WO2014117772A1

WO2014117772A1 - Interior lining for a tank or a container, and arrangement

Info

Publication number: WO2014117772A1
Application number: PCT/DE2014/100029
Authority: WO
Inventors: Jörn Von Bornstädt
Original assignee: Fenotec Gmbh Leckschutzsysteme
Priority date: 2013-02-04
Filing date: 2014-02-03
Publication date: 2014-08-07
Also published as: EP2950954A1

Abstract

The invention relates to an interior lining for a tank or a container, consisting of a multi-layered structure which, as a plastics sheeting or coated fabric, is formed with layers made of different thermoplastic materials, and to an arrangement with a tank or container and with an interior lining arranged therein.

Description

Inner lining for a tank or a container and arrangement

The invention relates to an inner lining for a tank or a container and an arrangement.

background

In particular in connection with leak-prone tanks or containers which serve to receive and store fuels or chemicals, there is a need for an inner lining which can also be retrofitted.

Summary

The object of the invention is to specify an inner lining for a tank or a container.

The object is achieved by an inner lining for a tank or a container, consisting of a multi-layer structure, which is formed as a plastic film or coated fabric with layers of different thermoplastic materials.

Furthermore, an arrangement with a tank or container and an inner lining arranged therein is provided.

In the case of the inner lining, which may also be referred to as an inner shell, the multi-layer structure may have one or more barrier layers which individually or together form a barrier against fluids (barrier layers).

The one or more barrier layers may be multi-layered. The plastic film in one embodiment may have the following layers in the order indicated:

an outer layer consisting of at least 80% by weight of high density polyethylene (HDPE) or another polyethylene (PE), an intermediate layer of polyamide (PA),

an intermediate layer of ethylene-vinyl alcohol copolymer (EVOH),

an intermediate layer of polyamide (PA) and

an outer layer consisting of at least 80% by weight of High Density Polyethylene (HDPE) or another polyethylene (PE).

An adhesion promoter can be introduced between one or more of the layers.

The multilayer structure may have on one or both sides an electrically conductive and dissipative cover layer.

Bonding areas between multilayer construction sections may be free of the one or more barrier layers and / or the electrically conductive cover layer. The electrically conductive and dissipative cover layer may contain an electrically conductive additive.

At least the electrically conductive and dissipative cover layer may contain carbon nanotubes as an electrically conductive additive.

The plastic film may be resistant to fuels, such that the plastic film lets through most about 2 g of fuel per m ² and day at room temperature and ambient pressure. In the arrangement, the tank or container may have a receiving volume of at least 5000 liters. Between an inner wall of the tank or container and the inner lining, an intermediate layer may be arranged.

It is proposed in one embodiment, an inner lining for liquid containers, such as cylindrical fuel tanks. The inner lining may consist of a foil or of coated fabric. The inner lining may be composed of seams of sections. For example, the film or coated fabric is based on a plastic base material and has one or more barrier layers incorporated therein the penetration of liquids or gases through the layer structure completely prevented or significantly restricts.

Description of exemplary embodiments

Embodiments will be explained below with reference to figures of a drawing. Hereby show:

1 is a schematic representation of a tank in section,

2 is a schematic representation of a multilayer structure with a plastic film or a fabric,

3 is a schematic representation of a multilayer structure with a barrier layer,

Fig. 4 is a schematic representation of a weld in section and

Fig. 5 is a schematic representation of an open-topped container.

Fig. 1 shows a schematic representation of a tank 15 in section. It is an inner lining 13 for the tank 15, for example made of steel or fiber-reinforced plastic, intended for storage mainly of water polluting liquids, in particular fuels such as gasoline, biodiesel or ethanol. For this purpose, the inner lining 13 is made of a film (plastic film) or a coated fabric. The film or coated fabric is cut into sections and bonded to form an inner lining according to the dimensions of the respective tank.

