METHOD FOR THE PRODUCTION OF STABLE POLYOXYMETHYLENE COPOLYMERS (CPOM)

Abstract

The present invention relates to a method for the deactivation of an acid catalyst during the production process of a polyoxymethylene copolymer (cPOM) by adding triisopropanolamine (tris(2-hydroxypropyl)amine) to a mixture which comprises the polyoxymethylene copolymer (cPOM) and the acid catalyst.

Claims

1. A method for the deactivation of an acid catalyst during the production process of a polyoxymethylene copolymer (cPOM), wherein the method for the deactivation of the acid catalyst comprises the steps: a) providing a first mixture (M1) comprising the polyoxymethylene copolymer (cPOM) and the acid catalyst, b) adding triisopropanolamine to the first mixture (M1) to deactivate the acid catalyst in order to obtain a second mixture (M2) comprising the polyoxymethylene copolymer (cPOM) and a complex of the acid catalyst and triisopropanolamine.

2. The method according to claim 1, wherein the polyoxymethylene copolymer (cPOM) comprises from 60 to 99.99 mol % of —CH.sub.2O— recurring units and from 0.01 to 40 mol % of recurring units according to formula (I) ##STR00009## where R.sup.1 to R.sup.4 are each, independently of one another, a hydrogen atom, a C.sub.1-C.sub.4-alkyl group or a alkoxy-substituted alkyl group having from 1 to 4 carbon atoms and R.sup.5 is a chemical bond, a —CH.sub.2—, —OCH.sub.2—, a C1-C4-alkyl- or C.sub.1-C.sub.4-alkoxy-substituted methylene group or a corresponding oxymethylene group and n is from 0 to 3.

3. The method according to claim 2, wherein step a) comprises the step: a1) polymerization of at least one main monomer selected form the group of cyclic formals, and at least one first comonomer selected from the group of those of the formula (II) ##STR00010## where R.sup.1 to R.sup.4 are each, independently of one another, a hydrogen atom, a C.sub.1-C.sub.4-alkyl group or a alkoxy-substituted alkyl group having from 1 to 4 carbon atoms and R.sup.5 is a chemical bond, a —CH.sub.2—, —OCH.sub.2—, a C.sub.1-C.sub.4-alkyl- or C.sub.1-C.sub.4-alkoxy-substituted methylene group or a corresponding oxymethylene group and n is from 0 to 3, and optionally at least one second comonomer, in the presence of the acid catalyst, in order to provide the first mixture (M1) comprising the polyoxymethylene copolymer (cPOM) and the acid catalyst.

4. The method according to claim 1, wherein the acid catalyst is at least one acid catalyst selected from the group consisting of boron trifluoride, a coordination complex of boron trifluoride with water, a coordination complex of boron trifluoride with a dialkylether and catalytic active transformation product of the aforementioned acid catalyst.

5. The method according to claim 1, wherein the acid catalyst in step a) is present in an amount of from 10 to 150 ppm based on the total weight of the first mixture (M1).

6. The method according to claim 1, wherein the acid catalyst in step a1) is present in an amount of from 10 to 150 ppm based on the total weight of main monomers and the comonomers.

7. The method according to claim 1, wherein the triisopropanolamine in step b) is added in a molar excess in view of the acid catalyst from 25:1 to 1:1.

8. The method according to claim 1, wherein in step b) the triisopropanolamine is added in form of a solution comprising the triisopropanolamine dissolved in at least one solvent.

9. The method according to claim 8, wherein the solution comprises ethylacetate as a solvent.

10. Use of triisopropanolamine for the deactivation of an acid catalyst during the production of a polyoxymethylene copolymer, wherein the acid catalyst is complexed by triisopropanolamine.

