| CPC C09D 5/14 (2013.01) [B33Y 70/10 (2020.01); B65D 81/24 (2013.01); B65D 85/34 (2013.01); C09D 105/00 (2013.01); C09D 127/06 (2013.01); B29C 64/118 (2017.08); B29K 2027/06 (2013.01); B29K 2105/0035 (2013.01); B29K 2105/0038 (2013.01); B29L 2031/712 (2013.01)] | 5 Claims |

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1. A method for preparing an antibacterial and fresh-keeping fruit-packaging material through three-dimensional (3D) printing, comprising the following steps:
(1) preparation of a core layer solution: dissolving gum arabic in deionized water to obtain a gum arabic solution with a mass concentration of 10% to 15%; dissolving pullulan in deionized water to obtain a pullulan solution with a mass concentration of 10% to 15%; subjecting a probiotic to inoculation and cultivation, centrifugation, and resuspension to obtain a bacterial suspension with a bacterial concentration of 109 lg to 1010 lg (CFU/g); and mixing the bacterial suspension, the gum arabic solution, and the pullulan solution in a mass ratio of 1: (3-4): (1-3), and sealing and stirring a resulting mixed solution to obtain the core layer solution;
(2) preparation of a shell layer solution: mixing polyvinyl chloride, a modifier, and a plasticizer, and thoroughly stirring a resulting mixture to obtain the shell layer solution, wherein the polyvinyl chloride, the modifier, and the plasticizer are mixed in a mass ratio of 100: (5-10): (20-30) and the modifier is chlorinated polyethylene; and
(3) preparation of the antibacterial and fresh-keeping fruit-packaging material: with the shell layer solution and the core layer solution as 3D printing solutions, conducting coaxial 3D printing and uniaxial 3D printing as follows:
injecting the shell layer solution obtained in the step (2) and the core layer solution obtained in the step (1) into two syringes, respectively; conducting the coaxial 3D printing with a propulsion rate of the shell layer solution greater than a propulsion rate of the core layer solution to finally obtain a coaxial 3D printing product with a core-shell structure on a bottom plate of a device; and
conducting the uniaxial 3D printing with the shell layer solution alone to form an outer layer on the core-shell structure of the coaxial 3D printing product to obtain the antibacterial and fresh-keeping fruit-packaging material with inner and outer layers, wherein the inner layer is used for keeping fruits fresh and the outer layer is used for protection of the fruits.
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