CN107814967A - Anti-mildew fresh-keeping film and preparation method thereof - Google Patents

Abstract

The invention relates to a mildew-proof and fresh-keeping film and a preparation method thereof. The mildew-proof and fresh-keeping film comprises a base film, a silicone rubber coating and a mildew-proof and fresh-keeping coating; the base film is provided with vent holes, and the silicone rubber coating and The anti-mildew and fresh-keeping coatings are respectively formed on both sides of the base film, and the raw materials of the silicone rubber coating include the following components by weight percentage: 52% to 63% of silicone rubber, 20% to 25% of polyurethane %, polyacrylic acid γ-methacryloxypropyl trimethoxysilane 12% to 18%, silicon carbide 5% to 10%, titanium dioxide 3% to 8%, and monovalent silver source 1% to 3%. When the anti-mold plastic wrap is used for packaging materials, when packaging fruits and vegetables and other products, the fruits and vegetables themselves do not need to undergo any anti-corrosion, anti-mold, sterilization and fresh-keeping treatment, only need to put the clean fruits and vegetables in the anti-mold plastic wrap and other packaging products, through the packaging product itself The anti-mold and sterilizing function and the breathable function of ethylene can achieve the anti-mold and fresh-keeping effect on the placed objects in the packaged products, effectively prolonging the freshness of fruits and vegetables during transportation and storage, and the market application prospect is broad.

Description

Anti-mold plastic wrap and preparation method thereof

technical field

The invention relates to the field of fresh-keeping technology, in particular to a mildew-proof fresh-keeping film and a preparation method thereof.

Background technique

The storage conditions for items with a short storage period such as fruits and vegetables are relatively harsh, otherwise they will become moldy due to the proliferation of microorganisms, making them no longer fresh and losing their original value. At present, the fresh-keeping method in the industry is generally simply wrapped with plastic wrap to isolate external oxygen and moisture, so as to achieve the purpose of fresh-keeping. But the fresh-keeping effect of this fresh-keeping method is not good, especially when it is used for fresh-keeping of fruits and vegetables, the respiration of the fruits and vegetables itself produces condensation on the inner wall of the plastic wrap, which easily leads to bacterial growth and mildew, and accelerates the ripening and rot of fruits and vegetables.

Contents of the invention

Based on this, it is necessary to provide a mildew-resistant fresh-keeping film with better fresh-keeping effect and a preparation method thereof.

A mildew-proof fresh-keeping film, comprising a base film, a silicone rubber coating and a mildew-proof fresh-keeping coating; the base film is provided with air holes, and the silicone rubber coating and the mildew-proof fresh-keeping coating are formed on On both sides of the base film, the raw materials of the silicone rubber coating include the following components by weight percentage: 52% to 63% of silicone rubber, 20% to 25% of polyurethane, polyacrylic acid γ-methacryloxy 12%-18% of propyltrimethoxysilane, 5%-10% of silicon carbide, 3%-8% of titanium dioxide and 1%-3% of monovalent silver source.

In one embodiment, the silicone rubber is selected from one or more of methyl silicone rubber, methyl vinyl silicone rubber, methylphenyl vinyl silicone rubber and fluorosilicone rubber.

In one embodiment, the silicone rubber is composed of the following components in weight percentage: 70%-80% methyl vinyl silicone rubber and 20%-30% fluorosilicone rubber.

In one embodiment, the monovalent silver source is silver nitrate.

In one of the embodiments, the air holes have a diameter of 0.5-0.7 nm.

In one embodiment, the distribution density of the air holes is 20-40 holes/cm ² .

In one embodiment, the raw materials of the anti-mold and fresh-keeping coating include the following components by weight percentage: 20%-50% of the main resin, 20%-70% of the solvent, 0.65%-25.5% of the anti-mold agent, 0.3% to 4% of water-retaining materials and 0.2% to 2% of additives.

