US2306525A - Method of preparing multitone coated articles - Google Patents

Description

' Patented Dec. 29, 1942 METHOD OF PREPARING MULTITONE COATED ARTICLES John Seneca Cummings, Brooklyn, N. Y., asslgnor to Interchemical Corporation, New York, N. Y., a corporation of Ohio No Drawing. Application January 6, 1938, Serial No. 183,675

1 Claim.

This invention relates to novel multi-tone coated articles such as paper, Cellophane, and the like, and to methods of preparing them.

My new multi-tone coated materials comprise base materials coated with films of coating compositions which have been allowed to blush." portions of which films havebeencompacted after drying by heat and/or pressure, whereby ,a multi-tone effect is obtained due to the whiteness added to the uncompacted portion of the film by the blush remaining therein.

The phenomenon of blushing is one well known to the coating industry. While unpigmented coating compositions which dry by evaporation of solvent (lacquers) generally dry down to smooth homogeneous transparent films, it is possible to produce non-homogeneous films by disturbing the solvent balance so that the binder is insoluble in the solvent during some portion of the film-forming operation, and remains insoluble thereafter. In such cases, the binder precipitates out in the form of very small discrete particles of transparent material, with air between the particles; the resultant film is translucent or opaque, appears white to the eye and is generally matte. Nitrocellulose, other cellulose derivatives and resins all can be made to yield such films, either by proper choice of organic solvents, or by judicious use of water in the film; the methods 01' producing such films are well known in the art, largely because a knowledge of the conditions which favor blushing permit formulators to avoid this generally undesirable phenomenon. This type of matte translucent opaque white film has heretofore been used to coat cloth and paper, to produce tracing cloth.

In my co-pending application, Serial No. 75,570. filed April 21, 1936, I have disclosed the possibility of controlling the solvent balance in such compositions so that the film deposited during the early stages of drying is clear and transparent, while the film deposited in the late stages is blushed and opaque, whereby a blushed film is obtained enclosed in a glossy envelope, yielding a glossy opaque finish for paper and the like. I have now discovered that if a film of coat-- in; composition is applied to a surface, and allowed to dry so as to produce either a matte or glossy blushed film, and the resultant film is treated with an embossing roller, the pressure exerted by the embossing roller compacts the blushed film and forces the air out, thereby yielding an entirely or partially clear film in the depression formed. by the embossing roller, while allowing the unembossed portions to retain their original blush. As a result, a novel multi-tone embossed coating is obtained, varying from the original blushed color to the combined eflect of the unblushed coating and the surface behind it. If an ordinary blushed film is used, a variation in gloss as well as intone is obtained, while the type of film disclosed in my co-pending application gives merely a color diflerence.

By coloring the film slightly, the blushed film will yield a pastel shade; after embossing, the color will vary from that pastel shade to much deeper tones of the same color.

My invention makes possible the production 01' multi-tone papers by the use of a single coating composition and operation without the need of printing a multiplicity of colors. Not only is the cost lowered, but the quality of the product is improved, since the use of a single coating layer precludes the possibility of lack of adhesion between different coating layers.

Typical examples of my invention are as follows:

. Example I Y Parts by weight SS Nitrocellulose 5 sec. (wet with 30% butyl alcohol) 13.8 Acetone 5.0 Methyl alcohol (C. P.) 74.4 Water A 4.2 Glycerine 2.6

ing roller is heated to facilitate the removal of air from the thermoplastic coating.

Example I! Ingredient: Parts by weight Cellulose compound-- 4 sec. SS Nitrocellulose (wet with The chrome green is dispersed by grinding in the plasticizer on a roller mill.

This produces a finish similar to the last, except the tones are shades of green.- The lacquer may be applied to Cellophane, paper, etc.

Erample III Parts by weight /4 sec. SS Nitrocellulose (wet with 30% butyl alcohol) -19.0 5 sec. SS Nitrocellulose (wet with 30% butyl alcohol) 5.7 Butyl stearate 2.4 Wecoline" 4.3 Acetone 20.6 Toluol 38.0 Xylol 10.0

This lacquer, when applied to paper, gives a very dull finish. When embossed as in Egzample I, glossy, greyish valleys and dull white\ peaks are obtained. Coloring matter added to t lacquer yields pastel dull high lights and arker glossy valleys.

The examples may, of course, be multiplied indefinitely, since any film of plastic material which is opaque by reason or its air content (blushed) may be cleared up by the application or suflicient pressure, with or without heat, to give a novel multi-tone film.

My invention has many possible applications and is particularly adapted for the manufacture of novelty wrapping papers, wallpapers, Cellophane sheeting and the like, although it may be applied to any sort of surface.

What I claim is: I

The method of making a multi-tone article, which comprises treating a base carrying a blushed film of plastic cellulose derivative coating composition, the color of which is whitened due to occlusion of air in the film, and which filmis capable of being compacted by the application of pressure thereto, by the simultaneous application of pressures varying from area to area of contiguous portions 01' the film, the greatest pressure used being sufiicient to force substantial quantities of air out of the film to compact it and thereby deepen the color thereof, and the least pressure used being lnsufiicient to force corresponding quantities of air out of the film, thereby substantially maintaining the original blushed appearance, whereby a multi-toned article is produced having relatively uncompacted portions of lighter color and compacted portions of deeper color.

' JOHN SENECA CUMMlNGS.