Multilayer Polyurethane Underblanket for Offset Printing Press
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Solution Overview
Problem
Traditional underblankets for offset printing press blanket cylinders face challenges such as non-availability in desired thickness, mechanical stress resistance, peeling issues due to washing and dampening products, and costly production processes, leading to frequent replacements and compromised printing quality.
Innovation Solution
A multilayer underblanket structure comprising two polyurethane-based layers with different tensile moduli, one of which has an E-modulus of 2130 MPa +/- 20%, and optionally filled with organic or inorganic additives, ensuring high dimensional stability and compatibility to prevent peeling, and produced using techniques like extrusion, calendaring, or co-extrusion for optimal mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional underblankets are made with multiple layers of paper, fabrics, and adhesive polyester sheets to achieve desired thickness, then the thickness can be adjusted, but the assembly process becomes long and costly requiring manual superposition
Solution Approach 1:
The patent combines multiple separate layers (paper, fabric, adhesive polyester sheets) into a single integrated multilayer structure where layers are permanently bonded together. This merging eliminates the need for manual superposition and assembly of separate layers, reducing assembly time while maintaining precise thickness control through the integrated structure.
Solution Approach 2:
The invention uses composite materials consisting of multiple material types (paper, fabric, polyester) combined in a single structured underblanket. This composite approach allows the underblanket to achieve desired thickness and mechanical properties without requiring manual assembly of separate components, resolving the contradiction between precision and time loss.
2Manufacturing precision
If traditional underblankets use paper to achieve large thicknesses, then the desired thickness can be obtained, but resistance to washing and dampening products becomes poor requiring frequent replacements
Solution Approach 1:
The patent replaces paper-based composite structures with a multilayer composite consisting of fabric and adhesive polyester sheets. This new composite material combination provides both the desired thickness and superior resistance to washing and dampening products, eliminating the reliability issue while maintaining thickness control.
Solution Approach 2:
The invention changes the material parameters by substituting paper with polyester-based materials that have inherently better chemical resistance. This parameter change in material composition maintains the thickness capability while dramatically improving resistance to washing and dampening products.
3Reliability
If a polyurethane-based underblanket with elastic properties is used to respond to mechanical stresses, then printing quality improves, but the interface between layers becomes weak leading to peeling
Solution Approach 1:
The patent uses a multilayer composite structure where fabric and adhesive polyester sheets are bonded together. This composite design provides both the mechanical stress response capability and interface stability, as the bonded layers work together as an integrated unit rather than separate components that can peel apart.
Solution Approach 2:
The invention merges the fabric layer and adhesive polyester layer into a single integrated multilayer structure with strong bonding between layers. This merging eliminates the weak interface problem by creating a unified structure that responds to mechanical stresses as one unit, preventing peeling while maintaining reliability.
4Strength
If specific costly pre-treatments of polyester are applied to ensure adequate adhesion between layers, then interface strength improves, but production costs and complexity increase
Solution Approach 1:
The patent changes the material parameters by selecting adhesive polyester sheets that inherently provide strong adhesion without requiring pre-treatments. This parameter change in material selection maintains strong interlayer adhesion while simplifying the production process and reducing costs.
Solution Approach 2:
The invention uses readily available adhesive polyester sheets that provide adequate adhesion without requiring expensive pre-treatment processes. This approach accepts the use of standard, easily manufactured materials rather than investing in complex pre-treatment infrastructure, simplifying production while maintaining sufficient bond strength.
Data Source
AI summary
An underblanket of the blanket of a blanket cylinder of a printing press, particularly of the offset type, consists of a multilayer structure comprising a first layer comprising at least one polyurethane-based material, and at least a second layer comprising at least one polyurethane-based material, which is different from the one forming said first layer, and directly joined with said first layer by exploiting the intrinsic chemical/physical compatibility.