CEMENTS C. R. PAYNE,
Electro Chemical Engineering 6% Manufacturing Co., 750 Broad St., Emmaus, Pa.
N e w furan condensation products have high strength and low shrinkage and are suitable materials for casting pumps, distributor trays, and similar corrosion-proof equipment. Wood impregnated with furan cement has proved to be economical for filter press plates and frames, Polyester cements are finding increased applications in the chemical equipment field; they are used to join the brick linings of equipment handling chlorine dioxide solutions in bleaching paper pulp. When the polyester cement is reinforced with glass fiber i t is used to fabricate tanks, fume ducts, hoods, and pipe. Epoxy cements are used as chemical-proof coverings over concrete floorswhere trucking is not severe.
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Y FAR the greatest tonnage of acidproof cements continues to be used as a mortar for acidproof masonry, such 8s brick-lined tanks, reactors, towers, stacks, fume ducts, floors, manholes, and sewers. With improvements in the physical properties of resin cements, large quantities are being used in a variety of new applications. FURAN RESIN CEMENTS
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A new series of storage-stable liquid furfural-ketone condensation products has been placed on the market in commercial quantities (18). These liquid resins, when mixed with carbon flour and an acid catalyst, set t o a n infusible cement a t room temperature. The resulting cement is stronger than furfuryl alcohol cement and is said to have lower shrinkage. Distributor trays, pumps, and similar cast parts now under test show considerable promise. Because of the ease with which the material may be handled, it is probable that in the future many chemical plants will cast corrosion-proof equipment of this type in their own shops. When properly reinforced with glass fiber, these cements can be used to produce flat sheets and reinforcing angles in the same manner as furfuryl alcohol resin cements (44). Thus, troughs, fume ducts, fume hoods, hoppers, and small tanks can be fabricated in the field, and the use of cements for this type of corrosion-proof equipment has been growing rapidly. Rigid polyvinyl chloride sheets, glass fiber reinforced polyester, and furan resin sheets are the major materials used for this purpose ( 7 , 10, 67). Each resin has its own application and is not necessarily competitive t o the other. The choice of material for a particular application depends on a careful study of the chemital resistance and physical properties of each material (3, 7, 31, 34, 36,37,42, 43,67-60). In general, the furan resins withstand temperatures up to 360" F. and are inert to alkalies, most solvents, and all acids except the highly oxidizing ones. The polyesters withstand temperatures to 350' F. and are inert to most acids, including cold dilute solutions of nitric and chromic acid, but are not satisfactory for handling alkalies and some solvents such as ketones, aniline, and carbon disulfide. Rigid polyvinyl chloride witJhstands temperatures up t o 160" F., is inert to all acids including nitric up to 40% and chromic up to 50%. It is inert to alkalies but is attacked by most organic solvents. I t s strength rapidly decreases with increasing temperature, whereas polyester and furan sheets maintain good structural strength a t high temperatures. The impact resistance of the glass fiber reinforced polyester or furan sheet is much greater than that of the rigid polyvinyl chloride sheet. Consideration of these properties in relation t o the chemicals being handled and the maximum temperature of the operation along with other operational factors such as mechanical impact, temperature shock, and structural strength
