Environment-friendly degradable water-soluble PVA packaging adhesive tape and preparation method thereof

Abstract

The invention belongs to the technical field of packaging materials. The invention relates to a PVA packaging adhesive tape, in particular to an environment-friendly degradable water-soluble PVA packaging adhesive tape and a preparation method thereof. The product comprises a base material layer and a bonding layer, the base material layer is prepared from the following raw materials in parts by weight: 60 to 70 parts of polyvinyl alcohol, 10 to 12 parts of polyethylene glycol, 6 to 8 parts of sodium alginate, 5 to 10 parts of glycerol and 10 to 12 parts of spherical clay particles; wherein the particle size distribution range of the spherical clay particles is 10-30 nm; in addition, the sphericity degree of the spherical clay particles is 0.9 to 0.95; the bonding layer is prepared from the following raw materials in parts by weight: 45 to 55 parts of sodium carboxymethyl cellulose and 25 to 35 parts of hydroxyethyl cellulose. The Mohs hardness of the spherical clay particles is 1-2; the surfaces of the spherical clay particles comprise buffer layers, and the buffer layers are made of polyacrylate.

Description

Technical Field

[0001] This invention belongs to the field of packaging materials technology. More specifically, it relates to an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape and its preparation method. Background Technology

[0002] For PVA encapsulation tapes, environmentally friendly components such as polyethylene glycol (PEG), sodium alginate, and glycerin are added to the substrate layer. PEG gives the substrate good flexibility and water solubility, while sodium alginate enhances strength and biodegradability. Glycerin is a commonly used plasticizer that can weaken hydrogen bonds between molecular chains and improve processability, thereby improving the flexibility and ductility of the product.

[0003] However, during product processing and use, the inventors discovered that the addition of polyethylene glycol may reduce the crystallinity of PVA in the substrate, thereby reducing the gas barrier performance; the introduction of sodium alginate will significantly increase the water absorption rate of PVA; and the introduction of glycerin will also lead to a decrease in the crystallinity of PVA. The simple introduction of these substances ultimately leads to the performance degradation of water-soluble PVA encapsulation tape during storage and use, resulting in a reduction in the product's lifespan.

[0004] Therefore, how to maintain the performance stability of water-soluble PVA encapsulation tape during storage and use is one of the technical challenges that those skilled in the art will continue to face. Summary of the Invention

[0005] The technical problem this invention aims to solve is that, in order to achieve good environmental performance in environmentally friendly, biodegradable, water-soluble PVA encapsulation tapes, components such as polyethylene glycol, sodium alginate, and glycerin are often introduced. However, the introduction of these components leads to a decrease in the crystallinity of PVA, resulting in a decline in product performance. Based on this problem, this invention provides an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape and its preparation method.

[0006] The purpose of this invention is to provide an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape.

[0007] Another objective of this invention is to provide a method for preparing an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape.

[0008] The above-mentioned objective of this invention is achieved through the following technical solution: An environmentally friendly, biodegradable, water-soluble PVA encapsulation tape, comprising a substrate layer and an adhesive layer; The substrate layer comprises the following raw materials in parts by weight: 60-70 parts polyvinyl alcohol, 10-12 parts polyethylene glycol, 6-8 parts sodium alginate, 5-10 parts glycerol, and 10-12 parts spherical clay particles. The particle size distribution range of the spherical clay particles is 10-30 nm; Furthermore, the sphericity of the spherical clay particles is 0.9-0.95; The adhesive layer comprises the following raw materials in parts by weight: 45-55 parts sodium carboxymethyl cellulose and 25-35 parts hydroxyethyl cellulose.

