Paints & Coatings Solvents Air Monitoring Applications
Solvents are one of the three components of paints. They are petroleum-based chemicals which dissolve the pigment and binding agent for application. Most enamel-based paints use a mild petroleum-based solvent with an alkyd vehicle, and have a long drying and curing time. Conversely, lacquer-based paints require stronger solvents to speed the drying time. The most widely used aromatic hydrocarbons solvents in paint are benzene, toluene, mixed xylenes, ethylbenzene (BTEX), and high flash aromatic napthas; aliphatic hydrocarbons include hexanes, heptane, VM&P naphtha.
Section Overview
Air Sampling Media by Regulatory Method | ||
|---|---|---|
| Method | Contaminants of Interest | Sampling Media |
| OSHA | ||
| OSHA 7 | Organic Vapors | Sorbent Tube – Coconut Charcoal; ORBO-32S (20267-U) Passive Sampling-Radiello BTEX/VOCs-(RAD130)/(RAD145) |
| OSHA 12 | Benzene | Sorbent Tube – Coconut Charcoal; ORBO-32S (20267-U) |
| OSHA 16 | Methyl ethyl ketone (MEK) | Sorbent Tube –Silica Gel; ORBO-52S (20229) |
| OSHA 48 | Petroleum Distillate Fractions (PDF) | Sorbent Tube – Coconut Charcoal; ORBO-32S (20267-U) |
| OSHA 69 | Acetone | Sorbent Tube – Carbosieve S3; ORBO-91 Passive Sampling-Radiello BTEX/VOCs-(RAD130) |
| OSHA 84 | Methyl ethyl ketone (MEK) | Sorbent Tube – Carbosieve S3; ORBO-91 |
| OSHA 1002 | Xylenes / Ethylbenzene | Sorbent Tube – Coconut Charcoal; ORBO-32S (20267-U) Passive Sampling-Radiello BTEX/VOCs-(RAD130/RAD145) |
| OSHA 1004 | Methyl ethyl ketone (MEK); Hexone | Passive Sampling-Radiello BTEX/VOCs-(RAD130) |
| NIOSH | ||
| NIOSH 1003 | Hydrocarbons, halogenated | Sorbent Tube – Coconut Charcoal; ORBO-32S (20267-U) |
| NIOSH 1501 | Aromatic Hydrocarbons | Sorbent Tube – Coconut Charcoal; ORBO-32S (20267-U) Passive Sampling-Radiello BTEX/VOCs-(RAD130) |
| ASTM | ||
| ASTM D3686 | Organic Vapors | Sorbent Tube – Coconut Charcoal; ORBO-32S (20267-U) Passive Sampling-Radiello BTEX/VOCs-(RAD130) |
| ASTM D6196 | Volatile Organic Compounds (VOC’s) | Thermal Desorption Tubes Passive Sampling-Radiello BTEX/VOCs-(RAD145) |
Aromatic Hydrocarbon Solvents
Aromatic hydrocarbon solvents have a benzene ring structure. These solvents are produced in the petroleum refining industry from the distillation of petroleum stock and other chemical conversion processes, such as catalytic hydrogenation and alkylation. These solvents impart stronger odors and have higher solvency rates than aliphatic hydrocarbon solvents.
Common aromatic hydrocarbon solvents used in paints and coatings are benzene, toluene, ethylbenzene, mixed xylenes (BTEX) and high flash aromatic naphthas. Additional information can be found under our Petrochemical Industry VOCs guide. Aromatic solvents are also widely used in printing inks, pesticides, insecticides, and agricultural chemicals.
Short-term exposure to these solvents from inhalation can result in irritation to the upper respiratory tract and eyes, also dizziness, fatigue and headaches. Long-term effects may cause disorders in blood (benzene); cardiovascular and kidney effects, unconsciousness, dysfunction of the CNS (xylene). Benzene is classified as a human carcinogen.
References
- ASTDR - Ethylbenzene (PDF)
- NIOSH Topic - Organic Solvents
- ASTM - Volume 06.04 March 2009: Paint, Solvents, Aromatic Hydrocarbons (list of standards) (PDF)
Aliphatic Hydrocarbon Solvents
Aliphatic hydrocarbon solvents do not contain a benzene ring. They are mixtures of either saturated, long straight chain (normal-paraffin) or branched chain (iso-paraffin) or cyclic paraffins. These solvents are produced by distillation of crude oil by the appropriate boiling point range fraction, then are treated to improve color and odor.
Short-term exposure to these solvents may cause dizziness, giddiness, nausea and headaches, irritation to skin and eyes, and euphoria sometimes resulting in unconsciousness. Long-term effects include muscular weakness, blurred vision, headache, fatigue, numbness, damage to lungs and skin, and neurological disorders.
In addition to their use as solvents or diluents in paints and thinners, they are widely used in oil extraction, degreasing, rubber manufacture, and as carriers for aerosols and disinfectants. Gasoline and kerosene are examples of aliphatic hydrocarbon solvents.
Common aliphatic hydrocarbon solvents used in paints and coatings are mineral spirits, hexanes, heptanes, and VM & P Naphthas.
