Document 44kXg5V6MdxZZngkLB7B7aOx1

E. I. DU PONT DE NEMOURS & COMPANY KREBS PIGMENTS DEPARTMENT 256 VANDERPOOL STREET NEWARK. NEW JERSEY Copy No. i NEWARK PLANT PIGMENT COLOR RESEARCH REPORT IOW EXCHANGE RESINSi APPLICATION TO COLORED PIGMENTS Period Covered: December 1, 194-5 to February 20, 1946 FILE: DATE: 1/14/4? NJS27S N41560 Copy tot #1 Humerieal File 2 - Research Office (103) 3 Library File (103) 4 - laprial Chemical Industries, Ltd. 5 * * ^M #1 II II ? * W. F. Speagassaa, Newark i Extra 9- - Serial He. KN-46SS8 Copy He. i NEWARK PUIR FIGMENT COLOR RESEARCH REPORT Final Report Titles ION EXCHANGE RESINS* APPLICATION TO COLORED PIGMENTS Period Cererods December 1, 194$ to February 20, 1946 SUBMITTED BY* Maximo Mao Keagie J. 0. Morrison UM****APPROVED BY J.fO. Morrison 1 DATE SUBMITTED* August 22, 1946 DATE ISSUED* 1/14/47 N41560.01 DUP050150662 Application of synthetic lea eackange rosins baa constantly expanded since their introduction in 1935 by Adana and Hainan (1) The unique properties of ion exchange reelne, euch an permitting efficient exchange of out ion for another without the necessity for forming a precipitate with subsequent filtration, or, in the cane of particular reslme, allowing adsorption of entire molecules, have led to constantly expanding use of those materials* The rooine have been applied to such problems as* preparation of colloidal dispersions (witheot peptisatien and dialysis)* recovery of valuable elements from waste solutions, as'in the recovery of copper fro* plating solutions! purification of sugar solutions and other edible oonpositisttS! removal of unwanted salts from various chemical systems! and various separation processes and analytical procedures* An investigation of ion exchange rooine was undertaken with the intent of developing possible applications to the pigment industry* This report presents the program of study drama op as the result of a literature survey, and briefly diseuscea the very limited experimental program carried out to data* The investigation of ion-exchange resin* and of possible applications of those materials to colored plgcents was Initiated with a survey of the available literature* hue to interruption of the pregram at aa early date by another problem, quantitative experimental work was very limited* This consisted primarily of study of several comparatively salt-free sola* a fee experiments on flocculating lr#n blues and a molybdenum blue eelleid were alee conducted* He positive leads were developed but further study is recommended. QISCUSSIQH Wvfrmlm ftlgiLiASteasii * lonle exchange is usually defined as the Interchange of ions between a liquid phase rad a solid, resulting in no radical change in the structure of the solid* (Several eaeee of exchange between two solids in aqueous suspensions have also been reported*) Ionic exchange era bo of the following types* things 1* Salt exchange in which one metallic or organic cation is replaced by another* Ga**asS 2Na%GaS li _g.atiea Exchanger 1 2* Hydrogen eyole in which metallic or organic cations are replaced by hydrogen ions* 2Na*+H8g gH*+Kass2 DUP050150663 1* Irw Anion Exchange* 80#a<a^aO 01 301% (RaNH)s 80* 2* Acid removal by addition. (RsH free anion exchanger*) BS1(M (RsM)Gl loa exchangers, frequently, show marked selectivity dilb io controlled by snob factore as elootrie charge, si**, and concentration. The original program of the present investigation included proposed study of the following applications of lea exchange resins* X. Preparation of eelloidaX dispersions of various exidea, such at oiXieen dioxide, aluminum oxide, and titanium oxide, by ion exchange methods and study of thess sols as possible lake-formers or precipitant for various? dyes* Through iasoXubiXisatioa of the dyes, by addition of eelloidaX dispersions, it ms hoped that pijpuenta of unique properties, e*g* high strength, could be prepared* r 2* Preparation of a pigment-type ebreaduu (XXX) oxide through use of the resine* The present commercial method of preparing pigment-grade chromium (XXX) oxide is a rather expensive procedure involving, first, calcination of a mixture of a chromate or dichromic with boric mold or a phosphate, quenching the fused mass in hot cater, grinding, sad washing* Although the more intense forms of the plgpeat are believed to bo hydratod oxides, the desired pigment properties are not Obtained by direct precipitation of the hydrous oxide from chromic salt solutions* The difficulty of obtaining the desired product by precipitation methods may bs associated with the fast that precipitated materials often contain a considerable quantity of foreign lone, whoso removal if very difficult* It should bo possible to prepare hydrated chromic oxide with only infinitesimal amounts ef inpuritioo by the ion exchange method* Xt was proposed to study the