EP0768406A1 - High density flat textile structure made of polyester hybrid yarns, process for producing composite materials and use of the flat textile structure - Google Patents

Abstract

Textile material contains hybrid yarn of polyester reinforcing fibres and low-melting polyester matrix fibres and has a density D > 0.6 g/cm<3>, in which D = the ratio of the mass/unit area in g/cm<2> and the thickness in cm. Also claimed is a method of making composites from this material.

Description

The present invention textile fabrics based on polyester with high density, which can be processed into composite materials with a very good integration of the reinforcing fibers in a polyester matrix.

Textile fabrics for the production of composite materials are already known. For example, GB-A-1,200,342 describes fabrics made of reinforcing fibers and matrix fibers that can be pressed into fiber-reinforced composite materials.

It is also already known to use hybrid yarns for the production of fiber-reinforced composite materials. JP-A-03-266,745 describes a flexible band of hybrid yarns which, in addition to a first filament yarn component, contains a matrix-forming elastomeric second filament yarn component. Such tapes are wound on a mandrel and by melting the second filament yarn component, a flexible molded body is produced which is suitable for use as an airbag. This manufacturing route bypasses the manufacture of a textile surface, such as a woven or knitted fabric.

From JP-A-04-146,235, fabrics and knitted fabrics are known which contain a hybrid yarn made of a multi-component fiber and a conventional polyester fiber. The multi-component fiber consists of a thermoplastic elastomer, such as an elastomeric polyurethane or an elastomeric polyester, and a polyester. The described Flat structures are intended for textile applications and are characterized by good elastic recovery and freedom from creasing. The fabrics are stabilized by melting the elastomer component during dyeing, and the result is a good distribution of the melted component in the fabric. This publication does not refer to the production of fiber-reinforced composite materials from these fabrics. The fields of application of the fabrics and knitted fabrics mentioned in this publication suggest that they must be fabrics with a relatively low density.

JP-A-04-353,525 discloses prepregs made of hybrid yarns which, in addition to reinforcing fibers, are made up of filaments made of thermoplastic and elastomeric materials. Polyester and polyurethane are mentioned as thermoplastic and elastomeric components. The prepregs are used to manufacture composite materials; For this purpose, hybrid yarns can be produced from the two types of filament, which are processed into fabrics and then converted into shaped structures by heating, or direct molding processes such as pultrusion or filament winding processes are used. Shaped structures with complicated shapes can be produced from the prepregs. The shaped structures are characterized by good damping properties, high flexibility and impact resistance and can be used as conveyor belts, shoe soles or sporting goods. This publication does not refer to the production of high-density textile fabrics.

Furthermore, from our older German patent application 19 531 001.2 scrims made of hybrid yarns are known which can be used as carriers for reinforcing nonwovens. The thread densities of the fabrics specifically described there are relatively high at up to 10 threads per centimeter.

There is still a need for textile fabrics containing reinforcing fibers and matrix fibers that are suitable for the production of fiber-reinforced composite materials.

There have now been found textile fabrics which are outstandingly suitable for this purpose and which can be processed into composite materials with good integration of the reinforcing fibers in the matrix. Furthermore, single-variety composite materials that can be easily recycled can be produced from the textile fabrics according to the invention.

The invention relates to textile fabrics containing hybrid yarns made of reinforcing fibers made of polyester and of lower melting matrix fibers made of polyester, and with a density D of greater than or equal to 0.6 g / cm ³ , preferably greater than or equal to 0.7 g / cm ³ , where D is the quotient the weight per unit area of the textile fabric, expressed in g / cm ² , and the thickness of the textile fabric, expressed in cm.

The term "textile fabric" is to be understood in its broadest meaning within the scope of this description. These can be all structures containing the hybrid yarns described above, which have been produced using a surface-forming technique and which have the density D defined above.

Examples of such textile fabrics are knitted fabrics, knitted fabrics, scrims and in particular fabrics.

The term "fiber" is also to be understood in its broadest meaning in the context of this description. This includes both fibers of limited length (staple fibers) and preferably continuous fibers, so-called filaments, which are in the form of multifilaments.

The term "hybrid yarn" is also to be understood in its broadest meaning in the context of this description. This means any combination containing reinforcing fibers and matrix fibers.

