EP2820060A1

EP2820060A1 - 2k polyurethane systems with phase separation

Info

Publication number: EP2820060A1
Application number: EP13705802.0A
Authority: EP
Inventors: Andreas Ferencz; Lothar Thiele; Tamara Schmidt; Konrad Becker; Wolfgang LUPP; Dustin ULLMANN; Oliver-Kei Okamoto
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2012-02-28
Filing date: 2013-02-25
Publication date: 2015-01-07
Also published as: JP2015512979A; JP2019035088A; AU2013225178A1; CN104136477A; CN104136477B; US20140371391A1; AU2013225176A1; CN104136476A; KR20140129304A; US10131738B2; MX2014010290A; JP6534260B2; US10093766B2; CN104136476B; CA2863145A1; EP2820061B1; AU2013225178B2; MX365691B; CA2863145C; US20160362516A1

Abstract

The invention relates to a two-component polyurethane composition containing i) 10 to 80 wt.% of at least one polyol with an average molecular weight of 200 g/mol to 3000 g/mol, ii) 5 to 60 wt.% of at least one aromatic polyisocyanate, and iii) 0 to 15 wt.% of an additive. The composition has an NCO:OH ratio of 2:1 to 1:2, and the composition has a viscosity of 20 to 3000 mPas (EN ISO 2555, Brookfield viscometer, 25°C) and displays a phase incompatibility after the mixing process. The functionality of the polyol mixture is greater than 2.3.

Description

"2-component polyurethane system with phase separation"

The invention relates to a 2K PU composition, ie a two-component composition based on a polyol component and an isocyanate component, which is to be introduced with low viscosity into fiber-filled molds. The composition in liquid form shows a phase separation. The composition should have a high glass transition temperature in the crosslinked state.

Fiber-reinforced molded parts should have high mechanical properties. For this purpose, it is necessary that the matrix materials used are stably connected to the fiber materials. All defects have a negative effect on the mechanical properties of the molded parts. It should therefore be as possible no voids, voids, and / or bubbles contained in the corresponding part. Suitable matrix materials based on epoxy binders are known. However, these have various disadvantages, for example, the reactivities of the systems are often too high. This can lead to high exothermicity of the reaction mixture, which can also affect the properties of the polymers. Therefore, other binders based on reactive 2-component polyurethane systems (2K PU systems) have also been developed.

WO2008 / 1 10602 describes a PU adhesive composition which consists of a component containing compounds having acidic H atoms and a polyisocyanate component together with a trimerization catalyst for the isocyanates. It is required in the claims that the two components should be compatible with each other.

WO201 1/067246 describes a resin system containing polyisocyanates, compounds having acidic H atoms reactive to the polyisocyanate, a catalyst and a higher functional acid. The acid must be soluble in the compound with the reactive H groups. WO 2010/023060 describes a mixture of an isocyanate-reactive compound which contains a trimerization catalyst. This is obtained from phthalic acid or trimellitic acid by reaction with polyols, whereby special proportions must be maintained.

EP 1471088 describes polyurethane compositions containing polyols with aromatic amine compounds. These polyols are expressly described as compatibilizing.

WO 2009/150010 describes a composition of polyols with an isocyanate component, wherein the isocyanate component comprises at least 65% of the NCO groups as sterically hindered NCO groups. The composition should be used in fiber materials as matrix resin.

The above-mentioned compositions are frequently used to produce fiber-reinforced molded parts. In this case, appropriate fiber materials are inserted in closed molds, these are then coated with the above-mentioned materials as a matrix resin. This can be assisted by various methods, for example by applying pressure, increasing the temperature or applying vacuum. Since imperfections significantly affect the application properties, it is useful when low viscosity materials are used.

It has been shown that the viscosity of the PU systems can be set very low at the beginning of the reaction. In this case, the binders should flow around all fiber components, since even small remaining bubbles on the fibers, for example at intersection points, weaken the molded part. However, since the corresponding moldings can also have larger dimensions or complicated shapes, it is necessary that the viscosity remains low even for a sufficient time to fill the mold. Only under these circumstances can it be ensured that as far as possible no defects in the matrix material occur when a high degree of filling of fiber fractions in the component is to be achieved. On the other hand, however, the composition should crosslink as quickly as possible in order to enable rapid removal from mold and to make better use of the molds. The above known compositions have special catalysts. These are to ensure that a crosslinking reaction of the isocyanate / OH groups is delayed. This makes it possible to delay the increase in the viscosity of the compositions. But it also slows down the final networking. Furthermore, it is common that such catalysts are present only in small amounts. These must therefore be contained in an exact amount to be measured, otherwise the properties for industrial production are not sufficiently reproducible.

