DE102007057719A1 - Thermoplastic molding material useful for making monofilaments comprises a polyamide, a crosslinking agent and an impact modifier - Google Patents

Abstract

Thermoplastic molding material comprises 50-99 wt.% of a polyamide, 0.01-10 wt.% of a crosslinking agent and 0.1-30 wt.% of an impact modifier. Independent claims are also included for: (1) producing monofilaments by converting the molding material into granules, drying the granules at 80[deg] C for at least 6 weeks until the moisture content is 0.04% or less, melting the granules in a single-screw extruder and spinning the melt; (2) monofilaments produced as above.

Description

The The present invention relates to thermoplastic molding compositions based on polyamides with viscosity enhancing additives, extrudates made therefrom and monofilaments and their uses as cords, ropes or ropes, preferably trimmer cords or mowing threads.

To the Pruning of hedges, bushes, lawn edges and other vegetation in forestry, parks or gardens are preferred cutting devices used the plants by means of a propeller-like rotating in a circle Cut nylon thread. In doing so, the material of the thread high demands on toughness and flexibility At the same time, however, they are also Appearance and the feel of a uniform Strength and a smooth surface of the strand required. Established materials for making trimmer strings are polyamides or copolyamides, the other additives impact modifiers can contain.

Problematic for mowing threads made of polyamide is the pronounced Tilt of the cord, due to the high mechanical stress at the end to splice and fringe. Despite the high tenacity Of the materials used, this behavior is the crucial one limiting factor regarding the possible duration of use of the thread. The mechanical damage of individual fibers within polyamide-based ropes and ropes is also a problem when mooring ships.

Known is that the mechanical strength of polyamide by addition can be increased by molecular weight increasing additives. Increasing the toughness of polyamide compounds by adding viscosity-increasing reagents can already take place during the polymerization, as in the following fonts will be executed.

DE 4 100 909 A1 states that addition of 0.2 part of 2,6-dicarboxy-4H-pyran-4-one diethyl ester during the polymerization of caprolactam leads to increased melt viscosity.

In DE 19 859 929 A1 describes a reaction of caprolactam with multifunctional amines and a dicarboxylic acid with subsequent solid phase postcondensation to a product with increased melt viscosity.

Farther Processes are used in which viscosity increasing Means in the melt of a product already present as a polymer be applied, as the following examples show.

JP 60248730 A teaches the addition of 1% 2,2'-m-phenylenebis (2-oxazoline) adipic acid to a polyamide melt and subsequent spinning of the melt to a product of increased molecular weight.

DE 10 042 176 A1 describes polyamide compositions for extrusion blow molding processing containing bisphenol A based epoxy resins as a viscosity modifier and glass fibers.

In WO 2001 053382 A1 Polyamide compositions are claimed which contain bis-N-acylbislactams such as adipoylbiscaprolactam, isophthaloylbiscaprolactam or terephthaloylbiscaprolactam and have increased relative viscosities. The polymers obtained are suitable for the production of nylon fibers and do not appear to show any special properties of the monofilaments. Rather, the focus is on the faster molecular weight build-up in comparison to solid-state postcondensation. As a result of the possible bypassing of a tempering less oxidative side reactions and branching should occur.

JP 60088035 teaches a method for increasing the viscosity of an aromatic copolyamide obtainable from 80% AH salt, 10% p-phenylenediamine and 10% terephthalic acid by dosing 1% N, N-diglycidylhydantoin into the polymer melt at 280 ° C and then spinning to fibers under drawing in front. These fibers have a relative solution viscosity of 2.90, a Young's modulus of 84 g / denier, a tenacity of 9.5 g / denier, and retain their strength at 91% after annealing at 200 ° C for one hour. For a corresponding conventional PA66 monofilament, by comparison, a relative solution viscosity of 2.85, a Young's modulus of 45 g / denier, a strength of 9.0 g / denier and a retention of the above-mentioned temper of 88% are mentioned.

WO 96 34909 A1 teaches the reaction of polyamide 6 in the melt with the addition of N, N'-Tereph thaloyl-bis-laurolactam and 2,2'-m-phenylenebis (2-oxazoline) to give products which are particularly suitable for extrusion and blow molding applications. The claimed compositions should contain less caprolactam compared to correspondingly viscous polyamides obtained by solid state post-condensation. As a result, the materials mentioned are primarily suitable for food contact applications. However, the application does not address the possible suitability of monofilament extrusion products.

As WO 98 47940 A1 describes the addition of 0.666 parts of carbonyl-bislactam to a polyamide 6 melt with kneading at 240 ° C after only 2 minutes to a significantly increased relative viscosity, while the corresponding viscosity with subsequent condensation of the polyamide without the above addition, the corresponding viscosity only is reached after more than 10 minutes. The use of the resulting polyamides for spinning into fibers is cited without indicating test values of the fibers compared to conventional reference materials.

