Flame-Retardant Polyamide Composition

Abstract

The invention relates to a flame-retardant polyamide composition, containing as component A 1 to 96% by weight of one or more thermoplastic polyamides, as component B 2 to 25% by weight of dialkylphosphinic salt of the formula (I) and/or a diphosphinic salt of the formula (II) and/or the polymers thereof, wherein R1, R2 are the same or different C1-C6 alkyl, linear or branched or H: R3 C1-C10 alkylene, linear or branched, C6-C10 arylene, C7-C20 alkylarylene or C7-C20 arylalkylene; M Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K and/or a protonized nitrogen base; m is 1 to 4; n is 1 to 4; x is 1 to 4, as component C 1 to 20% by weight salt of the phosphorous acid, as component D 1 to 50% by weight of filler or reinforcing material, as component E 0 to 2% by weight of a carboxyl ester amide, as component F 0 to 1% of a phosphonite or a mixture of a phosphonite and a phosphate, and as component G 0 to 1% by weight of an ester or salt of long-chain aliphatic carboxylic acids (fatty acids), which typically have chain lengths of C14 to C40, wherein the sum of the components is always 100% by weight.

Claims

1. A flame-retardant polyamide composition comprising as component A from 1 to 96% by weight of one or more thermoplastic polyamides, as component B from 2 to 25% by weight of a dialkylphosphinic salt of the formula (I) and/or of a diphosphinic salt of the formula (II) and/or polymers thereof, ##STR00006## in which R.sup.1 and R.sup.2 are identical or different and are C.sub.1-C.sub.6-alkyl, linear or branched or H; R.sup.3 is C.sub.1-C.sub.10-alkylene, linear or branched, C.sub.6-C.sub.10-arylene, C.sub.7-C.sub.20-alkylarylene, or C.sub.7-C.sub.20-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 is from 1 to 4; n is from 1 to 4; x is from 1 to 4, as component C from 1 to 20% by weight of a salt of phosphorous acid, as component D from 1 to 50% by weight of filler or reinforcing material, as component E from 0 to 2% by weight of a carboxylic ester amide, as component F from 0 to 1% by weight of a phosphonite or of a mixture of a phosphonite and a phosphite, and as component G from 0 to 1% by weight of an ester or salt of long-chain aliphatic carboxylic acids (fatty acids) having chain lengths of from C.sub.14 to C.sub.40, where the entirety of the components is always 100% by weight.

2. (canceled)

3. The flame-retardant polyamide composition as claimed in claim 1, comprising from 16 to 91.8% by weight of component A, from 5 to 20% by weight of component B, from 2 to 10% by weight of component C, from 1 to 50% by weight of component D, from 0 to 2% by weight of component E, from 0.1 to 1% by weight of component F, and from 0.1 to 1% by weight of component G.

4. The flame-retardant polyamide composition as claimed in claim 1, comprising from 16 to 82.7% by weight of component A, from 5 to 20% by weight of component B, from 2 to 10% by weight of component C, from 10 to 50% by weight of component D, from 0.1 to 2% by weight of component E, from 0.1 to 1% by weight of component F, and from 0.1 to 1% by weight of component G.

5. The flame-retardant polyamide composition as claimed in claim 1, comprising from 26 to 72.7% by weight of component A, from 5 to 20% by weight of component B, from 2 to 10% by weight of component C, from 20 to 40% by weight of component D, from 0.1 to 2% by weight of component E, from 0.1 to 1% by weight of component F, and from 0.1 to 1% by weight of component G.

6. The flame-retardant polyamide composition as claimed in claim 1, wherein the Comparative Tracking Index of said composition is greater than 550 volts, measured in accordance with the International Electrotechnical Commission standard IEC 60112/3, the UL 94 classification of said composition is V-0 at a thickness of from 3.2 mm to 0.4 mm, and the Glow Wire Flammability Index of said composition is 960 C. for a thickness of from 0.75 to 3 mm in accordance with IEC 60695-2-12.

7-8. (canceled)

9. The flame-retardant polyamide composition as claimed in claim 1, wherein the polyamide (PA) is selected from the group consisting of PA 6, PA 6,6, PA 4,6, PA 12, PA 6,10, PA 6T/66, PA 6T/6, PA 4T, PA 9T, PA 10T, polyamide copolymers, polyamide blends, and combinations thereof.

10. The flame-retardant polyamide composition as claimed in claim 1, wherein component A is nylon-6,6 or a copolymer or polymer blend made of nylon-6,6 and nylon-6.

11. The flame-retardant polyamide composition as claimed in claim 1, wherein component A is composed of at least 75% by weight of nylon-6,6 and at most 25% by weight of nylon-6.

