Backcoat Layer Scratch Resistance for Lithographic Plates
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Solution Overview
Problem
Infrared-sensitive lithographic printing plates lack sufficient scratch resistance, particularly when transported without a slip sheet, leading to mechanical damage and defects during handling and processing in CTP systems with automatic feeders.
Innovation Solution
A photosensitive lithographic printing plate with a backcoat layer comprising a cured urethane acrylate oligomer having a Vickers hardness of 0.2 or less, which reduces mechanical stress and prevents scratching during transport and handling without the need for a slip sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithographic printing plates are packaged without a slip sheet to eliminate cost and disposal issues, then cost is reduced and environmental friendliness is improved, but the photosensitive layer is easily damaged due to rubbing during transport and handling
Solution Approach 1:
The patent introduces a backcoat layer as an intermediary between the support and the external environment during transport. This backcoat layer, comprising a cured urethane acrylate oligomer with specific molecular weight and functionality, acts as a protective mediator that prevents direct contact and rubbing between stacked plates, thereby protecting the photosensitive layer without requiring a slip sheet.
Solution Approach 2:
The patent changes the physical and chemical parameters of the backcoat layer by specifying precise molecular weight ranges (500-2000), functionality ranges (2-6), and Vickers hardness limits (0.2 or less). These parameter changes create a backcoat with optimal protective properties - soft enough to prevent scratching while maintaining structural integrity during handling and transport.
2Strength
If a backcoat layer with high hardness is used to provide structural support, then mechanical strength is improved, but the photosensitive layer is easily scratched during handling and transport
Solution Approach 1:
The patent precisely controls the molecular weight (500-2000) and functionality (2-6) parameters of the urethane acrylate oligomer to achieve a Vickers hardness of 0.2 or less. This parameter optimization creates a backcoat that is mechanically strong enough for structural support yet soft enough to prevent scratching of the photosensitive layer during handling.
Solution Approach 2:
The patent creates a composite structure where the backcoat layer (cured urethane acrylate oligomer) is combined with the support and photosensitive layer. This composite material system achieves both mechanical strength from the oligomer structure and scratch resistance through the controlled softness and flexibility of the cured backcoat.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides excellent scratch resistance and prevents image defects during transport and processing, even when stacked without a slip sheet, enhancing the reliability of the printing process in automated systems.
Implementation Method 1
an infrared-absorbing agent that absorbs light and generates heat
Implementation Method 2
in exposed areas (non-image areas) heat generated therein weakens the interaction between the infrared-absorbing agent and the alkali-soluble resin
Data Source
AI summary
An infrared-sensitive lithographic printing plate is provided that includes a support, a recording layer on one side of the support, the recording layer being capable of forming an image by irradiation with infrared rays, and a backcoat layer on the side of the support opposite to the side having the recording layer, the backcoat layer having a Vickers hardness of 0.2 or less.