EP2678490B1 - Lightweight construction element which is capable of bearing or is bearing - Google Patents

Description

The invention relates to a load-bearing or supporting lightweight component according to the preamble of claim 1.

From the DE 100 18 710 A1 is already designed as a wall element lightweight construction element of the type mentioned with a support structure is known, which consists of juxtaposed and / or stacked tubular hollow bodies and carries a coating to form the wall surfaces. The elongate tubular hollow bodies are made of paper, cardboard, plastics or the like. Recycled paper is particularly preferred as a low-cost starting material for producing the hollow bodies, since the rough surface in this case improves the adhesion of the coating, which is preferably in the form of a plaster layer. However, the plaster layer increases the weight of the lightweight elements, without it being improved by the carrying capacity of the support structure. In addition, untreated tubular hollow bodies of paper or paperboard have only a limited carrying capacity in their longitudinal direction, unless they have very thick boundary walls, which in turn increases the weight of the lightweight components. Another disadvantage of the known lightweight construction elements is that tubular hollow bodies made of paper can absorb water easily from the environment or from the plaster layer, as a result of which their load-bearing capacity is greatly reduced.

The DE 2836418 A already discloses lightweight components of the type mentioned, in which from impregnated with synthetic resin cylindrical paper tube form a multi-chamber hollow profile, wherein both the tubes and the gussets between the tubes for stiffening or improving the transmission of force can be filled with a cured foam.

The EP 1522648 A1 , the CH 323528 A , the WO 2007/123398 A2 and the DE 2117794 A disclose plate-shaped lightweight elements made of paper or cellulose, while the WO 2009/045095 A1 and the GB 2341619 A Reveal panels with a honeycomb structure.

Proceeding from this, the invention has the object to improve a sustainable or lightweight structural element of the type mentioned in that its carrying capacity is further improved.

This object is achieved by the combination of the features of claim 1.

As rigid foam, a hard foam is used, which has a large total pore volume and thus a low specific gravity, but in which the individual pores are very small and according to the invention have cross-sectional dimensions of less than 0.5 mm. The hard foam is a thermosetting reaction foam, namely a higher crosslinked rigid polyurethane foam, which is also referred to as PIR foam. When using such a rigid foam, two or more components of the starting material are introduced into a mold containing the tubular hollow body and crosslinked or cured in the mold.

It has been found by experiments that the load-bearing capacity of the multi-chamber hollow profile over that of the water-repellent coating and impregnation which increases the bending and / or compressive strength of the paper increases arranged, provided with a plaster layer tubular hollow body of untreated paper according to DE 100 18 710 A1 With corresponding cross-sectional dimensions and wall thicknesses can be increased many times, and thus the carrying capacity of the entire lightweight construction element. At the same time prevents the water-repellent coating after assembly of the lightweight element that moisture penetrates into the paper over the life of the lightweight element, which could affect the strength of the hollow section and thus the carrying capacity of the lightweight element.

A preferred embodiment of the invention provides that the hard foam is applied to at least one outside of the multi-chamber hollow profile facing away from the chambers. By using the rigid foam as a cover layer or alternatively as an intermediate layer between the outside of the hollow profile and an additional cover layer can be in comparison to the known lightweight element further reduce the weight and on the other hand increase the strength, since the foam despite a very low specific weight of a has higher strength than plaster or plaster. Also, by the mutual connection of the boundary walls of the chambers, the carrying capacity can be increased, since in this way buckling of individual boundary walls or wall sections is difficult.

In this case, the boundary walls of the adjacent chambers are expediently connected to one another by the water-repellent coating which is applied to the outer surfaces of the boundary walls and which glues the mutually adjacent boundary walls together. Where the rigid foam is applied to the outside of the multi-chamber hollow profile, the boundary walls of the adjacent chambers are appropriate connected by the rigid foam, which also acts as an adhesive or binder and holds the boundary walls together.

With the combination of features according to the invention can be plate-shaped lightweight elements with a basis weight of less than 2 kg / m ^{2 produced} at a thickness of about 50 mm, which are capable of a width of 1000 mm, parallel to the direction of the longitudinal center axes of the chambers loads of more than To carry 10 tons.

In order to prevent the penetration of moisture to the paper, the boundary walls of the chambers are provided both at its inner and outer periphery with the coating and / or impregnation so that neither from inside nor from the outside moisture penetrate to the paper and thereby the bending and / or pressure resistance of the boundary walls of the chambers and thus may affect the lightweight element. In addition, by a double-sided inner and outer coating and / or impregnation, a greater increase in the bending and / or compressive strength than in the case of a one-sided coating and / or impregnation and thus a further increase in the carrying capacity of the lightweight components can be achieved.

