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1950-51 Theatre Catalog, 9th Edition, Page 421 (399)

1950-51 Theatre Catalog, 9th Edition
1950-51 Theatre Catalog
1950-51 Theatre Catalog, 9th Edition, Page 421
Page 421

1950-51 Theatre Catalog, 9th Edition, Page 421

to rubbing varnish, but capable of receiving and retaining a higher luster.

Flowing Varnish is on designed to produce a smooth lustrous surface without rubbing or polishing. A good flowing varnish must spread evenly and smoothly, must not set up too rapidly, and, when dry, must present a lustrous surface free from brush marks.

Dipping Varnishes are very fiuid varnishes intended to give, rapidly and economically, finish to articles, without the manual labor of application. The articles are dipped in tanks of special form and then suspended to drain and dry. Many of this class of varnishes are baked after dipping.

Spraying Varnish is especially intended for application by the spraying method in general use for finishing manufactured articles. These products are different only in their higher content of volatile thinner from varnishes intended for brushing.


In the formulation, selection, and use of lacquers, whether of the nitrocellulose or cellulose acetate type, the consumer must rely largely on the producer of lacuqer for information and guidance. These producers employ large staffs of technical specialists in their laboratories, in their plants, and in the field, and are competent to guide the consumer in the selection and technical use of such products.

It is a conservative statement of facts to say that it was the technologists of the lacquer and synthetic resin industries that forced the necessity of research, experimentation and development.

The new science introduced and spoke a new languageechains, linkages, isomers, substitutions in numerical positions, plasticizers, solvents, diluents, syntheticsean entire new language to be mastered and comprehended.

As a consequence, there is not only a new lacquer industry, but a new varnish industry as well, and, in the laboratory, the two, to an extent, coalesce. There is, generally speaking, no distinct line of demarcation between varnish and lacquer. There are, of course, many products which are strictly cellulose lacquers and many which are strictly gum varnishes, but there is no longer any clear dividing line separating the two types. This is altogether to the advantage of the consumer who is thus enabled to select exactly the finish best adapted to his requirements for a definite purpose. On the other hand, the multiplicity of available products leaves the innocent bystander so practically helpless that his only resource is the ancient rule-try all things, hold fast to that which is good-and, when found, keep on trying others which may prove even better.

The last possible linkage or modificatiOn has not been testedethe possibilities are, in fact, almost limitless, and until at least the more promising of these are explored, we must expect new chemical combinations to replace the old ones. This, however, may be afiirmed without reservation: Never, in the agelong history of experiment and investigation, have the products of the industry so amply satisfied the requirements of consumers.



In the earliest meaning, the term lacquer designated a class of extremely fiuid, colorless varnishes, designed to produce a thin lustrous coating on metal surfaces in particular to preserve the original luster by excluding moisture and gases. In more recent years, however, in America and Europe, the term lacquer has become largely restricted to coatings of which the characteristic ingredient is a solution of nitrocellulose.

The range of industrial application of lacquer is very wid%from the coating of lead pencils to the finishing of automobiles and furniture-and each industry has devised means for rapid and economical application. On large scale work, cellulose lacquer is applied by dipping or tumbling. In all cases, the attendant fire hazard must be taken into consideration and adequate provision made for the removal of vapors.

Nitrocellulose lacquers may be used on floors, but it is safest%specially if the fioor be stained-to use a dewaxed shellac varnish as a priming coat. If the floor has already been shellacked and waxed, the wax must be removed completely with solvents before the lacquer is applied.

Lacquer Components

Generally speaking, the clear, solid, film-forming portion of lacquers is composed of nitrocellulose, a gum or resin, and a plasticizer or softener, while the vehicle consists of a solvent which evaporates readily at room temperatures. The film-forming constituents are dissolved in the volatile portion which is carried onto the surface where the film is deposited by evaporating as rapidly as is consistent with the formation of a smooth, strong, and durable surface.