required will ensure the correct choice of materials of construction. As reported in the previous annual review, improvements have been made in the composition of furan cements used for the impregnation of wood and also in the technique of impregnation. After 2 years of service in chemical plants, furan impregnated wood filter press plates and frames have proved their economy over untreated wood in acid service (44). After 2 years of service in hot acid, the furan impregnated wood had over three times the strength and hardness and less than one third the swelling and absorption of untreated wood. Furfural-aniline cements have a strong affinity for bituminous products. For example, cinders lightly coated with this cement, prior to adding the bituminous material, will outlast the usual cinder roads (19). This product is also a n excellent waterproofing material ( 5 6 ) . A furfuryl alcohol-ammonium thiocyanate-aldehyde resin cement suitable for impregnation and laminating purposes has been developed (20). Furfuryl alcohol cement is used as a n inert impregnant for stoneware and sandstone and as a base for a conductive floor in hospital operating rooms and explosive plants to reduce the possibility of electrostatic discharges (36). Furfuryl alcohol is also being used in forming cements from urea-formaldehyde resins for gluing plgp-ood ( 6 7 ) . Low temperature acid catalyzed furfuryl alcohol cements are being used in the aircraft industry (67). A new method of determining the volume shrinkage of furan cements has been studied (55). POLYESTER RESIN CEMENTS
For over 6 years, polyester cements reinforced with glass fiber have been used successfully for the construction of plating tanks, pipe, fume ducts, and similar corrosion-proof equipment ( 4 4 ) . More recently, a tank measuring 8 feet high and 14.5 feet in diameter has been built and handles ammonium sulfate liquor a t the Mobile, Ala., plant of the American Cyanamid Co. This tank handles 4000 gallons of liquor at temperatures up to 240' F. Side-wall thickness is 3/8 of an inch and bottom thickness */z inch ( 7 ) . Tanks of 1000-gallon capacity are used for transporting fuel and water across the Arabian Desert. It is claimed that they will last 10 to 50 times as long as steel tanks, since one sandstorm can rip the paint from steel. The Navy has contracted for a number of compressed gas cylinders of 50-pound capacity. They must be nonmagnetic and must withstand 2000 pounds per square inch pressure ( 7 ) . Until recently, polyester cements were not used in large quantities for joining acidproof brick tank linings and floors. Polyester cements have greater resistance to chlorine dioxide than other types of thermosetting cement. Therefore, with the development of a new process for the manufacture of chlorine dioxide and its use for bleaching pulp, polyester cements are being used in larger quantities to join brick linings in chlorine dioxide towers, bleaching towers, storage tanks, and similar equipment in paper mills (11). Up to the present time, polyvinyl chloride sheet linings have proved to be the safest practical impervious membrane to use between the steel shell and the brick lining which is joined with polyester cement.
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INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
Vol. 45, No. 10
250" 3'. were prepared by heating mixtures of aconitic acid, a polyepoxy compound, and an acid containing three to six carboxylic acid groups ( $ 7 ) . Epoxy cements are used as linings for tank ortrs transporting chemical^, as potting compounds for subminiature electronic units, television components and frequency filters for coaxial telephone cables, materials for aircraft sandwich construction, encapsulation of electrical components requiring a tough, protective cement of high dielectric strength, and as a sealant for storage batteries (39, 47, .50,61). PHENOL-FOHMALDEHYDE RESIN CEMEWTS
A new cold-eetting, alkali-resistant phenol-formaldehyde cement, which is satisfactory for chemical construction, has h e n produced by mixing a phenol-formaldehyde resin with aliphatic esters of furfuryl alcohol, p-toluene sulfonic acid, and an inert filler ( 2 3 ) . Further investigation has been made of phenolformaldehyde cements t h a t cure at low temperatures. Thc setting process of phenol-formaldehyde cemenkq with regard to temperature increase and pH required to catalyze the setting reaction %-asstudied (4, 46). A new phenol-formaldehyde resin cement that possesses fast cure and high temperature rigidity has been developed ( 5 ) . This product resulted from the study of the gel time of the six isomeric biphenols which are rated from slow t o fast as follows: 2,4'-; 4,4'-; 2,3'-; 3,4'-; 3,3'-; aiitl 2.2 '-diphenvlolmethnne,
