Three-Step Anodized Aluminum Substrate for Lithographic Plates
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Solution Overview
Problem
Current methods for producing lithographic printing plate precursors face challenges in achieving high scratch resistance, on-press developability, and press life while maintaining proper ink and fountain solution balance, often requiring trade-offs in chemical composition or structural features.
Innovation Solution
An aluminum-containing substrate is created using a three-step anodizing process to form unique aluminum oxide layers with specific pore diameters and densities, resulting in improved scratch resistance and ink/fountain solution balance without compromising on-press developability and press life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single anodizing process is used to form aluminum oxide layers, then the manufacturing process is simple, but the scratch resistance and ink/fountain solution balance are insufficient
Solution Approach 1:
The single anodizing process is divided into three sequential anodizing steps, each forming a distinct aluminum oxide layer with specific pore structures. The first anodizing forms a base layer, the second anodizing forms an intermediate layer with modified pore characteristics, and the third anodizing forms a top layer with optimized pore structure for ink retention. This segmentation allows each layer to contribute differently to scratch resistance and ink/fountain solution balance, achieving superior overall performance that cannot be obtained with a single anodizing process.
2Reliability
If the aluminum oxide layer porosity is increased to improve ink retention, then the ink/fountain solution balance improves, but the scratch resistance deteriorates
Solution Approach 1:
Different regions of the aluminum oxide coating have different porosity characteristics. The base layer has lower porosity providing structural integrity and scratch resistance, while the intermediate and top layers have progressively higher porosity to provide ink retention and ink/fountain solution balance. This local variation in porosity quality allows the coating to simultaneously achieve both scratch resistance and proper ink/fountain solution balance without compromise.
3Duration of action of stationary object
If the aluminum oxide layer thickness is increased to improve durability, then the press life extends, but the on-press developability worsens
Solution Approach 1:
The patent optimizes the thickness parameters of each individual aluminum oxide layer rather than simply increasing the total thickness. The base layer provides sufficient thickness for durability and press life, while the intermediate and top layers are optimized with controlled thicknesses that maintain on-press developability. By changing and optimizing the thickness parameters of each layer separately, the patent achieves both extended press life and good on-press developability.
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 substrate achieves enhanced scratch resistance and balanced ink/fountain solution performance, ensuring extended press life and efficient on-press development, as demonstrated by the specific structural features of the aluminum oxide layers.
Implementation Method 1
The aluminum-containing plate is anodized three times in sequence to form an inner aluminum oxide layer, a middle aluminum oxide layer, and an outer aluminum oxide layer
Implementation Method 2
anodized three times in sequence to form an inner aluminum oxide layer, a middle aluminum oxide layer, and an outer aluminum oxide layer
Data Source
Figure 1
AI summary
Lithographic printing plate precursors are prepared with a unique aluminum-containing substrate and one or more radiation-sensitive imageable layers. The aluminum-containing substrate is prepared by three separate and sequential anodizing processes to provide an inner aluminum oxide layer having an average dry thickness (Ti) of 500-1,500 nm and a multiplicity of inner pores having an average inner pore diameter (Di) larger than 0 and < 15 nm. A formed middle aluminum oxide layer has a dry thickness (Tm) of 60-300 nm and a multiplicity of middle pores of average middle pore diameter (Dm) of 15-60 nm, arranged over the inner aluminum oxide layer. A formed outer aluminum oxide layer comprises a multiplicity of outer pores having an average outer pore diameter (D0) of 5-35 nm and an average dry thickness (To) of 30-150 nm, arranged over the middle aluminum oxide layer. Dm is larger than Do that is larger than Di.