FLAME-RETARDANT GRAY POLYAMIDE COMPOSITIONS AND USE THEREOF

Abstract

The invention relates to flame-retardant polyamide compositions comprising polyamide having a melting point of not more than 290° C. as component A, fillers and/or reinforcers as component B, phosphinic salt of the formula (I) as component C

##STR00001## in which R.sub.1 and R.sub.2 are ethyl, M is Al, Fe, TiO.sub.p or Zn, m is 2 to 3, and

p=(4−m)/2 compound selected from the group of the Al, Fe, TiO.sub.p and Zn salts of ethylbutylphosphinic acid, of dibutylphosphinic acid, of ethylhexylphosphinic acid, of butylhexylphosphinic acid and/or of dihexylphosphinic acid as component D phosphonic salt of the formula as component E

##STR00002## in which R.sub.3 is ethyl, Met is Al, Fe, TiO.sub.q or Zn, n is 2 to 3, and

q=(4−n)/2 melamine polyphosphate having an average degree of condensation of 2 to 200 as component F, and gray colorant as component G.

Claims

1. A flame-retardant polyamide composition comprising polyamide having a melting point of not more than 290° C. as component A; fillers and/or reinforcers as component B; phosphinic salt of the formula (I) as component C ##STR00006## in which R.sub.1 and R.sub.2 are ethyl, M is Al, Fe, TiO.sub.p or Zn, m is 2 to 3, and
p=(4−m)/2; compound selected from the group of the Al, Fe, TiO.sub.p and Zn salts of ethylbutylphosphinic acid, of dibutylphosphinic acid, of ethylhexylphosphinic acid, of butylhexylphosphinic acid and/or of dihexylphosphinic acid as component D; phosphonic salt of the formula II as component E ##STR00007## in which R.sub.3 is ethyl, Met is Al, Fe, TiO.sub.q or Zn, n is 2 to 3, and
q=(4−n)/2; melamine polyphosphate having an average degree of condensation of 2 to 200 as component F; and gray colorant as component G.

2. The flame-retardant polyamide composition as claimed in claim 1, wherein M and Met are Al, m and n are 3, and component D is an aluminum salt.

3. The flame-retardant polyamide composition as claimed in claim 1, wherein the proportion of component A is 25% to 95% by weight, the proportion of component B is 1% to 45% by weight, the proportion of component C is 1% to 35% by weight, the proportion of component D is 0.01% to 3% by weight, the proportion of component E is 0.001% to 1% by weight, the proportion of component F is 1% to 25% by weight, and the proportion of component G is 0.01% to 20% by weight, where the percentages are based on the total amount of the polyamide composition.

4. The flame-retardant polyamide composition as claimed in claim 3, wherein the proportion of component A is 25% to 75% by weight, the proportion of component B is 20% to 40% by weight, the proportion of component C is 5% to 20% by weight, the proportion of component D is 0.05% to 1.5% by weight, the proportion of component E is 0.01% to 0.6% by weight, the proportion of component F is 2% to 10% by weight, and the proportion of component G is 0.1% to 8% by weight, where the percentages are based on the total amount of the polyamide composition.

5. The flame-retardant polyamide composition as claimed in claim 1, wherein the polyamide composition comprises inorganic phosphonate as further component H.

6. The flame-retardant polyamide composition as claimed in claim 5, wherein the inorganic phosphonate is a compound of the formula (III) ##STR00008## in which Me is Fe, TiO.sub.r, Zn or especially Al, o is 2 to 3, and
r=(4−o)/2, where the compound of the formula III is present in an amount of 0.005% to 10% by weight, especially in an amount of 0.02% to 5% by weight, based on the total amount of the polyamide composition.

7. The flame-retardant polyamide composition as claimed in claim 1, which has a comparative tracking index measured by International Electrotechnical Commission Standard IEC-60112/3 of not less than 500 volts.

8. The flame-retardant polyamide composition as claimed in claim 1, which attains a V-0 assessment according to UL94 from thickness 3.2 mm to 0.4 mm.

9. The flame-retardant polyamide composition as claimed in claim 1, which has a glow wire flammability according to IEC-60695-2-12 of not less than 960° C. at thickness 0.75-3 mm.

10. The flame-retardant polyamide composition as claimed in claim 1, wherein component A is one or more polyamides selected from the group consisting of PA 6, PA 6,6, PA 4,6, PA 12, PA 6,10.

11. The flame-retardant polyamide composition as claimed in claim 10, wherein component A is nylon-6,6 or comprises polymer mixtures of nylon-6,6 and nylon-6.

12. The flame-retardant polyamide composition as claimed in claim 11, wherein component A consists to an extent of at least 75% by weight of nylon-6,6 and to an extent of at most 25% by weight of nylon-6.

13. The flame-retardant polyamide composition as claimed in claim 1, wherein glass fibers are used as component B.

14. The flame-retardant polyamide composition as claimed in claim 1, wherein components C, D, E and F are in particulate form, where the median particle size d.sub.50 of these components is 1 to 100 μm.

15. The flame-retardant polyamide composition as claimed in claim 1, wherein the average degree of condensation of the melamine polyphosphate is 2 to 100.

