Fiber-Treating Agent

The present invention relates to a fiber-treating agent for imparting water resistance, heat resistance and heat shape memory ability to naturally derived fibers, and preferably relates to a fiber-treating agent for naturally derived fibers used in fiber products such as headdress products such as wigs and extensions.

Unlike synthetic fibers, naturally derived fibers generally have natural texture and appearance originating from a natural material. Among naturally derived fibers, regenerated protein fibers, for example, regenerated collagen fibers, are obtained by solubilizing acid-soluble collagen or by solubilizing acid-insoluble collagen with an alkali or an enzyme to obtain a spinning stock solution, and discharging the spinning stock solution into a coagulation bath through a spinning nozzle to form fibers.

However, naturally derived fibers generally have higher hydrophilicity and hence higher water absorption as compared to synthetic fibers, and the fibers have generally low mechanical strength when they contain a large amount of water, and in particular, regenerated protein fibers have extremely low mechanical strength. This leads to deterioration of suitability as a fiber product such that during washing, mechanical strength significantly deteriorates because of the higher water absorption, and during subsequent drying, rupture occurs.

Among naturally derived fibers, regenerated protein fibers also have a problem of low heat resistance, so that, for example, if a heat set using a hair iron or the like is performed at a temperature as high as that for human hair, shrinkage or crimping occurs, resulting in impairment of visual quality.

Further, in plastic synthetic fibers, the shape in a heat set with an iron or the like is continuously memorized even after subsequent washing (there is heat shape memory ability), whereas in naturally derived fibers, the shape in a heat set with an iron or the like is lost through subsequent one time washing (there is no heat shape memory ability). Therefore, naturally derived fibers may be inferior to conventional plastic synthetic fibers in terms of degree of freedom of shape set.

The above points were supposed to be factors in limiting popularization of naturally derived fibers, in particular regenerated protein fibers for fiber products such as headdress products. In particular, water resistance, that is, a decrease in mechanical strength when it is wet has a significant impact.

On the other hand, in the field of human hair fibers which are naturally derived fibers, a method is known in which to human hair fibers having essentially no heat shape memory ability, a specific aldehyde derivative and phenolic compound are applied for newly imparting heat shape memory ability (Patent Literature 1).

Patent Literature 1: JP-A-2019-143281

The present invention provides a fiber-treating agent comprising the following components (A) and (B):

In some situations of production of fiber products such as headdress products, fibers are intensively extended, and in the technique disclosed in Patent Literature 1, there are cases where the stretchability (tenacity) of treated fibers is not sufficient. For this reason, it is required to enhance the stretchability of treated fibers for preventing rupture during extension. In the technique disclosed in Patent Literature 1, there are also cases where coloring of fibers is caused.

Therefore, the present invention relates to a fiber-treating agent which improves water resistance and heat resistance problematic in naturally derived fibers, imparts heat shape memory ability, improves stretchability (tenacity) and the feel of the surfaces, and causes no coloring of naturally derived fibers.

The present inventors have conducted intensive studies and as a result, found that by treating naturally derived fibers with a composition containing a compound having a carboxy group and a hydrogen bond term in Hansen solubility parameter of a certain value or less, the carboxy group of the compound penetrated into the fibers is strongly coordinated with a metal (mainly polyvalent metal) in the naturally derived fibers, so that the inside of the fibers is hydrophobized and the leakage of the compound from the fibers is prevented. As a result, the present inventors found that not only water resistance, and heat resistance in both dry state and wet state in the naturally derived fibers are improved, so that the shape can be imparted by a heat set, but also surprisingly, the stretchability (tenacity) of the naturally derived fibers is improved as compared to that before treatment and can be enhanced to a level close to that of human hair, and further, no coloring is caused, leading to completion of the present invention.

According to the present invention, it is possible to provide a fiber-treating agent which improves water resistance and heat resistance problematic in naturally derived fibers, can impart heat shape memory ability, improves stretchability (tenacity) and the feel of the surfaces, and further, causes no coloring of naturally derived fibers.

Fibers to be treated with the fiber-treating agent of the present invention are preferably metal-containing fibers, preferably naturally derived metal-containing fibers or synthetic metal-containing fibers, and among them, naturally derived metal-containing fibers are preferable. The naturally derived fiber refers to fibers which are taken from a natural animal or plant, or artificially produced fibers using a polymer or an oligomer, such as protein derived from keratin, collagen, casein, soybeans, peanuts, corn, silk flocks, silk protein (for example, silk fibroin) or the like or a polysaccharide, as a raw material. Among them, artificially produced fibers using a polymer or an oligomer, such as protein derived from keratin, collagen, casein, soybeans, peanuts, corn, silk flocks, silk protein (for example, silk fibroin) or the like or a polysaccharide, as a raw material are preferable, regenerated protein fibers using protein derived from keratin, collagen, casein, soybean protein, peanut protein, corn protein, silk protein (for example, silk fibroin) or the like as a raw material are more preferable, regenerated protein fibers such as regenerated collagen fibers made from collagen as a raw material or regenerated silk fibers made from silk fibroin as a raw material are more preferable, and regenerated collagen fibers are further more preferable.

