Adhesives for Fungicide Dusts E. L. GREEN‘ Agricultural Research A d m i n i s t r a t i o n , U . S . D e p a r t m e n t of Agriculture, Beltsville, M d .
T h e apparatus described is for laboratory-scale tests on small test objects such as potted plants or small glass plates. The fungicidesulfur i n the tests described-is fed into a small rotary blower. Water equal to four times the weight of the solid is added as a spray to the air stream as it leaves the machine. Glass microscope slides were used as test objects because they could be weighed to measure the deposits as first laid down and after exposure to artificial rains applied by an apparatus described herein. Materials to be tested were dispersed in the water used to moisten the dust. Only a few of the one hundred tested caused a desirably increased adherence of the sulfur. Surface-active agents (including detergents) in general were disappointing.
I
N T H E usual methods of applying pest-control materials as
sprays to fruit trees, the quantities of water that are required are burdensome. These requirements can be largely avoided if the materials are applied dry in a blast of air; but this alternative, which has been called dusting, has not given the desired protection as dependably as spraying. Some refinement that would improve the effect has been sought for years. While the resulting effectiveness may still be less than in spraying, usually it has been better when the dust was applied to moist foliage, especially foliage moistened with dew. A further step is to liberate enough liquid water into the air-blast so that the effect of dew could be expected even if no dew was formed naturally. Several machines are already on the market that embody this principle. Another step is to provide as an ingredient, either of the dust or of the water, a substance that would improve the tenacity (adherence or resistance to weathering and rubbing off) of dust. Many attempts have been made to find a material that would have this effect in the usual spray operation, but so far with only moderate success (6). Recently, work has been reported ( 1 ) along the same lines as that proposed here. I n 1947 an attempt was made a t this station to work out a field test of materials prepared for use as adhesives in mist dusting (6). I n this work small peach trees were treated with sulfur dust and the leaves were analyzed for sulfur a t intervals, but it was found that many trees were required for each test in order to compensate for great fluctuations in the sulfur content of the leaf samples. Actually about 300 trees were used t o test only 3 materials. This type of test bears a reassuring resemblance to the field operation, but the amount of trees available for such trials severely limits the number of materials that could be examined. Already the number of materials offered in advertisements is great enough to require many more tests per year than could be done in this way. Accordingly, the construction of a small-scale mist duster was undertaken. Figure 1 shows it as it was used for the tests reported in this paper. The motor and blower of a household vacuum cleaner mounted with the axis of rotation vertical furnished the air blast. Sulfur was the only dust used in these tests, but others could be used as readily. It was taken from a single lot of “dusting sulfur,’’ a commercial product, defined by its name, composed of technically pure sulfur to which has been added about 1% of 1 Present address, Production and Marketing Administration, U. S. Department of Agriculture, Washington 25, D. C.
324
magnesium carbonate to improve the flowing and pouring characteristics. It is described as “more than 95% passing 325 mesh” but the mode of the size range of the particles appeared to be between 5 and l o p in diameter. The product used seemed to be representative of current trade practice as made by a number of companies. The sulfur was held above the blower in a hopper of sheet aluminum in the shape of an inverted pyramid and fed out by the rotation of a mire-bound spiral brush whose bristles passed across a slot 3 X 27 mm. in a replaceable plate that formed the bottom of the hopper. The size of the slot was arrived a t by trial and a different size would probably be required to obtain a suitable rate of feed for another dust material. The hopper was supported by a sheet metal structure shaped like it that fitted i t closely enough to stop air leaks into the intake port of the blower. A phonograph turntable motor drove the spiral brush through a sleeve coupling that could be released by taking out a set-screw. Then the hopper could be lifted out so that it could be weighed for a determination of the rate of feed or cleaned of impacted sulfur. These arrangements are shown in Figure 1 in the view which shows the sulfur hopper viewed from above with the spiral brush inside and in the view of the machine from the back, showing the mounting of the turntable motor. All who have worked with finely-ground sulfur have experienced difficulty in providing uniform rates of delivery from a reservoir or hopper. The present study was no exception and the feed device required unremitting attention. It was strongly affected by the depth of sulfur over the brush, and if a “hole” developed so that air could reach the brush the rate would increase several fold. Because of the strong tendency of sulfur to pack and bridge over above the brush no great depth could be permitted. Also the tendency for holes todevelop precluded a very shallow covering of the brush. Thus, until a miniature feeder as trustworthy as that of Glaves (S) can be supplied it is required that the operator maintain a layer between 2 and 3 inches (50 to 75 mm.) deep over the brush, stir gently now and then to prevent the formation of holes, and a t frequent intervals sift sulfur into the hopper to replace that expended. With these precautions a rate of 1.8 grams of sulfur per second was maintained during several trials, or one fourth of the weight of water delivered. The addition of water to the air blast presented certain problems not heretofore adequately solved. It was required that no distortion, as by a “wind shadow” or strong lateral blast, should occur in the relatively feeble air blast, that the size of the drops be as uniform and as small as possible, and that the process of distributing them uniformly through the cross section of the blast be completed in the least possible distance as measured along the axis of the blast. It was believed that, at the desired rate of delivery, these requirements would not be met by any available nozzle that operated by direct pressure upon the liquid alone, and that nozzles of the atomizer type, in which a jet of air was also used, would serve better. A cluster of a sufficient number of small nasal atomizer nozzles was an obvious device for this purpose. The nozzles used were from metal nasal atomizers No, 15 made by The De Vilbiss Company (Toledo, Ohio). Concentric ring manifolds for compressed air and for water were made of 0.25-inch (6mm.) seamless copper tubing and connected by soldering to the respective air and water supply tubes of four of these nozzles; upon trial this nuni-
