DE102010023770A1 - Thermoplastic molding composition, useful e.g. to produce circuit board, comprises polyamide, flame retardant comprising phosphinic acid salt, nitrogen-containing flame retardant and optionally zinc salt, layered silicate and additive - Google Patents

Abstract

Thermoplastic molding composition (I) comprises (a) 10-99.5 wt.% of a polyamide, (b) 0.45-25 wt.% of a flame retardant combination comprising at least one phosphinic acid salt, a nitrogen-containing flame retardants and optionally a zinc salt, (c) 0.05-5 wt.% of an unmodified layered silicate, and (d) 0-70 wt.% of additives.

Description

• A) 10 bis 99,5 Gew.-% eines Polyamides
• B) 0,45 bis 25 Gew.-% einer Flammschutzmittelkombination aus mindestens einem Phosphinsäuresalz (B1), einem stickstoffhaltigen Flammschutzmittel (B2) und optional einem Zinksalz (B3)
• C) 0,05 bis 5 Gew.-% eines unmodifizierten Schichtsilikates
• D) 0 bis 70 Gew.-% weiterer Zusatzstoffe,

wobei die Summe der Gewichtsprozente der Komponenten A) bis D) 100% ergibt.The invention relates to thermoplastic molding compositions comprising

• A) 10 to 99.5 wt .-% of a polyamide
• B) 0.45 to 25 wt .-% of a flame retardant combination of at least one phosphinic acid salt (B1), a nitrogen-containing flame retardant (B2) and optionally a zinc salt (B3)
• C) 0.05 to 5 wt .-% of an unmodified layered silicate
• D) 0 to 70% by weight of further additives,

where the sum of the weight percent of components A) to D) is 100%.

Furthermore, the invention relates to the use of the molding compositions according to the invention for the production of fibers, films and moldings of any kind, and the moldings obtainable in this case.

The effectiveness of flame retardant additive mixtures of phosphinates and nitrogen synergists or melamine phosphate reaction products is essentially assessed by UL94-V fire tests. For certain applications of flame-retardant polymers in the household appliance sector, however, the glow-wire test is the primary exception IEC 60695-2-13 important, in addition, a high flame retardancy is desirable. The effectiveness of in DE-A-199 33 901 The polymer composition described in relation to the fire test according to the UL94 vertical test is satisfactory, while the efficiency in the glow wire test according to IEC 60695-2-13 is insufficient.

In addition to flame retardant properties, wear protection and a long service life of the polymer composition are important for switch applications and switching cycles, which are defined by the sliding or frictional properties (so-called tribological properties). Various wear mechanisms, such as adhesion, abrasion, surface fatigue, oxidative reaction residues, may occur singly or paired and reduce the life of the polymer composition. To determine the wear protection, there are various tribological testing devices or test methods such as the pin-disc test.

A sufficient glow wire resistance can according to the teaching of EP-A-176 25 92 be achieved by a mixture of certain fillers in defined proportions.

However, the wear behavior is in need of improvement.

It was therefore an object of the present invention to develop polymeric molding compositions based on thermoplastic polyamides, which have a high flame retardancy and good glow wire resistance with favorable sliding friction properties.

Accordingly, the molding compositions defined above were found. Preferred embodiments are given in the dependent claims.

Surprisingly, it has now been found that reinforced polymeric molding compositions based on thermoplastic polyamides, in which flame retardant mixtures of phosphinates, nitrogen-containing synergists and optionally zinc compounds are used together with phyllosilicates (talc) a specific particle size distribution, which meet the required properties in combination.

As component A), the molding compositions of the invention contain 10 to 99.5, preferably 20 to 94.5 and in particular 30 to 80 wt .-% of at least one polyamide.

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

Semicrystalline or amorphous resins having a weight average molecular weight of at least 5,000, as described, for. Tie US Pat. No. 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 described are preferred.

Examples include polyamides derived from lactams having 7 to 13 ring members, such as polycaprolactam, polycapryllactam and polylaurolactam and polyamides obtained by reacting dicarboxylic acids with diamines.

As dicarboxylic acids alkanedicarboxylic acids having 6 to 12, in particular 6 to 10 carbon atoms and aromatic dicarboxylic acids can be used. Here only adipic acid, azelaic acid, sebacic acid, dodecanedioic acid and terephthalic and / or isophthalic acid may be mentioned as acids.

4-aminophenyl, di (: Suitable diamines are particularly alkanediamines having 6 to 12, especially 6 to 8 carbon atoms and m-xylylenediamine (1 molar ratio of MXDA with adipic acid, a 1, for example Ultramid ^® X17 from BASF SE.) Are ) methane, di- (4-amino-cyclohexyl) -methane, 2,2-di- (4-aminophenyl) -propane, 2,2-di- (4-amino-cyclohexyl) -propane or 1,5-diamino -2-methyl-pentane.

Preferred polyamides are polyhexamethylene adipamide, polyhexamethylene sebacamide and polycaprolactam and copolyamides 6/66, in particular with a proportion of 5 to 95 wt .-% of caprolactam units (z. B. Ultramid ^® C31 BASF SE).

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

In addition, polyamides are also mentioned, the z. B. by condensation of 1,4-diaminobutane with adipic acid at elevated temperature are available (polyamide 4.6). Manufacturing process for polyamides of this structure are z. Tie EP-A 38 094 . EP-A 38 582 and EP-A 39 524 described.

Furthermore, polyamides which are obtainable by copolymerization of two or more of the abovementioned monomers or mixtures of a plurality of polyamides are suitable, the mixing ratio being arbitrary. Particular preference is given to mixtures of polyamide 66 with other polyamides, in particular copolyamides 6/66.

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

The production of the preferred partially aromatic copolyamides having a low triamine content can be carried out according to the methods described in US Pat EP-A 129 195 and 129 196 described method.

