FR2539074A1 - METHOD OF MANUFACTURING CONTAINERS - Google Patents

Abstract

The present invention relates to a method of manufacturing containers. The method consists in separately forming the upper part 103 of the container by injection molding or by thermoforming of a thermoplastic plastic material, the bottom part 104 and the middle part 102 or cylindrical body, then in welding the upper part by rotation. 103 and the bottom portion 104 to the cylindrical body 102. The invention is, for example, usable for the manufacture of plastic bottles. (CF DRAWING IN BOPI)

Description

The present invention relates to a method of manufacturing

  thermostatic polymeric material containers In the method described, multiple components of containers are used, which are welded to each other by rotation with formation of the final container. More particularly, the invention relates to a

  method of manufacturing plastic containers

  only from several components.

  Conventional container manufacturing methods typically involve forming metal, glass or paper-based composites into container shapes. Other common techniques include plastics.

  present invention relates to this field of technology.

  using thermoplastics and

  more particularly to polymers, such as poly-

  Esters and polyolefins The containers made according to the method of the present invention replace those produced by the usual techniques for shaping plastics as well as those in use.

glass, metal, and paper.

  Several methods are known for manufacturing plastic bottles. One of these methods consists in producing, in a mold, a preform (or pamison) by injection molding of a molten plastic material, allowing the preform to cool, then placing it in a blow molding apparatus or, by the combined effect of heat, air pressure and mechanical stretching, the finished bottle preform is expanded. Generally, this multi-step process is long and expensive, it requires high investment

  and requires a large expenditure of energy The fusion of the poly-

  mother to mold the preform by injection, followed by cooling and reheating for the molding by

  blowing requires a great deal of heat.

  Another method of manufacturing plastic containers consists of direct molding by injecting molten polymer, liquid, is injected directly into a mold having the shape of the desired bottle This technique does not require the double heat input the pre-formed method, but it does not allow to obtain an orientation of the polymer, so that the bottle has a very weak structure In addition, due to the lack of orientation of the polymer, the barrier effect against the oxygen input and the output of C 02

is very weak.

  A third method of container production

  thermoplastic material consists in extruding a

  its tubular that is enclosed in a mold, while it is still in the molten state, to bring it to the final shape by blowing This method still has drawbacks: the bottle has only a very small orientation and, in addition, it has weak portions in the bottom section where the seal is formed during blowing. The object of the present invention is to overcome the drawbacks of prior methods of producing

  bottles and other plastic containers.

  According to the method of this invention, the different components are separately formed in the most economical way, and then joined together, by rotational welding, into a solid and aesthetic container. An embodiment consists in forming the container by thermoforming the upper part or head part having a threaded neck and a cylindrical wall, thermoforming the bottom part, then extruding a cylindrical body to which the head part and the bottom part are welded by rotation. upper parts can fit into each other

even for bottom parties.

  Features and other peculiarities of

  the invention will emerge from the description of a mode

  implementation, given below with reference to the accompanying figures which show respectively: -3-

  Figure 1 is a sectional side view of a container

  by the method of the invention; Figure 2: a side view, in section, with greater échefle, of the upper part of the container of Figure 1; Figure 3 is a side view, in section, on a larger scale, of the bottom portion of a container; Figure 4 is a top view, in section, on a larger scale, of the conductive ring with lugs of the upper part of Figure 2; Figure 5: a side view, in section, of a bottom of

  container encased on an upper part.

  FIG. 6 is a sectional elevational view of the thickness of the three-layer wall of the container. FIG. 1 shows a container in the form of a bottle 101. This bottle comprises a cylindrical central portion 102 in the form of a cylindrical tube, which is

  welded to the upper portion 103 'and to a bottom 104.

  The upper part 103 generally consists of a slightly conical cylindrical section 105, a shoulder section 106 and a threaded cylindrical neck 107 with a helical thread 108 for the closure cap.

  109 is formed around the neck 107 and overflowing the latter.

