Patent Publication Number: US-2017349360-A1

Title: A cap for a container for a post-foaming gel cleansing composition

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to caps for containers for post-foaming gel cleansing compositions. 
     BACKGROUND TO THE INVENTION 
     Post-foaming gel cleansing compositions, such as that disclosed in EP1493802 are popular products. Currently they are dispensed from tinplate or aluminium cans via a “bag on valve” system, in which post foaming gel compositions are provided in a bag connected to the valve of a can and the can is pressurised (outside the bag) so as to compress the bag when the valve is opened, forcing the product out of the can. The pressure in the bag is provided by liquid butane and is in the region of 3 bar (300 kPa), which is sufficient to propel the foam, but ensures that it does not foam immediately on exit, but rather appears as a gel before foaming and does not jet too far out of the can—this can be a problem for gel-type products which do not atomise on exit from the can if pressure is high. 
     It is considered desirable to use plastic cans in place of the tinplate/aluminium cans currently used for reasons such as cost and the environment. However, plastic containers cannot simply substitute for the existing metal can for various reasons. For example, the same propellant, butane, should not be used as the propellant in a plastic container. The propellant used should be non-flammable and therefore gases such as compressed nitrogen or air should be used instead. This leads to a higher initial pressure in the vessel, with a typical initial pressure of 7-8 bar, reducing as product is expelled from the bag. 
     The caps of current cans for post-foaming gels are provided with a conduit defining a flow path from the valve to an exit orifice. The cap is provided with a nozzle extending inward from the side of the cap to locate just above a valve stem, a small hole is provided in the underside of the nozzle on the cap which connects the nozzle on the cap with an opening through the valve stem. An annular surface is provided around the small hole connecting the nozzles, which presses the upper annular surface of the valve stem, pushing it towards the body of the can to open the valve and actuate dispensing of the gel. 
     Use of an existing cap with current post-foaming gel cleansing compositions in plastic containers under higher pressure leads to an unacceptable jetting distance, because under the higher pressure gel is expelled from the bag at a higher rate through the conduit, which makes it difficult for a user to capture and control the expelled gel. If the diameter of the conduit through the nozzle in the cap is increased, the rate of flow out of the container can be reduced, reducing the jetting distance to an acceptable level (e.g. less than 60 cm). However, the quality of the gel expelled through the nozzle is notably poorer, and lacking in clarity. As has been set out e.g. in EP1493802, it is highly desirable that a post-foaming gel should be initially clear, not opaque or cloudy, so that the contrast between the gel and the lather can be fully appreciated. 
     It is an object of embodiments of this invention to ameliorate or alleviate these problems associated with packaging a post-foaming gel cleansing composition in a plastic container. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention there is provided a container comprising a body of plastics material containing a bag, the bag depending from a valve and containing a post-foaming gel cleansing composition, the valve having a valve stem, and a propellant being provided in the container outside the bag, so as to exert a pressure on the post-foaming gel cleansing composition in the bag, such that when the valve stem is depressed to open the valve the post-foaming gel cleansing composition is expelled therethrough; the container comprising a cap and the cap being provided with a conduit therethrough to guide the composition from the valve stem to an exit orifice, wherein the conduit comprises an expansion chamber for receiving the composition from the valve stem, a neck having a smaller diameter than the expansion chamber for receiving the composition from the expansion chamber, and a nozzle provided with an exit orifice and having a diameter larger than the neck. 
     According to another aspect of the invention there is provided a cap for a container comprising a body containing a bag, the bag depending from a valve and containing a post-foaming gel, and a propellant being provided in the container outside the bag, so as to exert a pressure on the post-foaming gel in the bag, such that when the valve is opened, the post-foaming gel is expelled therethrough; the cap being provided with a conduit therethrough to guide the composition from the valve to an exit orifice, wherein the conduit comprises an expansion chamber for receiving the composition from the valve, a neck having a smaller diameter than the expansion chamber for receiving the composition from the expansion chamber, and a nozzle provided with an exit orifice and having a diameter larger than the neck; characterised by a tapering mouth portion provided between the expansion chamber and the neck. 
