LAYERED COMPOSITE COMPRISING A FIRE-RETARDANT COMPOSITE MATERIAL

Abstract

A layered composite includes: a foam core made of a plastic foam; and a first cover layer and a second cover layer, between which the foam core is arranged, wherein at least one of the cover layers is a fiber material layer containing reinforcement fibers embedded in plastic. A plastic resin fills intermediate spaces between the cover layers in and around the foam core and holds the cover layers and the foam core together. The layered composite includes a fire protection layer made of a composite material on a side of the fiber material layer facing away from the foam core. The composite material contains hollow micro-bodies made of ceramics or glass in a plastic material.

Claims

1.-15. (canceled)

16. A layered composite, comprising: a foam core made of a plastic foam; a first cover layer and a second cover layer, between which the foam core is arranged, wherein at least one of the cover layers is a fiber material layer containing reinforcement fibers embedded in plastic; a plastic resin which fills intermediate spaces between the cover layers in and around the foam core and holds the cover layers and the foam core together; and a fire protection layer made of a composite material on a side of the fiber material layer facing away from the foam core, wherein the composite material contains hollow micro-bodies made of ceramics or glass in a plastic material.

17. The layered composite according to claim 16, wherein the composite material has a density of at most 0.8 g/ccm or at most 0.6 g/ccm.

18. The layered composite according to claim 16, wherein at least 80% by mass of the plastic material of the composite material consists of a polymer phase having a density of at most 1.5 g/ccm or at most 1.3 g/ccm.

19. The layered composite according to claim 16, wherein the hollow micro-bodies have a density of at most 0.4 g/ccm or at most 0.3 g/ccm.

20. The layered composite according to claim 16, wherein a proportion by mass of at least 80% of the hollow micro-bodies exhibits a greatest outer extent of at most 120 ?m and at least 20 ?m.

21. The layered composite according to claim 16, wherein the proportion by volume of the hollow micro-bodies of the composite material is larger than the proportion by volume of the plastic material of the composite material.

22. The layered composite according to claim 16, wherein the composite material has a lower density than the plastic resin which holds the foam core and the cover layers together.

23. The layered composite according to claim 16, wherein the plastic resin which holds the foam core and the fiber material layers together has a density of at most 1.5 g/ccm or at most 1.3 g/ccm.

24. The layered composite according to claim 16, wherein the fire protection layer has a thickness of at most 2 mm or at most 1.5 mm.

25. The layered composite according to claim 16, wherein at least 80% by mass of the plastic material of the composite material consists of a polymer phase which is or contains an epoxy resin or a vinyl ester resin or a saturated polyester resin or an unsaturated polyester resin or a bio-based polyphenol resin or an epoxy vitrimer or a mixture of two or more of these polymers.

26. The layered composite according to claim 16, wherein at least 80% by mass of the plastic material of the composite material consists of a polymer phase which contains or is a bio-based polymer material.

27. The layered composite according to claim 16, wherein a proportion by mass of at least 0.1% and at most 20% of the plastic material of the composite material, relative to the mass of the plastic material of the fire protection layer, contains fire protection additives.

28. The layered composite according to claim 16, wherein the composite material fills recesses on the outer surface of the foam core and/or intermediate spaces in the foam core, in order to reduce the resin absorption of the foam core and/or to protect the foam core from fire.

29. The layered composite according to claim 16, wherein the plastic material of the composite material is mixed with metal oxide particles in order to provide protection against electromagnetic interference pulses, wherein the metal oxide particles are at least 20 nm and at most 250 nm in size.

30. The layered composite according to claim 16, wherein the reinforcement fibers embedded in plastic are in the form of one or more plies of a textile sheet structure.

31. The layered composite according to claim 26, wherein the bio-based polymer material is a bio-based polyphenol resin and/or a bio-based epoxy vitrimer.

32. The layered composite according to claim 28, wherein the composite material fills open pores and/or perforations on the outer surface of the foam core.

33. The layered composite according to claim 16, wherein the plastic material of the composite material is mixed with metal oxide particles including zinc oxide particles, in order to provide protection against electromagnetic interference pulses, wherein the metal oxide particles are at least 20 nm and at most 250 nm in size.

34. A highly filled fire protection filler, which is a composite material containing hollow micro-bodies made of glass or ceramics in a plastic material.

