The printing ink is composed of color materials, linking materials and auxiliary agents. After being mixed, the ink is rolled and formed into ink. The composition and inspection of the ink are mainly discussed below. First, the composition of the ink. Colored body (color material) Pigment organic pigment, inorganic pigment dye disperse dye, oil-soluble dye, other dye oil vegetable oil dry oil, semi-dry oil, non-drying oil mineral oil printing ink binder resin natural resin, natural resin derivative Synthetic Resin Solvents Hydrocarbons (Hydrocarbons), Alcohols, Ethylene Glycols, Esters, Ketones, Other Solvents Plasticizers Waxes Natural Waxes, Synthetic Wax Additives Dryers Other Dispersants, Wetting Agents, Crosslinkers, Anti-skin agents, stabilizers, matting agents, defoamers, anti-precipitation agents, photosensitizers, anti-agents, etc. (1) Colorants.
The inks for printing inks are formulated with pigments or dyes. Pigments are colored in the state of microparticles and evenly distributed in the binder; the dyes need to be formulated into a solution in the state of being used, and they are colored in a molecular state. At present, more pigments are used in oil black. Pigments are colored in the state of particles, so the size, shape, distribution, and surface properties of the particles have a direct effect on the ink properties.
Colorants for printing inks require a bright color and a strong coloring power. Since the ink film is only a few microns thick, it is required that the color materials have a sufficient color density. In addition, depending on the purpose of use, pigments are required to have different resistances. Commonly used pigments should have sufficient color density. In addition, depending on the purpose of use, pigments are required to have different resistances. (2) The link material.
The linking material, also known as media, is made from a small amount of natural resins, synthetic resins, cellulose derivatives, and rubber derivatives dissolved in a dry oil or solvent.
The role of the binder in the ink is to evenly disperse the pigment particles, so that the ink has a certain degree of fluidity, and the ink can form a uniform thin layer after printing, and after drying, an ink film with a certain strength is formed. The linking material should have a film-forming action so that the pigments can protect the pigments from the printing surface, and the pigments will not be powdered and peeled off from the substrate. The linking material should have a certain viscosity so that the ink can fully wet the printing. Things, drying in a short time. (3) Filler.
The fillers commonly used in inks include aluminum hydroxide [AL(OH)3], barium sulfate (BASO4), magnesium carbonate (MGCO3), calcium carbonate (CACO3), aluminum gallium white, and the like.
The filler is a white or colorless transparent powdered substance. Its role is to dilute over-saturated pigments with too much hiding power in accordance with the requirements of printing, reduce the amount of pigments, and reduce the cost of ink.
The filler can also adjust the fluidity of the ink, set off the color, and make the color of the ink more vivid. Therefore, the texture of the filler will directly affect the quality and output of the ink. Second, the nature of ink (a) color. The color of the ink, regardless of the degree of hue and tone levels, must be the same. The ink of the same number produced by the ink factory often varies in color due to the number of batches, and it is necessary to check if the ink is satisfactory when dispensing the ink.
(b) Coloring power. The coloring power is the concentration of the ink. The size of the ink's color, the degree of dispersion of the pigment in the ink, the amount of pigment, and the wavelength-selective reflection of the light.
Ink coloring power has a close relationship with printing quality and cost. Strong coloring ink printing less, printing adaptability, can print thin cable products.
(c) Covering power. The hiding power is the transparency of the ink. Ink transparency is one of the hallmarks of ink performance, which determines the color sequence of the product. In multi-color overprinting, the inks used have a high degree of transparency and show a third color. However, ink with poor transparency can only be used as the first color when printing, otherwise it will affect the quality of the product.
When the ink is coated with a very uniform film, the degree of display of the underlying color of the ink film is indicative of the transparency (or hiding power) of the ink.
(d) The fluidity of the ink (QB560-83). At a certain temperature, a certain volume of ink under a certain gravity squeezes, and after a certain time, the diameter of the ink spread out is called the fluidity of the ink. Fluidity can simply be thought of as a measure of the thinness of the ink, expressed in millimeters (MM).
(e) Dryness of the ink (QB562-83). The dryness of the ink is the time required for the ink to dry after being printed on the substrate.
