JPH08113800A - Method for treating natural leather with fluororesin and production of water-reprellent and oil-repellent leather - Google Patents

Abstract

PURPOSE: To provide a method for producing leather having effective water- repellent and oil-repellent properties and stain-preventing function, not causing color fading even under conditions of wetting by water and washing and not impairing touch feeling and not causing hardening. CONSTITUTION: Chromium-tanned leather having high chromium absorption content is dyed with a dye having a vinyl sulfone functional group or either one or both of different kinds of bifunctional type reactive dyes comprising monofluorotriazine and vinyl sulfone and then dyed with a phosphated dye. The dyed leather is subjected to fat-adding treatment with a fat adding agent obtained by solubilizing a mixture of a hydrophobic long-chain alcohol derivative ester with a high polymer into a high-boiling point polar solvent, together with a water soluble copolymer of acrylic acid and acrylamide used. The treated leather is subjected to sizing treatment with a fluororesin emulsion of a fluoroalkyl acrylate copolymer and dried and a fluororesin emulsion is blown onto the surface of the leather and the leather is subjected to heat curing treatment at a prescribed leather surface temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a fluororesin on the surface layer and surface of natural leather. Also,
The present invention is a method for producing water- and oil-repellent leather, more specifically,
The present invention relates to a method for producing a water-repellent and oil-repellent leather that retains the texture of natural leather even when wet or washed and does not lose color.

[0002]

BACKGROUND ART Natural leather such as cow leather, horse leather, pig leather, deer leather, sheep leather, goat leather, cambar leather, and reptile leather is used for shoes, bags, bags, belts, clothing, or for dresses and sports. It is used in a wide range of fields such as gloves.

When the raw material leather is to be used for these purposes, it usually undergoes the steps of preparatory work, tanning, dyeing, greasing and finishing. Chrome leather, which has undergone the preparation and chrome tanning steps, is made uniform in thickness and then enters the dyeing step.

In the conventional dyeing process, a direct dye, an acid dye, a basic dye, an alloy dye, a water-soluble sulfur dye or the like is used for dyeing.

In the fatliquoring step, natural or synthetic oils such as cod oil, whale oil, or leg foot oil are sulphated or sulphated, or various surfactants are added to emulsify them, which are then drum-treated to form the inside of leather. It was made to permeate into and keep the soft texture.

However, since these conventional dyeing and greasing methods include hydrophilic groups in the leather, the leather loses its color when wet, and the texture is impaired. I can't expect it. Regarding greasing agents, greasing agents and methods for imparting hydrophobicity such as lanolin and phosphorylated oils and other high molecular weight polymers have been developed recently, but they have not yet maintained a satisfactory soft texture.

By the way, the inventor of the present invention first disclosed in Japanese Patent Laid-Open No. 5-1
In Japanese Patent No. 79300, a long-chain dialkylsulfosuccinate is used as a main component, and a hydrophobic high-molecular polymer composed of a long-chain monoalkyl phosphate ester and a maleic anhydride-olefin copolymer is added to this as a high-boiling polar solvent diethylene glycol. It proposes a method for producing reptile leather including a greasing finishing step using a greasing agent emulsified with monobutyl ether. The publication proposes to perform a two-stage dyeing process in which a dye is first dyed with a vinyl sulfone-based reactive dye and then a phosphorylated dye is treated before the fatliquoring finish process.

By performing such treatment, the reptile leather can be processed so as to have excellent flexibility, washing resistance and slip resistance, but the water and oil repellency has not been sufficiently studied.

In addition, when used in sports applications, since water and oil repellency are particularly required, tanned leather which has been subjected to a greasing finish after ordinary dyeing is treated with a fluororesin. Since the conventional fluororesin processing impregnates or paints with an oil agent, it has the drawbacks of impairing the texture of natural leather and poor ventilation. In addition, the fluororesin processing of leather has a drawback that the texture is significantly impaired when heat-treated with an iron or the like, unlike the fluororesin processing of fibers.

