CA1320417C

CA1320417C - Cleaner for treating a surface

Info

Publication number: CA1320417C
Application number: CA000613932A
Authority: CA
Inventors: Cassius W. Leys
Original assignee: AGP SYSTEMS, INC.
Current assignee: AGP SYSTEMS Inc
Priority date: 1989-08-30
Filing date: 1989-09-28
Publication date: 1993-07-20
Anticipated expiration: 2010-07-20
Also published as: EP0489863A1; WO1991003522A1; US5024780A; EP0489863A4; JPH05503951A; AU6414790A; AU642669B2

Abstract

ABSTRACT OF THE DISCLOSURE

The present cleaner removes graffiti, paint and other coatings, if any, from a surface. The cleaner comprises N-methylpyrrolidone;
propylene carbonate; hydroxy propyl cellulose thixotropic thickening agent; an ingredient selected from the group consisting of diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl ether, diethylene glycol ethyl ether and isocetyl alcohol; and a surfactant.

Description

13204~7 ~LEANER FOR TREATTNG A SURFACE

The present invention relates generally to a cleaner ~or t-eating a ~urface. Mo~e par~icul~rly, the present invention selates to such a cleaner which removes graf~iti from c~rtaln des~ed protect~ve coated or paint~d surface without damags to that protectiv- coat and without alterlng th- surface. ~n untr~ated sur~aces, ~uch a cleaner shall remove unwanted paint ~nd gra~$ti without da~age to t~e sur~ace.
Further, such a cleaner ha~ been found to ~e effective in cleaning and removing paint And finish from furniture.

In recent years ~h~re ~zs been an increased conc¢rn over t~e s~pidly growing proble~ of gra~iti, ~articularly in u~ban areas. In mod-rn t~mas, the term graffi~ h~s come to ac~uir~ a ~eaning whic~
dif~er~ cubstanti~lly from it'~ historical ~an~n~. ~he ~odern observer.
vlews gra~iti not as an art for~, but rathex, as a for~ of destruction and v~ndalism.

5h~ ~pplication o~ ~rar~iti and other unw~nted paint or coating-on a sus~ace ha~ beco~e ro~t prev21ent in institutions, suc~ as, ~ChoO15, public and private building~, auto~obll~s, ts~c~, train cars 1320~1~7 and rest rooms wh~ch are available to the pu~lic at large. Gra~Siti is even more problematic in open areas, such as, support walls and piers, b~idges, retaining walls, sound ~arriers, the exterior walls o~
~uildlngs, various structures in parXs, which incidentally were put there in the ~irst place to cosmetically impro~e the par~s and tha ll~e.
The vast majority Or such graffiti a~e color m~rkers having pigmen~ed dyes with f ast drying, pen-trating solvents and oil based paints including enamels, epoxies, lacquers and ureth~nes. The graffiti is usually applied by spray cans, and is applied to varlous types oS
sur~aces.~-`

The methods ~or t~e removal Oc ~raffiti and unwantsd paint, which for the most part a~e cost pro~i~itive, hav~ heretofore included sand~lasting, hydrosandin~ and hydroblastin~ the sur~aces on which the graffiti appesrC. These methods often involve a ubseguent re-painting o~ the sur~ace to restore its aesthetically pleasing appearance since sandblasting, ~ydrosandin~ and hydroblasting ma~e a surface porous and ~ough. Depending on the nature of the surface, such msthods could have a ~ot-ntially d~leterious erfect to the surface. For exa~ple, such methods can etch or ~core t~e sur~ace thereby creating a degree of porosity Wh~ch assists ln hold~ng later applied gra~fitl to the sur~ace, as w-ll as to Any a~ea in ¢lose proximity, ~nd sandblastlng will emit potentially c~rcinogen~c and slliceou~ part~cles lnto the air.

