GB2558446A

GB2558446A - Environmentally acceptable spray gun cleaning apparatus fluid and method

Info

Publication number: GB2558446A
Application number: GB1804410.7A
Authority: GB
Inventors: James Plant Anthony
Original assignee: Ui Equipment Ltd
Current assignee: Ui Equipment Ltd
Priority date: 2016-09-09
Filing date: 2016-09-09
Publication date: 2018-07-11
Anticipated expiration: 2036-09-09
Also published as: GB2553772B; GB2553772A; GB2558446B; GB201804410D0; GB201615354D0

Abstract

A composition for cleaning paint, such as automotive paint, from a spray gun is provided. The composition is an aqueous cleaning-fluid comprising at least 5% by weight of an amphiphillic solvent. The solvent may be N, N-dimethyl 9-decenamide. The composition may also comprise an antifoaming agent such as poly-dimethyl siloxane and/or and anticorrosion agent such as an alkyl-ethoxylate.

Description

(71) Applicant(s):

UI Equipment Limited

Lady Bay Road, West Bridgford, NOTTINGHAM, Nottinghamshire, NG2 5BJ, United Kingdom (72) Inventor(s):

Anthony James Plant (51) INT CL:

B05B 15/55 (2018.01) C11D 1/00 (2006.01) (56) Documents Cited:

JP 2008266649 A JP 2005272683 A

US 4770713 A US 20050009718 A1 (SURFACHEM) Catalogue entry for N, N-dimethyl 9decenamide. Known as a cleaning agent for paint removal.

(58) Field of Search:

INT CL B05B, C11D Other: EPODOC, WPI (74) Agent and/or Address for Service:

Patent Outsourcing Limited 1 King Street, BAKEWELL, Derbyshire, DE45 1DZ, United Kingdom (54) Title of the Invention: Environmentally acceptable spray gun cleaning apparatus fluid and method Abstract Title: Aqueous spray gun cleaning-fluid (57) A composition for cleaning paint, such as automotive paint, from a spray gun is provided. The composition is an aqueous cleaning-fluid comprising at least 5% by weight of an amphiphillic solvent. The solvent may be N, Ndimethyl 9-decenamide. The composition may also comprise an antifoaming agent such as poly-dimethyl siloxane and/or and anticorrosion agent such as an alkyl-ethoxylate.

The references to the drawings in the printed specification are to be treated as omitted under Section 15(5) or (6) of the Patents Act 1977.

ENVIRONMENTALLY ACCEPTABLE SPRAY GUN CLEANING APPARATUS, FLUID AND METHOD

The present invention relates to spray gun cleaning apparatus, fluids and methods and particularly to spray gun cleaning apparatus, fluids and methods which mitigate harm to the environment.

Background

Spray painting is a method in which a device sprays a coating through the air onto a surface. The coating may be, for example, paint, ink, or varnish, or any other similar coating.

Spray guns are typically used for covering surfaces with an even coat of liquid coating and can be automated or hand-held, often having interchangeable heads to allow for different spray patterns. In use, the liquid coating is sprayed onto the surface using a pressurised gas, usually air.

Known apparatus and methods for cleaning spray guns use hydrocarbon-based solvents such as acetone, xylene and toluene or a combination of such solvents, which are commonly known as “gun wash” or “standard thinners”. However, hydrocarbon solvents are generally used for cleaning solvent-based paints from spray guns, and water-based cleaning surfactants are used for cleaning the newer water-based paints.

The use of hydrocarbon-based solvents can be problematic in that use can cause damage to the environment through Volatile Organic Compounds (VOC) emissions. Hydrocarbon solvents also present a risk of inhalation by humans and animals, with associated health and safety issues, as well as risks associated with fire and disposal. Additionally, the moral and legal requirements of managing these risks give rise to a cost for industry.

Therefore, there is a need in the industry for there to be means to at least substantially mitigate the disadvantages of the known apparatus and methods for cleaning spray guns.

There is also a need in the industry for there to be means for providing biodegradable sustainably-sourced water-based surfactants, apparatus and methods suitable for l

cleaning both organic solvent and water-based paints from spray guns and associated equipment.

