JP2005171451A - Method for producing grain leather-like sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grain leather-like sheet having excellent surface texture and exhibiting excellent abrasion resistance even by using at a high curvature and provide a grain leather-like sheet suitable for the use having three-dimensional shape and large friction with hand such as a steering wheel cover. <P>SOLUTION: A coating layer composed of a polyurethane resin is formed on a fibrous substrate composed of ultrafine fibers and a polymer elastomer and the coating layer is coated with a solvent-type coating material containing a nitrocellulose derivative. Preferably, the ultrafine fiber has a fineness of 0.0001-0.2 dtex, the forming face of the coating layer is a sliced face obtained by slicing the fibrous substrate, and the polyurethane resin is a silicone-modified polycarbonate polyurethane. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a silvered leather-like sheet material, and more particularly, to a method for producing a leather-like sheet material having a silver surface on the surface, which is excellent in wear resistance even when used with a high curvature. .

  In recent years, as a substitute for natural leather, a leather-like sheet with a surface layer and an adhesive layer made of a polymer elastic body laminated on the surface of a fiber composite sheet has been characterized by its lightness, easy care, low price, etc. Widely used in fields.

  However, in a field that often comes into direct contact with human skin, such as balls and car handle covers, the texture is still not satisfactory. Further, when a leather-like sheet-like material is used, if the shape is three-dimensional and the curvature is large, there is a problem in that creases and wrinkles are likely to occur and wear proceeds from that portion.

  For example, Patent Document 1 discloses a synthetic leather having a skin made of a silicone-modified polycarbonate polyurethane resin on a fibrous base material made of knitted fabric. However, although this reduces friction, there is a problem that the single yarn fineness constituting the fibrous base material is large, and wrinkles are generated when bending with a high curvature, and wear occurs from that portion.

  Patent Document 2 discloses a leather-like sheet having a silicone-modified polyurethane cross-linked with a polyisocyanate-based curing agent on the skin. However, there is a problem that the surface becomes hard due to the cross-linking, resulting in poor flexibility and texture. It was.

Japanese Patent Laid-Open No. 9-31862 JP 2000-248472 A

  The present invention has been made against the background of the above-described prior art, and its purpose is to provide a silver-coated leather-like sheet-like material having excellent surface texture and excellent wear resistance even in a use state with a large curvature. is there.

  The method for producing a silver-finished leather-like sheet according to the present invention comprises forming a coating layer made of a polyurethane resin on a fibrous base material made of ultrafine fibers and a polymer elastic body, and then a solvent system containing a nitrocellulose derivative It is characterized by applying a paint.

  Further, the ultrafine fiber is obtained by extracting and removing one or more components from a mixed spun fiber composed of two or more kinds of polymer elastic bodies, or a coating layer of 0.0001 to 0.2 dtex. It is preferable that the polyurethane resin for forming the resin is a copolymer of silicone, the coating layer forming surface is a sliced surface obtained by slicing a fibrous base material, or the coating layer forming method is a laminate method. .

  According to the production method of the present invention, a silver-finished leather-like sheet-like material having excellent surface texture and excellent wear resistance even in a use state with a large curvature is provided.

Hereinafter, the present invention will be described in detail.
The production method of the present invention is a production method in which a coating layer made of a polyurethane resin is formed on a fibrous base material made of ultrafine fibers and a polymer elastic body, and then a solvent-based paint containing a nitrocellulose derivative is applied.

  As the fibrous base material composed of the ultrafine fibers and the polymer elastic body used in the present invention, conventionally known base materials for artificial leather and the like are used. Examples of fibers constituting the fibrous base material include polyamide fibers such as nylon-6, nylon-66, nylon-610, nylon-11, nylon-12, polyethylene terephthalate, polytriethylene terephthalate, polybutylene terephthalate, and the like. Examples thereof include polyester fibers such as copolymerized polyester as a main component, and several kinds of mixed fibers thereof. Among these, polyethylene terephthalate or nylon-6 is preferable from the viewpoints of production stability and cost. Further, these fibers need to be ultrafine fibers, and generally 0.0001 dtex to 0.2 dtex are generally used. From the balance between texture and strength, it is preferably 0.001 to 0.1 dtex. In the case of a fiber having a normal fineness that is not an ultrafine fiber, wrinkles tend to occur easily when bent at a high curvature, and the wear resistance at that portion tends to decrease.

