WO2017026891A1

WO2017026891A1 - Insulation wall panel, method of manufacturing such an insulation wall panel, and use of such an insulation wall panel as a container wall

Info

Publication number: WO2017026891A1
Application number: PCT/NL2016/050539
Authority: WO
Inventors: René GIESBERS
Original assignee: Cargoshell Holding B.V.
Priority date: 2015-08-07
Filing date: 2016-07-19
Publication date: 2017-02-16
Also published as: EP3331779B1; NL2015281B1; EP3331779A1

Abstract

The invention relates to an insulation wall panel (11) comprising a central layer with one or several insulation panels, each insulation panel having a panel surface on either side and a circumferential edge, wherein the central layer (16) is provided on either side with a core layer (14) of insulation plates having a plate surface on either side and a circumferential edge. Each core layer is provided with a skin (12) layer at its side facing away from the central layer, while a reinforcement layer (15) is provided between the central layer and each of the adjoining core layers, and a reinforcement rib (22) extends between the two reinforcement layers around the circumferential edge of the or each insulation panel. Around the circumferential edge of one or several insulation plates there extends a reinforcement rib between a reinforcement layer and the adjoining skin layer. The invention further relates to a method of manufacturing such an insulation wall panel and to the use thereof as a container wall.

Description

Title: Insulation wall panel, method of manufacturing such an insulation wall panel, and use of such an insulation wall panel as a container wall Description

The invention according to a first aspect thereof relates to an insulation wall panel comprising a central layer with one or several mutually adjoining insulation panels, each insulation panel having a panel surface on either side and a circumferential edge, wherein the central layer is provided at each of its mutually opposing sides with a core layer of insulation plates that has a circumferential edge. A "circumferential edge" in the present document is understood to be an edge that extends between the two surfaces located at the two mutually opposing sides of a panel or plate across the thickness of the respective panel or plate. The insulation panels and insulation plates may differ from one another, but alternatively they may be (substantially) identical. The reason for the distinguishing use of the two terms is merely one of clarification, so as to make a distinction between the central layer and the core layers. The term "insulation" in the present document denotes thermal insulation.

Such an insulation wall panel is known and is used, for example, in domestic freezer cabinets. Because of its high insulation value, the insulation panel used herein is a VIP (Vacuum Insulation Panel), i.e. a panel filled with insulating material and subsequently evacuated. The known insulation wall panel or VI P is coated with a synthetic resin foam, which does have an additional insulating effect, but is mainly designed for preventing damage to the VIP panel, or at least reducing the risk thereof. Indeed, if the wall of a VI P panel is pierced, the vacuum will be lifted and a major portion of the insulating effect will be lost forever. The known insulation panel's application possibilities are limited because of its vulnerability. Depending on the desired characteristics of an insulation wall panel, an alternative insulation panel other than a VI P may be used, for example one made of synthetic resin foam. In that case the insulation value may be comparatively low, but the consequences of damage are less serious than with a VI P panel.

The present invention aims to improve an insulation wall panel as described in the introduction such that it has wider application possibilities, especially as a construction panel. To this end, the present invention provides an insulation wall panel as described in the introduction, wherein each core layer is provided with a skin layer at its side facing away from the central layer, wherein a reinforcement layer is provided between the central layer and each of the adjoining core layers, wherein at least a reinforcement rib extends around the circumferential edge of the or each insulation panel between the two reinforcement layers, and wherein at least a reinforcement rib extends around the circumferential edge of one or more insulation plates between a reinforcement layer and the adjoining skin layer. The interconnection of the reinforcement layers and ribs gives the wall a structure such that it has a monolithic character. The two skin layers are protective layers that shield the core layers, which may be easily penetrable, against the introduction into these core layers of objects that come into contact with the insulation wall panel. The skin layer may comprise a plastic or a composite material. The skin layer could comprise a metal for the purpose of reinforcement, but such an insulation wall panel would provide a less satisfactory insulation than one with a plastic. The reinforcement layers and reinforcement ribs provide the insulation wall panel with a high bending stiffness.

