JP2022012957A - Biodegradable regenerated cellulose fiber and manufacturing method thereof, and fiber structure using the same - Google Patents

Abstract

To provide a manufacturing method of a biodegradable rayon fiber with less decrease in hardness property and high biodegradability, and a fiber structure using the same.SOLUTION: A biodegradable rayon fiber includes a regenerated cellulose and a non-crosslinkable protein, the regenerated cellulose and the non-crosslinkable protein being homogeneously dispersed. In a manufacturing method of a biodegradable rayon fiber, a regenerated cellulose liquid is blended with a component involving a non-crosslinkable protein solution to obtain a spinning solution, wherein at least the regenerated cellulose liquid and the non-crosslinkable protein solution are blended right before a spinning nozzle, then spun.SELECTED DRAWING: Figure 3

Description

The present invention relates to a highly biodegradable regenerated cellulose fiber, a method for producing the same, and a fiber structure using the same.

Regenerated cellulose fiber obtained by regenerating cellulose such as pulp has a soft texture, high drape, and hygroscopicity, so it is used for innerwear, ordinary innerwear, general clothing, women's clothing, and bedding fabrics that utilize hygroscopic heat generation. , Interior fabrics, vehicle fabrics, interlinings, medical hygroscopic materials, etc. The material form is used in various forms such as cotton, thread, woven fabric, knitting, non-woven fabric, and braid. As a prior art, Patent Document 1 prepares a solution of cellulose and a protein having a molecular weight of 50,000 or more or a natural substance containing such a protein, and spins the fiber from this solution to produce an aminated regenerated cellulose fiber. Has been proposed. Patent Document 2 proposes that two or more kinds of viscose spinning solutions are mixed and spun by a static mixer immediately before a spinning nozzle to obtain a fancy yarn. Patent Document 3 proposes arranging starch in the center of viscose rayon fiber to impart biodegradability. The applicants propose in Patent Documents 4 and 5 that a crosslinked protein is mixed with a rayon spinning solution to improve the dyeability (Patent Document 4) and to produce a filament (Patent Document 5).

Japanese Unexamined Patent Publication No. 8-170220 Japanese Unexamined Patent Publication No. 9-256222 Japanese Unexamined Patent Publication No. 11-124721 Japanese Unexamined Patent Publication No. 2004-149953 Japanese Unexamined Patent Publication No. 2007-039836

However, Patent Documents 1, 2, 4 and 5 do not have a problem of increasing the biodegradability of rayon fiber, and Patent Document 3 has a decrease in strength because starch is arranged in the center of viscose rayon fiber. There was a problem that it would end up.
The present invention provides a biodegradable regenerated cellulose fiber having little deterioration in strength and high biodegradability, a method for producing the same, and a fiber structure using the same.

The present invention is a biodegradable regenerated cellulose fiber, which is a biodegradable regenerated cellulose fiber containing cellulose and a non-crosslinked protein, wherein the cellulose and the non-crosslinked protein are uniformly dispersed.

In the method for producing a biodegradable regenerated cellulose fiber of the present invention, when a stock solution containing cellulose and a component containing a non-crosslinked protein solution are mixed to prepare a spinning solution, at least the stock solution containing cellulose and the non-crosslinked protein solution are used. It is characterized in that it is mixed immediately before the spinning nozzle and then spun.

The fiber structure of the present invention is characterized by containing the above-mentioned biodegradable regenerated cellulose fiber.

In the biodegradable regenerated cellulose fiber of the present invention, since cellulose and the non-crosslinked protein are homogeneously dispersed, the strength and physical characteristics are less likely to decrease, and the biodegradability can be improved. When the biodegradability is increased, disposal becomes easy, the global environment is not adversely affected, and in medical applications and the like, it is possible to provide a fiber structure in which the decomposition period in a living body is controlled.

