CA1114968A - Composition for the clarification and detackification of paint spray booth wastes - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
An improved method for the clarification and detackification of oversprayed paint and lacquer solids is disclosed. Utilizing conventional treatment methods for this type of waste, a water soluble cationically charged polymer and a water-soluble salt of an amphoteric metal at an alkaline pH, superior recovery of the oversprayed paint and lacquer solids are obtained by additionally treating the waste with a water immiscible hydrocarbon liquid. This causes the waste to float, allowing for better recovery, and a water of superior clarity.

Description

In thc application of paints and lacquers to automobile bodies and other types of articles, it is customary to carry out such operations in enclosed spray booths and to introduce into such spray booths a curtain of water to wash the air and to remove oversprayed paints or laequer solids.
The water containing suspended solids is filtered or otherwise treated to separate the solids so that the water can be recycled.
This process involves many problems. Thus, the paint and lacquer solids are normally tacky and tend to adhere to the walls, ceilings, and floors of the spray booths which makes it necessary to shut down the oper-ation from time to time in order to clean the spray boothsO The deposits which are formed on the walls, ceilings, and floors of the spray booths are also subject to the growth of anaerobic corrosive bacteria (e.g., desulfovibrio) which generates corrosive and highly objectionable hydrogen sulfide.
The paint and lacquer solids which are washed away and formsuspensions in the water that is removed from the spray booths present a disposal problemO In order to avoid contamination of the environment, it is customary to separate these solids from the water and to recirculate the water, but these solids are difficult to separate by the usual method of filtrationO
It is~ therefore, desirable to control pollution and contamina-tion in paint and lacquer spray booths so as to prevent, as much as possible the deposition of paint and lacquer solids on walls, ceilings, and floors and to condition the sludge which is removed with the water so that it can be readily filtered and the water which forms the filtrate can be returned . ,. - ~
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for use in the process.
The prior art has shown that water used to wash the air in paint or lacquer spray booths in order to remove and detackify oversprayed paint and lacquer can be treated with a blend of a polycationic water-soluble polymer in conjunction with a water-soluble salt of an amphoteric metal.
This type of treatment, shown in United States Patents: 3,861,887;
3,990,869; and 4,o67,806~ has gained considerable commercial acceptance.
Apparently, the function of the cationic water-soluble polymers is to neutralize the anionic charge on the paint or lacquer droplets contained in the water and the amphoteric metal is precipitated under aIkaline con-ditions to form a floc of the oversprayed paint and lacquer solids.
United States 3,990,986 shows the use of a blend of primary amino alcohols and a polyether polyamine in conjunction with the water-soluble salt of an amphoteric metal for the same purpose.
United States 4,022,490 shows the use of a composition consisting of a low molecular weight polypropylene glycol to increase the operational efficiency of cationic polymer-amphoteric metal combinations for the removal of oversprayed paint and lacquer solids from p~int spray booth water systemsO
Other references include United States 4,029,708 which discloses various linear surfactant polymers formed by the reaction of a substituted amine in a difunctional reactant in combination with water soluble amphot- -eric metal salts. Another reference disclosing the treatment of paint or lacquer spray booths in United States 4,o55,495 which shows capped polyether polyamines in conjunction with an amino alcohol and a water soluble amphot-eric metal salt for the clarification and detackification of paint spray booth wastes.
A still further reference is United States Patent 4,o67,806, which discloses the use of an acrylamide-diallyl dimethyl ammonium chloride N-vinyl-pyrrolidone terpolymer in conjunction with the water-soluble salt of an amphoteric metal for the treatment of paint and lacquer overspray.
While the prior art has been successful in the treatment of paint spray booth wastes, a serious problem has existed as to the removal of the detackified and flocculated oversprayed paint and lacquer solids. Often-times these materials have remained suspended in the paint spray booth wash water and oftentimes they have even settled to the bottom of the water sumps which have collected the paint spray booth wastes, forming a sludge which is difficult to remove. This renders processes of these types somewhat less efficient, and it would be desirable to improve these process-es so as to enable a better recove~ry of the oversprayed paint and lacquer solids from processes of this typeO
This invention seekst~pr~v~idei~an~i~r~vi~d-!p~ ss fi~rltke-~regov-ery of paint and lacquer solids from water wash paint spray booths.
In particular this invention seeks to provide an improved method for the recovery of oversprayed paint and lacquer solids which have been treated with a water soluble cationic polymer and a water-soluble salt of an amphoteric metal from paint spray booths.
Alternatively, this invention seeks to provide a novel additive for water wash paint and lacquer spray booths to be used in conjunction with a water soluble cationic polymer and a water-soluble salt of an ampho-teric metal whereby the solids are floated to the top surface of the paint ~ . . ~

