Ethylene/alpha-olefin copolymer bubble stability
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Solution Overview
Problem
Existing polyethylene films face challenges with bubble instability during the film blowing process, leading to unsatisfactory melt elasticity and viscosity issues, which affect the quality and stability of the final product.
Innovation Solution
An ethylene/alpha-olefin copolymer is synthesized in a fluidized-bed, gas phase polymerization reactor with specific operating conditions, including a controlled reactor bed temperature and H2/C2 gas molar ratio, resulting in a blown film with enhanced bubble stability characterized by a melt storage modulus of 3,000 Pa, density between 0.947 and 0.954 g/cm³, and a melt flow ratio of 20.5 to 24.4.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polyethylene films are used in film blowing process, then production can proceed with standard equipment and procedures, but bubble instability occurs leading to poor film quality
Solution Approach 1:
The patent applies parameter changes by precisely controlling polymerization conditions (reactor bed temperature, H2/C2 gas molar ratio) to achieve specific copolymer properties (density, melt flow ratio, melt storage modulus) that resolve the bubble stability issue while maintaining manufacturing feasibility
Solution Approach 2:
The patent uses composite materials by creating an ethylene/alpha-olefin copolymer with specific compositional characteristics (density 0.947-0.954 g/cm³, melt flow ratio 20.5-24.4) that combines the benefits of polyethylene with alpha-olefin comonomer to achieve enhanced bubble stability
2Reliability
If internal bubble cooling (IBC) is used to stabilize the bubble, then bubble stability improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts the bubble stability function from the processing equipment (removing the need for IBC system) and embeds it directly into the polymer material itself through specific compositional design, thereby eliminating complex cooling equipment while maintaining bubble stability
Solution Approach 2:
The copolymer resin serves itself by providing inherent bubble stability through its material properties (melt storage modulus, density, melt flow ratio) without requiring external active cooling systems, enabling passive bubble stabilization
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 solution effectively increases bubble stability and reduces instability in the blown film, allowing for the production of films without internal bubble cooling and enabling the use of various additives, thereby improving the film's mechanical properties and manufacturing process.
Implementation Method 1
ethylene/alpha-olefin copolymer that can be synthesized in a fluidized-bed, gas phase polymerization (FB-GPP) reactor
Implementation Method 2
fluidized-bed, gas phase polymerization (FB-GPP) reactor
Implementation Method 3
melt storage modulus G' (G"=3,000 Pa), and melt flow ratio (I21/I5)
Data Source
AI summary
An ethylene/alpha-olefin copolymer that can be synthesized in a fluidized-bed, gas phase polymerization reactor and made into a blown film. The ethylene/alpha-olefin copolymer is characterized by a bubble stability-effective combination of properties comprising density, melt flow ratio ("I21/I5"), and melt storage modulus G' (G"=3,000 Pa). The synthesis in the FB-GPP reactor is characterized by a property-imparting-effective combination of operating conditions comprising reactor bed temperature and H2/C2 gas molar ratio. An embodiment of the blown film consisting of the ethylene/alpha-olefin copolymer is characterized by enhanced bubble stability. A method of making the ethylene/alpha-olefin copolymer. A film comprising the ethylene/alpha-olefin copolymer. A method of making the film. A manufactured article comprising the film.