DE102006062248A1 - New prepolymer obtained by using di- or poly- functional organic cyanate, di- or poly- functional aromatic alcohol, di- or poly- functional aliphatic compounds and filler material, useful for the preparation of molded or layered body - Google Patents

Abstract

Prepolymer, obtained by using at least a di- or poly- functional organic cyanate, at least a di- or poly- functional aromatic alcohol, at least a di- or poly- functional aliphatic compounds and optionally at least a filler material, where: the aliphatic residue contains at least a fluorine substituted alcohol, the molar ratio of the cyanato group to hydroxy group in the initial material is 95:5-70:30; and the resin exists in a cross-linking degree, is new. Prepolymer obtained by using at least a di- or poly- functional organic cyanate, at least a di- or poly- functional aromatic alcohol, at least a di- or poly- functional aliphatic compounds and optionally at least a filler material, where: the aliphatic residue contains at least a fluorine substituted alcohol, the molar ratio of the cynato group to hydroxy group in the initial material is 95:5-70:30; the resin exists in a cross-linking degree, which is less than the gel point; and the prepolymer is not produced from the dicyanate derivative of bisphenol A, bisphenol A or its brominated derivative, 4,4'-thiodiphenol with out any filler material, aliphatic dicyanate and diol, is new. An independent claim is included for molded or layered body, obtained by hardening the prepolymer at increased pressure and temperature.

Description

The The invention relates to the use of a resin matrix for the production a polymer film for surface coating of fiber-plastic composites and a process for coating fiber-plastic composites, which are produced using prepreg.

Fiber-reinforced plastic materials be due to their favorable characteristics like theirs low weight and high tensile strength in wide ranges used in aviation technology. So they are z. B. in the interior used by passenger aircraft. These so-called interior components such as sidewalls or hatrack flaps need have a special surface quality, because they are directly in the field of vision of the passengers.

Around the best possible mechanical properties if possible To achieve low weight, the components are usually produced as a sandwich construction. Honeycombs are made of phenolic resin impregnated Paper (known, for example, under the trade name Nomex honeycomb) used as a core and thin layers of prepreg.

prepreg denotes a semi-finished product, which consists of continuous fibers and an uncured thermosetting plastic matrix. The continuous fibers can as a unidirectional layer, as a tissue or as a scrim. usual Fiber types are z. As glass fibers, carbon fibers or aramid fibers. Glass fibers are common.

The Plastic matrix contains a mixture of resin and hardener and optionally accelerators. The hardener and if necessary the accelerator determines the curing temperature, d. H. the temperature at which the curing process begins.

The Matrix systems are based on their curing temperature and the resin type.

to Production of the sandwich components are several different procedures used. In the methods, the component is replaced by fitting the above construction in the mold and curing in of the form.

in the Vacuum bag process, prepreg is first placed in the mold, then the honeycomb and then prepreg again. Form is then placed in a vacuum bag and vacuum is applied. When the structure has adapted to the shape, the mold is heated, to start the cure. The starting temperature depends thereby from the used matrix system.

A Another variant of the vacuum bag method is the so-called autoclave method. Herein, the evacuated vacuum bag containing the structure is filled in an autoclave under elevated pressure and elevated temperature hardened.

in the Hot pressing process is the construction of prepreg honeycomb prepreg placed in a heated mold and pressed under pressure. In contrast to the vacuum bag method, the shape is already here the temperature required for curing, so that the sandwich structure are made prior to insertion into the mold got to.

Flame resistance plays a major role in aerospace components, especially interior components. Flame resistance is the property of materials, products or components to withstand the effects of flame or ignition sources, or the ability to prevent the spread of fire by energetic, kinetic, chemical or mechanical means. The term is not standardized and the property as such can not be measured (cf. Römpp-Lexikon Paints and printing inks; Ed. U. Zorll, Thieme Verlag Stuttgart New York, 1998 ; Plastic Compendium, A. Franck, Vogel Buchverlag, Würzburg, 1996 ). The test methods for flame resistance mimic the conditions in a practical fire under reproducible conditions. Depending on the test method, different physico-chemical data are recorded, such as the ignition and ignition temperature or the composition of the pyrolysate vapors.

In order to meet the requirements for the FST properties (Flammability, Smoke, Toxicity) in the civil aviation cabin sector, prepreg based on phenol-formaldehyde resins (in short: phenolic resins) is usually used as the material for the interior components. Phenolic resins are known for their use Use appropriate fire behavior: they develop less toxic gases in fire than other thermosets and extinguish when removing the flame.

phenolic resins belong to the classic condensation resins, i. H. she polymerize or crosslink with elimination of water. Since that Molded prepreg usually at temperatures above 100 ° C, for example, cured at 160 to 180 ° C. becomes, by the gaseous escaping water the Training a dense, closed surface obstructed. The shell components therefore generally have a very poor surface quality on.

Around the color scheme desired for the cabin area and structure of the component surface to achieve the components are then painted or laminated with foil become. For this, however, a high surface quality necessary. This is usually done by puttying and achieved subsequent grinding of the component, this If necessary, process steps must be repeated. This requires a very high amount of time and effort and is thereby also associated with high costs.