In one of the embodiments, the host resin is selected from at least one of polyurethane, acrylic copolymer, ethylene-vinyl acetate copolymer, polyvinyl acetate copolymer and polyvinyl alcohol with a degree of hydrolysis greater than 85%. The water-retaining material is selected from at least one of hydroxyacrylate, glycerol, porous inorganic materials and superabsorbent resins

In one of the embodiments, the mass ratio of the antifungal agent to the water-retaining material is 4-6:1.

The preparation method of above-mentioned anti-mildew preservative film, comprises the following steps:

Blending the raw materials of the silicone rubber coating with n-hexane to obtain a silicone rubber coating;

uniformly mixing the main resin and the solvent to obtain a mixed liquid; sequentially adding the water-retaining material, the auxiliary agent and the anti-fungal agent to the mixed liquid and mixing uniformly to obtain an anti-mold fresh-keeping coating;

One surface of the base film is coated with a silicone rubber coating and heat-treated to form a silicone rubber coating, and the anti-mold fresh-keeping coating is coated on a surface of the base film away from the silicone rubber coating and heat-treated The mildew-proof and fresh-keeping coating is formed into the mildew-proof and fresh-keeping coating to obtain the mildew-proof and fresh-keeping film.

Ethylene is a plant hormone that will slowly accumulate and release during the development of fruits and vegetables and other horticultural plants. When the released ethylene reaches a certain amount around the fruits and vegetables, it will accelerate the ripening and decay of fruits and vegetables and reduce the commodity value of fruits and vegetables. In the storage environment of fruits and vegetables, ethylene will also change the effect of carbon dioxide on fruits and vegetables and cause metabolic disorders of fruits and vegetables. Therefore, the traditional plastic wrap cannot effectively reduce the ethylene concentration around the fruits and vegetables, and in order to ensure effective isolation from the external environment, the air permeability is often very low, resulting in a gradual increase in the ethylene concentration, which accelerates the rotting speed of fruits and vegetables, affects the preservation effect, and shortens the Keep fresh for a long time. The mildew-proof and fresh-keeping film of the present invention is close to the surface of the mildew-proof and fresh-keeping coating when packing fruits and vegetables, can inhibit the growth of mold in the package, and is not easy to produce mildew when the fruits and vegetables are not pre-treated. The ethylene released by the fruits and vegetables in the anti-mold plastic wrap can be discharged from the air holes of the base film, and the air permeability of the side of the base film with the anti-mold and fresh-keeping coating is greater than that of the side of the base film with the silicone rubber coating, even The prepared anti-mildew fresh-keeping film has good one-way air permeability. Silicone rubber is a high-molecular elastic material with excellent comprehensive properties. The molecular chain is composed of silicon atoms and oxygen atoms alternately, and has good air permeability. Oxysilane is blended and modified, and silicon carbide inorganic powder is added to form an organic-inorganic hybrid membrane to further improve the gas separation performance. At the same time, titanium dioxide can degrade ethylene under photocatalysis, causing a difference in ethylene concentration on both sides of the base film, which provides the power for the diffusion of ethylene to the silicone rubber coating, and promotes the continuous outward diffusion of ethylene inside the base film, significantly improving the ethylene concentration. The pass rate reduces the pass rate of other gases. On the one hand, monovalent silver ions can form π-complexes with ethylene to assist in the absorption of ethylene, and promote the outward diffusion of ethylene inside the basement film; It improves the photocatalytic efficiency, removes ethylene around fruits and vegetables more efficiently, keeps the ethylene concentration at a very low level, and does not affect the respiration of fruits and vegetables, thus improving the freshness preservation effect and prolonging the freshness preservation period.

