FR2561575A1 - METHOD FOR MANUFACTURING THERMOPLASTIC TUBULAR CONTAINERS HAVING BARRIER PROPERTIES - Google Patents

Abstract

THE MANUFACTURE OF TUBULAR ARTICLES, IN PARTICULAR TUBULAR CONTAINERS, IS DESCRIBED. PREPARED BY EXTRUSION, COEXTRUSION AND OR LAMINATION, A THERMOPLASTIC POLYMER SHEET, COMPRISING ONE OR MORE DISCRETE POLYMER LAYERS, IS CUT INTO ONE OR MORE LAYERS WHICH ARE EACH HEATED AND WRAPPED ON A MANDRIN TO CONDUCT A POWDER. EACH WOUND TAPE ARE WELDED TO COMPLETE THE TUBE. THE TUBE IS CUT TO LENGTH AND PROVIDED WITH CLOSURES AT ITS END TO FORM A CONTAINER.

Description

PROCESS FOR MANUFACTURING THERMO- TUBULAR CONTAINERS

  PLASTICS WITH BARRIER PROPERTIES,

  The present invention relates generally to the fa-

  brication of thermoplastic containers and more particularly-

  processes for manufacturing plastic containers from several constituents. The usual containers are generally made of metal, glass, or

  paper-based composite material. Other containers used

  They are formed from plastics. The current

  invention more particularly applies to containers fa-

  made from polyesters and polyolefins. The reci-

  patients prepared according to the process of the invention replace those made from plastic as well as those made

  from glass, metal or paper.

  As part of the manufacturing of plastic bottles

  There are many ways to make them.

  One of these consists in producing a preform, also called "parison", by injection molding the molten plastic material in a parison mold, and letting it solidify. We then place this parison in a device

  extrusion-blowing which combines both the contribution of

  2 Core, air pressure and mechanical stretch to expand

  the parison in a bottle having its final shape.

  Generally, this process, which comprises two or three stages, is long and costly because of the time required and the equipment required for manufacturing, as well as

  The large amount of energy to be supplied to the polymer, for

  read its fusion during the injection molding step of the parison, and after cooling, during reheating for

the extrusion blow molding stage.

  Another method is to manufacture containers by a direct injection molding technique, by which a bottle is formed in a single mold, by direct injection of molten polymer into the mold to form the bottle having its final shape. This system, although eliminating

  the double heating of the parison technique has the

  advantage of not allowing the orientation of the polymer, which leads to a bottle of weak structure. Because of this lack of orientation, the polymer has only weak barrier properties, thus allowing oxygen to easily penetrate and leave

CO2.

  A third method for forming thermoplastic containers consists in extruding a tubular parison, in introducing it, while this tubular parison is still

  the molten state, in a mold and to carry out a blow-molding-

  flage to form the bottle in its final form. The desa-

  vantage of this method lies in the fact that one can give only a weak orientation to the thermoplastic material of the bottle, and that one also obtains a bottle whose

  some sections have a very weak structure, in particular

  tie the bottom of the bottle, where the joint is made.

  On the other hand, the manufacture of containers of the type

  box by conventional techniques is completely different

  different from that applied for bottles. The boxes

  composites are first made from cardboard, the extremi-

  tees, made of metal or plastic, then being glued on or placed

  embossed. The cylindrical parts of the box are generally serpentine using a strip of

  suitably shaped cardboard, the lower or upper ends

  of metal or plastic, being placed respectively

before and after filling.

  Improved manufacturing methods are described in 351st Belgian patent N 897,398 in the name of the Applicant (entitled -3

  "Thermoplastic container end, method and apparatus

  ge of inertial rotation of these container ends "), and in US patent N 4,386,999 (entitled" Rotational inertia welding of container ends to container bodies ").

  In these patents, it is taught that the ends of the

  boxes are fixed by rotation welding on

  the cardboard parts mounted in a serpentine.

  In US patent RE 29448 to Brown, there is described

  O10 means for attaching ends of thermoplastic material

  than on the tubular parts of the containers.

  In Belgian patent N 896.542 in the name of COSDEN

  TECHNOLOGY Inc., describes a method for fixing extremities

  tees in thermoplastic material on any form of tube, for

oscillation welding.

  The disadvantages of these methods, whether they relate to metal tubes with seals or cardboard tubes mounted in a spiral, are mainly their duration and their cost. So,

  both embossed metal tubes and core tubes

  spiral-mounted tones are prone to leaks. In addition, cardboard boxes should usually be covered with

  interior to prevent liquid infiltration through

  towards the wall. However, even covered, the boxes of car-

  Your disadvantage is that the fluid they contain

  in the box by the edge around the end

  lower, and siphone in the wall, or infiltrating event-

through the label.

  Other types of conventional boxes include flexible aluminum boxes. Although this type of container does not have joints at the bottom end and

  on the sides, the upper end must be placed by left-

  frage. However, the use of aluminum has become very expensive because it requires large energy expenditure to

  refine the metal, form it into sheets, and form the

  pients from the leaves. The upper extremity must be relatively thick and must be incised, and include a

  pull tab which is sealed thereon by welding or other means.

