Polyamide moulding compound and moulded articles produced therefrom

Abstract

Disclosed is a polyamide moulding compound formed from a mixture of partially crystalline, aliphatic polyamides and partially crystalline, partially aromatic polyamides and also fibrous reinforcing materials. The partially crystalline, partially aromatic polyamides are thereby formed from a diamine component, a dicarboxylic acid component and possibly a lactam- and/or -amino acid component. The mixture and/or the moulding compound can include further components. Moulded articles produced from these moulding compounds are used, for example, in the automobile sphere, in the household sphere, in measuring, regulating and control technology or in mechanical engineering.

Claims

1. A polyamide moulding compound comprising: (I) 40 to 100% by weight of a mixture made of (A) 68 to 88% by weight of at least one partially crystalline, aliphatic polyamide and (B) 12 to 32% by weight of at least one partially crystalline, partially aromatic polyamide, formed from a diamine component (Ba), a dicarboxylic acid component (Bb), and optionally a lactam- and/or -amino acid component (Bc), wherein the diamine component (Ba) is present essentially in equimolar amount to the dicarboxylic acid component (Bb), the quantity of lactam- and/or -amino acid component (Bc) is 0 to 15% by mol, and the sum of components (Ba) to (Bc) is 100% by mol, wherein the diamine component (Ba) consists of (Ba1) 62 to 96 mol-parts of 1,6-hexanediamine, (Ba2) 4 to 38 mol-parts of bis(aminomethyl)cyclohexane, and (Ba3) 0 to 30 mol-parts of one or more cycloaliphatic diamines, different from (Ba2), wherein the sum of (Ba2) and (Ba3) is 4 to 38 mol-parts and the sum of (Ba1), (Ba2) and (Ba3) is 100 mol-parts, the dicarboxylic acid component (Bb) consists of (Bb1) 64 to 100 mol-parts of terephthalic acid, (Bb2) 0 to 18 mol-parts of isophthalic acid, and (Bb3) 0 to 18 mol-parts of one or more aliphatic dicarboxylic acids with 6 to 18 C atoms, wherein the sum of (Bb1), (Bb2) and (Bb3) is 100 mol-parts, and the lactam- and/or -amino acid component (Bc) consists of one or more lactams and/or -amino acids, wherein the sum of the lactams and/or -amino acids is 100 mol-parts, and the proportions of (A) and (B) are related to the sum of the polyamides (A) and (B) and constitute in total 100% by weight of the mixture, (II) 0-60% by weight of fibrous reinforcing materials; (III) 0-30% by weight of particulate fillers, different from (II) and (IV) to (VI); (IV) 0-20% by weight of impact modifiers; (V) 0-2.0% by weight of heat stabilisers; (VI) 0-6% by weight of auxiliary materials and/or additives different from (II)-(V); the sum of components (I)-(VI) constituting 100% by weight of the polyamide moulding compound.

2. The polyamide moulding compound according to claim 1, wherein the at least one partially crystalline, aliphatic polyamide (A) is selected from the group consisting of polyamide 46, polyamide 6, polyamide 56, polyamide 66, polyamide 11, polyamide 12, polyamide 1212, polyamide 1010, polyamide 1012, polyamide 1112, polyamide 610, polyamide 106, polyamide 612, polyamide 614, polyamide 616, polyamide 516, polyamide 618, polyamide 69, polyamide 810, copolyamides thereof, and mixtures, blends or alloys thereof.

3. The polyamide moulding compound according to claim 1, wherein the mixture (I) comprises (A) 68 to 85% by weight of the at least one partially crystalline, aliphatic polyamide and (B) 15 to 32% by weight of the at least one partially crystalline, partially aromatic polyamide.

4. The polyamide moulding compound according to claim 1, wherein the at least one partially crystalline, aliphatic polyamide (A) has a solution viscosity .sub.rel, measured in m-cresol (0.5 g polymer in 100 ml m-cresol, 20 C.) in the range of 1.5 to 3.0.

