Inventor · Houston, TX, US

John A. Ewen

54Patents
32h-index
15Co-inventors
85Inventor score

Filing activity: Jun 6, 1983 → Jun 28, 2007

Most-cited inventions

PatentTitleAreaCited byStatus
US5324800A Process and catalyst for polyolefin density and molecular weight control Emerging Cross-Sectional Technologies 531 Expired
US4794096A Hafnium metallocene catalyst for the polymerization of olefins Emerging Cross-Sectional Technologies 494 Expired
US4937299A Process and catalyst for producing reactor blend polyolefins Emerging Cross-Sectional Technologies 459 Expired
US4892851A Process and catalyst for producing syndiotactic polyolefins Emerging Cross-Sectional Technologies 346 Expired
US4530914A Process and catalyst for producing polyethylene having a broad molecular weight distribution Emerging Cross-Sectional Technologies 334 Expired
US5387568A Preparation of metallocene catalysts for polymerization of olefins Emerging Cross-Sectional Technologies 184 Expired
US5155080A Process and catalyst for producing syndiotactic polyolefins Emerging Cross-Sectional Technologies 171 Expired
US4935474A Process and catalyst for producing polyethylene having a broad molecular weight distribution Emerging Cross-Sectional Technologies 167 Expired
US5036034A Catalyst for producing hemiisotactic polypropylene Emerging Cross-Sectional Technologies 125 Expired
US4975403A Catalyst systems for producing polyolefins having a broad molecular weight distribution Emerging Cross-Sectional Technologies 110 Expired
US5416228A Process and catalyst for producing isotactic polyolefins Chemistry; Metallurgy 103 Expired
US5225500A Process and catalyst for producing syndiotactic polyolefins Emerging Cross-Sectional Technologies 100 Expired
US6184326A Syndiotactic polypropylene Chemistry; Metallurgy 97 Expired
US4522982A Isotactic-stereoblock polymers of alpha-olefins and process for producing the same Emerging Cross-Sectional Technologies 90 Expired
US4927797A Catalyst system for the polymerization of olefins Emerging Cross-Sectional Technologies 85 Expired
US4767735A Catalyst pretreatment process Emerging Cross-Sectional Technologies 79 Expired
US5663249A Catalyst and process for polymerization of olefins Emerging Cross-Sectional Technologies 73 Expired
US5633394A Catalyst compounds for olefin polymerization Emerging Cross-Sectional Technologies 70 Expired
US5561092A Metallocene catalysts with lewis acids and aluminum alkyls Emerging Cross-Sectional Technologies 69 Expired
US5334677A Process for producing syndiotactic polyolefins Emerging Cross-Sectional Technologies 68 Expired
US6635779B1 Metallocene compounds, process for their preparation and their use in catalytic systems for the polymerization of olefins Emerging Cross-Sectional Technologies 66 Expired
US5459117A Doubly-conformationally locked, stereorigid catalysts for the preparation of tactiospecific polymers Chemistry; Metallurgy 64 Expired
US6444833B1 Metallocene compounds, process for their preparation and their use in catalytic systems for the polymerization of olefins Emerging Cross-Sectional Technologies 57 Expired
US5122583A Efficiency of a pre-polymerized catalyst Emerging Cross-Sectional Technologies 56 Expired
US5066738A Polymerization of olefins with an improved catalyst system using a new electron donor Emerging Cross-Sectional Technologies 56 Expired

Source: USPTO / EPO open patent data. Inventor disambiguation is heuristic; counts are objective bibliographic measures.