Moisture absorption coating, preparation method and moisture absorption aluminum foil

Abstract

The invention relates to the field of aluminum foil material processing, and particularly discloses a moisture absorption coating, a preparation method and a moisture absorption aluminum foil. The moisture absorption coating is prepared from 20-30 parts of acrylic resin, 36-72 parts of water, 1-10 parts of ethanol, 1-10 parts of isopropanol, 1-5 parts of polycarbonate coated moisture absorption filler, 1-3 parts of polycarbonate coated fiber, 1-2 parts of a dispersing agent, 1-2 parts of a defoaming agent, 1-2 parts of a thickening agent and 2-4 parts of a curing agent. The preparation method comprises the following steps: weighing acrylic resin, part of water, ethanol and isopropanol, uniformly mixing, heating for reaction, then cooling, adding the polycarbonate coated moisture absorption filler and the fiber material carrying polyvinyl alcohol, uniformly mixing, adding the dispersing agent, the defoaming agent and the thickening agent, and uniformly mixing to obtain a mixture A; uniformly mixing the curing agent and the residual water to obtain a mixture B; uniformly mixing the mixture A and the mixture B to obtain a moisture absorption coating; preparing moisture-absorbing aluminum foil from the moisture-absorbing coating; the coating on the moisture-absorbing aluminum foil can absorb water vapor in the medicine and keep the medicine dry.

Description

Technical Field

[0001] The present application relates to the field of aluminum foil material processing, and more specifically, to a hygroscopic coating, a preparation method and hygroscopic aluminum foil. Background Art

[0002] Medicinal aluminum foil is an aluminum foil layer used to package tablets. It is mainly made of aluminum foil and plastic. It has the advantages of moisture-proof and anti-oxidation. It protects the drugs from deterioration and shelf life. It also has good protective effects. During the transportation of drugs, it is not easy to affect the integrity and quality of the drugs due to external impact, extrusion and other problems.

[0003] After the medicines are packaged, the high humidity in the external environment causes water vapor to slowly penetrate the composite aluminum foil, causing the medicines in the composite aluminum foil package to become damp. Therefore, it is necessary to prepare a new coating so that after it forms a coating on the surface of the aluminum foil, the coating has a hygroscopic effect. On the side of the composite aluminum foil close to the medicine, it can reversely absorb the water vapor in the medicine to keep the medicine dry. However, after the coating absorbs moisture, it is easy to affect the bonding stability of the coating on the surface of the aluminum foil.

[0004] Therefore, there is an urgent need to prepare a new hygroscopic coating that can stably adhere to the side of the composite aluminum foil close to the medicine, and the coating formed after the coating is cured can reversely absorb water vapor in the medicine to keep the medicine dry; at the same time, the coating can still stably adhere to the surface of the aluminum foil after absorbing moisture. Summary of the invention

[0005] In order to prepare a new hygroscopic coating, which can stably adhere to the side of the composite aluminum foil close to the medicine, and the coating formed after the coating is cured can reversely absorb water vapor in the medicine to keep the medicine dry; at the same time, the coating can still stably adhere to the surface of the aluminum foil after absorbing moisture, the application provides a hygroscopic coating, a preparation method and a hygroscopic aluminum foil.

[0006] In the first aspect, the present application provides a hygroscopic coating, which adopts the following technical solution: A hygroscopic coating comprises the following raw materials in parts by weight: 20-30 parts of acrylic resin, 36-72 parts of water, 1-10 parts of ethanol, 1-10 parts of isopropanol, 1-5 parts of polycarbonate coated hygroscopic filler, 1-3 parts of polycarbonate coated fiber, 1-2 parts of dispersant, 1-2 parts of defoamer, 1-2 parts of thickener and 2-4 parts of curing agent.

[0007] By adopting the above technical scheme, the acrylic resin has good fluidity under the action of water, ethanol and isopropanol, which is convenient for uniform coating on the surface of aluminum foil; the polycarbonate coated hygroscopic filler and polycarbonate coated fiber are used to prevent the hygroscopic filler and fiber from excessively absorbing moisture in the coating during the storage process of the coating and before being coated on the surface of aluminum foil before the coating is heated and cured, thereby affecting the subsequent absorption of water vapor in the medicine by the hygroscopic filler and fiber, thereby affecting the drying effect of the medicine; and the absorption of moisture in the hygroscopic coating by the hygroscopic filler and fiber is also likely to affect the viscosity of the hygroscopic coating, thereby affecting the dispersion uniformity of the polycarbonate coated hygroscopic filler and polycarbonate coated fiber on the surface of aluminum foil, resulting in the uniform drying effect of the medicine being affected; the thickener is used to enable the hygroscopic coating to stably adhere to the side of the composite aluminum foil close to the medicine.

