Glow wire resistant polyamides

Abstract

The invention relates to the use of thermal plastic molding compositions comprising TABLE-US-00001 A) from 10 to 97% by weight of a thermoplastic polyamide, B) from 1 to 10% by weight of red phosphorus, C) from 0.15 to 6% by weight of a dialkylphosphinic salt, where the ratio of B) to C) is from 6:1 to 6:4, D) from 1 to 10% by weight of an ethylene copolymer as impact modifier comprisingas component D) a copolymer of D.sub.1) from 40 to 98% by weight of ethylene D.sub.2) from 2 to 40% by weight of a (meth)acrylate having from 1 to 18 carbon atoms, or/and D.sub.3) from 0 to 20% by weight of functional monomers selected from the group of the ethylenically unsaturated mono- or dicarboxylic acids or of the carboxylic anhydrides or epoxide groups, or a mixture of these, or an ethylene-(meth)acrylic acid copolymer neutralized with zinc up to an extent of 72%, E) from 0 to 5% by weight of talc powder with a median particle size (d.sub.50 value) below 7.5 μm, F) from 0 to 60% by weight of further additional substances,
where the sum of the percentages by weight of components A) to F) is 100%, for the production of flame-retardant, glow-wire-resistant moldings.

Claims

1. Use of a thermoplastic molding composition, the use comprising providing a molding composition comprising A) from 10 to 97% by weight of a thermoplastic polyamide, B) from 1 to 10% by weight of red phosphorus, C) from 0.15 to 6% by weight of a dialkylphosphinic salt, where the ratio of B) to C) is from 6:1 to 6:4, D) from 1 to 10% by weight of an ethylene copolymer as impact modifier, comprising as component D) a copolymer of D.sub.1) from 40 to 98% by weight of ethylene D.sub.2) from 2 to 40% by weight of a (meth)acrylate having from 1 to 18 carbon atoms, or/and D.sub.3) from 0 to 20% by weight of functional monomers selected from the group of the ethylenically unsaturated mono- or dicarboxylic acids or of the carboxylic anhydrides or epoxide groups, or a mixture of these, or an ethylene-(meth)acrylic acid copolymer neutralized with zinc up to an extent of 72%, E) from 0 to 5% by weight of talc powder with a median particle size (d.sub.50 value) below 7.5 μm, F) from 0 to 60% by weight of further additional substances selected from the group consisting of fibrous fillers, particulate fillers, lubricants, acid scavengers, antioxidants, nigrosins, oxidation retarders, heat stabilizers, ultraviolet stabilizers, mold-release agents, colorants, nucleating agents, and combinations thereof, where the sum of the percentages by weight of components A) to F) is 100% and the molding composition is free from zinc borate, in a production of flame-retardant, glow-wire-resistant moldings.

2. The use according to claim 1, where the molding compositions comprise A) from 10 to 97% by weight B) from 1 to 10% by weight C) from 0.15 to 6% by weight D) from 1 to 10% by weight E) from 0.0015 to 5% by weight F) from 0 to 60% by weight.

3. The use according to claim 1, where component C comprises ##STR00006## where R.sup.1 and R.sup.2 are mutually independently methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, M=Mg, Ca, Al, Ti, Zn, Fe, Li, Na, K, or a protonated nitrogen base x=from 1 to 4 n=from 1 to 4.

4. The use according to claim 1, where component C) comprises zinc diethylphosphinate and/or Al diethylphosphinate.

5. The use according to claim 1, where the ratio of C) to E) is from 1:1 to 2:0.002.

6. The use according to claim 1, comprising as component D a copolymer of D.sub.1) from 50 to 69.9% by weight of ethylene D.sub.2) from 30 to 40% by weight of a (meth)acrylate having from 1 to 18 carbon atoms D.sub.3) from 0.1 to 10% by weight of functional monomers according to claim 1, where the sum of the percentages by weight D.sub.1) to D.sub.3) is 100%.

