Common production technology of antistatic film

2022-05-28
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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 need to 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 film with antistatic agent

preparation of antistatic film with antistatic agent has the obvious advantages of simple process and low price. It is the most widely used method to produce antistatic film today. At present, there are more than 100 varieties of industrialized antistatic agents. 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 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 combined with other components to make master batch. When manufacturing plastic film, the master batch is mixed into plastic particles and formed into film according to the conventional method. The person in charge frankly said that the antistatic film is produced. The process is convenient and easy. According to the actual needs of the production of antistatic film, some necessary additives can be added to improve the performance of the product (for example, adding opening agent to reduce the viscosity of the film), so as to simplify the development and research of antistatic film into the development and research of antistatic master material; At present, most of the domestic manufacturers of functional masterbatch have brand-name antistatic masterbatch products. Therefore, for units with relatively weak demand in the international market with gradually increasing technical power, they can choose antistatic masterbatch with excellent performance from specialized enterprises producing antistatic masterbatch to complete the development of antistatic film. Therefore, whether to strengthen the processing capacity of experimental data and information in enterprises with strong technical force or units with weak technical force, it is a desirable method to use antistatic masterbatch to produce antistatic film

two problems need to be paid attention to when producing antistatic films by using internal antistatic electrocution: one is that the antistatic agent has a diffusion process from the plastic matrix to the film surface, so it does not show antistatic property after just forming the film. After a period of storage, the antistatic property gradually increases, and finally reaches an extreme value (determined by the balance value between the variety and dosage of antistatic agent). 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 is, the more antistatic agent needs to be added. The decrease of antistatic property of antistatic film produced by surfactant antistatic agent mainly comes from the decrease of surface resistance, and the decrease of surface resistance is limited, which is generally not less than 108 Ω. Therefore, the antistatic effect is limited, and 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 property of the antistatic film produced by surfactant antistatic agent is obviously affected by the environmental humidity. When the humidity is low, the antistatic property of the film is low. When the atmospheric humidity is lower than 25%, it basically loses the actual use value. In addition, the internal antistatic agent produces 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 be used. The loss due to friction, water washing and other reasons is often unsatisfactory in terms of durability (because 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 filler to produce antistatic plastic film

using conductive filler can not only produce antistatic plastic film, but also because its antistatic property is based on the conductivity of filler, its durability is better than that of surfactant antistatic film, 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, skeleton structure, dispersion performance, surface state and addition concentration of conductive filler, 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 can reduce the resistivity by one 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 major 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 relatively 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 solid solution method. On the surface of smooth mica sheet powder, a layer of sn02 is deposited by solid solution to make a novel conductive MEC, which is gray white in appearance and has transparency. The volume resistivity can reach the order of 10 Ω· cm, and the transmittance of the coating is more than 80%

producing anti-static film with coating

producing anti-static film with coating is different from producing anti-static film with external antistatic agent. Coating anti-static technology does not use the solution of surface antistatic 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 give the plastic conductivity and make it an anti-static material, In principle, this method can also be used to manufacture antistatic films

in recent 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 conductive component, have the advantages of excellent performance and low price, and are widely used now

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 are prepared into a new anti-static coating. In recent years, antistatic film-forming materials have been developing continuously. For example, coating plastics with charge transfer polymer complex solution to obtain good antistatic, or coating polyethylene plastic products with charge transfer complex solution composed of antimony pentachloride and polyvinylcarbazole

antistatic film produced by surface modification

this is a new kind of antistatic packaging material. During the graft copolymerization, the mixture containing monomers is irradiated with rays to obtain good antistatic properties. If used in recent years β Acrylic acid or methacrylic acid treated by X-ray irradiation and then grafted onto polyethylene or polypropylene; When polyamide is irradiated with butyl ray and then grafted with methacrylic acid, their antistatic properties can be significantly improved. When heated and irradiated with ya ray of 60Co source, acrylic acid, acrylamide, vinyl-3-ethoxysilane and their mixtures are grafted onto polytetrachloroethylene, and the plastic film has obvious antistatic effect; The excellent anti-static function can also be obtained by treating the polymer lining with electron beam and laser. The packaging bag treated with electron beam in the United States has been put on the market. It has good durability, no corrosion, no pollution and excellent performance. It can be comparable with antistatic Jing type and carbon black filled antistatic materials. It has 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 put 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. Process methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD) can also be used to produce antistatic films. Vacuum physical vapor deposition is a new technology in the ascendant. It mainly includes vacuum evaporation plating, sputtering plating and ion plating. Vacuum aluminized film and aluminized paper, which 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 an extremely thin metal aluminum film. Vacuum physical vapor deposition can also evaporate other metals and metal oxides

composite packaging material is also a practical antistatic packaging technology. Generally speaking, anti-static packaging not only requires materials to have certain anti-static functions, but also should have physical, mechanical and chemical properties such as durability, heat resistance, light resistance, pressure resistance, chemical crystal resistance, economy and safety, as well as comprehensive technical and economic performance. One of the best implementation schemes is to adopt composite technology. Composite antistatic packaging plastics have been widely used as packaging bags (containers). Its structural feature is that there are often three to four layers of barrier shielding layers in the middle (these shielding layers mainly use metallized films and films filled with conductive fillers). The antistatic film of antistatic dosage form is generally used in the outermost layer and innermost layer, which is the popular mainstream and the development direction of antistatic packaging bags in the future. In addition, using resin with low resistance value is also an industrialized method to obtain antistatic film. 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 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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