The main pollutants in screen printing

      In printing environmental pollutants, at present basically has the following 3 kinds: air pollutants, including aerosol (smoke, dust, fog), the harmful gas (sulfur oxides, hydrocarbon, carbon dioxide, hydrogen chloride, etc.).Water pollutants, including inorganic suspended solids (slag, iron), toxic pollutants (such as mercury, lead, chromium, phenol, chlorine liquid chemicals), acid and alkali pollutants (acid and alkali), oil (oils, lipids, etc.).In addition, hot water, high temperature exhaust gas and so on of heat will cause pollution to water and atmosphere.

      Solid contaminants: solid contaminants including paper, plastic, plastic packaging industry development situation), glass, metal, ceramic, wood chips and other solid waste.Noise and vibration also belong to environmental pollution.For silk screen printing, it mainly by the pollutants light-sensitive materials, printing ink (such as solvents and pigments).

1. The plate making photographic materials caused by the pollution

      Screen printing plate making of dichromate is commonly used in photographic materials, due to the plate making process to remove the waste liquid containing a large number of 6 chromium ion, toxicity, if human exposure to contain 6 chromium ion in the solution will generate diseases such as dermatitis, damage to the environment and waste liquid after discharge, seriously affect the normal growth of plants and animals.Therefore, the use of non-toxic diazonium salt and department of diazo resin emulsion type photosensitive glue to effect a radical cure of chromium ion pollution, will be the main direction of future process.

2. The pollution of printing ink solvent

      In printing, the printing ink of environmental impact is very big, ink printing industry is the largest pollution source.The ink annual output reached 3 million tons.Caused by the ink organic volatile global every year (VOC) emissions has amounted to hundreds of thousands of tons.These organic volatile, can form more severe than co2 greenhouse effect, and under the irradiation of sunlight can form oxides and light chemical smog, seriously pollutes the atmospheric environment, affect the quality of people's health and the environment.In addition, in food, toys and other packaging and printing, ordinary ink components such as heavy metals in the harmful components will direct a harm to human body healthy eaters.

(1) the effects on human health.

      Printing ink is made up of pigments, connecting agent, solvent, auxiliary agent.The organic solvent and heavy metals to human body harm is serious.Some of silk screen printing ink solvent volatilization or emissions into the air may pollute the environment, influence, the growth of plants, especially volatile ink to air pollution is very serious.In addition, some of the ink solvents and additives ignition point is lower, gathered in the air and reach a certain concentration, meet fire fire, etc.The ink pigment has two kinds, namely the inorganic pigments and organic pigments, the nature does not dissolve in water or other media, and has bright color and stability.Some inorganic pigments, contains lead, chromium, copper, mercury and other heavy metal elements, have a certain toxicity, can not be used in food packaging printing and children's toys, organic pigment in some containing biphenyl glue, which contains carcinogenic ingredients, is strictly prohibited.Organic solvents can dissolve many natural resin and synthetic resin, is an important part of all kinds of printing ink.Organic solvents can damage human body and the subcutaneous fat.Long-term exposure to certain solvent can make the skin weather-shack, coarse;If the infiltration of the skin or into the blood vessels, may be with endanger human blood and blood hematopoietic function;Solvent gas suction inlet pipe, bronchial, lung, or through the blood vessels, lymphatic spread to other organs, even may cause the body to chronic poisoning.

        Problem of toxicity of heavy metal ions in ink, pigment and dye all contain certain carcinogenic ingredients, there is a lot of harm to human body health.Composite packaging materials to use a lot of ink in print, organic solvent and adhesive, etc., although these materials have a direct contact with food, but in the process of food packaging and storage, some toxic substances will migrate to food, harm people's health.Printing ink, ethanol, isopropanol, butanol, propyl alcohol, butanone, ethyl acetate, butyl acetate, toluene, xylene and other organic solvents.Although these organic solvent by drying can remove most, but the residual solvent migrated to food the cause a harm to human body.In gravure printing ink solvent used in general have butanone, dimethyl benzene, toluene, butyl alcohol such as boiling point is smelly, toxic solvents.Especially the butanone, residual smell is very thick.Because of ink pigment particles is very small, adsorption ability is very strong, although at the time of printing has been heating dry, but due to time short, fast, often are not completely dry, especially on the ink area is larger, the printing ink layer thick, its residual solvent is more, these residual solvents were taken to a composite process, after the composite harder to run away, migrate slowly seep out.So must be solvent residue control to a minimum.

(1) plant ink

       Plants (such as soy ink, ink), it is to use soy or rapeseed oil, sunflower seeds, such as grease as connection material, its main characteristic is the pure natural soybean paste, using natural soybean oil as linking agent, and water and some additives as raw material preparation.

