JP3142098B2 - Method for producing leather-like sheet material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a leather-like sheet having a tone of silver. Specifically, it is thick ground, has a fine crease pattern on the surface, and has high smoothness,
The present invention relates to a method for producing a leather-like sheet which is soft and has a texture similar to natural leather.

[0002]

2. Description of the Related Art As a method for producing a leather-like sheet having good surface smoothness, a thin film layer of polyurethane is applied to the surface of a fibrous base layer having a porous coating layer, and the surface is smoothed by flat embossing. Japanese Patent Publication No. 59-43586 proposes a method of applying a finishing layer, coloring and kneading. Japanese Patent Publication No. 49-40921 discloses a method of obtaining a leather-like sheet material having a smooth surface by bonding a silver surface layer comprising a fiber aggregate obtained by a papermaking method and a polymer elastic body to a fibrous substrate. Proposed. It is also known that the leather-like sheet is subjected to a relaxing treatment in warm water or a mechanical kneading treatment for the purpose of softening the sheet and imparting a crease pattern. In general, the texture of the folds obtained by the mechanical rubbing treatment is rough, and the folds with a fine texture can be easily obtained by the relaxing treatment in warm water.

[0003]

The leather-like sheet material is softened by performing a relaxation treatment in warm water,
You can get a finely textured crease. However, when trying to obtain a lightweight and soft leather-like sheet material with a thickness of 1 mm or more and relaxing the thick sheet material with a small apparent density, wrinkles due to fiber deformation due to the relaxation process occur. However, it was difficult to obtain a smooth surface with a fine texture. Increasing the amount of the impregnating resin to increase the apparent density of the sheet improves the surface smoothness, but increases the apparent density of the sheet, resulting in a heavy and hard-handed material. It is an object of the present invention to provide a method for producing a thick leather-like sheet having a soft texture, which has a finely textured crease on its surface and which has good smoothness.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a fiber assembly comprising ultrafine fibers and / or ultrafine fiber bundles and a polymer elastic polymer existing in the inter-fiber spaces having a thickness of 0.6 mm or less and an apparent thickness. On one surface of the fibrous base material layer 1 having a density of 0.40 g / cm ³ or less, a silver surface mainly composed of a high-molecular-weight elastic polymer was formed.
0.4m thick after relaxing in warm water of 0 ℃ or more
A method for producing a leather-like sheet, characterized by laminating with a fibrous base layer 2 having a thickness of not less than m and an apparent density of not more than 0.40 g / cm ³ .

[0005]

First, the fibrous base material layer 1 of the present invention is formed of a polymer aggregate comprising ultrafine fibers and / or ultrafine fiber bundles, preferably a polymer elastic weight in a space between fibers of a densely entangled three-dimensional entangled nonwoven fabric. It contains a resin mainly composed of coalescing. Here, the ultrafine fiber or ultrafine fiber bundle removes at least one component of a multicomponent fiber obtained by mixing or compound spinning at least two types of spinnable polymers having different solubilities and degradability with respect to a solvent or a decomposer. It is a fiber obtained by this. Polymers that can form such fibers include, for example, polyamides,
Examples include polyester, polyacrylonitrile, polyvinyl alcohol, polyolefins, regenerated cellulose, polyvinyl chloride, cellulose acetate, and polyether.

[0006] The multicomponent fiber is a fiber aggregate, preferably 3
Process into a three-dimensional entangled nonwoven fabric. That is, the short fibers of the multicomponent fibers are made into a card web, and after laminating a required number of sheets, the entanglement treatment is performed by needle punch or high-pressure fluid flow. The obtained entangled nonwoven fabric is subjected to a surface smoothing treatment by a flat calender treatment or the like before the resin impregnation as necessary. The multicomponent fibers are modified into ultrafine fibers and / or ultrafine fiber bundles after forming the fiber aggregate and prior to impregnation with the resin or after impregnating the resin. When denatured into ultrafine fibers before impregnation of the resin, it is preferable to provide a resin for temporary filling so that the ultrafine fiber bundle is not bundled by the impregnated resin.