11. A method for the production of a polymer molding composition (PM) comprising the steps: a1) polymerization of at least one main monomer selected form the group of cyclic formals, and at least one first comonomer selected from the group of those of the formula (II) ##STR00011##  where  R.sup.1 to R.sup.4 are each, independently of one another, a hydrogen atom, a C.sub.1-C.sub.4-alkyl group or a alkoxy-substituted alkyl group having from 1 to 4 carbon atoms and R.sup.5 is a chemical bond, a —CH.sub.2—, —OCH.sub.2—, a C.sub.1-C.sub.4-alkyl- or C.sub.1-C.sub.4-alkoxy-substituted methylene group or a corresponding oxymethylene group and n is from 0 to 3,  and optionally at least one second comonomer, in the presence of the acid catalyst, in order to provide the first mixture (M1) comprising the polyoxymethylene copolymer (cPOM) and the acid catalyst, b) adding triisopropanolamine to the first mixture (M1) to deactivate the acid catalyst in order to obtain a second mixture (M2) comprising the polyoxymethylene copolymer (cPOM) and a complex of the acid catalyst and triisopropanolamine, c) optionally adding at least one additive to the second mixture (M2).

12. A polymer molding composition (PM) obtained by the method according to claim 11.

13. A polymer molding composition (PM) comprising a polyoxymethylene copolymer (cPOM) and 50 to 700 ppm of the deactivated complex of the catalyst and triisopropanolamine, based on the total weight of the polymer molding composition (PM).

14. Use of the polymer molding composition (PM) according to claim 12 for the production of molded parts.

Description

EXAMPLES

[0085] a. Analytical Methods

[0086] Weight loss N.sub.2 (determination of the weight loss under nitrogen atmosphere): For testing the heat stability, the weight loss at 220° C. under N.sub.2 is determined. It is the weight loss in percent of a weighed sample of about 1.2 g of pellets on heating for 2 h at 220° C. under nitrogen. After cooling, the sample is weighed again and the weight loss is calculated.

MVR (DIN EN ISO 1133-1:2012-03):

[0087] The melt volume-flow rate (MVR) is determined by extruding molten material from the cylinder of a plastometer through a die of specified length and diameter under preset conditions of temperature (190° C.) and load (2.16 kg).

Extractable Formaldehyde (FA) Content:

[0088] The extractable FA content in cPOM granulate is determined as follows. 50 g cPOM granulate and 70 ml water are filled into an Erlenmeyer flask and stirred under reflux for 50 or 100 min. After rapid cooling, the FA content is determined on a Metrohm Titroprozessor 682. Therefore, the pH value is adjusted to pH 9.4 using n/10 sodium hydroxide solution (5 ml) and subsequently, if necessary, n/10 sulfuric acid. Subsequently 5 ml of sodium sulfite solution (136 g Na.sub.2SO.sub.3 dissolved in 1 kg deionized water) are added. After the reaction between Na.sub.2SO.sub.3 and FA the solution is back-titrated to pH 9.4 using n/10 sulfuric acid.

[0089] The Calculation of the FA content is carried out as follows:

mass FA [mg]=consumption H.sub.2SO.sub.4×2×concentration H.sub.2SO.sub.4×mass formaldehyde

FA content [%]=mass FA [mg]/net weight [g, cPOM granulate]×(1 000 000/1 000)×means multiplying operator

[0090] It is assumed, that the reaction follows the reaction scheme shown hereinafter

##STR00008##

Formaldehyde Emission (VDA 275, 1994 Edition, Jul. 1, 1994):

[0091] The manufacture of specimen (test sample) was carried out as follows: In an injection molding machine the cPOM granulate is formed into injection molded plates (40×100×2.5 mm), an injection molding machine is utilized with the following parameters; mass temperature: 200° C., tool wall temperature: 90° C. The test samples are stored before examination in a PE-bag.

