WO2023224000A1

WO2023224000A1 - Modified regenerated collagen fiber, production method therefor, and headdress product containing same

Info

Publication number: WO2023224000A1
Application number: PCT/JP2023/018107
Authority: WO
Inventors: 淳一古川; 光平川村; 和宇大平
Original assignee: 花王株式会社; 株式会社カネカ
Priority date: 2022-05-18
Filing date: 2023-05-15
Publication date: 2023-11-23
Also published as: JP2023171309A

Abstract

The present invention relates to modified regenerated collagen fibers: in which water resistance and heat resistance, which are problems in regenerated collagen fibers, are improved; to which thermal shape memory is imparted; that are also superior in terms of the elasticity (tenacity) and the surface feel; and that are, moreover, not colored.　Modified regenerated collagen fibers according to the present invention are formed by containing 1.0 mass% or more of a component (A), indicated below, in the form of benzoic acid in regenerated collagen fibers.　(A) Benzoic acid or a salt thereof

Description

Modified regenerated collagen fiber, method for producing the same, and headdress products containing the same

The present invention relates to regenerated collagen fibers imparted with water resistance, heat resistance, and thermal shape memory ability, and preferably relates to regenerated collagen fibers used in textile products such as headdress products such as wigs and extensions.

Regenerated collagen fibers generally have a natural texture and appearance that come from natural materials, unlike synthetic fibers. The regenerated collagen fibers are obtained by solubilizing acid-soluble collagen or insoluble collagen with an alkali or enzyme to obtain a spinning solution, which is then discharged into a coagulation bath through a spinning nozzle to form fibers.

However, regenerated collagen fibers generally have higher water absorption than synthetic fibers because they are more hydrophilic, and their mechanical strength is extremely low when they contain a large amount of water. For this reason, during washing, the mechanical strength is significantly reduced due to the high water absorption rate, and the fibers break during subsequent drying, leading to a decline in their suitability as textile products such as headdresses.

In addition, regenerated collagen fibers also have the problem of low heat resistance; for example, when heat-set using a hair iron, etc., if set at a high temperature similar to that of human hair, shrinkage and frizz will occur. This will spoil the appearance.

Furthermore, plastic synthetic fibers retain their shape even after subsequent washing (they have thermal shape memory), but regenerated collagen fibers retain their shape when heat-set with an iron, etc. Because it is lost after a single wash (it does not have thermal shape memory), it is inferior to conventional plastic synthetic fibers in terms of the degree of freedom in shape setting.

The above points have been factors that have hindered the spread of regenerated collagen fibers in textile products. In particular, the influence of water resistance, that is, a decrease in mechanical strength when wet, was significant.
On the other hand, in the field of human hair fibers, a method is known in which specific aldehyde derivatives and phenolic compounds are applied to human hair fibers, which do not originally have thermal shape memory ability, in order to impart new thermal shape memory ability. (Patent Document 1).

(Patent Document 1) Japanese Patent Application Publication No. 2019-143281

The present invention provides modified regenerated collagen fibers containing 1.0% by mass or more of the following component (A) as benzoic acid in the regenerated collagen fibers.
(A) Benzoic acid or its salts

Furthermore, the present invention provides a method for treating regenerated collagen fibers, which includes the following step (i).
Step (i) Step of immersing regenerated collagen fibers in a fiber treatment agent containing the following component (A) (A) Benzoic acid or its salt

Furthermore, the present invention provides a method for producing modified regenerated collagen fibers, which includes a step of treating regenerated collagen fibers by the above-mentioned method for treating regenerated collagen fibers.

Furthermore, the present invention provides a method for manufacturing a headdress product, which includes a step of treating regenerated collagen fibers by the above-described regenerated collagen fiber treatment method.

Furthermore, the present invention provides a headdress product containing the above-mentioned modified regenerated collagen fiber as a constituent element.

Detailed description of the invention

In the production of textile products, there are cases where fibers are strongly stretched, and the technique described in Patent Document 1 sometimes does not provide sufficient stretchability (tenacity) of the fibers after treatment. Therefore, in order to prevent breakage during elongation, there has been a demand for increasing the elasticity of the treated fibers.
Furthermore, in the technique described in Patent Document 1, the fibers were sometimes colored.

Therefore, the present invention improves water resistance and heat resistance, which are problems in regenerated collagen fibers, provides thermal shape memory ability, has excellent elasticity (tenacity) and surface feel, and has no coloration. This invention relates to modified and regenerated collagen fibers.

As a result of intensive research, the present inventors have found that modified regenerated collagen fibers containing benzoic acid or its salt have a structure in which the carboxy groups of the benzoic acid or its salt are metals (mainly polyvalent metals) in the regenerated collagen fibers. It has been found that benzoic acid or its salts are strongly coordinated with the fibers, thereby making the interior of the fibers hydrophobic and preventing leakage of benzoic acid or its salts from the fibers. As a result, these modified regenerated collagen fibers not only have improved water resistance and heat resistance in both dry and wet conditions, and can be given shape by heat setting, but also surprisingly have elasticity (tenacity). The present invention was completed based on the discovery that the hair's hair quality was improved compared to before the treatment, reaching a level close to that of human hair, and that there was no coloration associated with the modification treatment.

According to the present invention, water resistance and heat resistance, which are problems of regenerated collagen fibers, are improved, thermal shape memory ability is imparted, elasticity (tenacity) and surface feel are improved, and coloring is improved. No modification can provide regenerated collagen fibers.

[Fibers to be treated in the present invention]
The fibers to be subjected to the fiber treatment of the present invention are fibers artificially manufactured using collagen-derived polymers or oligomers as raw materials, that is, regenerated collagen fibers using collagen as raw materials.

Regenerated collagen fibers can be produced using known techniques, and the composition does not need to be 100% collagen, and may contain natural or synthetic polymers and additives for quality improvement. Furthermore, the regenerated collagen fibers may be post-processed. The preferred form of the regenerated collagen fibers is filaments. Filament is generally taken out from a bobbin wound or boxed state. Furthermore, the filaments that come out of the drying process can also be used directly in the process of producing regenerated collagen fibers.

It is preferable to use floor skin as the raw material for collagen used in the production of regenerated collagen fibers. The bedding skin can be obtained, for example, from fresh bedding skin obtained by slaughtering a domestic animal such as a cow, or from salted rawhide. Most of these bedding skins are made up of insoluble collagen fibers, but they are usually used after removing the fleshy parts attached to them in a network and removing the salt used to prevent rot and deterioration.