[0007] The resin mainly composed of a high-molecular elastic polymer impregnated into the fiber assembly includes, for example, a polyurethane elastomer or a polyurethane urea elastomer composed of a soft segment and a hard segment, a synthetic rubber, an acrylate polymer, One or more polymer elastic polymers selected from these polymer elastic polymers such as copolymers and resins elasticized by using a plasticizer, such as polyvinyl chloride and polyamide. The polymer elastic polymer may be blended with an inelastic polymer, a filler such as an inorganic or organic substance, or a pigment as long as the elasticity is not impaired. These resins are used in the form of a solution or a dispersion or a mixture of a solution and a dispersion, and may contain a coagulation regulator, a foaming agent, other treating agents, a softener, a flame retardant, and the like.

As a method of impregnating the resin into the fiber assembly, a resin liquid is impregnated into the fiber assembly by a dipping method, a coating method, an indentation method or the like. Resin impregnated, wet method, dry method, etc.
Alternatively, a method of coagulating the resin into a porous or non-porous material by using these methods in combination is exemplified. A silver elastic layer is formed by applying a polymer elastic body to one surface of the fibrous base material layer 1 impregnated and solidified with a resin, and the surface on which the silver surface layer is to be applied is pressed against a heated smooth surface or a molding surface in advance. The surface of the sheet to which the silver layer is applied may be a smooth surface or a molding surface, or a solvent having an action of deforming the fibers or resin constituting the sheet may be applied to the sheet silver layer. After applying to the surface to be coated, it is preferable that the surface of the sheet to which the silver surface layer is to be applied is pressed as a smooth surface or a molding surface by pressing against a smooth surface or a molding surface (which may be heated). In this way, by making the surface of the sheet to which the silver layer is applied a smooth surface or a molding surface, various spots and irregularities existing on the surface of the sheet are corrected, and the sheet after the application of the silver surface layer The article can be of a natural leather-like nature.

The thickness of the fibrous base material layer 1 is 0.6 mm or less,
Preferably, the thickness is 0.3 to 0.5 mm and the apparent density is 0.4 g / cm ^3.
Hereinafter, it is preferably 0.2 to 0.4 g / cm ³ . If the thickness of the fibrous base material layer 1 is larger than 0.6 mm, the surface will be roughened and the surface will be roughened when a relaxation treatment is performed in warm water, so that sufficient smoothness cannot be obtained. . When the thickness is less than 0.3 mm, the strength is low, and the process is poor in processability, such as being easily damaged during the relaxation process. However, if the processability is ensured, it may be thinner. In order to make the thickness of the fibrous base layer 1 0.6 mm, the basis weight of the fiber assembly can be prepared so that the thickness becomes 0.6 mm from the beginning. Nonwoven fabrics generally have low strength, and thus have low processability. In addition, productivity is low because the line speed cannot be increased. For this reason, it is practical to produce a fibrous base material having a thickness twice or more as large as desired and slicing the fibrous base material into two to obtain a required fibrous base material layer 1.
When the slice is divided into two, the slice processing may be performed before or after the formation of the silver surface layer. The other fibrous substrate layer after slicing,
A grain surface layer can be formed as the fibrous base layer 1 or used as the fibrous base layer 2.

In the production of the leather-like sheet of the present invention, it is important that the apparent density of the fibrous base material layer 1 is 0.4 g / cm ³ or less. When the apparent density is more than 0.4 g / cm ³ , the weight of the obtained leather-like sheet increases, the texture becomes hard, and the balance when bonded to the fibrous base material layer 2 deteriorates. Further, the texture of the folds when the relaxing treatment is performed in warm water becomes rough, and the smoothness is poor. For this reason, natural leather-like softness,
A leather-like sheet material that satisfies all of the surface smoothness, the crimped form, and the lightness cannot be obtained. On the other hand, when the apparent density is 0.2 g / cm ³ or less, there are many voids, so that the shape stability and strength tend to be poor.