The following non-exhaustive list contains the mentioned, as well as other polyamides A) in the context of the invention and the monomers contained. AB-polymers: PA 4 pyrrolidone PA 6 ε-caprolactam PA 7 Ethanolactam PA 8 capryllactam PA 9 9-amine Opel argon acid PA 11 11-aminoundecanoic PA 12 laurolactam AA / BB-polymers PA 46 Tetramethylenediamine, adipic acid PA 66 Hexamethylenediamine, adipic acid PA 69 Hexamethylenediamine, azelaic acid PA 610 Hexamethylenediamine, sebacic acid PA 612 Hexamethylenediamine, decanedicarboxylic acid PA 613 Hexamethylenediamine, undecanedicarboxylic acid PA 1212 1,12-dodecanediamine, decanedicarboxylic acid PA 1313 1,13-diaminotridecane, undecanedicarboxylic acid PA 6T Hexamethylenediamine, terephthalic acid PA MXD6 m-xylylenediamine, adipic acid AA / BB-polymers 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, laurolactam PA 6I / 6T / PACM such as PA 6I / 6T + diaminodicyclohexylmethane PA 12 / MACMI Laurinlactam, dimethyldiaminodicyclohexylmethane, isophthalic acid PA 12 / MACMT Laurinlactam, dimethyl-diaminodicyclohexylmethane, terephthalic acid PA PDA-T Phenylenediamine, terephthalic acid

As component B), the molding compositions according to the invention contain from 0.45 to 25, preferably from 5 to 25 and in particular from 10 to 25,% by weight, based on A) to D) of a flame retardant combination of at least one phosphinic acid salt (B1), a nitrogen-containing flame retardant (62 ) and optionally a zinc salt (B3). Preferred compositions B) are composed of, based on 100% B,
B1) from 30 to 90, preferably from 40 to 74, 99% by weight,
B2) 10 to 50, preferably 25 to 50 wt .-%,
B3) 0 to 10, preferably 0.01 to 5 wt .-%

worin
R¹, R² gleich oder verschieden sind und C₁-C₆-Alkyl, linear oder verzweigt und/oder Aryl;
R³ C₁-C₁₀-Alkylen, linear oder verzweigt, C₆-C₁₀-Arylen, -Alkylarylen oder -Arylalkylen;
M Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K und/oder eine protonierte Stickstoffbase;
M 1 bis 4; n 1 bis 4; x 1 bis 4 bedeuten.Suitable components B1) are phosphinic acid salts of the formula (I) or / and diphosphinic acid salts of the formula (II) or their polymers.

wherein
R ¹ , R ^{2 are the} same or different and are C ₁ -C ₆ -alkyl, linear or branched and / or aryl;
R ^{3 is} C ₁ -C ₁₀ -alkylene, linear or branched, C ₆ -C ₁₀ -arylene, -alkylarylene or -arylalkylene;
M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K and / or a protonated nitrogen base;
M 1 to 4; n 1 to 4; x is 1 to 4.

Preferably, R ¹ , R ² of component B are the same or different and are methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, n-pentyl and / or phenyl.

Preferably, R ³ of component B is methylene, ethylene, n-propylene, iso-propylene, n-butylene, tert-butylene, n-pentylene, n-octylene or n-dodecylene, phenylene or naphthylene; Methyl-phenylene, ethyl-phenylene, tert-butylphenylene, methyl-naphthylene, ethyl-naphthylene or tert-butylnaphthylene; Phenyl-methylene, phenyl-ethylene, phenyl-propylene or phenyl-butylene.

R ¹ , R ² is particularly preferably methyl, ethyl and M = Al

The melamine cyanurate which is preferably suitable according to the invention (component B2) is a reaction product of preferably equimolar amounts of melamine (formula III) and cyanuric acid or isocyanuric acid (formulas IIIa and IIIb)

You get it z. B. by reaction of aqueous solutions of the starting compounds at 90 to 100 ° C. The commercially available product is a white powder with a mean particle size d ₅₀ of 1.5-7 microns.

Other suitable compounds (often also referred to as salts or adducts) are melamine, melamine borate, oxalate, phosphate prim., -Phosphate sec. And pyrophosphate sec., Neopentylglycolborsäuremelamin and polymeric melamine phosphate (CAS No. 56386-64-2).

Preference is given to melamine polyphosphate salts of a 1,3,5-triazine compound whose number n of the average degree of condensation is between 20 and 200 and the 1,3,5-triazine content of 1.1 to 2.0 mol of a 1,3,5-triazine compound from the group consisting of melamine, melam, melem, melon, ammeline, ammelide, 2-ureidomelamine, acetoguanamine, benzoguanamine and diaminophenyltriazine, per mole of phosphorus atom. Preferably, the n value of such salts is generally between 40 and 150 and the ratio of a 1,3,5-triazine compound per mole of phosphorus atom is preferably between 1.2 and 1.8. Further, the pH of a 10 wt.% Aqueous slurry of salts prepared according to EP1095030B1 generally greater than 4.5 and preferably at least 5.0. The pH is usually determined by adding 25 g of the salt and 225 g of clean water of 25 ° C to a 300 ml beaker, stirring the resulting aqueous slurry for 30 minutes and then measuring the pH. The above-mentioned n-value, the number-average degree of condensation, can be determined by 31P solid NMR. Out JR van Wazer, CF Callis, J. Shoolery and R. Jones, J. Am. Chem. Soc., 78, 5715, 1956 , it is known that the number of adjacent phosphate groups indicates a unique 'chemical shift' that allows a clear distinction between orthophosphates, pyrophosphates and polyphosphates. In EP1095030B1 is also a process for the preparation of the desired polyphosphate salt of a 1,3,5-triazine compound having an n value of 20 to 200 and their 1,3,5-triazine content 1.1 to 2.0 mol of a 1.3, 5-triazine compound is described. This process involves the conversion of a 1,3,5- Triazine compound with orthophosphoric acid in its orthophosphate salt, followed by dehydration and heat treatment to convert the orthophosphate salt into a polyphosphate of the 1,3,5-triazine compound. This heat treatment is preferably carried out at a temperature of at least 300 ° C, and preferably at least 310 ° C. In addition to orthophosphates of 1,3,5-triazine compounds, other 1,3,5-triazine phosphates may also be used, including, for example, a mixture of orthophosphates and pyrophosphates.

