THERMOPLASTIC POLYAMIDE MOLDING COMPOSITIONS THAT RESIST HEAT

Abstract

Disclosed herein is a thermoplastic molding composition which includes A) from 10 to 99.9% by weight of a thermoplastic polyamide, B) from 0.1 to 20% by weight of at least one hyperbranched polyester having an acid number in the range of from 10 to 700 mg KOH/g and a hydroxyl number in the range of from 0 to 550 mg KOH/g, C) from 0 to 50% by weight of fibrous or particulate fillers, and D) from 0 to 45% by weight of further additives, where the total of the percentages by weight of components A) to D) is 100% by weight.

Claims

1. A thermoplastic molding composition, comprising A) from 10 to 99.9% by weight of a thermoplastic polyamide, B) from 0.1 to 20% by weight of at least one hyperbranched polyester having an acid number according to DIN 53402 in the range of from 10 to 700 mg KOH/g and a hydroxyl number according to DIN 53240 in the range of from 0 to 550 mg KOH/g, C) from 0 to 50% by weight of fibrous or particulate fillers, and D) from 0 to 45% by weight of further additives, wherein the total of the percentages by weight of components A) to D) is 100% by weight, wherein the hyperbranched polyester is obtainable by reacting a) one or more dicarboxylic acid(s) or one or more derivative(s) thereof with one or more at least three functional alcohols, or b) one or more tricarboxylic acid(s) or higher polycarboxylic acids, or one or more derivative(s) thereof with one or more diol(s), wherein the carboxylic acids are selected from the group consisting of adipic acid, citric acid, L-aspartic acid, maleic anhydride, and 1,2-cyclohexanedicarboxylic acid anhydride, and the alcohols are selected from the group consisting of pentaerythritol, trimethylolpropane, and neopentyl glycol.

2. The thermoplastic molding composition according to claim 1, comprising from 1 to 50% by weight of a fibrous or particulate additive C).

3. The thermoplastic molding composition according to claim 1, in which the thermoplastic polyamide A) is selected from the group consisting of aliphatic or semiaromatic polyamides.

4. The thermoplastic molding composition according to claim 1, wherein the at least one hyperbranched polyester has an acid number according to DIN 53402 in the range of from 20 to 550 mg KOH/g and a hydroxyl number according to DIN 53240 of 0 mg KOH/g or in the range of from 100 to 450 mg KOH/g.

5. The thermoplastic molding composition according to claim 1, wherein the at least one hyperbranched polyester has a number average molecular weight M.sub.n, determined by gel permeation chromatography in dimethyl acetamide and calibration against PMMA; detection system: refractive index, in the range of from 350 to 20000 g/mol.

6. A method of using at least one hyperbranched polyester as defined in claim 1 as a heat stabilizer in thermoplastic polyamide molding compositions.

7. A method of using the thermoplastic molding composition according to claim 1 for producing fibers, foils, and moldings of any type.

8. A fiber, foil, or molding, made of the thermoplastic molding composition according to claim 1.

9-12. (canceled)

13. The thermoplastic molding composition according to claim 1, in which the thermoplastic polyamide A) is selected from the group consisting of PA 6, PA 66, PA 6/66, PA 66/6, PA 6/6.36, PA 6I/6T, PA 6T/6I, PA 9T and PA 6T/66.

Description

EXAMPLES

I. Synthesis of Hyperbranched Polyesters Used as Heat Stabilizers in Polyamide 6

Example 1

[0332] Hyperbranched Polyester

[0333] Polyester using pentaerythritol and adipic acid in molar ratio 0.7:1

[0334] 476.53 g pentaerythritol (3.5 mol), 730.7 g adipic acid (5.0 mol) and 0.6 g titanium(IV) butoxide (0.0018 mol) were added to a 2 L reaction vessel equipped with N.sub.2 inlet, thermometer, stirrer and distillation column. The reaction mixture was slowly heated with the help of an oil bath up to a temperature of 160° C. (oil temperature) under Nitrogen atmosphere. After the complete homogenization of the components, the reaction mixture was kept at 160° C. for 2 hours 45 minutes while water was collected as distillate (80 g). The resulting material (1090 g) was collected and characterized:

[0335] Acid number: 201 mg KOH/g according to DIN 53402

[0336] Hydroxyl number: 382 mg KOH/g according to DIN 53240 part 2

[0337] Gel permeation chromatography in dimethylacetamide (DMAc): M.sub.n: 1780 g/mol, M.sub.w: 4560 g/mol (calibration against PMMA, detection system: refractive index)

