Document aXdwRJ95GQaYq9OkpDMR3q1Y

mmm mmm m sPARU&g IllS5?RIEOTI0Jf OF PIOMEKTAinf BEEA PHASE COPPER PHTHALOCSAHEEffl By: A . R. Hanke 2 /6 / E. I. DU PONT DE NEMOURS & COMPANY KREBS PIGMENTS DEPARTMENT 256 YANDERPOOL STREET NEWARK, NEW JERSEY 'JL Serial Ho. Copy Ho. OT-51-33 15. Extra JACKSON LABORATORY FILE ROOM NEWARK PLANT PIGMENT COLOR RESEARCH REPORT Period Covered Pinal Report PARTICLE SIZE DISTRIBUTION OP PIGMENTARY BETA PHASE COPPER PHTRALOCYANINE 2/6/51 to 4/9/51 FIL& DATE: 223.41 4/19/51 KJ 1747 DUP050068601 Serial to* m-51^62 Copy Ho* Copy to? $1 ~ 'UOTs?lea3. Pile S - Research Office {225.41} 5 ~ Library 'File (225.41) 4 - Dr* U' A* Perkins - lacka on Lab* 5 - Grshsm Patent Sorri'e ~ '** * 8 ** H* 1* Stryker ** Jackson lab* 7 ** <K D* Patterson - Bs^oriaantal Sta* -Wilm* 8 " A* tr. Harney " ** -1 9 J. P Hancock " Patent Dihr#, Wi'im. 10 - w* F* Spengeroan/j. B* datlaray/p* J, Momfeaa 11 - 1. IT* ToIJLy/fU Sis gel/Library 12 - A* R- Hanks 13 * Extra 14 - }? KSKAEE PLANT PIU&TET COLOR RESEARCH REPORT Final Report PARTICLE SIZE DISTUIBUT XOM OF PIGMENTARY BETA PRISE COPPER PHTIIAlOCYAHIHB S/6/51 to 4/9/51 SUBMITTED BY? A. fi. EANKE APPROVED BY ? B. II. PERKINS DATE SUBMITTED? 4/9/51 d a t e Is s u e d ? 4/19/51 DUP050068602 Tiie recently allowed liana patent or, 55 dapper-Phtbalocyanin %n Pigmentary Beta Form and frosessi of leaking tbs Sam"# has mads it desirable to obtain particle .sia distribution estimates with sen&tfc&t greater precision than can bo had by a casual, inspection of loot*cm micrographs This report record the results of particle sit counts from electron micrographs of om* ET~?.07~B 3D 9049"? mid a typical sample of 6alo*s beta phase OPC coded 0-55926, Cyan Blue 5.5-5300* Dot 8-8024-109* Is say work designed to obtain a partial sis distribution# It becomes necessary to attempt to define ?Axat la mamt by .a partial* For a great many powdered substances a consideration of the particle Sis of the pigment consisting of cars lumps or cakes down to the very fire sub"microscopic fraction of the material# shows that there is some particle which requires considerably mors energy to reduce its else*then the other .larger- particles# This particle is usually termed the `'ultimate1' particle# si though it should be recognised that the definition of ultimata particle is net s. rigid one and an excessive hang in. the magnitude of the force of ufcdivision can finally caps a fracture of a so-called t?tjltiire.te:1! particle end a a?/ wultisateM particle rnuet be defined# Beta phase CIO of pigmentary quality is manufactured in such fashion that the mm.lt ultimate par viol is a crystal fragment* That this is so# is evident from the m&mif&etaring nroce&s, and the electron micrographs definitely show the crystalline nature of the pigment* The ultimata particle ft therefore defined a this crystal fragment as it exists in the finished pigment# In speaking of particle sis and par ticle size distribution* it is this crystal fragment that is meant and not s.o aggregate of crystal fragresnts capable of being broken down to the individual crystal fragmanba* XX# 3UMM8Y AHD QO&CXUSIOIfS 1* Both Calco * s product and our product have over 90$ of their ultimate particles of a else less than 01m average diameter* ' .2.# Thor Is m occasional particle greater than 0.*&n average diameter but it amounts to only 0*4$ for oia product and 0* 1)1 for CaleoVs product* 3* An examination of the rootangular histograms definitely shows the similarity in particle size distribution between th two products, with our product containing' somewhat more large-pertides than Calce's pigment * 4# Two average particle diameters derived from the distri bution data and the average diameter calculated from a specific surface treasuremsnt .farther illustrate the similarity of the two pigments* The diameters in microns ar given, below % Calco's Cyan BT-687-P Blue <0-55926? dn d {sp.surf*) 0*067 0,100 0*061 0.066 0.083 0*062 DUP050068603 *' 2 ~ Mate The ave* dia,, nommelatur Is fairly mil standard ised throughout the literature, (ref.) hut to amid atahigulty, any average part isle size diameter should always be defied. d* nd 5" a c% 'gTHH a nuaiber of part Isles la a size class* d " am* diameter of each .size class* iii* Exmammux. TEcmXQOEa To obtain the particle size distribution of these crystal fragment it is necessary to disperse the to the degree here size measurements can he made on Individual fragment a, using the electron microscope to get the necessary magnification* Because of the smallness of the