Polyurea Additive Manufacturing Viscosity Control

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Solution Overview

Problem

Existing additive manufacturing methods struggle to achieve strong interlayer bonding and high filler content without compromising the viscosity and reaction rate of coreactive materials.

Innovation Solution

The method involves using a two-component progressive cavity pump to extrude a reactive additive manufacturing composition comprising a polyisocyanate prepolymer and a polyamine prepolymer, which are mixed in-line to achieve a reactive composition with controlled viscosity and reaction rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high filler content is used in coreactive materials, then mechanical and electrical properties are improved, but viscosity increases making deposition difficult

Engineering Contradiction:

Improvemechanical propertiesVSAvoidviscosity

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent adjusts the viscosity parameters of the coreactive components by selecting specific polyol and polyisocyanate combinations with controlled molecular weights and functional groups. This allows high filler content (improving mechanical properties) while maintaining viscosity within the optimal range for additive manufacturing deposition

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates composite coreactive materials by combining polyols, polyisocyanates, and fillers in specific ratios. The polyol-polyisocyanate matrix serves as a binder that distributes filler particles uniformly, achieving high filler content without excessive viscosity increase

Inventive Principle:

Principle #40Composite materials

2Strength

If strong interlayer bonding is achieved through rapid crosslinking, then part strength is improved, but reaction rate control becomes difficult affecting deposition stability

Engineering Contradiction:

Improveinterlayer bondingVSAvoidreaction rate control

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent performs preliminary selection of polyol and polyisocyanate components with specific reactivity characteristics before mixing. The components are prepared with controlled functionality and molecular weight to ensure that upon mixing, the crosslinking reaction proceeds at a controlled rate that allows stable deposition while achieving strong interlayer bonding

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent controls the reaction rate by adjusting parameters such as the NCO:OH ratio, component molecular weights, and addition of catalysts or inhibitors. This enables tuning the crosslinking speed to match the deposition rate, ensuring reliable layer formation with strong bonding

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If two-component mixing system is used to control reaction rate, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:

Improvereaction rate controlVSAvoidmixing system

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the coreactive material into two separate components (polyol component and polyisocyanate component) that are stored and delivered separately. This segmentation allows independent control of each component's flow and mixing ratio, achieving precise reaction rate control while using standard dual-component dispensing equipment

Inventive Principle:

Principle #1Segmentation

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

This approach enables the creation of strong, high-filler-content parts with improved mechanical and electrical properties, as well as enhanced solvent and thermal resistance, by controlling the interlayer crosslinking and maintaining a stable viscosity during deposition.

Implementation Method 1

a first component comprising a polyisocyanate prepolymer and a first viscosity; and a second component comprising a polyamine prepolymer and a second viscosity, wherein the first viscosity is within ±20% of the second viscosity

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding