Title of Invention	A PROCESS FOR PRODUCING PACKAGING TUBES OF PLASTIC MATERIALS
Abstract	In the manufacture of plastic tubes from prefabricated tube body portions with heads welded thereto. wastage occurs in the form of tubes with discoloured heads. heads with streaks or run-marks and defective welds. In accordance with the invention the wastage is avoided by retarding the heat flux in the tube-forming tool.

Full Text

Process for prnducing packaging tubes Packaging tubes are characterised in that a tube head with closure iS mounted to a tube portion, rpferred to as a tube body portion. Tube body portions are produced Inter alia hy extrusion of plastic materials or shaping and welding of the longitudinal edges of foil strips in web form consisting of weldable plastic materials. For the purposes of fitting tube body portions (hereinafter referrpd to as body portions for the sake of brevity) with tube heads (hereinafter referred to as heads for the sake of brevity), essentially two processes have gained acceptance, more specifically eguipping the body portion with prefabricated heads and forming heads on a body portion after the production thereof, wherein the forming operation can be divided into two procedures, more specifically forminq by 1njection moulrii ng and pressing. What is common to those alternative procedures is a bar or mandrel which carries the body portion to be provided with the head, the body portion being pushed onto the bar or mandrpl. A further common aspect to the three alternative procedures are sO-Called female moulds or dies into which bars or mandrels with body portions thereon are introduced, for attaching the heads. In the procedure for equipping the body portions with prefabricated heads, the heads are accommodated in the dies - this situation involves receiving means which hold heads in positioned relationship - and. after the introduction of the bar or mandrel with the body portion, the'latter is welded along its inner periphery to the outer periphery of the head, with the application of heat. In that procedure, a peripherally extending inner strip at one end of the body portion is brought into engagement with a peripherally extending outer edge portion of the head. For the welding operation, the amount of heat that is reguired for that purpose is to be so sufficient that the material of the body portion and of the head melt to such an extent that they flow into each other to form the weld In the forming procedure using injection moulding, the bar with body portion (for the sake of brevity, the bar or mandrel is referred to hereinafter as the male mould portion) is introduced into the female mould portion which is of a configuration corresponding to the shape of the head. whprein after the male mould portion has been so introduced, the mould cavity forming the head, with the end of the tube body portion projecting thereinto, is filled with liquid plastic material with .the application of pressure to the liquid plastic material, and in that case the end of the tube body portion is joined to the injectable plastic material by being fused onto same. In the press-shaping procedure of the third mode of manufacture, in which shaping of the head and the arrangement of the body portion on the head are effected during the pressing operation, the female mould portion or die which again Is of a configuration corresponding to the shape of the head is loaded with a portion of plasticised plastic material which is put into the appropriate shape by the die and the bar or mandrel with the tube body portion during the introduction of the bar or mandrel, with the application of pressure to the head, with an end of the body portion and the head being simultaneously joined together, wherein the pressure is set by introduction of the bar into the die, against the resistance of the portion of material therein. Those three operating procedures have been developed to a high technical level and each involve certain Individual advantages and disadvantages in terms of procedure, and this also applies in regard to the products manufactured in accordance therewith, that is to say tube body portions provided with heads In spite of the high state of development of the known processes, they only afford a limited degree of reliability, appropriate to their state of development, in regard to freedom from faults or defects in the products produced in accordance with those processes. The most frequent product defects are shadows, streaks or run-marks and discoloration of the head, defects involving an aesthetic effect, and defects in the head/body portion join which prevent a tube from functioning as a reliable and sound container. Those product defects can be attributed to the thermal content of the tools, which it is difficult to keep constant " a female mould portion or die and a male mould portion are referred to as a tool ^ . in particular durinq prolonged production times, with a high