  These fibers can be obtained by a known spinning method. In order to reduce the fineness, for example, a mixed spinning fiber, a sea-island spinning fiber, or a peeled split fiber manufacturing method can be applied. Furthermore, it is preferable that the fiber constituting the fibrous base material is obtained by extracting and removing one or more components from a mixed spun fiber composed of two or more kinds of polymer from the texture and physical properties, As such a multicomponent fiber, it is preferable that the island component is a polyamide such as nylon 6 or nylon 66, and the sea component is a sea island fiber such as polyethylene or polystyrene. When the sea component is polyethylene, the sea component can be extracted and removed with toluene.

  The fibers in the fibrous base material exist as a fiber aggregate, and examples of the fiber aggregate include conventionally known woven fabrics, knitted fabrics, nonwoven fabrics, etc., but improve the texture as a leather-like sheet. Therefore, it is preferable that the nonwoven fabric is mainly used, and the knitted or knitted fabric is partially included or not included for reinforcement. Furthermore, when the fibers of the fiber assembly are sea-island fibers, and the melting point of the sea component is lower than the melting point of the island component, it is preferable to heat-press the fiber assembly, increasing the surface smoothness of the resulting sheet-like material, The wrinkle at the time of bending can be made minute.

  Examples of the polymer elastic body that constitutes a part of the fibrous base material include SBR, NBR, polyurethane, polyester elastomer, and polyacrylate ester elastomer. Among these, polyurethane is preferable, and polycarbonate / polyether polyurethane is more preferable. For example, more specifically, it is a polycarbonate / polyether polyurethane elastomer obtained by reacting a polyalkylene carbonate diol having a molecular weight of 500 to 3000, a polyalkylene ether diol, an isocyanate, and a low molecular chain extender. In particular, the polymer elastic body is preferably porous in terms of texture, for example, dimethylformamide-soluble polyurethane for wet coagulation.

  The ratio of the ultrafine fiber to the polymer elastic body in the fibrous base material is preferably 15 to 50%, more preferably 30 to 40% of the polymer elastic body / fiber (hereinafter referred to as R / F).

  Any conventionally known method can be used to obtain such a fibrous base material. Particularly preferred is, for example, the following method. First, fibers that can be made ultrafine, such as sea-island type multicomponent fibers, are spun from a polymer composition of two or more components having different solvent solubility by a composite spinning method. This fiber is made into a non-woven fabric by means of a card, a cross wrapper, a needle locker or the like. Next, a sheet-like material can be obtained by impregnating a nonwoven fabric with a polymer elastic body such as polyurethane resin as an organic solvent solution such as dimethylformamide, dimethylacetamide, tetrahydrofuran, or an aqueous emulsion and coagulating the polyurethane resin.

  Here, the polyurethane resin can be solidified by any method such as a wet method in which a polyurethane resin is treated with a non-solvent liquid miscible with a solvent and a dry method in which the solvent is heated to evaporate. It is most preferable to employ a wet coagulation method in view of the performance of the obtained sheet. The sea component of sea-island fibers is dissolved and removed from the obtained sheet to create a composite sheet composed of ultrafine fibers and a polymer elastic body.

  Such a fibrous base material preferably has a thickness of 0.5 to 2 mm. It is also preferable to slice in the thickness direction in order to adjust the thickness.

