The grade of dispersant is mainly divided into polymer dispersant and low molecular dispersant. The latter is a low-end product. Their prices vary several times. Polymer dispersant is also called Hyperdispersant. This name is the original commodity name of ICI company. It's not a technical concept. However, it is now widely used as a substitute for polymer dispersant. Polymer dispersants have the following advantages and identification methods.
1. Polymer auxiliaries have better dispersing activity. Under the same processing viscosity, the pigment content in the abrasive can be greatly increased. Thus the machining efficiency is mentioned. Or at the same pigment content, it has lower viscosity. From this point of view, we can also distinguish polymer dispersant and low molecular dispersant. Especially, it is easy to distinguish carbon black which is difficult to disperse. Low molecular dispersant can not get high pigment color paste. This is the case with solvent based coatings. The color paste of water-based coating does not have this characteristic. Generally, carbon black should be used for this kind of grinding test. As long as the carbon black is passed, other pigments will be fine. During the experiment, add as many pigments as possible under the specified process (such as sanding machine) viscosity.
2. It can show the original color phase of high-grade pigment, and the obtained color paste and coating have good stability. It can be stored for a long time. The coating prepared with low molecular dispersant has poor stability. In particular, the test is carried out under cold and hot circulation conditions, and the latter is very quick to reverse coarsening or flocculation.
3, polymer dispersant are similar to the characteristics of resin. Its molecular weight reaches or even exceeds that of coating resin. According to this, it can be easily identified. Take 1-2g of auxiliary agent and dry it in oven or normal temperature to remove solvent. The obtained residue is the bulk of dispersant. If it is a solid resin film, it is a polymer dispersant. Otherwise, if it's still a fluid, it's a low molecule.
It should be noted that if the dried resin film is a transparent and brittle hard resin, it is still not a concept polymer product, which is a kind of modified acrylic resin. It can be regarded as a quasi polymer assistant. It has certain dispersing activity. For example: Deqian dp-983, etc. Standard concept: the resin film formed by drying polymer dispersant is light yellow or yellow. It is soft and sticky or has toughness and superior performance.
4. Look at the composition. Generally, due to the high viscosity of polymer dispersant, the products with high content can not be obtained. Most of the active ingredients are less than 50%. But some brands make some fake polymer products according to this. This is also the form of composition. But as long as the third method is used, drying can identify.
At present, there are some products on the market that claim to be able to replace some advanced brand products. The reason is often the case that users use inorganic pigments. Such as titanium dioxide, or iron oxide pigments. We know that inorganic pigments are the most easily dispersed pigments. Good dispersion can be achieved by using low molecular dispersant. The use of polymer dispersants can certainly be better dispersion. But there is little difference. So some businesses confuse the public with this.