Core-Shell Polymer Strands for 3D Printing
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Solution Overview
Problem
Thermoplastic moldings produced using the melt-laminated process often suffer from defects such as uneven shrinkage, lack of strength in certain directions, and poor layer adhesion, which limits their application and durability, especially due to the use of amorphous materials that lack sufficient strength, UV resistance, and dimensional stability.
Innovation Solution
The development of core-shell polymer strands with specific additives in the core and shell, such as lithium chloride, ethylene-bis-stearamide, and spherical fillers, which improve layer adhesion and dimensional stability, allowing for the production of distortion-free, heat-resistant thermoplastic moldings using the melt layer process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If round fillers such as Neuburg silica, attapulgite, glass balls are used to reduce distortion, then distortion-free molded bodies are achieved, but layer adhesion is destroyed
Solution Approach 1:
The strand is divided into core and shell components, with spherical fillers concentrated in the core and adhesion promoters in the shell. This segmentation allows each component to fulfill its specific function without interfering with the other, resolving the contradiction between dimensional stability and layer adhesion.
Solution Approach 2:
Different regions of the strand are given different properties: the core contains spherical fillers for distortion control, while the shell contains adhesion promoters for strong layer bonding. This local differentiation of material properties enables simultaneous achievement of both dimensional stability and layer adhesion.
2Ease of manufacture
If amorphous materials such as ABS, ASA, PC/ABS are used for easy processing, then ease of manufacture is improved, but strength and UV resistance are insufficient
Solution Approach 1:
The strand combines amorphous thermoplastic matrix with dispersed spherical filler particles to create a composite material that maintains the processability of amorphous materials while gaining the dimensional stability and mechanical strength characteristics of filled systems.
3Adaptability or versatility
If functional additives are used in one-component strands for surface functionalization, then functional properties are achieved, but layer adhesion is worsened and excessive additive is required
Solution Approach 1:
The strand is segmented into core and shell, with functional additives placed in the shell layer. This allows functional properties to be achieved with minimal additive quantities while the core maintains structural integrity and the shell provides both function and adhesion.
Solution Approach 2:
Functional properties are localized to the shell region where they are needed for surface functionality, while the core maintains its structural role. This local placement of functional additives eliminates the need for excessive additive usage and prevents adhesion problems.
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 core-shell strands enable the creation of thermoplastic moldings with enhanced layer adhesion, heat resistance, and mechanical properties, including improved tensile strength and dimensional stability, while allowing for additional functional properties like antibacterial and UV protection, even in non-heated additive manufacturing systems.
Implementation Method 1
The irregular shrinkage occurs during the melt layer process when individual strands of the resulting molded body cool unevenly quickly. Strands that cool quickly shrink more than strands that cool slowly.
Implementation Method 2
a nucleating agent, such as PA 2.2
Implementation Method 3
The layers consist of individual strands welded together using the fused layer process
Data Source
Figure 1~2b
Figure 3
Figure 4~5
AI summary
Polymer strands based on thermoplastic organic polymers for the production of heat-resistant molded parts using 3D printing are disclosed. The strands have a core/sheath structure. The thermoplastic polymers of the core and/or sheath are blended with at least one additive A, which improves layer adhesion in the z-direction of the molded parts, wherein additive A is selected from the group consisting of lithium chloride, ethylene bis-stearamide, montan wax, styrene-maleic anhydride copolymers, and polyvinylpyrrolidone, and with at least one additive B, which reduces warping of the molded parts, wherein additive B is a spherical filler selected from the group consisting of Neuburg silica, attapulgite, microhollow glass spheres, microtalc, and thermally pretreated Neuburg silica, or a nucleating agent.