Low fluoride thermoplastic composition, method of manufacture and product made therefrom
View Patent ↗A thermoplastic composition that includes a base polymer, a fluoropolymer, and a fluoride scavenger having suitable fluoride levels such that use in the electronics industry is appropriate. An extrusion method may be used for making the thermoplastic composition. The compositions may then be used to form a molded article. The composition has lower fluoride levels as compared to thermoplastic compositions without the fluoride scavenger making it suitable for use in electronic applications, as well as medical or food or beverage applications where fluoride ions are a concern.
1. A thermoplastic composition, comprising:
a base polymer; wherein said base polymer is polyimide, polyphenylene sulfide, polyphenylene ether, polyethersulfone, polysulfone, polyetheretherketone, polycarbonate, polyphenylene oxide, polyester, polyamide, polystyrene, mixtures, copolymers, reaction products, or blends comprising at least one of the foregoing polymers
an irradiated fluoropolymer; wherein the fluoropolymer is present in the range from 3 to 50% by weight of the thermoplastic composition; and
a fluoride scavenger; wherein the fluoride scavenger is an organic calcium salt, calcium oxide, minerals with calcium oxide; or a mixture comprising at least one of the foregoing fluoride scavengers; wherein the fluoride scavenger is effective to produce a fluoride level of below 40 micrograms per gram of the thermoplastic composition; and wherein said composition has a lower fluoride ion level relative to a composition consisting of the base polymer and the fluoropolymer.
2. The composition of claim 1 wherein the base polymer is polyetherimide.
3. The composition of claim 1 wherein the base polymer is a polyphenylene ether/polystyrene blend.
4. The composition of claim 1 wherein the base polymer is polycarbonate.
5. The composition of claim 1 wherein the fluoropolymer is polytetrafluoroethylene (PTFE).
6. The composition of claim 1 wherein the organic calcium salt is calcium stearate.
7. The composition of claim 1 wherein the base polymer is present in the range from 97 to 50% by weight exclusive of any fillers.
8. The composition of claim 1 wherein the fluoride scavenger is present in the range from 0.01 to 5% by weight of the thermoplastic composition.
9. The composition of claim 1 wherein the fluoride level is below 10 micrograms per gram of the thermoplastic composition.
10. An article comprising the composition of claim 1 .
11. A method comprising:
extruding the thermoplastic composition of claim 1 ;
quenching the composition in a deionized water bath; and
pelletizing the composition.
12. The method of claim 11 further comprising the steps of:
drying the pellets; and
molding the pellets into a shaped article.
13. The method of claim 12 wherein the fluoropolymer is polytetrafluoroethylene (PTFE).
14. The method of claim 12 wherein the base polymer is present in the range from 97 to 50% by weight exclusive of any fillers, the fluoropolymer is present in the range from 3 to 50% by weight, and the fluoride scavenger is present in the range from 0.01 to 5% by weight.
15. The method of claim 12 wherein the fluoride level is below 40 ug/g.