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CN-121975275-A - PET antifog antibacterial sheet and production process thereof

CN121975275ACN 121975275 ACN121975275 ACN 121975275ACN-121975275-A

Abstract

The invention belongs to the field of PET sheets, and discloses a PET antifogging antibacterial sheet and a production process thereof, wherein the PET antifogging antibacterial sheet is prepared from, by weight, 72-85 parts of PET resin, 3-8 parts of antibacterial master batches, 2-5 parts of polyglycerol fatty acid ester-chitosan composite antifogging auxiliary agent, 1-4 parts of toughening agent, 0.5-2.0 parts of antistatic agent, 1-3 parts of compatilizer, 0.3-1.0 parts of lubricant, 0.2-0.8 parts of release agent, 0.2-0.8 parts of antioxidant and 0.5-1.5 parts of trehalose modified nano silicon dioxide, so that the problems that the conventional PET agricultural product package only needs perforation, ventilation and water permeation, water condensation and fogging are not solved, and agricultural product spoilage are accelerated are solved, and the problems that the antifogging effect of the PET sheet produced by the conventional coating process is poor, an antifogging coating is easy to fall off, and food safety is influenced are solved.

Inventors

  • LI YUYU
  • YAN KAN
  • LI MINGDA

Assignees

  • 江阴市德惠热收缩包装材料有限公司

Dates

Publication Date
20260505
Application Date
20260112

Claims (10)

