Solvent Balance of a SolventDiluent Mixture J. K.STEWART, J. B. DORSCH, AND C. B. HOPPER' Anderson Prichard Oil Corporation, Chicago, Ill.
Samples of two mixtures were evaporated 25, 50, and 75 per cent. The rate of evaporation of butyl acetate in terms of itself showed the least variation. The toluene-Troluoil mixture apparently evaporated a t a greater rate than toluene alone in such solvent diluent mixtures. Based on the assumption that each ingredient would evaporate from the mixture a t the relative rate of evaporation of that ingredient alone, the compositions of the samples were calculated. Fair agreement between the found and calculated values was obtained except for Troluoil. Upon evaporation, the mixture containing
Troluoil developed increasing tolerance a t a more uniform rate than in the case of the mixture containing only toluene as the diluent. The former also showed correspondingly greater tolerance than the latter. The effect of replacing part of the nitrocellulose with resins was observed by means of dilution ratio, resistance t o blush, and viscosity data. The presence of resins appeared to lower the dilution ratio for the mixture containing Troluoil. However, as evaporation progressed, the dilution ratio of this mixture became greater than that of the mixture containing toluene alone as the diluent.
B
consisted of a tin funnel. It was constructed so that its wide end would fit snugly over a 12-inch fan of 110-volt a. c. type. The diameter of the wide end was 34.3 cm. (13.5 inches). The diameter of the narrow end was 23 cm. (9 inches). As a check on the method of evaporation, liter portions of the same sample were subjected to different conditions. One portion was evaporated to one-fourth of its original volume in a 2-liter beaker by means of a draft of air. One portion was evaporated from a shallow tin pan, 43.5 X 28.2 x 2.1 cm. (171/s X 1l1/s X '/8 inch), to one-fourth of its original volume in quiet air. Comparative dilution values of the evaporated samples were 15.6 and 15.3 cc., respectively. During the evaporation, temperature conditions were kept within relatively narrow limits. The initial temperature of the samples was kept between 19.4' and 20.5" C. (67" and 69' F.). Room temperature was maintained between 20.5' and 26" C. (69'and 79" F.).
ROWN and Crawford ( 3 ) pointed out the well-known
need of solvent balance during the evaporation of a lacquer thinner from the film. Bent and Wik (1) suggested the relative rates of evaporation of the thinner ingredients as a handy tool for estimating solvent balance. The purpose of the present paper is to carry this thought a step further by the experimental study of two mixtures of thinner ingredients. The solvents used were prepared from commercial grades by redistillation. The toluene was of A. C . S. grade. The mixtures, therefore, are not strictly comparable to those found in the lacquer industry. Mixture A was composed of butyl acetate, butyl alcohol, and toluene. Mixture B was composed of butyl acetate, butyl alcohol, toluene, and a petroleum diluent. Mixture B bore a simple relation to mixture A. When both mixtures were used to make nitrocellulose solutions, the latter were found to be similar in three respects. The solutions were equivalent as to nitrocellulose concentration, viscosity, and dilution ratio. The evaporation rates were roughly similar. The object of this paper was to prepare samples of mixtures A and B which had been partially evaporated and to study them. Liter samples were prepared by removing 25,50, and 75 per cent of the mixture by evaporation.
Evaporation of Mixtures A beaker of 4-liter capacity with an inside diameter of 15.2 cm. (6 inches) was used as the container. The beaker was placed 7.6 cm. (3 inches) from a w i n d t u n n e l and centered. The wind tunnel 1 Present address, Bradley & Vrooman Company, Chicago, Ill.
Composition
The samples were analyzed-by an adaDtion of the method of Watts (6). I n the case of simple mixtures the method could be simplified both as to p r o c e d u r e and calculations. The substitution of sulfuric acid of 80 per cent strength by weight (specific g r a v i t y 1.727 a t 20" C.) for sulfuric acid of 80 per cent strength by v o l u m e , apparently improved the procedure. The composition of the samples is indicated in T a b l e I. The change of c o m p o s i t i o n in terms of unevaporated sample is shown in F i g u r e 1 f o r FIGURE 1. CHANGE O F COMPOSITION IN TERMS O F UNsamples 1 to 4, and 9 to 12. EVAPORATED SAMPLE FOR SAMPLES 1 TO 4 AND 9 TO 12 899
INDUSTRIAL AND ENGINEERING CHEMISTRY
900 r
TABLEI. COMPOSITION O F MIXTURES % Remaining Sample Hydrocarbons .Butyl Acetatea Butyl Alcohol after Evapn.
