FLAME-RETARDANT AND COLOR-STABLE POLYAMIDE MOLDING COMPOUNDS

Abstract

The invention relates to a flame-retardant polyamide composition containing: as component A) 1 to 96 wt. % of one or more thermoplastic polyamides; as component B) 2 to 25 wt. % of a diorganylphosphinic acid salt of formula (I),

##STR00001## wherein R.sup.1 and R.sup.2 are the same or different and C.sub.1-C.sub.18 alkyl is linear, branched or cyclical, C.sub.6-C.sub.18 aryl, C.sub.7-C.sub.18 arylalkyl and/or C.sub.7-C.sub.18 alkylaryl; 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 is 1 to 4; n is 1 to 4; as component C) 2 to 20 wt. % of at least a further polymer component, selected from the classes of thermoplastic polyester and polyester elastomers; as component D) 0 to 20 wt. % of a salt of the phosphorous acid of general formula (II),

[HP(O)O.sub.2].sup.2M.sup.m+(II) in which M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na and/or K; as component E) 0 to 20 wt. % of one or more condensation products of melamine and/or reaction products of melamine with phosphoric acids and/or melamine cyanurate; as component F) 0 to 50 wt. % of a filler and/or reinforcing agent; as component G) 0 to 5 wt. % of a compatibilizing agent for the polymer components; as component H) 0 to 2 wt. % of a phosphite or phosphonite or mixtures thereof; and as component I) 0 to 2 wt. % of an ester or salt of long-chained aliphatic carboxylic acids (fatty acids) which typically have chain lengths of C.sub.14 to C.sub.40, wherein the sum of the components always amounts to 100 wt. %.

Claims

1. A flame-retardant polyamide composition, comprising: as component A) 1% to 96% by weight of one or more thermoplastic polyamides; as component B) 2% to 25% by weight of a dialkylphosphinic salt of the formula (I) ##STR00006## in which R.sup.1 and R.sup.2 are the same or different and are C.sub.1-C.sub.18 alkyl in linear, branched or cyclic form, C.sub.6-C.sub.18 aryl, C.sub.7-C.sub.18 arylalkyl, and/or C.sub.7-C.sub.18 alkylaryl, 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 is 1 to 4, n is 1 to 4, as component C) 2-20% by weight of at least one further polymer component selected from the thermoplastic polyester and polyester elastomer classes, as component D) 0 to 20% by weight of a salt of phosphorous acid of the formula (II)
[HP(O)O.sub.2].sup.2M m.sup.+(II) in which M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and/or K; as component E) 0% to 20% by weight of one or more condensation products of melamine and/or reaction products of melamine with phosphoric acids and/or melamine cyanurate; as component F) 0% to 50% by weight of filler and/or reinforcer, as component G) 0-5% of a compatibilizer for the polymer components; as component H) 0% to 2% by weight of phosphite or phosphonite or mixtures thereof, and as component I) 0% to 2% by weight of an ester or salt of long-chain aliphatic carboxylic acids (fatty acids) typically having chain lengths of C.sub.14 to C.sub.40, wherein the sum total of the components is always 100% by weight.

2. The flame-retardant polyamide composition as claimed in claim 1, wherein polyam ides are nylon-6 or nylon-66 or mixtures of nylon-6 with nylon-66, and/or polyphthalamide.

3. The flame-retardant polyamide composition as claimed in claim 1, wherein R.sup.1, R.sup.2 in formula (I) are the same or different and are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, hexyl, and/or phenyl.

4. The flame-retardant polyamide composition as claimed in claim 1, wherein the thermoplastic polyesters and polyester elastomers are polyalkylene terephthalates.

5. The flame-retardant polyamide composition as claimed in claim 4, wherein the polyalkylene terephthalates are polyethylene terephthalate, polybutylene terephthalate, and/or copolyester elastomers.

6. The flame-retardant polyamide composition as claimed in claim 1, wherein component D) comprises reaction products of phosphorous acid with aluminum compounds.

