Source: http://www.allindianpatents.com/patents/205958-a-tube-made-up-of-a-skirt-and-a-distribution-head
Timestamp: 2018-12-19 12:35:16
Document Index: 34235624

Matched Legal Cases: ['art 9', 'art 8', 'art 8', 'art 8', 'art 9', 'art 9', 'art 8']

Indian Patents. 205958:A TUBE MADE UP OF A SKIRT AND A DISTRIBUTION HEAD
A TUBE MADE UP OF A SKIRT AND A DISTRIBUTION HEAD
1. A tube made up of a skirt and a distribution head, characterized by the fact that: - its wall is made of an ethylene-linear C4 to 10 olefin copolymer or of a mixture of ethylene-linear C4 to 10 olefin copolymers having a fluidity index (MFI) measured according to the ISO 1133 standard between 3 and 10 g/10 min, and preferably between 3,5 and 9 g/10 min inclusive, and a density between 0.880 g/cm3 and 0.935 g/cm3 inclusive, and preferably between 0.900 and 0.930 g/cm3, by the fact that the skirt has a wall thickness at mid-height between 0.30 and 1.00 mm inclusive, and preferably between 0.35 and 0.95 mm inclusive, and a length between 40 and 200 mm inclusive, and by the fact that - the skirt and the distribution head are manufactured in a single operation of injection in an injection mold, which has cavity insert (5) and insert (4), said insert having central part (8) whose free upper end (9) and rests centered on cavity insert (5) during the phase of iniection of the tube, from which it results that the tube is flexible, resistant to stress cracking and impermeable to water vapor.
THE PATENTS RULES; 2003
"A TUBE MADE UP OF A SKIRT AND A DISTRIBUTION HEAD"
CEP INDUSTRIE, a French company of Zi du Tiennon, F-63550 St. Remy-sur-Durolle, France
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.
The skirt of the tube must therefore be produced out of a flexible material. This material must also be capable of heat fusing. It must also have characteristics of resistance to-stress cracking and impermeability to water vapor in order to meet the specifications of compatibility of the products which are intended to be packaged in the tube.
Currently, the tubes which meet all these criteria are most often manufactured by assembling or duplicate molding of the distribution head produced by injection and the skirt produced by extrusioin. Another process, little used and expensive, consists of forming the skirt by displacement of the mold cavity following injection of the head, process called injection blow molding.
EP 0 856 554-A describes an injected packaging with improved resistance to stress cracking, which has a wall consisting of a thermoplastic mixture containing a first ethylene-C4 to C5 olefin copolymer and a second ethylene-C6 to C10 olefin copolymer. It is specified in this document that the mixture of these two copolymers must have a high fluidity index (standard ISO 1133) on the order of 10 g/10 min in order to be suitable for injection molding of objects with a wall of small thickness, hence the use in the mixture of an ethylene-C4 to C5 olefin copolymer with an MFI between 10 arid 20 g/10 min, which is a material which is not resistant to stress cracking according to the specifications generally required. Furthermore, this document is silent as to the properties of flexibility of the tube as a function of the thickness of the wall and as to the properties of impermeability of the wall to water vapor.
these characteristics are incompatible with the injection process according to prior art when they are simultaneously required.
To this effect, the invention proposes a tube made up of a skirt and a distribution head, characterized by the fact that its wall is made of an ethylene-linear C4 to 10 olefin copolymer or of a mixture of ethylene-linear C4 to 10 olefin copolymers having a fluidity index (MFI) measured according to the ISO 1133 standard between 3 and 10 g/10 min inclusive, and preferably between 3.5 and 9 g/10 min inclusive, and a density between 0.880 and 0.935 g/cm3 inclusive, and preferably between 0.900 and 0.930 g/cm3 inclusive, by the fact that the skirt has a wall thickness at mid-height between 0.30 and 1.00 mm inclusive, and preferably between 0,35 and 0.95 mm inclusive, for a length between 40 and 200 mm inclusive, and by the fact that the head and the skirt are manufactured in a single operation of injection in a mold, in order to obtain a flexible tube which is resistant to stress cracking and impermeable to water vapor.
