Polypropylene synthetic paper with glossy surface and matte surface and preparation method thereof

Abstract

The invention discloses a polypropylene synthetic paper with a bright surface and a matte surface and a preparation method thereof, which relates to the technical field of synthetic paper preparation, and is a three-layer co-extruded synthetic paper, which comprises a bright surface layer, a substrate layer and a matte surface layer from top to bottom; the substrate layer comprises the following raw materials by weight: 80-85 parts of modified polypropylene, 10-15 parts of filler; the matte surface layer comprises the following raw materials by weight: 80-85 parts of modified polypropylene, 5-10 parts of polyethylene, 1-3 parts of flame retardant, 1-3 parts of antistatic agent, 0.5-1 parts of matte flour, 0.5-1 parts of oleic acid amide lubricant and 5-10 parts of filler. The synthesized modified polypropylene contains a hindered phenol structure, a thioether group and a pyridine ring, which improves the antioxidant and antibacterial properties of the synthetic paper. The synthesized flame retardant has a macromolecular network structure, including a DOPO structure, a melamine structure and a long chain of cardanol alkane, which improves the flame retardancy, waterproofness and environmental protection of the synthetic paper.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic paper preparation, and in particular to a polypropylene synthetic paper with a glossy surface and a matte surface and a preparation method thereof. Background Art

[0002] Polypropylene synthetic paper is made of polypropylene as raw material and some additives. It has the advantages of good environmental performance, low specific gravity, corrosion resistance, and good printability. It is widely used in the printing of high-end artworks, maps, picture albums, high-end books and periodicals, etc.

[0003] The polypropylene synthetic paper in the prior art has poor antioxidant and UV resistance. If the printed work is exposed outdoors for a long time, it will fade seriously. Polypropylene and other polyolefin materials used in polypropylene synthetic paper are easy to burn, which is not conducive to the storage and transportation of synthetic paper. Some polypropylene synthetic papers used in special occasions such as label synthetic paper also need to have antibacterial properties. Patent application number 201910371664.1 discloses a matte synthetic paper with advantages such as high surface haze, low gloss, and excellent printability, but still has the following shortcomings: (1) The antioxidant used is a small molecule organic compound, which is directly added to the matrix and has poor compatibility and dispersibility with polymers, etc., and is easy to migrate and fail; (2) The invention does not mention the flame retardant and antibacterial properties of synthetic paper. In addition, in actual use, the decomposition time of discarded synthetic paper is very long, and its biodegradability is poor, which causes great harm to the environment.

[0004] Therefore, it is urgent and important to conduct in-depth research on the preparation technology of polypropylene synthetic paper in order to develop polypropylene synthetic paper with better performance to meet higher usage requirements. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a polypropylene synthetic paper with a glossy surface and a matte surface.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A polypropylene synthetic paper with a glossy surface and a matte surface is a three-layer co-extruded synthetic paper, which comprises a glossy surface layer, a base material layer and a matte surface layer from top to bottom; the base material layer comprises the following raw materials in parts by weight: 80-85 parts of modified polypropylene and 10-15 parts of a filler; the glossy surface layer is made of isotactic polypropylene; the matte surface layer comprises the following raw materials in parts by weight: 80-85 parts of modified polypropylene, 5-10 parts of polyethylene, 1-3 parts of a flame retardant, 1-3 parts of an antistatic agent, 0.5-1 parts of matte flour, 0.5-1 parts of a lubricant and 5-10 parts of a filler; the antistatic agent is polyethylene oxide; the matte flour is prepared by mixing talcum powder, silicon dioxide and barium sulfate in a mass ratio of 3:1:2, the talcum powder has a particle size of 5-7 μm, the silicon dioxide has a particle size of 8-10 μm, and the barium sulfate has a particle size of 1-2 μm; the lubricant is oleic acid amide;

[0008] The filler is prepared by mixing nano calcium carbonate modified by silane coupling agent and nano titanium dioxide modified by silane coupling agent in a mass ratio of 2:1; the preparation process of nano calcium carbonate modified by silane coupling agent is as follows: nano calcium carbonate is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 7.5 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 50°C to obtain nano calcium carbonate modified by silane coupling agent; the preparation process of nano titanium dioxide modified by silane coupling agent is as follows: nano titanium dioxide is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 8.0 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 55°C to obtain nano titanium dioxide modified by silane coupling agent; the volume fraction of ethanol is 95%, and the concentration of sodium hydroxide solution is 0.1 mol / L;

[0009] The preparation of the polypropylene synthetic paper with a glossy surface and a matte surface comprises the following steps:

[0010] Step S1: the isotactic polypropylene used for the bright surface layer and the modified polypropylene, polyethylene, antistatic agent, flame retardant, matte flour, lubricant and filler used for the matte surface layer are stirred for 10-15 minutes through the feeding port of the single-screw auxiliary extruder, and then respectively enter the single-screw auxiliary extruder, and are extruded into a T-die after being mixed and evacuated; the modified polypropylene and filler used for the base material layer are mixed and evacuated in the twin-screw main extruder at 130-140° C., and then extruded into the T-die, and the co-extruded multilayer is cooled and formed by a cooling roller and a water tank, and is formed into a laminated sheet at 40° C.;

[0011] Step S2: The laminated sheet is introduced into a stretching device, preheated, stretched and tempered at 110-120°C, stretched 4 times in the longitudinal direction and 6 times in the transverse direction, and then corona treated with a high-frequency wave with a power of 60-80kW to obtain a polypropylene synthetic paper with a thickness of 80-100μm and a glossy and matte surface.

