An epp impact-resistant packaging board and a method for producing the same

Abstract

This invention relates to the field of EPP material technology, specifically disclosing an EPP impact-resistant packaging board and its preparation method. This EPP impact-resistant packaging board comprises the following raw materials: polypropylene resin, rhein-modified eucommia gum, phosphorylated maifanite fiber, maleic anhydride-grafted EPDM rubber, a nucleating agent, and a surfactant. The rhein-modified eucommia gum is obtained by a ring-opening reaction between epoxidized eucommia gum and rhein. The phosphorylated maifanite fiber is a modified fiber obtained by reacting maifanite fiber with alkenyl groups grafted onto its surface with vinylphosphonic acid. This invention incorporates rhein-modified eucommia gum and phosphorylated maifanite fiber into the preparation process of the EPP packaging board, resulting in an EPP packaging board with excellent impact resistance, antibacterial properties, and flame retardant effects, meeting the needs of various environments and possessing a long service life.

Description

Technical Field

[0001] This invention relates to the field of EPP material technology, specifically to an EPP impact-resistant packaging board and its preparation method. Background Technology

[0002] Expanded polypropylene (EPP) is a high-performance crystalline polymer foam material with many advantages such as light weight, low temperature resistance, and corrosion resistance. It is widely used in logistics and transportation, precision instrument packaging, electronic and electrical protection, and automotive parts packaging. Compared with other traditional foam materials, EPP material has better structural stability and weather resistance, and can meet the basic protective packaging needs of conventional items. It is one of the core materials in the current cushioning packaging field.

[0003] With the rapid development of modern manufacturing, e-commerce logistics, and the precision electronics industry, the market has placed higher demands on the comprehensive protective performance, safety of use and transportation, and functional adaptability of packaging materials. High-end precision components, medical equipment, and other goods have intricate structures and are easily damaged by impacts, making them highly dependent on the impact resistance and cushioning capabilities of the packaging materials used. The complex environment of transportation and warehousing also requires additional properties such as antibacterial and flame retardant properties of packaging materials. However, ordinary EPP materials themselves have poor flame retardant properties, posing significant safety hazards during transportation and warehousing. Their matrix toughness is insufficient, and their impact resistance needs to be improved. At the same time, ordinary EPP materials do not have antibacterial capabilities, and the surface of the materials easily absorbs moisture and dust, breeding bacteria, mold, and other microorganisms. This not only contaminates the packaged goods but also affects the safety of products with high cleanliness requirements, such as medical supplies and food parts, greatly limiting the application scope of EPP packaging boards in special fields such as medical and food.

[0004] Patent CN115028881B discloses an EPP bead, a method for preparing EPP beads, and a molded part thereof. By activating glass fibers to participate in the preparation process of EPP material, a cage-like cross-linking system is generated within the system, which makes the prepared EPP material have excellent flame retardant properties and cushioning capacity, greatly improving the safety of EPP material use. However, the EPP material prepared by this patent does not have antibacterial effect, which limits its use in special fields such as medical and food. Summary of the Invention

[0005] The purpose of this invention is to provide an EPP impact-resistant packaging board and its preparation method, which solves the following technical problems: (1) Ordinary EPP packaging boards have poor toughness and impact-resistant buffering effect; (2) Ordinary EPP packaging boards do not have antibacterial ability and their application fields are limited; (3) Ordinary EPP packaging boards have poor flame retardant performance and pose safety hazards when used.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An EPP impact-resistant packaging board comprises the following raw materials in parts by weight: 80-100 parts polypropylene resin, 8-10 parts rhein-modified eucommia gum, 6-8 parts phosphorylated maifanite fiber, 5-6 parts maleic anhydride-grafted EPDM rubber, 1-3 parts nucleating agent, and 1-2 parts surfactant; wherein the rhein-modified eucommia gum is obtained by epoxidized eucommia gum and rhein through a ring-opening reaction; and the phosphorylated maifanite fiber is a modified fiber obtained by reacting maifanite fiber with alkenyl groups grafted on its surface with vinylphosphonic acid.