FIG. 1 is an optical micrograph (magnification of 2000 times) of the side surface of the rayon fiber obtained in Example 1 after differential dyeing. FIG. 2 is a graph of biodegradability data (biochemical oxygen demand: BOD) of Examples and Comparative Examples of the present invention. FIG. 3 is a graph of biodegradability data (decomposition degree) of Examples and Comparative Examples of the present invention.

The present invention is a biodegradable regenerated cellulose fiber obtained by regenerating cellulose. Regenerated cellulose includes viscose rayon, cupra, polynosic, solvent-spun cellulose and the like made from natural wood pulp. Of these, viscose rayon is preferable from the viewpoint of using a spinning stock solution (viscose solution) which is superior in biodegradability to other regenerated cellulose and suitable for mixing non-crosslinked proteins. Cellulose and non-crosslinked protein are uniformly mixed. Since the non-crosslinked protein is dispersed as fine micelles in the cellulose component and covered with a cellulose membrane, it does not fall off from the regenerated cellulose fiber by washing or the like. The state in which the cellulose and the non-crosslinked protein are uniformly dispersed can be determined by staining the non-crosslinked protein by differential staining and observing the presence or absence of color unevenness, the interface state between the cellulose and the protein, and the like.

When the biodegradable regenerated cellulose fiber is a two-component system of cellulose and non-crosslinked protein, the non-crosslinked protein is preferably added in a proportion of 5 to 50 parts by mass, more preferably when the cellulose is 100 parts by mass. It is 8 to 35 parts by mass, more preferably 10 to 30 parts by mass. This makes it possible to increase the biodegradability without significantly reducing the fiber strength. The non-crosslinked protein can enhance the orientation of the regenerated cellulose fiber and prevent a decrease in strength.

The biodegradable regenerated cellulose fiber may further contain polyethylene glycol. Adding polyethylene glycol can improve flexibility and texture. When the amount of regenerated cellulose is 100 parts by mass, the polyethylene glycol is preferably added in a proportion of 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, and further preferably 4 to 7 parts by mass.

The non-crosslinked protein before mixing with cellulose is preferably a water-soluble protein. When it is water-soluble, it is easy to disperse in the spinning liquid, and it is easy to disperse as fine micelles in the cellulose component. After being formed into rayon fibers and then heated, the water-soluble protein is thermoset and incorporated into micromicellars, so that it does not desorb.

The non-crosslinked protein is preferably an alkali-soluble protein that is soluble in the pH range of 8 to 12. As a result, it is easy to disperse in the spinning liquid, and it is easy to disperse as fine micelles in the cellulose component. Non-bridged proteins that can be used in the present invention include, for example, globular proteins such as milk protein (casein), corn protein (zein), peanut protein (arachin), soybean protein (glycinin), collagen, silk fiber. Examples thereof include fibrous proteins such as fibroin and animal hair fiber (keratin), and water-soluble proteins such as gelatin (gelatin), and the number average molecular weight is preferably 9000 or more and less than 50,000. A more preferable number average molecular weight is 18,000 to 35,000. Further, the non-crosslinked protein is preferably gelatin, and its number average molecular weight is preferably 18,000 to 35,000. Gelatin can be highly biodegradable, and if it has the molecular weight, it is incorporated into the cellulose component as micromicelles and is maintained in a state where it is difficult to be detached. The molecular weight of gelatin can be measured by GPC (Gel Permeation Chromatography) by high performance liquid chromatography. As an example, the column is made by connecting two AsahiPak GS-620, the eluent is 0.1 M phosphate buffer (pH 6.8), the flow velocity is 1.0 mL / min, the sample is 0.1 mL of 0.2% aqueous solution, and the temperature is By detecting at 50 ° C and 230 nm using an ultraviolet detector, the number average molecular weight is 35,000, the weight average molecular weight is 9,100, and the peak top molecular weight is 22,000. The raw material of gelatin that can be used in the present invention is not particularly limited, and examples thereof include fish scale, fish skin, beef bone, cowhide, pork bone, and pork skin.

