METHOD FOR MODIFYING ANIMAL HAIR

Abstract

An object of the present invention is to provide a modification method capable of affording animal hair having an anti-pilling property through simple treatment. The present invention provides a method for modifying animal hair, including a reduction treatment step of treating animal hair with a reduction treatment liquid containing a reducing agent under a neutral or weakly alkaline condition, and an enzyme treatment step of treating the animal hair subjected to the reduction treatment with an enzyme treatment liquid containing a water-soluble protein and a transglutaminase.

Description

TECHNICAL FIELD

The present invention relates to a method for modifying animal hair, in particular a modification method for preventing so-called pilling of animal hair, and animal hair obtained through modification treatment.

BACKGROUND ART

Products obtained from animal hair, such as wool, have drawbacks including occurrence of pills, which is called pilling. As prevention of pills (also expressed as “pilling prevention”), there may be taken a measure of reducing the strength of wool using a strong agent to remove pills and thereby reduce the amount of pills attaching to a processed product and pretend no generation of pills. However, weakening of wool reduces the thickness of the wool itself, affecting the texture of the wool itself. On the other hand, although there is a measure of inhibiting the generation of pills by coating wool with a resin agent, a touch peculiar to wool is lost due to the resin coating.

There have been treatments for preventing animal hair from pilling. For example, JP-A-3-213574 (Cited Literature 1) discloses that a cuticle part is crosslinked by treating animal hair fibers with an aqueous enzyme solution. The cuticle part is scaly existing outside the animal hair fibers, and it is known that this is a cause of pilling. Patent Literature 1 proposes that animal hair fibers are treated with an enzyme (including a transglutaminase) to prevent pilling. In this treatment, sufficient pilling prevention performance has not necessarily been obtained.

JP-A-2002-51555 (Patent Literature 2) describes a technique of treating animal hair with a protease and a transglutaminase. In addition, WO 2009/066785 A (Patent Literature 3) describes a technique of attaching a wheat protein partial hydrolysate to fibers followed by making a transglutaminase act. With the methods of Patent Literature 2 and 3, sufficient pilling prevention performance has not been obtained.

CITATIONS LIST

Patent Literatures

• Patent Literature 1: JP-A-3-213574
• Patent Literature 2: JP-A-2002-51555
• Patent Literature 3: WO 2009/066785 A

SUMMARY OF INVENTION

Technical Problems

The present invention has been devised in view of the above circumstances of the prior art, and an object thereof is to provide a modification method in which animal hair having an anti-pilling property can be obtained through simple treatment.

Solutions to Problems

The present invention provides the following embodiments.

• • [1] A method for modifying animal hair, including:
    • a reduction treatment step of treating animal hair with a reduction treatment liquid containing a reducing agent under a neutral or weakly alkaline condition; and
    • an enzyme treatment step of treating the animal hair subjected to the reduction treatment with an enzyme treatment liquid containing a protein and a transglutaminase.
  • [2] The modification method according to [1], wherein the neutral or weakly alkaline is pH 7 to pH 9.
  • [3] The modification method according to [1] or [2], wherein the reducing agent is a physiologically acceptable reducing agent.
  • [4] The modification method according to [3], wherein the physiologically acceptable reducing agent is a sulfite salt, a bisulfite salt, an oxalate salt, a formate salt, a gallate salt, or a mixture thereof.
  • [5] The modification method according to any one of [1] to [4], wherein the protein is a water-soluble protein.
  • [6] The modification method according to any one of [1] to [5], wherein the animal hair is goat hair or wool.
  • [7] The modification method according to any one of [1] to [6], wherein the reduction treatment step is performed at a temperature of 70 to 95° C. for 10 to 120 minutes.
  • [8] The modification method according to any one of [1] to [7], wherein the enzyme treatment step is performed at a temperature of 30 to 60° C. for 30 to 180 minutes.
  • [9] Animal hair obtained by the treatment method according to any one of claims 1 to 8.
  • [10] A processed product obtained from the animal hair according to [9].

Advantageous Effects of Invention

The present invention is a technique relating to modification treatment of animal hair, and is a treatment technique for providing animal hair having high anti-pilling properties suitable in terms of safety and treatment cost. The anti-pilling effect acquired by the present invention makes it possible to provide processed wool fiber having superior washing resistance, and enables the processed wool fiber to be used widely for applications or products difficult with processed fibers of conventional wool or other animal hairs.