Figure 1. Distributor Tray Cast from Furan Resin Cement for I T s ei n a Chlorine Scrubber
I n floor construction, polycster cements are being used as a trowel coat over concrete and as a joining material for tile (8). Although their chemical resistance is not as universal as the furan or phenol-formaldehyde cements, the poll esterq do bond to concrete well ( 3 , 6 , 7 , 28, 32, 34, 35, 37, 68). .kc a result, the polyesters are excellent for bonding tile t o concrete walls and for pointing portland cement joints. In general, the polyester cements withstand temperatures up to 350" F., are inert t o most acids, but arenot satisfactoryfor handlingalkalies or solvents such as ketones, aniline, and carbon disulfide. Highly filled polyester cements have found use as a calking compound (58). Diluted polyester eements are used to impregnate castings and porous fiberboard. They have also been used as a coating on radiation shields to protect workmen from radiation (49). Polyester cements were used to bond dried quartz particles to produce a new high frequency insulating material (52). EPOXY CEMENTS
Resin cements based on epoxy resins, though available only since 1950, are coming into widespread use in the field of corrosion-proof construction (10). Epoxy resin cements bond t o concrete with an adhesion of over 400 pounds per square inch. For this reason they are proving successful as a corrosion-proof trowel coating over concrete floors and piers where abrasion is not severe. Cinder block walls are made corrosion-proof, smooth, and attractive with a trowel coat of epoxy resin cement. Increased resistance t o mechanical impact is obtained by reinforcing the resin cement with glass fiber. Epoxy cements withstand most acids except the highly oxidizing ones and are inert to alkalies. They are attacked by such solvents as ket,ones, aniline, and esters ( I g , 13, 54, 62, 63). By the styrenation of the fatty acid esters of the epoxy resins, the resistance of these resins to water and alkali has been increased without hindering the excellent adhesion and flexibility characteristics ($0). Epoxy resins t h a t were not deformed at
Figure 2. Condenser Water Boxes €or lG5,OOO K.V.A. Generator Lined with Keoprene Cement for Handling Corrosive River Water
Phenol-formadehyde resin ccniente are used in bonding abrasive grains together in forming grinding wheels of exceptional strength (38). The use of chromium compounds, such as sodium dichromate, with phenol-formaldehyde cements greatlyaccelcrates the setting rate of the cement when used for plywood adhesion (14). The use of phenol-formaldehyde cements for impregnating compressed wood has been studied with reference to shear and impact strength and the effect of changes in time, temperature, and pressure during the curing cycle ( 1 7 ) . These cenients are also being used in the foundry industry a s a cement for core bonding. I t was reported that these cores were suitable for casting aluminum, bronze, gray iron, malleable iron, and stccl (48, 63). Modified phenolic cements are also iinding use as a glass adhesive (41). -4neoprene-phenolic cement for bonding abrasive,
October 1953
INDUSTRIAL AND ENGINEERING CHEMISTRY
coated sheets to metal, rubber to glass, and plastic laminates t o wood has been described (66). Phenol-formaldehyde resin using epoxy resins a a curing agent are used for bonding metals (68). The adhesion of phenol-formaldehyde cements to metal has been investigated in considerable detail. Included in the study was the relation between tensile strength and such factors a8 the method of cleaning the metal surface, the degree of condensation of the resin, the alkali content of the resin, age of the resin cement, the preliminary and final hardening time, and the thickness of the cement layer (21).
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mens have much higher tensile strength than soak-jointed swniples. A bituminous composition suitable for use as a pipe-jointing compound consists of rubber, accelerator, asphalt, clay, and sulfur (16). The product has R softening point of 212’ F. and is suitable for airfields and road construction where climatic conditions necessitate a high resistance to flow under heat.
