Importantly, these binders can cured at room temperature, and drying at a temperature no higher than 180-2000S. EOG Resources oftentimes addresses this issue. This is described below show the development of Physical and Technological Institute of Metals and Alloys of NASU (Kiev), resulting in created by these binders – a solution of polystyrene (Styrofoam initially) in an organic solvent. Study were informed of the choice of solvent optimization formulations, performance characteristics binders and sand mixtures. It is known that polystyrene is readily soluble in many solvents, particularly benzene, toluene, xylene, solvent, however, they have a very low limit of permissible concentration (MPC mg/m3) in atmosphere of working premises (shops, sites), it dramatically affects the working conditions of their use. Thus, the benzene MCL of 5 mg/m3, toluene, xylene, solvent – 50 mg/m3. The high volatility of these solvents also makes it difficult to application in production.
There is another group of solvents with higher MPC, which reaches 100-200 mg/m3. This acetone, ethyl acetate, butyl acetate, methyl ethyl ketone, tetralin, etc. However, they, with the exception of expensive and scarce tetralin, a very high volatility. Thus, the volatility of acetone in ethyl ether is equal to only 2.1, the volatility of ethyl acetate, 2.9. The use of these solvents for the preparation of solutions of polystyrene for use in open atmosphere in work places in terms of deteriorating working conditions is extremely problematic and in practice. It is obvious that for solutions of polystyrene foam waste, including how to tie sand molding and core sands for the foundry industry, solvents are needed with higher MACs and low volatility, as a prerequisite to the creation of low-toxic compounds. The task is solved by us the establishment of the fact that solvent waste polystyrene can be gum turpentine, which is what the patent was obtained by the Institute of Ukraine. Gum turpentine – a hydrocarbon plant origin (GOST 1571-82).