Friends, long time no see.Today we are going to talk about the development of photosensitive materials in the development of silkscreen printing materials.
The early photosensitive adhesive was based on gelatin (bone glue) and had no photosensitive effect.In case of light curing, colloids are crosslinked.However, after the crosslinking curing, this kind of colloid will slowly expand in the water, and still dissolve in the water for a long time. After long-term storage, it will dry out and become brittle, so it has been gradually replaced by PVA (polyvinyl alcohol) photosensitive adhesive.
The main body of PVA photosensitive adhesive is polyvinyl alcohol.Compared with gelatin, the quality of plate making is improved, the operation is simple, but the precision is still not high enough, the pollution problem has not been solved, has been gradually abandoned by the market.
In recent years, the development of photosensitive adhesive in China has progressed rapidly, and diazo salt photosensitive adhesive has been widely used.Diazo screen photosensitive adhesive is a new type of photosensitive adhesive, which has excellent resolution and anti-printing performance, and does not exist environmental pollution and toxic to human body.
(1) the mix ratio of diazo resin +PVA+ polymer emulsion PVA and polymer emulsion can be adjusted, with solvent resistance and water resistance.Because its absorption peak is around 375nm, it is more suitable to use metal halide lamp or ultra-high pressure mercury lamp.This kind of photosensitive liquid odor and skin irritation are less, and easy to modulate, easy to defilm regeneration, the price is lower.
(2) diazo resin +PVA+ polymer emulsion + acrylate monomer is an acrylate monomer which has added the insoluble photopolymerization initiator into the composition of diazo resin, PVA and polymer emulsion, and hardened at the same time through the cross-linking reaction of diazo resin and the polymerization reaction of acrylamide.High resolution and edge sharpness are also improved due to the improved water resistance and solvent resistance due to the increased polyacrylate crosslinking.
With the development of precision screen printing, such as screen printing in the solar energy, touch screen and other industries.High precision, low elasticity, good thickness uniformity, and has a strong mechanical load capacity of stainless wire mesh is more and more widely used, at the same time, its photosensitive adhesive has also put forward new requirements, the emergence of metal mesh photosensitive adhesive.This kind of photosensitive adhesive has many characteristics, such as good leveling performance, high resolution image force, strong bonding fastness with stainless steel screen and high number of printing resistance.
At the same time, in order to ensure that the printing coating is transferred from the screen aperture to the substrate surface smoothly, to improve the print resistance of the screen, the photosensitive adhesive containing fluoride has been developed successfully, and has been applied.
In order to save plate making time, the use of capillary non – forest is also more and more common.Although the price is slightly higher than coated photosensitive adhesive, but practicality and rapidity is still an important reason for its popularity and popularity.