Tube for the distribution of a paste with stripes comprising a one-piece head with a double skirt

The invention concerns a tube for the distribution of a paste with stripes in which the head 1 which is connected by moulding to the skirt 4 of the tube has an inner skirt 8 which is in one piece with said head 1, which skirt 8 having flow openings 13, 14 for the stripe product, which skirt 8 has pairs of inner longitudinal ribs 17, 18, 22 for guiding the stripe product, disposed on respective sides of said openings 13, 14 and extending towards the top of the neck portion 7. The head of the tube is of a double skirt configuration, its outer skirt 16 forming the outside of the neck portion 7 and its inner skirt 8 extending from the top 5 of the head 1 and forming the inside of the neck portion 7 and the discharge duct 8 for the pasty product. Flow openings 13, 14, 15 are disposed in part at least above the notional extension of the slightly inclined rear surface 10 of the shoulder 2. The inner skirt 8 carries inner longitudinal ribs 26, 35 for retarding the flow of the main pasty product, and the ribs comprise ribs 26 extending from each flow opening 14 to at least the lower third of the portion of the skirt 8 which is disposed below the opening 14.

BACKGROUND OF THE INVENTION 
1. Field of the Invention; 
The invention concerns a flexible tube comprising a skirt and a head which 
are both at least in part of plastics material for the distribution of a 
paste with stripes. 
2. Description of Related Art 
FR-B-2 572 366 (=EP-A-0 182 725) to the present applicants describes such a 
tube in which the head comprises a neck portion which carries a discharges 
orifice and possibly a cap, and below the neck portion a shoulder by way 
of which the head is connected by moulding to the skirt of the tube, the 
head further comprising an inner skirt of plastics material which is in 
one piece with the head, being moulded in the same injection moulding 
operation as the head. The inner skirt has slots for the striped product 
to pass therethrough, and often pairs of longitudinal ribs which extend 
from the top of the slots towards the top of the internal surface of the 
neck portion, for guiding the coloured product for discharge thereof in 
the form of a stripe in the pasty material. The slots for the coloured 
product to pass therethrough go down to the lower end of the inner skirt 
when the product for the stripes is fairly viscous. 
With the tubes in accordance with the foregoing description, having 
longitudinal ribs bordering only over a distance of 2 mm the top of the 
longitudinal slots which extend to the bottom of the inner skirt and 
extending to a position in line with the orifice of the neck portion, 
experience has shown that the stripes produced in the distributed pasty 
material have woolly contours, particularly at the end of distribution of 
the pasty material. In addition, when beginning the step of pressing the 
tube, the coloured stripes appear clearly in the strand of paste which is 
discharged, only with a delay that is typically 10 to 20 mm after the 
strand of pasty material begins. 
In addition, and this is a nuisance, experience has shown that with the 
same tubes and also with tubes having a stripe-producing end portion 
fitted thereto, the inner, generally non-deformable skirt was often felt 
by the user as an obstacle to completing expulsion of the pasty material. 
The applicants sought to develop a tube for the distribution of a paste 
with stripes, having an inner skirt in one piece with the head of the 
tube, which with a structure which is favourable to mass-production 
moulding, both gives an improved quality of stripe and provides that the 
stripes appear closer to the beginning of the strand of pasty material. As 
an additional consideration, the applicants also tried to make the inner 
skirt deformable, so as to be compatible with the foregoing requirements 
and also eliminating the impediment flet by users at the end of the 
operation of pressing material out of the tubes. 
