Document 06pJXwVk5nYYV5qQQmX2bzKYO

United States Patent Office 3,083,089 Patented Mar- 26, 1963 1 3.083.089 GRANULAR HERBICIDAL COMPOSITION AND METHOD Victor Renner. Marysville. Ohio, assignor to The O. M. Scott & Sons Company. Marysville. Ohio, a corporation of Ohio No Drawing. Piled July 6. 19S9. Ser. No. 824,953 dry herbicide composition especially suited for selective control of noxious weeds and the like: (1) In which the herbicidally active ingredient is bond ed to the surfaces of a dry carrier by adsorption, virtually eliminating release of toxic dusts during application: (2) In which substantially all of the herbicidally active Ingredient is firmly bonded to a dry. granular carrier by 19 Claims- (Cl. 71--2.4) adsorption so that said active ingredient is not quickly. .. . _ removed by wind action, or rain or soil water leach, and . This invention relates to herbicides, and more par- 10 therefore is in contact with the treated plants for longer, titcVuiilarlyv itno whehrbii-cMida,il fonrrmmurlaiftlitoi.n--s- fonr. tht.e_ --con.t--roil o~fr m0re effective periods of time: undesirable grasses and weeds found among turf grasses. (3) In which the herbicidally active ingredient is sub This application is a continuation-in-part of applicant's copending applications Serial Nos. 634.922. filed Jan- stantially resistant to soil water leach so that no substan tial injury results to roots of woody plants adjacent the uary 18. 1957. and 660.452. filed May 21. 1957. both now IS treated area, nor to woody roots close to the soil in the aaLbai nrdfloane-- d. AA npnpIliiacaaItiiaon CSl eUr_ifa1l INsfao. 63j4t .92^2 Ii_s --a c^on t. reat_ed, area: ticuatioc of applicant's application Serial No. 172.679. (4) Which is free-flowing so that it can be easily ap filed July E. 1950. and applicant's application Serial No. plied in controlled quantities by such means as conven 585.270. filed May 16. 1956. the latter of which was a tional lawn spreaders', and continuation-in-part of said application Serial No. 172.679. 20 (5) Which comprises a dry. granular carrier of finely and both of which are now abandoned. Application divided expanded vermiculite having an herbicidal com Serial No. 660.452 is also a continuation-in-part of said application Serial No. 172,679. pound and a low-volatile organic solvent firmly adsorhed on the surfaces thereof. Various dry formulations of herbicide compositions for It is another principal object of the present invention controlling noxious plants have been tried heretofore. 25 (q provide a new and improved method of making the However, such prior dry formulations have some serious novel granular vermiculite carrier herbicides of appli shortcomings and present numerous problems. In par cant's invention to impart to them the characteristics that ticular. the dry herbicidal formulations heretofore used achieve the aforementioned objects and advantages. have presented a serious dst problem because substantial More especially, it is an object of the present invention quantifies of fines or dust are raised from the herbicide 30 to provide novel methods of making herbicides and to formulation when it is applied. (Dust has been defined achieve improved herbicides thereby in which: as all solid particles capable of being suspended in the (6) A herbicidally active compound, either dissolved air. usually from 1-150 microns in diameter.) Such or emulsified in a suitable vehicle therefor, is added to prior herbicide compositions usually contain as an active finely divided expanded vermiculite in granular fonn. the Ingredient some chemical compound, like arsenic, phcnyl- 35 quantities of ingredients being such that substantially all mercuric or 2.4-dichlorophenoxy acetic add. which is of the herbicidally active compound is bonded by adsorp- toxic to humans and other mammals, so that dust arising lion to the platelets of the vermiculite: and - from the herbicide formulations during their application (7) Synergistic effects are obtained from the use of may have harmful effects. In fact, in some states it is N- 1-naphthyl phthalamic acid in combination with phenyl- iuinnllaatwiiffnull ttrot Iulesea or rsaeilll fdlprtyf ffrotrnmrtulllleatliirotnnsr rotff rcoearttoainn herbi .m.....e....r...c...u._ric _c__o__m___p__o__u__n__d_ss_ . cidal compositions which contain dust. Furthermore, the These and other objects of the invention will become fines or dust of prior dry herbicidal formulations float in more fully apparent from the following description, dis the air currents and drift onto adjoining vegetation such cussion and appended claims. _ as garden crops and flowers, so that such prior dry formu lations cannot he safely applied on home lawns or other 45 It has been discovered that when a solution1 of a herbicidally active ingredient and a suitable solvent there areas adjacent desirahle plants which may be adversely affected by the herbicide. for is properly coated on granular, finely divided expanded vermiculite so that substantially all of the herbicidal Another problem not only with prior dry herbicide compound becomes firmly adsorbed on the surfaces of the formulations but with herbicides in the form of solu- vermiculite. the result will be a formulation which is tio--ns /(:i.e-,. -s--pr--ays)' is *t*h--at the active ingredient of th*--e dust-free and from which the active ingredient will be herbicide is rapidly removed from the carrier by wind only slowly leached from the vermiculite. This phenom action, or leaching by rain or soil water, so that the active enon is in sharp contradistinction to prior art methods herbicide ingredient is cot ic contact with the treated in which a solid carrier material has been literally soaked plant as long as it should be to be fully effective. A re 55 with a herbicidal composition, resulting not only in small lated problem, particularly in prior formulations for quantities of adsorbed herbicidal compound but also in clovfr control, is that the active ingredient is often too large quantities of adsorbed herbicidal compound retained readily leached from the carrier to the root zone