Another requirement for the corresponding matrix binders is that the mechanical properties remain constant after crosslinking, even to the external conditions. It has been shown that an influencing parameter for the mechanical properties is the glass transition temperature (Tg). This can be influenced by the choice of polyols or the crosslink density, but the viscosity required for processing should not be adversely affected. In particular, the Tg can be influenced by the choice of polyols or the crosslinking density, but the viscosity required for processing should not be adversely affected.

It has been shown in practice that incompatible mixtures are formed when polyols and isocyanates are mixed. This can clearly be seen in the turbidity of the mixtures, which in themselves are clear. However, it is known that such a phase separation leads to inhomogeneous components. Therefore, in the prior art, either special compatibilizers are added or a specific selection of the polyols is to be made.

It is therefore the object to provide a polyurethane binder system which has a low viscosity in the non-crosslinked state and this low viscosity is maintained during a longer processing period. A broad selection of polyols should be possible. These systems can then be processed directly into matrix compositions. The crosslinked matrix should have a high glass transition temperature and good mechanical properties. The object is achieved by a two-component polyurethane composition comprising i) 10 to 80 wt .-% of at least one polyol having a number average molecular weight of 200 g / mol to 3000 g / mol, ii) 5 to 70 wt .-% at least one aromatic polyisocyanate, iii) 0 to 15 wt .-% additives, wherein the composition has an NCO: OH ratio of 2: 1 to 1: 2, the composition has a viscosity of 20 to 3000 mPas (EN ISO 2555, Brookfield Viscometer, 25 ° C) and shows after mixing a phase incompatibility and the functionality of the polyol mixture is greater than 2.3.

Another object of the invention is a two-component polyurethane composition containing i) 10 to 80 wt .-% of at least one liquid polyol having a molecular weight of 200 g / mol to 3000 g / mol, ii) 5 to 70 wt. % of at least one aromatic polyisocyanate and optionally 0 to 15 wt .-% additives, wherein the composition has an NCO: OH ratio of 2: 1 to 1: 2, the composition has a viscosity of 20 to 3000 mPas and after mixing a Phase intolerance shows.

Another object of the invention is the use of such 2K PU compositions for producing fiber-reinforced molded parts.

A further subject matter is processes for producing molded parts from fiber materials and such 2K PU compositions.

The 2K PU composition according to the invention consists of a polyol component and a crosslinker component. The polyol component contains at least one liquid polyol and optionally additives. The crosslinker component contains the isocyanates and optionally those additives which do not react with NCO groups.

The polyol component used can be the customary polyol compounds known to those skilled in the art. In the context of the invention, a multiplicity of polyfunctional alcohols can be used. Preferably, these polyols should have no further reactive with NCO groups functional groups, such as reactive amino groups. The compounds having multiple OH groups may be those bearing terminal OH groups or may be compounds be distributed over the chain distributed side OH groups. The OH groups are those which can react with isocyanates, in particular are primary or secondary OH groups. Suitable polyols are 2 to 10, preferably with 2 to 6 OH groups per molecule. Mixtures of different polyols may be used as far as a corresponding average functionality is obtained. The molecular weight should be from 100 to 3000 g / mol (number-average molecular weight M _N , measured by GPC), preferably from 200 to 1500 g / mol. Examples of suitable polyols are those based on polyethers, polyalkylenes, polyesters or polyurethanes. The polyols are preferably present as a mixture in liquid form at room temperature (25 ° C), in particular, each polyol is individually liquid.

Suitable polyols are, for example, liquid polyester polyols obtained by condensation of di- or tricarboxylic acids, e.g. Adipic acid, sebacic acid and glutaric acid with low molecular weight diols or triols, e.g. Etylenglykol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, 1, 4-butanediol, 1, 6-hexanediol, glycerol or trimethylolpropane, can be prepared. Another group of such polyols to be used are the polyesters based on lactones, such as polycaprolactones. Those skilled in the art are aware of such OH-functional polyesters and they are commercially available. Particularly suitable are two or three terminal OH-containing polyester polyols. These polyester polyols should have a molecular weight of up to 2000 g / mol, preferably in the range of 500 to 1000 g / mol.

