Polyamide molding compound

Abstract

The present invention relates to polyamide molding compounds which contain the following components (A) to (C) or consist of these components: (A) 50 to 98% by weight of at least one amorphous or microcrystalline specific polyamide; (B) 2 to 40% by weight of at least one semi-crystalline polyamide which is selected from the group consisting of PA 616, PA 516, PA 1016 and mixtures thereof; and (C) 0 to 16% by weight of at least one additive; the constituent amounts of the components (A) to (C) adding up to 100% by weight. The present invention also relates to molded articles made of these polyamide molding compounds and the use thereof.

Claims

1. A polyamide moulding compound comprising components (A) to (C): (A) 50 to 98% by weight of at least one amorphous or microcrystalline polyamide, selected from the group consisting of PA MACM10, PA MACM12, PA MACM14, PA MACM16, PA MACM18, PA NDT/INDT, PA TMDC10, PA TMDC12, PA TMDC14, PA TMDC16, PA TMDC18, PA PACM10/11, PA PACM10/12, PA PACM12/612, PA PACM12/PACM14/612/614, PA MACMI/12, PA MACMT/12, PA MACMI/MACM12, PA MACMI/MACMN, PA MACMT/MACM12, PA MACMT/MACMN, PA MACM36, PA TMDC36, PA MACMI/MACM36, PA 6I/MACMI/12, PA MACMT/MACM36, PA MACMI/MACMT/12, PA 6I/6T/MACMI/MACMT, PA 6I/6T/MACMI/MACMT/12, PA 6I/6T/MACMI/MACMT/MACM12, PA MACM6/11, PA MACM6/12, PA MACM10/11, PA MACM10/12, PA MACM10/1010, PA MACM12/1012, PA MACM12/1212, PA MACM14/1014, PA MACM14/1214, PA MACM16/1016, PA MACM18/1018, PA 6I/6T/MACMI/MACMT/MACM12/612, PA 6I/6T/MACMI/MACMT/MACM12/12, PA MACMI/MACMT/MACM12/12, PA MACMI/MACMT/MACM12, PA 6I/6T/MACMI/MACMT/12, PA 6I/6T/6N/MACMI/MACMT/MACMN, PA TMDC12/TMDCT/TMDC36, PA TMDC12/TMDCI, PA TMDC12/TMDCI/TMDC36, and PA TMDC12/TMDCT, and copolymers thereof, the MACM being replaceable up to max. 35% by mol by PACM and/or TMDC, relative to the sum of the molar proportions of all the monomers of 100% by mol and/or the laurinlactam being replaceable totally or partially by caprolactam, (B) 2 to 40% by weight of at least one partially crystalline polyamide selected from the group consisting of PA 616, PA 516, and PA 1016; and (C) 0.1 to 20% by weight of at least one additive selected from the group consisting of inorganic and organic stabilisers, antiozonants, light-protection agents, UV absorbers or UV blockers, lubricants, colourants, marking agents, pigments, carbon black, graphite, graphene, carbon nanotubes, photochromic agents, antistatic agents, mould-release agents, condensation catalysts, chain regulators, defoamers, antiblocking agents, chain-lengthening additives, optical brighteners, IR absorbers, NIR absorbers, halogen-containing flame retardants, halogen-free flame retardants, natural layer silicates, synthetic layer silicates, metallic pigments, metal flakes, metal-coated particles, carbon fibres, metal fibres, plant fibres, polymer fibres, whiskers, and mineral fibres; wherein the polyamide moulding compound is free of glass fibres; the quantities of components (A) to (C) adding up in total to 100% by weight; wherein a test piece made of the polyamide moulding compound has a stress crack resistance in toluene, determined according to DIN 53449-3 (1984) bending strip method, of at least 20 MPa; and/or has a stress crack resistance in n-hexane, determined according to DIN 53449-3 (1984) bending strip method, of at least 20 MPa.

2. The polyamide moulding compound according to claim 1, wherein: the proportion of component (A) in the polyamide moulding compound is in the range of 55 to 95.9% by weight, relative to the total weight of the polyamide moulding compound, and/or the proportion of component (B) in the polyamide moulding compound is in the range of 4 to 35% by weight, relative to the total weight of the polyamide moulding compound.