Furthermore, the water-retaining material in the anti-mold plastic wrap has strong water absorption, and absorbs the water vapor before it reaches the vent holes of the base film, and slowly releases water vapor into the anti-mold plastic wrap after reaching a certain concentration. , and then effectively inhibit the water loss of fruits and vegetables, and the presence of antifungal agents can prevent mildew in fruits and vegetables. In this way, the inside of the anti-mold plastic wrap is in a state of low ethylene concentration and water vapor balance, which further effectively avoids the condensation on the inner wall of the anti-mold plastic wrap, which accelerates the bacterial proliferation of the anti-mold plastic wrap and the accumulation of ethylene inside the anti-mold plastic wrap, causing fruit and vegetable damage. Accelerate the problem of aging, so as to achieve a better fresh-keeping effect.

Detailed ways

In order to make the purpose, features and advantages of the present invention more obvious and understandable, the specific implementation manners of the present invention will be described in detail below. In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can be implemented in many other ways different from those described here, and those skilled in the art can do similar Modifications, and thus the present invention is not limited to the specific implementations disclosed below.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The mildew-proof and fresh-keeping film of one embodiment of the present invention comprises a base film, a silicone rubber coating and a mildew-proof and fresh-keeping coating; On the side surface, the raw materials of the silicone rubber coating include the following components by weight percentage: 52% to 63% of silicone rubber, 20% to 25% of polyurethane, polyacrylic acid γ-methacryloxypropyltrimethoxysilane 12% to 18%, silicon carbide 5% to 10%, titanium dioxide 3% to 8%, and monovalent silver source 1% to 3%.

Specifically, the silicone rubber is selected from one or more of methyl silicone rubber, methyl vinyl silicone rubber, methylphenyl vinyl silicone rubber and fluorosilicone rubber.

Preferably, the silicone rubber is composed of the following components by weight percentage: 70%-80% methyl vinyl silicone rubber and 20%-30% fluorosilicone rubber, and the ethylene removal effect is better when combined with other components.

Preferably, the monovalent silver source is silver nitrate, which can more effectively absorb ethylene in the silicone rubber coating and promote the degradation of titanium dioxide, thereby improving the preservation performance of the anti-mold plastic wrap.

Preferably, the diameter of the air holes is 0.5-0.7 nm. Preferably, the distribution density of air holes is 20-40/cm ² . When the pore size and density of the air holes are within the above range, the gas separation performance of the base film can be effectively improved, so that the permeability of ethylene is greater than that of water molecules, which further ensures that the anti-mold plastic wrap is in the A state of low ethylene concentration and water vapor equilibrium.

In one embodiment, the raw materials of the anti-mold and fresh-keeping coating include the following components by weight percentage: 20%-50% of the main resin, 20%-70% of the solvent, 0.65%-25.5% of the anti-mold agent, and 0.3% of the water-retaining material. %~4% and additives 0.2%~2%. Through research, it is found that the water-retaining material of the anti-mold plastic wrap can slowly release water vapor into the anti-mold plastic wrap, thereby ensuring the humidity inside the anti-mold plastic wrap. Therefore, after adding the water-retaining material, it is necessary to appropriately increase the content of the anti-mold agent , to prevent mold growth. Therefore, the above ratio is selected. Preferably, the mass ratio of the antifungal agent to the water-retaining material is 4-6:1.

Preferably, the base film is PET film (polyethylene terephthalate film), PP film (polypropylene film), PA6 film (polyamide 6 film), EVA film (ethylene-polyvinyl acetate copolymer film) ), EVOH film (ethylene-vinyl alcohol copolymer film), PVA film (polyvinyl alcohol film) or PLA film (linear aliphatic polyester-polylactic acid film).

More preferably, the base film is PET film and PP film. PET and PP can still maintain excellent performance at temperatures as high as 120°C, which can avoid the problem of base film damage caused by heat treatment of fresh-keeping coatings to form anti-mildew fresh-keeping coatings. More preferably, the thickness of the base film is 12-22 μm.

In one of the embodiments, the host resin is selected from polyurethane, acrylic copolymer, ethylene-vinyl acetate copolymer (referred to as EVA), polyvinyl acetate copolymer (referred to as PVAC) and polyvinyl acetate with a degree of hydrolysis greater than 85%. At least one of vinyl alcohol (referred to as PVA). Among them, the degree of hydrolysis is also called the degree of alcoholysis, and polyvinyl alcohol with a degree of hydrolysis greater than 85% has good water solubility.