However, it is also possible to use polyester polyols of oleochemical origin. Such polyester polyols can be prepared, for example, by complete ring opening of epoxidized triglycerides of an at least partially olefinically unsaturated fatty acid-containing fat mixture with one or more alcohols having 1 to 12 carbon atoms and subsequent partial transesterification of the triglyceride derivatives to alkyl ester polyols having 1 to 12 carbon atoms in the alkyl radical , Examples of such polyols are castor oil or dimer diols. These oleochemical polyols should have hydroxyl numbers of 50 to 400 mg KOH / g, preferably 100 to 300 mg KOH / g, which corresponds to a molecular weight of about 250 to 2000 g / mol. Other suitable polyester poles are polycarbonate polyols. Polycarbonates can be obtained, for example, by the reaction of diols, such as propylene glycol, butanediol-1,4 or hexanediol-1,6, diethylene glycol, triethylene glycol or tetraethylene glycol or mixtures of two or more thereof with diaryl carbonates, for example diphenyl carbonate, or phosgene. Another group of polyols to be used according to the invention are polylactones, for example polyesters based on ε-caprolactone. Also suitable are those polyester polyols which contain one or more urethane groups in the molecular chain.

It is also possible to use aliphatic polyols. These should have a functionality of 2 to 10, in particular from 2 to 6. These may be the known polyols, such as ethylene glycol, propanediol, butanediol-1, 4, pentanediol-1, 5, hexanediol-1, 6, heptanediol- 1, 7, octanediol-1, 8 1, 10-decanediol, 1, 12-dodecanediol, dimer fatty alcohol, glycerol, hexanetriol glycerol, trimethylolpropane, pentaerythritol or neopentyl alcohol. It is also possible to use so-called sugar alcohols. Suitable aliphatic alcohols have a molecular weight of 60 to 400 g / mol. In particular, however, linear alcohols having 2 to 30 carbon atoms are used, which have two to four OH groups.

A particularly suitable group are polyether polyols which are reaction products of low molecular weight, polyfunctional alcohols with alkylene oxides. The alkylene oxides preferably have 2 to 4 C atoms. These may be two- or higher-functional polyols, preference is given to polyols having 2, 3 or 4 OH groups. Examples are ethylene glycol, propanediol, butanediol, hexanediol, octanediol; polyfunctional alcohols, such as glycerol, hexanetriol, trimethylolpropane, pentaerythritol, neopentyl alcohol; Sugar alcohols, such as mannitol, sorbitol, methyl glycosides. Also, corresponding aromatic polyols such as resorcinol, hydroquinone, 1, 2,2- or 1, 1, 2-tris (hydroxyphenyl) ethane can be reacted with the alkylene oxides. Further, in the context of the invention, suitable polyols formed by polymerization of tetrahydrofuran (poly-THF). It is possible to use random and / or block copolymers of ethylene oxide and propylene oxide. Polyether polyols having 2, 3 or 4 OH groups are preferred. The polyether polyols are prepared in a manner known to those skilled in the art and are commercially available. Preference is given to polyoxyethylene or polyoxypropylene diols or triols. The molecular weight of these polyethers can be from about 200 to 3000 g / mol, in particular up to 1000 g / mol.

Polyols containing tertiary amino groups are preferably not included in the composition. These worsen the application properties. The functionality of the polyol mixture should be greater than 2.3, in particular from 2.5 to 4. In one embodiment of the invention, the composition is characterized in that polyols are used as polyols - and / or in particular polyether polyols having an average functionality of more than 2, 5th If the crosslink density is insufficient, the crosslinked matrix binder is not sufficiently mechanically stable.