Suitable guanidine salts are CAS-No. G-carbonate 593-85-1 G-cyanurate prim. 70285-19-7 G-phosphate prim. 5423-22-3 G-phosphate sec. 5423-23-4 G-sulfate prim. 646-34-4 G-sulfate sec. 594-14-9 Pentaerythritborsäureguanidin N / A Neopentylglycolborsäureguanidin N / A and urea phosphate green 4861-19-2 urea cyanurate 57517-11-0 ammeline 645-92-1 ammelide 645-93-2 melem 1502-47-2 Melon 32518-77-7

Among compounds in the context of the present invention, both z. B. benzoguanamine itself and its adducts or salts as well as the nitrogen-substituted derivatives and its adducts or salts are understood.

oder dessen Umsetzungsprodukte mit aromatischen Carbonsäuren Ar(COOH)_m, welche gegebenenfalls in Mischung miteinander vorliegen können, wobei Ar ein ein-, zwei- oder dreikerniges aromatisches Sechsringsystem bedeutet und m 2, 3 oder 4 ist.Also suitable are ammonium polyphosphate (NH ₄ PO ₃ ) _n with n about 200 to 1000, preferably 600 to 800, and tris (hydroxyethyl) isocyanurate (THEIC) of the formula IV

or its reaction products with aromatic carboxylic acids Ar (COOH) _m , which may optionally be present in admixture with each other, wherein Ar is a mono-, di- or trinuclear aromatic six-membered system and m is 2, 3 or 4.

Suitable carboxylic acids are, for example, phthalic acid, isophthalic acid, terephthalic acid, 1,3,5-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, pyromellitic acid, mellophanic acid, prehnitic acid, 1-naphthoic acid, 2-naphthoic acid, naphthalenedicarboxylic acids and anthracene carboxylic acids.

The preparation is carried out by reacting the tris (hydroxyethyl) isocyanurate with the acids, their alkyl esters or their halides according to the processes of EP-A 584 567 ,

Such reaction products are a mixture of monomeric and oligomeric esters, which may also be crosslinked. The degree of oligomerization is usually from 2 to about 100, preferably from 2 to 20. Preference is given to mixtures of THEIC and / or its reaction products with phosphorus-containing Nitrogen compounds, in particular (NH ₄ PO ₃ ) _n or melamine pyrophosphate or polymeric melamine phosphate used. The mixing ratio z. B. from (NH ₄ PO ₃ ) _n to THEIC is preferably 90 to 50 to 10 to 50, in particular 80 to 50 to 50 to 20 wt .-%, based on the mixture of such components B1).

in der R, R' geradkettige oder verzweigte Alkylreste mit 1 bis 10 C-Atomen, bevorzugt Wasserstoff bedeutet und insbesondere deren Addukte mit Phosphorsäure, Borsäure und/oder Pyrophosphorsäure.Also suitable are benzoguanamine compounds of the formula V

in which R, R 'are straight-chain or branched alkyl radicals having 1 to 10 C atoms, preferably hydrogen, and in particular their adducts with phosphoric acid, boric acid and / or pyrophosphoric acid.

wobei R, R' die in Formel V angegebene Bedeutung haben sowie deren Salze mit Phosphorsäure, Borsäure und/oder Pyrophosphorsäure sowie Glycolurile der Formel VII oder dessen Salze mit den o. g. Säuren

in der R die in Formel V genannte Bedeutung hat.Also preferred are allantoin compounds of the formula VI

where R, R 'have the meaning given in formula V and their salts with phosphoric acid, boric acid and / or pyrophosphoric acid and glycolurils of the formula VII or its salts with the abovementioned acids

in which R has the meaning given in formula V.

Suitable products are commercially available or according to DE-A 196 14 424 available.

The usable according to the invention cyanoguanidine (Formula VIII) is obtained for. B. by reaction of calcium cyanamide (calcium cyanamide) with carbonic acid, wherein the resulting cyanamide dimerized at pH 9 to 10 to cyanoguanidine.

The commercially available product is a white powder having a melting point of 209 ° C to 211 ° C.

Suitable components (B3) are basic or amphoteric oxides, hydroxides, carbonates, silicates, borates, phosphates or stannates or mixtures of zinc, anhydrous zinc borate or zinc borate of the general formula 2Zn _0.3 B ₂ O ₃ xH ₂ O in which X is from 3.3 to 3.7, are preferred. This zinc borate is essentially stable even at the high processing temperatures of the polyamides and tends only slightly to cleave the water of hydration. Accordingly, zinc borates having a higher content of hydrated water are generally less suitable as synergists.

As component C), the molding compositions according to the invention contain 0.05 to 5, preferably 0.5 to 8.5 and in particular 1 to 2.5 wt .-% of an unmodified layered silicate. Unmodified in the sense of the invention means that there should be no size (surface treatment or organic modification with, for example, ammonium salts) and no delamination of the layers.

Phyllosilicates are naturally occurring minerals with layered polysilicate building units. The layer silicates include mineral groups such as mica, talc, serpentine, kaolinite and clay minerals such as vermiculite and muscovite. It is preferably serpentine Mg ₃ (OH) ₄ [Si ₂ O ₅ ] and kaolinite Al ₂ (OH) ₄ [Si ₂ O ₅ ] as a representative of the group of two-layer phyllosilicates. Particularly preferred is talc, which is a hydrated magnesium silicate of the composition Mg ₃ (OH) ₂ [Si ₂ O ₅ ] ₂ or 3MgO x 4SiO ₂ .H ₂ O. The so-called three-layer phyllosilicates have a triclinic, monoclinic or rhombic crystal structure with a platelet-like appearance. At further trace elements Mn, Ti, Cr, Ni, Na and K may be present, wherein the OH groups may be partially replaced by fluoride.

Very particular preference is given to using talc whose particle size is 99% <20 μm. The particle size distribution is usually determined by sedimentation analysis DIN 66, 16-1 determined and is preferably: d98% <12 microns, d50% <2.5 microns with the proviso that> 50% of all particles are <2.5 microns.

