WILLIAM S . HILL Member, Examining Corps, United States Patent O f i c e Camouflage. No. 2,361,473. Walter C. Granville, New York City, assignor to Interchemical Corporation. This patent is the result of another attempt by the paint chemist to fool the eye and the aerial camera. It seems that armies throughout the period of recorded history have used natural vegetation to hide their movements from the enemy. Modern armies still use branches and bushes to hide installations of guns and observation posts. But fresh green leaves soon fade and must either be replaced frequently or become useless for their intended purpose. So the camofleur first hit upon the scheme of painting strips of cloth with green and yellow paint and using the painted cloth to cover vital installations. This was fine until the observers in airplanes started using cameras and films which detected the diierence between the green of natural foliage and the green of ordinary paint pigments. The difference in the way that natural green foliage appears to the camera's eye and the way that ordinary green pigments photograph is due to the diierence in infrared transmittance and reflectance as well as to the fact that foliage has high absorption in the long wave end of the visible spectrum. The solution to the problem was to develop pigments that not only looked like foliage to the unaided eye hut which would reflect iufrared rays like green foliage. The pigment composition of the present invention depends for its infrared reflectance on the inclusion of certain deep blue colorants, the particular visible shade of the composition being adjusted by the addition of reds and yellows. The deep blue colorants preferred are light fast compounds obtained by coupling tetrazotized dianisidine with beta-oxynaphthoic acid, the anilide of beta-oxynaphthoic acid or with alkoxy substituted anilides of beta-oxynaphthoic acid, of which the latter are the most light stable. Larvicide. No. 2,357,717. Wesley G. Bruce, Dallas, Texas, dedicated to the free use of the People in the Territory of the United States. One of the most troublesome insect pests attacking cattle in the United States is the horn fly. The eggs of this insect are deposited only on fresh cattle droppings and the larvae develop only in such media. Therefore, in order to effect horn fly control i t was necessary to find some substance which could either be administered orally to cattle or mixed with the feed and which would be excreted by the animal, rendering the droppings toxic to the horn fly larvae. Of course the substance had to be nontoxic to the animal.
The patentee discovered that common zinc stearate was a powerful larvicide for horn fly larvae and when mixed with bran and fed in daily doses of 4 g. zinc stearate to each hundredweight of the animal would prevent horn fly larvae from developing in the droppings after the second dose. It was also found that the stearate was very likely toxic to many animal parasites which live in the stomach and intestinal tract. Luminescent Material. No. 2,361,467. Harry M. Fernberger, Cleveland Heights, Ohio, assignor to General Electric Company. The increasing use of phosphorescent and fluorescent materials directs attention to the present patent. Phosphors consist in general of a major proportion of a so-called base material or matrix and a minor proportion of another material called an activator. The luminescent qualities of the phosphor generally depend on the relations between matrix and activator, as determined by heat treatment which they undergo together, as well as on the identity of these materialsthemselves. A preferred base material is cadmium tungstate prepared in any ordinary way, as by reaction between cadmium nitrate and sodium tungstate. During the preparation activators may be added in the form of the nitrate or oxide of bismuth and samarium nitrate or fluoride. The resulting phosphor is said to be powerfully excited by ultraviolet radiation of about 3000 Angstroms to 3800 Angstroms. A modification may be made by adding a minor amount of beryllium to the matrix and using the same two substances as activators. This seems to render the fluorescent light whiter and brighter. These new phosphors may be used as a coating on the inner surface of an enclosing jacket of a highpressure mercury arc lamp or they may he employed to provide color in a design, a dial, a sign, or the like. Lightweight Plastic Composition and Method. No. 2,361,438. Philip S. Turner, Wiliamsport, Pennsylvania. The making of an unusual type of lightweight plastic material is illustrated in the present patent. The pnrpose is to provide a lightweight composition of thermoplastic resin which is suitable for aircraft and other structures. When an uncured phenol-formaldehyde plastic mass is provided with from 2 to 12 per cent by weight of starch granules intimately mixed with or suspended on fibers included in the mass, and that mass is cured, the water and other vapors formed by the chemical reaction, together with the water ori~nallycontained
