. 1002
INDUSTRIAL AND ENGINEERING CHEMISTRY
tion of residual oil from epent catalyst. h variety of solvents were used, including aliphatic and aromatic hydrocarbons, alcohols, and chlorinated solvents. The color of the extracted oil depended on the nature of the solvent used. Thus, Skellysolve F yielded a light yellow extracted oil, and chlorinated solvents gave a deep red-orange extract owing t o more complete removal of coloring matter adsorbed during the isomerizations. The pale, recovered oil could be incorporated into the conjugated oil, whereas a dark, extracted oil was regarded as a by-product. T h e extracted catalyst was pyrophoric. The nickel contained in the oil-free catalyst was extractable and recoverable b y any suitable method. I n laboratory experiments extraction with nitric acid resulted in recovery of 90% of the original nickel. ACKNOWLEDGJIEKT
Grateful acknowledgment is made t o E. H. SIelvin, R. J. Berte, and R u t h &I.Johnston of the Analytical and Physical-Chemical Division of this laboratory for the many spectroscopic analyses performed during this research; t o A. J. Len.is and Helen A. hIoser for the evaluation tests; and t o R. E. Beal and W. H. Goss of t,he Engineering and Development Division for filter cost estimates. We are also grateful to West Yirginia Pulp 6: Paper Company, American S o r i t Company, Darco Corporation, Godfrey L. Cabot, Inc., The Harshaw Chemical Company, JohnsManvillc Corporation, The Dicalite Company, Central Soya Company, Archer-Daniels-hlidland Company, Spencer Kellogg 8; Sons, Inc., and Industrial Filter and Pump SIanufacturing Company for their generous cooperation in contributing samples of the various materials used in this investigation. The mention in this article of firm names or commercial products under proprietary names or names of their manufacturers does not constit u t e an endorsement by the U. S. Department of Agriculture of such firms or products.
Vol. 38, No. 10
LITERATURE CITED
(1) ildkins, H . B., “Reactions of Hydrogen”, p . 19, Madison, Univ.
of Wis. Press, 1937. (2) Bauer, K. H., and Ermann, F., Chem. Cmschuu Fette, Ole, Wachse Harre, 37, 241 (1930). (3) Bradley, T. F., U. 5.Patent 2,350,583 (June 6. 1944). (4) Bradley, T. F., and Richardson, D., IND.Ewc;. CHEM.,32, 963 (1940). (5) Ibid., 34,237 (1942). (6) Burr, G. O., U. S. Patent 2,242,230 (May 20, 1941). (7) Dijk, J. A. van, Allgem. Oel- u. Fett-Ztg., 28, 277 (1931). ( 8 ) Forbes, V.C., and Neville, H. A., IKD.ENG.CHEM.,32, 556 (1940). (9) Hilditch, T. P., and Rhead, 4.J., J. Soc. Chem. I n d . , 51, 198T (1932). (IO) Hilditch, T. P., and Vidyarthi, N. L., Proc. Roy. Soc. (London), A122, 552 (1929). (11) Kass, J. P., in Mattiello’s “Protective and Decorative Coatinga”, Vol. IV, Chap. 12, New York, John Wiley & Sons, Inc., 1944. (12) Kass, J. P., and Burr, G. O., J. Am. C h a . Soc., 61, 3292 (1939); 62, 1796 (1940). (13) Levev. H. .L, U. S. Patent 1,374,589 (1921) (14) Lewkowitsch, J., and Warburton, G. H., “Chemical Technology and Analysis of Fats and Waxes”, 6th ed., Vol. I, p. 196, London, Macmillan & Co., Ltd., 1938. (15) Mattil, K. F., Oil & Soap, 22, 213 (1945). (16) Moore, C. W., J . Soc. Chem. I n d . , 38, 320T (1919). (17) Sabatier, P., Ber., 44, 1934 (1911). (18) Spitzer, W. C., Ruthruff, R. F., and Walton, W. T., Am. Paint J . , 26, NO. 12, 68-72 (1941). (19) Suzuki, T., and Kurita, R., Sci. P a p a s I n s t . Phys. Chem. Research (Tokyo), Suppl. 9, 5 (1928). (20) Turk, d.,and Boone, P. D., Oil & Soap, 21, 321 (1944). (21) Turk, A . , and Feldman, J., Paint, Oil Chem. Rev., 106 (13), 10 (1943). (22) Waterman, H. I., and Dijk, J. A. yan, Rec. trau. chim., 50, 279, 679 (1930). (23) Katerman, H . I.. and Tussenbroek, b l . J. van, Chem. Weekblad, 26. 566 (1929): 27. 146 (1930). (24) Waterman, H. I., and Vlodrop, C. van, J. Soc. Chem. I n d . , 55, 320T (1936). ( 2 5 ) Waterinan, H. I., and Vlodrop, C. van, Xec. trau. chim., 57, 629 (1938). I~