The number average molecular weight of polyethylene glycol is preferably 200 to 7500, more preferably 600 to 4000, and even more preferably 1000 to 2000. This makes it difficult to separate from the regenerated cellulose fiber.

In the method for producing a biodegradable regenerated cellulose fiber of the present invention, when a stock solution containing cellulose and a component containing a non-crosslinked protein solution are mixed to prepare a spinning solution, at least the stock solution containing cellulose and the non-crosslinked protein solution are spun. After mixing just before the nozzle, spin. This prevents the non-crosslinked protein solution from deteriorating and can be uniformly dispersed and mixed with the undiluted solution containing cellulose. As a method of mixing immediately before the spinning nozzle, mixing by an in-line mixing means is preferable. Specific examples of the in-line mixing means include mixing with a static mixer.

The non-crosslinked protein solution preferably has a pH in the range of 4-9. More preferably, the pH is 5-8. When the pH is within the above range, the non-crosslinked protein can be prevented from being altered and uniformly dispersed and mixed with the spinning solution. To adjust the pH of the non-crosslinked protein solution within the above range, for example, the non-crosslinked protein can be obtained by dissolving it in a solvent such as water without adding a strong alkaline solution having a pH of 11 or more.

When polyethylene glycol is contained in the biodegradable regenerated cellulose fiber of the present invention, a component in which a non-crosslinked protein solution and polyethylene glycol are mixed in advance and a stock solution containing cellulose are mixed immediately before the spinning nozzle and then spun. do.

The mixed solution containing the non-crosslinked protein and the component containing polyethylene glycol is preferably in the range of pH 4-9. More preferably, the pH is 5-8. When the pH is within the above range, the non-crosslinked protein can be prevented from being altered and uniformly dispersed and mixed with the spinning solution. To adjust the pH of the mixed solution containing the non-crosslinked protein solution and the component containing polyethylene glycol within the above range, for example, the non-crosslinked protein and polyethylene glycol can be adjusted without adding a strong alkaline solution having a pH of 11 or higher. It can be obtained by dissolving it in a solvent such as water.

The biodegradable regenerated cellulose fiber of the present invention can be produced by a known method for producing regenerated cellulose fiber, except that a mixed solution of non-crosslinked protein, polyethylene glycol and the like is added to a spinning solution containing cellulose. As the spinning solution, viscose rayon fiber containing viscose can be used, and in the case of cupra, a solution of cellulose in a copper ammonium solution can be used. In the case of solvent-spun cellulose (lyocell: trade name), a solution in which cellulose is dissolved in a solvent can be used.

When the regenerated cellulose fiber is a rayon fiber, it can be produced by mixing the mixed solution with the viscose stock solution immediately before the spinning nozzle, extruding it from the nozzle into a spinning bath, spinning it, and solidifying and regenerating it.

As the viscose stock solution, for example, a viscose stock solution containing 7 to 10% by mass of cellulose, 5 to 8% by mass of sodium hydroxide, and 2 to 3.5% by mass of carbon disulfide may be prepared and used.

As the (spinning) nozzle, for example, a circular nozzle having 1000 to 20000 holes can be used, and the number of holes is preferably 3000 to 12000 from the viewpoint of productivity and easy acquisition of uniform fibers. .. Further, as the nozzle, a normal circular nozzle having a diameter of 0.05 to 0.12 mm may be used, but if necessary, a nozzle having a modified cross section may be used.

As the spinning bath, for example, it is preferable to use a Mueller bath containing 95 to 125 g / L of sulfuric acid and 10 to 17 g / L of zinc sulfate. A more preferable sulfuric acid concentration is 100 to 120 g / L. When the sulfuric acid concentration is 95 g / L or more, the productivity is improved without delaying the regeneration, and when the sulfuric acid concentration is 125 g / L or less, the spinnability is improved without speeding up the regeneration. When the zinc sulfate concentration is 10 g / L or more, the regeneration on the surface of viscose does not become faster. When the zinc sulfate concentration is 17 g / L or less, the coagulation and regeneration of viscose can proceed appropriately.

