May, 1941
I N D U S T R I A L AND E N G I N E E R I N G CHEMISTRY
629
(12) Holt and McPherson, Rubber Chem. Tech., 10,412 (1937). (13) Karrer, Phys. Reo., 39, 857 (1032); Protoplasm, 18, 475 (1933). (14) Mack, J . Am. C h m . SOC.,56,2757 (1934). (15) Meyer and Ferri, Helv. Chim. Acta, 18,270 (1935). (16) Meyer and Mark, Ber., 61,1939 (1928). (17) Meyer, Susich, and Valk6, Kolloid-Z., 59,208 (1932). (18) Mooney, Rheology Symposium, Akron, Ohio, 1937; J. A p p l . Phys., 11, 582 (1940). (19) Ornstein, Eymers, and Wouda, Rubber Chem. Tech., 3, 403 (1930). (20) Shacklock, Ibid., 6,486 (1933). (21) Sheppard and Clapson, Ibid., 6, 126 (1933). (22) Vogt, in Davis and Blake’s “Chemistry and Technology of Rubber”, pp. 338-51 (1937). (23) Ibid.. DD. 351-7. (24j Whitd;, “Plantation Rubber and its Testing”, 1920. (25) Wiegand and Snyder, Rubber Chem. Tech., 8, 151 (1935). (26) Williams, Ibid., 12, 191 (1939). (27) Wohlisch, Verhadl. physik.-med. Ges. WWzbuTg, 51, 53 (1926).
A detailed discussion of the extended statistical model of rubber, with a number of applications not mentioned here, will be published elsewhere.
Literature Cited (1) Boggs and Blake IND.ENG.CHEM.,22,748 (1930). (2) Boissonas, Zbid., 31, 761 (1939). (3) Brown and Hauser, Ibid., 30, 129 (1938). (4) Busse, J. Phys. Chem., 36, 2862 (1932). (5) Fikentscher and Mark, Kautschuk, 6,2 (1930). (6) Fisher, IND.ENG.CHEM.,31, 1381 (1939). (7) Fisher and Gerke, in Davis and Blake’s “Chemistry and Technology of Rubber”, p. 114,A.C. 5. Monograph 74. New York, Reinhold Pub. Corp., 1937. (8) Garvey, IND. ENG. CHEM.,26, 437 (1934). (9) Guth, Kautschuk, 13, 201 (1937); Guth and Mark, Monatsh., 69, 93 (1934). (9A) Guth and James, Div. of Rubber Chem., A. C. S., Detroit, (11) Hock, i n Memmler’s “Science of Rubber”, New York, Reinhold Pub. Corp., 1934.
PR~SBJNTBID before the Division of Rubber Chemistry at the 98th Meeting of the American Chemical Society, Boston, Mass.
DICHLOROSTEARATES AS DRIERS WILLIAM HOWLETT GARDNER AND
RUSSELL B. WADDELL Polytechnic Institute, Brooklyn, N. Y.
Cobalt, lead, and manganese dichlorostearates have the same efficiencies as the respective naphthenates as driers for oils and varnishes. No difference was observed in their possible effect upon the drying reactions of various vehicles. This would indicate that the chlorinated fatty acid radical has no effect upon the catalytic properties of these soaps. HE cobalt, lead, and manganese soaps of 9,lO-dichlorostearic acid have many of the general characteristics described by Bruson and Stein (6) for the ideal type of compounds to be used as driers in paints and varnishes. Since they contain a chlorinated fatty acid group, it was of added interest in determining their properties as siccatives to ascertain what effect, if any, this radical might have in promoting their behavior as catalysts. The dichlorostearates were therefore compared with corresponding commercial driers as to their effect upon the drying properties of four different types of vehicles.
T
Action of Driers Little is known in regard to the precise manner in which driers take part in the reactions of oils and varnishes, other than that they accelerate the oxidation and polymerization of these materials. There are many reasons for viewing driers as the promoters in preference to true catalysts in these reactions. Some investigators have suggested that they may function as stabilizers for the autocatalytic peroxides which are formed during the initial drying reactions (8, 11, 66). Others (62) have viewed them as agents which destroy in-
The vehicles studied showed striking differences in their drying characteristics when the various metal siccatives were added to them. These differences can be explained only by assuming that the driers enter into the catalyzed reactions. The formation of possible unstable metal coordination compounds has been suggested to account for the observed effects. hibiting substances with reducing properties. Measurements of the rate with which oxygen is consumed during drying has clearly shown that driers shorten the induction period during which the autocatalysts are formed. Stephens (6%‘) produced a similar effect in the oxidation of cyclohexene by highly purifying that material. The same type of shortening of the induction period of oils can also be accomplished by elevating the temperature without adding driers. Inhibitors such as phenolic substances, in contrast, increase the induction period. Rogers and Taylor (0’6) showed that these reducing substances when added to an oil suppressed both the effectiveness of driers and of the natural catalysts formed during oxidation. Oxidation reactions alone, however, will not lead to a dry film. It is necessary for an oil or varnish film to form a gel in order to produce a hard coating. Some years ago Long (30) and Wolff (66) pointed out the importance of polymerization and association reactions in obtaining this useful state. This led investigators to conclude that conjugated ethylene bonds were necessary for polymerization ($1, 29, 33, 36,66-60, 63,66). Conjugation unquestionably has an important influence upon the drying reactions (23, 24, 36-
630
INDUSTRIAL AND ENGINEERING CHEMISTRY
EFFECT OF
16 14 12
I.o 0.6 06 04
0.2 TIME
TO D R Y
-
HRS.+
0
1.
2.
Raw oiloil Bodied
3. Phour Floor varnish varnish
4.
