7 Effective Methods to Rapidly Eliminate Odors from Plastic Products

Plastic products tend to emit unpleasant odors during processing, and continuous efforts have long been made to mitigate this issue. Furthermore, many manufacturers blend virgin materials with a certain proportion of recycled materials, which leads to stronger odors during pelletizing — a common challenge in production. Today, we will share seven effective methods to quickly remove odors from plastic products!

1. Proper Application of Additives

Tertiary amine catalysts used in the production of polyurethane foams often generate strong odors and cause fogging on automobile interior windows. A viable solution is to seek alternatives to these amines. One approach is to employ polyhydroxy compounds, which not only form part of the polyurethane molecular chains but also deliver catalytic activity. Phenol-based stabilizers used in PVC extrusion or calendering processes are frequently replaced by low-odor zinc-based stabilizers. Tin octoate, a heat stabilizer, is also widely adopted for automotive PVC products thanks to its low odor and low fogging properties.

2. Treatment of Recycled Materials

Organic solvent extraction helps remove odor-causing compounds. An advanced solvent extraction technology uses supercritical carbon dioxide as the solvent. This technique has been applied to HDPE and PET to eliminate odorous contaminants on waste oil containers, pesticide containers and other discarded plastic components. The advantage of carbon dioxide extraction agents lies in avoiding complicated post-treatment procedures associated with organic solvents.

3. Adopt Higher-Purity Resins

Trace residual monomers in many plastics, especially polyvinyl chloride, polystyrene, polyvinyl acetate and acrylate plastics, produce unpleasant smells. Selecting resins with extremely low residual monomer content can eliminate such odors.

4. Incorporate Adsorbents

Adding a small amount of zeolite (an aluminosilicate adsorbent) into polymers can remove odors from materials. Zeolite features abundant crystalline cavities capable of trapping small odor-causing gas molecules.

5. Utilize Antimicrobial Agents

Adding antimicrobial agents to plastics can not only reduce odor emission but also slow down surface aging, discoloration and embrittlement of finished products. Commonly used antimicrobial agents include 10,10'-oxybisphenoxarsine (OBPA), triclosan, isothiazolinone (OIT) and pyrithione. Organometallic compounds containing tin and silver are also occasionally used as antimicrobial agents.

6. Apply Desorption Techniques

Place plastics together with odor adsorbents such as activated carbon and high-specific-surface-area silicates; a vacuum environment accelerates the desorption process. Treating plastic pellets with special detergent solutions also facilitates odor removal. Such detergents are generally aqueous or alkaline solutions containing surfactants, which can effectively remove vinyl chloride monomers, styrene, acrylate monomers, acrylic acid monomers, unsaturated hydrocarbons and more.

7. Add Fragrances

This method is applicable to polyethylene, polypropylene and polyolefin thermoplastic elastomers for processes including injection molding, extrusion and blow molding. Adding fragrances to plastics cannot eliminate unpleasant odors fundamentally, yet it serves to mask unwanted smells.