Examples of possible hybrid yarn types are filament yarns from different types of filaments which are interwoven with one another or combined with one another by means of another technology, such as for example twisting or interlacing; or combinations of filaments with staple fibers, for example so-called core yarns; or combinations of different types of staple fibers, for example so-called secondary spun yarns. All of these hybrid yarn types are characterized by the presence of two or more types of fibers, at least one type of fiber being a polyester reinforcing fiber and at least one type of fiber being a polyester matrix fiber.

Filament yarns are preferred; Hybrid yarns produced by intermingling or commingling techniques are particularly preferred.

The production of the hybrid yarns used in accordance with the invention is described using the example of the preferred blow-mixed yarns. Other types of hybrid yarns can be produced in a manner known per se.

The interlacing of the hybrid yarns made of reinforcing and matrix filaments can take place - in particular when using high-modulus polyester reinforcing filaments - by means of a special warm interlacing process, which is described in EP-B-0,455,193. Here, in order to avoid filament breaks during swirling, the filaments are warmed up to near the softening point before swirling. The heating can be carried out by means of godets and / or a heating tube, while the low-melting thermoplastic individual filaments of the matrix fiber made of polyester are fed to the superordinate intermingling nozzle without preheating. This smooth, with high Threaded hybrid yarns are easy to weave.

Furthermore, customary intermingling or commingling techniques can be used to produce the hybrid yarns, as described, for example, in chemical fibers / textile industry, (7/8) 1989, T 185-7.

The hybrid yarns used to produce the textile fabrics according to the invention contain matrix fibers made of thermoplastic polyesters which have a melting point which is usually at least 10 ° C., preferably at least 30 ° C. below the melting point of the polyester reinforcing fibers.

The textile fabrics according to the invention can be produced by means of techniques known per se, in particular by weaving or warp knitting techniques with their numerous variations, such as e.g. Weft rustling.

Depending on the intended use, the textile fabrics according to the invention can consist to a small extent or entirely of the hybrid yarns defined above. For example, in the case of textile fabrics made of several thread systems, it is possible to build up only one or some of these thread systems entirely or only partially from hybrid yarns. The proportion of the hybrid yarns to be selected in the individual case will be determined in addition to the desired application purpose by the respective proportion of the matrix fibers in the hybrid yarn. The proportion of hybrid yarns in the textile fabric or the proportion of matrix filaments in the hybrid yarn is selected according to the requirement profile of the processor.

In addition to the hybrid yarns defined above, some of the yarns that make up the textile fabrics can only consist of carrier fibers or only of binder fibers. The proportion of the hybrid yarns is to be chosen in any case so that their proportion in at least one of the thread systems making up the textile fabric is at least 10%, preferably at least 50%, very particularly preferably at least 95%.

The density of the textile fabrics according to the invention is at least 0.6 g / cm ³ . To determine the density, a) the basis weight of the textile fabric in g / cm ^{2 is} determined and b) the thickness of the textile fabric in cm. The basis weight of the textile fabrics according to the invention is determined in accordance with DIN 53 854; The thickness of the textile fabrics according to the invention is measured in accordance with DIN 53 855, part 1 (measuring area 10 cm ² ; measuring pressure 50 cN / cm ² ). The density D is determined by forming the quotient from the basis weight and the thickness of the textile fabric.

The upper limit of the density of the textile fabric is determined by the density of the polyester used; it is about 1.4 g / cm ³ in size. The density can be checked by adjusting the thread densities in the textile fabric accordingly.

Textile fabrics which have a density D in the range from 0.7 to 1.35 g / cm ³ are preferred.

Particularly preferred textile fabrics consist of at least 50% hybrid yarns which contain reinforcing fibers made of polyester and lower-melting matrix fibers made of polyester.

Textile fabrics containing hybrid filament yarns are particularly preferred.

Textile fabrics containing hybrid yarns with polyester reinforcing filaments which have an initial modulus of greater than 10 GPa are very particularly preferred.

Likewise preferred are textile fabrics which contain hybrid yarns with matrix fibers made of polyethylene terephthalate or in particular made of polybutylene terephthalate, which have a lower melting point than the reinforcing fibers.

Very particularly preferred are textile fabrics which contain hybrid yarns which in turn contain reinforcing fibers made of a liquid-crystalline polyester and lower-melting matrix fibers made of polyethylene terephthalate.

Furthermore, textile fabrics are particularly preferred which contain hybrid yarns which in turn contain reinforcing fibers made of polyethylene terephthalate with a specific strength of greater than or equal to 60 cN / tex and lower melting matrix fibers made of polybutylene terephthalate and / or of modified polyethylene terephthalate copolymers.