Such products are commercially available as Micro-Talc I.T. Extra (Mondo Minerals).

As component D), the molding compositions of the invention may contain up to 70, preferably up to 50 wt .-% of other additives, different from B) and C).

As fibrous or particulate fillers D1) are carbon fibers, glass fibers, glass beads, amorphous silica, calcium silicate, calcium metasilicate, magnesium carbonate, chalk, powdered quartz, barium sulfate and feldspar called in amounts of 1 to 50 wt .-%, in particular 5 to 40 , preferably 10 to 40 wt .-% are used.

Preferred fibrous fillers are carbon fibers, aramid fibers and potassium titanate fibers, glass fibers being particularly preferred as E glass. These can be used as rovings or cut glass in the commercial forms.

The fibrous fillers can be surface-pretreated for better compatibility with the thermoplastic with a silane compound.

n eine ganze Zahl von 2 bis 10, bevorzugt 3 bis 4
m eine ganze Zahl von 1 bis 5, bevorzugt 1 bis 2
k eine ganze Zahl von 1 bis 3, bevorzugt 1Suitable 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 meanings:

n is an integer from 2 to 10, preferably 3 to 4
m is an integer from 1 to 5, preferably 1 to 2
k is an integer from 1 to 3, preferably 1

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

The silane compounds are generally used in combination with other components such. As polyurethanes, isocyanates, polyols, polyester polyols, urea condensates or acrylate polymers such z. In US5804313 . EP0224122B1 and US4394414 described 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)) used for surface coating.

Also suitable are acicular mineral fillers.

For the purposes of the invention, needle-shaped mineral fillers are understood to mean a mineral filler with a pronounced needle-like character. An example is acicular wollastonite. Preferably, the mineral has an L / D (length diameter) ratio of 8: 1 to 35: 1, preferably 8: 1 to 11: 1. The mineral filler may optionally be pretreated with the silane compounds mentioned above; however, pretreatment is not essential.

As component D2), 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.

Preference is given to Al, alkali metal, alkaline earth metal salts or ester or amides of fatty acids having 10 to 44 carbon atoms, preferably having 12 to 44 carbon atoms.

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

Preferred metal salts are Ca-stearate and Ca-montanate as well as Al-stearate.

It is also possible to use mixtures of different salts, the mixing ratio being arbitrary.

The carboxylic acids can be 1- or 2-valent. Examples which may be mentioned are pelargonic acid, palmitic acid, lauric acid, margaric acid, dodecanedioic acid, behenic acid and particularly preferably stearic acid, capric acid and montanic acid (mixture of fatty acids having 30 to 40 carbon atoms).

The aliphatic alcohols can be 1 to 4 valent. Examples of alcohols are n-butanol, n-octanol, stearyl alcohol, ethylene glycol, propylene glycol, neopentyl glycol, pentaerythritol, with glycerol and pentaerythritol being preferred.

The aliphatic amines can be monohydric to trihydric. Examples of these are stearylamine, ethylenediamine, propylenediamine, hexamethylenediamine, di (6-aminohexyl) amine, with ethylenediamine and hexamethylenediamine being particularly preferred. Accordingly, preferred esters or amides are glycerin distearate, glycerol tristearate, ethylenediamine distearate, glycerin monopalmitate, glycerol trilaurate, glycerin monobehenate and pentaerythritol tetrastearate.

It is also possible to use mixtures of different esters or amides or esters with amides in combination, the mixing ratio being arbitrary.

As component D3), the molding compositions of the invention 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 Mixture with an alkali metal halide, preferably KJ, in particular in the ratio 1: 4., Or contain a sterically hindered phenol or mixtures thereof.

Suitable salts of monovalent copper are preferably copper (I) acetate, copper (I) chloride, bromide and iodide. By way of example, mention may also be made of complexes of copper iodide with triphenylphosphine. These are contained in amounts of 5 to 500 ppm of copper, preferably 10 to 250 ppm, based on polyamide.

The advantageous properties are obtained in particular when the copper is present in molecular distribution in the polyamide. This is achieved by adding to the molding compound a concentrate containing polyamide, a salt of monovalent copper and an alkali halide in the form of a solid, homogeneous solution. A typical concentrate is z. B. from 79 to 95 wt .-% polyamide and 21 to 5 wt .-% of a mixture of copper iodide or bromide and potassium iodide. The concentration of the solid homogeneous solution of copper 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.

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

Suitable hindered phenols D3) are in principle all compounds having a phenolic structure which have at least one sterically demanding group on the phenolic ring.

in Betracht, in der bedeuten:
R¹ und R² eine Alkylgruppe, eine substituierte Alkylgruppe oder eine substituierte Triazolgruppe, wobei die Reste R¹ und R² gleich oder verschieden sein können und R³ eine Alkylgruppe, eine substituierte Alkylgruppe, eine Alkoxigruppe oder eine substituierte Aminogruppe.Preferably z. B. Compounds of the formula

into consideration, in which mean:
R ¹ and R ^{2 are} an alkyl group, a substituted alkyl group or a substituted triazole group, wherein the radicals R ¹ and R ^{2 may be the} same or different and R ^{3 is} an alkyl group, a substituted alkyl group, an alkoxy group or a substituted amino group.

Antioxidants of the type mentioned are, for example, in the DE-A 27 02 661 ( US Pat. No. 4,360,617 ).

Another group of preferred sterically hindered phenols are derived from substituted benzenecarboxylic acids, especially substituted benzenepropionic acids.

wobei R⁴, R⁵, R⁷ und R⁸ unabhängig voneinander C₁-C₈-Alkylgruppen darstellen, die ihrerseits substituiert sein können (mindestens eine davon ist eine sterisch anspruchsvolle Gruppe) und R⁶ einen zweiwertigen aliphatischen Rest mit 1 bis 10 C-Atomen bedeutet, der in der Hauptkette auch C-O-Bindungen aufweisen kann.Particularly preferred compounds of this class are compounds of the formula

where R ⁴ , R ⁵ , R ⁷ and R ⁸ independently of one another are 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 is} a bivalent aliphatic radical having 1 to 10C Atom, which may also have CO bonds in the main chain.

