DE102010042131A1 - Fiber-reinforced rubber body, preferably vehicle tires, conveyor belt or gear box belt comprises matrix made of vulcanized rubber and fibers embedded in the matrix - Google Patents

Abstract

Fiber-reinforced rubber body, preferably vehicle tires, conveyor belt or transmission belt comprises a matrix made of vulcanized rubber and fibers embedded in the matrix. The fiber material comprises at least a copolyamide (30 wt.%), which is derived from (a) a mixture of diamine (50-95 mol.%) comprising 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine or 1,12-dodecanediamine and terephthalic acid, and (b) a mixture of diamine (5-50 mol.%) comprising 2,2,4-trimethyl hexamethylene diamine and/or 2,4,4-trimethyl hexamethylene diamine and terephthalic acid. Fiber-reinforced rubber body, preferably vehicle tires, conveyor belt or transmission belt comprises a matrix made of vulcanized rubber and fibers embedded in the matrix. The fiber material comprises at least a copolyamide (30 wt.%), which is derived from (a) a mixture of diamine (50-95 mol.%) comprising 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine or 1,12-dodecanediamine and terephthalic acid, and (b) a mixture of diamine (5-50 mol.%) comprising 2,2,4-trimethyl hexamethylene diamine and/or 2,4,4-trimethyl hexamethylene diamine and terephthalic acid, where the specified mole-% is based on the sum of components (a) and (b).

Description

The invention relates to a fiber-reinforced rubber body, in particular a vehicle tire, a conveyor belt or a transmission belt, comprising a matrix of vulcanized rubber and fibers embedded in the matrix.

By "rubber" is commonly meant a material made of vulcanized synthetic and / or natural rubber. The properties of the rubber can be adjusted by fillers such as carbon black, talc or silica to the desired application. Rubber is viscoelastic, vibration-damping and seal-resistant, so that wear parts that are subject to dynamic loading, such as vehicle tires, conveyor belts or belts of traction drives, are often made of rubber.

If a rubber component is subjected to great mechanical stress, it is reinforced with fibers or wire. For this purpose, fibers are usually combined to form a textile fabric (called fiber cord, or fiber), added with the fresh rubber in the mold and vulcanized. This gives a fiber-reinforced rubber body with a wear-resistant rubber matrix and embedded therein, load-bearing chamfers, which significantly increase in particular the tensile strength of the rubber body. The fiber thus acts as the strength carrier in the rubber body.

The most widely used fiber-reinforced rubber bodies are car tires. As a textile reinforcement, they include a carcass vulcanized into the rubber matrix and, under the tread, belts of steel, nylon, PET, rayon or aramid. Steel fibers are inexpensive and have a constant tensile strength, high stiffness and good rubber adhesion. Nylon is lightweight and has a good price / strength ratio. PET is reasonably priced and has good rubber adhesion; the temperature resistance is not quite as good. Rayon is characterized by its high temperature stability. Aramid fibers have excellent tensile strength and are very temperature stable, but rubber adhesion is rather low. Due to their material-specific advantages and disadvantages, complex-loaded rubber bodies are reinforced with fibers of different fiber materials, so the load-bearing carcass of a tire is usually made of rayon, the belt at high speeds under the tread, however, made of steel or hybrid textile cords.

The fuel consumption of a vehicle can be lowered by reducing the rolling resistance of the tires. This has largely been done by using silica as an additive. Further fuel savings are possible by reducing the tire weight, which also has a positive effect on ride comfort. The introduced in the middle of the last century radial tires have a steel carcass, which significantly reduced the rolling resistance compared to the previously used bias tires. In return, the steel carcass increased the weight of the tires. Today synthetic fibers partially replace steel fibers in the tire and are used in three areas of radial tires: predominantly within the carcass, to a lesser extent in the belt and almost entirely in the bead adjacent the rim. Depending on the location of the fibers different fiber strengths are required, the fibers in the carcass of a car tire should have a tensile strength of 200 to 400 MPa, the cross layers 400 to 1000 MPa, the straps in the direction should consist of fibers whose tensile strength between 150 and 250 MPa.

In particular, the specific tensile strength is an important material parameter for the lightweight construction of tires. It is defined as the ratio of the tensile strength to the fiber fineness. The tensile strength is the force at which the fiber breaks; the fiber fineness the ratio of weight to the length of the fiber. The specific tensile strength is a measure of the conductive density of the material. The use of a fiber with a high specific tensile strength allows lighter tire designs with a low rubber content. A fiber material that promises very high specific tensile strengths is polyphthalamide.

