Document yrD8B95d6dJVKbRQa66pkMrZn

-KSf-69-7 CRYSTAL STABLE &-CCPPER PHTHALOCYANINE BT-465-D, BT-466-D By: H. h fe tric k 5/67 12/68 P Dept. Jackson Laboratory R. & D. FUe Room TO:____________ Return to; CDPDept. Jackson Laboratory R. & D. File Room TO-.____________ Return to: CDP Dept Jackson Laboratory R. & D. File Room TO:____________ Return to: CDP Dept. Jackson Laboratory R. & D. File Room TO: Return to; CDP Dept. Jackson Laboratory R. & D. File Room TO:_____________ Return to: MU-1760 (Rev. 3/767 CDP Dept. Jackson Laboratory R. & D. File Room DUP050081420 `*2 E. I. DU PONT DE NEMOURS & COMPANY 2S6 VANDERPOOL STREET NEWARK, NEW JERSEY Serial No. KN-69-7 Copy No. 15 RETURN TO JACKSON LABORATORY FILE ROOM NEWARK PLANT PIGMENT COLOR RESEARCH REPORT CRYSTAL STABLE (3-COPPER PHTHALOCYANINE BT-465-D, BT-466-D Period Covered jjay, 1957 _ December, 1968 (Part Time) FILE: 223.41 DATE: 3/7/69 NJ 14071 DUP050081421 KN-69-7 1. Numerical File 2. Research Office File, Newark 223.41 3. Newark Library File 4. M.Hunt/E.Gonick, Pigments, Wilm. 5. W.S.Struve/A.A.Brizzolara 6. F.F.Ehrich/H. H.Gyorgy/B.H.Perkins/fcrewark Library 7. A. R. Hanke/J. Jackson/E. E. Jaffe/Newark Library 8. P.J.Monahan, Newark {Vital Records) 9. N.G.Fisher, Central Research, Wilmington 10. R. H.Wetze)., Newport 11. J.F.Maurer/J.W.Minnich/Colors Research File, Newport 12. H.Matrick 13. Extra 14. Extra 15. Extra 16. Extra 17. Extra NEWARK PLANT PIGMENT COLORS RESEARCH REPORT SUBJECT: CRYSTAL STABLE 0-COPPER PHTHALOCYANINE BT-465-D, BT-466-D PERIOD COVERED: May, 1967 - December, 1968 (Part Time) SUBMITTED BY: H. MATRICK Date Submitted: 2/12/69 APPROVED BY: F. F. EHRICH//. t.e% Date Released: 3/7/69 ABSTPRCU Addition of CPC-AF to the p-CPC's, BT-297-D and BT-383-D gives products superior to the respective standards. The new products, BT-465-D and BT-466-D, respectively, offer improved tinctorial and working properties in paint and improved heat stability in high temperature plastics. DUP050081422 TABLE OP CONTENTS Page I. SUMMARY AND CONCLUSIONS 1 II. PATENT STATUS I III. INTRODUCTION 1 IV. DISCUSSION 2 A. Crystal Growth - Organic Solvents B. Plastics Applications 2 3 1. Neat Stability 2. Warpage Resistance 3 5 c. Paint Applications 6 1. Tinctorial Properties 2. Working Properties 3. Humidity Resistance 4. Lightfastness 5. Other Phthalocyanines 6 7 8 9 9 D. Ink Applications 9 V. APPENDIX A. Preparation of CPC-AF, CP-87,Example I 10 B. Crystal Growth by 0-CPC and Inhibition by c p c AP in 1-Chloronaphthalene, CP-87,Example II 11 C. Electron Micrographs: CrystalGrowth and Inhibition 12 D. Check List, BT-465-D 13 E. (B) Process for BT-465-D 18 DUP050081423 I. SUMMARY AND CONCLUSIONS It has been demonstrated in solvents such as 1-chloronaphthalene that 3-copper phthalocyanine undergoes crystal growth to a considerable degree in spite of it being the most stable CPC phase. This tendency toward crystal growth becomes apparent as loss of tinctorial properties in paint systems and poor heat stability in high temperature plastics. These deficiencies can be overcome by the use of a crystal-growth inhibitor, the substi tuted CPC, CPC-AF, admixed with 3-CPC. BT-465-D (1596 CPC-AF + BT-297-D) offers improved transparency and strength over BT-297-D in systems where the latter undergoes crystal growth during dispersion such as in polyethylene and acrylic lacquer. BT-465-D retains the good dispersibility of BT-297-D but also offers improvement in such paint properties as gloss, mill-base viscosity, and flocculation resistance. BT-465-D, because of superior dispersibility, has greater strength and trans parency than BT-417-D in low work dispersion such as sand milling. Superiority over BT-417-D in high work dispersion is believed to be due to the superiority of CPC-AF over monosulfo CPC as a crystalgrowth