7. The flame-retardant polyamide composition as claimed in claim 1, wherein component D) comprises aluminum phosphite [Al(H.sub.2PO.sub.3).sub.3], secondary aluminum phosphite [Al.sub.2(HPO.sub.3).sub.3], basic aluminum phosphite [Al(OH)(H.sub.2PO.sub.3).sub.2*2aq], aluminum phosphite tetrahydrate [Al.sub.2(HPO.sub.3).sub.3*4aq], aluminum phosphonate, Al.sub.7(HPO.sub.3).sub.9(OH).sub.6(1,6-hexanediamine).sub.1 512H.sub.20, Al.sub.2(HPO.sub.3).sup.3*xAl.sub.2O.sub.3*nH.sub.2O where x=1-2.27 and n=1-50, and/or Al.sub.4H.sub.6P.sub.16O.sub.18, or aluminum phosphites of the formulas (III), (IV), and/or (V), where formula (III) comprises: Al.sub.2(HPO.sub.3).sub.3 x(H.sub.2O).sub.q and q is 0 to 4; formula (IV) comprises: Al.sub.2.00M.sub.z(HPO.sub.3).sub.y(OH).sub.v x(H.sub.2O).sub.w and M represents alkali metal ions, z is 0.01 to 1.5, y is 2.63 to 3.5, v is 0 to 2, and w is 0 to 4; formula (V) comprises: Al.sub.2.00(HPO.sub.3).sub.u(H.sub.2PO.sub.3).sub.t x(H.sub.2O).sub.s and u is 2 to 2.99, t is 2 to 0.01, and s is 0 to 4, or the aluminum phosphite comprises mixtures of aluminum phosphite of the formula (III) with sparingly soluble aluminum salts and nitrogen-free extraneous ions, mixtures of aluminum phosphite of the formula (IV) with aluminum salts, mixtures of aluminum phosphites of the formulas (III) to (V) with aluminum phosphite [Al(H.sub.2PO.sub.3).sub.3], with secondary aluminum phosphite [Al.sub.2(HPO.sub.3).sub.3],with basic aluminum phosphite [Al(OH)(H.sub.2PO.sub.3).sub.2*2aq], with aluminum phosphite tetrahydrate [Al.sub.2(HPO.sub.3).sub.3*4aq], with aluminum phosphonate, with Al.sub.7(HPO.sub.3).sub.9(OH).sub.6(1,6-hexanediamine).sub.1.5*12H.sub.2O, with Al.sub.2(HPO.sub.3).sub.3*xAl.sub.2O.sub.3*nH.sub.2O where x=1-2.27 and n=1-50, and/or with Al.sub.4H.sub.6P16O.sub.18.

8. The flame-retardant polyamide composition as claimed in claim 1, wherein component E) comprises condensation products of melamine and/or reaction products of melamine with polyphosphoric acid and/or reaction products of condensation products of melamine with polyphosphoric acid or mixtures thereof; melem, melam, melon, dimelamine pyrophosphate, melamine polyphosphate, melem polyphosphate, melam polyphosphate, melon polyphosphate, and/or mixed polysalts thereof; nitrogen-containing phosphates of the formulas (NH.sub.4).sub.yH.sub.3-yPO.sub.4 or (NH.sub.4PO.sub.3).sub.z, where y is 1 to 3 and z is 1 to 10 000.

9. The flame-retardant polyamide composition as claimed in claim 1, wherein component E) comprises glass fibers, glass beads, and/or mineral fillers.

10. The flame-retardant polyamide composition as claimed in claim 1, wherein component G) is phthalic anhydride, pyromellitic anhydride, trimellitic anhydride, polyolefins grafted with maleic anhydride; epoxy compounds, epoxy-functional acrylates, bisoxazolines, carbodiim ides, diisocyanates, and/or diurethanes.

11. The flame-retardant polyamide composition as claimed in claim 1, wherein component H is phosphonites having a general structure:
R[P(OR.sup.5).sub.2]m (VI) where R is a mono- or polyvalent aliphatic, aromatic or heteroaromatic organic radical, and R.sup.5 is a compound of the structure (VII): ##STR00007## or the two R.sup.5 radicals form a bridging group of the structure (VIII): ##STR00008## where A is a direct bond, O, S, C.sub.1-18 alkylene (linear or branched), C.sub.1-18 alkylidene (linear or branched), in which R.sup.6 is independently C.sub.1-12 alkyl (linear or branched), C.sub.1-12 alkoxy, and/or C.sub.5-12 cycloalkyl, N is 0 to 5, and M is 1 to 4.

12. The flame-retardant polyamide composition as claimed in claim 1, wherein component I) comprises alkali metal, alkaline earth metal, aluminum, and/or zinc salts of long-chain fatty acids having 14 to 40 carbon atoms and/or reaction products of long-chain fatty acids having 14 to 40 carbon atoms with polyhydric alcohols such as ethylene glycol, glycerol, trimethylolpropane, and/or pentaerythritol.

13. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition comprises: 30% to 79.9% by weight of component A), 5% to 20% by weight of component B), 5% to 20% by weight of component C), 0% to 20% by weight of component D), 0% to 20% by weight of component E), 10% to 40% by weight of component F), 0% to 20% by weight of component G), 0% to 2% by weight of component H), and 0.1% to 2% by weight of component I).

14. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition comprises: 30% to 74.6% by weight of component A), 5% to 20% by weight of component B), 5% to 20% by weight of component C), 0% to 20% by weight of component D), 0% to 20% by weight of component E), 15% to 35% by weight of component F), 0.3% to 10% by weight of component G), 0% to 2% by weight of component H), and 0.1% to 2% by weight of component I).

15. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition comprises: 30% to 71.6% by weight of component A), 5% to 20% by weight of component B), 5% to 20% by weight of component C), 3% to 10% by weight of component D), 0% to 20% by weight of component E), 15% to 35% by weight of component F), 0.3% to 10% by weight of component G), 0% to 2% by weight of component H), and 0.1% to 2% by weight of component I).

16. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition comprises: 30% to 71.6% by weight of component A), 5% to 20% by weight of component B), 5% to 20% by weight of component C), 0% to 10% by weight of component D), 3% to 10% by weight of component E), 15% to 35% by weight of component F), 0.3% to 10% by weight of component G), 0% to 2% by weight of component H), and 0.1 A to 2% by weight of component I).

17. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition comprises: 30% to 71.4% by weight of component A), 5% to 20% by weight of component B), 5% to 20% by weight of component C), 0.1 A to 10% by weight of component D), 3% to 10% by weight of component E), 15% to 35% by weight of component F), 0.3% to 10% by weight of component G), 0.1% to 2% by weight of component H), and 0.1% to 2% by weight of component I).

18. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition further comprises telomers and that the telomers comprise ethylbutylphosphinic acid, dibutylphosphinic acid, ethylhexylphosphinic acid, butylhexylphosphinic acid, ethyloctylphosphinic acid, sec-butylethylphosphinic acid, (1-ethylbutyl)butylphosphinic acid, ethyl(1-methylpentyl)phosphinic acid, di-sec-butylphosphinic acid (di-1-methylpropylphosphinic acid), propyl(hexyl)phosphinic acid, dihexylphosphinic acid, hexyl(nonyl)phosphinic acid, dinonylphosphinic acid, and/or salts thereof with the metals Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and the telomers are different from component A).

19. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition additionally comprises zinc oxide, zinc borate, and/or zinc stannate.

20. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition comprises further additives, wherein the further additives are selected from the group consisting of antioxidants, UV stabilizers, gamma-ray stabilizers, hydrolysis stabilizers, co-stabilizers for antioxidants, antistats, emulsifiers, nucleating agents, plasticizers, processing auxiliaries, impact modifiers, dyes, pigments, and/or further flame retardants other than components B), D), E), F), H), and I).

21. The flame-retardant polyamide composition as claimed in claim 1, wherein the composition comprises, as a further component, iron in the form of an iron-containing substance, wherein the amount of iron-containing substance is 0.0001% to 10% by weight of the total mixture.

22. The use of a flame-retardant polyamide composition as claimed in claim 1 in the electricals and electronics sector, in or for plug connectors, current-bearing components in power distributors (residual current protection), circuit boards, potting compounds, power connectors, circuit breakers, lamp housings (LED housings), capacitor housings, coil elements, and ventilators for grounding contacts, plugs, in/on printed circuit boards, housings for plugs, cables, flexible circuit boards, charging cables for mobile phones, motor covers, textile coatings, and other products.

23. The use as claimed in claim 22, wherein the polyamides are in the form of shaped bodies, films, filaments, foils, and/or fibers.

24. A three-dimensional article comprising the flame-retardant polyamide composition as claimed in claim 1, wherein said article is a shaped body, injection molding, extrusion compound, and/or extrudate.