Polyphthalamide (PPA) is an aromatic polyamide (aramid) polymerized from diamines and terephthalic acid.

Out WO 2007/092226 A2 is a fiber-reinforced rubber body in the form of a tube known. The inner wall of the rubber hose is lined with a layer of PPA, called fiber material polyamides or aromatic polyamides; PPA as a fiber material is not mentioned.

Out WO 1996/20842 A1 the use of PPA in vehicle wheels is known; However, not as a fiber material in the tire, but as a coating designed as an emergency running area of the rim. Contact with rubber is not provided here.

Out WO 1995/08011 A1 are melt-spun PPA-containing fibers known that are high temperature resistant by copper addition. For most applications in rubber, the temperature ranges achieved there are hardly relevant. For example, operating temperatures of only 80 ° C are to be expected for car tires. Although the fiber material must withstand the vulcanization temperature between 140 and 160 ° C, but this is done without mechanical stress, so that the tensile strength of the fiber at these temperatures must not be fully guaranteed.

In view of this prior art, the invention is based on the object, a fiber-reinforced rubber body of the type mentioned in such a way that its specific mechanical strength is increased over a wide temperature profile.

The task is solved by the use of a. Fiber material, as laid down in the characterizing part of claim 1.

• a) Zu 50 bis 95 Mol-% von der Kombination aus einem Diamin, ausgewählt aus der Gruppe 1,9-Nonandiamin, 1,10-Decandiamin, 1,11-Undecandiamin und 1,12-Dodecandiamin, sowie Terephthalsäure, und
• b) zu 5 bis 50 Mol-% von der Kombination aus einem Diamin, ausgewählt aus der Gruppe 2,2,4-Trimethylhexamethylendiamin, 2,4,4-Trimethylhexamethylendiamin und Mischungen hiervon, sowie Terephthalsäure,

wobei sich die angegebenen Mol-% auf die Summe der Komponenten a) und b) beziehen.The invention therefore provides a fiber-reinforced rubber body comprising a matrix of vulcanized rubber and fibers embedded in the matrix, the fiber material containing at least 30% by weight of a copolyamide derived from the following monomers:

• a) to 50 to 95 mol% of the combination of a diamine selected from the group 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine and 1,12-dodecanediamine, and terephthalic acid, and
• b) from 5 to 50 mol% of the combination of a diamine selected from the group consisting of 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine and mixtures thereof, and terephthalic acid,

where the stated mol% refer to the sum of components a) and b).

The fiber material used according to the invention is a polyphthalamide from which fibers with a very high specific tensile strength up to about 1.5 N / tex can be produced. In addition, these fibers have a good temperature stability (glass transition temperature T _g 140 to 150 ° C, melt temperature T _m 335 to 365 ° C) so that the fiber survives unscathed in the vulcanization and at use temperature of the rubber body of below 100 ° C still a large distance to the glass transition temperature at which the mechanical strength begins to decrease. Incidentally, the fiber material used according to the invention is characterized by good adhesion to conventionally used synthetic rubbers.

Thus, the fiber material according to the invention allows the design of lightweight, yet stable rubber bodies.

In a preferred embodiment, the copolyamide contains no building blocks derived from other monomers. In other embodiments, the copolyamide contains a maximum of 30 mol%, a maximum of 25 mol%, a maximum of 20 mol%, a maximum of 15 mol%, a maximum of 10 mol% or a maximum of 5 mol% of building blocks derived from further monomers , It should be noted that in this case diamine and dicarboxylic acid as well as any lactam or aminocarboxylic acid, if any, are counted individually in the calculation of the composition.

In addition, 0 to 70% by weight, preferably 0 to 60% by weight, more preferably 0 to 50% by weight and especially preferably 0.1 to 40% by weight of additives can be present based on the fiber material. The fiber material can therefore also consist of the pure copolyamide.