     The provision of an expansion chamber into which the gel can initially expand, before being choked by the neck, then allowed to pass through the nozzle of the cap can allow for a sufficiently large diameter nozzle to avoid excessive jetting distance, whilst maintaining a high quality clear gel. The optional/preferred features below apply equally to both aspects. 
     Preferably the conduit comprises a frustoconical mouth portion between the expansion chamber and the neck. 
     Preferably the diameter of the exit orifice is between 2.5 and 3.5 mm, more preferably between 2.7 and 3.3 mm and preferably the nozzle is a substantially constant inner diameter of between 2.5 and 3.5 mm, more preferably between 2.7 and 3.3 mm. 
     Even more preferably the diameter of the exit orifice and the inner diameter of the nozzle is about 3 mm. 
     When the expansion chamber and neck of the invention are also provided, this size of nozzle/exit orifice results in an acceptable jetting distance, even for a product under higher pressure. 
     Preferably the expansion chamber and/or the neck and/or the nozzle are cylindrical. 
     Preferably the inner diameter of the neck is between 0.7 and 1.1 mm, more preferably between 0.8 and 1 mm and most preferably about 0.9 mm. 
     Preferably the inner diameter of the expansion chamber is between 2.5 and 3.5 mm, more preferably between 2.7 and 3.3 mm and most preferably about 3 mm. 
     Preferably the inner diameter of the expansion chamber is substantially equal to the inner diameter of the nozzle and/or the exit orifice. 
     Preferably the ratio of the inner diameter the nozzle and/or the expansion chamber to the diameter of the neck is from 2.5:0.9 to 3.5:0.9. More preferably from 2.7:0.9 to 3.3:0.9 and most preferably about 3:0.9. 
     Preferably the length of the neck is between 0.7 and 1.1 mm, more preferably between 0.8 and 1 mm and most preferably about 0.9 mm. 
     Preferably the ratio of the length of the neck to the diameter of the neck is from 0.6:1 to 1.5:1; more preferably the ratio is from 0.8:1 to 1:1.2 and most preferably most preferably about 1:1. 
     Preferably the length of the frustoconical mouth portion is between 0.3 and 0.4 mm; more preferably between 0.32 and 0.38 mm, and most preferably about 0.35 mm. 
     Preferably the length of the expansion chamber is from 1 mm to 2 mm, more preferably between 1.35 and 1.65 mm, most preferably about 1.52 mm. 
     Preferably the ratio of the length of the expansion chamber to the diameter of the expansion chamber is from 0.75:3 to 2.5:3, more preferably from 1:3 to 2:3; and most preferably about 1.5:3, e.g. 1.52:3. 
     The propellant may be a non-flammable compressed gas, preferably nitrogen or air. 
     With the gel in the bag, preferably the propellant is at a pressure of at least 2.2 bar to at least 7.3 bar until substantially all of the contents of the bag are dispensed. More preferably the initial pressure of the propellant (with the gel in the bag) is between 6 and 10 bar, more preferably between 7 and 8 bar. 
     Preferably the expansion chamber and the neck are coaxial. 
     Preferably the post-foaming gel is a post-foaming gel cleansing composition. 
     Preferably the post-foaming gel comprises a post-foaming agent. 
     Preferably the post-foaming agent is provided at a weight/weight ratio with respect to a base gel of 5:95 to 85:15 
     Preferably the weight/weight ratio of the post-foaming agent to the base gel is about 10:90. 
     Preferably the post-foaming agent is a non-polar saturated aliphatic hydrocarbon having from 3 to 6 carbon atoms. 
     Preferably the post-foaming agent is selected from butane, isobutane, isopentane, n-pentane, n-hexane, 2-methylpentane, 3-methylpentane 2,3-dimethylbutane and 2,2-dimethylbutane, and mixtures thereof. 
     Preferably the discharge is limited to between 0.75 to 1 m from the exit orifice. The discharge distance may be measured by standing a filled and pressurised unused container  1  on a flat (horizontal) surface and firmly pressing the operating button  5  fully. A measurement is made from the front of the container  1  to the furthest point at which gel contacted the flat surface. 
     The expansion chamber may be an accumulator, arranged to receive and accumulate gel and thereby ensure that there is a constant supply of gel to the neck to prevent the generation of foam. 
     The post-foaming gel composition may comprise water (greater than 50%), surfactants (selected from anionic, amphoteric and nonionic) greater than 5% and less than 30% and a post-foaming agent (5-15%) comprising at least one non-polar saturated aliphatic hydrocarbon having from 3 to 6 carbon atoms, and optionally containing emollients, humectants, preservatives, rheology modifiers, pH adjusters, dyes, fragrances, and/or chelating agents. 
    
