JPH08260250A - Modified starch fiber and its production - Google Patents

Abstract

PURPOSE: To obtain the subject fiber sufficient in resistance against hot water, having a practical strength, and excellent in hygroscopicity by dry-spinning a raw solution containing starch and an amino resin precondensate and subsequently thermally treating the obtained fiber. CONSTITUTION: Starch and an amino resin precondensate (preferably the precondensate of melamine with formaldehyde) are dissolved in water, etc., and the obtained spinning raw solution is dry-spun. The obtained fiber is thermally treated to convert the fiber into a modified starch fiber comprising the reaction product of the amino resin precondensate with the starch. The temperature for the thermal treatment is preferably >=100 deg.C, and the thermal drawing of the fiber on the thermal treatment improves the physical properties of the fiber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a modified starch fiber and a method for producing the same. In particular, the present invention relates to a modified starch fiber useful as a fiber for clothing and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, attempts have been made to utilize starch, which is abundant in nature, as fiber. For example, Japanese Patent Application Laid-Open No. 52-118034 describes that starch is fibrillated in an ammonium coagulation salt aqueous solution to obtain a water-insoluble fiber. In addition, JP-A-5-23971
No. 9 discloses that a softening agent or the like is added to hydroxypropyl starch and the mixture is melt-spun with polyester or the like. However, these fibers do not have sufficient resistance to hot water of 70 ° C. or higher, have low strength, and are not practical fibers.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above problems by modifying starch and provides a modified starch fiber having excellent hygroscopicity and a novel texture and a method for producing the same. is there.

[0004]

In order to solve the above problems, the modified starch fiber of the present invention has the following constitution. That is, it is a modified starch fiber characterized by comprising a reaction product of starch and an amino resin initial condensation product.

In order to solve the above problems, the method for producing modified starch fiber of the present invention has the following constitution. That is, it is a method for producing a modified starch fiber, which comprises performing dry spinning using a stock solution obtained by mixing starch and an amino resin initial condensate, and then performing heat treatment.

The present invention will be described in detail below.

The modified starch fiber of the present invention comprises a reaction product of starch and an amino resin precondensate, particularly a cross-linking reaction product.

The starch used in the present invention is a component contained in plants such as corn, wheat, rice, potato, sweet potato and tapioca, and corn starch made of corn is particularly preferable. Chemically, it is a natural polymer having glucose as a constituent unit, and is usually a mixture of amylose and amylopectin. The mixing ratio of amylose and amylopectin is arbitrary, and may be amylose alone or amylopectin alone.

The amino resin initial condensate used in the present invention is specifically an initial condensate of an amino compound such as urea, thiourea, guanidine, dicyandiamide, melamine, acetoguanamine and benzoguanamine with formaldehyde. Of these, an initial condensate of melamine and formaldehyde is preferable from the viewpoints of cross-linking reactivity with starch and wide industrial availability.

Regarding the mixing ratio of starch and amino resin initial condensate, it is particularly preferable to mix both such that the amino resin initial condensate is contained in the crosslinking reaction product in an amount of 2% by weight or more and 50% by weight or less. If the content of the amino resin initial condensate in the cross-linking reaction product is less than 2% by weight, the strength and hot water resistance of the resulting modified starch fiber may decrease. If the content exceeds 50% by weight, moisture absorption will occur. In some cases, the properties of the modified starch fiber may be reduced and the effect of the modified starch fiber may be reduced.

The modified starch fiber of the present invention can be manufactured as follows.

First, the above-mentioned starch and amino resin initial condensate are mixed in a medium. Any medium can be used as a medium for mixing as long as it dissolves starch and the amino resin initial condensate, but water or dimethyl sulfoxide (hereinafter referred to as DMSO) is preferably used in terms of good solubility.

After starch is dissolved in the above medium with stirring, an amino resin compound is added and mixed to prepare a spinning dope. If crosslinking proceeds before spinning, spinning becomes difficult. Therefore, it is preferable to mix at a mixing temperature of 100 ° C. or less and a mixing time of 12 hours or less.

As a mixing device, a mixing device with a stirring blade, a static mixing device, a pipe mixing device, a roll, a Banbury mixer, a pressure kneader, a screw type kneading extruder,
A known one such as a rotor type kneader can be used.

During the mixing, a small amount of a catalyst for promoting crosslinking during heat treatment may be added.

Using the spinning dope thus obtained, dry spinning is carried out, and heat treatment is carried out to promote cross-linking to obtain a modified starch fiber.

As a dry spinning method, a known dry spinning method can be applied, and generally, a spinning dope is extruded from a spinneret hole and the medium is evaporated with hot air.

As a heat treatment method, a known heat treatment method can be applied, and the heat treatment temperature is preferably set to 100 ° C. or higher in order to effectively proceed the crosslinking.

