CA1154189A

CA1154189A - In-flight encapsulaton of particles

Info

Publication number: CA1154189A
Application number: CA000329395A
Authority: CA
Inventors: Nathan F. Cardarelli; Chester M. Himel
Original assignee: University of Georgia; Environmental Chemicals Inc
Current assignee: University of Georgia; Environmental Chemicals Inc
Priority date: 1978-07-05
Filing date: 1979-06-08
Publication date: 1983-09-20
Also published as: FR2430259B1; JPS5592136A; AU4824679A; FR2430259A1; AU526762B2

Abstract

ABSTRACT OF THE DISCLOSURE

A method and composition for the in-flight encapsula-tion or particles such as insecticides, herbicides, mollusci-cides, acaricides, fungicides, nutrients, pheromenes, odorants, fragrances, attractants, repellants, trace elements, and the like. The composition comprises, by weight, from 1 to 40 per-cent of said particles, from 0.3 to 25 percent of a film-forming polymer and from 35 to 99 percent of a solvent which renders said polymers soluble. Often, other compounds may be added to impart desirable properties such as a second film-forming poly-mer, crosslinking agents, film modifying agents, and adhesives to improve adhesion to a target. The particle may be in a true solution suspended or emulsified through the action of sur-factants and/or emulsifying agents. The film-forming polymer is selected from the class consisting of polyvinyl ethers, polyvinyl acetate, and interpolymers of alpha-beta olefinically unsaturated carboxylic acids and N-methylol acrylic amides, a-set forth in U. S. Patent No. 3,007,887. Upon ejection from a spray apparatus and during flight through the intervening atmosphere, the solution rapidly loses the solvent component via evaporation, coacervation occurs, and a polymeric membrane forms about the particle. Control of the encapsulated particle size can be achieved through selection of the spray system and of the non-volatiles in the spray at the moment of droplet formation.

Description

BACKGROUND OF THE INVr,MTlON

The present invention relates to a composition of a self-encapsulating polymeric-containing solution and a process for the in-flight encapsulation of particles such as insecti-cides, fungicides, herbicides, etc., contained therein. More specifically, the present invention relates to the in-flight encapsulation of said particles during passage between the egress of a spray apparatus and a target.
Heretofore, the encapsulation of a chemical substance within an enveloping polymericl~membrane has been well recogni~ed by the art. For example, U. S. Patent Nos~ 3l242,051, 3,255,629, 3,575,882, and 3,607,776 all relate to processes dependent upon phase sepaxation and polycondensation reactions. Specifi-cally, he 3,24~,Q51 patent relat~s to preparing a solution of a liquid phase-forming mlcromolecular polymer in a first non-aqueous liquid, dispersing in said solution a plurality of individual discreet particles, adding a second liquid soluble in the fl~st liquid, but not soluble with regard to said micro-molecular polymer, whereby phase separation is induced and pre-coats the dispersed partic1es, settling the polymer-rich precoat, separating the precoated particles, suspendlng the precoated particles in an aqueous solution of a gel, and using phase separation so as to cause the formation of a colloidal-enriched phase and the encapsulation of each of these suspended precoated particles, and cooling.
U. S. Patent No. 3,265,629 is similar but rela-tes to the app1ication of two~coatings to the par~icles, namely a solid lipid and a polymer.

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U~ Sl Pa~ent No~ 2J 648,6.Q9 relates to an air suspension t~chni.que wherein a sugar solution ls sprayed onto a ~uspended i.t'em such. as ca:ndy, gum, etc~ Another techniqu~ h~ret,ofore utilized is the' utilization of charging a first solution with ions so that the solution exhibits a specific charge, applying an opposi.te charge to a second solution, and then coatin~ the firs~ solution with the second solution vi.a air, flow~
U, S~ Pat~nt No~ 3,2Q2?533 relate6 to the encapsu-lation of liquids by the use o~ a flui.dized bed wh.erein the fluidized liqui.d is frozen and spray coated.
' Com~on to all such above-described inventions and : prior art processes is the utilization of multiple ~compounds or composi~ions of matter as wel'l as the necessity of pro-cessLng t~e'encapsulated or micro-encapsulated article prior to usage or appli.cation~ Moreover, costly and complex pro-cessing equipment as well as dif~icult tec~nology is required `~ to produce'articles' of a defined size and to meet mandatory .~. environmental controls or regulations, ~ In contrast~ the present invention relates to but -~ a single self-encapsulating polymeric containing solution.
~: Moreover~ the invention pertains to encapsulation of a ' particle phase via a polymer through. in-flight encapsulation;
that is, during the passage from the spraying or ejection ;~ : equ~pment to the target substance'or area, including an agricultural ox forested area.
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''SUMMARY'OF'TH~'IN~ENTIO~
It ls, thereforé, an obj'ect of t'he present inven-. ~ .
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tion to provide a composi.ti.on and process for the i.n-fligh.t encapsulation of particles.
It is another obj ect of the present invention to provide for the in-flight encapsula-tion of particles, as above, wherein said composition comprises generally a ~ilm-forming polymer in a solvent system for solubilizing said polymer~ and any desired particles wh.ich may be soluble or dispersed in the solvent medium~
It is a further object of the present i.nvention to provide for the in-flight encapsulation of particles, as above, wherei:n upon eje.ction from a spray apparatus and during fli.ght t.hrough th.e intervening earth's atmosphere, the solution rapi.dly loses the solvent component through evaporation with'coacervation occurring and resulting in the formati.on of a polymer membrane about the particle~..
It is a further object of thè present invention to provi.de'for th.e in-flight encapsulation of particles, as:above, wherein said particle is encapsulated by said polymer upon the .evaporation of some or most, if not all, of the solvent in the process of passage of said particle between an ejector or a spray apparatus and a target.
: . It is an additi.onal object of the present inven-tion to provide for the in-flight encapsulation of par~icles, as above, wherein said particles are very s~all so that a micro-encapsulated product is produced~
It is a still furthe:r object of the present inven-tion to provi.de for the in-fli.ght encapsulation of parti.cles, as above~ wherei'n said encapsulated product is of fairly " ~, uniformed particle size~

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It is a still further object o~ the present in vention to provide for the in-flight encapsulation of particles, as above, w~erein an outer polymer me~brane exists about an inner particle core.

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- It is a still additional objec-t of the present inven-tion to provide for the in-flignt encapsulation o particles, as above, wherein, due lar~ely to the uniform product size, ; target specificity can be incorporated into the in~flight system.
It is yet another object of the present invention ` to provide for the in-flight encapsulation of particles, as above, wherein said encapsulated particle can be insecticides, acaricides r fungicides, herbicides, nutrients, trace minerals, nematicides, molluscicides, pheromenes f odorants, fragrances, lQ attractan s, repellants, and any other desired particle.
It is yet another obj~ct of the present invention to provide for the in-flight encapsulation of particles, as above, wherein the leaching of said particle on a target ins~ead of occurring in a matter of minutes or hours can range from a day to a period of months.
It is yet another object of ~he present invention to provide for the in-flight encapsulation of particles, as above, wherein crosslinking agents may be added to said solution to control the leaching time period.
It is yet another object of the present invention to provide for the in-flight encapsulation of particlesl as above, wherein various adhesive and film-modifying agents may be added to said solution so that improved adhesion of said encapsulated product to said target occurs.
These and other objects of the present invention will become apparent from the following preferred embodiment of the invention.

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In general, a process in accordance with the inven-tion for the in situ encapsulation of particles between a spraying apparatus and an earth target, is characterized by: preparing a self-encapsulating polymeric-containing solution, said solution comprising by weight from about 0.3 percent to about 25 percent of a film-forming polymer, from about 35 percent to about 99 percent of a solvent, said solvent being a compound which will solubilize said polymer, and from about 1 percent to about 40 percent of the particles, said particle being soluble or dispersible in said solvent; in situ encapsulating said soluble or dispersible particle by: spraying into the earth's atmosphere said solution containing said soluble or dispersible particle from a spray apparatus, and immediately thereafter;
evaporating said solvent in said earth's atmosphere, and coacervating during the passage from said spraying apparatus to an earth target said polymer and said particle in said earth's atmosphere so that said polymer substantially encapsulates said particle, and concurren~ly and directly applying said encapsulated particle to an earth target.
Generally, an in situ self-encapsulating polymeric-containing solution for concurrent and direct application to an earth target, is characterized in that, based upon the total weight of said solution, said weight ranges from about 0.3 percent to about 25 percent of a film-formiIIg polymer, from about 35 percent to about 99 percent of a solvent, and from about 1 percent to about ~0 percent of a particle, said particle being soluble or dispersible in said solvent; said solvent being a c-ompound in which said polymer is soluble; and a small amount by weight based upon the total weight of '.

