POLYAMIDES WITH PHOSPHORUS AND AL-PHOSPHONATES

Description

[0001] The invention relates to thermoplastic molding compositions containing A) 10 to 98.5 wt.% of a thermoplastic polyamide, B) 1 to 20 wt.% of red phosphorus, C) 0.5 to 15 wt.% of an aluminum salt of phosphonic acid, D) 0 to 55 wt.% of a fibrous or particulate filler or mixtures thereof, E) 0 to 30 wt.% of other additives, where the sum of the weight percentages A) to E) is 100%.

[0002] Furthermore, the present invention relates to flame-retardant molding compositions made from these polyamide mixtures and to the use of such molding compositions for producing fibers, films and molded articles and to the molded articles, fibers and films of any kind obtainable thereby.

[0003] Red phosphorus has long been known as an extremely effective flame retardant, especially for glass-fiber-reinforced polyamides and a number of other plastics. However, for a wide range of applications, it is necessary to impart not only high flame retardancy to plastic molding compounds. Rather, especially for demanding applications in the electrical and electronics sector, the coordination of material properties toward a balanced product profile consisting of high flame retardancy combined with excellent mechanical and glow-wire resistance is becoming increasingly important.

[0004] Especially for thin-walled components, such as those equipped with highly stressed snap fasteners, it is important that the materials used have good elongation values, but also high load-bearing capacity in terms of their toughness.

[0005] Halogen-free, flame-retardant, glass-fiber-reinforced polyamide compounds generally exhibit reduced mechanical properties, particularly in terms of elongation at break and impact strength, compared to similar compositions without flame retardant. However, the addition of impact modifiers based on olefin (co)polymers often leads to significantly reduced flame retardant properties, particularly inadequate glow-wire resistance.

[0006] From WO 2013 / 083247, flame retardants based on phosphites are known, which in combination with dialkylphosphinic acids can generally be used for thermoplastics.

[0007] However, the mechanics and the glow wire test need improvement.

[0008] WO 2014 / 135256 A1, EP 3 034 553 A1, WO 2013 / 083247 A1 and WO 2014 / 170148 A1 disclose special flame-retardant polymers.

[0009] The present invention was therefore based on the object of providing halogen-free flame-retardant thermoplastic molding compounds which, by adding Al phosphites of different composition to red phosphorus, achieve effective flame retardancy - in particular glow-wire resistance - and improved mechanical properties.

[0010] Accordingly, the molding compositions defined at the outset have been found. Preferred embodiments can be found in the subclaims.

[0011] As component A), the molding compositions according to the invention contain 10 to 98.5, preferably 20 to 97.5 and in particular 30 to 80 wt.% of at least one polyamide.

[0012] The polyamides of the molding compositions according to the invention generally have a viscosity number of 90 to 350, preferably 110 to 240 ml / g, determined in a 0.5 wt.% solution in 96 wt.% sulfuric acid at 25°C according to ISO 307.

[0013] Semi-crystalline or amorphous resins having a molecular weight Mw (weight average) of at least 5,000, as described, for example, in American patents 2,071,250, 2,071,251, 2,130,523, 2,130,948, 2,241,322, 2,312,966, 2,512,606 and 3,393,210, are preferred.

[0014] Examples of these are polyamides derived from lactams with 7 to 13 ring members, such as polycaprolactam, polycapryllactam and polylaurolactam, as well as polyamides obtained by reacting dicarboxylic acids with diamines.

[0015] Suitable dicarboxylic acids include alkanedicarboxylic acids with 6 to 12, particularly 6 to 10, carbon atoms, and aromatic dicarboxylic acids. Examples include adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and terephthalic and / or isophthalic acid.

[0016] Particularly suitable diamines are alkanediamines with 6 to 12, in particular 6 to 8 carbon atoms and m-xylylenediamine (e.g. Ultramid ®< X17 from BASF SE, a 1:1 molar ratio of MXDA with adipic acid), di-(4-aminophenyl)methane, di-(4-aminocyclohexyl)methane, 2,2-di-(4-aminophenyl)propane, 2,2-di-(4-aminocyclohexyl)propane or 1,5-diamino-2-methylpentane.

[0017] Preferred polyamides are polyhexamethylene adipamide, polyhexamethylene sebacamide and polycaprolactam as well as copolyamides 6 / 66, in particular with a proportion of 5 to 95 wt.% of caprolactam units (e.g. Ultramid ®< C31 from BASF SE).

[0018] Further suitable polyamides are obtainable from ω-aminoalkylnitriles such as aminocapronitrile (PA 6) and adiponitrile with hexamethylenediamine (PA 66) by so-called direct polymerization in the presence of water, as described, for example, in DE-A 10313681, EP-A 1198491 and EP 922065.

[0019] Also worth mentioning are polyamides obtainable, for example, by condensing 1,4-diaminobutane with adipic acid at elevated temperatures (polyamide 4,6). Production processes for polyamides of this structure are described, for example, in EP-A 38 094, EP-A 38 582, and EP-A 39 524.

