DE6601610U - HEAVY DUTY FOAM BODY - Google Patents

Description

FARBENFABRIKEN BAYER AG

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LEV ERKUS EN - Bayerwerk Pitent Department 26. 11th 1 C) 68

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Edge zone reinforcement insert for heavy-duty foam bodies

The present innovation relates to an edge zone insert for Foaming in the production of high-strength, an outer skin exhibiting foam body, consisting of at least one reinforcement material and a fiber structure.

Foam bodies with such deposits can be found in the manifold Most variations are used in vehicle construction, house construction and, among other things, in

However, there is always the demand for display material bodies that can still be used to be able to manufacture in a technically favorable manner]

There are foams off bodies as core layers of. Known sandwich constructions, whereby you get the cavity between two high strength *, u sandwich top layers scalded out. This composite construction has the advantage that the high-strength cover layers, e.g. made of metal or glass fiber reinforced plastics or thermoplastics, can be kept extremely thin, because the Schaunis fabric layer in between them folds or Bumps hindered. It is also already known these high-strength top layers on their inward facing seldom before foaming

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to be covered with tangled fiber structures to directly below the cover layers a foam with a higher density than the density of the support core interior to obtain, whereby this inhomogeneous core has a great support capacity.

It is therefore known, in the case of sandwich bodies, in the zones directly to produce a foam with a density below the thin cover layers, the density of which is up to twenty times that of the interior of the support core, which increases the crease resistance of the top layer is increased significantly.

For the production of complex sandwich bodies, such as Body parts, is a prepress to speed up production

or pre-forming of the cover layers is recommended, provided that these consist of | fiberglass-reinforced plastics, thermoplastics or bits are made || should. From a manufacturing point of view, however, this means the additional application of random fiber structures or in a further work step additional reinforcement mats on these pre-pressed parts an expense, which, for reasons of economy, can only be used for special constructions or small series.

According to another method, a vorbekaniiten optionally armored with fiber reinforced plastic prepolymer _s so-called glass-fiber prepregs, for example, are made based on epoxy resin or unsaturated polyester based resins, defined as sin mats in the Fora. The foaming temperature and the housing pressure of the resulting show cause the final polymerisation.

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This is particularly successful with complex foam bodies Use of this process is limited, since the final polymerization of the prepregs is probably sufficient with the foaming reaction that takes place is controllable, the discharge of the unavoidable between prepregs and Pormvrandung Air layer is only possible through porous and therefore complex shapes.

According to a further known method, the cover layer is produced using the hand-rest lamination process, in that reinforcement mats, preferably glass fiber fabrics, are laid one on top of the other in several layers on the inner surface of the foam mold coated with a binding agent. With a brush, polyester or epoxy resin is dabbed into each fabric layer by hand, making sure that any air from the reinforcement mats is displaced by the dabbed resin. Such manual work is of course very time-consuming and forbids axxs Profitabil it for reasons of single application.

All of these procedures are used in practice and are for individual use cases are quite suitable. Another spread, especially for the series production of heavy-duty foam Bodies were denied to these previously known methods because of the inadequate feasibility in terms of manufacturing technology. A Ranäzone reinforcement insert has now been found, which the manufacturer of foam bodies under favorable manufacturing technology

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Conditions allowed and at the same time the highest static and dynamic Strength values of the foam toi '. "" Body guaranteed. This innovation-compliant Edge reinforcement insert is characterized, that the fiber structure is firmly anchored in the reinforcement mat.

According to this innovation, the use of a preformed Top layer dispensed with vferden, Όζυϊ. in combination with high strength Top layers can also be very heavy-duty sandwich structures getting produced.

While the previously known cdi foam are made up of nonwovens in a second step: "the reinforcement mats were glued on, the invention assumes the pasers of the random fiber structures to use directly for power transmission by firmly with the reinforcement mat, e.g. fabric.

When using a single reinforcement mat (e.g. fabric) with a single fiber structure, a spatial, long-fiber random fleece is preferably selected as the fiber structure, which on the one hand is carefully connected to the fabric and on the other hand with its free fiber ends extends far into the foam core, so as to enclose the entire reinforcement system in the foam core anchor. It has been shown that in the case of components of the same weight with such an edge zone reinforcement insert in combination with the foam core, highly stressable foam bodies with at least as high a strength as for a conventionally produced sandwich construction , consisting of high-strength prefabricated cover layers and foam support cores, produced in the well-known filling construction.

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The innovation should therefore be the elaborate prefabrication of top layers make them superfluous or, in combination with top layers, even better strength properties through optimally designed sandwich support cores for heavy-duty sandwich constructions.