In the upper end of the substantially cylindrical tank 15 of conventional construction, a dome 17 is welded with a flange to which a cover 18 can be screwed. On the inner wall of the tank 15 is an intermediate layer 14 of a selectively electrically conductive and air-permeable material and on the inside of a flexible inner lining 13 at. In the upper part of the dome 17, the intermediate layer 14 can be replaced by a layer of sponge rubber or the like, so that a gap between Innenaus- clothing 13 and the wall of the tank 15 is sealed at the top. This layer also serves as a support for a clamping ring 16 by means of which the inner lining 13 is firmly clamped in the dome 17. By a vacuum between the inner lining 13 and the wall of the tank 15, the inner lining 13 is held on the tank wall. In addition, inner lining 13 and tank wall 15 can be monitored. Alternatively it can be provided to dispense with the intermediate layer, so that the inner lining 13 can optionally rest directly on the inside of the wall of the tank 15. The inner lining 13 for the tank 15 or any other tanks can be designed as a plastic film with a multi-layer structure, it being possible for the several layers to consist of different thermoplastic materials. Alternatively, a multi-layer structure may be formed from a multi-layer coated fabric in which several layers of different thermoplastic materials are also provided.

The inner liner 13 may be provided with one or more barrier layers which severely limit or completely prevent the passage of gases and / or liquids through the inner liner 13. The multi-layer construction makes it possible to use the properties of different materials. The inner lining 13 is thus configurable for a wider range of uses or for very specific media.

A simple construction is a three-day construction (see Fig. 3), in which a base material 19 is present outside and inside and in which between the base material layers a single or multi-layer barrier layer 8 is integrated, which is a barrier layer particularly against liquids and / or gases (fluids). The barrier layer prevents together with the other layers, that at room temperature and normal pressure is not more than 2 g per m ² and day diffuses through the film layers.

FIG. 2 shows a schematic representation of a multilayer construction with a plastic film or a fabric for the inner lining 13.

For example, a top, electrically conductive layer (11 and 12) may be particularly weldable and conductive. The next layer (16 and 10) can be particularly well welded and already substantially resistant to the liquids. Another part of a barrier layer (7 and 9) can then give the material special stability or else be particularly dense against certain liquids against which the other layers are not tight. Another part of the single-layer or multi-layer barrier layer 8 can be particularly dense, so that the penetration of liquids and gases through the inner lining 13 is prevented. The one or more barrier layers 8, which in turn are single-layered or multi-layered, are integrated into the multi-layer structure in such a way that it has a specific thickness over the entire width and length of the inner lining 13. In the case of several barrier layers, these may consist of different material layers. So an aluminum layer to be involved, which particularly supports the tightness against gases. This is very important especially for volatile fuels. But it can also be used as a barrier layer 8 another material. In the case of combustible liquids can be provided that the inner lining 13 is electrically dissipative. It may be the top layer 1 (outer or outer layer) is provided with an electrically conductive additive or additive. This can be achieved for example by means of a coating or an additional layer which has been made conductive by means of additives or by the incorporation of carbon nanotubes at least into the uppermost layer of the film.

It can be electrically dissipative in the entire tank 15 or in parts of the tank 15, the side of the inner lining 13 facing the medium received in the tank 15. In order to achieve this, it is provided in one embodiment to provide a media-resistant PE (polyethylene) with carbon nanotubes and / or another comparable additive. It is also possible to mix another media-resistant plastic or rubber with carbon nanotubes and / or a comparable additive. This material is used for the inner layer in the construction of the inner liner 13. It fulfills the properties that the inner layer, which is especially exposed to the medium, has to fulfill. Thus, despite the addition of carbon nanotubes or another comparable additive, this layer is nevertheless resistant to media. The inner lining 13 can be easily connected, and also the joints do not allow any medium or vapors - beyond the extent required by the standard - through. On the other side of the inner lining 13, a PE with or without carbon nanotubes or a comparable substance is used. Between the two PE layers there is at least one barrier layer, for example EVOH. Instead of PE another plastic or rubber come into question, which is optionally media-resistant even without a barrier layer. By way of example, the layer structure in Fig. 2 may be as follows: FIDPE (High Density Polyethylene) (6), PA (Polyamide) (7), EVOH (Ethylene Vinyl Alcohol) (8), PA Polyamide (9), and FIDPE (High Density Polyethylene) (10). Bonding agents can be used between the layers.

