Flame-retardant polyamide molding compounds for the insulation of electrical components

Description

[0001] The present invention relates to flame-resistant polyamide molding compounds with a low phosphorus content.

[0002] EP 150511 A1 discloses powdered polyamide compositions containing an alkyl phosphonate for use in 3D printing.

[0003] EP 3127937 A1 demonstrates the effectiveness of metal phonophineates for the flame retardancy of polyamides. According to the verbal evaluation of the examples, the addition of melamine cyanurate should be avoided.

[0004] EP 1731559 A1 proposes a phosphorus compound in combination with melamine cyanurate and an alcohol as a flame retardant for polyamide. These achieve a UL 94 classification of V-0; however, comparative tests of the present invention show increased mass loss due to migration. Neither this mass loss nor the elongation at break of the compositions were considered in EP 1731559 A1.

[0005] In US 2018 / 003771 A1, it is recommended that polyamides be flame-retardant exclusively with melamine cyanurate and a polyol. Mechanical requirements are not disclosed.

[0006] The object of the present invention was to provide polyamide molding compounds which are very flame-resistant with a low phosphorus content and suffer only a very low mass loss at high temperatures, while the molding compounds should be characterized by a high elongation at break.

[0007] Surprisingly, it was found that flame retardants with a low content of phosphorus-containing compounds can be used to advantage in polyamide molding compounds.

[0008] The present invention relates to a polyamide molding compound comprising: (A) a polyamide matrix containing one or more polyamides with at least 8 carbons per amide unit; (B) a flame retardant composition containing: (B1) at least one metal-free aryl phosphate; (B2) at least one aryl phosphonate; (B3) a carbo-polyalcohol; (B4) melamine cyanurate; (B5) optional, non-phosphorus flame retardants, wherein the phosphorus content of the total flame retardant composition is 0.5 to 1.5 wt.%, preferably 0.75 to 1.25 wt.% based on the polyamide molding compound.

[0009] Another object of the present invention is the use of the polyamide molding compound according to the invention for the manufacture of a component.

[0010] Another object of the present invention is a method for insulating current-carrying components.

[0011] Another object of the present invention is a hybrid component comprising a coated metal body, wherein the coating comprises a polyamide molding compound.

[0012] Another object of the invention is the use of the hybrid components for the transmission of electric current, preferably in high and low voltage systems, more preferably in high voltage systems.

[0013] The polyamide molding compounds according to the invention, the hybrid components containing the molding compounds according to the invention, and the uses according to the invention are described below by way of example, without the invention being limited to these exemplary embodiments. Where ranges, general formulas, or classes of compounds are specified below, these are intended to include not only the corresponding ranges or groups of compounds that are explicitly mentioned, but also all sub-ranges and subgroups of compounds that can be obtained by removing individual values ​​(ranges) or compounds. Where documents are cited within the scope of this description, their content is intended to be fully incorporated into the disclosure of the present invention. Where percentages are given below, they are, unless otherwise specified, percentages by weight.Unless otherwise stated, percentages in composition data refer to the total composition. Average values ​​given below are mass averages (weight averages) unless otherwise stated. Measured values ​​given below were determined at a pressure of 101325 Pa and a temperature of 25 °C unless otherwise stated.

[0014] The scope of protection includes commercially customary packaging and preparation of the products according to the invention, both as such and in any comminutionary forms, insofar as these are not defined in the claims.

[0015] The potentially different units of the polyamides are statistically distributed. Statistical distributions can be structured block-wise with any number of blocks and any sequence, or they can be randomized. They can also be structured alternately or form a gradient along the polymer chain; in particular, they can also form all mixed forms, in which groups of different distributions may follow one another. Specific designs may impose restrictions on the statistical distributions. For all regions not affected by the restriction, the statistical distribution remains unchanged.

[0016] One advantage of the polyamide molding compounds according to the invention is that they are very well fire-resistant, they have a fire classification according to UL94 of V-0.

[0017] Another advantage of the polyamide molding compounds according to the invention is that they have a high elongation at break.

[0018] Another advantage of the polyamide molding compounds according to the invention is that after storage at high temperature for a longer period of time, only a very low migration of low molecular weight components to the surface (efflorescence, mass loss) takes place.

[0019] Another advantage of the polyamide molding compounds according to the invention is that there is no loss of flame protection due to mass loss through migration.

[0020] Another advantage is the particularly good adhesion of the polyamide molding compounds according to the invention to metallic surfaces. Polyamide matrix (A)

[0021] Preferably, the polyamides of the polyamide matrix (A) have, on average across the polymer, 8 to 16 carbon atoms, more preferably 9 to 14, and particularly preferably 10 to 12 carbon atoms per amide unit. More preferably, the polyamides of the polyamide matrix (A) have at least 8 carbon atoms per amide unit in all monomer units.

[0022] Polyamides can be homopolymers, copolymers, or blends of different polyamides. The differences between polyamides can arise, for example, from different monomers used in the polymerization, different molar mass distributions (which can manifest as different viscosities), or different end groups.

[0023] Preferably, the polyamides are selected from PA 8, PA 9, PA 10, PA 11, PA 12, PA 6.10, PA 6.12, PA 6.14, PA 8.10, PA 9.10, PA 9.12, PA 10.10, PA 10.12, PA 12.12, PA 6.16, PA 10.16; more preferably, PA 6.12, PA 10.10, PA 10.12, PA 11 and PA 12; particularly preferably PA 11 and PA 12.