  In the production method of the present invention, a coating layer made of a polyurethane resin is formed on a fibrous base material. Further, the surface on which the coating layer is formed is preferably a slice surface. When applied to the slice surface, the smoothness of the surface is high, so that the coating layer is also uniform, and the creases can be made minute and uniform. The polyurethane resin is obtained by reacting a polymer diol, polyisocyanate, and a low molecular chain extender, and the polyurethane resin of this coating layer is preferably a copolymer of silicone, The chain preferably has an organopolysiloxyl group at the middle or terminal. Further, a non-yellowing type polycarbonate-based polyurethane is preferable. It has excellent durability and flexibility as the surface of leather-like sheets.

  As a method for forming the coating layer, there is a wet coating method in which a resin is left on the surface when a fiber aggregate is impregnated with a polyurethane resin as a polymer elastic body when the fibrous base material is created, or a fibrous base material is used. Any conventionally known method such as a method of coating a polyurethane resin after forming can be used, but most preferably, an adhesive is applied on the fibrous base material or coating layer to cover the fibrous base material. This is a so-called laminating method in which the layers are laminated and dried. For example, it is a method obtained by forming a film of a coating layer on a release paper, applying an adhesive on the film, and laminating with a fibrous base material.

  Examples of the adhesive used in the laminating method include urethane-based and olefin-based adhesives, but urethane-based is most preferable, and is excellent in flexibility and wear resistance as well as adhesiveness. Among the urethane-based materials, polycarbonate-based polyurethane is preferable, and is excellent in durability and flexibility as the surface of the leather-like sheet-like material.

  In the production method of the present invention, it is essential to apply a solvent-based paint containing a nitrocellulose derivative on the surface side of the coating layer made of the polyurethane resin. The nitrocellulose derivative used in the present invention is derived from nitrocellulose obtained by nitrifying vegetable fiber, and those generally used as a coating agent can be employed. The preferred molecular weight of the cellulose derivative is about 500 to 300,000. As the resin component contained in the solvent-based paint together with the cellulose derivative, an acrylic resin or a polyurethane resin is preferable. Moreover, as a solvent used, the solvent which consists of 1 type, or 2 or more types of combinations chosen from alcohol, polyhydric alcohols, ketones, ester, carbonates, etc. is mentioned.

The solvent-based paint is preferably applied in the range of 5 to 50 g / m ^{2 by} wet. Moreover, it is preferable to apply | coat with the gravure roll which has a mesh the coating method. In the production method of the present invention, it is preferable to apply in the form of dots instead of the entire surface, and the leather-like sheet-like material tends to be soft and prevent the occurrence of large creases.

Hereinafter, the present invention will be described more specifically with reference to examples.
In addition, each item in an Example was measured with the following method.
(1) Abrasion resistance A circular handle having a handle radius of 17 cm and a gripping portion having a diameter of 17 mm, in which a leather-like sheet material to be measured is wound, is horizontally installed. Next, cut the cotton canvas (No. 6) to a width of 4 cm, hang it on the handle, attach a 1 kg weight to the end of the cotton canvas outside the handle, hold the inner end of the handle, stroke 10 cm, and speed 20 cycles / min. A wear test for 100,000 reciprocating motions was performed, and the surface condition of the test piece was evaluated by the following judgment.
Excellent: Gloss, no change in surface condition is observed Good: Gloss, surface condition slightly changed Possible: No wrinkle disappeared: Surface has peeled off

[Example 1]
Nylon 6 and low-density polyethylene were chip-blended at a compounding ratio of 50:50, and a sea-island mixed spun fiber having a fineness of 7.7 dtex and a fiber length of 51 mm was obtained by mixed spinning. The obtained sea-island fiber was made into a web by a card and a cross layer, and then needle punching was performed at a barb penetration punching number of 1000 / cm ² to prepare an entangled nonwoven fabric as a fiber aggregate of 630 g / m ² .

The entangled nonwoven fabric was preheated in a hot air oven at 160 ° C., and then pressed with a heating roll at 90 ° C. so that the apparent density was 0.29 g / cm ³ and the thickness was 2.1 mm.

