The MODERN TREND
of
the
PAINT INDUSTRY* E. E. WARE The Sherwin-Williams Co., Cleveland, Ohio people thought his methods not quite fair, and his conclusions somewhat misleading, on the whole his work has proved of decided benefit to the paint industry and to the public it serves. He did succeed in educating the paint-consuming public that water and paraffin oil had little permanent protective value; and in convincing the paint manufacturer that intelligent cooperation in research and publicity could be of mutual benefit to both manufacturer and consumer. Probably the most beneficial result of this pioneering is the impetus i t gave to the development of chemical paint technology. Supplementing the crusade by Professor Ladd and his associates in condemnation of past evil practices, came the constructive work of Committee D-I of The American Society for Testing Materials, and the research and publicity by the Scientific Section of the Association of Paint and Varnish Manufacturers. The improvement of process and product brought about by these combined influences resulted in a general stabilization of the industry in so far as it applied to retail consumption. The purchaser of industrial,finishes, however, had not kept pace and was still classifying materials primarily on a price basis, with little concern as to future performance. The automobile owner had to figure on refinishing or trading in his car every year if he prided himself on its appearance. Not ,. infrequently the agricultural implement manufacturez was compelled to refinish the machines in his distributing warehouse because they would not retain their salability long enough to reach the customer. The progress of the industry was also retarded by specification writers who, assuming an attitude of superior knowledge of the proper composition of products for their especial uses, wrote into their specifications composition restrictions that left little opportunity for improvement by the manufacturer and gave no assurance of either the best product or the lowest price. Through the influence of such men as Dr. Walker of the Bureau of Standards and the Federal Specification Board, paint specifications for Government purchases gradually changed toward the performance type, giving the manufacturer's chemist an opportunity to utilize the latest developments in raw materials, a t the same time exercising such economies in production * Presented at the~springmeeting of the American Chemical method as might insure minimum cost for a product of satisfactory performance. Society, St. Petersburg, Florida, March 26-31, 1934.
T
HE PAINT industry, as we know i t today, is a comparatively youthful member of the general industrial family. We find historical references to pigmented films as decorative or protective surface coatings even before the Christian era, but the manufacture of paints as a coordinated industry really dates from the advent of "mixed paint." The historical r6sum6 presented by Mr. George B. Heckel a t the Century of Progress meeting covers this ground admirably. We follow with interest his sketch of the march of American paint industry from the days of the struggling paint pioneer Childs, through the period of neighborhood factories operated by journeymen painters, to the mixed-paint era beginning about the middle of the last century, and then to the complex, chemically controlled, highly specialized situation of today. The chemist has had an important influence on the paint industry during the past fifty years, but not until within comparatively recent years may we say that the chemist has exercised a dominating influence. The status of the chemist in the early days is covered by Dr. Tach in an article published in Chemical and Metallurgical Engineering in 1920. While it seems quite certain that he erred in failing to give credit to a number of important members of the profession, some of whom are still active and of considerable influence in guiding the industry's destinies, the contrast between the small group whom he credits with the early success of the industry and the' several hundred chemists, most of them members of the Sqiety, who are now directly or indirectly connected with paint manufacture or utilization is very striking. The reputable paint manufacturer of the past generation, while interested in turning out a good product, was sadly handicapped by competition from others whose only interest seemed to be in marketing a product with a maximum margin of profit. While he may have been satisfied that a paint carrying pure linseed oil as a vehicle, and a combination of lead and zinc as pigments, would give the best protection and decoration as far as his knowledge and experience went, he also was compelled to recognize the unethical methods of unscrupulous competitors who through fraudulent advertising and high-pressure salesmanship made conditions anything but satisfactory. Professor Ladd, of North Dakota fame, pioneered in a campaign for pure paint. While a t the time some
