GB2038954A - Pressurised Aerosol Dispensers - Google Patents

Abstract

An aerosol dispensing device for a pressurized container containing a liquid product composition in a lower product layer, an intermediate liquid propellant layer and an upper vapor propellant layer, comprises valve and diptube means adapted to draw off simultaneously product and liquid propellant to said valve means, said diptube means extending to a point near the bottom of said container, and comprising means permeable only to said liquid propellant and means impermeable to said product and vapor propellant and being open to said product layer. The diptube means may comprise separate dip tubes either side-by-side as shown, or concentric tubes. The tube 13 is open and impermeable to the product and the tube 19 is impermeable to the product but permeable to the liquid propellant. Liquid from the two tubes mix in the valve 6 which may also have a vapour tap 18. Alternatively the diptube means may comprise a single tube of composite construction. <IMAGE>

Description

SPECIFICATION Aerosol Dispensing System The present invention relates to a pressurized aerosol device using a hydrocarbon propellant to dispense a composition which is not soluble or miscible in the hydrocarbon as a fine, dry spray at a uniform rate. More particularly, the invention relates to a novel aerosol valve/diptube assembly for dispensing a water-based hair spray concentrate with a hydrocarbon vapor/liquid propellant.

Background of the Invention It is known to dispense fluids from pressure containers under the propelling action of a gas or other propellant within the container and, more particularly, to dispense from a single container simultaneously a mixture of two immiscible liquids which form in the container two or more separate and non-interspersed layers.

As will be understood, a wide variety of materials may be dispensed from pressurized containers under the action of gaseous or vaporized propellant therein as with the so-called aerosol types of packaging. Generally in situations of this character, the material to be dispensed is admixed with a propellant (gas or highly volatile liquid, etc.) in a sealed container having a valved eduction tube whereby opening the valve provides for the propellant to force the material to be dispensed up the eduction tube and out of the container. Such a system is called a two phase system, phase I being an upper layer of vaporized propellant, and phase 11 being a mixture of liquid propellant and product to be dispensed.

If however, the particular materials to be dispensed are in the nature of immiscible liquids (one of which may be the propellant) which form separate or distinct and non-interspersed layers within the container, difficulty may be experienced in obtaining a simultaneous dispensing of both layers and/or a desirably homogeneous mixture thereof, especially if the immiscible materials are such as to resist interspersion or admixture by shaking or otherwise immediately prior to opening the dispensing valve. This is called a three phase system in which phase I is the upper layer of vaporized propellant, phase II is an intermediate layer of liquid propellant, and phase Ill is the lower layer of product.

Traditionally, an aerosol valve is fitted with a diptube, extending into the product to be dispensed, through which the product flows into the valve body and through the stem and button.

A vapor tap, which usually opens into the body of the valve, allowing propellant vapor to mix with the product stream, may be included in the device.

Hydrocarbons, for example, when mixed with a water-based product, tend to float on the surface thereof, since the two phases are immiscible.

Technology is available to formulate hair spray concentrates or antiperspirants, and so forth, using water as a solvent. Heretofore, the difficulty with such systems has been dispensing them as aerosol sprays using conventional aerosol valves, which do not provide sufficient break up of the product concentrate, resulting in streaming rather than misting. Recent technology has shown that such products can be dispensed by making use of the hydrocarbon vapor. This has not been satisfactory, since spray rates are low, possibly because of the fact that the vapor may occupy most of the volume of the body of the valve.

According to this invention, however, apparatus is provided for dispensing from aerosel containers simultaneously and with predetermined proportioning separate and immiscible materials forming in the container two or more distinct separate layers, and in a manner whereby the simultaneous dispensing from all layers and the predetermined proportioning thereof is maintained for the entire capacity of the container and regardless of the changing levels of liquid therein. Generally, in accordance herewith, separate or individual eduction tubes are provided for each of the several distinct and immiscible layers with that for the liquid hydrocarbon being permeable to the hydrocarbon, but not to the product to be dispensed or a single open ended tube permeable to the hydrocarbon may be used.