Summary

According to a first aspect of the present invention, there is provided a spray gun cleaning apparatus, the apparatus comprising: a reservoir for storing an aqueous cleaning-fluid; a cleaning-fluid conduit operable to deliver said aqueous cleaning-fluid under pressure from the reservoir to at least one cleaning-fluid outlet, the conduit comprising: a first filter operable to filter particulate matter in the range of 10 to 50 pm; a pump operable to pump the aqueous cleaning-fluid at a pressure of greater than 20 psi; a second filter operable to filter particulate matter greater than 5pm; and a third filter of activated carbon for sequestering contaminants.

The apparatus may further comprise a cleaning chamber for receiving a spray gun to be cleaned. The cleaning chamber comprises the at least one cleaning-fluid outlet suitably disposed for cleaning a said spray gun. The cleaning chamber advantageously also comprises a base having one or more apertures and means for containing used cleaningfluid and guiding it towards an outlet conduit.

The means for containing used fluid comprises debris-separating means, which is advantageously in the form of a weir having a raised drainage outlet in fluid communication with the outlet conduit.

The, or each, cleaning outlet may comprise an outlet head for providing a plurality of jets of cleaning-fluid.

The apparatus advantageously comprises a plurality of cleaning outlets, wherein one of said plurality of outlets is advantageously operable to attach to a paint inlet port of a paint spray gun to cause cleaning-fluid to flow inside the said spray gun.

The apparatus comprises a plurality of cleaning outlets, wherein at least one of the plurality of cleaning outlets is suitably disposed to clean one or more spray gun accessories.

The apparatus is advantageously operable to receive a pressurised air supply and utilise the pressurised air supply for one or more of: providing motive power to the pump;

operating a Venturi extractor headspace from the cleaning chamber; back flowing through said conduit for the purposes of cleaning the conduit; determining blockage through identifying back pressure exceeding a predetermined threshold; supplying air to the said spray gun when the said spray gun is a pneumatic spray gun such as to prevent soil ingress into the pneumatic conduit of the spray gun.

The pressurised air supply may be in the range 10 to 100 psi.

The apparatus advantageously further comprises a pressure-actuated indicator disposed between the pump and the first filter or between the pump and the second filter or between the pump and the activated carbon filter and operable to actuate when a pressure threshold has been exceeded so as to indicate when the first or second filter capacity has been reached.

The pump is advantageously configured to operate at a flow rate of between 10 and 20 litres per minute and at a pressure of greater than 30psi.

The activated carbon filter is advantageously a monolithic carbon block.

The outlet conduit is advantageously configured to return the used cleaning-fluid to the reservoir.

According to the second aspect of the present invention, there is provided an aqueous cleaning-fluid for removal of aqueous- and non-aqueous based paint residues from a spray gun being cleaned, the aqueous cleaning-fluid comprising at least 5% by weight of an amphiphilic solvent.

The problem addressed by the aqueous cleaning-fluid of the present invention is to provide a composition suitable for cleaning by removal of aqueous and non-aqueous based paint residues in, for example, cleaning a spray gun and related equipment. The present invention in its various aspects is preferably used for removing automotive paint residues, whether used at an original manufacturer or as part of repair, such as accident repair. Particularly with accident repair a large number of different paint types need to be cleaned from equipment. Whilst this could optimally be done by having a different cleaning-fluid for every type of paint this is unnecessarily complicated and with limited workshop space not practical. Even then the new generation of reactive, or two pack or two-component, paints which chemically change when admixed so as to provide less soluble materials upon reaction between their separate precursor components mean that simple solubility is not necessarily a route to removing dried or in this case cured paint residues.

