Current situation and development of the hottest d

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Current situation and development of digital printing inks (2)

(3) surfactants

commonly used surfactants are benzene sulfonates, oxidized alkyl amines and amine salts, alkyne diols and fluorinated surfactants, which are generally 0.1% - 1.0% of the weight of the ink, preferably 0.5%

(4) dispersant

for pigment based inks, in order to ensure the dispersion stability in water, dispersants need to be added to the inks. Usually, water-soluble pigment dispersion resins are used, including styrene maleic acid copolymer, styrene maleic acid acrylic naphthalene maleic acid copolymer, styrene maleic acid semi ester copolymer, vinyl naphthalene acrylic acid copolymer, vinyl naphthalene maleic acid copolymer, vinyl naphthalene maleic acid copolymer, etc. Relative to the total weight of the ink, the concentration of the dispersion resin is preferably 0.05% - 2.0%

(5) pH regulator and other regulators

pH regulator is also called buffer, and inorganic acid or inorganic base can be used. Common inorganic acids include hydrochloric acid, phosphoric acid or sulfuric acid; Organic acids include methanesulfonic acid, acetic acid and lactic acid; Inorganic bases include alkali metal hydroxides and carbonates; Common organic bases include ammonia, triethanol and tetramethylethylenediamine

other additives can be added according to the specific use requirements of the ink, and local implementation plans can be developed, such as UV absorbers, metal chelating agents, defoaming silicone oil, etc. The content of these additives is generally 0.1% to 1.0% of the weight of the ink, preferably 0.5%

example of composition formula of liquid water-based ink:

dye 4.0% sodium benzenesulfonate 0.5%

chelating agent 0.5% sodium borate 0.5%

ethylene glycol 20.0% deionized water residue

2 Composition and performance of solvent based inks

(1) colorant

colorants in solvent based inks can use pigments or dyes, and their types and names are the same as those of water-based inks

(2) solvent

solvent based inks generally use organic solvents as the main solvent, and add an appropriate amount of water. Common organic solvents are diethylene glycol compounds and dipropylene glycol compounds, which are liquids at room temperature and pressure. Diethylene glycol compounds can be diethylene glycol ethers (especially alkyl ethers), such as diethylene glycol monomethyl ether; Or diethylene glycol esters, such as diethylene glycol monoethyl ether acetate; It can also contain polyethylene glycol monoether compounds and other polar organic solvents, such as alcohols (methanol, ethanol, propanol, etc.), ketones (acetone, methyl ethyl ketone, cyclohexanone, etc.) and carboxylic esters

the mixing ratio (weight ratio) of diethylene glycol compound and dipropylene glycol compound is between 20:80 and 80:20, and the content is preferably 85% - 95% relative to the total weight of the ink

(3) dispersant

when pigments are used as colorants, polyester polymer compounds should be added to the ink mixture as dispersants. The preferred amount is 30% - 120% of the weight of Colorants (especially pigments)

(4) other additives

other additives include stabilizers (such as antioxidants or UV absorbers), surfactants, adhesive resins and wetting agents. Antioxidants can be BHA (2,3-butyl-4-oxyanisole) or BHT (2,6-di-tert-butyl-p-cresol); UV absorbers can be benzophenone compounds or Benzotriazole Compounds; Surfactant can use any anionic, cationic, amphoteric or non-ionic surfactant; Adhesive resins include acrylic resin, styrene acrylic resin, rosin modified resin, polyester resin, polyamide resin, plastic materials with high heat resistance and high cooling capacity, oxygen resin, polyethylene vinyl acetate, ester copolymer with weak foundation, cellulose resin, etc. In addition, the use of wetting agents can help prevent the ink from drying or scaling in the nozzle. Commonly used wetting agents include polyols, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, tetraethylene glycol, polyethylene glycol, glycerol, etc., and their dosage is 5.0% - 6.0% of the total weight of the ink mixture

the composition formula of liquid solvent ink is as follows:

formula 1:

pigment 4.0%

polyester polymer (dispersant) 2.4%

polycyclic ethylene derivative 0.5%

mixed organic solvent 93.1%

formula 2:

oily dye 1.0% oil 30.0%

propanol 29.0% formamide 40.0%

3 Thermal imaging ink

thermal transfer imaging technology is widely used in digital printing, in which thermal sublimation technology is the main technology. Thermal imaging ink can be either water-based ink or solvent based glass fiber reinforced plastic pipe/elastic element fatigue life testing machine technical parameters: the main difference between ink and the previous two inks lies in the difference of colorants. This paper introduces the composition of a thermal sublimation ink, which mainly includes thermal sublimation dyes and pigments, solvents (transfer agents, water-based or alcohol based lotion), surfactants, water-based adhesives, lubricants, dispersants, defoamers. According to the weight percentage, thermal sublimation dye and pigment disperse blue (or magenta, yellow, cyan, black) account for 10% - 35%, water-based preservative 1.0% - 6.0%, surfactant 1.5% - 6.0%, water-based adhesive 1.0% - 7.0%, lubricant 1.0% - 4.5%, dispersant 0.5% - 4.0%, defoamer 1.0% - 6.5%, and the rest are water or a mixture of water and alcohol. The specific formula is as follows:

disperse blue ac-e10% chloroform 2.5%

ethylenediamine tetraacetic acid 3.0% sodium carboxymethyl cellulose 3.3%

polyol 2.0% potassium pyrophosphate 1.0%

emulsified silicone oil 2.2% distilled water residue

the component proportion of the formula can also be changed according to the characteristics of specific printing materials

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