The present invention provides an aerosol valve/diptube assembly suitable e.g. for dispensing water-based products, using a hydrocarbon propellant, which can be formulated as a uniform, nonflammable spray.

Such products may be, for example hair sprays, antiperspirants, deodorants, shaving creams, space deodorizers, bathroom cleaners, aerosol paints, and the like.

The aerosol/diptube assembly of the present invention is best understood by reference to the accompanying diagram-Three Pase Aerosol System.

In this system use is made of the liquid hydrocarbon propellant (phase II). A propellant tap is provided, in addition to an optional vapor tap, wherein the liquid propellant is drawn into the body of the valve and mixes with the concentrate. The propellant tap is a tube which is permeable to the liquid propellant, but not the product composition. The intimate mixing of phase II (liquid propellant) and phase Ill (liquid concentrate) is done within the housing.

Brief Description of the Drawings The invention may be better understood by reference to the drawings in which: Fig. 1 is a side sectional diagrammatic view of a prior art pressurized package showing a two phase product/propellant system.

Fig. 2 is a side sectional diagramatic view of a prior art pressurized package showing a three phase product/propellant system.

Figs. 3 to 7 are alternative constructions for the valve and diptube assembly of the present invention.

Accordingly, it is an object of the invention to provide an improved aerosol pressured package containing a three phase propellant and product system.

A further object is to provide such a package which will dispense in a uniform fine mist spray a product that is not soluble or miscible with the propellant.

Another object is to provide a pressurized aerosol package which will dispense a uniform fine spray of a water based product using a hydrocarbon propellant.

These and other objects of the invention will become apparent as the description thereof proceeds.

Detailed Description of the Invention and Drawings Referring to Fig. 1, a conventional two phase aerosol system is shown having container 1 with body 2, bottom 3, collar 4 and top 5. A valve member 6 fits into top 5. The contents of container 1 are divided into two phases, an upper phase I and a lower phase 11. Phase II consists of a liquid propellant which is a vapor under atmosphere pressure and in which the product to be dispensed is dissolved or admixed. Phase I is vaporized propellant. Valve member 6 comprises a hollow stem with the valve 8 normally seated against gasket 9 by means of spring 1 0.

Surrounding the valve is a housing 11 with a tailpiece 12 to which flexible diptube 1 3 is attached.The valve stem 7 has actuator or head 14 mounted thereon with passageway 1 5 therethrough. When actuated by pressing down head 14, the valve 8 is moved downward to open into interior cavity 16 of valve body 11. Since vapor phase I and liquid phase Il are under superatmospheric pressure, fluid is forced up to diptube 13 into passageway 1 5. The liquid becomes vaporized and leaves head orifice 1 7 as a fine spray.

In Fig. 2, a conventional aerosol container 1 of the same type as Fig. 1 is shown having a three phase system, in which for example, phase I is vaporized propellant, phase Il is liquified propellant and phase Ill is a liquid product not miscible with the propellant and which is heavier than the liquid propellant. For example, the propellant may be a hydrocarbon, e.g. butane and the product phase may be a water-based hair spray. When actuator head 14 is depressed, phase Ill liquid rises up tube 13 into valve 6, but leaves orifice 1 7 as a stream or poorly dispersed spray rather than a fine mist since there is no vaporizable propellant admixed with it.In order to form a better mist spray, a tap 18 on valve body 11 has been added to admit vapor phase I to the body cavity 1 6 where it admixes with product liquid phase Ill giving a more mist-like spray from orifice 1 7. Such a system, however, has the disadvantage of an extremely low spray rate since the vapor occupies most of the volume of the valve body.

We have now found that this disadvantage may be overcome by the use of the valve assembly shown in Figs. 3 to 7. In the present device, the high spray rates and desired spray characteristics are obtained by mixing the liquid phase ll with the product phase Ill which are mixed in the housing of the valve and dispensed in the same ratio as they are charged into the can.

It has been proposed to admix a liquified phase with a non-miscible phase in the prior art such as in U.S. Patent Nos. 3,113,6983,260,421; or 3,272,402.

