CHEMICALS
working o n behalf of t h e Navy Bureau of Aeronautics. Snell's early work in this field involved the development of various water repellent lacquers. T h e problem with lacquers, however, was that they took about six to eight hours to dry and tended eventually to crack and peel off. T h e advantages of the new silicone preparation are its: • ease a n d speed of application • durability and effectiveness • high transparency • relatively low cost (United Air Lines estimates that t h e total cost of labor and materials for a single windshield application is about $1.25)
United Air Lines, the first commercial line to p u t t h e new material into operational use, applies the rain repellent to a plane windshield
The new product, which is currentiy being marketed b y Snell b u t will be available for licensing, forms a hard coating t h a t makes water behave like beads of mercury. When rain hits the treated windshield of a fast moving plane, the drops are immediately swept off by the onrushing air. How a b o u t the use of this product on automobile windshields? Says Cyril S. Kimball, executive vice president of Snell: "Until automobiles are traveling at speeds of more than 100 miles an hour, the product will only b e of interest to gadgeteers. Possible use t o ehminate salt spray encrustation on speed boats may be the next field for testing this material." C 1
Hansa Yellow G in Paste
Film Defies Raindrops New silicone preparation for aircraft windshields ensures good visibility despite drenching rain J \ PERENNIAL PROBLEM in high speed
aircraft is what t o d o when it rains. Specifically, how can t h e pilot maintain good visibility even though his windshield is being flooded with raindrops? Obviously, ordinary windshield wipers won't work; at high velocities they'd immediately be ripped off. A more practical solution : treat the windshield with chemicals that will prevent raindrops from adhering t o the glass. I n recent years, a variety of preparations containing silicones and other materials have been developed for this purpose. T h e latest—and one that offers outstanding promise—has recently been developed by Foster D. Snell. The U. S. Navy has already received 20,000 kits containing t h e Snell preparation for use on its aircraft, a n d a large order is expected from the Army. U n i t e d Air Lines h a s just announced that by May of this year it will be using the n e w rain repellent on all of its airplanes. United is t h e first com1928
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APRIL
16, 1 9 5 6
mercial airline to put the product into operational use, although other airlines are expressing considerable interest. • How It's Used. In the application of this product, t h e windshield is first cleaned with a solvent such as isopropyl alcohol. Next, a small amount of black bonding paste, consisting of carbon black, silicone (amyl triethoxysilane), and a solvent, is rubbed onto t h e surface. T h e glass is then coated Vvith a mixture of spermaceti, paraffin, a n d polyethylene waxes. Finally, t h e glass is buffed with a clean cloth t o form a smooth, invisible coating. Total preparation time is less than 15 minutes. Each application will last for about five days of continuous rain, after wliich. t h e windshield can be cleaned and recoated. T h e new rain repellent, which can be applied equally well to glass or plastic, is the result of four years of research headed by Snell's J. Mitchell Fain,
A flushed Hansa Yellow G pigment in paste form is offered by Hilton-Davis Chemical to the paint and protective coatings industry for t h e first time. The company says t h e n e w pigment should provide t h e trade with a muchneeded color heretofore unavailable in flushed form. Hilton-Davis manufactured Hansa Yellow G by transferring the pigment from the aqueous pulp to an oil p h a s e through the medium of pigment flushing. I t is an organic azo pigment produced b y coupling m-nitro-p-toluidine and acetoacetanilide. Flushing was accomplished in a medium-short, pure glycerol phthalate soya modified alkyd resin, a n d was reduced with mineral spirits. Principal applications of the flushed Hansa Yellow G are stated as being in finishes where high brilliance, excellent light fastness, a n d resistance to alkalies are desired. C2
• Phthalocyanine
green
toner
has
been a d d e d to American Cyanamid's line of pigments. Company says it has high strength a n d excellent stability^ to light in exterior finishes. Called Cyan Green Toner 15-3100, pigment is said to be essentially nonbleeding in organic
New Text Davison pioneered in the development of the first commercially useful silica gel more than three decades ago, and for years has been America's leading producer. Silica gel, with its porous amorphous physical ^structure providing a surface area of 90,000 square feet per cubic inch, is a unique compound of continuing importance and increasing application. Silica gel's most important properties are its ability t o condense and retain condensable gases in the porous structure and its regenerable nature t h r o u g h the application of hi eat o r other elutriation methods. A wide variety of particle sizes, densities andadsorptivc capacities are available, each having been developed t o meet specific application demands. Investigate Davison Silica Gel, now. See your Davison Field Service Engineer or write for technical literature.
New Text APRIL
16,
1956
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CHEMICALS $©!vomîfcs amdl to joosse&s escelffienBî: eoI©r « r h a l h i l i i î y i m Ibottlb S b o l l SJmsl a l k s î m e EEt«€ÎÎa
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• Antimicrobial^ organic, i n t r o d u c e d by Steeker Chemicals is said t o exhibit Mgh d e g r e e of substantivity to textiles aœd paper» Called ASC-4, c o m p o u n d mssey be· u s e d t o treat wool a n d synthetic fabrics with t h e dye in t h e d y e bath, producing: textiles w h i c h retain activity after laundering and d r y cleani n g . I n p a p e r manufacturing, ASC-4 acldecf at t h e beater or h y d r o p u l p e r res u f e i n p r o d u c t s possessing germicidal properties,, c o m p a n y says. C5 • Texos-U. S. Chemical has discontinu e d Synpol 1 7 1 0 from its s t a n d a r d line of polymers.
• Lake Chemical has developed what is said to b e a n e w a n d improved Oyltite-Stik for sealing oil leaks under greater pressure a n d temperature. N e w formulation has proved satisfactory for use on h o t oil pipes w h e r e pressures up to 7 5 p.s.i., and temperatures up to 400° F., are encountered, company says. C6 ί Lacquer for coating and decorating cellulose a c e t a t e has b e e n developed by Schwartz ChemicaL Called Rez-nLac A, lacquer is said to b e quick dry ing and to h a v e excellent adhesion, C7
• Three cyclic nucleotides introduced by Schwarz L a b s are adenosine 2':3qyclic phosphate, cytidine 2':3 / -cyclic phosphate, a n d uridine 2':3'-cyclic phosphate, as t h e barium salts. Schwarz says cytidine 2':3'-cyclic phosphate is first commercial offering of a standard ized stable substrate for ribonuclease activity. CS
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• Modified e p o x y resin system devel oped by F u r a n e Plastics, Epocast 15, is designed for electronic insulation ap plications requiring a semirigid, low modulus material t h a t will offer high electrical resistance throughout a tem perature range of —65° F . , to at least 300° F. C o m p o u n d is offered as twocomponent, clear imprégnant a n d as a two-component filled potting a n d encapsulating medium. CÇ*
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• Goodyear Tire and Rubber's pack aging films department has developed a n e w Pliofilm known as 75ST Shrink Tite PHofilm. Film shrinks approxi mately 1 8 % w h e n heat is applied, com p a n y says, resulting in skin-tight pack a g e suited for foods where packaged appearance is important. CÏ 2
Further useful i n f o r m a t i o n on k e y e d C h e m i c a i items m e n t i o n e d is r e a d i l y a v a i l a b l e . . . Use handy coupon on page 7936 ^
1930
CSE1N A P S U L
16.
Ϊ 956