The construction of the insulation wall panel according to the present invention as described above provides an improvement in the mechanical and thermal insulation characteristics as compared with those of the known insulation wall panel described further above. Not only the reinforcement layers and ribs, but also the skin layers positioned at a distance to one another contribute to the required bending stiffness of the panel. The degree to which they contribute thereto depends inter alia on the material from which these skin plates are manufactured. An increase in the stiffness of these skin plates directly increases also the bending stiffness of the panel. If the skin plates are constructed from fibre-reinforced plastic, the bending stiffness can be increased in a direction in which the greatest flexural stresses will occur by choosing a suitable fibre orientation. The fibre reinforcement can be optimally utilized in this manner.

In a preferred embodiment of the present invention, the central layer comprises one or several Vacuum Insulation Panels, denoted VI P panels hereinafter. VIP panels are known for their comparatively high insulation value when used as insulation panels. In addition, VIP panels have a comparatively high stiffness since they are panels having filled vacuum chambers. The VIP panels preferably have a rectangular circumferential edge. The panels can then be readily positioned next to one another, while substantially constant interspacings can be realized.

It is furthermore preferred that a core layer comprises insulation plates having a rectangular circumferential edge. Again, it is advantageous that the insulation plates can be provided next to one another with constant interspacings.

In a preferred embodiment of the present invention, reinforcement ribs are provided between the reinforcement layers in a staggered arrangement with respect to reinforcement ribs provided between a reinforcement layer and a skin layer. The mutual staggering of the relevant ribs provides a comparatively long cold bridge between the two skin layers as compared with reinforcement ribs that lie aligned with one another and bridge a comparatively short distance between the two skin layers.

It is preferred herein that a reinforcement rib between the reinforcement layers extends substantially in the centre of an insulation plate and/or that a reinforcement rib between a reinforcement layer and a skin layer extends substantially in the centre of an insulation panel. A maximum length of a cold bridge between the two skin layers is obtained in this manner at all times.

In a preferred embodiment of the present invention, a core layer comprises insulation plates made of a foam material. Foam material, for example plastic foam, is a comparatively inexpensive insulation material. If the central layer already gives the insulation wall panel a high insulation value, it may suffice to provide a comparatively inexpensive core layer of lower insulation value.

Alternatively, a core layer may comprise high-grade insulation plates, for example in the form of VIP insulation plates.

The core layer may alternatively comprise insulation plates of a solid material. This may contribute to a high stiffness of an insulation wall panel.

In a preferred embodiment of the present invention, a reinforcement layer is a fibre reinforced plastic layer. A fibre reinforced plastic layer can be generated in a simple manner in an insulation wall panel according to the present invention, as will be described further below in the present document. Given a correct choice of plastic and fibres, a core layer can be created in this manner which provides the insulation wall with a very high stiffness.

A very stiff core layer can be obtained after curing of synthetic resin when the fibre reinforced plastic layer comprises mats, fabrics and/or patterns of fibres. In addition, fibres in the form of mats, fabrics and/or patterns can be applied in a simple manner and to a defined thickness.

Preferably, the fibres of the fibre reinforced plastic layer comprise glass fibres, carbon fibres and/or aramid fibres. These types of fibres enhance the stiffness of the plastic layer.

In a preferred embodiment of the present invention, the reinforcement ribs comprise a plastic. The reinforcement ribs may be provided in the form of separate elements between the reinforcement layers, or they may alternatively be integral with the reinforcement layers, for example in that plastic is injected by a method to be discussed further below. If the reinforcement ribs comprise a fibre reinforced plastic, this will contribute to the stiffness of the insulation wall panel.

Connecting the reinforcement ribs integrally to one or both of the reinforcement layers prevents the ribs from shifting relative to the reinforcement layers, thus providing an additional stiffness against shearing.

If the reinforcement ribs comprise a reinforcement element made of a solid material, an excellent stiffness will be obtained between two mutually adjoining reinforcement layers.

