M
Re: Smelly Varnish - Consumer Complaints about the device being “smelly”
Regarding solvents, a classic smell-source is a change by the formulator, often for air quality or RoHS/REACH reasons, from a mix of fast/slow aromatic and aliphatic simple hydrocarbons (naptha, toluene/xylene, short-chain ketones) to a mix of more complex hydrocarbons. N-methyl pyrrolidone for instance is quite smelly over a long evaporation period. Longer-chain ketones can be more smelly.
Low toxicity/low VOC solvent blends are always suspect for smell in my experience.
Relatively few industrial varnish users are still using traditional oxidizing materials i.e. alkyds, but those can go from no-objectionable-smell to smelly if they're blended with oxidizable oils that are contaminated or (worst case) rancid.
Sometimes solvent changes to decrease cost or that occur in a vendor change for other reasons and aren't realized, with the new materials being whatever-was-in-the-process blends and containing quite small percentages of complex and highly odiforous materials, i.e. esters etc., can be at blame as well.
Sometimes solvent blends are changed seasonally in the course of normal production engineering to manage varnish performance in a process that's done in a shop with incomplete HVAC control, where seasonal humidity and temperature shifts affect drying.
Regarding solvents, a classic smell-source is a change by the formulator, often for air quality or RoHS/REACH reasons, from a mix of fast/slow aromatic and aliphatic simple hydrocarbons (naptha, toluene/xylene, short-chain ketones) to a mix of more complex hydrocarbons. N-methyl pyrrolidone for instance is quite smelly over a long evaporation period. Longer-chain ketones can be more smelly.
Low toxicity/low VOC solvent blends are always suspect for smell in my experience.
Relatively few industrial varnish users are still using traditional oxidizing materials i.e. alkyds, but those can go from no-objectionable-smell to smelly if they're blended with oxidizable oils that are contaminated or (worst case) rancid.
Sometimes solvent changes to decrease cost or that occur in a vendor change for other reasons and aren't realized, with the new materials being whatever-was-in-the-process blends and containing quite small percentages of complex and highly odiforous materials, i.e. esters etc., can be at blame as well.
Sometimes solvent blends are changed seasonally in the course of normal production engineering to manage varnish performance in a process that's done in a shop with incomplete HVAC control, where seasonal humidity and temperature shifts affect drying.