[0020] Also suitable are polyamides obtainable by copolymerizing two or more of the aforementioned monomers, or mixtures of several polyamides, with any desired mixing ratio. Blends of polyamide 66 with other polyamides, especially copolyamide 6 / 66, are particularly preferred.

[0021] Furthermore, semi-aromatic copolyamides such as PA 6 / 6T and PA 66 / 6T, whose triamine content is less than 0.5, preferably less than 0.3 wt. %, have proven particularly advantageous (see EP-A 299 444). Further high-temperature-resistant polyamides are known from EP-A 19 94 075 (PA 6T / 6I / MXD6).

[0022] The preferred semi-aromatic copolyamides with a low triamine content can be prepared by the processes described in EP-A 129 195 and 129 196.

[0023] The following non-exhaustive list contains the polyamides A) mentioned as well as other polyamides within the meaning of the invention and the monomers contained therein. AB polymers:

[0024] PA 6ε-caprolactam PA 7önantholactam PA 8capryllactam PA 99-aminopelargonic acid PA 1111-aminoundecanoic acid PA 12laurinlactam AA / BB polymers PA 46tetramethylenediamine, adipic acid PA 66hexamethylenediamine, adipic acid PA 69hexamethylenediamine, azelaic acid PA 610Hexamethylenediamine, sebacic acid PA 612Hexamethylenediamine, decanedicarboxylic acid PA 613Hexamethylenediamine, undecanedicarboxylic acid PA 12121,12-dodecanediamine, decanedicarboxylic acid PA 13131,13-diaminotridecane, undecanedicarboxylic acid PA 6THexamethylenediamine, terephthalic acid PA 9T1,9-nonandiamine, terephthalic acid PA MXD6m-Xylylenediamine, Adipic acid PA 6I Hexamethylenediamine, Isophthalic acid PA 6-3-T Trimethylhexamethylenediamine, Terephthalic acid PA 6 / 6T (see PA 6 and PA 6T) PA 6 / 66 (see PA 6 and PA 66) PA 6 / 12 (see PA 6 and PA 12) PA 66 / 6 / 610 (see PA 66, PA 6 and PA 610) PA 6I / 6T (see PA 6I and PA 6T) PA PACM 12 Diaminodicyclohexylmethane, Dodecanedioic acid PA 6I / 6T / PACM like PA 6I / 6T + Diaminodicyclohexylmethane PA 12 / MACMIL Laurinlactam,Dimethyl-diaminodicyclohexylmethane, isophthalic acid PA 12 / MACMTLaurine lactam, dimethyl-diaminodicyclohexylmethane, terephthalic acid PA PDA-TPhenylenediamine, terephthalic acid, PA4101,4-tetramethylenediamine, sebacic acid PA5101,5-pentamethylenediamine, sebacic acid PA10T1,10-decanediamine, terephthalic acid

[0025] As component B), the molding compositions according to the invention contain 1 to 50, in particular 1 to 20, preferably 1 to 10, and especially 2 to 8 wt.% red phosphorus. A preferred halogen-free flame retardant B) is elemental red phosphorus, especially in combination with glass fiber-reinforced molding compositions, which can be used in untreated form.

[0026] Particularly suitable, however, are preparations in which the phosphorus is coated on the surface with low-molecular-weight liquid substances such as silicone oil, paraffin oil, or phthalic acid esters (especially dioctyl phthalate, see EP 176 836) or adipic acid, or with polymeric or oligomeric compounds, e.g., with phenolic resins or aminoplasts, as well as polyurethanes (see EP-A 384 232, DE-A 196 48 503). Such so-called desensitizing agents are generally present in amounts of 0.05 to 5 wt.%, based on 100 wt.% B).

[0027] Concentrates of red phosphorus, e.g., in a polyamide A) or elastomers E), are also suitable as flame retardants. Polyolefin homopolymers and copolymers are particularly suitable as concentrate polymers. However, if no polyamide is used as the thermoplastic, the proportion of concentrate polymer should not exceed 35 wt.%, based on the weight of components A) to E) in the molding compositions according to the invention. Preferred concentrate compositions are

[0028] 30 to 90% by weight, preferably from 45 to 70% by weight of a polyamide A) or elastomers (E), 10 to 70% by weight, preferably from 30 to 55% by weight of red phosphorus (B).

[0029] The polyamide used for the batch can be different from A) or preferably the same as A) so that incompatibilities or melting point differences do not have a negative effect on the molding compound.

[0030] The average particle size (d 50 ) of the phosphorus particles distributed in the molding compositions is preferably in the range from 0.0001 to 0.5 mm; in particular from 0.001 to 0.2 mm.

[0031] As component C), the molding compositions according to the invention contain 0.5 to 15, preferably 0.5 to 13 and in particular 1 to 10 wt.% of at least one aluminum salt of a phosphonic acid.