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the solution of an adhesive agent to that upon the in situ formation of an encapsulated partiele from said solution and the concurrent and direct application of said encapsulated particle to an earth target, said adhesive agent improves the taekiness of said encapsulated particle to said target.
Additionally, an encapsulated partiele having been in situ eneapsulated and coneurrently and direetly adhered to an earth target, is characterized by a particle, said particle encapsulated with a film forming polymer; and said particle having been in situ eneapsulated and eoneurrently and direetly applied to the earth target; said eneapsulated particle eontaining a small amount of an adhesive agent so -that said eneapsulated partiele has improved tackiness and adheres to sàid earth target.

IN THE DR WINGS

Fig. l is a photograph of an eneapsulated partiele, aeeording to the present invention, wherein a polymerie film is shown about the particle and the film is adhered to a glass strand;
Fig. 2 is a photograph similar to Fig. l wherein the eneapsulated partiele is adhered to the junetion of two glass strands;
Fig. 3 is another photograph showing a particle polymerieally encapsulated about a glass strand; and Fig. 4 is another photograph showing an eneapsulated par-ticle attaehed to the interseetion of two glass strands.

~' .' ' ."`' , . ~ , PREF~RR~D EMBODIM~N~. O~ Th~ INV~TION

The concepts of th.e present invention relate to a compo~i.tion and process with regard to the in-~light encapsu-la~ion of particles. Numerous applications exist through conventional ejection equipment such as conventional spray-ing apparatus to apply encapsulated particles for various utilities, for example, public health protection, agricul-tural applications, and any other area or field in which the encapsulation of particles, especially micro-encapsulation, is desired. By the term "in-flight encapsulation" it is meant that the particle is covered, surrounded, coated, or encapsulate.d by a film-forming polymer by a coacervation process during or between th.e passage from an ejector or a spraying apparatus to a desired target, material, area, or the like. Moreoverl the encapsulated material of the present invention results in a controlled release of the particle through a leaching mechanism so that in effect a slow release of the particle is achieved from a matter of a day or two to several weeks or months~ :
The self-encapsulating polymeric-containing solu-tion comprises a film-forming polymer in a solvent in which the polymer is-soluble, and the parti.cle itself, Therefore, the polymeric-containing solution exists as a particle. either dissolved or dispersed in the solvent-polymer phase, At times, a three-phase system can be used in which the solvent constitutes the third phaseO On a weight basis, the total amount of polymer u~ilized ranges from , . ~ , ,:, . . . . .

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about 0.3 percent to about ~5 percent, with from about 2 to ahout 18 p~rcent heing desirable, and from 4 to 13 percent being preferred. Often times, insteacl of a single film-forming polymer, two or even three types of polymers can be utilized. The amo~nt o~ solvent ranges from about 35 percent to about 99 percent with rom about 50 to about 90 being preferred. The amount of ¦I particle ranges from about 1 percent to about 40 percent with Il from about 5 to about 30 percent being preferred. ~Jaturally, as ¦I will be better understood by referring to the examples in the 10 I specification, the various components or compounds can be varied j to achieve specific changes in properties of the ~inal product;
¦ that is, the encapsulated particle. Additionally, various ¦¦ adhesive agents, crosslinking agents, emulsifying agents, and Il other additives may be added to further modiy either the pro-cess or the end product properties~
Suitable polymers for use in the present inventionrelate to film-forming polymers which are capable of encapsu-lating the particle by coacervation and which form a polymeric film about the particle. Such a specific polymer is polyvinyl 20 !j acetate having a molecular weight range of from about 10,000 ¦I to about 100,000. Another suitable and desired polymer is th~
¦I polyvinyl e~hers wherein the repeating hydrocar~on group i5 an l alkyl havi~g from 2 to 10 carbon atoms, preferably 2 carbon ! atoms, and w:ith the polymer having a molecular weight of from 25~ about 10,000 to about 100,000.
¦ A yreferred polymer of the present invention relates to j carboxyla~ed acrylic polymers and copolymers such as those made 1~ .

from monomers having the formula H2C= C C OR4 where R4 is a hydrogen radical or a hydrocarbon group having from 1 to 30 carbon atoms and R5 is a hydrogen, radical or a hydrocarbon group having ~rom 1 to 12 carbon atoms~ both hydrocarbon groups selected from the class consisting of alkyl, cycloalkyl, aryl, and aralkyl. Desirably, R4 is an alkyl having from 1 to 4 carbon atoms and preferably is hydrogen. R5, 10 desirably, has from 1 to 3 carbon atoms and, preferably, either has 1 carbon atom or is hydrogen. By carboxylated, it is meant that a substantial number of the pendant groups of the polyacrylate contains carboxyl groups. Moreover, by copolymers, it is meant that the polymer may be made from 2 or more monomers having the above formulation. A preferred polymer is made from methacrylate monomers with a preferred polymer being made from acrylic acid monomers. The molecular weight of the carboxylated acrylic polymers generally ranges from 10,000 to 600,000 with a preferred range being from about 30,000 to about 300,000.
A highly preferred polymeric compound of the present invention is the salts of interpolymers of alpha-beta olefinically unsaturated carbonyl monomers which contain N-methylol acrylic amides as set forth in U.S. Patent No.
3,007,887. Generally, the interpolymer has the following structure: -. ...

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_ C112 C -- ` --¦ CH2~ C ~ -~'H2_ CH----_--CH2 r C ~ _ C ~ C C-- _ C~2 OR3 C~O X X

where R and Rl are members of the group consisting of hydro~
gen and methyl; R2 is a member of the group consisting of methyl, ethyl, propyl and butyl; R~ is a member of the group consisting of methyl and ethyl; n represents from 3 to 12 weight percent based on the combined weight of n, x, y and z;
x represents from 8 to 25 weight percent based on the com-bined weight of n, x, y and z; y represents from 45 to 89 wei.ght percent based on the combined weight of n, x, y and z;
z represents from O to 44 weight percent based on the com-bined we:ight of n, x, y and z; the sum of the numerical value of n + x + y + z is always exactly 100 and the groups n, x, y and z are present in a heterogeneous relative position.
The interpolymer is converted fro~ an alcohol solution to water solutions by the addition of water having neutralizing agents such as ammonia, a hydrazine, or a low-boiling amine to the alcoholic solution of the interpolymer followed by ~n azeotropi.c di.stillation which removes th.e last traces of the alcohol and~the excess neutralizing agent. The final aqueous soluti.on of the polymer sal~ is preferably in the range of pH 5-8 and more pre~erab~ly in the range of pH 6-7 with a total soli.ds con~ent of from about 2 to 40 percent by weight and preferably ~rom about 5 to about 30 percent by weight of polymer in water.

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The polymers embodied in this invention are those compositi.ons comprising from 45 to 89 parts by weight o~ a low~r acr~lic acid ester, ~rom O:to 44 parts by weight of a lower me.~hacrylic acid ester, from 3 to 12 parts by weig'nt of an alpha-beta olefinically unsaturated carboxylic acid having a terminal CH2- C < group and having from 3 to 4 carbon atoms and from 8 to 25 parts by weight of an N-meth~lol alpha-beta olefinically unsaturated carboxylic acid amide having a terminal CH2 - C< group and having from 4 to 5 carbon. atoms.
The lower acrylic acid esters useful in this in-vention include those in which R2 in th~ above formula is an aliphatic . . . ~ . ~ . . . . . . . . . . . . . . . . .

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¦¦ hydrocarbon group having from 1 to 4 carbon atoms such as ¦ methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate~ n-butyl acrylate, isobutyl acrylate and secondary ! hutyl acrylate. The most preferred lower acrylic acid esters 5 ¦ are methyl acrylate and ethyl acrylate~ The lower acrylate ¦¦ acid esters are useful in the range o fxom about 45 to about ~1 89 weight percent based on the weight of the other monomers.
il The lower methacrylic acid esters usefui in this ¦1 invention include those in which R3 in the above formula is 10 ijl an aliphatic hydrocarbon group having from 1 to 2 carbon atoms i! such as methyl methacrylate and ethyl methacrylate. The pre-I ferred methacrylic acid ester is methyl methacrylate. The ¦j lower methacrylic acid esters-are use~ul in the range of from ¦~ about 0 to about 44 weight percent based on the weight of lS I the otner monomers.
I The alpha-beta olefinically unsaturated carboxylic ¦~ acids embodied in this invention include ~crylic acid and il methacrylic acid. The alpha-beta olefinica~ly unsaturated ¦¦ carboxylic acids are useful in the range o from about 3 to 20 ¦¦ about 12 weight percent based on the weight of the other mono-¦l mers.
Il The N-methylol acrylic amides embodied in this in-¦ vention include N-methylol acrylamide and N-methylol methacryl-l amide. The most preferred N-methylol acrylic amide is N-methvlol 251 acrylamide. The N-methylol acrylic amides are useful in the range of from about 8 to about ~5 wei~ht percent based on the weight of the other monomers.