[0012] The modified polypropylene is prepared by the following steps:

[0013] Step A1: 3,5-di-tert-butyl-4-hydroxybenzoic acid is added to DMF, and dichlorothionyl is added under stirring, and the mixture is refluxed and stirred at 50° C. for 4-5 hours to obtain an acyl chloride product; 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate and dimethyl sulfoxide are added to a flask to obtain a mixed solution a, and then the above-mentioned acyl chloride product is added to dimethyl sulfoxide to obtain a mixed solution b, and the mixed solution b is slowly added dropwise to the mixed solution a in an ice-water bath at 0° C. After the addition is completed, the mixture is heated to 40° C., stirred at a constant temperature for 8-10 hours, and distilled under reduced pressure to obtain an amide product;

[0014] Further, the dosage ratio of 3,5-di-tert-butyl-4-hydroxybenzoic acid, DMF, and dichlorothionyl is 0.1 mol: 55-65 mL: 0.12-0.15 mol; the dosage ratio of 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.004-0.006 mol: 45-55 mL; the dosage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 65-75 mL; the dosage ratio of the mixed solution a and the mixed solution b is 50-60 mL: 70-80 mL;

[0015] During the reaction of step A1, the carboxyl group of 3,5-di-tert-butyl-4-hydroxybenzoic acid reacts with thionyl chloride to generate an acyl chloride product; the acyl chloride of the acyl chloride product reacts with the secondary amino group of 1-(3-nitropyridin-2-yl)piperazine to obtain a nitro-containing amide product;

[0016] Step A2: Add the amide product and ethyl acetate into a three-necked flask, heat to 45°C, start reflux stirring, then add sodium dithionite, and reflux stirring for 1 hour to obtain the amino product;

[0017] Further, the usage ratio of the amide product, ethyl acetate, and sodium dithionite is 0.1 mol: 125-135 mL: 0.12-0.15 mol;

[0018] During the reaction of step A2, the nitro group of the amide product is reduced to an amino group to obtain an amino product;

[0019] Step A3: Add 2-(allylthio)acetic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 60° C. for 3-4 hours to obtain sulfuryl chloride; add the amino product, potassium carbonate and dimethyl sulfoxide to a flask to obtain a mixed solution c, and then add the above sulfuryl chloride to dimethyl sulfoxide to obtain a mixed solution d, slowly drop the mixed solution d into the mixed solution c in an ice-water bath at 0° C. After the dropwise addition is completed, the temperature is raised to 40° C., stirred at a constant temperature for 7-9 hours, and distilled under reduced pressure to obtain a functional monomer;

[0020] Further, the dosage ratio of 2-(allylthio)acetic acid, DMF, and dichlorothionyl is 0.1 mol: 30-40 mL: 0.12-0.15 mol; the dosage ratio of amino product, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.007-0.009 mol: 135-145 mL; the dosage ratio of sulfuryl chloride and dimethyl sulfoxide is 0.1 mol: 40-50 mL; the dosage ratio of mixed solution c and mixed solution d is 140-150 mL: 45-55 mL;

[0021] During the reaction of step A3, the carboxyl group of 2-(allylthio)acetic acid reacts with thionyl chloride to generate sulfuryl chloride; the sulfuryl chloride reacts with the amino group of the amino product to obtain a functional monomer containing hindered phenol and thioether group;

[0022] Step A4: In a nitrogen atmosphere, toluene, functional monomers and crosslinking agents were added to the reaction bottle, stirred for 15-25 minutes, and then isotactic polypropylene was added and stirred for 10-15 minutes. The reaction bottle was sealed and then 60 After irradiation with Coγ-rays for 8-10 hours, the isotactic polypropylene is taken out, washed with anhydrous ethanol, extracted with acetone, and dried to obtain modified polypropylene;

[0023] Further, the usage ratio of toluene, functional monomer, crosslinking agent, and isotactic polypropylene is 300-350 mL: 10-15 g: 7-9 g: 100-110 g, and the crosslinking agent is divinylbenzene;

[0024] During the reaction of step A4, 60 Under the irradiation of Coγ-rays and the assistance of a cross-linking agent, the functional monomer is grafted onto the isotactic polypropylene to obtain modified polypropylene.

[0025] The flame retardant is prepared by the following steps:

[0026] Step B1: Add a dicarboxylic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 60°C for 3-4h to obtain an acyl chloride product a; add cardanol, pyridine, triethylamine and dimethyl sulfoxide to a flask to obtain a mixed solution 1; add the acyl chloride product a to dimethyl sulfoxide to obtain a mixed solution 2, slowly drop the mixed solution 2 into the mixed solution 1 in a 0°C ice-water bath, after the dropwise addition is completed, heat to 40°C, stir at a constant temperature for 8-10h, then heat to 105-115°C, continue stirring for 1-2h, and then distill under reduced pressure to obtain an esterification product;

[0027] Further, the usage ratio of dicarboxylic acid, DMF and dichlorothionyl is 0.1 mol: 75-85 mL: 0.13-0.17 mol, and the dicarboxylic acid is [(6-oxo-6H-dibenzo[C,E][1,2]oxaphosphorin-6-yl)methyl]succinic acid; the usage ratio of cardanol, pyridine, triethylamine and dimethyl sulfoxide is 0.2 mol: 0.01-0.015 mol: 0.2 mol: 125-135 mL, and the cardanol is cardanol (C15: 1); the usage ratio of acyl chloride product a and dimethyl sulfoxide is 0.1 mol: 80-90 mL; the usage ratio of mixed solution 1 and mixed solution 2 is 130-140 mL: 85-95 mL;

[0028] During the reaction of step B1, the carboxyl group of the dicarboxylic acid reacts with thionyl chloride to generate an acyl chloride product a; the phenolic hydroxyl group of cardanol reacts with the acyl chloride product a to generate an esterification product containing a carbon-carbon double bond;

[0029] Step B2: Add the esterification product to dichloromethane, start stirring, then add 3-chloroperbenzoic acid, and stir at room temperature for 4-5 hours to obtain the epoxy product;

[0030] Further, the usage ratio of the esterification product, dichloromethane and 3-chloroperoxybenzoic acid is 0.1 mol: 220-230 mL: 0.2 mol;

[0031] During the reaction of step B2, the carbon-carbon double bond in the esterification product is oxidized into an epoxy group to obtain an epoxy product;

[0032] Step B3: In a nitrogen atmosphere, add 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and toluene into a flask, heat to 45°C, add pyridine, start stirring, add the epoxy product into the flask, stir and react for 8-10h, then heat to 105-115°C, stir for 1-2h, and obtain a flame retardant;

[0033] Further, the ratio of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine, toluene, pyridine and epoxy product is 47-51 g: 310-320 mL: 0.08-0.10 mol: 96-100 g;

[0034] During the reaction of step B3, the carboxyl group of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine reacts with the epoxy group of the epoxy product to form a flame retardant having a macromolecular network structure, a long chain of cardanol-based alkane, and the like.