[0024] Preferably, the polyamide molding compound contains no other polyamide besides the polyamides of the polyamide matrix (A). Flame retardant composition (B)

[0025] Preferably, the flame retardant composition of the polyamide molding compound according to the invention contains 15 to 55 wt.%, preferably 25 to 50 wt.%, more preferably 30 to 45 wt.% melamine cyanurate (B4); 10 to 30 wt.%, preferably 15 to 25 wt.%, more preferably 17 to 23 wt.% carbo-polyalcohol (B3); 5 to 30 wt.%, preferably 7 to 25 wt.%, more preferably 13 to 23 wt.% arylphosphonate (B2); 5 to 30 wt.%, preferably 7 to 25 wt.%, more preferably 13 to 23 wt.% metal-free aryl phosphate (B1); 0 to 15 wt.%, preferably 3 to 12 wt.%, more preferably 5 to 10 wt.% of a non-phosphorus-containing flame retardant (B5); where the sum of (B1), (B2), (B3), (B4) and (B5) equals 100 percent by weight of component (B).

[0026] Preferably, in the flame retardant composition of the polyamide molding compound according to the invention, the mass ratio of (B1) to (B2) is 0.25 to 4, preferably 0.33 to 3, more preferably 0.5 to 2, and particularly preferably 0.75 to 1.5.

[0027] The non-phosphorus flame retardants(B5) differ from the flame retardants according to B3 and B4. Preferred are urea and urea derivatives, magnesium hydroxides, aluminum hydroxides, aluminum sulfate, borax, boric acid and salts of boric acid (e.g., zinc borate), ammonium sulfate, and calcium hydroxides. Halogenated flame retardants may also be added.

[0028] Preferably, the non-phosphorus flame retardants (B5) do not contain halogenated substances.

[0029] Under Melanmine cyanurate(B4) also includes melamine condensation products, melem, melam, melon, but preferably refers exclusively to melamine cyanurate (CA-RN 37640-57-6) itself. The melamine cyanurate is used in powder form. Preferably, it has a particle size D50, measured by laser diffraction with a laser granulometer according to BS ISO 13320-1, edition 2000-03-15, of 0.5 to 100 µm, more preferably of 0.6 to 50 µm, particularly preferably of 0.7 to 25 µm, most preferably of 0.8 to 5 µm, and most preferably of 0.9 to 4 µm. The measurement is preferably carried out with a Cilas laser granulometer type 715 / 920.

[0030] Small particle sizes are preferred because they give the molded parts a smoother surface.

[0031] The Carbo-polyalcohol(B3) is preferably a hydrocarbon which is substituted with at least 3, preferably at least 4, more preferably at least 5, further more preferably at least 6 hydroxy groups and optionally contains ether groups, preferably at least one ether group.

[0032] The carbo-polyalcohol is more preferably selected from a triol such as trimethylolpropane or glycerol, or a derivative thereof such as di-trimethylolpropane or diglycerol (formed by mono-etherification of two molecules of the aforementioned compounds), or a tetrol such as erythritol, pentaerythritol, or a derivative thereof containing ether groups such as di- or tripentaerythritol, a pentol such as xylitol or arabitol, a hexol such as mannitol, sorbitol, or the like; in addition, higher adducts of the aforementioned molecules can also be used, for example, a branched or hyperbranched polyglycerol; mixtures of polyols can, of course, also be used. Erythritol, pentaerythritol, or di- or tripentaerythritol, in particular di-pentaerythritol, are more preferred.

[0033] Arylphosphonate(B2) within the meaning of the invention are polymeric or oligomeric with at least 3 repeating units, preferably 3 identical repeating units, and contain aromatic residues in the backbone of the molecules.

[0034] The arylphosphonate preferentially has the repeating unit according to formula (III). wherein R1 independently represents an alkyl group with 1 to 4 carbon atoms, preferably methyl, and wherein BAr independently represents an aromatic group, preferably an at least dinuclear aromatic group, more preferably biphenyls or 4,4'-(propane-2,2-diyl)diphenyls.

[0035] The arylphosphonate preferably has the -BAr-OH group as end groups.

[0036] In particular, the arylphosphonate preferably has the repeating unit according to formula (IV). This means that the arylphosphonate preferentially has bisphenol A end groups.

[0037] The arylphosphonate preferably has an MVR (melt volume rate) of less than 100 ml / 10 min and more preferably an MVR of at least 10 ml / 10 min, further more preferably of at least 25 ml / 10 min, particularly preferably of at least 50 ml / 10 min and particularly preferably of 65 to 90 ml / 10 min (measured at 240°C and a coating mass of 1.2 kg, according to ISO 1133).

[0038] The metal-free Aryl phosphate (B1) preferably has at least 2 phosphate groups. More preferably, the metal-free aryl phosphate has at least one unit of formula (I), preferably 1 to 2 of these units. and at least two units, preferably two to three units, of formula (II), on, wherein the units of formulas (I) and (II) are present alternately, wherein the number of units according to formula (II) is always 1 greater than that of formula (I), where Ar stands for ortho-, meta-, para-phenylene, naphtylene, biphenylene, where Ph stands for a phenyl group, optionally substituted arbitrarily with C1 to C4 alkyl groups.