$9,@), but as Bradley suggested (1,S), the important factor is the active functionality of the reacting molecules. An outstanding example is the drying properties of the trioleyl ester of shellac (1) and those of polyfunctional long-chain sub-
stances (26, 64) where unsaturation is necessary only a t intervals in the molecules to obtain drying. The small amount of oxygen required to convert polytriethylene maleate to a gel illustrates how easily oxidation can lead to polymerization and association when the proper functionality exists. Morrell and Phillips suggested that in the drying of vegetable oils by oxygen conversion, oxygen is attached a t the ethylene bonds farthest removed from the glyceride radical to give a peroxide capable of polymerization (39). Heat conversion, in contrast, involves a diene polymerization and then an intramolecular reaction (4, 6, 39). It is possible that driers form coordinated compounds (44)with many of the substances present during these reactions. GebauerFuelnegg and Konopatsch demonstrated (16) that a compound must react with an oil in order to function as a drier. Long undoubtedly had the basic concept of coordinated compounds in mind (18) when he wrote that oil molecules might be oriented by driers during the drying reactions. The color changes observed with cobalt driers are indicative of the formation of such coordinated substances in the oil films during drying. Driers may react with the oil either through double decomposition, as was the case with the compounds studied by 14
I2 10
6
4 2
5 0 0
u s
+ e Y
0 4 L W 0-2 0
.e IO
e 8 4 2
0
F I G 3. OXIDATION OF B O D I E D O I L
1. Total oxygen absorbed 2. Total net gain in weight 3. Total loss of volatiles, including 0.8 per cent naphtha and 7.2 per
cent mineral spirits
0
10
-
20
10
flG.2.
OXIDATION OF R A W O I L
40
TIME
$0 HRS.
60
70
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May, 1941
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
Gebauer-Fuelnegg and Konopatsch, or directly with the oil as is probably the case with ordinary commercial driers which are not saturated from a coordination standpoint (16). The formation of stable metallocomplexes would undoubtedly destroy their catalytic properties. Hence, they probably form only unstable compounds and thus do not add to the functionality of the oil molecules. The observation (20)that zinc soaps can form stable complexes might readily account for poor siccative properties of salts of this metal and the effects which the presence of such soaps have upon drier activities. The valence state of the metal radical unquestionably would have an important influence upon the type and stability of the complexes formed, but it would not be essential that the metal radical should be capable of existence in more than one valence in order to impart siccative properties (27). The skinning effects caused by cobalt driers when varnishes are stored in cans and the effect of antiskinning agents when used in large quantities are further evidence that unstable complexes may be formed by driers. These reactions involve physicochemical aspects of surface oxidation. This is a subject which has not been given enough study.
Factors Affecting Drier Efficiency Consequently a relatively large number of factors can influence the effectiveness of a drier. Some of these factors are external conditions such as light (17,40, 61),temperature, and moisture (14,19, 30, 61). Other factors include the nature and history of the vehicle (dQ), the peroxide content of the vehicle @7),the amount of free fatty acids present (2@, the effective concentration of the drier (40,66), the particular metal radical of the drier employed (13, 22, 26, 31, 32, 43), and the presence of other metallic substances (27)in the oil. Failure to duplicate any one set of conditions exactly when comparing one drier with another may lhus easily lead to erroneous results. The fact that various investigators have not always agreed in their findings when comparing drier efficiencies can readily be explained by assuming that they have overlooked one or more of these important factors. Temperature, for example, has a marked effect upon the type of reactions which takes place during the drying of oils. In addition, i t determines the maximum effective concentration of any one particular metal drier (66). This variation of maximum with temperature varies with the metal radical of the siccatives. Iron soaps, for example, appear to have a high temperature coefficient (27). Although important factors, light and moisture are secondary to temperature in the magnitude of their effects. The rate of drying is not affected, however, when pure oxygen is substituted for air (66). Krumbhaar (18, 27) describes how the efficiencies of driers are intensified by the addition of soluble peroxides, but he points out that peroxides themselves have no catalytic properties in the absence of driers. Similar claims have been made for aromatic ketones and aldehydes. The presence of other soluble metal soaps, even if they are not driers, also enhances drier efficiencies, while fatty acids (27, $0) aid in producing more stable solutions of certain driers in oils. The solubility of a drier in the oil or varnish is a factor of primary importance (11,12,47).Purdy, France, and Evans (46) noted that driers in some instances may be colloidally dispersed in the oil. Such dispersions are poorer in their drying properties than the same systems which show a homogeneous field under a microscope. Hence, it is practically impossible to compare the efficiencies of driers at the same effective concentration unless they are completely dissolved in the oil. This was clearly illustrated in the extensive in-
631 ~
TABLE I. EFFEC :TIVENESS OF SICCATIVES UPON THE DRYING OF VARIOUS FILMS Relative Amount Temp. Humiditj % F. % Pale Raw Linseed Oil
Drier A. Go diohlorostearate
0.20 0.02 0.20 0.02 0.20 0.02 0.20 0.02 0.20 0.02 2.5 1.0 2.5 1.0
Co diohlorostearate Go linoleate Co linoleate Co naphthenate Go naphthenate Mn dichlorostearate Mn diohlorostearate Mn naphthenate Mn naphthenate Pb diohlorostearate Pb diohlorostearate Pb naphthenate Pb naphthenate B.
