Preparation method of Xuan paper wingceltis bark pulp

Abstract

The invention belongs to the field of Chinese art paper, and particularly relates to a preparation method of Chinese art paper wingceltis bark pulp, which is characterized in that in the preparation process of the wingceltis bark pulp, pulping is performed firstly, and then bleaching is performed. According to the scheme, black skin obtained after wingceltis skin is cooked is beaten into pulp and then screened, in the bleaching process after the treated black skin is cut off and defibered, the contact specific surface area of black skin fibers and bleaching liquid is increased, the bleaching liquid can fully permeate into fiber tissues, the whiteness of the bleached pulp is uniform, the phenomena of yellow skin and half-raw skin do not exist, and the quality of the pulp is improved. The bleaching quality of the pulp is enhanced; the beating degree is controlled in the beating link, so that the fiber length of the bleached wingceltis bark pulp can be effectively improved, the strength of a Chinese art paper product is greatly improved, and the product quality is improved.

Description

Technical Field

[0001] The invention belongs to the field of rice paper, and in particular relates to a method for preparing sandalwood pulp for rice paper. Background Art

[0002] The raw materials for making Xuan paper include Chinese ash bark and paddy rice straw. The process of making Chinese ash bark pulp is generally to boil it first, then bleach it and then beat it. This process has been continued to this day. The steaming of sandalwood bark is to put the whole sandalwood bark into the pot for boiling. Since the steamed sandalwood bark is a whole piece, it is difficult for the bleaching liquid to penetrate into the fibers in the bark during the bleaching process. The bleached bark often has sandwiched bark (the bark is not bleached thoroughly). When the whole bark is bleached, the bark is not turned evenly in the bleaching tank, resulting in some bark being bleached and some not being bleached well. In other words, during the bleaching process, the bark has yellow skin and other phenomena. Moreover, when the whole bark is steamed, it is inevitable that there will be skin sticks mixed in the bark, which seriously affects the bleaching quality of the sandalwood bark. Summary of the invention

[0003] The purpose of the invention is to provide a method for preparing sandalwood pulp for rice paper, so as to solve the problems of yellow skin, raw skin or over-bleaching in the preparation process of sandalwood pulp.

[0004] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing sandalwood pulp for rice paper, characterized in that the sandalwood pulp is first pulped and then bleached during the preparation process.

[0005] In the above scheme, the black skin of sandalwood after steaming is first beaten into pulp and then screened. After the processed black skin is cut and loosened, during the bleaching process, the black skin fiber increases the contact specific surface area with the bleaching liquid, and the bleaching liquid can fully penetrate into the fiber tissue. The bleached pulp has uniform whiteness, without yellow skin and raw skin, thereby enhancing the bleaching quality of the pulp. Controlling the beating degree in the pulping stage can effectively increase the fiber length of the sandalwood pulp after bleaching, greatly improve the strength of the rice paper product, and improve the product quality.

[0006] Specifically, the pulp after beating is diluted with water and screened through a flat screen, and then bleached and washed. The screen hole of the flat screen is 0.5 mm. This screening operation is to dilute the beaten pulp with water and screen it through a flat screen to remove larger coarse fiber bundles and leather sticks and other debris in the pulp.

[0007] After beating, the pulp is screened by a flat screen and then shaken, bleached and washed. The shaking process is to place the pulp in a rotating horizontal cylindrical screen, and continuously spray water on the outside of the cylindrical screen to wash the pulp. The cylindrical screen is a 60-80 mesh screen. The shaking process is to remove fine fibers and thin-walled cells in the pulp to avoid affecting the strength of the paper after papermaking; on the other hand, it is also to wash away the soluble macromolecules in the sandalwood fiber to improve the water absorption and ink wetting properties of the rice paper.

[0008] The bleaching liquid is hydrogen peroxide with a mass concentration of 10-15%. This step is essentially the same as the bleaching liquid used in the bleaching process of the original sandalwood pulp production process.

[0009] Generally speaking, sandalwood bark pulp is obtained after being processed by soaking, steaming, removing black liquor, beating, screening, shaking and rinsing. After the sandalwood bark pulp is mixed with straw pulp, it can enter the papermaking stage.

[0010] The traditional production process of sandalwood bark pulp is soaking, boiling, removing the second black liquor, bleaching, washing, beating, shaking the bark, and pulping. After boiling, the sandalwood bark is first bleached and then pulped. Due to the different sizes and uneven thickness of sandalwood bark, it is inevitable that the bark will be yellow or raw. In particular, the damage of the bleaching liquid to the sandalwood bark fiber during the bleaching process seriously affects the average length of the fiber after pulping.

