Hydrophobic membrane, coating liquid for hydrophobic membrane, preparation method and application of hydrophobic membrane

Abstract

The invention provides a hydrophobic film, a film coating liquid for the hydrophobic film, a preparation method and application of the hydrophobic film. The hydrophobic membrane comprises a bottom layer, a middle layer and a surface layer, the bottom layer is prepared from the following raw material components in parts by weight: 15 to 35 parts of high molecular weight polyethylene with weight-average molecular weight, 20 to 40 parts of modified nano ferroferric oxide and 20 to 30 parts of beewax, and the modified nano ferroferric oxide is micron silicon dioxide coated nano ferroferric oxide; the middle layer is prepared from the following raw material components in parts by weight: 5 to 10 parts of polydimethylsiloxane, 5 to 15 parts of nano silicon dioxide and 1 to 5 parts of silane; the surface layer is prepared from the following raw material components in parts by weight: 5 to 10 parts of tert-butyl isocyanate and 0.3 to 0.5 part of wood pulp cellulose. The hydrophobic film can be used for a yoghourt packaging material, has a good yoghourt-sticking-free effect and has recycling conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of packaging materials, and in particular relates to a hydrophobic film suitable for yogurt packaging materials, a coating liquid for the film, a method for preparing the film, an application of the film, and an anti-sticking yogurt packaging material formed by applying the film. Background Art

[0002] Yogurt is a milk product made from milk, which is pasteurized and then added with beneficial bacteria or fermentation agents. After fermentation, it is cooled and filled. Yogurt is widely loved by consumers because it is rich in various nutrients such as protein, fat and dietary fiber. In production, yogurt is often packaged in containers made of polypropylene plastic materials. Due to its high viscosity and poor fluidity, yogurt is very easy to adhere to the surface of yogurt packaging materials. It is unsightly to lick it and it will cause unnecessary waste if thrown away, which brings troubles to consumers.

[0003] The prior art mostly adopts the method of coating a layer of polyvinylidene chloride latex on the surface of yogurt packaging materials to reduce the adhesion of yogurt on the surface of packaging materials. However, the anti-adhesion effect of yogurt in this method is poor, and the phenomenon of yogurt adhering to the surface of packaging materials still exists. In addition, the yogurt cover film coated with polyvinylidene chloride latex cannot be recycled, and other materials compounded with it cannot be recycled and reused. When the waste containing polyvinylidene chloride latex is incinerated, hydrogen chloride, dioxin and other substances that are toxic and harmful to the human body and the surrounding environment will be generated, making it difficult to dispose of the waste. Summary of the invention

[0004] The purpose of the present invention is to provide a hydrophobic film which is suitable for yogurt packaging materials, has a good non-stick yogurt effect and is recyclable, as well as a coating liquid for the hydrophobic film, a preparation method of the hydrophobic film, an application of the hydrophobic film, and an anti-stick yogurt packaging material.

[0005] In order to achieve the above-mentioned purpose, the present invention provides the following technical solutions.

[0006] In a first aspect, the present invention provides a hydrophobic membrane, wherein the hydrophobic membrane comprises a bottom layer, a middle layer and a surface layer; wherein,

[0007] The raw material components of the bottom layer include: 15-35 parts by weight of high molecular weight polyethylene, 20-40 parts by weight of modified nano-ferroferric oxide, and 20-30 parts by weight of beeswax; wherein the modified nano-ferroferric oxide is micron silicon dioxide coated nano-ferroferric oxide;

[0008] The weight average molecular weight of the high molecular weight polyethylene is 100,000 or more.

[0009] The raw material components of the middle layer include: 5-10 parts by weight of polydimethylsiloxane, 5-15 parts by weight of nano silicon dioxide and 1-5 parts by weight of silane;

[0010] The surface layer comprises the following raw material components: 5-10 parts by weight of tert-butyl isocyanate and 0.3-0.5 parts by weight of wood pulp cellulose.

[0011] The hydrophobic film obtained by the present invention by using a specific bottom layer in combination with a specific middle layer and a surface layer has an excellent non-stick yogurt effect, and at the same time has good adhesion to the substrate, good hardness and wear resistance, good high temperature resistance and chemical stability, so that it has the conditions for recycling while having the excellent non-stick yogurt effect.

[0012] The bottom layer raw material of the present invention selects high molecular weight polyethylene 15-35 weight parts, modified nano ferroferric oxide 20-40 weight parts and beeswax 20-30 weight parts, and each raw material dosage can be selected from any value in the respective range, and the non-adhesion yogurt effect of the hydrophobic film obtained by coordinating with a specific middle layer and a surface layer, the adhesion to the substrate, hardness and abrasion resistance, high temperature resistance and chemical stability are all good. The structure of nano ferroferric oxide is tight and chemically stable, and it has excellent adhesion while having hydrophobicity, can improve the adhesion of the bottom layer and the substrate on the one hand, and can further improve the hydrophobicity of the bottom layer on the other hand. The addition of beeswax can effectively reduce the water vapor permeability of the film, improve the anti-adhesion performance of the film, and reduce the adhesion of yogurt to the surface of the packaging material. By coating nano-ferroferric oxide with micron silicon dioxide, on the one hand, a micron-level hydrophobic synapse is formed, which can cover more active groups on the surface of the substrate, such as hydroxyl, carboxyl, sulfonic acid, amide, ether bond, etc., to effectively prevent yogurt from adhering to the surface of the packaging material. On the other hand, the use of micron silicon dioxide to coat nano-ferroferric oxide can improve the dispersion of nano-ferroferric oxide in the bottom layer, further improve the hydrophobicity of the bottom layer, and improve the effect of reducing the adhesion of yogurt to the surface of the packaging material. High molecular weight polyethylene is non-toxic and tasteless, has excellent high temperature resistance and chemical stability, and has high adhesion performance, which makes the adhesion between the bottom layer and the substrate, thereby ensuring the hydrophobicity of the bottom layer and improving the problem of yogurt adhering to the surface of the packaging material.

[0013] The middle layer raw materials of the present invention are selected from 5-10 parts by weight of polydimethylsiloxane, 5-15 parts by weight of nano silicon dioxide and 1-5 parts by weight of silane. The dosage of each raw material can be selected from any value within the respective range. The hydrophobic film obtained by cooperating with a specific bottom layer and surface layer has good non-adhesive yogurt effect, adhesion to the substrate, hardness and wear resistance, high temperature resistance and chemical stability. The middle layer covers the surface of the bottom layer, and most of the active groups on the surface of the bottom layer can be eliminated, leaving only part of the hydroxyl group, forming a super-hydrophobic nanostructure. Among them, polydimethylsiloxane is a hydrophobic organosilicon material with high transparency, heat resistance, cold resistance, waterproofness, small surface tension, and high hydrophobicity. Nano silicon dioxide has high hydrophobicity on the one hand, and can improve the adhesion of the middle layer on the other hand, improve the wear resistance of the middle layer, and the addition of silane can further improve the adhesion of the middle layer on the surface of the bottom layer.