February 1950
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Back View, Manner of M o u n t i n g Phonograph Turntable Motor
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Discharge Side, Arran ernent of Liquid Dispensing system
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had to be confined. For this purpose a cabinet 8 X 4 X 6 feet (90 X 120 X 180 em.) was built of Masonite Prestwood on a wtoden frame. A 12 X 12 inch (30 X 30 em.) opening was made in the center of one end, and half of one of the larger sides was removable. A shelf was fastened outside and below thc opening in the end so that when the mist-duster assembly was centered on this shelf the blower discharge port would be at thr center of the window. Figure 3 shows the dusting chamber wit,li the mist duster in position for operation. h closure of 0.125inch (3-mm.) Prestwood was provided for the opening with u truncated cone of metal centered in it. The smaller end of this c'one just touched the mist duster as a 2-inch (5-em.) ring about the 1.25-inch (3-em.) discharge port. The larger 8-inch (20-cm.) end of the cone projected 1 inch (2.5 em.) into the dusting chamI)W.
Figure 2. Dusting Chamber Loolting through Open Door toward Blower; Rack of Slides Is Shown in Position
her was found to be rnough. Unavoidubly the supply tubes approached the dust stream at a right angle to its axis, but the ntoinizer tips were turned to make an acute angle mith it. They cast no wind shadow because they were placed just outside the tiir blast; and as they were symmetrically disposed about it, there vas no noticeable distortion of the dust stream. The arrangement of t,he nozzles with respect to the air outlet of the blower can be seen in Figure 1viewed from the discharge side. A suitable air pressure f t r these atomizers was found to be 18 pounds per square inch (930 mm. of mercury) which was obtained through a reducing valve inserted into the compressed air supply line. -4second prcssure regulator was ernploged to reduce further the pressure to about l pound per square inch (30 to 50 mm. of mercury) in the closed jar that contained the liquid to be sprayed. The tube through which the pressure was applied and that through which the liquid was delivered were each attached through the quarter-turn cover of the jar. Thus a simple quarter turn would open t,he jar for replaeenient or refilling. (Water was run through the system as a rinse between tests.) An average of several trials gave 7.2 grams of izater per second for the output of the four nozzles. The solenoid air valve appears in the foi,eground of the first view in Figure 1; the liquid is controlled by the operation of the solenoid valve shown a t the right in the last view. The first of the pressureregulating valves is shown attached to the outlet of the service compressed air line in Figure 2, the second is at the left in the first view in Figure 1. The phonograph turntable motor met the requirement of quickly attaining a constant and reproducible speed when the current was turned on. Similarly, to attain the runuing conditions with little loss of time, a solenoid-operated valve was placed on the air line where it ix-ould control bot,h the air pressure for the atomizer nozzles and that for the liquid. -4nother was placed in the liquid line between the jar or reservoir and the nozzles. The electrical system was divided so that one switch controlled the air blast, another the dust-feed mechanism, and a third the liquid-dispensing apparatus. The mounting of these switches is shown at the right in the view of the control side in Figure 1. All this apparatus was mounted on a 18 X 18 inch (40 X 40 em.) plywood base for convenience in moving, cleaning, and servicing. As the operation was first planned, it was intended a t least occasionally to dust small trees or other plants growing in pots. The-plants would be stored nearby, hence the dusting operation
To mnove the excess air blown into the closed chamber by thc opei.ation the intake or suct,ion side of the blower was eonneetetl to the interior of the cabinet through a 3-inch (7.5-em.) duct of sheet copper (downspouting). In all probability there was an excess of air during operation that vented itself by escaping through leaks in the cabir:et, becausc the con,-tructim around thc suction side of the blovivcr was ol)viously not perfectly tight, a r i d the atomizer nozzles added a considerhlc amount of air to tho blast. The leaks apparently were small enough that the tlust was filtered out, of the escaping air since no dust was observed. The seams of the cabinet were caulked with builders' caulking compound. After some testing the intake end was located in thc centerline of the fart>herend wall, about 15 . inches (40 em.) from the top, with the pipe pointing upward. As far as the test.. made could indicate, this location gave the minimum distortion of the dust cone. Because of its design the blower was found t o swing the axis of the cone of the blrist about 10" to 15' to thc left of the axis of the discharge port. Test objects were accordingly displaced to the left also. The test objects of the work to be reported were glass miciuscope slides. They were held in spring clothespins fastened >it, 1.5-inch (3.8-em.) intervals t>opieces of wood "4 X Z5/8 inches (18 X 65 mm.) in cross section. These racks were provided a t the ends with metal tabs with "buttonholes" so that they could be hung a t chosen positions in t.he cabinet h y slipping the nitttal tabs over the heads of partially driven screws. These tabs wcrc also used to hang the racks over a hot plate to dry.