  This ring 109 makes it possible to suspend the bottle at the filling machine during the introduction of the contents into the

  In addition, this ring 109 includes a series of erasers

  Peripheral drivers allow you to engage the

  upper part in the rotating welding mandrel.

  The central section 102 is generally tubular,

  cylindrical, preferably formed by extrusion or coextrusion

  trusion in its final form The cylinder is cut by any

  appropriate medium, such as a hot or laser blade, to

  The embodiment shown in FIG. 1 shows that the wall of this cross-section 102 contains only a single polymer sheet. However, according to another embodiment of the invention, the embodiment shown in FIG. the central section 102 is formed by coextrusion-of

  several layers, as shown in Figure 6.

  These layers may be 3 or 5 and they comprise inner and outer layers meeting the standards for food products, while the central layer acts as a barrier, and is for example ethylene-vinyl alcohol copolymer, in order to prevent the introduction of oxygen into the bottle or the loss through the wall of C 02 from the contents of the bottle Other layers may also be between the barrier layer and the inner and outer layers, for example layers

  adhesive to bind the other layers.

  The bottom section 104 includes a generally circular diaphragm closure having a relatively flexible central portion 110, a diaphragm 111, and a rotational welding flange 112.

  U, turned up, around the circumference.

  The upper section 105 also has a similar U-shaped but U-shaped rotational welding flange 113. These U-shaped flanges 112 and 113 are of such dimensions that they can fit snugly. , the cylindrical body 102 of the

  container It may be preferable that there is an adjustment

  Interference between the flanges 112 and 113 and the cylindrical body 102, which will give the heat of fusion when the three sections of the container are welded by rotation As mentioned above one can manufacture

  the container 101 from a polyester or a poly-

  olefin In one embodiment, the

  polyethylene terephthalate (PET) content This polymer meets the standards for the use of plastics in the food industry and has certain advantages, particularly with regard to clarity, strength and its effect properties. On the other hand, this PET polymer can be reinforced by orientation, that is, by stretching at the orientation temperature. The central body 101 is preferably formed into a single tube. solid PET layer, ie a coextruded multilayer tube obtained from a circular coextrusion die According to a preferred embodiment, five polymer layers are coextruded with the formation of a cylindrical tube One successively has a PET outer layer, then an adhesive layer, a layer of barrier material, for example a copolymer of vinyl chloride and vinylidene chloride or of ethyl copolymer. vinyl alcohol does, an adhesive layer and finally an inner layer of PET: These materials can be co-extruded simultaneously into a multi-layered cylindrical tube using a spider without nozzle, as described in U.S. Patent

No. 4,249,875 to the applicant.

  Figure 4 is a sectional view of the upper part of the bottle 101, taken along the line 4-4 of Figure 1, and shows more particularly the structure of the striated ring 109. to which is integrally attached the peripheral ring 109, which projects outwards

  of the surface of the neck 107 over a significant distance.

  A series of lugs 114 are formed symmetrically to the outer circumference of the ring 109 and project radially outwardly. These lugs 114 are particularly adapted for engagement with a rotational welding mandrel for rotating

the upper part 105.

  Referring again to Figure 1, a notch 116 is seen in the wall of the

  flange 112 and the lower end of the wall 102.

  This notch serves as a location for printing a label on the container and ensures that the preferred surface of this label will be in an outward facing direction when the container is placed in secondary packaging, for example in a package containing six containers This constitutes a

  important aspect from the point of view of the sales market.

  6- For example, it is particularly interesting for container beverage sellers that each container in the package has a label, most of which is outward looking; in this way, when the packaging is placed in a supermarket, the characteristics of the eye-catching label are visible to the buyer. Therefore, the cutting of the notch 116 at the bottom edge of the container allows, when filling of the container, to place the label so -que, when packing by 6 containers

  filled, the notch can be used to orient the

  during packaging and thus the attractive part

  the eye of the logo is facing outwards in the

packing for.