7. The use according to claim 1, in which component D.sub.3) comprises acrylic acid, maleic anhydride, glycidyl (meth)acrylate, or a mixture thereof.

8. The use according to claim 1, wherein a BET surface area in accordance with ISO 4652 of component E) is less than 13 m.sup.2/g.

9. A molding obtained according to the use of claim 1, which passes the GWFI (glow-wire flammability index) test in accordance with DIN EN 60 695-2-12 at 960° C.

Description

EXAMPLES

(1) The following components were used:

(2) Component A:

(3) Nylon-6,6 with an intrinsic viscosity IV of 150 ml/g, measured on a 0.5% by weight solution in 96% by weight sulfuric acid at 25° C. in accordance with ISO 307 (the material used being Ultramid® A27 from BASF SE).

(4) Component B/1:

(5) 50% concentrate of red phosphorus of median particle size (d.sub.50) from 10 to 30 μm in nylon-6.

(6) Component B/2:

(7) Red phosphorus of median particle size (d.sub.50) from 20 to 25 μm.

(8) Component C/1:

(9) Aluminum diethylphosphinate (Exolit® OP1230 Clariant Produkte GmbH).

(10) Component C/2:

(11) Zinc diethylphosphinate (Exolit® OP950 Clariant Produkte GmbH).

(12) Component C/3:

(13) Calcium hypophosphite (Sigma-Aldrich Co.) (comparison)

(14) Component C/4 (for comparison)

(15) Melamine polyphosphate (Melapur® 200/70 BASF SE)

(16) Component D/1:

(17) An olefin polymer of: 59.8% by weight of ethylene, 35% by weight of n-butyl acrylate, 4.5% by weight of acrylic acid, and 0.7% by weight of maleic anhydride with a melt index MFI (190/2.16) of 10 g/10 min. The copolymer was produced via copolymerization of the monomers at elevated temperature and elevated pressure.

(18) Component D/2:

(19) Ethylene-1-octene-maleic anhydride copolymer (Fusabond® 598D ex E.I. DuPont de Nemours and Company) (comparison).

(20) Component E/1:

(21) Talc powder with a median particle size D.sub.50 of 2.3 μm and with a specific BET surface area of 9.5 m.sup.2/g (measured in accordance with ISO 4652) (Finntalc M05N ex Mondo Minerals B.V.).

(22) Component E/2:

(23) Talc powder with a median particle size D.sub.50 of 1.7 μm and with a specific BET surface area of 12 m.sup.2/g (measured in accordance with ISO 4652) (Microtalc IT EXTRA ex Mondo Minerals B.V.).

(24) Component E/3: Talc powder with a median particle size D.sub.50 of 7.4 μm and with a specific BET surface area of 4.0 m.sup.2/g (measured in accordance with ISO 787/11) (Tital 4591ex Ankerpoort N.V.).

(25) Component F/1:

(26) 30% concentrate of a gas black with a specific BET surface area of 180 m.sup.2/g (measured in accordance with DIN 66131) in nylon-6.

(27) Component F/2:

(28) 40% concentrate of nigrosin in nylon-6.

(29) Component F/3:

(30) ZnO:Ca stearate:Irganox® 1098 (2:1:1)

(31) Component F/4:

(32) Standard chopped glass fiber for polyamides, length=4.5 mm, diameter=10 μm.

(33) Production of the Molding Compositions

(34) In order to demonstrate the improvements in phosphorus stability described in the invention, appropriate plastics molding compositions were prepared via compounding. To this end, the individual components were mixed in a ZSK 26 (Berstorff) twin-screw extruder with a throughput of 20 kg/h and at about 270° C. with a flat temperature profile, discharged in the form of strand, cooled until pelletizable, and pelletized.

(35) Tests

(36) The test specimens for the tests listed in table 1 were injection-molded in an Arburg 420C injection-molding machine at a melt temperature of about 270° C. and at a mold temperature of about 80° C.

(37) The test specimens for the stress tests were produced in accordance with ISO 527-2:/1993, and the test specimens for the impact resistance tests were produced in accordance with ISO 179-2/1 eA.