Figure 3.
Dusting Chamber Ready for Operation with Mist Duster in Position
Pipe for returning air from interior of chamber t o blower is shown. Air pressure service line is connected by hose t o solenoid valve; t h e pressure regulator is for t h e second, or low pressure, supply
INDUSTRIAL AND ENGINEERING CHEMISTRY
February 1950
327
TESTED IN EXPERIMENTAL MIST DUSTER TABLE I. MATERIALS Code No. Adhesive Products Corp., New York 60, N. Y . No. 5-8461 101 lo2 No. 5-8462 No. 5-8463 103 Advance Solvents & Chemical Corp., New York 16, N. Y. 201 Vistac No. 1 Vistac No. 4 202 American Colloid Co., Chicago 10, 111. S P V Volclay bentonite 301 P a n t h e r Creek bentonite 302 American Resinous Chemicals Corp., Peabody, Mas% 401 u2-8 solids 539-108 402 403 727-10 40% 554-11C 46.5% 404 747-36 27.2% 405 555-40A 43% 406 407 700-25A 44’iY 40R 493-49B ... - . ~ 4 2 : 5 d 409 834-24-1 50:0% 834-15-4 50.0% 410 850-39 47.570 411 Polyco 101 55% 412 Polyco 144 413 Polyco 178 414 Polyco 179 415 Polyco 200 30% 416 Armour & Co., Glue Div., Chicago 9, Ill. Armom Sticker 50 1 Armour & Co., Chemical Div., Chicago 9, Ill. K-242 Soap Emulsifier 601 Atlas Powder Co., Wilmington 99, Del. NNO 701 The Borden Company, Chemical Div., S e w York 17, N. Y . -4-7-M-L casein 801 California Spray-Chemjcal Corp., Richmond, Calif. Orthex Liquid Adhesive 901 Orthex Paste Adhesive 902 Fluxit Spreader 903 Carbide a n d Carbon Chemicals Carp., Fine Chemicals Div., New York 17, N. Y . Tergitol 4 1001 Tergitol 7 1002 Polyethylene Glycol 200 1003 Polyethylene Glycol 600 1004 Soecial Emulsifier 75H14S 1005 1006
;i%
___
%g
.
1101 1201 1202 1203 1301 1401 1501 1502 1601 1602 1701 1801 1901 2001 2002 2101 2102
Acto 500 Floridin Co., Inc., Warren, Pa. Florigel GeneT&%emical Co., Allied Chemical & Dye Carp., New York 6, N. Y. Filmf as t Glyco Products Co., In:., Brooklyn 2, N. Y Aquaresin, glycol bori-borate James Good Co., Philadelphia 25, Pa. Goodrite pol ethylene polysulfide (Peps) Geon Latex $1-X
Ohio
In Figure 2, a rark of slides is shown through the open door of the dusting chamber in position to receive a deposit. Thc course of the air-return pipe inside the chamber may also be seen. The compressed air service line is shown a t the right. This use of glass slides instead of living leaves is subject to objections. The chemical and physical dissimilarities of the irregular, cutinized surface of the living leaf to that of highly polished and wettable, chemically inert glass are numerous enough in so far as they are known and probably equally important in aspects as yet unrecognized. I n the study of adhesives especially, the characteristic affinities of thc surfaces of the test objects are of major importance and the possibility must be faced that conclusions drawn from such a study as this with glass may be found to be invalid for predicting the results of similar work with leaves. Furthermore, while the irregularities of the surface of a leaf may retain residue particles that must
Code No. Geon Latex 19-X 2103 Griffin Chemical Co., S a n Francisco, Calif 2201 S-14 R-29 2202 P-122 2203 M-14 2204 Hercules Powder Co., Naval Stores Dept., Wilmington 99, Del Vinsol Emulsion 2301 Kay-Fries Chemicals, Inc.. New P o r k 17, N. Y. Penetrol 2401 Kessler Chemical Co., Inc , Philadelphia 35, Pa. Polyethylene glycol 600 monooleate 2501 Polyethylene glycol 400 dioleate 2502 Diethylene glycol dioleate 2503 Butyl stearate 2504 Diethylene glycol monooleate 2505 Diglycol oleate 2506 Ethylene glycol monooleate 2507 Methyl oleate 2508 Propylene glycol monooleate 2509 Methyl Cellosolve oleate 2510 Ethyl oleate 2511 Biitvl oleate 2512 ProGyGne- glycol dioleate 2513 Butyl