INDUSTRIAL AND ENGINEERING CHEMISTRY
2292
(27) Faith, W. L., Keyes, D. B., and Clark, R. L., “Industrial Chemicals,” New York, John Wiley &T Sons, 1950. (28) Food Engr., 23, No. 9,83-5, 179 (1951). (29) Furtune, 43 No. 6 , 9 3 (June 1951). (30) Fritts, H. W., and Verink, E. D., Jr., IND. ENG.CHEM.,43,2197 (1951). (31) Gresillon, R., Rea. ahmiiiiunz, 28, 18+7 (May 1951). (32) Nartmann, E. C., and Plummer, F. L., Civil Eng., 22, 123-5 (1952). (33) Hoglund, G. O., Welcliw J . ( N . Y . ) 30, , No. 4, 331-46 (1951). (34) Iron Age, 168, No. 5,104 (1951). (35) Ibid., 168, NO. 14, 318-20 (1951). (36) Juniere, P., Aluminium SzLisse, No. 5, 163-72 (September 1951). (37) Kelly, R. C., Heating, Piping, A i r Conditio?ting, 24, No. 1 , 124-9 (1952). (38) Lawrence, S. M., I d . Cheniist, 27,219-24 (1951). (39) Lee, J. A., “Materials of Construction for the Chemical Process Industries,” New York, McGraw-Hill, 1950. (40) Lees, D. C. G., Light Metals, 14, No. 162,494-502 (1951). (41) Light Metals, 14,229-31 (1951). (42) Ibid., 14, NO. 163, 541--6 (1951), (43) Ibid., 14, No. 164, 639-43 (1951). (44) Ibid., 14, NO. 165,662-7 (1951). (45) Loo, K. J. van de, Polytech. Tijdsehr., 7,Y-lOa (Jan. 8, 1952). (46) McConomy, H. F., and E n r , J. J., Petroleum Refiner, 31, No. 5, 124-6 (1952). (47) Manning, Q. P.,Civil Eng. Public Works Rm., 47, 547 (1952). (48) Modern Melals, 7, No. 9, 25 (1951). (49) Moore, W. B., Jr., Petroleum Engr., 24, No. 4, D28, 30, 32 (1 952). (50) Nucleonics, 10, No. 6 . 75-6 (1952).
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(51) Ibid., p. 96. (52) OiZGasJ.,50, No. 11, 122 (1951). (53) Petro Times, 54,320-3 (May 5 , 1950). (54) Picarazzi, J. J., OaZ Gas J . , 50, No. 45, 271-82 (1952). (55) Plant Eq.n ., 6 , No. 4, 38-9 (1952). (.56) Pogacar, C. F., and Tice, E. A., Corrosion, 7 , No. 3 , 7 6 4 4 (1951). (57) Rabald, EI ich, “Corrosion Guide,” Amsterdam, Elsevier Publishing Co., Inc., 1951. (58) Reichert, J. S., and Pete, R. H., Chem. Esag., 58, KO,10, 263 (1951). i59) Riesenfeld, F. C., and Blohm, C. L., Petrotezrm Refiner, 30, No. 2, 97-106 (1951). (60) Schueler, R. C., Corrosion, 7, No. 7, 6 (1951). (61) Shearon, W.H., and Thompson, H. L., 1x1).ENG.CHEW.,44, 254-64 (1952). (62) Shepard, S. VI.,Corrosion, 7, No. 8, 279-82 (1951). (63) Soldmann, D., Milk Plant Monthly, 40, No. 10, 88 (1951). (64) Wanderer, E. T., paper presented at the 8th Annual Conference of the N.A.C.E., March 1952. (65) Wanderer, E. T., Oil Gas J.,50, KO,9, 58-9, 76 (1951). (66) West, J. R., Chem. Eng., 58, No. 9, 276 (1951). (67) Whitabet., AI., MetuZInd., 80, No. 10, 183-6 (1952). (68) Ibid., NO. 11, 207-12 (1952). (69) Ibid., NO. 12, 227-30 (1952). (70) Ibid., NO. 13, 247-51 (1962). (71) Ibid., NO.14, 263-6 (1952). (72) Ibid., NO. 15, 288-9 (1952). (73) Ibid., NO. 16, 303-5 (1952). (74) Ibid., No. 17, 331-2 (1952). (75) Ibid., No. 18, 346-9 (1952). (76) Ibid., S O .19, 387-8 (1952). RECEIYBD for review July 21, 1952.
