CA1064785A - Internally coated reaction vessel and process for coating the same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A reaction vessel having on the internal surfaces thereof a coating containing, as a primary ingredient, a straight chain or branched polyaromatic amine made by the re-action of any one by itself, except the polyhydric phenols, or more than one, of the compounds selected from polyamino benzenes, polyhydric phenols, aminophenols, alkyl-substituted aminophenols, diphenylamines, and alkyl-substituted diphenyl-amines, which coating is applied to said surfaces from an organic solvent solution. Also included are the above compounds having a halogen substitution on the ring. Further, there is included the process for coating said internal surfaces whereby polymer build-up on said surfaces is substantially sliminated.

Description

~64785 The invention relates to a polymerization reaction vessel and its method of manufacture and to a process for the polymerization of olefinic monomers in a polymerization reaction vessel.
Various type chemical processes are commonly carried out in large, stirred vessels which are frequently provided with auxiliary equipment, such as baffles, heat transfer coils which enable heat to be supplied or extracted from the contents of the ; vessels, and the like. In many cases, however, such processes eventually produce undesirable deposits on the surfaces of the equipment with which the reaction mixtures come into contact.
Such deposits interfere with the efficient transfer of heat to and from the interior o~ the vessels. Further, theQe deposits have a tendency to deteriorate and to partially fragment result-ing in contamination of the reaction mixture and the products produced therefrom. This problem is particularly prevalent in polymerization type reactions, since the deposit, or "build-up", of`solid polymer on reactor surface~, not only interferes with heat transfer, but decreases productivity and adversely affects ; 20 polymer quality.
This problem is particularly bad in the commercial pro-duction of polymèrs and copolymers of vinyl and vinylidene , halides, when polymerized alone or with other vinylidene monomers having a terminal CH2aC~ group, or with polymerizable polyole-finic monomers. For example, in the commercial production of vinyl chloride polymers, the same are usually produced in the form of discrete particles by polymerization in aqueous suspension systems. When employing such a polymerization system, the vinyl chloride, and other comonomers when used, are maintained in the form of small discrete droplets by the use of suspending agents and agitation. When the reaction is complete, the resultant polymer is washed and dried. These aqueous suspension system '~

-64~85 polymerization reactions are usually conducted under pressure in m~tal reactors equipped with baffles and high speed agitators.
However, these suspension systems are inherently unstable and during the polymerization reaction, vinyl chloride polymer builds up on the interior surfaces of the polymerization reactor, in-cluding the surfaces of the baffles and agitator. Obviously, this polymer build-up must be removed since it results in further formation of polymer build-up on the reactor surfaces which results in a crust that adversely affects heat transfer and contaminates the polymer being produced.
The nature of the polymer build-up or insoluble deposit on the walls of the reactor is such that in the com-mercial production of polymers, as described above, it has in the past been stand æ d practice, after each polymerization re-action is completed, to have an operator enter the reactor and ; scrape the polymer build-up off the walls and off the baffles and agitator. An operation such as this is not only costly, both in labor and down-time of the reactor, but presents potential health hazards as well. While various methods have heretofore been proposed to reduce the amount and nature of polymer build-up on polymerization reactor surfaces, such a solvent cleaning, various hydraulic and mechanical reactor cleaners, and the like, none has proved to be the ultimate in polymer build-up removaI. That is to say, these various methods and apparatus have done an acceptable job, but there is still room for improvement in this area, particularly from an economic point of view.
Further, it has recently been determined that vinyl chloride in the atmosphere is injurious to the health of humans .
and, as a result, the U.S.A. Government has issued certain regulations that require PVC (polyvinyl chloride) producers to maintain a very low concentration of vinyl chloride in the i4785 atmosphere of their plants. It is heretofore desirable to be able to operate a PVC plant without having to open the reaction vessels or polymerizers after each charge or batch is polymer-ized for the purpose of cleaning the reactor. Being able to operate a closed polymerization system would prevent the escape into the atmosphere of residual vinyl chloride present in the reactor after each batch is made. Also, elimination of polymer build-up also eliminates the presence of residual vinyl chloride in said build-up. Accordingly, a process ox means of producing PVC, and like polymers, which not only eliminates polymer build-up, but also reduces and/or eliminates pollution of the atmos-phere would be most desirable, and indeed essential.
It has been found that if a reaction vessel has been previously coated on the interior surfaces with the proper coat-ing undesirable polymer build-up on said surfaces can be sub-stantially decreased, and in some cases, entirely eliminated.
We have unexpectedly found that when the interior surfaces of a reactor or polymerizing vessel, whether metal or glass-lined, are covered with a film or coating containing, as a primary ingredient, a straight chain or branched polyaromatic amine made by the reaction of any one by itsel~, except the polyhydric phenols, or with any one or more, of the compounds selected from polyamino benzenes, polyhydric phenols, aminophenols, alkyl-sub-stituted aminophenols, diphenylamines, and alkyl-substituted diphenylamines, including halogen substitution on any of said compounds, polymer build-up on said surfaces is essentially eliminated and multiple charges or batches of polymer can be made in said reaction vessel without opening the same. The poly-aromatic film or coating i9 very easily applied to the interior surfaces of the reaction vessel from an organic solvent solution thereof.

.

647~S
In one aspect the invention relates to a polymerization reaction vessel having on the internal surfaces thereof a coat-ing comprised of a polyaromatic amine as hereinafter defined, the polyaromatic amine being straight chained or branched and having a molecular weight greater than about 250.
In another aspect the invention provides a method of preparing a polymerization vessel 90 as to substantially eliminate the build-up of polymers on the internal surfaces of the vessel, which comprises applying to the surfaces a coating comprised of the polyaromatic amine, as hereinafter defined in an organic solvent therefor.
In another aspect there is provided an improvement in a process for the polymerization of olefinic monomers, which comprises polymerizing a monomer or monomers in an aqueous polymerization medium and keeping the medium in constant contact throughout the polymerization reaction with a surface having thereon a water'insoluble coating comprised of a poly-aromatic amine as hereinafter descri,bed.
In accordance with the present invention, a film or coating of a polyaromatic amine is applied to the interior .,. ~ , - 4 -.... .