SULFUR CEMENT
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The tentative specifications for sulfur cements have been approved by the sponsoring committee and accepted by the American Society for Testing Materials for use pending adoption as a standard. These tentative specifications have an ASTM Designation C 28762T and are published in 1952 in Part 3 of the ASTM Standards. The specificat,ions list minimum requirements of physical and chemical properties, along with methods of testing. A liquid orgrtnic polysulfide that is converted to, rubber a t room temperature has been developed (66). It is being used for sealing integral fuel tanks in aircraft, for calking ship decks, and for casting gaakeQs in place on various types of machinery. A mixture of organic polysulfide and an epoxy resin is suitable for use as a pipe-jointing compound. HYDRAULIC CEMENTS
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A detailed study revealed that when a polyvinyl acetate emulsion is mixed with portland cement, in a polymer to cement ratio of 0.2, and cured a t an average relative humidity of 35%, the strength obtained after 28 days was equal to 10 times that of normal cement mortars cured under similar conditions. Other advantages w e better workability, bond strength, and resistance to impact, abrasion, and corrosion ($2). This cement has been found useful aa a tapping for floors and roads. It was reported that the addition of calcium chloride to portland cement produces a product which can be utilized to advantage in oil well drilling where the problem is to join a split in a casing (16). A cement product with occlusion of air mist and with a superior tensile strength can be obtained by the addition of a sodium hydroxide solution of amyl abietate to the portland cement mixture (1). The resistance of concrete to freezing and thawing has been greatly increased by the addition of a soluble oil which entrains 3 to 6% air to the concrete mixture. The soluble oil also decreases the water requirement of the mixture (%). Diatomaceous ewth, when added to cements used in oil well cementing, gives a more exacting control of slurry weights, yield, bleeding, uniformity, and setting (31,64). A cement composed of granulated slag, portland cement, sand, and gypsum is being used for forming a corrosion-resistant lining in metal pipe (46). A cement mixture possessing good workability, high strength, and minimum shrinkage was prepared by blending an hydraulic cement with diatomaceous earth and an amine salt of a polyhydroxycarboxylic acid. The acid used must have a t least 4 and not more than 18 carbon atoms in the chain (26). MISCELLANEOUS CEMENTS
Excellent rubber to metal adhesives, with good adhesion a t high temperatures and good resistance t o shock, are obtained from the reaction of alkyl phosphates with isoprene, butadiene, or chloroprene (244). A study has been made evaluating the role of carbon black in adhesive cements used to bond rubber to metal (61). A method for “dough jointing’’ acrylic resins based on in situ polymerization has been described (40). The dough consisted of methyl methacrylate polymer dissolved in the monomer and an oxygen-producing catalyst. Dough-jointed speci-
COURTESY OF LAMINEX CORP.
Figure 3.
Venturi Produced from Polyester Cement Reinforced with Glass Fiber
An oxychloride cement is finding use as a shock-resistant lining for freight cars. It is said that the material can be applied as smooth as plaster and is as nailable and shock-resistant as wood (9). IMPERVIOUS MEMBRANES
While properties are important guides, practical experience is often more helpful in choosing the proper impervious membrane to use behind acidproof brick linings. Practical experience in chemical plants with hard rubber, polyvinyl chloride, Buna-NBuna-S copolymer, polyvinylidene chloride, polyethylene, tetrafluoroethylene, chlorosulfonated polythene, neoprene, and natural rubber has been reported (7). Chlorosulfonated polythencl is so new that little industrial experience with i t has been reported as yet, but it has unique properties. Indications are that it can be compounded to withstand the attack of fuming nitric acid, 95% sulfuric acid, concentrated chromic acid, and glacial acetic acid. Other elastomers are disintegrated or severely attacked by these chemicals. The resin does not require carbon black for reinforcement or weather resistance, hence light colors are possible in the lining material. I n 1940 the Navy undertook an extensive construction program of underground prestressed concrete tanks for storing aviation gasoline. The tanks were lined with organic polysulfide polymers. The linings have proved satisfactory, but were subject t o attack by molds and bacteria under conditions of tropical temperature and humidity. This attack can be inhibited by treating the polysulfide linings with pentachlorophenol ( 2 ) . A number of improved polysulfide polymer compositions for tank linings have been developed (33). A new aqueous colloidal dispersion of polytetrafluoroethylene can be applied in a single application to give a film thickness of 1.5 mils (29). These coatings can be bonded to metals by baking a t 750” F. Because of their “antistick” properties and corrosion, resistance they are widely used in chemical equipment.
