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For the Inventor, By the Inventor

Hyogo, Japan

Tsutomu Yamato

This inventor holds 10 USPTO granted patents. Top assignee: Daicel Chemical Industries, Ltd.. Active years: 1992-1997.

IDiyas Innovation Intelligence. (2026). Inventor Profile: Tsutomu Yamato. Retrieved from https://idiyas.com/inventor/tsutomu-yamato

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

USPTO Granted Patents = 10

% Patents Active = 100.0

Average Co-Inventor Count = 5.1

ph-index = 4

Forward Citations = 99(Granted Patents)


Location History:

  • Himeji, JP (1992)
  • Hyogo, JP (1994 - 1997)

Company Filing History:

goldMedal10 out of 1,165 
 
Daicel Chemical Industries, Ltd.
 patents

Years Active: 1992-1997

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10 patents (USPTO):Explore Patents
1. 5610262 - Process for producing polycarbonate (1997-03-11),
2. 5548041 - Process for producing polycarbonate (1996-08-20),
3. 5489665 - Process for producing polycarbonate (1996-02-06),
4. 5468836 - Process for the preparation of polycarbonate (1995-11-21),
5. 5434227 - Process for producing polycarbonate (1995-07-18),
6. 5432250 - Process for producing polycarbonate (1995-07-11),
7. 5391690 - Process for producing (co)polycarbonate and (co)polycarbonate composition (1995-02-21),
8. 5387628 - Process for producing (co)polycarbonate and (co)polycarbonate composition (1995-02-07),
9. 5278279 - Process for producing (co)polycarbonate with transesterification (1994-01-11),
10. 5149770 - Preparation of a polycarbonate with electron donative amine compound and (1992-09-22),

Title: Tsutomu Yamato: Innovator in Polycarbonate Production

Introduction

Tsutomu Yamato is a prominent inventor based in Hyogo, Japan. He has made significant contributions to the field of polycarbonate production, holding a total of 10 patents. His innovative approaches have enhanced the efficiency and quality of polycarbonate manufacturing processes.

Latest Patents

One of Tsutomu Yamato's latest patents involves a process for producing polycarbonate through melt polycondensation via transesterification. In this method, a dihydroxy compound and a diester of carbonic acid are subjected to a two-stage reaction. The first stage involves preparing a polycarbonate prepolymer, followed by polycondensation in a residence time ranging from 15 to less than 60 minutes. This process utilizes at least one paddle-type self-cleaning twin-screw extruder, enabling the production of a colorless, transparent polycarbonate with a high molecular weight at an industrial scale.

Another notable patent by Yamato focuses on producing polycarbonate through transesterification using a dihydroxy compound such as 2,2-bis(4-hydroxyphenyl)propane and a diester of carbonic acid like bisphenyl carbonate. This process is conducted in a reactor made of stainless steel, which is treated by electropolishing or acid pickling. The use of specific nitrogen-containing electron-donating compounds as transesterification catalysts further enhances the efficiency of the process.

Career Highlights

Tsutomu Yamato is associated with Daicel Chemical Industries, Ltd., where he has been instrumental in advancing polycarbonate production techniques. His work has not only contributed to the company's success but has also had a lasting impact on the industry.

Collaborations

Throughout his career, Yamato has collaborated with notable colleagues, including Tatsuya Kanno and Yasuhiro Oshino. These partnerships have fostered innovation and have led to the development of cutting-edge technologies in polycarbonate production.

Conclusion

Tsutomu Yamato's contributions to the field of polycarbonate production exemplify his innovative spirit and dedication to advancing manufacturing processes. His patents reflect a commitment to quality and efficiency, making him a significant figure in the industry.

Profile summary based on public USPTO records.
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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