Abstract:
Contoured bags are provided for use in pressurized dispensing containers, e.g., for personal care products such as shaving preparations.

Description:
TECHNICAL FIELD  
       [0001]     This invention relates to dispensing personal care products, e.g., shaving preparations, and more particularly to dispensing products from a pressurized can.  
       BACKGROUND  
       [0002]     In some cases, personal care compositions such as shaving preparations are dispensed from pressurized containers that include an outer canister, an inner bag containing the composition, and a propellant between the container and the bag. The propellant applies pressure to the outer wall of the bag, forcing the composition out of the bag through a valve at the container outlet when the user presses an actuator button on the container. If the composition includes two components that must be separated prior to dispensing, the container may include a second bag disposed within the inner bag, i.e., the container may be a “bag-in-bag” system in which the propellant acts simultaneously on both bags.  
         [0003]     While such containers generally work well, some of the composition may get trapped in the bottom of the bag(s), and thus to be wasted rather than being delivered to the consumer and requiring the manufacturer to fill the container with an extra volume of the composition just so that the advertised volume will be dispensed. Moreover, in a bag-in-bag system, more material may be trapped in the outer bag than the inner bag, and thus the ratio of the two components generally may not remain constant as the contents of the container are dispensed.  
       SUMMARY  
       [0004]     The present invention features bags for pressurized containers of the type described above. The bags have a shape that prevents material from being trapped in the bottom of the bag, which reduces residue and allows more product to be delivered to the consumer rather than wasted. In a bag-in-bag system, the shape prevents material from getting trapped on the bottom of the outer bag, which generally allows the ratio of the two components to remain substantially constant as the contents of the container are dispensed. The bags are also easy to assemble into the outer canister during manufacturing and easy to fill.  
         [0005]     In one aspect, the invention features a dispensing system including (a) a pressurized canister having top defining an opening, a bottom, and a generally cylindrical side wall, (b) a flexible bag, disposed within the canister, containing a component to be dispensed from the dispensing system, (c) a valve assembly, in fluid communication with the bag, sealing the opening of the canister and including a valve defining an outlet through which the component can exit the dispensing system, and (d) an actuator, configured to open the valve in response to actuation by a user. The bag includes an upper portion and a tapered lower portion, the lower portion having a sidewall that tapers away from the side wall of the canister as the bag approaches the bottom of the canister.  
         [0006]     In another aspect, the invention features a dispensing system including (a) a pressurized canister having top defining an opening, a bottom, and a generally cylindrical side wall, (b) an outer bag, disposed within the canister, containing a first component to be dispensed from the dispensing system, (c) an inner bag, disposed within the outer bag, containing a second component to be dispensed, (d) a valve assembly, in fluid communication with the inner and outer bags, sealing the opening of the canister and including a valve defining outlets through which the components can exit the dispensing system, and (e) an actuator, configured to open the valve in response to actuation by a user. The inner and outer bags each include an upper portion and a tapered lower portion, the lower portion having a sidewall that tapers away from the side wall of the canister as the bag approaches the bottom of the canister.  
         [0007]     In some implementations, the valve assembly comprises a single, unitary valve stem, e.g., a female valve stem.  
         [0008]     Generally, the products described herein are pressurized, i.e., the contents of the container are under pressure, for example pressure applied by a propellant or by a mechanical force such as a spring.  
         [0009]     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features and advantages of the invention will be apparent from the description and drawings, and from the claims.  
     
    
     DESCRIPTION OF DRAWINGS  
       [0010]      FIG. 1  is a side view of a bag according to one embodiment of the invention.  
         [0011]      FIG. 1A  is a detail view of area A of the bag shown in  FIG. 1 .  
         [0012]      FIG. 2  is a side view of the bag of  FIG. 1  disposed in a canister, with the front half of the canister cut away to show the bag.  
         [0013]      FIG. 3  is a cross-sectional view of a bag-in-bag two component dispensing system according to one embodiment of the invention.  FIG. 3A  is an enlarged detail view of area A in  FIG. 3 .  
         [0014]      FIG. 4  is a perspective view showing the inner bag of the dispensing system shown in  FIG. 3 . 
     
