Method for manufacturing formaldehyde-free straw fiber board

Abstract

The invention relates to a method for manufacturing formaldehyde-free straw fiber boards, comprising the following steps: adding NaAc-HAc buffer solution in wheat straw chemime chanical pulp so as to dilute the pulp into wheat straw fiber suspension liquid with mass concentration of 3-10%, stirring the wheat straw fiber suspension liquid fully and uniformly, respectively addingndustrial lignin being 10-50% of i of oven-dry wheat straw pulp and wax emulsion being 1-10% of oven-dry wheat straw pulp, then adding 10U / g to 100U / g laccase to start the reaction, scattering the treated wheat straw fiber by an electric mixer, molding in a fiber molding machine and then removing redundant moisture by pre-pressing, and then forming the fiber board by hot-pressing. According to the method, lignin is selected to replace the traditional binder used in the productions of middle-density fiber board and high-density fiber board, and the formaldehyde diffusion is inexistent due to the fact that the formaldehyde based binder is unused. The method of the invention is reasonable and simple in operation; and with the adoption of the waste materials of crops wheat stalk, straw and the like, the environment pollution can be reduced, the added value of the product can be enhanced, and the high-strength formaldehyde-free environment-friendly fiber boards are manufactured.

Description

technical field [0001] The invention relates to a method for manufacturing a formaldehyde-free fiberboard made from straw. Background technique [0002] In the production process of fiberboard, there are several technical problems in the existing dry-process fiberboard production process: the release of free formaldehyde in the product is too high, it is difficult to meet the environmental protection requirements; after hot pressing, there is a thick pre-cured layer on the board surface that requires sand In addition, it causes waste of materials and power, which is not conducive to the production of medium and thin MDF; the products generally do not have flame retardancy, and the added flame retardants are generally toxic and cannot be reduced, which affects the performance of the product. [0003] US 2006 / 0127659 A1 "Preparation Process of Medium Density Fiberboard" (MDF Press Technology) disclosed by the US patent, CN201998287U "High Flame Retardancy Bamboo Fiberboard" di...

AI Technical Summary

Problems solved by technology

[0002] In the production process of fiberboard, there are several technical problems in the existing dry-process fiberboard production process: the release of free formaldehyde in the product is too high, it is difficult to meet the environmental protection requirements; after hot pressing, there is a thick pre-cured layer on the board surface that requires sand In addition, it causes waste of materials and power, which is not conducive to the production of medium and thin MDF; the products generally do not have flame retardancy, and the added flame retardants are generally toxic and cannot be reduced, which affects the performance of the product

The common disadvantage of these preparation technologies and processes is that the fibers are not treated, and the physical properties of the fiberboards are not improved by using the chemical bonds that the fibers themselves can form. They simply improve the performance of the fiberboards by adding binders. The physical strength, water resistance and environmental protection performance of fiberboard are poor

[0004] US 2011 / 0009530 A1 "Formaldehyde-free Binders for Producing Wood Products" published in US Patent, US 7722712 B2 "Preparation of Formaldehyde-free Binders Based on Wood Fiber" (Formaldehyde-free Binders for Producing Wood Products) published in US Patent -free Adhesives and Lignocellular Composites Made From the Adhesives), CN101791817A "Environmental-friendly Low-cost Medium and High Density Fiberboard Production Method" disclosed by Chinese patent, CN201998256U "Fibreboard for Formaldehyde-free Furniture" disclosed by Chinese patent, CN102225571A "Using steamed fiberboard" disclosed by Chinese patent Explosive slurry dry method to produce glue-free fiberboard ", CN102172948A " surface impregnated wood fiberboard and its production method " disclosed by Chinese patent, all are by adding chemical substances of phenolic formaldehyde, urea formaldehyde and polyurethane or lignin adhesive To improve the physical properties of fiberboard, these methods are just simple bonding, no chemical reaction is involved in the process of hot pressing, it is difficult to take into account the physical strength and environmental performance of fiberboard, and the application limitations are very large