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CN-122011544-A - Highly waterproof composite packaging bag and preparation method thereof

CN122011544ACN 122011544 ACN122011544 ACN 122011544ACN-122011544-A

Abstract

The invention discloses a highly waterproof composite packaging bag and a preparation method thereof in the field of packaging materials, the raw materials comprise low-density polyethylene, high-density polyethylene, perfluoroalkyl-polyurethane-polysilsesquioxane ternary hybrid, dynamic covalent bond modified polyether-acrylate block polymer, antioxidant and ultraviolet light absorber. The ternary hybrid is prepared by the reaction of hexafluoropropylene, isophorone diisocyanate and octaamino cage-shaped siloxane derivatives, contains perfluoroalkyl and a nano cage hydrophobic skeleton, and the dynamic covalent bond modified polymer is synthesized by the crosslinking reaction of polyethylene glycol, glycidyl methacrylate and boric acid modified coupling agent and contains a dynamic and permanent crosslinking structure. The packaging bag is capable of remarkably reducing the moisture permeability through the synergistic effect of the low-surface-energy hydrophobic component and the cross-linked network, has high surface hydrophobicity and high water resistance stability, and is suitable for severe packaging scenes of foods, electronic devices and the like.

Inventors

  • CHEN JIAN
  • QU YANFEI

Assignees

  • 东营正宜包装股份有限公司

Dates

Publication Date
20260512
Application Date
20251231

Claims (10)

  1. 1. The high waterproof composite packaging bag is characterized by comprising the following raw materials in parts by weight: 750-900 parts by weight of low-density polyethylene; 50-150 parts by weight of high-density polyethylene; 20-60 parts by weight of perfluoroalkyl-polyurethane-polysilsesquioxane ternary hybrid; 10-40 parts by weight of dynamic covalent bond modified polyether-acrylate block polymer; 1-3 parts of antioxidant; 0.5-1 parts by weight of an ultraviolet absorber; The preparation method of the perfluoroalkyl-polyurethane-polysilsesquioxane ternary hybrid comprises the steps of A1, mixing hexafluoropropylene with tetrahydrofuran, adding 1, 4-bis (trifluoromethyl) phenyl lithium under the protection of nitrogen, reacting at a temperature of minus 78 ℃ to generate a perfluoroalkyl lithium intermediate, then adding isophorone diisocyanate, heating to a temperature of 25-30 ℃ to react to form perfluoroalkyl polyurethane prepolymer containing isocyanate groups, simultaneously reacting octaamino POSS with hydroxyethyl acrylate in N, N-dimethylformamide solvent to obtain amino-terminated POSS-HEA derivatives, and finally, mixing the perfluoroalkyl polyurethane prepolymer, the POSS-HEA derivatives with dibutyltin dilaurate, reacting at a temperature of 60-80 ℃, precipitating with acetone, washing and drying in vacuum.
  2. 2. The high waterproof composite packaging bag according to claim 1, wherein in the step A1, the volume ratio of hexafluoropropylene to tetrahydrofuran is 1:2, the reaction time is 3-5h at-78 ℃, the reaction time is 2-4h after the temperature is raised to 25-30 ℃, the molar ratio of octaamino POSS to hydroxyethyl acrylate is 1:2, and the reaction time is 1-2h in an N, N-dimethylformamide solvent.
  3. 3. The highly water-resistant composite packing bag according to claim 1, wherein in the step A2, the reaction time is 6 to 10 hours at 60 to 80 ℃.
  4. 4. The high waterproof composite packaging bag according to claim 1 is characterized in that the preparation method of the dynamic covalent bond modified polyether-acrylate block polymer comprises the steps of adding polyethylene glycol and glycidyl methacrylate into a toluene solvent, adding p-toluenesulfonic acid under the protection of nitrogen, heating to 110-130 ℃ to react to generate epoxy group-terminated polyether-acrylate prepolymer, simultaneously reacting boric acid and 3-aminopropyl triethoxysilane in an ethanol solvent to obtain boric acid modified silane coupling agent, and mixing the epoxy group-terminated polyether-acrylate prepolymer, the boric acid modified silane coupling agent and a photoinitiator, reacting at 50-70 ℃ and distilling under reduced pressure.
  5. 5. The high waterproof composite packaging bag according to claim 4, wherein in the step B1, the molar ratio of polyethylene glycol to glycidyl methacrylate is 1:1, the reaction time is 4-6 hours after the temperature is raised to 110-130 ℃, the molar ratio of boric acid to 3-aminopropyl triethoxysilane is 1:2, and the reaction time is 2-3 hours in an ethanol solvent.
  6. 6. The highly water-resistant composite packing bag according to claim 4, wherein the reaction time at 50 to 70 ℃ in the step B2 is 3 to 5 hours.
  7. 7. A method of making a highly waterproof composite package according to any one of claims 1 to 6, comprising the steps of: S1, adding low-density polyethylene, high-density polyethylene, perfluoroalkyl-polyurethane-polysilsesquioxane ternary hybrid, dynamic covalent bond modified polyether-acrylate block polymer, an antioxidant and an ultraviolet light absorbent into a high-speed mixer, and stirring at 50-60 ℃ until the mixture is uniformly dispersed; s2, adding the mixture into a single screw extruder, extruding the mixture into a film through a T-shaped die after melting and plasticizing, shaping by a cooling roller, drawing, carrying out corona treatment, and then rolling; And S3, finally, placing the rolled film into an ultraviolet curing machine for irradiation.
  8. 8. The method according to claim 7, wherein in the step S1, the stirring time is 10 to 15 minutes at 50 to 60 ℃.
  9. 9. The process according to claim 7, wherein in step S2, the single screw extruder barrel temperature is 180-210℃and the screw speed is 80-100rpm.
  10. 10. The method according to claim 7, wherein in step S3, the ultraviolet light wavelength of the ultraviolet light curing machine is 365 nm, the intensity is 150-200 mW/cm2, and the irradiation time is 8-12min.

