Production method of high-end filter aluminum foil for coating

Abstract

The invention relates to a production method of a high-end filter aluminum foil for a coating, which comprises the following steps: (1) stirring and mixing polymethylene polyphenyl isocyanate, polyol, a polymerization inhibitor, a catalyst and water, and reacting to obtain a prepolymer; (2) mixing the prepolymer with polysorbate and cyclopentane to obtain a base coating; (3) the surface of the aluminum foil is coated with the base layer paint, and the aluminum foil coated with a base layer coating is obtained; (4) adding a surfactant into water, uniformly mixing, adding silicate, a boron compound and nano silicon dioxide, and uniformly stirring to obtain a hydrophilic coating; and (5) the surface of the base layer coating is coated with hydrophilic paint, and the coating aluminum foil is obtained. The base layer coating is of a porous structure, the roughness of the surface of the aluminum foil is improved, the hydrophilicity of the hydrophilic coating is improved to a certain extent through the roughness of the porous structure in the base layer coating, and the hydrophilic angle of the hydrophilic coating is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum foil production, and in particular to a method for producing high-end filter aluminum foil for coating. Background Art

[0002] Aluminum is widely used because of its advantages such as low density, good thermal conductivity, easy processing, odorless and environmental protection. Among them, coated aluminum foil is a process product obtained by coating one or more layers of materials on the surface of aluminum foil with special treatment. Aluminum foil used for filters is often coated aluminum foil. When the aluminum foil used for filters encounters high temperature and other environments, grease is easily attached to the surface of the coated aluminum foil, which is not conducive to the cleaning of stains on the surface of the aluminum foil. Therefore, the coating coated on the surface of the aluminum foil used for filters is often a hydrophilic coating to improve the decontamination ability of the aluminum foil. For example, Chinese patent CN114106604B discloses a coated aluminum foil and its preparation method and application. The coated aluminum foil includes a hydrophilic layer and an anti-corrosion layer. The performance of the hydrophilic layer is stable, and the performance decay is small after long-term operation. However, the improvement of the hydrophilicity of the aluminum foil is limited, which leads to its weak decontamination ability and self-cleaning power. Summary of the invention

[0003] The present invention provides a method for producing a high-end filter aluminum foil for coating to solve the above problems.

[0004] The technical solution adopted by the present invention is: a method for producing a high-end filter aluminum foil for coating, the method at least comprising the following steps: (1) Mixing polymethylene polyphenyl isocyanate, polyol, polymerization inhibitor, catalyst and water by stirring and reacting to obtain a prepolymer; (2) mixing the prepolymer with polysorbate and cyclopentane to obtain a base coating; (3) coating the base coating on the surface of the aluminum foil to obtain an aluminum foil coated with the base coating after reaction; (4) Add the surfactant to water, mix well, then add silicate, boron compound, and nano-silicon dioxide, stir well, and the hydrophilic coating is obtained; (5) A hydrophilic coating is coated on the surface of the base coating to obtain an aluminum foil containing a functional coating.

[0005] Preferably, the polyol is a mixture of polyether polyol, polyester polyol and castor oil, and the mass ratio of polyether polyol, polyester polyol and castor oil is 1:(0.5-1.5):(0.4-0.6), the average molecular weight of the polyol is 3500-10000 g / mol, and the molar ratio of the polyol to polymethylene polyphenyl isocyanate is 1:(2-3).

[0006] Preferably, the catalyst comprises 2 parts of 33% triethylenediamine, 0.2 parts of dibutyltin dilaurate, 1 part of bis(dimethylaminoethyl)ether, the total weight of polymethylene polyphenyl isocyanate and polyol is 100 parts, the total amount of catalyst is 3.2 parts, the amount of inhibitor is 0.5-1 parts, the amount of water is 0.5-2 parts, and the mass ratio of polysorbate to cyclopentane and prepolymer is (1-4):(5-10):100.

[0007] Preferably, the surfactant is at least one of sodium dodecyl sulfonate, sodium dodecyl sulfate and potassium dodecyl sulfate, and the mass ratio of water, surfactant, silicate, boron compound and nano-silicon dioxide is: 50:(0.5-2):(10-15):(1-3):(0.5-1).

[0008] Preferably, the mesh plate is placed on the surface of the base coating in step (3) for 5-10 seconds, and mist water droplets are sprayed on the surface of the base coating. The obtained aluminum foil coated with the base coating is then placed in a drying room at 40-55° C. for 5-8 hours, and then the hydrophilic coating is sprayed on the surface of the base coating in a dot pattern.