level of output of tubes per unit of time, In order to counteract the effects of fluctuating thermal contents. technically complicated and expensive cooling and heating devices are used for the tools, and such devices reduce the percentage of dpfective tubes in a production batch, but they do not bring that percpntaqp down to zero. That "zeroing", that is to say "zero-defect" production, is something that is unreservedly sought in connection with packaging tubps as mass-produced items, as a result of the wide ranges of use thereof and the necessarily large reject amounts, when there is just a small number of defective tubes, and there is no lack of endeavours and developments directed at attaining that aim. However, with the presentday high level of development the comparatively high level of expenditure for process developments which are specifically directed in that way is unsatisfactorlly related to the results that can actually be achieved. With that background in mind, the object of the present invention is to develop the known processes, that is to say the process for providing tube body portions with prefabricated tube heads, and the head forming process, while avoiding a comparatively high level of development expenditure, using simple means, in such a way as to move towards zero-defect manufacture. That object is attained by means of a process having the characterising features of claim 1. The invention deviates from the prevailing teaching for the optimisation of production reliability and guality insofar as. instead of being concerned with accurate adjustment and preservation of the thermal contents of female mould portions or dies and male mould portions with the expensive means which a re requ i red for that purpose. the invention i s directed to a simple basic setting of the thermal contents (heating, cooling) with certain, intentionally permitted degrees of fluctuation, combined with a heat flux barrier between the female mould portion or the male mould portion, durinq the oppration ot mounting the head on the tube body portion or forming the head on the tube body portion. In the case of the process according to the invention, the heat barrier replaces the expensive, complicated means and measures necessary for the known processes, for setting the thermal contents of the tools and for keeping said thermal contents constant. ,If the external surface of the head is denoted as the surface which faces towards a closure of an outlet or nozzle of the tube and the internal surface of a head is denoted as the surface which faces towards the interior of the ttibe body portion, a heat barrier can be provided between the external surface of a head and the surface, corresponding thereto, of the female mould portion, or between the internal surface of the head and the corresponding surface of the bar or mandrel. In both cases, the heat barrier can be connected to or not connected to the external or the internal surface. In the case of heads which are formed on the tube body portions, the heat barrier may also appear between the head surfaces, that is to say. it may be formed into heads. In all cases, the heat barriers fundamentally, that is to say with varying degrees of success, satisfy the function attributed thereto, namely taking the level of manufacturing reliability and quality to a high level, that is to say into the close proximity of zero-defect manufacture in regard to discoloration and/or defective welds. Normally a tube head comprises a shoulder with an outlet or nozzle projecting from the shoulder. It has been found to be substantially sufficient, for the purpose according to the invention, for the heat barrier to be arranged in the form of a heat barrier covering part of the respective area involved, on the bar or mandrel surface which shapes or corresponds to the internal surface of the shoulder. Instead of heat barriers being provided over part of the area involved, they may also be provided over the full dred in question. In that case, the heat barrier would cover over the surfaces of the bar or mandrel, which form the internal surface of the shoulder and the outlet or nozzle. Heat barriers can he permanently or replarpably arranged on the above-Indicated shaping surfaces of the bar or mandrel. The replaceable arrangement is preferred, that is to say. using a new heat barrier, for example in the form of a round portion or disc, for each shaping operation. When using round portions or discs which are preferably joined to the surface of the head after the shaping operation, the round portions or discs enjoy a high degree of freedom in terms of design configuration, which can be to such an extent that the outlet or nozzle opening is covered by means of the round portion or disc, in the manner of a closure The material used for the heat barriers can be any material whose ignition point is above the working temperatures of the tool and the material of the head and which