JPH08199420A - Production of highly flexible vegetable fiber - Google Patents

Abstract

PURPOSE: To obtain highly flexible continuous fibers useful even for high-grade fabrics, etc., by treating a stock such as fiber bundles extracted from a vegetable raw material in an aqueous solution containing an alkaline substance and hydrogen peroxide under mild conditions. CONSTITUTION: A vegetable stock including fiber bundles or fiber bundles extracted from such stock are treated in an aqueous solution containing an alkaline substance and hydrogen peroxide (generator) under mild conditions (at normal temperatures to 50 deg.C for 2-48h, or at 50 deg.C to the boiling point of the solution for 0.5-24h) The concentrations of the alkaline substance in terms of Na2 O and hydrogen peroxide in terms of H2 O2 in the solution are 0.1-4wt.% and 0.02-3wt.%, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a long flexible plant fiber from a plant-based raw material containing a fiber bundle or a fiber bundle collected from the raw material.

[0002]

2. Description of the Related Art Plant leaves, stems, skins and the like have a length of 3
Single fibers of about 6 mm are included as a long fiber bundle that is hardened with pectin and lignin. These fiber bundles are collected from plants and used as raw fibers for obtaining fiber products such as ropes, bags, and woven fabrics. A fiber bundle mechanically collected from a plant (hereinafter, also referred to as a fiber) is coarse and rigid, and therefore can be used only for products such as ropes, canvas and bags, and cannot be used as textile fibers.

[0003] Conventionally, as a method for obtaining fine fibers that can be used for a woven fabric or the like from such a coarse and rigid fiber bundle, a method of fermenting the fiber bundle for several weeks is known. This method is a method of fermenting and removing pectin and lignin in a fiber bundle to obtain fine fibers. However, in this method, pectin removal can be performed relatively easily, but lignin removal is difficult, and the lignin removal rate is limited,
Only about 3 to 7% of the lignin content contained in the fiber bundle is removed. Therefore, cellulose and lignin are concentrated in the fiber thus obtained, and the lignin content is increased, so that the flexibility and the bleaching property thereof are not yet satisfactory. Further, since this method is a fermentation process, it can be applied only to those with a relatively small amount of lignin that is relatively easily biodegraded, and fiber bundles that have advanced wood conversion, for example, for fiber bundles contained in pineapple and banana trunks, etc. However, it is impossible to obtain a practical fiber. Also,
Since the above method is a fermentation process, it takes a long time to produce the fiber, so that there is also a problem that the cellulose is decomposed and the strength is lowered.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for efficiently producing long flexible fibers from a plant-based raw material containing a fiber bundle or a fiber bundle collected from the raw material. And

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, a plant-based raw material containing a fiber bundle or a fiber bundle collected from the raw material is used as a raw material,
There is provided a method for producing plant fibers, characterized by gently treating this in an aqueous solution containing an alkaline substance and hydrogen peroxide or a hydrogen peroxide generator to obtain long fibers having a high flexibility.

The raw material used in the present invention is a plant containing fiber bundles or fiber bundles collected therefrom. Specifically, banana, abaca (manila hemp), pineapple, sisal, orchid orchid leaves, petioles, stems or fiber bundles obtained from them; jute (indian hemp), kenaf (Bombay hemp),
Kozo, Mitsumata, bast such as mulberry and goose bark, and fiber bundles obtained from the bast. Since the fiber bundle is easier to handle than plant leaves or bast, the fiber bundle is preferable as a raw material. Collection of fiber bundles from plants can be performed by a conventionally known method. In this case, it is preferable to use not only mechanical force but also biodegradation treatment using microorganisms and / or enzymes.

