KR20140017931A - Method for preparing of puip from bast fiber - Google Patents

Abstract

The present invention relates to a method for wood pulps proper for the Han-ji (Korean traditional paper) which obtains a white skin by removing wood materials and a black skin from bast fibers and neutralizes and bleaches the white skin with caustic soda. Pulps can be manufactured within two hours a small and simple device is utilized so that the present invention can reduce time and manpower required for manufacturing pulps. The pulps are damaged less than existing pulps obtained from bast fibers so that the present invention can manufacture products having an excellent quality. [Reference numerals] (AA) Feed material; (BB) Heating, Pressurizing; (CC) Cooking; (DD) Washing; (EE) Bleaching; (FF) Washing; (GG) Drying

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for preparing pulp from bast fiber,

The present invention relates to a method for producing pulp from bast fibers, and more particularly to a method for producing pulp from bast fibers, To a method for producing a pulp suitable for the manufacture of Korean paper.

 The bast fiber is a soft fiber obtained from the stem of a flowering plant with sunflower, roses and most trees and flax. . Cells of bast fibers are 1-2 mm thick and 0.01-0.02 mm in thickness. Commercial bast fibers include flax, hemp, jute, sheep, moth and mulberry.

       Typically, when pulp is manufactured, the chemical is added to pulp raw materials such as wood, and then it is subjected to a steam process, which is a process of boiling in a kiln. The wood-based bast fiber such as mulberry, mountain mulberry, mulberry mulberry and mulberry is called water Sheath-scabbled white skin and herbaceous scouring bast fibers such as hemp, flax, and jima are used. Caustic soda (NaOH) or soda ash is used as a chemical for pulping, and pulp can be pulped only if it boils for 3 ~ 5 hours regardless of medicines. In addition, since pulp manufacturing depends on manual operation of most processes, it is impossible to automate the pulp manufacturing process, and labor, time, and cost are considerably consumed.

       On the other hand, in order to pulp the dried skins from the wood as it is, it is necessary to boil them for ca. 4 to 4 hours using caustic soda. In this case, the pulp is black in color and does not bleach But also the yield of the pulp is lowered due to the damage of the fibers caused by the alkali at the pulping and the bleaching agent at the time of bleaching, and the quality of the pulp is lowered, making it difficult to produce high quality pulp having excellent storability.

       As a prior art on a method for producing pulp from bast fiber, Patent Document 10-2011-12532 discloses a method for producing a bast / bast fiber, comprising: (S1) immersing bast fibers in an ammonium hydroxide solution; Pulping (S2) after the step (S1); After the step (S2), a chemical liquid washing and a tea washing step (S3) are performed; (S4) a step of pulping the pulp, wherein the pulp is pulverized, and the pulp is pulverized. However, the pulp is pulverized at a room temperature of 10 to 25 ℃ for 12 ~ 48 hours. Therefore, it takes a lot of time and requires a lot of labor force.

Therefore, there is a need to develop a technique that shortens the time required for the pulping of bast fiber to minimize time and manpower.

Disclosure of the Invention The present invention has been conceived in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method for producing a pulp suitable for the manufacture of Korean paper by removing the woody part and black skin from wood- To be provided.

 The present invention relates to a method for producing a pulp from bast fibers, comprising the steps of: 1) mixing the bast fibers, which are bast fibers and bast fibers, from which the bast fibers have been removed, in a ratio of 1: 7 to 10 parts by weight of caustic soda, Lt; / RTI > for 90 minutes to 30 minutes; 2) washing the unbleached bast fibers obtained in the above step of washing with water; 3) adding the hydrogen peroxide to the bast fibers having the blackness and the impurities removed in the washing step at a ratio of 1:19 parts by weight and bleaching the mixture at a temperature of 45 ° C for 30 minutes; 4) washing the bast fibers obtained in the bleaching step with water and drying the bast fibers;

Further, the present invention provides a method for producing pulp from bast fibers, wherein the caustic soda is an aqueous solution of 30% to 35%.

       The present invention also provides a method for producing pulp from bast fibers characterized in that the hydrogen peroxide is a 1.5% aqueous solution.

Finally, the present invention provides a bast fiber pulp produced by the above production method.

The present invention having the above-described configuration can be expected to have the following effects.

       First, the pulp can be manufactured within a short time of 2 hours by using a small-sized apparatus having a simple structure, shortening the time required for manufacturing and greatly reducing labor force,

Second, since the damage of the fiber is lower than that of the pulp obtained from the conventional bast fiber, a high-quality product can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a process for producing pulp from bast fibers according to the invention
2 is a SEM photograph of the pulp produced from the bast fiber according to the present invention
Fig. 3 is a SEM photograph of a Thai infective fiber pulp

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

       As described above, the method for producing the pulp from the bast fibers according to the present invention

1) mixing the white fiber, which is the bast fiber and the white fiber, with the caustic soda at a ratio of 1: 7 to 10 parts by weight with caustic soda, and heating it at 1 to 8 atm and 100 to 160 ° C for 90 to 30 minutes;

2) washing the unbleached bast fibers obtained in the above step of washing with water;

3) adding the hydrogen peroxide to the bast fibers having the blackness and the impurities removed in the washing step at a ratio of 1:19 parts by weight and bleaching the mixture at a temperature of 45 ° C for 30 minutes;

4) washing the bast fibers obtained in the bleaching step with water and drying.

     First, the woody part and the white fiber, which is the bast fiber which has been stripped of snowflake, are mixed with caustic soda at a ratio of 1: 7 to 10 parts by weight, wherein the caustic soda is mixed with a digesting liquid (Vaporized liquid), and the concentration thereof is preferably 30 to 35% by weight aqueous solution of caustic soda. If the concentration is less than 30% by weight, lignin is not easily removed, and it is difficult to complete the digestion. If the concentration exceeds 35% by weight, the remaining amount of lignin is about 1%, which is not lowered further.

