Biodegradable three-dimensional (3D) printing wire having three-layer skin-core structure, and preparation method of biodegradable 3D printing wire

Abstract

The invention relates to a three-dimensional (3D) printing wire, in particular to a biodegradable 3D printing wire having a three-layer skin-core structure, and a preparation method of the biodegradable 3D printing wire. The 3D printing wire comprises three layers, i.e. an inner layer, a middle layer and an outer layer, wherein the inner layer is prepared from poly-L-lactic acid, the middle layer is prepared from 80-90wt% of poly-L-lactic acid and 10-20wt% of a poly-L/D-lactic acid copolymer, and the outer layer is prepared from 65-75wt% of poly-L-lactic acid and 25-35wt% of a poly-L/D-lactic acid copolymer. The preparation method comprises the steps of sequentially adding the materials of the inner layer, the middle layer and the outer layers into corresponding single screw extruders at the inner layer, the middle layer and the outer layer in a wire-drawing device, extruding a wire at the temperature of 160-180 DEG C, and then enabling the extruded wire to be sequentially cooled and molded in four stages so as to obtain the biodegradable 3D printing wire having the three-layer skin-core structure. The biodegradable 3D printing wire having the three-layer skin-core structure is fully biodegradable and has good rigidity, toughness, roundness and glossiness.

Description

technical field [0001] The invention relates to a 3D printing filament, in particular to a biodegradable 3D printing filament with a three-layer skin-core structure and a preparation method thereof. Background technique [0002] In the 1980s, 3D printing was developed and promoted and became increasingly mature, and gradually applied to various fields of society. 3D printing is actually a rapid prototyping technology. It is based on digital model files and uses adhesive materials such as plastics and powdered metals to construct objects by layer-by-layer printing. 3D printing can directly generate objects of any shape from computer graphics data without machining or molds, so that companies no longer consider production process issues when producing components, and any complex shape design can be achieved through 3D printing. 3D printing technology has brought about a worldwide manufacturing revolution, overturned the traditional production process, greatly shortened the pr...

AI Technical Summary

Problems solved by technology

Although these materials are all biodegradable plastics, due to the large difference in molecular composition, the compatibility with polylactic acid is also very poor. When the addition amount is small, the toughening effect is poor. When the addition amount is large, the strength and rigidity of polylactic acid The loss is also relatively large. In order to improve the compatibility between them and polylactic acid, some compatibilizers are generally introduced, but these compatibilizers are also some non-biodegradable plastics, which affect the biodegradability of polylactic acid.

[0008] (3) Introducing liquid plasticizers into polylactic acid, such as acetyl tributyl citrate (ATBC), etc., the compatibility between liquid plasticizers and polylactic acid is poor, the amount of addition is small, and the toughening effect is poor When it is large, the loss of rigidity and strength is large, and the overflow of plasticizer is obvious, and the introduction of liquid plasticizer also makes the processability poor

[0009] Chinese patent CN104448738A discloses a bio-based 3D printing material and its preparation method to solve the problems of the existing 3D printing material polylactic acid with low crystallinity, low ester bond energy in the molecular chain, and easy breakage

This patent introduces thermoplastic polyolefin elastomer (TPO) into polylactic acid to improve the toughness of polylactic acid. Due to the poor compatibility between polyolefin elastomer and polylactic acid, the toughening effect is not good, and polyolefin elastomer is a non-degradable material. , its introduction also affected the biodegradability of PLA

[0011] Chinese patents CN104327470A and CN104356619A introduced 4 to 35% polyacrylate in polylactic acid, and Chinese patent CN104693709A introduced polycarbonate PC in polylactic acid. Although the toughness of polylactic acid has been improved to a certain extent, they have lost their biodegradability

The solvent used in this method is generally dichloromethane, chloroform or a mixture of dichloromethane and chloroform. The above-mentioned solvents are not only highly toxic but also flammable and explosive. This method has high cost and great pollution, and is not suitable for industrialization.

[0014] In the prior art, the preparation of polylactic acid 3D printing filament mainly focuses on the toughening of polylactic acid, but ignores the compatibility between the introduced toughening agent and polylactic acid, whether the introduced toughening agent and compatibilizer are biological Degraded materials, whether the rigidity of polylactic acid is destroyed after toughening, how to ensure the high roundness of printing filament after toughening, etc.