The textile fabrics according to the invention mainly contain polyester fibers as reinforcing fibers. Reinforcing fibers in the sense of this description mean fibers which assume a reinforcing function in the composite material to be produced from the textile fabric.

The individual fibers of the polyester reinforcing fibers usually have an initial modulus of more than 10 GPa. Reinforcing fibers are preferably made of high-strength and low-shrinkage polyester filaments, especially based on polyethylene terephthalate, which have a tenacity of greater than or equal to 60 cN / tex and a maximum tensile strength elongation of less than or equal to 25%, preferably from 8 to 25%, and a hot air shrinkage (measured at 200 ° C.) of less than or equal to 25%, preferably less than or equal to 15%.

Polyester reinforcing fibers consist, for example, of liquid crystalline polyesters (LCP), such as of poly (p-hydroxybenzoate), of polyethylene naphthalate or of copolyesters derived from 2,6-naphthalenedicarboxylic acid, terephthalic acid and ethylene glycol, or derived from 2,6-naphthalenedicarboxylic acid, 4. 4'-biphenyldicarboxylic acid, terephthalic acid and ethylene glycol, or in particular from polyethylene terephthalate.

In addition to polyester reinforcing fibers, the textile fabrics according to the invention can also contain a small proportion, for example up to 10% by weight, of other carrier fibers; Examples of this are fibers with an initial modulus of more than 50 GPa, such as fibers made of glass, carbon or high-performance polymers (i.e. fibers which provide a very high initial modulus and a very high tensile strength with little or no stretching), such as polyolefins, e.g. Polyethylene (PE) or polypropylene (PP), and aramids, e.g. Poly- (p-phenylene-terephthalamide), or from organic solvents, such as N-methylpyrrolidone, spinnable aramides derived from terephthalic acid dichloride and a mixture of two or more aromatic diamines, for example the combination of p-phenylenediamine, 1,4-bis (4 -aminophenoxy) -benzene, 3,3'-dimethylbenzidine, or p-phenylenediamine, 1,4-bis (4-aminophenoxy) -benzene, 3,4'-diaminodiphenyl ether, or p-phenylenediamine, m-phenylenediamine, 1, 4-bis (4-aminophenoxy) benzene.

Matrix fibers in the hybrid yarns used according to the invention consist of or contain thermoplastic polyester. This can be any melt-spinnable polyester, as long as the fibers made from it melt at a lower temperature than the melt or Decomposition temperature of the reinforcing fibers used in each case is.

One and the same polyester fiber can be used as a reinforcing fiber or as a matrix fiber, depending on the raw material combination chosen in the individual case. For example, hybrid yarns made from high-melting liquid-crystalline polyesters can be used as reinforcing fibers and from polyethylene terephthalate fibers as matrix fibers; but also hybrid yarns made from polyethylene terephthalate fibers as reinforcing fibers and from lower melting modified polyethylene terephthalate fibers as matrix fibers.

Matrix fibers made from a thermoplastic modified polyester, in particular from a modified polyethylene terephthalate, are preferably used, the modification causing a lowering of the melting point in comparison with the fiber made from unmodified polyethylene terephthalate.

Ar¹

einen zweiwertigen ein- oder mehrkernigen aromatischen Rest darstellt, dessen freie Valenzen sich in para-Stellung oder in einer zu dieser Stellung vergleichbaren parallelen oder koaxialen Stellung zueinander befinden, vorzugsweise 1,4-Phenylen und/oder 2,6-Naphthylen darstellt,

R¹ und R³

unabhängig voneinander zweiwertige aliphatische oder cycloaliphatischen Reste darstellen, insbesondere Reste der Formel -C_nH_2n-, worin n eine ganze Zahl zwischen 2 und 6 ist, insbesondere Ethylen, oder einen von Cyclohexandimethanol abgeleiteten Rest darstellen, und

R²

einen zweiwertigen aliphatischen, cycloaliphatischen oder ein- oder mehrkernigen aromatischen Rest darstellt, dessen freie Valenzen sich in meta-Stellung oder in einer zu dieser Stellung vergleichbaren gewinkelten Stellung zueinander befinden, vorzugsweise 1,3-Phenylen darstellt.

