Challenge for blow molding of wood and paper

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K21331
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Mie University
• Principal Investigator: Nonaka Hiroshi 三重大学, 生物資源学研究科, 教授 (90422881)
• Project Period (FY): 2020-07-30 – 2024-03-31
• Keywords: バイオマス / 木 / プラスチック代替 / ボトル / 中空成形 / セルロース誘導体 / PVA

Outline of Final Research Achievements

The wood meal-HPMC-water mixture that we had developed as a material for extrusion molding of wood meal could be changed to have fluidity suitable for injection molding by adjusting the moisture content. However, it was difficult to inflate it with air pressure by adjusting the moisture content alone, so new materials were considered for addition. As a result, it was found that adding PVA and borax to wood meal, HPMC, and water results in a hydrogel, which is a highly expandable material that can be applied to blow molding. The gel was expanded without heating in a bottle split mold, and then dried, leading to the successful production of a bottle prototype. The prototype is 85% bio-derived (wood meal + HPMC), with the remainder being biodegradable PVA and borax.

Free Research Field

バイオマス科学

Academic Significance and Societal Importance of the Research Achievements

パリ協定が正式に採択され，人間活動による温室効果ガスの排出量を実質的にはゼロにしていく長期目標が定められている。また海洋プラスチックごみ問題，マイクロプラスチック問題が深刻化しており，紙製品などに代替する動きも加速しているが，木や紙は熱可塑性がなく熱分解するゆえ成形ができない。本研究は，木や紙を押出成形のみならず，ブロー成形（中空成形）する可能性を探索し，バイオマス製品の普及拡大を目指す社会的意義がある。基本的に「硬くて割れる」木質材料から，いかに柔軟で，空気で膨らむ素材を創製するかは挑戦的であり，実際に空圧で膨らむ木質素材を見出した点において学術的にも大きな成果をあげたといえる。