This too is too expensive.

  An improved method for forming bottles is described in European patent application No. 5126.575 of COSDEN TECHNOLOGY Inc., according to which the container is formed by thermoforming an upper end comprising a peripheral friction weld flange, by thermoforming d 'a lower end having a peripheral flange of friction welding and by extrusion of a cylindrical tube on which the lower ends are friction welded

and higher.

  The process described in said patent application

  identifies the continuous formation of a tubular body in single or multi-layer thermoplastic material, this tubular body being

  produced by extrusion or coextrusion.

  Although this method already constitutes an improvement over the prior state, the present invention still has significant advantages not only over the techniques

  conventional, but on the process described in said de-

  patent application. For example, in this process, each extru-

  deuse is limited to the formation of a single tube, which is a restriction. The present invention makes it possible to operate at a maximum throughput of the extruder by extruding large sheets and dividing it into as many strips as necessary.

  to use the whole sheet. Each strip is then formed

  méée in a continuous tube, which in a way gives a pro-

  5 to 10 times faster than that described in the

  European patent application no. 126.575.

  The process of the invention can also be used to manufacture tubes of non-cylindrical shape, for example having a square, rectangular or triangular shape, by means of different rollers and mandrels. It is also possible, with the process of the invention, to simultaneously manufacture tubes of

  different shapes, using different rollers and man-

  -5- drins on the different bands coming from the sheet of

thermoplastic materials.

  The object of the present invention is to remedy the

  above mentioned. The present invention relates to an apparatus and methods for forming containers

  thermoplastics without practically giving away waste,

  both to obtain excellent orientation of the polymer and good adhesion of multi-layer sheets comprising a layer

  fence. These advantages are obtained by extruding or coextruding

  in a sheet of multi-layered thermoplastic material

  taking a barrier layer, by orienting this sheet by a mono- or biaxial stretching, then by rolling up the sheet in one or more tubular sections which are cut to length and closed by bottoms and covers which are attached, by

  methods such as oscillation welding, tubular sections

laires.

  The process of the present invention for the manufacture of

  tion of thermoplastic articles having tubular parts is characterized in that it comprises the steps which consist in: - forming a sheet of a thermoplastic material having a predetermined thickness; cutting this sheet into at least one continuous strip of a predetermined width;

  - heat this strip to a temperature at which the material

  thermoplastic riau can be formed, - rolling this heated strip to form a tube; - seal the two edges of the strip together to form this tube; - cut sections of tube of predetermined length; and - provide at least one closed end for each section of

  tube for forming tubular articles.

  The present invention is also described with the aid of drawings in which: - Figures 1 and 2 are perspective representations of lines of sheet coextrusion; - Figure 3 is a schematic sectional view of a coextruded sheet during manufacture; Figure 4 is a side view of a coextrusion line and a sheet orientation device; - Figure 5 is a side view of an extrusion / co-laminating line; - Figure 6 is a top view of a container forming line, to be connected to the lines of Figures 4 and 5; - Figures 7 to 13 show a tube forming line, for use with Figure 6; - Figures 14 to 16 show a container made of material

  thermoplastic, bottle-shaped, which can be manufactured

  qué by the method of the invention;

  - Figure 17 shows a box of thermoplastic material

  as carried out by the method of the invention; - Figures 18 to 21 illustrate assemblies of rollers of different shapes; and

  - Figure 22 illustrates an axial view of another type of device

reil to weld the ends.

  Figure 1 is a perspective representation of a coextrusion line 110 in which a main screw extruder 112 is operationally connected by a tube

  supply 114 to a coextrusion supply unit 120.

  The extruder 112 can be a conventional extruder of

  screw type thermoplastic material. A second extru-

  Deuse 116, often called a coextruder, also feeds the power supply 120 through the feed tube 118. The

  112 and 116 extruders are chosen for their capacity to plas-

  to classify thermoplastic polymers such as polypropylene, polystyrene, polyethylene, polyvinyl chloride, polyethylene terephthalate (abbreviated as PET), copolymers

  ethylene and vinyl alcohol, and other similar plastics

  containers. The plasticized thermopolymer entering the feed block 120 from the feed tubes 35114 and 118 is distributed inside the feed block -7- in a predetermined manner and sent to the sheet die 122. This die 122 extends the thermoplastic, which

  is in the form of a generally tu molten current

  bular, in a relatively wide flat sheet through the outlet outlet orifice 124. The function of the power supply unit 120 is to separate and recombine different combinations of the two thermoplastic streams coming from the extruders 112 and 116, so that the sheet 126 extruded by the

  die 122 includes the desired combination of thermal layers

  plastics coextruded in a single sheet. The sheet co-

  extruded 126 then passes over cooling rollers 128, and 132 to solidify the sheet and allow it to be

  physically manipulated after coextrusion.

  Figure 2 shows a coextrusion line including

  taking a main extruder 112 and two coextruders 116 and 134. While the coextrusion line of Figure 1 is capable of producing two to four layers in a coextruded sheet by dividing and recombining the output currents of the two coextruders, the line of Figure 2 coextrusion is capable of extruding multilayer sheets comprising

  two to six coats. The addition of each additional extruder

  the coextrusion line therefore allows

  up to two additional layers in the extruded sheet.