particles in question, to get adequate dispersion is a very dif ficult procedure in which is eafcodled the technique of trial and error It should therefore be understood that any written procedure is not to be considered as yielding unequivocally suitable electron micrographs, bub, most usually, .repeated attempts must be made in which modifications are employed as to the pigment particle population, the thickness of the film supporting the pigment die parsion, the length of time the sample is rubbed, how hard it is rubbed, how long the sample is -allowed to stand in contact with the dispersing medium, etc* sieperlenee coupled to a contain amount of luck will finally yield a dispersion from which it is possible to make particle size counts on particles which appear to be, for the most part, single particles* It must be realized, however, that at least soma of these particles are probably aggregates and that a particle sis count will give a dlstri* bution with averages somewhat larger than those given If it were possible to .strictly measure single crystal fragments* A, Procedure for Fr.e;par:ing Electron Morographg A small amount of the dry pigment { + 10 mg) is mixed with about two drops of {approx* 20$ Eilfc.Foc@Xlul.ose)* This Is rubbed on a Cararra^glass suede finish plate using a small palette knife* The rubbing -time la usually 5 minutes* Thinner is added from time to time to maintain & workable though heavy ink. .A portion of the resulting Ink Is thinned with diluted nitrocellulose prepared by diluting the KV-30-TV with T-3601 In a ratio of X to 20* Such a di lution gives approx, a 1% nitrocellulose solution. This diluted lack is thoroughly mixed in with the palette knife* &Th composition of K7-36-T7 is as followss1/4 sec* nitrocellulose - 14.*9% <70$ Solids) 1/2 -sec* nitrocellulose - 14*9# (70$ Solids) DUP050068604 *Th composition of T-360I is as follows I-* Butyl Acetate 37* 0# Toluol 36 * 0$ Sbhyl Acetate 12*5# Butyl Alcohol 12 0f Ethyl Alcohol 3*6ff / Gararra glass is a structure! glass manufactured by Pittsburgh Flat Glass 0o* it comes In a gloss and a sued finish* The sued finish furnishes an Ideal surface for Intimately talking pigment and vehicle with a palette knife* One drop of this dispersion is placed on a clean microscope slide.. The edge of another slide Is used to smear the drop over the surface of the slide. The film so formed dries almost Immediately and i,s floated on to water in a crystallising dish by carefully inserting one edge of the slide into the water* The film will separate fro the slide :es the slide is further immersed until .it finally floats free. It is fall to score the film before floating it on to the water so that several isolated film sections will be floating on the water* A con venient scoring tool is & diesooting needle* Since the edge of the slide used to spread out the drop Is not perfectly straight hut contains very small ridges, the film sections are not of uniform thinness and with experience a region of the required thinness can he selected aad picked up on a 200 mesh' screen i/8* dla* In order to accomplish this, the 200 mesh screen, supported on a little brass platform equipped with a small handle. Is taken'below the surface of the water under the selected portion of the film. The screen is then raised so that it supports the selected film section* This .follows the film mounting technique also applicable to preparing mounts for electron diffraction and is described in greater detail on p* 8 of KS-46-76* The screen containing the film Is removed from the support and allowed to dry for a few -minutes* It is then transferred to the electron microscope holder* Tweeters are used to facilitate this transfer* If the image on the fluorescent screen has poor resolution, it is probable that the film Is too thick and an'other mount must be made selecting a thinner portion. If the film breaks even with a low Intensity beam current, the fils, ,1s too thin and a thicker portion must be .selected* If considerable aggregation la evident, inadequate dis persion is indicated, and another ink must be prepared* More attention should be given to the rubbing stage of the technique, particularly after the final addition of dilute f^SS-T?.