Types and applications of dispersants for plastics

Dispersant is a surfactant that has two opposite properties: lipophilicity and hydrophilicity within the molecule. It can uniformly disperse the solid particles of inorganic and organic pigments that are difficult to dissolve in liquids. It can also prevent the settling and agglomeration of solid particles and form the necessary chemicals for stable suspensions. Today I will introduce youdispersant types and applications:

1. Fatty acids, aliphatic amides and estersDispersant

StearamideDispersantUsed together with higher alcoholdispersantto improve lubricity And thermal stability, dosage(mass fraction, the same below) 0.3%-0.8%, it can also be used as a slip agent for polyolefins; hexenyl bis Stearamide, also known as ethylene bisstearamide, is a high melting point lubricant with a dosage of 0.5% to 2%;

Stearic acid monoglyceride, tristearic acid glyceryl; oleic acid acyl dosage 0.2% ~ 0.5%; hydrocarbon paraffin solid, melting point is 57 ~ 70 ℃, insoluble in water, soluble in organic solvents, the dispersion, compatibility, and thermal stability of the resin are poor, and the dosage is generally below 0.5%

2. Paraffin waxDispersant

Although paraffinDispersantIt is an external lubricant, but it is a non-polar linear hydrocarbon and cannot wet the metal surface. That is to say, it cannot prevent polyvinyl chloride and other resins from adhering to the metal wall. It can only be combined with stearic acid, calcium stearate, etc. When used, synergistic effects can be achieved.

Liquid paraffin: freezing point -15–35℃, poor compatibility with resin during extrusion and injection molding, the addition amount is generally 0.3 %-0.5%. If it is too much, it will worsen the processing performance.

Microcrystalline paraffin: Obtained from the petroleum refining process. It has a relatively large molecular weight and many isomers. The melting point is 65-90°C and has good lubricity. It has good thermal stability, but poor dispersion. The dosage is generally 0.1%-0.2%. It is best to use it together with butyl stearate and higher fatty acids.

3. Metallic soapsDispersants

Metal salts of higher fatty acidsDispersants, called metal soap, such as barium stearate, suitable for a variety of plastics, the dosage is about 0.5%; stearin Zinc acid is suitable for polyolefins, ABS, etc., with a dosage of 0.3%; calcium stearate is suitable for general plastics, for external lubrication, with a dosage of 0.2%-1.5%; other stearic acid soaps such as cadmium stearate and magnesium stearate , copper stearate.

4. Low molecular weight wax dispersants

Low molecular wax dispersants are based on various polyethylene (homopolymer or copolymer), polypropylene, polystyrene or other polymer modifications As raw materials, it is cracked and oxidized to form a series of oligomers with different properties.

Its main products include: homopolymer, oxidized homopolymer, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, low molecular ionomer, etc. kind. Among them, polyethylene wax, the chemical name of polyethylene wax is polyethylene glycol, and the English name PEG (Poly Ethylene Glycol) is the most commonly used