pigment properties of sueh material* 3* Recovery ef valuable elements from waste solutions and evaluation ef the coots ef recovery* Concentration ef dilute solutions ef electrolytes has been effooted through the use ef ion exchange resine in many cases* 4* Treatment of pigments with hydrous oxide eels prepared through the use of ion exchange resine* Certain pigments are treated with various oxides, formed by precipitation in the presence of the pigment* Use of colloidal dispersions of the oxides for those treatments should be investigated* 5* Preparation of molybdenum blue precipitates by treating negatively charged molybdsmusp blue eels with positively charged hydroxide eols of metals like Al, fe, Cr, Th, Sr, and Co* Preparation ef both typos of eols normally involves DUP050150664 dialysis* Ira exchange procedures, if applicative, would eliminate the timeconsuming dialytic methcdn, and alee result* presumably* in "purer" sols which sight have improved pigment properties* Also* it was proposed to study direot preparation and simultaneous purification of the above sols by ion exchange methods* some eueeese along these lines having been reported by J* V, Kysnar (2)* 4* Removal of excess salts from iron blue pigments through application of ioa exchange procedures. 7* Improvement ef sine yellow for use in mstalprotective primers* Removal of the undesirable ions (eg* chloride, sulfate) might be offseted through purification of the ingredients used in certain sine yellow processes or possibly through incopporttian of a minute amount of an ion exchange resin into the tine yellow* 6* Preparation ef a silica sol* comparatively free of salts* by ass ef ion exchange resins* Soma work has been dona along those lines by Rysnar (2). He prepared a silica sol of pH (4*0 - 4*3) which is near the 4*8 pH of the very pure sol formed by hydrolysing silicon tetrachloride* The colloidal solution was made from sodium silicate and eulfurie add* The salts were removed by passing the solution through a oetijn*exehenger and than an anion-exchanger resin* This salt-free silica sol might be applied to various pigments (e*g* phoepho-tungstie or phospho-molybdic types) with the expectation of possible improvement in lightfastness* and* perhaps* variation of the particle else and sur face ef the pigments* Seme trouble has been had occasionally with pigments absorbing moisture too readily during storage* It is proposed that a small amount of salt-free silica be incorporated into such pigments* The moisture might then be adsorbed specifically by the eiliea* rather than by the pigment as a whole and the dispersing properties might be favorably altered* Four resins were chosen for laboratory uses De-Acidit (anion exchanger) ami Zee-Karb-H (hydrogen oycls-catioa exchanger) both obtained from Feroutit Company* 330 West 42nd St.* Hew York* also Amberlit IR-IOO-H, (cation exchanger)* and Amberllte 1R-4 (anion exchanger)* obtained from The Resinous Products and Chemical Company* Washington Square* Philadelphia* The Duelite resins wars not used} available Information (3) indicated that they might have slightly different characteristics than the four listed above* Sufficient time was not allowed for study ef variables affecting the stability of sols prepared by intimately mixing a given salt solution with the proper resin and then decanting the sol from the solid rosin particles* The sols that wore stable when prepared by band agitation of the salt solution with resins (on a email seals) wore not stable when prepared in larger amounts and stirred more thoroughly and over a longer period of time* The use of these unstable solutions as flocculating or treating agents for soluble dyes or pigments is not a valid test of the effectiveness of cosparatively salt-free sole* for* upon precipitation* the charge on the colloidal sol particles is diminished and their floooulating capacity is correspondingly decreased* This DUP050150665 limitation must be considered la interpreting the experimental results which, briefly, were as fellows* (1) Dilute solutions of aluminum chloride, aluminum sulfate, chromium chloride, chromium sulfate, titanyl sulfate, cobalt chloride, nickeleus chloride, niekeloue sulfate, and copper chloride were treated with De-Aeidite in attempts to prepare sole ef the respective exides, Analyses ef the reeulting solutions shoved a substantial removal ef the anions* (2) Sols ef aluminum oxide vere prepared by removing the aniens from solutions of aluminum sulfate or aluminum chloride by use of the anion exchanger, Amberlite IR-4-B, These sols vers used, in attempts to precipitate Peaeedk Blue Lake BL|2*D, normally manufactured by^srCSosol Brilliant Blue s Dye on alumina hydrato (prepared from aluminum sulfate and sodium carbonate) Tory little pre cipitation occurred when the eels of aluminum