Document wqgqr3vvdgGYoo54aX66qv0Bd

E. I. DU PONT DE NEMOURS & COMPANY KREBS PIGMENTS DEPARTMENT 256 VANDERPOOL STREET NEWARK, NEW JERSEY Serial No. R8-*45~lS> Copy No. 1 Numerical Pile . ,* V ^vi' ^ ' .O" / ~A Period Covered: NEWARK PLANT PIGMENT COLOR RESEARCH REPORT Fiagl Stejmrt a^T^P. PUMP 8T8DY BASSO ON SICK .IS$ *98X BSQOSST #34 0&CBKBB8, 2944 - 194$ FILE: DATE: 223*72 VW+5 Njatu N37974 Serial Bo. KB-45-15 Copy Bo. i Copy tot #1 - Numerical File 2 - Research Office (223*71) 3 - Library File (223.71) 4 - #10 Building File 5 - # 6 Building File 6 - Imperial Chemical Industries. Ltd. 7_ ft tl H 3,, t It H ft -9 - Mr. J. H, Bailey, Newark/Mr. R.4.Kaiser, Wilm. 10 - Dr. D. H. Dawson/Dr. E.R.Allen, Newark - y~ NEWARK PLANT PIGMENT COLOR RESEARCH REPORT Final Report TITLE* GT-76-P, PLANT STUDY BASED OB SICK LIST WORK REQUEST #34 Period Covered* December, 1944 - February, 1945. SUBMITTED BY: E. J. Hess DATE SUBMITTED: 4/4/45 APPROVED BYt V Chalupski jCC'ildJhJlsh- * DATE ISSUED* //^. fffr 4/18/45 DUP050149985 la December* 1944, the erratic results being obtained In plant (KE-76-P production aade it necessary to place the manufacture of this pigment under the supervision of the development Section. Sick list charge #34 was opened to cover the cost of this work. In the work request issued by the plant, a number of possi bilities were suggested as tb the reasons for tins tendency toward weakness and the undesirabla gelation effect being seoured. These included* 1. The possible variation in agitation during the strike due to the use of a make-shift procedure (belt slipping) for securing a necessary slow agitation rate for control of water bleed. 2. The use of copperas crystals on an "as is" basis (possible 5-10% variation in PeSO^ content). 3. Poor press washing. 4. High dry content of the standard pulp, lot 93214. 5>. Unsatisfactory dupllcabillty of the brushout testing method. Results on a total of twenty-four hatches are available for this report. A new standard GT-76-P formula, K-2133, has been written based upon the Information developed during this sick list study.* 1 2 3 A preliminary investigation of conditions under which GT-76-P was being manufactured and tested during the period immediately preceding and just following the issuing of the work request disclosed the following undesirable factorsi 1. As indicated by the plant, "belt slipping" as required to meet the agitation rate specified in the "non-bleeding" formula could result in variable stirring daring processing which might affect quality. 2. Also as indicated by the plant, the addition times specified in the non-bleeding formula could not be met without the use of an extra vat for dissolving the soda ash added after strike. 3. Hot wash water had been used in a few batches by the plant in an attempt to facilitate press washing,Temperatures as high as ll?-120oP (coming through the press) had been used whereas the optimum develop ment temperature for the color is 104P. DUP050149986 2 4. Dry contents of the crude press cake had been running below 30# (normal* 31-35#) whioh may have been due to the failure to maintain the gauge pressure at 125-135 lbs. during the full 35-40 hour washing cycle. 5. Abnormal color bleed during washing which seemed to be the result of using In incorrect grade of filter cloth. This, of course, played a considerable part in the failure to maintain normal washing condi tions because of the color bleed from the filter press at the higher gauge pressures. 6. The press was noticeably corroded, ports were plugged, etc. A thorough cleaning was necessary. 7. The standard GT-76-P, lot 93214, in use at this time, was objectionable on two accountss (a) It is of the "bleeding1* type so that all batches tested must be better In this characteristic than the standard. The actual bleed of the lot to be tested, therefore, could only be estimated with the usual testing procedure (spot test versus standard). (b) At the time lot 93214 was tested against the previous standard (lot 26422) strength was satisfactory on an "as is" basis at 27.4# dry content which was within the desired range (27.0-27.5#s. However, at the time the new standard was set up (two or three weeks later) the dry content had increased to 28.5# and the standard, lot 93214, has been used at this figure up to the present. Matching this standard, therefore, has resulted in giving away approximately 4# of strength as It has been necessary to maintain dry contents at 28.5#-29.0# instead of the original specification. Manufacture under Development