5. The polyamide moulding compound according to claim 1, wherein the diamine component (Ba) is selected from (Ba1) 65 to 90 mol-parts of 1,6-hexanediamine, (Ba2) 10 to 35 mol-parts of bis(aminomethyl)cyclohexane, and (Ba3) 0 to 25 mol-parts of one or more cycloaliphatic diamines, different from (Ba2), wherein the sum of (Ba2) and (Ba3) is 10 to 35 mol-parts and the sum of (Ba1), (Ba2), and (Ba3) is 100 mol-parts.

6. The polyamide moulding compound according to claim 1, wherein the diamine component (Ba) is selected from (Ba1) 70 to 82 mol-parts of 1,6-hexanediamine, (Ba2) 18 to 30 mol-parts of bis(aminomethyl)cyclohexane, and (Ba3) 0 to 12 mol-parts of one or more cycloaliphatic diamines which are different from (Ba2), wherein the sum of (Ba2) and (Ba3) is 18 to 30 mol-parts and the sum of (Ba1), (Ba2), and (Ba3) is 100 mol-parts.

7. The polyamide moulding compound according to claim 1, wherein the dicarboxylic acid component (Bb) is selected from (Bb1) 70 to 100 mol-parts of terephthalic acid, (Bb2) 0 to 15 mol-parts of isophthalic acid, and (Bb3) 0 to 15 mol-parts of one or more aliphatic dicarboxylic acids with 6 to 18 C atoms, wherein the sum of (Bb1), (Bb2), and (Bb3) is 100 mol-parts.

8. The polyamide moulding compound according to claim 1, wherein the dicarboxylic acid component (Bb) is selected from (Bb1) 80 to 100 mol-parts of terephthalic acid, (Bb2) 0 to 10 mol-parts of isophthalic acid, and (Bb3) 0 to 10 mol-parts of one or more aliphatic dicarboxylic acids with 6 to 18 C atoms, wherein the sum of the (Bb1), (Bb2), and (Bb3) is 100 mol-parts.

9. The polyamide moulding compound according to claim 1, wherein the quantity of the lactam- and/or -amino acid component (Bc) is 0 to 10% by mol.

10. The polyamide moulding compound according to claim 1, wherein the sum of the mol-parts of (Ba2) bis(aminomethyl)cyclohexane, (Ba3) cycloaliphatic diamine, (Bb2) isophthalic acid, and (Bb3) aliphatic dicarboxylic acid is at most 38 mol-parts.

11. The polyamide moulding compound according to claim 1, wherein: the diamine component (Ba) is selected from (Ba1) 65 to 85 mol-parts of 1,6-hexanediamine and (Ba2) 15 to 35 mol-parts of bis(aminomethyl)cyclohexane, and the sum of (Ba1) and (Ba2) is 100 mol-parts and/or the dicarboxylic acid component (Bb) is selected from (Bb1) 80 to 100 mol-parts of terephthalic acid and (Bb3) 0 to 20 mol-parts of one or more aliphatic dicarboxylic acids with 6 to 18 C atoms, and the sum of (Bb1) and (Bb3) being 100 mol-parts.

12. The polyamide moulding compound according to claim 1, wherein the at least one partially crystalline, partially aromatic polyamide (B) has a glass transition temperature of at least 140 C., a melting temperature of at most 340 C., a modulus of elasticity between 2,400 and 4,200 MPa, and/or a relative viscosity, measured at 20 C. and a concentration of 0.5 g/dl in m-cresol, of 1.45 to 1.95.

13. The polyamide moulding compound according to claim 1, wherein the content of the components, independently of each other, is (I) from 40 to 84.9% by weight, (II) from 15 to 60% by weight, (III) from 0 to 20% by weight, (IV) 0% by weight or between 5 and 15% by weight, (V) from 0.1 to 2.0% by weight, and/or (VI) from 0.1 to 6.0% by weight.

