Prepregs and articles moulded therefrom

FIELD: chemistry.

SUBSTANCE: invention relates to prepregs, a method for production and use thereof, as well as a method of making components from composite material using said prepregs. The prepregs are made of A) at least one type of reinforcing fibres and B) at least one powdered polyurethane composition as a matrix material. Component B) contains: a) at least one urethdione group-containing curing agent based on products of polyaddition of aliphatic, (cyclo)aliphatic or cycloaliphatic polyisocyanates with urethdione groups and compounds with hydroxyl groups, which is in solid state at temperature below 40°C, in liquid state above 125°C and contains less than 5 wt % free NCO-groups and 3-25 wt % urethdione groups; b) at least one polymer with hydroxyl groups which is in solid state at temperature below 40°C, in solid state above 125°C and has a hydroxyl number of 20-200 mg KOH/g. Components a) and b) are used in a ratio of one hydroxyl group in component b) per 0.3-0.7 urethdione group in component a).

EFFECT: producing technologically effective, nontoxic polyurethane-based prepregs.

18 cl, 4 dwg

The invention relates to prepregs and obtained from them the details of the composite material (molded products), which can be produced by applying a powder of a reactive polyurethane compositions.

Various methods of forming, for example, the method of reaction injection molding, provide for the laying of the reinforcement fibers in the form, the circuit forms a load in the form of recipes with stitched resin and subsequent crosslinking of the resin, in typical cases implemented due to supply heat.

One of the problems that arise when implementing these technologies is the relative difficulty of laying of reinforcing fibers in the form. Separate tissue layers or layers composed of bundles of fibers must be cut to pieces, the dimensions of which correspond to the variable geometrical parameters of the form. The implementation of this technological operations along with time-consuming may be complicated, in particular, the need for the introduction of the molded core of foam or other materials. In such cases, desirable would be the use of reinforcing fibers with an easily implemented by the possibility of their pre-forming and modifying the form.

Reinforced fiber materials in the form of prepregs in the present BP is me find wide industrial application, due to the ease of completing the necessary technological operations and increased processing efficiency of these systems in comparison with alternative methods of wet molding plastic laminate (wet-lay-up Technologie).

Along with lesser duration of technological cycles and higher stability of the prepregs during storage to other requirements of industrial customers is also the possibility of automated cutting prepreg at room temperature and stacking of the individual layers without contamination of cutting tools matrix material, which often has the stickiness.

In the sphere containing slivaushiesia matrix systems in addition to polyesters, vinyl esters and epoxy resins used a number of specialized resins. The latter include polyurethane resins, which are due to the inherent fluidity, acceptability of defects and strength is used primarily for the production of shaped parts made of composites by pultrusion. The disadvantage of these resins are often referred to as the toxicity of the used isocyanates.

Polyurethane composite materials differ from composites based on vinyl esters, unsaturated polyesters or hybrid resins (mixtures of unsaturated korniholio with polyurethanes) higher fluidity.

Prepregs and obtained from them the composites based on epoxy resin systems are described, for example, in international application WO 98/50211, U.S. patent US 4992228, US 5080857 and US 5427725, patents great Britain GB 2007676 and GB 2182074, European patents EP 309221 and EP 297674, international application WO 89/04335, as well as in U.S. patent US 5532296, US 4377657 and US 4757120.

In the international application WO 2006/043019 described method of manufacture of prepregs based powdered combination of epoxy resin with polyurethane.

Also known prepregs based used as matrix material powdered thermoplastics.

In U.S. patent US 2004/0231598 described method, in accordance with which the particles are passed through a special accelerator chamber for electrostatic charges. A similar device is used for coating on substrates of glass, aramid or carbon fibers used for manufacturing prepreg of thermoplastic resins. As resins in the cited publication specified polyethylene, polypropylene, a simple peek, simple polyethersulfone, polyphenylsulfone, polyimide, polyamide, polycarbonate, polyethylene terephthalate, polyurethane, polyesters, and fluoropolymers. Derived from the above thermoplastic resin prepregs with a textile basis are characterized by intrinsic viscosity, optimum viscoelastic characteristics of the leader damping, unlimited suitability for storage, high resistance to chemical products and suitability for recycling.

In the international application WO 98/31535 described method of powder impregnation, in accordance with which subject the impregnated bundles of glass or carbon fibers at a certain velocity profile saturate the mixture of particles and liquid, respectively, a mixture of particles with gas. When this powder is ceramic, respectively thermoplastic materials, in particular thermoplastic polyurethane.

In the international application WO 99/64216 described prepregs and composite materials, as well as methods of their manufacture, in accordance with which use of the polymer emulsion particle size which is so small that they can form surrounding individual fibers of the shell. Polymers, which consist of particles which have a viscosity component of at least 5,000 centipoise, and are thermoplastics or schilawski polyurethanes.

In the European patent EP 0590702 described is used for the manufacture of prepregs powdered impregnating compositions, and the powder is a mixture of thermoplastics with reactive monomer, respectively prepolymers.

The use of thermoplastics for the manufacture of prepregs described in international application WO 2005/091715.

Also published in the Annual Technical Conference - Society of Plastics Engineers (1991), 49, 2065-9, report MA, C. C. M., Chiang, S. L, "Processing and properties of thermoplastic polyurethane prepreg" known thermoplastic polyurethane prepregs based thermoplastic polyurethane systems containing solvents and water.

Also known prepregs with a matrix based on two-component polyurethanes.

Under the two-component polyurethanes mean mainly classical reactive polyurethane system. In principle these systems, consisting of two separated from other components. The main component of such systems is always a polyisocyanate, whereas the second component using polyhydric alcohols or, in accordance with the new developments, the mixture of amines or amine with a mixture of polyhydric alcohol. Both of these component are mixed with each other shortly before processing. Then carry out a chemical curing by polyaddition, followed by the formation of a grid of polyurethane, respectively polyurea.