[0009] The beneficial effects of the above technical solution are as follows: The above technical solution improves the product performance degradation caused by insufficient substrate stability by introducing spherical clay particles into the substrate of the tape. Specifically, the clay particles in the substrate can act as a physical barrier to block the penetration and diffusion of substances such as oxygen and water vapor, thereby enhancing the product's durability in humid and hot environments. However, the inventors discovered that the introduction of components such as polyethylene glycol, sodium alginate and glycerin would lead to a decrease in the crystallinity of PVA. This decrease would weaken the interaction forces between PVA molecular chains, which would affect the uniform dispersion of clay particles in the substrate. If the particles could not be uniformly dispersed, it would lead to uneven performance of the substrate, resulting in preferential failure due to local weakness, and ultimately a rapid decline in the overall service life of the product. Based on this, the inventors addressed this problem in the above technical solution by using spherical clay particles and nanoscale spherical particles with a relatively narrow particle size distribution range. Specifically, a narrow particle size distribution range means that the particle size is relatively concentrated, with fewer large and small particles, thus avoiding the problems caused by the uneven distribution of these particles. Furthermore, particles with higher sphericity have better flowability between particles, and due to their regular shape and similar size specifications between particles, they can better adapt to the shear force of the mixing equipment during the preparation process, thereby helping to form a uniform distribution in the matrix.

[0010] Furthermore, the spherical clay particles have a Mohs hardness of 1-2.

[0011] The beneficial effects of the above technical solution are as follows: By adjusting the Mohs hardness of spherical clay particles, specifically, one could consider further coating their surface with an organic coating layer to change their Mohs hardness; however, this is not the only option. Particles with a Mohs hardness in the lower range mentioned above tend to maintain their integrity during processing. Low-hardness clay particles are less likely to break due to shear forces during mixing or processing, which helps maintain the original particle size distribution and avoids agglomeration or sedimentation caused by particle breakage. Furthermore, softer particles are more easily wetted and encapsulated by the PVA substrate, reducing interfacial energy and thus reducing the tendency to agglomerate.

[0012] Furthermore, the surface of the spherical clay particles includes a buffer layer composed of polyacrylate.

[0013] The beneficial effects of the above technical solution are as follows: The above technical solution further improves the dispersibility of the product by forming a buffer layer composed of polyacrylate on the surface of clay particles.

[0014] Furthermore, the thickness of the substrate layer is 60-80 μm; the thickness of the adhesive layer is 0.8-1.0 times the thickness of the substrate layer.

[0015] Furthermore, the polyvinyl alcohol has a degree of alcoholysis of 87-89%, an average degree of polymerization of 2400-2500, and a weight-average molecular weight of 118000-124000.

[0016] Furthermore, the polyethylene glycol is selected from any one of PEG 400, PEG 600, and PEG 1000.

[0017] A method for preparing an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape, comprising the following specific steps: Prepare each component according to the raw material composition; Preparation of substrate layer: Polyvinyl alcohol and water are mixed and dissolved to obtain a polyvinyl alcohol solution with a mass fraction of 10-20%. Polyethylene glycol, sodium alginate and glycerin were added to a polyvinyl alcohol solution and stirred until homogeneous. Then, spherical clay particles were added and ultrasonically dispersed until homogeneous to obtain a substrate coating solution. The substrate coating liquid is applied and then dried to obtain the substrate layer; Preparation of the adhesive layer: Sodium carboxymethyl cellulose and hydroxyethyl cellulose are dissolved in water, wherein the mass of water is 8-10 times the total mass of sodium carboxymethyl cellulose and hydroxyethyl cellulose; to obtain a binder layer solution. The adhesive layer solution is applied to the surface of the substrate layer and then dried to obtain a substrate loaded with the adhesive layer. complex: The substrate with the adhesive layer is rolled and laminated, and then cut to obtain an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape.

[0018] Furthermore, the preparation steps of the spherical clay particles include: Montmorillonite was acid-washed with hydrochloric acid and then washed with deionized water until neutral to obtain impurity-free montmorillonite. Subsequently, the impurity-removed montmorillonite was dispersed in an ethanol solution, and 25-30% by weight of hexadecyltrimethylammonium bromide was added. After microwave ultrasonic reaction, the mixture was filtered, washed, and dried to obtain intercalated modified montmorillonite. Intercalated modified montmorillonite was ultrasonically dispersed in water and extruded through a 0.2-0.3 μm filter membrane to obtain clay sol. Ammonia was then added to the sol to adjust the pH to 9.2-9.6. After standing for 3-6 hours to gel, the sol was spray-granulated to obtain spherical particles. Spherical particles are heated to 400-450℃, kept at that temperature and calcined, then sieved and graded to obtain spherical clay particles.

[0019] Furthermore, the preparation steps of the spherical clay particles also include: The spherical particles are heated to 400-450℃ and calcined for a period of time to obtain the calcined material. After mixing the calcined material and water at a mass ratio of 1:80, the mixture is ultrasonically dispersed. Then, 20-30% of the mass of the calcined material is added to the mixture. The mixture is heated and stirred at 70-80℃ for 80-120 minutes to obtain a pretreated calcined material dispersion. By weight, take 100-110 parts of the pretreated calcined material dispersion, 6-8 parts of the bifunctional acrylate resin, 1-1.2 parts of the photoinitiator 2-hydroxy-2-methyl-1-phenylpropanone, and 6-8 parts of the cosolvent isoamyl acetate. First, stir and emulsify at room temperature, and then ultrasonically emulsify at an ultrasonic frequency of 60-70 kHz for 10-15 min to obtain a stable emulsion. The stable emulsion was continuously injected into the reactor at a rate of 10 mL / min and irradiated with a 365 nm UV-LED lamp for 15-20 min for UV curing. After centrifugation, the emulsion was washed, dried, and sieved to obtain spherical clay particles. Detailed Implementation

[0020] The present invention will be further illustrated below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in this technical field.

[0021] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0022] Example 1 Preparation of spherical clay particles: Montmorillonite was acid-washed with 1 mol / L hydrochloric acid at 80°C for 20 min, and then washed with deionized water until neutral to obtain impurity-free montmorillonite; the amount of hydrochloric acid used was 10 times the mass of montmorillonite. Subsequently, the impurity-removed montmorillonite was dispersed in a 50% ethanol solution, and 25% of the mass of the impurity-removed montmorillonite was added with cetyltrimethylammonium bromide. The mixture was subjected to microwave ultrasonic reaction at a power of 300W and an ultrasonic frequency of 80kHz for 30 minutes. After filtration, washing and drying, the intercalated modified montmorillonite was obtained. The amount of ethanol solution used was 8 times the mass of the impurity-removing montmorillonite. Intercalated modified montmorillonite was ultrasonically dispersed in water at a frequency of 80 kHz for 20 min, with the amount of water being 20 times the mass of the intercalated modified montmorillonite. The mixture was then extruded through a 0.2 μm filter membrane to obtain a clay sol. Ammonia was added to the sol to adjust the pH to 9.2. After standing for 3 h to gel, the sol was spray-granulated. During spray granulation, the inlet temperature was controlled at 180℃, the outlet temperature at 90℃, and the atomization pressure at 0.2 MPa. The feed rate was controlled at 15 mL / min to dry the droplets and obtain spherical particles. Spherical particles were heated to 400°C at a rate of 3°C / min, held at that temperature for 60 min, cooled, and discharged to obtain calcined material. After mixing the calcined material and water at a mass ratio of 1:80, the mixture was ultrasonically dispersed for 20 minutes at a frequency of 80 kHz. Then, 20% of the mass of the calcined material was added to the mixture, and the mixture was heated and stirred at 70°C for 80 minutes to obtain a pretreated calcined material dispersion. By weight, take 100 parts of pretreated calcined material dispersion, 6 parts of bifunctional acrylate resin, 1 part of photoinitiator 2-hydroxy-2-methyl-1-phenylpropanone, and 6 parts of cosolvent isoamyl acetate. First, at room temperature, use a stirrer to emulsify at 600 r / min for 30 min, and then use an ultrasonic emulsifier at 60 kHz for 10 min to obtain a stable emulsion. The stable emulsion was continuously injected into the reactor at a rate of 10 mL / min and irradiated with a 365 nm UV-LED lamp for 15 min for UV curing. After centrifugation, washing, drying and sieving were performed to obtain spherical clay particles. Among them, the spherical clay particles are selected with a particle size distribution range of 10-30nm; sphericity of 0.9; and surface coating to achieve a Mohs hardness of 2. Substrate layer raw material preparation: By weight, take 60 parts polyvinyl alcohol, 10 parts polyethylene glycol, 6 parts sodium alginate, 5 parts glycerin, and 10 parts spherical clay particles. The polyvinyl alcohol has a degree of alcoholysis of 87%, an average degree of polymerization of 2400, and a weight-average molecular weight of 118,000. The polyethylene glycol is selected from PEG 400; Preparation of adhesive layer materials: By weight, take 45 parts sodium carboxymethyl cellulose and 25 parts hydroxyethyl cellulose; Preparation of substrate layer: Polyvinyl alcohol and water are mixed and dissolved to obtain a polyvinyl alcohol solution with a mass fraction of 10%. Polyethylene glycol, sodium alginate and glycerin were added to a polyvinyl alcohol solution and stirred at 600 r / min for 2 h. Spherical clay particles were then added and ultrasonically dispersed at 75 ℃ and 200 kHz for 2 h to obtain a substrate coating solution. After the substrate coating liquid is applied, it is transferred to an oven and dried at 60°C for 2 hours to obtain a substrate layer with a thickness of 60μm. Preparation of the adhesive layer: Sodium carboxymethyl cellulose and hydroxyethyl cellulose are dissolved in water, wherein the mass of water is 8 times the total mass of sodium carboxymethyl cellulose and hydroxyethyl cellulose; to obtain a binder layer solution. An adhesive layer solution is applied to the surface of a substrate layer and then dried at 60°C to a constant weight to obtain a substrate loaded with an adhesive layer, wherein the thickness of the adhesive layer is 0.8 times the thickness of the substrate layer. complex: The substrate with the adhesive layer is rolled and laminated under a pressure of 3.2 MPa and a temperature of 50°C, and then cut to obtain an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape.