71~

surfaces o* the reactor by means of an organic solvent solution thereof, in which reactor polymerization reactions are carried out. Likewise, all exposed surfaces on the interior of the reactor, such as the baffles, agitator 9 and the like~ are also coated in like manner. The coating thus applied is readily insolubilized by the use of heat to evaporate the organic sol-vent thereby leaving on said surfaces a tightly adhering, var~
nish-like coating that will last through multiple polymeriza-tion cycles before it needs to be reapplied. The exact mech-anism by which the polyaromatic amine coating functions to prevent build-up of polymeric scale on the inner sur~aces of the reaction vessel is not certain but it is believed to be a free radical destroying mechanism or free radical trapping mechanism. This is so because aromatic diamines are known to ~5 destroy free radicals, ~or example, as in their well-kno~n activity as antioxidants. Thus, with the destruction of the free radicals by the polyaromatic amine coating, polymerization on the coated sur~aces is inhibitedl The straight chain or branched polyaromatic amines, use~ul in the coatings of ~he instant inven~ion, are made by reacting any one of the compounds listed below with itself, with the exception of the polyhydric phenols, by means of a con-densation reaction or reacting or condenslng two or more of said compounds together. Generally, such reactions are carried out with heat in the presence of an acidic catalyst. The polyaro-matic amines thus formed have the following general structures:

(A) Rl ~ A-N ~ C ~ -B ~ R2 wherein A, B and C~are either ~4L785 R5 ~ or ~ , wherein R3 and R4 are the same as defined below, and R5 is H
-N-, or a straight chain or branched alkylene or alkylidene group containing f'rom 1 to 5 carbon atoms, and wherein A, B, and C may be the same or di~ferent and each repeating unit may be the same or di~ferent; Rl and R2 are either -H, -OH, -NH2 or , ,/~ ' ~ ;

R3 and R4 are either -H, halogen, -OH, -NH2, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or di~erent; x is an integer from 1 to 20; and y is an integer from O to 20. When a tri~unctional compound is ; emplo~ed, such as the trihydroxy benzenes, f`or example, then ~: branched chains will result thus producing a branched poly-aromatic amine.
. H H
(B) Rl - ~ A-N ~ B-N- y R2 wherein A and B are either R5 ~ ~ or wherein R3, R4 and R5 are the same as in ~ormula (A), and : 20 wherein A and B may be the same or dif`f'erent and each repeat-ing unit may be the same or dif'ferent; Rl is -H, ~OH, -NH2 or ~647E~5 ~i R3 R~
R2 is -H, -OX, or ~;' ; R3 R4 x is an integer from l to 4; and y is an integer ~rom l to 15.
The compounds generally useful in making the poly-aromatic amines employed in the present invention are (a) the : polyamino benzenes having the ~ormula:
NH

~ NH2 Rl R2 wherein Rl and X2 are either -H, halogen, -NH2, ~OH or an alkyl group containing ~rom 1 to 8 carbon atoms, and may be the same or di~erent, such as, for example, ortho, meta and paraphenylene diamines; diamino toluenes, diamino xylenes, diamino phenols, triamino benzenes, toluenes and xylenes, ethyl, propyl, butyl and pentyl di- and tri-amino benzenes;
and the like; the most pre~erred compounds being those in which Rl is -H and R2 is ~H, methyl, or ethyl; (b) the poly-hydric phenols having the ~ormula OH
~0~

wherein R3 and R4 are either -H, halogen, -NH2, -OH, or an alkyl group containing from l to 8 carbon atoms, and may be the same or different, such as, for example, catechol, resor-'785 cinol, chloro-resorcinol, hydroquinone, phloroglucinol, pyrogallol, etc.j dih~droxy toluenes and xylenes; trihydroxy toluenes and xylenes 3 ethyl, propyl, butyl and pentyl di- and trihydroxy benzenes; and the like, the most preferred compounds being those in which R3 is -H and R4 is -H or -OH; (c) the aminophenols and alkyl-substituted aminophenols having the formula OH

~2 wherein R5 and R6 are either -H, halogen, -NH2, -OH or an alkyl group containing from 1 to 8 carbon atoms, and may be the same or different, such as, for example, ortho, meta, and para-aminophenolsj diamino- and triamino- phenols; methyl;
eth~1, propyl, butyl and pentyl amino and diaminophenols; and the like, the most preferred compo~rnds being those in which R5 is -H and R6 is -H or -NH2; and (d) diphenylamines, alkyl-sub-stituted diphenylamines and other compounds having the formula ~ R ~

