Coloring system for Rubber grommets
Traditional rubber grommets are mostly single black, and modern people require many rubber grommets to be brightly multi-colored. Therefore, the coloration of rubber is receiving increasing attention. Colorants are a class of materials that change the color of rubber. Rubber colorants are mostly pigments and small amounts of dyes.
First, the basic properties of color and the performance of colorants
1. The basic nature of color
Color is a visual nerve sensation caused by the stimulation of electromagnetic waves of a certain wavelength and intensity in the human eye. Electromagnetic waves having a wavelength between 400 and 780 nm are wavelength ranges that can be seen by the human eye, and are therefore also called visible light waves. When a visible light wave hits an object, the object appears black if it is completely absorbed; when the light wave is totally reflected (or transmitted), the object appears white; if the partially absorbed part is reflected (or transmitted), the object appears A certain color.
One color is determined by three basic parameters: hue (H), saturation (V), and brightness (C). The color is expressed by HV/C, for example, 5B2/4, 5B is a hue, 2 is lightness, and 4 is saturation.
Rubbergrommets colorant performance
The properties of the coloring agent include tinting strength, hiding power, light resistance, heat resistance, migration resistance, acid and alkali resistance, oil absorption, dispersibility, and toxicity, among which are important as follows.
(1) The coloring power refers to the ability of the coloring agent to give the colored object a color depth in its own color. The stronger the tinting strength, the smaller the amount of colorant used. The coloring power is related to the particle size of the coloring agent. The finer the particle size, the stronger the coloring power, and it is generally preferred to be around.
(2) Opacity refers to the ability of a colorant to block light from penetrating colored grommets, that is, the problem of the transparency of the colorant. Generally, the greater the hiding power, the worse the transparency. The opacity is related to the refractive index of the colorant and polymer and the size of the colorant particles. The greater the difference in refractive index between the colorant and the polymer, the better the hiding power.
(3) Light fastness, also known as fastness to light fastness, refers to the change of color when a coloring agent is exposed to certain conditions for a certain period of time. The color of the colorant after exposure is generally compared to a standard sample. Since the ultraviolet light in the sunlight has a relatively high energy, it can destroy the chemical bond of the colorant and cause it to fade. The light fastness is divided into eight grades, the eighth grade is the best, the third grade is flat, and the first grade is the worst.
(4) Migration resistance, also known as bleed, refers to the extent to which a colorant bleeds into a medium or migrates to a contacted substance.
It is highly mobile and easily causes blooming or color pollution. The bleed property is divided into 5 grades, 1 grade has no bleed, grade 2 has trace bleed, grade 3 micro bleed, grade 4 has slight bleed, and grade 5 has bleed. The bleed property includes water bleed, oil bleed, and paraffin bleed. Inorganic colorants generally do not migrate, and organic colorants mostly migrate. Generally, the inorganic salts (lake pigments) of organic acids have less migration. The molecular weights are lower than those of the latter, and the mobility is small. The migration of the pigment is greater than that of the double or condensed dich pigment.
(5) The oil absorption reflects the structural lowness of the colorant particles, and the carbon black DBP oil absorption value is a reason.
Toxicity requires no toxicity and low toxicity. In particular, rubber grommets products such as toys that are related to people’s lives and diets should be non-toxic. Generally, heavy metal colorants such as cadmium, lead, and selenium are toxic.