35. A method for fire-retardant joining of lightweight structures, the method comprising: arranging a panel-shaped or shell-shaped first lightweight structure and a panel-shaped or shell-shaped second lightweight structure next to each other to form a join therebetween or one on top of the other to form an overlapping join; and filling the join with a composite material which contains hollow micro-bodies made of glass or ceramics in a plastic material to close any gap in fire protection which might otherwise remain between the adjacent lightweight structures.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Example embodiments of the invention are described below on the basis of figures. Features disclosed by the example embodiments, each individually and in any combination of features, advantageously develop the subject matter of the claims and the embodiments described above as well as the aspects. There is shown:

[0075] FIG. 1 a layered composite in accordance with an aspect of the invention in an isometric view;

[0076] FIG. 2 the layered composite in a cross-section;

[0077] FIG. 3 a region of a fire protection layer of the layered composite in a schematic representation; and

[0078] FIG. 4 a region of a modified fire protection layer in a schematic representation.

DETAILED DESCRIPTION OF THE INVENTION

[0079] FIG. 1 shows a layered composite in accordance with an aspect of the invention in the form of a panel-shaped semi-finished product. The layered composite comprises a foam core 1 made of a plastic foam, for example foamed polyethylene terephthalate (PET). The foam core 1 is structured such that it is three-dimensionally deformable. The foam core 1 is a sheet structure having a structure which allows the foam core 1 to be deformed around axes located in the surface, such that the foam core 1 can for example be shaped into a tube or a shell which is curved around different axes, without any appreciable mechanical resistance. The foam core 1 is sub-divided into a multitude of material islands 2 which are arranged next to each other in the plan view and delineated from each other by material attenuations. Connecting bridges 3 remain in the region of the material attenuations, which can in particular be formed as breaches, wherein each of the material islands 2 is connected to all of the immediately adjacent material islands 2 by at least one and preferably only one connecting bridge 3 in each case.

[0080] The foam core 1 is arranged between a first cover layer 7 and a second cover layer 8 which cover the foam core 1 on a lower side and an upper side.

[0081] FIG. 2 shows the layered composite in a section which is orthogonal with respect to the cover layers 7 and 8. The section extends through the material islands 2 and the connecting bridges 3 of the foam core 1. The cavities which remain between the cover layers 7 and 8 in the region of the foam core 1 and delineate respectively adjacent material islands 2 from each other but are bridged by the connecting bridges 3 are filled with a plastic resin 5. The plastic resin 5 also covers at least regions of the lower side and the upper side of the foam core 1, where it forms a thin resin layer in the transition from the foam core 1 to the respective cover layer 7 or 8. The plastic resin 5 connects the cover layers 7 and 8 in a material bond, wherein it fills or permeates the foam core 1 in the region of the cavities or otherwise configured material attenuations (FIG. 1). The plastic resin 5 forms a resin matrix which encloses the material islands 2 laterally and preferably also on their lower side and upper side.

[0082] The foam core 1 forms a base sandwich structure with the cover layers 7 and 8 and the connecting plastic resin 5. The base sandwich structure 1, 5, 7, 8 can itself form the mechanical framework for a lightweight structure, for example a lightweight panel or a lightweight shell structure, and in this function can absorb the static and/or dynamic loads of the lightweight structure.

[0083] As shown in FIGS. 1 and 2, the layered composite exhibits a fire protection layer 10 on a side of the cover layer 8 facing away from the foam core 1. The fire protection layer 10 consists of a composite material. The composite material can be applied directly to the cover layer 8. Alternatively, it is also possible to firstly apply an expediently thin intermediate layer, for example a gelcoat layer, to the cover layer 8 and to apply the composite material to this intermediate layer. The composite material can for example be sputtered, sprayed or applied by means of a roller onto the cover layer 8 or an optional intermediate layer.

[0084] FIGS. 1 and 2 indicate how the layered composite can exhibit an intumescent layer 15 on the side of the fire protection layer 10 facing away from the foam core 1, further outwards as viewed from the foam core 1. The intumescent layer 15 can be provided in addition to or instead of the optional intermediate layer. It can in particular be a gelcoat layer. The intumescent layer 15 and/or the optional intermediate layer can for example serve to improve fire protection and/or as mechanical protection for the fire protection layer 10 and/or the base sandwich structure 1, 5, 7, 8 below it.

[0085] FIG. 3 shows a small region of the fire protection layer 10 in a significant enlargement. The fire protection layer 10 consists of the composite material which consists of a plastic material 11 as a support or matrix and hollow micro-bodies 12 made of glass or a ceramic material distributed in the plastic material 11. Although the hollow micro-bodies 12 can in principle exhibit any shape, for example an elongated oval shape, they are expediently hollow micro-spheres. Suitable hollow micro-spheres made of glass are for example available from 3M Corporation (Minnesota, USA).

