Aromatic polymer composition for use in a camera module
A polymer composition that contains an aromatic polymer in combination with a tribological formulation is provided. The polymer composition may exhibit a low degree of surface friction that minimizes the extent to which a skin layer is peeled off during use of a part containing the composition (e.g., in a camera module). For example, the polymer composition may exhibit a dynamic coefficient of friction of about 1.0 or less and/or a wear depth may be about 500 micrometers or less as determined in accordance with VDA 230-206:2007.
1. A polymer composition comprising at least one thermotropic liquid crystalline polymer and a tribological formulation in an amount from about 1 to about 20 parts by weight per 100 parts by weight of the liquid crystalline polymer, wherein the tribological formulation contains a fluorinated additive and a siloxane polymer having a weight average molecular weight of about 100,000 grams per mole or more, and further wherein the weight ratio of the fluorinated additive to the siloxane polymer is from about 0.5 to about 12.
2. The polymer composition of claim 1 , wherein the liquid crystalline polymer constitutes from about 20 wt. % to about 70 wt. % of the polymer composition and the tribological formulation constitutes from about 1 wt. % to about 30 wt. % of the polymer composition.
3. The polymer composition of claim 1 , wherein the siloxane polymer is present in an amount from about 0.4 to about 10 parts by weight per 100 parts by weight of the liquid crystalline polymer.
4. The polymer composition of claim 1 , wherein the siloxane polymer includes siloxane units in the backbone having the formula:
RrSiO (4-r/2)
wherein R is independently hydrogen or substituted or unsubstituted hydrocarbon radicals and r is 0, 1, 2 or 3.
5. The polymer composition of claim 4 , wherein the siloxane polymer includes alkyl radicals bonded to at least 70 mol % of the Si atoms.
6. The polymer composition of claim 1 , wherein the siloxane polymer includes dimethylpolysiloxane, phenylmethylpolysiloxane, vinylmethylpolysiloxane, trifluoropropylpolysiloxane, or a combination thereof.
7. The polymer composition of claim 1 , wherein the siloxane polymer has a kinematic viscosity of about 10,000 centistokes or more.
8. The polymer composition of claim 1 , wherein the tribological formulation further includes silica particles.
9. The polymer composition of claim 1 , wherein the fluorinated additive is present in an amount of from about 0.1 to about 20 parts by weight per 100 parts by weight of the aromatic polymer.
10. The polymer composition of claim 1 , wherein the fluorinated additive includes a fluoropolymer.
11. The polymer composition of claim 10 , wherein the fluoropolymer includes polytetrafluoroethylene, perfluoroalkylvinyl ether, poly(tetrafluoroethylene-co-perfluoroalkyvinyl ether) fluorinated ethylene-propylene copolymer, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, polychlorotrifluoroethylene, or a combination thereof.
12. The polymer composition of claim 10 , wherein the fluoropolymer is coated onto carrier particles.
13. The polymer composition of claim 12 , wherein the carrier particles include silicate particles.
14. The polymer composition of claim 1 , further comprising an inorganic filler in an amount of from about 10 to about 95 parts by weight per 100 parts by weight of the liquid crystalline polymer.
15. The polymer composition of claim 14 , wherein the inorganic filler contains particles having a hardness value of about 2.5 or more based on the Mohs hardness scale.
16. The polymer composition of claim 15 , wherein the particles include barium sulfate.
17. The polymer composition of claim 1 , further comprising an impact modifier in an amount from about 0.1 to about 20 parts by weight per 100 parts by weight of the liquid crystalline polymer.
18. The polymer composition of claim 17 , wherein the impact modifier includes an epoxy-functionalized olefin copolymer.
19. The polymer composition of claim 1 , further comprising an antistatic filler in an amount from about 0.1 to about 20 parts by weight per 100 parts by weight of the liquid crystalline polymer.
20. The polymer composition of claim 19 , wherein the antistatic filler includes an ionic liquid.
21. The polymer composition of claim 1 , wherein the liquid crystalline polymer contains 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.
22. The polymer composition of claim 1 , wherein the composition exhibits a dynamic coefficient of friction of about 1.0 or less as determined in accordance with VDA 230-206:2007.
23. The polymer composition of claim 1 , wherein the composition exhibits a wear depth of about 500 micrometers or less as determined in accordance with VDA 230-206:2007.
24. The polymer composition of claim 1 , wherein the composition exhibits a spiral flow length of about 15 millimeters or more as determined in accordance with ASTM D3121-09.
25. A molded part comprising the polymer composition of claim 1 .
26. A camera module comprising the molded part of claim 25 .