[0014] The surface layer raw materials of the present invention are selected from 5-10 parts by weight of tert-butyl isocyanate and 0.3-0.5 parts by weight of wood pulp cellulose. The dosage of each raw material can be selected from any value within the respective ranges. The hydrophobic film obtained by combining with the specific bottom layer and middle layer has good non-adhesion yogurt effect, adhesion to the substrate, hardness and wear resistance, high temperature resistance and chemical stability. Tert-butyl isocyanate can remove the active groups remaining on the surface of the middle layer, and react with hydroxyl groups to inactivate the hydroxyl groups, reduce the binding force generated between the active groups and the yogurt, and effectively improve the effect of reducing the adhesion of yogurt to the surface of the packaging material. Wood pulp cellulose has good thickening, suspension, dispersion, emulsification, bonding and film-forming effects, can improve the stability of tert-butyl isocyanate, and prevent the surface layer from cracking.

[0015] The bottom layer, middle layer and surface layer of the present invention can be prepared by coating and drying the coating liquid (ie, coating and curing). The bottom layer, middle layer and surface layer may contain a trace amount of residual solvent that is not completely removed during the drying process.

[0016] According to a preferred embodiment of the first aspect, the bottom layer comprises the following raw material components: 20-30 parts by weight of the high molecular weight polyethylene, 25-35 parts by weight of the modified nano-ferroferric oxide, and 24-28 parts by weight of the beeswax;

[0017] Furthermore, when the bottom layer includes 25 parts by weight of high molecular weight polyethylene, 30 parts by weight of modified nano-ferroferric oxide and 25 parts by weight of beeswax, the effect is better;

[0018] By adopting the above technical solution, when the addition amounts of high molecular weight polyethylene, modified nano-ferroferric oxide and beeswax are controlled within the above ranges, it helps to further reduce the adhesion of yogurt to the surface of the packaging material.

[0019] According to a preferred embodiment of the first aspect, the modified nano-ferroferric oxide can be prepared by the following method:

[0020] Mixing nano-ferroferric oxide with anhydrous ethanol and ethyl orthosilicate, adding ammonia water at 40-50° C., stirring, filtering, drying and crushing to obtain the modified nano-ferroferric oxide;

[0021] Further, the weight ratio of ferrosoferric oxide to ethyl orthosilicate is 1-3:5-10;

[0022] Furthermore, the usage ratio of ferrosoferric oxide to anhydrous ethanol is 1-3kg:5-10L;

[0023] Furthermore, the mass concentration of the ammonia water is 20-30%, and the dosage ratio of the ammonia water to ferrosoferric oxide is 1-3kg:40-60mL;

[0024] By adopting the above technical scheme, nano-ferroferric oxide is first mixed with anhydrous ethanol and ethyl orthosilicate, the nano-ferroferric oxide is dissolved in anhydrous ethanol, ethyl orthosilicate is added as a silicon source, and after adding ammonia water, it undergoes hydrolysis and condensation reactions to coat the surface of the nano-ferroferric oxide with silicon dioxide, and then filtered, dried, and crushed to obtain modified nano-ferroferric oxide. The modified nano-ferroferric oxide further improves the hydrophobicity of the bottom layer and reduces the adhesion of yogurt on the surface of the packaging material.

[0025] According to a preferred embodiment of the first aspect, the raw material component silane of the middle layer includes one or a combination of two or more of trimethylmethoxysilane, trimethylethoxysilane, trimethylchlorosilane, triethylmethoxysilane, triethylethoxysilane, and triethylchlorosilane.

[0026] According to a preferred embodiment of the first aspect, when the middle layer comprises 8 parts by weight of polydimethylsiloxane, 10 parts by weight of nano silicon dioxide and 3 parts by weight of trimethylmethoxysilane, the effect is better.

[0027] According to a preferred embodiment of the first aspect, when the surface layer comprises 8 parts by weight of tert-butyl isocyanate and 0.4 parts by weight of wood pulp cellulose, the effect is better.

[0028] According to a preferred embodiment of the first aspect, the surface layer further comprises 5-10 parts by weight of calcium stearate and 10-20 parts by weight of glyceryl tristearate;

[0029] By adopting the above technical solution, calcium stearate is added as a hydrophobic filler to further improve the hydrophobicity and structural density of the surface layer, and tristearate glyceryl can improve the dispersion uniformity of calcium stearate in the surface layer, thereby further improving the hydrophobicity of the surface layer;

[0030] Further, the weight ratio of the calcium stearate to the glyceryl tristearate is 1:2-3;

[0031] By adopting the above technical solution and adjusting the weight ratio of calcium stearate to glyceryl tristearate, the dispersion uniformity of calcium stearate in the surface layer can be further improved.

[0032] According to a preferred embodiment of the first aspect, the surface layer further comprises 1-3 parts by weight of fatty alcohol polyoxyethylene ether;

[0033] By adopting the above technical solution and adding fatty alcohol polyoxyethylene ether, the dispersion uniformity of wood pulp cellulose can be improved, thereby improving the stability of the surface layer and improving the anti-stickiness of the surface layer, thereby further reducing the adhesion of yogurt to the surface of the packaging material.

[0034] In a second aspect, the present invention provides the hydrophobic film coating liquid of the first aspect, wherein the hydrophobic film coating liquid comprises a first coating liquid, a second coating liquid and a third coating liquid which are stored separately;

[0035] The first coating solution comprises the following components: raw material components of the bottom layer of the hydrophobic film (15-35 parts by weight of high molecular weight polyethylene, 20-40 parts by weight of modified nano ferroferric oxide, 20-30 parts by weight of beeswax, wherein the modified nano ferroferric oxide is micron silicon dioxide coated nano ferroferric oxide, and the weight average molecular weight of the high molecular weight polyethylene is more than 100,000) and a solvent;

[0036] The second coating solution comprises the following components: raw material components of the middle layer of the hydrophobic film (5-10 parts by weight of polydimethylsiloxane, 5-15 parts by weight of nano-silicon dioxide and 1-5 parts by weight of silane) and a solvent;

[0037] The third coating liquid comprises the following components: raw material components of the surface layer of the hydrophobic film (5-10 parts by weight of tert-butyl isocyanate, 0.3-0.5 parts by weight of wood pulp cellulose, optionally 5-10 parts by weight of calcium stearate and 10-20 parts by weight of tristearate glyceryl, optionally 1-3 parts by weight of fatty alcohol polyoxyethylene ether) and a solvent;

[0038] Wherein, in the first coating solution, the weight ratio of the total mass of the raw material components of the bottom layer of the hydrophobic film to the solvent is 1:1-25;

[0039] Wherein, in the second coating solution, the weight ratio of the total mass of the raw material components of the middle layer of the hydrophobic film to the solvent is 1:1-25;

[0040] Wherein, in the third coating solution, the weight ratio of the total mass of the raw material components of the surface layer of the hydrophobic film to the solvent is 1:1-25.