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INDUSTRIAL AND ENGINEERING CHEMISTRY ACKNOWLEDGMENT
The assistance of W. H. Rutter, Electro Chemical Engineering &: Mfg. Co., inthepreparation of thisreview is gratefully acknowledged. LITER.4TUHE CITED
(1) Aima, Ryuzo (to Nippon Rosin Co.), Japan. Patent 3681 (July 13, 1951). Allen, F. H., and Fore, Dan, Jr., IXD.ENG.CHEM.,45, 374-7 (1953). American Cyanamid Co., 30 Rockefeller Plaza, New York 20, N. Y . ,Bull. 4128 (June 17, 1952). Bedwell, M. E., Selected Gout. Research Repts. (Gt. B r i t . ) , 1 (1952), NO. 8, pp. 221-38. Bender, H. L., Modern Plastics, 30, 136-8 (February 1953). B i i t . Plastics, 24, 415-20 (December 1951). Bruner, W. M., and Wayne, P. J., Chem. Eng., 60, No. 7, 193204 (1953). Ceilcoat Co., 4832 Ridge Road, Cleveland 9, Ohio, Bull. 110 (1952). Chem. Eng., 59, No. 9, 196 (1952). Ibid., 59, No. 12, 143-90 (1952). Ibid., 60, No. 6 , 105 (1953). Ciba Co., Inc., 631 Greenwich St., New York 14, N. Y., Bull. 9853 (1950). Ibid., CN501 (1951). Cone, C. N. (to United States Plywood Corp.), U. S. Patent 2,612,481 (Sept. 30, 1952). Council of Scientific and Industria1 Research, Indian Patent 43,320 (Feb. 2, 1952). Craft, B. C., J . Petroleum I’echnol., 4, No. 6, 11-12 (1952). Dadswell, H. E., Fitzgerald, J. S., and Tarnblyn, N., Australian J . A p p l . Sci., 3,71-87 (1952). Dunlop, A. P., and Peters, F. S . , “The Furans,” p. 780, New York, Reinhold Publishing Corp., 1953. Ibid., p. 782. Dunlop, A. P., and Stout, P. R. (to Quaker Oats Co.), U. 8. Patent 2,589,683 (March 18, 1952). Ehlers, J. F., Kunststoffe, 40, 151-7 (1950). Geist, J. hI., Amagna, S. V., and Mellor, B. B., IXD.EXG. CHEW,45, 769-67 (1953).
Himsworth, F. R., and Hughes, Harry (to Imperial Chemical Industries, Ltd.), U. S. Patent 2,592,034 (April 8, 1952). Kalafus, E. F. (to General Tire & Rubber Co.), Ibid., 2,619,445 (Nov. 25, 1952). Keating, P. J., Jr. (t,o Texas Go.), Ibid., 2,614,939 (Oct. 21, 1952).
Klein, Alexander (to Louis S. Werte), Ibid., 2,588,248 (March 4, 1952).
Koroby, J. E. (to Rohm & Haas Co.), Ibid., 2,623,023 (Dee. 23, 1952).