63 63 63 63 63 63 63 63 63 63 63 63 63 63
36 36 36 36 36 36 36 36 36 36 36 36 36 36
3:5
69.5 69.5 69.5
41 41 41
6 9*5 69.5 69.5 69.5 69.5 69.5 69.5 69.5 69.5 69.5 69.5
41 41 41 41 41 41 41 41 41
2:45 5:0 2:45 5:0 2:48 5:0 14: 15 16: 1.5 14: 15 16:15 11:0 15:30 11:0 15:LlO
7:10 3:5
7:10 3:5
7:10 3:40 6:0 3:40 6:0 5:0 7:15 5:0 7: 15
Pale Bodied Linseed Oil
Go dichlorostearate
0.20 0.02 0.20 0.02 0.20 0.02 0.20 0.02 0.20 0.02 2.50 1.00 2.50 1.00
Co diohlorostearate Go linoleate Co linoleate Co naphthenate Co naphthenate Mn dichlorostearate Mn dichlorostearate Mn naphthenate Mn naphthenate Pb diohlorostearate Pb diohlorostearate Pb naphthenate Pb naphthenate C.
Drying Time Hr.:min.
4:
Synthetic Floor Varnish
Go diohlorostearate
2:20 2:35* 2:35e 2:558
Co diohlorostearate" Go dichlorostearate'J Co diohlorostearateo Co dichlorostearateb Co diohlorostearateb C o diohlorostearateb Co dichlorostearateb Co linoleate Co linoleate Co linoleate Co linoleate Co linoleate Co naphthenate Co naphthenatee Go naphthenated Co naphthenatea Co naphthenated Co naphthenateo Co naphthenated >In dichlorostearate 1In dichlorostearate Mn dichlorostearate >In dichlorostearate Mn naphthenate Mn naphthenateo Mn naphthenated Mn naphthenatec Mn naphthenated Mn naphthenatec Mn naphthenated Pb dichloroatearato Pb dichloroatearate Pb dichlorostearate Pb dichlorostearnte Pb dichlorostenrntc Pb naphthenate Pb naphthenatec Pb naphthenated Pb naphthenatec Pb naphthenated Pb naphthenatec Pb naphthenated Pb naphthenate
2:0*
2:0' 2:15. 4:0
63 68 67.5 64 63
0.2 0.06 0.05 0.05 0.02
35 34 35 31 35
2:2!
2:0
2:0e 2:16' 4:0 2:20 2:0' 2:0e 2:0"
2:0*
0.2 0.06 0.05 0.06 0.2 0.06 0.05 0.05 0.05 0.05 0.05
63 68 67.5 64 63 68 68 67.5 67.5 64 64
35 34 35 31 35 34 34 35 35 31 31
2.5 1.8 1.8 1 8 1.8 1.8 1.8 1.0
63 68 68 67.5 67.5 64 64 63
35 34 34 35 35 31 31 35
D . Synthetic &Hour Varnish 0.20 60 0.02
Mn dichlorostearate Mn diohlorostearate Mn naphthenate Mn naphthenate Pb dichlorostearate Pb dichlorostearate Pb naphthenate Ph naphthenate a Green. b Ruby. Fuohs and Lann Droduct.
60
60
0.20 0.02 0.20 0.02 0.20 0.02 0.20 0.02 2.6 1.0 2.5 1.0
60
60 60 70 70 70 70 70 70 70 70 d 8
2:15* 2: 15' 10: 15 3:45* 3:45 3:25' 10:15 3:45* 3:45e 3:45: 3:46 3:20* 3:20@ 10:20 3:20. 3:20' 3:25e 13:0 10:20 3:20* 3:20* 3:20* 3:200 3:25. 3:25* 13:0
26 26 26 26 26 26 40 40 40 40 40 40 40 40
Advance Solvents product. Old varnish.
1:65 3:55 1:55 3:65 1:55 3:55 5: 15 8: 15 5: 15 8:15 3:10 3:25 3: 10 3:25
632
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 33, No. 5
I
2 0:
> 6
0 IL
I-
z Y
@2 0. W
I
2 e > U P
c Z'
V W
P
a W
TIME
FIG
4.
-
HRS.
W A T E R E V O L V E D BY VARNISHES
TIME
-
4,no drier: B, cobalt; C,manganese; D,lead. The floor varnish contained 43 per cent Varnolene, 7.2 mineral spirits. and 0.8 naphtha as thinner: cent Varnolene. 7.2 mineral spirits, and 0.8 naphtha.
vestigations of the Montreal Paint arid Varnish Production Club (34). I n the study described here, liquid driers were used throughout to ensure complete molecular dispersion in all instances. From previous comparisons of drier efficiencies (7, 9, 14, 40, 48), i t might be said that the negative radical usually has no effect upon the catalytic properties of a drier. Curwen's results (10) can be excluded since he undoubtedly did not have true solutions. The negative group, however, is a n important factor in determining the ease with which a complete molecular solution can be obtained (6). The ease of solution in petroleum solvent mixtures was one of the outstanding features of the dichlorostearates described in this paper.
iMaterials Used The dichlorostearate driers used were prepared in the laboratory of the Kational Oil Products Company. When analyzed in the usual manner, the cobalt dichlorostearate contained 0.6 per cent, the manganese soap, 6.0 per cent, and the lead salt, 18.8 per cent. None of these soaps could be easily dissolved in mineral spirits, but complete solution was readily obtained at room temperatures when a mixture of 10 per cent naphtha and 90 per cent mineral spirits was employed. Solutions containing, respectively, as much as 3 per cent cobalt, 3 per cent manganese, and 10 er cent lead were easily prepared with this solvent mixture. 8hese solutions were diluted so as to contain 0.4 per cent cobalt or manganese, or 5 per cent lead before being added to the oils or varnishes. The manganese and lead dichlorostearate solutions showed no change when stored for 14 months, but cobalt
HRS.
