Fused Metal Resinates from AldehydeModified Rosin WILLIAM E. ST. CLAIR, J. C. MINOR, AND RAY V. LAWRENCE Naval Stores Research Division, Bureau of Agricultural and Industrial Chemistry, U . S . Dept. of Agriculture, Olustee, Fla.
M
ETAL resinates have a variety of uses, and the desired
properties vary with the use. In general, however, high metal content, solubility in hydrocarbon solvents, pale color, and rseistance to oxidation are desirable characteristics. These resinates are prepared by three different methods; precipitation process, solvent process, and direct fusion process. The precipitated metal resinates are prepared by a double decomposition reaction between sodium resinate dissolved in water and a water soluble salt of the metal. Metal resinates prepared by precipitation contain approsimately a stoichiometric amount of metal, but they are less soluble and, being finely divided, do not store as well as the fused resinates. The solvent-processed metal resinates are prepared by refluxing a hydrocarbon solution of rosin with a reactive metal compound. This method permits the use of lower reaction temperatures than are required by the fusion process. However, the removal of the solvent necessitates the use of temperatures equal to those required by the direct fusion process. In the fusion process, met'al resinates are prepared by the fusion of rosin with an active metal compound. Usually the acetate, hydroxide, oxide, or basic carbonate of the metal is used. These fused resinates are simpler and less hazardous to prepare than the solvent-processed resinates (1). The fused resinates also have better solubility characteristics, better color, and are more easily stored than the precipitated product'. However, the quantity of metal compounds that can be reacted mit,h rosin by fusion is frequently quit,e low because of the tendency of the resinates of several metals to block ( 1 ) ; that is, they set up into a semicrystalline, infusible mass. Elliott ( 2 ) states the greatest disadvantage of fused resinates has been their low metal cont,ent as compared with other soaps. Palmer and Edelstein (4,5 ) , Borglin and associates ( I ) , and Yiosher (3)found that fused resinates prepared from polymerized rosin and the metal acetate, or from the oxide of the metal in the presence of acetic acid, avoided most of the difficulties of blocking except when a stoichiometric amount of the metal salt was used. Since fundamental investigations conducted in this laboratory on the reactions of resin acids with aldehydes resulted in products that seldom formed crystalline derivatives, it seemed likely that an aldehydemodified rosin would be a good starting material for the preparation of noncrystalline, fused metal resinates ( 7 , 8). In a previous paper ( 6 ) )the preparat,ion of high metal content, fuaed zinc resinates by reaction in the presence of an aldehyde was discussed. This paper describes an extension of this technique to other metal resinates. This process permits the preparation of fused metal resinates that contain a metal concentration equivalent to those of the precipitated metal resinates. There has been no method of preparation previously reported for the resinates of some of these metals. -Most of the fused metal resinates prepared from formaldehyde-modified rosin were completely soluble in the common varnish solvents. The formaldehyde appears to react with each of the resin acids present in the rosin to give several different reaction products. Compared with ordinary rosin, the formaldehydcmodified rosin will react with a much greater proportion of the various metal salts without losing its resinous character. This is attributed to its increased heterogeneity.