Preferably, the polyvinyl alcohol with a degree of hydrolysis greater than 85% in the host resin is selected from at least one of polyvinyl alcohol 1788, polyvinyl alcohol 2088 and polyvinyl alcohol 2488. Polyvinyl alcohol 1788, polyvinyl alcohol 2088 and polyvinyl alcohol 2488 are polyvinyl alcohols with good water solubility. Take polyvinyl alcohol 1788 as an example, which is a polyvinyl alcohol with a degree of polymerization of 1700 and a degree of hydrolysis of 88%.

Further, the water-retaining material is selected from at least one of hydroxyacrylate, glycerol, superabsorbent resin, porous inorganic material and polyvinyl alcohol with a degree of hydrolysis of less than 80%.

In one embodiment, the superabsorbent resin can be hydrolyzed starch, grafted acrylamide, high degree of substitution cross-linked carboxymethyl cellulose, cross-linked carboxymethyl cellulose grafted acrylamide, cross-linked hydroxyethyl fiber At least one of plain grafted acrylamide polymer, low-density cross-linked polyvinyl alcohol and polyvinyl alcohol with a degree of hydrolysis less than 80%. Further, the porous inorganic material may be porous silica, zeolite or the like.

Further, the main resin is a combination of polyvinyl acetate copolymer and polyvinyl alcohol with a degree of hydrolysis greater than 80%, and the water-retaining material is a combination of a superabsorbent resin and a porous inorganic material; wherein the superabsorbent resin has a degree of hydrolysis of less than 80%. of polyvinyl alcohol. In this way, both the main resin and the superabsorbent resin contain polyvinyl alcohol. When the two interact, the superabsorbent resin and the main resin can be connected more closely through the intermolecular interaction of the polyvinyl alcohol, avoiding the addition of the superabsorbent resin to cause the gap between the main resin. The problem of increased porosity.

Further, the porous inorganic material is porous silica. And the mass ratio of the superabsorbent resin to the porous inorganic material is 1:0.5-1. Furthermore, the mass ratio of polyvinyl acetate copolymer and polyvinyl alcohol with a degree of hydrolysis greater than 80% in the main resin is 1:0.5-1.

Preferably, the thickness of the anti-mold and fresh-keeping coating is 0.5-10 μm, and the thickness of the silicone rubber coating is 3-8 μm.

Preferably, this patent obtains a more uniformly dispersed and more stable performance antifungal agent in a large number of antifungal agents in the above-mentioned main resin through research, and the antifungal agent is selected from sorbate, citrate, dehydroacetic acid At least one of salt, pianthoxylin and catechin. Optionally, sorbate, citrate, and dehydroacetate are all sodium or potassium salts thereof.

Further, in the anti-mildew and fresh-keeping paint, by weight percentage, sorbate is 0.2% to 4%, citrate is 0.2% to 6%, dehydroacetate is 0% to 2%, and xanthoxylin 0-6%, catechin 0.25%-7.5%. Studies have found that adding catechins to sorbate and citrate can effectively improve the anti-mold effect. The main reason is that the aqueous solution of catechins is easy to polymerize to form amorphous tannins, and tannins are easily oxidized, especially in sorbic acid. Oxidation is faster under weak alkaline conditions such as acid salt and citrate, so it can be combined with protein to kill mold. Within this range, the combination of various antifungal agents has a better antifungal effect.

Furthermore, in the anti-mildew and fresh-keeping coating, by weight percentage, sorbate is 2% to 4%, citrate is 2% to 6%, dehydroacetate is 1% to 2%, and Zanthoxylum bungeanum is Catechin is 3 to 4%, and catechin is 4% to 7.5%. At the same time, xanthoxylin and dehydroacetate are added as antifungal agents to act synergistically to achieve a better antifungal effect.

