JP2002212888A - Method for producing banana pulp for japanese paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a banana pulp excellent as a raw material of Japanese paper, which is friendly to the environment. SOLUTION: A raw hemp of banana is digested in an aqueous solution containing an alkali hydroxide and hydrogen peroxide as a digesting liquid under normal pressure. The digested material is mechanically defibrated to give a banana pump of glossy continuous fiber in an extremely high yield and to simultaneously reduce an environmental load extremely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing pulp for Japanese paper from banana raw hemp.

[0002]

2. Description of the Related Art It has been known that hemp-like crude fibers having a shape similar to abaca (hereinafter referred to as banana raw hemp) are extracted from old banana trees, but this crude fiber is compared with abaca (manila hemp). Since there is no use as hemp such as rope or woven fabric due to poor strength, there is almost no person who collects it, and a large amount of old banana trees have been discarded.

[0003] It has been reported that the banana pulp can be treated at a high temperature with an aqueous solution of sodium sulfite, that is, a so-called neutral sodium sulfite method, in which a long fiber chemical pulp similar to abaca pulp can be obtained in a high yield of about 55%. However, it did not lead to industrialization. The reason was that we couldn't find an application that required banana to be neutral sulfite pulp, required a large-scale reactor to withstand high temperature and pressure for pulp production, and it was not easy to treat pulp waste liquid. Is raised.

[0004] The KP method (craft method) is currently the mainstream of the pulping method. For wood, softwood or hardwood can be pulped regardless of the type of wood, but non-wood KP pulp has excellent strength but poor yield, dark brown color, and large amounts of chlorine bleach for bleaching. It is not easy to take measures against the generation of organic chlorine compounds, and sulfur compounds with extremely bad smell are generated during pulp production, and environmental measures are difficult in small-scale factories. Very few examples are used. In particular, there was no report on industrialization of banana hemp by the KP method or pulping experiments.

[0005] The inventor of the present invention used only pulping of banana raw material under high temperature and high pressure by using a digestion solution (mixed solution of hydrogen peroxide and caustic alkali) of the PA method (hydrogen peroxide-alkali method). Was successful. The banana pulp produced by the PA method has a high yield (about 55%) and is less luster than pulp of Mitsumata (mitsumata) and goose (cancer). Even when bleached, the bleached pulp with high whiteness was easily obtained by bleaching.
In addition, the company developed applications, and was evaluated as an excellent material for the production of Japanese paper and speaker cones, and both demand and mass production were achieved. Unlike the sulfite method and the KP method, the PA method is a pulping method that does not use sulfur, so that no odor is generated. Pulp waste liquor can be subjected to advanced treatment of waste liquor by concentrated combustion, and the resulting ash mainly composed of alkali carbonate has many advantages such that caustic alkali can be simultaneously and easily recovered by causticizing with quick lime. The PA method has also been successfully industrialized.

[0006] However, in the Washi industry, which may be the largest customer for the PA method, it is rather rare that bananas are purchased and compounded from the outside just because the pulp of the PA method is excellent. . Conventionally, the Japanese paper industry manufactures specially-specified paper in very small quantities, so the pulp used is made from kozo, mitsumata, etc., and the optimal pulp that meets the paper specifications is produced each time. It was manufactured and used by traditional techniques using a simple device such as a flat pot.

[0007] Today, the combination of pulp waste liquor condensing and burning and recovering chemicals and energy is supported as a very economical and energy-saving waste liquor treatment system. However, this is a large-scale system, and it is economically difficult to adopt it unless it is a large-scale pulp mill. In wood pulp mills, the daily production is more than 1,000 tons, and in non-wood pulp mills, usually 100 tons or more is common knowledge. However, when manufacturing pulp of at most several tons per day at each paper mill, as in the production of raw pulp for Japanese paper, wastewater treatment is difficult to implement economically. It was not severe.