inhibitor in organic systems. BT-465-D, prepared in the Semi-works, has been released to the trade, specifically to Detroit automotive accounts. A previous sample was released to Marbon chemical for plastics evaluation, as was BT-466-D (1596 CPC-AP + BT-383-D). The latter has somewhat superior heat stability and intensity vs. BT-465-D, but is not as transparent in paint* This makes BT-465-D the more versatile product. II. PATENT STATUS A composition of matter patent claiming mixtures of 3-CPC and CPC-AP has been applied for (patent application 1702K). Ill* INTRODUCTION In May, 1967, several CPC samples were submitted to chestnut Run for evaluation of both warpage resistance and heat stability in linear polyethylene. Warpage resistance was marginally im proved with a BT-297-D sample, dry blended with CPC-AP. More importantly, this same sample showed far superior heat stability relative to BT-297-D. In order to extend patent coverage to systems other than plastics, crystal growth inhibition by CPC-AF was studied in heated solvents, paint systems, and ink systems. The paint study demon strated the valuable properties of BT-465-D prototypes vs. commercial products. Chestnut Run and F. and P., Flint have since confirmed these results. These properties are available in the red and intermediate shade CPC's but have not been available in the green-shade 3 phase. DUP050081424 --2 IV. DISCUSSION A. Crystal Growth - Organic Solvents crystal growth of a-phase CPC in organic solvents such as xylene and acetone is well-known. Since CPC is very insoluble in these solvents, extensive crystal growth was explained on the basis of the phase conversion of a- to 0-CPC as being the essential driving force. Under more drastic conditions, similar crystal growth can be demonstrated for the relatively stable p phase. Solvent-milled P-CPC, BT-297-D, was refluxed (264C.) 1/2 hour in 1-chloronaphthalene with and without CPC-AP. A detailed procedure can be found in Appendix B, p. 11, taken from Patent Proposal CP-87, Example II. The degree of crystal growth was evaluated by three methods as shown in Table I. TABLE I CRYSTAL GROWTH OF BT-297-D AND RETARDATION BY CPC-AF Approximate Avg. Particle Size, Longest Dimension by Electron Microscoov Before reflux After refiux to After reflux with 15% CPC-AF O.lp. 2. Ojj, 0.2p, X-Ray Line Broadening . Oi/s > 7.p 9.2 13,9 8.6 15.2 8.8 10.0 11.3 Relative Tinctorial Strength bv Rubout 100 250 105 Electron micrographs show up to a twenty-fold increase in particle size after reflux whereas the CPC-AF-containing sample shows only a two-fold increase. These micrographs are shown in Appendix c. This twenty-fold increase is reflected by a 60% loss in tinctorial strength (100:250). Surprisingly, a two-fold increase in particle size causes a 5% loss of strength. This can be explained by counterbalancing the strength loss due to increased crystal size with increased ease of dispersion. The X-ray line broadening data (Pi/2) is interesting in that it demonstrates the greater sensitivity of this measurement to particle size changes below 0.2(x than above 0.2n. The 8.6 and 8.8 values are probably good measures of instrumental line broadening*. It is likely that particles smaller than 2.Op, will give the same values. BT-297-D, by was shown to undergo crystal growth in both kerosene and trichlorobenzene. Surprisingly, CPC-AF retarded crystal growth in kerosene, but not in trichlorobenzene. Attempts were made to prepare pigmentary CPC by reacting urea and phthalic anhydride in kerosene using up to 40% pre-formed CPC-AF, but the experiments failed to yield a pigmentary product. See Azaroff and Buerger, The Powder Method, 1958, p. 255, Maple Press, York, Penn. DUP050081425 -3- B. Plastics Applications 1. Heat Stability C. w. Manger* has shewn that pigments undergo changes at higher temperatures in plastics because one or more of three factors s a. Chemical decomposition. b. Dissolved pigment# i.e.