[0035] Beneficial effects of the invention: The invention discloses a polypropylene synthetic paper with a glossy surface and a matte surface, which is a three-layer co-extruded synthetic paper, which comprises a glossy surface layer, a base material layer and a matte surface layer from top to bottom; the base material layer comprises the following raw materials: modified polypropylene and a filler; the matte surface layer comprises the following raw materials: modified polypropylene, polyethylene, a flame retardant, an antistatic agent, matte flour, a lubricant and a filler.

[0036] The synthesized modified polypropylene includes hindered phenol structure, thioether group, carbon-carbon double bond and pyridine ring in the molecule; the hindered phenol structure generates hydroperoxide in the oxidative degradation reaction of the polymer to terminate the oxidative degradation reaction, while the thioether group can reduce and decompose the hydroperoxide, and the hindered phenol structure and the thioether group produce rapid intramolecular synergy to prevent the polymer oxidation reaction from continuing, and graft with isotactic polypropylene under the action of radiation, so that the dispersion compatibility in the matrix is ​​better, and the disadvantage of small molecule migration failure is avoided; when microorganisms contact synthetic paper, the pyridine ring interacts with multiple biological molecules such as ribosomes, DNA, RNA and membranes in the microbial cells, interferes with their normal physiological metabolism and cell structure, thereby causing bacterial death, and has a broad spectrum of bactericidal properties, can prevent the generation of drug resistance, and make the synthetic paper have excellent antibacterial properties; adding the synthesized modified polypropylene makes the synthetic paper have good antioxidant and antibacterial properties.

[0037] The synthesized flame retardant has a macromolecular network structure, a long chain of cardanol alkane, a DOPO structure, a melamine structure, etc. The long chain of cardanol alkane and the macromolecular network structure increase the compatibility and dispersibility of the flame retardant with modified polypropylene and polyethylene, which is more conducive to the performance of the flame retardant. The DOPO structure can dehydrate and degrade the burning surface of the polymer to form a carbon layer when the matrix burns, and the phosphorus-containing derivatives produced at the same time cover the surface of the polymer, isolate the combustible gas, block the heat transfer, form a physical shield, and prevent the combustion from continuing. Melamine The structure can undergo a sublimation endothermic reaction at high temperatures, reduce the surface temperature of the polymer, and delay the speed at which the synthetic paper reaches its decomposition temperature. The sublimated melamine and the nitrogen-containing non-combustible gas generated by combustion dilute the combustible gas, preventing the combustion reaction from continuing. It can also promote the rapid carbonization of the material to form a carbon layer with a honeycomb structure that is heat-insulating and oxygen-insulating, and produce a synergistic flame-retardant effect with DOPO in the molecule; the cardanol used in the synthetic flame retardant is biodegradable, and the long chain of the cardanol-based alkane is also highly hydrophobic, which improves the waterproofness and environmental protection of the synthetic paper. Adding the synthesized flame retardant can improve the flame retardancy, waterproofness and environmental protection of the synthetic paper. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0039] Embodiment 1: A modified polypropylene, the preparation of which comprises the following steps:

[0040] Step A1: Add 3,5-di-tert-butyl-4-hydroxybenzoic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 50°C for 4 hours to obtain an acyl chloride product; add 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate and dimethyl sulfoxide to a flask to obtain a mixed solution a, and then add the above-mentioned acyl chloride product to dimethyl sulfoxide to obtain a mixed solution b. In a 0°C ice-water bath, slowly drop the mixed solution b into the mixed solution a. After the dropwise addition is completed, the temperature is raised to 40°C, and the reaction is stirred at a constant temperature for 8 hours. , distill under reduced pressure to obtain the amide product; the usage ratio of 3,5-di-tert-butyl-4-hydroxybenzoic acid, DMF, and dichlorothionyl is 0.1 mol: 55 mL: 0.12 mol; the usage ratio of 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.004 mol: 45 mL; the usage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 65 mL; the usage ratio of the mixed solution a and the mixed solution b is 50 mL: 70 mL;

[0041] Step A2: Add the amide product and ethyl acetate into a three-necked flask, heat to 45°C, start reflux stirring, then add sodium dithionite, and reflux stirring for 1 hour to obtain the amino product; the dosage ratio of the amide product, ethyl acetate, and sodium dithionite is 0.1 mol: 125 mL: 0.12 mol;

[0042] Step A3: Add 2-(allylthio)acetic acid to DMF, add dichlorothionyl under stirring, and react under reflux stirring at 60° C. for 3 h to obtain sulfuryl chloride; add the amino product, potassium carbonate and dimethyl sulfoxide to a flask to obtain a mixed solution c, then add the above sulfuryl chloride to dimethyl sulfoxide to obtain a mixed solution d, slowly drop the mixed solution d into the mixed solution c in an ice-water bath at 0° C. After the dropwise addition is completed, the mixture is heated to 40° C., stirred at a constant temperature for 7 h, and distilled under reduced pressure to obtain a functional monomer; the amount ratio of 2-(allylthio)acetic acid, DMF, and dichlorothionyl is 0.1 mol: 30 mL: 0.12 mol; the amount ratio of the amino product, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.007 mol: 135 mL; the amount ratio of sulfuryl chloride and dimethyl sulfoxide is 0.1 mol: 40 mL; the amount ratio of mixed solution c to mixed solution d is 140 mL: 45 mL;

[0043] Step A4: In a nitrogen atmosphere, toluene, functional monomers and crosslinking agents were added to the reaction bottle, stirred for 15 min, isotactic polypropylene was added and stirred for 10 min, the reaction bottle was sealed, and then 60 After 8 hours of Coγ-ray irradiation, the isotactic polypropylene was taken out and rinsed with anhydrous ethanol, extracted with acetone, and dried to obtain modified polypropylene; the usage ratio of toluene, functional monomer, crosslinking agent, and isotactic polypropylene was 300mL:10g:7g:100g, and the crosslinking agent was divinylbenzene.