* Also, in particularly stubborn oases, aging the ink for several days has been known to improve the dispersion* If the field Is too thickly populated for easy viewing or too sparse to obtain a typical representation, the whole mounting procedure must be repeated, adjusting the quantity of pigment used* In actual practice, several mounts are always made employing the variations mentioned above until a picture, or group of pictures. Is obtained which show adequate dispersion for the purpose Intended* If a particle size count is to be made, it is particularly important to have as highly a resolved image as is consistent with the practical DUP050068605 range of the mierc'sccpe* The degree of dispersion amat also be sufficient to allow the counting of enough stngl 'particles, .avoiding th counting? of afrregatea .a'a slnple canticles * B* J-Y-c g edurc for Particle Size -Counting The electron microscope yields a photographic negative S x 2" and with a magnification of approx, 6,000 X* Th actual magnification calibration will he described in mist he:? section. This negative is optically projected cn a .screen making the projected magnification 50,000 X* ' only the center portion of the negative is considered for counting in order to minimise the distortion, introduced by optical aberrations. The projection sis need for this work was 20 x '20 cm, Th screen is eross-rulcd to form rectangles to conveniently divide the counting field into cm Her sections* A convenient degree of sub division .is eight sections .of 5* x 10 cm each. Actually the -sis section most convenient will vary with the population density of the particle and any degree of subdivision my be used. Inspection of the particle sices will suggest a suitable size interval* For this work, the sis intervals chosen were "? 04Q?t4 0*40M to 0>3^u , 0.3'Qm to 0*29m , 0.20^ to 0,V^u , 0*19*4 to 00^i4 , wxm <QQ&j a 0,0x The precision of masuremonb was as enlac'd to be around To automatically obtain an average dimension for particles' that are non-sphsrlcal in shape, linear measurements were made always in the same direction* This assumes random orientation and .is an .ac cepted technique .recorded in the literature (ref)* The direction chosen is immaterial* For this *orfcr, measurements were made horizon tally. Care should be exorcised in avoiding the counting of aggregates as single particles* There is no good rule to follow to completely avoid this and undoubtedly some aggregates will be counted as single particles* An accepted rule to follow is to not count a particle unless one can-.sec at least half of its perimeter* in actual practice the particles are measured with a pair of dividers, starting with the largest size range first For this work very few particles exeeded 0*29*4 hence th first two classes could be counted and totaled more or less simultaneously The next class, 0o8p<a to 0ig4 is counted by setting the dividers at 0 Hu and counting all particles 0,.3Lfci and over which have not been counted in the previous range The "dividers are then set at and all particles 0,,0^u and over which have not been counted in' the previous range are counted and at the same time all particles under 0= are also counted* This technique is, of course, applied to each of the subdividing rectangles To avoid counting the same particle twice at the boundary line between adjacent rectangles, the particles touching only the left and upper sides are counted with each rectangle* This follows the accepted practice of blood cell counting The sums for each rectangle are totaled to give the number of particles in each size class \ \ DUP050068606 5 0* Procedure for Magnification Calibration Two independent methods were used to obtain ah absolute measure of the marpilfieation,, One method was to oast a nitrocellulose replica of a grating designed for this purpose and marketed by Baird Associates* This is a ruled grating with 15,000 lines to the inch making the dis tance between line centers 1*7 microns + 23 apart,. The replica is prepared by spreading a solution of nitrocellulose in amyl acetate over the grating and then floating it off on to water* 'This film is then picked up on a mounting screen in the conventional manner* The actual distance apart of the lines on the photographic negative measured with a cm* rule and expressed in microns divided by 1*7 microns gives the magnification factor for the electron microscope* Care must be exer cised in maintaining the same conditions with regards to instrument magnification for both the grating picture and the pigment pictures* Of particular importance is the maintaining of a constant position of the wpols~pieeeB in the electron microscope. Even a slight change in its position can markedly change the magnification factor* In spite of the seeming simplicity of this method, the mounting of a nitrocellulose film replica of the grating without introducing some distortion is practically impossible* A certain amount of shrinkage and distortion of the film upon drying is also a recognised source of error* Because of this, another independent method was also used to establish the magnification factor* This other method appears quite involved but actually it is felt to be mors reliable than the grating method* The primary standard instead of being a grating Is a light microscopic stage micrometer with lines 0*01 am apart* A light photo micrograph of this stage micrometer is taken at a magnification of approx. 