In a preferred embodiment of the invention, the mixture of ethylene-linear C4 to 10 olefin copolymers is either a mixture of ethylene-linear C4 t0 5 olefin copolymers or a mixture of ethylene-linear C6 to 10 olefin copolymers.'
In a preferred embodiment, said end 9 is in the shape of a reentrant cone, and the angles a between channels 10 and the vertical axis of cavity 5 are less than 90°.
With regard to the materials, one will choose a fluidity index of the ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers between 5 and 10 g/10 min inclusive, and preferably between 5 and 9 g/10 min inclusive, and a thickness of the wall at mid-height of the skirt situated on the curve represented in Figure 2, as a function of the length of the skirt + or -0.05 mm, in order to obtain a tube with improved flexibility.
One will select the fluidity index of the ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers to be between 3 and 6.5 g/10 min inclusive, and preferably between 3.5 and 6.5 g/10 min inclusive, and a thickness of the wall at mid-height of the skirt on the curve represented in Figure 3, as a function of the length of the skirt + or - 0.5 mm, in order to obtain a tube with improved resistance to stress cracking, particularly in the presence of surfactant products.
Preferable in this case is a wall made of a mixture of: a) 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to 10 olefin copolymer having a density between 0.900 and 0.920 g/cm3 inclusive, and [b] 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to 10 olefin copolymer having a density between 0.920 and 0.935 g/cm3 inclusive, in order to obtain a tube with reinforced impermeability to water vapor and with optimized flexibility as a function of the thickness of the wall at mid-height of the skirt.
Preferably, the waJJ is a mixture of; a) 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 6.5 g/10 min
inclusive and a density between 0.900 and 0.920 g/cm3 inclusive, and b) 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 6.5 g/10 min and a density between 0.920 and 0.935 g/cm3 inclusive, in order to obtain a tube with reinforced impermeability to water vapor and optimized flexibility as a function of the thickness of the wall at mid-height and of the length, of the skirt.
More preferably, the wall is a mixture of: a) 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 5 and 6 and a density equal to 0.919 g/cm3, and b) 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 4 g/10 min and a density equal to 0.935 g/cm .
Most preferably, each ethylene-octene copolymer represents 50 wt% of said mixture.
In yet another embodiment, the tube has a wall made of a mixture of: a) 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 5 g/10 min and a density equal to 0.915 g/cm3, and b) 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 4 g/10 min and a density equal to 0.935 g/cm3, in order to optimize the resistance to stress cracking and impermeability to water at the expense of less flexibility of the wall of the tube.
Figure 1 diagrammatically represents the zones of selection of the fluidity indexes and densities of the ethylene-linear C4 t0 10 olefin copolymer or mixture of these copolymers according to the particular properties which are desired for the tube which is obtained.
Figure 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.
Figure 3 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 3 and 6.5 g/10 min inclusive, and preferably between 3.5 and 6.5 g/10 min inclusive, in order to obtain a tube with improved resistance to stress cracking, in particular in the presence of surfactant products.
Figure 4 represents a mold of prior art which can be used for the injection of the tube according to the invention.
Figure 5 represents a mold of prior art which is preferably used for the injection of the tube of the invention.
Figure 6 diagrammatically represents the flow sheets during injection of the tube of the invention with the mold represented in Figure 5.
Figure 7 is an enlarged view of the part noted VII in Figure 5.
Figure 8 diagrammatically represents a perspective view of the head of the mold which is to be used most preferably for injection of the tube of the invention.
Figure 9 is a view in section according to axis IX-IX of Figure 8.
Figure 10 is a top view of upper part 9 of the mobile part of the mold represented in Figure 7.
Stress cracking or "stress cracking" is a phenomenon of physicochemical attack of a surfactant product on a polymer. This phenomenon is expressed by the formation of micro-cracks in the polymer, which can go as far as bursting the wall. The risk of bursting is particularly great in the vicinity of the heat fused end.
The tube is filled with a surfactant solution with a concentration of 0.3%, for example, of Igepal CO 630 or ethoxylated nonylphenol in distilled water, and is fused at the end by hot squeezing. The tube is placed in an oven at 55°C for 24 hours. Coming out of the oven, a pressure of 2 to 4.5 bars is applied for 2 to 10 seconds, according to the specifications of the orderer. Coming out of the oven, the tube must not have any leak at the fused part or any crack or tear of the wall.
