INJECTION MOLDED PARTS

Abstract

The invention relates to an injection molded part comprising a composition comprising: a. Polyarylene sulfide (PAS) in an amount of between 50 wt % and 90 wt %; b. Glass fibers in an amount of between 10 wt % and 50 wt %; wherein the composition has a sodium content of at most 3500 ppm as measured by Inductively coupled plasma atomic emission spectroscopy (ICP-AES) and wherein the composition has a iodine content of at most 100 ppm as measured by X-ray fluorescence (XRF) and wherein the weight percentage and ppm is with respect to the total weight of the composition. The invention further relates to a fuel cell comprising the injection molded part.

Claims

1. Injection molded part comprising a composition comprising: a. Polyarylene sulfide (PAS) in an amount of between 50 wt % and 90 wt %; b. Glass fibers in an amount of between 10 wt % and 50 wt %; wherein the composition has a sodium content of at most 3500 ppm as measured by Inductively coupled plasma atomic emission spectroscopy (ICP-AES) and wherein the composition has a iodine content of at most 100 ppm as measured by X-ray fluorescence (XRF) and wherein the weight percentage and ppm is with respect to the total weight of the composition.

2. Injection molded part according to claim 1, wherein the amount of PAS is between 60 wt % and 80 wt %, and the amount of glass fibers is between 20 wt % and 40 wt %, wherein the weight percentage is with respect to the total weight of the composition.

3. Injection molded part according to claim 1, wherein the composition has a sodium content of at most 2000 ppm as measured by Inductively coupled plasma atomic emission spectroscopy (ICP-AES)

4. Injection molded part according to claim 1, wherein the PAS has a sodium content of at most 500 ppm with respect to the total weight of the PAS.

5. Injection molded part, according to claim 1, wherein the glass fibers have a sodium content of at most 3000 ppm with respect to the total weight of the glass fiber.

6. Injection molded part according to claim 1, wherein the glass fibers have a sodium content of at most 800 ppm with respect to the total weight of the glass fiber.

7. Injection molded part according to claim 1, wherein the PAS has a crystallization temperature of at least 230° C. measured by DSC according to the method of ISO 11357-1/3 (2009) with a scan rate of 10° C./min heating the composition to 320° C., and keeping the composition for 3 mins at 320° C. under nitrogen, and subsequently cooling the composition at the same scan rate to record the cooling crystallization temperature in the first cooling cycle.

8. Injection molded part according to claim 1, wherein the composition has a tensile strength on an injection molded tensile bar with 4 mm thickness of at least 160 MPa, measured according to ISO 527-1A 5 mm/min at 23° C., after an exposure to water vapor in an autoclave at a temperature of 110° C. during 1000 hours, preferably at least 165 MPa, more preferred at least 170 MPa.

9. Injection molded part according to claim 1, wherein the composition has an elongation at break on an injection molded tensile bar with 4 mm thickness of at least 1.2%, measured according to ISO 527-1A 5 mm/min at 23° C., after an exposure to water vapor in an autoclave at a temperature of 110° C. during 1000 hours, preferably at least 1.3%, more preferably at least 1.4% even more preferred at least 1.5% and most preferred at least 1.6%.

10. Injection molded part according to claim 1, wherein the polyarylene sulfide is polyphenylene sulfide.

11. Injection molded part according to claim 1, wherein the composition further comprises a coupling agent in an amount of between 0.1 wt % and 1.0 wt %, with respect to the total weight of the composition.

12. Injection molded part according to claim 11, wherein the coupling agent is aminoalkoxylsilane, γ-aminopropyltriethoxysilane and/or γ-aminopropyltrimethoxysilane.

13. Fuel cell comprising the injection molded part according to claim 1.

14. Method for preparing a composition comprising polyarylene sulfide and glass fibers, wherein the composition has a sodium content of at most 3500 ppm as measured by Inductively coupled plasma atomic emission spectroscopy (ICP-AES) and wherein the composition has a iodine content of at most 100 ppm as measured by X-ray fluorescence (XRF) and wherein the weight percentage and ppm is with respect to the total weight of the composition, comprising the steps of heating the PAS to a temperature above its melting temperature, for example with an extruder, and subsequently adding glass fibers to obtain a mixture, after which the mixture is cooled and may be suitably pelletized.

15. Method according to claim 14, wherein a coupling agent being aminoalkoxylsilane, γ-aminopropyltriethoxysilane and/or γ-aminopropyltrimethoxysilane is dosed to the PAS together with the glass fibers.

