CN104803078B9

CN104803078B9 - Multifunctional integrated freshness protection package and preparation method thereof

Info

Publication number: CN104803078B9
Application number: CN201510015357.1A
Authority: CN
Inventors: 李东立; 许文才; 廖瑞娟; 石佳子; 付亚波
Original assignee: Beijing Institute of Graphic Communication
Current assignee: Beijing Jianzhen fresh keeping Technology Co.,Ltd.
Priority date: 2015-01-12
Filing date: 2015-01-12
Publication date: 2021-01-15
Anticipated expiration: 2035-01-12
Also published as: CN104803078B; CN104803078A

Abstract

A multifunctional integrated freshness protection package and a preparation method thereof belong to the field of packaging materials. The multifunctional integrated fresh-keeping bag is prepared by taking functional films with functions of ethylene adsorption, ethylene inhibition, antibiosis, high carbon dioxide selective permeation and high water vapor permeation as raw material films and selecting 2-5 from the functional films according to requirements.

Description

Multifunctional integrated freshness protection package and preparation method thereof

Technical Field

The invention relates to a fruit fresh-keeping packaging material, in particular to a design and a preparation method of a multifunctional integrated fresh-keeping bag with high oxygen permeability, water permeability, carbon dioxide permeability, ethylene adsorption, ethylene inhibition and the like, and belongs to the field of packaging materials.

Background

The fresh fruits and vegetables are still subjected to respiration after being picked, the oxidation of nutrient components is generated, heat is released, and metabolites such as moisture, carbon dioxide, ethylene and the like are generated; under the environment of normal temperature and naked storage, the respiration rate of the fruits and vegetables is high, and the fruits and vegetables are easy to age and lose commercial value due to water loss; in a closed environment formed by a common fresh-keeping bag, ethylene, carbon dioxide and water cannot be discharged sufficiently and timely, and the ethylene can accelerate the respiration intensity of the fruits and vegetables and promote the fruits and vegetables to further ripen and age; pathogenic bacteria are easy to breed in a high-humidity environment formed by moisture generated by respiration, so that fruits and vegetables are easy to rot; the high carbon dioxide environment can also cause the rotting of some fruits and vegetables to be aggravated. Therefore, the key to solve the problem of fruit and vegetable preservation is to reduce the respiration rate of fruits and vegetables, keep moisture, prevent pathogenic bacteria from breeding and establish a proper low-oxygen and low-carbon-dioxide atmosphere environment, so that a plurality of fruit and vegetable preservation methods and technologies such as air temperature, air conditioning, dipping and medicament fumigation are developed. There are many types of functional cling films (wrap bags) that have been developed successfully.

Patent ZL 03113758.X introduces a freshness protection package made of non-woven fabrics, has the gas permeability height, does not tie up the characteristics of water smoke; in order to improve the air permeability, a plurality of small holes are arranged on the bag bodies of ZL 201210466049.7 and ZL201310071920.8, and a silicon window is designed on the bag body of ZL200910034625.9 to improve the air permeability; ZL200710061409.4 introduces adding air permeable master batch into polyethylene material to make into film, then processing with smooth surface roller machine, forming small holes with diameter of 1mm-1.5mm on the film, the density of the small holes is 50-100 ten thousand/square meter to increase the air permeability of the fresh-keeping bag; patent 200810059439.6 uses a blended resin modification method to improve the air permeability of the freshness protection package, and adds silica, rubber, etc. into the polyethylene resin.

ZL201210275448.5 introduces a more complicated fresh-keeping bag design, this fresh-keeping bag includes film bag and reservation hole, there is upper label on the reservation hole, is used for controlling opening and closing of the reservation hole; the design of the freshness protection package of ZL200720037273.9 is similar to that of the above patent, the freshness protection package comprises a modified atmosphere film, a base material, an adhesive and a plastic bag with air holes, the modified atmosphere film and the base material are compounded, the adhesive is adhered to the positions of the plastic bag with the air holes, and the content of oxygen, carbon dioxide and other gases in the package bag is adjusted by the modified atmosphere film, so that the respiration intensity of fruits and vegetables is inhibited. In order to increase the bacteriostatic performance, ZL201110334707.2 discloses an electret preservative film, which is prepared by processing and thinning polytetrafluoroethylene or ethylene-tetrafluoroethylene copolymer plastic into a film material and performing electret technical treatment by adopting an electret corona method or a breakdown method; ZL201210588963.9 adding enteromorpha fiber into the paper pulp fiber according to a certain proportion to prepare a fresh-keeping bag containing enteromorpha fiber, and finally smearing 5% of semi-chitosan solution in the fresh-keeping bag to increase the bacteriostatic action of the fresh-keeping bag; ZL200710158884.3 introduces cinnamaldehyde into PE film, which has no bleaching effect on preserved fruit and vegetable.