12. The flame-retardant polyamide composition as claimed in claim 1, wherein component A is a blend of nylon-6,6 and of an amorphous, semiaromatic polyamide.

13. The flame-retardant polyamide composition as claimed in claim 1, wherein R.sup.1 and R.sup.2 are identical or different and are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl and/or phenyl.

14. The flame-retardant polyamide composition as claimed in claim 1, wherein in the case of component B R.sup.3 is methylene, ethylene, n-propylene, isopropylene, n-butylene, tert-butylene, n-pentylene, n-octylene, or n-dodecylene; phenylene, or naphthylene; methylphenylene, ethylphenylene, tert-butylphenylene, methylnaphthylene, ethylnaphthylene, or tert-butylnaphthylene; phenylmethylene, phenylethylene, phenylpropylene or phenylbutylene.

15. The flame-retardant polyamide composition as claimed in claim 1, wherein the salt of phosphorous acid (component C) has the formula [HP(O)O.sub.2].sup.2M.sup.m+ in which M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, and/or K and m is a number sufficient to provide ionic balance.

16. The flame-retardant polyamide composition as claimed in claim 1, wherein the salt of phosphorous acid (component C) is 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.1.5*12H.sub.2O, Al.sub.2(HPO.sub.3).sup.3*xAl.sub.2O.sub.3*nH.sub.2O, where x=2.271, and/or Al.sub.4H.sub.6P.sub.16O.sub.18.

17. The flame-retardant polyamide composition as claimed in claim 1, wherein the salt of phosphorous acid is aluminum phosphite of the formulae (I), (II), and/or (III), where formula (I) is Al.sub.2(HPO.sub.3).sub.3x(H.sub.2O).sub.q, q is from 0 to 4, formula (II) is Al.sub.2.00M.sub.z(HPO.sub.3).sub.y(OH).sub.vx(H.sub.2O).sub.w, in which M is alkali metal ions, z is from 0.01 to 1.5, and y is from 2.63 to 3.5, and v is from 0 to 2, and w is from 0 to 4, and formula (III) is Al.sub.2.00(HPO.sub.3).sub.u(H.sub.2PO.sub.3).sub.tx(H.sub.2O).sub.s, in which u is from 2 to 2.99, and t is from 2 to 0.01, and s is from 0 to 4, and/or is a mixture of aluminum phosphite of the formula (I) with sparingly soluble aluminum salts and with foreign nitrogen-free ions, or a mixture of aluminum phosphite of the formula (III) with aluminum salts, or is 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.1.5*12H.sub.2O, or Al.sub.2(HPO.sub.3).sup.3*xAl.sub.2O.sub.3*nH.sub.2O, where x=2.271, and/or Al.sub.4H.sub.6P.sub.16O.sub.18.

18. The flame-retardant polyamide composition as claimed in claim 1, wherein the average particle size of component C is from 0.2 to 100 m.

19. The flame-retardant polyamide composition as claimed in claim 1, wherein the reinforcing filler is glass fibers.

20. The flame-retardant polyamide composition as claimed in claim 1, wherein component E is a derivative of an aromatic di- or tricarboxylic (ester) amide.

21. The flame-retardant polyamide composition as claimed in claim 1, wherein component E is N,N-bispiperidinyl-1,3-benzenedicarboxamide and/or N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,3-benzenedicarboxamide.

22. The flame-retardant polyamide composition as claimed in claim 1, wherein the phosphonites (component F) are those of the general structure R[P(OR.sub.1).sub.2].sub.m where R is a mono- or polyvalent aliphatic, aromatic, or heteroaromatic organic moiety, and R.sub.1 is a system of the structure ##STR00007## or the two moieties R.sub.1 form a bridging group of the structure ##STR00008## where A is a direct bond, O, S, C.sub.1-C.sub.18-alkylene (linear or branched), C.sub.1-C.sub.18-alkylidene (linear or branched), and R.sub.2 is mutually independently C.sub.1-C.sub.12-alkyl (linear or branched), C.sub.1-C.sub.12-alkoxy, C.sub.5-C.sub.12-cycloalkyl, and n is from 0 to 5, and m is from 1 to 4.

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

24. The flame-retardant polyamide composition as claimed in claim 1, wherein said item is a molding, injection-molded part, extruded composition, or extruded part.