[0032] Phosphonic acid is the compound with the molecular formula H3PO3 [CAS No. 13598-36-2]. The salts of phosphonic acid are called phosphonates. Phosphonic acid can exist in two tautomeric forms: the trivalent form has a free electron pair on the phosphorus atom, and the tetravalent form has a doubly bonded oxygen atom to the phosphorus atom (P=O). The tautomeric equilibrium lies entirely on the side of the form with the doubly bonded oxygen atom.

[0033] According to A. F. Holleman and E. Wiberg, Textbook of Inorganic Chemistry, 101st edition. Walter de Gruyter, Berlin / New York 1995, ISBN 3-11-012641-9, p. 764, the terms "phosphorous acid" and "phosphite" should only be used for the trivalent forms.

[0034] Even in today's literature, the terms "phosphorous acid" or "phosphites" are also used for the four-bonded forms with doubly bonded oxygen to the phosphorus, so that the terms phosphonic acid and phosphorous acid or phosphonates and phosphites are used synonymously.

[0035] Preferred components C) are composed of [Al 2 (HPO 3 ) 3 ·x (H 2 O) q (Formula I) with q = 0 to 4 or Al 2 M a (HPO 3 ) b (OH) cx (H 2 O) d (Formula II) with M alkali metal ions a = 0.01 to 1.5 b = 2.63 to 3.5 c = 0 to 2 d = 0 to 4 or Al 2 (HPO 3 ) e (H 2 PO 3 ) fx (H 2 O) q (formula III) with e = 2 to 2.99 f = 2 to 0.01 g = 0 to 4 or mixtures of aluminum phosphites and aluminum oxide of the type Al 2 (HPO 3 ) 3 x 0.1 to 30 Al 2 O 3 x 0 to 50 H 2 O (formula IV) or primary aluminum phosphonate [Al(H 2 PO 3 ) 3 ] (formula V) or basic aluminum phosphonate [Al(OH)H 2 PO 3 ) x·2H 2 O] (formula VI) or mixtures thereof.

[0036] Preferred molding compositions contain as component C) compounds of the formula II in which M is sodium and / or potassium.

[0037] Preferred compounds of formula I are secondary aluminum phosphonate [Al 2 (HPO 3 ) 3 ] (formula Ia) or aluminum phosphonate tetrahydrate [Al 2 (HPO 3 ) 3 ·4H 2 O] (formula Ib) or mixtures thereof.

[0038] Preferred compounds of formula IV are composed of mixtures of aluminum phosphites and aluminum oxide of the type Al 2 (HPO 3 ) 3 x 0.2 to 20 Al 2 O 3 x 0 to 50 H 2 O (formula IV) and very particularly preferably Al 2 (HPO 3 ) 3 x 1 to 3 Al 2 O 3 x 0 to 50 H 2 O.

[0039] Preferred compounds C) of formula II are those in which a is 0.15 to 0.4, b is 2.80 to 3 and c is 0.01 to 0.1.

[0040] Further preferred components C) are composed of compounds of formula III in which e is 2.834 to 2.99 and f is 0.332 to 0.03 and g is 0.01 to 0.1.

[0041] Particularly preferred compounds C) are those of formula II or III, where a, b and c as well as e and f can only assume such numbers that the corresponding aluminum salt of the phosphonic acid as a whole is uncharged.

[0042] Particularly preferred are aluminum phosphites with CAS numbers 15099-32-8, 119103-85-4, 220689-59-8, 56287-23-1, 156024-71-4 (secondary aluminum phosphonate tetrahydrate), 71449-76-8 (secondary aluminum phosphonate) and 15099-32-8

[0043] The described aluminum salts of phosphonic acid can be used individually or in mixtures.

[0044] The aluminum phosphites preferably have particle sizes of 0.2 to 100 µm, the particle size distribution of which can be determined by conventional laser diffraction analysis methods.

[0045] The preferred aluminum phosphites are typically prepared by reacting an aluminum source with a phosphorus source in a solvent at 20 to 200 °C for a period of up to 4 days. The aluminum source and phosphorus source are mixed, heated under hydrothermal conditions or at reflux, filtered, washed, and dried. The preferred solvent is water.

[0046] The preparation of the aluminum salts of phosphonic acid used according to the invention as component C) can be found, for example, in WO 2013 / 083247.

[0047] Fibrous or particulate fillers D) which may be mentioned are carbon fibers, glass fibers, glass beads, amorphous silica, calcium silicate, calcium metasilicate, magnesium carbonate, kaolin, chalk, powdered quartz, mica, barium sulfate and feldspar, which can be used in amounts of 0 to 55, preferably 1 to 50 wt.%, in particular 5 to 40 wt.%.

[0048] Preferred fibrous fillers include carbon fibers, aramid fibers, and potassium titanate fibers, with glass fibers in the form of E-glass being particularly preferred. These can be used as rovings or chopped glass in commercially available forms.

[0049] The fibrous fillers can be surface-treated with a silane compound to improve compatibility with the thermoplastics.