Two-component system after mixing the respective components are characterized by limiting the productive time of the suitability for processing (limited viability), since starting reaction between the components leads to a gradual increase in the viscosity of the system, ending with gelation. Thus the effective time, the suitability of such systems for processing will be determined by many factors, the most important of which are the reactivity of the reagents, catalysis, concentration, solubility, moisture content, the ratio of the number of isocyanate groups to the number of hydroxyl groups and the ambient temperature [see Lackharze, Stoye/Freitag, publisher Hauser, 1996, cc.210/212].

Lack of prepregs based on such two-component polyurethane systems is too short a time to their suitability for processing in the composite material. In accordance with these prepregs remain stable during storage over a period of time not exceeding a few hours.

Below polyurethane prepregs, respectively, of composite materials based on two-component polyurethane systems are considered in more detail.

Article K. Recker "Voured - ein neuer Polyurethan-Werkstoff für das Harz-mattenverfahren" (Recker Klaus, Kunststoffe-Plastics, 8,1981) reported the development of two-component polyurethane system used in SMC technology (sheet molding compound), with a special focus on technological properties of systems for which proizvodstva SMC-details.

In the international application WO 2005/049301 described catalytically activated two-component polyurethane system, the polyisocyanate component which is mixed with a polyhydric alcohol, and the mixture is processed into a composite by pultrusion.

In the international application WO 2005/106155 described fiber reinforced composite material for the construction industry, which is obtained by molding two-component polyurethane systems containing long fiber filler.

In Japanese patent JP 2004196851 described composite materials, which are made of carbon and organic fibers, such as hemp, using the matrix as a two-component polyurethane-based polymer etilendiamindisuktsinatov and special compounds containing hydroxyl groups.

In the European patent EP 1319503 described polyurethane composite materials, and as a two-component polyurethane impregnated with resin fibrous laminate surrounding the core layer (for example, paper honeycomb), use special polyurethane outer layers. Two-component polyurethane resin based on, for example, methylenedianiline and mixtures of polypropilencolour with dialami copolymers of ethylene oxide with propylene oxide.

In the international application WO 2003/101719 OPI is Ana-based polyurethane composites and methods of their manufacture. It is about a two-component polyurethane resins, characterized by a certain viscosity and specific gelation time.

Two-component polyurethane systems are also described in the article "Fiber reinforced polyurethane composites: shock tolerant components with particular emphasis on armor plating" (Ratcliffe, Colin P., Crane, Roger M., Santiago, Armando L, AMD (1995), 211, Innovative Processing and Characterization of Composite Materials, 29-37), as well as the report "Fiber-reinforced polyurethane composites. I. Process feasibility and morphology" (Ma Chen Chi M., Chen Chin Hsing, International SAMPE Symposium and Exhibition (1992), 37 (Mater. Work. You 21st Century), 1062-74).

Two-component systems, both in terms of composition, and properties, to the maximum extent possible (except binding) correspond to the moisture curing varnishes. In both cases, use in principle the same solvents, pigments, fillers and auxiliary components. However, unlike varnishes to be the application of two-component systems is not allowed the presence of moisture due to the need to ensure their stability.

Known also physically drying systems based on directionspublic polyurethane elastomers. The concern of high molecular weight linear thermoplastic urethanes based on diols and diisocyanates, preferably etilendiamindisuktsinatov, toluylene diisocyanate, hexamethylenediisocyanate or isophorondiisocyanate. Such Ter is plasticine system, as a rule, have a very high viscosity and, therefore, are to be processed at extremely high temperatures. This circumstance complicates their use for the manufacture of prepregs.

The use of powders for the manufacture containing fibrous material prepregs in the case of reactive systems is quite unusual technology and is currently limited to a few areas. However, perhaps the most common technique involves the application of powder on the surface of the fiber in a fluidized bed (fluidized bed impregnation revision). Moving in moving up the stream, the powder particles pass into a condition in which exhibit properties characteristic of liquids.

The use of such technologies is provided in European patent EP 590 702. While powder coating is applied on the wiring, woven from individual fascicles. For the formation of a matrix with optimal properties use a powder that is a mixture of reactive and thermoplastic polymers. In conclusion, carry styling individual runic (bundles of fibers) and pressing several layers under the pressure of 16 bar for a period of time of about 20 minutes. The temperature of the pressing range from 250 to 350°C. However, the result is implemented in a fluidized bed coating powders especially in the absence of disconnection of the harness, are often formed uneven coverage.

A method such as coating powders in a fluidized bed as described in U.S. patent US 20040231598. The stream of air moves the powder to the substrate, the powder particles are uniformly deposited on where through the use of special devices.

Another method is described in U.S. patent US 20050215148. Using the above devices provide uniform distribution of the powder particles on the fibers. The particle size of the powder is from 1 to 2000 μm. In some experiments, the coating is applied on one or both sides. Thanks to the uniform application of the powder in the subsequent pressing prepreg is formed of a multilayer material without air inclusions.

In the international application WO 2006/043019 described the use of powdered polymers with epoxy and amine terminal groups. When the powders are mixed together and the mixture is applied on the fiber. Then carry out the sintering of the powder particles. The particle size of the powder is from 1 to 3000 μm, preferably from 1 to 150 microns.

Limiting the size of the particles is also recommended in a study published by the University of Michigan. This study is based on theoretical premise that the particles of smaller diameter easily penetrate into promesed settled between individual elementary fibers, than particles larger diameter (S. Padaki, L. T. Drzal, A simulation study on the effects of particle size on the consolidation of polymer powder impregnated tapes, Department of Chemical Engineering, Michigan State University, Composites: part a (1999), cc.325-337).