WO 2007 009540 discloses a process for increasing the viscosity of polybutylene terephthalate in solution using bis-lactams, cyclic amino ethers, siloxanes and thiols as reagents. The resulting solutions are then spun into fibers in a suitable bath. The obtained PBT monofilament is characterized by a tensile strength of 20 cN / dtex and a tensile modulus of 25 N / tex, with no references to materials of the prior art.

A build-up of the viscosity of polyamide melt by means of carbonyl bislactam and a diepoxide is disclosed in EP-A 1 553 122 presented. The reaction takes place during the extrusion process. This process is characterized by a good preservation of the product color. In the EP-A 1 553 122 claimed materials stand out from those according to WO 9847940 A1 by a higher breaking strength of the fiber, this statement is not substantiated by test values.

In EP 1 338 616 A1 Blocked diisocyanates are described which lead to an increase in viscosity when incorporated in polyamide melts. The suitability of the mixtures according to the invention for spinning into fibers is mentioned without carrying out more concrete examples thereof.

The to increase the viscosity of substances used improve the mechanical properties of monofilaments, they However, at the same time the drawability of the extruded Stranges to a uniform monofilament through Formation of crosslinked gel bodies and associated Affect thick spots.

task The present invention was therefore to provide polyamide compositions for Production of splice-resistant cords or ropes, compared to pure polyamide increased by a mechanical strength (splice resistance) and yet to thicken-free monofilaments in the extrusion can be stretched.

Surprisingly was found to be one with a viscosity-enhancing one Reagent compounded polyamide in the extrusion to a non-staining Monofilament is stretchable.

• A) 50 bis 99 Gew.-% eines Polyamides,
• B) 0,01 bis 10 Gew.-%, bevorzugt 0,1 bis 1 Gew.-%, besonders bevorzugt 0,3 bis 0,8 Gew.-% eines multifunktionalen, die Viskosität von Polyamid erhöhenden Reagenzes und
• C) 0,1 bis 30 Gew.-%, bevorzugt 1,0 bis 20 Gew.-%, besonders bevorzugt 3,0 bis 8,0 Gew.-% eines Elastomermodifikators.

The invention therefore thermoplastic molding compositions containing at least

• A) 50 to 99% by weight of a polyamide,
• B) 0.01 to 10 wt .-%, preferably 0.1 to 1 wt .-%, particularly preferably 0.3 to 0.8 wt .-% of a multifunctional, the viscosity of polyamide-increasing reagent and
• C) 0.1 to 30 wt .-%, preferably 1.0 to 20 wt .-%, particularly preferably 3.0 to 8.0 wt .-% of an elastomer modifier.

The Polyamide compositions according to the invention are suitable especially for the extrusion of monofilaments for the production of ropes and cords as well as turn off the trimmer cords or Mowing in trimmers. As beneficial for the flexibility and durability of the trimmer line of the mowing thread is the addition of an elastomeric modifier been found.

• A) 50 bis 99 Gew.-% eines Polyamides, bevorzugt Polyamid 6, besonders bevorzugt Polyamid 6 mit einer relativen Lösungsviskosität in m-Kresol von 2,0 bis 5,0,
• B) 0,01 bis 10 Gew.-%, bevorzugt 0,1 bis 1 Gew.-%, besonders bevorzugt 0,3 bis 0,8 Gew.-% eines multifunktionalen, die Viskosität von Polyamid erhöhenden Reagenzes, bevorzugt derivatisiert mit Caprolactamgruppen oder Epoxidgruppen und
• C) 0,1 bis 30 Gew.-%, bevorzugt 1,0 bis 20 Gew.-%, besonders bevorzugt 3,0 bis 8,0 Gew.-% eines Elastomermodifikators, bevorzugt basierend auf Olefincopolymeren.

The invention therefore preferably relates to thermoplastic molding compositions containing at least

• A) from 50 to 99% by weight of a polyamide, preferably polyamide 6, more preferably polyamide 6 having a relative solution viscosity in m-cresol of from 2.0 to 5.0,
• B) 0.01 to 10 wt .-%, preferably 0.1 to 1 wt .-%, particularly preferably 0.3 to 0.8 wt .-% of a multi functional, the viscosity of polyamide-increasing reagent, preferably derivatized with caprolactam groups or epoxide groups and
• C) 0.1 to 30 wt .-%, preferably 1.0 to 20 wt .-%, particularly preferably 3.0 to 8.0 wt .-% of an elastomer modifier, preferably based on olefin copolymers.

