EPOXY PERFORMANCE IMPROVED BY CAREFUL CHOICE OF CURING SYSTEM As epoxies continue to gain popularity, increasing emphasis is being placed on tailoring their cured properties to specific applications. This calls for precise evaluation of curing systems. As the producer of a number of curing agents, we'd like to do our bit to clarify the picture. The most popular Pennsalt curing agents are our S-l (Dimethylaminoethanol, also known as N,N-Dimethylethanolamine), S-2 (Diethylaminoethanol), Triethylamine and n-Butylamine. These are usually combined with polyfunctional agents (polyamines, polyamides, and others) for atmospheric or mild heat cures, but may be used alone in some cases.
For high temperature cures, they may be used in small amounts with anhydrides. Pennsalt S-l and S-2 are outstanding, even in low concentrations, for their ability to reduce the viscosity of resins and viscous curing agents. S-l speeds curing when used with polyamines, polyamides or S-2. It improves acid, alkali and water resistance, and pigment or filler wetting in highly loaded systems. Use of S-l in curing systems for special polyamide structural formulations increases heat distortion temperature. In low temperature curing with polyamines, it reduces sweatout or "blushing" of the polyamines.
S-2 delivers the same general advantages of S-l, especially if post curing is employed. In addition, it provides low exotherms when used alone, and is valuable in anhydride curing systems, where it provides good pot life along with high temperature acceleration. To shorten curing time of straight S-2 systems, heat or S-l as an accelerator can be used. Triethylamine may be a good choice where you want a slow, low exotherm cure. You can get such cures at room temperatures with an accelerator, and without one in some cases. If impact resistance is a key property, consider n-Butylamine. This interesting agent functions as a flexibilizer, and reduces the crosslinking potential of polyfunctional catalyst systems. This capsule summary, needless to say, hits only the high spots. For more details, write for Bulletin S-l45. Flow-improving ability of Pennsalt Curing Agent S-l is illustrated by samples of cured epoxy resins shown at left. All samples used same sand-type filler. Center tile used only diethylenetriamine as curing agent. Smooth finish of tile at left was produced by substituting small amount of S-l. Addition of pigment with S-l produced dark (red) tile at right.
TRY ALKYL ALKANOL AMINES FOR LOW-TEMPERATURE POLYURETHANE CURES If you're looking for a more effective activator for curing reactive polyurethanes at room or atmospheric temperatures, you may find it profitable to take a close look at the alkyl alkanol amines. Pennsalt Dimethylaminoethanol (N,N-Dimethylethanolamine) and Diethylaminoethanol are currently popular because of their combination of tertiary amine and hydroxyl functional groups. The alkyl di-alkanol amines, with their two active hydrogens, also look promising, since they can act as both cross-linking agents and catalysts. Another feature of the alkyl alkanol amines is the incorporation of additional nitrogen into the polymer, providing a cationic site that could be advantageous. Alkyl alkanol amines can be used with an organo-tin or an all-amine
accelerator, in one-package or twopackage systems. They are applicable to all reactive polyurethanes, whether based on polyesters, polyethers or other materials. Pennsalt's broad line of lower alkyl alkanol amines enables you to select the one that performs best in your system. Well be glad to send you a complete listing, with condensed technical and shipping data, and to supply evaluation samples. Just drop us a note asking for Bulletin S-161. Other Pennsalt products for polyurethane producers include Isotron® fluorinated hydrocarbon foam-blowing agents, which deliver a number of attractive advantages. You can get an informative bulletin, "Blowing Foams with Isotron", by writing to our Isotron Chemicals Dept.
PENNSALT DEVELOPMENT CHEMICALS Dl TERTIARY NONYL POLYSULFIDE (TNPS) Courtesy Universal Oil Products
HF OFFERS ATTRACTIVE ECONOMIES AS CATALYST Anhydrous hydrofluoric acid delivers outstanding performance as a catalyst in a number of reactions leading to the formation of new carbon-tocarbon bonds. These reactions function by the formation of organic fluorides or H F complexes, which act as intermediates. The acid comes through in its original form with the reaction products, and can be recovered. A familiar example of these carbonto-carbon bond formation reactions is the alkylation of isoparaffins with olefins to make isooctane for hightest aviation gasoline. In addition, H F has been used to effect the polymerization of amylene, butadiene, styrene, thiophene, thianaphthene and other compounds to yield very high molecular weight products. H F offers distinct advantages that give it the nod over other catalysts for such reactions. These include:
Efficient catalyst recovery — Since AHF boils at 67° F at atmospheric pressure, it can be recovered easily and economically from less volatile materials, such as C 3 and heavier hydrocarbons, and from contaminants by distillation. The recovered A H F can be recycled to the process, greatly reducing acid disposal problem. Simplified cooling—The H F alkylation process operates successfully at temperatures well above those required by other catalysts. Cooling can be accomplished with water, often eliminating the added expense of refrigeration equipment. To help you take advantage of HF, Pennsalt provides expert technical assistance based on over 40 years of experience in producing, shipping and handling this versatile chemical. Write for our H F Data Book S-148, or discuss your requirements with your Pennsalt representative.
CANDIDATE FOR NEW USES • As a rubber vulcanizing agent • As a softener for rubber and rubber substitutes • As a diesel oil improver • As a sulfur donor for sulfuration of organic compounds
Pennsalt TNPS . . . a l r e a d y used extensively as an extreme pressure a d d i tive in cutting oils . . . offers properties that suggest entirely new fields of application. This clear, straw-yellow, oily liquid has oil solubility and high active sulfur. Its properties include: Molecular Weight (calc'd) 414.8 Total Sulfur 3 6 . 5 % min.
(38.6% calc'd) Active Sulfur 2 7 . 5 % min. Specific Gr. @ 2 0 ° C . . . . .1.036-1.045 Flash Point 330°F Odor faint, mild hydrocarbon
Pennsalt Chemicals ESTABLISHED 1850
Industrial Chemicals Division PENNSALT
CHEMICALS
Literature and samples on request. CORPORATION
T h r e e P e n n C e n t e r • P h i l a d e l p h i a 2 , Pa.
MARKET DEVELOPMENT DEPARTMENT PENNSALT CHEMICALS CORPORATION THREE PENN CENTER • PHILA. 2, PA.