Further, the antifungal agent is a combination of sorbate, citrate, dehydroacetate, xanthoxylin and catechin, and sorbate, citrate, dehydroacetate, xanthoxylin and catechin The mass ratio of tea element is 1:1～2:0.5～0.8:1～2:1～2.

In one embodiment, the solvent is selected from at least one of water and ethanol. Polyurethane, polyvinyl alcohol, ethylene-vinyl acetate copolymer, polyvinyl acetate copolymer and other water-soluble resins are used, and the solvent can be water to achieve environmental protection and cost reduction. Preferably, the solvent is a combination of ethanol and water in a volume ratio of 1:1.

In one embodiment, the auxiliary agent is at least one of surfactant, emulsifier, wetting agent, defoamer and anti-sedimentation agent. Among them, the surfactant is Tween 80 and Span, etc., and the surfactant can make the antifungal agent more uniformly dispersed in the main resin. Emulsifiers are beneficial to promote the formation of stable aqueous emulsions of poorly water-soluble resins.

The anti-mold fresh-keeping film of this embodiment is close to the surface of the anti-mold fresh-keeping coating when packaging fruits and vegetables, which can inhibit the growth of mold in the package, and is not easy to produce mildew when the fruits and vegetables are not pre-treated. The ethylene released by the fruits and vegetables in the anti-mold plastic wrap can be discharged from the air holes of the base film, and the air permeability of the side of the base film with the anti-mold and fresh-keeping coating is greater than that of the side of the base film with the silicone rubber coating, even The prepared anti-mildew fresh-keeping film has good one-way air permeability. Silicone rubber is a high-molecular elastic material with excellent comprehensive properties. The molecular chain is composed of silicon atoms and oxygen atoms alternately, and has good air permeability. Oxysilane is blended and modified, and silicon carbide inorganic powder is added to form an organic-inorganic hybrid membrane to further improve the gas separation performance. At the same time, titanium dioxide can degrade ethylene under photocatalysis, causing a difference in ethylene concentration on both sides of the base film, which provides the power for the diffusion of ethylene to the silicone rubber coating, and promotes the continuous outward diffusion of ethylene inside the base film, significantly improving the ethylene concentration. The pass rate reduces the pass rate of other gases. On the one hand, monovalent silver ions can form π-complexes with ethylene to assist in the absorption of ethylene, and promote the outward diffusion of ethylene inside the basement film; It improves the photocatalytic efficiency, removes ethylene around fruits and vegetables more efficiently, keeps the ethylene concentration at a very low level, and does not affect the respiration of fruits and vegetables, thus improving the freshness preservation effect and prolonging the freshness preservation period.

Furthermore, the water-retaining material in the anti-mold plastic wrap has strong water absorption, and absorbs the water vapor before it reaches the vent holes of the base film, and slowly releases water vapor into the anti-mold plastic wrap after reaching a certain concentration. , and then effectively inhibit the water loss of fruits and vegetables, and the presence of antifungal agents can prevent mildew in fruits and vegetables. In this way, the inside of the anti-mold plastic wrap is in a state of low ethylene concentration and water vapor balance, which further effectively avoids the condensation on the inner wall of the anti-mold plastic wrap, which accelerates the bacterial proliferation of the anti-mold plastic wrap and the accumulation of ethylene inside the anti-mold plastic wrap, causing fruit and vegetable damage. Accelerate the problem of aging, so as to achieve a better fresh-keeping effect.

The present invention also provides a method for preparing the above mildew-proof plastic wrap in an embodiment, comprising the following steps S1-S4.

Step S1: providing a base film with air holes.

Specifically, holes are drilled on the base film by laser drilling technology to form air-permeable holes. Optionally, the diameter of the air holes is 0.5-0.7 nm, and the distribution density of the air holes is 20-40/cm ² .