H
wherein R is -N- or a straight chain or branched alkyl group containing from 1 to 5 carbon atoms, and Rl, R2, R3 and R4 may each be -H, -NH23 -OH, halogen or an alkyl group containing from 1 to ~ carbon atoms and at least two are -NH2, -OH or one of each, such as, for example, bis-phenol A, and the like, 10~i4';~85 the most pre~erred compounds being those in which Rl and R~
are -OH or - ~ and R2 and R3 are ~H.
The halogen in the above ~ormulas may be chlorine, bromine, iodine, or fluorine. The presence of the halogen atoms does not a~ect the solubility of the polyaromatic amines in organic solvents.
When reacting two or more o~ the above compounds to-gether, by means of a condensation reaction, at least one o~
; the compounds must contain an amino group and in the case o~
more than two compounds involved in the reaction, it is pre-~erable that at least two of said compounds contain an amino group. For example, useful polyaromatic amines are those formed by condensing together m-phenylenediamine, resorcinol and p-aminophenol, as well as by condensing together m-phenyl-; 15 enediamine, resorcinol, phloroglucinol and m-aminophenol, etc.
The molecular weight, or degree o~ condensation, o~
the polyaromatic amine depends upon the ratio in which the reactants, i~ more than one compound is employed, are combined, the time and temperature o~ heating, and the kind and concen-tration o~ the catalyst. When self-condensing any of the abo~e-named compounds, the time and temperature of heating, and the kind and concentration o~ the catalyst will likewise be im-portant in regulating the ~inal molecular weight. Further, the molecular weight can be regulated by uslng small amounts ~ mono-~unctional compounds. For example, Gne can use small amounts of an aromatic monoamine or a phenol to ~ap the poly-merization and thereby control the molecular weight. Poly-aromatic amines having a molecular weight greater than about 250 are satis~actory for use in the present i~vention. The upper limit o~ molecular weight will vary depending upon the ~69L7~
particular compound or compounds used in making the polyaromatic amine. Suf~ice it to say that the part~cular compound m~st have a molecular weight such that it is workable and soluble in an organic solvent so that it can be easily applied to the inner sur~aces o~ the reactor. We have found that polyaromatic amines having a molecular weight in the range o~ about 250 to about 2000 are preferred.
While all of the previously described polyaromatic amines are useful in the practice of the present invention, particularly useful polyaromatic amines are those obtained when a~ aromatic diamine and a polyhydric phenol are reacted together. Usually these compounds are reacted together in ap-proximately equal molar ratio. However, one can use an excess o~ either the dlamire or the phenol. The only difference is that when an excess o~ the polyhydr:Lc phenol is employed, poly-; aromatic amines are obtained which have a somewhat higher soft-en-Lng point than those made in the presence of an excess o~
the aromatic diamine. While some of the polyaromatic amines u~e~ul in the present invention do not have a definlte soften-ing ~oint, it has been ~ound that ~mong the solid polyaromatic amines those having a so~tening point in the range oi about 65C. to about 175C~ are most satisiactory.
The so~tening point o~ the polyaromatic am~ne9 as used herein, i~ determine~ as follows: the polyaromatic amine is melted and ca~t into a split aluminum mold to make a cube which is 1/2 inch on a side. The mold is cooled, the cube re-mo~ed there~rom and allowed to cool thoroughly. The cube is then attached to a the~mometer bulb by heatlng the bulb to a temperature in excess o~ the expected so~tenlng point and la~-i~g it on the side o~ the cube, then coollng to 35C. The thermometer with the cube attached ls inserted into a mercury bath which has been preheated to 35C. The insertion is made 1~47~35 so that the top face or side of the cube is one inch below the mercury surface. The mercury bath is then heated at a rate of 4C. per minute. The softening point is determined as the temperature at which, as the cube moves upward, the cube just breaks the surface of the mercury. It is to be noted that the cube should crawl up on the thermometer and not "pop-up". This is accomplished by carefully controlling the rate of rise in temperature of the mercury bath.
Again it is reiterated that many polyaromatic amines useful in the practice of the present invention do not have definite softening points but are viscous, flowable materials which are normally solid at room temperature. However, when these polyaromatic amines are dissolved in an organic solvent and de-po~ited on the reactor surfaces, they leave a monomer- and water-insoluble film or coating thereon upon removal of the solvent therefrom, thu~ accomplishing the o~jectives of the invention.
It has heretofore been pointed out that when any of the above-identified compounds are self-condensed except the poly-hydric phenols, or reacted with one or more other compounds, an acid catalyst is employed. We have found HCl to be the mos~
effective catalystO However, other useful catalysts may likewise ~- be e~ployed, such as, for ~xample, methane sul~onic acid, ~enzene sulfonic acid, sulfanilic acid, phosphoric acid, iodine, benzene disulfonic acid, hydrogen bromide (B r), hydrogen iodide (HI~, aluminum chloride, and the like. The concentration of catalyst will vary depending upon the particul~r one used. It has been found, however, that a catalyst concentration of from about O.005 mole to about 0.20 mole per mole of the compound being self-condensed, or per mole of the amino compound when one or more compounds are being reacted, is satisfactory. At any rate, the amount of catalyst employed is not critical.

~L~69L785 The temperature of the reaction o~ the compounds, either alone or with others~ will vary depending upon the time o~ the reaction and the molecular weight desired in the final product. For example, one can heat the reaction ingredients to 315C. rapidly and then hold at that temperature for various ; periods of time. Also 9 the reaction ingredients can be heat~d to various temperatures above 300C. and immediately cooled~
When thiæ l~t~er procedure is employed, we de~ine the tim~ o~
reaction as 0 hours. Accordingly, the t~mperature o~ the reaction will vary ~rom about 250C. to a~out 360C. and the time of reaction w~ll vary from abou~ 0 hour to about 3 hours.
The preferred range of reaction te~peratur~ is from 275C. to 330C. and the time o~ reaction from 0 hour to 1 hour. It is understood~ o~ course, that the particular time and temperature l~ selected is dependent upon the catalyst employed and the ~inal molecular weight of the polyaromatic amine desired, The polyaromatic amine coating solution is made by conventional methods, using heat and agitatlon where necessary.
The polyaromatic amine is dissolved in an appropriate organic s~lvent, or in a combination solv~nt, such as, ~or example, two or more organic solvents or an organic solYent mixed with an inorganic material, such as water, to gi~e a solution that has a viscosity such that ~t can be sprayed or brushed on the reactor sur~aces, such as in the case of palnt or rarnish.
Usually a coating solutlon hav~ng a solids content ln the range o~ about 0.10% to about 10.0% by weight is satisfactory. How-ever, the solids content depends upon the molecular weight of the polyaromatic amine. That is, the solids content could, in certain instances9 be greater than 10.0% or less than 0.10~
by weight. In additlon, additives may be emplo~ed in the coat-lng, if desired, such as plasticizers, dyes, stab~lizers, lubricants9 fillers, or pigme~ts, and the llke. 0~ course~