16. The flame-retardant polyamide composition as claimed in claim 1, wherein the melamine polyphosphate has a breakdown temperature of not less than 320° C.

17. The flame-retardant polyamide composition as claimed in claim 1, wherein component G is a blend of black and white pigments or dyes or is a blend of complementary-colored pigments or dyes.

18. The flame-retardant polyamide composition as claimed in claim 17, wherein component G is a blend of white pigments with black pigments or dyes, where the white pigments are selected from the group of zinc oxide, zinc sulfide, white lead, lithopone, antimony white, barium sulfate and/or titanium dioxide and where the black pigments or dyes are selected from the group of carbon black, graphite, graphene, nigrosins, bone charcoal, black color pigments and of combinations of complementary-colored red to yellow pigments with green, blue or violet pigments or mixtures of two or more of these compounds.

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

20. The use of the polyamide compositions as claimed in claim 1 for production of fibers, films and shaped bodies, especially for applications in the electricals and electronics sector.

Description

EXAMPLES 1-5, 1A, 1B, 5A AND COMPARATIVE EXAMPLES C1-C3 WITH PA 6,6

[0225] The results of the experiments with PA 6,6 molding compounds are listed in the examples adduced in the table which follows. All amounts are reported as % by weight and are based on the polyamide molding compound including the flame retardants, additives and reinforcers.

TABLE-US-00001 TABLE 1 PA 6,6 GF 30 Test results (1-5, 1a, 1b, 5a inventive; C1-C3 comparisons; n.d. = not determined) Example No. 1 2 3 4 5 V1 V2 V3 V4 V5 1a 1b 5a A: Nylon-6,6 51   52.5 51 48 51  51 51 51 51 51 51  48 48  B: GF, HP3610 30 30 30 30 30  30 30 30 30 30 30  30 30  C + D + E: FM 1 12 — — — — — — — — — 8 16 — C + D + E: FM 2 — 12 — — 10  — 12 — — — — — 10  C + D + E: FM 3 — — 12 — — — — — — — — — — C + D + E: FM 4 — — — 12 — — — — — — — — — C: FM 5 — — — — — — — — — 12 — — — C + E: FM 6 — — — — — 12 — — — — — — — H: FM 7 — — — — 2 — — — — — — — 5 F: FM 8  5  5  5  5 5  5 —  5  5  5 9  4 5 Comparison: FM 9 — — — — — —  5 — — — — — — Comparison: FM 10 — — — — — — — 12 — — — — — Comparison: FM 11 — — — — — — — — 12 — — — — G:  2   0.5  2  5 2  2  2  2  2  2 2  2 2 UL 94 0.4 mm/time V-0/25 V-0/20 V-0/25 V-0/40 V-0/10 V-0/45 n.d. V-0/40 V-0/35 V-0/50 V-0/28 V-0/28 V-0/10 [sec.] GWFI [° C.] 960  960  960  960   960 960  n.d. 850  900  960  960  960  960 CTI [volts] 600  600  600  600   600 500  n.d. 600  450  500  600  600  600 Color  1  1  1  1 1  1 n.d.  3  2  1 1  1 1

[0226] The inventive polyamide compositions of examples 1 to 5, 1a, 1 b and 5a are molding compounds which attain the UL94 V-0 fire class at 0.4 mm, simultaneously have CTI 600 volts and GWFI 960° C., and show a consistently gray color without any reddish tinge. The addition of component H in examples 5 and 5a leads to another improvement in flame retardancy, expressed by a reduced afterflame time.

[0227] The omission of component D in comparative example C1 resulted not only in a prolonged afterflame time but also in a reduction in the CTI value compared to examples 1-4.

[0228] The replacement of component F by a component having a lower degree of condensation in comparative example C2 had the result that the polyamide strand foamed in the course of production and no measurements could be undertaken.

[0229] The use of red phosphorus in place of components C, D and E in comparative example C3 led to a distinct reddish tinge in the color of the shaped bodies.

[0230] The use of bromopolystyrene/antimony trioxide masterbatch in PA 6 in place of components C, D and E in comparative example C4 likewise led to a distinct reddish tinge in the color of the shaped bodies. Moreover, the CTI value was reduced considerably.

[0231] The omission of components D and E in comparative example C5 resulted not only in a prolonged afterflame time but also in a reduction in the CTI value compared to examples 1-4.

EXAMPLES 6-10 AND COMPARATIVE EXAMPLES C6-C10 WITH PA 6,6/PA 6

[0232] The results of the experiments with PA 6/PA 6,6 molding compounds are listed in the examples adduced in the table which follows. All amounts are reported as % by weight and are based on the polyamide molding compound including the flame retardants, additives and reinforcers.