[0009] Preferably, the silicate is at least one of potassium silicate, sodium silicate and aluminum silicate, and the boron compound is one of sodium borate, boric acid, sodium tetraborate and potassium tetraborate.

[0010] Preferably, the nano-silica is hydroxylated nano-silica, and carboxylic acid monomer, N-(hydroxymethyl)acrylamide and benzenesulfonic acid are further added in step (4), and the mass ratio of carboxylic acid monomer, N-(hydroxymethyl)acrylamide, benzenesulfonic acid to hydroxylated nano-silica is 1:2.5:(0.05-0.1):(0.8-1.2).

[0011] Preferably, the specific reaction process of step (4) is: adding a surfactant to water, mixing evenly, then adding hydroxylated nano-silica, carboxyl acrylic acid monomer, N-(hydroxymethyl) acrylamide, benzenesulfonic acid, stirring evenly, and reacting at 60-80° C. for 6-12 hours, and then adding silicate and boron compound after the reaction, stirring evenly, to obtain a hydrophilic coating.

[0012] Preferably, in step (3), before coating, the surface of the aluminum foil is cleaned, dried and pretreated, and the pretreatment is to treat the surface of the aluminum foil substrate with plasma, corona or microwave.

[0013] Compared with the prior art, the present invention has the following advantages: (1) By coating the base coating on the surface of the aluminum foil, on the one hand, it is easy to improve the bonding performance between the hydrophilic coating and the aluminum foil. At the same time, the base coating is a porous structure, which increases the roughness of the aluminum foil surface and further enhances the adhesion of the hydrophilic coating. The roughness of the porous structure inside the base coating also improves the hydrophilic performance of the hydrophilic coating to a certain extent and reduces its hydrophilic angle. (2) During use, moisture will be stored in the porous structure of the base coating through the hydrophilic coating, so that the base coating can store a certain amount of moisture. After the moisture is released, it adheres to the surface of the hydrophilic coating, improving the cleaning ability of the hydrophilic coating and further improving its hydrophilicity, thereby extending the self-cleaning cycle of the aluminum foil. (3) DETAILED DESCRIPTION

[0014] In order to better illustrate the present invention, it is further described in conjunction with examples.

[0015] A method for producing a high-end filter aluminum foil for coating, the method comprising the following steps: (1) Mixing polymethylene polyphenyl isocyanate, polyol, polymerization inhibitor, catalyst and water by stirring and reacting to obtain a prepolymer; the total weight of polymethylene polyphenyl isocyanate and polyol is 100 parts, the total amount of catalyst is 3.2 parts, the amount of polymerization inhibitor is 0.5-1 part, the amount of water is 0.5-2 parts, the polyol is a mixture of polyether polyol, polyester polyol and castor oil, and the mass ratio of polyether polyol, polyester polyol and castor oil is 1:(0.5-1.5):(0.4-0.6), the average molecular weight of the polyol is 3500-10000 g / mol, and the molar ratio of the polyol to polymethylene polyphenyl isocyanate is 1:(2-3); the catalyst comprises 2 parts of 33% triethylenediamine, 0.2 parts of dibutyltin dilaurate and 1 part of bis(dimethylaminoethyl)ether.

[0016] (2) The prepolymer is mixed with polysorbate and cyclopentane to obtain a base coating; the mass ratio of polysorbate to cyclopentane and prepolymer is (1-4):(5-10):100, wherein the polysorbate is a mixture of Tween 60 and Tween 80, and the mass ratio of Tween 60 to Tween 80 is 4:6.

[0017] (3) The surface of the aluminum foil is cleaned, dried and pretreated, wherein the pretreatment is to treat the surface of the aluminum foil substrate with plasma, corona or microwave. The base coating is coated on the pretreated surface of the aluminum foil, and after reaction, an aluminum foil coated with the base coating is obtained, and the thickness of the base coating is 3-100 μm; a mesh plate is placed on the surface of the base coating for 5-10 seconds, and then the obtained aluminum foil coated with the base coating is placed in a drying room at 40-55°C for 5-8 hours, and then a hydrophilic coating is sprayed on the surface of the base coating in a dotted manner; (4) Add 0.5-1 part of surfactant to 50 parts of water, mix well, then add 0.5-1 part of hydroxylated nano-silica, 2.5 parts of carboxyl acrylic acid monomer, 1 part of N-(hydroxymethyl) acrylamide, 0.05-0.1 part of benzene sulfonic acid, stir well, and react at 60-80°C for 6-12 hours. After the reaction, add 10-15 parts of silicate and 1-3 parts of boron compound, stir well, and the hydrophilic coating is obtained. The surfactant is at least one of sodium dodecyl sulfonate, sodium dodecyl sulfate, and potassium dodecyl sulfate, the silicate is at least one of potassium silicate, sodium silicate, and aluminum silicate, and the boron compound is one of sodium borate, boric acid, sodium tetraborate, and potassium tetraborate.