[0008] Furthermore, the nucleating agent is talc or calcium carbonate; the surfactant is any one of calcium stearate, zinc stearate, and ethylene bis-stearamide.

[0009] Furthermore, the preparation method of the rhein-modified Eucommia gum includes the following steps:

[0010] S1: Weigh out Eucommia ulmoides gum powder, add it to a three-necked round-bottom flask, add deionized water, heat to 50-55℃, stir for 1-2 hours, add glacial acetic acid and hydrogen peroxide dropwise while stirring, after reacting for 5-6 hours, add sodium carbonate, stir until no bubbles are generated, filter, wash with deionized water until neutral, and vacuum dry to obtain epoxidized Eucommia ulmoides gum;

[0011] S2: Place epoxidized Eucommia ulmoides gum in toluene, add rhein and catalyst, purge with nitrogen, heat to 90-100℃ and react for 8-10 hours. After cooling to room temperature, place the mixture in ethanol to precipitate, filter and wash with ethanol 3-5 times, vacuum dry and collect the product to obtain rhein-modified Eucommia ulmoides gum.

[0012] Through the above technical solution, under the action of glacial acetic acid and hydrogen peroxide, the double bonds in the Eucommia ulmoides gum structure are oxidized to form epoxy groups, resulting in epoxidized Eucommia ulmoides gum. Then, under the action of a catalyst, the carboxyl groups in the rhein structure undergo a ring-opening reaction with the epoxy groups in the epoxidized Eucommia ulmoides gum structure, resulting in rhein-modified Eucommia ulmoides gum. This rhein-modified Eucommia ulmoides gum structure contains active hydroxyl groups, which can interact with the anhydride groups in maleic anhydride-grafted EPDM rubber, significantly improving the interfacial compatibility between the rhein-modified Eucommia ulmoides gum and the polypropylene matrix. In addition, the rhein-modified Eucommia ulmoides gum structure contains anthraquinone rings and phenolic hydroxyl groups, which can endow the material with excellent antibacterial properties, effectively inhibiting bacterial growth on the surface of packaging boards and significantly expanding its application areas. Furthermore, the rigid anthraquinone rings can form a synergistic structure of rigidity and flexibility with the flexible Eucommia ulmoides gum segments, effectively enhancing the impact resistance of EPP packaging boards and extending their service life.

[0013] Furthermore, in step S1, the hydrogen peroxide has a mass fraction of 30-36%.

[0014] Further, in step S2, the catalyst is any one of tetrabutylammonium bromide, tetrabutylammonium chloride, and tetrabutylammonium hydroxide.

[0015] Furthermore, the preparation method of the phosphorylated maifanite fiber includes the following steps:

[0016] SS1: Place maifan stone fiber in toluene, ultrasonically disperse for 10-15 min, introduce nitrogen gas, add allyl isocyanate and dibutyltin dilaurate, reflux for 6-8 h, cool, filter, wash and vacuum dry to obtain allyl maifan stone fiber.

[0017] SS2: Allyl maifanite fiber is placed in N,N-dimethylformamide and ultrasonically dispersed for 15-20 min. Nitrogen gas is introduced, vinylphosphonic acid and initiator are added, the temperature is raised to 75-80℃, and the reaction is stirred for 8-10 h. After cooling, filtration, washing and vacuum drying, phosphorylated maifanite fiber is obtained.

[0018] Through the above technical solution, under the action of an organotin catalyst, the isocyanate groups in the allyl isocyanate structure react with the hydroxyl groups on the surface of maifanite fiber, grafting allyl groups onto the surface of maifanite fiber to obtain allyl maifanite fiber. Then, under the action of an initiator, the alkenyl groups on the surface of allyl maifanite fiber undergo a free radical polymerization reaction with the alkenyl groups in the vinylphosphonic acid structure to obtain phosphorylated maifanite fiber coated with phosphoric acid. The surface of this phosphorylated maifanite fiber contains phosphate groups, which have strong polarity and can interact with the polar modifiers in the polypropylene matrix, significantly improving the interaction between inorganic fibers and organic matrix. The interfacial bonding force between the matrix effectively prevents fiber aggregation and migration. At the same time, the introduction of maifan stone fiber can promote the formation of uniform and fine pores during the foaming process of EPP material. The fiber itself occupies space in the matrix material and can form voids after foaming. When the EPP packaging board is impacted, it can effectively stop the propagation of cracks and improve impact resistance. Furthermore, the phosphate groups on the surface of this phosphorylated maifan stone fiber can decompose at high temperature to produce polyphosphoric acid, promote char formation, and form a ceramic barrier layer between the fiber and the fiber, giving the packaging board excellent flame retardancy and effectively improving the impact resistance and safety of the EPP packaging board.

