GB2353828A - A detergent liquid dispensing container - Google Patents

Abstract

A detergent liquid dispensing container comprising an outlet nozzle 4 with a valve or pump assembly 3 and an elongate flexible conduit or dip-tube 5 having a first end in communication with the outlet nozzle 4 and, distal from the first end, a second end that defines a liquid inlet. The dip-tube 5 is formed of a hydrophobic plastics material and has a reservoir 8 disposed at the second end. The liquid inlet is an aperture 7 in the reservoir 8 having a diameter between 0.25 mm and 7mm, and preferably between 1 mm and 3 mm. The reservoir provides a temporary supply of liquid 2 that can be dispensed with the container in an inverted position, and the inlet 7 is sized so that detergent liquids do not fall out of the reservoir during inversion of the container. The inlet aperture 11 may alternatively be formed in a recessed end of the reservoir 10, enabling retention of liquid through capillary action in the in-turned inlet 11, and in an annular cavity 12 formed by the recess.

Description

2353828 A DETERGENT LIQUID DISPENSING CONTAINER The present invention

relates to a detergent liquid dispensing container and more particularly, but not exclusively, to such a container that is hand-held and is operable to activate a pump action mechanism or pressurised gas propellant to dispense a detergent liquid through a nozzle.

A wide variety of liquid products are packaged in hand-held containers of the type described above. In the market sector of cleaning and personal care products (e.g. toiletries and cosmetics) such containers are generally disposable and are therefore constructed from relatively simple and few components as mass production and low cost are over-riding factors. The use of moving parts is undesirable as this increases the number of components, the assembly time and the risk of malfunction in use.

When it is required to dispense a fluid in the form of a spray such dispensers often have a flexible conduit known as a "dip-tube" that extends from a dispensing nozzle towards the bottom of the container where the fluid to be dispensed is situated. In order to ensure that fluid is dispensed the inlet end of the dip-tube is immersed in the fluid in the container. In use, the fluid to be dispensed passes up the dip- tube under pressure and out through the nozzle. The dip-tube enables fluid to be dispensed even when the pump or other release mechanism is disposed above the level of fluid in the container. This arrangement has a significant disadvantage in that dispensing of the fluid is not possible when the container is not in the upright or substantially upright position. This is because inversion of the container or tilting of the container when the fluid level is low results in the fluid moving clear of the inlet end of. the dip-tube.

It is known to attach a weight to the end of a flexible dip-tube so that when the container is inverted the inlet end of the dip-tube is moved under gravity with the fluid thereby ensuring virtually constant immersion of the dip-tube in the fluid to be dispensed. Examples of such an arrangement are shown GB-A-902114. GB-A1008733, GB-A-2136057, GB-A2217394, GB-A-2234555 and EP-A-0285040. Such designs have several disadvantages. First, the container should be sufficiently large in all axes to enable the dip-tube to loop back on itself irrespective of the direction of tilt or inversion. However, this requirement is at odds with the need for the container to 2 be of a size that is suitable for hand-held operation. Secondly, extra design features have to be incorporated to prevent kinking of the dip- tube and therefore interruption to the delivery of the fluid. For example, the dip-tube may be manufactured from a material with high flexibility (i.e. in excess of that offered by the commonly used conunercial polymers) or may be formed with a particular configuration such as a spiral (an example is shown in EP-A-0592082). Such design measures increase the manufacturing cost of the dispenser. Thirdly, the attachment of a weight is not suitable to high speed mass production in which one- piece mouldings are preferred.

US-A-5341967 describes a trigger spray dispenser that has the capacity to operate in both upright and inverted positions. The dispenser has a diptube that is provided with a by-pass chamber and associated valve mechanism. In addition to the relative complexity and the increased number of components in this design it has the drawback that the valve mechanism does not operate when the container is in the horizontal plane and consequently the liquid may not be dispensed.

