Odour in polymers can be restrained by use of special additives

During plastics processing, additives, plasticizers and flame retardants are used. These additives, and sometimes the polymers, exude unwanted odours in finished products, limiting their applications. One solution- Masking fragrances, is a short-term solution because once the fragrance wears away, the malodor returns. Odour absorbers absorb unwanted odours within the materials, by trapping the VOC molecules.
Ecosorb products react on a molecular level to neutralize odors without relying on chemicals. The fundamental mechanisms involved are adsorption, absorption, gas solubility and reaction. When diluted with water and broadcast via atomization, the tiny water droplets created contain a thin oil skin that creates an electrostatic charge. This charge facilitates adsorption of the malodor molecules onto the droplet surface. The gas is absorbed by the droplet (solubility) and held. OMI Industries' Ecosorb® odor neutralizing products feature a proprietary, natural and environmentally safe formulation for end-product specific odor control applications. It is effective at removing detrimental polymer odors without the use of masking agents or fragrances. For end-product specific odor control applications, they are available in additive formulations that neutralize odors connected with phenolic resins and many others. There are also Ecosorb® products that can be compounded into the plastics that are used in consumer good packaging. Advantages include:
* Effective for both organic and inorganic odors
* Safe for humans and animals
* Safe for the environment, nontoxic
* Custom engineered solutions
Ecosorb products conform with the United States Occupational, Safety, and Health Administration (OSHA) Federal Hazard Communication Standard 29 CFR 1910.1200 that requires manufacturers to be exact in the presentation of information on MSDSs. This technology removes odors from recycled plastics, especially high-density polyethylene (HDPE). Odors absorbed from household or industrial liquids do not affect physical properties of the polymer, but make the recycled plastic unsuitable for consumer goods. Trace amounts of polyethylene imines blended with the recycled plastic remove aldehyde odors typically resulting from rancid fats and oils. The technology also includes a process for manufacturing odor-free films from recycled plastics.
Evonik's TEGO® SORB PY 88 TQ is a highly concentrated deodorant based on the zinc salt of ricinoleic acid for the production of masterbatches and compounds, with excellent odour absorbing properties. It is specially suitable for effectively control odours evolving from products like hydrogen sulfide, mercaptane, thioether, isovaleric acid, amines and ammonia. It provides good heat stability in the compounding process. Compatibility with other chemicals has to be checked for each particular case and application. It is especially suitable for polyolefins (LDPE, PP), rubber compounds and recycled material. (PA and polyolefins) It can be easily dry blended before compounding or directly fed on the extrusion line. Dosage depends on the application and specific formulation in use, as well as on the required performance.
A new plastics additive has been developed to remove taste and odor molecules as they pass through packaging films and other plastic packaging elements. Ampacet's masterbatch additive helps control taste and odor issues in plastics film applications for trash bags and flexible food packaging. Ampacet 101787 removes taste and odor-causing molecules in low density polyethylene (LDPE), linear LDPE and ethylene vinyl acetate films for use in food and nonfood packaging and other applications. The active ingredient is highly porous and preferentially adsorbs smaller, odor-causing molecules, especially ammonium-based (nitrogen-based) and polar compounds. Since it is moderately hydrophobic, it readily removes organic and inorganic compounds in the presence of water. When placed in a polymer structure, this high-surface-area material entraps offensive compounds originating either from outside or inside a package or from the resin itself. It is designed to help control taste and odor issues in such film applications as trash bags and monolayer and multilayer flexible food packaging. It can do the same in many other end uses, including injection blow molded and extrusion blow-molded containers, beverage bottle tops, polyolefin pipe and extrusion coatings. It is effective at relatively low loadings and is typically used at letdown ratios between 3- 5%.
A new polymeric stripping agent from BYK-Chemie is made by adsorbing an aqueous solution of this agent onto a PP carrier. It is added in the compounding operation, and it carries away odor-causing contaminants and VOCs during vacuum degassing. It's recommended at 0.5% to 2% in PP and can also be used in PE. is an easy-to-handle granulate material, which is simply added in the compounding step (extruder)- no further processing step is required. The effectiveness of the product surpasses conventional solutions (e.g. adsorbents).