The spinning speed is preferably in the range of 30 to 80 m / min. The draw ratio is preferably 39 to 55%. Here, the stretching ratio indicates how much the sliver speed after stretching is increased when the sliver speed before stretching is 100. In terms of magnification, it is 1 before stretching and 1.39 to 1.55 times after stretching.

The rayon fiber obtained as described above is cut to a predetermined length and subjected to a scouring process. The scouring step may be carried out in the order of hot water treatment, hydrosulfurization treatment, bleaching, and pickling by a usual method. After that, if necessary, excess water is removed by a method such as a compression roller or vacuum suction.

The fiber structure of the present invention includes clothing, molded bodies, reinforcing fibers, medical textiles, sanitary napkins, diapers and the like. Specifically, it can be applied to innerwear utilizing moisture absorption and heat generation, ordinary innerwear, general clothing, women's clothing, bedding fabric, interior fabric, vehicle fabric, interlining, medical hygiene material and the like. Medical textiles include masks, gauze, absorbent cloths, surgical threads and the like. There are various material forms such as cotton, thread, woven fabric, knitting, non-woven fabric, and braid.

The biodegradable regenerated cellulose fiber of the present invention has higher biodegradability than ordinary cotton, rayon and polyester. Further, the biodegradable regenerated cellulose fiber of the present invention has excellent functionality such as adsorption of harmful substances such as formarin, deodorizing performance, and ultraviolet shielding property in addition to the original moisture absorption and touch of the regenerated cellulose fiber, and further, cellulose. It is dyed extremely well not only with dyes for wool but also with acid dyes, metal-containing dyes, and chromium dyes, which are dyes for wool. Since the above-mentioned properties of the biodegradable regenerated cellulose fiber of the present invention are introduced at the stage of the undiluted spinning solution, they are also suitable for mass production.

Hereinafter, the present invention will be specifically described with reference to Examples. The present invention is not limited to the following examples.

(Example 1)
As the non-crosslinked protein, gelatin: manufactured by Nippi, trade name G-KP (number average molecular weight about 20000, freezing point 22 ° C.) was used.
Polyethylene glycol: A 40% aqueous solution was prepared by heating and melting PEG # 1540 (number average molecular weight of about 1500) manufactured by NOF CORPORATION at 60 ° C. and then dissolving it in warm water at 50 ° C.
The above-mentioned aqueous solutions of gelatin and polyethylene glycol were added to warm water at 30 ° C. and stirred so that the concentrations of the active components were 13% by mass and 9% by mass, respectively, to prepare a gelatin / polyethylene glycol aqueous solution. The pH of the obtained gelatin / polyethylene glycol aqueous solution (mixture) was 5.8.
Next, the active components of gelatin and polyethylene glycol were added to the viscose spinning solution (cellulose content 8.5% by mass, sodium hydroxide 5.7% by mass, carbon disulfide 2.7% by mass) prepared by a conventional method. A gelatin / polyethylene glycol aqueous solution was added in an amount of 10% by mass and 6.9% by mass with respect to cellulose, respectively, using an in-line mixer (TK pipeline homomixer: manufactured by Tokushu Kagaku Kogyo Co., Ltd.). It was mixed just before spinning.
The obtained spinning liquid was subjected to a two-bath tension spinning method under the conditions of a spinning speed of 50 m / min and a draw ratio of 50% in a Mueller bath (sulfate 100 g / L, zinc sulfate 15 g / L, sodium sulfate 350 g / L, spinning temperature 50). A rayon staple fiber (short fiber) having a fineness of 1.4 dtex and a fiber length of 38 mm was produced by spinning at (° C.), cutting the sliver, and scouring and drying by a conventional method.

