Evaporation rate naphtha

The evaporation rate can be derived either (1) by a plot of time versus weight using a solvent having a known evaporation rate for comparison or (2) from the distillation profile (ASTM D86 IP 123). Although the results obtained on the naphtha provide a useful guide, it is, wherever possible, better to carry out a performance test on the final product when assessing enviromnental effects. 

Turpentine, the older, more conventional solvent for paints, has now been almost completely replaced with the discovery that the cheaper and more abundant petroleum naphthas are equally satisfactory. The differences in application are slight naphthas cause a slightly greater decrease in viscosity when added to some paints than does turpentine, and depending on the boiling range, they may show some differences in evaporation rates. 

The evaporation rate is an important property of naphtha, and although there is a significant relation between distillation range and evaporation rate, the relationship is not straightforward. 

A simple procedure for determining the evaporation rate involves use of at least a pair of fared shallow containers, each containing a weighed amount of naphtha. The cover-free containers are placed in a temperature-and humidity-controlled draft-free area. The containers are reweighed at intervals until the samples have completely evaporated or have left a... 

Thus one of the most important physical parameters is the boiling range distribution (ASTM D-86, ASTM D-1078, ASTM D-2887, ASTM D-2892, IP 123). The significance of the distillation test is the indication of volatility, which dictates the evaporation rate, an important property for naphtha used in coatings and similar applications where the premise is that the naphtha evaporates over time, leaving the coating applied to the surface. 

Chemically, OXSOL 2000 is alpha, alpha, alpha-trifluorotoluene, an HFC. OXSOL 2000 has a number of desirable properties for precision cleaning, electronics cleaning, aerosol applications, and wipe cleaning. It is a pure compound, with a relatively fast evaporation rate and toluene-like odor. In its pure form, OXSOL 2000 is a good replacement for hexane, toluene, and VM P naphtha where a rapid evaporation rate is desirable and a flammable solvent can be used safely. In addition, OXSOL 2000 can be blended with classical solvents like trichloroethylene yielding non-flammable, very fast evaporating compositions. 

Molecular weight Boiling point, °C Flash point TCC)°F Evaporation rate Bu Ac = 1.0 Specific gravity 25°/2S C Pounds per gallon, 25°C Viscosity, cs, 25°C Vapor pressure 25°C (mm Hg) Surface tension (dynes/cm) Dilution ratio Toluene Naphtha... 

Compound with a strong capability to dissolve a given substance. The most common petroleum solvents are mineral spirits, xylene, toluene, hexane heptane, and naphthas. Aromatic-type solvents have the highest solvency for organic chemical materials, followed by naphthenes and paraffins. In most applications the solvent disappears, usually by evaporation, after it has served its purpose. The evaporation rate of a solvent is very important in manufacture rubber cements often require a fast-drying solvent, whereas rubber goods that must remain tacky... 

An important consideration in solvent selection is air pollution requirements. For this reason solvents such as Laktane (quite fast), VM P Naphtha (medium evaporation rate), and mineral spirits (slow) are generally of interest. The latter two can be purchased to comply with regulations such as Southern California Air Pollution Control District Rule 102 (formerly Rule 66). 

The most commonly used aliphatic solvent is mineral spirits. Several grades are available based on evaporation rate and solvency. Odorless grades are relatively low in odor because they contain mostly isoparaffins, although a lack of naphthenes and aromatics reduces solvency with many resins. Mineral spirits are widely used in architectural paints because their balance of moderate solvency and moderately slow evaporation impart good brushability, leveling and wet edge. VM P naphthas are similar in solvency to mineral spirits but evaporate much more quickly. They are used primarily in sprayed coatings. 

The aromatic solvents provide stronger solvency but greater odor. The most common are toluene, xylene (mixed isomers), and two high flash point aromatic naphthas. The fast evaporating toluene is used in spray paints and industrial coatings. The mixed xylenes, with moderate evaporation rate, are used in industrial coatings, while the slow evaporating aromatic naphthas are used in baked finishes. 

A faster evaporating petroleum solvent with a distillation range of 200-300°F (93-149°C) known as VM P naphtha is sometimes used by painters as an all-purpose thinner however, its rapid evaporation rate may cause the paint to set too quickly. This product is also used by some manufacturers in traffic paints, where a rapid setting and drying time is desirable. 

Solvent cements are generally produced by removing the milled elastomer from the mill and dissolving it in solvent. This cutting of the rubber into a solvent is accomplished in low-speed mixing equipment known as chums or in a variety of high-speed, heavy-duty mixers. For natural rubber and SBR, solvents such as toluene, hexane, or naphtha are commonly used. For nitrile, neoprene, and other polar polymers, polar solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), or chlorinated solvents may be used, alone or in blends with the nonpolar solvents. The blend of solvents finally used by the adhesive producer will depend not only on solvent power, but on the relative rates of evaporation which control drying time. The dissolved rubber can then be blended with whatever additives are needed to obtain the desired adhesive performance. 

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