DE2253323C3 - Fiber composite system for the edge zone reinforcement of highly stressable foam moldings - Google Patents

Description

Vl 53 323

borrowed, whereby thin to foam molding! inside controlled decrease in density is enforced. Such a "depot" sandwich mat allows sandwich-like To produce foam molded body. their impregnated fabric surface as a sandwich top layer is to be classified, while foamed-through fleece components and core interior as »Structural sandwich fabric with a high modulus of elasticity are to be evaluated.

For the preparation of a foaming process in the filling construction, it is from the German Offenlegungsschrift 21 04 585 known, the "Depot" sandwich mat using a Unterdnick process in the foam mold to fix that after pre-spraying a dependent on the m * -weight of the fabric component the correct amount of impregnating resin on the foam mold halves the fabric component of the depot sandwich malls is thoroughly impregnated, while the two fleece components of the »Depotw sandwich mat for the subsequent foaming process for the desired * ° formation of the structural support core from the fabric impregnation resin to remain impregnated.

The combination of the procedure of the German Oifenlegungsschrtft 21 04 585 with the one described The edge zone reinforcement system results in a method for technology »5 of the entire» depot «process that is carried out, for example, in the following operations:

a) Providing the foam mold with release agent.

b) Applying (brushing or spraying) an optionally colored gel coat layer (e.g. 300 ~ g 'm ² ) based on an unsaturated polyester resin, which, depending on the formulation, can be polymerized in 5 to 15 minutes.

c) Applying (painting or spraying) an impregnation ^{resin (e.g. 800 g'm 1} ) based on an unsaturated polyester resin.

d) Application of the fiber carpet with density variation according to the invention, the fabric or mat component ^{weighing 800 g / m 2} and this component of the fiber reinforcement system being placed on the still "wet" impregnation resin pre-spray.

e) Covering the inner surface of the mold pretreated according to a) to d) with a vacuum cloth or optionally prefabricated contoured vacuum preform z. B. based on polyurethane elastomers.

f) Applying a vacuum that is effective between the fiber system and the vacuum deformation, whereby the fabric or ^{mat component (800 g / m 2} ) of the edge zone reinforcement system is completely penetrated and vented by the 800 g / mMOIyesterharzvorspritzung.

. The vacuum remains depending on the formulation of the polyester impregnation resin and the size of the closed creating the building structure for 10 to 15 minutes until the impregnating resin has polymerized through is.

g) Lifting off the vacuum preform.

h) closing the foam mold and filling in the foam reaction mixture z. B. based on polyurethane in the closed foam mold, the amount of the blowing Pi / Ä reaction mixture of the Size of the component to be produced and the desired final density of the foam body

has to speak and the filling should be done in a single operation if possible.

The recipe formulation for the propellant Ρί / Λ reaction mixture is to be chosen so that, for. B. after 20 seconds the entry process is finished, after a further 40 seconds the entire foam cavity is filled with a still creamy liquid foam and for another 30 to 60 seconds the desired hydrostatically effective foaming pressure (1 to 3 atmospheres) is created, the complete Penetration of the fine and coarse denier fiber template causes and thereby the above-mentioned desired Density evanation of the now fiber-reinforced foam body surface is achieved.

However, it has been found to be disadvantageous for the desired high-strength foam lightweight construction that when the fabric component is impregnated through (single and multi-layer with the same layer or increasing weight towards the foam core) by means of the vacuum technology mentioned above, due to the necessary needle punctures in the Depotw sandwich mat, an uncontrollable amount of resin penetrated into the first fine-denier fleece component and an overdosage of the impregnating resin had to be made. It was z. B. a resin pre-injection of 500 gnrr (based on the foam mold surface) for the glass fabric component of the "Depot" sandwich mat of only 300 g / m ^{2 is} required in order to achieve at least 36 percent by volume of glass fiber in the impregnated glass fabric area. The Ε-module of the foam molded body cover layer on which the sandwich statics is based therefore had to be restricted ^{to a maximum of 100,000 kgf / cm 2.}

The object was therefore to create a fiber composite system of the type described above, by which the strength of the foam construction can be increased without the (glass) Fiber / resin ratio is worsened towards the higher resin content and without the bond between The outer layers and the core are deteriorated, and thus by a higher proportion of glass fabric in percentage by volume the Ε-modulus of the fabric-reinforced surface of the foam molded body is essential to increase.

