WO2012085212A2

WO2012085212A2 - Wall structure for thermally insulated containers having an extended temperature usage range

Info

Publication number: WO2012085212A2
Application number: PCT/EP2011/073806
Authority: WO
Inventors: Hubert Eric Walter
Original assignee: Hw Verwaltungs Gmbh
Priority date: 2010-12-22
Filing date: 2011-12-22
Publication date: 2012-06-28
Also published as: WO2012085212A9; DE102011015715A1; WO2012085212A3

Abstract

The invention relates to a wall structure for thermally insulated containers having an extended temperature usage range, in which objects, food, pharmaceuticals, biological samples, blood, blood plasma, or organs intended to be transplanted can be stored or transported under temperature control in a suitable form without an undesired impairment occurring over a long time period and without additional energy supply being required for additional cooling or heating. The wall structure comprises an inner wall made of a thermoplastic polymer that forms an inner container. At least one layer, which is made of a film made from a thermoplastic polymer, and/or a plate-shaped element made of a polymeric hard foam plastic layer, lies flatly against the inner wall. A multi-layer structure is connected thereto in the direction of an outer wall of the wall structure, said outer wall being made of metal and/or a polymer. The multi-layer structure comprises at least one film (4) of a thermoplastic polymer and a vacuum insulating panel or an insulating panel, which is made of a porous element or porous material.

Description

Wall construction for thermally insulated containers with extended temperature range

The invention relates to a wall structure for thermally insulated containers with extended temperature range in which objects, food, pharmaceuticals, biological samples, blood, blood plasma or organ intended for transplantation can be stored or transported tempered in any suitable form, without an undesirable impairment occurs over a longer period of time and no additional energy supply is required for additional cooling or heating. Containers which are equipped with a wall structure according to the invention can be used, for example, for mobile catering, as is to be carried out in particular in the aviation sector.

For transport and storage, temperature-sensitive Licher goods are previously used containers that achieve thermal insulation. In the simplest case, such containers are made of or with polymeric foams, such as polystyrene (polystyrene). Although these foams advantageously have a low

Net mass, the achievable thermal insulation is limited.

Furthermore, the use of vacuum insulation panels is known. These panels achieve improved thermal insulation compared to many other insulation materials and structures. However, this only applies as long as the high negative pressure required within the panels can be maintained. The outer shell of vacuum insulation panels is usually formed from at least one film, which may also be coated with a metal. However, both the film and in particular the connections (sealing seams) of the film for the gas-tight sealing of the panels are critical and it can come by mechanical stress or thermal influences to leaks, so that the vacuum conditions are lost inside. This reduces the achievable thermal insulation but considerably.

However, since the containers can be used within a wide temperature range, which can range from, for example, from -80.degree. C. to above 120.degree.

are not sufficiently solved.

In particular, polymers represent weak points. They can age faster or become brittle, which adversely affects their mechanical properties and in particular their gas-tightness. Conventional insulation containers are usually not designed for specific temperature ranges and therefore can not be matched to a specific cooling in a temperature range or it can be a certain temperature range above the respective

Ambient temperature should not be considered separately.

Since such containers are also filled with foodstuffs or other high standards of hygiene, they are also required to meet these requirements. Usually used containers are indeed cleaned more or less regularly. But it can also lead to neglect, so that uncleaned containers are used again. Another problem is the

Condensation, which can occur after cleaning. Used polymers can store by their chemical / physical properties, at least in the near-surface region of water. Thus, unwanted microorganisms in the form of viruses, bacteria, fungi or algae can cultivate in or on a container, which is of course undesirable and represents a high risk potential.

In addition, multi-layer wall structures are known in which different materials or wall structures are used. In order to achieve a high thermal insulation effect, but an increased thickness of a wall structure is required, resulting in a reduction of the usable volume. Usually, the net weight of containers formed in this way also increases, which is undesirable during transport and in particular in the aviation sector.

It is therefore an object of the invention possibilities for to provide improved long term thermal insulation to containers for transporting or storing temperature sensitive goods.