When Component A) contain the thermoplastic molding compositions according to the invention at least a thermoplastic polyamide, preferably polyamide 6. Particularly Both polyamide 6 with relative solution viscosities are preferred in m-cresol from 2.0 to 5.0, particularly preferably polyamide 6 with a relative solution viscosity in m-cresol from 2.7-4.0, particularly preferably from 3.5. The polyamides according to the invention can according to different procedures as well as from different building blocks be synthesized and in the specific application alone or in combination with processing aids, stabilizers, polymeric Alloy partners (eg other types of polyamide) or reinforcing materials (such as z. As mineral fillers), to materials with special set property combinations are equipped. Also suitable are blends with shares of other polymers z. As of polyethylene, polypropylene, ABS, where appropriate, a or more compatibilizers can be used.

to Preparation of polyamides are a variety of procedures known, depending on the desired end product different Monomer components, various chain regulators for setting a desired Molecular or even monomers with reactive groups for later intended post-treatments are used.

The technically relevant process for the production of polyamides run mostly via the polycondensation in the melt. In this Also included is the hydrolytic polymerization of lactams as polycondensation Understood.

According to the invention preferred Polyamides are partially crystalline polyamides starting from diamines and Dicarboxylic acids and / or lactams with at least 5 ring members or corresponding amino acids can be produced. As starting materials are preferably aliphatic and / or aromatic dicarboxylic acids, particularly preferably adipic acid, 2,2,4-trimethyladipic acid, 2,4,4-trimethyladipic acid, azelaic acid, sebacic acid, Isophthalic acid, terephthalic acid, aliphatic and / or aromatic diamines, more preferably tetramethylenediamine, Hexamethylenediamine, 1,9-nonanediamine, 2,2,4- and 2,4,4-trimethylhexamethylenediamine, the isomers diamino-dicyclohexylmethane, diaminodicyclohexylpropane, Bis-aminomethyl-cyclohexane, phenylenediamines, xylylenediamines, aminocarboxylic acids, in particular aminocaproic acid, or the corresponding Lactams are considered. Copolyamides of several of the monomers mentioned are included.

Especially Preference is given to caprolactams, ε-caprolactam is very particularly preferred used.

Especially most preferred according to the invention are still preferred on PA6, PA66 and others on aliphatic and / or aromatic Polyamides or copolyamides based compounds in which a Polyamide group in the polymer chain come from 3 to 11 methylene groups.

to Determination of the solution viscosity becomes a solution of 1% of the polyamide sample prepared in m-cresol. To the full Dissolving the entire polymer, the approach is 6 hours at 75 ° C in a suitably tempered shaker emotional. After the solution has cooled to 25 ° C is filtered through a G1 glass frit.

The Measurement is carried out with a Lauda PV 24 Ubbelohde viscometer. to Measurement becomes a capillary of type No. 54523 from Schott Instruments GmbH (Mainz) with a capillary inner diameter of 1.36 mm. The viscosity of the pure solvent and the subsequently determined viscosity sample solution finally provide the relative solution viscosity the polymer sample.

Component B) contains the thermoplastic molding compositions of the invention as a chemically reactive additive. It is multifunctional, the viscosity of polyamide-increasing reagents that link two or more polyamide chain molecules via formation of covalent bonds and thus increase the average molecular weight of the polyamide. The reagents may themselves already be an oligomer or else a polymer. The multifunctional additives react in the polyamide melt, preferably during extrusion. In the linking reaction, both linear and branched polyamides can be formed. As component B) are preferably with epoxide groups or capro lactam groups derivatized compounds used. Particular preference is given to using difunctional epoxy resins based on bisphenol A, blocked aliphatic polyisocyanates based on isophorone diisocyanate, blocked cycloaliphatic polyisocyanates or carbonylbiscaprolactam.

• A) 50 bis 99 Gew.-% eines Polyamides, bevorzugt Polyamid 6, besonders bevorzugt Polyamid 6 mit einer relativen Lösungsviskosität in m-Kresol von 2,0 bis 5,0,
• B) 0,01 bis 10 Gew.-%, bevorzugt 0,1 bis 1 Gew.-%, besonders bevorzugt 0,3 bis 0,8 Gew.-% difunktionelle Epoxidharze auf Basis von Bisphenol-A, blockierte aliphatische Polyisocyanate auf Basis von Isophorondiisocyanat, blockierte cycloaliphatische Polyisocyanate oder Carbonylbiscaprolactam und
• C) 0,1 bis 30 Gew.-%, bevorzugt 1,0 bis 20 Gew.-%, besonders bevorzugt 3,0 bis 8,0 Gew.-% eines Elastomermodifikators, bevorzugt basierend auf Olefincopolymeren.