• – Entweder leiten sie sich von der Kombination eines Diamins und einer Dicarbonsäure her. Hier sind folgende Fälle zu unterscheiden:
• a) Die Dicarbonsäure ist Terephthalsäure; das Diamin ist ein anderes als eines der anspruchsgemäßen Diamine 1,9-Nonandiamin, 1,10-Decandiamin, 1,11-Undecandiamin, 1,12-Decandiamin, 2,2,4-TMD und 2,4,4-TMD.
• b) Die Dicarbonsäure ist eine andere als Terephthalsäure; das Diamin ist eines der eben angeführten anspruchsgemäßen Diamine.
• c) Sowohl die Dicarbonsäure ist eine andere als Terephthalsäure als auch das Diamin ist ein anderes als eines der eben angeführten anspruchsgemäßen Diamine.
• – Oder sie leiten sich von einem Lactam oder einer Aminocarbonsäure her.

The building blocks, which are derived from other monomers, fall into the following categories:

• - Either they are derived from the combination of a diamine and a dicarboxylic acid. Here are the following cases:
• a) The dicarboxylic acid is terephthalic acid; the diamine is other than one of the claimed diamines 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-decanediamine, 2,2,4-TMD and 2,4,4-TMD.
• b) The dicarboxylic acid is other than terephthalic acid; The diamine is one of the just mentioned diamines.
• c) Both the dicarboxylic acid is other than terephthalic acid and the diamine is other than one of the above-mentioned claimed diamines.
• - Or they are derived from a lactam or an aminocarboxylic acid.

Suitable other diamines are for example diamines having 4 to 22 carbon atoms, such as 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,8-octanediamine, 1,14-tetradecanediamine, 1,18-octadecanediamine , 2-methyl-1,5-diaminopentane, 2,2-dimethyl-1,5-diaminopentane, 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 3,3 ', 5 , 5'-Tetramethyl-4,4'-diaminodicyclohexylmethane, m- or p-xylylenediamine or isophoronediamine.

Suitable other dicarboxylic acids are, for example, dicarboxylic acids having 6 to 22 C atoms, for example adipic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, 2,2,4- or 2,4,4-trimethylhexanedioic acid, Isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid or 2-methyl-1,4-cyclohexanedicarboxylic acid.

Suitable lactams or aminocarboxylic acids are, for example, caprolactam, laurolactam or .omega.-aminoundecanoic acid.

Mixtures of other diamines, mixtures of other dicarboxylic acids, mixtures of lactams or aminocarboxylic acids and mixtures of other diamine or other dicarboxylic acid and lactam or aminocarboxylic acid can also be used here.

The copolyamide is usually prepared by melt polycondensation. Corresponding methods are state of the art. Alternatively, however, any other known polyamide synthesis method may be used.

• a) Andere Polymere;
• b) faserförmige Verstärkungsstoffe;
• c) Füllstoffe;
• d) Weichmacher;
• e) Pigmente und/oder Farbstoffe;
• f) Flammschutzmittel;
• g) Verarbeitungshilfsmittel und
• h) Stabilisatoren, insbesondere thermische Stabilistatoren.

Suitable additives in the fiber material are, for example:

• a) other polymers;
• b) fibrous reinforcing materials;
• c) fillers;
• d) plasticizer;
• e) pigments and / or dyes;
• f) flame retardants;
• g) processing aids and
• h) stabilizers, in particular thermal stabilizers.

Other polymers are, for example, polyamides, polyphenylene ethers and / or impact modifiers.

Suitable polyamides are, for example, PA46, PA66, PA68, PA610, PA612, PA613, PA410, PA412, PA810; PA1010, PA1012, PA1013, PA1014, PA1018, PA1212, PA6, PA11 and PA12 and copolyamides derived from these types. In principle, it is also possible to use partially crystalline aromatic polyamides, for example PA6T / 6I, PA6T / 66, PA6T / 6 or PA6T / 6I / 66.

Suitable polyphenylene ethers are prepared by conventional methods from ortho-position disubstituted by alkyl groups phenols by oxidative coupling. A particularly preferred polyphenylene ether is poly (2,6-dimethyl-1,4-phenylene) ether, optionally in combination with 2,3,6-trimethylphenol units. According to the prior art, the polyphenylene ether contains functional groups for attachment to the polyamide matrix; these functional groups are introduced, for example, by treatment with maleic anhydride.

Suitable impact modifiers are, for example, olefinic polymers containing functional groups grafted onto either the olefinic backbone or copolymerized into the backbone; suitable types and combinations are for example in the EP 1 170 334 A2 disclosed. In addition, polyacrylate rubber or ionomers can also be used.

