Photosensitive resin composition, printing plate precursor, and flexographic printing plate

Abstract

Disclosed is a photosensitive resin composition that provides an excellent water developability, drying property, and image reproducibility. The photosensitive resin composition comprises a water-dispersible latex (A), a rubber (B), a surfactant (C), a photopolymerizable monomer (D), and a photopolymerization initiator (E). A ratio of a mass of the component (C) to a total mass of the components (A), (B), and (C) is within a range of 0.1 to 20%. A ratio of a mass of the component (A) to a total mass of the components (A) and (B) is within 20 to 90%. A size of a dispersed phase consisting mainly of the component (B) is 10 µm or smaller.

Description

technical field [0001] The present invention relates to a photosensitive resin composition, a printing plate precursor, and a flexographic printing plate. Background technique [0002] In the past, letterpress printing, gravure printing or offset printing was performed on objects to be printed, such as packaging materials, labels and magazines, etc., using printing plates. Among them, letterpress printing is performed using letterpress. In this letterpress, flexographic printing plates can be used for a variety of objects to be printed, including objects to be printed that are made of soft materials. [0003] The original plate of the flexographic printing plate includes a photosensitive layer made of a photosensitive resin composition on a substrate of PET resin or the like. The flexographic printing plate irradiates the photosensitive layer with ultraviolet rays through the negative film in contact with the photosensitive layer, and the unhardened portion is removed to f...

AI Technical Summary

Problems solved by technology

[0008] However, the photosensitive resin composition of Patent Document 1 has a problem that the developing process takes a long time because there are many components with low water solubility and / or water permeability.

The long development time is not only a problem of workability, but also the surface of the original printing plate is rubbed by the brush for a long time in order to remove the unhardened part during development, so the image reproducibility is low due to the loss of fine dots, etc.

[0009] In addition, Patent Document 2 contains a surfactant in the photosensitive resin composition in order to shorten the developing time, although this is effective for shortening the developing time, however, since the main component of the photosensitive resin composition is water-soluble or water-swellable polymer matter, so the drying time after water development is too long, so the practicality is low

[0010] Furthermore, if the surfactant of the composition disclosed in Patent Document 2 is simply added to the water-dispersible latex, the photopolymerizable monomer, the rubber, and the photopolymerization initiator of the composition disclosed in Patent Document 1, fine grains on the negative film can be reproduced. Image reproducibility of screen dots may decrease

[0011] Therefore, conventional photosensitive resin compositions do not satisfy water developability, dryness, and image reproducibility at the same time.

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