Modified polyesters of this type particularly preferably contain the recurring structural units of the formulas I and II

-O-OC-Ar ¹ -CO-OR ¹ - (I), and



-O-OC-R ² -CO-OR ³ - (II),

wherein

Ar ¹

represents a divalent mono- or polynuclear aromatic radical, the free valences of which are in the para position or in a parallel or coaxial position with respect to one another, preferably 1,4-phenylene and / or 2,6-naphthylene,

R ¹ and R ³

independently represent divalent aliphatic or cycloaliphatic radicals, in particular radicals of the formula -C _n H _2n -, in which n is an integer between 2 and 6, in particular ethylene, or a radical derived from cyclohexanedimethanol, and

R ²

represents a divalent aliphatic, cycloaliphatic or mononuclear or polynuclear aromatic radical, the free valences of which are in the meta position or in an angled position comparable to this position, preferably 1,3-phenylene.

Very particularly preferred modified polyesters of this type contain 40 to 95 mol% of the repeating structural units of the formula I and 60 to 5 mol% of the repeating structural units of the formula II; Ar ^{1 is} 1,4-phenylene and / or 2,6-naphthylene, R ¹ and R ^{3 are} ethylene and R ^{2 is} 1,3-phenylene.

In a further preferred embodiment, matrix fibers are used which consist of or contain a thermoplastic and elastomeric polyester. This can also be any melt-spinnable and elastomeric polyester, as long as the fibers produced from it melt at a lower temperature than the melting or decomposition temperature of the reinforcing fiber used in the respective case.

In the context of this description, “elastomeric polyester” is understood to mean a polyester whose glass transition temperature is less than 23 ° C., preferably less than 0 ° C., in particular -50 to 0 ° C.

Ar² und Ar³

unabhängig voneinander zweiwertige aromatische Reste darstellen,

R⁴

einen zweiwertigen aliphatischen oder cycloaliphatischen Rest darstellt, und

R⁵

den zweiwertigen Rest eines Polyalkylenethers bedeutet.

Hybrid yarns are particularly preferably used which contain matrix fibers made of thermoplastic and elastomeric polyester which contains the recurring structural units of the formulas III and IV

-O-OC-Ar ² -CO-OR ⁴ - (III), and



-O-OC-Ar ³ -CO-OR ⁵ - (IV),

wherein

Ar ² and Ar ³

independently represent divalent aromatic radicals,

R ⁴

represents a divalent aliphatic or cycloaliphatic radical, and

R ⁵

means the divalent radical of a polyalkylene ether.

Ar ² and Ar ^{3 are} preferably independently of one another a phenylene and / or a naphthylene radical.

Ar ² and Ar ³ each particularly preferably denote 1,4-phenylene.

R ⁴ as a divalent aliphatic radical means straight-chain or branched alkylene or alkylidene; these are usually residues with two to twenty carbon atoms, preferably two to eight carbon atoms and in particular two to four carbon atoms.

R ⁴ is particularly preferably straight-chain alkylene having two to six carbon atoms, in particular ethylene.

R ⁴ as a divalent cycloaliphatic radical usually means a radical containing five to eight, preferably six ring carbon atoms; this carbocycle is particularly preferably part of an aliphatic chain. An example of a particularly preferred representative of this type is the rest of the cyclohexanedimethanol.

R ⁴ is particularly preferably a radical of the formula -C _n H _2n -, in which n is an integer between 2 and 6 or a radical derived from cyclohexanedimethanol.

R ⁵ as a divalent radical of a polyoxyalkylene usually means a polyether radical which has recurring oxyethylene, oxypropylene or in particular oxybutylene units or mixtures of these units.

o

eine ganze Zahl von zwei bis vier bedeutet und z eine ganze Zahl von 1 bis 50 ist.

R ⁵ particularly preferably represents a radical of the formula V.

- [C _o H _2o -O] _z -C _o H _2o - (V),

wherein

O

is an integer from two to four and z is an integer from 1 to 50.

Most preferably o is four and z is an integer from 10 to 18.

Hybrid yarns made of thermoplastic and elastomeric polyester containing the recurring structural units of the formulas III and IV defined above are particularly preferred, wherein Ar ² and Ar ^{3 are} 1,4-phenylene, R ^{4 is} ethylene, R ^{5 is} a group of the formula V defined above is o is four, and in which the proportion of the recurring structural units of the formula V, based on the proportion of the polyester molecule, is 5 to 60% by weight.

