, polyether, polycaprolactone, and polycarbonate are used as the polyurethane constituting the microporous polyurethane layer 2, but they have appropriate stiffness and a flexible texture. In order to achieve this, it is preferable that the 100% modulus is 20 to 80 kg/cIa.

The thickness of the microporous layer 2 is 50 to 50 mm.

pm, especially preferably 100 to 500 μm, 5071
If it is less than m, the volume of the synthetic leather tends to be insufficient, and the texture of the base fabric tends to be exposed. Moreover, if it exceeds 1000 μm, the elasticity becomes strong and the flexibility, which is a characteristic of the base fabric made of fine denier fibers, is weakened.

FIG. 2 shows a synthetic leather according to claim 3, wherein a polyurethane coating 3 is further provided on the surface of the polyurethane microporous layer 2 of the synthetic leather shown in FIG. It is preferable to set it as IOμm. The polyurethane coating 3 may be formed of the same polyurethane as the polyurethane microporous layer 2, or may be formed of a different polyurethane.

Next, the method for producing synthetic leather of the present invention will be explained.

FIG. 3 shows a manufacturing method according to claim 4, in which the base fabric 1 is first immersed in a water impregnating tank 4 filled with an aqueous solution containing a penetrant and a polyurethane solvent, and then squeezed with a squeezing roll 5. After squeezing, the fabric is dipped into the treatment layer 4 again to impregnate the base fabric 1 with the aqueous solution.

Anionic and nonionic surfactants can be used as the penetrating agent for the aqueous solution in the treatment tank 4. Examples of the anionic surfactants include aerosol OT, dodecylbenzenesulfonate (e.g., sodium salt, etc.), and lauryl. Examples include sulfate ester salts, oleic acid butyl ester sulfates, alkylnaphthalene sulfonates, etc.
Examples of nonionic surfactants include nonylphenol alkylene oxide adducts, intermediate or higher alcohol alkylene oxide adducts, and the like.

The concentration of these penetrants in the aqueous solution is preferably 0.1 to 2% by weight; if it is less than 0.1% by weight, the water penetration effect is small, and if it is 2% by weight or more, there is little improvement in the effect. I can't hope. The polyurethane solvent in the aqueous solution is the same as the solvent for the polyurethane solution used in the next step, and DMF is usually used. The concentration of polyurethane solvent in aqueous solution is 5-7
0% by weight, especially 10-50% by weight is preferred. By adding a polyurethane solvent to the aqueous solution, the polyurethane solution in the next step will surely penetrate the surface of the base fabric.
If the base fabric contains water, it can prevent insufficient penetration of the polyurethane solution and reduce the adhesive strength between the base fabric and the microporous polyurethane layer, but if it is less than 5% by weight, the adhesive strength will not decrease. The effect is not sufficient, and if it exceeds 70% by weight, the texture becomes hard, which is not preferable.

The base fabric 1 treated with the treatment layer 4 is squeezed with a mangle 6 to adjust the amount of aqueous solution contained, and then a polyurethane solution (usually D
MF solution) is adjusted to a predetermined amount with a doctor knife 7 and then applied, and then immersed in a coagulation bath 8 filled with water or a non-solvent mainly composed of water to coagulate the polyurethane, thereby forming a polyurethane microporous layer. 2 is formed.

FIG. 4 shows a method for producing synthetic leather according to claim 5, in which the base fabric 1 has a single fiber fineness of 1.0 to 1.
A coarsely raised knitted or woven fabric with a diameter of 0.01 d is used. In this method, the base fabric 1 is immersed in a water impregnating treatment tank 4 similar to that described above, and then squeezed with a mangle 6 to adjust the amount of aqueous solution contained, and then brought into contact with the surface of a heating roll 9. By bringing the surface of the base fabric 1 into contact with the heating roll 9, water droplets generated at the tip of the nap are removed and smoothness is imparted to the surface of the base fabric, but the temperature of the heating roll 9 is 60°C or higher and 130°C. The following is preferable: If it is less than 60°C, water droplet removal and smoothness will not be sufficient, and if it exceeds 130°C, even the aqueous solution impregnated into the base fabric will be removed, and the base fabric will become dry and the polyurethane solution will Because it penetrates deep into the base fabric, the texture of the resulting synthetic leather becomes hard. For this reason, the temperature of the heating roll 9 is particularly 80 to 110°C.
It is preferable that After the base fabric 1 is treated with a heating roll 9, a polyurethane solution is adjusted to a predetermined amount using a doctor knife 7 and applied, and then immersed in a coagulation bath 8 similar to that described above to coagulate the polyurethane, thereby forming microporous polyurethane. A sexual layer 2 is formed.