[0092] For the determination, the specimens are fixed over distilled water in a sealed (closed) 1-L polyethylene bottle at constant temperature (60° C.) for a defined time. Afterwards the 1-L polyethylene bottle is cooled and the formaldehyde content in the distilled water is determined as follows. A photometric analysis using the so-called acetylaceton method is applied. Therefore, the formaldehyde is converted to diacetyldihydrolutidine using acetylacetone and ammonium acetate. The concentration of the diacetyldihydrolutidine is measured photometrically (the maximum of absorption of diacetyldihydrolutidine is at 412 nm).

[0093] The formaldehyde content is given relative to the dry weight of the specimen (mg/kg=ppm).

Tensile Test (DIN EN ISO 527-2, Juni 2012):

[0094] Tensile bars were injection molded in an injection molding machine at a melt temperature of 200° C. and a mold temperature of 90° C. The tensile test was conducted according to DIN EN ISO 527-2. Mean values of the tensile modulus, the tensile stress at yield, the tensile stress at break, the elongation at yield, the elongation at break and the nominal elongation at break were obtained from ten tensile bars. Exclusively specimens of type 1A were used for all tensile test measurements

Hydrolysis Resistance (100° C.):

[0095] Tensile testing after high-temperature storage of testing bars in water at 100° C. was measured according to ISO 527. Mean values were obtained from three tensile bars at each time.

Heat Ageing Tensile Test (140° C.):

[0096] Tensile testing after high-temperature storage of testing bars in air at 140° C. was measured according to ISO 527. Mean values were obtained from three tensile bars at each time.

Charpy Test (DIN EN ISO 179-1, November 2010):

[0097] Charpy bars (80×10×4 mm3) were injection molded in an injection molding machine at a melt temperature of 200° C. and a mold temperature of 90° C. The Charpy test was carried out according to DIN EN ISO 179-1. The Charpy impact strength values were obtained from ten Charpy bars.

Color of Pellets (DIN EN ISO 11664-4, June 2012):

[0098] The color differences ΔE were determined against a polyoxymethylene standard (L=90.4; a=−1.24 and b=0.54) using the CIELAB formula according to ISO 116644-4. The measurement was performed with CIE standard illuminant D65 and using observing fields of 10° angular subtense.

Total Carbon Emission (TCE Relating to VDA277, 1995 Edition, Jan. 1, 1995):

[0099] The total carbon emission was determined relating to VDA277. An injection molded sheet (60×60×1 mm) was crushed and a weighed quantity (1 g) was stored in a glass vessel (10 ml) for 5 h at 120° C. under air at a pressure of 1013.25-mbar. Subsequently, a defined amount of gas from the vessel was analyzed by headspace GC. The total carbon emission is determined as μg carbon per gram sample.

Specific Migration of Triethanolamine (DIN-EN-1186-3, July 2002):

[0100] The manufacture of the specimens (test samples) is carried out as follows: In an injection molding machine the cPOM granulate is formed into injection molded plates (60×60×2 mm), an injection molding machine is utilized with the following parameters; mass temperature: 200° C., tool wall temperature: 90° C. The test samples are stored before examination in a PE-bag.

[0101] The specific migration of triethanolamine (TEOA) is determined by Fraunhofer IVV (Fraunhofer-Institut für Verfahrenstechnik and Verpackung), 85354 Freising according to the European Norm EN 1186-3 with the following conditions:

Food simulant: 50% ethanol
Contact time and contact temperature: 2 h/reflux (3 repeated contacts)
Contact surface/volume: 0.56 dm.sup.2/50 ml

[0102] The amount of migrated triethanolamine was quantified in the third contact with the simulant by using Fraunhofer IVV method 1.4069. The migration solution was diluted by 1/10 and analyzed by LC-MS with a mixture of ammonium acetate and ethanol as flow agent. For detection, the molecular mass was selected in the positive single reaction monitoring mode and the characteristic daughter ion was detected. Quantification was performed by external calibration. The detection limit of triethanolamine within this method is 0.13 mg/kg.