[0023] Example 2 Preparation of spherical clay particles: Montmorillonite was acid-washed with 1 mol / L hydrochloric acid at 80°C for 20 min, and then washed with deionized water until neutral to obtain impurity-free montmorillonite; the amount of hydrochloric acid used was 10 times the mass of montmorillonite. Subsequently, the impurity-removed montmorillonite was dispersed in a 50% ethanol solution, and 28% of the mass of the impurity-removed montmorillonite was added with cetyltrimethylammonium bromide. The mixture was subjected to microwave ultrasonic reaction at a power of 300W and an ultrasonic frequency of 80kHz for 35 minutes. After filtration, washing and drying, the intercalated modified montmorillonite was obtained. The amount of ethanol solution used was 8 times the mass of the impurity-removing montmorillonite. Intercalated modified montmorillonite was ultrasonically dispersed in water at a frequency of 80 kHz for 20 min, with the amount of water being 20 times the mass of the intercalated modified montmorillonite. The mixture was then extruded through a 0.26 μm filter membrane to obtain a clay sol. Ammonia was added to the sol to adjust the pH to 9.4. After gelation by standing for 5 h, the sol was spray-granulated. During spray granulation, the inlet temperature was controlled at 180℃, the outlet temperature at 90℃, and the atomization pressure at 0.2 MPa. The feed rate was controlled at 15 mL / min to dry the droplets and obtain spherical particles. Spherical particles were heated to 420°C at a rate of 4°C / min, held at that temperature for 70 min, cooled, and discharged to obtain calcined material. After mixing the calcined material and water at a mass ratio of 1:80, the mixture was ultrasonically dispersed at a frequency of 80kHz for 20 minutes. Then, 25% of the mass of the calcined material was added to the mixture, and the mixture was heated and stirred at 76℃ for 100 minutes to obtain the pretreated calcined material dispersion. By weight, take 105 parts of pretreated calcined material dispersion, 7 parts of bifunctional acrylate resin, 1.1 parts of photoinitiator 2-hydroxy-2-methyl-1-phenylpropanone, and 7 parts of cosolvent isoamyl acetate. First, at room temperature, use a stirrer to emulsify at 600 r / min for 30 min, and then use an ultrasonic emulsifier at 65 kHz for 12 min to obtain a stable emulsion. The stable emulsion was continuously injected into the reactor at a rate of 10 mL / min and irradiated with a 365 nm UV-LED lamp for 18 min for UV curing. After centrifugation, washing, drying and sieving were performed to obtain spherical clay particles. Among them, the spherical clay particles are selected with a particle size distribution range of 10-30nm; sphericity is 0.92; and surface coating makes its Mohs hardness 1. Substrate layer raw material preparation: By weight, take 65 parts polyvinyl alcohol, 11 parts polyethylene glycol, 7 parts sodium alginate, 8 parts glycerin, and 11 parts spherical clay particles. The polyvinyl alcohol has a degree of alcoholysis of 88%, an average degree of polymerization of 2450, and a weight-average molecular weight of 120,000. The polyethylene glycol is selected from PEG 600; Preparation of adhesive layer materials: Take 50 parts by weight of sodium carboxymethyl cellulose and 30 parts by weight of hydroxyethyl cellulose; Preparation of substrate layer: Polyvinyl alcohol and water are mixed and dissolved to obtain a polyvinyl alcohol solution with a mass fraction of 15%. Polyethylene glycol, sodium alginate and glycerin were added to a polyvinyl alcohol solution and stirred at 600 r / min for 2 h. Spherical clay particles were then added and ultrasonically dispersed at 75 ℃ and 200 kHz for 2 h to obtain a substrate coating solution. After the substrate coating liquid is applied, it is transferred to an oven and dried at 65°C for 3 hours to obtain a substrate layer with a thickness of 70μm. Preparation of the adhesive layer: Sodium carboxymethyl cellulose and hydroxyethyl cellulose are dissolved in water, wherein the mass of water is 9 times the total mass of sodium carboxymethyl cellulose and hydroxyethyl cellulose; to obtain a binder layer solution. An adhesive layer solution is applied to the surface of a substrate layer and then dried at 65°C to a constant weight to obtain a substrate loaded with an adhesive layer, wherein the thickness of the adhesive layer is 0.9 times the thickness of the substrate layer. complex: The substrate with the adhesive layer is rolled and laminated under a pressure of 3.3 MPa and a temperature of 52°C, and then cut to obtain an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape.