Fibers made of such polyesters have different melting points depending on the proportion of the repeating structural units of the formula V; the higher the proportion of these structural units, the lower the melting point can be set. For example, fibers made of an elastomeric polyester of this type with a content of 13% by weight of polyoxybutylene have a melting point of about 220 ° C., while fibers made of an elastomeric polyester of this type with a content of 53% by weight of polyoxybutylene have a melting point of about 160 ° C.

If any radicals in the structural formulas defined above mean divalent aliphatic radicals, this means branched and in particular straight-chain alkylene, for example alkylene with two to twenty, preferably with two to eight, carbon atoms. Examples of such radicals are ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl or octane-1,8 -diyl.

If any radicals in the structural formulas defined above are divalent cycloaliphatic radicals, they are to be understood as meaning groups which contain carbocyclic radicals having five to eight, preferably six, ring carbon atoms. Examples of such radicals are cyclohexane-1,4-diyl or the group -CH ₂ -C ₆ H ₁₀ -CH ₂ -.

If any radicals in the structural formulas defined above mean divalent aromatic radicals, these are mono- or polynuclear aromatic hydrocarbon radicals or heterocyclic-aromatic radicals which can be mono- or polynuclear. In the case of heterocyclic-aromatic radicals, these have in particular one or two oxygen, nitrogen or sulfur atoms in the aromatic nucleus.

Polynuclear aromatic radicals can be condensed with one another or connected to one another via C-C bonds or via bridging groups such as -O-, -S-, -CO- or -CO-NH groups.

The valence bonds of the divalent aromatic radicals can be in a para- or in a comparable coaxial or parallel position to one another, or also in a meta or in a comparable angular position to one another.

The valence bonds, which are in a coaxial or parallel position, are directed in opposite directions. An example of coaxial, oppositely directed bonds are the biphen-4,4'-diyl bonds. On Examples of parallel, opposite bonds are the naphthalene 1,5 or 2,6 bonds, while the naphthalene 1,8 bonds are parallel aligned.

Examples of preferred divalent aromatic radicals whose valence bonds are in para- or in a comparable coaxial or parallel position to one another are mononuclear aromatic radicals with mutually para-free valences, in particular 1,4-phenylene or dinuclear fused aromatic radicals with parallel directed bonds, in particular 1,4-, 1,5- and 2,6-naphthylene, or dinuclear aromatic residues linked via a CC bond with coaxial, oppositely directed bonds, in particular 4,4'-biphenylene.

Examples of preferred divalent aromatic radicals whose valence bonds are in a meta or in a comparable angled position to one another are mononuclear aromatic radicals with free valences which are meta to one another, in particular 1,3-phenylene or dinuclear condensed aromatic radicals with bonds oriented at an angle to one another, in particular 1,6- and 2,7-naphthylene, or dinuclear aromatic residues linked via a CC bond with bonds oriented at an angle to one another, in particular 3,4'-biphenylene.

If any radicals mean divalent araliphatic radicals, they are to be understood as meaning groups which contain one or more divalent aromatic radicals which are combined with an alkylene radical via one or both valences. A preferred example of such a radical is the group -C ₆ H ₄ -CH ₂ -.

The recurring structural units of the formula III or IV are typical hard or soft segments. Thermoplastic polyesters of this type are known and are used, for example, in Domininghaus: "Die Plastics and their properties ", 3rd edition, VDI Verlag GmbH, Düsseldorf 1988, pp. 518 - 524.

All of these aliphatic, cycloaliphatic, aromatic, araliphatic or polyoxyalkylene radicals can be substituted with inert groups. These are to be understood as substituents that do not negatively influence the envisaged application.

Examples of such substituents are alkyl, alkoxy or halogen.

Alkyl radicals are to be understood as meaning branched and in particular straight-chain alkyl, for example alkyl having one to six carbon atoms, in particular methyl.

Alkoxy radicals are to be understood as meaning branched and in particular straight-chain alkoxy, for example alkoxy with one to six carbon atoms, in particular methoxy.

If any radicals are halogen, it is, for example, fluorine, bromine or, in particular, chlorine.

The matrix fibers used in the hybrid yarn used according to the invention can be constructed from thermoplastic polyesters which usually have an intrinsic viscosity of at least 0.5 dl / g, preferably 0.6 to 1.5 dl / g. The intrinsic viscosity is measured in a solution of the thermoplastic polymer in dichloroacetic acid at 25 ° C.

The reinforcing fibers made of polyester used in the hybrid yarn used according to the invention usually have an intrinsic viscosity of at least 0.5 dl / g, preferably 0.6 to 1.5 dl / g. The intrinsic viscosity is measured as described above.