According to a second aspect, the present invention relates to the use of an insulation wall panel according to the first aspect of the invention as a wall of a container, in particular a sea container.

Sea containers for cooled transport, also denoted reefers, have walls comprising sandwiched panels in which an insulating material, for example PUR foam, is accommodated between two skin layers. A specific problem that manifests itself in reefers is a delamination of the core layer. This is caused by the considerable forces to which the containers are exposed. The containers are arranged in high stacks on board a ship. During a sea voyage varying and strong forces are exerted on the containers, inter alia owing to the motion of the travelling vessel, which forces are greater in proportion as a container is lower down in a stacked column. This results in major shear forces in the walls, which may lead to an insulation layer becoming delaminated. The insulation value of an insulation wall is severely diminished by this delamination.

The problem of delamination is discussed in an article "Minimising Delamination" in "Maersk Container Industry, Integrated Reefer News, second quarter 2014". The solution described in the cited article is the use of a specific foam adhesion agent. The delamination problem, however, is only partly solved thereby.

The present invention according to its second aspect aims to provide a wall for use in a reefer container which has at least the insulation value of a known reefer container and which eliminates, or at least reduces to a large extent, the problem of delamination caused by said major shear forces. This object is achieved by the use of an insulation wall panel according to the first aspect of the invention as a wall for a reefer container. The monolithic properties of the insulation wall panel according to the present invention resulting from the structure thereof, in contrast to the Maersk container wall mentioned above, reduces the risk of delamination practically to zero.

Since most loading situations of an insulation wall panel involve both a flexural strain and shear stresses caused by transverse forces, a construction with core layers comprising insulating foam only, as in the known insulation wall panel, will suffer comparatively large additional deformations owing to the low shear resistance of the foam. The construction is furthermore very prone to delamination because of the low strength of the foam. The reinforcement ribs of an insulation wall according to the present invention provide a mechanically strong connection and thus generate a higher shear resistance between the skin plates. The reinforcement ribs provide an additional stiffness against shearing because they limit the relative shearing deformations of the layers interconnected by the respective reinforcement ribs.

If the reinforcement ribs are integrally joined to one or both of the reinforcement layers, it is prevented that the ribs can shift relative to the reinforcement layers, thus providing an additional stiffness that counteracts shearing.

A thermally well insulated container wall with a good resistance to shearing is thus provided thereby. A container constructed in this manner, especially if at least one layer, for example the central layer, comprises insulation panels or plates with a high insulation value, for example VIP panels or plates, will have a thermal insulation that is at least as good as that of the known reefer container wall.

According to a third aspect, the present invention relates to a thermally insulated sea container comprising an upper wall, a lower wall, a front wall, a rear wall, and two side walls. Such containers are known as so-termed reefers. A rear wall of a known reefer is provided with doors that give access to the container. A reefer may comprise its own cooling device at the front wall or it may be connected to an external cooling device. A cooling device may be accommodated in a frame that covers the entire front wall. The walls of known reefers are insulated by means of sandwiched constructions so as to minimize unnecessary energy consumption. This sandwiched construction in the known reefers consists of two thin metal outer skins and a core of thermally insulating foam in between.

The present invention according to its third aspect aims to provide a reefer that is better insulated against heat transfer than known reefers. This is achieved by the present invention in that at least the side walls comprise an insulation wall panel according to the first aspect of the present invention. Such a sea container or reefer is thermally very well insulated. The upper and/or lower wall of the reefer preferably also comprise such an insulation wall panel. A further preference is that the front and/or rear wall comprise such an insulation wall panel which may constitute a complete wall or which may be provided as a hinging door panel for providing access to the container.

To provide a sufficient strength and/or (shear) resistance to an insulation wall panel for it to be used as a container wall, it is preferred that a fibre reinforced reinforcement layer has a thickness lying in a range of between 0.5 and 3.0 mm.