exhibits thermal conductivity such as to delay the heat flux between the female mould portion and the male mould portion during the operation of providing the tube body portion with a head (finished head with heat flux from fusion of the material therearound. that Is to say welding) or forming the head on the tube body portion (injection moulding, press shaping), and that delay in the heat flux may be either from the female mould portion to the male mould portion or vice-versa, depending on the direction in which the heat flux occurs. In addition, insofar as a heat barrier is disposed on the Inward side or sides of the head, the material of the heat barrier must be resistant to the packaging substance which is env1saged for being contained 1n the tube. For packaging materials which are not of superior quality, for example technical greases, the material used can be paper and papers which are lined with plastic material, with a relatively high inflammation temperature (ignition point). Banners comprising plastic material foils (including plastic material foils coated with inorganic substances, referred to as CBL), have proven themselves to be desirable for packaging materials such as cosmetics and pharmaceuticals, in which case the plastic materials must be compatible with those of the heads, either by virtue of adhesive or fusion thereto insofar as a connection between the head and the heat barrier is desirable. Other advantageous heat barriers dre heat 1 barriers comprising laminate foils, for example an aluminium foil lined on both sides with a plastic foil (referred to for brevity as ABL. Aluminium Barrier Laminate, that is to say plastic laminate with an aluminium barrier layer), or a plastic foil, for example of polyethylene terephthalate (PET), lined on both sides with a plastic foil (referred to for brevity as PBL. Plastic Barrier Laminate, that is to say plastic laminate with a plastic barrier layer). It also applies for laminates that the material of the lining must be compatible with that of the head, that is to say it must be capable of being connected thereto, if a connection is wanted, in which respect compatibility also includes the capacity of the material of the barrier or a lining layer to withstand the packaging material in the tube. Polyethylene or polypropylene are preferably considered as the material for the lining. PET is desirable as a foil material for plastic monofoils, as the starting material. It was found that methods of manufacturing the heat barriers from materials of the above-mentioned kind have a not inconsiderable influence on' the barrier performance and characteristics, Basically, stamped flat discs as barriers which are matched to the shape of the shoulder during the connecting operation (welding or forming) by the tool and the filling thereof exhibit a sufficient barrier action. Flat barriers have a tendency to form folds during the forming operation, with the folds reducing the barrier effect. In order to counteract the effects of the folds or the formation of folds, barriers can be subjected to a deep-drawing operation, being formed in their definitive configuration. Barriers produced in that way are fold-free and the tool and the filling material remain free of shaping forces during the connecting procedure. In the case of barriers which are formed in that way, the effect thereof is good, provided that they are processed as required immediately after manufacture. What is to be avoided In connection with barriers of this kind is the "memory effect", that is to say the endeavour on the part of the barrier after shaping to return to its original shape, in which case the differences in dimension and shape which occur in that way cause fluctuations in the otherwise good barrier effect. While the stamping of barriers in disc form is effected separately from the connecting procedure and it is therefore possible to operate from stock, operation from stock gives rise to problems in regard to deep-drawn barriers because of the memory effect, and it is advantageous for the operation of deep-drawing a disc to be integrated into the entire product 1 on procedure for a tube. at a suitable1 ocation. for example upstream of the tool. The formation of folds and the memory effect are avoided 1n the case of barriers which are produced by vacuum shaping. Those barriers exhibit very good barrier effects and a very high level of constancy in terms of their operation. Those barriers can be produced as stamped flat barriers within or outside the overall production procedure, that is to say, it is possible to operate on barriers from direct production or from stock. For the vacuum shaping procedure a certain degree of heating is inevitable for each shaped body, and. prior to processing, the shaped bodies would have to be cooled down again approximately to ambient temperature. The manufacturing methods of stamping, deep-drawing and vacuum shaping dre preferred when using