Acrylic Latex Granule Coating for Rub-Off and Stain Resistance

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Solution Overview

Problem

Granule loss due to rub off and tracking is a significant issue in building products, especially at high temperatures, leading to reduced lifespan and aesthetic compromise, and the existing technologies fail to provide adequate protection against discoloration caused by asphalt oils adsorption on granules.

Innovation Solution

The application of an acrylic latex coating to granule surface building products, which includes embedding or adhering granules in a substrate and applying an acrylic latex polymer with a specific structural formula, providing increased rub-off protection, improved tracking resistance, and resistance to staining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If granules are embedded in asphalt substrate, then granule adhesion is achieved, but granule loss occurs due to rub off and tracking at elevated temperatures

Engineering Contradiction:
Improvegranule adhesionVSAvoidgranule loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

A latex coating is applied as an intermediary layer between the granules and the asphalt substrate. This latex layer acts as a mediator that enhances the bonding between granules and asphalt, preventing granule loss due to rub off and tracking while maintaining granule adhesion. The latex coating specifically addresses the problem of granule displacement at elevated temperatures by providing an additional adhesive interface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If asphalt oils are present on the surface, then granules adhere to the substrate, but asphalt oils creep onto granules causing discoloration and staining

Engineering Contradiction:
Improvegranule adhesionVSAvoiddiscoloration and staining
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The latex coating serves as a protective intermediary barrier between the asphalt oils and the granule surfaces. While allowing granules to adhere to the substrate through the latex layer, it prevents the asphalt oils from creeping onto and staining the granules, thus maintaining their aesthetic appearance without compromising adhesion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

A thin film of latex coating is applied over the granule-embedded surface. This flexible thin film acts as a protective shield that prevents asphalt oil migration onto granules while maintaining the structural integrity and adhesion of the granule layer to the substrate.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If building products are used at elevated temperatures, then functional performance is maintained, but tracking and granule loss increase

Engineering Contradiction:
Improvefunctional performanceVSAvoidgranule rub loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The latex coating acts as a temperature-resistant intermediary layer that maintains granule adhesion under elevated temperature conditions. It prevents the asphalt substrate from becoming too soft and allowing granule displacement, thereby reducing tracking and rub loss while preserving functional performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The latex coating modifies the surface properties of the building product, creating a layer with different thermal and mechanical characteristics than the underlying asphalt. This parameter change allows the surface to maintain granule retention at elevated temperatures where the base asphalt would otherwise become too soft.

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 acrylic latex coating significantly reduces granule loss by approximately 90% and improves staining resistance by 59%, enhancing the durability and aesthetic appeal of building materials.

Implementation Method 1

there is a tendency for oils in the asphalt surface to creep onto or be adsorbed on the granules' surfaces

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentUS8394730B2Coating for granulated products to improve granule adhesion, staining, and tracking
Publication Date: 2013.03.12 BMIC LLC

AI summary

A building material product and a method of making building material products, having increased resistance to granule rub off and staining. The building material product comprises a substrate having embedded granules and an acrylic latex coating positioned on the granules, where the polymer of the acrylic latex coating has the repeating structural unit [CH2—C(R1)(R2)], where R1 is hydrogen or C1-C8 alkyl; R2 is hydrogen, cyano or —COOR; and R is a linear or branched hydrocarbon containing 1-22 carbon atoms, with the proviso that R1 and R2 are both not hydrogen. The method includes applying this acrylic latex water based composition to a granule embedded substrate.