[0044] Embodiment 2: A modified polypropylene, the preparation of which comprises the following steps:

[0045] Step A1: 3,5-di-tert-butyl-4-hydroxybenzoic acid was added to DMF, and dichlorothionyl was added under stirring, and the mixture was refluxed and stirred at 50°C for 4.5 hours to obtain an acyl chloride product; 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate and dimethyl sulfoxide were added to a flask to obtain a mixed solution a, and then the above-mentioned acyl chloride product was added to dimethyl sulfoxide to obtain a mixed solution b. In a 0°C ice-water bath, the mixed solution b was slowly added dropwise to the mixed solution a. After the addition was completed, the temperature was raised to 40°C and the mixture was stirred at a constant temperature for 9 hours. h, distill under reduced pressure to obtain the amide product; the usage ratio of 3,5-di-tert-butyl-4-hydroxybenzoic acid, DMF, and dichlorothionyl is 0.1 mol: 60 mL: 0.13 mol; the usage ratio of 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.005 mol: 50 mL; the usage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 70 mL; the usage ratio of the mixed solution a and the mixed solution b is 55 mL: 75 mL;

[0046] Step A2: Add the amide product and ethyl acetate into a three-necked flask, heat to 45°C, start reflux stirring, then add sodium dithionite, and reflux stirring for 1 hour to obtain the amino product; the dosage ratio of the amide product, ethyl acetate, and sodium dithionite is 0.1 mol: 130 mL: 0.13 mol;

[0047] Step A3: Add 2-(allylthio)acetic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 60°C for 3.5h to obtain sulfuryl chloride; add the amino product, potassium carbonate and dimethyl sulfoxide to a flask to obtain a mixed solution c, and then add the above sulfuryl chloride to dimethyl sulfoxide to obtain a mixed solution d. In a 0°C ice-water bath, slowly drop the mixed solution d into the mixed solution c. After the dropwise addition is completed, the temperature is raised to 40°C, and the reaction is stirred at the constant temperature for 8h. , distill under reduced pressure to obtain the functional monomer; the usage ratio of 2-(allylthio)acetic acid, DMF, and dichlorothionyl is 0.1mol:35mL:0.14mol; the usage ratio of amino product, potassium carbonate, and dimethyl sulfoxide is 0.1mol:0.008mol:140mL; the usage ratio of sulfuryl chloride and dimethyl sulfoxide is 0.1mol:45mL; the usage ratio of mixed solution c and mixed solution d is 145mL:50mL;

[0048] Step A4: In a nitrogen atmosphere, toluene, functional monomers and crosslinking agents were added to the reaction bottle, stirred for 20 min, isotactic polypropylene was added and stirred for 13 min, the reaction bottle was sealed, and then 60 After irradiation with Coγ rays for 9 hours, the isotactic polypropylene was taken out and rinsed with anhydrous ethanol, extracted with acetone and dried to obtain modified polypropylene; the dosage ratio of toluene, functional monomer, crosslinking agent and isotactic polypropylene was 320mL:13g:8g:105g, and the crosslinking agent was divinylbenzene.

[0049] Embodiment 3: A modified polypropylene, the preparation of which comprises the following steps:

[0050] Step A1: Add 3,5-di-tert-butyl-4-hydroxybenzoic acid to DMF, add dichlorothionyl under stirring, and reflux and stir at 50°C for 5 hours to obtain an acyl chloride product; add 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate and dimethyl sulfoxide to a flask to obtain a mixed solution a, and then add the above-mentioned acyl chloride product to dimethyl sulfoxide to obtain a mixed solution b. In a 0°C ice-water bath, slowly drop the mixed solution b into the mixed solution a. After the dropwise addition is completed, the temperature is raised to 40°C and stirred at a constant temperature for 10 hours. , distill under reduced pressure to obtain the amide product; the usage ratio of 3,5-di-tert-butyl-4-hydroxybenzoic acid, DMF, and dichlorothionyl is 0.1mol: 65mL: 0.15mol; the usage ratio of 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate, and dimethyl sulfoxide is 0.1mol: 0.006mol: 55mL; the usage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1mol: 75mL; the usage ratio of the mixed solution a and the mixed solution b is 60mL: 80mL;

[0051] Step A2: Add the amide product and ethyl acetate into a three-necked flask, heat to 45°C, start reflux stirring, then add sodium dithionite, and reflux stirring for 1 hour to obtain the amino product; the dosage ratio of the amide product, ethyl acetate, and sodium dithionite is 0.1 mol: 135 mL: 0.15 mol;

[0052] Step A3: Add 2-(allylthio)acetic acid to DMF, add dithionyl chloride under stirring, and react under reflux stirring at 60° C. for 4 hours to obtain sulfuryl chloride; add the amino product, potassium carbonate and dimethyl sulfoxide to a flask to obtain a mixed solution c, then add the above sulfuryl chloride to dimethyl sulfoxide to obtain a mixed solution d, slowly drop the mixed solution d into the mixed solution c in an ice-water bath at 0° C. After the dropwise addition is completed, the mixture is heated to 40° C. and stirred at a constant temperature for 9 hours, and distilled under reduced pressure to obtain a functional monomer; the amount ratio of 2-(allylthio)acetic acid, DMF, and dithionyl chloride is 0.1 mol: 40 mL: 0.15 mol; the amount ratio of the amino product, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.009 mol: 145 mL; the amount ratio of sulfuryl chloride and dimethyl sulfoxide is 0.1 mol: 50 mL; the amount ratio of mixed solution c to mixed solution d is 150 mL: 55 mL;

[0053] Step A4: In a nitrogen atmosphere, toluene, functional monomers and crosslinking agent were added to the reaction bottle, stirred for 25 min, isotactic polypropylene was added and stirred for 15 min, the reaction bottle was sealed, and then 60 After 10 hours of Coγ-ray irradiation, the isotactic polypropylene was taken out and rinsed with anhydrous ethanol, extracted with acetone, and dried to obtain modified polypropylene; the usage ratio of toluene, functional monomer, cross-linking agent, and isotactic polypropylene was 350mL:15g:9g:110g, and the cross-linking agent was divinylbenzene.