[0041] The first coating liquid in the coating liquid for hydrophobic film provided by the second aspect of the present invention is formed by mixing the raw material components of the bottom layer of the hydrophobic film provided by the first aspect of the present invention with a solvent, the second coating liquid is formed by mixing the raw material components of the middle layer of the hydrophobic film provided by the first aspect of the present invention with a solvent, and the third coating liquid is formed by mixing the raw material components of the surface layer of the hydrophobic film provided by the first aspect of the present invention with a solvent. The bottom layer of the hydrophobic film provided in the first aspect of the present invention can be obtained by coating and drying the first coating liquid in the coating liquid provided in the second aspect of the present invention (that is, the bottom layer of the hydrophobic film provided in the first aspect of the present invention can be obtained by coating and drying the first coating liquid in the coating liquid provided in the second aspect of the present invention); the middle layer of the hydrophobic film provided in the first aspect of the present invention can be obtained by coating and drying the second coating liquid in the coating liquid provided in the second aspect of the present invention (that is, the middle layer of the hydrophobic film provided in the first aspect of the present invention can be obtained by coating and drying the second coating liquid in the coating liquid provided in the second aspect of the present invention); the surface layer of the hydrophobic film provided in the first aspect of the present invention can be obtained by coating and drying the third coating liquid in the coating liquid provided in the second aspect of the present invention (that is, the surface layer of the hydrophobic film provided in the first aspect of the present invention can be obtained by coating and drying the third coating liquid in the coating liquid provided in the second aspect of the present invention).

[0042] According to a preferred embodiment of the second aspect, the component solvent of the first coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol.

[0043] According to a preferred embodiment of the second aspect, the raw material components of the first coating solution include: 20-30 parts by weight of the high molecular weight polyethylene, 25-35 parts by weight of the modified nano-ferroferric oxide, and 24-28 parts by weight of the beeswax;

[0044] Furthermore, when the raw material components of the first coating solution include 25 parts by weight of high molecular weight polyethylene, 30 parts by weight of modified nano-ferroferric oxide, and 25 parts by weight of beeswax, the effect is better.

[0045] According to a preferred embodiment of the second aspect, the modified nano-ferroferric oxide can be prepared by the following method:

[0046] Mixing nano-ferroferric oxide with anhydrous ethanol and ethyl orthosilicate, adding ammonia water at 40-50° C., stirring, filtering, drying and crushing to obtain the modified nano-ferroferric oxide;

[0047] Further, the weight ratio of ferrosoferric oxide to ethyl orthosilicate is 1-3:5-10;

[0048] Furthermore, the usage ratio of ferrosoferric oxide to anhydrous ethanol is 1-3kg:5-10L;

[0049] Furthermore, the mass concentration of the ammonia water is 20-30%, and the usage ratio of the ammonia water to ferrosoferric oxide is 1-3kg:40-60mL.

[0050] According to a preferred embodiment of the second aspect, the raw material component solvent of the second coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol.

[0051] According to a preferred embodiment of the second aspect, the raw material component silane of the second coating solution includes one or a combination of two or more of trimethylmethoxysilane, trimethylethoxysilane, trimethylchlorosilane, triethylmethoxysilane, triethylethoxysilane, and triethylchlorosilane.

[0052] According to a preferred embodiment of the second aspect, when the raw material components of the second coating solution include 8 parts by weight of polydimethylsiloxane, 10 parts by weight of nano-silicon dioxide and 3 parts by weight of trimethylmethoxysilane, the effect is better.

[0053] According to a preferred embodiment of the second aspect, the raw material component solvent of the third coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol.

[0054] According to a preferred embodiment of the second aspect, when the raw material components of the third coating solution include 8 parts by weight of tert-butyl isocyanate and 0.4 parts by weight of wood pulp cellulose, the effect is better.

[0055] According to a preferred embodiment of the second aspect, when the raw material components of the third coating solution include 5-10 parts by weight of calcium stearate and 10-20 parts by weight of tristearate, the effect is better;

[0056] Furthermore, the weight ratio of the calcium stearate to the glyceryl tristearate is 1:2-3.

[0057] According to a preferred embodiment of the second aspect, when the raw material components of the third coating liquid include 1-3 parts by weight of fatty alcohol polyoxyethylene ether, the effect is better.

[0058] According to a preferred embodiment of the second aspect, the hydrophobic film coating liquid can be prepared by the following method:

[0059] Mixing high molecular weight polyethylene, modified nano-ferroferric oxide, beeswax and solvent to obtain a first coating solution;

[0060] Mixing polydimethylsiloxane, nano-silicon dioxide, silane and solvent to obtain a second coating solution;

[0061] Tert-butyl isocyanate, wood pulp cellulose, optionally calcium stearate and tristearic glycerol, optionally fatty alcohol polyoxyethylene ether, and a solvent are mixed to obtain a third coating liquid.

[0062] In a third aspect, the present invention provides a method for preparing the hydrophobic membrane in the first aspect, wherein the method comprises:

[0063] The first coating liquid, the second coating liquid and the third coating liquid of the hydrophobic film coating liquid provided in the second aspect are sequentially coated on the surface of the substrate from bottom to top and cured (curing is performed after each coating liquid is applied) to obtain the hydrophobic film.

[0064] According to a preferred embodiment of the second aspect, the curing temperature is 40°C-80.

[0065] The hydrophobic membrane provided by the invention has simple preparation process, convenient operation, low cost and broad application prospect.

