JP6831365B2 - Manufacturing method of regenerated collagen fiber - Google Patents

Description

The present invention relates to a method for producing regenerated collagen fibers. More specifically, the present invention relates to a method for producing regenerated collagen fibers having suppressed gloss and thermal discoloration, which can be suitably used for hair, artificial fur and the like.

Since the regenerated collagen fiber is a protein fiber that retains a characteristic molecular structure derived from collagen, its texture, luster, and tactile sensation are similar to those of human hair, which is a natural protein fiber and has an extremely complicated fine structure. ing. Therefore, attempts have been made to use it as an animal hair-like fiber for hair fibers and artificial furs.

Regenerated collagen fibers are generally made from animal skin and bone, and are treated with alkali or enzyme to make collagen soluble in water, and then collagen soluble in water is extruded into an aqueous inorganic salt solution and spun. Manufactured. However, the regenerated collagen fiber thus obtained dissolves in water as it is, and therefore the heat resistance is lowered. Therefore, a water resistance treatment (water insolubilization treatment) is performed in order to impart water resistance and heat resistance. ..

As the fiber, a fiber having a weak luster may be required, and the performance is particularly strongly required as a fiber for hair. However, the regenerated collagen fiber has a stronger luster than the human hair fiber, and has a problem that when it is used as a fiber for hair, it tends to cause a discomfort in appearance. In order to solve this problem, an attempt has been made to suppress the gloss by making the cross-sectional shape of the fiber atypical (Y-shaped, S-shaped, C-shaped, etc.) (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-24586

However, the fiber produced by the method of Patent Document 1 has a problem that the quality such as tactile sensation and combing is impaired due to the influence of the cross-sectional shape. On the other hand, the inventor of the present application adds an additive to an aqueous solution containing solubilized collagen in the collagen stock solution preparation step, which is one step in the manufacturing process of regenerated collagen fibers, to improve the quality such as tactile sensation and combing. An attempt was made to suppress the gloss of the fibers without damaging them. However, in the process of examining this method, even if the gloss of the fiber can be suppressed by adding an additive, depending on the type of the additive to be added, the produced fiber becomes white and has a dead hair tone (opaque, whitish, dull). Color: white bokeh: low saturation), or the new challenge of being overly transparent compared to human hair, and / or thermal discoloration of the fibers when styling with a hot curling iron. It turned out that a new problem of (iron discoloration) could occur. The dead hair-like fibers do not have the appropriate transparency found in human hair and are the most disliked in appearance. Further, the above-mentioned phenomenon of iron discoloration has not been known so far, and is a problem first discovered by the present inventor. Any of these issues can be a major problem in product quality, especially when the fibers to be produced are light in color.

The present invention has been made in view of the above problems, has gloss and transparency similar to human hair, and maintains gloss and transparency even after being treated with a curling iron (that is, the above-mentioned iron discoloration). It is an object of the present invention to provide a method for producing regenerated collagen fiber (which suppresses a problem).

As a result of diligent studies in order to solve the above problems, the inventor of the present invention found collagen among the methods for producing regenerated collagen fibers having a collagen stock solution preparation step, a spinning step, a water resistance step, and a drying step. In the undiluted solution preparation process, an aqueous solution containing solubilized collagen and metal oxide is prepared as a collagen undiluted solution, and by applying this undiluted solution to the spinning process, a high-temperature hair iron that has gloss and transparency close to human hair can be obtained. We have found that a regenerated collagen fiber that is less susceptible to thermal discoloration can be obtained even during the styling used, and have reached the present invention.

The present invention is a method for producing a regenerated collagen fiber, which comprises a collagen stock solution preparation step, a spinning step, a water resistance step, and a drying step, among which, in the collagen stock solution preparation step, solubilized collagen and a metal are used as the collagen stock solution. Provided is a method for producing a regenerated collagen fiber, which comprises preparing an aqueous solution containing an oxide.

According to the present invention, it is possible to obtain a regenerated collagen fiber having a gloss and transparency similar to that of human hair and maintaining the gloss and transparency even after being treated with a curling iron.

In the above invention, it is preferable that the content of the metal oxide in the collagen stock solution is 0.05 to 3.00% by weight based on the total amount of the collagen and the metal oxide in the collagen stock solution preparation step.

In the above invention, it is preferable that the metal oxide is at least one oxide selected from the group consisting of aluminum oxide, zirconium oxide, titanium oxide, antimony trioxide, and silicon oxide.

According to the production method of the present invention, it is possible to obtain a regenerated collagen fiber having a gloss and transparency close to that of human hair and which is less susceptible to heat discoloration even when styling with a high-temperature curling iron. In particular, when producing light-colored regenerated collagen fibers, it is of great significance to obtain the above-mentioned effects.

It is a figure which shows the performance evaluation method of the regenerated collagen fiber in an Example and a comparative example.

The following embodiments further describe the present invention in accordance with the following embodiments, and the following embodiments describe the present invention and do not limit the present invention.

Hereinafter, as an example, the method for producing the regenerated collagen fiber of the present invention will be described.

The method for producing a regenerated collagen fiber of the present invention includes at least a collagen stock solution preparation step, a spinning step, a water resistance step, and a drying step, and these steps are carried out in this order.

(Collagen stock solution preparation process)
As the raw material of collagen used in the present invention, it is preferable to use a portion of the floor skin. The leather is obtained from fresh leather or salted rawhide obtained by slaughtering livestock animals such as cattle. Most of these floor skins are made of insoluble collagen fibers, but they are usually used after removing the fleshy part adhering to the network and removing the salt used for preventing putrefaction and deterioration.