3. The polyamide moulding compound according to claim 2, wherein the proportion of component (A) in the polyamide moulding compound is in the range of 63 to 94.7% by weight relative to the total weight of the polyamide moulding compound, and/or the proportion of component (B) in the polyamide moulding compound is in the range of 5 to 31% by weight, relative to the total weight of the polyamide moulding compound, and/or the proportion of component (C) in the polyamide moulding compound is in the range of 0.3 to 6% by weight, relative to the total weight of the polyamide moulding compound.

4. The polyamide moulding compound according to claim 1, wherein the content of naphthalenedicarboxylic acid in component (A) is 0 to 10% by mol, relative to the sum of the molar proportions of all the monomers of components (A) of 100% by mol; and/or the lactam- and/or ω-amino acid content in component (A) is 0 to 50% by mol, relative to the sum of the molar proportions of all the monomers of component (A) of 100% by mol.

5. The polyamide moulding compound according to claim 1, wherein component (A) is selected from the group consisting of PA MACM10, PA MACM12, PA MACM14, PA MACM16, PA MACM18, PA MACM36, PA TMDC10, PA TMDC12, PA TMDC14, PA TMDC16, PA TMDC18, PA NDT/INDT, PA PACM10/11, PA PACM10/12, PA PACM12/612, PA PACM12/PACM14/612/614, PA MACMI/12, PA MACMT/12, PA MACMI/MACM12, PA MACMT/MACM12, PA MACMI/MACMT/12, PA MACMI/MACMT/MACM12, PA MACMI/MACMT/MACM12/12, PA MACMI/MACMT/MACM12, PA 6I/6T/MACMI/MACMT, PA 6I/6T/MACMI/MACMT/12, PA 6I/6T/MACMI/MACMT/MACM12/12, PA 6I/6T/MACMI/MACMT/MACM12, PA MACM6/11, PA MACM6/12, PA MACM10/11, PA MACM10/12, PA MACM10/1010, PA MACM12/1012, PA MACM12/1212, PA MACM14/1014, PA MACM14/1214, PA MACM16/1016, and PA MACM18/1018, and PA MACM10/PACM10, PA MACM12/PACM12, PA MACM14/PACM14, PA MACM16/PACM16, PA MACM18/PACM18, PA 6I/6T/MACMI/MACMT/PACMI/PACMT/12, and PA 6I/6T/MACMI/MACMT/MACM12/PACMI/PACMT/PACM12, wherein the amount of PACM in each of said PA MACM10/PACM10, PA MACM12/PACM12, PA MACM14/PACM14, PA MACM16/PACM16, PA MACM18/PACM18, PA 6I/6T/MACMI/MACMT/PACMI/PACMT/12, and PA 6I/6T/MACMI/MACMT/MACM12/PACMI/PACMT/PACM12 is up to 35% by mole of a respective sum of the amounts of MACM and PACM, and mixtures or copolymers thereof.

6. The polyamide moulding compound according to claim 5, wherein component (A) is selected from the group consisting of PA MACM12, PA MACM14, PA MACM16, PA MACM18, PA TMDC16, PA TMDC18, PA NDT/INDT, PA PACM12/612, PA PACM12/PACM14/612/614, PA MACMI/12, PA MACMT/12, PA MACMI/MACM12, PA MACMI/MACMT/12, PA MACMI/MACMT/MACM12, PA 6I/6T/MACMI/MACMT/12, PA MACM10/1010, PA MACM12/1012, PA MACM12/1212, PA MACM14/1014, PA MACM16/1016, PA MACM18/1018, PA MACM10/PACM10, PA MACM12/PACM12, PA MACM14/PACM14, PA MACM16/PACM16, PA MACM18/PACM18, PA 6I/6T/MACMI/MACMT/PACMI/PACMT/12 and mixtures thereof.

7. The polyamide moulding compound according to claim 6, wherein component (A) is selected from the group consisting of PA MACM14, PA MACM16, PA MACM18, PA MACMI/12, PA MACMI/MACMT/12, PA MACM10/1010, PA MACM14/1014, PA MACM16/1016, PA MACM18/1018, PA MACM12/PACM12, PA MACM14/PACM14, PA MACM16/PACM16, PA MACM18/PACM18 and mixtures thereof.

