Preparing method for AKD (Alkyl Ketene Dimer) latex

Abstract

The invention discloses a preparing method for AKD (Alkyl Ketene Dimer) latex. The method comprises the following steps: taking AKD as a raw material, carrying out pre-dispersion under the action of dispersing agent (modified polyamide) and protective colloid, and carrying out homogeneous treatment, so as to obtain the AKD latex. The AKD latex prepared according to the method can serve as an internal sizing agent and a surface sizing agent, so as to greatly improve the water resistance of paper and paper boards, and has the characteristics of high sizing effect and slaking speed, low impact on paper strength, environmental protection, high efficiency and the like.

Description

technical field [0001] The invention belongs to the field of papermaking chemicals, and in particular relates to an AKD emulsion and a preparation method thereof. Background technique [0002] AKD is the abbreviation of alkyl ketene dimer. It is a waxy solid at room temperature. The AKD emulsion prepared by heating and emulsifying with an emulsifier is a high-efficiency sizing agent that can improve the water resistance of paper and cardboard. The sizing effect of AKD has not been completed after the paper sheet is dried, and only about 80% of it is completed after 24 hours of storage after coiling. After several days, the sizing reaction is still going on, so the AKD sizing process usually adds a curing accelerator. At present, emulsified AKD is mainly used for internal sizing, while the main components of surface sizing agents are basically polymers or mainly polymers, and the cost is relatively high. [0003] In recent years, with the increase in the proportion of waste ...

AI Technical Summary

Problems solved by technology

[0004] (1) Since recycled pulp is used more and the source of waste paper is complicated, the volatility of pulp is increased, which also leads to the instability of sizing in pulp, and the effect of sizing in pulp is limited

[0005] (2) Adding in slurry increases the use of chemicals in the slurry system and affects the use of other chemicals (such as retention and drainage aids, enhancers, etc.)

[0006] (3) The one-way retention rate of the sizing agent in the slurry is preferably less than 90%, and many rosin sizing agents are only about 60%. The lost sizing agent will form various resins and anionic garbage in the slurry system After a certain period of accumulation, it will affect the water filtration and forming of the next paper, affect the strength of the paper, and even stain the net and felt, thus affecting normal production

The patent does not mention the possibility of using the AKD emulsion as a surface sizing agent, nor does it mention the aging speed and specific sizing effect of the AKD emulsion

At the same time, this patent uses a large amount of co-solvents in the preparation of amphoteric polymer surfactants, which is not environmentally friendly and economical

[0011] There are also some AKD emulsions mentioned in other patents and literatures, which have some problems in terms of curing speed, sizing effect, cost performance, environmental protection, etc.