In the present invention, the treatment liquid for treating the fiber bundle or the plant-based raw material containing the fiber bundle is an aqueous solution containing an alkaline substance and hydrogen peroxide. As the alkaline substance, hydroxides, carbonates and bicarbonates of sodium or potassium are used. This alkaline substance exhibits a delignification action. And since hydroxide has strong alkalinity, it is suitable when manufacturing a flexible vegetable fiber from a raw material with a relatively large amount of lignin that has been relatively woody. However, in the case of producing plant fibers from ordinary raw materials, it is preferable to use a mixture of hydroxide and carbonate or a carbonate alone. When using a raw material that is lightly woody, it is preferable to use a mixture of carbonate and bicarbonate or bicarbonate alone, and flexible fibers can be obtained in good yield without damaging the fibers.
The amount of alkaline substances used is Na ₂ O
It is 2 to 10% by weight, preferably 5 to 10% by weight in terms of conversion.

Hydrogen peroxide has the effect of facilitating delignification when coexisting with an alkaline substance and improving the whiteness of the product. This effect uses a compound that generates hydrogen peroxide in the reaction system instead of hydrogen peroxide. Will be expressed. Therefore, a hydrogen peroxide generator such as a water-soluble organic peracid or a water-soluble salt thereof, a water-soluble inorganic peracid or a water-soluble salt thereof, or a water-soluble adduct of hydrogen peroxide and an inorganic compound is used instead of hydrogen peroxide. You may add. The amount of these used as H ₂ O ₂ is 1 to 30% by weight, preferably 3 to 10% by weight of the absolutely dry raw material. In addition to the above, various additives can be added to the treatment liquid as needed. For example, chelating agents, anthraquinone compounds and magnesium compounds can be added. In addition, when using raw materials with a low lignin content such as mitsumata or jute bast or crude fiber, adding oxalic acid or its water-soluble salt to the treatment liquid almost eliminates the dissolution and removal of lignin and pectin to be removed. At the same time, the fiber bundles are softened and bleached quickly and effectively. The amount of oxalic acid added here is 5 to 5 of all the alkali metals in the treatment liquid.
80%, preferably 15-50%, is the amount converted to oxalate.

The chelating agent inactivates the heavy metal ions contained in the processing liquid and the raw material. Hydrogen peroxide decomposes rapidly with heavy metal ions, but the addition of a chelating agent can prevent the decomposition of hydrogen peroxide. Further, the whiteness of the plant fiber obtained by adding the chelating agent is improved. As the chelating agent having such an effect, all known products can be used, but citric acid, EDTA (ethylenediaminetetraacetic acid), DTPA (diethylenetriaminepentaacetic acid), diphosphonic acid and the like are preferable and represented by the following general formula (1). Diphosphonic acid or its water-soluble salts are particularly preferred.

Embedded image (However, R represents an alkyl group having 1 to 11 carbon atoms)

Since diphosphonic acid and its salts are dissolved in the treatment solution and show effects, water-soluble salts such as sodium salts and potassium salts are preferable as the diphosphonate. Addition of diphosphonic acid or a salt thereof has the effect as the chelating agent, and also has the effects of reducing the amount of anthraquinone compound used and making water-insoluble magnesium compounds and the like water-soluble. Therefore, when a magnesium compound which is insoluble or hardly soluble in water is added to the treatment liquid, it is preferable that the magnesium compound is made water-soluble by a method such as heating in water containing diphosphonic acid and then added to the treatment liquid. In addition, since the chelating agent and the magnesium compound can be made water-soluble in the presence of diphosphonic acid, the chelating agent and the magnesium compound to be added to the treatment liquid in the presence of the compound can be freely selected regardless of the solubility. You can The chelating agent may be added singly or in combination of two or more kinds to the treatment liquid, and the addition amount thereof is 0.03 to 5% by weight, preferably 0.2 to 2% by weight of the absolutely dried raw material.
Is.

The anthraquinone compounds include anthraquinone, alkyl anthraquinone, dihydroxy anthracene and alkyl dihydroxy anthracene. When the above-mentioned anthraquinone compound is added to a treatment liquid containing an alkaline hydrogen peroxide aqueous solution as a main component, it acts as a redox catalyst for lignin and hemicellulose that coexist with cellulose, and a remarkable delignification effect is obtained. This effect is remarkable when one alkyl group having 1 to 12 carbon atoms, particularly 2 to 5 carbon atoms is contained in the molecule. Further, the substitution position of the alkyl group is preferably β-position. The anthraquinone compound may be used alone or as a mixture of two or more selected from the above, and the addition amount thereof is 0.01 to 2% by weight, preferably 0.03 to 0.3% by weight of the absolutely dry raw material. %.