[0019] Furthermore, in step SS1, the length of the maifanite fiber is 50-150 μm and the diameter is 5-15 μm.

[0020] Furthermore, in step SS2, the initiator is either azobisisobutyronitrile or azobisisoheptanenitrile.

[0021] A method for preparing an EPP impact-resistant packaging board includes the following steps:

[0022] Step 1: Place polypropylene resin, rhein-modified eucommia gum, phosphorylated maifan stone fiber, maleic anhydride-grafted EPDM rubber, nucleating agent, and surfactant in a high-speed mixer and mix evenly. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 180-200℃ and the screw speed to 200-300rpm, melt extrude, cool, and granulate to obtain premixed granules.

[0023] Step 2: Transfer the premixed granules to a high-pressure autoclave, seal it, introduce CO2, heat to 155-165℃, pressurize to 10-12MPa, and after 2-2.5h, open the pressure relief valve and control the pressure relief rate to 1-1.2MPa / s to obtain EPP foamed beads.

[0024] Step 3: Fill the mold with EPP foam beads evenly, introduce steam at 0.4-0.5MPa, heat to 130-140℃, keep warm for 30-40s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP impact-resistant packaging board.

[0025] The beneficial effects of this invention are:

[0026] This invention incorporates rhein-modified Eucommia ulmoides gum and phosphorylated maifanite fiber into the preparation process of EPP packaging boards, resulting in EPP packaging boards with excellent impact resistance, antibacterial properties, and flame retardant effects, meeting the needs of various environments and having a long service life.

[0027] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating the preparation process of the EPP impact-resistant packaging board of the present invention. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The preparation methods of rhein-modified Eucommia ulmoides gum and phosphorylated maifanite fiber in the following embodiments and comparative examples of the present invention are as follows:

[0032] I. Preparation of rhein-modified Eucommia ulmoides gum

[0033] S1: Weigh 5g of Eucommia ulmoides gum powder and add it to a 100ml three-necked round-bottom flask. Add 50ml of deionized water, heat to 50℃, and stir for 1h. While stirring, add 2.2g of glacial acetic acid and 8.3g of 30% hydrogen peroxide dropwise. After reacting for 5h, add 1.8g of sodium carbonate and stir until no bubbles are generated. Filter and wash with deionized water until neutral. After vacuum drying, epoxidized Eucommia ulmoides gum is obtained.

[0034] S2: Place 4.8g of epoxidized Eucommia gum in 80ml of toluene, add 2g of rhein and 0.3g of tetrabutylammonium bromide, purge with nitrogen, heat to 90℃ and react for 8h. After cooling to room temperature, precipitate the mixture in ethanol, filter and wash with ethanol 3 times, vacuum dry and collect the product to obtain rhein-modified Eucommia gum.

[0035] The epoxy values ​​of epoxidized Eucommia ulmoides gum and rhein-modified Eucommia ulmoides gum were tested using the hydrochloric acid-acetone method. 1g of each was taken as a sample. The specific testing method was as follows: The sample was placed in a 250ml Erlenmeyer flask, 20ml of acetone was added, and the mixture was ultrasonically dispersed for 10min. Then, 0.5ml of concentrated hydrochloric acid was added, and the mixture was allowed to stand for 1h. Two drops of phenolphthalein indicator were added, and the solution was titrated with a 0.1mol / L sodium hydroxide solution until the solution changed color. A blank control was also performed. The epoxy value of the sample (mol / 100g) was calculated using the following formula: Epoxy value of sample (mol / 100g) = (V0 - V1) C / 10m; V0 is the volume of sodium hydroxide solution consumed by the blank sample, ml; V1 is the volume of sodium hydroxide solution consumed by the test sample, ml; C is the standard molar concentration of sodium hydroxide, mol / L; m is the sample mass, g; Calculations show that the epoxy value in epoxidized Eucommia ulmoides gum is 0.16 mol / 100g; the epoxy value in rhein-modified Eucommia ulmoides gum is 0.02 mol / 100g. The significant reduction in epoxy value in rhein-modified Eucommia ulmoides gum is due to the ring-opening reaction between the epoxy groups in the epoxidized Eucommia ulmoides gum structure and the carboxyl groups in the rhein structure.