Cellosolve oleate 2514 Glyceryl monooleate 2515 Miller Products Co., Portland 1, Ore. Miller’s 101 Spreader-Sticker 2601 Monsanto Chemical Co., Central Research Deut.. D a v t o n 7, Ohio, Sterox D 2701 Sticking agent 198687 2702 Sticking agent 194136-B 2703 Sticking agent 194136-A 2704 National Adhesives Div., N a t i o i i ~ lStarch Products Inc., h-ew York 16, N. Y. Dex No. 5574 2801 Dex No. 531 2802 2803 F o t ~ ~ t i t e achinery Corp., Niagara Chemical Div., Middleport, K.Y 2901 Niagara Dustik Onyx Oil & Chemical Co., .Jersey City 2, N. .J. Resin S-69 3001 Resin AA-40 3002 Resin 362 3003 Orbis Products Corp.. New York, N.Y. 3101 Orbin Stick-on 3102 Orbin G l u t u Oronite Chemical Co., Kew York 20, N. Y. 3201 Polybutene No. 8 B . G. P r a t t Co., Hackensack, N. J. 3301 Pratt’s Spray Catalyzer Rohm & Haas Co., Philadelphia 3 , 131. Triton B-1956 3401 Triton X-120 3402 Tamol N 3403 Shell Oil Co., Inc., Special Products Dept.. New York 20, N. T. 3501 Shell base oil 10 ACX 54 3502 A C X 151 3503 Silmo Chemical Carp., Vineland, N.J. Spread-01 3601 Stanco Distributors, Inc , Chemical Pi,oducts Dept., New York 11, N.. Y. . _. 3701 Acto500 3702 Acto 600 The United States Stoneware Co., Akron 9, Ohio 3801 Tygobond 30 adhesive R. T. Vanderbilt Co., Inc.. New York 17. N. Y. 3901 Veegum Darvan No. 1 3902 :d-0-Stik , Inc., Springfield, N. J. 4001 micals Corp., Wyandotte, Mich. hrbose 4101 hefnical Co., Cleveland. Ohio 4201
.
slip from glass, the leaf can and will bend and cause a deposit to Iosc a hold that it would be well able to keep on a glass surface. On the other hand, the chemical stability of glass permits a single slide to be subjected to a swies of rains, and the amount of the residue to be determined after each rain by simple weighing. Differences such as those between young and old leaves are not present and the dimensions are readily measurable for glass. Because of their fixed shape and rigidity the slides can be placed in chosen positions with assurance so that this experimental condition can be reproduced with much greater precision than R ith leaves. In preliminary trials it was found expedient to place two slides in the clips together and after the dusting to discard the one that did not face the mist duster. This step was called “backing the slides” and gave a deposit all on one side of the test slides so that only the direct effect of the rain was measured. The position
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INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 42, No. 2
adopted for the rack in the rouT ~ B L E11. RESULTS OF TESTS OF MATERIALS IN SIIALL EXPERIMEYTAI, MIST DUSTER tine triab was such that the (1948) slides occupied an area 8.5 Initial inches (21 cm.)horizontally X 3 Denopit. inches (7.5 em.) vertically, per2: Peicentage Retalned after Designated S u m b e r of Rains Code Remarks pendicular to the axis of the ap\ I m Slidea 1 2 3 4 5 6 7 8 A- 0 paratus and 39 inches (1 meter) Note light deposit 0.0053 15 0 13 0 101 102 0 , 0 0 5 5 3 5 . 0 32 0 29:o 2 s : o 2 i : o 2 i : o 2 7 : o 2 7 : o Note light deposit from the mist duster. The Note light deposit .. I03 0.0082 3 0 . 0 2 i . 0 25.0 23 0 2 2 . 0 2 2 . 0 2 1 . 0 Impossible b y standard treatment , . .. ,. .. .. .. .. 201 .... center of the area was 17.5 0'40 . . , . , , .. ., .. . . Special handling 202 0.1591 inches (44em.) above the floor 0.8 . .. . , . .. . 301 0.0413 2 5 302 0 0323 or 6.5 inches (16.5 em.) below 1 8 ' 0 1 i : o 17:O 2 0 . 0 23:O 40 1 0 0297 1 3 . 0 1 2 . 0 12 0 22.0 17.0 402 0,0254 the axis of the discharge port of 8.0 1 2 . 0 12 0 i i . 0 i o . 0 1 0 . 0 1 0 . 0 1 0 . 