Photocurable Composition for 3D Printing with Non-Coherent UV
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Solution Overview
Problem
Current rapid prototyping techniques using laser radiation for producing three-dimensional articles face limitations in speed and property stability, with laser-based systems producing parts that are often brittle and prone to shrinkage, while non-laser methods lack the mechanical properties of thermoplastic polymers.
Innovation Solution
Development of photocurable compositions using a non-coherent radiation source with specific curable components that cure rapidly and exhibit low shrinkage, achieving properties comparable to conventional thermoplastic polymers, including high tensile strength, modulus, and fracture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If laser radiation is used for rapid prototyping, then curing speed is improved, but the produced parts become brittle and prone to shrinkage
Solution Approach 1:
The patent changes the radiation parameter from coherent laser radiation to non-coherent UV radiation, which fundamentally alters the curing mechanism and eliminates the brittleness and shrinkage issues while maintaining fast curing speeds through optimized photopolymer composition
Solution Approach 2:
The patent uses composite photopolymer formulations combining multiple monomers and oligomers (acrylates, epoxies, silanes) with specific functional groups that work synergistically to achieve both fast curing and excellent mechanical properties with minimal shrinkage
2Productivity
If non-coherent radiation source is used, then production speed is improved, but mechanical properties are insufficient
Solution Approach 1:
The patent optimizes the chemical composition parameters of the photopolymer, including monomer ratios, oligomer types, and photoinitiator selection, to achieve rapid curing with non-coherent UV radiation while attaining mechanical properties comparable to thermoplastics
Solution Approach 2:
The patent employs composite photopolymer systems with multiple curable components (acrylates, epoxies, silanes) that provide both rapid cure kinetics under non-coherent UV radiation and superior mechanical properties including high tensile strength and fracture resistance
3Loss of time
If fast-curing polymers are used, then curing time is reduced, but shrinkage increases and accuracy degrades
Solution Approach 1:
The patent carefully adjusts the chemical composition parameters including the ratio of low-viscosity to high-viscosity monomers, the selection of photoinitiators with optimal absorption spectra, and the inclusion of shrinkage-compensating components to achieve fast curing with minimal shrinkage and high dimensional accuracy
Solution Approach 2:
The patent incorporates components and formulation strategies that preemptively counteract shrinkage effects during the curing process, such as using monomers with complementary shrinkage characteristics and optimizing crosslink density to maintain dimensional stability while achieving rapid cure
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 use of non-coherent radiation with optimized photocurable compositions enables the production of three-dimensional articles with superior mechanical properties and reduced shrinkage, enhancing both speed and stability, allowing for faster production of high-performance parts with thermoplastic-like characteristics.
Implementation Method 1
The first component is photocurable and is such that, when cured in the presence of a photocuring initiator by exposure to UV radiation
Data Source
AI summary
An optical moulding process is disclosed comprising the sequential steps of: (a)(y) forming a layer of a photocurable composition; and (bXz) irradiating selected areas of the composition in the layer with radiation from a radiation source, thereby curing the composition in said selected areas and repeating the steps a) and b) on top of an earlier cured layer to form a three dimensional structure, wherein the radiation source used in step b) is a non-coherent source of radiation and wherein the photocurable composition comprises at least two curable components: (i) 45%-95% (and preferably at least 50%, more preferably at least 60%, e.g. at least 70%) by weight of the total curable components in the composition is a first component that is photocurable and that is such that, when cured in the presence of a photocuring initiator by exposure to UV radiation having an energy of 30 mJ/cm2, at least 90% of the component is cured within 50 milliseconds; and (ii) 5% to 55% (and preferably 10-40%, more preferably 15 to 30%, e.g. about 20%) by weight of the total curable components in the composition is a second component that results in the composition, on curing, shrinking, in a linear direction, by less than 3% and preferably that results in the composition having, after cure, a Tg of greater than 50° C., preferably at least 100° C. and more preferably at least 120° C.