Around To save these steps, it is desirable to use an in-mold coating. Inmould-Coating is a surface coating, prior to molding and curing the prepreg assembly in the mold is applied or during the molding process formed. The inmould coating should be the surface quality of the raw component so that it without elaborate preparation can be painted or laminated. In addition, must the FST requirements continue to be met.

Known are solvent-based in-mold coating systems, which applied before the insertion of the prepreg on the mold surface become. The use of these systems in the vacuum bag process shows but not the desired results. Due the geometric shape of the mold becomes the solvent in Some areas of the mold are insufficiently removed by the vacuum. This leads to the subsequent curing at elevated temperatures to bubble and crater formation on the surface of the component.

in the Hot pressing processes are solvent-based in-mold coating systems not applicable, because the temperature of the molds far beyond the boiling points of commonly used solvents lies. Due to the high temperature, the solvent evaporates immediately out of the system, so no more uniform Movie is received.

A Another possibility is solvent-free systems as in-mold coating. An example of this are gelcoats, which used for the remuneration of epoxy resin laminates become.

It Object of the present invention, the surface quality of hardened components made of fiber-plastic composites to improve. In particular, the invention is the surface quality of Improve components made from prepreg.

These Task is solved by the proposal, a resin matrix for producing a polymer film for surface coating of Fiber-plastic composite materials, wherein (a) the Resin matrix is prepared using at least one di- or polyfunctional aromatic organic cyanate and at least a di- or polyfunctional aromatic alcohol in proportions, a molar ratio of OCN groups to OH groups in the starting materials of the resin matrix between 99: 1 and 60:40 ensure (b) at least one additional resin matrix Substance is added, (c) the resulting mixture in the form of a layer is brought and (d) the resin matrix in the Layer is crosslinked so that they have a degree of crosslinking below of their gel point.

there are preferred proportions of cyanate and alcohol component used, which has a molar ratio of the OCN groups to OH groups in the starting materials of the resin matrix between 95: 5 and 70:30, more preferably between 93: 7 and 75:25 and most preferably between 91: 9 and 80:20.

The polymer films produced according to the invention using the above-mentioned resin matrix have a degree of crosslinking below their gel point. This allows processing or curing in the range between about 100 ° C and 200 ° C. By using the in the not yet published patent application DE 10 2006 041 037.8 In addition, the polymer films have a good storage stability and a low brittleness. The materials obtained by curing of the polymer films according to the invention show a high flame resistance, characterized in that in case of fire, the heat release rates are low, the flue gas density is low and the combustion gases formed a clotting have toxicity.

The Finding suitable cyanate resin matrices for use in the present invention Invention was difficult. Because especially flame-resistant cyanate resins on the basis of phenolic novolacs such. B. PT resins from Lonza have very high after complete curing Glass transition temperatures. To a complete To achieve sales of cyanate groups, it is therefore necessary apply high curing temperatures. It is possible, to harden at low temperatures, because the reaction can for example, by using conventional catalysts such as As metal acetylacetonate complexes can be accelerated. Indeed By using such catalysts, the maximum glass transition temperature is reached not lowered. At curing temperatures far below the curing temperature, which for the maximum Sales of OCN groups is required to freeze the reaction a certain OCN turnover. This turnover is dependent from the curing temperature or their distance from the maximum Glass transition temperature, d. H. from the glass transition temperature at maximum OCN turnover. Below this turnover, however, are Cyanate networks are brittle.

Therefore could have been looking for other catalysts, which at the same time represent network modifiers. You should do that Expand network and at the same time the crosslinking reaction of cyanate resins (trimerization) catalyze. Network expansion would increase the glass transition temperature lowered, so choosing curing temperatures could be, which are below the temperature, which pure Need cyanate resins. Likewise, this could be avoided be that the embrittlement described above by low conversion of OCN groups occurs.

These Search, however, proved problematic. The one in the literature described addition of monofunctional phenols appears, for example not promising. Monofunctional phenols as they are after State of the art can be used in the reaction in the polymer built-in. The underlying mechanism is very complex. It was found that the number of OH groups despite the incorporation of the Phenols remains constant. The reason is the following: for each reacted OH group is released at another location an OH group. The effect of the monofunctional phenol is therefore that of a trifunctional crosslink site a difunctional linkage because the OH group forms a network chain end. This will due to monofunctional phenols, the network density is excessive greatly reduced. They thus set the glass transition temperature well beyond any desirable level are therefore not suitable for the purposes of the present Invention.

Furthermore one finds in the resin matrix an undesirably high sol content. Another disadvantage is that components with relative remain high volatility in the resin matrix, which can outgas later. This in turn should be avoided as described above, the result is an insufficient surface quality the coating of the invention, for example by blistering on or at the surface. In addition, the starting components are volatile, causing problems in processing and handling can.

by virtue of the presence of hydroxy groups in the resin matrix was also to expect that the crosslinking reaction to the polymer film at least over longer periods as they occur during storage can not, as needed, before reaching the gel point comes to a standstill, but runs to a degree of crosslinking, which is far above the gel point. In this case is polymer film no longer homogeneously meltable and thus no longer in the sense of Invention processable. However, good storage stability is absolutely necessary, since the polymer films, which according to the invention under Use of the resin matrices can be made, often over have to be stored for a longer period, before transferring to the final curing stage become.

