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Diafoil Company, Ltd.

USPTO Granted Patents = 59

Trademarks = 2

Forward Citations = 782

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53 inventors (with patents filed for the assignee):

Shigeo Utsumi (25 out of 30 patents)

Seiji Sakamoto (11 out of 18 patents)

Yujiro Fukuda (9 out of 12 patents)

4. Kichinojo Tomitaka (6 out of 6 patents)

5. Naohiro Takeda (6 out of 8 patents)

6. Yoshinori Sato (5 out of 6 patents)

7. Kazuo Endo (5 out of 17 patents)

8. Yuzo Otani (5 out of 7 patents)

9. Tomoyuki Kotani (5 out of 10 patents)

10. Yoshio Meguro (5 out of 6 patents)

11. Narihiro Masuda (4 out of 10 patents)

12. Nariaki Okajima (4 out of 5 patents)

13. Satoshi Otonari (4 out of 6 patents)

14. Chikakazu Kawaguchi (4 out of 9 patents)

15. Toshifumi Takisawa (4 out of 7 patents)

Core Competencies:

Polyester Film

Magnetic Recording Media

Capacitor Elements

Biaxially Oriented Film

Laminating Material

Heat-Resistant Film

High Density Recording

Electrical Insulating Material

Shrinkable Film

Thermal Transfer Material

Polyethylene Naphthalate Film

Polyphenylene Sulfide Film

59 patents: Sort by Forward Citations

1. 5581435 - Polyester film capacitor element (1996-12-03),

2. 5385768 - Electrically conductive film (1995-01-31),

3. 5212006 - High density magnetic recording medium (1993-05-18),

4. 5188891 - Magnetic recording medium comprising a polyester film substrate, a (1993-02-23),

5. 5164439 - Polyester film for magnetic recording media (1992-11-17),

6. 5153302 - Polyester film for capacitor (1992-10-06),

7. 5145746 - Laminating material for safety glass (1992-09-08),

8. 5106681 - Polyester films, magnetic recording media and film capacitors produced (1992-04-21),

9. 5100719 - Biaxially oriented polyester film containing multilayered cross-linked (1992-03-31),

10. 5096773 - Biaxially oriented polyester film (1992-03-17),

11. 5095332 - Data processing apparatus provided in copying machine (1992-03-10),

12. 5093064 - Low-shrinkage polyester film and preparation thereof (1992-03-03),

13. 5087526 - Biaxially oriented polyester film for use in floppy disc (1992-02-11),

14. 5082730 - Stretched polyester film having an antistatic coating comprising a (1992-01-21),

15. 5071690 - Moldable biaxially stretched polyester film (1991-12-10),

Company Overview

Diafoil Company, Ltd., based in Tokyo, specializes in advanced polyester film technology. The company focuses on the development and manufacturing of high-performance polyester films used in various applications, including magnetic recording media and capacitor elements. Their expertise extends to producing biaxially oriented films, laminating materials, and heat-resistant films, which are essential in high-density recording and electrical insulation. Diafoil's innovations contribute significantly to industries requiring reliable and durable film solutions.

Profile summary synthesized from public USPTO records and patent filings.

Company Badge

USPTO Data Jan 1 1976 - Oct 20 2026

59 Patents

#735 in Tokyo

#1,557 in Japan

#12,247 in the World

Diafoil Company, Ltd.

Forward Citations = 782

53 inventors:

Shigeo Utsumi (25 out of 30 patents)

Seiji Sakamoto (11 out of 18 patents)

Yujiro Fukuda (9 out of 12 patents)

4. Kichinojo Tomitaka (6 out of 6 patents)

5. Naohiro Takeda (6 out of 8 patents)

IDiyas Innovation Intelligence. (2026). Company Patent Portfolio: Diafoil Company, Ltd.. Retrieved from https://idiyas.com/company/diafoil-company

Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile

Data Sources: USPTO Patent Grant XML, Patent Center, EPO & CIPO • Normalized by IDiyas Innovation Graph. Methodology & provenance architecturePlease report any incorrect information to [email protected]

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