Step S2: blending the raw material of the silicone rubber coating with n-hexane to obtain the silicone rubber coating.

Specifically, the mass percent concentration of n-hexane in the silicone rubber coating is 99.2%-99.5%.

Step S3: Mix the main resin and the solvent uniformly to obtain a mixed liquid, add water-retaining materials, additives and anti-mold agents to the mixed liquid in sequence and mix evenly to obtain an anti-mold fresh-keeping coating.

Specifically, step S3 specifically includes the following steps: stirring the main resin and the solvent at a rotation speed of 100-300 rpm and heating to 30-65° C. for 5-15 minutes; Add water-retaining materials and additives one by one and stir for 30-60 minutes, then add the anti-fungal agent dropwise at a speed of 500-800 rpm. The time for adding the anti-fungal agent is controlled within 1-2 hours, so that fully dispersed.

Step S4: Coating silicone rubber paint on one surface of the base film and performing heat treatment to form a silicone rubber coating, coating a surface of the base film away from the silicone rubber coating and performing heat treatment to make the mildew-proof and fresh-keeping coating An anti-mildew and fresh-keeping coating is formed to obtain an anti-mildew and fresh-keeping film.

Further, the heat treatment condition is to treat at 80-120°C for 5-10s.

The preparation method of this embodiment is environmentally friendly and pollution-free. When the prepared anti-mold plastic wrap is used as a packaging material for packaging fruits and vegetables, the fruits and vegetables themselves do not need to undergo any anti-corrosion, anti-mold, sterilization, and fresh-keeping treatment. In the packaging products such as film, through the anti-mold and sterilization function of the packaging product itself and the breathable function of ethylene, it can achieve the effect of anti-mold and fresh-keeping on the placed objects in the packaging product, effectively prolong the freshness of fruits and vegetables in the process of transportation and storage, and facilitate the transportation of fruits and vegetables Packaging enterprises vigorously promote it, and the market application prospect is broad.

The following are specific examples.

Example 1

Supplied with PP film. The PP film is drilled by laser drilling technology to obtain air-permeable holes with a pore size of 0.6nm. The distribution density of air holes is 25/cm ² .

The raw material of silicone rubber coating is blended with normal hexane to obtain silicone rubber coating. The raw materials of silicone rubber coating include by weight percentage: 52% of silicone rubber, 21% of polyurethane, polyacrylic acid γ-methacryloxypropyl 13% trimethoxysilane, 6% silicon carbide, 6% titanium dioxide and 2% monovalent silver source, wherein the silicone rubber is composed of methyl silicone rubber, and the monovalent silver source is silver chloride.

The raw materials for anti-mold and fresh-keeping coatings include: 25% polyvinyl acetate copolymer, 25% polyvinyl alcohol with a hydrolysis degree of 88%, and 20% ethanol-water mixed solvent with a volume ratio of 1:1. , Potassium sorbate 4%, Sodium citrate 6%, Sodium dehydroacetate 2%, Xanthanin 6%, Catechin 7.5%, Polyvinyl alcohol 4% with a hydrolysis degree of 78% and Tween 80 is 0.5%. Stir polyvinyl acetate copolymer and polyvinyl alcohol with a degree of hydrolysis of 88% in ethanol-water mixed solvent at a rotation speed of 300 rpm and heat to 50° C. to obtain a mixed solution. Add hydroxyacrylate and Tween 80 to the mixture at a speed of 300 rpm and stir for 60 minutes, then add antifungal agents potassium sorbate, sodium citrate, and sodium dehydroacetate dropwise at a speed of 800 rpm , Xanthophyllin and catechin, the time of dropping the antifungal agent is controlled within 1 to 2 hours, mixed evenly, and the temperature is lowered to obtain an antifungal and fresh-keeping coating.

Apply the silicone rubber paint on one surface of the base film, and then treat it at 120°C for 1.2s to form a silicone rubber coating, apply the anti-mold and fresh-keeping paint on the surface of the base film away from the silicone rubber coating, and then heat it at 120°C After processing for 1.2s, a PE cling film containing an anti-mildew and fresh-keeping coating is obtained.