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The molecular wei,ght of the polymer represented by the above interpol~mer structure generally ranges from about 20,000 to about 1,000,000, with a weight of from about 307000 to about 250,000 being preferred~
Specific examples of the above interpolymers in-clude Carboset XLll (molecular weight of about 45,000), Carboset 514 (molecular weight of about 30,000), Carboset 515 (molecular weight of about 70,000), Carboset 525 (molecu-lar weight of 300,000), all manufactured by the B. Fo Good-rich Company, Generally, the higher the identification number, the~higher the molecular weight of the particular interpolymer~
The solvent may be any solvent which will solubilize the above polymers. Generally, water and alkanols having from 1 to 5 carbon atoms, and combinations thereof, may be utilized, Examples of speci~ic alcohols include methanol, propanol, isopropanol, bucanol, isobutanol, pentanol, e~c., with e~hanol being preferredO Other suitable solvents in-clude acetone, diisobutyl ketone, methyl e~hyl ketone, dioxane, and ~ethylene chloride. Moreover, other solvents may be used in which the particle is generally soluble or emulsifiable therein.
The particle is usually a solid. However, in some instances, the particle can be a liquid. Regardless of whether the particle is a solid or a liquid, it can be any compound which, as part of the self-encapsulating solution can be ejected or sprayed by either known or conventional ejecting or spraying apparatus. . . .

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Although the particles may be of any siæe ~o long as they can be sprayed or ejected by an apparatus, they ~re desirably small to facilitate in the ease of ejecting or spraying the solution or, generally, due to their nature of application.
5 ~ For example, at least 90 percent of the particles having a size ranging frorn less than 1 micxon to 200 may be utilized, althou~n, generally, they are from a much smaller range a~ from about 1 . to about lOQ microns. For insecticides, odorants; etc., the , application of particles smaller than 100 micron~, as from 1 10 ` to 50 microns, are preferred.
Naturally, it is desirable that the particle, the solvent, and the polymer be compatible with each other in that !~ . .
they lack chemical interaction.
~ The particle compounds include nutrients such as fe~tili2ers or vit~l trace minerals, insecticides, acari~ides, nematicides, molluscicides, herbicides, fungicides, phe~omenes, odorants, fragrances, attractants, repellants, and innocuous materials for scientific effort, keyed to elucidating spray !i Pquipment design, spray effects depending upon environmental 20 ! infIuences, and the like, or other materials where rapid and l~ controlled delivery to a given target is desired. Specif i c examples of these classes of particles are set forth below.

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Trace Nutrients 25~ 2inc chloride Boric acid ,; Zinc sulfate Sodium borate erric chloride Sodium selenate Ferric sulfate Cobalt sulfate Copper sulfate Sodium molybdate Coppex oxychloride Manganese chloride 'I 5, !
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; Insecticides and Acar1cides O,O-diethyl-O-p-nitrophenyl phosphorothioat~ ~Parathion) : O,O-dimethyl-O-p-nitrophenyl phosphoro-thioate (Methyl parathion) O,O-dimethyl-0-(3-me~hyl-4-nitrophenyl)phosphorothioate : ~Sumithion) O,O-diethyl-O-(2-isopropyl-6-methyl-5-pyrimidinyl) phosphorothioate I (Diazinon) 5 ! O,O-dimethyl-O-[3-methyl-4-(methylthio)phenyl]phosphorothioate (Fenthion ) j. Pyrethrin-piperonyl butoxide . I
Ij l-naphthyl methyicarbamate (Carbaryl) i~ 2-(1-methylethoxy)phenol methylcarbamate (Baygon, manufactured `, by Chemagro

2-methyl-2-(me-thylthio)propionaldehyde-O-(methyl carbamoyl) i! oxime (Aldicarb, manufactured by Union Carbide) ~' S-methyl N-[methylcarbamoyl(oxy)] thioacetamide (lannate) 1, Chlorinated cam~phene, 67 percent Octachlorocamphene (~oxaphenev 10 ~ manufactured by Hercules) : Tricalcium aresenat~o - Sodium aluminum fluoride Dichlorodiphenyltrichloroethane Tricyclohe~yltin hydroxide (Plictran, manufactured by Dow Chemical) ;. .
Nematicides G,O-diethyl-0-2,4-dichlorophenyl phosph.orothioate(dichlofenthion) O-Ethyl S,S-dipropyl phosphorodithioate (~thoprop) Molluscicides .
. Copper sulfate Trihutyltin 1uoride : n-tritylmorpholine (trifenmorph) Sodium pentachlorophenate Herbicides 2,4-dichlorophenoxyacetic acid (2,4-D) Alkylamine salts of 2,4-D
.. Buto~yethanol ester of 2,4-D
, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T~
, ~-(2,4,5-trichlorophenoxy)propionic acid (Silvex) : 3~amino-2,5-dlchlorobenzoic acid (chloramben) ~; 3,6-dichloro-O-anisic acid (Dicamba) 2,3,6-trichlorophenylacetic acid (Fenac) 2,6-dichlorobenzonitrile ~Dichlobenil) 25 ~ N,N-diallyl-2-chloroacetamide (Randox) :'. S-Ethyl diisobutylthiocarbamate (Sutan~
Isopropyl N-(3-chlo,ophenyl) carbamate (chloropropham)

3-amino-1,2,4-triazole (Amitrole) 2-chloro-4,6-~is(ethylamirlo)-S-tria~ine (Simazine) , 2 chloro-4 ethylamino-6-isopropylamino-S-triazine ~Atrazine) 1 ~, i . .,~: ~. !

