LIQUID SPRAY ASSEMBLY AND COMPATIBLE LIQUID FORMULATIONS

Abstract

A liquid spray assembly (la) comprises a liquid spray apparatus and a liquid, for example a paint. The spray apparatus comprises a reservoir (100) for the coating liquid, a spray applicator (300), and means for urging liquid from the reservoir (100) to the spray applicator (300). At the outlet of the spray applicator (300) the liquid is atomised by a flow of primary pressurised gas; and downstream the atomised spray profile is modified by a flow of secondary pressurised gas. It has been determined that the effective use of this type of spray apparatus can be achieved by using a particular class of coating liquids, which have a defined solids content, viscosity and amount of an organic or organically modified thickener, of which over 50 wt% is an organic or organically modified associative thickener. A method of using the liquid spray apparatus is also described.

Claims

1. A liquid spray assembly comprising a liquid spray apparatus and a liquid to be sprayed therefrom, wherein the liquid spray apparatus comprises: a reservoir having a liquid outlet a spray applicator connected to the reservoir to receive liquid therefrom means for urging liquid from the reservoir to the spray applicator an outlet in the spray applicator for the expulsion of liquid a primary gas outlet in the spray applicator for atomising expelled liquid a secondary gas outlet in the spray applicator for impinging upon the expelled and atomised liquid and modifying its spray profile wherein the liquid satisfies each of the following parameters: a) the solids content of the liquid is in the range from 30 wt% to 65 wt%, based on the total weight of the composition b) the liquid has a low shear viscosity (measured on a Physica Rheolab MC1 viscometer using a E100 spindle at a rotation speed of 181 rpm at 23° C.) in the range from 5 dPa.Math.s to 50 dPa.Math.s c) the liquid contains from 0.03 to 2 wt% (based on the total weight of the composition) of an organic or organically modified thickener where over 50 wt% (based on the total weight of said organic or organically modified thickener) is an organic or organically modified associative thickener.

2. An assembly according to claim 1, wherein the liquid has a solids content of at least 38 wt.

3. A liquid spray assembly according to claim 1, 1, wherein the liquid has a solids content of up to 60 wt%.

4. An assembly according to claim 1, wherein the liquid has a low shear viscosity (measured as defined herein) of at least 8 dPa.s.

5. An assembly according to claim 1.sub., wherein the liquid has a low shear viscosity (measured as defined herein) of up to 40 dPa.s.

6. An assembly according to claim 1, wherein the liquid contains at least 0.05 wt% of organic or organically-modified associative thickener based on the total weight of the composition.

7. An assembly according to claim 1, wherein the liquid contains up to 1 wt% of organic or organically-modified associative thickener based on the total weight of the composition.

8. An assembly according to claim 1, wherein at least 60 wt% of organic or organically-modified thickener present are organic or organically-modified associative thickener.

9. An assembly according to claim 1, wherein the organic or organically modified associative thickener comprises a Hydrophobically modified Alkali Swellable Emulsion (HASE) thickener and/or a Hydrophobically modified Ethylene oxide Urethane Rheology (HEUR) thickener.

10. An assembly as claimed in claim 1, wherein the liquid spray apparatus comprises: a main body which houses the reservoir, and a displacement member moveable within the main body for varying the volume of the reservoir thereby urging the liquid through the liquid outlet of the reservoir and towards the spray applicator.

11. An assembly as claimed in claim 10, wherein the displacement member has a liquid contacting side and a gas contacting side, and wherein the main body comprises a gas inlet in fluid communication with the gas contacting side of the displacement member; wherein the liquid spray apparatus comprises pressurised gas in fluid communication with the gas contacting side of the displacement member and arranged to be operable to move the displacement member and thereby advance the liquid from the reservoir to the spray applicator.

12. An assembly as claimed in claim 1, 1, wherein pressurised gas urges the liquid to the spray applicator and is delivered to the primary and secondary gas outlets.

13. An assembly as claimed in claim 1, 1, wherein the spray applicator comprises an actuator to control the flow of liquid, primary gas and secondary gas to the outlet of the spray applicator, the actuator being biased towards its off position.

14. An assembly according to claim 1, 1, wherein the pressure of gas in the primary gas conduit is up to 1.5 bar (1.5 × 10.sup.5 Pa) over atmospheric pressure; and the pressure of gas in the secondary gas conduit is up to 1.5 bar (1.5 × 10.sup.5 Pa) over atmospheric pressure.

15. An assembly according to claim 1, 1, wherein, in use, the liquid and the primary gas produce a divergent spray and the secondary gas modifies the shape of the spray.

16. An assembly according to claim 1, 1, wherein, in use, secondary gas outlets are provided at the outlet end of spray applicator downstream of the outlet for the liquid and downstream of the outlet for the primary gas and arranged such that secondary gas outlets are generally face each other and produce generally opposed gas flows which are transverse to the flow of the atomised spray, and impinge onto the atomised spray and urge it into a generally elliptical or fan shape.

17. An assembly according to claim 1, 1, the assembly being such that on commencement of an individual action of liquid spraying, primary gas is expelled by the spray applicator at the same time as liquid or is expelled before any liquid is expelled; and such that on termination of that individual action of spraying, primary gas flow from the spray applicator is terminated at the same time as liquid flow is terminated, or after liquid flow is terminated.

18. An assembly according to claim 1 1, the assembly being such that on commencement of an individual action of liquid spraying, secondary gas is expelled by the spray applicator at the same time as liquid or is expelled before any liquid is expelled; and such that on termination of that individual action of spraying, secondary gas flow from the spray applicator is terminated at the same time as liquid flow is terminated, or after liquid flow is terminated.

19. A liquid spray assembly comprising a liquid spray apparatus and a liquid to be sprayed therefrom; wherein the liquid spray apparatus comprises: a reservoir containing a liquid and having a liquid outlet, wherein the coating liquid is a paint, varnish or lacquer a spray applicator connected to the reservoir to receive liquid therefrom a source of compressed air for urging liquid from the reservoir to the spray applicator a liquid outlet in the spray applicator for the expulsion of liquid a primary air conduit leading to a primary air outlet in the spray applicator adjacent to the liquid outlet, for atomising expelled liquid to form an atomised spray, using the same source of compressed air, wherein the air in the primary air conduit is at a pressure in the range from 0.7 to 1.3 bar (0.7 -1.3 × 10.sup.5 Pa) a secondary air conduit leading to a secondary air outlets in the spray applicator, wherein the air in the secondary air conduit is at a pressure in the range from 0.7 to 1.3 bar (0.7 - 1.3 × 10.sup.5 Pa), supplied by the same source of compressed air; wherein the secondary air outlets expel air in opposed air streams onto the atomised spray transversely relative to the flow of the atomised spray, and from opposite sides of the atomised spray; a spring-loaded actuator provided on the spray applicator and having an off-position for preventing the expulsion of liquid, primary air and secondary air from the spray applicator and an on-position for permitting the expulsion of liquid, primary air and secondary air from the spray applicator, the actuator being biased towards- its off-position; wherein liquid can only be expelled when primary air and secondary air are expelled optionally, a liquid control valve to control the air pressure applied to advance the liquid; optionally, a primary air control valve to control the primary air pressure; and optionally, a secondary air control valve to control the secondary air pressure. wherein the liquid satisfies each of the following parameters: a) the solids content of the liquid in the range from 30 wt% to 65 wt% based on the total weight of the composition b) the liquid has a low shear viscosity (measured on a Physica Rheolab MC1 viscometer using a E100 spindle at a rotation speed of 181 rpm at 23° C.) in the range from 5 dPa.Math.s to 50 dPa.Math.s c) the liquid contains from 0.03 to 2 wt% (based on the total weight of the composition) of at least one organic or organically modified thickener where over 50 wt% (based on the total weight of said organic or organically modified thickener) is an organic or organically modified associative thickener.

