Flexible tube, resistant to stress cracking and impermeable to water vapour

#The invention relates to a package, in particular to a flexible tube, which is resistant to stress cracking and impermeable to water vapor.

#Pasty substances, such as tooth pastes, pharmaceutical products, cosmetology products, food products, hygiene products, dentifrices, cleaning products, fatty products, greases, mastics and glues, are often offered in packages of the tube type. These tubes are made up of a tubular body of constant cross section, of circular, oval or other shape. The tubular body, which forms what is called the “skirt” in the following, has a first end generally closed by heat fusing and a second opposite end configured so as to form a head for distribution of the products contained in the skirt. The distribution head is provided with a screwed, snapped or other closing device, of standard cap, service cap or other type.

#In order to extract the product from the tube, the consumer presses the wall of the skirt, which undergoes increasing pronounced deformation and folding as the tube is emptied.

#The invention will be better understood and other aims and advantages of it will appear more clearly upon reading of the following explanatory description given in reference to the appended figures in which:

#FIG. 1 diagrammatically represents the zones of selection of the fluidity indexes and densities of the ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers according to the particular properties which are desired for the tube which is obtained.

#FIG. 2 represents, in the form of a curve, the thicknesses of the wall of the skirt at mid-height of the skirt which are to be chosen as a function of the desired length of the skirt, when the wall of the tube is made of an ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers having [a fluidity index] between 5 and 10 g/10 min inclusive, and preferably between 5 and 9 g/10 min inclusive, in order to obtain a tube with improved flexibility.

#In a general manner, the tubes consist of a skirt, of constant cross section, of circular, oval or other shape, closed at one of its ends by heat fusing, after filling of the tube with the pasty product which is to be packaged. At the other end, the tube is configured in such a way as to form a distribution head for the product contained in the skirt.

#The capacity of the tube is its primary characteristic. In the particular case of a tube with constant circular cross section, the capacity is defined by the length and the diameter of the skirt, that is to say by the length and the diameter of the circular cross section of the skirt.

#The capacities ordinarily offered on the market are between 2 and 500 mL. The ratios of the skirt lengths with respect to the diameter of the skirts ordinarily observed on the market are between 2.5 and 6, and preferably 4.