Coal tar content
Coal tar used in this invention, especially the use of coal tar containing 44-75% cyclic compounds, the present invention is used in asphalt-containing polycyclic compounds> 30-60%, coal tar and coal tar pitch of accounting and 10- 100%. Coal tar and asphalt dissolved in a solvent, coal tar and asphalt content in the solvent is 8-90%, especially 10-30%.Coal tar is a bitumen derived from crude coal tar, water gas tar, oil gas tar or from combination of such tars with their constituents. Coal tar is a black and like gilsonite , viscous, naphthalene-like odor, amorphous residue mainly from distillation of coal.
Composition of coal tar
The majority of its composition is poly nuclear aromatic compounds such a aromatic hydrocarbon, naphthalene, phenolic, anthracitic, quinolone compound with trace of insoluble materials. Different grades have different float tests and softening points. Although this invention is not constrained to, the preferred coal tars have a float test at 122 degrees F., seconds: ranging from about 75 to about 230 seconds and more preferably from about 180 to 220 seconds and conform in general to specification outlined by RT-10 (Road tar-10) RT-11 and RT-12 in ASTM D490.