Currently, in particular in cosmetology, the packaged products are evolving towards aqueous base emulsions. The packaging of these products must therefore meet increasingly severe criteria of impermeability to water vapor in order to prevent an excessive loss of weight by evaporation of the water through the flexible wall, and consequently a modification of the "pasty" character of the cream packaged in the tube. Furthermore, the measurement of the permeability to water is always done in percentage of the loss of weight of the cream by evaporation, with respect to the initial weight of cream contained in the tube. The weight loss ratio therefore depends simultaneously on the porosity with regard to water and on the ratio between the surface area of evaporation, that is to say the surface area of the skirt, and the volume of cream contained in the tube.
The test of impermeability to water consists of placing the tubes, which are filled beforehand with the product which to be tested and are fused, in an oven whose temperature, depending on the tests, is between 45 and 55°C, for a period of time, depending on the tests, between 2 and 8 weeks.
As an example, a loss of weight of 30% [sic; 3%] for a quantity of cream of 5 grams in a tube with diameter 19 [sic] represents an evaporation of 0.15 grams of water. This is therefore an extremely restrictive test in the case of an exposure of the tube in an oven at 45°C for 8 weeks.
For the same reason, the difficulty of the test increases when the tube is only partially fitted, which [condition] a)so contributes towards increasing the ratio of evaporation surface area with respect to the volume of cream.
Furthermore, the density of the copolymer has no significant influence on the injectability but has a determining influence on the flexibility of the wall. As an example, two ethylene-octene copolymers of the same grade (for example, 6) form a stiff wall for a density of .950 g/cm3 and a very flexible wall for a density of 0.900 g/cm3, if this wall has a thickness of 0.6 mm.
Contrary to the presumptions of prior art, it has been found that an ethylene-linear C4 to C10 olefin copolymer or a mixture of ethylene-linear C4 to C10 olefin copolymers having a fluidity index (MFI) measured according to the ISO 1133 standard between 3 and 10 g/10 min, and preferably between 3.5 and 9 g/10 min, and a density between 0.880 and 0.935 g/cm3, that is to say when the copolymer or mixture of these copolymers has a fluidity index and a density included in the white zone noted [a,b,c,d] in Figure 1, [it] can be injected without destruction by exceeding the limit shearing speed and/or exceeding the limit temperature, in order to form a tube whose skirt has a wall thickness between 0.30 and 1.0 mm, and preferably between 0.35 and 0.95 mm, with a skirt length between 40 and 200 mm.
In effect, and as illustrated in Figure 1, when the MFI of the ethylene-linear C4 to10 olefin copolymer or mixture of these copolymers is less than 3, the material is no longer injectable because of exceeding the limit shearing speed in the flow path (length/thickness ratio) of the skirt required in order to keep the flexibility of the tube. In the same way, when the MFI of the ethylene-linear C4 to10 olefin copolymer or mixture of these copolymers is greater than 10, the tube obtained does not have acceptable resistance to stress cracking.
In other words, in order to obtain a tube which can be manufactured by the process of injection, in a single injection operation and having a permeability to water vapor and a resistance to stress cracking in accordance with the specifications defined in the preceding, a flexibility allowing evacuation of the product by simple pressure of the user and an ability to be fused by the so-called "hot air" or "heating grippers" methods currently used, the tube must consist of an ethylene-linear C4 to C10 olefin copolymer or a mixture of ethylene-linear C4 to C10 olefin copolymers having a fluidity index between 3 and 10 g/10 min inclusive and a density between 0.880 and 0.935 g/cm3. Preferably, the ethylene-linear C4 to C10 olefin copolymer or the mixture of ethylene-linear C4 to C10 olefin copolymers has a fluidity index between 3.5 and 9 g/10 min inclusive and a density between 0.900 and 0.930 inclusive.
Thus, for the purpose of optimizing the flexibility of the wall, by reducing its thickness, one formulates an ethylene-linear C4 to C10 olefin copolymer or a mixture of ethylene-linear C4 to C10 olefin copolymers having a fluidity index between 5 and 10g/10 min inclusive, and preferably between 5 and 9 g/10 min inclusive.