The invention therefore particularly preferably relates to thermoplastic molding compositions containing at least

• A) from 50 to 99% by weight of a polyamide, preferably polyamide 6, more preferably polyamide 6 having a relative solution viscosity in m-cresol of from 2.0 to 5.0,
• B) 0.01 to 10 wt .-%, preferably 0.1 to 1 wt .-%, particularly preferably 0.3 to 0.8 wt .-% of difunctional epoxy resins based on bisphenol-A, blocked aliphatic polyisocyanates based of isophorone diisocyanate, blocked cycloaliphatic polyisocyanates or carbonylbiscaprolactam and
• C) 0.1 to 30 wt .-%, preferably 1.0 to 20 wt .-%, particularly preferably 3.0 to 8.0 wt .-% of an elastomer modifier, preferably based on olefin copolymers.

• A) 50 bis 99 Gew.-% eines Polyamides, bevorzugt Polyamid 6, besonders bevorzugt Polyamid 6 mit einer relativen Lösungsviskosität in m-Kresol von 2,0 bis 5,0,
• B) 0,01 bis 10 Gew.-%, bevorzugt 0,1 bis 1 Gew.-%, besonders bevorzugt 0,3 bis 0,8 Gew.-% blockierte aliphatische Polyisocyanate auf Basis von Isophorondiisocyanat oder blockierte cycloaliphatische Polyisocyanate und
• C) 0,1 bis 30 Gew.-%, bevorzugt 1,0 bis 20 Gew.-%, besonders bevorzugt 3,0 bis 8,0 Gew.-% eines Elastomermodifikators, bevorzugt basierend auf Olefincopolymeren.

The invention therefore particularly particularly preferably relates to thermoplastic molding compositions containing at least

• A) from 50 to 99% by weight of a polyamide, preferably polyamide 6, more preferably polyamide 6 having a relative solution viscosity in m-cresol of from 2.0 to 5.0,
• B) 0.01 to 10 wt .-%, preferably 0.1 to 1 wt .-%, particularly preferably 0.3 to 0.8 wt .-% of blocked aliphatic polyisocyanates based on isophorone diisocyanate or blocked cycloaliphatic polyisocyanates and
• C) 0.1 to 30 wt .-%, preferably 1.0 to 20 wt .-%, particularly preferably 3.0 to 8.0 wt .-% of an elastomer modifier, preferably based on olefin copolymers.

Of the Elastomeric modifier as component C) is the inventive thermoplastic molding compounds to increase the impact strength added. These elastomer modifiers are preferred to copolymers composed of at least two monomers of the series Ethylene, propylene, butadiene, isobutene, isoprene, chloroprene, vinyl acetate, Styrene, acrylonitrile or acrylic or methacrylic acid esters with 1 to 18 C atoms in the alcohol component. The copolymers can optionally compatibilizing groups such as maleic anhydride or epoxy. As component C) is particularly preferred a maleic anhydride functionalized, elastomeric Ethylene copolymer used.

• D) 0,01 bis 10,0 Gew.-%, bevorzugt 0,1 bis 5,0 Gew.-% weitere Additive enthalten. Weitere Additive der Komponente D) sind bevorzugt Stabilisatoren, besonders bevorzugt UV-Stabilisatoren, Thermostabilisatoren, Gammastrahlenstabilisatoren, Hydrolysestabilisatoren, sowie Antistatika, Emulgatoren, Nukleierungsmittel, Weichmacher, Verarbeitungshilfsmittel, Farbstoffe oder Pigmente. Die genannten und weitere geeignete Additive sind zum Beispiel beschrieben im Plastics Additives Handbook, 5th Edition, Hanser-Verlag, München, 2001, Seiten 80–84, 546–547, 688, 872–874, 938, 966 . Die Additive können alleine oder in Mischung bzw. in Form von Masterbatchen eingesetzt werden.

In a preferred embodiment, the thermoplastic molding compositions according to the invention in addition to the components A), B) and C) still

• D) 0.01 to 10.0 wt .-%, preferably 0.1 to 5.0 wt .-% further additives. Further additives of component D) are preferably stabilizers, particularly preferably UV stabilizers, heat stabilizers, gamma ray stabilizers, hydrolysis stabilizers, and also antistatic agents, emulsifiers, nucleating agents, plasticizers, processing aids, dyes or pigments. The above-mentioned and other suitable additives are described, for example, in US Pat Plastics Additives Handbook, 5th Edition, Hanser-Verlag, Munich, 2001, pages 80-84, 546-547, 688, 872-874, 938, 966 , The additives can be used alone or mixed or in the form of masterbatches.

According to the invention preferred Stabilizers are sterically hindered phenols and / or phosphites, hydroquinones, aromatic secondary amines such as diphenylamines, substituted Resorcine, salicylates, benzotriazoles and benzophenones, as well as various substituted representatives of these groups and / or mixtures thereof.

When UV stabilizers are preferably various substituted resorcinols, Salicylates, benzotriazoles or benzophenones used.