(Catalytic Isomerization of Vegetable Oils)
EVALUATIOY OF OILS IN BODYING, VARNISHES AND ALKYD RESINS L . B . Falkenburg, A . W . Schwab, J . C . Cowan, and H . M. Teeter T h e bodying rate of nickel-carbon isomerized linseed oil is three to five times as fast as that of the alkali-refined oil, and the rate for isomerized soybean oil is two to three times as fast as that of the alkali-refined oil. The bodied isomerized oils have lower acid numbers and better color than the bodied, alkali-refined oils. Losses during bodying are lower with isomerized oils. Comparisons between nickel-carbon isomerized linseed and soybean oils, dehydrated castor, linseed, and soybean oils w-ere made with a series of varnishes and with alkyd resins. Time of rook, drying time, resistance to hot and cold water and to alkali, and hardness of the film are reported for the varnishes and resins. &lain advantages of these new oils are found in rapid cooking schedules and increased alkali resistance.
I
N THE first paper of this series, a potentially economical and
practical method for the isomerization of vegetable oils by means of neutral oatalysta offers promise of new raw materials for t h e paint and varnish industry (6). The oils treated with niakel-carbon catalyst contain 26-3370 total conjugation and
have low acid value, color indices, and viscosities. I n these three latter respects, and in contrast t o oils produced by the alkali isomerization process, these new oils approach more nearly the properties of dehydrated castor oil. I t is of importance, tliprefore, to obtain a thorough understanding of their physical and chemical propeities, and t o evaluate their derived products so t h a t their relative positions among drying oils may be determined. This paprr is concerned with the polymerization of these new oils and with a preliminary evaluation of varnishes anti alkyds derived from them. The unusual polymerization ratm of these new oils justifies special attention to their polymerization. The paper includes information on polymerization rates of the isomerized oils and on the comparison of these rates with the polymerization rates of dehydrated castor oils and thc naturally occurring oils from which they iwre prepared. Also, of primary interest t o the paint and varnish research workers, a few representative varnishes and alkyds were prepared from both isomerized and nonisomerized linseed and soybean oils and dehydrated castor oil, and films of these protective coatings were evaluated for drying time, hardness, water and alkali resistance.
I
Figure 1.
1003
INDUSTRIAL AND ENGINEERING CHEMISTRY
October, 1946
2
3 4 TIME.HOURS
5
6
Bodying of Linseed and Dehydrated Castor Oils
Dehydrated castor oil was included for comparative purposes in both film evaluation and polymerization studies since it constitutes the only widely used synthetic drying oil containing an appreciable amount of conjugation. The oils were not compared directly with tung oil because their composition with respect to kind and amount of conjugated and nonconjugated fatty acids is much different. Polymerization experiments were conducted on isomerized and alkalirefined linseed oils under carbon dioxide and in vacuum, to determine bodying losses and to gain a n insight into the comparative behavior of the tTTo oils when bodied in a vacuum. The industrial importance of this method of polymerization is increasing.