[0008] During the temperature rise and curing process of the hygroscopic coating, polycarbonate is hot-melted and dispersed, releasing hygroscopic fillers and fibers. After the hygroscopic coating is cured to form a coating, the hygroscopic fillers and fibers can absorb excess water vapor on one side of the drug to keep the drug dry. During and after the hygroscopic process, polycarbonate exists around the hygroscopic fillers and fibers. By utilizing the moisture barrier effect of polycarbonate, the coating formed by the coating can still stably adhere to the surface of the aluminum foil after absorbing moisture, and the coating is not prone to peeling or stratification, thereby ensuring the bonding stability of the coating on the aluminum foil surface.

[0009] Preferably, the polycarbonate coated hygroscopic filler is prepared from a hygroscopic filler, an ammonium bicarbonate solution, a polycarbonate melt, and a silicon dioxide whisker in a mass ratio of 1:1-2:0.5-1:0.1-0.5.

[0010] By adopting the above technical scheme, after the hygroscopic filler absorbs the ammonium bicarbonate solution, the ammonium bicarbonate is dispersed in the pores of the hygroscopic filler, and then the surface is loaded with a polycarbonate melt. The adhesiveness of the polycarbonate melt is utilized to adhere the silica whiskers to the surface of the hygroscopic filler; a binding network is constructed with the silica whiskers to form a binding structure around the hygroscopic filler, thereby preventing the hygroscopic filler from expanding after absorbing moisture and affecting the stability of the internal structure of the coating.

[0011] During the coating curing process, the polycarbonate is hot-melted, and the silica whiskers can guide the polycarbonate, and release the gas by heating with ammonium bicarbonate, ensuring that the pores of the hygroscopic filler are connected to the external environment, ensuring that the coating on the surface of the aluminum foil can absorb excess water vapor on one side of the drug, and ensuring the drying effect of the drug.

[0012] Preferably, the hygroscopic filler is made of molecular sieve and silica gel particles in a mass ratio of 1:0.2-0.5.

[0013] By adopting the above technical solution, both the molecular sieve and the silica gel particles have a porous effect and can adsorb ammonium bicarbonate. After the ammonium bicarbonate releases gas, the pores of the molecular sieve and the silica gel particles can be connected with the external environment over a large area. Combined with the hygroscopic effect of the molecular sieve and the silica gel particles, the excess water vapor on one side of the drug can be further absorbed to ensure the drying effect of the drug.

[0014] Molecular sieves and silica gel particles are not prone to excessive expansion after absorbing moisture. Combined with the network blockade of polycarbonate and silica whiskers, the molecular sieves and silica gel particles are further prevented from expanding, ensuring that the coating formed by the hygroscopic coating on the aluminum foil surface has high adhesion stability.

[0015] After the molecular sieve and silica gel particles absorb moisture, it is not easy for moisture to disperse and circulate inside the coating. Combined with the barrier effect of polycarbonate and silica, it further prevents moisture from migrating to other locations in the acrylic resin coating, ensuring that the coating still has a high adhesion stability on the aluminum foil surface after absorbing moisture.

[0016] Molecular sieves and silica gel particles have a large specific surface area. Together with the binding network of polycarbonate and silica whiskers, the surface area of ​​the polycarbonate coated hygroscopic filler is further increased. After contacting with acrylic resin, the dispersion stability of the polycarbonate coated hygroscopic filler in the acrylic resin coating can be improved. During the coating curing process, the connection between polycarbonate and acrylic resin further improves the bonding stability of the molecular sieve and silica gel particles on the coating surface, ensuring that the hygroscopic coating is stably attached to the aluminum foil surface.

[0017] Preferably, the silica whiskers are prepared from porous silica whiskers by reacting with silane coupling agent KH-570, and the average porosity of the silica whiskers is 10-15%.

[0018] By adopting the above technical scheme, after the surface of the porous silica whisker is treated with the silane coupling agent KH-570, the porous silica has a hydrophobic effect, and the existence of the pore structure can ensure the flow of gas, ensure the absorption of excess moisture on one side of the drug by the hygroscopic coating, and ensure the drying effect of the drug; at the same time, the silane coupling agent can improve the cross-linking effect of the silica whisker and the acrylic resin, thereby improving the hygroscopic coating formed by the hygroscopic coating has higher strength and stability, and can stably adhere to the surface of the aluminum foil.

[0019] Preferably, the polycarbonate coated fiber is made of cellulose fiber, polyvinyl alcohol particles and polycarbonate melt in a mass ratio of 1:0.1-0.3:0.5-1.

[0020] By adopting the above technical scheme, cellulose fibers, polyvinyl alcohol particles and polycarbonate are matched, and the bonding effect of the polycarbonate melt is utilized to facilitate the adhesion of the polyvinyl alcohol particles to the surface of the cellulose fibers, and the outer surface is the polycarbonate melt; in the process of applying the hygroscopic coating to the surface of the aluminum foil, the barrier effect of polycarbonate is utilized to prevent the polyvinyl alcohol and cellulose fibers from absorbing moisture in the coating, thereby ensuring that the cellulose fibers and polyvinyl alcohol particles can absorb excess moisture on one side of the drug, ensuring the drug drying effect, and ensuring the uniformity of coating.