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_n~icides . .
~riphenyltin acetate Methyl~ butacarbamoyl)-2-benzimidazole carbamate (Benomyl) The self-encapsulating polymeric-containing solution of the present invention is applied by ejecting or spraying a liquid solution or emulsion from known or con~entional spray ; equipment~ Such spray equipment can be ~ffixed to any suitable vehicle such as an aircraft, truck, a spray system in a field, ~ and the like, utilizing ~echniques and artiices common to the particular art, for example, as in the agricultural and public health areas. Subsequently and im~ediately after ejec-tion, the spray during flight through the intervening atmosphere rapidly loses solvent via evaporatlon, coacervation occurs, and small solid spheres are forme~ having generally a very uniformed shape and 5' ~e . Th~ls, ini-fliaht encapsulation occurs during the short passage between the egress oi a spray o~r ' ejection appa-atus and a target area with the deli~ered encapsu-lated product being a solid. Each sphere or microcapsule ~ is comprised of an outer enveloping polymeric membrane and an inner core of the particle or an agglomera~ior. of particles.
~ The encapsulated product can be delivered to and within the ,` target area using narrow spectrum sprays ~for example, tha~ pro-duced by the Beeco Mist Noz21e, designed to provide a sufficient ~
1 transport o~ the active ingredient to its targe~ area). ~en- !
25 i erally, the various spray systems can be adjusted such that a ~; few ounces o~ the composition or solution is utilized ~or each ,; acre or up to about 2 to 5 gallons of solution per acre. In the latter case, water is generally utilized as a solvent. I
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' li541t39 ¦ Moreover, applicants' composition, solution and process, aided by the film-forming polymer coating of a particle ¦ or particles, can result in fairly uniform sizad encapsulated l products, that i~, encapsulated products in which at least 90 5 ¦ percent of the products fall within a narrow ran~e, and as set ¦ forth hereinabove Of course the size of the encapsulated pro-ducts can be varied by changing the proportion of the various I ingredients, the amount of crosslinking agent, and the like, ¦ as set forth hereinbelow as well as utilizing different spray 10 ¦ equipment, particularly the nozzles thereon which largely ¦ determine the initial egress droplet size spectrum. Thus, ¦ encapsulated products having a particle size of from micron to ¦ 500 microns or larger can be produced. Generally, however, ¦ encapsulated products of from about 1 to about 100 microns are desired for many applications. A specific example of a suitable I
¦ spraying apparatus which delivers droplets over a narrow range ¦ is manufactured by the Beeco Products Corporation. As a xough rule of thumb, the encapsulated particle size will be 80 percent of the initial droplet size leaving a spray or eject-ing apparatus, when the amount of solvent is equal to the amount ¦¦ of particles on a weight basis. Since great uniormity and ¦ droplet size as well as the encapsulated product can be con ¦ trollea as described herein, the microcapsules of the present ¦ invention are i~eal as a research tool Eor th~ study and evalua- !
25 ¦ tion of spray equipment and effects of atmospheric parameters upon the spraying art.
Additionally, micro-encapsulated products of the present invention result in a controlled leaching rate of 11541~9 the particular particle at the site of application or target ~area so that the particle availa~ility is greatl~ prolon~ed l and leads to greater efficacy, reduced contamination, and ¦ economic benefit. Also, non-persistent agents can be encapsulated¦
and essentially rendered persistent at the microcapsule applica-tion site, so that once released in the ~nvironment/ it becomes j subject to natural degradation factors so that persistency , is low at the site of application; ayain a positive contribution ~¦ to enhance environmental quality.
I0 ¦¦ In addition to varying the components of the generally ~¦ three-phase system, additional compounds or agents may be il added to the solution to control various parameters or function~
¦¦ such as capsule size, the enveloping polymeric membrane thickness, Il the leaching rate, the rate of evaporation, the emitted droplet 15 ~I size, adhesion, and the like. ~aturally, such additives should not have any chemical interaction which any of the components ~¦ of the system.
ll Generally, the enveloping polymeric membrane of ¦¦ the polymers of the present invention and, particularly, the 20 1l preferred interpolymer have xelatively little environmental 1~ resistance and, thus, the effects of the rain and sun are ¦~ detrimental to the longevity of the particle. However, longevity ¦ can be enhanced in several ways as by increasing the amount ~ or thickness of the enveloping polymer membrane. ~his can 25 ~ be achieved by utilizing a greater ratio of polymer~ Moreover, ¦l longevity can be increased by utilizing specific types of ¦ polymers such as various specific interpolymers which show improved leaching rates over simllar polymers. Cros~linking 1~ 9 l~S~
agents may also be added to the solution so that, upon encapsulation, the polymeric membrane is crosslinked.
Crosslinking decreases the pore size and, hence, increases duration or longevity so ~hat the final particle may be utilized over a period of several months. Suitable cross-linking agents include the alkal.in earth metal salts where-in the alkalin earth is berylli~lm, magnesium, barium or, preferably, calcium. Suitable anions include carbonate, bicarbonate, nitrate, oxide, hydroxide, and the various halogens, for example, F , Cb , I , and Br . Of these, the calcium salts, especially calcium hydroxide, are desira-ble and calcium chloride is preferredO Moreover, the interpolymers may be crosslinked with zinc oxide as taught in U. S, Patent No, 3,749,7720 Generally, the extent of the crosslinking agent may range from about 0.01 to about 005 percent by weight based upon the total weight of the solu-tion with the range of from about 0.05 to about 0.25 being preferred. Naturally, the crosslinking agents should be non-toxic, generally, non-reactive with the components, and soluble in the solvents of the present invention.
The self-encapsulating polymeric-containing solu-tion of the present invention, generally, must be maintained in relatively a non-acidic state, usually at a pH of 6.5 to 8~0, to prevent crosslinking prior to solvent evaporation.
Typical alkaline agents may be utilized to achieve such a pH range, such as ammonia, sodium hydroxide, and the like.
~lormally, only very small amounts are required as on the range of 0,01 to about 1~0 percent by weight of the total solutionO

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11 541~9 In many applications, especially those involving the delivery of insecticides to protect crops an~ the liXe~, long term adhesion of the microcapsule to foliage or other plant structures is desired. Improved adhesion can be obtained by generally utilizing the lower molecular weight interpolymers and/or adhesive agents such as small amounts of alkyl esters as from 0.01 to 3 percent by weight ~ased upon the total solu~
tion. The alkyl esters a~e of the formula Ri C O R2 where Rl and R2 contain from 2 to 5 carbon atoms with Ethyl acetate being preferred.
Th~ e~fect of the various ingredients upon the membranej thickness, adhesion, longevity of release and the like will 1~ b~ bet~er ~nde~s~ b~ referense to Table I which sets ~orth formulations in Examples 1 through12 In Example 1, the interpolymer utilized was 16 percent of a high molecular type such as Carboset 525, 50 percent by weight of alcohol, and 34 percent by weight of the particle. In Example 1, the particle was actually in solution as a 50-50 mixture of benzoic acid and ortho-toluic acid. This example, as well as ~he other examples were ~prayed through a Beeco Mist spray gun utilizing a 60-micron pore size no~zle. The polymeric film totally encapsulated the crystallized acids used as a particle and the encapsulated product were spheres. Example 2 illustrates a crosslinked version of Example 1 wherein calcium chloride was used as a crosslinking agent along with a small amount o ammonia to prévent premature crosslin~ing prior to solvent evaporation.

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The thickness of the polymer membrane was greater than that of Example 1~ Decreasin~ the average molecular weight of the polymer com~ponent as in Example 3 decreases the membrane or wall thickness and, thus~ lowers the field li.fe of the capsule~ For long life, that is from abou~ 3 to 6 months, the polymer of Example 4 may be crosslinked as shown in Example 5~
As previously noted, the use of low mo]ecular weight polymers provide some degree of tackiness so that the encapsulated product will adhere to leaves, ste~s, and the like. However, since lower molecular weight polymers are often diliteri.ous to film-forming properties, increased adhesion time of several weeks and even several months can be obtained by adding small amounts of ethyl acetate or butyl cellosolve, as set forth in the formulation of Example 6~
The process of adhesion promotion is as follows~ Utilizing the formulation of E~ample 7, the microcapsule forms and crosslinking occurs, as soon as -the alcohol and ammonia evaporate, the process being essentially complete in a few seconds after the egress from a spraying apparatus and also depending upon the droplet surface area. However, the ethyl acetate or butyl cellosolve is occluded by the forming envelope and, t~us, for the most part~ is present at the time of foliage contact~ At the instant of such contact and for several seconds thereafter, the ethyl acetate movçs from the microcapsule, penetrating the outermost dermis of the plant. This process, mainly a desorption phenomenon, results in a slight flow of the polymer envelope into the foliage structure, thus enhancing adhesion~

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The process is rapid and relies on a very minute quality of an ¦l adhesive aid, such as ethyl acetate. Moreover, no damage to agricultural lmportant plants arises from momentary contact l! with the ethyl acetate.
5 1I Water systems and water/alcohol systems have also ¦ been utilized as where the uses of a diluted alcohol would be ad~antageous. Examples 8 and 9 illustxate such systems, ~¦ based upon a water soluble interpolymer, particularly, Carboset li XLII. In Example 8ra pure water system is utilized and, hence, 10 ¦~ the particles are limited to water so~uble compounds. Although !¦ thiC formulation is of poor environmental resistance, it i5 ¦¦ used in delivering trace nutrients such as ~7ater soluble zinc, ¦~ copper, ironf and other sal~s. The formula~ions of Examples ¦~ 8 and 9 result in capsule formation during flight, but due 15 1I to the amou..~ of ~2 ~resent 2~ the t~me of ~m~.ct~ the effects may be a soft capsule t~at flows to meet the contoux of th~
i impingement surface. Rigid spheres are usually not formed.
~I Such systems may also be crosslinked and adhesion promoted I In contrast, the porosity of a microcapsule may be enhanced 20 ¦I by the utillzation of an alcohol insoluble with a water soluble additive such as calcium benzoate, calcium hydroxide, and ! calcium carbonate. Considering Example 10, during in-flight ¦! encapsulation, most of the calcium chloride is trapped within ~¦ a polymer membr~ne. However, once the crosslinked capsule 25 i'~ has adhered to a given surface and comes into contact with ¦ water, the porosigon~ calcium ~enzoate, is rapidly lost through leaching and a pore structure remains allowing water penetration ¦ of the core partlcle. When calcium hydroxide is used as in ~Z3 , ~

¦ Example 11, it not only serves lo crosslink the polymer but also imparts alXalinity and, thus, no ammonia i9 necessary.
Since calcium hydroxide is alcohol soluble, a considerable 1~ fraction is found in the core area. However, sufficient quanti- ¦
5 ¦¦ ties exist within the polymer envelope to enhance the growth !i f porosity 10~

