Chemical Stripping Sealant for Aircraft Composite Surfaces

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Solution Overview

Problem

Current depaint processes for aircraft are costly and inefficient, particularly due to the need for masking with aluminum-backed tape and concerns about chemical strippers damaging composite surfaces, which requires additional protective coatings and increases process complexity.

Innovation Solution

A method involving the application of a low adhesion sealant to fill ingression points on the surface, allowing a chemical stripping agent to remove coatings while preventing ingress into sensitive areas, and optionally using a surfacer layer as a barrier to protect the composite surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If masking tape is used to cover aircraft seams during chemical stripping, then chemical stripper ingression into the aircraft is prevented, but cost increases and paint stripping in areas proximate to seams is prevented

Engineering Contradiction:

Improveprevention of chemical stripper ingressionVSAvoidcost and process efficiency

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent removes the masking tape step entirely from the process. Instead of applying tape to seams and then stripping paint around it, the process applies chemical stripper directly to the entire surface including seams, eliminating the need for masking and enabling paint removal at seam locations.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the conventional approach by not preventing stripper contact with seams through masking, but rather allowing it and then removing any residue afterward. The sequence is reversed: apply stripper to all surfaces including seams, then clean residual stripper from seams, rather than masking seams first and restricting stripper application.

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If chemical stripping agent is applied to composite surfaces, then paint removal is achieved, but damage to the composite resin matrix may occur

Engineering Contradiction:

Improvepaint removal efficiencyVSAvoiddamage to composite resin matrix

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a barrier coating as an intermediary layer between the chemical stripper and the composite surface. This barrier coating is specifically selected to be resistant to the chemical stripper, allowing the stripper to remove paint while the barrier coating protects the underlying composite resin matrix from damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical resistance parameters by selecting a barrier coating with specific chemical properties that resist the stripper. The barrier coating's chemical composition is chosen to withstand the stripper's action, creating a protective interface that allows aggressive paint removal without composite damage.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If a barrier coating is applied to protect composite surfaces during stripping, then composite damage is prevented, but process complexity and cost increase

Engineering Contradiction:

Improveprotection of composite surfaceVSAvoidnumber of coatings and process steps

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the barrier coating multi-functional by selecting a coating that simultaneously serves as both the protective barrier during stripping and as part of the final aircraft surface system. The barrier coating is chosen from aircraft coating systems that will ultimately be applied to the aircraft, eliminating the need for separate temporary protective coatings and reducing overall process complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This method reduces costs by eliminating the need for masking tape and separate barrier coatings, effectively removes coatings up to seams, and provides protection for composite surfaces from UV damage and corrosion.

Implementation Method 1

applying a sealant to at least a portion of a surface of an object, the surface comprising a coating and one or more ingression points, the sealant filling the one or more ingression points

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

applying a stripping agent to the sealed surface to remove at least a portion of the coating to form a stripped surface

Methodology Applied

Scientific EffectChemical dissolution: Solvation

Data Source

PatentUS11952512B2Chemical process for stripping surfaces

Publication Date: 2024.04.09 THE BOEING CO

AI summary

A method of chemically stripping a surface is described. The method comprises applying a sealant to at least a portion of a surface of an object, the surface comprising a coating and one or more ingression points, the sealant filling the one or more ingression points to form a sealed surface. The method further comprises applying a stripping agent to the sealed surface to remove at least a portion of the coating to form a stripped surface.