MULTIPLE WALL COMPRISING A MICROCELLULAR STRUCTURE

Abstract

The invention relates to a multi-layer wall, in particular thermally insulated hollow bodies or containers (30), the multi-layer wall (20) comprising at least an inner layer (21), a barrier layer (22) and an outer layer (23), the barrier layer (22) being adapted to form a barrier for oxygen and/or water vapour, the inner layer (21) and/or the outer layer (23) having a microcellular structure (24), the microcellular structure (24) having fluid bubbles (25), and the fluid bubbles (25) being product of a physically and/or chemically introduced blowing agent.

Claims

1. A multi-layer wall of a thermically insulated hollow body, the multi-layer wall (20) comprising at least an inner layer (21), a barrier layer (22) and an outer layer (23), the barrier layer (22) being adapted to form a barrier for oxygen and/or water vapour, the inner layer (21) and/or the outer layer (23) having a microcellular structure (24), the microcellular structure (24) having fluid bubbles (25), and the fluid bubbles (25) being product of a physically and/or chemically introduced blowing agent, wherein the thermal conductivity λ of the multi-layer wall (20) is less than 0.25 W/(m.Math.K), the thermal conductivity λ of the multi-layer wall being determined by generating a heat pulse on a lateral surface of the multi-layer wall (test specimen bottom side) and concurrently measuring the temperature rise by an IR detector on the opposite surface of the multi-layer wall (test specimen top side), the inner layer (21) having a layer thickness of 0.15 to 0.8 mm, and the total layer thickness of the multi-layer wall amounting to 0.5 to 1.2 mm.

2. The multi-layer wall according to claim 1, wherein the blowing agent in the microcellular structure (24) has inert gas.

3. The multi-layer wall according to claim 2, wherein the microcellular structure (24) has a cavity volume less than 60% to greater than or equal to 10%.

4. The multi-layer wall according to claim 1, wherein the diameter of the fluid bubbles (25) is less than or equal to 300 μm.

5. The multi-layer wall according to claim 1, wherein the barrier layer (22) comprises an ethylene vinyl alcohol copolymer (EVOH) or cyclic olefin copolymers (COC) optionally laminated with polychloro trifluoro ethylene (PCTFE).

6. The multi-layer wall according to claim 1, wherein the inner layer (21) and/or the outer layer (23) comprises thermoplastics, thermoplastic elastomers (TPE).

7. The multi-layer wall according to claim 1, wherein the inner layer (21) has a layer thickness of 0.15 to 0.8 mm, the outer layer (23) has a layer thickness of 0.15 to 0.8 mm and the barrier layer (22) has a layer thickness of 0.05 to 0.25 mm.

8. The multi-layer wall according to claim 1, wherein the multi-layer wall (20) comprises a first additional layer (26) between the inner layer (21) and the barrier layer (22) and/or a second additional layer (27) between the barrier layer (22) and the outer layer (23), the first additional layer (26) and/or the second additional layer (27) comprising coupling agents.

9. (canceled)

10. The multi-layer wall according to claim 1, wherein the multi-layer wall is product of an extrusion blow moulding.

11. The multi-layer wall according to claim 1, wherein the total layer thickness of the multi-layer wall (20) amounts to 0.5 to 1.2 mm.