Insoluble collagen fibers contain impurities such as lipids such as glyceride, phospholipids and free fatty acids, glycoproteins, and proteins other than collagen such as albumin. These impurities have a great influence on spinning stability, quality such as luster and elongation, and odor when fiberized. Therefore, for example, the fat content in the insoluble collagen fibers is hydrolyzed by lime pickling to loosen the collagen fibers, and then the leather treatment generally performed in the past such as acid / alkali treatment, enzyme treatment, solvent treatment, etc. is performed. It is preferable to apply and remove these impurities in advance.

The insoluble collagen subjected to the above-mentioned treatment is subjected to a solubilization treatment in order to cleave the crosslinked peptide portion. As a result, solubilized collagen is obtained. As a method for such solubilization treatment, a generally known alkaline solubilization method, enzyme solubilization method, or the like can be applied. Further, 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. As an improved method of the conventionally known alkali solubilization method, the method described in Japanese Patent Publication No. 46-15033 may be used.

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

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

A metal oxide is mixed with the obtained solubilized collagen to prepare an aqueous solution containing the solubilized collagen and the metal oxide to obtain a collagen stock solution to be used in the next spinning step. The main raw material of the collagen stock solution is collagen, and the proportion of collagen in the raw material of the collagen stock solution (solid content excluding water) is 50% by weight or more, preferably 70% by weight or more, and more preferably 80% by weight or more. preferable.

It is preferable to add, for example, an acid such as hydrochloric acid, acetic acid, or lactic acid and / or water to the aqueous solution to obtain a pH and concentration suitable for the next spinning step. The pH of the collagen stock solution is preferably 2 to 4.5, and the raw material concentration (solid content excluding water) in the collagen stock solution is preferably 1 to 15% by weight. The lower limit of the raw material concentration (solid content excluding water) in the collagen stock solution is preferably 2% by weight or more, and the upper limit is preferably 10% by weight or less.

It is preferable that the metal oxide is in the form of particles. The average particle size of the particulate metal oxide is not particularly limited, but is preferably 0.15 μm or more. When the average particle size is 0.15 μm or more, it is possible to more easily produce a regenerated collagen fiber having a gloss and transparency close to that of human hair and less susceptible to thermal discoloration when styling with a curling iron. The upper limit of the average particle size is not particularly limited, but it is preferably not less than the pore size (for example, 45 μm) of the filter used when filtering the collagen stock solution described later. As a result, it is possible to prevent the filter from being clogged when the collagen stock solution is filtered.

The amount of the metal oxide added is preferably such that the content of the metal oxide in the total amount of collagen and the metal oxide in the collagen stock solution is 0.05 to 3.00% by weight. When the content of the metal oxide is 0.05% by weight or more, 0.20% by weight or more, or 0.50% by weight or more, the effect of suppressing gloss is high, and the transparency is also moderately transparent like human hair. It is preferable because it can be adjusted. Further, when the content of the metal oxide is 3.00% by weight or less, 2.80% by weight or less, or 2.50% by weight or less, the hair does not become opaque, whitish and dull, and the hair does not have a dead hair tone. It is preferable because the transparency can be adjusted to an appropriate level.

The metal oxide referred to in the present invention is, for example, aluminum oxide, zirconium oxide, titanium oxide, antimony pentoxide, silicon oxide, zinc oxide, calcium oxide, silver oxide, copper (I) oxide, copper (II) oxide, iron oxide. (II), iron (III) oxide, triiron tetroxide, etc., but are not limited to these, and are also concepts that include so-called semi-metal oxides. Preferably, it is at least one oxide selected from the group consisting of aluminum oxide, zirconium oxide, titanium oxide, antimony trioxide, silicon oxide, zinc oxide, calcium oxide and silver oxide. More preferably, it is at least one oxide selected from the group consisting of aluminum oxide, zirconium oxide, titanium oxide, antimony trioxide, silicon oxide, zinc oxide and calcium oxide. Most preferably, it is at least one oxide selected from the group consisting of aluminum oxide, zirconium oxide, titanium oxide, antimony trioxide, and silicon oxide.

If necessary, the collagen aqueous solution may be defoamed under reduced pressure stirring or filtered to remove fine dust which is a water-insoluble matter. Further, if necessary, the collagen aqueous solution contains a stabilizer and a highly water-soluble substance for the purpose of improving mechanical strength, water resistance and heat resistance, improving spinnability, preventing coloring, preservatives, and the like. An appropriate amount of an additive such as a molecular compound may be blended.

(Spinning process)
Next, the collagen stock solution is discharged through, for example, a spinning nozzle or a slit, and then immersed in an aqueous inorganic salt solution to form regenerated collagen fibers. As the inorganic salt aqueous solution, for example, an aqueous solution of a water-soluble inorganic salt such as sodium sulfate, sodium chloride, or ammonium sulfate is used. Usually, the concentration of the inorganic salt in these aqueous inorganic salt solutions is adjusted to 10 to 40% by weight.

The pH of the aqueous inorganic salt solution is preferably adjusted to pH 2 to 13 by using, for example, a metal salt such as sodium borate or sodium acetate, hydrochloric acid, boric acid, acetic acid, sodium hydroxide or the like. The lower limit of the pH of the aqueous inorganic salt solution is more preferably 4 or more. The upper limit of the pH of the aqueous inorganic salt solution is more preferably 12 or less. When the pH of the aqueous inorganic salt solution is in the range of 2 to 13, the peptide bond of collagen is less likely to be hydrolyzed, and the desired fiber can be easily obtained.

