Application of Nano-ATO Powder in Polymer Antistatic Packaging Materials

Abstract : This paper summarizes the research progress of the application of nano- ATO conductive powders in polymer antistatic materials from anti-static coatings, anti-static fibers and anti-static plastics, and points out several issues that need further study.

Keywords: nano- ATO antistatic application

The product needs packaging, and the quality of the packaging material directly or indirectly affects the quality of the product. In the past, most of the product packaging focused on its appearance, moisture, heat insulation, thermal insulation and other properties, but did not pay enough attention to anti-static, anti-RF performance, but also caused serious consequences, it is reported that the world's electronics industry due to electrostatic discharge The losses caused by (EDS) amount to tens of billions of dollars per year. ” In recent years, with the development of materials science, polymer materials have been widely used in packaging and other fields because of their superior performance in production, processing, and use. Research on antistatic materials has also become one of the hot topics at home and abroad.

Antistatic polymer materials commonly used method is to add a conductive filler material, the conventional conductive fillers exposed many problems in the course of ': Precious metal filler (e.g., gold powder, silver powder, nickel powder) good conductivity, However, it is expensive and not suitable for large-scale use;copper powder is inexpensive, but it is easily oxidized;carbonaceous fillers have good electrical conductivity and their use is limited in their endurance.For this reason, foreign countries developed cheap and light colors in the 1990s . The metal oxide conductive filler has been rapidly developed. Antimony Doped Tin Oxide ( ATO) is an N -type semiconductor material and the nano ATO conductive powder is compared with the conventional antistatic material. Has obvious advantages, mainly in the good conductivity, light-colored transparency, good weatherability and stability, and low infrared emissivity, etc. ) : surface, is a new multi-functional conductive material with great development potential " . From the three aspects antistatic coating, antistatic fiber and anti-static plastic powder introduced nano ATO Application polymer antistatic material.

1 Antistatic coating

Antistatic coatings are the main market for nano- ATO powders. The nano- ATO powder is added as a conductive filler to a matrix resin such as a polyamide or an acrylic, and an appropriate dispersion method is selected to prepare a nano-composite transparent antistatic coating. In the nano- ATO composite antistatic coating, when the addition amount of nano- ATO powder reaches a certain critical value, the electrical conductivity of the coating is significantly improved. Studies have shown that the critical volumetric concentration (CPVC) of the nano- ATO powder is approximately 23 % in the coating. After the PVC reaches 23 %, the coating has good conductivity, as shown in FIG. 1 . However, further increasing the amount of nano- ATO does not help the improvement of the conductive properties of the coating. On the contrary, it will affect the color, transparency and mechanical properties of the coating. In addition, the type of matrix resin, the amount of solvent, and the preparation process all have a significant effect on the properties of the coating.

Due to the large specific surface area and high specific surface energy of nano- ATO particles, it is a thermally unstable system, and the powder particles spontaneously aggregate with each other to reduce the enthalpy of the entire system. This formation of agglomerated secondary particles, or even tertiary particles, will destroy the ultrafineness and uniformity of the end, affect the performance of the nanopowder, and then affect the final use performance of the product.1 ) Therefore, the antistatic properties of the coating are affected. The primary factor is the high dispersion of nano- ATO powder.

For the problem of how to achieve high dispersion of nano- ATO powder in transparent conductive coatings, Li Qingshan et al. [2 ] studied the formation conditions of highly dispersed nano- ATO powders prepared by co-precipitation in water, and discussed the milling time and the value of PH on dispersion. The influence of the system shows that, without any additives, the ball milling time needs more than 5 days to form a nano- ATO powder-water dispersion system with good dispersion effect; the nano- ATO powder has strong alkali and isoelectric point (pH= an aqueous solution 1.8) near the coagulation, and away from the isoelectric point (PH value of 10-11 in an aqueous solution. 5) may exhibit different dispersion state, the state of agglomeration can be formed without antimony-doped high stability Tin dioxide superfine powder water dispersion system. Wang Dong et al. "" studied the stability and dispersion behavior of nano- ATO in water, and discussed the effects of the type of dispersant, the amount of ATO , the pH , and the amount of dispersant on the stability, dispersibility and rheological properties of the system. The viscosity was low. Stable dispersion J , Wow good nano ATO suspension.

Nano- ATO composite anti-static coating is a versatile functional material, such as transparent packaging film antistatic coating for electronic devices, flat display materials, surface heating elements, etc. In addition, different blue tones can be obtained by adjusting the doping amount of tellurium. The nano- ATO powder, thus obtaining anti-static coatings of different shades, is crucial for its application in the packaging field.