[0021] During the curing process of the hygroscopic coating, as the curing temperature rises and reaches the melting point of polycarbonate, the polycarbonate is hot-melted and flows and distributes, and the cellulose fibers and polyvinyl alcohol particles are gradually released. The cross-linking effect of hydroxyl groups, stearic acid polyoxyethylene and acrylic resin in polyvinyl alcohol is utilized to improve the connection effect between cellulose fibers and acrylic resin. The water adsorption effect of cellulose fibers and polyvinyl alcohol particles is utilized to ensure that cellulose fibers and polyvinyl alcohol particles can absorb excess water on one side of the drug, thereby ensuring the drug drying effect and ensuring the uniformity of coating.

[0022] The polyvinyl alcohol particles absorb water and increase the bonding effect, further improving the internal stability of the hygroscopic coating and the bonding stability of the hygroscopic coating on the surface of the aluminum foil. Combined with the moisture barrier effect of the polycarbonate around the cellulose fibers, it further prevents moisture from dispersing in various locations inside the hygroscopic coating, making it less likely for the coating on the surface of the aluminum foil to peel off due to water absorption.

[0023] Preferably, the dispersant is composed of hydrogenated castor oil polyoxyethylene ether and sodium dodecylbenzene sulfonate in a mass ratio of 1:1-2.

[0024] By adopting the above technical scheme, hydrogenated castor oil polyoxyethylene ether and sodium dodecylbenzene sulfonate are combined to evenly disperse the polycarbonate coated hygroscopic filler and polycarbonate coated fiber, while ensuring that the acrylic resin coating has good uniformity and fluidity, so as to facilitate uniform and stable adhesion to the surface of the aluminum foil.

[0025] Preferably, the thickener is composed of hydroxyethyl cellulose and rosin resin in a mass ratio of 1:0.2-0.5.

[0026] By adopting the above technical scheme, hydroxyethyl cellulose is dissolved in water for thickening, and rosin resin is dissolved in ethanol for thickening, thereby improving the bonding effect of the coating on the surface of the aluminum foil, and the coating formed by the coating is not easy to peel off the coating at the contact interface between the coating and the aluminum foil due to the moisture problem in the external environment under the high bonding effect of the rosin resin and the water-blocking condition, thereby ensuring that the coating still has a high bonding stability on the surface of the aluminum foil after absorbing moisture.

[0027] Preferably, the curing agent consists of triethylenetetramine and HDI curing agent in a mass ratio of 1:0.5-1.

[0028] By adopting the above technical solution, the coating has higher strength, toughness and better bonding effect, and can stably adhere to the surface of the aluminum foil.

[0029] In a second aspect, the present application provides a method for preparing a hygroscopic coating, using the following technical solution: A method for preparing a hygroscopic coating comprises the following steps: S1. Weigh acrylic resin, 2 / 3 of the total amount of water, ethanol and isopropanol, mix and stir evenly, heat to 70-80°C for reaction for 20-30min, then cool to 40-45°C, add polycarbonate coated hygroscopic filler and fiber material loaded polyvinyl alcohol, mix and stir evenly, finally add dispersant, defoamer and thickener, mix and stir evenly to obtain mixture A; S2, weigh the curing agent and 1 / 3 of the total amount of water, mix and stir evenly to obtain a mixture B; S3. Mixture A and mixture B are mixed and stirred evenly, and used immediately after preparation to obtain a hygroscopic coating.

[0030] By adopting the above technical scheme, the acrylic resin reacts at a relatively high temperature, and then the polycarbonate coated hygroscopic filler and polycarbonate coated fiber are added under the condition of 40-45°C. The melting point of polycarbonate is 60°C, and the hot melting problem is not easy to occur at about 40°C, thereby ensuring the blocking of the hygroscopic filler and the fiber, and avoiding the hygroscopic filler and the fiber from absorbing moisture and alcohol in the coating as much as possible, ensuring that the hygroscopic coating has good fluidity and bonding effect, and ensuring that the hygroscopic filler and the fiber in the hygroscopic coating can absorb moisture on one side of the drug after curing to the surface of the aluminum foil, and the coating can reversely absorb the water vapor in the drug after curing to keep the drug dry; at the same time, the coating formed by the coating can still stably adhere to the surface of the aluminum foil after absorbing moisture.

[0031] In a third aspect, the present application provides a hygroscopic aluminum foil, which adopts the following technical solution: A hygroscopic aluminum foil comprises an aluminum foil and a hygroscopic coating. The hygroscopic coating is prepared by drying the hygroscopic coating at 160-165 DEG C and then subjecting it to a cooling treatment.

[0032] By adopting the above technical solution, curing treatment is carried out at a higher temperature to ensure that the polycarbonate is hot-melted, which can gradually expose the porous structure of the hygroscopic filler and fiber, thereby achieving reverse absorption of water vapor in the medicine and keeping the medicine dry; at the same time, the coating formed by the paint can still stably adhere to the surface of the aluminum foil after absorbing moisture.