In the context of the innovation, under "outer skin" in the broader sense is a To understand cover layer made of metal, glass fiber reinforced plastic or prepregs. In the narrower sense, the outer skin consists of an elastic one Binder primer, so-called gel coat, preferably based on polyurethane, with which the previously coated with a release agent Inner wall of the foam mold is coated. This binder ' vorstrich serves both as surface protection and for gluing the reinforcement system and should be so thick that no fibers of the Reinforcement mat protrudes outwards to prevent surface corrosion To prevent capillary action.

As reinforcement mats, which in the reinforcement system according to the innovation, the high tensile and compressive stresses in the foam body edge zone have to absorb, come in a manner known to me the foamable ones Fabrics in question, such as fiberglass fabrics, fabrics made of synthetic fibers or wires, wire mesh and wire mesh inlays, Textile fabric, metal skeletons or plastic skeletons. Of course Combinations of such reinforcement mats are also included, such as a glass fiber mat with wire mesh insert

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AIs fiber structures are used predominantly spatial random fiber webs application, but AUOH Kräuselkreppgeviebe, and even loose fibrous tissue.

Depending on the stress on the foam body according to As a result of the innovation, the thickness of the reinforced edge zone can now also be increased. According to a particularly advantageous embodiment The invention also includes several reinforcement mats with several fiber structures arranged alternately one above the other, the fibers of the Fiber structures are firmly connected to the two adjacent reinforcement mats. With such a "construction of the edge zone reinforcement insert a three-dimensional framework is produced in comparison, which is filled by foam after the foaming process and has corresponding strength properties. Simultaneously with the The construction of this reinforcement insert is made through appropriate selection of the fiber structures in terms of their weight per unit area, thickness and fiber strength Fiber density, degree of tangle, etc. the density of the foam that is formed within the respective fiber structure is determined. Through this double if the reinforcement insert it is the designer in the Hand given to give the foam body a desired density in its edge zone, which leads to the desired strength of the overall construction contributes, at the same time to the transmission and absorption of the transverse forces between the various reinforcement mats also the Fibers of the three-dimensional fiber structure are also used.

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Corresponding to the wide range of options for reinforcement mats and fiber structures, the new foamed fabric body can also be made in the most varied of shapes. In general, a decrease in density of the foam from the edge zone to the inside of the core has wrinkled , > 7obsi the decrease in density in the various fiber structure layers is almost continuous. For structural reasons, however, any other density curve can also be selected. On the one hand, the fibers for the fiber structure can be freely selected with regard to their strength and, on the other hand, the fibers can be used in the desired thickness _{3 in} order to influence the foam density. As a first approximation, the foam density increases with increasing weight per unit area and increasing thickness of the fiber structure as well as decreasing titer number of the fibers. Another essential factor for the show density is the foaming pressure that prevails inside the mold during foaming. With the known foaming method, he does not need to increase the foam density over the entire foam body cross-section. Of course, the density can also be influenced from the chemical side by correspondingly varying the formulation of the reaction mixture without changing the total weight of the structural element. Taken all together - foaming method, choice of recipe and the choice of fiber structure and the firm connection of your fibers with the reinforcement mats - allows the designer to influence the density distribution in the foam body accordingly.

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According to the innovation, such a foam body can be constructed, for example, in such a way that the foam has an approximately and continuous decrease in density from, for example, 1.1 to 0.02 g / cm from the first fiber structure towards the center of the core. Such a high drop in density had not been achieved with the known foam bodies. In the first fiber structure, i.e. between the first and second reinforcement rat, the foam density drops from 1.1 to 0.6 g / cm · ^, in the second bevel structure from 0.6 to 0.1 g / cm and from the innermost one Reinforcement mat towards the core interior η from 0.1 to 0.02 g / cm- ⁵ . The side of the innermost reinforcement mat facing the inside of the core is reinforced with a three-dimensional tangled fiber fleece, the fiber system of tangled or curled, very open and therefore easily foaming tangled fiber fleece made of natural octer synthetic monofilament, which provides resistance from the blowing process of the reaction mixture Very thick threads with a diameter from OI to UJ se and a length ν ort 10 to 30 mm and longer.

This creates a foam with an ideal density construction that is comparable to the natural one, for example Structure of an elder or a bone. The effect of the self-generating different density is based on the The fact that the reaction mixture penetrating into the fiber structure collapsed by the fibers, i.e. foam formation is delayed. The unhindered outdoor space; The foaming reaction mixture pushes further liquid components into the fiber structure a. "Since the free interior now runs through unhindered Reactions is under excess pressure, this still liquid, creamy foam is the same as that which foams up in the fiber structures with a delay

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Shuts off the reaction mixture and therefore compresses the proportion of the reaction mixture "swallowed" by the fiber structure to a greater extent. It is
those still present in the foaming mold in the area of the fiber structure
compressed air and the cell gas that is also released there
of influence, since the edge zone air and cell gas are under the overpressure of the
Foam inside can be transported into the freely reacting foam core inside and to an additional increase in the active effect
Core foaming pressure used wc "den can.

