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Dongguan pc lens---PVC transparent hose formula composition

by:Eugenia     2022-01-10
PVC transparent hose is made by adding a large amount of plasticizer, a certain amount of stabilizer and other additives to polyvinyl chloride resin, and then extrusion molding. It has the characteristics of transparency and smoothness, light weight, beautiful appearance, flexibility and good coloring. It is widely used in construction, chemical industry, households, for water infusion, transporting corrosive media, and also used as wire casing and wire insulation layer. The formula of PVC transparent hose mainly includes: PVC resin, heat stabilizer, lubricant, plasticizer and coloring agent. According to the analysis of the above technical indicators, the formulation design should meet the requirements of transparency, moderate hardness, and high strength. In order to improve transparency, when selecting processing accessories, try to choose additives with the same or similar refractive index as the refractive index of PVC resin (1.52~1.55). Because raw materials with the same or similar refractive index are processed into a uniform mixture, their refractive index is also similar to that of the raw material. In this way, the scattering phenomenon in the direction of the incident light will not increase, so the turbidity of the product will not increase, and the transparency of the product will not be affected too much. PVC resin: Due to the relatively large amount of plasticizer in the formula, PVC resin is required to have good oil absorption, and loose resin should be selected. At the same time, the resin is required to have high whiteness and good thermal stability. Batches with fewer impurities and fisheyes. On the premise of meeting the mechanical performance requirements, the production of PVC transparent hose should try to use resin with a slightly lower molecular weight. Because the commonly used plasticizers DOP and DBP often contain low molecular weight components, when the processing temperature is higher than 105 ℃, they will often volatilize to form bubbles, and the temperature can only be controlled at a low level. In this case, resins with low molecular weight have a higher degree of plasticization and melting than resins with large molecular weights, which is beneficial to improve the transparency of products. In addition, resins with a slightly lower molecular weight are also easy to process. Generally, PVC-SG3, SG4 and SG5 resins are available, and can be selected according to product requirements. Plasticizer: Mainly consider its plasticizing effect, cold resistance, durability and impact on the transparency of PVC. DOP is a plasticizer with better comprehensive performance, with a refractive index of 1.484, which is close to the refractive index of PVC (1.52~1.55). It is often used as the main plasticizer for PVC transparent hoses. The refractive index of DBP is 1.492, which is also close to the refractive index of PVC resin. It will not affect the transparency too much, but its speed-increasing efficiency is poor and it is volatile. It is generally used as a DOP auxiliary plasticizer. To improve cold resistance, DOS can be added as a secondary plasticizer. The amount of plasticizer is generally 40 to 55 parts. Heat stabilizer: In addition to the basic properties such as heat resistance, weather resistance and ease of processing, the transparency should also be considered. Organotin stabilizers are the most ideal and commonly used heat stabilizers for PVC transparent products, but they are relatively expensive. Metal soap stabilizers, such as calcium stearate, barium stearate, zinc stearate, etc., are all commonly used heat stabilizers for PVC transparent hoses. Its composite products Ca/ Zn, Ba/ Zn, Ba/ Ca and Ba/ Ca/ Zn are more ideal. In the actual formula, in order to reduce the amount of organotin, calcium stearate (calcium soap) and zinc stearate (zinc soap) with good transparency and lubricating effect are used as auxiliary stabilizers. Antioxidant phosphite and epoxidized soybean oil with plasticizing and thermal stability, good transparency, low price, can reduce the amount of organotin, have a good effect on reducing the coloring in the later stage of the processing, and are combined with hard Calcium stearate and zinc stearate have a synergistic effect and contribute positively to the stability of the formulation system. Lubricant: It can be divided into internal and external lubricants. In the PVC transparent hose, due to the large amount of plasticizer, the viscosity of the material is relatively small, and the fluidity is good, so the amount of lubricant is small, the amount is 0.1~1.0 parts. Metal soaps are generally used, such as CaSt, BaSt, ZnSt, PbSt (the amount of PbSt is controlled at about 0.1 part, if the amount is too much, it will affect the transparency of the product) and so on. Actually commonly used transparent lubricants are: paraffin wax, polyethylene wax, stearic acid, stearic acid ester and so on. Coloring agent: More objectively speaking, it should be a complementary coloring agent. Due to the particularity of the molecular structure of PVC, the effect of heat and mechanical friction during processing, even if sufficient stabilizers are added, it will turn yellow to a certain extent. Adding a little pigment can hide the yellow color and make the product more beautiful. Commonly used colorants include ultramarine blue, phthalocyanine blue, and brighteners. Dongguan pc lens
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