in the starch and resin, cause the starch particles to sirable as condenser dielectrics. Their high dielectric swell and produce a closed cell structure which has a value saves weight and space in the construction of lower density than the weighted average density of the communication equipment. This is of value not only in ingredients. The swelling of the starch is normally aircraft communication systems but in city telephone controlled to prevent the starch grains from exploding. exchanges. The material formed by the inclusion of starch in the The tetrachloro fluorotolnenes are best prepared by thermosetting resin is a closed-cell type of structure chlorinating their respective fluorotoluenes. This chlohaving each swollen starch grain included in the resin. rination proceeds less rapidly than the chlorination of At the completion of the cure, and upon cooling the toluene itself. In order to cause the chlorination to material, the water vapor captured by each starch proceed satisfactorily iron powder or antimony pentaparticle condenses, leaving in general a. spherically chloride or both are used as catalysts in carbon tetrashaped void in the material much larger than the origi- chloride solution. The resulting product is fractionnal starch grain. ally distilled, and the fraction boiling a t about 269'C. is collected. When purified it is obtained in the form Apparatus for Producing Ice Charged with Carbon of white needles melting a t 146°C. Dioxide Gas. No. 2,361,137. Kenneth F. Terry, Another way of preparing the tetrachloro fluorotoluSan Francisco, California, and James J. Imperaenes is to nitrate the appropriate tetrachloro toiuene, trjce, Fresno, California. reduce the nitro group to the amino group, replace the Although this sounds suspiciously like a well-known amino group with a fluorine atom either by diazotizing comic strip inventor's creations (the "Major" to you) in the presence of hydrofluoric acid or pyrolysis of the this is a bona fide attempt to solve an age-old perplex- diazonium borofluoride. ing problem. The carbonated drinks, both soft and hard, to which Americans are addicted have a tendency Copolymers of Vinyl Halides. No. 2,361,504. Winto go flat as their cooling ice melts. The inventors field Scott, et al., assignors to Wingfoot Corporation, have apparently provided a solution to the problem by Wilmington, Delaware. making carbonated ice. Then as the ice melts i t gives The vinyl polymer plastics have become so widely up its trapped CO,, thus keeping the drink fresh and sparkling. It also seems to obviate the use of that used that anything new concerning them is interesting to a legion of chemists. famous contraption, the soda siphon. The inventors here concerned point out that vinyl The cans in which the ice is frozen are made to chloride and vinyl bromide have each been polymerized withstand high pressures. As the water is frozen, carbon dioxide gas is bubbled up through it and the can's by themselves but apparently the two have never been contents are kept under a pressure of about 65 pounds copolymerized. The copolymer is much more readily soluble in ethylene dichloride and similar solvents than per square inch. is polyvinyl chloride alone and therein lies its utility. The product can be used to advantage in the icing A typical preparation is as follows: to 15 ml. of a of fruits and vegetables, which deteriorate rapidly in an solution of an emulsifying agent such as Aquarex D is atmosphere containing the normal amount of oxygen. added a buffer mixture, such as McIlvane buffer, which The melting ice releases COz which replaces much of gives a hydrogen ion concentration of about pH 7. the oxygen, thus aiding in preserving the perishables. To this is added 1.6 g. carbon tetrachloride, 0.2 g. soTetrachloro Fluorotoluene. No. 2,361,590. Burnard dium perborate, and 25 g. of the desired mixture of S. Biggs, Summit, New Jersey, assignor to Bell monomers of vinyl chloride and vinyl bromide. PolyTelephone Laboratories, Inc. merization is carried out with agitation a t 35°C. for This invention has to do with the production of a 20 to 90 hours. The polymer is obtained from the lagroup of substances having high dielectric constants tex thus formed by the addition of alcohol or by salting and other good electrical properties making them de- out.
The Chicago Section of the American Chemical Society has recently issued a most attractive pamphlet, "The Chemist and the Chemical Engineer in Industry," which should be made available to all prospective chemists and chemical engineers and to all those having to do with vocational guidance. It is more attractively illustrated than any similar publication which we have seen for a long time, and will make the young inquirer think, a t first glance: "If that is what chemists do, I want to know more about it." It is reprinted from the Chemical Bulletin, and copies may be had
from the Executive Oace of the Chicago Section, American Chemical Society, 505 North Michigan Avenue, Chicago 11, Illinois. Along the same line, but not so particularly dedicated to the recruiting of chemists, is a well-illustrated pamphlet from the Battelle Memorial Institute (Columbus, Ohio) entitled, "Research in Action." It describes some of the fascinating work which has been going on in that institution, covering a wide range of fields. Much of it is chemical or closely allied.