To provide a sufficient strength and/or (shear) resistance to an insulation wall panel for it to be used as a container wall, it is preferred that a fibre reinforced reinforcement rib has a thickness lying in a range of between 0.5 and 3.0 mm.

To provide an insulation wall panel with a sufficient thermal insulation for it to be used as a container wall, it is preferred that a core layer comprises strips of plastic foam having a thickness lying in a range of between 10 and 30 mm.

To provide an insulation wall panel with a sufficient thermal insulation for it to be used as a container wall, it is preferred that a core layer comprises strips of VI P panels having a thickness lying in a range of between 10 and 25 mm. According to a fourth aspect, the present invention relates to a method of manufacturing an insulation wall panel according to the first aspect of the present invention, which method comprises the following steps:

a) providing a first mould part;

b) providing a material for a skin layer of the insulation wall panel;

c) providing insulation plates next to one another with interspacings on the material for the skin layer;

d) providing fibres in the spaces left open between the insulation plates and on the insulation plates;

e) providing insulation panels next to one another with interspacings on the fibres;

f) providing fibres in the spaces left open between the insulation panels and on the insulation panels;

g) providing insulation plates next to one another with interspacings on the fibres;

h) providing fibres in the spaces left open between the insulation plates;

i) providing a material for a skin layer on the insulation plates;

j) closing off the first mould part with a second mould part;

k) injecting a synthetic resin into the mould such that the synthetic resin permeates the fibre layers; and

I) curing the synthetic resin.

The method according to the present invention for manufacturing an insulation wall panel is based on a vacuum injection technology under foil, which is known to those skilled in the art. In this technology, dry reinforcement materials and dry core layers are placed in an airtight planar mould. The entire assembly is then covered with an airtight foil, an underpressure is generated under the foil, and synthetic resin is injected under the foil. After the reinforcement materials and the foam have been completely impregnated, the synthetic resin is cured and a fibre reinforced plastic panel has been created. The manufacture of an insulation wall panel with the staggered reinforcement ribs as described above is achieved in that the panels and plates of mutually adjoining layers are provided in a staggered arrangement relative to one another each time.

The method of manufacturing an insulation wall panel is a time- consuming method because an insulation wall panel cannot be taken from the mould until the synthetic resin has been completely cured. The curing time is several hours for an insulation wall panel that is to be used as a reefer wall panel.

In a preferred method according to the present invention, the provision of the fibres is steps d), f) and/or h) is effected in that in the respective preceding step an insulation plate or panel, as applicable, surrounded by a fibre mat is provided, whereby the number of steps is reduced and a reinforcement layer and/or reinforcement rib of a defined thickness can be realised in a simple manner.

It is preferred for the purpose of providing an insulation wall panel with a comparatively high thermal insulation value that a VI P panel is provided as the insulation wall panel or insulation plate.

A first step is to place the reinforcement layers of the first skin plate in the mould. Then the first core layer comprising PUR foam is realized in that strips of PU R foam are first enveloped all around in a fibre mat and then placed on top of a possibly first fibre layer for reinforcement of the first skin plate. This layer is then covered with a fibre layer which will form a reinforced layer later between the first core layer and a central layer that is to be subsequently provided. After that the VI P panels, which are again in the form of strips, preferably enveloped in fibres, and which are to form the central layer, are placed strip by strip on the stack realized thus far. The dimensions of the strips of said PUR foam layers and of the VI P panels are such that the lateral edges thereof, which constitute the partition walls owing to their envelopment in reinforcement layers, are in a staggered arrangement relative to one another. After the VI P panels have been provided, a fresh fibre layer is applied, whereupon the second core layer of PUR foam is provided, which may again be similarly constructed from layers of PUR foam enveloped all around in fibre layers. Finally, the assembly may be covered with a fibre layer that is to form the other skin layer of the insulation wall panel. The assembly of "dry" components in the mould is then ready for being injected with synthetic resin by the method of vacuum injection under foil referred to above.

