| 摘要 |
Modified melamine-formaldehyde resins are made of a condensate of formalde-hyde, urea, melamine and modifying agents which contains: (a) a combination of 5 to 25 wt %, with respect to melamine, of dicyanodiamide and 8 to 30 wt %, wi th respect to melamine, of water-soluble polyalcohol with at least two hydroxyalkyl groups, and/or (b) 1.5 to 20 wt % amines having the formulas (Ia) and/or (Ib ), in which R1 and R3 are the same or different and depending on the meaning of X stand for a linear, branched or cyclic C1-C12 alkyl or alkylene radical and R2 stands for a linear, branched or cyclic C1-C12 alkylene radical; R4 and R5 can be the same or different and can stan d for H or for a linear or branched C1-CI2 alkyl radical; and X can stand for hydrogen, OH or NR4R5 and Y can stand for -O- or -NH-. The molar ratio of melamine to formaldehyde ranges from 1: 1.2 to 1: 5 and the molar ratio of melamine to urea ranges from 1: 0.1 to 1: 2.8. Also disclosed is the use of these resins to produce post-forming laminates.
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