Acid sensor

• US 5,023,133 A
• Filed: 02/01/1990
• Issued: 06/11/1991
• Est. Priority Date: 12/12/1986
• Status: Expired due to Term

• Current Assignee: The Lubrizol Corporation (Berkshire Hathaway Incorporated)
• Original Assignee: The Lubrizol Corporation (Berkshire Hathaway Incorporated)
• Inventors: Gapinski, Richard E., Yodice, Richard
• Primary Examiner(s): Foelak, Morton
• Application Number:
  US07/474,236
• Time in Patent Office: 495 Days
• Field of Search: 428/332, 428/339, 428/402, 528/422, 252/500
• US Class Current: 428/332
• CPC Class Codes: G01N 27/126 comprising organic polymers
• CPC Class Codes: G01N 33/2888 Lubricating oil characteristics, e.g. deterioration lubricating properties G01N33/30
• CPC Class Codes: Y10T 428/26 Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension
• CPC Class Codes: Y10T 428/269 including synthetic resin or polymer layer or component
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

The present invention describes devices capable of sensing changes of acidity in a non-aqueous medium. The devices are particularly useful for determining the alkaline reserve in a motor vehicle lubricating oil.

Claims

1. A polymer article comprising a partially protonated polyaniline polymer having a thickness in the range from about 0.1 to 2 mm, wherein the greatest axis of the article is up to about 25 mm.

2. The article of claim 1 in the form of a cylindrical pellet.

3. The article of claim 1 in the form of a disk.

4. The article of claim 3 wherein the disk has a thickness in the range of about 0.4 to about 1.5 mm.

5. The article of claim 1 wherein the polymer has a resistance to the flow of electrons in the range of from about 2.4×

10⁶ to 2.6×

10⁶ ohm/cm measured at 55°

C. in an additive-free oil of lubricating viscosity.

6. A polymer article comprising a solid partially protonated polyaniline polymer in the form of a cylindrical disk having a diameter in the range from 7.5 to 18 mm and a thickness in the range from about 0.1 to 2 mm.

7. The article of claim 6 wherein the article has a thickness in the range from about 0.4 to about 1.5 mm.

8. The article of claim 6 wherein the polymer has resistance to the flow of electrons in the range from about 2.4×

10⁶ to 2.6×

10⁶ ohm/cm measured at 55°

C. in an additive-free oil of lubricating viscosity.

9. The article of claim 6 wherein the article has a resistance to the flow of electrons in the range from about 1.5×

10⁶ to 1.7×

10⁶ ohm/cm measured at 65°

C. in an additive-free oil of lubricating viscosity.

10. A solid partially protonated polyaniline polymer product prepared by:

(A) deprotonating a polyaniline polymer by treating the polymer with a base and

(B) reprotonating the deprotonated polymer obtained as a product of step (A) by treating the deprotonated polymer with an acid.

11. The polymer product of claim 10 wherein the base of (A) is sodium hydroxide, potassium hydroxide, sodium alkoxide, or potassium alkoxide, or a mixture thereof and the acid of (B) is hydrochloric acid.

12. The polymer product of claim 10 wherein step (B) comprises:

(1) dispersing 1% by weight of the polymer obtained from step (A) in water adjusted to a pH of from 2 to 4 measured at a temperature of 25°

C. and

(2) maintaining the polymer-containing water of step (1) at a pH in the range from 2 to 4 measured at a temperature of 25°

C. by adding acid to the polymer-containing water.

13. The polymer product of claim 10 wherein the polymer product has resistance to the flow of electrons in the range from about 2.4×

10⁶ to 2.6×

10⁶ ohm/cm measured at 55°

C. in an additive-free oil of lubricating viscosity.