Preferably, the coating and / or impregnation consists of a resin which is applied to the inner and outer peripheral surfaces of the tubular hollow bodies either after or during the manufacture of the tubular hollow body of paper in the liquid state and then cured. It is expedient to use a resin which hardens rapidly with or without the application of heat, preferably a thermosetting reaction resin in the form of a two-component system which, in addition to the reaction resin, comprises an accelerator or catalyst for accelerating the Curing includes. A preferred embodiment of the invention provides for the use of a polyisocyanate or epoxyisocyanurate resin, for example a polyisocyanate or epoxyisocyanurate resin, available from Bayer MaterialScience under the name Blendur. Alternatively, however, other resins may also be used, such as epoxy resins or phenolic resins, which are also water repellent when cured and increase the flexural and / or compressive strength of the tubular hollow body of paper.

According to the invention, the hollow profile consists of one or more rows of tubular bodies arranged side by side, which abut with their outer periphery against the outer periphery of adjacent tubular hollow body and are glued to the adjacent hollow bodies, each hollow body defining one of the parallel chambers. In order to facilitate the introduction of foam in the interstices or gusset between adjacent hollow bodies, but the hollow section may alternatively consist of one or more rows of spaced apart tubular hollow bodies, so that the flowable foam from one side into a previously with the Hollow bodies fitted form can be introduced, where it penetrates through the gaps between the adjacent hollow bodies and thus fills the entire shape. This alternative is particularly suitable for wall elements containing only one or two rows of elongated, embedded in hard foam hollow bodies. In particular, such wall elements can be well used for the production of walls of freight containers, railway cars or other means of transport, where a low basis weight is particularly advantageous.

To facilitate the production of such tubular hollow bodies made of paper, these advantageously have cylindrical outer and inner peripheral surfaces or a circular cross-section, so that they can be produced on existing machines, as for example in the production of paper corrugated paper or paperboard rolls of paper towels or toilet paper rolls are used. These hubs are made by winding two or more strip-shaped layers of paper helically and overlapping each other onto a mandrel, with an adhesive applied to one or both strips of paper in the areas of overlap. Alternatively, however, the tubular hollow bodies may also be manufactured by winding wider sheets or webs of paper in the circumferential direction of the tubular hollow bodies in several layers one over the other. This invention alternative has a particularly high load capacity.

According to this alternative, when the tubular hollow bodies abut with their outer circumferential surfaces against the outer peripheral surfaces of adjacent tubular hollow bodies and are glued together by the coating and / or rigid foam, the lightweight supporting structural element can be further stiffened and, in the case of an insert as a plate-shaped wall element or as a columnar supporting element Its compressive strength in the vertical direction can be increased further, since the adjacent tubular hollow body support each other and hold each other in their position, which counteracts a buckling of individual tubular hollow body under load. By the mutual abutment of adjacent tubular hollow body and the volume of the chambers in the interior of the tubular hollow body in comparison to the total volume of the element Leichbauelements increased and thus the weight of the latter be further reduced without affecting the carrying capacity, since the latter is supplied to a large extent by the tubular hollow bodies.

The paper used is preferably paper of low quality, expediently a recycled paper which, without the coating and / or impregnation, only has to have a low bending and / or compressive strength, which, on the other hand, should preferably have a rough surface and a certain absorbency to ensure that a sufficient amount of the liquid applied coating and / or impregnation adheres to the surface of the paper and advantageously at least partially penetrates the paper.

Through experiments it has been found that even a relatively small wall thickness of the boundary walls of the chambers is sufficient to give the lightweight component a very high load capacity, so that the boundary walls according to a further advantageous embodiment of the invention from less than eight superimposed layers or layers, preferably from less than five layers or layers, and most preferably only two or three layers or layers of paper such that the wall thickness of the boundary walls is less than 4 mm, preferably less than 2 mm and most preferably less than 1 mm. With this wall thickness of the boundary walls, the chambers may conveniently have cross-sectional dimensions of about 50 mm so that the ratio between the wall thickness of the tubular hollow bodies and the cross-sectional dimensions is desirably less than 1:25, preferably less than 1:50 and most preferably about 1: 100 , With such dimensions load-bearing lightweight wall elements can be produced during construction single-storey houses with a roof do not require a supporting structure.

If the lightweight element is to be used as a plate-shaped wall element or as a columnar support element, the hollow profile is aligned so that the longitudinal axes of the parallel chambers have a vertical orientation. As a result, the boundary walls in the direction in which the weight of components arranged above it acts on the bearing wall or support element, have their greatest compressive strength, so that the wall or support element receives a maximum load capacity. The hollow profile extends advantageous throughout from an upper to a lower end of the lightweight component.

If the wall or support member is to be given a relatively small thickness, the hollow profile expediently encloses only a single row of juxtaposed chambers whose longitudinal central axes in the cross section expediently lie on a line.

In contrast, two or more rows of chambers can be arranged side by side for larger wall thicknesses, wherein the chambers of adjacent rows expediently offset from each other longitudinal central axes, in order to ensure the most dense packing of the chambers and a low basis weight. When the hollow profile consists of parallel cylindrical hollow bodies, the hard foam fills the gussets between the tubular hollow bodies, wherein it connects adjacent hollow bodies with each other and prevents mutual displacement or displacement of adjacent hollow bodies under load.