The minimum thickness of the wall being determined by the length of the skirt of the tube and the fluidity index of the material which is used, it has been found that with the ethylene-linear C4 to C10 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, that is to say having a relatively high fluidity index, the average thickness of the wall of the skirt must be chosen on the curve represented in Figure 2, as a function of the desired skirt length. Thus, the average thickness of the skirt tends towards a lower limit in the vicinity of:
-	0.45 mm for a skirt length close to 60 mm;
-	0.60 mm for a skirt length close to 90 mm;
-	0.75 mm for a skirt length close to 120 mm;
-	0.85 mm for a skirt length close to 150 mm; and
-	0.95 mm for a skirt length close to 200 mm.
This choice is particularly pertinent for large tubes or for materials of high density, because it allows one to minimize the stiffness imposed, either by the thickness induced by the flow length, or by the density of the material.
On the other hand, in the case in which one wishes to package creams containing highly surface active agents or in the case of tubes of low capacity inducing high weight loss ratios, one will preferably formulate an ethylene-linear C4 to C10 olefin copolymer or mixture of these copolymers having a fluidity index between 3 and 6.5 g/10 min inclusive, and preferably between 3.5 and 6.5 g/10 min inclusive, which obliges one to increase the thickness of the wall. In this case, the average thickness of the wall of the skirt must be chosen on the curve represented in Figure 3, as a function of the desired skirt length, in order optimize the flexibility of the tube. Thus, the average thickness of the skirt will tend towards a lower limit in the vicinity of:
-	0.55 mm for a skirt length close to 60 mm;
-	0.70 mm for a skirt length close to 90 mm;
-	0.83 mm for a skirt length close to 120 mm;
-	0.90 mm for a skirt length close to 150 mm; and
-	1.00 mm for a skirt length close to 200 mm.
The wall thickness values at mid-height of the skirt are given at +/- 0.05 mm in Figures 2 and 3 as well as in the preceding.
For the purpose of having very flexible tubes, when the impermeability constraints are low or when the ratio of evaporation surface area with respect to the volume is favorable, for example, for tubes whose skirt length is greater than or equal to 75 mm, one will formulate an ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers whose density will be between 0.880 and 0.920 g/cm , and preferably between 0.900 and 0.920 g/cm inclusive.
The tube will be even more flexible if it is injected out of an ethylene-linear C4 to10 olefin copolymer or mixture of these copolymers whose MFI is between 5 and 10 g/10 min inclusive, and preferably between 5 and 9 g/10 min inclusive, and whose density is between 0.900 and 0.920 g/cm3 inclusive, which allows one to choose the minimum wall thickness for a given skirt length.
A particularly preferred practical example of this solution is an ethylene-octene copolymer with a fluidity index between 5 and 6 inclusive and a density equal to 0.919 g/cm , for example, Dowlex 2035E.
Inversely, when one wishes to optimize the property of impermeability to water of the tube which is produced, while keeping an acceptable flexibility, one will choose an ethylene-linear C4 to C10 olefin copolymer or mixture of these copolymers having a density between 0.925 and 0.935 g/cm inclusive for an average wall thickness of the skirt close to 0.45 mm, between 0.920 and 0.930 g/cm inclusive for an average wall thickness of the skirt close to 0.60 mm, or between 0.915 and 0.925 g/cm3 inclusive for an average wall thickness of the skirt of 0.75 mm.
For example, in order to obtain a tube with reinforced impermeability to water vapor and with optimized flexibility as a function of the length and of the thickness average of the wall of the skirt, one will use a mixture of 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to C10 olefin copolymer with a density between 0.900 and 0.920 g/cm3 inclusive and 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to C10 olefin copolymer with a density between 0.920 and 0.935 g/cm3 inclusive. Modulation
of the composition of the mixture permits one to modulate the density and therefore to stabilize the flexibility of the wall as a function of its thickness, that is to say indirectly of the length of the skirt, the increased porosity being compensated for by the improvement of the ratio of the evaporation surface area with respect to the weight of contained cream, as disclosed in the preceding.
