POLYMER COMPOSITION AND MOLDED PART MADE THEREOF

Abstract

The invention relates to a polyamide polymer; to a polymer composition comprising the polyamide polymer and a fibrous reinforcing agent or a filler, or a combination thereof; to a molded part made of the polymer composition; and to an automotive vehicle comprising a load-bearing structural part made of the molded part. Herein the polyamide polymer has a glass transition temperature (Tg) of at least 145 C. and a dynamic modulus (E), measured at a temperature (Tmod) equal to Tg+15 C., in the range of 100 MPa-700 MPa.

Claims

1. Polyamide polymer having a glass transition temperature (Tg) of at least 145 C. and a dynamic modulus (E), measured at a temperature (Tmod) equal to Tg+15 C., in the range of 100 MPa-700 MPa, wherein both Tg and E are measured by dynamic mechanical thermal analysis (DMTA) according to the method of ASTM-D5026-15.

2. The Polyamide polymer according to claim 1, wherein E at Tmod is in the range of 200 MPa-650 MPa, optionally 300 MPa-600 MPa, and/or wherein the polyamide polymer has a glass transition temperature (Tg) of at least 150 C., optionally in the range of 155 C.-175 C.

3. The Polyamide polymer according to claim 1, wherein the polyamide polymer comprises a semi-crystalline semi-aromatic polyamide having a melting temperature (Tm) of at least 280 C., optionally in the range of 300 C.-350 C.

4. The Polyamide polymer according to claim 1, comprising repeat units, at least 95 mole % of which are derived from diamine and dicarboxylic acid, wherein at least 40 mole %, optionally at least 50 mole %, optionally at least 60 mole % of said repeat units is derived from a cyclic monomer, relative to the molar amount of diamine and dicarboxylic acid.

5. The Polyamide polymer according to claim 4, wherein the cyclic monomer comprises an aromatic monomer, or a cycloaliphatic monomer, or a combination of an aromatic monomer and a cycloaliphatic monomer, optionally a combination of an aromatic dicarboxylic acid and a cycloaliphatic diamine.

6. The Polyamide polymer according to claim 1, wherein the polyamide polymer is a copolyamide or a blend of at least two polyamides, having an overall monomer composition represented by one of the notations XT/XI or XT/XI/YT/YI, XT/XI/RT/RI or XT/XI/YT/YI/RT/RI, wherein X represents a linear aliphatic C4-C5 diamine; Y represents a linear aliphatic diamine with at least 6 carbon atoms; R represents a branched diamine (B) or cyclic diamine (C), or a combination thereof; I represents isophthalic acid; and T represents terephthalic acid; and wherein the polyamide comprises 15-100 mole % of X, 0-80 mole % (Y), and 0-10 mole % (R), relative to the total molar amount of (X)+(Y)+(R), and 20-45 mole % (I) and 55-80 mole % (T), relative to the total molar amount of (I)+(T).

7. The Polyamide polymer according to claim 1, wherein the polyamide polymer is a copolyamide or a blend of at least two polyamides, having an overall monomer composition represented by one of the notations ZT/BT or ZT/BT/ZI/BI, or ZT/BT/CT or ZT/BT/CT/ZI/BI/CI, wherein X represents a linear aliphatic C4-05 diamine Y represents a linear aliphatic diamine with at least 6 carbon atoms, Z represents a linear aliphatic diamine with at least 4 carbon atoms, wherein (Z) is at least one of (X) and (Y) I represents isophthalic acid; T represents terephthalic acid; B represents a branched diamine; and C represents a cyclic diamine; and wherein the polyamide comprises a. 0-30 mole % (I) and 70-100 mole % (T), relative to the total molar amount of (I)+(T), and either b. 25-90 mole % (X), 0-60 mole % (Y), 10-50 mole % (B) and 0-5 mole % (C), relative to the total molar amount of (X)+(Y)+(B)+(C), or c. 15-80 mole % (X), 0-65 mole % (Y), 20-50 mole % (B), and 0-5 mole % (C), relative to the total molar amount of (X)+(Y)+(B)+(C), or d. 0-20 mole % (X), 25-70 mole % (Y), 25-50 mole % (B) and 0-5 mole % (C), relative to the total molar amount of (X)+(Y)+(B)+(C).

