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CN-122011585-A - High-barrier composite material for PP/PE-based tableware and preparation method thereof

CN122011585ACN 122011585 ACN122011585 ACN 122011585ACN-122011585-A

Abstract

The invention provides a high-barrier composite material for PP/PE-based tableware and a preparation method thereof, which belong to the technical field of food contact materials, and the composite material comprises a PP/PE matrix, PDA coated chlorine-receiving fibers, PP-g-MAH phosphorus/silicon crosslinked materials, nano lamellar fillers and food-grade auxiliary agents, and is prepared by a three-step method: firstly preparing PDA coated chlorine-grafted fibers to construct a hydrophobic foundation, then preparing PP-g-MAH phosphorus/silicon cross-linked matter to strengthen interface combination, and finally preparing the tableware through melt blending and injection molding. The invention makes the composite material have excellent water/oil permeation resistance and mechanical property through the synergistic effect of 'PDA chlorine-receiving hydrophobic, phosphorus/silicon crosslinking enhancement and nanometer lamellar barrier', and the material is suitable for the existing injection molding process, accords with the food contact safety standard, can be widely applied to the preparation of PP/PE tableware such as dinner plates, dinner bowls and the like, and solves the technical problem of poor barrier property of the traditional PP/PE tableware.

Inventors

  • ZHANG GUANGHUI
  • GAO JIE
  • Xi Qiqing
  • WU ZHAORUI
  • ZHANG TENGFEI
  • ZHANG HONGMING

Assignees

  • 河南信太新材科技有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (10)

  1. 1. The high-barrier composite material for the PP/PE-based tableware is characterized by comprising the following components in parts by weight: 40-60 parts of PP/PE matrix; 5-15 parts of PDA coated chlorine-containing fiber; 20-35 parts of PP-g-MAH phosphorus/silicon cross-linked matter; 3-8 parts of nano lamellar filler; 1-3 parts of a heat stabilizer; 0.5-1.5 parts of lubricant.
  2. 2. The PP/PE based high barrier composite of claim 1, wherein the PP/PE matrix is one or more of food grade homo-, co-or high density polyethylene, wherein the polypropylene has a melt index of 1-6g/10min (230 ℃,2.16 kg), the polyethylene has a melt index of 1-3g/10min (190 ℃,2.16 kg), the heat stabilizer is at least one of hindered phenols and phosphites, and the lubricant is at least one of erucamide, stearate, and silicone masterbatch.
  3. 3. The high barrier composite for PP/PE-based tableware of claim 1, wherein the method for preparing the PDA-coated chlorine-receiving fiber comprises the steps of: Dispersing plant fibers in Tris-HCl buffer solution with pH value of 8.0-8.5, adding dopamine monomer to make the concentration of dopamine be 1-5g/L, stirring at room temperature for 12-24h to form PDA coated fibers, immersing the PDA coated fibers in chlorosilane-containing ethanol solution, reacting for 4-6h at 50-60 ℃, taking solid phase for washing, and drying at 60-80 ℃ for 4-6h to obtain the PDA coated chlorine-receiving fibers.
  4. 4. The PP/PE based high barrier composite material for tableware of claim 3, wherein the plant fiber comprises bamboo fiber or wood fiber having a diameter of 50-200 μm, the chlorosilane is methyltrichlorosilane or dimethyldichlorosilane, the volume fraction of the chlorosilane in the chlorosilane ethanol solution is 3-6%, and the chlorine content in the PDA-coated chlorine-receiving fiber is 1.5-3wt%.
  5. 5. The high barrier composite for PP/PE-based tableware of claim 1, wherein the method for preparing PP-g-MAH phosphorus/silicon crosslinked material comprises: Adding PP-g-MAH, a phosphorus-containing siloxane compound and a catalyst into a high-speed mixer, stirring uniformly, transferring into a double-screw extruder, carrying out melt reaction for 5-10min at 180-200 ℃, extruding and granulating to obtain the PP-g-MAH phosphorus/silicon cross-linked product.
  6. 6. The PP/PE based high barrier composite of claim 5, wherein the mass ratio of PP-g-MAH to the phosphorus-containing siloxane compound is (8-10): 1, and the catalyst is added in an amount of 0.1-0.3% of the mass of PP-g-MAH.
  7. 7. The high-barrier composite material for PP/PE-based tableware according to claim 6, wherein the grafting ratio of maleic anhydride of PP-g-MAH is 1.0-1.5%, the phosphorus-containing siloxane compound is formed by compounding gamma-aminopropyl triethoxysilane and monoammonium phosphate according to a mass ratio of (2-6): 1, and the catalyst is dibutyl tin dilaurate.
  8. 8. The high-barrier composite material for PP/PE-based tableware of claim 1, wherein the nano lamellar filler is montmorillonite, hydrotalcite or graphene oxide nano sheets, the sheet diameter is 100-500nm, the thickness is 1-5nm, and the nano lamellar filler is used after being subjected to surface modification by gamma-aminopropyl triethoxysilane.
  9. 9. A method for preparing a high-barrier composite material for PP/PE-based tableware, which adopts the high-barrier composite material for PP/PE-based tableware as defined in any one of claims 1 to 8, and is characterized by comprising: S1, weighing a PP/PE matrix, a PDA coated chlorine-containing fiber, a PP-g-MAH phosphorus/silicon cross-linked matter, a nano lamellar filler, a heat stabilizer and a lubricant according to parts by weight, adding a high-speed mixer, stirring for 0.2-0.4h to be uniform at 1200-1500rpm, then transferring into a double-screw extruder for extrusion granulation, wherein the extrusion temperature is 160-220 ℃ and the screw rotation speed is 300-500rpm; S2, adding the composite particles prepared in the step S1 into an injection molding machine, setting the temperature of a charging barrel to be 180-220 ℃, setting the temperature of a mold to be 60-80 ℃, injecting 1500-1800bar, maintaining 1200-1600bar, and cooling for 1-3S, so as to obtain finished products of the tableware through injection molding.
  10. 10. The method for preparing the high-barrier composite material for the PP/PE tableware of claim 9, wherein the temperature of each section of the twin-screw extruder in the step S1 is sequentially 160-170 ℃, 180-190 ℃ in one section, 190-200 ℃ in three sections, 200-210 ℃ in four sections and 210-220 ℃ in a nose.