The Choice of to be used as the starting component for the resin matrix multifunctional cyanates is not critical.

worin R¹ bis R⁴ unabhängig von einander Wasserstoff, ein geradkettiges oder verzweigtes C₁-C₁₀-Alkyl, C₃-C₈-Cycloalkyl, C₁-C₁₀-Alkoxy, Halogen, Phenyl oder Phenoxy ist, wobei die Alkyl- oder Arylgruppen fluoriert oder teilfluoriert sein können,
aus den aromatischen Cyanaten der Formel II

worin R⁵ bis R⁶ wie R¹ bis R⁴ sind und z eine chemische Bindung, SO₂, CF₂, CH₂, CHF, CH(CH₃), Isopropylen, Hexafluoroisopropylen, C₁-C₁₀-Alkylen, O, NR⁹, N=N, CH=CH, COO, CH=N, CH=N-N=CH, Alkylenoxyalkylen mit C₁-C₈-Alkylen, S, Si(CH₃)₂ oder ein Rest mit der Formel IIa, IIb oder IIc

oder aus den aromatischen Cyanaten der Formel III

worin R⁹ Wasserstoff oder C₁-C₁₀-Alkyl ist und n einen Wert von 0 bis 20 darstellt. Die genannten Cyanate können als Monomere oder als vorvernetzte Polymere, allein oder in Mischungen untereinander oder im Gemisch mit weiteren monofunktionellen oder polyfunktionellen Cyanaten eingesetzt werden.In principle, any at least bifunctional aromatic cyanate body can be used. For the preparation of the resin matrix, preference is given to using one or more difunctional or polyfunctional aromatic organic cyanates which are selected from the aromatic cyanates of the formula I.

in which R ¹ to R ⁴ independently of one another are hydrogen, a straight-chain or branched C ₁ -C ₁₀ -alkyl, C ₃ -C ₈ -cycloalkyl, C ₁ -C ₁₀ -alkoxy, halogen, phenyl or phenoxy, where the alkyl or aryl groups may be fluorinated or partially fluorinated,
from the aromatic cyanates of the formula II

in which R ⁵ to R ^{6 are} as R ¹ to R ⁴ and z is a chemical bond, SO ₂ , CF ₂ , CH ₂ , CHF, CH (CH ₃ ), isopropylene, hexafluoroisopropylene, C ₁ -C ₁₀ -alkylene, O, NR ⁹ , N = N, CH = CH, COO, CH = N, CH = NN = CH, Alkylenoxyalkylen with C ₁ -C ₈ alkylene, S, Si (CH ₃ ) ₂ or a radical having the formula IIa, IIb or IIc

or from the aromatic cyanates of formula III

wherein R ^{9 is} hydrogen or C ₁ -C ₁₀ alkyl and n represents a value of 0 to 20. The said cyanates can be used as monomers or as precrosslinked polymers, alone or in mixtures with one another or in a mixture with further monofunctional or polyfunctional cyanates.

worin n gleich 1, 2 oder 3 ist, R⁹ ein Wasserstoff ist und die Methylengruppe jeweils in ortho-Position zur Cyanatgruppe steht.One or more di- or polyfunctional aromatic organic cyanates which are selected from novolak cyanates, bisphenol A dicyanate derivatives, 4,4'-ethylidenediphenyl dicyanates or compounds of the formula III are particularly preferably used for the preparation of the resin matrix

wherein n is 1, 2 or 3, R ^{9 is} a hydrogen and the methylene group is in each ortho position to the cyanate group.

worin R¹ bis R⁴ unabhängig von einander Wasserstoff, ein geradkettiges oder verzweigtes C₁-C₁₀-Alkyl, C₃-C₈-Cycloalkyl, C₁-C₁₀-Alkoxy, Halogen, Phenyl oder Phenoxy ist, wobei die Alkyl- oder Arylgruppen fluoriert oder teilfluoriert sein können,
Verbindungen der Formel V

worin R⁵ bis R⁶ wie R¹ bis R⁴ sind und z eine chemische Bindung, SO₂, CF₂, CH₂, CHF, CH(CH₃), Isopropylen, Hexafluoroisopropylen, C₁-C₁₀-Alkylen, O, NR⁹, N=N, CH=CH, COO, CH=N, CH=N-N=CH, Alkylenoxyalkylen mit C₁-C₈-Alkylen, S, Si(CH₃)₂ oder ein Rest mit der Formel IIa, IIb oder IIc

oder Verbindungen der Formel VI

worin R⁹ Wasserstoff oder C₁-C₁₀-Alkyl ist und n einen Wert von 0 bis 20 darstellt. Die genannten Alkohole können auch als Monomere oder als vorvernetzte Polymere, allein oder in Mischungen untereinander oder im Gemisch mit weiteren mono-, di- oder polyfunktionellen Alkoholen eingesetzt werden.The difunctional or polyfunctional (multivalent) aromatic alcohols to be used are preferably compounds of the formulas IV

