WO2007004757A1

WO2007004757A1 - Process for producing pulp utilizing bamboo and pulp and papers produced using the same

Info

Publication number: WO2007004757A1
Application number: PCT/KR2005/002118
Authority: WO
Inventors: Kwon-Hyok Lee; Jong-Myoung Won
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-06-30
Filing date: 2005-07-04
Publication date: 2007-01-11
Anticipated expiration: 2007-12-30
Also published as: KR100547492B1

Abstract

Disclosed are a technique for producing high quality paper-making pulp capable of replacing wood pulp, utilizing bamboo and paper products produced using the same. The present invention can be applied to techniques for producing a variety of paper-making pulps which can be used in production of industrial papers, printing and writing papers, thin wrapping papers, toilet papers and special purpose papers from bamboo, and processes for producing a variety of paper products from the same. The present invention relates to a process for producing pulp utilizing bamboo, which is capable of producing pulp under mild conditions by facilitating penetration of liquid chemicals in chemical pulp production, is capable of simplifying manufacturing processes, and is also capable of maximizing pulp yield and minimizing weakening of pulp fibers, thereby maximizing pulp quality; and pulp and papers produced using the same.

Description

[DESCRIPTION]

[invention Title]

PROCESS FOR PRODUCING PULP UTILIZING BAMBOO AND PULP AND PAPERS PRODUCED USING THE SAME [Technical Field]

The present invention relates to a technology for producing high-quality paper-making pulp capable of substituting for wood pulp, and paper products, using a bamboo, and encompasses a technology for producing various paper-making pulps usable in the production of industrial paper, printing and writing paper, thin wrapping paper, toilet paper, non-woven fabric and special purpose paper, from bamboos, as well as a method for producing various papers from said pulps. The method according to the present invention can produce chemical pulp in mild conditions by facilitating the penetration of liquid chemicals in the production of the pulp, simplify a process, maximize pulp yield, and minimize the weakening of pulp fiber to maximize pulp quality. Also, the present invention relates to pulp produced using said method.

[Background Art]

Generally, papermaking pulps are recognized to be produced using wood.

In other words, because the papermaking pulps consist mostly of wood pulps, and it has recently became a great problem to produce the papermaking pulp while conserving forests due to the lack of wood resources and maintaining the environment, effects to produce the pulps using non-woody plant fibers and the like are being conducted. Such non-woody plants include paper mulberry bast fibers, hemps, cottons, and Manila hemps, and Korean Patent Publication Nos. 98-9651 and 93-2604 disclose a method for producing pulp using rice-straw. All such efforts can be considered as efforts to conserve trees, which can prevent environmental pollution.

In other words, these efforts aim to conserve trees by absorbing pollutants and carbon dioxide contained in the atmosphere through photosynthetic action while producing and supplying oxygen.

The development of industry and civilization really led to a great improvement in the quality of life of mankind, but involved a rapid increase in energy use, so that the emission of greenhouse gas was also rapidly increased, and thus the contamination of the global environment and side effects thereof became very severe.

In typical examples thereof, the depletion of the ozone layer in the South Pole becomes very rapidly severe, and misfortunes caused by a rapid change in weather, global warming and ecosystem destruction occur in the whole world.

Such environment pollution phenomena very rapidly progressed to reach a state that threatens the survival of mankind, and thus the Tokyo Protocol on the reduction of greenhouse gas emissions, which has been delayed due to the noncooperation of some of highly developed countries, became effective .

Accordingly, in manufactures in various countries, efforts to reduce greenhouse gas emissions are urgently required, and in severe cases, additional expenses for purchasing greenhouse gas emission rights are expected. One means for solving this problem, which has recently received great attention, is a non-woody plant that eliminates the need for the felling of wood.

In other words, when this non-woody plant is used to produce pulp, there will be a great advantage in that wood, which is consumed in large amounts, needs to be felled.

Among the non-woody plants, a bamboo, which has recently attracted attention and is used as a raw material in the present invention, is produced in large amounts in Southeast Asia countries such as China and Myanmar and sufficiently grows to a usable degree only within about five months .

However, the use of the bamboo has shortcomings in that, because the compact structure of the bamboo is not considered, the pulping of the bamboo is not satisfactorily achieved, large amounts of chemicals and energy are consumed, and a bleaching process is conduced in strong conditions to reduce yield and to cause the decomposition and destruction of fiber, making the fiber weak. A chlorine bleaching process using elemental chlorine provides the cause of dioxin generation.

Also, because bleaching powder that acts as the cause of the corrosion of an apparatus is used as a bleaching chemical, the durability of the production apparatus is highly problematic.

In addition, this processing problem acts as the cause of increasing chemical amount, energy consumption and production cost per unit pulp production.

Methods for producing papermaking pulp and paper using a bamboo, like the present invention, were also developed in - A -

the prior art, but have not been widely used, the reason for which will now be described.

Even though the bamboo has a very compact and hard structure, a bamboo chip having a thickness of 3.2 mm and a length and width of 19 mm was prepared in the prior art. Because the penetration of liquid chemical into the chip was difficult, the cooking of the chip was not sufficiently performed, thus making bleaching difficult.

The application of the prior art as described above cannot efficiently produce pulp, reduces the quality of pulp and is very disadvantageous in environmental terms.

Japanese Patent 3,184,993 invented by Kikuchi Shingo is very disadvantageous in terms of pulp yield, pulp quality and the consumption of liquid chemicals, because bamboo leaves and stalks are all used. Also, the technology of the household industrial level, which is difficult to perform mass production, is applied, because the bamboo is simply treated with an alkali solution in atmospheric conditions.

The paper making method in said Japanese Patent is a method for producing a kind of fiber mat for use in special applications such as forest bath, deodorization, air purification and wall papers using household industrial means and is entirely different from a paper production method for mass production, which is suggested in the present invention. Also, in US Patent No. 4,857,145 invented by Eduardo J. Villavicencio, a shredder is used to prepare bamboo chips having a length of 10-25 cm or more, which are then chemically digested.

In this case, although it is possible to minimize damage to fibers as stated by the inventor, the fibers require a wide space for the storage thereof, because their volume is very large. Also, the fibers cannot be treated in large amounts during a digestion process.

Furthermore, because the thickness of the prepared bamboo chips is large, the fibers are pre-impregnated with black liquor or digestion chemicals at high pressure to facilitate the digestion of chemicals. For this reason, additional processes, facilities and energy are required.

Also, the dissociation of the fibers is induced by treatment such as an explosion process by repeating pressurization and depressurization in a digestion process.