Example 2

The experimental procedure of Example 2 is basically the same as that of Example 1, except that in the raw material of the silicone rubber coating, the silicone rubber is composed of methylphenylvinyl silicone rubber.

Example 3

The experimental procedure of Example 3 is basically the same as that of Example 1, except that in the raw material of the silicone rubber coating, the source of monovalent silver is silver nitrate.

Example 4

The experimental procedure of Example 4 is basically the same as that of Example 3, except that in the raw material of the silicone rubber coating, the silicone rubber is composed of 76% methyl vinyl silicone rubber and 24% fluorosilicone rubber.

Example 5

The experimental procedure of Example 5 is basically the same as that of Example 1, except that the composition of the raw materials of the anti-mildew and fresh-keeping coating includes: 20% polyurethane and a 1:1 volume ratio of ethanol-water mixed solvent 70 %, 0.2% potassium sorbate, 0.2% sodium citrate, 0.25% catechin, 4% hydroxyacrylate and 0.5% Tween 80.

Example 6

The experimental procedure of embodiment 6 is basically the same as that of embodiment 1, except that the composition of the raw materials of the anti-mold and fresh-keeping coating: comprises by weight percentage: acrylate copolymer 20%, ethylene-vinyl acetate copolymer 15%, 40% ethanol water mixed solvent with a volume ratio of 1:1, 2% potassium sorbate, 2% sodium citrate, 1.6% sodium dehydroacetate, 2% prickly ash, 2% catechin %, 1.2% glycerol and 0.2% Tween 80.

Example 7

The experimental procedure of embodiment 7 is basically the same as embodiment 6, and difference is the partial composition of the raw material of anti-mold fresh-keeping coating: potassium sorbate is 2%, sodium citrate is 4%, sodium dehydroacetate is 1%, Xanthoxylum is 4%, catechin is 1%, and glycerol is 2%.

Example 8

The experimental procedure of embodiment 8 is substantially the same as that of embodiment 7, except that the partial composition of the raw material of the anti-mildew and fresh-keeping coating: the degree of hydrolysis is 78% of polyvinyl alcohol 4% replaced by the degree of hydrolysis of 78% of polyvinyl alcohol Combination of 1% and porous silica 3%.

Example 9

The experimental procedure of embodiment 9 is basically the same as that of embodiment 7, except that the partial composition of the raw material of the anti-mold fresh-keeping coating: the degree of hydrolysis is 78% polyvinyl alcohol 4% replaced by the degree of hydrolysis as polyvinyl alcohol of 78% 2% and porous silica 2%.

Example 10

The experimental procedure of Example 10 is basically the same as that of Example 1, except that in Example 10, the diameter of the air-permeable pores of the base film is 10 nm.

Example 11

The experimental procedure of embodiment 11 is basically the same as that of embodiment 9, except that in the raw material of the silicone rubber coating, the source of monovalent silver is silver nitrate, and the silicone rubber is composed of 76% methyl vinyl silicone rubber and 24% fluorosilicone rubber. composition

The experimental procedure of Comparative Examples 1 to 3 is basically the same as that of Example 1, except that the base film of Comparative Example 1 is not provided with a silicone rubber coating; the raw material of the silicone rubber coating of Comparative Example 2 does not contain polyurethane and silicon carbide The raw material of the silicone rubber coating of comparative example 3 does not contain a monovalent silver source; the raw material of the silicone rubber coating of comparative example 4 does not contain titanium dioxide.

The fresh apples were respectively wrapped with the PE plastic wraps prepared in Examples 1-11 and Comparative Examples 1-4 for testing, and the appearance changes of the apples were observed. During the test, the side with the anti-mold and fresh-keeping coating is in direct contact with the apple. The test conditions are: ambient temperature 45°C (in order to shorten the test cycle, set the test temperature to be higher than normal temperature), humidity 65%, test object: apple, test time: 15 days, the results are shown in Table 1.