The problems encountered with these systems were that they were complex and expensive. Our inventive valve system accomplishes the admixing of phases ll and Ill by a different principle and by means of a much simpler device.

In Fig. 3 is illustrated an example of a valve and diptube assembly of the present invention.

In addition to all the conventional parts, as in the valve of Fig. 2, this new valve will have an additional diptube 1 9 which fits on housing 11 at a second tailpiece 20. Diptube 19, closed at the lower end extends to the bottom of container 1.

The purpose of this second diptube 1 9 is to draw liquid phase Il into the valve body. Its material of construction is such that it will not allow vapor phase I to permeate through and would preferentially allow liquid phase II to travel through the tube. A silidone treated filter paper can be used. When actuator head 1 5 of aerosol valve 6 is depressed, the liquid phase II, e.g. a hydrocarbon such as butane travels through permeable tube 19 while the product phase Ill, e.g. a water-based concentrate goes up the conventional tube 13 which is open at its lower end 21. The phases II and Ill mix within housing 11 and discharge through the head orifice 1 7.

As the product is used up, the vapor phase area I, increases. However, since tube 1 9 does not allow gaseous phase I to pass through, it does not affect the relative use up of the two liquid phases II and Ill. This results in a fine uniform spray which remains constant throughout the life of the can. A vapor tap 18 can be added optionally to admit phase I vapor to aid in draining phases Il and Ill when the unit is not operating. This draining is desirable for optimum performance so that a burst of liquid propellant is not obtained at any time. The function described above is unlike the use of conventional vapor tap described in the prior art when the vapor is admitted to enhance mixing. Tube 19 may also be a borosilicate glass filter tube (Balstron Filter Products). This consists of borosilicate glass fibers bonded together with a fluorocarbon cement.

An alternative construction is shown in Fig. 4.

Valve body 6 has a tailpiece 12 and diptube 13. A metal tube 22 having a plurality of perforations 23 is fitted to valve body 11 and surrounds diptube 1 3. Tube 22 is closed at its lower end by means impermeable to both phases Il and Ill, such as a stopper 24 through which diptube 13 extends, opening into phase Ill. Tube 22 is wrapped with a material 25 which is permeable to phase II but not phase Ill, such as a silicone treated filter paper and communicates with valve 6 through propellant tap orifice 20. Actuation of head 1 5 causes phase Ill liquid product to enter orifice 21 to diptube 13 and travel upward to valve 6.Phase Il liquid propellant permeates layer 25 and passes through perforations 23 into the interior of tube 22 travelling upward to propellant orifice 20 where it enters the body and admixes with phase Ill.

In Fig. 5, a single diptube 19 permeable only to liquid phase II and open at the lower end is attached to tailpiece 12 of valve 6. In this embodiment, the fluid phase Ill enters the tube through opening 26 at the lower end of tube 19, while liquid propellant phase II permeates the tube walls, both phases admixing in tube 19 and also within valve 6.

The permeable diptube may be a poromeric plastic, such as polystyrene, polyethylene, polypropylene, nylon, polycarbonates, teflon, polyvinylchloride. These poromeric materials are characterized by having multidirectional pores throughout the plastic mass. The pore size may vary from about 0.1 to 30 microns and larger and the pore density, the measure of pores per unit area, typically may be 70 percent, but may be lower or higher. The pore size desired will be dependent on a number of factors such as the internal diameter of the tube, the viscosity of the fluid concentrate. In one particular application a tube having an internal diameter of 1/16 inch was used with a hair spray concentrate having a viscosity of about 7 centistokes. In this instance, the desired pore size is from 1 to 5 microns and the pore density is from about 50 to 70 percent.

The poromeric tube may be prepared by a number of different methods.

In one method, the tube is made by casting of a polymer solution. A solution of polymer in which the compatibility of the solute and solvent is highly temperature dependent is cast or extruded. The solvent separates from the solute to form globules suspended in a polymer-solvent matrix. Removal of the solvent yields a porous material. Pore size is determined by the solution behavior of the components used and the rate of cooling of the solution and ranges from .1 microns to 11 microns.

