Views: 30 Author: Site Editor Publish Time: 2020-02-01 Origin: Site
PVC pipe fittings have the advantages of good appearance quality, high impact toughness and good water pressure resistance, and their comprehensive performance is superior to ordinary pipe fittings. Below are some of the design contents of PVC pipe fittings and some materials used.
PVC pipe fitting design ideas
Materials used in PVC pipe fitting formulations
summary
The processing stability of PVC pipe fittings is not good, the melting temperature (160 °C) is higher than the decomposition temperature (140 °C), the melt viscosity is high, and the fluidity is poor (even if the injection pressure and melt temperature are increased, the fluidity changes little) It is difficult to form (the molding temperature is very close to the thermal decomposition temperature, and the temperature range in which molding can be performed is narrow), and it is difficult to process by melt plasticization without modification. One of the methods of modification is to add a stabilizer thereto to increase the decomposition temperature above the melting temperature. The second is to add a plasticizer to reduce its melting temperature below the decomposition temperature.
l stabilizer
Principle of action: The salt-based lead salt inhibits its autocatalysis by capturing the detached hydrogen chloride.
1. Tribasic lead sulfate, white or slightly yellow powder. It is discolored in daylight, sweet and toxic! Do not dissolve in water, soluble in hot acetic acid amine solution. Unstable can decompose on its own. Must be stored, melting point 820 °C, excellent thermal stability and electrical properties. Main PVC stabilizer for long-lasting stability.
2. Dibasic lead phosphite, white or yellowish powder, sweet. The relative density is 6.94. The refractive index is 2.25. Soluble in hydrochloric acid, nitric acid, ammonium acetate solution insoluble in water and organic solvents.
l Plasticizer
DOP Dioctyl phthalate: good compatibility, good light stability, good electrical insulation, low temperature resistance, non-toxic, colorless oily liquid.
l Auxiliary plasticizer
Epoxidized soybean oil is a light yellow viscous oily liquid at room temperature. It is one of the most widely used non-toxic plasticizers for PVC and a stabilizer. It can impart good mechanical strength, weather resistance and electrical properties to the product, and is non-toxic. It is an internationally recognized chemical processing aid for food packaging materials. Can be used on all PVC pipe fittings.
l Lubricant
1. Metal soap: a metal salt of a higher fatty acid, which is one of the commonly used lubricants. In addition to lubrication, it is also a heat stabilizer for PVC. For a saponified product of a certain metal, the longer the carbon chain of the bound fatty acid, the better the lubricity. Commonly used are calcium stearate, zinc stearate, lead stearate, etc., of which lead stearate has the best lubricity.
2. polyethylene wax: also known as polymer wax, as a lubricant, its chemical properties are stable, electrical properties are good. Polyethylene wax has a stronger internal lubrication than other external lubricants for PVC.
l Filler
1. Chlorinated polyethylene CPE: [CH2-CHC1-CH2-CH2]n, saturated polymer material.
2.light calcium carbonate CaCO3: non-toxic, odorless, non-irritating, usually white. Calcium carbonate can play a skeleton role in plastic products, which has a great effect on the dimensional stability of plastic products, can improve the hardness of the products, and can also improve the surface gloss and surface flatness of the products. The addition of calcium carbonate in general plastic products can improve the heat resistance. Since the whiteness of calcium carbonate is above 90%, it can also replace the expensive white pigment to play a certain whitening effect on PVC pipe fittings.
l Modifier
ACR: Acrylate copolymer with core-shell structure, is a PVC impact modification with excellent comprehensive properties.
Our company specializes in the production of PVC pipe fittings. Our PVC pipe fittings are all in compliance with the standard and you can use them with confidence. If you have any questions, you can contact us!