According to the invention this object is achieved with a wall structure having the features of claim 1. Advantageous embodiments and further developments of the invention can be realized with technical features designated in subordinate claims.

The wall structure according to the invention for thermally insulated containers is designed such that an inner wall of a thermoplastic polymer which forms an inner container is present. On the inner wall is directly to this at least one layer which consists of a film formed from a thermoplastic polymer, and / or a sheet formed from a polymer rigid foam layer present in a flat fit. However, this layer may also be applied selectively in an alternative according to the invention, which may be e.g. may be the case with existing stiffening elements there. Such stiffening elements may be elevations (punctiform or rib-shaped elevations). These elevations can be arranged or formed on a lateral end draft bevel. However, an adjacent arrangement is also possible according to the invention.

This is followed in the direction of an outer wall of the wall structure, which is formed of metal and / or a polymer, a multi-layer structure, which is formed from at least one sheet of a thermoplastic polymer and a vacuum insulation panel. In this multi-layer construction can be between outer wall and Vacuum insulation panel be arranged another hard foam plastic layer.

The outer wall may be formed of steel, aluminum, a thermoplastic polymer, or polymer coated steel or aluminum.

In the invention, it is particularly advantageous that vacuum insulation panels are protected by several layers against temperature changes. The layers achieve the so-called "onion peel effect", which can significantly hinder a change in temperature, which makes it possible to avoid heating or cooling in temperature ranges which are critical for the film sealing a vacuum insulation panel in a gastight manner embrittlement of critical low or higher temperatures and also lose their impermeability to gases, which in turn would lead to a deterioration of the insulating effect of vacuum insulation panels.Usually, the films for use in the temperature range between - 50 ° C and + 80 ° C can be used without When using the container but it is also required lower and higher temperatures, for example, during transport or storage of dry ice or hot drinks and food, a temperature of up to about 120 ° C. could have to comply.

With the wall construction according to the invention, the

Barrier effect of the multiple layers, which are arranged in front of or behind a vacuum insulation, can be exploited to protect the film from these very low or very high temperatures. As a result of these protective measures, at least the heat-insulating effect can be maintained over a significantly longer period of the service life and an increased field of use, which relates to the temperatures within a container, can be achieved. The maximum achievable temperature gradient of goods to be stored or transported in a container and a vacuum insulation panel sealing film can be increased with the invention.

Advantageously, a container containing a phase change within a predeterminable temperature range can additionally be arranged between the inner wall and a vacuum insulation panel. Thus, the effect described above for durable or significantly extended protection of the functionality of the vacuum insulation panels can be further improved. By suitable selection of the medium, a cooled storage of goods in the container or a longer keep warm, for example, heated food and drinks can be achieved. The container containing such a medium may be, for example, a plastic container having a cavity in which the medium is contained, which has the shape of a plate-shaped member. The medium can be permanently contained. However, refilling or exchange of medium via at least one closable filling opening may also be possible. By replacing the medium, adaptation to a desired temperature range at which the phase change occurs can be achieved. As a container, a film may be used, in which a phase change medium is included included. In this case, a carrier material, which with phase change immersed in the film, the support material can serve to stabilize the shape. Usually, the outer and inner walls of such containers are water and gas tight. To avoid condensation and water accumulation, which may occur, for example, during cleaning, it is advantageous to provide a semipermeable region in the inner wall and / or outer wall. Such a semi-permeable area should be for water vapor

and / or permeable to air in at least one area. Through the semipermeable region can be

Pressure equalization can be achieved. This is always favorable, for example, if there is a pressure that deviates from the internal pressure of the container and / or the ambient pressure due to a temperature change in the space between the inner and outer wall. For one or more semipermeable region (s), a material of microfibers, as may be mentioned i.a. commercially available from Gore. It can also be used a valve for pressure equalization. Also by this measure, the premature aging or destruction of the vacuum insulation panels enclosing and sealing foil can be avoided.