ACCEPTEDJuly 21, 1952.
CEME
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K. PAYR‘E,
E l e c t r o C h e n t i c a l Engitieering & M a n u f a c t u r i n g Co., 750 Broad S t . , Emmalrs, P a .
acid has been found to be an excellent Condensing agent, resulting in a product of good strength but free from acid-diffusion difficuli,ies encountered with other acidic reagents. Bromine also has advantages a condensing agent. Products having flexural strengths UP t o 3800 pounds per square inch havc bcen produced. One mch cement has the unusual property of polymerizing at room tenrpeiature with an alkaline catalyst. This makes it possible t o bond a rwin cement directly t o alkaline surfaces such as concrete and has resulted in several important industrial applications. h o t h c r cement from this group has greater resistance t o oxidizing acids and sodium hypochlorite than either the furfuryl alcohol or phenol-formaldehyde resin cements. A lower cost is a further possibility, since furfuryl aldehyde is l e s espensive than furfuryl alcohol. Improvements havc been made in Eurfu~ylalcohol cemcnts used for the impregnation oi wood (19). In a filter press handling acids and alkalies, half of the plates and frames were made of wood impregnated with furfuryl alcohol resin cement at room temperature under a pressure of 100 pounds per square inch. The other half n/as not treated. At the end of 1 year the untreated wood had disintegrated to the extent that the plates and frames were discarded. The impregnated plates and frames are still in excellent condition a t the end of 14 months. A furfuryl alcohol resin composition that is satisfactory for impregnating plaster has been described (16). Flexible filter grids made of furfuryl alcohol resin cement reinforced with glass cloth have been under test in a pigment plant and have proved superior t o TTOOd.
Acidproof brick linings continue to use by far tlir greatest tonnage of acidproof cements. Several other important industrial applications have been developed, A successful techdque has been developed for impregnating w o o d with furan resin cement which has increased the life of wood filter-press plates and frames. Filter grids, fabricated from glass clo th-reinforced €uran resin cement, have high strength, light weight, desired flexibility, and chemical resistance. Large diameter steel covers for chemical process equipment have been satisfactorily protected from hydrochloric acid and chlorinated solvents by reinforced furan resin cements. New high solids neoprene cements cut labor costs in tank linings,
A
Vol. 44, No. 10
NUMBER of new industrial applications in chemical plants
have been developed in which various types of ncidpioof cemmts have been used FURAY KSSIN CEMEWTS
Cntil recently most of the furan resin cements used in the constiuction of chemical equipment were based on resins obtained by the acid polymerization of furfuryl alcohol or furfuryl alcoholaldehyde condensation products with or without other materia1,i that inay be considered as additives. Within the pa& 2 years a t least two chemical-resistant cements, mhich are based on furfuryl aldehyde condensation products, have been placed on the market. When furfuryl aldehyde is condensed alone by means of acids, the product is a weak porous substance. The effect of various additives on the strength properties of a cement based on the polymerizing tendencies of furfuryl aldehyde has been studied ($9, 41, 85). It has been found that among suitable additives are secondary aromatic amines, certain furan derivatives such as furfurin, methylfuran, furfural acetone, 2,5-dimethylfuran, and furfuryl acetate, and ligninsulfonic wid with one of the other additives. p-Toluene-
