EP4395985A1

EP4395985A1 - Composite material

Info

Publication number: EP4395985A1
Application number: EP22772852.4A
Authority: EP
Inventors: Rudolf Einsiedel; Matthias MIELKE
Original assignee: Cordenka Innovations GmbH
Current assignee: Cordenka Innovations GmbH
Priority date: 2021-08-31
Filing date: 2022-08-31
Publication date: 2024-07-10
Also published as: WO2023031260A1

Abstract

The invention relates to a multilayer material containing at least one layer made of a fiber-reinforced plastic and at least one layer made of a foam structure material, wherein the layer made of a fiber-reinforced plastic contains cellulose-based fibers in the form of filaments. The invention additionally relates to a hailstone-resistant roof structure for vehicles and buildings, a boat hull, headgear, and a protective panel, for example as an underbody protection element for a vehicle or as an impact protection element for aircraft.

Description

composite material

Description:

The invention relates to a composite material with a layer structure.

Composite materials are well known and used in various applications.

From the document DE 102015210653, for example, a cover laminate is known which is to be used for a vehicle seat. The cover laminate has a mixture of nanocrystalline cellulosic fibers and synthetic fibers. The document DE 102010000116, in turn, describes a foam element that is mixed with cellulose fibers. This is intended to improve the hydrophilic properties of the composite material

A disadvantage of the known composite materials, however, is that their production is generally not very environmentally friendly or their mechanical stability, for example their impact strength, is low.

It was therefore the object of the present invention to provide a composite with a layer structure which reduces the disadvantages of the prior art. The object is achieved by a multi-layer material that has at least one layer of fiber-reinforced plastic and at least one layer of a foam structure material, the layer of fiber-reinforced plastic containing cellulose-based fibers, such as in particular viscose or lyocell fibers in the form of filaments.

Filaments within the meaning of the present application are flexible, fibrous structures whose length is several orders of magnitude greater than their thickness, typically the length-to-thickness ratio is 100:1 or more. However, filaments can also have a length of several hundred meters or even several kilometers. For the purposes of the present application, it is irrelevant whether the filament is a single fiber, a strand of fibers guided in parallel, or fibers connected to one another by twisting, twirling, gluing or welding. Game spun from shorter fibers can also be filaments within the meaning of the present application. In addition, filaments within the meaning of the present application can also be comparatively short, uncrimped pieces that can be obtained by cutting a longer filament. “Comparatively short” is understood to mean pieces from 0.2 to 20 centimeters, preferably 2-15 cm in length.

The advantage of the multi-layer material according to this invention is that at least the layer made of fiber-reinforced plastic has a renewable raw material, which means that the product can be produced with a better CC balance than the prior art and the recyclability is also improved. The multi-layer material made from a combination of the at least one layer made of fiber-reinforced plastic and the at least one layer made of foam structure material also has particularly good impact resistance and impact strength without increasing the weight compared to conventional composites. A foam structure material is to be understood as meaning a material that has gas bubbles or gas bubbles, with one or more gas bubbles or gas bubbles being separated from one another by a solid wall material. Both foams are conceivable, which consist of a single block, as is the case, for example, with foam mattresses, or the foam can consist of individual, interconnected, small foam fragments, such as, for example, foamed beads welded together, as is the case, for example, with expanded polystyrene (e.g. Styrofoam ®) is the case. For example, foamed polymeric materials can form the foam structure material. However, honeycomb structures, such as honeycombs, should also fall under the invention as a foam structure material. The foam structure material preferably forms a foam structure layer whose two surfaces running essentially parallel to one another have a significantly larger surface area in the longitudinal extent than the side surfaces which run essentially perpendicular to the surfaces of the foam structure layer of the foam structure material.

The expression “a layer made of fiber-reinforced plastic” is also used below, it being clear that this means the at least one layer made of fiber-reinforced plastic.

In a preferred embodiment, the cellulosic fibers are cellulosic fibers such as rayon fibers. The particularly good impact strength of the multi-layer material is then due in particular to the ductile characteristics of the cellulosic fibers used in the fiber-reinforced plastic outer layer. The rayon fibers preferably used here have an elastic deformation behavior that makes it possible to absorb impact energy acting on the fiber-reinforced plastic without damaging it. The ductile character of rayon fibers can also be illustrated by the high elongation at break values of these fibers. achieve rayon fibers Elongation at break values of at least 5%, but usually 10-20%, while the elongation at break values of glass fibers are in the range of 2-4%. In the following, rayon fibers are understood to mean cellulose filament fibers that were obtained using the viscose process.

