Flexographic resin plate making process

Photosensitive resin letterpress, photosensitive resin as the material, through exposure, development and photopolymerization letterpress, combined with phototypesetting, computer typesetting technology, not only improve the speed of plate making, and completely abandoned the lead alloy plate, so as to make the "cold typesetting" more perfect, create a new way for letterpress printing.

Photosensitive flexible version resin version, according to the shape of the resin before forming, can be divided into liquid fixed and solid grinding two.

(1) liquid fixed photosensitive flexographic printing resin plate

Liquid fixed photosensitive flexible resin version, called liquid flexible resin version. Before exposure, the resin is a viscous transparent liquid, and after exposure, it is crosslinked into a solid.

1. Composition of liquid flexible version resin

The main components of liquid flexographic resin are resin, crosslinking agent, photoinitiator, inhibitor and so on.

Wood veneer resin version is the main component of the photosensitive flexible resin version, usually aliphatic, aromatic saturated, unsaturated polycarboxylic acid and diol unsaturated resin condensation.

The role of crosslinking agent is to make liquid or solid resin polymerization under the action of ultraviolet light, cross linking and become solid or increase the hardness of solid. Commonly used crosslinking agents are acrylic acid, acrylyl carpal bone, ethyl dimethacrylate, glycol acrylate, etc.

Photoinitiators, also known as photosensitizers, are intermediates that transfer light energy in photopolymerization reactions. Benzoin and its ethers are often used.

Polymerase inhibitors are substances that inhibit the occurrence of dark reactions. P-phenylenediamine is usually used.

2. Liquid flexographic resin plate making process

The process of making liquid flexographic resin plate is generally carried out by spreading flow, exposure, washing, drying and after exposure.

(1) Superposition flow is made of photosensitive resin and injected into the hopper of the exposure molding machine. When the photosensitive resin flows out of the hopper, a scraper located at the top of the hopper squeezes the outgoing photosensitive resin to a certain thickness.

(2) Exposure is to cover the material flow with photosensitive resin, cover the transparent film, and then place the positive and negative film, first for positive exposure, then for the back exposure. The exposure time on the bottom side is usually 10 times that on the back side. High pressure mercury lamps with abundant ultraviolet rays are commonly used as light sources.

(3) Washing is done by placing the exposed sensitive flexible resin plate in a washing machine with dilute sodium hydroxide solution (concentration of about 3? 5%) rinse, generally at about 35℃ rinse. No photopolymerization occurs, the crosslinking resin dissolves, and the film is left with text and text parts photosensitive hardening.

(4) Drying and post-exposure is to wash the sensitive flexible resin plate and put it into the infrared dryer for drying. To flexographic resin plate drying and then exposure sensitive, the purpose is to increase the mechanical strength of the plate, improve printing tolerance.

Liquid flexographic resin version, belongs to the coating version, low price, poor dimensional stability, layout expansion with the change of temperature and humidity is greatly affected, suitable for the production of small line or text printing plate, mainly used for books.