Pigmented GRP Pipe Liner Structure for Impact and Pressure Resistance

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Solution Overview

Problem

Glass fibre reinforced pipes (GRP) are sensitive to impact damage and pigmentation in unsaturated polyester resin liners interferes with mechanical performance, reducing resistance to internal pressure and hydrostatic design basis testing.

Innovation Solution

A glass-reinforced plastic pipe liner with layers of non-woven fibres and chopped fibre strands formed from unsaturated polyester resin, optionally mixed with vinyl ester resin, and incorporating colour pigments at 0.2 - 5.0 wt%, which improves impact performance, abrasion resistance, and allows for pigmentation without compromising mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If pigments are added to unsaturated polyester resin liners, then the liner can be pigmented for identification purposes, but the mechanical performance and resistance to internal pressure are reduced

Engineering Contradiction:
Improvepigmentation capabilityVSAvoidmechanical performance and resistance to internal pressure
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The liner is divided into multiple functional layers: an outer flexible liner layer containing pigments for identification, and an inner structural reinforcement layer free of pigments to maintain mechanical strength. This segmentation allows each layer to fulfill its specific function without compromise.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the liner have different compositions: the outer layer contains pigments for identification while the inner layer remains pigment-free to preserve mechanical properties. This local differentiation of material quality resolves the contradiction between pigmentation and strength.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3216593B1Liner for impact resistant GRP pipes
Publication Date: 2021.02.17 AMIBLU TECH AS

AI summary

The invention relates to a glass-reinforced plastic pipe liner of improved impact performance comprising layer B) from unsaturated polyester resin, optionally mixed with vinyl ester resin reinforced by non-woven fibres and a layer C) from unsaturated polyester resin, optionally mixed with vinyl ester resin reinforced by chopped fibre strands. At least one of these layers B) or C) comprises colour pigments at 0.2 - 5.0 wt%. The invention provides flexible liners for pressure and non-pressure GRP pipes. It improves impact performance of the pipe liner whilst offering also improvements in abrasion resistance, water-jet resistance for high pressure cleaning without liner damage, increased expected lifetime by improved resistance to internal pressure and permits pigmentation of the liner. The invention also encloses a process for producing the glass-reinforced plastic pipe liner.