[0033] In summary, this application has the following beneficial effects: 1. The polycarbonate coated hygroscopic filler and polycarbonate coated fiber are matched to prevent the hygroscopic filler and fiber from excessively absorbing moisture in the coating during the storage process of the coating and before being coated on the surface of the aluminum foil before the coating is heated and cured, which affects the subsequent absorption of water vapor in the medicine by the hygroscopic filler and fiber, thereby affecting the drying effect of the medicine; and the absorption of moisture in the hygroscopic coating by the hygroscopic filler and fiber is also likely to affect the viscosity of the hygroscopic coating, thereby affecting the uniformity of dispersion of the polycarbonate coated hygroscopic filler and polycarbonate coated fiber on the surface of the aluminum foil, resulting in the uniform drying effect of the medicine being affected; with the thickener, the hygroscopic coating can be stably adhered to the side of the composite aluminum foil close to the medicine.

[0034] 2. Molecular sieves and silica particles have a large specific surface area. Together with the binding network of polycarbonate and silica whiskers, the surface area of ​​the polycarbonate coated hygroscopic filler is further increased. After contacting with acrylic resin, the dispersion stability of the polycarbonate coated hygroscopic filler in the acrylic resin coating can be improved. During the curing process of the coating, the connection between polycarbonate and acrylic resin further improves the bonding stability of the molecular sieve and silica particles on the coating surface, ensuring that the hygroscopic coating is stably attached to the aluminum foil surface.

[0035] 3. The polycarbonate coated hygroscopic filler and polycarbonate coated fiber are matched with each other. The polycarbonate and silica whiskers on the surface of the hygroscopic filler are combined with the polycaprolactone on the surface of the cellulose fiber to improve the contact effect between the fiber and the filler, forming a uniform and interconnected hygroscopic network, promoting the hygroscopic coating to absorb excess moisture on one side of the drug on the aluminum foil surface, thereby ensuring the drying effect of the drug. DETAILED DESCRIPTION

[0036] The present application is further described in detail below with reference to the embodiments.

[0037] The following raw materials are all commercially available.

[0038] Preparation Example of Polycarbonate Coated Hygroscopic Filler Preparation Example 1: Polycarbonate coated hygroscopic filler is prepared by the following method: Weigh 1 kg of molecular sieve and 0.4 kg of silica gel particles and mix and stir evenly to obtain a hygroscopic filler; the molecular sieve has an average particle size of 10 μm and an average porosity of 65%, and the silica gel particles have an average particle size of 5 μm and an average porosity of 50%; 1 kg of porous silica whiskers were placed in 10 kg of silane coupling agent KH-570, and ultrasonically dispersed at 20 kHz for 10 minutes, and then the porous silica whiskers were separated by filtration to obtain silica whiskers, the average length of the silica whiskers was 3 μm, the average diameter was 10 nm, and the average porosity was 15%; 1 kg of hygroscopic filler is placed in 1.5 kg of ammonium bicarbonate solution, which is an ammonium bicarbonate aqueous solution with a mass fraction of 5%, and stirred at a speed of 200 r / min for 30 minutes. The hygroscopic filler is freeze-dried to remove moisture to obtain a loaded filler; 0.7 kg of polycarbonate melt is evenly sprayed on the surface of the loaded filler, and the polycarbonate melt is obtained by heating the polycarbonate to 60° C. and completely melting it. Finally, 0.3 kg of silicon dioxide whisker is added, and the addition rate of the silicon dioxide whisker is 60 g / min. During the addition process, the loaded filler is continuously stirred at a speed of 200 r / min. After the addition is completed, the mixing and stirring are continued for 20 minutes. After the mixing is evenly carried out, it is dried, dispersed, and passed through a 600-mesh sieve to obtain a finished polycarbonate coated hygroscopic filler.

[0039] Preparation Example 2: This preparation example differs from Preparation Example 1 in that: Weigh 1 kg of molecular sieve and 0.2 kg of silica gel particles and mix and stir evenly to obtain a hygroscopic filler; the molecular sieve has an average particle size of 10 μm and an average porosity of 65%, and the silica gel particles have an average particle size of 5 μm and an average porosity of 50%; 1 kg of porous silica whiskers were placed in 10 kg of silane coupling agent KH-570, and ultrasonically dispersed at 20 kHz for 10 minutes, and then the porous silica whiskers were separated by filtration to obtain silica whiskers, the average length of the silica whiskers was 3 μm, the average diameter was 10 nm, and the average porosity was 10%; 1 kg of hygroscopic filler is placed in 1 kg of ammonium bicarbonate solution, which is an ammonium bicarbonate aqueous solution with a mass fraction of 5%, and stirred at a speed of 200 r / min for 30 minutes. The hygroscopic filler is freeze-dried to remove moisture to obtain a loaded filler; 0.5 kg of polycarbonate melt is evenly sprayed on the surface of the loaded filler, and the polycarbonate melt is obtained by heating the polycarbonate to 60° C. to completely melt it, and finally 0.1 kg of silicon dioxide whisker is added, and the addition speed of the silicon dioxide whisker is 60 g / min. During the addition process, the loaded filler is continuously stirred at a speed of 200 r / min. After the addition is completed, the mixing and stirring are continued for 20 minutes. After the mixing is evenly carried out, it is dried, dispersed, and passed through a 600-mesh sieve to obtain a finished polycarbonate coated hygroscopic filler.

