Paper sludge reuse
A team at the Technical University of Catalonia, Spain, says it has created a strong, fire resistant, waterproof and mouldable substance from paper ‘waste sludge’. The material could replace expanded polystyrene in packaging insulation applications.
‘There are many products made from waste paper, but [our process] does not need any pre-treatment to remove additives, ink [or glue],’ explains Dr Margarita Calafell.
The waste paper is treated with an ‘enzymatic cocktail’ of water, cellulases, hemi- cellulases, pectinases and laccase, which preserves the strength of the cellulose fibres. This is carried out at a temperature of 40ºC, after which the material is dried in an oven for two hours at 100ºC.
The final product is said to be a uniform, impermeable agglomerate material with density levels of 0.4g/cm3 and traction resistance of up to 1.6MPa.
‘There are no chemical additives, and the resulting material, as well as any secondary byproducts, is biodegradable,’ says Calafell. ‘With one kilogramme of paper waste it is possible to obtain almost one kilogramme of recycled material, which means that the losses are negligible.’
She adds that the sludge-based material can be moulded using traditional cellulose shaping techniques, and that it offers thermal insulation properties similar to rock wool. The incorporation of inorganic and sulphate salts (which are used in off-set printing and glossy publications) provides fire-resistance properties.
The group has patented the technique, and is investigating its use with other cellulose wastes, such as polymers, rubber, wood and cork.
Packaging Professional Magazine, 15 Sep 2009
‘There are many products made from waste paper, but [our process] does not need any pre-treatment to remove additives, ink [or glue],’ explains Dr Margarita Calafell.
The waste paper is treated with an ‘enzymatic cocktail’ of water, cellulases, hemi- cellulases, pectinases and laccase, which preserves the strength of the cellulose fibres. This is carried out at a temperature of 40ºC, after which the material is dried in an oven for two hours at 100ºC.
The final product is said to be a uniform, impermeable agglomerate material with density levels of 0.4g/cm3 and traction resistance of up to 1.6MPa.
‘There are no chemical additives, and the resulting material, as well as any secondary byproducts, is biodegradable,’ says Calafell. ‘With one kilogramme of paper waste it is possible to obtain almost one kilogramme of recycled material, which means that the losses are negligible.’
She adds that the sludge-based material can be moulded using traditional cellulose shaping techniques, and that it offers thermal insulation properties similar to rock wool. The incorporation of inorganic and sulphate salts (which are used in off-set printing and glossy publications) provides fire-resistance properties.
The group has patented the technique, and is investigating its use with other cellulose wastes, such as polymers, rubber, wood and cork.
Packaging Professional Magazine, 15 Sep 2009
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