-~6~S

when additives are employed, suitable ad~ustment in the solids content o~ the coating solution ls made. Many known organic solvents may be employed in making the coatings o~ the instant invention depending upon the polyaromatic amine used. As ex-amples of such solventsa there may be named methyl alcohol, ethyl alcohol, Cellosolve (monoethyl ether o~ ethylene ~Lycol), tetrahydrofuran containing 10% waterJ dimethylformamide, di-methylsul~oxide, met~yl amine, ethyl amlne, butylamine, dibutyl-amine, cyclohexylamine, diethylenetriamine, acetone, ethylene glycol, and the like.
After application of the coating to the surfaces to be protected, the coating, or the polyaromatic amine is dried or cured by vaporizing the solvent. With very volatile sol-vente, su~h as methanol, it is mere:Ly su~icient to blow air through the reaction veæsel to remove the solvent or vapors.
With higher boiling solvents, such ~s dimethyl~ormamide, it may - be necessary to heat the reaction ~essel wall while blowing air through the vessel, or evacuating the vessel, in order to remove the solvent ~rom the coating Also, heating o~ the coaking ean be accomplished by the use o~ heaters positione~
internall~ o~ the reactor, or by radiant heating.
S~nce the coating, or polyaromatic ~mine,mu~t be in-soluble in the reaction mixture, it must be insoluble in both water and vinyl chloride, and/or other monomer or monomeræ
present in the reaction mixture. The polyaromatic amines o~
the present invention are insoluble in water and have a very low order, i~ not nil, of solubility in vi~yl chloride, and other monomers use~ul i~ ~orming polymers and copolymers, the solubility decreasing as the molecular wei~ht, or so~tening point, increases. It ls also necessary that the coating should remain substantially chemically and physically unaf~ected in the presence of the components of the reaction, that iS9 it * trademark - \
i4'7~5 should be substantially lnert under the reaction conditions.
As previously pointea out, the coat~ng may be applied to the interior surfaces of the ~eaction vessel in any conven-ient manner, such as b~ spraying, brushing on, dipping, ~lood-ing, and the like. Brushing has been found to be efflcient since it insures complete coverage of all surfaces. Any un-covered areas, such as pinholes, etc., should be avoided inas-much as such exposed areas provide sites ~or pol~mer build-up.
If desired, more than one application or layer of the coating may be used. In many instances, depending upon the condition of the surface being coated~ plural layers are desirable since complete coYerage is thereby insured. In this regard, it should be noted that for best results the sur~ace being coated should be as clean and smooth as possible. In the case of metal surfaces, cleaning by acid etching or abrading is satis-factory.
The amount of coating applied, or the thickeness thereof, is not particularly critical. However, for economic reasons, as thln a coating as possible should be applied to the sur~aces to be protected but still insuring complete cover-age. Again, it should be borne in mind that in addition to coating the interior surfaces or walls of the reaction vessel, all other p~rts therein should likewise be coated, such as baffles, agitator shaft and bladesg heating coils, temperature probes, and the like. Suf~ice it to say that a sufficient amount of coating should be employed to obtain a contlnuous ~ilm over all interior surYaces o~ the reaction vessel with no areas of said surfaces remaining unprotected.
After application and curing or drying of the coating on the interior surfaces o~ the reaction vessel, the reactlon to be carried out in the equipment may be commenced immediately, no particular modification of processing techni~ues being re-1~6~7~5 quired due to the presence o~ the coating. Further~ utiliza-tion of the lnternally coated reaction vessel of the present invention does not adversely a~ect the heat stability or other physical and chemical properties of the polymers produced therein. Ordinary care should, o~ course, be exercised to avoid rough, physical contact with th~ coated surfaces because of the damage to the ~ilm which may result ~rom such contacts.
While the present invention is specifically illus-trated hereina~ter with regard to the suspens:Lon polymerization o~ vinyl chloride, it is to be understood that the apparatus and process may likewise be applled in the dispersion, emulsion, or suspension polymerization of any polymerizable ethylenically unsaturated monomer or monomers where undesirable polymer build-up occurs. Examples of such monomers are other vinyl halides and vinylidene halides 9 such as vinyl bromide, vinyli-dene chloride, etc~; vinylidene monomers having at least one terminal CH2=C' grouping, such as lesters of acrylic acid, ~or example, methyl acrylate, ethyl acr;~late, butyl acrylate 3 octyl acrylate, cyanoethyl acrylate, and the like~ vinyl acetate, esters o~ methacrylic acid such as methyl methacrylate, butyl methacrylate, and the lik~; styrene and styrene derivatives ; i~cluding ~-methyl styrene, vinyl toluene, chlorostyrene; vinyl naphthalene; diolefins including butadiene, isoprene, ~hloro-prene, and the like; and mixtures of any of these typPæ o~
monomers and other vinylidene monomers copolymerizable there-with; and oth~r vinylidene monomers of the types known to those skilled in the art.
The present invention, however, is particularly appli-cable to the æuspension polymerization o~ vinyl chloride, either alone or in admixture with one or more other vinylidene monomers havlng at least one terminal C~ =C~ grouping, copoly-merlzable therewith in amounts as great as about 80% or more by ~ ~6~5 weight, based on the weight of the monomer mixture5 since poly-mer build-up in the reaction vessel is a particularly bad pro-blem here.
In the present invention, the polymerizatlon process is usually conducted at a temperature In the range of about 0C. to about 100C. depending upon the particular monomer or monomers belng polymerized. However~ it is pre~erred to employ temperatures in the range of about 40C. to about 70C., since, at these temperatures polymers having the most beneficial pro-perties axe produced. The time o~ the polymerization reaction will normally vary from about 2 to about 15 hours.
The polymerization process may be carried out at autogenous pressures although superatmospheric pressures of up to 10 atmospheres or more may be employed with some advantage with the more volatile monomers. Superatmospheric pressures may also be ~mployed with those monomers having the requisite volatilities at reaction temperaturles permitting reflux cool-ing of the reaction mixture.
In order to more clearly define the present invention, the ~ollowin~ specific examples are given. It is to be under-stood, however, that this is merely intended in an illustrative and not in a limitative sense. In the examples~ all parts and percents are by welght unlesg otherwise indicated.
- EXAMPLE I
~ - ..... .
In this Example m-phenylenediamine ~m-PDA) was re-acted with resorcinol (R) in a molar ratio of m-PDA/R o~ 1.2 in a glass reactlon veseel in the presence of 0.10 mol o~ HCl per mole of m-PDA as catalyst. The temperature of the react~on mixture was raised to 305~C. and then immediately cooled. Thls a~ounted to 0.0 hour at maximum temperature. The resultant polyaromatic amine had a softenlng point o~ 92C. The pol~-aromatic amine was then dissolved in Cellosolve to give a 0,5%

~C~64~3S
by weight coating solution. The inner surfaces of a polymeriza-tion rea~tor were coated by brushing the solution thereon with an absorbent pad and drying by means of heat.
To the internally coated reaction vessel there was added the ~ollowing recipe:
Vinyl chloride 100 parts Water (demineralized)180 parts Methocel* (trademark) o.o6 part

2,2'-azobis-(2,4-dimethyl-valeronitrile) 0.075 par*
* Hydroxypropyl methyl cellulose Dow Chemical Company The reaction was carried out in the usual manner under a blanket o~ nitrogen and pressure with agitation. The temper-ature o~ the polymerization was 56C. and the reaction was con-tinued until a sub~tantial pressure drop occurred (approxl-mately 4.5 hours) indicating that the reaction was complete~
Thereafter, the contents of the reactor were removed in usual ~shion. A ~econd run in said reactor was made as above and the contents removed and the internal coated surfaces o~ the reactor were closely examined. The coat~ng was intact and essentially unchanged. The s~rfaces were classl~ied as clean, that is 9 with no polyvinyl chloride particles thereo~.
~hen the same recipe, as given above, was polymerized under the same conditions in a reactor which had not been coated internally, a heavy ~ilm of polymer being very rough in spots built up on the walls. Thus, the coatlng o~ the instant in~entlon alleviates this di~iculty.
EXAMPLE II
In this Example the procedure of Example I was ~ol-lowed in making the polyaromatic amine for the coating except that the molar ratio o~ m-PDA to R was 1.0 and the amount of HCl catalyst was 0~10 per mole o~ m-PDA. The temperature o~
the reaction mixture was raised to 315C. and held there ~or s 1 hour. The resultant polyaromatic amine had a softening point o~ 96C. The polyaromatic amine was then dissolved in Cello-solve to give a l.O~ by weight coating solution. The inner ; surfaces of the polymerization reactor were coated as in ; 5 Example I and the same polymerization recipe was employed.
The same reaction conditions were used and ~Our charges or runs were made prior to examining the inner walls. The coating was essentially unchanged and the surfaces were classified as clean with very few polyvinyl chloride particles thereon.
EXAMPLE IIT
The polyaromatic amine, prepared as in Example II, was employed in this Example. The polyaromatic amine was dis-solved in dimethyl ~ormami~e to give a 2.0% by weight coating solution. One half of the inner wa:Lls of the polymerization reactor was painted with the coating solution and dried by means of heat. The rest of the inner wall was left uncoated as a control. In the polymerization of vinyl chloride, the same recipe9 aæ used in Example I, was employed. The same reaction conditions were used and five charges or runs were ~ 20 made. A~ter each run the inner wall was examined with the - following results:
PVC Polyaromatic amine Uncoated Wall Run No. Coated Wall _ (Control) 1 Clean Fi~m 2 Clean Heavier film