FIG. 1 shows an optical micrograph of the side surface of the obtained biodegradable rayon fiber after differential staining. The biodegradability data of the obtained biodegradable rayon fibers are summarized in Tables 4 to 5 and FIGS. 2 to 3 below. Table 1 shows the physical characteristics of the biodegradable rayon fiber and the ordinary rayon fiber (Comparative Example 1).

[Dispersity]
The biodegradable rayon fiber obtained in Example 1 was stained with a non-crosslinked protein by differential staining. The conditions for differential staining are as follows.
(1) The product name "Kayastain Q" manufactured by Nippon Kayaku Co., Ltd. was used as the differential dye.
(2) 200 mL of a 1% aqueous solution of the differential dye (dyeing solution) and 2 g of raw cotton were put into a glass beaker, and heated at 90 ° C. for 5 minutes with an electric heater. The raw cotton was taken out from the dyeing solution, washed with 500 mL of water three times, squeezed out excess water, and then dried at 50 ° C. for 1 hour.
(3) The side surface of the differentially dyed fiber was optically observed with transmitted light using a microscope (KEYENCE; VHX-500F, lens; VH-Z500) at a lens magnification of 2000 times. It is presumed that the biodegradable rayon fiber of Example 1 is uniformly dispersed because no non-uniform state such as color unevenness was observed and the interface between cellulose and protein was not clear.

(Comparative Example 1)
Commercially available ordinary rayon fiber (viscose rayon fiber) having a fineness of 1.4 dtex and a fiber length of 38 mm was used.

(Comparative Example 2)
A commercially available polyester fiber (polyethylene terephthalate fiber) having a fineness of 1.4 dtex and a fiber length of 38 mm was used.

(Comparative Example 3)
Commercially available Chinese cotton fiber with a fineness of 3.7 micronea and a fiber length of 35 mm was used.

<Biodegradability measurement method>
(1) Replacement of measurement sample with chemical formula-Since the molecular skeleton of the biodegradable rayon fiber of Example 1, the ordinary rayon fiber of Comparative Example 1, and the cotton fiber of Comparative Example 3 is cellulose, (C ₆ H ₁₀ ). O ₅ ) It can be regarded as _n (n is a repeating unit).
-Comparative Example 2: Polyester fiber can be regarded as (C ₁₀ H ₈ O ₄ ) _n (n is a repeating unit).
(2) Measuring device and measuring conditions The measurement was performed under the following conditions in accordance with JIS K6950. The measurement was requested to the Osaka Research Institute of Industrial Science and Technology.
Device: Closed oxygen consumption measuring device (coolometer OM3100A: manufactured by Okura Electric Co., Ltd.)
Planting source: Return sludge standard test culture solution at sewage treatment plant in Osaka City: 300 mL
Planting concentration: 30 mg / L
Test temperature: 25 ± 1 ° C
Test period: 28 days The test plots are as shown in Table 2.

(3) Measurement results
(i) Theoretical Oxygen Demand (ThOD)
The theoretical oxygen demand (ThOD) of a substance whose elemental composition is represented by C _c H _h O _o was calculated by the following formula.
ThOD = 16 (2c + 0.5h-o) / Mw
However, Mw: molecular weight The ThOD of each test substance is as shown in Table 3.

(ii) Biochemical Oxygen Demand (BOD)
Biochemical oxygen demand (BOD) was calculated by the following formula.
ΔBOD = B _s −B _b
However, B _s : BOD (mg / L) of the decomposition group, B _b : BOD (mg / L) of the basal respiratory group.
The ΔBOD every 7 days after the start of the test is shown in Table 4, and the graph of the change with time is shown in FIG.

(iii) Decomposition degree Decomposition degree (D) was calculated by the following formula.
D = 100 × ΔBOD / (ThOD × M _s / 0.3)
However, M _s : the amount of the test substance added (mg)
The degree of decomposition every 7 days after the start of the test is shown in Table 5, and the graph of the change over time is shown in FIG.