October 1952
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INDUSTRIAL AND ENGINEERING CHEMISTRY
2293
As reported in the formaldehyde a n d urea-formaldehyde previous annual reresins. This material view, furan resin ceis used as a filler in ments have been deliquid resin to form a veloped which have a shrinkage on setcement which sets a t ting of less than 0.1% room temperature. Ammonium chloride and a coefficient of thermal expansion is used as a setting agent. One advanwhich closely aptage reported is that proach- that of steel a thick joint can be over a temperature used without danger range from 20' to of c r a c k i n g (8). 250" F. Using these Phenol-formaldehyde m a t e r i a 1 s, 8 t e e 1 covers for chemical cements can be modiprocess tanks subfied with alkyd-sulfonamide-aldehyde jected tohydrochloric acid and solvents at resins without lower230' F. have been ing chemical resistWood Plates and Frames i n Filter Press Subjected to Acids, Alkalies, s a t is f a c t or il y proance (81). A new and Solvents Are Impregnated with Furan Cement tected by welding resin h a v i n g t h e Floor under press constructed of acidproof brick joined with furan cement metal mesh to the novel property of steel cover and then being l i ~ h tin color troweling the resin cement into the mesh. Final protection is is produced from phenol, furfuraldehyde, and formaldehyde (64). obtained by a glass cloth-reinforced layer of resin. A new acetone-formaldehyde resin cement has been developed Flat sheets and reinforcing angles have been formed at room for bonding laminated products (3, 50). A room-temperature temperature from furan resin cement reinforced with glass fiber setting cement satisfactory for chemical construction is made from a n alkali-polymerized phenol-formaldehyde liquid resin (IO). Fume ducts, small tanks, and launders have been fabrimixed with carbon and phenol-sulfonic acid as a setting agent cated on the job site by sawing the sheets and angles to the dosired dimensions. The angles me used t o reinforce the corners (49j. Modified phenol-formaldehyde resin compositions are deand are cemented t o the sheet with the furan cement which sets scribed which have increased resistanae t o alkalies and inat room temperature. Tests show the sheets and angles t o have a creased adhesion t o metals (90). It was found that the addiflexural strength of 11,210 pounds per square inch, a tensile tion of aniline-formaldehyde resin t o phenol-formaldehyde resins strength of 2,920 pounds per square inch, an impact strength in approximately doubled the lap-joint strength for laminated foot pounds per inch notch on '/*-inch thick specimen on edge of wood (16). A cement having increased resistance t o temperature is produced from alkylated phenol orthosilicates and form2.73, a deflection of 0.151 inch, and a water absorption of 0.51. A shear test on two sections cemented together showed the bond aldehyde (38). By blending a copolymer of butadiene-acryloto be stronger than the sheet material (60). Furan cements can nitrile with phenol-formaldehyde resin, aluminum metal. be produced having low or high electrical resistivity, varying and a setting agent, it is reported t h a t a cement is produced from 4.42 ohm-cm. t o 254 megohm-cm. Submersible batteries that will adhere glass t o steel with a bond of 4000 pounds per equipped with leakproof plugs are sealed at the top of the consquare inch (61). tainer with a furan cement capable of maintaining the seal when subjected t o an internal pressure of 4 pounds per square inch S U L W R CEMENTS throughout a temperature range of -65" t o ZOO" F. OutstandThe proposed specifications for sulfur cements were adopted ing performance has been obtained in