[0054] Embodiment 4: A flame retardant, the preparation of which comprises the following steps:

[0055] Step B1: Add a dicarboxylic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 60°C for 3h to obtain an acyl chloride product a; add cardanol, pyridine, triethylamine and dimethyl sulfoxide to a flask to obtain a mixed solution 1; add the acyl chloride product a to dimethyl sulfoxide to obtain a mixed solution 2, slowly drop the mixed solution 2 into the mixed solution 1 in a 0°C ice water bath, after the dropwise addition is completed, heat to 40°C, stir at a constant temperature for 8h, then heat to 105°C, continue stirring for 1h, and then distill under reduced pressure to obtain an esterification product; dicarboxylic acid, DMF, thionyl chloride The dosage ratio of is 0.1mol:75mL:0.13mol, the dicarboxylic acid is [(6-oxo-6H-dibenzo[C,E][1,2]oxaphosphorin-6-yl)methyl]succinic acid; the dosage ratio of cardanol, pyridine, triethylamine and dimethyl sulfoxide is 0.2mol:0.01mol:0.2mol:125mL, the cardanol is cardanol (C15:1); the dosage ratio of acyl chloride product a and dimethyl sulfoxide is 0.1mol:80mL; the dosage ratio of mixed solution 1 and mixed solution 2 is 130mL:85mL;

[0056] Step B2: Add the esterification product to dichloromethane, start stirring, then add 3-chloroperoxybenzoic acid, and stir at room temperature for 4 hours to obtain the epoxidation product; the amount ratio of the esterification product, dichloromethane and 3-chloroperoxybenzoic acid is 0.1 mol: 220 mL: 0.2 mol;

[0057] Step B3: In a nitrogen atmosphere, add 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine and toluene to a flask, heat to 45°C, add pyridine, start stirring, add the epoxy product to the flask, stir and react for 8 hours, then heat to 105°C, stir for 1 hour to obtain a flame retardant; the amount ratio of 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine, toluene, pyridine and epoxy product is 47g:310mL:0.08mol:96g.

[0058] Embodiment 5: A flame retardant, the preparation of which comprises the following steps:

[0059] Step B1: Add the dicarboxylic acid to DMF, add dichlorothionyl under stirring, and reflux and stir at 60°C for 3.5h to obtain the acyl chloride product a; add cardanol, pyridine, triethylamine and dimethyl sulfoxide to a flask to obtain a mixed solution 1; add the acyl chloride product a to dimethyl sulfoxide to obtain a mixed solution 2, slowly drop the mixed solution 2 into the mixed solution 1 in a 0°C ice-water bath, after the dropwise addition is completed, heat to 40°C, stir at a constant temperature for 9h, then heat to 110°C, continue stirring for 1.5h, and then distill under reduced pressure to obtain an esterification product; dicarboxylic acid, DMF, dichlorothionyl The amount ratio of sulfone is 0.1mol:80mL:0.15mol, the dicarboxylic acid is [(6-oxo-6H-dibenzo[C,E][1,2]oxaphosphorin-6-yl)methyl]succinic acid; the amount ratio of cardanol, pyridine, triethylamine and dimethyl sulfoxide is 0.2mol:0.013mol:0.2mol:130mL, the cardanol is cardanol (C15:1); the amount ratio of acyl chloride product a and dimethyl sulfoxide is 0.1mol:85mL; the amount ratio of mixed solution 1 and mixed solution 2 is 135mL:90mL;

[0060] Step B2: Add the esterification product to dichloromethane, start stirring, then add 3-chloroperoxybenzoic acid, and stir at room temperature for 4.5 hours to obtain the epoxidation product; the amount ratio of the esterification product, dichloromethane and 3-chloroperoxybenzoic acid is 0.1 mol: 225 mL: 0.2 mol;

[0061] Step B3: In a nitrogen atmosphere, add 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine and toluene to a flask, heat to 45°C, add pyridine, start stirring, add the epoxy product to the flask, stir and react for 9 hours, then heat to 110°C, stir for 1.5 hours to obtain a flame retardant; the amount ratio of 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine, toluene, pyridine and epoxy product is 49g:315mL:0.09mol:98g.

[0062] Embodiment 6: A flame retardant, the preparation of which comprises the following steps:

[0063] Step B1: Add a dicarboxylic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 60°C for 4 hours to obtain an acyl chloride product a; add cardanol, pyridine, triethylamine and dimethyl sulfoxide to a flask to obtain a mixed solution 1; add the acyl chloride product a to dimethyl sulfoxide to obtain a mixed solution 2, slowly drop the mixed solution 2 into the mixed solution 1 in a 0°C ice water bath, after the dropwise addition is completed, heat to 40°C, stir at a constant temperature for 10 hours, then heat to 115°C, continue stirring for 2 hours, and then distill under reduced pressure to obtain an esterification product; dicarboxylic acid, DMF, thionyl chloride The dosage ratio of is 0.1mol:85mL:0.17mol, the dicarboxylic acid is [(6-oxo-6H-dibenzo[C,E][1,2]oxaphosphorin-6-yl)methyl]succinic acid; the dosage ratio of cardanol, pyridine, triethylamine and dimethyl sulfoxide is 0.2mol:0.015mol:0.2mol:135mL, the cardanol is cardanol (C15:1); the dosage ratio of acyl chloride product a and dimethyl sulfoxide is 0.1mol:90mL; the dosage ratio of mixed solution 1 and mixed solution 2 is 140mL:95mL;

[0064] Step B2: Add the esterification product to dichloromethane, start stirring, then add 3-chloroperoxybenzoic acid, stir and react at room temperature for 5 hours to obtain the epoxidation product; the amount ratio of the esterification product, dichloromethane and 3-chloroperoxybenzoic acid is 0.1 mol: 230 mL: 0.2 mol;

[0065] Step B3: In a nitrogen atmosphere, add 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine and toluene to a flask, heat to 45°C, add pyridine, start stirring, add the epoxy product to the flask, stir and react for 10 hours, then heat to 115°C, stir for 2 hours to obtain a flame retardant; the amount ratio of 2,4,6-tris(aminohexanoic acid)-1,3,5-triazine, toluene, pyridine and epoxy product is 51g:320mL:0.10mol:100g.

