Environmental protection is the eternal theme of maintaining the human living environment. With the increase of people's awareness of environmental protection, green printing is an inevitable trend in the development of the packaging and printing industry. The development and application of environmentally friendly printing materials can effectively promote the development of environmentally friendly printing. This article has carried on the targeted specific analysis from the aspects of paper, ink, plate and printing method.

 

1 Eco-friendly paper

 

1) Vacuum spray aluminum paper

 

The raw and auxiliary materials used in the production of vacuum jet aluminum paper are odorless and non-toxic, and comply with the US FDA standards: its printing performance and mechanical processing performance are very good, and it can be applied to intaglio, letterpress, offset, flexographic, and screen printing, and can also be pressed Patterns, die-cutting, and even embossing: It is degradable, recyclable, easy to handle and recycle, and meets environmental protection requirements. It is an essential packaging material for export products.

 

2) Lightweight paper

 

Lightweight paper uses non-chlorine imported wood pulp as raw materials. It only needs to be beaten during production and does not need to be cooked, so there will be no waste gas and liquid discharge. Paper has high bulk and surface strength, which can achieve lower grammage to meet higher thickness requirements. If light paper is used for printing, it will be much lighter than ordinary offset paper, which not only reduces the transportation cost but also facilitates the convenience of readers to carry.

 

Many companies are now committed to the research of environmentally friendly paper. The Longmeng environmentally friendly paper developed by Hong Kong Longmeng Environmental Paper Group Co., Ltd. is made of 80% inorganic mineral powder and other non-toxic additives. The manufacturing process does not use wood pulp. And water resources make the paper industry completely environmentally friendly. Longmeng environmental protection paper has many advantages such as super water resistance and anti-mildew, mothproof and rapid degradation.

 

2Environmental protection ink

 

Ink is currently the largest pollution source in the printing industry, and the world's annual output of ink has reached 3 million tons. The annual global emissions of volatile organic compounds (VOC) caused by inks have reached hundreds of thousands of tons. These organic volatiles can form a more serious greenhouse effect than carbon dioxide, and will form oxides and photochemical smog under sunlight, which seriously pollutes the atmospheric environment and affects people's health. In addition, heavy metals and other harmful components in common inks for packaging and printing foods, toys, etc. will directly endanger the health of consumers. At present, the main environmentally friendly inks are as follows:

 

1) Water-based ink

 

The biggest difference between water-based inks and solvent-based inks is that the solvent used is water instead of organic solvents, which greatly reduces VOC emissions and does not affect human health. It is not easy to burn, the ink is stable, the color is bright, does not corrode the plate material, the operation is simple, the price is cheap, the post-printing adhesion is good, the water resistance is strong, and it dries quickly, so it is especially suitable for packaging and printing materials such as food, beverage, medicine, etc. The recognized environmentally friendly printing material is also the only ink approved by the American Food and Drug Association among all printing inks.

 

2) UV curing ink

 

Ultraviolet curing (UV) ink refers to an ink that uses ultraviolet light of different wavelengths and energy to form a film and cure the ink under ultraviolet irradiation. Utilizing the energy of the ultraviolet spectrum, the monomers in the ink binder are polymerized into polymers, so the color film of UV ink has good mechanical and chemical properties. At present, UV ink has become a relatively mature ink technology, and its pollutant emission is very small. In addition to solvent-free, UV ink has the advantages of not easy to paste, clear dots, bright and bright ink, excellent chemical resistance, and low dosage.

 

3) Soy ink

 

Soy ink is made of edible soybean oil (or other dry or semi-dry vegetable oils) mixed with pigments, resins, waxes, etc. This ink does not contain volatile organic compounds that pollute the atmosphere, is odorless and non-toxic, and is gradually replacing mineral oil inks centered on condensed web offset color inks. Affected by the upsurge of protecting the environment, it has been popularized and promoted very quickly, with Europe taking the lead, followed by Japan and South Korea, and 90% of newspapers in the United States have begun to use soy ink.

 

Some companies use linseed oil instead of soybean oil. Linseed oil is also a natural raw material, but it is a drying oil, which dries faster than soybean oil, and its printing performance is smooth and stable, and the effect is better than soybean oil.

 

4) Water-based UV ink

 

The water-based UV ink is made by adding a certain amount of water and 5% environmentally friendly solvent to the UV ink, combined with a special water-based resin. This enables the ink not only to retain the advantages of UV ink curing fast, energy saving, small footprint, environmental protection, etc., but also to meet the printing requirements of the ink layer being thinned by the volatilization of moisture after the ink is cured. This kind of ink is a new research direction in the field of UV inks.

 

5) Alcohol-soluble ink

 

Alcohol-soluble ink uses ethanol (alcohol) as the main solvent, non-toxic, safe, environmentally friendly, and hygienic. It is an ideal replacement product for traditional plastic inks. In South Korea and Singapore, alcohol-soluble inks have replaced toluene inks. The CL gravure alcohol-soluble composite plastic film ink was jointly developed by Hunan Jingxin Technology Co., Ltd. and Ye's (Hong Kong) Ink Co., Ltd. It is an environmentally friendly product made of alcohol-soluble nitrocellulose resin and other high-grade resins. Mainly used for chocolate food, cold snacks and ordinary fast food packaging. This ink not only promotes environmental protection, but also enhances the international competitiveness of my country's packaging industry. Alcohol-soluble ink, which is mainly used in flexo printing, is also a kind of ink with very low pollution, which is mainly used in packaging and printing of food, medicine, beverage, tobacco and alcohol, and daily necessities in contact with the human body.

 

3Environmental protection printing ink cleaning agent

 

CS-Y13 printing ink cleaning agent is refined from surfactants, emulsifiers, penetrants, rubber anti-aging agents and other additives. It has the characteristics of non-toxic, odorless, non-flammable, safe storage, low price, and strong washing and deinking ability. The ink cleaning agent meets the professional standards of Q/CS013-2002, and is currently the only product of its kind that has obtained China's green environmental protection label certification. This ink cleaning agent is non-flammable after emulsification, is harmless to the human body, and meets the requirements of safety, environmental protection and energy saving. It is a new generation of printing ink cleaning agent.

 

4Environmental protection plate

 

1) Green Star Edition

 

Compared with the traditional CTP process, the no-wash version introduced by Agfa, the Green Star version, reduces waste liquid by 93%, and compared with traditional film plate making, it reduces waste liquid by 96%. It has been used by more than 1,000 printers worldwide since it has been on the market for more than two years. This version does not require any chemical syrup, only the printing plate protective glue, and the waste liquid produced does not contain any toxic substances and can be directly discharged.

 

2) Free processing of CTP plates

 

Processing-free plate refers to that the plate can be printed on the machine without any subsequent processing after exposure and imaging on the direct plate-making equipment. In terms of plate-making methods, processing-free plates are divided into two categories: processing-free plates for DI (direct imaging on machine) printing presses and plates that are exposed and imaged on CTP direct plate making machines. Treatment-free CTP plates improve production efficiency, do not require chemical development, reduce energy consumption during exposure, reduce overall plate-making costs, and shorten plate-making process cycles. Today, when environmental protection is increasingly emphasized, its advantage is The environment is pollution-free and more obvious.

 

5Environmental printing method

 

Nowadays, most of the flexographic printing inks are water-based, alcohol-soluble, UV and other environmentally friendly inks, so there is no residual solvent content, and a trace amount of alcohol will not affect human health. The unique structure and printing principle of flexographic printing unquestionably meet the requirements of green packaging printing, so it is currently an ideal and recognized green printing method.