Polyacid homopolymer dispersants, such as Tamol 1254 and Tamol 850, Tamol 850 is a methacrylic acid homopolymer. Multi-acid copolymer dispersants, such as Orotan 731A, which is a copolymer of diisobutylene and maleic acid.
These two types of dispersants are characterized by strong adsorption or anchoring effect on the surface of pigments and fillers, long molecular chains to form a spatial site resistance, chain ends with water solubility, and some are supplemented by electrostatic repulsion to achieve a stable result. To make the dispersant with good dispersion, the molecular weight should be strictly controlled. If the molecular weight is too small, the spatial site resistance is insufficient; if the molecular weight is too large, flocculation will occur. For polyacrylate dispersants, the degree of polymerization is 12-18 to achieve the best dispersion effect.
Organometallic layer silicate
The organometallic layer silicate comes from china clay ore , mainly in the natural deposits of Wyoming in the United States and Msborg in Germany. It is called bentonite, and is made of [SiO,] or [(Si, Al)O: ] Tetrahedron and [AI(O,OH)6] octahedron are used as block units. The well-known layered silicate is a charged three-layer ore such as saponite, montmorillonite, and hectorite, in which the octahedron forms the middle layer, and the two sides are surrounded by two layers of tetrahedrons like a sandwich. Part or all of the charge of each layer is replaced by eight coordination, with Al3+ or other low-charge ions in the middle, such as Mg 2+, Zn²+, Ni²+ or Lit. Negative charges and cations, such as Nat or Ca²+, are obtained from this lattice, so that compensation can be obtained.
These cations can be replaced with quaternary ammonium compounds for organic modification, such as dimethyl distearate distearate ammonium chloride and dimethylbenzyl ammonium stearate chloride. By adding these cationic surfactants, these particles can be wetted by the solvent and can be miscible in the solvent system. When a shear force is applied, the outside is wetted and the plies are separated. Adding polar solvents such as ethylene glycol, propylene carbide or acetone, and adding a small amount of water can wet the inside of the particles. This process is called polar activation. In this process, the distance of each piece increases. If the shear force is further increased, it will eventually lead to all separation. The hydrogen bonds of internal molecules between the terminal hydroxyl components can form rheology and gelation phenomena. During painting (or brushing, or spraying) ptfe wax price construction, the structure is destroyed, and the viscosity is restored after the film is formed.
Organometallic layer silicate has strong thixotropy and short viscosity recovery time. Its working principle is similar to anti-settling agents such as hydrogenated castor oil. Because it has good compatibility with most base materials, usually gloss and distinct image (DOI) are slightly better.
Leave a message
We’ll get back to you soon