Is printing ink toxic? This is what most printers are most concerned about. In the end, the printing ink is not poisonous. In fact, the answer to this question can not be generalized, because there are many kinds of printing. When the printing was not developed before, the printing ink used is generally toxic. , for example, we often say that flexographic printing, formerly called aniline printing, which is a toxic printing ink; but now the printing is all about non-toxic, moving toward green printing, take the flexographic printing, there are many Enterprises have adopted water-based inks, which can be said to be non-toxic.
Causes of ink toxicity
Printing inks are composed of pigments, binders and additives. For books, packaging, decoration, architectural decoration and other printing. As society's demand increases, the variety and output of inks also expand and grow accordingly.
The United States is the largest ink producing and consuming country in the world, followed by Japan, Germany third, and China fourth. With the rapid development of China’s national economy, the prosperity of the printing and packaging industry has led to the rapid growth of the ink manufacturing industry, which has made China’s rapid rise in the last decade or more to become one of the world’s largest ink manufacturers. Currently, the domestic ink industry scale is increasing by 10%. The above speed continues to grow rapidly.
A major problem with the toxicity of inks lies in the organic solvent, which accounts for 30% to 50% of the total amount of ink. For example, aromatic hydrocarbon solvents mainly refer to toluene, xylene, polycyclic aromatic hydrocarbons and their derivatives. They will evaporate into the air with the drying of the ink, polluting the air and threatening the health of the printing operator. There is also a volatile organic compound (VOC), which is a variety of types, such as alcohols, esters, ethers, ketones, mineral oils, and the like. Like aromatic solvents, it evaporates as the ink dries, polluting the air.
Another major problem with the toxicity of inks is pigments, standing 5% to 10% humorous, such as ink heavy metals, which should be the most contaminated, because children often have printed ink toys in their mouths, it is likely to absorb The possibility of some heavy metals. Therefore, the requirements for heavy metal content in the ink were first proposed. Heavy metals are mainly derived from pigments and auxiliaries in inks. Although most of the inks now have reduced heavy metal content, until now there are people using chrome yellow and chrome red to make inks.
Ink toxicity solutions
To solve the problem of ink toxicity, from a narrow sense, it is to use green ink.
To meet the environmental protection requirements of inks, we must first change the ink composition, that is, use environmentally friendly materials to formulate new inks. At present, environmental protection inks mainly include water-based inks, UV inks, water-based UV inks, and some alcohol-soluble inks.
(1) Water-based ink: The biggest difference between water-based ink and solvent-based ink is that the solvent used is water instead of organic solvent, which significantly reduces VOC emissions, can prevent air pollution, does not affect human health, is not easy to burn, and ink is stable. , Colorful, non-corrosive plate, simple operation, low price, good adhesion after printing, strong water resistance, rapid drying, it is particularly suitable for food, beverages, pharmaceuticals and other packaging printed matter, is the world recognized environmental protection printing materials, It is also the only ink approved by the US Food and Drug Association in all printing inks.
(2) UV curable inks: UV curable (UV) inks are inks that use ultraviolet light of different wavelengths and energies to form and dry inks under ultraviolet irradiation. Utilizing different UV spectra, different energy can be generated, and monomers in different ink binders can be polymerized into polymers, so the UV ink film has good mechanical and chemical properties. The main advantages of UV inks are: (1) no solvent; (2) fast drying and low energy consumption; (3) good gloss and vivid colors; (4) water resistance, solvent resistance, and good abrasion resistance. Photoinitiators in UV inks are compounds that are susceptible to photoexcitation. After absorption of light, they are excited into free radicals and the energy is transferred to photosensitive molecules or photocrosslinkers, causing UV inks to undergo photocuring reactions. At present, UV ink has become a more mature ink technology, and its pollutant emissions are almost zero. In addition to solvent-free, UV inks also have the advantages of not being easy to paste, clear dots, bright and bright ink, excellent chemical resistance, and low dosage.
(3) Water-based UV inks: Water-based UV inks are the new direction of UV ink research. Prepolymers in general UV inks are generally very viscous and need to be diluted with a reactive diluent. However, currently used thinner acrylate compounds have different degrees of skin irritation and toxicity. Therefore, while developing low-viscosity prepolymers and low-toxic reactive diluents, another development direction is to study water-based UV inks, that is, water. Ethanol and other diluents. At present, water-based UV ink has been successfully developed and applied in some printing.
