PVDF Homopolymer and Fluorocopolymer Blend for Pipe Toughness
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Solution Overview
Problem
Existing polymeric compositions for offshore oil industry pipes face challenges with mechanical, thermal, and chemical resistance, particularly at high temperatures and pressures, and suffer from flexibility and toughness loss due to plasticizer extraction, while also requiring moderate viscosity for processing and avoiding resin sag during manufacturing.
Innovation Solution
A polymeric composition combining a PVDF homopolymer with a thermoplastic fluorocopolymer and minimal plasticizer content, optimized for high molecular weight impact properties, moderate melt viscosity, and low ductile-brittle transition temperature, allowing for improved toughness and processability without significant viscosity increase or property loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polymeric compositions are plasticized to improve flexibility and toughness, then mechanical properties at low temperature are improved, but plasticizers are extracted by hydrocarbons leading to progressive loss of flexibility and toughness
Solution Approach 1:
The invention removes plasticizers from the polymeric composition entirely, replacing them with a blend of PVDF homopolymer and VF2 copolymer that provides the required flexibility and toughness without extraction issues. This eliminates the harmful extraction effect while maintaining the desired mechanical properties.
Solution Approach 2:
The invention uses a composite polymeric composition combining PVDF homopolymer and VF2 copolymer in specific proportions (60-90 wt% PVDF, 10-40 wt% VF2 copolymer). This composite approach achieves the required toughness and flexibility through synergistic interaction of the two polymers without requiring plasticizers.
2Ease of manufacture
If polymeric compositions have low viscosity for easy processing, then processability is improved, but resin sags into gaps between spiralled tape turns during manufacture
Solution Approach 1:
The invention optimizes the viscosity parameter of the polymeric composition by controlling the ratio of PVDF homopolymer to VF2 copolymer and selecting appropriate molecular weights. This achieves a balanced viscosity that allows proper processing while preventing resin sag into gaps during pipe manufacturing.
Data Source
AI summary
Polymeric composition based on a PVDF homopolymer and a thermoplastic fluorocopolymer Polymeric composition based on a PVDF homopolymer and a thermoplastic fluoropolymer offering an improved toughness/processability compromise, possessing an apparent melt viscosity not exceeding 60 000 Pa·s at a shear rate of 1 s−1, a ductile-brittle transition temperature below +5° C. and a weight loss in air at 150° C. of 5% or less. Pipes and fashioned articles prepared from this composition.