-Per
No. 1
100 75 49.72 25 100 75 50 25
2 3 4 6 5 7 8
PO0 75 47.48 25
9 10 12 11
100
13
cent by volume-----
Mixture A 60.2 45 14 .. 05 12.55 5 64 0.5 41.4 12.6 Mixture B 55.0b 45.25 27.15 8.0
29.56 35.14 44.11 59.90 35.80 30.26 44.16 60.82
10.3 10.36 14.89 27.55 9 . 274 14.44 26.58
33.23 39.23 50.21 62.46
11.77 15.52 21.79 30.39
55. O b 33.37 42 59 .. 5 39.28 9 49.50 8.45 63.13 urity Troluoil in the ratio of 20 to 35.
75 14 15 49.25 25 16 a Butyl acetate of 9 4 . 5 7 li A mixture of toluene
VOL. 29, NO. 8
Relative evaporation curves were plotted from data obtained by the Rubek-Dah1 method as shown in Figure 2a (5). The relative rates as calculated are shown in Table 111. Although not strictly Comparable, the rates of Bent and Wik (1) are shown. Figure 2b indicates approximately the relative evaporation curves of mixtures A and B. Calculations were made to check the hypothesis of Bent and Wik (1). The data of Table I were used to calculate the amounts of each ingredient in the sample when 25 per cent of each mixture remained unevaporated. An example based on sample 4 follows: According to Table I, 29.5 cc. of butyl acetate were found in
100 cc. of the original mixture (sample 1). When sample 1had evaporated t o one-fourth of its volume or t o 25 cc., only 59.9 per cent or 15 cc. of butyl acetate remained. Therefore the differ-
11.63 15.22 20.6 28.43
ence between the values represents the volume of butyl acetate that evaporated.
TABLE11. RELATIVE EVAPORATION OF EACH INGREDIENT BASEDON ITS ORIGINAL VOLUME %,Remaining
Sample No.
100
1
%
Hydrocarbons Sample
so
2 3 4
100 67.9 34.2 5.2
100 75 50
9 10 11 12
100 61.8 25.5 3.3
76
25
26
NO.
%
Av. %
Sample NO.
5 6 7
8
100 67.6 34.2 5.2
100 67.8 34.2 5.2
1 2 3 4
13 14 15 16
100 61.9 27.1 3.8
100 61.9 26.3 3.6
9 10 11 12
%
But 1 Acetate Jample
No.
Mixture A 100 5 89.2 6 74.7 7 50.8 8 Mixture B 100 13 88.5 14 75.4 15 46.9 16
When one-fourth of the original mixtures remained, the followingchanges were indicated: Butyl acetatehad roughly doubled. Butyl alcohol had roughly increased two and a half times. Hydrocarbons, however, had decreased to one-fifth or less. The change in each ingredient is clearly shown in Table 11, where the following indications may also be noted:
%
Sample
Av. %
%
5%
-
Butyl Alcohol Sample
NO.
%
Av. %
100 88.6 72.7 50.2
100
88.9 73.7 50.5
1 2 3 4
100 75.4 72.3 68.8
5 6 7 8
100 78.8 78.2 71.9
100 77.1 75.3 70.4
100 88.3 74.2 47.3
100 88.4 74.8 47.1
9 10 11 12
100 98.9 92.7 64.6
13 14 15 16
100 98.1 88.5 61.6
100 98.5 90.6 62.5
This was 29.5 - 15 cc. = 14.5 cc. The fraction of butyl acetate lost then was 14.5/29.5. Therefore, if the evaporation rates of butyl acetate and toluene were the same, the amount of toluene lost would be the initial amount of toluene (60.2 cc.) multiplied by the fraction 14.5/29.5. However, according t o Table 111the evaporation rate of toluene is double that of butyl acetate. Then ~
~
~
~
~
t
be60.2 - 5 9 . 2 ~ = ~ .1 . 0 ~ ~(Found, . 3.1 cc.; calculated, 1.Occ.)
