| 摘要 |
Aqueous dispersions containing 15-35% by weight of a urea-formaldehyde polymer (UF polymer) which is characterised by - a formaldehyde:urea (F:U) ratio of (1.25-1.40):1, - a free formaldehyde content of less than 0.1% by weight, - a specific surface area of 5-30 m2/g, - a pore volume of 2-4 cm3/g, - a mean particle size of 0.05-1 [266F]m, and - a mean agglomerate size of 3-10 [266F]m, are particularly suitable as white pigments in papermaking. |
