| 摘要 |
A resin binder comprises from 20 to 50 parts by weight of an alkaline-catalysed water-soluble and water-dilutable to about 2% solids content phenolic resin, 28 to 50 parts by weight of an alkali lignin and sufficient urea to make 100 parts, said urea being present in an amount equal to between 25 and 80% of the weight of the lignin. Specified alkali catalysts are sodium hydroxide, sodium carbonate, sodium sulphite, calcium hydroxide and barium hydroxide. The examples describe the admixture of an aqueous solution of urea and kraft pine lignin with phenolic resins made from phenol and: (1) paraformaldehyde and (2) formaldehyde. The resultant aqueous solutions are coated by spraying on mineral fibres and heat cured to bond the fibres.ALSO:Mineral fibre mats are made by attenuating molten mineral in a chamber to form fibres, spraying into said chamber an aqueous resin solution containing 20 to 50 parts by weight of an alkaline-catalysed water soluble and water-dilutable to about 2% solids content phenolic resin, 28 to 50 parts by weight of an alkali lignin and a quantity of urea equal to between 25 and 80% of the weight of the lignin to form a deposit on said mineral fibres, felting said fibres and heat curing the composition to bond the fibres together. |