8. The Polyamide polymer according to claim 1, wherein the polyamide polymer is a copolyamide or a blend of at least two polyamides, having an overall monomer composition represented by one of the notations ZT/CT, ZT/CT/ZI/CI, ZT/CT/BT, and ZT/CT/BT/ZI/CI/BI, wherein X represents a linear aliphatic C4-05 diamine Y represents a linear aliphatic diamine with at least 6 carbon atoms, Z represents a linear aliphatic diamine with at least 4 carbon atoms, wherein (Z) is at least one of (X) and (Y); I represents isophthalic acid; T represents terephthalic acid; B represents a branched diamine; and C represents a cyclic diamine and wherein the polyamide comprises 0-35 mole % (I) and 65-100 mole % (T), relative to the total molar amount of (I)+(T), and either 30-90 mole % (X), 0-60 mole % (Y), 5-40 mole % (C) and 0-30 mole % (B), relative to the total molar amount of (X)+(Y)+(B)+(C); or 15 mole %-80 mole % (X), 0-70 mole % (Y), 10-40 mole % (C), and 0-30 mole % (B), relative to the total molar amount of (X)+(Y)+(B)+(C); or 0-20 mole % (X), 10-80 mole % (Y), 15-40 mole % (C) and 0-30 mole % (B) and relative to the total molar amount of (X)+(Y)+(B)+(C).

9. The Polyamide polymer according to claim 1, wherein the polyamide comprises a blend of semi-crystalline polyamide and amorphous semi-aromatic polyamide and wherein the amorphous polyamide is an amorphous semi-aromatic polyamide selected from the group consisting of PA-BT, PA-BI, PA-BT/BI, PA-ZI/ZT, PA-CT and PA-CI, and blends and copolymers thereof; wherein T is terephthalic acid, I is isophthalic acid, (Z) is a linear diamine with at least 4 carbon atoms, (B) is a branched aliphatic diamine and (C) is a cyclic diamine.

10. The Polyamide polymer according to claim 6, wherein the branched aliphatic diamine (B) is selected from the group consisting of 2-methyl-1,5-pentanediamine (D), 3-methyl-1,5-pentanediamine, 2,2,4-trimethylhexamethylene diamine and 2,4,4-trimethylhexamethylene diamine, or any combination of two or more thereof; or the cycloaliphatic diamine (C) is selected from the group consisting of one of bis-(aminomethyl)-cyclohexane (BAC), isophoronediamine (IPD), bis(3-methyl-4-aminocyclohexyl)methane (MAC) and bis(4-aminocyclohexyl)methane (PAC), or any combination of two or more thereof; or a combination of the selected branched aliphatic diamine (B) and the selected cycloaliphatic diamine (C).

11. Polymer composition comprising a (a) polyamide polymer; and (b) a fibrous reinforcing agent or a filler, or a combination thereof; wherein the polyamide polymer has a glass transition temperature (Tg) of at least 145 C. and a dynamic modulus (E) at a temperature (Tmod) equal to Tg+15 C., of at most 700 MPa, and wherein both the Tg and E are measured by DMTA, with the method according to ASTM-D5026-15.

12. The Polymer composition according to claim 11, wherein the polyamide polymer is a polyamide polymer comprises a copolyamide or a blend of at least two polyamides, having an overall monomer composition represented by one of the notations XT/XI or XT/XI/YT/YI, XT/XI/RT/RI or XT/XI/YT/YI/RT/RI, wherein X represents a linear aliphatic C4-C5 diamine; Y represents a linear aliphatic diamine with at least 6 carbon atoms; R represents a branched diamine (B) or cyclic diamine (C), or a combination thereof; I represents isophthalic acid; and T represents terephthalic acid; and wherein the polyamide comprises 15-100 mole % of X, 0-80 mole % (Y), and 0-10 mole % (R), relative to the total molar amount of (X)+(Y)+(R), and 20-45 mole % (I) and 55-80 mole % (T), relative to the total molar amount of (I)+(T).