This attitude gradually extended to state, municipal, and railroad specification writers. If there were any diiculties in the way of writing and enforcing a perfect specification, they came from lack of methods and apparatus for accelerated testing. Producers were not satisfied to wait during the normal lifetime of a protective coating before enjoying the privilege of a position on the approved list; nor would conditions permit the continuance of purchases from a source whose product had given satisfaction to the exclusion of other lessfavored producers. Much has been accomplished toward improvement in methods for accelerated testing; hut there is still much more to be done. Every paint laboratory has installed apparatus for simulating actual exposure conditions. Ultra-violet aging tests are very commonly used, although in recognition of the limitations of this type of test they are practically always supplemented by outside exposure tests. Elaborate outdoor testing facilities have been installed in the southern states, particularly Florida, some commercially operated and some privately owned. Even the results obtained from these tests fall short of being truly representative, but are not to be criticized too severely. for they constitute our best efforts to get speedy answers to our problems and, as such, if sensibly interpreted, are of considerable value. In addition to this apparatus for promoting breakdown of the 6lm structure, the paint chemist's labot'atoryandthe laboratory of the industrial userare equipped with all sorts of special devices, both mechanical and chemical, by means of which they attempt to duplicate service conditions. The automobile manufacturer tests for resistance to gasoline, grease, brine, and polishing agents; the refrigerator manufacturer for resistance to changes in temperature, humidity, household grease, sulfur dioxide, and discoloration; the furniture manufacturer for resistance to heat, moisture, and other household influences, even including alcohol; and so on through the whole category of 'industries. Each industry and each superintendent or techqical operator has his own ideas of how he may, by accelerated methods, make certain that the finish he applies to his product will survive and decorate throughout its useful iife. With all its faults, the performance specification for the purchase of paint products is the one that should prevail; and it is to be regretted that certain govemment bureaus, as well as some lesser agencies, feel called upon to assume the responsibility for reverting to the old "composition" idea. An extreme case of the latter has recently come to the attention of our formulators. A county specification writer conceived the following: "The vehicle for the above paint shall be a bleached linseed oil manufactured under the procprocess.' ess known to the trade as the ' Each bidder, under these specifications shall furnish with his bid a certificate from the company controlling process' certifying that the bidder will the ' be able to furnish paint containing a hleached oil
manufactured under the ' process' and supplied by the company controlling the same. No bid will he considered which does not have accompanied this certificate." This looks like a long step backward for an industry whose progress during latter years has been consistently forward. The marked advances that have been made in the manufacture of paint in the past few years have not been confined to any one phase of the paint formula. In pigments we have the development of the new whites such as the modem light-resistant lithopones and the newer double-strength lithopones and modified zinc sulfides. We have titanium oxide and the titanated bases, as well as improvement in the uniformity of the leads and zincs, and an extension of the influence of the suspending inerts. Blacks of all types have come in for considerable attention. Gratifying improvements have been made in density of color, and in physical properties controlling suspension and diiereutial adsorption of vehicle components. Even the relatively unimportant oxides and other earth pigments have come under control of the paint technician. The dry-color branch of the paint industry has kept pace with advances made in other pigment production. Through the installation of better mechanical equipment and through the introduction of more exact chemical control, a uniformity of product has been assured, for hoth shade and physical properties. A study of the effect of dispersing agents has made possible the development of brighter, cleaner colors of superior "wettability." A fund of knowledge has been accumulated covering the effect'of impurities on color precipitation, with the result that through regulation rather than by elimination the color chemist has been able to control certain physical properties. Worthwhile advances have been made in the development of non-bleeding reds, maroons, and viol'ets, and light-fast yellows and oranges hoth in the older chromes and the newer Hansas. The pigment technologist has also interested himself in a study of the physical chemical phase of his product. He has become proficient in the control of such features as hiding power, tinting strength, oil adsorption and dispersion, so that it is now common practice in purchase specifications to confine any pigment to narrow limits in its physical characteristics, as well as to extremely close tolerance in its chemical composition. Paint oils have come in for their share of attention. The early work of Bolley on flax has been supplemented by agricultural chemical studies on other oil seeds and nuts, such as tung, soya, sunflower, and cashew. Recent reports covering studies of the effect of climate on the properties of flax and oil crushed from its seed add considerable worth-while information to our fund of knowledge on flax culture. The widespread Florida tung-oil experiments have kept the attention of varnish makers centered upon the sunshine state.