Section supervision may be divided Into two groups* I-Production designed to correct manipulation and pro cessing deficiencies in the "non-bleeding" formula for OT-76-P (modified K-1439). II-Production using new variables in an attempt to correct weakness and gelation difficulties. This was made necessary by the failure of ordinary control variables to accomplish the desired result. DUP050149987 3 In any discussion regarding control of quality on Pigment Green B, on a batch to batch baa la t it should be realised that .even under the beat of circumstanced, significant teat results are not avallabta until ten days after the start of manufacture while in many eases two or even three weeks* time elapses before final con clusions as to quality may be drawn. Attempts were made in this 1 study to secure some advance Information as to tinctorial properties by obtaining brushout tests on vat control and crude press cake samples but the results were inconclusive as will be discussed later in this report* Production under Group I consisted of thirteen batches. Two corrections in the making and processing procedure were made at once, i.e., an antra vat was used in preparing the soda ash solution in advance so as to make it possible to maintain stirring times in the non-bleeding formula and the use of hot water to speed up press washing was stopped. The variables used And the results secured follows (a) light batches were made using the non-bleeding formula except that 180 pounds of copperas in solution 100# (N-24) were used to replace the same amount of copperas crystals "as is** (1-391) It was during the course of this series of batches that it was discovered that the supposed *low grade*' of #8 duck press cloth being used was really XX chain cloth* This type has always given considerable trouble in Pigment Green B filtration especially during the washing cycle and is definitely not recommended. Although the press was cleaned and scraped and the correct type of filter cloth used in five of these batches, there was little, if any,quality improvement and the dry content of the crude press cake remained low in spite of the normal pressing conditions. Attempts to increase the density of the cake by decreasing pressing volume by 5# and by sandwiching Kraft paper between the press cloths were not successful. A further indication that poor washing was not entirely responsible for quality difficulties was that ten attempts to re-work part of two batches by re-filtering and washing in the semi-works gave practically no improvement. Under-washed Pigment Green B pulp normally responds to this treatment. Of the eight batches In this series only one was O.K. to ship. Two of the remaining batches were shipped straight although both showed a noticeable galling tendency and one was weak in tint* (b) Two batches made to check exactly the non-bleeding formula (180# copperas crystals) were unsatisfactory* One was sub-standard in both strength and gelation, the other in strength only* DUP050149988 (c) A check to the original K-1439 proqsSure (fast agitation, increased strike and sfirrih*: times) except fon- tlio use of- 180# copperas- C10Q$> in solution Instead of Sfq# copperas crystals uas is** finished %p G.K. tlnot<iall^ inf ussatisfaetoiy in bleed and gelation. (a) Revision of the strike and stirrin^vtiiaes to conform to the non-bleeding formula but retaining thafast agitation rate (20 BPM) gave, a product thatwaa standard in colJr 'and in gelation hut sub-standard lhblaed. fa attempt to Improve the bleed by using an intermediate agitation tail (15 aPM) gave the deaired non-bleeding product bat color and gelation mere unsatisfactory* An examination of the results obtained in the above series of batches indicates that only one of the variables tried, the use of increased agitation rate, gave any definite improvement in tinctorial properties and this only at the expense of bleed resistance, delation and density of the crude cake remained abnormal. After some discussion with the laboratory regarding other variables not in general use. It was decided that,in view of the blueness and dullness of tint of current production, a decreased copperas amount might be tried, in examination of the formula shows that the ISO pounds of 10055 copperas figure is equivalent to a 4-1/25? excess disregarding the probable loss of Beta Kaphtho! during the nitrosatiom. esterification and clarification procedures. It was finally decided to cut the copperas amount to 170 pounds 100$ using the analysed solution. This weight is