tanks, communication equipment, and trucks under rugged battlefield conditions (79). a t the annual meeting of the American Society for Testing Materials in June 1952. These proposed speciiications have ASTM Partially resinified furfuryl alcohol polymers on hydrogenation designation C-52T and list minimum requirements of physical form a plasticizer compatible with furan resins (18). and chemical properties along with methods for testing. Two new patents have been issued on the manufacture of furA mixture of polyalkylene polysulfide resin, halogenated furyl alcohol resins for use in cements (66, 86). Furan or other rubber, and maleic anhydride-rosin addition product is used for organia cements should not be used in contact with chlorine dioxbonding vulcanized or unvulcanized polysulfide rubber in fabriide (85). cating self-sealing gasoline tanks (96). A stripping agent is described for removing polysulfide elastomer cements from fuel PHENOLFORMALDEHYDE RESIN CEMENTS and oil tanks (26). A new series of resin cements has been produced by blending epoxy resins with modified phenol-formaldehyde resins i S 4 ) . SILICATE CEMENTS These resin cements have unusual properties. Unlike the usual The use of various types of silicate cements for the protection phenol-formaldehyde product these cements have excellent resistance t o alkalies and t o nitric acid up t o 15% concentration, of metal surfaces has been given in a detailed report (17). Cofferdam leaks were stopped by using a silicate cement with calmay be stored for 12 months or perhaps longer without danger of loss by polymerkation, and have greater plasticity and adcium chloride as a setting agent (63). By this method, the soil was cemented into a soft sandstone that was impervious t o water hesion to metal surfaces They have been used t o line tank cars handling strong caustic and t o join brickwork exposed t o under a considerable hydrostatic head and with a bearing strength dilute nitric acid, which would attack the usual phenol-formalup t o 50 tons per square foot. An acid- and oil-resistant cement dehyde cement. is produced from sodium silicate, rubber latex, and sodium silicoA phenol-formaldehyde cement for bonding wood has been fluoride as a setting agent (6). A chemical grouting material of a sodium silicatesodium aluminate composition is reported described. Wood meal is impregnated with a blend of phenol-
2294
INDUSTRIAL AND E N G I N E E R I N G CHEMISTRY
,(36). Ethyl silicate mixed with dilute hydrochloric acid as a setting agent is said t o form an excellent heat-resistant protection for aluminum or steel (89). Sodium silicate mixed with asphalt emulsion and a setting agent is used for coating lead-covered cables to prevent corrosion in certain types of soil (66). HYDRAULIC CEMENTS
A detailed study of the use of calcium chloride in concrete indicates that when used in amounts u p t o 2y0 it is beneficial. Advantages include early strength development, greater resistance to abrasion and erosion, and special benefit t o concrete exposed to low temperatures (76). A composition consisting of portland cement, copper oxide, and calcium chloride is reported to have high strength, be sparkproof, and not support fungus growth (1). An investigation of t h e use of fly ash in concrete showed t h a t i t reacts with lime liberated during hydration t o form B more stable cementing medium (7). Barytes aggregate produces a concrete for nuclear shielding provided it is not submerged in water or exposed t o continuous heavy washing (88) Aluminous cement is reported to be sathfactory for handling dilute mid effluent8 with a pH of 4.5, while high sulfate cementa are more effeetive for effiuenta with a pH of 3.5. Rubber latex added