[0036] II. Preparation of Phosphorylated Maifan Stone Fiber

[0037] SS1: 5g of maifan stone fibers with a length of 100μm and a diameter of 10μm were placed in 100ml of toluene, ultrasonically dispersed for 10min, nitrogen gas was introduced, 2g of allyl isocyanate and 0.05g of dibutyltin dilaurate were added, the mixture was heated to reflux and reacted for 6h, cooled, filtered, washed and vacuum dried to obtain allyl maifan stone fibers;

[0038] SS2: 5.3g of allyl maifanite fiber was placed in 120ml of N,N-dimethylformamide and ultrasonically dispersed for 15min. Nitrogen gas was introduced, and 3.4g of vinylphosphonic acid and 0.1g of azobisisobutyronitrile were added. The mixture was heated to 75℃ and stirred for 8h. After cooling, filtration, washing, and vacuum drying, phosphorylated maifanite fiber was obtained.

[0039] 1g of allyl maifanite fiber and 1g of phosphorylated maifanite fiber were taken as samples, and the double bond content in the samples was tested by iodometric titration. The specific detection method is as follows: Prepare a 0.1mol / L sodium thiosulfate solution, a 12% potassium iodide solution, and a 1.2% starch solution; place 20ml of carbon tetrachloride in an iodine flask, add the sample, add 8ml of bromine-potassium bromide solution, stir thoroughly, add 4ml of potassium iodide solution and 5ml of deionized water, stir evenly, and then titrate with sodium thiosulfate standard solution. When the solution color changes, add 1ml of starch solution and continue titrating to the reaction endpoint. A blank control was performed simultaneously. The following formula was used for calculation: Double bond content in the sample (%) = (V0-V)C×M / 20m; where V0 is the volume of sodium thiosulfate solution consumed in the blank test, ml; V is the volume of sodium thiosulfate solution consumed in the titration of the sample, ml; C is the concentration of sodium thiosulfate solution, mol / L; M is the molar mass of the double bond portion (g / mol); m is the sample mass, g; it was calculated that the double bond content in allyl maifanite fiber is 4.2%, and the double bond content in phosphorylated maifanite fiber is 1.3%. Compared with phosphorylated maifanite fiber, the decrease in double bond content is due to the consumption caused by the free radical polymerization reaction between the double bonds in allyl maifanite fiber and the alkenyl group in the vinylphosphonic acid structure.

[0040] Example 1

[0041] Preparation of EPP impact-resistant packaging board

[0042] Step 1: Mix 80 parts polypropylene resin, 8 parts rhein-modified eucommia gum, 6 parts phosphorylated maifan stone fiber, 5 parts maleic anhydride-grafted EPDM rubber, 1 part talc powder, and 1 part calcium stearate in a high-speed mixer until homogeneous. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 180℃ and the screw speed to 200 rpm, melt extrude, cool, and granulate to obtain premixed granules.

[0043] Step 2: Transfer the premixed particles to a high-pressure autoclave, seal it, introduce CO2, heat to 155℃, pressurize to 10MPa, and after 2 hours, open the pressure relief valve and control the pressure relief rate to 1MPa / s to obtain EPP foamed beads.

[0044] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.4MPa steam, heat to 130℃, keep warm for 30s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP impact-resistant packaging board.

