Factors that are more susceptible to influence in the production of plastic products

Fillers, also known as fillers and fillers, are solid substances added to the matrix of polymer materials to reduce costs and/or improve some properties of products. The main factors to be considered when choosing fillers are as follows:
1. Low Price
The price of filler has a great influence on the cost of plastics. The proportion of polyvinyl chloride plastics with fillers is 2-3 times that without fillers. Therefore, the proportion of polyvinyl chloride plastics with fillers increases rapidly with the increase of the amount of fillers. Therefore, the cost based on weight is not as accurate as that based on volume. In application, the volume cost must be considered. The small proportion of filler is more advantageous to the volume cost.
2. Oil Absorption
That is, the ability of fillers to absorb plasticizers. It depends on the fineness of filler and the variety of filler and plasticizer. The cost of plastics increases with the increase of oil absorption.
3. Electrical Performance
The electrical insulation of plastics can be improved by adding calcined clay, which removes crystalline water and other impurities from kaolin during calcination. The temperature of forging affects the electrical insulation of plastics, which is generally in the range of 600 700 C. Good results can be obtained. Fillers can also improve the thermal deformability of cable materials. Adding a small amount of carbon black can improve the weather resistance of plastics. A large amount of carbon black can reduce the electrical insulation and prepare semiconductor polyvinyl chloride plastics. The filler with low water absorption is beneficial to electrical insulation.
4. Influences on Physical Properties
In soft PVC plastics, the tensile strength, tear strength and elongation decrease while the hardness increases with the increase of filler dosage. When the filler with larger particles is used, the loss of tensile strength and tear strength is greater, while when the filler with finer particles is used, the elongation decreases greatly.
The hardening effect of pottery clay on PVC plastics is greater than that of calcium carbonate, that is to say, the hardness increases greatly and the elongation decreases greatly. Due to the different absorption, specific gravity, hardness, dispersibility, particle size and particle size distribution of plasticizers, the effects on the physical properties of plastics are also different.
5. Purity
Because plastics may react with impurities in fillers, the purity of fillers is required. It has been proved that metal impurities have a negative effect on the stability of barium/cadmium system. Trace amounts of iron, manganese, copper and a small amount of aluminium have a great influence on the efficiency of plasticizers. The existence of sulphur results from sulphide formation, which pollutes lead stabilizers. When calcium carbonate is used in white or other light-colored polyvinyl chloride products susceptible to infection, the content of trace elements is recommended to be limited to the following limits:
The fillers widely used in the processing of PVC plastics are calcium carbonate, clay, barium sulfate, titanium dioxide and so on. Barium sulfate, titanium dioxide and calcium carbonate are mainly used in hard plastics. Calcium carbonate ceramics are mainly used in soft plastics. It is advantageous to add calcined clay in insulating cables. Calcium carbonate is mainly added in protective cables. Aluminum hydroxide, calcium carbonate and talcum powder are also added in films to reduce costs.
The development direction of filler is to make filler surface coated by various methods in the preparation process. The main advantages of surface treatment of calcium carbonate are: reducing the tendency of caking and improving the processing performance, which is beneficial to the development of plastic processing to continuous high-speed extrusion process. Other advantages of calcium carbonate coated with stearate are: small oil absorption can reduce the amount of plasticizer; satisfactory and effective hydrophobicity and appropriate low content of plasticizer, which also improve the electrical properties; due to the supplementary stabilization of calcium stearate in the coating layer, it improves the thermal stability; and in plastic processing. There is no need to add lubricant, which can simplify the batching process.
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