14. A moulded article produced from a polyamide moulding compound according to claim 1.

15. The moulded article according to claim 14, which is a component in an automobile, in a hot water appliance, in a coffee machine, electric kettle, immersion coil, dishwasher, or washing machine, in measuring, regulating and control technology, or in compressed air controls or valves, or in mechanical engineering.

Description

EXAMPLES

(1) Within the scope of this application, the following measuring methods were used:

(2) The measurements were implemented according to the following standards and on the following test pieces:

(3) Test pieces in the dry state are stored after injection moulding for at least 48 h at room temperature in a dry environment, i.e. over silica gel. Conditioned test pieces are stored according to ISO 1110 (1998-03) for 14 days at 72 C. and 62% relative humidity.

(4) The thermal behaviour (melting point (T.sub.m), melt enthalpy (H.sub.m), glass transition temperature (T.sub.g)) was determined on the granulate by means of the ISO standard 11357-1, -2 and -3 (2013-04). Differential Scanning Calorimetry (DSC) was implemented at a heating rate of 20 K/min.

(5) The relative viscosity (.sub.rel) was determined according to DIN EN ISO 307 (2013-08) on solutions of 0.5 g polymer, dissolved in 100 ml m-cresol at a temperature of 20 C. Granulate is used as sample.

(6) Modulus of Elasticity in Tension, Breaking Stress and Breaking Elongation:

(7) modulus of elasticity in tension, breaking stress and breaking elongation were determined according to ISO 527 (2012-06) with a tensile speed of 1 mm/min (modulus of elasticity in tension) or with a tensile speed of 5 mm/min (breaking stress, breaking elongation) on the ISO tensile bar, standard ISO/CD 3167 (2014-11), type Al, 17020/104 mm at a temperature 23 C., 80 C. and 100 C. in the dry and conditioned state.

(8) The thermostability HDT/A (1.8 MPa) and HDT/C (8.0 MPa) was implemented according to DIN EN ISO 75-1, -2 (2013-04) on the ISO impact bar with the dimension 80104 mm in flat edge position.

(9) Water Absorption:

(10) ISO tensile bars were stored in water at a temperature of 95 C. for the duration of 336 hours. After drying the surface with a cotton cloth, the percentage increase in weight, relative to the initial weight (dry ISO tensile bar), was determined.

(11) Production of the copolyamides, of the moulding compounds and of the moulded articles was effected according to the following synthesis method.

(12) Production of polyamide PA-1 (6T/BACT/66/BAC6)

(13) In a 20 l autoclave, 3.48 kg deionised water was placed and 2.46 kg 1,6-hexanediamine (Ba1), 1.00 kg 1,3-bis-(aminomethyl)cyclohexane (Ba2), 4.20 kg terephthalic acid (Bb1), 0.32 kg adipic acid, (Bb3) and 4.48 g phosphinic acid (50% by weight aqueous solution), as condensation catalyst and 3.2 g Antifoam RD 10% by weight emulsion as defoamer were added. Thereafter the solution was made inert with nitrogen six times. Heating to the reaction temperature of 260 C. took place with agitation. This was effected at a pressure of 32 bar. The batch was kept in the pressure phase for 1.5 hours at the reaction temperature and subsequently discharged with steam via a nozzle. The precondensate was dried for 24 hours at 110 C. and in a vacuum of 30 mbar.

(14) The precondensate was postcondensed in a twin-screw extruder of the company Werner & Pfleiderer, type ZSK 25. For this purpose, cylinder temperatures of 10 to 80 C. were set in the first 4 zones, in the remaining zones cylinder temperatures of 300 to 360 C. in a rising and again falling temperature profile were used. The melt was degassed in the second zone in front of the nozzle by a nitrogen flow. The screw speed of rotation was 250 rpm, the throughput 6 kg/h. The polyamide was discharged as a strand through a nozzle, a nozzle temperature of 330 C. being set. The strand was cooled in a water bath at 80 C. and subsequently granulated. The granulate was dried for 24 hours at 120 C. at reduced pressure (30 mbar), to a water content of below 0.1% by weight.