of de Within the voids of the expanded vermiculite particles sirable woody plants bordering the lawn area and injures and which is relatively quickly leached from said solid such plants, Also, herbicides as used in the above forms qq carrier, resulting in ineffective weed control and in a have been found to' seriously discolor the surrounding formulation which is difficult to handle. turf grass as . they fall alike on undesirable growths and In accordance with this invention, a preselected herbi turf grass. . cidally active ingredient is added to a solvent therefor, Still another disadvantage of some prior dry formula the herbicidal compound being present in an amount suf- tions is that they are cot free-flowing and thus cannot be ^ ficient to be toxic to selected plants and the solvent being easily applied in desired controlled quantities by me used at least in a quantity sufficient to dissolve (or to chanical means like conventional lawn spreaders. emulsify) the herbicide. The relative quactities of in- Accordingly, it is a principal object of the present in vention to provide a dry herbicide composition especially suited for selective control of noxious weeds and the like 70 * ".Solution" sind "disaolve." when UBed in the specification tmd claims, shall also be construed to Include emulsion" find "emulsify," respectively: the word "vehlclo" when used which is free-flowing and substantially dust-free. _ Other objects of the instant invention are to provide a In tho specification and claims shall be construed to denote 0 substance In which the herbicidal or phytocldnl compound limy be dissolved or emulsified. 3,083,089 3 gredients should be such that substantially all the herbi 4 (c) For 'broadleaf weed control, one may use cide will be adsorbed on the surfaces of the vermiculite. The resulting solution (or emulsion) is then sprayed sub 2.4- dichiorophenoxyacetic acid; stantially uniformly onto granular, finely divided expand 2.3.6- trichlorophenyIacetic acid; ed vermiculite in an amount at least sufficient to provide 5 IPC (isopropyl phenylcarbamate); the toxic concentration required for the service for which CIPC (chloroisopropyl phenylcarbamate); the composition is intended. After the vermiculite has 2.4.6- trichlorObenzoic acid; beeli sprayed, the resulting composition is thoroughly o-ch!orophenoxyacetic acid; mixed to obtain a homogeneous-appearing mass. 2.4.6- trichlorophenoxyacetic acid; The granular composition is readily spread on lawn 10 2,3,4,6Jtetrachltrrophenoxyacetic: acid; or turf infested with noxious weeds, using conventional 2-(2,4,5-trichlorophenoxy) propionic acid; lawn fertilizer or seed spreaders. After one to four p-bromophenoxyacetic acid; weeks, the destruction of the weeds and the growth of 2.4- dibromopbenoxyacetic acid; new turf grass is noticeably evident. 2.4.6- tribromophenoxyacetic acid; Numerous herbicides may be used in the instant herbi- 15 p-iodophenoxyacetic acid; cidaily active compositions, the choice depending largely p-fluorophenoxyacetic acid; iipon the purpose for which .the composition is being 2.4- di-fiuorophenoxyacetic acid; used. For example, where it is desired to eliminate 4-chIoro-o-toloxyacetic acid; crabgrass, the primary toxic ingredient of the composition 4-chloro-m-toloxyacetic acid; will be a phenylmercuric compound; when the growth 20 4-chloro-2-ethyiphenoxyacetic acid; to be eradicated is clover, haloaryloxy substituted ali 4-chloro-3,5-dimethyiphenoxyacetic acid; phatic acids and their esters are preferable; etc. Aside 2-chioro-l-caphthoxyacetic acid; from the requirement that the herbicide be toxic to the 2.4- dichIoro-l-naphthoxyacetic acid; and particular growth to be eradicated, the primary limita b-( 2-chtoro- 1-naphthoxy) -propionic acid. tion on the choice of herbicidally active ingredient is that said ingredient must be either substantially soluble or emulsifiable in the particular solvent used as a ve hicle and must be capable of being adsorbed on the sur faces of the expanded vermiculite. Unless the herbi cidally active ingredients possess the foregoing characteristic, they will not be adsorbed on the vermiculite but will, at -best, be "stuck" onto the vermiculite surfaces (as in copending application Serial. No. 659,486, filed May 16, 1957, now abandoned), and Will be leached from the vermiculite at a much faster rate than would be desirable for the uses here contemplated. In general, the preferred herbicidally active ingredients used in the in stant invention may be broken down into two groups:a (1) Group I includes the following compounds, broken 25 30 35 (tf) For grassy weed control, trichloroacetic acid; 2,2dichioropropionic acid; IPC; and CIPC may be used. (2) Group II includes the following compounds, broken down by use to which they will be put: (a) For crabgrass control, preferable compounds in clude chlordane3 (-60% octach!oro-4,7-methano tetrahydroindane [CioH6C!6] and 40% related compounds); and Neburon (Du Font's trademark for 1-n-butyl-3-[3,4-dichlorophenyl]-I-methylurea). (f>) For clover control, the following compounds are useful: 2,4,5-trichlorophenoxyacetic acid; 2,4,6-trichlorobenzoic add; and 2,3,6-trichlorophenyIacetic acid. (c) For general broadleaf weed control, preferred com pounds -include 2,4-dicb!oropbenoxyacetic acid; 2,3,6-trichlorophecylacetic acid; IPC; CIPC; and 2,4,6-trichloro- down by the use to which they will be put: 40 benzoic acid. (a) For crabgrass control, phenylmercuric compounds, ((f) For grassy weed control, pentachlorophenol and such as the hydroxide or salts of aliphatic acids, are hexachloroacetone may be used. preferable. Other toxic ingredients may also be present, In addition to the above-listed herbicides, group U such as the reaction product of the solvent with phenyl- herbicides also include esters of the haloaryloxy aliphatic mercuric compounds. In addition, acids such as pro acids set forth in group I, such as (he methyl, ethyl, pionic, naphthyl pbthalamic acid and other acids may isopropyl, butyl, pentyl, propylene, glycol, butyl ether, be added to form phenylmercuric compounds. Exam