Practically all the readily available aldehydes were used in the preparation of metal resinates, and all those used apparently contributed to the nonblocking of the resinates during preparation. Formaldehyde was usually the most effective aldehyde, and most of the work x a s carried out with formaldehyde-modified rosin. All the common forms of formaldehyde were employed in these iiivestigations. Paraformaldehyde and the alcoholic solutions of this aldehyde were its most convenient forms for use a t atmospheric pressure. The aldehyde-modified rosin reacts with the various meta! salts in much the same manner as ordinary rosin. The oxides, hydroxides, carbonates, aud acetates of the divalent nietals apparently form a product containing two molecules of resin acid combined with each atom of the metal. When more than a stoichiometric amount of the metal acetate was used, salts of the mixed acetate-resinate type similar to those described by Borglin ( 1 )were probably formed. Several rosin derivatives that had very low acid numbers were reactedwith formaldehyde and then with a metal acetate. Tables I11 and IV give examples of the products obtained by the reaction of decarboxylated rosin and rosin esters with manganese and cobalt acetate. Similar products h,ave been reported from zinc acetate and decarboxylated rosin (6). Some of the resinates, prepared from these low acid number rosin esters, contained almost 20 times as much nictal as would be expected to react with the free carboxyl groups present. Decarboxylated rosin with an Acid No. of 20 reacted with about 17 times as much manganese acetate as would be required to form a manganese diabietate. The cobalt and manganese derivatives from the decarboxylated rosin and rosin esters were completely soluble in mineral spirits, and the metal was not removed from the mineral spirits solution by washing with water. Solutions of these resina% Fere equal to solutions of commercial fused resinates of the same metal content in their effcct as driers on catalyzing the drying of linseed oil film. PROCEDURE
The following procedures for the preparation of the fused metal resinates were satisfactory in most inatances. The rosin or rosin derivative and the particular aldehyde were mixed together, then without agitating the mxture the temperature was raised to 170' C. over a period of about 1 hour. This waa followed by mechanical agitation and a gradual rise in temperature. While the temperature was raised to 250" to 275' C . the metal compound was added slowly, with sufficient time allowed for the added metal compound to react before another portion. was added. In some instances resinates were prepared by mixing rosin, paraformaldehyde, and the metal m c: ound together and fusing a t temperatures of 250" to 275 The rate of heating had to be carefully regulated to avoid excessive frothing. The addition of 1 to 5y0 parafornialdehyde would cause metal resinates, which had been prepared without an aldehyde, to liquefy after they had hlorked.
8.
Reaction condition8 and propel ties of various resinates from aldehyde-modified rosin are givm in Table I. When the metal used was below hydrogen in the electromotive series, a much lower reaction temperature had to be used. I t was necessary to react the aldehyde with the rosin and then t o
1973
INDUSTRIAL AND ENGINEERING CHEMISTRY
1974
Vol. 46, No. 9
hfET.4L RESINATES FROM R O S I SAND ~ A~LDEHYDE-h'~ODIFIED ROSIN TABLE I. FTXED
Metal Compound Na(C~H30z) Li(CzHaOz).2HzO K(CzH30z) Ca(0H)z
Per 100 P a r t s of Rosin Metal com- Stoichiometric Paraformalde- Maximum Reaction pound, parts a m t . metal hyde, parts by Reaction wt. Temp., OC. Time. Hours b y wt. compound6 5 250 3 24.6 25 260 240 310
3 1.5 3
F I G
26.4
5
3 10
3
R.1
> 170
32.1 32.1 41.0 21.3 24.5 24.5
10 5 5 5 0 5 0
320 290 250 260 280 280 270
2 2 1 6 3 3 3
F I
1225 143 125 151
5 5 5 5
5 0
270 260 300 280 180 270 270 310
3 2 3
15 22.6
12.9 7.2 11.6 26.5 21.2 17.4 17.4 36.8
2 3 2 2
Black Opaque Green Green Blue F Brown Opaque B Blocked
39 16.4 25
36.7 39.6 39.6
3 0 2
250 300 260
3 3 5
H Blocked Blue
41 91 30
39.6 39.6 39.6
5 10 0
275 300 230
4
3 3
34 30 36.2 16. I 16.7
39.6 30 39.8 16.2 16.2
5
5 5 0 5
230 130 200 320 300
4 3 2 1.5 2
Blue Blue Opaque. brown Green Green G Blocked H
>220
16.7
16.2
30
300
2
D
>220
30.6 29.4 11.1
28 16 33.3 42.5 39.6 15 15 11.4 6
10 20 32.8 15
A l ( 0 H ) (CzH30z)z
Softening Point6 (Ring and Ball) of Metal F i n a t e , Solubility in Petroleum C. Naphtha 120 Soluble if 1 % alcohol Dresrnt 115 115 > 170
5 5 5
28 31.1 8
10
XIn(CzHaOz)z4HzO Co(CzK30z)a~4HzO Co (CzH30z)z.4Hz0
Color Grade of Metal Resinate F
...
5
0
4
h-
B Opaque
F
...
128
...
99 93 82 81 111
... 106 ...
141
...
108 148
... ...
