Composite Fiber Cement Subsurface Interfacial Zone

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Solution Overview

Problem

Fiber-reinforced cement (FRC) products face challenges with maintaining adhesion and integrity in extreme environments due to cyclic exposure and mishandling, leading to physical and chemical degradation, and existing surface coatings are not effective in providing long-term durability and resistance to wear, water, and freeze/thaw conditions.

Innovation Solution

A composite building article with a subsurface interfacial zone formed of an interlocking matrix of fiber cement and radiation curable material, which is integrally formed with the substrate and exterior surface, enhancing durability and adhesion, and comprising radiation curable materials like epoxies, urethanes, and acrylates that are primarily cured by radiation, such as electron beam radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional surface coatings are applied to FRC products, then decorative appearance is provided, but adhesion is lost over time due to cyclic exposure and extreme climates

Engineering Contradiction:

Improvedecorative surface appearanceVSAvoidadhesion durability

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The patent merges the decorative coating layer with the FRC substrate by causing the radiation-curable material to penetrate and interlock with the substrate pores, forming a unified composite structure rather than a separate surface layer, thereby maintaining adhesion under cyclic exposure

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The radiation-curable material is applied to the surface of the FRC substrate before final curing, allowing it to penetrate and form interlocking bonds with the substrate pores in advance, creating a pre-established adhesion mechanism that resists subsequent environmental stress

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple protective treatments are applied to FRC products, then durability against environmental agents is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvedurability against environmental agentsVSAvoidnumber of treatments required

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The radiation-curable material performs multiple functions simultaneously: it provides decorative appearance, ensures strong adhesion through substrate interlocking, and delivers protection against environmental agents like water and UV, eliminating the need for separate protective treatments

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates a composite material system where the radiation-curable material and FRC substrate form an integrated structure with enhanced properties, combining the benefits of both materials while reducing the need for additional protective layers

Inventive Principle:

Principle #40Composite materials

3Strength

If radiation curable material penetrates deeply into fiber cement substrate, then adhesion strength is improved, but material viscosity and processing difficulty increase

Engineering Contradiction:

Improveadhesion strengthVSAvoidmaterial processing ease

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent controls the penetration depth and adhesion strength by adjusting parameters of the radiation-curable material such as viscosity, molecular weight, and functional group composition, allowing optimization of both adhesion performance and ease of application

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 composite building article achieves improved durability, weather resistance, and long-term integrity by forming a mechanically interlocking network that resists environmental agents, maintaining adhesion and reducing the need for multiple treatments, while being cost-effective and resistant to wear and freeze/thaw damage.

Implementation Method 1

the radiation curable material in the subsurface interfacial zone is curable primarily by radiation

Methodology Applied

Scientific EffectRadiation curing: Photopolymerisation

Implementation Method 2

cured by radiation, such as electron beam radiation

Methodology Applied

Scientific EffectElectron beam radiation: Electron Beam

Data Source

PatentUS7754320B2Composite fiber cement article with radiation curable component

Publication Date: 2010.07.13 JAMES HARDIE TECH LTD

AI summary

A composite building article is configured with one or more subsurface interfacial zones provided to improve the durability of the article. Each subsurface interfacial zone is made of a matrix of fiber cement and radiation curable material. The radiation curable material forms an interlocking network with the fiber cement to provide a interfacial zone against ingress of environmental agents that can degrade the article. The number, configuration and distribution of the subsurface interfacial zones can vary dependent on the desired characteristics of the final product. The subsurface interfacial zones also improves the adhesion between exterior coatings and the substrate as the interfacial zones can be integrally formed with the substrate as well as exterior coating layer.