July 31, 2023

SEKISUI KASEI CO., LTD. (Head Office: 2-4-4 Nishi-tenma, Kita-ku, Osaka, Japan; President: Masato Kashiwabara),
working together with a research team including Prof. Dr. Hideto Minami in Department of Chemical Science andEngineering at Kobe University, has discovered the world s first ever method for mass producing hollow microparticles
with polyimide shells and has developed "TECHPOLYMER Polyimide Hollow Microparticle" commercial production
technology.

SEKISUI KASEI Develops TECHPOLYMER Polyimide Hollow Microparticles,
the World s First Mass-Producible Polyimide Hollow Microparticles
TMJoint Research Conducted with a Team Including Prof. Dr. Hideto Minami in
Department of Chemical Science and Engineering at Kobe University

1. Background

Polyimide is highly heat resistant and offers exceptional mechanical strength, chemical stability, and insulation
performance. It is applied in a wide range of fields such as electrical and electronic materials and aerospace materials.
Polyimide hollow microparticles with an air layer inside, so they are good insulation, lightweight, have low density, andhave low refractive indexes. For 5G (5th Generation Mobile Communication System), whose strengths are high capacities,
low delay, and multipoint connectivity, there are high hopes for polyimide hollow microparticles as heat resistant, lowdielectric material that can be used in high speed transmission channels to help prevent transmission loss.
However, due to the fact that polyimide is highly heat resistant, it is difficult to process into fine particles, and there
have been almost no reports of successfully creating hollow polyimide particles in the past.

2. Details
TECHPOLYMER is a polymer microparticle made using proprietary polymerization technology and is used in a varietyof applications such as LCD display diffusion material, an additive in cosmetics, and to produce a matte finish inpaints.
SEKISUI KASEI is already selling TECHPOLYMER NH*1, acrylic-based hollow microparticles, but through joint researchwith a team including Prof. Dr. Hideto Minami in Department of Chemical Science and Engineering at Kobe University,
it has recently discovered, for the first time ever* 2, a technique for mass producing hollow microparticles withpolyimide shells, and has developed polyimide hollow microparticles with exceptional insulation performance and heat
resistance.

Features
Spherical microparticles made of polyimide and havehollow structures.

Electron microscope photograph of
Polyimide Hollow Microparticle

Highly heat resistant and chemical stability, and havesuperb mechanical properties.
Lightweight and excellent insulation from interior
hollow structure.
Particle

5% mass reduction temperature

Polyimide hollow microparticles

422℃

Cross-linked PMMA microparticles

270℃

10.0μmAppearance

10.0μmCross-section

3. Future Development

SEKISUI KASEI is switching to businesses that solve environmental and social issues. We will continue to proactively
engage in unprecedented open innovation and rapidly put research and development findings to practical use tocreate new value that illuminates a brighter future for the global environment and society.
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Nanosized polymer particles with a hallow interior.
This has been presented at the 72nd International Polymer Colloids Group Conference, held from June 18 to 23, 2023.

This news release has been distributed to the Chemical Industry Press Club and 21 industry papers.
Similar materials have been distributed by Kobe University to the Hyogo Prefecture Board of Education Press Club, the Kobe Commercial Broadcasting
Press Club, and the Osaka Science and University Press Club.

END