  Each additional coextruder requires channels and

  additional distribution means inside block 120.

  According to a particular embodiment, the coextrusion line of Figure 2 is used to make a sheet with five layers. The main coextruder 112 produces a layer of

  base which is divided into two streams which will form the

  external polymer layers. One can coextrude by the second coextruder a layer of a polymer having barrier properties, like the ethylene-vinyl alcohol copolymer (abbreviated as EVOH), and one can use the third coextruder 134 (connected by the tube 136) to provide two layers adhesive

  to adhere the outer layers to the barrier layer.

  -8- We connect a sheet system 122, similar to that of the

  Figure 1, at the outlet of the power supply 120, and we enter

  tracks the multi-layer molten polymer in the form of a tubular stream, and this is spread out in a thin flat sheet 126 which is then cooled on the cooling rollers

128, 130 and 132.

  Figure 3 shows a schematic section of the

  leaf die 122 of Figures 1 and 2, which performs the coex-

  trusion of a multi-layer sheet 126 which is cooled by passing between the rollers 128, 130 and 132. The thickness of the

  coextruded sheet 126 is exaggerated to illustrate its composition

  multi-layered tion. In one embodiment, the sheet 126

  includes a base layer A on the outer surface of the film

  1c, which is preferably extruded by the primary extruder 112. A central barrier layer B is located exactly in the center of the coextruded sheet and is preferably extruded by the second coextruder. Two adhesive layers C are located between the barrier layer B and the outer layers A,

  these layers C being extruded by the coextruder 134. It im-

  indicates that the extrusion of layers A, B and C by the

  extruders 112, 116 and 134 actually refer to plastic

  solid polymer particles to form a coating

  rant molten, and that the final extrusion of molten current is carried out

  read in the die 122 after the molten currents come from

  of the three extruders have been combined in the block

supply 120.

  According to a preferred embodiment of the present in-

  Note, the base layers A were made of a container polymer such as PET, and the barrier layer B of a

  material such as EVOH. As PET and EVOH are relative-

  ment incompatible and do not adhere to each other, an adhesive layer C was coextruded between the barrier layer and the base layers. The composition of the adhesive layer C is based on polyvinyl acetate or on a copolymer of ethylene and vinyl acetate, such as the product manufactured by MITSUI -9 -9 CHEMICAL COMPANY OF JAPAN and known under the name of ADMER . You can also use the C X A (product sold by DUPONT

  CHEMICAL COMPANY) as an adhesive for EVOH and PET.

  According to a second embodiment, a multi-layer sheet was formed to manufacture containers comprising base layers A made of polypropylene with a barrier layer of EVOH, the adhesive layer being based on an adhesive sold by MITSUI CHEMICAL COMPANY OF JAPAN under the brand

MODIC.

  Figures 4 to 6 illustrate an embodiment of a coextrusion line and manufacture of containers according to

  the present invention. In Figure 4, the line of coextru-

  sion 110, comprising the main extruder 112 and the coex-

  extruder 116, feeds the power supply 120 and the die

  re 122. A coextruded sheet 126 passes through rollers re-

  coolers 128, 130 and 132 up to two gripping rollers 138. These rollers 138 constitute a friction traction system which keeps the sheet 126 taut after passing it through the rollers 128, 130 and 132. After the sheet 126 has come out of the rollers 138, it passes through a blaxial orientation device 140 comprising a conventional sheet orientation system. In a sheet orientation system, the sheet is heated to its optimal orientation temperature and stretched both laterally and longitudinally,

  then cooled, to give it reinforcement and properties

  optimal barrier tees. This is a conventional orientation system commercially available in the field of thermoplastics. Alternatively, the biaxial orientation device 140 can be placed between the cooling rollers

  and gripper rollers to eliminate the need for reheating

  iron the sheet. In this case, the temperature of the material leaving the lower cooling roller 132 is monitored,

  and the coolant passing through the cooled rollers

  sors is controlled very precisely, so that

  351e material leaving the roll 132 is exactly at the temperature

- 10 -

  optimal orientation erasure. Then, the material passes through the biaxial orientation device which grips the sheet by the three free sides and stretches it biaxially as much as possible to provide the optimal orientation. Finally, the stretched sheet is cooled while being kept stretched to prevent

  it does not retract and lose its orientation.

  In FIG. 6, the sheet leaving the orientation device passes through a cleaver 142 in which it is split into at least three primary strips, D, E and F. The sides X and Y of the main sheet which are cut from the strips primary D and F are recycled by passing them through a

  grinder and including them in an inner layer of the film

  via one of the coextruders. Each strip D, E and F then passes through a hot winding device 144, where each strip is wound and welded to form a cylindrical tube G, H and I. These continuous cylindrical tubes then pass through a first cutter 146 which cuts roughly the tubes in sections 147 of desired length. These sections 147 are

  stored in a basket 148, then pass through a second layer

  or they are cut to exact length with flat, smooth ends. These sections 151 of exact length are stored in a second tank 152, from which they pass one by one in an apparatus 153 for rotary welding as it is commercially available, and more fully described.

