Aliphatic Polycarbonate Coating Resolving Hydrolytic Stability

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Solution Overview

Problem

Thermosetting acrylic coatings lack flexibility and chemical resistance, while thermosetting polyesters are not hydrolytically stable, making them unsuitable for applications requiring these properties, especially in environments with high humidity or water exposure.

Innovation Solution

A thermosetting coating composition comprising aliphatic polycarbonate resin derived from hydroxyl-containing compounds like 2,2,4,4-tetramethyl-1,3-cyclobutanediol and 1,4-cyclohexane dimethanol, combined with a crosslinker, which provides exceptional toughness, hardness, flexibility, and improved hydrolytic stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermosetting polyesters are used to improve flexibility and chemical resistance, then these properties are enhanced, but hydrolytic stability deteriorates due to susceptible ester linkages

Engineering Contradiction:

Improveflexibility and chemical resistanceVSAvoidhydrolytic stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameter of the polymer backbone from ester linkages to carbonate linkages. This parameter change fundamentally alters the chemical stability profile while maintaining the desired flexibility and chemical resistance properties, directly resolving the hydrolytic stability issue inherent in polyester systems

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite molecular structure combining cyclobutane rings and cyclohexane rings within the polycarbonate backbone. This composite structure provides both the flexibility needed for automotive applications and the enhanced hydrolytic stability required for durability, achieving both properties simultaneously

Inventive Principle:

Principle #40Composite materials

2Stability of the object's composition

If thermosetting acrylics are used to achieve excellent light stability and hydrolysis resistance, then these properties are improved, but flexibility and chemical resistance worsen

Engineering Contradiction:

Improvelight stability and hydrolysis resistanceVSAvoidflexibility and chemical resistance

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent changes the polymer backbone chemistry from acrylic to aliphatic polycarbonate, fundamentally altering the material properties. This parameter change enables simultaneous achievement of hydrolytic stability (inherited from acrylics) and flexibility/chemical resistance (characteristic of polyesters), resolving the contradiction between these property sets

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP2603566B1Thermosetting coating composition

Publication Date: 2017.02.15 EASTMAN CHEM CO

AI summary

The invention is a thermosetting coating composition comprised of an aliphatic polycarbonate resin and a cross linker. The aliphatic polycarbonate resins are derived from hydroxyl containing compounds including 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD) and 1,4- cyclohexane dimethanol (CHDM). The coatings made of these polycarbonates exhibit exceptional toughness; they possess a high degree of hardness while maintaining a high level of flexibility/impact resistance. These polycarbonate resins also exhibited better hydrolytic stability as compared to their polyester counterparts.