AU-B-660764 describes a liquid dispensing container that is able to operate effectively in the inverted configuration. The outlet nozzle of the container is fitted externally with a vertically extending conduit and intemally with a specially adapted valve assembly including a gravityoperated check valve. This is a relatively complex solution with many moving parts. In an alternative configuration the dip-tube is fitted with a terminal reservoir. When a pump is operated to dispense liquid in the upright position liquid is drawn into the reservoir. Subsequently, upon inversion of the container liquid stored in the reservoir can still be dispensed even though the remainder of the liquid in the container is below the end of the dip-tube. However, in practice this arrangement suffers from the tendency of liquid to fall out of the reservoir inlet during inversion of the container.

In order for devices such as that disclosed in AU-B-660764 to function effectively, they require careful specification of their engineering parameters for actual application. Such parameters may be supposed to be amenable to calculation by one skilled in the art, however, in practice this is rarely possible outside well defined fluids with defined behaviours, for example water. In particular, detergent liquid

3 compositions requiring dispensing from containers are particularly troublesome as they display a variety of interrelated non-linear behaviours.

In the case of a device without a reservoir at the end of the dip-tube, the liquid stays within the tube on inversion owing to capillary action. This is not possible with a large reservoir at the end of the tube. The contact angles of liquid droplets (both advancing and receding contact angles) to the surface of the dip-tube determines whether the liquid stays within the reservoir, the contact angles being dependent upon the liquid composition and the material of construction of the dip-tube. The contact angles are in turn related to the surface tension, particularly the dynamic surface tension of the particular detergent composition. In addition viscoelastic, rheopectic, shear thinning and Marengony flow characteristics play a role in many thickened compositions as these give rise to various desirable in use characteristics. It has therefore proved difficult to manufacture successfully a dip-tube including a reservoir to enable use in an inverted position with detergent compositions.

It is an object of the present invention to obviate or mitigate the aforesaid disadvantages.

According to the present invention there is provided a detergent liquid dispensing container comprising an outlet nozzle with a valve or pump assembly and an elongate conduit having a first end in communication with the outlet nozzle and, distal from the first end, a second end that defines a liquid inlet, characterised in that the conduit is formed of a hydrophobic plastics material and has a reservoir disposed at the second end, the liquid inlet being an aperture in the reservoir having a diameter between 0.25 mm and 7min.

It has been found from tests conducted on reservoirs provided at the end of conduits used in fluid dispensing containers, that there is a range of aperture sizes that provide beneficial results in that the aperture is small enough to prevent emptying of the reservoir on inversion of the container but is sufficiently large to allow unrestricted operation of the dispensing container whilst the container remains inverted. The use of a dip-tube having an inlet of a predetermined size and a reservoir at the end of the tube means that the container may be operated in the inverted 4 position, and that the dip-tube is simple to manufacture as it may be formed of one piece of plastics material.

The conduit is preferably flexible. Preferably the inlet aperture has a diameter between 0.5 mm and 5 min, and more preferably between 1 min and 3 min.

The best results are achieved when the detergent liquid has a surface tension of less than 60 mN/m, preferably less than 20 mN/m, and most preferably less than 2.5 mN/m.

The inlet aperture may be recessed into the reservoir by virtue of, for example, an in-tumed end. This means that liquid is retained by the aperture owing to capillary action, and also that some liquid is trapped in the reservoir beneath the level of the aperture, and cannot escape from the reservoir on inversion of the container.

The container may be an aerosol container that is pressurised by a propellant fluid and the outlet nozzle is associated with a valve. The nozzle may form part of an actuator that is manually operable to open said valve so as to dispense liquid through the nozzle.

Alternatively, a manually operable actuator may be provided that contains said nozzle and which is operable to operate said pump assembly so as to dispense liquid through the outlet nozzle.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a diagrammatic representation of a dip-tube for use in a container in accordance with the present invention; Figure 2 is a diagrammatic representation of a container in accordance with the present invention in an upright orientation; Figure 3 is the container of figure 2 shown inverted; and Figure 4 is a diagrammatic representation of an alternative embodiment of reservoir for use in the present invention.

Referring now to figures 1, 2 and 3 of the drawings, the exemplary container has a main chamber 1 for retaining liquid 2 and an external dispensing actuator 3 with outlet nozzle 4 of conventional design.

