Method of manufacture of medium and high density fibreboard with moisture and mildew resistance and low formaldehyde level

A fiberboard, manufactured by the steps of:

• (a) providing wood chips;
• (b) pre-steaming the wood chips by low-pressure steam having a steam temperature of 110-130° C.;
• (c) refining the wood chips into fibers by steaming under 165-175° C. and 0.8-09 MPa through a milling machine, then conveying to a spray pipe and adding urea-formaldehyde resin adhesive, nigrosine solution, refined paraffin and curing agent in the spray pipe;
• (d) conveying the fibers from the spray pipe to a blow line and feeding activated carbon to the blow line through a fan to mix with the fibers and then drying the fibers to control a water content of the fibers to between 8-10%;
• (e) separating fibers having the water content between 8-10% from heavy fiber bundles, glue blocks and other impurities and conveying to a measuring silo;
• (f) laying the fibers onto a mat formation platform uniformly to form a fiber mat by pre-pressing;
• (g) pre-heating the fiber mat to increase a temperature of the fibers and soften the fibers through spraying superheated steam;
• (h) processing continuous hot-pressing under high temperature and high pressure to form a raw board;
• (i) pre-trimming the raw board to a preset size;
• (j) cooling the raw board to a core temperature below 60° C. by flip cooling and maintaining for at least 48 hours;
• and
• (k) sanding and cutting the raw board to obtain final products.