Specific Migration of Triisopropanolamine (DIN-EN-1186-3, July 2002):

[0103] Manufacture of specimen (test sample): In an injection molding machine the POM granules are formed into injection molded plates (60×60×2 mm), an injection molding machine is utilized with the following parameters; mass temperature: 200° C., tool wall temperature: 90° C. The test samples are stored before examination in a PE-bag.

[0104] The specific migration of triethanolamine was determined by Fraunhofer IVV (Fraunhofer-Institut für Verfahrenstechnik and Verpackung), 85354 Freising according to the European Norm EN 1186-3 with the following conditions:

Food simulant: 50% ethanol
Contact time and contact temperature: 2 h/reflux (3 repeated contacts)
Contact surface/volume: 0.56 dm2/50 ml

[0105] The amount of migrated triisopropanolamine (TIPOA) was quantified in the third contact with the simulant by using Fraunhofer IVV method 1.378. The migration solution was diluted by 1/10 and analyzed by LC-MS with a mixture of formic acid and methanol as flow agent. Quantification was performed by external calibration. The detection limit of triisopropanolamine within this method is 0.005 mg/kg.

Extractable Total Organic Carbon (TOC)/FA Content in Drinking Water

[0106] according to KTW-Guideline (version 7 Mar. 2016)=the Guideline for Hygienic Assessment of Organic Materials in Contact with Drinking Water, notified to the European Commission under no. 2013/470/D, pursuant to Directive 98/34/EEC. The KTW-Guideline contains test protocols and safety requirements for plastics and silicones that come into contact with drinking water. The extraction and analysis was performed by Hygiene-Institut des Ruhrgebiets, Germany.

[0107] The manufacture of the specimens (test samples) is carried out as follows: In an injection molding machine the cPOM granulate is formed into injection molded plates (100 mm×70 mm×2.5 mm), an injection molding machine is utilized with the following parameters; mass temperature: 200° C., tool wall temperature: 90° C. The test samples are stored before examination in a PE-bag.

[0108] The migration tests were carried out at 85° C. (hot-water) according to annex 3 of KTW-Guidelines. The surface/volume ratio was 5 dm.sup.−1.

[0109] The migration water samples were analyzed with the parameters for fittings for pipes with DN 300 mm (conversion factor=1 d/dm).

[0110] The amount of extractable Total Organic Carbon (TOC) was analyzed according DIN EN 1484.

[0111] The amount of extractable formaldehyde (FA) on drinking water was determined as follows. 20 ml of migration solution were filled into a flask and 2 ml of a pararosaniline-solution was added (preparation of pararosaniline solution: 160 mg paraosaniline was solved in 24.0 ml conc. hydrochloric acid and dest. water was filled up to 100 ml). Additionally, 2 ml of a freshly prepared sodium sulfite solution was added (preparation of sodium sulfite solution: 50 mg of sodium sulfite was solved in 50 ml dest. water). The flask was filled up to 25 ml with dest. water, sealed and the flask was shaken manually. The flask was stored for 90 min at 23° C. Within this time the formaldehyde is converted with sodium sulfite and pararosaniline into a red-violet color complex. The concentration of this color complex was measured photometrically (the maximum of absorption of the color complex is at a wavelength of 578 nm).

Residual Content of Deactivator in Polymer

[0112] The manufacture of the specimen (test samples) is carried out as follows: In an injection molding machine the cPOM granulate is formed into injection molded plates (60 mm×60 mm×2 mm), an injection molding machine is utilized with the following parameters; mass temperature: 200° C., tool wall temperature: 90° C. The test samples are stored before examination in a PE-bag.

