1.0 Field of the Invention
This invention relates to a container for packaging liquid products, and more specifically to such a container that includes a closure which opens and closes automatically in the event of changes in pressure in the container. 
2.0 Discussion of Related Art
Packaging containers in the field of the invention, for example in bottle form, are known.  These packaging containers are provided, for example, with a membrane closure which opens when the pressure in the container increases and which automatically closes again when the pressure in the container falls.  To produce the increase in pressure, the side walls of the container have to be subjected to pressure so that the packaging container has to be made sufficiently flexible.  Unfortunately, the effect of this is that the container is relatively difficult to handle, particularly if it is partly empty.  In addition, a container of the type in question is difficult to keep upright or fix to a wall, for example where it is used in toilets as a liquid soap dispenser. 
3.0 Summary of the Invention
An object of the present invention is to provide an improved container for liquid products that is easy to handle at all liquid levels, and can be easily mounted on a wall or flat surface. 
In one embodiment of the invention, the container has at least one flat side wall for attaching it to a flat surface, and at least one concave or convex actuation surface formed in its side walls to enable pressure to be applied by the hand of the user. 
A packaging container designed in this way is easy to handle and easy to attach to a wall or the like.  Thus, it may be bonded to a flat wall, for example through its flat surface, or may be placed in a stand or in a wall-mounted holder, the at least one flat surface ensuring that the container is unable to rotate in the holder or stand.  The container is arranged with its closure underneath so that, whatever the filling level, liquid product is always present in the vicinity of the closure so that, by applying pressure to the actuation surface, the pressure in the container increases and the product can be dispensed.  The controlled actuation by application of pressure to the actuation surface prevents the container from becoming unstable. 
To facilitate handling, at least two actuation surfaces located on two opposite side walls are preferably provided. 
In one particularly preferred embodiment, the walls of the container are thinner in the region of the actuation surfaces than elsewhere.  The wall thickness of the container may thus advantageously be selected so that the container is basically stable and its side wall can only be indented or pushed inward in the vicinity of the actuation surfaces by normal application of pressure. 
To increase its stability and to enable it to be easily fixed in a wall-mounted holder or a stand, the container is provided with encircling profiles for insertion into a wall-mounted holder or a stand. 
In another preferred embodiment, the container has a rectangular cross-section with a rounded front wall.  The combination of this rounded front wall with flat side walls creates a decorative surface which can be seen from all three visible sides.  In addition, the fact that the flat rear wall is fixed to a wall surface by adhesive bonding thereto or anchoring in a wall-mounted holder protects the container from bulging when pressure is applied to the actuation surfaces.  Another advantage of this cross-sectional form lies in the combination of the advantages of rectangular and circular shapes, i.e. on the one hand there is the isomodular (rectangular) form while, on the other hand, an optimally squeezable bottle (rounded part) is available.