[0066] According to a preferred embodiment of the third aspect, the preparation method comprises:

[0067] Mixing high molecular weight polyethylene, modified nano-ferroferric oxide, beeswax, and solvent (i.e., mixing the raw material components contained in the bottom layer of the hydrophobic film in the first aspect with the solvent) to obtain a first coating liquid (i.e., the first coating liquid in the hydrophobic film coating liquid provided in the second aspect);

[0068] Mixing polydimethylsiloxane, nano-silicon dioxide, silane, and solvent (i.e., mixing the raw material components contained in the middle layer of the hydrophobic film in the first aspect with the solvent) to obtain a second coating liquid (i.e., the second coating liquid in the hydrophobic film coating liquid provided in the second aspect);

[0069] Mix tert-butyl isocyanate, wood pulp cellulose, optionally calcium stearate and tristearate, optionally fatty alcohol polyoxyethylene ether, and solvent (i.e., mix the raw material components contained in the surface layer of the hydrophobic film in the first aspect with the solvent) to obtain a third coating liquid (i.e., the third coating liquid in the hydrophobic film coating liquid provided in the second aspect);

[0070] The first coating liquid, the second coating liquid and the third coating liquid are sequentially coated on the surface of the substrate from bottom to top and cured to obtain the hydrophobic film.

[0071] In a fourth aspect, the present invention provides the use of the hydrophobic film in the first aspect in a yogurt packaging material.

[0072] In a fifth aspect, the present invention provides an anti-sticking yogurt packaging material, wherein the surface of the anti-sticking yogurt packaging material is coated with the hydrophobic film in the first aspect.

[0073] The anti-sticking yogurt packaging material can be prepared by the following method:

[0074] Mixing high molecular weight polyethylene, modified nano-ferroferric oxide, beeswax, and solvent (i.e., mixing the raw material components contained in the bottom layer of the hydrophobic film in the first aspect with the solvent) to obtain a first coating liquid (i.e., the first coating liquid in the hydrophobic film coating liquid provided in the second aspect);

[0075] Mixing polydimethylsiloxane, nano-silicon dioxide, silane, and solvent (i.e., mixing the raw material components contained in the middle layer of the hydrophobic film in the first aspect with the solvent) to obtain a second coating liquid (i.e., the second coating liquid in the hydrophobic film coating liquid provided in the second aspect);

[0076] Mix tert-butyl isocyanate, wood pulp cellulose, optionally calcium stearate and tristearate, optionally fatty alcohol polyoxyethylene ether, and solvent (i.e., mix the raw material components contained in the surface layer of the hydrophobic film in the first aspect with the solvent) to obtain a third coating liquid (i.e., the third coating liquid in the hydrophobic film coating liquid provided in the second aspect);

[0077] The first coating liquid, the second coating liquid and the third coating liquid are sequentially coated on the surface of the yogurt packaging material from bottom to top, and are cured to obtain the anti-sticking yogurt packaging material.

[0078] According to a preferred embodiment of the fifth aspect, the yogurt packaging material includes but is not limited to one or a combination of two or more of PE, LLDPE, LDPE, HDPE, EVA, modified EVA, etc.

[0079] In summary, compared with the prior art, the technical solution provided by the present invention has the following effects:

[0080] (1) The present invention achieves a hydrophobic film with a surface roughness, a water contact angle, and a yogurt contact angle of 1.19-1.22 μm, 156-158°, and 138-141°, respectively, and a surface hydroxyl density and a yogurt rolling angle of (6.8-7.0)×10 3 Pieces / mm 2 and 19-21°, which improves the effect of yogurt not adhering to the surface of packaging materials.

[0081] In the preferred technical solution of the present invention, by adding calcium stearate and tristearate to the surface layer of the hydrophobic film and controlling the weight ratio of the two, the surface roughness, water contact angle and yogurt contact angle of the hydrophobic film are respectively 1.30-1.32 μm, 166-168° and 146-148°, and the surface hydroxyl density and yogurt rolling angle are respectively (5.7-5.9)×10 3 Pieces / mm 2and 12-13°, further improving the effect of yogurt not adhering to the surface of packaging materials.

[0082] In the preferred technical scheme of the present invention, by adding fatty alcohol polyoxyethylene ether to the surface layer raw materials of the hydrophobic membrane on the basis of calcium stearate and tristearate glyceryl, and controlling the dosage of fatty alcohol polyoxyethylene ether, the surface roughness, water contact angle and yogurt contact angle of the hydrophobic membrane are respectively 1.34 μm, 172° and 151°, and the surface hydroxyl density and yogurt rolling angle are respectively 5.4×10 3 Pieces / mm 2 and 10°, further improving the effect of yogurt not adhering to the surface of packaging materials.

[0083] (2) The hardness of the anti-sticking yogurt packaging material made of the hydrophobic film provided by the present invention is between HB and H, and all of them are qualified after the wear resistance test, and have high hardness and wear resistance.

[0084] (3) The hydrophobic film provided by the present invention has good adhesion to the substrate, high temperature resistance and chemical stability.

[0085] (4) The hydrophobic film provided by the present invention has excellent yogurt non-adhesion performance, adhesion performance to the substrate, hardness and wear resistance, high temperature resistance and chemical stability, making it suitable for recycling. DETAILED DESCRIPTION

[0086] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the content specifically described below is illustrative and non-restrictive, and protection scope of the present invention should not be limited by this. Efforts have been made to ensure the accuracy of numbers (such as amounts, temperatures, etc.), but some errors and deviations should be taken into account.

[0087] A specific embodiment of the present invention provides a hydrophobic membrane, the hydrophobic membrane comprises a bottom layer, a middle layer and a surface layer;

[0088] The raw material components of the bottom layer include: 15-35 parts by weight of high molecular weight polyethylene, 20-40 parts by weight of modified nano ferroferric oxide, and 20-30 parts by weight of beeswax; wherein the modified nano ferroferric oxide is micron silicon dioxide coated nano ferroferric oxide, and the weight average molecular weight of the high molecular weight polyethylene is more than 100,000;

[0089] The raw material components of the middle layer include: 5-10 parts by weight of polydimethylsiloxane, 5-15 parts by weight of nano silicon dioxide and 1-5 parts by weight of silane;

[0090] The raw material components of the surface layer include: 5-10 parts by weight of tert-butyl isocyanate and 0.3-0.5 parts by weight of wood pulp cellulose.

[0091] Wherein, the modified nano-ferroferric oxide is prepared by the following method:

[0092] The modified nano-ferroferric oxide is obtained by mixing nano-ferroferric oxide with anhydrous ethanol and tetraethyl orthosilicate, adding ammonia water with a mass concentration of 20-30% at 40-50° C., stirring, filtering, drying and crushing. The weight ratio of ferroferric oxide to tetraethyl orthosilicate is 1-3:5-10, the dosage ratio of ferroferric oxide to anhydrous ethanol is 1-3kg:5-10L, and the dosage ratio of ammonia water to ferroferric oxide is 1-3kg:40-60mL.