SUMMARY OF THE INVENTION 
Like above mentioned FR-B-2 572 366, the invention concerns a tube for the 
distribution of a paste with stripes comprising a skirt and a head which 
are both at least in part of plastics material, the head comprising a neck 
portion, said neck portion carrying a discharge orifice and, below the 
neck portion, a shoulder comprising a slightly inclined rear surface by 
way of which the head is connected by moulding to the skirt of the tube, 
said head further comprising an inner skirt of plastics material which is 
in one piece with the head and carries openings for the stripe product or 
products to pass therethrough, said skirt and the interior of the neck 
portion together forming the duct for discharge of the pasty product and 
bearing pairs of inner longitudinal ribs for guiding said striped product 
or products extending/at least from the top of the neck portion, siad head 
whose discharge orifice is possibly surmounted by a tear-off cap forming 
an assembly which is moulded in a single operation on the skirt of the 
tube. 
In accordance with the invention, the following three conditions are 
fulfilled at the same time: 
(a) the neck portion of the tube is of a double skirt configuration, its 
outer skirt and its inner skirt starting from the top thereof and forming 
the interior of the neck portion and therefore the whole of the duct for 
discharge of the pasty product, its two skirts defining therebetween an 
annular gap into which the stripe product or products passes; 
(b) said openings for the stripe product or products to pass therethrough 
are disposed in part at least and preferable entirely above the notional 
extension of the slightly inclined rear surface of the shoulder; and 
(c) the inner skirt bears inner longitudinal ribs which brake the main 
pasty product, comprising ribs going from each flow opening to at least 
the lower third of the portion of said skirt which is disposed beneath 
said opening. 
In the following description and in accordance with convention, the 
vertical direction is that of the axis of the tube and the term 
"longitudinal" denotes a direction which is close to the axial direction, 
the top of the tube corresponding to the neck portion thereof. The 
"horizontal" plane is any plane perpendicular to the above-mentioned axis 
and the words "inclined" or "slightly inclined" relate to inclination with 
respect to such a horizontal plane. 
By virtue of the first feature (a), there is an annular gap between the top 
of the inner skirt and the outer skirt or outer wall of the neck portion, 
and the coloured product passes into that annular gap so that, in 
accordance with the second features (b), the openings for the coloured 
product or products to flow therethrough can be taken up into that gap, 
above the extension of the rear surface of the shoulder, which is slightly 
inclined (typically at 20.degree. to 35.degree.). 
In addition, and in such a fashion as to be compatible with a moulding 
operation, to provide for good definition of the stripes, it was found to 
be necessary, in accordance with feature (c) to provide the inner skirt 
with inner longitudinal ribs preceding each opening, the function of such 
ribs being to brake the main flow of pasty material by locally grooving 
it, so that the impact thereof on the flows of stripe product or products 
issuing from the flow openings is reduced. 
In overall terms, by virtue of the combination of the three features 
referred to above, the first of those features resulting in a slower 
movement of the pasty product in the discharge duct by virtue of a 
reduction in the cross section thereof, upon comparative use of the tubes 
according to the invention and tubes in accordance with FR-B-2 572 366 of 
the same size (25 ml and with a skirt diameter of 22 mm) and filled with 
the same products, the following points were found: 
a substantial reduction in the length of strand of pasty product without a 
stripe, with the tubes of the invention (for example 5 to 6 mm instead of 
15 to 20 mm), and 
good definition of the coloured stripes with the same tubes. 
It can be noted that, by virtue of the invention of the inner skirt, the 
annular space between the inner skirt on the one hand and the shoulder and 
the skirt of the tube on the other hand is wider than in the situation 
where the inner skirt extends the neck portion of the tube (FR 2 572 366). 
That facilitates filling the coloured product and that product, depending 
on its viscosity, penetrates to a greater or lesser degree into the 
annular gap referred to above, which prolongs the annular space. 
That therefore provides a small reserve of coloured product at the location 
of and above the flow openings therefor, which is favourable to regularity 
of the flow of coloured product through those openings and also, as has 
been found, constancy of taste of the pasty material issuing from the 
tube. 
