Liquid crystalline polymer composition for camera modules
A polymer composition that is capable of exhibiting a unique combination of ductility (e.g., tensile elongation at break), impact strength (e.g., Charpy notched impact strength), and dimensional stability is provided. For example, the polymer composition may contain a liquid crystalline polymer in combination with an epoxy-functionalized olefin copolymer and an inorganic particulate material.
1. A polymer composition comprising:
100 parts by weight of at least one liquid crystalline polymer;
from about 50 to about 90 parts by weight of an inorganic particulate material having a hardness value of about 2.5 or more based on the Mohs hardness scale and a median particle size of from about 0.1 to about 35 micrometers; and
from about 1 to about 15 parts by weight of an epoxy-functionalized olefin copolymer; wherein
the polymer composition exhibits a tensile elongation at break of about 3.5% or more, as determined in accordance with ISO Test No. 527:2012 at 23° C.
2. The polymer composition of claim 1 , wherein liquid crystalline polymers constitute from about 20 wt. % to about 80 wt. % of the polymer composition.
3. The polymer composition of claim 1 , wherein the liquid crystalline polymer comprises repeating units derived from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, hydroquinone, 4,4′-biphenol, acetaminophen, or a combination thereof.
4. The polymer composition of claim 1 , wherein the inorganic particulate material comprises calcium pyrophosphate, calcium sulfate, barium sulfate, or a combination thereof.
5. The polymer composition of claim 1 , wherein the inorganic particulate material constitutes from about 20 wt. % to about 60 wt. % of the polymer composition and the epoxy-functionalized copolymer constitutes from about 1 wt. % to about 20 wt. % of the polymer composition.
6. The polymer composition of claim 1 wherein the epoxy-functionalized olefin copolymer contains an ethylene monomeric unit.
7. The polymer composition of claim 1 , wherein the epoxy-functionalized olefin copolymer contains an epoxy-functional (meth)acrylic monomeric component.
8. The polymer composition of claim 7 , wherein the epoxy-functional (meth)acrylic monomeric component is derived from glycidyl acrylate, glycidyl methacrylate, or a combination thereof.
9. The polymer composition of claim 7 , wherein the epoxy-functional (meth)acrylic monomeric unit constitutes from about 1 wt. % to about 20 wt. % of the copolymer.
10. The polymer composition of claim 1 , wherein the epoxy-functionalized olefin copolymer contains a (meth)acrylic monomeric unit that is not epoxy-functional.
11. The polymer composition of claim 1 , wherein the epoxy-functionalized olefin copolymer exhibits a melt flow rate of from about 1 to about 30 grams per 10 minutes, as determined in accordance with ASTM D1238-13 at a load of 2.16 kg and temperature of 190° C.
12. The polymer composition of claim 1 , wherein the epoxy-functionalized olefin polymer is poly(ethylene-co-butylacrylate-co-glycidyl methacrylate).
13. The polymer composition of claim 1 , further comprising an electrically conductive filler.
14. The polymer composition of claim 13 , wherein the electrically conductive filler includes an ionic liquid.
15. The polymer composition of claim 1 , wherein the composition contains no more than about 10 wt. % of fibrous fillers.
16. The polymer composition of claim 1 , wherein the composition exhibits a Charpy notched impact strength of about 6 kJ/m2 or more, as determined in accordance with ISO Test No. 179-1:2010 at 23° C.
17. The polymer composition of claim 1 , wherein the composition exhibits a dimensional stability of about 6 or less as determined in accordance with ISO 294-4:2001 using a Type D2 specimen.
18. A molded part comprising the polymer composition of claim 1 .
19. A camera module comprising the molded part of claim 18 .
20. The camera module of claim 19 , wherein the camera module comprises a generally planar base on which is mounted a carrier assembly, wherein the base, carrier assembly, or both contain the molded part.
21. A method for joining the molded part of claim 18 to an additional component, wherein the method comprises:
forming receiving holes in the molded part and the component;
inserting heat stakes into the holes; and
subjecting the heat stakes to heat and pressure to thereby join the molded part to the component.
22. A molded part for a camera module, wherein the molded part comprises a polymer composition that includes a liquid crystalline polymer, the composition exhibiting a tensile elongation at break of about 3.5% or more as determined in accordance with ISO Test No. 527:2012 at 23° C., a Charpy notched impact strength of about 6 kJ/m2 or more as determined in accordance with ISO Test No. 179-1:2010 at 23° C., and a dimensional stability of about 6 or less as determined in accordance with ISO 294-4:2001 using a Type D2 specimen.
23. The molded part of claim 22 , wherein the polymer composition comprises an inorganic particulate material having a hardness value of about 2.5 or more based on the Mohs hardness scale.
24. The molded part of claim 23 , wherein the inorganic particulate material has a median size of from about 0.1 to about 35 micrometers.
25. The molded part of claim 22 , wherein the polymer composition comprises an epoxy-functionalized olefin copolymer.