[0093] The raw material components of the surface layer also include 5-10 parts by weight of calcium stearate and 10-20 parts by weight of glyceryl tristearate; wherein the weight ratio of calcium stearate to the glyceryl tristearate is 1:2-3.

[0094] The raw material components of the surface layer also include 1-3 parts by weight of fatty alcohol polyoxyethylene ether.

[0095] The raw material component silane of the middle layer includes one or a combination of two or more of trimethylmethoxysilane, trimethylethoxysilane, trimethylchlorosilane, triethylmethoxysilane, triethylethoxysilane, and triethylchlorosilane.

[0096] Another specific embodiment of the present invention provides a coating agent for a hydrophobic film, wherein the coating liquid for a hydrophobic film comprises a first coating liquid, a second coating liquid and a third coating liquid which are stored separately;

[0097] The first coating solution includes a mixture of raw material components of the bottom layer of the hydrophobic film provided in the above specific embodiment and a solvent;

[0098] The second coating liquid comprises a mixture of the raw material components of the middle layer of the hydrophobic film provided in the above specific embodiment and a solvent;

[0099] The third coating liquid comprises a mixture of the raw material components of the surface layer of the hydrophobic film provided in the above specific embodiment and a solvent;

[0100] Wherein, in the first coating solution, the weight ratio of the total mass of the raw material components of the bottom layer of the hydrophobic film to the solvent is 1:1-25;

[0101] Wherein, in the second coating solution, the weight ratio of the total mass of the raw material components of the middle layer of the hydrophobic film to the solvent is 1:1-25;

[0102] Wherein, in the third coating solution, the weight ratio of the total mass of the raw material components of the surface layer of the hydrophobic film to the solvent is 1:1-25.

[0103] The raw material component solvent of the first coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol.

[0104] The raw material component solvent of the second coating liquid includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol.

[0105] The raw material component solvent of the third coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol.

[0106] Another specific embodiment of the present invention provides a method for preparing the hydrophobic membrane provided in the above specific embodiment, which specifically comprises the following steps:

[0107] Mixing high molecular weight polyethylene, modified nano-ferroferric oxide, beeswax and solvent (i.e., mixing the raw material components and solvent contained in the bottom layer of the hydrophobic film in the above specific embodiment) to obtain a first coating liquid (i.e., the first coating liquid in the hydrophobic film coating liquid provided in the above specific embodiment);

[0108] Mixing polydimethylsiloxane, nano-silicon dioxide, silane, and solvent (i.e., mixing the raw material components and solvent contained in the middle layer of the hydrophobic film in the above specific embodiment) to obtain a second coating liquid (i.e., the second coating liquid in the hydrophobic film coating liquid provided in the above specific embodiment);

[0109] Mix tert-butyl isocyanate, wood pulp cellulose, optionally calcium stearate and tristearate, optionally fatty alcohol polyoxyethylene ether, and solvent (i.e., mix the raw material components and solvent contained in the surface layer of the hydrophobic film in the above specific embodiment) to obtain a third coating liquid (i.e., the third coating liquid in the coating liquid for hydrophobic film provided in the above specific embodiment);

[0110] The first coating liquid, the second coating liquid and the third coating liquid are sequentially coated on the surface of the substrate from bottom to top and cured to obtain the hydrophobic film.

[0111] Another specific embodiment of the present invention provides the use of the hydrophobic film provided in the above specific embodiment in yogurt packaging materials.

[0112] Another specific embodiment of the present invention provides an anti-sticking yogurt packaging material, wherein the surface of the anti-sticking yogurt packaging material is coated with the hydrophobic film provided in the above specific embodiment.

[0113] Wherein, the anti-sticking yogurt packaging material is prepared by the following method:

[0114] Mixing high molecular weight polyethylene, modified nano-ferroferric oxide, beeswax and solvent (i.e., mixing the raw material components and solvent contained in the bottom layer of the hydrophobic film in the above specific embodiment) to obtain a first coating liquid (i.e., the first coating liquid in the hydrophobic film coating liquid provided in the above specific embodiment);

[0115] Mixing polydimethylsiloxane, nano-silicon dioxide, silane, and solvent (i.e., mixing the raw material components and solvent contained in the middle layer of the hydrophobic film in the above specific embodiment) to obtain a second coating liquid (i.e., the second coating liquid in the hydrophobic film coating liquid provided in the above specific embodiment);

[0116] Mix tert-butyl isocyanate, wood pulp cellulose, optionally calcium stearate and tristearate, optionally fatty alcohol polyoxyethylene ether, and solvent (i.e., mix the raw material components and solvent contained in the surface layer of the hydrophobic film in the above specific embodiment) to obtain a third coating liquid (i.e., the third coating liquid in the coating liquid for hydrophobic film provided in the above specific embodiment);

[0117] The first coating liquid, the second coating liquid and the third coating liquid are sequentially coated on the surface of the yogurt packaging material from bottom to top and solidified to obtain the anti-sticking yogurt packaging material.

[0118] The yogurt packaging material includes but is not limited to one or a combination of two or more of PE, HDPE, LLDPE, LDPE, EVA, modified EVA, etc.

[0119] The technical solution provided by the present invention is further described in detail below in conjunction with embodiments, comparative examples and performance testing experiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0120] Materials used in the embodiments of the present invention:

[0121] High molecular weight polyethylene: brand Japan Mitsui, grade L3000, molecular weight 9 million;

[0122] Beeswax: 99% effective substance content;

[0123] Nano-iron tetroxide: particle size is 80 mesh;

[0124] Ethyl orthosilicate: the effective substance content is 40%;

[0125] Polydimethylsiloxane: effective substance content is 99.8%, molecular weight 6000-8000;

[0126] Nano silicon dioxide: particle size is 80 mesh;

[0127] Trimethylmethoxysilane: The effective substance content is 99%;

[0128] Tert-butyl isocyanate: effective substance content is 99%;

[0129] Wood pulp cellulose: particle size is 80 mesh, brand ARBOCEL FD40;

[0130] Calcium stearate: particle size is 800 mesh;

[0131] Tristearate: The effective substance content is 99%;

[0132] Fatty alcohol polyoxyethylene ether: The active substance content is 99%, brand AEO-7.

[0133] Preparation Example

[0134] Preparation Example 1

[0135] This preparation example provides a modified nano-ferroferric oxide. It is prepared by the following method:

[0136] 2 kg of nano-ferrosoferric oxide was mixed with 6 L of anhydrous ethanol and 4 kg of ethyl orthosilicate, and 50 mL of 25% ammonia water was added at 50° C. The mixture was stirred evenly, filtered, dried, and crushed to obtain modified nano-ferrosoferric oxide.