0 403 0.0236 the blower and 7 inches (18 em.) 2 3 . 0 2 2 . 0 21.0 2 1 . 0 2 0 . 0 1 9 . 0 1 8 . 0 1 8 . 0 404 0.0183 1 4 . 0 1 3 . 0 1 2 . 0 12.0 1 1 . 0 1 4 . 0 1 6 . 0 1 4 . 0 405 0.0150 to the left of the axis. Si.: l A . O 1 6 . 0 16 0 1 4 . 0 1 3 . 0 1 2 . 0 1 2 . 0 1 2 . 0 406 0.0231 9.0 1 1 . 0 10 0 10.0 1 0 . 0 407 0,0160 replicate slides were used for 3 8 . 0 3 4 . 0 3 1 . 0 3 0 . 0 2 9 . 0 27:O 2 i : O 2 i : o 408 0.0206 each test. 1 9 . 0 1 7 . 0 17.0 1 6 . 0 l G . O 1 6 . 0 1 0 . 0 1 5 . 0 409 0.1034 1 4 . 0 12 0 12.0 1 2 . 0 1 1 . 0 1 1 . 0 9 . 0 410 0,0206 When the slides were dry i:o 1 0 1.0 2.0 2.0 1 0 7.0 3 0 411 0.1639 Difficult to disperse 0 7 412 0.1094 they were stored overnight in a 1 9 I O 0 8 0 6 413 0.1548 desiccator over calcined cal0.7 .. .. 0.1418 414 Rubbery m a t e i d settled ocit 1.2 0 : s 0'6 1.9 4.1 415 0.1278 cium sulfate, brought to equi1.4 1 . 0 0.7 416 0.1379 2 ' 6 2 1 4 . 3 i : e 6 . 0 4 . d 301 0.0430 librium with the environment 6.4 3.1 2.5 1 8 60 1 0.0416 of the balance, and weighed. Note light deposit 12.0 12.0 7.6 70 1 0,0040 2 1 80 I 0.0291 Akfter they had been weighed Stabilized a t thle point l i ' 0 22 0 l i 0 14 0 1 1 0 901 0.0260 3 6 902 0.0264 they were clipped in racks like 3 9 903 0.0202 those used for dusting and subOutside of principal dust Gone 1001 0 . 0 0 2 1 24 0 Normal operation 5 8 0.0517 jected to an artificial rain. This 1002 0 9 0.0065 1003 9 6 rain was the spray from a verv 0,0091 9 1 14 0 12 0 1 1 0 11 0 1004 0 , 009a old "Bordeaux nozzle" in which 1006 0 . 0 1 $30 2 7 0 13 1006 0 2388 a cylindrical jet is spread out 2 9 0 031.5 1101 I 1 1102 into a fan bj- impinging against 0.0574 1201 0.0144 4 8 a plane surface inclined to it at I202 1 0 0.0306 1 0 1203 0.0.538 a n acute angle. To assure a $ 3 1301 0.0273 0 8 4'6 1401 constant delivery of water the 0 0207 P u t aside fop.lurther atudr 5 2 . 0 4 9 . 0 43:O 4 0 : O 40:O 34 0 33 0 1301 0.0319 valve on the water line was 9 3 i.7 . . 1502 0.0168 0 . 4 . . . . . 1601 0.1239 opened full and the water 1 2 n. 0327 1802 2 1 1701 0,0354 passed out of it through a glass 3 8 0.0239 1801 orifice firmly jammed into the 0 4 1901 0.0640 1 3 2001 0.0171 outlet pipe, -4rain gage was 0,01!10 2002 19:4 19 4 1 9 ' 1 constructed to measure this rain 2101 0.0282 2102 0,0323 and ascertain its uniformity in , . 2103 0.0210 the exact plane where the slides were to receive it. It fell off 20% toward the skirts of the (34 * 4 mm.) in 1 mlnute; the variations being a t the same jet, but held to 1.47 * 0.15 inches per minute (37 * 4 mm.) time for reproducibility and position along the row. While this in the middle. The most probable figure is 1.35 * 0.15 inches is an excessive rainfall as a natural occurrence in 1 minute, still none of the drops appeared to exceed 1 mm. in diameter so that. although they followed each other a t extremely short intervals, there mas no battering effect. Figure 4 shows the apparatus for the artificial rains in operation. K i t h the equipment at hand it was not possible to provide a lain of less intensity over the area occupied by a set of 6 slides except a t a great sacrifice in uniformity. The rain nozzle n.as mounted in a support that kept it in a fixed position relative to the position occupied by the rack of slides. This was over a sink so that the water was not troublesome. When a single set of 6 slides was subjected to a series of rains, they were shifted about in the rack for each rain to equalize the exposures. After the rain the slides were dried and conditioned as before and weighed again. This process was repeated until the residue weighed less than 1 mg.
2";;
"
MATERIALS TESTED
I'igure 4.