in which R ¹ to R ⁴ independently of one another are hydrogen, a straight-chain or branched C ₁ -C ₁₀ -alkyl, C ₃ -C ₈ -cycloalkyl, C ₁ -C ₁₀ -alkoxy, halogen, phenyl or phenoxy, where the alkyl or aryl groups may be fluorinated or partially fluorinated,
Compounds of the formula V

in which R ⁵ to R ^{6 are} as R ¹ to R ⁴ and z is a chemical bond, SO ₂ , CF ₂ , CH ₂ , CHF, CH (CH ₃ ), isopropylene, hexafluoroisopropylene, C ₁ -C ₁₀ -alkylene, O, NR ⁹ , N = N, CH = CH, COO, CH = N, CH = NN = CH, Alkylenoxyalkylen with C ₁ -C ₈ alkylene, S, Si (CH ₃ ) ₂ or a radical having the formula IIa, IIb or IIc

or compounds of the formula VI

wherein R ^{9 is} hydrogen or C ₁ -C ₁₀ alkyl and n represents a value of 0 to 20. The alcohols mentioned can also be used as monomers or as precrosslinked polymers, alone or in mixtures with one another or in a mixture with other mono-, di- or polyfunctional alcohols.

Prefers are the multivalent aromatic alcohols around di- or polyfunctional phenols. It can but for example also be used condensed aromatics such as naphthol derivatives. Particular preference is given to using aromatic difunctional alcohols, in which the hydroxy group in each case directly to the aromatic ring is bound. Preference is given to bisphenols, for example bisphenol A, 4,4'-ethylidenediphenol and bishydroxyphenylsulfide.

Even though used with the aromatic alcohols as defined above compounds whose catalytic effect is a further reaction of the resin matrix can be expected, was surprisingly Latency reached.

latency in this context means that after annealing the crosslinking reaction of the resin matrix to the polymer film for longer periods, as with storage may stall before reaching the gel point comes. In this case, the polymer film is still homogeneously meltable and thus processable in the sense of the invention

These Latency enables manufacturing, transportation and the Storage of the invention using the resin matrices produced polymer films.

By the use according to the invention of the resin matrix, in which the above-defined cyanate component is as defined above Multivalent phenols are modified, the curing the polymer films of the present invention at moderate temperatures for example in the range of 100 ° C to 200 ° C. possible.

Different remains as in the known modification of cyanates with epoxides get the intrinsic flame resistance. Therefore, the inventively used Resin matrix and the polymer film according to the invention preferably be free from epoxy resin ingredients.

Possibly can the reactivity of the invention used Harzmartix by adding known catalysts such. B. one Metallacetylacetonats be increased.

The Already used according to the invention resin matrix through their network structure (due to the heteroaromatic structure and the high nitrogen content) an intrinsic flame resistance on. It combines a low heat release rate with a low smoke density and a low proportion of toxic Gases in case of fire. To special requirements in particular the requirements to the FST characteristics (Flammability, Smoke, Toxicity) in the cabin area to meet civil aviation, the inventive Polymer films one or more additional flame retardants exhibit. Preference is given to inorganic flame retardants, halogen, nitrogen or boron-containing flame retardants, intumescent flame retardants or their mixtures.

Suitable inorganic flame retardants are, for example, non-combustible inorganic fillers substances such as As oxides, hydroxides, oxide hydrates, mixed oxides, sulfides, sulfates, carbonates, phosphates, fluorides of Mg, Ca, Sr, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Mo, Cd, W, Hg, Al, Ga, In, Si, Ge, Sn, Pb, Sb, Bi, aluminum oxides (hydroxides), magnesium oxide, aluminum trihydroxide, magnesium dihydroxide, metal phosphates, ammonium polyphosphates, borates, zinc borates, sodium tetraborate decahydrate , Boric acid, antimony trioxide, antimony pentoxide, red phosphorus, natural or synthetic silicas such. Example, kieselguhr, silica, quartz, cristobalite, silicates, talc, kaolin, mica, asbestos, pumice, perlite, feldspar, mullite, wollastonite, vermiculite, basalt, slate, glass, lava or fused with quartz al-silicates, synthetic silicas such z. As fumed silica, precipitated silica, silicas, silica gels, fused silica, phyllosilicates, bentonites, sulfates of the metals of the 2nd main group such. As calcium sulfate, magnesium sulfate, barium sulfate, synthetic and natural carbonates such. As calcium carbonate, chalk, calcite or dolomite, silicon carbide, rock wool, graphite, glass beads, glass bubbles, glass fibers, fiber fillers such. Asbestos, inorganic pigments or colorants.

