Transparent Polyimide-Polyester Blend Phase Separation

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Solution Overview

Problem

Achieving transparency in polyimide-polyester compositions with higher levels of polyesters is challenging due to phase separation, which leads to haze and opacity, while maintaining good melt flow, tensile, and flexural properties, especially when exposed to heat and humidity.

Innovation Solution

A thermoplastic polymer composition comprising a bisphenol A-free blend of polyetherimides, polyethylene terephthalate with specific diethylene glycol content and intrinsic viscosity, and low levels of stabilizers, antimony, cobalt, and titanium, which maintains transparency and physical properties even at higher polyethylene terephthalate levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If higher levels of polyethylene terephthalate are used in polyimide-polyester compositions, then the transparency is improved, but phase separation occurs leading to haze and opacity

Engineering Contradiction:

ImprovetransparencyVSAvoidphase separation

Core Design Contradiction:

Illumination intensityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by precisely controlling the intrinsic viscosity of polyethylene terephthalate (0.70-1.30 dl/g) and the molecular weight of polyimide (5,000-80,000 Daltons), along with specific compositional ratios (40-60 pbw each), to achieve a homogeneous mixture that prevents phase separation while maintaining high transparency and desired mechanical properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining polyimide and polyethylene terephthalate in specific proportions (40-60 pbw each) with controlled molecular characteristics, forming a transparent composition that leverages the complementary properties of both polymers while preventing adverse phase separation effects

Inventive Principle:

Principle #40Composite materials

2Illumination intensity

If higher levels of polyethylene terephthalate are used to improve transparency, then the haze and opacity increase due to phase separation

Engineering Contradiction:

ImprovetransparencyVSAvoidhaze and opacity

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent controls the intrinsic viscosity of polyethylene terephthalate within 0.70-1.30 dl/g and maintains specific compositional ratios to prevent phase separation, thereby achieving high transparency while minimizing haze and opacity in the final molded articles

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If transparent polyimide-polyester compositions are achieved, then the melt flow properties, tensile properties, and flexural properties may be compromised

Engineering Contradiction:

ImprovetransparencyVSAvoidmelt flow, tensile, and flexural properties

Core Design Contradiction:

Illumination intensityVSStrength

Solution Approach 1:

The patent optimizes multiple parameters simultaneously: polyimide molecular weight (5,000-80,000 Daltons), polyethylene terephthalate intrinsic viscosity (0.70-1.30 dl/g), and compositional ratios (40-60 pbw each), to achieve a balance where transparency is maintained while melt flow rate, tensile strength, and flexural properties meet performance requirements

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent designs a composite material system where polyimide and polyethylene terephthalate are combined in optimized proportions with controlled molecular characteristics, creating a synergistic effect that maintains both optical clarity and mechanical performance including melt flow, tensile, and flexural properties

Inventive Principle:

Principle #40Composite materials

4Illumination intensity

If transparent polyimide-polyester compositions are achieved, then the properties may deteriorate after exposure to heat and humidity

Engineering Contradiction:

ImprovetransparencyVSAvoidproperty retention after heat and humidity exposure

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The patent controls the molecular weight of polyimide (5,000-80,000 Daltons) and the intrinsic viscosity of polyethylene terephthalate (0.70-1.30 dl/g), along with specific compositional ratios, to create a composition that maintains transparency while exhibiting improved thermal and humid stability, thereby retaining mechanical and optical properties after environmental exposure

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8546516B2Transparent polyimide-polyester compositions, method of manufacture, and articles thereof

Publication Date: 2013.10.01 SHPP GLOBAL TECH BV

AI summary

A thermoplastic polymer composition comprises a combination of: 40 to 60 pbw, of a polyetherimides, polyetherimide sulfones, or combination thereof having a weight average molecular weight from 5,000 to 80,000 Daltons; 40 to 60 pbw of a polyethylene terephthalate, the polyethylene terephthalate having a diethylene glycol content from 0.1 to 4 wt %, based on the weight of the polyethylene terephthalate, an intrinsic viscosity that is more than 0 and less than 0.83 dl/g, and carboxylic acid end groups in an amount from 10 to 150 meq/Kg; from 0 pbw to 1 pbw, based on 100 pbw of the polymer composition of a stabilizer selected from phenol-containing stabilizers, phosphorus-containing stabilizers, or a combination thereof; and, based on the weight of the polyethylene terephthalate, 10 to 300 antimony; 0 to 300 ppm of cobalt; and 0 to 300 ppm of titanium; wherein the polymer composition is bisphenol A free.