[0024] Example 3 Preparation of spherical clay particles: Montmorillonite was acid-washed with 1 mol / L hydrochloric acid at 80°C for 20 min, and then washed with deionized water until neutral to obtain impurity-free montmorillonite; the amount of hydrochloric acid used was 10 times the mass of montmorillonite. Subsequently, the impurity-removed montmorillonite was dispersed in a 50% ethanol solution, and 30% of the mass of the impurity-removed montmorillonite was added with cetyltrimethylammonium bromide. The mixture was subjected to microwave ultrasonic reaction at a power of 300W and an ultrasonic frequency of 80kHz for 40 minutes. After filtration, washing and drying, the intercalated modified montmorillonite was obtained. The amount of ethanol solution used was 8 times the mass of the impurity-removing montmorillonite. Intercalated modified montmorillonite was ultrasonically dispersed in water at a frequency of 80 kHz for 20 min, with the amount of water being 20 times the mass of the intercalated modified montmorillonite. The mixture was then extruded through a 0.3 μm filter membrane to obtain a clay sol. Ammonia was added to the sol to adjust the pH to 9.6, and after standing for 6 h to gel, it was spray-granulated. During the spray granulation process, the inlet temperature was controlled at 180℃, the outlet temperature at 90℃, and the atomization pressure at 0.2 MPa. The feed rate was controlled at 15 mL / min to dry the droplets and obtain spherical particles. Spherical particles were heated to 450°C at a rate of 5°C / min, held at that temperature for 80 minutes, cooled, and discharged to obtain calcined material. After mixing the calcined material and water at a mass ratio of 1:80, the mixture was ultrasonically dispersed at a frequency of 80kHz for 20 minutes. Then, 30% of the mass of the calcined material was added to the mixture, and the mixture was heated and stirred at 80℃ for 120 minutes to obtain the pretreated calcined material dispersion. By weight, take 110 parts of pretreated calcined material dispersion, 8 parts of bifunctional acrylate resin, 1.2 parts of photoinitiator 2-hydroxy-2-methyl-1-phenylpropanone, and 8 parts of cosolvent isoamyl acetate. First, emulsify the emulsion by stirring at 600 r / min for 30 min at room temperature, and then emulsify it by ultrasonication at 70 kHz for 15 min to obtain a stable emulsion. The stable emulsion was continuously injected into the reactor at a rate of 10 mL / min and irradiated with a 365 nm UV-LED lamp for 20 min for UV curing. After centrifugation, washing, drying and sieving were performed to obtain spherical clay particles. Among them, the spherical clay particles are selected with a particle size distribution range of 10-30nm; sphericity of 0.95; and surface coating to achieve a Mohs hardness of 1. Substrate layer raw material preparation: By weight, take 70 parts polyvinyl alcohol, 12 parts polyethylene glycol, 8 parts sodium alginate, 10 parts glycerin, and 12 parts spherical clay particles. The polyvinyl alcohol has a degree of alcoholysis of 89%, an average degree of polymerization of 2500, and a weight-average molecular weight of 124000. The polyethylene glycol is selected from PEG 1000; Preparation of adhesive layer materials: By weight, take 55 parts sodium carboxymethyl cellulose and 35 parts hydroxyethyl cellulose; Preparation of substrate layer: Polyvinyl alcohol and water are mixed and dissolved to obtain a polyvinyl alcohol solution with a mass fraction of 20%. Polyethylene glycol, sodium alginate and glycerin were added to a polyvinyl alcohol solution and stirred at 600 r / min for 2 h. Spherical clay particles were then added and ultrasonically dispersed at 75 ℃ and 200 kHz for 2 h to obtain a substrate coating solution. After the substrate coating liquid is applied, it is transferred to an oven and dried at 70°C for 4 hours to obtain a substrate layer with a thickness of 80μm. Preparation of the adhesive layer: Sodium carboxymethyl cellulose and hydroxyethyl cellulose are dissolved in water, wherein the mass of water is 10 times the total mass of sodium carboxymethyl cellulose and hydroxyethyl cellulose; to obtain a binder layer solution. An adhesive layer solution is applied to the surface of a substrate layer and then dried at 70°C to a constant weight to obtain a substrate loaded with an adhesive layer, wherein the thickness of the adhesive layer is 1.0 times the thickness of the substrate layer. complex: The substrate with the adhesive layer is rolled and laminated under a pressure of 3.5 MPa and a temperature of 55°C, and then cut to obtain an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape.