Due to its properties, the material is particularly interesting for use as an outer layer for roof structures such as vehicle roofs or canopies for buildings. Consequently, for example, a hail protection composite can be constructed from the multi-layer material, which is resource-saving and has improved mechanical properties compared to conventional hail protection composites.

In one embodiment, the multi-layer material can have a sandwich structure. In this embodiment, the at least one layer of foam structure material can be arranged as a core between two or more layers of fiber-reinforced plastic. In one embodiment, the multi-layer material consisting of at least one layer made of fiber-reinforced plastic and at least one layer made of foam structure material can also be used in combination with other materials. It is conceivable here that the multi-layer material is part of a laminate structure, with the multi-layer material preferably forming an outer layer of the laminate structure and being arranged in the laminate such that the at least one layer of fiber-reinforced plastic forms the visible surface of the laminate.

In one embodiment, the layer made of fiber-reinforced plastic has at least 30% by weight, preferably at least 40% by weight, more preferably at least 50% by weight, particularly preferably at least 60% by weight, of cellulose-based fibers in the form of filaments on the total weight of the fiber-reinforced plastic layer. Preferably the cellulose-based fibers are cellulose fibers which are present in the stated percentages by weight in the fiber-reinforced plastic layer.

In one embodiment, the cellulose-based fibers have been obtained from known manufacturing processes. Known production processes are, for example, a direct dissolving process or a regenerated process for the production of cellulose fibers. Among other things, processes are known as direct dissolving processes in which the production of cellulosic fibers from solutions in tertiary amine oxides, such as N-methylmorpholine-N-oxide (NMMO, Lyocell process, "Lyocell fibers"), ionic liquids (ionic liquids) and subsequent Precipitation takes place in suitable coagulation media. Other common processes for the production of cellulosic filaments are regenerated processes, in which cellulose is first chemically converted and dissolved into soluble derivatives such as xanthogenates (viscose process, "rayon fibers"), carbamates, or phosphates. The solution is pumped through spinnerets and finally regenerated into cellulosic filaments in the precipitation bath. The totality of fibers that is obtained by direct dissolving or regenerated methods is also referred to as "cellulose man-made fibers". In one embodiment, mixtures of cellulose-based fibers obtained by different regenerated and/or direct dissolving methods can also be used. Accordingly, for example, combinations of rayon fibers with lyocell fibers are just as possible as combinations of rayon fibers with fibers that have been obtained via phosphates or combinations of lyocell fibers with fibers that have been obtained via ionic liquids. Combinations of three or more different types of fibers are also possible.

Rayon fibers, for example, are preferably used as cellulose-based fibers. For example, rayon multifilament yarn can be used as the cellulose-based fiber material. Additionally or alternatively, lyocell fibers or a mixture can also be used as cellulose-based fibers cellulose-based fibers made from rayon fibers, lyocell fibers or other processes.

In one embodiment, the fiber-reinforced plastic layer contains the cellulose-based fibers in the form of yarns, cords and/or rovings. In the yarn, the fibers can, for example, be twisted relative to one another and/or present in multiple layers within the yarn. In the cord, several games can be present in multiple layers within a thread and have different twists and directions of twist, typically as a forward or open twist. Within a roving, the fibers are essentially parallel to one another. In another embodiment, the cellulose-based fibers can also be present as so-called ribbon yarns. In a ribbon yarn, the individual fibers lie side by side and, for example, against one another, are aligned in one direction and are essentially present in a single layer. The ribbon yarns can have a binder that fixes the fibers in their position.