(Irganox^® 245 der Firma BASF SE)

(Irganox^® 259 der Firma BASF SE)

(Irganox^® 1098 der Firma BASF SE) Preferred compounds corresponding to these forms are

(Irganox ^® 245 from BASF SE)

(Irganox ^® 259 from BASF SE)

(Irganox ^® 1098 from BASF SE)

By way of example, the following may be mentioned by way of example as sterically hindered phenols:
2,2'-methylenebis (4-methyl-6-tert-butylphenol), 1,6-hexanediol bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate ], Pentaerythritol 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-ylmethyl-3,5-di-tert-butyl-4-hydroxyhydrocinnamate, 3,5-di-tert-butyl-4-hydroxyphenyl 3,5-distearylthiotriazylamine, 2- (2'-hydroxy-3'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 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-hydroxybenzyldimethylamine.

Have been found to be particularly effective and therefore preferably be used 2,2'-methylenebis (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 Irganox ^® 245 from BASF SE, which is particularly well suited described above.

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

In some cases, sterically hindered phenols having no more than one sterically hindered group ortho to the phenolic hydroxy group have been found to be particularly advantageous; especially when assessing color stability when stored in diffused light for extended periods of time.

As component D4), the molding compositions of 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.

Nigrosines are generally understood to mean a group of black or gray indulene-related phenazine dyes (azine dyes) in various embodiments (water-soluble, fat-soluble, gas-soluble) used in wool dyeing and printing, in black dyeing of silks, for dyeing of leather, shoe creams, varnishes, plastics, stoving lacquers, inks and the like, as well as being used as microscopy dyes.

The nigrosine is technically obtained by heating nitrobenzene, aniline and aniline with anhydrous metal. Iron and FeCl ₃ (name of Latin niger = black).

Component D4) can be used as the free base or else as the salt (for example hydrochloride).

Further details on Nigrosinen are for example the electronic lexicon Römpp Online, Version 2.8, Thieme-Verlag Stuttgart, 2006, keyword "Nigrosine" refer to.

Other customary additives D) are, for example, in amounts of up to 25, preferably up to 20 wt .-% rubber-elastic polymers (often also referred to as impact modifiers, elastomers or rubbers).

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 having 1 to 18 C atoms in the alcohol component.

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

In the following some preferred types of such elastomers are presented.

Preferred types of such elastomers are the so-called ethylene-propylene (EPM) and ethylene-propylene-diene (EPDM) rubbers.

EPM rubbers generally have practically no double bonds, while EPDM rubbers can have 1 to 20 double bonds / 100 carbon atoms.

As diene monomers for EPDM rubbers, for example, conjugated dienes such as isoprene and butadiene, non-conjugated dienes having 5 to 25 carbon atoms such as penta-1,4-diene, hexa-1,4-diene, hexa-1,5 -diene, 2,5-dimethylhexa-1,5-diene and octa-1,4-diene, cyclic dienes such as cyclopentadiene, cyclohexadienes, cyclooctadienes and dicyclopentadiene and alkenylnorbornenes such as 5-ethylidene-2-norbornene, 5-butylidene-2 norbornene, 2-methallyl-5-norbornene, 2-isopropenyl-5-norbornene and tricyclodienes such as 3-methyltricyclo (5.2.1.0.2.6) -3,8-decadiene or mixtures thereof. Preference is given to hexa-1,5-diene, 5-ethylidenenorbornene and dicyclopentadiene. The diene content of the EPDM rubbers is preferably 0.5 to 50, in particular 1 to 8 wt .-%, based on the total weight of the rubber.

EPM or EPDM rubbers may preferably also be grafted with reactive carboxylic acids or their derivatives. Here are z. For example, acrylic acid, methacrylic acid and derivatives thereof, for. As glycidyl (meth) acrylate, and called maleic anhydride.

wobei R¹ bis R⁹ Wasserstoff oder Alkylgruppen mit 1 bis 6 C-Atomen darstellen und m eine ganze Zahl von 0 bis 20, g eine ganze Zahl von 0 bis 10 und p eine ganze Zahl von 0 bis 5 ist.Another group of preferred rubbers are copolymers of ethylene with acrylic acid and / or methacrylic acid and / or the esters of these acids. In addition, the rubbers may still dicarboxylic acids such as maleic acid and fumaric acid or derivatives of these acids, eg. As esters and anhydrides, and / or containing epoxy groups monomers. These dicarboxylic acid derivatives or monomers containing epoxy groups are preferably incorporated into the rubber by addition of monomers containing dicarboxylic acid or epoxy groups of the general formulas I or II or III or IV to the monomer mixture R ¹ C (COOR ² ) = C (COOR ³ ) R ⁴ (I)

wherein R ¹ to R ^{9 represent} hydrogen or alkyl groups having 1 to 6 carbon atoms and m is an integer of 0 to 20, g is an integer of 0 to 10 and p is an integer of 0 to 5.

The radicals R ¹ to R ⁹ preferably denote hydrogen, where m is 0 or 1 and g is 1. The corresponding compounds are maleic acid, fumaric acid, maleic anhydride, allyl glycidyl ether and vinyl glycidyl ether.

Preferred compounds of formulas I, II and IV are maleic acid, maleic anhydride and epoxy group-containing esters of acrylic acid and / or methacrylic acid, such as glycidyl acrylate, glycidyl methacrylate and the esters with tertiary alcohols, such as t-butyl acrylate. Although the latter have no free carboxyl groups, their behavior is close to the free acids and are therefore termed monomers with latent carboxyl groups.

Advantageously, the copolymers consist of 50 to 98 wt .-% of ethylene, 0.1 to 20 wt .-% of monomers containing epoxy groups and / or methacrylic acid and / or acid-anhydride-containing monomers and the remaining amount of (meth) acrylic acid esters.