# pigment which has dis solved at the higher temperature# but remains in solution after cooling (supersaturation).* c. Crystal growth. Use of crystal growth inhibitors such as CPC-AF improves heat stability where primarily mechanism (c) is operating, copper phthalocyanines do not appear to undergo chemical decomposition at plastics fabricating temperatures but, in certain cases# notably in polystyrene# mechanism (b) is important and heat in stability is not much improved by CPC-AF. Two products have been developed containing 1556 c p c -a f : BT-465-D is a physical mixture of 8556 solvent-milled (3-CPC (BG# N-657) and 1556 CPC-AF (N-873). BT-466-D is a physical mixture of 8556 dispersion-milled a-CPC (BCD# BT-395-P) and 1556 CPC-AF. Both products showed improved heat stability over their untreated counterparts in injection molded linear polyethylene at 0.1 per hundred weight of resin (phr). Heat stability of untreated CPC's in plastics is largely governed by three important variables: a. Solvent potency of the plastic (solubility paraparameter# etc.) b. Temperature of fabrication. e. Pigment "concentration." At high concentrations# heat instability is mashed; at low concentrations# a greater per centage of pigment remains in solution. As a function of these three conditions, i.e.# a given plastic at a particular temperature and pigment concentration, 8-CPC will behave in one of three ways: a. The untreated CPC (BT-297-D)will show good heat stability. b. The untreated CPC will show poor heat stability and respond to CPC-AF treatment. c. The untreated CPC will show poor heat stability and will not respond well to CPC-AF treatment. Condition (a) is found in poor solvent and/or low temperature plastics such as polyvinyl chloride. Condition (c) is found in good solvent and/or high temperature plastics such as polystyrene, condition (b) is found in intermediate solvent plastics such as polyethylene. *k n -68-4 DUP050081426 -4 - Evaluation of BT-297-D and BT-465-D in polyvinyl Chloride by the Newark Evaluation Laboratory gave inconclusive results since the particular PVC fomulation undergoes a considerable degree of yellowing during the heat test. In any case, it appears that BT-297-D is sufficiently stable in this application. To confirm this, BT-297-D was subjected to dioctyl phthalate for 1/2 hr. at 400P. , a test often used to determine pigment heat stability in PVC. No loss of tinting strength was observed. Evaluation of BT-297-D in "Zytel" 101 by the Plastics Department showed excellent heat stability at 590F. vs. a 560P. control. Since the material was evaluated as a masstone, the good heat stability may be due to a pigment concentration effect. Similar results were obtained in "Lucite*' acrylic resin. At the other end of the stability spectrum, evaluation of BT-297-D in polystyrene shows a green shift at 600F. vs. 400P. Little improvement is obtained using CPC-AF. The effect is most pronounced at 0.01 phr and is believed due to dissolved pigment absorbing at shorter wavelengths than the dispersed pigment. The first evaluation of BT-465-D heat stability in linear polyethylene was carried out in Work Request NC-67-14 and results are summarized in Table II. TABLE II HEAT STABILITY BT-297-D vs. BT-465-D POLYETHYLENE 0.1 phr 450 500 550 600 BT-297-D, PS-98150 875 BT-297-D, PS-98150 + 15% CPC-AF 10 10 10 4 9 After this initial lead, a more extensive evaluation was carried out using both BT-465-D and BT-466-D as summarized in Table III. DUP050081427 5 TABLE III HEAT STABILITY BT-465-D, BT-466-D POLYETHYLENE 0.1 Phr BT-383-D BT-383-D + 15% CPC-AF wet blended BT-297-D BT-297-D + 10% CPC-AF wet blended BT-297-D + 15% CPC-AF '* " BT-297-D + 20% CPC-AF " " BT-297-D + 15% CPC-AF dry ' 450 5 9 6 7.5 8 8 8 500' 4 8.5 5 6.5 7 7.5 7.5 550 3.5 8.5 4.5 6 6.5 7.5 7 600F. 3 8 4 5.5 6 7 6.5 BT-466-D appears to have superior heat stability vs. BT-465-D. The former is also stronger and more intense. However, BT-465-D has greater potential usefulness in the higher volume paint market and, therefore, is more likely to become commercially available. The results indicate increased heat stability can be obtained at the 20% CPC-AF level. Note also that wet blendings are slightly inferior to dry blending but the latter is impractical since it involves thorough washing of CPC-AF presscake. A third evaluation at Chestnut Run in polyethylene is shown in Table IV from Work Request NC-67-22. A* a compromise, for paint properties, 15% CPC-AF was chosen but it should be remembered that optimum heat stability may require about 20% CPC-AF. TABLE IV HEAT STABILITY BT-46B-D POLYETHYLENE 0.1 phr BT-297-D BT-297-P + 5% CPC-AF BT-297-D + 15% CPC-AF BT-297-0 + 25% CPC-AF 450 8 8.5 9 9 500 6 8 9 8 550 4 7 8.5 6.5 600F . 3.5 5 7.5 6.5 As pointed out earlier, the degree of heat stability imparted by CPC-AF is dependent on pigment loading. At 0.01 phr, improve ment is definitely less than at 0.1 phr. At higher orders than 0.1 phr, the performance of the untreated material improves thereby showing less improvement by CPC-AF treatment. Other plastics in which BT-465-D and BT-466-D should perform well in are non-linear polyethylene, polypropylene and acrylo- nitrite-butadiene-styrene polymer. 2. Waroace Resistance - Reference: NC-67-14, HC-67-22, NC-68 Little information of value was obtained from warpage studies. This was because techniques for testing this property were not properly standardized. Furthermore, unpigmented resin it self is subject to warpage in addition to contribution from TiOs. Several bits of information were developed (See n c -68-11, NC-67-22) which might prove useful to future workers in this field: DUP050081428 -6 - a. Alathon 7050 appears to be the linear polyethylene that should be used for warpage tests since unpigmented resin shows only slight warpage. Alathon 7040 is less desirable in this respect. b. To ensure proper dispersion of pigment, color con centrates should be prepared by 2-roll milling. This also applies to heat stability tests. Concentrates are best dispersed in Alathon 7040 and reduced into the Alathon 7050. c. BT-297-D showed maximum warpage effect in tint in AlSthon 7050 at 0.25 phr. less warpage was evident at 0.5 phr and 0.1 phr. d. Since TiOa (R-101) contributes considerably to warpage, future tests should be run on masstones rather than tints. e. Use of c p c --Ap on BT-297-D and BT-383-D at best gives only marginal improvement in warpage resistance. C. Paint Applications 1* Tinctorial Properties As (3-CPC grows in plastics and heated solvents and this growth is inhibited by CPC-AF, it would be expected to behave similarly in paint systems, indeed, strength improvement by CPC-AF addition has been demonstrated in high work applications such as ball milling in acrylic lacquer and thermosetting acrylic enamel and CAB 2-roll dispersion in acrylic lacquer, in ball milling, a small particle pigment is subjected to a crystallizing solvent over a 72 hour period. This causes considerable crystal growth to occur in spite of the crushing action of cascading steel balls, in CAB 2-roll mill dispersing, crystallizing conditions occur during "reduction" or dissolution of the CAB chips and possibly in the 2-roll milling itself. CPC-AF also improves flocculation resistance or shear/strength uniformity; it increases the strength of poured paint relative to sprayed paint. An experiment which demonstrates crystal growth of 8-CPC and inhibition by CPC-AF is summarized in Table