Samples \Tere viithdrawn a t regular intervals for the determination of viscosity, acid value, color, and refractive index. The data obtained from these polymerization runs are listed in Table I1 and in Figures 1 and 2 . Polymerizations of alkali-refined and isomerized linseed oila were also conducted under vacuum. The oils were bodied in apparatus of the type described, except that a vacuum line was substituted for the carbon dioxide inlet. Samples of the oil were first degassed, then heated t o the desired temperature a t a pressure of approximately 1 mm. Each sample of oil was held for a definite length of time, then cooled and analyzed. A comparison of the bodying characteristics of alkali-refined and isomerized linseed oils under carbon dioxide and in vacuum is shown in Table 111. Viscosities were determined a t 25" f 1a C. by meam of a Gardner bubble viscometer. The time (in seconds) required for t h e bubble to rise in a standard tube gave the absolute viscosity ( 9 ) . Colors were measured by comparison with Gardner color standards; acid values were obtained by dissolving a sample in 50 cc. of a mixture of equal volumes of benzene and 95% ethanol and titrating with 0.1 S potassium hydroxide and phenolphthalein as indicator. GRAPHSASD CALCCLATIONS.For L comparison of the rates of polymerization of the isomerized and natural oils, the viscosities of the samples withdrawn during the bodying rum were plotted against time on semilogarithmic paper. It has been shown previously that this type of plot produces nearly straight lines, the slopes of which are indicative of the rates of polymerirstion ( 4 ) . The zero time in each case was taken a t the moment when the oil reached the specified temperature. Figure 1 showe the curves obtained from the data for the isomerized and non-
TABLE I. ANALYSISO F OILS USED Oil Alkali-refined soybean Alkali-refined linseed Iaomerized linseed Isomerized soybean a
Color (Gardner) 5
3 4 3
Acid Value 0.5 0.4 0.65 0.5
IS POLYMERIZATION STIJDIn8
Ab?. Viscosity, Poises Acid Value 1.1 3.0 5 4 7.4 0 8 2.4 4 0 4.7 5 0 2 7 10.3 16.4 24 8 73 6 33.6 1.5 6.0 16 4 20.0
4
0 8 2 5 3.5 5 4
3
0.7
9-3 3 3
1 6
2 2 1.4 8 0
2-3 2 2 2 3-4
0.05 0 . i,i 1.0 1.3
DISCUSSION.The rates of polymerization of the isomerized oils are very much greater than those of the alkali-refined oils from which they were prepared. For example, a t 590" F. the polymerization rate of isomerized linseed oil is three to five times as great as that of the original oil, whereas the rate for the isomerized soybean oil is two t o three times t h a t of the alkali-refined oil. These results were to be expected since conjugated double bonds are known to polymerize a t a much greater rate than nonconjugated double bonds. However, the rates of polymerization of these new oils cannot be expected t o approach those of the naturally occurring conjugated oils, tung and oiticica; not only d o the latter contain a much greater percentage of total conjugation, but also the conjugation is triene, whereas that present in the isomerized linseed and soybean oils is principally diene. It is also of interest to compare the polymerization rates of the isomerized linseed and soybean oils with t h a t of dehydrated castor oil which usually contains about 15 t o 22% total conjugation (6). Figure 1 s h o w that' the bodying rates of isomerized linseed and dehydrated castor oils may be considered about equal. On the othcr hand, Figure 2 demonstrates t h a t dehydrated castor oil, although it contains less conjugation, has a much faster polymerization rate than that possessed by isomerized soybean oil. This faster rate is unquestionably due to the higher proportion of polyunsaturated fatty acids present in dehydrated castor oil (80 to 83%) as compared with soybean oil, which contains about 40 to 60CGof these constituents (8). However, by the neutral isomcrization procedure, soybean oils can be prepared vi-hich polymerize a t the same rate as alkali-refined linseed oil.
0.7 1.0 l.% 1.4
2
3-4 4
TABLE IV. RELATIVEBODYING RATES
isomerized linseed oils. Curves for dehydrated castor oil, plotted from the data of von Mikusch ( d ) , are included for comparison. Similarly, the curves for the various soybean oils are given in Figure 2 . In order to obtain a clearer comparison of the polymerization rates, the times rcquired for bodying the oils from an initial viscosity of 2 poises to viscosities of 15 and 46.4 poises were calculatcd from Figures 1 and 2. I n the event that an oil had a viscosity greater than 2 poises by the time the desired temperature of polymerization was reached-for example, Isomerized linseed oil polymerized a t 560" F.-the value was found by extrapolation. The results are listed in Table I\' and are referred to results for linseed oil which are taken as unity. From these data a plot on semilogarithmic paper was made of the time required t o increase the viscosity of a n oil from 2 to 15 poises between 560" and 590" F. (Figure 3). A comparison of the bodying rates of the diffcrrent oils at any given temperature within this interval may be made by noting the relative heights at' which the curves cross a chosen temperature ordinate. The doubling intervalthat is, the number of degrees by which the temperature of an oil must be raised in order t o double the rate of polymerization-was calculated from the curves for each oil. These values are given in Table V.