25. (canceled)

Description

EXAMPLE

1. Components Used

[0179] commercially available polyamides (component A):

[0180] nylon-6,6 (PA 6.6-GR): Ultramid A27 (BASF AG, D)

[0181] nylon-6,T/6,6: Zytel HTN FE 8200 (DuPont, USA)

[0182] nylon-6: Durethan B29 (Lanxess AG, D)

[0183] nylon-6,T/6,I (amorphous): Grivory G21, EMS Grivory, CH

[0184] nylon-6,10: Ultramid S, BASF AG, D

[0185] flame retardant (component B):

[0186] aluminum salt of diethylphosphinic acid, hereinafter called DEPAL

[0187] flame retardant (component C):

[0188] aluminum salt of phosphorous acid, hereinafter called PHOPAL

[0189] comparison: MPP, melamine polyphosphate, Melapur 200/70, BASF AG, D

[0190] component D:

[0191] PPG HP 3610 glass fibers, diameter 10 m, length 4.5 mm (PPG, NL)

[0192] Aromatic di- or tricarboxylic esters/amides (component E):

[0193] Nylostab S-EED (Clariant Produkte (Deutschland) GmbH, D)

[0194] (* Nylostab S-EED is N,N-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,3-benzenedicarboxamide)

[0195] phosphonites (component F):

[0196] Sandostab P-EPQ, Clariant Produkte (Deutschland) GmbH, D

[0197] wax components (component G):

[0198] Licomont CaV 102 (Ca salt of montan wax acid), Clariant Produkte (Deutschland) GmbH, D

[0199] Licowax E (ester of montan wax acid), Clariant Produkte (Deutschland) GmbH, D

2. Production, Processing, and Testing of Flame-Retardant Polyamide Molding Compositions

[0200] The flame retardant components were mixed in the ratio stated in the table with the phosphonite, and with the lubricants and stabilizers, and incorporated by way of the side feed of a twin-screw extruder (Leistritz ZSE 27/44D) at temperatures of from 260 to 310 C. into PA 6.6 and, respectively, at from 250 to 275 C. into PA 6. The glass fibers were added by way of a second side feed. The homogenized polymer strand was drawn off, cooled in a water bath and then pelletized.

[0201] After adequate drying, the molding compositions were processed in an injection-molding machine (Arburg 320 C Allrounder) at melt temperatures of from 250 to 300 C. to give test specimens, and tested and classified for flame retardancy on the basis of the UL 94 test (Underwriters Laboratories).

[0202] The flowability of the molding compositions was determined via determination of melt volume index (MVR) for 275 C./2.16 kg. Higher MVR values mean better flowability in the injection-molding process. A sharp rise in MVR value can also, however, indicate polymer degradation.

[0203] All of the experiments of the present series were, unless otherwise stated, carried out under identical conditions for reasons of comparability (temperature programs, screw geometries, injection-molding parameters, etc.).

[0204] Inventive examples IE1-IE3 list the results where the flame retardant-stabilizer mixtures of the invention were used. All quantities are stated as % by weight and are based on the plastics molding composition inclusive of the flame retardants, additives, and reinforcing materials.

TABLE-US-00001 TABLE 1 PA 66 GF 30 Results of experiments. CE1-CE3 are comparative examples, and IE1 to IE3 are polyamide molding compositions of the invention CE1 CE2 CE3 IE1 IE2 IE3 A: Nylon-6,6 49.55 49.55 49.55 49.55 39.55 49.30 A: Nylon-6 10 D: HP3610 30 30 30 30 30 30 glass fibers B: DEPAL 20 12 15 15 17 17 C: PHOPAL 5 3 7 MPP 8 5 E: SEED 0.25 G: CaV 102 0.25 0.25 0.25 0.25 0.25 0.25 F: P-EPQ 0.20 0.20 0.20 0.20 0.20 0.20 UL 94 0.4 mm V-1 V-0 V-1 V-0 V-0 V-0 GWFI [ C.] 850 960 960 960 960 960 MVR 275 4 21 12 5 13 12 C./2.16 kg Efflorescence* none signif- slight none none none icant Color white gray gray white white white Surface rough rough rough rough smooth smooth CTI [volts] 600 550 550 600 600 600 Impact 60 63 62 61 60 63 resistance [kJ/m.sup.2] Notched impact 12 11 12 12 12 14 resistance [kJ/m.sup.2] *14 days, 100% humidity, 70 C.

[0205] Only the combination of the invention of polyamide, glass fibers, DEPAL, and PHOPAL gives polyamide molding compositions which achieve the UL 94 fire classification V-0 at 0.4 mm and at the same time have CTI 600 volts, impact resistance greater than 60 kJ/m.sup.2, notched impact resistance greater than 10 kJ/m.sup.2, and exhibit no discoloration and no efflorescence. Addition of nylon-6 (inventive example IE2) and addition of Nylostab SEED (inventive example IE3) moreover produces better flowability (higher MVR) and a more attractive surface. Use of DEPAL without PHOPAL (CE1) does not achieve V-0, and although the combination of DEPAL with MPP achieves V-0 the polyamide molding composition exhibits discoloration and efflorescence. The CTI achieved is moreover not 600V.

