Knowledge of plastic fillers

1, the basic characteristics of the filler

Maintain chemical and physical stability during plastic processing and use;

Improve certain properties of the resin: increase rigidity, improve heat resistance, and improve electrical insulation;

Improve weather resistance and increase dimensional stability;

Tinting strength, thermal conductivity, electrical conductivity, flame retardancy; low price.

2, the basic requirements of fillers

Chemically stable, relatively high purity, low impurity content;

The color should be white or light as much as possible, and it does not contain iron and other impurities that are easily heated and yellowed;

Does not cause serious damage to the physical and chemical properties of plastic products;

Easy to disperse and mix, with appropriate particle size;

The oil absorption value is relatively low, and has no significant effect on the processability;

Have a suitable crystal structure; have a lower Mohs hardness;

There is a relatively cheap price compared to resin.

3. Classification of fillers

They are generally classified into mineral, vegetable fillers and industrial fillers depending on their source. The latter can be divided into synthetic and waste slag types.

According to the shape, it is divided into a powder, a sphere, a sheet, a column, a needle, and a fibrous filler.

According to its performance, it is divided into incremental, reinforcing and functional fillers.

It is classified into an inorganic filler and an organic filler according to its chemical composition.

The fillers used in plastics are classified according to their chemical composition as follows:

Oxide: silica, alumina, diatomaceous earth, iron oxide, zinc oxide, magnesium oxide, cerium oxide, titanium dioxide, antimony trioxide, barium ferrate, barium ferrate, alumina fiber.

Hydroxide: aluminum hydroxide, magnesium hydroxide, or basic magnesium carbonate.

Carbonate: dolomite, calcium carbonate magnesium carbonate, basic sodium carbonate.

(Sub)sulfate: barium sulfate, calcium sulfate, ammonium sulfate, calcium sulfite.

Silicate: talc, clay, mica, asbestos, calcium silicate, montmorillonite, glass beads, glass fiber, bentonite.

Carbon: carbon black, graphite, carbon hollow spheres, carbon fiber.

Others: zinc borate, calcium borate, sodium borate, barium metaborate, potassium titanate.

Organic matter: peanut shell, wood flour, bamboo powder, paper, pulp, straw, straw, starch, rayon, synthetic fiber, etc.

4. The influence of inorganic fillers on the properties of products:

The specific gravity increases as the amount of filler added increases.

The surface hardness increases as the amount of filler added increases.

The rigidity increases as the amount of filler added increases.

The flexural strength decreases as the amount of filler added increases.

The elongation at break decreases as the amount of filler added increases.

The surface gloss decreases as the amount of filler added increases.

The impact strength generally decreases with the addition of the filler; if the shape of the filler is needle-like or fibrous, it is generally enhanced.

The temperature resistance increases as the amount of filler added increases.

5. The influence of organic fillers on the properties of products:

Generally, the addition of organic fillers has a great influence on the physical and mechanical properties of plastics. For the time being, no general rule has been found (sometimes also affects chemical properties). There are roughly the following commonalities:

The specific gravity of the article decreases as the amount of filler added increases.

The surface gloss of the article decreases as the amount of filler added increases.

The impact strength of the product generally increases with the addition of the filler; especially when the powder is acicular or fibrous, it is generally enhanced.

6, the characteristics of the filler required in practical applications:

Particle size and particle size distribution.

Crystal structure.

Oil absorption.

Dispersibility.

Viscosity characteristics.

Rigidity and hardness.

Electrical performance.

1) The product has high chemical stability, good heat resistance, no decomposition at processing temperature, and does not affect the original physical and mechanical properties of the plastic resin. After the addition, the whitening phenomenon caused by bending and stretching of the product is small.

2) No chemical reaction occurs after the product is mixed with other processing aids.

3) The product has good dispersion and mixing in the plastic resin, does not affect the processing performance, and has little wear on the equipment.

4) The amount of oil absorbed by the product and the amount of plastic resin absorbed are small.

5) The product does not contain impurities that promote accelerated decomposition of the resin.

6) The product is insoluble in water, grease, all solvents, does not absorb moisture, does not contain crystal water (except flame retardant), acid and alkali.

7) The product filler powder has uniform appearance and uniform particle size.

8) The products are cheap and abundant in source, and the quality fluctuation between different batches of fillers is small.