[0025] Example 4 The difference between this embodiment and Embodiment 1 is as follows: Since the spherical clay particles were not coated with polyacrylate, their Mohs hardness differs from that of Example 1. Specifically, the Mohs hardness of this example is 4. The remaining conditions remain basically unchanged.

[0026] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: The size distribution range of the spherical clay particles is 10-30 nm; the sphericity is 0.85, and the other conditions remain basically unchanged.

[0027] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: The size distribution range of the spherical clay particles is 1-100 nm; the sphericity is 0.9, and the other conditions remain basically unchanged.

[0028] The performance tests conducted on the products obtained in the examples and comparative examples are as follows: The specific test methods and test results are described below: The product obtained from the above embodiments or comparative examples was used as a sample. The sample size was selected as 150mm*25mm. The bonding strength of the sample was tested and evaluated in accordance with the reference standard: ASTM D3330. The bonding strength was tested before the aging test, after 48 hours of aging test, and after 168 hours of aging test. The specific test results are shown in Table 1. The aging test should be conducted using the following method: The samples were placed in an accelerated aging test chamber with constant temperature and humidity, and placed at 85℃ / 85% RH for the corresponding time. Table 1: Product Performance Test Results As can be seen from the test results in Table 1, the adhesive tape products obtained by the method of the present invention have a relatively higher retention rate of adhesive strength in the damp heat aging test, which can effectively extend the service life of the products during the damp heat aging process.

[0029] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An environmentally friendly, biodegradable, water-soluble PVA encapsulation tape, characterized in that, Includes a substrate layer and an adhesive layer; The substrate layer comprises the following raw materials in parts by weight: 60-70 parts polyvinyl alcohol, 10-12 parts polyethylene glycol, 6-8 parts sodium alginate, 5-10 parts glycerol, and 10-12 parts spherical clay particles. The particle size distribution range of the spherical clay particles is 10-30 nm; Furthermore, the sphericity of the spherical clay particles is 0.9-0.95; The adhesive layer comprises the following raw materials in parts by weight: 45-55 parts sodium carboxymethyl cellulose and 25-35 parts hydroxyethyl cellulose.

2. The environmentally friendly, biodegradable, water-soluble PVA encapsulation tape according to claim 1, characterized in that, The spherical clay particles have a Mohs hardness of 1-2.

3. The environmentally friendly, biodegradable, water-soluble PVA encapsulation tape according to any one of claims 1 or 2, characterized in that, The surface of the spherical clay particles includes a buffer layer composed of polyacrylate.