This object is achieved according to the invention in that in a fiber composite system described at the outset for the edge zone reinforcement of foam structures with at least one top layer, such as sandwich constructions with a foam support core that is seen from the inside of the foam body is constructed from

a) a layer of several layers of fleece, the fiber diameter of which decreases from layer to layer,

b) a layer of several layers of fabric with a total square meter weight of 200 to 2500 g / m ² ,

whereby a) and b) are needled together, the first fabric layer made of a very fine-meshed bidirectional fabric layer with a weight of one square meter from 50 to 100 g, which is finer than the other layers of fabric.

For z. B. a total of 10 layers of the fabric component of the "Depot" sandwich mat can, depending on the statics of the foam construction, 9 layers of glass fabrics with z. B. a m ² weight of 300 g / layer and, if necessary, different tear strength

in the weaving direction. These nine layers of fabric is the core towards the inside - that is adjacent to the fine denier nonwoven component of the "depot" -Sandwichmatte - one the impregnating blocking very fine mesh bidirectional Gewebeiagc with an m ² weight of 50 to 100 g assigned. This multi-layer fabric component is needled with the aid of the fibers of the coarse denier nonwoven component with the fine denier and fine denier nonwoven component which is pre-needled.

When using the special fiber composite system, in particular due to the very fine fabric layer of low titre contained therein, the uncontrollable penetration of the impregnating resin into the fine-denier non-woven component mentioned above during the vacuum impregnation process is prevented and the required amount of impregnation resin is also limited. For a glass fabric layer quantity of 2400 g / m ² (6 layers of 400 g / m ² each) plus I layer of 100 g / m ^{2 of} fine fabric, only 1500 to 1600 g / m ^{2 of} impregnating resin are required in order to to achieve an optimal and bubble-free impregnation process for all fabric layers. A vacuum of at least 0.83 ata should be applied. The fine fabric blocks the uncontrollable outflow ^a 5 of the impregnating resin (via the many needle punctures necessary for the needling) into the fine-titer fleece layer and instead forces the impregnating resin, which is under negative pressure, all the gaps between the many fabric layers with an ^{individual m 2} weight of preferably up to 400 g / m ² to meet.

The Ε modulus of the resin-impregnated fabric component as a molded foam body cover layer is increased in this way to 150,000 to 200,000 kp / cm ² . The glass fiber content is 58 to 60 percent by volume. By the way, in accordance with the »Depot« technique, the very critical risk of delamination, which can occur for a simple hand lay-up process or for the pressing technique of GRP skins , is completely prevented by the needling of the »Depot« sandwich mat.

The high percentage by volume of the fabric in the impregnation area of the »Depot« foam construction now means that with an increased modulus of elasticity the surface of the molded part is thinner and therefore thinner lighter skin than before as a sandwich top layer can be used as a basis for the statics.

Following the sandwich lightweight construction concept, it is now necessary to use the "depot" method to achieve the supporting effect produced structure foam So (Füllbauwcise) to optimize so that the now producible thin high-e-modular top layer (0.2 to 3 mm) for all loads corresponding to the statics of the precast element in the case of creasing with the material strength z. B. a very thick-walled (50 to 100 mm) GFÄ "construction can be equated.

This means the need for a special construction of the fleece layers of the entire fiber composite system with regard to the amount (g / m ² ) of the fine-fiber and coarse-fiber fleece to be needled with the required fabric layers, which is required to obtain the structural effect of the support core with one of the fabrics - Foam through the impregnation resin layer according to the amount of foam 711.

It was found, for example, that for a glass fabric / impregnating resin thickness of 2 mm (glass content = 60 percent by volume) a fine-fiber fleece of 300 g m ² and a coarse-fiber fleece of 150 g / m ^{2 is} required and the dosage of the foam fill quantity == 110 kg / m ³ (based on the remaining cavity between the fabric / impregnating resin skin.

For a glass fabric / impregnating resin thickness of 3.5 mm (glass content 60 percent by weight), a fine-fiber fleece of 350 g / m ² and a coarse- ^{fiber fleece of 200 g / m 2 are} required, and the dosage of the foam fill quantity must be 130 kg / m ³ be.