1. The rate of evaporation of butyl acetate, in terms of itself, The data are shown in Table IV. Although not strictly shows the least variation. This lends support t o the idea of using the rates of Bent and Wik were used in a the eva oration of butyl acetate as a reference standard (1). check series. The data indicate a fair agreement between 2. toluene-Troluoil mixture apparently evaporates at a calculated and found values with one exception. Apparently greater rate than toluene alone. The greatest divergence app a r s when the original mixtures are half evaporated. roluoil is a petroleum diluent refined from a Midcontinent crude oil. The estimated composition is TABLEIv. AMOUNTO F INGREDIENT WHEN 25 PER CENT O F A 1oo-cC. roughly as follomqj: paraffins 58 per cent, naphSAMPLE IS EVAPORATED (BASEDON Loss OF BUTYLACETATE) thenes 39, and aromatics 3. The distillation range of a typical sample, according t o the A. S. T. M. -Butyl Alcohol Cc --Toluene Cc Troluoil5 Cc.-Sample No. Found Ca1cd.b da1cd.c Found Calcd,’b Ca1od.c Found Crt1cd.b Ca1cd.C method, is 93.3’ t o 121.7’ C. (dry point). 3. Five per cent or less of the hydrocarbonsre4 mixture^) 6.9 7.3 8.1 3 . 1 -4.7 2.2 ... 12 (mixture B) 7.6 8.2 9.1 0.8 -3.3 -0.8 1 . 0 -i4:3 -is:1 main whenonly 25 per cent of the original mixtures are left. a From unpublished report of Dorsch.
de
--
-
a Using rates from Figure 2a and Table 111.
Evaporation
Using rates published by Bent and Wik ( 1 ) .
According to Bent and Wik (I), “The absolute rates qf evaporation of solvents and diluents usually change somewhat when these materials are added to lacquer mixtures, but the relative rates . . . , are preserved during the evaporation unless the materials form constantevaporating mixtures.” TABLE 111. RELATIVE RATESOF EVAPORATION BASEDON BUTYL ACETATE” 1 2 3b Butyl aoetatea 1.0 1.0 1.0 Toluened 2.21 2.18 2.19 Butyl alcohola 0.58 0.58 Troluoil 2.71 2:63 2.67 Usual temperature of evaporation, 21’ * 1’ C. b Averages. 0 Rates of Bent and,Wik based on commeroial grades. d Redistilled to a boiling range of 1” C. e A. C. S. grade. (I
40 1.0 1.96 0.44 2.88
Troluoil does not follow the general rule. I n this connection it should be pointed out that Troluoil is a mixture of petroleum hydrocarbons.
Tolerance As pointed out by Brown and Bogin (S),the limit of tolerance of a mixture for a nonsolvent has been described as dilution ratio. Therefore, dilution ratios, with respect to Troluoil, were determined for each sample at various concentrations of nitrocellulose. Gasdner points out that “the end points . . . are rather indefinite, and experience is necessary t o be able to check the results” (4). An unpublished report of Daley, Johnson, and Wray discussed end points for mixtures A and B. Ac-
.
~
AUGUST, 1937
INDUSTRIAL AND ENGINEERING CHEMISTRY
901
FIGURE 3. DEGREEOF PRECISION OF DILUTION
FIGURE 2. RELATIVE EVAPORATION CURVES b.
By Rubek-Dah1 Method (5)
Q.
As calculated
RATIOS
w
RATIOCURVES FIGURE 4. AVERAGEDILUTION cording to them, the end point shall be taken when a film of the solution on the sides of the Erlenmeyer Aask appears striated, like the waves of sand a t the seashore. I n very concentrated solutions the striation may give way to a pebbly effect. The degree of precision is indicated in Table V and Figure 3. Figure 4 shows average dilution ratio curves. As pointed out by Gardner, the curves may be considered as straight lines (4).