An elongate flexible conduit 5 extends from the actuator 3 towards a base 6 of the main chamber I and terminates in an inlet 7 that, in use, is immersed in the liquid 2 in the chamber. Such a conduit 5 is conventionally known as a "dip-tube". At the inlet end of dip-tube 5, the dip-tube is of increased diameter and forms a liquid reservoir 8.

The dip-tube 5 is constructed of a hydrophobic plastics material. Any suitable material may be used, although those derived from vinyl monomers with a range of hydrophobicites, copolymers and homopolymers with a variety of end groups are particularly suitable. Examples include ethylene, propylene, butylene and other alkenic derivatives, vinylidene chloride derivatives and polyester derivatives. Cellullosic derivatives such as cellophane, methylated celluloses and polyamides (e.g. Nylon 6.6) are other possibilities. High or low-density polyethylene and polypropylene are particularly suitable materials in view of the fact that they impart both a water vapour barrier and strength and are strongly hydrophobic. In order to provide flexibility to the dip-tube plasticisers are typically added to the polymer, as may opacifiers and metallised coatings as required.

The main chamber 1 is filled with liquid 2 to be dispensed and may be pressurised with a propellant fluid such as that used in conventional aerosol dispensers (e.g. air, nitrogen, argon or another noble gas, carbon dioxide, butane, volatile hydrocarbons, fluorocarbons, chlorocarbons or chlorofluorocarbons). In such a design depression of the actuator 3 opens a valve (not shown) and the pressurised fluid in the chamber I forces the liquid 2 up the dip-tube 5 to the outlet nozzle 4 from which it is propelled in the form of a spray (shown in broken line). Alternatively, the nozzle 4 is connected to a known pump assembly so that repeated depression of the actuator 3 increases the internal pressure of the chamber i and forces liquid 2 up the dip-tube 5 and out of the nozzle 4 in a spray. Pump assemblies of this kind are known from trigger-spray actuators (one example is described in US 5341967).

When liquid 2 passes up the dip-tube 5 in the manner described above it first has to fill the reservoir 8 before it reaches the outlet nozzle 4. It is the filling of this reservoir 8 that allows the container to function in an inverted position.

6 As shown in figure 3, when the container is inverted the liquid 2 in the container falls below the inlet 7 of the dip-tube 5 and cannot therefore be dispensed whilst the container remains inverted. However, there is still sufficient liquid 2a in the diptube 5 and reservoir 8 to permit several discharges of liquid from the nozzle 4. The amount of liquid 2 that can be discharged without moving the container back to the upright position and recharging the dip-tube 5 is obviously dependent on the capacity of the reservoir 8. It should be noted that discharging the liquid becomes harder whilst the container is inverted, as air cannot enter the chamber to replace the liquid that has been discharged. This means that each spraying action whilst the container is inverted must be performed against an increasing internal pressure in the chamber.

When the reservoir 8 contains liquid it acts as a weight such that during tilting of the container the dip-tube 5 flexes and the reservoir remains in contact with the liquid in the container.

The process of inversion of the container of the present invention does not allow escape of a significant amount of liquid due to the size of the inlet 7. The inlet size is partly dependent on the type of detergent composition, and the estimation of its size is illustrated by the following non-limiting examples:

Detergent test coMpositions 1 to 6 Each solution (1 to 6) was prepared by adding 0.1% of the specified surfactants (see table 1 below) to demineralised water. Agrimul (registered trade mark) surfactants are obtainable from Henkel. Solutions with higher viscosity were obtained by dispersing the polymeric thickener Polygel DR (ex 3V Sigma) at various levels in dernineralised water so as to obtain the viscosity stated at 10 s1 shear rate, measured using a Haake RV20 rotvisco viscometer equipped with an MV parallel cylinder flow cup. This was achieved by diluting a pre-made solution of 0.4% polygel, buffered to pH 8 with sodium hydroxide, until the desired viscosity was achieved after equilibration of the sample. Any surfactant was subsequently added. The shear rate was chosen as a convenient figure for experimental purposes, a shear rate of 1 s' 7 being taken as indicative of the shear rate associated with movement of the liquid in the bottle on inversion and a shear rate of 400 s' being taken as indicative of spraying such a liquid, i.e. in a region where no residual shear sensitivity is obtained. Surface tension was measured using a Kruss spinning drop interfacial tensiometer. All the tests were performed at ambient temperature (18T) with the viscosity and interfacial tension being measured at 25'C.