papers and foils of the above-described kind. However, heat barriers can also be produced in the form of finished components by injection moulding or press shaping, for example from PET (polyethylene terephthalate) and can be introduced into a prefabricated head or into or onto a tool for forming the head on the tube body portion, for the purpose according to the invention. A heat barrier or insulation effect of adequate extent is achieved if the internal surface of a heat barrier covers the shaping external surface of the male mould portion, in accordance with the preferred configurations of the heat barriers, by bearing thereagainst. In that respect, the dimension of the internal surfaces is not to be smaller than the corresponding dimensions of the external surface of the male mould portion, Oversizes in regard to the dimension of the internal surface of a heat barrier, in relation to the pxternal surface of a male mould portion, of the order of magnitude of 0,01 mm to 0.25 mm. preferably of the order of magnitude of 0.02 mm to 0.15 mm. can be tolerated without adversely 9 affecting the mode of operation of the heat barriers according to the invention. Thus, besides the barrier being tightly welded to the tube body portion, this also provides that, upon displacement of the barrier relative to the male mould portion, for example eccentric displacement of the barrier or if the barrier floats up in the material of the head during the operation of forming same, there are no excessively large regions without a heat, barrier effect. Normally prefabricated heads and heads which are formed on a tube body portion are of wall thicknesses of from 0.8 mm to 2 mm. In the case of heads involving wall thicknesses of that dimension, heat barriers of cellulose materials (paper, lined paper), plastic foils including laminates and prefabricated barriers (injection moulding, deep^ drawing and vacuum shaping) of wall thicknesses (thicknesses) of from 100 to 400 µm (0.1 mm to 0.4 mm), preferably from 125 to 250 µm (0.125 mm to 0.250 mm) have been found advantageous. Further advantageous configurations of the process according to the invention as set forth in claim 1 are recited by means of characterising features of the claims following claim 1. Further advantages, features and details of the invention will be apparent from the following description of a preferred embodiment of the invention and the drawing in which: Figure 1 shows a first embodiment of a tube end on a male mould portion, partially in axial section, with a plate-shaped disc in the shoulder part of the head of the tube. Figure 2 shows a further embodiment as illustrated in Figure 1 in which the plate-shaped disc overlaps a front tube body portion. Figure 3 shows a further embodiment as illustrated in Figure 2 in which the plate-shaped disc has a hollow-cylindrical extension, Figure 4 shows a further embodiment as illustrated in Figure 3, wherein the hollow-cylindrical extension is provided with a membrane Figure 5 shows a further configuration as illustrated in Figure 4. in which the hollow-cylindrical extension engages through a discharge or outlet opening to close same, and Figure 6 shows an apparatus for carrying out the process, as a partly sectional side view. In Figures 1 to 5 (the same parts are denoted by the same references in Figures 1 to 5). reference 10 denotes tube body portions which are only illustrated in their respective head end region and which, together with the heads generally identified by reference 11. form part of a respective packaging tube. The tube body portion 10 and the head 11 are illustrated in Figures 1 to 5 in the condition of being connected together on a male mould portion 26 (bar or mandrel of a tool). The tube body portion is formed for example from a three-layer PBL laminate whose barrier layer 12 comprises for example FVAC (ethylene-vinyl-alcohol copolymer) or PETP (polyethylene terephthalate). with the latter being clad, that is to say lined. on both si des wi th 1 ayers 13 and 14 of for exampl e PE (polyethylene). The head 11 itself comprises polyethylene and is produced for example by press shaping, that is to say by pressing a blank comprising plasticised polyethylene, wherein during the shaping operation the end 19 of the tube body portion is joined to the head 11 by partial fusing and melting into the head 11. The head 11 is formed from a shoulder portion 15 and an outlet or nozzle 16 with an outlet opening 17, wherein the outlet or nozzle 16 carries on its external surface, engagement means for a tube closure, for example a screwthread. As shown in Figure 1. provided as a heat barrier is a plate-shaped or tray-shaped disc 18 (also referred to as the heat barrier 18) which rests on the shaping surface (end face) of the male mould portion 26. that is to say the surface which shapes part of the shoulder 15. wherein the heat barrier 18 extends at one end from the end 19 of the tube body portion