The hybrid yarns used according to the invention usually have yarn titer of 2000 to 150 dtex, preferably 1100 to 150 dtex.

The individual fiber titer of the reinforcing fibers and the matrix fibers usually ranges from 2 to 10 dtex, preferably 2 to 6 dtex.

The cross sections of the reinforcing fibers and the matrix fibers can be any; for example elliptical, bi- or multilobal, ribbon-shaped or preferably round.

The thermoplastic polymers are prepared by processes known per se by polycondensation of the corresponding bifunctional monomer components; usually dicarboxylic acids or dicarboxylic acid esters and the corresponding diol components are used. Such thermoplastic and optionally elastomeric polyesters are already known.

The reinforcing fibers used in the textile fabrics according to the invention are also known per se.

The mechanical properties of the hybrid yarns used according to the invention can be varied within wide limits depending on the composition, such as the type and proportion of the reinforcing fibers or the matrix fibers, depending on the physical structure of the yarn, such as the degree of intermingling. The proportion of the matrix fibers is usually 10 to 50% by weight, based on the weight of the hybrid yarn.

The textile fabrics according to the invention can be processed in a simple manner by using elevated temperatures, if appropriate using pressure, to give fiber-reinforced composite materials with very good embedding of the reinforcing fibers in the matrix, which are distinguished by high energy absorption and high strength. It can also be used to produce flat structures with selectively adjustable gas and / or liquid permeability.

• a) Herstellen von textilen Flächengebilden enthaltend Hybridgarne aus Verstärkungsfasern aus Polyester und aus niedriger schmelzenden Matrixfasern aus Polyester gemäß der oben gegebenen Definition nach an sich bekannten Flächenbildungstechniken,
• b) gegebenenfalls Konfektionieren der in Schritt a) hergestellten textilen Flächengebilde,
• c) gegebenenfalls Aufeinanderstapeln der in Schritt b) hergestellten textilen Flächengebilde gegebenenfalls zusammen mit konfektionierten textilen Flächengebilden enthaltend Träger- und/oder niedriger schmelzende Bindefasern mit einer von der oben gegebenen Definition abweichenden Definition, und
• d) Verpressen des in Schritt a) hergestellten textilen Flächengebildes gegebenfalls zusammen mit weiteren textilen Flächengebilden enthaltend Trägerund/oder niedriger schmelzende Bindefasern mit einer von der oben gegebenen Definition abweichenden Definition, oder Verpressen des in Schritt c) hergestellten Stapels unter Anwendung von erhöhter Temperatur, so daß die niedriger schmelzenden Matrix- bzw. Bindefasern aufschmelzen und die Verstärkungs- bzw. Trägerfasern unter Ausbildung einer Matrix einbetten.

The invention also relates to a method for producing composite materials containing polyester reinforcing fibers and a matrix made of polyester, comprising the measures:

• a) Manufacture of textile fabrics containing hybrid yarns from reinforcing fibers made of polyester and from lower-melting matrix fibers made of polyester according to the definition given above according to known fabric formation techniques,
• b) if appropriate, assembling the textile fabrics produced in step a),
• c) optionally stacking the textile fabrics produced in step b) together, if appropriate, together with ready-made textile fabrics containing carrier and / or lower-melting binder fibers with a definition deviating from the definition given above, and
• d) pressing the textile fabric produced in step a) optionally together with further textile fabrics containing carrier and / or lower melting binder fibers with a definition deviating from the definition given above, or pressing the stack produced in step c) using increased Temperature so that the lower melting matrix or binder fibers melt and embed the reinforcement or carrier fibers to form a matrix.

The textile fabrics according to the invention can be further processed either continuously or batchwise.

An example of a continuous mode of operation is the pressing of the textile fabrics according to the invention after their production, optionally together with additional webs of textile fabrics containing carrier and / or binding fibers or containing other web material, such as films made of thermoplastic polymers.

In this variant, the pressing is preferably carried out by calendering or by using a double belt press.

An example of a discontinuous method of operation is the pressing of the textile fabrics according to the invention after they have been assembled, optionally together with additional assembled textile fabrics containing carrier and / or binding fibers or derived from another sheet material, such as from the above-mentioned films made of thermoplastic polymers.

In this variant, the pressing is preferably carried out in a deck press. The processing temperature in step d) is to be chosen so that the matrix or binding component melts and that this component has a melt viscosity of less than or equal to 1000 Pa * sec. Typical compression pressures are up to 50 N / mm ² .

