Downloaded by 80.82.77.83 on January 2, 2018 | http://pubs.acs.org Publication Date: June 1, 1973 | doi: 10.1021/ba-1973-0124.pr001
PREFACE 'Tphe term solvents, as used here, refers to organic liquids used to dissolve resins and polymers principally for application in surface coatings. About 3.5 billion pounds of solvents with a value of about 275 million dollars are used annually in the United States for this purpose. Over the past several decades, knowledge of the properties of solvents and resin solutions has been acquired by laborious experimental work. Especially important properties are the evaporation characteristics and solvent power of neat solvents and the viscosity of resin solutions. As the technology of solvents and solutions progressed, interest increased in the theoretical basis for the observed properties. Although the concept of solubility parameter was described many years ago by Hildebrand, interest in this concept was not great judging by the limited work on the topic. It was about 1955 before more active interest was generated in solubility parameter and other aspects of the physical chemistry of solvents. Harry Burrell was instrumental in stimulating the interest of the coatings industry in solubility parameter in 1955 with his noted paper in the Official Digest (now Journal of Paint Technology). Especially since then, many academic and industrial scientists have made important contributions to the theoretical knowledge of solvents. At the heart of the matter was the need and desire to describe solvents and their blends in fundamental terms which deal with the forces among solvent and dissolved resin molecules and the correlation of these fundamental properties to practical properties like viscosity of resin solutions and evaporation phenomena. The Paint Research Institute has been a catalyst in stimulating advances in the field by sponsoring productive fellowships at leading universities. Much of this work, and other contributions, have been published in the Journal of Paint Technology since 1965. A short course on solubility parameters was sponsored by the Paint Industry Education Bureau and presented by Kent State University in July 1972. Investigations of solvents received tremendous impetus in the late sixties with the concern to control air pollution. The well-known Rule 66 of Los Angeles County became effective in 1967 for large solvent users; it classified solvents according to their propensity to induce photochemical smog as manifested principally by eye irritation, but also by oxidant formation and other effects. The adoption and proliferation of air pollution regulations generated the need for industry to reformulate thousands ix Tess; Solvents Theory and Practice Advances in Chemistry; American Chemical Society: Washington, DC, 1973.
Downloaded by 80.82.77.83 on January 2, 2018 | http://pubs.acs.org Publication Date: June 1, 1973 | doi: 10.1021/ba-1973-0124.pr001
of solvent formulations to comply with the composition limitations of the air pollution laws. The computer was enlisted to facilitate the reformulation effort; its effectiveness depended upon the foundation of workable theoretical understanding of the physical chemistry of solvents and solutions. The computer could calculate rapidly a selection of worthy candidate solvent systems which could be checked in the laboratory. Suggested computer formulas met the composition limitations of air pollution laws as well as constraints of evaporation rate, viscosity, and the various solution parameters. Rapid changes have also occurred in resin compositions and in application techniques. These advances have created a demand for new knowledge of solvent systems including combinations of organic solvents with water. This volume covers some new ideas and results along with a modest amount of review in the theory of solvents and resin solutions. Two comprehensive papers cover recent and new information on the pertinent chemistry of solvents as related to air pollution. Finally, several reports are concerned with approaches used by industry to select solvent systems and with the actual solvent systems suitable for some prominent resin types. Solvents used in surface coatings for electrodeposition are covered in an extensive paper. Although comprehensive coverage of solvents would require several books, this volume covers some areas of current interest. It is hoped that these reports will aid and stimulate scientists and practitioners in their study and use of solvents for coatings and related products. ROY W. TESS
Shell Chemical Co. Houston, Texas July 1973
x Tess; Solvents Theory and Practice Advances in Chemistry; American Chemical Society: Washington, DC, 1973.