IV. TABLE IV EFFECT OF CPC-AF QN STRENGTH AND FLOCCULATION RESISTANCE OF BT-383-D Flocculation % CPC-AF When Added Relative Strength Resistance 0- 100 6 15 Initially 93 9 15 After 2 days 98 9 Note that CPC-AF-treated BT-383-D is 7% stronger than the un treated sample. If CPC-AF is added after two days of ball milling, most of this strength is lost. On the other hand, flocculation resistance does not appear to be affected by crystal growth since both materials with 15% CPC-AF have good flocculation behavior. The relationship between strength and % CPC-AF is shown in Table V for ball milling. DUP050081429 7 TABLE V EFFECT OF CPC-AF ON TINTING STRENGTH OF BT-383-D Acrylic Lacquer 72 Hour Ball Milling % CPC-AF 0 5 10 15 20 25 Relative Strength 100 98 95 94 95 96 Evidently, strength increases with greater CPC-AF utilization until its effect is counterbalanced by the lower tinting strength of the CPC-AF itself. Thus, 15% appears to be the optimum con centration of CPC-AF for maximum strength by ball milling. It has also been demonstrated that transparency of BT-383-D and BT-297-D are degraded by CAB chipping or ball milling. CPC-AF improves transparency of both products but the BT-2 97-D-based BT-465-D is more important because BT-297-D has greater transparency BT-383-D. BT-465-D is stronger and more transparency than BT-417-D. Two competitive products in this area are the Harmon's tetrachloro CPC, Phthalo Blue B-4804, and American Cyanamid's Cyan Blue GF 55-3450, a fJ-CPC treated with phthalimidomethyl CPC. The Harmon product has good transparency with a desirable green flop but poor flocculation resistance, viscosity, and gloss (see Appendix D. Check List on BT-465-D) and sells at a considerable premium. The Cyanamid product has excellent strength and working properties but is far short of BT-465-D in transparency. So far, we have been discussing high work dispersion techniques such as ball milling and 2-roll milling. In sand milling, relatively little work is done and the dispersion is prepared over 1/2 hour. This allows very little time for crystal growth. Surprisingly, however, CPC-AF imparts considerable strength to BT-297-D and BT-383-D in both acrylic lacquer and TAB. This phenomena have not been properly investigated but it is believed due to improvement in ease of dispersibility. BT-465-D is more transparent in both sand mill lacquer and enamel than BT-417-D, B-4804, and GTNF-55-3450. However, the latter is more or less equivalent in strength. In general, BT-465-D has superior flocculation resistance to the afore mentioned pigments. 2. Working Properties Aside from crystal growth inhibition, CPC-AF imparts improved gloss and viscosity to both BT-297-D and BT-383-D. An example of this is shown in Table VT. DUP050081430 8 TABLE VI EFFECT OF CPC-AF ON BT-383-D VISCOSITY Ball Mill 72 Hours Acrylic Lacquer #4 Ford Cup % CPC-AF Viscosity in Seconds 0 103 5 90 10 86 15 80 20 77 25 76 Note that at 15-20%, viscosity begins to level off. Gloss is, likewise, improved. In fact, gloss improvement demonstrated with BT-383-D using as little as 1% CPC-AF. Use of CPC-AF with a-CPC for stabilization requires presence of calcium rosinate (Staybelite). In general, most of the effects of CPC-AF on (3-CPC occurred independently of calcium rosinate. How ever, in one case, sand-milled TAE viscosity reduction by CPC-AF was enhanced by calcium rosinate as shown in Table VII. TABLE VII EFFECT OF CALCIUM STAYBELITE - CPC-AF ON BT-383-D VISCOSITY TAE-2 ! '''!" '' l""-: -.. Sand-Milled Brookfield Viscosity 6 12 30 60 CPS Ford Cu p Viscosity BT-383-D 5000 135' BT-383-D + 15% CPC-AF 300 267 200 165 5.1' BT-383-D + 15% CPC-AF 125 100 90 85 34' + 10% CaSx BT-465-D offers far superior viscosity and gloss vs. BT-383-D, BT-297-D, and the competitive B-4804. In general, it is superior to