JPH0711088B2 - Binder fiber and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a binder fiber and a method for producing the same, more specifically, it plays a role of binding between fibers in a dry state, but when it is put into water, it hydrogels to form a binding force. The present invention relates to a binder fiber that loses its properties and a manufacturing method thereof.

“Conventional technology and problems” In recent years, due to the increased demand for sanitary products and diapers, when they are put into the water after use, they can be quickly disaggregated into the constituent fibers and the like, and can be disposed of in the flush toilet. The emergence of new paper products is required. It is expected that this demand will become particularly strong in the field of diaper for incontinence as the average life expectancy increases and the society ages more and more in the future.

Conventionally, since it has very little or does not have self-adhesiveness, even if it has a very small, when making a pulp-like material or short fibers that cannot be paper-formed alone, as a binder fiber to be used as a mixture, So far, polyvinyl alcohol fibers, ethylene-vinyl acetate copolymer fibers, polyethylene fibers, polypropylene fibers or composite fibers thereof have been known. These binder fibers are mixed with short fibers serving as a required main material to form a paper-like body and then heated to bond these short fibers to each other.

However, among the conventional binder fibers, those made of ethylene-vinyl acetate copolymer, polyethylene, and polypropylene are stable against water, and it is very difficult to disintegrate them into a fibrous shape with a water stream. Polyvinyl alcohol fiber also swells in water at room temperature but does not dissolve, so disaggregate it without heating, adding chemicals, or applying special shearing force to a pulper, etc. I can't.

Therefore, until now, there has been no known binder fiber which gives a paper-like product which can be easily disintegrated into individual fibers with a shearing force equivalent to the flush flow of a flush toilet.

"Means for Solving Problems" The present invention has an interfiber binding force in a dry state and exhibits a strengthening effect on a paper-like material, but absorbs water in a wet state to become a hydrogel and loses an interfiber binding force, The purpose of the present invention is to provide a binder fiber that can be easily disintegrated even with a small shearing force.

That is, the first aspect of the present invention is a mixture of alginate and a derivative of alginic acid (excluding alginic acid alkylene glycol ester), which is a binder fiber composed of a non-aqueous hydrogel, and the second aspect of the present invention is water-soluble. A method for producing a binder fiber is characterized in that an aqueous dope containing a derivative of alginate and alginic acid (excluding alkylene glycol ester of alginic acid) is wet-spun to form a fiber composed of a water-insoluble hydrogel. To do.

The binder fiber of the present invention can be obtained by wet spinning an aqueous dope containing a water-soluble alginate and an alginic acid derivative to form a fiber composed of a water-insoluble salt.

As the derivative of alginic acid used in the present invention, a product obtained by converting alginic acid into the following compound is suitable.

(A) When blocking a carboxyl group (1) Methyl ester methyl ester, methoxymethyl ester, methylthiomethyl ester, tetrahydropyranyl ester, tetrahydrofuranyl ester, 2-methoxyethoxymethyl ester, benzyloxymethyl ester, phenacyl ester, Ethyl ester and the like.

(2) 2-Substituted ethyl esters 2,2,2-trichloroethyl ester, 2-chloroethyl ester, 2-methylthioethyl ester, 2- (p-
Toluenesulfonyl) ethyl ester, t-butyl ester, cyclohexyl ester, allyl ester, phenyl ester, benzyl ester and the like.

(3) Silyl esters Trimethylsilyl ester, t-butyldimethylsilyl ester and the like.

(4) Thioesters S-t-butyl ester, S-phenyl ester and the like.

(5) Other esters 2,4-dinitrophenylsulfenyl ester, 1,3-oxazoline and the like.

(6) Amide N, N-dimethylamide, pyrozinamide, piperidineamide and the like.

(7) Hydrazide N-phenylhydrazine, N, N'-diisopropylhydrazine and the like.

(B) Blocking hydroxyl groups (1) Ethers methyl ether, t-butyl ether, 2-methoxyethoxymethyl ether, allyl ether, methylthiomethyl ether, benzyl ether, triarylmethyl ether, trimethylsilyl ether, dimethyl-t-
Butyl silyl ether etc.

(2) Acetals, ketals Tetrahydropyranyl ether, tetrahydrothiofuranyl ether, tetrahydrothiopyranyl ether, methoxytetrahydropyranyl ether and the like.

(3) Carboxylic acid ester acetate, benziate, p-nitrobenzoate,
Formate, trifluoroacetate, chloroacetate, methoxyacetate, phenoxyacetate, ethoxycarbonyl, methoxycarbonyl, t-butylcarbonyl, 2,2,2-trichloroethoxycarbonyl, 2,2,2
-Trichloroethyl formate, trimethyl acetate and the like.