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
       In order that the invention may be more clearly understood an embodiment thereof will now be described, by way of example only, with reference to the accompanying drawings, of which: 
         FIG. 1  shows a front view of a container according to the invention; 
         FIG. 2  shows a part-cutaway side view of the cap of the container of  FIG. 1 ; and 
         FIG. 3  shows a lateral cross section through part of the cap of the container of  FIGS. 1 and 2 . 
     
    
    
     With reference to the drawings, a container  1  comprises a plastic hollow generally cylindrical body  2  having a valve (not shown) from which a bag (not shown) depends (as described for example in U.S. Pat. No. 7,730,911 B2, the contents of which are incorporated by reference). The cylindrical body contains a propellant gas, e.g. compressed nitrogen at an initial pressure of 8 bar between the walls of the container and the bag, so as to expel a post-foaming gel cleansing composition (as described for example in EP1493802, the contents of which are incorporated by reference) from within the bag, via a tubular valve stem (not shown), in response to depression of the valve stem. 
     The container  1  comprises a cap  3  having an exit orifice  4  at the front, through which post-foaming gel cleansing composition is expelled in response to actuation of a button  5  formed on the cap  3 . 
     The cap  3  is generally frustoconical, and the top of the generally cylindrical container  1  also has a frustoconical top, extending upwards to the region where the valve (not shown) is attached. The base of the cap sits over the body of the container whilst a bead  6  is provided inward and upward of the base for connection to the valve and the generally cylindrical body. Once connected, the stem (not shown) of the valve (not shown) of the container extends upwardly from centre of the top of the body  2  to fit into an aligning cavity  7 , which, as best seen in  FIG. 3  comprises a cylindrical upper portion,  7   a , having an inner diameter approximately equal to the outer diameter of the stem of the valve arranged to snugly grip the outer surface of the stem, and a frustoconical lower portion  7   b  tapering away from the bottom of the cylindrical upper portion  7   a  and arranged to guide the stem into the upper portion  7   a  of the aligning cavity  7 . For example when a stem diameter is 3.9 mm, the cylindrical portion is 3.88 mm, so that a strong connection is made. The diameter of the smaller (upper) end of the frustoconical lower portion  7   b  is equal to that of the stem diameter, while an exemplary diameter for the wider end of the frustoconical portion of the aligning cavity  7  is 6 mm. 
     At the top of the cylindrical upper portion  7   a  of the aligning cavity, an annular, frustoconical, surface  7   c  is provided, extending inwardly and slightly upwardly from the upper circumference of the cylindrical upper portion, so as to sit atop the annular upper surface of the valve stem, so as to provide a depression surface to depress the valve stem and open the valve such that the post-foaming gel cleansing composition is expelled through the stem. The total length of the aligning cavity  7  may be 4.94 mm, with the frustoconical surface  7   c  at the top of the cavity being 0.44 mm high, and about a third of the remaining length being cylindrical  7   a  and the remaining two thirds being frustoconical  7   b.    
     From the inner, upper, edge of the annular surface  7   c  of the aligning cavity  7 , a cylindrical expansion chamber  8  extends upwardly. The expansion chamber  8  is 3.0 mm in diameter and 1.52 mm in length, thus having a volume of about 10.74 mm 2 . 
     The upper surface of the cylindrical expansion chamber  8  is once again annular, this time a flat annulus. 
     From the inner edge of the flat annulus which forms the upper surface of the expansion chamber  8 , a frustoconical mouth  9  having a pitch of 45 degrees and a height of 0.35 mm extends inwardly and upwardly. 
     The top edge of the frustoconical mouth is joined to a cylindrical cavity forming a neck  10 , which has a narrow diameter of 0.9 mm and a height of 0.9 mm. 
     This thin neck  10 , then opens to the bottom of a nozzle  11  which extends laterally away from the axially disposed aligning cavity  7 , expansion chamber  8 , frustoconical mouth  9  and neck  10 . The nozzle  11  is another substantially cylindrical cavity in the cap  3  and has a diameter of 3.0 mm. 
     A cap comprising these features may be, for example injection moulded from plastic, e.g. Polypropylene, with all of the features of the conduit (i.e. the nozzle  11 , the neck  10 , the mouth  9 , the expansion chamber  8  and the aligning cavity  7 ) provided on a movable portion  12  of the cap  3  that is connected to the rest of the cap, only at the front, below the exit orifice  4 , but is separated from the surrounding part  13 , so as to be pivotable when the button  5  is depressed, in order to allow the depression surface  7   c  of the aligning cavity  7  to be moved downwards against the annular upper surface of the stem (not shown) to initiate dispensing of the post-foaming gel cleansing composition. 
     The nozzle has a taper on either side of 0.5 degrees, and indeed slight tapers are included in other generally cylindrical portions, in order to allow the metal pin forming the nozzle in during moulding to be removed. 
     The container  1  may be manufactured by techniques well known to those in the art: attaching the valve (not shown), with the bag (not shown) attached, to the body  2  of the container, filling the bag with post-foaming gel composition and introducing compressed gas (e.g. nitrogen) between the bag and the walls of the body  2 . The cap  3  is then attached to the body  2  of the container by pressing it on, such that the aligning cavity  7  is aligned with the stem (not shown) of the valve (not shown) and the bead  6  clips into a groove (not shown) formed between the valve and the body  2  of the container  1 . 
     A suitable base gel for a post-foaming gel composition has the following ingredients: 
     
