Multi-Layer Anodized Lithographic Plate Precursor for Scratch Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithographic printing plate precursors face challenges in achieving optimal scratch resistance, on-press developability, press life, and reducing re-start toning (RST) issues, particularly in negative-working on-press developable plates, which limit their application to fewer than hundred thousand impressions due to chemical processing detriments and waste generation.
Innovation Solution
A lithographic printing plate precursor with a substrate having a grained and etched surface, featuring a multi-layer anodic oxide structure comprising an inner aluminum oxide layer with micropores less than 100 nm and an outer layer with micropores between 15 nm and 30 nm, along with a hydrophilic layer containing a copolymer with amide and phosphorus-connected groups, enhancing the substrate's properties for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional single-layer anodized substrates are used, then manufacturing is simpler, but scratch resistance and press life are insufficient
Solution Approach 1:
The substrate is divided into multiple anodized layers with distinct functions: a first anodized layer providing scratch resistance and a second anodized layer providing microporous structure for ink retention. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between strength and complexity.
Solution Approach 2:
The substrate uses a composite structure combining different anodized aluminum oxide layers with distinct properties. The first layer has higher scratch resistance while the second layer has controlled porosity, creating a composite material system that achieves both durability and functional performance.
2Ease of operation
If chemical developers are used for development, then on-press developability is achieved, but re-start toning issues and chemical waste increase
Solution Approach 1:
The patent converts the harmful chemical development process into a beneficial physical process. By designing the second anodized layer with controlled porosity (5-50 nm), the system enables physical entrapment of unreacted polymer particles through micropore filtration, eliminating the need for chemical developers and their associated re-start toning and waste problems.
Solution Approach 2:
The chemical development system is replaced with a physical development mechanism. The microporous structure of the second anodized layer provides mechanical filtration that physically retains unreacted particles, substituting the chemical developer system with a structural-based physical development approach.
3Ease of operation
If the outer anodized layer has larger micropores for better developability, then on-press development is improved, but scratch resistance decreases
Solution Approach 1:
The scratch resistance function is segmented from the porosity function into separate layers. The first anodized layer is optimized for scratch resistance with smaller pores, while the second anodized layer is optimized for developability with larger micropores (5-50 nm), allowing each function to be independently optimized without compromise.
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 effectively addresses re-start toning while maintaining long press life and on-press developability, ensuring the plates can be readily restarted after interruptions and maintaining high-quality performance across a larger number of impressions.
Implementation Method 1
anodized once or more times to provide an outermost hydrophilic aluminum oxide coating
Implementation Method 2
inner aluminum oxide layer...comprising a multiplicity of inner micropores
Data Source
AI summary
Lithographic printing plate precursors are prepared with a unique aluminum-containing substrate prepared using two separate anodizing processes to provide an inner aluminum oxide layer of average dry thickness (Ti) of 300-3,000 nm and a multiplicity of inner micropores of average inner micropore diameter (Di) of ≤100 nm. An outer aluminum oxide layer is also provided to have a multiplicity of outer micropores of average outer micropore diameter (Do) of 15-30 nm and a dry thickness (To) of 30-650 nm. A hydrophilic layer disposed on the outer aluminum oxide layer at 0.0002-0.1 g/m2 has at least a hydrophilic copolymer composed of (a) recurring units having an amide group and (b) recurring units comprising an —OM group directly connected to a phosphorus atom, wherein M represents a hydrogen, sodium, potassium, or aluminum atom.