  Next, the nitrogen content based on isocyanate obtained by reacting polyhexamethylene carbonate having a molecular weight of 1800 with polytetramethylene ether glycol having a molecular weight of 2050, 4,4′-diphenylmethane diisocyanate and ethylene glycol is 4.5%. The polyurethane elastomer dimethylformamide solution (concentration 15%) was impregnated into the pressed entangled nonwoven fabric, immersed in a 10% dimethylformamide aqueous solution, and wet coagulated. Thereafter, the substrate was thoroughly washed in warm water at 40 ° C. to obtain a polymer elastic material-impregnated base material having a fiber to polyurethane elastomer ratio of 75:25.

  Next, dip and nip were repeated on this substrate in toluene at 80 ° C. to dissolve and remove the polyethylene in the sea-island fibers, and the sea-island fibers were made ultrafine. Thereafter, toluene contained in the base material is removed in steam steam at 110 ° C., dried in a hot air dryer at 120 ° C., sliced in the plane direction, and divided into two pieces from the ultrafine fiber and the polymer elastic body. A 0.9 mm fibrous substrate was obtained. The average fineness of the obtained ultrafine fibers was 0.005 dtex.

Next, a silicone-modified non-yellowing polycarbonate polyurethane resin (Rezamin NES9950-3, manufactured by Dainichi Seika Co., Ltd., nonvolatile content 10 wt%) is applied twice on a release paper at a basis weight of 150 g / m ² and dried to form a coating layer. Furthermore, 150 g / m ^{2 of} a polyurethane resin (UD 8353, manufactured by Dainichi Seika Co., Ltd., nonvolatile content 40 wt%) to which a crosslinking agent and a crosslinking accelerator are added is applied and dried, and the above-mentioned sliced fibrous base material It was transferred to the sliced surface by a laminating method.

After aging for 48 hours, the release paper is separated, and then a solvent-based paint (corial mat lacquer NW, manufactured by BSF Japan Ltd.) containing a nitrocellulose derivative is applied to the outermost surface of the coating layer with a 110 mesh gravure roll. Then, drying was carried out to obtain a leather-like sheet-like material with silver. The coating amount with Wet was 15 g / m ² .

  When the obtained sheet-like material was subjected to a handle-shaped friction test, it was evaluated as “excellent”, and there was no large wrinkle when folded and it was excellent in touch.

[Comparative Example 1]
A sheet-like material was obtained in the same manner as in Example 1 except that the solvent-based paint containing the nitrocellulose derivative of Example 1 was not applied.

  Although the obtained sheet-like material did not have a large wrinkle when it was bent, it was evaluated as “impossible” when subjected to a handle-shaped friction test, and the touch also had a sticky sensation.

  The leather-like sheet-like material with a silver tone obtained by the production method of the present invention is excellent in wear resistance even when used at a high curvature, and has a high curvature such as a ball or a handlebar cover of an automobile. It can be particularly preferably used for applications where the hand touches.

Claims (7)

  Silver-coated leather-like sheet-like sheet characterized by forming a coating layer made of polyurethane resin on a fibrous base material made of ultrafine fibers and a polymer elastic body, and then applying a solvent-based paint containing a nitrocellulose derivative Manufacturing method.   The method for producing a silver-finished leather-like sheet-like material according to claim 1, wherein the ultrafine fiber is obtained by extracting and removing one or more components from a mixed spun fiber composed of two or more kinds of polymer elastic bodies.   The method for producing a grained leather-like sheet-like material according to claim 1 or 2, wherein the ultrafine fiber is 0.0001 to 0.2 dtex.   The method for producing a silver-finished leather-like sheet material according to any one of claims 1 to 3, wherein the polyurethane resin is a copolymer of silicone.   The method for producing a silver-finished leather-like sheet-like material according to any one of claims 1 to 4, wherein the surface on which the coating layer is formed is a sliced surface obtained by slicing a fibrous base material.   The method for producing a coated leather-like sheet material according to any one of claims 1 to 5, wherein the coating layer is formed by a laminating method. Method for producing a grain-finished leather-like sheet according to any one of claims 1 to 6, wherein the coating amount of solvent-based paints is 5 to 50 g / m ^2.