127 100 138
...
coho1 present Soluble Soluble Soluble Soluble Heavy ppt. Soluble Heavy black ppt. Soluble Soluble Soluble Soluble Soluble Completely soluble Soluble, no p p t . Incompletely soluhip
Soiiiie Heavy ppt. Soluble, blue solution, no ppt. Soluble Soluble Blackish-brown PPt. Soluble Soluble Soluble Gals and ppt. Soluble if 1% alcohol present Soluble if 1% alcohol present Soluble Heavy white ppt. Soluble
1 95 40 74.6 8 250 G 260 35 38.8 0 3 White ... 250 4 4 F 81 35 38.8 9.5) Soluble 147 8.6, 250 3 Blue 5 20.8J a W W gum rosin Acid No. 168, and a softening point of 7Z3 C. (ring and ball). b Leaders indica;e t h a t property could not be determined. c Softening points prepared with magnesium acetate vary over wide range depending on amount of acetic acid removed and may be lowered by adding some of the acidic distillate back t o t h e reaction mixture. d Titanium chloride (26.5 parts) was refluxed with excess glacial acetic acid t o form a clear solution t h a t was added to the hot aldehyde-modified rosin, resina t e analysis-7.14% titanium. e Small a m o u n t of water was added to the crystalline zirconium acetate t o initiate its reaction with rosin. / Slurried in glacial acetic acid and added as a slurry t o the hot rosin.
lower the reaction temperature below the decomposition temperature of the metal resinate. I n the preparation of copper resinate temperatures in excess of 130" C. caused precipitation of metallic copper. I n the case of some of the less reactive metals it was necessary to use the freshly precipitated hydroxide or to slurry the freshly prepared hydroxide with acetic acid and add this slurry to the fused rosin-aldehyde reaction product. By using one of these procedures a satisfactory metal resinate of all the common metals was prepared. A typical preparation of a metal resinate was carried out as foll0ws : One thousand grams of JTJV gum rosin were added to a 3liter, three-necked, round-bottomed flask. Fifty grams of paraformaldehyde were added and a thermometer, glass stirrer, and a Dean-Stark moisture trap with a water condenser were attached. The temperature of the charge was brought to 170' C. over a period of 1 hour with a type hl: Glas-Col heating mantle and held a t this temperature until the foaming had subsided. The stirrer was started, and the temperature was increased to 250' i 5' C. Then, over a period of 5 hours, 420 grams of cobaltous acetate (tetrahydrate) (Baker's analyzed c. P.) were added in small increments (50 grams) allowing each portion to react before the next portion was added, The temperature was raised to 270' i 5" C. and held there for 2 hours. The cobalt resinate was allowed to cool t o 175" C. and then poured from the flask. The cobalt resinate had a blue color and a softening point of 140" C. (Ring and Ball). The product was soluble in turpentine, linseed oil, mineral spirits, and petroleum naphtha. A higher reaction temperature was required for the hydroxides, oxides, and carbonates of the metals than was required for the acetates.
GENERAL PROPERTIES
The fused metal resinates prepared from the different, aldehydemodified rosins were homogeneous> amorphous resins. The softening points and color grades varied with the amount and type of metal compound, the amount' and type of aldehyde, and the type of rosin or rosin derivative used. The properties of various fused metal resinates prepared from formaldehydemodified J!W gum rosin are shown in Table I. Comparative runs were made with most of the metal salts using ordinary rosin. The aldehyde-modified rosin reacted more readily and permitted the inclusion of more metal in a hydrocarbon-soluble resinate than did t,he ordinary rosin. However, t,he optimum conditions for the preparation of metal resinates from aldehyde-modified rosin and t,he ordinary rosin were scldom identical; and since our comparisons were made under the optimum conditions for t,he aldehyde-modified rosin, most of these comparative runs are not, included. I n Table I1 are shown the properties of fused manganese resinates cont,aining 7.5 to 8% manganese prepared from W W gum rosin and different aldehydes. The manganese resinates prepared from formaldehyde-modified rosin usually had darker color than the manganese resinates prepared from the higher molecular %-eightaldehydes. The resinates of vanadium, molybdenum, and t>ungstoncould not be prepared directly from any of the readily available conipounds of these metals; however, if vanadic acid or the oxides of molybdenum and tungsten xere slurried in acetic acid and this
September 1954
INDUSTRIAL AND ENGINEERING CHEMISTRY
slurry added to the hot rosin-aldehyde product, these metals would combine to give homogeneous metal resinates. If the acetate of a metal were available, a satisfactory fused metal resinate could be prepared from it.