Set of Six Slides Receiving an Artificial Rain
Although it must be dispersed in water to be applied, a good adhesive for these purposes must resist dispersin after it has been dried on the slides. This would be met by an emufsion that resisted i edispersion or by a slow-setting plastic originally dispersible in water. It is intended that these properties, as embodied in known materials, should be examined. At the time this work was started there mere already many commercial products of undisclosed com-
INDUSTRIAL AND ENGINEERING CHEMISTRY
February 1950
TABLE 11. (Continued)
1
Code No. 2201 2202 2203 2204 2301 2401 2501 2502 2503 2504 2505 2506 2507 2.508 2509 2510 2511 2512 2513 2514 2515 2601 2701 2702 2703 2704 2801 2802 2803 2901 3001 3002 3003 3101 3102 3201 3301 3401 3402 3403 3501 3502 3503 3601 3701 3702 3801 3901 3902 4001 .4101 4201 Water a
Initial Deuositp Remarks 26’?)5 Percentage Retained after Designated Number of Rains Mm. Slide* 1 2 3 4 6 6 7 8 . . . . . . . . . . .. 0.0549 0.9 . . . . . . . . . . .. 0.0617 1.1 . . . . . . . . . . .. 0.01378 1.4 .. 0.0416 1.1 i :2 4:0 2 . 8 2 . 7 2 : 4 2 : 3 0.0721 9.8 .. 2 0 1.1 1.0 0.0897 7.0 . . 1 1 : l 6 . 8 6 . 0 5 : 3 5 : 3 Stabilized a t this point 12.9 0.0480 .. Stabilized a t this point 1.9 1.6 1.6 1.6 2.4 0.0871 . . . . . . . . . . . . 0.31 0,2333 .. 0.46 0.1543 .. 0.34 0.1935 .. 0.94 0.0798 , . 1.77 0.0807 .. 0.37 0.1741 1 . 0 1 . . . . . . . . . . 2.11 0.0853 .. 0.68 . . . . . . . . . . 0.1280 . . . . . . . . . . 0.08 0.2136 0.27 0.1363 Stabilized a t this point 1 1 . 3 8 6 : 5 4 6:13 5 : 6 7 5 : 5 4 5 : 3 6 . . 0.0744 1 . 2 5 0.41 0,1583 14: 1 1 7 . 1 l k : 2 15:6 1 4 : 9 1 4 : 3 0.0938 20.7 . . . . 2.2 .. 5.0 0,0378 7.4 6:6 4:8 . . . . .. 10.0 0.0207 . . . . . . . . . . .. 3.9 0.0351 . . . . . . . . .. 1.2 0.0189 . . . . . . . . .. 10.0 g : 4 0.0111 . . . . . . . . . . .. 1.4 0.0344 .. 0.7 0.0417 f ; : 2 4 : 4 3 : s 3 : o 2 : 2 , . 7.7 0,0471 .. Note lieht deoosit .. 0,0020 3 4 . 5 2 6 . 0 4.6 4.2 4:2 4:1 .. , . Stabillzed a t ~ i h i spoinr 7.3 0.0429 .. Stabilized at this point 6.8 6.8 6.5 .. 8.3 0,0257 .. . . . . Stabilized a t t h i s point 14.3 13.8 13.8 13.6 0.0252 2.6 1.5 . . . . . . 4.4 0.0436 5 . 1 . . . . . . . . . . 11.3 0.0154 .. 0.53 . . . . . . . . . . 0.2215 0.0348 2.3 716 6:4 5:6 :.’ .. 9.6 0.0188 . . . . . . . . . . .. 1.6 0,0477 .. . . . . . . . .. 0.6 0.0675 . . . . . . . . . . .. 0.02 0.1865 0.35 . . . . . . . . . . 0.1573 . . . . . . . . .. 0.36 0.2822 . . . . . . . . . .. 2.5 0,0201 . . . . . . . . . . . 0.8 0.0363 .. . . . . . . .. 1.0 0.0246 .. . . . . . . . .. Impossible to test by standard treat.. ment 0.0166 3.2 .. , . ., .. , , .. , . 0.0286 3.2 0.0826 8 1 . 0 7210 6 0 : O 50:O 4.510 40:O 3k:O 35;O Set a s i d e f o r f u r t h e r s t u d y 0.0545 6 8 . 0 4 3 . 0 3 3 . 0 2 7 . 0 2 4 . 0 2 2 . 0 2 2 . 0 1 8 . 0 Set a s i d e f o r f u r t h e r study n.....0636 0.4 . . . . . . . . . . . . . . 0.0247 1.8 . . . . . . . . . . . . , 0.1378 0.47 . . . . . . . . . . . . . . All deposits 0.5 mg. after one rain
..
. I I .
..
::
.
