| 主权项 |
1. A process comprising:
surface treating a cellulosic sheet-formed structures with a preparation comprising a micronized cellulose having a medium fiber length and medium particle size, respectively, below or equal to 15 μm, and at least one fluorescent whitening agent (FWA) having the formula (1)whereinR1 and R2 independently of each other mean H, SO3− or COOH, with the proviso that, if R1 is COOH, R2 is H, and vice versa;R3 and R5 independently of each other mean H, C1-C4-alkyl, C2-C3-hydroxyalkyl, CH2COO−, CH2CH2CN, CH2CH2CONH2 or CH2CH2SO3−;R4 and R6 independently of each other mean H, C1-C4-alkyl, C2-C3-hydroxyalkyl, CH2COO−, CH2CH2SO3−, CH(COO−)CH2COO−, CH(COO−)CH2CH2COO− or CH2-phenyl; orR3 and R4, or R5 and R6, independently of each other together with the nitrogen atom form a morpholine ring; and whereinM represents the corresponding charge equivalent selected from H+, an alkali metal cation, ammonium, C1-C4-tetraalkyl ammonium, ammonium which is mono-, di-, tri- or tetra-substituted by C2-C3-hydroxyalkyl radicals, and NH(R7)n(R8)m+, with R7 being C1-C4-alkyl and R8 being C2-C3-hydroxyalkyl, wherein both n and m are an integer of 1 or 2 and n≠m;
as well as mixtures thereof. |
