Document vVvEdGryGjw67w1JN5nL9rwxw

26 Lina PE Basin Investigation L-61 to. J. W. Iliff, Lab. ' H* &<p Young* Lab. BEIlfi10 MARSHALL LA8O8AIO0! LIM Philadelphia Laboratory ran 4, 1946 MEMORANDUM REPORT #M-58 "INDEXEDl9? Je25'53 * . . IlfllllCI c; *DBLt?Xw HEAT RESISTING GRAY 28-1W R CIMIMIOIf This memorandum will report the results of formulating work to remote soya bean oil "DUHJX" resin from 28-443 8-h Heat Resisting Gray paint sold to The Texas Company. Heat Resisting Gray 28-443 is semi-gloss product based on 33 Line mill bases let down with RC-193, 62$ soya bean oil KDULUX" resin. It is designed to withstand tempera tures up to 50QF. The following resins were tested as repleoeaents for the RC-193: RC-141 - 62$ Linseed Oil Resin RG-203- 52$ Linseed Oil Resin PSC-P-36983 - 63$ Linseed Oil Pentaerythritol Resin The latter resin provided the best balance for gloss, hardness and drying time. The RC-141 returned definitely poorer hardness, while RC-203 provided poorer gloss. All the substitute resins were equally badly discolored in the five hour at 500F. heat resistance test and retained excellent adhesion. The formula based on PRC-P-36983 was assigned the code 28-679. This product dried very slightly slower than 28-443, had equal gloss, slightly better hardness after overnight drying and equal heat resistance. In connection with the above reformu lation, the pigmentation was revised to use the preferred grade of titanium dioxide pigment . The formulations discussed above can be found in Mote- book 3006, pages 88, 89, 130, 131. ` ' ' PHILADELPHIA LABORATORY VBOsFBH Y, R. OLSON