Polyamide mixtures comprising polyamides containing pyrrolidone

Abstract

The invention relates to thermoplastic molding compositions comprising A) 10 to 98 wt % of a thermoplastic polyamide other than B), B) 1 to 50 wt % of a thermoplastic polyamide comprising units derived from 2-pyrrolidone, C) 0 to 40 wt % of a halogen-free flame retardant, D) 0 to 60 wt % of a fibrous or particulate filler or mixtures thereof, E) 0 to 30 wt % of further added substances,
wherein the weight percentages A) to E) sum to 100%.

Claims

1. A thermoplastic molding composition comprising A) 10 to 98 wt % of a thermoplastic polyamide other than B), B) 1 to 50 wt % of a thermoplastic polyamide comprising 2-pyrrolidone units as repeating units, said 2-pyrrolidone units being bonded to the further repeat units, C) 0 to 40 wt % of a halogen-free flame retardant, D) 0 to 60 wt % of a fibrous or particulate filler or mixtures thereof, E) 0 to 30 wt % of further added substances, wherein the weight percentages A) to E) sum to 100%.

2. The thermoplastic molding composition according to claim 1 comprising: A) 10 to 98 wt %, B) 1 to 30 wt %, C) 1 to 40 wt %, D) 0 to 50 wt %, E) 0 to 30 wt %.

3. The thermoplastic molding composition according to claim 1 in which component B) is obtainable by polycondensation of a monomer mixture, based on 100 mol % of B1) and B2), of B1) 12.5 to 50 mol % of itaconic acid, wherein 0 to 37.5 mol % of further dicarboxylic acids (distinct from itaconic acid) may be present, B2) 12.5 to 50 mol % of at least one diamine comprising an aromatic ring, wherein 0 to 37.5 mol % of further diamines may be present.

4. The thermoplastic molding composition according to claim 3 comprising as component B2) diamines having an aromatic ring selected from the group of m-xylylenediamine, p-xylylenediamine, m- or p-phenylenediamine, 4,4-oxydianiline, 4,4-methylenebisbenzylamine, 1,1-biphenyl-4,4diamine, 2,5-bis(aminomethyl)furan or mixtures thereof.

5. The thermoplastic molding composition according to claim 1 in which component C) is constructed from red phosphorous, phosphinic acid salts, nitrogen-containing flame retardants or mixtures thereof.

6. The thermoplastic molding composition according to claim 1 in which the molecular weight Mn (number-average) of component B) according to GPC (PMMA standard and HFIP eluent) is from 1000 to 30 000 g/mol.

7. The thermoplastic molding composition according to claim 1 in which component C) is constructed from phosphinic acid salts of formula (I) or/and diphosphinic acid salts of formula (II) or polymers thereof ##STR00013## where R.sup.1, R.sup.2 are identical or different and represent hydrogen, C.sub.1-C.sub.6-alkyl, linear or branched, and/or aryl; R.sup.3 represents C.sub.1-C.sub.10-alkylene, linear or branched, C.sub.6-C.sub.10-arylene, -alkylarylene or -arylalkylene; M represents 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 5; n=1 to 4; x=1 to 4.

8. The thermoplastic molding composition according to claim 1 in which component C) is composed of at least one melamine compound.

9. A method for the production of fibers, films, and molded articles comprising the use of a thermoplastic molding composition according to claim 1.

10. A method for reducing a specific heat of combustion and/or a heat release capacity of a molding composition according to claim 1 by at least 5% compared to the molding composition without component B).

11. A fiber, film, or molded article obtained from a thermoplastic molding composition according to claim 1.

Description

EXAMPLES

(1) The following components were employed:

(2) Component A1:

(3) Polyamide 66 having a viscosity number VN of 120 ml/g, measured as a 0.5 wt % solution in 96 wt % of sulfuric acid at 25 C. as per ISO 307 (Ultramid A24 from BASF SE was employed.)