F I G . 5. CARBON DIOXIDEEVOLVED BY VARNISHES
the 4-hour varnish contained 50 per
dichlorostearate, both as a solid and in solution, changed in color from ruby red to dark green within 3 weeks. The green drier, probably a complex, was inferior to the ruby one in catalytic properties. Fresh preparations of the cobalt soap were therefore used. The cobalt linoleate, a liquid drier, was donated by the Hilo Varnish Company. It contained 0.4 per cent metal and was used as such. Two sets of liquid naphthenate driers were also used. One set was donated by the Fuchs and Lang Manufacturing Company, and the other by the Advance Solvents and Chemical Corporation. These driers were diluted with the above petroleum solvent mixture to the same concentrations as the dichlorostearates. The commercial liquid driers were used, since no success had been had in preparing suitable solutions from solid naphthenates when attempts were made to dissolve them directly in simple hydrocarbon solvent mixtures. The vehicles used were a raw pale linseed oil, a pale 00 heatbodied linseed oil, a synthetic floor varnish, and a synthetic 4-hour varnish selected by Joseph Mattiello as representative of the vehicles of a wide range of different histories.
Drier Efficiencies The various types of driers were compared first for their ability to accelerate the drying of films of each of these four vehicles. Samples of 50 grams of oil or varnish were used. Comparisons were made a t two concentrations of metal, based on the weight of oil or varnish. Films were flowed on glass plates and then hung vertically to dry after the excess had drained off.
I
May, 1941
.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
A letter W of regular printer's type, weighing 92.0 grams, was used for determining the dry-hard point. The letter mas placed carefully upon the film, allowed to stand for 10 seconds, and then slowly removed. When the film showed no signs of rupture, it was considered to be completely dry for the purpose of these comparisons. This method was far superior to the customary finger technique so frequently used, and can be carried out with equal ease. The end point was detected within 5 minutes for film drying in less than 7 hours and within 15 minutes for all other films. This represented a precision of 3.5 to 4.0 per cent in estimating the drying time. Relative humidities and temperatures were recorded during all measurements. A furnace room proved to be a fairly satisfactory place for carrying out these series of tests. Quintuplicate films were prepared for each test, and duplicate runs were made upon different days. The time required for the various films to dry is summarized in Table I. Since duplicates gave identical results, only one value is recorded for each run. Thus, there were no appreciable differences in the catalytic effect if the driers contained the same metal radical, except in the case of cobalt dichlorostearate which had undergone a color change (Table IC). With manganese and lead driers, the films of the raw oil dried much more rapidly than those of the bodied oil. The reverse was true for the cobalt driers. A difference was also noted in the behavior of manganese and lead driers as compared with those of cobalt in the case of the synthetic floor varnish (Table IC). With this vehicle a marked acceleration in drying time was observed when the manganese and lead driers were added to the varnish after it had been stored for 6 months or more, without the previous addition of siccatives. Age had little effect, if any, when cobalt driers were used. In general, cobalt driers gave the most accelerated drying. Figure 1 shows that the most practical amount of any one metal drier is the Same for all vehicles. These concentration curves were based on data obtained with naphthenate driers, since the dichlorostearates had been shown to give identical results.
Effect of Driers on Oxidation of Oils The naphthenates and dichlorostearates were also compared as to their effect upon the oxidation of the oils. I n this series of tests the cobalt and manganese driers were added in amounts equivalent to 0.02 per cent of the vehicle, and lead driers in amounts equivalent to 1.0 per cent. The procedure used extensively by Rhodes and his co-workers (48-64) was employed for measuring the amount of oxygen absorbed and for noting the increase in weight of the oils during drying. The amounts of volatile matter given off were obtained by difference. It included the 8 per cent of thinner added during the incorporation of the driers. Tables I1 and I11 show that again there was practically no differcnce between the respective dichlorostearate and naphthenate driers, but that the metal radical of the drier had a distinct effect upon the nature of the drying reactions. This series of measurements is also shown graphically in Figures 2 and 3. As others have already observed, cobalt driers promoted the more complete oxidation of oils, while lead siccatives caused gelation to take place a t much lower oxygen contents. The amount of oxygen absorbed by the raw oil in the presence of manganese in this study mas comparable to the amount absorbed when cobalt siccatives were added. The amount of volatiles given off in the presence of manganese driers was, however, considerably less than in the presence of those of cobalt. The lead driers caused the least loss of material. This raw oil had practically a negligible induction period in the presence of any of the driers. The total amount of oxygen absorbed by the h s of
TABLE
Time
Hours
11.
633
EFFECT OF DRIERS UPON THE
PALE LINSEEDOIL
OXIDATIONOF RAW
Net IncreaFe in Wt. of Film A" Bb
Oxygen Absorbed A B Weiaht per cent of oil Cobalt Driers
-
1.5 15,0 6 14 9 ,. 5
4.00
3.95
ll,60 10.73
11,56 10.71
4.41 12,23 16,90 12.58
4.30 11,97 12.67 16,87
73.5 88.5 94.5
11.71 11.81 11.78
11.62 11.75 11.67
17.08 17.68 17.70
16.96
1.5 17.0 25,0 41.5 65.0 70.5 8.8
4.50 9.30 9.90 10.55 10.87 10.85 10.78
4.41 9.47 10.05 10.73 11.09 11.07 11.00
Volatile Evolved A B
5 1 ,. 3 85 0
0.41
0.35 1,65 5 1.96 ,31
17.95 17.97
5.37 5.86 5.92
5.34 6.20 6.30
5.72 13.10 14.00 15.88 17.85 17.95
1.33 3.55 3.90 4.95 6.43 6.55
1.81 3.63 3.95 5.07 6.76 6.88
4.13 9.00 9.52 11.15 11.30
0.98 1.91 2.07 3.15 3.25
0.95 1.82 1.95 3.06 3.20
Manganese Driers 5.83 12.85 13.80 15.50 17.30 17.40
...