This pulping process is unsuitable for the mass production of papermaking pulp, because it requires much time and results in a significant reduction in pulp quality. Also, because the pulp discharged from a digester is treated with a refiner so as to disintegrate it into a fiber state, the fibers can be significantly damaged. Also, the pulp shows properties similar to those of semi-chemical pulp, and it is optionally carried out to bleach the pulp. Accordingly, the pulp produced in said US Patent can be used as a raw material for the production of low-grade paper and industrial paper, but is not suitable for the production of high-grade printing and writing paper, toilet paper, thin paper, newsprint paper or medium-quality paper. [Disclosure]

[Technical Problem]

The present invention has been made to solve the problems occurring in the prior art, and it is an object of the present invention to provide a method for producing high- quality papermaking pulp capable of substituting for wood pulp, and paper products, using a bamboo. More specifically, it is an object of the present invention to provide a method for producing various papermaking pulps using a bamboo, which makes it possible to produce the pulp in mild conditions by facilitating the impregnation of liquid chemicals into the pulp, simplify a process, maximize the pulp yield and minimize the weakening of the pulp fiber to maximize the quality of the pulp, as well as pulp prepared using said method, and a method for producing paper products from said pulp. The pulp, which is produced in the inventive method, can be used to produce various paper products, including industrial paper, printing and writing paper, thin wrapping paper, toilet paper, non-woven fabric and special purpose paper. [Technical Solution]

To achieve the above object, the present invention provides a method for producing pulp from a bamboo, the method comprising: a step of removing a leaf from a bamboo and splitting and cutting the leaf-removed bamboo to make bamboo chips; a step of screening the cut bamboo chips to filter out small fragments or impurities from the chips and washing the chips with water to remove contaminants from the bamboo chips; a step of cooking the screened bamboo chips, in which the bamboo chips are introduced into a digester, the ratio of a chemical liquor consisting of water, alkali and anthraquinone to the weight of the bamboo chips is adjusted to 1:3.5-6.0 (bamboo: chemical liquor), and the bamboo chips are cooked in the digester at high temperature, thus softening and pulping the bamboo chips; a step of cleaning the cooked pulp using a centrifugal cleaner so as to remove contaminants introduced together with the bamboo; a step of screening the cleaned pulp, in which contaminants are removed from the cleaned pulp using a pressure screen, and an incompletely cooked of the pulp is fed back into the digester; a step of washing and thickening the screened pulp, in which a decker is used to wash the pulp, thus removing the chemical liquor, and to squeeze water, thus thickening the pulp; and a step of using the thickened pulp to produce unbleached chemical and semi-chemical bamboo pulp for industrial paper or liner paper for corrugated boards.

In another embodiment, the present invention provides a method for producing bleached chemical bamboo pulp for the production of tissue paper, wood-free paper, art paper or toilet paper, and a method for producing refiner mechanical pulp for the production of newsprint paper or medium-quality paper, each of the methods having modifications of said method for producing the unbleached chemical and semi- chemical bamboo pulps for industrial paper or liner paper for corrugated boards. In still another embodiment, the present invention provides a method for producing industrial paper or liner paper for corrugated boards, the method comprising: a step of disintegrating the unbleached chemical or semi-chemical bamboo pulp produced according to said method; a step of refining the disintegrated pulp; a step of adding chemicals

(sizing agent, retention agent, strengthening agent and other additives) to the refined pulp; a step of screening the pulp having the chemicals added thereto; a sheet forming step of making the screened pulp into a product (web) in the form of paper or paperboard; a pressing step of pressing the web obtained in the sheet forming step to remove water; a drying step of further removing water from the pressed web; a calendering step of making the thickness of the paper or paperboard uniform; a step of slitting and cutting the calendered paper into a sheet or roll and packing the sheet or roll.

In addition, the present invention provides a method for producing tissue paper, wood-free paper, art paper or toilet paper from bleached chemical bamboo pulp, and a method for producing newsprint paper or medium-quality paper from refiner mechanical pulp, each of the methods having modifications of said method for producing industrial paper and liner paper for corrugated boards.

[Description of Drawings] FIG. 1 is a flow chart showing processes for producing bamboo pulps according to the present invention. [Best Mode]

The present invention relates to methods for producing papermaking pulps using a bamboo, as well as pulps produced using said methods, and methods for producing papers using the pulps. The production methods have great characteristics and will now be described in detail.

Among the methods for producing pulps using a bamboo, the steps of the method for producing unbleached chemical and semi-chemical pulp for industrial paper or liner paper for corrugated boards will now be sequentially described with reference to FIG. 1.

Specifically, the method for producing unbleached chemical and semi-chemical pulp for the production of industrial paper or liner paper for corrugated boards comprises: a first step of removing a leaf from a bamboo and splitting and cutting the leaf-removed bamboo; and a second step of screening the cut bamboo chips to filter out small fragments or impurities from the bamboo chips and washing the bamboo chips with water to remove contaminants from the bamboo chips .

Also, the method comprises: a third step of cooking the washed bamboo chips, in which the bamboo chips are introduced into a digester, the ratio of a chemical liquor consisting of water, alkali and ^"anthraquinone to the weight of the bamboo chips is adjusted to 1:3.5-6.0 (bamboo: chemical liquor), and the bamboo chips are cooked in the digester at high temperature, thus softening and pulping the bamboo chips; and a fourth step of cleaning the cooked pulp using a centrifugal cleaner to remove contaminants introduced together with the bamboo .

If semi-chemical pulp is to be produced, the third step comprises conducting the cooking process in mild conditions and then conducting refining instead of the cleaning. Also, the method comprises: a fifth step of screening the chips, in which contaminants are removed from the cooked pulp using a pressure screen, and an incompletely cooked portion of the pulp is fed back into the digester; and a sixth step of washing and thickening the chips, in which a decker is used to wash the pulp, thus removing the chemical liquor, and to squeeze water from the pulp, thus thickening the pulp.

In addition, the method comprises: a seventh step of forming a sheet from the washed and thickened pulp and drying the sheet, thereby producing unbleached chemical and semi- chemical pulp for industrial paper or liner paper for corrugated boards.

The above-described steps will now be described in further detail. In the third step of cooking the bamboo chips, the amount of alkali (as Na₂O) added to water is 10- 30 % based on the oven-dry weight of the bamboo chips (i.e., mass excluding the content of moisture in the bamboo chips), and the anthraquinon (AQ) is added in an amount of 0.01-2%.

In other words, the bamboo leaf contains a large amount of extracts unnecessary to produce pulp, but has a small amount of essential fibrous material.

Thus, because the bamboo leaf is of help to prepare pulp, but rather can act as the cause of increasing the consumption of chemicals, the bamboo leaf is removed before introducing the bamboo into a process for producing the pulp.

In other words, in the inventive method for producing the bamboo pulp, the bamboo leaf is not used and only the bamboo stalk is used.

Then, a longitudinal splitting step of longitudinally splitting the bamboo to a width of 1.5-3 mm is conducted.

Due to the compact structure of the bamboo, the impregnation of chemicals into the bamboo is significantly difficult compared to wood.

Thus, the production of the pulp must be started with the crushing of the bamboo. For this purpose, the bamboo is first longitudinally split into half, and the split bamboo is additionally split to a narrower width.

