Document NbwrdEgVYMBjXj39bnJDabyb

SPECIALTY MARKET BUILDERS (from Monsanto) AROCLOR* ...key to lower-cost, fire-resistant, job-tailored epoxies! Forniulators andusers alike have alter nately sung lyrical praises and grow led ever the fast-setting, tight-bonding, rock-hard epoxies. Chief reasons for the praise have been the resins' fan tastic impact strength, their chemical resistance, their versatility of appli cation--from the making of plastic metal-stamping dies to tank linings and body solders. The growls stem from their cost, from 60 to 70 cents a pound, and because the resins burn lustily--a distinct drawback in certain applica tions, such as laminates for electrical uses. Flameproofing curing agents and resins runs the cost still higher. But now a series of property-modifying, low-cost chlorinated polyphenyls has comeforward to make epoxy resinfor mulations both fire-resistant and sig nificantly cheaper by the pound. In these flame tests, one epoxy strip ignites nd burns rapidly; the other, containing Arodor. won't ignite at all. The several hundred specialty formttlators of epoxy resins (as well as the seven basic manufacturers) have un covered t* way to "job tailor" epoxies. The method is simplicity itself: just mechanical mixing into the formula tion of the right amount of a selected chlorinated polypheny!. The chlorin ated polyphcnyis, supplied by Mon santo under the registered trademark Aroclor, "adjust** the uncured epoxy formulations' viscosity, and the cured resins' hardness and flexibility. Most important--the addition of an Aroclor makes the epoxy formulation cheaper per pound and fire-resistant. The Arcelor compounds, it proves out, are one of the very few materials compatible with epoxies. And, hap pily, they come as a series of some dozen liquids and solids that range from water-white mobile "oils" and clear, viscous resins to bright, paleyellow solids resembling a good-color rosin. Chemically, the materials are progressively chlorinated di- and polyphcnyis--each containing a def inite percent-by-weight ofinert, tightly bound chlorine. The Aroclor compounds are some of the most inert, chemically stable com pounds in industry. They are imper vious to heat, acids, alkalis, and they are among the most ignition-resistant compounds commercially available. Most important, they are cheap--in the carload range of 16 to 19 cents per pound. When added to epoxy formulations, the liquid Aroclor com pounds function as low-cost plasti cizers: the solids, as reinforcing resins. Since the mobile "oil-y" forms can be mixed in any proportion with the viscous and solid resin forms, the Aroclor compounds give the epoxy formulator a perfectly gradated vis cosity range of "diluent" that can plasticize or reinforce, that cuts costs, and imparts Are resistance. With epoxy usage now in the 60-70 million pounds per year range, it is estimated that forniulators supplying rcady-to-usc resins for about one third of the applications can significantly improve their offerings (and lower materials costs) with the use of this new technique. When used in the range of 15 to 20 parts per hundred, the Aroclor compounds greatly re tard the epoxy's burning rate, and proper selection of the Aroclor com pounds can impart variously: im proved flow, belter flexibility after curing, and better flexural and com pressive yield strengths. Since live of approximately a dozen Aroclor compounds provide a fivestep variance in viscosity--ranging from almost water-like liquids to solid resins with a softening point of about 300 P.--the range of modification possible for any particular epoxy for mulation is enormous. For example, solid Aroclor 5460 used in the amount of 15 PHR (plus 5 PHR of antimony oxide) acts as a reinforcing resin and produces a nonburning compo sition. The cured resin compares in "strengths'* to an identical control without Aroclor and antimony oxide as follows: IS PHR Ciotrot Aroclor 5460; $ PHR tttimonjf oxide flex Strength.......... 16,900 psl 19,000 psi Tensile................... 11,000 psi 10,200 psi Compressive Ultimate Strength 23,400 psi 40,700 psi Hardness (RockweU"M") 111 111 Heat-Distortion Temp., =C............. 143 13S Burning Rate (ASTM 635-56T)-- .6in./min. nonburning The lovv-moiccular-vveight liquid Aroclor compounds show a definite plasticizing effect. With liquid Aroclor additions,"the heat-distortion temper ature is somewhat lowered; the solids, on the other hand, show- little sig nificant effect on the heat-distortion temperature. Depending upon the ultimate use of the epoxy formulation, producers will have to work out their own recipes. Hundreds of modifications arc possi ble with "amine"-type cures and also with a "phthalic anhydride" cure. The nonburning benefit of adding Aroclor and antimony oxide should prove particularly valuable in laminates for printed circuits and other electrical uses. The modification of handling properties, the reinforcing effect, and the maintenance ofexcellent chemical resistance should have application in adhesives, surface coatings, encapsu lation compounds, plastic stamping dies, and body solders. And the cost savings can hardly fail to catch the interest of all epoxy formulators. For further information on de veloping lower-cost nonburning epoxy formulations, request a copv of Specialty Data Report CS-14: "AROCLOR. FircRetarding Plasticizers and Mod ifiers for Epoxy Resins." Ad dress your request to Monsanto Chemical Company, Organic Chemicals Division, Depart ment 4430Y, St. Louis 66, Mo. 61-OMC-M30 Chemical Week, January 28, 1961. TOWOLDMON0047974 WATER PCB-00035193