These insoluble collagen fibers contain impurities such as lipids such as glycerides, phospholipids, and free fatty acids, glycoproteins, and proteins other than collagen such as albumin. These impurities greatly affect spinning stability, quality such as gloss and strength and elongation, and odor during fiberization. Therefore, for example, after soaking in lime to hydrolyze the fat content in insoluble collagen fibers and loosen the collagen fibers, conventional leather treatments such as acid/alkali treatment, enzyme treatment, and solvent treatment are applied to the leather. It is preferable to remove these impurities.

The insoluble collagen that has been treated as described above is subjected to a solubilization treatment in order to cleave the crosslinked peptide portions. As a method for such solubilization treatment, commonly employed known alkali solubilization methods, enzyme solubilization methods, etc. can be applied. Furthermore, the alkali solubilization method and the enzyme solubilization method may be used in combination.

When applying the alkali solubilization method, it is preferable to neutralize with an acid such as hydrochloric acid. Note that as an improved method of the conventionally known alkali solubilization method, the method described in Japanese Patent Publication No. 15033/1983 may be used.

The enzyme solubilization method has the advantage of being able to obtain solubilized collagen with a uniform molecular weight, and is a method that can be suitably employed in the present invention. As such an enzyme solubilization method, for example, methods described in Japanese Patent Publication No. 43-25829, Japanese Patent Publication No. 43-27513, etc. can be adopted.

When collagen that has been solubilized in this way is further subjected to operations such as pH adjustment, salting out, water washing, and solvent treatment, it is possible to obtain regenerated collagen fibers with excellent quality. It is preferable to perform these treatments.

The obtained solubilized collagen is dissolved in an acid such as hydrochloric acid, acetic acid, or lactic acid, has a pH of 2 to 4.5, and has a collagen concentration of 1% by mass or more, preferably 2% by mass or more, or 15% by mass. Hereinafter, the collagen aqueous solution is adjusted to preferably have a content of 10% by mass or less. The collagen aqueous solution may be defoamed under vacuum stirring or filtered to remove fine dust that is water-insoluble, if necessary. In addition, the collagen aqueous solution may contain stabilizers, if necessary, for the purpose of improving mechanical strength, improving water resistance and heat resistance, improving gloss, improving spinnability, preventing discoloration, preservatives, etc. , a water-soluble polymer compound, and other additives may be added in appropriate amounts.

Regenerated collagen fibers are formed by discharging the collagen aqueous solution through, for example, a spinning nozzle or slit and immersing it in an inorganic salt aqueous solution. As the inorganic salt aqueous solution, for example, an aqueous solution of a water-soluble inorganic salt such as sodium sulfate, sodium chloride, ammonium sulfate, etc. is used. Usually, the concentration of these inorganic salts in the inorganic salt aqueous solution is adjusted to 10 to 40% by mass. The pH of the inorganic salt aqueous solution is preferably 2 or more, more preferably 4 or more, and preferably 13 or less, more preferably 12 or less. To adjust this pH, for example, metal salts such as sodium borate and sodium acetate, hydrochloric acid, boric acid, acetic acid, sodium hydroxide, etc. can be used. When the pH of the inorganic salt aqueous solution is within the above range, the peptide bonds of collagen are less susceptible to hydrolysis, making it easier to obtain the desired fibers. Further, the temperature of the inorganic salt aqueous solution is not particularly limited, but it is usually 35°C or lower because it does not cause denaturation of soluble collagen, does not reduce the strength of spun fibers, and facilitates the production of stable threads. This is desirable. Note that the lower limit of the temperature of the inorganic salt aqueous solution is not particularly limited, but can be adjusted as appropriate depending on the solubility of the inorganic salt.

The regenerated collagen fibers may be pretreated (crosslinked) by immersing them in an epoxy compound or a solution thereof. The amount of the epoxy compound is preferably 0.1 equivalent or more, more preferably 0.5 equivalent or more, and still more preferably 1 equivalent or more with respect to the amount of amino groups that can react with the epoxy compound in the regenerated collagen fibers measured by amino acid analysis method. The amount is preferably 500 equivalents or less, more preferably 100 equivalents or less, and even more preferably 50 equivalents or less. When the amount of the epoxy compound is within the above range, it is possible to sufficiently impart an effect of insolubilizing the regenerated collagen fibers to water, and it is also preferable in terms of industrial handling and environmental aspects.

Epoxy compounds are used as they are or dissolved in various solvents. Examples of solvents include water; alcohols such as methyl alcohol, ethyl alcohol, and isopropanol; ethers such as tetrahydrofuran and dioxane; halogenated organic solvents such as dichloromethane, chloroform, and carbon tetrachloride; dimethylformamide (DMF), and dimethyl sulfoxide. Examples include neutral organic solvents such as (DMSO). These solvents may be used alone or in combination of two or more. When using water as a solvent, an aqueous solution of an inorganic salt such as sodium sulfate, sodium chloride, ammonium sulfate, etc. may be used as necessary. Usually, the concentration of the inorganic salt in the aqueous solution of the inorganic salt is adjusted to 10 to 40% by mass. Further, the pH of the aqueous solution may be adjusted using, for example, metal salts such as sodium borate and sodium acetate, hydrochloric acid, boric acid, acetic acid, sodium hydroxide, and the like. In this case, the pH of the aqueous solution is preferably 6 or higher, more preferably 8 or higher, from the viewpoint of not slowing down the reaction between the epoxy group of the epoxy compound and the amino group of collagen and ensuring sufficient insolubilization in water. Furthermore, since the pH of an aqueous solution of an inorganic salt tends to decrease over time, a buffer may be used if necessary.

The temperature at which the regenerated collagen fibers are treated with the epoxy compound is preferably 50°C or lower, from the viewpoints that the regenerated collagen fibers do not denature, the strength of the obtained fibers does not decrease, and stable yarn production is facilitated. .

The regenerated collagen fibers may then be washed with water, oiled, and dried. Washing with water can be carried out, for example, by washing with running water for 10 minutes to 4 hours. As the oil agent used for oiling, for example, an oil agent made of an emulsion such as an amino-modified silicone, an epoxy-modified silicone, a polyether-modified silicone, or a Pluronic type polyether antistatic agent can be used. The drying temperature is preferably 100°C or lower, more preferably 75°C or lower.

