Common production technology of the hottest antist

2022-08-02
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The common production technology of antistatic film

the generation of static electricity is directly related to the insulation performance of objects. Different articles have different requirements for the antistatic property of packaging film. Some goods need not only general antistatic property, but also certain conductivity. Therefore, antistatic films should be standardized and classified according to the different resistance of packaging materials. The packaging materials for electrostatic sensitive products (ESSD) specified by the International Electrotechnical Commission (1ec) are shown in Table 1, which can be used as a reference for our development and production of antistatic films

preparation of antistatic films with antistatic agents

preparation of antistatic films with antistatic agents has the obvious advantages of simple process and low price. It is the most widely used method to produce antistatic films today. At present, there are more than 100 varieties of antistatic agents that have been industrialized. Not only some famous large chemical companies abroad, such as Ciba in Switzerland and cyanate in the United States, have their own brands of antistatic agents, but also domestic chemical research institutes and institutes attach great importance to the development and research of antistatic agents, such as Shanxi Chemical Research Institute, Beijing Chemical Research Institute Hangzhou Research Institute of chemical industry has representative products of antistatic agents

we can directly mix antistatic agent into plastic particles (or powder) after measurement to produce antistatic film; The antistatic agent can also be mixed with other ingredients to make master batch. When making plastic film, the master batch is mixed into the plastic particles, and the antistatic film is produced according to the conventional film-forming method that the person in charge frankly stated. The process is convenient and easy. According to the actual needs of the production of antistatic films, some necessary additives can be added to improve the performance of the products (for example, adding opening agent to reduce the viscosity of the films), so as to simplify the development and research of antistatic films into the development and research of antistatic master materials; At present, most of the domestic manufacturers of functional masterbatch have brand-name antistatic masterbatch products. Therefore, for units with relatively weak increasing demand in the international market, they can choose antistatic masterbatch with excellent performance from specialized enterprises producing antistatic masterbatch to complete the development of antistatic film. Therefore, it is a desirable method to use antistatic masterbatch to produce antistatic films, whether in enterprises with strong technical force or in units with weak technical force, to strengthen the processing capacity of experimental data information

two problems should be paid attention to when producing antistatic films by using internal antistatic electrocution: one is that the antistatic agent has a process of diffusion from the plastic matrix to the surface of the film, so it does not show antistatic property after the film is just formed. After a period of storage, the antistatic property gradually increases before reaching an extreme value (determined by the balance value between the variety and dosage of antistatic agent), and the other is to reach a given value, The amount of internal antistatic agent is related to the thickness of the film. The thinner the film, the more antistatic agent needs to be added. The decrease of antistatic properties of antistatic films produced with surfactant antistatic agents is mainly due to the decrease of surface resistance, which is generally not less than 108 Ω. Therefore, the antistatic effect is limited. It is not enough for some areas with high antistatic requirements, such as the packaging of integrated circuits and large-scale integrated circuits

the antistatic properties of the antistatic films produced with surfactants are obviously affected by the environmental humidity. When the humidity is low, the antistatic properties of the films are low. When the atmospheric humidity is lower than 25%, they basically lose their practical use value. In addition, the internal antistatic agent produces the antistatic effect by diffusing to the surface of the film. When used, it exists on the surface of the film, and the antistatic agent is easy to cause. The loss due to friction, water washing and other reasons is often unsatisfactory in terms of durability (as the lost antistatic agent can be supplemented by the diffusion of the antistatic agent inside the film to the film surface, it generally has better durability than the antistatic film produced with external antistatic agent)

using conductive fillers to produce antistatic plastic films

using conductive fillers can not only produce antistatic plastic films, but also because its antistatic property is based on the conductivity of fillers, its durability is better than that of surfactant type antistatic and it should be elastic and suitable for films, and its antistatic property is less affected by environmental humidity. Carbon black filled antistatic materials are the most widely studied and applied in filled antistatic packaging plastics. Its performance mainly depends on the type, framework structure, dispersion performance, surface state, addition concentration, etc. of conductive fillers, as well as the type and structure of plastic materials and the process method of filler addition. Acetylene black and high-temperature graphitized carbon black have stable structure, are not easy to oxidize, and are easy to form extended chain or like structures in polymers, which can obtain excellent antistatic properties. In order to improve the antistatic performance of carbon black system, it is often mixed with metal oxides, elastomers and other substances. For example, carbon black and inert fillers such as clay and talc powder form binary fillers, which can reduce the resistivity by an order of magnitude. Conductive materials with volume resistance of 10-1 Ω· cm ~ 105 Ω· cm can be prepared by using carbon black and clay binary fillers. The two limitations of carbon black antistatic films are that they are opaque and can only be used as black films