...
..
..
Lead Driers 2 14 21 60 71
3.21 7.30 7.68 8.23 8.12
3.18 7.18 7.57 8.09 7.96
4.19 9.21 9.75 11.38 11.50
' Dioh'orostearate*
' Naphthenate'
the bodied Oil was much less than that by those of the raw oil when cobalt or manganese driers were added, but it was nearly equal to that of the raw oil when the lead drier was used. The initial rate Of absorption, however, was slower in all cases with the bodied oil. This is evident from the clearly defined induction Periods with this vehicle. The induction period with the manganese driers was exceedingly long (Figure 3). This may have been due in part to the relatively large amount O f Volatile material evolved during the early Part of the drying when these metal driers Were Present, The curves are Peculiar in shape and show a definite loss in weight by the films during this initial period. This loss was probably due in part to the presence of a small amount of thinner. Surprisingly, these curves indicate that the thinner was retained for much longer periods than was expected. It had been assumed a t firstthat the thinner would have completely evaporated before making the first measurements. A less marked, initial loss in weight of the films was observed with the lead driers. That no such loss was obtained '
TABLE111. EFFECTOF DRIERS UPON THE OXIDATIONOF PALE00 BODIEDLINSEEDOIL Time Hours
Net Increase in Wt. of Film Aa Bb
Oxygen Absorbed A B Weight per cent o f f i l m Cobalt Driers
-
2.0 3.5 18.0 20.0 42.0 49.0
0.60 1.44 5.01 5.02 6.37 6.58
0.61 1.40 5.00 5.58 6.34 6.58
17.0 41.0 49.0 64.0 66.5
-1.57 -1.40 -0.34 i-3.61 3.88
-1.56 -1.39 -0.34 f3.69 3.91
2.0 17.5 25.0 41 . O 48.0
-0.19 4-3.92 5.32 6.41 6.99
-0.19 f3.90 5.29 6.39 6.96
1.58 2.62 7.74 9.10 11.17 11.62
Volatile Evolved A B ~
1.57 2.62 7.72 9.07 11.02 11.60
0.98 1.18 2.73 3.48 4.80 5.04
0.21 0.58 1.83 6.45 6.82
1.79 2.00 2.20 2.83 2.88
0.02 4.60 6.08 7.72 8.94
0.04 0.68 0.76 1.29 2.01
0.96 1.22 2.72 3.49 4.86 5.04
Manganese Driers 0.22
0.60 1.86 6.44 6.76
'
1.77 1.97 2.17 2.86 2.91
Lead Driers
0
Naphthenate.
b
0.03 4.59 6.07 7.68 8.98
Diohlorostearate.
0.02 0.69 0.79 1.32 1.98
INDUSTRIAL AND ENGINEERING CHEMISTRY
634
TABLE IV. EFFECT OF DRIERS UPON THE DECOMPOSITION REACTIONS OF A SYNTHETIC FLOOR VARNISH* Total Loss in Wt. of Films
Time Hours
7
13.0 16.5 20.5 64.5 70.0 88.0 96.0 119.0
4.65 6.55 8.54 12.24 14.48 26.04 28.31 30.59
16.0
24.0 39.5 47.0 119.0
13.5 18.5 63.0 69.0 93.0 141 165
15.0
23.0 39.0 45.5 87.0 111.0
Total Water Evolved Per cent of varnish No Drier 0.85 1.23 1.59 2.00 2.54
Total COZ Evolved
.. ..
..
9 .
A" 4.40 6.80 8.79 9.29 14.89
Cobalt Driers Bb A 4.43 1.30 6.78 2.25 8.81 3.13 9.32 4.16 14.94
A 3.90 7.19 10.87 12.86 25.21 27.99 28.88
Manganese Driers B A B 4.37 1.19 1.22 7.23 1.97 1.98 11.00 2.74 2.77 12.99 3.39 3.42 24.56 27.53 28.50
A 6.38 10.42 13.34 17.36 30.89 31.27
Lead Driers B A 6.30 1.74 10.46 2.90 13.38 3.88 17.49 4.52 33.72 33.98
.. .. ..
B 1.33 2.28
3.16
4.22
..
.. .. ..
B 1.91 2.08 3.85 4.59
....
.. ..
0.48
A 0.14 0.24 0.32 0.35
0.14 0.25 0.33 0.36
..
0.14 0.26
0.35
..
-. ..
A 0.16 0.23 0.30 0.34
B 0.16 0.23 0.30 0.35
.. ..
7
5.58 8.50 11.15 15.33 18.34 34.83 37.21 39.21
I .
.. ..
* Varnish
THE
DECOMPOSITION REAC-
Total Water Evolved Per cent of varnish No Drier 0.88 1.38 1.74 2.00 2.51
Total COS Evolved P
0.05 0 08 0.22 0.38 0.49
......
.... ..
16 21 40 46 63 113
2.80 6.87 10.21 13.26 23.24 28.04
Cobalt Driers Bb A 3.41 1.59 6.82 2.84 10.76 3.89 14.16 4.89 23.85 28.83
2.82 3.90 4.91
0.08 0.13 0.17
0.13 0.18
17 25 41 48 72 96
A 8.36 14.70 18.37 21.22 34.25 36.67
Manganese Driers A B 8.78 2.39 2.42 15.06 3.81 3.89 18.70 4.56 4.62 21.70 5.37 5.44 35.67 37.36
A 0.27 0.36 0.45 0.47
B 0.28 0.38 0.44 0.47
A 7.77 11.98 16.19 20.40 24.14
B 9.14 13.82 17.60 20.85 23.95
AD
B
*. ..
