Cyclobutanediol Polyester Compositions for Amorphous Article Processing

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Solution Overview

Problem

Current polyester compositions based on terephthalic acid and cyclohexanedimethanol exhibit limitations in impact strength, glass transition temperature, and processability, leading to difficulties in forming amorphous articles and requiring additional modifiers that compromise properties like ductile-to-brittle transition temperatures and chemical resistance.

Innovation Solution

A polyester composition comprising terephthalic acid, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and cyclohexanedimethanol with specific thermal stabilizers, such as alkyl phosphate esters, which enhances impact strength, hydrolytic stability, chemical resistance, and processability, allowing for easier production without issues like bubbling and erratic melt levels, and enables large-scale commercial production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If PCT crystallizes rapidly upon cooling from the melt to maintain structural integrity, then crystallization speed is improved, but it becomes very difficult to form amorphous articles by extrusion, injection molding, and other forming methods

Engineering Contradiction:

Improvecrystallization speedVSAvoidformability of amorphous articles

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent modifies the crystallization behavior by changing chemical parameters - introducing copolymer units (isophthalate, ethylene glycol) that alter the molecular structure and slow down crystallization kinetics, enabling amorphous article formation while maintaining service temperature performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite polyester system combining PCT with copolymer units (isophthalate-ethylene glycol sequences) that provide both slow crystallization for amorphous forming and high service temperature, achieving properties that neither component alone could provide

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If sufficient ethylene glycol residues or isophthalic acid modifiers are included in copolyester formulations to provide long crystallization half-times for amorphous products, then crystallization control is improved, but glass transition temperature and impact strength deteriorate

Engineering Contradiction:

Improvecrystallization half-timeVSAvoidimpact strength

Core Design Contradiction:

Duration of action of stationary objectVSStrength

Solution Approach 1:

The patent optimizes the composition parameters by limiting ethylene glycol residues to 0.1-10 mol% and isophthalate units to 1-30 mol%, finding a balance that provides sufficient crystallization control while maintaining impact strength and glass transition temperature above critical thresholds

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates localized structural features - isolated ethylene glycol/isophthalate sequences distributed within the PCT matrix - that provide crystallization control without creating extensive low-Tg regions that would compromise overall impact strength

Inventive Principle:

Principle #3Local quality

3Strength

If cyclobutanediol is incorporated into polyester compositions to improve impact strength and toughness, then mechanical properties are improved, but inherent viscosity and melt viscosity increase making processing difficult

Engineering Contradiction:

Improveimpact strengthVSAvoidprocessability

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent controls the cyclobutanediol content at 10-90 mol% of total glycol and limits inherent viscosity to 0.35-1.2 dL/g, optimizing the balance between impact strength enhancement and processability for standard manufacturing equipment

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8299204B2Polyester compositions which comprise cyclobutanediol and certain thermal stabilizers, and/or reaction products thereof

Publication Date: 2012.10.30 EASTMAN CHEM CO

AI summary

Described as one aspect of the invention are polyester compositions containing: (I) at least one polyester which comprises: (a) dicarboxylic acid component comprising: (i) 70 to 100 mole % of terephthalic acid residues; (ii) 0 to 30 mole % of aromatic dicarboxylic acid residues having up to 20 carbons atoms; and (iii) 0 to 10 mole % of aliphatic dicarboxylic acid residues having up to 16 carbon atoms; and (b) a glycol component comprising: (i) 1 to 99 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and (ii) 1 to 99 mole % of cyclohexanedimethanol residues; and (II) at least one thermal stabilizer chosen from at least one alkyl phosphate esters, aryl phosphate esters, mixed alkyl aryl phosphate esters, reaction products thereof, and mixtures thereof; wherein the total mole % of the dicarboxylic acid component is 100 mole %, and wherein the total mole % of the glycol component is 100 mole %.