China Jwell extruder machine is an auxiliary agent whose main function is to inhibit the thermal oxidative degradation of polymer resin, which belongs to the category of antioxidants. Antioxidants are the most important type of plastic stabilization additives, and almost all polymer resins involve the application of antioxidants. According to the mechanism of action, traditional antioxidant systems generally include main antioxidants, auxiliary antioxidants and heavy metal ion passivators.
The main antioxidant of Jwell extrusion machinery is to capture polymer peroxy radicals as its main function, and is also known as “peroxy radical scavenger” and “chain-terminated antioxidant”, involving aromatic amine compounds and hindered phenols Compound two series of products.
Auxiliary antioxidants have the function of decomposing polymer peroxy compounds, also known as “peroxide decomposers”, including thiodicarboxylate and phosphite compounds, and are usually used in conjunction with primary antioxidants.
Heavy metal ion passivators are commonly known as “anti-copper agents”, which can complex transition metal ions and prevent them from catalyzing the oxidative degradation reaction of polymer resins, with typical structures such as hydrazide compounds.
In recent years, with the in-depth study of polymer antioxidant theory, the classification of antioxidants has also undergone certain changes. The most prominent feature is the introduction of the concept of “carbon radical scavenger”. This free radical scavenger is different from the main antioxidants in the traditional sense. They can capture polymer alkyl radicals, which is equivalent to adding a line of defense to the traditional antioxidant system.
Such stabilizing assistants mainly include aryl benzofuranone compounds, bisphenol monoacrylate compounds, hindered amine compounds and hydroxylamine compounds, etc. The ternary antioxidant system constituted by the combination of the agent can significantly improve the antioxidant stabilization effect of plastic products.
It should be pointed out that amine antioxidants have color pollution and are mostly used in rubber products, while phenolic antioxidants and their composite antioxidant systems with auxiliary antioxidants and carbon free radical scavengers are mainly used in plastics and plastics. color rubber products.
Broadly speaking, all additives that can improve the impact resistance of rigid polymer products are collectively referred to as impact modifiers. Impact modifiers in the traditional sense are basically based on the theory of elastic toughening, and the compounds involved almost without exception belong to various copolymers and other polymers with elastic toughening effect.
As a manufacturer of extruder machines, China Jwell takes rigid PVC products as an example. Today, the varieties widely used in China extruder machine application market mainly include chlorinated polyethylene (CPE), acrylate copolymer (ACR), methacrylate— Butadiene-styrene copolymer (MBS), ethylene-vinyl acetate copolymer (EVA) and acrylonitrile-butadiene-styrene copolymer (ABS), etc. The ethylene propylene diene rubber (EPDM) used in the toughening modification of polypropylene also belongs to the scope of rubber toughening.
Most plastic products are flammable, which brings many hidden dangers to the application safety of their products. Precisely speaking, it is more appropriate to call flame retardants as flame retardants, because “flame retardant” contains two meanings of flame retardant and smoke suppression, which is more extensive than the concept of flame retardants. However, people have been accustomed to using the concept of flame retardant for a long time, so the flame retardant referred to in the literature is actually a general term for flame retardant and smoke suppression functional additives.
china extruder machine flame retardants can be divided into additive flame retardants and reactive flame retardants according to their use methods. Additive flame retardants are usually added to the base resin, and they are simply physically mixed with the resin; reactive flame retardants are generally monomers containing flame retardant elements and reactive groups in the molecule. Such as halogenated acid anhydrides, halogenated bisphenols and phosphorus-containing polyols, etc., due to their reactivity, they can be chemically bonded to the molecular chain of the resin and become part of the plastic resin. Most reactive flame retardant structures are still synthetic additive flame retardants. Monomer of the agent.
According to different chemical compositions, flame retardants can also be divided into inorganic flame retardants and organic flame retardants. Inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, antimony oxide, zinc borate and red phosphorus, etc. Organic flame retardants are mostly halogenated hydrocarbons, organic bromides, organic chlorides, phosphates, halogenated phosphates, nitrogen It is a flame retardant and nitrogen-phosphorus intumescent flame retardant. The role of smoke suppressants is to reduce the amount of smoke produced by flame retardant materials and the release of toxic and harmful gases, mostly molybdenum compounds, tin compounds and iron compounds. Although antimony oxide and zinc borate also have smoke suppression properties, they are often used as flame retardant synergists, so they are classified as flame retardant systems.
china extruder machine plasticizer is a kind of additive that increases the plasticity of polymer resin and gives the product softness. It is also the plastic additive category with the largest production and consumption so far. Plasticizers are mainly used in PVC soft products, and are also widely used in polar plastics such as cellulose.
The categories of compounds involved in plasticizers generally include phthalates, fatty dicarboxylates, trimellitates, polyesters, epoxy esters, phenyl alkyl sulfonates, phosphates, and chlorinated paraffins. , especially phthalates are the most important.
If not specified, the heat stabilizer refers specifically to the stabilizer used in the processing of polyvinyl chloride and vinyl chloride copolymers. Polyvinyl chloride and vinyl chloride copolymers are heat-sensitive resins, and they can easily release hydrogen chloride during thermal processing, thereby causing thermal aging degradation reactions. Thermal stabilizers generally achieve thermal stabilization by absorbing hydrogen chloride, replacing active chlorine, and adding double bonds.
The types of thermal stabilizers widely used in industry generally include basic lead salts, metal soaps, organic tin, organic antimony and other main stabilizers, and epoxy compounds, phosphites, polyols, and two Organic auxiliary stabilizers such as ketones. The composite stabilizer, which is composed of main stabilizer, auxiliary stabilizer and other additives, plays an important role in the heat stabilizer market.
china extruder machine light stabilizer, also known as UV stabilizer, is a kind of stabilization aid used to inhibit the photo-oxidative degradation of polymer resins and improve the weather resistance of plastic products. According to the different stabilization mechanisms, light stabilizers can be divided into light shielding agents, ultraviolet absorbers, excited state quenchers and free radical scavengers.
Most of the light shielding agents are carbon black, zinc oxide and some inorganic pigments or fillers, and their role is achieved by shielding ultraviolet rays.
Ultraviolet absorbers have a strong absorption effect on ultraviolet rays, and convert harmful light energy into harmless heat energy through intramolecular energy transfer, thereby preventing the polymer resin from absorbing ultraviolet energy and inducing photooxidation. There are many types of compounds involved in UV absorbers, mainly including benzophenone compounds, benzotriazole compounds, salicylate compounds, substituted acrylonitrile compounds and triazine compounds.
Excited state quenchers are intended to quench the energy on the excited polymer molecule, returning it to the ground state, preventing it from further causing polymer chain scission. Excited state quenchers are mostly nickel complexes.
The free radical scavenger uses hindered amine as a functional group, and its corresponding nitroxide radical is the basis for capturing polymer radicals, and because this nitroxide radical has regeneration during the stabilization process, the photostabilization effect is very prominent, So far, it has developed into the light stabilizer category with the most varieties and the largest production and consumption. Of course, the role of hindered amine light stabilizers is not limited to capturing free radicals. Studies have shown that hindered amine light stabilizers often have the functions of decomposing hydroperoxides and quenching singlet oxygen at the same time.