New technique for improving paper strength by joint gelatinization of starch and pulp

Abstract

The invention belongs to the technical field of paper strengthening, in particular to a method using starch as a paper dry strengthen agent. The method comprises the following steps: uniformly mixing starch accounting for 0.5-25% of oven dry mass of pulp with pulp, carrying out extrusion and concentration, heating for 8-150min at 70-100 DEG C to gelatinize starch, carrying out defibering and dispersion on the heated pulp, and manufacturing paper with pulp. The invention has simple process, low production cost and less pollution, improves the strength of paper by 30-110%, has above 80% of starch retention ratio, and can improve the retention ratios of fillers and fiber fines.

Description

technical field [0001] The invention relates to a process method for papermaking reinforcement, and belongs to the technical field of pulping and papermaking technology. Background technique [0002] The traditional methods of paper strengthening are physical methods of beating or chemical methods of adding strengthening additives. Considering the deficiency of beating to improve the strength, various dry strength agents are usually used to improve the strength of paper. A class of fine chemicals used to enhance the dry strength of paper and board is called dry strength agents. There are four main types of dry strength agents: (1) Synthetic polymers. Such as polyacrylamide, polyvinyl alcohol, urea-formaldehyde resin and melamine resin. (2) Modified starch. Such as cationic starch, anionic starch, amphoteric starch, nonionic starch, etc. (3) Cellulose, chitin derivatives and plant gums. Such as carboxymethyl cellulose, chitin, chitosan and so on. (4) Resin barrier cont...

AI Technical Summary

Problems solved by technology

At the same time, after the waste paper pulp is reused many times, the performance of the fiber itself will be affected, and the fiber will become finer and harder, which is not conducive to beating treatment, and the strength of the paper is also very poor.

During the application process, there will be low surface strength and the status quo of shedding hair and powder

[0004] (2) The cost of the existing dry strength agent is relatively high, such as cationic starch and cationic polyacrylamide, the cost is relatively high. If raw starch, oxidized starch and other relatively cheap materials can be used as the dry strength agent, the cost can be greatly saved

[0005] (3) The limitation of the retention rate when the starch is used in a high amount

For fiber raw materials with poor quality, the strength of the produced paper is even worse

[0006] (4) Limitations of starch-enhanced paper strength

However, the decline in fiber quality after repeated use is bound to have a great impact on the strength of the paper

[0007] (5) Existing dry strength agents such as polyacrylamide (PAM), cationic starch, anionic starch, and amphoteric starch are easily affected by the system

The principle of the traditional method of dry strength agent reinforced paper is to use the ionic characteristics of the chemical itself to adsorb the fiber, which is greatly disturbed by the system, and the anion garbage affects the retention effect of the additive, and the charged ions in the system attract each other. It is easy to form flocculation, so the efficiency of the dry strength agent is affected to a certain extent. To eliminate these effects, it is necessary to increase the cost

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