[0050] Suitable silane compounds are those of the general formula (X-(CH 2 ) n ) k -Si-(OC m H 2m+1 ) 4-k in which the substituents have the following meaning: no integer from 2 to 10, preferably 3 to 4 my integer from 1 to 5, preferably 1 to 2 no integer from 1 to 3, preferably 1

[0051] Preferred silane compounds are aminopropyltrimethoxysilane, aminobutyltrimethoxysilane, aminopropyltriethoxysilane, aminobutyltriethoxysilane and the corresponding silanes which contain a glycidyl group as substituent X.

[0052] The silane compounds are generally used in amounts of 0.01 to 2, preferably 0.025 to 1.0 and in particular 0.05 to 0.5 wt.% (based on D) for surface coating.

[0053] Needle-shaped mineral fillers are also suitable.

[0054] For the purposes of the invention, acicular mineral fillers are understood to mean mineral fillers with a pronounced acicular character. An example is acicular wollastonite. The mineral preferably has an L / D (length / diameter) ratio of 8:1 to 35:1, more preferably 8:1 to 11:1. The mineral filler may optionally be pretreated with the aforementioned silane compounds; however, pretreatment is not absolutely necessary.

[0055] Other fillers include kaolin, calcined kaolin, wollastonite, talc and chalk, precipitated calcite, as well as platelet- or needle-shaped nanofillers, preferably in amounts between 0.1 and 10%. Mica, boehmite, bentonite, montmorillonite, vermicullite, needle-shaped zinc oxide, and hectorite are preferred for this purpose. To ensure good compatibility of the platelet-shaped nanofillers with the organic binder, the platelet-shaped nanofillers are organically modified according to the state of the art. The addition of the platelet- or needle-shaped nanofillers to the nanocomposites according to the invention leads to a further increase in mechanical strength.

[0056] As component E), the molding compositions may contain further additives in amounts of 0 to 30, preferably 0 to 25 wt.%.

[0057] In this case, rubber-elastic polymers (often also referred to as impact modifiers, elastomers or rubbers) are used in amounts of 1 to 15, preferably 1 to 10, in particular 1 to 8 wt.%.

[0058] In general, these are copolymers which are preferably composed of at least two of the following monomers: ethylene, propylene, butadiene, isobutene, isoprene, chloroprene, vinyl acetate, styrene, acrylonitrile and acrylic or methacrylic acid esters with 1 to 18 C atoms in the alcohol component.

[0059] Such polymers are described, for example, in Houben-Weyl, Methods of Organic Chemistry, Vol. 14 / 1 (Georg-Thieme-Verlag, Stuttgart, 1961), pages 392 to 406 and in the monograph by CB Bucknall "Toughened Plastics" (Applied Science Publishers, London, 1977).

[0060] Some preferred types of such elastomers are presented below: Preferred component E) are impact modifiers based on ethylene copolymers, which are composed of: E 1 ) 40 to 98 wt.%, preferably 50 to 94.5 wt.% ethylene E 2 ) 2 to 40 wt.%, preferably 5 to 40 wt.% of a (meth)acrylate having 1 to 18 C atoms, or / and E 3 ) 0 to 20 wt.%, preferably 0.05 to 10 wt.% of functional monomers selected from the group of ethylenically unsaturated mono- or dicarboxylic acids or carboxylic acid anhydrides or epoxy groups or mixtures thereof, the sum of the weight percentages E 1 ) to E 3 ) being 100% or an ethylene-(meth)acrylic acid copolymer which is neutralized with zinc up to 72%.

[0061] Particularly preferred are ethylene copolymers composed of: E 1 ) 50 to 69.9% by weight of ethylene E 2 ) 30 to 40% by weight of a (meth)acrylate having 1 to 18 C atoms E 3 ) 0.1 to 10% by weight of functional monomers according to claim 1, wherein the sum of the percentages by weight E 1 ) to E 3 ) is 100%.

[0062] The proportion of functional groups E 3 ) is 0.05 to 5, preferably 0.2 to 4 and in particular 0.3 to 3.5 wt.%, based on 100 wt.% E).

[0063] Particularly preferred components E 3 ) are composed of an ethylenically unsaturated mono- or dicarboxylic acid or a functional derivative of such an acid.

[0064] In principle, all primary, secondary and tertiary C 1 -C 18 alkyl esters of acrylic acid or methacrylic acid D 2 are suitable, but esters with 1 - 12 C atoms, in particular with 2 - 10 C atoms, are preferred.

[0065] Examples include methyl, ethyl, propyl, n-, i-butyl, and t-butyl, 2-ethylhexyl, octyl, and decyl acrylates, or the corresponding esters of methacrylic acid. Of these, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.

[0066] In addition to the esters, the olefin polymers may also contain acid-functional and / or latently acid-functional monomers of ethylenically unsaturated mono- or dicarboxylic acids or monomers containing epoxy groups.

[0067] Further examples of monomers E 3 ) are acrylic acid, methacrylic acid, tertiary alkyl esters of these acids, in particular butyl acrylate and dicarboxylic acids such as maleic acid and fumaric acid or anhydrides of these acids and their monoesters.