DRIERS UPON
U HOUR SYNTHETIC VARNISH*
Total Loss in Wt. of Films
Time Holzra
B
A 0.15 0.27 0.34 0.44
..
EFFECT OF TIONS OF A
13.0 16.5 20.5 64.5 70.0 88.0 96.0 119.0
0.05 0.09 0.19 0.35 0.42
.. ..
..
.
TABLE V.
Vol. 33, No. 5
15
22 39
46 63
.. ..
B 1.66
.. ..
B
.. ..
Lead Driers A 2.30 3.78 4.62 5.59 6.39
.. ..
B 2.38 3.85 4.66 5.62 6.44
A 0.06
.. ..
*.
*.
A 0.31 0.45 0.56 0.67 0.59
B 0.06
0.09
.. ..
.. .. B
0.30 0.44 0.58 0.58 0.60
* Varnish
qontained 43% Varnolene, 7.2% mineral spirits, and 0.8% naphtha as thinners. a Naphthenstos. b Dichlorostearates.
oontained 50% Varnolene, 7.2% mineral spirits, and 0.8% naphtha as thinner. 0 Naphthenates. b Dichlorostearates.
with cobalt driers or with the raw oil was probably due t o the rapid oxidation of these films. The consequent rapid increase in net weight in these instances masked the effect of the loss of the small amount of thinner added.
sible idea of the comparative effect of different driers upon the nature of the decomposition reactions. Distinct differences were observed with driers of different metals, although the amounts of these reaction products represented but a small percentage of the weight losses incurred, as Tables IV and V show. In every instance, however, the naphthenate and corresponding dichlorostearate driers produced similar quantities of water and carbon dioxide. The amount of organic matter absorbed by the sulfuric acid was small. The two varnishes without driers evolved practically the same amounts of each of these products during drying, although the 4-hour synthetic varnish lost considerably more weight than the other. The synthetic floor varnish lost, for example, 2.53 per cent water and 0.42 per cent carbon di-
Effect upon Decomposition of Varnishes during Drying This effect of thinners was even more marked in the case of the two synthetic varnishes where an additional 40 to 50 per cent of thinner had to be added in the preparation of the vehicles for suitable handling. Films of these materials lost weight throughout the entire drying period. Hence, in this series of experiments the procedure used by 01sen and Ratner (41) was employed, and the amounts of water and carbon dioxide evolved were measured in order to obtain some pos40
sa I
'DSO e4 225 8 Y 0
90
c z w I8 P
,* Y
IO
5
0 TIME
FIG.6,
-
HRS.
LOSS I N WEIGHT BY FLOOR VARNISH
TIME
- HRS.
F I G . 7 . L O S S I N W E I G H T BY 4-HOUR VARNISH
A, no drier; B . cobalt; C,manganese: D . lead. The floor varnish oontained 43 per oent Varnolene. 7.2 mineral spirits, and 0.8 naphtha as thinner: the 4-hour varnish oontained 60 per oent Varnolene. 7.2 mineral spirits, and 0.8 naphtha.
INDUSTRIAL AND ENGINEERING CHEMISTRY
May, 1941
FIG. 8. T Y P E S OF C A TA LY 2 E D C UR V E S
1. 2. 3.
Total solvent loss. Net weight of unthinned varnish film. Composite ourve of 1 and 2.
oxide, and the 4-hour varnish, 2.51 and 0.49 per cent, respectively. Cobalt driers increased the amounts of water evolved with both varnishes but reduced the amount of carbon dioxide with the 4-hour varnish. The amounts evolved for the two varnishes were 4.2 and 4.9 per cent of water, respectively, and 0.44 and 0.18 per cent carbon dioxide. Manganese driers caused a loss of 3.4 and 5.4 per cent water and 0.44 and 0.46 per cent carbon dioxide, while the lead siccatives produced 4.5 and 6.4 per cent water and 0.35 and 0.59 per cent carbon dioxide. The rates a t which these products were formed are shown in Figure 4 and 5. Thus, metal radicals differ in their specific effect upon drying reactions of the two varnishes, and no postulate can be written as yet to cover the precise manner in which driers may take part in these reactions. A similar difference in effect was also noted in the loss in weight during the drying of these varnishes as shown in Figures 6 and 7. As would be expected, they are a composite of curves €or the rate of solvent evaporation and those of the net weight increase due to oxidation. The solvent loss throughout the entire drying exceeded any gain through oxidation. The total loss in weight for the floor varnish in 119 hours without driers, for instance, was 39 per cent of its weight. With cobalt driers, it was 15 per cent, with manganese driers, 29 per cent, and with lead soaps, 32 per cent; while with the 4-hour varnish which dried with a loss of 31 per cent in weight, with cobalt driers a loss of 28 per cent occurred, and with manganese and lead driers, 24 per cent.