In order to facilitate progression of the coloured product towards the flow 
openings therefor, it is highly desirable for the rear surface of the 
shoulder, between its slightly inclined surface and the inner surface of 
the outer skirt which forms the outside of the neck portion, to comprise 
an inclined surface forming a bevel, preferably at 50.degree. to 
70.degree. with respect to the horizontal plane, and being substantially 
frustoconical. Such a bevel increases the entry diameter of the annular 
gap, that increase giving rise to an increase in the size of the annular 
cross section for the flow of coloured product towards the flow opening or 
openings therefor, which typically attains 80 to 120%. In addition, when 
the tube is pressed, the inclined bevel creates a flow of coloured product 
along its surface, directing the coloured product upwardly, which makes it 
possible to feed the product to flow openings which are disposed a little 
higher than when there is no bevel. The top of such openings is then 
preferably to be disponsed at the intersection of the notional extension 
of the bevel-forming inclined surface and the inner skirt or below that 
intersection. The provision of the circular bevel facilitates removal of 
the moulded component from the mould. 
Preferably, in order to permit the tube to be pressed without difficulty 
and to provide for optimum emptying of the tube, the inner skirt 
comprises, from each flow opening to the lower end thereof, a longitudinal 
zone of reduced thickness, which permits it to be flattened. The braking 
ribs then typically comprise pairs of ribs which are disposed on 
respective sides of the flow openings and then the corresponding 
reduced-thickness longitudinal zones. The reduced-thickness longitudinal 
zones are preferably reduced in thickness or grooved on the outside face 
of the inner skirt, which is advantages in regard to removal of the 
moulded component from the mould while facilitating access of the 
stripe-forming product or products to each of the corresponding flow 
openings. 
The tool assembly for injection moulding of the interior of the tube 
according to the invention typically comprises a central tool defining the 
interior of the inner skirt and a peripheral annular tool defining the 
exterior of the inner skirt, the two tools defining by virtue of mutual 
contact the flow openings and comprising between them and below each of 
the contact zones a longitudinal aperture, the thickness of which is 
markedly smaller than that of the sectorial apertures corresponding to 
moulding of the other zones or body portion of the inner skirt. So as to 
facilitate removal of the moulded component from the mould, the 
above-mentioned longitudinal aperture is of a thickness which increases 
downwardly while the sectorial apertures corresponding to moulding of the 
body portion of the inner skirt are of a thickness which varies in the 
opposite direction. 
The inner skirt of the tube according to the invention is thus 
distinguished in that preferably the thickness of each longitudinal 
reduced-thickness zone increases from the corresponding flow opening to 
the lower end of the inner skirt while the thickness of the body portion 
of the inner skirt decreases from said opening to said end. Typically, in 
axial section, the angle between the two faces of the body portion of the 
inner skirt and the angle between the two faces of the longitudinal 
reduced-thickness zones are then both between 0.degree.15' and 1.degree. 
Typically also the thickness of each longitudinal reduced-thickness zone of 
the inner skirt is between 0.15 and 0.35 mm in its upper half close to the 
corresponding opening and between 0.25 and 0.45 mm in its lower half. 
Particularly in their top part, each of the longitudinal zones forming the 
bottom of a groove bordered by the corresponding braking ribs, at any 
level perpendicular to the axis of the tube, is of a thickness which is 
much smaller than the thickness of the body portion of the inner skirt at 
the same level. In practice and preferably in regard to economy of 
material and volume, at a given level on the inner skirt, the thickness of 
said doby portion is between 2 and 4 times the thickness of the 
reduced-thickness zones as in the case of the upper half of said zones, 
and between 1.2 and 3 times the thickness of the reduced-tickness zones in 
the case of their lower half. Those arrangements which are compatible with 
industrial mass-production moulding are favourable both to flattening of 
the inner skirt at the end of the period of use of the tuve, and to 
providing stripes of high quality. 
