Wax is a complex mixture of organic compounds. Different kinds of waxes have different compositions and properties. They are classified according to their sources, mainly including natural waxes and synthetic waxes. The former comes from natural existence, and there are mainly three kinds: animal wax, plant wax and mineral wax; The latter comes from synthetic preparation, which is actually a compound with fixed chemical and physical properties, such as polyethylene wax, polypropylene wax and so on. Blended wax is the most widely used in various industries in China, and its performance is significantly improved compared with ordinary wax. However, with industrial development and technological progress, blended wax is no longer applicable in many fields, and modified wax came into being.
Modified wax is a product obtained by chemical modification of non-polar wax. It does not belong to natural wax or synthetic wax, but between them. After the groups – Oh, – COOH, – coor, – CONH, – coch3, etc. are introduced, they act, resulting in the change of its surface properties. Not only the solubility and lubricity are improved, but also the emulsification and dispersion are improved, which greatly expands its application field.
The formation of emulsified wax is mainly due to the addition of emulsifier, and the surface tension of wax / water two phase is reduced under the action of emulsifier, then stir or take the similar way to disperse wax in water until uniform, forming stable emulsion. It is generally believed that there are two main types of lotion: W/O and O/W. Its composition largely determines its specific type. The research shows that the critical oil phase volume fraction is 25.98% and 74.02% respectively. If it is less than 25.98%, only O / W type is formed; Similarly, other types are also determined. If it is greater than 74.02%, only w / O type is formed; Between the two, the two types coexist. O / W type is more common in practical application.
Emulsification method is the key in the production and preparation process of emulsified wax. It is necessary to prepare stable wax emulsion with semi transparent or white sticky lotion and P H value about neutral, which does not appear stratification or floating wax for a period of time. The most important thing is how to select emulsifiers. Generally, according to the HLB value, specifically, the promotion effect of hydrophilic part and lipophilic part on the improvement of surfactant molecular properties is usually measured by this physical quantity. The matching degree of HLB value between emulsifier and wax lotion is directly proportional to the emulsifying performance of two emulsions, that is, the high matching degree can be used as the best emulsifier. In practical application, a single emulsifier can not meet the emulsification requirements. For HLB value, if one is too large and the other is too small, the two can be mixed and compounded according to additivity, and the emulsification effect will be better.
The preparation methods of emulsified wax are constantly developing and improving. The following methods can be adopted: primary soap method, liquid addition method in turn, agent in water method, agent in oil method and phase inversion emulsification method [6]. Lotion lotion lotion is usually prepared by preparing W/O lotion first and then converted to O/W emulsion. The general steps are as follows: first, under the heating condition, melt the main components (wax, emulsifier and auxiliary), add a little hot water, mix the W/O emulsion evenly under the action of external force, then add the remaining hot water as soon as possible, and emulsify evenly under the action of the emulsifier such as high-speed distributor, and then generate O/W emulsion. After cooling, emulsified wax is obtained.
Emulsified wax is non-toxic and non corrosive, and has good compatibility with aqueous solution or emulsion. It is convenient, fast and safe in production, preparation and use. Its price is also relatively low, so it is more widely used. However, emulsified wax is not easy to store, which is affected by the nature of the wax itself, but also related to the type of emulsifier in the emulsification reaction, the mass fraction of wax, emulsification temperature, etc. the stability will decline after long-term storage, which will have a great impact on its service performance.
The research of wax lotion has begun since 1950s, and a series of series have appeared and developed. Hi Wax super wax series (Japan) and A C wax series (USA) are more representative. Specifically, the use of modified wax accounts for a large proportion in Japan. The use of oxygen containing wax alone exceeded 10000 tons in the early 1980s. With the deepening of research on the application field of wax lotion, the production of emulsified wax has been more and more prosperous, and the technical content and added value of products have been steadily improved, and a special wax system that can meet various needs has been formed gradually. For example, nano wax lotion has a good film forming and gloss, and is widely used in various industries. At present, China has begun to attach importance to the research of modified wax to make up for the late start of the research and development of wax emulsion in China. Lotion, acidified wax and saponified wax have been studied and prepared, and they are widely used in daily chemical, leather, textile and other industries as glazing agents, pigment dispersants, lubricants and rust inhibitors. However, generally speaking, there is still a large gap between China and developed countries in research and production. The varieties and quantity of modified wax developed are relatively small, and it is difficult to fully meet the requirements of the market in terms of quality and scale, so it still needs to be imported in the short term .