theoretically equivalent to a 1-1/2$ deficiency of copperas (172-1/2# FeSOA.7%0 100$ is the theoretical figure for the standard 273 pounds^of Beta Paphthol) but if losses are considered this amount may represent a very small excess (as indicated by the spot test). Production under Group II, therefore, consists entirely of batches made with decreased copperas amounts. These are divided as follows! (a) Wine batches were made to check the "non-bleeding1* formula except for a decrease in the copperas from ISO# 100$ to 170# 100$. Of these seven were "O.K. straight" and tw were sub standard (one was too weak and the other was deficient in gelation resistance). This is considered fairly satisfactory performance for this color as the occasional batch sub-standard by brushout or beater test can easily be consumed in lake manufacture or as the rubber color, GT-68-P (when active). Unexpected effects of this new variable was the improved gelation and the return to normal dry content (31-35$) of the crude press cake. DUP050149989 -5- (to) While awaiting results on the first trials of the low copperas amount, a single batch was made adjusting the ester pH close to neutrality prior to the strike. Shis variable had been used In the production of 01-646-D (dry Pigment Green B) to obtain Improved strength. An unsatisfactory weak product was obtained in this case. (o) A single batch made using a further decrease In the copperas amount to 165 pounds 100# was O.K. to ship but showed no better than average quality (2# weak - ws blue and dirty). As this copperas figure corresponds to a 4-1/2# theoretical deficiency and because of the very slight yield loss, It was decided to standardise on the basis of the 170 pound amount* In attempting to set up a shorter time cycle for deter mining the quality of a batch, a number of brushouts were made on vat control and crude press cake samples. Only tinctorial quality tests can be obtained in this way. The brushout procedure used differs from the standard method, TP-52-9, in that it is necessary to screen the color mixture before brushing. The results received are shown in the following tables Total batches tested* 15 Batches on which both crude press cake), 4 and vat control tests are available ) Vat control tests only* 11 Performances Crude press cake and vat control testss Finished! 2 SG in color and gelation; 1 NO gelation only; 1 NO in color only; none O.K. Crude press cake! 3 NO In color; 1 OK in color Vat control* 1 NO in color, 3 OK in color Vat control testss Finished! 3 NO in color and gelation; 2 SG in color only; 2 NO in gelation only: 1 NO in gelation and bleed; 1 NO in bleed only; 2 OK Vat control! 5 in color, 6 OK in color. DU P050149990 An examination of the above results shows that although both vat control and crude press cake results are fairly significant tinotortally (crude press tests were 100$ In agreement with finished product resultss vat control results showed 73$ performance), the remaining Important characteristics that Is, gelation and bleed, Interfere to such a large extent as to seriously affect conclusions* Thus, final performance figures would be - crude press cake results, 25$ accurate} vat control results, 22$ accurate* An attempt was made to set up one of the first OK batches made on the new formula, lot 20610, as a new standard on the basis of its satisfactory quality and dry content (27.5$). Unfortunately, however, although it passed the ordinary gelation test (24-48 hours standing without noticeable gelling tendency) two months standing resulted in definite gelation and the batch was not acceptable as standard* Testa are now being run on a second batch, lot 21623, preparatory to restandardleatlon* Although,with the selection of the proper formula, quality difficulties that have been ascribed as possibly due to variation in agitation resulting from belt slipping have disappeared, a project has been approved to replace the belt drive on the strike vat, vat 202, with a variable speed drive* Average yields since the density of the crude cake has returned to normal have Increased from 94.8$ of the goal figure to 99.6$. The single batch made with 16? pounds copperas (a probable deficiency) finished up at 98.7$ of goal. A new formula for GT-76-P based on the modified non-bleeding formula has been written and coded K-2133* Hew formulas (based on K-2133) for the other Pigment Green B pulp colors, GT-68-P. GT-75-P GX-79-P have also been written and coded K-2134, K-213? and K-2136 respectively. ?AL DETAILS; DSN-45-6. MPH DU P050149991