In this step, the bamboo is preferably split to a width of 1.5-2.0 mm. This longitudinal splitting is a significantly characteristic step of the present invention, and when the bamboo is split at random without considering orientation, fibrous material will not be uniformly split, but rather the fibrous material itself can be broken. This reduces the strength of the produced pulp to reduce the quality thereof.

For this reason, in the inventive production method, the bamboo is used after it is longitudinally split several times to have narrow width. It is also possible to use a method of splitting the bamboo in a one-step process using a device mounted with a plurality of blades.

Then, the step of transversely cutting the longitudinally split bamboo to a length of 10-30 mm is conducted.

In other words, in order to produce small bamboo chips which are easily filled and packed in a digester, the split bamboo is transversely cut to a length of 10-30 mm using a blade cutter. If the length of the bamboo chips is too large, they cannot be effectively packed into the digester, and if the bamboo is cut to an excessively short length, large damage to fiber can occur, resulting in the reduction in the strength of the pulp. Then, the second step of screening the cut bamboo chips to filter out small fragments or impurities from the chips and of washing the chips with water to remove contaminants from the chips is carried out.

In other words, even if small fragments which are generated in the step of cutting the bamboo are prepared into pulp, the pulp is in a state in which the fibrous material was broken. Thus, these small fragments can weaken the strength of the pulp, incre'ase the consumption of chemicals, and adversely affects dehydration in a papermaking machine. Also, contaminants introduced during the cutting step are not of any help to produce the pulp.

Accordingly, if these small fragments and contaminants are all used in the production of the pulp, they will greatly reduce the yield (production rate) of the pulp and will adversely affect the quality of the pulp. For this reason, these are removed by screening.

Also, in other words, the contaminant, dust and the like attached to the bamboo chips are removed with water.

This can reduce the consumption of unnecessary chemicals in a cooking process and allows pure pulp to be obtained, thus improving the quality of the produced pulp.

Then, the third step is carried out, in which the bamboo chips are introduced into a digester, the ratio of a chemical liquor consisting of water, alkali and anthraquinone to the weight of the bamboo chips is adjusted to 1:3.5-6.0 (bamboo: chemical liquor), and the bamboo chips are cooked in the digester at high temperature, thus softening and pulping the bamboo chips .

The use of a prior sulfite process for the cooking of the bamboo chips has problems in that the fiber becomes weak and the yield of the pulp is low.

Thus, in the present invention, a soda-ΛQ process is applied in order to promote delignification and to prevent the decomposition of hemicellulose, thus increasing the yield and quality of the pulp. In other words, the soda-AQ process comprises adding a liquor consisting of alkali (mainly NaOH) , anthraquinone and water in a liquor ratio of 3.5-6.9 : 1 with respect to the oven-dry weight of the bamboo chips. Also, in the soda-AQ process, the amount of alkali (as Na₂O) added to water is preferably 10-30 % based on the oven- dry weight of the bamboo chips (i.e., mass excluding the content of moisture in the bamboo chips) , and the anthraquinon (AQ) is preferably added in an amount of 0.01-1%. The cooking temperature in this cooking step is preferably 130-210 "C, and the cooking time is preferably controlled within the range of 90-120 minutes depending on the polymerization degree and the quality of pulp to be produced. As used herein, the term "oven-dry weight" means the mass of the bamboo chips that excludes the content of moisture in the bamboo chips.

Then, the fourth step of cleaning the bamboo chips using a centrifugal cleaner so as to remove contaminants introduced together with the bamboo is conducted.

In other words, the centrifugal cleaner is used to remove contaminants introduced in the process together with the bamboo.

Then, a fifth step of screening the pulp is conducted, in which contaminants are removed from the cooked pulp using a pressure screen, and an incompletely cooked portion of the pulp is fed back into the digester.

In other words, non-disintegrated fibrous portions or contaminants are removed using the pressure screen. A portion passed through the screen is sent to a subsequent process, whereas a rejected portion remaining on the screen is filtered through a vibrating screen, a rejected portion remaining on the vibrating screen is wasted, and a fibrous portion or an incompletely cooked portion is sent back into the digester.

A sixth step of washing and thickening the pulp is conducted, in which a decker is used to wash the pulp, thus removing the chemicals from the pulp, and to squeeze water from the pulp, thus thickening the pulp. The decker (not shown) is a machine that serves to wash the pulp and, at the same time, to thicken the pulp by squeezing water. Using this decker, the pulp is washed and thickened to a concentration suitable for the next step.

In this step, the washing operation is repeated at least three times in order to remove the remaining chemicals, fine powders and parenchyma cells as much as possible.

Then, a seventh step of forming the washed pulp into a sheet or roll is conducted, in which the washed pulp is made into a sheet and dried, thus completing the production of unbleached chemical and semi-chemical pulp for industrial paper or liner paper for corrugated boards.

To produce unbleached pulp for the production of industrial paper and liner paper, which have a more excellent quality, the cooking step in the above-described method is preferably carried out in the following conditions milder than those for the production of bleached chemical pulp: the content of active alkali: 12-14%; the content of AQ: 0.01 -

1%; liquor ratio: 3.5-6.9; cooking temperature: 130 - 150 ^°C ; and cooking time: 90-120 minutes. Such conditions were determined through many experiments conducted by the applicant.

Furthermore, said unbleached chemical and semi-chemical pulp for the production of industrial paper or liner paper for corrugated boards, bleached chemical pulp for the production of tissue paper, wood-free paper, art paper or toilet paper, and refiner mechanical pulp for the production of newsprint paper or medium-quality paper, can undergo a slitting, cutting and packing step.

However, it is preferable that the pulps should not be subjected to this slitting, cutting and packing step and should be immediately sent to a papermaking process to make paper and paperboard products.

It is to be understood that, if a pulp production factory and a paper production factory are separately placed, the slitting, cutting and packing step must be carried out.

The pulps are generally packed in the form of rolls or sheets.

In other words, it is preferable that the pulp produced in the pulping process is immediately fed into a papermaking process for use as a papermaking raw material without undergoing a drying process.

The bamboo pulp fiber has a structure and dimension different from those of wood pulp.

Such properties can be advantages in some terms depending on the intended use of the pulps, but can also be disadvantages in other terms.

Thus, depending on the quality requirement of paper to be produced, the blending or treatment of the pulps is required. The method for producing the unbleached chemical and semi-chemical bamboo pulp for the production of industrial paper and liner paper has been described above. Thus, a step of completing the production of bleached chemical pulp for use in the production of tissue paper, wood-free paper, art paper, non-woven fabric, special purpose paper and toilet paper will now be described.