[0040] Preparation Example 3: This preparation example differs from Preparation Example 1 in that: Weigh 1 kg of molecular sieve and 0.5 kg of silica gel particles and mix and stir evenly to obtain a hygroscopic filler; the molecular sieve has an average particle size of 10 μm and an average porosity of 65%, and the silica gel particles have an average particle size of 5 μm and an average porosity of 50%; 1 kg of porous silica whiskers were placed in 10 kg of silane coupling agent KH-570, and ultrasonically dispersed at 20 kHz for 10 minutes, and then the porous silica whiskers were separated by filtration to obtain silica whiskers, the average length of the silica whiskers was 3 μm, the average diameter was 10 nm, and the average porosity was 15%; 1 kg of hygroscopic filler is placed in 2 kg of ammonium bicarbonate solution, which is an ammonium bicarbonate aqueous solution with a mass fraction of 5%, and stirred at a speed of 200 r / min for 30 minutes. The hygroscopic filler is freeze-dried to remove moisture to obtain a loaded filler; 1 kg of polycarbonate melt is evenly sprayed on the surface of the loaded filler, and the polycarbonate melt is obtained by heating the polycarbonate to 60° C. to completely melt it, and finally 0.5 kg of silicon dioxide whisker is added, and the addition speed of the silicon dioxide whisker is 60 g / min. During the addition process, the loaded filler is continuously stirred at a speed of 200 r / min. After the addition is completed, the mixing and stirring are continued for 20 minutes. After the mixing is evenly carried out, it is dried, dispersed, and passed through a 600-mesh sieve to obtain a finished polycarbonate coated hygroscopic filler.

[0041] Preparation example of polycarbonate coated fiber Preparation Example 4: Polycarbonate coated fibers were prepared by the following method: The polycarbonate is heated to 60°C and completely melted to obtain a polycarbonate melt; 0.2 kg of polycarbonate melt was evenly sprayed on the surface of 1 kg of cellulose fibers, the average length of the cellulose fibers was 20 μm, and the average diameter was 20 nm. Then 0.2 kg of polyethylene particles were added, the average particle size of the polyethylene particles was 3 μm, and the addition rate of the polyethylene particles was 60 g / min. During the addition process, the cellulose fibers were continuously stirred at a speed of 200 r / min. After the addition was completed, 0.6 kg of polycarbonate melt was continued to be evenly sprayed, and the polycarbonate coated fibers were obtained after drying and dispersion until the cellulose fibers did not stick to each other and agglomerate.

[0042] Preparation Example 5: This preparation example differs from Preparation Example 4 in that: 0.1 kg of polycarbonate melt was evenly sprayed on the surface of 1 kg of cellulose fibers, the average length of the cellulose fibers was 20 μm, and the average diameter was 20 nm. Then 0.1 kg of polyethylene particles were added, the average particle size of the polyethylene particles was 3 μm, and the addition rate of the polyethylene particles was 60 g / min. During the addition process, the cellulose fibers were continuously stirred at a speed of 200 r / min. After the addition was completed, 0.4 kg of polycarbonate melt was continued to be evenly sprayed, and the polycarbonate coated fibers were obtained after drying and dispersion until the cellulose fibers did not stick to each other and agglomerate.

[0043] Preparation Example 6: This preparation example differs from Preparation Example 4 in that: 0.3 kg of polycarbonate melt was evenly sprayed on the surface of 1 kg of cellulose fibers, the average length of the cellulose fibers was 20 μm, and the average diameter was 20 nm. Then 0.3 kg of polyethylene particles were added, the average particle size of the polyethylene particles was 3 μm, and the addition rate of the polyethylene particles was 60 g / min. During the addition process, the cellulose fibers were continuously stirred at a speed of 200 r / min. After the addition was completed, 0.7 kg of polycarbonate melt was continued to be evenly sprayed, and the polycarbonate coated fibers were obtained after drying and dispersion until the cellulose fibers did not stick to each other and agglomerate. Example

[0044] Among the following raw materials, acrylic resin was purchased from Changzhou Gene New Materials Co., Ltd., water-soluble acrylic resin JE-6132; other raw materials are all commercially available.