It was surprisingly also found that, whereas such longitudinal 
reduced-thickness zones which are not bordered by ribs gave coloured 
stripes of variable quality in the course of use of the arrangement, it 
was sufficient to provide braking ribs of a reduced height of 0.2 to 0.3 
mm in order to produce stripes of high quality in the case of a main pasty 
product which is rather viscous. The reduced height of such braking ribs 
or lower ribs facilitates removal of the moulded component from the mould. 
In cases where the longitudinal braking ribs are distributed in pairs on 
respective sides of each flow opening and each subjacent longitudinal 
zone, which may or may not be of reduced thickness, the braking ribs are 
thus typically of a smaller height than the height of the guide ribs and 
between 0.2 and 0.7 mm, the height of the guide ribs itself being between 
0.4 and 1 mm. 
On that subject, it may be noted that the upper ribs or guide ribs for the 
stripe-forming product or products also perform a function of braking the 
main pasty product and that the minimal heights of each of those two types 
of ribs, both the upper ribs and the lower ribs, in order to produce 
stripes of high quality, must be increased when the main pasty product is 
less viscous. The braking ribs may also comprise longitudinal bosses to 
provide for additional braking of the main pasty product, being disposed 
between the pairs of braking ribs on respective sides of the flow openings 
or between the guide ribs. Preferably each guide rib is extended to the 
discharge orifice of the tube, the free edge of said rib then being in 
alignment with the inner surface of the orifice. 
In a particularly simple and advantageous fashion in regard to production 
of the moulding tools and removal of the moulded component from the mould, 
the braking ribs and the guide rib bordering each flow opening on the same 
side form a continuous longitudinal rib of a height which increases in an 
upward directions. 
It was found that, with a given size of discharge orifice, it is preferable 
for the top of the inner skirt, being the skirt forming the discharge duct 
for the pasty produt, to be connected to the inside surface of the 
discharge orifice by way of a convergent surface, the cross section of the 
orifice being typically 0.6 to 0.85 times the area of the lower opening of 
the inner skirt. The height of the discharge orifice being slight, 
typicaly from 1.5 to 3 mm, the constriction in respect thereof does not 
cause a substantial braking effect and a wider discharge duct than that 
orifice is then preferable, as has been noted, to a narrower discharge 
duct with a connecting surface leading to the divergent orifice. In 
addition, to facilitate removal of the moulded component from the mould, 
the inner skirt is of an inside diameter which progressively decreases 
slightly in an upward direction. 
As has already been pointed out, the flavour of the pasty product is fairly 
well preserved by virtue of the provision of a reserve of product for 
forming the stripes in the annular gap. However the flavour may be better 
preserved by providing the rear of the shoulder of the tube with an 
annular ring of metalloplastic material or of a plastics complex material, 
being fixed by moulding and comprising at least outer layers of 
polyethylene or possibly polypropylene and an intermediate layer of 
aluminium or barrier plastics material. 
Moreover, to distribute a paste with strips of different colours or 
natures, the tube of the invention comprises partitioning means which 
separate the gap between its inner skirt and its shoulder into sectors 
which each contain a flow opening. The number of such partitioning means 
and flow openings are typically the same, from 2 to 6. 
The examples and the drawings will permit the description of the tube of 
the invention to be completed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS. 
The head 1 of the tube in FIG. 1 comprises a shoulder 2 of which the lower 
end is connected by moulding at the junction 3 to the skirt 4 of the tube 
of an outside diameter of 22 mm. The head 1 comprises a top portion 5 
which at its centre has the discharge opening 6 which is of an inside 
diameter of 7.5 mm and, connected to the top portion 5, an outer skirt 16 
forming the screwthreaded outside of the neck portion 7 and connected to 
the shoulder 2 and an inner skirt 8 which is 18 mm in height, forming the 
interior of the neck portion 7 and on its own forming the whole of the 
duct 8 for discharge of the pasty product. The inside surface of the outer 
skirt 16 is 12 mm in diameter and the top of the inner skirt 8, which is 
of an outside diameter of 10 mm, is separated from the outer skirt 16 by 
the annular gap 9 which is 0.9 to 1 mm in width. The rear surface of the 
shoulder 2, between its surface 10 which is inclined at 30.degree. and the 
inside surface 11 of the outer skirt 16, comprises a frustoconical chamfer 
12 which is inclined at an angle of 60.degree., doubling the annular area 
for flow of the coloured product towards the flow openings leading into 
the discharge duct as indicated at 13 and 14. 
