Light conversion BOPP pre-coating film and preparation method thereof

Abstract

The invention discloses a light conversion BOPP pre-coating film and a preparation method thereof, and belongs to the technical field of BOPP pre-coating films. The preparation method comprises the following steps: compounding the PE layer on the surface of one side of the prime-coat-free biaxially oriented polypropylene film to form the base material layer; performing corona treatment on the surface of the PE layer; performing melt extrusion on an ethylene-vinyl acetate polymer, and compounding the ethylene-vinyl acetate polymer to the surface of the PE layer through a tape casting method to form a hot melt adhesive layer; carrying out corona treatment on the surface of the hot melt adhesive layer; the method comprises the following steps: respectively dissolving Eu salt, Sm salt and Y salt in absolute ethyl alcohol, and mixing the obtained three solutions to obtain a mixed solution; dissolving salicylic acid and phenanthroline in absolute ethyl alcohol, and dropwise adding NaOH to adjust the pH value to 7 to obtain a ligand; adding the ligand into the mixed solution for reaction; and finally performing cooling, suction filtration, washing and drying treatment to obtain the light conversion material. Mixing and uniformly stirring a light conversion material, an organic solvent and water to obtain a light conversion material coating liquid; and coating the light conversion material coating liquid on the surface of the hot melt adhesive layer after corona treatment, and drying to obtain the light conversion BOPP pre-coating film.

Description

Technical Field

[0001] The invention belongs to the technical field of BOPP pre-coating films, and in particular relates to a light-converting BOPP pre-coating film and a preparation method thereof. Background Art

[0002] Pre-coated film is a BOPP (biaxially oriented polypropylene film) with a special surface coating, which is widely used in the packaging industry. It has good protection performance, transparency, glossiness and excellent printing performance. By coating the surface with hot melt adhesive, it can be combined with other films by simply heating and pressing. BOPP pre-coated film is widely used in food packaging, pharmaceutical packaging, daily necessities packaging, printing packaging and other fields. It has good moisture-proof, oxygen-barrier and moisture-barrier properties, which is conducive to protecting products from the influence of the external environment.

[0003] In the field of modern agriculture, with the continuous advancement of science and technology, various new agricultural materials have emerged. Among them, light-converting film, as an innovative greenhouse film material, is gradually becoming an important role in greenhouse planting, flower cultivation and agricultural production. In the process of plant production, ultraviolet light, green light and yellow light in sunlight have little effect on plant growth or are even not conducive to plant growth. For this reason, a light-converting BOPP pre-coated film is proposed. Summary of the invention

[0004] In view of the deficiencies in the prior art, the object of the present invention is to provide a light-converting BOPP pre-coated film and a preparation method thereof, which solves the problems in the prior art.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for preparing a light-converting BOPP pre-coated film comprises the following steps:

[0007] S1, a PE layer is laminated on one side of the unprimed biaxially oriented polypropylene film to form a substrate layer;

[0008] S2, corona treatment of the surface of the PE layer;

[0009] S3, melt-extrude the ethylene-vinyl acetate polymer and compound it onto the surface of the PE layer of the biaxially oriented polypropylene film by a casting method to form a hot melt adhesive layer;

[0010] S4, after trimming and thickness measurement, performing corona treatment on the surface of the hot melt adhesive layer;

[0011] S5, dissolving Eu salt, Sm salt and Y salt in anhydrous ethanol respectively, and mixing the three solutions to obtain a mixed solution; then dissolving salicylic acid and o-phenanthroline in anhydrous ethanol, and adjusting the pH to 7 by dropping NaOH to obtain a ligand; then adding the ligand to the mixed solution for reaction; finally, cooling, filtering, washing and drying to obtain a light conversion material;

[0012] S6, mixing the light conversion material, the organic solvent and water and stirring them evenly to obtain a light conversion material coating liquid;

[0013] S7, coating the light-converting material coating liquid on the surface of the hot melt adhesive layer after the corona treatment and drying it to obtain the light-converting BOPP pre-coated film.

[0014] Furthermore, in S5, the molar ratio of Eu salt, Sm salt and Y salt is x:y:0.1, and x+y+0.1=1.

[0015] Furthermore, the thickness of the substrate layer is 12-14 μm; the thickness of the hot melt adhesive layer is 10-12 μm.