DESCRIPTION OF EMBODIMENTS

The method for modifying animal hair of the present invention includes a reduction treatment step of treating animal hair with a reduction treatment liquid containing a reducing agent under a neutral or weakly alkaline condition, and an enzyme treatment step of treating the animal hair subjected to the reduction treatment with an enzyme treatment liquid containing a water-soluble protein and a transglutaminase. The modification method of the present invention is mainly intended to the modification of animal hair, but the treatment of the present invention may be performed on a blended fiber including artificial fiber such as polyester fiber and animal hair. However, the effect of the treatment of the present invention cannot be expected for artificial fibers.

[Animal Hair]

As the animal hair to be modified by the modification method of the present invention, animal fiber containing natural keratin is preferably used as a raw material. Examples of the animal hair include wool, goat hair, rabbit hair, and alpaca hair. Examples of the fiber form thereof include hair, yarn, knitted product, and woven product.

[Reduction Treatment Step]

In the present invention, animal hair is treated with a reduction treatment liquid containing a reducing agent under a neutral or weakly alkaline condition. The neutral or weakly alkaline, expressed in pH, is pH 7 to 9, but this is not necessarily the case. Therefore, the treatment may be performed in a slightly acidic region (specifically, a region of pH 6 to 7) to an alkaline region exceeding pH 9, but the treatment is mainly performed in a region of pH 7 to 9. The pH is preferably adjusted with a buffer.

The reducing agent is not particularly limited as long as it is a compound that acts on a substance to reduce the substance and is physiologically acceptable, but it is preferable to use an edible agent such as a sulfite salt, a bisulfite salt, an oxalate salt, a formate salt, or a gallate salt in consideration of environmental problems. It is to be noted that physiologically acceptable means physiologically low-toxic or nontoxic.

The reduction treatment liquid is an aqueous solution containing the reducing agent, and the blending amount of the reducing agent is 5% owf (owf is an abbreviation of “on the weight of fiber” and represents the weight with respect to the fiber weight) to 25% owf, preferably 10% owf to 20% owf, and more preferably 12 to 18% owf with respect to the fiber. If the blending amount is less than 5% owf, the reduction treatment is advanced insufficiently to result in an insufficient final anti-pilling property. If the blending amount is more than 25% owf, there is no problem, but the anti-pilling does not increase with the increase in the blending amount and the reducing agent is wasted.

The reaction time in the reduction treatment step is not particularly limited as long as the reducing agent can act on the fiber, but is 10 to 120 minutes, preferably 15 to 90 minutes, and more preferably 30 to 60 minutes. If the reaction time is less than 10 minutes, the reduction proceeds insufficiently, and even if the reaction time exceeds 120 minutes, the reduction amount does not increase. The reaction temperature is also not particularly limited as long as the reducing agent can act on the fiber, but is preferably 70° C. or higher. The upper limit thereof is 95° C. or lower. When the reaction temperature is lower than 70° C., the reducing ability is insufficient, whereas when the reaction temperature is higher than 95° C., the fiber may be damaged. After the fiber is immersed in the treatment liquid, any method of shaking, jetting, and stirring may be used, but a method of increasing contact between the fiber and the treatment liquid is preferable.

[Enzyme Treatment Step]

The animal hair obtained in the reduction treatment step is then subjected to an enzyme treatment step. In the enzyme treatment step, the animal hair subjected to the reduction treatment is treated with an enzyme treatment liquid (aqueous solution) containing a water-soluble protein and a transglutaminase.

The water-soluble protein according to the present invention is not particularly limited as long as it is a water-soluble protein derived from an animal or a plant, but it is preferable to use an animal-derived water-soluble protein. The water-soluble protein is a water-soluble protein among proteins obtained from animals and plants, and is obtained directly from an animal or a plant or through a specific treatment, and examples thereof include gelatin, soybean protein, milk protein, and peptide. In the present invention, animal-derived gelatin is preferred. The water-soluble protein is preferably blended in an amount of 3% owf to 25% owf, more preferably 5% to 15% owf, and still more preferably 5% owf to 10% owf mass % with respect to the fiber. When the blending amount is less than 3% owf, there is a disadvantage that the anti-pilling property is deteriorated or the texture is deteriorated due to an insufficient binding amount of the protein by a transglutaminase. When the blending amount exceeds 25% owf, there is no problem, but improvement of the anti-pilling effect by excessive addition cannot be expected, and the added protein is wasted.