The matrix component in the composite materials produced according to the invention can only make up a small proportion, for example 3% by weight, based on the weight of the composite material; however, the matrix component can also make up a high proportion, for example more than 70% by weight, based on the weight of the composite material, preferably 3 to 50% by weight.

The composite materials produced according to the invention can be used in a large number of fields of application, for example as protective clothing, such as rain clothing, chemical protective clothing or diving clothing; as tent fabrics or tent floors; as linings for containers, such as silo, pool or container linings; as bags; as materials for making shoes; as maritime textiles, such as textiles for the manufacture of inflatable boats, life jackets or life rafts; as a textile building material; as a carrier material, such as a material for producing light conveyor belts; as geotextiles; for use in hydraulic engineering, such as rain catch tanks or landfill covers; as sails or tarpaulin or for the production of airbags.

Another object of the present invention is the use of the textile fabrics according to the invention for the production of composite materials.

The following example explains the invention without limiting it.

Example:

A L1 / 1 plain weave fabric with 7.5 threads / cm in the warp and 7.5 threads / cm in the weft was produced on a Dornier rapier weaving machine.

Warp and weft consisted of hybrid yarns with a yarn denier of 1790 dtex containing high-strength filaments made of polyethylene terephthalate as reinforcing component and filaments made of isophthalic acid-modified polyethylene terephthalate as matrix component; wherein the proportion of repeating isophthalic acid units in the copolyester was 33 mol%, based on the total amount of dicarboxylic acid components. The proportion of the matrix component in the hybrid yarn was 38% by weight.

The fabric was washed at 30 ° C after manufacture.

Then several layers of this fabric were pressed into laminates of different thicknesses, the orientation of the layers being chosen chain by chain. Laminates with 1 mm thickness (from 5 layers of the fabric), with 2 mm thickness (from 11 layers of the fabric) and with 4 mm thickness (from 22 layers of the fabric) were produced. The 1 mm thick laminate was used for tensile tests, the 2 mm thick laminate for bending tests and the 4 mm thick laminate for impact strength tests. The laminates were pressed in a heated press at a pressing temperature of 180 ° C. and a pressure of 12 N / mm ² . mechanical properties: Flexural strength (warp direction; DIN 29971): 97 N / mm ² Bending module (warp direction; DIN 29971): 4.2 kN / mm ² Flexural strength (weft direction; DIN 29971): 116 N / mm ² Bending module (weft direction; DIN 29971): 4.7 kN / mm ² Interlaminan shear strength (warp direction; DIN 29971): 22 N / mm ² Interlamin shear strength (weft direction; DIN 29971): 19 N / mm ² Tensile strength (warp direction; DIN 29971): 230 N / mm ² Tension module (warp direction; DIN 29971): 1.1 kN / mm ² Impact resistance (ISO 179; Charpy 23 ° C): 213 mJ / mm ² (15 J pendulum hammer; 10 of 10 samples partially broken) Impact resistance (ISO 180 / 1C; Izod 23 ° C): 10 out of 10 without break Impact resistance (ISO 180 / 1C, Izod -30 ° C): 10 out of 10 without break Heat resistance: Dimensional stability in heat (ISO 75; HDT / A): 95 ° C Dimensional stability in heat (ISO 75; HTD / B): 132 ° C Softening temperature (ISO 305; Vicat B / 50): 104 ° C

Claims (16)

Textile fabrics containing hybrid yarns made of reinforcing fibers made of polyester and of lower melting matrix fibers made of polyester, and with a density D greater than or equal to 0.6 g / cm ³ , where D is the quotient of the weight per unit area of the textile fabric, expressed in g / cm ² , and the thickness of the fabric, expressed in cm. Textile fabrics according to claim 1, characterized in that they have a density D in the range from 0.7 to 1.35 g / cm ³ . Textile fabrics according to claim 1, characterized in that they are a knitted fabric, a knitted fabric, a woven fabric or a scrim. Textile fabrics according to claim 1, characterized in that these consist of at least 50% hybrid yarns containing reinforcing fibers made of polyester and lower melting matrix fibers made of polyester. Textile fabrics according to claim 1, characterized in that the hybrid yarns are filament yarns. Textile fabrics according to claim 1, characterized in that the hybrid yarns contain reinforcing filaments which have an initial modulus of greater than 10 GPa and consist of polyester, in particular of polyethylene terephthalate. Textile fabrics according to claim 1, characterized in that the hybrid yarns contain lower melting matrix fibers of polyethylene terephthalate or in particular of polybutylene terephthalate. Textile fabrics according to claim 1, characterized in that the hybrid yarns contain reinforcing fibers made of a liquid crystalline polyester and lower melting matrix fibers made of polyethylene terephthalate. Textile fabrics according to claim 1, characterized in that the hybrid yarns contain reinforcing fibers made of polyethylene terephthalate with a specific strength of greater than or equal to 60 cN / tex and lower melting matrix fibers made of polybutylene terephthalate and / or of modified polyethylene terephthalate copolymers. Textile fabrics according to claim 1, characterized in that the hybrid yarns contain lower melting matrix fibers made from a modified polyethylene terephthalate containing the recurring structural units of the formulas I and II

