Pigment for ink is the raw material that makes ink colorful, with the characteristics of insolubility in water and excellent alcohol resistance. Ink is a viscous mixture of various functional components mixed in a liquid, which can be printed, sprayed, scraped, and other ways to present the designed graphics, text, etc. on the substrate. Inks have a complex composition, and in addition to the basic colorants, linkers, and solvents, various functional additives improve the performance of the ink and enhance its printability on the substrate, as well as various other comprehensive properties.
KingChroma’s pigments for inks are available in a wide range of applications, including achromatic, color, body, luminescent, fluorescent, temperature-variable, and light-variable pigments, which can be tailored to meet customer needs, and we can also customize them according to customer requirements.
Mica Powder
Thermochromic Pigment
Photochromic Pigments
Pearl Powder
Glow in the dark powder
Chameleon Powder
UV Powder
Reflective Pigment
Colorants are divided into pigments and dyes. Pigment inks are dispersed in the form of granular suspension in ink. Dye inks are dispersed in the molecular form in ink. Pigment inks are usually attached on surfaces through binders. Dye inks can make objects colored inside. Colorants largely determines the hue, coloring power, covering power, fineness and density of ink.
Pigment inks are divided into inorganic pigments and organic pigments. Inorganic pigments are composed of simple elements, metal oxides, inorganic salts and their complexes. They feature long history, lower price and many varieties. They also have high covering power and excellent resistance. Organic pigments are mostly unsaturated organic matters. They are usually derivatives of heterocyclic benzene, naphthalene and other aromatic compounds. They have bright color, strong coloring power, high light and heat resistance, chemical stability, etc.
Dye inks have high solubility. They can be dissolved in water, oil or other organic solvents. Dyes can be divided into 11 types according to their properties and applications. In terms of the pH, dyes are divided into acid dyes, alkaline dyes and neutral dyes. By the dyeing method, dyes are divided into direct dyes, disperse dyes, reactive dyes, sulfide dyes, ice dyes, VAT dyes and cationic dyes. There are also dedicated non-toxic food dyes.
Common pigments for ink:
Color shifting inks are special inks. They have different colors in different environments. They are suitable for secure printing, watermarking, special signs, etc.
Methods/Steps
Note
It is critical to choose pigments. Different pigments have different response mechanisms. It is necessary to choose pigments according to needs.
Inkjet printing has certain requirements for the nanoparticle size. In practical applications, ink in printers is subject to fine treatment, to ensure that the pigment particle size meets the requirements. Special methods are suitable for preparation of nanoparticle pigments, such as the sol-gel method and vapor deposition method. These methods can control the particle size of pigments at a nanoscale level, to meet the requirements of inkjet printing.
The pigment particle size used to manufacture pigment ink is divided into nano-scale and micron-scale, where the average nano-scale particle size (LD50) is in the range of 40-125 nanometers, and the maximum particle size (LD90) shall not exceed 180 nanometers, and the micron-scale particle size is in the range of 0.125-0.300 microns.
The smaller the nanoparticle size, the clearer the printed image, and the better the color performance. Ink of smaller particle size flow faster in the inkjet head, thus accelerating spraying onto paper. Therefore, the moderate particle size of pigments can increase the printing speed while ensuring the image quality.
Electron beam curing ink (eb ink) can quickly change from liquid to solid in the irradiation of a high-energy electron beam. It is completely dried in a few milliseconds in the radiation of the electron beam. It has good printing gloss, film feeling and friction resistance. But the ink and corresponding radiation-drying device are expensive. Promotion of the ink is still difficult. But the ink is promising as it can save the drying time and ensure the product quality without causing environmental pollution.
The environmental friendliness of pigment inks involves the selection of raw materials. The conventional ink production often requires organic solvents. Among them, volatile organic compounds (VOCS) may cause air pollution. According to the environmental protection requirements, ink production enterprises should use water-based or curing inks to reduce the consumption of organic solvents. Water-based ink is a kind of ink with water as the medium. It is harmless, non-toxic and easy to clean, greatly reducing the pollution to the environment. Curing ink changes into a film through light curing or thermal curing, to avoid the release of organic solvents.
The binder is mainly to adjust the viscosity and fluidity of pigment based ink. Viscosity means how viscous the ink is. It directly affects the fluidity and print effect of ink. The binder can adjust the viscosity of ink to adapt to different printing materials and methods. For example, high-speed printers require low-viscosity ink to ensure the printing speed and quality. Low-speed printers require high-viscosity ink to ensure the printing quality and efficiency.