3 Clean Thin even coating o~
polymer 4A few scattered Heavy, even coating sand spots of polymer 5Scattered sand Very heavy coating spots of polymer, horny in places It can be seen that the coating of the present in-vention greatly improves the polymer build-up situation.
EXAMPLE IV
In this Example a quantitative determination o~

- 18 _ 647~S
build-up was made. The polymerization conditions o~ E~ample I
were employed except that the polymerization recipe was as ~ollows:
Vinyl chloride 100 parts Water (demineralized)182 parts Polyvinyl alcohol 0.10 part 2,Z'-azobis-(2,4-dimethyl-valeronitrile~ 0.075 part Two stainless steel pla~ues measuring 1-1/2 inches by 2-1/2 inches by 1/4 inch were immersed in the reactor during the pol~merization. One plaque was coated with the coating described in Example III, namely, a 2~ solution of the poly-aromatic amine in dimethyl~ormamide. The other pla~ue was un-treated and served as a control. Both plaques were weighed 1~ before immersion in the reaction mixture and weighed again when removed from the reactor upon completion of the polymerization reaction, The results were as ~ollows:
Control (~ncoated) 0.09 gram weight gain Polyaromatic amine 0.01 gram weight gain (coated) This shows the large difference in polymer build-up between coated and uncoated surfaces in polymerization reactors.
EXAMPLE V
In this Example, the self-condensation product of m-phenylenediamine (m-PDA) was employed, This product was made by charging 109 grams o~ m-phenylenedlam~ne to a M ask equlpped with a re~lux condenser and heating to a temperature of 200C. Then 0.5 gram of AlC13 catalyst was added and the temperature raised to 250C. The reaction was continued ~or 11 hours and the NH3 coming off was collected in a water trap.
Therea~ter the reaction mixture was vacuum distilled in order to remove any unreacted dlamine therefrom. The recovered con-densed m-phenylenediamine was then dissolved in dimsthyl~orm-amide to give a 2.0% by weight coating solution. The inner sur~aces o~ a polymerization reactor were coated by brushing 1~6g7~5 the solution thereon with an absorbent pad and dr~ing by means o~ heat and circulating air.
To the coated reaction ve~sel was added the recipe o~ Example I with the exception that 0.05 part of catalyst (2,2~-azobis-(2,4-dimethylvaleronitrile) was used. The poly- -merization reaction was then carried out as described in Ex-ample I. After completion o~ the reaction, the polymer was removed therefrom in usual fashio~, the internal sur~aces were washed with water and a second run made. The same procedure was ~ollowed and a third run made. At thP end o~ the third run it was noted that the coating was intact and essentially unchanged. The same number o~ runs were made in an uncoated reactor as a control. The condition o~ the internal coated sur~aces were examined a~ter each ~m with the following re~
sults:
TABLE I
Uncoated Coated After 1st Light paper build- Clean - only one charge: up on part o~ sur- spot o~ paper ~aces build-up ~` After 2nd Same Same charge:
A~ter 3rd Completely coated Band o~ paper charge: with paper build- build-up on 1/3 up of sur~ace area From these results, the superiority o~ the coated surfaces over the uncoated sur~aces is readily apparent.
EXAMPLE VI
In this Example, the sel~-condenæation product o~
p-aminop~enol (p-AP) was employed. The product was made by charging to a three neck ~lask 109 grams of p-AP and 8.3 cc's o~ concentrated ~Cl, said flask being equipped with a con-denser. The flask was then heated and when the temperature reached 169C., 180 cc's o~ xylene were slowly added to the ~91785 reaction mixture. The purpose of the xylene was to remove the water formed during the condensation reaction as an azeotrope.
; The heating was continued for a period of thre~ hours to a maximum o~ 222C. Thereafter the mixture was cooled and washed with dilute HCl and the a~ueous phase decanted off.
The remainder was then ~acuum stripped to remove any unreacted materialO Upon cooling, the product became a solid which was then broken up into a fine granular condition~ given a water wash, ~iltered and dried. The ~lnal product (condensed p~
aminophsnol) was dissolved in d~methyl~ormamlde to give a 1.0%
by weight coatlng solution. This solution was then used in coating the inner surfaces o~ a polymerization reactor, as in Example V.
Using the recipe of Example I, a polymer was made in the coated vesse~ in two successive charges using a water rinse bet~een charges, as in Example V. Two runs were also made in an uncoated reactor as a control. The condition of the inter-n~l coated sur~aces were examined aeter each run with the following results:
TABLE II
Uncoated Coated - A~ter 1st Light paper build- Absolutely clean charge: up A~ter 2nd Eeavier paper Clean except ior charge: build-up a few spots of sandy build-up Again, the superiority of the coated surfaces is readily apparent~
EXAMPLE VII
In th~s Example, a numb~r o~ polyaromatic aminss were made using the procedure hereto~ore described in Example I. It will be noted that some o~ the polyaromatic amines are self-condeneed products while the others are reaction products of two o~ the compounds described herein. The poly-aromatic amines were made by condensing the compounds with the use of heat and HCl as a catalyst. The polyaromatic amines were dissolved in various organic solvents, as indicated in the Table below, and applied to the interior surfaces of a polymerization reactor, as in Example V. The recipe of E~am-ple VI was polymerized in the reactor in each case as well as i~ an uncoated reactor for the purpose o~ a control. Two charges were polymerized in each case without cleaning thP
reactor ~etween charges. The condition of the internal coated sur~aces were examined after each charge or run with the fol-lowln~ results:

, :`

~06~7~3S

G) ~ ~
~ ~ æ
,1 ~ æ
æ ~ x ~I h rl h S~ ~ ~ h h ~ S:~
O ~ ~ ~ O
~ ~ æ ~ ~ ~ o ~ ~ ~ a) ~ o æ
bO ~ ~ a) a) a) o ~ ~
~ æ æ ~ ~ a) h æ
v~" p, >, ~,~ h ~ C ~ h ~ X C~ O a) ~I
~J 0~ h~ ~V ~ D h~ ~
0 ~ h S- h $-1 ~3 h ~ 0 h h h h a) ~ 3 3 h ~ ~ -o ~ a) o ~1~ o c~ o o ~ h o ~ v ~ ~ ~ V ~ ~ ~Q V q~
P~
I
td co 0 ~ h 0 ~ O ~ O
c) ~c~ æ æ æ æ æ æ æ
SI H r~ l H r~ h ~1 ~ r~1 H rl r~ H
V ~ h h ~ h h h ~ ! ~ h h h h :~a h h r-l h H ~1 ~3 ~ a~ O a) ~ Q) a~ a) h ~R $~l a) o ~ a) ~ o o P, ~ o H ~ ~ bD S-l h h h h h S~ h h h h h h h ~:: ~ h o P o ¢ ~ v m C~
~f ~ ~o E~
o~

. ~ a~
. 5 1 0 0 0 0 0 0 0 0 ~ ~
` O ~ ~ O
~Q ~ ~ O

~ ~ o a) Q) ~;: h ~ ¢ rJ ~ m ~ o ~ o o o ~ ~ o ~d ~ ." o,'oi o ~ ~ ~ ~D ~ ~0 ~ ~ $
c) ~ ~ ~ ~ ~ ~ ~ a) o ~ c) c~ o c) .~1 ~ ~ ~rl C~ C~ O O ~ h bD ei h h~ S:: ~ h h ~ h ~ ~3 a.) ~ h h s2~ o oo o o ^~1 ~ H o o ~3 ~ ~ ~,~ h ~ ra ~C~ oro ~ 0~ ~q æ ~ p~ h-rl 5~ h æ ~
h $ ~h~ rl O
a~ ) a) ¢ ¢ ¢ cC ¢ ¢ c~ CC ¢ cl ¢ a~, ¢
P: O ~ ; 0 4-1 ~ O
o ~ ' ' ' ' I ' I I I I I I o ~ ~ o a P~ ~ ~ ~ ~ ~ ~ O ~E~

~;4785 The new and unexpected results of the Yarious coat-ings is ~pparent ~rom the above results.
EXAMPLE VIII
The purpose o~ thls Example was to show tha~ certain low molecular weight ~mines or monomeric compounds are not e~ective in preventing polymer build-up on the interior sur-~aces o~ a polymerization reaction vessel. As in Example IV, a quantitative determination of bulld-up was made. The ~ol-lowing polymerizati-on recipe was used ~n each experiment:
Vinyl chloride 40 lb ; Water (demineralized) 72.8 lb Methyl cellulose~45 gms. o~ 2%
H20 Soln~
Dl-sec-butyl peroxy-dicarbonate5.45 gms.
Stainless æteel plaques measuring 1-1/2 inches by 2-1/2 inches by 1/4 inch were coated with a 1~ solution of the var~ous amines in an organic solvent, as indicated in the Table I~ below. In each case an uncoated plaque was used as a controlO The plaques were weig~ed prior to immer~;ion in the polymerizatio~
medium and the polymerization reaction was conducted at 56C.
under pressure. The polymeriza~ion was continued until the pressure decreased by 10 psig. The plaques were then removedJ
washed and driea, and t~en weighed to determine the gain in weight due to polymer build-up. The data is set forth in the ~ollowing Table:

:~`

1~6~ S

h ~ h h a~ a I
0~ 0 ~+
P~l h qJ
1 0 a tl3 h + ~
~ c~ ~ ~D tlO bD ~D
td h bO ~rl~ri ~rl rl P~ ~h + + + +
O O h a a ~
o P a~
~ a) ~5 ~q ~ ~ ~ ~4 ~

~ 8 ~
oo ~ ~o~
C~J~ 00 00 .. .. ..
:~ oo oo oo o C~ C) ,, ~ ~ ¢

a) ~ ,, ~ ,1 ~ P, a~ ~ ~ 0 o~ o a~ o ~

,, 7~35 It can readily be seen ~rom the above results that some amines do not prevent build-up. While diphenylamine had some e~ect, it shows that low molecular weight materials do not do the job.
EXAMPLE IX
In this Example, the condensation product of m-phenylenediamine (m-PDA) and 4-chlororesorcinol was employed.
The product was made by charging to a three neck ~lask, equipped with a reflu~ condenser and a stlrrer, 16 2 grams of m-phenylenediamine and 21.7 grams o~ 4-chlororesorcinol. This was an equimolar ratio of the ingredients. Then 1.3 ml. o~
HCl catalyst was added and the contents heated to 275~. with stirring and held at this temperature for 1/2 hour. The pro-duct was then removed and dissolved in methyl alcohol to give a 1% by weight coating solution. The inner sur~aces o~ a poly-merization reactor were coated with said solution by brushing , it on with an absorbent pad and dr~iLng by means o~ heat and circulating air.
To the coated reaction ve~sel, the following recipe was added:
Vin~l chloride 80 lbs.
Wate~ (demineralized)144 lbs.
Methyl cellulose o.o48 lb.
Di-secondary butyl peroxydicarbonate o.o24 lb.
The reaction was carried out in the usual manner under a blan-ket o~ nitrogen with pressure and agitation. The temperature was maintained at 56C. and the reaction was continued until a substantial pressure drop occurred indicating that the reac-tion was complete. A~ter the contents of the reactor were re-moved in usual fashion, the internal sur*aces were examined - and found to be absolutely clean o~ polymer build-up. A
second run in said reactor was made as above, the contents removed and the sur~aces examined. Again the sur*aces were ~(~647~35 absolutely clean of polymer build-up~
When the same recipe, as given above, was polymerized under the same conditions in an uncoated reactor, a~ter the ~irst charge there was a light haze on the internal sur~aces, and after the second charge said surfaces were covered with a light paper build-up. It can be seen that the coating elimin-ates the problem o~ build-up.
Coating of the internal sur~aces o~ a polymerization vessel or reactor in accordance with the present invention substantially reduces polymer build-up and thus results in increased production over a unit period of t~me. In those instances where a little polymer does accumulate on the inter-ior sur~aces, it is not of the hard, rough, difficult-to-remove type and is easily removed by rinsing said surfaces with water, such as by hosing them down, without employing the dif~icult tedious scraping methods that are presently necessary in the art.
Most important, the present invention ena~les one to produce multiple batches o~ polymers in a reactor without hav-ing to open the same between charges. In the case o* poly-meriz~ng or copolymerizing vinyl chloride~ this ~r~atly redùces the parts per million of vinyl chloride in the atmosphere in the plant thus ~acilitating the ability of a PVC producer to meet the new Government standards with respect to vinyl chlor-ide. Further, with the reduction o~ pol~mer build-up, higher quality polymers are produced. Numerous other advantages o~
the present invention will be apparent to those skilled in the art.
While the present invention has been described in terms o~ its speci~ic embodiments, certain modifications and e~uivalents will be apparent to those skilled in the art and are intended to be included within the scope of the present invention, which is to be limited only by the reasonable scope of the appended claims.