Nitrocellulose, highly flammable but not exposive, is a nitric acid ester of cellulose, produced by subjecting the shorter fibers (linters) of cotton to the action of mixed nitric and sulphuric acids. If the nitration is complete, the product is the familiar explosive, guncotton. The reaction, however, is carefully controlled, stopped at the proper point, and the excess acid removed by washing with alkaline water. The water is removed by centrifuging, followed by a treatment with alcohol to remove the residual water. The final product is the nitrocellulose of the lacquer industry.

The acetic acid ester of cellulose, prepared by a process similar to that for nitrocellulose (acetic anhydride replacing the nitric acid in the reaction), is non-fiammable. Its most important use is in non-fiammable (safety) motionpicture and x-ray film, though it is also finding increasing use in the manufacture of brushing lacquers, lacquers for hot surfaces (steam pipes and the like), airplane dopes and finishes, and other miscellaneous uses.

The raw material for these products is usually obtained by cleaning wornout or discarded motion-picture film, although most of the film scrap available is still of the nitrocellulose type. An appreciable percentage is, neverthless, from virgin cellulose acetate.

The finished lacquers contain plasticizers, resins, oils, solvents, diluents, and the like, similar to those found in the corresponding nitrocellulose lacquers.

Solvents-There are quite a number of organic liquids which dissolve nitrocellulose from which can be chosen those to be used as the vehicle of a lacquer. Some of them are solvents for nitrocellulose alone while some dissolve also the gums, resins, and oils used in the formula. There are some solvents which do not evaporate at ordinary temperatures and so serve as plasticizers and softeners.

The several solvents vary in their evaporation rates, and may be classified as rapidly evaporating, slowly evaporating, and very slowly evaporating. Too rapid evaporation of the solvent may re duce the temperature of the air adjacent to the drying lacquer to such a. point as to cause precipiation of moisture and subsequent clouding of the film. Too rapid evaporation also reduces fiow and prevents the formation of a smooth film. On the other hand, too slow evaporation of the solvent will unduly retard the drying and the final hardening of the film.

Resins*The natural resins, esterified resins*both rosin (as ester gum) and copals-and many of the synthetic resins soluble in lacquer fluids are used in lacquer manufacture.

The list of synthetic resins used in specialized products of the paint, varnish, and lacquer industry includes alkyds, phenolics, ureas, melamines, vinyls, mimylidene, ploystyrene, and silicones. Some of the specialized coatings which involve the use of synthetic resins are designed to be baked on the surfaces for which they are intended, applied in controlled temperatures, or hot as in the case of anti-fouling coating which is applied to ships bottoms with specially heated spraying equipment.

Plasticizers - Since unmodified nitrocellulose films are very hard, brittle, and non-elastic, plasticizers are introduced to insure permanent elasticity, fiexibility, and adhesion, as well as to reduce flammability and improve luster.

Camphor was the earliest of this class used to plasticize celluloid, and early lacquers made from celluloid scrap, therefore, contained it. Castor oil, also one of the early plasticizers, is still in use.

A large number of plasticizerseproducts of modern chemical research-are available.

There is an intermediate type, in which resin and plasticizer are combined.

Other Ingredients-If color is desired, pigments or dyes, or both, can be incorporated in the usual manner, depending on the color required. When pigments are used, the product is called lacquer enamel.

Bronze powders and natural or synthetic fish scales are sometimes utilized to obtain special color finishes.

In some cases, drying oils or inert pigments are incorporated into nitrocellulose lacquers to impart various special properties.

Kinds and Uses of Lacquer

Lacquer dries through the evaporation of solvents and diluents, leaving the solid film in place, Thus, lacquer is strictly an air-drying finish. Oil-base or synthetic finishes dry by oxidation or polymerization and may take much longer to dry, even though baked at elevated temperatures. The speed of drying of a lacquer from a few minutes
1950-51 Theatre Catalog, 9th Edition, Page 421