Non-toxic Polyimide Solutions Using DMSO Solvent Mixtures

Solution Overview

Problem

Existing polyimide solutions face challenges with toxic and ecologically harmful solvents, poor storage stability, high melting points, and limited application in coating applications due to the use of CMR and SVHC classified substances like NMP, DMAc, and DMF, which restrict their use and safety requirements.

Innovation Solution

A solvent mixture comprising dimethylsulfoxide (DMSO) with co-solvents such as primary, secondary, and tertiary alkanolamines, benzyl alcohol, cyclohexanone, xylene, acetophenone, and propylene glycol, which eliminates the need for CMR and SVHC substances, providing improved storage stability, low melting points, and high solubility for aromatic polyimides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional solvents like NMP, DMAc, or DMF are used for polyimide solutions, then good solubility and commercial availability are achieved, but ecological and toxicological harm increases due to CMR and SVHC classification

Engineering Contradiction:

ImprovesolubilityVSAvoidecological and toxicological harm

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful CMR and SVHC solvents (NMP, DMAc, DMF) from the polyimide solution system, replacing them with environmentally benign alternatives like water, alcohols, or carboxylic acids that maintain solubility without the toxicological and ecological harms of conventional solvents

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces intermediary substances such as salts (e.g., lithium chloride, calcium chloride) or surfactants that act as mediators to enable polyimide solubility in environmentally friendly solvents like water or alcohols, which would otherwise be incapable of dissolving the polyimide on their own

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If DMSO is used as a solvent for polyimide solutions, then ecological and toxicological problems are reduced, but storage stability deteriorates due to phase inversion from water absorption

Engineering Contradiction:

Improveecological and toxicological harmVSAvoidstorage stability

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent creates composite solvent systems combining DMSO with other solvents like alcohols, carboxylic acids, or water-miscible solvents to form a mixed solvent system that maintains both the ecological benefits of reduced toxicity and the storage stability needed to prevent phase inversion and water absorption issues

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the solvent composition parameters by adjusting the ratios and types of solvents in the mixture to optimize both storage stability and ecological performance, selecting specific combinations that resist phase inversion while maintaining low toxicity

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If DMSO is used as a solvent for polyimide solutions, then ecological problems are reduced, but melting temperature increases leading to freezing during transport

Engineering Contradiction:

Improveecological harmVSAvoidmelting temperature

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

The patent develops composite solvent systems that combine DMSO with lower freezing point solvents such as alcohols or water-miscible solvents, creating a mixed system that maintains the ecological benefits of DMSO while reducing the overall freezing point to prevent transport-related freezing

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent adjusts the temperature-related parameters of the solvent system by selecting solvents with appropriate freezing points and optimizing their combinations to ensure the polyimide solution remains liquid across the expected transport temperature range while maintaining ecological performance

Inventive Principle:

Principle #35Parameter changes

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 solvent mixture enables the production of polyimide solutions with enhanced storage stability, low viscosity, and broad temperature compatibility, allowing for safe and efficient use in various applications, including coating, while minimizing safety and administrative requirements.

Implementation Method 1

A solvent mixture comprising dimethylsulfoxide (DMSO) with co-solvents such as primary, secondary, and tertiary alkanolamines, benzyl alcohol, cyclohexanone, xylene, acetophenone, and propylene glycol, which eliminates the need for CMR and SVHC substances, providing improved storage stability, low melting points, and high solubility for aromatic polyimides.

Methodology Applied

Scientific EffectSolvation: Solvation

Implementation Method 2

The solvent mixture enables the production of polyimide solutions with enhanced storage stability, low viscosity, and broad temperature compatibility, allowing for safe and efficient use in various applications, including coating, while minimizing safety and administrative requirements.

Methodology Applied

Scientific EffectFreezing point depression: Freezing

Data Source

PatentUS20220403170A1Non-toxic polyimide solutions

Publication Date: 2022.12.22 EVONIK FIBERS

AI summary

The invention relates to new polyimide solutions having ecological and toxicological benefits compared to existing polyimide solutions as well as well as b their use, in particular for coating applications.