In recent years, as a fluororesin processing method for improving such drawbacks, after a normal dyeing using an acid dye, a fluororesin compound which is capable of reacting in an aqueous system which does not require heat treatment and which has a low molecular weight is added, and a bath is added. Keep the temperature at about 50 ℃, 3
A method has been developed in which it is left for 0 minute to 1 hour, washed with water and dried.

In this way, the dyeing process and the greasing process are
It is closely related to the application of fluororesin in the subsequent finishing process, and even if it is treated with fluororesin for conventional dyeing, imparting water and oil repellency to leather and preventing stains, it is truly effective. Under the present circumstances, it is impossible to impart the functions of water repellency and oil repellency and stain resistance to leather.

[0012]

The object of the present invention is to improve the above-mentioned conventional dyeing method and introduce a new method which has never been used in the greasing method so that the color fading can be achieved even when wet or washed with water. No
A method for producing natural leather that has a highly water- and oil-repellent property and a stain-preventing function that also has high functionality without damaging the texture and becoming hard, and an inner layer of leather that does not impair the texture of the natural leather and It is an object of the present invention to provide a surface fluororesin processing method.

[0013]

In order to achieve the above object, the invention according to claim 1 is a method for processing a fluororesin of natural leather, wherein a fluororesin emulsion of fluoroalkyl acrylate copolymer is used. The chrome-tanned and greased leather having a high chromium adsorption is subjected to a sizing treatment, and after drying, a fluororesin emulsion of the fluoroalkyl acrylate copolymer is sprayed onto the leather surface, and then the surface temperature of the leather is increased. It is characterized in that the heat curing treatment is performed at 120 to 130 ° C.

Here, the invention of claim 2 is the same as claim 1.
In the method for processing a fluororesin of natural leather described above, the thermal curing treatment may be performed using far infrared rays.

The invention according to claim 3 is a method for producing water-repellent and oil-repellent leather, which comprises a dye having a vinyl sulfone functional group or monofluorotriazine with respect to a chrome-tanned leather having high chromium adsorption. After bottom dyeing with one or both of different bifunctional reactive dyes of vinyl sulphone, top dyeing with phosphorylated dye is carried out, and the dyed leather is treated with hydrophobic long chain alcohol derivative ester and high A greasing agent obtained by solubilizing a mixture of molecular polymers in a high-boiling polar solvent is subjected to a greasing step in which a copolymer of water-soluble acrylic acid and acrylamide is shared, and the surface and the surface layer of the greased leather are subjected. On the other hand, it is characterized in that it is treated with a fluoroalkyl acrylate copolymer, dried, and then treated with a fluororesin which is subjected to a heat curing treatment.

[0016] Here, the invention of claim 4 is the same as that of claim 3.
In the method for producing water-repellent and oil-repellent leather described above, the mixture is a mixture of a high-molecular polymer composed of a long-chain dialkylsulfosuccinate and a maleic anhydride-olefin copolymer, and the high boiling point. The polar solvent may be diethylene glycol monobutyl ether.

The invention according to claim 5 is the invention according to claim 3 or 4.
In the method for producing water-repellent and oil-repellent leather according to, the fluororesin processing is performed by using a fluororesin emulsion of fluoroalkyl acrylate copolymer, sizing treatment is performed on the inside of the greased leather, and after drying, After the fluororesin emulsion of fluoroalkyl acrylate copolymer was sprayed on the leather surface, the surface temperature of the leather was 120.
You may heat-cure so that it may become -130 degreeC.

According to a sixth aspect of the present invention, in the method for producing water-repellent and oil-repellent leather according to the fifth aspect, the thermal curing treatment may be performed using far infrared rays.

In the method for producing water-repellent and oil-repellent leather of the present invention, the tanning treatment is carried out after the usual preparation steps consisting of water immersion, lime immersion, deashing, enzyme treatment, bleaching and acid treatment. The step before the tanning treatment can be performed by any ordinary method.

The tanning treatment used in the present invention is a high chromium adsorption tanning treatment. The reason for performing high chromium adsorption tanning is to raise the heat shrinkage temperature of leather in water, improve the heat resistance and alkali resistance when dyeing with a reactive dye, and promote the binding of dye without impairing the texture of leather. . At the same time, it promotes the binding between the phosphoric acid group of the phosphorylated dye and chromium. Here, the chromium tanning with high chromium adsorption refers to a treatment in which the content of Cr ₂ O _{3 in} the leather after tanning is 3% or more.

In the dyeing process of the present invention, first, bottom dyeing is carried out under dyeing conditions applicable to leather with a vinyl sulfone functional type or a heterobifunctional reactive dye of monofluorotriazine and vinyl sulfone. These reactive dyes are strongly bound to leather-like functional groups through covalent bonds and exhibit high fastness permeation dyeing. After bottom dyeing, top dyeing is further performed with phosphorylated dye. Phosphorylated dyes are those obtained by modifying the hydroxyl groups of the dyes into phosphoric acid esters, which strongly bind to the chromium of chrome-tanned leather by a coordinate bond to achieve fast dyeing. Due to the different binding methods, it is possible to obtain a high-concentration dyeing with high fastness which cannot be obtained by using the reactive dye or the phosphorylated dye alone without impairing the texture of leather. In particular, if the reactive dye is used for leather under the same conditions as for fabrics and fibers, the leather quality will be impaired, the leather will harden, and the physical strength will remarkably decrease. In the case of dyeing leather, dyeing conditions must be adjusted. Further, in the dyeing of the phosphoric acid dye alone, in the permeation dyeing and the high density dyeing, a bond other than the coordination of the phosphoric acid group to chromium is generated, and the fastness is inevitably lowered. In order to apply both dyes, it is important to set the dyeing method under different conditions from those of woven fabrics and fibers, from the physical properties of leather.

In the fatliquoring step of the present invention, after dyeing, a fatliquoring agent obtained by solubilizing a long-chain alcohol derivative ester and a high-molecular polymer in a high-boiling polar solvent and a water-soluble acrylic acid-acrylamide copolymer are used. Is done. By using a water-soluble copolymer of acrylic acid and acrylamide, the washability of dyed and greased leather can be enhanced. Examples of the greasing agent used in the present invention include a greasing agent obtained by solubilizing a high-molecular polymer composed of a long-chain dialkylsulfosuccinate and maleic anhydride-olefin copolymer with diethylene glycol monobutyl ether. You can Penetrating such a fatliquoring agent inside the leather tissue,
At the same time, a drum treatment is performed using a water-soluble copolymer of acrylic acid and acrylamide, and then the carboxyl groups of the polymer are blocked by chroming, deposited, and dried.
By this greasing process, unlike the conventional method, it is possible to realize flexibility by evenly permeating the greasing agent, and since almost no hydrophilic groups remain in the leather, the texture is maintained even after wetting with water or after washing. It is possible to maintain and maintain leather without discoloration.

The fluororesin processing performed after the greasing step is
It is carried out by heat-treating a fluororesin emulsion containing an acrylic resin. Examples of the fluororesin used in the present invention include general formulas

[0024]

Embedded image

Examples thereof include those represented by
This fluororesin is a compound having a fluoroalkyl group composed of 3 to 20, preferably 6 to 12 carbon atoms, and specifically, does not contain a homopolymer of a vinyl monomer having a fluoroalkyl group or fluorine. Copolymer with vinyl monomer, polyester with monovalent or polyvalent alcohol having fluoroalkyl group and monovalent or polyvalent carboxylic acid with or without fluoroalkyl group, or monovalent or polyvalent alcohol and fluoroalkyl group Examples thereof include a polyester with a monovalent or polyvalent carboxylic acid, a monovalent or polyvalent alcohol having a fluoroalkyl group and a monovalent or polyvalent isocyanate, and an epoxy compound having a fluoroalkyl group.