System reactive powders are used not only in the technique of prepregs, but in the other classical methods, for example, in the technique of coiling [M. N. Ghasemi Nejhad, K. M. Ikeda: Design, manufacture and characterization of composites using on-line recycled thermoplastic powder impregnation revision of fibres and in-situ filament winding, Department of Mechanical Engineering, University of Hawaii at Manoa, Journal of Thermoplastic Composite Materials, vol. 11, cc. 533-572, November 1998] or pultruded technology. In the case of pultruded fibre bundles (Towpregs), for example, provide powder coating, wound and stored primarily in the form of so-called material Towpregs. On the possibility of producing such material is reported in an article published in the journal of the society of engineers aerospace materials and technology (SAMPE) [R. E. Allred, S. P. Wesson, D. A. Babow, Powder impregnation revision studies for high temperature towpregs, Adherent Technologies, SAMPE Journal, vol 40, no .6, cc.40-48, November/December 2004]. According to another study materials type Towpregs pressed in accordance with pultruded technology and utverjdayut, getting parts made of composite material [N. C. Parasnis, K. Ramani, H. M. Borgaonkar, Ribbonizing of electrostatic powder spray impregnated thermoplastic tows by pultrusion, School of Mechani-cal Engineering, Purdue University, composites, Part A, Applied science and manufacturing, volume 27, cc.567-574, 1996]. Ho what I know about the production of materials type Towpregs using thermosetting systems and their subsequent pressing in accordance with the technique of pultrusion, however, until recently, to implement such technology in most cases the use of thermoplastic system.

The present invention was based on the task to offer technologically advanced, non-toxic prepregs based on polyurethane, which does not possess the disadvantages of the prior art, that is inherent to thermoplastic polyurethane systems for high viscosity and, therefore, the problems occur when the impregnation of the latter fibers, or fabrics, and low vitality characteristic of two-component polyurethane systems. Another objective of the present invention consisted in the fact that the polyurethane matrix material of the above prepreg can be obtained by a simple method, and the main attention should be paid to the technological properties of the prepregs and their stability during storage.

Matrix materials proposed in the invention prepregs in unstitched condition preferably should have a low enough viscosity to ensure wetting their fibrous bases in the manufacture of parts made of composite material, preferably may be also the presence of thixotropy of these materials, in order to prevent leaking of resin in vertically arranged segments produced from the components of the investment material details.

Thanks to the choice for the fabrication of a matrix material appropriate starting substances can provide the necessary processing of the matrix material the period of time between its melting and completion of the interaction of its constituent components, which is determined by the technology of the manufacture of the composite material.

It has been unexpectedly discovered that the use of containing uretdione group reactive powdery polyurethane compositions allows to obtain stable during storage polyurethane prepregs, which retain their reactivity and, therefore, suitable for crosslinking occurring during the manufacture of parts made of composite material, and these prepregs can be used for making effective composite materials, which are suitable for use in various fields, including construction, automotive, aviation and space industry, energy (wind turbines), as well as shipbuilding, including small shipbuilding. Used according to the invention containing uretdione group reactive powdery polyurethane compositions are environmentally safe, optimum mechanical properties, simplicity is pererabotki, and high weather resistance after completion of curing, in particular, a balanced ratio between hardness and flexibility.

The object of the present invention is a prepreg, mainly consisting of:

A) at least one fibrous substrate and

B) at least one reactive powdery polyurethane composition as the matrix material.

Proposed in the invention prepregs have an extremely high stability in storage conditions at room temperature, if the glass transition temperature of the matrix material is at least 40°C. depending on the content in the prepreg reactive powdery polyurethane composition of their stability in storage conditions at room temperature is at least a few days or weeks, whereas at 40°C it usually takes several days.

Prepregs after their application and fixation implemented preferably by heat treatment, preferably by sintering reactive powdery polyurethane composition occurring without its staple, characterized by the absence of stickiness, and therefore, perfectly suitable for the implementation of technological operations and processing. Therefore, IP is alzhemier according to the invention the reactive powdery polyurethane composition characterized by extremely high adhesion and uniformity of the fibrous-based.

In the process of further processing of prepregs in the composites (composite materials), implemented, for example, by pressing at elevated temperatures, low viscosity liquid reactive polyurethane compositions extremely effectively impregnate the fibrous basis due to their excellent ability to moisten the fibers, and impregnating a fibrous basis happens to occur at elevated temperatures of the crosslinking reactive polyurethane compositions, respectively, prior to gelation, coming at full curing polyurethane matrix.

Depending on the composition of the used reactive powdery polyurethane composition and if necessary add catalysts can widely be varied as the speed of the crosslinking reaction in the manufacture of parts made of composite material, and the properties of the resulting matrix.

In accordance with the invention under matrix material imply the above reactive powdery polyurethane composition used for the manufacture of prepregs, which is located on the fibers in a fixed, respectively adhered state, while retaining its inherent reactivity. In accordance with the invention under the matrix implies the live stitched inside the composite matrix materials, formed from the reactive powdery polyurethane compositions.

Basis

In accordance with the present invention the fibrous base is a fibrous material (also frequently referred to as the reinforcing fiber material). Suitable materials fibers in General is any substance, however, preferred are fibrous materials made of glass, carbon, polymers, such as polyamide (aramid) or polyesters, natural fiber or mineral volokita, such as basalt or ceramic fiber (fiber-based oxides of aluminum and/or silicon oxides). In addition, you can use a combination of fibers of different types, for example, the combined fabric of aramid and glass fibers or carbon and glass fibers. It is possible to make hybrid parts made of composite material prepregs which contain different fibrous basis.

The most commonly used fibers include glass fibers, primarily because of their relatively low cost. In this case, in principle, suitable reinforcing fibers of glass of any type (F, S, R, M, C, ECR, D or AR) or hollow glass fibers.