The binder can improve the adhesion of pigment based ink. Adhesion means how ink is adhered to printing materials. It directly affects the printing quality and durability. The binder can make pigments and solvents bound better, to form uniform ink particles, thereby improving the adhesion and durability of ink.
The binder can improve the stability and durability of pigment based ink. Stability means how stable the ink is during storage and use. It directly affects the quality and service life of ink. The binder can make ink particles more stable, to reduce separation and precipitation, thus extending the service life of ink. Durability means how durable the ink is during use. It directly affects the quality and service life of prints. The binder can make ink pigments distributed more evenly on printing materials, thereby improving the durability and quality of prints.
The light fastness of pigment ink refers to relative changes of ink color in light. In fact, colors of all inks will change more or less. If ink has good light fastness, printed products will have bright colors, dots in the layout will be full and solid. Prints will be full of three-dimensional sense and suitable for long-term storage. If ink has poor light fastness, prints are easy to fade and discolor.
Pigments affect the curing, fluidity, wettability and leveling of ink, in addition to the viscosity. Interaction between pigments and reactive base materials will lead to a decline in the shelf life of ink or change in ink color.
Different pigments vary in light absorption, reflection and scattering, so they affect curing to various degrees. Most pigments have a certain transmission area in partial light or visible light, namely, “spectral window”. Photoinitiators can fully absorb the light radiation energy within the “window”. Therefore, it is very important to determine the location of the “window” in order to choose a suitable photoinitiator.
That is, the photoinitiator should match pigments in the ink system. It should be within the wavelength range of weak light absorption by pigments. It is necessary to observe the relationship between pigments and the light absorption spectrum of the photoinitiator while using inks.
First of all, ink dispersants are mainly to reduce the viscosity of inks and improve their fluidity. In the printing process, inks should have certain fluidity to fill the print page. They should also remain stable to prevent precipitation and delamination in the printing process. Dispersants make inks easier to flow in printing machines by reducing the viscosity. They also keep inks stable to prevent precipitation and delamination.
Secondly, dispersants can enhance the coloring effects of inks. Since dispersants reduce the viscosity of inks, they are conducive to coloring of pigments and dyes in inks on the surfaces of prints. In addition, dispersants can enhance the dispersion of pigments and dyes, and make them distributed more evenly on the surfaces of prints, so as to achieve good coloring effects.
Ink dispersants can also improve the quality of prints. Because dispersants improve the dispersion and stability of inks, precipitation, delamination and caking do not occur in the printing process, and prints have high quality. Ink dispersants can improve coloring effects, so prints have more bright, full and truthful colors.
Roles of pigments in inks:
No. Because different ink manufacturers use different chemical materials, inks of different brands must not be mixed. Even inks of the same type may be different in chemical properties. Mixing often cause chemical reactions and ink deterioration, affecting the ink use and quality and even resulting in ink scrapping.
Pay attention to the impact of the following properties of pigments on the ink system:
(1) Dispersion. The dispersion of pigments depends on the particle size. The smaller the particle size, the better dispersion the pigment has, the higher stability the ink has, and the better gloss the print has.
(2) Coloring power. The coloring power of pigments depends on the crystal structure and optical properties. It refers to the ability of pigments to reproduce their colors in the mixing system.
(3) Covering power. Refer to the ability of pigments to cover the color of objects. It depends on the ratio of the refractive index of the pigment to that of the binder.
(4) Oil absorption. Refer to the proportion of oily substances (binder) in ink production with pigments.
(5) Density. The density of pigments has an important impact on the stability of inks. The lower the pigment density, the higher the ink stability.
The resistance, moisture content and pH value also have an important impact on the performance of inks.
Color shift pearl pigment is a very good-looking kind of pigment, the application field is also very wide, large to car paint, small to nail polish can be used, which can not be separated from its characteristics, pearlescent powder in screen ink printing in what proportion is more appropriate?
Pearlescent powder is suitable for a variety of printing paint ink, such as those for gravure, relief, flexographic, screen, or coated printing system, used to produce cardboard, wallpaper, business cards, tipping paper, greeting cards, etc. How to mix pearl pigment?
A lot of problems may occur when we use pearl pigment powder, such as unclear pearlescent effect, pinholes or small bubbles on printed surface, and large longitudinal stripes on the printed surface. What precautions should we notice when using such pigment?
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