(15) Polyamides PA-4 and PA-5 were produced according to EP 1 930 372 A2. PA-5 thereby corresponds to comparative example 10.

(16) The polyamides listed in table 1 were used for the polyamide moulding compounds examined in tables 2 and 3.

(17) TABLE-US-00001 TABLE 1 polyamides used Composition T.sub.g T.sub.m Designation Polymer (% by mol) [ C.] [ C.] .sub.rel Component (A) PA 66 RADIPOL A45 260 1.85 PA 6 GRILON F34 222 2.05 PA 610 Polyamide PA610 225 1.95 PA 1010 Polyamide PA1010 220 1.75 PA 46 STANYL TE300 NAT. 294 2.00 PA 12 GRILAMID L25 NAT. 178 2.25 Component (B) PA-1 6T/BACT/66/BAC6 68.5/23.5/6/2 150 325 1.62 PA-2 6I/6T (Grivory G21, EMS- 67/33 125 1.52 CHEMIE, Switzerland) PA-3 6T/6I (Grivory HT XE 3733 NK, 70/30 135 325 1.59 EMS-CHEMIE, Switzerland) PA-4 6I/6T/MACMI/MACMT/PACMI/PACMT/12 40/40/6.5/6.5/2/2/3 160 1.61 PA-5 6I/MACMI/6T/MACMT 76.5/13.5/8.5/1.5 148 1.46

(18) Production of the Polyamide Moulding Compounds

(19) The components indicated in tables 1 to 3 were compounded in the above-mentioned concentrations in a twin-screw extruder of the company Werner and Pfleiderer with a screw diameter of 25 mm with prescribed process parameters (cylinder temperatures: rising from 260 to 290 C.; speed of rotation: 250 rpm; throughput: 12 kg/h). The polyamides of components A and B and also the heat stabiliser were hereby metered into the feed zone, whilst the glass fibres were metered into the polymer melt via a sidefeeder 3 housing units in front of the nozzle. The compounds were drawn off as a strand from a nozzle with 3 mm diameter and granulated after water cooling. The granulate was dried for 24 hours at 110 C. in a vacuum at 30 mbar.

(20) The compounds were then injected with an injection moulding machine Arburg Allrounder 320-210-750 to form sample bodies at cylinder temperatures of 280 to 315 C. and a mould temperature of 110 to 150 C.

