A manufacturer specializing in plastic products

The editor of the folding turnover box manufacturer introduces the purpose and technical means of polymer blending modification

by:Qusheng     2021-03-05
The editor of the folding turnover box manufacturer introduces the purpose and technical means of polymer blending modification. Blending modification technology Plastic blending modification refers to a modification method that mixes one or more other resins (including plastics and rubber) into a resin to change the properties of the original resin. Plastic blending modification is an effective process of processing multiple components of raw materials into more uniform and practical products. The main physical reaction in this process, and a small amount of chemical reaction. We expect more chemical reactions than physical reactions. Regardless of whether it is a physical or chemical reaction, the materials are required to be fully mixed and rolled, so there is a blending equipment-a vertical high-speed mixer. The purpose of polymer material blending modification: (1) To improve certain physical and mechanical properties of polymer materials ① Improve toughness (improve impact resistance) ② Improve heat resistance ③ Improve dimensional stability ④ Improve wear resistance ⑤ Improve resistance Chemical resistance (solvent resistance) ⑥ Other physical and mechanical properties, such as air tightness, weather resistance, flame retardancy, damping, adhesion, antistatic, biocompatibility, etc. (2) Improve the processing performance of polymer materials ① Improve the melt fluidity of polymer materials, that is, change the melt viscosity of the polymer through blending. ② Control the crystallization behavior of crystalline polymers. (3) Cost reduction Under the premise of ensuring the performance of the material, low-priced components are filled to reduce the cost of the material. (4) Endow polymer materials with certain special properties. Certain applications require polymer materials with certain special properties, such as flame retardancy, conductivity, damping, etc. The materials can be made to have the properties by adding components with corresponding characteristics. characteristic. Technical means of blending modification: 1. Pretreatment-moisture pretreatment: Both polymers and additives have water absorption, and temperature fluctuations and moisture in the warehouse may be caused by the moisture absorption of raw materials, molten polymers, such as nylon, polyester For materials that are extremely sensitive to moisture, the presence of moisture will cause their degradation, leading to the deterioration of various performance indicators and even processing failure. At present, the most practical drying method is hot air circulation drying. 2. Pre-mixing: For a single screw, the feeding capacity greatly affects the mixing effect. In many cases, even simple color processing will cause the color difference of the same batch of materials before and after the same batch and post-processing due to uneven mixing. Color inhomogeneity; for the twin screw, although the feeding ability basically does not affect the mixing effect, and in order to measure accurately, in theory, all components should be separately metered and fed separately at the feeding port. But this means that multiple precision feeders are required, which is very uneconomical for the blender, so we mostly pre-mix before processing two-component and multi-component materials. The current mixing equipment is mostly vertical high-speed mixers. 3. Dispersion and mixing: Dispersion and mixing is to reduce the particle size of the components, to break solid blocks or aggregates into particles, or the dispersed phase size of incompatible polymers to reach the required range. This process usually relies on a kneading disc with a large thickness and a large angle. 4. Distributive mixing: Distributive mixing is to make the spatial distribution of individual components uniform. Ensure the uniform distribution of the components in the melt passing through the distribution element in the mixing equipment. This is usually achieved by kneading the disc at a narrow angle. In extreme cases, gear distribution components will be used first. 5. Residence time distribution: the same batch of materials are dispersed after passing through the feeding port, and the distribution mixing is finally extruded out of the mixing equipment. The main significance of this indicator is to evaluate the self-cleaning ability of equipment.
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