As described above, it was confirmed that the biodegradable rayon fiber of Example 1 has high biodegradability. In addition, a sensory test revealed that it was flexible and had a good texture.

The fiber structure using the biodegradable regenerated cellulose fiber of the present invention is suitable for clothing, molded bodies, reinforcing fibers, medical fiber products, sanitary products, diapers and the like. Specifically, it is suitable for innerwear utilizing moisture absorption and heat generation, ordinary innerwear, general clothing, women's clothing, bedding fabric, interior fabric, vehicle fabric, interlining, medical hygiene material and the like.

Claims (18)

A biodegradable regenerated cellulose fiber containing cellulose,
Contains cellulose and non-crosslinked proteins
A biodegradable regenerated cellulose fiber characterized in that the cellulose and the non-crosslinked protein are uniformly dispersed. The biodegradable regenerated cellulose fiber according to claim 1, wherein the blending ratio of the cellulose and the non-crosslinked protein is 5 to 50 parts by mass of the non-crosslinked protein with respect to 100 parts by mass of the cellulose. The biodegradable regenerated cellulose fiber according to claim 1 or 2, wherein the biodegradable regenerated cellulose fiber further contains polyethylene glycol. The biodegradable regenerated cellulose fiber according to claim 3, wherein the polyethylene glycol is blended in an amount of 1 to 10 parts by mass with respect to 100 parts by mass of cellulose. The biodegradable rayon fiber according to any one of claims 1 to 4, wherein the biodegradable regenerated cellulose fiber is a viscose rayon fiber. The biodegradable regenerated cellulose fiber according to any one of claims 1 to 5, wherein the protein is a water-soluble protein. The biodegradable regenerated cellulose fiber according to any one of claims 1 to 6, wherein the protein is an alkali-soluble protein showing solubility in the range of pH 8 to 12. The biodegradable regenerated cellulose fiber according to any one of claims 1 to 7, wherein the protein is gelatin having a number average molecular weight of 9000 or more and less than 50,000. The biodegradable regenerated cellulose fiber according to any one of claims 3 to 8, wherein the polyethylene glycol has a number average molecular weight of 200 to 7500. The method for producing a biodegradable regenerated cellulose fiber according to any one of claims 1 to 9.
When the undiluted solution containing cellulose and the component containing the non-crosslinked protein solution are mixed to prepare a spinning solution, at least the undiluted solution containing cellulose and the non-crosslinked protein solution are mixed immediately before the spinning nozzle and then spun. A method for producing biodegradable regenerated cellulose fiber. The method for producing a biodegradable regenerated cellulose fiber according to claim 10, wherein the non-crosslinked protein solution has a pH in the range of 4 to 9. The method for producing a biodegradable regenerated cellulose fiber according to claim 10 or 11, wherein the non-crosslinked protein solution is dissolved in a solvent without adding a strong alkaline solution having a pH of 11 or higher. The method for producing a biodegradable regenerated cellulose fiber according to any one of claims 10 to 12, wherein the method of mixing immediately before the spinning nozzle is mixing by an in-line mixing means. The method for producing a biodegradable regenerated cellulose fiber according to any one of claims 10 to 13, wherein the spinning solution contains a mixed solution in which a solution of a component containing a non-crosslinked protein and polyethylene glycol is mixed. The method for producing a biodegradable regenerated cellulose fiber according to any one of claims 10 to 14, wherein the mixed solution has a pH in the range of 4 to 9. The method for producing a biodegradable regenerated cellulose fiber according to any one of claims 10 to 15, wherein the mixed solution is dissolved in a solvent without adding a strong alkaline solution having a pH of 11 or higher. A fiber structure containing the biodegradable regenerated cellulose fiber according to any one of claims 1 to 9. The fiber structure according to claim 17, wherein the fiber structure is clothing, a molded body, a reinforcing fiber, a medical fiber product, a sanitary product, or a diaper.

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