Prefers Dyes or pigments to be used may be inorganic Pigments, particularly preferably titanium dioxide, ultramarine blue, iron oxide, Zinc sulfide or carbon black, as well as organic pigments, more preferred Phthalocyanines, quinacridones, perylenes, and dyes such as nigrosine and anthraquinones as colorants as well as other colorants.

When Nucleating agents are preferably sodium or calcium phenylphosphinate, Alumina, silica or talc, especially preferred Talc used.

• E) 0,01 bis 5,0 Gew.-%, bevorzugt 0,05 bis 1,0 Gew.-% Gleit- und/oder Entformungsmittel enthalten. Bevorzugte Gleit und/oder Entformungsmittel sind langkettige Fettsäuren (z. B. Stearinsäure), deren Salze (z. B. Ca- oder Zn-Stearat) sowie deren Esterderivate oder Amidderivate (z. B. Ethylen-bis-stearylamid), Montanwachse (z. B. Ester von Montansäuren mit Ethylenglycol) sowie niedermolekulare Polyethylen- bzw. Polypropylenwachse. Erfindungsgemäß besonders bevorzugte Gleit- und/oder Entformungsmittel sind aus der Gruppe der Ester oder Amide gesättigter oder ungesättigter aliphatischer Carbonsäuren mit 8 bis 40 C-Atomen mit aliphatischen gesättigten Alkoholen oder Aminen mit 2 bis 40 C-Atomen enthalten.

In a further preferred embodiment, the novel thermoplastic molding compositions may be used in addition to the components A), B), C) and optionally D) or instead of the component D) yet

• E) 0.01 to 5.0 wt .-%, preferably 0.05 to 1.0 wt .-% lubricants and / or mold release agents. Preferred lubricants and / or mold release agents are long-chain fatty acids (eg stearic acid), their salts (eg Ca or Zn stearate) and also their ester derivatives or amide derivatives (eg ethylene-bis-stearylamide), montan waxes ( eg esters of montan acids with ethylene glycol) as well as low molecular weight polyethylene or polypropylene waxes. Inventively particularly preferred lubricants and / or mold release agents are from the group of esters or amides of saturated or unsaturated aliphatic carboxylic acids having 8 to 40 carbon atoms with aliphatic saturated alcohols or amines having 2 to 40 carbon atoms.

• A) Polyamid 6 oder Polyamid 66
• B) difunktionelle Epoxidharze auf Basis von Bisphenol-A, blockierte aliphatische Polyisocyanate auf Basis von Isophorondiisocyanat, blockierte cycloaliphatische Polyisocyanate oder Carbonylbiscaprolactam und
• C) Maleinsäureanhydrid-funktionalisiertes, elastomeres Ethylencopolymer

A particularly preferred embodiment of the present invention relates to thermoplastic molding compositions containing at least

• A) polyamide 6 or polyamide 66
• B) difunctional epoxy resins based on bisphenol A, blocked aliphatic polyisocyanates based on isophorone diisocyanate, blocked cycloaliphatic polyisocyanates or carbonylbiscaprolactam and
• C) Maleic anhydride functionalized elastomeric ethylene copolymer

• A) Polyamid 6B
• B) difunktionelle Epoxidharze auf Basis von Bisphenol-A,
• C) Maleinsäureanhydrid-funktionalisiertes, elastomeres Ethylencopolymer

Particular preference is given to containing thermoplastic molding compositions

• A) Polyamide 6B
• B) difunctional epoxy resins based on bisphenol A,
• C) Maleic anhydride functionalized elastomeric ethylene copolymer

• A) 50 bis 99 Gew.-%, eines Polyamides, bevorzugt Polyamid 6
• B) 0,01 bis 10 Gew.-%, bevorzugt 0,1 bis 1 Gew.-%, besonders bevorzugt 0,3 bis 0,8 Gew.-% eines multifunktionalen, die Viskosität von Polyamid erhöhenden Reagenzes und
• C) 0,1 bis 30 Gew.-%, bevorzugt 1,0 bis 20 Gew.-%, besonders bevorzugt 3,0 bis 8,0 Gew.-% eines Elastomermodifikators zur Herstellung von Monofilamenten.

The present invention further relates to the use of the thermoplastic molding compositions containing at least

• A) 50 to 99 wt .-%, of a polyamide, preferably polyamide 6
• B) 0.01 to 10 wt .-%, preferably 0.1 to 1 wt .-%, particularly preferably 0.3 to 0.8 wt .-% of a multifunctional, the viscosity of polyamide-increasing reagent and
• C) 0.1 to 30 wt .-%, preferably 1.0 to 20 wt .-%, particularly preferably 3.0 to 8.0 wt .-% of an elastomer modifier for the production of monofilaments.

