Branch type dry strength agent and preparation method thereof

Abstract

The invention discloses a branch type dry strength agent and a preparation method thereof. The preparation method comprises the following steps of: firstly, mixing acrylamide, negative ion monomers, positive ion monomers, crosslinking agent monomers, a photoinitiator, water and other functional monomers to obtain solution A; secondly, mixing a chain transfer agent and water to obtain solution B; thirdly, polymerizing 40%-60% of the solution A and 20%-40% of the solution B by ultraviolet ray irradiation; fourthly, adding 20%-30% of the solution A and 20%-30% of the solution B into the mixed solution in the third step to be subjected to polymerization by ultraviolet ray irradiation; fifthly, adding the residual solution A and the residual solution B into the mixed solution in the fourth step to be subjected to polymerization by ultraviolet ray irradiation until the viscosity of the solution meets requirements; and sixthly, adjusting the pH and solid content of weight of the mixed solution in the fifth step, and adding free radical catcher into the mixed solution to obtain the branch type dry strength agent. According to the branch type dry strength agent and the preparation method, the operation is simple, the viscosity is easy to control, the dispersibility of the branch type dry strength agent in water is good, the properties of ring crush, fold resistance, breaking resistance, tension resistance, internal bonding strength and the like of paper can be improved.

Description

technical field [0001] The invention relates to a dry strength agent for papermaking and a preparation process thereof. Background technique [0002] Dry strength agent is an important class of chemicals in the paper industry to increase the strength of paper. It is usually used to compensate for the decrease in paper strength caused by adding fillers or low-grade fibers (such as recycled fibers). Many water-soluble polymers capable of forming hydrogen bonds with fibers can be used as dry strength agents. [0003] Commonly used dry strength agents include natural polymers such as starch and its modified products (cationic starch, anionic starch, cross-linked starch, etc.), synthetic polymers such as polyacrylamide, polyvinyl alcohol, etc., and other water-soluble natural products. agents (such as guar gum and its derivatives, etc.). In most cases, only adding 0.1%~0.75% of such substances by mass fraction can achieve effective dry strength effect. [0004] In recent years...

AI Technical Summary

Problems solved by technology

However, there are some defects in these two methods: the method of adding raw materials at one time, due to the high concentration of reactants, is easy to produce implosion polymerization and then produces gelation effect; Polymers are formed at low concentrations, and then the added monomers continue to reflect in the solution of these polymers, so that the concentration of monomers can be kept at a low level to prevent implosion, but when the polymer solution reaches a certain viscosity, add later The monomers and initiators in the system cannot be stirred evenly into the system in time, resulting in excessive local concentration, resulting in local detonation and gelation, which is also a problem that needs to be solved

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