Dryness is an important quality indicator for inks. Printing inks on substrates, whether it can be dried as required or not, is directly related to the printing effect. In general, many failures that occur during the printing process are caused by the poor dryness of the ink, such as: dirty (back dirty), is due to poor ink dryness. For this reason, the determination of ink dryness is an important means to get good ink quality and obtain good printing results.
(6) Viscosity of ink (QB564-83). The viscosity of the ink is an indicator of the quality of the ink. If the adhesiveness is too large, the pulling phenomenon will occur during the printing process. If the adhesiveness is too small, the dot enlargement phenomenon will occur. The viscosity of the ink will directly affect the quality of the printed matter.
(g) The viscosity of the ink (QB574-83). The viscosity of the ink refers to the degree of stickiness of the fluid. The viscosity of the ink is an important indicator for various types of ink. Each type of ink has a certain viscosity range, but for the same type of ink, the requirements are the same, that is, the faster the printing speed, the lower the viscosity of the ink.
The viscosity of the ink is related to a variety of factors: (1) It is related to the binder material. For the ink product formulated with the same kind of pigment, the viscosity of the binder material increases with the viscosity of the binder material. (2) In relation to the amount of pigments and fillers used, the greater the pigments and fillers used for the same binder, the greater the viscosity of the ink. (3) It is related to the size of the particles of pigments and fillers. For the same binder, the amount of pigment and filler is the same. The larger the particles of the pigments and fillers used, the smaller the viscosity of the ink and the smaller the particles. The greater the viscosity. (4) In relation to the dispersion of pigments and fillers, the better the pigments and fillers are dispersed in the binder, the lower the viscosity of the ink, and conversely, the greater the viscosity of the ink.
(h) The gloss of the ink (QB573-83). The gloss of the ink refers to the amount of light that can be felt from the regular reflection of the ink film surface. That is, the amount of light reflected by the ink print under a fixed light source is expressed in terms of reflectivity (percentage).
(9) Lightfastness of inks. The lightfastness of ink refers to the property that the color of the ink stays the same under the sun. In general, the ink must have good lightfastness. If the ink used is not lightfast, the prints will discolor and fade. The heat resistance of the ink is used to describe the degree of discoloration of the ink at a given temperature. The heat resistance depends mainly on the nature of the pigment. The radicals of certain pigments are not heat-resistant, and their structure changes at high temperatures, thus causing discoloration.
(x) Fineness. Fineness is the physical quantity that represents the size of the pigment in the ink, the size of the filler particles, and the uniformity of the distribution of the pigment particles in the binder.
The fineness of the ink is also one of the indicators that reflect the main properties of the ink. In the three-primary screen printing, the thicker the ink particles, the easier it is to paste, and at the same time, reduce the printing power of the printing plate. The finer the ink particles, the stronger the coloring power and the better the product quality.
(11) Density. When the temperature is at 20°C, the weight of one cubic centimeter of ink is the specific gravity of the ink. Its weight is expressed in grams. The density of ink has a special effect on printing. In the printing of high-density ink, the phenomenon of ink deposition on the printing plate is prone to occur. Especially in high-speed printing, the density of high-density ink is easily destroyed. Heap or paste failure.
When the ink is mixed, it is generally more important than the major ink consumption, while the ink with the smaller specific gravity has less ink consumption than the major ink under the same conditions. In addition, when the ink with the larger specific gravity and the ink with the smaller specific gravity are blended, Easy to layer, and change the color.
(12) Thixotropy. Refers to the thinning of the ink when it is subjected to an external force, and it also restores its original state after standing. Thixotropy is too strong, making it difficult to rotate in the ink fountain and making it difficult for the web transfer machine to transport ink. Third, the ink transfer No matter what kind of printing method used to print, ink must be put into the ink fountain, the printing process, the ink slowly out of the fountain, the ink roller rolling to extend to the layout, and finally transferred to the surface of the substrate.
Understand the factors that affect the transfer of ink, and master the ink supply in printing, in order to obtain high-quality printing products. The following sections describe several factors that affect ink transfer primarily:
(a) Printing pressure and ink transfer. As the printing pressure increases within a certain range, the ink transfer rate increases. But beyond this range, the printing pressure increases and the ink transfer rate no longer increases.