Regenerated collagen fibers can be produced by a known technique, are not required to have a composition of collagen 100%, and may contain a natural or synthetic polymer and additives for improvement of quality. Regenerated collagen fibers are preferably in the form of filaments. Filaments are generally taken from fibers wound around a bobbin or packed in a box. It is also possible to directly use filaments coming out from a drying step in a production process of regenerated collagen fibers.

Synthetic metal-containing fibers may be metal-treated synthetic fibers. Naturally derived metal-containing fibers include those originally containing a metal such as fibers taken from a natural animal or plant. In this case, those originally containing a metal are not required to contain additional metal, but may be treated with a metal salt, as fibers treated with an aluminum salt to achieve water resistance as described in, for example, JP-A-2003-027318, and the like.

[Component (A): compound having hydrogen bond term δH in Hansen solubility parameter of 18.3 MPaor less, at least one of carboxy group or salt thereof, and no fused ring]

The component (A) is a compound having a hydrogen bond term δH in Hansen solubility parameter of 18.3 MPaor less, and having at least one of a carboxy group or a salt thereof, and no fused ring. In the present invention, the hydrogen bond term in Hansen solubility parameter refers to δH (MPa) (the energy term by the hydrogen bond between molecules) calculated at 25° C. in the DIY program using Software Package HSPiP 4th Edition 4.1.07 based on Hansen Solubility Parameters: A User's Handbook, CRC Press, Boca Raton FL, 2007. When the component (A) is a salt, examples of the salt include alkaline metal salts such as sodium salts and potassium salts.

Examples of the compound of the component (A) include the following (A1) and (A2):

Examples of the aromatic compound of the component (A1) include a compound of the following formula (1) or formula (2), or a salt thereof:

wherein ═X represents a methylidene group or an oxo group, Rrepresents a hydrogen atom, a hydroxy group, or an optionally substituted alkyl group, aryl group, alkoxy group, aryloxy group, or aralkyloxy group, and Ris an o-phenylene group, an m-phenylene group, a p-phenylene group, a benzylidene group, or an optionally substituted alkylene group, provided that when R has no aryl group, Ris an aryl group, an aryloxy group, or an aralkyloxy group; and

wherein Ato Aeach independently represent a hydrogen atom, an acetyl group, a halogen atom, or a linear or branched alkyl group, alkenyl group, alkoxy group, or alkenyloxy group having 1 to 6 carbon atoms.

In the component (A1), examples of the aromatic compound of formula (1) include a compound of the following formula (1A), (1B), or (1C):

wherein Bto Beach independently represent a hydrogen atom, an acetyl group, a halogen atom, or a linear or branched alkyl group, alkenyl group, alkoxy group, or alkenyloxy group having 1 to 6 carbon atoms, and Rrepresents a hydroxy group or a group of the following formula (1A)-a or (1A)-b:

wherein Bto Brepresent the same meaning as the Bto B, Rrepresents a hydrogen atom or a methyl group, and n represents an integer of 0 to 2;

wherein Dto Deach independently represent a hydrogen atom, an acetyl group, a halogen atom, or a linear or branched alkyl group, alkenyl group, alkoxy group, or alkenyloxy group having 1 to 6 carbon atoms, and E to E each independently represent the same group as Dto Dor a group of formula (1B)-a:

wherein m represents an integer of 0 to 4; and

wherein Rrepresents a hydrogen atom or a group of formula (1C)-a, Gand Geach independently represent a hydrogen atom, an acetyl group, a halogen atom, an optionally substituted aryl group, an aralkyl group or arylalkenyl group having 7 to 12 carbon atoms, or a linear or branched alkyl group, alkenyl group, alkoxy group, alkenyloxy group, or aroyloxy group having 1 to 6 carbon atoms, provided that when Ris a hydrogen atom, at least one of Gand Gis an optionally substituted aryl group, or an aralkyl group, arylalkenyl group, or aroyloxy group having 7 to 12 carbon atoms:

wherein Jto Jeach independently represent a hydrogen atom, an acetyl group, a halogen atom, or a linear or branched alkyl group, alkenyl group, alkoxy group, or alkenyloxy group having 1 to 6 carbon atoms.

In the compound of formula (1A), examples of the compound in which Ris a hydroxy group include 2-carboxy benzoic acid (phthalic acid) (hydrogen bond term δH in Hansen solubility parameter: 13.4 MPa) (hereinafter, a numerical value in parenthesis described after each compound name indicates the hydrogen bond term δH calculated by the above method).

In the compound of formula (1A), examples of the compound in which Ris a group of formula (1A)-a include 2-(((4-vinylbenzyl)oxy)carbonyl)benzoic acid (7.0 MPa).

In the compound of formula (1A), examples of the compound in which Ris a group of formula (1A)-b include 2-((2-(acryloyloxy)ethoxy)carbonyl)benzoic acid (9.1 MPa) and 2-((2-(methacryloyloxy)ethoxy)carbonyl)benzoic acid (8.4 MPa).