Furthermore, cleaning stations may be provided, such as the apparatus described in the present invention. These are relatively high value pieces of equipment and take up space in the workshop. It is therefore particularly advantageous to provide only one, universal, cleaning-fluid for use with such equipment that can clean the whole range of automotive type paints. This is particularly so as changing cleaning-fluids in a single piece of equipment is unduly complex and time-consuming and duplicating equipment for different paint types is not practical particularly in smaller premises. The present invention addresses this problem of providing a wide spectrum cleaning-fluid, suitable for removing aqueous, non-aqueous and reactive paints and does so by means of using an aqueousbased fluid comprising an amphiphilic solvent. Amphiphilic solvents are thought to be effective because the amphiphilic nature provides a surfactant type effect to both address aqueous and non-aqueous paints whilst the solvent serves to both dissolve some paint components and disrupt the polymeric structure of cured reactive paints.

The cleaning-fluid of the present invention preferably selects the amphiphilic solvent from one or more of N, N dialkyl Cs to C10 amide, N, N dimethyl lactamide, 2 ethyl hexyl lactate, gamma butyro lactone, tetrahydrofurfuryl alcohol, glyceryl carbonate, methyl caprylate caprate, alkyl amide and cationic derivatives thereof. These amphiphilic solvents have been found to be effective for removal of a range of dried aqueous and non-aqueous based automotive paints from equipment. They have also been found to have the additional advantage of removing grease. Whilst the latter may not be thought of as being particularly relevant it is not unknown in an automotive workshop to use paint cleaningfluids for other purposes, such as degreasing wrenches, spanners and other repair tools. Lithium based greases widely used in automotive lubrication are particularly difficult to remove using conventional detergents, whereas the composition of the present invention readily removes such contaminants without resorting to high VOC solvents. The amphiphilic solvents are also less volatile than normal automotive paint organic solvents such as methanol, acetone, isopropanol, butanol, xylene and toluene (such as are typically provided in a blend as “gun wash” or “standard thinners”). This reduces environmental exposure, such as to a user of the fluid and also reduces and effectively eliminates flammability-related safety problems.

The amphiphilic solvent materials are advantageous in that they are solvents, i.e. they are normally liquid at room temperature and are capable of mixing (i.e. not separating) with both water and ‘oils’ (such as xylene and toluene and other non-aqueous automotive paint solvents). Being amphiphilic they also have a surfactant nature which disperses removed paint particles and pigment particles in the fluid so they may be removed, and preferably used in combination with the apparatus of the present invention which filters off such particles.

The cleaning-fluid of the present invention preferably uses an amphiphilic solvent which is one or more of N, N dialkyl Cs to C10 amide or N, N dimethyl lactamide. These are particularly effective in that they appear to avoid the clumping of removed automotive paint. Particularly when relatively new equipment is being cleaned which has a relatively low surface area then it is possible for relatively large pieces of paint to peel off during the cleaning process, particularly a pressure cleaning process such as provided by the apparatus of the present invention. These large pieces of paint can tend to come together and block up apertures, either in the equipment being cleaned or in apparatus used for recirculating the cleaning-fluid. Hence, these particular amphiphilic solvents are preferred.

In the present invention the most preferred amphiphilic solvent is N, N-dimethyl 9decenamide. This has been found to give the best overall cleaning performance with a range of automotive paint residues, aqueous, non-aqueous, cured reactive as well as oil and grease contamination.

The aqueous cleaning-fluid of the present invention preferably has the amphiphilic solvent present at a level of from 5% to 35% by weight of the fluid. This range of composition enables effective removal of water-based paints even at the higher levels of the solvent and removal of non-aqueous based paints at the lowest level. However, at the extremes of these ranges paint removal effectiveness is biased towards one type of paint. For effective universal paint removal then in the present invention the amphiphilic solvent is more preferably present at a level of from 10 to 20% by weight of the fluid. This level appears to give good general overall performance.

More preferably the aqueous cleaning-fluid of the present invention may comprise from 64% to 95% water. The addition of more than token amounts of organic solvents can reduce the suspension effectiveness of removed paint, i.e. removed paint can clump and sediment more easily and it is the combination of amphiphilic solvent and water which provides the most effective balance of properties of the present invention. The present invention preferably comprises no more than 5% of other components. An overall preferred composition of the present invention therefore comprises from 5 to 35% by weight of the amphiphilic solvent, up to 5% auxiliary components such as anti-foams and anticorrosion agents with the residue being water. This composition range is also effective in that it remains liquid under normal workshop conditions, such as a winter close down condition where temperatures of down to -10°C may occur. This composition is therefore also freeze resistant. Similarly, the compositions of the cleaning-fluid of the present invention even if heated to near boiling point of the water do not produce significant levels of volatile components, such as may give rise to a flammability risk or to unduly toxic exposure. This is relevant in the workshop environment where cleaning-fluid may be spilt onto hot components (such as space heaters used in the winter or even a hot exhaust of a vehicle).