Preference may vacuum insulation panels with a honeycomb structure, in which the webs, the individual

Honeycomb separate, perpendicular to the inner wall and outer wall are aligned, are used. The honeycombs can in this case by means of two aligned parallel to the inner wall and outer wall plates or foils and with at least one gas-tight surrounding the entire vacuum insulation panel film. be closed. As the film (s) a variety of polymers also provided with metal coatings, which achieve an increased barrier effect can be used.

In this case, a plurality of thinner foils with each other and these then on a surface with a common sealing foil, which has a greater thickness than the other films together, be materially connected. The sealing layer decisively determines the temperature-dependent properties and a suitable polymer which is resistant to embrittlement and aging in the desired broad temperature range should be chosen for this purpose. This can e.g. Polyester (PET) or polyethylene variants, such as LLDPE. Preferably, these polymers should be metallized.

A usable in the invention vacuum insulation panel may also be formed with at least two honeycomb structures arranged parallel to each other. In the case of the honeycomb structures, the individual honeycombs should be arranged offset relative to one another so that the webs of the two honeycomb structures separating the individual honeycombs are arranged only partially overlapping. As a result, the heat conduction can also be reduced because of the reduced contact surface. Such an offset can also be achieved with honeycombs of different sizes in two honeycomb structures. In this case, the honeycombs of a honeycomb structure enclosed by the webs have an internal volume which deviates from the internal volume of the honeycombs of the respective other honeycomb structure.

The webs of the honeycomb structure may preferably be made of a paper material reinforced with synthetic resin. provides and be gas-tight. The individual honeycombs can be filled with a porous material. For this purpose, microporous aerogels, silicate-based, such as Kie seizäure but also fibrous materials or foams can be used. The honeycomb structure (s) can / can be applied to a support plate and connected with this ver. On the opposite side of a perforated cover sheet can be applied, which is sealed gas-tight after evacuation. This can be achieved with a gas-tight cover film.

At the respectively outwardly facing sides or between two honeycomb structures, a further separating layer made of a thermally insulating material may be arranged, preferably with low thermal conductivity. For this example, a pressure-stable micro-fleece can be used.

For protection against external mechanical influences and to further improve the gas tightness, an outside carrier material can be provided on vacuum insulation panels. For this purpose, a metal (steel, aluminum) or a suitable plastic ge be selected.

In particular, in vacuum insulation panels with honeycomb structure, it is possible to produce blanks from larger semi-finished products in each desired shape and size by simple cutting. It can also be introduced breakthroughs without significantly deteriorating the thermal insulation effect, since each honeycomb forms a separate evacuated cavity.

In areas of an outer corner of a container, which is formed with the wall structure according to the invention, the outer wall should be angled so far that at least a complete overlap of vacuum insulation panels is achieved. In corner areas then usually two vacuum insulation panels are arranged in abutment, so that there is a, albeit narrow gap results, which represents a thermal bridge. Their effect can be reduced.

When selecting suitable polymers which can be used in the wall construction according to the invention, care should be taken that at least the thermoplastic polymer forming the inner wall has antimicrobial properties. The polymer should also be suitable for the temperature range from - 80 ° C to at least 120 ° C and approved for use with food.

Polyphenylene sulfide may be preferred as the polymer

(PPS), polyetheretherketone (PEEK), polysulfone (PSU), polyphenylene sulfone (PPSU), polyethersulfones

(PES / PESU), polyetherimide (PEI), liquid crystal polymer (liquid crystal polymer LCP) or styrene polymers (syndioaktisches polystyrene - partially crystalline PS) are used. The polymers mentioned should be non-flammable and for contact with

(After KTW Plastics in drinking water) zugelas ^¬ sen food to FDA and EU regulations and with water. This also applies to hot water. Au ^¬ ßerdem they are resistant to hydrolysis. The use of these polymers can thus in the temperature range - 80 ° C to

120 ° C easily done.

In order to achieve or improve the desired antimicrobial action, inorganic additives based on silver or copper can be added to the polymer. In this case, for example, silver in the form of Nanoparticles are added directly in the injection molding or Extrudie ^¬ ren the polymer. The antimicrobial effect can also be achieved with ion-depositing compounds such as zeolites (aluminosilicates) or glasses.

