Flexible 3d printing material with double-layer structure and preparation method

A flexible 3D printing material with a double-layer structure, comprising:

• a TPU coating layer and an inner layer TPU composite material;
• the TPU coating layer is composed of hard TPU, and the inner layer TPU composite material is composed of the following components:
• a flexible TPU and a coupling agent configured to improve interfacial adhesion strength between components;
• wherein the inner layer TPU composite material further comprises a plasticizer, and the plasticizer is configured to improve an overall elongation at break of a material and reduce a hardness;
• the plasticizer is one or more of phthalic acid ester, polyethylene Terephthalate, succinate, or dimethyl isophthalic acid ester;
• wherein the flexible 3D printing material is made of the following components by mass of parts:
• Hard TPU:
• 90-100 parts, flexible TPU:
• 30-70 parts, coupling agent:
• 1.5-3 parts, plasticizer:
• 0.5-2 parts;
• wherein the coupling agent is γ-aminopropyltriethoxysilane;
• wherein a hardness of the hard TPU is 70-75 D, and a hardness of the flexible TPU is 85-95 A.