[0137] Preparation Example 2

[0138] This preparation example provides a modified nano-ferrosoferric oxide. The difference between this preparation example and preparation example 1 is that the amount of ethyl orthosilicate used is different, specifically 5 kg.

[0139] Preparation Example 3

[0140] This preparation example provides a modified nano-ferrosoferric oxide. The difference between this preparation example and preparation example 1 is that the amount of ethyl orthosilicate used is different, specifically 8 kg.

[0141] Preparation Example 4

[0142] This preparation example provides a modified nano-ferrosoferric oxide. The difference between this preparation example and preparation example 1 is that the amount of ethyl orthosilicate used is different, specifically 10 kg.

[0143] Preparation Example 5

[0144] This preparation example provides a modified nano-ferrosoferric oxide. The difference between this preparation example and preparation example 1 is that the amount of ethyl orthosilicate used is different, specifically 11 kg.

[0145] Example

[0146] Example 1

[0147] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The hydrophobic film and the anti-sticking yogurt packaging material are prepared by the following method:

[0148] Mix high molecular weight polyethylene, modified nano-ferroferric oxide, beeswax and solvent to obtain a first coating liquid (i.e., a coating liquid for the bottom layer);

[0149] Mixing polydimethylsiloxane, nano-silicon dioxide, trimethylmethoxysilane and solvent to obtain a second coating solution;

[0150] Mixing tert-butyl isocyanate, wood pulp cellulose and solvent to obtain a third coating solution;

[0151] The first coating liquid, the second coating liquid and the third coating liquid are sequentially coated on the surface of the yogurt packaging material from bottom to top and dried and solidified at 60°C (that is, the first coating liquid is coated on the surface of the yogurt packaging material and dried and solidified at 60°C to form a bottom layer, and then the second coating liquid is coated on the bottom layer and dried and solidified at 60°C to form a middle layer, and then the third coating liquid is coated on the middle layer and dried and solidified at 60°C to form a surface layer), to obtain an anti-sticking yogurt packaging material and the hydrophobic film attached to the surface of the yogurt packaging material (LLDPE).

[0152] The amount of each component and the source of the modified nano-ferroferric oxide are shown in Table 1.

[0153] Example 2

[0154] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 1 is that the components and amounts of the first coating liquid (ie, the coating liquid for the bottom layer) are different, see Table 1 for details.

[0155] Example 3

[0156] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 1 is that the components and amounts of the first coating liquid (ie, the coating liquid for the bottom layer) are different, see Table 1 for details.

[0157] Example 4

[0158] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 2 is that the source of the modified nano-ferrosoferric oxide is different, see Table 1 for details.

[0159] Example 5

[0160] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 2 is that the source of the modified nano-ferrosoferric oxide is different, see Table 1 for details.

[0161] Example 6

[0162] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 2 is that the source of the modified nano-ferrosoferric oxide is different, see Table 1 for details.

[0163] Example 7

[0164] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 2 is that the source of the modified nano-ferrosoferric oxide is different, see Table 1 for details.

[0165] Example 8

[0166] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 5 is that the components and amounts of the third coating liquid (ie, the coating liquid for the surface layer) are different, see Table 1 for details.

[0167] Example 9

[0168] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 5 is that the components and amounts of the third coating liquid (ie, the coating liquid for the surface layer) are different, see Table 1 for details.

[0169] Example 10

[0170] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 5 is that the components and amounts of the third coating liquid (ie, the coating liquid for the surface layer) are different, see Table 1 for details.

[0171] Embodiment 11

[0172] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 5 is that the components and amounts of the third coating liquid (ie, the coating liquid for the surface layer) are different, see Table 1 for details.

[0173] Example 12

[0174] The present embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between the present embodiment and the embodiment 9 is that the components of the third coating liquid (i.e., the coating liquid for the surface layer) are different. In the present embodiment, the third coating liquid further includes calcium stearate and tristearic acid glyceryl, and the third coating liquid is obtained by mixing tert-butyl isocyanate, wood pulp cellulose, calcium stearate and tristearic acid glyceryl. The specific amount of each component is shown in Table 2.

[0175] Embodiment 13

[0176] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 12 is that the amounts of calcium stearate and tristearate glyceryl are different, see Table 2 for details.

[0177] Embodiment 14

[0178] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 12 is that the amounts of calcium stearate and tristearate glyceryl are different, see Table 2 for details.

[0179] Embodiment 15

[0180] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 12 is that the amounts of calcium stearate and tristearate glyceryl are different, see Table 2 for details.

[0181] Example 16

[0182] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 12 is that the amounts of calcium stearate and tristearate glyceryl are different, see Table 2 for details.

[0183] Embodiment 17

[0184] The present embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between the present embodiment and the embodiment 14 is that the components of the third coating liquid (i.e., the coating liquid for the surface layer) are different. In the present embodiment, the third coating liquid further includes fatty alcohol polyoxyethylene ether, and the third coating liquid is obtained by mixing tert-butyl isocyanate, wood pulp cellulose, calcium stearate, tristearate glyceryl, and fatty alcohol polyoxyethylene ether. The specific amount of each component is shown in Table 2.

[0185] Embodiment 18

[0186] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 17 is that the amount of fatty alcohol polyoxyethylene ether is different, see Table 2 for details.

[0187] Embodiment 19

[0188] This embodiment provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this embodiment and embodiment 17 is that the amount of fatty alcohol polyoxyethylene ether is different, see Table 2 for details.

[0189] Table 1

[0190]

[0191] Table 2

[0192]

[0193]

[0194] Comparative Example

[0195] Comparative Example 1

[0196] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this comparative example and Example 1 is that no modified nano-ferrosoferric oxide is added.

[0197] Comparative Example 2

[0198] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. This comparative example is different from Example 1 in that no beeswax is added.

[0199] Comparative Example 3

[0200] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this comparative example and Example 1 is that nano ferrosoferric oxide is used instead of modified nano ferrosoferric oxide.

[0201] Comparative Example 4

[0202] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this comparative example and Example 1 is that only the first coating liquid is coated on the surface of the yogurt packaging material and dried and solidified at 60° C., and the second coating liquid and the third coating liquid are not coated.

[0203] Comparative Example 5

[0204] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this comparative example and Example 1 is that only the first coating liquid and the second coating liquid are sequentially coated on the surface of the yogurt packaging material from bottom to top and dried and solidified at 60°C, and the third coating liquid is not coated.

