| 摘要 |
A hardenable phenol-aldehyde resin composition which is an aqueous dispersion containing 1 to 50% solids consists essentially of a heat-hardenable phenol-aldehyde resole resin having no more than 3.6% by weight of free aldehyde, and from 10 to 120 parts by weight of unreacted dicyandiamide for each 100 parts of the hardenable phenol-aldehyde resin, on a dry solids basis. The dicyandiamide is most suitably dissolved in water at an elevated temperature and the resulting solution is mixed with the phenol-aldehyde resin plus any other optional constituents. Suitable phenol-aldehyde resins are phenol-formaldehyde partial condensation products and phenol-amino compound-formaldehyde condensation products. The composition may be cured by heating during which the dicyandiamide is said to function as a cross-linking agent for the hardenable phenolic resin by reacting with methylol groups. Optional constituents which may be added to the composition are ammonium hydroxide, ammonium carbonate, gamma-aminopropyltriethoxysilane, a mineral oil emulsified with stearic acid, ammonium sulphate and a natural resin derived from pine wood. The compositions are suitable for binding glass and other vitreous fibres (see Division D1).ALSO:A mat of bonded, intermeshed glass fibres may be produced by introducing a heat-hardenable phenol-aldehyde resole resin binder composition into a fluid mass of the glass fibres which are being projected towards a collecting surface, depositing the projected fibres in association with the resin binder composition in a wool-like mass and heating the mass to harden and cure the resin binder composition. The heat hardenable phenol-aldehyde resole resin binder composition is an aqueous dispersion of 1 to 50% solids consisting essentially of a heat-hardenable phenol-aldehyde condensation product having no more than 3.6% by weight of free aldehyde and from 10 to 120 parts by weight of dicyandiamide per 100 parts of the hardenable phenol-aldehyde resin. The binder composition is suitably sprayed into a forming hood through which glass fibres are projected onto a foraminous conveyor and the wool-like mass so produced is cured at about 450 DEG F under pressure to produce a board like product. |
