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Chloride-free bleaching method for bark pulp used for drawing paper and application

A technique for calligraphy and painting paper, totally chlorine-free, applied in pulp bleaching, post-treatment of cellulose pulp, papermaking, etc., can solve the problems of high cost of enzyme pretreatment, large amount of xylanase and high cost of bleaching, and improve the reaction activity. , easy to take off, easy to bleach effect

Active Publication Date: 2019-01-11
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The application number is 201510138354.7, the name is "a method for reducing AOX generation by using xylanase to assist chlorine dioxide bleaching of pulp", the application number is 201510615793.2, and the name is "a method for biological enzyme pretreatment to assist bamboo pulp ECF bleaching, These two Chinese patents use xylanase for pretreatment, but the amount of xylanase is large and the cost of enzyme pretreatment is high
[0007] Based on the current situation of high cost, long cycle, heavy pollution and poor paper performance of bark pulp bleaching for painting and calligraphy paper, it is necessary to find a low-cost, high-efficiency and environmentally friendly bleaching method for leather painting and calligraphy. paper production

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0047] Raw material: self-made unbleached sandalwood bark pulp using alkaline pulping (references: Wang Dehan. Research on the melting of resin in the process of alkaline pulping of structure bark. Guangdong Papermaking. 1996:24-27.), and its specific preparation method is : Alkali pulping, total alkali consumption 20% (calculated as NaOH), degree of sulfidation 15%, anthraquinone 0.05%, liquid ratio 1:4, heating time 2h, holding time 3h, maximum temperature 140°C. The whiteness of unbleached sandalwood pulp is 34.9% ISO, and the kappa number is 14.3.

[0048] The bleaching process is as follows:

[0049] (1) Two-stage alkali pretreatment:

[0050]1. add water to adjust the slurry concentration of unbleached bark pulp (unbleached sandalwood pulp) to be 10%, then add milk of lime and sodium pyrophosphate to react; wherein, in absolute dry pulp, the milk of lime consumption is 12wt%, coke The dosage of sodium phosphate is 0.5wt%; the treatment temperature is 60°C, and the trea...

Embodiment 2

[0055] Raw materials: self-made unbleached sandalwood pulp by alkaline pulping, the whiteness of the unbleached sandalwood pulp is 34.9% ISO, and the kappa number is 14.3.

[0056] The bleaching process is as follows:

[0057] (1) Two-stage alkali pretreatment:

[0058] 1. add water to adjust the slurry concentration of unbleached bark pulp (unbleached sandalwood pulp) to be 12%, then add milk of lime and sodium pyrophosphate to react; wherein, in absolute dry pulp, the milk of lime consumption is 14wt%, coke The dosage of sodium phosphate is 0.7wt%; the treatment temperature is 65°C, and the treatment time is 36h. After the reaction is completed, the milk of lime is filtered, concentrated and reused, and the washed slurry is stored for future use.

[0059] ②Take the slurry prepared above, adjust the concentration of the slurry to 13% by using 2% sodium hydroxide solution, the treatment temperature is 65°C, and the treatment time is 3 hours. After the treatment is complete,...

Embodiment 3

[0063] Raw materials: self-made unbleached sandalwood pulp by alkaline pulping, the whiteness of the unbleached sandalwood pulp is 34.9% ISO, and the kappa number is 14.3.

[0064] The bleaching process is as follows:

[0065] (1) Two-stage alkali pretreatment:

[0066] 1. add water to adjust the slurry concentration of unbleached bark pulp (unbleached sandalwood pulp) to be 15%, then add milk of lime and sodium pyrophosphate to react; wherein, in absolute dry pulp, the milk of lime consumption is 15wt%, and The dosage of sodium phosphate is 1.0wt%, the treatment temperature is 70°C, and the treatment time is 48h. After the reaction is completed, the milk of lime is filtered, concentrated and reused, and the washed slurry is stored for future use.

[0067] ②Take the slurry prepared above, adjust the concentration of the slurry to 15% by using 2% sodium hydroxide solution, the treatment temperature is 80°C, and the treatment time is 4 hours. After the treatment is complete, ...

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Abstract

The invention discloses a chloride-free bleaching method for bark pulp used for drawing paper and an application. The chloride-free bleaching method comprises the following steps: (1) two-stage alkalipretreatment: 1) adding lime milk and sodium pyrophosphate into unbleached bark pulp, reacting and filtering, thereby acquiring a pulp A, and 2) using a sodium hydroxide solution for regulating the pulp A till the mass concentration of the pulp A is 10-15%, stirring and reacting, washing and drying, thereby acquiring a pulp B; (2) xylanase pretreatment: regulating the mass concentration of the pulp B to 10-15%, and then regulating pH to 4-6, adding xylanase and reacting, thereby acquiring a pulp C; (3) hydrogen peroxide bleaching: regulating the mass concentration of the pulp C to 10-15%, andthen regulating pH to 11, adding EDTA, H2O2 and O2 for bleaching, and washing. The method disclosed by the invention can solve the problems of large time consumption, severe pollution, and inferior pulping ink moistening property of bark pulp bleaching and is suitable for bleaching various bark pulps.

Description

technical field [0001] The invention belongs to the technical field of papermaking, and in particular relates to a method and application of completely chlorine-free bleaching of bark pulp for calligraphy and painting paper. Background technique [0002] As a high-grade cultural paper in my country, calligraphy and painting paper has played a profound role in promoting the development of traditional culture in the long history of more than 1,000 years. High-end calligraphy and painting paper sought after by literati and poets. [0003] At present, the fiber raw materials commonly used for leather calligraphy and painting paper are mainly sandalwood bark, mulberry bark, and mulberry bark. The traditional leather pulping process mainly includes the steps of fur, skin embryo, green hide, burnt skin, burnt skin pulping and other steps. The total time-consuming is about one and a half years, and the processing time for fiber bleaching is about one year. The traditional leather b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21C9/10D21C9/16
CPCD21C9/1005D21C9/163
Inventor 王阳杨仁党刘旭
Owner SOUTH CHINA UNIV OF TECH
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