FIGURE 6. VISCOSITY FIGURE5. RELATIVE TOLERANCEDATAFOR MIXTURES A OF MIXTURES A AND B AND B
TABLEV. DILUTION RATIOVALUES FROM Tnn CURVES % Sample No.
1 2 3
4 9 10
11 6 7 8 14 15 I6
Thinner Remaining 100 75 50 25 100 75 50 75 50 25 75 50
26
-OperatorA 3.9 5.45 0.86
410 6.4 5170 8.62 1.31
.. ..
..
B 4.1
... ...
1.35
C
...
5.60 0.88 ,..
4.0 6:35 0.975 5.67 8.78 1.37 6.45 9.50 1.44
0 : 963
...
... ...
5.84 9.70 1.46
Average 4.0 5.52 0.87
...
4.0 6.38 0.969 5.69 8.70 1.34 6.14 9.60 1.45
%.
Variation 12.5 -1.5
11.1
...
FIGURE 7. CURVES FOR VARYINGCONCENTRATIONS OF SOLIDS WITH
...
10.5 10.6 10.3 *0.9 12
15 *l 10.7
DILUTIONRATIOS OF THINNERS A AND B. As pointed out by Brown and Bogin in 1927 ( d ) , the concentrations of nitrocellulose in the samples a t the conclusion of the dilution ratio determination should be roughly the same. A concentration of 8 per cent was suggested by them ciince it was often found in practice. The concentration waa apparently defined as 8 grams of nitrocellulose to 100 cc. of the final liquid mixture. The concentration used in this paper differs slightly. It may be defined as 8 grams of nitrocellulose in 100 cc. of the solution found a t the end of the determination. This is equivalent t o 0.586 pound of nitrocellulose in a gallon of the final solution.
ESTERGUM
For the calculation of this factor the following bulking values of Hook (unpublished) were used: In mixture A, 1 pound nitrocellulose bulks 0.0739 gallon; in mixture B, 1 pound nitrocellulose bulks 0.0735 gallon. Figure 4 shows the average dilution ratios for all samples, and the following indications may be pointed out: Mixtures A and B match as formulated. At various stages of evaporation, mixture B has greater tolerance than the corresponding sample of mixture A. 3. Considering only the artly evaporated samples, the following point was noted: The xilution ratios for mixture B samples are less sensitive t o changes in the nitrocellulose concentrations 1.
2.
than the dilution ratios for mixture A samples. 4. The slope of the dilution ratio curve for mixture B remains practically the same ap arently until three-fourths of the mixture has been evaporate: 5. In the case of mixture A, the sample 50 per cent evaporated is apparently more sensitive to changes in the nitrocellulose concentration than are the others.
902
INDUSTRIAL AWD ENGINEERING CHEMISTRY
VOL. 29, NO. 8
FIGURE 9. CURVESFOR VARYING CONCENTRATIOXS OF SOLIDS WITH
DAMMAR
This is equivalent to 0.5 pound of nitrocellulose per gallon of solvent mixture and also equivalent to 0.44 pound of nitrocellulose per gallon of nitrocellulose solution. The partially evaporated samples were made up to contain an increased amount of nitrocellulose. The increase in concentration was made to correspond to the increase in concentration that the original solution might have on evaporation. The samples were tested in a Stormer viscometer. The data obtained are shown in Table VI; that mixtures A and B are alike is indicated by Figure 6.
FIGURE 8. CURVESFOR A CONSTANT CONCENTRATION OF SOLIDS WITH ESTER GUM Solids concentration was the equivalent of SO grams per liter of solution.