[0045] Example 1: A hygroscopic coating: 25kg of acrylic resin, 60kg of water, 6kg of ethanol, 5kg of isopropanol, 3kg of polycarbonate coated hygroscopic filler, 2kg of polycarbonate coated fiber, 1.5kg of dispersant, 1kg of defoamer, 1.5kg of thickener, and 3kg of curing agent; the mass fraction of ethanol is 99%, the polycarbonate coated hygroscopic filler is the polycarbonate coated hygroscopic filler prepared in Preparation Example 1, and the polycarbonate coated fiber is the polycarbonate coated fiber prepared in Preparation Example 4; the dispersant is composed of hydrogenated castor oil polyoxyethylene ether and sodium dodecylbenzene sulfonate in a mass ratio of 1:1; the thickener is composed of hydroxyethyl cellulose and rosin resin in a mass ratio of 1:0.5; the curing agent is composed of triethylenetetramine and HDI curing agent in a mass ratio of 1:1; the defoamer is an organic silicon defoamer; The preparation method is as follows: S1, weighing acrylic resin, 40kg water, ethanol and isopropanol, mixing and stirring evenly, heating to 75°C for reaction for 25min, then cooling to 40°C, adding polycarbonate coated hygroscopic filler and fiber material loaded polyvinyl alcohol, mixing and stirring evenly, finally adding dispersant, defoamer and thickener, mixing and stirring evenly, to obtain mixture A; S2, weigh the curing agent and 20 kg of water, mix and stir evenly to obtain a mixture B; S3. Mixture A and mixture B are mixed and stirred evenly, and used immediately after preparation to obtain a hygroscopic coating.

[0046] Embodiment 2: This embodiment differs from Embodiment 1 in that: 20kg of acrylic resin, 36kg of water, 1kg of ethanol, 1kg of isopropanol, 1kg of polycarbonate coated hygroscopic filler, 1kg of polycarbonate coated fiber, 1kg of dispersant, 1kg of defoamer, 1kg of thickener, and 2kg of curing agent; the mass fraction of ethanol is 99%, the polycarbonate coated hygroscopic filler is the polycarbonate coated hygroscopic filler prepared in Preparation Example 2, and the polycarbonate coated fiber is the polycarbonate coated fiber prepared in Preparation Example 5; the dispersant is composed of hydrogenated castor oil polyoxyethylene ether and sodium dodecylbenzene sulfonate in a mass ratio of 1:1; the thickener is composed of hydroxyethyl cellulose and rosin resin in a mass ratio of 1:0.2; the curing agent is composed of triethylenetetramine and HDI curing agent in a mass ratio of 1:0.5; the defoamer is a silicone defoamer; The preparation method is as follows: S1, weighing acrylic resin, 24kg water, ethanol and isopropanol, mixing and stirring evenly, heating to 70°C for reaction for 30min, then cooling to 40°C, adding polycarbonate coated hygroscopic filler and fiber material loaded polyvinyl alcohol, mixing and stirring evenly, finally adding dispersant, defoamer and thickener, mixing and stirring evenly, to obtain mixture A; S2, weigh the curing agent and 12 kg of water, mix and stir evenly to obtain a mixture B; S3. Mixture A and mixture B are mixed and stirred evenly, and used immediately after preparation to obtain a hygroscopic coating.

[0047] Embodiment 3: This embodiment differs from Embodiment 1 in that: 30kg of acrylic resin, 70kg of water, 10kg of ethanol, 10kg of isopropanol, 5kg of polycarbonate coated hygroscopic filler, 3kg of polycarbonate coated fiber, 2kg of dispersant, 2kg of defoamer, 2kg of thickener, and 4kg of curing agent; the mass fraction of ethanol is 99%, the polycarbonate coated hygroscopic filler is the polycarbonate coated hygroscopic filler prepared in Preparation Example 3, and the polycarbonate coated fiber is the polycarbonate coated fiber prepared in Preparation Example 6; the dispersant is composed of hydrogenated castor oil polyoxyethylene ether and sodium dodecylbenzene sulfonate in a mass ratio of 1:2; the thickener is composed of hydroxyethyl cellulose and rosin resin in a mass ratio of 1:0.5; the curing agent is composed of triethylenetetramine and HDI curing agent in a mass ratio of 1:1; the defoamer is a silicone defoamer; The preparation method is as follows: S1, weighing acrylic resin, 48kg water, ethanol and isopropanol, mixing and stirring evenly, heating to 80°C for reaction for 20min, then cooling to 45°C, adding polycarbonate coated hygroscopic filler and fiber material loaded polyvinyl alcohol, mixing and stirring evenly, finally adding dispersant, defoamer and thickener, mixing and stirring evenly, to obtain mixture A; S2, weigh the curing agent and 24 kg of water, mix and stir evenly to obtain a mixture B; S3. Mixture A and mixture B are mixed and stirred evenly, and used immediately after preparation to obtain a hygroscopic coating.

[0048] Embodiment 4: This embodiment differs from Embodiment 1 in that: During the preparation of the polycarbonate coated hygroscopic filler, no silicon dioxide whiskers were added, and the hygroscopic filler was sodium carboxymethyl cellulose particles.

[0049] Embodiment 5: This embodiment differs from Embodiment 1 in that: During the preparation of the polycarbonate coated hygroscopic filler, no ammonium bicarbonate solution was added.

[0050] Embodiment 6: This embodiment differs from Embodiment 1 in that: No polyvinyl alcohol particles were added during the preparation of the polycarbonate coated fibers.

