Document 3JQErjMRzq1JB8gbegj7qRmXJ
K N -7 1 -4
CUROMATE-MOLiB DATE SO LID SOLUTION
E. I. DU PONT DE NEMOURS & COMPANY
256 VANDERPOOL STREET NEWARK, NEW JERSEY
Serial No. KN 71-4
Copy No.
13
NEWARK PLANT PIGMENT COLOR RESEARCH REPORT
CHROMATE-MOLYBDATE SOLID SOLUTION PIGMENTS
Period Covered
JUNE 1969 - JANUARY 1969
FILE 210 DATE* 2 /10/71
NJ 18179
DUP050082581
m 71-4
Copy 13
1* Numerical File
2. Research Office File - 210 3. Newark Library File - 210 4. M.Hunt/E.Gonick, Pigments, Wilmington 5 . W.S.Struve/J.Jackson/A.R.Hanke 6. R.H.Wetzel, Newport (Circ. and File) 7. E.E.Jaffe/E.F.Klenke/B.H.Perkins/Library 8. P.J.Monahan, Newark (Vital Records) 9. N.G.Fisher, Central Research Dept., Wilmington 10. Newark Library - for Central Report Index 11. Newark Library - for Central Report Index
12. fttrinrn 13 Extra 14. Extra 15. Extra 16. Extra 17. Extra
NEWARK PLANT
PIGMENT COLOR RESEARCH REPORT
SUBJECT;
CHROMATE-MOLYBDATE SOLID SOLUTION PIGMENTS
PERIOD COVERED; JUNE 1968 - JANUARY 1969
SUBMITTED BY; APPROVED BY;
< ' J || J. F. HIGGINS
C
. 'j ft
E. F. KLENKE, JR.
Date Submitted: 1/18/71 Date Released: 2/10/71
ABSTRACT:
Solid solutions of Ba, Sr, Ca,. Cu and Zn chromates with molybdate and tungstate ion plus a little sulfate ion were explored. While all had moderate to good activity as primers, none equalled zinc chromate (Y-539-D) No unique color properties were found. The superiority of the solid solutions over mixtures in primer capability was demonstrated.
DUP050082582
HCTRODUCTIOH
Because of the unique color of molybdate orange# the three component solid solution of lead chromate-molybdate and sulfate, it was decided to explore other metal combinations to determine whether other unexpected colors or properties might be obtainable in the barium, strontium, calcium, zinc and copper series, using essentially similar preparation techniques.
The lighter metal chromates alone have a variety of uses: calcium for example in ship-bottom paints, corrosion inhibition defoliation in soybeans and cotton, cement hardening, and as a fungicide; barium as a primer, explosive delay and a craze-inhibitor in plastic sheets; strontium as a primer and explosive delay; zinc as a primer and in tomato blight control; and copper as a tarnish inhibitor, in termite control and as a catalyst. The corresponding molybdates have less utility except for copper molybdate, utilized as a fungicide, wood preservative and to protect against marine borers, and zinc molybdate as a primer pigment.
In order to round out the series it was also planned to substitute tungstate ion for molybdate ion.
SUMMARY AND CONCLUSIONS
The systems indicated in Tables I and II were delineated. Generally speaking solid solution formation occurred, as indicated by x-ray patterns, with relatively small amounts of the larger molybdate and tungstate ions going into the respective chromate lattices and larger amounts of the chromate ion going into the molybdate or tungstate lattices The fifteen areas of composition indicated by the letters A to 0 are the solid solution compositions determined. Usually the x-ray pattern of the solid solution was that of the chromate or molybdate or tungstate but two unique patterns, composition K and Kf were found. Color shifts took place about where the solid solution formation was found. Except for the copper series the shifts were not too great. Since a small amount of sulfate was in the commercial sodium chromate used these are all actually ternary solid solutions as indicated in Table III. Table IV lists the compositions by groups according to decreasing chromate ion content and is a further breakdown of the data in Table I. Table V indicates the results of NC 68-31 (a salt chamber exposure series). None were the equivalent of zinc chromate primer, on close examination. Because of higher solubility the copper series was more effective at lower loading. Table VI contains the results of experiments which showed the superiority of solid solutions over mixtures. Table VII shows the color changes and lightfastness achieved.