Polyisocyanates in the isocyanate component polyfunctional isocyanates are suitable. Preferably, the isocyanates contain an average of 2 to 5, preferably 4 NCO groups. Examples of suitable isocyanates are aromatic isocyanates, such as, 5-naphthylene diisocyanate, 2,4- or 4,4'-diphenylmethane diisocyanate (MDI), xylylene diisocyanate (XDI), m- and p-tetramethylxylylene diisocyanate (TMXDI), the isomers of tolylene diisocyanate (TDI), di- and tetraalkyldiphenylmethane diisocyanate, 3,3'-dimethyl-diphenyl-4,4'-diisocyanate (TODI) 1, 3-phenylenediisocyanate, 1, 4-phenylenediisocyanate, 4,4'-dibenzyldiisocyanate; aliphatic isocyanates, such as hydrogenated MDI (H12MDI), 1-methyl-2,4-diisocyanato-cyclohexane, 1,12-diisocyanatododecane, 1,6-diisocyanato-2,2,4-trimethylhexane, 1,6-diisocyanato-2, 4,4-trimethylhexane, 1-isocyanatomethyl-3-isocyanato-1, 5,5-trimethylcyclohexane (IPDI), tetramethoxybutane-1,4-diisocyanate, butane-1,4-diisocyanate, hexane-1,6-diisocyanate (HDI), dimer fatty acid diisocyanate, dicyclohexylmethane diisocyanate, cyclohexane-1, 4-diisocyanate, ethylenediisocyanate or phthalic acid bis-isocyanatoethyl ester.

It is also possible to use fractions of low molecular weight prepolymers, for example reaction products of MDI or TDI with low molecular weight diols, such as, for example, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol or triethylene glycol. These prepolymers can be prepared by reacting an excess of monomeric polyisocyanate in the presence of diols. The molecular weight of the diols is generally below 1000 g / mol. Optionally, the reaction product can be freed by distillation of monomeric isocyanates. In one embodiment, aromatic diisocyanates are preferred according to the invention, in another form it is preferred to use mixtures of aliphatic and aromatic isocyanates. In particular, at least 50 mol% of the NCO groups should be based on MDI and its isomers. In one embodiment, the 2K PU composition is characterized in that the isocyanate groups contain at least 50 mol% of NCO groups of MDI and its isomers. It should be used liquid isocyanates, as far as they show a phase incompatibility with the polyols. According to the invention it is also possible, but not necessary, for the amount of isocyanate groups to be reduced by reaction with carbodiimides and their derivatives, in particular with uretonimines. In one embodiment, the 2K PU composition is characterized in that the composition contains carbodiimides and / or uretonimines from the aromatic isocyanates. The proportion of the reacted NCO groups may be from 3 to 25 mol% of the NCO groups originally present. Preferably, the mixture of polyisocyanates should be flowable at room temperature (25 ° C). In order to obtain stable compositions, this component should not contain ingredients which give reactions which cause an increase in viscosity under storage conditions.

The 2K-PU compositions according to the invention may further comprise auxiliaries, which are preferably mixed completely or partially with the polyol component. By these are meant substances which are usually added in small amounts in order to alter the properties of the composition, e.g. the viscosity, the wetting behavior, the stability, the reaction rate, the blistering, the shelf life or the adhesion, as well as the performance properties to suit the application. Examples of auxiliaries are leveling agents, wetting agents, catalysts, anti-aging agents, dyes, drying agents, resins and / or waxes.

For example, the composition of the invention may additionally contain stabilizers. Stabilizers for the purposes of this invention are to be understood as meaning antioxidants, UV stabilizers or hydrolysis stabilizers. Examples of these are the commercially available sterically hindered phenols and / or thioethers and / or substituted benzotriazoles and / or amines of the "HALS" type (Hindered Amine Light Stabilizer). It is also possible to use catalysts. The catalysts used are the customary organometallic compounds known in polyurethane chemistry, such as, for example, iron, titanium, zirconium, aluminum, lead, bismuth or in particular tin compounds. It is preferably possible for these catalysts to comprise, as a mixture or as a complex in a molar ratio of from 0.25: 1 to 2: 1, polyhydroxy compounds selected from cyclic α-hydroxyketones and / or triphenols having three adjacent OH groups. In particular, 5, 6 or 7-membered ring compounds can be used as cyclic α-hydroxyketones and the triphenols used can be 1-alkyl-substituted 2,3,4- or 3,4,5-OH derivatives. These are substances which act as complexing agents with the abovementioned metal atoms. These complexing agents should have a molecular weight below 500 g / mol or it may also be bound to a carrier. In particular, such substances are suitable as complexing agents, which optionally have a further OH, COOH or ester group. Thus, in the crosslinking reaction of this complexing agent can also react with the reactive composition and firmly bound the matrix.