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spray booth sump and can be skimmed or recovered from the paint spray booth wash water.
This invention generally encompasses a method for the clarification and detackification of oversprayed paint and lacquer from uater wash paint spray booths which process comprises adding to the water being circulated in the paint spray booth a water soluble cationic polymer and a water-soluble salt of an amphoteric metal in a quantity sufficient when used in conjunction with an alkaline pH control aid to cause detackification and coagulation ofthe oversprayed paint and lacquer solids; and adding to the water being recirc-ulated in the paint spray booth a water im~;scible hydrocarbon liquid having a specific gravity of less than one and a boiling point greater than that of water in sufficient quantity to float the detackified and coagulated oversprayed paint and lacquerlsolids whereby the oversprayed paint and lac-quer solids are floated to the top surface of the paint booth wash water.
In a more preferred embodiment the invention comprises an improved method for the clarification and detackification of oversprayed paint and lacqu~r from water in water wash paint spray booths ~Ihich process comprises adding to the water being circulated in the paint spray booth a water $ol-uble cationic polymer and a water-soluble salt of an amphoteric metal in a quantity sufficient to cause detackification and coagulation of the over-sprayed paint and lacquer solids; and adding to the water being recirculated in the paint spray booth an emulsion composition comprising:
A. 5.0-50% by weight of a water immiscible hydrocarbon liquid having a specific gravity of less than one and a boiling point above that of water;
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B. 5~-95% by weight of a 10-60% by weight aqueous solution of an alkali metal hydroxide;
in a quantity sufficient to float the detackified and coagulated overspray paint and lacquer solids and to maintain the paint spray booth wash water at an alkaline pH value, whereby the oversprayed paint and lacquer solids are floated to the top surface of the paint spray booth wash water.
Thus the floating paint and lacquer solids can be recovered and removed from the paint spray booth wash water.
The hydrocarbon liquids useful in this invention are water im-miscible, have a specific gravity of less than one and preferably have a boiling point above that of waterO Examples of such hydrocarbon liquids include fuel oils, such as the No. 2 and No. 6 grades kerosene, paraffin oils, heavy aromatic oils, mineral seal oils and the like. As will readily be seen, the exact chemical composition of the oil is unimportant so long as it generally meets the above requirements and is fluid at the temperature encountered in spray booth operations. As an example, when using heavy fuel oils such as No~ 6 fuel oil, the mixture must often be diluted with a lower viscosity fraction such as kerosene~ to increase the fluidity and ease the handling of this ingredient of the inventionO
While a boiling point above that of water has been stated to be a property of the compounds of the instant invention, it will bee seen that this is a preferred parameter only due to environmental and safety consider- ~
ations. In the actual performance of this invention any hydrocarbon liquid having a specific gravity less than that of one, so that it will float to the surface of the water it is mixed with, will perform in this invention.
_ _ _5_ The fact t~lat the hydrocarbon liquid be water immiscible is an important property of the hydrocarbon liquid and thus solvents such as acetone would not perform in this inventionO
When the paint spray booth treatments of this invention are util-ized, it is important that the pH of the water in the paint spray booth be alkaline. The most important reason for this is to precipitate the hydrox-ide of the amphoteric metal added as a water-soluble salt in the treatment formulations. Generally, any alkaline pH control aid will serve this pur-pose. The preferred alkaline pH control aids are sodium and potassium hydroxides, preferably utilized as 10-60% aqueous solutions. In the actual use of the compositions of the instant invention, the pH of the paint spray booth wash water is adjusted to between 7.0-11 and preferably from 7.5-10.5 by the continuous addition of the alkaline pH control aid. Most preferably the pH will range from 805-10.5. Continuous addition of the alkaline pH
control aid is important since the hydroxide ion is precipitated from the solution by the amphoteric met~l. Thus~ in order to maintain the ~H with-in the desired range, the alkaline pH control aid must be regularly added.
The aationic water-soluble polymers employed in the practice of this invention are of well known types having a linear carbon chain to which is attached a plurality of cationic groups such as, for example, amino and quaternary amino groups. Polymers which have been found to be effective usually have a molecular weight within the range of 200 to 100,000 and higher. Examples of such polymers which are compatible with water-sol-uble salts of amphoteric metals are the polycondensates having a molecular weight of at least 1,000 of epichlorohydrin and precondensates of poly-_ _6-alkylene polyamines and polyoxyalkylene glycol chlorides as disclosed in United States Patent 3,251,882 and polyethylene polyamines as disclosed in United States Patent 3,751,474. Other suitable polycationic linear polymers are condensation products of ammonia and ethylene dichloride~ and conden-sation products of ethylene diamine and ethylene dichloride, and the quatern-ary salts thereof as disclosed in United States Patent 3,372,129. Suitable polycationic linear polymers for the purpose of the invention are also obtained by the polymerization of polyethylene glycol and hexamethylene-diamine. Similar polycationic water dispersible polymers having a linear main carbon chain with a plurality of cationic groups attached thereto which are compatible with water-soluble salts of amphoteric metals can be employed for the purpose of the invention.
Other useful cationic agents which will perform in our invention and are considered polymers for the purpose of our invention include sub-stituted amines having at least two primary amine groups and having at least three carbon atoms. Examples of compounds in this c;Lass include dipropylene triamine, hexamethylamine diamine, hexamethylene triamine and tetraethylene pentAmine. Additionally~ it may sometimes be desirable to use crude dis-tillation bottoms or overheads containing these materials such as bottDms from the distillation of hexamethylene diamineO
Also, the linear polyamine polymers of low molecular weight disclosed in United States Patent 3,468~818 may be used in the practice of the present invention.
Other water soluble cationic polymers which are useful within the scope of this invention include dichloride butene-dimethyl amine condensates ~ ~ ~ 4'~t~ ~