[0068] Latent acid-functional monomers are understood to be compounds that form free acid groups under the polymerization conditions or during incorporation of the olefin polymers into the molding compositions. Examples include anhydrides of dicarboxylic acids with up to 20 carbon atoms, especially maleic anhydride, and tertiary C 1 -C 12 alkyl esters of the aforementioned acids, especially tert-butyl acrylate and tert-butyl methacrylate.

[0069] The ethylene copolymers described above can be prepared by processes known per se, preferably by random copolymerization under high pressure and elevated temperature.

[0070] The melt index of ethylene copolymers is generally in the range of 1 to 80 g / 10 min (measured at 190°C and 2.16 kg load).

[0071] The molecular weight of these ethylene copolymers is between 10,000 and 500,000 g / mol, preferably between 15,000 and 400,000 g / mol (Mn, determined by GPC in 1,2,4-trichlorobenzene with PS calibration).

[0072] Preferred commercial products are Fusabond ®< A 560, Lucalen ®< A 2910, Lucalen ®< A 3110, Nucrel 3990, Nucrel 925, Lotader AX9800, Igetabond FS 7M.

[0073] The ethylene copolymers described above can be prepared by conventional processes, preferably by random copolymerization under high pressure and elevated temperature. Such processes are generally known.

[0074] Preferred elastomers are also emulsion polymers, the preparation of which is described, for example, by Blackley in the monograph "Emulsion Polymerization." The emulsifiers and catalysts that can be used are known per se.

[0075] Particularly preferred are copolymers which do not contain units E 2 ), but the acid component E 3 ) has been neutralized with Zn. Ethylene-(meth)acrylic acid copolymers which have been neutralized with zinc up to 72% are preferred (commercially available as Surlyn®< 9520 from Dupont).

[0076] Of course, mixtures of the rubber types listed above can also be used.

[0077] Further additives E) may be included in amounts of up to 30, preferably up to 20 wt.%.

[0078] As component E), the molding compositions according to the invention may contain 0.05 to 3, preferably 0.1 to 1.5 and in particular 0.1 to 1 wt.% of a lubricant.

[0079] Preferred are Al, alkali, alkaline earth salts or esters or amides of fatty acids having 10 to 44 C atoms, preferably having 12 to 44 C atoms.

[0080] The metal ions are preferably alkaline earth and Al, with Ca or Mg being particularly preferred.

[0081] Preferred metal salts are Ca stearate and Ca montanate as well as Al stearate.

[0082] Mixtures of different salts can also be used, whereby the mixing ratio is arbitrary.

[0083] The carboxylic acids can be mono- or divalent. Examples include pelargonic acid, palmitic acid, lauric acid, margaric acid, dodecanedioic acid, behenic acid, and particularly preferred are stearic acid, capric acid, and montanic acid (a mixture of fatty acids with 30 to 40 carbon atoms).

[0084] The aliphatic alcohols can be monohydric to tetrahydric. Examples of alcohols are n-butanol, n-octanol, stearyl alcohol, ethylene glycol, propylene glycol, neopentyl glycol, and pentaerythritol, with glycerol and pentaerythritol being preferred.

[0085] The aliphatic amines can be mono- to trivalent. Examples include stearylamine, ethylenediamine, propylenediamine, hexamethylenediamine, and di(6-aminohexyl)amine, with ethylenediamine and hexamethylenediamine being particularly preferred. Preferred esters or amides are, accordingly, glycerol distearate, glycerol tristearate, ethylenediamine distearate, glycerol monopalmitate, glycerol trilaurate, glycerol monobehenate, and pentaerythritol tetrastearate.

[0086] Mixtures of different esters or amides or esters with amides in combination can also be used, whereby the mixing ratio is arbitrary.

[0087] As component E), the molding compositions according to the invention can contain 0.05 to 3, preferably 0.1 to 1.5 and in particular 0.1 to 1 wt.% of a Cu stabilizer, preferably a Cu(I) halide, in particular in a mixture with an alkali halide, preferably KI, in particular in a ratio of 1:4.

[0088] Preferred monovalent copper salts are Cu(I) complexes with PPh3, copper(I) acetate, copper(I) chloride, copper(I) bromide, and copper(I) iodide. These are present in amounts of 5 to 500 ppm copper, preferably 10 to 250 ppm, based on polyamide.

[0089] The advantageous properties are particularly obtained when the copper is present in molecular distribution in the polyamide. This is achieved by adding a concentrate containing polyamide, a salt of monovalent copper, and an alkali halide in the form of a solid, homogeneous solution to the molding compound. A typical concentrate consists, for example, of 79 to 95 wt.% polyamide and 21 to 5 wt.% of a mixture of copper iodide or bromide and potassium iodide. The copper concentration of the solid, homogeneous solution is preferably between 0.3 and 3, in particular between 0.5 and 2 wt.%, based on the total weight of the solution, and the molar ratio of copper(I) iodide to potassium iodide is between 1 and 11.5, preferably between 1 and 5.

[0090] Suitable polyamides for the concentrate are homopolyamides and copolyamides, in particular polyamide 6 and polyamide 6.6.