In addition, alcohol-soluble inks, which mainly play a role in flexo printing, are also very small-pollution inks. They are mainly used in foods, medicines, beverages, tobacco, and daily-use packaging and printing that come in contact with the human body.
Causes of ink toxicity
Printing inks are composed of pigments, binders and additives. For books, packaging, decoration, architectural decoration and other printing. As society's demand increases, the variety and output of inks also expand and grow accordingly.
The United States is the largest ink producing and consuming country in the world, followed by Japan, Germany third, and China fourth. With the rapid development of China’s national economy, the prosperity of the printing and packaging industry has led to the rapid growth of the ink manufacturing industry, which has made China’s rapid rise in the last decade or more to become one of the world’s largest ink manufacturers. Currently, the domestic ink industry scale is increasing by 10%. The above speed continues to grow rapidly.
A major problem with the toxicity of inks lies in the organic solvent, which accounts for 30% to 50% of the total amount of ink. For example, aromatic hydrocarbon solvents mainly refer to toluene, xylene, polycyclic aromatic hydrocarbons and their derivatives. They will evaporate into the air with the drying of the ink, polluting the air and threatening the health of the printing operator. There is also a volatile organic compound (VOC), which is a variety of types, such as alcohols, esters, ethers, ketones, mineral oils, and the like. Like aromatic solvents, it evaporates as the ink dries, polluting the air.
Another major problem with the toxicity of inks is pigments, standing 5% to 10% humorous, such as ink heavy metals, which should be the most contaminated, because children often have printed ink toys in their mouths, it is likely to absorb The possibility of some heavy metals. Therefore, the requirements for heavy metal content in the ink were first proposed. Heavy metals are mainly derived from pigments and auxiliaries in inks. Although most of the inks now have reduced heavy metal content, until now there are people using chrome yellow and chrome red to make inks.
Ink toxicity solutions
To solve the problem of ink toxicity, from a narrow sense, it is to use green ink.
To meet the environmental protection requirements of inks, we must first change the ink composition, that is, use environmentally friendly materials to formulate new inks. At present, environmental protection inks mainly include water-based inks, UV inks, water-based UV inks, and some alcohol-soluble inks.
(1) Water-based ink: The biggest difference between water-based ink and solvent-based ink is that the solvent used is water instead of organic solvent, which significantly reduces VOC emissions, can prevent air pollution, does not affect human health, is not easy to burn, and ink is stable. , Colorful, non-corrosive plate, simple operation, low price, good adhesion after printing, strong water resistance, rapid drying, it is particularly suitable for food, beverages, pharmaceuticals and other packaging printed matter, is the world recognized environmental protection printing materials, It is also the only ink approved by the US Food and Drug Association in all printing inks.
(2) UV curable inks: UV curable (UV) inks are inks that use ultraviolet light of different wavelengths and energies to form and dry inks under ultraviolet irradiation. Utilizing different UV spectra, different energy can be generated, and monomers in different ink binders can be polymerized into polymers, so the UV ink film has good mechanical and chemical properties. The main advantages of UV inks are: (1) no solvent; (2) fast drying and low energy consumption; (3) good gloss and vivid colors; (4) water resistance, solvent resistance, and good abrasion resistance. Photoinitiators in UV inks are compounds that are susceptible to photoexcitation. After absorption of light, they are excited into free radicals and the energy is transferred to photosensitive molecules or photocrosslinkers, causing UV inks to undergo photocuring reactions. At present, UV ink has become a more mature ink technology, and its pollutant emissions are almost zero. In addition to solvent-free, UV inks also have the advantages of not being easy to paste, clear dots, bright and bright ink, excellent chemical resistance, and low dosage.
(3) Water-based UV inks: Water-based UV inks are the new direction of UV ink research. Prepolymers in general UV inks are generally very viscous and need to be diluted with a reactive diluent. However, currently used thinner acrylate compounds have different degrees of skin irritation and toxicity. Therefore, while developing low-viscosity prepolymers and low-toxic reactive diluents, another development direction is to study water-based UV inks, that is, water. Ethanol and other diluents. At present, water-based UV ink has been successfully developed and applied in some printing.
In addition, alcohol-soluble inks, which mainly play a role in flexo printing, are also very small-pollution inks. They are mainly used in foods, medicines, beverages, tobacco, and daily-use packaging and printing that come in contact with the human body.