Specifically, the method for producing bleached chemical pulp for the production of tissue paper, wood-free paper, art paper or toilet paper, using a bamboo, comprises: a first step of removing a leaf from a bamboo and splitting and cutting the leaf-removed bamboo; and a second step of screening the cut bamboo chips to filter out small fragments or impurities from the chips and washing the chips to remove contaminants from the chips. Also, the method comprises: a third step of cooking the washed bamboo chips, in which the bamboo chips are introduced into a digester, the ratio of a chemical liquor consisting of water, alkali and anthraquinone to the weight of the bamboo chips is adjusted to 1:3.5-6.0 (bamboo: chemical liquor), and the bamboo chips are cooked in the digester at high temperature, thus softening and pulping the bamboo chips; and a fourth step of cleaning the cooked pulp using a centrifugal cleaner so as to remove contaminants introduced together with the bamboo. Also, the method comprises: a fifth step of screening the cleaned pulp, in which contaminants are removed from the cooked pulp using a pressure screen, and an incompletely cooked portion of the pulp is fed back into the digester; and a sixth step of washing and thickening the pulp, in which a decker is used to wash the pulp, thus removing the chemical liquor from the pulp, and to squeeze water from the pulp, thus thickening the pulp.

In addition, the method comprises: a seventh step of bleaching the thickened pulp; and a eighth step of forming the bleached pulp into a sheets or roll and drying the sheet or roll, thereby producing bleached chemical pulp for the production of tissue paper, wood-free paper, art paper or toilet paper.

In other words, the method for producing the bleached chemical pulp for the production of tissue paper, wood-free paper, art paper, special purpose paper or toilet paper is the same as the above-described method for producing the unbleached chemical and semi-chemical pulp for the production of industrial paper or corrugated board liner paper with respect to the first step to the sixth step, but it performs the cooking step in conditions stronger than those of the production of the unbleached chemical and semi-chemical pulp and comprises the seventh step of bleaching the pulps.

This is because the industrial paper and corrugated boards need not to be bleached, but tissue paper, wood-free paper, art paper, special purpose paper or toilet paper must have a good texture and excellent colorful beauty sensations.

Thus, regarding the method for producing the bleached chemical pulp for the production of tissue paper, wood-free paper, art paper, special purpose paper or toilet paper, only the step of bleaching the pulp will be described.

In other words, in the seventh step of bleaching the pulp, which is very important in the present invention, is an ECF (elementary chlorine free) or TCF (total chlorine free) bleaching process is used in order to eliminate environmental problems such as the generation of environmental hormone dioxin.

As bleaching stages used in this step, DED, DEDD, DEDP,

DEZP, DEOP, DEOZ and PEOZ can be selectively applied. A bleaching process, the number of bleaching stages, and bleaching conditions, are determined depending on the degree of required bleaching.

In the above description of the bleaching stages, D means chlorine dioxide bleaching, E means alkaline extraction, P means peroxide bleaching, 0 means oxygen bleaching, and Z means ozone bleaching.

If the content of metal ions in the pulp is high, the metal ions will be inactivated by treating the pulp with a chelating agent (EDTA, DTPA, DTPMPA, etc.) to increase bleaching efficiency before conducting the bleaching of the pulp.

Herein, the chelating agent is a chemical for making the reactivity of metal ions impotent, and if large amounts the metal ions are present in the pulp, they will remarkably deteriorate the performance of a bleaching chemical used for bleaching.

For this reason, if the content of the metal ions is large so that it reduces bleaching efficiency, the pulp is treated with the chelating agent before conducting the bleaching of the pulp.

As an example of a bleaching method using the bleaching stages, the bleaching stages of DEDD indicate that bleaching is conducted in four sequential steps of: (1) chlorine dioxide bleaching, (2) alkaline extraction, (3) chlorine dioxide bleaching, and (4) chlorine dioxide bleaching. In other words, various bleaching stages listed above indicate that a pulp producer may selectively the bleaching stages depending on the brightness or chemical purity required in the pulp to be produced, or the preference of a worker.

Regarding the purpose for increasing the number of the bleaching stages, when the brightness or chemical purity is greatly required, the number of the bleaching stages may be increased or the amount of chemicals used may be increased. Also, even if the same level is required, a method of reducing the amount of a chemical used in each stage and increasing the number of the stages can be used in order to minimize adverse effects on pulp (pulp damage and decomposition, etc) . Accordingly, even if the quality of the same level is required, it is possible to control the number of the bleaching stages or the amount of chemicals used, and it is difficult to express this control as an absolute numerical value, because the state of pulp supplied into the bleaching process varies depending the degrees of pulping or cooking conducted in the above-described steps.

However, when the pulp is bleached, it is preferable that the content of lignin in the pulp produced in the digester be first measured and, based on the measured content, the amount of addition of bleaching chemicals be calculated so as to increase or decrease the amount depending on the required quality.

Thus, the present invention can prevent the generation of dioxin, an environmental pollutant, using said bleaching agent, and has excellent bleaching effects. In the most embodiment of the present invention, the method for producing the bleached chemical pulp for the production of wood-free paper, art paper, non-woven fabric, special purpose paper or tissue paper comprises conducting the cooking process in the following conditions and the ECF or TCF bleaching process: the content of active alkali: 16 - 20%; the content of AQ 0.01-1%; liquor ratio: 3.5-6.0; cooking temperature: 150-180 ^°C ; and cooking time: 120 - 200 minutes. Also, the yield of the produced papermaking pulp, the characteristics of the fibers, the papermaking characteristics, etc., are controlled through the combination of cooking conditions, bleaching conditions and methods.

In addition to the method for producing the unbleached and semi-chemical pulp for the production of industrial paper or corrugated board liner paper and the method for producing the bleached chemical pulp for the production of tissue paper, wood-free paper, art paper, non-woven fabric, special purpose paper or toilet paper, the present invention also provides a method for producing refiner mechanical pulps for the production of newsprint paper or medium-quality paper.

Thus, the steps of the method for producing refiner mechanical pulp for the production of newsprint paper or medium-quality paper will be sequentially described in detail. This method comprises: a first step of removing a leaf from a bamboo and splitting and cutting the leaf-removed bamboo; and a second step of screening the cut bamboo chips to filter out small fragments or impurities from the chips and washing the chips with water to remove contaminants from the chips. Also, the method comprises: a third step of primarily refining the washed bamboo chips, in which the bamboo chips are ground in a disc refiner; and a fourth step of screening the refined bamboo chips, in which contaminants are removed from the bamboo chips using a pressure screen, and an incompletely defibrated portion of the chips is fed back into the disc refiner.

Also, the method comprises: a fifth step of secondarily refining the defibrated pulp, in which the defibrated pulp is further ground; and a sixth step of screening the refined pulp, in which contaminants are removed from the pulp using a pressure screen, and an incompletely defibrated portion of the pulp is fed back into the disc refiner.

In addition, the method comprises: a seventh step of cleaning the defibrated pulp, in which contaminants introduced together with the bamboo are removed using a centrifugal cleaner; and an eighth step of forming the cleaned pulp into a sheet and drying the sheet.