Discussion These results show that siccatives with different metal radicals affect the drying reactions of contrasting types of vehicles in varying manners. They suggest that a possible clue to the precise function of driers may be found during a more detailed study of the volatile products evolved under different conditions. The only possible explanation which can be given a t present to account for the widely differing results is that driers form a series of unstable complexes with several of the reactants and intermediate products. This possibility has already been discussed above. Thinners also probably have a marked influence upon the type of complexes formed and, in turn, will materially influence the catalyzed reactions. Some idea of the manner in which these solvents may evaporate from the films during drying can be gained by comparing various theoretical curves
635
with those obtained in this study. This procedure is the only one available in the absence of specific data upon the subject. A series of curves combining those for possible solvent evaporation with net increase in weight during oxidation of the nonvolatile portion are shown in Figures 8 and 9. The first series represent curves for the highly catalyzed type of reactions. Three examples are shown. The first curve illustrates the type which might be obtained when the total loss of solvent is completed a t the same time that the nonvolatile portion would reach its maximum weight in the absence of thinners. Actual examples of this shape of curve are shown in Figure 2 and by the cobalt curves of Figure 3, where the net increase in weight exceeds a t all times the amount of thinner lost, and in Figures 6B, 6D, and 7 0 which are examples of the reverse set of conditions where the thinner loss was continuously in excess. The second theoretical curve is an illustration of the type of graph that might be obtained when the curve for net increase in weight reaches a maximum before the solvent has completely evaporated. Figure 8B is a special case of this type. The same shape is also obtained for the autocatalyzed type of reaction (Figure 9A). Figures 6A, 6C, 7A, and 7B are examples of this type. Figure 8C is typical for instances where a small amount of solvent has completely evaporated before oxidation has reached its maximum in a highly catalyzed reaction. The shape of the curve is similar to one obtained with distinctly autocatalytic reactions (Figure QB).
I
+/
1%
3 / TINE c
F I G . 4. T Y P E S O F AUTOCATALYZED CURVES 1.
2. 3.
Total solvent loss. Net weight of unthinned varnish flu, Composite Curve of 1 and 2.
Figure 9 illustrates the types of curves which might be obtained in the latter instances. I n OA, curve 2 has the same curvature as curve 1, above the point of its inflection, a. When the nonvolatile curve has a larger curvature, graph B i8 obtained; where it has a steeper slope, type C results. The curves obtained when manganese or lead driers were added to the bodied oil are examples of the type of C. Here, the amount of thinner is small. The point where the solvent evaporation curve crosses the gain-in-weight curve (Figure 9C) corresponds to the point where the combined weight curve crosses the abscissa axis. When the experimental graphs for change in weight of t h e films are compared critically with these theoretical curves, it is apparent that the small amount of thinner added to the raw oil probably had little effect upon the results except possibly to increase slightly the slope of these curves. The same was true in the case of the bodied oil with cobalt driers. Comparison of the maxima of the experimental curves seems to show that the bodied oil in all instances probably retained the thinner for much longer periods than the raw oil,
INDUSTRIAL AND ENGINEERING CHEMISTRY
636
This would account for the comparatively large initial period of loss in weight observed when manganese was added to the bodied oil. The more highly catalyzed reaction in the case of the lead driers resulted in a shorter period of loss. It could well be, however, that the solvent was retained in this case as long as it was with manganese siccatives. The inhibited curve for the manganese driers can only be explained, therefore, by assuming that the thinner in this instance gave rise to more stable drier complexes than in other cases. It would appear impossible to ascertain from the varnish curves what type of reactions took place, since the composite curves in Figures 8A and 9A cannot be differentiated from one another. The S-shaped curves, however, in these figures are indicative of a highly catalyzed reaction, as can be seen by comparing Figures BA, 6C, 7A, and 7B with 8B. Hence, it is likely that all of the curves are of the highly catalyzed type, including those where no driers were added. These varnishes were made with reactive resins, and thus it is logical to assume that they would exhibit small induction periods even in the absence of driers. Summary This study has shown that the metal salts of 9,lO-dichlorostearic acid have the properties which are required for the preparation of suitable liquid driers for use in paint and varnish. Some stabilizer will have to be found for the cobalt salt before it can be used commercially, but otherwise these soaps are equal to present commercial driers in their catalytic effects upon different vehicles. They have the marked advantage that they can be easily dissolved in mixtures of petroleum hydrocarbons a t room temperature to give fairly concentrated liquid siccatives. Based upon estimates of the cost of preparing them in small quantities, they can probably be made and sold in large quantities as liquid driers a t a cost which will meet present competition. Cobalt dichlorostearate did not cause any greater darkening of the films than the commercial cobalt linoleate. The naphthenate driers were slightly superior in this one respect. This investigation has also brought to light several new facts regarding the behavior of driers, especially in the presence of thinners, Further studies of the effect of these two important sets of constituents of modern paints and varnishes is contemplated. It has been suggested that driers may form unstable coordinated compounds during the drying of oils and varnishes. Acknowledgment The authors wish t o express their appreciation to the National Oil Products Company, to the Fuchs and Lang Manufacturing Company (division of the General Printing Ink Company), to the Advance Solvents and Chemical Corporation, and to the Hilo Varnish Company for their assistance in supplying the materials for this study. They wish especially to thank Joseph Mattiello for his interest and assistance, and Karl T. Steik for suggesting the investigation. Literature Cited (1) Bhattacharya, R., and Gidvani, B. S., London Shellac Research Bur., Tech. Paper 15, 12 (1938). (2) Bradley, T. F., IND. ENG. CHEhr., 29, 440 (1937). (3) Ibid., 30, 689 (1938). (4) Bradley, T. F., and Johnston, W. B., Ibid., 32, 802 (1940). ( 5 ) Bradley, T. F., and Richardson, D., Ibid., 32, 963 (1940). (6) Bruson, H., and Stein, O., Ibid., 26, 1268 (1934). (7) Clarke, G . L., and Tskentke, H. L., Ibid., 21, 621 (1929). (8) Coffey, S., J . Chem. SOC., 119, 1152, 1408 (1921): 121, 17 (1922).
