Document NgobbpBrQ4oM9dm7rZ54ppaE

E. I. DU PONT DE NEMOURS & COMPANY KREBS PIGMENTS DEPARTMENT 256 YANDERPOOL STREET NEWARK. NEW JERSEY Serial No. KK-48-1 Copy No. 1 0*\ ' NEWARK PLANT PIGMENT COLOR RESEARCH REPORT CHROME GREENS STRENGTH IMPROVEMENT - 550" LINE LABORATORY STUDY Period Covered: May 1947 * Jan 1948 FILE: DATE: 2/12/48 N42151 Serial No. KH-48-1 Copy No* 1 Copy to* #1 - Numerical Tile S - Research Office (214) 3 - Library File (214) 4 - #10 Bldg* File 5 Siegel/J Jaokeon/R.R. Denelov/Library 6 Xsqporial Cheatcal Industries, Ltd* ,, t * 8, * ** $ V* y. Bpengemen 10 - #5 *b. NEWARK PLANT PIGMENT COLOR RESEARCH REPORT Progress Report Titlei Chrome Creese Strength Improvement * *$$Q* Line laboratory Study Period Covered! Kay 194? - Jan. 1948 Charge! AX * C - 4 (1100-11-4) DUP050066838 imMil** ft This will summarise til* experimental work carried out in the laboratory daring -the latter part of 19*7 with ths object of developing blue tint green* stronger than oar present *550* line* Recent sables of competitive greene, notably Imperial's "Vale Oreena" are definitely etronger than ear product*. As a specific example, C$50256 (Imperial A-4442) blended with blue to approximately equal meatone depth was read as t s yellow, slightly dull in bu s stone vs 0-55Q-D and strong and slightly yellow in tint. (100 parts C# plus blus was slightly strong vs 115 parti Q-5J&HD, Referonce |l263-68) the yellowness of tint was noteh less than that of Oar *604* line and attempts to iaprove tinting strength by adding the latter were unsuccessful. Sons years ago, ws had a line of strong bluo tint gresns (0-503-D, 0-504*0, ete.) which are now obsolete. Retained saaplss wars examined but were found to be very eltv*| obviously, they had flopped on storage. Old exhibits indioats that their strength advantage would probably be insufficient to Meteh the present competitive products* Current production of the *550* line has run strongsr than standard but only in ths neighborhood of (Reference 1263-52), Experimental work was limited for the meet part to a study of the yellow component, of the green,teste being made by mulling the latter with varnish drier and blue (B-216-D) paste, A few other blues were investigated briefly but none appeared to offer any advantage* Some further work along this line would be desirable,' tallows made by the standard T-493-D procedure, (K-2009,k-2**8)^ve greens which were bluer than standard in masstone, more intense in tint and about equal in strength and lightfastnsa*. Increasing ths bichromate (with or without adjusting the soda ash) gavs a mors ysllow (olive) aasstone but no very significant increase in strength, * A closer match to standard f-*93-D was obtained by a modified (simplified) procedure similar to those under investigation in connection with eontinueusi manufacture and moat variable studies were made on formulas of this type* Attempts to increase strength by changes that might be expected to inoreaae the lead chromate content of the yellow or to decrease pnrtiole also wire only partly successful, Ths resulting products gave greens which were generally too yellow (olive) in a&sstone at the desired depth or too yollow in tint* itor* promising results were obtained by striking at a slightly elevated tsqperstur* or by the simultaneous addition of load nitrate and bichromate to a soda ash solution, Thset modifications gave greens which were light in asestoae and approximately equal in tint (equal blue content) t with additional blue, fairly strong (ea, 110/100) blue-tint greens were obtained. These represent the most premising results obtained in the present study. Some attention wasgjlvsn to a formula based on that of tho strong lesson yellow T-318-D, Tho latter is much worse in lightfastness than T-493-D but by adding stannous chloride prior to the final pH adjustment, the lightfastness is isproved to approximately that of T-493-* This procedure appears to give a slight strength advantage ever Y-A93-D but the (green) aaeston* is somewhat dull. Attempts to replace stannoue chloride with other material* were unsuccessful. Various chemicals appear equally effective in their reatfdAhing action but none gave product# of satisfactory lightfastneas. DUP050066839 As