8. The polyamide moulding compound according to claim 1, wherein the partially crystalline polyamide (B) is selected from the group consisting of PA 616, PA 1016, and mixtures thereof.

9. The polyamide moulding compound according to claim 8, wherein the partially crystalline polyamide (B) is PA 616.

10. The polyamide moulding compound according to claim 1, wherein the polyamide moulding compound contains precisely one amorphous or microcrystalline polyamide (A) and precisely one partially crystalline polyamide (B).

11. The polyamide moulding compound according to claim 1, wherein the haze of the polyamide moulding compound, measured on a moulded article produced from the polyamide moulding compound (2 mm thick plates with width and length: 60×60 mm) according to ASTM D1003 (2013), is <15%; and/or the transparency, measured on a moulded article produced from the polyamide moulding compound (2 mm thick plates with width and length: 60×60 mm) according to ASTM D1003, is at least 80%.

12. The polyamide moulding compound according to claim 1, wherein a test piece made of the polyamide moulding compound has a modulus of elasticity in tension, determined according to ISO 527 (2012), of at least 1,000 MPa.

13. A moulded article comprising a polyamide moulding compound according to claim 1.

14. The moulded article according to claim 13, which is selected from the group consisting of decorative elements, sports articles, leisure articles, toys, household articles, components of spectacles, furniture coverings, insoles, construction and trim parts for appliances in the sanitary, hygiene and cosmetic field, parts for safety shoes, filter cups, inspection glasses, through-flow meters, bursting discs, containers, housings or housing parts for electrical and electronic appliances, depilators, measuring devices, infrared keys, mobile phones, players, personal digital assistants (PDA), smart phones or storage media, protective covers for mobile phones, trim parts in the computer and telecommunication field, pipes, hoses, films, and components of e-cigarettes.

15. The polyamide moulding compound of claim 1, wherein the at least one additive of component (C) is selected from the group consisting of inorganic stabilisers, organic stabilisers, antiozonants, light-protection agents, UV absorbers or UV blockers, lubricants, colourants, marking agents, pigments, carbon black, graphite, graphene, carbon nanotubes, photochromic agents, antistatic agents, mould-release agents, condensation catalysts, chain regulators, defoamers, antiblocking agents, chain-lengthening additives, optical brighteners, IR absorbers, NIR absorbers, halogen-containing flame retardants, halogen-free flame retardants, metallic pigments, metal flakes, metal-coated particles, carbon fibres, metal fibres, plant fibres, polymer fibres, whiskers, and mineral fibres.

Description

1 MEASURING METHODS

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

(2) Relative Viscosity

(3) The relative viscosity was determined according to ISO 307 (2007) at 20° C. For this purpose, 0.5 g polymer granulate was weighed into 100 ml m-cresol, calculation of the relative viscosity (RV) according to RV=t/t.sub.0 was effected in accordance with section 11 of the standard.

(4) Glass Transition Temperature (Tg) and Melting Point

(5) Determination of the glass transition temperature and of the melting point was effected according to ISO 11357-2 and -3 (2013) on granulate. The differential scanning calorimetry (DSC) was implemented at each of the two heatings with a heating rate of 20 K/min. After the first heating, the sample was quenched in dry ice. Glass transition temperature (Tg) and melting point were determined during the second heating. The temperature at peak maximum was indicated as melting point. The average of the glass transition range which was indicated as glass transition temperature (Tg) was determined according to the “Half Height” method.

(6) Modulus of Elasticity in Tension

(7) Determination of the modulus of elasticity in tension was implemented according to ISO 527 (2012) at 23° C. with a tensile speed of 1 mm/min on an ISO tensile bar (type A1, mass 170×20/10×4) produced according to the standard ISO/CD 3167 (2003).

