CN-121973522-A - Preservative film and preparation method thereof

CN121973522ACN 121973522 ACN121973522 ACN 121973522ACN-121973522-A

Abstract

The invention belongs to the technical field of food fresh-keeping materials, and particularly relates to a fresh-keeping film and a preparation method thereof, wherein the fresh-keeping film comprises a resin-based film, an ethylene regulation and control composite functional layer and a selective ventilation protective layer which are sequentially laminated; the ethylene regulation and control composite functional layer is composed of porous polymer microspheres with core-shell structures, the porous polymer microspheres comprise porous core bodies, ethylene removal active components are loaded in the porous core bodies, and functional shell layers are arranged on the outer surfaces of the porous core bodies; according to the invention, the active components are removed through the porous polymer microsphere with a core-shell structure, so that the stability and the utilization efficiency of the ethylene removal components are improved, the ethylene concentration in the package can be continuously reduced, the polyvinylidene fluoride microporous filter membrane is used as a functional shell layer, the migration of the active components is effectively limited, the use safety is improved, and the antibacterial active components are introduced into the ethylene regulation composite functional layer, so that the antibacterial active components have an inhibition effect on the surfaces of fruits and vegetables and microorganisms in the package environment.

Inventors

YU JIANJUN
WANG XIAOLI

Assignees

烟台金沣供应链科技有限公司

Dates

Publication Date: 20260505
Application Date: 20260206

Claims (8)

1. The preservative film is characterized by comprising a resin-based film, an ethylene regulation and control composite functional layer and a selective ventilation protective layer which are sequentially laminated, wherein the ethylene regulation and control composite functional layer is composed of porous polymer microspheres with a core-shell structure, the porous polymer microspheres comprise porous core bodies, ethylene removal active components are loaded in the porous core bodies, and functional shell layers are arranged on the outer surfaces of the porous core bodies.
2. The preservative film according to claim 1, wherein the ethylene removal active component comprises 40-55%, 15-30% and 15-35% of potassium permanganate, methylcyclopropene and metal oxide catalyst.
3. The preservative film according to claim 2, wherein the porous core is made of one of acrylic acid ester copolymer, polylactic acid and bio-based polymer.
4. The preservative film according to claim 3, wherein the functional shell layer is a polyvinylidene fluoride microporous filter film.
5. The preservative film according to claim 4, wherein the ethylene regulation and control composite functional layer further comprises an antibacterial active component, the antibacterial active component comprises nano silver, zinc oxide and natural antibacterial substances, and the mass percentages of the nano silver, the zinc oxide and the natural antibacterial substances are 5-20%, 20-45% and 35-60%, respectively.
6. A preservative film according to claim 5 wherein the selectively breathable protective layer is expanded polytetrafluoroethylene and the selectively breathable protective layer allows ethylene and oxygen to permeate therethrough while blocking liquid water and solid particles.
7. The preservative film according to claim 6, wherein the resin-based film has a thickness of 8-20 m, the ethylene-controlled composite functional layer has a thickness of 1-6 m, and the selective air-permeable protective layer has a thickness of 1-5 m.
8. A method for preparing a preservative film according to claim 7, which is characterized by mainly comprising the following steps: Step one, preparing porous polymer microspheres with a communication pore structure by adopting one of acrylic ester copolymers, polylactic acid or bio-based polymers through an emulsion polymerization process, wherein the porous polymer microspheres are used as porous nuclear bodies; Adding a porous nuclear body into the dispersion system, and carrying out dipping treatment under the stirring condition to enable an ethylene removal active component to be attached and fixed in a pore structure of the porous nuclear body, so as to obtain the porous nuclear body loaded with the ethylene removal active component; Step three, placing a porous nuclear body loaded with ethylene to remove active components into a film-forming solution containing polyvinylidene fluoride, and forming a polyvinylidene fluoride microporous filter film on the outer surface of the porous nuclear body loaded with ethylene to remove the active components through a phase separation process to obtain porous polymer microspheres with a core-shell structure; Step four, mixing porous polymer microspheres with a core-shell structure with antibacterial active components to obtain a mixture, wherein the antibacterial active components comprise nano silver, zinc oxide and natural antibacterial substances; And fifthly, covering the ethylene regulation and control composite functional layer with a bulked polytetrafluoroethylene material, and forming a selective ventilation protective layer through a hot-pressing process, thereby preparing the preservative film.

