The demand for antistatic/conductive products in domestic plastics tends to increase, and the quantity of electronic products needs to be increased. There are many varieties, and the antistatic/conductive products of plastic products have attracted people's attention. It is also one of the goals pursued by plastic packaging industry professionals. Basic materials, research and development of plastic conductive / antistatic requirements of the products, additives, masterbatch, replace the expensive imported similar products, develop more suitable for market demand for electronic product packaging and anti-static product packaging. Common products such as: plastic conductive / anti-static gas, infusion pipelines; electronic products with low resistance plastic packaging trays, conductive / anti-static plastic sheet, sheet, foam, conductive film and so on. Men'S Jacket,Leather Jacket For Men,Mens Puffer Jacket,Winter Jackets For Men Changzhou Xinzhi Chain Information Technology Co.Ltd , https://www.zgczxzl.com
Common anti-static plastic packaging generally requires 10 8 ohms or more, can be any color, and the resistivity is below the 8th power of 10, the use of conductive carbon black as the main conductive material, so more black The following is a brief description of the method of using conductive carbon black and plastic blends to produce conductive plastics or conductive masterbatches.
The choice of conductive carbon black The appropriate conductive carbon black, the use of special conductive carbon black is preferred. Special conductive carbon black is relatively common in domestic sales, good dispersion is the first choice of elements, according to the specific application of the product can choose the appropriate conductive carbon black, for example, for the application of thin film, the dispersion and particle size of conductive carbon black is more critical , And thick-walled pipe, the choice of conductive carbon black is relatively simple.
Table 1, the performance of the typical conductive carbon black carrier selection For universal conductive masterbatch, the general selection of a wide range of linear polyethylene LLDPE, powder-based. For example, the grade 7042 resin can be used as a carrier, which is beneficial to the dispersion and processing of special conductive carbon black. It is also more suitable for extrusion blown film. After grafting, it is also used for HIPS ABS PP LDPE HDPE. The special conductive masterbatch is generally chosen as the carrier of the plastic matrix resin with similar melt index, and it is best to choose the same resin as the carrier.
Table 2, LLDPE DFDA-7042 Sinopec Yangzi Petrochemical Co., Ltd. Technical Index Auxiliaries Select additives to use for good heat resistance and good compatibility. Considering the versatility of the variety as a carrier, the necessary grafts, dispersants, antioxidants, and rheological agents should be properly added in order to achieve processability and a wide range of applications.
Processing equipment high-speed mixer, flat twin-screw extruder (building block type) granulation production line, according to their own circumstances, does not emphasize the unity of the set.
Processing Technology (1) Primary Conductive Masterbatch: The special conductive carbon black and the carrier are fed into a high-intensity machine at a predetermined ratio, additives such as a dispersant, an antioxidant, and a grafting agent are added, and they are stirred and mixed together, and then the twin-screw is extruded. Out. This is called the primary conductive masterbatch and can be used for ordinary pipe materials. The amount of addition is about 20%.
The concentration of carbon black in ordinary carbon black conductive masterbatches will not be very high, especially the mixing of nano-sized carbon black and resin, it is difficult to achieve a high amount of added, it is easy to see the open flame with high added amount, until the decomposition of the resin .
(2) The primary masterbatch is dried, and the secondary extrusion granulation is performed after the filter screen is installed. This process can be manufactured as a special purpose/
General masterbatch, or diluted to the required concentration, can be used as a conductive masterbatch after packaging. As a plastic masterbatch must have sufficient concentration and its conductivity resistance, when the conductivity is generally less than 50 ohms. As the masterbatch is the final product, please pay attention to the use of various conductive carbon black in the resin filter threshold, excessive use of no practical significance!
Application example Primary conductive masterbatch LLDPE powder as carrier, special conductive carbon black content of more than 20%, adding graft, dispersant, antioxidant, rheological agent, after secondary processing of plastic drop resistance masterbatch ( Reduce the surface resistance. Its surface resistance is less than 100 ohms.
In the application of high-impact polystyrene plastic sheet, 15 parts of resistance-reducing masterbatch can be used to obtain 8-6 power permanent anti-static sheets with surface resistance of 10; 30 parts are added to obtain 4 times of resistance less than 10 times. Square conductive sheet. Fully meet the needs of the electronics industry packaging.
For the application of ABS and PP injection molding, adding 50 parts of resistance-reducing masterbatch can produce 4th to 10th 6th power injection products with a resistance value of 10.
For the application in blown film, adding 40 parts of the resistance-reducing masterbatch can give a product with a resistance of 10 about 5th power.
What needs to be explained here is that, due to the injection pressure and shearing action, the surface resistance will be greatly reduced; similarly, the difference in the stretching of the blown film will reduce the conductive effect.
The application of resistance-reducing masterbatch in plastic sheeting prompts extruder requirements: screw diameter: 90-105mm, length-diameter ratio <33:1, screw: PS.PP-specific, front end has a mixing section, sheet forming Pressure 12-14MPa
Second Extrusion Mould: coater-type extrusion die special die, with automatic screen change system, filter: 80 stainless steel for easy three raw materials mixing: high-speed kneader, in accordance with the required surface resistance requirements of the sheet Add different proportions of resistance-reducing master batch, put it into the kneader, stir for 3-10 minutes, if there is a small amount of water, it will be eliminated in the process. If there is excessive moisture, it is recommended to use the dryer or increase the mixing time.
High-speed stirring can also remove non-sheet materials used for unknown reasons. They will be adsorbed on the top of the pan due to centrifugal force/electrostatic separation and you can easily remove them.
Four calendering rollers: temperature 60°C. Cooling roller temperature less than 40°C; roller pressure: 6 KG/cm2 or less. Excessive temperatures can cause loss of surface resistance. The excess material between the calendering rolls should not be too much, otherwise the pressure orientation will occur, there will be similar consequences of over-stretching, the longitudinal strength decreases, and the surface resistance decreases.
The stretch of five sheets has an effect on the surface resistance, and the greater the tension, the lower the resistance. Especially for hot stretching, that is, the distance between the die exiting the die and the calendering roll is 5 to 10 cm. There is slight sagging for unstretched flatness and slight stretching for excessive stretching to stretch or excessive stretching; Hot stretching - often appear on the table