Another met~od which ha~ been used fDr removal o~ gra~fiti and 132~ 7 unwanted paint includes chemical treatment of the ~urface on which the graf~iti appears, such as acids and caustic solutions. This ~ethod has proven costly and unsuccessul. It has been ~ound that repetit~ve chemical cleanlng treatment quic~ly destroys the painted 6ur~ace th~reb~
necessitatlng frequent repainting. The application of such strons chemical cleaners also has a deleterious effect to the surroundtng environment and on the person applyinq the che~icals. Further, some o~
the chemicals are ~ow eithe~ banned as pollutants to th- environment or, perhaps, in the process o~ being banne~.

Perhaps the nost co~mon way o~ remo~ing gra~fitl is to repaln~
the surface and hope that the same individuals who had applied the original sraf~itl do not take the repainting as a new in~ltation to re~ine their ært skills. As can be appreciated, this approac~ is perhaps th- least ef~ective. It requires the use o~ a paint which is capable o~ covering the sraf~iti w~thout ble~d through o~ the underlying gra~iti.

U.S. ~atent 4,716,056, which issued on Decem~sr 29, 158? to Frank Fox znd Cassius W. Leys, the latter being the inventor of the present ~nvent~on, relates to a system for treatlng ~ surface and discusses tharein ~on-toxic cleaners which are particularly adaptable for removal of gra~fiti. A particularly pre~rred cleaner set forth in thi~ p~tent comprises; 28% toluene, 10% methyl ethyl ketone, 1~$ xylene, 2~ ethyl~n~ glycol n-butyl ether, 10% ~ethylene chloride, 15~ psopane, 15% i~opropanol, 2% ~ethanol and 5% o-dichlorobenzene. ~he drawbac~s of th~s Sormula is that th~ methylene chlor~de ~ifts the paint off in la~ge 13~0~17 scabs instead of emulsifying the paint into a watersoluble emulsion as in the present invention. Further, methylene chloride leaves a residue on the surface to be cleaned. Methylene chloride, furthermore, has been banned in some states due to its toxicity and has been classified as a hazardou~ chemical by the Occupational Safety and Health Administration (O.S.H.A.) and the Environmental Protection Agency (E.P.A.).

Other cleaners, such as AGP Wipe-Away by AGP
Systems, Inc., the assignee of the present application, remove graffiti, but do not act as effectively and with the very low volatile organic compounds (V.O.C.) as the cleaner of the present invention. Further, such cleaners are not water soluble, biodegradable and non-flammable.
*

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0115b/58-60 1 3 2 o ~

The present invention, in one broad aspect, provides a cleaner for removing graffiti, paint and other coatings from a surface, having N-methylpyrrolidone in an amount between about 2~
to about 40 percent by volume of the cleaner; propylene carbonate in an amount between about 20 to about 50 percent by volume of the cleaner; a hydroxy propyl cellulose thixotropic thickening agent in an effective amount; a dispersing ingredient which is selected from the group consisting of dipropylene glycol monomethyl ether acetate and dipropylene glycol methyl ether;
isocetyl alcohol, wherein the isocetyl alcohol and the dispersing ingredient are present in an amount which totals no more than 40 percent by volume of the cleaner; and a surfactant in an amount between about 1.6 to about 2.4 percent by volume of the cleaner.

The dispersing ingredient of the cleaner may be selected from the group consisting of diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl ether and diethylene glycol ethyl ether. The dispersing ingredient may be present in an amount of about 33.25 percent of the cleaner.

The N-methylpyrrolidone may be present in an amount of about 32.00 percent of the cleaner. The propylene carbonate may be present in an amount of about 31.8 percent of the cleaner.
The surfactant of the cleaner may be etho~ylated nonyl phenol.
The ethoxylated nonyl phenol may be present in an amount of 2.00 percent by weight of the cleaner.

A - 6a -132Q~t7 The thickening agent may be in an amount between about 0.50 to about 1.00 percent by volume of the cleaner.
Specifically, it may be about 0.75 percent by volume of said cleaner.

The cleaner may further have the ingredient amyl acetate. The amyl acetate may be present in an amount between about 0.10 to about 0.20 percent by volume of the cleaner.
Specifically, the amyl acetate may be present in an amount of about 0.20 percent by volume of the cleaner.

