Induced Crystallized Polymer Powders for Additive Manufacturing

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current additive manufacturing methods using powder-based techniques, such as SLS and MJF, face limitations due to high residual stresses and the need for volatile organic solvents, which restrict the use of thermoplastic polymers for producing large or complex parts with desired properties like high strength, toughness, and optical transparency.

Innovation Solution

The method involves permeating carbon dioxide into polymers with carbonyl, sulfur oxide, or sulfone groups to induce crystallization in the solid phase, allowing for the co-crystallization of polymer blends without solvents, and forming induced crystallized polymer particles suitable for additive manufacturing, which can be used to create high-performance articles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If volatile organic solvents are used to induce crystallization in polymers, then crystallization can be achieved, but the solvents leave traces that limit use in food contact and other applications

Engineering Contradiction:

ImprovecrystallizationVSAvoidsolvent traces

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

Carbon dioxide serves as an intermediary substance that enables crystallization without remaining as a harmful trace. The CO2 permeates the polymer, facilitates crystal formation, and then evaporates completely, leaving no residue that would contaminate food contact surfaces or other sensitive applications.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The method utilizes phase transitions of carbon dioxide (between supercritical fluid, gas, and liquid states) to control the crystallization process. By cycling CO2 through these phases, the polymer undergoes controlled crystallization followed by complete evaporation of the CO2, eliminating solvent traces.

Inventive Principle:

Principle #36Phase transitions

2Reliability

If semi-crystalline polymers are used for additive manufacturing, then residual stresses are reduced, but the polymers limit the use of high performance materials like polyamides

Engineering Contradiction:

Improveresidual stress minimizationVSAvoidpolymer selection

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The method changes the physical and chemical parameters of the polymer by introducing CO2 permeation and induced crystallization. This allows amorphous high-performance polymers to achieve crystalline properties beneficial for reducing residual stress, while maintaining the versatility to use various polymer types including polyamides, polycarbonates, and polysulfones.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If crystalline or semicrystalline thermoplastic polymers are used, then residual stresses are minimized, but the window between melting temperature and recrystallization temperature must be sufficiently large

Engineering Contradiction:

Improveresidual stress minimizationVSAvoidmelting and recrystallization temperature window

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The CO2 permeation and induced crystallization occur as a preliminary action before the additive manufacturing process. This pre-crystallization prepares the polymer with favorable stress characteristics while establishing a controlled nucleation structure that influences subsequent melting and recrystallization behavior during printing.

Inventive Principle:

Principle #10Preliminary action

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 production of high-strength, tough, and high-temperature-resistant articles with controlled crystallinity, avoiding the use of volatile organic solvents and minimizing residual stresses, thus expanding the range of applications including biocompatible, electrical, and food-contact materials.

Implementation Method 1

permeating the carbon dioxide into the polymer for a crystalizing time sufficient to induce crystallization

Methodology Applied

Scientific EffectPermeation: Permeation

Implementation Method 2

induce crystallization in the solid phase

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Implementation Method 3

additives that dissolve in the carbon dioxide may be permeated and incorporated into the polymer

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS12180343B2Thermoplastic polymers and method to make them

Publication Date: 2024.12.31 LUMAS POLYMERS LLC

AI summary

Polymer powders useful for additive manufacturing may be made by contacting carbon dioxide and a crystallizable polymer having at least one carbonyl, sulfur oxide or sulfone group; permeating the carbon dioxide into the polymer for a crystallizing time sufficient to induce crystallization forming an induced crystalized polymer; removing the carbon dioxide; and forming induced crystalized polymer particles having a D90 particle size of at most 300 micrometers and average particle size of 1 micrometer to 100 micrometers equivalent spherical diameter. The carbon dioxide is desirably supercritical carbon dioxide for at least a portion of the crystallizing time. The polymer powders upon heating during additive manufacturing may result in a polymer having less crystallinity or become amorphous.