indicated above, moat of the work was baaed on a simplified Y-493-D procedure. A coagwurieon of various experimental formulas with the latter is given in the appendix* The yellows obtained by both the K-2009 and K-2448 formulas gave greens bluer and more intenee than standard and which were much alike in color. She K-2448 formula (low tin) gave v*s* worse lightfastness* Increasing the biehro* mate gave a slightly lighter and yellower onsetone and very slightly duller tint* Judging from pest experience, this variable muet be need with caution to avoid excessive reddening of the yellow* Increasing the strike teaperatur* (T5* * 90*?) gave a lighter masstone with very little ohange in tint* Variations in soda ash had very little offset in the range otudiod. These differed from Y-493-D intthat all the tin was added incediately after the strike) this was followed by the other ingredients without dm intermediate washing step* In one modification (1263-6&), F), tin 017stale, soda ash, sodium sulfide and alum are added in turn followed by more coda ash to bring the slurry to a definite pH* A further simplification (1263-66E, 0) comprised simply adding tin crystals, alum and soda ash in turn. (F ft 0 employed slightly more bichromate then D and t) * Tinctorial results were much alike with the four formulas but the yellows made without sodium sulfide wore very slightly worse in Mgbtfasiness. The simplified formulas gave products closer to standard Y-493-D than when the standard procedure was used, t*e* the greens were yellower (more olive)* A considerable number of experimental series were run to determine the effect of strike variables bn oolor and oapseially tinting strength* Fadeometer teste were run on most samples. In general, the results in respect to strength improvement were negative* The only leads were! a) the use of a slightly elevated strike temperature (See Y-493-D above) and b) the use of a simultaneous strike pro** cedure as discussed below* Both-ef these modifications gave light masstone greens with little change /in tint) additional blue gave stronger, blue tint material. Variable* aimed at increased lead chromate content or decreased particle siso usually resulted in yellof (olive) masetones and/or yellow tints* Results of miscellaneous experiments are indicated below* - 1* Omitting salt gave very olive products* Variations in the amount did not give any clear-cut effect) ths standard quantity appeared to bo satisfactory (Ref* 1263-8, 19, 44)* Adding the salt before or after the strike offered he advantage (1263-2?) 2* Replacing bichromate with chromate, i.e* precipitating at a relatively high pH gave dark masstone greens* A low pH 1 apparently necsosary to obtain the light '.masstone (blue tint) typo* (Rsf* 1263-14, 15, IT* 23, 32, |6, 49). DUP050066840 3* Th final pH before flooding m apparently not oritioal. In general, the slurries were adjusted to pH 6.0 (Ref* 1263-2, 4)* 4* High dilutione gate somewhat bluer and very slightly stronger produets (Ref* 1263-20, 4?)* 5* Addition of sodium acetate to the lead nitrate gave very dark uaaatome greens* Ibis variable should be studied further in any future work on products of the latter type, especially those based on the 1033-72 procedure (Ref* 1263-17, 19), 6* Variations in the amount of bichromate altered the aasstone more then the tint* largo amounts gave yellow products and vioe versa!* $00 high an amount gave unstable produets (Rsf, 1263-24, 25, 26, 32, 33, 35, 40). 7* Reducing the amount of aim gave tome improvement in strength but at the expense of lightfastness* Replacingthe elump with Liquor or eulfurio acid had the erne offact* The point of addition of alum does not esom oritioal* (Hof 1263-25, 38, 40, 71). 