UPVC pipe, also known as rigid PVC pipe, is amorphous thermoplastic vinyl chloride resin by adding a certain amount of additives , and then through the extruder processing into a pipe.
You can find the following advantages for UPVC: light weight, corrosion resistance, high strength, can be recycled and so on. But is also has some disadvantages of high melt viscosity, poor mobility and other processing difficulties.
Let learn some information including raw materials, formular design and produce processing for UPVC.
In order to obtain rapid and uniform plasticization, should be used in the suspension of loose resin, resin models are SG-5.Note: S said PVC resin by the suspension method, G said general-purpose resin, SG-5 for transparent products, hard tube, profiles.
Pure PVC resin is extremely sensitive to heat, when the heating temperature reaches 90 ℃ above, it will occur a slight thermal decomposition reaction; when the temperature rose to 120 ℃ after the decomposition reaction intensified; at 150 ℃, 10 minutes, PVC resin from the original The white gradually turns yellow - red - brown - black. PVC resin decomposition process is due to the HCL reaction caused by a series of chain reaction, and finally lead to macromolecular chain breaks. One way to prevent the thermal decomposition of PVC is to add a stabilizer therein to prevent the catalytic degradation of HCl by capturing HCl produced by thermal decomposition of PVC. On UPVC pipe, usually used Lead based PVC stabilizer or calcium zinc PVC stabilizer, tin stabilizer
PVC melt adhesion metal tendency, between the melt and the friction between the melt and processing equipment, need to add lubricant to overcome the friction resistance. The amount of lubricant added is relatively small. According to the compatibility of lubricants and PVC resin different size, can be divided into internal lubricants (good compatibility) and external lubricant (poor compatibility).usually use stearic acid as internal lubricants, paraffin wax or PE wax as external lubricants
Also known as filler, filler. Add solid materials that improve performance or reduce costs in the material. usually used caco3 as filler
5.Modifier (impact modifier)
impact modifier can give PVC products with excellent impact resistance, low temperature toughness, usually use CPE and AIM as impact modifier for UPVC pipe
6. PVC processing aid
PVC processing aid is that reduce the glass temprerature of plstics,and promote PVC resin platic, improve the rheological properties of the thermoplastic melt.Mechanical properties of melt in the thermal elastic state. Improve the appearance quality of the products
usually use tio2 and carbon black as UPVC pigments
Typical UPVC Formulation recommended by shandong polymer additives:
|Acrylic processing aid||1.5|
|group of youth||0.02|
Extrusion process conditions of UPVC
Mix high speed up to 115 degrees, then put the low speed down to 45 degrees, put the material.Barrel temperature 160 ℃ ~ 180 ℃, head temperature 180 ℃ ~ 200 ℃, screw speed to see models.