and at the other end as far as the entry opening of the nozzle or outlet 16. Figure 2 shows an advantageous development of the heat barrier illustrated in Figure 1. insofar as at one end it projects over and covers the end 19 of the tube body portion, which is introduced into the shoulder portion 15. while at the other end it extends as far as the entry opening of the nozzle or outlet 16. While, in the structure shown in Figure 1. the shaping end face of the male mould portion 26 1s partially covered over by means of the disc 1R as the heat barrier, in the embodiment shown in Figure 2 the end face is completely covered to provide a heat insulat-lon or barrier effect when forming the head and/or when welding It to the tube body portion 10 Referring to Figure 3. in an advantageous development of the invention the plate shapfed or tray-shaped disc 18 is provided with a hollow-cylindrical extension ?fl which extends around the outer periphery of the cylindrical mould portion forming the outlet or nozzle opening, in projecting relationship from the male mould portion 26. and thus curbs the heat flux through the cylindrical mould portion. In order to completely cover the front shaping end of the male mould portion 26. in a further advantageous configuration of the invention the hollow-cylindrical extension 20 has a cover portion 21 which engages over the end face of the cylindrical mould portion (which forms the outlet or nozzle opening 16). to cover that end face With this configuration, the entire surface of the shaping end of the male mould portion 26 is covered with a heat barrier 18. Advantageously, the heat barriers 18 remain in their shape in the head 11 after shaping of the head 11 and remain connected to the interior of the head 11. In this embodiment the cover portion 21 serves as a closure membrane which extends across the nozzle or outlet opening 17. That cover portion 21 is to be removed when a filled tube is used for the first time. In order to make it easier to remove the cover portion 21. a development of the cover portion 21 provides that it carries a hollow-cylindrical extension 22 with a closure end portion 23 into which engages the part of the male mould portion 26 that forms the outlet or nozzle opening 17. After the shaping operation the closure end portion 23 projects from the end face of the nozzle or outlet 16 (by about 0,2 mm to 0.3 mm) and can thus be more easily cut off to open the outlet or nozzle opening 17. Figure 6 shows a turntablp 28 with a tool, partly in section, after loading of the horizontally extending bar or mandrel 26 (male mould portion) with a tube body portion 10 and a heat barrier 18. Reference 29 denotes a fixed shaft about which the turntable 28 is rotatably mounted and drivable stepwise by means (not shown). The die or female mould portion 27 which has the mould cavity 25 is let into and fixed in the turntable 28. The mould cavity 25 corresponds to the external boundary contour of the tube head 11. Disposed beneath the die 27 and coaxially with respect thereto is a further die portion 24 in which a further mould cavity 25a is arranged for forming the screwthread on the tube head 11. A punch or plunger 31 which is loaded in the axial direction by a spring 30 is axially displaceably mounted in the further die portion 24. The punch 31 is loaded by the spring 30 in the direction of the mould cavity 25 and is pushed back against the force of the spring 30, when the bar or mandrel 26 is introduced into the die 27. The punch 31 serves to keep open the tube opening in the operation of pressing the tube head 11. The die portion 24 is rotatable about a further axis in order to release the screwthread of the tube head 11 when in the finished pressed condition. For that purpose it is rotated by means (not shown) or, in place of a rotary movement, it is opened by other means (not shown). The bar or mandrel 26 is arranged pivotably about an axis 32, The pivotal movement is produced by a pivoting device which for example includes a toothed rack 33 which engages with its teeth into the tooth arrangement on a pivoting member 35, The toothed rack 33 is connected to a push rod 36 which is axially slidably mounted in two mounting brackets 37. 38 which are fixed on the turntable 28. Between the mounting brackets 37. 