The magnesium compound has the effect of preventing the decomposition of cellulose and can improve the quality of the fiber obtained by adding it to the treatment liquid. This effect is presumed to be due to the effect of the magnesium compound to prevent the collapse of cellulose by the alkaline hydrogen peroxide solution. Further, the magnesium compound used in the present invention is preferably water-soluble, but when it is insoluble in water, it may be treated with diphosphonic acid or a salt thereof to make it water-soluble, and is not limited to a water-soluble compound. Therefore, the magnesium compound may be added as one kind or a mixture of two or more kinds selected from oxides, carbonates, sulfates, chlorides, lactates, acetates and the like. It should be noted that the addition of a magnesium compound as an organic acid salt is preferable when recovering and reusing an alkaline substance or the like from the liquid after the treatment, since polluting elements such as chlorine and sulfur do not accumulate in the treatment liquid. The addition amount of the magnesium compound is 0.02 to 1% by weight, preferably 0.1 to 0.5% by weight as MgO with respect to the absolutely dried raw material.

In the present invention, lignin and pectin in the raw material are dissolved and removed in the treatment liquid to obtain long fibers having a high flexibility. In the case of the present invention, it is important to treat the raw material gently,
Severe treatment shortens the fiber bundle, which is not preferable. The raw material treatment temperature of the present invention is not particularly limited, but is generally not higher than the boiling point of the treatment liquid at room temperature or atmospheric pressure. The treatment time is 2 to 48 when treated at room temperature to 50 ° C.
The time is preferably 6 to 24 hours, and is 0.5 to 24 hours, preferably 2 to 8 hours when treated at 50 ° C to the boiling point of the treated water. The concentration of the alkaline substance in the treatment liquid is 0.1 to 4% by weight as Na ₂ O, preferably 0.1.
It is preferable to be 2 to 2% by weight. Further, the concentration of hydrogen peroxide is 0.02 to 3% by weight as H ₂ O ₂ , preferably 0.1.
It is preferable to set it to 1 to 0.8% by weight.

According to the present invention, not only pectin in the raw material but also lignin can be easily removed. In the case of the present invention, the lignin content is 30 to 100 of the total lignin in the raw material.
It may be treated so as to remove wt.%, Preferably 60 to 90 wt.%. In the long fiber obtained in the present invention,
The lignin content is 7% by weight or less, preferably 3% by weight or less, and the lower limit value is not particularly limited, but is usually about 0.5 to 3% by weight. If the lower limit of the lignin content is lower than this value, the strength of the fiber will be significantly impaired, which is not preferable. The pectin content is 5% by weight or less, preferably 2% by weight or less, and the lower limit thereof is not particularly limited, but is usually about 0.3 to 2% by weight. If the pectin content is lower than this range, the strength of the fiber is significantly impaired, which is not preferable.
Also, the fibers of the present invention generally have a Young's modulus of 120-350. The length of the fiber used as a raw material in the present invention is 30 cm or more, preferably 100 cm or more, and the thickness (diameter) of the fiber is usually 500 μm or less, preferably 50 to 200 μm.

