Yuan Lei little knowledge | filler selection of plastic product ingredients

Release time:

2024-03-21 16:19


Fillers are also known as fillers, whose main purpose is to reduce the cost of plastic products. Other positive effects are to improve the heat resistance, rigidity, hardness, dimensional stability, creep resistance, wear resistance, flame retardant, smoke and degradability of the product, reduce the shrinkage rate to improve the accuracy of the product; Side effects lead to a decline in some properties of the product or even a substantial decline, the most obvious decline in performance are impact strength, tensile strength, processing fluidity, transparency and product surface gloss.

Fillers can be divided into inorganic fillers and organic fillers two categories. The following is mainly to understand mineral fillers.

▼Barium sulfate

The surface gloss of barium sulfate filled composite is higher than other filling materials, and the application range is not wide, mainly used in several special fields. One is to use its high density to manufacture high-density plastic products such as speakers and fishing net drops; The second is to use it to absorb X-rays and Y rays to make radiation-proof plastic products; The third is used for sound absorption and heat conduction filling materials.

▼Calcium carbonate

It has the advantages of low price, wide source, non-toxic and tasteless, white color and easy coloring, low hardness, easy drying, high chemical stability, and has become the first category of fillers with the largest amount and the most widely used.

Depending on the density or the source, calcium carbonate can be divided into two categories: heavy and light. Heavy calcium carbonate is made by grinding and grinding natural calcite, and light calcium carbonate is made by calcination and other chemical processes using limestone as raw material. Heavy calcium carbonate is mainly used in PP plastic woven bags, woven fabrics, packing belts, PVC floor, floor leather, blinds, wall panels, LDPE garbage bags, etc. Light calcium carbonate is mainly used in PVC leather, pipe and profile, PE corrugated box and so on.

▼Talc powder

The composition of talc powder is 3MgO·4SiO2·H2O, and the structure is similar to mica, with a sheet structure. The appearance is white or light yellow fine powder, soft and greasy, which is conducive to the rigidity and heat resistance of composite materials, low hardness, certain lubricity, light wear to equipment, and is the second largest filler variety after calcium carbonate.

Because of the lamellar structure, the reinforcing effect of talc powder is larger than that of calcium carbonate, but when the filling amount is large, the welding performance of the product is affected. Talc powder has a blocking effect on infrared with a wavelength of 7 ~ 25um, and can be used for night heat preservation in agricultural greenhouses. Talc powder can be used as a nucleating agent for PP, and can also be used as a smooth agent for PO films.

Talc powder is the most used in PP modification, and is generally combined with elastomer materials to increase rigidity while toughening.


Kaolin is a kind of clay, also known as clay. The bound water contained in itself can be removed at high temperatures, but it is easy to absorb water in the air, so the kaolin used as a filler should pay special attention to the influence of water.

Ordinary kaolin. One is to use calcined kaolin to improve the insulation of plastics, and adding 10% calcined kaolin to PVC can improve the electrical insulation by 5 to 10 times. The second is to use it with talc powder, mica wavelength of 7 ~ 25um infrared blocking effect, used in agricultural greenhouse film thermos bottle agent. In addition, kaolin can also be used as a nucleating agent for PP.

 ▼Mica powder

There are many kinds of mica powder, and its industrial fragments can be used in plastic fillers by dry or wet grinding. The crystal shape of mica powder is flake, and its thickness to diameter ratio is large. If this thickness to diameter ratio can be maintained in the filling, the enhancement effect is significant, so it is called reinforcement filler.

Another feature of mica powder is that it has a blocking effect on the infrared ray with a wavelength of 7 ~ 25um, and its effect is better than talc powder and kaolin with similar functions, and its daylight transmission rate is higher than other filling materials, and it is most suitable for the daytime warming and night moisturizing of agricultural greenhouses. The surface energy of mica particles is high, and it is not easy to achieve coating and coupling treatment, so the amount has not been high, and it is only used for reinforcing or insulation of the film.

Mica powder is commonly used in PVC, PP, PE, ABS and PA, with the addition amount of 10% to 40%.      


Yuan Lei's Little Knowledge | Performance Requirements and Types of Fillers for Coatings


Fillers in coatings are usually white or slightly colored pigments with a refractive index less than 1.7. It has the basic physical and chemical properties of pigments used in coatings, but due to its refractive index being similar to the film-forming material, it is transparent in coatings and does not have the coloring and covering power of coloring pigments. It is an indispensable pigment in coatings.

Yuan Lei's Little Knowledge | Application Effects of Different Mineral Powder Materials in Coatings


In architectural coatings, commonly used mineral materials include barium sulfate, calcium carbonate, kaolin, mica powder, talc powder, quartz powder, silica micro powder, transparent powder, glass powder, wollastonite powder, etc. Reasonable application of various mineral materials can effectively improve or enhance the performance of coatings. Let's take a look at the application of different mineral materials in coatings.

Yuan Lei's Little Knowledge | Characteristics of Mineral Materials


Mineral materials refer to the material products obtained by processing and transforming natural minerals (mainly non-metallic minerals) or rocks as the main raw materials, or minerals or rocks that can be directly used as materials and aim to utilize their main physical and chemical properties. This meaning mainly includes the following four aspects: first, natural minerals and rocks that can be directly utilized or processed to be utilized; Secondly, finished or semi-finished materials made mainly from natural non-metallic minerals and rocks through physical and chemical reactions; Thirdly, artificially synthesized minerals or rocks; Fourthly, the direct utilization targets of these materials are mainly their own physical or chemical properties, not limited to individual chemical elements.