The fiber structure closest to the inside of the foam body
consists in an advantageous manner of a spatial, long-fiber
Random fiber fleece that is firmly connected to the reinforcement mat. the
Fibers should be as long as possible in order to anchor the hearing ;
To ensure matt depth in the foam body. This random fiber 1

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Nonwovens, e.g. made of fine-fiber acrylic fibers, are un |

P Roll out the edge zone reinforcement insert or before foaming esa.

I brushed shape so that the fibers are at least 10 to 20 mm woolly in |

protrude into the space to be foamed. With this post-treatment it could be demonstrated in dynamic tests that with alternating bending, | stress of the foam body in no case pressure fractures of the tra-.
shells due to premature kneeling, but only tensile breaks
entered. The excellent deep anchorage, ζ “3. by brushed up
Anchoring fleece, it allows the. According to the innovation foam .jj material body only on the tensile strength of the reinforced outer shell
to dimension.

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The effect of the deep anchoring can also be optimized «, that the anchoring fleece is not made of fine-titer fibers, but of Coarse-denier fibers, e.g. based on polyamide, can be used if necessary and, if the component thickness permits, 10 to 30 mm and longer and have a basis weight of more than 250 g / m 2.

According to a further development of the innovation, the interior of the foam mold is completely or partially filled with very voluminous, well-foamable tangles / fleeces which are only fixed in themselves by crimping and which can now have thicknesses of 20 to 30 , whereupon the voluminous fleeces pass through when the form is closed Compression are brought under a certain bias and thus forgive each other in the reinforcement insert so that they cannot be displaced from the intended position during the "foaming process the rigidity of the overall construction according to the innovation.

example

It was used when testing an innovation-compliant foam body found that with the same total weight as a sandwich construction, the basin layers made of glass fiber reinforced plastic, e.g. epoxy resin, made by pressing or hand lay-up a density of 1.6 g / s ^ and a thickness of 2 mm, with a glued on Glass fiber reinforcement mat with depth anchoring fleece of 450 g / cm and a foam support core based on polyurethane with a Rauisgewlcat of 90 kg / nr ^ in. Conventionally in the foaming process was made in fill construction, the same torsional stiffness

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if a reinforcement insert consisting of two layers of glass fabric with a weight of 900 g / m ^ each and 2 layers of acrylic fiber fleece with "each 160 g / m ² (alternately layered) is rolled into a pre-coat of 0.5 mm thick epoxy resin is. the inner acrylic fiber non-woven brushed v / urde and the thus finished mold is ausgoschäumt with the total weight of the reference structure corresponding polyurethane Reaktionsgeinischmenge. the summary density of the reinforced outer foam shell generated in Schäumdruckverfahren at three times the compression of the foam body was 0.8 g / ce ? and showed a continuous decrease in density from 1.1 g / cm to 0.6 g / car over its thickness of approx. 5 mm 5 oi ^§ " ¹ ^ ^ ⁵ " determined. The inside of the core had a density of 0.06 g / cm.

The comparison of the production hours for the conventionally manufactured sandwich plastic construction and for the described new foam body according to the requirements was 5: 1, which shows the importance of the innovation for the mass production of highly stressable plastic bodies, such as vehicle bodies. It is also significant that faserarmie for the production of in the edge zone: ten heavy duty foam structures now only the tr ei ': capable reaction mixture, for example based on polyurethane alone as an "active ^r production means producing the supporting reinforced outer shell and the generation of the the lightweight material core that supports the load-bearing shell.

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It is also significant that the associated 3AU of Schäumiormstützvorrichtungen which are dimensioned atmospheres, if necessary and depending on the type and GröSe of the building for a foaming pressure to I5 .nüssen, in a simple V / else by thin decrease. Forra shells, for example made of polyurethane, epoxy resin, polyester resin or metal, can be made from a structural model and these inherently unstable contour shells can be supported, for example, by a stable, solid, contoured reinforced concrete shape. _# ' _:

The foam body with the reinforcement insert |

with a high load-bearing capacity can also be used for the generation of ί ·

Sandv.'ich support cores for very large building structures | or vehicle construction, if for reasons of component parts

very high quality and thick sandwich top layers, e.g. made of 2 {. '

up to 5 mm steel or light metal sheets or from 10 mm thick glass |

fiber-reinforced plastic sheets over a large area against local dents j _:

should be stabilized. The khitter tension of thick-walled | ^;

Sheets over 2 mm thick, e.g. for large components such as binders, ) _:

Walls, shells of structural engineering as a result of the very ■

i economical production technology as cover layers for sandwich

Constructions are aimed for, can through the high-quality support ' Cores grown up to material strength. .