Table 1

The anti-mold fresh-keeping film prepared in Example 1 was tested for the permeability of ethylene gas with the anti-mold fresh-keeping layer as the inner layer and the silicone rubber coating as the inner layer at a volatilization temperature of 100°C and a volatilization time of 60 minutes. , the transmittances of ethylene are respectively 100cm ³ /m ² ·d·Pa and 30cm ³ /m ² ·d·Pa.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (10)

1. a kind of anti-mildew fresh-keeping film, it is characterised in that including basement membrane, silicone rubber coating and anti-mildew fresh-keeping coating；The basement membrane is set There is air-vent, the silicone rubber coating is respectively formed in the both side surface of the basement membrane, the silicon with the anti-mildew fresh-keeping coating The raw material of rubber coating percentage composition by weight includes following component：Silicon rubber 52%~63%, polyurethane 20%~25%, gather Acrylic acid γ-methacryloxypropyl trimethoxy silane 12%~18%, carborundum 5%~10%, titanium dioxide 3% ~8% and monovalence silver source 1%~3%.

2. anti-mildew fresh-keeping film according to claim 1, it is characterised in that the silicon rubber is selected from methyl silicone rubber, methyl One or more in vinylsiloxane rubber, methyl phenyl vinyl silicone rubber and fluorosioloxane rubber.

3. anti-mildew fresh-keeping film according to claim 2, it is characterised in that the silicon rubber by following percentage by weight group It is grouped into：70%~80% methyl vinyl silicone rubber and 20%~30% fluorosioloxane rubber.

4. anti-mildew fresh-keeping film according to claim 1, it is characterised in that the monovalence silver source is silver nitrate.

5. anti-mildew fresh-keeping film according to claim 1, it is characterised in that the aperture of the air-vent is 0.5~0.7nm.

6. anti-mildew fresh-keeping film according to claim 5, it is characterised in that the distribution density of the air-vent is 20~40 Individual/cm²。

7. anti-mildew fresh-keeping film according to claim 1, it is characterised in that the raw material by weight hundred of the anti-mildew fresh-keeping coating Content is divided to include following component：Matrix resin 20%~50%, solvent 20%~70%, mould inhibitor 0.65%~25.5%, guarantor Water material 0.3%~4% and auxiliary agent 0.2%~2%.

8. anti-mildew fresh-keeping film according to claim 7, it is characterised in that the matrix resin is selected from polyurethane, acrylic acid Lipin polymer, ethylene-vinyl acetate analog copolymer, polyvinyl acetate copolymer and degree of hydrolysis are more than 85% polyethylene At least one of alcohol；The water-keeping material is in hydroxy acrylate, glycerine, porous inorganic material and high hydroscopic resin At least one.

9. anti-mildew fresh-keeping film according to claim 7, it is characterised in that the quality of the mould inhibitor and the water-keeping material Than for 4~6:1.

10. the preparation method of the anti-mildew fresh-keeping film described in a kind of any one of claim 1~9, it is characterised in that including following step Suddenly：

The basement membrane provided with the air-vent is provided；

The raw material of the silicone rubber coating and n-hexane blending slurrying are obtained into Silicone Rubber Based Coatings；

The matrix resin and the solvent are well mixed, obtain mixed liquor；The guarantor is sequentially added in the mixed liquor Water material, the auxiliary agent and the mould inhibitor are simultaneously well mixed, and obtain anti-mildew fresh-keeping coating；

The basement membrane a surface coated silastic coating and carry out heat treatment and form silicone rubber coating, by the anti-mildew fresh-keeping Coating is coated on the surface away from the silicone rubber coating on the basement membrane and carries out heat treatment and makes the anti-mildew fresh-keeping coating The anti-mildew fresh-keeping coating is formed, obtains the anti-mildew fresh-keeping film.