Analysis of Improved Example of Water-based Flexographic Ink Technology

3 performance testing:

The basic properties of the ink were tested according to the corresponding gravure ink detection standards, and the results of Table 1 were obtained.

4 Formulation Environmental Performance Analysis: First of all, we analyze the components of the basic formula. The basic ingredients contained in the formula are pigment, resin solution, ethanol, ethylene glycol butyl ether, defoamer and water.

In terms of pigments, the development of organic pigments has been extremely rapid in recent years. This is because inorganic pigments have a series of advantages over inorganic pigments. Organic pigments have more vivid colors, brighter shades, and higher levels than inorganic pigments. The coloring power can produce varieties with high color strength and high transparency to meet the requirements of high-grade coatings and printing inks. Most organic pigments are very toxic and do not contain heavy metals in inorganic pigments. The high-grade organic pigments not only have excellent fastness to light, weather fastness, heat resistance and solvent resistance, but also are superior to inorganic pigments in acid and alkali resistance. The pigments used in our experiments were all imported high-grade organic pigments, and the performance was very good. Therefore, the toxicity of pigments was not much discussed.

The main components of the aminated resin solution in the base formulation are resin, ethanol, ammonia, and deionized water. Among them, the impact on the environment is nothing more than ethanol and ammonia, but in fact the amount of ethyl ether contained in ethanol is extremely small, so it has been excluded from the VOC black list (see the German blue sky environmental standards, HBC12-2002 "Technical Requirements for Environmental Labeling Product Certification - Waterborne Materials"). The resulting oil film has a relatively strong irritating odor. After analysis, it should be caused by ammonia. Ammonia, although it has good solubility properties, is not compliant with environmental standards (GBZ 2-2002) due to severe irritating odors. The use of ammonia water is not conducive to the stability of the pH value of the ink during long-term storage. Therefore, we must look for an odorless solvent that can replace ammonia, without compromising the printability of the ink. In the study, we found that the two solvents, monoethanolamine and 2-amino-2-methyl-1-propanol, have better performance than ammonia (see Table 2). If these two solvents are used instead of ammonia, it should be considered from the viewpoint of performance. It is more ideal, but considering the principle of cost consideration, we have adopted an eclectic solution that mixes the three solvents in different proportions. It can be seen from the test results that the obtained ink is not only extremely odor-free. , And the pH is more stable.

Ethylene glycol butyl ether, according to the previous analysis shows that the cosolvent has a serious harm to the human body and must look for an environmentally friendly product that can replace it. Taking into account that propylene glycol ethers have the common characteristics of alcohol ether solvents - strong dissolving power and slow evaporation, so as a solvent can improve the leveling of the coating, gloss and fullness, reduce the minimum film forming temperature of the emulsion, overcome some of the coating Membrane morbidity is a good solvent for acrylics.

From the proportion of the basic formulation, we found that the proportion of organic volatiles was {(20×1%+23)%×355 (VOC content in aminated resin solution)+15×1%+15 ( The VOC content in the base ink formulation)}×100%=234%>17%, indicating that the VOC content in the basic formula is excessive and needs improvement. Our goal is not only to reduce the toxicity of solvents in the ink, but also to reduce the proportion of organic solvents. In order not to destroy the printability of the ink, through analysis, we adopted the method of adding the resin emulsion and reducing the content of ammonia water to achieve the purpose of reducing the volatile organic content. The improved experimental formula is as follows:

2) Improved recipe

1 Abrasive base formula (take black ink as an example):
Pigments 110%
Acrylic resin solution 295%
Ethanol 90%
Resin emulsion 300%
Propylene glycol ether 80%
Wetting Dispersant 05%
Waterborne wax 10%
Antifoaming agent 05%
Leveling agent 05%
Water 100%

2 aminated resin liquid formulations:
J678 resin 30%
Ethanol 200%
2-amino-2-
Methyl-1-propanol 80 %
Monoethanolamine 45%
Ammonia (boiling point:-) 45%
Deionized water 200%

3 performance testing:
The basic performance of the ink was tested according to the corresponding test standards, and the results shown in Table 3 were obtained:

4 Experimental conclusions and analysis: This experiment is based on the basic formula, in the aspect of environmental protection, replaces ethylene glycol butyl ether with less toxic propylene glycol ether, at the same time, we are non-toxic and non-irritating when preparing the aminated resin solution. The odor of 2-amino-2-methyl-1-propanol and monoethanolamine replace part of the ammonia, reducing both the toxicity and the pungent odor. Only taking into account the cost, we did not replace all of the ammonia. As a result, the VOC content of organic volatiles dropped to 1052%, which is lower than the U.S. VOC standard.

3 Conclusion

With the emergence of the energy crisis and the unfolding of the world's environmental protection movement, the voice of ink and wash has become higher and higher, and our country is far behind the times in this respect. China has joined the World Trade Organization. If solvent-based inks are used to print exported packaging products, it will be difficult for these products to enter the international market. The result must be at a disadvantage in competition. Therefore, the development of ink painting will play a significant role in the development of the national economy and society, and its prospects will surely be broad. (Text / Wang Dong)