Vinyl Alcohol Polymer Side Chain Segmentation for Stability
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Solution Overview
Problem
Vinyl alcohol-based polymers with olefins in side chains face issues with storage stability, solubility in water or organic solvents, and reactivity to high-energy beams due to reactive functional groups leading to cross-linking and gelation, and existing modifications either result in insolubilization or hydrophobic structures that are not suitable for various applications.
Innovation Solution
A vinyl alcohol-based polymer with a specific structural unit having an olefin in the side chain, comprising a divalent aliphatic, alicyclic, or aromatic hydrocarbon group linked via amide, ester, ether, or sulfide bonds, which is introduced through addition-reacting a vinyl alcohol-based polymer with an amine compound, ensuring stability and reactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an α,β-unsaturated olefin (acrylate, methacrylate, or acrylamide group) is introduced into the side chain of a vinyl alcohol-based polymer, then the polymer can be made water-resistant through high-energy beam crosslinking, but the functional groups mutually cross-link during storage, resulting in an insolubilized polymer with poor storage stability
Solution Approach 1:
The patent divides the olefin functional group into two separate segments: the reactive C=C double bond is separated from the polar carbonyl or amide group by introducing a methylene bridge or alkylene chain. This segmentation prevents the polar groups from interacting and cross-linking during storage, while still maintaining the reactivity of the C=C bond for subsequent crosslinking reactions to achieve water resistance.
Solution Approach 2:
The patent introduces a methylene bridge or alkylene chain as an intermediary structure between the olefinic C=C bond and the polar functional group. This intermediary spacer prevents direct interaction between polar groups that would cause premature crosslinking, while allowing the C=C bond to remain accessible for high-energy beam crosslinking to achieve water resistance.
2Reliability
If a hydrophobic structure is introduced into the side chain of a vinyl alcohol-based polymer, then the polymer may achieve water resistance, but the polymer tends to gelate during the manufacturing process, resulting in poor stability
Solution Approach 1:
The patent applies local quality by introducing a hydrophobic alkylene chain only in the spacer region between the polar functional group and the olefinic bond, while maintaining the overall hydrophilic character of the polymer through the vinyl alcohol backbone and polar groups. This localized hydrophobicity provides water resistance without causing bulk gelation during manufacturing.
Solution Approach 2:
The patent controls the length of the alkylene chain spacer (typically 1-4 carbon atoms) to optimize the balance between water resistance and manufacturing stability. By adjusting this parameter, the polymer achieves sufficient hydrophobicity for water resistance while maintaining adequate solubility and preventing gelation during processing.
3Strength
If a vinyl alcohol-based polymer with high hydrophilicity is used, then excellent film properties (strength, oil resistance, film-formability, oxygen gas barrier properties) are achieved, but the physical properties deteriorate significantly under high humidity conditions
Solution Approach 1:
The patent creates a composite structure at the molecular level by combining the hydrophilic vinyl alcohol backbone (providing film strength and barrier properties) with hydrophobic side chains containing olefin groups (providing water resistance). This composite architecture allows the polymer to maintain excellent film properties while resisting water penetration under high humidity conditions.
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 exhibits excellent storage stability, high solubility in water or organic solvents after thermal treatment, and enhanced reactivity to high-energy beams, making it suitable for diverse applications such as coatings and adhesives.
Implementation Method 1
comprising addition-reacting a vinyl alcohol-based polymer with an amine compound
Implementation Method 2
allowing for making the polymer water-resistant by high-energy beam crosslinking
Data Source
AI summary
There is provided a vinyl alcohol-based polymer having an olefin in side chain, comprising 0.001 to 10 mol % of a structural unit represented by Formula (1) based on the total amount of structural units, wherein the total carbon number of X, R1, R2, R3 and R4 is 2 or more. The vinyl alcohol-based polymer having an olefin in side chain has excellent storage stability, good solubility in water or an organic solvent even after thermal treatment, and excellent reactivity to high energy beam. In Formula (1), X represents an optionally substituted divalent aliphatic hydrocarbon group, an optionally substituted divalent alicyclic hydrocarbon group, an optionally substituted divalent aromatic hydrocarbon group, or a group consisting of two or more of these groups which are linked via at least one bond selected from the group consisting of an amide bond, an ester bond, an ether bond, and a sulfide bond; R1, R2, R3 and R4, independently of each other, represents a hydrogen atom, an optionally substituted aliphatic hydrocarbon group, an optionally substituted alicyclic hydrocarbon group, or an optionally substituted aromatic hydrocarbon group; and X, R1, R2, R3 and R4 can be arbitrarily combined to form a ring structure).