Description

Highly waterproof composite packaging bag and preparation method thereof Technical Field The invention relates to the technical field of packaging materials, in particular to a high waterproof composite packaging bag and a preparation method thereof. Background In the field of packaging materials, packaging bags with single-layer structures are widely applied to packaging links of products such as foods, medicines, electronic devices and the like for a long time by virtue of the advantages of simple production process and low cost. Such packages are generally made of polymeric materials such as polyethylene, polypropylene, etc., the basic structure of which is composed of linear or branched polymer chains. However, these materials naturally have micro-to nano-scale pore structures between the molecular chains, and some of the polymer molecular chains contain polar groups capable of interacting with water molecules, which are affected by the molecular chain arrangement characteristics of the polymer. When the packaging bag is in a high humidity environment or is in direct contact with liquid water, the moisture can migrate in the pores through diffusion or permeate along pore channels by capillary effect, even form hydrogen bonds with polar groups and the like to interact, and then penetrate the packaging material into the interior. This phenomenon directly leads to the risk of moisture, mildew, corrosion, etc. in the packaged product, the food may grow microorganisms due to moisture intrusion, the medicine may have reduced efficacy or deteriorated due to moisture absorption, the electronic components may cause short circuit or circuit corrosion due to moisture condensation, and the precision instruments may affect the measurement accuracy or mechanical properties due to humidity changes. Therefore, the blocking capability of the single-layer packaging bag to moisture is improved, and the single-layer packaging bag becomes a key problem of guaranteeing the quality and the function stability of products in the packaging bag. In order to solve the defect of insufficient waterproof performance of the traditional single-layer packaging bag, the prior art scheme is mainly developed around two ideas of surface treatment and filler addition. The surface treatment technology generally coats a layer of coating with hydrophobic property on the surface of a polymer matrix, and the water drops are difficult to spread on the surface of the material and form rolling separation effect by the characteristics of low surface energy and weak affinity with water molecules of the coating material, so that the water penetration is reduced. However, the coating and the matrix are combined mainly by means of physical adhesion, and the coating is easily affected by factors such as friction, aging, ultraviolet irradiation or temperature change in the long-term use process, so that the coating is locally dropped, cracked or attenuated in performance, and the overall waterproof effect is further destroyed. Another technical scheme is to add a hydrophobic filler in the polymer processing process, and form a physical barrier layer in the polymer matrix by utilizing the hydrophobic surface characteristics and the steric hindrance effect of the filler, so as to reduce the permeation path of moisture. However, the method has the limitations that the nanoscale filler is extremely easy to agglomerate in the polymer matrix due to the high surface energy of the filler, uniform dispersion cannot be realized, the agglomerated filler cannot effectively block a moisture permeation channel, but can form a defect area in the matrix to become a break of preferential moisture permeation, and in addition, part of the filler can have migration and precipitation risks, so that the sanitation safety and long-term use performance of the packaging material are affected. The problems cause that the traditional improvement method is difficult to meet the application scene requirements of foods, medicines and the like with strict requirements on waterproof performance, and the development of a novel single-layer packaging material capable of realizing the essential improvement of the waterproof performance from the molecular level of the material is urgently needed. Aiming at the technical bottleneck, the invention provides an innovative solution that a waterproof mechanism with a low surface energy hydrophobic structure and a cross-linked network in a single-layer polyethylene matrix are constructed by synthesizing two modified compounds with brand new structures. Specifically, the hybridized compound containing perfluoroalkyl and cage polysilsesquioxane is designed, so that the hydrophilicity of the whole material is reduced by utilizing the low surface energy characteristic of the perfluoroalkyl, water drops are more likely to form rolling separation effect on the surface, and micropores among polymer molecular chains are filled by virtue of the nanoscale ri