Using the fluororesin emulsion, the surface layer of the natural leather is sized in a drum, and after drying,
The fluororesin emulsion can be sprayed on the leather surface and heat-treated so that the surface temperature of the leather is 120 to 130 ° C., whereby the fluororesin can be fused to the leather surface. It is difficult to heat-treat uniformly with an iron, a rod-shaped far-infrared lamp, hot air, etc., and far-infrared rays are irradiated through a panel-type ceramic filter in order to obtain a curing effect without damaging the texture of the leather surface as much as possible. This is preferable because the fluororesin can be fused under heating with a uniform temperature distribution. If the surface temperature of the leather is lower than 115 ° C, the binding between the fluororesin and the leather structure is not sufficient, and if it is higher than 135 ° C, the texture of the natural leather is impaired. Therefore, the temperature is preferably 120 to 130 ° C.

[0027]

EXAMPLES Examples of the present invention will be described in detail below.

Cowhide as raw leather was subjected to the usual preparatory steps of soaking in water, soaking in lime, deashing, enzyme treatment, bleaching and pickling.

Example 1 Using the leather that has undergone the series of preparatory steps described above, tanning treatment for high chromium adsorption was performed. That is, after shaving ordinary chrome tanned leather to adjust the thickness, in order to increase the heat shrinkage temperature in the liquid, the Cr ₂ O ₃ content of the leather is set to 3.5% or more so that the content is 40 to 45 ° C. Put the leather in the bath (40%: ratio of chrome liquid to the weight of leather), basicity 50%
The re-tanning was carried out by using 4% of the chromium liquid (containing 25% as Cr ₂ O ₃ ) based on the wet weight of the leather.

Then, bottom dyeing was carried out using a vinyl sulfone functional type reactive dye (Brill Blue B).

Dye solution Vinyl sulfone functional reactive dye 5.0% Na ₂ SO 4 5.0% Na ₂ CO ₃ 3.5% Na ₂ Al ₂ O ₃ 1.5% Dye solution and leather prepared in drum After putting in and druming for 30 minutes, 2% formic acid was added to neutralize and washed with water.

Further, top dyeing was performed with a phosphorylated dye (Blue # 1).

Dye solution Phosphorylated dye 1.5% The prepared dye and leather were put in a drum, and after drumming for 30 minutes, 2% formic acid was added to neutralize and washed with water.

After the above dyeing, a fatliquoring agent obtained by emulsifying a high-molecular polymer consisting of a long-chain dialkylsulfosuccinate and a maleic anhydride-olefin copolymer with diethylene glycol monobutyl ether, and water-soluble acrylic acid and acrylamide. A greasing finish was performed using the copolymer.

Fatty emulsifier Emulsion long-chain dialkylsulfosuccinate 6 parts by weight (carbon number 12-18) Maleic anhydride-olefin copolymer 6 parts by weight (olefin: carbon number 2-5) Diethylene glycol monobutyl ether 10 parts by weight Acrylic acid-acrylamide copolymer 8 parts by weight Water 2 parts by weight Add 30% of the fatliquoring emulsifier prepared to dyed leather to about 1
After drumming for an hour, it was dried. Finally, the surface layer of the leather is sized in a drum using a fluororesin emulsion (Teflon leather protector manufactured by DuPont), and after drying, the fluororesin emulsion is sprayed on the leather surface so that the surface temperature of the leather is 120 to 130 ° C. Far infrared rays through the panel type ceramic filter to about 30
It was irradiated for a second to fuse the fluororesin to the surface layer and the surface of the leather.

Example 2 The same leather as that used in Example 1 was subjected to a preparation process and subjected to chromium tanning treatment for adsorbing high chromium.

Next, a heterobifunctional reactive dye of monofluorotriazine and vinyl sulfone (Cibacron).
Bottom staining was performed using Blue C-R).