In other words, the sequence of the steps of this method is substantially the same as that of the above- described method for producing unbleached chemical and semi- chemical pulp for the production of industrial paper or corrugated board liner paper and as that of the above- described method for producing bleached chemical pulp for the production of tissue paper, wood-free paper, art paper, non- woven fabric, special purpose paper or toilet paper, however, it is different in that the cooking step is not carried out and the two refining steps are additionally conducted.

Thus, only the refining steps will be additionally described herein. As used herein, the term "refining step" refers to a step of producing refiner mechanical pulp, in which the bamboo chips resulting from the previous washing step are ground in the disc refiner to produce the pulp.

This refining step in the present invention is repeated two times to grind the chips into very fine pieces.

Accordingly, in this method, the prepared, screened and washed bamboo chips are defibrated using the refiner so as to prepare refiner mechanical pulp for the production of newsprint paper and medium-quality paper. In this case, if the high brightness is required in the pulp, single-stage or two-stage peroxide bleaching is preferably carried out.

Also, the present invention also provides articles produced according to all the above-described pulp production methods, i.e., pulps produced using a bamboo.

Also, the pulps are made into the form of a sheet or roll, in which the sheet pulp has a thickness of 0.1-3 mm, and the roll pulp is obtained by winding a web having a thickness of 0.1-1.5 mm. In other words, the sheet or roll pulp is an intermediate product, which will be introduced into a papermaking process to produce paper as described above.

Thus, if a pulp production factory and a papermaking factory are far away from each other, the pulp must be transported in a state in which it was packed in the form of a sheet or roll as described above. However, if the factories are integrated factories, the pulp needs not to be specially packed.

Methods for producing paper products from the intermediate products produced as described above will now be described in a manner classified according to the kind of the paper products.

First, a method for producing industrial papers or corrugated board liner paper using said unbleached chemical and semi-chemical bamboo pulp will be described.

Specifically, the method for producing the industrial paper or corrugated board liner paper comprises: a step of disintegrating the unbleached chemical and semi-chemical bamboo pulp; and a step of refining the disintegrated pulp. Also, the method comprises: a step of adding chemicals (sizing agent, retention agent, strengthening agent and other additives) to the refined pulp; and a step of screening the pulp.

Also, the method comprises: a sheet forming step of making the screened pulp into a product (web) in the form of a paper or paperboard; and a pressing step of pressing the web obtained in the sheet forming step to remove water from the web.

Also, the method comprises: a drying step of further removing water from the pressed web; and a calendering step of making the thickness of the paper or paperboard uniform.

In addition, the method comprises a step of slitting and cutting the dried and calendered paper into a sheet or roll and packing the sheet or roll. Hereinafter, each of said steps will be described in further detail.

First, in the step of disintegrating the unbleached chemical and semi-chemical bamboo pulp, the pulp sheet is repulped or disintegrated into individual fibers using a pulper or hydrapulper. This repulping or disintegration step may also be omitted, if the pulp is not made into the sheet in the pulp production process and is immediately fed to a papermaking process through pipe lines and the like. In the step of refining the disintegrated pulp, wood pulp and bamboo pulp are refined using a disc refiner or cone refiner according to conditions required for the desired paper in order to control the structural, physical and optical properties of the paper. Chemical pulp of broadleaf trees is usually refined at an SEL of about 0.1-5.0 Ws/m.

However, bamboo pulp needs to be treated in a manner different from wood pulp, because it has a relatively low lignin content, and its fiber is thin. Thus, the bamboo pulp is either refined at a weak SEL (specific edge load; index indicative of the intensity of energy applied from the refiner to the pulp) of 0.01-2.5 Ws/m depending on the required properties of paper to be produced, or treated using a deflaker. Refiners suitable for refining the bamboo pulp at low SEL include multidisk refiner, Conflo and the like.

On the other hand, if more refining is required, the refining of the pulp is conducted at a higher SEL.

In the step of adding chemicals (sizing agent, retention agent, strengthening agent and other additives) to the refined pulp, the addition of wet chemicals and additives is performed to adjust a process and to satisfy the properties of paper according to the kind and intended use thereof. In the case of industrial paper, liner base paper, toilet paper and thin wrapping paper, any filler is not used, and the addition of chemicals is adjusted only depending on required size degree, wet strength or dry strength.

Examples of a chemical, which can be used for the adjustment of sizing degree, include rosin emulsion, AKD, ASA and the like, and examples of a wet strength agent, which can be used in the present invention, include urea resin, melamine resin, polyamide epichlorohydrin, acrylamide glyoxal and the like. This chemical is added in an amount of 0.1-3% depending on required wet strength or dry strength.

In the case of wood-free paper, coated base paper, newsprint paper and medium-quality paper, a filler is used in an amount of 10-30% for the improvement of printing quality. Examples of the filler, which can be used in the present invention, include calcium carbonate, activated clay, and titanium dioxide.

Examples of the sizing agent, which can be used in the present invention, include rosin emulsion, AKD, ASA and the like. For the retention of the sizing agent and the filler, microparticle systems (e.g., cationic starch, PAM, bentonite, colloidal silica, organic microparticles, etc.) are used.

Also, the screening step is performed to break aggregates formed in a paper stock preparation process or pipe lines for supplying the paper stock to a papermaking machine and to remove lumps, which are not disintegrated, before supplying the paper stock to the papermaking machine. This screening step is usually performed just before the papermaking machine so as to pass the paper stock. Then, the sheet forming step for producing the paper- or board-like product is a process in which the raw material subjected to the paper stock preparation process is made into the form of a web.

Then, the pressing step of pressing the web formed in the sheet forming step to remove water from the web is performed and will now be described in detail.

Specifically, the pressing step serves to remove water from the web formed in the sheet forming step, make the web more compact and facilitate the bonding between the fibers. In this step, it is preferable to remove water as much as large within the range in which the quality of the product is not deteriorated. This reduces the use of steam in a drying section to increase economy.

However, the pressure used in this pressing step greatly varies depending on the kind of paper.

In the case of paperboard, toilet paper and the like, a pressure lower than that in other printing and writing papers or industrial papers is applied, because a bulk property is important . Then, the drying step of further removing water from the web passed through the pressing step is carried out, in which water in the web passed through the sheet forming step and pressing step is further removed to impart the inherent property of paper or paperboard. Then, in the inventive method, the calendering step of making the thickness of the paper or paperboard uniform is carried out.

The calendering step serves to make the thickness of the paper or paperboard uniform and to smoothen the surface of the paper or paperboard. In addition, the step of slitting and cutting the dried and calendered paper into a sheet or roll and packing the sheet or roll is finally performed, thereby producing industrial paper or corrugated board liner paper. In other words, in the slitting, cutting and packing step, the dried and calendered paper or paperboard is finally slit and cut into a sheet or roll according to the demand of consumers, and the sheet or roll is packed.

The above paper production method has been described with respect to the method for producing the industrial paper and corrugated board liner paper.

