JPH0959700A - Inkjet drawing leather and leather products - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a leather for ink jet drawing which enables a fine distinct drawing, can be used for daily necessities and portable goods, and has improved softness and friction resistance by forming a water-base undercoating layer on a leather substrate and then a porous ink-accepting layer contg. alumina hydrate. SOLUTION: A natural leather, such as of the mammals, reptiles, or amphibia, tanned with chromium or tannin may be used as a substrate. An artificial or synthetic leather may be used, too. The substrate, selected according to the application, is coated with an undercoating agent comprising a coloring pigment, a water-sol. synthetic resin, casein, diluting water. etc., in a coating wt. (dry basis) of 10-60g/m<2> and then with a porous ink-accepting layer mainly comprising boehmite, i.e., alumina hydrate particles in the state of being bound with a binder, in a coating wt. of 2-60g/m<2> . On the ink-accepting layer are formed a layer for fixing an image drawn by an ink jet method and a transparent protective layer thereon.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leather-based inkjet drawing medium that enables formation of high quality images by an inkjet method, and a drawn leather product.

[0002]

2. Description of the Related Art Conventionally, an image is formed on a leather product by a method such as gravure printing, textile printing, roller printing, transfer, hand drawing, batik dyeing, tie dyeing, gradation coating, etc., but the process is complicated. It took a lot of manpower and time to finish the product. Further, these methods have problems in multicolor use, color matching work, definition and the like. In recent years, a means for adhering ink to a medium with high accuracy, such as an inkjet printer, has become widespread. However, when the ink is adhered to ordinary leather by such means, the ink easily diffuses and a clear and fine image cannot be obtained.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a flexible and abrasion-resistant leather-based ink-jet drawing medium which can be drawn finely and clearly, and which can be used as daily necessities for wearing and carrying. The purpose is to obtain a drawn leather product.

[0004]

DISCLOSURE OF THE INVENTION The present invention is for inkjet drawing having a water-based undercoat layer on a substrate made of a leather material, and further having a porous ink receiving layer containing an alumina hydrate thereon. Provide leather.

The present invention is also a porous ink-receiving layer having an aqueous primer layer on a substrate made of a leather material and further containing an alumina hydrate thereon, which is drawn by an ink jet method. Provided is a leather product having a layer on which an image is fixed and further having a translucent protective layer provided thereon.

BEST MODE FOR CARRYING OUT THE INVENTION

The leather material as a base material is not particularly limited,
Mammals such as cows, horses, pigs, sheep, kangaroos and deer, reptiles such as crocodile, lizard and snake, and natural leather such as amphibians. The tanning method of these natural leathers is mainly classified into two methods: chrome tanning and tannin tanning, and these tanning methods are selected depending on the application of the final product, and in the leather material used as the base material, It may be tanned by the method of. As the base leather material, artificial leather or synthetic leather such as polyurethane, polyvinyl chloride, or an aggregate of ultrafine polyester fibers can be used as well.

The finer the texture structure of the substrate and the smoother the surface, the finer and glossier the image can be obtained. However, even with a rough base material, an image that takes advantage of the characteristics of the base material can be obtained.
The type of leather base material can be appropriately selected according to the application such as footwear, bags, accessories, interiors, and clothing.

The water-based undercoating agent of the lower layer exerts a slight ink absorbing ability at the time of drawing and has an effect of preventing the ink from being absorbed and diffused in the leather layer, and at the same time, when it is used in the final product, it may be damaged by strong friction or impact. Even if the surface coating layer of the leather is destroyed, the exposed undercoating agent layer has a color similar to that of the drawing layer, so that it has an effect of not losing aesthetic value in appearance. In addition, it has adhesiveness to both the leather base material and the alumina hydrate layer that forms the ink receiving layer, and also sufficiently follows the expansion and contraction, bending and folding operations of the leather and the entry and exit of the sewing machine needle during sewing. Has the flexibility needed to

Examples of the material for the undercoating agent for the lower layer include color pigments such as titanium oxide, iron oxide, carbon black and silica, water-soluble synthetic resins, casein, acrylic copolymer emulsions, polyurethane emulsions, NBR (acrylonitrile-butadiene). Rubber) latex, SBR
(Styrene butadiene rubber) latex, additives, and mixtures thereof.

To apply the aqueous primer to a leather substrate,
Water is used as a diluent. The application means is selected according to the viscosity, the solid content concentration, the suction amount of the base material, the form,
It may be applied by any method such as air spray, airless spray, roll coating, curtain flow coating, knife coating, gravure coating, and hand coating. After coating, the primer layer is formed by drying.

