scope:

Introduction

PAST TO PRESENT

More than a score of years has passed since the previous edition of this manual was published, and many changes have taken place in the coating industry and elsewhere since that time. In 1972, the previous publication date, over 90% of all industrial coatings were low-solids, solvent-borne coatings. Total solids ranged from about 5 to 20% by weight. In the early 1970s, solvents were inexpensive, convenient carriers for the binder polymers used in coatings, and there appeared to be little knowledge in the scientific community about the consequences of breathing them, absorbing them through the skin, or placing them either in the atmosphere or in the environment in general. There were exceptions, as when a particular compound was known to be highly toxic. The specific effect of certain solvents as well as other chemicals on certain segments of the population was unknown in the scientific community. Large quantities of solvent were needed to dilute the high-molecular-weight binders to an appropriate application viscosity. High-molecular-weight binders imparted high-quality characteristics to the final coating. In addition, very dilute solutions allowed application of very thin, but continuous, films. These factors coupled with the low cost of energy used to drive the large ovens associated with coating manufacture were major reasons that kept coating systems low in solids and solvent-borne in nature. Even a large percentage of architectual coatings was oil-based, solvent-borne formulations. In an overall sense, products of the coatings industry worked and did a satisfactory job.

However, new technologies were being talked about, worked on, and even commercialized, albeit in a small way. Terms such as "powder coatings," "radiation-cure coatings," and "water-borne coatings" were beginning to creep into the language of the coating industry. The technologies promised a great deal, were considered mainly by the innovative, and had many difficulties associated with their introduction. Abbreviations such as EPA, MSDS, OSHA, SARA, TSCA, and similar others that are familiar to us today weren't yet in the industry's jargon. In fact, less than two pages (pp. 418-419) in the previous edition of this manual were dedicated to the topic of atmospheric pollution, and therein basically only Rule 66 was briefly discussed. No criticism is meant--such was the nature of the topic in the pre-1972 world. As stated previously, "Times have changed," and this new edition devotes a significantly sized chapter to acquaint readers briefly with the topic of regulation of volatile organic compounds emitted from coatings. This topic and the related topics of health and safety are mentioned a number of times in the manual.