In a second broad aspect, the present invention provides a cleaner for removing graffiti, paint and other coatings from a surface, having N-methylpyrrolidone in an amount between about 20 to about 40 percent by volume; propylene carbonate in an amount between about 20 to about 50 percent by volume; a dispersing ingredient selected from the group consisting of dipropylene glycol monomethyl ether acetate and dipropylene glycol methyl ether; isocetyl alcohol, wherein the isocetyl alcohol and the dispersing ingredient total an amount up to about 40 percent by volume; ethoxylated nonyl phenol in an amount between about 1.6 to about 2.4 percent by volume; and hydroxy propyl cellulose thixotropic thickening agent in an amount between about 0.50 to about 1.00 percent by volume in the cleaner.

In a third broad aspect, the present invention provides a cleaner for removing graffiti, paint and other coatings from a A -6b-~320 ~ ~

surface, having, as a first active ingredient, N-methyl-pyrrolidone in an amount about 32.00 percent by volume; as a second active ingredient, propylene carbonate in an amount about 31.8 percent by volume; a dispersing ingredient selected from the group consisting of dipropylene glycol monomethyl ether acetate and dipropylene glycol methyl ether; isocetyl alcohol, wherein the isocetyl alcohol and the dispersing ingredient total an amount up to about 40 percent by volume; a hydroxy propyl cellulose thixotropic thickening agent in an amount about 0.75 percent by volume; surfactant etho~ylated nonyl phenol in an amount about 2.00 percent by volume; and amyl acetate in an amount about 0.20 percent by volume of the cleaner.

1 ~20 ~ 1 7 The cleaner of the present invention is particularly adapted for use on most surfaces generally susceptible to the application of graffiti or undesired paint including, for example, masonry, stone, metal, plaster board and treated and untreated wood. Such masonry surfaces may include cement, cement blocks, concrete, brick, mortar and the li~e, while such metal surfaces include aluminum and steel. The present cleaner is particularly adaptable for use on steel structures such as bridges, buildings, highway underpasses and overpasses, statues, walls and the like, and for removing paint coatings from equipment and machinery.

The cleaner basically comprises three active ingredients, a thickening agent and a surfactant. In particular, the cleaner composition includes:
N-methylpyrrolidone; propylene carbonate; an active ingredient selected from the group consisting of diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl ether, diethylene glycol ethyl ether and isocetyl alcohol;
and proprietary additives which include a hydroxy propyl cellulose thickening agent and a surfactant. More particularly, the composition comprises:
N-methylpyrrolidone in an amount between about 20 to about 40 percent by volume of the total composition; propylene carbonate in an amount between about 20 to about 50 percent by volume; hydro~y propyl cellulose thickening agent in an amount between about 0.5 to about 1.0 percent by volume; a surfactant, such as for ~' ' ~.

1320~ 17 T~, _c~l1 example ethoxylated nonyl phenol ~nown also as ~rit~ N-lO0 or x-loO, in an amo~nt betwsen about 1.6 to about 2.4 perce~t by volu~e; and the actlve in~redient selected ~rom the group consisting of diethylens glycol ~onoethyl ether acetate, diprDpylene ~lycol ~omomethyl ether aoetate, dipropylene glycol methyl ether, diethylene glycol ethyl ether and isocetyl alcohol in the remainlng amount by volume o~ the total composltion. The cleaner may also contain a propellant. The preferred propellant is carbon dioxide since it is non-rla~mable.

N-methylpyrrolidone, which is one active lngredient o~ the present cleaner composition, is a water soluble material. This partic~lar water soluble material has been ~ound to have excellent pa~nt remover prope~ties. N-me~hylpyr-olidone is sold under the tradc~ark M
~yrol by GAF.

It is believed that the N-methylpyrrolidone can be used in t~e cleaner composition in an amount between about 20 to about 40 percent, however it is pre~erred that the N-methylpyrrolidone be about 32.00 perc-nt o~ volume o~ the total cleaner co~position. It ha~ been ~o~nd that ~bove 40 percent the N-~e~hylpyr~olidone i8 much too expensive to use and below 20 percent it does not prov~de the f~vorabl- results achieved witnin th- range.

