Static Electricity and Elimination in Packaging and Printing (2)

6 Compatible with polymer plastics without blooming, and can maintain the transparency of the packaging film;
7 Capable of 120～300°C high temperature without change;
8 The addition of plastics does not deteriorate the properties due to antistatic agents.
For example, a plastic cornea factory in Hubei because of the improper use of antistatic agents, the production of biaxially stretched PP plastic film when coated on the cigarette box after the cream, instead of affecting the decoration of the bright color quality.
In the paper forming process, especially in the printing process, there are many aspects of static electricity. For example, Danmingkou Guangming Printing Factory used the glue of the Liuliping paper mill in the city and caused mutual adhesion due to mutual attraction. They also caused difficulties in paper feeding and paper delivery, which greatly hindered the normal rapid offset printing operations. At this point, the factory no longer purchased paper from Liuliping. Another example is Nanyang City, Henan Province, a printing factory in the 60,000 high-speed offset printing process, a large number of adsorption of paper dust and other impurities, shift operations only open and stop.
In recent years, the author has learned from the interactions with the operators of packaging and printing companies that: When the static electricity generated by the paper is severe, the air discharge may be caused by an extremely high potential (such as the volatilization of the solvent also causes this failure), resulting in electric shock or fire. Commonly known as "magnetic fog." It is not surprising that there are casualties.
In charged inks, “static ink spots” can often appear on packaged prints, which may be caused by the discharge of the printing machinery during the high speed operation.
For more than a decade, people have not only discovered the “darkness” caused by ink discharge. It also concludes that the discharge of printed graphic lines will lead to the appearance of “black whiskers” and that in the printing process, some of the graphics and texts adsorb dust and cause “printing” of printed products (usually the introduction of silicone oil). eliminate). Recently, we introduced the antistatic agent A into the ink system and the electrostatic phenomenon disappeared.
In addition to the static electricity of printing inks, the electrification of adhesives in paper, plastic pastes, and plastics, papers, and aluminum foils is indispensable in many occasions. The adhesive is misted due to charging, causing serious contamination of the paste and the complex adhesive molding operation environment; employees are also subject to electric shocks by the solvent of the adhesive system. For example, a color printing factory in Xiangfan City was damaged due to inadequate protective measures and was almost destroyed by fire on December 20, 1998. In view of the above phenomenon, zinc oxide is usually introduced into the system so that the generated static charge is leaked as soon as possible.
The static electricity of printing machinery is often due to the static electricity accumulation caused by the strong frictional force of many parts in high-speed operation. The old-fashioned or non-standard ink production with insufficient electricity elimination device, the flexographic flexographic printing, rotogravure and vertical printing of printing processing are not perfect. Sanding or high-speed dispersion of ink, etc., relying on the vulgarity of production and marketing companies has been far from 200 to 300 meters of a multi-color soft, convex, concave high-speed rotary printing and lamination. And 300,000 sheets per hour (60,000 rpm) offset newspapers were printed. This is because when the machine is running at a high speed, the voltage in some places sometimes reaches 20,000 volts, and when the current exceeds 100 μA, the influence of this powerful voltage and current on the process of packaging printing and film heat sealing is intricate and intangible. The production cost will be greatly increased, and in particular, the mechanical discharge will cause harm to the operators. Static electricity directly affects the development of China's flexible packaging industry. This is not an alarmist. It will be one of the serious issues that must be seriously faced before and after the WTO accession.
â–  Elimination measures 1, "grounding method." The metal conductor is electrically connected to the ground, making it equipotential with the earth, and the charge leaks through the earth. This is just the easiest way to eliminate static electricity.
2, "ion neutralization method." The air is ionized to generate both positive and negative ions to neutralize static elimination on plastics, paper, inks, adhesives, and the like.
3, "environmental relative humidity method." For example, the static electricity of the paper, spraying a certain amount of water onto the paper or the floor, after the moisture absorption and moisture absorption overnight can eliminate static electricity and boot printing.
4, "Electrical Law." A corona discharge or discharge device is installed on a packaging printing or laminating machine, or a device equipped with a radioisotope smashing device is used to eliminate static electricity.
5, "antistatic agent method." In the plastic, paper, ink, varnishes, adhesives and other systems to introduce the right amount of light machine or organic antistatic agent.
In addition to structural modification, conductive pathways are formed to achieve antifouling effects.
1 Such as inorganic metals, carbon fibers, carbon black, etc.;
2 organic such as cationic alkyl phosphates, anionic quaternary salts, nonionic polyethylene glycol vinegars or acids, zwitterionic imidazole derivatives, and the like.
The mechanism of action of inorganic and organic antistatic agents varies widely. However, most manufacturers tend to absorb moisture, lubrication, and electrically conductive materials. (Finish)