The coating amount of the lower layer undercoating agent is 1 in terms of the nonvolatile content.
It is preferably in the range of 0 to 60 g / m ² . If the coating amount is less than 10 g / m ² , the adhesion of the surface layer to the layer containing alumina hydrate as a main component becomes insufficient, and the alumina hydrate surface layer on which an image is drawn is worn or worn. It becomes easy to peel off due to friction during use. Coating amount is 60g /
If it exceeds m ² , not only is the material consumed unnecessarily, but the flexibility of the substrate may be impaired, which is not preferable. A more preferable coating amount is 20 to 50 g / m ² .

The ink receiving layer containing alumina hydrate as a main component is preferably in a state in which alumina hydrate particles are bound by a binder. Specifically as the alumina hydrate, boehmite (Al ₂ O ₃ · nH ₂ O, n = 1 to 1
1.5) is preferred. The ink receiving layer had an average pore radius of 3 to 15 nm and a pore volume of 0.
It preferably has a pore structure of ^{3 to 1} cm ³ / g.

As the binder, starch and its modified products,
Organic polymer compounds such as polyvinyl alcohol and its modified products, SBR latex, NBR latex, carboxymethyl cellulose, hydroxyethyl cellulose and polyvinyl pyrrolidone can be used. The amount of the binder used is preferably 5 to 50% by weight of the alumina hydrate.
If the amount of the binder used is less than 5% by weight, the strength of the ink receiving layer containing alumina hydrate as a main component may be insufficient, which is not preferable. When the amount of the binder used exceeds 50% by weight, the absorptivity of the ink and the fixability of the dye may be insufficient, which is not preferable.

The ink receiving layer containing hydrated alumina as the main component preferably has a coating amount of ² to 60 g / m ² . If the coating amount is less than ² g / m ² , the fixability and absorptivity of the dye will be insufficient, and sharp and high color density drawing may not be possible, which is not preferable. Application amount is 6
When it exceeds 0 g / m ² , not only is the material unnecessarily consumed, but also the flexibility of the substrate may be impaired, which is not preferable. A more preferable coating amount is 4 to 30 g / m ² .

Means for providing an ink receiving layer containing an alumina hydrate as a main component on a substrate is, for example, an air spray, an airless spray, a coating solution obtained by adding a binder to an alumina hydrate, preferably alumina sol. It may be applied by any method such as roll coating, curtain flow coating, knife coating and gravure coating, and a drying method can be adopted. A porous protective layer may be provided on the alumina hydrate layer for the purpose of improving scratch resistance. It is desirable to use silica sol as the material of the protective layer.

An ink jet printer can be recorded on the leather surface. In an inkjet printer, it is preferable to record using an ink containing a water-soluble or a dye emulsified and dispersed in water as a coloring material.

Further, in a leather product obtained by drawing on the above-mentioned drawing leather by ink jet, when the light-transmitting protective layer is coated, the weather resistance and scratch resistance of the drawn object can be remarkably improved. Further, when a flexible resin is used for the protective layer, it is possible to sufficiently follow the expansion, contraction, bending and folding operations of the finished leather product when it is worn and carried, and the movement of the sewing machine needle during sewing.

The light-transmitting protective layer has adhesiveness to the alumina hydrate layer forming the ink receiving layer, and is capable of stretching and bending leather,
It has the flexibility necessary to sufficiently follow the folding operation and the movement of the sewing machine needle during sewing, etc., and at the same time it has a surface texture of leather due to strong friction and impact when the final product is worn or used while being carried. It is necessary to have sufficient impact resilience to protect the.

The light-transmitting property of the protective layer covering the surface of the drawing surface means that the protective layer is transparent or translucent, and an image formed on the alumina hydrate layer can be observed through the layer. The transparent protective layer may be colorless or colored. Furthermore, by adjusting the transparency and color of the coating layer or film layer forming the translucent protective layer, it is possible to adjust the glossiness and color of the surface of the finished product.

The light-transmitting protective layer is formed by applying a coating liquid capable of forming a light-transmitting protective film on the alumina hydrate porous layer after drawing to form a coating film, or by previously forming it. It can be formed by a method of laminating the transparent film.

When the translucent protective layer is formed by a coating method, the material thereof is nitrocellulose having a nitration degree of 10 to 20%, and cellulose acetate having a butylation degree of 30 to 40% and an acetylation degree of 10 to 20%. Examples thereof include butyrate, a cured product of a polyol (main agent) and an isocyanate (curing agent), a moisture-curable polyurethane, a vinyl chloride-vinyl acetate copolymer resin. If necessary, a plasticizer, a matting agent, an ultraviolet absorber, a transparent pigment and the like can be mixed and used in order to adjust the flexibility, gloss, weather resistance, discoloration resistance and the like of the coating layer.