[0039] Preferably, the metal-free aryl phosphate has phenyl residues as end groups, which can be substituted arbitrarily with C1 to C4 alkyl residues.

[0040] The metal-free aryl phosphate more preferably exhibits structural elements of formula (V) on.

[0041] Particularly preferentially, the metal-free aryl phosphate has the structure of formula (VI) on, where Ar stands for meta- or para-phenylene and Ph stands for phenyl.

[0042] Preferably, Ar does not represent a 4,4'-(propane-2,2-diyl)diphenylene residue.

[0043] Preferably, the flame retardant composition contains no polyphosphates, no reaction products of melamine with polyphosphoric acid, and no derivatives of phosphorus(III) and / or phosphorus(I) acid.

[0044] Preferably, the flame retardant composition contains no other phosphorus-containing components besides components (B1) and (B2).

[0045] A preferred combination of the flame retardant composition (B) is: at least one metal-free aryl phosphate (B1) comprising at least one unit of formula (I), preferably 1 to 2 of these units and at least two units, preferably two to three units, of formula (II), exhibiting, wherein the units of formulas (I) and (II) are present alternately, the number of units according to formula (II) always being 1 greater than that of formula (I), where Ar stands for ortho-, meta-, para-phenylene, naphtylene, biphenylene, but not for a 4,4'-(propane-2,2-diyl)diphenylene residue, where Ph stands for a phenyl residue, optionally arbitrarily substituted with C1 to C4 alkyl residues; at least one arylphosphonate (B2) which has the repeating unit according to formula (IV). and as end group bisphenol A; carbo-polyalcohol (B3), which is composed of at least 3, preferably at least 4,more preferably at least 5, further more preferably at least 6 hydroxy groups is substituted and optionally contains ether groups, preferably has at least one ether group; melamine cyanurate (B4) and optionally, non-phosphorus-containing flame retardants (B5) selected from urea and urea derivatives, magnesium hydroxides, aluminum hydroxides, aluminum sulfate, borax, boric acid and salts of boric acid (e.g. zinc borate), ammonium sulfate, calcium hydroxides, optionally also halogen-containing flame retardants.

[0046] A more preferred combination of flame retardant composition (B) is: at least one metal-free aryl phosphate (B1) which structural elements of formula (V) exhibiting, where Ar stands for ortho-, meta-, para-phenylene, naphtylene, biphenylene, but not for a 4,4'-(propane-2,2-diyl)diphenylene residue, where Ph stands for a phenyl residue, optionally arbitrarily substituted with C1 to C4 alkyl residues; at least one arylphosphonate (B2) which exhibits the repeating unit according to formula (IV) and as the end group bisphenol A; carbo-polyalcohol (B3), which is composed of at least 3, preferably at least 4,more preferably at least 5, further more preferably at least 6 hydroxy groups substituted and optionally containing ether groups, preferably having at least one ether group; melanmine cyanurate (B4) with a particle size D50, measured by laser diffraction with a laser granulometer according to BS ISO 13320-1, edition 2000-03-15, from 0.5 to 100 µm, more preferably from 0.6 to 50 µm, particularly preferably from 0.7 to 25 µm, most preferably from 0.8 to 5 µm and particularly preferably from 0.9 to 4 µm; and optionally, non-phosphorus-containing flame retardants (B5) selected from urea and urea derivatives, magnesium hydroxides, aluminum hydroxides, aluminum sulfate, borax, boric acid and salts of boric acid (e.g. zinc borate), ammonium sulfate, calcium hydroxides, possibly also halogenated flame retardants; with a mass ratio of (B1) to (B2) equal to 0.25 to 4, preferably 0.33 to 3, more preferably 0.5 to 2, particularly preferably 0.75 to 1.5.

[0047] A particularly preferred combination of flame retardant composition (B) is: 5 to 30 wt% of at least one metal-free aryl phosphate (B1) having the structure of formula (VI) comprising, where Ar represents meta- or para-phenylene, where Ph represents a phenyl group, optionally substituted with C1 to C4 alkyl groups; 5 to 30 wt% of at least one arylphosphonate (B2) comprising the repeating unit according to formula (IV). and bisphenol A as the end group; 10 to 30 wt% carbo-polyalcohol (B3) substituted with at least 3, preferably at least 4, more preferably at least 5, further more preferably at least 6 hydroxy groups and preferably having at least one ether group; 15 to 55 wt% melanmine cyanurate (B4) with a particle size D50, measured by laser diffraction with a laser granulometer according to BS ISO 13320-1, edition 2000-03-15, from 0.5 to 100 µm, more preferably from 0.6 to 50 µm, particularly preferably from 0.7 to 25 µm, most preferably from 0.8 to 5 µm and particularly preferably from 0.9 to 4 µm; and 0 to 15 wt% non-phosphorus flame retardants (B5) selected from urea and urea derivatives, magnesium hydroxides, aluminium hydroxides, aluminium sulfate, borax, boric acid and salts of boric acid (e.g.Zinc borate), ammonium sulfate, calcium hydroxides; wherein the sum of (B1), (B2), (B3), (B4) and (B5) yields 100% by weight of component (B); with a mass ratio of (B1) to (B2) of 0.25 to 4, preferably 0.33 to 3, more preferably 0.5 to 2, and particularly preferably 0.75 to 1.5.