~ ropyl~ne carbonate i5 th~ second ~ctlve 1n~reaient. ~t is availa~le through Arco Chemieal~. ~ropyle~e c~rbonate should be pro~ided in the clean-r co~position in an ~mount between about 20 to about ~0 percent ~y volume of the tot~l compo~ition. Below 20 percent _g_ 1320~ 1 7 and above 50 percent the propylene carbonate is not as erSectlve as ln the reoited range because it acts too slow~y. It is p~eferred that the propylene carbonate ~e present in an amount about 31.8 percent by volu~e of the total cleaner composition.

It is believed that the above two sp-c~ic active in~r~d~ents ~re needed for the present cleaner co~position to ba ersective. It is also believed that to achieve optimu~ results a third acti~e ingredlent is n-eded. Flve chemicals or materials have been found to work effectively as the thixd aetive ingr~dient. These ~ive ~aterials comprise rour glycols and isocetyl alcohol.

One of the glycol materials is diethylene qlycol ~ono~ethyl ether acetate. ~his ~aterial readily d~sperses both t~e ~-methylpyrrolidone and the propylene car~onate in t~e clea~er compos~tion. A econd such material ls dipropylene glycol monomethyl ether acetate.

When either diethylene glycol monomet~yl ether acetate ~r d~propylene glycol ~onomethyl ether acetate is used in the cleaner co~positlon, the cleaner is ~xtremely ef~eetlve in removing grafflti ~rom any sur~sce. Further, these two active ~ngrsdlents hav- the advantage o~ having a very high boil~hg point and an exceeding low -evaporation rat~. This is signl~icant since with these propertles the resultlng cle~ner ~eeomes a very low volatile organ~c compound (V.O.C.) cle~nQr which ~s wQll below pr~sently acc-ptablOE ~.O.C. regulatory l-vels.

~320 ~17 ~ he other two glycol ~aterials are dipropylene glycol ~ethyl ether and diethylene glycol ethyl ether. Dlpropylene glycol methyl ether and diethylene ~lycol ethyl ether are ba6ically the same che~icals as diethylene glycol monomethyl ether acetate and dipropylene glycol monomethyl ether acetate. However, the ~orm-r two have a raster evaporative rate than the latter two ~o in ~rfect they provlde much higher V.O.C. factors, whi~h are undesirable, in ~he prQs-nè cleaner composition. ~urther, dipropylene ~lycol methyl ether and dlethylene glycol ethyl ~ther ~ach has a ~oiling ~oint lower than diethylene glyco monomethyl ether acetate and dipropylene glycol ~onomethyl ~ther acetaL~
again contri~uting to undesired V.o.c. factors in the resultant cleaner.

Thus, the use of diethylene glycol monomethyl eher acetate and dipropylene glycol monomethyl ethe~ acetate are p~eferr~d sinca they ars more stable, i.e. they have a slower evaporation rate and, th-refore, ~re ~ore desirable environmentally. ~owever, dipropylene glycol methyl ther and di~thylene glycol ~thy~ ther will worX ef~ectively ln t~s clean~r foroulas of the present ~n~ention.

I60CQtY1 ~lcohol, the fi~th material, works with ~he two above specific ~ctlve ~ngredients. It, ~owever, does not work as quickly as diethylene glycol monomethyl ether 2cetate or dipropylene ~lycol mo~o~ethyl ether ~cetate i~ disper~ins the two oth~r activ- inqrodients.
~ccor~ingly, It ~s noe as desirabl- as dlethylene ~lycol monomethyl t~er acetate and dipropyl~ne glycol mono~ee~yl other aceeate.

1320~17 The third act~ve ingredi~nt should be used in the cleaner composition in an amount to bring the total cleaner composition to one hundred percent by ~olu~e. ~owever, the material ~hould b~ no ~ore than about 35 to about 40 perc~nt by volume of the total cleaner composition because abo~e 40 percent the individual ingredients reduce the e~fectiveness of the other active ih~redients and can att~ck t~e substrate in certain circumstances.