[0338] Dispersity: 2.56

Example 2

[0339] Hyperbranched Polyester

[0340] Polyester using citric acid monohydrate, trimethylolpropane, L-aspartic acid in molar ratio 2:0.7:0.3

[0341] 693.50 g citric acid monohydrate (3.3 mol), 154.97 g trimethylolpropane (1.16 mol) and 65.88 g of aspartic acid were added to a 2 L reaction vessel equipped with N.sub.2 inlet, thermometer, stirrer and distillation column. The reaction mixture was slowly heated with the help of an oil bath up to a temperature of 130° C. (oil temperature) under nitrogen atmosphere. After the complete homogenization of the components, the reaction mixture was kept at 130 C for 10 hours minutes, under stirring, while water was collected as distillate (91 g). The resulting material (709 g) was collected and characterized:

[0342] Acid number: 466 mg KOH/g according to DIN 53402

[0343] Hydroxyl number: 215 mg KOH/g according to DIN 53240 part 2

[0344] Gel permeation chromatography in tetrahydrofurane: M.sub.n: 501 g/mol, M.sub.w: 2540 g/mol

[0345] (calibration against PMMA, detection system: refractive index)

[0346] Dispersity: 5.06

Example 3

[0347] Hyperbranched Polyester

[0348] Polyester using pentaerythritol and adipic acid in molar ratio 0.7:1

[0349] 476.53 g pentaerythritol (3.5 mol), 730.7 g adipic acid (5.0 mol) and 0.6 g titanium(IV) butoxide (0.0018 mol) were added to a 2 L reaction vessel equipped with N.sub.2 inlet, thermometer, stirrer and distillation column. The reaction mixture was slowly heated with the help of an oil bath up to a temperature of 160° C. (oil temperature) under nitrogen atmosphere. After the complete homogenization of the components, the reaction mixture was kept at 130° C. for four hours, under stirring, while water was collected as distillate (63 g). The resulting material (1000 g) was collected and characterized:

[0350] Acid number: 212 mg KOH/g according to DIN 53402

[0351] Hydroxyl number: 392 mg KOH/g according to DIN 53240 part 2

[0352] Gel permeation chromatography in DMAc: M.sub.n: 1710 g/mol, M.sub.w: 3750 g/mol

[0353] (calibration against PMMA, detection system: refractive index) Dispersity: 2.19

Example 4

[0354] Hyperbranched Polyester

[0355] Polyester using pentaerythritol and maleic anhydride in molar ratio 0.7:1

[0356] 142.96 g pentaerythritol (1.05 mol), 147.09 g maleic anhydride (1.5 mol) were added to a 500 mL reaction vessel equipped with N.sub.2 inlet, thermometer, stirrer and distillation column. The reaction mixture was slowly heated with the help of an oil bath up to a temperature of 140° C. (oil temperature) under nitrogen atmosphere. After the complete homogenization of the components, the reaction mixture was kept at 140° C. for 30 minutes, under stirring. Traces of water as condensate were collected. The resulting material (250 g) was collected and characterized:

[0357] Acid number: 176 mg KOH/g according to DIN 53402

[0358] Hydroxyl number: 230 mg KOH/g according to DIN 53240 part 2

[0359] Gel permeation chromatography in DMAc: M.sub.n: 2410 g/mol, M.sub.w: 30300 g/mol

[0360] (calibration against PMMA, detection system: refractive index)

[0361] Dispersity: 12.58

Example 5

[0362] Hyperbranched Polyester

[0363] Polyester using cyclohexane-1,2-dicarboxylic acid anhydride and trimethylolpropane in molar ratio 1:1

[0364] 1176.3 g cyclohexane-1,2-dicarboxylic acid anhydride (7.63 mol), 1023.7 g trimethylolpropane (7.63 mol) were added to a 4 L reaction vessel equipped with N.sub.2 inlet, thermometer, stirrer and distillation column. The reaction mixture was slowly heated with the help of an oil bath up to a temperature of 160° C. (oil temperature) under nitrogen atmosphere. After the complete homogenization of the components, the reaction mixture was kept at 160° C. for 45 minutes, under stirring. Then the temperature was increased to 180° C. and the reaction mixture was kept under stirring for 4 hours while water was condensed out (59 g). The resulting material (2 Kg) was collected and characterized:

[0365] Acid number: 83 mg KOH/g according to DIN 53402

[0366] Hydroxyl number: 257 mgKOH/g according to DIN 53240 part 2

[0367] Gel permeation chromatography in THF: M.sub.n: 840 g/mol, M.sub.w: 1450 g/mol

[0368] (calibration against PMMA, detection system: refractive index)

[0369] Dispersity: 1.78

[0370] Tg: 17.3

Example 6

[0371] Hyperbranched Polyester

[0372] Polyester using cyclohexane-1,2-dicarboxylic acid anhydride and trimethylolpropane in molar ratio 1.2:1

[0373] 1480 g cyclohexane-1,2-dicarboxylic acid anhydride (9.6 mol), 1073.4 g trimethylolpropane (8 mol) were added to a 4 L reaction vessel equipped with N.sub.2 inlet, thermometer, stirrer and distillation column.

[0374] The reaction mixture was slowly heated with the help of an oil bath up to a temperature of 160° C. (oil temperature) under nitrogen atmosphere. After the complete homogenization of the components, the reaction mixture was kept at 160° C. for 45 minutes, under stirring. Then the temperature was increased to 180° C. and the reaction mixture was kept under stirring for 4.75 hours while water was condensed out (73 g). The resulting material (2.3 Kg) was collected and characterized:

[0375] Acid number: 93 mg KOH/g according to DIN 53402

[0376] Hydroxyl number: 194 mg KOH/g according to DIN 53240 part 2

[0377] Gel permeation Chromatography in THF: M.sub.n: 1110 g/mol, M.sub.w: 2560 g/mol

[0378] (calibration against PMMA, detection system: refractive index)

[0379] Dispersity: 2.31

[0380] Tg: 31.9

Example 7

[0381] Hyperbranched Polyester

[0382] Polyester using cyclohexane-1,2-dicarboxylic acid anhydride, neopentyl glycol and trimethylolpropane in molar ratio 1:0.5:0.5

[0383] 1387.8 g cyclohexane-1,2-dicarboxylic acid anhydride (9 mol), 603.8 g trimethylolpropane (4.5 mol) and 468.7 g neopentyl glycol (4.5 mol) were added to a 4 L reaction vessel equipped with N.sub.2 inlet, thermometer, stirrer and distillation column. The reaction mixture was slowly heated with the help of an oil bath up to a temperature of 140° C. (oil temperature) under nitrogen atmosphere. After the complete homogenization of the components, the temperature was increased to 180° C. and the reaction mixture was kept under stirring for 5 hours while water was condensed out (78 g). The resulting material (2.27 Kg) was collected and characterized: Acid number: 92 mg KOH/g according to DIN 53402

[0384] Hydroxyl number: 182 mg KOH/g according to DIN 53240 part 2

[0385] Gel permeation Chromatography in THF: M.sub.n: 810 g/mol, M.sub.w: 1320 g/mol

[0386] (calibration against PMMA, detection system: refractive index)

[0387] Dispersity: 1.62

[0388] Tg: 31.9

II. Application Examples

[0389] For showing the improvement of the long-term heat aging stability of the polyamide molding materials by adding the hyperbranched polyesters, molding compositions were prepared by melt compounding. The components were mixed in a twin-screw extruder (ZSK 26 of Berstorff) at 20 kg/h and 280 to 330° C. employing a flat temperature profile. The obtained extrudates were cooled and granulated.

[0390] The test bodies for the tests shown in the following Table 1 were prepared using an injection molding machine (Arburg 420 C) at a polymer temperature of 290 to 330° C. and a tool temperature of 80 to 140° C.

[0391] The flame retardancy of the molding composition was determined according to method UL94-V (Underwriters Laboratories Inc. Standard of Safety, “Test for Flammability of Plastic Materials for Parts in Devices and Appliances”, pages 14 to 18, Northbrook 1998).

[0392] The glow-wire resistance was determined as the Glow-Wire Flammability Index (GWFI) according to IEC 60695-2-12 as of 2019.