The regenerated collagen fibers to be treated preferably contain a polyvalent metal, a salt thereof, or a complex thereof from the viewpoint of improving water resistance. Examples of polyvalent metals include calcium, magnesium, strontium, barium, zinc, chromium, aluminum, titanium, zirconium, tin, lead, antimony, iron, and copper, which improve water resistance, reduce coloration of fibers, From the viewpoint of reducing environmental impact and improving economic efficiency, aluminum, zirconium, and titanium are preferably used, and aluminum is more preferably used. From the viewpoint of improving water resistance, the content of the polyvalent metal, its salt, or its complex in the regenerated collagen fibers is preferably 1.0% by mass or more, more preferably 2.0% by mass or more, still more preferably The content is 3.0% by mass or more, even more preferably 5.0% by mass or more, and from the viewpoint of improving the feel of the fiber surface, preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less. , even more preferably 10% by mass or less.
That is, from the above point of view, the content of the polyvalent metal, its salt, or its complex in the regenerated collagen fibers to be treated is preferably 1.0 to 40% by mass, more preferably 2.0 to 30% by mass, as the amount of metal element. , more preferably 3.0 to 20% by weight, even more preferably 5.0 to 10% by weight.

[Fiber processing method]
(Basic processing)
The fiber processing method of the present invention includes the following step (i), which improves water resistance and heat resistance, which are problems of regenerated collagen fibers, imparts thermal shape memory ability, and provides elasticity. It is possible to produce modified regenerated collagen fibers that have improved properties (tenacity) and surface feel, and are free from coloration.
Step (i) Step of immersing regenerated collagen fibers in a fiber treatment agent containing the following component (A) (A) Benzoic acid or its salt

The content of component (A) in the fiber treatment agent used in step (i) varies depending on the pH range of the fiber treatment agent, but is preferably in the range shown below.

When the pH of the fiber treatment agent is 2.0 or more and less than 6.5, the modified regenerated collagen fibers after treatment will have high shape sustainability, water resistance, elasticity (toughness, i.e., high elongation at break when the fiber is pulled), and heat resistance. The content of component (A) in the fiber treatment agent, as benzoic acid, is preferably 0.8% by mass or more, more preferably 3.0% by mass or more, still more preferably 5.0% by mass or more, and even more preferably is 10% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, and from the viewpoint of improving the feel of the fiber surface, preferably 90% by mass or less, more preferably 80% by mass. % or less, more preferably 70% by mass or less, even more preferably 50% by mass or less, even more preferably 40% by mass or less, even more preferably 35% by mass or less.
That is, when the pH of the fiber treatment agent is 2.0 or more and less than 6.5, the content of component (A) in the fiber treatment agent is preferably 0.8 to 90% by mass, more preferably 3.0% as benzoic acid, from the above viewpoint. ~80% by weight, more preferably 5.0-70% by weight, even more preferably 10-50% by weight, even more preferably 15-40% by weight, even more preferably 20-35% by weight.

In addition, when the pH of the fiber treatment agent is 6.5 or more and 11.0 or less, the modified and regenerated collagen fibers after treatment have high shape sustainability, water resistance, elasticity (tenacity, that is, high breaking elongation when fibers are pulled) and From the viewpoint of imparting heat resistance, the content of component (A) in the fiber treatment agent is preferably 0.8% by mass or more, more preferably 3.0% by mass or more, even more preferably 5.0% by mass or more, as benzoic acid. More preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 26% by mass or more, even more preferably 28% by mass. % or more, even more preferably 30% by mass or more, and from the viewpoint of improving the feel of the fiber surface, preferably 90% by mass or less, more preferably 80% by mass or less, still more preferably 70% by mass or less, and It is more preferably 50% by mass or less, even more preferably 45% by mass or less, even more preferably 40% by mass or less.
That is, when the pH of the fiber treatment agent is 6.5 or more and 11.0 or less, the content of component (A) in the fiber treatment agent is preferably 0.8 to 90% by mass, more preferably 3.0% as benzoic acid, from the above viewpoint. ~80% by weight, more preferably 5.0~70% by weight, even more preferably 10~70% by weight, even more preferably 15~50% by weight, even more preferably 20~50% by weight, even more preferably 25~ 45% by weight, even more preferably 26-45% by weight, even more preferably 28-40% by weight, even more preferably 30-40% by weight.

The fiber treatment agent used in step (i) uses water as a medium. The content of water in the fiber treatment agent is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 40% by mass or more, and preferably 95% by mass or more. % or less, more preferably 90% by mass or less, still more preferably 85% by mass or less.
That is, the content of water in the fiber treatment agent is preferably 10 to 95% by mass, more preferably 20 to 90% by mass, even more preferably 30 to 85% by mass, and even more preferably 40 to 85% by mass. .

The pH of the fiber treatment agent used in step (i) is preferably 2.0 or higher, more preferably 3.0 or higher, still more preferably 3.5 or higher, and even more preferably 4.0 from the viewpoint of suppressing damage to regenerated collagen fibers and improving durability. or more, and preferably 11.0 or less, more preferably 10.0 or less, and even more preferably 9.0 or less. Note that the pH in the present invention is a value at 25°C.
That is, from the viewpoint of suppressing damage to regenerated collagen fibers and improving durability, the pH of the fiber treatment agent is preferably 2.0 to 11.0, more preferably 3.0 to 10.0, still more preferably 3.5 to 9.0, and even more preferably 4.0 to 9.0. It is.

In step (i), the regenerated collagen fibers subjected to fiber treatment may be dry or wet. For example, the treatment may be performed directly before drying during production of regenerated collagen fibers. The amount of fiber treatment agent in which the regenerated collagen fibers are immersed is a bath ratio (mass of fiber treatment agent/mass of regenerated collagen fibers) to the mass of the regenerated collagen fibers, preferably 2.0 or more, more preferably 3.0 or more, and even more preferably It is 5.0 or more, even more preferably 10 or more, even more preferably 20 or more, and preferably 500 or less, more preferably 250 or less, and still more preferably 100 or less.
That is, the bath ratio is preferably 2.0 to 500, more preferably 3.0 to 250, even more preferably 5.0 to 100, even more preferably 10 to 100, and even more preferably 20 to 100.

Furthermore, in step (i), the regenerated collagen fibers may be fixed in advance with a curler or the like, and then subjected to the fiber treatment of the present invention under heating. By doing so, it is possible to simultaneously impart a desired shape to the regenerated collagen fibers in addition to thermal shape memory ability and high durability.