On this layer structure, a film of HDPE (High Density Polyethylene) is applied with a proportion of carbon nanotubes 11. The carbon nanotubes are compounded into the film base material and then processed together into a film. This surface forms the inside of the tank 15 and is sufficiently electrically conductive by the addition of carbon nanotubes. This layer may have an electrical conductivity of at least 10 ⁹ Ω. The HDPE is largely resistant to the media such as gasoline. By the addition of carbon nanotubes, this resistance is not or hardly limited. The outer layers of the film can be welded well and are still sufficiently resistant to the media.

HDPE is resistant to almost all polar substances or solvents and can be welded relatively well. Polyamide is resistant to almost all organic substances or solvents. EVOH is resistant to the penetration of oxygen and carbon dioxide. To prevent permeation. Carbon Nanotubes do not affect the durability of HDPE as an additive or only very little and have a high electrical conductivity. This can already be achieved with the addition of carbon nanotubes with a maximum proportion by weight of 5%. This film is therefore also made from two films, as one can thereby use a base film, which is already available on the market and thereby reduce the cost of producing the film and rely on a product which is closer to series products that are produced anyway , In addition, contamination of existing facilities by the carbon nanotubes or a similar addition is avoided.

Particularly in the case of the inner lining 13 with an electrically conductive outer layer, only the inner side of the inner lining 13 can be coated or provided with a dissipative layer layer 6. Fig. 4 shows a schematic representation of a weld on the inner lining 13 in section. It is welded so that outer sides 2 of the inner lining 13, which are formed without the dissipative layer or coating, are welded together. Since this is a shear seam 4, which is not as strong, a film strip 3 is again welded to the outer sides 2, which reinforces the seam and increases the tensile strength of the seam. In addition, a reinforcing seam on the back inner lining 13 may be welded.

The inner lining 13 can be assembled for different container shapes. These can be round, circular or angular.

According to FIG. 5, the inner lining 13 can also be introduced as a tank space lining 20 in an open-topped container 22. Again, the barrier layer properties are beneficial.

The inner lining 13 is replaced by the multi-layer structure such a wide range of applications that the inner lining can be used for all common types of fuel. For example, the interior lining may be approved by DIBT (Deutsches Institut für Bautechnik) for biodiesel, ethanol, gasoline and diesel.

In the following, further aspects will be explained.

Due to many and constantly new developments of the mineral industry - which consists for example in adding fuels to a wide variety of additives - the demands on the plastic and the plastic film are changing. The addition of additives is always a risk with respect to the plastic film. The mineral oil companies do not reveal the additions of the additives and above all information about which additives were added. The proposed embodiments have the background to counteract this and to provide a plastic composite for a film for use in tank protection or secure storage of fuels and chemicals that can resist as much as possible all fuels and chemicals and the additives used therein. The object of such a plastic film is firstly to provide material impermeability to the medium and secondly to prevent permeation (gas permeability). It is in one embodiment, a film composite created that ensures the most common and most common fuels and chemicals (collectively referred to as media) safe resistance and impermeability of the plastic film. The plastic composite identified in tests consists of the plastics: HDPE (high density polyethylene), polyamide, EVOH (ethylene-vinyl alcohol) and a conductivity additive. These plastics are combined in such a way that they provide a high resistance to fuel and chemical media. These three plastics have the following properties that can cause resistance to both fuels and chemicals: HDPE is resistant to almost all polar substances or solvents; Polyamide is resistant to almost all organic substances or solvents; and EVOH is resistant to the permeation of oxygen and carbon dioxide. This prevention is also called permeation. Permeation is the reading that indicates how much of the gases (eg, oxygen and / or carbon dioxide) migrate through the wall of the material in a given time and are released into the environment.