metal oxide filled antistatic material is a new product developed in recent years. Its performance is slightly worse than that of metal filled material, but its cost performance is good. At present, titanium oxide and zinc oxide have been successfully applied, among which tin oxide has good performance and price. Its color phase is light and its particle size is very small (below 0.1pm), which can meet the requirements of transparency and anti-static. According to the conductivity theory, the shape of the filler tends to be flat from spherical, and its conductivity increases. Therefore, Japan has successfully developed a new conductive mica sheet filler in recent years. A layer of conductive metal oxide is deposited by the solid solution method. On the surface of smooth mica sheet powder, a layer of sn02 is deposited by the solid solution method to make a novel conductive MEC. The appearance is gray white and has transparency. The volume resistivity can reach the order of 10 Ω· cm, and the transparency of the coating can reach more than 80%

producing anti-static film with coating

producing anti-static film with coating is different from producing anti-static film with external anti-static agent. The coating type anti-static technology does not use the solution of surface anti-static agent to coat the surface of the film, but uses conductive coating material to coat the plastic surface to form a uniform coating, so as to endow the plastic with conductivity and make it an anti-static material, In principle, this method can also be used to manufacture antistatic films

in the past 10 years, conductive coatings belonging to the field of coating industry have developed rapidly, with increasing performance and types, and formed a series of conductive coatings:

① antistatic carbon coatings, which mainly use carbon black as the conductive component, have the advantages of excellent performance and low price, and are now widely used

② electrostatic metallic coatings, the conductive components are mainly flake aluminum, nickel and copper

③ in anti-static metal oxide coatings, powdered tin oxide, zinc oxide, titanium oxide, indium oxide, cadmium oxide and other micro powders such as sbcl8, snc14, sn02 and Sb2O5 are mainly used

the above conductive components and acrylic resin form a new anti-static coating. In recent years, antistatic film-forming materials have been developed continuously. For example, the charge transfer polymer complex solution is used to coat the plastic to obtain good antistatic, or the charge transfer complex solution composed of antimony pentachloride and polyvinylcarbazole is used to coat the polyethylene plastic products

antistatic film produced by surface modification

this is a new kind of antistatic packaging material. When conducting graft copolymerization, the mixture containing monomers is first irradiated with rays to obtain good antistatic properties. As used in recent years β X-ray irradiated acrylic acid or methacrylic acid is grafted onto polyethylene or polypropylene; The antistatic properties of polyamide grafted with methacrylic acid can be significantly improved by irradiating polyamide with butyl ray. Acrylic acid, acrylamide, vinyl-3-ethoxysilane and their mixtures can be grafted onto poly (tetrachloroethylene) by irradiating with 60Co source Ya ray while heating. The plastic film has obvious antistatic effect; Using electron beam and laser to treat polymer lining can also obtain excellent anti-static function. The packaging bags treated by electron beam in the United States have been put on the market. They have good durability, no corrosion, no pollution, and excellent performance. They can be comparable with antistatic Jing type and carbon black filled antistatic materials. They have shown the momentum of participating in market competition

the method of producing antistatic film by electron beam treatment can also be used in transparent composite flexible packaging materials (bags), which is undoubtedly a new development direction of antistatic. The transparent products produced by this method have been sold on the market. The coating type antistatic film and composite antistatic film produced by evaporation technology form a conductive metal coating on the surface of polymer materials, such as physical vapor deposition (PVD), chemical vapor deposition (CVD) and other process methods, which can also be used to produce antistatic films. Vacuum physical vapor deposition (vpcvd) is a new technology in the ascendant. It mainly includes vacuum evaporation, sputtering and ion plating. The vacuum aluminized film and aluminized paper that have been widely used in the packaging industry are the products of this technology. Vacuum physical vapor deposition usually heats the metal aluminum above the melting point in a vacuum of 10MPa ~ 10MPa to form aluminum vapor, which finally condenses on the surface of plastic materials to form a very thin metal aluminum film. Vacuum physical vapor deposition can also evaporate other metals and metal oxides

composite packaging material is also a practical anti-static packaging technology. Generally speaking, anti-static packaging not only requires the materials to have certain anti-static functions, but also should have physical, mechanical, chemical and comprehensive technical and economic properties such as durability, heat resistance, light resistance, pressure resistance, chemical crystal resistance, economy and safety. One of the best implementation schemes is to adopt composite technology. Composite anti-static packaging plastics have been widely used as packaging bags (containers). Its structural characteristics are that there are often 3-4 layers of barrier shielding layers (these shielding layers mainly use metallized films and films filled with conductive fillers), and the most surface and innermost layers generally use anti-static films in the form of anti-static agents, which is the popular mainstream now and the development direction of anti-static packaging bags in the future. In addition, the use of resin with low resistance value is also an industrialized method to obtain antistatic films. For example, the polyvinyl alcohol film produced mainly by polyvinyl alcohol resin with low resistance value is an antistatic film with good performance (the surface resistance is about 108 ohms). In Japan, polyvinyl alcohol film is widely used in the sales and packaging of commodities such as textiles and clothing (with an annual consumption of more than 10000 tons). Compared with general-purpose films such as polyethylene and polypropylene, polyvinyl alcohol film can significantly reduce the dust absorption effect and improve the display effect of commodities. (end)

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