The however, the present invention also relates to the monofilaments available by converting the thermoplastic described above Molding compounds in granules, drying this or a previously prepared granule mixture at least 6 weeks at 80 ° C up to a maximum humidity 0.04%, then melting the granules in one Single-screw extruder and spinning off the melt.

The The present invention also relates to processing the monofilaments to thaw or lace, preferably to Timmerschnüren or mowing threads, what to the methods known to those skilled in the art.

The The invention further relates to the use of these ropes or cords for tying pressed bales, for example, from raw materials, preferably cotton, clothing, paper, waste paper, for fixing or transporting large items up to Ships as well as the assembly of strings into trimmer strings or mowing threads for use in equipment for trimming flowers, perennials, bushes, hedges, trees, Lawn or other cultivated or naturally occurring Plants, trimmer cord or mowing wires, to guy wire for fences in vineyards and fruit growing, to ground fabric for filtration, paper machine clothing, conveyor belts or as a reinforcement for rubber.

• A) 50 bis 99 Gew.-% eines Polyamides,
• B) 0,01 bis 10 Gew.-%, bevorzugt 0,1 bis 1 Gew.-%, besonders bevorzugt 0,3 bis 0,8 Gew.-% eines multifunktionalen, die Viskosität von Polyamid erhöhenden Reagenzes und
• C) 0,1 bis 30 Gew.-%, bevorzugt 1,0 bis 20 Gew.-%, besonders bevorzugt 3,0 bis 8,0 Gew.-% eines Elastomermodifikators dadurch gekennzeichnet, dass man die Komponenten in den entsprechenden Gewichtsanteilen mischt indem man sie gemeinsam compoundiert oder indem man entsprechende Zusammensetzungen durch Mischen von separat für sich compoundierten Vorprodukten in Form von Granulatgemischen (Dryblends) der weiteren Verarbeitung durch Extrusion zuführt.

The preparation of the thermoplastic molding compositions according to the invention is carried out by known methods by mixing the components in the polymer melt. The mixing of the components takes place in the corresponding proportions by weight. Preferably, the mixing (compounding) of the components at temperatures of 220 to 360 ° C by mixing together, mixing, kneading, extruding or rolling of the components, more preferably by compounding on a counter-rotating twin-screw extruder or Buss kneader. It may be advantageous to premix individual components. The molding compositions thus prepared can be further processed by extrusion or granulation. It may also be advantageous to moldings or semi-finished products from a physical mixture (dry blend) of premixed components and / or individual components produced at room temperature (preferably 0 to 40 ° C.), for example. B. in the form of granules directly on the extrusion line for the semifinished product or monofilament, z. B. on a single-screw extruder to produce. The present invention therefore also relates to a process for the preparation of thermoplastic molding compositions containing

• A) 50 to 99% by weight of a polyamide,
• B) 0.01 to 10 wt .-%, preferably 0.1 to 1 wt .-%, particularly preferably 0.3 to 0.8 wt .-% of a multi functional, the viscosity of polyamide increasing reagent and
• C) 0.1 to 30 wt .-%, preferably 1.0 to 20 wt .-%, particularly preferably 3.0 to 8.0 wt .-% of an elastomer modifier, characterized in that mixing the components in the corresponding proportions by weight by compounding them together or by adding appropriate compositions by mixing of separately compounded precursors in the form of dry blends for further processing by extrusion.

Possibly can the compositions obtained in this way for ease of handling by re-extruding into one homogeneous granules are processed further.

The The above-mentioned preferred embodiments also apply for the inventive method. Mix in the sense of the present invention also means mixing, kneading, extrude or roll. Mixing also means the physical Matching and mixing granules of different Composition to a resulting total composition, those obtained by mixing in the melt and into granules uniform composition reclaimed composition in Sum can correspond.

The present invention further relates to the production of monofilaments from the granules to be produced according to the invention or the granule mixtures corresponding to the entire composition. For this purpose, the granules or granules mixture is dried for at least 6 weeks at 80 ° C until a maximum moisture of 0.04% is reached. Subsequently, the granules in a single-screw extruder, z. B. reef houses 90 melted with dynamic mixing elements. The spinning off of the melt takes place as in Hensen-Knappe-Potente, Kunststoff-Extrusionstechnik 11, Extrusion Plants, Hanser-Verlag "pages 295-319 , Finally, the monofilaments are wound up on coils and assembled. The monofilaments according to the invention can then be processed into cords as already described above and used in particular as trimmer cords in grass trimmers.

The However, the present invention also relates to the use of multifunctional, the viscosity of polyamide increasing reagents component B), preferably of difunctional epoxy resins Based on bisphenol-A, blocked aliphatic polyisocyanates based on isophorone diisocyanate, blocked cycloaliphatic Polyisocyanates or carbonylbiscaprolactam to increase the splice resistance of strings in particular trimmer cords or mowing threads.

