Where does the VOC in plastic processing come from, and where do they 'remove'?

In the production process of plastic products, the possible waste can be divided into three categories: solid, liquid and gas. Among them, gas waste has more sources and is more harmful. It mainly includes two types of volatile organic gases (VOC) and inorganic volatile gases. Among them, the organic volatile gas VOC has a huge impact on human health. For example, when the VOC in the environment reaches a certain concentration, people will feel headache, nausea, etc. in a short time. In severe cases, they will experience convulsions and coma, and will damage the human brain and nervous system, causing serious consequences such as memory loss. 1. What is VOC gas? VOC is the abbreviation of Volatile Organic Compounds, which has strong volatility in the temperature range of 50-260°C. Common volatile organic compounds include: (1) benzene (such as benzene, toluene, xylene, ethylbenzene); (2) alkanes (tetradecane); (3) aldehydes (formaldehyde); (4) Alcohols (ethanol); (5) Ethers and esters (ethyl acetate); (6) Ketones (acetone). These VOC gases are generally invisible to us, and the smells you smell are not all the smells of these gases themselves. The main sources of the taste of these organic substances include: (1) the smell of formaldehyde produced by decomposition in the production of POM; (2) the sourness of the HCl produced by decomposition in the production of PVC when it meets with water; (3) the monomer in the processing of ethylene-vinyl acetate copolymer Vinegar smell released by vinyl acetate residue. 2. Where does VOC gas come from? 1. Printing inks (1) Solvent inks will produce VOC pollution such as benzene, ketones and ethyl acetate during printing and drying. But the printing effect is improved, especially for plastic substrates. (2) The content of organic solvents in water-based inks is low (about 20%), so there are less VOCs during use (drying). 2. Acrylic and polyurethane adhesives commonly used in adhesives are still mainly ethyl acetate organic solvents. 3. Surface coating coating can eliminate various defects on the surface of plastic products, and give the products the functions of conductivity, antistatic, and wear resistance. It can also turn dark plastic products into light-colored products. Commonly used acrylic or polyurethane coatings. 4. Mold release agents are commonly used in mold release machines that contain organic solvents such as CH2Cl2, CH3CHCl, and so on. 3. How to get rid of VOC gas? 1. Choose resins with lower residual monomer content as much as possible and use resins with lower residual monomer content. For example, the content of VC monomer in medical PVC resin is very low, and the VC content can reach 1ppm (mg/kg) (normal value is 5); PP for automotive interior panels must choose a resin with low volatile content of small molecules. 2. Use the auxiliaries with larger molecular weight as much as possible, choose the auxiliaries with larger molecular weight, preferably polymer additives, to ensure that there will be no volatilization and external migration at processing temperature. (1) If the coupling agent is changed to a compatibilizer, specifically a graft polymer or a graft polymer, but the maleic anhydride graft part has a certain odor. (2) Polypentaerythritol stearate (PETS), etc. for lubricant; polyethylene wax (PE-WAX) with molecular weight greater than 5000 is used as dispersant. (3) Use polymer types as much as possible for flame retardants, such as brominated polystyrene, brominated epoxy resin, and PVC resin. 3. Increasing the adsorption of inorganic substances will adsorb the small molecule volatiles that may be produced with high-absorption materials, so that they will not be released under normal conditions. Commonly used inorganic adsorbents are activated carbon, molecular sieves, diatomaceous earth, synthetic calcium silicate and so on. 4. Control processing conditions (1) Low-temperature production: Under the premise of ensuring that the product is fully plasticized, the processing temperature is lower, thereby reducing the production of small molecule decomposition substances. (2) Multi-stage vacuuming: increase the number of vacuuming to reach level 3 or even 4, and remove the small molecule volatiles produced in time. 5. Reduce the use of organic solvent-based materials (1) Water-based paint: Water is used as a dispersion medium to replace organic volatile solvents. The current technology still needs to contain about 20% ether and alcohol solvents, which can only be regarded as low-VOC paints, not VOC-free paints. (2) Solid powder coatings: without any organic solvents, zero VOC emissions. (3) Light-curing coating: The film-forming material is formed by light-curing reaction, which can reduce the amount of organic solvent used, but it often needs to contain about 30% of organic solvent. (4) Water-based adhesives and water-based release agents: currently available are products with low content of organic solvents. At present, consumers have become more stringent on the VOC requirements of plastics used in automotive interiors. How to reduce the VOC release of modified plastics during processing and use is the research focus of various modification companies. There is a new type of VOC solvent recovery device. This device uses activated carbon fiber (ACF) as an absorbent to treat exhaust gas containing organic solvent (VOC) discharged from various factories or equipment, and convert the VOC into liquid for separation. Recycling and reuse. VOC is the English abbreviation of volatile organic compounds, a type of carbon compound that can participate in atmospheric photochemical reactions. This type of substance is often used as raw materials and solvents, and is passed in the production process. Different means enter the atmosphere and pollute the atmosphere. Standard Group uses activated carbon fiber as an adsorbent to undertake the design, processing and manufacturing business of VOC exhaust gas adsorption and recovery equipment. More VOC solvent recovery equipment http://www.standard-groups.cn/ chanpin/glcljcy/qkxfjwkfxy/3681.html