Figure 5 shows the relative tolerance of mixtures A and B during evaporation, at a constant nitrocellulose concentration. Figure 5 also shows the relative tolerance when the nitrocellulose concentration is increased to correResistance t o Blush a n d Flow spond to that found on evaporating the The samples were submitted to exequivalent original nitrocellulose solucessively critical conditions of humidity tion. The curves indicated that mixand temperature in order t o deterture B has greater tolerance than mixFIGURE 10. CURVESFOR A CONSTANT mine whether a difference in the resistture A . OF CONCENTRATIO N SOLIDSWITH ance to blush could be observed under DAMNAR EXAMPLE. To determine the nitroany conditions. Samples in pairs were Solids concentration was the equivalent of 80 cellulose concentration when 50 Der cent grams per liter of solution. flowed out side by side on glass plates of the liquid mixture has been evaporated. and placed in a humidity cabinet.- The One gallon of nitrocellulose solution contains 0.043gallon of nitrocellulose. Therefore 1 gallon of nitrodata are shown in Table VII. I n all cases where blushing could cellulose solution contains 0.957 gallon of liquid mixture. Therebe observed, the resistance to blush was greater for mixture B fore when 50 per cent of the mixture has evaporated, only 0.4785 samples. No difference in flow was observed. gallon of mixture remains. Therefore at the 50 per cent point, nitrocellulose is 0.043gallon and liquid mixture is 0.4785 gallon. Therefore the total solution at the 50 per cent point is 0.522 gallon, but the nitrocellulose content is 0.586 pound. Therefore TABLE VII. RESISTANCE TO BLUSHAT 90" F. (32.2' C.) AND the concentration of nitrocellulose is 0.586/0.522 = 1.121 pounds 68 PERCENTRELATIVE HUMIDITY per gallon of solution. Apparently the curve for mixture B more closely approaches a straight line than the curve for mixture A. I n other words, on evaporation the tolerance of mixture B apparently increases more uniformly than the tolerance of mixture A.
Viscosity Solutions of the original mixtures were made up so as to contain 6 grams of nitrocellulose per 100 cc. of liquid mixture. TABLE VI. AVERAGEVISCOSITY AT 20' Liquid --Mixture Mixture Sample Remaining" No.
%
AViscosity Centipoises 28.1 47.9 147.2
100 1 75 2 49.72 3 47.48 .. .... 25 4 2040.0 100 .. .... 75 6 50.8 50 7 153.4 49.25 .. 25 8 i85i:~ Maximum variation is *0.5'%,
-Mixture Sample No.
9 10
* 0.2'
C.
B-
Nitrocellulose/100 Cc. Viscosity Solvent Centipoises Grams 27.1 6 51.4 8 12 147.7 12 1830.0 24 I...
ii 12 .. ..
14 l5 16
.... 50.0 ....
145.9 1765.0
..
8
12 12 24
Liquid ---Mixture Mixtye Sample Remaining No.
A-
Blush
B-
----Mixture Sample NO.
Blush
9 10
Very slight Very slight
11
Very slight Very slight
% 100
75 49.72 49.4s 25 100 75 60
49.25 25
1 2 3
Slight Slight Slight
4
slight
..
..6 7
Slight Medium
8
None
..
12
..
......
...... ......
14
None
i6
Slight None
16
Effect of Natural Resins on Nitrocellulose Solutions of Mixtures TOLERANCE. The procedure previously described was used. According to Daley, Johnson, and Wray (unpublished report), the end point is more difficult to check than in the case of solutions containing only nitrocellulose. Therefore the precision obtained for curves is less than for nitrocellulose solutions. Further work along this line would be advantageous. In addition, the curves are drawn through points relatively close together. Therefore considerable error could creep in with regard to the slope of the curves. Figure 7 shows the
AUGUST, 1937
INDUSTRIAL AND ENGI NEERING CHEMISTRY
903
5, with the exception of the intersection of the curves found on the former. Comparison of the two figures indicates that the type of curve is the same. Figures 9 and 10 correspond to 7 and 8, respectively. In the case of the former, the resin used was dammar instead of ester gum. Comparison of Figures 5 and 10 indicates that the relative position of mixture B curves has changed with respect to those of mixture A. This results in a n intersection of the curves roughly a t the stage where 75 per cent of the mixtures remains unevaporated. VISCOSITY. The viscosities of samples 1, 2, 9, 10, 6, and 14 were so low and apparently comparable that they were not determined. The data obtained are shown in Table VIII. TABLE VIII. EFFECTOF NATURAL RESINSON AVERAGE VISCOSITY AT 20" * 0.02" C . NitroLiquid --Mixture A&---Mixture BQ--cellulose/ Mixture Sample Sample 100 c o . Remaining No. Viscosity No. Viscosity Solvent % Centipoises Centipoises Grams Ester Gum 49.72 3X 12 6 3 47 48 . iix li:7 3 25 4x 34 7 12x 33.3 6
Resin/ 100 c c . Solvent Grams 9 9 18
Dammar 49.72 47.48 25
3X
12.5
4x
33:6
..
iix
12x
1i:9 34.0
3 3 6
9 9 18
a Mixtures A and B samples were made up according to composition shown in Table I . These were designated as X samples.