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l The invention will be better unders-tood by reference ¦ to ~he following additional examples.

l ~XAMPLE A
S I A solution con~aining 75 parts by weight of ~Ipyrethrin-piperonyl butoxide, 25 parts by weight of Carboset 5~, ¦land 100 parts by weight of ethanol was made. The solution was mixed and added to a manual spray ejector such as a hand-operated l~atomi~ing pump. The solu~ion was sprayed in the direction of !Iglass fibers located approximately 1 to 2 eet away from the ¦!egress of the spra~ pump. Upon spraying, the Carboset encapsu-jlated the pyrethrin-piperonyl butoxide. The graphic analysis, as shown in photographs 1 through 4, clearly depicts the poly-jmeric ~ilm formed about the pyrethrin-piperonyl butoxide l¦pzrticle. The gl~s~ strands in all ~hotographs are 10 microns in ji~diameterO As apparent from the photographs, Fig. 1 defir.itely ¦jshows a polymer formed about the particlel with the polymer ¦ladhered to a glass strand. In Fig. 2, the polymer is formed ,¦about the intersection of two strands with another encapsulated ¦iparticle located about a single strand. Fig. 3 discloses the ¦encapsulated film being located about the liquid particle. In ¦Ithis photograph, the film actually formed completely about a ¦Iportion of the glass strand. Fig. 4 is similar to Fi~. 2 in that l it reveals a polymeric film formed about the intersection of two 1 glas~ strand~ with a liquid particle being located therein.
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Thirty parts by weight of Carboset XLll having a molecular weight of approximately 45,000 and a 30 percent aqueous ¦
l dispersion was mixed with 100 parts of water. To this was 5 1 added 120 par' 5 of Dursban containing 75 percent of an active jlingredient of O,O~diethyl-O 3,5,6-trichloropyridinylthriono-¦¦phosphate. These ingredients were mixed and the solution had a pH of 6.7. Utilizing a hand spray pump, the soiution was ¦¦sprayed towards a target area. Photographs reveal that the 10 'iactive ingredient was fully encapsulated by the particle.
~¦ While having described the invention in accordance with the patent s~atutes, the invention is measured by the . following claims .
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251j il .

Claims

d The embodiments of the invention in which an ex-clusive property or privilege is claimed are defined as follows:

1. A process for the in situ encapsulation of parti-cles between a spraying apparatus and an earth target, which is characterized by:
preparing a self encapsulating polymeric-containing solution;
said solution comprising by weight from about 0.3 percent to about 25 percent of a film-forming polymer, from about 35 percent to about 99 percent of a solvent, said sol-vent being a compound which will solubilize said polymer, and from about 1 percent to about 40 percent of the particles, earth's said particle being soluble or dispersible in said solvent;
in situ encapsulating said soluble or dispersible particle by:
spraying into the earth's atmosphere said solution containing said soluble or dispersible particle from a spray apparatus, and immediately thereafter;
evaporating said solvent in said earth's atmosphere, and coacervating during the passage from said spraying apparatus to an earth target said polymer and said particle in said earth's atmosphere so that said polymer substantially encapsulates said particle, and concurrently and directly applying said encapsulated particle to an earth target.

2. A process according to Claim 1, wherein said polymer is selected from the class consisting of (a) poly-vinyl acetate; (b) a polyvinyl ether wherein said repeating unit has from 2 to 10 carbon atoms; (c) an acrylic polymer or a copolymer made from monomers having the formula where R4 is hydrogen or an alkyl cycloalkyl, aryl, or aralkyl having from 1 to 30 carbon atoms and R5 is hydrogen or an alkyl, cycloalkyl, aryl, or aralkyl having from 1 to 12 carbon atoms; (d) the salt of (l) an interpolymer having the structure:

wherein R and R1 are members of the group consist-ing of hydrogen and methyl; R2 is a member of the group con-sisting of methyl, ethyl, propyl and butyl; R3 is a member of the group consisting of methyl and ethyl; n represents from 3 to 12 weight percent based on the combined weight of n, x, y and z; x represents from 8 to 25 percent based on the com-bined weight of n, x, y and z; y represents from 45 to 89 weight percent based on the combined weight of n, x, y and z;

z represents from 0 to 44 weight percent based on the com-bined weight of n, x, y and z; the sum of the numerical value of n + x + y + z is always exactly 100 and the groups n, x, y and z are present in a heterogeneous relative position, and (2) a member of the group consisting of ammonia, hydrazine, a low boiling primary aliphatic amine and a low boiling secondary aliphatic amine, said salt being soluble in water in the pH range of from about 5 to 8; and (e) combinations thereof; ' wherein the molecular weight of said polyvinyl acetate ranges from about 10,000 to about 100,000, wherein the molecular weight of said polyvinyl ether ranges from about 10,000 to about 100,000, wherein the molecular weight of said acrylic polymer or copolymer ranges from about 10,000 to about 600,000, and wherein the molecular weight of said interpolymer ranges from about 20,000 to about 1,000,000.

3. A process according to Claim 2, wherein said solvent is selected from the group consisting of alcohols having from I to 5 carbon atoms, acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof.

4. A process according to Claim 2, wherein said particle is selected from the group consisting of an insecti-cidel a trace mineral, an acaricide, a nematicide, a mollusci-cide, a herbicide, a fungicide, a pheromone, an odorant, a fragrance, an attractant, a repellant, and combinations thereof.

5. A process according to Claim 4, wherein said solvent is selected from the group consisting of alcohols having from 1 to 5 carbon atoms, acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof.

6. A process according to Claim 5, including adding crosslinking agents to said solution prior to ejection for reaction with said polymer, and including the step of adding an alkaline compound to said solution so that the pH
of said solution ranges from about 6.5 to about 8.0, said crosslinking agent being an alkaline earth salt, said alka-line earth salt selected from the group consisting of calcium, barium, beryllium and magnesium, said anion portion of said salt selected from the group consisting of carbonate, bi-carbonate, oxide, hydroxide, nitrate, F , Cl , I and Br, the amount of said crosslinking agent ranging from about 0.01 to about 5 percent by weight based upon the total weight of said solution and the amount of said alkaline compound ranging from about 0.01 to about 1 percent by weight based upon the total weight of said solution.

7. A process according to Claim 5, including add-ing an adhesive agent so that upon the in situ formation of an encapsulated particle from said solution and the concurrent and direct application of said encapsulated particle to an inert target, said adhesive agent improves the tackiness of said encapsulated particle to said target

8. A process according to Claim 7, wherein said adhesive agent is an alkyl ester having the formula wherein R1 and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solu-tion.

: 9. A process according to Claim 4, wherein said trace mineral is selected from the group consisting of zinc chloride, zinc sulfate, ferric chloride, ferric sulfate, copper sulfate, copper oxychloride, boric acid, sodium borate, sodium selenate, cobalt sulfate, sodium molybdate, manganese chloride, and combinations thereof; wherein said Nematicide is selected from the group consisting of 0,0-diethyl-0-2,4-di-chlorophenyl phosphorodithioate, 0-ethyl-S,S-dipropyl phos-phorodithioate (Ethoprop), and combinations thereof; wherein said. molluscicide is selected from the group consisting of copper sulfate, n-tritylmorpholine (trifenmorph), tributyltin fluoride, sodium pentachlorphenate, and combinations thereof;
and wherein said fungicide is selected from the group con-sisting of triphenyltin acetate, methyl-l-(butacarbamoyl)-2-benzimidazole carbamate (Benomyl), and combinations thereof.

32

10, A process according to Claim 9, wherein said solvent is selected from the group consisting of alcohols having from 1 to 5 carbon atoms, acetone, diisobutyl ketone acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof.

11. A process according to Claim. 10, including adding crosslinking agents to said solution prior to ejection for reaction with said polymer, and including the step of adding an alkaline compound to said solution so that the pH of said solution ranges from about 6.5 to about 8.0, said crosslinking agent being an alkaline earth salt, said alkaline earth salt selected from the group consisting of calcium, barium, beryllium and magnesium said anion portion of said salt selected from the group consisting of carbonate, bicarbo-nate, oxide, hydroxide, nitrate, F , Cl , I and br, the amount of said crosslinking agent ranging from about 0.01 to about 5 percent by weight based upon the total weight of said solution and the amount of said alkaline compound ranging from about 0Ø1 to about 1 percent by weight based upon the total weight of said solution.