  2 in the American patent RE 29448 already cited above.

  In the rotary welding apparatus 153, container ends are brought by the conveyor 154 to be welded by rotation in the sections 151, thus giving containers such as those illustrated in Figures 3014 to 17. These containers are then stored in a hopper 156 and suitably oriented for passage through the device

  158 label printing. From device 158, the reci-

  finished customers pass through the conveyor 160 to the filling line with the solid or liquid food product which it

  is intended to contain. The 153 rotary welding apparatus

- l1 -

  tion and 158 printing are items available in the

  trade that can be acquired in the container industry

  pient. A preferred embodiment uses a rotary welding machine called AW-14 made by VERCON Inc., Garden Grove, California, and a VAN DAM printing machine

  manufactured and sold by VAN DAM USA, Camden (New Jersey, USA).

  Alternatively, and this is one of the many advantages

  According to the invention, a flatbed printing apparatus can be used to print the labels on the sheet before it is transformed into cylindrical tubes. This only requires the placement of a flat label printer

  just before or just after the cutter 142. The impression of label

  flat quilt is well known in the container industry;

  it is easier, faster and more precise than printing

  sion of labels on curved cylindrical surfaces. The

  present invention allows the flat printing of several labels

  bowls directly on the thermoplastic container walls

  plastic pieces before they are bent, a pro-

  yielded which until now had not been possible to achieve.

  The tube sections 151 are tubular sections

  cylindrical all the same length and which have been formed

  carried out by an apparatus 144 for hot winding and welding,

  after biaxial orientation of a sheet produced by coextru-

  if we. Figures 14 to 17 show that these tubular sections

  cylindrical can be transformed into cans or bottles

  the. In each of these cases, the bottom of the container

  mainly consists of a circular disc having a re-

  U-shaped edge for friction welding, pressure welding or bonding of the disc on the cylindrical tube. The upper part of the container may be either in the form of a bottle top, preferably made by injection molding, or of a box top consisting of a flat disc provided with an opening by tab, in each case provided with a rim in inverted U shape for fixing on the tube

- 12 -

  cylindrical. Figure 5 shows another embodiment of the container manufacturing line, in which one forms

  a multi-layer sheet, with a layer of a barrier polymer

  re or a metal attached to the inside or outside of the multi-layer sheet. A primary extruder 210 feeds a single layer power supply 212 and a die 214 to

  single sheet 222. A roll 216 of barrier material,

  preferably consisting of a polymer or metal sheet, is placed above and near the extruder 210. This sheet 218 passes over an spreader roller 220 and joins the

  sheet 222 at device 224 of cooled rollers

  sisters. A second extruder 226, with a power supply 228 and an extrusion die 230, sends a second sheet 15232 of polymer into the device 224. The two sheets of polymer 222 and 232 join the barrier layer 218 between the cooling roll upper 234 and the central cooling roller 236, and they are compressed there, then

  that they are still half softened by the heat,

  both in good adhesion between the two extruded layers and the barrier layer. The multi-layer sheet then passes over the final cooling roller 238 and emerges from the assembly 224 in the form of a multi-layer sheet material 240. This material passes through the assembly 242 of tension rollers, and from 251 to the cutter 142 and in the hot winding apparatus

144 of Figure 6.

  In the embodiment of Figure 5, if a metallic foil is used as barrier material 218,

  no orientation system should be used because the film

  Metal is not likely to be oriented. On the other hand, if the barrier material 218 consists of a thermopolymer such as EVOH, the biaxial orienter 140 can advantageously be placed either between the cooling rollers and the tension rollers or between the tension rollers and the cutter. As

  mentioned above, the biaxial orienter includes main-

- 13 -

  a mechanical drawing means which grips the two sides and the free end of the sheet and which pulls in the two axial directions of the sheet. The embodiment of Figure 5 therefore provides a multi-layer sheet comprising a barrier layer similar to that provided by the system of Figure 4 using a laminating system rather than a system

  coextrusion to adhere the layers together. The avan-

  tage of the multi-layer sheet production system of Figure 5 is that materials other than polymers can be included in the sheet. For example, a thin sheet

  metallic aluminum, tin or copper can be incorporated

  porée between layers of polymer maintained at a temperature-

  sufficient to ensure good adhesion to the metal foil. Alternatively, it is possible to use an i5coextruder in place of the simple extruder 210, giving a two-layer sheet, one being the container polymer and the other being an adhesive. Likewise, the second extruder

  226 can be replaced by a coextruder giving a sheet

  the two-layer consisting of a layer of polymer coated

  green with a layer of adhesive. The adhesive layers are placed

  so that they are inside when

  that they pass between the rollers 234 and 236 and therefore in con-

  tact with the 218 barrier material to provide good

  hesitation to the latter. This is particularly useful when

  s25on using a barrier material like EVOH which is not ai-

  highly compatible with polymers such as polypropylene or

  the fart. In addition to including a sheet between two layers

  ches polymers, the invention allows to include a barrier layer-

  re on which a label is printed between two layers

  of a transparent polymer like PET. This eliminates the need

  site to include a printer 158 in the middle or at the end of the

  container manufacturing line.