It is indeed known to connect the skin plates directly to one another by means of a transverse beam, a so-termed "shear web". Such beams can transmit shear forces between the skin plates. However, such a connection leads to a cold bridge because the transverse beams as a result of their strength characteristics have a comparatively poor thermal insulation characteristic as compared with foam or VIP layers. Since the transmission of shear forces does not substantially decrease if it takes place by a roundabout way, it is opted for in a preferred embodiment of the present invention to subdivide the reinforcement ribs over the thickness of the panel and possibly to stagger them. When these portions of the reinforcement ribs are interconnected by reinforcement layers that are parallel to the skin layers, the shear loads can be transmitted. This "roundabout way" has little influence on the transmission of shear forces but it has a major influence on the cold bridge effect, i.e. it largely eliminates this effect. Furthermore, this construction with reinforcement ribs extending through the thickness of the panel is highly resistant to delamination.

The invention will be explained in more detail below with reference to a preferred embodiment of an insulation wall panel according to the invention. In the drawing:

Figure 1 is a diagrammatic front elevation of an insulation wall panel according to the present invention constructed as a container side wall;

Figure 2 is a diagrammatic cross-sectional view of a portion of an insulation wall panel according to the present invention;

Figure 3 diagrammatically shows in an exploded view steps for implementing a method according to the present invention;

Figure 4 is a perspective view of a reefer container according to the present invention.

Figure 1 is a diagrammatic front elevation of an insulation wall panel

1 according to the present invention constructed as a reefer container wall. The side wall 1 in this example has a length of 5700 mm and a height of 2400 mm. By way of clarification of the present invention, though actually not visible, full lines drawn in the container wall 1 indicate vacuum insulation panels (VIP panels) present inside the container wall 1 . In vertical direction there are two VIP panels 2 each time. It is prevented thereby that any damage to the container wall 1 , causing a leak in a VIP panel 2, will render a column leaky over the full height of the container wall 1 , whereby its insulation value would be considerably impaired. The VIP panels are each sandwiched between two PUR plates lying on either side of the relevant VI P panel 2. As is apparent from figure 1 , the VIP panels 2 and the PUR plates 3 are of equal width but they are arranged such that a plate always covers two panels over half the width thereof, and vice versa. The PUR plates 3 extend over the full height of the container wall 1 . This is because a local spot of damage in a PU R plate 3 has no impact on the insulation value in a different region of this PUR plate 3, in contrast to a VIP panel 2. It is not visible in figure 1 that the VI P panels 2 and the PUR plates 3 are mutually separated each time by a fibre reinforced plastic. This will be explained in more detail with reference to figure 2.

Figure 2 is a diagrammatic cross-sectional view of an insulation wall panel 1 1 according to the present invention. The insulation wall panel 1 1 is built up from a number of layers which will be described below in their order from top to bottom.

The layer of the insulation wall panel 1 1 shown as uppermost in figure 2 is a skin layer 12 manufactured from a cured gel coating. Below this there is a protective layer 13 of glass fibre reinforced plastic. The next layer is a core layer 14 manufactured from polyurethane (PUR) plates 25 lying next to one another and mutually separated by reinforcement ribs 21 manufactured from glass fibre reinforced plastic. Below the core layer 14 there is a next reinforcement layer 15, also manufactured from glass fibre reinforced plastic. Below this reinforcement layer 15 there is a central layer 16 composed of VIP panels 26 that are mutually separated by reinforcement ribs 22 of glass fibre reinforced plastic. A reinforcement layer 17 of glass fibre reinforced plastic lies below the central layer 16. Below the reinforcement layer 17 lies a next core layer 18 manufactured from polyurethane (PUR) plates 27 lying next to one another and mutually separated by reinforcement ribs 23. Below the core layer 18 we find a reinforcement layer 19 manufactured from glass fibre reinforced plastic. The bottom layer, finally, is a skin layer 20 which is again manufactured from a cured gel coating.