An additional stiffening of the lightweight element can be achieved by applying one or more layers of a fiber-reinforced resin, such as polyurethane with a fiber fabric or fiber fabric embedded therein, preferably directly onto the flat surface of the rigid foam, on one or both broad sides. Over the fiber-reinforced resin layer, a surface cover layer may be applied as a termination.

At the upper and lower ends of each wall or support member, end members are preferably attached which close the open upper and lower ends of the chambers. The end elements of lightweight wall elements are preferably elongate and extend along the top and bottom ends, provided on one side with projections which can be inserted into the open ends of the parallel chambers. The end elements ensure on the one hand that the upper and lower end of the chambers is closed and the wall or support elements at the upper and lower ends have no openings, and on the other hand improve the cohesion wall or support members, if they are tubular hollow bodies consist. The end elements are suitably connected by the rigid foam with the rest of the lightweight element, for example by being attached prior to curing of the rigid foam.

If the lightweight element is to be used as a plate-shaped floor or ceiling element, the parallel chambers also have vertical longitudinal central axes, in which case, however, a plurality of short tubular hollow bodies arranged in rows next to each other, so that they are perpendicular to the broad side surfaces of the floor or ceiling element are aligned and together one Form honeycomb structure. In this case, the upper and the lower ends of the Kammern. the honeycomb structure are closed by plates which abut against the aligned upper and lower end faces of the hollow profile.

Alternatively, the upper and lower ends of the chambers or honeycomb structure may also be closed by one or more layers of fiber reinforced resin or resin, for example by fiber reinforcement as a nonwoven, woven fabric or scrim of fibers on the respective upwardly turned or facing broadsides the honeycomb structure is laid so that the fleece, fabric or scrim completely covers the open ends of the chambers, and then impregnated with the resin and the resin is cured. The resin may preferably be a thermosetting synthetic resin which cross-links upon application of heat or UV radiation and thereby harden, or a two-component resin. Depending on the strength requirement, the fiber reinforcement can consist of glass, carbon, aramid or synthetic fibers. If required, one or more further layers of fiber-reinforced resin and optionally an additional surface covering layer may be applied as a finish. Alternatively, the honeycomb structure can also be placed with its broadside turned downwards on a resin impregnated layer of the nonwoven fabric, fabric or -gelege to close the ends of the chambers. In both cases, the ends of the boundary walls of the chambers connect with the curing of the resin with the latter, so that they are then firmly bonded to the layers of fiber reinforced resin and form a floor or ceiling element with high bending stiffness.

This type of lightweight element can be used with advantage as a floor or ceiling element for a cargo or living container, such as a sea or transport container, as the floors and ceilings of the latter are currently made of so-called multiplex panels from a tropical wood that will not be available for long.

If the lightweight structural elements are used in the construction of buildings or the like, they must have sufficient fire resistance, in Germany at least fire protection class B1S-D0 required, but fire protection class A is preferred. In order to increase the fire resistance of the lightweight components, a material with a relatively high temperature resistance is advantageously used for a coating or impregnation of the tubular hollow body, such as the aforementioned poly- or Epoxyisocyanuratharz, and on the other hand a temperature-resistant, dimensionally stable foam at higher temperatures, such as For example, the already mentioned PIR foam of fire protection class B1S-D0 or A1. This rigid foam has a specific weight of 40 kg / m ³ and is therefore very light, but on the other hand has such a hardness that it can be drilled or otherwise processed.

This makes it possible to form the hard foam on the opposite narrow sides of the adjacent lightweight components in their manufacture to a groove or spring, so that the adjacent lightweight components mate together and thus can be easily interconnected. In principle, it is also possible to mill the grooves and springs after the production of lightweight components on the narrow sides of the hard foam. Alternatively, the grooves and springs on the opposite narrow sides of adjacent lightweight components can also be formed by profiles made of metal or plastic, which are glued by the rigid foam with the hollow profile.

Fire protection class A1 can also be achieved in that the hard foam consists of microscopic hollow spheres of glass which are embedded in a non-combustible matrix, such as, for example, a waterglass adhesive.

Since a lightweight construction element with a hollow profile of cylindrical tubular hollow bodies arranged next to one another has an uneven surface structure unsuitable as a wall surface, a further advantageous embodiment of the invention provides that the rigid foam forms at least one and preferably two flat broad side surfaces, especially in the case of wall elements. However, the lightweight component may also be provided with one or two additional cover layers, which are formed by a voltage applied to a broad side against the hard foam and / or the hollow profile plate.

Preferably, in the latter case to increase the refractory plates of a mineral material used, preferably mineral plates of magnesium oxide and magnesium chloride with a glass fiber reinforcement, which are commercially available under the name Megapan and in a thickness of a few millimeters as a topcoat on the Lightweight element can be attached so that they form the visible outer surfaces. The plates are preferably connected by the rigid foam with the hollow profile or glued to this.