13. The Polymer composition according to claim 11, wherein the fibrous reinforcing agent comprises glass fibers or carbon fibers, or a combination thereof.

14. The Polymer composition according to claim 11, wherein the composition comprises (a) 30-80 wt. %, preferably 40-75 wt. % of the polyamide polymer, and (b) 20-70 wt. %, preferably 25-60 wt. % of the fibrous reinforcing agent or the filler, or the combination thereof; wherein the weight percentages are relative to the total weight of the composition.

15. The Polymer composition according to claim 11, wherein the glass transition temperature (Tg) of the polyamide polymer is at least 150 C., optionally in the range of 155 C.-175 C., and/or the dynamic modulus (E) at the temperature Tmod equal to Tg+15 C. is in the range of 100 MPa-700 MPa, optionally 200 MPa-650 MPa, optionally 300 MPa-600 MPa.

16. Molded part, consisting of comprising or made of a polymer composition according to claim 11.

17. The Molded part according to claim 16, wherein the part is a load bearing structural part for use in an automotive engine compartment, optionally being an engine mount, an engine cover, or a housing for an engine part.

18. Automotive vehicle, comprising a molded part according to claim 16.

Description

MATERIALS AND MATERIAL PREPARATION

[0129] Base polymers were either commercially available polyamide polymers or prepared by conventional methods.

[0130] Copolymers according to the invention and comparative materials were prepared by melt blending different base polymers in an extruder under conditions to obtain a homogeneous blend.

[0131] Polymer compositions were prepared by melt blending the copolymers with glass fibers, in a 50/50 wt. % ratio, in a twin-screw extruder applying conventional compounding conditions.

[0132] Test samples were prepared by injection molding of the polymer compositions in a lab-scale injection molding apparatus equipped with an appropriate mold for the test samples, applying conventional injection molding conditions. Typical 4 mm tensile bars, width 10 mm, were prepared in accordance with ISO 527-1A. For the DMTA measurements, samples with a thickness of 2.0 mm, a width of 4.0 mm and a length of 80 mm were cut out of the ISO-527-1A test bars with a water-cooled diamond saw. The dimensions were measured with the calibrated Heidenhain thickness meter. Prior to the DMTA measurements, the samples were dried for 48 h at 105 C. at 150 mbar nitrogen pressure.

[0133] As test products for testing under fluctuating loads and temperatures beam shaped products with total length of 250 mm and width and height of 30 mm were injection molded using conventional injection molding conditions. The beam shaped products are ribbed and has wall thicknesses of 3.0 mm. Radii in the product are 0.5 mm. A schematic drawing of beam shaped products as tested is shown in FIG. 1.

Test Methods

Glass Transition Temperature (Tg)

[0134] The Tg of the various polymers was measured by DMTA according to the method of ASTM-D5026-15. The dynamic mechanical analyses were carried out using a GABO Eplexor 500N test system at a frequency of 1 Hz and over a temperature ranging from 100 C. to 320 C. with a heating rate of 1 C./min. During the measurements, the storage modulus (E), loss modulus (E) and tangent delta (tan ) were determined as a function of temperature.

Melting Temperature (Tm)

[0135] The melting temperature (Tm) was measured by the DSC method according to ISO-11357-1/3, 2011, on pre-dried samples in an N.sub.2 atmosphere with heating and cooling rate of 20 C./min. Herein Tm has been calculated from the peak value of the highest melting peak in the second heating cycle.

Dynamic Modulus (E)

[0136] The E of the various polymer was measured by DMTA according to the method of ASTM-D5026-15. Herein the E at the temperature Tmod equal to Tg+15 C. The dynamic mechanical analyses were carried out using a GABO Eplexor 500N test system at a frequency of 1 Hz and over a temperature ranging from 100 C. to 320 C. with a heating rate of 1 C./min. During the measurements, the storage modulus (E), loss modulus (E) and tangent delta (tan ) were determined as a function of temperature.

