Performance comparison between the hottest screen

Performance comparison between silk printing ink and other printing inks

Abstract: in this paper, the performance of silk printing ink and other printing inks was tested experimentally. The results show that compared with other inks, silk printing inks have higher viscosity, ink layer thickness and high ink transfer rate

key words: printing ink/ink performance/ink layer thickness

hole printing, relief printing, gravure printing and lithography are called the four major printing techniques. Silk printing is a main printing method in hole printing. As well as silk printing, the printing methods that belong to porous printing include transcribed printing and typing, which go deep into the lithium battery industry. Yongxing Special Steel subsidiary plans to invest in the lithium battery new energy material project, including stencil printing, hollowed out printing and spray printing. Silk printing is an ancient printing method, also known as silk paint printing, silk leak printing, paste yarn printing. The three printing methods of flat, convex and concave are to transfer the ink to the surface of the substrate to realize the reproduction of pictures and texts; At this time, you can rotate the screw rod brush by hand on the right knurled part of the screw rod. The screw rod brush is a printing method that passes the ink through the hole of the plate and makes the ink miss the surface of the substrate. Therefore, there are more and more inks available for silk printing, and the substrate is not limited to paper. Metal, plastic, wood and so on can be used for silk printing. With the continuous expansion of printing ink and its application range, it is quite important to study the performance of printing ink. This paper analyzes the characteristics of printing ink through the method of printing experiments with printing ink and other inks and the comparison of ink performance

theoretical analysis

according to Newton's law of viscosity, the formula ①

τ=η D ①

where:

τ—— The shear stress applied to the ink

η—— A constant that does not depend on the shear rate is called the viscosity coefficient

d -- rheological rate gradient, d=dv/dr

when the fluid is subjected to an external force, it does not start flowing immediately. It must not start flowing until the applied external force reaches a certain degree. Such fluid is defined as plastic fluid, and its mathematical expression is formula ②:

τ=τ 0+ η D ②

τ 0 is the minimum shear stress value required by the external force to overcome the internal molecular structure of the fluid and make the fluid flow

the transfer process of printing ink is to reach the substrate surface through the hole under the action of external force, and the ink (fluid) needs to meet formula ③ through the hole

Q=πr4 Δ p/8 η L ③

where:

q - ink transfer amount

Δ P -- the pressure difference between the two sides of the wire, which is actually the scraping pressure

r - wire diameter

l - plate thickness

η—— Silk ink viscosity

from formula ③, it can be seen that the amount of ink transferred (missed printing) is inversely proportional to the viscosity of the ink and the thickness of the silk. The thickness of silk generally does not change much after plate making, which is taken as a constant value in this paper. Therefore, the key factor affecting the amount of ink transfer is the viscosity of ink

due to different colors of printing inks, the proportion of pigment and binder is different, so the viscosity naturally varies; The amount of inking is proportional to the pressure, so when the viscosity is high, the most studied is graphene and polyaniline composites, and the pressure should be correspondingly high; The pressure is directly related to the angle between the scraper and the plate

the experimental version adopts 350 mesh nylon and stainless steel wire made in Japan

printing inks used 45 yellow, 14 magenta, 58 green and 85 black inks produced by shenri Ink Co., Ltd., SS series yellow, magenta, green and black inks produced by Toyo Ink Manufacturing Co., Ltd. and ss8000 series printing inks produced by BASF. Other printing inks are domestic inks

the measuring instruments are Macbeth tr524 reflection densitometer, NXS-11 rotary viscometer and spm100 spectrophotometer

experimental printing materials mainly include paper, letterpress paper, offset paper and coated paper

the biggest feature of silk printing is that the printing ink layer is thick and the ink transfer rate is high 9 Check the air strike return to zero and energy loss. And its viscosity range is wide, which can determine the viscosity of the ink according to the substrate material, achieve a high ink transfer rate, and obtain sufficient ink layer thickness. By controlling the transfer amount of ink, the concentration range of color can be improved, and prints with rich texture can be copied. Silk printing ink has good drying adaptability, so silk printing can be applied to substrates with different texture materials, which can show a certain three-dimensional sense and significantly improve the image quality. However, due to the short head of silk printing ink and the limitation of silk itself, silk printing cannot print very fine printing products

conclusion

compared with other printing methods, silk printing has the following characteristics:

the viscosity range of silk printing ink is large, and the viscosity of ink can be determined according to the printing substrate material to achieve a high ink transfer rate and obtain sufficient ink layer thickness. The ink transfer volume is large, the covering power is strong, and the printed matter is bright in color and rich in texture

compared with other printing methods, silk printing has the characteristics of simple plate making and printing, and requires less equipment and operating costs; The layout is elastic and has low requirements for the surface of printing materials, and almost all surfaces can be printed with silk to obtain exquisite printing effect. Therefore, the printing materials that are difficult to be printed by other printing methods (relief, intaglio, lithography) and various industrial products can be surface printed by silk printing

source: keyin