Oil Isomerized linseed Dehydrated castor Isomerized soyhean Slkali-refined linseed Alkali-refined soybean
Relative Times Required to Body Oil from: 2-15 Poises at:_ 2-46.4 poises a t 590' F. 560' F. 5900 I?. 0.21 0.37 0.22 0.39 0.35 0.27 0.93 0.72 1.01 1.00 1.00 1 .00 2,23 2.43
..
TABLE I-. DOCBLISGINTERVALS FOR VISCOSITY INCREASE 2 TO 1.5 POISESFOR TEMPERATURE RANGE569-590' F. Oil Isomerized linseed Alkali-refined linseed Dehydrated castor Isomerized soybean
Doubling Interval, 13.5 23.0 27.5 35.0
OF
OF.
The data of Table I1 confirm the fact that an oil bleaches during the early stages of heating and then becomes progressively darker (2). Since this bleaching occurs early in the polymerization process, rapid-bodying oils are decidedly advantageous in obtaining light-colored oils of high viscosity. For example, if an oil of approximately 60 poises is desired, isomerized soybean oil bodied at 590' F. under carbon dioxide would yield a product having a color of 4 (Gardner) ; under identical conditions, on the 0tht.r hand, an alkali-refined oil would yield a product possessing a color of 7 . Similarly, the faster a n oil polymerizes the better the chances are for ob1,aining an oil of low acidity a t any particular viscosity. I n the case of the soybean oils a t a viscosity of approximately 60 poises, the isomerized oil has an acid value of 7.4 whereas that of the TABLE 111. PROPERTIES O F LINSEEDOILS BODIEDTjNDER, C.4RBOS alkali-refined oil is over 31. The isomerized ljnseed DIOXIDE .OD IK VACUIW oil produces bodied oils of superior color and lower -Alkali-Refined LinseedIsomerized LinseedUnder c02 Under mm. Hg Under cos Under mm, sg acidity than the alkali-refined oil when polymerized 530" F. 5950 F. 5950 F.5950 F. 5300 F. j g j o F. 5300 F. 5300 F. either under carbon dioxide or in a vacuum (Table
--
~~~
Time, hours Abs. viscosity, poises Color (Gardner) Acid value Bodying loss, Yo
10 8 318
..
6.5 161 6
16.5 4.1
3 35 3-4 1.7 8.8
4 290 5 2.8 11.0
8 90 1 2.9 1.3
1;75 140 3 5.9 1.4
5 5 64
2 0.9 1.5
6.75 220 2 1.0 1.8
111). A study of isomerized and alkali-refined linseed oils, bodied under carbon dioxide and in vacuum, shows that both oils polymerize more rapidly under reduced pressure (Table 111). This may be an
TABLE
VI.
Source
Alkali-refined linseed Dehydrated castor Isomerized soybean Isomerized linseed Bodied linseed Bodied dehydrated castor Bodied isomerized soybean Bodied isomerized linseed
Procti Baker North Northern Regional Spencer Kellogl Sherwin-Fillia. Northern Regional Rese h-orthern Regional Research
Color (Gardner) 10 6 6 3 5 3 4 4 3
TABLE VII. RESINSVSEDIN VARNISHES Resins Bakelite BR-254 Arnberol B S / l
General Type 100% phenyl phenolic Modified phenolic
Arochem 400 Eater gum Bakelite UR-3360
hlodified phenolic Glycerol abietate 100%, phenolic (heat reactive) 5% lime, 2% ZnO
Manufacturer Bakelite Cow. Resinous Products & Chemical Co., Inc. Stroock & Wittenberg Corp. Hercules Powder Co. (Inc.) Bakelite Corp. Northern Regional Lab.
