The hottest screen printing materials in the futur

Future silk printing materials

China's silk printing materials such as silk, photosensitive adhesive and ink have made great progress, but there is still a certain gap compared with the printing materials produced by foreign advanced manufacturers, such as high-strength, low elongation high mesh silk; High sensitivity non diazo photosensitive adhesive; UV ink, water-based ink, etc

I. silk

at present, China's annual import of silk has reached more than 1million m, and the imported products are mainly polyester and nylon yarn with more than 270 meshes. High density yarn with high technical content, high strength and low elongation yarn, antistatic yarn, calendering and other special treated yarn and polyester high mesh yarn all need to be imported

domestic polyester yarn and nylon yarn have a good market, and a small amount of polyester yarn is exported, but the types and specifications of domestic yarn are too few, and high-quality, high mesh and wide width yarn need to be developed

foreign countries have developed a new type of non-woven silk, which overcomes the trouble of coating photosensitive tape at the junction of warp and weft of traditional silk. Modern advanced ultra-fine graphic printing, fine level printing, high-precision positioning printing, special ink quantitative printing and large-scale color step printing all put forward higher requirements for the used silk: such as high strength, low elongation, repeatability, consistency, long service life, etc; Such as printing electronic micro components, integrated circuits, multilayer printed circuits, fluorescent digital displays, aerospace instrument flat panel displays and other high-tech products; For example, some printing requires anti-static, metallization, physical, chemical treatment or silk made of special materials

recently, the precision of printed circuit boards and electronic components is obvious, and the accuracy of size and position is very high. In addition to polyester, polyamide and stainless steel in the past, there are also yarns with high tensile polyester as the core and polyamide as the core sleeve. It is made of polypropylene fiber, with 330 mesh eyes and 23 longitude wire diameter μ m. Interlaced to 36 μ m. It is really epoch-making silk to obtain high tension. Moreover, in order to meet the requirements of precision, these wires have been treated by plasma, metal evaporation, polishing and other treatments

second, photosensitive adhesive

China's silk printing has made great progress in plate making photosensitive adhesive. Diazo photosensitive adhesive can meet the needs of polyurea to stand out from many waterproof materials. The long-standing manual engraving plate making method, 1 drawing plate making method and dichromate plate making method are basically replaced by diazo photosensitive (or diazo salt) plate making method with higher resolution. The water-resistant and solvent resistant diazo photosensitive adhesives produced in China are close to the foreign advanced level in the use effect, and can meet the requirements of template making with general accuracy

1. dichromate photosensitive adhesive

dichromate + ova (early protein). The storage period is shortened due to dark reaction, and the use of heavy metals has been restricted due to public hazards

2. Diazo photosensitive adhesive

① diazo resin + PVA + polymer emulsion. According to the mix proportion of PVA and polymer emulsion, it has solvent resistance and water resistance. Since the absorption peak is around 375nm, it is more suitable to use metal halogen lamp or ultra-high pressure mercury lamp. Because of less odor and skin irritation, this kind of photosensitive liquid is easy to modulate, and it is easy to remove film and regenerate, which is relatively cheap

② diazo resin + PVA + polymer emulsion + acrylate monomer. It is to add acrylate monomer dissolved in photopolymerization initiator into the composition of diazo resin, PVA and polymer emulsion, and harden at the same time according to the cross-linking reaction of diazo resin and the polymerization reaction of acryloyl group. Due to the increase of polymerization and crosslinking of acrylate, the water resistance and solvent resistance are improved, so that the high resolution and edge sharpness are also improved

3. non diazo photosensitive adhesive

① sbq.pva + polymer emulsion sbq.pva is the abbreviation of PVA added with styrene pyridine salt. SBQ, namely phenylethylpyridine salt, has high sensitivity and good water resistance. PVA is crosslinked and insoluble in water. This compound has high sensitivity and excellent storage stability in the state of coating photosensitive solution

② sbq.pva + polymer emulsion + acrylate because SBQ is used as crosslinking agent, high sensitivity is achieved, thick film version (300-400 μ m) It is also easy to make. In the current printing photosensitive agents, water-based and solvent-based inks can be used, and high sensitivity versions can be made, which means this kind of photosensitive agent

it is predicted that in the 21st century, SBQ photosensitive adhesive will replace diazo photosensitive adhesive and become the most used photosensitive adhesive. SBQ is a single liquid photosensitive adhesive, so photosensitizer is not needed; It can be used immediately, saving time and not wasting at all. The sensitivity is 3-5 times higher than that of diazo photoresist, and the exposure time of this part of consumer demand is about 1/5 of that of diazo. It can save energy, reduce costs and improve work efficiency. High resolution, excellent reproduction and development performance of the original. It can be used for fine line ultra precision printing. High concentration, good coating performance, smooth film surface, clear plate making lines, and can make thick film plates. It has excellent stability and can be stored for at least 3 years in high temperature and humid climate without any impact on plate making. Therefore, PS version (precoated version) or film can be made, which can be stored for a long time

in the past, the image accuracy of color overprint in silk printing can only reach 40-100l. As seen in CD (DVD) disc printing, audio-visual images and video game products have a sharp increase in demand for more colorful printing. For this reason, the image should reach more than 80-133l. The photosensitive adhesive belongs to non diazo photosensitive adhesive, which is the development direction in the future

III. Development Trend of printing ink

the categories of silk screen printing inks produced in China are relatively complete, including solvent based inks suitable for all kinds of substrate Weston 705, which have been approved by more than 20 major polymer manufacturers in the world, as well as newly developed water-based inks and UV inks. Some of them are of good quality and should be said to have developed rapidly. However, because the substrate of silk screen printing is very extensive, for example, most of the metal is used in the key components of mechanical equipment and cars, plastics, ceramics, glass, paper, leather, fabrics, etc., whether it is flat or special-shaped wire printing, it requires a large number of printing inks that match the substrate

at present, China's high-quality, high-precision printing inks and special-purpose inks, four-color additive inks and UV inks are almost imported. Therefore, the application and development of printing ink has infinite bright prospects. Therefore, printing ink factories should develop inks with corresponding fineness, fluidity, viscosity and other characteristics according to different substrates and the process requirements of printing materials and different industries, which is an important way to improve the quality of printing products and expand the printing field. In particular, our water-based ink UV ink has a promising future and needs to be vigorously developed

reprinted from: Jiagong electromechanical