The temperature of the aqueous inorganic salt solution is not particularly limited, but is usually preferably 35 ° C. or lower. When the temperature of the aqueous inorganic salt solution is 35 ° C. or lower, the soluble collagen is not denatured, the strength of the spun fiber does not decrease, and stable yarn production becomes easy. The lower limit of the temperature of the aqueous inorganic salt solution is not particularly limited, but it can usually be appropriately adjusted according to the solubility of the inorganic salt.

(Water resistant process)
The regenerated collagen fibers obtained as described above are subjected to water resistance treatment. As a result, water-insoluble regenerated collagen fibers can be obtained. In the present invention, the specific method of the water resistance treatment is not particularly limited, but for example, the regenerated collagen fiber may be immersed in an epoxy compound or a solution thereof to perform a water resistance treatment (crosslinking treatment).

The epoxy compound is not particularly limited, but a monofunctional epoxy compound can be preferably used. Specific examples thereof are not particularly limited, but for example, olefin oxides such as ethylene oxide, propylene oxide, butylene oxide, isobutylene oxide, octene oxide, styrene oxide, methylstyrene oxide, epichlorohydrin, epibromohydrin, and glycidol. Classes; glycidyl methyl ether, butyl glycidyl ether, octyl glycidyl ether, nonyl glycidyl ether, undecyl glycidyl ether, tridecyl glycidyl ether, pentadecyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, cresil glycidyl ether. Glycidyl ethers such as ether, t-butylphenyl glycidyl ether, dibromophenyl glycidyl ether, benzyl glycidyl ether, polyethylene oxide glycidyl ether; glycidyl esters such as glycidyl acrylate, glycidyl acetate, glycidyl acrylate, glycidyl methacrylate, glycidyl benzoate Includes glycidyl amides and the like.

The amount of the epoxy compound used is preferably 0.1 to 500 equivalents with respect to the amount of amino groups that can react with the epoxy compound in the regenerated collagen fiber. The lower limit is more preferably 0.5 equivalents or more, still more preferably 1 equivalent or more. The upper limit is more preferably 100 equivalents or less, still more preferably 50 equivalents or less. When the amount of the epoxy compound used is 0.1 to 500 equivalents, it is possible to sufficiently impart the insolubilizing effect to water to the regenerated collagen fiber, and it is also preferable in terms of industrial handling and the environment. The cross-linking treatment with the epoxy compound may be performed after the treatment with the zirconium salt described later.

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

The treatment temperature of the regenerated collagen fiber with the epoxy compound is preferably 50 ° C. or lower. When the treatment temperature is 50 ° C. or lower, the regenerated collagen fibers are not denatured, the strength of the obtained fibers is not lowered, and stable yarn production becomes easy.

Next, the regenerated collagen fiber may contain the zirconium salt by treating the regenerated collagen fiber with a zirconium salt. The regenerated collagen fiber can enhance water insolubility by containing a zirconium salt. The regenerated collagen fiber is also crosslinked with zirconium and becomes water-insoluble by treating it with a zirconium salt without performing the crosslinking treatment with an epoxy compound. The content of the zirconium salt converted to zirconium oxide (ZrO ₂ ) in the regenerated collagen fiber is preferably 12% by weight or more, more preferably 17% by weight or more, still more preferably 19% by weight or more. When the content of the zirconium salt in terms of zirconium oxide is 12% by weight or more, the heat resistance is relatively sufficient. The upper limit of the zirconium salt content may be set within a range in which the characteristics as a fiber can be maintained. The upper limit of the content of the zirconium salt in the regenerated collagen fiber is preferably 30% by weight or less, more preferably 27% by weight or less, still more preferably 25% by weight or less in terms of zirconium oxide.

The step of treating the regenerated collagen fiber with the zirconium salt is not particularly limited as long as it is a treatment capable of containing the zirconium salt in the regenerated collagen fiber. For example, the treatment can be performed by immersing the regenerated collagen fiber in an aqueous solution of a zirconium salt. By this treatment, the heat-resistant temperature of the hair iron of the regenerated collagen fiber finally obtained becomes 125 ° C. or higher, and the regenerated collagen fiber when wet is added to the elasticity, the wet touch feeling is improved, and the shape of the curl set etc. is given well. become. The zirconium salt is not particularly limited, and examples thereof include zirconium sulfate, zirconium acetate, and zirconium acetate. These zirconium salts can be used alone or in admixture of two or more.

In the present invention, converting to zirconium oxide means converting the weight of a zirconium compound to the weight of zirconium oxide having the same number of zirconium atoms. For example, 1 g of zirconium oxide corresponds to 2.3 g of zirconium sulfate, 2.7 g of zirconium acetate and 1.4 g of zirconium acidified. That is, 100 g of regenerated collagen fiber containing 2.3 g of zirconium sulfate becomes a regenerated collagen fiber containing 1% by weight of zirconium salt in terms of zirconium oxide.

The temperature of the aqueous solution of the zirconium salt is not particularly limited, but is preferably 50 ° C. or lower. When the liquid temperature of the aqueous solution of the zirconium salt is 50 ° C. or lower, the regenerated collagen fibers are not denatured. Inorganic salts such as sodium chloride, sodium sulfate, and potassium chloride are appropriately added to the aqueous solution of the zirconium salt in an amount of 1 to 20% by weight in order to prevent the zirconium salt from being rapidly absorbed into the regenerated collagen fibers and causing uneven concentration. It may be added so as to have the concentration of. Further, in order to improve the stability of the zirconium salt in water, an organic acid such as lactic acid or an organic acid salt such as sodium citrate may be appropriately added to the aqueous solution of the zirconium salt.