Description

EXAMPLES

Materials Used:

Glass Fibers:

[0037] NEG ECS03T-747H/R, available from NEG, with a sodium content of 4500 ppm with respect to the glass fiber. Iodine content was below the detection limit.
DS8800-11P 4 mm, available from 3B, with a sodium content of 400 ppm with respect to the glass fiber. Iodine content was below the detection limit.

PPS:

[0038] PPS A and PPS 1 were produced in accordance to the process as described in U.S. Pat. No. 3,919,177. In this process, para-dichlorobenzene was reacted with NaHS in N-methyl-2-pyrrolidone solvent under high temperature about 250° C. till the desired Mw was reached. PPS 1 was further subjected to a washing step after polymerization with water at a temperature of 80° C. to lower the amount of —SNa end groups by partially converting them to —SH, which led to the low sodium content.
The molecular characteristics, the crystallization temperatures, the sodium and iodine contents of PPS A and PPS 1 were determined according to the methods as described in the specification above.
The results are indicated below.

TABLE-US-00001 M.sub.n M.sub.w M.sub.z M.sub.w/M.sub.n M.sub.z/M.sub.w Tc Sample (g/mol) (g/mol) (g/mol) (—) (—) (° C.) PPS A 20000 41000 64000 2.1 1.6 230 PPS 1 30700 49300 71200 1.6 1.4 240
PPS A with a sodium content of 1500 ppm, which is 0.15 wt % with respect to the total weight of the PPS.
PPS 1 with a sodium content of 400 ppm.
PPS A and PPS 1 have a iodine content below the detection limit.
Comparative material B: A504X90 (C) available from Toray. It contains PPS with a sodium content of 1700 ppm, based on the total weight of the PPS and 40 wt % glass fibers. Iodine content of Comparative material B is below the detection limit.
Comparative material C: 1140L4 available from Celanese. This composition contains 40 wt % of glass fiber and has a sodium content of 0.47 wt % (4700 ppm) based on the total weight of the composition. Iodine content of Comparative material C is below the detection limit.

TABLE-US-00002 TABLE 1 compositions Total sodium Type of glass fiber Type of PPS - Coupling agent content of and amount [wt % and amount [wt % and amount [wt % composition [ppm with respect to with respect to with respect to with respect to composition] composition] composition] composition] Comparative A NEG ECS03T- PPS A (3-Aminopropyl)tri- 3700 747H/R 59.5 wt % ethoxysilane 40 wt % 0.5 wt % Comparative B 40 wt % 4100 Comparative C 40 wt % 4700 Example 1 DS8800-11P PPS 1 (3-Aminopropyl)tri- 1000 4 mm 59.5 wt % ethoxysilane 40 wt % 0.5 wt %

[0039] The compositions were prepared by mixing the ingredients as present in Table 1, except for Comparative B which was obtained from Toray, and Comparative C, which was obtained from Celanese.

[0040] A mixture of PPS and coupling agent was combined with glass fibers, to avoid breakage of the glass fibers, and melt compounded using a twin screw extruder at temperatures of from about 315° C. to about 420° C. The molten composition was extruded into strands and passed through a water bath prior to being chopped into pellets. The resulting pellets were dried at 140° C. for at least 4 hours, and were then molded into test articles testing for example e.g. tensile strength testing, tensile modulus testing, tensile strain testing by injection molding at melt temperatures of 315° C. to 345° C. with mold cavity surface temperatures of 135° C. to 150° C.

[0041] All tensile testing in the case of Tables 2 were conducted in accordance with standard test methods ISO 527-2. The test articles were subjected to tensile testing to obtain initial property values (TO hours values), and the data are displayed in Tables 2-1 to 2-6. Test articles were subjected to water glycol (W/G) mixture (50%/50% vol. %/vol. %). W/G aging of the test articles was conducted by fully immersing the test articles (e.g., molded test specimens) in W/G within a closed stainless steel pressure vessel heated to 135±2° C. using the steam heating, over various time periods (e.g., 1 week, 2 weeks, and 6 weeks), as noted in Tables 2-1 to 2-3, to yield aged test articles. The aged test articles were then recovered and subjected to tensile testing to obtain final property values, and the data are displayed in Tables 2-1 to 2-3 (tensile properties, aged at 135° C., tested at 23° C.). “n.m.” in the tables stands for not measured.

