Science Papers - Conductive Coatings

Conductive coatings have been developed for about half a century. The first open conductive coating was in 1948, when the United States patented silver and epoxy resins as conductive gels. In the 1950s, China also began to study and apply conductive coatings

. In recent decades, conductive coatings have been
in various military and civil industries such as electronics, electrical appliances, aviation,
printing.
, the theoretical research of conductive coatings has been developed rapidly and promoted the increasing maturity and perfection of applied technology. According to the classification of application materials, conductive materials can be divided into
-type conductive coatings
and
doped conductive coatings
.
-type conductive coating refers to
a conductive coating made from a conductive polymer of this type as a film-forming substance
. This type of conductive coating is mainly used
anti-corrosion anti-static coating, absorbent coating, electromagnetic shielding coating
etc.
-doped conductive coating refers to the addition of conductive substances based on polymer polymers, using the conductive effect of conductive substances. Commonly used conductive fillers are
metal fillers, carbon fillers, metal oxides fillers, composite fillers, new nano-conductive fillers
etc. Because doped conductive coatings are cheap and simple, they are widely used.
e.g. anti-static epoxy self-leveling, anti-static oil tanks, aluminum profiles, steel cabinets, shelves, workstations, (Huawei, Foxconn) new plant, mine ventilation pipes and other fields. Such as
Aksu, Libang, Tiger, Huajia, Wan'an, Huaguang, Xiangsheng, Wise (aluminum profile), Luoyang Leka (steel cabinet), Tianjin Ruiyuan (anti-corrosion)
and other industries on behalf of enterprises, relatively large-scale, technical research and development capabilities of enterprises, technical reserves will involve conductive coatings or anti-static coatings such a subdivided functional powder.
addition, conductive coatings can be divided according to the characteristics of the application: the conductive body of the paint, radiation shielding coatings,
anti-static coatings
and so on.
out of the importance of anti-static coatings, the next small interesting specific to introduce anti-static coatings.
29, 2019, a fire broke out in Ningbo Ritchie Daily Products Co., Ltd. The
killed 19 people and injured three others,
area of the fire was about 1100m2. The accident investigation team investigation determined that the direct cause of the accident is that when The Company employee Sun Azong poured the heated isomer alkane mixture into a plastic bucket,
due to electrostation discharge caused a combustible vapor fire

the dangers of static electricity are obvious to all. According to incomplete statistics, in recent years, China's petrochemical enterprises have had a number of static accidents, losses of hundreds of millions of dollars. Even in life, static electricity-induced fires are everywhere.
static electricity can be generated at any time, anywhere people live. In industrial production, static electricity can cause electromagnetic interference, causing the failure or wrong action of electronic equipment, in the production, storage place and equipment of flammable and explosive products or dust, oil mist, equipment can easily cause explosion and fire, and other hazards that are not conducive to production operations and affect product quality.
it is almost impossible to completely eliminate static electricity, but some measures can be taken to control static electricity so that it does not cause harm. For example:
the use of conductive electrostitive
anti-corrosion conductive electrostitive coating is the most common means of prevention and treatment. Anti-static coatings can conduct electricity, mainly because of the addition of conductive materials between the contact and link, forming a conductive path, and ultimately achieve the effect of anti-static.
the current market of anti-static coatings, is basically
doped conductive coatings
. Therefore, anti-static coatings are also divided into: metal system (silver, copper, nickel, zinc, etc.), carbon system (conductive graphite or carbon black), metal oxide system (tin oxide, zinc oxide, titanium dioxide treatment, tin oxide added, etc.) and so on.
carbon-based conductive coatings
carbon-based conductive coatings are an old material, used as carbon-based conductive coatings conductive fillers are mainly
graphite, a variety of carbon black
, graphite fiber, carbon fiber, high-temperature calcined petroleum coke and silicon carbide. With
cheap,
density, not easy to sink, strong corrosion resistance and other advantages.
but the conductivity is relatively poor, and because the surface contains a large number of polar groups, there are difficult to disperse, easy flocculation and other shortcomings. Colors can only be black or dark.
With the development of nanotechnology, the composite of graphite nanomaterials and substations to conductive polymer materials is on the rise, expanding graphite as a new type of conductive filler, with
conductivity good
, small friction loss,
contamination small
and other advantages.the conductivity of
metal conductive coatings
metal conductive coatings depends on the type of metal filler, quantity, type of metal fiber and metal powder, quantity, shape of filler, conductivity can basically meet the requirements, but the color of the coating is limited by the color of the metal powder. Metal fillers are mainly silver powder, nickel powder, copper powder and zinc powder. Because silver powder is more expensive, more used in the military field, less in civilian applications. Although the price of copper powder is low, but easy to oxidize, conductivity is unstable.
Metallic oxide conductive coatings
metal oxides due to its excellent conductivity, light color, better complement the metal conductive pigment corrosion resistance and carbon conductive pigment decoration performance and other shortcomings.
commonly used composite fillers are glass beads, copper powder and mica powder outsourcing silver powder and carbon black outsourcing nickel powder and so on. Metal oxide conductive pigments are mainly doped with tin oxide, zinc oxide, molybdenum dioxide and so on.
conductivity of a conductive coating usually has three characteristics: volume resistivity or conductivity; There is customer feedback, there is always a purchase of products with pressed instruments to measure the surface resistance "non-conformity" problem exists.
, "First of all, there is no national standard or industry standard approved with a pressed resistance test table." In the national standard for the conductive static/static dissipative material test equipment and methods, there are clear requirements: test electrode weight and size, different resistance intervals of the test voltage caused by the resistance measurement results are large mainly due to the pressure gauge output voltage is only 9V, measuring the surface resistance in 10 3-5 times the model, the measurement results are relatively accurate. When measuring a model with a surface resistance of 6-9 times in 10, the result is large due to the low test voltage provided.
addition, the pressure meter and powder model contact is not sufficient, contact area can not meet the requirements of the national standard, resulting in a large resistance test results, such as encountering pattern powder on the impact of greater. "
.