butoxy ethanol, isooclyl, tetrahydrofurfuryl, butoxy- ples of the compounds which have been found particularly ethoxypropyl, and other esters. Generally speaking, useful are phenylmercuric hydroxide, oleate, acetate, 50 these esters have the same uses as the respective acids propionate, butyrate, amylate, hexanoate, and stearate. from which they are derived. Haloaryloxy derivatives (i>) For clover control, preferred compounds include of higher aliphatic acids and the corresponding haloaryl 2.4.5- trichlorophenoxyacetic acid; oxy derivatives of such unsaturated aliphatic acids as acrylic acid and its homologues may also be used. TBA (2,4,6-trichlorobeczoic acid); gg Of the foregoing compounds, the phenylmercuries, Endothal (disodium-3,6-endoxohexahydrophthalic acid); haloaryloxy substituted aliphatic acids and esters and 2.3.6- trichlorophenyIacetic acid; chlordane have to date proved to be the most effective o-chlorophenoxyacetic acid; herbicides in actual test results for the types of control 2.4.6- trlcblorophenoxyacetic acid; above indicated. pectachlorophenoxyacctic acid; go Solvents usable in the instant invention may include 2-(2,4,5-trich!orophenoxy) propionic acid; any material which is readily adsorbed on the surfaces 2,4-dihromophenoxyacetic acid; of expanded vermiculite and in which the selected her- 2.4.6- tribromophenoxyacetic acid; p-iodophenoxyacetic acid; 4-ch!oro-o-to!oxyacetic acid; 4-chloro-m-toloxyacetic acid; 4-chloro-2-ethylphenoxyacetic acid; and 4-chloro-3,5-dimethyJphccbxyacetic acid. bicidaliy active material may be either dissolved or emul sified. . The solvent selected preferably should have low 65 volatility to prevent its ready evaporation under out door conditions of use and, since all solvents are at least somewhat toxic and, for the most part, have only a limited degree of selectivity, should not be used in a concentration or amount such as to impair the toxic selec 3The purpose of dividing the iierbicidally active Inured, tents Into two groups is to classify them depending upon the solvents with will eh they ore used, ns will be more fully dis cussed infra. It is 10 be understood, however, that the usable hertncldes are not to be limited to those recited, but may Inciode others whleb meet the general reouirenients men tioned above. Including dcrivath-ee. laoiucrs. and other comppuudfi wiilch arts similarly loxle to ihc rceitod compounds. tivity of the overall formulation. If a quick release of the herbicidally active ingredient is desired, the solvent should be hygroscopic to speed dissolution of the her bicide under moist conditions. , "Made by Vclslcol Corp., Chicago. 111., aad other com- 3,083,089 s6 Assuming that the above conditions are met, the par transport the herhicidally active ingredient to and to effect ticular solvent to he used will he selected on the hasis its adsorption on the vermiculite carrier, less solvent of (1) the desired rate of Icachahility or release of the will he required where the herhicidally active ingredient herhkidal compound to the plant and/or soil; and (2) is in liquid form in the first instance (i.e., such as is the the particular herhicidally active ingredient used. 5 case where chlordane is the active berhicidat ingredient). Insofar as the second factor is concerned, when any Secondly, since, as aforesaid, the toxicity of the solvent of the herhicidally active ingredients included in group I, must be maintained at a minimum lest the toxic selectivity supra, is used, preferred solvents will include polyhydric of the formulation he impaired, this imposes an addi alcohols, glycol ethers and ketones, the former being tional limitation upon the total permissible quantity of the most commercially effective of the three solvent 10 solvent. Still another factor is the soluhility charac classes listed. teristics of the herhicidally active ingredient in the par Suitahle polyhydric alcohols include glycol and glyc erine as well as the higher molecular weight polyethylene ticular solvent used. In general, and bearing in mind the above mentioned and polypropylene glycols soliihie in water, Examples factors, it may he said that the quantity of solvent used of polyethylene glycols are the "Carhowaxes" manufac 15 should he at least sufficient to dissolve the herhicidally tured hy the Carhide and Carhon Chemicals Co., 30 E. active ingredient at a temperature helow its decomposi 42nd Street, New York 17, N.Y. Those "Carhowaxes" may he used which have numhers of from 600 to 6,000 with average molecular weights of from 570 to 7,500 tion point hut not so great as to impair the toxic selectiv ity of the formulation. The quantity of herhicida! in gredient should he sufficient to he toxic to the plant and viscosities in centistokes at 210 F. of from 10.5 to 20 growths which it is desired to eradicate. The comhined 900. Examples of other polyhydric alcohols Which may and relative quantities of solvent and herbicida! ingredient he used with equally good results are ethylene, propylene, dipropylene, triethylene and hexylene glycols; 2,2-diethyl1,3 propanediol; 2-cthyl-2-hutyl-1,3-propanediol; 1,5 should he such that substantially all of the herhicida! ingredient will be bonded hy adsorption to the platelets of the vermiculite. pentanediol; 2-ethy!-I,3-bexanedioI; as well as polyethyl 25 Using the ahove parameters as guides and with the ene and polypropylene glycols. application of known techniques, those skilled in the art Preferred glycol ethers are ethylene glycol monoethyl will have no difficulty choosing correct proportions of ether; ethylene glycol monomethy! ether; ethylene glycol ingredients. monohutyl ether; I-butoxyethoxy-2-propanol; diethylene In the following table, by way of example, is listed glycol monoethyl ether; diethylene glycol monomethy! 