chenhtbb: 八月 2021

　　The yellowing of PVC profiles is mostly due to the presence of paste at the die. The reason is that the die runner is unreasonable or the local polishing in the runner is not good, and there is a stagnant area. The yellow line of PVC profile is mostly due to the presence of paste in the barrel. The main reason is that there is a dead corner between the sieve plates (or transition sleeves) and the material flow is not smooth. The yellow line is a vertical straight line on the PVC profile, the stagnant material is at the exit of the die; if the yellow line is not straight, it is mainly in the transition sleeve. Yellow lines appear when the formula and raw materials are unchanged, the reason should be found mainly from the mechanical structure, and the starting point of decomposition should be found and eliminated. If the reason cannot be found from the mechanical structure, it should be considered that there is a problem with the formula or process. The measures to avoid degradation include the following aspects:

　　Strictly control the technical indicators of raw materials and use qualified raw materials;

　　Formulate reasonable molding process conditions, under which PVC materials are not easy to degrade;

　　The molding equipment and mold should be well-structured, and the dead corners or gaps that may exist on the contact surface between the equipment and the material should be eliminated; the runner should be streamlined and the length is appropriate;

　　The heating device should be improved, the sensitivity of the temperature display device and the efficiency of the cooling system should be improved.

　Polyvinyl chloride PVC is an economical and general-purpose thermoplastic polymer, which is widely used in the construction and construction industries to produce door and window profiles, pipes, wire and cable insulation, and medical equipment. It is the world's three largest thermoplastic materials together with polyethylene and polypropylene. Due to the poor molding performance of the processed PVC profile, such as high melt viscosity, poor fluidity, poor thermal stability, easy thermal decomposition, poor aging resistance, easy to become brittle, hard, crack, and poor toughness, The cold resistance is not good, so PVC modification is generally required to make up for the above shortcomings.

　　Physical modification: Physical modification is to improve its performance by adding various additives or filling, blending, and strengthening.

　　1. For example, adding ACR to improve the molding and processing performance of PVC materials; adding internal and external lubricants or polyethylene wax to improve the viscosity and fluidity of the materials; adding thermal stabilizers to improve the thermal stability of the materials during molding and reduce their Decomposition temperature; adding antioxidants and anti-ultraviolet agents to improve the anti-aging life of PVC profile products; adding plasticizers to improve the plasticizing performance of materials and increase the softness of products. Filling modification is to improve certain properties by adding inorganic or organic fillers.

　　2. Such as adding wood powder filler to reduce the specific gravity of PVC products, close to wood; adding metal powder, such as copper powder, aluminum powder to improve the conductivity of the product; adding iron oxide magnetic powder to improve the magnetic properties of the product; adding calcium carbide to improve the product Hardness, while reducing material costs; adding red mud to improve the heat resistance and light aging resistance of the product, while reducing material costs.

　　3. For example, other polymers that can be blended and modified with PVC include acrylonitrile-butadiene-styrene copolymer (ABS), methyl methacrylate-butadiene-styrene copolymer (MBS), poly Acrylate, chlorinated polyethylene (CPE), ethylene-vinyl acetate copolymer (EVA), nitrile rubber, ethylene propylene rubber, chlorinated polyvinyl chloride (CPVC), dioctyl maleate, etc.

　　4. In addition, PVC modification methods such as reinforced modification, crosslinking modification, foaming modification, and radiation modification can also be used to improve the performance of PVC. For example, use mica powder with a large aspect ratio for reinforcement; use dicumyl peroxide (DCP) for cross-linking modification to increase strength; use azodicarbonamide foaming agent to reduce the specific gravity of PVC products, and use cobalt radiation for Irradiate, increase intensity, etc.

　　Quality control

　　The Quality Policy is established and structured to provide ISO 9001:2008 compliant quality management. Our quality management system is designed to provide satisfaction for our customers with defect-free products that conform to their requirements and are delivered on time.

　　We communicate our commitment to quality within the organization through the provision of resources, leadership, and quality objectives. By monitoring and reviewing the quality management system we will ensure its continual improvement and effectiveness.

chenhtbb

2021年8月18日星期三

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