(4) Component A2:

(5) Polyamide 6 having a viscosity number VN of 150 ml/g, measured as a 0.5 wt % solution in 96 wt % of sulfuric acid at 25 C. as per ISO 307 (Ultramid B27 from BASF SE was employed.)

(6) Components B:

(7) The pyrrolidone-containing polymers B) were obtained as per the procedure described in DE4333238A1. The polymers in the examples were produced as follows:

(8) Polymer B1A:

(9) A 1000 ml round-necked flask was charged with 325 g (2.5 mol) of itaconic acid (ICA), 300 g of deionized water and 347 g (2.55 mol) of m-xylylene diamine (MXDA). The reaction mixture was held at 108 C. under reflux for 60 min. The temperature was increased stepwise to 200 C. over one hour to distill-off water and the pressure was then reduced stepwise to 3 mbar to carry out the polycondensation under these conditions over a total of 75 minutes. (in each case with low diamine excess)

(10) The polymer (50 mol % ICA, 50 mol % MXDA) had a Tg of 145 C.,

(11) an Mn/Mw of 4300/10400 g/mol and a VN of 27 ml/g.

(12) Polyamide B2A:

(13) A 1000 ml four-necked flask was charged with 260 g (2 mol) of itaconic acid, 83 g (0.5 mol) of isophthalic acid (IPA), 300 g of DI water and 347 g (2.55 mol) of m-xylidenediamine. The reaction mixture was stirred under reflux for 60 minutes at 108 C. The temperature was then increased to 200 C. over 60 min and water was distilled off. At the same temperature, a pressure of 3 mbar was then applied for 15 minutes.

(14) The polymer (40 mol % ICA, 10 mol % IPA, 50 mol % MXDA) had a Tg of 141 C., a Mn/Mw of 3040/7700 g/mol and a VN of 13 ml/g.

(15) Polyamide B3A:

(16) A 1000 ml four-necked flask was charged with 260 g (2 mol) of a itaconic acid, 73 g (0.5 mol) of adipic acid (AA), 300 g of DI water and 347 g (2.55 mol) of m-xylidenediamine. The reaction mixture was stirred under reflux for 60 minutes at 108 C. The temperature was then increased to 200 C. over 60 min and water was distilled off. At the same temperature, a vacuum of 3 mbar was then applied for 15 minutes.

(17) The polymer (40 mol % ICA, 10 mol % AA, 50 mol % MXDA) had a Tg of 127 C., a Mn/Mw of 7830/20100 g/mol and a VN of 33 ml/g.

(18) Polyamide B3B:

(19) Production was effected as above for B3A.

(20) The polymer (30 mol % ICA, 20 mol % AA, 50 mol % MXDA) had a Tg of 114 C., a Mn/Mw of 9550/25600 g/mol and a VN of 42 ml/g.

(21) Polyamide B4A:

(22) Production was effected as above for B3A but with terephthalic acid (TPA) instead of adipic acid as additional monomer B1.

(23) The polymer (40 mol % ICA, 10 mol % TPA, 50 mol % MXDA) had a Tg of 126 C., a Mn/Mw of 5490/20900 g/mol and a VN of 32 ml/g.

(24) Polyamide B5A:

(25) Production was effected as above for B3A but with hexamethylenediamine (HMD) instead of adipic acid as additional monomer B2.

(26) The polymer (50 mol % ICA, 25 mol % HMD, 25 mol % MXDA) had a Tg of 109 C., a Mn/Mw of 8950/29900 g/mol and a VN of 52 ml/g.

(27) Polyamide B6A:

(28) A 250 ml round-necked flask was charged with 52 g (0.4 mol) of itaconic acid (ICA), 50 g of deionized water and 74 g (0.41 mol) of 2,5-bis(aminomethyl)furan (BAMF) as 70% strength aqueous solution. The reaction mixture was held at 108 C. under reflux for 60 min. The temperature was increased stepwise to 200 C. over one hour to distill-off water and the pressure was then reduced stepwise to 3 mbar to carry out the polycondensation under these conditions over a total of 75 minutes.