       
         
           
               
               
               
             
               
                   
               
               
                   
                   
                 Quantity 
               
               
                 Component 
                 Function 
                 (% w/w) 
               
               
                   
               
             
            
               
                 Water 
                 Solvent 
                 68.80-75.00 
               
               
                 Disodium EDTA 
                 Chelating Agent 
                 0.05-0.30 
               
               
                 Citric Acid 
                 pH Adjuster 
                 0.05-0.30 
               
               
                 Methyldibromo 
                 Preservative 
                 0.05-0.10 
               
               
                 Glutaronitrile 
               
               
                 and Phenoxyethanol 
               
               
                 Sodium Laureth Sulfate 
                 Primary Surfactant 
                 17.50-22.00 
               
               
                 Cocamidopropyl Betaine 
                 Foam Booster 
                  0.5-3.00 
               
               
                 PEG-7 Glyceryl Cocoate 
                 Skin conditioning agent/non- 
                 0.50-1.50 
               
               
                   
                 ionic gelling agent 
               
               
                 Glycerin 
                 Skin conditioning agent 
                 0.10-2.00 
               
               
                 Colour 
                 Colourant 
                 0.0005-0.0010 
               
               
                 Parfum 
                 Masking Agent 
                 0.70 
               
               
                 Laureth-4 
                 Gelling Agent 
                 0.00-8.25 
               
               
                   
               
            
           
         
       
     
     This base gel can be mixed at a ratio of 85:15 to 95:5 (e.g. 90:10) with a post-foaming agent, such as butane, isobutane, isopentane, n-pentane, n-hexane, isohexane (all 3 isomers: 2-methylpentane, 3-methylpentane and 2,3-dimethylbutane) and neohexane (2,2-dimethylbutane), and mixtures thereof to provide a post-foaming gel-cleansing composition. Other suitable gels are described for example in WO2011042759. 
     In use, a user holds the body  2  of the container  1  in one hand and depresses the button  5  with his/her finger or thumb, pressing it in the direction of the base of the container, i.e. “downwards”. Of course, the expressions “up” and “down” etc. have been used merely for ease of understanding and in use, the top of the container  1  need not be vertically disposed above the base, and it is most likely that the container will be held at an angle, at least somewhat upright, but possibly oriented more horizontally than vertically. The user&#39;s other hand is typically cupped beneath the exit orifice  4  to receive the post-foaming gel cleansing composition. Depressing the button  5  causes the movable portion of the cap  12  to move downwards towards the base, thus, the depression surface  7   c  of the aligning cavity  7  forces the stem downwards opening the valve. This causes the composition to exit the bag through the stem into the expansion chamber  8 . The gel is then forced from the expansion chamber through the mouth  9  into the neck  10  which restricts the flow owing to its narrow diameter. The composition then flows out of the narrow neck  10  into the broader nozzle  11  and hence its flow rate is reduced, such that having flowed along the nozzle  11  it exits the exit orifice  4  at a speed that avoids an excessive jetting distance. The flow through the expansion chamber prior to the neck and the nozzle maintains the clarity of the gel. 
     The discharge distance of a full can should be no more than 75 cm to 1 m. This is measured by standing a filled and pressurised unused container  1  on a flat (horizontal) surface and firmly pressing the operating button  5  fully. A measurement is made from the front of the container  1  to the furthest point at which gel contacted the flat surface. The above embodiment is described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims. In particular, whilst the description of the cap has been in relation to a plastic container for post-foaming gel cleansing compositions of the bag-on-valve type (and that is the intended product with which the cap is to be used), it is possible that the cap could find utility with other containers, for example for post-foaming gels other than cleansing compositions (e.g. shaving gels), with valves that do not have valve stems, or in metal cans with “bag-in-can” dispensing systems.