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-2-
A1though P and P expressed interest in the Strontium and Calcium series the testing program was cancelled at an early stage* Coil coating primers in a baked system (which we have not tested) was the area of interest for P and F. Additionally the copper series was of interest for marine primer bottom coats
Areas which could be explored are the ternary solid solutions having a higher sulfate or other third ion content*
A patent proposal has been submitted primarily to protect us if sampling outside the company is begun*
A typical preparation is as follows *
Solution I
Strontium nitrate (anhydrous) 78*29 grams was dissolved in 2000 cc* of water and the pH adjusted 6.9 -- 7*0* It was then heated to 180P.
Solution 11
20.74 grams of Ha2Cr04 and 43*01 grams of Na2Mo04 was dissolved in 2000 cc. of water and the pH adjusted 9.8 - 9.9. It was then heated to 180P.
Solution II was introduced through a high speed jet for rapid
mixing as follows:
Volume of
Minutes
Solution II
0 500
3 500 6 500 9 500
12 Str period
Sixty grams of NaCl in 250 cc. H20 was then added and the mixture stirred for ten minutes at 180 ^P. whereupon the pH was adjusted 6*0 with Na2C03 and stirred five minutes.
Then 7.2 g. of Ka2SiOa (19%) in 70 cc. of water was added. After a five minute stir 8.9 grams of Ala(S04)3H20(16-18) in 75 cc. of water was added and after- a five minute stir, 3.4 grams Of Na2C0s was added and then a mixture of 1.8 grams of sulfonated petroleum oils and sulfated castor oil was added. This paragraph describes coatings normally added to molybdate orange pigments for lightfast ness and wettability and need not be added to these compositions.
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--3-- The process for calcium compounds was essentially that of U.S* 2,745,764 and U*S* 2,745,765 wherein nuclei of sodium aluminosilicate are formed to aid the precipitation and the volumes were concentrated for insolubility purposes* Experiments are recorded in N.B* 1899*
DUP050082585
N.B. 1899 Ex p *
3
System BaCr04-Mo04-S04 BaCr04 -Wo04-S04
TABLE I
Per Cent Chromate X-Ray
Si Lattice
A) >85
SaCr04
B)>85
BaCr04
5 S rCr04-Mo04~S04 Mixture
.> SO
Srcro4-Wo04-S04 Mixture
>"55
-
Per Cent Chromate .........Sp
C) <.25
D) <.55
X-Ray Lattice
BaMop4
BaWo04
E) <- 60 F) <55
SrMo04 SrWo04
9
Cacr04-Mo Q4-SO4 6) >85
CaCr04
K) C 40
CaMoOt
CaCr04 -Wo04 --S Q4
Mixture >55
X) < 55
CaWo04
10
CuCr04-Mo04-S04 J)> 85
CuCr04
K) S3 <25 Unique
CuCr04-Wo04-S 04 Mixture
*
L) Ss t 55 CuMo04 M) < 40 CuWo04
11 ZnCr04-Mo04~S04 N) 70-85 Unique 0) < 55 ZnMo04
ZnCr04-Wo04-S04
Too Amorphous to read x-ray
Too' Amorphous to read x-ray
Too Amorph 3US to read x-ray
-
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TABLE II 1. System BaCrCXt - BaWCU - Bs SOa
As a two-coraponent system# it may be represented as follows.
CrC>4 W04
Sx
>85
100
0
Sx + Ss
55
Ss i
0 WO4 100
Si has the lattice of barium chromate while sa has the lattice of barium tungstate*
System BaCrO* - Ba MoO,i - BaSCL.
A ladder series indicates solid solutions at both ends of the range with t 15% BaMo04 dissolving in BaCr04 and t 25% BaCr04 dissolving in Ba M0O4. The system, ignoring the very small amounts of sulfate (2.5 - 0.3 mole percent) may be represented as a two component system as follows.
Si + Ss
$3
85 25
Cr04 M0O4
100 0
Cr04
0
M0O4 100
Color value decreases with increased molybdate content going essentially colorless with greatly improved texture. The Si lattice is 8a chromate while the Ss is that of barium molybdate.
2. System SrCrpA - SrHOQ* - SrSO*
This system shows a marked intensification of color from the weak, greenish yellow of pure SrCrC>4 to a redder shade, approximating the light chrome yellow range.
As a two-component system, it may be represented as follows.
| SrCrQ4
i_________Sj_________________
SO
CrC>4 100
M0O4
0
Sx
Cr04 0 M0O4 100
Srcr04 + Si
cr04 100
WO4
0
55
Jo.