TABLE-US-00003 TABLE 2-1 Tensile test ISO 527-1A 5 mm/min, @ 23° C. - Tensile-Modulus Tensile-Modulus (MPa) (Ageing hrs @ 135° C.) T0 168 hours 336 hours 6 weeks Comparative A 14745 15278 15136 14884 Comparative B 15276 14373 14400 n.m. Example 1 14659 14863 14865 14376

TABLE-US-00004 TABLE 2-2 Tensile test ISO 527-1A 5 mm/min, @ 23° C. - Tensile strength TS (MPa) (Ageing hrs @ 135° C.) T0 168 hours 336 hours 1008 hours Comparative A 191 175 172 158 Comparative B 184 148 137 n.m. Example 1 203 190 193 188

TABLE-US-00005 TABLE 2-3 Tensile test ISO 527-1A 5 mm/min, @ 23° C. - Elongation at break (eab) eab % (Ageing hrs @ 135° C.) T0 168 hours 336 hours 1008 hours Comparative A 1.84 1.46 1.44 1.3  Comparative B 1.61 1.24 1.15 n.m. Example 1 2.26 1.84 1.94 1.88

Autoclave Ageing A 110° C.

[0042] The test articles were subjected to tensile testing to obtain initial property values, referred to as T0 in the tables, and the data are displayed in Table 2-4 to 2-6. Test articles were subjected to water steam @ 110° C. in an autoclave, over various time periods namely after 500 hours and 1000 hours, as noted in Table 2-4 to 2-6, to yield aged test articles. The aged test articles were then recovered and subjected to tensile testing to obtain final property values, and the data are displayed in Table 2-4 to 2-6 showing tensile properties, aged at 110° C. and measured at 23° C.

TABLE-US-00006 TABLE 2-4 Tensile test ISO 527-1A 5 mm/min, measured @ 23° C. - Tensile-Modulus Tensile modulus (MPa) (Ageing hrs @ 110° C.) T0 500 hrs 1000 hrs Comparative A 15135 14414 15001 Comparative C 15236 14034 14431 Example 1 14659 14527 14061

TABLE-US-00007 TABLE 2-5 Tensile test ISO 527-1A 5 mm/min, measured @ 23° C. - Tensile strength TS (MPa) (Ageing hrs @ 110° C.) T0 500 hrs 1000 hrs Comparative A 198 151 157 Comparative C 188 123 109 Example 1 203 173 175

TABLE-US-00008 TABLE 2-6 Tensile test ISO 527-1A 5 mm/min, measured @ 23° C. - eab eab % (Ageing hrs @ 110° C.) T0 500 hrs 1000 hrs Comparative A 1.69 1.20 1.16 Comparative C 1.66 1.00 0.90 Example 1 2.26 1.60 1.70
Tables 2-1 to 2-3 clearly show that the E-modulus of the various samples is similar. Tensile strength and EAB are highest for Example 1, and also remain higher after prolonged exposure to W/G. Comparative B showed a dramatic decrease for tensile strength and EAB, that these were no longer measured after 1008 hours.
Tables 2-4 to 2-6 show that the E-modulus of the various samples is similar. Also here, Tensile strength and EAB are highest for Example 1, and also remain higher after prolonged exposure to water steam. Comparative A and C showed a dramatic decrease for tensile strength and EAB, in contrast to Example 1, for which the values were still sufficient, even after 1000 hours.

Leaching Experiments

Sample Information

[0043] Three compositions were used for the leaching experiments as tensile bars, namely Comparative A, Comparative B and Example 1, as described in Table 1. Test specimen of ½ tensile bar were used. The test specimen had the following properties; 4.0 mm thick, total surface area 32 cm.sup.2. ISO527-1A was used for the test specimen.

Leaching Incubation Protocol:

[0044] 1) Specimen was put in 100 ml of ultrapure water (=32 mm.sup.2/ml); [0045] 2) Oven aging at 90° C. in closed Teflon™ FEB bottle; [0046] 3) Incubation for 6 weeks @ 90° C., the 100 ml was subjective to ICP-AES measurement, a reference sample with Blanco incubation of 100 ml in Teflon bottle included as well.

ICP-AES Analysis Set-Up for Leaching Results

[0047] ˜15 ml of liquid was sampled for the ICP-AES screening, The samples were acidified with 0.5 ml HNO.sub.3 prior to the measurements. A quantitative multi-element screening was performed with a certified reference standard. Measurements were performed with an iCAP6500 ICP-AES from Thermo Scientific. The main 5 leaching elements of Si, Ca, Al, K, and Na are presented in Table 3. Significant differences in leaching behavior were observed between the different PPS samples.

TABLE-US-00009 TABLE 3 Leaching results Concentration of element (mg/kg) Si Ca Al Mg Na Comparative A 8.49 5.62 2.18 0.33 0.33 Comparative B 10 6.78 2.46 0.38 0.25 Example 1 1.65 0.97 0.04 0.1 0.01 Blanco (Ref.) 0.02 <0.01 <0.01 <0.01 <0.01
Comparative B clearly showed worst leaching performance over all reported elements, closely followed by Comparative A. Example 1 clearly exhibited lowest leaching content over all reported elements.