12, A process according to Claim 10, including adding an adhesive agent so that upon the in situ formation of an encapsulated particle from said solution and the con-current and direct application of said encapsulated particle to an inert target, said adhesive agent improves the tacki-ness of said encapsulated particle to said target.

13. A process according to Claim 12, wherein said adhesive agent is an alkyl ester having the formula wherein R1 and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solu-tion.

14. A process according to Claim 13, wherein said solvent is selected from the group consisting of water, alcohols having from 1 to 5 carbon atoms, and combinations thereof.

15. A process according to Claim 4, wherein said particle is a herbicide, said herbicide selected from the group consisting of 2,4-dichlorophenoxyacetic acid (2,4-D), alkyla-mine salts of 2,4-D, butyoxyethanol ester of 2,4-D, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T). 2-(2,4,5-trichloro-phenoxy)propionic acid (Silvex), 3-amino-2,5-dichlorobenzoic acid (chloramben), 3,6-dichloro-0-anisic acid (Dicamba) 2,3,5-trichlorophenylacetic acid (Fenac), 2,6-dichlorobenzo-nitrile (Dichlobenil), N,N-diallyl-2-chloroacetamine (Randox) S-ethyl diisobutylthiocarbamate (Sutan), isopropyl N-(3-chlorophenyl) cabamate (chloropropham), 3-amino-1,2,4-triazole (Amitrole), 2-chloro-4,6-Bis(ethylamino)-isopropyl-amino-S-triazine (Atrazine), and combinations thereof.

16. A process according to Claim 15, wherein said solvent is selected from the group consisting of alcohols having from 1 to 5 carbon atoms, acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof.

17. A process according to Claim 16, including adding crosslinking, agents to said solution prior to ejection for reaction with said polymer, and including the step of adding an alkaline compound to said solution so that the pH
of said solution ranges from about 6.5 to about 8.0, said crosslinking agent being an alkaline earth salt, said alkaline earth salt selected front the group consisting of calcium, barium, beryllium and magnesium, said anion portion of said salt selected from the group consisting of carbonate, bicarbonate, oxide, hydroxide, nitrate, F , Cl , I , Br , the amount of said crosslinking agent ranging from about 0.01 to about 5 percent by weight based upon the total weight of said solution and the amount of said alkaline compound ranging from about 0.01 to about l percent by weight based upon the total weight of said solution

18, A process according to Claim 16, including adding an adhesive agent so that upon the in situ formation of an encapsulated particle from said solution and the con-current and direct application of said encapsulated particle to an inert target, said adhesive agent improves the tacki-ness of said encapsulated particle to said target.

l9. A process according to Claim 18, wherein said adhesive agent is an alkyl ester having the formula wherein R1 and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solution.

20.. A process according to Claim 19, wherein said solvent is selected from the group consisting of water, alcohols having from 1 to 5 carbon atoms, and com-binations thereof.

21. A process according to Claim 4, wherein said particle is a pheromone.

22. A process according to Claim 5, wherein said particle is a pheromone.

23. A process according to Claim 7, wherein said particle is a pheromone.

24. A process according to Claim 8, wherein said particle. is a pheromone.

25. A process according to Claim 4, wherein said particle is an insecticide or an acaricide selected from the group consisting of O,O-diethyl O-p-nitrophenyl phosphorothioate (Parathion), O,O-dimethyl-O-p-nitrophenyl phosphorothioate (Methyl parathion), O,O-dimethyl-0-(3-methyl-4-nitrophenyl)phosphorothioate (Sumithion), O,O-diethyl-O-(2 isopropyl-6 -methyl-5-pyrimidinyl)phosphoro-thioate (Diazinon), O,O-dimethyl-0-[3-methyl-4-(methylthio) phenyl] phosphorothioate (Fention), Pyrethrin-piperonyl butoxide, l-naphthyl methylcarbamate (Carbaryl), 2-(1-methylethoxy)phenyl methylcarbamate (Baygon), 2-methyl-2-(methylthio)propionaldehyde-0-(methylcarbamonyl) oxime (Aldicarb), S-methyl N-[methylcarbamonyl(oxy)] thioacetamine (lannate), chiorinated camphene, 67 percent octachlorocam-phene (Toxaphene), tricalcium aresenate, sodium aluminum fluoride, Dichlorodiphenyltrichloroethane, tricyclohexyltin hydroxide (Plictran), and combinations thereof.

26, A process according to Claim 25, wherein said solvent is selected from the group consisting of alco-hols having from 1 to 5 carbon atoms, acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof.

27. A process according to Claim 26, including adding crosslinking agents to said solution prior to ejec-tion for reaction with said polymer, and including the step of adding an alkaline compound to said solution so that the pH of said solution ranges from about 6.5 to about 8.0, said crosslinking agent being an alkaline earth salt, said alka-line earth salt selected from the group consisting of calcium, barium, beryllium and magnesium, said anion portion of said salt selected from the group consisting of carbonate, bi-carbonate, oxide, hydroxide, nitrate, F , Cl , I and Br , the amount of said crosslinking agent ranging from about 0.01 to about 5 percent by weight based upon the total weight of said solution and the amount of said alkaline compound rang-ing from about 0.01 to about 1 percent by weight based upon the total weight of said solution,

28. A process according to Claim 25, including adding an adhesive agent so that upon the in situ formation of an encapsulated particle from said solution and the con-current and direct application of said encapsulated particle to an inert target, said adhesive agent improves the tacki-ness of said encapsulated particle to said target.

29. A process according to Claim 28, wherein said adhesive agent is an alkyl ester having the formula wherein R1 and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solu-tion.

30. A process according to Claim 29, wherein said solvent is selected from the group consisting of water, alco-hols having from 1 to 5 carbon atoms, and combinations there-of.

31. A process according to Claim 18, 23, or 28, wherein said polymer is said polyvinyl acetate,

32. A process according to Claim 18, 23, or 23, wherein said polymer is said polyvinyl ether.

33. A process according to Claim 18, 23, or 28, wherein said polymer is said polyvinyl ether having two carbon atoms in the repeating group.

34. A process according to Claim 18, 23 or 28, wherein said polymer is said acrylic polymer or copolymer.

35. A process according to Claim 18, 23 or 28, wherein said polymer is said acrylic polymer wherein R4 of said formulation is hydrogen or an alkyl having from 1 to 4 carbon atoms, and wherein said R5 of said formula is hydrogen or an alkyl having from 1 to 3 carbon atoms, and wherein the molecular weight of said polymer or said copoly-mer ranges from about 30,000 to about 300,000.

36. A process according to Clam 18, 23 or 28, wherein said polymer is said interpolymer salt.

37. A process according to Claim 18, 23 or 2&, wherein said polymer is said interpolymer salt, wherein n is 4, x is 10, y is 86, and z is 0. .

38. A process according to Claim 18, 23 or 28, wherein said polymer is said interpolymer salt, wherein n is 8, x is 17, y is 52.5 and z is 22.5.

39. A process according to Claim 18, 23 or 28, wherein said polymer is said interpolymer salt, wherein n is 8, x is 17, y is 75, and z is 0.

40. A process according to Claim 18, 23 or 28 wherein said polymer is polyvinyl acetate and. the amount of said polymer ranges from about 4 percent to about 13 percent by weight, wherein the amount of said solvent ranges from about 50 percent to about 90 percent by weight, and wherein the amount of said particle ranges from about 5 per-cent to about 30 percent by weight.

41. A process according to Claim 18, 23 or 28, wherein said polymer is said polyvinyl ether and the amount of said polymer ranges from about 4 percent to about 13 percent by weight, wherein the amount of said solvent ranges from about 50 percent to about 90 percent by weight, and wherein the amount of said particle ranges from about 5 per-cent to about 30 percent by weight,

42 A process according to Claim 18, 23 or 28, wherein said polymer or copolymer is said acrylic or copolymer, the amount of said polymer ranges from about 4 percent to about 13 percent by weight, wherein the amount of said solvent ranges from about 50 percent to about 90 percent by weight, and wherein the amount of said particle ranges from about 5 percent to about 30 percent by weight.

43. A process according to Claim 18, 23 or 28, wherein said polymer is said interpolymer salt and the amount of said polymer ranges from about 4 percent to about 13 percent by weight, wherein the amount of said solvent ranges from about 50 percent to about 90 percent by weight, and wherein the amount of said particle ranges from about 5 percent to about 30 percent by weight.