Cr04 0 W04 100
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t a b l e II (Cont'd)
3. System CaCr04~caMo04/W04-CaSQ4
The ladder series for calcium. x-rays indicate the following, reduced to a two component system.
i Sj. ...1,,_...,sa.,j-..,sa......_\_____Sp,___________i
85 40
Cr04 100
Cr04 0
Mo04 0
Mo)4 100
1 CaCrpA + Si
t
............ 55
Cr04 100
WO4
_________ 1
Cr04 0
W04 100
4. System CuCrO*-Mo Oa /WOa -Cu SOa
This system has produced a series of greenish yellow colors. The x-ray patterns in the molybdate ladder are especially interesting in that a unique pattern is found for S3 which is unlike either CuCr04 or CuMo04.
Ml Mi 85
sp
Sp 4* Sa 35
Ml
Cr04 100 M0O4
Cr04 0 M0O4 100
In this series S* has the pattern of CuCr04, S2 of copper molybdate and S3 has a peak not common to either.
This does not occur in the series when tungstate is used.
I CuCr04 + Sj.
|
Si
-----------------------------------gfr-----------------------------
Cr04 100
W04
0
Cr04 0 W04 100
The pattern of Si is that of copper tungstate.
5* System Zn C:r04/Mo Oa AJOa - ZnS04
The zinc chromate/Mo04 series by x-ray indicates the following.
1 zn Cro4 .. 1 Si,; ) Si + sa, j sa
j
85 70 cro4 100
55 M004 100
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TABLE IV
Svs:tein
Composition % Chromate
Ba - Cr04 W0O4 - SO4
Ba cr04-M0O4-SO4
> 85 Cr04
Ca - Cr04 -M0O4-SO4
2.5 SO4
Cu - Cr04 ~Mo 04-SO4
Lattice Metal Chromate
Zn Cr04 M0O4-SO4 Cu Cr04 M0O4--SO4
70 - 85 55 t 5
Unique Metal Molybdate
Ba Cr04 W0O4-SO4 Sr Cr04 W0O4-SO4 Ca Cr4 W0O4-SO4 Zn Cr04 M0O4-SO4
<55
Metal Tungstate Metal Tungstate Metal Tungstate Metal Molybdate
Sr Cr04 M0O4-SO4
<60
Metal Molybdate
Ca Cr04 M0O4-SO4 Cu Cr04 W0O4-SO4
< 40
Metal Molybdate Metal Tungstate
Ba Cr04 M0O4-SO4 Cu CrOi Mo Oa -SO*.
<25
Metal Molybdate Unioue
DUP050082590
Ja b l b Data From NC-68-31 combined With Data of Table I
SW tot NO,a
00026 00027
BaCr04/Mo04 II II
85/15 25/75
00030 " /Wo04 25/75
00034
II
II
95/5
00035
Sr Cr04/Uo0* 55/45
00039
*
/W0O4 60/40
00041
/M0O4 25/75
00042
"
/W0O4 10/90
00044
Cacr04/Mo)4 25/75
00045
CaCro4/Wo04 40/60
00046
CaCr04/Wo04 10/90
00050
CuCr04/M004 55/45
00051
CuCr()4/Mo04 85/15
00052
CuCr04/Mo04 95/5
00053
CuCr04/Mo04 25/75
00055
ZnCr04/Mo04 25/75
00056
znCro4/Mo04 70/30
00057
ZnCr04/Vo04 85/15
00053
ZnCr04/Wo04 55/45
Zinc Yellow Control
TableTM! . Comp .
A c D B E Mixt E F H I I t J : G K 0 N mm -
Hours to Failure
25%
100%
Active>
Active
148
124
148
179
148
179
148 124
148 148
179 179
148
179
124
179
179
179
179
179
179 50 50
179 46 72
179
179
124
46
179
179
179
179
179
50
179
50
179
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SW Lot WO-
TABLE VI
(From NC -69-13 10/14/69)
Active
Composition
Rating (10 - 0)
Table I 179 hours.
Comp
0 Wo Chancre
00077 00049
25% 25%
CuCr04/Mo04 85/15 CuMo04(Cr Molyb)
j -
4 2
00078
25%
CuCr04/Mo04 95/5
j
4
00076
25%
CuCr04
-1
Mixt 85
25%
85% CuCr04 + 15% CuMolyb
-1
Mixt 95
25%
95% CuCr04 * 15% CuMolyb
-1
S
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TABLE VII
Series Ctt Sr Ba Zn Ca
Color Chance in Solid Solution Formation Brown --light brown - green
L.F. None
Very green yellow___red shade yellow
improved
Green shade yellow to red shade
Unproved
To darker greener masstones
Little change
Lighter more intense yellow MT
Little change
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