~ ertain proprietary ~dditives must ~e include~ in the cleaner composition. ~hQse additlv~s are non-toxic materials. Specifical~y, a hydroxy propyl cellulose thixotropic thickening agent and a ~urfactant ~re two proprietary additlves that are needed to provid~ pre~erred results. It is preerred, although not n-cessary, that th~ cleaner co~position contain a third proprietary additive in order to abate odor.

Th- thickenlng ~gent is needed to in~ure that the cleaner is Xept on the surface to be treated when th~ surface is ~lopinq or vertical or the cleaner is applied to the underside of a horizontal surface. B2sically, th- thickening agent ma~es cert~in that the s~fac-retains the cl-aner.

A ~he preferx-d hydroxy propyl cellulose thixotroplc thlck~ning zgent, is co~monly sold under the name ~lucel ~ and is ~ade available Py ~qua~one Company. ~his particul~r thicke~in~ ~gent is prefe~red b-caus- it i~ comp~tible with both activa ~ngred~cnts. sp-ci~cally, it has found to ~ave exc411ent solubility with both of the actlv-ingrediants.

k 1320-:~17 Xlucel H should be present in an amount ~etween about 0.5 to a~out 1.O percent by volume of the total cleaner composition. In the pre~erred cleaner compositlon, it hould be presént ln an amcunt o~
about 0.75 percent ~y volu~ of the cleaner composition.

The ~econ~ proprietary additive is a surfactant. While a ~pecific surfactant is not needed, ethoxylated nonyl phenol, which is also ~nown as Tri~- n ~-lOo or x-100, is prefcrred. ~he amount of ethoxylated nonyl phenol is between about 1.6 to about 2.4 percent by volume o~ the total cleaner composition. ~owe~er, it should be present in an amount a~out 2.00 ~ercent by volume in the pre~err~d clezner composition. It has b~en found that the sur~actant wlll 105e or diminish its water affinity properties should the amount o~ the sur~actant be below 1.~ ~ercent, while the surfactan~ will lose or diminish its so~vent a~inity should th- a~o~nt oS tbe sur~actan_ be abova 2.4 percent.

While the third propriet~ry additive i5 not needed for the cleaner to treat c~Sectively the ~urface, it is needed to abate the otherwi~Q ~trong odors o~ the cleaner. The pru~err-d t~ird proprietary add~tive is amyl acetate. Amyl acetate ls Al50 known ~s ~anana oil, and i5 pre~ent in t~e pr~fer~-d cleaner composition in an a~ount a~out o.20 ~ercent by volu~e o~ the total composition.

When small amounts of sur~ce area ~re to be cleaned, th~ tot~l cl~aner composition is o~ten bcst utilized by d~spersing same in a ~- ~r6~ k ~320~7 spray. Ac-ordin~ly, a propellant is n~ed~d.

It has been fo~nd that carbon dloxide is t~e preferr~d propellant since it is a no~-fla~mable propellant. To the above cleane_ composition, the propellant is added in a~ount between about two (2) to a~out four (4) percent so that t~ p~opellant constitutes about two (2) to about ~our (4) percen~ and the total cleaner composition i5 ninety-six ~6) to a~out ninety-elght (98) percent of the resultant ~pray co~position.

It will be ~ppreciated that the a~ount oS each co~ponent of the cleaner will v ry withln the range set forth above dependlng upon the particular application. In a preferred e~odiment, t~e cleaner, wh~ch is particularly adapta~le for re~oval oS srafSiti typically applied by various ~pray paints, contains the pref erred ingre~ients s~t ~orth a~ove.

The cleaner compo~ition has a vapor pre~sure of betwe~n about 85 to about 100 psig at seventy degrees Fahrcnheit. Further, the ~peciric gra~ity of the cleaner is 1.060. Th~ cleaner is water ~olubl~, has a pale yellow app~arance and has 2 so~ewhat fruity ~ragrance. ~oreover, the cl~aner is ~on-~la~able. Due to t~e cleane~'~ wat~r solubllity, it can b- r~ns-d or w~shed ofS wit~ water.