The apparent density of the fibrous base material layer 1 is impregnated into the fiber aggregate by changing the apparent density of the fiber aggregate before impregnating the resin with the entanglement conditions and the press smoothing treatment conditions. It can be suitably prepared by changing the amount of the resin, or by pressing after impregnating the resin. The ratio between the microfiber and the resin is not particularly limited, but when the amount of the resin is large, the texture is likely to be rubber-like, and when the amount of the resin is small, the fiber is liable to be swelled and has no swelling feeling. 80 / 20-40 / 60
Is preferably within the range.

On the surface of the fibrous base material layer 1 having a smooth surface,
A silver layer is formed by applying a resin mainly composed of a polymer elastic body. The resin to be applied may be porous or non-porous, but the thickness is preferably 100 μm or less. The grain surface layer may be a layer composed of a resin alone or a layer in which a resin and an ultrafine fiber are mixed and compounded. The silver surface layer is preferably formed of a plurality of layers from the viewpoints of adjusting the transparency of the appearance, adjusting the depth of the color tone, adjusting the fineness of the crease, and the scratch resistance. When the silver surface layer is a plurality of laminates, it is preferable to make the surface side layer thinner than the inner side layer, in order to obtain a favorable result in terms of surface performance, particularly, sensory performance. In particular, on the surface or near the surface,
The presence of a resin layer formed from an easily dyeable resin having a dye adsorption amount of at least 30 mg per 1 g of resin is preferred in terms of color tone in dye coloring. In addition, in a portion near the side in contact with the surface to which the silver surface layer is provided, a resin layer to which an additive having a hiding effect, for example, a pigment is added, means that the silver surface layer on the sheet is It is preferable because various spots on the surface to be provided can be hidden.

The silver surface layer can be formed by applying a resin solution or dispersion by a usual method such as a thin film transfer method, a gravure coating method, a roll coating method, a liquid surface contact method, and a knife coating method. A method of dry coagulation or wet coagulation is used, and a coagulation regulator, a filler, a pigment, and the like may be added to these resin solutions or dispersions. Also,
These silver surface layers may be composed of a plurality of layers having different formation methods. It is preferable that the resin liquid initially applied to the sheet has an appropriate viscosity or concentration so that the resin liquid does not excessively penetrate into the sheet. It is preferable to use a method that does not allow the resin liquid to permeate.

Examples of the resin mainly composed of a high-molecular elastic polymer forming the silver surface layer include the resins used for the above-mentioned resin-impregnated sheet. When the silver surface layer is formed of a plurality of resin layers, one or two layers of the outermost layer are a discontinuous film layer of an inelastic polymer, preferably a point-shaped layer having a small area. There may be.

A fibrous base material layer 1 having a silver surface layer formed on one side
Performs a relaxing treatment in warm water of 80 ° C. or more. The relaxation treatment can be performed using a normal dyeing device in a massage treatment in a warm water without tension, for example, using a Tyco dyeing machine, a Wins dyeing machine, a dash line dyeing machine, a circular dyeing machine, etc. The kneading treatment is carried out in hot water at 80 ° C. or higher, simultaneously with or independently of the dyeing treatment, and is an essential step in order to obtain the soft sheet material of the present invention. By this relaxing treatment, unique fine wrinkles are generated on the surface of the silver surface, and the fibrous base material layer 1 has a soft texture. In the case of the sliced product, it is preferable to apply a filling resin so that the sliced surface is not damaged by pilling or the like by the relaxation process.
In this case, if a resin soluble in a solvent for bonding with the fibrous base layer 2 is used, the resin for bonding with the fibrous base layer 2 can also be used.