     The mixing ratio of white wax to caustic soda was 1:20 or more in the conventional method, but the boiling time is long as the content of caustic soda is too low. In the present invention, the ratio of 1: 7 to 10 parts by weight is most suitable. When the amount is less than 7 parts by weight, the peeled bast fiber is not sufficiently immersed in caustic soda, The removal rate of lignin due to cooking does not increase any more but the cost of caustic soda is increased only.

     It is preferable to maintain the pressure at 1 to 8 atmospheres during the steaming, and when the pressure is less than 1 atmospheres, the pressure is not applied to the steaming apparatus, so that the steaming time takes more than 2 hours. When the pressure exceeds 8 atmospheres, There is a disadvantage in that the cost is increased.

     In addition, the temperature at the time of steaming is preferably in the range of 100 to 160 ° C. When the temperature is less than 100 ° C, the steaming time is prolonged because the steaming is not sufficiently performed. If the temperature exceeds 160 ° C, the steaming time is shortened, Lt; / RTI >

     The digestion time is preferably from 90 minutes to 30 minutes. If the digestion time exceeds 90 minutes, the lignin removal rate is not increased any more but the energy cost is increased. If the digestion time is less than 30 minutes, the digestion is not sufficiently performed, A problem occurs.

     Since the unbleached bast fiber obtained after the completion of the digestion in the above-mentioned digestion step contains impurities which are nonfibrous eluates such as black liquor and lignin, washing with water as an operation to remove it is required.

     On the other hand, in the washing step, the bast / leaf fibers in which the blackening and the impurities are removed are deeply colored and are not suitable for producing paper immediately. Therefore, the bleached bast fiber must be bleached using hydrogen peroxide as a bleaching agent. At this time, the concentration of hydrogen peroxide was better than that of the concentration of 3% at the concentration of 1.5%, since the Kappa value, which is the index of the lignin content and the flouring index in the pulp, The ratio is preferably 1: 19 parts by weight.

     In addition, the bleaching temperature was better than 45 ℃ when Kappa value was lower than 60 ℃. Kappa value was similar to bleaching time when the bleaching time was 30 min. , And whiteness of 45 ° C was the best, because the degree of whiteness tends to deteriorate due to deterioration of cellulose as temperature increases.

     Since the bleached bast fiber obtained after completing the bleaching step contains a large amount of bleaching agent and washing water, it must be washed several times with water in order to remove it, and after that, the bleached bast fiber is sufficiently dried, Fiber pulp can be easily produced.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments and experimental examples.

     1 kg prepared by cutting woody part and mulberry bark of mulberry tree, cut into a length of about 1 m, was put into the tank, and then 10 liters of 30% caustic soda aqueous solution was charged into the tank and sealed in the tank . Then, the internal temperature of the steaming tank was maintained at 160 캜 and the pressure was maintained at 8 atm for 30 minutes.

After completion of the digestion, washing water was supplied to the inside of the pressure tank, and the digested solution was washed several times to obtain unbleached bast fiber. Then, 15 liters of a 1.5% hydrogen peroxide aqueous solution was added thereto as a bleaching agent, Bleached bast fibers were washed with water several times and then dried to obtain 0.7 kg of bleached bast fiber pulp.

<Comparative Example>

     Bleached bast fiber pulp (Standard grade) manufactured from Thai mackerel was used as a comparative example.

       The bast fiber pulp obtained in the above-mentioned Examples and Comparative Examples will be specifically explained by examining the results of the following test items.

<Experimental Example 1> SEM analysis

The pulp obtained in Examples and Comparative Examples was photographed at a magnification of 1000 at a scanning electron microscope (SEM), as shown in [Fig. 2] and [Fig. 3]. From the photographs, it can be seen that the surface of the pulp according to the embodiment (Fig. 2) is smoother than the product of the comparative example (Fig. 3), and the pulp is less damaged, which is an excellent product.

&Lt; Experimental Example 2 >

The pulp obtained in the examples and the comparative examples was beating and ground to obtain a product having a thickness of 0.5 mm and a basis weight of 60 g / m 2. The following tensile strength and tensile index were measured for the obtained paper, 1].

Tensile strength (N / mm) Tensile Index (Nm / g) Remarks  Example 1.285 21.062 Test method KS M ISO 1924-3  Comparative Example 0.575 9.057

     [Table 1] From the results of Table 1, it can be seen that the paper according to the present invention has the same thickness and basis weight as the comparative example in comparison with the comparative example of the paper obtained from the Thai infant fiber pulp, but the tensile strength and tensile index are high, It can be seen that this product is a superior product because of its strong binding force.

While the present invention has been particularly shown and described with reference to embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments.

Claims (4)

A method of making a pulp from a bast fiber,
1) The wood fiber and the white fiber, which is the bast fiber having the black skin removed, are mixed with caustic soda at a ratio of 1: 7 to 10 parts by weight
Mixing and agitating at a pressure of 1 to 8 atm and a temperature of 100 to 160 DEG C for 90 to 30 minutes;
2) washing the unbleached bast fibers obtained in the above step of washing with water;
3) adding the hydrogen peroxide to the bast fibers having the blackness and the impurities removed in the washing step at a ratio of 1:19 parts by weight and bleaching the mixture at a temperature of 45 ° C for 30 minutes;
4) washing the bast fibers obtained in the bleaching step with water and drying the bast fibers;
The method according to claim 1,
Wherein said caustic soda is a 30% to 35% aqueous solution.
3. The method of claim 2,
Wherein the hydrogen peroxide is a 1.5% aqueous solution.
A bast fiber pulp produced by the method according to any one of claims 1 to 3.

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