oxide were added to the Blue* It has not yet been determined whether the unsatisfactorily slight precipitation was due to the relative Instability ef the sol or to possible similarity of electrical charges ef the dye and sol* (3) Treatment of a chrome yellow with aluminum oxide sols of the above type gave no improvement in pigment properties ever the standard Chrome yellows, (Instability ef sols may be the cause of negative results), (4) Settling rates of iron blue slurry treated with aluminum oxide eol (aluminum sulfate Amberlite (XR-4-B) shoved no improvement ever thofe of untreated blue slurry (stability ef sols possibly at fault), A fairly arable sol was prepared from copper aoetate in a like fashion. This eol apparently did increase the initial settling rate of tho iron blue slurry, (5) A sol prepared from aluminum chloride and Amberlite IR-4-B flocculated a molybdenum blue sol, wKmmra .w n l n n l (1) Data needed for successful preparation of sols must be obtained experimentally! there is very little of this information in the literature. The variables (time of agitation ef the solution with the resin, temperature, con centration of solution, ratio of salt to resin) must be studied for each saltf all are critical variables in solftrmatien, Ths extent of hydration of tho resins must be known in order to establish the ratio of salt te "active* resin, (2) The balance of the program as originally outlined (Page 2) should be investigated, (3) Study of the flocculating action of aluminum oxide sols/(4) and hydrous ferrie oxide en iron blues (5) might be of value, (4) Most pigments must be washed free of salts before being dried. Therefore, use of salt-free sole would be advantageous, the washing step being decreased or eliminated when the sols are used as floseulating or treating agents for pigments, (e,g, in the preparation of the blue lake BL-f2-D), DUP050150666 (5) The use of the reels* should be studied to obtain the highest exchanger capacity (4) (7) cuad the fastest exohaage conditions. (6) Processes in which ion exchange seeurs between tho solids in suspension (8) (f) ere of intorost. (7) Preparation of s sol of an exchange resin that would retain its exchange properties into* sol stats. (6) Organosols of pigments night he Bade and flushed directly into organic vehioleaj These sols could he prepared through ioa*exehang* (employing the slight amount of eater that is required for the ion exchange) or by other methods. In tho course of the ion exchange program, tho Importance of true colloidal solutions in tho pigment field became quite apparent. 0oilolds, because of tho aetive charge on the eelleidal particles, should logically be more powerful lakeformers than salt solutions. Wider investigation of tho use of true colloids in pigments should be encouraged (16). ttafo.fwwwy, Numerous patents on ion exchange processes have been issuedg there appears to be a constant increase in their number* A patent application by Rohm and Haas (Bfit. Appl. 22585, Nov. 15, 1944) outlines a process for acidifying certain silicates (which form gels in acid medium) without destroying the gel structure of those materials. A slurry of the silieatos is mixed with a cation exchanger (hydrogen cycle)5 separation is effectid by mechanical means* By analogy it might be possible to remove acid from pigment slurries by using an anion exchanger (e*g Do Aoidite), thue retaining the structure of the gele which is often destroyed by ordinary neutral!sation. IMBligWi See Notebook 1183. BBffEBSHOSSg Reference (12), below, presents * comprehensive (209 page) compilation of abstracts of literature covering scientific and industrial application of io*exehange materials. This was published subsequent to termination of tho study reported herein. 1. Adams 3. A. and Holmes, S. Leighton,Adsorption Properties of Synthetic Resins, j. See* Chseu Ind. X-6T, 1935. 2. J* V. Rysmer, Ind. Sag. Ohm. 821, 1944 3. 0* 8* Moore, Jr. (Industrial Engineering Division), loiter to 0. V. Beleh, Jam. 23, 1944. 4. H. B Welser, The Hydrous Oxidee. 5* Holtsaaan, Ind* and Eng. Ohem*, ol. 37, P* 854, September, 1945. DUP050150667 mfom 6* 0* 8* Patent 2,3?6, 924) Eeelite Hegeaeration* t* British Patent* 573* 814, Modification of the Relative Concentration of Cations In Fluid Media* 8* British Patent Application, 16598, Treatment of gel-forming hydrous silieates* 9* British Patent Application, 22565* Stahls, gelling, acidic hydrous silicates* *N 10* Hydrous Oxides by Its Exchange feehalgnes* ISP -46-185, H* H* Stork, Experimental Station, DuPont. (Page 4#) 11* ionic Exchange, (Memorandum to Hr* P* L. Salxberg from Herman 6* Fisher, and Martha M* Dnffey), Experimental Station, October 5* 1945, DuPont. 12* Ionic Exchange, L*8*X* 1683, Martha Duffey, Ohcn* Dept* igxperiae&tal Station, DuPont, May 1946* DUP050150668