IhTD USTRIAL AND ENGINEERIAYG CHEMISTRY
January, 1929
and used in the construction of this diagram, they would probably appear as those in Figure 5 and would depict a solid representation, such as is shown in Figure 6. Only latent heats of transformation are represented by this solid figure, and, if changes of heat content in the various stable states were shown, the diagram would become very complicated. A model of the type shown in Figure 6 aids the interpretation of the system in a clear-cut manner. For example, pure silica would cool from the liquid to the solid state (as cristobalite) a t 1710" C., with a loss of heat as shown by a drop to a lower plane in the solid figure. The cristobalite so formed loses some heat down to 1470" C., where the change from cristobalite to tridymite is shown as a drop to a still lower level of heat content; another drop, which is not shown here, would occur a t the transformation of tridymite into quartz. The high and low forms of these various stable types of silica as discussed by Sosman would make this side of the solid figure extremely complex.
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Pure fayalite and ferrous oxide would drop directly from high to low levels of heat content upon solidification. Intermediate compositions would drop to lower levels in various manners. Also, solid fayalite would have a higher heat content than either pure solid silica or ferrous oxide, and it is thus shown. The diagram, the probable cooling curves, and tke solid representation have all been constructed under the assump tion that the most stable phases of silica exist a t their various temperatures. Equilibrium cannot be otherwise expressed. With pure silica, cristobalite is shown to exist between 1710" and 1470" C., where the transformation to tridymite occurs, and tridymite is the stable phase from 1470" to 870" C. At 870" C. tridymite changes to the quartz phase, which is the stable form a t room temperature. These transformations are only possible through prolonged heating a t the various temperatures, and, although they probably do not all occur in the ferrous silicates under discussion, they do represent equilibrium.
A Light-Colored Condensation Resin' H. A. Gardner, C. A. K n a u s s , a n d A. W. V a n Heuckeroth GARDIBP LABORATORY, INSTITUTE
O F P A I N T AND V A R N I S H R E S E A R C H , W A S H I N G T O N ,
D"
.RIIiG the last few months several new synthetic resins of the "phthalic" type have made their appearance. According t o some of the patent claims, these resins are produced by the condensation of molecular proportions of glycerol and phthalic anhydride, together with certain organic acids, such as butyric, succinic, malic, citric, fumaric, oleic, linseed, and tung oil acids, or with castor oil. We have prepared resins in which the glycerol has been replaced by another polyhydric alcohol. Such alcohol has been condensed with phthalic anhydride and aliphatic hydroxy mono- and dibasic acids. By the elimination of two molecules of water from three molecules of glycol, a polyglycol, known as triethylene glycol, is formed. This compound, which has the formula H O C H L -CH2-CH20H, has a boiling point CH2-O-CHLCH2-0 of 278" C. It apparently possesses several desirable properties for a resin base. It has two hydroxyl groups with a long chain separating them so that if formed into a resin it should possess good plasticity. It also has a comparatively high boiling point, so that the reaction of formation may take place a t a relatively high temperature without danger of loss by evaporation. Triethylene glycol prepared as above was heated with phthalic anhydride and tartaric acid. A soft liquid resin was produced. Combining this with cellulose ester gave a lacquer which formed durable iilms without any added plasticizer. Apparently resinous products of the type produced by these reactions act as both resins and plasticizers when used in cellulose ester lacquers. M e t h o d of P r e p a r a t i o n
One mol (148 grams) of phthalic anhydride and one mol (150 grams) of triethylene glycol were heated together a t 110' C. for a half hour. The temperature was gradually raised to 175-180O C. and held until evolution of gases had ceased. Then the temperature was raised to 200-210" C., and 1mol (140 grams) of tartaric acid was added. A temperature of 185-200" C. was maintained for several hours. If 1 Received
August 31, 1928.
D. c.
the resin is allowed t o cool after heating for about 3 hours, i t is of a pale amber color and is in the form of a viscous solution soluble in acetone, alcohol, and chloroform, but insoluble in toluol. It is quite compatible with nitrocellulose solutions. If the heating is continued for 15 to 18 hours, a dark amber plastic mass is produced, which is incompatible with nitrocellulose solutions but compatible with cellulose acetate solutions. During this continued heating the acid number is not materially dec r e a s e d , so that the change must be one of polymerization r a t h e r than of condensation. These resins will not f o r m solids either by baking for several hours or by heating u n d e r pressure. Apparently they are true l i q u i d resins. It will be noted that the resin may be produced in a form that is compatible with cellulose a c e t a t e or in a Figure 1-Illustration of C l a r i t y of a Light-Colored R e s i n form that is Printing upon paper placed a t bottom of with nitrOCellUlOSe. a friction can cover is readily discerned As very few resins are through a layer of resin about 5 mm. in depth. compatible with cellulose acetate, this resin might prove especially desirable for use in cellulose acetate lacquers. In an exposure test on nitrocellulose or cellulose acetate, lacquers containing as high as equal parts of the resin to the cellulose ester used were exposed upon iron panels for several weeks with fairly satisfactory results. Regulation of the use of spray painting by compressed air machines, by common carriers, and employees of Federal agencies is proposed in a bill (H. R. 15,385),which was introduced in the House of Representatives December 14 by Representative Zihlman and referred to the House Committee on Labor.
