CEMENTS C. R. PAYNE,
Electro Chemical Engineering & M f g . Co.,
750 Broad S t . , Emmaus, Pa.
An extrusion process has been perfected for the production of pipe from furan resin cements. Foamed-in-place resin cements based on phenolics, isocyanates, and silicones are finding many important applications in the Navy and the aircraft industry. Polyester cements are being used to advantage in the fabrication of truck transport tanks for chemicals and food products. Metal-to-metal bonding with epoxy resin cements is widely practiced in the aircraft industry. A breathing-type mastic has been developed for the protection of rigid insulation.
event the hull is damaged. The cement has a density of 1 to 3 pounds per cubic foot and is transformed from a liquid resin cement to a strong cellular solid in 3 minutes. It is much cheaper than balsa wood which was previously used. The Navy is also exploring the possibility of using phenolic foam as thermal insulation and sound absorption materials on aircraft carrier?. In the aircraft industry foamed-in-place phenolics are finding their place as structural stiffeners for wing assemblies and absorbers of resonant vibration. Phenolic foam is classified a': self-extinguishing, because i t will not burn when the source of flame is removed. Phenolic foams compete with the isocyanate foamed-in-place resins that have proved excellent for the protection of aircraft and ship radar antenna (93). These isocyanate based foams are formed by the conversion of an alkyd resin to a higher polymer and simultaneous evolution of carbon dioxide. Properties of isocyanate foam are:
T""?
ctory and service record of 100 carbon brick linings in alkaline pulp digesters has been described (49). Linings 2.5 inches thick have not been as successful as 4.5-inch linings. Experience has taught what limits must be maintained on lining thicknesses and on control of materials. With proper design and materials of construction, service life periods of 12 to 15 years have been obt,ained. The carbon brick linings in most of these digesters have been joined with portland cement. FURAN RESIN CEMEKTS
One of the most interesting developments this year is the extrusion of pipe from furan resin cement, (19). Furan extruded pipe has: Compressive strength Flexural strength Tensile strength Bursting etrength, 2-inch pipe Specific v a v i t y CoefficiGt of expansion/ 0 C.
Density, lb./cu. ft. Tensile strength, lb./sq. inch Compressive strength Moist,ure absorption, 7' Thermal Conductivity, B.t.u./sq ft./inch/hr./' F.
Lb./Sq. Inch 14,100 8,900
4,300 650 2.16
1.61 10-6
x
Advantages of this new- extrusion process are lower cost and the use of novel compositions that did not lend themselves to the production of furan pipe by processes formerly uaed. Extruded furan pipe is made with high or low thermal or electrical conductivity and can be threaded. Flanged fittings may be used without decreasing the strength of the pipe. Furan extruded pipe is satisfactory for temperatures to 275" F. and has the same wide resistance to corrosive chcrnicals as furan resin cements (37, 38). In general, furan pipe is resistant to all alkalies, nonoxidizing acids, and practically all organic solvents. A patent has been granted on a furan cement made from furfurylacrolein, furfural, and formaldehyde (26). The feature of this cement is that, unlike other furan cements, i t sets at room temperature if an alkaline catalyst is used. Thus, i t bonds to concrete or other alkaline surfaces without the aid of a primer and also has good adhesion to wet surfaces. A furan resin cement with a low shrinkage is produced by using benzenesulfonyl chloride and trichloroacetic arid as a catalyst (18). Furan resin cement played an important part in the new SmithDouglas wet process phosphoric acid plant a t Streator, Ill. (8). An eight-compartment leach system is used consisting of two 17-foot-diameter tanks. Each tank is divided into four compartments by vertical baffle walls made of acidproof brick bonded with furan resin cement. The steel tank is also protected with a brick lining bonded with furan cement. PHENOL-FORMALDEHYDE RESIN CEMENTS
Phenolic foam, made by adding a foaming agent to a phenolformaldehyde cement that sets a t room temperature, is used to fill voids along the water line of aircraft carriers (11). These voids, usually between the inner and outer steel shells of the ship, must, be filled to impart buoyancy and to prevent listing in the
10 235 275 2 0.3
