History

  • March 1953

    Showa Sekiyu Co., Ltd., (currently Idemitsu Kosan Co.) is established as a subsidiary of Showa Sekiyu Co., Ltd.

  • April 1955

    Manufacturing and sales of pore filling materials and oil-based caulking materials

  • September 1960

    The Tokyo Plant was constructed in Ariake-cho, Koto-ku, Fukagawa for the production of asphalt and concrete

  • April 1968

    Merged with Niigata Asphalt Industry Co., Ltd., and company name was changed to Showa Sekiyu Asphalt Co., Ltd.
    Manufacturing and sales of asphalt waterproofing materials

  • September 1968

    Tokyo Plant relocated to Sunamachi Plant

  • April 1969

    Headquarters relocated to Minami-Oi, Shinagawa-ku, Tokyo. Research laboratory combined with Tokyo Plant
    Started production of sealing materials for construction and waterproofing materials for coating film

  • January 1973

    Sales launch of Toughness Sheets

  • January 1985

    Company name changed to Shosekikako Co., Ltd.

  • December 1985

    Headquarters and Tokyo Branch relocated to 1-11-2 Yoyogi, Shibuya-ku, Tokyo

  • October 1987

    Complete renovation of mixing plant at Sunamachi Plant in Tokyo

  • June 1989

    Sales launch of Highness Sheets

  • October 1989

    Yokkaichi Plant constructed

  • April 1992

    Yokkaichi Plant obtained JIS mark labeling permit (JIS A-6022)
    Sales launch of Rapiness Sheets

  • November 1992

    Recycling plant completed at Sunamachi Plant

  • September 1995

    Pavedrain patented

  • April 2000

    Sales launch of FL Coa

  • May 2001

    ISO certification (9001)
    Japan Kensa QA Co., Ltd. JICQ A-0965

  • September 2006

    Sales launch of Highness Sheet SW-S

  • January 2008

    Sales launch of SBS Milia Series

  • December 2009

    Yokkaichi Plant obtained JIS A-6013 certification

  • March 2010

    Headquarters and Tokyo Branch relocated to 2-3-2 Daiba, Minato-ku, Tokyo

  • November 2014

    Sales launch of Cross Armor

  • October 2016

    Sales launch of Toughness Fine

  • November 2017

    Sunamachi Ascon Co., Ltd. is established

  • January 2018

    Overseas expansion begins

  • April 2018

    Spin off and selling of mixed materials business

  • March 2021

    Headquarters and Tokyo Branch relocated to 3-1-1 Marunouchi, Chiyoda-ku, Tokyo

  • April 2021

    New Functional Paving Materials Manufacturing Department is established following merger with Rekisei Kagaku Co. Ltd.

  • July 2021

    Idemitsu Kosan Co., Ltd.’s Mie Plant transferred to Shosekikako Co., Ltd.
    Renamed Shosekikako Co., Ltd. Mie Plant and placed under the control of Functional Paving Materials Manufacturing Department

  • May 2024

    Headquarters and Tokyo Branch relocated to 1-13-21 Minamiikebukuro, Toshima-ku, Tokyo