Average of six
position offered for purposes like this, and so it was proposed to test the apparatus and technique by making a comprehensive survey of all materials of known or unknown composition offered for this purpose. There is considerable literature on adhesives or “stickers” in pesticidal practice, but it was believed irrelevant because of differences in the operation. Lists of surface-active agents that are important in work on wetting and detergency are irrelevant and are several years old (g,7). Advertising matter in entomological (especially Entoma), phytopathological, horticultural, and chemical literature was scanned and some eighty letters sent out. About half of those addressed responded by sending in a total of 110 samples; one fourth did not reply; and one fourth answered that they had nothing to offer for the test proposed. The list of those who sent samples is in Table I. The adhesives were all tested as dispersions in water a t the rate of 4 grams in 800 ml. Many of the materials did not dissolve a t this ratio, and a number of the prepared stickers dispersed as emulsions. If a dispersion could be effected a t all the sample was treated like all the rest, with the expectation that more extensive tests would be made later in such cases as seemed sufficiently promising to examine further. The ratio of adhesive to sulfur dust thus was always 1 to 50. If it seems that the tests are unreasonably severe, it is to be pointed out that a number of samples met the requirements. The series of oleates sent by the Kessler Chemical Company, Inc. (Philadelphia, Pa.), Nos. 2501 to 2514, offered an opportunity to relate the results of tests to compounds of known composition although only a limited range of t y es was represented. Only one of these samples could be dispersefin water as received, so it was necessary to emulsify the others. A 10% solution of the Armour soap emulsifier (No. 601) was prepared. This soap appeared to be similar to others used for such a purpose in previous experi-
329 ence ( 4 ) and could have been rep1ace.d by a t least four other samples of the present series. Twenty grams of the sample to be emulsified and 10 ml. of the solution of soap were passed three times through a laboratory hand homogenizer. The water used to rinse each time was taken from a 170-ml. portion, so that a t the end of the third passage the volume was within 1ml. of 200 ml. Of this, 40 ml. were diluted t o 800 and this was used as the liquid in theThree test. of the samples sub-
mitted, Nos. 201. 202. and 3801, proved refractory’ even to this treatment. No. 3801 appeared to be a bonding material similar to rubber cement, and it was not tested because of the very strong probability that any dispersion or emulsion of the material mjght break down during the test and clog the liquid-dispensing apparatus. Nos. 201 and 202 resembled the tacky material that is calendered onto the face of pressure-sensitive tapes. They were so similar that it was believed that a test of either would give a good indication of what might be expected of the other. Accordingly, equal parts of 202 and 3501 were stirred together. No. 3501 might be thought of as a heavy naphtha or very light lubricating oil. Perhaps a better solvent for No, 202 could be found if more effort were expended on the search; however, any emulsion, rather than the best, was the object sought. A portion of this mixture was then emulsified as described for the 2500 series a t the ratio for either of the constituents alone. Thus there was a double quantity of material in this single test. The emulsion as made was not as good as was desired, for it “broke” a little and deposited its sticky oil phase on the walls of the containers. Some of the materials promoted a heavy initial deposit, and for this reason the weights of the original deposits are shown in the table in terms of grams per slide, 25 X 75 mm. in area. Each of these and of the percentages shown is the average of six, Another reason for the inclusion of this column was that it serves to show why the test of an originally light deposit was terminated while a considerable percentage still adhered. If the deposit had originally been only a few milligrams the large percentage remaining would still be too small to weigh. A deposit was declared to have become “stabilized” and further testing was stopped when, following two rains, no change had occurred in the weights of three or more of the six slides, and no more than 0.4 mg. in any of the rest. Preliminary work had shown that no further significant change was to be expected. Very few materials gave deposits that were weighable after eight rains, and testing was arbitrarily stopped a t that point, leaving comparison between these few to be made by means of the percentage values. DISCUSSION OF RESULTS
The pertinence of the data for field conditions is subject t o limitations imposed by the conditions-for example, the nature of the test objects and of the artificial rain-and by the fact that the nature of the deposits was completely ignored. The objections that might be raised against the use of glass slides have been mentioned above and the nature of the artificial rain has been discussed. Some remarks on the nature of the deposits are
330
INDUSTRIAL AND ENGINEERING CHEMISTRY