• Fig. 1 eine teilweise weg geschnittene perspektivische Ansicht von Teilen zweier Leichtbau-Wandelemente;
• Fig. 2 eine vergrößerte Querschnittansicht eines Teils von einem der Leichtbau-Wandelemente aus Fig. 1;
• Fig. 3 eine teilweise weg geschnittene perspektivische Ansicht von Teilen zweier modifizierter Leichtbau-Wandelemente;
• Fig. 4 eine vergrößerte Querschnittansicht eines Teils von einem der Leichtbau-Wandelemente aus Fig. 3;
• Fig. 5 eine teilweise weg geschnittene perspektivische Ansicht von Teilen von zwei weiteren modifizierten Leichtbau-Wandelementen;
• Fig. 6 eine vergrößerte Querschnittansicht eines Teils von einem der Leichtbau-Wandelemente aus Fig. 5;
• Fig. 7 eine teilweise weg geschnittene perspektivische Ansicht eines Teils eines noch weiteren modifizierten Leichtbau-Wandelements;
• Fig. 8 eine vergrößerte Querschnittansicht eines Teils des Leichtbau-Wandelemente aus Fig. 7;
• Fig. 9 eine vergrößerte Seitenansicht eines Abschnitts einer Abschlussleiste für das obere oder untere Stirnende des Leichtbau-Wandelement aus Fig. 1;
• Fig. 10 eine vergrößerte Unterseitenansicht des Abschnitts der Abschlussleiste aus Fig. 4;
• Fig. 11 eine vergrößerte Querschnittansicht eines Teils eines weiteren, nicht erfindungsgemäßen Leichtbau-Wandelements;
• Fig. 12 eine vergrößerte Querschnittansicht eines Teils eines noch weiteren nicht erfindungsgemäßen Leichtbau-Wandelements;
• Fig. 13 eine vergrößerte Querschnittansicht entsprechend Fig. 12, jedoch mit einem wärmedämmenden Granulat in einem Teil der Kammern eines nicht erfindungsgemäßen Leichtbau-Wandelements;
• Fig. 14 eine Querschnittsansicht eines säulenförmigen Leichtbauelements;
• Fig. 15 eine Schnittansicht eines als Boden- oder Deckenplatte ausgebildeten Leichtbauelements;
• Fig. 16 eine teilweise weg geschnittene vergrößerte perspektivische Ausschnittsansicht des Leichtbauelements aus Fig. 15.
• Fig. 17 eine teilweise weg geschnittene vergrößerte perspektivische Ausschnittsansicht eines anderen als Boden- oder Deckenplatte ausgebildeten Leichtbauelements.

In the following the invention will be explained in more detail with reference to an embodiment shown in the drawing. Show it:

• Fig. 1 a partially cut away perspective view of parts of two lightweight wall elements;
• Fig. 2 an enlarged cross-sectional view of a part of one of the lightweight wall elements Fig. 1 ;
• Fig. 3 a partially cut away perspective view of parts of two modified lightweight wall elements;
• Fig. 4 an enlarged cross-sectional view of a part of one of the lightweight wall elements Fig. 3 ;
• Fig. 5 a partially cut away perspective view of parts of two other modified lightweight wall elements;
• Fig. 6 an enlarged cross-sectional view of a part of one of the lightweight wall elements Fig. 5 ;
• Fig. 7 a partially cut away perspective view of a portion of yet another modified lightweight wall element;
• Fig. 8 an enlarged cross-sectional view of a portion of the lightweight wall elements Fig. 7 ;
• Fig. 9 an enlarged side view of a portion of a terminating strip for the upper or lower front end of the lightweight wall element Fig. 1 ;
• Fig. 10 an enlarged bottom view of the section of the end bar Fig. 4 ;
• Fig. 11 an enlarged cross-sectional view of a portion of another, not according to the invention lightweight wall element;
• Fig. 12 an enlarged cross-sectional view of a portion of yet another lightweight wall element not according to the invention;
• Fig. 13 an enlarged cross-sectional view accordingly Fig. 12 but with a heat-insulating granules in a part of the chambers of a lightweight wall element not according to the invention;
• Fig. 14 a cross-sectional view of a columnar lightweight component;
• Fig. 15 a sectional view of a designed as a floor or ceiling panel lightweight construction element;
• Fig. 16 a partially cut away enlarged perspective cutaway view of the lightweight construction element Fig. 15 ,
• Fig. 17 a partially cutaway enlarged perspective cutaway view of another designed as a floor or ceiling panel lightweight construction element.

The bearing or supporting lightweight components 2 shown in the drawing each contain a multi-chamber hollow section 4, which surrounds one or more rows of chambers 6 with parallel longitudinal central axes 8 and a constant in the direction of the longitudinal central axes 8 opening cross section.