More precisely, in order to obtain a tube having at the same time a very good resistance to stress cracking and a very good barrier effect to water vapor, the flexibility being optimized as a function of the length and of the average thickness of the wall of the skirt, one will preferably use a mixture of 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer with a fluidity index between 3 and 6.5 g/10 min inclusive and a density between 0.900 and 0.920 g/cm3 inclusive and 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer with a fluidity index between 3 and 6.5 g/10 min and a density between 0.920 and 0.935 g/cm3 inclusive, the modulation of the composition of the mixture allowing one in the same way to stabilize the flexibility as a function of the wall.
As an example, the desired effect will be reached by using a mixture of 33 to 67 wt%, with respect to the total weight, of Dowlex 2035E with a fluidity index between 5 and 6 g/10 min and a density equal to 0.919 g/cm3 and 67 to 33 wt%, with respect to the total weight, of Dowlex NG 2429, with a fluidity index between 3 and 4 g/10 min and a density equal to 0.935 g/cm3.
More precisely, a mixture of 50 wt% of the first copolymer and 50 wt% of the second copolymer is more preferred because this mixture guarantees control of the amount measured in each injection and an optimized balance between weight loss and flexibility for tubes of small size. Thus, a preferred mixture according to the invention for obtaining a tube with a good resistance to stress cracking and a very good impermeability to water vapor with an acceptable flexibility will contain a mixture containing 50 wt% of each of the ethylene-actene [sic; octene] copolymers mentioned above.
In order to ensure the packaging of very highly surface active products, the fluidity index of the material is reduced into a limit greater than or equal to 3 and preferably 3.5. It is then preferable to use materials consisting of a mixture of 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to C10 olefin copolymer with a fluidity index between 3 and 4 g/10 min and a density equal to 0.935 g/cm3 and 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to C10 olefin copolymer with a fluidity index between 5 and 6 g/10 min and a density equal to 0.915 g/cm3. In this case also, preferably, one will use ethylene-octene copolymers. As a counterpart to the effect obtained, the flexibility of the wall is attenuated proportionally to the increase of its thickness.
Table 1 hereafter presents examples of implementation of the invention. The
are intended to illustrate the invention and not to limit it. In particular, in these examples, all the copolymers are ethylene-octene copolymers or ethylene butene or ethylene hexene copolymers. However, tests have been done with ethylene-linear C4 to C10 olefin copolymers giving similar results, the properties of flexibility, resistance to stress cracking and barrier to water vapor being modulated in the same manner as a function of the fluidity index and the density of the material as well as the thickness of the wall.
The characteristics and proportions of the copolymers used are given in Table 1 hereafter and also in Figure 1.
[Key to previous page:]
1	Example No.
2	Characteristics of the copolymer which was used
3	Characteristics of the tube obtained
4	Copolymer which was used
5	Number of C of the olefin (type)
6	wt%
7	Density
8	Density of mixture g/cm3
9	Result obtained
10	Use
11	- very good resistance to stress cracking
-	very good impermeability to water
-	stiffness at the limit of acceptability
12	- very good resistance to stress cracking
-	good impermeability to water
-	mediocre flexibility
13	- good resistance to stress cracking
-	moderate flexibility
14	- good resistance to stress cracking
-	good flexibility
15	- tubes with barrier effect and improved impermeability
-	preferably tubes of small size
-	comfort of use mediocre
16	- tubes with improved barrier effect, improved impermeability
17	- tubes with improved barrier effect, improved impermeability and good comfort of use
18	- tubes with improved barrier effect and moderate impermeability
-	improved comfort of use
-	preferably tubes of moderate length
1	- good resistance to stress cracking
2	- good resistance to stress cracking
-	moderate impermeability to water
-	very good flexibility
3	- moderate resistance to stress cracking
-	very great flexibility
4	- good resistance to stress cracking
5	- good resistance to stress cracking
6	- tubes with improved barrier effect and moderate impermeability
7	- tubes with improved flexibility
-	applicable to all sizes including tubes of great length
8	- for great comfort of use
-	tubes of large capacity
-	tubes for packaging weakly surface active creams with limited weight loss or limited duration of use
9	- tubes with improved flexibility
10	- tubes with improved flexibility
In prior art, the tube is injected into a mold as represented in Figure 4 and composed of an insert noted 4 in Figure 4, a cavity insert 5 in Figure 4, and a nozzle receiver 6 in Figure 4 in which injection nozzle 7 in Figure 4 fits, that is to say the channel through which the melted plastic material is led into the cavity insert defined by the nozzle receiver, the cavity insert and the insert. Under the effect of the very high injection pressure necessary for injecting the material in the wall thicknesses required for the flexibility of the tube, the insert has a tendency to bow towards the cavity insert. This results in a variable wall thickness and therefore in variable flexibility. Much more seriously, the decentering of the insert generates preferential streams of material during injection of the skirt, preferential streams which join together in "weld lines", these "weld lines" forming zones of lack of resistance to stress cracking.
