1. Concept: solvent is a liquid that can dissolve other substances. In ink, solvent is the liquid that can dissolve resin or grease.
True solvent: solvent that can dissolve ink resin is called true solvent.
Cosolvent: the solvent that can not dissolve ink resin is called cosolvent, which can only dilute ink, adjust viscosity and adjust volatility.
True solvent and cosolvent are relative to resin. For example, xylene and ethanol can dissolve polyamide resin, but not nitrocellulose resin. So it is true solvent for polyamide resin and false solvent for nitrocellulose.
2. Effect of solvent
(1) Give the ink appropriate liquidity and viscosity, improve the transfer performance.
(2) Wet the surface of the printed matter to improve the adhesive absorption of the substrate.
(3) Adjust the drying rate of the printing process.
3. Solvents are classified by chemical structure
(1) Aromatics, such as toluene and xylene, have strong solubility, but have certain toxicity
(2) Esters have strong solubility and can dissolve nitrocellulose and artificial resin. Such as ethyl acetate, butyl acetate, etc.
(3) Ketones are mainly used to dissolve nitrocellulose
(4) Alcohols are miscible with water
(5) Ether glycol methyl ether, fiber dissolving agent and butyl fiber dissolving agent.
4. Characteristics of solvents
(1) Solubility: solubility is the ability of a solvent to disperse and dissolve solute. It is generally measured by solubility. Solvents have similar solubility parameters and cohesion. In most cases, when the difference of solubility parameters is less than 1, they can be mutually soluble. For the same reason, polymers are required to be dissolved in solvents with the same or similar solubility parameters.
(2) Volatility
The evaporation rate of solvent is related to the boiling point of solvent. Generally, the solvent with boiling point of 60-150 ℃ can be used for gravure printing.
a. Low boiling point solvent
The solvent with boiling point below 100 ℃ is a low boiling point solvent. Low boiling point solvent volatilizes quickly, the ink is easy to dry and has strong solubility, but it can not be used in large quantities. Otherwise, the ink color is easy to turn white and dull, and the leveling property of the ink becomes poor, and the uneven phenomenon will appear at the ink film thickness. Acetone, butanone and ethyl acetate belong to low boiling point solvents.
b. Medium boiling point solvent
The solvent with boiling point between 100-150 ℃ is a medium boiling point solvent. The ink prepared with medium boiling point solvent has high brightness and good luster, which can reduce the viscosity of the ink and improve the leveling property of the ink, but it will slow down the drying property of the ink.
c. High boiling point solvent
The solvent with boiling point above 150 ℃ is a high boiling point solvent. High boiling point solvent has strong solubility and can reduce the viscosity of the ink. The disadvantage is that the drying is very slow and the price is expensive. Such as hexanone, benzyl alcohol, dibutyl ester.
d. If the boiling point is above 250 ℃, it is a plasticizer. The use of solvents depends on the type of ink. Generally, mixed solvents are used to form a good gradient of solvent volatilization in the printing process, which is conducive to the good transfer of ink and the volatilization of solvent after printing.
Dongguan Beite packaging materials Co., Ltd. - located in Dongguan City, the world's manufacturing city, is a subsidiary of Beite packaging (China) Co., Ltd., with a plant area of 6000 square meters. It is a flexible packaging enterprise integrating R & D, production and sales. It has a complete set of domestic advanced production equipment, a scientific and humanized management system and a group of experienced technical personnel For backing, to provide customers with quality products and first-class service.
The company produces composite bags, roll film, fruit bags, aluminum foil bags, suction mouth bags, self-supporting bags, zipper bags, anti-static bags, special-shaped bags, etc., which are suitable for the internal and external packaging of food, daily chemicals, electronics, toys, medicine, cosmetics, industrial products and other industries.
We uphold the integrity of cooperation, good quality, thoughtful service business philosophy, the industry's recognition, products sold all over the world; welcome friends from all walks of life to inquire, visit our factory to investigate guidance and business negotiations