[0091] In principle, all compounds with a phenolic structure that have at least one sterically demanding group on the phenolic ring are suitable as sterically hindered phenols E).

[0092] Preferably, compounds of the formula in which R 1< and R 2< are an alkyl group, a substituted alkyl group or a substituted triazole group, where the radicals R 1< and R 2< can be the same or different and R 3< is an alkyl group, a substituted alkyl group, an alkoxy group or a substituted amino group.

[0093] Antioxidants of the type mentioned are described, for example, in DE-A 27 02 661 (US- 4 360 617).

[0094] Another group of preferred sterically hindered phenols are derived from substituted benzenecarboxylic acids, in particular from substituted benzenepropionic acids.

[0095] Particularly preferred compounds from this class are compounds of the formula where R 4< , R 5< , R 7< and R 8< independently of one another represent C 1 -C 8 alkyl groups, which in turn may be substituted (at least one of which is a sterically demanding group) and R 6< represents a divalent aliphatic radical having 1 to 10 C atoms, which may also have CO bonds in the main chain.

[0096] Preferred compounds corresponding to this formula are (Irganox ®< 245 from BASF SE) (Irganox ®< 259 from BASF SE)

[0097] Examples of sterically hindered phenols include: 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate], pentaerythril-tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate], distearyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, 2,6,7-trioxa-1-phosphabicyclo-[2.2.2]oct-4-yl-methyl-3,5-di-tert-butyl-4-hydroxyhydro-cinnamate, 3,5-di-tert-butyl-4-hydroxyphenyl-3,5-distearyl-thiotriazylamine, 2-(2'-Hydroxy-3'-hydroxy-3',5'-di-tert-butylphenyl)-5-chloro-benzotriazole, 2,6-di-tert-butyl-4-hydroxymethylphenol, 1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)-benzene, 4,4'-Methylene-bis-(2,6-di-tert-butylphenol), 3,5-di-tert-butyl-4-hydroxybenzyl-dimethylamine.

[0098] 2,2'-methylene-bis-(4-methyl-6-tert-butylphenyl), 1,6-hexanediol-bis-(3,5-di-tert-butyl-4-hydroxyphenyl]-propionate (Irganox ®< 259), pentaerythrityl-tetrakis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate] and N,N'-hexamethylene-bis-3,5-di-tert-butyl-4-hydroxyhydrocinnamide (Irganox ®< 1098) and the above-described Irganox ®< 245 from BASF SE, which is particularly suitable, have proven particularly effective and are therefore preferably used.

[0099] The antioxidants E), which can be used individually or as mixtures, are contained in an amount of 0.05 to 3 wt.%, preferably 0.1 to 1.5 wt.%, in particular 0.1 to 1 wt.%, based on the total weight of the molding compositions A) to E).

[0100] In some cases, sterically hindered phenols with no more than one sterically hindered group ortho to the phenolic hydroxy group have proven particularly advantageous, especially when assessing color stability when stored in diffuse light over extended periods.

[0101] As component E), the molding compositions according to the invention may contain 0.05 to 5, preferably 0.1 to 2 and in particular 0.25 to 1.5 wt.% of a nigrosine.

[0102] Nigrosines are generally understood to be a group of black or grey phenazine dyes (azine dyes) related to the indulines in various forms (water-soluble, fat-soluble, spirit-soluble), which are used in wool dyeing and printing, in the black dyeing of silk, for dyeing leather, shoe polishes, varnishes, plastics, stoving varnishes, inks and the like, as well as as microscopy dyes.

[0103] Nigrosine is obtained industrially by heating nitrobenzene, aniline, and aniline hydrochloric acid with metal, iron, and FeCl3 (the name comes from the Latin niger, meaning black).

[0104] Component E) can be used as a free base or as a salt (e.g. hydrochloride).

[0105] Further details on nigrosines can be found, for example, in the electronic encyclopedia Römpp Online, version 2.8, Thieme-Verlag Stuttgart, 2006, keyword "nigrosin".

[0106] As component E), the thermoplastic molding compositions according to the invention may contain customary processing aids such as stabilizers, oxidation inhibitors, agents against thermal decomposition and decomposition by ultraviolet light, lubricants and mold release agents, colorants such as dyes and pigments, nucleating agents, plasticizers, etc.

[0107] Examples of oxidation retarders and heat stabilizers include sterically hindered phenols and / or phosphites and amines (e.g. TAD), hydroquinones, aromatic secondary amines such as diphenylamines, various substituted representatives of these groups and mixtures thereof in concentrations of up to 1 wt.%, based on the weight of the thermoplastic molding compositions.

[0108] UV stabilizers, which are generally used in amounts of up to 2 wt.%, based on the molding compound, include various substituted resorcinols, salicylates, benzotriazoles and benzophenones.

[0109] Inorganic pigments such as titanium dioxide, ultramarine blue, iron oxide and carbon black, as well as organic pigments such as phthalocyanines, quinacridones, perylenes and dyes such as anthraquinones can be added as colorants.

[0110] Sodium phenylphosphinate, aluminum oxide, silicon dioxide and preferably talc can be used as nucleating agents.