[0016] Furthermore, the molecular weight content of vinyl acetate in the ethylene-vinyl acetate polymer is 10%-20%.

[0017] Furthermore, in S3, the temperature of the melt extrusion is 200-210°C.

[0018] Furthermore, in S2, the power of the corona treatment is 7-9 W / m 2 ; In S4, the power of corona treatment is 10-12W / m 2 .

[0019] Furthermore, in S6, the mass ratio of the light conversion material, the organic solvent and water is (0.0.5-0.08):(100-200):(10-50).

[0020] Furthermore, the organic solvent is selected from one or more of chloroform, dichloromethane, acetone, ethyl acetate, tetrahydrofuran, benzene, toluene, acetonitrile, methanol and ethanol.

[0021] Further, in S7, drying is performed in an oven, the exhaust rate of the oven is 10%-30%, and the oven temperature is 40° C.;

[0022] A light-converting BOPP pre-coated film is prepared using the above-mentioned preparation method.

[0023] Beneficial effects of the present invention:

[0024] The present invention solves the technical problem of converting sunlight by pre-coating films in the prior art. The prepared pre-coating film can convert sunlight in the sun, not only having a wonderful color change, but also promoting plant growth, and has good agricultural practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 It is the fluorescence emission spectrum diagram of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] A light-converting BOPP pre-coated film, comprising from bottom to top a substrate layer, a hot-melt adhesive layer and a light-converting layer; the thickness of the substrate layer is 12-14 μm; the thickness of the hot-melt adhesive layer is 10-12 μm;

[0029] The substrate layer includes: a primer-free biaxially oriented polypropylene film and a PE layer laminated on one side of the primer-free biaxially oriented polypropylene film;

[0030] The raw material of the hot melt adhesive layer includes ethylene-vinyl acetate polymer; wherein the molecular weight content of vinyl acetate (VA) in the ethylene-vinyl acetate polymer is 10%-20%.

[0031] The light-conversion layer is formed by coating a light-conversion material coating liquid on the surface of the hot-melt adhesive layer; wherein the light-conversion material coating liquid comprises: a light-conversion material, an organic solvent and water, and the mass ratio is: (0.05-0.08): (100-200): (10-50);

[0032] The light-converting material is a light-converting agent of a rare earth organic complex doped with a variety of rare earth ions (Sm3+, Eu3+), and the ligands are salicylic acid and o-phenanthroline with strong coordination ability.

[0033] The organic solvent is selected from one or more of chloroform, dichloromethane, acetone, ethyl acetate, tetrahydrofuran, benzene, toluene, acetonitrile, methanol and ethanol.

[0034] The following examples are used to illustrate the preparation process of the light-converting BOPP pre-coated film. The sources of the raw materials in the examples are as follows:

[0035] Primer-free biaxially oriented polypropylene film: HPC12 produced by Anhui Guofeng New Materials Co., Ltd.;

[0036] Ethylene-vinyl acetate polymer: The content of vinyl acetate is 18%.

[0037] Example 1

[0038] The method for preparing the light-converting BOPP pre-coated film comprises the following steps:

[0039] S1, a PE layer is laminated on one side of the unprimed biaxially oriented polypropylene film to form a substrate layer; wherein the thickness of the substrate layer is 12 um;

[0040] S2, high-frequency and high-voltage corona treatment is performed on the surface of the PE layer, and the corona power is 7kW;

[0041] S3, melt-extrude ethylene-vinyl acetate polymer at 200° C. through a single-screw extruder, and compound it onto the surface of the PE layer of the biaxially oriented polypropylene film by a casting method to form a hot melt adhesive layer with a thickness of 10 μm;

[0042] S4, after trimming and thickness measurement, the surface of the hot melt adhesive layer is subjected to high frequency and high voltage corona treatment, with a corona power of 10KW.

[0043] S5, preparing light conversion material; the specific process is:

[0044] 1) Dissolve 0.1mmol of EuCl36H2O in 20mL of anhydrous ethanol as solution 1, 0.8mmol of SmCl3·6H2O in 20mL of anhydrous ethanol as solution 2, and 0.1mmol of YCl3·6H2O in 20mL of anhydrous ethanol as solution 3, where x represents Eu 3+ The molar amount of Sm 3+ The molar amount, Y 3+ The fixed molar amount is 0.1, and the molar ratio always follows the ratio of x+y+0.1=1. In this embodiment, x=0.1, y=0.8.