Next, the regenerated collagen fiber containing a zirconium salt may be treated with a phosphorus-based compound to contain the regenerated collagen fiber. At this time, the treatment is carried out so that the content of the phosphorus-based compound converted to phosphorus in the regenerated collagen fiber is preferably 2% by weight or more, more preferably 3% by weight or more, still more preferably 4% by weight or more. Moisture and heat resistance is improved when the regenerated collagen fiber contains 2% by weight or more of a phosphorus-based compound in terms of phosphorus. Therefore, shrinkage during wet heat treatment, which is generally performed when processing regenerated collagen fibers containing a zirconium salt into a headdress product, is suppressed, and processability is improved. Furthermore, it is possible to suppress shrinkage when styling a headdress product containing regenerated collagen fibers with a treatment, and solve the problem of changing the hairstyle. That is, in the present invention, the phosphorus compound exerts an effect of suppressing the shrinkage of the regenerated collagen fiber during the wet heat treatment, and functions as a shrinkage suppressing substance in the wet heat treatment. When the content of the phosphorus compound converted to phosphorus is 2% by weight or more, the moist heat resistance is good, the shrinkage rate during processing by moist heat treatment (wet heat treatment shrinkage rate) is lower than 10%, and the suppression of shrinkage is relatively sufficient. Is. The upper limit of the content of the phosphorus compound in the regenerated collagen fiber may be set within a range in which the characteristics as the fiber can be maintained. The upper limit of the content of the phosphorus compound in the regenerated collagen fiber is preferably 10% by weight or less in terms of phosphorus, more preferably 9% by weight or less, still more preferably 8% by weight or less.

The step of treating the regenerated collagen fiber with the phosphorus-based compound is not particularly limited as long as it is a treatment capable of containing the phosphorus-based compound in the regenerated collagen fiber. For example, it can be carried out by immersing the regenerated collagen fiber treated with a zirconium salt in an aqueous solution containing a phosphorus compound.

The phosphorus-based compound is not particularly limited, and is, for example, phosphoric acid, phosphate, phosphate derivative, phosphate derivative, diphosphate, diphosphate, diphosphate derivative, diphosphate derivative, metaphosphorus. Acids, metaphosphates, metaphosphate derivatives, metaphosphate derivatives, polyphosphates, polyphosphates, polyphosphate derivatives, polyphosphate derivatives, phosphonic acid (phosphite), phosphonates, phosphonic acid derivatives and phosphonates Derivatives can be mentioned. For example, examples of the phosphate include sodium dihydrogen phosphate, disodium hydrogen phosphate, diammonium hydrogen phosphate and the like. Examples of the phosphonic acid derivative include phenylphosphonic acid. Among these, disodium hydrogen phosphate, phosphonic acid, diammonium hydrogen phosphate, etc. are preferably used as phosphorus compounds from the viewpoint of being relatively inexpensive, easily available, powdery, and easy to handle including storage. Can be used. These phosphorus compounds can be used alone or in combination of two or more.

In the present invention, converting to phosphorus means converting the weight of a phosphorus compound into the weight of phosphorus having the same number of phosphorus atoms. For example, 1 g of phosphorus corresponds to 3.2 g of phosphoric acid, 3.9 g of sodium dihydrogen phosphate, 4.6 g of disodium hydrogen phosphate, and 4.3 g of phosphorus. It corresponds to disodium hydrogen phosphate, 2.6 g of phosphonic acid, and 5.1 g of phenylphosphonic acid. That is, 100 g of regenerated collagen fiber containing 3.2 g of phosphoric acid becomes a regenerated collagen fiber containing 1% by weight of a phosphorus compound in terms of phosphorus.

The temperature of the aqueous solution of the phosphorus compound is not particularly limited, but is preferably 70 ° C. or lower. When the liquid temperature of the aqueous solution of the phosphorus compound is 70 ° C. or lower, the regenerated collagen fibers are not denatured and the physical properties are not deteriorated.

In the present invention, the regenerated collagen fiber may be further treated with an aluminum salt to contain an aluminum salt. By including the aluminum salt, hair breakage after heat treatment with a curling iron is reduced. The content of the aluminum salt in the regenerated collagen fiber is preferably 0.5% by weight or more, more preferably 1% by weight or more, still more preferably 1% by weight or more in terms of aluminum oxide (Al ₂ O ₃ ). 3% by weight or more. The upper limit of the content of the aluminum salt in the regenerated collagen fiber is not particularly limited, but from the viewpoint of maintaining high heat resistance while suppressing hair breakage, it may be 17% by weight or less in terms of aluminum oxide. It is preferable, more preferably 10% by weight or less, still more preferably 8% by weight or less.

The treatment with an aluminum salt is not particularly limited, but can be performed at the same time as the treatment with a zirconium salt by using, for example, a treatment liquid obtained by adding an aluminum salt to an aqueous solution of a zirconium salt. The treatment can be carried out under the same conditions as when the aqueous solution of the zirconium salt is used, except that the aluminum salt is added to the aqueous solution of the zirconium salt. The aluminum salt is not particularly limited, and examples thereof include aluminum sulfate, aluminum chloride, and alum. These aluminum salts can be used alone or in combination of two or more.

(Drying process)
The water-insoluble regenerated collagen fibers thus obtained are then washed with water and / or oiled, if necessary, and then dried. The washing with water can be performed, for example, by washing with running water for 10 minutes to 4 hours. As the oil agent used for oiling, for example, an emulsion consisting of an amino-modified silicone, an epoxy-modified silicone, a polyether-modified silicone, or an oil agent composed of a pluronic-type polyether antistatic agent can be used. The temperature at the time of drying is preferably 100 ° C. or lower, more preferably 75 ° C. or lower.

Although the above description describes further treatment performed on the regenerated collagen fiber obtained by spinning as an example, in the present invention, such treatment is not particularly limited and does not affect the object of the present invention. All you need is.