suitable halogen-containing flame retardants are, for example, decabromodiphenyl oxide, ethane-1,2-bis (pentabromophenol), Ethylene-bis-tetrabromophthalimide, brominated polystyrene, tribromodiphenyl ether, Tetrabromodiphenyl ether, pentabromodiphenyl ether, hexabromodiphenyl ether, Heptabromodiphenyl ether, octabromodiphenyl ether, nonabromodiphenyl ether, Decabromodiphenyl ether, tetrabromobisphenol A and its derivatives, polybrominated biphenyls such. Decabrombyphenyl, hexabromocyclododecane, Tetrabromophthalic anhydride (TBPA), TBPA diester / ether Ethylenebis (tetrabromophthalimide) (EBTBP), salts of tetrabromophthalates, Dibromoethyl dibromo cyclohexane, ethylene bis (dibromo norbornane dicarboximide), Dibromoneopentyl glycol (DBNPG), tribromoneopentyl alcohol (TBNPA), Vinyl bromide (VBr), 2,4,6-tribromophenol (TBP); To (tribromophenoxy'ethane) ethane (HBPE); Tribromophenyl allyl ether (TBP-AE), poly (dibromophenylene oxide) (PDBPO), pentabromoethylbenzene (5BEB), tetradecabromodiphenoxybenzene (TDBDPB), poly (pentabromobenzyl acrylate) (PBB-PA) and polydibromostyrene (PDBS).

suitable nitrogen-containing flame retardants are, for example, melamine or melamine salts of boric acid, phosphoric acid or other inorganic acids.

suitable Phosphorus-containing flame retardants are, for example, phosphoric acid esters, Ammonium polyphosphate, triphenyl phosphate, tricresyl phosphate, resorcinol bis (diphenyl phosphate), (2 - ((hydroxymethyl) carbamyl) ethyl) phosphonic acid dimethyl ester, Tetraphenylresorcinol bis (diphenyl phosphate) or organic phosphinates.

suitable boron-containing flame retardants are, for example, boric acid, Borax, borates, zinc borate, barium metaborate, calcium metaborate, sodium tetrafluoroborate or potassium tetrafluoroborate.

suitable intumescent flame retardants are, for example, pure melamine, Melamine monophosphate, melamine polyphosphate, melamine cyanurate, melamine pyrophosphate, Melam (1,3,5-triazine-2,4,6-triamine-n- (4,6-diamino-1,3,5-triazine-2-yl), Melem (-2,5,8-triamino 1,3,4,6,7,9,9b-heptaazaphenals), [CAS No. 1502-47-2], Melon (poly [8-amino-1,3,4,6,7,9,9b-Heptaazaphenalen-2,5-diyl) imino] or expandable graphite.

Especially preferred flame retardants are, for example, oxides, hydroxides, Oxide hydrates and borates of Al, Mg, Ti, Si, Sb, Fe and Zn, glass spheres or glass bubbles, tetrabromobisphenol A, tetradecabromodiphenoxybenzene, brominated polystyrene, polydibromostyrene (PDBS), decabromodiphenyl ether, and its derivatives, polybrominated biphenyls and 2,4,6-tribromophenol and mixtures of two or more of the aforementioned flame retardants.

In a preferred embodiment of the invention the resin matrix one or more further substances for adjusting the Viscosity and rheological properties added. The The resin matrix used according to the invention alone can have a viscosity which for further processing too small for the polymer film. So can suitable substances used, which is the viscosity of the resin matrix or the mixture which according to the invention for Setting the polymer film is used, adjust. Suitable substances For example, silicon dioxide, ceramic materials, organic modified silicates. The substances can be used individually or as Mixture be used.

In a further preferred embodiment of the present invention, further additives are used which influence the properties of the invention. A person skilled in the art is familiar with the additives customarily used for the production of paints and coating materials (cf. "Paint Additives"; Bieleman, Johan; Wiley-VCH-Verlag GmbH, Weinheim, 1998 ). Suitable additives are, for example, surfaces modifying agents, in particular surface tension lowering agents such. B. fluorocarbon modified polymers.

Around a uniform and closed surface on the component coated according to the invention it is particularly preferred if the inventively prepared Polymer film free of plastic, glass or carbon fibers, in particular of tissues and is located.

In a particularly preferred embodiment of the invention are the additional substances with a share of 0% up to 85%, preferably 5% to 75%, particularly preferably 10% to 70% used on the mass of the annealed polymer film.

In a preferred embodiment of the invention to prepare the resin matrix, the cyanate component and the alcohol component in appropriate quantities usually separated or together in one dissolved appropriate solvent. Suitable quantities For the purposes of the present invention, such amounts of cyanate and alcohol components that achieve the above mentioned Ensure molar ratios of OCN groups to OH groups. Suitable solvents for the cyanate and alcohol components are known to the skilled person; commonly used solvents are z. As methyl ethyl ketone or acetone. The prepared separately Solutions are then mixed.

In In another embodiment of the invention, the cyanate component also solvent-free at mild temperatures (for example in the range between 40 ° C and 80 ° C) melted become. The alcohol component is used to achieve the required Mole ratio added appropriate amount.

Possibly For example, a catalyst may be added to accelerate crosslinking For example, a metal acetylacetonate complex.

to according to the invention preparation of the polymer film one or more further substances are added to the resin matrix. These can be one of the solutions or the only one or the combined solution of the cyanate and alcohol component be added at any time. Unless in the absence of solvents is used, the other substances the solvent-free mixture or one of the starting components therefor added. When adding fillers takes place in the Usually a dispersion with the usual auxiliaries.