Vol. 33, No. 5
Currier, A,, and Kagarise, I., IND.ENG.CHEM.,29, 467 (1937). Curwen, M. D., Oil Colour Trades J., 88, 1711 (1935). Elm, A. C., Ibid., 26, 386 (1934). Finnie, W., Am. Paint J.,21, 7 (Nov., 1936). Folkin, S., and Eibner, A., Seifensieder-Ztg., 34, 821 (1907). Gardner, H. A., Drugs, Oils & Paints, 35, 208 (1919). Gardner, W. H., and Bellet, J., unpub. study of cobalt stearate. Gebauer-Fuelnegg, E., and Konopatsch, G., IND. ENQ. CHEM., 23, 163 (1931). (17) Genthe, A,, Z . angew. Chem., 19, 2087 (1906). (18) Hoofte, F. V., U. S. Patent 2,032,554 (March 3, 1936). (19) Ingel, H., J . SOC.Chem. Ind., 32, 639 (1913); 36, 319 (1917). (20) Jacobsen, A. E., and Gardner, W. H., Div. of Paint and Varnish Chem., A. C. S., Boston, Mass., Sept., 1939. Chern. Assoc., 18, 5 (1935). (21) Jordan, L. A., J . Oil COZOUT (22) Kamphauser, K., and Quincke, F., Farben-Ztg., 32, 571 (1926). (23) Kappelmeier, C. P. A., Ibid., 37, 1018, 1077 (1933). (24) Kass, J. P., and Burr, G. O., J . Am. Chem. SOC.,61, 392 (1939). (25) Koohs, Z . angew. Chem., 34, 80 (1911). (26) Kropa, E . L., and Bradley, T . F., IND. ENQ. CHEM.,31, 1512 (1939). (27) Krumbhaar, W., “Chemistry of Synthetic Surface Coatings”, New York, Reinhold Publishing Co., 1937. (28) Long, J. S.,Paint, Oil Chem. Rev., 86, No. 18, 12 (1928). (29) Long, J. S., and McCarter, W. S., IKD.ENG. CHEM., 23, 786 (1931). (30) Long, J. S.,Reinbeck, A. E., and Ball, G. L., Jr.. Ibid., 25, 1086 (1933). (31) Mackey, W. McD., and Ingel, H., J . SOC.Chem. Ind., 36, 319 (1917). (32) Marling, P. E., IND. ENQ.CHEM.,21, 594 (1929). (33) Meinel, K., Fette u. Seifen, 44, 9 (1937). (34) Montreal Paint and Varnish Production Club, Paint, Oil Chem. Rev., 97, No. 23, 76 (1935). (35) Morrell, R. S., J. SOC.Chem. Ind., 34, 105 (1915). (36) Morrell, R . S., and Davis, W. R., Ibid., 55, 237T, 261T, 265T (1936). (37) Morrell, R. S.,and Phillips, E . O., Ibid., 57, 245 (1938). (38) Ibid., 58, 159 (1939). (39) Morrell. R . S., and Phillips, E. O., J . Oil Colour Chem. Assoc., 23, 103 (1940). (40) Nicholson, G., and Holley, C. E., Jr., IND. ENG.CHEM.,30, 114 (1938). (41) Olsen, J. C., and Ratner, Orig. Com. 8th Intern. Congr. A p p l . Chem., 12, 165 (1912). (42) Overholt, J. L., and Elm, A. C., IND.ENQ. CHEM.,32, 1378 (1940). (43) Pallauf, F., Chem. Umschau Fette, ole, Wachse Harze, 32, 97 (1925). (44) Pfeiffer, P., “Organische Molekulverbindunge”, Berlin, Verlaa. v. Ferdinand Enke, 1927. (45) Purdy, J. M., France, W. G., and Evans, W. L., IND.ENG. CHEM.,22, 508 (1930). (46) Quincke, F., and Kamphauser, K., Furbe u. Lack, 1927, 341. (47) Rasquin, H., Farben-Ztg., 30, 2603 (1925). ENQ. (48) Rhodes, F. H., Burr, C. R., and Webster, P. A., IND. CHEM.,16, 960 (1924). (49) Rhodes, F. H., and Chen, K. S., Ibid., 14, 222 (1922). (50) Rhodes, F. H., and Cooper, J. D., Jr., Ibid., 17, 1255 (1925). (51) Rhodes, F. H., and Goldsmith, H. E., Ibid., 18, 566 (1926). (52) Rhodes, F. H., and Ling, T. T., Ibid., 17, 508 (1925). (53) Rhodes, F. H., and Van Wirt, A. E., Ihid., 15, 1135 (1923). (54) Rhodes, F. H., and Wels, C. J., Ibid., 19, 68 (1927). (55) Rogers, W., Jr., and Taylor, H. S., J . Phys. Chem.. 30, 1334 (1926). (56) Scheifele, B., Farben-Ztg., 33, 337 (1928). (57) Scheifele, B., Fettchem. Umschau, 43, 74 (1936). (58) Schreiber, J., Chem. Umschau Fette, ole, Wachse Harte. 34, 6 (1927). (59) Schreiber, J., Kolloid-Z., 46, 337 (1928). (60) Schreiber, J., 2. angew. Chem., 40, 1279 (1927). (61) Schuts, F. C., and Palmer, F. C., IND.ENG. CHEM.,22, 84 (1930). (62) Stephens, H., Ibid., 24, 918 (1932). (63) Taylor, R., and Smull, J., Ibid., 28, 193 (1936). (64) Vincent, H. L., Ibid., 29, 1267 (1937). (65) Wolff, H., Z . angew. Chem., 37, 729 (1924). (66) Wolff, H., 2.deut. Oel U. Fett.-Znd., 44, 631 (1924). (9) (10) (11) (12) (13) (14) (15) (16)
PRESENTED before the Division of Pamt and Varnish Chemistry a t the 100th Meeting of the Ameriaan Chemical Bociety, Detroit, Mich. Based upon part of a thesis submitted by R. E. Waddell in June, 1940,to the Graduate Faoulty of the Polytechnio Inatitute of Brooklyn, in partial fulfillment of the requirement8 for the degree of master of ohemical engineering.