Another type resin foam is made from polystyrene, but unlike the phenolic foam, it must be heated to foam; this somewhat restricts its industrial uses (31). Polystyrene beads impregnated with the foaming agent are subjected t o 110" C. in molds. Heat resistant silicone foam is formed similarly ( 3 2 ) . The heat distortion temperature of silicone foam is between 700' and 800" F . I t s excellent heat resistance and low thermal conductivity suggest a broad potential in thermal insulation. At present, however, principal interest in silicone foam centers on its use as a foamed-in-place sandwich core for aircraft and guided missiles. The modification of various intermediate phenol-formaldehyde condensation products by means oi 1,2 epoxides has been described (23). A new water-soluble plasticized phenolic resin is just getting into large male production (6). This new resin has three components: a phenol-formaldehyde resin, an alkyd resin, and ammonia that reacts with the alkyd constituent to make the product completely water-soluble. Phenol-furfural resin cements have been used to form a bond between the mrt'al and glass of an electric lamp and its base. This application is limited because of adhesion loss at higher temperatures. B y adding a silicone resin in a solvent t o this cement, lamp temperatures may be considerably higher without adhesion loss ( g 2 ) . POLYESTER RESIN CEMENTS
The use of polyester resin cement t o fabricate a new plastic truck transport tank for chemicals promises lower initial cost, reduced maintenance, and increased pay loads ( 5 ) . The oval shaped tank has a 3400-gallon capacit'y and weighs only 7025 pounds as compared with a weight of 11,600 pounds for a tank made of steel. The tank is fabricated by applying the polyest'er cement over a wood mold. A mat of fibrous glass is then placed in position followed by more cement. A special catalyst cures the resin. The first tank truck is being used to transport formaldehyde. Under consideration are additional units for transporting liquid alum, alcohols, acetic acid, and many other cor-
2053
2054
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 46, No. 10
End of Oil Fire Test on Loaded Steel Beams Blastic coated beam remained intact; uncoated beam failed
rosive chemicals. A milk truck tank wit,h a capacity of 4000 gallons has been fabricated in a similar manner, but the "sandwich" const,ruction of the t'ank walls includes a 2-inch-thick core of balsa Lvood for added insulation, This tank has a thin stainless steel lining inside t o meet sanitary requirements governing the transportation of milk (29). Similarly lightweight chemical resistant crocks and containers of various sizes are now being produced commercially ( 2 7 ) . Glass mat, dranm from rolls, is impregnated Tvith polyester resin cement and cured in a cont'inuous process t o form long lengt,hs of translucent struct,ural paneling (30). Versatile ccinents have been prepared from diisocyanates and low molecular weight polyhydroxy compounds in a series of reactions related t o those t'hat yield the recently announced abrasion resistant polyester rubbers (9). The use of polyester cements for joining acidproof brick t,ank linings and for floors was described in the previous annual review ($9). EPOXY CEMENTS
The epoxy resin cement's are nom expanding far beyond their original uses in t,he field of corrosion-proof const,ruction (15). X o t only have t,hey shown excellent promise in the fabrication of glaes laminates, but they are of considerable value in the preparation of very lightu-eight, strong, heat resistant foams with a weight of 2 pounds per cubic foot, developed chiefly for the h m e d Services. Metal-to-metal bonding Jyith epoxy cements is widely prac.t,iced nom in the aircraft industry and can be expected t o be adopt,ed by the automotive, shipbuilding, and other industries (2, 20, 3.4). Rubber-t'o-met'al and rubber-to-plastic joints are feasible with epoxy cements. The rubber must be cyclized before bonding with epoxy cement's. Block shear bond strengths of epoxy cement joints between metals range fiom 5000 t o 6000 pounds per square inch. Mixtures of polyamide and epoxy resins yield durable cements and casting and potting compounds (40). The polyamide resin is said t o react with epoxy resin t o give a more flexible cross link than ethylenediamine which is normally wed. The extremely high bond strength that r e d t s from the impregnation of fibrous glass with epoxy cements has made possible
the development of a,n air storage tank for jet aircraft starting systems that is 35y0 lighter than a comparable steel tank (28). Cements varying from elastomers t o hard resins can be prepared by simple mechanical mixing a t room temperature of Thiokol liquid polymers and liquid epoxy resins ( I d ) . These cements are of interest to nianufacturers in t,he potting, adhesive, and coating fieldl.. BITUMINOUS CEMEKTS