12. A method for producing a multi-layer wall, wherein the method comprises the method steps of: 1) a) Providing each a granulate or a mixture of granulates to form an inner layer (21) and/or outer layer (23) of a multi-layer wall (20) having a microcellular structure (24); Forming an extrudate to form an inner layer (21) and/or outer layer (23) of a multi-layer wall (20) having a microcellular structure (24); Mixing at least one extrudate to form an inner layer (21) and/or outer layer (23) of a multi-layer wall (20) having a microcellular structure (24) with inert gas and/or carbon dioxide, and obtaining an extrudate comprising inert gas and/or carbon dioxide, and b) Providing a granulate of ethylene vinyl alcohol copolymer or cyclic olefin copolymers (COC), Forming an extrudate of ethylene vinyl alcohol copolymer or cyclic olefin copolymers (COC), and c) Coextrusion blow moulding of a hose having a multi-layer wall (20) having the layer design from the inside out: inner layer, barrier layer, outer layer, in a blowing tool or inserting the hose into a blowing tool, followed by the steps of d) optionally disconnecting or detaching the hose having a multi-layer wall, e) Blowing up the hose provided in the blowing tool having a multi-layer wall has (i) an outer layer (23) a) made of the extrudate comprising inert gas and/or carbon dioxide to form an outer layer (23) of a multi-layer wall (20) having a microcellular structure (24) or b) made of an extrudate, (ii) a barrier layer (22) made of the extrudate of ethylene vinyl alcohol copolymer or cyclic olefin copolymers (COC), and (iii) an inner layer (21) a) made of the extrudate comprising inert gas and/or carbon dioxide to form an outer layer (23) of a multi-layer wall (20) having a microcellular structure (24), or b) made of an extrudate, the multi-layer wall of the container comprising from the inside out an inner layer, barrier layer and an outer layer, at least one inner or outer layer or inner and outer layer has a microcellular structure (24), and f) Obtaining a multi-layer wall (20), or 2) a) (i) Extrusion blow moulding of an outer layer (23) of the multi-layer wall, a) from the extrudate to form an outer layer (23) of a multi-layer wall (20) having a microcellular structure (24), or b) from an extrudate to form an out layer (23) of a multi-layer wall (20), (ii.1) Providing an extrudate of ethylene vinyl alcohol copolymer or cyclic olefin copolymers (COC), (ii.2) Extrusion blow moulding of a barrier layer (22) from the extrudate of ethylene vinyl alcohol copolymer or cyclic olefin copolymers (COC), and (iii) Extrusion blow moulding of an inner layer (21) of the multi-layer wall, from a) the extrudate comprising inert gas and/or carbon dioxide to form an inner layer (21) of a multi-layer wall (20) having a microcellular structure (24), or b) from an extrudate to form an inner layer (21) of a multi-layer wall (20), and obtaining a multi-layer wall (20).

13. A method of using of a multi-layer wall (20) according to claim 1 or obtainable according to claim 12, as component of a container (30) for storing and optionally applying a liquid or pasty composition, a dental liquid or a dental gel, a dental adhesive, dental bonding, dentin coupling agent, dental primer or dental etching agent.

14. The method of using a multi-layer wall according to claim 13, wherein the container (30) comprises a bottle, a tube, single-dose vial, bag, sachet, box with cover and/or syringe body.

15. A method of using a multi-layer wall according to claim 1 or obtainable according to claim 12 as integral component of a container or hollow body for storing and/or transporting compositions, comprising paint, varnishes, adhesives, food and/or cosmetics.

16. The multi-layer wall according to claim 6, wherein the inner layer (21) and/or the outer layer (23) comprises polyolefins, thermoplastic olefins optionally as copolymer with polyamide, polyester, polystyrene or urethane, and/or polypropylene.

Description

DESCRIPTION OF THE FIGURES

[0112] FIG. 1 shows the multi-layer wall according to the invention in an enlargement, the inner layer having the microcellular structure.

[0113] FIG. 2 shows the multi-layer wall according to the invention in an enlargement, the outer layer having the microcellular structure.

[0114] FIG. 3 shows the multi-layer wall according to the invention in an enlargement, the inner layer and the outer layer having the microcellular structure.

[0115] FIG. 4 shows an enlargement of the microcellular structure.