In the present invention, the content of the zirconium salt converted to zirconium oxide and the content of the aluminum salt converted to aluminum oxide in the regenerated collagen fiber are as follows, that of zirconium (Zr) and aluminum (Al) in the fiber. After measuring the concentration, it can be calculated based on the oxide conversion. Further, in the present invention, the content of the phosphorus-based compound converted to phosphorus in the regenerated collagen fiber can be confirmed by measuring the concentration of phosphorus (P) in the fiber as described below.

[Method for measuring the concentration of Zr, Al and P in fiber]
<Pretreatment>
The regenerated collagen fiber is dried at 105 ° C. for 2 hours and used as a sample. Approximately 0.1 g of the sample is precisely weighed in a TFM (Teflon®) decomposition container, and sulfuric acid (Kanto Chemical Co., Ltd., ultra-high purity sulfuric acid), nitric acid (Kanto Chemical Co., Inc., ultra-high purity nitric acid), and hydrofluoric acid (manufactured by Kanto Chemical Co., Inc. (Kanto Chemical Co., Ltd., ultra-high-purity hydrofluoric acid) is added and pressure acid decomposition is performed with a microwave decomposition device, and the decomposition liquid is settled in pure water (electrical resistance of 3.0 Ω · cm or more) to 50 mL. , Dilute appropriately with pure water (electrical resistance of 3.0 Ω · cm or more) to prepare the measurement solution.

<Measurement method>
Absolute calibration using ICP emission spectroscopic analysis method (ICP emission spectroscopy analyzer "ICPS-8100" manufactured by Shimadzu Corporation) and Y (measurement wavelength: 371.029 nm) as the internal standard material for the concentration of each element in the sample. It was measured by the linear method. At the same time, a blank test was conducted. The measurement wavelengths of each element were Zr: 343.823 nm, Al: 396.153 nm, and P: 213.620 nm.

<Calculation method>
The concentration of each element in the fiber was calculated using the following formula. Concentration of each element in fiber (% by weight) = [ICP measurement value of sample (mg / L) -ICP measurement value of blank (mg / L)] x 50 (mL) x dilution ratio / [sample weight (g)) × 10000].

<Oxide conversion>
(1) The content of zirconium oxide was calculated using the following formula. Zirconium oxide content (% by weight) = concentration of Zr in fiber (% by weight) / molar mass of Zr (91.2 g / mol) x ₂ molar mass of ZrO (123.2 g / mol)
(2) The content of aluminum oxide was calculated using the following formula. Aluminum oxide content (% by weight) = concentration of Al in fiber (% by weight) / molar mass of Al (27.0 g / mol) x [Al ₂ O ₃ molar mass (102.0 g / mol) / 2].

From the viewpoint of heat resistance, the regenerated collagen fiber preferably has a hair iron heat resistant temperature of 125 ° C. or higher. From the viewpoint of being more excellent in heat resistance, the heat resistant temperature of the curling iron is preferably 130 ° C. or higher, more preferably 140 ° C. or higher, further preferably 150 ° C. or higher, and particularly preferably 160 ° C. or higher.

From the viewpoint of excellent moisture and heat resistance, the regenerated collagen fiber preferably has a wet heat treatment shrinkage rate of 10% or less. From the viewpoint of being more excellent in moist heat resistance, the wet heat treatment shrinkage rate is preferably 7% or less, more preferably 5% or less.

From the viewpoint of excellent water resistance, the regenerated collagen fiber preferably has a water absorption rate of 250% or less. From the viewpoint of being more excellent in water resistance, the water absorption rate of the regenerated collagen fiber is more preferably 220% or less, and further preferably 150% or less.

From the viewpoint of maintaining the strength of the regenerated collagen fiber, the tensile strength is preferably 1.0 CN / dtex or more, more preferably 1.1 CN / dtex or more, and further preferably 1.2 CN / dtex. It is more than dtex.

The regenerated collagen fiber of the present invention can be suitably used for hair fiber and blanket fiber, especially when it is light in color and has excellent heat resistance and moisture heat resistance. It can also be suitably used as a fiber used for surgical sutures, catgut, non-woven fabrics, paper and the like.

According to the present invention, a collagen stock solution containing a metal oxide is prepared in a collagen stock solution preparation step, which is one step in the production process of regenerated collagen fibers, and the collagen stock solution containing a metal oxide is subjected to a spinning step to have a gloss and transparency similar to human hair. It is also possible to produce regenerated collagen fibers that maintain gloss and transparency even after being treated with a hair iron. Such regenerated collagen fibers can be suitably used as fibers for hair.

It should be noted that, in the undiluted solution process, which is one step of the regenerated collagen fiber manufacturing process, the regenerated collagen fiber having a gloss similar to that of human hair can be produced by adding an organic additive instead of the above metal oxide. Although it may be possible, iron discoloration cannot be suppressed. However, after adding the metal oxide of the present invention, an organic additive may be appropriately added to the extent that the effects of the present application are not impaired. The organic additive may be, for example, oleic acid, epoxidized soybean oil, polyvinyl acetate resin (PVAc) or the like.

Next, the present invention will be described in more detail based on Examples, but the present invention is not limited to such Examples. In all the following Examples and Comparative Examples, the regenerated collagen fibers were prepared as follows.

(Production Example 1) Preparation of collagen stock solution (stock solution preparation step)
Collagen was solubilized with alkali using cow leather as a raw material. The additive described in each Example or Comparative Example was added to 1200 g of the obtained solubilized collagen (collagen content 180 g), dissolved in a lactic acid aqueous solution, and the pH was 3.5 and the solid content concentration (consisting of collagen and the additive) was 7. The collagen solution was adjusted to be 5.5% by weight.