However, under the circumstance where the domestic wastewater is severely debated on environmental issues, it is feared that the era in which the wastewater of small and medium-sized enterprises including the Washi Industry is left as it is will not continue for a long time. Therefore, in the Japanese paper industry, it was difficult to make a long-term outlook, and this was a major obstacle to development.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for easily producing excellent banana pulp with a low environmental load even in a very small pulp mill attached to a Japanese paper mill.

[0010]

Means for Solving the Problems As a result of continuing intensive studies to solve the above-mentioned problems, the present inventors put banana raw material together with a caustic alkali aqueous solution in a flat pot and boiled it under normal pressure. It was found that softening and mechanical treatment with a beater resulted in long fiber pulp.

That is, based on the above facts, the research has been continued and, without using the chemical pulping method, the combination of steaming with caustic alkali or hydrogen peroxide under normal pressure and mechanical treatment with a beater or the like has been considered. This semi-chemical pulping method makes it possible to obtain high-yield glossy long-fiber pulp suitable for Japanese paper from banana hemp, while at the same time greatly reducing the environmental impact of wastewater. The invention has been completed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As a fiber raw material for pulp, hemp-like fibers (raw hemp) collected from banana trunks (stalks) are used. Normally, hemp can be collected from old trees that are cut down and discarded each time a banana is collected.

The caustic alkali used as the cooking liquor is not limited to sodium hydroxide but may be potassium hydroxide. The same effect can be expected if the amount used is equimolar. At this time, mixing of alkali carbonate is not prevented. When sodium hydroxide is used as a standard, 5 to 40% as NaOH, preferably 1%
The amount is 5 to 25% (hereinafter, the amount of chemicals used is expressed in terms of absolute dry material).

The amount of hydrogen peroxide added is 0.1 as H ₂ O ₂ .
It is 5 to 10%, preferably 1 to 5%.

At the time of steaming, at least one of the following
It is desirable to add more than one species. Water glass and chelates such as DTPA (diethylene. Triamine. Penta. Acetic acidide), EDTA (ethylenediamine. Tetraacetic acid) and diphosphonic acid, and anthraquinone, amyl anthraquinone, -Anthraquinones such as charbutyl anthraquinone. The amount of water glass used is 0.1-3%, preferably 0.3-1%.
Agent is 0.05-2%, preferably 0.1-0.5%
The content of anthraquinones is 0.02 to 0.5%, preferably 0.03 to 0.2%.

The liquid ratio is 1.5 to 10 liter / kg.
For gas-phase cooking, it is preferably 2-3 liters / kg, and for liquid-phase cooking, it is preferably 5-8 liters / kg.

The cooking time is 0.5 to 5 hours under normal pressure, preferably 0.5 to 1.5 hours for gas phase cooking, and preferably 1 to 3 hours for liquid phase cooking.

If the raw banana after steaming is subjected to a mechanical fibrillation treatment using a beater, an edge runner or the like, it becomes a single fiber, and the pulp is produced in a high yield and with a low environmental load. Can be obtained at Although banana pulp is a long-fiber pulp with gloss and high whiteness, the fibers are less entangled during defibration, so that those which are usually used in efficient paper mills such as a holly and a niagaraviter can be used. It is not always necessary to use an inefficient naginata beater. In particular, when it is desired to prevent fiber entanglement and obtain the strength of the paper, defibration and beating by using an edge runner are effective.

The use of the concentrated combustion method for the treatment of pulp waste liquid makes it possible to remove organic substances at once. Equipment for chemical treatment such as treatment and coagulation sedimentation method is small.

[0020]

The present invention is easy to carry out, and a great effect can be expected.

Although the present invention is a type of semi-chemical pulping process, the production requires little or no new equipment. In addition, since the reaction is carried out at normal pressure, there is no particular use as a pressure vessel even if an earth pot is included, and maintenance and inspection are extremely easy. With a very high yield of about 75%,
Banana long-fiber pulp with gloss and high whiteness can be supplied on a home-made basis, which helps to activate domestic traditional Japanese paper manufacturers. Further, by increasing the yield, the amount of organic substances eluted in the waste liquid can be reduced to half or less, and the wastewater treatment can be facilitated, and the environmental load can be reduced to about 1/3 at a stroke. If a potassium base is used during steaming, the pulp waste liquid naturally becomes a potassium base.
There is also a fertilizer effect, and it is also possible to eliminate salt damage caused by sodium caused by sodium-based waste liquid on downstream arable land.