T ~ B L11. E FUSEDMANGANESE RESIii.4TES PREPARED ALDEHYDE-MODIFIED ROSIN
FROM
Per 100 P a r t s of Rosin Softening Aldehyde, Manganese Point (Ring parts b y acetate parts and Ball), hlodifying Agent weight b y wdight Color Grade a C. F 150 41 Aq,ueous formaldehyde F 132 38 Trioxymethylene 40 E' 152 Acetaldehyde D 149 41 Butyraldehyde I 150 41 Benzaldehyde G 151 41 Acetal H 149 41 Methylal
Metal Content. The maximum metal content obtained in a clear, homogeneous, hydrocarbon-soluble metal resinate prepared from aldehyde-modified rosins using a metal oxide, hydroxide, or carbonate was approximately the stoichiometric amount of metal that would react with the free carboxyl groups available to form a metal abietate. When a metal acetate was used the maximum metal content obtained was usually about equal to that required to form a mixed acetate-abietate, Such aldehyde polymers as paraformaldehyde and paraldehyde, which decomposed to give free aldehydes on heating, acted a8 nonblocking modifiers for rosin; whereas aldehyde-free para-n-butyraldehyde, which does not decompose on heating, had no apparent modifying effect on rosin. The addition of a drop of dilute sulfuric acid (mineral acid depolymerizes para-n-butyraldehyde to give free aldehyde) to the blocked reaction mixture of a rosinpara-n-butyraldehyde-metal compound caused the blocked metal resinate to liquefy. After the blocked resinate had become completely fluid, more metal compound was combined with the modified-rosin just as if the rosin had been modified with an aldehyde before the metal compound was added. Solubility. -411 of the metal resinates showed good solubility in petroleum naphtha, mineral spirits, linseed oil, and turpentine. Most of the metal resinates were soluble in mineral spirits in concentrations up to 40 to 60% solids. The neutral resinates of aluminum and calcium were soluble in the hydrocarbon solvents; however, a t metal concentrations approaching a stoichiometric quantity of these metals, the solutions would gel1 on standing. The addition of a little alcohol to the solvent usually prevented gelling. Fused cobalt resinates ordinarily contain about 2 to 2.5% cobalt. The product made with no formaldehyde contained 3.5% cobalt and was not completely soluble in mineral spirits. The cobalt resinates prepared from rosin that had been reacted with 5 parts formaldehyde per 100 parts of rosin reacted with 41 parts of cobalt acetate. Forty-five parts of cobalt acetate tetrahydrate should react with 100 parts of rosin having an Acid No. of 168 to form cobalt diabietate. Forty-one parts of cobalt acetate tetrahydrate per 100 parts rosin gave a resinate containing 8.9% cobalt. By increasing the amount of paraformaldehyde to 10 parts per 100 parts of rosin, the amount of cobalt acetate tetrahydrate that could be added without blocking could be more than doubled; however, this does not double the cobalt content. The product prepared with 91 parts of cobalt acetate tetrahydrate per 100 parts of rosin contained 14% cobalt. This is just about the theoretical cobalt content for a cobalt acetate abietate. Since rosin is a very good reducing agent a t the temperatures used in carrying out these reactions, there was a tendency for cobalt resinates that contained more than 10% cobalt to decompose to form some cobalt metal on prolonged heating. Lead resinates prepared from litharge and rosin usually give mineral spirits solutions that form heavy sludges on standing.