Description

Preservative film and preparation method thereof Technical Field The invention belongs to the technical field of food fresh-keeping materials, and particularly relates to a fresh-keeping film and a preparation method thereof. Background Fresh fruits and vegetables still keep breathing during storage and circulation after picking, and ethylene gas is continuously released. Ethylene is used as a plant endogenous hormone, and after a certain concentration is reached, the ripening and aging processes of fruits and vegetables are obviously accelerated, so that the fruits and vegetables soften, rot and degrade, and the shelf life is shortened. The existing preservative film is mostly made of single resin material, mainly plays a physical isolation role, lacks effective regulation and control capability on ethylene gas, is easy to cause ethylene concentration accumulation in the package and accelerates fruit and vegetable deterioration. Meanwhile, microorganisms on the surfaces of fruits and vegetables and in the packaging environment can cause spoilage problems, and further influence the food safety and the fresh-keeping effect. In order to solve the problems, the prior art attempts to introduce ethylene adsorbent or antibacterial component into fresh-keeping materials, but has the defects of easy migration of active components, insufficient stability, limited action time and the like. Disclosure of Invention In order to solve the problems, the invention provides a preservative film and a preparation method thereof. The preservative film comprises a resin-based film, an ethylene regulation and control composite functional layer and a selective ventilation protective layer which are sequentially laminated, wherein the ethylene regulation and control composite functional layer is composed of porous polymer microspheres with a core-shell structure, the porous polymer microspheres comprise porous core bodies, ethylene removal active components are loaded in the porous core bodies, and functional shell layers are arranged on the outer surfaces of the porous core bodies. Further, the ethylene removal active component comprises 40-55% by mass, 15-30% by mass and 15-35% by mass of potassium permanganate, methylcyclopropene and metal oxide catalyst. Further, the porous core body is made of one of acrylic copolymer, polylactic acid and bio-based polymer. Further, the functional shell layer is a polyvinylidene fluoride microporous filter membrane. Further, the ethylene regulation and control composite functional layer also comprises an antibacterial active component, wherein the antibacterial active component comprises nano silver, zinc oxide and natural antibacterial substances, and the mass percentages of the nano silver, the zinc oxide and the natural antibacterial substances are 5-20%, 20-45% and 35-60% respectively. Further, the material of the selective air-permeable protective layer is expanded polytetrafluoroethylene, and the selective air-permeable protective layer allows ethylene and oxygen to permeate and blocks liquid water and solid particles. Further, the thickness of the resin-based film is 8-20 m, the thickness of the ethylene-controlled composite functional layer is 1-6 m, and the thickness of the selective ventilation protective layer is 1-5 m. The scheme also discloses a preparation method of the preservative film, which mainly comprises the following steps: Step one, preparing porous polymer microspheres with a communication pore structure by adopting one of acrylic ester copolymers, polylactic acid or bio-based polymers through an emulsion polymerization process, wherein the porous polymer microspheres are used as porous nuclear bodies; Adding a porous nuclear body into the dispersion system, and carrying out dipping treatment under the stirring condition to enable an ethylene removal active component to be attached and fixed in a pore structure of the porous nuclear body, so as to obtain the porous nuclear body loaded with the ethylene removal active component; Step three, placing a porous nuclear body loaded with ethylene to remove active components into a film-forming solution containing polyvinylidene fluoride, and forming a polyvinylidene fluoride microporous filter film on the outer surface of the porous nuclear body loaded with ethylene to remove the active components through a phase separation process to obtain porous polymer microspheres with a core-shell structure; Step four, mixing porous polymer microspheres with a core-shell structure with antibacterial active components to obtain a mixture, wherein the antibacterial active components comprise nano silver, zinc oxide and natural antibacterial substances; And fifthly, covering the ethylene regulation and control composite functional layer with a bulked polytetrafluoroethylene material, and forming a selective ventilation protective layer through a hot-pressing process, thereby preparing the preservative film. The beneficial effects obtained