Ethylene-Acrylic Acid Copolymer for Long-Lasting Adhesion
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Solution Overview
Problem
Conventional ethylene-acrylic acid copolymers suffer from a limitation in maintaining adhesive strength over time, necessitating improved long-term adhesive properties for applications in packaging materials.
Innovation Solution
The ethylene-acrylic acid copolymer is formulated with specific properties including zero shear viscosity (η0) of 3,800 Pa·s or more and storage modulus (G′) of 90 Pa or more at a loss modulus (G″) of 500 Pa, along with controlled molecular weights and acrylic acid content, achieved through high-temperature and high-pressure polymerization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ethylene-acrylic acid copolymer is used as adhesive, then initial adhesive strength is excellent, but adhesive strength deteriorates over time
Solution Approach 1:
The patent applies parameter changes by precisely controlling the zero shear viscosity (η0 ≥ 3,800 Pa·s) and storage modulus (G′ ≥ 90 Pa at G″ = 500 Pa) of the copolymer. These rheological parameter specifications ensure the adhesive maintains both initial bonding strength and long-term durability by optimizing the balance between flow properties during application and structural stability during service.
Solution Approach 2:
The invention uses ethylene-acrylic acid copolymer as a composite material system where the specific composition ratio (1-30 wt% acrylic acid units) and molecular weight distribution (Mw/Mn ≥ 6, Mz/Mw ≥ 3.9) create a material that combines the benefits of both monomers while achieving superior long-term adhesive performance through controlled molecular architecture.
2Quantity of substance
If high pressure free radical copolymerization system is used, then copolymer can be produced, but high pressure equipment and advanced technology are required
Solution Approach 1:
The patent specifies precise polymerization parameters including temperature range (150-350°C) and pressure range (1,000-5,000 bar) to optimize the copolymerization process. By defining these parameter ranges, the invention enables production of copolymer with target molecular weight distribution and rheological properties while providing guidance for equipment selection and process design.
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 copolymer maintains high initial adhesive properties for an extended period, demonstrating improved long-term adhesive strength, particularly in laminated sheets under harsh conditions.
Implementation Method 1
copolymerization of an ethylene monomer and a carboxylic acid monomer uses a high pressure free radical copolymerization system
Data Source
AI summary
Provided is an ethylene-acrylic acid copolymer which may maintain high initial adhesive properties for a long time by having a zero shear viscosity (η0) and a storage modulus (G′) in specific ranges.