30 typical formulations, based upon the herhicidally active ether; diethylene glycol monohutyl ether; methoxytrigly- ingredient used, showing preferred proportions of mate col; and ethoxytriglycol. rials. Since these proportions may vary depending upon Among the ketones which may he used are acetone, the variety of factors set forth ahove, however, they methyl eihyl ketone and diisohutylketone. should not he deemed restrictive, hut illustrative only. When the herhicidally active ingredient is chosen from 35 those included in group II, supra, the preferred solvent TABLE A is an aliphatic or aromatic hydrocarbon hoiling within a range of from 300 to 600" F. The preferred sol Parts by Weight vents for this group are low molecular weight petroleum naphthas within a boiling range of 310" to 595 F. with 40 a low aromatic content of 15% by weight or less. These Herbicide] Compound Hcrblcldal Solvent Vermlcu* Compound lita solvents are generally referred to as mineral spirits and pbonylmcrcurlc and compounds.. 3-10 include, for example, Stoddard Solvent, mineral seal oil, {preferred kerosene and heavy naphtha. In cases where the herbicida! compound is ' insoluhle 45 tba............................................. 8 2-20 or difficult to dissolve in the ultimately desired solvent, Ifalooryloxyaoctlo acid and cam* 5-30 it may he first dissolved in a proportionately small quan tity of an intermediate solvent such as a low molecular JPC............................................. weight aliphatic hydrocarbon and this solution mixed cipc........................................... with the ultimately desired solvent. If an emulsion is 50 2,4,6-trichlorobenMic acid and by wtj 2-20 2-20 5-30 formed, a suitahle emulsifying agent of the types such as alky! aryl sulfonates and their sodium salts, polyglyco! 2-2,dEchloroproptonlc acid...... -- 2-20 2-20 20-1IQ esters of long chain organic acids, polyoxyethylated oils, and polyhydric alcohol esters, may he added to stabilize 2-l0 5-30 the emulsion. 55 2,3j6-trichloropl3enylacettc acid__ 5-30 60-W (preferred 70-75) 60-00 60-00 60-00 60-00 60-00 60-60 60-00 60-00 5-30 60-00 60-00 60-00 60-00 400-500 (preferred 450-475) 400-500 400-500 400-600 400-500 400-500 400-500 400-500 400-500 203-300 400-600 400-500 400-500 400-500 With all the ahove herhicides and solvents, the carrier materia! for the herhicida! compound of the instant in It is also possihle to use a combination of active in vention is granular, finely divided expanded vermiculite. gredients. For example, in clover control for lawns, it No. 4 vermiculite sold hy the Zonolite Company of is desirahle to limit 2,4-dichlorophenoxy acetic acid to Chicago, 111., has heen found to give good results. This 60 not more than 25% hy weight of the total active ingredi No. 4 expanded vermiculite has an average particle size ents used when it is comhined with 2,4,5-trichlorophen- of 420 microns, 95% of which are larger than 210 mi oxyacetic acid, which is used in the formulation in or crons in diameter. Other sizes of vermiculite which der to make the composition more effective for hroadleaf vary in mesh sizes of from 16 to 100 may he used with weed control in general. good results, although vermiculite having a mesh size 65 To impart desirable color to the product and the turf, of --20+75 (U.S. Standard Sieve) is preferred. The water-soluhle dyes such as malachite green, auramine, sizes of vermiculite are based on fractions passing through a given U.S. Standard Sieve and retained on a second sieve of smaller mesh size. The particular ratios of ingredients used in the formu lations of the instant invention are dependent upon a variety of factors and will necessarily vary depending oil soluble orange and crystal violet may be used with out impairing the effectiveness and with some possihle im provement in phytocida! and fungicidal results. The 70 amount of dye used is generally 2 to 6 parts by weight.4 It has also heen discovered that, especially in pre emergence weed control work, the addition of about 1 Upon the formulation employed. For example, since a prime purpose of the solvent is to serve as a vehicle to 75 `This range Is based upon the proportions of ingredients heretofore set forth. 3,083,089 .7 8 to 5 parts by weight* of "AJanap-1" N-J-naphthyJpbtbal- The vermiculite may also be heated to a temperature amic acid produced by the Naugatuck Chemical Com not to exceed the maximum temperature to which the pany) to herbicidal compositions containing a phenyl- solvent will be heated before being sprayed with the mercuric compound as the herbicidally active ingredient herbicidal-solvent solution, but this step is not necessary. increased the effectiveness of pre-emergencc crabgrnss 5 The herbicidal compound solubilized in the solvent en control, but did not alter the selective characteristics ables the herbicide to adsorptively bond with the vermic when used either as a pre-emergence or post-emergence ulite. The extent of bonding of ions to the vermiculite crabgrass control treatment. depends upon factors such as the concentration of the Furthermore, as will hereinafter be shown, the results solution, exposed surface areas, temperature, etc. obtained by such addition are unexpectedly synergistic, 10 The resulting solution is then sprayed onto finely di even when the addition is made to a phenylmercuric vided expanded vermiculite in an amount sufficient to compound which is ultimately absorbed in a carrier ma provide at least the toxic concentration of herbicidal terial other than expanded vermiculite (though, of course, compound necessary for control of the noxious weed. the phenylmercuric adsorbed on vermiculite is preferred, The coated vermiculite is then thoroughly mixed lo ob for the reasons heretofore set forth). 