Terpolymer Pipe Composition for Impact and Hydrostatic Resistance
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Solution Overview
Problem
There is a need for a polypropylene-based terpolymer composition that offers high impact resistance and hydrostatic pressure resistance for pipes, particularly for hot and cold water pressure pipes, which are prone to brittle failure at elevated temperatures and require improved handling and installation properties.
Innovation Solution
A polypropylene composition comprising a terpolymer of propylene, ethylene, and 1-hexene, combined with a nucleating agent such as a metal salt of hexahydrophthalic acid, and optionally pigments, which provides a balance of impact resistance and pressure resistance, allowing for higher extrusion speeds and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polypropylene compositions are used for pipes, then basic structural integrity is maintained, but impact resistance and hydrostatic pressure resistance are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the comonomer composition (ethylene content: 0.5-5.0 wt%, 1-hexene content: 0.1-3.0 wt%) and molecular weight distribution (Mw/Mn ratio: 3.0-15.0) of the terpolymer. These parameter optimizations enable the polymer to achieve both high impact resistance and delayed brittle failure without compromising structural integrity
Solution Approach 2:
The patent creates a composite material system by combining the propylene/ethylene/1-hexene terpolymer with specific additives including nucleating agents (0.01-1.0 wt%), antioxidants (0.1-5.0 wt%), and processing aids (0.1-5.0 wt%). This composite approach synergistically enhances both impact resistance and long-term reliability against brittle failure
2Strength
If conventional polypropylene compositions are used for pipes, then basic pressure resistance is maintained, but hydrostatic pressure resistance at elevated temperatures is insufficient
Solution Approach 1:
The patent optimizes thermal performance parameters by controlling the terpolymer's comonomer content (ethylene: 0.5-5.0 wt%, 1-hexene: 0.1-3.0 wt%) and molecular weight distribution (Mw/Mn: 3.0-15.0), which enhances hydrostatic pressure resistance at elevated temperatures while maintaining structural stability
Solution Approach 2:
The patent employs small amounts of functional additives (nucleating agents: 0.01-1.0 wt%, antioxidants: 0.1-5.0 wt%) that provide temporary but effective thermal stabilization during service, allowing the pipe to maintain pressure resistance at elevated temperatures throughout its service life
3Productivity
If conventional polypropylene compositions are used for pipes, then basic processability is achieved, but extrusion speed is limited
Solution Approach 1:
The patent improves processability and extrusion speed by optimizing the terpolymer's molecular weight distribution (Mw/Mn ratio: 3.0-15.0) and comonomer content, which enhances melt flow characteristics and reduces processing energy requirements
Solution Approach 2:
The patent introduces processing aids (0.1-5.0 wt%) as intermediary substances that facilitate polymer chain separation and reduce friction during extrusion, enabling higher extrusion speeds while maintaining good processability and surface quality
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 composition results in pipes with enhanced impact resistance, extended time to brittle failure, and improved hydrostatic pressure resistance, enabling higher throughput and energy efficiency in production, while maintaining environmental and cost benefits.
Implementation Method 1
the nucleating agent (B) is a nucleating agent comprising a metal salt of hexahydrophthalic acid represented by formula (I)
Data Source
AI summary
The invention relates to a pipe comprising a polypropylene composition (P) comprising a terpolymer composition (A), a nucleating agent (B) and optionally a composition comprising pigment (C), wherein the terpolymer composition (A) comprises at least one terpolymer prepared from propylene, ethylene and 1-hexene, wherein the nucleating agent (B) is a nucleating agent comprising a metal salt of hexahydrophthalic acid represented by formula (I) (I) wherein M1 and M2 are the same or different, and may be combined into one cation, and are selected from at least one metal cation of calcium, strontium, lithium, and monobasic aluminum; and wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are either the same or different and are individually selected from the group consisting of hydrogen, C1-C9 alkyl, hydroxy, C1-C9alkoxy, C1-C9 alkyleneoxy, amine, and C1-C9 alkylamine, halogens, and phenyl wherein the polypropylene composition (P) has a melt flow rate in the range from 0.10 to 0.70 dg/min as determined by ISO1133-1:2011 at 230° C. and 2.16 kg.