Polypropylene Aqueous Coating Composition for Corrosion-Resistant Cans

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Solution Overview

Problem

Existing aqueous coating compositions for cans lack corrosion resistance, processability, and coating workability, and often contain legally regulated substances like bisphenol A, limiting material selection and performance.

Innovation Solution

An aqueous coating composition comprising a polyolefin resin aqueous dispersion with polypropylene, a crosslinking agent reacting with a carboxyl group, amino silane, and an organic solvent with specific water solubility and boiling point ranges, enhancing corrosion resistance, processability, and coating workability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a polyolefin resin is used as a base resin to avoid regulated substances like BPA, then the coating composition becomes free from legally regulated substances, but corrosion resistance and processability of the coating film become insufficient

Engineering Contradiction:
Improvepresence of regulated substancesVSAvoidcorrosion resistance
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent uses a composite resin system combining polyolefin resin with polyester resin and/or polyamide resin. This composite approach maintains freedom from regulated substances like BPA while achieving sufficient corrosion resistance and processability that pure polyolefin cannot provide alone.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the base resin by specifying particular types of polyolefin resins (polypropylene, polyethylene, poly-1-butene) and combining them with other resins in specific ratios, thereby changing the functional properties to achieve both regulatory compliance and performance requirements.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If a polyolefin resin is used as a base resin to avoid regulated substances like BPA, then the coating composition becomes free from legally regulated substances, but processability of the coating film becomes insufficient

Engineering Contradiction:
Improvepresence of regulated substancesVSAvoidprocessability
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent combines polyolefin resin with polyester resin and/or polyamide resin to create a composite coating system that maintains freedom from regulated substances while achieving adequate processability that pure polyolefin cannot provide.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent adjusts the chemical composition parameters by selecting specific polyolefin types and combining them with other resins in controlled ratios, thereby improving processability while maintaining regulatory compliance.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If an acrylic modified epoxy resin is used as a base resin to reduce organic solvent use, then the coating composition becomes more environmentally friendly, but storage stability becomes insufficient

Engineering Contradiction:
Improveorganic solvent useVSAvoidstorage stability
Core Design Contradiction:
Loss of energyVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters by specifying particular types and ratios of polyolefin resins, polyester resins, and polyamide resins, thereby achieving adequate storage stability while maintaining low organic solvent content.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite resin system that combines multiple resin types, where the synergistic interaction between components provides sufficient storage stability without requiring high levels of organic solvents.

Inventive Principle:
Principle #40Composite materials

4Object-affected harmful factors

If the number of regulated substances increases, then the environmental and safety standards are improved, but the degree of freedom for selecting raw materials is limited

Engineering Contradiction:
Improveregulated substancesVSAvoidraw material selection freedom
Core Design Contradiction:
Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent develops a universal coating composition formula based on polyolefin resin that can serve multiple functions (corrosion protection, processability, regulatory compliance) and can be adapted to different applications while maintaining freedom from regulated substances.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates a versatile composite resin system that can be adjusted through component ratios to meet different performance requirements while consistently avoiding regulated substances, thereby maintaining raw material selection freedom within the composite framework.

Inventive Principle:
Principle #40Composite materials

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 achieves a coating film with excellent corrosion resistance, processability, and workability, free from regulated substances, suitable for cans.

Implementation Method 1

a crosslinking agent (B) having a functional group that reacts with a carboxyl group

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

an amino silane (C)

Methodology Applied
Scientific EffectSilane chemistry: Chemical Bonding

Implementation Method 3

an organic solvent (D) having water solubility in a range of 0.01 to 5.0 g/100 g and a boiling point in a range of 120 to 250° C.

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS12421413B2Aqueous coating composition
Publication Date: 2025.09.23 KANSAI PAINT CO LTD

AI summary

An aqueous coating composition including: an aqueous dispersion (A) of a polyolefin resin that includes a polypropylene (A1); a crosslinking agent (B) that has a carboxyl group-reactive functional group; an aminosilane (C); and an organic solvent (D) with a water solubility of 0.01-5.0 g/100 g and a boiling point of 120-250° C.