Professor Burleson's recent work on soya beans, carried out a t the University of Illinois in cooperation with oil crushers and paint manufacturers, will assist greatly in popularizing this valuable crop with the American farmer and its oil with the paint manufacturer and consumer. Coincident with this work on seed culture has been an extensive study of oil crushing, refining, purification, and processing. The synthetic chemist has not been idle in this field as is evidenced by the commercial introduction of a synthetic drying oil that really dries. This new product is a direct challenge to the plant technologist and agricultural chemist. Studies of the constitution of the mixed glycerides of liiseed and other drying oils, which have engaged the attention of a number of investigators, have given us a better understanding of the oil molecule and a clearer insight into the possibilities of adjustment and manipulation to produce results advantageous to the paint formulator. Changes occumng during normal, accelerated, and inhibited drying have been well covered, as has the progress of condensation and polymerization during the course of heat treatment. Volatile solvent research has claimed the attention of an army of research workers. In so far as the protective coating industry is concerned, i t might well be said that the commercializing of lacquer by the du Pont Company inspired a great deal of this particular work. Lacquer created a demand for increased quantities of solvents already available, and the introduction of commercial quantities of known but little used solvents of either better solvent properties or lesser cost. The record of the synthesis of the multitude of alcohols and esters that have made progress in lacquer and synthetic resins commercially possible is in itself an important paragraph in the history of chemical influence on the protective coating industry. Paint drier, while comparatively unimportant, has come in for its share of attention from the synthetic chemist. Although the modem drier still functions as a catalytic promoter of oxidation anti in general makes use of the same metallic oxides, lead, manganese, and cobalt, as in the past, these oxides are frequently combined with acids other than the resin and linseed oil acids so well known in paint practice. The study of the action of these positive catalysts has been accompanied by a study of negative catalysts or antioxidants used primarily to prevent skinning in the package or in storage tanks. Work is actively in progress toward the ultimate goal of suspension of oxidation in the after-stages of film hardening. If oxidation may be suspended when the film has reached the point of optimum toughness, the life of the coating will be prolonged considerably. One of the most pronounced influences on the industry has been the introduction of synthetic resins into varnishes and lacquers. There has been a popular misconception of the reason for the introduction of synthetic products into this, as into other fields. Certainly it may truly be said that synthetic produds in
the paint industry have not been introduced as duplicating substitutes for natural products-with their defects-but rather have they been children of necessity in that they have been introduced to develop new qudities in application, appearance, or performance. Mr. E. C. Holton's summary of the synthetic resin situation, presented before the Association of Paint and Varnish Manufacturers a t their Chicago meeting in 1931, pictures the important changes in the resin field within a comparatively short period, and much further work has been done since his summary was published. Spurred on by the necessity of saving a t least a part of the market for natural resins, whose apparently limited supply during the pre-synthetic period was of real concern to the paint technologist, but which due to the overwhelming acceptance of synthetics threatens to become a drug on the market, the Gum Importers Association has subsidized a study of the properties and technical utilization of these materials. Pteliminary reports of this research promise some very interesting revelations. Synthetic resin developments have compelled the paint technologist to look a t this problem through new glasses. It is increasingly apparent that we may no longer consider a varnish resin to be simply dissolved in the vehicle and functioning in the filmfoundation only as a glossing and hardening agent. We know definitely that we may so formulate that the resin forms an integral part of the a m , influencing not only gloss and hardness, but toughness, elasticity, chemical and weather resistance, pigment dispersion, and stability. In some cases, the relative positio?~of the two major ingredients of the varnish film. have been reversed. The resin in some of the more recently introduced paint products has tough, resistant, film-forming properties in itself and is used with the minimum additions of oil or other plasticizer. While not primarily of interest to the general chemist, mechanical research on grinding machiaery is of decided interest and importance to the paint technologist, especially when we consider that paint grinding is not primarily a question of reduction in size of particle but one of dispersion and wetting. The introduction of plastic dispersion mills, such as rubber rolls and mixers. as well as liquid dispersion by-the so-called .colloid mills, w d the many modifications of the older, more standard types of grinders assumes a position of decided importance. Quite striking advances have been made in pigment dispersion by pulping, a process which, while well developed for lead pigments, has not until recently been seriously considcrcd for such other pigments as may a t some stage in their manufacture have been suspended in water. Even the routine of the paint industry has been disturbed by the technical trend. We are demanding more and more of our protective coatings-package mnditionsettling-uniformity of drying-skinningcrystallization-odor-uniformity of color-as well as