However, the paper production method according to the present invention is not limited only to said industrial paper and corrugated board liner paper. Thus, a method for producing wood-free paper and art paper will now be described in detail.

Specifically, the method for producing wood-free paper and art paper comprises a step of disintegrating the chemical bamboo pulp produced according to the above-described inventive method and a step of refining the disintegrated pulp.

Then, a step of blending the refined pulp with wood pulp (bleached chemical pulp of broadleaf trees) and a step of adding chemicals (sizing agent, filler, retention agent, dehydrating agent and other additives) to the blended pulp are carried out.

Also, the method comprises a step of screening the chemical-added pulp and a sheet forming step of making the screened pulp into a product (web) in the form of paper or paperboard. Also, the method comprises a pressing step of pressing the web obtained in the sheet forming step to remove water from the web, and a drying step of further removing water from the pressed web. Also, the method comprises a step of sizing the surface of the dried web, a step of drying the sized web, and a calendering step of making the thickness of the paper or paperboard uniform.

In addition, the method comprises a step of coating the paper or paperboard with a pigment, a step of drying the coated paper or paperboard, and a super-calendering step of imparting surface smoothness and gloss to the paper or paperboard.

Finally, the dried and super-calendered paper is slit and cut into a sheet or roll shape which is then packed, thus producing wood-free paper and art paper.

Most of the steps of this method, including the step of disintegrating the bleached chemical bamboo pulp and the step of refining the disintegrated pulp, are the same as those of the above-described method for producing the industrial papers and corrugated board liners.

However, this method is different in that it comprises the step of blending the refined pulp with wood pulp (board- leaved tree bleached chemical pulp, etc.), the step of sizing the surface of the dried web, the step of coating the paper, and the step of super-calendering the paper.

Thus, only the different steps of this method will now be described in detail.

Specifically, in the step of blending the refined pulp with wood pulp (bleached chemical pulp of broadleaf trees), the blending of the pulps is performed to adjust the various properties of paper to be produced, by blending the refined pulp with the bleached craft pulp, thermal mechanical pulp, chemical thermal mechanical pulp or bleached chemical thermal mechanical pulp of broadleaf trees at a suitable ratio according to the required properties of the paper.

In the production of wood-free paper such as writing and printing paper, coated base paper and the like, the bleached craft pulp of broadleaf trees is blended in an amount of about 50-80% to achieve the excellent smoothness and formation of paper so as to provide good printing quality. Also, in the production of newsprint paper and medium- quality paper, in order to provide sufficient strength properties, the bleached craft pulp of needle-leaf trees, the bleached chemical pulp of bamboos, white ledger or CPO (computer printout) deinked pulp is blended in an amount of 10-25%.

In the case of industrial paper, toilet paper and tissue paper, bamboo pulp can be used alone, and in some cases, it can be used in a mixture with wastepaper.

Also, in the step of sizing the surface of the dried web, the surface sizing is performed to control the impregnation of fluid into paper and improve the surface characteristics of paper so as to improve the surface strength and printing quality of the paper.

In this step, oxidized starch is usually used, but in some cases, the web can be treated with a coating pigment in a sizing press, such that the print quality of the paper can be further improved without a need for a coating process. Also, the method comprises the pigment coating step and the super-calendering step. The super-calendering step is performed to impart surface smoothness and gloss to the coated base paper.

Thus, using the inventive method for producing wood- free paper or art paper, the intermediate product pulp produced in the above-described method for producing the bleached chemical pulp for the production of tissue paper, wood-free paper, art paper or toilet paper is produced into wood-free paper or art paper as a final product. Furthermore, an embodiment of the method for producing printing and writing paper such as wood-free paper or coated base paper will now be described in further detail. Depending on the required print quality of paper, the bleached chemical bamboo pulp is blended with wood pulp such as the bleached chemical pulp or bleached chemical thermal mechanical pulp of broadleaf trees.

Also, papermaking chemicals such as 10-30% of filler (calcium carbonate, clay, talc, titanium dioxide, etc.), 0.1- 3% of a sizing agent (rosin emulsion, AKD or ASA) and/or a retention agent (cationic starch, PAM, bentonite, colloidal silica, organic microparticles, etc.) can be added to the pulp.

Also, to improve the surface strength and print quality of paper, the surface of paper is sized with oxidized starch. If necessary, the surface sizing can also be performed using a coating pigment.

The bleached chemical pulp of boardleaf trees is refined at an SEL of about 0.1-5.0 Ws/m, and the chemical bamboo pulp is refined at a weak SEL of about 0.01-2.5 Ws/m depending on the required properties of paper or is simply treated using a deflaker.

Meanwhile, according to the present invention, tissue paper and toilet paper can also be produced using the above- described method for producing the bleached chemical pulp. Thus, the steps of this method will now be described.

Specifically, this method comprises a step of disintegrating the bleached chemical bamboo pulp and a step of refining the disintegrated pulp.

Also, the method comprises a step of adding chemicals (sizing agent, retention agent, strengthening agent and other additives) to the refined pulp and a step of screening the chemical-added pulp.

Also, the method comprises a sheet forming step of making the screened pulp into a paper- or paperboard-like product, and a pressing step of pressing the web obtained in the sheet forming step to remove water from the web.

In addition, the method comprises a drying step of further removing water from the pressed web, and a final step of slitting and cutting the dried paper into a sheet or roll which is then packed, thus producing tissue paper.

The steps of said method for producing tissue paper and toilet paper have all been described in detail in the method for producing industrial papers and corrugated board liners and the method for producing wood-free paper and art paper, and thus will no longer be described.

Also, the present invention also provides a method for producing toilet paper using the bleached chemical bamboo pulp, and the method will now be described in detail.

Specifically, this method for producing toilet paper comprises a step of disintegrating the bleached chemical bamboo pulp produced according to the present invention, and a step of refining the disintegrated pulp.

Also, the method comprises a step of adding chemicals (sizing agent, retention agent, strengthening agent and other additives) to the refined pulp, and a step of screening the chemical-added pulp.

Also, the method comprises a sheet forming step of making the screened pulp into a paper or sheet product, and a pressing step of pressing the web obtained in the sheet forming step to remove water from the web.

In addition, the method comprises a drying step of further removing water from the pressed web, and a final step of slitting and cutting the dried paper into a sheet or roll which is then packed, thus producing toilet paper. The tissue paper or toilet paper is dried using a Yankee dryer and prepared to have low weight and thus low strength. For this reason, in order to impart the paper with the ability capable of resisting a force applied during the use thereof, a doctor blade attached to the end of the Yankee dryer is used to form invisible wrinkles on the tissue paper or toilet paper.

The steps of said method for producing toilet paper have all been described in detail in the method for producing industrial papers and corrugated board liners and the method for producing wood-free paper and art paper, and thus will no longer be described.