(29) The polymer (50 mol % ICA, 50 mol % BAMF) had a Tg of 127 C.,

(30) an Mn/Mw of 6200/72000 g/mol and a VN of 14 ml/g.

(31) Component C1:

(32) 40% strength concentrate of red phosphorus having an average particle size (d.sub.50) of 10 to 30 m in polyamide 6 (obtainable from Italmatch Chemicals Group).

(33) Component C2A:

(34) Aluminum diethylphosphinate (ExolitOP1230 from Clariant GmbH), particle size (d.sub.90)=80 m

(35) Component C2B:

(36) Aluminum diethylphosphinate (ExolitOP935 from Clariant GmbH): particle size (d.sub.90)=5.613 m

(37) determined with a Mastersizer 2000 (measuring range 0.02-20 000 m) in water.

(38) Component C3:

(39) Melamine cyanurate (MelapurMC 50 from BASF SE)

(40) Component C4:

(41) Aluminum hypophosphite (obtainable from Italmatch Chemicals Group)

(42) Component C5:

(43) Melamine polyphosphate (Melapur M200 from BASF SE)

(44) Component D1:

(45) Chopped glass fibers having an average diameter of 10 m

(46) Component D2:

(47) Sigrafil C30 0/90 biaxial carbon fiber fabric having a basis weight of 408 g/m.sup.2 obtainable from SGL Kmpers GmbH & Co. KG.

(48) Component D3:

(49) Talc (CAS-No. 14807-96-6) having an average particle size (d50) of 1.7 m determined with a Sedigraph 51XX instrument (Micromeritics Instrument Corporation) marketed under the brand name Microtalc IT extra by MONDO MINERALS B.V. (Netherlands).

(50) Production of the Molding Compositions

(51) Production of the molding compositions was effected on three extruders as described hereinbelow. The respective examples indicate the equipment used.

(52) The DSM Xplore 15 microcompounder was operated at a temperature of 260-280 C. The rotational speed of the twin screws was 60 rpm. The residence time of the polymers after feeding of the extruder was about 3 min. The microcompounder indicates the screw force required to achieve the prescribed rotational speed.

(53) To produce molded articles from compositions produced on the DSM Xplore 15 microcompounder the polymer melt was transferred by means of a heated melt vessel into the 10 cc Xplore micro-injection molding machine and immediately injected into the mold. A mold temperature of 60 C. was used. Injection molding was effected in three stages; 16 bar for 5 s, 16 bar for 5 s and 16 bar for 4 s.

(54) Further molding compositions were produced by means of a ZE25A UTXi twin-screw extruder (KraussMaffei Berstorff GmbH, Germany). The temperature profile was increased from 40 C. in zone 1, to 260 C. (zone 2), to 280 C. (zones 3-11) and kept constant. A rotational speed of 250 rpm was established, resulting in a throughput of about 15 kg/h. The extrudate was pulled through a water bath and pelletized.

(55) Further molding compositions were processed by means of a Haake Rheomex CTW 100 OS twin-screw extruder (Thermo Fisher Scientific Inc.). Zones 1 to 3 of the extruder were kept at 280 C. and a die temperature of 270 C. was employed. The extruder was operated at a rotational speed of 100 RPM, resulting in throughputs of 1.5 kg/h. The torque required to achieve the rotational speed was recorded during the process. The extrudate was pulled through a water bath and pelletized.

(56) Production of molded articles from pelletized extrudate was effected on Arburg Allrounder 470H and Arburg Allrounder 420C injection molding machines (ARBURG GmbH+Co KG) employing a melt temperature of 270 C. to 290 C., a screw speed of 100 RPM, injection pressures of 500 bar to 1100 bar, holding pressures of 500 bar to 1000 bar, a back pressure of 50 bar and a mold temperature of 80 C.

