Over-Indexed Thermoplastic Polyurethane Elastomer Crosslinking

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Solution Overview

Problem

Current thermoplastic polyurethane elastomers used in applications like golf balls and other durable articles face challenges with scuff resistance and durability, requiring complex manufacturing processes and having inferior quality due to hygroscopic isocyanate moieties that react with water, leading to inconsistent performance.

Innovation Solution

A method for producing an over-indexed, optionally cross-linked thermoplastic polyurethane elastomer precursor with a stoichiometric excess of isocyanate moieties, using a mixture of unsaturated diols, chain extenders, and a free-radical initiator to create cross-links in the hard segments, which undergoes a dual cure process to form a durable and scuff-resistant polyurethane/urea hybrid.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermoset polyurethane elastomers are used to improve scuff resistance and durability, then the article becomes more resistant to scuffing and more durable, but the manufacturing process becomes more complex and less efficient

Engineering Contradiction:

Improvescuff resistanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the chemical composition parameters by incorporating allyl groups into the polyol structure, enabling crosslinking reactions that transform the material properties while maintaining thermoplastic processing capabilities. This parameter change allows achieving thermoset-like durability with thermoplastic manufacturing simplicity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material system combining thermoplastic polyurethane with crosslinking agents (allyl groups and peroxide). This composite approach integrates the ease of thermoplastic processing with the durability of crosslinked networks, resolving the contradiction between manufacturing simplicity and scuff resistance

Inventive Principle:

Principle #40Composite materials

2Productivity

If thermoplastic polyurethane is used to simplify manufacturing and enable recycling, then the manufacturing process becomes more efficient and recycling is enabled, but the scuff resistance and durability are reduced

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidscuff resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent incorporates crosslinking agents (allyl groups) and initiators (peroxide) into the thermoplastic polyurethane matrix in advance. These components are pre-mixed and ready to react, allowing the material to be processed as a thermoplastic first, then crosslinked later to achieve enhanced durability without compromising manufacturing efficiency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent modifies the chemical structure by adding allyl-functional groups to the polyol chains, changing the material's reactivity parameters. This allows the material to maintain thermoplastic processability at standard conditions while enabling crosslinking under specific conditions (heat, peroxide catalyst) to achieve improved scuff resistance

Inventive Principle:

Principle #35Parameter changes

3Reliability

If over-indexed thermoplastic polyurethane is manufactured to improve durability, then the article becomes more durable and scuff-resistant, but the isocyanate moieties become hygroscopic and react with water, leading to inferior quality

Engineering Contradiction:

ImprovedurabilityVSAvoidhygroscopic reaction with water

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful hygroscopic reaction of excess isocyanate with water into a beneficial crosslinking mechanism. By introducing allyl groups and peroxide initiators, the unreacted isocyanate moieties that would normally degrade the material are instead channeled into controlled crosslinking reactions, improving durability while eliminating the quality problems caused by water reaction

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces peroxide as an intermediary substance that mediates between the excess isocyanate moieties and the allyl groups. The peroxide initiates crosslinking reactions between these components, providing a controlled pathway that prevents the uncontrolled reaction with water and transforms the problematic excess isocyanate into a durability-enhancing crosslinked network

Inventive Principle:

Principle #24Intermediary (Mediator)

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 thermoplastic polyurethane elastomer exhibits improved toughness, durability, and scuff resistance, reducing manufacturing complexity and enhancing the quality of articles such as golf balls and other durable products.

Implementation Method 1

using a mixture of unsaturated diols, chain extenders, and a free-radical initiator to create cross-links in the hard segments

Methodology Applied

Scientific EffectFree-radical polymerization: Photopolymerisation

Implementation Method 2

These isocyanate moieties are available for reaction with water in the second of a two-step curing process. The resultant polyurethane/urea hybrid

Methodology Applied

Scientific EffectHydrolysis reaction: Hydrolysis

Data Source

PatentEP2800768B1Method for making over-indexed thermoplastic polyurethane elastomer precursor and thermoplastic polyurethane elastomer made from the precursor

Publication Date: 2017.11.15 FENG TAY ENTERPRISE CO LTD

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AI summary

A method for making over-indexed thermoplastic polyurethane elastomer precursor having unreacted isocyanate moities is presented, the method comprising: combining reactants and reacting them to form an over-indexed thermoplastic polyurethane elastomer precursor; cooling; pelletizing; drying; and packaging it in moisture-resistant packaging. A method for making over-indexed thermoplastic polyurethane elastomer, and a method for making an article therefrom are also presented.