The heat resistance of the pigment is mainly determined in consideration of its application in the iron printing industry. Because in the production process of the iron printing industry, the ink or paint needs to be baked after printing. At present, thermosetting inks also have this requirement.
It should be said that some pigments not only have the disadvantage of discoloration after high-temperature baking, but some varieties cannot even be used in the baking process.
(1) Equipment and materials
1. Utensils
(1) Similar to the determination of color items.
(2) Oven.
(3) Tinplate.
2. Materials
(1) Binder material: linseed oil long oil alkyd resin (solid content 70%, in petroleum solvent) 80%, ink oil 20%, cobalt naphthalate 0.5. Or other corresponding links.
(2) Method
Prepare the ink (color) paste with the toner Grinder in the following proportions.
Organic pigment: the ratio of pigment to binder is 0.6:2.4
Inorganic pigments: the ratio of pigments to binders is 1:1.
Then apply the oil (color) paste on the tinplate, and bake it according to the following conditions:
Bake for 60 minutes at 110°C;
Bake for 30 minutes at 150°C;
Bake for 20 minutes at 175°C.
According to the changes after baking, the rating is carried out.
(3) Precautions
1. The ink layer on the tinplate should be as thick as possible (it can be measured with a wet film thickness meter).
2. Before baking, the tinplate coated with ink paste should be cut into 4 parts, of which Lu part is used for baking and 1 part is reserved as standard.
3. The evaluation method of heat resistance level is also different, according to the situation in this article. It can also be rated as 4 levels, that is, excellent, good, fair, and poor.
4. The so-called baking for 60 minutes at 110°C refers to the measurement method of first raising the oven to 110°C, and then putting the printed iron sample into it.