In addition, since the process and equipment are simple, it is expected that even in the southern banana-producing countries, a new integrated small-sized pulp and paper mill will be started up and jobs will be created accordingly.

As a secondary matter, about 500,000 tons of banana hemp are collected as pulp raw material from a large amount of abandoned trees generated with 45 million tons of bananas produced in 120 southern countries. In that case, new employment can be expected.

[0024]

The present invention will be further described with reference to the following examples. However, the present invention is not limited only to the embodiment. Unless otherwise specified, "%" indicates% by weight. The pulp yield refers to the weight percent of air-dried raw material (as moisture 15%) based on air-dried pulp (as moisture 10%).

[0025]

Example 1 100 kg of high-quality banana raw hemp collected from an old banana tree was put into a flat pot, and as a cooking solution, water was added to 15 kg of sodium hydroxide to make a 600 liter cooking solution, and steamed at 100 ° C. for 2 hours. did. After steaming, the mixture was treated with a hender for 30 minutes to disintegrate it, and 3% of hydrogen peroxide (in terms of 100%) and 1% of sodium hydroxide were added to the obtained pulp, and the mixture was allowed to stand at a liquid ratio of 10 L / kg for one day and night. C. S.
F. (Canadian freeness) 74.4 kg of bleached banana pulp having 680 ml and whiteness of 61.4% was obtained. The obtained banana pulp was further beaten with a hender, and the breaking length was 6.9 km, the specific burst strength was 4.5, and the specific tear strength was 18.
0 and the result of the sieving test is 14 mesh on 3
7.2%, 28 mesh on 20.8%, 100 mesh on 9.9%, 200 mesh on 14.2%, 20
0 mesh pass was 17.9%.

[0026]

Example 2 100 kg of high-quality banana raw hemp collected from an old banana tree was put into a 1 m stainless steel earth pot,
21 kg of potassium hydroxide and hydrogen peroxide (100%
2.5 kg and 85 g of anthraquinone were added to water and added as 300 liters of a cooking liquid.
Steamed while rotating at 1.5 ° C. for 1.5 hours. After steaming, the mixture was treated with an edge runner for 60 minutes. S. F. 78.3 pulp of 520 ml with glossy whiteness of 65%
kg. It was found that the solid content of hemp in the pulp waste liquid can be reduced to 34% at a stroke as shown in the following formula, as compared with the conventional pulp having a yield of 55%. 45: 55 = 0.8 for a conventional 55% yield chemical pulp
2 in the case of the pulp having a yield of 78.3% according to the present invention.
1.7: 78.3 = 0.28, and the reduction rate is 0.2
8 / 0.82 = 0.34 can be greatly reduced. The obtained banana pulp further showed a breaking length of 7.2 km, a specific burst strength of 4.7 and a specific tear strength of 220. The results of the sieving test were as follows: 14 mesh on 40.3%, 28 mesh on 22.6 %, 100 mesh on 13.2%, 20
12. 0 mesh on 10.9%, 200 mesh pass
It was 0%.

Claims (2)

[Claims] 1. An aqueous solution of caustic alkali is used as a cooking liquid, and banana raw hemp is immersed before steaming and then steamed under normal pressure, or immediately steamed under normal pressure, and then beaded.
A method for producing banana pulp for Japanese paper, which comprises mechanically defibrating with a tar or an edge runner. 2. A method according to claim 1, wherein hydrogen peroxide is added to an aqueous solution of caustic alkali as a cooking liquid, and at least one of water glass, a chelating agent and anthraquinones is optionally added as a cooking aid. Production method of banana pulp for Japanese paper.