The fiber material preferably contains not more than 40% by weight, particularly preferably not more than 30% by weight and particularly preferably not more than 25% by weight, of other polymers.

Suitable fillers are, for example, talc, mica, silicate, quartz, graphite, molybdenum disulfide, titanium dioxide, wollastonite, kaolin, amorphous silicas, magnesium carbonate, chalk, lime, feldspar, barium sulfate, conductive carbon black, graphite fibrils, solid or hollow glass spheres or ground glass.

Plasticizers and their use in polyamides are known. A general overview of plasticizers that are suitable for polyamides can Gächter / Müller, Kunststoffadditive, C. Hanser Verlag, 2nd Edition, p. 296 be removed.

As plasticizers suitable, conventional compounds are, for. B. esters of p-hydroxybenzoic acid having 2 to 20 carbon atoms in the alcohol component or amides of arylsulfonic acids having 2 to 12 carbon atoms in the amine component, preferably amides of benzenesulfonic acid.

Suitable plasticizers include p-hydroxybenzoic acid ethyl ester, octyl p-hydroxybenzoate, i-hexadecyl p-hydroxybenzoate, n-octyltoluene sulfonamide, benzenesulfonic acid-n-butylamide or benzenesulfonic acid 2-ethylhexylamide.

Suitable pigments and / or dyes are, for example, carbon black, iron oxide, zinc sulfide, ultramarine, nigrosine, pearlescent pigments and metal flakes. However, these pigments and / or dyes are not suitable for use in fibers for tires.

Suitable flame retardants are, for example, antimony trioxide, hexabromocyclododecane, tetrabromobisphenol, bristles, red phosphorus, magnesium hydroxide, aluminum hydroxide, melamine cyanurate and its condensation products such as melam, melem, melon, melamine compounds such as melamine pyrophosphate and polyphosphate, ammonium polyphosphate and organophosphorus compounds or salts thereof such as resorcinol diphenyl phosphate, Phosphonic acid esters or metal phosphinates.

Suitable processing aids are, for example, paraffins, fatty alcohols, fatty acid amides, paraffin waxes, montanates or polysiloxanes.

Suitable stabilizers are, for example, copper salts, molybdenum salts, copper complexes, phosphites, sterically hindered phenols, secondary amines, UV absorbers and HALS stabilizers. In particular, copper salts are good thermal stabilizers to process the material into fibers in the melt spinning process.

The PPA fiber material according to the invention is outstandingly suitable for the production of monofilaments (continuous single fibers) as well as multifilaments (eg yarns each with over 100 endless individual fibers). The fibers can be short or endless. Strength carriers which are best suited are endless multifilaments. The melting temperature varies between about 280 ° C and about 340 ° C, depending on the process and feed viscosity of the molding material. Typical stretching temperatures are in the range of about 160 ° C to about 180 ° C.

The invention will now be explained by way of examples.

For the preparation of the higher melting types of the copolyamide according to the invention, for example, in the 2 of the US 2 361 717 illustrated apparatus. When adjusting to the laboratory scale, the local positions 23 . 24 and 25 be replaced by a high-pressure resistant autoclave, which can ensure a constant discharge pressure through the reactors by an inert gas overlay. In the following examples, the first tubular reactor (corresponding to the position 26 ) has a length of 6 m and an inner diameter of 1.4 mm and the second tubular reactor (corresponds to the position 27 ' ) has a length of 10 m and an inner diameter of 2 mm. Both reactors were operated with an oil flow of 360 ° C.

Example 1: CoPA 10T / TMDT (80:20)

In the autoclave were 675.2 g of 1,10-decanediamine (98.6 percent), 150.3 g of a mixture of 2,2,4- and 2,4,4-TMD, 789.3 g of terephthalic acid, 452 g demineralized water (demineralized water), 3.1 g of a heat stabilizer and 2.88 g of a 5 percent aqueous H ₃ PO ₂ solution filled, rendered inert with nitrogen three times, the autoclave shut off and heated with an oil flow temperature of 230 ° C. This formed a clear, homogeneous saline solution. The autoclave was adjusted to a constant pressure of 44 bar with nitrogen; this pressure conveyed the material through the plant. The flasher (position 30) produced 16.5 g / h of polymer. The analysis results were: carboxyl end group: 113 mmol / kg amino end: 106 mmol / kg

Relative solution viscosity η _rel , measured according to ISO 307 in a 0.5 wt .-% solution in m-cresol at 23 ° C: 1.59 T _g (according to ISO 11357 ): 126 ° C T _m1 (according to ISO 11357 ): 256 ° C (measured at the 2nd heating) T _m2 (according to ISO 11357 ): 278 ° C (main peak, measured at 2nd heating)

The product was post-condensed for 30 h at 180 ° C in a gentle stream of nitrogen in solid phase to a material with η _rel = 1.79.