GTNF-55-3450 but inferior to BT-417-D. 3. Humidity Resistance With new automotive industry standards for this property, it is important that all new products designed for auto motive finishes not contain water-soluble materials. F, and F. considers BT-417-D performance in this respect to be acceptable. The original (A) process BT-465-D called for combination of two pigment slurries followed by centerfeed pressing (no washing), It was found that humidity resistance performance was variable, sometimes worse than BT-417-D. This is believed due to variable salt content of the CPC-AF slurry. DUP050081431 -9 - Use of a 5000 ohms wash on a Semi-Works material gave humidity resistance in acrylic lacquer markedly superior to BT-417-D. Thus, the (B) process requires washing to 5000 ohms to ensure good humid ity resistance. Under these conditions, % water soluble matter is reduced to ca. 0.05%. 4* Lightfastnes s Florida exposures to date have run 3-6 months and indicate BT-465-D lightfastness to be more or less equivalent to BT-417-D. In other words, lightfastness may only be marginally acceptable. This lightfastness behavior is due to the small particle size of BT-465-D relative to BT-297-D after crystal growth has occurred. Also, b-phase CPC's appear to have poorer lightfastness than other CPC phases. Appendix D contains detailed lightfastness data. 5. Other Phthalocvanines For patent purposes, other phthalocyanines were treated with 15% CPC-AF and evaluated in TAE. in all cases, some beneficial effect was obtained. The materials evaluated were metal-free, metal-free polychlor, iron, cobalt, nickel, and lead. The lead material showed considerable improvement in strength with consider able blue shift. Except for metal-free components, flocculation resistance was improved dramatically. Viscosity was generally depressed, most dramatically with the metal-free PC. D. Ink Applications Since fluid inks can be likened to paint systems, it is not surprising that strength can be improved and viscosity lowered for codes like BT-383-D. The effect of CPC-AF on BT-383-D is summarized in Table VIII. TABLE VIII EFFECT OF CPC-AF ON BT-383-D PROPERTIES IN NITROCELLULOSE FLUID INK Ball Milled Brookfield Viscosity % CPC-AF Relative Strength 6 ran 60 rom Zahn Cu d 0 100 14,000 3,100 105' 5 100 6,600 1,700 67' 15 98 275 235 13* 25 96 250 230 13' Both BT-383-D and BT-297-D are improved but are inferior in tinctorial and working properties to BT-417-D. In oleoresinous inks, CPC-AF treatment did not improve proper ties of BT-383-D and BT-297-D by 2-roll milling. Evidently, (3-CPC does not grow in these systems. Therefore, CPC-AF with its poor tinting strength only dilutes the 0-CPC. It is also possible that viscosity is not improved because CPC-AF itself is insoluble in low polarity vehicles, therefore, not having a mechanism for dis tribution on the surface. DUP050081432 - 10 - APPENDIX A DETAILS OP THE INVENTION Example I This example illustrates a preferred procedure for prep aration of the additive which when mixed with a beta-phase phthalo cyanine pigment confers to said pigment the properties of resis tance to crystal growth, flocculation resistance, and rheological improvement in paint vehicles as described previously. All parts are by weight unless otherwise indicated. To 6.0 parts of anhydrous cypric chloride in a mortar was added, in portions, with intermittent grinding, 3.0 parts of pyridine, followed by 20.0 parts phthalonitrile. The resulting intimate mixture was heated at 230c. for one hour in an open glass container. The resultant blue cake was cooled, pulverized, and added to a solution of 3.7 parts of concentrated sulfuric acid in 1500 parts of water. The slurry was boiled for one hour, and the product was collected by filtration, and washed substantially free of