[0018] (5) Coating a hydrophilic coating on the surface of the base coating to obtain an aluminum foil containing a functional coating, wherein the thickness of the hydrophilic coating is ≥8 μm.

[0019] Example 1 A method for producing a high-end filter aluminum foil for coating, the method comprising the following steps: (1) Mixing polymethylene polyphenyl isocyanate, polyol, polymerization inhibitor, catalyst and water by stirring and reacting to obtain a prepolymer; the total weight of polymethylene polyphenyl isocyanate and polyol is 100 parts, the molar ratio of polyol to polymethylene polyphenyl isocyanate is 1:2, the polyol is a mixture of polyether polyol, polyester polyol and castor oil, and the mass ratio of polyether polyol, polyester polyol and castor oil is 1:0.5:0.5, the average molecular weight of the polyol is 3500 g / mol, the catalyst comprises 2 parts of 33% triethylenediamine, 0.2 parts of dibutyltin dilaurate and 1 part of bis(dimethylaminoethyl)ether, the amount of polymerization inhibitor is 0.5 parts, and the amount of water is 0.5 parts; (2) 100 parts of the prepolymer are mixed with 0.4 parts of Tween 40, 0.6 parts of Tween 80 and 5 parts of cyclopentane to obtain a base coating; (3) The surface of the aluminum foil is cleaned, dried and pretreated, and the pretreatment is to treat the surface of the aluminum foil substrate with plasma, corona or microwave. The base coating is coated on the pretreated surface of the aluminum foil, and after reaction, an aluminum foil coated with a base coating is obtained, and the thickness of the base coating is 3μm; a mesh plate is placed on the surface of the base coating for 5s, and mist water droplets are sprayed on the surface of the base coating. Then, the obtained aluminum foil coated with the base coating is placed in a drying room at 40°C for 5h, and then a hydrophilic coating is sprayed on the surface of the base coating in a dotted manner; (4) Add 0.5 parts of sodium dodecyl sulfate to 50 parts of water and mix well. Then add 0.5 parts of hydroxylated nano-silica, 2.5 parts of carboxyl acrylic acid monomer, 1 part of N-(hydroxymethyl) acrylamide and 0.05 parts of benzenesulfonic acid. Stir well and react at 60°C for 6 hours. After reaction, add 10 parts of potassium silicate and 1 part of sodium borate and stir well to obtain a hydrophilic coating.

[0020] (5) A hydrophilic coating is coated on the surface of the base coating to obtain an aluminum foil containing a functional coating, and the thickness of the hydrophilic coating is 10 μm.

[0021] Example 2 A method for producing a high-end filter aluminum foil for coating, the method comprising the following steps: (1) Mixing polymethylene polyphenyl isocyanate, polyol, polymerization inhibitor, catalyst and water by stirring and reacting to obtain a prepolymer; the total weight of polymethylene polyphenyl isocyanate and polyol is 100 parts, the catalyst comprises 2 parts of 33% triethylene diamine, 0.2 parts of dibutyltin dilaurate and 1 part of bis(dimethylaminoethyl)ether, the dosage of the polymerization inhibitor is 0.8 parts, the dosage of water is 1.5 parts, the polyol is a mixture of polyether polyol, polyester polyol and castor oil, and the mass ratio of polyether polyol, polyester polyol and castor oil is 1:1.0:0.5, the average molecular weight of the polyol is 8000 g / mol, and the molar ratio of the polyol to polymethylene polyphenyl isocyanate is 1:2.5.

[0022] (2) 100 parts of the prepolymer were mixed with 0.8 parts of Tween 60, 1.2 parts of Tween 80 and 8 parts of cyclopentane to obtain a base coating.

