PVA Resin Yellowing Suppression via Chlorine Extraction
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Solution Overview
Problem
Polyvinyl alcohol-based resins containing sulfonic acid or base exhibit yellowing when heated, which is not adequately addressed in existing technologies.
Innovation Solution
A resin composition with a reduced chlorine content, specifically 0.001 to 0.05 parts by mass of chlorine atoms per 100 parts by mass of polyvinyl alcohol-based resin, is developed to suppress yellowing by minimizing the chlorine component, which acts as a catalyst for double bond formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PVA-based resin containing sulfonic acid or base is used as a dispersant or coating liquid, then dispersion performance and water-solubility are improved, but yellowing occurs when heated at high temperatures
Solution Approach 1:
The invention extracts and removes the harmful chlorine component from the PVA-based resin system. By specifically targeting and eliminating chlorine (reducing to 0.001-0.05 parts by mass per 100 parts resin), the yellowing catalyst is removed while preserving the beneficial sulfonic acid groups and overall resin structure for maintaining dispersion performance.
Solution Approach 2:
The invention changes the chlorine content parameter from conventional levels to an ultra-low range (0.001-0.05 parts by mass per 100 parts resin). This parameter modification fundamentally alters the thermal stability and color stability of the resin system, preventing yellowing while maintaining other functional properties.
2Object-affected harmful factors
If chlorine content is reduced to suppress yellowing, then color stability at high temperature is improved, but manufacturing complexity increases due to additional purification steps
Solution Approach 1:
The invention performs preliminary action by removing the chlorine component during the polymerization or resin synthesis stage, before the resin is fully formed and before application. This early removal prevents chlorine from causing yellowing during subsequent high-temperature processing, and allows for simpler final resin processing since the harmful component is already eliminated.
Solution Approach 2:
The invention uses an intermediary substance or process (such as washing with water or alcohol, or using ion-exchange resins) to selectively remove chlorine from the PVA-based resin system. These intermediary steps facilitate chlorine removal without requiring complete redesign of the manufacturing process.
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 resin composition exhibits minimal yellowing even at high temperatures, maintaining whiteness and transparency, making it suitable for applications like heat-sensitive color-forming layers and films.
Implementation Method 1
minimizing the chlorine component, which acts as a catalyst for double bond formation
Data Source
AI summary
To provide a resin composition comprising a PVA-based resin containing a sulfonic acid or base thereof in which coloring (yellowing) of the PVA-based resin at a high temperature is suppressed so that coloring (yellowing) of the resin composition is decreased even under a high temperature environment. The resin composition of the invention comprises a polyvinyl alcohol-based resin containing sulfonic acid or base thereof (A) and a chlorine component (B), in which a content of the chlorine component (B) is 0.1 part by mass or less in terms of chlorine atom with respect to 100 parts by mass of the polyvinyl alcohol-based resin containing sulfonic acid or base thereof (A).