A substrate layer 1 having a relaxed silver surface layer is bonded to a fibrous substrate layer 2 having a thickness of 0.6 mm or more and an apparent density of 0.4 g / cm ³ or less. As the fibrous base layer 2, it is preferable to use a sheet-like material containing a resin mainly composed of a polymer elastic body in an ultrafine fiber aggregate similar to the above-mentioned fibrous base layer 1. Fabrics such as woven, knitted, or nonwoven fabrics can be used. Examples of such a fabric include a woven fabric made of synthetic fiber or a spandex (elastic fiber), a knitted fabric such as tricot and knit, a nonwoven fabric made by a spun bond method and a melt blow method, and the like. It is important not to impair the soft texture while giving the object a sense of thickness. In addition, as a constituent fiber material, natural fibers such as cotton, hemp, wool, silk, rayon, acetate, nylon, acrylic, polyester, polyvinyl alcohol,
Examples include chemical fibers such as polypropylene, polyurethane, polyvinyl chloride, polyvinylidene chloride, and polyethylene, and blended yarns thereof. These fabrics may be impregnated with a resin mainly composed of a polymer elastic body. It is desirable that the resin-impregnated resin be softened by relaxing treatment in warm water or mechanical kneading as in the case of the fibrous base layer 1 having a silver surface.

The lamination of the sheet material having the relaxed silver surface layer and the fibrous base material layer 2 is performed by using an adhesive or by dissolving a part of the resin or fiber constituting each sheet with a common solvent. And glue. Examples of the adhesive include various synthetic resin systems such as urethane adhesives, acrylic, vinyl acetate, polyvinyl alcohol, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, chloroprene rubber, and nitrile rubber, and solvent-type synthetic rubbers. And an emulsion type adhesive can be used. In particular, the adhesive is preferably one having a high elongation rate, and the amount of the adhesive used is preferably in a range that does not reduce the texture and can ensure a sufficient adhesive force. 10-4
A guideline is about 0 g / m ² .

When a sheet impregnated with a resin is used as the fibrous base layer 2, the resin or fiber constituting each sheet is dissolved with a common solvent in order to obtain flexibility and a sense of unity after bonding. It is desirable to make them adhere. When it is necessary to increase the adhesive strength, a method in which a resin soluble in the common solvent is added to increase the adhesive strength, or a method in which a resin soluble in the common solvent is applied to the bonding surface in advance using a marking roll or the like. Is used. For example, when the resin constituting the sheet is a polyurethane elastomer, a polyurethane urea elastomer, an acrylonitrile-butadiene copolymer, or a polyacrylonitrile fiber, an acrylonitrile copolymer fiber or a vinyl chloride-based fiber mixed with the fiber constituting the sheet. In this case, N, N'-dimethylformamide (hereinafter referred to as DMF)
Or DMF in which polyurethane is dissolved.

The leather-like sheet of the present invention can be made into a leather-like sheet having a softer texture by treating it with a conventionally known softener. If necessary, a treatment with a water repellent, an antifouling agent, or the like can be used together.

[0020]

EXAMPLES The present invention will be described below with reference to more specific examples, but the present invention is not limited to these examples. The parts and percentages in the examples relate to weight unless otherwise specified.

Example 1, Comparative Example 1 100 parts of 6-nylon and 100 parts of polyethylene were mixed and spun, and then stretched, crimped and cut to prepare a 4dr raw cotton having 6-nylon as an island component. . A web was made from this raw cotton by a random weber and needle punched to make an entangled non-woven fabric of 430 g / m ² .
Then, the sheet was immersed in an aqueous solution of polyvinyl alcohol, dried, and then heat-treated at 135 ° C. to fuse polyethylene as a sea component to form a hard sheet. Thereafter, a 13% solution of polyurethane elastomer in DMF was impregnated with water 70%.
And 30 parts of DMF in a coagulation bath at 30 ° C. for wet coagulation. Subsequently, the sheet material was immersed in perchrene to extract polyethylene as a sea component, thereby obtaining a nonwoven fabric containing a porous polyurethane elastomer inside the entangled body of the ultrafine fiber bundle of 6-nylon. The coarse sheet had an apparent density of 0.35 g / cm ³ and a thickness of 1.0 mm.

On the surface of the coarse sheet, a 40% aqueous emulsion of polyether polyurethane (Vondic 131)
0: trade name, manufactured by Dainippon Ink and Chemicals, Inc.) was applied by gravure at a solid content of 16 g / m ² and dried. A 14% solution of a polyurethane elastomer containing 200% of a yellow-brown pigment with respect to the polyurethane elastomer (solvent; a mixed solution of ethylcellosolve-isopropyl alcohol-toluene) was applied thereon by a gravure method and dried to obtain 5 g. / M ² of a colored layer was formed. Further, silica having an average particle size of 40 μm for matting was added to a 7% solution (solvent; acetone-cyclohexanone-dimethylformamide mixed solution) of an easily dyeable polyurethane elastomer having polyethylene glycol as a soft segment, and the prepared composition solution was gravure. And applied to form a layer of 3 g / m ² . The resulting sheet had an appropriate gloss. A pattern similar to natural leather was imparted to this using a heated emboss roller.