Carbon fiber in General use in the composition of high performance composite mother of the crystals, for a particular value has a lower density than glass fiber reinforced materials, combined with high durability. Carbon fibers on an industrial scale produced from the source material in which carbon by pyrolysis is converted into graphite-like carbon. There are carbon fiber isotropic or anisotropic types, and isotropic carbon fibers have little strength and have less technical value, while anisotropic fibers have high strength and stiffness combined with low breaking elongation.

As natural fibers in this case you can use any textile fibers and fibrous materials based on raw materials of vegetable and animal origin (for example, wood fibers, cellulose, cotton, hemp, jute, flax, sisal or bamboo).

Aramid fibers like carbon fibers have negative values of the coefficient of thermal expansion, which leads to their reduction when heated. Specific strength and modulus aramid fibers is much lower compared to carbon fibers. The use of aramid fibers in combination with a matrix resin, characterized by positive values of the ratios are the NTA of linear expansion, allows to produce parts with high ability to maintain the specified dimensions. Unlike reinforced carbon fiber polymer composite material based on aramid fibers have a much lower compressive strength. To well-known trademarks aramid fibers include Nomex® and Kevlar® by Dupont, and Teijinconex®, Twaron® and Technora® company Teijin. Especially suitable and preferred are the basics of glass, carbon, aramid or ceramic fibers.

Under the fibrous material according to the invention involve textile product flat shape. Suitable are textiles flat shape of the fibrous mass, the product of machine knitting, in particular, of knitted and crocheted products, as well as navatanee pasma, such as cloth, nonwoven cloth or woven products. In addition, suitable bases can be long fiber or short-fiber materials. According to the invention suitable fibrous bases include also rovings and yarn. According to the invention as fibrous bases fit any of the above materials.

Overview of reinforcing fibers are presented in the publication Composites Technolo-gien, Paolo Ermanni (Version 4), Script zur Vorlesung ETH, Zurich, August 2007, Chapter 7.

Matrix material

As matrix materials in principle prigodilsya powdered reactive polyurethane composition. Suitable polyurethane compositions according to the invention are a mixture of the polymer (b) (binder) with functional groups reactive towards isocyanate groups, also called resin, and temporarily deactivated, which means internally locked and/or blocked with blocking agents, di - or polyisocyanates, also known as hardeners a).

Suitable functional groups of the polymer (b) (binder) are hydroxyl groups, amino groups and mercaptopropyl that interact with the free isocyanate groups by reaction of the merger, providing the crosslinking and curing of the polyurethane composition. Connecting components must possess the intrinsic properties of the solid resin (glass transition temperature greater than room temperature). Suitable binders are polyesters, polyethers, polyacrylates, polycarbonates and polyurethanes with a hydroxyl number of from 20 to 500 mg KOH/g and an average molecular weight of from 250 to 6000 g/mol. Particularly preferred binders are containing hydroxyl groups polyesters or polyacrylates with a hydroxyl number of from 20 to 150 mg KOH/g and an average molecular weight of from 500 to 6000 g/mol. Obviously, you can also use a mixture of these polymers. STA is in containing functional group of the polymer (b) is chosen so that to each functional group of the component (b) had from 0.3 to 0.7 uretdione group of the component (a).

Suitable hardeners a) are blocked by blocking agents or internally blocked (uretdione) di - and polyisocyanates.

Used according to the invention, di - and polyisocyanates can be any aromatic, aliphatic, cycloaliphatic and/or (cyclo)aliphatic di - and/or polyisocyanates.

Suitable aromatic di - or polyisocyanates are, in principle, any known aromatic compounds. Particularly suitable 1,3 - and 1,4-delete the entry, 1,5-naphthylenediisocyanate, solidinvestment, 2,6-tolylenediisocyanate, 2,4-tolylenediisocyanate (2,4-TDI), 2,4'-diphenylmethanediisocyanate (2,4'-MDI), 4,4'-difenilmetana-diisocyanate, mixtures of Monomeric diphenylmethanediisocyanate (DHS) with the oligomeric diphenylmethanediisocyanate (polymeric MDI), xylylenediisocyanate, tetramethylethylenediamine and triisocyanate.

Suitable aliphatic di - or polyisocyanates predominantly contain from 3 to 16 carbon atoms, preferably from 4 to 12 carbon atoms in an unbranched or branched Allenova residue, while suitable cycloaliphatic or (cyclo)aliphatic diisocyanates predominantly contain from 4 to 18 carbon atoms, PR is doctitle from 6 to 15 carbon atoms in cycloalkylation residue. Under the (cyclo)aliphatic diisocyanates imply well-known specialists compounds, isocyanate groups which are simultaneously connected with cyclic and aliphatic residues, for example, as in the case of isophorondiisocyanate. In contrast, under a cycloaliphatic diisocyanates include compounds, isocyanate groups are attached directly to the cycloaliphatic ring, for example, as in the case of diisocyanatohexane (H₁₂DHS). Their examples are cyclohexanediethanol, methylcyclohexylamine, ethylcyclohexylamine, propylcyclohexanone, methyldicyclohexylamine, propertisation, potentisation, incandescent, exanguination, heptadienal, octadienal, noninvestment, nonintrusiveness, for example, 4-isocyanatomethyl-1,8-octadienal (triisocyanate, TIN), decongestant, decentralization, underinvestment, undecanedioic, dodecanesian and dodecanesian.

Preferably use isophorondiisocyanate, hexamethylenediisocyanate, diisocyanatohexane (H₁₂MDI), 2-methylpentadiene, 2,2,4-trimethylhexamethylenediamine/2,4,4-trimethylhexamethylenediamine or norbornadiene. More preferably used is isout isophorondiisocyanate, hexamethylenediisocyanate, trimethylhexamethylenediamine and H₁₂DHS, as well as isocyanurate.