such as those disclosed in United States 3,928,448.
A particularly useful class of water-soluble polymers for use in this invention are polyether polyamines such as those described in United States 3,990,986. These polymers are generally prepared by the steps com-prising:
1. Reacting a polyalkylene oxide, selected from ethylene oxide, propylene oxide and butylene oxide with a lower difunctional epoxide selected from epichlorohydrin, epibromohydrin and epiiodohydrin, in a mole ratio of hydroxyl groups present on said polyaIkylene oxide to lower difunctional epoxide of from 0.5:1.0 to 1.0:0.5~ said polyalkylene oxide further charac-terized as having a molecular weight of from 100 to 1,000 whereby a capped polyalkylene oxide is formed;

2. Reacting the capped polyalkylene oxide of step 1 with a lower aliphatic amine having from 2 to 8 carbon atoms and two or more amino groups in a mole ratio of from 1:5 to 1:1 based on the number of amino groups present on the amine compound and the number of halogens on the capped polyaIkylene oxide; and then,

3~ Recovering the polyether polyamineO
More particularly, the polymers are prepared by the steps;
lo Reacting a polyalkylene oxide, selected from ethylene oxide, propylene oxide, and butylene oxide with a lower difunctional epoxide selected from epichlorohydrin, epibromohydrin, and epiiodohydrin in a mole ratio of hydroxyl groups present on said polyalkylene oxide to lower di-functional epoxide of from 005 loO to 1.0:0.5 said polyalkylene oxide fur-~her characterized as having a molecular weight of from 100 to 1,000 whereby . ~

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a capped polyalkylene oxide is formed;
2. Reacting the capped polyalkylene oxide of step 1 with a lower aliphatic amine having from 2 to 8 carbon atoms and two or more amino groups in a mole ratio of from 1:5 to 1:1 based on the number of amino groups present on the amine compound and the number of halogens on the capped polyalkylene oxide;
3. Reacting the polyether polyamine of step 2 with a cross-linking agent, selected from ethylene dichloride, ethylene dibromide, 1,4-dichloro-2-butene, propylene dichloride, and epihalohydrins in a mole ratio of cross-linking agent to amine functionally added in step 2 above of from 0.1 to 1.6 whereby a cross-linked polyether polyamine is formed, and then,