(57) Production of Carbon-Fiber-Reinforced Molding Compositions

(58) After storage under liquid nitrogen for 3 min, pelletized extrudates were comminuted by means of a ZM200 ultracentrifugation mill (Retsch) with a 1.5 mm screen pack to afford a fine powder. The powder was stored in a drying cabinet for 15 h at 60 C. and 30 mbar to remove moisture from the material. The dry powder was applied in uniform layers in the mold between and on the carbon fiber plies by means of a screen having a 0.5 mm mesh size. The amount of polymer was chosen such that with two carbon fiber plies a material thickness of 1.00.1 mm was achieved after pressing. 20.5 g to 21.5 g of pelletized material with two carbon fiber plies having a weight of 22 g to 23 g were employed. The layed-up material was placed into a press frame having internal dimensions of 16 cm16 cm and a thickness of 0.95 mm and pressed with a Collin P200 P laboratory press from Dr. Collin GmbH. The pressing conditions were as follows: 300 C. and 10 bar for 2 min, 300 C. and 100 bar for 5 min, cooling at 100 bar to 25 C. over a period of 15 min. Cutting to size of test specimens for material testing was effected by means of a Datron CNC milling maschine (ML Cube oder M35) from the inner region of the obtained sheet.

(59) The following measurements were carried out:

(60) DSC:

(61) The glass transition temperature (Tg) of the polymer was measured using a TA Instruments Q2000 differential scanning calorimeter (DSC). The cooling and heating rate was 20 K/min, the starting weight was about 8.5 mg and the purge gas was helium. Evaluation of the measured curves (second heating curve) was effected as per ISO standard 11357.

(62) GPC:

(63) The molecular weight Mn/Mw of the polyamides was determined as follows:

(64) 15 mg of the semiaromatic polyamides were dissolved in 10 ml of hexafluoroisopropanol (HFIP). 125 l respectively of these solutions were analyzed by means of gel permeation chromatography (GPC). The measurements were carried out at room temperature. Elution was effected using HFIP+0.05 wt % of potassium trifluoroacetate salt. The elution rate was 0.5 ml/min. The following column combination was employed (all columns produced by Showa Denko Ltd., Japan): Shodex HFIP-800P (diameter 8 mm, length 5 cm), Shodex HFIP-803 (diameter 8 mm, length 30 cm), Shodex HFIP-803 (diameter 8 mm, length 30 cm). The semiaromatic polyamides were detected by means of an RI detector (differential refractometry). Calibration was effected with narrowly distributed polymethyl methacrylate standards having molecular weights of M.sub.n=505 g/mol to M.sub.n=2 740 000 g/mol.

(65) The flame resistance of the molding compositions was determined according to the method UL94-V (Underwriters Laboratories Inc. Standard of Safety, Test for Flammability of Plastic Materials for Parts in 30 Devices and Appliances, p. 14 to p. 18 Northbrook 1998). Unless otherwise stated, five test pieces respectively were tested according to the procedure prescribed for the UL94V test after conditioning at room temperature and 5010% relative humidity. The sum of the afterflame times for the 5 samples after first and second flame application was reported as the total burn time.

(66) The heat release capacity, specific heat of combustion and amount of residue after pyrolysis under nitrogen were determined with an FAA Microcombustion calorimeter (from Fire Testing Technology, UK) for samples of 2.5 mg to 3.5 mg in weight, a heating rate of 1 C./s being employed and the pyrolysis oven being heated to 800 C. The afterburner was set to a temperature of 900 C. Measurement was carried out according to the procedure in ASTM D7309-13. The amount of residue was determined immediately after removal of the crucible from the instrument with a high-precision balance.

(67) The gloss values were determined with a PCE GM-60 glossmeter from PCE Deutschland GmbH. The reported gloss values are measured relative to a blackened glass sheet having a gloss value of 90 at an angle of 60 and of 84 at an angle of 20.

(68) The constitutions of the molding compositions and the results of the measurements may be found in the tables.

