Heat resistant toughened thermoplastic composition for injection molding
Injection molded parts with a small dimension that exhibit high heat resistance are described. Thermoplastic compositions that can be utilized to form the injection molded parts are described. The thermoplastic composition includes a polyarylene sulfide and a crosslinked impact modifier. The thermoplastic composition can also include siloxane polymers, thermoplastic elastomers, or other additives that can further improve the characteristics of the injection molded parts.
1. A fastener that is a cable tie, clip, band, harness, tape, clamp, cable tie saddle, or a combination thereof, wherein the fastener includes an injection molded part having a thickness of about 100 millimeters or less, the fastener containing
a thermoplastic composition formed by melt processing
(i) linear polyarylene sulfide containing less than about 1 mol. % of cross-linking units based on the total monomer units of the polyarylene sulfide,
(ii) from 10 wt. % to 35 wt. % of an epoxy-functionalized impact modifier, and
(iii) from 0.5 wt. % to 2 wt. % of a polyfunctional crosslinking agent that includes a dicarboxylic acid,
wherein melt processing forms a crosslinked epoxy-functionalized impact modifier that is a reaction product of epoxy-functionalized monomer units and the polyfunctional crosslinking agent, and
wherein the thermoplastic composition exhibits a tensile elongation at break of about 50% or more as determined in accordance with ISO Test No. 527 at a temperature of 23° C. and at a speed of 50 mm/min,
wherein the injection molded part exhibits a notched Charpy impact strength of about 3 kJ/m 2 or greater as measured according to ISO Test No. 179-1 at a temperature of 23° C., and
wherein the injection molded part exhibits about 60% or more strength retention following heat aging at 165° C. for 1000 hours.
2. The fastener of claim 1 , the injection molded part exhibiting a notched Charpy impact strength of about 8 kJ/m 2 or greater as measured according to ISO Test No. 179-1 at a temperature of −30° C.
3. The fastener of claim 1 , wherein the injection molded part meets the V-0 flammability standard at a thickness of 0.2 millimeters.
4. The fastener of claim 1 , wherein the injection molded part exhibits a flexural modulus of about 2500 MPa or less as determined according to ISO Test No. 178.
5. The fastener of claim 1 , wherein the polyarylene sulfide is a polyphenylene sulfide.
6. The fastener of claim 1 , wherein the composition comprises one or more fillers.
7. The fastener of claim 6 , wherein the one or more fillers comprises fibrous fillers.
8. The fastener of claim 1 , wherein the impact modifier includes methacrylic monomer units that contain an epoxy functionality.
9. The fastener of claim 8 , wherein the impact modifier further includes α-olefin monomer units.
10. The fastener of claim 9 , wherein the impact modifier further includes methacrylic monomers units that are not epoxy-functionalized.
11. The of claim 1 , wherein the dicarboxylic acid includes terephthalic acid.
12. The fastener of claim 11 , wherein the crosslinking agent is supplied following distribution of the impact modifier with the polyarylene sulfide.
13. The fastener of claim 1 , wherein polyarylene sulfides constitute from about 20% wt. % to about 90 wt. % by weight of the composition.
14. The fastener of claim 1 , wherein the thermoplastic composition contains an additional polymer.
15. The fastener of claim 14 , wherein the additional polymer is a siloxane polymer.
16. The fastener of claim 15 , wherein the siloxane polymer is an ultrahigh molecular weight polydimethylsiloxane.
17. The fastener of claim 14 , wherein the thermoplastic composition further comprising silica, a silane coupling agent, or a combination thereof.
18. The fastener of claim 14 , wherein the additional polymer is a thermoplastic elastomer.
19. The fastener of claim 18 , wherein the thermoplastic elastomer has a repeating structure represented by (A-B) n , wherein A is a hard segment and B is a soft segment.
20. The fastener of claim 19 , wherein the thermoplastic elastomer comprises alternating blocks of polyamide and polyether.
21. The fastener of claim 14 , wherein the additional polymer constitutes from about 0.1 wt. % to about 30 wt. % of the thermoplastic composition.
22. The fastener of claim 1 , wherein the impact modifier constitutes from 15 wt. % to about 35 wt. % of the thermoplastic composition.
23. The fastener of claim 1 , wherein the fastener is a cable tie.
24. The fastener of claim 23 , wherein the cable tie has a head and distal end, wherein the head of the tie defines a slot that is configured to receive the distal end.
25. The fastener of claim 24 , wherein the cable tie further includes a series of teeth.
26. The fastener of claim 25 , wherein the slot includes a pawl that engages the teeth.