The three materials HDPE (or polyethylene in general), polyamide and EVOH form a basic composite for the formation of the proposed plastic film. The proposed film structure for use in the storage of fuels and chemicals brings the three material groups HDPE, polyamide and EVOH together to form a film. Since these three materials in their molecular structure can not connect to each other, the joining is done by means of a so-called primer. Adhesion promoters are in particular substances which are used to improve the adhesion of composites. An adhesion promoter is thus an adhesive which offers good contact adhesion for both films to be bonded. In the present case, an adhesion promoter can consist of, for example, materials which activate their adhesive action at the melting temperatures of the plastics to be joined and firmly bond the plastics together. Such adhesives are also called "hotmels." An example of a film layer construction for a tank inner shell is, for example:

- outer layer of HDPE,

- adhesion promoter,

- intermediate layer of polyamide,

- adhesion promoter, Intermediate layer of EVOH,

- adhesion promoter,

- intermediate layer of polyamide,

- Adhesives and

- outer layer of HDPE.

The primer may also be omitted in one or more instances between the adjacent layers. Including that a layer of HDPE, polyamide or EVOH is present, it is to be understood here that the layer uses said material as a base material, wherein the layer may well also comprise further material component.

So far, it has not been possible to store most and most commonly used fuels (such as benzine, bio-diesel, ethanol, kerosene, etc., ie almost all fuels) in tanks lined with foil.

When storing fuels of any kind and also other media that experience electrical charges when being filled into a tank, an electrical discharge of a charge, which results from the movement of the medium during filling, but also by movements during storage, guaranteed be. Advantageously, therefore, on an outside of the film, which comes into contact with the medium, a dissipative material is introduced into the outer layer of the film or applied by application by the outside is coated. From an economic point of view, introducing a dissipative material directly into the film is the better solution. This means that the outer layer is provided with an electrically conductive additive or additive. Depending on the application, it is possible to produce the conductive layer of the film, which has as a base material polyethylene, directly in one operation in conjunction with the plastic composite structure with the layers polyamide - EVOH - polyamide or depending on production possibility also separately in the wake to apply the middle layers (middle layers).

Another fundamental problem is the combination of these basic materials from different basic materials into one product. The processing technique of combining the different materials into one product was another hurdle. When The starting point was selected from the materials polyethylene or polypropylene, polyamide and EVOH. They are structurally the materials that guarantee the best possible resistance to fuels of all kinds. Regardless of the provided (basic resistance is to be noted that the long-term resistance should be at least 10 years.

Returning to the necessary electrical Abieitfähigkeit the film is to be considered that it is possible depending on the purpose, the dissipative layer of the film (the outer layer of the polyethylene base material) directly in one operation in conjunction with the middle layers (also referred to as the core structure) polyamide - EVOH - to produce polyamide or, depending on the manufacturing option, to apply it separately to the middle layers afterwards. This is done in such a way that a separate, so-called carrier film, consisting of the same material as the cover layer of polyethylene, which is equipped by means of an additive dissipative, applied in a separate operation on the core layer (laminated) is. The materials mentioned can be produced and used as a film or as a sheet product. This is determined by the shape of the tank or container to be lined. To form a tank, individual plastic film parts which are present in rolls are welded together by means of hot wedge or hot air or ultrasonic welding or heat pulse welding or high-frequency welding. The plastic film is preferably made of materials which are resistant to the penetration of fuels and chemicals of any kind and to the inner lining of tanks for the storage of fuels and chemicals of all kinds. Further, the plastic film is advantageously made of materials that are bonded together to form a solid unit. The thermoplastic material may also contain materials which have the necessary barrier properties for the storage of fuels and chemicals. The materials preferably each form a solid film, also referred to as thick film.

In the case of an inner lining of a tank or container, several film parts are welded together (preferably thermally) so that they completely line the interior of the tank.