Preferably In particular, the fillers of the cyanate component added before it is combined with the alcohol component, because by stirring in the high-viscosity mixture heat arises, which greatly increases the reactivity and in the worst case for complete curing the entire mixture can lead. Then the alcohol component added.

The Mixture is then placed in the form of a layer for example, by a uniform distribution of the mixture on a substrate of which it is after crosslinking can be removed again to the polymer film. The skilled person is the usual Method for applying a layer known, for example Doctoring, rolling, spraying, pouring, diving, pulling, Apply with brushes, brush or spin.

Especially it is preferred if the mixture is applied to a substrate which is used as a substrate and protection for the polymer film is used. The substrate is after applying the Polymer film on prepreg and before curing of the prepreg removed again from the polymer film.

When Carrier material are, for example, papers or Plastic films, which differ from the invention Remove polymer film. For this it is favorable To use films or papers made of materials which faces a small surface tension Show water, so are water-repellent, or which with such Materials are coated. The basic material for plastic films is preferably a thermoplastic z. B. a polypropylene. As a coating For example, a one- or two-sided silicone coating is suitable.

The mixture according to the invention is preferably applied to the substrate or the substrate in a layer thickness which ensures that the polymer film produced according to the invention has a thickness of 1 μm to 500 μm, preferably 1 μm to 200 μm. It is particularly preferred when the mixture is applied in a layer thickness, which ensures that the polymer film has a thickness of 1 micron to 150 μm, more preferably 1 μm to 100 μm, most preferably 1 μm to 70 μm.

Subsequently is the applied as a layer mixture at a temperature between Annealed at 40 ° C and 160 ° C. By the annealing becomes the resin matrix is prepolymerized, i. H. networked. The temperature is to be chosen so that any existing Solvent is removed, but the gel point of the resin matrix is not achieved. When a thermoplastic film as a carrier substrate It is also important to note that the film does not soften.

The Conditions of tempering such. B. determine temperature and duration the degree of prepolymerization or crosslinking. This will be after selected the respective requirement, but as already be noted that he is aware of the achievement of the Gelpunkts lies, so that a renewed melting and thus a later shaping is possible. Preferably takes place annealing between 40 ° C and 160 ° C, preferably between 50 ° C and 130 ° C, more preferably between 60 ° C and 100 ° C.

Possibly may be the mixture which is the invention Preparation of the polymer film is used without predrying be stored in bulk form before being formed as a layer. Regardless of the shape it will be during storage preferably kept refrigerated, with temperatures usually at -40 ° C to 0 ° C, preferably at -26 ° C, lie.

About that In addition, the polymer film produced according to the invention have a slight stickiness so that when placed on prepreg, a shell component or a mold inner surface adheres. The stickiness on the one hand must be enough to one Prevent slipping. On the other hand, it has to be low enough to the polymer film of the invention of the surface of the prepreg, the component or the mold remove without damaging or destroying it. The tack may optionally without further difficulties be adjusted with the means known in the art.

Of the Polymer film prepared according to the invention the method according to the invention for surface coating of fiber-plastic composites, which are using Prepreg are used, wherein the polymer film before the molding and curing of the composite structure on the resin side a prepreg surface is applied, optionally the carrier substrate is removed and that around the polymer film supplemented composite structure then an increased Temperature is exposed to curing.

Of the Polymer film of the present invention is used at temperatures of 100 to 200 ° C, preferably from 130 ° C to 190 ° C, more preferably from 150 ° C to 170 ° C, cured (corresponds to the curing temperature).

components made of fiber-plastic composites are commonly used from prepreg in the vacuum bag, autoclave or hot pressing process produced. The inventively produced Polymer film can be used as in-mold coating in this process become. The polymer film, for example, only shortly before the curing be applied to the prepreg structure or even during the production of the prepreg the prepreg itself applied and optionally connected to it become.

Of the Polymer film of the present invention, for example, in a one-step process can be used, in which the inventive Polymer film applied to the surface of a prepreg construction This structure is fitted in a mold and after curing is taken out of shape.

Of the Polymer film of the present invention may, for example, also be used in a two-stage process, in which the Prepreg construction first cured in the mold is taken out of the mold after curing and then the polymer film is applied to the component that is bonded to the polymer film occupied component is cured again in the mold and the coated component after curing from the mold is taken.

There the polymer film according to the invention is outgassing easily volatile components from the prepreg structure prevents the formation of a very dense and closed film, it may be preferred as a coating of phenolic resin-containing prepreg be used in a one-step process.

In a particular embodiment of the present invention, the polymer film is applied to the surface of a prepreg assembly, the prepreg assembly is placed in a preheated mold, the mold Pressed with pressure and hardened the prepreg structure. Preference is given to a sandwich construction with a honeycomb core between phenolic resin-containing prepreg layers and a curing time of 2 to 20 minutes, more preferably 5 to 15 minutes, at temperatures between 100 ° C and 200 ° C, particularly preferably at 140 ° C to 170 ° C, completely particularly preferably at 160 ° C, and at a pressure of 1.5 to 8 bar, more preferably at 4 bar. The pressure can be selected, for example, so that the honeycomb core is easily deformed (so-called crushed-core method).