700 X* For this work, a 44 X objective with a SO X Hyperplane ocular, and 18*2 cm tube length was used* The negative was a 4 % 5 inch Eastman 40 plate* The magnification factor for the light micro scope is thus obtained by simply dividing the line distance on the photographic plate by the line distance of the lines on the stage micrometer* A light micrograph, at this magnification, is then taken of a hole in an electron microscope specimen sereen* This hole is produced by enlarging one of the holes in a 200 mesh screen with a needle* Inspection of such a hole usually reveals enough rough edges and burrs to serve as measuring points for calibration purposes. A convenient measuring point is chosen large enough to measure on the 4x5 light micrograph negative but not so large that it will exceed the sis of the field in the electron microscope when used at low power* The true size of this distance is obtained by dividing the measurement on the negative by this light microscope magnification factor* For the sake of illustration, call this distance "AW* A low-power magni fication electron micrograph negative of this distance is now obtained sad the magnification factor of the electron microscope at low power is calculated by dividing the measured distance on the negative by WA% Inspection of this electron micrograph negative \yill reveal sufficient small structure large enough to make a measurement on the electron micrograph negative but small enough to lie within the field at high magnification* The true size of this smaller distance is obtained by dividing the distance as measured on the negative by the magnification factor of the electron microscope at low magnification* Call this dis tance ''B'*. A photographic negative is now obtained of this region of the hole in the specimen screen and the magnification factor for the DUP050068607 *" * electron microscope at high magnif icatlon is obtained by dividing the distance as measured on the negative by the distance !,B% This is in the neighborhood of 6,000 X but must be redetermined by reraeasurement of the image of nBsJ each time the pole-piece of the microscope is moved* In actual practice it Is advisable to make more than one measurement in each size range and average the resulting magnification factors* The overall precision of the m&gnifldation factor of the electron microscope is better than A typical comparison of the low power magnification factor using the two methods outlined above is 660 for the grating and 667 for the stage micrometer In projecting the photographic negative of a pigment dispersion under high magnification, the distance of the projector from the viewing screen is so chosen that the projected magnification is 50,000 X* it is at this magnification that the particle else count is made A cen timeter rule with half millimeter divisions is used to make the particle size measurements* The precis ion of the measurement is not fixed by the degree of subdivision of the rule, but is fixed by the uncertainty involved in defining the edge of the particle* If one assumes a pre cision of + 0*6 mm, an 0*1/4 particle can be measured with a-precision of 10;t t EIs means that "the magnification factor contains less error than the final particle size measurement* A fair estimate of the over all precision in particle size measurement is therefore 12$.* D* Data for BT-297-P and TJalco^e Cyan Blue Pour electron micrographs with dispersions suitable fes? counting were obtained of BT-297-D and are Illustrated in Figures 1, 2, 3, and 4, The actual particle size count is shown in Table I, Two electron micrographs with dispersions suitable for counting were obtained of Calco's Cyan Blue and are illustrated in Figures 5 and 6, The particle size count is shown in Table XI. Figures 7 and 6 are rectangular histograms of BT-297-D and Calco* s Gym Blue respectively plotting particle frequency against size class using the grand totals shown in Table I and II. Table III shows the pertinent statistical data which well illustrate the similarity between our sample and .Calco*s sample. Specific surface measurements were made on the two samples at the Experimental station using the nitrogen adsorption technique* These data are also given in Table III DUP050068608 H 05 (.0 O o -a t0 SO tS<-Kjl 05 b- 05 05 0 3 SO - tO j HIXO O to to to H 55 H P TO Ha p o tO'tPso HO 05 0 H *0 tO H CO H 10 g-cocoss^t H OS W Eh 04 fr- 03 4 05 CM 05 05 t 04 H 03 tO tO !