, ; - 28 -"

Claims (49)

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

1. A polymerization reaction vessel having on the internal surfaces thereof a coating comprised of a polyaromatic amine having the structure selected from (I) wherein A, B and C are selected from the group consisting of a) wherein R3 and R4 may be the same or different and are selected from -H, -OH, -NH2, halogen, or an alkyl group containing from 1 to 8 carbon atoms: H
and R5 is N- or a straight chain or branched alkylene or alkylidene group containing from 1 to 5 carbon atoms; and b) wherein R3 and R4 are as defined above;
and wherein A, B and C may be the same or different and each repeating unit may be the same or different;
R1 and R2 may be the same or different and are selected from the group consisting of -H, -OH, -NH2 and wherein R3 and R4 are as defined above;
and x is an integer from 1 to 20; and y is an integer from 0 to 20; and (II) wherein A, B, R1, R3, R4 and R5 are the same as in (I); and R2 is -H, -OH or wherein R3 and R4 are as defined above; and x is an integer from 1 to 4; and y is an integer from 1 to 15, said polyaromatic amine being straight chained or branched and having a molecular weight greater than about 250.

2. A polymerization reaction vessel as defined in claim 1, wherein the polyaromatic amine has the structure (I).

3. A polymerization reaction vessel as defined in claim 1, wherein the polyaromatic amine has the structure (II).

4. A polymerization reaction vessel as defined in claim 1, wherein the polyaromatic amine is the reaction product of a poly-amino benzene having the formula wherein R1 and R2 are selected from the group consisting of -H, -NH2, -OH, halogen and an alkyl group containing from 1 to 8 carbon atoms, and may be the same or different, and a polyhydric phenol having the formula wherein R3 and R4 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different.

5. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is the reaction product of a polyamino benzene having the formula wherein R1 and R2 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and a compound selected from diphenyl-amines, alkyl-substituted diphenylamines and other compounds all having the formula wherein R is -N- or a straight chain or branched alkyl group containing from 1 to 5 carbon atoms; and R1, R2, R3 and R4 may each be -H, -NH2, -OH, halogen or an alkyl group contain-ing from 1 to 8 carbon atoms and at least 2 of which are -NH2 or -OH or one of each.

6. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is the reaction product of a polyamino benzene having the formula wherein R1 and R2 are either -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and R2 is -H, halogen or an alkyl group as defined for R1, and an aminophenol or an alkyl-substituted aminophenol having the formula wherein R5 and R6 are either -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different.

7. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is the reaction product of an amino phenol having the formula wherein R5 and R6 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and a compound selected from diphenyl-amines, alkyl-substituted diphenylamines and other compounds all having the formula wherein R is ? or a straight chain or branched alkyl group containing from 1 to 5 carbon atoms; and R1, R2, R3 and R4 may each be -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and at least 2 of which are -NH2 or -OH or one of each.

8. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is the reaction product of a polyhydric phenol having the formula wherein R3 and R4 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and a compound selected from diphenyl-amines, alkyl-substituted diphenylamines and other compounds all having the formula wherein R is ? or a straight chain or branched alkyl group containing from 1 to 5 carbon atoms, and R1, R2, R3 and R4 may each be -H, -NH2, -OH, halogen, or an alkyl group contain-ing from 1 to 8 carbon atoms and at least 2 of which are -NH2 or -OH or one of each.

9. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine has a molecular weight in the range of about 250 to about 2000.

10. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine has a softening point in the range of from about 65°C. to about 175°C.

11. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is a self-condensation product of any one of the compounds selected from polyamino benzenes, aminophenols, alkyl-substituted aminophenols; di-phenylamines, and alkyl-substituted diphenylamines, and any of said compounds having a halogen atom attached thereto.

12. A polymerization reaction vessel as defined in Glaim 1 wherein the polyaromatic amine is the condensation reaction product of more than two of the compounds selected from polyamino benzenes, polyhydric phenols, aminophenols, alkyl-substituted aminophenols, diphenylamines, and alkyl-substituted diphenylamines, and any of said compounds having a halogen atom attached thereto.

13. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is the reaction product of m-phenylenediamine and resorcinol.

14. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is the reaction product of m-phenylenediamine and bisphenol A.

15. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is the reaction product of o-phenylenediamine and resorcinol.

16. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is self-condensed p-amlnophenol.

17. A polymerization reaction vessel as defined in Claim 1 wherein the polyaromatic amine is self-condensed p-phenylenediamine.

18. A method of preparing a polymerization reaction vessel so as to substantially eliminate the build-up of polymers on the internal surfaces of the vessel which comprises applying to said surfaces a coating comprised of a straight chain or branched polyaromatic amine having a molecular weight greater than about 250 dissolved in an organic solvent therefor, said polyaromatic amine having the structure (I) wherein A, B and C are selected from the group consisting of a) wherein R3 and R4 may be the same or different and are selected from the group consisting of -H, -OH, -NH2, halogen and an alkyl group containing from 1 to 8 carbon atoms; and R5 is ? or a straight chain or branched alkylene or alkylidene group contain-ing from 1 to 5 carbon atoms: and b) wherein R3 and R4 are as defined above, and wherein A, B, and C may be the same or different and each repeating unit may be the same or different; R1 and R2 may be the same or different and are selected from the group consisting of -H, -OH, -NH2 and x is an integer from 1 to 20; and y is an integer from O to 20; and (II) wherein A, B, R1, R3, R4 and R5 are the same as in (I); and R2 is -H, -OH, or wherein R3 and R4 are as defined above; and x is an integer from 1 to 4; and y is an integer from 1 to 15.

19. A method as defined in claim 18, wherein the poly-aromatic amine has the structure (I).

20. A method as defined in claim 18, wherein the poly-aromatic amine has the structure (II).

21. A method as defined in claim 18, wherein the poly-aromatic amine is the reaction product of a polyamino benzene having the formula wherein R1 and R2 are either -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different: and a polyhydric phenol having the formula wherein R3 and R4 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be -the same or different.

