FR2717775A1 - Container for storing and / or transporting liquids. - Google Patents

Abstract

The invention relates to a container for the storage and / or transport of liquids comprising an internal structure (2) at least partially encapsulated in a synthetic material, characterized in that the internal structure (2) is made in one piece in a material. plastic.

Description

The invention relates to containers for storage and / or transport of

  liquids and in particular containers capable of withstanding pressure, such as

  beer, as well as a process for obtaining such containers.

  Many containers of this type are known in the state

of technique.

  Mention may in particular be made of document DE-35 33 406 which describes a container for beverages constituted by an internal metal structure coated in a coating of material

  synthetic, such as a polyurethane resin.

  Document DE-39 13 643 also describes a container of this type whose metallic internal structure has a symmetry of revolution, while the coating of polyurethane resin is of polygonal shape with thicker columns at the edges. This particular shape facilitates stacking and storage of containers and their

  provides appropriate resistance.

  However, these containers with an internal metallic structure

have drawbacks.

  Indeed, this metallic structure is conventionally

  consisting of two half-shells connected by a weld.

  However, these containers are repeatedly subjected to washing operations before being refilled. It is noted that the solder points cannot be washed completely during the washing operations and therefore constitute foci for the development of bacteria. In addition, the internal metallic structure has a relatively large surface.

  irregular which is therefore difficult to wash.

  Finally, the containers comprising an internal metallic structure have a relatively large weight, which is detrimental, both for their transport and for their handling. The object of the invention is to overcome these drawbacks by proposing a container for storing and / or transporting liquids comprising an internal structure at least partially coated in a synthetic material, characterized in that the internal structure is produced in a

  single piece of plastic.

  In one embodiment, said synthetic material

  coating is a polymerized polyurethane resin.

  Preferably, the polyurethane resin belongs to the

  family of ether-urethane polyurethanes.

  This type of product is particularly suitable for beer kegs. In fact, it provides better resistance to external agents and in particular to attacks from environments

bacteria like yeast.

  The internal structure is made of a food grade material, when the container is used for

drinks.

  In this case, the materials used are preferably

  inexpensive polyethylene and polypropylene.

  When the container is intended for carbonated carbonated drinks, the internal structure is preferably made at least partially of a substantially impermeable material

with carbon dioxide.

  Preferably, in this case, the material is chosen from the following families: polyamide, copolymer of ethylene and vinyl alcohol, polyvinylidene chloride, polyester terephthalate, polychlorovinyl or composite material of the type

  aluminum / modified polyethylene / polyethylene.

  To increase mechanical performance, the container has at least one insert and / or a reinforcement in said

synthetic coating material.

  The invention also relates to a method for obtaining a container for storing and / or transporting liquids, comprising the following steps: - placing in an mold, an internal structure made of a plastic material, - closing the mold so defining a closed cavity, injecting into said cavity a liquid resin, - ensuring the polymerization of said resin and

  - open the mold to remove the said container.

  In a preferred embodiment, said resin is a polyurethane resin, and belongs in particular to the

  family of polyurethanes of the ether-urethane type.

  Preferably, the method consists in placing in said cavity, before the resin injection, at least one insert and / or

a reinforcement.

  The invention will be better understood and other objects, advantages and characteristics thereof will appear more

  clearly on reading the description which follows, made on

  look at the accompanying drawings which represent non-limiting embodiments of the invention and in which: - Figure 1 shows, seen in section, a beer keg having the characteristics of the container according to the invention and - Figure 2 shows the process for obtaining a

container according to the invention.

  Referring to Figure 1, the container according to the invention takes the form of a beer keg 1. It has an internal structure 2 made of plastic material

  beforehand according to a conventional manufacturing technique.

  This internal structure is commonly called "liner".

  This internal structure 2 is, in this example, completely coated in a layer 3 of synthetic material, such as a polyurethane resin. The internal structure 2 can also be only partially coated in

synthetic material.

  Reference 4 designates an opening intended for the

  filling and cleaning the barrel 1.

  Referring to Figure 2, will now be described the

  process for obtaining according to the invention.

  A four-part mold 10 to 13 is used, for example. An internal structure (or liner) 2 previously produced in one piece, is placed on the lower part 10 of the mold. Centering means, such as the centering pin 16 can be provided. We then place the two parts

  side 11 and 12 of the mold and finally the upper part 13.

  The mold 10 to 13 and the internal structure 2 define, once the mold closed, a closed cavity 14 located between the

  internal walls of the mold and the external walls of the liner.

  Liquid resin is injected into the cavity 14 via the channel 15. The polymerization reaction which can be initiated by raising the temperature is controlled if necessary. When the reaction is complete, the mold is opened and a container is then obtained

as shown in Figure 1.

  In this example, the internal structure 2 is thus

  completely embedded in the resin.

  The withdrawal and / or adhesion which takes place during the polymerization ensures the cohesion of the assembly. Thus, the resin ensures the mechanical recovery of the forces required from the

  structure and the connection of the different elements together.

  This process makes it possible to add to the mold, all kinds of plastic or metallic inserts, these inserts being previously positioned in the cavity 14, formed between the mold and the internal structure. They are positioned by screwing or any other means of securing, or even by simple interlocking. Preferably, the inserts are not attached to the internal structure 2. In fact, the operation making it possible to attach an insert to the internal structure 2 is costly and the method according to the invention makes it possible to avoid it. FIG. 2 illustrates two types of inserts: a metal belt 17 which is positioned relative to the internal structure 2 thanks to a support 18 and a metal insert 19 which is extended by a reinforcement crown 20. The insert 19 is screwed around the opening 4 defined by the internal structure 2. A plug 21 is provided in the opening 4 and in a corresponding recess 22 in the upper part 13 of the mold. Its function is to center and keep the liner in position, by pressing it against the mold wall,

opening level 4.