[0113] The specimens were crushed and about 300 mg of polymer was solved in 5 ml 1,1,1,3,3,3-hexfluoro-2-propanol. Subsequently the flask was filled up with a mixture of water and 1 molar HCl (ratio 100/1) to 10 ml total volume and the mixture was stirred to precipitate the polymer. Afterwards about 30 mg methylamine-HCl was added as internal standard for the measurement. The mixture was filtered (pore width 0.45 urn) and the solution was analyzed with electrophoresis to determine the concentration of TIPOA or TEOA relative to the internal standard. Electrophoresis was performed with 5 mmolar 4-aminopyridine (in H.sub.2SO.sub.4, pH 3.4) as electrolyte at the cathode, +25 kV voltage, 16 μA amperage, temperature 20° C.

b. Materials

[0114] The following components were used:

(1) Raw cPOM [0115] Raw cPOM is taken from a kneader reactor of a polyoxymethylene copolymer production. For the production of the raw cPOM 96.5% by weight of trioxane and 3.5% by weight of dioxolane is used, based on the total amount of the used monomers. The raw cPOM contains beside cPOM, 85 ppm BF.sub.3×OEt.sub.2, 3% by weight of unconverted trioxane and 5% by weight of thermally unstable endgroups, based on the total weight of raw cPOM.
(2) Used amines for the deactivation: [0116] Triethanolamine: technical grade, assay min. 99% by GC, by BASF SE [0117] Triisopropanolamine: technical grade, assay min. 99% by GC, by BASF SE

(3) Additives:

[0118] Irganox 245 FF/Ethylenebis(oxyethylene)bis-(3-(5-tert-butyl-4-hydroxy-m-tolyl)-propionate) (36443-68-2): Irganox 245 FF by BASF SE [0119] Synthetic magnesium silicate (1343-88-0) [0120] Talc (14807-96-6): Hydrous magnesium silicate [0121] EBS/N,N′-Ethylenedi(stearamide) (110-30-5) [0122] PA dicapped: PA6,66-copolymer by BASF SE (molecular weight of 3000, prepared from caprolactam, hexamethylenediamine, adipic acid and propionic acid) [0123] Amorphous 6I/6T-polyamide (25750-23-6) (copolyamide prepared from 1,3-benzenedicarboxylic acid, 1,4-benzenedicarboxylic acid and 1,6-hexanediamine) [0124] Tg=125-130° C. [0125] VZ=81-85 ml/g (in H2SO4) [0126] COOH end groups: 88-135 mmol/kg [0127] NH2 end groups: 40-42 mmol/kg [0128] Ca(OH).sub.2/Calcium hydroxide (1305-62-0) [0129] Glyceryl distearate (68308-54-3)
c. Preparation of the Materials
(1) Production of cPOM Resins with Different Deactivators (Pilot Scale Test): [0130] The specific amine (triisopropanolamine or triethanolamine) was diluted with 20 g water to facilitate homogenous distribution on raw cPOM (the amount of amine in the finished cPOM is shown in table 1). This deactivation solution was added to 10 Ica of raw cPOM. The resulting mixture was held for 30 min. Afterwards 62 g of an additive mixture was added for further stabilization (the concentrations of the additives in the final product were: 0.35% Irganox 245 FF, 0.05% synthetic magnesium silicate (1343-88-0), 0.15% Glyceryl distearate, 0.04% PA dicapped and 0.05% Talc). Afterwards the mixture was extruded in a twin-screw extruder (TEX-30, L/D=40, ϕ=27 mm) with 25 kg/h and 250 rpm. The temperature of the melt was 200° C. at the output. The resulting granules were dried at 120° C. for 6 h to obtain the finished cPOM.