[0045] 2) Mix the prepared solutions 1, 2 and 3 in turn and stir them evenly, then pour them into a three-necked flask and heat them at 65°C for 0.5h. Dissolve salicylic acid (Hsal) and o-phenanthroline (Phen) in anhydrous ethanol and adjust the pH to 7 by dropping NaOH. The molar ratio of the two ligands of salicylic acid (Hsal) and o-phenanthroline is 3:1. After 0.5h, add the ligands to the three-necked flask at a uniform speed for reaction. After reacting at 75°C for 5h, a white precipitate appears. After the reaction is completed, cool it naturally to room temperature. Filter through a Buchner funnel, wash with ethanol, and dry in an oven at 100°C for 1h to obtain the light conversion material (Eu0.1Sm0.8Y0.1(Hsal)3Phen);

[0046] S6, mixing the light conversion material, the organic solvent (ethanol) and water in a mass ratio of 0.05:100:10 and stirring evenly to obtain a light conversion material coating liquid;

[0047] S7, coating the light-converting material coating liquid on the surface of the hot melt adhesive after corona treatment and using an oven to dry the film to obtain a light-converting BOPP pre-coated film; wherein the oven temperature is 40° C. and the oven exhaust rate is 10%.

[0048] Example 2

[0049] The method for preparing the light-converting BOPP pre-coated film comprises the following steps:

[0050] S1, a PE layer is laminated on one side of the unprimed biaxially oriented polypropylene film to form a substrate layer; wherein the thickness of the substrate layer is 14 μm;

[0051] S2, high-frequency and high-voltage corona treatment is performed on the surface of the PE layer, and the corona power is 9kW;

[0052] S3, melt-extrude ethylene-vinyl acetate polymer through a single-screw extruder at 210° C., and compound it onto the surface of the PE layer of the biaxially oriented polypropylene film through a casting method to form a hot melt adhesive layer with a thickness of 12 μm;

[0053] S4, after trimming and thickness measurement, the surface of the hot melt adhesive layer is subjected to high frequency and high voltage corona treatment, and the corona power is 12KW.

[0054] S5, preparing light conversion material; the specific process is:

[0055] 1) Dissolve 0.2mmol of EuCl36H2O in 20mL of anhydrous ethanol as solution 1, 0.7mmol of SmCl3·6H2O in 20mL of anhydrous ethanol as solution 2, and 0.1mmol of YCl3·6H2O in 20mL of anhydrous ethanol as solution 3, where x represents Eu 3+ The molar amount of Sm 3+The molar amount, Y 3+ The fixed molar amount is 0.1, and the molar ratio always follows the ratio of x+y+0.1=1. In this embodiment, x=0.2, y=0.7.

[0056] 2) Mix the prepared solutions 1, 2 and 3 in turn and stir them evenly, then pour them into a three-necked flask and heat them at 65°C for 0.5h. Dissolve salicylic acid (Hsal) and o-phenanthroline (Phen) in anhydrous ethanol and adjust the pH to 7 by dropping NaOH. The molar ratio of the two ligands of salicylic acid (Hsal) and o-phenanthroline is 3:1. After 0.5h, add the ligands to the three-necked flask at a uniform speed for reaction. After reacting at 75°C for 5h, a white precipitate appears. After the reaction is completed, cool it naturally to room temperature. Filter through a Buchner funnel, wash with ethanol, and dry in an oven at 100°C for 1h to obtain the light conversion material (Eu0.2Sm0.7Y0.1(Hsal)3Phen);

[0057] S6, mixing the light conversion material, the organic solvent (ethanol) and water in a mass ratio of 0.08:200:50 and stirring evenly to obtain a light conversion material coating liquid;

[0058] S7, coating the light-converting material coating liquid on the surface of the hot melt adhesive after corona treatment and using an oven to dry the film to obtain a light-converting BOPP pre-coated film; wherein the oven temperature is 40° C. and the oven exhaust rate is 30%.