(21) TABLE-US-00002 TABLE 2 examples according to the invention Components Unit E1 E2 E3 E4 E5 I PA 66 % by wt. 40.75 37.75 34.75 31.75 25.75 (A) PA 6 % by wt. PA 610 % by wt. PA 1010 % by wt PA 46 % by wt. PA 12 % by wt. I PA 1 % by wt. 9 12 15 18 24 (B) PA 2 % by wt. PA 3 % by wt. PA 4 % by wt. PA 5 % by wt. II Glass fibres % by wt. 50 50 50 50 50 V Stabiliser % by wt. 0.25 0.25 0.25 0.25 0.25 E. mod. in tension 23 C., dry MPa 15,750 16,500 16,000 16,000 16,000 E. mod. in tension 80 C., dry MPa 9,500 9,750 9,750 10,000 11,000 E. mod. in tension 100 C., dry MPa 7,750 8,250 8,500 9,000 9,000 E. mod. in tension 23 C., cond. MPa 13,250 14,750 15,000 15,500 15,500 E. mod. in tension 80 C., cond. MPa 7,500 8,250 8,250 8,500 8,750 E. mod. in tension 100 C., cond. MPa 6,500 6,750 n.d. n.d. 7,000 Breaking stress 23 C., dry MPa 225 245 245 245 245 Breaking stress 80 C., dry MPa 140 145 145 145 145 Breaking stress 100 C., dry MPa 125 125 125 125 125 Breaking stress 23 C., cond. MPa 170 190 190 195 195 Breaking stress 80 C., cond. MPa 100 105 105 105 110 Breaking stress 100 C., cond. MPa 95 95 n.d. n.d. 100 Breaking elongation 23 C., dry % 2.7 2.7 2.5 2.5 2.4 Breaking elongation 80 C., dry % 4.9 4.8 4.5 4.5 3.9 Breaking elongation 100 C., dry % 6.1 5.9 4.5 5.2 5.4 Breaking elongation 23 C., cond. % 3.7 3.5 2.9 2.7 2.6 Breaking elongation 80 C., cond. % 5.5 5.3 5.0 5.1 5.5 Breaking elongation 100 C., cond. % 5.6 5.7 n.d. n.d. 6.1 HDT A (1.8 MPa), dry C. 250 250 250 250 250 HDT C (8 MPa), dry C. 200 200 205 205 210 Water absorption, 336 h, 95 C. % by wt. 3.57 3.53 n.d. n.d. 3.3 in water Components Unit E6 E7 E8 E9 E10 I PA 66 % by wt. 30.47 (A) PA 6 % by wt. 7.28 PA 610 % by wt. 37.75 PA 1010 % by wt. 37.75 PA 46 % by wt. 38.00 PA 12 % by wt. 37.75 I PA 1 % by wt. 12 12 12 12 12 (B) PA 2 % by wt. PA 3 % by wt. PA 4 % by wt. PA 5 % by wt. II Glass fibres % by wt. 50 50 50 50 50 V Stabiliser % by wt. 0.25 0.25 0.25 0 0.25 E. mod. in tension 23 C., dry MPa 16,000 16,000 14,500 15,250 13,250 E. mod. in tension 80 C., dry MPa 8,750 9,250 8,000 10,25 7,000 E. mod. in tension 100 C., dry MPa 7,500 8,000 7,250 8,500 6,500 E. mod. in tension 23 C., cond. MPa 13,000 14,250 13,250 12,750 12,250 E. mod. in tension 80 C., cond. MPa 7,000 7,750 7,500 7,000 6,000 E. mod. in tension 100 C., cond. MPa 6,000 6,500 6,000 6,250 4,750 Breaking stress 23 C., dry MPa 225 225 200 225 170 Breaking stress 80 C., dry MPa 135 135 125 150 105 Breaking stress 100 C., dry MPa 120 120 115 130 95 Breaking stress 23 C., cond. MPa 165 185 175 165 150 Breaking stress 80 C., cond. MPa 95 105 100 95 85 Breaking stress 100 C., cond. MPa 85 95 90 85 75 Breaking elongation 23 C., dry % 2.7 2.9 3.0 2.4 4.5 Breaking elongation 80 C., dry % 5.6 5.9 5.3 3.7 8.5 Breaking elongation 100 C., dry % 6.7 7.2 5.9 4.6 9.8 Breaking elongation 23 C., cond. % 3.8 3.2 3.2 3.3 4.7 Breaking elongation 80 C., cond. % 4.8 5.3 4.6 4.8 9.3 Breaking elongation 100 C., cond. % 6.3 7.2 6.1 4.9 10.4 HDT A (1.8 MPa), dry C. 240 205 185 280 170 HDT C (8 MPa), dry C. 105 155 150 205 135 Water absorption, 336 h, 95 C. % by wt. 3.77 2.15 1.64 4.71 1.34 in water

