Coreactive Polyurea Compositions for 3D Printing Adhesion
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Solution Overview
Problem
Existing 3D printing methods using thermoplastic materials face challenges with adhesion between layers and stress buildup due to differential thermal expansion, which compromises the integrity of the printed objects.
Innovation Solution
The use of coreactive printing compositions, such as polyurea compositions, formed from a mixture of at least two coreactive components with reactive functional groups, where at least one component comprises a saturated functional group, to enhance layer adhesion and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermoplastic material is used for 3D printing, then the material can be extruded and shaped, but adhesion between layers is poor and stress builds up due to differential thermal expansion
Solution Approach 1:
The patent changes the fundamental parameter of material chemistry by using coreactive compositions with complementary functional groups (isocyanate and hydroxyl) that form covalent bonds, transforming the adhesion mechanism from physical to chemical bonding. This resolves the contradiction by providing strong interlayer adhesion while eliminating stress buildup from thermal expansion.
Solution Approach 2:
The invention uses composite material systems consisting of two separate components (isocyanate-containing and hydroxyl-containing) that react together to form the final structure. This composite approach allows the material to exhibit both ease of deposition and strong bonding, resolving the contradiction between processability and structural integrity.
2Ease of manufacture
If thermoplastic material is extruded through heated nozzle, then layers can be built successively, but differential thermal expansion causes stress buildup
Solution Approach 1:
The patent changes the curing mechanism from thermal to chemical reaction-based. By using coreactive compositions that cure through covalent bond formation rather than cooling, the material avoids differential thermal expansion stresses while maintaining ease of successive layer deposition.
Solution Approach 2:
The invention utilizes a phase transition from liquid reactants to solid crosslinked network through chemical reaction rather than thermal cooling. This eliminates the thermal expansion/contraction cycle that causes stress, while still allowing successive layer building through controlled material deposition.
3Strength
If coreactive composition is used to improve adhesion, then covalent bonds form between layers, but the composition must maintain specific rheological properties during printing
Solution Approach 1:
The patent employs dynamic rheological properties where the composition remains fluid and printable during deposition, then transitions to a rigid crosslinked structure after layer formation. This time-dependent behavior allows easy manufacturing during printing while achieving strong adhesion in the final product, resolving the contradiction between processability and bond strength.
Solution Approach 2:
The invention incorporates preliminary rheological optimization of the coreactive composition to ensure proper flow and deposition characteristics before the chemical reaction begins. This preliminary control of viscosity and flow properties enables successful printing while the covalent bonding provides the final strong adhesion, resolving the contradiction between ease of printing and bond strength.
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 coreactive compositions achieve strong interlayer adhesion and improved structural integrity by forming covalent bonds between layers, reducing stress buildup, and maintaining the desired shape of the printed objects.
Implementation Method 1
forming covalent bonds between layers
Implementation Method 2
at least one of the first functional group and the second functional group comprises a saturated functional group
Data Source
AI summary
Methods of printing a three-dimensional object using co-reactive components are disclosed. Thermosetting compositions for three-dimensional printing are also disclosed.