(4) Non-carboxylic acid ester nitrate, tosylate, 2,4-dinitrobenzenesulfate, etc.

For diols, methyl acetal, ethylidene acetal, benzylidene acetal, isopropylidene ketal, cyclohexylidene ketal, orthoformate, etc.

The extent to which the carboxyl group or the hydroxyl group is compounded is such that the alginic acid derivative is soluble in water. The alginic acid derivative used in the present invention includes a blocked product of a carboxyl group of alginic acid and a blocked product of a hydroxyl group of alginic acid, respectively, or a mixture thereof.

Examples of the water-soluble alginate used in the present invention include sodium alginate, potassium, and ammonium salts,
Magnesium salts and mercury salts are included, and these may be used alone or in combination of two or more.

The mixing role of the water-soluble alginate and the alginic acid derivative is selected within the range of 95: 5 to 10:90 by weight. In this case, the higher the proportion of the alginic acid derivative, the more easily the obtained fiber becomes a hydrogel. However, if it is too high, the coagulation rate at the time of spinning is lowered, and the work efficiency is lowered. Therefore, the above range is preferable. .

The spinning dope is prepared by dissolving the above-mentioned mixture of the water-soluble alginate and the alginic acid derivative in water at a concentration in the range of 2 to 10% by weight. At this time, the water-soluble alginate and the alginic acid derivative may be separately weighed in predetermined amounts and added to water, or the alginic acid derivative having a low reactivity may be formed at the time of production to obtain a desired ratio. A block polymer substance containing the corresponding alginate and derivative may be added to water.

The dope thus obtained is defoamed and provided for spinning. The spinning is performed by quantitatively extruding the above-mentioned dope quantitatively by a gear pump or the like from a spinneret equipped with a large number of nozzles during solidification and melting.

As the coagulation solution, a solution containing a water-soluble salt of a metal ion that can be exchanged with the cation of a water-soluble alginate to make it insoluble is used. Examples of such water-soluble salts include hydrochlorides, sulfates, nitrates and phosphates of metals such as calcium, barium, strontium, aluminum, zinc, nickel, cobalt, chromium, copper, manganese and lead. it can. These water-soluble salts may be used alone or in combination of two or more.

In this coagulation dissolution, in order to modify the fiber surface as necessary, a hydrophilic organic solvent such as methanol, ethanol, acetone, ethyl acetate, ethyl formate, acetic acid amide,
Formic acid amide and various surfactants can be added.

The spinning of the binder fiber of the present invention is carried out by a wet method by discharging the above water-based dope into a coagulating liquid through a nozzle. Considering the effect as a binder, it is preferable to reduce the nozzle diameter to spin into a fiber having a small fineness because the specific surface area becomes large, but if the fineness is too small, the fiber strength becomes insufficient. .
A range of 01 to 0.5 mm is suitable.

The spun fiber is wound on a take-up roller and cut into a length suitable for papermaking, that is, 1.0 to 20.0 mm, preferably 2.0 to 10.0 mm.

"Operation / Effect" The binder fiber thus obtained retains a hydrogel-like fiber form in the presence of water, and can be easily mixed with other short fibers or a pulp-like substance to be easily made into paper.
When it is dried, it exhibits an action of adhering each fiber to each other, but when it is put into water again, it reversibly hydrogels and loses its adhering action, so that the fibers are disintegrated.

The binder fiber of the present invention can be mixed with another fiber material which does not have self-adhesiveness and used for forming a sheet. The fibrous material is not particularly limited, but examples thereof include flack pulp, rayon fiber, cupra fiber, chitin fiber, collagen fiber, acrylic fiber, polyolefin fiber, polyamide fiber, polyester fiber and the like. Since these do not have self-adhesiveness, they cannot be made into sheets by papermaking alone, but if binder fibers are mixed at a ratio of 10 to 100% by weight to these, papermaking should be performed according to a conventional method. Can easily manufacture a sheet. The sheet-shaped molded product produced using the binder fiber of the present invention has high strength in a dry state, but in water, the binder fiber rapidly absorbs water to become a hydrogel, and at the same time, the sheet loses its adhesive ability, so that the sheet is It becomes easy to disintegrate into each constituent fiber,
It can be disintegrated even with the shearing force of the flush flow of flush toilets. Furthermore, the binder fiber of the present invention has the property of rapidly undergoing ion exchange with alkali metal ions in an alkaline aqueous solution and dissolving in water.

"Examples" Hereinafter, the present invention will be described in more detail with reference to Examples and Reference Examples, but the present invention is not limited thereto.