[0048] Preferably, the polyamide molding compound according to the invention contains, in addition to the phosphorus-containing flame retardants, no more than 5000 ppm, preferably no more than 1000 ppm, more preferably no more than 500 ppm, and particularly preferably no more than 250 ppm phosphorus from other sources, such as stabilizers, process aids or catalysts.

[0049] Optionally, the polyamide molding compounds according to the invention contain conventional processing aids such as stabilizers, oxidation retarders, further agents against heat decomposition and decomposition by ultraviolet light, lubricants and demolding agents, colorants such as dyes and pigments, nucleation agents, plasticizers, etc.

[0050] Optionally, the polyamide molding compounds according to the invention contain, in addition to the components described, further additives selected from one or more representatives, optionally also several of the same type, such as stabilizers, other polymers, impact modifiers, plasticizers, colorants such as pigments and dyes, processing aids.

[0051] Suitable Oxidation stabilizersThese include aromatic amines, sterically hindered phenols, hydroquinones, phosphites, phosphonites, thiosynergists, hydroxylamines, benzofuranone derivatives, acryloyl-modified phenols, etc. Such oxidation stabilizers are commercially available in a variety of types, for example under the trade names Naugard 445, Irganox 1010, Irganox 1098, Irgafos 168, P-EPQ, or Lowinox DSTDP. Generally, the molding compounds contain approximately 0.01 to approximately 2 wt%, and preferably approximately 0.1 to approximately 1.5 wt%, of oxidation stabilizers.

[0052] Furthermore, the molding compounds may also contain UV stabilizers or light stabilizers. Suitable UV stabilizersExamples of UV absorbers include organic benzophenone derivatives, benzotriazole derivatives, resorcinols, salicylates, oxalanilides, and phenyltriazines. HALS-type light stabilizers are tetramethylpiperidine derivatives. UV stabilizers and light stabilizers can be advantageously used in combination. Both are commercially available in a wide variety of types; the manufacturer's instructions should be followed regarding dosage.

[0053] Furthermore, the molding compounds may contain hydrolysis stabilizers such as monomeric, oligomeric or polymeric carbodiimides or bisoxazoline.

[0054] Other polymers that may be included as additives in the molding compounds are, for example, polyetheramides or polytetrafluoroethylene (PTFE).

[0055] Impact modifierThese are known to those skilled in the art. They contain functional groups originating from unsaturated functional compounds that have either been polymerized into the main chain or grafted onto it. The most common are EPM or EPDM rubbers, which have been radically grafted with maleic anhydride. Such rubbers can also be used together with an unfunctionalized polyolefin, such as isotactic polypropylene, as described in EP-A-0 683 210.

[0056] Plasticizers are known to those skilled in the art from Gächter / Müller, Kunststoffadditive (Plastic Additives), C. Hanser Verlag, 2nd edition, p. 296. Commonly used compounds suitable as plasticizers include, for example, esters of p-hydroxybenzoic acid with 2 to 20 carbon atoms in the alcohol component or amides of arylsulfonic acids with 2 to 12 carbon atoms in the amine component, preferably amides of benzenesulfonic acid. Among others, ethyl p-hydroxybenzoate, octyl p-hydroxybenzoate, i-hexadecyl p-hydroxybenzoate, n-octylamide toluenesulfonic acid, n-butylamide benzenesulfonic acid, and 2-ethylhexylamide benzenesulfonic acid are suitable plasticizers.

[0057] Suitable pigments and / or Dyes Examples include mixed oxides, titanium dioxide, iron oxide, zinc sulfide, ultramarine, nigrosine, organic pigments such as phthalocyanines, quinacridones, perylene, nigrosine, anthraquinones, and pearlescent pigments.

[0058] Suitable Processing aidsExamples include paraffins, fatty alcohols, fatty acid amides, stearates such as calcium stearate, paraffin waxes, montanates or polysiloxanes.

[0059] Preferably, the polyamide molding compounds according to the invention do not contain halogenated substances.

[0060] The molding compounds according to the invention have a UL94 fire classification of V0. This classification is carried out according to the guidelines of UL, but preferably according to DIN EN 60695-11-10:2014 on test specimens with dimensions of 125 mm * 13 mm * 0.8 mm, taking into account Amendment 1 (Oct. 2015) of the said standard.

[0061] The molding compounds according to the invention preferably have an elongation at break of at least 50%, more preferably at least 100%, more preferably at least 150%, and particularly preferably at least 200%. The elongation at break is measured on tensile bars of type 1A (DIN EN ISO 527-2) according to DIN EN ISO 527-1.

[0062] The molding compounds according to the invention preferably exhibit only very low migration of low-molecular-weight components after storage at high temperature for an extended period. For this purpose, test specimens with dimensions of 125 mm × 13 mm × 0.8 mm are stored at 150°C for 24 hours, and the amount of migrated material is determined. The determination method is explained in more detail in the examples. Preferably, the mass loss due to migration is less than 1.1 wt%, more preferably less than 1.0 wt%, and particularly preferably less than 0.9 wt% based on the total molding compound.