8, Because of its wsll known effect on surface properties sad its "restraining" notion, s amber of samples were made using sodium pyrophosphate in various ways* there were some indications that this gave a slight strength improvement but the results wers: not cleareut and, in most eases, llghtfsstnese was affected adversely# Addition after the tin or after the aim appeared leaet harmful (Ref. 1263-21, 23, 26, 29, 46), 9, Increasing the amount of stannous chloride (to mors then 8 grams per mole) or adding it during washing had very little offset# Stepwise addition during the strike likewise shoved no advantage. Added to the lead nitrate and thus present throughout the strike, it had a powerful restraining action giving bluish greens of peer lightfastness* (Ref* 1263-25, 26, 29, 36, 31, 33, 49, 50)# 10# Small variations in seda ash (added to the lead nitrate) were without any lesreut effoet* Omitting it entirely and striking with chromate instead of bichromate gave a dark masetone, (yellow tin# green* Too high an amount results in a "flop*# Replace ment with caustic reeulted in worse lightfastness* (Ref# 1263-22, 23, 24, 40, 41)* 11. The presence of a small amount of sodium sulfate inthe bichromate appears desirable to prevent cliveaoss# Too largo an mount results in a flop (Ref* 1263-28, 40)* It was observed that t-UlBHfclgwo grams similar in color to those made from 1-493-D but somewhat stronger. Lightfaetnees was much worse but oould be greatly improved by adding stannous chloride after the sine sulfate (Be# Appendix) DUPQ50066841 prior to the final pH adjustment with soda ash* Heat development was found to he unneoeecary, A numbr of variables were studied os this formula (1263-66A) but the work was dropped as the greens obtained were duller in maastone than those made with 1-493*5 of modification of the latter (Ref* 1263-42, 43, 4S# 531 54# 55, 58, 59, 60). rf. la vei of the favorable remits frequently obtained by precipitating chromate pigments at high dilutions, several experiments were run in which the bichromate and lead sere added from separate funnels to a sodium carbonate solution, keeping the lead in excess throughout and following with ths usual treating agents. This technique was tried out with several basic formulas and in all oases the yellows obtained gave greens which were definitely lighter in oasstone than the controls at equal blue content and approximately equal tint (Ref* 1261*#, 49, 59, 60, 63, 6?, 69). At equal meetone, they were stronger. Several blues were cospared with B-216-D especially in respect to strength of the green which they produced. The work was limited for the meat part to hoard mixes of dry blue and dry yellow* the blues included B-197-B* B-I40-D, g-6579 (soda blue), 8-63*5, B-257"5, C#-49658 (imperial 4406) and olaoellaaeouc experimental produets* Hone of these appeared to offer much promise but further work is desirable, especially the preparation of ''struck* greens using a slurry mixing technique (tsf. 1263-12, 18, 56). ^ssto,a.teiaiU8f.BM in nest of the work, stannous chloride was used as a restraining agsgf* Other materials gave satisfactory color text none was found giving equally satisfactory lightfastness. Sodium ferrooyanide, cuprous chloride, trivalent chromium end earhoxy methyl cellulose were investigated (Ref. 1263*39, 61, 62, 65, 72)* Attempts to prepare strong producte by blending *550" greens with *604'* grams were not successful* Addition of the ''iOA* type gave a yellow tint but little Improvement in strength. Old temples of the obsolete*503" line (ctrcng blue tint) were found to'have flopped.* storage. (Ref* 1263-13, 52) DU P050066842 APPEHDIX -5COMPARISON OF BHADINO W FORMULAS Soda Ash ... ................ ................................ -29.------ ,,--.29.-- Strike in 20 ad&tties vdth the following dieeolved together Bichroaate Soda ~w~~ 62 Sod. Sulfate anhyd. ? 6.5 Balt 10 10 Chem. 56 none - none Volume (striketempi ^asajisL.,.-JOajsjL S2.5/65 5 10 none ___ 62.5/65 5 10 none '"'16 3.5 none 0.6 Mi the following ^n tarn Chem, 56 Zine Sulfate (ZnBOe) fin Crystals Soda Ash Sod. Sulfide Aiun................................ none none 2 5 0.5 2 none none 2 5 0,5 ... 2 ........... none none --------------- - none none 14 44 4. 8. non# 0.5 none none 12........... .- IB............... -."non*....... ..... Adjust to pH 4.6 and Wash 3 waters yes yes no Add in turn no no Alisa fin Crystals ..... Soda Ash to . Wash Dry at 140F ... 10 2..... nH 5.0 no yes 10 none none none' ....1._..... ...none......... none ho bo nH5.b' SH M ..oB 6.0........ ..'.PH ;6ili. no 3 waters 3 waters 2 'waters. yss yes yet yss . Notes* pH of Lend Nitrate Boln. on* 4.7 pH of Biefareafcte adjusted to 4.7 1263-66 F & 0 differ fron D A B in amount of bichromate need* DUP050066843