Study on Properties of Water-resistant Screen Printing Photopolymers (1)

The water-resistant photosensitive polymer material is a very important functional polymer material for the production of printed circuit boards and thick film integrated circuits. Especially for printed circuit boards with special applications, when water-based inks are used, the screen printing adhesives are required to have a relatively high water resistance, so as to prevent the screen printing plates from being damaged by the aqueous ink during printing, thereby improving the precision of the printed circuit. Degree and image stability. In this paper, photosensitive polymers with diazo resin as photosensitizer and polyvinyl alcohol (PVA) and polyvinyl acetate (PVAC) as film formers were added. The addition of PVAC has a great influence on the photographic system. For this reason, the photosensitivity and water resistance of the photosensitive polymer have been studied.

1 Experimental section

1.1 Preparation of Photoreceptor Solution PVA (Beijing Chemical Industry Products) and PVAC (Beijing Chemical Industry Products) were mixed in different proportions as required, and diazo resin photosensitizer (Beijing Xinya Printing Factory) was added for use. Print photographic prints.

1.2 Exposure In the dark room, the above photosensitive liquid was coated on the nylon net into a uniform film of a certain thickness, dried in an oven at 40° C., and irradiated under a high-pressure mercury lamp for a certain period of time.

1.3 Development

The exposed stencil plate was developed in water at 50° C., dissolved material was dissolved, and dried for use.

1.4 Sensitivity measurement

In this paper, the residual film yield method was used to determine the sensitization characteristics. The residual film yield was plotted on the ordinate and the exposure time was plotted on the abscissa. On the characteristic curve, the exposure time multiplied by the exposure time at 50% of curing is found to be the sensitivity.

S=Ixt
Where: S - sensitivity (mJ/cm2); I - illumination (mW/cm2); t - exposure time (s).

1.5 Water resistance test

After the exposed screen printing screen was soaked in water for 48 hours, the peeling test was performed with a self-adhesive tape to observe the film-off phenomenon.

2 Results and Discussion

2.1 Effect of Ultraviolet Light on Photosensitive Materials The photocrosslinking mechanism of diazo resin and PVA is as follows:

(to be continued)