Handbook of Solvents - George Wypych - ChemTech - Ventech!

1044 George Wypych
Table 14.31.1. Relative VOC emissions. [Reproduced from EPA draft Guidelines for
the Control of Volatile Compound Emissions from Wood Furniture Coating
Operations]
Operation
Long process
Percentage of total emissions
Short process Office furniture
Stain 26 28 32
Washcoat 4 4 -
Filler 3 - -
Wiping stain/glaze 8 - -
Sealer 18 32 32
Highlight 1 - -
Topcoat 40 36 36
Table 14.31.2. Reported solvent releases from the furniture and fixtures industry in
1995 [Data from Ref. 2]
Solvent Amount, kg/year Solvent Amount, kg/year
n-butyl alcohol 940,000 methyl isobutyl ketone 590,000
cyclohexane 10 tetrachloroethylene 7,300
dichloromethane 180,000 1,2,4-trichlorobenzene 90
ethylbenzene 360,000 1,1,1-trichloroethane 160,000
ethylene glycol 30 trichloroethylene 29,000
hexane 25,000 1,2,4-trimethylbenzene 140,000
isopropanol 105,000 toluene 5,300,000
methanol 3,600,000 xylene 3,300,000
methyl ethyl ketone 1,900,000
One problem related to all water-base coatings is the degree to which they penetrate
into wood grain. Waterborne coatings are composed of relatively large emulsified particles
which are frequently the size of the pit openings. After the emulsion droplets dry out they
become very viscous and penetration becomes even more difficult. The penetration of alkyd
waterborne coatings was tested by microautoradiography. 6 The results indicate that the penetration
rate is controlled by the viscosity and form of the material (solution vs. emulsion) is
less important.
UV curable coatings have also problems in application to wood finishing. These finishes
need to have low viscosity but it is difficult to formulate 100% solids curable coatings
which have a sufficiently low application viscosity. 7 It possible to formulate waterborne UV
curable coatings but their performance is still an issue.