With the two special constructions mentioned, it is achieved that the support effect of the sandwich support core reinforced in its surface by the foamed fleece is optimal and the thinner high-E-module fabric / impregnation _resin top layer on i knee = 1300 kp / cm * = 0 , 87 _{? Pressure} = 1500 kp / cm- can be measured.

Another variation of the fleece component a) of the fiber composite system ("Depot" sandwich mat) to optimize the structural effect of the sandwich support core is particularly useful for fabric / impregnation resin thicknesses over 2 mm with high modulus of elasticity. If a titer of 7.6 dtex was chosen for the fibrous fleece component and a titer of 60 to 100 dtex for the coarse-fiber fleece, it is practical ₍ to assign a fleece intermediate layer with about 17 to 20 dtex in order to use these 3 fleece components to reduce the density of the to make the reinforced support core surface even more continuous.

For example, for a 3 mm Gcwcbc / 'impregnating resin thickness the following fleece variation is appropriate:

200 g / m ² fleece with 7.5 dtex, 150 g / m ² fleece with 20 dtex and 200 g / m ² fleece with 80 dtex. In this case it is to be combined with a foam filling quantity of only 110 kg / m ³ .

There is also the possibility of ^{increasing the amount of fabric to 5000 g / m 2} by performing the negative pressure process outlined above twice with the needle-punched sandwich mat made of 2500 g / m ² glass fabric + fine-denier nonwoven -f- coarse-denier nonwoven.

For the second impregnation process, the exposed fleece components are then impregnated of the first sandwich system and the fabric layer of the second sandwich mat about 20% more impregnation resin than to choose for the first vacuum process.

Finally, it is also possible to use metal fiber nonwovens, preferably with an m ² weight of 100 to 200 g / m ² , in the fiber composite system.

Claims (1)