[0205] Comparative Example 6

[0206] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this comparative example and Example 1 is that only the second coating liquid and the third coating liquid are sequentially coated on the surface of the yogurt packaging material from bottom to top and dried and cured at 60°C, and the first coating liquid is not coated.

[0207] Comparative Example 7

[0208] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this comparative example and Example 1 is that only the first coating liquid and the third coating liquid are sequentially coated on the surface of the yogurt packaging material from bottom to top and dried and cured at 60°C, and the second coating liquid is not coated.

[0209] Comparative Example 8

[0210] This comparative example provides a hydrophobic film and an anti-sticking yogurt packaging material. The difference between this comparative example and Example 1 is that only the first coating liquid, the second coating liquid and the third coating liquid are mixed and then coated on the surface of the yogurt packaging material and dried and solidified at 60°C.

[0211] Performance testing

[0212] Performance test (I)

[0213] The yogurts used in the performance test were all commercially available Yili Anmuxi Greek-flavored yogurt with batch number 20230219A12, and the production date was within 2 months.

[0214] The following testing methods were used to test the performance of the surface of the anti-stickiness yogurt packaging material with the hydrophobic film provided in each embodiment and each comparative example. The test results are shown in Table 3.

[0215] (1) Surface roughness: The surface roughness of the surface with the hydrophobic film of the anti-stick yogurt packaging material was tested according to the surface roughness measurement method provided in GB / T 31227-2014 (a method for evaluating the maximum peak-to-valley difference of the surface).

[0216] (2) Surface hydroxyl density: The hydroxyl groups on the surface of the hydrophobic film of the anti-sticking yogurt packaging material were detected using a Fourier transform infrared spectrometer, and the measured hydroxyl peak areas were integrated to obtain the surface hydroxyl density.

[0217] (3) Water contact angle: The water contact angle of the surface of the hydrophobic film of the anti-stick yogurt packaging material is tested using a contact angle tester; wherein the test temperature is 25°C ± 2°C.

[0218] (4) Yogurt contact angle: The yogurt contact angle of the surface of the anti-stick yogurt packaging material with a hydrophobic film is tested using a contact angle tester; wherein the test temperature is 25°C ± 2°C.

[0219] (5) Yogurt rolling angle: First, the anti-sticking yogurt packaging material in each embodiment and each comparative example is fixed on a flat plate, 0.2 mL of yogurt is dripped onto the surface with the hydrophobic film, and then the flat plate is slowly tilted until the yogurt rolls off. The tilt angle of the flat plate when the yogurt rolls off is the yogurt rolling angle; wherein the test temperature is 25°C ± 2°C.

[0220] Table 3

[0221]

[0222]

[0223] The test results in Table 3 show that the surface roughness, water contact angle and yogurt contact angle of the anti-sticking yogurt packaging material prepared by using the hydrophobic film provided by the present invention are 1.34 μm, 172° and 151° respectively, and the surface hydroxyl density and yogurt rolling angle are 5.4×10 3 Pieces / mm 2 and 10°, which improves the hydrophobicity of the yogurt packaging material and reduces the possibility of bonding between the yogurt packaging material and the yogurt, thereby improving the anti-adhesion effect of yogurt on the surface of the yogurt packaging material.

[0224] In Examples 1 to 3, the surface roughness, water contact angle, and yogurt contact angle of the anti-sticking yogurt packaging material provided in Example 2 were 1.34 μm, 172°, and 151°, respectively, and the surface hydroxyl density and yogurt rolling angle were 5.4×10 3 Pieces / mm 2 and 10°, indicating that the dosage of the modified nano-ferroferric oxide in the bottom layer of Example 2 is more appropriate, further improving the anti-adhesion effect of yogurt on the surface of the yogurt packaging material. The nano-ferroferric oxide is modified by micron silicon dioxide coating to form micron-scale hydrophobic synapses, which can cover more active groups on the surface of the substrate, such as hydroxyl, carboxyl, sulfonic acid, amide, ether bond, etc., which helps to prevent the adhesion of yogurt to the yogurt packaging material.

[0225] In Examples 4 to 7, the surface roughness, water contact angle and yogurt contact angle of the anti-sticking yogurt packaging materials provided in Examples 4 to 6 were 1.19-1.22 μm, 156-158° and 138-141°, respectively, and the surface hydroxyl density and yogurt rolling angle were (6.8-7.0)×10 3 Pieces / mm 2 and 19-21°, indicating that the modification method of the modified nano-ferroferric oxide in the bottom layer of Examples 4-6 is more suitable, and can further improve the yogurt anti-adhesion effect on the surface of the yogurt packaging material. Adjusting the amount of tetraethyl orthosilicate affects the modification effect of the modified nano-ferroferric oxide.

[0226] In Examples 8 to 11, the surface roughness, water contact angle and yogurt contact angle of the anti-sticking yogurt packaging materials provided in Examples 8 to 10 were 1.24-1.27 μm, 160-163° and 143-145°, respectively, and the surface hydroxyl density and yogurt rolling angle were (6.2-6.5)×10 3 Pieces / mm 2 and 16-18°, indicating that the dosage of tert-butyl isocyanate and wood pulp cellulose in the surface layer of Examples 8-10 is more appropriate, further improving the anti-adhesion effect of yogurt on the surface of the yogurt packaging material. Wood pulp cellulose can improve the stability of tert-butyl isocyanate.

[0227] In Examples 12 to 16, the surface roughness, water contact angle and yogurt contact angle of the anti-sticking yogurt packaging materials provided in Examples 13 to 15 were 1.30-1.32 μm, 166-168° and 146-148°, respectively, and the surface hydroxyl density and yogurt rolling angle were (5.7-5.9)×10 3 Pieces / mm 2 and 12-13°, indicating that the weight ratio of calcium stearate to tristearin in the surface layer of Examples 13 to 15 is more suitable to be 1:2-3, which further improves the anti-adhesion effect of yogurt on the surface of the yogurt packaging material. Adjusting the weight ratio of calcium stearate to tristearin can further improve the dispersion uniformity of calcium stearate in the surface layer.

[0228] In Examples 17 to 19, the surface roughness, water contact angle, and yogurt contact angle of the anti-sticking yogurt packaging material provided in Example 18 were 1.34 μm, 172°, and 151°, respectively, and the surface hydroxyl density and yogurt rolling angle were 5.4×10 3 Pieces / mm 2 and 10°, indicating that the dosage of the fatty alcohol polyoxyethylene ether in the surface layer of Example 18 is more appropriate, further improving the yogurt anti-adhesion effect on the surface of the yogurt packaging material.