(Manufacturing Example 2) Preparation of regenerated collagen fiber (spinning process)
The collagen aqueous solution obtained in Production Example 1 was subjected to a stirring defoaming treatment under reduced pressure, transferred to a piston-type spinning stock solution tank, and further allowed to stand under reduced pressure to defoam. Next, the defoamed collagen aqueous solution was extruded with a piston, then quantitatively sent by a gear pump and filtered through a sintered filter having a pore size of 45 μm. Next, a coagulation bath (25 ° C.) containing 17% by weight of sodium sulfate adjusted to pH 11 with sodium hydrogen carbonate and sodium hydroxide by passing the filtered solubilized collagen aqueous solution through a spinning nozzle having a pore size of 0.212 mm and a pore size of 275. Regenerated collagen fibers were obtained by discharging at a spinning speed of 5 m / min.

(Manufacturing Example 3) Water resistance treatment (water resistance process)
The regenerated collagen fiber obtained in Production Example 2 was immersed in an aqueous solution containing 17% by weight of sodium sulfate, 0.02% by weight of sodium hydroxide, and 0.83% by weight of epichlorohydrin at 25 ° C. for 5 hours, and then immersed. Further, it was immersed at 43 ° C. for 3.5 hours and treated with an epoxy compound. Next, after washing the obtained regenerated collagen fiber with water, zirconium sulfate adjusted to pH 4.0 with sodium hydroxide was 2.00% by weight in terms of ZrO ₂ , and aluminum sulfate was 0.40% by weight in terms of Al ₂ O ₃ . It was immersed in a treatment bath containing 0.56% by weight of citric acid monohydrate for 6 hours. Next, the regenerated collagen fibers treated with the zirconium salt and the aluminum salt were washed with water and then immersed in a treatment bath (pH 11.0) containing 5.0% by weight of disodium hydrogen phosphate for 6 hours to make the regenerated collagen fibers water-insoluble. Got

(Manufacturing example 4) Oil agent / drying process (drying process)
The water-insoluble regenerated collagen fiber obtained in Production Example 3 is immersed in a bathtub filled with an oil agent consisting of an emulsion of amino-modified silicone and an oil-based antistatic agent to attach the oil agent, and then a soaking air dryer at 70 ° C. is used. Used to dry under tension.

[Measurement method of average particle size of metal oxide]
For the average particle size of the metal oxide, the particle size distribution of the metal oxide was measured using a laser diffraction method, and the average particle size expressed by the median size was obtained from this particle size distribution. For the measurement of the particle size distribution by the laser diffraction method, a laser diffraction / scattering type particle size distribution measuring device LA-950 (manufactured by HORIBA, Ltd.) was used.

[Performance evaluation of regenerated collagen fiber]
The gloss, iron discoloration, and transparency of the regenerated collagen fibers were evaluated. The specific evaluation method and scale at that time are as follows.

<Evaluation environment>
As shown in FIG. 1, the gloss, iron discoloration, and transparency are judged by separating the sample from the D65 fluorescent lamp (Toshiba color comparison / inspection D65 fluorescent lamp, D-EDL-D65) light source by 15 cm and reflecting light of 45. The sample was visually observed at a position of ° and evaluated based on the following evaluation criteria.

In the ironing treatment, the fibers are well opened and then bundled with a total fineness of about 10,000 dtex. The ends of the fiber bundles were pinched with a hair iron adjusted to 180 ° C. for 5 seconds, and the degree of discoloration was evaluated according to the evaluation criteria described later.