TABLE-US-00002 TABLE 2 PA 6 GF 30 Results of experiments. CE4-CE6 are comparative examples, and IE4 to IE7 are polyamide molding compositions of the invention CE4 CE5 CE6 IE4 IE5 IE6 A: Nylon-6 49.55 49.55 49.55 49.55 49.55 49.30 D: HP3610 30 30 30 30 30 30 glass fibers B: DEPAL 20 12 15 15 17 17 C: PHOPAL 5 3 7 MPP 8 5 E: SEED 0.25 G: Wax E 0.25 0.25 0.25 0.25 0.25 0.25 F: P-EPQ 0.20 0.20 0.20 0.20 0.20 0.20 UL 94 0.4 mm V-1 V-0 V-1 V-1 V-0 V-0 MVR 250 5 12 9 5 5 11 C./2.16 kg Efflorescence* none signif- slight none none none icant Color white gray gray white white white Surface rough rough rough rough rough smooth CTI [volts] 600 550 500 600 600 600 Impact 61 59 60 63 63 65 resistance [kJ/m.sup.2] Notched impact 11 9.8 10 11 11 14 resistance [kJ/m.sup.2] *14 days, 100% humidity 70 C.

[0206] A similar picture is revealed by the experiments in nylon-6: only the combination of the invention of nylon-6 with glass fibers, DEPAL, PHOPAL, and SEED gives molding compositions which simultaneously have UL 94 V-0 at 0.4 mm, CTI 600V, no color changes and no efflorescence, good flowability, and good mechanical properties.

TABLE-US-00003 TABLE 3 Nylon-6, 6/6, T/6, I blends and nylon-6,10 CE7 CE8 IE7 IE8 IE9 IE10 A1: Nylon-6,6 35.55 35.55 34.30 A2: Nylon-6, T/6, I 15 15 15 A3: Nylon-6,10 49.55 49.55 49.30 D: HP3610 glass fibers 30 30 30 30 30 30 B: DEPAL 15 12 15 15 15 15 C: PHOPAL 5 5 5 5 MPP 5 8 E: SEED 0.25 0.25 G: CaV 102 0.25 0.25 0.25 0.25 0.25 0.25 F: P-EPQ 0.20 0.20 0.20 0.20 0.20 0.20 UL 94 0.4 mm V-1 V-0 V-0 V-0 V-0 V-0 MVR 275 C./2.16 kg 25 23 7 6 12 15 Efflorescence* significant significant none none none none Color white gray white white white white Surface rough rough rough rough smooth smooth CTI [volts] 600 550 550 600 600 600 Impact resistance [kJ/m.sup.2] 60 65 62 61 60 63 Notched impact resistance 12 13 12 12 12 14 [kJ/m.sup.2] *14 days, 100% humidity 70 C.

[0207] The picture revealed by the experiments in nylon-6,10 is similar to that for PA6: only the combination of the invention of nylon-6 with glass fibers, DEPAL, PHOPAL, and SEED gives molding compositions which simultaneously have UL 94 V-0 at 0.4 mm, CTI 600V, no color changes and no efflorescence, good flowability, and good mechanical properties.

[0208] In the blend of nylon-6,6 with an amorphous, semiaromatic polyamide (6T/6I), onset of decomposition, discernible from very high MVR, is observed with DEPAL+MPP. In contrast, the combination of the invention of DEPAL and PHOPAL exhibits no decomposition, UL 94 V-0, and CTI 600 V. Addition of SEED can improve flowability and surface quality.

TABLE-US-00004 TABLE 4 Experimental results from PA6T/66 GF 30 CE9 CE10 IE11 IE12 A: Nylon-6,T/6,6 57.55 54.55 57.55 54.30 D: HP3610 glass fibers 30 30 30 30 B: DEPAL 12 12 12 12 MPP 3 C: PHOPAL 3 3 D: SEED 0.25 G: CaV 102 0.25 0.25 0.25 0.25 E: P-EPQ 0.20 0.20 0.20 0.20 UL 94 0.8 mm V-1 n.d.* V-0 V-0 CTI [V] 600 n.d.* 600 600 MVR 325 C./2.16 kg 13 n.d. 8 17 Impact resistance [kJ/m.sup.2] 40 n.d. 45 47 Notched impact resistance 8 n.d. 12 13 [kJ/m.sup.2] *Decomposition during extrusion, no polymer strand obtained

[0209] The DEPAL+MPP system cannot be used in nylon-6,T/6,6: severe decomposition is observed even before compounding has concluded. The polymer strand foams, and no pelletization is possible. In contrast, the polyamide of the invention with DEPAL, PHOPAL, and glass fibers provides good processing and achieves UL 94 V-0 and CTI 600 V. Here again, addition of SEED can improve flowability and surface quality.