[0131] cPOMs with the following amines and concentrations were tested:

TABLE-US-00001 TABLE 1 Triisopropanolamine (TIPOA) Triethanolamine (TEOA) Example 1 3.4 g (344 ppm in final product; cPOM) Example 2 5.7 g (573 ppm in final product; cPOM) Example 3 8.0 (802 ppm in final product; cPOM) Comparison 1 2.7 g (268 ppm in final product; cPom) Comparison 2 4.5 g (447 ppm in final product; cPOM) Comparison 3 6.3 g (625 ppm in final product; cPOM)
d. Results

TABLE-US-00002 TABLE 2 Example 1 Example 2 Example 3 Compar 1 Compar 2 Compar 3 344 ppm 573 ppm 802 ppm 268 ppm 447 ppm 625 ppm TIPOA TIPOA TIPOA TEOA TEOA TEOA Weight loss N.sub.2 (%) 1.78 n.d. 2.43 1.84 1.92 3.01 MVR (cm3/10′) 10.4 12.2 12.7 10.7 10.6 11.4 Extractable FA 270.0 302.0 310.0 252.0 390.0 776.0 content (H.sub.2O, 100° C., 50 min) (ppm) FA emission (ppm) 110 n.d. n.d. 142 n.d. n.d. dE 1.7 1.8 1.4 1.8 3.3 2.5 dL −1.6 −1.7 −1.2 −1.7 −2.3 −2.2 da 0.4 0.4 0.3 0.4 0.5 0.4 db 0.5 0.7 0.6 0.5 2.2 0.9 L* 88.8 88.7 89.2 88.7 88.1 88.2 a* −0.9 −0.9 −0.9 −0.9 −0.8 −0.9 b* 1.0 1.2 1.2 1.1 2.8 1.5 Tensile modulus 2678 n.d. n.d. 2745 n.d. n.d. (MPa) Tensile stress at 64 n.d. n.d. 64 n.d. n.d. yield (MPa) Tensile stress at 55 n.d. n.d. 55 n.d. n.d. break (MPa) Elongation at yield 9.2 n.d. n.d. 9.1 n.d. n.d. (%) Elongation at break n.d. n.d. n.d. n.d. n.d. n.d. (%) Nom. elongation at 30.2 n.d. n.d. 29.0 n.d. n.d. break (%) Charpy impact 207 n.d. n.d. 200 n.d. n.d. strength +23° C. (kJ/m.sup.2) Charpy notched 6.4 n.d. n.d. 6.1 n.d. n.d. impact strength +23° C. (kJ/m.sup.2) [0132] The results in table 2 show that the use of triisopropanolamine (TIPOA) for the deactivation of the catalyst leads to a lower FA content and a lower FA emission compared to the deactivator triethanoleamine (TEOA) which is used in the state of the art. Moreover, the use of TIPOA has no negative influence on the color and the physical properties of cPOM.

TABLE-US-00003 TABLE 3 Table 3: Results for the hydrolysis resistance at 100° C. Example 1 Comparison 1 344 ppm TIPOA 268 ppm TEOA Tensile Nom. Tensile Nom. Tensile stress elongation Tensile stress elongation modulus at yield at break modulus at yield at break (MPa) (MPa) (%) (MPa) (MPa) (%) 0 2678 63.65 30.21 2745 64.31 29.04  7 d 2053 64.59 28.45 2040 64.64 23.33 14 d 2181 65.88 26.97 2197 66 20.93 21 d 2086 64.54 23.71 2069 64.55 21.14 42 d 2130 64.67 18.54 2136 64.78 16.39 49 d 2089 64.33 22.76 2041 64.15 15.35 56 d 2001 64.47 22.01 1994 64.51 16.12

