A waterborne coating composition and its applications thereof

A waterborne coating composition comprising:

• a) a water-soluble or water-dispersible binder;
• b) a cellulose nanofiber;
• c) a cosolvent of the formula (I)
• wherein
• the combination of X1 and n is (X1, n)=(H, 1) or (CH2—CH—CH2, 3), X2 and X3 are independently selected from the group consisting of hydrogen and alkyl having 1 to 8 carbon atoms, and m is an integer of 1 to 30;
• and
• d) an effect pigment;
• wherein
• the waterborne coating composition has a volatile organic content of less than or equal to 420 g/l without water, and
• a multilayer coating film comprising a basecoat layer obtained by application of the waterborne coating composition and a clearcoat layer on the basecoat layer has a brightness index of greater than or equal to 0.20, wherein the brightness) index=(L*15°−L*25°/L*15°, L*15° and L*25° respectively represent lightness values measured at viewing angles of 15° and 25° according to the L*a*b* color system (CIE lab).