(69) Table 1-1 shows that, at a low concentration of flame retardants, a flame retardant effect can be achieved only by admixing the pyrrolidone-containing polyamide B1A to PA66. The force required by the extruder to maintain the rotational speed is markedly lower for the molding compositions according to the invention which is indicative of higher flowability of the molding compositions and lower stress on the equipment. Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder and the Xplore micro-injection molding machine.

(70) TABLE-US-00002 TABLE 1-1 constitutions and material properties 1 comp. 1 2 comp. 2 A1 69.25 92.0 69.0 92.0 B1A 22.75 0 23.0 0 C1 8.0 8.0 0 0 C2A 0 0 8.0 8.0 UL94 1.6 mm V-1 V-2* V-0 V-2 total burn time 38 37 42 screw force (N) 1388 2468 1035 2080 *measurement aborted after two test pieces exhibited burning drips.

(71) Table 1-2 shows that, at a low concentration of flame retardants, a flame retardant effect can be achieved only by admixing the pyrrolidone-containing polyamide B1A to PA6. The force required by the extruder to maintain the rotational speed is markedly lower for the molding composition according to the invention which is indicative of higher flowability of the molding compositions and lower stress on the equipment. Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder and the Xplore micro-injection molding machine.

(72) TABLE-US-00003 TABLE 1-2 constitutions and material properties 3 comp. 3 (% w/w) (% w/w) A2 42.75 57.0 B1A 14.25 0 D1 25.0 25.0 C2A 0 0 C4 12.0 12.0 C3 6.0 6.0 UL94 1.6 mm V-0 V-2 classification total burn time 20 85 for 5 samples (s) screw force (N) 1686 3720

(73) As is shown in table 1-3, compared to commercially available amorphous polyamides, admixing pyrrolidone-containing polyamides achieves a markedly higher surface quality which is both visually readily apparent and demonstrated by markedly higher gloss values (table 1-3).

(74) Selar 3246 from DuPont is an amorphous polyamide produced by reaction of isophthalic acid and terephthalic acid with hexamethylenediamine. The employed product had a constitution of 19 g/100 g terephthalic acid, 46 g/100 g isophthalic acid and 35 g/100 g hexamethylenediamine. The employed product had a viscosity number of 79 ml/g, determined in a 0.5 wt % solution in 96 wt % sulfuric acid at 25 C. as per ISO 307.

(75) Production of the molding compositions and test specimens was effected with the ZE25A UTXi twin-screw extruder.

(76) TABLE-US-00004 TABLE 1-3 constitutions and material properties 4 comp. 4 A1 39.0 39.45 A2 4.8 4.8 B1A 7.2 0 Selar 3426 0 6.75 D1 30.0 30.0 C2A 16.0 16.0 C5 3.0 3.0 UL94 0.8 mm V-0 V-0 gloss value 43.3 21.4

(77) As is demonstrated in table 1-4, mixing commercially available polyamides with pyrrolidone-containing polyamides achieves molding compositions having a lower potential for heat release and higher pyrolysis residues. Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder and the Xplore micro-injection molding machine.

(78) TABLE-US-00005 TABLE 1-4 constitutions and material properties comp. 5 5 (% w/w) (% w/w) A1 100 80 B1A 0 20 specific heat of combustion (kJ g.sup.1) 28.1 26.7 % change compared to comp. 5 5 heat release capacity (J g.sup.1 K.sup.1) 610 570 % change compared to comp. 5 6 residue after pyrolysis 0.2 12.2 % change compared to comp. 5 +610

(79) Even when using further aromatic carboxylic acids (table 2) and also aliphatic dicarboxylic acids (table 3) in the synthesis of the pyrrolidone-containing polyamides the mixtures thereof with commercially available polyamides can achieve a markedly improved flame resistance even with a low concentration of flame retardants. Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder and the Xplore micro-injection molding machine.