Example 2: CoPA 10T / TMDT (94: 6)

In the autoclave were added 654.9 g of 1,10-decanediamine (98.6 percent), 38.0 g of a mixture of 2,2,4- and 2,4,4-TMD, 664.6 g terephthalic acid, 372, 5 g of DI water, 1.2 g. Sodium hypophosphite, 2.4 g of a heat stabilizer and 1.2 g of a 5 percent H ₃ PO ₂ solution filled, inertized three times with nitrogen, the autoclave shut off and heated with an oil flow temperature of 230 ° C. This formed a clear, homogeneous salt solution. The autoclave was adjusted to a constant 42 bar total pressure with nitrogen; this pressure conveyed the material through the plant. The flasher produced 17.9 g / h of polymer. The analysis results were: carboxyl end group: 172 mmol / kg amino end: 167 mmol / kg η _rel 1.42 _Tg : 122 ° C T _m: 297 ° C (main peak)

The product was post-condensed for 40 h at 180 ° C in a gentle stream of nitrogen in solid phase to a material with η _rel = 1.74.

Example 3:

As in Example 1, the further copolyamide listed in the following tables was prepared with a decanediamine / TMD ratio of 85:15.

Reference Example 1:

According to Example 1, the homopolymer PA10T was prepared.

Example 4:

To prepare a CoPA 10T / TMDT (70:30), a 30 l stirred autoclave was charged with the following starting materials: 3,962 kg 1,10-decanediamine (as a 99.3% aqueous solution), 1,549 kg 2,2,4- and 2,4,4-trimethylhexamethylenediamine isomer mixture 5.563 kg Terephthalic acid as well 1.12 g a 50% aqueous solution of hypophosphorous acid (equivalent to 0.006 wt .-%) with 5.96 kg VE water

The starting materials were melted in a nitrogen atmosphere and heated with stirring in a closed autoclave to about 220 ° C, with an internal pressure of about 20 bar. This internal pressure was maintained for 2 hours; Thereafter, the melt was further heated to 305 ° C with continuous expansion to atmospheric pressure and then held for 1.5 hours in a stream of nitrogen at this temperature. Subsequently, it was depressurized to atmospheric pressure within 3 hours and nitrogen was passed through the melt for a further 3 hours until no further increase in the melt viscosity was indicated on the basis of the torque. Thereafter, the melt was discharged by means of a gear pump and granulated as a strand. The granules were dried under nitrogen at 110 ° C for 24 hours.
Discharge: 7,4 kg

The product had the following characteristics: Crystalline melting point T _m : 270 ° C Relative solution viscosity η _rel : 1.76 COOH end groups: 291 mmol / kg NH _{2 end} groups: 17 mmol / kg

Example 5:

To prepare a CoPA 12T / TMDT (60:40), a 30 l stirring autoclave was charged with the following starting materials: 3,788 kg 1,12-dodecanediamine (as a 99.4% aqueous solution), 1,982 kg 2,2,4- and 2,4,4-trimethylhexamethylenediamine isomer mixture 5,305 kg Terephthalic acid as well 1.13 g a 50% aqueous solution of hypophosphorous acid (equivalent to 0.006 wt .-%) with 5.96 kg VE water

The starting materials were melted in a nitrogen atmosphere and heated with stirring in a closed autoclave to about 220 ° C, with an internal pressure of about 20 bar. This internal pressure was maintained for 2 hours; Thereafter, the melt was further heated to 295 ° C with continuous expansion to atmospheric pressure and then held for 1.5 hours in a stream of nitrogen at this temperature. Subsequently, it was depressurized to atmospheric pressure within 3 hours and nitrogen was passed through the melt for a further 3 hours until no further increase in the melt viscosity was indicated on the basis of the torque. Thereafter, the melt was discharged by means of a gear pump and granulated as a strand. The granules were dried under nitrogen at 110 ° C for 24 hours.
Discharge: 8,9 kg