      After years of research and development of several kinds of vegetable oil formula test showed that soy ink, non-toxic pollution-free, rich and cooking yield of vegetable oils such as soybean oil, cheap, safe and reliable, the printing effect is good and conform to the standards of printing ink, especially superior environmental performance.Plants not only the advantages of the ink can reduce the release of volatile organic compounds and toxic, greatly reduces the average oil base ink is contained in a large amount of harmful volatile organic compounds, basically no VOC emissions when using, will not pollute the environment, and better plant frictional resistance of the ink, so can make newspapers print ink, readers are not affected by hand touch black, no bad odor stimulus again at the same time, so generally positive and welcome by readers.

       According to the American society of newspaper reports, newspaper readers usually cover than newspapers are more concerned with their hands to touch black (namely traditional oil printing ink rub resistance, and easy to be stained with black reader's hand).In addition, the boiling point of ink plant volatile component is much higher than oil to heat printing (such as laser printing, copying, etc.), not stick on the paper, as the volatilization which is plant significantly better than the ordinary ink printing ink characteristics of excellence.

       Also, the use of ink printing plant for recycling waste paper to take off the ink, it is more easy than ordinary ink deinking, less fiber damage and paper.At the same time to take off the printing ink after the waste ink residue than oil ink is easy to decompose (because soybean oil are biodegradable, and oil is indecomposable substance), and drainage treatment, and can control the discharge of water quality.Usually discarded waste ink, become the points of concern bothering printers and ink factory, cover hazards caused by the waste become industrial waste pollution caused by, so must be completed for processing.However soy ink can backfill in the new ink mixing, as waste reduction measures, is also conducive to environmental protection.Often use paper more than 80 newspapers in a recycled paper.Use soy ink printed in the use of print and regeneration process, will not produce environmental pollution of toxic and harmful substances, can be called green print.

       Some use soy ink print now Europe and the market, are marked for smart tags - "using environmental printing ink printing", to expand the social influence of environmental protection product.And, as a result of soy ink can show more strong and bright color effect, ink liquidity and excellent pigmentation, high transparency, colorful, color is deep, rich and beautiful, is not easy to rub off, etc., can greatly improve the quality of printing.And plant ink printing ink quantity is little, cost reduction, can increase unit printing quantity, to reduce the cost.Plant ink is one of the more conform to the requirements of the low carbon printing ink.Soy ink, broad scope, can be applied to flexible packaging, boxes, bags, sanitary products packaging, fast food lunch box, shopping bags, paper cups, cigarette case;All kinds of brand, newspapers, magazines, the non-drying label, beverage, wine, medicines and printing of various kinds of cosmetics.

      Osaka printing ink company recently introduced a new type environmental printing ink "Opis100", is a kind of win the American soybean association approved soy ink, it is soybean oil as the main body of the 100 oil ink, VOC content of less than 1, fully meet the environment association at the end of last year revised criteria for recognition of the green symbol of Japan's printing industry association of green environmental protection standards and the new change logo "lithographic printing ink V - 2" standard;In addition, the ink also has better stability and metastatic on board, the frictional resistance, gloss and hair color is good, the good education version fluid eligibility, easily biodegradable and deinking, and UV - OP varnish fusion, fine luster, for double color machine also has the characteristics such as excellent printing eligibility.Sheet-fed printing ink containing resin is more, and vegetable oil for at least 20. The ink for sheet-fed offset printing ink, in line with the Japanese environment association at the end of last year standard revision of the green flag, it has the following features:

       (1) in line with the new changes of the green mark "lithographic printing ink V - 2" standard;(2) is to win the American soybean association approved soybean oil ink;(3) in Japan's printing industry association of environmental standards;(4) meet GPN ordering guide;(5) is soybean oil as the main body of the 100 oil ink;6 VOC content of less than 1;All landowners in the stability of the machine and metastatic good;End frictional resistance, good gloss and color;A fine pet-name ruby education version fluid eligibility;Attending to biological decomposition and deinking;

(2), ink

       Scientists in the United States has long been committed to a bacteria called visual purple qualitative research of protein molecule.Natural material often can demonstrate such as semiconductor materials can easily gain a complex function.Bacteria rhodopsin is in a growing in salt marshes is called "salt products halophilic bacillus" body was found on the strength of the purple membrane.To illuminate its protein, can trigger a photochemical reaction times.Its principle is: the photochemical reaction ring along the transport protons around the cell membrane channel.The cell membrane of purple bacteria derived from is known as the "retina" rhodopsin composition.