A first injection mold for obtaining this result is that of the type represented in Figure 5. As seen in Figure 5, this mold has central part 8. Central part 8 of insert 4 has free end 9 in Figure 5 which rests centered on nozzle receiver 6.
In order to proceed with the injection of the material from central injection point 13 to the head of the tube, radial feed channels are created in free end 9 of central core 8. The feed channels 10 can be seen more clearly in Figure 7, which is an enlarged view of the part noted VII in Figure 5.
However, the use of this technique has the disadvantage of creating as many feed points of the skirt as the number of feed channels between the injection point and the head of the tube.
In effect, as represented in Figure 6, from the three channels 10, three independent feed streams of the skirt are created, which generate the creation of three independent sheets of material 11 in Figure 6 of the skirt, which are connected by weld lines 12 in Figure 6.
This process and this mold will now be described in reference to Figures 8 and 9. As represented in Figures 8 and 9, this process consists of placing the injection point noted 13 in a plane situated below the upper part of the head of the tube at point of connection A between feed channels 10 and the head of the tube.
By placing injection point 13 in a plane situated below the part at the top of the head of the tube at the point of connection A between feed channels 10 and the head of the tube, the stream of injected material travels a route characterized by an angle, noted a in Figure 9, less than 90°.
The injected material therefore strikes the side (vertical in Figure 9) of the upper part of the head of the tube, which, from point of connection A, promotes a circular flow path, represented by arrows 15 in Figure 8 and in Figure 10, which allows the reconstitution of an annular stream of the injected material and considerably attenuates the creation of weld lines on the skirt. Thus, a mold for implementation of the process of the invention will include cavity insert 5, stationary insert 4 having central part 8 of which free upper part 9 is in the shape of a reentrant cone with respect to the insert.
In order to facilitate reconstitution of a circular stream of material from the points of connection between the radial injection channels and the upper part of the head of the tube, there is an advantage in forming the widest possible line of connection between each radial injection channel and the upper part of the head of the tube in accordance with Figure 10.
Another solution which further improves the annular feed but which reduces the area of support of the insert at the nozzle receiver consists of bringing the total widths of connection of
the feed channels at the point of connection with the head of the tube to more than 25% of the perimeter of the upper part of the head.
In order to keep a maximum area of support of the insert at the nozzle receiver while maximizing the total widths of connection A of radial feed channels 10 with the head of the tube, it is advantageous to give the radial channels a width which increases from injection point 13 to point of connection A with the head of the tube, as shown in Figure 10.
The annular narrowing zone formed at the entrance of the upper part of the head of the tube after point of connection A of the radial channel and the wall of the tube reinforces the effect of annular spreading of the stream of material which is sketched in Figure 10.
Finally, central insert 8 can be made mobile in insert 4. This arrangement is advantageously used when one does not wish to connect a "reducer" end piece on the tube, reducer which is then constituted by the top summit wall of the head of the tube. This wall is injected after the injection of the skirt and without interruption, after movement of the central insert back proportionally to the desired wall thickness of the reducer. After this operation, one has a single-piece tube injected in a single operation, the reducer being produced in the form of a basin, free upper part 9 of central part 8 of the insert being designed in the shape of a reentrant cone, the basin having an external surface which is completely smooth up to the edge of the vertical side of the end piece, the cavity being designed without radial or circular unevenness, and the feed channels being designed in the form of hollows in the mobile part of the insert according to Figure 7.