<Evaluation criteria>

(Example 1)
5.20 g of Lightstar LA-S263 (Nissan Chemical Industries, Ltd., silicon oxide (SiO ₂ ) particles, solid content concentration 26.0%, average particle diameter 0.30 μm) in 1200.00 g of solubilized collagen (collagen content 180.00 g) (Silicone oxide 1.352 g) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Content of metal oxide = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 1.352 / (180.00 + 1.352) x 100 = 0.75%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was first grade, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 2)
2.25 g (Nissan Chemical Industries, Ltd., silicon oxide (SiO ₂ ) particles, solid content concentration 40.5%, average particle diameter 0.41 μm) to 1200.00 g of solubilized collagen (collagen content 180.00 g) (0.911 g) of silicon oxide was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Metal oxide content = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 0.911 / (180.00 + 0.911) x 100 = 0.50%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 2, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 3)
5.90 g of PC-7T1082 (Sumika Color Co., Ltd., silicon oxide (SiO ₂ ) particles, solid content concentration 23.2%, average particle diameter 0.69 μm) in solubilized collagen 1200.00 (collagen content 180.00) (Silicone oxide 1.369 g) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Content of metal oxide = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 1.369 / (180.00 + 1.369) x 100 = 0.75%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was first grade, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 4)
5.20 g of Lightstar LA-S26 (Nissan Chemical Industries, Ltd., silicon oxide (SiO ₂ ) particles, solid content concentration 26.0%, average particle diameter 0.70 μm) in 1200.00 g of solubilized collagen (collagen content 180.00 g) (Silicone oxide 1.352 g) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Content of metal oxide = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 1.352 / (180.00 + 1.352) x 100 = 0.75%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 2, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 5)
1.20 g of TITONE SA-1 (manufactured by Sakai Chemical Co., Ltd., titanium oxide (TiO ₂ ) particles, solid content concentration 7.50%, average particle diameter 0.15 μm) in 1200.00 g of solubilized collagen (collagen content 180.00 g) (Titanium oxide is 0.090 g) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Content of metal oxide = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 0.090 / (180.00 + 0.090) x 100 = 0.05%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was first grade, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 6)
4.90 g of TITONE GTR-100 (manufactured by Sakai Chemical Co., Ltd., titanium oxide (TiO ₂ ) particles, solid content concentration 7.50%, average particle diameter 0.26 μm) in 1200.00 g of solubilized collagen (collage content 180.00 g) (Titanium oxide is 0.368 g) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Metal oxide content = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 0.368 / (180.00 + 0.368) x 100 = 0.20%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 0, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 7)
Al ₂ O ₃ 1.5 μm (manufactured by Wako Pure Chemical Industries, Ltd., aluminum oxide (Al ₂ O ₃ ) particles, solid content concentration 7.50%, average particle diameter 1.) in 1200.00 g of solubilized collagen (collagen content 180.00 g). 18.20 g (1.565 g of aluminum oxide) was mixed with 50 μm). The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Content of metal oxide = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 1.365 / (180.00 + 1.365) x 100 = 0.75%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 0, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 8)
12 solubilized collagen 1200.00 g (collagen content 180.00 g) and Y-10 (Nissan Chemical Industries, Ltd. antimony pentoxide (Sb ₂ O ₅ ) particles, solid content concentration 44.0%, average particle diameter 0.20 μm) .65 g (5.566 g of antimony trioxide) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Content of metal oxide = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 5.566 / (180.00 + 5.566) x 100 = 3.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was first grade, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 9)
3.20 g (Made by Fuso Chemical Co., Ltd., silicon oxide (SiO ₂ ) particles, solid content concentration 28.0%, average particle size 0.20 μm) to 1200.00 g of solubilized collagen (collagen content 180.00 g) 0.896 g of silicon oxide) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Metal oxide content = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 0.896 / (180.00 + 0.896) x 100 = 0.50%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 2, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Example 10)
4.85 g (manufactured by Fuso Chemical Co., Ltd., silicon oxide (SiO ₂ ) particles, solid content concentration 28.0%, average particle diameter 0.20 μm) in 1200.00 g of solubilized collagen (collagen content 180.00 g) 1.358 g of silicon oxide) was mixed. The amount of the additive (metal oxide) added is expressed by the content of the metal oxide with respect to the total amount of collagen and the metal oxide in the collagen stock solution, and is calculated by the following formula.

Content of metal oxide = additive (metal oxide) / (collagen + additive (metal oxide)) x 100 (%) = 1.358 / (180.00 + 1.358) x 100 = 0.75%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 2, and good results were obtained in all of gloss, transparency, and iron discoloration.

(Comparative Example 1)
Add a certain amount of lactic acid aqueous solution and water to 1200.00 g of solubilized collagen (collagen content 180.00 g) and stir with a kneader so that the pH is 3.5 and the solid content concentration (collagen) is 7.5%. Was prepared.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The finally obtained regenerated collagen fiber was evaluated as having a gloss of 5th grade and a transparency of transparency. The iron discoloration was first grade, and the iron discoloration was good, but the gloss was very strong and the transparency was high.

(Comparative Example 2)
9.470 g of oleic acid (manufactured by NOF CORPORATION) was mixed with 1200.00 g of solubilized collagen (collagen content 180.00 g). The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 9.470 / (180.00 + 9.470) x 100 = 5.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 4, and the results showed that the iron discoloration was remarkably observed although the gloss and transparency were good.

(Comparative Example 3)
9.470 g of epoxidized soybean oil was mixed with 1200.00 g of solubilized collagen (180.00 g of collagen content). The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 9.470 / (180.00 + 9.470) x 100 = 5.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 3, and the iron discoloration was observed although the gloss and transparency were good.

(Comparative Example 4)
80.00 g (20.000 g of polyvinyl acetate resin) of polyvinyl acetate (PVAc) emulsion (manufactured by Showa Denko, solid content concentration 25.0%) is mixed with 1200.00 g of solubilized collagen (collagen content 180.00 g). did. The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 20.000 / (180.00 + 20.000) x 100 = 10.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was evaluated as grade 3, and the transparency was evaluated as opaque. The iron discoloration was grade 4, and the gloss was good but the transparency was low, and the result was that the iron discoloration was remarkably observed.

(Comparative Example 5)
A mixture of 1200.00 g of solubilized collagen (180.00 g of collagen) and 37.90 g of polyvinyl acetate (PVAc) emulsion (manufactured by Showa Denko, solid content concentration 25.0%) (9.475 g of polyvinyl acetate resin). did. The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 9.475 / (180.00 + 9.475) x 100 = 5.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 4, and the transparency was standard. The iron discoloration was grade 4, and the transparency was good, but the gloss was strong, and the iron discoloration was remarkably observed.

(Comparative Example 6)
133.40 g (20.010 g of polyacrylamide resin) of Polystron 117 (manufactured by Arakawa Chemical Industries, Ltd., solid content concentration 15.0%) was mixed with 1200.00 g of solubilized collagen (collagen content 180.00 g). The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 20.010 / (180.00 + 20.010) x 100 = 10.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The finally obtained regenerated collagen fiber was evaluated as having a gloss of 5th grade and a transparency of transparency. The iron discoloration was first grade, and the iron discoloration was good, but the gloss was very strong and the transparency was high.

(Comparative Example 7)
800.00 g (20.000 g of polyamide polyamine resin) of Alafix 255 (manufactured by Arakawa Chemical Industries, Ltd., solid content concentration 25.0%) was mixed with 1200.00 g of solubilized collagen (collagen content 180.00 g). The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 20.000 / (180.00 + 20.000) x 100 = 10.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The finally obtained regenerated collagen fiber was evaluated as having a gloss of 5th grade and a transparency of transparency. The iron discoloration was first grade, and the iron discoloration was good, but the gloss was very strong and the transparency was high.

