PVC profiles are industrial and household PVC products made of PVC resin with various functional additives and extruded at high temperatures. In the production of PVC profiles, manufacturers are faced with the problem of choosing stabilizers. So, which stabilizers can be used in the production of PVC profiles using PVC profile production lines?
Here is the list of contents
What are stabilizers?
What are the commonly used stabilizers?
Pure PVC resin is extremely sensitive to heat, when the heating temperature reaches above 90℃, a slight thermal decomposition reaction will occur, and when the temperature rises to 120℃, the decomposition reaction will intensify. -The decomposition process of PVC resin is a series of chain reactions caused by the reaction of deHCL, which finally leads to the breakage of macromolecular chains. The mechanism of thermal stabilization to prevent thermal decomposition of PVC is achieved by the following.
Preventing the catalytic degradation of HCl by capturing the HCl generated by the thermal decomposition of PVC.
Displacing the reactive allyl chloride atom.
Reacting with free radicals and terminating their reactions.
Additive interaction with co-choked double bonds inhibits the growth of co-choked chains.
Decomposes peroxides and reduces the number of free radicals.
Passivation of metal ions with catalytic deHCl effect.
The same stabilizer can achieve the purpose of thermal stabilization according to several different mechanisms, the following stabilizers are commonly used, in actual production, manufacturers can choose according to their needs.
Lead salts
Lead salts are the most commonly used heat stabilizers in PVC profile production lines, and they are also very effective heat stabilizers, and their dosage can account for more than 70% of the heat stabilizers for PVC profiles. The advantages of lead salt stabilizers are excellent thermal stability, long-term thermal stability, excellent electrical insulation properties, good weather resistance, and low price. The disadvantages of lead salt stabilizers are poor dispersion, high toxicity, initial coloring, difficulty getting transparent products, it is also difficulty getting bright color products, lack of lubricity, easy to produce sulfur pollution.
Metal soap
Metal soaps are the second largest class of main stabilizers after lead salts, and their thermal stability is not as good as lead salts, but they both lubricities. Metal soaps can be the metal salts of fatty acids, which are most commonly used as stearates. Metal soap stabilizers are generally not used alone, often between metal soaps or with lead salts and organotin and so on. Its non-sulfurization pollution, and therefore widely used in soft PVC.
Organotin
Organotin is the most effective heat stabilizer, the most widely used in transparent and non-toxic products in a class. Its outstanding advantages are good thermal stability, good transparency, most non-toxic. Disadvantages are high price, no lubricity. Most of the organotins are liquid, only a few are solid. Can be used alone, but also often used with metal soaps. Organotin heat stabilizers mainly include sulfur-containing organotin and organotin carboxylate two categories.
Organic antimony
Organic antimony has excellent initial color phase and color phase retention, especially at low dosage, thermal stability is better than organotin, especially suitable for PVC formulations with a twin-screw extruder. Organic antimony mainly includes thiol antimony salts, thiol antimony thioglycolate, thiocarboxylate antimony, and carboxylate antimony.
In addition to the above-mentioned stabilizers, there are also rare-earth stabilizers, compound lead salt stabilizers, and auxiliary heat stabilizers, which can be used together with the PVC profile production lines to produce high-quality products. With years of production experience and advanced technology, Zhangjiagang Chenxing Machinery Co., Ltd can provide a high-quality and high-performance profile production line. And we have a professional team that can provide professional pre-sales consulting service and after-sales maintenance service. If you are interested in our products and want to get more detailed information, welcome to contact us, we are looking forward to your visit!