1975
The use of aldehyde-modified rosin gave only a slight decrease in the amount of sludge formed. The mixed cobalt-lead resinate shown in Table I contained approximately 2% cobalt and 20% lead with enough acetic acid present to form a mixed acetate abietate. This product was completely soluble in mineral spirits containing 1% alcohol and showed no appreciable amount of sludge formation on standing for 2 weeks. The preparation of manganese resinates is quite similar to the preparation of cobalt resinates. Ordinarily, fused manganese resinates contain about 3.5% manganese. By using an aldehydemodified rosin the manganese content was increased up to s%,and the resinate formed was completely soluble in mineral spirits. Mineral spirits solutions with a viscosity of D (Gardner-Holt) containing 5% manganese were prepared from aldehyde-modified manganese resinates. Some of these solutions stood for more than a year without showing any sludge formation. I n Table I1 is shown a variety of aldehydes used Kith manganese to prevent blocking. Practically all the aldehydes tried (about 2 5 ) gave some improvement in the processing and in the solubility of the finished product. I n a few cases some of the higher aldehydes appeared to form a little better metal resinate than when formaldehyde was used; but considering the greater reactivity of the formaldehyde and its lower molecular weight, it is doubtful whether any of the other aldehydes would be as practical. Aluminum basic acetate reacted readily with the aldehydemodified rosin. However, the softening points and viscosities of the aluminum resinates are so high (well above 220' C.) that the processing temperatures had t o be a t least 300" C. These aluminum resinates were completely soluble in hydrocarbons, but the solutions (unless stabilized) set in a very firm gel. Mineral spirits solutions of these high melting resinates containing 50% solids when stabilized by the addition of about 1% alcohol had a viscosity of D on the Gardner-Holt scale. Some examples of aluminum resinates prepared from basic aluminum acetate and aldehyde-modified rosin are given in Table I.
TABLE111. MANGAKESE RESIKATES FROM ROSINDERIVATIVES (Reaction conditions 240' to 260' C. for 2-4 hours; all products dissolved in mineral spirits to give clear solutions)
=,Five parts of paraformaldehyde reacted with each 100 parts of rosin derivative.
Several rosin derivatives that were essentially neutral were reacted with formaldehyde and then with manganese acetate. The amount of manganese acetate that combined with these neutral derivatives appeared to be equal to and sometimes greater than the amount that reacted with the rosin. I n Table I11 is shown the amount of manganese acetate that reacted Tvith samples of rosin oil and rosin esters having acid numbers from 5 to 5 5 . Over 17 times as much manganese reacted with a dccarboxylated rosin having an Acid S o . of 20 as can be accounted for by the carboxyl groups present. The manganese derivative formed is completely soluble in mineral spirits, and the manganese was not extracted from a mineral spirits solution with water. The acetates of cobalt, lead, and zinc reacted in a similar manner. The acetates were the only salts that reacted in this manner; the hydroxides, carbonates, formates of the metals reacted only with the rosin acid present and showed no appreciable reaction with the neutral portion.
1976
INDUSTRIAL AND ENGINEERING CHEMISTRY
Table TV shows a similar group of cobalt compounds prepared by the reaction of a neutral rosin derivative, formaldehyde, and cobalt acetate. The cobalt acetate reacted as readily as the manganese acetate. I n order to deterniine whether the cobalt derivatives of decarboxylated rosin could serve as driers, a slow drying varnish was prepared by heating 1000 grams of refined, unbodied linseed oil and 250 grams of 11-\V rosin a t 270" C. for 1 hour. This varnish was dividrcl into 3 portions of 375 grams each. To one portion was added 38 granis of cobalt resinatc, (containing 0.840 gram of rohalt) dissolved in 37 grams of mineral spirita. This cobalt, resinate was prcpiired by fusing IVK gum rosin and cobalt acetate a t 260" to 275" C. for 4 hours. To another portion of the varnish m ~ i dadded 10.5 grams of cobalt resina,te (containing 0.840 gram cohalt) froin rosin oil dissolved in 8.5 grams of mineral spirits.. This rohalt resinate ITas the product described in Table 11-p r q : ~ r e dfrom the rosin oil viit,h an .4cid S o . of 55. I n order to equal e resin concentration of the two solutions 27.5 grams of rosin dissolved in 26.: grams of mineral spirits KLIS also a d t l c d to this portion. ( S o metal compound other tliari c.olx!t WAS added to these varnisheh.) To the ehird portion of vwriish, ir-hirh served as a blank, was added a solution of 38 gi.i:rnc of lY\Y i,o.iri dissolved in 37 grams or mineral spirits.