(38) The MVR tests were carried out in accordance with ISO 1133.

(39) The flame retardancy of the molding compositions was determined firstly by the UL 94 V method (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).

(40) Glow-wire resistance GWFI (glow-wire flammability index) was tested in accordance with DIN EN 60695-2-12 on plaques. The GWFI test is a general suitability test for plastics in contact with parts that carry an electrical potential. The temperature determined is the highest at which one of the following conditions is met in three successive tests: (a) no ignition of the specimen or (b) afterflame time or afterglow time 30 s after end of exposure to the glow wire, and no ignition of the underlay.

(41) TABLE-US-00004 TABLE Components [% by wt.] comp1 comp2 comp3 comp4 comp5 comp6 A 46 54 41 46.1 51.5 46.6 B/1 6.6 6.6 6.6 6.6 6.6 12 B/2 — — — — — — F/4 26 26 26 26 26 26 C/1 10 2 10 6.6 3 — C/2 — — — — — — C/3 — — — — — 4 C/4 — — 5 3.3 1.5 — D/1 — — — — — 10 D/2 10 10 10 10 10 — E/1 — — — — — — E/2 — — — — — — E/3 — — — — — — F/1 — — — — — — F/2 — — — — — — F/3 1.4 1.4 1.4 1.4 1.4 1.4 Modulus of elasticity/ 7089 7267 7097 7058 7047 NOT [MPa] EXTRUDABLE Tensile stress at break/ 93 108 99 97 107 [MPa] Tensile strain at break/ 4.3 3.9 3.8 3.5 3.3 [%] Charpy impact 68 70 61 66 68 resistance/[kJ/m.sup.2] MVR 275° C./5 kg/ 20 32 8 14 20 [cm.sup.3/10 min] UL 94 (1.6 mm) n.c. n.c. V-0 V-0 V.0 — UL 94 (0.8 mm) V-1 n.c. V-0 V-1 n.c. — Prot:C/1 ratio 6:18 6:3.6 6:18 6:12 6:5.5 — GWFI 960 (1.5 mm) Failed Failed Passed Passed Passed — Components [% by wt.] 1 2 3 4 5 6 7 8 9 10 11 A 46.6 46.6 46.6 58.6 48.6 48.55 50.6 47.27 53.27 50.6 50.6 B/1 12 12 12 — 12 12 12 12 12 12 12 B/2 — — — 6 — — — — — — — F/4 26 26 26 26 26 26 26 26 26 26 26 C/1 — 4 2 2 2 2 2 2 1 2 2 C/2 4 — — — — — — — — — — C/3 — — — — — — — — — — — D/1 10 10 10 6 10 10 6 6 — 6 6 E/1 — — 2 — 0.002 0.05 2 2 1 — — E/2 — — — — — — — — — 2 — E/3 — — — — — — — — — — 2 F/1 — — — — — — — 3.33 3.33 — — F/2 — — — — — — — — 2.0 — — F/3 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 Modulus of elasticity/[MPa] 8337 7393 7871 8137 7299 7239 8563 8377 8377 8344 8302 Tensile stress at break/[MPa] 121 112 118 138 118 121 132 128 132 129 129 Tensile strain at break/[%] 3.6 4.7 4.1 3.8 3.5 3.7 3.2 3.4 3.0 3.3 3.4 Charpy impact resistance/ 84 75 77 71 72 71 69 72 66 70 68 [kJ/m.sup.2] MVR 275° C./5 kg/[cm.sup.3/ — 13 12 40 — — 29 21 24 28 26 10 min] UL 94 (1.6 mm) V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 V-0 UL 94 (0.8 mm) — V-0 V-0 V-0 — — V-0 V-0 V-0 V-0 V-0 Prot:C/1 resp. C/2 ratio 6:4 6:4 6:2 6:2 6:2 6:2 6:2 6:2 6:1 6:2 6:2 GWFI 960 (1.5 mm) Passed Passed Passed Passed Passed Passed Passed Passed Passed Passed Passed