  Another way of proceeding is to form a location, such as a lug or protuberance at the top 103, rather than a notch 116 at the

flange 112.

  It is also possible to provide a protuberance or a lug inside the diaphragm 111 of the bottom 104, which

  not visible from above or from the side of the container 101.

  The particular mode of location of the notch 116 represents

  According to the preferred embodiment, for secondary packaging reasons the notch 116 allows easy orientation of the bottle when the secondary packaging has a lug which engages in the notch and makes it possible to orient the bottle. , the commitment

  an arm in the notch 116 gives additional support

  keep the container in the package.

  Figure 2 shows a view of the upper part of

  105 of the container in three parts before welding

  at the central part 102 This view shows that these

  In Figure 2, a second upper portion 105 is shown in phantom, which shows the possibility of interlocking the upper portions. This is particularly important in the manufacturing process. large-scale containers Several containers can be manufactured in one place and sent to another location for filling In the case of 1 or 2-liter bottles, known until now, they are usually made in one piece

  and transported empty to the filling site.

  Normally, a wagon-or truck loaded to full capacity empty bottles, in one piece, carries only about 1/20 of the transportable normal weight, because it carries air around With the present invention, one transports the different components of the bottle, nested in each other as shown

  Figures 2 and 3, which seriously increases the efficiency of

  FIG. 3 illustrates the interlocking of the bottom portions 104, showing in partial section a bottom portion 104 in which another

  bottom part shown in broken lines.

  FIG. 2 shows the saving of space resulting from the technique of the present invention. If we consider the distance on which the upper part, drawn

  in broken lines, comes from another

  105, in solid lines, in which it is nested, it can be seen that the nested part occupies an additional space which is approximately one-third of the original space of this part. The bottle manufacturer can therefore carry a larger number of parts.

  superior, interlocked, and eco-friendly

  nominate about two-thirds of the normal volume

  used for transport Similarly, we can fit the parts

  104 background to save space.

  In addition to the savings thus made, mention should also be made of the fact that the central part 102 of the container, consisting of a cylinder

  coextruded, can be manufactured at the filling

  Bottle aging Just send polymer particles, which is very interesting from the point of view

  space saving, and these particles are easily trans-

-8-

  formed in cylindrical tubes by extrusion.

  Therefore, the design of the containers according to the present invention allows a significant saving of the transport costs of the empty containers, as well as an improvement of certain characteristics notably the resistance, of the empty container coming from

  of the manufacturing technique by rotational welding.

  Figure 5 illustrates another mode of execution

  the bottom part of the three-part container.

  This bottom portion 204 has a peripheral flange

  The central portion 210 has a re-entrant cylindrical shape, adapted to receive the neck of another container. This neck 107 has a cap 115 fastened with a net closure. The lower shoulder 213 of the central portion 210 has dimensions such that it comes into contact with the ring 109 of a bottle placed below The central portion 210 of the bottom 204 makes it possible to stack the filled bottles during storage or placing it on the display, this stack being stable and making it possible to present the products

  Attractively containers used up to

  such as glass bottles or plastic bottles made from parasons, had the disadvantage of being unstable and unable to be stacked without placing intermediate sheets between each layer of containers. Therefore, a dealer wishing to exhibit stacks of these products had to devote time and money to placing these intermediate sheets through the present invention, and the use of bottles with central portion 210 serving as a receptacle at the bottom of each bottle, the neck 207 with cap 115 can enter this receptacle 210 of a filled bottle, the

  weight is supported by the ring 109 of the flat bottle.

below.

  The upper part 103 and the lower part

25390? '4

  104 or 204 can be manufactured using the usual injection molding techniques. However, it is advantageous to employ the technique described in the French patent application 8214925 in the name of the Applicant, and which has several advantages in particular.

  compared to previous methods.

  that a single sheet or a multi-layer sheet of polymer (s) is heated to a temperature higher than that of orientation and is applied to the sheet of air at medium pressure, which makes the sheet penetrate downwards in a pre-forming mold with the formation of a pile There is some cooling

  and the polymer is returned to its orientation temperature.