VARNISH STUDIES
Five series of varnishes, each containing a different resin, were prepared according t o methods recommended for dehydrated castor oil by the resin manufacturer. Each varnish was tested for color, cooking speeds, drying time, hardness, and resistance against hot and cold water and alkali. U7hen naphthenate-type driers were added, the percentage of metal added was based on the weight of oil in the varnish. ~IATERIALS.The isomerized oils employed in this study were prepared from alka1i;refined linseed and soybean oils using a nickel-carbon catalyst a t 170" * 2" C. (3). Samples of the same alkali-refined oils were also utilized for the preparat,ion of varnishes. The bodied isomerized oils of the desired viscosity were prepared by polymerization a t 560" F. under carbon dioxide, whereas the dehydrated castor oils and bodied linseed oil were commercial samples. The physical constants of the oils are given in Table VI. All of the resins were commercial samples, except the treated rosin (Table VII). The treated rosin was prepared according t o the folloxving formula and procedure: 1532 grams. of rosin were heated t o G O " F., and a mixture of 76.6 grams of calcium hydroxide and 30.6 grams of zinc oxide was sifted in slo~vly. The temperature was then raised slowly t o 52.5' F. and held for 3 hours. The rosin was poured into a shallow pan and cooled. Brief details VARKISHFORMULAS ASD COOKING PROCEDURES. of the procedures used are given in the following paragraphs, and the formulas and procedures are summarized in Tables VI11 and I S . Physical constants of the varnishes of each series are listed in Table X. Series A, of 20-gallon oil length, was a modified phenolic: 350 grams 200 grama 600 grame
Oil Bakelite BR-254 Thinner
355 grams 140 grams 400 g r a m
Research
apparent change in the rate of polymerization of the oils caused by the continuous removal of volatile acids and other decomposition products when the oils are heated under reduced pressure. Rlien these products are allovr-ed to remain in the oil, they cause a reduction in viscosity. The bodying rate is related to acid value, and large concentrations of acids result in a marked retarding effect (1). The isomerized linseed oil exhibited a much lower bodying loss than t,he alkali-refined oil when bodied either under carbon dioxide or under reduced pressure. Polymerized oils are used widely in the preparation of paints, enamels, varnishes, printing inks, grinding vehicles, core oils, lubricants, and ot,her materials. The catalytically isomerized oils should have a decided advantage over the alkali-refined oils for the preparation of bodied oils, for their use would effect a substantial saving both in time and in processing costs, and would yield products possessing better color and lower acidity.
Oil Amberol B S / l Mineral spinta
All of the oil and resin was heated in a lyliter beaker to Viscosity Conju570" F. This temperature waa (GardnerAcid gation, held until a 12- to l 4 i n c h string Holdt) Value 5% from a cold plate was obtained. A 0.14 10.1 G-H 22: 1 The heat was then removed, C 0.6 32.4 C 0.6 30.9 and the varnish was allowed z1 2.0 ... . t o cool t o 320" F.; i t was rez1 3.3 z1 5.5 duced with mineral spirits a t z1 4.0 t h a t temperature. For testing, the varnishes were reduced t o a n A viscosity, and 0.3% lead, 0.03% cobalt, and 0.02% manganese were added. Series B, of 30-gallon oil length, was a 100% p-phenyl phenolic:
OILS USED FOR PREPARATION O F VARNISHES
Oil
Treated rosin
1005
INDUSTRIAL AND ENGINEERING CHEMISTRY
October, 1946