8 Table 1

Detergent test Surfactant Polymer added composition 1 Agrimul PG none 2062 2 Agrimul PG none 2069 3 Agrimul PG none 2076 4 None to SOmPa.s @10 S-' None to 20OmPa.s @10 S 6 Agrimul PG to 50mPa.s 2062 @10 S-, Water None ImPa.s Comparative (Newtonian) Table 2 - Detergent test coLnposition 7 Components ww% Alkyl benzene sulphonic acid 0.4 Sodium Hydroxide 0.1 Alcohol ethoxylate (C9-11, 8E0) 2.9 Formalin 0.5 Hydroxy ethyl cellulose 0.5 Industrial Methylated Spirit 0.5% Dye 0.0026% Tartrazine 0.0036% Fragrance 0.55% to 100% 9 Table 3 - Data for detergent test compositions Sample Surface tension Viscosity @ 0.1 S Viscosity @ 400 s' mPa.s m.Pa.s 1 2.9 mNIm -ImPa.s -IrnPa.s 2 1.6 mN/m -ImPa.s -lmPa.s 3 0.8 mN/m -ImPa.s -ImPa.s 4 56 mN/m 20OmPa.s 48mPa.s 54 mN/m 715mPa.s 194mPa.s 6 3.0 mN/m 20OmPa.s 48mPa.s Water 72 mN/m ImPa.s ImPa.s Comparative This data quantifies one of the effects of the surfactant, surface tension and the shear thinning nature of the polymer.

Loss of liquid on inversion versus gperture size - Emplying test Emptying tests were carried out on a dip-tube formed of polyethylene, with the configuration shown in Figure 1 and having dimensions of- dip- tube = 4mm diameter; length of reservoir =3cm; inlet diameter = as in table 4; and radius of curvature R of end of reservoir = 1cm, the dip- tube having a circular cross section. The dip-tube (i.e. reservoir and associated tube) was filled with the liquid, the total weight of liquid being known. The dip-tube was then sealed at the top end, lifted until the bottom of the reservoir was just level with the liquid surface and then rotated vertically through 180' at a constant rate so that the reservoir was positioned above the dip-tube, the rotation taking 10 seconds. The tube was then removed and weighed. The difference in weight corresponds to the liquid lost on inversion and hence that unavailable for an inverted spray operation. The liquid lost by the dip-tube was expressed (see table 4) as a percentage of the liquid initially present in the dip-tube.

Table 4

Test detergent Aperture size (mm) 0.5 1 3 5 6 7 8 10 12 1 <10% <10% <10% 20% 65% 75% >9TIO >90% >90% 2 <10% <10% <10% 25% 80% >90% >90% >90% >90% 3 <10% <10% <10% 25% 80% >90% >90% >90% >90% Water <10% <10% <10% <10% <10% <10% <10% >90% >90% Comparative 4 <10% <10% <10% <10% <10% <10% <10% 80% >90% <10% <10% <10% <10% <10% <10% <10% <10% 65% 6 <10% <10% <10% <10% <10% <10% 75% >90% >90% 7 <10% <10% <10% <10% <10% <10% <10% <10% 55% All data is an average of three tests rounded to the nearest 5%.

The data in table 4 shows that the presence of surfactant increases the amount of leakage of liquid from the dip-tube at a particular aperture size. Whilst a polymer added to the liquid mitigates these effects, the surfactant effect is still present. The optimum aperture size is thus less than 7mm, preferably less than 5mrn and more preferably less than 3mm. It is surprising that such an aperture size is beneficial regardless of the size of the reservoir.

The best results are achieved when the detergent liquid has a surface tension of less than 60 mN/m, preferably less than 20 m.N/m, and most preferably less than 2.5 mN/m Filling test The dip-tube was associated with a Guala (UK) hand-held trigger spray mechanism 9C (e.g. as used in a window cleaner type product). The spray dispenses liquid by positive pressure and refills the 0.7ml reservoir by suction. The spray was actuated at three sprays per second using a dip- tube of polyethylene, as in Figure 1, having dimensions of. dip-tube = 4mm diameter; length of reservoir = 3cm; inlet diameter = as in table 4; and radius of curvature R of end of reservoir = Icm, the diptube having a circular cross section.