[0059] Comparative Example 1

[0060] A method for preparing a BOPP pre-coated film specifically comprises the following steps:

[0061] S1, a PE layer is laminated on one side of the unprimed biaxially oriented polypropylene film to form a substrate layer; wherein the thickness of the substrate layer is 12 um;

[0062] S2, high-frequency and high-voltage corona treatment is performed on the surface of the PE layer, and the corona power is 9kW;

[0063] S3, melt-extrude ethylene-vinyl acetate polymer at 210° C., and compound it onto the surface of the PE layer of the biaxially oriented polypropylene film by a casting method to form a hot melt adhesive layer with a thickness of 10 μm;

[0064] S4, after trimming and thickness measurement, the surface of the hot melt adhesive layer is subjected to high frequency and high voltage corona treatment, with a corona power of 12KW, to obtain a BOPP pre-coated film.

[0065] Experimental testing

[0066] The BOPP pre-coated films prepared in Examples 1-2 and Comparative Examples were tested by UV spectrophotometer. The test results are as follows: Figure 1 As shown:

[0067] Figure 1 The fluorescence emission spectra of Examples 1 and 2 are shown. The light-converting agricultural film 1 is prepared in Example 1, and the light-converting agricultural film 2 is prepared in Example 2. It can be seen from the figure that the fluorescence emission spectrum has strong fluorescence emission peaks at 615 and 650nm, and has a good match with the absorption spectrum of plant photosynthesis in the red light region. Therefore, the light-converting agricultural film can effectively convert ultraviolet light into red light and promote plant growth.

[0068] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0069] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a light-converting BOPP pre-coating film, characterized in that: The following steps are involved: S1, a PE layer is laminated on one surface of a primer-free biaxially oriented polypropylene film to form a substrate layer; S2, corona treatment of the surface of the PE layer; S3, melt-extrude the ethylene-vinyl acetate polymer and compound it onto the surface of the PE layer of the biaxially oriented polypropylene film by a casting method to form a hot melt adhesive layer; S4, after trimming and thickness measurement, performing corona treatment on the surface of the hot melt adhesive layer; S5, dissolving Eu salt, Sm salt and Y salt in anhydrous ethanol respectively, and mixing the three solutions to obtain a mixed solution; then dissolving salicylic acid and o-phenanthroline in anhydrous ethanol, and adjusting the pH to 7 by dropping NaOH to obtain a ligand; then adding the ligand to the mixed solution for reaction; finally, cooling, filtering, washing and drying to obtain a light conversion material; S6, mixing the light conversion material, the organic solvent and water and stirring them evenly to obtain a light conversion material coating liquid; S7, coating the light-converting material coating liquid on the surface of the hot melt adhesive layer after the corona treatment and drying it to obtain the light-converting BOPP pre-coated film.

2. The method for preparing a light-converting BOPP pre-coating film according to claim 1, characterized in that: In S5, the molar ratio of Eu salt, Sm salt and Y salt is x:y:0.1, and x+y+0.1=1.

3. The method for preparing a light-converting BOPP pre-coating film according to claim 1, characterized in that: The thickness of the substrate layer is 12-14 μm; the thickness of the hot melt adhesive layer is 10-12 μm.

4. The method for preparing a light-converting BOPP pre-coating film according to claim 1, characterized in that: The molecular weight content of vinyl acetate in ethylene-vinyl acetate polymer is 10%-20%.

5. The method for preparing a light-converting BOPP pre-coating film according to claim 1, characterized in that: In S3, the temperature of melt extrusion is 200-210°C.

6. The method for preparing a light-converting BOPP pre-coating film according to claim 1, characterized in that: In S2, the power of corona treatment is 7-9W / m 2 ; In S4, the power of corona treatment is 10-12W / m 2 .

7. The method for preparing a light-converting BOPP pre-coating film according to claim 1, characterized in that: In S6, the mass ratio of the light conversion material, the organic solvent and water is (0.0.5-0.08):(100-200):(10-50).

8. The method for preparing a light-converting BOPP pre-coating film according to claim 7, characterized in that: The organic solvent is selected from one or more of chloroform, dichloromethane, acetone, ethyl acetate, tetrahydrofuran, benzene, toluene, acetonitrile, methanol and ethanol.

9. The method for preparing a light-converting BOPP pre-coating film according to claim 1, characterized in that: In S7, an oven is used for drying, the exhaust rate of the oven is 10%-30%, and the oven temperature is 40°C.

10. A light-converting BOPP pre-coated film, characterized in that: It is prepared using the preparation method described in any one of claims 1 to 9.

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