Titanium dioxide free multilayer coating system

A multilayer coating system comprising a layer of base coating which provides optical appearance on a substrate and a layer of clear top coating which provides surface protection and mechanical properties,

• wherein the multilayer coating system is free of extenders, TiO2, and other inorganic pigments,
• wherein the base coating is derived from an aqueous coating composition B comprising, in percentage by dry weight based on the total dry weight of the composition B,
• from 18% to 55% of an opaque copolymer a) comprising a multi-stage copolymer having at least one void per copolymer a) particle, and
• from 45% to 82% of a film forming single-stage (meth)acrylic emulsion copolymer b) compatible with the copolymer a), and comprising:
• (i) from 30 to 99.9 wt % of one or more C1-30 alkyl (meth)acrylate monomers having a Tg of less than 20° C.;
• (ii) from 0 to 60 wt % of one or more copolymerizable ethylenically unsaturated monomers other than the monomers having a Tg of less than 20° C.;
• and
• (iii) from 0.1 to 10 wt % of one or more monoethylenically unsaturated carboxylic acid or anhydride monomers, or salts thereof;
• and
• having a Tg of from −35° C. to 30° C.;
• wherein all proportions are based on the weight of all monomers used to make the (co)polymer;
• and
• wherein the clear top coating is derived from an aqueous coating composition T comprising, in percentage by dry weight based on the total dry weight of the composition T,
• from 20% to 85% of a multi-stage duller copolymer c) comprising, based on the total weight of copolymer (c), 60 to 95 wt % of a core of 95 to 99.1 wt % butyl acrylate and 0.1 to 5 wt % of allyl methacrylate and 5 to 40 wt % of a shell of copolymerized methyl methacrylate and ethyl acrylate;
• and having an average particle size of from 1 to 20 micrometers, and a Tg of from −60°-C. to 75°-C., and
• from 15% to 80% of a film forming single-stage (meth)acrylic emulsion copolymer d) compatible with the copolymer c), comprising:
• (i) from 30 to 99.9 wt % of one or more C1-30 alkyl (meth)acrylate monomers having a Tg of less than 20° C.;
• and
• (ii) from 0 to 60 wt % of one or more copolymerizable ethylenically unsaturated monomers other than the monomers having a Tg of less than 20° C.;
• (iii) from 0.1 to 10 wt % of one or more monoethylenically unsaturated carboxylic acid or anhydride monomers, or salts thereof;
• and
• having a Tg of from −35° C. to 30° C.;
• and
• wherein curing agents are absent from the top coating.