Research and Application of Vegetable Oil-based Printing Ink(2)

2 vegetable oil-based ink preparation process

The preparation process of vegetable oil based inks can be divided into two stages: the preparation of binders and the preparation of inks. The preparation of the binder is the core factor. The key to synthesizing high quality inks is to find suitable polymerization conditions and catalyst and raw material ratios.

2.1 Preparation process of the binder

The weight of the connecting material, known as the ink's heart, determines the quality of the ink.

2.2 Ink preparation process

3 "Green" properties of vegetable oil-based printing inks

“Green”, also known as “Environmental Friendly”, is a new concept in the form of “green chemistry” in the 1990s. Its goal is to develop environmentally sound chemical technologies that can eliminate or reduce the use and generation of harmful substances. Is a way to solve the pollution problem. The raw materials used in green chemistry should be non-toxic, harmless and renewable, and the products produced by Green Chemistry should also be non-toxic, harmless, and biodegradable.

The advantages of using vegetable oil-based inks are embodied in the following aspects:

(1) The oil resources are rich and renewable, meeting the requirements of green chemistry.

(2) The VOC content is low, and the vegetable oil itself is almost free of volatile organic compounds. The binders obtained by the polymerization of vegetable oils only generate a small amount of small-molecule and low-boiling compounds due to pyrolysis, and the cracking can be further reduced by controlling the reaction conditions. The International Printing Ink Manufacturers Organization (NPIM) statistics, due to the use of soybean oil-based inks, reduced the volatilization of VOCs by 15.75 million kg in 1992 and reduced the volatilization of VOCs by 10.35 million kg in 1997.

(3) Biodegradability, can be effectively degraded in soil. The data showed that under the action of Aspergillus and Penicillium at 25°C, 100% soya oil based binders degraded 60% after 5 days, degraded 68% after 12 days, and degraded 80% after 25 days. Under the same conditions, the mineral oil-based binder 25d only degraded 22 8% and the mineral ink only degraded 16%.
(4) Soybean oil-based binders are lighter in color and are good for the manufacture of high-quality color inks. Can improve the color of pure, vivid; enhance color reproduction; ink rheological performance is good, the ink balance ability is high, improved the ink transferability; reduced the dot gain; reduced through the failure, the dirty damage, Deinking failure. Especially for the regenerated weak fiber paper, the soybean oil-based ink is not easy to produce a nap phenomenon, and a clear image can be obtained, which is favorable for reducing the waste paper rate and saving costs.

4 Research status of vegetable oil-based inks

Vegetable oil based printing inks have historically been used for a long time. At the end of the 15th century, there was a vegetable oil-based ink. Soybean oil, cottonseed oil, linseed oil, safflower oil, tung oil, sunflower oil, etc. have a long history of application in the history of ink manufacturing. Due to the backward production process and technical level, there were many defects in the ink at that time. With the advent of high-speed printing, petroleum-based inks with quick drying properties have replaced vegetable oil-based inks.

By the 1970s, the oil crisis had prompted ink printers and printers to turn their attention to renewable oil substitutes. In the United States, some scientific research institutions have been developing mineral oil substitute products with the encouragement and support of national industrial policies. In the early 1980s, ANPA (American Newspaper Publishers Association, American Press Publishers Association) developed a substitute for mineral oil-based binders based on bitumen and tall oil fatty acids, which resulted in the synthesis of inks and patent applications. In 1991, the World Intellectual Property Organization Tuovinen, Juhani developed a news ink entirely modified with tall oil fatty acid as a binder. However, the difficulty in cleaning equipment caused by price factors, raw material supply, and bitumen limited the promotion and application of these products in the industry. Researchers began to turn their attention to cheap, widely sourced, biodegradable vegetable oils. In 1987, ANPA introduced a vegetable oil-based printing ink suitable for lithographic printing. Its main ingredients are alkali-smelted soybean oil, hydrocarbon resins and pigments. This product was originally difficult to promote due to price factors, and contains hydrocarbon resins, not completely out of dependence on oil. From the late 1980s to the early 1990s, researchers conducted a series of technological improvements. In 1991, Erhan and others synthesized alkali inks for lithography and letterpress printing using alkali-based soybean oil, Canola oil, cottonseed oil, sunflower oil, and safflower oil as raw materials, and they were synthesized in 1992 to meet printing requirements. The black and color ink, this 100% vegetable oil-based ink removes hydrocarbon resin, reduces the amount of pigment, provides a competitive price, enough to replace petroleum-based ink. In 1997, Sabin et al. synthesized rapeseed oil and sunflower oil modified alkyd resins to synthesize thermosetting and fast drying offset inks. This kind of ink replaces mineral oil with vegetable oil-derived fatty acid methyl ester, but the performance of thermosetting offset ink is not good. In recent years, the VOC content of traditional inks has drawn increasing attention, and the development of low VOC or VOC-free inks has become a hot topic. From 1994 to 1998, the United States successively introduced lithographic and gravure printing inks containing many vegetable oils as the main components. In these products, vegetable oils or modified resins or solvents are effective in reducing VOC content, but in order to ensure printing performance, they still contain a certain amount. Petroleum resin or solvent. In the United States, soyoil-based printing inks have been commonly used in newspaper and magazine printing.

In China, the ink manufacturing industry basically produces traditional synthetic resin inks, and vegetable oil-based inks have not yet been widely developed and applied. Today, environmental pollution is increasingly attracting people's attention, non-toxic inks will be the inevitable trend to replace traditional inks. However, there are few research work in this area in China. Only Niu Manzhi et al. did some preliminary experiments on the synthesis of vegetable oil-based ink binders.

5 Existing problems with vegetable oil based inks

5.1 Price issue

Vegetable oil based inks are somewhat more expensive than petroleum based inks. The price limits some manufacturers to use vegetable oil-based inks. For color inks, the price is mainly determined by the pigments, and the color vegetable oil-based inks are almost the same as the previous color inks.

5.2 Slow drying

With current technology, petroleum distillates in ink formulations cannot be completely replaced with vegetable oils due to limitations in the drying properties of vegetable oil based inks. Therefore, the primary purpose of research and development in this area is to ensure the maximum content of vegetable oils in printing inks that meet high quality and performance.

5.3 narrow application

Not all types of printing inks can be applied well to vegetable oil based inks. For example, gravure ink. Because this type of ink is a volatile drying type ink, the connecting material is required to be easily volatilized, and the vegetable oil-based ink has a low vapor pressure and a high boiling point and is a non-volatile solvent. Therefore, how to expand the application range of vegetable oil-based ink is also an urgent problem to be solved.