[0051] Comparative Example Comparative Example 1: The difference between this comparative example and Example 1 is that: The polycarbonate coated hygroscopic filler is replaced by an equal mass of silica gel particles in the raw materials, and the polycarbonate coated fiber is replaced by an equal mass of cellulose fiber.

[0052] Application Examples Application example 1: A hygroscopic aluminum foil: Includes aluminum foil and moisture-absorbing coating; The preparation method is as follows: Spray the hygroscopic coating evenly on the surface of the aluminum foil, with a dry coating weight of 1g / m 2 , use a 220-mesh coating roller, after coating, dry at 160°C for 20s, and cool to room temperature at a rate of 1°C / min. The hygroscopic coating is cured to form a hygroscopic coating. The hygroscopic coating is the hygroscopic coating prepared in Example 1, and a medicinal aluminum foil is obtained.

[0053] Application Example 2 The difference between this application example and application example 1 is: The hygroscopic coating is the hygroscopic coating prepared in Example 2; The preparation method is as follows: Spray the hygroscopic coating evenly on the surface of the aluminum foil, with a dry coating weight of 1g / m 2 , use a 220-mesh coating roller, and after coating, dry at 165°C for 15s. The hygroscopic coating is cured to form a hygroscopic coating to obtain a medicinal aluminum foil.

[0054] Application Example 3-6: The difference between this application example and application example 1 is: The hygroscopic coatings correspond to the hygroscopic coatings prepared in Examples 3-6 respectively.

[0055] Comparative Application Examples Comparative Application Example 1: The difference between this comparative application example and application example 1 is: The hygroscopic coating is the hygroscopic coating prepared in Comparative Example 1.

[0056] Performance testing 1. Adhesion effect detection The hygroscopic aluminum foil was prepared by the methods of Application Examples 1-4, 6 and Comparative Application Example 1, and the peel strength of the coating on the surface of the aluminum foil was tested with reference to GB / T 25264, and the data was recorded; the greater the peel strength, the higher the bonding strength.

[0057] 2. Moisture absorption effect test The hygroscopic aluminum foil was prepared by the methods of Application Examples 1-3, 5-6 and Comparative Application Example 1 respectively. The aluminum foil was placed in a closed condition with a relative humidity of 75% and an ambient temperature of 28°C for 8 hours. The relative humidity of the environment was then tested and recorded as the relative humidity after moisture absorption. The relative humidity difference was recorded as the initial relative humidity - the relative humidity after moisture absorption. The larger the difference, the better the moisture absorption effect, which can ensure the drying effect of the medicine.

[0058] 3. Adhesion effect test after moisture absorption The hygroscopic aluminum foil was prepared by the methods of Application Examples 1-4, 6 and Comparative Application Example 1, and the hygroscopic aluminum foil was placed under relative humidity of 75°C and temperature of 25°C for 2 hours. The peel strength of the coating on the surface of the aluminum foil was tested with reference to GB / T 25264, and the data was recorded. The greater the peel strength, the higher the bonding strength.

[0059] Table 1 Performance test table (“ / ” in the table means that the corresponding application example or comparative application example did not test the item, so there is no data) It can be seen from Application Examples 1-3 and Table 1 that after the coating prepared in the present application forms a coating on the surface of the aluminum foil, it has a high bonding strength, a low peel strength, and a certain hygroscopic effect, which can absorb excess moisture on the side close to the drug to ensure the drying effect of the drug.

[0060] Combining Application Example 1 and Application Examples 4-6 and Table 1, it can be seen that in the preparation process of the polycarbonate coated hygroscopic filler in Application Example 4, no silica whiskers were added, and the hygroscopic filler was sodium carboxymethyl cellulose particles. Compared with Application Example 1, the peel strength of the coating on the hygroscopic aluminum foil prepared in Application Example 4 was lower than that in Application Example 1, and the peel strength after moisture absorption was lower than that in Application Example 1; this indicates that the presence of silica whiskers can restrain the hygroscopic filler, making it less likely to cause expansion problems after moisture absorption, and improve the bonding density between the hygroscopic filler and the acrylic resin. At the same time, the hygroscopic filler is limited to molecular sieves and hydrophobically treated silica gel particles, which are less likely to cause moisture absorption and expansion problems, thereby ensuring the bonding stability of the coating on the aluminum foil surface.

[0061] During the preparation of the polycarbonate coated hygroscopic filler in Application Example 5, ammonium bicarbonate solution was not added. Compared with Application Example 1, the hygroscopic aluminum foil prepared in Application Example 5 had a worse hygroscopic effect than that in Application Example 1. This indicates that the ammonium bicarbonate solution can thermally decompose and produce gas during the temperature increase and curing process, ensuring that the pores in the hygroscopic filler are connected to the external environment, thereby ensuring the hygroscopic effect of the hygroscopic coating on the surface of the aluminum foil.