[0063] Preferably, the molding compounds according to the invention have a classification of UL94 V-0, a mass loss due to migration of less than 1.1 wt.% and an elongation at break of at least 50%.

[0064] Preferably, the polyamide molding compounds according to the invention do not contain any additives that increase electrical conductivity, in particular no conductive carbon blacks or carbon nanotubes.

[0065] A preferred polyamide molding compound contains: (A) a polyamide matrix comprising one or more polyamides having, on average over the polymer, 8 to 16 carbon atoms, more preferably 9 to 14, particularly preferably 10 to 12 carbon atoms per amide unit; (B) a flame retardant composition comprising: (B1) at least one metal-free aryl phosphate comprising structural elements of formula (V); where Ar stands for ortho-, meta-, para-phenylene, naphtylene, biphenylene, but not for a 4,4'-(propane-2,2-diyl)diphenylene residue, where Ph stands for a phenyl residue, optionally substituted arbitrarily with C1 to C4 alkyl residues; (B2) at least one arylphosphonate with repeating units according to formula (IV); and bisphenol A as the end group; (B3) a carbo-polyalcohol substituted with at least 3, preferably at least 4, more preferably at least 5, further more preferably at least 6 hydroxy groups and optionally containing ether groups, preferably having at least one ether group; (B4) melamine cyanurate with a particle size D50, measured by laser diffraction with a laser granulometer according to BS ISO 13320-1, edition 2000-03-15, from 0.5 to 100 µm, more preferably from 0.6 to 50 µm, particularly preferably from 0.7 to 25 µm, most preferably from 0.8 to 5 µm and particularly preferably from 0.9 to 4 µm; (B5) optional, non-phosphorus-containing flame retardants selected from urea and urea derivatives, magnesium hydroxides, aluminium hydroxides, aluminium sulfate, borax, boric acid and salts of boric acid (e.g. zinc borate), ammonium sulfate, calcium hydroxides, if applicable.also halogenated flame retardants; with a mass ratio of (B1) to (B2) equal to 0.25 to 4, preferably 0.33 to 3, more preferably 0.5 to 2, particularly preferably 0.75 to 1.5; . the phosphorus content of the total flame retardant composition is 0.5 to 1.5 wt.% based on the polyamide molding compound.

[0066] Another preferred polyamide molding compound contains: (A) a polyamide matrix comprising one or more polyamides selected from PA 8, PA 9, PA 10, PA 11, PA 12, PA 6.10, PA 6.12, PA 6.14, PA 8.10, PA 9.10, PA 9.12, PA 10.10, PA 10.12, PA 12.12, PA 6.16, PA 10.16; more preferably, PA 6.12, PA 10.10, PA 10.12, PA 11 and PA 12; particularly preferably PA 11 and PA 12; (B) a flame retardant composition comprising: (B1) at least one metal-free aryl phosphate comprising at least one unit of formula (I), preferably 1 to 2 of these units and at least two units, preferably two to three units, of formula (II), (B2) wherein the units of formulas (I) and (II) are present alternately, wherein the number of units according to formula (II) is always 1 greater than that of formula (I), where Ar stands for ortho-, meta-, para-phenylene, naphtylene, biphenylene, but not for a 4,4'-(propane-2,2-diyl)diphenylene residue, where Ph stands for a phenyl residue, optionally arbitrarily substituted with C1 to C4 alkyl residues; (B2) at least one arylphosphonate with repeating units according to formula (IV); and as the end group bisphenol A; (B3) a carbo-polyalcohol substituted with at least 3, preferably at least 4, more preferably at least 5, further more preferably at least 6 hydroxy groups and optionally containing ether groups, preferably having at least one ether group; (B4) melamine cyanurate; (B5) optionally, non-phosphorus-containing flame retardants selected from urea and urea derivatives, magnesium hydroxides, aluminum hydroxides, aluminum sulfate, borax, boric acid and salts of boric acid (e.g. zinc borate), ammonium sulfate, calcium hydroxides, optionally also halogen-containing flame retardants; with a mass ratio of (B1) to (B2) of 0.25 to 4, preferably 0.33 to 3, more preferably 0.5 to 2, in particular preferably 0.75 to 1.5; the phosphorus content of the total flame retardant composition is 0.5 to 1.5 wt.% based on the polyamide molding compound.

[0067] A still preferred polyamide molding compound contains: (A) a polyamide matrix comprising one or more polyamides having, on average over the polymer, 8 to 16 carbon atoms, more preferably 9 to 14, particularly preferably 10 to 12 carbon atoms per amide unit; (B) a flame retardant composition comprising: (B1) at least one metal-free aryl phosphate comprising at least one unit of formula (I), preferably 1 to 2 of these units and at least two units, preferably two to three units, of formula (II), (B2) wherein the units of formulas (I) and (II) are present alternately, wherein the number of units according to formula (II) is always 1 greater than that of formula (I), where Ar stands for ortho-, meta-, para-phenylene, naphtylene, biphenylene, but not for a 4,4'-(propane-2,2-diyl)diphenylene residue, where Ph stands for a phenyl residue, optionally arbitrarily substituted with C1 to C4 alkyl residues; (B2) at least one arylphosphonate with repeating units according to formula (IV); and as the end group bisphenol A; (B3) a carbo-polyalcohol substituted with at least 3, preferably at least 4, more preferably at least 5, further more preferably at least 6 hydroxy groups and optionally containing ether groups, preferably having at least one ether group; (B4) melamine cyanurate; (B5) optionally, non-phosphorus-containing flame retardants selected from urea and urea derivatives, magnesium hydroxides, aluminum hydroxides, aluminum sulfate, borax, boric acid and salts of boric acid (e.g. zinc borate), ammonium sulfate, calcium hydroxides, optionally also halogen-containing flame retardants; with a mass ratio of (B1) to (B2) of 0.25 to 4, preferably 0.33 to 3, more preferably 0.5 to 2, particularly preferably 0.75 to 1.5; wherein the phosphorus content of the total flame retardant composition is 0.5 to 1.5 wt.-% based on the polyamide molding compound; wherein the molding compound has a UL94 V-0 classification, a mass loss due to migration of less than 1.1 wt% and an elongation at break of at least 50%.

