Water-Based Paints with High MW Acrylic for Smoothness

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Solution Overview

Problem

Conventional water-based paints exhibit inferior coating film performance in terms of mechanical properties and water resistance compared to solvent-based paints, and high molecular weight acrylic resins used to improve performance often degrade the appearance and workability of the coating.

Innovation Solution

A water-based paint composition comprising water-dispersible acrylic polymer particles with a weight-average molecular weight of at least 1,100,000 and low absorbance, which ensures uniform distribution and high transparency, combined with a reactive group-containing resin and optionally a curing agent, to achieve superior surface smoothness and water resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high molecular weight acrylic resin is used to improve coating film performance and water resistance, then mechanical properties and water resistance are improved, but coated surface smoothness and coating workability are degraded

Engineering Contradiction:
Improvewater resistanceVSAvoidcoated surface smoothness
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling the weight-average molecular weight to be at least 1,100,000 and the absorbance at 330 nm to be not higher than 0.2 when measured at a mass concentration of 1.35% in 1,4-dioxane solvent. These specific parameter thresholds enable the polymer to achieve both high water resistance and excellent surface smoothness, resolving the contradiction between performance improvement and appearance quality.

Inventive Principle:
Principle #35Parameter changes

2Strength

If high molecular weight acrylic resin is used to improve coating film performance, then mechanical properties are improved, but coating workability is degraded

Engineering Contradiction:
Improvemechanical propertiesVSAvoidcoating workability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The patent resolves this contradiction through parameter changes by establishing specific thresholds for weight-average molecular weight (at least 1,100,000) and absorbance (not higher than 0.2 at 330 nm). These controlled parameters enable the resin to provide enhanced mechanical strength while maintaining good coating workability, as the low absorbance indicates high transparency and uniform dispersion in the coating formulation.

Inventive Principle:
Principle #35Parameter changes

3Object-generated harmful factors

If conventional water-based paint is used to reduce VOC discharge, then environmental performance is improved, but coating film performance is inferior to solvent-based paint

Engineering Contradiction:
ImproveVOC dischargeVSAvoidcoating film performance
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The patent resolves this contradiction by introducing a water-dispersible acrylic polymer with specifically controlled parameters: weight-average molecular weight of at least 1,100,000 and absorbance not higher than 0.2 at 330 nm. These parameter changes enable conventional water-based paints to achieve coating film performance comparable to or exceeding solvent-based paints, while maintaining the environmental advantage of reduced VOC discharge.

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 composition forms a coating film with excellent surface smoothness and water resistance, addressing the limitations of conventional water-based paints while maintaining good flow properties and appearance.

Implementation Method 1

water-dispersible acrylic polymer particles having a weight-average molecular weight of at least 1,100,000 and an absorbance not higher than 0.2 at the wavelength of 330 nm as measured with spectrophotometer in the state of a liquid dispersion at a mass concentration of 1.35% in 1,4-dioxane solvent

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS8283405B2Water-based paint compositions
Publication Date: 2012.10.09 KANSAI PAINT CO LTD

AI summary

This invention provides water-based paint compositions which can form coating film excelling in finished appearance such as coated surface smoothness and also of excellent performance in such properties as water resistance, which comprise water-dispersible acrylic polymer particles (A), reactive group-containing resin (B) and optionally curing agent (C), the water-dispersible acrylic polymer particles (A) having a weight-average molecular weight of at least 1,100,000 and an absorbance not higher than 0.2 at the wavelength of 330 nm as measured with spectrophotometer in the state of a liquid dispersion at a mass concentration of 1.35% in 1,4-dioxane solvent.