[0062] In the preparation process of the polycarbonate coated fiber in Application Example 6, no polyvinyl alcohol particles were added. Compared with Application Example 1, the peeling strength of the coating on the hygroscopic aluminum foil prepared in Application Example 6 was lower than that in Application Example 1, and the peeling strength after moisture absorption was lower than that in Application Example 1, and the moisture absorption effect was worse than that in Application Example 1. This shows that the addition of polyvinyl alcohol particles can absorb excess moisture on one side of the drug to ensure the drying effect of the drug, and the polyvinyl alcohol particles have a certain bonding effect, which can ensure the adhesion stability of the coating on the surface of the aluminum foil, thereby extending the service life of the hygroscopic aluminum foil and preventing the problem of layer peeling after moisture absorption.

[0063] Combining Application Example 1 and Comparative Application Example 1 and Table 1, it can be seen that the polycarbonate coated hygroscopic filler in the raw material of Comparative Application Example 1 is replaced with the same mass of silica gel particles, and the polycarbonate coated fiber is replaced with the same mass of cellulose fiber. Compared with Application Example 1, the peeling strength of the coating on the hygroscopic aluminum foil prepared in Comparative Application Example 1 is lower than that in Application Example 1, and the peeling strength after moisture absorption is lower than that in Application Example 1, and the moisture absorption effect is worse than that in Application Example 1; this indicates that the coating treatment of polycarbonate ensures that the coating is not easy to excessively absorb moisture in the coating before storage and curing, which affects the subsequent absorption effect of the hygroscopic filler on the moisture of the external environment. , and ensure the uniformity of coating on the surface of aluminum foil, the uniform distribution of polycarbonate coated hygroscopic filler and polycarbonate coated fiber, the gradual hot melting of polycarbonate and the connection effect of hygroscopic filler and fiber to acrylic resin during the temperature rise and curing process, further improve the adhesion effect of coating on the surface of aluminum foil, and at the same time utilize the barrier effect of polycarbonate to block the moisture absorbed by hygroscopic filler and fiber, and try to avoid the influence of moisture in acrylic resin on its internal structure stability, and also ensure the adhesion stability of coating on the surface of aluminum foil, and it is not easy to have the problem of coating peeling off from the surface of aluminum foil after moisture absorption.

[0064] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A hygroscopic coating, characterized in that: The invention comprises the following raw materials in parts by weight: 20-30 parts of acrylic resin, 36-72 parts of water, 1-10 parts of ethanol, 1-10 parts of isopropanol, 1-5 parts of polycarbonate coated hygroscopic filler, 1-3 parts of polycarbonate coated fiber, 1-2 parts of dispersant, 1-2 parts of defoamer, 1-2 parts of thickener and 2-4 parts of curing agent.

2. A hygroscopic coating according to claim 1, characterized in that: The polycarbonate coated hygroscopic filler is prepared from a hygroscopic filler, an ammonium bicarbonate solution, a polycarbonate melt and a silicon dioxide whisker in a mass ratio of 1:1-2:0.5-1:0.1-0.

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3. A hygroscopic coating according to claim 2, characterized in that: The hygroscopic filler is made of molecular sieve and silica gel particles in a mass ratio of 1:0.2-0.

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4. A hygroscopic coating according to claim 2, characterized in that: The silicon dioxide whisker is prepared from porous silicon dioxide whisker by treating it with silane coupling agent KH-570, and the average porosity of the silicon dioxide whisker is 10-15%.

5. A hygroscopic coating according to claim 1, characterized in that: The polycarbonate coated fiber is made of cellulose fiber, polyvinyl alcohol particles and polycarbonate melt in a mass ratio of 1:0.1-0.3:0.5-1.

6. A hygroscopic coating according to claim 1, characterized in that: The dispersant is composed of hydrogenated castor oil polyoxyethylene ether and sodium dodecylbenzene sulfonate in a mass ratio of 1:1-2.

7. A hygroscopic coating according to claim 1, characterized in that: The thickener is composed of hydroxyethyl cellulose and rosin resin in a mass ratio of 1:0.2-0.

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8. A hygroscopic coating according to claim 1, characterized in that: The curing agent is composed of triethylenetetramine and HDI curing agent in a mass ratio of 1:0.5-1.

9. A method for preparing a hygroscopic coating according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Weigh acrylic resin, 2 / 3 of the total amount of water, ethanol and isopropanol, mix and stir evenly, heat to 70-80°C for reaction for 20-30min, then cool to 40-45°C, add polycarbonate coated hygroscopic filler and fiber material loaded polyvinyl alcohol, mix and stir evenly, finally add dispersant, defoamer and thickener, mix and stir evenly to obtain mixture A; S2, weigh the curing agent and 1 / 3 of the total amount of water, mix and stir evenly to obtain a mixture B; S3. Mixture A and mixture B are mixed and stirred evenly, and used immediately after preparation to obtain a hygroscopic coating.

10. A hygroscopic aluminum foil, characterized in that: The invention comprises aluminum foil and a hygroscopic coating, wherein the hygroscopic coating is prepared by drying the hygroscopic coating at 160-165° C. and then subjecting it to a cooling treatment; the hygroscopic coating is selected from the hygroscopic coating prepared according to claims 1-8 or the hygroscopic coating prepared according to the preparation method of the hygroscopic coating according to claim 9.

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