A kind of preparation method of polyhexamethylene biguanide hydrochloride

Abstract

The invention provides a method for preparing polyhexamethylene biguanide hydrochloride, the method comprising the following steps: (1) polycondensation reaction: first, 1,6-hexamethylenediamine hydrochloride, 1,6-dicyano Put guanidine hexane and water into the autoclave, ventilate nitrogen to maintain a certain pressure in the still, stir and raise the temperature to react; (2) salting out: reduce the temperature in the still, add water to dissolve the material, then add sodium chloride, leave standstill after stirring, The lower water layer is separated, and the crude product of polyhexamethylene biguanide hydrochloride in the upper layer is set aside; (3) pH adjustment: the crude product of the upper layer is dissolved in water, and the pH value is adjusted with hydrochloric acid solution to obtain polyhexamethylene biguanide hydrochloride Aqueous solution; (4) drying: drying the aqueous solution to obtain solid polyhexamethylene biguanide hydrochloride. The invention overcomes the disadvantages of difficult removal of solvents and small molecular impurities in the prior art, has mild reaction conditions, simple preparation method, the purity of the obtained product is over 98%, and the yield can reach over 96%, which is suitable for large-scale industrial production and application.

Description

technical field [0001] The invention relates to a preparation method of polyhexamethylene biguanide hydrochloride, which belongs to the technical field of preparation of guanidine-based polymer functional materials. Background technique [0002] Since the bactericidal properties of guanidine-based polymers were reported in 1930, they have been widely used in medicine, plant protection, industrial manufacturing, daily necessities, and food. ICI Corporation of the United States successfully prepared polyhexamethylene biguanide hydrochloride (PHMB) for the first time in the 1970s. PHMB is recognized as the safest and most efficient broad-spectrum antibacterial agent in the 21st century. It is colorless and odorless, has low inhibitory concentration, broad-spectrum and low toxicity, fast action speed, low foam volume, and can form a layer of cations on the surface of objects after use. The film has long-term antibacterial properties and will not cause bacterial resistance. It i...

AI Technical Summary

Problems solved by technology

[0006] The weak point of above-mentioned synthetic PHMB method is: melt polymerization method, when temperature of reaction is lower, the transformation rate of raw material is lower, and molecular weight is also lower; When temperature of reaction is higher, although the molecular weight of product can be improved, also can To a certain extent, the conversion rate of raw materials is improved, but it is easy to produce products with branched chains or crosslinks; no matter the reaction temperature is high or low, these methods will generate inorganic ammonium salts, oligomers or byproducts with branched chain crosslinks, which are very It is difficult to completely separate from the product by a more economical method, which reduces the use effect and increases the cost of use; in the solution polymerization method, a solvent with a high boiling point is generally added as a reaction solvent, which can alleviate the crosslinking reaction during melt polymerization to a certain extent. However, the introduced high-boiling-point solvent is not easy to remove, which affects the quality of the final product and increases energy costs

This method needs to distill high-boiling polyhalogenated hydrocarbons, which consumes a lot of energy and is complex in process.