Pennzoil
41Patents
0Active
41Granted
37Portfolio score
Filing activity: Apr 19, 1971 → Dec 15, 2000
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US4501825A | Tire sealer and inflator | Emerging Cross-Sectional Technologies | 50 | Expired |
| USD289376S | Bottle or similar article | General | 47 | Expired |
| US4613446A | Gelled detergent composition and cleaning pads containing same | Chemistry; Metallurgy | 43 | Expired |
| US4303610A | Test kit for field analysis of plant tissue magnesium and calcium | Performing Operations; Transporting | 24 | Expired |
| US4284173A | Motor vehicle lubricating facility | Emerging Cross-Sectional Technologies | 22 | Expired |
| US3998935A | Manufacture of potassium sulfate | Chemistry; Metallurgy | 22 | Expired |
| US4672545A | Method and apparatus for synthesizing three dimensional seismic data | Physics | 21 | Expired |
| US4045543A | Production of potassium sulfate and hydrogen chloride | Chemistry; Metallurgy | 21 | Expired |
| US4670171A | Surface cleaner composition | Chemistry; Metallurgy | 20 | Expired |
| US4670500A | Surface coating composition | Chemistry; Metallurgy | 19 | Expired |
| US4371512A | Production of alkali metal sulfates | Chemistry; Metallurgy | 15 | Expired |
| US3956464A | Preparation of phosphates | Chemistry; Metallurgy | 15 | Expired |
| US4648263A | Support and centering attachments for sensitive viscometers | Physics | 14 | Expired |
| US4866659A | Method for selection of mining and drilling sites using synthesized three dimensional seismic data | Physics | 14 | Expired |
| US4268492A | Process for production of potassium sulfate and hydrochloric acid | Chemistry; Metallurgy | 13 | Expired |
| US4623447A | Breaking middle phase emulsions | Chemistry; Metallurgy | 10 | Expired |
| US4160657A | Preparation of monocalcium phosphate and phosphoric acid | Emerging Cross-Sectional Technologies | 10 | Expired |
| US4049893A | Hydrogenated waxy olefin and process of making same | Emerging Cross-Sectional Technologies | 8 | Expired |
| US4055626A | Method of producing fluoride-free phosphoric acid | Chemistry; Metallurgy | 8 | Expired |
| US4222990A | Production of fluoride-free phosphates | Chemistry; Metallurgy | 8 | Expired |
| US4086322A | Production of fluoride-free phosphates | Chemistry; Metallurgy | 8 | Expired |
| US4397425A | Grinding apparatus | Performing Operations; Transporting | 7 | Expired |
| US4060586A | Recovery of fluorides from gypsum | Chemistry; Metallurgy | 7 | Expired |
| US4387167A | Sulfur-based adducts and compositions | Chemistry; Metallurgy | 7 | Expired |
| US4158558A | Potassium polyphosphate fertilizers | Emerging Cross-Sectional Technologies | 6 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.