Cationic polymer and preparation method thereof

Abstract

The invention discloses a cationic polymer and a preparation method thereof, and belongs to the technical field of water-soluble polymer preparation. The preparation method comprises the following steps: adding a dimethyl diallyl ammonium chloride monomer into a reaction kettle, adding the viscosity regulator, the metal ion chelating agent, the chain transfer agent and the deionized water while stirring to prepare a polymerization solution, and introducing nitrogen to expel air; raising the temperature to 75-95 DEG C, and starting to dropwise add an initiator and a dimethyl diallyl ammonium chloride monomer for 2-4 hours at a preset speed; dropwise adding a curing agent at 75-105 DEG C, curing for 1-3 hours, and adding water for dilution to obtain a target product. The viscosity regulatoris added into the reaction system, so that the product is kept in a flowing state when being polymerized to a relative high molecular weight, the dispersion of the initiator and the curing agent and the diffusion of free radicals are facilitated, and the residual monomer removal efficiency and effect are improved.

Description

technical field [0001] The invention belongs to the technical field of water-soluble polymer preparation, in particular to a cationic polymer and a preparation method thereof. Background technique [0002] Dimethyl diallyl ammonium chloride polymer is widely used in oil fields, papermaking, mining, textile printing and dyeing, water treatment and daily chemical products due to its stable structural unit, high cationic charge density, controllable molecular weight and low toxicity. and other fields. The commercial products of this kind of cationic polymer generally have the form of aqueous solution, solid dry powder and so on. Products in the form of aqueous solution are easy to use and more widely used. With people's emphasis on the environment and health and safety, low monomer residues are getting more and more attention. Therefore, some researchers have also begun to pay attention to the research of low-residue single DMDAAC polymers. Generally, high-temperature curing...

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Problems solved by technology

Therefore, some researchers have also begun to pay attention to the research of low-residue single DMDAAC polymers. Generally, high-temperature curing agents and prolonged time are used to reduce residual monomers. Some researchers also use purified DMDAAC monomers to produce low-residue monomers. samples, but the above-mentioned method has raw materials that are too harsh in the process of industrialization, or excessively prolonging the reaction time affects production efficiency

[0003] After long-term practice, the applicant found that the existing technology mainly has the following defects: 1. The reaction process time is too long, and the time is as long as 53 hours. Even after industrialization, the production efficiency is very low and the production cost is high

2. The requirements for raw materials are extremely high, and the industrial dimethyl diallyl ammonium chloride monomer is used after distillation and dehydration to 70-85%, and the industrialized dimethyl diallyl ammonium chloride monomer The impurity content of the material is significantly lower than the industrial level, and the requirements for raw materials are too harsh, so it is difficult to realize industrialization

3. Although some literature methods have greatly reduced the process time and effectively improved the production efficiency, the amount of residual monomers is too high or the upper limit of the molecular weight that can be achieved is too low

4. When preparing relatively high molecular weight products, the products are generally in the form of rubber blocks, and the way to improve the conversion rate is generally to embed a large number of high-temperature initiators. However, the embedded high-temperature initiators not only easily cause safety problems when the polymerization temperature is out of control, but also Due to the solid state of the product, it seriously affects the diffusion of free radicals and affects the effect of reducing residual monomers