It has been Sound that t~e cleaner has a ~.O.C. ratlng well b~low 0.1 ~s ~asured by pr~sent ~.S. Government E.P.A. and O.S.X.A.
~t~ndard~. Accordingly, this cleaner is exe~pt ~rom ~xisting -~4-1~20~17 regulations regarding toxicity and V.o.C. levels.

After application, the cleaner is perm~tt~d to react for a period ~ ~rom one (1) to about rive (5) ~inutes on grafflti protecLive coated sur~aces and a~out thirty t30) to about forty-five (45) ~lnutes on untreated gra~fi~i bearing surfaces.

The cleaner is applied in the typical fa~hion ~y application onto tha graff~ti on th- surf~oe using a roller, a brush or a ~pray.
Aerosol spraying, however, is t~e pre~erred ~ethod o~ application for small surfac- areas to be cleaned. When applied by aerosol ~pray, the cleaner initially prov~des a ~Dam on the ~u-face to b- cle~ned.

With any type application, t~e cleane~ should be le~t on the surface ~or a ~inimu~ fro~ about one (1) to about flve (5) minutes to a maximum o~ about one (1) hour. The cleaner 2nd th~ underlying ~afflti i5 then easily removed from non-porous sur~aces. It has been found t.~at the cleaner is cffeotive in removing ~ost, if not all, typ-s o~ graf~itl w~out attac~ing ~n underlying surface. The eleaner has been ~ound particularly e~ectiv- on non-porous surfaces, such 25 aluminum, steel, treated wood and certain macon~te~type co~positions.

T~e cleaner i5 applie~ to the surf~ce at a thicXn-ss which is detex~ined by the a~ount and the numb~r o~ coating~ o~ ~ra~iti on the su~r ce or substrate to bs clsaned. T~e nu~ber ~ coats o~ the cleaner depends on the age of the grafflti And the type o~ the su~-~trate under t~e graf~iti.

1320~1 7 The pre6ent cleaner removes grafSiti from certaln deQired ~rotectivs coated or painted surfaces without damage to that proteclive coat and wlthout altering the surface Further, the cleaner shall remove unwanted paint and ~raffiti rom an untreated sur~ace without da~age t~ the surface Basically, the cleaner acts to remove al' gra~Siti and all ~on-protective coatings frou a surSace, although f~r non-protective coated sur~aces, usp-cially when the cubstrate is porous, a water pressure washer uaybe n--ded to rl ush out ~mul~ d p~int ~nd excess cleaner When used to clean or remove finish ~ro~ furniture, the composltion is applied as provided a~ove The cle~ner e~ulsifies, and thus removes, the ~inish ~and unwanted vanis~, stains and paint~ Sron the furniture The fuxniture that can be treated is wocd, metal and maso~ry furniture The cleaner has not, howe~ex, been ~ound erSectlve for plastics ~nd ~abric The ~ol~owing exa~ples serve to illustrate certain preferred forms of the cle~ner co~position oS the present invention 132~ 7 EX~MPLE 1 n~redient ~mount (% bv weicht) Tv~e o~ in~redler.t ~-methylpyrroll~one 20 to 40 active Propylene car~onate 20 to 50 activs Xlucel ~ ~ 0.50 to 1.00 th~cXening age~t Ethoxylated nonyl phenol 1.60 to 2.40 ~ur2actant Isoc~tyl alcohol q.s. ac~lve Other 0.20 ~dditivs In~redlent Amount (% bv wei~ht) TvDe of Tn~redient N-methylpyrrolidone 32.0 ac~ive ~opylene carbonate 31.8 active one o~ the ~our speCiric ~lycols 33.25 ~rti~e ~lucel H~ O.75 ~hlck~ning agent Ethoxylated nonyl phenol 2.0 surfactant Oth~r 0~20 additi~e ~ he additive(s) ln both examples pre~erably is amyl acetate which is used to ab~to odor.