Suitable are also 4-methylcyclohexane-1,3-diisocyanate, 2-butyl-2-etilinlestradiola, 3(4)-isocyanatomethyl-1 metallic-logicalsounds, 2-isocyanatopropyltrimethoxysilane, 2,4'-Methylenebis(cyclohexyl)diisocyanate and 1,4-diisocyanato-4-methylpentane.

Obviously, you can also use a mixture of di - and polyisocyanates.

In addition, it is preferable to use oligopotent or polyisocyanates which can be obtained by combining the above diisocyanates, polyisocyanates or mixtures thereof by means of urethane, allophanate, urea, biuret, uretdione, amide, which, carbodiimide, uretonimine, oxidization or iminoimidazolidine structures. Particularly suitable are isocyanurate obtained, in particular, from isophorondiisocyanate and hexamethylenediisocyanate.

Used according to the invention, the polyisocyanates are blocked connections. For blocking polyisocyanates use external blocking agents, such as ethylacetoacetate, Diisopropylamine, methylethylketoxime, diethyl ester of malonic acid, ε-caprolactam, 1,2,4-triazole, phenol, or substituted phenol, or 3,5-dimethylpyrazol is.

Preferred curing components contain adducts of isophorondiisocyanate, which grouping, and blocked with ε-caprolactam isocyanate structure.

Possible and preferably used is an internal blocking. Internal blocking of the isocyanate implement via formed in the dimerization uretdione structures at elevated temperatures are split on the original isocyanate structure and, therefore, provide the binding.

Reactive powdery polyurethane composition may optionally contain additional catalysts. The concern of ORGANOMETALLIC catalysts, such as dilaurate dibutylamine, octoate zinc or neodecanoate bismuth, or tertiary amines have had, such as 1,4-diazabicyclo[2.2.2.]octane used in an amount of from 0.001 to 1% of the mass.

For the manufacture of reactive powdery polyurethane compositions can be added known from powder technology conventional additives, in particular, to contribute to spreading, for example, polysilicones or acrylates, light stabilizers, for example, spatial employed amines, or other accessories, see, for example, in European patents EP 669 353, in General it is a number from 0.05 to 5% by mass. The amount of added fillers and pigments, such as titanium dioxide, can reach 30% of the mass. of the total composition.

In accordance with the present invention the definition of "reactive" means that the curing is used according to the invention polyurethane compositions occurs at temperatures between 160°C and depends on the type of basics.

Used according to the invention the reactive powdery polyurethane composition in normal conditions, for example, when using laurate dibutylamine as a catalyst, otverzhdajutsja at temperatures from 160°C., usually from about 180°C. the duration of curing used according to the invention polyurethane compositions typically corresponds to a time interval from 5 to 60 minutes.

A preferred object of the present invention is a prepreg with a matrix material containing uretdione group reactive powdery polyurethane compositions, mainly consisting of:

a) at least one containing uretdione groups of the hardener on the basis of addition polymerisation products of polyisocyanates with aliphatic, (cyclo)aliphatic or cycloaliphatic uretdione groups and compounds with hydroxyl groups at a temperature below 40°C is in the TV is rdeu form and at temperatures above 125°C in liquid form and contains less than 5% of the mass. of free NCO-groups and from 3 to 25% of the mass. uretdione groups,

b) at least one polymer with hydroxyl groups at a temperature below 40°C is in solid form, and at temperatures above 125°C in liquid form, and has a hydroxyl number of from 20 to 200 mg KOH/g,

c) optionally at least one catalyst and

d) if necessary, known from polyurethane chemistry of auxiliary substances and additives,

moreover, the components a) and b) are used in such proportions that for each hydroxyl group of component b) were from 0.3 to 0.7, preferably from 0.45 to 0.55 uretdione groups of component a). The latter condition means that the NCO/OH-ratio is 0.9-1.1:1.

Containing uretdione groups of the polyisocyanates are well known and described, for example, in U.S. patents US 4476054, US 4912210 and US 4929724, as well as in the European patent EP 417603. A comprehensive overview of suitable industrial methods for the dimerization of isocyanates in uretdione described in J. Prakt.Chem. 336 (1994), cc.185-200. The conversion of isocyanates in uretdione in General carried out in the presence of soluble catalysts for the dimerization, such as dialkylaminoalkyl, trialkylphosphine, triamide phosphorous acid or imidazoles. Upon reaching the desired extent into the dimerization I, which is optionally carried out in solvents, preferably in the absence of solvents, stop by the addition of catalytic poisons. Immediately after this, the excess Monomeric isocyanate is separated by evaporation in high vacuum. In the case of the relatively high volatility of the catalyst can be removed from the reaction mixture in the process of selection of the monomer. You can refuse to add a catalytic poisons. To obtain containing uretdione groups of the polyisocyanates is in principle possible to use a wide range of isocyanates. For this purpose you can use the above di - and polyisocyanates. However, preferred are the di - and polyisocyanates selected from the group including any aliphatic, cycloaliphatic and/or (cyclo)aliphatic di - and/or polyisocyanates. According to the invention using isophorondiisocyanate, hexamethylenediisocyanate, diisocyanatohexane (H₁₂MDI), 2-methylpentadiene, 2,2,4-trimethylhexamethylene-diisocyanate/2,4,4-trimethylhexamethylenediamine or norbornadiene. Even more preferably use isophorondiisocyanate, hexamethylenediisocyanate, trimethylhexamethylenediamine or H₁₂DHS, as well as isocyanurate.

For the manufacture of a matrix material, more preferably the use isophorondiisocyanate and hexamethylenediisocyanate.