to jointing cements improves chemical resistance (26). During the past year there has been increased interest in cements made by mixing latices of natural rubber, synthetic rubber, or synthetic resins with aluminous or portland cement, (14, 96, 61, 69). Cements of this type have been widely used in England for joining acidproof brick floors where the floors were subjected %Odilute acids only. Improved chemical resistance is obtained by using synthetic rubber latex. T h e cement bonds well to concrete, and indications are t h a t more of these new materials nil1 be used in the United States. An insulating cement widely used in power plants consists of bentonite, aluminous cement, fly ash, and mineral wool (60). T h e addition of 570of polyvinyl alcohol t o oil-well cement reduces the loss of water in squeeze cementing, and tributylphosphak is used t o suppress foaming (46). A patent has been issued on t h e use of alkali metal sulfonates, water-soluble fluosilicates, and urea sulfate as a concrete hardener (76). A cement slurry for waterproofing concrete and masonry consists of finely divided iron, ammonium chloride, and a water-soluble rellulose ether (47). MISCELLANEOUS CEMENTS
The use of epoxy resin cements continues t o expand (9, 49, 62, 63, 69). These cements may be compounded to set at room temperature or elevated temperatures; they make possible the joining of metals, ceramics, glass, and plastics together and t o each other without the use of pressure. They are used as chemioal-resistant cements, potting compounds for electrical insulation, laminates, and as a coating for lamps t o make them shatterproof. When blended with phenol-formaldehyde resins they impart increased plasticity and chemical resistance. A cement made of dichlorobutadiene and chlorinated lubber Bas been found satisfactory for bonding both natural and synthetic rubber to metals (44). Butadiene-acrylonitrile copolymer latex is reported satisfactory for bonding resinous sheet materials (61). A vinyl cement for repairing seam3 and holes in vinyl plastic products has been developed (23). A composition based on methylstyrene polymer is used for bonding mica (91). Information has been published on the use of urea-formaldehyde cements for bonding wood, polyvinyl formal resina for bonding metals, and isocyanates for bonding metals t o quartz (34). Plating tanks resistant t o acids and plating solutions can be formed of Fiberglas mat that is impregnated and bonded with polyester resin cement (37). A self-sealing insulating cement of high dielectric strength is composed of polyethylene, polyisobutylene, butyl rubber, and phenol-formaldehyde resin (68). A cement having good resist-
Vol. 44, No. 10
ance t o heat and fire consists of a mixture uf poi.ysiloxane, abbestos, refractory powder, and a solvent ( 7 7 ) A hydropolychlorosilyl addition product of rubber is satisfactory far bonding rubber t o glass (4). In the last annual review it was reported that bituminous cements modified with synthetic resins and rubber are being used in large volume for the protection of the outside of chemical equipment. When mixed with lightweight insulating materials such as cork, a weatherproof insulation is produced. The ube of these materials in sulfate paper mills, oil refineries, and chemical p l m t s has been described. Physical and chemical properties along with application details are given ( 3 1 ) . A cold-applied cement composed of asphalt, butadiene-styrene copolymer, and asbestos is used for sealing expansion joints in concrete (84). CHEMICAL RESISTAYCE
