Method of making a thermoplastic composition containing an antistatic agent

1. A method of preparing a thermoplastic composition, comprising:

preparing a phosphonium sulfonate salt of generic formula (1)

wherein each X is independently a halogen or hydrogen, provided that the molar ratio of halogen to hydrogen is greater than about 0.90; p is 0 or 1 and q and r are integers of 0 to about 7 provided that q+r is less than 8 and that if p is not zero then r is greater than zero; and each R is the same or different hydrocarbon radical containing 1 to about 18 carbon atoms; wherein preparing the phosphonium sulfonate salt comprises

combining in an aqueous medium

sodium hydroxide and/or lithium hydroxide;

a compound of the generic formula (4)

wherein X, q, p, and r are as defined above; and

a compound of the generic formula (3)

(R) 4 P-Z  (3)

wherein Z is a halogen and R is as defined above; and

separating the phosphonium sulfonate of formula (1) from the aqueous medium; and

combining the phosphonium sulfonate salt with a thermoplastic resin.

2. The method of claim 1 wherein the molar ratio of the compound in formula (4) to the compound in formula (3) is of about 1:2.01 to about 1:3.

3. The method of claim 1 wherein the sulfonate is perfluoromethane sulfonate, perfluorobutane sulfonate, perfluorohexane sulfonate, perfiuoroheptane sulfonate, perfluorooctane sulfonate, or a combination comprising at least one of the foregoing organic sulfonate anions; and wherein the phosphonium is tetrabutylphosphonium.

4. The method of claim 1 wherein the lithium and/or sodium hydroxide are added to the compound of formula (4) before the compound of formula (3).

5. The method of claim 4 wherein the product of the addition of the lithium hydroxide and/or sodium hydroxide to the compound of formula (4) is an alkali sulfonate salt of formula (2)

wherein M is Li or Na, and X, q, p, and r are as defined for formula (1).

6. The method of claim 5 , further comprising isolating a salt of formula (2)

wherein M is Li or Na, and X, q, p, and r are as defined for formula (1); wherein isolating the salt of formula (2) is conducted prior to addition of the compound of formula (3).

7. The method of claim 1 , wherein the thermoplastic resin is selected from the group consisting of polycarbonate, polyetherimide, polyester, polyphenylene ether/polystyrene blends, polyamides, polyketones, acrylonitrile-butadiene-styrenes, and combinations thereof.

8. The method of claim 1 , wherein the thermoplastic resin is polycarbonate.

9. The method of claim 1 , wherein combining the phosphonium sulfonate salt with the thermoplastic resin comprises using a phosphonium sulfonate salt amount of 0.01 to 10 weight percent, based on the weight of the thermoplastic resin.

10. A method of preparing a polycarbonate composition, comprising:

preparing tetrabutylphosphonium perfluorobutane sulfonate by a method comprising

combining in an aqueous medium

lithium hydroxide,

perfluorobutane sulfonyl fluoride, and

a tetrabutylphosphonium halide; and

separating tetrabutyiphosphonium perfluorobutane sulfonate from the aqueous medium; and

combining the tetrabutylphosphonium perfluorobutane sulfonate with a polycarbonate.