Another group of catalysts are those based on tertiary amines. For example, linear or cyclic aliphatic amines are suitable, such as methylcyclohexylamine, dimethylbenzylamine, tributylamine, monoethanolamine, triethanolamine, diethylenetriamine, triethylenetetramine, triethylenediamine, guanidine, morpholine, N-methylmorpholine, diazabicyclooctane (DABCO), 1,8-diazabicyclo- 5,4,0) -undecene-7 (DBU) or diazabycyclonones (DBN). The catalyst may be used in an amount of 0.01 to about 5% by weight based on the total weight of the composition.

An embodiment of the 2K PU composition is characterized in that the catalyst comprises Sn compounds, in particular Sn catalysts with polyhydroxy compounds as complexing agents or tertiary amines, selected from cyclic α-hydroxyketones or 1-alkyl-2,3,4-triphenols ,

It is also possible that small amounts of plasticizer, color pastes or a molecular sieve are included. As a desiccant and liquid compounds can be used which absorb moisture during storage. The quantity but it should be below 10 wt .-% (based on the 2K composition) amount. Preferably, no pigments, molecular sieves, fillers and / or plasticizers are included. The composition according to the invention should preferably contain no organic solvents. The solvents to be understood here are liquid substances having a boiling point below 200 ° C. Substantially non-volatile compounds used to disperse or dissolve additives are not considered solvents in this regard.

Furthermore, resins may optionally be included. These may be natural or synthetic resins. A particular embodiment employs OH-group-containing resins, in particular resins having a plurality of OH groups. These can react with the isocyanates. In a preferred embodiment, the amount may be up to 15% by weight.

The additives are added to the components so that the storage stability is given. In particular, no additives should be added, for example mono- or polyfunctional carboxylic acids, which promote the formation of gas bubbles such as CO2 in the adhesive.

A preferred embodiment of the composition contains 30 to 70 wt .-% polyols having a functionality above 2.5, in particular polyether polyols and / or polyester polyols, 70 to 30 wt .-% polyisocyanates, in particular with at least 50 mol% of all isocyanate groups of MDI and its isomers, 0.1 to 5 wt .-% of additives selected from stabilizers and catalysts, wherein the sum of the ingredients should give 100%. In particular, the mixture should be free of reactive amine-containing constituents, for example polyols.

In this case, a mixture according to the invention after mixing at mixing temperature must show an incompatibility.

As incompatible in the sense of the invention is to be understood that the components are miscible with each other, but they form two phases. This can be determined in particular visually. The individual components are transparent, after mixing and optionally degassing forms a turbid phase. A simple test mixes both Components, optionally without pigments, at 25 ° C. Then the samples rest and are visually assessed. Is the solution of the components up to 2 min. cloudy, there is a phase separation.

In order to enable a use according to the invention, a 2K PU composition according to the invention has a viscosity in mixed form of 20 to 3000 mPas (measured with Brookfield RTV, DIN ISO 2555), measured at a temperature between 20 and 60 ° C. In particular, the viscosity should be from 100 to 1000 mPas measured at 20 to 40 ° C. In this case, the 2K PU composition according to the invention can be applied at these temperatures. The viscosity should be determined immediately after mixing, for example up to 2 min. after mixing, by the onset of crosslinking reaction, it increases slowly.

The 2K PU composition according to the invention has a good processing time. This should be over 10 min. be. The term "processing time" is understood to mean the time after which the viscosity of a mixture has risen to more than 300% of the initial value at 25 ° C., but at least to over 3000 mPas. The processing time can be influenced by the choice of isocyanates and catalysts.

The 2K PU compositions form a two-phase system after mixing. This can be seen by the incompatibility. At about 25 ° C., multiphase systems dispersed in one another are formed, as can be ascertained by turbidity of the mixture produced. The mixtures according to the invention should be used in the phase separation state.

By selecting the constituents, the composition according to the invention should have a glass transition temperature (Tg) of more than 60 ° C. (measured by DSC, DIN 1 1357), in another embodiment in particular from 100 to 130 ° C. The high Tg is necessary to obtain the required mechanical stability even of the cured composite system. The inventive selection of the polyol and the isocyanate component a high mechanical stability of the composition is obtained. The structural stability of the matrix material can be measured, for example, via the modulus of elasticity. The composition according to the invention At temperatures between -10 ° C and + 70 ° C, the modulus of elasticity is greater than 1000 MPa (analogous to DIN EN ISO 527).

The 2K PU compositions according to the invention are suitable as matrix resin for fiber-reinforced molded parts (composites). These can be used in various application methods, for example in the RTM method or in the infusion method.