[0229] In addition, combining the various index data of the anti-sticking yogurt packaging materials of Example 1 to Example 3 and Example 1, it is found that the addition of modified nano-ferroferric oxide and beeswax to the bottom raw materials of the present invention can improve the anti-sticking effect of yogurt on the surface of the yogurt packaging material to varying degrees.

[0230] Performance test (II)

[0231] The following testing methods were used to test the performance of the surfaces of the anti-stickiness yogurt packaging materials with the hydrophobic film provided in Example 1, Example 18 and Comparative Examples 1 to 8, respectively. The test results are shown in Table 4.

[0232] (1) Hardness: Cut a 60 mm wide and 70 mm long anti-stick yogurt packaging material as a sample. Gently place a pencil hardness tester on the surface of the sample with the hydrophobic film. Push forward 10 mm at a speed of 5-0 cm / s. Observe the surface of the sample with the naked eye to see if it is scratched. Test step by step from hard to soft in the order of pencil hardness until the coating film is completely unscratched by the pencil tip. Record the pencil hardness of the sample.

[0233] (2) Abrasion resistance test: A 60 mm wide and 70 mm long anti-sticking yogurt packaging material was cut as a sample, and a 500 g weight was used, which was covered with a microfiber cloth. The sample was subjected to an abrasion resistance test on the surface of the sample with the hydrophobic film 100 times back and forth. After the friction, 0.2 mL of yogurt was dropped into the sample and the sample was tilted horizontally. If the sample rolled down completely, it was qualified. If the sample did not roll down even if the sample was tilted 90°, it was unqualified.

[0234] Table 4

[0235] Pencil hardness Wear test Example 1 HB qualified Embodiment 18 H qualified Comparative Example 1 HB Failure Comparative Example 2 HB qualified Comparative Example 3 HB qualified Comparative Example 4 HB qualified Comparative Example 5 HB qualified Comparative Example 6 HB Failure Comparative Example 7 HB qualified Comparative Example 8 HB qualified

[0236] The test results in Table 4 show that the anti-sticking yogurt packaging material prepared by using the hydrophobic film provided by the present invention has a hardness of one side with the coating film between HB and H, and is qualified after the wear resistance test, having high hardness and wear resistance.

[0237] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A hydrophobic membrane, wherein: The hydrophobic membrane comprises a bottom layer, a middle layer and a surface layer; wherein, The raw material components of the bottom layer include: 15-35 parts by weight of high molecular weight polyethylene, 20-40 parts by weight of modified nano ferroferric oxide, and 20-30 parts by weight of beeswax; wherein the modified nano ferroferric oxide is micron silicon dioxide coated nano ferroferric oxide; the weight average molecular weight of the high molecular weight polyethylene is more than 100,000; The raw material components of the middle layer include: 5-10 parts by weight of polydimethylsiloxane, 5-15 parts by weight of nano silicon dioxide and 1-5 parts by weight of silane; The raw material components of the surface layer include: 5-10 parts by weight of tert-butyl isocyanate and 0.3-0.5 parts by weight of wood pulp cellulose.

2. The hydrophobic membrane according to claim 1, wherein The modified nano-ferroferric oxide can be prepared by the following method: Mixing nano-ferroferric oxide with anhydrous ethanol and ethyl orthosilicate, adding ammonia water at 40-50° C., stirring, filtering, drying and crushing to obtain the modified nano-ferroferric oxide; Preferably, the weight ratio of ferrosoferric oxide to ethyl orthosilicate is 1-3:5-10; Preferably, the usage ratio of ferrosoferric oxide to anhydrous ethanol is 1-3kg:5-10L; Preferably, the mass concentration of the ammonia water is 20-30%, and the usage ratio of the ammonia water to ferrosoferric oxide is 1-3kg:40-60mL.

3. The hydrophobic membrane according to claim 1, wherein The raw material component silane of the middle layer includes one or a combination of two or more of trimethylmethoxysilane, trimethylethoxysilane, trimethylchlorosilane, triethylmethoxysilane, triethylethoxysilane, and triethylchlorosilane.

4. The hydrophobic membrane according to claim 1, wherein The raw material components of the surface layer further include 5-10 parts by weight of calcium stearate and 10-20 parts by weight of glyceryl tristearate.

5. The hydrophobic membrane according to claim 4, wherein The weight ratio of the calcium stearate to the glyceryl tristearate is 1:2-3.

6. The hydrophobic membrane according to claim 1, wherein The raw material components of the surface layer further include 1-3 parts by weight of fatty alcohol polyoxyethylene ether.

7. The hydrophobic film coating liquid according to any one of claims 1 to 6, wherein The coating liquid for the hydrophobic film comprises a first coating liquid, a second coating liquid and a third coating liquid which are stored separately; The first coating liquid comprises a mixture of raw material components of the bottom layer of the hydrophobic film according to any one of claims 1 to 6 and a solvent; The second coating liquid comprises a mixture of raw material components of the middle layer of the hydrophobic film according to any one of claims 1 to 6 and a solvent; The third coating liquid comprises a mixture of raw material components of the surface layer of the hydrophobic film according to any one of claims 1 to 6 and a solvent; Wherein, in the first coating solution, the weight ratio of the total mass of the raw material components of the bottom layer of the hydrophobic film to the solvent is 1:1-25; Wherein, in the second coating solution, the weight ratio of the total mass of the raw material components of the middle layer of the hydrophobic film to the solvent is 1:1-25; Wherein, in the third coating solution, the weight ratio of the total mass of the raw material components of the surface layer of the hydrophobic film to the solvent is 1:1-25; Preferably, the raw material component solvent of the first coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol; Preferably, the raw material component solvent of the second coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol; Preferably, the raw material component solvent of the third coating solution includes one or a combination of two or more of ethyl acetate, ethanol, acetone and butanol.

8. The method for preparing a hydrophobic membrane according to any one of claims 1 to 6, wherein: The method includes: The first coating liquid, the second coating liquid and the third coating liquid in the hydrophobic film coating liquid of claim 7 are sequentially coated on the surface of the substrate from bottom to top and cured to obtain the hydrophobic film.

9. Use of the hydrophobic film according to any one of claims 1 to 6 in yogurt packaging materials.

10. A non-stick yogurt packaging material, wherein: The surface of the anti-sticking yogurt packaging material is coated with the hydrophobic film according to any one of claims 1 to 6; Preferably, the yogurt packaging material comprises one or a combination of two or more of PE, LLDPE, LDPE, HDPE, EVA, and modified EVA.

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