Ethylene Polymer Viscosity Stability via Rosin Ester Crosslinking
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Solution Overview
Problem
Ethylene polymers derived from polar monomers with ester groups exhibit limited viscosity stability at elevated temperatures, leading to degradation and char particle formation in hot-melt adhesive formulations, which affects adhesive quality and equipment performance.
Innovation Solution
Incorporating a rosin ester with specific properties, such as low hydroxyl and acid numbers, into ethylene polymers derived from polar monomers, which polymerize with ethylene, to enhance viscosity stability and reduce char formation at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ethylene polymers derived from polar monomers with ester groups are processed at elevated temperatures, then adhesive bonding is achieved, but viscosity stability deteriorates leading to degradation and char particle formation
Solution Approach 1:
The patent introduces a rosin ester as an intermediary substance that mediates between the ethylene polymer and the thermal degradation process. The rosin ester reacts with the polymer to form a stable crosslinked structure that prevents direct thermal degradation and char formation, while maintaining the adhesive bonding function at elevated temperatures
Solution Approach 2:
The patent creates a composite material system combining ethylene polymer with rosin ester and potentially other additives. This composite structure provides both the adhesive bonding properties of the polymer and the thermal stability of the rosin ester crosslinked network, preventing viscosity degradation and char particle formation during processing
2Reliability
If ethylene copolymers are used in hot-melt adhesive formulations, then adhesion to substrates is achieved, but equipment downtime increases due to nozzle obstruction from char particles
Solution Approach 1:
The patent converts the potentially harmful thermal degradation pathway into a beneficial crosslinking process. The rosin ester reacts with the ethylene polymer chains during processing, creating a stable crosslinked structure that prevents char particle formation. This transforms what would be a degradation mechanism into a protective crosslinking mechanism that eliminates nozzle obstruction and equipment downtime
3Stability of the object's composition
If rosin ester is incorporated into ethylene polymer compositions, then viscosity stability is improved, but formulation complexity increases
Solution Approach 1:
The patent optimizes specific parameters of the rosin ester (such as molecular weight, hydroxyl value, and acid value) to achieve effective crosslinking with minimal additives. By carefully selecting and controlling these parameters, the formulation achieves viscosity stability through the rosin ester alone, avoiding the need for multiple stabilizing agents and simplifying the overall formulation
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 compositions exhibit improved viscosity stability and reduced char formation, maintaining adhesive quality and preventing equipment obstruction, with less than 10% change in viscosity and minimal char formation after thermal aging.
Implementation Method 1
By stabilizing the viscosity of ethylene polymers derived from at least one polar monomer with one or more ester groups, which polymerize with ethylene (e.g., copolymers derived from ethylene and vinyl acetate or n-butyl acrylate) at elevated temperatures in hot-melt adhesive formulations, the processing of such materials can be greatly improved.
Implementation Method 2
At elevated temperatures, they can degrade, leading to crosslinking of the copolymer and an increase in viscosity.
Data Source
AI summary
Disclosed are compositions which include an ethylene polymer derived from at least one polar monomer with one or more ester groups, which polymerize with ethylene, (e.g., a copolymer derived from ethylene and vinyl acetate or a copolymer derived from ethylene and n-butyl acrylate) and a rosin ester. The rosin ester can have a low hydroxyl number (e.g., a hydroxyl number six or five or less), a low acid number (e.g., an acid number of ten or less), a low PAN number (e.g., a PAN number of eight or less), or combinations thereof. The compositions can exhibit improved viscosity stability and/or color stability and/or a decreased amount of char particle formation upon thermal aging.