Straw contains a large amount of silica (wax layer), which is a natural waterproof substance that plays a moisture-proof and waterproof role similar to paraffin additives in moisture-proof boards. MDI reacts with the water and hydrophilic hydroxyl groups in the orange stem during the board making process, consuming and shielding the hydrophilic groups, generating polymer compounds with strong water resistance. Therefore, the 2-hour swelling rate of Wanhua Hexiang board is only 1.4%, which is better than the national standard for wooden particle board.