In one embodiment, the fiber reinforced plastic layer comprises cellulosic fibers in the form of one or more unidirectional layers. A unidirectional sheet is a sheet in which the fibers within the sheet are aligned in one direction. For example, all fibers of a unidirectional layer can be aligned parallel to the main propagation direction of the fibers within the unidirectional layer. In the manufacture of the unidirectional plies, a unidirectional ply running in the direction of manufacture forms a so-called 0° ply. The fiber orientation of further unidirectional layers can have an angle deviating from the 0° layer, such as ±45°, ±60° and/or ±90°. In the unidirectional layer, the cellulose-based fibers can be in the form of rovings, yarns or cords. When using rovings, the fibers are preferably parallel to one another at a defined distance within the unidirectional layer. In another embodiment, the cellulosic fibers within the fiber reinforced plastic layer are in the form of a web. For example, a canvas fabric, atlas, satin, or twill fabric with basis weights, for example, between 100 and 1,000 g / m ² and thread counts, for example, between 2-20 threads / cm in the warp and 0.5-20 threads / cm in the weft, a fabric layer of form a layer of fiber-reinforced plastic. In one embodiment, the cellulosic fibers are present within the fabric layer in both the weft and warp directions. The layer made of fiber-reinforced plastic preferably has at least one, particularly preferably two and more preferably three or more fabric layers made of cellulose-based fibers. The use of double fabrics as cellulose-based fiber material for the layer of fiber-reinforced plastic is also conceivable (manufactured, for example, using a double warp beam).

In one embodiment, the cellulose-based fibers are present within a layer of fiber-reinforced plastic in the form of a knitted or knitted fabric. The knitted fabric can be, for example, a weft inlaid knitted fabric, a Raschel knitted fabric or a weft knitted fabric.

In one embodiment, the at least one layer made of fiber-reinforced plastic has a combination of different textile layers as the cellulose-based fiber material. For example, the fiber reinforced plastic layer may include one or more fabric layers and one or more unidirectional layers of cellulosic fibers. In one exemplary embodiment, the layer made of fiber-reinforced plastic has the yarns in one or more fiber layers in the form of unidirectional layers, woven fabrics, knitted fabrics, warp-knitted fabrics, nets and/or as a random fiber fleece. In one embodiment, the fiber-reinforced plastic layer is formed from a plurality of unidirectional layers, with the orientation of adjacent unidirectional layers differing by 45° in each case. In another embodiment, the location is off fiber-reinforced plastic constructed from a plurality of layers of fabric and / or from a number of layers of random fiber fleece. A combination of a unidirectional layer, a fabric layer and/or a non-woven fabric layer to build up the layer from fiber-reinforced plastic is also possible. It is also possible for a large number of fiber-reinforced plastic layers to be used, which have different textile layers as the fiber material. For example, a first fiber-reinforced plastic layer can have the cellulose-based filaments in the form of one or more fabrics. A second fiber-reinforced plastic layer can contain the cellulose-based filaments in the form of a non-woven material and/or a unidirectional layer. The first and the second fiber-reinforced plastic layer then form the at least one layer made of fiber-reinforced plastic.

Each layer of fiber-reinforced plastic can consequently have a plurality of fiber layers.

Preferably, the unidirectional layers, the woven fabrics, knitted fabrics, warp-knitted fabrics, nets and/or the random fiber fleece layer consist entirely (that is to say 100% by weight) of the cellulose-based fibers in the form of filaments. However, it is also possible for the layers mentioned above to consist only partially of the cellulose-based fibers in the form of filaments. For example, each layer can consist of at least 20% by weight, or 40% by weight or 60% by weight of cellulosic fibers in the form of filaments, based on the total weight of the fibers of the corresponding layer. The cellulose filaments in the above layers can preferably be combined with viscose staple fibers, other cellulosic fibers, including natural fibers such as cotton, flax, hemp, jute, sisal, ramie, etc. However, combinations with other polymeric synthetic fibers and with glass or carbon fibers are also conceivable. Unidirectional layers, wovens, knitted fabrics, warp-knitted fabrics, nets and/or random non-woven layers as here are also known to those skilled in the art as “semi-finished textile products”.

Of course, it is also possible that only individual layers consist entirely of cellulose-based fibers in the form of filaments and are combined with layers that are formed entirely or partially of fibers that are not cellulose-based.

In one embodiment, the layer made of fiber-reinforced plastic has a matrix made of duroplastic material, for example unsaturated polyester resins (UP), vinyl ester (VE), polyurethane (PU), or epoxy resins (EP) as the plastic. The layer made of fiber-reinforced plastic preferably has only a matrix of duroplastic material as the plastic, which in turn can be produced partly on the basis of renewable raw materials, such as the product "PTP" from Biocomposites and More GmbH, a polymer material based on triglycerides and polycarboxylic acid anhydrides.