20. A method of using a liquid spray assembly as defined in claim 1, 1, comprising the steps of: providing the liquid spray apparatus with a reservoir of a coating liquid to be sprayed moving the liquid towards the spray applicator activating the spray applicator, thereby to: expel liquid from the outlet valve of the spray applicator expel primary gas from a primary gas outlet of the spray applicator, for atomising the liquid being expelled; and expel secondary gas from a secondary gas outlet of the spray applicator for impinging upon the expelled and atomised paint and modifying its spray profile.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0263] For a better understanding of the invention, and to show how example embodiments may be carried into effect, reference will now be made to the accompanying drawings in which:

[0264] FIG. 1 shows a perspective view of a user spraying a surface with a first embodiment of a spray assembly, wherein a support structure of the spray assembly is floor-standing and not wearable on the user;

[0265] FIG. 2 shows a cross-sectional view of the liquid reservoir of FIG. 1;

[0266] FIG. 3 shows a perspective view of the support structure of FIG. 1 wherein a hatch of the support structure is in an open position for accessing a reservoir provided as a cartridge housed by the support structure;

[0267] FIG. 4 shows the support structure of FIG. 3 alternatively housing a second cartridge of relatively smaller volume than the cartridge shown in FIG. 3 wherein the hatch is in a closed position;

[0268] FIG. 5 shows the main unit of FIG. 3 wherein the support structure comprises a control unit which is attachable to a receptacle holding part of the support structure;

[0269] FIG. 6 shows a second embodiment of the spray assembly, wherein a support structure of the second embodiment comprises a floor contacting part comprising wheels;

[0270] FIG. 7 shows a receptacle holding part of the support structure of the second embodiment for housing a plurality of cartridges;

[0271] FIG. 8 shows a control unit of the second embodiment attached to a user;

[0272] FIG. 9 shows a third embodiment of the spray assembly, wherein a support structure and a control unit are wearable on a user, wherein a gas pressuring device is floor-standing and not wearable on the user;

[0273] FIG. 10 shows a fourth embodiment of the spray assembly, wherein a support structure and an gas pressurising device powered by an energy storage unit are wearable on a user;

[0274] FIG. 11 shows the support structure and gas pressurising device of FIG. 10;

[0275] FIG. 12 shows alternative embodiments of the support structure;

[0276] FIG. 13 shows a control unit of the fourth embodiment;

[0277] FIG. 14 shows a flow chart of a method of using a liquid spray assembly which comprises a liquid spray apparatus and a liquid;

[0278] FIG. 15 is a perspective view of a fifth example of spray assembly;

[0279] FIG. 16 is an enlarged perspective view of an upper rear portion of the support structure of structure of the spray assembly of FIG. 15;

[0280] FIG. 17 is an enlarged perspective view of a lower side portion of the support structure of the spray assembly of FIGS. 15 and 16; and

[0281] FIG. 18 is a perspective view of the spray assembly of FIGS. 15-17 with its reservoir access hatch open;

[0282] FIG. 19 shows a backpack mounting board of the spray assembly of FIGS. 15-18;

[0283] FIG. 20 shows a spray applicator suitable for use in the invention in a frontal perspective view;

[0284] FIG. 21 shows the spray applicator of FIG. 20 in frontal elevation.

DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE SPRAY ASSEMBLY

[0285] At least some of the following example embodiments provide an improved liquid spray assembly, method of using a liquid spray assembly and a kit of parts for a liquid spray assembly. The example assemblies are simple and convenient for the user. Additionally, the effect of splashback and overspray is reduced. Other advantages and improvements will be discussed in more detail herein.

[0286] Such spray assemblies comprise liquid spray apparatus and a coating liquid to be sprayed onto a surface.

[0287] A spray assembly 1a according to a first embodiment is shown in FIG. 1. The spray assembly comprises a receptacle 100 for containing liquid to be sprayed onto a surface. The receptacle is shown as a bottle in the form of a cartridge. Using a cartridge is advantageous because the liquid can be easily changed, particularly when the liquid remaining in the receptacle is low. The cartridge may comprise a tamper-proofing means (not shown). The tamper-proofing means may be disturbed when inserting the cartridge. Alternatively, the tamper-proofing means may be removed manually by a user before inserting the cartridge. In FIG. 1, a cylindrical receptacle is shown. The capacity of the receptacle is 4 litres, although a 2 litre receptacle can be equally used. Advantageously, the apparatus is capable of holding cartridges of varying capacity and/or size.

[0288] The receptacle 100 shown in FIG. 1 is installed in a support structure 200a. The support structure is a floor-standing support structure. That is, the support structure has a predetermined resting position. The resting position equates to a vertical orientation of the receptacle when installed in the support structure.

[0289] The spray assembly 1a further comprises a spray applicator 300 that is holdable by the hand of the user. The spray applicator is a spray gun. The spray gun comprises a trigger 340 for activating the release of the liquid away from a liquid outlet valve (not shown) of the spray gun. The trigger may be biased towards a first position that is a non-activating position. The biasing means may be a resilient member such as a spring. The spray gun has a liquid outlet 320 that is arranged at an opposite end to a liquid inlet 310.

[0290] The spray assembly 1a comprises a source of pressurised gas 400a. In this example the gas is air, and the source of compressed gas is an air compressor. The compressor supplies the receptacle 100 with air pressure so that the liquid can be driven out of the receptacle and towards the spray applicator 300. The compressor is shown to be powered by mains electricity and comprises an electrical connector 404 that supplies electricity through an electrical cable 402. However the compressor may be powered by a battery rather than mains electricity. Alternatively the air pressurising device may be a canister of pressurised air. The canister is advantageous because it is portable and can be easily used outside without the risk of electrical shock.