In the case of urethane type materials, examples of the polyol include polyester polyol, polyether polyol and acrylic polyol. OH value is 40 ~
More preferred are 300 polyester polyols or polyether polyols. Examples of the isocyanate include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate and their derivatives. Hexamethylene diisocyanate, isophorone diisocyanate or their derivatives are more preferred. Moisture-curable polyurethane with NCO% of 3-7% and elongation of 50-
200% is preferable.

Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, butylbenzyl phthalate and tricresyl phosphate. Dioctyl phthalate and butylbenzyl phthalate are particularly preferable. As the matting agent, silica powder and polyethylene powder are preferable. As the solvent, it is preferable to blend an ester type, a ketone type, an alcohol type, an aromatic hydrocarbon type, or the like used in ordinary paints, in consideration of the dissolving power and the evaporation rate of the resin to be dissolved.

When a coating film is formed by using these materials as a coating solution using a solvent as a diluent, it is preferable to dissolve them in a plurality of solvents before use. In addition, the material that has no reactivity with water,
It is also possible to use those aqueous emulsions or dispersions diluted with water. When water is used as a diluent, as a water-soluble solvent used in a normal water-soluble paint, alcohol-based, ketone-based, glycol-based,
It is preferable to blend a glycol ether type, a glycol ester type or the like in consideration of the interfacial tension with the emulsifier or the dispersoid and the evaporation rate.

To apply the translucent protective layer to the leather substrate,
Water or solvent thinner is used depending on the vehicle component. The application means is viscosity, solid content concentration, suction amount of the base material,
It may be applied according to any form such as air spray, airless spray, roll coating, curtain flow coating, knife coating, gravure coating, and hand coating, and a drying method can be employed.

When laminating the film layer, an adhesive is used between the drawing surface and the film layer. The adhesive is appropriately selected mainly depending on the material of the film. The back surface of the film may be subjected to electrical discharge machining or the like to increase the adhesive strength. Examples of the material of the film include a fluororesin film, a urethane resin film, and an acrylic resin film.

The coating amount of the translucent protective layer is 5 to 100 g /
It is preferably in the range of m ² . The thickness of the film layer is preferably in the range of 5-100 μm. If the coating amount is less than 5 g / m ² or the thickness of the film layer is less than 5 μm, the functions as a surface coating and a protective film become insufficient, and the alumina hydrate ink receiving layer on which an image is drawn is not formed. , It becomes easy to come off due to friction during wearing and carrying. A coating amount of more than 100 g / m ² or a film layer thickness of more than 100 μm is not preferable because not only the material is unnecessarily consumed but also the flexibility of the substrate may be impaired. A more preferable coating amount is 10 to 85 g / m ² . The more preferable thickness of the film layer is 10 to 85 μm.

[0028]

【Example】

Example 1 (Transparent finish) As an aqueous undercoating agent, an aqueous casein-based coloring agent (Toupe Co., Ltd., trade name Color Paste White N) obtained by dispersing titanium oxide as a coloring pigment in an aqueous casein solution and fine silica powder are dispersed in an acrylic emulsion. The resulting resin dispersion (commercial name Compact Binder GT-R) and water were mixed at a ratio of 1: 3: 1 by weight to prepare an aqueous undercoating agent for the lower layer. This mixture has a nonvolatile content of 30%
It is. This aqueous undercoating agent was applied twice to cowhide kip using an air spray gun and dried. The coating amount was 48 g / m ² after drying.

As an alumina hydrate coating solution, boehmite sol (solid content concentration 18% by weight), polyvinyl alcohol (saponification degree 96.5%, 4% viscosity 65 cP) and succinic acid are 100: 6 by weight, respectively. The mixture was mixed at a ratio of 2 to prepare a coating liquid having a total solid content concentration of 15% by weight.
This alumina hydrate coating solution was applied on the undercoating agent-coated surface of cowhide using a bar coater and dried at 80 ° C. for 16 hours. The coating amount is 10 g / m as a dry standard adhesion amount
^{Was 2} .

The drawing leather produced by the above method was drawn with four colors of magenta, cyan, yellow and black using an ink jet printer.

The coating liquid for the coating layer for coating the surface is 1: 2 by weight of nitrocellulose paint and thinner, respectively.
At a rate of That is, a mixture of lacquer clear HG-2: lacquer thinner = 1: 2 manufactured by Toupe Co., Ltd. was prepared. The composition of the lacquer thinner is butyl acetate: methyl isobutyl ketone: toluene: butyl cellosolve = 3: 3: 3: 1 by weight. This mixture has a nonvolatile content of 11% by weight. This mixture was applied to the drawing surface of cowhide drawn by the above method using an air spray gun and dried. The coating amount after drying was 16 g / m ² .