15 tain a homogeneous-appearing mass, after which the mix [For a detailed description of N-1-naphthyl phthal- ture is cooled and subsequently packaged. amic acid, reference should be made to United States The following examples will serve to illustrate the Patent 2,556,665, issued June 12, 1951.) invention: Further, it has been found that the addition of from Example / about 0.75 to 30 parts by weight of a wetting agent ex 20 6.0 lbs. technical grade phenylmercuric acetate (10% tended the effectiveness of the phenylmercuric formula tions so that approximately one-half of the previously moisture) was added with stirring to 73 lbs. of polyethyl ene glycol-600 which was at a temperature of 80" C. used amount of phenylmercuric produced satisfactory Complete dissolution was effected in two minutes. The control ('less than 0.75 part by weight would be relatively ineffective and more than 30 parts by weight would re 25 solution was allowed to cool to 50 C. and sprayed onto 450 lbs. of 60-mesh expanded vermiculite and then mixed sult in turf injury). This is not only true in pre-cmergence weed control treatment, but also in post-emergence for about 5 minutes in a ribbon blender. The above formulation proved to be extremely effec crabgrass control. tive as a post-emergence crabgrass control, as indicated A preferred wetting agent is "Ultrawet-K-Dcnse" (pro duced by the Atlantic Refining Company), an alkyl ben 30 by the following: the material was slightly aerated and applied in the evening to a lawn by spreading in an zene sodium sulfonate with the alkyl group having about amount of about 4.5 lbs. per 1000 square feet on three I to 15 carbon atoms. While this wetting agent is an separate occasions, at five-day intervals. At the end of anionic surface active agent, nonionic and cationic sur three weeks 85% of the crabgrass had died and new, face active agents may also he used, though the former have given better results. A suitable concentration of 35 wetting agent [percent active) is 85%. green spikes of young turf grass had appeared. Example II Surface active agents arc of course well known in the Vermiculite (No. 4)ft3_________________________ 41.0 art. For a description and a comprehensive list of sur Hexylene glycol__________lbs.. 17.0 face active agents available, reference should be had to "Synthetic Detergents: The Boom Won't Wash Out," re 40 Propylene glycol butyl ether ester of 2,4,5-trichlorophenoxy acetic acid (42.5% acid equivalent) lbs__30.0 printed from Chemical Week, copyright, 1955, by Mc Du Pont oil orangelbs__1.5 Graw-Hill Publishing Company, Inc., 330 West 42nd Street, Now York 36, New York. Another reference is Using the above formulation, the hexylene glycol was placed in a mixing tank and heated to a temperature of "Surface Active Agents, Their Chemistry and Tech nology," by Schwartz and Perry, published by Intersci 45 ence Publishers Inc., 1949. While it is not essential, it is highly desirable that all materials used in the formulation be pure in order to about 40" C. and the herbicidal ester and orange dye were added thereto. These ingredients were mixed for about lVt to 2 minutes until a good solution, was ob tained. This solution was sprayed over a 2 minute inter val onto the vermiculite which was in a ribbon blender, prevent side reactions, to maintain effective control and to obtain reproducible results. 50 In practicing the invention, the herbicidally active the blender being in operation during the spraying opera tion. Mixing was continued for about one minute. The finished free-flowing substantially dust-free herbicidal compound is first added to the solvent, which may be composition had a volume of approximately 45 cubic heated to speed dissolution of the herbicidal compound feet and was 1.7% active. A convenient method for and, incidentally, to reduce the viscosity of the solvent. Specific temperatures to which the solvent should be 55 varying the concentration of active ingredients in the final product is to vary the amount of vermiculite which heated to accomplish the above results will necessarily is treated with the herbicidal solution. vary depending upon the herbicidal. compound and sol vent used and may readily be determined by conven Example III tional laboratory techniques. For example, when phen- Lbs. ylmercurics and a polyhydric alcohol are used, the mini 00 Vermiculite (No. 4)1080 mum temperature of effective dissolution is 40" C., with Chlordane 290 a preferred range of 40"-60" C. Where a haloaryloxy substituted aliphatic acid is used, the temperature of the Stoddard solvent 75 Red dye 2 solvent should be 60 to 140" C. in the case of the higher molecular weight polyhydric alcohols; heating of the 05 . Using the above formulation, the dye is first dissolved lower molecular weight alcohols such as triethylene gly in the Stoddard Solvent and the chlordane added while col is not necessary. stirring for a sufficient time to thoroughly mix the in The solvent should not, in any event, be healed to gredients. After mixing, the solulion is heated and held temperatures at which decomposition of the herbicidal within the range of 90 to 100 F. to decrease viscosity compound (and dye when it is used) is apt to take place. 70 and improve adherence to the granular vermiculite. The Again, this maximum temperature is dependent upon heated solution is then sprayed onto the vermiculite while materials used, it being approximately 140" C. in the being agitated in a ribbon blender. case of a phenylmercuric-polyhydric alcohol mixture. The above formulation proved to be extremely effec tive as a pre-emergence crabgrass control and did not 0 See footnote 4. 70 injure or adversely affect turf grasses such as colonial 3,083,089 10 bentgrass (Agroslis tenuis), Kentucky bluegrass (Joa take place in such use. For this reason, it serves no use pratenses), creeping red fescue (Fesruca rubra) and Ber ful purpose to add the N-l-naphthyl phthalamic acid to muda (Cynodon clacrylon) when applied at more than tbe formulation which, except for the deletion of tbe double the rate required for pre-emergence crabgrass "AIanap-1," may be as set forth in Example IV above. control. 