US Patent 7611668 Marker paint

A marker paint comprises 42 wt % to 52 wt % pigment, 31 wt % to 37 wt % acrylic resin and 17 wt % to 21 wt % silicone resin excluding solvent. The pigment comprises cobalt titanium oxide, titanium nickel antimony oxide, cobalt aluminum oxide or cadmium sulphide selenium to give a green, yellow, blue or red color respectively. The marker paint is used in conjunction with an irreversible temperature indicating paint to determine if there is any debris and/or dirt on the irreversible temperature indicating paint to affect the accuracy of the temperature measurement of the irreversible temperature indicating paint.