-O-OC-Ar ¹ -CO-OR ¹ - (I), and



-O-OC-R ² -CO-OR ³ - (II),

wherein Ar ^{1 represents} a divalent mono- or polynuclear aromatic radical, the free valences of which are in the para position or in a parallel or coaxial position with respect to one another, preferably 1,4-phenylene and / or 2,6-naphthylene, R ¹ and R ³ independently of one another represent divalent aliphatic or cycloaliphatic radicals, in particular radicals of the formula - -C _n H _2n -, in which n is an integer between 2 and 6, in particular ethylene, or a radical derived from cyclohexanedimethanol, and R ^{2 represents} a divalent aliphatic, cycloaliphatic or mononuclear or polynuclear aromatic radical, the free valences of which are in the meta position or in an angled position comparable to this position, preferably 1,3-phenylene. Textile fabrics according to claim 10, characterized in that the hybrid yarns contain matrix filaments made from a modified polyethylene terephthalate which contains 40 to 95 mol% of the repeating structural units of the formula I and 60 to 5 mol% of the repeating structural units of the formula II, in which Ar ^{1 is} 1,4-phenylene and / or 2,6-naphthylene, R ¹ and R ^{3 are} ethylene and R ^{2 is} 1,3-phenylene. Textile fabrics according to claim 1, characterized in that the hybrid yarns contain matrix fibers made of a thermoplastic and elastomeric polyester. Textile fabrics according to claim 12, characterized in that the thermoplastic and elastomeric polyester contains the recurring structural units of the formulas III and IV

-O-OC-Ar ² -CO-OR ⁴ - (III), and



-O-OC-Ar ³ -CO-OR ⁵ - (IV),

wherein Ar ² and Ar ³ independently of one another represent divalent aromatic radicals, preferably phenylene and / or naphthylene radicals, in particular 1,4-phenylene, R ^{4 represents} a divalent aliphatic or cycloaliphatic radical, in particular a radical of the formula -C _m H _2m -, in which m is an integer between 2 and 6 or a radical derived from cyclohexanedimethanol, in particular ethylene, and R ^{5 represents} the divalent radical of a polyalkylene ether, preferably represents a radical of the formula V.

- [C _o H _2o -O] _z -C _o H _2o - (V),

wherein o denotes an integer from two to four, in particular four, and z is an integer from 1 to 50, in particular an integer from 10 to 18. Textile fabrics according to Claim 13, characterized in that Ar ² and Ar ^{3 are} 1,4-phenylene, R ^{4 is} ethylene, o is four, and in which the proportion of the repeating structural units of the formula V, based on the proportion of the polyester molecule 5 to Is 60% by weight. Process for the production of composite materials containing polyester reinforcing fibers and a matrix of polyester comprising the measures: a) Manufacture of textile fabrics containing hybrid yarns from reinforcing fibers made of polyester and from lower-melting matrix fibers made of polyester according to claim 1 according to known fabric formation techniques, b) if appropriate, assembling the textile fabrics produced in step a), c) optionally stacking the textile fabrics produced in step b), if appropriate together with ready-made textile fabrics containing carrier and / or lower-melting binder fibers with a definition deviating from claim 1, and d) pressing the textile fabric produced in step a) together with further textile fabrics containing carrier and / or lower melting binder fibers with a definition deviating from the definition given above, or pressing the stack produced in step c) using an elevated temperature, if necessary that the lower melting matrix or binder fibers melt and embed the reinforcement or carrier fibers to form a matrix. Use of the textile fabrics according to claim 1 for the production of composite materials.