EMBODIMENTS OF THE INVENTION

[0116] FIG. 1 shows the multi-layer wall 20 according to the invention of a bottle 30 in an enlargement, the inner layer 21 having the microcellular structure. The bottle 30 has a multi-layer wall 20 in at least one region, the multi-layer wall 20 comprising an inner layer 21, a barrier layer 22 and an outer layer 23. In FIG. 1, the inner layer has the microcellular structure 24, being characterised by fluid bubbles 25 encased. The fluid bubbles 25 have been occurred by a physically or chemically introduced blowing agent into a polymer and form a polymer foam. Blowing agent is an inert gas, in particular nitrogen, gaseous carbon dioxide and/or a mixture of at least two of said gases.

[0117] The inner layer 21 and/or the outer layer 23 comprises thermoplastics, in particular polyolefins, thermoplastic elastomers (TPE), in particular thermoplastic olefins optionally as copolymer with polyamide, polyester, polystyrene or urethane and/or polypropylene.

[0118] The barrier layer 22 comprises an ethylene vinyl alcohol copolymer or cyclic olefin copolymers (COC) optionally laminated with polychloro trifluoro ethylene (PCTFE). The barrier layer 22 is adapted to form a barrier for oxygen and/or water vapour. In an embodiment, the multi-layer wall 20 is product of a multi-layer coextrusion blow moulding with extrudates modified each for the respective layer.

[0119] FIG. 2 shows the multi-layer wall 20 according to the invention of a bottle 30 in an enlargement, the outer layer 23 having the microcellular structure.

[0120] The multi-layer wall 20 may comprise still additional layers in an embodiment. Thus, for example in one embodiment, at least one additional layer each may be arranged between the inner layer 21 and the barrier layer 22 and/or between the barrier layer 22 and the outer layer 23. Depending on the material of which the said additional layer is made of, additional properties may be given to the multi-layer wall 20.

[0121] FIG. 3 shows the multi-layer wall 20 according to the invention of a bottle 30 in an enlargement, the inner layer 21 and the outer layer 23 having the microcellular structure. Since the microcellular structure has a very low coefficient of thermal conductivity λ, the thermal conductivity of the multi-layer wall 20 of the bottle 30 is the lowest in this configuration of the layers compared to the previous configurations. The coefficient of thermal conductivity A is at approx. 0.025 to 0.2 W/(m.Math.K). Thus, overboiling of acetone-containing compositions in the bottle 30 during application is prevented, since hardly no heat is transferred from the user's hand to the acetone-containing composition in the bottle.

[0122] FIG. 4 shows an enlargement of the microcellular structure 24 with the fluid bubbles 25. The size of the fluid bubbles 25 depends on the amount of the blowing agent introduced and the material used.

[0123] In a preferred embodiment, a microcellular material according to the invention is produced having an average cell size of less than approximately 60 μm or 50 μm. In some embodiments, a particularly small cell size is desired and, in these embodiments, the material according to the invention has an average cell size of less than approximately 30 μm, particularly preferably less than approximately 20 μm, and in particular preferably less than approximately 10 μm, and most particularly preferably less than approximately 5 μm. The microcellular material preferably has a maximum cell size of approximately 100 μm or preferably less than approximately 75 μm. In embodiments where a particular small cell size is desired, the material may have a maximum cell size of approximately 50 μm, particularly preferably approximately 35 μm and most particularly preferably approximately 25 μm. A series of embodiments contain all combinations of these characterised average cell sizes and maximum cell sizes. For example, one embodiment in this series of embodiments contains a microcellular material, having an average cell size of less than approximately 30 μm with a maximum cell size of approximately 40 μm, and as another example an average cell size of less than approximately 30 μm with a maximum cell size of approximately 35 μm. This means that a microcellular material being adapted for a variety of purposes may preferably be generated for this purpose having a particular combination of average cell size and maximum cell size.

LIST OF REFERENCE NUMERALS

[0124] 20 multi-layer wall [0125] 21 inner layer [0126] 22 barrier layer [0127] 23 outer layer [0128] 24 microcellular structure [0129] 25 fluid bubbles [0130] 30 container, bottle