(b) Printing speed and ink transfer. As the printing speed is increased and the contact time between the paper and the printing plate is reduced, the amount of fixed ink that is pressed into the paper table is relatively reduced, and the ink transfer rate becomes smaller.
(3) Printing materials and ink transfer. Different substrates, the amount of ink is different, aluminum foil, plastic film transfer is the smallest, the highest level of printing paper (temperature 20 °C, printing pressure 23kg/cm2, printing speed 1 m / s, black version of the cable version).
The inks for printing inks are formulated with pigments or dyes. Pigments are colored in the state of microparticles and evenly distributed in the binder; the dyes need to be formulated into a solution in the state of being used, and they are colored in a molecular state. At present, more pigments are used in oil black. Pigments are colored in the state of particles, so the size, shape, distribution, and surface properties of the particles have a direct effect on the ink properties.
Colorants for printing inks require a bright color and a strong coloring power. Since the ink film is only a few microns thick, it is required that the color materials have a sufficient color density. In addition, depending on the purpose of use, pigments are required to have different resistances. Commonly used pigments should have sufficient color density. In addition, depending on the purpose of use, pigments are required to have different resistances. (2) The link material.
The linking material, also known as media, is made from a small amount of natural resins, synthetic resins, cellulose derivatives, and rubber derivatives dissolved in a dry oil or solvent.
The role of the binder in the ink is to evenly disperse the pigment particles, so that the ink has a certain degree of fluidity, and the ink can form a uniform thin layer after printing, and after drying, an ink film with a certain strength is formed. The linking material should have a film-forming action so that the pigments can protect the pigments from the printing surface, and the pigments will not be powdered and peeled off from the substrate. The linking material should have a certain viscosity so that the ink can fully wet the printing. Things, drying in a short time. (3) Filler.
The fillers commonly used in inks include aluminum hydroxide [AL(OH)3], barium sulfate (BASO4), magnesium carbonate (MGCO3), calcium carbonate (CACO3), aluminum gallium white, and the like.
The filler is a white or colorless transparent powdered substance. Its role is to dilute over-saturated pigments with too much hiding power in accordance with the requirements of printing, reduce the amount of pigments, and reduce the cost of ink.
The filler can also adjust the fluidity of the ink, set off the color, and make the color of the ink more vivid. Therefore, the texture of the filler will directly affect the quality and output of the ink. Second, the nature of ink (a) color. The color of the ink, regardless of the degree of hue and tone levels, must be the same. The ink of the same number produced by the ink factory often varies in color due to the number of batches, and it is necessary to check if the ink is satisfactory when dispensing the ink.
(b) Coloring power. The coloring power is the concentration of the ink. The size of the ink's color, the degree of dispersion of the pigment in the ink, the amount of pigment, and the wavelength-selective reflection of the light.
Ink coloring power has a close relationship with printing quality and cost. Strong coloring ink printing less, printing adaptability, can print thin cable products.
(c) Covering power. The hiding power is the transparency of the ink. Ink transparency is one of the hallmarks of ink performance, which determines the color sequence of the product. In multi-color overprinting, the inks used have a high degree of transparency and show a third color. However, ink with poor transparency can only be used as the first color when printing, otherwise it will affect the quality of the product.
When the ink is coated with a very uniform film, the degree of display of the underlying color of the ink film is indicative of the transparency (or hiding power) of the ink.
(d) The fluidity of the ink (QB560-83). At a certain temperature, a certain volume of ink under a certain gravity squeezes, and after a certain time, the diameter of the ink spread out is called the fluidity of the ink. Fluidity can simply be thought of as a measure of the thinness of the ink, expressed in millimeters (MM).
(e) Dryness of the ink (QB562-83). The dryness of the ink is the time required for the ink to dry after being printed on the substrate.
Dryness is an important quality indicator for inks. Printing inks on substrates, whether it can be dried as required or not, is directly related to the printing effect. In general, many failures that occur during the printing process are caused by the poor dryness of the ink, such as: dirty (back dirty), is due to poor ink dryness. For this reason, the determination of ink dryness is an important means to get good ink quality and obtain good printing results.