In order to achieve an antibacterial effect with a reduction in the number of bacteria by 99.9%, the addition of about 1 to 2% by mass of such a suitable additive is sufficient.

For temperature-sensitive additives, encapsulation in a ceramic carrier can be carried out. This is advisable at the processing temperatures of the polymers. Polyphenylene sulfide (PPS) is processed at temperatures in the range 320 ^C C to 340 ° C, for example. For silver, as an additive in

Polyphenylene sulfide (PPS) is used, the interaction with the contained sulfur should be considered. Since it can be during the processing, such as injection molding, silver sulfide or copper sulfide ge forms ^¬, particles of an additive should be encapsulated and thereby the sulfide formation can be reduced at least at the high processing temperatures. However, a material or material used for the encapsulation / coating should allow for sufficient migration / diffusion of the additive to the outside.

The additives should be embedded directly in the polymer during processing. At the mentioned sufficient concentration in the polymer, effective ions are sufficiently available at the surface because of their migration / diffusion to the surface. As a result, a long effective time can be achieved over several years. An influence on the polyme- Regarding their mechanical properties, it can not be proven. The microbial effect is based on their damage to enzymes and cell walls. It leads to the killing of microorganisms on the surface.

The thermoplastic polymer forming the inner wall can be reinforced with glass fibers whose proportion is at most 50%, preferably at most 40%.

The invention will be explained in more detail with reference to examples.

Showing:

Figure 1 is a sectional view through an example of a wall structure according to the invention;

Figure 2 is a sectional view through another example of a wall structure according to the invention;

Figure 3 shows an example of a vacuum insulation panel with two honeycomb structures and

FIG. 4 shows another example of a vacuum insulation panel with two honeycomb structures.

Figures 1 and 2 show sectional views of a wall structure in a corner region of a container, which is formed with the wall structure.

In both examples, the inner wall 1 of glass fiber reinforced polyphenylene sulfide, in the silver particles are embedded with an average particle size of 5 μιη to 20 m and with a proportion of 1.2% by mass. The embedding of the particles can when extruding or even with plastic injection molding, which can be used for the production of the inner wall of the container forming the inner wall, take place.

In the examples shown in Figs. 1 and 2, a rigid foam layer 5, e.g. made of PET. The hard foam plastic should not be flammable, thermoplastic and closed-pored. Between

Inner wall 1 and rigid foam layer 5 is a film 4 made of a thermoplastic polymer, which is stable in the temperature range already mentioned, arranged or materially connected to the inner wall 1 and / or the rigid foam layer 5. Also, in the direction of the outer wall 2 facing surface of the rigid foam layer 5 is provided with at least one such film 4. Pointing outwards, the example shown in FIG. 1 is followed by vacuum insulation panels 3, which form a joint between the two vacuum insulation panels 3 in the corner area shown. The pointing in the direction of the outer wall 2 surfaces of

Vacuum insulation panels 3 are again provided with at least one film 4 and rigid foam layer 5. The outer boundary then forms the outer wall 2. This is formed from plate-shaped elements made of aluminum, which are coated on the surface with a polymer formed. In the illustration, it is clear that at least one outer wall is angled in the illustrated corner region of the container and the angled part is so long that the joint between the two vacuum insulation panels 3 is covered. The connection of the individual elements, walls and layers can preferably be produced by an adhesive and / or welded connection.

The example according to FIG. 2 differs from the example according to FIG. 1 in that a container 6 containing a phase change within a predeterminable temperature range is arranged between inner wall 1 and vacuum insulation panel 3. This container 6 is arranged between the two films 4, which are once applied to the rigid foam layer 5 and once on the Vakuumisolationspaneel. The container 6 may for example be formed of PET and, for example, with a salt solution in which the phase change in the range - 15 ° C occurs for cooling.

