__ BESRT PETERS,
Bell Telephone Laboratories, l n c . , Murray H i l l , Y. J .
T h i s biennial review of 1932 and 1933 is a s u m m a y of the work performed in the field of hard rubber. Fundamental research i3 i-elati\elyinactive. Patent interest is unusu;all> keen, and more than half the literatiwe references deal w i t h this subject. Debelopment of hard lubber from latex is gaining momentum, and claims are made that it can compete economically with methods of dry mixing,
AOSITE froni latex has hern studied hj- several inic.tig:itors. Houvr-ink ( 2 9 ) has sliowi thnt a satisfactory hnrd ruhber is obtained from a vulcanizing lates, containing GOYo 1)y weight of hydrocarbon. Latex is e a d y poured into a pl mold, dried, vulcanized, and polished. The addition of one part, of zinc dibut>.ldithiocarhaniate to a lates causes a desirable pr(Jvulcanization during drying: so as to ensure niaintennnw of shlrpe during vulcanization. Complex produrts are made in thi? way n-ithout heavy presses and molds. I n another paper by van’t \Tout (661, the technological characteridcs of lat,cr ehonite are conip:ired x-it,h those of a dry ebonite niisture. The woiioinic aspects of latex application are compared wit,h dry ebonite, taking into consideration the cost of mold., fabrication, arid wig!it per article. Capital investment for latex ebonite equipnient is ahout 80% less than the amount required for compounding a dry mix. Furtlier studies by Houwink, de I.ries, and van‘t \Tout, (30) indicate that t,he superiority of the mechanical propcrtie;: of ehonite latex products compared .ivit,h t,hose of dry r u b i ~prodwty i3 due to the molecules keeping t,heir original lenptli. Iri a very comprehensire latex-ebonite study, I,c,petit (37’1 reviews the influence of sulfur cont,ent, fillers, accelerator;;, dispersion of ingredients, drying, and vulcanization. T h c prorese opens up new possibilitie or ehonite, particularly for ahsorption molding. flow casting, d i n g , elwtroplioresis, and coi-criqg of nwt,al parts of int.ricate shape. Mechanical properties of latex ebonitc, Bakelite, and ebonite fro111 dry rubber are comp:trcd h y de Vries ( 1 6 ) . Two other papere (.TO, 5 2 ) deal ivith flexural strength, inipact resistance, and electrical properties of ebonite from latex. Uourgoie and Plantier (8) dpterniincd the physical propcLrtii.s of rlmnite without filler and with 80% filler by volume. The chemical resistance of ebonite, filled or unfilled, to solveut,s and aging is superior to that of soft ruhbcr. Luttropp (40)h:rs tleuionatrated t,hat Plastikator S o . 32, a bullr polymer of l i u t d i c n e with a molecular weight of 3’2,000 and a viscosity of iUO0 centis can be compounded irit,o a
extra, 1; and dibutylamine. According to a recent psper hy n a v i e s ( 1 3 ) , the formation of hard rubber is now regard( continuation of normal vulcanization rathcr than as a d’ process. Grouch (2s)in a veq- dcvious way has est,aijlished a n empirical minimum dielectric: loss relationship for ebonite, poiyet,hylene, and vinyl resin.. I’arbrook ( 4 7 ) hac studied the caiises for electrical breakdowi of plastic and thermoset,tirig mnterial that are exposed to gases and liquids under presaurc. The effect, is most marked above BO atniospheres pressure and with a diffusion t,ime of over 2 hours. The greatest effect w-as found with carhon dioside, ethylene, hydrogen, nitrogen, or air as the fluid; a xrnsller effect was found with water and transformer oil. Of all the materials investigated, ebonite and polyethxlene were Beast effected. Symptoms of this effert were the forniation of huhhles in the material and fissuring of the surfare. Tlic inror2112
pc>ration of Pliolite 8-0 III h u ~ d rui~l>ert o give hlgller impact stirngth 15 the suhject of a n intcxresting papei ( 2 2 ) .