The immersion of the regenerated collagen fibers in the fiber treatment agent in step (i) is preferably performed under heating, and this heating is performed by heating the fiber treatment agent. Note that this heating may be performed by immersing the regenerated collagen fibers in a heated fiber treatment agent, or may be performed by immersing the regenerated collagen fibers in a low-temperature fiber treatment agent and then heating. The temperature of the fiber treatment agent is preferably 20°C or higher, more preferably 20°C or higher, in order to obtain the effects of the present invention by increasing the interaction between component (A) and fiber constituent molecules in the regenerated collagen fibers, such as protein molecules. The temperature is 35°C or higher, more preferably 45°C or higher, and preferably lower than 100°C, more preferably 80°C or lower, even more preferably 70°C or lower, in order to prevent the regenerated collagen fibers from being denatured and deteriorated by heat. , more preferably 60°C or lower.

The immersion time in step (i) is appropriately adjusted depending on the heating temperature, but for example, from the viewpoint of exerting the effect of improving elasticity on regenerated collagen fibers, it is preferably 15 minutes or more, more preferably 30 minutes or more, and even more preferably The duration is 1 hour or more, and in order to suppress damage to regenerated collagen fibers, the duration is preferably 48 hours or less, more preferably 24 hours or less, and even more preferably 12 hours or less.

It is preferable that step (i) is performed in an environment where evaporation of water is suppressed. A specific method for suppressing water evaporation includes a method of covering the container of the fiber treatment agent in which the regenerated collagen fibers are immersed with a film-like substance, cap, lid, etc. made of a material that does not permeate water vapor.

After step (i), the regenerated collagen fibers may or may not be rinsed, but rinsing is preferred from the viewpoint of preventing deterioration in the feel of the regenerated collagen fiber surface due to excess component (A).

It is believed that by the treatment in step (i), component (A) penetrates into the regenerated collagen fibers and strongly coordinates with metals, such as polyvalent metals, within the fibers, thereby producing various effects. That is, by the regenerated collagen fiber processing method including step (i), it is possible to produce modified regenerated collagen fibers containing the component (A) within the fibers, and the obtained modified regenerated collagen fibers can be heat-set. The regenerated collagen fibers can be given a shape, have excellent water resistance, heat resistance, and tensile modulus, and have highly improved elasticity (tenacity) of the regenerated collagen fibers.

[Modified regenerated collagen fiber]
The modified regenerated collagen fibers of the present invention obtained by the above method will be explained below.

(Component (A): Benzoic acid or its salt)
The modified regenerated collagen fiber of the present invention contains component (A) benzoic acid or a salt thereof. Examples of when component (A) is a salt include alkali metal salts such as sodium salts and potassium salts.

The content of component (A) in the modified regenerated collagen fibers of the present invention is 1.0% by mass or more as benzoic acid from the viewpoint of having higher shape sustainability, water resistance, and heat resistance, and Preferably 5.0% by mass or more, more preferably 10% by mass or more, still more preferably 12% by mass or more, even more preferably 15% by mass or more, and from the viewpoint of improving the feel of the fiber surface, preferably 50% by mass. % or less, more preferably 40% by mass or less, still more preferably 30% by mass or less.
That is, from the above viewpoint, the content of component (A) in the modified regenerated collagen fibers of the present invention is preferably 1.0 to 50% by mass, more preferably 5.0 to 40% by mass, and still more preferably 10% by mass as benzoic acid. ~40% by weight, even more preferably 12-40% by weight, even more preferably 15-30% by weight.

(Component (B): polyvalent metal, its salt, or its complex)
The modified regenerated collagen fiber of the present invention preferably further contains (B) a polyvalent metal, a salt thereof, or a complex thereof from the viewpoint of improving water resistance. Examples of polyvalent metals include calcium, magnesium, strontium, barium, zinc, chromium, aluminum, titanium, zirconium, tin, lead, antimony, iron, and copper, which improve water resistance, reduce coloration of fibers, From the viewpoint of reducing environmental impact and improving economic efficiency, aluminum, zirconium, and titanium are preferably used, and aluminum is more preferably used. Any of these can be used alone or in combination of two or more.

From the viewpoint of improving water resistance, the content of component (B) in the modified regenerated collagen fibers of the present invention is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably 1.0% by mass. % by mass or more, even more preferably 2.0% by mass or more, even more preferably 5.0% by mass or more, and from the viewpoint of improving the feel of the fiber surface, preferably 40% by mass or less, more preferably 30% by mass or less, It is more preferably 20% by mass or less, even more preferably 10% by mass or less, even more preferably 7.0% by mass or less.
That is, from the above viewpoint, the content of component (B) in the modified regenerated collagen fibers of the present invention is preferably 0.1 to 40% by mass, more preferably 0.5 to 30% by mass, even more preferably 1.0 to 20% by weight, even more preferably 2.0 to 10% by weight, even more preferably 5.0 to 7.0% by weight.

In the modified regenerated collagen fibers of the present invention, the content of component (A) as _{benzoic acid} (component (A) benzoic _acid The _mass ratio (component (A) _{benzoic acid amount} )/(component (B) _{metal element amount} ) is preferably 0.025 or more, from the viewpoint of having higher shape sustainability, water resistance, and heat resistance. More preferably 0.2 or more, still more preferably 0.5 or more, even more preferably 1.0 or more, even more preferably 2.0 or more, even more preferably 2.5 or more, and from the viewpoint of having high durability and the fiber surface. From the viewpoint of improving the feel, it is preferably 100 or less, more preferably 50 or less, even more preferably 20 or less, even more preferably 10 or less, even more preferably 8 or less, even more preferably 6 or less, and even more preferably 4. It is as follows.
That is, from the above point of view, the mass ratio (component (A) _{amount of benzoic acid} )/(component (B) _{amount of metal element} ) in the modified regenerated collagen fibers of the present invention is preferably 0.025 to 100, more preferably 0.2. -50, more preferably 0.5-20, even more preferably 1.0-10, even more preferably 2.0-8, even more preferably 2.5-6, even more preferably 2.5-4.

The modified regenerated collagen fibers of the present invention can be given a shape by heat setting, have excellent water resistance, heat resistance, and tensile modulus, and are fibers with highly improved elasticity (tenacity) of the regenerated collagen fibers. be. Therefore, the modified regenerated collagen fibers of the present invention can be suitably used as fibers for headdress products, and various headdress products can be manufactured using the fibers.
In addition, suitable headdress products in the present invention include, for example, hair wigs, wigs, weaving, hair extensions, braided hair, hair accessories, doll hair, and the like.

The modified regenerated collagen fibers of the present invention may be used alone as a headdress product, or may be mixed with other fibers to make a headdress product. Other fibers are not particularly limited as long as they can be used for headdress products. Other fibers include, for example, polyester fibers, human hair, animal hair, polyvinyl chloride fibers, modacrylic fibers, polyamide fibers, polyolefin fibers, etc. From the viewpoint of excellent retention, polyester fibers are preferred, and flame-retardant polyester fibers are more preferred.