In another embodiment, the layer made of fiber-reinforced plastic has a matrix made of a thermoplastic material, for example polyester, polyamide, or the like as the plastic.

In one embodiment, the plastic of the at least one layer made of fiber-reinforced plastic consists entirely of the previously mentioned matrix materials. Completely in this context means that the plastic consists of more than 80% by weight, preferably more than 90% by weight and particularly preferably 100% by weight of the matrix materials mentioned.

In a further embodiment, the layer made of fiber-reinforced plastic has both thermoplastic and duroplastic components as the plastic on. The two components can be mixed together to form a homogeneous material or they can be contained at different points in the layer of fiber-reinforced plastic. For example, embodiments are possible in which the fibers embedded in the fiber-reinforced plastic are provided with a thermoplastic coating and then embedded in a duroplastic material. The thermoplastic coating thus creates an additional interface between the fibers and the duroplastic material, which can absorb additional impact forces. The effect of the thermoplastic coating is to reduce the adhesion between the fibers and the duroplastic material and thus create an additional predetermined breaking point in the material.

In one embodiment, the multi-layer material may comprise more than one layer of fiber reinforced plastic, each layer of fiber reinforced plastic comprising a different plastic or the layers all comprising the same plastic.

In one embodiment, the matrix material that forms the plastic of the fiber-reinforced plastic layer is at least 10% by weight, preferably at least 20% by weight, more preferably at least 40% by weight and very particularly preferably at least 80% by weight. % obtained from renewable raw materials, based on the total weight of the plastic of the fiber-reinforced plastic layer. In the case of a multi-layer material constructed in this way, not only is the fiber material based (at least in part) on a renewable raw material, but the plastic is also based at least in part on renewable material. Advantageously, a fibre-reinforced plastic layer can thus be produced whose CCh balance compared to classic fibre-reinforced plastic materials that have been used to date (in particular glass-fibre reinforced, conventional, i.e. petroleum-based UP or EP), is significantly lower and can therefore be considered a particularly sustainable material.

In one embodiment, foamed polyester, foamed polystyrene, foamed polyvinyl chloride, foamed polypropylene, foamed polyethersulfone, foamed polyurethane, foamed epoxy resin and/or mixtures of the materials mentioned are used as the foam structure material.

In a further embodiment, cellulose foam or particle foam based on recyclate material is used as the foam structure material.

In a further embodiment, a honeycomb structure is used as the foam structure material. A honeycomb structure can be a so-called honeycomb structure, for example. The honeycomb structure can be made of a foam material - as described above - or of another material. In one embodiment, this is a cellulose-based material. The foamed polymers mentioned above, as well as water glass (potassium silicate), or other binders or adhesives, preferably those based on renewable raw materials, can be used as binders for forming corresponding foam structures in a honeycomb structure. In one embodiment, the honeycomb structure is formed from a cellulose-based material (for example cellulose), which was brought into the honeycomb structure, for example by means of a wetlaid process.

Preferably, the foam structure material consists of at least 10% by weight, preferably at least 20% by weight, more preferably at least 40% by weight and particularly preferably at least 80% by weight of renewable or made from recycled raw materials based on the total weight of the foam structure material. Again, the CO2 balance of the product is significantly improved if additional material from renewable raw materials is used. In addition, the recyclability of the multi-layer material can also be improved if more material from renewable raw materials is used. Cellulosic fibers, as an example of cellulose-based fiber material, have better recycling properties than glass fibers, for example. In mechanical recycling processes, cellulosic fibers typically experience less fiber necking than glass fibers, which increases the technical utility of cellulosic fiber recycle material over that of glass fiber recycle material. In the thermal recycling process, cellulose is used for a second time as an energy source in a CO2-neutral manner, while glass fibers form slag, which is disadvantageous in the operation of waste-to-energy plants.

Overall, the multi-layer material forms a product with sustainable characteristics, which can lead to an increased willingness to buy among environmentally conscious people, for example.