The invention also provides a process for the production of composite materials, in which the two-component PU compositions according to the invention are used. In this case, the compositions according to the invention are applied by being introduced into a mold.

As components of composite materials known high-strength fiber materials are suitable. These can be made of glass fibers, for example; synthetic fibers such as polyester fibers, polyethylene fibers, polypropylene fibers, polyamide fibers, polyimide fibers or aramid fibers; Carbon fibers; boron fibers; oxide or non-oxide ceramic fibers such as alumina / silica fibers, silicon carbide fibers; Metal fibers, for example of steel or aluminum; or consist of natural fibers such as flax, hemp or jute. These fibers may be incorporated in the form of mats, fabrics, knits, mats, fleeces or rovings. Two or more of these fiber materials may also be used as a mixture. Short cut fibers can be selected, but preferably synthetic long fibers are used, in particular fabrics and scrims. Such high strength fibers, scrims, fabrics and rovings are known to those skilled in the art.

The fibers are inserted in the molds in a predetermined orientation. The amount of fiber materials can be very high, in particular fiber contents of over 60% (volume%) are used based on the molding. It may optionally also be inserted further inserts. Thereafter, the premixed composition of the invention is introduced.

One embodiment of the method according to the invention is a method for producing fiber composite materials, wherein an outer shape with fiber materials is provided and in this form a liquid 2K-PU composition is introduced under pressure, wherein this composition is introduced in the state of phase incompatibility, characterized in that and the proportion of the fiber materials is more than 60 vol.%.

In the process according to the invention, the 2K mixture is used immediately after production. It is essentially about visually turbid mixtures, which is regarded as a sign of phase incompatibility. Since the mixed composition reacts, it is convenient to mix only the amount of components that can be processed immediately thereafter. It is also possible to continuously mix and fill the molds. Since the incompatible phases are in the form of a fine dispersion, the compositions are easily processed with the usual devices, such as pumps, nozzles or hoses. Irrespective of a theory, it can be assumed that the incompatibility causes a reduction in the reaction rate.

The method according to the invention comprises two embodiments. The inflow can be carried out by injecting under pressure (resin transfer molding or RTM method), possibly also with support by vacuum, in a short time. Here, compositions are preferred which have a shorter processing time, but then show a rapid response. Another embodiment fills the mold by applying vacuum (infusion method). In this embodiment, a long open time is advantageous. The viscosity of the composition suitable according to the invention must be low. It may also increase only slightly under the process conditions of filling the mold. According to the invention, the mixture of the composition immediately after mixing should be between 20 and 3000 mPas (EN ISO 2555, Brookfield viscometer, 25 ° C.), preferably below 1000 mPas. It is important to ensure that the flow rate is selected so that air or gases can escape between the fiber materials.

In the embodiment for infusion methods, a long processing time is particularly important. Therefore, in this embodiment, in particular compositions are used which do not contain catalysts. The flow of the fiber materials, a displacement of the air bubbles and a filling of the mold can over a longer Period to be carried out. Due to the slow progress of the reaction, the fiber materials can be completely embedded in the matrix material.

In the embodiment as an RTM method, filling of the mold must take place in a short time. The cloudy reaction mixture is brought under pressure into the mold. Due to the low initial viscosity, a fast embedding of the fibers can be ensured. In this embodiment, the compositions also preferably contain catalysts. These lead after a short time to an acceleration of the reaction, so that a rapid hardening takes place. This can also be supported by an increased temperature. In this case, then a short residence time in the form is possible.

After filling the mold, the composition begins to harden. This can be done without additional heat. The heat of reaction generated by the crosslinking reaction does not lead to a local overheating of the substrates. In order to accelerate the crosslinking reaction, it is possible to heat the filled mold. It can be heated to temperatures up to 120 ° C. In this case, a faster crosslinking of the matrix material is achieved. Thus, the mold can be removed earlier from the molding and is then available for further work steps.

Another object of the invention is also a fiber composite part (composite part) of at least 60% fibers and up to 40% of the crosslinked 2K PU composition according to the invention. These fiber moldings show after crosslinking as a high mechanical stability. This is also given at elevated ambient temperatures.

Another object of the invention is a fiber composite material containing at least 60% synthetic fiber materials up to 40% of a cross-linking 2K-PU composition.

