News Release
November 30, 2023
Proterial, Ltd.

D2MateriTM, a Materials Informatics Platform,
Applied to Wire Coating Material Development
Proterial, Ltd. (hereinafter referred to as "Proterial") has successfully applied D2MateriTM (hereinafterreferred to as "D2Materi"), its proprietary Materials Informatics (hereinafter referred to as "MI") platform, tothe development of materials for wire coating materials. We have also used D2Materi in developing coatingmaterials for wires used in actual rolling stock, and have verified that it can greatly shorten the time required
to develop formulations of coating materials.
1. Background
MI is a technology for improving the efficiency of materials development with the use of informatics (informationscience) such as statistical analysis and machine learning. We expect that the use of MI will enable us to predict optimal
combinations of materials with a high degree of accuracy. Based on microstructure and composition control
technologies as well as academic knowledge that we have accumulated to date at Proterial, our materials informatics
platform, D2Materi, enables designers to carry out designs by deriving correlations between, and laws andcharacteristics associated with performance and composition/processes.
As for electric wires, one of our main products, the characteristics of their coating material are a major factor thatdetermines their performance. Characteristics, such as good insulation despite thinness, suppleness and durability, areachieved through various combinations of different polymers*1 and fillers*2. In the past, development relied on trialand error with a large number of combinations and numerous tests. To improve development efficiency, we enabled
D2Materi to handle complex conditions that come with combining polymers (which are organic) with fillers (whichare inorganic) in numerous combinations, and eventually applied D2Materi to the development of coating materials
for wires used in rolling stock, which requires a high level of reliability.

Predicted elongation [%]2. Overview(1) Application of D2Materi to wire coating materials
By applying D2Materi in the development of wire coatingmaterials, Proterial is now able to predict with high accuracy
the formulation of polymers and fillers that deliver target
characteristics.
In applying D2Materi to wire coating materials, we defined
the weight of polymers and fillers as the explanatory
variables*3, and the required characteristics as the target
variables*4, and have also added data predicted to have an affecton material characteristics, such as parameters that correspondto the interfacial strength*5 of polymers and fillers, to build aunique model for predicting physical properties. The physicalproperties predicted using this model were found to be highly
accurate, with an error rate of about 10% vis-a-vis actual physicalproperties.
Toyosu Prime Square, 5-6-36 Toyosu, Koto-ku, Tokyo 135-0061, Japanwww.proterial.com/e/1/3

Average prediction error rate when
not using interfacial strength: 10.1%

Average prediction error rate whenusing interfacial strength: 8.9%

Actual elongation [%]Predicted and measured elongation
characteristics
This shows that the error rate vis-a-vis actual
physical properties is about 10%. We have verified
that by adding a parameter corresponding tointerfacial strength, the average prediction error
rate improved from 10.1% to 8.9%.

(2) Using D2Materi to develop wire coating materials for wires used in rolling stock
In the development of coating materials for wires used in actual rolling stock, formulations being considered
consisting of exhaustive combinations of different polymers and fillers were entered in D2Materi to obtain thepredicted values of different physical properties. After selecting 20 types of formulations with excellent predicted
properties, prototypes were made and verification experiments were conducted, which confirmed that good properties
could be obtained. While it previously took about a year to obtain the optimal formulation, development using
D2Materi was completed in less than three months, greatly improving the speed of formulation development.
Going forward, Proterial will accelerate development by applying D2Materi to advanced materials other thanwire coating materials, and contribute to solving social issues such as fuel efficiency, energy conservation, anddecarbonization.
We are scheduled to present this information at the 32nd Polymer Materials Forum hosted by the Society ofPolymer Science, Japan, to be held at the Nagoya Congress Center from November 30 to December 1, 2023.

*1 Polymer: A high-molecular weight compound formed by combining a number of monomers*2 Filler: Material added to resin for the purpose of improving its physical and other properties, etc.
*3 Explanatory variable: Data that influences the desired value*4 Target variable: Target data to be predicted*5 Interfacial strength: Strength of the interface between materials when dissimilar materials are composited[Media inquiries] Corporate Communications Dept., Proterial
https://www.cntct.proterial.com/contact/publish/inquiry_eng?g=01&c=001-01

D2Materi is a trademark of Proterial, Ltd.

Toyosu Prime Square, 5-6-36 Toyosu, Koto-ku, Tokyo 135-0061, Japanwww.proterial.com/e/2/3

About PROTERIAL“Proterial” reflects the essence of our corporate philosophy, which consists of three elements: Mission: “Make the best quality
available to everyone;” Vision: “Leading sustainability by high performance;” and Values: “Unfaltering integrity” and “Unitedby respect.” It combines “pro-” with the word “material.”“Pro-” represents our “three pros”:
Professional — work that exceeds expectations
Progressive — a spirit that keeps challenging
Proactive —an enterprising attitude“Material” refers to the high-performance materials that our original technologies produce and underpinned by the three pros.
With our focus on solving customer issues and bringing new levels of value, we promise to contribute to the realization of asustainable society through the products and services that embody our philosophy.

Proterial, Ltd. — Company Overview
Established: April 1956
Head office: Toyosu Prime Square, 5-6-36 Toyosu, Koto-ku, Tokyo 135-0061, Japan
Capital: 310 million yen (as of March 31, 2023)
Representative: Representative Director, Chairman, President and Chief Executive Officer (CEO)Sean M. Stack
Sales revenue: 1,118.9 billion yen (Term ended March 2023)
History: 1910: Founded as Tobata Foundry Co.
1937: Merged with Hitachi, Ltd.
1956: Established separately as Hitachi Metals Industries, Ltd.
2023: Company separated from the Hitachi Group, and renamed from Hitachi Metals, Ltd. toProterial, Ltd.

Toyosu Prime Square, 5-6-36 Toyosu, Koto-ku, Tokyo 135-0061, Japanwww.proterial.com/e/3/3