[0023] (3) The surface of the aluminum foil is cleaned, dried and pretreated, and the pretreatment is to treat the surface of the aluminum foil substrate with plasma, corona or microwave. The base coating is coated on the pretreated surface of the aluminum foil, and after reaction, an aluminum foil coated with a base coating is obtained, and the thickness of the base coating is 50μm; a mesh plate is placed on the surface of the base coating for 8s, and mist water droplets are sprayed on the surface of the base coating. Then, the obtained aluminum foil coated with the base coating is placed in a drying room at 50°C for 6h, and then a hydrophilic coating is sprayed on the surface of the base coating in a dotted manner; (4) Add 0.8 parts of sodium dodecyl sulfate to 50 parts of water and mix well. Then add 0.8 parts of hydroxylated nano-silica, 2.5 parts of carboxyl acrylic acid monomer, 1 part of N-(hydroxymethyl) acrylamide and 0.08 parts of benzenesulfonic acid. Stir well and react at 70°C for 10 hours. After reaction, add 12 parts of sodium silicate and 2 parts of boric acid and stir well to obtain a hydrophilic coating.

[0024] (5) Coating a hydrophilic coating on the surface of the base coating to obtain an aluminum foil containing a functional coating, wherein the thickness of the hydrophilic coating is ≥8 μm.

[0025] Example 3 A method for producing a high-end filter aluminum foil for coating, the method comprising the following steps: (1) Mixing polymethylene polyphenyl isocyanate, polyol, polymerization inhibitor, catalyst and water by stirring and reacting to obtain a prepolymer; the total weight of polymethylene polyphenyl isocyanate and polyol is 100 parts, the polyol is a mixture of polyether polyol, polyester polyol and castor oil, and the mass ratio of polyether polyol, polyester polyol and castor oil is 1:1.5:0.6, the average molecular weight of the polyol is 10000 g / mol, and the molar ratio of the polyol to polymethylene polyphenyl isocyanate is 1:3; the amount of polymerization inhibitor is 1 part, the amount of water is 2 parts, and the catalyst includes 2 parts of 33% triethylenediamine, 0.2 parts of dibutyltin dilaurate and 1 part of bis(dimethylaminoethyl)ether.

[0026] (2) 100 parts of the prepolymer are mixed with 1.6 parts of Tween 60, 2.4 parts of Tween 80 and 10 parts of cyclopentane to obtain a base coating; (3) The surface of the aluminum foil is cleaned, dried and pretreated, and the pretreatment is to treat the surface of the aluminum foil substrate with plasma, corona or microwave. The base coating is coated on the pretreated surface of the aluminum foil, and after reaction, an aluminum foil coated with a base coating is obtained, and the thickness of the base coating is 100 μm; a mesh plate is placed on the surface of the base coating for 10 seconds, and mist water droplets are sprayed on the surface of the base coating. Then, the obtained aluminum foil coated with the base coating is placed in a drying room at 55°C for 8 hours, and then a hydrophilic coating is sprayed on the surface of the base coating in a dotted manner; (4) Add 0.5 parts of potassium dodecyl sulfate and 0.5 parts of sodium dodecyl sulfonate to 50 parts of water, mix well, then add 0.5-1 parts of hydroxylated nano-silica, 2.5 parts of carboxyl acrylic acid monomer, 1 part of N-(hydroxymethyl) acrylamide, 0.05-0.1 parts of benzenesulfonic acid, stir well and react at 60-80°C for 6-12 hours. After the reaction, add 5 parts of potassium silicate, 5 parts of sodium silicate, 5 parts of aluminum silicate, 1 part of potassium tetraborate, 1 part of sodium tetraborate, and 1 part of sodium borate, stir well to obtain a hydrophilic coating.

[0027] (5) Coating a hydrophilic coating on the surface of the base coating to obtain an aluminum foil containing a functional coating, wherein the thickness of the hydrophilic coating is ≥8 μm.

[0028] In Comparative Example 1, no mesh plate was placed on the surface of the base coating; In Comparative Example 2, no base coating was applied; In Comparative Example 3, no hydroxylated nano-silica was added; In Comparative Example 4, no silicate was added.

[0029] The aluminum foils prepared in Examples 1-3 were baked at 60°C for 30 minutes, then heated to 120°C for 20 minutes, and the performance of the coatings was tested. The results are shown in Table 1. In addition, the obtained aluminum foils were placed in a simulated filter environment, and the hot steam generated by the blending oil heated to 280°C was directly applied to the surface of the aluminum foil. The hydrophilic angle of the coating on the surface of the aluminum foil and the weight of the residual oil on the surface of the aluminum foil were tested after different time periods.

