Ethylene-Modified Vinyl Alcohol Resin for Stable Adhesive Viscosity
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Solution Overview
Problem
Existing ethylene-vinyl alcohol copolymers suffer from inadequate hue and aqueous-solution viscosity stability, and adhesives using them lack high-speed coatability for industrial applications.
Innovation Solution
A resin material comprising an ethylene-modified vinyl alcohol polymer with specific ethylene unit content, viscosity-average degree of polymerization, degree of saponification, and propyl group content, along with sodium acetate, enhances hue and aqueous-solution viscosity stability, and includes a compound with a conjugated double bond for improved coatability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ethylene-vinyl alcohol copolymer is used to improve water solubility, then water solubility is improved, but hue and aqueous-solution viscosity stability deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ethylene unit content (1-14 mol%), viscosity-average degree of polymerization (200-3,000), degree of saponification (80-99.9 mol%), and propyl group content (0.0005-0.10 mol%). These parameter optimizations resolve the contradiction by finding the optimal balance point where water solubility is maintained while hue and viscosity stability are significantly improved compared to conventional copolymers.
Solution Approach 2:
The patent creates a composite material system by combining ethylene-modified vinyl alcohol polymer with specific additives including sodium acetate (0.05-2.0 mass%), compounds with conjugated double bonds (0.000001-0.01 parts by mass), and other auxiliary agents. This composite approach enables simultaneous achievement of water solubility, excellent hue, and viscosity stability that cannot be obtained by the copolymer alone.
2Device complexity
If conventional ethylene-vinyl alcohol copolymer is used to simplify adhesive formulation, then formulation complexity is reduced, but high-speed coatability deteriorates
Solution Approach 1:
The patent optimizes the viscosity-average degree of polymerization (200-3,000) and molecular weight characteristics of the ethylene-modified vinyl alcohol polymer to achieve optimal flow properties for high-speed coatability. The controlled propyl group content (0.0005-0.10 mol%) also contributes to improved coating performance by modifying polymer chain conformation and intermolecular interactions.
Solution Approach 2:
The patent introduces compounds with conjugated double bonds (0.000001-0.01 parts by mass) as intermediary substances that act as processing aids. These compounds improve high-speed coatability by modifying the rheological properties of the adhesive formulation and reducing surface tension, enabling smooth application at high speeds without increasing formulation complexity.
3Adaptability or versatility
If PVA aqueous solution undergoes large viscosity changes, then processing flexibility is improved, but film property uniformity deteriorates
Solution Approach 1:
The patent controls the degree of saponification (80-99.9 mol%) and ethylene unit content (1-14 mol%) to achieve a balanced viscosity profile that maintains processing flexibility while ensuring film uniformity. The optimized viscosity-average degree of polymerization (200-3,000) provides appropriate shear-thinning behavior for easy processing without causing excessive viscosity variations during film formation.
Solution Approach 2:
The patent formulates a composite aqueous solution containing the ethylene-modified vinyl alcohol polymer combined with sodium acetate (0.05-2.0 mass%), compounds with conjugated double bonds, and other additives. This composite formulation buffers viscosity changes during processing, maintaining both processing flexibility and film property uniformity by creating a more stable rheological system.
Data Source
Figure 1
AI summary
The present invention provides a resin material that comprises an ethylene-modified vinyl alcohol polymer as a main component, and that excels in hue, water solubility, and aqueous-solution viscosity stability. The present invention also provides an aqueous solution and an adhesive comprising such a resin material. The present invention relates to a resin material comprising an ethylene-modified vinyl alcohol polymer and sodium acetate, wherein: the ethylene-modified vinyl alcohol polymer has an ethylene unit content of 1 mol% or more and less than 15 mol%, a viscosity-average degree of polymerization of 200 or more and less than 3,000, and a degree of saponification of 80 mol% or more and less than 99.9 mol%, and comprises 0.0005 mol% or more and 0.10 mol% or less of a propyl group at one end of the polymer, and the sodium acetate content is 0.05 mass% or more and less than 2 mass%.