acid and sulfate ion. The resultant presscake may be combined with a beta-phase phthalocyanine before drying to produce the aforementioned improvements or, alternatively, the presscake may be dried and the dry product mixed with beta-phase phthalo cyanine . If preferred, the additive can be mixed with prime pig ment at the point of use. In place of the copper chloride specified in this example, other copper salts known to give copper phthalocyanine in the wellknown copper phthalocyanine synthesis from phthalonitrile, can also be used satisfactorily. Copper powder may also be used in place of the indicated copper chloride. The ratio of copper salt to phthalonitrile is not critical, but may be varied considerably as is well-known in the art from preparation of copper phthalo cyanine reactions of this type. The proportion of pyridine or other nitrogen base used should be in excess of 0.15 mol per mol of phthalonitrile. Other nitrogen bases can be used in place of pyridine but are not preferred because of the lower cost and ready availability of pyridine. Among the nitrogen bases which function effectively are quinoline, isoquinoline, and picoline. The preferred procedure shows the reaction being carried out in the absence of a diluent, but the reaction can also be carried out in the presence of an inert diluent such as kerosene, trichlorobenzene, and other re action media found useful in the well-known phthalonitrile syn thesis of copper phthalocyanine. In place of the procedure described here, the product may be reduced in particle size by acid pasting, salt milling, or like methods well-known in the art. It is preferred to reduce the particle size before use, but the product is also significantly effective when used in crude form without size reduction. DUP050081433 - IX - APPENDIX B Example II - Stabilization of Beta-Phase Copper Phthalocyanine Against Crystal Growth on Heating in Crystallizing Solvent Crystallizing solvents are defined herein as solvents in which phthalocyninanes have slightly greater solubility as compared to solubility in straight chain aliphatic solvents. ("Phthalocyanine Compounds" by Moser and Thomas, Reinhold Publishing Corp., 1963, page 2$.) Exposure of unstabilized beta phthalocyanine pig ments to such crystallizing solvents results in particle size growth. 100 part of 1-chloronaphthalene was brought to the boil (264C.) in a glass flask. An intimate mixture of 0.75 parts of the dry product of Example I and 4.25 parts of pigmentary betaphase copper phthalocyanine was added to one flask and 4.25 parts of pigmentary beta-phase copper phthalocyanine was added to the other. After heating at the boil for 30 minutes under a reflux condenser, 100 parts of 1-chloronaphthalene at room temperature was added to each flask, bringing the temperature to 170C. The slurries were then filtered separately, the pigments were washed with benzene and dried. Electron micrographs showed the sample containing the material from Example I contained crystallites with an average size of only approximately 0.2 microns, whereas the other sample, which contained none of the material from Example I, contained crystals which were much larger, some exceed ing 2.0 microns in length. Similar results were obtained when the experiment was carried out using kerosene, rather than 1chloronaphthalene, as the heated liquid. In this case also, the sample containing the material from Example I was much smaller in particle size after heating with the crystallizing solvent than was the pigment without the additive from Example I. The larger particle size pigment was much the weaker in each case, as judged by the quantity required to produce a given depth of color when mixed with a white pigment. DUP050081434 'CRYSTAL GROWTH'- |ii ^64* 0 | I ] I CL-NAPHTHALENE DUP050081435