(8) Stress Crack Resistance

(9) Determination of the stress crack resistance was implemented according to DIN 53449-3 (1984) bending strip method on ISO tensile bars, standard ISO/CD 3167, type A1, 170×20/10×4 mm at a temperature of 23° C. The edge fibre elongation is measured during the 60 second immersion of the ISO tensile bar under stress in the solvent, cracks are visible with the naked eye. For converting the measured edge fibre elongation into the indicated stress, the percentage value of the edge fibre elongation obtained, written as a decimal, is multiplied by the modulus of elasticity in tension (dry, MPa) of the measured material.

(10) Light Transmission and Haze

(11) Light transmission and haze were determined at 23° C. according to ASTM D 1003 (2013) on 60×60 mm plates (width×length) with 2 mm thickness and film gate on a “Haze Gard plus” of the company Byk Gardner with CIE light type C. The light transmission value was indicated in % of irradiated light quantity.

(12) Production of the Test Pieces

(13) The test pieces were produced on an injection moulding machine by the company Arburg, model Allrounder 420 C 1000-250 with a 3-zone standard screw with a diameter of 25 mm. Cylinder temperatures rising and falling from the feed to the nozzle in the range of 250 to 320° C. were thereby used.

(14) The ISO test bars and plates 60×60×2 mm were produced at a mould temperature 80° C., a polished mould being used for the plates.

(15) The test pieces, unless anything else is indicated, were used in the dry state; for this purpose after the injection moulding, they were stored for at least 48 h at room temperature in a dry environment, i.e. over silica gel.

2 STARTING MATERIALS

(16) The materials used in the examples and comparative examples are compiled in tables 1 and 2.

(17) TABLE-US-00001 TABLE 1 Materials used in the examples and comparative examples Components Description Manufacturer Polyamide Amorphous polyamide MACMI/12 made of bis(3- EMS-CHEMIE MACMI/12 (A1) methyl-4-aminocyclo hexyl) methane (32.5% by mol), AG, isophthalic acid (32.5% by mol) and laurinlactam (35% Switzerland by mol) RV 1.56 (measured with 0.5 g in 100 ml m-cresol at 20° C.) glass transition temperature 160° C. Polyamide Amorphous polyamide MACM12 made of bis(3- EMS-CHEMIE MACM12 (A2) methyl-4-aminocyclohexyl)methane and dodecanedioic AG, acid Switzerland RV 1.71 (measured with 0.5 g in 100 ml m-cresol at 20° C.) glass transition temperature 155° C. Polyamide Amorphous polyamide MACM12/PACM12 made of EMS-CHEMIE MACM12/PACM12 bis(3-methyl-4-aminocyclohexyl)methane (35% by AG, (A3) mol), bis(4-aminocyclohexyl)methane (15% by mol) Switzerland and dodecanedioic acid (50% by mol) RV 1.85 (measured with 0.5 g in 100 ml m-cresol at 20° C.) glass transition temperature 145° C. Polyamide Amorphous polyamide MACM16 made of bis(3-methyl- EMS-CHEMIE MACM16 (A4) 4-aminocyclohexyl)methane and 1,16-hexadecanedioic AG, acid Switzerland RV 1.84 (measured with 0.5 g in 100 ml m-cresol at 20° C.) glass transition temperature 140° C. Polyamide 616 Partially crystalline linear aliphatic polyamide 616 EMS-CHEMIE (B1) made of 1,6-hexanediamine and 1,16-hexadecanedioic AG, acid Switzerland RV 1.95 (measured with 0.5 g in 100 ml m-cresol at 20° C.) melting point 196° C. Polyamide 1016 Partially crystalline linear aliphatic polyamide 1016 EMS-CHEMIE (B2) made of 1,10-decanediamine and 1,16- AG, hexadecanedeioic acid Switzerland RV 1.77 (measured with 0.5 g in 100 ml m-cresol at 20° C.) melting point 176° C. Polyamide 12 Partially crystalline linear aliphatic polyamide 12 made EMS-CHEMIE (B3) of laurinlactam AG, RV 1.90 (measured with 0.5 g in 100 ml m-cresol at Switzerland 20° C.) melting point 178° C. RV: relative viscosity measured on a solution of 0.5 g polyamide in 100 ml m-cresol at 20° C.

