| 摘要 |
A packaging material (1) comprises two or more corrugated material strips (2, 3) with high stiffness along the corrugations and high flexibility in the other direction and a corrugated central layer (4) between them consisting of a foamed material based on starch and natural and/or synthetic elastomers. Also claimed is manufacture of the packaging material (1), where two or more material strips are formed between corrugating rolls and then passed through a further pair of corrugating rolls where a layer (4) of the foamable starch based material containing water is extruded between both layers (2, 3). The temperature, water content and consistency of the foamable material layer and the temperature and speed of the corrugating rolls are varied to ensure the material (4) foams when leaving the rolls to fill the space between the corrugated strips (2, 3). Finally paper or thin card strips (8, 9) are bonded (16) onto the outer peaks of the corrugations to complete the packaging material (1). |