[0068] The present invention relates to the use of the polyamide molding compounds according to the invention for the manufacture of components, as well as the components themselves, especially for fire-protected applications in the vehicle sector, preferably as a coating, cover, film, profile, tube, corrugated tube, hollow body, seal, cladding, bracket, housing, sheathing, electrical and electronic components such as preferably current-carrying metal parts.

[0069] In the inventive method for insulating current-carrying components, the components are preferably manufactured by pressing, foaming, extrusion, coextrusion, blow molding, 3D blow molding, coextrusion blow molding, coextrusion 3D blow molding, coextrusion suction blow molding, extrusion coating, powder coating, or injection molding. Such methods are known to those skilled in the art.

[0070] Preferably, the hybrid components according to the invention comprise a coated metal body, wherein the coating comprises a polyamide molding compound containing: (A) a polyamide matrix containing one or more polyamides with at least 8 carbons per amide unit; (B) a flame retardant composition containing: (B1) at least one metal-free aryl phosphate; (B2) at least one aryl phosphonate; (B3) a carbo-polyalcohol; (B4) melamine cyanurate; (B5) optionally non-phosphorus flame retardants, wherein the phosphorus content of the total flame retardant composition is 0.5 to 1.5 wt.%, preferably 0.75 to 1.25 wt.%, based on the polyamide molding compound. The components of the polyamide molding compound are described above.

[0071] Preferably, the non-phosphorus flame retardants (B5) do not contain halogenated flame retardants. More preferably, the entire coating does not contain any halogenated substances. This offers the advantage of improved corrosion protection and better environmental compatibility; furthermore, even under extreme heat, such as in a metal fire, no halogenated substances are emitted.

[0072] Furthermore, the present invention relates to a method for manufacturing such a component. It is characterized in that the polyamide molding compound is formed into the component by an extrusion or extrusion blow molding process, an injection molding process, or a back injection molding process.

[0073] Particularly in the case of hybrid components, these can be reshaped after the metal body has been coated. It is also possible to attach further components to the hybrid parts, such as plugs and sockets, screws, and connecting elements.

[0074] During forming, the polyamide molding compounds according to the invention are advantageously characterized by their very good formability; thus, during the forming of a hybrid component, no delamination, cracking, shrinkage waves and similar effects of the coating made from the polyamide molding compound (hereinafter also referred to as polyamide coating) occur.

[0075] Its excellent formability ensures that the polyamide coating provides effective electrical insulation, particularly in high-voltage applications. In high-voltage environments, large amounts of charge are transported over extended periods. The coating with the molding compounds according to the invention is characterized by outstanding temperature stability. This manifests itself in two ways. Firstly, no significant mass loss occurs due to migration. Thus, the excellent insulating properties are maintained, both between the external environment and the current-carrying metal, and at the surface of the polyamide coating (prevention of creepage currents). Secondly, the polyamide coatings remain mechanically stable even after prolonged periods and at high temperatures, e.g., against vehicle vibrations. In particular, no cracks occur at the aforementioned forming points, which would significantly impair the insulating effect.

[0076] The hybrid components according to the invention can preferably be used in vehicles, where "vehicles" encompasses all means of transport, i.e., water, land, air, and space. The hybrid components serve, for example, for charge transfer in power supply systems, both within the power-generating component and for transfer to the recipient. Preferred applications include use in electrically powered vehicles, e.g., the series or parallel connection of energy storage systems or power generators, the transfer of charge from the energy storage or generator system to the drive unit, and the transfer of charge to other power-consuming systems, preferably in high-voltage systems.

[0077] The hybrid components according to the invention can also preferably be used in stationary systems, such as power plant plants: wind turbines, fuel or electrolysis cells, hydroelectric power plants or other power plants, or in intermediate processors such as substations, etc., or in transmission facilities such as cable and line systems in the ground, underwater or in structures, e.g. bridges, the latter being particularly exposed to weather and vibrations from use.

[0078] The phosphorus content specifications for the articles according to the invention refer to the phosphorus content as an element. Methods

[0079] Differential Scanning Calorimetry (DSC): DSC measurements were performed according to DIN EN ISO 11357-1: 2016.

[0080] Relative solution viscosity (η-rel value): The samples are dissolved in m-cresol (0.005 g / ml) at 30 °C and measured at 25.00 °C in a viscosity measuring system (LAUDA PVS or Schott AVS Pro).