5 The `reason the herbicidal and solvent materials of the Example IV instant invention are adsorbed on the surfaces of vermic No. 4 vermiculitecu.ft_53-51 Hexylene glycol 60-65 C____________ __ lbs__34.0 Phenylmercurlc acetate (or 3 lbs. 1.5 oz. phenyl- mercuric propionate)lbs__3.0 10 * Propionic acid 98%ml_________________________ 125.0 28% ammonium hydroxideml 400.0 Dye: 80% malachite, 20% Auraminc 0____ oz__ 26.0 "Alanap-1"oz-- 30.0 "Ultrawet-K-Dcnse"lbs 3.0 ** 15 * ulite particles may be explained by the chemical and physical structure of the vermiculite itself. Vermiculite ore is a micaceous mineral that exfoliates when heated or subjected to certain chemical reactions. It is a hydrated magnesium-aluminum-iron silicate of monoclinic crystal structure with pseudo-hexagonal characteristics and pos sesses a Moh's scale hardness of 1.5. The chemical com position of ore and expanded vermiculite are identical ex cept for HjO content. The purpose of expanding vermic ulite is to enlarge or increase its porosity or the cellular The chemical ingredients were added to the hexylene condition of1 its laminae. glycol at 60 -65* C. in the order given. The phenyl- The platelet-type of laminar structure of vermiculite mercuric compound was thoroughly dispersed in the hexyl is directly responsible for the unique surface area and ene glycol during approximately a 1 minute period, go void,volume characteristics which appear to be in turn The propionic acid was then added. After approximately responsible for the physical and chemical properties of thirty seconds the ammonium hydroxide was added in the material that cause the solvents to be adsorbed thereon order to complete solubilization. Approximately thirty and thereby yield new and unexpectedly improved re seconds after the addition of the dye, the "Alanap-1" sults in dust-free toxic herbicides. The individual ele and "Ultrawet-K--Dense" (which formed a suspension) 25 mentary vermiculite platelets are approximately 9.3 A. were added in combination. thick (27,000,000 platelets would produce a stack one The resulting solution and suspension was sprayed on inch high). It has been found that the individual plate the vermiculite over 1VS-2 minute intervals while blend lets arc composed of two silica tetrahedral sheets bonded ing the mixture so as to provide a uniform coating- The to a central sheet of di-valent ions (primarily Mg++) in resulting composition was then mixed for an additional 30 octahedral configuration, and carry net negative charges 1-2 minutes. The final batch volume was approximately due to partial substitution of trivalcnt aluminum ions for 45 cu. ft. tetravalent silicon ions in the tetrahedral sheets (Grimm, The resulting composition was extremely effective as B. E., Clay Mineralogy, pp. 76-77, McGraw-Hill, 1953). a pre-emergencc crabgrass control. These negative charges, carried by the individual plate As heretofore indicated, the addition of relatively low 35 lets, are balanced by the presence of positively charged concentrations of N-l-naphthyl pbtbalamic acid (Alanap- cations such as Mg++, Ca++ and K+ which occupy posi 1) to phenylmercuric compounds adsorbed on expanded tions between the platelets. These interplatelet ions are vermiculite results in significant synergistic increases in relatively loosely held and may be removed and replaced the effectiveness in pre-cmcrgence crabgrass control of the stoichiomctrically by other ions without altering the com combination in comparison to that achieved by the use 40 position of structure Of the platelets. The ion (base) ex of phenylmercuric compounds alone. Such synergism is change capacity exhibited by vermiculite arises from this demonstrated by the results set forth in Table B, in which source, and makes possible adsorption bonding with both one treatment was applied to crabgrass (Digitaria san- organic and inorganic cations. The cation exchange ca gulnalis), seeded in pots of soil, 3 days after seeding pacity, determined by treating the vermiculite with neu at tbe rate of 5 pounds per 1000 sq. ft. In this test 45 tral ammonium acetate and then analyzing tbe thoroughly the composition of the phenylmercuric compounds was washed samples for nitrogen, was found to be in the order identical except for the addition of "Alanap-1" to the of 19.4 to 22.5 milli-equivalents for 100 grams. second compound. Studies have shown that the herbicides adsorbed on the TABLE B surfaces of the vermiculite are very resistant to leaching -------. 50 by water. The resistance of the herbicidal compound to Percent Percent Control Qrrcn Weight leaching by water varies with the compound. However, all of the adsorbed herbicidal compounds are retained much longer on the vermiculite than when adsorbed in 0.37% Micajj'lmorcuilc Acctfltc.............. ................. 0.22% "ALANAP-1'"................................................. 0.37% Pticnyimcrcurlc Acetatc+0.22% "AI.A- NAP-11'.............................................. ..................... the conventional carriers. 0lG3 ,e 16.00 65 Materials such as talc, fuller's earth, kieselguhr, diato- rnaceous earth, volcanic sand, pumice, chalk, woodflower, GO 2.85 nutshell flower, charcoal, inorganic phosphates, magne sium carbonates, bentonite and pyrophyllites have all been Percent Control--Percent or germinating pinnts controlled on basis or germination in check pots. used heretofore as carriers for herbicides in dust formula Percent Oreen Wclsht--Percent of green weight of crabgrass foliage gn tions. However, these materials usually have a size in the growth on basis or green weight or foliage in the clrecb pots. order of from 2 to 40 microns in diameter (with the aver The percent control demonstrates synergism between age size being from 6 to 8 microns) and therefore arc the phenylmercuric and N-I-naphthyl pbtbalamic acid. prone to release dust when applied. Some of tbe above Growth in the combination treatment is only 2.85% of materials such as talc and fuller's earth have also been that in the check. Growth in tbe separate phenylmercuric 65 found to adsorb polybydric alcohols and aliphatic and treatment is more than 3 times as great and in the aromatic hydrocarbons; however, none of these materials "Alanap" treatment more than 5 times as great as in the will retain such vehicles and active herbicide ingredients combination treatment. This is an important aspect in to the desirable degree to which they are retained by ver the prc-cmergence treatment series in which repeat treat miculite and still provide a dry, dust-free, lighter weight, ments will either kill or further inhibit the affected plants free-flowing, granular composition. Prior dry