The revistitnee of furfuryl alcohol, p~ierrol-forrnaldeh~cle, sulfur, and sodium silicate cements to approximately 200 chemicals has been listed (56,66, 70-73). When using this information it should be realized t h a t corrosion rates in pure solutions may differ considerably from those where small amounts of contaminants are present. R a t e of solution flow and extent of aeration also exert unpredictable effects. Interpolations between the specific ratings given may not he warranted. 1MPERVIOUS ?IEMRHAN:S
The use of both sheet lead and homogeneous lead as an impervious membrane between the supporting structure and the the acidproof brick lining is described (64). Improvements have been made in methods of supporting sheet lead linings, and new methods of testing lead linings and welds have been developed. Homogeneous instead of sheet lead is recommended wherever the vessel is subject'ed t o fluctuating temperatures, high temperatures, vacuum, or vibration. Neoprene cements have proved satisfactory for lining tank cars handling 70% caustic a t 200' F. ($8). A new neoprene cement or coating containing approximately 70% solids has been developed (9). With this material it is possible t o build up a film having from 10 to 15 mils of thickness with each coat, thereby saving labor where thick protective coatings or linings are required. Field results indicate t h a t protective coatings should never be le= than 5 mils thick (68). A floor coating or cement is produced from neoprene latex, sodium silicate, cellulose, and sodium silicofluoride (45). The protection of light structural members is discussed (94). Typical applications of neoprene in t h e chemical industry have been reported (40). Specific data on the compounding of neoprene for maximum resistance t o petroleum gases have been recorded (6). Various mixtures of polyisobutylene and polyethylene have been patented for applications by hot-spraying to concrete or metals ( 6 7 ) . Surfaces having low adhesion t o ice are obtained by coating metal with a polyorganohalopolysiloxane (78). Organosilicon polyesters have proved sat'isfactory for coating hot surfaces such as stacks and furnaces (80). The increasing industrial uses of vinyl plastics as impervious membranes and materials of construction have been listed (12, 39). The fabrication of an impervious membrane made of Kel-F for nitric acid service has been described (11). T h e use of various plastic membranes for tanks, towers, digesters, and reactors has been discussed (28). The chemical resistance of 25 plastics has been tabuIated (69). INDUSTRIAL APPLICATIOKS
The use of acidproof cements for jointing brick linings in digesters measuring 16 feet in diameter by 50 feet high, and cooling towers 16 feet in diameter by 50 feet high are described (855). Either resin cement or litharge-glycerol cement was used throughout this construction. A description is given of a modified chemi-
October 1952
I N D U S T R I A L A N D E N ‘ GI N E E R I N G C H E M I S T R Y
pulp hot-acid recovery system (38). The recovery of waste liquor from ammonium bisulfite pulping is discussed (38). Evaporation and burning in acid-resistant equipment seems to be the most applicable. Carbon linings have been used since 1931 for alkaline pulp digesters. Since that time, 45 carbon brick linings have been installed in all known modifications of alkaline cooking and alternate alkaline and neutral cooking (93). I n some instances hydraulic cements have been used t o join the carbon brick, and it has not been entirely satisfactory. At the present time various types of resin cements are being tested and indications are that certain types of furan resin cements may prove superior t o materials used in the past, The use of acidproof cements and brick linings in chemical plants and,steel mills has been discussed (fa, 97, 49, 48, 67, 7.4, 87). Ceramics based on lithium aluminosilicate have high thermal shock resistance and good chemical resistance a t high temperatures (88). A study has been made of the volume changes in brick linings in steel stacks. Stresses which resulted in failure of welds were not caused by permanent expansion or marked changes in the thermal coefficient of expansion of the lining. Instead, failures originated from transient conditions not anticipated and provided for in the stack design (60). LITERATURE CITED