Thus, the invention is in no way limited to the embodiments described and illustrated in
the preceding description and covers all embodiments falling within the scope of the invention as
1. A tube made up of a skirt and a distribution head, characterized by the fact that:
-	its wall is made of an ethylene-linear C4 to 10 olefin copolymer or of a mixture
of ethylene-linear C4 to 10 olefin copolymers having a fluidity index (MFI)
measured according to the ISO 1133 standard between 3 and 10 g/10 min,
and preferably between 3,5 and 9 g/10 min inclusive, and a density between
0.880 g/cm3 and 0.935 g/cm3 inclusive, and preferably between 0.900 and
0.930 g/cm3, by the fact that the skirt has a wall thickness at mid-height
between 0.30 and 1.00 mm inclusive, and preferably between 0.35 and 0.95
mm inclusive, and a length between 40 and 200 mm inclusive,
and by the fact that
-	the skirt and the distribution head are manufactured in a single operation of
injection in an injection mold, which has cavity insert (5) and insert (4), said
insert having central part (8) whose free upper end (9) and rests centered on
cavity insert (5) during the phase of iniection of the tube, from which it results
that the tube is flexible, resistant to stress cracking and impermeable to water
2.	A tube as claimed in claim 1, wherein in each sectional plane along the longitudinal axis of the tube, the thickness of the wall of the tube is constant.
3.	A tube as claimed in claim 1 or 2, wherein the ethylene-linear C4 to 10 olefin copolymer(s) is (are) ethylene-octene copolymer(s).
4.	A tube as claimed in claim 3, wherein the said end (9) is in the shape of a reentrant cone, and wherein the angles a between channels (10) and the vertical axis of cavity insert (5) are less than 90°.
5. A tube as claimed in either of claims 3 and 4, wherein the total widths of channels (10) at their zones of connection (A) with the end piece of the head of the tube represent at least 15%, and preferably more than 25% of the perimeter of this end piece.
6.	A tube as claimed in any of claims 3 to 5, wherein channels (10) have a width which increases from injection point (13) according to a centrifugal radial direction to their points of connection (A) with the end piece of the head of the tube.
7.	A tube as claimed in any one of claims 3 to 6, wherein the end piece of the distribution head has an annular zone of narrowing beyond the zone of connection (A) of channels (10) with the end piece of the head of the tube.
8.	A tube as claimed in any one of claims 3 to 7, wherein the central part (8) of the insert of the injection mold is mobile,and wherein the upper wall of the head of the tube is injected after movement of mobile part (8) back a distance which is proportional to the desired wall thickness.
9.	A tube as claimed in any one of the preceding claims, wherein the fluidity index of the ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers is between 5 to 10 g/10 min inclusive, and preferably between 5 and 9 g/10 min inclusive, and wherein the thickness of the wall at mid-height of the skirt is situated on the curve represented in Figure 2, as a function of the length of the skirt, + or - 0.05 mm,
in order to obtain a tube with improved flexibility.
10.	A tube as claimed in any one of claims 1 to 8, wherein the fact that the
fluidity index of the ethylene-linear C4 to 10 olefin copolymer or mixture of these
copolymers is between 3 and 6.5 g/10 min inclusive, and preferably between
3.5 and 6.5 g/10 min inclusive, and wherein the thickness of the wall at mid-
height of the skirt is situated on the curve represented in Figure 3, as a function of the length of the skirt, + or - 0.05 min,
in order to obtain a tube with improved resistance of stress cracking, particularly in the presence of surfactant products.
11.	A tube as claimed in any one of the preceding claims, wherein the
density of the ethylene-linear C4 to 10 olefin copolymer or mixture of these
copolymers is between 0.880 and 0.920 g/cm3 inclusive, and preferably
between 0.900 and 0.920 g/cm3 inclusive, in order to obtain a tube with
12.	A tube as claimed in claim 11, wherein the skirt has a length greater than or equal to 75 mm.
13.	A tube as claimed in claim 9 to 11, wherein the fluidity index of the ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers is between 5 and 10 g/10 min, and preferably-between 5 and 9 g/10 min inclusive, and wherein the density of the ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers is between 0.900 and 0.920 g/cm3 inclusive.
14.	A tube as claimed in claim 11, wherein the wall of the tube is made of an ethylene-octene copolymer with a fluidity index between 5 and 6 g/10 min inclusive and a density equal to 0.919 g/cm3.
