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CN-122011249-A - Preparation method of oil-resistant swelling polyethylene film

CN122011249ACN 122011249 ACN122011249 ACN 122011249ACN-122011249-A

Abstract

The invention provides a preparation method of an oil-resistant swelling polyethylene film, and belongs to the technical field of plastic films. According to the invention, the functional monomer is introduced into a polyethylene main chain in a covalent manner by preparing the functional monomer containing the terminal olefin with the ureido-pyrimidinone structure and copolymerizing the functional monomer with ethylene, and then carrying out melt extrusion film blowing, and a reversible polymer network based on multiple hydrogen bonding is constructed in an amorphous region, so that the oil-resistant swelling performance of the polyethylene film is improved, and the process feasibility and the film processing suitability are achieved.

Inventors

  • LIU ZHAOBIN
  • MA YULIN
  • CHEN YUNFANG

Assignees

  • 江苏新鲁新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260302

Claims (10)

  1. 1. A method for preparing an oil-resistant swelling polyethylene film, which is characterized by comprising the following steps: s1, in a first solvent and an acid binding agent, carrying out phosgenation reaction on 10-undecylenic amine and triphosgene to obtain 10-undecylenic isocyanate; s2, carrying out nucleophilic addition reaction on the 10-undecenyl isocyanate and 2-amino-4-hydroxy-6-methyl pyrimidine in a second solvent to obtain an olefin-terminated functional monomer; S3, in the presence of a catalyst and a cocatalyst, carrying out copolymerization reaction on the olefin-terminated functional monomer and ethylene in a third solvent to obtain modified polyethylene resin; and S4, melting and extruding the modified polyethylene resin, and performing film blowing molding to obtain the oil-resistant swelling polyethylene film.
  2. 2. The method according to claim 1, wherein in the step S1, the acid binding agent is triethylamine, and the first solvent is selected from dichloromethane or toluene; And/or the feeding mole ratio of the 10-undecylenic amine, the triphosgene and the acid binding agent is 1 (0.3-0.4): 1.8-2.2.
  3. 3. The method according to claim 1, wherein the phosgenation reaction conditions in the step S1 include dropping 10-undecylamine and an acid-binding agent into a first solvent containing triphosgene at-5 to 5 ℃, and heating to 40 to 80 ℃ after the completion of the dropping for reflux reaction for 3 to 5 hours.
  4. 4. The method according to claim 1, wherein in the step S2, the molar ratio of the 10-undecenyl isocyanate to the 2-amino-4-hydroxy-6-methylpyrimidine is (1.05-1.15): 1; and/or the second solvent is selected from pyridine or dimethyl sulfoxide.
  5. 5. The method according to claim 1, wherein in step S2, the conditions for the nucleophilic addition reaction include a reaction temperature of 90 to 110℃and a reaction time of 12 to 16 hours.
  6. 6. The method according to claim 1, wherein in step S2, the reaction product of the nucleophilic addition reaction is purified by recrystallizing the reaction product with a mixed solvent of chloroform and methanol.
  7. 7. The process according to claim 1, wherein in step S3, the catalyst is a sterically hindered α -diimine nickel catalyst comprising [ N, N' -bis (8- (phenylamino) -1-naphthyl) acenaphthylene-1, 2-diimine ] nickel (II) dibromide, the promoter being diethylaluminum chloride; and/or the third solvent is selected from toluene or chlorobenzene.
  8. 8. The process of claim 1, wherein in step S3, the molar ratio of the terminal olefin functional monomer to ethylene is (1-3) 100, and the molar ratio of the terminal olefin functional monomer, catalyst and cocatalyst is (1000-2000) 1 (200-500).
  9. 9. The method according to claim 1, wherein the conditions for the copolymerization reaction in step S3 include a reaction temperature of 20 to 50℃and a reaction time of 1 to 3 hours.
  10. 10. The method according to claim 1, wherein in step S4, the processing temperature of the blown film is 160-190 ℃.