Examples

To the Proof of the improvements recommended according to the invention were initially by compounding corresponding polyamide molding compounds prepared. The individual components were in a twin-screw extruder of the type ZSK 32 Compounder of the company Coperion Werner & Pfleiderer (Stuttgart, Germany) mixed at temperatures between 260 and 290 ° C, as a strand discharged into a water bath until granular cooled and granulated (Table 1). Alternatively, the Ingredients in appropriate proportions in Form of polyamide-based prefabricated granules (masterbatches) and pure polyamide as a granule mixture (dry blend) brought together and in the same way as the homogeneously compounded granules dried and further processed (Table 2).

To drying at 80 ° C up to a maximum humidity 0.04% was the processing of the granules on a reefer houses 90 single-screw extruder with dynamic mixing elements (3DD mixer) too Monofilaments. The following compositions were after processed as described above.

The monofilaments obtained were then tested for their mechanical properties. For this purpose, the strength and the maximum tensile strength became weaker DIN EN 13895 certainly. The impact test was carried out (see 1 ) by a piece of monofilament 1 of 12 cm length at one end so on a rotating rod 2 was attached, that the free end at every turn on a fixed second rod 3 or stone hit. Preferably, a stone was used for whipping. At a speed of 10,000 revolutions per minute, the monofilament end was impacted against the impactor for 30 seconds and then measured the remaining length. The longer the remainder left, the more mechanically stable the monofilament was. In addition, the condition of the free end after the test (wear pattern) was also evaluated. Uniform wear means higher quality of the monofilament.

To determine the Flex-Number or buckling fracture number, a monofilament piece was clamped at both ends in independently movable holding devices, which the monofilament by a connecting rod device (see 2 , Apparatus for the determination of the flex number (Flex Number)) bent alternately in the opposite direction at right angles. The number of buckling operations until the breaking of the monofilament was determined by an automatic counter. The measurement was carried out 6 times and the mean value was formed. Tab. 1: Exemplary embodiments of the thermoplastic molding compositions according to the invention as homogeneous compounds. example 1 Example 2 Example 3 A) polyamide (ŋ _rel = 3.5),% 93.19 99.19 Polyamide ( _ŋrel = 3.1),% 93.19 B) Reactive additive,% 0.51 0.51 0.51 C) impact modifier,% 6.00 6.00 E) wax,% 0.30 0.30 0.30 Monofilament testing: Diameter, mm 1.6 1.6 1.6 Strength, cN / tex 26.2 28.0 23.5 Maximum tensile strength elongation,% 60.1 57.4 64.3 Flex Number 1310 900 1150 Normalized bending stiffness, Nmm ² 105 150 95 Remaining length after impact test, cm 9.2 to 10.7 3.1 to 8.0 9.0 to 10.2 wear pattern evenly unequally evenly Tab. 2: Exemplary embodiments of the thermoplastic molding compositions according to the invention in the form of granule mixtures (dry blends). Example 4 Example 5 Reference Example 1 Reference Example 2 A) polyamide (ŋ _rel = 3.5),% 93.49 94.00 Polyamide ( _ŋrel = 3.1),% 93.49 100 B) Reactive additive,% 0.51 0.51 C) impact modifier,% 6.00 6.00 6.00 Monofilament testing: Diameter, mm 1.6 1.6 1.6 1.6 Strength, cN / tex 26.5 22.3 18.5 24.0 Maximum tensile strength elongation,% 58.2 59.0 72.3 57.8 Flex Number 1280 1200 1000 700 Normalized bending stiffness, Nmm ² 109 92 85 125 Remaining length after impact test, cm 8.9 to 10.4 9.3 to 10.5 5.8 to 9.5 0 to 8.1 wear pattern evenly evenly unequally unequally

• Thermoplast, z. B. Polyamid 6, linear, mit einer relativen Lösungsviskösität einer 1%igen Lösung in m-Kresol von 3,1 oder 3,5
• Reaktives Additiv, z. B. Araldit^® GY 764 von Huntsman, Allinco^® CBC von DSM, Crelan^® UI oder Crelan^® NI-2 von Bayer Material Science
• Schlagzähmodifikator, z. B. Exxelor^® VA 1801 von Exxon Mobil
• Wachs, z. B. Licowax^® E Flakes von Clariant GmbH

Used material:

• Thermoplastic, z. As polyamide 6, linear, with a relative solution viscosity of a 1% solution in m-cresol of 3.1 or 3.5
• Reactive additive, eg. As Araldit ^® GY 764 from Huntsman, Allinco CBC ^® from DSM, Crelan UI ^® or Crelan ^® NI-2 from Bayer MaterialScience
• Impact modifier, z. B. Exxelor ^® VA 1801 Exxon Mobil
• Wax, z. B. Licowax ^® E flakes of Clariant GmbH