[0086] At least 80% by mass or at least 90% by mass of the hollow micro-bodies 12 have an outer extent of at most 120 ?m. More preferably, at least 80% by mass or at least 90% by mass have an outer extent of at most 110 ?m or at most 100 ?m. It is advantageous for at least 80% by mass or at least 90% by mass of the hollow micro-bodies 12 to have an outer extent of at least 20 ?m. More preferably, at least 80% by mass of the hollow micro-bodies 12 have a greatest outer extent of at least 30 ?m. If the hollow micro-bodies 12 are hollow micro-spheres, as in the example embodiment, the outer extent is the outer diameter of the hollow micro-spheres. By selecting the hollow micro-bodies 12 from the size range mentioned, a composite material having a low density on the one hand and a sufficient compressive strength of the hollow micro-bodies 12 on the other is obtained.

[0087] The plastic material 11 is at least substantially a polymer phase, wherein the polymer phase can consist of a single polymer or a combination of multiple polymers, including copolymers and polymer blends. The plastic material 11 can contain additives, for example mere fillers and/or functional additives, in particular fire protection additives and/or for example additives for shock absorption or another mechanical property and/or for improving or achieving electromagnetic shielding properties. The polymer phase, i.e. the solely polymeric ingredients, constitute at least 80% by mass or at least 85% by mass or at least 90% by mass of the plastic material 11. The one or more different additives provide the optionally remaining proportion by mass.

[0088] FIG. 4 likewise shows a small region of a fire protection layer 10 made of a modified composite material. The modified composite material differs from the composite material described above in that its plastic material 11 contains metal oxide particles 13, for example zinc oxide particles. The metal oxide particles 13 have outer dimensions in the range of 20 nm to 250 nm and serve to achieve or improve an electromagnetic shielding effect. The statements made with respect to the composite material of FIG. 3 otherwise apply, such as for example the statements made with respect to the upper limit for the proportion by mass of additives.

[0089] An epoxy resin having a density of between 1.17 g/ccm and 1.25 g/ccm can for example be used as the plastic material 11 for the fire protection layer 10. This plastic material 11 is mixed with hollow micro-spheres 12 having diameters in the range of 20 ?m to 120 ?m. Preferably, at least 80% by mass of the hollow micro-spheres 12 have a diameter of at most 110 ?m or at most 100 ?m.

[0090] The viscosity of the plastic material 11 is set to be low enough that the hollow micro-spheres 12 are completely wetted on their outer surfaces and densely packed once mixed, and the intermediate spaces remaining between the hollow micro-spheres 12 are uniformly filled with the plastic material 11. By selecting the material (polymer phase with optional additive or additives) and/or the temperature, the viscosity is also set such that the composite material, i.e. the mixture of the plastic material 11 and the hollow micro-spheres 12, can be uniformly applied by sputtering, brushing, rollering or the like.

[0091] In advantageous embodiments, the hollow micro-bodies 12 have a density of less than 0.4 g/ccm or less than 0.3 g/ccm, preferably even less than 0.2 g/ccm. In the mixture and also in the finished layered composite, i.e. when the fire protection layer 10 is solid, the fire protection layer 10 contains a proportion by volume of at least 60% or at least 70% of the hollow micro-bodies 12, and the plastic material 11 constitutes the respectively residual proportion by volume.

[0092] If the plastic material 11 does not contain any additives, the composite material and therefore the finished fire protection layer 10 will have a density of 0.74 g/ccm (0.6.Math.0.4 g/ccm+0.4.Math.1.25 g/ccm) on the basis of the values mentioned for the combination which is least favorable for weight. If, by contrast, the composition is selected to exhibit the mixing ratio and lower densities which are more favorable for the lowest possible weight, the composite material or the fire protection layer 10 consisting of it has a density of 0.49 g/ccm (0.7.Math.0.2 g/ccm+0.3.Math.1.17 g/ccm). If, as is preferred, the proportion by volume of the hollow micro-bodies 12 is increased to over 70%, the density of the composite material then formed decreases even further.

[0093] If, by contrast, additives are added to the polymer phase of the plastic material 11, for example 15% by mass of a phosphoric fire protection additive which typically exhibits a density of at most 1.82 g/ccm, the composite material has a density of slightly more than 0.77 g/ccm (0.6.Math.0.4 g/ccm+0.4.Math.(0.85.Math.1.25+0.15.Math.1.82) g/ccm), i.e. still below 0.8 g/ccm.