Description

Preparation method of oil-resistant swelling polyethylene film Technical Field The invention belongs to the technical field of plastic films, and particularly relates to a preparation method of an oil-resistant swelling polyethylene film. Background Polyethylene (PE) films are widely used in flexible packaging for food, daily chemicals and industrial goods due to their good processability, chemical stability and cost advantages. However, with the increasing demand of flexible packages such as oil-containing foods, lubricating oils and petrochemical products, the problem of performance decay of the conventional PE film is easy to occur in the grease environment. The PE is a nonpolar aliphatic framework, the solubility parameter of the PE is similar to that of hydrocarbon oil products such as vegetable oil, mineral oil and the like, and the oil molecules are easy to diffuse into the PE and cause swelling and plasticization, so that the PE can cause structural instability in severe cases. In the prior art, in order to improve the oil-swelling resistance of a polyethylene film, a multilayer coextrusion/compounding mode is generally adopted to introduce a barrier layer such as EVOH, PA and the like, or means such as ionomer modification, chemical crosslinking and the like are adopted to inhibit oil molecule permeation and material plasticization. However, the scheme has the general defects that the multilayer structure often needs a bonding layer and is accompanied with the problems of narrow processing window and complex process, meanwhile, the multi-material compounding is unfavorable for recycling, the development trend of single-material recyclable packaging is difficult to meet, the ionomer system can strengthen the barrier through ion aggregation, but has higher raw material cost, is sensitive to humidity, is easy to cause performance fluctuation and increases processing stability risk, and chemical crosslinking can reduce swelling, but can obviously weaken the thermoplasticity and the reworkability of the material, so that the blowing film forming and recycling cycle is limited. In addition, there are attempts to introduce a strong polar group or a structure capable of forming physical association into polyethylene to improve oil resistance, but in an ethylene coordination polymerization system, polar monomers tend to cause deactivation of catalyst or decrease in polymerization controllability, and may damage the crystalline structure of polyethylene to cause deterioration of mechanical properties and processability, so that it is difficult to achieve a compromise between oil resistance, film forming processability and recyclability. Therefore, a preparation technical route capable of remarkably improving the anti-swelling capacity of the polyethylene film in an oil environment on the premise of keeping the thermoplastic processing and recycling properties of the polyethylene film is still needed, so that the comprehensive requirements of oil-containing food, oil product packaging and other applications on oil resistance, mechanical properties, processing suitability and recyclability are met. Disclosure of Invention In view of the foregoing, it is an object of the present invention to provide a method for preparing an oil-resistant swelling polyethylene film, which at least partially solves the problems set forth in the background art. The technical scheme adopted by the invention is as follows: The invention provides a preparation method of an oil-resistant swelling polyethylene film, which comprises the following steps: s1, in a first solvent and an acid binding agent, carrying out phosgenation reaction on 10-undecylenic amine and triphosgene to obtain 10-undecylenic isocyanate; s2, carrying out nucleophilic addition reaction on the 10-undecenyl isocyanate and 2-amino-4-hydroxy-6-methyl pyrimidine in a second solvent to obtain an olefin-terminated functional monomer; S3, in the presence of a catalyst and a cocatalyst, carrying out copolymerization reaction on the olefin-terminated functional monomer and ethylene in a third solvent to obtain modified polyethylene resin; and S4, melting and extruding the modified polyethylene resin, and performing film blowing molding to obtain the oil-resistant swelling polyethylene film. In some embodiments of the present invention, in step S1, the acid-binding agent is triethylamine, the first solvent is selected from dichloromethane or toluene; And/or the feeding mole ratio of the 10-undecylenic amine, the triphosgene and the acid binding agent is 1 (0.3-0.4): 1.8-2.2. In some embodiments of the invention, the phosgenation reaction conditions in step S1 include dropwise addition of 10-undecylamine and an acid binding agent to a first solvent comprising triphosgene at a temperature of-5 to 5 ℃ and a reflux reaction at a temperature of 40 to 80 ℃ for 3 to 5 hours after the completion of the dropwise addition. In some embodiments of the invention, in step S2, the molar