In the enzyme treatment liquid of the present invention, a transglutaminase is used as an enzyme. A transglutaminase is an enzyme that acts on amino acid residues of glutamic acid and lysine on a protein to crosslink the protein, and may be any one as long as it has activity. As to the source thereof, those derived from various sources such as those derived from mammals, those derived from fish, and those derived from microorganisms are known, and any of them may be used. The transglutaminase is preferably blended in an amount of 0.1 U/g-fiber (activity value of transglutaminase for 1 g of processed fiber) to 100 U/g-fiber, more preferably 1 U/g-fiber to 50 U/g-fiber, and still more preferably 5 U/g-fiber to 25 U/g-fiber. When the blending amount is less than 0.1 U/g-fiber, there is a disadvantage that the anti-pilling effect and the texture are deteriorated due to an insufficient binding amount of the protein. When the blending amount exceeds 100 U/g-fiber, there is no problem, but improvement of the anti-pilling effect by excessive addition cannot be expected, and the added transglutaminase is wasted.

Examples of the enzyme treatment step of the present invention include a method in which animal hair obtained in the reduction treatment step is immersed in an enzyme treatment liquid containing a water-soluble protein and a transglutaminase. The reaction time in the enzyme treatment step is not particularly limited as long as the transglutaminase can act on animal hair, but is preferably 30 minutes or more, and more preferably 60 minutes or more. The upper limit of the treatment time is 180 minutes or less, and preferably 90 minutes or less. When the treatment time is less than 30 minutes, the enzyme treatment proceeds insufficiently, and even when it exceeds 180 minutes, the performance does not increase according to the increase in time capacity. The reaction temperature is not particularly limited as long as the transglutaminase can retain the activity, but is preferably 30 to 60° C., and more preferably 40 to 50° C. When the reaction temperature is lower than 30° C., the enzyme treatment proceeds insufficiently, and conversely, the enzyme treatment at a temperature higher than 60° C. is not realistic.

The animal hair subjected to the treatment according to the present invention is animal hair having the features described below. A characteristic of the animal hair according to the present invention which should be emphasized is that the animal hair is superior in anti-pilling property, and the animal hair according to the present invention can be widely used for applications and products that have been difficult with the animal hair according to the prior art.

The animal hair of the present invention is a product prepared by subjecting animal hair to reduction treatment under a neutral to weakly alkaline pH condition, and further making a transglutaminase act in the presence of a water-soluble protein. Examples of the form of the processed animal hair products include coats, sweaters, pants, jackets, mufflers, lap robes, gloves, and hats, but the form is not particularly limited.

In the present description, the “piling property” means that fibers are entangled with each other and pills are formed on a surface, and is found on knitted products and woven products. The pilling property can be determined in accordance with the testing methods for pilling of woven products and knitted products of JIS L 1076, and is expressed as a pilling grade.

As the reducing agent to be used in the treatment step, a chemical approved as a food and/or a food additive is used, and the reducing agent makes it possible to provide a technique that is useful not only in terms of sustainability but also in terms of safety.

EXAMPLES

Hereinafter, the present invention will be described with reference to Examples, but the scope of the present invention is not limited thereby.

[Example 1] Modification Treatment and Anti-Pilling Test for Goat Hair

Where the pH condition in goat hair modification treatment was set neutral, the influence on the pilling effect was examined.

A reduction treatment solution having a bath ratio of 1:30 with respect to the weight of a knitted fabric of 100% goat hair was used. The reduction treatment solution was prepared by dissolving 12% owf of sodium sulfite as a reducing agent and 2 g/L of a pH 7 sodium phosphate buffer. The knitted fabric was shaken for 60 minutes using a horizontal shaker to perform reduction treatment.

After the reduction treatment, water washing and dehydration were performed, and treatment in which a transglutaminase was made to act in the presence of protein (hereinafter, transglutaminase treatment) was performed using a treatment solution having a bath ratio of 1:30 as in the reduction treatment. The transglutaminase treatment liquid was prepared by dissolving 10% owf of gelatin APH-100 (porcine skin-derived gelatin manufactured by Nitta Gelatin Inc.) and 15 U/g-fiber of a transglutaminase. The goat hair was shaken at 50° C. for 60 minutes using a horizontal shaker. After the transglutaminase treatment, a knitted fabric washed with water, dehydrated, and dried was obtained. The knitted fabric obtained was evaluated for anti-pilling property and texture.

Anti-Pilling Test

Evaluation was performed using an ICI type tester in accordance with the JIS L 1076 A method. The result is shown in Table 1.

Evaluation of Texture

In the present description, the “texture” is a subjective evaluation that expresses a hand touch feeling or a skin touch feeling of a fiber, a woven product, or a knitted product with a sense of human sensory. The evaluation of texture performed in examples was performed by relative evaluation with respect to an unprocessed fabric. Sensory evaluation was performed on softness, warmness, swelling, and slimy feeling, and the results were all good.

Example 2

Where the pH condition in wool treatment was set neutral, the influence on the pilling effect to the treated wool prepared was examined.