22. A method as defined in Claim 18 wherein the polyaromatic amine is the reaction product of a polyamino benzene having the formula wherein R1 and R2 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and a compound selected from diphenyl-amines, alkyl-substituted diphenylamines and other compounds all having the formula wherein R is ? or a straight chain or branched alkyl group containing from 1 to 5 carbon atoms; and R1, R2, R3 and R4 may each be -H, -NH2, -OH, halogen or an alkyl group contain-ing from 1 to 8 carbon atoms and at least 2 of which are -NH2 or -OH or one of each.

23. A method as defined in Claim 18 wherein the polyaromatic amine is the reaction product of a polyamino benzene having the formula wherein R1 and R2 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and an aminophenol or an alkyl-substituted aminophenol having the formula wherein R5 and R6 are either -H, -NH2, -OH, halogen, or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different.

24. A method as defined in Claim 18 wherein the polyaromatic amine is the reaction product of an aminophenol or an alkyl-substituted aminophenol having the formula wherein R5 and R6 are either -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and a compound selected from diphenyl-amines, alkyl-substituted diphenylamines and other compounds all having the formula wherein X is ? or a straight chain or branched alkyl group containing from 1 to 5 carbon atoms; and R1, R2, R3 and R4 may each be -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and at least 2 of which are -NH2 or -OH or one of each.

25. A method as defined in Claim 18 wherein the polyaromatic amine is the reaction product of a polyhydric phenol having the formula wherein R3 and R4 are either -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and may be the same or different; and a compound selected from diphenyl-amines and alkyl-substituted diphenylamines and other compounds all having the formula wherein R is ? or a straight chain or branched alkyl group containing from 1 to 5 carbon atoms; and R1, R2, R3 and R4 may each be -H, -NH2, -OH, halogen or an alkyl group containing from 1 to 8 carbon atoms and at least 2 of which are -NH2 or -OH or one of each.

26. A method as defined in Claim 18 wherein the coating solution contains from about 0.10% to about 10.0% by weight of the polyaromatic amine.

27. A method as defined in Claim 18 wherein the organic solvent is dimethylformamide.

28. A method as defined in Claim 18 wherein the organic solvent is the monoethyl ether of ethylene glycol.

29. A method as defined in Claim 18 wherein the organic solvent is methyl alcohol.

30. A method as defined in Claim 18 wherein the polyaromatic amine has a molecular weight in the range of about 250 to about 2000.

31. A method as defined in Claim 18 wherein the polyaromatic amine is a self-condensation product of any one of the compounds selected from polyamino benzenes, aminophenols, alkyl-substituted aminophenols, diphenylamines, and alkyl-substituted diphenylamines, and any of said compounds having a halogen atom attached thereto.

32. A method as defined in Claim 18 wherein the polyaromatic amine is the condensation reaction product of more than two of the compounds selected from polyamino benzenes, polyhydric phenols, aminophenols, alkyl-substituted aminophenols, diphenylamines, and alkyl-substituted diphenylamines, and any of said compounds having a halogen atom attached thereto.

33. A method as defined in Claim 18 wherein the polyaromatic amine is the reaction product of m-phenylene-diamine and resorcinol.

34. A method as defined in Claim 18 wherein the polyaromatic amine is the reaction product of m-phenylene-diamine and bisphenol A.

35. A method as defined in Claim 18 wherein the polyaromatic amine is the reaction product of o-phenylene-diamine and resorcinol.

36. A method as defined in Claim 18 wherein the polyaromatic amine is self-condensed p-aminophenol.

37. A method as defined in claim 18, wherein the poly-aromatic amine is self-condensed p-phenylenediamine.

38. In a process for the polymerization of olefinic mono-mers the improvement which comprises polymerizing the monomer or monomers in an aqueous polymerization medium and keeping said medium in constant contact throughout the polymerization reaction with a surface having thereon a water-insoluble coating comprised of a polyaromatic amine having a structure selected from the group consisting of (I) wherein A, B and C are selected from the group consisting of (a) wherein R3 and R4 may be the same or different and are selected from the group consisting of -H, -OH, -NH2, halogen aHd an alkyl group containing from 1 to 8 carbon atoms and R5 is ? or a straight chain or branched alkylene or alkylidene group contain-ing from 1 to 5 carbon atoms; and (b) wherein R3 and R4 are as defined above; and wherein A, B and C
may be the same or different and each repeating unit may be the same or different, R1 and R2 may be the same or different and are selected from the group consisting of -H, -OH, -NH2 and wherein R3 and R4 are as defined above; and x is an integer from 1 to 20; and y is an integer from 0 to 20; and (II) wherein A, B, R1, R3, R4 and R5 are the same as in (I) and R2 is -H, -OH or wherein R3 and R4 are as defined above; and x is an integer from 1 to 4, and y is an integer from 1 to 15, said polyaromatic amine being straight chained or branched and having a molecular weight greater than about 250, whereby due to said coating, polymer build-up on said surface is substantially eliminated.

39. A process as defined in claim 38, wherein the monomer is vinyl chloride.

40. A process as defined in claim 38, wherein the poly-merization reaction is conducted at a temperature in the range of 0°C. to 100°C.

41. A process as defined in claim 38, wherein the poly-aromatic amine is a self-condensation product of any one of the compounds selected from polyamino benzenes, aminophenols, alkyl-substituted aminophenols, diphenylamines, and alkyl-substituted diphenylamines.

42. A process as defined in Claim 38 wherein the polyaromatic amine is the condensation reaction product of more than two of the compounds selected from polyamino ben-zenes, polyhydric phenols, aminophenols, alkyl-substituted aminophenols, diphenylamines, and alkyl-substituted diphenyl-amines.

43. A process as defined in Claim 38 wherein the polyaromatic amine is the reaction product of m-phenylene-diamine and resorcinol.

44. A process as defined in Claim 38 wherein the polyaromatic amine is the reaction product of m-phenylene-diamine and bisphenol A.

45, A process as defined in Claim 38 wherein the polyaromatic amine is the reaction product of o-phenylene-diamine and resorcinol.

46. A process as defined in Claim 38 wherein the polyaromatic amine is self-condensed p aminophenol.

47. A process as defined in Claim 38 wherein the polyaromatic amine is self-condensed m-phenylenediamine.

48. A process as defined in Claim 43 wherein the monomer is vinyl chloride.

49. A process as defined in Claim 48 wherein the temperature of polymerization is in the range of about 40°C.
to about 70°C.