The transformation above containing uretdione groups of the polyisocyanates in the containing uretdione group hardeners a) implement by reacting the free isocyanate groups containing hydroxyl groups, monomers or polymers, such as polyesters, polythioether, polyethers, polycaprolactone, polyepoxide, complex polyetherimide, polyurethanes or low-molecular diatomic, triatomic and/or chetyrehtomnik alcohols used as chain-extending agents, and the monoamines and/or monohydroxy alcohols, optionally used as agents of breakage of the chains (the specified transformation is described in European patents EP 669353, EP 669354, German patent DE 3030572, and in European patents EP 639598 and EP 803524). For the specified transformation is preferably used polyesters and Monomeric diatomic alcohols. Preferred hardeners a) uretdione groups contain less than 5% of the mass. free isocyanate groups and from 3 to 25 wt. -%, preferably from 6 to 18% of the mass. uretdione groups (calculated as C₂N₂O₂with the molecular weight 84). Preferred are polyesters and Monomeric diatomic alcohols. In addition uretdione groups hardeners a) can also contain, which, biuret, allophanate, Uryadovy and/or urea structures.

As polymer b) with a hydroxyl group is preferably used polyesters, polyethers, polyacrylates, polyurethanes and/or polycarbonates with hydroxyl numbers in the range from 20 to 200 mg KOH/g is Particularly preferred to use polyesters with a hydroxyl number in the range from 30 to 150 mg KOH/g and an average molecular weight in the range from 500 to 6000 g/mol, which is at a temperature below 40°C are in solid form, and at temperatures above 125°C in liquid form. Binders of this type are described, for example, in European patents EP 669 354 and EP 254152. Obviously, you can also use a mixture of these polymers. Number containing the hydroxyl group of the polymer (b) is chosen so that for each functional group of the component (b) had from 0.3 to 0.7, preferably from 0.45 to 0.55 uretdione group of the component (a).

Reactive powdery polyurethane composition may optionally contain additional catalysts. The concern of ORGANOMETALLIC catalysts, such as dilaurate dibutylamine, octoate zinc or neodecanoate bismuth, or tertiary amines have had, such as 1,4-diazabicyclo[2.2.2.]octane used in an amount of from 0.001 to 1% of the mass.

For the manufacture of reactive powder polyuretha the new songs you can add known from powder technology conventional additives d), in particular, tools that facilitate the spreading, for example, polysilicones or acrylates, light stabilizers, for example, spatial employed amines, or other accessories, see, for example, in European patents EP 669 353, in total amount of from 0.05 to 5% by mass. The amount of added fillers and pigments, such as titanium dioxide, can reach 30% of the mass. of the total composition.

Used according to the invention the reactive powdery polyurethane composition in normal conditions, for example, when using laurate dibutylamine as a catalyst, otverzhdajutsja at temperatures from 160°C., usually from about 180°C.

The impregnated fibrous bases used according to the invention the reactive polyurethane compositions takes place in an extremely favorable conditions, and therefore, these compositions are well suited for impregnation, and after curing, they have excellent resistance to chemical products. In the case of aliphatic cross-linking agents (for example, isophorondiisocyanate or H₁₂DHS) in addition reach a high weather resistance.

Reactive powdery polyurethane composition used according to the invention as matrix material is material, at room temperature are in the form of a non-sticky solid powders. These compositions are a mixture consisting mainly of reactive resin and hardener. The glass transition temperature of this mixture is at least 40°C, and the interaction of its constituent components, followed by the formation of cross-linked polyurethane, and therefore, formation of the matrix of a composite material, usually occurs only in the temperature region above 160°C. This means that proposed in the invention prepregs after their manufacture is composed of a substrate and a deposited reactive powdery polyurethane composition as the matrix material, which is unstitched, but reactive state. Thus, these prepregs are stable in storage and, therefore, suitable for further processing into composite materials for a period of time amounting to several days and even weeks. In this lies the essential difference between these prepregs from the above unstable during storage of two-component systems, reactive components which interact, followed by the formation of polyurethanes and stitching, directly after application.

Homog is the organization of all components of polyurethane compositions, intended for the manufacture of prepregs can be carried out in suitable for this purpose devices, such as a heated reactor with agitator, mixers or extruders, and a maximum temperature of homogenization should not be above 120-130°C. the Mixing of the individual components is preferably carried out in an extruder at temperatures above their melting point but below the temperature at which the reaction begins stitching. The resulting mass after hardening grind and optionally separated into fractions (for example, with the diameter of particles less than 63 microns, from 63 to 100 μm and about 100 μm), for example, by sifting.

The object of the present invention is also the application of the proposed invention the reactive powdery polyurethane compositions for the manufacture of prepregs, primarily containing fibrous reinforcing the basics of glass, carbon or aramid fibers, and production of composite materials from the obtained prepregs.

The manufacture of prepregs, in principle, can be done by any means, but it is preferable powder impregnation. In a suitable embodiment, the reactive powdery polyurethane composition is applied to the substrate by the method of dispersion. Applying powder compositeimage to carry out the method of the vortex spraying, pultrusion or spraying.

When performing powder impregnation of the matrix material, which is typically a thermoplastic polymer is in powder form. According to the prior art to provide the shortest possible path for the flow of high-viscosity melt thermoplastic matrix systems, the powder of thermoplastic with the purpose of wetting and encapsulating fibers are usually dispersed in a fluidized bed in a stream of air, which occurs simultaneously extracting elementary fibers. This facilitates the movement of individual particles of the powder to separate the fibers. The presence of electrostatic charge on the surface of the powder particles can further increase their ability to adhere to the fibers. After passing through the fluidized bed of elementary fibers with loosely adhered particles of the powder passed through a heating zone, in which melting occurs powdered matrix polymer. In the subsequent manufacturing of parts made of composite material to further improve the wetting of elementary fibers it is necessary to implement the operation of the seal.

In accordance with the projects according to the invention by the application of the proposed invention the reactive powdery polyurethane composition necessity in the unqualified use description the Noah higher-reducing technology trajectory melt flow is absent, since the melt of the prepolymers (unstitched molten powder) has low viscosity, it is sufficient to wet the fibers, which is a significant advantage of the invention prepregs compared with the prior art.