Examples of the compound of formula (1B) include 2-benzoylbenzoic acid (7.5 MPa), 2-(2-methylbenzoyl)benzoic acid (6.9 MPa), 2-(3-methylbenzoyl)benzoic acid (6.6 MPa), 2-(4-methylbenzoyl)benzoic acid (7.2 MPa), 2-(2-chlorobenzoyl)benzoic acid (7.1 MPa), 2-(3-chlorobenzoyl)benzoic acid (6.9 MPa), 2-(4-chlorobenzoyl)benzoic acid (7.5 MPa), and 2-(4-(2-(2-(acryloyloxy)ethoxy)ethoxy)benzoyl)benzoic acid (8.7 MPa).

In the compound of formula (1C), examples of the compound in which Ris a hydrogen atom include phenylsuccinic acid (15.8 MPa), 2,3-diphenylsuccinic acid (11.9 MPa), and (+)-di-p-toluoyl-D-tartaric acid (10.2 MPa).

In the compound of formula (1C), examples of the compound in which Ris a group of formula (1C)-a include 4-oxo-4-((4-vinylbenzyl)oxy)butanoic acid (10.1 MPa).

In addition, examples of the compound which is included in formula (1) but is not included in any of formula (1A), (1B), and (1C) include 3-carboxybenzoic acid (isophthalic acid) (12.9 MPa), 4-carboxybenzoic acid (terephthalic acid) (13.7 MPa), 3-benzoylbenzoic acid (7.2 MPa), and 4-benzoylbenzoic acid (7.9 MPa). The numerical value in parenthesis described after each compound name is the hydrogen bond term δH calculated by the above method.

In the component (A1), specific examples of the aromatic compound of formula (2) include benzoic acid (9.5 MPa), 2-methylbenzoic acid (8.4 MPa), 3-methylbenzoic acid (8.0 MPa), 4-methylbenzoic acid (8.8 MPa), 2-ethylbenzoic acid (7.7 MPa), 3-ethylbenzoic acid (7.4 MPa), 4-ethylbenzoic acid (8.1 MPa), 2-propylbenzoic acid (7.0 MPa), 3-propylbenzoic acid (6.7 MPa), 4-propylbenzoic acid (7.4 MPa), 2-isopropylbenzoic acid (6.7 MPa), 3-isopropylbenzoic acid (6.5 MPa), 4-isopropylbenzoic acid (7.1 MPa), 2-n-butylbenzoic acid (6.8 MPa), 3-n-butylbenzoic acid (6.5 MPa), 4-n-butylbenzoic acid (7.2 MPa), 2-tert-butylbenzoic acid (6.1 MPa), 3-tert-butylbenzoic acid (5.9 MPa), 4-tert-butylbenzoic acid (6.5 MPa), 2-vinylbenzoic acid (8.0 MPa), 3-vinylbenzoic acid (7.7 MPa), 4-vinylbenzoic acid (8.5 MPa), 2-acetylbenzoic acid (8.6 MPa), 3-acetylbenzoic acid (8.2 MPa), 4-acetylbenzoic acid (8.9 MPa), 2-methoxybenzoic acid (9.7 MPa), 3-methoxybenzoic acid (9.3 MPa), 4-methoxybenzoic acid (10.1 MPa), 2-chlorobenzoic acid (8.7 MPa), 3-chlorobenzoic acid (8.4 MPa), 4-chlorobenzoic acid (9.2 MPa), 2-bromobenzoic acid (9.1 MPa), 3-bromobenzoic acid (8.8 MPa), and 4-bromobenzoic acid (10.1 MPa). Among them, 4-ethylbenzoic acid, 4-vinylbenzoic acid, and benzoic acid are preferable.

In the component (A1), examples of the compound other than the compounds of formulas (1) and (2) include phenylbutanoic acid.

Examples of the compound of the component (A2) include potassium 2,4-hexadienoate (12.5 MPa).

The hydrogen bond term δH of the aromatic compound of the component (A1) is preferably 16.0 MPaor less, more preferably 13.5 MPaor less, further more preferably 12.0 MPaor less, further more preferably 10.0 MPaor less, and preferably 3.0 MPaor more, more preferably 4.0 MPaor more, further more preferably 5.0 MPaor more, from the viewpoint of moderately hydrophobizing the inside of fibers.

The hydrogen bond term δH of the compound of the component (A2) is preferably 16.0 MPaor less, more preferably 15.0 MPaor less, further more preferably 14.0 MPaor less, further more preferably 13.0 MPaor less, and preferably 11.0 MPaor more, more preferably 11.5 MPaor more, further more preferably 12.0 MPaor more, from the viewpoint of moderately hydrophobizing the inside of fibers.

Hereinafter, the preferred content of the component (A) is described in accordance with the kind of the component (A). Here, in the present invention, in the case where the component (A) is a salt, the content of the component (A) refers to the content of the corresponding acid form. The content of the component (A) varies different depending on the pH range of the fiber-treating agent, and the following range is preferable.