(80) TABLE-US-00006 TABLE 2 constitutions and material properties 1 comp. 1 2 comp. 2 (% w/w) (% w/w) (% w/w) (% w/w) A1 50.5 67.0 50.25 67.0 B2A 16.5 0 16.75 0 D1 25.0 25.0 25.0 25.0 C1 8.0 8.0 0 0 C2A 0 0 8.0 8.0 UL94 1.6 mm V-0 V- V-1 V- total burn time 17 49 for 5 samples (s) reason for failure burn time > burn time > 30 s 30 s

(81) TABLE-US-00007 TABLE 3 constitutions and material properties 1 2 (% w/w) (% w/w) A1 50.5 50.5 B3A 16.5 0 B3B 0 16.5 D1 25.0 25.0 C1 8.0 8.0 UL94 1.6 mm V-1 V-1 classification total burn time 45 93 for 5 samples (s)

(82) When, using a relatively small amount of flame retardant, the flammability of the inventive mixture of PA 66 with the pyrrolidone-containing polyamide B3A is compared with a commercially available, amorphous and semiaromatic polyamide, a markedly better rating is achieved as is shown in table 3-2. Processing can moreover be effected with a markedly lower level of stress on the extruder. The extrudate obtained in accordance with the invention had a markedly smoother surface. Production of the molding compositions was effected with the Haake Polylab extruder.

(83) TABLE-US-00008 TABLE 3-2 constitutions and material properties 3 comp. 3 % w/w % w/w A/1 70.0 87.5 B3A 17.5 0 Selar 3426 0 17.5 C2B 12.5 12.5 extrudate surface qualities smooth surface rough surface UL94 0.8 mm V-2 V- (storage at RT, 50% RH) UL94 0.8 mm V-0 V- (storage at 70 C. for 168 h) reason for failure afterburn times > 30 s holder burning extruder torque (Nm) 8 11

(84) Even when using further aromatic carboxylic acids in the synthesis of pyrrolidone-containing polyamides the mixtures thereof with commercially available polyamides achieve a markedly improved flame resistance even at a low concentration of flame retardants (see table 4-1 and table 4-2). In particular, molding compounds comprising pyrrolidone-containing polyamides can be produced with a markedly lower extruder torque which results in a lower level of stress on, and improved lifetime of, the extruder.

(85) Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder and the Xplore micro-injection molding machine.

(86) TABLE-US-00009 TABLE 4-1 constitutions and material properties 1 2 comp. 2 (% w/w) (% w/w) (% w/w) A1 50.5 50.25 67.0 B4A 16.5 16.75 0 D1 25.0 25.0 25.0 C1 8.0 0 0 C2A 0 8.0 8.0 UL94 1.6 mm classification V-0 V-1 V- total burn burn time 30 59 for 5 samples (s) reason for failure burn time > 30 s 998 990 2310

(87) TABLE-US-00010 TABLE 4-2 constitutions and material properties. Comparative example in table 1-2 3 (% w/w) A/2 42.75 B4A 14.25 D1 25.0 C4 12.0 C3 6.0 UL94 1.6 mm classification V-0 total burn time 20 for 5 samples (s) extruder screw force (N) 2574

(88) When, using a relatively small amount of flame retardant, the flammability of the inventive mixture of PA 66 with the pyrrolidone-containing polyamide B4A is compared with a commercially available, amorphous and semiaromatic polyamide, a markedly better rating is achieved as is shown in table 4-3. Processing can moreover be effected with a markedly lower level of stress on the extruder. Production of the molding compositions was effected with the Haake Polylab extruder.

(89) TABLE-US-00011 TABLE 4-3 constitutions and material properties 4 comp. 4 % w/w % w/w A1 70.0 70.0 B4A 17.5 0 Selar 3426 0 17.5 C2B 12.5 12.5 UL94 0.8 mm (storage V-2 V- at RT, 50% RH) UL94 0.8 mm (storage V-0 V- at 70 C. for 168 h) reason for failure burn time > 30 s holder burning extruder torque (Nm) 8 11

(90) The pelletized materials of the molding compositions specified in table 4-3 were additionally used to press carbon fiber composite sheets of 1 mm in thickness according to the abovedescribed process. Test specimens milled from these composite sheets likewise exhibited markedly better flame resistance after production in accordance with the invention (see table 4-4).