> SO *3* CO H SO a H tO ^ O EH OOOH OOO O rtHtMO - O04 (*O}* to4` H H H rt fhrH*OtOS?i]l H03t0^ H to3 04 to 04 <i i O FQ < % :JW O c wo O - 6 M H Q03 i .EH o fH "S'S o -X o b p <4 Eh Md O a b to; If to }-? EH: Kl < Pi o TO H lV p O Eh 0 o% D-aO ttp o o *> 05 too Oea 0to" to 3 H03100 CO 03 ri H H to4 < > 10 to H 03 0) to H 04 .9 OH H oo oo coot osfl t^o Hrl too o to HTO P O Eh i TO fc O (tti | * PP M -p *vtO*HO <NH B<B O 4(05 03 H* g'TO h 5S4 ri45 0t IO i Is if.si ag o 03 P P TO P H p 13 *>$04 6Oh OP ra a 4-5 h B rt 03 00 SO Pto Ho O H P _ P TO MH P <HP fg|dfl PpapgSi ra p3fe eSfs4t p 5 g OP > O O H TO P g N H TO arl flf Prt TO H0 g S5 &8 TO H fe 0 ~ j? U Jk t> > O O St a ro goH gO t)J4 OH PP S PH < rt H tO>A. QO*. H0TO HO H TTOO V _ PH P P d H TO ft Uo N 0 OS) TO B *o>r! TTOO h tO is o 0P 6 DUP050068609 3 SABLE III STATISTICAL SWIARX BT-897-D Total So* of particles counted 2,510 Particles no greater than 0.1 micron ave* dia* 92*4$ Particles in the range 0*1 micron to 0*s micron ave* &ia,, *7*2% Particles greater than 0*3 microns ave* die. 0*4$ Av, particle dia* ndxi? {microns) 0*067 Ave* particle dia. nd^ {microns) 0.100 Ave, particle dia. calc, from specific site face (microns 5 0*061 Cairo's Cyan Blue 1,4X6 97,1$ 2*8$ 0*1$ 0*066 0,083 0*062 The average diameters di and <% were calculated from the data in Sables I and it -using the following formulas!- a hus&er cf particles in a sis class* d ss ava* diameter of each size class* The nomenclature followed, is that generally found in the literature {ref*) The average Hamster svdj.!? is called nMssn -diameter** The average diameter Kdg!? is called '"Bean volume*sin*face diameter'* This *dgB diameter is the same type of average as that obtained directly from a specific surface measurement* in Table IXX., the average diameters calculated from specific surface measurements pare calculated from the formulas- _____ DUP050068610 > 9 - 4 sp surf* sp surf* '** Diameter jcpre.sa.ed as microns Sp Gravity w 1*84 S'p. Surf* expressed as sq * meters per gram xxx. Dxscussxoi Shore is a defia.it similarity between the two pigment a -with Caloo's product containing a somewhat larger percentage of small particles then our pigment* As expected, the two averages dx and dg are .not in agreement* $fce &i average favors the smaller particles, hence its value will he lower than the % average* She dg average is of the type calculated from specific surface data but the' agreement between dg and that calculated from specific surface is not particularly good* It is felt that the biggest single factor responsible for the lack of agreement is the extreme difficulty of avoiding the counting of loose aggregates as single particles, She nitrogen' molecule does not have this difficulty and hence indicates a smaller average diameter* The resolving .power limit of the microscope is also a factor which will tend to give a measurement larger than the true site* She closer the particle diameter is to the resolving power of the instrument, the .greater will be the error* She resolving power of the microscope is probably around G.Gl,cf. Shis is still a five-~fXd factor below the 6*051# particle sise which Is prob ably close enough to have some effect out not as great an effect as the counting of aggregates as single ultimate particles* XV * FifidEE PHOGBAM It is planned to obtain particle alas distribution data on other pigments as time permits V* RdPSREMCES '& IC. Fisher "Colloidal Dispersions", Xohn Wiley & Sons Ino* ITew fork 1950. The experimental work is recorded In KB-HS7-76 & 77. AHHslg _________ DUP050068611 - 10 Figure 1* BT-297-D, SD-90497. Plate 1471 35,000 X DUP050068612 - 11 2, BT-297-D, SD-90497 Plate 1291 35,000 X DUP050068613 12 Figure 3, BT-297-D, SB-90497 Plate 1457 35,000 X { DUP050068614 - 13 - Figure 4. BT-297-D, SD-90497 Plate 1458 35,000 X DUP050068615 14 - 35*000 X DUP050068616 15 35,000 X DUP050068617 P a rtic le Frequency - 1'6 FIG 7 B$ "297**1) SD-S0497 DUP050068618 P a rtic le Frequency 17 4* FIG. 8 OALCO'S GY.AH BLUE C~S39S0 DUP050068619 DUP050068620 DUP050068621