{
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  "company_name": "トクヤマ",
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  "updated": "2026-09-05",
  "license": "© 2026 Yutaka Sugiura. All rights reserved.",
  "attribution": "The社史 (the-shashi.com) — https://the-shashi.com/tse/4043/",
  "source": {
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      "有価証券報告書",
      "トクヤマ ニュースリリース"
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    "extraction": "有価証券報告書の沿革を基礎に、社史・報道で補完",
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      "date": "1918/2",
      "importance": 1,
      "event": "日本曹達工業として発足",
      "source": "有価証券報告書"
    },
    {
      "date": "1936/1",
      "importance": 1,
      "event": "商号を徳山曹達に変更",
      "source": "有価証券報告書"
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    {
      "date": "1937/5",
      "importance": 1,
      "event": "東京営業所を開設",
      "source": "有価証券報告書"
    },
    {
      "date": "1938/3",
      "importance": 2,
      "event": "徳山工場で湿式法ポルトランドセメント製造を開始",
      "source": "有価証券報告書"
    },
    {
      "date": "1949/5",
      "importance": 1,
      "event": "東京証券取引所に上場",
      "source": "有価証券報告書"
    },
    {
      "date": "1952/3",
      "importance": 1,
      "event": "徳山工場で電解苛性ソーダの製造を開始",
      "source": "有価証券報告書"
    },
    {
      "date": "1960/12",
      "importance": 1,
      "event": "南陽工場を新設",
      "source": "有価証券報告書"
    },
    {
      "date": "1964/7",
      "importance": 1,
      "event": "プロピレンオキサイド工場を新設",
      "source": null
    },
    {
      "date": "1966/9",
      "importance": 2,
      "event": "サンアロー化学を設立し塩化ビニール製造を開始",
      "source": null
    },
    {
      "date": "1967/3",
      "importance": 1,
      "event": "イオン交換膜製造工場を新設",
      "source": null
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    {
      "date": "1967/6",
      "importance": 1,
      "event": "東工場を新設",
      "source": "有価証券報告書"
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    {
      "date": "1970/3",
      "importance": 1,
      "event": "東工場でポリプロピレンの製造を開始",
      "source": "有価証券報告書"
    },
    {
      "date": "1972/7",
      "importance": 1,
      "event": "東工場でイソプロピルアルコールの製造を開始",
      "source": "有価証券報告書"
    },
    {
      "date": "1972/11",
      "importance": 1,
      "event": "技術研究所を新設",
      "source": "有価証券報告書"
    },
    {
      "date": "1978/3",
      "importance": 1,
      "event": "トーワ技研を設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1982/8",
      "importance": 1,
      "event": "プラスチックレンズ材料を発売",
      "source": null
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    {
      "date": "1983/8",
      "importance": 2,
      "event": "電子工業用高純度溶剤（IPA・塩化メチレン）を発売",
      "source": null
    },
    {
      "date": "1984/7",
      "importance": 3,
      "event": "東工場で多結晶シリコンの製造を開始",
      "source": "有価証券報告書",
      "link": "/tse/4043/decisions/polysilicon-entry-1984/"
    },
    {
      "date": "1985/4",
      "importance": 1,
      "event": "鹿島工場を新設",
      "source": "有価証券報告書"
    },
    {
      "date": "1989/7",
      "importance": 2,
      "event": "ゼネラル・セラミックス社を買収",
      "source": null
    },
    {
      "date": "1994/4",
      "importance": 1,
      "event": "商号をトクヤマに変更",
      "source": "有価証券報告書"
    },
    {
      "date": "1994/4",
      "importance": 1,
      "event": "エイアンドティーを設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1995/7",
      "importance": 1,
      "event": "新第一塩ビを設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1996/6",
      "importance": 1,
      "event": "Tokuyama Electronic Chemicals Pte Ltdを設立",
      "source": "有価証券報告書"
    },
    {
      "date": "1996/8",
      "importance": 1,
      "event": "台湾徳亞瑪を設立",
      "source": "有価証券報告書"
    },
    {
      "date": "2005/9",
      "importance": 1,
      "event": "徳山化工（浙江）有限公司を設立",
      "source": "有価証券報告書"
    },
    {
      "date": "2007/2",
      "importance": 1,
      "event": "TDパワーマテリアルを設立",
      "source": "有価証券報告書"
    },
    {
      "date": "2008/1",
      "importance": 1,
      "event": "Tokuyama Korea Co., Ltd.を設立",
      "source": "有価証券報告書"
    },
    {
      "date": "2009/3",
      "importance": 2,
      "event": "初の純損失を計上",
      "source": "有価証券報告書"
    },
    {
      "date": "2009/8",
      "importance": 2,
      "event": "Tokuyama Malaysia Sdn. Bhd.を設立",
      "source": "有価証券報告書"
    },
    {
      "date": "2013/3",
      "importance": 1,
      "event": "純損失379億円を計上",
      "source": "有価証券報告書"
    },
    {
      "date": "2015/6",
      "importance": 1,
      "event": "横田浩が代表取締役社長執行役員に就任",
      "source": "有価証券報告書"
    },
    {
      "date": "2016/3",
      "importance": 2,
      "event": "純損失1006億円を計上",
      "source": "有価証券報告書"
    },
    {
      "date": "2017/5",
      "importance": 3,
      "event": "Tokuyama Malaysia Sdn. Bhd.の全株式を譲渡",
      "source": "有価証券報告書",
      "link": "/tse/4043/decisions/malaysia-silicon-2017/"
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    {
      "date": "2018/7",
      "importance": 1,
      "event": "徳山海陸運送の全株式を取得",
      "source": "有価証券報告書"
    },
    {
      "date": "2023/5",
      "importance": 3,
      "event": "OCIと半導体用多結晶シリコン事業の協業に係る覚書を締結",
      "source": "トクヤマ ニュースリリース",
      "link": "/tse/4043/decisions/silicon-overseas-return-2023/"
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    {
      "date": "2024/4",
      "importance": 2,
      "event": "セメントキルン1系列を停止",
      "source": "トクヤマ ニュースリリース"
    },
    {
      "date": "2025/7",
      "importance": 1,
      "event": "合弁会社OCI Tokuyama Semiconductor Materials Sdn. Bhd.を設立",
      "source": "トクヤマ ニュースリリース"
    },
    {
      "date": "2026/3",
      "importance": 3,
      "event": "セメント・固化材の国内販売事業と子会社2社を太平洋セメントへ譲渡すると決定",
      "source": "トクヤマ ニュースリリース",
      "link": "/tse/4043/decisions/cement-exit-2026/"
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}