Both the cellulose-based filaments and the matrix material and the foam structure material can be provided with a flame-retardant finish. The cellulose-based filaments can also contain a flame-retardant finish. The flame retardant finish of the matrix, the cellulose-based filaments and the foam structure can be based on inorganic flame retardants such as vermiculite or aluminum hydroxide as well as on organic flame retardants such as organophosphorus compounds such as tris(chloroethyl) phosphate (TCEP), trischloropropyl phosphate (TCPP), trisdichloroisopropyl phosphate (TDCPP), triphenyl phosphate (TPP), tris-2-ethylhexyl phosphate (TEHP), tricresyl phosphate (TKP), isopropylated triphenyl phosphate (ITP), mono-, bis- and Trisisopropylphenyl) phosphates different

isopropylation grades, resorcinol bisdiphenyl phosphate (RDP), bisphenol A bisdiphenyl phosphate (BDP) or vinylphosphonic acid. Combinations of two or more of the compounds mentioned are also possible. The flame retardants can be embedded in the material of the fibers, the matrix or the foam structure material. The fibers can be coated with the flame retardant.

Another subject matter of the present invention relates to a roof construction for a caravan, a mobile home, a mobile home, a carport, a canopy or a building that has at least one multi-layer material as described above. Such a roof construction can consist partly or entirely of the multi-layer material described above.

Preferably, the multi-layer material can form the outer layer of the roof construction, for example in a laminate structure with other layers. The outer layer is the layer that faces the outside world, whereas the layer opposite the outer layer (inner layer) faces the object.

The fiber-reinforced plastic layer of the multi-layer material can be produced as an outer layer of the multi-layer material described in the vacuum infusion process. In this way, or through the use of similar shaping processes, it is possible to give the multi-layer material a high surface quality (class A), either by gelcoat treatment or by painting directly after shaping. A roof construction is thus provided in a simple manner which has a particularly high impact resistance, has a good CO2 balance and, moreover, also facilitates further processing, such as painting, for example. Another advantage is that such a roof construction is very light and thus increases the Weight - e.g. of mobile homes - compared to conventional glass fiber reinforced plastic roof constructions. The roof construction is thus also advantageously suitable for porches, in which the support elements of the roof construction are usually less solid (e.g. for design reasons) and have a lower load capacity.

A further object of the present invention relates to a boat hull made at least partially from the multi-layer material. In one embodiment of the boat hull, the boat hull has the multi-layer material as the inner layer, whereas the outer layer (which comes into contact with water if the boat floats in the water) has additional material. With the multi-layer material as the inner layer, the interior design of the boat wall can be designed to be visually appealing in a particularly simple manner (e.g. by appropriate painting) and the boat wall is nevertheless protected from damage from being kicked by the occupants due to its improved impact resistance.

In a boat hull, the multi-ply material of the present application may be part of a larger laminate structure having the multi-ply material of the present application either on the inside (non-water side), outside (water-facing side) or internally contains. The use of cellulosic fibers such as rayon or other cellulosic filaments in a composite waterside protected with EP resin, fiberglass, anti-osmosis agents, gelcoat and antifouling underwater on boats can result in obstacle impacts, grounding or underwater collisions, e.g. with containers lost by cargo ships, absorb significantly more energy than conventional composites. As a result, leaks will occur less often or be smaller and can therefore be controlled more easily with on-board resources (pumps, sealants). In the worst case, it increases the time which is necessary for the approach of helpers or for the crew to board the corresponding lifebuoys at sea. The gain in safety of a boat wall designed in this way is certainly significant in the underwater area. However, the use of a suitable matrix and reliable impregnation of the fibers are prerequisites for this application.

A further subject matter of the present invention relates to headgear for use in sports and/or in traffic, which has a multi-layer material with the features as described above. Such headgear is characterized by high impact resistance, which means that, for example, a good occupational safety class can be achieved for the headgear without the headgear becoming unfavorably heavy and thus uncomfortable. The headgear can consist entirely or at least partially of the multi-layer material. In the case of headgear that consists only partially of the multi-layer material, it is preferred if the multi-layer material is used as the outer layer. This outer layer can also be varnished particularly well, so that, for example, warning colors can be used as a varnish to increase the safety of the headgear. The headgear can be a protective helmet for cycling, motorcycling, skiing, snowboarding or rock climbing, or an equestrian cap.