(22) TABLE-US-00003 TABLE 3 (Comparative examples) Components Unit CE1 CE2 CE3 CE4 CE5 I PA 66 % by wt. 37.75 37.75 37.75 37.75 49.75 (A) PA 6 % by wt. PA 610 % by wt. PA 1010 % by wt. PA 46 % by wt. PA 12 % by wt. I PA 1 % by wt. (B) PA 2 % by wt. 12 PA 3 % by wt. 12 PA 4 % by wt. 12 PA 5 % by wt. 12 II Glass fibres % by wt. 50 50 50 50 50 V Stabiliser % by wt. 0.25 0.25 0.25 0.25 0.25 E. mod. in tension 23 C., dry MPa 15,500 16,250 15,250 15,500 15,750 E. mod. in tension 80 C., dry MPa 8,250 8,750 8,500 7,750 8,000 E. mod. in tension 100 C., dry MPa 5,750 7,750 6,750 n.d. n.d. E. mod. in tension 23 C., cond. MPa 14,500 14,500 14,750 15,250 12,750 E. mod. in tension 80 C., cond. MPa 6,250 6,750 6,750 n.d. 6,750 E. mod. in tension 100 C., cond. MPa 4,250 5,000 5,000 n.d. n.d. Breaking stress 23 C., dry MPa 225 230 220 210 225 Breaking stress 80 C., dry MPa 125 130 130 125 145 Breaking stress 100 C., dry MPa 105 120 120 n.d. n.d. Breaking stress 23 C., cond. MPa 165 175 180 180 165 Breaking stress 80 C., cond. MPa 75 95 100 n.d. 100 Breaking stress 100 C., cond. MPa 70 85 80 n.d. n.d. Breaking elongation 23 C., dry % 2.8 2.4 2.8 2.6 2.9 Breaking elongation 80 C., dry % 6.4 5.3 6.2 6.5 5.4 Breaking elongation 100 C., dry % n.d. 6.6 7.4 n.d. n.d. Breaking elongation 23 C., cond. % 3.3 3.5 3.2 3.4 4.0 Breaking elongation 80 C., cond. % 7.4 6.5 6.9 n.d. 5.1 Breaking elongation 100 C., cond. % n.d. 7.0 7.4 n.d. n.d. HDT A (1.8 MPa), dry C. 230 235 235 230 240 HDT C (8 MPa), dry C. 145 180 160 140 200 Water absorption, 336 h, 95 C. % by wt. 3.74 3.61 3.7 n.d. 4 in water Glass fibres VETROTEX 995 EC 10-4.5, round glass fibres with a diameter of 10 m and a length of 4.5 mm, Owens Corning Stabiliser Irganox 1010 (hindered phenol, CAS: 6683-19-8)

(23) The examples according to the invention comprise the partially crystalline, partially aromatic polyamide PA 6T/BACT/66/BAC6 as partially aromatic, partially crystalline polyamide, which was produced according to the above-indicated method specification. This polyamide corresponds to polyamide (B) of the polyamide mixture which is contained as component (I) in the polyamide moulding compound.

(24) The comparative examples comprise in fact likewise partially aromatic polyamides, however these do not correspond to the polyamides (B) according to the invention.

(25) Surprisingly, it is shown that an increase in the concentration of PA-1 as component (B) (Example E1-E5), with T.sub.g=150 C. and T.sub.m=325 C., effected a constant improvement in the rigidity up to 100 C., dry and conditioned, and continuously reduced the water absorption relative to pure PA 66 (CE5). The breaking elongation at 23 C. thereby decreased only slightly. Even higher concentrations of component (B) would however then impair the processability and further increase the brittleness. Different amorphous polyamides as component (B) (CE1, CE3 and CE4) with a T.sub.g of 125-160 C. showed here, if at all, only slight improvements in the rigidity or water absorption. Likewise, improvements could scarcely be established in CE2 with a partially aromatic, partially crystalline polyamide (T.sub.g=135 C. and T.sub.m=325 C.).

(26) Examples E6-E10 show that PA-1 as component (B) is also compatible with numerous other partially crystalline, aliphatic polyamides, and improves the rigidity up to 100 C., dry and conditioned, with extensive maintenance of the breaking elongation at 23 C. Furthermore, in particular in the case of short-chain aliphatic polyamides (E9), the water absorption is reduced significantly.