Whilst the primary requirement of the aqueous cleaning-fluid of the present invention is that it is effective in removing paint residues, particularly automotive paint residues and more particularly automotive paint residues from spray equipment it is also important that the composition is environmentally acceptable. This is particularly significant due to the disposal requirements for used product which will comprise both the cleaning-fluid, particularly xylene-based fluids, and paint residues. The compositions of the present invention are far more environmentally benign than cleaning solvents normally used for non-aqueous and reactive automotive paints. Further, the aqueous cleaning-fluids of the present invention are biodegradable; water is of course environmentally neutral but the specific amphiphilic solvents described herein are all readily biodegradable. Furthermore, because cleaning-fluids of the present invention have a negligible VOC content they are more environmentally acceptable than present paint cleaning fluids. The aqueous cleaning-fluid may further comprise at least one of an antifoaming agent and an anticorrosion agent. The antifoaming agent may comprise Poly-dimethylsiloxane. The anticorrosion agent may comprise an alkyl-ethoxylate.

The aqueous cleaning-fluid of the present invention preferably has a pH in the range 6 to 8. Keeping the pH close to neutral also ensures no damage is caused to the spray guns, for example by corrosion, amine-based solvents are therefore less preferred and preferably excluded from cleaning-fluids of the present invention. This is provided by the preferred amphiphilic solvents and in particular, N, N dialkyl Cs to Cw amide (even more preferably N, N-dimethyl 9-decenamide) or N, N dimethyl lactamide. Whilst high alkalinity or acidity can help paint removal this reduces the safety of the composition particularly for use in the relatively uncontrolled workspace of an automotive repair centre.

According to a third aspect of the present invention, there is provided a system comprising the apparatus according to the first aspect of the present invention in combination with an aqueous cleaning-fluid according to the second aspect of the present invention.

According to a fourth aspect of the present invention, there is provided a method of cleaning a spray gun using the system according to the third aspect of the present invention, the method comprising: providing the cleaning-fluid according to the second aspect of the present invention and passing it through the apparatus according to the first aspect of the present invention.

Description

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 is a schematic drawing of the apparatus according to the present invention.

Referring to Figure 1, apparatus 10, according to the present invention. This comprises a reservoir 12 for storing an aqueous cleaning-fluid 14, and a cleaning-fluid cleaning conduit 16 operable to deliver the cleaning-fluid 14 under pressure from the reservoir 12 to one or more cleaning outlets 18a-18c.

The cleaning-fluid conduit 16, such as a comprising tube, comprises a first filter 20 operable to filter particulate matter in the range of 10 to 50 pm, a pump 22 operable to pump the aqueous cleaning-fluid at a pressure greater than 30 psi, a second filter 24 operable to filter particulate matter greater than around 5pm, and an activated carbon filter 26 for sequestering contaminants.

The pump 22 is preferably configured to provide a flow rate of between 10 and 20 litres per minute and at a pressure greater than 10psi and delivers the cleaning-fluid 14 from the reservoir 12 through a dip stick conduit 27 disposed in the reservoir 12

The first filter 20 is a 10 to 50pm mesh filter and is disposed in the cleaning conduit 16 between the reservoir 12 and the pump 22. The second filter 24 is a 1 to 10pm two-stage resin bonded woven filter and is disposed in the cleaning conduit 16 between the pump and the third filter 26. The third filter 26 is a 1 to 5pm activated carbon filter between 10 and 20 inches (25 and 51 cm) in size which is preferably of a monolithic block form. The use of a monolithic block is particularly advantageous in that it excludes routes for other than sub-micron particulate material from passing the filter. This excluded material, particularly when cleaning-fluid is passed through the air inlet of a spray gun being cleaned is capable of blocking the fine orifices used to generate the aerosol spray when such spray guns are used. The monolithic block therefore performs a dual function of sequestering by adsorption dissolved organic materials and contaminants as well as removing by filtration material not previously captured by early filtration stages.