Exposure Limits | |
|---|---|
| Agency | Exposure Limit |
| Mineral Spirits (Stoddard Solvent, Petroleum Solvent, VM & P Naphtha) | |
| OSHA (PEL) | for General Industry: 2900 ppm; 500 mg/m³ ppm TWA for Construction Industry: 1150 ppm; 200 mg/m³ ppm TWA for Maritime: 1150 ppm; 200 mg/m³ ppm TWA |
| ACGIH (TLV) | 50 ppm, 525 mg/m³ TWA; 100 ppm |
| NIOSH (REL) | 350 mg/m³ TWA, 1800 mg/m³ Ceiling (15 min) |
| NIOSH (IDHL) | 20,000 mg/m³ |
| (TWA=Time-weighted average; TLV=Threshold Limit Value; PEL=Personal Exposure Limit, REL=Recommended Exposure Limit; IDHL=Immediately Dangerous to Life and Health concentration) | |
Oxygenated Solvents (Active Solvents)
Oxygenated solvents are synthetic compounds with oxygen functionality. These solvents are primarily used as active solvents for most synthetic resins due to their strong solvency. They dissolve resins and films; reduce viscosity of paints, varnishes and lacquers for application. The four most widely used in this category are: ketones, esters, glycol ethers, and alcohols.
Ketones
Ketones are commonly synthesized from the oxidation of hydrocarbons. Ketones feature a carbonyl group bonded to two other carbon atoms or alkyl group. They have very strong solvency, a wide range of evaporation rates and also a very distinct, strong odor. The commonly used ketones in paints and coatings are: acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and isophorone.
Other uses for Ketones: Acetone and MEK are components of solvent mixtures in neoprene, nitrile rubber, and urethane industrial adhesives. Acetone is widely used in the pharmaceutical industry to extract Vitamin B complexes, alkaloids, enzymes and antibiotics. MEK and MIBK are used to dewax oils and also to aid in the extraction and purification of antibiotics; production of smokeless powders, inks, degreasing applications, perfumes, cleaning fluids, antioxidants, and more.
Exposure Limits | |
|---|---|
| Agency | Exposure Limit |
| Acetone | |
| OSHA (PEL) | for General Industry: 1000 ppm; 2400 mg/m³ ppm TWA for Construction Industry: 1000 ppm; 2400 mg/m³ ppm TWA for Maritime: 1000 ppm; 2400 mg/m³ ppm TWA |
| ACGIH (TLV) | 500 ppm, 1187 mg/m³ TWA; 750 ppm, 1780 mg/m³ STEL; Appendix A4 - Not Classifiable as a Human Carcinogen |
| NIOSH (REL) | 250 ppm; 590 mg/m³ ppm TWA |
| NIOSH (IDHL) | 2500 ppm |
| Methyl ethyl ketone (MEK) | |
| OSHA (PEL) | for General Industry:200 ppm; 590 mg/m³ ppm TWA for Construction Industry: 200 ppm; 590 mg/m³ ppm TWA for Maritime: 200 ppm; 590 mg/m³ ppm TWA |
| ACGIH (TLV) | 200 ppm, 590 mg/m³ TWA; 300 ppm, 885 mg/m³ STEL; BEI (TLV listed under Methyl ethyl ketone (MEK)) |
| NIOSH (REL) | 200 ppm, 590 mg/m³ TWA; 300 ppm, 885 mg/m³ STEL |
| NIOSH (IDHL) | 3000 ppm |
| Hexone (MIBK) | |
| OSHA (PEL) | for General Industry: 100 ppm; 410 mg/m³ ppm TWA for Construction Industry: 100 ppm; 410 mg/m³ ppm TWA for Maritime: 100 ppm; 410 mg/m³ ppm TWA |
| ACGIH (TLV) | 50 ppm, 205 mg/m³ TWA; 75 ppm, 307 mg/m³ STEL |
| NIOSH (REL) | 50 ppm, 205 mg/m³ TWA, 75 ppm, 300 mg/m³ STEL |
| NIOSH (IDHL) | 500 ppm |
| (TWA=Time-weighted average; TLV=Threshold Limit Value; PEL=Personal Exposure Limit, REL=Recommended Exposure Limit; IDHL=Immediately Dangerous to Life and Health concentration) | |
Esters
Esters are typically derived from an inorganic acid or organic acid where there is at least one hydroxyl (-OH) group replaced by an alkyl (alkoxy) group and most commonly from carboxylic acids and alcohols. Esters as solvents are alkyl acetates and propionates and glycol ether acetates. Their volatility is equivalent to ketones. They have strong solvency but generally weaker than ketones of the same volatility.
Glycol Ethers
Glycol Ethers commonly known as Cellusolve® are a group of solvents based on alkyl ethers of ethylene glycol and they typically have both ether and alcohol functionality. These compounds were used extensively in coatings until concerns arose about their safety risks. They are being replaced with propylene glycol ethers in many applications. These compounds have strong solvency combined with slow evaporation rate.
References
- Methyl Cellosolve Safety (PDF)
Alcohols most commonly used in paints and coatings are butyl alcohol and ethyl alcohol. Alcohols have a low toxicity and can dissolve non-polar compounds and are used in paints and coatings to speed drying time or to thin paint viscosity.
Applications
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