Elastomeric Acrylate Latex for Masonry Coatings
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Solution Overview
Problem
Existing masonry coatings face challenges with cracking due to expansion and contraction of underlying substrates, leading to water-conducting channels, alkaline pH-induced efflorescence, and high dirt pick-up, while requiring improved water resistance, alkaline resistance, and UV stability.
Innovation Solution
A single polymer elastomeric coating composed of C8-C12 alkyl acrylate monomers and/or vinyl esters of C10-C12 versatic acids, with 5-15 wt% acrylonitrile, and optional UV-activated photosensitive species and silane adhesion promoters, providing long-term elasticity, low dirt pick-up, and resistance to alkalinity and UV exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If masonry coatings have enough elasticity to cover cracks in underlying masonry substrates, then they can bridge expansion and contraction cracks, but they often suffer from tacky surfaces that allow dirt and grime to adhere and bind itself into the coating resulting in high dirt pick up
Solution Approach 1:
The patent modifies the chemical composition parameters of the coating by incorporating specific polymers (acrylic, vinyl acrylic, styrene acrylic copolymers) with controlled glass transition temperatures and molecular weights. It also adjusts the crosslinking density and uses silane-modified polymers to achieve the optimal balance between elasticity and surface properties that resist dirt adhesion.
Solution Approach 2:
The patent creates a composite coating system combining multiple polymer types (acrylic, vinyl acrylic, styrene acrylic) with silane crosslinkers and various additives. This composite approach allows the coating to simultaneously achieve crack-bridging elasticity through the polymer matrix while the crosslinked network and surface modifiers prevent dirt adhesion.
2Reliability
If water-resistant layers are formed using asphaltic or bituminous materials, then water resistance is improved, but the layers are prone to cracking as the underlying architectural components expand, contract or crack providing water-conducting channels
Solution Approach 1:
The patent transitions from rigid asphaltic materials to flexible polymer-based coatings by selecting copolymers with specific glass transition temperatures below ambient service conditions. This parameter change in material flexibility allows the coating to accommodate substrate movement while maintaining water resistance.
Solution Approach 2:
The patent employs a flexible polymer coating film that can deform with the underlying masonry substrate. The elastic nature of the acrylic and vinyl acrylic copolymers creates a flexible protective layer that bridges cracks rather than cracking itself, preventing water infiltration pathways.
3Object-generated harmful factors
If masonry substrates impart alkaline pH to moisture or water that directly interacts with the masonry, then efflorescence effect occurs where soluble salts deposit on the structure or coating, but the coating needs to resist alkaline pH to withstand contact with alkaline water
Solution Approach 1:
The patent incorporates sacrificial alkalinity-resistant components such as silane crosslinkers and specific polymer formulations that can neutralize or resist alkaline attack. These components provide temporary chemical buffering capacity to protect the coating system from efflorescence-causing alkaline environments.
Solution Approach 2:
The patent uses silane-modified polymers and copolymer structures as intermediary layers between the alkaline masonry substrate and the coating matrix. These intermediaries resist alkaline hydrolysis and prevent the migration of soluble salts that cause efflorescence, while maintaining coating integrity.
4Ease of operation
If existing masonry coatings are used, then they provide basic water-repellant barrier properties, but they suffer from cracking, efflorescence, and high dirt pick up that compromise their long-term performance
Solution Approach 1:
The patent formulates a multi-component composite coating system combining acrylic copolymers, vinyl acrylic copolymers, silane crosslinkers, and functional additives. This composite structure integrates crack-bridging elasticity, water repellency, efflorescence resistance, and dirt pickup resistance into a single coordinated system.
Solution Approach 2:
The patent optimizes multiple parameters simultaneously: polymer molecular weight and composition for elasticity, crosslinking density for durability, surface energy modifiers for dirt resistance, and alkalinity buffers for efflorescence prevention. This multi-parameter optimization achieves comprehensive performance improvement.
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 effectively bridges cracks in masonry substrates, resists efflorescence, and maintains a tack-free surface with low dirt pick-up, while ensuring durability and appearance, addressing the limitations of commodity and specialty acrylate polymers.
Implementation Method 1
The coating composition may contain a UV activated photosensitive species
Data Source
AI summary
Acrylate latexes are described which provide properties of good balance of moderate elongation, low dirt pick up, alkaline resistance, UV light resistance, and efflorescence resistance for masonry coatings. These latexes have a large portion of repeating units from C8-C12 alcohol esters of acrylic acid and/or vinyl versatates along with 5-15 weight percent of repeating units from acrylonitrile. They have a glass transition temperature of −50 to +10° C.