The product had the following characteristics: Crystalline melting point T _m : 232 ° C Relative solution viscosity η _rel : 1.53 COOH end groups: 275 mmol / kg NH _{2 end} groups: 84 mmol / kg

Example 6:

To prepare a CoPA 12T / TMDT (70:30), a 30 l stirred autoclave was charged with the following starting materials: 4.356 kg 1,12-dodecanediamine (as a 99.4% aqueous solution), 1,465 kg 2,2,4- and 2,4,4-trimethylhexamethylenediamine isomer mixture 5,258 kg Terephthalic acid as well 1.13 g a 50% aqueous solution of hypophosphorous acid (equivalent to 0.006 wt .-%) with 5,97 kg VE water

The starting materials were melted in a nitrogen atmosphere and heated with stirring in a closed autoclave to about 220 ° C, with an internal pressure of about 20 bar. This internal pressure was maintained for 2 hours; Thereafter, the melt was further heated to 295 ° C with continuous expansion to atmospheric pressure and then held for 1.5 hours in a stream of nitrogen at this temperature. Subsequently, it was depressurized to atmospheric pressure within 3 hours and nitrogen was passed through the melt for a further 3 hours until no further increase in the melt viscosity was indicated on the basis of the torque. Thereafter, the melt was discharged by means of a gear pump and granulated as a strand. The granules were dried under nitrogen at 110 ° C for 24 hours.
Discharge: 9.1 kg

The product had the following characteristics: Crystalline melting point T _m : 257 ° C Relative solution viscosity η _rel : 1.56 COOH end groups: 269 mmol / kg NH _{2 end} groups: 17 mmol / kg

Example 7:

According to Example 6, a copolyamide was prepared with a dodecanediamine / TMD ratio of 75:25.

Examples 8 and 9:

According to Example 4, two copolyamides were prepared with a decandiamine / TMD ratio of 60:40 and 52:48, respectively.

Comparative Examples 1 and 2:

According to Example 4, two copolyamides were prepared with a decanediamine / TMD ratio of 33:67 and 12:88, respectively.

The properties of the polyamides or copolyamides produced are shown in the following tables.

In the 1 the relative water absorption of the product from Example 3 (full contact storage at 23 ° C) is compared with that of a commercial PPA prepared from 1,6-hexamethylenediamine and a dicarboxylic acid mixture of 65 mol% terephthalic acid, 25 mol% isophthalic acid and 10 mol% adipic acid. It can be seen that the water absorption in the copolyamide according to the invention is considerably lower.

Table 3 shows that the product of Example 3 after moisture conditioning (here: full contact storage at 120 ° C in an autoclave) essentially retains its mechanical properties. The increase of the modulus of elasticity in the first case is due to recrystallization. Table 3: Mechanical properties in the dry and in the moisture-conditioned state Product from example 3 Storage [h] Modulus of elasticity according to ISO 527 [MPa] Breaking tension according to ISO 527 [MPa] Elongation at break according to ISO 527 [MPa] Pure 0 2594 81 5 100 2819 80 6th with 30 wt .-% glass fibers 0 8702 273 3 24 8404 269 3

Powder Preparation

The product from example 8 was ground as extruded granules of about 5 mm in length and about 3 mm in diameter on a pin mill (Alpine CW 160). By means of a cooling screw, the feed pellets were cooled down to -50 ° C, accelerated in the grinding chamber up to 220 m / s and triturated between the pins of the counter-rotating grinding discs. In this case, at a throughput of 15 kg / h, a millbase, in which the proportion with a particle diameter of less than 100 microns 50 wt .-% was. The millbase was sieved at 63 μm; the fine fraction obtained had a particle size distribution (determined by means of laser diffraction) of d ₁₀ = 14.9 μm, d ₅₀ = 43.7 μm and d ₉₀ = 75.4 μm.

This fine powder is suitable for the production of fibers for reinforcing rubber bodies.

The production of the fibers

The production of the fibers is possible in the melt spinning process. For this purpose, the fine powder is melted at 300 to 400 ° C and the fibers are drawn off at a speed of 100 to 900 m / min. The viscosity at these temperatures is preferably below 1500 Pas, more preferably below 1000 Pas. The viscosity can be adjusted with suitable plasticizers. After drawing the fibers, a maximum temperature of about 200 ° C should not be exceeded to allow a smooth flow without damaging the fiber. During fiber drawing, stretching rates between 1 and 9, preferably between 1 and 4, should be realized. The spun yarn can be improved in stretching and tempering in terms of its specific tensile strength, since the molecules are uniformly aligned and preserved. The ideal rates here are from 1 to 6, preferably around 4. The annealing temperature should be slightly higher than the glass transition temperature.

In this way, multifilament yarns with the following properties could be produced: 100 to 300 individual filaments (continuous fibers) per yarn, thread count 100 to 2000 dtex. The fibers had moduli of elasticity in the range of 1.75 to 2.4 GPa; the tensile strength was 0.2 to 0.85 GPa. The fiber diameter was 20 to 45 microns. The smaller the fiber diameter, the higher the tensile strength and modulus of elasticity of the fiber.

The fibers / yarns - possibly further processed into textile fabrics - vulcanized into the rubber matrix for reinforcement. The textile processing of the fibers / yarns and the embedding of the reinforcing fibers in the rubber matrix is carried out in a conventional manner according to the usual production processes of the tire industry.

The rubber matrix itself consists of known synthetic and / or natural rubber and may contain the customary in rubber technology fillers such as carbon black or silica.

With the fibers according to the invention, it is possible to at least partially substitute the fiber reinforcement of a tire consisting of Rylon, PET and steel. Thus, instead of a hybrid fiber reinforcement only a single fiber material in the tire is required, which has a lower rubber content and thus a reduced weight compared to the conventional hybrid tire with better strength. In addition, the saving of rubber in the tread and in the sidewall leads to a reduction of the rolling resistance.

The production of a tire

The production of the tire can be carried out using the fibers of the invention as in US Pat. No. 6,016,857 described described.

The improved stiffness, lower weight, and lack of sharp edges on the steel allow for better roll performance, reducing the profile from 8mm to 4mm. This measure reduces the rolling resistance by 5 to 20% depending on the type of tire.

A complete substitution of the hybrid cord length of an R16 car tire with PPA according to the invention leads to a weight reduction of about 25 to 40%, depending on the type of tire. This has a particularly advantageous effect on the moment of inertia of the wheel. Together with the reduced by the lower rubber content rolling resistance can be achieved in an average passenger car thanks to the invention CO ₂ emissions in the order of 0.35 to 1 kg / 100 km. Thus, the CO ₂ savings potential at a specific fiber strength of 1.46 N / tex is 0.65 kg / 100 km.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2007/092226 A2 [0008]
• WO 1996/20842 A1 [0009]
• WO 1995/08011 A1 [0010]
• EP 1170334 A2 [0028]
• US Pat. No. 2,361,717 [0040]
• US 6016857 [0070]

Cited non-patent literature

• Gächter / Müller, Kunststoffadditive, C. Hanser Verlag, 2nd Edition, p. 296 [0031]
• ISO 307 [0042]
• ISO 11357 [0042]
• ISO 11357 [0042]
• ISO 11357 [0042]
• ISO [0062]
• ISO 527 [0062]

Claims (5)

Fiber-reinforced rubber body, in particular vehicle tire, conveyor belt or gear belt, comprising a matrix of vulcanized rubber and fibers embedded in the matrix, characterized in that the fiber material contains at least 30% by weight of a copolyamide derived from the following monomers: a) 50 to 95 mole% of the combination of a diamine selected from the group consisting of 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine and 1,12-dodecanediamine, as well as terephthalic acid, and b) from 5 to 50 Mol% of the combination of a diamine selected from the group consisting of 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine and mixtures thereof, and terephthalic acid, the stated molar% being based on the sum of the components a) and b) relate. Rubber body according to claim 1, characterized in that the copolyamide additionally contains a maximum of 30 mol% of building blocks, which are derived from other monomers. Rubber body according to claim 1 or 2, characterized in that the fiber material is pure copolyamide. Rubber body according to claim 1 or 2, characterized in that the fiber material in addition to the copolyamide contains at least 0.1 wt .-% of additives. Rubber body according to one of claims 1 to 4, characterized gekekennzeichnet that the matrix in addition to vulcanized synthetic and / or natural rubber fillers such as carbon black and / or silica in particular.

Images