The inner skirt 8 has five flow openins which are regularly distributed 
arount its circumference, three thereof being indicated at 13, 14 and 15 
in FIGS. 1 to 4, each one as indicated at 14 being of a substantially 
rectangular contour measuring 0.8.times.1.1 mm in its longitudinal 
direction and being bordered on respective sides by two longitudinal ribs 
17 and 18 which extend from a level disposed at 1 mm from the lower end 19 
of the outer skirt 8 to the lower end 20 of the discharge orifice 6. The 
ribs 17 and 18 are of a height which regularly increases in an upward 
direction, said height thus varying from 0.3 to 0.5 mm in their portion 26 
for producing a braking effect alone, below the openings as at 14, and 0.5 
to 0.6 mm in their guide and braking portion extending from the openings 
such as indicated at 14, to the orifice 6. The upper or free edge 21 of 
each rib as indicated at 22 is disposed in alignment with the inside 
surface 23 of the discharge orifice 6 so as not to leave any unevenness 
impeding the pasty product in its flow through the arrangement. Each flow 
opening as indicated at 13 to 14 is entirely contained between the 
notional extensions of the slightly inclined surface 10 and the 
frustoconical chamfer or bevel 12 of the rear surface of the shoulder, the 
bottom of said openings being about 0.5 mm above the surface 10 and the 
inner skirt 8. 
Beginning at the bottom as indicated at 24 of each opening as indicated at 
14 is a longitudinal reduced-thickness zone 25 which is of the same width 
0.6 mm as the opening on the outer side, as indicated at 14, extending 
downwardly to the bottom of the inner skirt 8, its thickness then 
regularly increasing from 0.2 mm below the opening 14 to 0.3 mm at the 
bottom of the skirt. The zone 25 is bordered over the major part of its 
length by lower braking portions as indicated at 26 of the longitudinal 
ribs 17 and 18. The thickness of the body portion 27 of the inner skirt 8 
regularly decreases in a downward direction from a thickness of 0.8 mm to 
0.6 mm. FIGS. 1 to 3 show views in axial section of the position of the 
longitudinal ribs and the grooves 28 and 32 that they define. The groove 
28 at the top, or the guide groove (FIGS. 1 and 2), between its portions 
of ribs serving to guide the coloured product as indicated at 30, has a 
reduced-thickness bottom 31 which is 0.8 mm in thickness while the bottom 
groove 32 which extends the top groove 28 and which serves for braking the 
flow of main pasty product before it reaches the level of the openings 
such as indicated at 13 and 15, between its portions of braking ribs as 
indicated at 26, has a bottom formed by a longitudinal reduced-thickness 
zone 25 which varies in thickness from 0.2 to 0.3 mm (FIG. 3). The 
reduction in thickness of the lower edge 33 of each opening as indicated 
at 13 (FIGS. 1 and 4) makes it easier for the stripe-forming product to 
pass therethrough. 
The lower skirt 8 is slightly frustoconial or convergent, its inside 
diameter varying from 9 mm at its lower open end to 8.4 mm in its upper 
part. The upper part is connected by a convergent connecting surface 34 to 
the inside surface 23 of the discharge orifice 6, being of an inside 
diameter of 7.5 mm and 2 mm in height. Those arrangements make it easier 
to remove the moulded component from the mould and the entry 
cross-sections of the inner skirt and the discharge orifice are 
respectively 63 mm.sup.2 and 44 mm.sup.2 in area, permitting an easier 
progression in the flow of the pasty product towards the discharge orifice 
6. 