The flame-retardant polyester fiber is not particularly limited, but from the viewpoint of flame retardancy, the flame-retardant polyester fiber is one or more polyester resins selected from the group consisting of polyalkylene terephthalate and copolyester mainly composed of polyalkylene terephthalate. It is preferable that the brominated epoxy flame retardant is contained in an amount of 5 to 40 parts by mass. In the present invention, "containing mainly" means containing 50 mol% or more, and "copolyester mainly containing polyalkylene terephthalate" means copolymer containing polyalkylene terephthalate at 50 mol% or more. Refers to polyester. Preferably, the "copolyester mainly composed of polyalkylene terephthalate" contains polyalkylene terephthalate in an amount of 60 mol% or more, more preferably 70 mol% or more, still more preferably 80 mol% or more. Preferably, the flame-retardant polyester fiber further contains 0 to 5 parts by mass of an antimony compound based on 100 parts by mass of the polyester resin. Including an antimony compound improves the flame retardancy of the polyester fiber.

Regarding the embodiments described above, preferred aspects of the present invention will be further disclosed below.

<1>
A modified regenerated collagen fiber containing 1.0% by mass or more of the following component (A) as benzoic acid in the regenerated collagen fiber.
(A) Benzoic acid or its salts

<2>
The content of component (A) as benzoic acid is preferably 5.0% by mass or more, more preferably 10% by mass or more, still more preferably 12% by mass or more, even more preferably 15% by mass or more, and preferably is 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, the modified regenerated collagen fiber according to <1>.

<3>
Preferably, the modified regenerated collagen fiber according to <1> or <2> further contains the following component (B).
(B) Polyvalent metal, its salt or its complex

<4>
Component (B) is preferably one or more polyvalent metals selected from calcium, magnesium, strontium, barium, zinc, chromium, aluminum, titanium, zirconium, tin, lead, antimony, iron and copper, or a salt thereof or a salt thereof. The modified regenerated collagen according to <3>, which is a complex, more preferably one or more polyvalent metals selected from aluminum, zirconium, and titanium, or a salt thereof, or a complex thereof, and even more preferably aluminum, a salt thereof, or a complex thereof. fiber.

<5>
The content of component (B) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, even more preferably 2.0% by mass or more, and even more preferably 5.0% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 10% by mass or less, even more preferably 7.0% by mass or less. The modified regenerated collagen fiber according to <3> or <4>.

<6>
The mass ratio of the content of component (A) as benzoic acid to the content of component (B) as a metal element (component (A) _{benzoic acid amount} )/(component (B) _{metal element amount} ) is preferably 0.025 or more, more preferably 0.2 or more, still more preferably 0.5 or more, even more preferably 1.0 or more, even more preferably 2.0 or more, even more preferably 2.5 or more, and preferably 100 or less, more preferably 50 or less , more preferably 20 or less, even more preferably 10 or less, even more preferably 8 or less, even more preferably 6 or less, even more preferably 4 or less, according to any one of <1> to <5>. Modified regenerated collagen fibers as described.

<7>
A regenerated collagen fiber processing method comprising the following step (i).
Step (i) Step of immersing regenerated collagen fibers in a fiber treatment agent containing the following component (A) (A) Benzoic acid or its salt

<8>
Before step (i), a solubilized collagen aqueous solution obtained by solubilizing insoluble collagen fibers made from livestock animal bedding is discharged through a spinning nozzle or slit, and the regenerated collagen is immersed in an inorganic salt aqueous solution. The regenerated collagen fiber processing method according to <7>, which includes a fiber manufacturing step.

<9>
Preferably, the regenerated collagen fiber processing method according to <8>, which includes a crosslinking treatment step of immersing the regenerated collagen fibers in an epoxy compound or a solution thereof after the regenerated collagen fiber manufacturing step.

<10>
The regenerated collagen fiber processing method according to any one of <7> to <9>, wherein the regenerated collagen fiber contains the following component (B).
(B) Polyvalent metal, its salt or its complex

<11>
Component (B) is preferably one or more polyvalent metals selected from calcium, magnesium, strontium, barium, zinc, chromium, aluminum, titanium, zirconium, tin, lead, antimony, iron and copper, or a salt thereof or a salt thereof. The regenerated collagen fiber treatment according to <10>, which is a complex, more preferably one or more polyvalent metals selected from aluminum, zirconium, and titanium, or a salt thereof, or a complex thereof, and even more preferably aluminum, a salt thereof, or a complex thereof. Method.

<12>
The pH at 25°C of the fiber treatment agent used in step (i) is preferably 2.0 or higher, more preferably 3.0 or higher, even more preferably 3.5 or higher, even more preferably 4.0 or higher, and preferably 11.0 or lower, The method for treating regenerated collagen fibers according to any one of <7> to <11>, which is more preferably 10.0 or less, and even more preferably 9.0 or less.

<13>
The pH of the fiber treatment agent used in step (i) is 2.0 or more and less than 6.5, and the content of component (A) in the fiber treatment agent is preferably 0.8% by mass or more, more preferably 0.8% by mass or more as benzoic acid. 3.0% by mass or more, more preferably 5.0% by mass or more, even more preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, and preferably 90% by mass or less , more preferably 80% by mass or less, still more preferably 70% by mass or less, even more preferably 50% by mass or less, even more preferably 40% by mass or less, even more preferably 35% by mass or less, <7>~ The regenerated collagen fiber processing method according to any one of <12>.

<14>
The pH of the fiber treatment agent used in step (i) is 6.5 or more and 11.0 or less, and the content of component (A) in the fiber treatment agent is preferably 0.8% by mass or more, more preferably 3.0% as benzoic acid. mass% or more, more preferably 5.0 mass% or more, even more preferably 10 mass% or more, even more preferably 15 mass% or more, even more preferably 20 mass% or more, even more preferably 25 mass% or more, and even more Preferably 26% by mass or more, even more preferably 28% by mass or more, even more preferably 30% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, even more preferably 70% by mass. The regenerated collagen fiber treatment according to any one of <7> to <12>, which is still more preferably 50% by mass or less, even more preferably 45% by mass or less, even more preferably 40% by mass or less Method.

<15>
The fiber treatment agent used in step (i) uses water as a medium, and the content of water in the fiber treatment agent is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 30% by mass or more, Still more preferably 40% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, in any one of <7> to <14>. The regenerated collagen fiber processing method described.