44. A process according to Claim 18, 23 or 28, wherein said polymer is said interpolymer salt where n is 4, x is 10 Y is 86, and z is 0, and wherein the amount of said polymer ranges from about 4 percent to about 13 percent by weight, wherein the amount of said solvent ranges from about 50 percent to about 90 percent by weight, and wherein the amount of said particle ranges from about 5 percent to about 30 percent by weight.

45. A process according to Claim 18, 23 or 28, wherein said polymer is said interpolymer salt, wherein n is 8, x is 17, y is 37.5, and z is 37.5.

46. An in situ self-encapsulating polymeric-containing solution for concurrent and direct application to an earth target, characterized in that, based upon the total weight of said solution, said weight ranges from about 003 percent to about 25 percent of a film-forming polymer, from about 35 percent to about 99 per-cent of a solvent, and from about 1 percent to about 40 per-cent of a particle, said particle being soluble or dispersible in said solvent;
said solvent being a compound in which said poly-mer is soluble; and a small amount by weight based upon the total weight of the solution of an adhesive agent so that upon the in situ formation of an encapsulated particle from said solution and the concurrent and direct application of said encapsulated particle to an earth target, said adhesive agent improves the tackiness of said encapsulated particle to said target.

47. A solution according to Claim 46, wherein said polymer is selected from the group consisting of (a) a poly-vinyl acetate, (b) a polyvinyl ether wherein said repeating unit has from 3 to 10 carbon atoms, (c) an acrylic polymer or a copolymer made from monomers having the formula where R4 is hydrogen or an alkyl, cycloalkyl, aryl, or aralkyl having from 1 to 30 carbon atoms and R5 is hydrogen or an alkyl, cycloalkyl, aryl, or aralkyl having from 1 to 12 carbon atoms; (d) the salt of (l) an interpolymer having the structure wherein R and R1 are members of the group con-sisting of hydrogen and methyl; R2 is a member of the group consisting of methyl, ethyl, propyl and butyl; R3 is a member of the group consisting of methyl and ethyl; n represents from 3 to 12 weight percent based on the combined weight of n, x, y and z; x represents from 8 to 25 percent based on -the combined weight of n, x, y and z; y represents from 45 to 89 weight percent based on the combined weight of n, x, y and z; z represents from 0 to 44 weight percent based on the combined weight of n, x, y and z; the sum of the numerical value of n + x + y + z is always exactly 100 and the groups n, x, y and z are present in a heterogeneous relative posi-tion, and (2) a member of the group consisting of ammonia, hydrazine, a low boiling primary aliphatic amine and A low boiling secondary aliphatic amine, said salt being soluble in water in the pH range of from about 5 to 8; and (e) combinations thereof;
wherein the molecular weight of said polyvinyl acetate ranges from about 10,000 to about 100,000, wherein the molecular weight of said polyvinyl ether ranges from about 10,000 to about 100,000, wherein the molecular weight of said acrylic polymer or copolymer ranges from about 10,000 to about 600,000, and wherein the molecular weight of said interpolymer ranges from about 20,000 to about 1,000,000.

48. A solution according to Claim 47, wherein said solvent is selected from the group consisting of alcohols having from 1 to 5 carbon atoms, acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof.

49. A solution according to Claim 48, including crosslinking agents for reaction with said polymer upon ejection and including an alkaline compound so that the pH
of said solution ranges from about 6.5 to about 8.0, said crosslinking agent being an alkaline earth salt, said alkaline earth salt selected from the group consisting of calcium, barium, beryllium and magnesium, said anion portion of said salt selected from the group consisting of carbonate, bicarbonate, oxide, hydroxide, nitrate, F , Cl , I , Br , the amount of said crosslinking agent ranging from about 0.01 to about 5 percent by weight based upon the total weight of said solution and the amount of said alkaline compound rang-ing from about 0.01 to about 1 percent by weight based upon the total weight of said solution.

50. A solution according to Claim 48, wherein said adhesive agent has the formula wherein R1 and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solution.

51. A solution according to Claim 47, wherein said particle is selected from the group consisting of an insecticide, a trace mineral, an acaricide, a nematicide, a molluscicide, a herbicide, a fungicide, a pheromone, an odorant, a fragrance, an attractant, a repellant, and combina-tions thereof.

52. A solution according to Claim 51 wherein said solvent is selected from the group consisting of alcohols having from 1 to 5 carbon atoms, acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof. :
:

53. A solution according to Claim 52, wherein the amount of said polymer ranges from about 4 percent to about 13 percent by weight, wherein the amount of said solvent ranges from about 50 percent to about 90 percent by weight, and wherein the amount of said particle ranges from about 5 percent to about 30 percent by weight.

54. A solution according to Claim 53, wherein said adhesive agent has the formula wherein Rl and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solution.

55. A solution according to Claim 54, wherein said solvent is selected from the group consisting of water, an alcohol having from 1 to 5 carbon atoms J and combinations thereof.

56. A solution according to Claim 51, wherein said trace mineral is selected from the group consisting of zinc chloride, zinc sulfate, ferric chloride, ferric sulfate, copper sulfate, copper oxychloride, boric acid, sodium borate, sodium selenate, cobalt sulfate, sodium molybdate, manganese chloride, and combinations thereof; wherein said insecticide and said acaricide is selected from the group consisting of O,O-diethyl-0-p-nitrophenyl phosphorothioate (Parathion), O,O-dimethyl-0-p-nitrophenyl phosnhorothioate (Methyl para-thion), O,O-dimethyl-0-(3-methyl-4-nitrophenyl)phosphoro-thioate (Sumithion), O,O-diethyl-0-(2-isopropyl-6-methyl-5-pyrimidinyl)- phosphorothioate (Diazinon), O,O-dimethyl-0 [3-methy1-4-methylthio)phenyl] phosphorothioate (Fenthion), Pyrethrin-piperonyl butoxide, l-naphthyl methylca.rbamate (Carbaryl), 2-(1-methylethoxy)pheyl methylcarbamate (Baygon), 2-methyl-2-(methylthio)propionaldehyde-a-(methyl carhamonyl) oxime (Aldicarb), S-methyl-N-[methylcarbamonyl(oxy)] thio-acetamine (lannate), chlorinated camphene, 67 percent octa-chlorocamphene (Toxaphene), tricalcium aresenate, sodium aluminum fluoride, Dichlorodiphenyltrichloroethane, tricyclo-hexyltin hydroxide (Plictran), and combinations thereof;
wherein said Nematicide is selected from the group consisting of O,O-diethyl-0-2,4-dichlorophenyl phosphorothioate (dichlo-fenthion), O-ethyl S,S-dipropyl phosphorodithioate (Ethoprop), and combinations thereof; wherein said molluscicide is selected from the group consisting of copper sulfate, n-tri-tylmorpholine (trifenmorph), tributyltin fluoride, sodium pentachlorophenate, and combinations thereof; wherein said herbicide is selected from the group consisting of 2,4-dichlorophenoxyacetic acid (2,4-D), alkylamine salts of 2,4-D, butoxyethanol ester of 2,4-D, 2,4,5-trichlorophenoxy-acetlc acid (2,4,5-T), 2-(2,4,5-trichnlorophenoxy)priopionic acid (Silvex), 3-amino-2,5-dichlorobenzoic acid (chloramben), 3,6-dichloro-0-anisic acid (Dicamba, 2,3,5-trichlorophenyl-acetic acid (Fenac), 2,6-dichlorobenzonitrile (Dichlobenil), N,N-diallyl-2-chloroacetamine (Randox), S-ethyl diisobutyl-thiocarbamate (Sutan), isopropyl N-(3-chlorophenyl) carbamate (chloropropham), 3-amino-1,2,4-triazole (Amitrole), 2-chloro-4,6-Bis(ethlamino)-isopropylamino-S-triazine. (Atra-zine), and combinations thereof; and, wherein said fungicide is selected from the class consisting of triphenyltin acetate methyl-l-(butacarbamoyl)-2-benzimidazole carbamate (Benomyl), and combnations thereof.

57. A solution according to Claim 56, wherein said solvent is selected from the group consisting of alco-hols having from 1 to 5 carbon atoms, acetone, diisobutyl ketone, methyl ethyl ketone, dioxane, methylene chloride, water, and combinations thereof.

58. A solution according to Claim 57, wherein the amount of said polymer ranges from about 4 percent to about 13 percent by weight, wherein the amount of said solvent ranges from about 50 percent to about 90 percent by weight, and wherein the amount of said particle ranges from about 5 percent to about 30 percent by weight.

59. A solution according to Claim 58, wherein said adhesive agent has the formula wherein Rl and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solution.