In another method, the tube is made by sintering of plastic beads in molds. Beads of plastic are rounded (made spherical) and sorted for size. The pore size is determined by the bead size and typically ranges from 10 microns to 30 microns and larger with normal techniques but can be made down to .2 microns with special techniques.

A third method for making the diptube is by extrusion of a plastic with starch or salt suspended within. The starch or salt is removed by extraction in a hot bath. The starch requires hydrolysis to sugar by including acid in the extraction process. The size of the pores produced is dependent on the size of the salt or starch particles used and ranges from 10 microns downward. A pore density of 70 percent is obtained.

In Fig. 6, a single diptube 27 is provided which is open at the bottom 28 and has one side 29 impermeable to phase II and phase Ill and side 30 permeable to phase II but impermeable to phase Ill. The liquid product phase Ill enters tube 27 through orifice 28, and liquid propellant phase II enters the tube through permeable wall 30 of the tube.

Fig. 7 is similar to the embodiment of Fig. 6 except that the diptube 31 consists of alternating spiral bands of a material 32 which is permeable to phase II and material 33 not permeable to either phase Il or Ill. Phase Ill enters through the open end 34 of tube 31, and phase Ii propellant enters through material 32.

Following the Examples of formulations which may be dispensed in the inventive container and valve assembly of the present invention.

Example I Insecticide % w/w Pyrethrins 0.25 Piperonyl Butoxide 1.25 Fragrance 0.20 Petroleum Distillate 1.25 Deionized Water 67.05 Isobutane 30.00 100.00 Example II Space Deodorant Perfume 1.50 Deionized Water 73.50 Isobutane 25.00 100.00 Example III Antiperspirant Aluminum Chlorhydrol % w/w (Water soluble) 1 5.00 Perfume 0.50 Deionized Water 44.50 Isobutane 25.00 Alcohol 190 Proof 15.00 100.00 Example IV Deodorant Alcohol 190 Proof 20.00 Perfume 1.50 Deionized Water 53.50 Isobutane 25.00 100.00 Example V Hair Spray Alcohol 1 90 Proof 43.72 Gantrez ES 225 6.00 A.M.P. 0.13 Deionized Water 25.00 Perfume 0.15 Isobutane 25.00 100.00

Claims (8)

Claims

1. Valve and diptube means for a pressurized container containing a liquid product composition and propellant therein in a lower product layer, an intermediate liquid propellant layer and an upper vapor propellant layer, said valve and diptube means being adapted to draw off simultaneously product and liquid propellant to said valve means, said diptube means extending to a point near the bottom of said container, and comprising means permeable only to said liquid propellant and means impermeable to said product and vapor propellant and being open to said product layer.

2. Valve and diptube means as in Claim 1 wherein said permeable means is a diptube permeable only to said liquid propellant and connected to an orifice in said valve means and closed at its lower end; and said means impermeable to product and vapor propellant is a diptube connected to second orifice in said valve and is open at its lower end.

3. A valve and diptube means as in claim 1 wherein said permeable means is a permeable sleeve surrounding an impermeable diptube, said impermeable diptube connecting with said valve means and opening to said valve means and being open at its lower end, and said permeable sleeve being closed at its lower end, said valve means having an opening into the area within said impermeable diptube.

4. A valve and diptube means as in claim 1 wherein the diptube is a single tube connected to an orifice in said valve means and open at its lower end, at least a part of said diptube wall being permeable to said liquid propellant.

5. A valve and diptube means as in claim 1 wherein the diptube is a single tube connected to an orifice in said valve means and open at its lower end, said diptube being permeable only to said liquid propellant.

6. A valve and diptube means as in claim 4 wherein a part of said diptube wall is impermeable to said vapor, liquid propellant and liquid product, and a part of said wall is permeable only to said liquid propellant.

7. A valve and diptube assembly as in claim 1 comprising in addition an orifice to admit vapor to said valve means.

8. A valve and diptube assembly substantially as hereinbefore described with reference to any one of Figures 3-7 of the accompanying drawings.