Having thus de~cribed t~e i~vention with particular re~ersnce to the pre~erred ~orm~ thereof, i~ will ~e obvlous t~at various c~anges and * ~ ~r6~ rk ~320 ~

modif ications ~ay be ~nade t~erein without departing Srom the spirit and SCOpB O~ th~ invention as de~ined by th~ appended cla~ns.

Claims

1. A cleaner for removing graffiti, paint and other coatings from a surface, said cleaner comprising:
(a) N-methylpyrrolidone in an amount between about 20 to about 40 percent by volume of said cleaner;
(b) propylene carbonate in an amount between about 20 to about 50 percent by volume of said cleaner;
(c) a hydroxy propyl cellulose thixotropic thickening agent in an effective amount;
(d) a dispersing ingredient which is selected from the group consisting of dipropylene glycol monomethyl ether acetate and dipropylene glycol methyl ether;
(e) isocetyl alcohol, wherein said isocetyl alcohol and said dispersing ingredient are present in an amount which totals no more than 40 percent by volume of said cleaner; and (f) a surfactant in an amount between about 1.6 to about 2.4 percent by volume of said cleaner.

2. The cleaner of claim 1, wherein said dispersing ingredient is an ingredient selected from the group consisting of diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol methyl ether and diethylene glycol ethyl ether.

3. The cleaner of claim 1, wherein said N-methylpyrrolidone is in an amount of about 32.00 percent of said cleaner.

4. The cleaner of claim 1, wherein said dispersing ingredient is present in an amount of about 33.25 percent of said cleaner.

5. The cleaner of claim 1, wherein said propylene carbonate is in an amount of about 31.8 percent of said cleaner.

6. The cleaner of claim 1, wherein said surfactant is ethoxylated nonyl phenol.

7. The cleaner of claim 6, wherein said ethoxylated nonyl phenol is in an amount of 2.00 percent by weight of said cleaner.

8. The cleaner of claim 1, wherein said thickening agent is in an amount between about 0.50 to about 1.00 percent by volume of said cleaner.

9. The cleaner of claim 1, wherein said thickening agent is in an amount of about 0.75 percent by volume of said cleaner.

10. The cleaner of claim 1, further comprising amyl acetate.

11. The cleaner of claim 10, wherein said amyl acetate is in an amount between about 0.10 to about 0.20 percent by volume of said cleaner.

12. The cleaner of claim 10, wherein said amyl acetate is in an amount of about 0.20 percent by volume of said cleaner.

13. A cleaner for removing graffiti, paint and other coatings from a surface, said cleaner comprising:
(a) N-methylpyrrolidone in an amount between about 20 to about 40 percent by volume;
(b) propylene carbonate in an amount between about 20 to about 50 percent by volume;
(c) a dispersing ingredient selected from the group consisting of dipropylene glycol monomethyl ether acetate and dipropylene glycol methyl ether;
(d) isocetyl alcohol, wherein said isocetyl alcohol and said dispersing ingredient total an amount up to about 40 percent by volume;
(e) ethoxylated nonyl phenol in an amount between about 1.6 to about 2.4 percent by volume; and (f) hydroxy propyl cellulose thixotropic thickening agent in an amount between about 0.50 to about 1.00 percent by volume in said cleaner.

14. A cleaner for removing graffiti, paint and other coatings from a surface, said cleaner comprising:
(a) a first active ingredient, said first active ingredient being N-methylpyrrolidone in an amount about 32.00 percent by volume;
(b) a second active ingredient, said second active ingredient being propylene carbonate in an amount about 31.8 percent by volume;
(c) a dispersing ingredient selected from the group consisting of dipropylene glycol monomethyl ether acetate and dipropylene glycol methyl ether;
(d) isocetyl alcohol, wherein said isocetyl alcohol and said dispersing ingredient total an amount up to about 40 percent by volume;
(e) a hydroxy propyl cellulose thixotropic thickening agent in an amount about 0.75 percent by volume;
(f) a surfactant, said surfactant being ethoxylated nonyl phenol in an amount about 2.00 percent by volume; and (g) amyl acetate in an amount about 0.20 percent by volume of said cleaner.