[0291] The spray assembly 1a is further shown with transmission lines 410, 420a, 520a. The transmission lines are hoses that convey air or liquid around the spray assembly. For example, a first air transmission line 410 provides fluid communication between the compressor and the receptacle 100. A second air transmission line 420a and a first liquid transmission line 520a fluidly link the receptacle and the spray applicator 300. A three-way connector may separate the first and second air transmission lines so that air supplied under pressure from the compressor is diverted from the first air transmission line towards the receptacle to drive a displacement member 130 of the receptacle and force liquid out of the receptacle. Second air transmission line 420a is divided into two separate sub-lines prior to entry into the spray applicator so as to provide separate primary and secondary air flows within the spray applicator.

[0292] Finally, a control unit 600a with control dials 610a is shown that is attached to the support structure 200a. Although three control dials are shown, at least one control dial may be used to simplify the options for adjustment. The control unit is removable from the support structure. That is, the control unit can be coupled and decoupled to the support structure. This allows the control unit to be removed for maintenance, repair or update.

[0293] The receptacle 100 is shown in cross-section in FIG. 2. The receptacle comprises a main body 110 that is an outer part of the receptacle. The main body may be made from metal. The receptacle further comprises a displacement member 130 that is provided as a bladder. The displacement member is configured to expand and contract as liquid fills and leaves (through a liquid outlet (not shown) of) a reservoir 120, respectively. In the example shown, the receptacle is provided by the displacement member alone and not the main body. However, the reservoir 120 may alternatively be formed by the main body and the displacement member, for example, if the displacement member is provided as a piston. The displacement member therefore has a air contacting side 134 and a liquid contacting side 132. The main body also has a air contacting side 112 that comes into contact with the displacement member. To allow the displacement member to move freely away from the air contacting side of the main body, the air contacting side comprises a coating that is a non-stick coating to avoid the adhesion of the displacement member to the main body.

[0294] FIG. 2 further shows an air inlet 140. The air inlet allows air to enter the receptacle 100 from the compressor. The air contacts the air contacting side 112 of the main body 110 and the air contacting side 134 of the displacement member 130 to force the displacement member to move. In the example shown, the displacement member is a bladder and comprises a flexible membrane allowing the displacement member to be manipulated so that the displacement member can expand and contract by air pressure. The air inlet comprises a one-way valve 142 for restricting air flow and preventing air flow out of the receptacle. This prevents the reservoir 120 being filled without circumventing (i.e. overcoming) the one-way valve because the displacement member is prevented from expanding when liquid enters the reservoir. Advantageously, the cartridge may not be refillable by the user without a special tool to open the one-way valve.

[0295] The support structure 200a of the first embodiment is shown in more detail in FIGS. 3 to 5. As previously mentioned, the support structure is shown with a removable control unit 600a that regulates the flow of air and/or liquid of the spray assembly 1a. Transmissions lines 420a, 520a are shown to transport the air and liquid around the system, towards the spray applicator. Furthermore, a 2 litre cartridge 100-12 and a 4 litre cartridge 100-14 are shown. The support structure comprises a handle 244 for ease of transportation. The cartridge is removed by opening a door 240, shown as a hatch. The door may comprise a window for visual inspection of the inside of the support structure. The door comprises an opening means 242. The opening means may be a handle. However, the opening means may be a button to release the hatch. The door is hinged to allow the door to pivot and provide an opening through which to pass the receptacle 100. The support structure 200a comprises an accommodating part 220 for receiving the receptacle (i.e. housing the receptacle) and a ground contacting part 230a for abutment against a ground surface. The accommodating part is therefore a receptacle holding part 220. A further liquid transmission line 510a is shown that is arranged to convey liquid from the receptacle to the control unit.

[0296] A spray assembly 1b according to a second embodiment is shown in FIG. 6. The spray assembly of the second embodiment differs from the spray assembly 1a of the first embodiment in that the air pressurising device 400b is powered by liquid fuel, such as diesel or airoline, the support structure 200b is arranged in the form of a trolley and the control unit 600b (see FIG. 8) is wearable on the user.

[0297] A first air transmission line 410 connects the air pressurising device 400b and the support structure 200b. Although not shown, a first liquid transmission line 510b is connected between a liquid outlet portion of the reservoir 120 and a connecting member 210 shown in FIG. 7. A second liquid transmission line 520b is configured to transmit liquid away from the connecting member and towards the liquid inlet 310 of the spray applicator 300. Similarly, a second air transmission line 420b is configured to transmit air from the connecting member and towards the spray applicator to propel liquid out of the liquid outlet valve of the spray applicator. Both the second liquid transmission line and the second air transmission line comprise a pair of transmission sub-lines. A first air transmission sub-line 420b-1 is connected upstream of the control unit 600b and a second air transmission sub-line 420b-2 is connected downstream of the control unit. Likewise, a first liquid transmission sub-line 520b-1 is connected upstream of the control unit and a second liquid transmission sub-line 520b-2 is connected downstream of the control unit. A control dial 610b is used to control the passage of liquid and/or air. Second air transmission line 420b is divided into two separate sub-lines prior to entry into the spray applicator so as to provide separate primary and secondary air flows within the spray applicator.

[0298] The support structure 200b comprises a telescopic handle for ease of storage. The support structure comprises a receptacle holding part 220 (i.e. an accommodating part) and a ground contacting part 230b. Unlike the support structure 220a of the first embodiment, the support structure of the second embodiment is capable of holding a plurality of receptacles 100 at once. Each receptacle may be a different size as shown in FIG. 7. The receptacle holding part comprises a door that allows access to the inside of the receptacle holding part (i.e. the region accommodating the at least one receptacle). The door does not comprise a window. The ground contacting part comprises a plurality of wheels. The wheels may be connected by a common axle. Alternatively, the wheels may rotate independently and therefore have separate axles. The ground contacting part further comprises a foot provided away from the wheels. The foot does not move relative to the receptacle holding part but is configured to rest against a ground surface when the support structure is in a standing position.

[0299] A spray assembly 1c according to a third embodiment is shown in FIG. 9. The spray assembly differs from the spray assembly 1a of the first embodiment in that the support structure 200c and control unit 600c are both wearable on a user (the support structure comprises a ground contacting part 230c for resting the support structure on ground in a resting position). The support structure is worn by the user using shoulder straps 260c and the control unit is worn using a belt 270c. The air pressurising device 400a of the first embodiment is shown. However, the air pressurising device 400b of the second embodiment can equally be used. The air pressurising device is powered by mains electricity and comprises an electrical connector 404 that supplies electricity through an electrical cable 402.

[0300] The first air transmission line 410 of the third embodiment is connected between the air pressurising device 400a and the control unit 600c. The control unit therefore acts as a hub about which the network of transmission lines is arranged. A second air transmission line 420c comprises a first air transmission sub-line 420c-1 which transmits air towards the receptacle 100 and a second air transmission sub-line 420c-2 transmits air towards the spray applicator 300. Additionally, a first liquid transmission line 520c comprises a first liquid transmission sub-line 520c-1 which transmits liquid rom the receptacle 100 to the control unit and a second liquid transmission sub-line 520c-2 transmits liquid from the control unit to the spray applicator. Therefore, the first and second liquid transmission sub-lines flow in and out of the control unit whereas the first and second air transmission sub-lines both flow out of the control unit since the first air transmission line supplies the control unit with air from the air pressurising device. Second air transmission line 420c is divided into two separate sub-lines prior to entry into the spray applicator so as to provide separate primary and secondary air flows within the spray applicator.