In the lightweight elements 2 in the FIGS. 1 to 10 and 14 to 17, the multi-chamber hollow section 4 consists of a plurality of interconnected cylindrical hollow bodies 12 made of paper whose outer and inner peripheral surfaces 14, 16 are coated with a resin 10 and together with the coating of the resin 10, the boundary walls of the chambers. 6 form. In the lightweight elements 2 in the FIGS. 1 to 10 and 14 to 16, the hollow body 12 are embedded in a hard foam 18 which fills the gusset 20 between the adjacent tubular hollow bodies 12 and the hollow body 12 also connects to each other.

When it is the lightweight element 2 is a wall element, as in the FIGS. 1 to 8 represented, or to a support element, for example a pillar, as in Fig. 14 Shown in cross-section, the tubular hollow bodies 12 are arranged side by side within the lightweight component 2 in a parallel and vertical orientation. The hollow body 12 of the lightweight components 2 in the FIGS. 1 to 8 and 14 to 17 lie with their outer peripheral surfaces 14 against the outer peripheral surfaces 14 of adjacent hollow body 12, so that the hollow body 12 are mutually supported.

In the lightweight wall elements 2 in the FIGS. 1 to 8 For example, depending on the thickness of the wall element 10 and the diameter of the tubular hollow bodies 12 used between two opposite broad sides 22, a single row of tubular bodies 12 arranged side by side may be provided, the longitudinal central axes 8 of which span a vertical plane, as in FIGS FIGS. 1 to 4 . 7 and 8 , or several rows, as in the FIGS. 5 and 6 shown. If the lightweight wall element 2 contains a plurality of rows of tubular hollow bodies 12, the longitudinal central axes 8 of the hollow bodies 12 in adjacent rows of hollow bodies 12 are offset by the diameter of the hollow bodies 12, so that the rows are meshed with each other and the hollow body 12 not only parallel and perpendicular to the broad sides 22 of the lightweight element 2 are supported against each other, but also at an acute angle of 45 degrees to these directions. In addition, this minimizes the volume of foam 18 filled with intermediate spaces or gusset 20 between the adjacent hollow bodies 12.

The tubular hollow bodies 12 consist of several completely or partially glued together wound layers or layers of recycled paper. Each of the layers or layers may consist of helical paper strips that are continuously wound on a mandrel so that they overlap with adjacent coils or strips, adhering to one another at the points of overlap. However, the layers may also consist of wider sheets or webs wound in the circumferential direction of the hollow body 12. The recycled paper has no special quality requirements.

In lightweight construction elements 2 in the form of wall or support elements, the tubular hollow bodies 12 have a length corresponding to the height of the wall or support element 2 and are open at their opposite ends. The ratio between the outer diameter and the wall thickness of the tubular hollow body 12 is greater than 25: 1, preferably greater than 50: 1 and is best between about 50: 1 and about 100: 1. In the latter case, the wall thickness of the hollow body 12 at a diameter of about 50 mm about 0.5 mm. The weight of the hollow body 12 coated with resin 10 prior to its embedding in the hard foam 18 is less than 100 g per meter length, preferably less than 50 g and most preferably less than 25 g.

Resin 10 used for coating is an MDI based epoxy or polyisocyanurate reactive resin or a modified epoxy or polyisocyanurate reaction resin, both of which are commercially available under the name Blendur from Bayer MaterialScience. Depending on the composition, these resins either trimerize after addition of a catalyst by the addition of heat or without the need for a catalyst by heat alone to form a highly crosslinked thermosetting resin or plastic having excellent thermal stability. The crosslinking or curing of the resin takes place subsequent to the application of the resin 10 to the outer and the inner circumferential surfaces 14, 16 of the hollow body 12, which preferably takes place immediately after the winding of the hollow body 12 made of paper.

After the trimerization or curing of the resin 10, the finished tubular hollow body 12 are introduced in the desired number and arrangement in a closable mold with a shape corresponding to the shape and dimensions of the lightweight elements 2 mold cavity, so that the open ends of the chambers 6 to the opposite Front ends of the hollow body 12 are closed by mold walls of the mold. Subsequently, the gaps or gussets 20 are foamed between the adjacent hollow bodies 12 with the hard foam 18, which consists of a PIR foam and is cured in the mold.

In order to avoid entrapment of air between the foam and the hollow bodies 12 when introducing the flowable foam into the mold, it is preferable for adjacent hollow bodies 12 to be spaced from each other, as in FIG FIGS. 7 and 8 represented, so that the flowable foam can be supplied to one side of the lightweight components 2 in the mold and from there through the gaps between the adjacent hollow bodies 12 can fill the entire mold cavity. After curing, the hard foam 18 ensures a firm connection between the hollow bodies 12 embedded therein.

The lightweight wall elements 2 in the FIGS. 1, 2 . 5, 6 . 7 and 8 are not provided at its two opposite broad sides 22 with one or two additional cover layers, so that they consist essentially only of the tubular hollow bodies 12 and the hard foam 18, which fills the gaps or gussets 20 between the outer periphery 14 of the adjacent hollow body 12 and in this case, the surfaces of the two broad sides 22 of the lightweight elements 2 forms. Here can be used as rigid foam with advantage a so-called integral foam, in which the hardness of the cured foam in the direction of the surfaces of the broadsides 22 increases.