The reservoir 12 may be a drum or similar container, preferably having a sealed cap 28.

The, or each, cleaning outlet 18a-18c has an outlet head 19a-19c, operable to provide a plurality of jets of cleaning-fluid under pressure from each cleaning outlet, 18a-18c.

The cleaning conduit 16 is configured to deliver the cleaning-fluid 14, via the, or each, cleaning outlet 18a-18c into a cleaning chamber 30.

The cleaning chamber 30 comprises a spray gun cradle 32, a filter base 34, means for containing used fluid which may be in the form of a collection tray 35 and one or more chamber outlet 38. The spray gun cradle 32 is configured and operable for receiving and supporting a spray gun 40 during a cleaning process. The cleaning chamber further comprises a cleaning-fluid distributor 39 which is disposed to receive the cleaning-fluid from the cleaning conduit 16 and distribute the cleaning-fluid through the cleaning outputs, 18a-18c for cleaning the spray gun 40. In addition to the cleaning outputs 18a18c, a further internal cleaning output 42 may be attached to a paint input port 43 of the spray gun 40 such that cleaning-fluid can flow through the inside of the spray gun 40.

In an alternative embodiment, the cleaning-fluid distributor 39 may be operable to spin about its own axis, such as by means of force generated by angled outputs to give torsion, and thereby rotate the cleaning outputs, 18a-18c, to provide greater coverage of the cleaning-fluid over the surface of the spray gun 40.

The cleaning chamber 30 may additionally comprise an accessory cleaning output 44 having an outlet head 46 operable to provide a plurality of jets of cleaning-fluid. The accessory cleaning head is suitably disposed in the cleaning chamber 30 to clean spray gun accessories such as, for example, a paint pot 48.

The filter base 34, ofthe cleaning chamber 30, is a 50 to 100pm gauze filter. The collection tray 35 is disposed to underlie the filter base 34 and collect the used cleaningfluid. The chamber outlet 38 is disposed and operable to drain the collection tray of the used cleaning-fluid and return the cleaning-fluid through the sealed cap 28 to the reservoir 12, for recirculating.

In a preferred embodiment, the collection tray 35 further comprises a weir having a raised fluid outlet barrier 36 such that, in use, a depth of used cleaning fluid is maintained which functions to collect paint particles as they sink to the bottom. This is particularly beneficial as it greatly increases the longevity of filter 20 in normal use.

The cleaning chamber 30 may additionally have a Venturi extractor 50 for venting the chamber of gases.

The apparatus 10 may additionally have a pressurized air supply (not shown) which may be utilized to provide motive power to the pump 22 and/or the Venturi extractor 50. The pressurized air supply may additionally be utilized for: providing back flowing through the cleaning conduit 16 for the purposes of cleaning the conduit; determining blockage in the cleaning conduit 16 by identifying back pressure exceeding a predetermined threshold; and/or supplying air to a spray gun 40 via the spray gun output nozzle 52 to prevent soil ingress into the pneumatic conduit of the spray gun 40.

The pressurised air supply may be in the range 10 to 100 psi.

The cleaning-fluid 14 is an aqueous fluid which comprises an amphiphilic solvent as hereinbefore described. The cleaning-fluid 14 further may additionally comprise an antifoaming agent and an anti-corrosion agent. If used, the anti-foaming agent may comprise poly-dimethylsiloxane and the anti-corrosion agent may comprise alkyl-ethoxylate.

In using this cleaning-fluid with the apparatus zero VOC emission can be achieved with the preferred amphiphilic solvents ofthe present invention in particular those having a low vapour pressure below 0.1 mmHg at 20° and a boiling point above 216°C.

