How to reduce the bad smell in the processing of waste plastics?



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How to reduce the bad smell in the processing of waste plastics?

Waste plastics process unpleasant odors. In order to eliminate these odors in the future to meet the needs of the environment, waste plastics processors have long been working to eliminate or reduce these odors.

This article provides a brief summary of the method of reducing plastic odor.

1, adding adsorbent
If a small amount of zeolite (an aluminosilicate adsorbent) is filled in the plastic, the effect of removing the odor of the material can be achieved. Zeolites have a large number of crystalline voids that capture small molecules of odorous gases.
Molecular adsorbents have been successfully applied to polyolefin extruded tubing, injection and extrusion blow molded containers, insulation packaging materials, extruded outer packaging materials and sealing polymers. Molecularly adsorbed powders can also be added to plastics as moisture absorbers to remove water vapor, which can also contribute to the odor of plastic products.

2, using antibacterial agents
Adding an antibacterial agent to the plastic not only reduces the odor it emits, but also delays the aging, discoloration and embrittlement of the surface of the product. The most commonly used antibacterial agents are 10,10'-oxobiphenone oxime (OBPA), triclosan, isothiazolinone (OIT), pyrythione. Organometallic compounds containing tin and silver are sometimes also used as antibacterial agents.
3. Using desorption method
Another method of deodorization is to place the plastic in an odor sorbent such as activated carbon and high surface area silicate. The vacuum treatment environment can accelerate the desorption process.
Treatment of plastic particles with a special detergent solution can also help to remove odors. Generally these detergents are aqueous or alkaline solutions containing surfactants. These detergents can effectively remove vinyl chloride monomers, styrene, acrylates, acrylic monomers, and unsaturated hydrocarbons.
4, add fragrance
Adding a fragrance to a plastic does not eliminate the unpleasant odor, but it can cover these odors, which in many cases is sufficient. The method can be applied to polyethylene, polypropylene and polyolefin thermoplastic elastomers by injection molding, extrusion or blow molding.
The retention time of the fragrance does not necessarily equate to the life of the molded part. The retention time depends on the degree of aggregation, the volume to surface area ratio, whether it is exposed to a heated or humid environment, and whether the molded part is tightly insulated from air packaging. Fragrances are generally used in toys, household goods, cosmetic containers, household appliances and gardening equipment.
5, waste plastic odor treatment method
Waste plastics tend to produce unpleasant odors. Most recycled plastics, such as HDPE, PP, PVC, and PET, are washed with aqueous solutions to remove contaminants. However, the odor adsorbed inside the plastic will still remain. The organic solvent extraction method helps to remove odor-causing compounds. The latest solvent extraction method also uses supercritical carbon dioxide as a solvent.
This technology has been applied to HDPE and PET to remove odorous contaminants from oil containers, pesticide containers and other waste devices. The benefit of carbon dioxide extracts is that they do not cause troublesome post-treatment problems with organic solvents.
The odour removal unit is an integral part of the waste plastic pellet extruder and is also effective in removing some of the highly volatile compounds that produce odors.
The high-temperature exhaust gas recovery treatment and utilization equipment of the plastic extruder developed by Anhui Cleaning Environmental Protection Technology Co., Ltd. and Fujian Normal University can be applied to the treatment of waste gas in the production of different kinds of new plastic materials and waste materials, all of which can achieve ultra-low emission requirements.
6, the scale of plastic smell
Smell is a subjective issue that varies from person to person, so how to develop a system scale odor is very difficult. The first step in objectively confirming the smell is to let a group of people identify whether it is pleasing or unpleasant to distinguish the smell they smell.
The latest plastic odour detector is an "electronic nose" device that relies on electronic probe dot matrix and pattern recognition technology to work. Volatile odors can be classified as pleasant, neutral, unpleasant, or reported in terms of strength and molecular aggregation, depending on the specific requirements.

The birth of plastics is a big boon, but the environmental problems in its processing and production process have been controversial. How to make the processing and production of plastics and recycling the whole industry chain more environmentally friendly, we also look forward to more new technologies. Solve the environmentally friendly nature of plastics, such as the processing technology of plastic odors shared today.