[0111] The thermoplastic molding compositions of the invention can be produced by conventional processes, such as mixing the starting components in conventional mixing devices such as screw extruders, Brabender mills, or Banbury mills, followed by extrusion. After extrusion, the extrudate can be cooled and comminuted. Individual components can also be premixed, and then the remaining starting materials can be added individually and / or mixed. Mixing temperatures are generally between 230 and 320°C.

[0112] According to another preferred procedure, components B) to E) can be mixed with a prepolymer, compounded, and granulated. The resulting granules are then condensed in the solid phase under inert gas, continuously or discontinuously, at a temperature below the melting point of component A) until the desired viscosity is reached.

[0113] The thermoplastic molding compositions according to the invention are characterized by better flame retardancy, in particular in the glow wire test, and better mechanics.

[0114] These are therefore suitable for the production of fibers, films, and molded bodies of all kinds. Some examples are listed below: connectors, plugs, plug parts, wiring harness components, circuit boards, circuit board components, three-dimensional injection-molded circuit boards, electrical connecting elements, and mechatronic components.

[0115] The molded parts or semi-finished products to be produced according to the invention from the thermoplastic molding compositions can be used, for example, in the automotive, electrical, electronics, telecommunications, information technology, entertainment, computer industries, in vehicles and other means of transportation, in ships, spacecraft, in the home, in office equipment, sports, in medicine and generally in objects and building parts that require increased fire protection.

[0116] For the kitchen and household sector, the use of flow-improved polyamides is possible for the production of components for kitchen appliances, such as deep fryers, irons, buttons, as well as applications in the garden and leisure sector. Examples

[0117] The following components were used: Component A1:

[0118] Polyamide 66 with a viscosity number VN of 150 ml / g, measured as a 0.5 wt.% solution in 96 wt.% sulfuric acid at 25°C according to ISO 307 (Ultramid ®< A27 from BASF SE was used). Component B:

[0119] 50% concentrate of red phosphorus with an average particle size (d50) of 10 to 30 µm in an olefin polymer E1) consisting of: 59.8 wt.% ethylene, 35 wt.% n-butyl acrylate, 4.5 wt.% acrylic acid and 0.7 wt.% maleic anhydride with a melt index MFI (190 / 2.16) of 10 g / 10 min.

[0120] The copolymer was prepared by copolymerizing the monomers at elevated temperature and pressure. Component C:

[0121] Aluminum salt of phosphonic acid (prepared according to WO 2013 / 083247 A1, Example 4) Aluminum phosphite of formula (II): 2958 g of water are placed in a 16 l high-pressure stirred vessel, heated to 155 °C, and stirred. 3362 g of aluminum sulfate solution and 2780 g of sodium phosphite solution are then added simultaneously over a period of 30 minutes. The resulting suspension is drained off and filtered at 80 °C, washed with hot water, redispersed, and washed again. The filter cake is dried in a dryer at 220 °C. An inventive alkali-aluminum mixed phosphite with very high thermal stability is obtained in 85% yield.

[0122] According to atomic spectroscopy, the reaction product contains 18.3% Al, 32.0% P, 0.3% S, and 0.07% Na. The residual moisture content of 0.1% water was determined by Karl Fischer titration. Component C1V:

[0123] Aluminum diethylphosphinate (Exolit ®< OP1230 ex Clariant Produkte GmbH). Component D:

[0124] Standard chopped glass fiber for polyamides, length = 4.5mm, diameter = 10 µm Component E2:

[0125] In all examples 0.35 wt.% Irganox ®< 1098 and 0.55 wt.% commercially available calcium stearate as lubricant and 0.70 wt.% commercially available zinc oxide Component E3:

[0126] 30% concentrate of a gas black with a specific BET surface area (measured according to DIN 66131) of 180 m 2 < / g in polyamide 6. Production of the molding compounds

[0127] To demonstrate the improvements described in the invention, corresponding plastic molding compounds were produced by compounding. The individual components were mixed in a ZSK 26 twin-screw extruder (Berstorff) at a throughput of 20 kg / h and a temperature of approximately 270°C with a flat temperature profile, extruded as a strand, cooled to granularity, and granulated.

[0128] The test specimens for the investigation listed in Table 1 were injection molded on an Arburg 420C injection molding machine at a melt temperature of approximately 270°C and a mold temperature of approximately 80°C.

[0129] The test specimens for the tension tests were manufactured according to ISO 527-2: / 1993 and the test specimens for the impact strength measurements according to ISO 179-2 / 1 eA.

[0130] The MVR measurements were performed according to ISO 1133.

[0131] The flame retardancy of the molding compounds was determined according to the UL94-V method (Underwriters Laboratories Inc. Standard of Safety, "Test for Flammability of Plastic Materials for Parts in Devices and Appliances", pp. 14 to 18 Northbrook 1998).