Referring to Figure 1, a method for cleaning a spray gun 40 comprises providing a system comprising the apparatus 10 and cleaning-fluid 14. The method comprises: actuating the pump 22 to pump the cleaning-fluid 14 from the reservoir 12 through the dip stick conduit and through the first filter 20. The fluid is pumped at a flow rate of between 10 and 20 litres per minute at a pressure greater than 10psi, preferably 30 psi.

Passing the cleaning-fluid through the first filter 20 enables removal of particles of around 50pm in size which are potentially harmful to the pump. Therefore, positioning of the first filter 20 upstream of the pump 22 provides protection for the pump itself.

Having passed through the first filter 20 and the pump 22, the cleaning-fluid then flows through the second filter 24, which provides a two stage filtering for removing particles of 1 to 10pm in size. The two-stage filter cartridge maximises particle removal and service life of the cartridge. It also contributes to increasing the usable lifetime of the cleaning fluid by up to 75%, improves cleaning performance of the apparatus and system and reduces maintenance requirements. It is of silicon-free construction to prevent any contamination problems with the different spray guns which may be cleaned.

Having passed through the second filter 24, the fluid then flows through the third filter 26, which is a 1 to 5pm activated carbon filter. The third filter 26 acts to remove and absorb hydrocarbons from the cleaning-fluid 14. These are the hydrocarbons which were from the paint removed from the spray gun in the previous cycle of cleaning. The third filter 26 is operable to remove between 360 and 720 grams of contamination. This may account for enabling 99% removal of hydrocarbons. By removing the hydrocarbons, the VOC and COD of the fluid and the hazardous contamination, such as residual paint solvent from non-aqueous paint residues, is reduced which keeps the cleaning-fluid biodegradable and environmentally acceptable and useable for recirculation/re-use as a cleaning-fluid.

Having flowed through the third filter 26, the cleaning-fluid is sufficiently clean to be recycled into the cleaning chamber 30 via route A of the cleaning conduit, or disposed of via route B with limited environmental impact, limited risk of human and animal inhalation and health and safety, and limited risk associated with fire and disposal of the waste cleaning-fluid. In addition to mitigating these risks, the time and monetary cost and moral and legal requirements of managing these risks are removed or at least substantially mitigated.

If the cleaning-fluid is to be used for further cycles of cleaning, the fluid is pumped into the cleaning chamber 30 through the cleaning-fluid distributor 39 and jetted onto the surface and into the inside of a spray gun 40 through the cleaning outputs 18a-18c and the io internal cleaning output 42. The cleaning-fluid is also jetted through the accessory cleaning output 44 to clean accessories such as a paint pot 48.

The water-based surfactant of the high pressure jet of cleaning-fluid breaks the bond between the paint and the surface of the spray gun 40 to which it has adhered, breaking the paint off in flakes. This is an important aspect ofthe invention, because it allows filtering and non-hazardous disposal as the paint flakes can be filtered and removed to reduce solids and significantly contribute towards making the fluid non-hazardous.

A wash cycle typically takes between 2 and 5 minutes. During this time, the paint flakes off in relatively large flakes which are caught in the 50 to 100pm gauze filter base 34. The used cleaning-fluid then drains into the collection tray 35 and is guided therefrom through the chamber outlet 38 back into the reservoir for recirculating. In the embodiment in which the collection tray 35 is in the form of a weir (Figure 2), the collection tray 35 collects a depth of used cleaning-fluid up to the height ofthe raised fluid outlet 36. In use, the used cleaning-fluid drains into the collection tray 35 and the heavier and larger particles of paint 54 sink and collect on the bottom ofthe tray whereby the cleaner, used cleaning-fluid on, or close to, the surface of the collected fluid overflows into the chamber outlet 38 and into the reservoir 12 for recirculating. By removing the solid, larger and heavier paint particles from the used cleaning fluid the contamination in the reservoir is significantly reduced and the useable lifetime of the cleaning fluid can be increased by up to 50%.

The pressure of the cleaning fluid flowing through the cleaning conduit is monitored.

When the pressure exceeds a predetermined threshold the pressure actuated indicator notifies a user. Actuation ofthe pressure actuated indicator is indicative of, for example, a blockage in the cleaning conduit and/or one or more of the filters needing replacement or maintenance.

