Polypropylene Copolymer Composition for ISBM Articles
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Solution Overview
Problem
Polypropylene (PP) based injection stretch blow-molded (ISBM) articles face challenges with long cycle times and opacity, making them less suitable for applications requiring high temperature resistance and transparency compared to polyethylene terephthalate (PET).
Innovation Solution
A polypropylene copolymer composition with an ethylene content of 2.0 to 5.0 wt% and specific crystallization temperatures is used, combined with a nucleating agent, to enhance the processability and optical properties of ISBM articles, allowing for shorter cycle times and improved transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If polypropylene is used in ISBM processes to achieve better heat resistance and lower cost, then heat resistance and cost-effectiveness are improved, but cycle time increases and transparency deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the polypropylene copolymer by controlling ethylene content (2.0-5.0 wt%) and creating specific fraction distributions (first fraction: 40-59 wt% with 0.0-1.8 wt% comonomer, second fraction: 60-41 wt%). This parameter optimization enables the material to crystallize faster at lower temperatures, thereby reducing the cycle time while preserving heat resistance.
Solution Approach 2:
The invention creates a composite polypropylene copolymer system consisting of two distinct fractions with different comonomer contents and crystallization behaviors. The first fraction (lower comonomer content) provides structural integrity and heat resistance, while the second fraction (higher comonomer content) enhances processability and cooling rate. This composite structure resolves the contradiction between heat resistance and cycle time.
2Temperature
If polypropylene is used in ISBM processes to achieve better heat resistance and lower cost, then heat resistance and cost-effectiveness are improved, but transparency deteriorates
Solution Approach 1:
The invention optimizes the comonomer content parameter within a narrow range (2.0-5.0 wt% ethylene) and controls the molecular weight distribution through specific fraction ratios. These parameter changes result in a crystalline structure that allows light transmission while maintaining the heat resistance characteristics of polypropylene, thus improving transparency without sacrificing thermal performance.
Solution Approach 2:
The dual-fraction copolymer structure creates a composite material where the first fraction (40-59 wt%) provides heat resistance and the second fraction (60-41 wt%) with higher comonomer content improves optical clarity. The synergistic combination of these two fractions resolves the contradiction between heat resistance and transparency.
3Ease of manufacture
If conventional polypropylene copolymers are used to reduce production cost, then cost-effectiveness is improved, but production efficiency deteriorates
Solution Approach 1:
The invention changes the compositional parameters of the polypropylene copolymer by precisely controlling ethylene content (2.0-5.0 wt%) and creating a specific bimodal distribution with defined fraction ratios. These parameter optimizations improve the material's flow and cooling characteristics during injection stretch blow moulding, thereby increasing production efficiency while maintaining cost-effectiveness through continued use of polypropylene rather than more expensive alternatives like PET.
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 polypropylene copolymer composition results in ISBM articles with reduced cycle times, improved transparency, and enhanced optical properties, making them more suitable for high-temperature applications while maintaining production efficiency and reducing energy consumption.
Implementation Method 1
a crystallisation temperature (Tc) of at least 90°C when subjected to a cooling rate of 10 K/s; a crystallisation temperature (Tc) of at least 55°C when subjected to a cooling rate of 100 K/s; and a crystallisation temperature (Tc) of at least 40°C when subjected to a cooling rate of 300 K/s
Implementation Method 2
(II) optionally at least one nucleating agent
Data Source
AI summary
An injection stretch blow moulded article (ISBM) comprising: (I) a polypropylene copolymer composition having an ethylene content of 2.0 to 5.0 wt%; and a crystallisation temperature (Tc) of at least 90°C when subjected to a cooling rate of 10 K/s; a crystallisation temperature (Tc) of at least 55°C when subjected to a cooling rate of 100 K/s; and a crystallisation temperature (Tc) of at least 40°C when subjected to a cooling rate of 300 K/s; and (II) optionally at least one nucleating agent.