[0030] Table 1 The above-described embodiments are only preferred embodiments of the present invention. It should be noted that those skilled in the art may make several changes and improvements without departing from the overall concept of the present invention, and these should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for producing high-end filter aluminum foil for coating, characterized in that: The method comprises at least the following steps: (1) Mixing polymethylene polyphenyl isocyanate, polyol, polymerization inhibitor, catalyst and water by stirring and reacting to obtain a prepolymer; (2) mixing the prepolymer with polysorbate and cyclopentane to obtain a base coating; (3) coating the base coating on the surface of the aluminum foil to obtain an aluminum foil coated with the base coating after reaction; (4) Add the surfactant to water, mix well, then add silicate, boron compound, and nano-silicon dioxide, stir well, and the hydrophilic coating is obtained; (5) A hydrophilic coating is coated on the surface of the base coating to obtain an aluminum foil containing a functional coating.

2. The method for producing a high-end filter aluminum foil for coating according to claim 1, characterized in that: The polyol is a mixture of polyether polyol, polyester polyol and castor oil, and the mass ratio of polyether polyol, polyester polyol and castor oil is 1:(0.5-1.5):(0.4-0.6), the average molecular weight of the polyol is 3500-10000 g / mol, and the molar ratio of the polyol to polymethylene polyphenyl isocyanate is 1:(2-3).

3. The method for producing a high-end filter aluminum foil for coating according to claim 2, characterized in that: The catalyst comprises 2 parts of 33% triethylenediamine, 0.2 parts of dibutyltin dilaurate, 1 part of bis(dimethylaminoethyl)ether, the total weight of polymethylene polyphenyl isocyanate and polyol is 100 parts, the total amount of the catalyst is 3.2 parts, the amount of the inhibitor is 0.5-1 parts, the amount of water is 0.5-2 parts, and the mass ratio of polysorbate to cyclopentane and prepolymer is (1-4):(5-10):

100.

4. The method for producing a high-end filter aluminum foil for coating according to claim 1, characterized in that: The surfactant is at least one of sodium dodecyl sulfonate, sodium dodecyl sulfate and potassium dodecyl sulfate, and the mass ratio of water, surfactant, silicate, boron compound and nano silicon dioxide is 50:(0.5-2):(10-15):(1-3):(0.5-1).

5. The method for producing a high-end filter aluminum foil for coating according to claim 4, characterized in that: The mesh plate is placed on the surface of the base coating in step (3) for 5-10 seconds, and mist water droplets are sprayed on the surface of the base coating. The obtained aluminum foil coated with the base coating is then placed in a drying room at 40-55°C for 5-8 hours. Next, a hydrophilic coating is sprayed on the surface of the base coating in a dot pattern.

6. The method for producing a high-end filter aluminum foil for coating according to claim 5, characterized in that: The silicate is at least one of potassium silicate, sodium silicate and aluminum silicate, and the boron compound is one of sodium borate, boric acid, sodium tetraborate and potassium tetraborate.

7. The method for producing a high-end filter aluminum foil for coating according to claim 6, characterized in that: The nano-silica is hydroxylated nano-silica. In step (4), carboxylic acid monomer, N-(hydroxymethyl)acrylamide and benzenesulfonic acid are further added. The mass ratio of carboxylic acid monomer, N-(hydroxymethyl)acrylamide, benzenesulfonic acid and hydroxylated nano-silica is 1:2.5:(0.05-0.1):(0.8-1.2).

8. The method for producing a high-end filter aluminum foil for coating according to claim 7, characterized in that: The specific reaction process of step (4) is as follows: add the surfactant into water, mix well, then add hydroxylated nano-silica, carboxyl acrylic acid monomer, N-(hydroxymethyl) acrylamide, benzenesulfonic acid, stir well, and react at 60-80° C. for 6-12 hours. After the reaction, add silicate and boron compound, stir well, and obtain a hydrophilic coating.

9. The method for producing a high-end filter aluminum foil for coating according to claim 1, characterized in that: In step (3), before coating, the surface of the aluminum foil is cleaned, dried and pretreated, and the pretreatment is to treat the surface of the aluminum foil substrate with plasma, corona or microwave.

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