Particularly preferred are copolymers of
50 to 98, in particular 55 to 95 wt .-% ethylene,
0.1 to 40, in particular 0.3 to 20 wt .-% glycidyl acrylate and / or glycidyl methacrylate, (meth) acrylic acid and / or maleic anhydride, and
1 to 45, in particular 5 to 40 wt .-% n-butyl acrylate and / or 2-ethylhexyl acrylate.

Further preferred esters of acrylic and / or methacrylic acid are the methyl, ethyl, propyl and i- or t-butyl esters.

In addition, vinyl esters and vinyl ethers can also be used as comonomers.

The ethylene copolymers described above can be prepared by methods known per se, preferably by random copolymerization under high pressure and elevated temperature. Corresponding methods are generally known.

Preferred elastomers are also emulsion polymers whose preparation z. As described in Blackley in the monograph "Emulsion Polymerization". The emulsifiers and catalysts which can be used are known per se.

Basically, homogeneously constructed elastomers or those with a shell structure can be used. The shell-like structure is determined by the order of addition of the individual monomers; the morphology of the polymers is also influenced by this order of addition.

Only representative may be here as monomers for the preparation of the rubber part of the elastomers acrylates such. For example, n-butyl acrylate and 2-ethylhexyl acrylate, corresponding methacrylates, butadiene and isoprene and their mixtures called. These monomers can with other monomers such. As styrene, acrylonitrile, vinyl ethers and other acrylates or methacrylates such as methyl methacrylate, methyl acrylate, ethyl acrylate and propyl acrylate are copolymerized.

The soft or rubber phase (with a glass transition temperature below 0 ° C) of the elastomers may be the core, the outer shell, or a middle shell (for elastomers having more than two shell construction); in the case of multi-shell elastomers, it is also possible for a plurality of shells to consist of a rubber phase.

If, in addition to the rubber phase, one or more hard components (having glass transition temperatures of more than 20 ° C.) are involved in the construction of the elastomer, these are generally prepared by polymerization of styrene, acrylonitrile, methacrylonitrile, α-methylstyrene, p-methylstyrene, acrylic esters and methacrylates such as methyl acrylate, ethyl acrylate and methyl methacrylate produced as main monomers. In addition, smaller proportions of other comonomers can also be used here.

eingeführt werden können,
wobei die Substituenten folgende Bedeutung haben können:
R¹⁰ Wasserstoff oder eine C₁- bis C₄-Alkylgruppe,
R¹¹ Wasserstoff, eine C₁- bis C₈-Alkylgruppe oder eine Arylgruppe, insbesondere Phenyl,
R¹² Wasserstoff, eine C₁- bis C₁₀-Alkyl-, eine C₆- bis C₁₂-Arylgruppe oder -OR¹³
R¹³ eine C₁- bis C₈-Alkyl- oder C₆- bis C₁₂-Arylgruppe, die gegebenenfalls mit O- oder N-haltigen Gruppen substituiert sein können,
X eine chemische Bindung, eine C₁- bis C₁₀-Alkylen- oder C₆-C₁₂-Arylengruppe oder

Y O-Z oder NH-Z und
Z eine C₁- bis C₁₀-Alkylen- oder C₆- bis C₁₂-Arylengruppe.In some cases it has proven to be advantageous to use emulsion polymers which have reactive groups on the surface. Such groups are for. For example, epoxy, carboxyl, latent carboxyl, amino or amide groups and functional groups by the concomitant use of monomers of the general formula

can be introduced
where the substituents may have the following meanings:
R ^{10 is} hydrogen or a C ₁ - to C ₄ -alkyl group,
R ^{11 is} hydrogen, a C ₁ - to C ₈ -alkyl group or an aryl group, in particular phenyl,
R ^{12 is} hydrogen, a C ₁ - to C ₁₀ -alkyl, a C ₆ - to C ₁₂ -aryl group or -OR ¹³
R ^{13 is} a C ₁ - to C ₈ -alkyl or C ₆ - to C ₁₂ -aryl group which may optionally be substituted by O- or N-containing groups,
X is a chemical bond, a C ₁ - to C ₁₀ -alkylene or C ₆ -C ₁₂ -arylene group or

Y OZ or NH-Z and
Z is a C ₁ - to C ₁₀ -alkylene or C ₆ - to C ₁₂ -arylene group.

Also in the EP-A 208 187 grafting monomers described are suitable for introducing reactive groups on the surface.

Other examples which may be mentioned are acrylamide, methacrylamide and substituted esters of acrylic acid or methacrylic acid, such as (Nt-butylamino) -ethyl methacrylate, (N, N-dimethylamino) ethyl acrylate, (N, N-dimethylamino) -methyl acrylate and (N, N-diethylamino) called ethyl acrylate.

Furthermore, the particles of the rubber phase can also be crosslinked. Examples of monomers acting as crosslinking agents are buta-1,3-diene, divinylbenzene, diallyl phthalate and dihydrodicyclopentadienyl acrylate and those described in US Pat EP-A 50 265 described compounds.

Furthermore, it is also possible to use so-called graft-linking monomers, ie monomers having two or more polymerizable double bonds which react at different rates during the polymerization. Preferably, those compounds are used in which at least one reactive group polymerized at about the same rate as the other monomers, while the other reactive group (or reactive groups) z. B. polymerized much slower (polymerize). The different polymerization rates bring a certain proportion unsaturated double bonds in the rubber with it. If a further phase is subsequently grafted onto such a rubber, the double bonds present in the rubber react at least partially with the grafting monomers to form chemical bonds, ie the grafted-on phase is at least partially linked to the grafting base via chemical bonds.

Examples of such graft-crosslinking monomers are allyl-containing monomers, in particular allyl esters of ethylenically unsaturated carboxylic acids such as allyl acrylate, allyl methacrylate, diallyl maleate, diallyl fumarate, diallyl itaconate or the corresponding monoallyl compounds of these dicarboxylic acids. In addition, there are a variety of other suitable graft-linking monomers; for more details, for example, on the U.S. Patent 4,148,846 directed.