[0132] The glow wire flammability index (GWFI) on panels was determined according to IEC 60695-2-12. The GWFI is a general suitability test for plastics in contact with live parts. It determines the highest temperature at which one of the following conditions is met in three consecutive tests: (a) no ignition of the sample, or (b) an afterburn or afterglow time ≤ 30 s after the end of the glow wire exposure time and no ignition of the substrate.

[0133] The sum of the proportions of components A) to E) in Table 1 add up to 100 wt.%. Table 1 Components (wt%) V1 #6842 (405694 67J0) V2 #8048 V3 #8179 Example 1 #5212 Example 2 #5074 Example 3 #2268 A 60.4 57.4 49.73 57.4 50.2 46.87 B+E1 12 12 10.2 10.2 E1 6 6 D 26 26 26 26 36 36 C 9 3 3 2 2 C1V 13.67 E2 1.6 1.6 1.6 1.6 1.6 1.6 E3 3.33 Analysis results Viscosity number / [cm3 / g] 154 159 158 145 - - Young's modulus / [MPa] 8325 8415 8190 8454 11154 11675 Breaking stress / [MPa] 137 117 120 136 158 162 Elongation at break / [%] 3.5 3.2 3.0 3.4 3.1 2.9 Charpy impact strength / [kJ / m2] 69 57 57 70 78 74 Charpy impact strength / [kJ / m2] 8.2 7.0 6.8 7.7 - - MVR 275°C / 5kg / [cm3 / 10 min] 30 26 14 29 18 20 UL94 / 0.8 mm V-0 nc nc V-0 V-0 V-0 UL94 / 1.6 mm V-0 nc nc V-0 V-0 V-0 GWFI960 / 1.0 mm - Burn times on 3 test specimens / sec Fulfilled 58 / 57 / 5 5 Not fulfilled >60 / >60 / >60 Not fulfilled >60 / >60 / >60 Fulfilled 39 / 38 / 47 Fulfilled 39 / 38 / 47 Fulfilled 39 / 38 / 47 V1 to V3: Comparative examples Ex 1 to Ex 3: Examples according to the invention

[0134] The data in Table 1 show that the synergistic composition according to the invention has significantly shorter burning times in the glow wire test compared to the prior art, especially for thin wall thicknesses.

Claims

1. A thermoplastic molding material comprising A) 10 to 98.5 wt% of a thermoplastic polyamide, B) 1 to 20 wt% of red phosphorus, C) 0.5 to 15 wt% of an aluminum salt of phosphonic acid, D) 0 to 55 wt% of a fibrous or particulate filler or mixtures thereof, E) 0 to 30 wt% of further additives, wherein the weight percentages A) to E) sum to 100%.

2. The thermoplastic molding material according to claim 1 comprising A) 20 to 97.5 wt% B) 1 to 10 wt% C) 0.5 to 15 wt% D) 1 to 50 wt% E) 0 to 25 wt%, wherein the weight percentages A) to E) sum to 100%.

3. The thermoplastic molding material according to claims 1 and 2, in which the component C) is constructed from         [Al2(HPO3)3·x (H2O)q     (formula I) where q = 0 to 4 or         Al2Ma(HPO3)b(OH)c x (H2O)d     (formula II) where M represents alkali metal ions a = 0.01 to 1.5 b = 2.63 to 3.5 c = 0 to 2 d = 0 to 4 or         Al2(HPO3)e(H2PO3)f x (H2O)9     (formula III) where e = 2 to 2.99 f = 2 to 0.01 g = 0 to 4 or mixtures of aluminum phosphites and aluminum oxide of the type Al2(HPO3)3 x 0.1 to 30 Al2O3 x 0 to 50 H2O (formula IV) or         primary aluminum phosphonate [Al(H2PO3)3]     (formula V) or         basic aluminum phosphonate [Al(OH)H2PO3) x·2H2O]     (formula VI) or mixtures thereof.

4. The thermoplastic molding material according to claims 1 to 3, comprising as component C) compounds of formula II in which M represents sodium and / or potassium.

5. The thermoplastic molding material according to claims 1 to 4, in which the component C) is constructed from         secondary aluminum phosphonate [Al2(HPO3)3]     (formula Ia) or         aluminum phosphonate tetrahydrate [Al2(HPO3)3·4H2O]     (formula Ib) or mixtures thereof.

6. The thermoplastic molding material according to claims 1 to 5, in which the component C) is constructed from mixtures of aluminum phosphites and aluminum oxide of the type Al2(HPO3)3 x 0.2 to 20 Al2O3 * 0 to 50 H2O (formula IV).

7. The thermoplastic molding material according to claims 1 to 6, in which the component C) is constructed from compounds of formula II in which a is 0.15 to 0.4 and b is 2.80 to 3 and c is 0.01 to 0.1.

8. The thermoplastic molding material according to claims 1 to 7, in which the component C) is constructed from compounds of formula III in which e is 2.834 to 2.99 and f is 0.332 to 0.03 and g is 0.01 to 0.1.

9. The use of the thermoplastic molding material according to claims 1 to 8 for the production of fibers, films and moldings.

10. A fiber, film or molding obtainable from the thermoplastic molding material according to claims 1 to 8.