Types of thermochromic paints and pigments, why change color depending on temperature
Dyes change color over time only due to burnout, which occurs primarily due to direct sunlight. However, recently materials have appeared on the market that temporarily acquire a new shade under the influence of a certain temperature. Such properties are typical of thermochromic paint used to treat car bodies, clothing and other products.
Description and particularities
Thermochromic enamel is a paint that contains a special pigment that changes color when the temperature increases or decreases. This substance is in the form of rounded microcapsules with a diameter of 3 to 10 micrometers. Depending on the nature of the color change, thermochromic inks are divided into 2 types:
- Order. The color of the coating changes with an increase in temperature and recovers after a decrease.
- Irrevocable. The color of the material changes once upon exposure to temperature. The painted surface does not restore the original color.
Due to the fact that the shell of these microcapsules consists of liquid crystals, thermochromic enamel can be mixed with acrylic and other types of paints. This composition is used when processing iron, plastic and other surfaces.
This material has the following characteristics:
- heat resistance;
- there are no toxic elements in the composition (therefore, enamel is used for painting children's products);
- reduces the greenhouse effect, so that after processing the body, the car interior does not heat up in hot weather.
Another feature of thermochromic enamel is that when mixed with other materials, the percentage is selected depending on the area of application. So, to create a solution based on water or oil, it is necessary to take paint in the amount of 5-30% by volume. When processing plastics, this indicator decreases to 0.5-5%.
Varieties
The thermosensitive pigments that are part of this paint are divided into 3 types:
- Initially invisible. These pigments color the treated surface in a different color if the material is heated to 50-60 degrees.
- Visible at the start. These pigments become transparent when heated to 7-60 degrees. Once the exposure temperature is normalized, the substance returns to its previous hue.
- Multicolored. Such a pigment, when exposed to temperature, changes from one color to another.
The characteristics of thermochromic paint directly depend on the field of application.
Scope
As indicated, the scope of application of thermochromic paint directly depends on the effect to be achieved.If it is necessary to apply the composition to temperature-sensitive products, then it is recommended to choose a material whose pigments change color when heated to 230-280 degrees. For decorative processing, paints that are more sensitive to external influences are used.
car painting
Thermochromic enamel is often used for painting the car body.Thanks to this material, you can create a unique appearance. In addition, the application of the composition does not require specialized equipment.
It is recommended to use a spray gun to paint with thermal enamel. But you can use brushes to apply bitmaps.
When buying this material for the treatment of a car body, you must take into account that:
- the painted surface in direct sunlight loses its original properties;
- if scratches and chips appear, the entire bodywork must be repainted;
- a car whose body color changes is difficult to register;
- paint is expensive.
At the same time, using this material, you can make it so that when a certain air temperature is reached, the pattern applied to the body will appear. Images like these make the vehicle stand out from other vehicles.
For dishes that change color
Thermo enamel is used to color dishes, when heated, the applied pattern appears. This composition does not contain harmful components. Therefore, this material is used to color children's tableware. This is convenient because you can control the temperature of the food or drink being served.
Cloth
Thermochromic paints are also used to decorate clothing.Thanks to this treatment, it is possible to obtain T-shirts or trousers which, in contact with the human body, heat up and the applied pattern appears on the treated surface.
Souvenirs and decoration
Thermal enamels expand the possibilities for creating souvenirs and decorative objects. This material will allow you to create products with a "surprise" that appears when heated to a certain temperature. In addition, with the help of thermochromic paint, you can independently decorate objects, thereby receiving an original gift.
For prints
Thermal enamels have found application in prints. This material is used for catalogs containing perfume samples. In addition, thermochromic paint allows you to create original business cards, children's books, magazines, etc.
Thermal Hair Dye
Thermochromic hair dye helps to temporarily change hair color. This composition is based on silicone.
Depending on the type of pigments, the paint changes color at temperatures below +22 or +31 degrees. This product comes in the form of a spray bottle.
Thermochromic color palette
Thermochromic paint is:
- red;
- blue;
- YELLOW;
- Green;
- black;
- mauve;
- brown.
There are also less common shades:
- light blue, sky blue and dark;
- herbal yolk;
- cuff;
- Red rose;
- scarlet.
If necessary, these shades can be mixed, due to which one color first appears on the treated surface, and then another.
Compatible solvents
Before use, thermochromic enamels must be dissolved in (optional):
- the water;
- White spirit;
- ethanol;
- xylene;
- butanone oxime.
Heat sensitive enamels cannot be combined with propyl acetate, acetone and ammonium.
Selection tips
Before buying heat-sensitive paints, you need to decide on the scope of application of the material. This determines the temperature level under the influence of which the pigment changes color. That is, for clothes this figure will be 35-37 degrees, and for dishes - more than 50-70 degrees.
If the material is purchased for painting a car, it is recommended to purchase a special varnish together with the enamel, which will protect the surface of the body from direct sunlight. Also, before applying, you need to check how the color of the pigment changes. The shade indicated by the manufacturer on the package does not always appear after heating.