(Comparative Example 8)
18.20 g of BARIFINE BF-20 (manufactured by Sakai Chemical Co., Ltd., barium sulfate particles, solid content concentration 7.50%, average particle diameter 0.03 μm) to 1200.00 g of solubilized collagen (collagen content 180.00 g) 1.365 g) was mixed. The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 1.365 / (180.00 + 1.365) x 100 = 0.75%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The finally obtained regenerated collagen fiber was evaluated as having a gloss of 5th grade and a transparency of transparency. The iron discoloration was first grade, and the iron discoloration was good, but the gloss was very strong and the transparency was high.

(Comparative Example 9)
74.20 g of BARIFINE BF-20 (manufactured by Sakai Chemical Co., Ltd., barium sulfate particles, solid content concentration 7.50%, average particle diameter 0.03 μm) in 1200.00 g of solubilized collagen (collagen content 180.00 g) 5.565 g) was mixed. The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 5.565 / (180.00 + 5.565) x 100 = 3.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The finally obtained regenerated collagen fiber was evaluated as having a gloss of grade 5 and a transparency of transparency. The iron discoloration was first grade, and the iron discoloration was good, but the gloss was very strong and the transparency was high. In addition, white spots were observed on the surface of the regenerated collagen fiber.

(Comparative Example 10)
126.30 g of BARIFINE BF-20 (manufactured by Sakai Chemical Co., Ltd., barium sulfate particles, solid content concentration 7.50%, average particle diameter 0.03 μm) to 1200.00 g of solubilized collagen (collagen content 180.00 g) 9.473 g) was mixed. The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 9.473 / (180.00 + 9.473) x 100 = 5.00%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The finally obtained regenerated collagen fiber was evaluated as having a gloss of 5th grade and a transparency of transparency. The iron discoloration was grade 0, and the iron discoloration was good, but the gloss was very strong and the transparency was high. In addition, white spots were observed on the surface of the regenerated collagen fiber.

(Comparative Example 11)
1.88 g of Variace B-35 (barium sulfate particles, solid content concentration 72.20%, average particle diameter 0.30 μm) of 1200.00 g of solubilized collagen (collagen content 180.00 g) (barium sulfate is 1.357 g) was mixed. The amount of the additive added is expressed as a ratio to the total solid content (total of collagen and the additive) in the collagen stock solution, and is calculated by the following formula.

Addition amount = additive / (collagen + additive) x 100 (%) = 1.357 / (180.00 + 1.357) x 100 = 0.75%
Further, a certain amount of lactic acid aqueous solution and water were added and stirred with a kneader to prepare a collagen stock solution so that the pH was 3.5 and the solid content concentration (consisting of collagen and additives) was 7.5%.

The obtained collagen stock solution was treated by the method described in Production Examples 2 to 4 to obtain regenerated collagen fibers.

The gloss of the finally obtained regenerated collagen fiber was grade 3, and the transparency was standard. The iron discoloration was grade 4, and the gloss and transparency were good, but the iron discoloration was remarkably observed.

The results of Examples 1 to 10 and Comparative Examples 1 to 11 are shown in Table 4 below. The item of "aggregates" in Table 4 indicates whether or not a granular substance such as black spots or white spots is contained by observing the regenerated collagen fibers in the above evaluation environment.

The "amount of metal oxide" in Table 4 is the weight% of the metal oxide in the examples, but is not a metal oxide in the comparative example, but is shown as the weight% of each additive added.

As can be seen from Table 4, when metal oxide is added to the collagen stock solution, regenerated collagen fibers that are similar in gloss and transparency to human hair and are not susceptible to thermal discoloration even when styling with a high-temperature curling iron are obtained. Be done. When organic additives such as oleic acid, epoxidized soybean oil, and PVAc are added to the collagen stock solution, gloss is suppressed (for example, Comparative Examples 2 to 4), but iron discoloration cannot be suppressed. Also, when an inorganic additive other than metal oxide, such as barium sulfate, is added to the collagen stock solution, good results cannot be obtained in all of gloss, transparency, and iron discoloration, and white spots occur on the regenerated collagen fiber. Sometimes.

Claims (2)

A method for producing regenerated collagen fibers
It includes a collagen stock solution preparation step, a spinning step, a water resistance step, and a drying step, among which, in the collagen stock solution preparation step, a metal oxide is mixed with the solubilized collagen to contain the solubilized collagen and the metal oxide. By preparing an aqueous solution, a collagen stock solution to be used in the next spinning process can be obtained.
The solubilized collagen is obtained by lime-pickling the bedding of a domestic animal, hydrolyzing the fat content in the insoluble collagen fibers, loosening the collagen fibers, and then treating at least one of acid / alkali treatment, enzyme treatment, and solvent treatment. It was obtained by subjecting it to treatment and then solubilizing it by an alkali solubilization method and / or an enzyme solubilization method.
In the collagen stock solution preparing step, the content of the metal oxide in the total of the collagen and the metal oxide in the collagen stock solution is 0.05 to 3.00% by weight.
The solid content concentration in the collagen stock solution is 1 to 15% by weight.
The ratio of collagen in the solid content of the collagen stock solution is 50% by weight or more.
A method for producing a regenerated collagen fiber, wherein the pH of the collagen stock solution is 2 to 4.5 . The method for producing a regenerated collagen fiber according to claim 1 , wherein the metal oxide is at least one oxide selected from the group consisting of aluminum oxide, zirconium oxide, titanium oxide, antimony trioxide, and silicon oxide.

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