<16>
The amount of the fiber treatment agent in which the regenerated collagen fibers are immersed in step (i) is a bath ratio (mass of the fiber treatment agent/mass of the regenerated collagen fiber) to the mass of the regenerated collagen fibers, preferably 2 or more, more preferably 3. <7> to <15 ＞The method for treating regenerated collagen fibers according to any one of ＞.

<17>
The temperature of the fiber treatment agent in which the regenerated collagen fibers are immersed in step (i) is preferably 20°C or higher, more preferably 35°C or higher, even more preferably 45°C or higher, and preferably lower than 100°C, more preferably The method for treating regenerated collagen fibers according to any one of <7> to <16>, wherein the temperature is 80°C or lower, more preferably 70°C or lower, even more preferably 60°C or lower.

<18>
The immersion time in step (i) is preferably 15 minutes or more, more preferably 30 minutes or more, even more preferably 1 hour or more, and preferably 48 hours or less, more preferably 24 hours or less, even more preferably 12 The regenerated collagen fiber processing method according to any one of <7> to <17>, wherein the regenerated collagen fiber processing time is 1 hour or less.

<19>
Preferably, the method for treating regenerated collagen fibers according to any one of <7> to <18>, wherein step (i) is performed in an environment where evaporation of water is suppressed.

<20>
A method for producing modified regenerated collagen fibers, comprising a step of treating regenerated collagen fibers by the regenerated collagen fiber treatment method according to any one of <7> to <19>.

<21>
A method for producing a headdress product, comprising a step of treating regenerated collagen fibers by the regenerated collagen fiber treatment method according to any one of <7> to <19>.

<22>
A headdress product comprising the modified regenerated collagen fiber according to any one of <1> to <6> as a constituent element.

<23>
The headdress product described in <22> selected from hair wigs, wigs, weaving, hair extensions, braided hair, hair accessories, and doll hair.

Examples 1 to 11, Comparative Examples 1 to 3
Using the composition shown in Table 1, regenerated collagen fibers were treated according to the following method, and various evaluations were performed. The pH of each composition was measured using a pH meter (manufactured by HORIBA, F-52) at room temperature (25° C.).

<Processing method>
1. Regenerated collagen fibers (*) 0.50g of hair strands with a length of 22cm are soaked in a container containing a fiber treatment agent in an amount that corresponds to the bath ratio shown in the table. It was immersed in a water bath (manufacturer: Toyo Seisakusho Co., Ltd./model number: TBS221FA) at the temperature shown and heated for the time shown in the table.
*: Regenerated collagen fibers manufactured by Kaneka were purchased in the form of commercially available extension products, and the fibers were cut and divided into hair bundles for evaluation. For this evaluation, we used extension products that are labeled as using 100% Ultima as the fiber type, are white with a color count of 30, and are straight in shape.
2. The container containing the hair tresses was removed from the water bath and allowed to come to room temperature.
3. Remove the hair strands from the container, rinse with running tap water at 30°C for 30 seconds, lather with evaluation shampoo for 60 seconds, rinse with running tap water at 30°C for 30 seconds, lightly dry with a towel, and remove the hair strands. was dried while combing with a hot air dryer (Tescom, Nobby White NB3000).

<Formulation of shampoo for evaluation>
Ingredients (mass%)
Sodium Laureth Sulfate 15.5
Lauramid DEA 1.5
EDTA-2Na 0.3
Phosphoric acid Amount to adjust to pH7 Ion exchange water Balance Total 100

<Increase in average elongation at break during fiber tension>
As an indicator of water resistance and elasticity (tenacity) when fibers are stretched, the average elongation at break, that is, the percentage of the original fiber length at which the fiber will break when it is stretched by tension, is The average value of multiple fibers (10 fibers) was used to determine whether or not this occurred. The evaluation was performed using the hair bundles immediately after being treated in the above <Treatment Method> according to the following procedure.
1. Ten fibers were cut from the root of the hair bundle. A 3 cm piece of fiber was collected from around the middle between the root and tip of each fiber, yielding a total of 10 pieces of 3 cm hair.
2. The fiber piece was set in "MTT690 Automatic Fiber Tensile Testing Machine" manufactured by DIA-STRON limited. Automatic measurement was started after the fibers were left immersed in water for 30 minutes, and the average elongation at break was determined while the fibers were immersed in water. The higher the numerical value, the higher the elasticity, the higher the tenacity, and the higher the durability.

According to the following formula, the average breaking elongation (A%) of the hair bundle after the treatment is based on the average breaking elongation (A%) when the fiber is pulled as it is (untreated; Comparative Example 1) cut from a commercially available product (untreated; Comparative Example 1), and the average breaking elongation (B %) increased from the untreated state (C%) is described in the table as "increase rate [%] of average elongation at break during fiber tension."
C (%) = B (%) - A (%)

<Increase in average breaking load during fiber tension>
The average breaking load during fiber tension was used as an index of water resistance during fiber tension. The evaluation was performed using hair bundles immediately after being treated by the above <treatment method>. Further, as the numerical value, the average value when evaluating multiple fibers (10 fibers) was used. The evaluation was performed according to the following procedure.
1. Ten fibers were cut from the root of the hair bundle. A 3 cm piece of fiber was collected from around the middle between the root and tip of each fiber, yielding a total of 10 pieces of 3 cm hair.
2. The fiber piece was set in "MTT690 Automatic Fiber Tensile Testing Machine" manufactured by DIA-STRON limited. Automatic measurement was started after leaving the fiber immersed in water for 30 minutes, and the breaking load when the fiber was stretched while immersed in water was determined. The higher the value, the firmer the material is, the more resistant it is to stretching by external force, and the more durable it is.

According to the following formula, the average breaking load (W 0 (gf)) of the hair bundle after the treatment is based on the average breaking load (W ₀ (gf)) when the fiber is pulled in the as-is condition (untreated; Comparative Example 1) cut from the commercially available product (untreated; Comparative Example 1). The extent to which W ₁ (gf)) increased from the untreated state (Y (gf)) is shown in the table as "increase in average breaking load during fiber tension [gf]".
Y (gf) = W ₁ (gf) - W ₀ (gf)

<Shrinkage rate when setting with high temperature iron>
The shrinkage rate when set with a high temperature iron was used as an index of heat resistance. The evaluation was performed using hair bundles immediately after being treated by the above <treatment method>. Further, as the numerical value, the average value when evaluating a plurality of fibers (5 fibers) was used. The evaluation was performed according to the following procedure.
1. <Treatment method> Five fibers were cut from the root of the hair bundle immediately after treatment and marked. After these treatments, the lengths of the five fibers were measured, and the average value was recorded (defining the length _L1 ). Next, the five treated fibers with these markings are bundled together between two separately prepared untreated regenerated collagen fiber bundles of 0.5 g (1 g in total) to form a new hair bundle (hereinafter referred to as a large hair bundle). A flat iron (manufactured by Miki Electric Industrial Co., Ltd./model number: AHI-938) set at 180°C was applied three times at a speed of 5 cm/sec to the entire large hair bundle.
2. After the ironing operation, take out the 5 marked treated fibers from the large hair bundle, measure the length of each of the 5 marked treated fibers, and record the average value (take the length L ₂ ). did.
3. The shrinkage rate when set with a high temperature iron was defined as S _dry = {1-(L ₂ /L ₁ )} x 100 [%]. The closer S _dry is to 0%, the less shrinkage due to dry heat occurs and the better the heat resistance is.