(1) Avery, S. B. (to Coprox Inc.), U. S. Patent 2,556,156 (June 12,
1951). (2) Bake, L. S., Corrosion, 8, No. 3, 2 (1952). (3) Bakelite Corp., Brit. Patent 649,304 (Jan. 24, 1951). (4) Barry, A. J. (to Dow-Corning Corp.), U. S. Patent 2,557,778 (July 12, 1951). (5) Bergman, I., S. African I n d . Chemist, 2, 11-14 (1948). (6) Bimmerman, H. G., and Shrader, R. E., Rubber India, 3, No. 1, 5-8, 14-16 (1951). (7) Blanks, R. F., J . Am. Concrete Inst., 21, 701-7 (1950). (8) Brookes, Alfred (to British Industrial Plastics, Ltd.), Ger. Patent 803,780 (April 9, 1951). (9) Buck, A. C., and Conlon, J. F. (to E. I. du Pont de Nemours &Co.), U. S.Patent2,569,920 (Oct.2, 1951). (10) Chem. Eng., 58, No. 12, 196 (1951). (11) Chem. Eng. News, 30, No. 26, 2688-91 (1952). (12) Connors, F., Australian Plastics, 7, 10-15 (1951). (13) Cooper, J. E., Iron Steel Engr., 28, No. 11, 81-4 (1951). (14) Cubberly, R. H., and Dill, C. E. (to Patent and Licensing Corp.), U. S. Patent 2,556,575 (June 12. 1951). (15) Dalton, L. K., Fitzgerald, J. S., Tack, G. W., and Tamblyn N., Australian J . Applied Sci., 2, 145-57 (June 1951). (16) Dickinson, T. A,, Org. Finishing, 13, No. 2, 14-16 (1952). (17) Diets, Karl, Werkstofe u. Korrision, 2, 446-8 (1951). (18) Dunlop, A. P., and Stout, P. R. (to Quaker Oats Co.), U. S. Patent 2,564,835 (Aug. 21, 1951). (19) Ibid., 2,584,681 (Feb. 5, 1952). (20) Ferguson, J. W., private communication. (21) Fiedler, L. F., and Leakey, P. J. (to B. F. Goodrich Co.), U. S. Patent 2,575,265 (Nov. 13, 1951). (22) Fontana, M. G., IND. ENC.CHEM.,44,84 A (June 1952). (23) Forte, J. F. (to John Williams Co., Inc.), U. S. Patent 2,553,124 (May 15, 1951). (24) General Electric Co., Bull. CDC-223 (1952). (25) George, M. F., Jr., and Kleber, E. V. (to Lockheed Aircraft Corp.), U. S. Patent 2,548,718 (April 10, 1951). (26) Griffiths, L. H., Chem. Trade J., 129,311 (1951). (27) Griffiths, L. H., Engineering, 172,775-7 (1951). (28) Halls, E. E., Metallurgia, 42,376-81 (1950). (29) Harvey, M. T., and Caplan, Solomon (to Harvel Reseaich Corp.), U. S. Patent 2,516,317 (July 25, 1950). (30) Harvey, M. T., and Rosamilia, P. L. (to Harvel Research Corp.), Ibid., 2,571,089 (Oct. 16, 1951). (31) Henderson, W. W., and Weiler, C. B., Tappi, 34, No. 11, 152A-155 (1951). (32) Hinton, L. G., P u l p & Paper Mag. Can., 52, No. 11, 98-9 (1951). (33) Hirsch, Alfred (to Diamond Alkali Co.), U. S. Patent 2,555,489 (June 5, 1951). (34) Hochtlen, A., Kunststoffe ver. Kunststoff-Tech. u. -Anwend., 41, 53-6 (1951). (35) Hull, W. Q.,Baker, R. E., and Rogers, C. E., IND.ENG.CHEJI., 43, 2424-35 (1951). (36) Imoaka, Minoru, J . Ceram. Assoc., Japan, 59, 497-500 (1951). (37) Jayne, D. W., and Day, H. M. (to American Cyanamid Co.), U. S Patent 2,577,618 (Dec. 4, 1951). ~
2295