Double Notch Tensile Test

[0137] ISO 527-1A tensile bars (cross-sectional areawidththickness-10.00.24.00.2 mm.sup.2) were notched from two sides with a v-shaped notch with an apex (enclosed) angle of 45 and notch radius of 0.25 mm. Notch depths were 20.05 mm and residual cross-sectional width is 60.02 mm. The residual cross-sectional area is 60.0240.2 mm.sup.2. A schematic drawing of the notched test bars is shown in FIG. 2. The notched bars were tested at room temperature in 10-fold with a gripping length of 115 mm and test speed of 6.6 mm/min. Stress at break (notch strength) was calculated by dividing the maximum recorded force by the residual cross-sectional area.

Bending Test

[0138] Beams were tested at room temperature in 3-point bending with a layup span of 180 mm. The steel indenter has a radius of 15 mm, as well as the two supporting layup points. and the test performed with a loading rate of 10 mm/min. The maximum force (in Newton) prior recorded during the test is reported as the failure strength.

Results

[0139] Base polymers, polymer composition and test data for the polymers and the test samples are summarized in Table 1.

[0140] Further polymers complying with the invention and comparatives not complying with the invention are given in Table 2.

TABLE-US-00001 TABLE 1 different polymer compositions, glass transition temperature (Tg) and mechanical properties above Tg. Mechanical properties Modulus Double Bending Example/ Polymer Polymer Monomer Monomer above notch beam Comparative component I component II Ratio Ratio Tg Tg results test Experiment (wt %) (wt %) Notation Diamines Diamines ( C.) (MPa) (kJ) results 6-T/4T(65/35) DT/DI(60/40) CE-A 100 0 6T/4T 4:6 = n.a. 150 1100 120 Not OK 35:65 EX-I 80 20 4T/6T/4I/6I/DT/DI 4:6:D = T:I = 156 520 163 OK 6:50:20 92:8 EX-II 60 40 4T/6T/4I/6I/DT/DI 4:6:D = T:I = 150 350 160 OK 0:41:39 84:16 6T/4T(65/35) DT CE-B 90 10 4T/6T/DT 4:6:D = n.a. 160 740 150 Not OK 32:58:9 6T/4T(65/35) 6I/6T(70/30) EX-III 60 40 4T/6T/4I/6I 4:6 = T:I = 146 480 174 OK 22:78 72:27

TABLE-US-00002 TABLE 2 Compositions and glass transition temperature (Tg) of other polymers according to the invention (Examples IV-VIII) and polymers not complying with the invention (Comparative Examples C-J) Polymer Polymer Monomer Monomer Example/ component I component II Ratio Ratio Tg Comparative (wt %) (wt %) Notation Diamines Diamines ( C.) 6T/6I(70/30) MACT CE-C 100 0 6T/6I n.a. T:I = 70:30 130 EX-IV 80 20 6T/6I/MACT/MACI 6:MAC = 5:15 T:I = 75:25 145 CE-D 60 40 6T/6I/MACT/MACI 6:MAC = 67:33 T:I = 80:20 165 6T/6I(70/30) IPDT EX-V 70 30 6T/6I/IPDT/IPDI 6:IPD = 74:26 T:I = 78:22 152 CE-E 50 50 6T/6I/IPDT/IPD1 6:IPD = 55:45 T:I = 84:16 171 9T MACT CE-F 100 0 9T n.a. n.a. 125 EX-VI 70 30 9T/MACT 9:MAC = 70:30 n.a. 149 CE-G 50 50 9T/MACT 9:MAC = 49:51 n.a. 172 10T IPDT CE-H 100 0 10T n.a. n.a. 125 EX-VII 60 40 10T/IPDT 10:IPD = 60:40 n.a. 156 CE-I 40 60 10T/IPDT 10:IPD = 40:60 n.a. 179 6T/4T(65/35) DT EX-VIII 70 30 4T/6T/DT 4:6:D = 25:46:29 n.a. 160 6T/4T(65/35) 6I/6T(70/30) CE-J 80 20 4T/6T/4I/6I 4:6 = 28:72 T:I = 7:13 151