As reported in the preview review, cold applied asphait mastics modified Tvit>hsynthetic resins and rubber are used in large volume for the protection of the outside of chemical equipment, part'icularly equipment exposed t o weather and/or corrosive chemicals. This Same type cement r h e n mixed r i t h lightweight insulating materials, such as cork, produces a westherproof insulation. h new development in t,his type product is a "brcathing" mastic designed for use over rigid typee of insulat,iori, permitting the passage of ent,rained moisture through t,he mastic cement ( 1 6 ) . This product will permit the drying of insulation containing as much as 75% added water by xeight and hea,ted with steam a t 150 pounds pressure a.ithout damage to the mastic. Development n-orlr has been done on a fire retardant mastic for the insulation and prot'ection of steel to prevent its collapsc in an industrial fire. I n a large scale test two 6-inch etee! I beam5 15 feet long were loaded and suspended a fex inches above an oil fire. One steel beam was uncoated: the other was protected with 3ilc-inch fire retardant mastic. T i t h i n 7 minutes t,lie uncoated beam vias heated to a temperatmureabove 1000" F., and it failed. At the end of 23 minutes the coated beam v a s a t a teinperature of 760" F. and shon-ed no signs of failing. IIowevcr, this experimental mastic added ,some fuel t o the fire during the first part of the test, and this is objectionable. Subsequent experiment? indicate that this dificulty can be eliminated ( 1 7 ) . HYDRAULIC CEMENTS
The use of precast insulated concrete wall panels has c u t the cost' of wall construction as much as 33% and reduced erection time half (4). These precast panels range in thickness froin 5 t o
October 1954
INDUSTRIAL AND ENGINEERING CHEMISTRY
8 inches with a choice of area dimensions suchas 8 X 8 ft. or 8 X 10 ft. Panel edges have tongue and groove contours. Sealing between panels is done by using rubber strips and calking compound. Cast-in metal inserts bolt directly t o the steel building framework. By using a sandwich of insulation in the panel a favorable heat transmission factor is obtained. A summary report has been issued on portland cement concretes t h a t have been developed with the use of various aggregates to impart specific nuclear properties t o the concrete for shielding purposes (21). I n another study, cements of different composition were exposed t o thermal neutrons and gamma rays in view of studying their shielding properties. -2 cement with tourmaline and serpentine is one of the best (1). A modified hydraulic cement, which is particularly adapted for cementing oil and gas wells, is obtained by mixing a cement with an oxidized paraffin. At 00" F., the stiffening time or the limit of pumpability of the portland cement slurry was increased from 70 to more than 400 minutes (3.5).
2055
gedness and freedom from distortion during the test a '/2-inchthick asphalt mastic was adopted for this application. Equipment lined with acidproof brick bonded with furan resin cement is used for the production of peacock blue, the most extensively used blue ink pigment in the mult,icolor printing industry (25). The acid sulfonation product is charged into a brick lined vessel that had previously been filled with water and ice. Soda ash is then poured into the vessel a t a rate determined by foaming. Ice or steam is then put into the batch t o obtain the desired temperature. This application illustrates the versatility and durability of furan cement joined brick linings. ACKKOWLEDGMENT
The assistance of W. H. Rutter and R. R. Graver, Electro Chemical Engineering & Mfg. Co., in the preparation of this review, is greatfully acknowledged. LITERATURE CITED
MISCELLANEOUS CEMENTS
Pressure-tight seals in threaded pipe joints can be afisembled with much less force than is ordinarily required by using a cement made of Teflon. The low coefficient of friction of Teflon permits easy assembly of pipe joints and makes a tight seal. The joint has a high resistance t o heat and is chemically inert (44). A cement made of sodium silicate and asbestos fiber has proved satisfactory for lining a vacuum flasher column to combat corrosion due to sulfur-containing vapors a t high temperatures (42). A new silicone cement has been developed t h a t has good adhesion to metals, glass, and plastics including polyethylene or polyester films. Reported advantage is that this cement will adhere to most surfaces when applied under water (19). A new room temperature curing silicone cement is supplied as two separate components. When mixed these react to form a cement that sets in 4 hours and is useful as a calking and glazing cement or as a n encapsulating or casting compound (24). IMPERVIOUS MEMBR4NES
