Multi-patent compare
Up to four patents, side by side.
Compare citations, claim scope, expiry, litigation, an estimated value range, and an A–F strength grade across multiple patents in one view. Use it for portfolio analysis, competitor research, or FTO scoping.
US 2130523 How Wallace Carothers Invented NylonEI Du Pont de Nemours and Co | US 3733309 How Plastic Soda Bottles Are Made Stronger Using Stretched MoleculesEI Du Pont de Nemours and Co | US 3819587 The Molecular Structure of Kevlar High-Strength FiberEI Du Pont de Nemours and Co | US 3671542 How Stephanie Kwolek Invented the Liquid Crystal Solution for KevlarEI Du Pont de Nemours and Co | |
|---|---|---|---|---|
| Status | expired | expired | expired | expired |
| Filing date | 1935-01-02 | 1970-11-30 | 1971-09-07 | 1969-05-23 |
| Grant date | 1938-09-20 | 1973-05-15 | 1974-06-25 | 1972-06-20 |
| Expires | 1955-09-20 | 1990-11-30 | 1991-09-07 | 1989-06-20 |
| Claims | 0 | 0 | 15 | 1 |
| Forward citations | 299 | 170 | 141 | 132 |
| Backward citations | 0 | 0 | 6 | 7 |
| Litigation | None | None | None | None |
| Estimated value | $24K – $77K | $27K – $86K | $36K – $115K | $86K – $276K |
| Strength grade | D (51/100) | D (51/100) | C (60/100) | D (55/100) |
For spreadsheet portfolio analysis.
Estimated value uses the same heuristic as the Patent Value Estimator. Heuristic only — not a substitute for professional appraisal.