TABLE-US-00004 TABLE 4 Table 4: Results for the heat ageing tensile test Example 1 Comparison 1 344 ppm TIPOA 268 ppm TEOA Tensile Nom. Tensile Nom. Tensile stress elongation Tensile stress elongation modulus at yield at break modulus at yield at break (MPa) (MPa) (%) (MPa) (MPa) (%) 0 2678 63.65 30.21 2745 64.31 29.04  500 h 2913 67.56 25.29 2935 67.79 20.02  750 h 3065 67.19 19.038 3042 66.18 17.97 1000 h 2875 58.93 5.93 2869 55.81 4.71 [0133] The results in tables 3 and 4 prove that TIPOA leads to cPOM with improved hydrolysis and heat aging performance compared to TEOA.
(2) Production of cPOM Resins with Different Deactivators (Industrial Scale Test): [0134] Raw cPOM was produced using 85 ppm BF.sub.3*OEt.sub.2 in a kneader-based process. [0135] Dioxolane to trioxane ratio used was 3.5:96.5 and methylal was adjusted to produce medium viscosity cPOM with an output of 1750 kg/h. [0136] The amine used in the trials was dosed as 6 wt % solution in ethyl acetate and sprayed on the crushed cPOM. [0137] The removal of the residual monomers and the instable endgroups was done on a twin screw extruder at 230° C./135 rpm. [0138] Additives (concentration in the finished PM): 0.35% Irganox 245 FF, 0.05% synthetic magnesium silicate (1343-88-0), 0.05% Talc, 0.04% amorphous 6116T polyamide (25750-23-6), 0.15% EBS, 0.02% Ca(OH).sub.2

[0139] The following amines and concentrations were tested (table 5):

TABLE-US-00005 TABLE 5 triethanolamine triisopropanolamine Comparison 4 270 ppm in final product; cPOM Example 4 400 ppm in final product; cPOM
e. Results

TABLE-US-00006 TABLE 6 Comparison 4 Example 4 MVR (190° C., 2.16 kg, 5′) 8.7 9.0 pellets Gewichtsverlust unter N2 0.27% 0.13% (222° C., 5 h) Extractable FA content (H2O, 194 ppm 185 ppm 100° C., 50 min) (ppm) Extractable FA content (H2O, 490 ppm 382 ppm 100° C., 100 min) (ppm) FA emission (VDA275)  10 ppm  6 ppm TCE (VDA277)  6 ppm  5 ppm Specific migration 0.65 ppm TEOA 0.32 ppm TIPOA of deactivation agent (acc. DIN-EN-1186-3) Extractable Total 1.60 mg/dm2 × d 1.19 mg/dm2 × d Organic Carbon (TOC)/ 15000 μg/L 13000 μg/L FA content in drinking water acc. KTW Guidelines Residual content of 59 ppm TEOA 22 ppm TIPOA deactivator in polymer Tensile modulus (MPa) 2793 2707 Tensile stress at yield (MPa) 64 64 Tensile stress at break (MPa) 59 59 Elongation at yield (%) 9.9 10.3 Elongation at break (%) Nom. elongation at break (%) 25.4 26.4 Charpy impact 180 212 strength +23° C. (kJ/m.sup.2) Charpy notched 6.2 6.8 impact strength +23° C. (kJ/m.sup.2)

TABLE-US-00007 TABLE 7 Table 7: Results for hydrolysis resistance at 100° C. Comparison 4 Example 4 Tensile Nom. Tensile Nom. Tensile stress elongation Tensile stress elongation modulus at yield at break modulus at yield at break (MPa) (MPa) (%) (MPa) (MPa) (%)  0 d 2793 64.45 25.44 2707 63.9 26.36  7 d 2106 64.7 14.24 2104 64.49 17.92 14 d 2011 62.32 9.28 2012 62.85 11.52 28 d 2042 58.98 7.01 2031 59.8 7.64 56 d 2079 52.01 5.24 2063 57.34 6.59

TABLE-US-00008 TABLE 8 Table 8: Results for heat ageing tensile test at 140° C. Comparison 4 Example 4 Tensile Nom. Tensile Nom. Tensile stress elongation Tensile stress elongation modulus at yield at break modulus at yield at break (MPa) (MPa) (%) (MPa) (MPa) (%)   0 h 2793 64.45 25.44 2707 63.9 26.36  500 h 2882 67.52 20.09 2894 66.38 21.7  750 h 2770 66.49 15.47 2713 66.2 18.36 1000 h 2986 66.28 14.41 2926 66.49 16.66