* Figures 7 to 13 describe a possible embodiment

  sible of an assembly 144 of hot winding and welding, shown schematically and not to scale to show

2S61515

- 14 -

  the general principle. Two series of coaxial parallel rollers guide the multi-layer sheet 126 and gently bend it,

  while it is heated to its glass transition temperature, to make it a cylindrical tube. In Figure 7, the parallel rollers 310 and 312 are generally flat. A second set of parallel rollers 314 and 316 is placed downstream of the rollers 310 and 312: in Figure 8, the

  rollers have a certain curvature which they print on foil

  126. FIG. 9 represents a semicircle of the sheet 10126 formed by the rollers 318 and a heated mandrel 320. On

  10, the sheet has acquired the shape of a cylindrical tube.

  only by the action of the rollers 322 and of the mandrel 320 which has become cylindrical. Figure 10 also shows a welding source consisting of a melting or heating source of any known type. For example, the heat source

  324 for welding can be a flame, a laser, a heater

  microwave, quartz heating or any other equivalent means. Alternatively, the welding source 324 can

  dispense or spray a molten thermopolymer in the place

  ment of the joint 125 of the sheet 126. Another embodiment of the welding process uses a quick-setting resin, such as an epoxy resin, or any other liquid adhesive or

  semi-liquid acceptable to join the two edges of the tube

rolled.

  The embodiment of Figure 10 shows a sou-

  lasts end to end. Figure 11 is a side view of the final stage of tube formation shown in Figure 10. Figure 12 is a schematic view of another embodiment

  the process of forming the tube, in which a seam is formed

  hard to overlap: one edge of the sheet overlaps the other edge during the course of the last tube forming step, and a roller 326 provides sealing pressure to form the cylindrical tube. Roller 326 actually consists of a series of rollers arranged axially along the weld surface of the tube, as shown in Figure 12. A source

- 15 -

  heat 324, placed upstream of the rollers 326, preheats the

  thermoplastic sheet at the place of welding. The sour-

  that of heat 324 can be of any usable type such as radiative or microwave type heating. The rollers 326 and Figure 13 are shown compressing the lap joint into a one-dimensional weld, by the gradual flattening of the superimposed part and in the semi-molten state until the section of the tube is completely cylindrical . Figures 7 to 13 therefore illustrate several

  modes of execution of the assembly 144 for forming the tube

shown in Figure 6.

  Figure 22 shows, seen from the side, a different type

  rent of welding equipment used in another embodiment.

  In this embodiment, the sheet 126 is wound around a cylindrical mandrel 320, as in the other embodiments already described, and the two edges of the sheet are brought against each other for welding. end to end. Fair

  before touching, the edges pass near a resistance

  heating element 330, such as for example a Ni-Cr wire, connected to an electrical supply (not shown). The passage

  edges near the heated wire bring them to their temperature

  then they are pressed against each other immediately

  soon after. This process gives excellent butt welds

  exhausted with minimal energy expenditure for heating.

  If necessary, the wire can be covered with an anti-

  adherent, for example polytetrafluoroethylene, for mini

  bet the adhesion of the polymer on the wire if they touch acci-

  dentally. Figures 14 to 16 show a type of container advantageously produced using the present invention. The

  bottle 401 has a tubular cylindrical wall 402

  read by the present process. A closure 404 in the form of a disc is friction welded, melted or glued below the tube 402, and a closure 403, formed from a bottle top, comprising a threaded neck 407 and a filling ring 409

- 16 -

  inco1porés, is fixed in the same way above the tube 402.

  The tubular part 402 is shown in FIG. 14 as a single-layer material, but FIG. 15 shows another embodiment of this part formed from a three-layer material 420, 422 and 420 produced by rolling and / or coextrusion. As mentioned above, the wall of the tubular section 402 can include any number of layers,

  between one and nine layers, using multiple coextruders

  multiple shown in Figures 1 and 2. Figure 16 is

1One cut along line 4-4.

  Figure 17 shows a use of the welded tube made according to the present invention to make a typical 502 box. The box is made of a welded tubular cylindrical section 502, to which are attached a lower closure 504 and an upper closure 503. The upper closure 503 comprises a pull tab 505 incorporated for

  open the container. As mentioned above, the closures

  res of bottle 401 and box 501 have a rim in

  U-shape for friction welding, gluing or fusing

  sion to the tubular section of the container. The closure may

  also be embossed or glued to the tubular part. Different-

  its combinations of these methods can thus be used.

  Figures 18 to 21 illustrate different configurations

  end of the rollers to obtain uniform tubes

  non-cylindrical with square section, rectangular respectively

  re, triangular or elliptical: Other polygonal shapes

  or curves can be formed in the same way, with the-

  which containers can be made using non-rotating welding techniques, such as oscillation welding, or

  3X using fusion and / or bonding by adhesion to the tubes.