Figures 3 and 4 show two examples of de. Invention applicable vacuum insulation panels 3 in two views. The honeycomb structures are arranged one above the other and the webs 7.1 the di <separate honeycomb 7 separate from each other gas-tight are offset from each other, so that the contact surfaces of the webs 7.1 of the two Wabenstruktu Ren are reduced. In the structure, as shown in Figure 3, the honeycomb structures are arranged according ver sets and this results in a regelmä lar displacement of the webs 7.1.

In the example shown in FIG. 4, the honeycombs 7 of the upper honeycomb structure have a smaller size and the volume enclosed by the webs 7. 1 of the individual honeycomb 7 is thereby smaller than in the honeycomb 7 of the lower honeycomb structure. This also allows an offset of the webs 7.1 with reduced Kon- be achieved contact surface.

In the examples shown in Figures 3 and 4, the honeycomb structures on the top and bottom are closed by means of plates 7.2 gas-tight. The plates 7.2 can be glued or welded to the webs 7.1 on their outer faces.

On the. Representation of a film or a composite formed with several films, the / a so formed vacuum insulation panel 3 gas-tight against the environment, has been omitted.

Claims

claims

A wall structure for thermally insulated containers with extended temperature range, comprising an inner wall (1) made of a thermoplastic polymer, which forms an inner container to the direct

at least one layer consisting of a film (4) formed from a thermoplastic polymer, and / or

a plate-shaped element formed from a polymer hard foam plastic layer (5) is present in planar and / or punctiform manner or is arranged adjoining or adjacent thereto and

it is in the direction of an outer wall (2) of the wall structure, which is formed of metal and / or a polymer, a multilayer structure is arranged, which is formed from at least one film (4) of a thermoplastic polymer and a vacuum insulation panel (3). 2. Wall structure according to claim 1, characterized in that in the multi-layer structure between Vakuumisolationspaneel (3) and outer wall (2) a further rigid foam plastic layer (5) is arranged. 3. Wall structure according to claim 1 or 2, characterized in that the outer wall (2) made of steel, aluminum, a thermoplastic polymer or coated with a polymer steel or aluminum is formed. Wall structure according to one of the preceding claims, characterized in that between the inner wall (1) and a Vakuumisolationspaneel (3) a phase change within a predeterminable temperature range performing medium containing container (6) is arranged.

Wall structure according to one of the preceding claims, characterized in that in the inner wall (1) and / or outer wall (2) is formed a semipermeable region and / or there is a valve for pressure equalization.

Wall structure according to one of the preceding claims, characterized in that a vacuum insulation panel (3) with a honeycomb structure, in which the webs (7.1) which separate the individual honeycomb (7) from each other, aligned perpendicular to the inner wall (1) and outer wall (2) are, and the honeycomb (7) by means of two parallel to the inner wall (1) and outer wall (2) aligned plates (7.2) and at least one of the entire vacuum insulation panel (3) gas-tight enclosing film are closed.

Wall structure according to one of the preceding claims, characterized in that a Vakuumisolationspaneel ^' (3) is formed with at least two honeycomb structures arranged parallel to each other, in which the individual honeycomb (7) are arranged offset from one another, so that the individual honeycomb (7) from each other Webs (7.1) of the two honeycomb structures are arranged only partially overlapping.

8. Wall structure according to one of the preceding claims, characterized in that in areas an outer corner of a container, which is formed with the wall structure, the outer wall (2) is angled so far that at least a complete overlap of vacuum insulation panels (3) is reached.

9. Wall structure according to one of the preceding claims, characterized in that at least the inner wall (1) forming thermoplastic polymer has antimicrobial properties.

10. Wall structure according to one of the preceding claims, characterized in that the polymer with which the inner wall (1) is formed, is selected from polyphenylene sulfide (PPS),

Polyetheretherketone (PEEK), polysulfone (PSU), polyphenylene sulfone (PPSU), polyethersulfone (PES / PESU), polyetherimide (PEI), liquid crystal polymer (LCP) and styrene polymers (syndioactic polystyrene - partially crystalline PS).

11. Wall structure according to one of the preceding claims, characterized in that the inner wall (1) forming thermoplastic polymer with glass fibers, the proportion of which is not more than 50%, is reinforced.