The specified dip-tube (as above) was used with test detergent 7 (see table 5). The number of sprays executed until such ti-tne as the spray rate could no longer be sustained owing to prolonged filling time (i.e. after the reservoir had collapsed owing to the increased pressure in the main chamber) was noted.

Filling Test with Test coMosition 7 The number of liquid spr ays each of 0.7mI that could be executed before the spray rate could no longer be sustained (or if a reduction in spray rate was not applicable) are shown in table 5 below.

Table 5

Test Aperture size (mm) composition 0.12 0.25 0.5 1 1.5 2 3 4 5 6 3 5 8 N/A N/A N/A N/A N/A N/A 7 3 3 5 7 N/A N/A N/A N/A N/A Water 7 N/A N/A N/A N/A N/A N/A N/A N/A Comparative The data in table 5 shows that the lower limit of aperture size to allow for successful spraying during inversion for the detergent composition is 0.25mm, more preferably O.Snun, and most preferably Imm.

Referring now to Figure 4 of the accompanying drawings, an alternative form of dip-tube is illustrated.

The dip-tube 9 includes an increased diameter reservoir 10 at one end thereof The reservoir 10 has a recessed end so that an aperture 11 forming an inlet to the diptube is in-turned and is placed inwardly of the end of the dip-tube. This design of reservoir retains some liquid due to capillary action in the in-turned inlet, in addition to the inlet size being pre-determined. Moreover some liquid is retained in an annular 12 cavity 12 defined by the in-turned end so that it is available for expulsion through the nozzle upon inversion of the container.

It will be appreciated that numerous modifications to the above-described design may be made without departing from the scope of the invention as defined in the appended claims. For example, the reservoir can take any suitable form other than that depicted in the appending figures the important aspect being that it makes available to the outlet nozzle a larger volume of fluid as compared to a dip tube of constant crosssection. Moreover, the dip-tube may not necessarily be flexible.

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Claims (12)

1. A detergent liquid dispensing container comprising an outlet nozzle with a valve or pump assembly and an elongate flexible conduit having a first end in communication with the outlet nozzle and, distal from the first end, a second end that defines a liquid inlet, characterised in that the conduit is formed of a hydrophobic plastics material and has a reservoir disposed at the second end, the liquid inlet being an aperture in the reservoir having a diameter between 0.25 mm and 7mm.

2. A detergent liquid dispensing container according to claim 1, wherein the conduit is flexible.

3. A detergent liquid dispensing container according to claim 1 or 2, wherein the inlet aperture has a diameter. between 0. 5 mm and 5 mm.

4. A detergent liquid dispensing container according to claim 3, wherein the inlet aperture has a diameter between 1 mm and 3 mm.

5. A detergent liquid dispensing container according to any preceding claim, wherein in use the surface tension of the detergent liquid is less than 60 mN/m

6. A detergent liquid dispensing container according to claim 5, wherein in use the surface tension of the detergent liquid is less than 20 mN/m.

7. A detergent liquid dispensing container according to claim 6, wherein in use the surface tension of the detergent liquid is less than 2.5 mN/m.

8. A detergent liquid dispensing container according to any preceding claim, wherein the inlet aperture is recessed into the reservoir.

9. A detergent liquid dispensing container according to any preceding claim, wherein the container is an aerosol container that is pressurised by a propellant fluid and the outlet nozzle is associated with a valve.

10. A detergent liquid dispensing container according to claim 9, wherein the nozzle forms part of an actuator that is manually operable to open said valve so as to dispense liquid through the nozzle.

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11. A detergent liquid dispensing container according to any of claims 1 to 8, wherein there is provided a manually operable actuator that contains said nozzle and which is operable to operate said pump assembly so as to dispense liquid through the outlet nozzle.

12. A detergent liquid dispensing container substantially as hereinbefore described with reference to figures 1 to 3 or figure 4 of the accompanying drawings.