How to choose the resin and it’s effect on to the properties of Thermochromic Ink？
1 :The viscosity and solid content of the resin has the very important influence of the Color concentration and surface gloss of the Thermochromic Ink .
This effect is pretty obvious of black .Because of the pigment content of Thermochromic Ink is much higher than the ordinary ink.So if using the ordinary ink resin to making Thermochromic Ink will lead it can not be used because of the high viscosity .Therefore, when making the ink can only reduce the dosage of resin ,thus increase the amount of solvent, then reduce the ink viscosity. But When the ink layer of the printer fully dry.Because of the low content ,can not bridge the space between the pigments.And the surface of the Ink layer will be uneven , the burnish got lost and the light get the formation of diffuse.So when the apparent of the ink layer concentration is low ,the gray level will be high. For black ink, it will appear grey but not black(if printing a layer of the transparent light oil on the surface , will clearly feel the black degree get increased)Therefor, when mixing the Thermochromic Ink must use the resin which have the high content and low viscosity(low molecular weight polymer), as so to obtain the good results.
2: The relationship between the resin type and the color concentration of the Thermochromic ink and transparency after decolorization :
Heat achromatic series (Series R) Thermochromic pigments used to be in printing the patterns like "Covering - Showing". It required the Thermochromic ink layer surface on the printer completely covered the lower designI when the color comes out. Should achieve the decolorization temperature and close to the transparent. Make the lower pattern be clear displayed. In those types of using,if the choice of the resin is Incorrect,after the ink layer decolorization,will produce a lot of white mist. And the lower pattern will be fuzzy.The basic reason is that Optical refractive index of the selected resin and the Thermochromicr pigments are not the same. Countless microcapsules scattered in the ink layer cause a lot of optical reflection interface.Just like when broke a piece of transparent glass ,after crushing,will get the formation of white opaque phenomenon.Choosing the right resin,can reduce the refraction phenomenon of Thermochromic ink layer in a big degree.And make the ink layer after decolorization be more transparent.In general, using the alkyd resin and acrylic resin will have a much better transparency, and if that’s the polyamide resin and nitrocellulose the transparencywill be worse.