4. The environmentally friendly, biodegradable, water-soluble PVA encapsulation tape according to claim 1, characterized in that, The thickness of the substrate layer is 60-80 μm; the thickness of the adhesive layer is 0.8-1.0 times the thickness of the substrate layer.

5. The environmentally friendly, biodegradable, water-soluble PVA encapsulation tape according to claim 4, characterized in that, The polyvinyl alcohol has a degree of alcoholysis of 87-89%, an average degree of polymerization of 2400-2500, and a weight-average molecular weight of 118000-124000.

6. The environmentally friendly, biodegradable, water-soluble PVA encapsulation tape according to claim 4, characterized in that, The polyethylene glycol is selected from any one of PEG 400, PEG 600, and PEG 1000.

7. A method for preparing an environmentally friendly, biodegradable, water-soluble PVA encapsulating tape as described in any one of claims 1-6, characterized in that, The specific preparation steps include: Prepare each component according to the raw material composition; Preparation of substrate layer: Polyvinyl alcohol and water are mixed and dissolved to obtain a polyvinyl alcohol solution with a mass fraction of 10-20%. Polyethylene glycol, sodium alginate and glycerin were added to a polyvinyl alcohol solution and stirred until homogeneous. Then, spherical clay particles were added and ultrasonically dispersed until homogeneous to obtain a substrate coating solution. The substrate coating liquid is applied and then dried to obtain the substrate layer; Preparation of the adhesive layer: Sodium carboxymethyl cellulose and hydroxyethyl cellulose are dissolved in water, wherein the mass of water is 8-10 times the total mass of sodium carboxymethyl cellulose and hydroxyethyl cellulose; to obtain a binder layer solution. The adhesive layer solution is applied to the surface of the substrate layer and then dried to obtain a substrate loaded with the adhesive layer. complex: The substrate with the adhesive layer is rolled and laminated, and then cut to obtain an environmentally friendly, biodegradable, water-soluble PVA encapsulation tape.

8. The method for preparing an environmentally friendly, biodegradable, water-soluble PVA encapsulating tape according to claim 7, characterized in that, The preparation steps of the spherical clay particles include: Montmorillonite was acid-washed with hydrochloric acid and then washed with deionized water until neutral to obtain impurity-free montmorillonite. Subsequently, the impurity-removed montmorillonite was dispersed in an ethanol solution, and 25-30% by weight of hexadecyltrimethylammonium bromide was added. After microwave ultrasonic reaction, the mixture was filtered, washed, and dried to obtain intercalated modified montmorillonite. Intercalated modified montmorillonite was ultrasonically dispersed in water and extruded through a 0.2-0.3 μm filter membrane to obtain clay sol. Ammonia was then added to the sol to adjust the pH to 9.2-9.

6. After standing for 3-6 hours to gel, the sol was spray-granulated to obtain spherical particles. Spherical particles are heated to 400-450℃, kept at that temperature and calcined, then sieved and graded to obtain spherical clay particles.

9. The method for preparing an environmentally friendly, biodegradable, water-soluble PVA encapsulating tape according to claim 8, characterized in that, The preparation steps of the spherical clay particles also include: The spherical particles are heated to 400-450℃ and calcined for a period of time to obtain the calcined material. After mixing the calcined material and water at a mass ratio of 1:80, the mixture is ultrasonically dispersed. Then, 20-30% of the mass of the calcined material is added to the mixture. The mixture is heated and stirred at 70-80℃ for 80-120 minutes to obtain a pretreated calcined material dispersion. By weight, take 100-110 parts of the pretreated calcined material dispersion, 6-8 parts of the bifunctional acrylate resin, 1-1.2 parts of the photoinitiator 2-hydroxy-2-methyl-1-phenylpropanone, and 6-8 parts of the cosolvent isoamyl acetate. First, stir and emulsify at room temperature, and then ultrasonically emulsify at an ultrasonic frequency of 60-70 kHz for 10-15 min to obtain a stable emulsion. The stable emulsion was continuously injected into the reactor at a rate of 10 mL / min and irradiated with a 365 nm UV-LED lamp for 15-20 min for UV curing. After centrifugation, the emulsion was washed, dried, and sieved to obtain spherical clay particles.

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