  The present invention makes it possible to rapidly manufacture thermoplastic containers having barrier properties.

  and whose thermopolymer is oriented. The process of the invention

  tion converts the crude polymer granules into finished containers, with printed labels if desired. This process

- 17 -

  is relatively compact, and can be placed directly

  in the filling plant of the food processor.

  This process therefore eliminates the need to send the empty containers from a container manufacturing plant to the filling plant, this transport being uneconomical because of the volume of the empty containers. In addition, the invention makes it possible to manufacture containers quickly, efficiently, with good yield and a minimum of waste. The containers thus manufactured have cylindrical wall sections which can be made of a multi-layer material comprising a material formed by a polymer and / or a metal foil and which can also include oriented polymers which give better mechanical resistance while reducing the amount of raw polymer required. The container manufacturing process

  uses extrusion, coextrusion, rolling or a combination

  These methods are used to prepare the sheet which is then rolled up into welded tubes. The process allows the continuous production of a tube of polymeric material, which is then cut to length and closed at the ends to give finished containers. Using wide extruders which allow

  to extrude sheets 132 cm or more in width, a -

  single extrusion assembly supplies multiple lines

  tube manufacturing. Likewise, several lines of fabrica-

  tion of multi-walled tubes comprising a barrier layer

  can be supplied by a single coextrusion assembly.

  For example, a 122 cm wide multi-layered sheet

  taking a barrier layer can be extruded from a 132 cm coextrusion line comprising a primary extruder and a secondary coextruder; after division, this single sheet can supply several tube manufacturing lines which

  allow you to make boxes and bottles such that-

  glossed by Figures 14 and 17. The usual sizes of these containers are such that the necessary strip must be about 18 cm wide. Given the waste, it is therefore possible to cut the sheet into six to seven strips, and

- 18 -

  therefore feeding six to seven tube lines from a single sheet extruder. Therefore, although the method described in European patent application 126.575 is advantageous compared to the prior art, the present invention offers the additional advantage that several tube lines can be supplied from a single assembly extrusion thanks

  a cutter and tube welding systems.

  Although the present invention has been described using preferred embodiments, it is understood that they

  o10 do not constitute a limitation thereof, and that certain modifications

  The contributions made by those skilled in the art are an integral part thereof. For example, instead of rollers and a mandrel

  heated 320, it is obvious that two man-

  parallel drins or only rollers. Likewise, other types of welding, well known to those skilled in the art,

  can be used for tube assembly. Others form-

  my closures can also be used for the top and bottom of containers. Similarly, the cutting of the tubes to length can be carried out by various means such as

  laser cutting, sonic or with a hot knife, or

  re fast sawing. Other polymers than those described may

  can be used, such as styrene and acryl copolymers

  lonitrile, polyvinylidene chloride, and copolymers

ethylene and propylene.

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RE V E N D I C A T I O N S

  1) A method of manufacturing thermoplastic articles having tubular parts, characterized in that it comprises the steps which consist in: - forming a sheet of a thermoplastic material having a predetermined thickness; - cutting this sheet into at least one continuous strip of a predetermined width; - heating this strip to a temperature at which the thermoplastic material can be formed; - wind this heated strip to form a tube; - seal the two edges of the strip together to form this tube; - cut sections of tube of predetermined length, and - provide at least one closed end for each section of

  tube to form tubular articles.

  2) Method according to claim 1 characterized in that one

  forms sheets of at least two thermoplastic materials

  different, by melting thermoplastics

  in an extruder, so as to form layers

  crests of thermoplastic material, these layers being solid

duly fixed to each other.

  253) Method according to any one of claims 1 and 2,

  characterized in that the temperature of ex-

  leaf trusion above cutting temperature

  vitreous sition of the thermoplastic material, since the

  until the tube is formed.

  4) Method according to any one of claims 1 to 3,

  characterized in that a multilayer sheet is formed

  either by coextrusion or by rolling several curves.

  355) Method according to claim 4, characterized in that the multilayer sheet comprises at least three layers, of which

  an inner layer of a barrier polymer.

- 20 -

  6) Method according to claim 5, characterized in that the barrier polymer is chosen from the group comprising:

  ethylene-vinyl alcohol copolymers, poly- chloride

  vinylidene and styrene-acrylonitrile copolymers.

  7) Method according to any one of claims 1 to 6

  characterized in that a tube whose shape is

  chosen from a cylindrical shape or a non-cylindrical shape

drique.

  8) Method according to any one of claims 1 to 7

  characterized in that the closure end is attached to the tubes either by rotational welding or by welding

by friction.

  9) Method according to any one of claims 1 to 8

  characterized in that the edges of the tubes are sealed by thermal fusion, either end to end, or one above the other.

  ) Method according to any one of claims 1 to 8

  characterized in that the edges of the tubes are sealed by gluing.

  2511) Method according to any one of claims 1 to 10

  characterized in that the sheet is oriented in at least

  an axial direction, after forming of said sheet.

  12) Method according to any one of claims 1 to 11,

  characterized in that a label is printed on the sheet, after it has been formed and after the step

  orientation, but before winding.

  13) Method according to claim 4, characterized in that the multi-layer sheet comprises at least three layers including

  an internal layer constituted by a metallic sheet.