[0011] The sandalwood bark pulp production process of the present invention breaks the shackles of traditional processes that have been passed down for many years and have mature production processes. It boldly moves the pulping step to the front to complete, and the steps of flat screening, shaking the skin and the like are all completed in the pulp state, which not only improves the removal rate and removal efficiency of the soluble components in the sandalwood bark, but also the texture of the sandalwood bark in the pulp state is uniform, which reduces the difficulty of bleaching, and completely prevents the occurrence of yellow skin, raw skin, over-bleaching and the like, greatly improves the quality of the sandalwood bark pulp, and thus improves the quality of rice paper products.

[0012] More importantly, after the beating step is placed in front, the inventor has found through a lot of practice that the phenomenon that the length of sandalwood bark pulp cannot be increased due to the damage of the bleaching liquid to the sandalwood bark fiber has also disappeared. This is because in the traditional process, the sandalwood bark is first bleached, and the bleaching liquid damages the sandalwood bark fiber. The physical damage to the fiber in the subsequent beating process makes it difficult for the fiber to maintain a longer length. Therefore, the average fiber length in the sandalwood bark pulp is generally 2.20-2.26 mm, and it is difficult to exceed 2.30 mm. After adopting the scheme of the present application, the sandalwood bark is first subjected to the beating process. The physical damage to the sandalwood bark only makes the sandalwood bark fiber loose and dispersed, and does not destroy its essence. Although the subsequent bleaching operation process damages the sandalwood bark fiber, on the one hand, the fine fibers have been filtered out in the shaking bark link, and on the other hand, after bleaching and washing, it directly enters the pulping and paper scooping link, which does not affect the length of the sandalwood bark fiber. Therefore, the technical scheme of the present invention can effectively increase the average fiber length in the sandalwood bark pulp, thereby improving the strength of the rice paper product. DETAILED DESCRIPTION

[0013] The technical solution of the present invention is further described in detail below in conjunction with embodiments.

[0014] Example 1

[0015] The same batch (first batch) of sandalwood bark is made into sandalwood bark pulp by the following two methods:

[0016] 1. The sandalwood bark is prepared by the traditional process of soaking the bark → steaming → removing the secondary black liquor → bleaching → washing → beating → shaking the bark → pulping to obtain the first pulp;

[0017] 2. The sandalwood bark pulp is prepared by the process of soaking the bark → steaming → removing the secondary black liquor → beating → flat screening → shaking the bark → rinsing → pulping to obtain the second pulp.

[0018] The bleaching liquid of the above two schemes is 12% hydrogen peroxide, and the equipment, specifications and parameters used in other links are the same: the shaking skin uses a 60-mesh cylindrical screen, and the flat screening uses a bar screen with a pore size of 2-3mm. The various parameters and test data of the above-obtained slurry 1 and slurry 2 are recorded in Table 1.

[0019] Table 1 Data records of the first batch of sandalwood pulp made from sandalwood

[0020]

[0021] Example 2

[0022] Different batches of sandalwood bark (the second batch and the third batch) were used to prepare sandalwood bark pulps using the same two schemes as in Example 1. The sandalwood bark pulps obtained from the second batch of sandalwood bark were recorded as pulp three (bleaching first and then pulping) and pulp four (pulping first and then bleaching), and the sandalwood bark pulps obtained from the third batch of sandalwood bark were recorded as pulp five (bleaching first and then pulping) and pulp six (pulping first and then bleaching). Various parameters and test data are recorded in Tables 2 and 3.

[0023] Table 2 Data records of the second batch of sandalwood bark pulp

[0024]

[0025] Table 3 Data records of the third batch of sandalwood bark pulp

[0026]

[0027] From the above data, it can be seen that the use of the technical solution of the present invention to prepare sandalwood bark pulp not only completely avoids the phenomenon of yellow skin, raw skin and over-bleaching of sandalwood bark, but also saves the amount of bleaching liquid, and increases the average length of fibers in sandalwood bark pulp, thereby greatly improving the physical strength and overall quality of rice paper products.

Claims

1. A method for preparing rice paper sandalwood pulp, characterized in that: In the process of making sandalwood pulp, the pulping is done first and then bleaching.

2. The method for making rice paper sandalwood pulp according to claim 1, characterized in that: The pulp after beating is diluted with water and screened through a flat screen, followed by bleaching and washing. The mesh size of the flat screen is 0.5 mm.

3. The method for making rice paper sandalwood pulp according to claim 1 or 2, characterized in that: The pulp after beating is screened by a flat screen and then shaken, bleached and washed. The shaking is that the pulp is placed in a rotating horizontal cylindrical screen, and the outside of the cylindrical screen is continuously sprayed with water to wash the pulp. The cylindrical screen is a 60-80 mesh screen.

4. The method for making rice paper sandalwood pulp according to claim 1, characterized in that: The bleaching liquid is hydrogen peroxide with a mass concentration of 10-15%.

5. The method for making rice paper sandalwood pulp according to claim 1, characterized in that: The sandalwood bark is processed in sequence of soaking, boiling, removing the secondary black liquor, beating, screening, shaking and rinsing to obtain the sandalwood bark pulp.

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