[0045] Example 2

[0046] Preparation of EPP impact-resistant packaging board

[0047] Step 1: Mix 90 parts polypropylene resin, 9 parts rhein-modified eucommia gum, 7 parts phosphorylated maifanite fiber, 5.5 parts maleic anhydride-grafted EPDM rubber, 2 parts calcium carbonate, and 1.5 parts zinc stearate in a high-speed mixer until homogeneous. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 190℃ and the screw speed to 250 rpm, melt extrude, cool, and granulate to obtain premixed granules.

[0048] Step 2: Transfer the premixed particles to a high-pressure autoclave, seal it, introduce CO2, heat to 160℃, pressurize to 11MPa, and after 2.2 hours, open the pressure relief valve and control the pressure relief rate to 1.1MPa / s to obtain EPP foamed beads.

[0049] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.4MPa steam, heat to 135℃, keep warm for 35s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP impact-resistant packaging board.

[0050] Example 3

[0051] Preparation of EPP impact-resistant packaging board

[0052] Step 1: Mix 100 parts polypropylene resin, 10 parts rhein-modified eucommia gum, 8 parts phosphorylated maifan stone fiber, 6 parts maleic anhydride-grafted EPDM rubber, 3 parts talc powder, and 2 parts ethylene bis-stearamide in a high-speed mixer until homogeneous. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 200℃ and the screw speed to 300 rpm, melt extrude, cool, and granulate to obtain premixed granules.

[0053] Step 2: Transfer the premixed granules to a high-pressure autoclave, seal it, introduce CO2, heat to 165℃, pressurize to 12MPa, and after 2.5h, open the pressure relief valve and control the pressure relief rate to 1.2MPa / s to obtain EPP foamed beads.

[0054] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.5MPa steam, heat to 140℃, keep warm for 40s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP impact-resistant packaging board.

[0055] Comparative Example 1

[0056] Preparation of EPP Packaging Boards

[0057] Step 1: Mix 90 parts polypropylene resin, 7 parts phosphorylated maifanite fiber, 5.5 parts maleic anhydride-grafted EPDM rubber, 2 parts calcium carbonate, and 1.5 parts zinc stearate in a high-speed mixer until homogeneous. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 190℃ and the screw speed to 250 rpm, melt extrude, cool, and granulate to obtain premixed granules.

[0058] Step 2: Transfer the premixed particles to a high-pressure autoclave, seal it, introduce CO2, heat to 160℃, pressurize to 11MPa, and after 2.2 hours, open the pressure relief valve and control the pressure relief rate to 1.1MPa / s to obtain EPP foamed beads.

[0059] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.4MPa steam, heat to 135℃, keep warm for 35s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP packaging board.

[0060] Comparative Example 2

[0061] Preparation of EPP Packaging Boards

[0062] Step 1: Place 90 parts of polypropylene resin, 9 parts of rhein-modified eucommia gum, 5.5 parts of maleic anhydride-grafted EPDM rubber, 2 parts of calcium carbonate, and 1.5 parts of zinc stearate into a high-speed mixer and mix evenly. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 190℃ and the screw speed to 250 rpm, melt extrude, cool and granulate to obtain premixed granules.

[0063] Step 2: Transfer the premixed particles to a high-pressure autoclave, seal it, introduce CO2, heat to 160℃, pressurize to 11MPa, and after 2.2 hours, open the pressure relief valve and control the pressure relief rate to 1.1MPa / s to obtain EPP foamed beads.

[0064] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.4MPa steam, heat to 135℃, keep warm for 35s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP packaging board.

[0065] Comparative Example 3

[0066] Preparation of EPP Packaging Boards

[0067] Step 1: Mix 90 parts polypropylene resin, 9 parts epoxidized eucommia gum, 7 parts phosphorylated maifan stone fiber, 5.5 parts maleic anhydride grafted EPDM rubber, 2 parts calcium carbonate, and 1.5 parts zinc stearate in a high-speed mixer until homogeneous. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 190℃ and the screw speed to 250 rpm, melt extrude, cool, and granulate to obtain premixed granules.