Fabrics with layer weights of 80 to 800 g ; _m i are used. There can also be their combined patent claims: nations and, if necessary, additional metal fabric Fiber composite system for the edge zone ^{reinforcement VCI} rCc "v He's" made of fine-denier fibers is preferred tion of foam structures with minde- ^ ^ _{he [regard} fibers, such as poly- at least one cover layer, such as sandwich construction, _{po | vester} . _or polyamide fibers with a tions with foam support core, - from the foam ^ ;; ' _oße \, _on '-> manufactured up to 10 dtex and has depending on From the inside of the fabric - built from g ^ _pruc i _1U nosart of the foam to be reinforced a) a layer of several layers of _{fleece, the surface of which} | _äcne a m - weight from 100 to 500 g ^ The fiber diameter decreases from layer to layer, _Wah , _this structure means that after the b) a layer of several layers of fabric with _through- foaming the Schaurr reinforced by the Vl.es, -a total square meter weight of 200 _fabric . _T eilzone a density bs 0.4 g-cm * and E-Modulbis 2500 g / m "-, δ values 10000 Kp / cm * possesses and by the raser- ^& '. taking into account the statics of the fiber-optic where a and b are needled together, d a - 15 reinforcement is essential. characterized by that the first k »^; ^ Gbl ener very fine-mesh oidireK- l --- "V ^ hih F characterized by that ^; ^ Fabric layer made from a very fine-meshed oidireK- l --- "V ^ _{or from} synthetic fibers, pre- tional fabric layer with a Quadratmeier- ^ ^ser '.'. p _o | _{yamid fibers} exist and should be special Weight of 50 to 100 g exists which fe.nma- ^ ^s * ^ei ^ ^U _amid f _Fa scr with a titer of _ä 60 dtex is schiger than the other fabric layers. mr J ^^ J. ^ _{vQn 70 to} , _{50 g} . This fleece Tvp of the fiber reinforcement system is used in the foam prefabricated fabric as an anchoring system for the highly sayings with fabrics or mats and the fleece 25 made of fcintitrisen fibers reinforced foam upper The invention concerns a fiber composite system made of ^^ ^m ^^^^ _yslm w, rd today several layers of woven and non-woven fabrics of the kind ü ^ie ** ™. _{(The practice for the} surface as already successfully described in the generic term of the claim "^^^ _Lei chtbau-For _m - is. It is mainly used to reinforce highly stressed f ^ ¹ """^ ⁰ " ^h _n ^O s ^ _ms ^P _to ffen for vehicle construction, claimable sandwich constructions with foam eden au ^ rttn ^ ™ _{ßau yon} , ^^ fabric support core and foam constructions. for house building tiemeiuc u Such an edge zone armature has already been used. system (so-called »Depot« -Sand _W ichmaUen) The in_your ι D so-called ..De- made of needle-punched mat components made of woven fabrics with a ^con ^ ^tlu ' ^1C "*. ,, full plastic body er / eunt , (Glass fibers or synthetic fibers) and various- 35 ^^^ Αϊβΐζί ^ ΰ like fiber fleeces, de a one-sided defrosting ^u . "d ^ze ~ ^s ^ ^h ^ _and torsional stiffness Possess fiber accumulation suggested. D.eses edge- an optimal bend u one of the zonenarmierungssvstem has a defined arrangement ", -g low ^ construction" ^ ew chtjine "ν dtr well? the layer components (tissue and / or surface to the Nerninneic Manes and fleeces), which are chosen so that the fiber 4o decrease in density besuzer > de ™ ^ p ^, ^ 'mt density over the thickness of the fiber composite system (in the area of the ™ t unsat f ^ '°' ^ ^ter ^ ^Z " ¹ ^ decreases on one side, ie as edge zone armored epoxy resin, with H * ^m "* ^ ™^ ^ £ _T ⁿ ° £ rungssys-.m for a foam cyanate 'mpragnier cn G ^ ^be ^ P ⁰ ^ ^e ™ »£ This has shaped bodies - from the surface of the pot-sandwich mat, the impregnated tissue starting from the later foam body - the after- 45 ^ -or C ^^^^ «^ the following positions of the individual components: a) one (in the area of the aurcnscnam ι Layer consisting of one or more layers of fleece component of the », ^^^^^ Fabrics and / or mats, b) a layer consisting of y ,, = 0.15 to 0.1 g / cm »^ f ^ere ' ^{ch dcr} """ J ^ ^ from one layer of fiber fleece made of fine-denier fibers and the second coarse-grained ^V ' ^iesko J ⁿ ~ i ^ _n c) a layer consisting of a layer of fiber-fleece 50 pot "-Sandw.chmatte) for not fiber-poor made of acquired fibers, foam core interior with y _t = 0.08 to "αΓτΪΞροΞΙ (fabrics and / or mats 0.05 g / cm * are to be marked. Da be, jann ■ according to as well as the two layers of non ^{-woven fabric) are in the older proposal, the G} ^ i ° ^ ⁿ ^ ^d "coherent composite system dun h Vernade," Depot "-Sandw, chmatte 1 - and multi-layer em ^ Iniux is united ⁵⁵ by needling with the adjacent one ^S dd ^ bchbaren roughly ux is united ⁵⁵ by needling with the adjacent one F ^S ÜR the surface with these fine denier Armierungssyste- web and the adjacent n ^ coarse The later foam bodies provided with the titrated fleece are supposed to be united. The Trtervanat on the Vhcse Gb d Mttlgen or their combination and their purchase (m ^ -weight .η ^ m) determined The later foam bodies provided with the titer fleece should combine fabric or mat layers or their combination and purchase (m ^ -weight .η soaked with unsaturated polyester resin, epoxy resin or polyurethane ^{according to the older νο} ^^ ^{α resin or} ° of generated foam-K; required to take, usually glass fiber reinforced full amount treibfahig ^ _of; can tolerate n systems the fleece components in Reaktionsgem.sches that ^z ".. J"^^^;. by foam sihäumprozeß have both the on-fleece components and for. ^Βΐ1 ^. ^η 8 ^ ₀ ^ ™ ^ ^η would be the foam zone lying on the outside to be required w.rd the expanding foam reaction to solidify as well as the entire stressed fiber * 5 mixture collapse during off "HAUM-Vcrgaτ. 5 · η AbVerbundsystem in the supporting core-depth anchor. hängigke.t of the various non-woven structures as woven or mat layers can be glass-Ge- (feintitrig and high m-weight = y _rl or coarse asbestos fabric (resp. -Mats), synthetic titer and lower m ² -Weight = y _r2 ) different-