herbicides which develop from seeds not controlled in the process made with these carriers have not been dust-free nor long of germinating. acting, and have had the problems and shortcomings of In addition to being useful as herbicides, the phenyl- prior dry fomulations discussed above. mercurics arc also effective as fungicides, though the In an effort to determine the processes or mechanics synergism observed in their use as herbicides docs not 75 of herbicidal retention of the herbicidal compositions by 3,083,089 11 12 . vermiculite, numerous leaching studies were conducted. What is claimed and desired to be secured by United For example, when samples of a phcnytmercuric-polyhy- States Letters Patent is: dric alcohol-vermiculite formulation were leached with 1. A free-flowing, granular, substantially dust-free com more than four times the amount of water ordinarily re position of matter comprising a carrier of finely divided quired to completely dissolve the amount of phenylmer- 5 expanded vermiculite particles substantially all of which curie compound combined in the composition, it was pos arc greater than 150 microns in size; a low volatile vehicle sible to extract not more than approximately 20% to and a pesticide which is substantially entirely soluble in 40% of the total phenylmercuric content. Such Cach ings were the result of a single dissolution interval of 20 said vehicle, said pesticide and vehicle being adsorbed on the surfaces of said vermiculite to the substantial exclu to 30 minutes with subsequent filtering of the solution 10 sion of absorbed pesticide, with said pesticide present in from the vermiculite composition. These results indicate a toxic amount; said pesticide being releasable from said that the phenylmercuric was tightly held -by the vermicu vermiculite carrier by moisture. lite particles against the solvent and mechanical washing 2. The composition of claim 1 wherein said pesticide action of water. Also, it was found that repeated teach is at least one member of the group consisting of chlor- ings yielded additional quantities of the phenylmercuric 15 dane, [l-n-butyl-3 - (3,4*dichlorophenyi)-l-methylurea], indicating that it would be available as a toxicant over an pcntachlorophenol, hexachloroacetonc and the phytocidal extended period of time. esters of haloaryloxy-substituted aliphatic acids. Further data obtained in leaching studies of the phenyl 3. The composition of claim' 2 wherein said vehicle mercuric radical combined with vermiculite indicate that is selected from the group consisting of petroleum frac an equilibrium concentration develops between the phenyl- 20 tions having a boiling range of approximately 300 to mercuric radical on the vermiculite platelet and in solu 600 F. tion with the leaching water. The addition of cations 4. The composition of claim 3 wherein said vehicle is and chelating substances in the leaching water shifts the a low molecular weight petroleum naphtha within a boil equilibrium in favor of the solution, probably by causing ing range of 310 to 595 F., with a low aromatic content exchange of the cation with the phenylmercuric ion 25 of no more than 159& by weight of said vehicle. bonded on the vermiculite and by the greater force of at 5. The composition of claim 1 wherein said pesticide traction of chelating substances for the phenylmercuric is at least one member of the group consisting of phenyl ion. Studies with extracts of crabgrass and other plants mercuric compounds, haloaryloxy-substituted aliphatic indicated that these substances facilitate the leaching of acids, [disodium-3, 6-endoxohcxahydrophthalic acid], iso phenylmercuric combinations when added to the leach 30 propyl phenylcarbamate, chloroisopropyl phenylcarba- ing water. This would indicate that the plant in itself mate, [2,4,6-trichlorobenzoic acid], trichloroacetic acid, may contribute to the release of the phenylmercuric radi [2,2-dichloropropionic acid] and [2,4,5-trichlorophenyl- cal from the vermiculite. The dry freejflowing substantially dust-free formula tions of this invention are easily spread onto and retained by the wide leaf and growth of the undesirable weeds and yet are not retained by the turf grasses. The term "weed" as used herein is defined as a plant out of place; thus if clover is not wanted in a lawn, it is classified as a weed. The compositions in the form disclosed herein remain in contact with the plant for substantial periods of time, thereby resulting in the maintenance of a high level of toxic material in intimate association with the plant to furnish the necessary killing action. With the use of the new and novel compositions of this invention the effec tiveness of herbicidal compounds lias been greatly in creased, as compared to dusts or sprays, without serious damage to the surrounding turf grasses. Furthermore, the present formulations are relatively 35 10 15 acetic acid]. 6. The composition of claim 5 wherein said vehicle is selected from the group of substantially water soluble organic vehicles consisting of polyhydric alcohols, lower aliphatic glycol ethers and aliphatic ketones. 7. The composition of claim 1 wherein said vehicle is selected from the group consisting of petroleum fractions having a boiling range of approximately 300 to 600 F. 8. The composition of claim 1 wherein said vehicle is selected from the group of substantially water soluble organic vehicles consisting of polyhydric alcohols, lower aliphatic glycol ethers and aliphatic ketones. 9. The composition of claim 1 additionally comprising a surface active agent in an amount sufficient to increase the phytocidal effectiveness of said pesticide. 