CHEZIICAE .‘AT) Pi4YSIC:AL TESTING
l’ewoz ( 4 8 ) has tleveloprd methods of evaluating thermal insulation and vibration damping of cel!ular ebonite for use in xir-
BOOKS AA.33 IPEYIEWS
Several books and review articles have bren published that deal directly or indirectly with hard rubber. A n outline ( 6 % )is given of the hist,ory and present day application of chonitc, it. , and the development, of synthetic ebonites. A short als with the use of porous ebonite and the use of ebonite linings backed by soft, rubher for tank linings. The Llinistry of Supply of the Cnited Kingdom ( 3 2 ) has given an excellent resume of ewpanded ebonite and scveral types of espanded pi irere exposed to tropical conditions for a period of sis niontlis. Ebonite suffered excessive warping and permanent dist,ortion while polystyrene and polyvinyl chloridc w r c superior in thii respect. A booklet (.57), published k)>- t’lie Ilepartment of Scientitic and 1ndust)rial Itcsearch of the Unit,cd Kingdom, giws an illuminating account of t,he solvent properties of i n d a t , i n g mat,erials and the procedure adopted for a table of electrical properties is g i w n for insulating materials including ebonite and plastics. The .American Hard Rubber Co. (2, 8) has rpcently iswed n brochure tabulating the physic:il, chemical, and electrical proprrtirs ol a but,atliene-arrTloriitrile copolymer known as “Ace Ten-ipron”. To a lesrer extent, the properties of eboiiit,e and plastics are rcriened in a puh1ic:ition ( 8 0 ) by Kaeser, INDUSTRIAL PRODUCTS A X ) USKS
Cutting, machining, and buffing hard rubber have beer! irivcL.tigated €or many y e w s . Only rcccnt,ly, a machine (2.4)that was originally developed for ciitting steel has becn succedull>. uscti in Switzerland for ehonite. h disk slicer ( by t,he industry, and parallel hard rubher strips arc. obtained withoiit grinding or bufing. The effect of chemicals on hard rubber cont,inues to lje a Y U ~ J ject of much interest’. The use of chonitc ( 1 1 ) for handiing clheniicak is described as a lining rathcr than as a structural matwi:ii, with brief details of cht.mic:il and wear resistance, appliration, Find temperature. Substit’nting synthetic ehonitc (26) for soft rubher in the heavy chemiral industry has met, wit,h a fair tlc~grc’r of success. Hard rubber linings ( . ; I ) are reported as unusuwliy good for resisting liquid chlorine nnd hleaching agents. The use of expanded ehonitc ( 1 9 ) as a flotat,ion medium in lilc buoys, life boats, and rafts is the topic of one investigation. 11 means of thermally insulating a stratosphere chamber (59) witti expanded ebonite hac heen quite siiccrssful. I n another article ( 6 3 ) ebonite is comparcd lyit’h other plwties from the st,:tndpoint
October 1954
INDUSTRIAL AND ENGINEERING CHEMISTRY
of molding. With t,he application of dielectJ,ic heating aiid presEUre (66),ebonite cements have been developed to bond hard rubber t o itself. Revultex (C), a casting ebonit'e latex, is cur) spraying rently used t o mold toys inexpensively. The field ( I ? Of ebonite and plastics on inert surfaces is heing pursued. with yesteryears, has heen The patent situation, as most prolific. Altogether 54 patents have been issued during the period, nine ( 1 , 6, 16, 18, RO, 27, SS,48,5 6 ) of which were granted for the use of hard rubber in batteries. Patents ( I , l E , 18, 20, 37, 33) have been issued that deal primarily Tyith the use of ebonite in containers, covers, and trough construction. Thomas (66) has patented the use of an asphaltic sealing cornpound for bonding ebonite and plast'ics. Claims are made for a patent,able method (4g)of preparing a microporous hard rubber battery separation of greater porosity than is possible by the standard method of using latex. hh-oporous retainers ( 6 ) made from Polyblend or butadiene-acrylonitrile copolymer are better than ebonite retainers. Two interesting patents (26, 31) were granted for detecting cracks in hard rubber. The first patent describes the apparatus for detecting cracks in telephone switchboards while the second deals with the detection of cracks in hard lubber battery boxes. A novel patent (64)deals with spraying heated powdered ebonitc on a metal and producing a satisfactory bond on impact. Miscellaneous patents cover the use of hard rubber in such items as handles for hoes ( 6 ) ,bearings for fluid meters i7), syringe tubes (9),packing assemblies for drill shafts in oil wells ( I O ) , e1ect)ric pin plug connectors ( l a ) ,crawl-fins (IC),preserving jar seal ($11, improved valve for controlling the flow of finely divided powders (B)spongelike , ebonite (Sd), valve for liquid fuel gases (%), smoker's pipes (s6), inking !"8), a multipurpose (SQ),a rhythm stick for st,riking the strings of a mueicial instrument ( 4 S ) , cigarette holder (&), reinforced conduits (46), a luring device for hunting geese (is),spool for dyeing nylon (@), Of laminar construction (61 ), pulley for rotary pumps (58), conveyors (64),and an electldytiC cell for deposition Of gold and eilvcr (67). LITERATURE CITED (1) Anierican Hard Rubber Co., Brit. Patent 674,608 (1952). ( 2 ) American Hard Rubber Co., 9 Mercer St., New York 13, S . Y.,
(3) (4) (5) (6)
Bull. 96-A, 1953. American Hard Rubber Co., Rubber A g e , 72, 653 (1953). Anchor Chemical Co., Ltd., Manchester, Englandi Bull. (1952). Barack, hl., Brit. Patent 664,003 (1952). Barker, W.A . , and Dempster, RI. O., ..lustral 83
(1953). (7) Bergman, C. P., and Elliott, W. U. S. Patent 2,607,640 (1952). (8) Bourgois, P., and Plantier, J., Rev. o h . caoutchouc, 29, 914 (1952). (9) Brown, G. D., U. S. Patent 2,631,333 (1953). (10) Cameron Iron Works, Inc., Brit. Patent 681,312 (1952). (11) Clausen, J. F., Rubber (DeZit), 8, 119--21 (1952).
