Polycarbonate diol and polyurethane using same

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Solution Overview

Problem

Conventional polycarbonate diols used in polyurethane production exhibit inadequate low-temperature characteristics, chemical resistance, and heat resistance, limiting their applications due to high crystallinity and poor flexibility.

Innovation Solution

A polycarbonate diol is developed with a specific structural composition, comprising a structural unit from a compound with a divalent alkylene group of 3 to 5 carbon atoms and another from a compound with 8 to 20 carbon atoms, achieving a balanced hydroxyl value of 20 to 450 mg-KOH/g and a glass transition temperature of -30° C. or less, enhancing chemical resistance, flexibility, and heat resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polycarbonate diol synthesized from 1,6-hexanediol is used, then heat resistance and hydrolysis resistance are improved, but low-temperature characteristics such as flexibility and elongation deteriorate due to high crystallinity

Engineering Contradiction:

Improveheat resistance and hydrolysis resistanceVSAvoidlow-temperature characteristics

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies composite materials by copolymerizing 1,6-hexanediol with other dihydroxy compounds (such as 1,4-butanediol, 1,5-pentanediol, or dihydroxy compounds with substituents) to create a polycarbonate diol that combines the heat resistance and hydrolysis resistance of 1,6-hexanediol-derived units with the low crystallinity and improved low-temperature characteristics of the co-monomer units

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by introducing dihydroxy compounds with specific local structural features (such as substituents on the main chain or specific carbon numbers) to local regions of the polymer chain, creating segments with different crystallinity and flexibility characteristics that collectively improve overall low-temperature performance while maintaining thermal stability

Inventive Principle:

Principle #3Local quality

2Temperature

If polycarbonate diol with high crystallinity is used, then heat resistance is improved, but chemical resistance and texture quality deteriorate

Engineering Contradiction:

Improveheat resistanceVSAvoidchemical resistance

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The patent uses composite materials by combining 1,6-hexanediol units (which provide heat resistance) with other dihydroxy compound units (which improve chemical resistance and reduce excessive crystallinity), creating a balanced copolymer structure that achieves both heat resistance and chemical resistance simultaneously

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS11220572B2Polycarbonate diol and polyurethane using same

Publication Date: 2022.01.11 MITSUBISHI CHEM CORP

AI summary

The present invention relates to a polycarbonate diol comprising a structural unit derived from a compound represented by the following formula (A) and a structural unit derived from a compound represented by the following formula (B), wherein the hydroxyl value is from 20 to 450 mg-KOH/g:HO—R1—OH (A)HO—R2—OH (B)the glass transition temperature of said polycarbonate diol as measured by a differential operating calorimeter is −30° C. or less and the average carbon number of a dihydroxy compound obtained by hydrolyzing said polycarbonate diol is from 3 to 5.5.