Dye solution 5.0% of monofluorotriazine and vinyl sulfone Heterodifunctional reactive dye Na ₂ SO ₄ 5.0% Na ₂ CO ₃ 3.5% Na ₂ Al ₂ O ₃ 1.5% Drum The prepared dye solution and leather were put therein, and after drumming for 90 minutes, 1% formic acid was added to neutralize and washed with water.

Further, top dyeing was performed with a phosphorylated dye (Blue # 1).

Dye Solution Phosphorylated Dye 1.5% The prepared dye solution and leather were placed in a drum and drummed for 30 minutes. Then, 1% formic acid was added to neutralize and wash with water.

After dyeing, a greasing finish and fluororesin processing were carried out in the same manner as in Example 1.

Example 3 Using the leather which has undergone the preparatory process, as in Example 1, chromium tanning treatment for high chromium adsorption, dyeing, and greasing finish were performed.
For the fluororesin processing, the same fluororesin emulsion (Teflon laser protector manufactured by DuPont) as in Example 1 was used, and the surface layer of the leather was sized in the drum using the fluororesin emulsion, and after drying, the emulsion was leather. Sprayed on the surface, the surface temperature of the leather is 120-130
Far-infrared rays from a rod-shaped far-infrared ray lamp were radiated through the ceramic filter for about 30 seconds so that the temperature became ℃, and the fluororesin was fused to the surface layer and the surface of the leather.

Example 4 Using the leather subjected to the preparatory steps as in Example 1, a high chromium tanning treatment was performed. Acid dye (acid blue black) with sulfonic acid soda base after tanning 5
Normal dyeing was carried out using%. The prepared dye solution and leather were placed in a drum, drummed for 1 hour, then neutralized by adding 1% formic acid, and washed with water.

Next, 10% of an emulsion prepared by emulsifying sulfated fish oil with a betaine derivative substituted with an alkyl group having 12 to 14 carbon atoms was added to the leather, drummed for about 1 hour, and then dried.

Thereafter, the same fluororesin processing as in Example 1 was performed.

Comparative Example 1 Using the leather that has undergone the preparatory process, chromium tanning treatment for high chromium adsorption, dyeing, and greasing finish were performed in the same manner as in Example 1.
For the fluororesin processing, the same fluororesin emulsion as in Example 1 (Teflon leather protector manufactured by DuPont) was used, and the surface layer of the natural leather was sized in the drum using the fluororesin emulsion, and after drying, the surface of the leather was dried. Far infrared rays were radiated through the panel-type ceramic filter for about 30 seconds so that the surface temperature of the leather was about 110 ° C., and the fluorinated resin was fused to the surface layer and the surface of the leather.

Comparative Example 2 Using the leather subjected to the preparatory process, as in Example 1, chrome tanning treatment for high chromium adsorption, dyeing, and greasing finish were performed.
For the fluororesin processing, the same fluororesin emulsion as in Example 1 (Teflon leather protector manufactured by DuPont) was used, and the surface layer of the natural leather was sized in the drum using the fluororesin emulsion, and after drying, the surface of the leather was dried. The leather was sprayed and set so that the surface temperature of the leather was about 135 ° C., and far infrared rays were irradiated through the panel-type ceramic filter for about 30 seconds to fuse the fluororesin to the surface layer and the surface of the leather.

Comparative Example 3 Using the leather subjected to the preparatory process, chromium tanning treatment, ordinary dyeing and greasing finish were carried out in the same manner as in Example 4. In the fluororesin processing, the same fluororesin emulsion (Teflon leather protector manufactured by DuPont) as in Example 1 was sprayed on the leather surface and heat-treated with an iron to fuse the fluororesin to the leather surface.

Using the leathers produced in Examples 1 to 4 and Comparative Examples 1 to 3, the texture, softness, water repellency, oil repellency, washability, dyeing fastness, tensile strength and tear strength were measured by the following measuring methods. It was measured. The measurement results are shown in Table 1.