superiority of performance in the hands of the userflow-leveling-hiding-color-flood-bloom-toughness-chalk-recoating-eye appeal-brilliance and retention of gloss. The physical chemical studies of dispersion, suspension, and adsorption that have been reported to the Society in recent years have been of intense interest and importance in pointing the way to a better understanding of the properties of paint mixtures. Added emphasis has been given to a study of adhesion of paint films both from the standpoint of proper preparation of the surface to which the paint is to be applied as well as to the composition and constitution of the film-forming material itself. New ideas have been advanced covering the relations between the nature and porosity of the surface to be coated and the type of paint best suited for this application. The physical structure of the fully dried film has come to he considered as extremely important. It seems quite certain that maximum protection does not necessarily result from the most perfect sealing of the surface; a certain amount of "breathing" is considered by some authorities as necessary for proper adhesion and maximum life. Hand in hand with the research by the raw-material producer and the paint manufacturer has gone the demands of the consuming industry. A great many paint, varnish, and lacquer consumers have placed their finishing rooms under technical control with.a result that not only has there been an important advance in finishing technic through the introduction of finishing schedules to suit the available finishing material, but frequently through closely coijperative research, worth-while additions have been made to the general fund of protective-coating knowledge. Sales methods have kept pace with changes in manufacturing procedure. Sales representatives of both rawmaterial producer and paint distributor are either technically trained or supported by adequate technical service. From a casual survey of the record of @ccomplishment in the paint industry one might gather that the major portion of the research effort has been expended for the benefit of the industrial user. This is really not true, for the retail consumer is still the paint manufacturers' best customer and as such is entitled to first consideration. It is diflicult to bring the results of research and development to the attention of the individual consumer. While the industrial user has technical advice to assist him in the selection of a proper finishing material, the retail buyer uses paint too iu-
frequently to become an expert and consequently has to depend upon the advice of his favorite painter or upon his own reaction to the advertising appeal made to him through the multitude of channels now available to the commercial advertiser. Competition has, however, forced each paint manufacturer to extreme effort toward creating produds that not only appeal to his customer's sense of beauty and to his convenience, but that also promise the most value for his dollar. The result of the trend toward the use of synthetics to replace natural products, or rather of the success of such substitutions as have already been made, has been a tendency on the part of the paint chemist toward the introduction of synthetic materials into all lines of paint products. No longer are we satisfied to introduce the newer materials in places where their specific performance opens a new field; we are also concerned in partial or total replacement of the old-line raw materials with the new wherever an improvement in application of performance may be achieved, even a t an advance in cost. In conclusion, I would like to draw a composite picture of the past few decades in thelife of American paint industry. We see first a painstaking individual effort to serve wisely and well, handicapped by limited knowledge and experience. Next we come to an age of mad scramble for personal gain, a t the probable expense of both competitor and customer. A third glance shows a change of attitude, supported by a gradual acquisition of knowledge of the manipulation and testing of a somewhat narrow range of available materials. Finally we see that part of the picture representing present-day activities. We see the development of an infinite number, of hew products and the compilation of technical data covering both raw material and finished product too extensive for a single individual to comprehend in its entirety. We see agricultural studies of strain, fertilization, and seed selection pointing to improvement of, product, but a t the same time placing particular emphasis on domestic production. We see technical research directed toward synthesis of old materials as a matter of economy and substitution of new synthetics to effect improvement in quality. All of which finally brings us to a vision of the future in which we shall assuredly find a technically designed protective coating built up from improved natural or scientifically evolved synthetic raw material. Whatever the composition we are assured of a product of beauty and utility; for the manufacture of paint has most certainly advanced from an art to a science.