<Shrinkage rate when heating hot water>
The shrinkage rate when heated with hot water was used as an index of water resistance and heat resistance. The evaluation was performed using hair bundles immediately after being treated by the above <treatment method>. Further, as the numerical value, the average value when evaluating a plurality of fibers (5 fibers) was used. The evaluation was performed according to the following procedure.
1. Cut 5 fibers from the root of the hair bundle, record the average length of each fiber (length L ₁ ), and then soak in a 90℃ water bath (manufacturer: Toyo Seisakusho Co., Ltd. / model number: TBS221FA) ) and heated for 1 minute.
2. After the heating operation, take out the 5 fibers, lightly drain them with a towel, dry them at room temperature and humidity for 30 minutes, and then record the average length of each fiber again (the length is L ₂ ). did.
3. The shrinkage rate during heating with hot water was defined as S _wet = {1-(L ₂ /L ₁ )} x 100 [%]. The closer S _wet is to 0%, the less shrinkage due to moist heat occurs and the better the heat resistance is.

<Thermal shape memory ability>
Thermal shape memory ability was evaluated using hair bundles immediately after being treated by the above <treatment method>. In addition, when the value of the result of "I: Shape imparting (curl)" was 5% or less, it was considered that there was no effect, and subsequent processing and evaluation were not performed.
・I: Giving shape (curl)
1. A 22 cm long hair bundle containing 0.5 g of regenerated collagen fibers was wetted with tap water at 30°C for 30 seconds, and then the wet hair bundle was wrapped around a plastic rod with a diameter of 14 mm and fixed with a clip.
2. The hair bundle wrapped around the rod was immersed in a 60°C water bath (manufacturer: Toyo Seisakusho Co., Ltd./model number: TBS221FA) and heated for 1 minute.
3. The hair tresses were taken out of the water bath, immersed in water at 25°C for 1 minute, taken out of the water, and allowed to return to room temperature.
4. The hair bundle was removed from the rod, passed through the comb three times, and 3 minutes after being removed from the water, a photo was taken from the side while it was hanging.

(Evaluation criteria)
Assuming that the length of the untreated hair bundle is L ₀ (22cm) and the length of the hair bundle after treatment is L, the curl up rate = hair bundle length reduction rate (I) (%) is calculated according to the following formula. Defined as strength.
I=[(L ₀ -L)/L ₀ ]×100

・II: Reshaping (straight)
1. The hair bundle evaluated in I was passed through a comb to remove tangles, and then slid 6 times at a speed of 5 cm/sec with a flat iron (manufactured by Miki Electric Industrial Co., Ltd./model number: AHI-938) set at 180°C.
2. After rinsing with running tap water at 30°C for 30 seconds, lathering with evaluation shampoo for 60 seconds, rinsing with running tap water at 30°C for 30 seconds, and towel drying.
3. After hanging and air drying at 20°C and 65% RH for 12 hours, passing it through a comb, it was visually observed from the side while hanging.

(Evaluation criteria)
The straightening rate (ST) (%) determined according to the following formula was defined as the degree of straightening, where the length of the untreated hair bundle was L ₀ (22 cm) and the length of the hair bundle after treatment was L. When ST=100%, the hair bundle is completely straightened.
ST=[1-(L ₀ -L)/L ₀ ]×100

・III: Reshaping (curl)
1. The hair bundle evaluated in II was wetted with tap water at 30°C for 30 seconds, and then the wet hair bundle was wrapped around a plastic rod with a diameter of 14 mm and fixed with a clip.
2. The hair bundle wrapped around the rod was immersed in a 60°C water bath (manufacturer: Toyo Seisakusho Co., Ltd./model number: TBS221FA) and heated for 1 minute.
3. The hair tresses were taken out of the water bath, immersed in water at 25°C for 1 minute, taken out of the water, and allowed to return to room temperature.
4. The hair bundle was removed from the rod, passed through the comb three times, and 3 minutes after being removed from the water, a photo was taken from the side while it was hanging.

<Good surface feel>
To evaluate the surface feel, 5 expert panelists evaluated the smoothness of the touch using the following criteria using hair strands that had just been treated using the <treatment method>. This is the evaluation result.
(Evaluation criteria)
5: Extremely smooth texture compared to untreated fibers (Comparative Example 1) 4: Smooth texture compared to untreated fibers (Comparative Example 1) 3: Compared to untreated fibers (Comparative Example 1) Slightly smooth to the touch 2: Same texture as untreated fibers (Comparative Example 1) 1: Rough and squeaky, inferior to untreated fibers (Comparative Example 1)

<Suppression of coloring of fibers>
1. For each of the front and back sides of the hair bundle, the color was measured near the root, near the middle, and near the tip using a colorimeter (Konica Minolta Colorimeter CR-400), and the average value of a total of 6 points was taken as the colorimetric value ( L, a, b).
2. The degree of coloring was evaluated by ΔE*ab using an untreated hair bundle of color count 30 white (*) (Comparative Example 1) as a standard. In addition, the color was measured on the same day that the treatment was performed.

(*) Untreated hair bundles with a color count of 30 white Regenerated collagen fibers made by Kaneka were purchased in the form of commercially available extension products, and the fibers were cut and divided into hair bundles for evaluation. For this evaluation, we used extension products that are labeled as using 100% Ultima as the fiber type, are white with a color count of 30, and are straight in shape.
Note that these regenerated collagen fibers manufactured by Kaneka Co., Ltd. contain aluminum, and the aluminum content according to the above-mentioned analysis method was 6.8% by mass.