Description

High-barrier composite material for PP/PE-based tableware and preparation method thereof Technical Field The invention relates to the technical field of food contact materials, in particular to a high-barrier composite material for PP/PE-based tableware and a preparation method thereof. Background Polypropylene (PP) and Polyethylene (PE) are widely used in the field of tableware manufacturing due to their excellent processability, low cost and good chemical stability. However, the conventional PP/PE tableware has obvious technical defects of poor barrier property and insufficient barrier capability to water vapor, oxygen and grease, so that the contained food is easy to deteriorate and taint smell, the quality guarantee period of the food is shortened, and in addition, the conventional PP/PE tableware is easy to deform, the mechanical property is reduced and the like under the conditions of high-temperature use or microwave heating. In order to solve the problems, the prior art adopts a mode of adding inorganic filler or surface coating to modify PP/PE, wherein the former adopts a mode of constructing a layered barrier structure by oxidized graphene/layered double hydroxide, and combines heat resistance and mechanical enhancement, but nano filler has poor dispersibility in a PP/PE matrix and is easy to agglomerate, so that the barrier performance is unstable, and the latter adopts fluorine-containing polymer or organic silicon resin to construct a hydrophobic coating on the surface of a substrate, so that the improvement of hydrophobicity and oleophobicity can be realized, but the interface bonding force between the coating and the PP/PE matrix is weak, the mechanical property of the material is insufficient, and the requirements of forming and using high-quality tableware can not be met. Meanwhile, with the increasing strictness of the safety standards of food contact materials (such as GB 4806.7-2023), higher requirements are put on the control of the safety and migration of components of materials for tableware. Fluorine-containing compounds, which are commonly used in the prior art, are partially perfluoro and polyfluoroalkyl substances (PFAS) and have been limited in use by European Union, the United states and other areas. Therefore, developing a PP/PE-based composite material which has a high barrier function and meets the food contact safety standard becomes an urgent need of the current tableware industry. Disclosure of Invention The invention aims to provide a high-barrier composite material for PP/PE-based tableware and a preparation method thereof, which are used for solving the problems in the prior art. In order to achieve the above purpose, the present invention provides the following technical solutions: the high-barrier composite material for the PP/PE-based tableware comprises the following components in parts by weight: 40-60 parts of PP/PE matrix; 5-15 parts of PDA coated chlorine-containing fiber; 20-35 parts of PP-g-MAH phosphorus/silicon cross-linked matter; 3-8 parts of nano lamellar filler; 1-3 parts of a heat stabilizer; 0.5-1.5 parts of lubricant. Further, the PP/PE matrix is one or more of food-grade homo-polypropylene, co-polypropylene or high-density polyethylene, wherein the melt index of the polypropylene is 1-6g/10min (230 ℃ and 2.16 kg), the melt index of the polyethylene is 1-3g/10min (190 ℃ and 2.16 kg), good injection molding performance of the material is ensured, meanwhile, the requirement of the tableware on mechanical strength is met, the heat stabilizer is at least one of hindered phenols and phosphites, the thermal oxidative degradation of the PP/PE matrix in the processing process can be effectively inhibited, and the lubricant is at least one of erucamide, stearate and silicone master batch, so that the friction resistance in the processing process is reduced, and the surface finish of the product is improved. The preparation method of the PDA coated chlorine-containing fiber comprises the steps of dispersing plant fibers in Tris-HCl buffer solution with pH value of 8.0-8.5, adding dopamine monomers to enable the concentration of dopamine to be 1-5g/L, stirring at room temperature for 12-24h to enable dopamine to self-polymerize on the surfaces of the fibers to form a PDA coated layer, immersing the fibers coated by the PDA into chlorosilane ethanol solution with the volume fraction of 3-6%, reacting for 4-6h at 50-60 ℃ to enable the chlorosilane to generate covalent grafting with the PDA layer, taking a solid phase after the reaction is finished, sequentially washing for 3-5 times by ethanol and deionized water, drying for 4-6h at 60-80 ℃ to obtain the PDA coated chlorine-containing fiber, wherein the chlorine content of the PDA coated chlorine-containing fiber is 1.5-3wt%. Further, the plant fiber comprises bamboo fiber or wood fiber, the diameter of the plant fiber is 50-200 mu m, the plant fiber has the advantages of wide sources and degradability, the chloro