[0068] Step 2: Transfer the premixed particles to a high-pressure autoclave, seal it, introduce CO2, heat to 160℃, pressurize to 11MPa, and after 2.2 hours, open the pressure relief valve and control the pressure relief rate to 1.1MPa / s to obtain EPP foamed beads.

[0069] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.4MPa steam, heat to 135℃, keep warm for 35s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP packaging board.

[0070] Comparative Example 4

[0071] Preparation of EPP Packaging Boards

[0072] Step 1: Mix 90 parts polypropylene resin, 9 parts rhubarb-modified eucommia gum, 7 parts allyl maifanite fiber, 5.5 parts maleic anhydride-grafted EPDM rubber, 2 parts calcium carbonate, and 1.5 parts zinc stearate in a high-speed mixer until homogeneous. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 190℃ and the screw speed to 250 rpm, melt extrude, cool, and granulate to obtain premixed granules.

[0073] Step 2: Transfer the premixed particles to a high-pressure autoclave, seal it, introduce CO2, heat to 160℃, pressurize to 11MPa, and after 2.2 hours, open the pressure relief valve and control the pressure relief rate to 1.1MPa / s to obtain EPP foamed beads.

[0074] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.4MPa steam, heat to 135℃, keep warm for 35s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP packaging board.

[0075] Comparative Example 5

[0076] Preparation of EPP Packaging Boards

[0077] Step 1: Place 90 parts of polypropylene resin, 9 parts of rhein-modified eucommia gum, 7 parts of phosphorylated maifanite fiber, 2 parts of calcium carbonate, and 1.5 parts of zinc stearate into a high-speed mixer and mix evenly. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 190℃ and the screw speed to 250 rpm, melt extrude, cool and granulate to obtain premixed granules.

[0078] Step 2: Transfer the premixed particles to a high-pressure autoclave, seal it, introduce CO2, heat to 160℃, pressurize to 11MPa, and after 2.2 hours, open the pressure relief valve and control the pressure relief rate to 1.1MPa / s to obtain EPP foamed beads.

[0079] Step 3: Fill the mold with EPP foam beads evenly, introduce 0.4MPa steam, heat to 135℃, keep warm for 35s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP packaging board.

[0080] Performance testing

[0081] The EPP packaging boards prepared in Examples 1-3 and Comparative Examples 1-5 were made into samples that met the specifications. The oxygen index of the samples was tested according to standard GB / T2406.2-2009 to determine their flame retardancy; the antibacterial rate was tested according to standard GB / T31402-2023; the tensile strength and elongation at break were tested according to standard GB / T6344-2008 to determine their toughness and impact resistance; and the maximum dynamic cushioning stress was tested according to standard GB / T8167-2008. The specific test results are shown in the table below:

[0082]

[0083] As shown in the table above, the EPP impact-resistant packaging boards prepared in Examples 1-3 of this invention are significantly superior to the comparative examples in five key performance aspects: oxygen index, antibacterial rate, tensile strength, elongation at break, and maximum dynamic buffer stress. The sample prepared in Comparative Example 1 lacks rhein-modified Eucommia ulmoides gum, resulting in a poor antibacterial rate and moderate toughness. Comparative Example 2 lacks phosphorylated maifanite fiber, leading to significantly insufficient flame retardant performance. The sample prepared in Comparative Example 3 uses epoxidized Eucommia ulmoides gum without rhein grafting, resulting in poor antibacterial ability. The sample prepared in Comparative Example 4 uses allyl maifanite fiber, resulting in poor flame retardant ability. Comparative Example 5 does not contain maleic anhydride-grafted EPDM rubber, resulting in varying degrees of reduction in all properties. The above data indicate that there is a synergistic effect between rhein-modified Eucommia ulmoides gum, phosphorylated maifanite fiber, and maleic anhydride-grafted EPDM rubber in this invention, significantly enhancing the overall performance of the EPP packaging board.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0085] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. An EPP impact-resistant packaging board, characterized in that, The raw materials include the following parts by weight: 80-100 parts polypropylene resin, 8-10 parts rhein-modified eucommia gum, 6-8 parts phosphorylated maifanite fiber, 5-6 parts maleic anhydride-grafted EPDM rubber, 1-3 parts nucleating agent, and 1-2 parts surfactant; wherein the rhein-modified eucommia gum is obtained by epoxidized eucommia gum and rhein through a ring-opening reaction; wherein the phosphorylated maifanite fiber is a modified fiber obtained by reacting maifanite fiber with alkenyl groups grafted on its surface with vinylphosphonic acid.

