CHEMICALS
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Low rebound is necessary for crash padding to eliminate any possible neck snap. A change in urethane foam formula can considerably decrease resilience of the material. Resilience properties of various cellular foams are here com-
Crash Padding from Castor Oil Castor-based polyurethanes with modification should prove a boon to low-cost safety for Detroit
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ACS NATIONAL MEETING
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S ting to automotive manufacturers is r e-e m p h a s i z e Paint, Plastics, safety. Various & Printing Ink materials are now (llefnistry used as crash padding: foam rubber, vinyls, and polyester-based urethane foams. M. E. Bailey, of Allied's National Aniline Division thinks suitably modified polyurethanes based on castor oil will provide the answer at low cost. Noting that blows to the head are generally the most serious, Bailey cites five general padding requirements. The material should: •Have low density. •Be thick enough so the head doesn't bottom. •Not let the head decelerate too fast. •Give a peak force less than 50 times t h e head's weight. •Recover slowly. He told the Division of Paint, Plastics, and Printing Ink Chemistry that low density, rigid cellular plastics absorb shock almost ideally. Actually, rigid polystyrene foam is used as a 84
C&EN
SEPT.
23,
1957
pared by photographing the height a metal ball rebounds when it is dropped from an equal height on blocks of the foams. The foams (left to right): latex; vinyl; and polyether, polyester, and castor oil urethanes
reference standard in crash pad tests. However, the blow destroys them so they're good for only "one-shot" service. Even so, polystyrene is receiving increased attention in specialized safety use, such as auto racer crash helmets. • Big Automotive Markets. Slow recovery is best; this means that after the impacting object is removed, the dent in the pad must be visible. In one major use, gymnasium equipment, this presents no problem, and Bailey sees it as an almost-immediate market. However, the big potential outlet is automotive crash padding. Here Bailey notes that engineering safety notwithstanding, automotive designers want quick recovery, preferably immediately. Obviously, this means danger of neck snap injury. Designers and engineers are compromising and heading for an almost, but not quite, immediate snap-back. One direction in which Bailey's staff now works is combining glass fibers with the castor-urethane foams. Scientists feel low rebound will satisfy safety engineers, and prompt return to original form will satisfy designers. Straight castor oil-isocyanate foams, using conventional plasticizers, initially absorb shock well. However, the plasticizer migrates, and Bailey notes the foams do poorly upon aging. When castor oil is used as both polyol and plasticizer (in a three-step reaction with tolylene diisocyanate), resulting foams keep physical properties upon environmental aging, and have necessary low resilience.
Bailey expects big things from polyurethanes in the automotive field. With further development he thinks the glass-modified, castor oil-polyurethanes could be important.
Need a Portable Oxidizer? Perchloryl fluoride is stable a n d noncorrosive but packs lots of oxidizing p o w e r
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A new inorganic fluorine compound with properties pointing to a variInorgank ety of novel uses is Chemistry now being produced in ton quantities by Pennsalt Chemicals Corp. Perchloryl fluoride, C10 3 F, is a stable gas which is inert and not corrosive at room temperature. It is a powerful oxidizing agent at higher temperatures. Its physical properties compare with ammonia's, its chemical properties, those of oxygen. John F. Gall of Pennsalt told the Symposium on N e w Inorganic Chemicals sponsored by the Division of Inorganic Chemistry that perchloryl fluoride stored as a liquid in an ordinary steel pressure vessel is "a convenient, portable, and compact liquid oxidizer." The oxidizing properties of the compound may mean its use to store energy in chemical form. Possibilities: in portable metal cutting and welding ACS
NATIONAL MEETING
New Text Matheson's complete line of high-precision controls and accessories was developed as a result of our working experience with all types of compressed gases. These controls and accessories are designed for maximum efficiency, safety and accuracy in handling various types of gases. They are corrosion resistant, easy to use and attach directly to the cylinder. Matheson controls and accessories are described in our Gas Price List. Why don't you check it today, or write our Engineering Department for further information ? AUTOMATIC REGULATORS — Single and 2-stage with flow control valves on outlet. Delivery pressure ranges up to 1000 p.s.i. NEEDLE VALVES — Fingertip control for flow rates from a few cc. per minute to rapid flow. MATHESON' FLOWMETERS — A new concept in laboratory flowmeter use, eliminating the need for physical calibration of different gases. ALSO SPECIAL VALVES, MANIFOLDS, H I G H PRESSURE FLEXIBLE HOSE, QUICK-COUPLERS, GAUGES AND S P E CIAL ACCESSORIES.
Described in our latest Gas Price List. Write for your copy. 76 Compressed Gases plus Custom mixtures.
New Compressed Gases and Regulators
Text East Rutherford, N. J.; Joliet, III.; Newark, Calif. SEPT.
23,
1957
C&EN
85
NDUL I
®
Superior
Phenolic Resins
imparts highly desirable properties, effects substantial savings With resins used for paper sheet sat- with either acid or basically catalyzed uration, use of I NDULI N produces a stiffer board of superior machinability. When such board is used as punching- stock, crispness of the punch is greatly improved, cutting tool life considerably extended. Replacing 50r'r or an even greater percentage of resin normally used for saturation, INDULIN, at 7