The FST properties of one according to the present Invention coated fiber-plastic composite component for example, with those for aviation relevant standard test methods for flame resistance be like International Standard ISO TC92 / SC1 or Airbus Directive ABD0031.

in the The invention will be more closely understood by way of examples explained.

Example 1: Preparation of the polymer film

• *nach Bedarf (n. B.)

The cyanate component is degassed, melted at suitable mild temperatures and dissolved in acetone as needed. The alcohol component is dissolved separately in acetone. Fillers and flame retardants (see Table 1) are added to the cyanate component. Subsequently, the components are combined and mixed with stirring. Optionally, the viscosity of the mixture is adjusted by adding further fillers or additives. The resulting mixtures are each knife-coated on one side of a double-sided siliconized film. Subsequently, the so-coated film is annealed in the oven at temperatures between 60 ° C and 100 ° C over a period of 1 minute to 40 minutes. Depending on the resin matrix used, the conditions of tempering are selected such that the degree of prepolymerization or precrosslinking of the polymer film is below its gel point. Table 1: Compositions of mixtures for the preparation of the polymer film example 1a 1b 1c 1d 1e 1f 1g ingredients Quantity in mass proportions cyanate Oligo (3-methylene-1,5-phenylene) diisocyanate 65 65 65 65 65 65 65 4,4'-Ethylidendiphenyldicyanat 25 25 25 25 25 25 25 alcohol component Bishydroxyphenylsulfid - - - - - - 10 Bisphenol A 10 10 10 10 10 10 - solvent acetone - - - - - - n. B. * other substances fluorocarbon-modified polymer 2 2 2 2 2 2 2 organic phosphinate 50 25 30 30 - 30 organophilic bentonite 10 10 - - - - Hollow glass spheres - - - - - 5 fumed silica - - 4 4 4 2 4 pigment 5 - - 5 5 5 5

• * as needed (n. B.)

Example 2: Preparation of a Coated Interior component for aviation

One Nomex honeycomb core is saturated on both sides with phenolic resin Prepregs occupied. A polymer film of Example 1 is used with the Resin side placed on the surfaces of this structure. Subsequently, the carrier film is removed, the Structure introduced into a heated to 160 ° C mold, the Form closed. It is applied a pressure of about 4 bar and The component is compressed at 160 ° C for about 15 minutes. While Press time, the structure forms into the form and becomes in cured of this form. Thereafter, the finished component taken from the mold.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102006041037 [0022]

Cited non-patent literature

• - Römpp-Lexikon Paints and printing inks; Ed. U. Zorll, Thieme Verlag Stuttgart New York, 1998 [0011]
• - Plastic Compendium, A. Franck, Vogel Buchverlag, Würzburg, 1996 [0011]
• - "paint additives"; Bieleman, Johan; Wiley-VCH-Verlag GmbH, Weinheim, 1998 [0048]

Claims (21)

Use of a resin matrix for the production of a Polymer film for surface coating of fiber-plastic composites, in which (a) the resin matrix is prepared using at least a di- or polyfunctional aromatic organic cyanate and at least one di- or polyfunctional aromatic alcohol in proportions representing a molar ratio of the OCN groups to OH groups in the starting materials of the resin matrix between 99: 1 and 60:40 ensure (b) the resin matrix at least another substance is added, (c) the resulting Mixture is brought into the form of a layer, (d) the resin matrix in the layer is crosslinked so that they have a degree of crosslinking below its gel point. Use of the resin matrix for producing a polymer film according to claim 1, wherein a resin matrix prepared by using one or more di- or polyfunctional aromatic organic cyanates selected from the aromatic cyanates of the formula I is used

in which R ¹ to R ⁴ independently of one another are hydrogen, a straight-chain or branched C ₁ -C ₁₀ -alkyl, C ₃ -C ₈ -cycloalkyl, C ₁ -C ₁₀ -alkoxy, halogen, phenyl or phenoxy, where the alkyl or aryl groups may be fluorinated or partially fluorinated, from the aromatic cyanates of the formula II

in which R ⁵ to R ^{6 are} as R ¹ to R ⁴ and z is a chemical bond, SO ₂ , CF ₂ , CH ₂ , CHF, CH (CH ₃ ), isopropylene, hexafluoroisopropylene, C ₁ -C ₁₀ -alkylene, O, NR ⁹ , N = N, CH = CH, COO, CH = N, CH = NN = CH, Alkylenoxyalkylen with C ₁ -C ₈ alkylene, S, Si (CH ₃ ) ₂ or a radical having the formula IIa, IIb or IIc

or from the aromatic cyanates of formula III

wherein R ^{9 is} hydrogen or C ₁ -C ₁₀ alkyl and n represents a value of 0 to 20. Use of the resin matrix for producing a polymer film according to claim 2, wherein a resin matrix prepared by using at least one di- or polyfunctional organic cyanate selected from novolak cyanates, bisphenol A dicyanate derivatives, 4,4'-ethylidene diphenyl dicyanates or compounds with the formula III