Thinner consisted of 60 parts mineral spirits, 30 parts Hi-Flash naphtha, and 10 parts toluene, by veight. All of the oil and rcsin wils heated to 300" F. and held for 1 hour. The temperature vas raised to 430" F. and held for 2 hours, raised to 500" F. and held for an additional hour, and then 570" F. was gained in 30 minutes. The cook was held for a 12inch string from a cold plate, cooled to 350" F., and cut with the thinner. Tlicse varnishes were reduced t o a D viscosity, and 0.3Y0 lead, 0.037, cobalt, and 0.027, manganese driers were added. Series C, of 25-gallon oil length, Tvas a modified phenolic: Bodied oil (Z1 viscosity) Arochem 400 Mineral spirits
341 grams 178 grams 500 grams
All of the resin and oil was heated to 580 a F. and held for a %foot cold string from a glass plate. The varnish was then cooled to 3.50' F. and reduced with the thinner. The varnishes were reduced to a D viscosity, and 0.2% lead and 0.037, cobalt were added. Series D, of 25-gallon oil length, was a 100% heat-reactive phenolic-ester gum: Oil Bodied oil Bakelite BR-3360 Ester gum Mineral spirits
253 grams 85 grams 18 prams 160 g r a m 500 g r a m
All of the ester gum was heated t o 450' F., and the Bakelite resin vias then added (off the fire). When the Bakelite had dissolved, the mixture was taken to 300' F. and held for 30 minutes, then 500 O F. was gained in 10 minutes and held for 20 minutes. The unbodied oil was added, and the cook was taken to 560" F. in 15 minutes and held a t this temperature for 45 minutes, then raised to 585' F. and held for 40 minutes. The bodied'oil was added, and the temperature v a s held a t 560' F. for a 2-foot string off a cold plate. For testing, these varnishes were reduced t o an E viscosity, and 0.3% lead, 0.037, cobalt, and 0.02% manganese were added. Series E, of 52-gallon oil length, was a treated rosin: Bodied oil Treated rosin Mineral spirits
380 grams 88 grams 450 grams
The oil was heated t o 595' F. and held for a 4-inch hot string; the resin was then added as a check. The varnish was cooled to 350" F., reduced with mineral spirits, and filtered. The varnishecl were reduced to a n E viscosity, and 0.5% lead and 0.05% cobalt were added. The testing procedures used were as follows:
DRYIN(;Trim. The drying rates of the varnishes were determined with the Sanderson drying meter (?), and the results are given in Table X I . COLD XATER RESISTANCE. Films of the varnishes were flow-coated on standard tin panels which had been thoroughly cleahed with benzene. The coated panels were allowed to drain
1006
INDUSTRIAL AND EN G INEERING CHEMISTRY
Vol. 38, No. 10
TABLEVIII. VARNISH TYPESA N D COOKINQPROCEDCRES Series
A B
20
D
30 25 25
E
52
C
.
Oil Length, Gal.
Resin Used
Oil-Resin Combination
hmberol BS/1 Bakelite R.R. 254 Arorhem 400 Bakelite B.R. 33FO ester gum
Combined cold Combjned cold Combined cold Ester gum heated, Bakelite dissolved, unbodied oil added, bodied oil added Resin used to c h e c k oil bodying
+
Limed rosin
TABLE
1s.
Oil 4, alkali-refined linseed hIin. t o top temp. Min. held a t top temp. Total time. min. ?din. after addn. of bodied oil
Cooking Temp.,
12-14 12 36 24
570 300-570 5 80 45')-660
F.
O
Varnish NO.
A-1 A-2 '4-3 A-4 B-1 B- 2 R-3 B-4 C-1 c-2 c-3 c-4 D-1 D-2 D-3 D-4 E-I E-2 E-3 E4
Varnish Series B
57 98
..
2 80 70 60
Varnish Varnish Series C Seriea D
.. ..
57 83
..
..
.. ..
..
40
..
19 68
.. .. ..
80 25
.. ..
40 160
..
4io
..
..
..
40 145
..
4j2
..
t .
Vamish Series E
40 72
..
36b
Nonvolatile LIatter,
c/o
E
E
44.0 38.0 44.0
A
A
A D D B D
n
D
2 E
E li
1
585
4
2s:
54.6 53.6 55.4 54.8 56.3 55.6 53.3 58.5 49.7 55.0 55.0 52.4 51 . O 54.0 53.0 51.0
A
isomerihd Soybean Oil
+
h
..
80 250
..
..
..
240
49 81
..
..
41.0
Color (Gsrdner) 12-13 12 14 13-14 13 12 12 13 12-13 13-14 13-14 12 18