(Reaction conditions 250-200O C. for 2-4 hours: all pi.oducts dissolved in mineral spirits t o give clear blue solutions. cuhalt is riot extracted by nasliirinr the rnineral spirits so1i:iion \vitli \rater) Sloicliioinetrir Parts Amount Cobalt C'ohalt .icetatei100 Pal t 4 .-lrctate Softening Point of Rosin Deli\-aActually (Ring and Ball), Rosin Derivative tive' Related c. Rosin oil 4 4 51 Liquid Acid No. 20 Rosin oil -k 1 140 12 2 Acid h-o. 55 1 1 41 Liquid Methyl abietate Acid No. 5 41 141 Ester gum 3 3 .4cid No. 15 a F i r e parts of paraforrnaldPhydc per 100 parts of rosin derivative.
Films of these varnishe,? x e r e p i , c y i ~on ~ I 31/1 X 4 inch glass plates. These plates were allon-eti io (11,~-in a dust-free cabinet. The rate of drying was determined h y measuring the hardness of the films a t suitable inter~-alswifh a Bn-srd Hardness Rocker. There was no appreciable diflerenw in the drying rate of the films catalyzed with the t n o diffcrent typrs of c-ohalt resinates. Tlic results of these tests are shown in Table V,
TABLE 7'.
Vol. 46, No. 9
D R Y ~ SRATES G O B V.4RNISH FIL.\.IS ALDERYDE-MODIFIEI) COBALTRESIXATE FROM ORDIIK~RY ROSS
COMPARISON O F
CAT.ALYZED WITH COBALT RESIS.4TE FROM
ROSINOIL A N D
Lhyinz Time, Hours 20
sa -_
1-10 312
_ _ ____ Ilardness'J ~ ~~ of - Varnish . _ _ I'ilm_ Cohalt-rosin oil Cobalt-rosin drierb drier C Blank-nu 0 6 0
64
12 14 16
1i 14 1 li 18
~~~~
ilri:,r
!
720 1080 18 lleasiired bv Sward Hardness Rocker 5 Prepared as described in second sariiple of (Rosiri Oil A.N. 5 5 ) Table IY: 0.810 grains of cobalt/450 grams varnish. C Prepared by fusing TK g u m rosin and cobalt acetate a t 2fi0° t o 275' C . for 4 hours: 38 grama of this cobnit resinate containing 0.840 gram cobalt was used f o r 360 grains of 1-arnish ~
~~~
~
CONCLUSIONS
A simplch method of preparing h e e d metal resinates thai. rom tain approsiniiitely a stoichiometric quantity of metal has heeii dweloped by modifyirig rosin with an aldehyde and fusing this aldehyde-modified rosin with a reactive metal compound. Lletal resinates prepared from aldehyde-modified rosins do not block and ahorr- good solubility in petroleurn naphtha, turpentine. and mineral spirits. Metal yesinate? of all the common metn!s have been preparcd lroni aldehyde-modified rosins. Metal resinates may be prepared from nldehyde-modified rosin derivntivei that have an Acid 1-0. ol les:. than 20. LITER.4TURE CITED
I3orgliri. d . S . , Nosher, I-'. R., and Elliott, H. A , , IND.ENG. CHEM., 36, 752-6 (1941). Elliott, S. B., "The Alkaline Earth and Heavy Metal Soaps," y.
37, Reinhold Publishing Co., Kea- York. 1936.
Masher, P. R. (to Hercules Powder Co.), U. S. Patent 2,431,191 (YOY.18. 1947).
349--,5l (1952). St. Clair, W. E., and Lawrence, R.V. (to Secretary of Agriculture), U. S.Patent 2,567,250 (September 1961). Ibid.. 2,572,071 (October 1951). RECEIYED f o r review September 10. 1053. ACCEPTED May 24, I D 2 Presented a t the 123rd Mecting of the A U B R I C A CHEMICAL X SOCIETY,Lou AngPIes, Caiif. Kava1 Stores Station is onc of the laboratories of the Bureau of Agricultural and Industrial Chemistry. Agricultural Research Administration, Cnited States Department of Agriculture. The mention of trade names does not indicate a n endorsement by the United States Departrnmt of Agriculture over si~iiilarproducts not mentioned.