(18) TABLE-US-00002 TABLE 2 Materials used in the examples and comparative examples Trade Components Description name Manufacturer Antiox- N,N′-hexan-1,6-diylbis[3- Irganox BASF SE, idant 1 (3,5-di-tert-butyl-4- 1098 Germany hydroxyphenylpropionamide CAS-no.: 23128-74-7 Antiox- Tris(2,4-di-tert- Irgafos BASF SE, idant 2 butylphenyl)phosphite 168 Germany CAS-no.: 31570-04-4

3 EXAMPLES AND COMPARATIVE EXAMPLES

3.1 General Production Specification

(19) The production of polyamides (A) or polyamides (B1) and (B2) is effected in a known manner in known, agitatable pressure autoclaves with a receptacle and a reaction vessel.

(20) In the receptacle, deionised water is received and the monomers and any additives are added. Thereafter, the solution is made inert multiple times with nitrogen gas. With agitation, heating takes place to 180 to 230° C. under adjusting pressure in order to obtain a homogeneous solution. This solution is pumped through a sieve into the reaction vessel and heated there to the desired reaction temperature of 270 to 310° C. at a pressure of max. 30 bar. The batch is retained in the pressure phase for 2 to 4 hours at the reaction temperature. In the subsequent pressure-reducing phase, the pressure is reduced to atmospheric pressure within 1 to 2.5 hours, the temperature being able to drop slightly. In the following degassing phase, the batch is retained at atmospheric pressure for 1 to 2.5 hours at a temperature of 270 to 300° C. The polymer melt is discharged in strand form, cooled in the water bath at 15 to 80° C. and granulated. The granulate is dried at 80 to 120° C. under nitrogen or in a vacuum to a water content of less than 0.1% by weight.

(21) Suitable catalysts for accelerating the polycondensation reaction are phosphorus-containing acids, such as for example H.sub.3PO.sub.2, H.sub.3PO.sub.3, H.sub.3PO.sub.4, the salts thereof or organic derivatives. The catalysts are added in the range of 0.01 to 0.5% by weight and preferably 0.03 to 0.1% by weight, relative to the polyamide.

(22) Suitable defoamers for avoiding the formation of foam during degassing are aqueous 10% emulsions which include silicones or silicone derivatives and are used in quantities of 0.01 to 1.0% by weight, preferably 0.01 to 0.10% by weight, relative to the polyamide.

(23) Adjustment of the relative viscosity and hence the molar mass can be effected in a known manner, e.g. via monofunctional amines or carboxylic acids, and/or difunctional diamines or dicarboxylic acids as chain regulators. The chain regulators can be used individually or in combination. The normal usage quantity of the monofunctional chain regulators is at 0.1 to 2% by mol, relative to 100% by mol for the polyamide.

3.2 General Production- and Processing Specification for the Polyamide Moulding Compounds

(24) For production of the polyamide moulding compound according to the invention, components (A), (B) and possibly (C) are mixed on normal compounding machines, such as e.g. single- or twin-screw extruders or screw kneaders. The components are thereby metered individually via gravimetric metering scales into the feed or respectively into a side feeder or supplied in the form of a dry blend.

(25) If additives (component (C)) are used, these can be introduced directly or in the form of a master batch. The carrier material of the master batch concerns preferably a polyamide or a polyolefin. Amongst the polyamides, there is suitable in particular for this purpose the polyamide of the respective component (A).

(26) For the dry blend production, the dried granulates of components (A), (B) and possibly (C) are mixed in a closed container. This mixture is homogenised by means of a tumble mixer, eccentric mixer or tumble dryer for 10 to 40 minutes. In order to avoid moisture absorption, this can be effected under dried protective gas.

(27) The compounding is effected at set cylinder temperatures of 250 to 320° C., the temperature of the first cylinder being able to be set below 170° C. Degassing can take place in front of the nozzle. This can be effected by means of vacuum or atmospherically. The melt is discharged in strand form, cooled in the water bath at 10 to 80° C. and subsequently granulated. The granulate is dried at 80 to 120° C. under nitrogen or in a vacuum to a water content of below 0.1% by weight.

