At present, the plastics industry is developing rapidly and the application of plastics is becoming more and more extensive. But with the rapid development of modernization, a variety of new requirements have been put forward for plastic products. In order to meet the needs of different USES, should actively develop new synthetic resin varieties, like filler masterbatch, but also should be in the process of processing existing resin into plastic products, using chemical or physical methods to change some properties of plastic products, in order to achieve the desired purpose, which is plastic modification. Generally speaking, plastic modification technology is much easier than synthesis of a new resin, especially physical modification, in general plastic molding processing plants can be carried out, and easy to take effect, so the plastic modification work has gradually been paid attention to.
How filler masterbatch work to modify plastic
Plastic modification can be generally divided into chemical modification and physical modification. Chemical modification can be divided into graft copolymerization, block copolymerization and radiation crosslinking. Physical modification can be divided into filling modification (can also be divided into enhancement modification), blending modification, etc. There are also not according to the chemical and physical classification methods and can be divided into foaming modification, crosslinking modification tensile modification, composite modification, blending modification.
Filling modification refers to the addition of inorganic or organic filler masterbatch in the process of plastic molding, which can not only greatly reduce the price of plastic products, but also promote the promotion and application of plastic products. More importantly, it can significantly improve the mechanical properties, friction resistance, thermal properties and aging resistance of plastics. For example, it can overcome the shortcomings of plastics such as low strength, high-temperature resistance, low rigidity, easy deformation and easy creep.
Blending modification means that in the original plastic matrix or filler masterbatch, through a variety of mixing equipment (such as open refining machine, extruder, etc.) into another or several plastics or elastomers, so as to change the plastic properties. Blending plastics is also known as plastic alloy. For example, ABS(acrylonitrile-butadiene styrene copolymer) integrates the characteristics of acrylonitrile, butadiene and styrene, and its microstructure is similar to alloy.
Chemical modification is generally divided into graft copolymerization and block copolymerization. Graft copolymerization is to dissolve the parent resin in the plastic monomer to be grafted, and then polymerize the monomer to be grafted, and then graft the resin to the parent resin. Block copolymerization means that each monomer unit is connected to form a new linear molecule at its end in a certain length sequence. According to the type of monomer unit, block copolymers can be divided into diblock, triblock and multi-block copolymers.
The so-called reinforced plastics, is the polymer resin and reinforced filler (reinforcement) combined to improve the mechanical strength of an organic composite material. Glass (or carbon) fiber and its products are known as reinforcement materials, and cotton, paper, inorganic powder materials are known as filling materials or modified materials. Some general -purpose plastics can be strengthened and used as engineering plastics. For some engineering plastics, through enhancement, its performance has stepped into the category of metal strength, thus greatly expanding the depth and breadth of thermoplastics used as structural materials in the engineering field.
What is blending modification of plastics
Although modified to improve some of the properties of plastic products, but also make some of the original properties of plastic loss. For example, the addition of some fillers masterbatch will make the insulation performance of plastic, corrosion resistance, loss of some of the original luster of plastic and other problems can be based on the different USES of products, choose the appropriate formula, take appropriate measures to overcome.
Polymer blend is a mixture of two or more masterbatch. The polymer blends are mainly physically bound to each other, so the polymer blends are different from copolymers. However, in polymer blends, there is inevitably a small amount of chemical bonds between different polymer macromolecules. For example, in the melting and mixing process under the action of strong shear force, macromolecules may break due to shear action and generate macromolecules free radicals, thus forming a small number of block or graft copolymers.
In addition, reaction capacity enhancement measures adopted in recent years to enhance the interfacial adhesion between the components of blends are bound to introduce many types of polymer blends with high chemical bonds, but they generally refer to plastic-plastic blends and rubber blends in plastics. For the blending system mixed with a small amount of rubber in plastics, because of the impact performance has been greatly improved, it is commonly known as rubber toughened plastics.
Types of polymer blends, binary and multicomponent polymer blends according to the number of polymer components contained; According to the name of matrix resin in the polymer blend, it can be divided into polyolefin blend, polyvinyl chloride blend, polycarbonate blend, polyamide blend, etc. According to the performance characteristics and high-temperature resistance, low-temperature resistance, flame retardant, aging resistance and other polymer blends.
The role of filler masterbatch
Although plastic has a lot of excellent properties, but compared with metal materials, there are many shortcomings, some of the comprehensive performance requirements of high fields, a single plastic is difficult to meet the requirements. Therefore, the purpose of using filler masterbatch to blend modified plastics is as follows.
1.Improve the comprehensive properties of plastics.
2.Improve the mechanical properties of plastics, such as strength, low-temperature toughness, etc.
3.Improve the heat resistance of plastics. Most plastics do not have a high thermal deformation temperature. For some parts that work at a certain temperature, general-purpose plastics are not suitable.
4.Improve machining performance. For example, PPO is poor in molding, adding PS modified its processing liquidity greatly improved.
5.Reduce water absorption and improve dimensional stability of products. Such as polyamide water absorption is larger, resulting in product size changes.
6.Improve the burning resistance of plastics. Most plastics belong to inflammable materials, which have low safety when used in electrical and electronic equipment.
7.Reduce the cost of materials. Plastics, especially engineering plastics, are more expensive. The cost of materials is reduced and the molding property is improved by blending general plastics with engineering plastics.
8.Realize the function of plastic, improve its use performance, such as the conductivity of plastic small for some need to prevent static electricity, conductive use, can be mixed with conductive polymer, to obtain anti-static function, conductive function and electromagnetic shielding function of plastic materials, to meet the requirements of electronics, home appliances, communications, military and so on.
In short, Using filler masterbatch to blend modification, can improve the comprehensive performance of plastic, in the case of relatively low investment increase the varieties of plastic expansion of the use of plastic, reduce plastic adult cow ‘head now plastic high-performance and intensification, functionalization, specialty and seriation, promote the development of plastic industry and high polymer material industry.