Heavy calcium carbonate can increase the volume of plastic products, reduce costs, improve hardness and stiffness, reduce the shrinkage rate of plastic products, and improve dimensional stability; improve the processing performance of plastics, improve its heat resistance, improve the astigmatism of plastics, anti- At the same time, it has obvious effects on the toughening effect of notched impact strength and the viscous flow during the mixing process.

Mechanical properties

Calcium carbonate has been used as an inorganic filler in plastic filling for many years. In the past, calcium carbonate was generally used as a filler for the main purpose of reducing costs, and received good results. In recent years, with the extensive use in production and a large number of researches, it is also possible to fill a large amount of calcium carbonate without significantly reducing the production

After filling with calcium carbonate, due to the high hardness of calcium carbonate, the hardness and stiffness of plastic products will be improved, and the mechanical properties will be enhanced. The tensile strength and flexural strength of the product have been improved, and the elastic modulus of the plastic product has been significantly improved. Compared with FRP, its tensile strength, flexural strength and flexural modulus are roughly the same as those of FRP, and the thermal deformation temperature is generally Higher than FRP, the only thing inferior to FRP is its lower notched impact strength, but this disadvantage can be overcome by adding a small amount of short glass fibers.

For pipes, filling calcium carbonate can improve several of its indicators, such as tensile strength, steel ball indentation strength, notched impact strength, viscous flow, heat resistance, etc.; but at the same time it will reduce several of its toughness indicators, Such as elongation at break, rapid cracking, impact strength of simply supported beams, etc.

Thermal performance

After adding fillers, due to the good thermal stability of calcium carbonate, the thermal expansion coefficient and shrinkage rate of the product can be reduced in the same way, unlike glass fiber reinforced thermoplastics, which have different shrinkage rates in different aspects. Afterwards, the warpage and curvature of the product can be reduced, which is the biggest feature compared with the fiber filler, and the thermal deformation temperature of the product increases with the increase of the filler.

radioactivity

The filler has a certain ability to absorb rays, and generally can absorb 30% to 80% of incident ultraviolet rays to prevent the aging of plastic products.

Calcium carbonate has been used as an inorganic filler in plastic filling for many years. In the past, calcium carbonate was generally used as a filler for the main purpose of reducing costs, and received good results. In recent years, with the extensive use in production and a large number of research findings, filling a large amount of calcium carbonate can also not significantly reduce the performance of the product, and even greatly improve some aspects, such as mechanical properties, thermal properties, etc.
In the actual use process, calcium carbonate is generally not directly added to the plastic. In order to make the calcium carbonate evenly dispersed in the plastic and play a role in optimizing the performance, the surface activation treatment of the calcium carbonate must be carried out first.

According to the molding process and performance requirements of the final plastic product, calcium carbonate with a certain particle size is selected, first activated and treated with auxiliary agents such as coupling agent, dispersant, lubricant, etc., and then a certain amount of carrier resin is added to mix evenly. Screw extruder to extrude and granulate to obtain calcium carbonate film masterbatch. In general, the calcium carbonate content in the masterbatch is 80wt%, the total content of various additives is about 5wt%, and the carrier resin is 15wt%.
The addition of calcium carbonate can greatly reduce the cost of plastics

Calcium carbonate is extremely abundant and its preparation is very simple, so the price is relatively cheap. In terms of special materials for pipes, the price of polyethylene (with carbon black) at home and abroad is high, and the price is very different from calcium carbonate. The more calcium carbonate is added to the plastic, the lower the cost.

Of course, calcium carbonate cannot be added indefinitely. Considering the toughness of plastic products, the filling amount of calcium carbonate is generally controlled within 50wt% (data provided by calcium carbonate filler manufacturers). For the production of plastic and steel-plastic composite pipes, plastics are the main raw materials, and greatly reducing the cost of plastics will undoubtedly greatly reduce the production cost and be beneficial to the improvement of profits.