[0050]

[Table 1]

Water repellency: Based on AATCC 22-1989, a water drop is dropped onto leather with a reagent (main component water) for a dedicated water repellency test, and the maximum is 100 and the minimum is 0 in consideration of roundness and penetration of the water drop. To do.

Oil repellency: Based on AATCC 22-1989, oil drops are dropped onto leather with a dedicated oil repellency test reagent (main component oil), and in consideration of roundness and penetration of oil drops, the highest grade, the lowest grade. Judge with 0.

Washability: After washing five times, JIS L
It measured according to 1005.

Dyeing fastness: Measured according to JIS 6086.

Tensile strength: Measured according to JIS K 6550.

Tear strength: Measured according to JIS K 6550.

[0057]

[Effects of the Invention] Today, natural leather is "leather-like"
Leather is required, and the demand for aniline leather that is not coated with paint is increasing.

On the other hand, conventional aniline leather, suede leather and nubuck leather, which are used in a wide range of fields such as shoes, bags, bags, belts, clothing and gloves for various purposes, are made of leather coated with paint and are easily wetted. However, there was a big drawback that it was easy to get dirty.

On the other hand, the present invention improves the above-mentioned drawbacks,
Water- and oil-repellent properties that are effective on leather without impairing the texture of leather, and the function of preventing stains. There is no discoloration or bleeding even when wet or washed that conventional leather does not have, and the texture does not become hard. It is possible to devise a method for manufacturing leather that also has a high-performance washable function, can be used in a wide range of applications, and can provide a leather material having the functionality demanded by many consumers today.

Claims (6)

[Claims] 1. A fluorinated resin emulsion of a fluoroalkyl acrylate copolymer is used to perform sizing treatment on the inside of tanned and greased leather with high chromium adsorption, and after drying, the fluoroalkyl acrylate copolymer is used. After spraying the fluororesin emulsion of 1. on the surface of the leather, the fluororesin processing method for natural leather is characterized in that the fluororesin emulsion is heat-cured so that the surface temperature of the leather is 120 to 130 ° C. 2. The method for processing a fluororesin of natural leather according to claim 1, wherein the thermal curing treatment is performed by using far infrared rays. 3. Chromium-tanned leather having high chromium adsorption is bottom dyed with either or both of a dye having a vinyl sulfone functional group or a heterobifunctional reactive dye of monofluorotriazine and vinyl sulfone. After that, top dyeing is further performed with a phosphoric acid dye, and the dyed leather is water-soluble with a fatliquoring agent obtained by solubilizing a mixture of a hydrophobic long-chain alcohol derivative ester and a high-molecular polymer in a high-boiling polar solvent. Is subjected to a greasing step in which a copolymer of acrylic acid and acrylamide is used in common, and the surface and the surface layer of the greased leather are treated with a fluoroalkyl acrylate copolymer, dried and then heat-cured. A method for producing water-repellent and oil-repellent leather, which comprises performing fluororesin processing. 4. The method for producing water-repellent and oil-repellent leather according to claim 3, wherein the mixture is a mixture of a long-chain dialkylsulfosuccinate and a high molecular weight polymer of maleic anhydride-olefin copolymer. And the high-boiling polar solvent is diethylene glycol monobutyl ether. 5. The method for producing water-repellent and oil-repellent leather according to claim 3 or 4, wherein the fluororesin processing uses a fluororesin emulsion of a fluoroalkyl acrylate copolymer, and the inside of the greased leather. Is subjected to a sizing treatment, dried, and then sprayed with a fluororesin emulsion of the fluoroalkyl acrylate copolymer onto the leather surface, and then heat-cured so that the surface temperature of the leather is 120 to 130 ° C. And a method for producing water- and oil-repellent leather. 6. The method for producing water- and oil-repellent leather according to claim 5, wherein the thermal curing treatment is performed using far infrared rays.