In contrast to the insulation wall panel 1 , the PUR plates 25, 27 on the one hand and the VI P panels 26 on the other are not stacked such that the plates 25, 27 and panels 26 overlap by their halves each time. Between the insulation layers 14, 16, 18 there is always a respective reinforcement layer 15, 17 present, and between adjoining PUR plates 25, 27 and VIP panels 26 there is always a respective reinforcement rib 21 , 23 and 22 of glass fibre reinforced plastic. These reinforcement layers 14, 16, 18 and ribs 21 , 22, 23, give the insulation wall panel an improved shear resistance. The reinforcement ribs 21 , 22, 23 together with the reinforcement layers 15, 17 form a cold bridge because the reinforcement ribs 21 , 22, 23 and layers 15, 17 are interconnected. Since the reinforcement ribs 21 , 22, 23 are provided mutually staggered over the insulation wall panel 1 1 , however, the cold bridge is lengthened by the sum of the horizontal distances between the relevant ribs 21 , 22, and 22, 23, respectively (actually the horizontal distance between the ribs 21 and 23). This lengthening of the cold bridge owing to the staggered positions of the reinforcement ribs 21 , 22, 23 results in comparatively little thermal leakage being caused by this cold bridge. The cold bridges are longest in a container wall 1 1 as shown in figure 1 , where the PUR plate 3 and the VIP panels 2 always overlap by half. The cold bridges are shortest in a situation in which the reinforcement ribs 21 ,

22, 23 are mutually aligned and in fact form a direct connection between the reinforcement layer 13 and the reinforcement layer 19. In figure 1 the VIP panels 2 are of the same width as the PUR plates 3. However, the VI P panels 2 and the PUR plates 3 may be of different widths.

Figure 3 diagrammatically shows the construction of an insulation wall panel according to the present invention suitable for serving as a wall of a reefer container, wherein the various layers are diagrammatically indicated with (thickness) ratios that need not necessarily correspond to the actual (thickness) ratios. To achieve this construction, a first mould part 31 is provided into which a 350 μηη thick gel coating layer 32 of an isolphthalic acid polyester is introduced. This layer is to form the outer side of the insulation wall panel and may be provided with a pigment. The gel coating 32 forms an uninterrupted whole and will form one of the outer walls of the insulation wall panel, comparable to a skin layer in figure 2, after the insulation wall panel has been manufactured. When the gel coating 32 has been partly cured, first a so-termed chopped strand mat 32a (CSM) of glass fibres with a weight of 225 g/m² is laid on and adhered to the gel coating 32. Then reinforcement layers for the skin layer are provided, i.e. a layer of 150 g/m² continuous filament mat (CFM) glass fibres 32b followed by two layers of 800 g/m² unidirectional (UD) glass fibre patterns 32c.

First core layer portions are deposited on this stack. These first core layer portions comprises PUR foam strips 34, corresponding to PUR plates in figure 2, with a thickness of 20 mm and a density of 35 kg/m³, enveloped all around in a layer of 150 g/m² of CFM 33. Although figure 3 shows the PUR foam strips 34 enveloped in glass fibre mats 33 as spaced apart for reasons of clarity, they will preferably be laid tightly against one another. Since the lateral sides of the PUR foam strips are also covered by the CFM mat 34, this will automatically lead to a plastic partition wall with glass fibre reinforcement of 2 x 150 = 300 g/m² after an injection with synthetic resin as described below. VIP panels 35 for the central layer are subsequently placed hereon, also enveloped all around in a layer of 150 g/m² of CFM 33. The VIP panels 35 are 15 mm thick and have a density of 200 kg/m³. Since the surfaces of the PUR foam strips 34 mentioned above and of the VIP panels 35 are both coated with the 150 g/m² CFM 33, the thin, reinforced plastic intermediate layer is automatically created thereby after an injection with synthetic resin. As was the case with the previous layer, the fibre reinforced synthetic resin partition walls are again created in that the edges of the VIP panels 35 are coated with 150 g/m² CFM 33 and the packed panels are laid tightly against one another.

