CN-122009657-A - PE (polyethylene) composite fresh-keeping bag for preventing and controlling cold chain temperature loss and preparation method and application thereof

CN122009657ACN 122009657 ACN122009657 ACN 122009657ACN-122009657-A

Abstract

The invention discloses a PE composite fresh-keeping bag for preventing and controlling cold chain temperature loss, a preparation method and application thereof, wherein the fresh-keeping bag is a polyethylene film with a three-layer co-extrusion composite structure, and comprises a heat insulation layer A, a gas regulating layer B and a dehumidifying layer C from outside to inside, wherein the heat insulation layer A is formed by blending low-density polyethylene LDPE and heat insulation functional filler, the gas regulating layer B is formed by blending linear low-density polyethylene LLDPE and gas adsorption regulating functional filler, the dehumidifying layer C is formed by blending low-density polyethylene LDPE and hygroscopic functional filler, and the preparation method of the PE composite fresh-keeping bag for preventing and controlling cold chain temperature loss comprises the following steps of (1) preparing functional master batch, (2) three-layer co-extrusion blowing film, (3) post-treatment. The invention also discloses application of the PE composite fresh-keeping bag in perishable fruit and vegetable packaging, and has the advantages of active control and multifunctional cooperation, intelligent regulation, advanced and reliable processing technology, safety, environmental protection and the like.

Inventors

XIAO NAIYU
ZHONG JIAYU
ZHONG YUNYUN
ZHANG HAOJIE
HU XINKUAN
YANG YANG
CHEN GUOJIAN
WANG HONGLEI
ZHANG XUEQIN
LUO WENHAN

Assignees

仲恺农业工程学院

Dates

Publication Date: 20260512
Application Date: 20251027

Claims (10)

1. The PE composite fresh-keeping bag for preventing and controlling cold chain temperature loss is characterized by comprising a three-layer co-extrusion composite structure polyethylene film, and sequentially comprising a heat insulation layer A, a gas regulating layer B and a dehumidifying layer C from outside to inside, wherein the heat insulation layer A is formed by blending low-density polyethylene LDPE and heat insulation function filler, the gas regulating layer B is formed by blending linear low-density polyethylene LLDPE and gas adsorption regulating function filler, and the dehumidifying layer C is formed by blending low-density polyethylene LDPE and moisture absorption function filler.
2. The PE composite freshness protection package for preventing and controlling cold chain temperature loss according to claim 1 is characterized in that the heat insulation function filler accounts for 5-20% of the heat insulation layer A, the gas adsorption adjusting function filler accounts for 10-25% of the gas adjusting layer B, and the moisture absorption function filler accounts for 5-20% of the moisture absorption layer C.
3. The PE composite freshness protection package for preventing and controlling cold chain temperature loss according to claim 1, wherein the heat insulation function filler is selected from one or a mixture of more of nano silica aerogel, vacuum glass beads, hollow ceramic beads, mica powder and cork powder.
4. The PE composite freshness protection package for preventing and controlling cold chain temperature loss according to claim 1, wherein the gas adsorption adjusting function filler is selected from one or a mixture of several of 4A type zeolite molecular sieve, 13X type zeolite molecular sieve, zeolite, carbon molecular sieve, metal organic frame materials MOFs, activated alumina and diatomite.
5. The PE composite freshness protection package for preventing and controlling cold chain temperature loss according to claim 1, wherein the moisture absorption functional filler is selected from one or a mixture of several of sodium polyacrylate, potassium polyacrylate, sodium polyacrylate grafted starch, sodium carboxymethylcellulose CMC, sodium alginate, kaolin and high molecular absorbent resin SAP.
6. The PE composite freshness protection package for preventing and controlling cold chain temperature loss according to claim 1, wherein the thickness ratio of the heat insulation layer A to the air conditioning layer B to the dehumidifying layer C is (15-30): 10-20): 15-30.
7. The method for preparing the PE composite freshness protection package for preventing and controlling cold chain temperature loss damage according to any one of claims 1 to 6, which is characterized by comprising the following steps: (1) Preparing functional master batches, namely respectively mixing the heat insulation functional filler with LDPE, the gas adsorption adjusting functional filler with LLDPE and the moisture absorption functional filler with LDPE at high speed, and then carrying out melt extrusion granulation to prepare functional master batches of a heat insulation layer A, a gas adjusting layer B and a moisture removing layer C; (2) Adding the functional master batches in the step (1) into three extruders of three-layer coextrusion film blowing equipment respectively, and preparing a three-layer composite film through melt coextrusion, inflation, cooling, corona treatment and rolling; (3) And (3) post-treatment, namely curing the rolled film, slitting and bagging.
8. The method according to claim 7, wherein the die temperature of the three-layer coextrusion film blowing apparatus in the step (2) is 165-175 ℃, the inflation ratio at inflation is 2.5-3.0:1, and the strength at corona treatment is 38-48 dyne/cm.
9. Use of the PE composite freshness protection package of any one of claims 1-6 in perishable fruit and vegetable packaging.
10. Use of the PE composite freshness protection package of any one of claims 1-6 in perishable fruit and vegetable packaging for cold chain transportation, sales and home storage applications.

Description

PE (polyethylene) composite fresh-keeping bag for preventing and controlling cold chain temperature loss and preparation method and application thereof Technical Field The invention belongs to the technical field of food packaging materials, and particularly relates to a PE (polyethylene) composite fresh-keeping bag for preventing and controlling cold chain temperature loss and damage, and a preparation method and application thereof. Background Cold chain logistics is a key technology for guaranteeing the quality of perishable fruits and vegetables and prolonging the shelf life. However, in actual operation, the phenomenon of "desuperheating" (Temperature Abuse) is difficult to avoid, and often occurs in links such as loading and unloading, sales terminals or home refrigerators. The fluctuation of the ambient temperature caused by the temperature drop can cause a series of chain deterioration effects that firstly, the sudden temperature rise can rapidly accelerate the respiration intensity (respiratory burst) of fruits and vegetables, a large amount of respiratory heat (field heat) and CO 2 are generated, a large amount of O 2 is consumed, and secondly, when the temperature drops back, the higher absolute humidity in the bag is extremely easy to reach a supersaturated state due to the rise of the dew point temperature, and a large amount of condensed water is generated. The condensed water not only provides a temperature bed for microorganism breeding to cause rot, but also takes away a large amount of heat in the evaporation process to cause secondary cold damage to fruits and vegetables. The prior art mostly adopts common Polyethylene (PE) fresh-keeping bags or perforated microporous films. Although the common PE bag has certain barrier property, the PE bag has poor moisture permeability and air permeability, and can rapidly accumulate CO 2 and moisture under the condition of temperature removal, thereby forming the adverse conditions of high humidity, high CO 2 and low O 2, and aggravating physiological disorder and microbial spoilage. The microporous membrane regulates gas through physical openings, but the regulation effect is passive, single and uncontrollable, cannot cope with the severe change of the respiratory rate, has no heat insulation and active dehumidification functions, and cannot fundamentally solve the three core problems of condensation, gas unbalance and temperature impact caused by temperature removal. Therefore, the multifunctional intelligent package capable of actively responding and relieving the temperature loss is developed, integrates heat insulation, intelligent air conditioning and efficient dehumidification, and has great significance in improving the elasticity of a cold chain and reducing the postharvest loss of fruits and vegetables. Disclosure of Invention The invention aims to provide a PE composite fresh-keeping bag for preventing and controlling cold chain temperature loss. The invention also aims to provide a preparation method of the PE composite fresh-keeping bag for preventing and controlling cold chain temperature loss. The final object of the invention is to provide the application of the PE composite freshness protection package in perishable fruit and vegetable packaging. The first aim of the invention can be achieved by adopting the following technical scheme that the PE composite fresh-keeping bag for preventing and controlling cold chain temperature loss is a polyethylene film with a three-layer co-extrusion composite structure, and comprises a heat insulation layer A, a gas regulating layer B and a dehumidifying layer C in sequence from outside to inside, wherein the heat insulation layer A is formed by blending low-density polyethylene LDPE and heat insulation function filler, the gas regulating layer B is formed by blending linear low-density polyethylene LLDPE and gas adsorption regulating function filler, and the dehumidifying layer C is formed by blending low-density polyethylene LDPE and moisture absorption function filler. In the PE composite fresh-keeping bag for preventing and controlling cold chain temperature loss, disclosed by the invention, the PE composite fresh-keeping bag comprises: The physical heat insulation layer A is formed by taking Low Density Polyethylene (LDPE) as matrix resin and carrying out melt blending with heat insulation function filler, and is used for reflecting and blocking environmental heat radiation and convection and reducing external heat invasion and internal cold loss. The intelligent gas regulating layer B is formed by taking Linear Low Density Polyethylene (LLDPE) as matrix resin and carrying out melt blending with gas adsorption regulating function filler, and is used for selectively adsorbing excessive carbon dioxide (CO 2) and ethylene (C 2H4) gas and maintaining proper oxygen (O 2) transmission, and dynamically establishing and stabilizing an improved atmosphere (Modified Atmosphere, MA). The dehumidifying la