Curable Polyurethane Resin for Additive Manufacturing
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Solution Overview
Problem
Stereolithographic (SLA) 3D printing techniques produce parts that are brittle due to insufficient elongation and tensile strength, making them unsuitable for consumer items and industrial production, and existing solutions compromise between elongation and tensile strength, often at the cost of reduced potlife, recyclability, and increased printing time.
Innovation Solution
A liquid curable resin comprising cross-linkable polyurethane polymers end-capped with UV and/or heat-induced polymerizable moieties and a reactive diluent, which undergoes phase separation during photopolymerization, resulting in a thermoset elastomeric polymer with distinct glass transition temperatures and enhanced mechanical properties, achieving elongation at break values of >100% and tensile strength of >5 MPa.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If SLA 3D printing is used to produce parts with good tensile strength, then tensile strength is improved, but elongation is insufficient making parts brittle
Solution Approach 1:
The patent uses a composite resin system comprising polyurethane polymers with UV-curable functional groups combined with a reactive diluent. This composite formulation allows the material to achieve both high tensile strength ( >5 MPa) and high elongation (>100%) simultaneously, resolving the contradiction between strength and flexibility in SLA printed parts
Solution Approach 2:
The patent modifies the chemical composition parameters of the resin by incorporating specific polyurethane polymers with controlled molecular weight and functional group content, along with optimized diluent ratios. These parameter changes enable the cured material to exhibit elastomeric properties with both strength and elongation, transforming brittle SLA parts into flexible elastomers
2Adaptability or versatility
If 2 components are mixed during printing to improve elongation, then elongation is improved, but potlife is reduced and printing time is restricted
Solution Approach 1:
The patent segments the resin system into a single-component formulation where the polyurethane polymer with UV-curable groups and the reactive diluent remain separate until curing. This segmentation maintains long potlife and recyclability while enabling high elongation properties in the final cured product, eliminating the need for mixed-component timing constraints
3Manufacturing precision
If SLA printing is used for functional prototypes, then manufacturing precision is improved, but the parts are brittle and not suitable for consumer items
Solution Approach 1:
The patent employs a composite resin system that produces parts with both high manufacturing precision and improved mechanical durability. The polyurethane-based elastomeric polymer provides toughness and flexibility while maintaining the fine surface finish and geometric precision characteristic of SLA printing, making parts suitable for both prototyping and consumer applications
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 solution produces 3D printed objects with improved mechanical properties, including high tensile strength and elongation, suitable for consumer and industrial applications, while maintaining process efficiency and recyclability.
Implementation Method 1
A liquid curable resin comprising cross-linkable polyurethane polymers which are end-capped with UV and/or heat induced polymerizable moieties
Data Source
AI summary
A liquid curable polyurethane based resin comprising a) polyurethane compounds which are functionalized with reactive ethylenically unsaturated moieties, b) at least one reactive diluent compound having at least one ethylenically unsaturated functional group and c) at least one photo-initiator for making polymerized/cured polyurethane based materials having elongation at break values of >100%, preferably >125%, most preferably >150% and a tensile strength of >5 MPa, more preferably >7 MPa, most preferably >10 MPa (both measured according to DIN 53504 S2).