4. Recovering the polyether polyamine.
While it is noted that the above description of the water soluble cationic polymer generally encompasses those which are prepared by conden-sation polymerization techniques, cationic polymers which are water soluble and prepared by vinyl addition techniques are also useful. Among the polymers which may find application in this invention and which are prepared by vinyl addition techniques include:r..PolYdiallyl ~;methyl amine chloride (United States 3,288,770) and its copolymers with acrylamide and other non-ionic or cationic monomers; polymers and copolymers of dimethyl amino methyl methacrylate and its water soluble quaternary derivatives; and acrylamide or acrylamide copolymers which have been reacted by the marnich reaction to form cationically modified derivatives, and the corresponding quaternary derivatives.
It will be readily seen that the above examples are illustrative __ _9_ only and that other polymers having significant amounts of cationic charge will also perform adequately in this invention. It should be pointed out that the molecular weight of these polymers is a consideration and the mole-cular weight of the vinyl addition polymers employed should not be so high as to produce paint spray booth wash water having a noticeable viscosity increase. As a result, relatively low molecular weight polymers, those in the range of from several thousand to several hundred-thousand, are gener-ally preferred when polymers of this type are utilized in this application.
The water soluble amphoteric metal salts which are useful in the scope of this invention encompass all water soluble inorganic salts which will form floc-like hydroxide compounds at pH values greater than 7. While we prefer to use magnesium chloride in the scope of this invention due to its high water solubility and the fact that the chlorine ion presents no pollution problem, other magnesium salts can be used including magnesium sulfate and magnesium nitrate~ Additionally, aluminum chloride, aluminum sulfate, ferric chloride, ferric sulfate, zinc chloride, zinc sulfate and zinc nitrate all give satisfactory results when used with this invention.
It is understood that the above list is illustrative only, and does not encompass all metallic salts that will work in our inventionO Other metal salts work in our inventionD The essential requirement for the metal salt is that the particular cation will form an insoluble hydroxide at pH's greater than about 7 and that the anion in the salt will not cause pollution problems D
In the typical use of this invention a blend of the water soluble cationic polymer and water-soluble salt of an amphoteric metal is prepared.

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This blend is generally prepared by blending the polymer with a solution of an amphoteric metal salt generally within the range of 0.2 to 3 parts by weight of the amphoteric metal salt per part of the cationic water-soluble polymerO This composition is then generally added at a level of 2.0 to 100,000 ppm to the paint spray booth waste water. Since the com-position of the invention is expended during the normal treatment of water of this type, fresh material should be added to the water which has been clarified by this inventionO Preferred dosage ranges for the amphoteric metal-polymer blend is from 10-50,000 ppm, and most preferably from 15-20,000 ppm.
This part of the composition of the instant invention will gener-ally be added to the water before it enters the paint spray booth circuit so that the additive will be present in the water wash when the water wash in the paint spray booth contacts the oversprayed paint and lacquer solids.
This material is generally run down the walls of the paint spray booths, over grates, and all surfaces which are desired to be kept free of paint accumulationO After picking up the oversprayed paint or lacquer solids, the water returns to a sump or container where a coagulated and detackified paint and lacquer solid material is removedO
In the use of this part of the composition of this invention, the pH of the paint spray booth water should be alkaline. This is accomplished by adding to the water the alkaline pH control aids which have been dis-cussed earlier. This material is added so as to keep the pH of the paint spray booth wash water within the range of 7 to about 13.
The hydrocarbon oils, will generally be added to the paint spray ~4~

