Aqueous Coating Composition for Cement Substrates

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Solution Overview

Problem

Commercially available coatings for cement and fiber cement substrates face issues with adhesion, water resistance, and damage from freezing-thaw cycles, particularly in colder climates, and are often associated with high volatile organic compound (VOC) solvents.

Innovation Solution

A coating composition comprising a multistage latex polymer with a soft and hard stage, along with an epoxy-functional silane coupling agent, is developed to provide excellent adhesion, abrasion resistance, and low VOC characteristics, which is applied to cement and fiber cement substrates to enhance their durability and resistance to freezing-thaw cycles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If higher-Tg polymer systems are used to achieve hard and abrasion resistant coatings, then coating hardness and abrasion resistance are improved, but VOC solvent content increases

Engineering Contradiction:

Improvecoating hardnessVSAvoidVOC solvent content

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the glass transition temperature (Tg) parameter of the polymer from high-Tg to low-Tg, enabling the use of aqueous solvents instead of VOC solvents while maintaining coating performance through the low-Tg polymer formulation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent substitutes VOC solvents with water-based aqueous solvents, replacing the harmful chemical system with a environmentally friendly alternative while achieving the same coalescence and film formation functions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Strength

If higher-Tg polymer systems are used to achieve hard and abrasion resistant coatings, then coating hardness and abrasion resistance are improved, but adhesion to cement substrates deteriorates

Engineering Contradiction:

Improvecoating hardnessVSAvoidadhesion

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the Tg parameter from high to low, which fundamentally alters the polymer's interaction with the substrate, enabling better adhesion through improved wetting and bonding while maintaining hardness through optimized polymer composition

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating system combining low-Tg polymer with specific additives and modifiers to achieve both adhesion to cement substrates and the required hardness, rather than relying on a single high-Tg polymer

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If conventional coatings are used on fiber cement substrates, then initial coating application is simple, but resistance to freezing-thaw cycles deteriorates

Engineering Contradiction:

Improvecoating application simplicityVSAvoidfreeze-thaw resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent modifies the polymer's glass transition temperature and compositional parameters to create a flexible yet durable coating that can withstand the expansion and contraction stresses of freezing-thaw cycles while remaining easy to apply

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent skips the problematic intermediate stage where water absorbs into the substrate and freezes by creating a protective barrier that prevents water penetration, thereby eliminating the freeze-thaw damage mechanism

Inventive Principle:

Principle #21Skipping (Rushing through)

4Productivity

If heavy fiber cement boards are stacked for storage, then storage efficiency is improved, but coating surface is damaged by crushing

Engineering Contradiction:

Improvestorage efficiencyVSAvoidcoating surface integrity

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The patent applies a protective coating before storage that acts as a cushioning layer, absorbing and distributing the crushing forces from stacked boards to prevent damage to the underlying substrate and maintain coating integrity

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 coating composition achieves improved adhesion, abrasion resistance, and resistance to freezing-thaw cycles while minimizing VOC emissions, effectively addressing the challenges faced by existing coatings and enhancing the durability of cement and fiber cement substrates.

Implementation Method 1

an epoxy-functional silane-coupling agent... the silane coupling agent reacts with the acetoacetoxy functionality of the latex polymer

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

the silane coupling agent reacts with the acetoacetoxy functionality of the latex polymer

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Data Source

PatentEP2035516B2High performance aqueous coating compositions

Publication Date: 2017.01.04 VALSPAR SOURCING INC

AI summary

This invention relates to coating compositions that include water; a latex polymer and a silane coupling agent. The latex polymer preferably comprises acetoacetoxy functionality, or is a multistage latex, or is an acetoacetoxy functional multistage latex. The silane coupling agent is preferably a functionalized silane coupling agent (more preferably an epoxy-functional silane coupling agent). The compositions may be used to coat a variety of substrates, including wood, cement and fiber cement. Articles having the coating applied thereto are also provided.