The 2K PU compositions according to the invention which exhibit incompatibility during mixing are particularly suitable for embedding fiber materials, for example for the infusion method or for the RTM method. In this case, the known fiber materials are arranged and incorporated in total into a polymer matrix. embedded. The composition shows good adhesion to the fiber substrates. Due to the reduced viscosity, an error-free matrix can be produced, in particular bubbles are avoided in the molded part. Another advantage is that the delayed reactivity allows good embedding of the fibers. Overheating of the composite parts is avoided, which also prevents damage to sensitive fiber materials. The phase separation of the mixture does not lead to a deterioration of the properties of the crosslinked polymers but improves the application properties.

Examples:

The following examples illustrate the invention. Example 1: Component A

Polyether triol (amine-free, Mn approx. 350)

Component B

MDI isomer mixture

NCO: OH ratio 1, 5: 1

Method: The components are mixed in a vessel with a high-speed agitator with exclusion of moisture, the mixture is then degassed in vacuo with stirring.

The ingredients were clearly cloudy after mixing for 3 min, 5 min, 7 min.

The ingredients were mixed and the viscosity (25 ° C) determined.

Viscosity start 190 mPas.

5 min. 270 mPas

10 min 480 mPas

There is a long open time.

Example 2: Components A and B are mixed together with 0.2% DABCO in NCO: OH ratio 1, 15: 1.

The mixture was still cloudy after 4 min and 7 min, respectively.

From the samples, test pieces (4 mm thick) were cast immediately after production and crosslinked at 95 ° C (45 min) and 130 ° C (60 min). ,

The crosslinked samples showed an E modulus of about 2700 MPa (25 ° C).

Claims

claims

1 . Containing two-component polyurethane composition

From 10 to 80% by weight of at least one polyol having a number-average molecular weight of from 200 g / mol to 3000 g / mol,

From 5 to 70% by weight of at least one aromatic polyisocyanate,

0 to 15% by weight of additives,

wherein the composition has an NCO: OH ratio of 2: 1 to 1: 2, the composition has a viscosity of 20 to 3000 mPas (EN ISO 2555, Brookfield Viscometer, 25 ° C) and shows a phase incompatibility after mixing and the Functionality of the polyol mixture is greater than 2.3

2. Two-component polyurethane composition according to claim 1, characterized in that the mixture has a viscosity of less than 1000 mPas (25 ° C).

3. Two-component polyurethane composition according to one of claims 1 or 2, characterized in that at least 50 mol% of isocyanate groups of MDI and its isomers are contained.

4. Two-component polyurethane composition according to one of claims 1 to 3, characterized in that are used as polyols polyester polyols and / or in particular polyether polyols having an average functionality of more than 2.5.

5. Two-component polyurethane composition according to any one of the preceding claims, characterized in that as a catalyst tertiary amines or Sn compounds, in particular Sn catalysts with polyhydroxy compounds as complexing agent, the Komplexbilnder of cyclic α-hydroxy ketones or 1-alkyl 2,3,4-triphenols is selected.

6. Two-component polyurethane composition according to one of the preceding claims, characterized in that the crosslinked composition has a glass transition temperature Tg above 60 ° C.

7. Two-component polyurethane composition according to any one of the preceding claims, characterized in that the amount of isocyanate groups by reaction to carbodiimides and its derivatives, in particular to uretimoimines, is reduced.

8. Two-component polyurethane composition according to one of the preceding claims, characterized in that the crosslinked composition has an E-modulus of more than 1000 MPa.

9. A method for producing fiber composites, wherein an outer mold is provided with fiber materials and in this form a liquid two-component polyurethane composition according to any one of claims 1 to 8 is introduced under pressure, wherein said composition is introduced in the state of phase incompatibility ,

10. The method according to claim 9, characterized in that fiber contents of more than 60% (volume%) are used based on the molding.

1 1 .Method according to one of claims 9 or 10, characterized in that the filled mold is cured at a temperature of up to 120 ° C.

12. The method according to any one of claims 9 to 1 1, characterized in that the composition is degassed immediately after mixing.

13. fiber composite material containing at least 60% synthetic fiber materials and up to 40% of a crosslinked two-component polyurethane composition obtainable from a composition according to any one of claims 1 to 8 ..

14. Fiber-reinforced material according to claim 13 or 14, characterized in that the matrix binder has a Tg above 60 ° C.