booth wash water in a quantity sufficient to float the oversprayed paint and lacquer solids to the top surface of the paint spray booth wash water so that these solids can be readily recovered. The quantity of hydrocarbon liquid added wi]l generally depend upon the amount of amphoteric metal salt added and the amount of oversprayed paint and lacquer solids present in the wash water. It is thus seen that a true quantitative figure cannot be given for the amount of hydrocarbon liquid to be added but it will be readily apparent to those skilled in the art that the amount of hydrocarbon liquid added can be readily determined by routine experimentationO All that is important is that the hydrocarbon liquid be added in an amount sufficient to float the coagulated and detackified paint and lacquer solids in the water wash paint spray booth.
In a preferred embodiment of this invention, the hydrocarbon liquid and the alkaline pH control aid are admixed to form an emulsion prior to their being added to the paint spray booth wash water. Emulsions of this type which pose a convenience as far as feeding the chemical to the paint spray booth wash water generally contain 5-50% by weight of the hydrocarbon liquid and 50-95~ by weight of a 10-60% by weight aqueous sol-ution of the alkaline pH control aid, preferably an alkali metal hydroxideO
The percentages listed above can be varied for the particular water employed and the conditions being dealt with so that the emulsion is added in sufficient quantity to float the detackified and coagulated over-sprayed paint and lacquer solids and maintain the pH of thepaint spray booth wash water at the alkaline pH values previously discussed.
In conjunction with this emulsion is oftentimes added a minor ' '`` ' amount, ranging from Ool to 5% by weight of the emulsion, of a surfactant or surfactant blend capable of stabilizing the hydrocarbon liquid-alkaline pH adjusting aid emulsion during shipment and storage. Examples of such surfactants include Toximul 600 , an emulsifer blend available from the Stepan Chemical Company, which is reported to be a blend of sulfonated and non-ionic surfactants. We have found that anionic surfactants generally perform well in the preparation of these emulsions. A particularly preferr-ed class of anionic surfactants are sulfonated alkyl phenols. It should be pointed out that those skilled in the art will be able to readily determine surfactants for this type of emulsion. It is expected that both surfactant types and levels will vary depending upon the alkaline pH control aid utilized and the exact hydrocarbon liquid employed in this invention, as well as the percentages of each component employed.
With the-!use of this invention, the blend of the cationic polymers and water soluble amphoteric metal salt serve to coagulate and detackify the oversprayed paint and lacquer solids. The hydrocarbon liquid serves to float the detackified and coagulated paint and lacquer solids to the surface of the paint spray booth water and the alkaline pH control aid serves to aid in the coagulation of the paint and lacquer overspray.
Prior to the utilization of this invention, the coagulated and detackified paint and lacquer solids would oftentimes settle to the bottom of the paint spray booth water sump or container causing severe cleaning problemsO Wlth the utilization of the instant invention, the paint and lacquer solids are floated to the top surface of this su~p and thus can be readily skimmed off and recovered.

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~4'~c Through further treatment of this skimmed off material~ the hydro-carbon liquid can generally be removed from the paint and lacquer solids and either be reused in the paint spray booth or alternatively burned as a fuel within the plant. With the use of this invention, paint spray booths employing the improvement of this invention will generally experience both less down time for cleaning and a superior cleaning of the paint and lacquer overspray from the paint spray booth wash water will be achieved.
The paint and lacquers to which this invention finds applicability include but are not limited to both solution and dispersion based enamels , dispersion and solution lacquers water borne paints~ and polyurethanes.
In order to show the utility of this improvement, the following examples are presented:
Example 1 In the following examples, the test procedure below ~as utilized:
Five hundred milliliters of water were added to a laboratory blender. With slow mixing, one milliliter~of the detackifier composition (cationic polymer-amphoteric metal salt) were added with slow stirring.
Following this, the alkaline pH control aid and hydrocarbon liquid were added to the desired pH range with mixing. Following this, paint was added in one-half milliliter quantities with slow stirring with a 30-second mix time for each addition. Paint addition was continued until tacky paint resulted. Compositions employed in Tables I and II are listed below:

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COMPOSITION A
% by weight 903 Approximately 50% aqueous solution of a polyamine similar to that described in Example 2 of United States 3,990,986 utilizing epichlorohydrin instead of 1~4-dichlorobutene-2 as cross-linking agent.
47.0 67% aqueous solution of zinc chloride 43-7 Water 10.0 Approximately 50% aqueous solution of a polyamine similar to that described in Example 2 of United States 3,990~986 utilizing epichlorohydrin instead of 1,4-dichlorobutene-2 as cross-linking agent.
9000 23% aqueous solution of aluminum chloride COMPOSITION C
2018.0 Polymer formed by condensing triethanolamine and quaternizing resultant composition with CH3Cl ~43% active).
48.2 50% aqueous solution of aluminum sulfate 33.8 Tap water COMPOSITION D
2102 Polymer prepared by condensing triethanol-amine and quaternizing resultant composition with CH3Cl (43% active).
45.0 67% aqueous solution of zinc chloride 3308 Tap water COMPOSITION E
11.0 NoO 6 fuel oil 8.o Deodorized kerosene 1~0 Toximul 600 _ _ ~^~rade Mark ,.. . .

