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Introduction of dispersants for plastics

Views:0 Publish Time: 2022-03-15 : Louis Lu

Introduction of dispersants for plastics

Introduction of dispersants for plastics

Dispersant is a kind of surfactant with two opposite properties of lipophilicity and hydrophilicity at the same time in the molecule. It can uniformly disperse the solid particles of inorganic and organic pigments that are difficult to dissolve in liquids, and can also prevent the sedimentation and agglomeration of solid particles to form a stable suspension.

 

Product Category

1Fatty acids, fatty amides and esters

Stearamide and higher alcohol can be used together to improve lubricity and thermal stability. The dosage (mass fraction, the same below) is 0.3%-0.8%, and it can also be used as a slip agent for polyolefins; Hexenyl bis-stearamide, also known as ethylene-based bis-stearamide, is a high melting point lubricant, the dosage is 0.5% to 2%; stearic acid monoglyceride, tristearic acid glycerideThe dosage of oleic acid acyl is 0.2%0.5%;Hydrocarbon paraffin solid, melting point is 5770℃, insoluble in water, soluble in organic solvent, dispersibility, compatibility and thermal stability in resin are all poor, the dosage is generally below 0.5%.

 

2Paraffin

Although paraffin is an external lubricant, it is a non-polar linear hydrocarbon and cannot wet the metal surface, that is to say, it cannot prevent resins such as polyvinyl chloride from adhering to the metal wallOnly when used together with stearic acid, calcium stearate, etc., can the synergistic effect be exerted.

liquid paraffinfreezing point -15--35°C, has poor compatibility with resin during extrusion and injection molding processing. The addition amount is generally 0.3%-0.5%. If it is too much, it will make the processing performance worse.

Microcrystalline ParaffinObtained from petroleum refining process, its relative molecular mass is relatively large, and there are many isomers, melting point is 65-90 ℃, lubricity and thermal stability are good, but the dispersibility is poor, the dosage is generally 0.1%-0.2%,preferably used in combination with butyl stearate and higher fatty acids.

 

3metal soap

The metal salts of higher fatty acids are called metal soaps. For example, barium stearate is suitable for various plastics, and the dosage is about 0.5%; zinc stearate is suitable for polyolefin, ABS, etc., and the dosage is 0.3%; Calcium stearate is suitable for general plastics, external lubrication, the dosage is 0.2%-1.5%; other stearic acid soaps such as cadmium stearate, magnesium stearate, copper stearate.

 

4low molecular weight wax

Low molecular weight wax is made of various polyethylene (homopolymer or copolymer), polypropylene, polystyrene or other polymer modified productsa series of oligomers with different properties are formed by cracking and oxidation.

Its main products are: homopolymer, oxidized homopolymer, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, low molecular ionomer and other five categories. 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.

 

Product Action

1Improve the gloss and increase the leveling effect. The gloss actually mainly depends on the scattering of light on the surface of the coating (that is, a certain level of flatness)

2Prevent floating color

3Improve tinting strength Note that tinting strength is not as high as possible in an automatic grading system

4Reduce viscosity, increase pigment loading

5This is the case to reduce flocculation, but the finer the particle, the higher the surface energy, and the dispersant with higher adsorption strength is required, but the dispersant with too high adsorption strength may cause adverse effects on the performance of the coating film

6Increase storage stability

7Increase color development, increase color saturation.

8Increase transparency (organic pigments) or hiding power (inorganic pigments).

 

Purchase requirements

1Good dispersion performance, preventing filler particles from agglomerating with each other

2Appropriate compatibility with resins and fillers, good thermal stability;

3Good fluidity during molding and does not cause color drift;

4Does not affect the performance of the product, non-toxic and cheap;

5The amount of dispersant is generally 5% of the mass of the masterbatch.

 


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