Sequentially Polymerized Hybrid Latex for Coatings

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Solution Overview

Problem

Existing polymer latex compositions face challenges in achieving a balance between durability, long open time, good flow and leveling, easy application, and resistance to water sensitivity while being cost-effective, particularly when combining all-acrylic and vinyl acrylic polymers, which often result in compatibility issues.

Innovation Solution

Aqueous crosslinkable core-shell latex composition with an all-acrylic polymer core and a vinyl-acrylic polymer shell, where the shell contains crosslinkable monomers like diacetone acrylamide, diacetone methacrylamide, or acetoacetoxyethyl methacrylate, and a cross-linking agent such as adipic dihydrazide, allowing for sequential polymerization to enhance film properties and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If all-acrylic and vinyl acrylic polymers are blended to achieve long open time and ease of application, then hydrophilicity and application properties are improved, but water sensitivity and durability are compromised

Engineering Contradiction:

Improveease of applicationVSAvoidwater sensitivity

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The polymer is segmented into distinct core and shell phases through sequential emulsion polymerization. The core contains all-acrylic polymer providing durability and water resistance, while the shell contains vinyl acrylic polymer providing hydrophilicity and ease of application. This segmentation allows both polymer types to coexist without compromising overall performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite polymer structure combining all-acrylic and vinyl acrylic polymer phases within single latex particles. This composite approach allows the material to exhibit properties of both constituent polymers simultaneously, achieving long open time and ease of application while maintaining water sensitivity resistance.

Inventive Principle:

Principle #40Composite materials

2Duration of action of moving object

If all-acrylic and vinyl acrylic polymers are blended to achieve long open time, then film formation time is extended, but compatibility issues and performance compromise arise

Engineering Contradiction:

Improveopen timeVSAvoidpolymer compatibility

Core Design Contradiction:

Duration of action of moving objectVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the latex particle have different compositions optimized for specific functions. The core region provides water resistance and durability, while the shell region provides hydrophilicity and extended open time. This local quality differentiation resolves compatibility issues by preventing direct mixing of incompatible polymer types.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If vinyl acetate monomers are used to achieve long open time and ease of application, then application properties are improved, but cost increases due to higher vinyl acetate pricing

Engineering Contradiction:

Improveease of applicationVSAvoidmaterial cost

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The invention optimizes the vinyl acetate content parameter within the shell phase to achieve the desired balance between application properties and cost. By controlling the amount of vinyl acetate monomer (typically 30-70 wt% of shell composition), the formulation achieves long open time and ease of application while limiting the quantity of expensive vinyl acetate used.

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 resulting hybrid polymer exhibits improved durability, block resistance, and reduced water sensitivity, while maintaining cost-effectiveness and ease of application, with enhanced film-forming properties and improved flow and leveling characteristics.

Implementation Method 1

The crosslinkable monomer is selected from the group consisting of diacetone acrylamide, diacetone methacrylamide and acetoacetoxyethyl methacrylate or a combination thereof, and the aqueous latex composition further comprises a cross-linking agent in an aqueous phase to crosslink with the crosslinkable monomer when water evaporates

Methodology Applied

Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

a cross-linking agent in an aqueous phase to crosslink with the crosslinkable monomer when water evaporates

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3167020B1Sequentially polymerized hybrid latex

Publication Date: 2019.05.15 BENJAMIN MOORE & CO

AI summary

The present invention relates to a hybrid latex composition containing polymer particles that are polymerized in at least two stages including a first phase acrylic core polymer, and a second phase vinyl acrylic shell polymer including a monomer that is crosslinkable under ambient conditions. Paint compositions and architectural coatings containing the latex composition according to the invention are also described herein, as well as methods for making the same.