RESISTANCE TO BLUSH. The samples were handled similarly to those containing nitrocellulose as the only solid. The data are shown in Table IX. I n all cases where blushing could be observed, the resistance to blush was greater for mixture B samples. TABLEIX. EFFECTOF RESINS ON RESISTANCE TO BLUSHAT 90" F. (32.2' C.) and 68 PER CENTRELATIVE HUMIDITY Liquid ----Mixture AMixture Sample Remaining Blush - No.
-Mixture Sample No.
BBlush
%
100 75 49.72 47.48 25
1X 2X 3X
Slight Slight Slight
4X
Very'slight
100 75 49.72 47.48 25
1X 2X 3X
...
...
4X
Ester Gum 9X None 1OX None
lix
12X Dammar Very slight 9X Very slight 1OX Slight llx Very'slight 12X
....
None None None None
Very'Alight None
NitrocelluIP&. Solvent Grams
Resin/ 100 co. Solvent Grams
1.5 2 3 3 6
4.5 6 9 9 18
1.5 2 3 3 6
4.5 6 9 9 18
Effect of Synthetic Resins on Nitrocellulose Solutions of Mixtures The procedure previously outlined was used. The following typical resins of the lacquer type were chosen: FIGURE 11. RELATIVETOLERANCE OF MIXTURES WITH SYNTHETIC RESINS Solids concentration was the equivalent of 80 grams per liter of solution.
average curves of the samples for varying concentrations of solids with ester gum as the resin. Figure 8 shows the curves for a constant solid concentration and for a solid concentration that would correspond to that of a n original sample after partial evaporation. Figure 8 therefore corresponds to Figure
R1. Saturated alkyd, soluble in aromatic hydrocarbons and esters, insoluble in aliphatic hydrocarbons and alcohols. R,. Modified phenolic, soluble in hydrocarbons and esters, insoluble in alcohols. R4. Modified alkyd, soluble in hydrocarbons and esters, insoluble in alcohols. Rs.Concentrated phenolic, soluble in hydrocarbons and esters, insoluble in alcohols. Re. Saturated alkyd, soluble in aromatic hydrocarbons and esters, insoluble in aliphatic hydrocarbons and alcohols. R,. Ester gum. RB. Dammar.
INDUSTRIAL AND ENGINEERING CHEMISTRY
904
TABLE X. EFFECT OF SYNTHETIC RESINSON AVERAGE VISCOSITY AT 20' * 0.2" c.
--
NitroMixture B celluLiquid Sample mixture Sample l%&. No. Viscosity remaining No. Viscosity Solvent Centipoises Centipoises Grams 47 48 1lX 15 4 3 3X 16 0 12.4 12 9 3 13.8 14 7 3 12 7 13 0 3 24 6 24 2 3 12.6 12 7 3 12 5 12 9 3
Mixture A-
7 -
Liquid mixtuFe remalnlng
% 49 72
Resin/ 1OOCc. Resin Solvent No. Grams 9 9 9 9 9 9 9
Ri Rs RI Rs Ra R7 Rs
25
their evaporation. Resin R1 apparently is not compatible wit8hmixtures A and B. As the evaporated mixtures grow richer, R1 becomes compatible. RESISTANCE TO BLUSHAND FLOW.The data of Table X I indicate that mixture B has greater resistance to blush a t all stages of evaporation than mixture A. No difference in flow was observed.
Acknowledgment Grateful acknowledgment is due some of the leading lacquer chemists for helpful suggestions. The authors are glad to acknowledge the assistance of G. C. Hook in the preparation of blush test panels. In addition, various members of this laboratory rendered valuable help and assistance in the work. ~~
A--
-Mixture Sample No.
Blush
B-Blush
%
..