60. A solution according to Claim 59, wherein said solvent is selected from the group consisting of water, an alcohol having from 1 to 5 carbon atoms, and combinations thereof.

61. A solution according to Claims 47, 51 or 58 wherein said polymer is said polyvinyl acetate.

62. A solution according to Claim 47, 51 or 58, wherein said polymer is said polyvinyl ether.

63, A solution according to Claim 47, 51 or 58, wherein said polymer is a polyvinyl ether having two carbon atoms in the repeating group.

64. A solution according to Claim 47, 51 or 58, wherein said polymer is said acrylic polymer or copolymer.

65. A solution according to Claim 47, 51 or 58, wherein said polymer is said acrylic polymer or copolymer, and wherein R4 of said formulation is hydrogen or an alkyl having from 1 to 4 carbon atoms, and wherein R5 of said formula is hydrogen or an alkyl having from 1 to 3 carbon atoms, and wherein the molecular weight of said polymer or said copoly-mer ranges from about 30,000 to about 300,000.

66. A solution according to Claim 47, 51 or 58, wherein said polymer is said interpolymer.

67. An encapsulated particle having been in situ encapsulated and concurrently and directly adhered to an earth target, being characterized by a particle, said particle encapsulated with a film-forming polymer, said particle having been in situ encapsulated and concurrently and directly applied to the earth target, said encapsulated particle containing a small amount of an adhesive agent so that said encapsulated parti-cle has improved tackiness and adheres to said earth target.

68. An encapsulated particle according to Claim 67, wherein said polymer is selected from the group consisting of (a) a polyvinyl acetate; (b) a polyvinyl ether wherein said repeating unit has from 2 to 10 carbon atoms; (c) an acrylic polymer or a copolymer made from monomers having the formula where R4 is hydrogen or an alkyl, cycloalkyl, aryl, or aralkyl having from 1 to 30 carbon atoms and R5 is hydrogen or an alkyl, cycloalkyl, aryl, or aralkyl having from 1 to 12 carbon atoms; (d) the salt of (1) an interpolymer having the structure wherein R and R1 are members of the group consist-ing of hydrogen and methyl; R2 is a member of the group consisting of methyl, ethyl, propyl and butyl; R3 is a member of the group consisting of methyl and ethyl; n represents from 3 to 12 weight percent based on the combined weight of n, x, y and z; x represents from 8 to 25 percent based on the combined weight of n, x, y and z; y represents from 45 to 89 weight percent based on the combined weight of n, x, y and z, z represents from 0 to 44 weight percent based on the combined weight of n, x, y and z; the sum of the numerical value of n + x + y + z and always exactly 100 and the groups n, x, y and z are present in a heterogeneous relative posi-tion, and (2) a member of the group consisting of ammonia, hydrazine, a low boiling primary aliphatic amine and a low boiling secondary aliphatic amine, said salt being soluble in water in the pH range of from about 5 to 8; and (e) com-binations thereof, wherein the molecular weight of said polyvinyl acetate ranges from about 101000 to about 100,000, wherein the molecular weight of said polyvinyl ether ranges from about 10,000 to about 100,000, wherein the molecular weight of said acrylic polymers ranges from about 10 9 000 to about 600,000, and wherein the molecular weight of said interpoly-mer ranges from about 20,000 to about l,000,000.

69. An encapsulated particle according to Claim 68, including adding crosslinking agents for reaction with said polymer upon ejection, and including an alkaline compound so that the pH of said solution ranges from about 6.5 to about 8.0, said crosslinking agent being an alkaline earth salt, said alkaline earth salt selected from the group con-sisting of calcium, barium, beryllium and magnesium, said anion portion of said salt selected from the group consisting of carbonate, bicarbonate, oxide, hydroxide, nitrate, F , Cl , I and Br , the amount of said crosslinking, agent ranging from about 0.01 to about 5 Percent by weight based upon the total weight of said solution and the amount of said alkaline compound ranging from about 0.01 to about 1 percent by weight based upon the total weight of said solu-tion.

70. An encapsulated particle according to Claim 68, wherein said adhesive agent has the formula wherein R1 and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said en-capsulated particle.

71. An encapsulated particle according to Claim 68, wherein said particle is selected from the group con-sisting of insecticides, fungicides, herbicides, nutrients, trace minerals, nematicides, molluscicides, acaricides, pheromones, odorants, attractants, fragrances, and repellants.

72. An encapsulated particle according to Claim 71, wherein said trace mineral is selected from the group consisting of zinc chloride, zinc sulfate, ferric chloride, ferric sulfate, copper sulfate, copper oxychloride, boric acid, sodium borate, sodium selenate, cobalt sulfate, sodium molybdate, manganese chloride, and combinations thereof;
wherein sand insecticides and said acaricides are selected from the group consisting of pyrethrin-piperonyl butoxide, O,O-dimethyl-O-p-nitrophenyl phosphorothioate, O,O-dimethyl-O-(3-methyl-4-nitrophenyl)phosphorothioate, O,O-diethyl-O-(2-isopropyl-6-methyl-5-pyrimidinyl) phosphoro-thioate, O,O-dimethyl-O-[3-methyl-4-(methylthio)phenyl]
phosphorothioate, l-naphtyl methylcarbamate, 2-(1-methyl-ethoxy)phenol methylcarbamate, 2-methyl-2-(methylthio) propionaldehyde-O-(methyl carbamonyl)oxime, 5-methyl-N-[methyl carbamoyl(oxy)] thioacetamide, chlorinated camphene, 67 percent octachlorocanphene, tricalcium aresenate, sodium aluminum fluoride, dichlorodiphenyltrichloroethane, tricyclo-hexyltin hydroxide, and combinations thereof;
wherein said nematicides include O,O-diethyl-O-2,4-dichlorophenyl phosphorothioate, O-ethyl S,S-dipropyl phosphorodithioate, and combinations thereof;
wherein said molluscicides include copper sulfate, trihutyltin fluoride, n-tritylmorpholine, sodium penta-chlorophenate, and combinations thereof;
wherein said herbicides include 2,4-dichlorophenoxy-acetic acid, alkylamine salts of 2,4-D, butoxyethanol ester of 2,4-D, 2,4,5-trichlorophenoxyacetic acid, 2-(2,4-,5-tri-chlorophenoxy)propionic acid, 3-amino-2,5-dichlorobenzoic acid, 3,6-dichloro-0-anisic acidl 2,3,6-trichlorophenyl-acetic acid, 2,6-dichlorobenzonitrile, N,N-diallyl-2-chloro-acetamide, isopropyl N-(3-chlorophenyl)carbamate, S-ethyl diisobutylthiocarbamate, 3-amino-1,2,4-triazole 2-chloro-4,6-Bis(ethylamino)-S-triazine, 2-chloro-4-ethylamino-6-isopropylamino-S-triazine, and combinations thereof; and wherein said fungicides include triphenyltin acetate, methyl-l-(butacarbamoyl)-2-benzimidazole carbamate, and combinations thereof.

73. An encapsulated particle according to Claim 71, wherein the amount of said polymer ranges from about 0.3 percent to about 25 parts by weight, and wherein the amount of said particle ranges from about 1 part to about 40 parts by weight.

74. An encapsulated particle according to Claim 73, including an adhesive agent, said adhesive agent being an alkyl ester of the formula wherein R1 and R2 have from 2 to 5 carbon atoms, and the amount of said adhesive agent ranges from about 0.01 to about 3 percent by weight based upon the total weight of said solution .

75. An encapsulated particle according to Claim 68, 71, or 73, wherein said polymer is said polyvinyl acetate.

76. An encapsulated particle according to Claim 68, 71, or 73, wherein said polymer is said polyvinyl ether.

77. An encapsulated particle according to Claim 68, 71, or 73, wherein said polymer is a polyvinyl ether having two carbon atoms in the repeating unit.

78. An encapsulated particle according to Claim 68, 71, or 73, wherein said polymer is said acrylic polymer or copolymer.

79. An encapsulated particle according to Claim 68, 71, or 73, wherein said polymer is an acrylic polymer or copolymer, and wherein R4 of said formulation is hydrogen or an alkyl having from 1 to 4 carbon atoms, and wherein said R5 of said formula is hydrogen or an alkyl having from 1 to 3 carbon atoms, and wherein the molecular weight of said polymer or said copolymer ranges from about 30,000 to about 300,000.

80. An encapsulated particle according to Claim 68, 71, or 73, wherein said polymer is said interpolymer.