[0081] The molding compounds according to the invention have a UL94 fire classification of V-0. The classification is carried out according to the UL guidelines, but preferably according to DIN EN 60695-11-10:2014 on test specimens with dimensions of 125 mm * 13 mm * 0.8 mm, taking into account Amendment 1 (Oct. 2015) of the aforementioned standard.

[0082] To determine the mass loss due to migration, a test specimen (125 mm * 13 mm * 0.8 mm) is weighed at 23°C and then thermally treated for 24 hours at 150°C in an oven according to IEC 60216-4. The specimen is then cooled for 30 minutes at 23°C and mechanically cleaned with a damp cloth containing acetone until no wipeable residue remains (mirror test). The specimen is then dried for 15 minutes at 23°C and electrostatically discharged using an ionizer. The mass loss is calculated by weighing the specimen again as the average of three samples. The negative value of this average is referred to as the mass loss due to migration.

[0083] The elongation at break was determined according to DIN EN ISO 527-1. Shoulder bars A1 according to Part 2 of the aforementioned standard were used. The measurements were taken at 23°C at a speed of 50 mm / min.

[0084] Elongation at break is of particular importance in the context of the present invention, as its use as an electrical insulator for sheathing conductors, especially in high-voltage applications, requires it to meet particularly stringent requirements. These conductors are deformed by up to 180°, and it must be ensured that the insulator is completely free of cracks, as these would act as electrical bridges. It is immediately obvious that these requirements must be met with the utmost safety, for example, in automotive applications, to avoid endangering people working in the engine compartment. Materials:

[0085] PA 6.10: medium viscosity PA 6.12: medium viscosity PA 10.12: medium viscosity PA 12: high viscosity PA 12 / 6: medium viscosity Melamine cyanurate (MC), Melapur MC 25 (BASF) Dipentaerythritol, Perstorp Fyrolflex® Sol-DP and -RDP, trademarks of ICL IP America Inc., USA ADK STAB FP-600, product of ADEKA, Polymer Additives Europe, France Disflamoll® DPK, trademark of Lanxess, Germany AFLAMMIT® PCO 900, trademark of Thor Specialities Limited, United Kingdom Amgard® CU, trademark of Lanxess, Germany Nofia® HM7000, trademark of FRX polymers, inc., USA

[0086] The stabilizer mixture contains impact modifier, stabilizer (heat and / or oxidation) and dyes / pigments. Example 1: General working instructions for the compounding of polyamide molding compounds

[0087] The molding compounds were produced on a co-rotating twin-screw extruder. The solid components were fed into the melt via the main feed, and the liquid components were fed downstream. The casing temperatures are listed in Table 1. Granulation was carried out by strand pelletizing followed by drying in a dry air chamber dryer for 12 hours at 80°C. Example 2: Production of the test specimens

[0088] The test specimens were manufactured using injection molding in accordance with DIN EN ISO 294-1 and DIN EN ISO 16396-2. The injection speed was 200 mm / s, the melt temperature was 240°C in all cases, and the corresponding mold temperatures are given in Table 1.

[0089] The following samples were produced to determine the typical material properties: Multi-purpose test specimens according to DIN EN ISO 527-2 type 1A for mechanical tests; UL94 test specimens 172 mm x 12.7 mm x 0.8 mm for UL94V and mass loss due to migration; plates for electrical measurements 130 mm x 130 mm x 1 mm. Example 3: mechanical and electrical tests

[0090] The elongation at break was determined according to DIN EN ISO 527-1.