38 the push rod 36 is rigidly connected to an antralnment member 39 having a guide roller 40 which is guided in a guide groove 41 of a cam disc 42 which is stationary, like the shaft 29. The guide groove 41 is of such a configuration in the cam disc 42 that the entrainment member 39 reciprocates between the mounting brackets 37, 38. whereby the bar or mandrel 26 is pivoted by way of the described means into a vertical position (pressing) or a hori/onlal position (loading, unloading). Reference 53 denotes a bar or mandrel carrier which carries the male mould portion 26. The carrier 53 is mounted longitudinally slidably under the force of a spring 52 on a cylindrical guide 51. When the bar or mandrel 26 is pivoted about the axis 32 into the vertical position, a forward feed means (not shown) acts on the roller 51 and displaces the male mould portion with tube body portion ]0 and a barrier 18 into the mould cavity 25 which in the present case is loaded with a plasticised portion of material (not shown), wherein upon termination of the shaping and welding procedure, the spring 52 moves the bar or mandrel 26 out of the female mould portion 27. .At "its front free end 43. the bar or mandrel 26 shown in Figure 6 is of such a configuration that the free end 43 (end face of the bar 26) can form the inside contour of a tube head 11. In that case, the projection portion 44 forms the through-flow opening of the outlet or nozzle of the tube head 11 while the inclined portion 43 adjoining same forms the inside surface of the shoulder of the tube head 11. The process according to the invention takes place in the following fashion in the apparatus as described hereinbefore by way of example. Disposed in a horizontal position, the bar or mandrel 26 is firstly loaded with a tube body portion 10 by a loading device (not shown), the loading operation involving the body portion 10 being pushed onto the bar 26. The body portion 10 is pushed onto the bar 26 until the end face 43 of the bar 26 remains free, that is to say a free end of the body portion 10 coincides with the transition of the surface 45 to the outer periphery of the bar 26. After the bar 26 is loaded, a heat barrier 18 1s put onto the end face 43 of the bar 26 by means of a further loading device (not shown). Heat barriers 18 may each be of one of the configurations described and illustrated in Figures 1 to 5, That two-part loading procedure may also take place 1n the reverse sequence, After the bar 26 has been loaded with the tube body portion 10 and the barrier 18. the bar 26 is pivoted into a vertical position and introduced into the die or female mould portion 27. that is to say into the mould cavity 25 in the die 27. Before the pivotal movement and introduction of the bar 26 into the die 27. the die 27 is loaded with a portion of plasticised plastic material. for example polyethylene. The amount of that portion of material is such as to correspond to the overall volume of a head 11. During the operation of introducing the bar 26 into the mould cavity 25. the head 11 is press-shaped by the contour of the mould cavity 25 and 25a (outward side of the head) and the end face 43 with barrier 18 applied thereto (inward side of the head), with the application of heat and pressure, while at the same time, that is to say during the operation of shaping the head 11. the body port 1 on 10 is fused to the head 11. After the forming and fusing (connecting) operations have been effected, a cooling step is effected to solidify the head 10 and the welded seam between the head 10 and the body portion 11. During the forming step, the connecting step and the cooling step, there is a heat flow from a higher heat level (generally that of the die 27) to a lower heat level (that of the bar 26) which is restricted by the barriers to such an extent as to avoid streaks or run-marks, colour defects and defective welds. In that respect, it is sufficient if the flow of heat is limited for a short period of time, preferably during the shaping procedure and the operation of fusing the body portion 10 into the head 11. After cooling of the tube, that is to say the head 11 formed on the tube body portion, the bar 26 is moved vertically out of the die 27 and pivoted into the horizontal position and the finished tube is removed from the bar 26 by a removal device (not shown). As described hereinbefore the process according to the invention is a 1 so effected i n conjunction with formation of the head by means of injection moulding. With that method of producing the head, the male mould portion and the female mould portion form the head-forming mould cavity into which liquid plastic material is injected under pressure. During the injection step, the tube body portion is connected to the head as it is being formed. The plastic material (for example polyethylene) is injected in a liquid condition, that is to say in a hot condition, into the female mould portion and the male mould portion with the tube body portion carried thereon. In this case also there are the problems of streaks and run- marks, discoloration and defective welds, which are avoided if the heat flux is throttled by means of a heat barrier. Defects of the above-described kind also occur when providing a tube body portion with a prefabricated tube head, 1f the tube body portion is connected to the prefabricated tube head by means of heating one or both components involved in the connection. When using that method of tube production. It has also been found advantageous to arrange a heat barrier between the end face of the bar and the inside surface of the