Antioxidants are a class of chemicals that, when present in only a small amount in a polymer system, can delay or inhibit the oxidation process of the polymer, thus Preventing the aging of polymers and extending their service life, they are also called “anti-aging agents”
In the plastics industry, antioxidants, as a plastic additive, are one of the most widely used additives in plastics. 1. Appropriate selection and use can effectively inhibit or reduce the thermal oxidation reaction speed of polymer macromolecules, delay the thermal and oxygen degradation process of materials, extend the service life of plastic products, and improve the use value of plastic products.
Classification of antioxidants added to plastics:
According to the understanding of antioxidant suppliers: the classification of antioxidants, one is the main antioxidant Agent: Capture oxidative free radicals, mainly hindered phenol antioxidants; main anti-sterically hindered phenols, Antioxidant 1010, Antioxidant 1076 belong to this category, long-term sustainability by capturing free radicals generated during the degradation process of plastics Act as an antioxidant.
One is an auxiliary antioxidant: it decomposes hydroperoxides, mainly phosphites and thioesters. Auxiliary antioxidants – phosphites and thioesters. Antioxidant 168 is a phosphite auxiliary antioxidant. It achieves antioxidant purposes by decomposing peroxides produced by further degradation of plastics. It mainly provides thermal processing stability; main Using resistance + auxiliary resistance together can produce a synergistic effect.
At present, in the plastics industry, there are two main ways to add and use antioxidants, the direct addition of additives and the masterbatch addition:
The direct addition method of additives is to directly mix anti-aging additives (powder or liquid) with resin and other raw materials, then extrusion granulation or injection molding, etc. Because this addition method is simple and easy to implement, it is widely used by the majority of pelletizing and injection molding factories. However, it also has some fatal shortcomings. Especially in polymer thin products or spinning products, anti-aging additives are directly mixed with other raw materials such as resin, which often makes the additives unable to achieve a good dispersion effect in the product. It is easy to cause problems such as “crystal points” in the film or “breakage” in the fibers, which affects the normal production and reduces production efficiency, and leads to a reduction in its anti-aging performance.
The masterbatch addition method is to first use a suitable resin as a carrier, mix it with a variety of highly efficient anti-aging additives, and then co-extrude and granulate it through a twin-screw extruder to obtain the anti-aging masterbatch. It is directly mixed with resin and other raw materials and then extruded for granulation or injection molding. The advantage of its application is that the anti-aging additives are first pre-dispersed during the preparation process of the masterbatch, and then during the later material processing, the anti-aging additives are secondary dispersed, so that the additives are evenly dispersed in the polymer material matrix. The purpose is not only to ensure the quality stability of the product, but also to avoid dust pollution during production, making the production more green and environmentally friendly.
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