Polyurethane Moldings Low-Temperature Flexibility

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Polyester-based polyurethane moldings exhibit limited low-temperature flexibility, becoming hard and rigid below −30°C, which is inadequate for applications in extremely cold environments, and existing solutions either lack flexibility or have high specific gravity and poor insulating properties.

Innovation Solution

A process involving the reaction of organic polyisocyanates with polyester polyol, blowing agent, catalyst, propylene carbonate, and specific compounds like benzyl isooctyl adipate to produce elastomeric polyurethane foams with improved low-temperature flexibility and mechanical properties, suitable for use in cold conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If polyester-based polyurethane moldings are used, then mechanical properties and swelling resistance are improved, but low-temperature flexibility deteriorates below -30°C

Engineering Contradiction:

Improvemechanical propertiesVSAvoidlow-temperature flexibility

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent changes the chemical composition parameters by introducing specific plasticizers (dialkyl cyclohexanedicarboxylates) and internal mold release agents into the polyester polyurethane system. This modifies the molecular structure and intermolecular forces, allowing the material to maintain flexibility at low temperatures while preserving the mechanical strength provided by the polyester base

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system by combining polyester polyol with specific additives including dialkyl cyclohexanedicarboxylates and internal mold release agents. This composite approach allows the base polyester polyurethane to provide mechanical strength while the added compounds prevent rigidification at low temperatures, resolving the contradiction between strength and flexibility

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If rubber soles are used in extremely low temperatures, then flexibility is improved, but specific gravity and thermal conductivity increase

Engineering Contradiction:

Improveflexibility at low temperatureVSAvoidspecific gravity

Core Design Contradiction:

Ease of operationVSWeight of moving object

Solution Approach 1:

The patent modifies the density parameter by using a foam structure with controlled cell formation. The introduction of blowing agents and specific additives creates a cellular structure that reduces the overall density of the molding while maintaining the flexibility needed for low-temperature applications, thus achieving lightweight flexibility without the high specific gravity of solid rubber

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If rubber soles are used in extremely low temperatures, then flexibility is improved, but thermal insulation performance deteriorates

Engineering Contradiction:

Improveflexibility at low temperatureVSAvoidthermal insulation

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The invention employs a porous foam structure with controlled cell sizes and distributions. The cellular structure traps air pockets that provide thermal insulation, while the cell walls maintain flexibility at low temperatures. This porous architecture allows the material to simultaneously achieve flexibility in cold conditions and thermal insulation performance, resolving the contradiction between these two properties

Inventive Principle:

Principle #31Porous materials

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 resulting polyurethane moldings demonstrate excellent elastic properties and flexibility at temperatures below −40°C, with densities suitable for practical applications, such as shoe soles and other footwear, while maintaining mechanical integrity and insulating properties.

Implementation Method 1

The use of plasticizers in polyurethanes is known. Thus, for example, WO 2009/065826 describes the use of dialkyl cyclohexanedicarboxylates in the production of polyester-based polyurethane shoe soles.

Methodology Applied

Scientific EffectPlasticization:

Implementation Method 2

organic polyisocyanates are mixed with (b) compounds having at least two hydrogen atoms which are reactive toward isocyanate, comprising polyester polyol

Methodology Applied

Scientific EffectPolymerization:

Implementation Method 3

Moldings composed of foamed polyurethanes are known and can be used for a variety of applications, for example as shoe soles.

Methodology Applied

Scientific EffectFoam formation: Foam

Data Source

PatentUS10336877B2Molded polyurethane bodies with excellent flexibility at low temperature

Publication Date: 2019.07.02 BASF SE

AI summary

The present invention relates to a process for producing polyurethane moldings, wherein (a) organic polyisocyanates are mixed with (b) one or more compounds having at least two hydrogen atoms which are reactive toward isocyanate, comprising polyester polyol, (c) blowing agent, (d) catalyst, and (e) propylene carbonate and compounds selected from the group consisting of at least one compound of the general formula (I) and a compound of the formula (II), to give a reaction mixture, introduced into a mold and allowed to react to give a polyurethane molding. The present invention further relates to polyurethane moldings obtainable by such a process and also the use of these moldings as steering wheels, seats, armrests and in particular as shoe soles.