The lightweight elements 2 in the Figures 1 and 2 7 and 8, each having a single row of cylindrical tubular hollow bodies 12 having an outer diameter of 50 mm, have a basis weight of less than 3 kg / m ² and preferably less than 2 kg / m ² . Most preferably, the weight per unit area of these lightweight elements 2 is about 1.5 to 2 kg / cm ² , the basis weight of the untreated paper being 0.45 to 0.55 kg / m ² , the basis weight of the resin used for coating being 10 0.55 to 0 , 60 kg / m ² and the basis weight of the hard foam 18 is 0.55 to 0.65 kg / m ² , so that these three components thus provide about one third of the basis weight.

In contrast, the surfaces of the opposite broad sides 22 of the lightweight wall elements 12 in 3 and 4 and the outer periphery 26 of the lightweight support member 2 in FIG Fig. 3 formed by a cover layer 28 of a fiber-reinforced resin which is parallel to the broad sides and which is applied for stiffening the wall elements 12. The resin may, for example, be polyurethane, in which a woven or scrim of glass fibers, synthetic fibers or carbon fibers is embedded. Alternatively or additionally, however, it is also possible to use cover layers of other materials, such as, for example, mineral fiber cover plates, which consist of one with glass fibers reinforced mixture of magnesium oxide and magnesium chloride, abut with their inner surfaces against the adjacent row of hollow bodies 12 and are bonded by the hard foam 18 with the tubular hollow bodies 12. Possibly. For example, the cover layer or cover layers can also be connected by screws to the core of the lightweight elements 2 consisting of the hollow bodies 12 and the hard foam 18.

The rigid foam 18 is a PIR foam, ie polyurethane foam, which is crosslinked higher than the conventional polyurethane foam and is thus dimensionally stable even at higher temperatures. Due to the dimensional stability and the relatively small pore dimensions of less than 1 mm, the hard foam 18 in the manufacture of the lightweight wall elements 2 in the FIGS. 1 to 8 be formed on the two opposite vertical narrow sides of each wall element 2 to a groove 30 and a spring 32, so that adjacent wall elements 2 by means of a tongue and groove joint 30, 32 are connected to one another.

In order to shoot the openings of the tubular hollow body 12 at the upper and lower ends of the lightweight wall elements 2 and to provide a flat finish, the lightweight wall elements 2 are each provided at its upper and lower ends with a closure strip 34. How best in FIGS. 9 and 10 illustrated, the end strip 34 has a remote from the ends of the hollow body 12 planar broadside 36. About the opposite, the ends of the hollow body 12 facing broadside 38 is a series of cylindrical projections 40, whose outer diameter is slightly smaller than the inner diameter of the tubular hollow body 12, so that they are in the open ends of the chambers 6 at the ends of the hollow body 12 can be introduced and thus improve the cohesion of the hollow body 12 at the top and bottom. In order to facilitate the insertion of the projections 40 into the opposite openings, the free ends of the projections 40 are tapered or chamfered. The end strips 34 have a length and width corresponding to the length and width of the lightweight wall elements 2 and can be mounted in the manufacture of the lightweight wall elements 2 or in the installation thereof. In the latter case, the strips 34 can each be offset from the tongue and groove joints 30, 32 are attached to the joints of adjacent lightweight wall elements 2, so that they bridge the shocks.

It has been found by experimentation that lightweight wall elements 2 having a height of 980 mm, a width of 250 mm and a thickness of 56 mm, consisting of a series of cylindrical tubular hollow bodies 12, which at their outer and inner peripheral surfaces 14, 16 with an epoxy or polyisocyanurate reaction resin 10 are coated, and two cover layers 28 of mineral fiber cover plates with a thickness of 3 mm on both broad sides and a filling of PIR rigid foam 18 in the interstices or gussets 20 between the tubular hollow bodies 12 and the cover layers 28 according to Fig. 4 in the direction of the longitudinal central axes 8 of the hollow body 12 can absorb a pressure load of more than 2.5 t before it comes to a breakage of the wall elements 10. In bending tests with the same lightweight wall elements 2, but with a rigid polyurethane foam 18 in the spaces 20 between the hollow bodies 12, it was found that the wall elements 2 at a distance at two points in one of the broad sides 22 initiated lateral pressure load of 0.4 t endure before it comes to a bending of the lightweight components 2.

The high carrying capacity of the lightweight elements 2 in the direction of the longitudinal center axes 8 of the tubular hollow body 12 is achieved by the coating of the outer and inner peripheral surfaces 14 and 16 of the hollow body 12 with the resin 10, after its crosslinking and curing the compressive strength of the hollow body 12 in the direction of their Longitudinal central axes 8 increased by a multiple.