    
     DETAILED DESCRIPTION  
       [0015]     Referring to  FIGS. 1-1A , a bag  10  includes an upper, straight-walled portion  12  and a lower, contoured portion  14 . A transition area  16  separates the straight-walled portion and the contoured portion. The transition area  16  generally has a radius of curvature R 1  of about 20 mm to about 200 mm, preferably about 30 to 80 mm. Generally, the larger R 1 , the easier it is for the bag to collapse, facilitating both delivery of product to the user and assembly of the bag into the can. However, making R 1  larger also tends to reduce the volume of the bag, requiring a larger (typically longer) canister to contain the same volume of product. If desired, the transition area may be omitted, and the bag may contour smoothly from the top to bottom. However, this geometry may reduce the volume of the bag to an undesirable extent in some cases. Alternatively, the bag may include two or more transition areas, at which the contour angle of the bag changes, if desired.  
         [0016]     The contoured portion  14  terminates in a base portion  18 . The contoured portion tapers at an angle that is governed by the length of the bag that is permitted by the packaging requirements, the volume that the bag must contain, and the desired shape of the base portion  18 .  
         [0017]     Preferably, the base portion is smoothly rounded and relatively narrow, e.g., width W is within about ±5 mm of the diameter of the canister opening, to facilitate insertion of the bag into the canister while maximizing the volume of the bag. Width W is measured at the change in radius of curvature of the bag that is closest to the bottom of the bag. It is preferred that the base portion not come to a sharp point, to avoid trapping of material in the base portion and to maximize the volume of the bag. Generally, it is preferred that the radius of curvature R 2  of the base portion be from about 10 mm to about half of width W (W/2).  
         [0018]     Referring to  FIG. 1A , it is generally preferred that the shoulder  20  of the bag, adjacent the neck  22 , conform as closely as possible to the contour of the inner wall of the canister  24  ( FIG. 2 ) in this area. Preferably, at any point along the shoulder of the bag, the radius of curvature (R 10 , R 20 ) of the bag  10  is within about ±20%, more preferably within about ±10%, of the radius of curvature of the canister  24  at the same point. It is also generally preferred that the transition area  21  between the neck and shoulder be smoothly curved, as shown. In some embodiments, the neck  22 ′ may be threaded (e.g., as shown in  FIGS. 3, 3A , and  4 ), in order to provide a secure connection of the bag to a valve  26  ( FIG. 3 ) that controls dispensing of material from the canister.  
         [0019]     Bag  10  may be formed of any desired flexible sheet material. Typically, the bag is formed of a material that may be blow-molded, e.g., a polymer such as polyethylene or polypropylene, and has a wall thickness of about 0.1 to about 0.5 mm.  
         [0020]     Bag-in-bag systems, discussed above, utilize a bag-in-bag arrangement such as that shown in  FIG. 3 . The bag-in-bag system  180  includes an outer bag  200 , similar to bag  10  described above, and an inner bag  202  disposed within the outer bag. The top edge  201  of outer bag  200  is crimped to a rim  203  of the canister  24 . The inner bag  202  includes a neck  22 ′ that is mounted in threaded engagement to a valve The two bags contain first and second components of a composition to be dispensed, maintaining the components separate during storage.  
         [0021]     A lower portion  210  of the outer bag  200  is contoured to match the contour of the inner bag  202 . In particular, the lower portion  210  tapers inwardly in the same manner as the corresponding lower portion  212  of the inner bag, so that the walls of the two bags are generally parallel in this area. This configuration tends to prevent material from getting trapped in the bottom of the outer bag, which reduces residue and allows more product to be delivered to the consumer rather than wasted. Because less material is trapped in the bottom of the outer bag, the ratio of the two components generally remains constant as the contents of the container are dispensed. Preferably, in bag-in-bag systems, the contour of the lower portion of the inner bag follows the contour of the lower portion of the outer bag as closely as possible.  
         [0022]     As shown in  FIGS. 3 and 4 , the inner bag may include a tapered upper portion  214  as well as a tapered lower portion, so that the bag is generally diamond-shaped in cross-section. This shape allows the two bags to contain substantially the same volume of the two components. If it is desired that the two bags contain different relative amounts of the components, the shape of the upper portions of the two bags can be adjusted accordingly.  
         [0023]     Other embodiments are within the scope of the following claims.