  14) Method according to claim 12 or 13, characterized in that a label is printed on an inner layer of

leaf.

- 21 -

  ) Method for manufacturing plastic containers, characterized in that it consists in - forming a single sheet having at least three layers of

  polymers linked together, at least one of which is

  killed with a barrier polymer; - cut this sheet into several strips of determined width; - heating the strips to a temperature higher than the glass transition temperature;

  - wind each strip, to form a continuous tube, au-

  turn of a longitudinal axis parallel to the edges of the strip, - seal the two edges of the strip together to form

  this tube, cut sections of tube of prede-

  finished, and leave at least one end closed at

  each section of tube to make containers.

  16) Method according to claim 15 characterized in that it further comprises the steps which consist in - orienting the sheet after its forming in at least one axial direction; - print a label on the sheet after having been formed and oriented, but either before or after the winding step. 17) Method according to claim 15 characterized in that

  the obturation is placed by friction welding.

  18) Method according to any one of claims 15 to 17,

  characterized in that a sheet is formed comprising five coextruded layers consisting of - two external layers constituted by a polymer; - a central layer constituted by a barrier material; two intermediate layers of adhesive material between

  each outer layer and the central layer.

- 22 -

  19) Method according to claim 18 characterized in that one of the outer layers is made of polypropylene, the other outer layer is of an ethylene-propylene copolymer and

  the barrier layer of an ethylene-viny alcohol copolymer

  lique. ) Method for forming containers characterized in that it comprises the steps which consist in - extruding a sheet comprising at least one layer of a thermoplastic material; - laminating at least one additional layer of a material on this extruded sheet, to form a single sheet with several layers linked together;

  - heat this multi-layer sheet to an in-

  lower than the melting temperature, but sufficient to obtain its softening; - cutting this sheet into at least one strip of predetermined width; - winding this strip to form a tube whose edges are parallel to the longitudinal axis of the tube formed; - seal the edges to form a continuous closed tube; - cut the sections of tube of determined length; - place at least one closure at each tube section

to form a container.

  21) Method according to claim 20 characterized in that a metal sheet is laminated on this extruded sheet,

  and add a second layer of thermo material

  plastic on this metal sheet.

  22) Method according to any one of claims 20 and 21,

  characterized in that the layers are linked together by

heating or bonding.

  23) Process according to claim 20, characterized in that

- 23 -

  a sheet comprising at least two layers is coextruded

  of different thermoplastic polymers.

  24) Method according to any one of claims 20 0 23

  characterized in that after forming, the sheet is oriented biaxially. ) Apparatus for manufacturing plastic tubular articles, characterized in that this apparatus comprises a device for plasticizing a thermoplastic resin, a die ir fixed to this plasticization device, for transforming this plasticized resin into a sheet, a device / cutting

  page to cut this sheet at least one contiguous strip

  bare sheet material having a desired predetermined width, rollers for winding this strip of sheets into a continuous tube, a sealing device for

  seal two parallel edges of this tube together, a provision

  sitifd6dcoupageto cut a predetermined length under-

  haitable from this rolled and sealed tube and, a device for

  attach thermoplastic closures to the ends of these tubes.

  26) Apparatus according to claim 25, characterized in that

  this plasticizing device comprises an extruder.

  27) Apparatus according to claim 26, characterized in that it

  further includes a coextruder connected to this wire.

  28) Apparatus according to claim 25, characterized in that it further comprises a device for adding at least one additional layer of material to this rear sheet

Faculty.

  29) Apparatus according to claim 28, characterized in that it further comprises a device for adding a barrier layer and a label layer to this extruded layer

behind this sector.

  ) Apparatus according to claim 25, characterized in that this sealing device comprises a heat device

- 24 -

  to melt the edges of the sheet together with heat.

  31) Apparatus according to claim 30, characterized in that this heat device comprises a welding device

butt-end.

  32) Apparatus according to claim 31, characterized in that

  this welding device comprises a heated wire.

  33) Apparatus according to claim 30 characterized in that

  this heat device includes a support device

sealage.

  34) Apparatus according to claim 25, characterized in that this device for fixing the closures at the ends

  includes a friction welding device.

  ) Apparatus for manufacturing thermoplastic containers from thermoplastic resins, characterized in that

  this appliance includes a heat device for

  quer mechanical energy to a solid thermoplastic resin to melt this resin, a die for extruding this molten resin in a device for manufacturing

  continuous sheet to cool this sheet, a dispo-

  sitive to form a barrier layer on this sheet, a device for transforming this sheet into at least

  a predetermined strip of desirable width, a provision

  tif for winding this strip into a tubular form, a device for sealing together the edges of this wound strip to form a continuous tube, a device for cutting sections of tubular container of length

  desired predetermined from this tube and a disposi-

  tif to fix thermoplastic ends to this tube

to form containers.

  36) Apparatus according to claim 35, characterized in that

  the heat device comprises a mechanical extruder.

  37) Apparatus according to claim 36, characterized in that

- 25 -

  this device for forming a barrier layer comprises a coextruder attached to this die parallel to this extruder. 38) Apparatus according to claim 37, characterized in that

  this sector includes a coextrusion sector.