The fresh-keeping bags have single-layer structures, and in addition, a plurality of fresh-keeping bags have double-layer structures. The freshness protection package introduced in ZL201110368214.0 comprises a ventilating protective layer and a freshness protection layer, wherein an observation window is arranged on the ventilating protective layer, and the freshness protection layer comprises polyethylene resin, sodium alginate and chitosan; the freshness protection package introduced in ZL201220487692.3 comprises an outer bag body and an inner bag body, wherein the inner bag body is arranged in the outer bag body, the bottoms of the outer bag body and the inner bag body are bonded, and a heat insulation layer is arranged between the outer bag body and the inner bag body.

In addition, a plurality of freshness protection bags with 3-layer structures are provided, and ZL200710119153.8 develops an air-conditioning freshness protection bag which is designed into a three-layer structure from inside to outside, wherein the bag body sequentially consists of an air-conditioning freshness protection film, a breathable hydrophilic material layer and a breathable hydrophobic material layer from an outer layer to an inner layer, and a sealing area is arranged at each preset section of the bag body; the top end of the fresh-keeping bag of ZL201320479168.6 is internally provided with a sealing strip, the bag body is sequentially divided into a fresh-keeping layer, a moisture-keeping adsorption layer and a fresh-keeping breathable layer from outside to inside, wherein the moisture-keeping adsorption layer is provided with an ethylene adsorbent, and the surface of the fresh-keeping breathable layer is provided with a breathable small hole.

The bag body made of non-woven fabrics or the design of punching micropores on the bag body can not accurately control the permeability of oxygen and water vapor and has no selectivity on the permeability of carbon dioxide; the oxygen transmission rate can be increased by adding inorganic particles or rubber components into polyethylene or polypropylene resin, but the transmission rate of the polyethylene or polypropylene resin to water vapor is not obviously increased; because the area of the silicon window is small, water vapor and carbon dioxide are difficult to fully permeate through the silicon window, and the processing cost of the freshness protection package is increased due to the design of the silicon window; for the bag body with complex design, the production cost is increased, and large-scale mechanized production is difficult to form; the air permeability of the freshness protection package with the double-layer structure and the three-layer structure is reduced, so that oxygen in the freshness protection package is not supplied enough, and water vapor cannot be discharged in time; the fresh-keeping bag is also a common packaging form by adding the medicine bag in order to increase the bacteriostatic function and the ethylene adsorption function, but the fruits and vegetables can be polluted after the medicine bag is damaged, or the fruits and vegetables are polluted and lose the flavor due to the fact that the concentration of the bactericide released by the medicine bag is too high. The existing fruit and vegetable packaging is always considered, the single film design is difficult to realize the functions of high oxygen permeability, high water permeability, high carbon dioxide selective permeability, bacteriostasis, ethylene adsorption and ethylene inhibition at the same time, and the double-layer or multi-layer composite design can increase the functions of bacteriostasis, ethylene adsorption and ethylene inhibition but loses the high oxygen permeability, high water permeability and high carbon dioxide permeability; the invention adopts the design of the multifunctional integrated freshness protection package to successfully solve the contradictions, so that the freshness protection package has the functions of bacteriostasis, ethylene adsorption and ethylene inhibition, and has the functions of high oxygen permeability, high water permeability and high carbon dioxide selective passage.

Disclosure of Invention

The invention aims to provide a design of a multifunctional integrated freshness protection package and a preparation method thereof. The multifunctional integrated freshness protection package is designed and produced by utilizing the multifunctional films. The multifunctional integrated film coiled material is prepared by taking the raw material films as raw material films, and then the multifunctional integrated freshness protection package is prepared, so that the freshness protection package has all freshness protection functions of the raw material films, and the various freshness protection functions cannot be influenced and weakened mutually.

The multifunctional integrated freshness protection package is formed by splicing at least two of the following 5 materials:

functional film 1(ANTI-MICROBIALS, AM films): the multilayer composite film with the function of intelligently slowly releasing the bactericide can automatically release gas-phase bactericides with different concentrations according to the number of pathogenic bacteria breeding on fruits and vegetables to be preserved, the bactericide cannot generate any residue on the fruits and vegetables, and the type of the bactericide meets the international EC and FDA standards.

Functional film 2(ETHYLENE ABSORBERS, EA films): the invention discloses a fruit fresh-keeping packaging film with ethylene adsorption function, preferably ZL201010522442.4, which is prepared by melting and blending aluminum silicate powder and polyethylene resin in a certain proportion and then blowing the film.

Functional film 3(1-MCP releasing, MR films): a composite film having a 1-MCP release function. 1-methylcyclopropene (1-MCP) gas can inhibit the fruits and vegetables from generating ethylene, and 1-MCP preparations in the market are prepared by adsorbing 1-MCP on a cyclodextrin carrier, dispersing the cyclodextrin in water, releasing 1-MCP gas with a certain concentration, and fumigating and preserving the fruits and vegetables; since the release concentration and release period are difficult to control accurately, the application is limited; the invention preferably adopts the composite film with the 1-MCP release function disclosed in CN102862361A, the film automatically slowly releases the gas phase 1-MCP after encountering water vapor generated by respiration of fruits and vegetables, when the respiration intensity of the fruits and vegetables is high, the relative humidity in the fresh-keeping bag is high, the higher the concentration of the 1-MCP released by the film is, the higher the inhibition effect on the respiration of the fruits and vegetables is, and the automatic slow-down regulation on the metabolism of the fruits and vegetables is realized.

Functional thin film 4(High CO)₂TR and OTR film, HCO films): a film having high oxygen permeability and high carbon dioxide selective permeability, preferably one having high oxygen permeability and high carbon dioxide selective permeability as disclosed in ZL201210363822.7Film having an Oxygen Transmission Rate (OTR) of 10⁵ml/m²Day. atm or more, and preferably carbon dioxide (CO)₂TR) is 6 times of OTR, can timely eliminate carbon dioxide generated by respiration of fruits and vegetables, and prevents the fruits and vegetables from aging caused by carbon dioxide enrichment.

Functional film 5(High MVTR film, HM films): ZL201010532453.0 discloses a diatomite modified polyethylene film, wherein porous and hydrophilic diatomite has higher permeability to water vapor, and the Water Vapor Transmission Rate (WVTR) of the modified film reaches 100-²Day, can in time get rid of the steam that produces in the wrapping bag (freshness protection package), reduce the relative humidity in the freshness protection package, restrain bacterial growing.

Wherein OTR, CO of the functional film 1(AM film)₂TR value is 2000-5000ml/m²Between day.atm, relative to HCO films, AM films contribute negligible to oxygen and carbon dioxide transmission; WVTR of AM films is less than 10g/m²Day, relative to HM films, AM films can also neglect the contribution to water vapor permeability; that is, in the integrated design, AM films only contribute to the sterilization performance, and the contribution to the gas transmission performance is negligible.

The functional film 1 of the present invention is preferably any one of the films disclosed in application nos. 200910086775.4 and 201210365158. X.

Wherein application number 200910086775.4 includes: (a) the inner layer is a controlled release layer and is composed of polyethylene vinyl acetate copolymer-low density polyethylene blended resin with a certain proportion; (b) the middle layer is a generation layer of bactericide and consists of a binder and a bactericide precursor; (c) an outer layer, being a barrier layer and/or a printed layer of sulphur dioxide, a non-polar film consisting of a material selected from the group consisting of: low density polyethylene, or a blend modified resin film of low density polyethylene and linear low density polyethylene, high density polyethylene, medium density polyethylene, or biaxially oriented polypropylene; optionally, (d) a first additional layer between the inner portion of the outer layer as a print layer and the outer portion of the middle layer as a biocide-generating layer, the first additional layer selected from the group consisting of nylon film, polyethylene terephthalate film.

The application number 201210365158.X comprises three layers, wherein the outer layer is a high-barrier layer; the middle layer is a binder layer and is a dry adhesive film; the inner layer is a food contact layer; the outer layer is high oxygen-barrier KBOPP, VMCPP, VMPET, SiOx/PET, Al₂O₃A barrier film consisting of one or more PET; the middle layer is one or a mixture of more of organic acid or organic acid sodium salt as an active antibacterial component, the active antibacterial component is added into the polyurethane or acrylate binder, the mass percentage of the active antibacterial component in the middle layer is 2-15%, and the amount of the binder dry glue is 3-7 g/sq m; the inner layer is made of EVA modified LDPE modified resin, and the EVA accounts for 5-50% of the total mass of the inner layer; the organic acid is one or more of citric acid, sorbic acid, malic acid, tartaric acid and benzoic acid.

OTR, CO of functional film 2(EA film)₂TR value is also 2000-5000ml/m²Atm and WVTR lower than 10g/m²Day, EA films only contributes to ethylene adsorption performance and negligible contribution to gas transmission performance in the integrated design.

The functional film 2(EA film) of the invention is preferably a fruit fresh-keeping green packaging material with the function of adsorbing ethylene disclosed by ZL201010522442.4, and comprises the following components: 100-90 parts by mass of polyethylene or polypropylene resin and 0.5-10 parts by mass of an aluminum silicate molecular sieve, wherein the particle size of the aluminum silicate molecular sieve is 5-100 micrometers, and the silicon-aluminum ratio is 5-100; the preparation method comprises the following steps: adding pseudo-boehmite into water at room temperature, and stirring and mixing uniformly; then adding a template agent and silica sol until gel is formed; putting the gel into a stainless steel autoclave, heating to 200-250 ℃ in a sealed manner, and crystallizing for 48 hours at a constant temperature under the self pressure; after crystallization is completed, washing with deionized water and drying; finally, roasting for 4-6 hours at 500-700 ℃ to completely remove the template agent, and crushing to 5-100 micron particles to obtain raw powder of the molecular sieve, wherein the Si/Al molar ratio in the molecular sieve is 5-100; after 100-90 parts of polyethylene or polypropylene resin and 0.5-10 parts of molecular sieve are uniformly mixed, the mixture is melted and blended on a double-screw extruder, and then the mixture is blown into a film.

The case of the functional film 3(MR film) is also similar to EA films and AM films, and in the integrated design, the MR films release only 1-MCP, contributing to the ethylene suppression function, while the contribution to the gas permeability is negligible.

The functional film 3(MR film) of the invention is preferably CN102862361A, which discloses a fruit and vegetable fresh-keeping packaging material capable of releasing 1-methylcyclopropene, the packaging material is a multilayer composite film, and comprises a barrier layer for 1-MCP gas, a middle layer adhesive or a 1-MCP release layer on the outermost layer, and a food contact layer or a controlled release layer for 1-MCP on the innermost layer; the outer layer is a 1-MCP barrier layer, and one or more of Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE) and High Density Polyethylene (HDPE) are taken as main bodies, or a polypropylene film BOPP (biaxially oriented polypropylene) and a CPP (cast polypropylene) are taken as main bodies, or polyethylene and polypropylene resin are taken as main bodies, and a film and the like with EVA (ethylene-vinyl acetate copolymer) as a modifier added in the main bodies are taken as outer layers; the EVA modified PE-rubber blend is used as an inner layer; 1-methylcyclopropene (1-MCP) is used as an active ingredient, a dry glue layer obtained by adding 1-MCP/cyclodextrin into a common polyurethane or acrylate binder is used as a middle layer, the 1-MCP/cyclodextrin is that 1-MCP is adsorbed on a cyclodextrin carrier, the mass content of the 1-MCP is 3-5%, the polarity of the outer layer is higher than that of the inner layer, and the barrier property of the outer layer is higher than that of the inner layer.

OTR, CO of functional thin film 4(HCO thin film)₂TR value is 10⁵-10⁶ml/m²Between day and atm, the main function is to provide oxygen for the freshness protection package and discharge carbon dioxide in the freshness protection package; HCO films having a WVTR of less than 20g/m²Day, the HCO films contribute negligible to the water vapor transmission performance in the integrated design, considering only the contribution to oxygen and carbon dioxide transmission.

The functional film 4(HCO film) is preferably a film material disclosed in ZL201210363822.7, has a single-layer structure, and is a film formed by melt blending one or more of Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE) and High Density Polyethylene (HDPE) as matrix resin with an amorphous polymer and then blow molding, wherein the amorphous polymer is one or more of styrene-butadiene block copolymer (SBS), Ethylene Propylene Diene Monomer (EPDM), ethylene-octene copolymer (POE), Polybutadiene (PB), Natural Rubber (NR) and ethylene-vinyl acetate (EVA), and the total proportion of the amorphous polymer in the system is 25-30%.

OTR, CO of functional film 5(HM film)₂TR value is 10⁴ml/m²About day. atm, which is relatively small in contribution to the permeability of oxygen and carbon dioxide compared to HCO films, and can be generally ignored; WVTR of HM films is 200g/m²Between day, in the integrated design, HM films only considers the contribution to water vapor permeability, whereas the contribution to carbon dioxide and oxygen permeability is negligible.

The functional film 5(HM film) is preferably a fruit fresh-keeping packaging material with high air permeability disclosed in ZL201010532453.0, the raw material of the material comprises modified diatomite and LDPE, the modified diatomite is diatomite with a layer of polyvinyl acetate, polyacrylic resin or copolymer thereof coated on the surface; the method for modifying the diatomite comprises the following steps: dispersing diatomite in water, adding vinyl acetate or/and acrylic monomers, heating to 40-60 ℃, adding hydrogen peroxide with the concentration of 30%, adding a ferrous chloride aqueous solution with the mass concentration of 10%, reacting for 4-10 hours, drying, and crushing to obtain modified diatomite; wherein 100 g of diatomite is correspondingly dispersed in 500ml of water, then 5-200 ml of monomer is correspondingly added, the adding amount of hydrogen peroxide is correspondingly 0.5-5 ml, and the adding amount of ferrous chloride aqueous solution is correspondingly 0.2-2 ml; the acrylic monomer is methyl acrylate monomer or methyl methacrylate monomer.

Selecting the quantity and variety of functions to be integrated according to the variety of the fruits and vegetables to be preserved; and calculating the area of each functional film according to the weight of the fruits and vegetables and the respiration rate at the preservation temperature.

In general, the HCO film of the functional film 4 and the HM film of the functional film 5 are necessary for designing each freshness protection package, the HCO film provides proper oxygen concentration and carbon dioxide concentration for the freshness protection package, and the HM film timely removes moisture in the freshness protection package, prevents moisture condensation at the inner side of the freshness protection package, and reduces the probability of breeding pathogenic bacteria; if the fruit is in the breath jump type, the EA film or the MR film is a functional film which is necessary to be added, so that ethylene generated by the respiration of the fruit can be absorbed in time, and the breath jump is delayed and dragged; if the fruits and vegetables are easy to breed fungi or other pathogenic bacteria, an AM film with the bacteriostatic function is added in the design of the fresh-keeping bag.

If W kilograms of fruit needs a fresh-keeping bag with the shape height of H meters and the width of D meters for fresh-keeping, the fresh-keeping temperature is T, and at the temperature, the respiration rate of the fruit is R mlCO₂/(kg.hr) or consumption of R ml O₂(kg.hr), the respiration rate of the fruit is current or known at a certain temperature; after the gas concentration in the fresh-keeping bag reaches balance, the balance volume percentage concentration of each component is respectively C_O2、C_CO2The relative humidity is RH, the volume percentage concentration of oxygen in the external air is 20%, the concentration of carbon dioxide is zero, and the relative humidity of the external air is RH₀Then the following relationship exists:

oxidation reaction of glucose:

C₆H₁₂O₆+6O₂＝6CO₂+6H₂o + Heat (1)

From the formula (1), it can be deduced that if the freshness protection package is filled with W kg, the respiration rate is R mlCO₂/(kg. hr) (or R mlO₂/(kg. hr)) the water vapor mass (g) per hour due to respiration is:

H₂O(g/hr)＝W×R×18/(22.4×1000) (2)

the gas in the freshness protection package and the gas in the external environment have the following balance:

oxygen balance: w × R ═ OTR_HCO×H×di_HCO×(20％-C_O2)×24hr (3)

Carbon dioxide balance: w × R ═ CO₂TR_HCO×H×di_HCO×(C_CO2-0)×24hr

(4)

Equilibrium of water vapor:

W×R×18/(22.4×1000)×24hr＝WVTR×H×di_HM×(RH-RH₀)

(5)

the weight of the W-fruit is kg; r-respiration rate of fruit, ml/(kg-hr); OTR_HCOOxygen transmission of functional film 4(HCO film), ml/m²·24hr.atm；CO₂TR_HCOCarbon dioxide gas permeability of functional film 4(HCO film), ml/m²·day·atm；C_O2-the percentage by volume of oxygen in the bag after the gas has equilibrated,%; c_CO2-the percentage by volume of carbon dioxide in the freshness protection package after the gas has equilibrated in%; h-bag height, m; di_HCOThe width of the functional film 4 in the bag, the greater of the two, m, according to equations (3) and (4); di_HMWidth of the functional film 5 in the bag, m; water vapor transmission rate, g/m, of WVTR-functional film 5²24hr 100% RH; after the RH-gas reaches the balance, the relative humidity in the freshness protection package is calculated; RH (relative humidity)₀-relative humidity of the ambient air, in%; c_CO2、C_O2Generally, the optimal atmosphere composition of the preserved fruits and vegetables is obtained by consulting documents or self-testing according to a preservation test. WVTR is the water vapor transmission rate of HM.

According to the formulas (3) and (4), it can be found that when the gas components in the freshness protection package are balanced and the optimal oxygen or carbon dioxide concentration is reached, the HCO film with the height of H is required to be prepared into the multifunctional integrated freshness protection package and the width of the HCO film is di_HCOGenerally, a larger value is taken; according to the formula (5), when the inner side of the freshness protection package is not condensed (RH is less than 100%, the relative humidity in the general freshness protection package is 95% -100%), the relative humidity of the outside air is a change value, the average relative humidity RH in the season and the day is generally taken, and the required HM film width di_HM。

The total surface area of the freshness protection package is DXH square meter of formula (3), di is obtained according to formulae (3) and (4)_HCO(i.e., the area of HCO film), the area of HM film was obtained according to the formula (5), and the remaining area of the wrap (DxH-H (di)) was determined after the areas of the two films were used_HCO+di_HM) The areas of the ethylene inhibition, ethylene adsorption and bacteriostasis films can be determined according to the concentration of the ethylene released by fruits and vegetables and the degree of easy breeding of pathogenic bacteria.

If the fruits and vegetables are in non-respiratory transition type or do not generate ethylene basically under the respiratory action, the three-function integrated design can be used, the ethylene adsorption function is not used, and only three functions of HCO, HM and AM are used; if the concentration of ethylene generated by respiration of fruits and vegetables is very high, a five-function integrated freshness protection package design is adopted, namely, an MR film (ethylene inhibition) functional film is additionally used on the basis of the four-function freshness protection package design.

If the fruits and vegetables are not suitable for breeding bacteria and the respiration does not generate ethylene, a two-function integrated design is adopted, and only HCO and HM films are adopted; in this case, if the size of the freshness protection package is large and the sum of the areas of the desired HCO film and HM film is found to be smaller than H × D after calculation, the HM film area can be increased.

If it is found that the total area of the multifunctional film is greater than H × D, HCO film and HM film having higher air permeability are prepared, and the air permeability of AM and EA film is increased if necessary.

Bag making method

Several rolls of functional film as required are slit to the desired width (di) and then heat sealed or adhesively bonded to form the corresponding rolls (shown in fig. 2), which are then heat sealed or bonded on an automated bag machine to form a crisper pillow-type freshness protection package, the height of the package being H.

Preservation application

The multifunctional integrated fresh-keeping bag is particularly suitable for keeping fruits and vegetables which have high respiratory strength and generate more ethylene by respiration, particularly suitable for keeping the fruits and vegetables in respiratory transition type, and particularly suitable for keeping the fruits and vegetables at normal temperature. The fruit and vegetable without mechanical damage and pathogenic bacteria infection is selected, directly placed into the multifunctional integrated freshness protection package, and the bag opening is tightened, the freshness protection package is preferably placed on the lower breathable partition plate, so that the films at all parts of the freshness protection package can play a role in ventilation, and the films at the lower side of the freshness protection package in contact with the tray can normally play a role.

The medlar has pulpy pulp, thin skin and easy damage, and the commodity of the medlar is generally in a dry medlar form; the rotten fruit rate of fresh medlar just picked can reach more than 10% on the second day, 30% on the third day and about 50% on the fourth day. The fresh-keeping problem of the fresh medlar has not been solved all the time, so the fresh medlar can only be sold in the production place. The fresh-keeping problem of the fresh medlar is successfully solved by utilizing the multifunctional integrated fresh-keeping bag.

Drawings

Fig. 1 is a design schematic diagram of a multifunctional integrated freshness protection package.

Fig. 2 is a schematic diagram of a multifunctional integrated preservative film coiled material.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples.

Example 1

A piece of 0.3m 0.25m HM film and the same size AM film are used as an upper piece and a lower piece to prepare a two-function integrated fresh-keeping bag, 80 (about 40 g) fresh Chinese wolfberry grains are filled in the bag, the bag is sealed, the two-function integrated fresh-keeping bag is placed on a ventilating clapboard, and the two-function integrated fresh-keeping bag is observed at the room temperature of 25 ℃.

Comparative example 1:

80 fresh Chinese wolfberry fruits with the same mass are placed in a polypropylene (PP) plastic box, the outer dimension of the plastic box is 10cm multiplied by 8cm, holes are punched on the cover, the side face and the lower side, the hole diameter is 5mm, and 20 holes are formed in total, so that the rotting condition is observed. And detecting the headspace atmosphere in the two-function integrated fresh-keeping bag after four days and counting the rotten fruit rate.

Observing the two-function integrated freshness protection package, no water mist appears on the inner side of the freshness protection package within 1-4 days, the rotten fruit rate is only 15% after 4 days, and analysis shows that the oxygen concentration in the freshness protection package is stabilized at 12.5% and the carbon dioxide concentration is 5.8%, which shows that the HM/AM two-function integrated freshness protection package can obviously reduce the breath of fresh medlar and delay the maturation, aging and decay of medlar, and compared with the rotten fruit rate of a control group of 45%, the rotten fruit rate is reduced to 1/3.

Example 2

Sealing and splicing an AM film of 0.1m multiplied by 0.25m and an HCO film of 0.2m multiplied by 0.25m into a size of 0.3m multiplied by 0.25m to prepare an AM/HCO integrated film, taking the AM/HCO integrated film and another HM film of 0.3m multiplied by 0.25m as an upper sheet and a lower sheet to prepare a three-function integrated freshness protection package AM/HCO/HM, filling 200 (about 100 g) fresh Chinese wolfberry grains, sealing, placing the three-function integrated freshness protection package on a partition board with a ventilating lower end, and observing at the room temperature of 25 ℃;

comparative example 2

200 fresh medlar with the same mass are put in a polypropylene (PP) plastic box, the appearance size and the punching condition of the plastic box are the same as those of the comparative example 1, and the rotting condition of the medlar is observed. And detecting the headspace atmosphere in the three-function integrated freshness protection package after four days and counting the rotten fruit rate.

Observing the AM/HCO/HM three-function integrated freshness protection package, wherein water mist does not appear on the inner side of the freshness protection package within 1-4 days, the rotten fruit rate is only 10% after 4 days, and the analysis shows that the oxygen concentration in the freshness protection package is stabilized at 15.5% and the carbon dioxide concentration is 0.4%, which shows that the AM/HCO/HM three-function freshness protection package can obviously reduce the breath of fresh medlar, delay the maturation and aging of medlar, timely permeate out the carbon dioxide generated by the breath of medlar and prevent the medlar from being damaged by overhigh carbon dioxide; compared with the control group with the rotten fruit rate of 50%, the rotten fruit rate of the three-function integrated freshness protection package is reduced to 1/5 of the control group.

Example 3

Sealing 1 piece of 0.15m × 0.25m AM thin film and 1 piece of 0.15m × 0.25m HCO thin film into one piece of 0.3m × 0.25m (AM/HCO thin film); sealing 1 piece of 0.15m × 0.25m HM film and 1 piece of 0.15m × 0.25m MR film to one piece of 0.3m × 0.25m film (MR/HM film); taking 1 AM/HCO film and 1 MR/HM film prepared above as an upper piece and a lower piece, preparing a four-function integrated freshness protection package AM/HCO/HM/MR, filling 200 fresh Chinese wolfberry fruits, sealing, placing the four-function integrated freshness protection package on a partition board with a breathable lower end, and observing at 25 ℃ at room temperature;

comparative example 3

The AM/HCO/HM/MR four-function integrated freshness protection package is observed, no water mist appears at the inner side of the freshness protection package within 1-4 days, the rotten fruit rate is only 5% after 4 days, the oxygen concentration in the freshness protection package is stable at 13.5% through analysis, and the carbon dioxide concentration is 1.4%, so that the AM/HCO/HM/MR four-function integrated freshness protection package can obviously reduce the breath of fresh medlar, delay the maturity and aging of medlar, can timely permeate out the carbon dioxide generated by the breath of medlar, and can obviously inhibit the medlar from generating ethylene in addition to the function of bacteriostasis, compared with the comparison group with the rotten fruit rate of 50%, the rotten fruit rate of the four-function and finished freshness protection package is reduced to 1/10.

The multifunctional integrated freshness protection package ingeniously solves the multifunctional integration problem, avoids the problems that the design of the existing freshness protection package is too complex, the air permeability is influenced by multi-layer compounding and the like, can integrate more functions as required, and needs a functional film with larger air permeability as a raw material film. It should be understood by those skilled in the art that the above-described preferred embodiments are merely illustrative of the present invention and are not to be construed as limiting the present invention. Numerous modifications, combinations, sub-combinations and variations are possible as desired, and all modifications, combinations, sub-combinations, variations and equivalents are intended to fall within the scope of the appended claims.

Claims

1. The multifunctional integrated freshness protection package is characterized in that the multifunctional integrated freshness protection package is formed by splicing at least two of the following 5 materials:

functional film 1, AM film: a multilayer composite film with an intelligent slow-release bactericide function;

functional film 2, EA film: a fruit fresh-keeping packaging film with the function of adsorbing ethylene;

functional film 3, MR film: a composite film having a 1-MCP release function;

functional film 4, which is a HCO film: a film having a high oxygen permeability and a high carbon dioxide selective permeability;

the functional film 5 is an HM film, a diatomite modified polyethylene film, and the water vapor transmission rate WVTR of the modified film reaches 100-².day；

Wherein OTR, CO of AM thin film₂TR value is 2000-5000ml/m²Between day.atm, AM film contributes negligibly to oxygen and carbon dioxide transmission, relative to HCO film; WVTR of AM film is less than 10g/m²Day, AM film vs. HM film vs. waterThe contribution of vapor permeability may also be negligible; that is, in the integrated design, the AM film contributes only to the sterilization performance, and contributes only negligibly to the gas permeability.

2. The multifunctional integrated freshness protection package according to claim 1, wherein the functional film 1 is any one of the following films;

a film, comprising: (a) the inner layer is a controlled release layer and is composed of polyethylene vinyl acetate copolymer-low density polyethylene blended resin with a certain proportion; (b) the middle layer is a generation layer of bactericide and consists of a binder and a bactericide precursor; (c) an outer layer, being a barrier layer and/or a printed layer of sulphur dioxide, a non-polar film consisting of a material selected from the group consisting of: low density polyethylene, or a blend modified resin film of low density polyethylene and linear low density polyethylene, high density polyethylene, medium density polyethylene, or biaxially oriented polypropylene; (d) a first additional layer between the interior of the outer layer as a print layer and the exterior of the middle layer as a biocide-generating layer, the first additional layer selected from a nylon film or a polyethylene terephthalate film;

or a film: comprises three layers, wherein the outer layer is a high barrier layer; the middle layer is a binder layer and is a dry adhesive film; the inner layer is a food contact layer; the outer layer is high oxygen-barrier KBOPP, VMCPP, VMPET, SiOx/PET, Al₂O₃A barrier film consisting of one or more PET; the middle layer is one or a mixture of more of organic acid or organic acid sodium salt as an active antibacterial component, the active antibacterial component is added into the polyurethane or acrylate binder, the mass percentage of the active antibacterial component in the middle layer is 2-15%, and the amount of the binder dry glue is 3-7 g/sq m; the inner layer is made of EVA modified LDPE modified resin, and the EVA accounts for 5-50% of the total mass of the inner layer; the organic acid is one or more of citric acid, sorbic acid, malic acid, tartaric acid and benzoic acid.

3. The multifunctional integrated freshness protection package according to claim 1, wherein O of the functional film 2TR、CO₂TR value is 2000-5000ml/m²Atm and WVTR lower than 10g/m²Day, the EA film contributes only to the ethylene adsorption performance and contributes negligibly to the gas transmission performance in the integrated design.

4. The multifunctional integrated freshness protection package according to claim 1, wherein the functional film 3 is a fruit and vegetable freshness protection packaging material capable of releasing 1-methylcyclopropene, the packaging material is a multilayer composite film comprising an outermost layer which is a barrier layer against 1-MCP gas, an intermediate layer adhesive or a 1-MCP release layer, and an innermost layer which is a food contact layer or a controlled release layer of 1-MCP; the outer layer is a 1-MCP barrier layer, and the outer layer is a film which takes one or more of Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE) as a main body, or takes a polypropylene film BOPP (biaxially oriented polypropylene) and a CPP (cast polypropylene) as main bodies, or takes polyethylene and polypropylene resin as main bodies and is added with EVA (ethylene-vinyl acetate copolymer) as a modifier in the main bodies; the EVA modified PE-rubber blend is used as an inner layer; 1-methylcyclopropene (1-MCP) is used as an active ingredient, a dry glue layer obtained by adding 1-MCP/cyclodextrin into a common polyurethane or acrylate binder is used as a middle layer, the 1-MCP/cyclodextrin is that 1-MCP is adsorbed on a cyclodextrin carrier, the mass content of the 1-MCP is 3-5%, the polarity of the outer layer is higher than that of the inner layer, and the barrier property of the outer layer is higher than that of the inner layer.