[0301] Finally, a spray assembly 1d according to a fourth embodiment is shown in FIG. 10. The spray assembly of the fourth embodiment is similar to the spray assembly 1c of the third embodiment in that the support structure 200d and control unit 600d (including at least one control dial 610d as shown in FIG. 13) are both wearable on a user. The support structure is provided as a backpack. The backpack includes shoulder straps 260d and a belt 270d. The air pressurising device 400d of the fourth embodiment is powered by a battery. This allows the spray assembly to be portable and the air pressurising device can be carried by the user. The support structure comprises a plurality of compartments, each for the receptacle and the air pressurising device with battery. A lower compartment is the ground contacting part 230d. The air transmission line to the spray applicator is divided into two separate sub-lines prior to entry into the spray applicator so as to provide separate primary and secondary air flows within the spray applicator.

[0302] FIG. 12 shows two variations of the shoulder straps 260e, 260f and belt 270e, 270f combination of FIGS. 9 and 10. These variations comprise holders for further receptacles 100 or generally pockets for storing other items of use. The shoulder straps and belt are comfortable and convenient for a user.

[0303] FIG. 14 shows a method 1000 of using a liquid spray assembly. The method includes filling the receptacle with liquid (S100), such as a coating composition such as a paint or varnish. The filling step may be performed using a one-way valve so that an end-user cannot easily re-fill the receptacle because the one-way valve may require a special tool to overcome. Once the receptacle is filled, the receptacle can be loaded into a support structure (S200). When the receptacle comprises a tamper-proofing means, the step of loading the receptacle may disturb the tamper-proofing means and allow the liquid to be released from the receptacle. Once the receptacle is loaded, air is supplied to a displacement member of the receptacle from a source of pressurised air (S300). The source of pressurised air may be a compressor and the air may be air. The supply of air under pressure results in the movement of the displacement member relative to a main body of the receptacle (S400). The displacement member therefore acts as a bladder and expands and contracts under pressure. As a result of the movement of the displacement member, liquid is guided from the reservoir towards a spray applicator (S500). To release the liquid from the spray assembly, a trigger on the spray applicator is activated (S600), such as by hand. The liquid is then expelled from an outlet valve of the spray applicator using air from the source of pressurised air as a propellant (S700). The liquid can be directed to a surface to be coated. Once a liquid level in the receptacle is sufficiently low, the receptacle can be replaced. Therefore, it is convenient if the receptacle is a cartridge so that the receptacle can be swapped with ease. Separately, air is fed to the spray applicator to modify the expelled liquid, as will be described in more detail.

[0304] A further example of a liquid spray assembly 1e is shown in FIGS. 15-19. The liquid spray assembly 1e corresponds largely in structure and function to the liquid spray assemblies 1a-1d described herein, and therefore only the differences will be discussed in detail. Furthermore, FIGS. 15-19 omit the transmission lines and air pressurising device so as to facilitate an unobstructed view of the features of the liquid spray assembly 1e.

[0305] As can be best seen in FIGS. 15-18, liquid spray assembly 1e comprises a support structure 200e, configured to retain a receptacle 100e. Similarly to the support structure 200a, the support structure 200e takes the form of a generally cuboid structure, albeit with the base 201e of the support structure 200e having a larger surface area than the top 202e. The generally vertical sidewalls 203e of the support structure 200e have a longer vertical extent than the horizontal extent of the top 202e and bottom 201e, so that the support structure 200e has a generally “portrait” orientation when viewed from the front or side. Similarly to the support structure 200d, the support structure 200e is configured so that it can be either worn on the back of the user or rested on the floor or another support surface in use. In other words, the support structure 200e is operable in two configurations, a worn configuration and a floor-resting configuration.

[0306] The support structure 200e defines a housing or enclosure that has an internal volume that accommodates the receptacle 100e. This enclosure is accessible by opening the door 240e. As can be best seen in FIG. 18, the door 240e is pivotally attached to the support structure 200e towards the base 201e, so that the upper edge 241e of door 240e can move away from and forward of the support structure 200e.

[0307] The internal volume of the support structure 200e comprises an accommodating part 220e that is configured to retain the receptacle 100e. The accommodating part 220e is shaped to engage with the receptacle 100e so as to hold it securely in position during operation of the spray assembly 1e. For example, the accommodating part 200e may take the form of recess having a shape that is at least partially complementary to the shape of the receptacle 100e, so as to securely engage the main body of the receptacle 100e.

[0308] It will be appreciated that the recess may not exactly correspond to the shape of the receptacle 100e - for example the recess may be able to accommodate expansion of the receptacle 100e in use. Furthermore, it will be appreciated that in some examples the accommodating part 200e comprises elements on the interior surface of the door 240e that are configured to engage with the receptacle 100e when the door 240e is closed.

[0309] In one example, the support structure 200e comprises a spray applicator holder 250e, configured to retain the spray applicator 300e when not in use. The spray applicator holder 250e is located at an upper portion of one of the sidewalls 203e. Furthermore, the holder 250e comprises a stop member 251e (best seen in FIG. 16), which prevents activation of the trigger 340e of the spray applicator 300e, when the spray applicator is in the holder 250e. For example, stop member 251e is a projection that extends between the trigger 340e and a handle 330e of the spray applicator 300e. Accordingly, the stop member 251e prevents the trigger 340e being depressed towards the handle 330e, thereby preventing activation of the trigger 340e.

[0310] In one example, the spray assembly 1e comprises an emergency cut off button 255e, which is shown in detail in FIG. 17. For example, the emergency cut off button 255e is disposed at a lower portion of one of the sidewalls 203e. Accordingly, when the support structure 200e is worn on the back of the user, the user can easily reach the button 255e to activate it. The emergency cut off button 255e is configured to cut off the air supply received from the air pressurising device 400 upon activation of the button, for example by activating a shut-off valve. Consequently, liquid will no longer be forced out of the receptacle 100e, and the spray applicator 300e will no longer propel the liquid therefrom.

[0311] In one example, a guard portion is positioned around the emergency cut off button 255e. The guard portion extends further from the sidewall 203 than the button 255e, so as to prevent accidental activation of the button 255e. In one example, the guard portion takes the form of a pair of projections 256e arranged at opposite sides of the button 255e.

[0312] In the structure of FIGS. 17 and 18 the receptacle 100e takes the form of a generally cylindrical main body, with a domed top portion. A neck is formed at the peak of domed top portion, wherein the neck forms the liquid outlet of the receptacle 100e.

[0313] The bottom end, which is disposed at the opposite end of the main body to the top portion, comprises the air inlet 140e. The air inlet is arranged on the underside of the receptacle 100e.

[0314] Turning now to FIG. 19, there is shown an exemplary backpack mounting unit 280e. The backpack mounting unit 280e comprises a board 281e having a plurality of apertures 282e, which are configured to retain suitable shoulder and hip straps (not shown). The backpack mounting unit 280e is connectable to the rear of the support structure 200e, for example via mounting rail 283e, which is slidably engageable in a corresponding recess 204e disposed on a rear side wall 205e of the support structure 200e. This allows the support structure 200e to be rapidly converted from a floor standing support structure to a wearable support structure.

[0315] Whilst the liquid stored in the receptacle 100 described above may be a liquid for coating a surface, it will be appreciated that a receptacle 100 comprising a cleaning solution for cleaning the spray apparatus 1 may also be supplied. Particularly, some liquids used by the spray apparatus 1 may dry and set in the liquid transmissions lines of the apparatus when the apparatus is stored between uses. Accordingly, a receptacle 100 comprising a cleaning solution may be received in the apparatus 1, such that the cleaning solution may be drawn through the apparatus 1 in order to flush the apparatus 1.

[0316] It can be seen in FIGS. 20 and 21 that the spray applicator 300e has a generally circular spray head. Liquid is sprayed forwardly from the spray head, in use. The spray head has two projections or ‘horns’ 365e projecting from the generally circular face of the spray head. The horns are spaced apart in diametrically opposed positions. The spray applicator, which can be used with any of the embodiments herein, will be described in greater detail, with reference to FIGS. 20 and 21.

[0317] The spray applicator 300e is generally of pistol design having a pistol-type grip handle 310e and a barrel 320e transverse to the handle. The handle is provided with a spring-biased trigger 340e which is depressed in order to permit liquid to be released. The distal or outlet end of the barrel — the spray head —has openings for the expulsion of liquid and air.

[0318] Thus in the generally circular face 350e of the spray head of the barrel there is provided an outlet in the form of a single central nozzle 355e for liquid. In close proximity to the nozzle are two clusters 360e, 362e of openings for primary (atomising) air. They are arranged diametrically to each other. One cluster 360e is on one side of the nozzle. The other cluster 362e is on the other side of the nozzle. Each cluster comprises three smaller holes adjacent to the nozzle and one larger hole located further from the nozzle. The openings 360e, 362e and nozzle 355e are coplanar and as soon at the liquid is expelled from the nozzle it is swept up by the primary air issuing from openings 360e, 362e, and atomised. The atomised output is initially conical and divergent but it is altered by a further delivery of air, from the air horns 365e. It will be seen that the air horns are two blocks projecting forwardly of the generally circular face of the spray head, and diametrically opposed to each other. The inner and outer faces of each air horn are convex and follow the circular shape of the spray head. The inner face of each air horn has two apertures; a smaller one nearer to the face 350e and the larger one further from the face 350e. Thus the two air horns together have two air outlets each and from those outlets air is expelled in opposing directions, towards the conical spray, and transverse to it. This has the effect to modifying the spray into an elliptical or fan shape.

[0319] It should be noted that the flow of liquid is separate from the flow of primary and secondary air within the spray applicator. The liquid is separate until the primary air atomises the liquid as it leaves the nozzle. The secondary air is delivered to the mixture of liquid and primary air subsequently.

[0320] The spray applicator has entirely separate conduits for the primary and secondary air.

[0321] When the trigger is released by the operator it is moved by a spring to its rest position (its off position, and its outmost position). This action closes the conduit for liquid, and the two conduits which separately deliver primary air (for atomising), and secondary air (for deflecting).

[0322] The spray applicator may be designed such that the initial depression of the trigger permits air release — such as both primary air and secondary air - but no release of liquid. Further depression of the trigger produces liquid release, as well as release of primary and secondary air. On termination of painting the reverse applies: liquid release is terminated before primary and secondary air release is terminated.

[0323] The pressure of the primary air is the same as that of the secondary air in this embodiment, both typically being 1 bar (above atmospheric pressure). However there is provision in the upstream apparatus for varying these air pressures independently of each other.

[0324] In these examples the air pressure used to advance the liquid is typically 2 bars (above atmospheric pressure). There is provision in the upstream apparatus for varying this pressure in order to change the operating characteristics. Such variation may be effected independently of any variation in the primary and secondary air pressures.

[0325] The quantity of liquid sprayed from the spray applicator may be further controlled by a regulator valve provided in the spray applicator. The regulator valve has a needle valve whose distal end is adjacent the nozzle and whose proximal end is under the control of a dial. The dial is located at the end of the barrel remote from the spray head. Turning the dial advances or withdraws the needle. The needle valve is housed within an annular chamber extending substantially within the major extent of the barrel. This is a known valve and is described in WO 2016/024107 A1, which may be consulted if needed.

[0326] Thus the operator may have a number of control elements at his or her disposal, within the spray assembly, namely: [0327] an on-off actuator, for example a trigger, which permits or prohibits flow of liquid, primary air and secondary air [0328] a regulator to control the pressure applied to the liquid, to deliver it to the spray applicator [0329] a regulator within the spray applicator, to control the flow of the liquid to be sprayed [0330] a regulator for the pressure of primary (atomising) air [0331] a regulator for the pressure of secondary (used to modify the spray pattern)

[0332] Paint spray apparatus as described and defined herein may be excellent in spray performance with certain paints, which are defined herein. It can spray such paints smoothly and accurately, with little spread of paint on the substrate, low misting (paint released into the air), good levelling and good thickness control. Other paints are less optimally sprayed. The further examples examine the performance of paint compositions within the paint apparatus described above.

Experimental Work on Paint Compositions

[0333] The invention is further illustrated by the following Examples.

[0334] Sprayable liquids, in the form of aqueous non-Newtonian pigmented paints, were prepared by mixing together the constituents as listed in the Tables 1-4.

[0335] The low shear viscosity of the paints was measured with Physica Rheolab MC1 viscosimeter using an E100 spindle at a rotation speed at of 181 rpm at 23° C.

[0336] The solids content of the formulations was calculated from the percentage solids material of the constituents and the quantity of solids is expressed as a weight percentage based on the total formulation. For example the binders and the associative polymers are liquid dispersions of known solids content. Some components are solids, for example mica and clay - thus having 100% solids content. Other components are liquids with no solid content — for example water, and ammonia 25% - 0% solids content. From such information the solids content of the examples was calculated, and is stated in the tables below.

[0337] For application, a paint was filled into a 2 litre reservoir of the receptacle of the type described above and positioned in the receptacle holding part of the support structure. Using the air pressurising device, the reservoir in the main body of the liquid spray was pressurised to a nominal pressure of 2 bar (that is, 2 bar above atmospheric pressure) and the liquid outlet valve of the spray applicator was opened allowing the paint to be propelled from the reservoir. The paint was advanced into and through the spray applicator described herein and a spray of paint was expelled through the liquid outlet of the spray applicator with reference to FIGS. 20 and 21 described above. Primary (atomising) air was delivered to the outlets 360e, 362e, immediately adjacent to the paint nozzle. The air conduit delivering primary (atomising) air was pressurised to a nominal pressure of 1 bar (that is, 1 bar above atmospheric pressure). Downstream air was delivered to the outlets 370e, 375e, downstream of the paint nozzle. The air conduit delivering secondary air downstream was pressurised to a nominal pressure of 1 bar (that is, 1 bar above atmospheric pressure)

[0338] A successful paint should atomise well and in order to obtain a narrow spray pattern and minimal overspray, the length of the spray outline may be 17 cm ± 5 cm at a point 7 cm from the spray outlet. The paint was applied using the liquid spray assembly to a vertically positioned tin plate (100 × 72 cm) at a wet film thickness of 120 to 140 .Math.m, which was checked at random points in the film with a wet film thickness gauge.

[0339] The spray mist that was formed during the spray application in an area of about 1 m.sup.3 around the substrate was assessed visually by three impartial observers. The mist formation is assessed by means of a notation scale, from 0 (hardly any mist observed) to 5 (severe mist formation). The denoted rating is the median of the three observations and is expressed as six-step classification wherein the first three steps (0, 1 and 2) are considered as pass in a pass/fail assessment.

[0340] The levelling was appraised by the extent of fading of the coarse droplet-like spray pattern of the wet paint and the formation of a smooth film during the early stages of drying. The levelling rating is established by means of a notation scale, from 0 (excellent levelling) to 5 (very poor levelling).

[0341] The hold-up is determined visually by the degree of runs and sags in the dried paint film. A six-step classification is given, from 0 (no sags) to 5 (unacceptable).

[0342] The overspray was determined by spraying the paint onto a black Leneta foil from a distance of 7 cm from the liquid outlet resulting in a solid conical spray outline (termed: ‘the length of conical spray’) and a discontinuous and speckled periphery; overspray (in cm). To avoid wide-ranging masking during spray application, the drift onto unintended objects should be minimal and an overspray of maximal 7 cm is considered to be acceptable.

[0343] In the following examples shown in Tables 1-4 the type of HEUR associative thickener used was ACRYSOL RM-12W. This is a non-ionic hydrophobically modified polyethylene oxide urethane product in water as solvent. As-supplied solids content is 19 % wt/wt, in water. In Example 8 shown in Table 5 the type of HEUR associative thickener used was ACRYSOL RM-825. This is a non-ionic hydrophobically modified polyethylene oxide urethane product in water as solvent. As supplied solids contents is 25 % wt/wt.

[0344] In the following examples the type of HASE associative thickener used was ACRYSOL TT-935 ER. This is a anionic hydrophobically modified alkali-swellable acrylic thickener. As-supplied solids content was 30 % wt/wt. The material as added to the paints had 40 % wt/wt of ACRYSOL TT-935R and 60 % wt/wt of an ethyl diglycol / water / ammonia carrier. Thus the resulting HASE composition has a solids content of 12 % wt/wt.

[0345] The ACRYSOL products are available from Dow. ACRYSOL is believed to be a Registered Trade Mark and it acknowledged as such.

[0346] In the following examples the following non-associative thickeners were used: [0347] methyl hydroxyethyl cellulose thickener, solids content 96 % wt/wt [0348] alkali-soluble emulsion acrylic thickener, solids content 28 % wt/wt [0349] organically-modified hectorite clay, solids content 100 % wt/wt

TABLE-US-00001 COMPOSITION Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Parts by Wt Parts by Wt Parts by Wt Parts by Wt Parts by Wt Water 9.4 9.0 65.3 7.3 9.6 Biocides 0.1 0.1 0.0 0.1 0.1 Organic solvents 0.5 0.5 0.2 0.5 0.5 Pigment wetting agents 1.3 1.3 0.4 1.3 1.3 Defoamer 1.4 1.4 0.5 1.4 1.4 Extender, barium sulfate 9.4 9.3 3.1 9.4 9.5 Extender, mica 4.2 4.2 1.4 4.2 4.3 Extender, nepheline syenite 15.5 15.4 5.2 15.5 15.7 Ammonia 25% 0.1 0.1 0.0 0.1 0.1 Binder, alkyd emulsion (42 wt% solids) 47.1 46.7 15.6 47.6 Binder, alkyd emulsion (60 wt% solids) 52.7 Metal drier 0.2 0.2 0.1 0.2 0.2 Surface wetting agent 0.3 0.3 0.1 0.3 0.3 Wax emulsion 2.5 2.5 0.8 2.5 Silicone additive 0.4 0.4 0.1 0.4 0.4 Colorant white 4.1 4.1 1.4 4.1 4.1 Colorant black 2.4 2.4 0.8 2.4 2.4 Associative thickener HASE 0.3 0.4 Associative thickener HEUR 0.8 0.4 5.0 0.1 Hydrophilic fumed silica 1.4 Methyl hydroxyethyl cellulose thickener Alkali-soluble emulsion acrylic thickener Organically-modified hectorite clay paint characteristics wt% solids 57.1 58.0 19.8 67.8 57.5 low shear viscosity [dPa.s] 12.1 11.8 12.1 11.3 1 wt% thickener (active agent(s)) 0.2 0.1 1.0 0.019 0 ratio associative thickener on total thickener composition 1 1 1 1 -- application performance length of conical spray (cm) 13 22 11 13 18 mist formation 0 1 3 0 2 levelling 1 1 5 4 0 hold-up 1 0 0 0 5

TABLE-US-00002 COMPOSITION Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Parts by Wt Parts by Wt Parts by Wt Parts by Wt Parts by Wt Water 9.3 9.3 9.5 11.2 9.5 Biocide 0.1 0.1 0.1 0.1 0.1 Organic solvent 0.5 0.5 0.5 0.5 0.5 Pigment wetting agent 1.3 1.3 1.3 1.3 1.3 Defoamer 1.4 1.4 1.4 1.4 1.4 Extender, barium sulfate 9.2 9.3 9.5 9.2 9.4 Extender, mica 4.2 4.2 4.3 4.1 4.2 Extender, nepheline syenite 15.3 15.3 15.6 15.2 15.6 Ammonia 25% 0.1 0.1 0.1 0.3 0.1 Binder, alkyd emulsion (42 wt% solids) 46.2 46.4 47.3 46.0 47.2 Binder, alkyd emulsion (60 wt% solids) Metal drier 0.2 0.2 0.2 0.2 0.2 Surface wetting agent 0.3 0.3 0.3 0.3 0.3 Wax emulsion 2.4 2.4 2.5 2.4 2.5 Silicone additive 0.3 0.4 0.4 0.3 0.4 Colorant white 4.0 4.0 4.2 4.0 4.2 Colorant black 2.3 2.3 2.4 2.3 2.4 Associative thickener HASE 0.3 0.3 Associative thickener HEUR 2.6 2.1 Hydrophilic fumed silica Methyl hydroxyethyl cellulose thickener 0.4 Alkali-soluble emulsion acrylic thickener 1.1 Organically-modified hectorite clay 0.7 paint characteristics wt% solids 56.4 56.5 57.6 55.9 57.8 low shear viscosity [dPa.s] 89 51 11.1 12.9 11.3 wt% thickener (active agent(s)) 0.5 0.4 0.4 0.3 0.7 ratio associative thickener on total thickener composition 1 1 0 0 0 application performance length of conical spray (cm) too viscous to be applied too viscous to be applied 20 18 18 mist formation 3 1 1 levelling 4 3 5 hold-up 0 0 1

[0350] The results of Tables 1A and 1B show that aqueous coating compositions having a solids content of the composition in the range from 30 wt% to 65 wt%, exhibiting a viscosity value of at least 5 dPa.s and not exceeding 50 dPa.s and containing from 0.05 to 2.0 wt% based on the total weight of the composition of at least one organic or organically modified thickener where over 50 wt% is an associative thickener (based on the total weight of organic or organically modified thickener) showed good spray behaviour with limited mist formation and appropriate levelling and hold-up of the dried film. The insufficient hold-up of Comparative Example 3 demonstrates that the aqueous coating composition for application by the liquid spray apparatus should contain at least 0.05 wt% based on the total weight of the composition of at least one thickener.

[0351] dPa.s stands for decipascal seconds. 10 dPa.s equates to 1 Pa.s.

[0352] In Table 1 and in the other tables herein [0353] ‘Biocide’ is ACTICIDE MBS 5050 which contains 1,2-benzisothiazolin-3-one and 2-methyl-4-isothiazolin-3-one. It is available from Thor. [0354] ‘Organic solvent’ is propylene glycol. [0355] ‘Pigment wetting agent’ is DISPERBYK 190 which comprises a high molecular weight block copolymer with pigment affinic groups. It is available from Byk. [0356] ‘Defoamer’ is TEGO FOAMEX 810 which comprises polyether siloxane copolymer and fumed silica. It is available from Evonik. [0357] ‘Metal drier’ is BORCHERS OXY-COAT which comprises an active iron complex in propylene glycol. It is available from Borchers. [0358] ‘Surface wetting agent’ is SURFYNOL 104E which comprises tetramethyldec-5-yne-4,7-diol. It is available from Evonik. [0359] ‘Wax emulsion’ is AQUACER 513 which is a non-ionic emulsion based on an oxidized HD polyethylene wax. It is available from Byk.

TABLE-US-00003 COMPOSITION Example 1 Example 3 Example 4 Example 5 Comparative Example 9 Parts by Wt Parts by Wt Parts by Wt Parts by Wt Parts by Wt Water 9.4 21.1 33.1 43.8 55.1 Biocides 0.1 0.1 0.1 0.1 0.0 Organic solvents 0.5 0.4 0.3 0.3 0.2 Pigment wetting agents 1.3 1.1 1.0 0.8 0.6 Defoamer 1.4 1.2 1.0 0.8 0.6 Extender, barium sulfate 9.4 8.1 6.8 5.6 4.3 Extender, mica 4.2 3.7 3.0 2.5 1.9 Extender, nepheline syenite 15.5 13.4 11.2 9.2 7.1 Ammonia 25% 0.1 0.1 0.1 0.1 0.1 Binder, alkyd emulsion (42 wt% solids) 47.1 40.6 33.8 27.8 21.4 Metal drier 0.2 0.2 0.1 0.1 0.1 Surface wetting agent 0.3 0.2 0.2 0.2 0.1 Wax emulsion 2.5 2.1 1.8 1.5 1.1 Silicone additive 0.4 0.3 0.3 0.2 0.2 Colorant white 4.1 3.5 2.9 2.4 1.9 Colorant black 2.4 2.0 1.7 1.4 1.1 Associative thickener HASE 0.3 Associative thickener HEUR 0.8 1.8 2.6 3.4 4.2 paint characteristics wt% solids 57.1 50.0 42.0 34.8 27.0 low shear viscosity [dPa.s] 12.1 12.6 12.5 12.2 12.2 wt% thickener (active agent(s)) 0.2 0.3 0.5 0.6 0.8 ratio associative thickener on total thickener composition 1 1 1 1 1 application performance length of conical spray (cm) 13 18 19 18 27 mist formation 0 0 2 2 3 levelling 1 0 0 0 5 hold-up 1 0 0 0 0

[0360] Example 1 of Table 2 is physical repetition of Example 1 of Table 1A, to assess reproducibility. The example was re-formulated and re-tested, now with the examples of Table 2.

[0361] The test results as presented in Table 2 show that the solids content of an aqueous paint composition for application by the liquid spray assembly should be at least 30% (calculated as weight solids content) to avoid unacceptable mist formation and inadequate levelling.

TABLE-US-00004 COMPOSITION Example 1 Comparative Example 10 Comparative Example 11 Comparative Example 12 Comparative Example 13 Comparative Example 14 Parts by Wt Parts by Wt Parts by Wt Parts by Wt Parts by Wt Parts by Wt Water 9.4 9.4 9.4 9.5 9.5 9.5 Biocides 0.1 0.1 0.1 0.1 0.1 0.1 Organic solvents 0.5 0.5 0.5 0.5 0.5 0.5 Pigment wetting agents 1.3 1.3 1.3 1.3 1.3 1.3 Defoamer 1.4 1.4 1.4 1.4 1.4 1.4 Extender, barium sulfate 9.4 9.4 9.4 9.4 9.4 9.4 Extender, mica 4.2 4.2 4.2 4.2 4.2 4.2 Extender, nepheline syenite 15.5 15.5 15.5 15.6 15.6 15.6 Ammonia 25% 0.1 0.1 0.1 0.1 0.1 0.1 Binder, alkyd emulsion (42 wt% solids) 47.1 47.0 47.0 47.1 47.1 47.1 Metal drier 0.2 0.2 0.2 0.2 0.2 0.2 Surface wetting agent 0.3 0.3 0.3 0.3 0.3 0.3 Wax emulsion 2.5 2.5 2.5 2.5 2.5 2.5 Silicone additive 0.4 0.4 0.4 0.4 0.4 0.4 Colorant white 4.1 4.1 4.1 4.1 4.1 4.1 Colorant black 2.4 2.4 2.4 2.4 2.4 2.4 Associative thickener HASE 0.3 Associative thickener HEUR 0.8 1.0 0.8 0.7 0.6 0.3 Organically-modified hectorite clay 0.2 0.3 0.4 0.5 0.7 paint characteristics wt% solids 57.1 57.2 57.3 57.4 57.5 57.7 low shear viscosity [dPa.s] 12.1 12.2 11.8 11.9 12.1 12.2 wt% thickener (active agent(s)) 0.2 0.4 0.5 0.5 0.6 0.7 ratio associative thickener on total thickener composition 1 0.47 0.34 0.24 0.17 0.06 application performance length of conical spray (cm) 13 16 19 16 20 19 mist formation 0 0 0 0 0 0 levelling 1 4 4 4 5 5 hold-up 1 1 1 1 1 1

[0362] Example 1 of Table 3 is repetition of Example 1 of Table 1A and Table 2, to assess reproducibility. The example was re-formulated and re-tested, now with the examples of Table 3.

[0363] The test results of Table 3 show that the thickener in the aqueous paint composition for application by the liquid spray assembly should comprise at least 50 wt% (based on the total weight of thickener) of an associative thickener. A higher concentration of a non-associative organic or organically-modified thickener at the expensive of an associative thickener results in an unacceptable deterioration of the levelling performance.

TABLE-US-00005 COMPOSITION Example 6 Example 7 Comparative Example 15 Comparative Example 16 Comparative Example 17 Parts by Wt Parts by Wt Parts by Wt Parts by Wt Parts by Wt Water 12.0 37.3 12.1 14.0 12.0 Biocides 0.1 0.1 0.1 0.1 0.1 Organic solvents 0.5 0.4 0.5 0.5 0.5 Pigment wetting agents 1.8 1.2 1.8 1.7 1.8 Defoamer 3.5 2.4 3.5 3.4 3.5 Titanium dioxide 14.4 10.0 14.5 14.0 14.4 Extender, mica 3.1 2.2 3.2 3.1 3.2 Extender, nepheline syenite 13.2 9.1 13.3 12.9 13.2 Ammonia 25% 0.1 0.1 0.1 0.3 0.1 BINDER, ALKYD EMULSION (42 wt% solids) 46.5 32.2 46.8 45.3 46.6 Metal drier 0.2 0.1 0.2 0.2 0.2 Surface wetting agent 0.3 0.2 0.3 0.3 0.3 Wax emulsion 2.8 1.9 2.8 2.7 2.8 Silicone additive 0.4 0.3 0.4 0.4 0.4 Associative thickener HEUR 1.0 2.5 Methyl hydroxyethyl cellulose thickener 0.5 Alkali-soluble emulsion acrylic thickener 1.1 Organically-modified hectorite clay 0.9 paint characteristics wt% solids 56.3 39.3 56.9 55.0 57.1 low shear viscosity [dPa.s] 12.1 12.5 11.2 12.6 11 wt% thickener (active agent(s)) 0.20 0.48 0.49 0.32 0.93 ratio associative thickener on total thickener composition 1 1 0 0 0 application performance length of conical spray (cm) 18 11 18 17 18 overspray (cm) 6.5 7 6 >12 6.5 levelling 1 0 4 4 5 hold-up 0 0 0 0 2

[0364] Table 4 shows the test results of white pigmented aqueous paint compositions for application by the liquid spray assembly. As shown by the comparative Examples 15 - 17, the use of a non-associative thickener as sole rheology modifier leads to unacceptable levelling performances. The use of an alkali-soluble emulsion acrylic thickener leads to extensive overspray, necessitating substantial masking to avoid drift onto unintended objects.

TABLE-US-00006 Example 8 COMPOSITION Parts by Weight Water 15.0 Biocides 0.2 Organic solvents 5.9 Pigment wetting agents 1.7 Defoamer 1.1 Titanium dioxide 13.2 Extender, calcium carbonate 6.3 Hydrophilic fumed silica 1.0 Ammonia 25% 0.2 Binder, PU-modified acrylic dispersion (41 wt% solids) 51.6 Surface wetting agent 0.2 Wax emulsion 2.6 Silicone additive 0.4 Associative thickener HASE 0.5 Associative thickener HEUR 0.1 paint characteristics wt% solids 44.5 Haake viscosity [dPa.s] 21.7 wt% thickener (active agent(s)) 0.1 ratio associative thickener on total thickener composition 1 application performance length of conical spray (cm) 22 overspray (cm) 7 levelling 1 hold-up 1

Table 5 shows the use of a PU-modified acrylic binder and of an alternative HEUR associative thickener ACRYSOL RM-825.

[0365] In summary, exemplary embodiments of a liquid spray assembly and method of using a liquid spray assembly have been described. It is believed that the described exemplary embodiments describing a liquid spray assembly, being the combination of liquid spray apparatus and liquids have defined properties of solids content, thickener profile and viscosity offer improvements over known liquid spray apparatus and methods. The liquid spray assembly of the exemplary embodiments is convenient to manufacture and straightforward to use. Furthermore, the liquid spray assembly of the exemplary embodiments is easy to transport and accurate to apply a liquid to a surface to be coated by the liquid. Liquids having the characteristics described above have been shown to perform excellently.

[0366] The liquid spray assembly may be manufactured industrially. Industrial application of the example embodiments will be clear from the discussion herein.

[0367] It will be appreciated that the liquid may be a coating liquid. For example, the coating liquid may be a paint, a varnish, a stain etc. The coating liquid may comprise a decorative coating liquid, such as a decorative coating for masonry surfaces or for wood surfaces (such as use of a water based coating, or others, which may be applied directly onto such surfaces or overcoated onto existing coatings on such surfaces, for example). The coating liquid may include a protective coating, such as a protective coating which may be used on marine structures (such as marine platforms, for example) or on marine vessels (such as boats, for example), or on oil and gas processing structures.

[0368] Although exemplary embodiment of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made without departing from the scope of the invention as defined in the claims.

[0369] Capitalised names given herein for products are trade marks and may be Registered Trade Marks.

[0370] As used herein, unless otherwise expressly specified, all numbers such as those expressing values, ranges, amounts or percentages may be read as if prefaced by the word “about”, even if the term does not expressly appear. Also, the recitation of numerical ranges by endpoints includes all integer numbers and, where appropriate, fractions subsumed within that range (e.g. 1 to 5 can include 1, 2, 3, 4 when referring to, for example, a number of elements, and can also include 1.5, 2, 2.75 and 3.80, when referring to, for example, measurements). The recitation of end points also includes the end point values themselves (e.g. from 1.0 to 5.0 includes both 1.0 and 5.0). Any numerical range recited herein is intended to include all sub-ranges subsumed therein.

[0371] Singular encompasses plural and vice versa. For example, although reference is made herein to “a cartridge”, “a nozzle”, “a thickener” and the like, one or more of each of these and any other components can be used.

[0372] As used herein, the term “polymer” refers to oligomers and both homopolymers and copolymers, and the prefix “poly” refers to two or more.

[0373] The terms “comprising”, “comprises” and “comprised of” as used herein are synonymous with “including”, “includes” or “containing”, “contains”, and are inclusive or open-ended and do not exclude additional, non-recited members, elements or method steps. Additionally, although the present invention has been described in terms of “comprising”, the coating liquids detailed herein may also be described as “consisting essentially of” or “consisting of”.

[0374] As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself or any combination of two or more of the listed items can be employed. For example, if a list is described as comprising group A, B, and/or C, the list can comprise A alone; B alone; C alone; A and B in combination; A and C in combination, B and C in combination; or A, B, and C in combination.