The surface of the polyurethane microporous layer 2 formed in this manner may be subjected to surface treatment using a polyurethane surface treatment agent or the like, if necessary.

Further, as shown in FIG. 5, after a coating 3 is formed on the polyurethane microporous layer 2 by applying a polyurethane solution to a release paper 10, the microporous layer 2 and the polyurethane coating 3 are brought into contact with each other. It is also possible to form synthetic leather having a polyurethane coating 3 on the surface by bonding and integrating the two by means of overlapping, heat-pressing, etc., and then peeling off the release paper 10.

If necessary, it can be rubbed to make the texture even softer.

The kneading process can be carried out by circular, hand kneading in a tumbler, mechanical kneading, or the like.

The present invention will be explained in more detail by giving specific examples below.

Example 1 A double-sided coarsely raised woven fabric (thickness 0.25 am) made of polyester fibers with a single fiber fineness of 0.1 d was immersed in an aqueous solution containing 30% by weight of DMF and 0.5% by weight of sodium dodecylbenzenesulfonate. After impregnating the woven fabric with the aqueous solution, it was squeezed with a mangle (squeezing ratio of about 80%), and then brought into contact with the surface of a metal roll heated to a surface temperature of 100°C. This woven fabric has a 100% modulus of 30 kg/ca.
A polyurethane solution having the following composition containing 1 ml of polyester polyurethane was heated with a doctor knife to a depth of 0.8 ml.
After coating the polyurethane to a thickness of -, it was immersed in water at 20°C to coagulate the polyurethane. After dehydration, it was dried under hot air at 120°C to form a polyurethane microporous layer with a thickness of 0.5 mm and excellent smoothness without pinholes or sinkholes.

-Polyurethane r'? Polyurethane (manufactured by Dainippon Ink: Crisbon 8006HV)? Liquid (solid content 30% by weight)...100 parts by weight DMF...
......170 parts by weight anionic surfactant (
Made by Dainippon Ink 0@: Chris Bon Assister 5D-11) ......1.5 parts by weight Colorant (made by Dainippon Ink ■: Guirank TV Color)...5 parts by weight On the other hand, with aperture A polyester polyurethane (manufactured by Dainippon Ink ■: Crisbon NB-646) solution (containing 30 parts by weight of the same coloring agent as the above coloring agent) with a 100% modulus of 80 kg/cJ was applied onto release paper to a thickness of 7 μm. The polyurethane film was coated using a knife coater and dried with hot air at 90° C. for 2 minutes to form a polyurethane film. After superimposing the release paper on which the polyurethane coating was formed on the microporous layer of the woven fabric on which the polyurethane microporous layer was formed so that the polyurethane coating and the microporous layer were in contact with each other and bonding with heat,
The release paper was peeled off and the polyurethane coating was transferred to the surface of the microporous layer. The surface of this coating was treated with a polyurethane surface treatment agent containing a coloring agent of the same color as that added to the polyurethane coating using a gravure roll, and then rubbed in a circular machine at 100° C. for 20 minutes.

The resulting synthetic leather had a soft feel, flexibility, and drapability, retained its wrinkles after being rubbed over a long period of time, and had an excellent appearance and texture that closely resembled natural leather.