1X
100 100 200
1X 1X 1X
100 100 75
IX 1X
2X
75 75 75 75 75 75
2X 2X 2X 2X 2X 2X
slight' Slight Not dissolved Slight Slight Slight Slight Slight Very slight
49.72 47.48 49.72
3X
Slight
3X
Slight'
,
...
...
...
Not dissolved Heavy Medium Medium
9X 9X 9X 9X
QX 9X 1OX 1OX 1OX 1OX 1OX 1OX 1OX
iix .
I
Not dissolved Medium Slight Slight
....
None None Not dissolved Very sljght Very slight None Very slight None None None
.... ....
Nitrocellulose/ 100 Cc. Solvent Grams 1.5
Resin/ 100 Cc. Resin Solvent No. Grams 4.5 R,
1.5 1.5 1.5
4.5 4.5 4.5
1.5 1.5 2
4.5 4.5 6
R, Rs RI
2 2 2 2 2 2
6 6 6
6 6
RS R4 Rs Ra R7 RK
3 3 3
9 9 9
Ri Ri Ra
. . . . . .
6
Rs R4 Rs
Rs
TOLERANCE. The procedure as previously described was used. The results are indicated on Figure 11. Apparently the resins gave the same type of curve. They differed as to the values for the original samples. Consequently the curves differ as to the point of intersection. The slopes of the curves lack the degree of precision that was obtained for curves of nitrocellulose solutions. Indications are that many resins that are less compatible in nitrocellulose solution B than in solution A may become more soluble as evaporation progresses. An exception is 'noted in the curves of Figure l l c . VISCoSITY* The data point to the following: When a resin is soluble in nitrocellulose solutions of mixtures A and B, the solutions remain roughly comparable throughout f'
Liquid Mixture -Mixture Remain- Sample ing No.
~
c.)AND 68 PERCENTRELATIVEHUMIDITY
TABLEXI. EFFECTOF SYNTHETIC RESINSON RESISTANCE TO BLUSHAT 90' F. (32.2' Liquid Mixture ---Mixture Repain- Sample ing No.
VOL. 29, NO. 8
A-Blush
-Mixture Sample No.
B-Blush
% 47.48 49.72 47.48 49.72 47.48 49.72 47.48 49.72 47.48 49.72 47.48 25 25 25 25 25 25 25
3k ... 3X ...
Slight' Gumblush
11X
Very alight
iix
Very'alight
IIX
Gum'biush
lix
None
3X
Slight'
3X
Slight'
... .,.
Slight
llx ..
4X 4X 4X 4X 4X 4X 4X
Slight Gum blush Slight Gum blush Slight Very slight Veryslight
12X 12X 12X 12X 12X 12X 12X
...
...
....
....
..
....
.... None ....
None
None Gum blush None Gum blush None None None
Nitrocellulose/ 100 Cc. Solvent Grams 3 3 3 3 3 3 3 3 3
3 3
6 6
6 6 6
6 6
Resin/ 100 Co. Resin Solvent N o
Gams 9 9 9 9 9 9 9 9 9 9 9 18 18 18 18 18 18 18
Ri R4 Re Rts R.5
RJ Ra Rr Rr Ra Rr
R;
Ra R4
RJ Ro
R7 Ra
Literature Cited (1) Bent, F. A., and Wik, S. N., IND.ENO.CHEM.,28,312-16 (1936).
tg;
: g;;,","dd :A$;:;9,$yg:,?%
~~r~~~~~.Nitroceliu Lacquer," 1st ed., p. 16, New York, Chemical Catalog C o , , 1928. (4) Gardner, H. A., "Physical and Chemical Examination of Painta, Varnishes, Lacquers and Colors," 8th ed., pp. 1087-90, Washington, Inst. of Paint and Varnish Research, 1937. (5) Rubek, D. D., and Dahl, G. W., IND. ENQ.CHEM.,Anal. Ed., 6, 421-2 (1934). (6) Watts, C. E., Ibid., 6 , 262-5 (1934). RECEIVED April 17, 1937. Presented before the Division of Paint and VarChemical Society, nish Chemistry at the 93rd Meeting of the Chapel Hill, N. c., April 12 to 15, 1937.