In general, the proportion of these crosslinking monomers in the impact-modifying polymer is up to 5% by weight, preferably not more than 3% by weight, based on the impact-modifying polymer.

In the following, some preferred emulsion polymers are listed. First, graft polymers having a core and at least one outer shell, which have the following structure: Type Monomers for the core Monomers for the shell I Buta-1,3-diene, isoprene, n-butyl acrylate, ethylhexyl acrylate or mixtures thereof Styrene, acrylonitrile, methylmethacrylate II like I but with the co-use of crosslinkers like I III like I or II n-butyl acrylate, ethyl acrylate, methyl acrylate, buta-1,3-diene, isoprene, ethylhexyl acrylate IV like I or II as I or III but with the concomitant use of monomers having reactive groups as described herein V Styrene, acrylonitrile, methyl methacrylate or mixtures thereof first shell of monomers as described under I and II for the core second shell as described under I or IV for the shell

Instead of graft polymers with a multi-shell structure can also homogeneous, d. H. single-shell elastomers of buta-1,3-diene, isoprene and n-butyl acrylate or copolymers thereof are used. These products can also be prepared by concomitant use of crosslinking monomers or monomers having reactive groups.

Examples of preferred emulsion polymers are n-butyl acrylate / (meth) acrylic acid copolymers, n-butyl acrylate / glycidyl acrylate or n-butyl acrylate / glycidyl methacrylate copolymers, graft polymers having an inner core of n-butyl acrylate or butadiene-based and an outer shell of the above copolymers and copolymers of ethylene with comonomers which provide reactive groups.

The elastomers described can also be prepared by other conventional methods, for. B. by suspension polymerization.

Silicone rubbers, as in DE-A 37 25 576 , of the EP-A 235 690 , of the DE-A 38 00 603 and the EP-A 319 290 are also preferred.

Of course, it is also possible to use mixtures of the rubber types listed above.

As component D), the thermoplastic molding compositions of the invention may contain conventional processing aids such as stabilizers, antioxidants, agents against heat decomposition and decomposition by ultraviolet light, lubricants and mold release agents, colorants such as dyes and pigments, nucleating agents, plasticizers, etc.

Examples of antioxidants and heat stabilizers are sterically hindered phenols and / or phosphites and amines (eg TAD), hydroquinones, aromatic secondary amines such as diphenylamines, various substituted representatives of these groups and mixtures thereof in concentrations up to 1 wt .-%, based on the weight of the thermoplastic molding compositions called.

As UV stabilizers, which are generally used in amounts of up to 2 wt .-%, based on the molding composition, various substituted resorcinols, salicylates, benzotriazoles and benzophenones may be mentioned.

It is possible to add inorganic pigments such as titanium dioxide, ultramarine blue, iron oxide and carbon black, furthermore organic pigments such as phthalocyanines, quinacridones, perylenes and also dyes such as anthraquinones as colorants.

As nucleating agents, sodium phenylphosphinate, alumina, silica may be used.

The thermoplastic molding compositions according to the invention can be prepared by processes known per se, in which mixing the starting components in conventional mixing devices such as screw extruders, Brabender mills or Banbury mills and then extruded. After extrusion, the extrudate can be cooled and comminuted. It is also possible to premix individual components and then to add the remaining starting materials individually and / or likewise mixed. The mixing temperatures are usually 230 to 320 ° C.

According to a further preferred procedure, the components B) and C) and optionally D) can be mixed with a prepolymer, formulated and granulated. The resulting granules are then condensed in solid phase under inert gas continuously or discontinuously at a temperature below the melting point of component A) to the desired viscosity.

The thermoplastic molding compositions according to the invention are distinguished by good flame retardance and excellent glow-wire resistance as well as good sliding friction properties.

These are suitable for the production of fibers, films and moldings of any kind. Below are some examples: connectors, plugs, connector parts, wiring harness components, circuit carriers, circuit carrier components, three-dimensional injection-molded circuit strength, electrical connection elements and mechatronic components.

The moldings or semifinished products to be produced according to the invention from the thermoplastic molding compositions can be used, for example, in the motor vehicle, electrical, electronics, telecommunications, information technology, entertainment, computer industry, in vehicles and other means of transportation, in ships, spaceships, in the household, in office equipment, sports, in medicine as well as generally in objects and building parts which require increased fire protection.

For the kitchen and household sector, the use of flow-improved polyamides for the production of components for kitchen barley, such. As fryers, irons, buttons, and applications in the garden and leisure area possible.

Examples

The following components were used:

Component A

• Polyamide 66 with a viscosity number VZ of 150 ml / g, measured as 0.5 wt .-% solution in 96 wt .-% sulfuric acid at 25 ° C after ISO 307 , (It was used Ultramid ^® A27 from BASF SE).

Component B

• B / 1 Aluminum diethyl phosphinate (Exolit OP1230 ^® ex Fa. Clariant), B / 2 Melamine polyphosphate (Melapur ^® 200/70 ex BASF SE), B / 3 zinc borate (Fire Brake 500 ex Rio Tinto)

Component C

• Talc (Finntalc ex Mondo Minerals) d ₉₈ <12 μm, d ₅₀ <2.5 μm

Component D / 1

• Standard chopped glass fiber for polyamides, length = 4.5 mm, diameter = 10 μm.

Component D / 2

• Stabilizer based on sterically hindered phenols
• Irganox ^® 1098 from BASF SE,

Component D / 3

• Processing Aid Al Stearate

Production of molding compounds

For proof of the inventions described improvements for glow wire resistance corresponding plastic molding compounds were prepared by compounding. The individual components were mixed for this purpose in a twin-screw extruder ZSK 26 (Berstorff) at a throughput of 20 kg / h and about 270 ° C at a flat temperature profile, discharged as a strand, cooled to Granulierfähigkeit and granulated.

