Hydrophobic Low Density Additives for Composite Moisture Control

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Solution Overview

Problem

Composite materials face challenges with moisture absorption and expansion, leading to degradation due to their porous structure, which allows water ingress and causes dimensional changes, especially in exterior applications exposed to humidity and freeze-thaw cycles.

Innovation Solution

Engineered low density additives with a porous structure are treated to become hydrophobic and reactive, reducing moisture movement and enhancing bonding within the composite matrix, thereby maintaining strength and reducing moisture expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If porous additives are used to reduce density, then the overall density of the composite material is reduced, but water and moisture absorption and movement increase

Engineering Contradiction:
ImprovedensityVSAvoidmoisture absorption
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the surface energy characteristics of the porous additive particles through chemical treatment. Specifically, silane coupling agents or other surface treatments are used to transform the surface from hydrophilic to hydrophobic, thereby changing the interaction between the porous structure and moisture while maintaining the low density property

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite surface structure on the porous particles by combining the base porous material (such as expanded perlite, pumice, or volcanic ash) with surface-active compounds like silanes. This composite surface structure provides both the low density benefit of porosity and the moisture resistance of hydrophobic surface chemistry

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If porous structure is used for low density, then density is reduced, but bonding strength may be compromised due to moisture ingress

Engineering Contradiction:
ImprovedensityVSAvoidbonding strength
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The surface treatment modifies the chemical parameters of the particle surface, creating reactive silane groups that can form strong chemical bonds with the composite matrix. This prevents moisture-induced bond degradation while preserving the porous low-density structure

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The surface-treated porous particles act as intermediaries between the composite matrix and the internal porous structure. The hydrophobic surface layer mediates by repelling moisture away from the porous interior while providing bonding interfaces with the surrounding matrix, thus protecting the internal structure from moisture damage

Inventive Principle:
Principle #24Intermediary (Mediator)

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 treated additives effectively reduce moisture absorption and expansion in composite materials, improving their durability and performance in varying moisture conditions while maintaining strength and accelerating formation time.

Implementation Method 1

contacting the particles with a chemical to reduce its surface energy, rendering the particle surface hydrophobic

Methodology Applied
Scientific EffectSurface energy reduction: Surfactant

Implementation Method 2

particles having a porous structure with hydroxyl groups deposited on its surface to provide hydrophilic and reactive sites on the surface

Methodology Applied
Scientific EffectHydroxyl group deposition: Deposition (physical)

Data Source

PatentEP2142486B1A method of making a low density additive
Publication Date: 2018.05.30 JAMES HARDIE TECH LTD
  • EP2142486B1 patent drawingFigure 1~2
  • EP2142486B1 patent drawingFigure 3~4
  • EP2142486B1 patent drawingFigure 5~6

AI summary

Low density additives and methods of making said additives for composite materials are provided. The low density additives have at least a partial or complete water repellant property that reduces moisture migration, absorption, and retention within a composite material in which it is incorporated into. Active sites are engineered onto the surface of the low density additives to enhance bonding of the additives within a composite matrix. Reduced water movement and enhanced bonding lead to an increased strength and durability performance for a composite material comprising such additives. Composite materials incorporating one or more engineered low density additives as also provided, such composite materials having enhanced strength and durability. Such composite materials may be made from a Hatschek process. The composite materials may be further used as interior and exterior building products.