Another object of the present invention relates to a panel for use as a protection for vehicles, comprising at least one multilayer material as described above. For example, an underbody protection element can have the multi-layer material and protect the vehicle against loose gravel, for example. A baffle is another application for the multi-ply material. The multi-layer material according to the present application can also be used as a lightweight material in aircraft construction, e.g or as a material for aerodynamic flaps such as Krüger, Fowler, landing or spoiler flaps or for rudders such as rudder, elevator or ailerons. The multi-layer material according to the present application can also be used for combinations of different types of flaps or rudders, which are known to those skilled in the art, for example, under the name “flaperons”. When using the multi-layer material in the aforementioned applications, the hail resistance of the correspondingly produced elements leads to improved operational safety, in particular because increased safety against the impact of hailstones, flying parts such as gravel or waste, birds or ballistic projectiles is guaranteed.

In addition, use as a baffle plate is also possible in aircraft construction, specifically as part of so-called “unpaved strip kits” or “gravel kits”, which are used for aircraft, which are thus equipped for landing on unpaved runways. In such a case, deflector plates incorporating the multi-layer material of the present application may be installed above the landing gear to keep debris or other debris from being thrown up from the fuselage or the engines and/or propellers. The multi-layer material according to the present application is particularly suitable for use in impact plates for aircraft, since it means a significant weight saving compared to the aluminum previously used for this purpose.

Furthermore, it is possible that the multi-layer material is used in combination with other materials. For example, such a composite material can be glass fiber or carbon fiber reinforced plastics have as a base layer and thus a reinforced structuring component, while on the outside the multi-layer material, as described in this application, is used to produce an impact-resistant surface. This applies both to cellulose fiber-reinforced plastic materials and corresponding components based on duroplastic and thermoplastic matrices.

Claims

Composite material patent claims:

1 . Multi-layer material containing at least one layer of fibre-reinforced plastic and at least one layer of foam structure material, characterized in that the layer of fibre-reinforced plastic contains cellulose fibers in the form of filaments which have been obtained by a regenerated process and/or by a direct dissolving process and in that the fibre-reinforced plastic contains a thermosetting matrix material.

2. Multi-layer material according to claim 1, wherein the layer of fiber-reinforced plastic contains at least 20% by weight of cellulosic fibers in the form of filaments, based on the total weight of the layer of fiber-reinforced plastic.

3. The laminated material of claim 1 or 2, wherein the cellulosic fibers are rayon fibers.

4. The multi-ply material of any preceding claim, wherein the fiber reinforced plastic sheet contains cellulosic fibers in the form of one or more unidirectional sheets.

5. The multi-layer material according to any one of the preceding claims, wherein the layer of fiber reinforced plastic comprises cellulosic fibers in the form of yarns contains.

6. The multi-layer material of claim 5, wherein the fiber reinforced plastic layer contains the yarns in the form of unidirectional layers, woven fabrics, or knitted fabrics.

7. The multi-layer material according to one or more of the preceding claims, wherein the layer of fiber-reinforced plastic contains epoxy resins.

8. The multilayer material according to claim 7, wherein at least 10% by weight of the matrix material was obtained from renewable raw materials, based on the total weight of the at least one layer made of fiber-reinforced plastic.

9. The multi-layer material according to one or more of the preceding claims, wherein the cellulosic fibers have a thermoplastic coating.

10. The multi-layer material according to one or more of the preceding claims, wherein the foam structure material comprises foamed polyester, foamed polystyrene, foamed polyvinyl chloride, foamed polypropylene, foamed polyethersulfone, foamed polyurethane, foamed epoxy resin or mixtures of said materials.

11 . The multi-layer material according to any one of the preceding claims, wherein at least 10% by weight of the foam structure material was obtained from renewable raw materials.

12. The multi-layer material according to claim 1, wherein the foam structure material comprises particle foam and/or honeycomb structure materials based on cellulose and/or recycled material.

13. A roof structure for a caravan, camper, a

Mobile home, a carport, a canopy or a building comprising at least one multi-layer material according to one of Claims 1 to 12.

14. A roof construction according to claim 13, wherein the multi-layer material forms an outer layer with the layer of fiber reinforced plastic.

15. Headgear for use in sports and road traffic, comprising at least one multi-layer material according to one of claims 1 to 12.

16. An impact plate, or an underbody protection element, or a boat wall, or an aircraft component comprising at least one multi-layer material according to one of claims 1 to 12.