ΔE*ab is when the measured values of the untreated hair bundle with color count 30 white are (L ₀ , a ₀ , b ₀ ) and the measured values of the treated hair bundle are (L ₁ , a ₁ , b ₁ ) , [(L ₁ -L ₀ ) ² + (a ₁ -a ₀ ) ² +(b ₁ -b ₀ ) ² ] ^1/2 , and the coloring suppression effect was judged according to the following criteria.

5: ΔE*ab ≦ 5.0
4:5.0< ΔE*ab ≦ 10.0
3: 10.0< ΔE*ab ≦ 15.0
2: 15.0< ΔE*ab ≦ 20.0
1:20.0<ΔE*ab

<Quantification of benzoic acid>
The amount of benzoic acid contained in the regenerated collagen fibers after treatment was quantified by the following method and shown in the table as "Component (A) _{benzoic acid amount} " (not measured for Comparative Examples 2 and 3). .
・Reagents 6N hydrochloric acid: Titrant for volumetric analysis, manufactured by Kanto Kagaku Co., Ltd. Sodium acetate: Special grade, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. Acetic acid: Special grade, manufactured by Fuji Film Wako Pure Chemical Industries, Ltd. Acetonitrile: For LC/MS, manufactured by Kanto Kagaku Co., Ltd. Benzoin Sodium acid: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Ultrapure water: Ultrapure water production equipment Milli-Q manufactured water, manufactured by Millipore, quantitative method Cut the sample into small pieces, accurately weigh approximately 10mg, and add 3mL of 6N hydrochloric acid. The mixture was heated and dissolved at 50°C for 15 hours. After cooling, the solution was filtered and used as a sample solution. Separately, sodium benzoate was dissolved in a mobile phase and prepared to have a concentration of 0.1 to 100 μg/mL as benzoic acid, which was used as a standard solution for drawing a calibration curve. The sample solution and standard solution were tested by liquid chromatography, and the peak area of the sample solution and the peak area of the standard solution were measured.
・Measurement conditions Detector: UV-visible spectrophotometer Measurement wavelength: 230nm
Column: A stainless steel tube with an inner diameter of 21 mm and a length of 150 mm was filled with 5 μm octadecylsilylated silica gel for liquid chromatography.
Column temperature: Constant temperature around 40°C Mobile phase: About 0.68 g of sodium acetate and 0.91 g of acetic acid were dissolved by adding 750 mL of ultrapure water, and then 250 mL of acetonitrile was added and mixed.
・HPLC/UV conditions Equipment: UltiMate3000 system (manufactured by Thermo Fisher Scientific)
Column: L column 2 ODS5μm 2.1×150mm (Chemical Evaluation and Research Organization)
Column temperature: 40℃
Mobile phase: 20mM ammonium acetate 25% acetonitrile buffer Analysis time: 10 minutes Detector: DAD (diode array detector)
Detection wavelength: 230nm
Flow rate: 0.3mL/min (isocratic elution)
Injection volume: 10μL

<Aluminum quantitative method>
The amount of aluminum contained in the regenerated collagen fibers after the treatment was quantified by the following method and shown as "Component (B) _{Al amount} " in the table (not measured for Comparative Examples 2 and 3).
・Reagents Sulfuric acid: For precision analysis, manufactured by Fujifilm Wako Pure Chemicals Hydrochloric acid: For metal analysis, manufactured by Kanto Kagaku Co., Ltd. Sodium carbonate: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Boric acid: Special grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Aluminum standard Liquid: 1000mg/L for atomic absorption spectrometry, manufactured by Kanto Kagaku Co., Ltd. Ultrapure water: Ultrapure water production equipment Milli-Q manufactured water, manufactured by Millipore, Inc. Sample pretreatment method: Precisely weigh 0.1g of sample into a platinum crucible, and remove white smoke. After heating until no more white smoke was emitted, a few drops of sulfuric acid was added, and the mixture was heated again until no white smoke was emitted, followed by thorough ashing treatment in an electric furnace at 550°C. Thereafter, 1 g of an alkaline flux (sodium carbonate:boric acid=1:0.4) was added, and the mixture was melted in an electric furnace at 950°C. Cover with a watch glass, add 5 mL of ultrapure water and hydrochloric acid (6 mol/L), heat and dissolve on a hot plate at 70-80°C, and after cooling, adjust the volume to 50 mL with ultrapure water as the measurement solution. And so.
・Preparation of calibration curve solution A calibration curve solution of 0.1 to 20 mg/L was prepared using aluminum standard solution (1000 mg/L). An alkaline flux and hydrochloric acid were added to each solution to the same extent as the sample.
-Measurement Each element of the prepared sample was measured using an ICP emission spectrometer under the following conditions.
Analyzer: iCAP6500Duo (manufactured by Thermo Fisher Scientific)
Wavelength: Al 396.152nm
RF power: 1150W
Coolant gas flow rate: 12L/min
Nebulizer flow rate: 0.70L/min
Auxiliary gas: 0.5L/min
Pump flow rate: 50rpm

The hair bundles treated in the above examples can be used as extensions as they are by fixing them to the hair with pins or the like, and can exhibit sufficient performance even on a human head.

Claims

A modified regenerated collagen fiber containing 1.0% by mass or more of the following component (A) as benzoic acid in the regenerated collagen fiber.
(A) Benzoic acid or its salts
The modified regenerated collagen fiber according to claim 1, wherein the content of component (A) is 1.0 to 50% by mass as benzoic acid.
The modified regenerated collagen fiber according to claim 1, wherein the content of component (A) is 5.0 to 40% by mass as benzoic acid.
The modified regenerated collagen fiber according to any one of claims 1 to 3, further comprising the following component (B).
(B) Polyvalent metal, its salt or its complex
The modified regenerated collagen fiber according to claim 4, wherein component (B) is aluminum, a salt thereof, or a complex thereof.
A regenerated collagen fiber processing method comprising the following step (i).
Step (i) Step of immersing regenerated collagen fibers in a fiber treatment agent containing the following component (A) (A) Benzoic acid or its salt
The regenerated collagen fiber processing method according to claim 6, wherein the regenerated collagen fiber contains the following component (B).
(B) Polyvalent metal, its salt or its complex
The regenerated collagen fiber processing method according to claim 7, wherein component (B) is aluminum, a salt thereof, or a complex thereof.
A method for producing modified regenerated collagen fibers, comprising the step of treating regenerated collagen fibers by the regenerated collagen fiber treatment method according to any one of claims 6 to 8.
A method for producing a headdress product, comprising the step of treating regenerated collagen fibers by the regenerated collagen fiber treatment method according to any one of claims 6 to 8.
A headdress product comprising the modified regenerated collagen fiber according to any one of claims 1 to 5 as a constituent element.