Therefore, the apparatus, cleaning fluid, system and method according to the present invention provides for a means of cleaning spray guns which is biodegradable having zero VOC emissions. After filtration and end of life cycle, the cleaning fluid is classified as nonhazardous for waste disposal. Therefore, the present invention provides an environmentally friendly solution and eliminates the relatively lengthy administration processes required in the industry and the cost of specialist disposal when disposing of current waste cleaning fluids used with current cleaning apparatus. Moreover, the present invention provides further advantages in that both solvent- and water-based spray guns can be cleaned together thus eliminating the need for separate cleaning apparatus and processes. Also, the present invention is advantageous because it provides a healthier alternative for users compared with current systems in that health and safety risks to the operator are greatly reduced, no air extraction required for the cleaning-fluid, and there is no risk of inhalation of toxic vapours and no risk of fire. A Venturi hood may be used for solvents introduced on equipment to be cleaned.

The following tests were carried out:

cleaning fluid according to the present invention comprising 10% by weight N, N-dimethyl 10 9-decenamide, 89% by weight water and 1 % by weight additives was recirculated at 10 psi pressure through an apparatus of the present invention as described in the figure 1, for 2 hours, over a Universal Air Tools spray gun of conventional type which had been dipped in specified paints (PPG Brand) and allowed to dry for 24 hours.

Paint / Cleaning Fluid	Gun wash	Water with 10% conventional alkyl benzene sulphonate surfactant and anti-foam	Cleaning-fluid of the present invention
Aqueous based paint	Limited removal remaining paint residues	Complete removal	Complete removal
Reactive paint	Very limited removal notable paint residues	Negligible removal, notable paint residues	Nearly complete removal
Non-aqueous based paint	Complete removal	Negligible removal, notable paint residues	Complete removal

The above table shows that the composition and apparatus of the present invention is effective across the typical paints used in the automotive industry.

Claims

Claims:

1. An aqueous, spray gun cleaning-fluid for removal of aqueous and non-aqueous based paint residues in cleaning a spray gun, the aqueous cleaning-fluid comprising at least 5% by weight of an amphiphilic solvent.

2. The cleaning-fluid of claim 1 in which the amphiphilic solvent is selected from one or more of N, N dialkyl C8 to C10 amide, N, N dimethyl lactamide, 2 ethyl hexyl lactate, gamma butyro lactone, tetrahydrofurfuryl alcohol, glyceryl carbonate, methyl caprylate caprate, alkyl amine and alkyl amine cationic derivatives.

3. The cleaning-fluid of claim 2 in which the amphiphilic solvent is one or more of N, N dialkyl C8 to C10 amide or N, N dimethyl lactamide.

4. An aqueous cleaning-fluid as claimed in claim 1, wherein the amphiphilic solvent is N, Ndimethyl 9-decenamide.

5. An aqueous cleaning-fluid as claimed in any one of claims 1 to 4, further comprising at least one of an antifoaming agent and an anticorrosion agent.

6. An aqueous cleaning-fluid as claimed in claim 5, wherein the antifoaming agent comprises poly-dimethyl siloxane.

7. An aqueous cleaning-fluid as claimed in claim 5 or 6, wherein the anticorrosion agent comprises an alkyl-ethoxylate.

8. The aqueous cleaning-fluid as claimed in claims 1 to 7, wherein the amphiphilic solvent is present at a level of from 5 to 35% by weight of the fluid.

9. The aqueous cleaning-fluid as claimed in claim 8 wherein the amphiphilic solvent is present at a level of from 10 to 20% by weight of the fluid.

10. The aqueous cleaning-fluid as claimed in any of claims 1 to 9 in which the fluid comprises from 64% to 95% water.

11. The use of the aqueous cleaning-fluid of any of claims 1 to 10 as a cleaning solvent for removing dried paint from automotive spray paint equipment, including pneumatic spray guns.

Intellectual

Property

Office

Application No: GB1804410.7 Examiner: Mr Rhys J. Williams