Chipboard centre layer - contains additives of paper fibres derived from waste sludge from ink removal stage of used paper recycling

摘要

The sludge residue from the ink extraction stage in processing used paper, for recycling, is converted into a material for use in the centre layer of laminated chipboards. The water is initially extracted from the sludge, and the dried sludge is formed into solid particle and further dried to be mixed with glued or unglued wood chips to form the centre layer of the board. The material is spread over the lower board layer, with any mixed glue as required, to be covered by the upper layer and pressed into a laminated chipboard. The paper fibres are converted into an additive as pellets or flakes, with a residual moisture level matching that of the wood chips. The additives are sorted by a sieve with a mesh twice the size of the sieve used for the chipboard material sorting. The additives are unglued and the wood chips are glued, using a glue vol. corresp. to a centre board layer composed wholly of chips. The centre layer of the board is composed of 10-40 wt.% additives, and pref. 20-30 wt.% mixed into the material. The wood chips and the additives can be mixed together and glued at the same time. The paper fibres are developed from used paper, or from papermaking such as from papermaking waste water treatment, to give a sludge of paper fibres. The geometry of the wood chips matches the centre layer structure of conventional boards, with additives as flakes matching the wood chip geometry or pellets with a dia. of 2-5 mm. The wood chips have a residual moisture content of 3-12% and the additives are given a residual moisture content of 3-25%. The centre layer of wood chips and additives has the same thickness and strength of a centre layer composed wholly of wood chips. USE/ADVANTAGE - The sludge residue from ink removal during used paper processing is converted into a material for laminated chipboard prodn. The method takes the waste from used paper processing, together with usable fibres, as a material for high quality chipboards.