10. A free-flowing, granular, substantially dust-frec non-hazardous due to the low concentration of herbicidal compounds and the physical and chemical characteristics 00 composition of matter comprising a carrier of finely divided expanded vermiculite particles having a platelet of the granular vermiculite carrier. They accordingly structure, substantially all of which particles are greater lend themselves readily to treatment of undesirable plant than 150 microns in size; a low volatile organic vehicle; growths by home owners without the need for protective and a pesticide which is substantially entirely soluble in clothing and careful precautions in application. As aforcindicated, this application is a continuation-in 50 said vehicle, substantially all of said pesticide and vehicle being adhered as a thin layer on said platelet surfaces of part of several of applicants copendiftg applications. said vermiculite particles, with said pesticide present in a While much of the material set forth in the specifications. toxic amount; said pesticide being releasable from said of those applications has been expressly incorporated in this application, portions of those specifications have been 60 vermiculite carrier by moisture. 11. A . free-flowing, granular, substantially composition of matter comprising a carrier dust-frec of finely omitted, for the sake of clarity and succinctness. . It is divided expanded vermiculite particles substantially all of to be understood, however, that everything disclosed in which are greater in size than 100 mesh U-S. Sieve; a those applications, insofar as germane to the instant dis liquid pesticide adsorbed on the surfaces of said ver closure, is hereby application. incorporated by reference into this CO miculite particles to the substantial exclusion of absorbed pesticide, in a toxic amount; said pesticide being releas The invention may be embodied in other specific forms able from said carrier by moisture. without departing from the spirit or essentia] character 12. The composition of claim II additionally compris istics thereof. The present embodiments are therefore to ing a surface active agent in an amount sufficient to be considered in all respects as illustrative and not re strictive, the scope of the invention being indicated by the 70 increase the phytocidal effectiveness of said pesticide. 13. The composition of claim 11 wherein said pesticide appended claims rather than by the foregoing description, is at least one member of the group consisting of chlor- and all changes which come within the meaning and range dane, [l-n-butyl-3-(3,4-dichlorophenyl] - 1 -methylnrea], of equivalency of the claims are therefore intended to be pcntachlorophenol, hexachloroacetonc and the phytocidal embraced therein. 75 esters of haloaryloxy-substituted aliphatic acids. 3,083,089 13 14 14. The composition of claim 11 wherein said pesticide to be toxic to said weeds, said pesticide being releasable is at least one member of the group consisting of phenylmercuric compounds, haloaryloxy-substituted aliphatic from said carrier by moisture. ` 18. A method of making a free-flowing, granular, sub acids, fdisodium-3,6-endoxohexabydrophthafic acid], iso stantially dust-free pesticide composition of matter com- propyl phenylcarbamate, chloroisopropyl phenylcarbnm- 5 prising the steps of: dissolving a pesticide in a low volatile ate, [2,4,6-trichforobenzoic acid], trichloroacetic acid, vehicle, and dispersing the resulting solution uniformly [2,2-dichloropropionic acid] and [2,4,5-trichlorophenyl- over expanded vermiculite particles substantially all of acetic acid]. which are greater than 150 microns in diameter, said 15. The composition of claim 11 wherein said pesticide pesticide compound being appiied to said vermiculite is a pbenylmercuric compound and further comprising 10 particles in an amount sufficient to be toxic to selected N-l-naphthyl phthalamic acid in an amount at least suf ficient to increase the pesticidal effectiveness of said phenylmercuric compound. plants and being releasable from said vermicutite by mois ture, the relative quantities of the ingredients being such that said pesticide is substantially adsorbed on the surfaces Id. A method of destroying noxious weeds comprising of said vermiculite particles to the substantial exclusion of applying to said weeds a sufficient quantity to be toxic 15 absorbed pesticide. to said weeds of a free-flowing, granular, substantially 19. A composition of matter comprising as essential dust-free composition of matter comprising a carrier of ingredients a granular, finely divided expanded vermiculite finely divided expanded vermiculite particles substantially carrier having a platelet structure, substantially alt of said all of which are greater than 150 microns in size, with vermiculite being greater than 150 microns in size; phenyl- a pesticide adsorbed on the surfaces of said vermiculite particles, to the substantial exclusion of absorbed pesti cide, said pesticide being present in an amount sufficient 20 mercuric acetate; a polyhydric alcohol vehicle for said phenylmercuric acetate, and N-J-naphthyl phthalamic acid in an amount at least sufficient to increase the effec tiveness of said phenylmercuric acetate, said phenylmer- to be toxic to said weeds, said pesticide being releasable curie acetate being bonded substantially by adsorption to from said vermiculite particles by moisture after it has 25 the platelets of the vermiculite. been applied to said weeds. 17. A method of destroying noxious weeds comprising References Cited in the file of this patent applying to said weeds a sufficient quantity to be toxic to said weeds of a free-flowing, granular, substantially dustfree composition of matter comprising a carrier of finely 30 divided expanded vermiculite partictes substantially all of which are greater than 150 microns in size, a low vola tile organic vehicle; and a pesticide which is substantially entirely soluble in said vehicle, said vehicle and pesticide ,, being adhered as a thin film on said vermiculite particle UNITED STATES PATENTS 1,972,390 2,317,765 2,394,916 2,403,435 2,416.259 2,642,354 2.875.119 Miner ....................................Sept. 4, 1934 HesterApr. 27, 1943 Jones..................................... Feb. 12, 1946 HammerJuly 9, 1946 Kagy ........................... Feb. 18, 1947 RarronsJune 16, 1953 Trademan et al.___________ Feb. 24, 1959 surfaces with said pesticide present fn an amount sufficient 2.875.120 Trademan et al..................... Feb. 24, 1959