In an alternative embodiment, for a less viscous coloured product, the 
inner skirt 8 was provided with 5 additional longitudinal braking bosses 
as indicated at 35 (see FIG. 2), forming flat portions of a width of 2 mm 
and of an increased thickness of 0.5 mm, each being disposed between the 
pairs of ribs as at 17 and 18 on respective sides of two adjacent openings 
13 and 14. The bosses 35 extend in this case over the entire height of the 
longitudinal ribs such as 17. 
FIG. 1 also shows the position of an annular metalloplastic disc 36 
consisting of 5 layers forming a barrier in relation to flavourings, 
lining the rear 10 and 12 of the shoulder 2 and being connected to the 
shoulder 2 by the moulding operation, the surface layers 40 thereof being 
of polyethylene the intermediate layer 39 being of aluminum. The flexible 
disc 36 is fitted around the annular tool forming the annular chamber 37 
and the annular gap 9, which is particularly simple. 
TESTS 
1. 5 tubes in accordance with the foregoing description, the head 1 being 
of polyethylene and the skirt 4 being metalloplastic, not any bosses 35 or 
metalloplastic disc 36, were compared to 3 tubes in accordance with the 
prior art (FR 2 572 366) of the same capacity of 25 ml and the same 
diameters in respect of the discharge orifice (7.5 mm) and the skirt (22 
mm), with the same pasty products in the two types of tubes. Tests 
relating to distribution of the pasty product give coloured stripes of an 
outline which is not clearly marked, in the case of the prior-art tubes. 
In the case of the tubes according to the invention, the results obtained 
were as follows: 
stripes began markedly earlier, at 5 to 6 mm from the beginning of the 
strand of pasty product discharged from the tube, instead of 15 to 20 mm 
as with the prior-art tubes; 
clearly defined strips with clearly marked edges; and 
no difficulties in pressing out the tubes at the end of the period of use 
thereof. 
2. With a main pasty product and a coloured product less viscous than in 
the previous case, there was an improvement in the clear outlines of the 
coloured stripes with tubes according to the invention provided with 
longitudinal bosses as indicated at 35. 
3. Three tubes of the same geometry as in the first series of tests were 
prepared, the structure of each tube being supplemented by five radial 
partitions disposed between the flow openings for the pasty product, with 
the lower horizontal edge disposed just below the shoulder, the position 
38 of that lower edge being shown in FIG. 1. Partitions 41 and 42 are 
shown in FIG. 4, dividing the annular gap on either side of flow opening 
13. 
Tests relating to the distribution of pasty product were then effected with 
five different coloured products which in respect of each tube were placed 
in each of the sectors defined by the foregoing radial partitions. The 
distribution tests gave stripes in the five colours, with an excellent 
degree of definition, on the strands of pasty product discharged from the 
tubes. 4. Tubes of a skirt diameter of 35 mm and of a capacity of 150 ml 
of product with the same head structure were produced, the shoulder 2 
simply being extended outwardly for connection thereof to the skirt. The 
gap and the annular chamber were filled with stripe-forming product to the 
same level, substantially to the bottom 38 of the shoulder 2 (see FIG. 1). 
It was found that it was easy to expel the pasty product, with stripes 
which appear early and which are clearly marked. It was also found that 
the stripes persisted to the end of distribution of the pasty product. 
The invention simultaneously provides the following: 
early appearance of the coloured stripes; 
stripes which are particularly well defined, with clearly marked outlines; 
an one-piece design configuration which is easy to mould and which is 
suited to mass production; and 
according to the last test, a head structure which can be adapted to 
various capacities, with regulating conditions which are not critical; 
possibly, by virtue of the reduced-thickness longitudinal zones, a tube 
head with an inner skirt which flattens out without causing difficulty or 
awkwardness at the end of use of the tube.