v.,
(12) (13) (14) (15) (16)
(17) (18) (19) (20)
(21)
2113
Court, R. A. R . , Brit. Patent 684,915 (1952). DaTies, B. L., I n d b R u b b e r J . , 124, 96 (1953). de Corlieu, L. M., U. S. Patent 2,588,363 (1952). de Atun& Y , , Ibid,, 2,621,221 (1952). de Vries, 9. J., Gummi u.Asbest, 5, 310 (1952). Duvivier, C., and Hedde, F., Rev. ghn. caoutchouc, 29, G i l (1952). Electric Storage CO., IJtd., Brit. Patent 672,733 (1952). Expanded Rubber Co., Ltd., Croydon, England, Bull. (1953). Fieltj, B, R , ~ ~patent i 680,73g-41 ~ , (1952), "Glabus," Gummi und Asbestwerks, German Patent 814,379
(1951). ( 2 2 ) Goodyear Tire and Rubber Co., Rubber Age, 73, 593 (1953). (23) Grouch, G. E., J . Phys. Chern., 55, 1279-85 (1951). (24) Ozclnlrziu,dsbest, 5, 136-7 (1952). (25) Hansen, L. D., and Overmyer. D. E., U.S. Patent 2,623,100 (1952). (36) I1er111eling, W.3 Che'm. Tech. (Bedin), 4, 554-8 (1952). (27) FIersch, P., Brit. Patent 688,991 (1953). ( 2 8 ) Hood, R.S,, s. Patent 2,604,246 (1952), (29) IIouwink, K., Kautschuk u. Gummi, 5 , WTGO (1952).
u.
(30 Houwink, R.,de Vries, -4. J., and Wout, J. W. F., van't, Gu?nmi ZL. Asbest, 6, 104 (1953). (31) Hubertz, H. P., U.S. Patent 2,615,964 (1952). (32) Inter Services Plastics Panel Rept., H. h i . Stationary Office, London, (1951). (33) Jenkins. 13. F. L., Brit. Patent 693,191 (1953). (34) Kitalnura, S. K., and Nagashima, T., Japan, Patent 174,853 ('52) (1952). (35) K,illkellberg, O., Brit. Patel,t 682,839 (1952). (36) Levietes, D. P., Ibid.,664,442 (1952). (37) Lepetit, F., Res. ghn. caoutchouc, 30, 256-61 (1953). (38) Levey, F. H.$Brit* 6897068 (1953). (39) Lupo, M., U. S. Patent 2,616,435 (1952). (40) Luttropp, H., Chern. Tech. (Berlin),5, 229-33 (1953). (41) KIcNamee, J. P., ~ r i t ~. b s t r BII, . 1950 (1952). (42) Madge, E. W., and Purkis, F. T., Brit. Patent 658,296 (1951). (43) hlasseyi E. E., u. Patent 296207701 (19b2). (44) Miller, J. C., U. S. Patent 2,607,353 (1952). (45) Nornian, -4.E., Brit, Patent 660,254 (1951). (46) Olt, p. s.,u.S. Patent 2,606,400 (1952). I" (47) Parbrook, H. D., J . Sci.Instr., 30, 26-7 (1953). (48) Persoz, B., Reo. 06% caoutchouc, 30, 492-8 (1953). (49) Pownall, L., Brit. Patent 693,839 (1953). (50) Rubber-Stichting, Delft, Holland, Bull. 6-21, 30 (1951). (51) Rubber-Stichting, Chem. ~ nI\rews,~ 30, . 1944 (1952). (52) St. Helms Cable and Rubber Co., Ltd., Chem. & Process Eng., 33, 285 (1952). ( 5 3 ) St. Helens Cable and Rubber Co., Ltd., Slough, p. 6 (1952). (54) Smith, F. W., and Matter, ,J. K., Machinist, 97, 1742-3 (1953). (55) Smith, S.R., Brit. Patent 663,520 (1951). ( 5 G ) Thomas, L. J., Brit. Patent 671,735 (1952). (57) U. K., Dept. of Scientific and Ind. Research, Kational Physical Lab. .l'otes on A p p l . Sci.,H. LI. Stationary Office, London, IV, 16 (1952). ( 5 8 ) Tanton Pump Corp., Brit. Patent 671,094 (1952). (59) Vickers, H. J. S.,Rubber A g e and Synthetics, 33, 297 (1952). (GO) U'aeser, B., Gummi u.Asbest, 4, 406-9 (1951). (61) Wareing, R. J., Brit. Patent 672,144 (1952). (62) Warring, R. H., Machinery Lloyd, 25, S o . 9, 68-70 (1953). (63) Weinbrenner, E., Chem. Ind. (DiisseZdorf), 111, 613-6 (1951). (64) Wittkop. E., German Patent 818,755 (1951). (65) Wout, J. W. F., van't, Rubber Age, 70, 753 (1952). (GG) Yoshida, S.,Japan. Patent 133('51) (January 23, 1951). (67) Zadra, J. B., U. S.Patent 2,563,903 (1951).
COURTESY ATLAS MINERAL PRODUCTS CO.
Injection iMolded Threaded Pipe Fittings of Unplasticized Polyvinyl Chloride (See Plastics p. 2135)