Nefrackzionirovannam powder or a separate faction powder applied on the fibrous base, for example, on the canvas in the form of a composite layer consisting of bundles of glass, carbon or aramid fibers, or fabrics made from these fibers, preferably the method of dispersion, and then fixed. In order to avoid losses of powder supplied powder fibrous base preferably immediately after the dispersion is heated in the heating zone, for example, via infrared emitters, which leads to sintering of polymer particles, and to prevent chemical reactions in reactive matrix material, the temperature of heating should not exceed 80-100°C. For imparting the prepregs of one or the other, if necessary, can be combined and cut.

The object of the present invention is also a method of manufacturing a prepreg by applying component B) to component a), preferably performed by the method of dispersion, and optionally fixing component C) preferably under the action of the heat, especially preferably by sintering.

For sealing layers of the prepreg in a single composite (detail) and bound proposed in the invention the matrix material, followed by the formation matrix, the prepreg is cut, if necessary, sew with each other or fixed in any other way, and then pressed in a suitable form under pressure and optionally under vacuum. In accordance with the present invention is similar to the process of manufacturing the composite materials of the invention prepregs depending on the time of curing is carried out in a temperature range slightly above 160°C.

The object of the present invention is also the use of prepregs, mainly consisting of:

A) at least one fibrous substrate and

B) at least one reactive powdery polyurethane composition as the matrix material,

for the manufacture of composite materials used in shipbuilding, including small shipbuilding, aviation and space technology, in the automotive industry, for two-wheeled vehicles, preferably motorcycles and bicycles in the areas of transport, construction, medical equipment and sports in the electrical and electronics industry, as well as for power plants, in the example, blades of wind power plants.

In addition, an object of the present invention are produced from the proposed invention prepreg parts made of composite material, consisting of:

A) at least one fibrous substrate and

B) at least one crosslinked polyurethane composition, preferably containing uretdione groups of the polyurethane composition as a matrix.

The object of the present invention is also a method of manufacturing parts made of composite material, the prepreg consisting of:

A) at least one fibrous substrate and

B) at least one reactive powdery polyurethane composition, preferably containing uretdione groups of the polyurethane composition as a matrix material,

made at temperatures above 160°C, preferably above 180°C., optionally with the use of pressure and/or vacuum.

The following examples serve for a more detailed explanation of the present invention.

Examples

In Fig.1 shows the laboratory scattering device Villars Minicoater 200 used for the manufacture of prepregs.

Used fiberglass non-woven cloth/fabric

To run the examples using glass fiber non-woven cloth/tissue, called the by following the basics of type I and type II.

As the basis of the type I use fabric of E-glass fibers 281 L (item # 3103) firm "Schlosser & Cramer". The mass of a specified tissue, referred to the unit area is 280 g/m².

As the basis of type II uses stitched biaxial woven fabric of E-glass fibers (-45/+45) GBX 600 (item # 1023) firm "Schlosser & Cramer". These two are superimposed on each other at an angle of 90 degrees layers, consisting of bundles of optical fibers. This design connected desteklenen fibers. The surface of the glass fibers is equipped with a modified aminosilane standard dressing. The mass of this material, referred to the unit area of 600 g/m².

Measurements by the method of differential scanning calorimetry

To perform in accordance with DIN 53765 research materials by the method of differential scanning calorimetry (definition of glass transition temperature and measuring the enthalpy of reaction) using the calorimeter Mettler Toledo DSC 821e.

Reactive powdery polyurethane composition

For the manufacture of prepregs and composite materials using reactive powdery polyurethane composition, which composition (% wt.) shown in the table below.

Listed in table shredded the original substance are thoroughly mixed in the mixer for mixing, and then homogenized in an extruder at a temperature of not higher than 130°C. the Extrudate after cooling, crushed and subjected to grinding in a rod mill. The average diameter of the particles used sieve fraction from 63 to 100 microns.

Physical properties

Listed below are the optimal conditions for sintering in the manufacture of prepregs on the above mini device that has been installed in a series of preliminary experiments.

The nonwoven fabric of glass fibers, the velocity of which is about 1.2 m/min, put about 150 g/m²powdery polyurethane composition. This corresponds to a layer thickness of about 500 microns, with RMS errors of about 45 microns.

When power IR emitters 560 W prepregs can be obtained with temperatures ranging from 75 to 82°C, at which sintering of reactive powdery polyurethane composition, and while this composition retains reactivity sintering occurs regardless has a visible powder powder structure or on the basis of glass fibers in a completely molten state.

The stability of the prepregs during storage

Stability prerecovery storage is determined by controlling the enthalpy of the reaction of crosslinking by the method of differential scanning calorimetry. The corresponding results are shown in Fig.2 and 3.

The ability of polyurethane prepregs to the stitching does not decrease during storage at room temperature over a period of time of at least 7 weeks.

The manufacture of parts made of composite material

Details of the composite material was obtained in accordance with well-known specialists in the technique of pressing using a press for the manufacture of composites. Obtained through dispersion device homogeneous prepregs pressed into composite materials on the table press. As the last used device Polystat 200 T company Schwabenthan, on which the prepreg is pressed into plates of the respective composites at a temperature of from 120 to 200°C. the Pressure varies in the range from normal pressure up to 450 bar. For better wetting of the fiber pressing is preferably carried out in a dynamic mode, i.e. when the AC supply pressure determined by the size and thickness you want to manufacture parts type polyurethane composition, and therefore its viscosity at the temperature of processing.

In one example the temperature of the press component 90°C, while the melting point was raised to 110°C, and on completion of the melting pressure for three minutes increase to 440 bar, and then Dean is practical mode varies in the interval from 150 to 440 bar (seven different values of pressure, the exposure duration of each of which is one minute), continuously increasing the temperature to 140°C. then the temperature was raised to 170°C, while maintaining the pressure 350 bar up to carry out after 30 minutes of extraction of parts made of composite material from the press.