15.	A tube as claimed in any one of claims 1 to 10, wherein the density of the ethylene-linear C4 to 10 olefin copolymer or mixture of these copolymers is
between 0.925 and 0.935 g/cm3 inclusive for a thickness of the wall at mid-height of the skirt close to 0.45 mm,
between 0.920 and 0.930 g/cm3 for a thickness of the wall at mid-height of the skirt close to 0.60 mm,
between 0.915 and 0.925 g/cm3 for a thickness of the wall at mid-height of the skirt close to 0.75 mm,
in order to obtain a tube with reinforced impermeability to water vapor and with optimized flexibility as a function of the thickness of the wall at mid-height and of the length of the skirt.
16.	A tube as claimed in claim 15, wherein the wall of the tube is made of a
a)	33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to 10 olefin copolymer having a density between 0.900 g/cm3 inclusive, and
b)	67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-linear C4 to 10 olefin copolymer having a density between 0.920 and 0.935 g/cm3 inclusive.
17.	A tube as claimed in claim 16, wherein its wall is made of a mixture of:
a)	33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 6.5 g/10 min inclusive and a density between 0.900 and 0.920 g/cm3 inclusive, and
b)	67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 6.5 g/10 min inclusive and a density between 0.920 and 0.935 g/cm3 inclusive,
in order to obtain simultaneously a tube with improved stress cracking with reinforced impermeability to water vapor and optimized flexibility as a function of the thickness of the wall at mid-height and of the length of the skirt.
18.	A tube as claimed in claim 17, wherein the fact that its wall is made of a
a) 33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 5 and 6 g/10 min and a density equal to 0.919 g/cm3, and
b) 67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 4 g/10 min an a density equal to 0.935 g/cm3.
19.	A tube as claimed in claim 18, wherein each ethylene-octene copolymer represents 50 wt% of said mixture.
20.	A tube as claimed in claim 19, wherein the wall of the tube is made of a mixture of:
a)	33 to 67 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 4 g/10 min and a density equal to 0.915 g/cm3, and
b)	67 to 33 wt%, with respect to the total weight of the mixture, of an ethylene-octene copolymer having a fluidity index between 3 and 4 g/10 min and a density equal to 0.935 g/cm3.
Dated this	9th	day of September, 2002.
in-pct-2002-01231-mum-cancelled pages(09-12-2005).pdf
in-pct-2002-01231-mum-claims(granted)-(09-12-2005).doc
in-pct-2002-01231-mum-claims(granted)-(09-12-2005).pdf
in-pct-2002-01231-mum-correspondence(28-03-2006).pdf
in-pct-2002-01231-mum-correspondence(ipo)-(13-04-2007).pdf
in-pct-2002-01231-mum-drawing(09-12-2005).pdf
in-pct-2002-01231-mum-form 18(04-03-2005).pdf
in-pct-2002-01231-mum-form 1a(09-09-2002).pdf
in-pct-2002-01231-mum-form 1a(09-12-2005).pdf
in-pct-2002-01231-mum-form 2(granted)-(09-12-2005).doc
in-pct-2002-01231-mum-form 2(granted)-(09-12-2005).pdf
in-pct-2002-01231-mum-form 3(09-09-2002).pdf
in-pct-2002-01231-mum-form 3(09-12-2005).pdf
in-pct-2002-01231-mum-form 4(25-10-2005).pdf
in-pct-2002-01231-mum-form 5(09-09-2002).pdf
in-pct-2002-01231-mum-form-pct-ipea-409(09-09-2002).pdf
in-pct-2002-01231-mum-form-pct-isa-210(09-09-2002).pdf
in-pct-2002-01231-mum-petition under rule 137(09-12-2005).pdf
in-pct-2002-01231-mum-power of authority(09-09-2002).pdf
in-pct-2002-01231-mum-power of authority(09-12-2005).pdf
IN/PCT/2002/01231/MUM
ZI DU TIENNON, F-63550 ST. REMY-SUR-DUROLLE, FRANCE.
1 GERY DAMBRICOURT LA VERCHERE-63300 ESCOUTOUX, FRANCE.
PCT/FR01/00800
1 00/03469 2000-03-17 France