Description

EXAMPLES

[0192] 1. Components used

[0193] Commercial polymers (pellets):

[0194] Polyamides (component A):

[0195] Nylon-6,6 (PA 6,6-GR): Ultramid A27 (from BASF AG, Germany)

[0196] Further polymers (component C):

[0197] Polyester elastomer (TPE-E): Hytrel 4056 (from DuPont, USA)

[0198] Polyethylene terephthalate: Polyclear 1101 (from Invista, Germany)

[0199] Polybutylene terephthalate: Ultradur B4500 (from BASF, Germany)

[0200] Polystyrene: Styrolution PS 454 N natural (from Ineos, Germany)

[0201] ABS: Novodur P2-H (from Styrolution, Germany)

[0202] Polyglycol: Polyglycol 8000 P (from Clariant, Germany)

[0203] Polycarbonate: Makrolon 3208 (from Covestro, Germany)

[0204] Polycaprolactone: PC Resin 2-2 (from Changxing, China)

[0205] Component F: PPG HP 3610 EC 10 4.5 mm glass fibers (from PPG Ind. Fiber Glass, the Netherlands)

[0206] Flame retardant (component B):

[0207] Aluminum salt of diethylphosphinic acid, referred to hereinafter as Depal

[0208] Further flame retardants:

[0209] Component D: Aluminum salt of phosphorous acid, referred to hereinafter as Phopal

[0210] Component E: Melamine polyphosphate (Melapur 200/70, (from BASF, Germany), referred to as MPP

[0211] Compatibilizer (component G):

[0212] Zemac E60, polyethylene with maleic anhydride (Vertellus, USA)

[0213] Nexamitee 56 (Nexam Chemicals, Sweden)

[0214] Nexamite A99 (Nexam Chemicals, Sweden)

[0215] Licocene PE MA 4351 (Clariant, Germany)

[0216] Lotader AX 8700 (Arkema, France)

[0217] Trimellitic anhydride

[0218] Phosphonites (component H): Sandostab P-EPQ, from Clariant GmbH, Germany Wax components (component F)):

[0219] Licowax E, from Clariant Produkte (Deutschland) GmbH, Germany (esters of montan wax acid), component I)

[0220] 2. Production, processing, and testing of flame-retardant polymer molding compounds

[0221] The flame retardant components were mixed with the phosphonite, lubricants, and stabilizers in the ratio specified in the table and incorporated via the side intake of a twin-screw extruder (Leistritz ZSE 27/44D) into PA 6,6 at temperatures of 260 to 310 C. , and into PPA at 300-340 C. The glass fibers were added via a second side intake. The homogenized polymer strand was drawn off, cooled in a water bath, and then pelletized.

[0222] After sufficient drying, the molding compounds were processed into test specimens on an injection-molding machine (Arburg 320 C Allrounder) at melt temperatures of 250 to 340 C. , and tested and classified for flame retardancy using the UL 94 test (Underwriter Laboratories).

[0223] The UL 94 fire classifications are as follows: [0224] V-0: Afterflame time never longer than 10 sec, total of afterflame times for 10 flame applications not more than 50 sec, no flaming drops, no complete consumption of the specimen, afterglow time for specimens never longer than 30 sec after end of flame application. [0225] V-1: Afterflame time never longer than 30 sec after end of flame application, total of afterflame times for 10 flame applications not more than 250 sec, afterglow time for specimens never longer than 60 sec after end of flame application, remaining criteria as for V-0. [0226] V-2 Cotton indicator ignited by flaming drops, remaining criteria as for V-1

[0227] Not classifiable (ncl): Does not conform to fire classification V-2.

[0228] The flowability of the molding compounds was determined by establishing the melt volume flow rate (MVR) at 275 C./2.16 kg. A sharp rise in the MVR value indicates polymer degradation. Fillers also have an influence on the MVR.

[0229] Tensile strength (N/mm.sup.2), elongation at break, and tear strength were measured according to DIN EN ISO 527 (%); impact resistance [kJ/m.sup.2], and notched impact strength [kJ/m.sup.2] were measured according to DIN EN ISO 179.

[0230] The change in color after water storage was determined by storing 1 and 3 mm thick plates semi-immersed in water for seven days. The color (Lab values) was then measured in accordance with DIN 6174 using a CM 3600d spectrophotometer with white and black standards and measuring apertures, and the results were evaluated using SpectraMagic NX software (from Minolta Europe GmbH, Germany).

[0231] For comparability, all tests in the respective series, unless stated otherwise, were performed under identical conditions (temperature programs, screw geometry, injection molding parameters, etc.).

[0232] All amounts are reported as % by weight and are based on the polymer molding compound including the flame retardant combination and additives.

[0233] Table 1 shows polyamide molding compounds that contain component A) and component B) as a flame retardant mixture. These show clearly measurable corrosion. All amounts are reported as % by weight and are based on the polymer molding compound including the flame retardant combination and additives.