In the in the FIGS. 11 to 13 shown in cross-section lightweight construction elements 2, the multi-chamber hollow section 4 is not one or more rows of individual, interconnected hollow bodies 12, but of two or more mutually adjacent and interconnected plates 42, each having a cross section in the form of a sine wave with alternating projections in Have wave form 44 and depressions in the form of troughs 46. The wave crests 44 and the wave troughs 46 of adjacent plates 42 are offset by a half-wave against each other, so that in each case the wave peaks 44 and the troughs 46 of the two plates 42 are opposite, with each opposite wave peaks 44 abut with their apexes 50 against each other and at the apex 50th glued together. As a result, a row of juxtaposed chambers 6, which have the same cross sections, which remain the same in the direction of the longitudinal axes of the chambers 6, is formed between two adjacent plates 42. The adjacent chambers 6 are separated from each other by the adhesive 50 at the apexes 50. The plates 42, like the hollow profiles 6, consist of one or more paper layers and are provided with a coating of the resin 10 on their inner surfaces 52 facing the chambers 6 and on their outer surfaces 54 facing away from the chambers 6, as previously for the hollow bodies 12 described. The resin 10 used for coating is the same as previously described. The wall thicknesses of the plates 42 and the ratio of the cross-sectional dimensions of the chambers 6 to the wall thickness of the plates 42, which form the boundary walls of the chambers 6, are similar as previously described for the hollow bodies 12.

In the lightweight elements 2 in the FIGS. 11 to 13 are wall elements. The wall element 2 in Fig. 11 is like the wall element 2 in 3 and 4 with two flat cover layers 28 in the form of thin mineral fiber boards or one Provided fiber-reinforced resin, which abut against the apex 56 of the troughs 46 and are glued between them with hard foam 18 to the multi-chamber hollow section 4, wherein the hard foam 18, the gusset 20 between the chambers 6 facing away from the outer surfaces 54 of the plates 42 and the Cover layers 28 fills.

While the multi-chamber hollow section 4 of the wall element 2 in Fig. 11 consists of two superimposed plates 4, there is the multi-chamber hollow section 4 of the wall element 2 in FIGS. 12 and 13 from a total of four superimposed plates 42 with wave-shaped cross-section, which delimit between them three rows of chambers 6. The chambers 6 adjacent rows are offset in the lateral direction in each case by half the chamber width against each other, so that only chambers 6, but not filled with foam 18 gusset 20 are formed between the plates 42. The inner plates 42 are in each case with the crests 50 of their crests 44 against one of the two adjacent plates 42 and the crests 56 of the wave troughs 46 against the other adjacent plate 42 and are there bonded to the adjacent plates 42. The hard foam 18 fills the gussets 20 between the outer surfaces 54 of the outermost plates 42 facing away from the chambers 6 and forms the surfaces of the two broad sides 22 of the wall element 2.

This in FIGS. 15 and 16 shown lightweight construction element 2 in the form of a plate-shaped ceiling or floor element consists of a plurality of short tubular hollow bodies 12 which in the hard foam 18 (only in Fig. 15 shown) are embedded. The hollow body 12 are vertically aligned and are in each case with its outer periphery 14 against the outer periphery 14 of adjacent hollow body 12, with which they are glued back through the hard foam 18 in the interstices or gussets 20. Here, however, it is also possible to omit the hard foam 18 and the adjacent hollow body 18 with the aid of Resin coating 10 on the outer peripheral surface 16 of the hollow body 12 to connect together. The hollow bodies 12 each have the same length and are supported with their opposite aligned end faces against parallel flat plate-shaped cover layers 28, which close the openings of the hollow body 12 on the top and bottom of the plate-shaped ceiling or floor element 2 and also increase its flexural rigidity before especially when the ends of the hollow body 12 are glued by the hard foam 18 with the inside of the adjacent cover layers 28. The cover layers 28 may be made of any suitable material. On the narrow sides of the lightweight elements 2 grooves (not shown) and springs 32 are again provided so that adjacent elements 2 can be connected by tongue and groove joints 30, 32 together.

Fig. 17 shows a cross section through a portion of another lightweight element 2 in the form of a plate-shaped ceiling or floor element, in which the open ends of the chambers 6 are closed instead of plate-shaped cover layers 28 by layers 60 of a fiber-reinforced synthetic resin 62. For this purpose, the hollow body 12 as in the ceiling or floor element 2 in Fig. 15 arranged in a dense array of staggered rows in which each hollow body 12 rests with its outer peripheral surface 14 against the outer peripheral surfaces 14 of six adjacent hollow bodies 12. Subsequently, the opposing hollow body 12 are glued together by means of the coating 10 consisting of the resin 10 on the outer peripheral surfaces 14 to form a rigid honeycomb structure, for example by supplying heat in an oven. Thereafter, the upper and lower ends of the chambers 6 at the broad sides of the honeycomb structure are closed by one or more layers 60 of the fiber reinforced synthetic resin 62 by placing a nonwoven 64, fabric or scrim of synthetic resin, glass or carbon fibers on each upward turned broadside of the honeycomb structure is placed so that it completely covers the open ends of the chambers 6. Subsequently, the nonwoven fabric 64, fabric or scrim is impregnated with the curable synthetic resin 62, which is cast in a thin layer on the upper side of the nonwoven fabric 64, fabric or scrim, and through the nonwoven fabric 64, fabric or scrim to the ends of the hollow bodies 12 penetrates where it adheres during curing. After curing of the resin 62, the two ends of all the hollow body 12, which form the boundary walls of the chambers 6 of the multi-chamber hollow section 4, firmly bonded to the fiber-reinforced resin 60 and form a lightweight component 2 with high bending stiffness.