5. The multifunctional integrated freshness protection package according to claim 1, wherein the OTR, CO of said functional film 4₂TR value is 10⁵-10⁶ml/m²Atm and a HCO film having a WVTR of less than 20g/m².day。

6. The multifunctional integrated fresh-keeping bag according to claim 1, wherein the functional film 4 has a single layer structure, and is a film formed by melt blending one or more of Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE) and High Density Polyethylene (HDPE) as a matrix resin with an amorphous polymer and then blow molding, the amorphous polymer is one or more of styrene-butadiene block copolymer (SBS), Ethylene Propylene Diene Monomer (EPDM), ethylene-octene copolymer (POE), Polybutadiene (PB), Natural Rubber (NR) and ethylene-vinyl acetate (EVA), and the total proportion of the amorphous polymer in the system is 25-30%.

7. The multifunctional integrated freshness protection package according to claim 1, wherein the functional film 5 is a fruit freshness protection package material with high air permeability, the raw materials of the material comprise modified diatomite and LDPE, and the modified diatomite is diatomite with a layer of polyvinyl acetate, polyacrylic resin or copolymer of polyvinyl acetate and polyacrylic acid wrapped on the surface; the method for modifying the diatomite comprises the following steps: dispersing diatomite in water, adding vinyl acetate or/and acrylic monomers, heating to 40-60 ℃, adding hydrogen peroxide with the concentration of 30%, adding a ferrous chloride aqueous solution with the mass concentration of 10%, reacting for 4-10 hours, drying, and crushing to obtain modified diatomite; wherein 100 g of diatomite is correspondingly dispersed in 500ml of water, then 5-200 ml of monomer is correspondingly added, the adding amount of hydrogen peroxide is correspondingly 0.5-5 ml, and the adding amount of ferrous chloride aqueous solution is correspondingly 0.2-2 ml; the acrylic monomer is methyl acrylate monomer or methyl methacrylate monomer.

8. The multifunctional integrated fresh-keeping bag according to claim 1, wherein at least the HCO film of the functional film 4 and the HM film of the functional film 5 are included.

9. The multifunctional integrated freshness protection package according to claim 8, wherein if W kg of fruit needs a freshness protection package with an outer shape height of H m and a width of D m for freshness protection, the freshness protection temperature is T, at which the respiration rate of fruit is R ml CO production₂/(kg.hr) or consumption of R ml O₂(kg.hr), the respiration rate of the fruit is current or known at a certain temperature; after the gas concentration in the fresh-keeping bag reaches balance, the balance volume percentage concentration of each component is respectively C_O2、C_CO2Relative humidity ofRH, the volume percentage concentration of oxygen in the outside air is 20%, the concentration of carbon dioxide is zero, and the relative humidity of the outside air is RH₀Then the following relationship exists:

oxidation reaction of glucose:

C₆H₁₂O₆+6O₂＝6CO₂+6H₂o + Heat (1)

From the formula (1), it can be deduced that if the freshness protection package is filled with W kg, the respiration rate is R mlCO₂/(kg. hr) or R mlO₂The weight g of water vapor generated per hour due to respiration of fruits and vegetables (kg hr) is as follows:

H₂O(g/hr)＝W×R×18/(22.4×1000) (2)

oxygen balance: w × R ═ OTR_HCO×H×di_HCO×(20％-C_O2)×24hr (3)

Carbon dioxide balance: w × R ═ CO₂TR_HCO×H×di_HCO×(C_CO2-0)×24hr (4)

Equilibrium of water vapor:

W×R×18/(22.4×1000)×24hr＝WVTR×H×di_HM×(RH-RH₀) (5)

the weight of the W-fruit is kg; r-respiration rate of fruit, ml/(kg-hr); OTR_HCOOxygen transmission of functional film 4, i.e. HCO film, ml/m²·24hr.atm；CO₂TR_HCOCarbon dioxide gas permeability of the functional film 4, ml/m²·day·atm；C_O2-the percentage by volume of oxygen in the bag after the gas has equilibrated,%; c_CO2-the percentage by volume of carbon dioxide in the freshness protection package after the gas has equilibrated in%; h-bag height, m; di_HCOThe width of the functional film 4 in the bag, the greater of the two, m, according to equations (3) and (4); di_HMWidth of the functional film 5 in the bag, m; water vapor transmission rate, g/m, of WVTR-functional film 5²24hr 100% RH; after the RH-gas reaches the equilibrium, the relative humidity in the freshness protection package is％；RH₀-relative humidity of the ambient air, in%; c_CO2、C_O2Selecting the optimal atmosphere composition of the preserved fruits and vegetables; WVTR is the water vapor transmission rate of HM.

10. The method for preparing a multifunctional integrated freshness protection package according to claim 1, wherein the multifunctional integrated film roll is prepared first, and then the multifunctional integrated freshness protection package is prepared.