  At this moment, a strong air pressure is applied through the pre-form, which makes the sheet go up in a final mold where it takes its configuration.

  definitively by stretching, which gives it an orientation

  which can not be obtained with injection molding processes By applying this technique, higher and lower

  containers with optimum strength and characteristics

  This barrier effect can be improved by using a coextruded sheet to fabricate the top and bottom portions, thereby comprising a barrier polymer layer between two polymer layers, such as PET. A beverage container or the like will normally be made using the three parts described with reference to FIGS. 2 to 5. More particularly, the top portion 105, which has been formed by injection molding or thermoforming, and having a welding flange 113 for rotation, directed downwards, is

  placed in an upper rotational welding mandrel.

  The cylindrical portion 102, formed by extrusion or blow molding, is placed in the mandrel of the rotational welding apparatus. The bottom portion 104 or 204, with flange 112 facing up, is placed in

  the lower rotational welding mandrel

  this, the central mandrel containing the central portion 102 is stationary, while the upper and lower mandrels are rotatable When the three parts are placed in the respective mandrels, is rotated

  very quickly the upper and lower chucks.

  These two mandrels can rotate in the same direction, but it is preferred to rotate them in opposite directions to compensate for tensions when

  the preselected rotation speed is reached-

  speed which depends on the plastic used and the importance of the interfering clearance in the flanges

  112 and 113-, the upper and lower parts are printed

  re a fast movement compared to the central part,

  which forces the walls of this central part to penetrate

  trench in U-shaped flanges and cause melting

  of plastic This results in a hermetic seal

  that net and tenacious in these flanges 112 and 113.

  The resistance of the circles formed by the rotational welding joints to the flanges 112 and 113 contributes to the overall strength of the containers. Moreover, the shoulders of these flanges 112 and 113 protect

  the area reserved for the label on finished containers.

  When a label is glued or printed on the central body 102, the annular flanges 112 and 113 come into contact with each other.

  with the corresponding flanges of adjacent bottles

  tes, which avoids any friction or scraping of the label attached to the central body The label is thus protected, which is important for the dealer On the other hand, the central part is often lengthened, which gives a label surface that is greater than with the

  bottles used until now.

  In addition, the technique of the present invention makes it possible to manufacture containers with an external surface

  improved to receive the printed and / or painted label.

  For example, in the case where the tubular central part il-102 is obtained by coextrusion, one of the layers of the coextruded cylinder, and in particular the outer layer, may be a semi-porous, white, opaque material, such as polystyrene, impact resistant polystyrene, polyvinyl chloride, polypropylene, the surface is particularly suitable for color printing

alive by usual methods.

  The upper part 103 of the bottle may be made of a solid, clear material, such as PET, which is

  attractive for consumers and makes it easy to see

  Likewise, the lower part or the bottom 104 may be of a material giving the maximum of characteristics desired by the one who fills the bottles.

  use a low-cost material such as polystyrene

  or polystyrene impact resistant to the bottom 104, which limits the cost of the container The use of

  different materials depends mainly on their compatibility.

  For example, the contact surfaces in the flanges of the upper 103 and lower 104 portions must be compatible for rotational welding with the outer and inner surfaces of the central portion 102.

  compatibilities and can therefore make substitutions.

  The description given above relates to the production

  according to the technique of the present invention, but this technique can be used for

  make beverage or food boxes

  these boxes being used only once.

  In this case, instead of an upper part with neck 103, the container has a circular upper part, relatively flat, closing the box This upper part has a clip, which can easily be lifted and pulled to open the box La upper part can be welded by rotation to the part

  cylindrical center 102 instead of the upper part

  103 shown in the accompanying figures.

  12 - Modifications and improvements can be made to the execution modes described above, without

  depart from the scope of the present invention.