  39) Apparatus according to claim 35, characterized in that this barrier layer forming device comprises an assembly of bitter rolls sheets to apply one or more additional sheets of material on

  this sheet continues behind this die.

  40) Apparatus according to claim 11, characterized in that it further comprises a label printing device

  between this cooling device and this

roll.

  41) Container manufacturing system for manufacturing containers

  barrier thermoplastic tubular contents, characteristic

se in that this system includes:

  a main extruder for melting waste materials

  thermoplastic sine, a coextruder has parallel

  to this main extruder to melt a

  thermoplastic barrier polymer, a coextru-

  sion attached to these extruder and coextruder to form

  a multilayer thermoplastic sheet, a release device

  cutting to cut / ette sheet at least one strip

  a sheet of sheet material, a roller for winding each continuous strip into a continuous tube, a welding device for welding together the adjacent edges of this wound tube, an Etube cutting device for cutting desirable lengths of the tube from this welded tube continuous and, a friction welding device for welding thermoplastic closures in at least

  one end of each length of tube.

- 26 -

  42) Apparatus according to claim 41, characterized in that it comprises a roller landing system: secondary for applying an additional layer of material to this thermoplastic sheet. 43) Apparatus according to claim 41, characterized in that

  it includes a label printing device available

dried downstream of this sector.

  44) Apparatus according to claim 43, characterized in that this label printing device is suitable for printing flat labels on this sheet when it leaves this die,) Article comprising a thermoplastic body, characterized in that it comprises: a tubular wall part comprising a strip of rolled and sealed thermoplastic sheet and at least

  a terminal closure in this part of the tubular wall

  airtight, sealing the end of the latter.

  46) Article according to claim 45, characterized in that this wall part comprises a multilayer strip of

  thermoplastic sheet with at least one layer of poly-

  structural mother and at least one layer of bar polymer

  These layers are joined together in a single sheet. 47) Article according to claim 45, characterized in that this wall part further comprises a layer of

  metallic sheet bonded between two polymer layers.

  48) Article according to claim 45, characterized in that

  this terminal closure includes a thermo-closure

  plastic welded by friction to this part of the tubular wall. 49) Article according to claim 45, characterized in that it further comprises a second thermoplastic closure

* - 27 -

  friction welded to the opposite end of this part

of tubular wall.

  50) Article according to claim 45, characterized in that this part of the tubular wall is cylindrical and comprises a joint parallel to the longitudinal axis of this part of the wall. 51) Article according to claim 45, characterized in that this part of the tubular wall is not cylindrical and comprises a joint parallel to the longitudinal axis of this

wall part.

  52) Article comprising a container having a multilayer body, characterized in that this container comprises a sheet of extruded thermoplastic resinous material to which is

  bonded a sheet of barrier material, this multi-sheet

  ticouche being formed in a tubular section by winding-

  ment and welding parallel to the longitudinal axis of the tube and this tubular section having at least one closure

  tightly attached to one end thereof.

  53) Container according to claim 52, characterized in that this barrier material comprises a layer of resin

  barrier coextruded with this thermoplastic resinous material

  tick. 54) Container according to claim 52, characterized in that

  this barrier material comprises a layer of metallic foil

  metal laminated to this thermoplastic resinous material.

  ) Container according to claim 52, characterized in that in addition it comprises / a layer with printed label attached to

this tubular section.

  56) Container according to claim 52, characterized in that it further comprises a layer with printed label

  laminated between two sheets of this resinous material

extruded plastic.

- 28 -

  57) Container according to claim 52, characterized in that it further comprises a label printed directly

  on this sheet of thermoplastic resinous material.

  58) Container according to claim 52, characterized in that it further comprises a label printed directly

  on this sheet of barrier material.

  59) Container produced by the process comprising the steps of forming a continuous sheet of thermoplastic resin, making a continuous sheet of barrier material adhere to this resin sheet, cutting this multilayer sheet

  glued in at least one continuous strip of predeter width-

  undermined, wind this strip in a tubular configuration,

  glue the edges of this tubular strip together, uncovering

  for this tubular strip in desirable lengths

  predetermined and fix at least one closure to an ex-

  end of each length of tube.

  ) Container according to claim 59, characterized in that this step of forming the sheet comprises the extrusion of

  the sheet through an extruder and a die.

  61) Container according to claim 59, characterized in that

  this bonding step comprises the coextrusion of the thermoplastic resin material and a thermoplastic barrier material to

  through coextruders in a block

  multilayer feed and a die.

  62) Container according to claim 59, characterized in that this bonding step comprises the bonding of a barrier sheet to this extruded sheet after this sheet

extruded has been extruded.

  63) Container according to claim 62, characterized in that

  this bonding step includes the use of an adhesive.

  64) Container according to claim 62, characterized in that

  this bonding step includes heat fusion.

- 29 -

  ) Container according to claim 62, characterized in that

  this barrier sheet comprises a metal sheet.

  66) Container according to claim 62, characterized in that

  this barrier sheet comprises a barrier resin.