Second core layer portions are provided on this package. These core layer portions are also formed by PUR foam strips 34 with a thickness of 20 mm and a density of 35 kg/m³, enveloped all around in a layer of 150 g/m² CFM 33.

The assembly is finally covered with two layers of unidirectional (U D) glass fibre patterns 32c of 800 g/m² each and also 1x CFM 32b of 150 g/m².

This entire stack is now covered with a so-termed peelply tear-off fabric 38, which is removed again after the insulation wall panel has been cured, and then with an airtight foil serving as a second mould part 36 and provided with an inlet opening diagrammatically shown as 39.

Although a number of layers in the figures are shown as one continuous whole, the layers may alternatively be provided in the form of smaller mats, patterns or sheets. The PUR foam strips 34 and the VIP panels 35 may be covered by a glass fibre mat also at their end faces, if so desired.

A filled mould closed on all sides is obtained in this manner. A synthetic resin is subsequently injected into the mould through the inlet opening 7. If necessary, a recess is provided in the adjoining skin layer 32 at the level of the inlet opening. The assembly is evacuated (to approximately 0.5 bar underpressure) and injected by a standard injection method with a standard orthophthalic acid polyester resin. After curing, the product is unmoulded, the foil and the peelply fabric are removed, and the edges are trimmed. The synthetic resin penetrates into the free spaces and in between the fibres of the glass fibre mats 32, 33. Once the mould has been completely filled, there is a waiting period until the synthetic resin has been cured into a plastic, whereupon the mould parts 31 , 36 can be separated. An insulation wall panel according to the present invention has thus been created, suitable for use as an insulating wall panel of a reefer and capable of absorbing the concomitant forces without the risk, or at least with a very small risk, of delamination through shearing.

It is alternatively possible to provide the layers and ribs of glass fibre as separate layers instead of enveloping insulation plates and/or panels in glass fibre mats. Figure 3 does not indicate any dimensions. A reason for this is that an insulation wall panel may be manufactured with many different dimensions. This ranges from a few decimeters to many meters, depending on the use of the insulation wall panel. It will be clear that an insulation wall panel of this kind should preferably not be cut to size, because this would cause leaks in VIP panels. The thickness of the insulation wall panels may also vary in dependence on the application. Furthermore, more or fewer layers may be provided in an insulation wall panel, as desired, preferably separated by fibre reinforced plastic. It is also possible for insulation wall panels and plates to have a different orientation relative to one another, depending on the insulation value. It is preferable, however, to cover at least one central layer of VIP panels with a PUR layer on both sides. The risk of a VI P panel being damaged is reduced thereby.

The description of the figures mentions specific materials for the various layers and ribs each time. The present invention is obviously not limited to these materials. Glass fibres may be replaced with alternative fibres such as carbon fibres, aramid fibres or the like. An insulation material other than PUR may be used for the insulation plates. Alternative, preferably comparatively strongly insulating insulation plates may be used instead of VI P panels. The reinforcement ribs and reinforcement layers are integrally connected to one another and made from the same material in figure 2, and so they are implicitly also in an insulation wall panel manufactured by a method according to figure 3. It is conceivable, however, to provide a layer of elongate rib elements in between the panels or plates, which elements are in contact with the synthetic resin after the latter has been injected. The reinforcement layers may also comprise solid plates.

Figure 4 shows a container 51 manufactured with insulation wall panels according to the present invention in perspective side view. A side wall 52 facing the viewer and the upper wall 53 are shown partly broken away such that the core layers 54 and the central layer 55 are visible. The doors 56, 57 and the other walls, which are not visible in figure 4, have also been manufactured with insulation wall panels according to the present invention. As is evident from the above, the present invention is not limited to the embodiments described in the present document. Many modifications, which may or may not be obvious to those skilled in the art, are conceivable within the scope of the present invention as defined in the ensuing claims. Although the invention was explained in particular with reference to the use of the insulation wall panel in a sea container, insulation wall panels according to the invention of considerably smaller or larger dimensions are equally conceivable. The dimensions of the various layers may obviously be adapted to fit the application.