Example 2 Knitted fabric (
0.35 fin (thickness, no rough brushing), DMF 25% by weight,
Sodium alkylnaphthalene sulfonate 0.3% by weight
After impregnating the knitted fabric with the aqueous solution,
Squeezed using a mangle (squeezing rate approximately 80%). A polyurethane solution with the following composition containing polyester polyurethane with a 100% modulus of 45 kg/cnl was applied to this knitted fabric using a doctor knife, and the coating thickness was adjusted to 1.0 mm, and then the fabric was immersed in water at 20°C. to solidify the polyurethane. After dehydration, it was dried under hot air at 120°C to form a polyurethane microporous layer with a thickness of 0.65mm and excellent smoothness without pinholes or sinkholes.

Polyurethane solution set Polyurethane (manufactured by Dainichiseika: Rezamin CU4310HV) solution (solid content 26% by weight)...100 parts by weight DMF...
......160 parts by weight anionic surfactant (
Manufactured by Dainichiseika 01: Rezamin CUT-30)...
2 parts by weight nonionic surfactant (manufactured by Dainichiseika (+1: Rezamin CUT-190) 1 part by weight colorant (
(manufactured by Dainippon Ink ■: Dailac TV Color)...10 parts by weight Then, the surface of this microporous polyurethane layer was treated with a polyurethane surface treatment agent containing a coloring agent of the same color as the microporous polyurethane layer using a gravure roll. did.

The obtained synthetic leather had a soft and flexible feel and drapability, and had an excellent texture and appearance similar to natural leather.

Comparative Example 1 A woven fabric roughly brushed on both sides as in Example 1 was treated by immersion in an aqueous solution containing DMF and a penetrant, but was treated with polyurethane finely in the same manner as in Example 1 without treatment with a heating roll. A porous layer was formed.

A large number of sinkholes were present on the surface of this microporous layer.

After forming a polyurethane film on the surface of this microporous layer in the same manner as in Example 1, the surface of the film was treated with a polyurethane surface treatment agent, and was further rubbed in the same manner as in Example 1. Synthetic leather had many sunken holes on its surface, had a poor appearance, and could not be put to practical use.

Comparative Example 2 A microporous polyurethane layer was formed in the same manner as in Example 2, except that the same knitted fabric as in Example 2 was immersed in a treatment liquid containing no penetrant. Many pinholes were present on the surface of this microporous layer, and the appearance was poor and it could not be put to practical use.

〔Effect of the invention〕

As explained above, according to the present invention, the following effects can be obtained.

The synthetic leather of the present invention uses a knitted fabric made of fine denier yarn with a single fiber fineness of 1.0 to 0.01 d as the base fabric, so it has an improved soft texture compared to conventional ones, and has a natural texture. It has a texture very similar to leather. Further, when a roughly brushed base fabric is used, the adhesive strength between the microporous polyurethane layer and the base fabric is increased, and the peel resistance of the microporous polyurethane layer is greatly improved. Further, when a polyurethane coating is formed on the polyurethane microporous layer, the surface of the polyurethane microporous layer is protected, and by forming apertures etc. on the surface of the polyurethane coating layer, it has an excellent appearance similar to natural leather.

The method for producing synthetic leather of the present invention involves applying a polyurethane solution to a knitted fabric made of fine denier yarn of 1.0 to 0.01 d by a wet coating method, and then wet-coagulating it to form a polyurethane microporous layer. By using an aqueous solution that dissolves the polyurethane solvent and penetrant as the treated water in the process of immersing the base fabric in water,
Since the impregnation of the aqueous solution into the base fabric is excellent and the air in the base fabric is almost completely removed, there is a risk that pinholes may occur due to air remaining in the base fabric migrating to the polyurethane microporous layer. There is no. In addition, when using a coarsely raised knitted fabric as a base fabric, a method is adopted in which the surface of the base fabric is brought into contact with the surface of a heating roll after being immersed in an aqueous solution containing a penetrant and a polyurethane solvent. At the same time, the smoothness of the surface is improved, and it is possible to prevent the occurrence of sink holes on the surface of the polyurethane microporous layer caused by water droplets at the tip of the brushed hair. It is possible to obtain excellent synthetic leather with high adhesive strength.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 and 2 are longitudinal cross-sectional views showing different embodiments of the synthetic leather of the present invention, and FIG. FIG. 4 is a schematic diagram showing a method for manufacturing synthetic leather using a coarsely brushed base fabric; FIG. 5 is a longitudinal sectional view showing one manufacturing process of the synthetic leather in FIG. 3. . 1... Base fabric 2... Polyurethane microporous layer 3...
・Polyurethane coating 4...Water impregnation treatment tank 8...Coagulation bath 9...Heating roll 10...Release paper procedure manual (spontaneous) March 7, 1988 Patent application No. 1988 25325 No. 2, Name of the invention Synthetic leather and its manufacturing method 3゜Relationship with the amended case Patent applicant address 5 name, 22 Daikyo-cho, Shinjuku-ku, Tokyo (007)
) Achilles Co., Ltd. Representative Masao Oka 4, Agent 101-5, Voluntary amendment of the date of the amendment order (1) Page 11 of the specification, line 18, ``Impregnate with an aqueous solution.'' and line 19. "In the treatment tank 4...
・Insert the following sentence between ". "In addition, when the base fabric used in the present invention has stretchability, it is preferable to use a woven fabric with low stretch as an auxiliary material to temporarily adhere to the back side of the base fabric to facilitate manufacturing."

Claims (7)

[Claims] (1) Synthetic leather comprising a base fabric made of a knitted fabric with a single fiber fineness of 1.0 to 0.01 d, and a polyurethane microporous layer provided on one side of the base fabric. (2) It is characterized by consisting of a base fabric made of coarsely raised knitted fabric with a single fiber fineness of 1.0 to 0.01 d, and a polyurethane microporous layer provided on one side of the base fabric. synthetic leather. (3) The synthetic leather according to claim 1 or 2, further comprising a polyurethane coating on the surface of the polyurethane microporous layer. (4) A base fabric made of knitted fabric with a single fiber fineness of 1.0 to 0.01 d is impregnated with an aqueous solution containing a penetrant and a polyurethane solvent, and then the polyurethane solution is applied to the surface of the base fabric, and then 2. The method for producing synthetic leather according to claim 1, wherein the polyurethane is coagulated by immersion in a non-solvent to form a microporous polyurethane layer. (5) A base fabric made of roughly brushed knitted fabric with a single fiber fineness of 1.0 to 0.01 d is impregnated with an aqueous solution containing a penetrant and a polyurethane solvent, and then the surface of the base fabric is heated to the surface of a roll. 3. The synthetic leather according to claim 2, wherein a polyurethane solution is applied to the surface of the base fabric after contact with the base fabric, and then the polyurethane is coagulated by immersion in a non-solvent to form a polyurethane microporous layer. manufacturing method. (6) A base fabric made of knitted fabric with a single fiber fineness of 1.0 to 0.01 d is impregnated with an aqueous solution containing a penetrant and a polyurethane solvent, and then the polyurethane solution is applied to the surface of the base fabric, and then After solidifying the polyurethane by immersing it in a non-solvent to form a polyurethane microporous layer, a release paper with a polyurethane film formed thereon is placed on the surface of the polyurethane microporous layer so that the polyurethane microporous layer and the polyurethane film are separated. 4. The method for producing synthetic leather according to claim 3, wherein the two are joined and integrated by overlapping each other so as to be in contact with each other, and then the release paper is peeled off. (7) A base fabric made of coarsely brushed knitted fabric with a single fiber fineness of 1.0 to 0.01 d is impregnated with an aqueous solution containing a penetrant and a polyurethane solvent, and then the surface of the base fabric is heated to the surface of a roll. A polyurethane solution is applied to the surface of the base fabric, and then immersed in a non-solvent to coagulate the polyurethane to form a polyurethane microporous layer. 4. The method according to claim 3, wherein the release paper on which the film has been formed is superimposed on the polyurethane microporous layer and the polyurethane film so that they are in contact with each other to join and integrate them, and then the release paper is peeled off. Method of manufacturing synthetic leather.