Ethylene-Vinyl Alcohol Copolymer Adhesive Coating
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Solution Overview
Problem
Existing adhesives based on polyvinyl alcohol (PVA) face challenges in achieving high-speed coating ability while maintaining water-resistant adhesiveness, often resulting in coating irregularities, stringing, and contamination due to poor solution stability and water-resistant adhesiveness.
Innovation Solution
An ethylene-vinyl alcohol copolymer with a specific block character of ethylene units (0.90 to 0.99) and a viscosity-average polymerization degree of 200 to 5000, produced by reacting ethylene with a vinyl ester and subsequent saponification, is used to create an adhesive with improved high-speed coating and water-resistant properties, incorporating a compound with a conjugated double bond and an inorganic filler for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If PVA adhesive is used to improve water-resistant adhesiveness, then solution stability deteriorates and coating ability worsens
Solution Approach 1:
The patent uses a composite material system consisting of PVA as the base polymer and clay particles as reinforcing filler. The clay particles (bivalent or more metal salts of sulfuric acid) form a network structure within the PVA matrix, creating a composite that simultaneously improves water resistance and maintains solution stability. This composite approach allows the adhesive to achieve both improved adhesiveness and coating ability without the drawbacks of pure PVA modifications.
2Productivity
If coating speed is increased to improve productivity, then coating irregularity increases and adhesive quality deteriorates
Solution Approach 1:
The patent modifies the rheological parameters of the adhesive by incorporating clay particles, which change the flow characteristics and viscosity behavior of the adhesive solution. This parameter modification allows the adhesive to maintain uniform coating even at high coating speeds, preventing stripe formation and coating irregularities that normally occur when coating speed increases.
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 ethylene-vinyl alcohol copolymer achieves excellent high-speed coating ability and water-resistant adhesiveness, addressing the limitations of previous PVA-based adhesives by controlling the block character and incorporating additives for improved stability and application performance.
Implementation Method 1
reacting ethylene with a vinyl ester to give an ethylene-vinyl ester copolymer and then saponifying the ethylene-vinyl ester copolymer
Data Source
AI summary
An ethylene-vinyl alcohol copolymer may have an ethylene unit content of 1 mol % or more and less than 20 mol %, a viscosity-average polymerization degree of 200 to 5000 and a saponification degree of 80 to 99.7 mol %. A block character of ethylene units in the ethylene-vinyl alcohol copolymer may be 0.90 to 0.99. Such an ethylene-vinyl alcohol copolymer may have excellent high-speed coating ability and water-resistant adhesiveness, particularly when being used as an adhesive.