This sheet material is sliced in the thickness direction and a fibrous base layer 1 having a silver surface layer and having a thickness of 0.5 mm and a thickness of 0.5
Thus, a fibrous base layer 2 having a thickness of 2 mm was obtained. Next, each of the fibrous base layers was subjected to a dyeing treatment at 85 to 95 ° C. for 1 hour in a dye aqueous solution obtained by mixing Irgaran Yellow 2RL, Irgaran Brown 2GL, and Irgaran Olive BGL, and further using a softener. A softening treatment was performed to obtain a brown-dyed sheet. Next, a 10% solution of polyurethane in DMF was applied to the slice surfaces of both fibrous base layers with a gravure roll having an indentation of 85 mesh to bond both sheets. The obtained leather-like sheet material had a thickness of 1 mm and a basis weight of 375.
g / m ^2, with a fine crease pattern different from the embossed pattern on the surface, with good smoothness and a sense of unity, with an appearance and texture similar to thick, soft leather. Was.

For comparison, the sheet after heating and embossing, which had been similarly dyed and softened without slicing, had a soft but large shrinkage wrinkle pattern on the surface during dyeing, and the silver surface Had poor smoothness and low commercial value.

Example 2 A single-filament fineness produced by a melt-blowing method by applying a urethane-based adhesive at a solid content of 30 g / m ² to the slice surface of the fibrous base material layer having a silver surface phase after the dyeing treatment of Example 1. But,
0.05 denier polypropylene fiber
A nonwoven fabric having a thickness of 5 mm and an apparent density of 0.16 g / cm ³ was bonded. Although the obtained leather-like sheet material had a thickness of 1 mm, the basis weight was extremely light at 310 g / m ^2.
The leather-like sheet-like material had a soft texture and good smoothness, and was similar to a soft, thick cowhide.

Comparative Examples 2 and 3 In Example 1, the basis weight of the entangled nonwoven fabric was 550 g / m ^2.
To obtain a coarse sheet having an apparent density of 0.46 g / cm ³ and a thickness of 1 mm. The surface of the coarse sheet was provided with the same silver surface layer as in Example 1, sliced in the thickness direction, divided into two parts, and dyed and softened under the same conditions as in Example 1. The sheet obtained by laminating both sheets after processing in the same manner as in Example 1
The surface smoothness was good, but the thickness was 1 mm and the basis weight was 48.
It was heavy at 5 g / m ² , and the texture was quite hard.
The sheet obtained by laminating the sheet having the treated silver surface layer obtained here and the fibrous base layer 2 of Example 2 has a thickness of 1 mm, a light weight of 365 g / m ² and a light surface. Although the smoothness was good, the texture was hard, and there was no sense of unity between the front side and the back side, and the balance was poor.

[0027]

According to the production method of the present invention, it is thick, having a thickness of 1 mm or more, light in weight, has high surface smoothness and has fine creases, and has a texture similar to that of thick soft leather. And a leather-like sheet having an appearance can be obtained.

Claims (1)

(57) [Claims] 1. A fiber aggregate comprising ultrafine fibers and / or ultrafine fiber bundles and a polymer elastic polymer present in the inter-fiber voids having a thickness of 0.6 mm or less and an apparent density of 0.40 g /
After forming a silver surface mainly composed of a high-molecular elastic polymer on one surface of the fibrous base material layer 1 having a thickness of not more than cm ³ and relaxing in warm water of 80 ° C. or more, a thickness of 0.4 mm or more and an apparent density of 0 .40
A method for producing a leather-like sheet, which is bonded to a fibrous base material layer 2 of g / cm ³ or less.