Claims

1. An insulation wall panel comprising a central layer with one or several mutually adjoining insulation panels, each insulation panel having a panel surface on either side and a circumferential edge, wherein the central layer is provided at each of its mutually opposing sides with a core layer of insulation plates that have a plate surface at each of their sides and a circumferential edge, wherein each core layer is provided with a skin layer at its side facing away from the central layer, wherein a reinforcement layer is provided between the central layer and each of the adjoining core layers, wherein at least a reinforcement rib extends around the circumferential edge of the or each insulation panel between the two reinforcement layers, and wherein at least a reinforcement rib extends around the circumferential edge of one or more insulation plates between a reinforcement layer and the adjoining skin layer.

2. The insulation wall panel according to claim 1 , characterized in that the central layer comprises one or several VI P panels (Vacuum Insulation Panels), preferably having a rectangular circumferential edge.

3. The insulation wall panel according to claim 1 or 2, characterized in that a core layer comprises insulation plates having rectangular circumferential edges.

4. The insulation wall panel according to one or more of the preceding claims, characterized in that reinforcement ribs are provided between the reinforcement layers in a staggered arrangement with respect to reinforcement ribs provided between a reinforcement layer and a skin layer.

5. The insulation wall panel according to claim 4, characterized in that a reinforcement rib between the reinforcement layers extends substantially in the centre of an insulation plate, and in that a reinforcement rib between a reinforcement layer and a skin layer extends substantially in the centre of an insulation panel.

6. The insulation wall panel according to one or more of the preceding claims, characterized in that a core layer comprises insulation plates made of a foam material, preferably plastic foam.

7. The insulation wall panel according to one or more of the preceding claims 1 to 5, characterized in that a core layer comprises insulation plates made of a solid material.

8. The insulation wall panel according to one or more of the preceding claims, characterized in that a reinforcement layer is a fibre reinforced plastic layer.

9. The insulation wall panel according to claim 8, characterized in that the fibre reinforced plastic layer comprises mats, fabrics and/or patterns of fibres.

10. The insulation wall panel according to claim 8 or 9, characterized in that the fibres of the fibre reinforced plastic layer comprise glass fibres, carbon fibres and/or aramid fibres.

1 1 . The insulation wall panel according to one or more of the preceding claims, characterized in that the reinforcement ribs comprise a plastic.

12. The insulation wall panel according to claim 1 1 , characterized in that the reinforcement ribs comprise a fibre reinforced plastic.

13. The insulation wall panel according to one or more of the preceding claims, characterized in that the reinforcement ribs are integrally connected to one or both of the reinforcement layers.

14. The insulation wall panel according to one or more of the preceding claims, characterized in that the reinforcement ribs comprise a reinforcement element made of a solid material.

15. Use of an insulation wall panel as a wall of a container, in particular a sea container.

16. A sea container comprising an upper wall, a lower wall, a front wall, a rear wall, and two side walls, characterized in that at least the side walls comprise an insulation wall panel according to one or more of the claims 1 to 14.

17. The sea container according to claim 16, characterized in that at least the side walls are each manufactured as a single insulation wall panel according to one or more of the claims 1 to 14.

18. The sea container according to one or more of the preceding claims 16 to 17, characterized in that a fibre reinforced reinforcement layer has a thickness lying in a range of between 0.5 - 3.0 mm.

19. The sea container according to one or more of the preceding claims 16 to 18, characterized in that a fibre reinforced reinforcement rib has a thickness lying in a range of between 0.5 - 3.0 mm.

20. The sea container according to one or more of the preceding claims 16 to 19, characterized in that a core layer comprises strips of plastic foam having a thickness lying in a range of between 10 - 30 mm.

21 . The sea container according to one or more of the preceding claims 16 to 20, characterized in that a core layer comprises strips of VIP panels having a thickness lying in a range of between 10 - 25 mm.

22. A method of manufacturing an insulation wall panel according to one or more of the claims 1 to 14, comprising the following steps: