Recycled PET Adhesive Repair Patches for Anti-Corrosive Coatings

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Solution Overview

Problem

Current methods for repairing corrosion-damaged painting systems on carbon steel are costly, time-consuming, and prone to premature degradation due to operational errors and difficult access, while recycled polyethylene terephthalate (PET) is often discarded without effective reuse, contributing to environmental issues.

Innovation Solution

A process is developed to produce an anti-corrosive adhesive repair system using recycled PET, involving dissolution of PET flakes in a strong carboxylic acid and organic solvent, addition of a plasticizer, phase inversion, and application with a tacky glue, resulting in a flexible, impermeable film for temporary protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional repair methods are used for corrosion-damaged painting systems, then the protection is restored, but the process is costly and time-consuming

Engineering Contradiction:
Improvecorrosion protectionVSAvoidrepair execution time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent employs disposable adhesive tapes impregnated with thermoplastic resin that can be directly applied to damaged areas. These tapes provide temporary corrosion protection without requiring complex preparation or specialized application equipment, enabling quick repair execution while maintaining reliable protection during the service period.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention extracts the essential protective function from complex conventional repair systems and isolates it into a simple adhesive tape formulation. By separating the adhesive, thermoplastic resin, and protective coating into a pre-integrated tape product, the solution eliminates the need for multiple sequential steps including surface preparation, primer application, and topcoat painting.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If conventional repair methods are used for corrosion-damaged painting systems, then the protection is restored, but the cost increases due to quality inputs and qualified labor

Engineering Contradiction:
Improvecorrosion protectionVSAvoidrepair cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The adhesive tape is designed as an inexpensive, disposable product that eliminates the need for expensive specialized labor and materials. The tape can be applied by untrained personnel without specialized equipment, significantly reducing both material and labor costs while maintaining adequate corrosion protection for the intended service life.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The adhesive tape is designed to be self-applied without requiring skilled labor or specialized equipment. The tape's adhesive backing allows direct application to prepared surfaces, and the thermoplastic resin provides self-leveling and self-bonding properties, enabling anyone to perform the repair without professional training.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If recycled PET is discarded without reuse, then disposal is simple, but environmental problems arise

Engineering Contradiction:
Improvedisposal simplicityVSAvoidenvironmental impact
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent recovers discarded PET bottles by collecting, cleaning, and processing them into flake form. This recovered PET material is then used as the base resin in the adhesive tape formulation, transforming waste material into a valuable protective coating product and eliminating environmental disposal problems.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The invention converts the harmful environmental factor of PET waste into a beneficial resource. By using discarded PET bottles as the primary resin source for the adhesive tape, the process transforms environmental pollution into a useful protective coating material, simultaneously solving both waste management and corrosion protection needs.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of manufacture

If the adhesive film is made from recycled PET, then cost decreases and environment is helped, but manufacturing complexity increases

Engineering Contradiction:
Improveobtention costVSAvoidmanufacturing process
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The manufacturing process utilizes parameter changes to simplify production. The thermoplastic resin is dissolved in a solvent to create a aplicable solution, then the solvent is evaporated to leave the adhesive film. This phase change approach allows simple batch processing without complex extrusion or molding equipment, maintaining low cost while managing the recycled material.

Inventive Principle:
Principle #35Parameter changes

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 adhesive film provides effective corrosion prevention with low permeability and chemical resistance, reducing costs and environmental impact by utilizing recycled PET, with a durability of at least 2 years.

Implementation Method 1

dissolving the flakes in a proportion of 15% to 35% (m/v) in a solution containing a strong carboxylic acid and an organic solvent in the range of 5/95 (% v/v) to 95/5 (% v/v) acid/solvent

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

performing the phase inversion technique by submerging the glassy plate in a non-solvent bath of distilled water

Methodology Applied
Scientific EffectPhase inversion: Phase Change

Implementation Method 3

waiting for the partial precipitation of the thermoplastic material

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 4

the use of appropriate chemical products are necessary... the barrier formed must be impermeable to these agents

Methodology Applied
Scientific EffectBarrier formation: Adsorption

Data Source

PatentEP4628558A1Polyethylene terephthalate-based adhesive repair patch for Anti-corrosive coatings, method for producing same and use thereof
Publication Date: 2025.10.08 PETROLEO BRASILEIRO SA PETROBRAS
  • EP4628558A1 patent drawingFigure 1~2b
  • EP4628558A1 patent drawingFigure 3
  • EP4628558A1 patent drawingFigure 4a~4b

AI summary

The present invention relates to the process of obtaining an anti-corrosive repair adhesive from discarded PET bottles and through the phase inversion technique through the complete precipitation of recycled PET. Said film may be used as an adhesive and may be applied to any painted or unpainted metal surface, without surface preparation, which eliminates the need for steps in the painting process and makes the process disclosed in the present invention less costly. Said repair adhesive is easy to apply, simply by removing the liner and applying it to the structure, without requiring specialized labor, and has a minimum durability of 2 years, and may or may not be removed for maintenance painting. Once removed, the PET adhesive comes off easily in the conventional hydro-jetting process.