TABLE-US-00001 TABLE 1 PA 66 GF30 V-0 with phosphinates. C1 and C2 are comparative examples without addition of PET; I1 and I2 are inventive examples Example C1 I1 C2 I2 Nylon 66 47.6 37.6 47.6 37.6 Glass fibers 30 30 30 30 Depal 13.3 13.3 16.4 16.4 MPP 6.7 6.7 Zinc borate 1 1 Phopal 3.6 3.6 Polyethylene terephthalate 10 10 Carbon black masterbatch 30% in PA 6 2 2 2 2 Licowax E 0.3 0.3 0.3 0.3 PEP-Q 0.1 0.1 0.1 0.1 Color before storage in water black black black black L value 26.9 26.5 25.7 26.4 Color after storage in water gray black gray black L value 33.3 27.2 34.2 27.2 Delta Eab (D65) after 7 days in water 6.3 0.2 8.5 0.8 UL 94 0.4 mm V-0 V-0 V-0 V-0 UL 94 0.8 mm V-0 V-0 V-0 V-0 UL 94 1.6 mm V-0 V-0 V-0 V-0 E modulus/N/mm.sup.2 10901.55 11280.25 10858.91 11358.64 Tensile strength/N/mm.sup.2 143.02 133.72 144.11 138.33 Elongation at break/% 2.53 2.16 3.09 2.21

[0234] Comparative examples C.sub.1 and C.sub.2 show that flame-retardant polyamide 66 GF30 compounds undergo a change in color after storage in water for seven days at room temperature. This is observed both when using Depal together with melamine polyphosphate and when using Depal with Phopal. Examples I1 and I2 show that the addition of 10% polyethylene terephthalate almost completely eliminates the change in color after storage in water. At the same time, the UL 94 V-0 fire classification is maintained and the mechanical values are at a high level. Shaped bodies according to the invention have high surface quality, are easy to process, and are resistant to thermal aging.

[0235] Example 3 shows that addition of PET achieves good color stability, even when using a compatibilizer. This also improves the phase compatibility of PA 66 and PET, which leads to higher mechanical values.

TABLE-US-00002 TABLE 2 PA66/PET GF 30 V-0 with and without compatibilizer Example C3 I3 Nylon 66 56 44 Depal 12 12 ZeMac E60-P EMA copolymer 2 Glass fibers 30 30 Carbon black masterbatch (30% carbon 2 2 black in PA 6) Polyethylene terephthalate 10 dEab (D65) 7 days in water 3.39 0.21

TABLE-US-00003 TABLE 3 PA66/PET GF 30 V-0, I4-6: Variation of the PET content, C4 with polystyrene instead of PET Example C4 I4 I5 I6 PA 66 46 52 50 46 Depal 12 12 12 12 Glass fibers 30 30 30 30 Carbon black masterbatch (30% in PA 6) 2 2 2 2 PET 4 6 10 PS 10 dE*ab (D65) 7 days in water 3.65 0.16 0.16 0.15

[0236] Examples I4 and I5 show that addition of even a relatively small amount of PET results in there being no change in color after storage in water. Example 7 shows that addition of PBT and of a polyester elastomer likewise results in less change in color after storage in water. On the other hand, comparative examples C.sub.4 and C.sub.5 show that the addition of polystyrene or polyethylene glycol has no influence on the change in color after storage in water.

TABLE-US-00004 TABLE 4 Addition of polyglycol, polyester elastomer, and PBT Example C5 I7 I8 C6 PA 66 56 46 46 46 Depal 12 12 12 12 Glass fibers 30 30 30 30 Carbon black masterbatch (30% in PA 6) 2 2 2 2 Polyglycol 10 PBT 10 Polyester elastomer 10 dE*ab (D65) 4.15 0.32 0.15 4.81

TABLE-US-00005 TABLE 5 Addition of PC, ABS, SEBS, and polycaprolactone Example C7 C8 C9 C10 I9 PA 66 46 46 46 46 46 Depal 12 12 12 12 12 Glass fibers 30 30 30 30 30 Carbon black masterbatch 2 2 2 2 2 (30% in PA 6) ABS Novodur P2H-AT 10 PC Makrolon 3208 10 Polycaprolactone 10 Lotader AX 8700 5 SEBS Kraton FG 1901 GT 10 PET Polyclear 3300 5 dE*ab (D65) 3.25 1.28 1.6 1.92 0.18 Surface quality good moderate moderate good good

[0237] Example I9 shows that no change in color is observed after storage in water even when PET and a compatibilizer (Lotader) are added. With the addition of the other polymers, on the other hand, a discoloration after storage in water is observed as well as a deterioration in surface quality, recognizable by glass fibers at the surfaces (cloudy surfaces).