The specimens for the tests listed in Table 1 were sprayed on an Arburg 420C injection molding machine at a melt temperature of about 270 ° C. and a mold temperature of about 80 ° C.

measurement methods

The flame retardancy of the molding compositions was firstly determined by the method UL94V (Underwriters Laboratories)
Inc. Standard of Safety, "Test for Flammability of Plastic Materials for Parts in Devices and Appliances", p. 14 to p. 18 Northbrook 1998) certainly.

Glow wire resistance was detected by glow wire ignition test GWIT (Glow Wire Ignition Temperature) DIN EN 60695-2-13 certainly. In the GWIT test, the maximum temperature is determined on 3 test specimens (for example on 60 × 60 × 1.5 mm geometry plates) with the aid of a glowing wire at temperatures between 550 and 960 ° C., and in 3 consecutive tests during the exposure time of the filament does not lead to ignition. The specified filament ignition temperature is 25 K above the maximum determined temperature. The criterion of ignition is a flame with firing times> 5 sec.

The wear protection was determined by means of a pin-disc test ( DIN ISO 7148-2 (2001-03) / Testing of plain bearing materials made of plastic, test method A Pin / washer ). The abrasion ratio indicates the wear in μm / km running distance. Smaller values mean less wear behavior.

The compositions of the molding compositions and the results of the measurements are shown in the table Component [% by weight] Comparative example Inventive Example 1 Inventive Example 2 A 54.3 54.3 53.3 B / 1 12.8 11.5 12.2 B / 2 6.4 5.8 6.1 B / 3 0.8 0.7 0.7 D / 1 25 25 25 C 0 2 2 D / 2 + D / 3 0.7 * 0.7 * 0.7 * UL94 (0.8mm / 1.6mm) V-0 / nb V-0 / V-0 V-0 / V-0 GWIT 775 ° C / 1.5 mm not fulfilled Fulfills Fulfills GWIT max./1.5 mm [° C] <750 825 850 Wear ratio in the pin-disk test / [μm / km] 1.7 nb 1.3 * 0.5% IRGANOX 1098 (commercial product BASF) + 0.2% aluminum stearate

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 19933901 A [0003]
• EP 1762592 A [0005]
• US 2071250 [0012]
• US 2071251 [0012]
• US 2130523 [0012]
• US 2130948 [0012]
• US 2241322 [0012]
• US 2312966 [0012]
• US 2512606 [0012]
• US 3393210 [0012]
• DE 10313681 A [0017]
• EP 1198491 A [0017]
• EP 922065 [0017]
• EP 38094 A [0018]
• EP 38582A [0018]
• EP 39524A [0018]
• EP 299444A [0020]
• EP 1994075 A [0020]
• EP 129195A [0021]
• EP 129196A [0021]
• EP 1095030 B1 [0031, 0031]
• EP 584567A [0036]
• DE 19614424 A [0040]
• US 5804313 [0054]
• EP 0224122 B1 [0054]
• US 4394414 [0054]
• DE 2702661 A [0072]
• US 4360617 A [0072]
• EP 208187 A [0107]
• EP 50265A [0109]
• US 4148846 [0111]
• DE 3725576A [0117]
• EP 235690A [0117]
• DE 3800603 A [0117]
• EP 319290A [0117]

Cited non-patent literature

• IEC 60695-2-13 [0003]
• ISO 307 [0011]
• JR van Wazer, CF Callis, J. Shoolery and R. Jones, J. Am. Chem. Soc., 78, 5715, 1956 [0031]
• DIN 66, 16-1 [0046]
• Römpp Online, Version 2.8, Thieme-Verlag Stuttgart, 2006, keyword "Nigrosine" [0084]
• Houben-Weyl, Methods of Organic Chemistry, Vol. 14/1 (Georg Thieme Verlag, Stuttgart, 1961). Pages 392 to 406 [0087]
• CB Bucknall, "Toughened Plastics" (Applied Science Publishers, London, 1977) [0087]
• ISO 307 [0130]
• Inc. Standard of Safety, "Test for Flammability of Plastic Materials for Parts in Devices and Appliances", p. 14 to p. 18 Northbrook 1998) [0133]
• DIN EN 60695-2-13 [0134]
• DIN ISO 7148-2 (2001-03) / Testing of plain bearing materials made of plastic, test method A Pin / disk [0135]

Claims (8)

Thermoplastic molding compositions containing A) 10 to 99.5 wt .-% of a polyamide B) 0.45 to 25 wt .-% of a flame retardant combination of at least one phosphinic acid salt (B1), a nitrogen-containing flame retardant (B2) and optionally a zinc salt (83) C) 0.05 to 5 wt .-% of an unmodified layered silicate D) 0 to 70% by weight of further additives, where the sum of the weight percent of components A) to D) is 100%. Thermoplastic molding compositions according to claim 1, containing as flame retardant combination B) B1) 30 to 90% by weight B2) 10 to 50% by weight B3) 0 to 10% by weight Thermoplastic molding compositions according to claims 1 or 2, in which component C) is composed of talc. Thermoplastic molding compositions according to claims 1 to 3, in which component C) has a d ₉₈ value <12 μm. Thermoplastic molding compositions according to claims 1 to 4, in which component B3) consists of an inorganic zinc salt selected from the group of basic or amphoteric oxides, hydroxides, carbonates, silicates, borates, phosphates, stannates or mixtures thereof. Thermoplastic molding compositions according to claims 1 to 5, in which the component B1) is composed of phosphinic acid salts of the formula (I) and / or di-phosphinic acid salts of the formula (II) or their polymers

wherein R ¹ , R ^{2 are the} same or different and C ₁ -C ₆ alkyl, linear or branched and / or aryl; R ^{3 is} C ₁ -C ₁₀ -alkylene, linear or branched, C ₆ -C ₁₀ -arylene, -alkylarylene or -arylalkylene; M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K and / or a protonated nitrogen base; m 1 to 4; n 1 to 4; x is 1 to 4. Use of the thermoplastic molding compositions according to claims 1 to 6 for the production of glow wire resistant moldings of any kind. Glow wire resistant moldings of any kind, obtainable from the thermoplastic molding compositions according to claims 1 to 6.