In the present invention, a container for processing fiber bundles or plant-based raw materials containing fiber bundles is made of a heavy metal container in which heavy metal ions that promote the decomposition of hydrogen peroxide are eluted, or a container made of aluminum or enamel ironware which is weak against alkaline substances. It is preferable to avoid it. Therefore, it is preferable to use a stainless steel container or a container lined with stainless steel. Also. During the processing of the raw material, lignin and pectin in the raw material become water-soluble and are removed by the chemicals in the processing liquid, so that the raw material and the fresh material are vibrated and swirled while being immersed in the processing liquid. It is preferable to improve contact with the processing liquid. for that reason,
It is desirable to forcibly circulate the treatment liquid or to give high-frequency vibration from the ultrasonic generator to the treatment liquid. The frequency of high-frequency vibration is 10 ⁵ to 10 ⁷ hertz, preferably (5 to 5 Hz).
50) × 10 ⁵ Hertz is good. By such a method, the fiber bundle can be loosened and made flexible while keeping the length of the fiber bundle, but by a method such as tapping the fiber bundle from the lateral direction during or after the treatment with the treatment liquid. More preferably, the fiber bundle is repeatedly subjected to mechanical compression and relaxation from the lateral direction. And, according to this method, extremely delicate and flexible high-quality plant fibers can be obtained.

In the present invention, the raw material fiber bundle is made into a single fiber, and a single fiber or a bundle of single fibers is produced as a by-product. Although this by-product also occurs when hemp is produced by the conventional method, it is difficult to use it for pulp or the like because the conventional method has a large amount of lignin in the by-produced monofilament or binding fiber. However, since the amount of lignin in the single fiber or the binding fiber produced as a by-product in the method of the present invention is small and the whiteness is high, if they are separated from the desired flexible and long plant fibers, they can be directly used as pulp. You can The waste liquid generated in the present invention is
Energy can be recovered as heat by concentrating this to a solid content of about 50 to 70% by weight and burning, and if a water-soluble component is separated and recovered from the ash after energy recovery, an alkali metal can be recovered as a carbonate. You can Also,
When oxalic acid is contained in the treatment liquid, oxalic acid can be recovered as a calcium salt precipitate by adding a calcium salt to the treatment liquid.

[0017]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, all% described below are% by weight.

Example 1 2000 kg of leaves separated from an old strain of pineapple were used as a raw material, and this was hung on a fiber extractor consisting of two blades to collect cord fibers. This was dried in the sun to obtain 55.6 kg of crude fiber having a lignin content of 10.4%. The crude fiber was charged into a flat kettle lined with stainless steel having an internal volume of 600 liters, to which 556 liters of a treatment liquid having the following composition was added and treated at 90 ° C. for 10 hours. Amount of chemicals in treatment liquid (vs. air-dried raw material) NaOH (as Na ₂ O) 8% H ₂ O ₂ 3% Anthraquinone 0.05% EDTA 0.5% MgO 0.1% After washing the fibers after treatment When the flexible long fiber and the single fiber are separated from the above, 34.2 kg (yield 6%) of the flexible fiber having a whiteness (hunter) of 73.8% and a lignin content of 4.7%.
1.5%) and 5.7 kg of monofilament with a Kappa number of 20.1.
(Yield 10.3%) was obtained. This single fiber could be used as a high quality pulp.

Example 2 200 kg of an old trunk from which a banana fruit was collected was cut down and sandwiched between rollers to squeeze and squeeze. After the juice is removed, the stem is treated with steam at 100 ° C for 30 minutes, and then the internal volume of 300
Charge into a liter stainless steel container and add water to it.
Liter, 200 g of pectinase and 50 g of amylase were added, and the mixture was kept at 60 ° C. for 8 hours and then washed with water to obtain 11.5 kg of a crude fiber bundle having a lignin content of 12.9%. The bundle of crude fibers was placed in a stainless steel pot having an internal volume of 200 liters equipped with an ultrasonic generator of 1 megahertz, and 115 liters of a treating solution having the following composition was added thereto, and 90 ° C. while applying ultrasonic waves to the solution. Treated for 5 hours. After the treatment, a bundle of fibers washed with water and dried was placed on a plate and beaten with a mallet to obtain 5.8 kg of flexible long fibers having a brightness of GE83.2% and a lignin content of 5.3% ( 50.5% yield from crude fiber, 2.6 yield from old trunk
%), And 0.66 kg of monofilament with a Kappa number of 12.6 at the same time.
(Yield from crude fiber 5.7%) was obtained. Drug content in the treatment liquid (Taikazeinui material) KOH (Na ₂ O molar _{basis) 4% K 2 CO 3 (} Na 2 O molar _{basis) 6% H 2 O 2 7} % β- amylanthraquinone 0.1% Formula Represented by (1), R is a decyl diphosphonic acid 1.0% MgO 0.1%