needed. Many of the deposits vere extremely irregular and would have been objectionable if they had been applied to leaves for protection from fungi. Others were satisfactory as first laid down but became much more defective after exposure t o rain than the loss in their weight indicated. It was intended to record the characteristics of the deposits by suitable photographs, but time and facilities did not permit it. This important step together with a comparison with the deposits on leaves for a selected few of the materials should be taken. I n spite of the fact that little information was supplied about the composition of the samples, some conchaions can be drawn fiom the results of the tests even if nothing more than the weights of the deposits are considered. Thirty-one of the 110 samples rctained weighable residues through four artificial rains of 1.33 inches; 23 withstood eight of these rains or else became stabilized and apparently would have maintained themselves through an indefinite number of rains. From the little that is known about their chemical make-up the following conclusions can be drawn: Those materials that are chiefly notable for their detergency, or effect upon the wetting and spreading properties of water, are unsuited for the purposes of the present work. Examples are the Tergitols, Penetrol, and petroleum oil sulfonates (Acto materials). None of the bentonites and none of the starch products offered promise. There is a suggestive similarity between the performance and appearance of materials under code numbers 4001 and 1501. Both appear t o have several com-
Coal Hy
Vol. 42, No. 2
ponents, one of which probably confers the observed effectiveness and the rest are required to permit that one to be properly dispersed. That such auxiliaries are not always necessary is demonstrated by 2501, polyethylene glycol monooleate, which was dispersible-actually soluble-in Tvater jus? as received, and which gave a good performance. The parallel performance manifested by 2513, propylene glycol dioleate, and 2515, glycerol monooleate, prevents an interpretation of the effect of a angle as opposed to two esterifying fatty acid residues. The unmodified soaps were unsuccessful. SUMMARY
An apparatus for the testing of adhesives for horticultural mist dusting and the method of operation is described. One hundred and ten samples, mostly commercial offerings, werc tested by it, and the results are presented. LITER4TURE CITED
Annual Report, Cornel1 University, 1945. Cupples, H. L., U . S. Dept. A g r . , Agr. Research Admin., Bur. Entornol. Plant Quarantine, E Series, Ciw. 426, 504, and 607. Glaves, J . Agr. Eng., 28, 551-2 (1947). Green, E. I,., IKD.Esc. CHEM.,19, 931 (1927). Green, E. L., unpublished data. Green, E. L., and Goldsvorthy, M. C., Phytopathology, 27, 957-70 (1937). Vanhntwerpen, F. J., IXD.ENG.CHEM.,35, 126 (1943).
RECEIVED January 12, 1949.
enation Ca
BATCH AUTOCLAVE TESTS SOL W’ELLER, R I . G. PELIPETZ, SAM FRIEDBIAN, AND H. H. STORCH B u r e a u of Mines, P i t t s b u r g h , P a . Comparative catalyst tests have been made for the hydrogenation of whole Bruceton coal (Pittsburgh bed), hand-picked Bruceton anthraxylon, and Rock Springs coal (Wyoming subbituminous). In all cases, ammonium chloride added by itself either had no action or decreased the liquefaction of coal. Tin added by itself showed moderate catalytic activity. The combination of tin plus halogen acid, however, shows a remarkable synergism and, with the possible exception of germanium plus halogen acid, constitutes perhaps the best known catalyst for coal hydrogenation. Ammonium chloride, hydrochloric acid, carbon tetrachloride, and the chloroacetic acids were all found to be essentially equivalent as promoters for tin. Sodium chloride is inert, while elemental chlorine exerts a harmful effect. RIolybdena, nickel on kieselguhr, and copper chromite were found to be relatively ineffective in all of these tests. Iron compounds were also found to be useless at initial hydrogen pressures of 1000 pounds per square inch. Zinc shows appreciable catalytic activity in the presence of ammonium chloride. I t was found possible to replace a t least 90% of the tin in a tin-ammonium chloride catalyst by zinc without appreciable loss of catalytic effectiveness. The physical distribution of tin was found to be important. However, if the physical distribution is good, tin may apparently be used i n almost any chemical form; tin, stannous sulfide, metastannic acid, and tin tetraphenyl were found to be equally effective in combination with ammonium chloride. Increase of metal (tin or zinc) concentration above 0.5% has little ef-
fect on the coal hydrogenation. The principal effect of an increase in ammonium chloride content (in the presence of tin or zinc) is to decrease the production of asphalt. High pressure tests (3700 pounds per square inch initial hydrogen pressure) on Rock Springs coal indicate that iron catalysts, such as ferrous sulfate, pyrite, and “red mud,” can be used to good effect though they fall considerably short of tin plus ammonium chloride or zinc plus ammonium chloride in promoting coal liquefaction.
A
TTEMPTS to improve ?he economic status of coal hydro genation has led the Bureau of Mines t o a continuing search for cheaper and more effective catalysts for the process. These studies have two aspects: one, a semiempirical trial of all reasonable catalysts; the other, an attempt to understand the mechanism by which the best catalysts operate, so that improvement of catalysts can be put on a rational basis. Only a few comparative studies of coal hydrogenation catalysts have been published ( 1 , 4 , 7 , 8, 10). The work reported here constitutes an extension of published results to additional catalysts and coals. APPARATUS AA’D PROCEDURE
A detailed description of the hydrogenation equipment has been published ( 6 ) . A Pyrex No. 774 glass liner was used in all of the experiments; this is vital in catalyst studies, for otherwise the autoclave will show “memory” effects. No vehicle was used in any of the experiments. The 1.2-liter autoclave was charged with 50 grams of dry, powdered coal and v i t h catalyst,