(6) Viscosity of ink (QB564-83). The viscosity of the ink is an indicator of the quality of the ink. If the adhesiveness is too large, the pulling phenomenon will occur during the printing process. If the adhesiveness is too small, the dot enlargement phenomenon will occur. The viscosity of the ink will directly affect the quality of the printed matter.
(g) The viscosity of the ink (QB574-83). The viscosity of the ink refers to the degree of stickiness of the fluid. The viscosity of the ink is an important indicator for various types of ink. Each type of ink has a certain viscosity range, but for the same type of ink, the requirements are the same, that is, the faster the printing speed, the lower the viscosity of the ink.
The viscosity of the ink is related to a variety of factors: (1) It is related to the binder material. For the ink product formulated with the same kind of pigment, the viscosity of the binder material increases with the viscosity of the binder material. (2) In relation to the amount of pigments and fillers used, the greater the pigments and fillers used for the same binder, the greater the viscosity of the ink. (3) It is related to the size of the particles of pigments and fillers. For the same binder, the amount of pigment and filler is the same. The larger the particles of the pigments and fillers used, the smaller the viscosity of the ink and the smaller the particles. The greater the viscosity. (4) In relation to the dispersion of pigments and fillers, the better the pigments and fillers are dispersed in the binder, the lower the viscosity of the ink, and conversely, the greater the viscosity of the ink.
(h) The gloss of the ink (QB573-83). The gloss of the ink refers to the amount of light that can be felt from the regular reflection of the ink film surface. That is, the amount of light reflected by the ink print under a fixed light source is expressed in terms of reflectivity (percentage).
(9) Lightfastness of inks. The lightfastness of ink refers to the property that the color of the ink stays the same under the sun. In general, the ink must have good lightfastness. If the ink used is not lightfast, the prints will discolor and fade. The heat resistance of the ink is used to describe the degree of discoloration of the ink at a given temperature. The heat resistance depends mainly on the nature of the pigment. The radicals of certain pigments are not heat-resistant, and their structure changes at high temperatures, thus causing discoloration.
(x) Fineness. Fineness is the physical quantity that represents the size of the pigment in the ink, the size of the filler particles, and the uniformity of the distribution of the pigment particles in the binder.
The fineness of the ink is also one of the indicators that reflect the main properties of the ink. In the three-primary screen printing, the thicker the ink particles, the easier it is to paste, and at the same time, reduce the printing power of the printing plate. The finer the ink particles, the stronger the coloring power and the better the product quality.
(11) Density. When the temperature is at 20°C, the weight of one cubic centimeter of ink is the specific gravity of the ink. Its weight is expressed in grams. The density of ink has a special effect on printing. In the printing of high-density ink, the phenomenon of ink deposition on the printing plate is prone to occur. Especially in high-speed printing, the density of high-density ink is easily destroyed. Heap or paste failure.
When the ink is mixed, it is generally more important than the major ink consumption, while the ink with the smaller specific gravity has less ink consumption than the major ink under the same conditions. In addition, when the ink with the larger specific gravity and the ink with the smaller specific gravity are blended, Easy to layer, and change the color.
(12) Thixotropy. Refers to the thinning of the ink when it is subjected to an external force, and it also restores its original state after standing. Thixotropy is too strong, making it difficult to rotate in the ink fountain and making it difficult for the web transfer machine to transport ink. Third, the ink transfer No matter what kind of printing method used to print, ink must be put into the ink fountain, the printing process, the ink slowly out of the fountain, the ink roller rolling to extend to the layout, and finally transferred to the surface of the substrate.
Understand the factors that affect the transfer of ink, and master the ink supply in printing, in order to obtain high-quality printing products. The following sections describe several factors that affect ink transfer primarily:
(a) Printing pressure and ink transfer. As the printing pressure increases within a certain range, the ink transfer rate increases. But beyond this range, the printing pressure increases and the ink transfer rate no longer increases.
(b) Printing speed and ink transfer. As the printing speed is increased and the contact time between the paper and the printing plate is reduced, the amount of fixed ink that is pressed into the paper table is relatively reduced, and the ink transfer rate becomes smaller.
(3) Printing materials and ink transfer. Different substrates, the amount of ink is different, aluminum foil, plastic film transfer is the smallest, the highest level of printing paper (temperature 20 °C, printing pressure 23kg/cm2, printing speed 1 m / s, black version of the cable version).