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Vol. 45, No. 10
(28) Laminex Corp., 994 Jefferson St., Fall River, Mass., B u l l . CRT (1952). (29) Lontz, J. F., and Happoldt, W.B., Jr., IND.ENQ.CHEJI.,44, 1800-5 (1952). (30) McNabb, J. W., and Payne, H. F., Ibid., 44, 2394-7 (1952). (31) hlanaold. G. B.. World Oil.134. No. 6. 112-14 (1952). (32) hIarc-o Chemicals, Inc., 1711 Elizabeth Ave., ‘Linden, N. J., Bull. MR-28C (1952). (33) Massa, A. P., Colon, H., and Schurig, W. F., IND.EXG.CHEX, 45, 775-81 (1953). (34) Modern Plastics, 29, 95-8 (June 1952). (35) Ibid., 29, 80-1 (July 1952). (36) Ibid., 30, 111-99 (January 1953). (37) Ibid.. 30. 96-7 (Februarv 1953). Ibid.: 30: 169 (Ami1 1953). Ibid.; 30; 111-24-(May 1953). Morrow, R. B., Australian Plastics J . , 8, 41-5 (Februarv 1952). hloser, Frank, Ceram. Age, 60, No. 4, 31-3 (1952). Payne, C. R., IND. EKG.CHEX,42, 2030-1 (1950). Ibid., 43, 228G-7 (1951). Ibtd., 44, 2292-5 (1952). Peckman, A. L. (to United States Steel Co.), U. S. Patent 2,597,370 (May 20, 1952). Pennsylvania Salt Mfg. Co., French Patent 970,944 (Jan. 10, 1961). Plastics W o r l d , 11, KO.1, 1 (1953). Ibid., KO.1, p. 9 . Ibid.. No. 3, p. 1. Ibid., KO.3, p. 40. Ibid., No. 4 , p. 21. Ibid., No. 4 , p. 29. Powers, P. O., IND.ENG.CHEM.,45, 1063-6 (1953). Preiswerk, E., and Charlton, J., Modern Plastics, 28, 85-8 (November 1950). Quaker Oats Co., Merchandise Mart, Chicago 54, Ill., Bull. 54 (May 1953). Reineck, E. A,, Modern Plastics, 29, 122-4 (June 1952). Ibid., 29, 127-32 (October 1952). Rohm & Haas Co., Washington Square, Philadelphia 5, Pa., BulE. M-7-50 (1950). Seymour, R. B., and Erioh, E. A , Chem. Eng. Progr., 48, 374 (1952). Seymour, R. B.. and Steiner, R. H., Ibid., 48, 430 (1952). Sheehan, G. M., Kraus, Gerard, and Conciatori, A. B., IND. ENG.CHEW,44, 580-2 (1952). Shell Chemical Corp., 500 Fifth Ave., New York 36, iK. Y . , Bull. SC-51-21 (1951). Ibad., SC-52-39 (1952). Sterne, W.P., Oil Gas J., 51, KO.9, 72-3 (1952). Thiokol Corp., 778 North Clinton Ave., Trenton, N. J., Bull. LP-2 (1953). Thompson, A. F. (to Minnesota Mining & M f g . Co.), U. 5. Patent 2,610,910 (Sept. 16, 1952).
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HARRY L. FISHER Unicersity of Southern California, LOS Angeles 7 , Calif
The matter of proper disposal of the government synthetic rubber plants to private industry is the most important news i n the synthetic rubber field. These plants are not war surplus but are of real use in our national security. When this is printed the disposal will probably be well along. Sixty-five per cent of the GR-S now produced is cold rubber, manufactured at 41” F. About 900,000 long tons of synthetic rubbers are being manufactured this year in this country, and 400,000 long tons of natural rubber will be imported. Oil-plasticized high viscosity synthetic rubber continues to be of importance and is now a regular article of commerce. Chemigum S L is a new synthetic rubber based partly on the German Vulcollan; it has tensile strength of over 5000 pounds per square inch without carbon black, good resistance to abrasion, and high tear strength.
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HE Office of Synthetic Rubber of the Reconstruction Finance Corp. presented t o President Eisenhower its “Program for Disposal t o Private Industry of Government-Owned Rubber-
Producing Facilities” (112). This was in accord with Congressional action and received the President’s approval. The Paley Commission chapter on rubber predicts that the world need for total rubber in 1975 will be 3,300,000 long tons, and t h a t 2,500,000 long tons of total rubber will be used in the United States, of which 50 t o 60% will be synthetic (134). The price of the synthetic G R S and Butyl rubbers may then conservatively be placed within striking distance of 20 t o 25 cents a pound in 1950 dollars, including profit margin. The commission
