Drying of Linseed Oil Paint Concentration of Driers
A method has been devised by which it is possible to follow changes in weight of
DOUGLAS G. NICHOLSON mo CHAE. HOLLEY, JR. University of Illinois, Urbana, Ill.
T
HE rate of oxidation of drying oil films has been studied in some detail by several investigators. Many methods of attack have been used in this work; a summary of them was given by Currier and ICagarise (5),in which the following variables were observed: (a) time required to reach a definite temperature using an oilaoaked cloth (9); ( b ) measurement of the volume of oxygen absorbed as a function of time (1-6, 7, S, 11),and (e) weight, plasticity, or hardness changes as a function of time (6, 10, 12). The latter method was used in this study, the gain in weight of a paint film being the measured variable. This investigation is concerned vith the effect of drier concentration upon the weight changes in a film of paint, rather than a film of drying oil. (Preliminary work showed that the oil alone gained weight far more rapidly than did the pigmented oil.) Genthe (7) and subsequent authors (4, 11) pointed out the errors resulting from data which do not take into account the wlatile products of oxidation. It was assurned in this investigation that the volatile products were a constant factor and, for comparative purposes, were irrelemnt. The agreement of the experimental results seems to indicate that this assumption was not without justification.
paint films while out of contact with air. There is a limiting drier concentration above which no further appreciable acceleration of drying is obtained. A high drier concentration produces more rapid initial drying than a low concentration, although the rapidity of weight gain falls off more rapidly when high concentrations are used. In the cases of cobalt naphthenate and cobalt resinate the rate of gain in weight depends upon the concentration of the cation and not upon the anion of the drier material. A film of linseed oil pigmented with titanium dioxide changes in weight much more slowly than does the unpigmented oil (using equal drier concentrations).
A debail of the mechanism controlling the beam and pan releases is given in Figure 2. A system of cog wheels was used to operate the chain, and an extension on the rod holding the rider finger was used to adjust the rider. According to Rogers and Taylor (12) the use of pure oxygen does not, accelerate the drying of linseed oil when the reaction is catalyaed by driers. The use of oxygeii was considered justified, however, because through its use the purity and constancy of the atmosphere in and surrounding the balance Experimental Procedure could be assured. The oxygen was bubbled through concenAPPARATUS.The apparatus consisted of a glass plate trated sulfuric acid, filtered through glass wool, and intro10.1 X 13.7 cm. upon which a film oi paint 0.011 inch duced t,hrough the outer case into the balance a t a rate (ap(0.279 nun.) thick was spread by a “drawing-down” process, proximately 120 cc. per minute) sufficiently rapid to sweep and a balance to which was connected a gas train. The balance out the volatile oxidation nroducts and prevent any inward (Figure 1) of the chain weigh type, was enclosed in a case. so diffusion of air. MATERIALS.The paint fitted that weighings up to used consisted of titanium 1 .lo00grams could be made dioxide ground in body-Q without opening the case. The glass plate used in linseed oil (3.5 pounds of titanium dioxide per galloii the drawing-down process was 0.049 inch (1.245 mm.) of paint). It contained no drier or volatile thinners. thick. Two flat brassstrips The driers used were solid 0.OGOinch (1.524mm.) thick were p l a c e d beyond the cobalt resinate and cobalt naphtlienate containing 2.3 edges of the plate, a few drops of paint were spread and 10.9 per cent cobalt on the plate, and a level m e t a l , respectively. I n order to facilitate the inmetallic strip was drawn c o r p o r a t i o n of the driers over in contact with the into the paint, oleic acid brass strips. Thus there s o l u t i o n s of these subwas a clearance space of stances were added to defi0.011 inchbetweentheguide nite quantities of the paint. strip and the surface of the I n this way the drier was glass plate. The films of uniformly distributed paint so prepared weighed throughout the paint withbetween 2.7 a n d 3.0 grams. F~GIJRE 1. PHOTOGRAPH OF BALANCE AND CA8E out any necessity of heat114