In all cases, the tubular chambers 6 enclosed by the multichamber hollow section 4 may either be empty or contain a heat or sound insulating material, for example polystyrene granules 56, paper flakes or sand, as exemplified in part of the chambers 6 in FIG Fig. 11 shown. In the lightweight element in Fig. 9 the chambers are filled with hard foam 18.

Claims (14)

1. Lightweight construction element (2) which is capable of or is load-bearing, comprising one or more rows of parallel chambers (6), which are each surrounded by tube-like boundary walls, the boundary walls consisting at least partly of paper, the boundary walls of adjacent chambers (6) being connected to one another and forming a multi-chamber hollow profile (4) which, in the direction of the longitudinal central axes (8) of the chambers (6), has a cross section that remains constant, the inner surfaces (52), facing the chambers (6), and the outer surfaces, facing away from the chambers (6), of the boundary walls being provided with a water-repellent coating (10) and/or impregnation which increases the flexural and/or compressive strength of the paper, the multi-chamber hollow profile (4) comprising one or more rows of cylindrical hollow bodies (12), each of the cylindrical hollow bodies (12) bounding one of the chambers (6), and the chambers (6), and also the gaps or pockets (21) between the adjacent hollow bodies (12), being filled with a rigid foam (18) that connects the boundary walls of the adjacent chambers (6) to one another, characterized in that the rigid foam (18) is a hardening reactive foam material made of two or more components, specifically a highly cross-linked hard polyurethane foam, and in that the individual pores of the rigid foam are very small and have cross-sectional dimensions of less than 0.5 mm.
2. Lightweight construction element according to Claim 1, characterized in that the rigid foam (18) is applied to at least one outer side of the multi-chamber hollow profile (4) that faces away from the chambers (6).
3. Lightweight construction element according to Claim 1 or 2, characterized in that the boundary walls consist of less than four paper layers glued to one another and have a wall thickness of less than 2 mm.
4. Lightweight construction element according to one of the preceding claims, characterized in that the coating and/or impregnation consists of a thermoplastic resin (10) or synthetic resin applied to the surfaces in the free-flowing state and then cross-linked.
5. Lightweight construction element according to Claim 4, characterized in that the coating and/or impregnation consists of a polyisocyanurate or epoxyisocyanurate resin.
6. Lightweight construction element according to one of the preceding claims, characterized in that the multi-chamber hollow profile (4) comprises one or more rows of tube-like hollow bodies (12) which are arranged beside one another, which rest with their outer circumference (14) against the outer circumference (14) of adjacent tube-like hollow bodies (12) and are glued to the adjacent hollow bodies (12) by the coating and/or the rigid foam (18) .
7. Lightweight construction element according to one of the preceding claims, characterized in that the multi-chamber hollow profile (4) extends continuously over the entire height of the lightweight construction element (10).
8. Lightweight construction element according to one of the preceding claims, characterized in that the ratio between the cross-sectional dimensions of the chambers (6) and the wall thickness of the boundary walls (12, 42) is greater than 25:1 and preferably greater than 50:1 and at best about 100:1.
9. Lightweight construction element according to one of Claims 2 to 8, characterized in that the rigid foam (18) forms at least one surface (22) of the lightweight construction element (10).
10. Lightweight construction element according to one of Claims 2 to 9, characterized by an additional covering layer (28).
11. Lightweight construction element according to one of Claims 2 to 10, characterized in that a groove (30) and a tongue (32), which are moulded into the rigid foam (10) or milled out of the rigid foam (18), are arranged on two opposite narrow sides.
12. Lightweight construction element according to one of the preceding claims in the form of a floorboard or ceiling board, characterized in that the multi-chamber hollow profile (4) comprises a large number of short tube-like hollow bodies (12), of which the opposite open ends each cover a flat surface and are closed by at least one layer (60) of a fibre-reinforced resin (62, 64) adhering to the ends of the hollow bodies (12).
13. Freight or accommodation container having a floor, side walls and a ceiling, characterized in that the floor and/or at least part of the sidewalls and/or the ceiling are composed of lightweight construction elements (2) according to one of the preceding claims.
14. Rail car or heavy goods vehicle superstructure having a floor, side walls and a ceiling, characterized in that the floor and/or at least part of the sidewalls and/or the ceiling are composed of lightweight construction elements (2) according to one of Claims 1 to 12.

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