A first embodiment of a film layer structure of a plastic film consists of several film layers with an outer layer of HDPE, a layer of polyamide, a Layer of EVOH, a layer of polyamide and an outer layer again of HDPE. Between the outer layers and the adjacent polyamide layer, in each case an adhesion promoter for connecting the film layers to one another can be arranged. In a further embodiment, in addition to the aforementioned film layer structure, a layer of a FIDPE which is dissipative, for example, by adding an electrically conductive additive, is applied to the outer FIDPE layer in each case.

It is such a plastic film to the inner lining of a tank or a container created, with a multi-layer film layer structure, wherein the layers consist of different thermoplastic materials. The thermoplastic materials may be fuel and / or chemically resistant. The film layer structure may consist of layers of materials with polyethylene, polyamide and EVOH as the base material. As polyethylene HDPE can be used. At least one outer layer of the film layer structure may comprise HDPE as the base material. Intermediate layers of the film layer construction may comprise polyamide and / or EVOK as the base material. The film layer structure may include an outer layer of HDPE, an intermediate layer of polyamide, an intermediate layer of EVOH, an intermediate layer of polyamide, and an outer layer of HDPE, in this order. Between the layers, a bonding agent for assembling the layers can be arranged. A dissipative, electrically conductive material may be applied to an outside of the film layer structure or incorporated into an outer layer of the film layer structure. An outer layer can be applied in a separate operation to a core structure of the film layer structure.

It may be provided an inner lining of a tank for receiving a fuel or a chemical chemical, which has to be introduced into the tank plastic film of the aforementioned type.

The features disclosed in the above description, the claims and the drawing may be important both individually and in any combination for the realization of the various embodiments. LIST OF REFERENCE NUMBERS

1 - inside

2 - outside

3 - foil strips

4 - shear seam

5 - Foil inner liner

6 - film layer

7 - barrier layer

8 - barrier layer

9 - barrier layer

10 - film layer

1 1 - Electrically conductive layer

12 - Electrically conductive layer

13 - inner lining

14 - intermediate layer

15 - tank

16 - clamping ring

17 - Dom

18 - Domdeckel

19 - Basic material

20 - Container lining

21 - Suspension of the container lining

22 - container

23 - gap

Claims

claims

Inner lining for a tank or a container, consisting of a multi-layer structure, which is formed as a plastic film or coated fabric with layers of different thermoplastic materials.

Inner lining according to claim 1, characterized in that the multi-layered construction comprises one or more barrier layers forming a barrier against fluids.

Inner lining according to claim 2, characterized in that the one or more barrier layers are multi-layered.

Inner lining according to at least one of the preceding claims, characterized in that the plastic film comprises the following layers in the order indicated:

an outer layer consisting of at least 80% by weight of high density polyethylene (HDPE) or another polyethylene (PE),

an intermediate layer of polyamide (PA),

an intermediate layer of ethylene-vinyl alcohol copolymer (EVOH),

an intermediate layer of polyamide (PA) and

Inner lining according to at least one of the preceding claims, characterized in that between one or more of the layers, a bonding agent is introduced.

Inner lining according to at least one of the preceding claims, characterized in that the multi-layer construction on one or both sides has an electrically conductive cover layer.

7. Inner lining according to claim 6, characterized in that connecting regions between multilayer construction sections are free of the electrically conductive cover layer.

8. inner lining according to claim 6 or 7, characterized in that the electrically conductive cover layer contains an electrically conductive additive.

9. inner lining according to claim 8, characterized in that at least the electrically conductive cover layer contains as an electrically conductive additive carbon nanotubes.

10. Inner lining according to at least one of the preceding claims, wherein the plastic film is resistant to fuels, such that the plastic film at most about 2 g of fuel per m ² and day at room temperature and ambient pressure passes.

11. Arrangement with a tank or container and an inner lining arranged therein according to at least one of the preceding claims.

12. The arrangement according to claim 11, characterized in that the tank or container has a receiving volume of at least 5000 liters.

13. Arrangement according to claim 11 or 12, characterized in that an intermediate layer is arranged between an inner wall of the tank or container and the inner lining.