Example 3 The skin of jute was peeled off, and the air-dried amount was 30 kg.
Into a stainless steel container with an internal volume of 300 liters, add 200 liters of water and 25 pectinase.
When 0 g was added and the mixture was heated and treated at 60 ° C. for 8 hours and then washed with water, a bundle of crude fibers having a lignin content of 18.2% 21.3 kg
was gotten. The crude fiber bundle was charged into a stainless steel reactor having an internal volume of 300 liters equipped with a heat exchanger and a forced circulation device for liquid, and 213 liters of a treatment liquid having the following composition was added to the reactor while forcibly circulating the liquid. It was treated at 4 ° C. for 4 hours. After the treatment, a bundle of fibers washed and dried was placed on a board and beaten with a mallet. Hemp 13 with a brightness of GE 68.1%, a lignin content of 8.7% and a pectin content of 0.3% .4 kg (yield from crude fiber 63.1%) is obtained, and single fiber with a kappa number of 28.1 is 0.83 k.
g was obtained. Amount of chemicals in treatment liquid (air-drying raw material) Na ₂ CO ₃ (as Na ₂ O) 8% NaHCO ₃ (as Na ₂ O) 10% H ₂ O ₂ 7% 9,10-dihydroxyanthracene 0.1% Represented by the general formula (1), R is an octyl-based diphosphonic acid 1.0% MgO 0.1%

Example 4 A groove having the skin removed was exposed to cold water and dried to obtain so-called white skin of 5.2 kg. The white skin of the groove was placed in a stainless steel flat pot having an internal volume of 100 liters, and 52 liters of a treatment liquid having the following composition was added thereto, and treated at 90 ° C. for 3 hours while applying ultrasonic waves of 1 MHz to the treatment liquid.
When the flexible filaments and the monofilaments are separated after washing the treated fibers with water, the flexible filaments containing 5.3% lignin and 4.1% pectin and having a brightness of GE89.6% 65.
In addition to obtaining kg (yield 70.1% based on the peel), 0.39 kg (yield 7.5%) of single fiber having a kappa number of 8.2 was obtained. Amount of chemicals in treatment liquid (air-dried raw material) Sodium percarbonate (as Na ₂ O) 9% Sodium oxalate (as Na ₂ O) 6% β-amylanthraquinone 0.3% Represented by the general formula (1), R is an octyl diphosphonic acid 1.0% MgCl ₂ (as MgO) 0.1%

[0022]

Industrial Applicability According to the present invention, delicate and flexible long fibers can be efficiently produced from agricultural wastes which have not been used as raw materials for raw materials such as high-grade fabrics. Further, the single fiber produced as a by-product in the present invention can be used as pulp.

Claims (7)

[Claims] 1. A plant-based raw material containing a fiber bundle or a fiber bundle collected from the raw material is used as a raw material, which is mildly treated in an aqueous solution containing an alkaline substance and hydrogen peroxide or a hydrogen peroxide generator to provide flexibility. A method for producing a plant fiber, which comprises obtaining a long fiber rich in nature. 2. The method for producing a plant fiber according to claim 1, wherein the aqueous solution contains a chelating agent and an anthraquinone compound. 3. The method for producing plant fiber according to claim 1, wherein the aqueous solution contains a magnesium compound. 4. The method for producing a plant fiber according to claim 1, wherein the aqueous solution contains oxalic acid or a water-soluble salt thereof. 5. The method for producing a plant fiber according to claim 2, wherein at least a part of the chelating agent is diphosphonic acid represented by the following general formula (1). Embedded image (However, R represents an alkyl group having 1 to 11 carbon atoms) 6. The method for producing a plant fiber according to claim 1, wherein the aqueous solution is swirled and / or vibrated. 7. The method for producing a vegetable fiber according to claim 1, wherein the aqueous solution is subjected to high frequency vibration.