Furthermore, the present invention provides a method for producing newsprint paper or medium-quality paper using the refiner mechanical pulp of bamboos. Thus, this method will now be described in detail. First, in the method for producing newsprint paper or medium-quality paper using the refiner mechanical pulp of bamboos, a step of disintegrating the refiner mechanical pulp of bamboos is first carried out. Also, the method comprises a step of disintegrating and refining a strengthening pulp, and a step of blending the refined strengthening pulp with said refined refiner mechanical pulp.

Also, the method comprises a step of adding chemicals (sizing agent, filler, retention agent, strengthening agent and other additives) , and a sheet forming step of making the blended pulp into a paper or paperboard product.

Also, the method comprises a pressing step of pressing the web obtained in the sheet forming step to remove water from the web, and a drying step of further removing water from the pressed web.

In addition, the method comprises a step of sizing the surface of the dried web, a step of drying the sized web, and a step of slitting and cutting the dried paper into a sheet or roll which is then packed, thus producing newsprint paper or medium-quality paper.

To improve the print quality and the like of newsprint and medium-quality paper, the paper may also be coated with a coating pigment in a sizing press instead of performing the surface sizing.

The steps of said method for producing newsprint paper and medium-quality paper have all been described in detail in the method for producing industrial papers and corrugated board liners and the method for producing wood-free paper and art paper, and thus will no longer be described. Knowledge obtained through many experiments conduced by the applicant in order to obtain the optimal quality and productivity of papers is as follows.

In the production of toilet paper or thin wrapping paper, the bleached chemical pulp of bamboos is refined at an

SEL of 0.01-1.0 Ws/m, and if necessary, the sizing agent is used in an amount of 0-0.5%, and the strengthening agent is used in an amount of 0-0.5%.

If necessary, wrinkles are formed on the paper using a doctor blade in a Yankee dryer, or the paper is embossed after the drying step.

According to the present invention, using the antibacterial activity of the bleached chemical pulp of bamboo, various special purpose papers (non-woven fabric usable in various applications such as sanitary, clothing and hospital gowns and automobile inner materials, food or drug wrapping material, etc.) can be produced. [Mode for Invention]

Example 1 A Myanmar bamboo was split to a width of about 2 mm and then cut to a length of 15-25 mm. The cut material was screened through a 60-mesh screen to remove contaminants and small bamboo fragments, followed by washing.

400 g (on an oven-dry weight basis) of the washed bamboo was placed in a digester into which water was added.

Then, 16% (as Na₂O) active alkali and 0.1% anthraquinone were added thereto, and the ratio of the chemicals to the weight of the bamboo was adjusted to 4:1. Then, the bamboo chips were cooked in the digester at 170 ^°C for 120 minutes. The cooked pulp was washed and subjected to a five- stage bleaching of DED(EO)D, and the bleached pulp was refined with 400 ml of CSF, thus producing hand-made paper having a weight of 60 g/m². The properties of the resulting paper are shown in Table 1 below.

Table 1: Results of soda and soda-anthraquinon pulping tests

*Kappa number is used to indicate the amount of lignin remaining in the pulp produced in the digester, and is used as a standard for determining the amount of addition of chemicals in bleaching, and is calculated from the consumed amount of potassium permanganate through oxidation-reduction titration.

Example 2 The pretreatment of bamboo was performed in the same manner as in Example 1. Also, the amount of addition of chemical liquor in pulping was adjusted to 16%, 14% and 12%, and as an additive for promoting a reaction and protecting hemicellulose, 0.1% AQ was used. For the evaluation of the possibility of use as industrial paper, the pulp was not bleached. The washed pulp was refined with 400 ml of CSF, thus preparing hand-made paper having a weight of 80 g/m². The properties of the resulting paper are shown in Table 2 below.

Table 2: Test results for unbleached bamboo pulp

[industrial Applicability]

As described above, according to the present invention, the split and cut bamboo chips are pulped in the cooking process using the soda-anthraquinon process using anthraquinon as a catalyst. Thus, the present invention can have great effects on delignification, the improvement in pulp quality and the increase in pulp yield.

Also, according to the present invention, the bamboo chips are made thin in the raw material treatment process to facilitate the impregnation of liquid chemicals into the chips and the cooking of the chips. Also, papermaking pulp can be produced in milder conditions by previously eliminating the factors of causing the loss of chemicals and reducing the pulp quality. Furthermore, the soda-AQ process, in which anthraquinone is used as a catalyst in a cooking step, is applied for the pulping of bamboo, so that the present invention can have great effects on delignification, the improvement in pulp quality and the increase in pulp yield.

Also, an environmental problem such as the generation of dioxin can be solved by applying an ECF and TCF bleaching process, and it is possible to control the quality of paper depending on the properties of paper to be produced, by controlling the cooking and bleaching conditions.

In addition, through the above-described technology for producing high-quality paper making pulp, wood pulp produced from felled trees grown over dozens of years can be replaced with pulp produced from bamboos, which rapidly grow to a usable degree only within about five months. Thus, the present invention is expected to have a very great effect on greenhouse gas emission reduction, which should be considered for the preservation of global environment.

Claims

[CLAIMS] [Claim l]

A method for producing pulps from a bamboo, the method comprising: a first step of removing a leaf from a bamboo and splitting and cutting the leaf-removed bamboo to make bamboo chips; a second step of screening the cut bamboo chips to filter out small fragments or impurities from the bamboo chips and washing the chips the bamboo chips with water to remove contaminants from the bamboo chips; a third step of cooking the bamboo chips, in which the bamboo chips are introduced into a digester, the ratio of a chemical liquor consisting of water, alkali and anthraquinone to the weight of the bamboo chips is adjusted to 1:3.5-6.0 (bamboo: chemical liquor), and the bamboo chips are cooked at high temperature, thus softening and pulping the bamboo chips; a fourth step of cleaning the bamboo chips using a centrifugal cleaner so as to remove contaminants introduced together with the bamboo; a fifth step of screening the cooked pulp, in which contaminants are removed from the cooked pulp using a pressure screen, and an incompletely cooked portion of the bamboo is fed back into the digester; a sixth step of washing and thickening the screened pulp, in which a decker is used to wash the pulp, thus removing the chemical liquor, and to squeeze water so as to thicken the pulp; and a seventh step of using the thickened pulp to produce unbleached chemical and semi-chemical bamboo pulps for industrial papers or corrugated board liners.

[Claim 2] The method of Claim 1, wherein, in the third step of cooking the chips, the amount of alkali (as Na₂O) added to water is 10-30 % based on the oven-dry weight of the bamboo chips (i.e., mass excluding the content of moisture in the bamboo chips) , and the anthraquinon (AQ) is added in an amount of 0.01-2%.