A knitted fabric of 100% wool was subjected to the modification treatment in the same manner as in Example 1, affording a knitted fabric, and the anti-pilling property and the texture thereof were evaluated in the same manner as in Example 1. The result of the anti-pilling property is described in Table 1.

Evaluation of Texture

Sensory evaluation was performed on softness, warmness, swelling, and slimy feeling, and the results were all good.

[Example 3] Modification Treatment and Anti-Pilling Property Evaluation for Goat Hair

For goat hair, in the case where the pH condition in Example 1 was changed to weakly alkaline, the influence on the pilling effect to the treated goat hair prepared was examined.

A knitted fabric of 100% goat hair was modified through the same treatment as in Example 1 with the condition in the reduction treatment modified to pH 8, affording a knitted fabric, and the anti-pilling property and the texture thereof were evaluated in the same manner as in example 1. The result of the anti-pilling property is described in Table 1.

Evaluation of Texture

Sensory evaluation was performed on softness, warmness, swelling, and slimy feeling, and the results were all good.

	TABLE 1
	Goat hair	Wool
Materials	Example 1	Example 3	Example 2
Reduction treatment pH	pH 7	pH 8	pH 7
Pilling grade in anti-	Grade 4.0	Grade 4.0	Grade 4.5
pilling property test

[Comparative Example 1] Evaluation of Pilling Test of Goat Hair Knitted Fabric Treated Under Weakly Acidic Conditions

A knitted fabric of 100% goat hair was subjected to modification treatment in the same manner as in Example 1 except that the condition in the reduction treatment in Example 1 was modified to pH 5, affording a knitted fabric, and the anti-pilling property thereof were evaluated in the same manner as in Example 1. As a result of performing the reduction treatment under a weakly acidic pH condition, the pilling grade of Grade 2.5 was obtained.

[Comparative Example 2] Evaluation of Pilling Test of Goat Hair Knitted Fabric Subjected to Decomposition Enzyme Treatment and Transglutaminase Treatment of Patent Literature 2

A decomposition enzyme treatment solution having a bath ratio of 1:30 with respect to the weight of a knitted fabric of 100% goat hair was used. The decomposition enzyme treatment solution was prepared by dissolving 0.59% owf of BIOPRASE APL-30 (manufactured by Nagase ChemteX Corporation) as a decomposition enzyme and 2 g/L of a pH 8 sodium phosphate buffer. Cashmere was shaken at 44° C. for 40 minutes using a horizontal shaker to perform a decomposition enzyme treatment.

After the decomposition enzyme treatment, the enzyme was deactivated by heating at 80° C. for 10 minutes, followed by washing with water and dehydration. Next, transglutaminase treatment was performed in the same manner as in Example 1 with a transglutaminase treatment liquid to which no water-soluble protein was added, followed by washing with water, dehydration, and drying. In this treatment, the pilling grade was Grade 1.5, and the anti-pilling property was not improved.

[Comparative Example 3] Evaluation of Pilling Test of Goat Hair Knitted Fabric Subjected to Transglutaminase Treatment of Patent Literature 3

For a knitted fabric of 100% goat hair, only transglutaminase treatment was performed using the gelatin of Example 1 as a wheat protein. In this treatment, the pilling grade was Grade 1.5, and the anti-pilling property was not improved.

Claims

1. A method for modifying animal hair, comprising:

a reduction treatment step of treating animal hair with a reduction treatment liquid containing a reducing agent under a neutral or weakly alkaline condition; and

an enzyme treatment step of treating the animal hair subjected to the reduction treatment with an enzyme treatment liquid containing a protein and a transglutaminase.

2. The modification method according to claim 1, wherein the neutral or weakly alkaline is pH 7 to pH 9.

3. The modification method according to claim 1, wherein the reducing agent is a physiologically acceptable reducing agent.

4. The modification method according to claim 3, wherein the physiologically acceptable reducing agent is a sulfite salt, a bisulfite salt, an oxalate salt, a formate salt, a gallate salt, or a mixture thereof.

5. The modification method according to claim 1, wherein the protein is a water-soluble protein.

6. The modification method according to claim 1, wherein the animal hair is goat hair or wool.

7. The modification method according to claim 1, wherein the reduction treatment step is performed at a temperature of 70 to 95° C. for 10 to 120 minutes.

8. The modification method according to claim 1, wherein the enzyme treatment step is performed at a temperature of 30 to 60° C. for 30 to 180 minutes.

9. Animal hair obtained by the treatment method according to claim 1.

10. A processed product obtained from the animal hair according to claim 9.