[0393] GWFI test was carried out employing 3 test bodies (for example 60×60×1.0 mm plates or round discs) for which with the help of a glow-wire at temperatures between 550 and 960° C., the maximum temperature was determined, which in 3 subsequent tests did not lead to an inflammation after treating with the glow-wire. The test body was pressed for 30 seconds with a power of 1 N against the heated glow-wire. The intrusion depth of the glow wire was restricted to 7 mm. The test was passed when the test body, after removing the glow-wire burned for less than 30 seconds and if a silk paper lying under the test body is not inflamed.

[0394] In the test, the following components were employed:

[0395] Hereinafter, components A correspond to above component A, components Ex correspond to above component B, components B correspond to above component C, and components C to E correspond to above component D of the molding composition of the invention.

[0396] Component A/1:

[0397] Polyamide 66 having a viscosity number of 150 mL/g, determined as 0.5 wt % solution in 96 wt % sulfuric acid at 25° C. according to ISO 307 (Ultramid®A27 of BASF SE)

[0398] Component A/2:

[0399] Polyamide 66 having a viscosity number of 125 mL/g, determined as 0.5 wt % solution in 96 wt % sulfuric acid at 25° C. according to ISO 307 (Ultramid® A24 of BASF SE)

[0400] Component A/3:

[0401] Polyamide 6 having a viscosity number of 125 mL/g, determined as 0.5 wt % solution in 96 wt % sulfuric acid at 25° C. according to ISO 307 (Ultramid® B24 of BASF SE).

[0402] Component A/4:

[0403] Polyamide 6 having a viscosity number of 105 mL/g, determined as 0.5 wt % solution in 96 wt % sulfuric acid at 25° C. according to ISO 307 (Ultramid® B22 of BASF SE)

[0404] Component A/5:

[0405] Polyamide 6 having a viscosity number of 100 mL/g, determined as 0.5 wt % solution in 96 wt % sulfuric acid at 25° C. according to ISO 307 (Genestar® GC61010 of Kuraray Europe GmbH)

[0406] Component B:

[0407] Commercially available glass fibers for polyamides having a length of 4.5 mm and diameter of 10 μm

[0408] Component C/1:

[0409] Melamine cyanurate having an average particle size of 2.6 μm (Melapur® MC 25 of BASF SE)

[0410] Component C/2:

[0411] Halogen-free flame-retardant mixture based on di-alkyl-phosphinates (Exolit® OP1400 of Claiant Plastics & Coatings (Deutschland) GmbH)

[0412] Component C/3:

[0413] Commercially available zinc stannate (Flamtard® S of William Blythe Ltd.)

[0414] Component D/1:

[0415] Phenolic antioxidans 3,3′-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-N,N′-hexamethylenedipropionamide (CAS: 23128-74-7 of BASF SE)

[0416] Component D/2:

[0417] Commercially available heat stabilizer based on Cu(I) iodide (CAS: 7681-65-4)

[0418] Component D/3:

[0419] Commercially available heat stabilizer based on KI (CAS: 7681-11-0)

[0420] The molar ratio of component D/2: component D/3 is 1:4.

[0421] Component E/1:

[0422] Commercially available processing aid based on glycerol and fatty acids (LOXIOL® P 1206 of Emery Oleochemicals GmbH)

[0423] Component E/2:

[0424] Commercially available aluminium stearate (CAS: 300-92-5)

[0425] Component E/3:

[0426] Commercially available ethylene-bis-stearamide (CAS: 110-30-5)

[0427] Component Ex1 to Ex7:

[0428] Hyperbranched polyesters of Examples 1 to 7 as indicated above

[0429] The total weight of all ingredients of components A to Ex in Table 1 sum up to 100 wt %. The compositions and properties of the compositions are shown in Table 1 below.