. ': , , 80.0 50% NaOH solution COMPOSITION F
% by weight 19.1 Paraffin oil 0.25 Toximul 600 80.75 50% NaOH solution COMPOSITION G
1900 Heavy aromatic oil 0.25 Toximul 600 80.75 50% NaOH solution COMPOSITION H
19.0 Deodorized kerosene o o 25 Toximul 600 80~75 50% NaOH solution COMPOSITION I
1900 Mineral seal oil 0025 Toximul 600 80075 50% NaOH solution COMPOSITION J
13.0 Deodorized kerosene 3Do Paraffin wax 1.0 Toximul 600 83.o 503~ NaOH solution Visual observations in the tables below are given as to the quality of the detackified paint, the sludge~s floatability and water clarityO
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EXAMPLE II
The application to an automotive paint spray booth of a combin-ation of Chemical B and Chemical F discussed in Example I and a Chemical B/NaOH treatment were compared in the paint spray booth system of a large automotive assembly plant. Evaluation showed that the combination of Chemicals B and F proved very effective in the detackification and coag-ulation of oversprayed paint solids while the combination of Chemical B/
NaOH was not nearly as effectiveO The Chemical B/NaOH combination did not maintain a sufficient level of foam necessary to effectuate paint re-moval by filter screens while the Chemical B/F combination showed excellent activity yielding a stable foam layer resulting in good paint sludge remov-al through the use of filter screens.
In this evaluation, Chemical B was fed at a level of 1.75 gals.
per hour to the paint spray booth sump and Chemical F was fed at a rate of approximately lol gals. per hour to maintain a pH in the range of 908 to 1003 at the sump pump header. Caustic was fed at the same place as Chemical Fo EXAMPLE III
A Chemical B and Chemical E combination was compared against a Chemical B/NaOH treatment in the paint spray booth of a large automotive plant. The Chemical B/E treatment showed improved sludge floatability and water clarity over the Chemical B/NaOH treatment.

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Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method for the clarification and detackification of overspray-ed paint and lacquer from water in water wash paint spray booths which process comprises adding to the water being circulated in the paint spray booth a water soluble cationic polymer and a water-soluble salt of an am-photeric metal in a quantity sufficient, when used in conjunction with an alkaline pH control aid, to cause detackification and coagulation of the oversprayed paint and lacquer solids, and adding to the water being recirc-ulated in the paint spray booth a water immiscible hydrocarbon liquid hav-ing a specific gravity of less than one in sufficient quantity to float the detackified and coagulated oversprayed paint and lacquer solids whereby the oversprayed paint and lacquer solids are floated to the top surface of the paint booth wash water.

2. The process of claim 1 wherein the hydrocarbon liquid having a specific gravity of less than one is selected from the group consisting of No. 2 fuel oil, No. 6 fuel oil, mineral seal oil, heavy aromatic oil, par-affin oil, and kerosene.

3. The process of claim 1 or 2, wherein the water immiscible hydrocarbon liquid has a boiling point greater than that of water.

4. The process of claim 1 wherein the water soluble cationic poly-mer is selected from the group consisting of:
A. Polyether polyamines prepared by the steps comprising:

1. Reacting a polyalkylene oxide, said alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide and butylene oxide with a lower difunctional epoxide selected from the group consisting of epichlorohydrin, epibromohydrin and epiiodohydrin in a mole ratio of hydroxyl groups present on said polyalkylene oxide to lower difunctional epoxide of from 0.5: 1.0 to 1.0:0.5, said polyalkylene oxide further char-acterized as having a molecular weight of from 100 to 1,000 whereby a capped polyalkylene oxide is formed;
2. Reacting the capped polyalkylene oxide of step 1 with a lower aliphatic amine having from 2 to 8 carbon atoms and two or more amino groups in a mole ratio of from 1:5 to 1:1 based on the number of amino groups present on the amine compound and the number of halogens on the capped poly-alkylene oxide;
3. Reacting the polyether polyamine of step 2 with a cross-linking agent, said cross-linking agent selected from the group consisting of ethy-lene dichloride, ethylene dibromide, 1,4-dichloro-2-butene propylene dichlor-ide and epihalohydrins in a mole ratio of cross-linking agent to amine functionality added in step 2 above of from 0.1-1.6 whereby a cross-linked polyether polyamine is formed; and then 4. Recovering the polyether polyamine;
B. Ethylene dichloride-ammonia condensates;
C. Polydiallyl dimethyl ammonium chloride;
D. Polyacrylamide which has been subjected to the mannich reation;
E. Polyacrylamide which has been subjected to the mannich reation and quaternized;

F. Epichlorohydrin-dimethylamine condensates.

5. The process of claim 1 wherein the water-soluble salt of an amphoteric metal is selected from the group consisting of; zinc chloride, aluminum chloride, magnesium chloride, ferric chloride, aluminum sulfate, magnesium sulfate, ferric sulfate, and zinc sulfate.