Further, performing heat drawing simultaneously with heat treatment is effective for improving the physical properties of the obtained fiber.

The modified starch fiber thus obtained is not only excellent in hygroscopicity, has a new texture, and has good hot water resistance, but also has a strength of 0.5 g / d or more, preferably 0.8 g. / D or more, more preferably 1.0 g / d
The above has practical fiber performance.

Further, the fiber of the present invention is characterized in that it does not melt even in hot water of 70 ° C. or higher and has good heat resistance. Amino resin initial condensate, by reacting with starch, the mechanism for improving the hot water resistance and further strength of starch is not necessarily clear, but the amino resin initial condensate reacts with the hydroxyl group of the starch molecule, It is considered that the hydrophilicity of the hydroxyl group is weakened and the skeleton of starch itself is strengthened by the crosslinked structure.

It is optional to add other polymers, colorants, pigments and other known additives to the modified starch fiber obtained in the present invention depending on the purpose.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples. In the present invention, the strength and moisture absorption rate are JIS L
Tensile strength (g / d) measured from 1013 and temperature 2
Equilibrium moisture content (%) at 0 ± 2 ° C. and 65 ± 2% relative humidity.

Example 1 200 g of corn starch was dissolved in 800 g of water with stirring at 120 ° C. under pressure to prepare a 20 wt% aqueous solution. To 1000 g of this solution, 20 g of an 80% aqueous solution of an initial condensate of melamine and formaldehyde (“Sumitex Resin M-3” manufactured by Sumitomo Chemical Co., Ltd.) was added and mixed at 40 ° C. Dry spinning was performed using the mixed aqueous solution of the starch and the amino resin initial condensate to obtain 200
Heat treatment was performed at ℃. The modified starch fiber obtained did not melt even after being treated in boiling water for 30 minutes.
The strength of the obtained fiber is 1.6 g / d and the moisture absorption rate is 1.
It was 3%, and had a novel texture not found in conventional clothing fibers.

(Example 2) 200 g of corn starch was added to D
The mixture was dissolved in 800 g of MSO at 60 ° C. with stirring to prepare a 20 wt% aqueous solution. To 1000 g of this solution, 40 g of an 80% aqueous solution of an initial condensate of melamine and formaldehyde (“Sumitex Resin M-3” manufactured by Sumitomo Chemical Co., Ltd.) was added 4 times.
The mixture was added and mixed at 0 ° C. Dry spinning was carried out at 200 ° C using a mixed aqueous solution of this starch and the amino resin initial condensation product.
Heat treatment was performed. The modified starch fiber obtained did not melt even after being treated in boiling water for 30 minutes. The strength of the obtained fiber is 1.7 g / d, and the moisture absorption rate is 12.
%, And had a novel texture not found in conventional clothing fibers.

(Comparative Example 1) Using a 10% by weight aqueous solution of starch, fibers were obtained by wet spinning and drawing in an aqueous ammonium salt solution. The moisture absorption rate of the obtained fiber was as high as 14%, but the strength was as low as 0.3 g / d, and the fiber was melt-fused in boiling water.

(Comparative Example 2) 10 wt% DMS of starch
Fibers were obtained by wet spinning and drawing in methyl alcohol using O solution. Moisture absorption of the obtained fiber is 14%
However, the strength was as low as 0.2 g / d, and the material melted in boiling water.

(Examples 3 to 5) Modified starch fibers were obtained in the same manner as in Example 1 except that the kind of the amino resin initial condensate was changed as shown in Table 1. The results are shown in Table 1. All the fibers had good strength and moisture absorption rate, and did not melt even when treated in boiling water. In addition, it had a novel texture not found in conventional clothing fibers.

[0029]

[Table 1] (Examples 6 to 10) Example 1 except that the content of the amino resin initial condensate in the crosslinking reaction product was changed as shown in Table 1.
A modified starch fiber was obtained in the same manner as in. Table 2 shows the results. All the fibers had good strength and moisture absorption rate, and did not melt even when treated in boiling water. In addition, it had a novel texture not found in conventional clothing fibers.

[0030]

[Table 2]

[0031]

EFFECTS OF THE INVENTION Modified starch fibers having good hot water resistance, excellent hygroscopicity and practical fiber performance can be provided.

Claims (3)

[Claims] 1. A modified starch fiber comprising a reaction product of starch and an amino resin initial condensate. 2. The modified starch fiber according to claim 1, wherein the content of the amino resin initial condensate in the reaction product is 2% by weight or more and 50% by weight or less. 3. A method for producing a modified starch fiber, which comprises subjecting a stock solution obtained by mixing starch and an amino resin initial condensate to dry spinning followed by heat treatment.