Example 2 (Semi-transparent finish) After applying the lower layer to cowhide and applying alumina hydrate in the same manner as in Example 1, four colors of magenta, cyan, yellow and black were similarly used using an inkjet printer. It was drawn by. The coating liquid for the coating layer for coating the surface was prepared by mixing the nitrocellulose-based paint, the silica-containing nitrocellulose-based paint, and the lacquer thinner in a weight ratio of 1: 1: 4. That is, lacquer clear HG-2 manufactured by Toupe Co., Ltd .: mat clear O: lacquer thinner = 1: 1: 4 were mixed. This mixture has a nonvolatile content of 9%. The coating liquid of the coating layer for coating this surface was applied to the drawing surface of cowhide drawn using an inkjet printer using an air spray gun and dried. The coating amount after drying was 14 g / m ² .

Example 3 (Transparent Pigment Color Finish) After applying the lower layer to cowhide and applying alumina hydrate in the same manner as in Example 1, similarly using an inkjet printer, 4 of magenta, cyan, yellow and black were used. Drawing was done by color. The coating liquid for the coating layer for coating the surface was prepared by mixing the nitrocellulose-based coating material, the transparent pigment-containing nitrocellulose-based coating material and the lacquer thinner in a weight ratio of 1: 1: 4. That is, lacquer clear HG-2 manufactured by Toupe Co., Ltd .: coloring clear: lacquer thinner = 1: 1: 4 were mixed. This mixture has a nonvolatile content of 10%. The coating liquid of the coating layer for coating this surface was applied to the drawing surface of cowhide drawn using an inkjet printer using an air spray gun and dried. The coating amount after drying was 15 g / m ² .

Example 4 (Polyurethane finish) After applying the lower layer to cowhide and applying alumina hydrate in the same manner as in Example 1, four colors of magenta, cyan, yellow and black were similarly applied using an inkjet printer. I made a drawing. The coating liquid for the coating layer for coating the surface was prepared by mixing polyester polyol (main agent), isocyanate (curing agent) and thinner in a weight ratio of 2: 1: 1. That is, urethane # 30 clear BS manufactured by Toupe Co., Ltd .: Hardener A: Thinner = 2: 1: 1 were mixed. The nonvolatile content of this mixture is 42%. The coating solution for the coating layer that covers this surface is applied to the drawing surface of cowhide drawn using an inkjet printer using an air spray gun, and the temperature is 40 ° C. and the humidity is 60% R on a flat drying table.
It was dried at H for 48 hours. The applied amount after drying is 84 g / m.
^{Was 2} .

Example 5 (Comparative Example) An alumina hydrate coating solution was applied directly to cowhide in the same manner as in Example 1. Next, similarly, an inkjet printer was used to perform drawing with four colors of magenta, cyan, yellow, and black.

Evaluation The leathers of Examples 1 to 5 were evaluated as follows. The results are shown in Table 1. 1. Image quality: A high-definition photographic image having a wide range of hue and lightness was drawn, and the visual results were evaluated by the following 5-point method. 5: Very good image quality 4; Very good image quality 3; Good image quality 2; Somewhat good image quality 1; Poor image quality 2. Water resistance: Immersed in still water for 4 hours, and the degree of magenta bleeding was evaluated by the same 5 point method as above based on the results of visual observation.
Furthermore, the measurement results of the change in color density before and after immersion were expressed as relative values. 3. Adhesion: JIS K5400 8.5.2. According to the cross-cut tape method. The gap between the cuts is 2 mm. 4. Appearance of formed laminate: Visual observation was performed.

[0037]

[Table 1]

[0038]

According to the present invention, a clear image can be easily drawn on the surface of a leather substrate by using an ink jet printer,
It is also easy to output a large screen image. Furthermore, after drawing, by coating the surface with a coating layer or a film layer, the mechanical strength of the leather surface-forming laminate is increased,
It has the flexibility required to fully follow the expansion, contraction, bending, and folding operations, and the movement of sewing machine needles during sewing, and at the same time, it is resistant to strong friction and impact when the final product is worn or used while being carried. A leather product drawn by an inkjet printer is obtained which has sufficient impact resilience to protect the surface texture of the leather.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyoko Muta, et al. 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Co., Ltd. Central Research Laboratory

Claims (2)

[Claims] 1. An inkjet drawing leather having an aqueous undercoat layer on a base material made of a leather material, and further having thereon a porous ink receiving layer containing an alumina hydrate. 2. A porous ink-receiving layer having a water-based undercoat layer on a base material made of a leather material and further containing an alumina hydrate thereon, for fixing an image drawn by an inkjet method. A leather product having the above-mentioned layer, and further having a translucent protective layer provided thereon.