Example 1 A mixture of 30 parts by weight of sodium alginate and 70 parts by weight of acetylated sodium alginate was added to ion-exchanged water and stirred to obtain a 4% by weight aqueous solution. This was left overnight to obtain a uniform solution, which was used as a spinning dope. The dope was poured into a glass branch flask and left for about 2 hours for defoaming. Using the flask as a dope feeder, the back pressure was 1.0 kg / cm ² , the dope was discharged at 24.8 ml / min by a gear pump, and the nozzle (0.1 mmφ × 1,
500H) and extruded into a first coagulation solution consisting of a 5% aqueous solution of calcium chloride to obtain a gel-like water-insoluble fiber. The fiber was passed through a first clover roll, into a second washing bath, through a second clover roll, into a third washing bath, and wound on a cassette. At this time, the spinning speed was 2.1 m / min, the peripheral speed of the first roll was 7.6 m / min, and the peripheral speed of the second roll was 9.5 m / min. Therefore, the draft ratio for one bath was 3.62, and the extension ratio in the bath was 1.25.
The fineness of the obtained fiber was 0.63 denier.

The continuous yarn wound up was a konjak-like extremely soft and low-strength fiber. This was removed from the cassette, air-dried under a slight load, semi-dried, and then cut to a fiber length of 3.0 m / m with a guillotine cutter to obtain a binder fiber.

This binder fiber swells quickly when dispersed in water.
Dispersed and became homogeneous as if it had dissolved. However, the aqueous dispersion had no tackiness at all, and the binder fiber was dispersed as a fibrous hydrogel.

Example 2 Binder fibers were produced in the same manner as in Example 1 except that a mixture of sodium alginate and sulfuric acid alginate in a weight ratio of 3: 7 was used as a raw material.

Example 3 A binder fiber was produced in the same manner as in Example 1 except that a mixture of sodium alginate and methyl alginate in a weight ratio of 7: 3 was used as a raw material.

Reference Example 1 3 denier polypropylene short fibers for papermaking with a fiber length of 5 mm 1
20 parts by weight of the binder fiber obtained in Example 1 was added to 00 parts by weight to produce polypropylene paper according to JIS P8209. The water dispersibility of the short fibers for papermaking was extremely good, and a polypropylene paper with a good texture was obtained. The physical properties of the polypropylene paper are shown in Table 1.

When this polypropylene paper was immersed in water and left for a while, the bond between the constituent fibers disappeared, and the polypropylene fiber was easily disintegrated by stirring with a glass rod, and eventually a completely uniform fiber dispersion state without binding fiber was obtained.

Reference Example 2 Polyester short fiber for papermaking of 1.5 denier with a fiber length of 5 mm 10
15 parts by weight of the binder fiber obtained in Example 2 was added to 0 part by weight, and the same papermaking as in Reference Example 1 was performed. The physical properties of the obtained polyester paper are shown in Table 1.

Reference Example 3 The same papermaking as in Reference Example 1 was carried out by adding 10 parts by weight of the binder fiber obtained in Example 3 to 100 parts by weight of rayon for papermaking having a fiber length of 5 mm and a thickness of 1.5 denier. The physical properties of the obtained rayon paper are shown in Table 1.

 ─────────────────────────────────────────────────── --Continued from the front page Examiner Takuko Funakoshi (56) References JP-A-56-169809 (JP, A) JP-A-61-174499 (JP, A) JP-A-62-141121 (JP, A)

Claims (7)

[Claims] 1. A derivative of alginate and alginic acid (excluding alginic acid alkylene glycol ester).
And a binder fiber comprising a water-insoluble hydrogel. 2. The binder fiber according to claim 1, wherein the derivative of alginic acid is a product obtained by blocking the carboxyl group of alginic acid with at least one selected from esterification, amidation and hydrazidation. . 3. The product of claim 1, wherein the alginic acid derivative is a product obtained by blocking the hydroxyl group of alginic acid with at least one selected from etherification, esterification, acetalization and ketalization. Binder fiber. 4. A binder fiber, characterized in that a water-based dope containing a water-soluble alginate and a derivative of alginic acid (excluding alginic acid alkylene glycol ester) is wet-spun to form a fiber composed of a water-insoluble hydrogel. Manufacturing method. 5. The production method according to claim 4, wherein the mixing ratio of the water-soluble alginate and the derivative of alginic acid is in the range of 95: 5 to 10:90 by weight. 6. The product of claim 4, wherein the alginic acid derivative is a product obtained by blocking the carboxyl group of alginic acid with at least one selected from esterification, amidation, and hydrazidation. The manufacturing method described. 7. The product of claim 4, wherein the alginic acid derivative is a product obtained by blocking the hydroxyl group of alginic acid with at least one selected from etherification, esterification, acetalization and ketalization. The manufacturing method according to item 5.