TABLE-US-00003 TABLE 1 Component E1 V1 E2 E3 E4 E5 E6 A/1 79.1 80 A/2 37.95 A/3 10 10 A/4 8 A/5 47.9 47.9 47.9 47.9 B 30 30 30 30 30 C/1 9 9 C/2 22.5 20 20 20 20 C/3 0.15 0.15 0.15 0.15 D/1 0.5 0.5 0.35 0.35 0.35 0.35 0.35 D/2 + D/3 0.1 E/1 0.4 0.4 E/2 0.2 E/3 0.6 0.6 0.6 0.6 Ex1 1 1 Ex3 1 Ex5 1 Ex7 1 Ex7 1 Test method E1 V1 E2 E3 E4 E5 E6 Viscosity number [cm.sup.3/g] 147 160 116 82 89 86 87 Modulus of elasticity (ISO 527) [MPa] 3590 3620 11790 10260 10460 10470 10250 Tensile strength (ISO 527) [MPa] 75,1 76 156 146 136 130 136 Elongation at break (ISO 527) [%] 5.1 4.4 2.6 2.2 2.1 2.0 2.2 Impact strength (ISO 179/1eU) [kJ/m.sup.2] 50 54.9 65 50 51 45 53 Notched impact strength 2.9 2.9 8.5 7.9 8.2 7.8 8.3 (ISO 179/1eA) [kJ/m.sup.2] MVR 275° C./5 Kg (ISO1133) 195 81 29 MVR 325° C./5 Kg (ISO1133) 94 114 133 116 UL94-V test (0.4 mm) n.a. V-0 V-0 V-0 n.a. V-0 V-0 GWFI 960° C./0.75 mm passed passed passed passed passed passed passed Relative tensile strength after heat 100 100 100 100 100 100 100 aging (180° C. after 0 h) [%] Relative tensile strength after 69 95 83 84 84 86 81 heat aging (180° C. after 150 h) [%] Relative tensile strength after heat 78 65 83 78 78 78 76 aging (180° C. after 300 h) [%] Relative tensile strength after heat 77 65 79 76 73 76 74 aging (180° C. after 500 h) [%] Relative tensile strength after heat 89 61 73 69 66 69 66 aging (180° C. after 1000 h) [%] Relative tensile strength after heat 81 55 66 58 59 64 58 aging (180° C. after 2000 h) [%]

[0430] The data of Table 1 show that the molding compositions containing a hyperbranched polyester as additional heat stabilizer show a significantly improved long-term heat aging stability compared to ordinary stabilizers on copper basis. The mechanical properties after heat aging at 180° C. are especially improved.

III. Application Examples for Molding Compositions Containing Nigrosine

[0431] Component A:

[0432] Polyamide 6 having a viscosity number VZ of 150 ml/g, determined as 0.5 wt % solution in 96% sulfuric acid by 25° C. according to ISO 307 (Ultramid® B27 of BASF SE)

[0433] Component B:

[0434] Commercially available glass fibers for polyamides having a length of 4.5 mm and diameter of 10 μm

[0435] Component D/2:

[0436] Commercially available heat stabilizer based on Cu(I) iodide (CAS: 7681-65-4)

[0437] Component D/3:

[0438] Commercially available heat stabilizer based on KI (CAS: 7681-11-0)

[0439] Component D/4:

[0440] Phenolic antioxidans 3,3′-bis(3,5-di-tert-butyl-4-hydroxyphenyl)-N,N′-hexamethylenedipropionamide (CAS: 23128-74-7 of BASF SE)

[0441] Component E/3:

[0442] Ethylene bis stearamide of Lonza Cologne GmbH (CAS: 110-30-5)

[0443] Component E/4:

[0444] Nigrosine, solvent black 7 (CAS: 8005-02-5)

[0445] Component E/5:

[0446] Carbon black, Printex® 60 of Orion Engineered Carbons GmbH

[0447] Component Ex1:

[0448] Hyperbranched polyester of Example 1.

[0449] The compositions and their properties are shown in the following Table 2.

TABLE-US-00004 TABLE 2 Component V1 E1 E2 A 69.26 68.26 68.4 B 30 30 30 D/2 0.03 D/3 0.11 D/4 0.139 E/3 0.3 0.3 0.3 E/4 0.2 0.2 0.2 E/5 0.1 0.1 0.1 Ex1 1 1 Test methods V2 E1 E2 Modulus of elasticity (ISO 527) [MPa] 9300 9440 9395 Tensile strength (ISO 527) [MPa] 167 182 177 Elongation at break (ISO 527) [%] 4.5 3.9 3.96 MVR 275° C./5 kg [cm.sup.3/10'] 28 69 73 Relative tensile strength after heat aging (150° C./3000 h) [%] 78 86 90 Relative tensile strength after heat aging (180° C./3000 h) [%] 53 79 66 Relative elongation at break after heat aging (150° C./3000 h) [%] 36 49 51 Relative elongation at break after heat aging (180° C./3000 h) [%] 21 43 34

[0450] The molding composition which is free of metal halides (E2) as well as the molding composition containing metal halides (E1) show superior properties after heat aging over significant time. Furthermore, the mechanical properties at room temperature and the flow behavior are significantly increased.