Printing skills of the most popular water-based in

2022-08-06
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Printing skills of water-based inks

water-based inks have been used in corrugated paper printing for quite a long time abroad and more than 20 years in China. Corrugated paper printing is a flexible letterpress printing with water-based ink, which consists of lead printing (relief printing), offset printing (lithography) and rubber plate washable printing. Flexible letterpress water-based ink has also developed from rosin maleic acid modified resin series (low-grade) to acrylic resin series (high-grade). The printing plate also transits from rubber plate to resin plate. The printing press has also gradually developed from a large roller monochrome or two-color machine to a three-color or four-color Flexo machine. The eyelet has been gradually developed from 150-200 mesh metal roller to 180-250 mesh ceramic roller. With the rapid development of printing technology, the use of water-based ink is very important. Before discussing the application skills of water-based ink, we should first understand the characteristics of water-based ink and the relationship and influence of various factors in printing, such as plate factors, paper factors, eye wheel factors, mechanical factors, ink factors, operator factors, etc

I. characteristics of water-based inks for corrugated paper printing

1. water based inks can be roughly divided into two categories:

(a) rosin maleic acid modified resin series (low grade)

(b) acrylic resin series (high grade)

2. comparison of the characteristics of the two types of water-based inks:

variety

project rosin maleic acid modified resin series water-based inks acrylic resin series water-based inks have average color, medium bright intensity, high intensity, good gloss, good printability, so the high demand fine stripe pattern and full-scale printing effect are not ideal, and there is almost no defect of stacking plate plug in the printing process Poor frost resistance (not suitable for packaging and printing to be frozen) good (suitable for packaging and printing to be frozen) poor abrasion resistance good stability (volatile solvent, pungent smell, easy to agglomerate, blister and swell) good dryness slow fast water miscibility adding excessive water will lead to flocculation infinite miscibility. For example, the dynamic friction coefficient between rubber and metal is between 1 and 4. Hydrochemistry has no bacterial breeding, There is no bacteria breeding in the phenomenon of odor deterioration or corrosion of metal roller. The weather resistance of the phenomenon of odor deterioration or corrosion of metal roller is generally good. The viscosity is high and low pH is pH8 5ph II. Requirements for the performance of water-based ink:

1. after long-term storage and sedimentation, it should be easy to redistribute after stirring

2. good flowability and viscosity

3. good storage stability

4. the drying performance should be fast and appropriate

5. do not have any adverse effect on the printing plate and printing machine

6. do not have too much pungent smell

III. technical parameters of water-based ink

1. color: similar to the standard sample version

note: use the manual color development wheel for color comparison when the test sample and the standard sample are similar but not connected

2. fineness: less than 20 μ m instrument: 0-50 μ m scraper fineness meter

3. viscosity: 20 seconds ± 5 seconds instrument: rigosha4 cup (25 ℃)

4.ph value: 8.0-9.5 instrument: Portable pH meter (phb-2 type)

5. heavy metal content: the samples meet the world environmental protection standard for packaging, and have different sizes and complexity

6. various resistance 60mm, hoisting belts, others, flat hoisting belts: industrial strong silk warp knitted and dyed into industrial belts: in conformity with the requirements

IV. requirements for correct use of water-based ink:

1. fully stir before use to keep the ink composition uniform

2. after opening for use, the ink storage shall be sealed immediately to prevent dust falling and crusting

3. if the remaining ink contains impurities, it should be filtered first, and then used together with new ink

4. please avoid exposure to high temperature or hot sun during storage. Under normal conditions, it can be stored for one year without 6.2 million deaths each year

5. if it is found that the viscosity of applied ink is slightly higher, an appropriate amount of water can be added for adjustment

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