6. The process of claim 1 wherein the alkaline pH control aid is selected from the group consisting of aqueous solutions of alkali metal hydroxides.

7. The process of claim 1 wherein the pH of the paint spray booth wash water is adjusted to a level of between 7.5-10.5 with the alkaline pH
control aid.

8. A method for the clarification and detackification of overspray-ed paint and lacquer from water in water wash paint spray booths which process comprises adding to the water being circulated in the paint spray booth a water soluble cationic polymer and a water-soluble salt of an am-photeric metal in a quantity sufficient to cause detackification and coag-ulation of the oversprayed paint and lacquer solids; and adding to the water being recirculated in the paint spray booth an emulsion composition comprising:
A. 5-50% by weight of a water immiscible hydrocarbon liquid having a specific gravity of less than one; and B. 50-95% by weight of a 10-60% by weight aqueous solution of an alkali metal hydroxide;

in a quantity sufficient to float the detackified and coagulated overspray-ed paint and lacquer solids and to maintain the paint spray booth wash water at an alkaline pH value, whereby the oversprayed paint and lacquer solids are floated to the top surface of the paint spray booth wash water.

9. The process of claim 8 wherein the emulsion composition comprises in addition to the hydrocarbon liquid and aqueous solution of an alkali metal hydroxide from 0.1 to 5% by weight of an alkali stable non-ionic or anionic surfactant.

10. The improvement of claim 8 wherein the water immiscible hydro-carbon liquid having a specific gravity of less than one is selected from the group consisting of No. 2 fuel oil, No. 6 fuel oil, mineral seal oil, heavy aromatic oil, paraffin oil and kerosene.

11. The process of claim 8 or 10 wherein the water immiscible hydrocarbon liquid has a boiling point greater than that of water.

12. The improvement of claim 8 wherein the alkali metal hydroxide is sodium hydroxide.

13. The process of claim 8 wherein the alkaline pH value is from 7.5 to 10.5.

14. The process of claim 8 wherein the water soluble cationic poly-mer is selected from the group consisting of:

A. Polyether polyamines prepared by the steps comprising:

1. Reacting a polyalkylene oxide, said alkylene oxide selected from the group consisting of ethylene oxide, propylene oxide and butylene oxide with a lower difunctional epoxide selected from the group consisting of epichlorohydrin, epibromohydrin and epiiodohydrin in a mole ratio of hydroxyl groups present on said polyalkylene oxide to lower difunctional epoxide of from 0.5:1.0 to 1.0:0.5, said polyalkylene oxide further char-acterized as having a molecular weight of from 100 to 1,000 whereby a cap-ped polyalkylene oxide is formed;

2. Reacting the capped polyalkylene oxide of step 1 with a lower aliphatic amine having from 2 to 8 carbon atoms and two or more amino groups in a mole ratio of from 1:5 to 1:1 based on the number of amino groups present on the amine compound and the number of halogens on the capped polyalkylene oxide;

3. Reacting the polyether polyamine of step 2 with a cross-linking agent, said cross-linking agent selected from the group consisting of ethy-lene dichloride, ethylene dibromide, 1,4-dichloro-2-butene, propylene di-chloride and epihalohydrins in a mole ratio of cross-linking agent to amine functionality added in step 2 above of from 0.1-1.6 whereby a cross-linked polyether polyamine is formed; and then,

4. Recovering the polyether polyamine;
B. Ethylene dichloride-ammonia condensates;
C. Polydially dimethyl ammonium chloride;
D. Polyacrylamide which has been subjected to the mannich reaction ;
E. Polyacrylamide which has been subjected to the mannich reaction and quarternized;
F. Epichlorohydrin-dimethylamine condensates.