(91) TABLE-US-00012 TABLE 4-4 constitution and fire properties of carbon fiber composite sheets. 5 comp. 5 % w/w % w/w A1 34.0 34.0 B3A 8.5 0 Selar 3426 0 8.5 C2B 6.1 6.1 carbon fiber 51.4 51.4 UL94 1.0 mm V-1 V- reason for for failure burn time > 30 s

(92) Even when using further diamines in the synthesis of pyrrolidone-containing polyamides the mixtures thereof with commercially available polyamides achieve a markedly improved flame resistance even at a low concentration of flame retardants (see table 5). Compared to exclusive use of component A, addition of the pyrrolidone-containing polyamide achieves increased residues after pyrolysis and also markedly reduced values for specific heat of combustion and heat release capacity. Processing of a molding composition according to the invention can be effected with a markedly lower level of stress on the extruder.

(93) Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder and the Xplore micro-injection molding machine.

(94) TABLE-US-00013 TABLE 5 1 comp. 1 (% w/w) (% w/w) A2 42.75 57.0 B5A 14.25 0 D1 25.0 25.0 C4 12.0 12.0 C3 6.0 6.0 UL94 1.6 mm classification V-0 V-2 total burn time 17 85 for 5 samples (s) extruder screw force (N) 2936 3720 residue after pyrolysis (% w/w) 14.4 13.1 (excluding glass fiber) % change compared to comp. 1 +10 specific heat of combustion (kJ g.sup.1) 14.5 16.0 % change compared to comp. 1 9 heat release capacity (J g.sup.1 K.sup.1) 213 236 % change compared to comp. 1 6

(95) As is shown in table 6, adding the pyrrolidone-containing polyamide obtained from 2,5-furandicarboxylic acid to PA6 when using a relatively small amount of flame retardant achieves a markedly better flame resistance. Compared to exclusive use of component A, addition of the pyrrolidone-containing polyamide achieves markedly increased residues after pyrolysis and also markedly reduced values for specific heat of combustion and heat release capacity. Processing of the molding composition according to the invention can be effected with a markedly lower level of stress on the extruder.

(96) Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder and the Xplore micro-injection molding machine.

(97) TABLE-US-00014 TABLE 6 1 comp. 1 2 comp. 2 (% w/w) (% w/w) (% w/w) (% w/w) A2 50.25 67.0 42.75 57.0 B6A 16.75 0 14.25 0 D1 25.0 25.0 25.0 25.0 C2A 8.0 8.0 0 0 C4 0 0 12.0 12.0 C3 0 0 6.0 6.0 UL94 1.6 mm classification V-1 V-2 V-0 V-2 total burn time 73 131 25 85 for 5 samples (s) extruder screw force (N) 2530 3720 residue after pyrolysis (% w/w) 19.4 13.1 (excluding glass fiber) % change compared to comp. 2 +48 specific heat of combustion (kJ g.sup.1) 13.6 16.0 % change compared to comp. 2 15 heat release capacity (J g.sup.1 K.sup.1) 210 236 % change compared to comp. 2 11

(98) As is shown in table 7, adding pyrrolidone-containing polymers to PA6 markedly reduces the stress on the extruder when processing fillers.

(99) Production of the molding compositions and test specimens was effected with the DSM Xplore 15 microcompounder.

(100) TABLE-US-00015 TABLE 7 1 2 3 4 5 6 comp. 1 A2 63 56 63 56 63 56 70 B1A 7 14 0 0 0 0 0 B3A 0 0 7 14 0 0 0 B5A 0 0 0 0 7 14 0 D3 30 30 30 30 30 30 30 extruder screw 1920 1440 2810 2100 2680 2180 3250 force (N)