2 antistatic fiber

Nano-inorganic powder modified fiber materials are gradually becoming an important development direction of fiber material modification. Compared with other types of anti-static fibers, nano-sized metal oxide antistatic fibers have many unique and outstanding properties, such as being free from the limitations of the climate and the use of the environment, the stability is good; nano-scale metal oxides are not easy to fiber Shedding, even distribution; fiber preparation process is simple; a wide range of fiber use, almost any occasion to use anti-static dry, etc. " . New nano-transparent conductive powder, prepared for its transparency and excellent conductivity It is popular among people that there are three main ways to use nano- ATO for antistatic treatment of chemical fiber:

1) The nano-sized ATO powder is directly added during fiber spinning. The key is the compatibility of the inorganic nano-sized ATO with the fiber material, and it is necessary to add a special dispersing aid;

2) adding nanoscale ATO or its aqueous suspension during the dyeing process of raw materials ( such as wool and polyester yarn ) , so that dyeing and functionalization can be completed in one step;

3) Add a nano-sized ATO aqueous suspension during the dyeing or finishing process of the grey fabric.

Wang Dong and others from Donghua University's State Key Laboratory of Fiber Modification used nano powder ATO powder as an antistatic agent and polyethylene imine (PEl) as a dispersant to stably disperse nano ATO in deionized water. For the first time, the suspension is used as a preheating bath for the polyacrylonitrile fiber spinning process to improve the antistatic properties of the PAN fiber. Due to the difference in concentration of nano-inorganic microparticles inside and outside the fiber and the presence of a large number of micropores in the primary PAN fibers, the nano- ATO microparticles can diffuse into the fiber or adsorb to the surface of the fiber. When the PAN fiber is stretched, dried, and densified, The nano- ATO can stay in the fiber and form a conductive channel in which the nano- ATO locally contacts, giving the PAN fiber anti-static properties. The experimental results show that the volume resistivity of the nano- ATO modified PAN fiber is reduced by three orders of magnitude, has good antistatic properties, and also maintains the original mechanical properties of the fiber. In addition, the National Engineering Research Center for Ultrafine Powders is also developing the application of nano- ATO in the preparation of anti-static fibers and other fields.

At present, the most important method to improve the electrostatic properties of polyester fabrics is to use organic antistatic agents to perform antistatic finishing through simple and easy fabric finishing techniques. However, due to the existence of organic antistatic agents that have a large dependence on the environment humidity and poor durability of antistatic effects, the search for an antistatic agent with excellent and durable antistatic properties has become a research hotspot. Wu Yue and others Emi used nano- ATO powders for antistatic treatment of polyester fabrics. The experimental results showed that the surface resistance of polyester fabrics treated with nano- ATO antistatic finishing agents was reduced from untreated >1012Ω to <1010Ω , and washed 50 times. The antistatic effect is basically unchanged. Chen Xuelai et al. "" applied a coating method to the antistatic function of nanoscale ATO antistatic agents on polyester fabrics. The experimental results showed that only when ATO particles were exposed on the surface of the film could it exert antistatic properties; when ATO Partial annihilation of the particles in the film and partial exposure to the surface of the film exist in the coating, the antistatic properties of the coating film last. Ding Zhongfu et al. used nano- ATO powder with different germanium doping content for the antistatic treatment of polyester knitted fabrics. Studies have shown that the doping amount of the powder is one of the main factors affecting the antistatic performance, and the doping amount is 4 % to 8 %. Within the scope of the quantity test, the more the doping amount, the better its antistatic performance, but the color of the powder will also deepen, which will affect its use on light-colored textiles.

Functionalization of fibers is an important development trend for synthetic fibers. China is a big country in the production and consumption of chemical fiber. Antistatic treatment of chemical fiber will be one of the important markets for nano- ATO powder.

3 Antistatic plastic

At present, various inorganic conductive fillers ( such as copper powder, silver powder, carbon black, etc. ) are incorporated into the matrix polymer to form the most useful antistatic polymer material, and the volume resistivity of the composite material is within a relatively large range. Adjustable, many of which have been commercialized abroad. However, due to poor dispersion material such as carbon black in plastics, J compatibility with plastics, wow bad, and therefore it is also subject to certain restrictions on the application. The nano- ATO powder has a small particle size, has good compatibility with plastics, and has a light color, thereby broadening the field of application of conductive powder on plastics. The main problem to be solved in the application of nano- ATO powder in the antistatic process of plastic surface is the relationship between the amount of material added and mechanical mechanical properties of the material, and the dispersion of nanometer powder in the matrix resin, for example, skin core structure and multi-layer can be used. Extrusion and other special processes, which require the preparation of nano- ATO conductive plastic masterbatch.

4 knot   language

Nano- ATO powder has significant advantages compared with traditional anti-static materials, and has a broad application prospect in the field of anti-static polymer materials, and has great potential for development. How to develop and make use of these advantages of nano- ATO to make it a firm foothold in the market, the following aspects of the work needs further in-depth study.

1) Reunion of nano- ATO powders. From the current level of preparation, no matter which method the powder prepared, the particles tend to gather together to form secondary particles, or even tertiary particles, greatly affecting the performance of the nano-powder. Therefore, we must start from the agglomeration mechanism and explore a practical and feasible solution to the agglomeration of nanopowders during their preparation and storage.

2) There are many reports on the preparation methods of nano- ATO powders, but most of them are in the laboratory sample preparation level. There are not many methods for realizing industrial mass production, and efforts must be made to explore the best preparation methods and engineering amplification techniques.

3) Actively explore the new application areas of nano- ATO powders and contribute to improving people's living standards.