TABLE-US-00002 TABLE 2 PA 6/PA 6,6 GF 30 Test results (6-10 inventive; C6-C10 comparisons; n.d. = not determined) Example No. 6 7 8 9 10 V6 V7 V8 V9 V10 A: Nylon-6,6 36 36 36 36 36 36 36 36 36 36 A: Nylon 6 15 15 15 15 15 15 15 15 15 15 B: GF, HP3610 30 30 30 30 30 30 30 30 30 30 C + D + E: FM 1 12 — — — — — — — — — C + D + E: FM 2 — 12 — — 10 — 12 — — — C + D + E: FM 3 — — 12 — — — — — — — C + D + E: FM 4 — — — 12 — — — — — — C: FM 5 — — — — — — — — — 12 C + E: FM 6 — — — — — 12 — — — — H: FM 7 — — — —  2 — — — — — F: FM 8  5  5  5  5  5  5 —  5  5  5 Comparison: FM 9 — — — — — —  5 — — — Comparison: FM 10 — — — — — — — 12 — — Comparison: FM 11 — — — — — — — — 12 — G:  2  2  2  2  2  2  2  2  2  2 UL 94 0.4 mm/time V-0/29 V-0/23 V-0/44 V-0/28 V-0/14 V-0/47 n.d. V-0/50 V-0/35 V-0/50 [sec.] GWFI [° C.] 960  960  960  960  960  960  n.d. 850  900  960  CTI [volts] 600  600  600  600  600  500  n.d. 600  450  500  Color  1  1  1  1  1  1 n.d.  3  2  1

[0233] The inventive polyamide compositions of examples 6 to 10 are molding compounds which attain the UL94 V-0 fire class at 0.4 mm, simultaneously have CTI 600 volts and GWFI 960° C., and show a consistently gray color without any reddish tinge. The addition of component H in example 10 leads to another improvement in flame retardancy, expressed by a reduced afterflame time.

[0234] The omission of component D in comparative example C6 resulted not only in a prolonged afterflame time but also in a reduction in the CTI value compared to examples 6-9.

[0235] The replacement of component F by a component having a lower degree of condensation in comparative example C7 had the result that the polyamide strand foamed in the course of production and no measurements could be undertaken.

[0236] The use of red phosphorus in place of components C, D and E in comparative example C8 led to a distinct reddish tinge in the color of the shaped bodies.

[0237] The use of bromopolystyrene/antimony trioxide masterbatch in PA 6 in place of components C, D and E in comparative example C9 likewise led to a distinct reddish tinge in the color of the shaped bodies. Moreover, the CTI value was reduced considerably.

[0238] The omission of components D and E in comparative example C10 resulted not only in a prolonged afterflame time but also in a reduction in the CTI value compared to examples 6-9.

COMPARATIVE EXAMPLES C11-C17 WITH PA 6T/6,6

[0239] The results of the experiments with PA 6T/6,6 molding compounds are listed in the examples adduced in the table which follows. All amounts are reported as % by weight and are based on the polyamide molding compound including the flame retardants, additives and reinforcers.

TABLE-US-00003 TABLE 3 PA 6T/6,6 GF 30 test results (n.d. = not determined) Example No. C11 C12 C13 C14 C15 C16 C17 A: Nylon-6T/6,6 51 51 51 51 51 51 51 B: HP3610 glass fibers 30 30 30 30 30 30 30 C + D + E: FM 1 12 — — — — — — C + D + E: FM 2 — 12 — — 10 — — C + D + E: FM 3 — — 12 — — — — C + D + E: FM 4 — — — 12 — — — C: FM 5 — — — — — — 12 H: FM 7 — — — —  2 — — F: FM 8  5  5  5  5  5  5  5 Comparison: FM 10 — — — — — 12 — G:  2  2  2  2  2  2  2 UL 94 0.4 mm / time n.d. n.d. n.d. n.d. n.d. n.d. n.d. [sec.] GWFI [° C.] n.d. n.d. n.d. n.d. n.d. n.d. n.d. MVR [cm3/10 min.] n.d. n.d. n.d. n.d. n.d. n.d. n.d. Color n.d. n.d. n.d. n.d. n.d. n.d. n.d. CTI [volts] n.d. n.d. n.d. n.d. n.d. n.d. n.d.

[0240] None of the PA molding compounds from comparative examples 011-017 produced test specimens since the PA molding compounds were found not to be workable. The polyamide strands foamed up in the course of production and it was not possible to produce any test specimens suitable for the measurements.

COMPARATIVE EXAMPLES C18-C22 WITH PA 6,6

[0241] It is apparent from table 4 that only with the inventive combination of flame retardants is it possible to produce polyamide compositions having the properties of V-0, GWFI 960, CTI 600 and a gray color without a reddish tinge. With melamine polyphosphate alone or with bromopolystyrene with antimony trioxide it is possible to establish V-0, but not a deep gray color.

TABLE-US-00004 TABLE 4 Nylon-6,6 GF comparative examples, results (n.c. = not classifiable) Example No. C18 C19 C20 C21 C22 A: Nylon-6,6 43 51 43 51 43 B: HP3610 glass fibers 30 30 30 30 30 Comparison: FM 8 25 17 5 5 5 Comparison: FM 9 — — 25 17 — Comparison: FM 11 25 G: 2 2 2 2 2 UL 94 0.4 mm/time [sec.] V-0/45 n.c. V-0/43 n.c. V-0/23 GWFI [° C.] 960 750 960 700 960 Color 2 2 2 2 2 CTI [volts] 500 500 350 500 350