Then by the method of differential scanning calorimetry to assess the degree of cure obtained a hard, tough, resistant to chemicals and impact resistant parts made of composite material in the form of plates with a volume content of fibers more than 50%. Determination of glass transition temperature curable matrix allows you to control the flow of the fusion process at different temperatures curing. The stitching used in the examples of the polyurethane composition is completed in approximately 25 minutes; however, there is also a lack of heat dissipation caused by the enthalpy of the reaction stitching. The corresponding results are shown in Fig.4.

In absolutely identical conditions produce two samples of composite material, and then determine and compare their properties. The results of determining the interlaminar strength shear (ILSF) confirm the high reproducibility of the properties of the composites. The average interlayer strength shear (ILSF) is 40 N/mm².

1. Prepregs, on the RAM is made of:
A) at least one type of reinforcing fibers and
B) at least one powdery polyurethane composition as the matrix material, mainly containing:
a) at least one containing uretdione group hardener based on the products of polyaddition of aliphatic, (cyclo)aliphatic or cycloaliphatic polyisocyanates with uretdione groups and compounds with hydroxyl groups at a temperature below 40°C is in solid form, and at temperatures above 125°C in liquid form and contains less than 5% of the mass. of free NCO-groups and from 3 to 25% of the mass. uretdione groups,
b) at least one polymer with hydroxyl groups at a temperature below 40°C is in solid form, and at temperatures above 125°C in liquid form and has a hydroxyl number of from 20 to 200 mg KOH/g, '
moreover, the components a) and b) are used in such proportions that for each hydroxyl group of component b) is from 0.3 to 0.7 uretdione group of the component (a).

2. Prepregs under item 1, characterized in that the powdery polyurethane composition) further comprises at least one catalyst.

3. Prepregs under item 1, characterized in that the powdery polyurethane composition In addition contains known from polyurethane chemistry excipients and obuvki.

4. Prepregs under item 1, characterized in that components (a) and (b) in powdery polyurethane compositions) are used in such proportions that for each hydroxyl group of component b) is from 0.45 to 0.55 uretdione group of the component (a).

5. Prepregs under item 1, and the glass transition temperature of the matrix material is at least 40°C.

6. Prepregs under item 1, characterized in that at least one type of reinforcing fibers contained material from glass, carbon, polymers such as polyamide (aramid) or complex polyester, natural fibers or mineral fibers such as basalt or ceramic fiber.

7. Prepregs under item 1, characterized in that at least one type of reinforcing fibers they contain textiles flat shape of the fibrous mass, the product of machine knitting, knitted and crocheted items, navatanee pasma, such as cloth, nonwoven cloth or woven products, in the form of long fiber and short-fiber materials.

8. Prepregs under item 1, characterized in that the powdery polyurethane compositions generally contain a mixture of polymer (b) having functional groups reactive towards isocyanate groups, as binder and internally locked and/or blocked by blokiruyushchimi di - or MDI as a hardener (a).

9. Prepregs under item 8, characterized in that polymer (b) use polymers with hydroxyl groups, amino groups and mercaptopropanol, in particular polyesters, polyethers, polyacrylates, polycarbonates and/or polyurethanes with a hydroxyl number of from 20 to 500 mg KOH/g and an average molecular weight of from 250 to 6000 g/mol.

10. Prepregs under item 8, characterized in that the use of di - or polyisocyanates selected from the group comprising isophorondiisocyanate, hexamethylenediisocyanate, diisocyanatohexane, 2-methylpentadiene, 2,2,4-trimethyl-hexamethylenediisocyanate/2,4,4-trimethylhexamethylenediamine and/or norbornadiene, particularly preferably isophorondiisocyanate, hexamethylenediisocyanate, 2,2,4-trimethyl-hexamethylenediisocyanate/2,4,4-trimethylhexamethylenediamine and diisocyanatohexane, and you can also use isocyanurate.

11. Prepregs under item 8, characterized in that the external blocking agents selected from the group comprising ethylacetoacetate, Diisopropylamine, methylethylketoxime, diethyl ester of malonic acid, ε-caprolactam, 1,2,4-triazole, phenol or substituted phenols, and/or 3,5-dimethylpyrazol.

12. Prepregs under item 8, characterized in that the use of adducts of isophorondiisocyanate, which groups and blocked ε-ka is prolaktinom isocyanate structure.

13. Prepregs under item 1, characterized in that the powdery polyurethane compositions contain additional catalysts, preferably dilaurate dibutylamine, octoate zinc, neodecanoate bismuth, and/or tertiary amines, for example, preferably 1,4-diazabicyclo[2.2.2.]the octane number which comprises from 0.001 to 1% of the mass.

14. The application specified in paras.8-13 powdery polyurethane compositions for the manufacture of prepregs, preferably containing reinforcing fibers of glass, carbon or aramid fibers.

15. A method of manufacturing a prepreg according to one of paragraphs.1-13 by applying component B) to component a), preferably performed by the method of dispersion, and optionally fixing component C) preferably under the action of heat, particularly preferably by sintering.

16. The use of prepreg on one of the PP.1-13 for the manufacture of composite materials used in shipbuilding, including small shipbuilding, aviation and space technology, in the automotive industry, for two-wheeled vehicles, preferably motorcycles and bicycles in the areas of transport, construction, medical equipment and sports in the electrical and electronics industry, as well as for power plants, in particular, the blades of wind set the K.

17. A method of manufacturing parts made of composite material, the prepreg on one of the PP.1-13 at temperatures from 120°C to 200°C is pressed in a suitable form under pressure and optionally under vacuum.

18. Parts made of composite material containing prepregs obtained by the method according to p. 17.