prefabricated head, to suppress the above-indicated manufacturing defects. Arrangements of heat barriers dunng the procedure for attaching a head (finished heads) and during the procedure for forming a head on the tube body portion (injection moulding or press shaping) were illustrated hereinbefore. When attaching the head to the tube body portion, the heat barrier means can be applied to the bar or mandrel or put into the tube shoulder, before the body portion and the head of the tube are connected together. It may be desirable, during the procedure for injection moulding a head to give the finished head on the tube, to inject a heat barrier for example on the inward side of the head, or to provide a finished head with a heat barrier by insertion thereof. 1. A process for producing packaging tubes of plastic materials by providing prefabricated tube body portions with heads or forming heads on prefabricated tube body portions by means of a tool including a female mould portion and a male mould portion, in which a head is preshaped in the female mould portion or introduced thereinto as an amount of material to be formed which corresponds to the head and after introduction of the male mould portion with the tube body portion fitted thereon the body portion is connected to the head or the head which is in the course of being formed, with the application of heat and possibly pressure, characterised in that the connection is made with the introduction of a heat barrier means into the tool. 2. A process according to claim 1 characterised in that the connection is made with the introduction of a heat barrier means between an end face of the male mould portion and the preshaped head. 3. A process according to claim 1 characterised in that the connection is made with the introduction of a heat barrier means between a shaping end face of the male mould portion and the amount of material which is to be changed in shape by press shaping. 4. A process according to claim 1 characterised in that the connection is made with the introduction of a heat barrier means between a shaping end face of the male mould portion and the amount of material which is to be shaped by injection moulding. 5. A process according to one of claims 1 to 4 characterised in that a plate-shaped disc is applied as a heat barrier to the end face of the male mould portion in a condition of at least partially covering same. 6. A process according to one of claims 1 to 4 characterised in that a plate-shaped disc is applied as a heat barrier to the end face of the male mould portion in a condition of completely covering same. 7. A process according to claim 5 or claim 6 characterised in that a plate-shaped disc is applied, with a hollow-cylindrical extension surrounding an extension part of the male mould portion, that forms the outlet opening. 8. A process according to claim 7 characterised in that a plate-shaped disc with a hollow-cylindrical extension with a cover portion closing the extension is fitted. 9. A process according to one of claims 1 to 8 characterised in that plate-shaped discs comprising paper, lined paper, plastic monofoils or laminates (ABL, PBL. CBL) are fitted. 10. A process according to one of claims 1 to 8 characterised in that plate-shaped discs with a dimension in respect of their inside surfaces no smaller than the corresponding dimensions of the outside surfaces of the male mould portion with oversizes of the inside surfaces relative to the dimensions of the outside surfaces of the male mould portion of the order of magnitude of from 0.01 mm to 0.25 mm. preferably 0.02 mm to 0.15 mm. are fitted. 11. A process according to one of claims 1 to 10 characterised in that stamped, flat discs are arranged on the male mould portion. 12. A process according to one of claims 1 to 10 characterised in that deep-drawn, shaped discs are arranged on the male mould portion. 13. A process according to one of claims 1 to 10 characterised in that vacuum-shaped discs are arranged on the male mould portion. 14. A process according to one of claims 1 to 10 characterised in that discs produced by injection moulding or press shaping are arranged on the male mould portion. 15. A process according to claim 1 characterised in that heads with heat barriers disposed therein or injection moulded thereon in the finished head are connected to the tube body portion. 16. A process for producing packaging lubes of plastic materials, substantially as herein described, with reference to the accompanying drawings.

Documents:

1870-mas-1998-abstract.pdf

1870-mas-1998-claims filed.pdf

1870-mas-1998-claims granted.pdf

1870-mas-1998-correspondnece-others.pdf

1870-mas-1998-correspondnece-po.pdf

1870-mas-1998-description(complete)filed.pdf

1870-mas-1998-description(complete)granted.pdf

1870-mas-1998-drawings.pdf

1870-mas-1998-form 1.pdf

1870-mas-1998-form 26.pdf

1870-mas-1998-form 3.pdf

1870-mas-1998-other documents.pdf

abs-1870-mas-1998.jpg