wherein n is 1, 2 or 3, R ^{9 is} a hydrogen and the methylene group is in each ortho position to the cyanate group. Use of the resin matrix for producing polymer film according to any one of claims 1 to 3, wherein a resin matrix is used which is prepared using one or more di- or polyfunctional aromatic alcohols selected from compounds of formula IV

in which R ¹ to R ⁴ independently of one another are hydrogen, a straight-chain or branched C ₁ -C ₁₀ -alkyl, C ₃ -C ₈ -cycloalkyl, C ₁ -C ₁₀ -alkoxy, halogen, phenyl or phenoxy, where the alkyl or aryl groups may be fluorinated or partially fluorinated, from compounds of the formula V

in which R ⁵ to R ^{6 are} as R ¹ to R ⁴ and z is a chemical bond, SO ₂ , CF ₂ , CH ₂ , CHF, CH (CH ₃ ), isopropylene, hexafluoroisopropylene, C ₁ -C ₁₀ -alkylene, O, NR ⁹ , N = N, CH = CH, COO, CH = N, CH = NN = CH, Alkylenoxyalkylen with C ₁ -C ₈ alkylene, S, Si (CH ₃ ) ₂ or a radical having the formula IIa, IIb or IIc

or from compounds of the formula VI

wherein R ^{9 is} hydrogen or C ₁ -C ₁₀ alkyl and n represents a value of 0 to 20. Use of the resin matrix for the production of polymer film according to claim 4, wherein a resin matrix is used which is prepared is using one or more difunctional aromatic Alcohols selected from bisphenols, 4,4'-ethylidenediphenol or bishydroxyphenylsulfide. Use of the resin matrix to produce a polymer film according to one of claims 1 to 5, characterized that at least one other substance is used, which is selected is made of silicon dioxide, ceramic materials, organically modified Silicates or mixtures thereof. Use of the resin matrix to produce a polymer film according to one of claims 1 to 6, characterized that at least one other substance is used, which is a Flame retardant is. Use of the resin matrix to produce a polymer film according to claim 7, characterized in that at least one flame retardant is used, which is selected from inorganic flame retardants, halogen, nitrogen or boron-containing flame retardants, intumescent Flame retardants or mixtures thereof. Use of the resin matrix to produce a polymer film according to claim 8, characterized in that at least one flame retardant is used, which is selected from oxides, hydroxides, Oxide hydrates, borates of Al, Mg, Ti, Si, Sb, Fe or Zn, glass spheres, Hollow glass spheres, tetrabromobisphenol A, tetradecabromodiphenoxybenzene, brominated polystyrene, polydibromostyrene (PDBS), decabromodiphenyl ether or its derivatives, polybrominated biphenyls, 2,4,6-tribromophenol or mixtures thereof. Use of the resin matrix for the production of a Polymer film according to one of claims 1 to 9, characterized characterized in that at least one further substance is used, which is selected from surface-modifying, preferably surface tension lowering agents. Use of the resin matrix for the production of a Polymer film according to one of claims 1 to 10, characterized characterized in that one or more further substances with a proportion from 0% to 85%, preferably 5% to 75%, most preferably 10% to 70%, based on the mass of the annealed polymer film used become. Use of the resin matrix for the production of a Polymer film according to one of claims 1 to 11, characterized characterized in that the mixture resulting from step b) a substrate is applied. Use of the resin matrix for the production of a Polymer film according to claim 12, characterized in that as Substrate a film of a one- or two-sided siliconized Plastic or a one- or two-sided siliconized paper is used. Use of the resin matrix for the production of a Polymer film according to one of Claims 1 to 13, characterized that the mixture resulting from step b) on the ground or the substrate is applied in a layer thickness which ensures that the polymer film has a thickness of 1 micron to 500 .mu.m, preferably 1 .mu.m to 200 .mu.m having. Use of the resin matrix for the production of a Polymer film according to claim 14, characterized in that the Mixture is applied in a layer thickness, which ensures the polymer film has a thickness of 1 μm to 150 μm, preferably 1 .mu.m to 100 .mu.m, more preferably 1 μm to 70 μm. Use of the resin matrix for the production of a Polymer film according to one of claims 1 to 15, characterized characterized in that the crosslinking by annealing at a temperature between 40 ° C and 160 ° C is achieved. Use of the resin matrix for the production of a Polymer film according to one of claims 1 to 16, characterized characterized in that the polymer film is free of plastic, glass or carbon fibers. Process for surface coating of Fiber-plastic composites, which are made using prepregs be prepared, characterized in that (a) the polymer film according to any one of claims 1 to 17 before molding and Curing of the composite structure on the resin side on a prepreg surface is applied, (b) added to the polymer film Composite construction then an elevated temperature is exposed to curing. Process for surface coating of Fiber-plastic composite materials according to claim 18, characterized in that that at temperatures of 100 to 200 ° C, preferably from 130 ° C to 190 ° C, more preferably from 150 to 170 ° C, is cured. Process for surface coating of Fiber-plastic composite materials according to claim 18 or 19, characterized characterized in that at a pressure of 1.5 to 8 bar, especially preferably at 4 bar, is cured. Process for surface coating of Fiber-plastic composite materials according to claim 20, characterized in that that cured for 2 to 20 minutes, preferably 15 minutes becomes.