INDUSTRIAL AND ENGINEERING CHEMISTRY
JANUARY, 1938 ~
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TABLE I. RESULTSOF CAROTENE DETERMINATIONS Brand No
1
2 3 4 5 6 7 8 9 10 11 12 13 14
D a t e of Analysis
Size
Carotene .Mg./later
Valencias. California 11/25/35 176 11/25/35 176 12/4/35 176 12/4/35 176 12/11/35 176 12/11/35 176 6/3/36 200 6/3/36 200 6/10/36 220 220 6/10/36 6/18/36 176 6/18/36 176 6/25/36 200 6/25/36 200 Average 14 samples
1.53 1.25 2.18 2.06 2.12 2.51 1.00 0.65 2.74 2.30 1.69 1.41 0.85 0.76 1 65
California-Washington Navels 1 2 3 4
5 6 7 8 7 9 10
11 12 13 8 14 15 16 17 16 18 16 19 20 20 21 22 23 20 24 23 25 26 27 16 28 29 23 30 31 32 20 33 34 32 30 35 36 37 38 39 1 2 13 40 10 11
12/18/35 12/18/35 12/26/35 12/26/35 1/2/36 1/2/36 1/9/36 1/9/36 1/16/36 1/ 16/36 1/22/36 1/22/36 1/29/36 1/29/36 2/5/36 2/5/36 2/11/36 2/11/36 2/19/36 2/19/36 2 / 2 6/ 3 6 2/26/36 3/3/36 3/3/36 3/10/36 3/10/36 3/18/36 3/18/36 3/25/36 3/25/36 4/1/36 4/1/36 4/7/36 4/7/36 4/15/36 4/15/36 4/22/36 4/22/36 4/29/36 4 / 29 / 36 5/6/36 5/6/36 5/13/36 5/13/36 5/20/36 5/20/36 5/27/36 5/27/36 11/24/36 11/24/36 12/1/36 12/1/36 12/8/36 12/8/36 12/15/36 12/15/36 12/22/36 12/22/36 12/29/36 12/29/36 1/5/37 1/5/37 1/12/37 1/12/37 1/ 19/37 1/19/37 1/26/37 1/26/37 Average 68
176 176 150 126 126 176 176 150 150 126 126 176 176 176 150 150 176 176 200 200 220 220 176 176 200 200 220 220 176 176 200 200 216 216 176 176 220 220 200 200 176 176 200 200 220 220 176 176 150 150 176 176 200 200 220 220 252 252 176 176 176 176 200 200 220 220 252 252 samples
0.68 1.21 1.02 1.02 0.32 0.56 1.50 0.33 1.74 1.22 1.02 0.84 0.82 0.66 1.00 1 - . 12 -0.62 0.70 0.75 n 5fi ”.--
1.13 1.31 1 14 1.13 1.54 L70 0.71 0.70 1,5? 1 . 7 ~ 0.67 1.07 0.69 0.77 1.60 1.03 1.46 1.99 0.78 0.43 1.42 1.79 1.92 1.55 2.97 2.96 1.08 0 92 0.24 0.34 0.83 0.67 0 71 0.89
Brand Color No. i d d e d
1 2 3 4 5
7 8 9 10 11 12 13 14 15 16 17 5
18 19 13 20 21 22 23 19 16 24 25 26 2 6 3 3 20
++ +4+ + ++f+ ++ + + ++ ++ + f ++f -
4-
4-
++ +++ +
D a t e of Analysls
Size
Carotene .Mg./liter
Valencias. Florida 3/3/36 200 3/3/36 200 3/10/36 216 3/10/36 216 3/18/36 250 3/18/36 250 3/25/36 200 3/25/36 200 4/1/36 216 4/1/36 216 4/7/36 252 4/7/36 252 4/15/36 200 4/15/36 200 4/22/36 250 4/22/36 250 4/29/36 216 4/29/36 216 5/6/36 200 8/6/36 200 5/13/36 216 5/13/36 216 5/20/36 250 5/20/36 250 5/27/36 200 5/27/36 200 6/3/36 216 6/3/36 216 6/10/36 252 6/10/36 252 6/18/36 200 6/18/36 200 6/25/38 216 6/25/36 216 Arerage 34 samples
0.41 0.70 0.70 0.44 0.50 0.29 0.74 0.67 0.40 0.32 0.25 0 27 0 33 0 25 1.05 0.95 0.18 0 18 0.58 0.80 0.35 0.71 0.95 0.97 0.72 0 . 56 0 30 0.62 0.92 0.76 0.96 0.33 0.48 0.74 0.57
Pineapple Oranges, Florida 1 2 3 4 2 5
+ ++ + +
+
2
+
6 5 3 7 8 9 10 11 12 13 14 15 3 2 4 16
++f
17
18 5 7 19 10 20 21 22
+ + +
-
++-
+ + + +
4-
+ +-
+ +
12/18/33 12/18/35 12/26/35 12/26/35 1/2/36 1/2/36 1/9/36 1/9/36 1/ I 6/3fi 1/16/36 1/29/36 1/29/36 2/5/36 2/5/36 2/11/36 2/11/36 2/19/36 2/19/36 12/8/36 12/8/36 12/22/36 12/22/36 12/29/36 12/29/36 1/5/37 1/5/37 1/12/37 1/12/37 1/19/37 1/19/37 1/26/37 1/26/37 Average 32
176 176 176 17fi I50 150 200 200 176 90 200 200 176 176 200 200 216 216 216 216 288 288 176 17F 200 200 216 216 252 252 288 288 samples
0.58 0 44 0.29 0 37 0 . is 0.16 0.22 0.43 0.15 0.83 0.52 0.3.5 0.15 0.27 0.10 0.05 0 22 0.27 0 28 0.38 0.26 0.25 0 33 0.51 0.39 0.27 0.8G 0.73 0 18 0.27 0.43 0.21 0.34
111
of @-carotene present, and the values given for carotene are for the total carotenoid pigments extracted. The geographical origin of the samples is given together with the packers’ stated size and the date of receipt m d analysis. I n the case of the Florida oranges, the presence or absence of added color as indicated by a stamp on the fruit is noted. S o C a l i f o r n i a o r a n g e s designated “color added” were examined. Although some of the varieties e x a m i n e d showed a possible seasonal trend in carotene content, on the basis of average weekly values, the variations between samples do not permit a n y general conclusions. The average carotenoid pigment content of all samples examined (Table 111) shows a wide variation between the juice of the California and the Florida varieties. Particularly striking is the ratio of almost three to one for the Valencias from the two sources.
TABLE111. AVERAGE VALUES Variety
No. of Samples
Californis Valencias California-Washington navels Florida Valencias Florida pineapple oranges Florida assorted
14 68 34 32 16
Carotene Ma./l