[Claim 3]

A method for producing pulps from a bamboo, the method comprising: a first step of removing a leaf from a bamboo and splitting and cutting the leaf-removed bamboo to make bamboo chips; a second step of screening the cut bamboo chips to filter out small fragments or impurities from the bamboo chips and washing the chips the bamboo chips with water to remove contaminants from the bamboo chips; a third step of cooking the bamboo chips, in which the bamboo chips are introduced into a digester, the ratio of a chemical liquor consisting of water, alkali and anthraquinone to the weight of the bamboo chips is adjusted to 1:3.5-6.0 (bamboo: chemical liquor), and the bamboo chips are cooked at high temperature, thus softening and pulping the bamboo chips; a fourth step of cleaning the bamboo chips using a centrifugal cleaner so as to remove contaminants introduced together with the bamboo; a fifth step of screening the cooked pulp, in which contaminants are removed from the cooked pulp using a pressure screen, and an incompletely cooked portion of the bamboo is fed back into the digester; a sixth step of washing and thickening the screened pulp, in which a decker is used to wash the pulp, thus removing the chemical liquor, and to squeeze water so as to thicken the pulp; a seventh step of bleaching the pulp; and an eighth step of using the bleached pulp to produce bleached chemical pulp for the production of tissue paper, wood-free paper, art paper, non-woven fabric, special purpose paper or toilet paper.

[Claim 4] A method for producing pulps from a bamboo, the method comprising: a first step of removing a leaf from a bamboo and splitting and cutting the leaf-removed bamboo to make bamboo chips; a second step of screening the cut bamboo chips to filter out small fragments or impurities from the bamboo chips and washing the chips the bamboo chips with water to remove contaminants from the bamboo chips; a third step of primarily refining the washed bamboo chips, in which the washed bamboo chips are ground in a disc refiner; a fourth step of screening the refined bamboo chips, in which contaminants are removed from the ground bamboo chips using a pressure screen, and an incompletely defibrated portion of the chips is fed back into the disc refiner; a fifth step of secondarily refining the screened pulp fiber, in which the defibrated pulp fiber is further ground; a sixth step of screening the secondarily refined pulp, in which contaminants are removed from the refined pulp using a pressure screen, and an incompletely defibrated portion of the pulp fiber is fed back into the disc refiner; a seventh step of cleaning the screened pulp using a centrifugal cleaner so as to remove contaminants introduced together with the bamboo; and an eighth step of using the cleaned pulp to produce refiner mechanical pulp for the production of newsprint paper or medium-quality paper. [Claim 5]

The method of Claim 3, wherein the third step of bleaching the pulp is carried out using bleaching stages according to an ECF (elementary chlorine free) or TCF (total chlorine free) bleaching process. [Claim 6] ₍

The method of Claim 5, wherein the bleaching stages are selected from the group consisting of DED, DEDD, DEDP, DEZP, DEOP, DEOZ, PEOZ, DEDED, DED(EO)D, DEDOP and DEDZP. [Claim 7]

Natural bamboo pulp produced using the method of any one of Claims 1 to 6. [Claim 8]

The pulp of Claim 7, which is in the form of a sheet or roll. [Claim 9] The pulp of Claim 8, wherein the sheet pulp has a thickness of 0.1-3 nun. [Claim 10]

The pulp of Claim 8, wherein the roll pulp is obtained by winding a web having a thickness of 0.1-1.5 mm. [Claim 11]

A method for producing paper from bamboo pulp, the method comprising: a step of disintegrating the unbleached chemical and semi-chemical bamboo pulp produced according to the method of Claim 1; a step of refining the disintegrated pulp; a step of adding chemicals (sizing agent, retention agent, strengthening agent and other additives) to the refined pulp; a step of screening the chemical-added pulp; a sheet forming step of making the screened pulp into a product (web) in the form of paper or paperboard; a pressing step of pressing the web obtained in the sheet forming step to remove water from the web; a drying step of further drying water from the pressed web;

^"a calendering step of making the thickness of the paper or paperboard uniform; and a step of slitting and cutting the dried paper into a sheet or roll and packing the sheet or roll, thereby producing industrial paper or liner paper for corrugated boards. [Claim 12] A method for producing paper from bamboo pulp, the method comprising: a step of disintegrating the bleached chemical bamboo pulp produced according to the method of Claim 3; a step of refining the disintegrated pulp; a step of blending the refined pulp with wood pulp (bleached chemical pulp of broadleaf trees) ; a step of adding chemicals (sizing agent, filler, retention agent, dehydrating agent and other additives) to the blended pulp; a step of screening the pulp having the chemicals added thereto; a sheet forming step of making the screened pulp into a product (web) in the form of paper or paperboard; a pressing step of pressing the web obtained in the sheet forming step to remove water from the web; a drying step of further removing water from the pressed web; a step of sizing the surface of the dried web; a step of drying the sized web; a calendering step of making the thickness of the paper or paperboard uniform; a step of coating the calendered paper or paperboard with a pigment; a step of drying the coated paper or paperboard; a super-calendering step of imparting smoothness and gloss to the surface of the dried paper or paperboard; and a step of slitting and cutting the calendered paper into a sheet or roll and packing the sheet or roll, thereby producing wood-free paper and art paper. [Claim 13]

A method for producing paper from bamboo pulp, the method comprising: a step of disintegrating the bleached chemical bamboo pulp produced according to the method of Claim 3; a step of refining the disintegrated pulp; a step of adding chemicals (sizing agent, retention agent and other additives) to the blended pulp; a step of screening the pulp having the chemicals added thereto; a sheet forming step of making the screened pulp into a product (web) in the form of paper or paperboard; a pressing step of pressing the web obtained in the sheet forming step to remove water from the web; _; a drying step of further removing water from the pressed web; and a step of slitting and cutting the dried paper into a sheet or roll and packing the sheet or roll, thereby producing tissue paper. [Claim 14]

A method for producing paper from bamboo pulp, the method comprising: a step of disintegrating the bleached chemical bamboo pulp produced according to the method of Claim 3; a step of refining the disintegrated pulp; a step of adding chemicals (sizing agent, retention agent and other additives) to the blended pulp; a step of screening the pulp having the chemicals added thereto; a sheet forming step of making the screened pulp into a product (web) in the form of paper or paperboard; slitting and cutting the calendered paper into a sheet or roll and packing the sheet or roll, thereby producing toilet paper. [Claim 15]

A method for producing paper from bamboo pulp, the method comprises: a step of disintegrating the refiner mechanical pulp produced according to the method of Claim 4; a step of disintegrating and refining a reinforcing pulp; a step of blending the disintegrated refiner mechanical pulp with the refined reinforcing pulp; a step of adding chemicals (sizing agent, filler, retention agent, strengthening agent and other additives) to the blended pulp; a sheet forming step of making the blended pulp into a product (web) in the form of paper or paperboard; a pressing step of pressing the web obtained in the sheet forming step to remove water from the web; a drying step of further removing water from the pressed web; and a step of sizing the surface of the dried web; a step of drying the sized web; and slitting and cutting the dried paper into a sheet or roll and packing the sheet or roll, thereby producing newsprint paper or medium-quality paper.