(38) Jones, R. M., and Detcher, T. E., Papsr Trade J., 133, No. 5, 20-8 (1951). (39) Kammermeyer, Karl, Proc. Iowa Acad. Sci., 57, 171-80 (1950). (40) Kirchhof, I?., C u m m i u. Asbest., 4,21-4, 51-2, 54, 1 2 1 4 (1951). (41) Kobayashi, Katsuma, Japan. Patent 173,812 (Oct. 5, 1946). (42) Krekeler, K., Plastics (London), 16, 226-8 (1951). (43) Kubota, Masao, and Tsuji, Kozo (to Noguchi Research Inst.), Japan. Patent 172,132 (Jan. 9, 1946). (44) Kuhn, L. B. (to Firestone Tire and Rubber Co.), U. S. Patent 2,581,920 (Jan. 8, 1952). (45) Lewis, E. B. (to Commonwealth Eng. Co. of Ohio), Ibid., 2,567,951 (Sept. 18, 1951). (46) Ludwig, N. C. (to Universal Atlas Cement Co.), Ibid., 2,576,955 (Dec. 4. 1951). (47) Madison,’R. E:, and Fairbrother, A. (to Devoe and Raynolds Co.), Ibid., 2,570,827 (Oct. 9, 1951). (48) Matz, Werner, Chemie Ing.-Tech., 23,543-7 (1951). (49) Meyerhaus, Konrad, Kunststoffe ver. Kunststoff-Tech. u. -Anwend., 41,457-62 (1951). (50) Miller, T. C., Am. Ceram. SOC.Bull., 29, 5 (November 1950). (51) Morris, T. C., and Johnson, E. C. (to B. B. Chemical Co.), U. S. Patent 2,572,879 (Oct. 30, 1951). (52) Moss, C. J., Metallurgia, 43, 267-72 (1951). (53) Narracott, E. S., Brit. Plastics, 24, 341-5 (1951). (54) Novotny, E. E., and Vogelsang, G. K. (to Borden Co.), U. S, Patent 2,566,851 (Sept. 4, 1951). (55) Payne, C. R., IND. ENQ.CHEM.,42,2030-1 (1950). (56) Ibid., 43, 2286-7 (1951). (57) Piatti, L., Schweia. Arch. angew. Wiss.-u. Tech., 17, 80-91 (1951). (58) Pierce, R. R., Chem. Eng., 59, No. 5, 149 (1952). (59) Preiswerk, E., Plastics (London),17, 6-10, 43-6 (1952). (60) Randall, M. C., and Gethen, G. S., U. S. Patent 2,574,843 (Nov, 13, 1951). (61) Redfarn, C. A. (to Durastic, Ltd.), Ibid., 2,581,295 (Jan. 1, 1952). (62) Reichberzer, Richard, Mitt. chem. Forsch.-Inst, I n d . dstew, 5 , 108-10 (1951). (63) Riedel, M. C., Civil Eng., 21, No. 4, 23-4 (1951). (64) Roll, K. R., Chem. Eng., 59, No. 1, 281-90 (1952). (65) Rowland, C. S. (to Interchemical Corp.), U. S. Patent 2,553,677 (May 22, 1951). (66) Sanderson, W. D., Corrosion, 7, No. 11, 1-2 (1951). (67) Schaerer, Andr6, Swiss Patent 271,944 (Feb. 16, 1951). (68) Selby, H. E. (to Bishop Manufacturing Corp.). U. S. Patent 2,569,540 (Oct. 2, 1951). (69) Semtex Ltd.. Bull. 3903 (1950). (70) Seymour, R: B., and Steiner,’ R. H., Chem. Eng., 58, No. 12, 268-84 (1951). (71) Ibid., 59, No. 1, 264-80 (1952). (72) Ibid., 59, NO. 2, 288-304 (1952). (73) Ibid., 59, NO. 3, 268-86 (1952). (74) Shepard, S. W., Corrosion, 7, 279-82, 317-18 (1951). (75) Shidiler, J. J., J. Am. Concrete Inst., 23, 537-59 (1952). (76) Silverman, Isadore, and Moscowitz, Abraham (to L. Sonneborn Sons, Inc.), U. S. Patent2,575,599 (Nov. 20,1951). (77) Simon, Eli, and Thomas, F. W. (to Lockheed Aircraft Corp.), Ibid., 2,575,687 (Nov. 20, 1951). (78) Smith-Johannsen, Robert (to General Electric Co.), Ibid., 2,575,141 (Nov. 13, 1951). (79) Spatz, F. J., private communication. (80) Speier, J. L., Jr. (to DowACorning Co.), U. S. Patent 2,578,486 (Nov. 27. 1951). (81) Stanford, J. S., and Perry, Eli (to Monsanto Chemical Co.), Ibid., 2,516,351 (July 25, 1950). (82) Stark, R. E., and Dilks, B. H., Jr., Materials & Methods, 35, NO. 1, 98-9 (1952). (83) Stedman, R. F., Chem. Eng. News, 29,5030 (1951). (84) Sussenbach, Paul (to Presstite Engineering - Co.), . . U. S. Patent 2,546,059 (March 27, 1951). (85) Sweeney, D. R., Arnold, L. K., and Long, J. T., IND.ENQ. CHEM.,44, 1582-6 (1952). (86) Thomas, Beaumont (to Delrac Corp.), U. S. Patent 2,571,994 (Oct. 23. 1951). ---(87) Tice, E. A., Plating, 38, 826-30 (1951). (88) Tirpak, E. G., Civil Eng., 21, No. 8, 33-6 (1951). (89) Tolley, G., J . Applied Chem., 1, 86-90 (1951). (90) Walton, R. K. (to Union Carbide & Carbon Corp.), U. S. Patent 2,585,196 (Feb. 12, 1952). (91) Watson, W. R., Jr., and Swiss, Jack (to Westinghouse Electric Corp.), Ibid., 2,562,004 (July 24, 1951). (92) Wehmer, F. J., and McCallan, J. M., Jr. (to Minnesota Mining & Manufacturing Co.), Ibid.,2,588,442 (March 11, 1952). (93) Werking, L. C., Chem. Eng., 58, No. 1, 218 (1951). (94) Wiederholt, W., Werkstofe u. Korrosion, 2, 372-7 (1951). RECEIVED for review July 18, 1952. ACCEPTEDJuly 18, 195a , - - - - - - I