(28) Processing of the polyamide moulding compounds according to the invention by injection moulding is effected at cylinder temperatures of 250 to 320° C., a temperature profile rising and falling from the feed to the nozzle being able to be used. The mould temperature is set to a temperature of 40 to 140° C., preferably 60 to 120° C.

3.3 Production of the Polyamide Moulding Compound According to Example 1

(29) The dried granulates of components (A) and (B) and additives (C) were mixed to form a dry blend, and in fact in the ratio indicated in table 3. This mixture was homogenised for approx. 20 minutes by means of a tumble mixer.

(30) The polyamide moulding compound was produced on a twin-screw extruder of the company Collin type ZK 25T TL. The dry blend was thereby metered into the feed via metering scales.

(31) The temperature of the first housing was set to 150° C., that of the remaining housings to 270 to 290° C. A speed of rotation of 150 rpm and a throughput of 4 kg/h was used. Degassing did not take place. The melt strand was cooled in the water bath, cut, and the obtained granulate was dried at 90° C. for 24 h in a vacuum (30 mbar) to a water content of below 0.1% by weight.

3.4 Examples and Comparative Examples

(32) In the following tables 3 and 4, the results of the examples and comparative examples according to the present invention are compiled.

(33) TABLE-US-00003 TABLE 3 Examples. Examples Unit 1 2 3 4 5 6 7 Components PA MACMI/12 (A1) % by weight 69.65 89.65 — — — — — PA MACM12 (A2) % by weight — — 69.65 — — — — PA MACM12/ % by weight — — — 69.65 79.65 79.65 — PACM12 (A3) PA MACM16 (A4) % by weight — — — — — — 79.65 PA 616 (B1) % by weight 30 10 30 30 20 — 20 PA 1016 (B2) % by weight — — — — — 20 — Antioxidant 1 % by weight 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Antioxidant 2 % by weight 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Measured values Haze % 0.7 0.5 0.6 2.0 1.5 2.3 9.7 Light transmission % 93.1 93.5 93.8 93.5 93.7 92.5 86.1 Modulus of elasticity MPa 1,880 1,990 1,480 1,475 1,450 1,470 1,340 in tension Stress crack resistance toluene MPa 29 20 26 59 54 59 54 n-hexane MPa 42 35 33 26 25 26 34

(34) TABLE-US-00004 TABLE 4 Comparative examples. Comparative examples Unit 8 9 10 11 Components Polyamide MACMI/12 (A1) % by weight 69.65 — — — Polyamide MACM12 (A2) % by weight — 69.65 — — Polyamide MACM12/PACM12 (A3) % by weight — — 69.65 79.65 Polyamide 12 (B3) % by weight 30 30 30 20 Antioxidant 1 % by weight 0.25 0.25 0.25 0.25 Antioxidant 2 % by weight 0.1 0.1 0.1 0.1 Measured values Haze % 0.7 0.8 0.6 0.5 Light transmission % 92.8 93.5 93.3 93.5 Modulus of elasticity in tension MPa 1,950 1,580 1,560 1,580 Stress crack resistance toluene MPa 20 24 20 16 n-hexane MPa 24 32 31 36

4. DISCUSSION OF THE RESULTS

(35) The moulding compounds of examples 1 to 7 (table 3) according to the invention show, relative to the moulding compounds of the comparative examples 8 to 11 (table 4), better stress crack resistances with the same or even better optical properties. This emerges particularly clearly from comparison of examples 1 or 2 with comparative example 8, PA MACMI/12 being used as polyamide (A) and PA 616 being used as polyamide (B) in examples 1 and 2, whereas comparative example 8 uses PA 12. The moulding compound of example 2 shows in fact, with a third of the addition quantity of polyamide 616 as component (B), better stress crack resistances than the moulding compound of comparative example 8 with polyamide 12 as component (B). In addition, also the haze and the light transition of the moulding compound of example 2 are improved relative to those of comparative example 8.

(36) The combination of very good stress crack resistances and very good optical properties can be achieved therefore only by the specific blend, according to the claim, of polyamides (A) and (B). Blends of an amorphous polyamide and the frequently used partially crystalline polyamide 12 in contrast produce poorer properties.