2. The EPP impact-resistant packaging board according to claim 1, characterized in that, The nucleating agent is talc or calcium carbonate; the surfactant is any one of calcium stearate, zinc stearate, or ethylene bis-stearamide.

3. The EPP impact-resistant packaging board according to claim 1, characterized in that, The preparation method of the rhein-modified Eucommia gum includes the following steps: S1: Weigh out Eucommia ulmoides gum powder, add it to a three-necked round-bottom flask, add deionized water, heat to 50-55℃, stir for 1-2 hours, add glacial acetic acid and hydrogen peroxide dropwise while stirring, after reacting for 5-6 hours, add sodium carbonate, stir until no bubbles are generated, filter, wash with deionized water until neutral, and vacuum dry to obtain epoxidized Eucommia ulmoides gum; S2: Place epoxidized Eucommia ulmoides gum in toluene, add rhein and catalyst, purge with nitrogen, heat to 90-100℃ and react for 8-10 hours. After cooling to room temperature, place the mixture in ethanol to precipitate, filter and wash with ethanol 3-5 times, vacuum dry and collect the product to obtain rhein-modified Eucommia ulmoides gum.

4. The EPP impact-resistant packaging board according to claim 3, characterized in that, In step S1, the hydrogen peroxide has a mass fraction of 30-36%.

5. The EPP impact-resistant packaging board according to claim 3, characterized in that, In step S2, the catalyst is any one of tetrabutylammonium bromide, tetrabutylammonium chloride, and tetrabutylammonium hydroxide.

6. The EPP impact-resistant packaging board according to claim 1, characterized in that, The preparation method of the phosphorylated maifanite fiber includes the following steps: SS1: Place maifan stone fiber in toluene, ultrasonically disperse for 10-15 min, introduce nitrogen gas, add allyl isocyanate and dibutyltin dilaurate, reflux for 6-8 h, cool, filter, wash and vacuum dry to obtain allyl maifan stone fiber. SS2: Allyl maifanite fiber is placed in N,N-dimethylformamide and ultrasonically dispersed for 15-20 min. Nitrogen gas is introduced, vinylphosphonic acid and initiator are added, the temperature is raised to 75-80℃, and the reaction is stirred for 8-10 h. After cooling, filtration, washing and vacuum drying, phosphorylated maifanite fiber is obtained.

7. The EPP impact-resistant packaging board according to claim 6, characterized in that, In step SS1, the length of the maifanite fiber is 50-150 μm and the diameter is 5-15 μm.

8. The EPP impact-resistant packaging board according to claim 6, characterized in that, In step SS2, the initiator is either azobisisobutyronitrile or azobisisoheptanenitrile.

9. A method for preparing an EPP impact-resistant packaging board as described in claim 1, characterized in that, Includes the following steps: Step 1: Place polypropylene resin, rhein-modified eucommia gum, phosphorylated maifan stone fiber, maleic anhydride-grafted EPDM rubber, nucleating agent, and surfactant in a high-speed mixer and mix evenly. Transfer the mixture to a twin-screw extruder, set the extrusion temperature to 180-200℃ and the screw speed to 200-300rpm, melt extrude, cool, and granulate to obtain premixed granules. Step 2: Transfer the premixed granules to a high-pressure autoclave, seal it, introduce CO2, heat to 155-165℃, pressurize to 10-12MPa, and after 2-2.5h, open the pressure relief valve and control the pressure relief rate to 1-1.2MPa / s to obtain EPP foamed beads. Step 3: Fill the mold with EPP foam beads evenly, introduce steam at 0.4-0.5MPa, heat to 130-140℃, keep warm for 30-40s, wait for the surface of the beads to soften and fuse together, cool to room temperature and demold to obtain EPP impact-resistant packaging board.

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