13 -

Claims (19)

claims:   A method of producing a container for liquid products, which container has a barrier material against gas transmission through its wall, which method is characterized in that a top portion is formed from a thermoplastic plastic material with closure means and a cylindrical wall section a cylindrical body portion is formed from a laminated thermoplastic material having at least one hard Elastic material layer to which at least one layer of barrier plastic material adheres, forming a bottom portion from a thermoplastic plastics material, said top, body and bottom portions being of compatible materials for rotational welding, and the upper part and the   bottom to the cylindrical body by rotational welding.   Method according to claim 1, characterized in that the upper part and / or the bottom part are   formed by thermoforming or by injection molding.   3 Method according to any one of the claims   1 and 2, characterized in that the body portion is coextruded into a multi-layered tube of which at least two layers are linked.   4 Method according to any one of the claims   1 to 3, characterized in that the body portion is coextruded with a cylindrical coextrusion die in at least three layers, which comprises an inner layer and an outer layer of hard thermoplastic material and a core layer bonded to both and a thermoplastic material with low gas permeability, especially ethylene-vinyl alcohol copolymer, polyvinylidene chloride, copolymer of   vinyl chloride and vinylidene chloride.   Method according to any one of the claims   14 - 1 to 4, characterized in that the upper part and the bottom part are polyethylene terephthalate, polypropylene, polyethylene, polyvinyl chloride or polystyrene.   6 Method according to any one of the claims   1 to 5, characterized by subjecting the body portion to an orientation before spin welding by stretching it while at its orientation temperature   Method according to any one of the claims   1 to 6, characterized in that the upper part comprises a U-shaped rotational welding flange facing downwards and the bottom part flange is in U shape turned up.   8 Method according to any one of the claims   1 to 7, characterized in that the extrusion of the section   cylindrical tubular consists of co-extruding this   in at least three layers, comprising an inner layer and an outer layer of a first thermoplastic material, and a core layer of a second thermoplastic material between the other two layers.   9 Method according to any one of the claims   1 to 7, characterized in that the extrusion of the cylindrical tubular section consists in co-extruding this section into five layers, comprising an inner layer   and an outer layer made of a first thermo-   plastic, a central layer of a second thermoplastic material, and a layer of adhesive between this central layer and each of the inner and outer layers. Method according to claim 1, characterized in that it comprises: forming a laminated thermoplastic polymer sheet having an inner layer and a structurally resistant polymer outer layer and a core layer of a low gas permeability polymer, forming the part upper and bottom portion of this polymer from this sheet, coextruding a cylindrical tube having an inner layer and an outer layer of a polymer compatible with the resistant polymer of this upper portion and said bottom portion, and a central layer made of a polymer with low gas permeability,   cut this coextruded tube to a predetermined length   completed, and to form the cylindrical body portion, rotatably weld this upper portion and this bottom portion to this tube to form a complete container. 11 Method according to claim 7 characterized in that the outer layer of the cylindrical body portion is polystyrene, polystyrene impact resistant,   polypropylene or polyvinyl chloride.   12 Method according to any one of the claims   1 to 11 for the production of a container in the form of a bottle, characterized in that it comprises: the injection molding of an upper part of a thermoplastic polymer, this upper part having a threaded neck and a wider cylindrical part forming a wall, the extrusion of a cylindrical tubular section of thermoplastic polymer which is cut to a predetermined length, 9 forming a circular bottom portion having a flange adapted for rotational welding to this circular section, and   rotational welding at this circulating section   re, and the rotational welding of these upper and lower parts to this circular section to form a bottle for drink.   13 Method according to any one of the claims   1 to 11, characterized in that the container is a box whose upper part is circular, relatively flat, having a fastener for opening the box 16 - by tearing.   14 Container obtained by a method described in   any of claims 1 to 13.   By proxy of COSDEN TECHNOLOGY INC. The representative is R Baudin.