[0091] The electrical dielectric strength was determined according to DIN EN 60243-1, AC K20 / K20. Table 1: Manufacturing parameters (temperatures in °C) of examples 2 Molding compound Injection mold Exodus 1, 4 and 5 260 80 Ex 2, 3, 7, 14-19 250 80 Ex 6 220 80 Exodus 8 and 9 260 60 Ex 10-13 240 80 Table 2: Results of the tests according to Example 3 of the test specimens according to Example 2 UL 94 Elongation at break [%] Migration [%] Dielectric strength [MV / m] Ex 1 V-0 5,9 2,64 30,7 Ex 2 V-0 51,3 0,97 28,6 Ex 3 V-0 55,1 1,84 30,9 Ex 4 V-0 75,7 2,21 31,5 Ex 5 V-0 251,6 1,51 29,1 Ex 6 V-0 320,6 3,61 33,2 Ex 7 V-0 243,6 0,79 35,3 Ex 8 V-0 230,3 1,35 28,6 Ex 9 V-0 213,5 0,89 28,5 Ex 10 V-0 198,5 2,80 31,6 Ex 11 V-0 241,7 1,30 nb* Ex 12 V-2 217,4 1,00 nb* Ex 13 V-2 179,9 0,47 nb* Ex 14 V-0 250,1 1,04 32,4 Ex 15 V-0 246,4 1,80 32,4 Ex 16 V-0 271,7 4,44 28,5 Ex 17 V-0 280,1 1,39 28,3 Ex 18 V-0 220,2 0,88 34,2 Ex 19 V-0 254,1 1,17 29,3 *nb - not determined Table 1: Composition (in wt.%) of the polyamide molding compounds according to Example 1 Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 Ex 7 Ex 8 Ex 9 Ex 10 PA 6.10 74 PA 6.12 72 PA 10.10 74 PA 10.12 74 37 PA 12 37 74 74 75 76,5 PA 12 / 6 74 Fyrolflex Sol DP phosphate 5 5 5 ADK STAB FP-600 phosphate 5 5 5 10 Fyrolflex RDP phosphate 5 Disflamoll DPK phosphate 5 AFLAMMIT PCO 900 Phosphonate 5 5 5 5 Amgard CU Phosphonate 5 5 Nofia HM7000 Phosphonate 5 5 5 5 MC 10 10 10 10 10 10 5 10 10 10 Dipentaerythritol 5 5 5 5 5 5 5 5 5 3,5 Stabilizer mixture 1 3 1 0 0 1 6 6 0 0 Table 1: cont. Ex 11 Ex 12 Ex 13 Ex 14 Ex 15 Ex 16 Ex 17 Ex 18 Ex 19 PA 6.10 PA 6.12 PA 10.10 PA 10.12 PA 12 74,5 78,5 73,5 74 74 74 74 74 74 PA 12 / 6 Fyrolflex Sol DP phosphate 7,5 5 5 8 2 ADK STAB FP-600 phosphate 5 Fyrolflex RDP phosphate 5 5 Disflamoll DPK phosphate 5 AFLAMMIT PCO 900 Phosphonate 5 Amgard CU Phosphonate Nofia HM7000 Phosphonate 10 5 2 8 5 MC 10 10 10 10 10 10 10 10 10 Dipentaerythritol 5 3,5 3,5 5 5 5 5 5 5 Stabilizer mixture 3 3 3 1 1 1 1 1 1 Examples Ex 2, Ex 7, Ex 9, Ex 14 and Ex 18 are according to the invention.

[0092] Surprisingly, the examples show that when using the aryl phosphates according to the invention, the mass loss due to migration is lower when using aryl phosphates with a phenylene group than when using the higher molecular weight aryl phosphates with a 4,4'-(propane-2,2-diyl)diphenylene group.

[0093] The examples show that the desired properties regarding flame retardancy and mass loss due to migration can only be achieved by combining metal-free aryl phosphate and aryl phosphonate. Combining metal-free aryl phosphate with alkyl phosphonates is not effective in this regard.

Claims

1. Polyamide moulding compound comprising: (A) a polyamide matrix comprising one or more polyamides having at least 8 carbon atoms per amide unit, (B) a flame retardant composition comprising: (B1) at least one metal-free aryl phosphate, (B2) at least one aryl phosphonate, (B3) a carbohydrate polyol, (B4) melamine cyanurate, (B5) optionally, non-phosphorus-containing flame retardants, wherein the content of phosphorus from the entire flame retardant composition is 0.5% to 1.5% by weight based on the polyamide moulding compound.

2. Polyamide moulding compound according to Claim 1, wherein the polyamides are selected from PA 8, PA 9, PA 10, PA 11, PA 12, PA 6.10, PA 6.12, PA 6.14, PA 8.10, PA 9.10, PA 9.12, PA 10.10, PA 10.12, PA 12.12, PA 6.16 and PA 10.16.

3. Polyamide moulding compound according to either of the preceding claims, wherein the mass ratio of (B1) to (B2) is 0.25 to 4, preferably 0.33 to 3, more preferably 0.5 to 2, particularly preferably 0.75 to 1.5.

4. Polyamide moulding compound according to any of the preceding claims, wherein the metal-free aryl phosphate (B1) contains at least one unit of formula (I), preferably 1 or 2 of said units and at least two units, preferably two or three units, of formula (II), wherein the units of formula (I) or (II) are present in alternation, wherein the number of units according to formula (II) is always 1 greater than the number of formula (I), where Ar is ortho-, meta-, para-phenylene, naphthylene or biphenylene, where Ph is a phenyl radical, optionally having any desired substitution with C1 to C4 alkyl radicals.

5. Polyamide moulding compound according to any of the preceding claims, wherein the aryl phosphonate (B2) contains the repeat unit shown in formula (III) where R1 is an alkyl radical having 1 to 4 carbon atoms and BAr is in each case independently an aromatic radical, preferably an aromatic radical having at least two rings, more preferably biphenylene or 4,4'-(propane-2,2-diyl)diphenylene.

6. Use of a polyamide moulding compound according to any of the preceding claims for the production of a component.

7. Process for insulating current-bearing components characterized in that the polyamide moulding compound according to any of Claims 1 to 5 is formed into the component in an extrusion process or blow extrusion process, an injection-moulding process or an insert moulding.

8. Hybrid component comprising a coated metal body, wherein the coating comprises a polyamide moulding compound comprising: (A) a polyamide matrix comprising one or more polyamides having at least 8 carbon atoms per amide unit, (B) a flame retardant composition comprising: (B1) at least one metal-free aryl phosphate, (B2) at least one aryl phosphonate, (B3) a carbohydrate polyol, (B4) melamine cyanurate, (B5) optionally, non-phosphorus-containing flame retardants, wherein the content of phosphorus from the entire flame retardant composition is 0.5% to 1.5% by weight based on the polyamide moulding compound.

9. Use of the hybrid components according to Claim 8 for the transmission of electric current.