[0066] Embodiment 7: A polypropylene synthetic paper with a glossy surface and a matte surface is a three-layer co-extruded synthetic paper, which comprises a glossy surface layer, a base material layer and a matte surface layer from top to bottom; the base material layer comprises the following raw materials in parts by weight: 80 parts of modified polypropylene and 10 parts of filler; the glossy surface layer is made of isotactic polypropylene; the matte surface layer comprises the following raw materials in parts by weight: 80 parts of modified polypropylene, 5 parts of polyethylene, 1 part of flame retardant, 1 part of antistatic agent, 0.5 parts of matte flour, 0.5 parts of lubricant and 5 parts of filler; the antistatic agent is polyethylene oxide; the matte flour is a mixture of talcum powder, silicon dioxide and barium sulfate in a mass ratio of 3:1:2, the talcum powder has a particle size of 5 μm, the silicon dioxide has a particle size of 8 μm, and the barium sulfate has a particle size of 1 μm; the lubricant is oleic acid amide;

[0067] The filler is prepared by mixing nano calcium carbonate modified by silane coupling agent and nano titanium dioxide modified by silane coupling agent in a mass ratio of 2:1; the preparation process of nano calcium carbonate modified by silane coupling agent is as follows: nano calcium carbonate is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 7.5 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 50°C to obtain nano calcium carbonate modified by silane coupling agent; the preparation process of nano titanium dioxide modified by silane coupling agent is as follows: nano titanium dioxide is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 8.0 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 55°C to obtain nano titanium dioxide modified by silane coupling agent; the volume fraction of ethanol is 95%, and the concentration of sodium hydroxide solution is 0.1 mol / L;

[0068] The preparation of the polypropylene synthetic paper with a glossy surface and a matte surface comprises the following steps:

[0069] Step S1: the isotactic polypropylene used for the bright surface layer and the modified polypropylene, polyethylene, antistatic agent, flame retardant, matte flour, lubricant and filler used for the matte surface layer are stirred for 10 minutes through the feeding port of the single-screw auxiliary extruder, and then respectively enter the single-screw auxiliary extruder, and are extruded into a T-die after being mixed and evacuated; the modified polypropylene and filler used for the base material layer are mixed and evacuated in the twin-screw main extruder at 130° C., and then extruded into the T-die, and the co-extruded multilayer is cooled and formed by a cooling roller and a water tank, and is formed into a laminated sheet at 40° C.;

[0070] Step S2: The laminated sheet is introduced into a stretching device, preheated, stretched and tempered at 110°C, stretched 4 times in the longitudinal direction and 6 times in the transverse direction, and then corona treated with a high-frequency wave with a power of 60kW to obtain a polypropylene synthetic paper with a thickness of 80μm and a glossy and matte surface.

[0071] Embodiment 8: A polypropylene synthetic paper with a glossy surface and a matte surface is a three-layer co-extruded synthetic paper, which comprises a glossy surface layer, a base material layer and a matte surface layer from top to bottom; the base material layer comprises the following raw materials in parts by weight: 83 parts of modified polypropylene and 13 parts of filler; the glossy surface layer is made of isotactic polypropylene; the matte surface layer comprises the following raw materials in parts by weight: 83 parts of modified polypropylene, 8 parts of polyethylene, 2 parts of flame retardant, 2 parts of antistatic agent, 0.8 parts of matte flour, 0.8 parts of lubricant and 8 parts of filler; the antistatic agent is polyethylene oxide; the matte flour is a mixture of talcum powder, silicon dioxide and barium sulfate in a mass ratio of 3:1:2, the talcum powder has a particle size of 6 μm, the silicon dioxide has a particle size of 9 μm, and the barium sulfate has a particle size of 1 μm; the lubricant is oleic acid amide;

[0072] The filler is prepared by mixing nano calcium carbonate modified by silane coupling agent and nano titanium dioxide modified by silane coupling agent in a mass ratio of 2:1; the preparation process of nano calcium carbonate modified by silane coupling agent is as follows: nano calcium carbonate is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 7.5 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 50°C to obtain nano calcium carbonate modified by silane coupling agent; the preparation process of nano titanium dioxide modified by silane coupling agent is as follows: nano titanium dioxide is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 8.0 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 55°C to obtain nano titanium dioxide modified by silane coupling agent; the volume fraction of ethanol is 95%, and the concentration of sodium hydroxide solution is 0.1 mol / L;

[0073] The preparation of the polypropylene synthetic paper with a glossy surface and a matte surface comprises the following steps:

[0074] Step S1: the isotactic polypropylene used for the bright surface layer and the modified polypropylene, polyethylene, antistatic agent, flame retardant, matte flour, lubricant and filler used for the matte surface layer are stirred for 13 minutes through the feeding port of the single-screw auxiliary extruder, and then respectively enter the single-screw auxiliary extruder, and are extruded into a T-die after being mixed and evacuated; the modified polypropylene and filler used for the base material layer are mixed and evacuated in the twin-screw main extruder at 135° C., and then extruded into the T-die, and the co-extruded multilayer is cooled and formed by cooling rollers and water tanks, and is formed into a laminated sheet at 40° C.;

[0075] Step S2: The laminated sheet is introduced into a stretching device, preheated, stretched and tempered at 115°C, stretched 4 times in the longitudinal direction and 6 times in the transverse direction, and then corona treated with a high-frequency wave with a power of 70kW to obtain a polypropylene synthetic paper with a thickness of 90μm and a glossy and matte surface.

[0076] Embodiment 9: A polypropylene synthetic paper with a glossy surface and a matte surface is a three-layer co-extruded synthetic paper, which comprises a glossy surface layer, a base material layer and a matte surface layer from top to bottom; the base material layer comprises the following raw materials in parts by weight: 85 parts of modified polypropylene and 15 parts of filler; the glossy surface layer is made of isotactic polypropylene; the matte surface layer comprises the following raw materials in parts by weight: 85 parts of modified polypropylene, 10 parts of polyethylene, 3 parts of flame retardant, 3 parts of antistatic agent, 1 part of matte flour, 1 part of lubricant and 10 parts of filler; the antistatic agent is polyethylene oxide; the matte flour is a mixture of talcum powder, silicon dioxide and barium sulfate in a mass ratio of 3:1:2, the talcum powder has a particle size of 7 μm, the silicon dioxide has a particle size of 10 μm, and the barium sulfate has a particle size of 2 μm; the lubricant is oleic acid amide;

