Rosin-Based Inert Polymer for Low-Shrinkage Radiation-Curing Coatings
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Solution Overview
Problem
Existing radiation curing coatings, particularly those used on low energy plastic substrates like PET, PVC, PE, and PP, suffer from significant shrinkage during curing, leading to poor adhesion and mechanical properties, and current inert resins like CAB and DAP are expensive, sensitive to hydrolyzation, and emit bad odors.
Innovation Solution
A polymer synthesized through a multi-step reaction involving polyhydroxy-, polyepoxy-, and polythiol-functionalized compounds with α,β-unsaturated carboxylic acids and rosin acid, without terminal vinyl, acrylic, or methacrylic groups, to reduce shrinkage and enhance adhesion on non-absorbent surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inert resins like CAB or DAP are used in radiation curing coatings, then adhesion on low energy plastic substrates is improved, but cost increases and odor problems occur due to butyric acid release
Solution Approach 1:
The patent replaces expensive conventional inert resins (CAB, DAP) with a newly synthesized polymer that achieves the same adhesion function without the harmful odor byproducts. The new polymer is designed to be a cost-effective alternative that eliminates the need to tolerate bad odors during curing.
Solution Approach 2:
The patent addresses the hydrolyzation sensitivity of conventional resins by designing a new polymer with enhanced stability. Instead of working around the hydrolyzation issue, the invention creates a resin that is inherently more resistant to hydrolysis while maintaining the desired adhesion properties on low energy substrates.
2Strength
If crosslinking density is increased to improve mechanical properties, then strength increases, but shrinkage increases leading to poor adhesion
Solution Approach 1:
The patent modifies the chemical structure of the inert resin by introducing specific functional groups and controlling molecular weight and architecture. These parameter changes allow the resin to provide mechanical strength enhancement without the excessive shrinkage that plagues conventional systems with high crosslinking density.
Solution Approach 2:
The patent creates a composite coating system where the newly synthesized polymer works synergistically with the curative components. The inert resin matrix provides a balanced system that delivers mechanical properties while controlling shrinkage through its specific molecular structure and interaction with other coating components.
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 polymer effectively reduces shrinkage and improves adhesion on low energy plastic substrates while being derived from natural materials, offering improved mechanical properties and avoiding environmental odor issues.
Implementation Method 1
The shrinkage occurs during the curing of a coating composition, since the dimensions of the coating composition before and after the curing alter as a consequence of the crosslinking reaction
Implementation Method 2
The crosslinking reaction, which is typically a radical polymerization of ethylenic groups
Implementation Method 3
A polymer being suitable as inert component of a radiation curing coating and in particular of a radiation curing ink... to obtain a proper adhesion
Data Source
Figure 1
AI summary
A polymer is obtainable by a method comprising the following steps: a) reacting a-i) at least one compound being selected from the group consisting of polyhydroxy-functionalized compounds, polyepoxy-functionalized compounds, polythiol-functionalized compounds, compounds comprising at least one group being selected from hydroxy groups, epoxy groups and thiol groups and at least a different group being selected from hydroxy groups, epoxy groups and thiol groups and arbitrary combinations of two or more thereof with a2) at least one α,Β-unsaturated carboxylic acid comprising two or more carboxylic groups and/or at least one anhydride thereof so as to obtain a first reaction product, b) reacting b1) the first reaction product with b2) at least one rosin acid containing at least two conjugated double bonds so as to obtain a second reaction product, c) reacting C1) the second reaction product with C2) at least one amine compound comprising two or more primary and/or secondary amine groups so as to obtain a third reaction product, d) reacting d1) the third reaction product with d2) at least one epoxy compound so as to obtain the polymer, wherein the polymer does not contain any terminal vinyl groups, does not contain any terminal acrylic and does not contain any terminal methacrylic group.