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• - DE 4100909 A1 [0005]
• - DE 19859929 A1 [0006]
• - JP 60248730 A [0008]
• - DE 10042176 A1 [0009]
• WO 2001053382 A1 [0010]
• - JP 60088035 [0011]
• WO 9634909 A1 [0012]
• WO 9847940 A1 [0013, 0015]
• - WO 2007009540 [0014]
• EP 1553122A [0015, 0015]
• - EP 1338616 A1 [0016]

Cited non-patent literature

• Plastics Additives Handbook, 5th Edition, Hanser-Verlag, Munich, 2001, pages 80-84, 546-547, 688, 872-874, 938, 966 [0035]
• - "Hensen-Knappe-Potente, Kunststoff-Extrusionstechnik 11, Extrusion Systems, Hanser-Verlag" pages 295-319 describes [0050]
• - DIN EN 13895 [0054]

Claims (16)

Themoplastic molding compositions, characterized in that at least A) 50 to 99 wt .-% of a polyamide, B) 0.01 to 10 wt .-%, preferably 0.1 to 1 wt .-%, particularly preferably 0.3 to 0 , 8 wt .-% of a multifunctional, the viscosity of polyamide-increasing reagent and C) 0.1 to 30 wt .-%, preferably 1.0 to 20 wt .-%, particularly preferably 3.0 to 8.0 wt. -% of an elastomer modifier. Thermoplastic molding compositions according to claim 1, characterized in that used as component A) polyamide 6 becomes. Thermoplastic molding compositions according to claim 1, characterized in that as component B) reagents, the two or more polyamide chain molecules via Link training of covalent bonds and thus increase the average molecular weight of the polyamide, be used. Thermoplastic molding compositions according to claim 3, characterized in that it is at the component B) with epoxy groups or caprolactam-derivatized compounds preferably difunctional epoxy resins based on bisphenol A, blocked aliphatic polyisocyanates based on isophorone diisocyanate, blocked cycloaliphatic polyisocyanates or carbonylbiscaprolactam. Thermoplastic molding compositions according to one of claims 1 to 4, characterized in that as a component C) copolymers composed of at least two monomers of the series Ethylene, propylene, butadiene, isobutene, isoprene, chloroprene, vinyl acetate, Styrene, acrylonitrile or acrylic or methacrylic acid esters with 1 up to 18 carbon atoms are used in the alcohol component. Thermoplastic molding compositions according to one of claims 1 to 5, characterized in that additionally as component D) further additives, preferably UV stabilizers, Heat stabilizers, gamma ray stabilizers, hydrolysis stabilizers, Antistatic agents, emulsifiers, neutralizing agents, plasticizers, processing aids, Dyes and pigments, alone or in mixture or in the form of Masterbatchen be used. Thermoplastic molding compositions according to one of claims 1 to 5, characterized in that as additional Component or instead of component D) the component E) sliding and / or mold release agents are used. Thermoplastic molding compositions according to one of claims 1 to 6, characterized in that as additional Component or instead of components D) and / or E) the component F) fillers are used. Process for the preparation of the thermoplastic molding compositions according to claims 1 to 8, characterized that you have the components in the appropriate proportions by weight mixes or compounded. A method according to claim 9, characterized characterized in that at temperatures of 220 to 360 ° C is working. Use of the thermoplastic molding compositions according to Claims 1 to 8, preferably of granules produced therefrom for the production of monofilaments. Process for producing monofilaments, characterized characterized in that the thermoplastic molding compositions according to the Claims 1 to 8 converted into granules, the granules or a previously prepared granule mixture at least Dried at 80 ° C for 6 weeks until a maximum of moisture 0.04%, the granules are then in a Single-screw extruder, melted and the melt spins off Monofilament available by transfer the thermoplastic molding compositions according to claims 1 to 8 in granules, dry this or a previously prepared Granulate mixture for at least 6 weeks at 80 ° C to a Humidity of a maximum of 0.04%, melting of the granules then in a single-screw extruder and spinning off the melt. Use of the monofilaments according to claim 12 for the production of ropes, ropes or cords. Use of the cords according to claim 13 for the production of trimmer cord or mowing wires, guy wire for fences in vineyards and fruit growing, ground fabric for filtration, paper machine clothing, conveyor belts or as a reinforcement for rubber. Use of multifunctional, the viscosity polyamide-increasing reagents of component B), preferably of difunctional epoxy resins based on bisphenol-A, blocked aliphatic polyisocyanates based on isophorone diisocyanate, blocked cycloaliphatic polyisocyanates or carbonylbiscaprolactam to increase the splice resistance of strings, in particular of trimmer strings or Mähfäden.