A foam body with the new reinforcement insert '

can also be used for very highly stressed transverse ι by bending and torsion

Sections or connection zones Locally by additionally arranged j

high-strength outer layers should be reinforced so that based on the whole |

Structure a combination of a pure foam construction and a sandwich construction is present.

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Such a schaunis fabric body is found in a particularly advantageous manner Applicable as vehicle bodies, such as car bodies, airframes, Hulls and hulls.

The reinforcement mats are firmly connected to the fiber structures according to the invention by needling. Reinforcement mats and Paser structures are used for this purpose placed one on top of the other and worked the fiber ends of the fiber structures into the reinforcement mat by means of a needling machine, where they anchor themselves. In the case of multi-layer reinforcement inserts, the Faiser ends with sufficient length also through several reinforcement mats and Barrel structures are pulled through. This gives a particularly high Eligibility.

According to another embodiment, the fiber ends are on the reinforcement mats glued. However, this creates the risk that the openings in the reinforcement mat will be glued and the reaction mixture is prevented from foaming through the mat. On the other hand, it becomes too little When glue is applied, the fiber ends adhere poorly to the Arination mats. This type of bonding should not be confused with your well-known gluing of fiber structures on the inside of cover layers or on the inside of resin-impregnated reinforcement mats, since in the present application the foam that forms is the adhesive bond must be able to penetrate.

According to a further embodiment, the fiber structures are on the reinforcement mats pinned on by sewing or stapling. The seams can run like a quilt or when using Brackets can be arranged like in upholstered furniture, so that

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Application purposes can be that the edge zone reinforcement insert no longer has homogeneous strength ;. On the other side I ^ caber precisely in this regard a further possibility of variation for the designer c to optimize the deep anchoring.

Another particularly favorable embodiment shows in the Ann mat woven fibers. These can consist of foreign fibers or the ends of long fibers of the material of the reinforcement mat

Another embodiment shows the use of electrostatic flocked, coarse-meshed reinforcement mats, creating the interlocking with the fiber structures is significantly optimized.

A drawing is used to show the renewal device reinforcing the edge zone on a foam body in several embodiments shown in cross-section in extracts in Figures 1 to 3:

In FIG. 1, the entire edge zone reinforcement insert 2 is glued into the outer skin 1 consisting of a binder precoat. It consists of the reinforcement mat 3 »with which the fibers H of the fiber structure 5 are firmly connected. With 6 the foam core is referred to.

In Figure 2, the edge zone reinforcement inlay 2 consists of several Layers of reinforcement mats 3 and Fas he ge form 5 # their fibers 4 with are firmly connected to the neighboring reinforcement mats.

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In FIG. 3, an edge zone reinforcement insert 2 is pressed into the binder fabric 1, the reinforcement ^{panel 3 of which is honored with} a long-fiber, regionally woven veneer 8, the fibers of which extend deep into the core of the facing material.

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Claims (8)

It t l> Ii it 1111 B · »SB a» I »SS ■ ·· £» · ι - 16 - Protection claims: 1. Edge zone reinforcement insert for foaming during manufacture S, heavy-duty foam body with an outer skin oer j; in particular made of polyurethane; consisting of at least one armature I] rungsmatte and a fiber structure, characterized in that the I fibers (4) of the fiber structure (5) in the reinforcement mat (3) are anchored. 2. Edge zone reinforcement insert according to claim Λ, characterized in that several reinforcing mats (J) with fiber structures (5) I are arranged alternately one above the other, the fibers (4) of the I fiber structure (5) in each case at least with the two neighboring ones I reinforcement mats (3) are firmly connected. ff 3. Randzone starlcungseinlage according to claims 1 and 2, da-I characterized in that the inside of the foam body on I next to lie coming fiber structure from a spatial, long-1 fibrous random fiber fleece (7) consists. 4, edge zone stiffening insert according to claims 1 to J, thereby characterized in that the reinforcement mats (3) with the fiber structures (5) are needled. Le A 10 760-Gbm t 1 » > ς »■ . 5- Ranizoncnverstärkungseinla ^ e according to claims 1 to y, characterized in that the Paser ^ ebilde threads (3) Rait inren fiber ¹ (4) of the reinforcing mats (? J) adhered; are. 6. Edge zone reinforcement insert according to claims 1 to s>, characterized in that the paser structures (5) are attached to the Arinieruri & smatten [j) by seams or clips. 7. Edge zone reinforcement insert according to claims 1 to J, characterized in that the fibers (H) in the reinforcement mats
(4) are woven in. 8. edge zone reinforcement insert according to claims 1 to 7, characterized in that the reinforcing mats (J) have an electrostatic flocking. Le A 10 760-Gbm