  The resin injected will ensure after polymerization, the

cohesion of the whole.

  Mechanical performance can be increased, if necessary, by adjusting the thickness of the walls of the parts or by providing inserts and reinforcements of different shapes and types, simply placed in the mold, before

resin injection.

  The internal structure 2 is made of a waterproof material. The nature of this material is chosen solely according to the usage criteria related to the content and the cost of production. It is, for example, necessary that the material resist corrosion if the container is to receive corrosive chemicals or is of food grade

  when intended to come into contact with beverages.

  In addition, in the case where the tank is intended to contain carbonated carbonated drinks, such as beer, soda and other "soft drinks", the problem of permeability

  carbon dioxide becomes preponderant.

  In this case, a barrier material will be used, chosen from the following families: PA (polyamide), EVOH (copolymer of ethylene and vinyl alcohol), PVDC (polyvinylidene chloride), PET (polyester terephthalate), PVC (polychlorovinyl ) or aluminum / PE composite material

  (polyethylene) modified / polyethylene.

  Depending on the barrier effect to the diffusion of carbon dioxide which is sought, these materials will be used alone or in combination with others, in thicknesses varying from 10 mm to a few tenths of a mm. For this type of tank, the wall thickness of the liner is generally between 0.5 and 3mm. It is obtained by combining one or more of the aforementioned barrier materials, with a more economical food grade material, having good processing characteristics and compatible with the barrier material. This food-grade material is chosen from the families of polyolefins and modified polyolefins, such as free radical or linear low density polyethylenes, medium or high polyethylenes

density, or polypropylenes.

  For example, for an application of the beer keg type, a 2mm thick liner will be used, produced by multilayer blown extrusion, having the following structure: - low density polyethylene: 970 pm 6.6: 30 Mm polyamide - EVOH : 30 mm

  - low density polyethylene: 970 im.

  Such a structure makes it possible to reach a permeability value for carbon dioxide less than 5 cm3 / m2. 24h,

  which is sufficient for this type of application.

  The assembly constituted by the internal structure and possibly the inserts and / or the reinforcements being overmolded with a liquid resin, the external shape of the container can have any freedom of design. It can in particular include ergonomic handles such as the handle 24,

  centralizers for stacking drums, etc ...

  It is also possible to provide local coatings on the overmolded tank, such as the tread 25 or a foam coating to make the handles more

comfortable.

  In addition, the resin brings its intrinsic qualities.

  The choice of resins is made according to the characteristics necessary for the application (impact resistance, mechanical resistance, lightness, its "non-metallic", resistance to corrosion vis-à-vis the external environment). Preferably, the resins are of the reactive polyurethane type. In the case of beer kegs, this polyurethane is advantageously chosen from the family of polyurethanes of ether-uretane type such as that obtained by the reaction of a propylene polyoxide with diisocyanato-diphenylmethane (MDI). This type of product provides better resistance to external agents and in particular to attack by environments

bacteria like yeast.

  The container according to the invention can be used as a sealed container for the storage and transport of carbonated drinks, such as the beer keg, illustrated in the

figure 1.

  Compared to traditional manufacturing techniques in stamped and welded stainless steel, the process makes it possible to produce

  a light barrel, less noisy and impact resistant.

  The use of an internal one-piece plastic structure facilitates cleaning and drying during

drumming operations.

  The reference signs inserted after the technical characteristics mentioned in the

  claims are intended only to facilitate the

  understanding of them, and in no way limit their scope.

Claims (10)

  1. Container for storing and / or transporting liquids comprising an internal structure (2) at least partially coated in a synthetic material, characterized in that the internal structure (2) is produced in one piece in a plastic material.   2. Container according to claim 1 characterized in that said synthetic coating material is a resin polymerized polyurethane.   3. Container according to claim 2 characterized in that said polyurethane resin belongs to the family of   polyurethanes of the ether-urethane type.   4. Container according to one of claims 1 to 3   characterized in that the internal structure (2) is made of a food grade material and in particular, in polyethylene or polypropylene.   5. Container according to one of claims 1 to 4   characterized in that the internal structure (2) is made at least partially from a material substantially impermeable to carbon dioxide.   6. Container according to claim 5 characterized in that the material is chosen from the following families: polyamide, copolymer of ethylene and of vinyl alcohol, polyvinylidene chloride, polyester terephthalate, polychlorovinyl or composite material of the type   aluminum / modified polyethylene / polyethylene.   7. Container according to one of claims 1 to 6   characterized in that it comprises at least one insert (19) and / or a reinforcement (17, 20) in said synthetic coating material. 8. Method for obtaining a container for storing and / or transporting liquids, comprising the following steps: - placing in an mold (10 to 13), an internal structure (2) produced in one piece in a plastic material, - close the mold (10 to 13) so as to define a closed cavity (14), - inject into said cavity (14) a liquid resin, ensure the polymerization of said resin and - open the mold (10 to 13 ) to remove said container therefrom. 9. Method according to claim 8 characterized in that said resin is a polyurethane resin, and belongs   especially to the family of ether type polyurethanes- urethane.   10. Method according to one of claims 8 to 9   characterized in that it consists in placing in said cavity (14), before the resin injection, at least one insert (19) and / or a reinforcement (17, 20).