[0077] The filler is prepared by mixing nano calcium carbonate modified by silane coupling agent and nano titanium dioxide modified by silane coupling agent in a mass ratio of 2:1; the preparation process of nano calcium carbonate modified by silane coupling agent is as follows: nano calcium carbonate is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 7.5 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 50°C to obtain nano calcium carbonate modified by silane coupling agent; the preparation process of nano titanium dioxide modified by silane coupling agent is as follows: nano titanium dioxide is added to ethanol, ultrasonically dispersed for 30 minutes, and then the pH is adjusted to 8.0 with sodium hydroxide solution, and then dodecyl trimethoxy silane is added, and the temperature is raised to 55°C to obtain nano titanium dioxide modified by silane coupling agent; the volume fraction of ethanol is 95%, and the concentration of sodium hydroxide solution is 0.1 mol / L;

[0078] The preparation of the polypropylene synthetic paper with a glossy surface and a matte surface comprises the following steps:

[0079] Step S1: the isotactic polypropylene used for the bright surface layer and the modified polypropylene, polyethylene, antistatic agent, flame retardant, matte flour, lubricant and filler used for the matte surface layer are stirred for 15 minutes through the feeding port of the single-screw auxiliary extruder, and then respectively enter the single-screw auxiliary extruder, and are extruded into a T-die after being mixed and evacuated; the modified polypropylene and filler used for the base material layer are mixed and evacuated in the twin-screw main extruder at 140° C., and then extruded into the T-die, and the co-extruded multilayer is cooled and formed by a cooling roller and a water tank, and is formed into a laminated sheet at 40° C.;

[0080] Step S2: The laminated sheet is introduced into a stretching device, preheated, stretched and tempered at 120°C, stretched 4 times in the longitudinal direction and 6 times in the transverse direction, and then corona treated with a high-frequency wave with a power of 80kW to obtain a polypropylene synthetic paper with a thickness of 100μm and a glossy and matte surface.

[0081] Comparative Example 1: Compared with Example 9, the modified polypropylene is replaced with isotactic polypropylene, and the rest is exactly the same as Example 9 to obtain a polypropylene synthetic paper with a glossy surface and a matte surface;

[0082] Comparative Example 2: Compared with Example 9, the flame retardant was replaced with 2,4,6-tris(aminocaproic acid)-1,3,5-triazine, and the rest was completely the same as Example 9, to obtain a polypropylene synthetic paper with a glossy surface and a matte surface;

[0083] The polypropylene synthetic paper with a glossy surface and a matte surface prepared by the present invention is further tested for its effects, and the test results are as follows.

[0084] In order to test the polypropylene synthetic paper with glossy and matte surfaces prepared by the present invention, the polypropylene synthetic paper prepared by Examples 7-9 and Comparative Examples 1-2 was subjected to an aging test. The aging test method was carried out according to the method of GB / T16422.3-2014 "Plastic Laboratory Light Source Exposure Test Method". The polypropylene synthetic paper prepared by Examples 7-9 and Comparative Examples 1-2 of the present application and the aged polypropylene synthetic paper were respectively subjected to a tensile strength test according to the method of GB13002-91; the antibacterial property test was carried out with Escherichia coli and Staphylococcus aureus as the test bacteria according to GB / T31402-2015 "Plastic Surface Antibacterial Performance Test Method"; the oxygen index was measured according to GB / T2406.1-2008 "Determination of Combustion Behavior by Oxygen Index Method for Plastics"; the polypropylene synthetic paper samples prepared by Examples 7-9 and Comparative Examples 1-2 were placed in 2L of water and soaked at room temperature for 10 hours, and the surface conditions of the synthetic paper were observed. The results are recorded in Table 1;

[0085] Table 1: Test results

[0086]

[0087] According to the data in Table 1, the polypropylene synthetic paper with bright and matte surfaces prepared by the present invention has good antioxidant, antibacterial, flame retardant and waterproof properties. Comparison between Example 9 and Comparative Example 1 shows that the introduction of hindered phenol structure, thioether group and pyridine ring improves the antioxidant and antibacterial properties of polypropylene synthetic paper. Comparison between Example 9 and Comparative Example 2 shows that the introduction of DOPO structure and cardanol alkane long chain produces intramolecular synergistic flame retardant effect between DOPO structure and melamine structure, improving the flame retardant and waterproof properties of polypropylene synthetic paper.

[0088] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A polypropylene synthetic paper with a glossy surface and a matte surface, characterized in that: It is a three-layer co-extruded synthetic paper, which comprises a bright surface layer, a base material layer and a matte surface layer from top to bottom; the base material layer comprises the following raw materials by weight: 80-85 parts of modified polypropylene and 10-15 parts of filler; the bright surface layer is made of isotactic polypropylene; the matte surface layer comprises the following raw materials by weight: 80-85 parts of modified polypropylene, 5-10 parts of polyethylene, 1-3 parts of flame retardant, 1-3 parts of antistatic agent, 0.5-1 parts of matte flour, 0.5-1 parts of lubricant and 5-10 parts of filler; The modified polypropylene is prepared by the following steps: Step A1: 3,5-di-tert-butyl-4-hydroxybenzoic acid is added to DMF, and dichlorothionyl is added under stirring, and the mixture is refluxed and stirred at 50° C. for 4-5 hours to obtain an acyl chloride product; 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate and dimethyl sulfoxide are added to a flask to obtain a mixed solution a, and then the above-mentioned acyl chloride product is added to dimethyl sulfoxide to obtain a mixed solution b, and the mixed solution b is slowly added dropwise to the mixed solution a in an ice-water bath at 0° C. After the addition is completed, the mixture is heated to 40° C., stirred at a constant temperature for 8-10 hours, and distilled under reduced pressure to obtain an amide product; Step A2: Add the amide product and ethyl acetate into a three-necked flask, heat to 45°C, start reflux stirring, then add sodium dithionite, and reflux stirring for 1 hour to obtain the amino product; Step A3: Add 2-(allylthio)acetic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 60° C. for 3-4 hours to obtain sulfuryl chloride; add the amino product, potassium carbonate and dimethyl sulfoxide to a flask to obtain a mixed solution c, and then add the above sulfuryl chloride to dimethyl sulfoxide to obtain a mixed solution d, slowly drop the mixed solution d into the mixed solution c in an ice-water bath at 0° C. After the dropwise addition is completed, the temperature is raised to 40° C., stirred at a constant temperature for 7-9 hours, and distilled under reduced pressure to obtain a functional monomer; Step A4: In a nitrogen atmosphere, toluene, functional monomers and crosslinking agents were added to the reaction bottle, stirred for 15-25 minutes, and then isotactic polypropylene was added and stirred for 10-15 minutes. The reaction bottle was sealed and then 60 After irradiation with Coγ rays for 8-10 hours, the isotactic polypropylene is taken out, washed with anhydrous ethanol, extracted with acetone, and dried to obtain modified polypropylene.

2. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 1, characterized in that: In step A1, the usage ratio of 3,5-di-tert-butyl-4-hydroxybenzoic acid, DMF, and dichlorothionyl is 0.1 mol: 55-65 mL: 0.12-0.15 mol; the usage ratio of 1-(3-nitropyridin-2-yl)piperazine, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.004-0.006 mol: 45-55 mL; the usage ratio of the acyl chloride product and dimethyl sulfoxide is 0.1 mol: 65-75 mL; and the usage ratio of the mixed solution a and the mixed solution b is 50-60 mL: 70-80 mL.

3. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 1, characterized in that: In step A2, the usage ratio of the amide product, ethyl acetate and sodium dithionite is 0.1 mol: 125-135 mL: 0.12-0.15 mol; in step A4, the usage ratio of toluene, functional monomer, crosslinking agent and isotactic polypropylene is 300-350 mL: 10-15 g: 7-9 g: 100-110 g, and the crosslinking agent is divinylbenzene.

4. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 1, characterized in that: In step A3, the amount ratio of 2-(allylthio)acetic acid, DMF, and dichlorothionyl is 0.1 mol: 30-40 mL: 0.12-0.15 mol; the amount ratio of amino product, potassium carbonate, and dimethyl sulfoxide is 0.1 mol: 0.007-0.009 mol: 135-145 mL; the amount ratio of sulfuryl chloride and dimethyl sulfoxide is 0.1 mol: 40-50 mL; the amount ratio of mixed solution c and mixed solution d is 140-150 mL: 45-55 mL.

5. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 1, characterized in that: The flame retardant is prepared by the following steps: Step B1: Add a dicarboxylic acid to DMF, add thionyl chloride under stirring, and reflux and stir at 60°C for 3-4h to obtain an acyl chloride product a; add cardanol, pyridine, triethylamine and dimethyl sulfoxide to a flask to obtain a mixed solution 1; add the acyl chloride product a to dimethyl sulfoxide to obtain a mixed solution 2, slowly drop the mixed solution 2 into the mixed solution 1 in a 0°C ice-water bath, after the dropwise addition is completed, heat to 40°C, stir at a constant temperature for 8-10h, then heat to 105-115°C, continue stirring for 1-2h, and then distill under reduced pressure to obtain an esterification product; Step B2: Add the esterification product to dichloromethane, start stirring, then add 3-chloroperbenzoic acid, and stir at room temperature for 4-5 hours to obtain the epoxy product; Step B3: In a nitrogen atmosphere, add 2,4,6-tris(aminocaproic acid)-1,3,5-triazine and toluene into a flask, heat to 45°C, add pyridine, start stirring, add the epoxy product into the flask, stir to react for 8-10h, then heat to 105-115°C, stir for 1-2h to obtain a flame retardant.

6. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 5, characterized in that: In step B1, the usage ratio of dicarboxylic acid, DMF and thionyl chloride is 0.1 mol: 75-85 mL: 0.13-0.17 mol, the dicarboxylic acid is [(6-oxo-6H-dibenzo[C,E][1,2]oxaphosphorin-6-yl)methyl]succinic acid; the amount ratio of cardanol, pyridine, triethylamine and dimethyl sulfoxide is 0.2 mol: 0.01-0.015 mol: 0.2 mol: 125-135 mL, and the cardanol is cardanol (C15: 1); the amount ratio of acyl chloride product a and dimethyl sulfoxide is 0.1 mol: 80-90 mL; the amount ratio of mixed solution 1 and mixed solution 2 is 130-140 mL: 85-95 mL.

7. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 5, characterized in that: In step B2, the usage ratio of the esterification product, dichloromethane and 3-chloroperbenzoic acid is 0.1 mol: 220-230 mL: 0.2 mol.

8. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 5, characterized in that: In step B3, the usage ratio of 2,4,6-tris(aminocaproic acid)-1,3,5-triazine, toluene, pyridine and epoxy product is 47-51 g: 310-320 mL: 0.08-0.10 mol: 96-100 g.

9. The polypropylene synthetic paper with a glossy surface and a matte surface according to claim 1, characterized in that: The antistatic agent is polyethylene oxide; the matte powder is prepared by mixing talcum powder, silicon dioxide and barium sulfate in a mass ratio of 3:1:2, the talcum powder particle size is 5-7μm, the silicon dioxide particle size is 8-10μm, and the barium sulfate particle size is 1-2μm; the lubricant is oleic acid amide, and the filler is prepared by mixing nano calcium carbonate modified by a silane coupling agent and nano titanium dioxide modified by a silane coupling agent in a mass ratio of 2:

1.

10. The method for preparing polypropylene synthetic paper with a glossy surface and a matte surface according to claim 1, characterized in that: The steps include: Step S1: the isotactic polypropylene used for the bright surface layer and the modified polypropylene, polyethylene, antistatic agent, flame retardant, matte flour, lubricant and filler used for the matte surface layer are stirred for 10-15 minutes through the feeding port of the single-screw auxiliary extruder, and then respectively enter the single-screw auxiliary extruder, and are extruded into a T-die after being mixed and evacuated; the modified polypropylene and filler used for the base material layer are mixed and evacuated in the twin-screw main extruder at 130-140° C., and then extruded into the T-die, and the co-extruded multilayer is cooled and formed by a cooling roller and a water tank, and is formed into a laminated sheet at 40° C.; Step S2: The laminated sheet is introduced into a stretching device, preheated, stretched and tempered at 110-120°C, stretched 4 times in the longitudinal direction and 6 times in the transverse direction, and then corona treated with a high-frequency wave with a power of 60-80kW to obtain a polypropylene synthetic paper with a thickness of 80-100μm and a glossy and matte surface.

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