Pioneering work in 1953 w e d atomic energy developments to produce useful changes in the physical properties of long chain polymers. Polyethylene irradiated in a n atomic pile for a short period becomes cross-linked and withstands temperatures up to 250" C., whereas the melting point of the ordinary polymer is approximately 115 C. Nylon, polystyrene, polyvinyl alcohol, and polyvinyl chloride have all been cross-linked by pile irradiation. Polytetrafluoroethylene decomposes by chain scipsion under similar treatment (3,24, 4.5). Fluorochemicals are now produced b y a n electrochemical process involving a mixture of the organic base and anhydrous hydrogen fluoride in an electrolytic cell. These monomeric materials promise to be of value for the development of improved synthetic rubbers and heat resistant plastics (56). A recent development of a welding method for Kel-F film makes it usable for lining tanks to safeguard against corrosive attack. Since the welding procedure is only successful in bonding the film to itself, the lining must be supported inside the tank by an acidproof brick lining (7). Cooperative research by the Army's Ofice of Quartermaster General and bI. W. Kellogg has resulted in the development of a Kel-F chlorotrifluoroethylene fluorocarbon elastomer reputed to have properties not found in other rubber products. Unique features of this rubber are its resistance to fuming nitric and sulfuric acids and its imperviousness to hydrocarbon fuels. It is believed that this new rubber can be applied as a tank lining (10). INDUSTRIAL APPLICATIONS
Field tests of exterior protection for pipelines conveying fuel oil heated to 200" F. have been completed (41). Due t o its rug-
(1) Bourgeois, A., and Jacquesson, J., J . phys. r a d i u m , 14, 317-22 (1953). (2) Carey, J. E., ModernPZastics, 30, 130-2 (August 1953). (3) Charlesby, A, Plastics ( L o n d o n ) , 18, 142-5 (May 1953). (4) Chem. Eng., 60, No. 9, 244-5 (1953). (5) Ibid., No. 10, p. 246. (6) Ibid., No. 11, p. 116. (7) Ibid., 61, No. 2, 276 (1954). (8) Ibid., No. 6, pp. 128-30. (9) Chem. Eng. N e w s , 31, 3985 (1953). (10) Ibid., 32, 1158 (1954). (11) Ibid., pp. 1472-4. (12) Chem. Processing, 16, No. 10, 43 (1953). (13) I b i d . , 17, No. 2, 20 (1954). (14) Ibid., No. 5, p. 36. (15) De Bell, John M., M o d e r n Plastics, 31, No. 5, 87-9 (1954). (16) Earl Paint Corp., Utica, N. Y., Bull. 15 (1954). (17) Ihid., Bull. 100 (1954). (18) Edmunds, Alvin &I,, and Sonnabend, L. F. (to Dow Chemical Co.), U. S. Patent 2,655,491 (October 1953). (19) Electro Chemical Eng. & Mfg. Co., 750 Broad St., Emmaus, Pa., Bull CN-22 (1954). (20) Epstein, G., M o d e r n Plastics, 31, No. 5,93,95-6 (1953). (21) Gallaher, R. B., and Kitzes, A. S., U. 9. Atomic Energy Comm., Tech. Inform. Service, Oak Ridge, Tenn., ORNL-1414 (1953). (22) Hardwick, Robert F. (to General Electric Co.), U. S. Patent 2,633,457 (March 31, 1953). (23) Harris, Thomas G., Homing, Roderick H., and Neville, Harvey A,, M o d e r n Plastics, 31, No. 4, 136-40 (1953). (24) IND.ENG.CHEW,45, 11A, 1 3 8 (September 1953). (25) Ibid., 45, 1610-18 (1953). (28) Lantz, Wm. J., and Walters, Joseph M.(to Electro Chemical Eng. & Mfg. Co.), U. S. Patent 2,660,573 (Nov. 24, 1953). (27) M o d e r n Plastics, 31, No. 4, 110 (1953). (28) Ibid., p. 181. (29) I b i d . , N o . 6, p. 87 (1954). (30) I b i d . , p. 89. (31) Ihid., No. 9, p. 103. (32) Ibid., p. 133. (33) Monsanto Chemical Co., 1700 S. 2nd St., St. Louis 4, Miss, Bull. P-144 (1953). (34) Narracott, E. S., Brit. Plastics, 26, 120-3 (Ami1 1953). (35) N. V. de Bataafsche Petroleum Maatschappij, Dutch Patent 721,139 (April 15, 1953). (36) O'Keefe, P., Materials & Methods, 37, 110-14 (April 1953). IND. ENC.CHEW,42, 2030-1 (1950). (37) Payne, c. R., (38) Ihid., 43, 2286-7 (1951). (39) Ibid., 45, 2185-8 (1953). (40) Plastics W o r l d , 11, No. 8, 15 (1953). (41) Slauffacher, E. R., and Davidson, R. R., Corrosion, 9, KO.10, 377-81 (1953). (42) Stormont, D. H., Oil Gas J., 51, No. 46, 255-7 (1953). (43) Thomas, Beaumont, presented at 39th Annual Xeeting of TAPPI, Feb. 16, 1954. (44) Thompson, J. B., and Nielsen, G. C., Chem. E n g . , 60, No. 11, 196 (1953). (45) Wall, L. A,, and hfagat, RI., M o d e r n Plasfics, 30, 111-12 (July 1953).