  1. 1. The PET antifogging antibacterial sheet is characterized by being prepared from the following raw materials, by weight, 72-85 parts of PET resin, 3-8 parts of antibacterial master batches, 2-5 parts of polyglycerol fatty acid ester-chitosan composite antifogging auxiliary agent, 1-4 parts of toughening agent, 0.5-2.0 parts of antistatic agent, 1-3 parts of compatilizer, 0.3-1.0 part of lubricant, 0.2-0.8 part of release agent, 0.2-0.8 part of antioxidant and 0.5-1.5 parts of trehalose modified nano silicon dioxide; The antibacterial master batch is a PET carrier antibacterial master batch, and is prepared by melting, blending and granulating silver-loaded zeolite, nano zinc oxide, graphene quantum dots and PET slices in a weight ratio of 3:2:3:1; the antistatic agent is sulfonated polyether ether ketone (SPEEK); the compatilizer is glycidyl methacrylate grafted PET (GMA-g-PET); The lubricant is polyethylene glycol monostearate (PEG 4000-monostearate); the release agent is polysiloxane grafted polymethyl methacrylate (PDMS-g-PMMA); The antioxidant is a compound of antioxidant 1010 and antioxidant 168, and the weight ratio is 1:1-2.
  2. 2. The multifunctional PET antifogging and antibacterial sheet according to claim 1, wherein the intrinsic viscosity of the PET resin is 0.70-0.78dL/g, the melting point is 253-258 ℃, and the water content is less than or equal to 0.05%.
  3. 3. The multifunctional PET antifogging and antibacterial sheet according to claim 1, wherein in the antibacterial master batch, the particle size of silver-loaded zeolite is 1-5 μm, the particle size of nano zinc oxide is 20-50nm, the particle size of graphene quantum dots is 5-15nm, and the intrinsic viscosity of the PET carrier is consistent with that of main PET resin.
  4. 4. The multifunctional PET antifogging and antibacterial sheet according to claim 1, wherein in the polyglycerin fatty acid ester-chitosan composite antifogging auxiliary agent, the hydroxyl value of the polyglycerin fatty acid ester is 150-200mgKOH/g, and the molecular weight of chitosan is 50000-100000Da.
  5. 5. The multifunctional PET antifogging antibacterial sheet according to claim 1, wherein the modification rate of the trehalose modified nano silicon dioxide is 8-12%, and the weight portion of the trehalose modified nano silicon dioxide in the raw materials is 0.8-1.2.
  6. 6. The multifunctional PET antifogging and antibacterial sheet according to claim 1, wherein the sulfonation degree of the antistatic agent is 45-55mol%, and the weight part of the antistatic agent in the raw material is 1.0-1.5 parts.
  7. 7. The multifunctional PET antifogging and antibacterial sheet according to claim 1, wherein the preparation method of the polyglycerol fatty acid ester-chitosan composite antifogging auxiliary agent is characterized in that the polyglycerol fatty acid ester and chitosan with the deacetylation degree of more than or equal to 90% are weighed according to the weight ratio of 3:1, the chitosan is dispersed in 5% acetic acid aqueous solution, the polyglycerol fatty acid ester is added after stirring until the chitosan is completely dissolved, stirring is carried out for 2-3 hours at a constant temperature of 60-70 ℃, and the powdery composite antifogging auxiliary agent is obtained through spray drying (the air inlet temperature is 160-180 ℃ and the air outlet temperature is 80-90 ℃).
  8. 8. The multifunctional PET antifogging antibacterial sheet according to claim 1, wherein the preparation method of the trehalose modified nano silicon dioxide is characterized in that nano silicon dioxide with the particle size of 10-30nm is dispersed in absolute ethyl alcohol, trehalose with the mass of 10-15% of the nano silicon dioxide is added, stirring is carried out for 1.5-2h at 50-60 ℃, then a sol-gel method is adopted for reacting for 3-4h under the condition of pH=4-5, and the modified product is obtained through centrifugation, washing and vacuum drying for 6h at 80 ℃, wherein the toughening agent is polycaprolactone grafted maleic anhydride (PCL-g-MAH), and the grafting rate is 1.5-2.2%.
  9. 9. A process for producing a multifunctional PET antifogging antibacterial sheet according to any one of claims 1 to 8, characterized by comprising the steps of: s1, raw material pretreatment, namely vacuum drying PET resin for 4-6 hours at 120-140 ℃, drying antibacterial master batch, toughening agent, compatilizer and trehalose modified nano silicon dioxide for 3-4 hours at 100-110 ℃, and drying polyglycerol fatty acid ester-chitosan composite antifogging auxiliary agent, antistatic agent, lubricant, release agent and antioxidant for 2-3 hours at 80-90 ℃ to ensure that the water content of all raw materials is less than or equal to 0.03%; S2, mixing ingredients, namely weighing all the pretreated raw materials according to parts by weight, firstly putting PET resin, antibacterial master batch, toughening agent, compatilizer and trehalose modified nano silicon dioxide into a high-speed mixer, mixing for 10-15min at 80-95 ℃ and the rotating speed of 300-400r/min, and then adding polyglycerol fatty acid ester-chitosan composite antifogging auxiliary agent, antistatic agent, lubricant, release agent and antioxidant, and continuously mixing for 5-10min at the same temperature to obtain a uniform mixed material; S3, melt extrusion, namely feeding the mixed material into a double-screw extruder, setting the length-diameter ratio of the double-screw extruder to be 40:1, setting the temperature of each section to be 245-255 ℃ and 255-265 ℃ and 250-260 ℃ and obtaining a homogenized melt by melt blending extrusion, wherein the screw rotating speed is 220-280r/min and the vacuum degree is 0.08-0.09 MPa; S4, calendaring and molding, namely feeding the melt into a sheet die, wherein the die temperature is 250-260 ℃, calendaring by a three-roller calendar, the three-roller temperature is 85-95 ℃ respectively (a first roller), 65-75 ℃ respectively (a second roller) and 55-65 ℃ respectively (a third roller), the calendaring speed is 1.2-2.5m/min, and the roller gap is 0.2-2.0mm; S5, surface activation, namely feeding the formed sheet into a low-temperature plasma processor, taking argon and oxygen (volume ratio is 3:1) as working gases, and activating surface hydroxyl groups, wherein the power is 90-130W, the processing time is 40-70s, and the processing distance is 6-10 mm; s6, post-treatment, namely naturally cooling the sheet to room temperature, and carrying out traction by a tractor, trimming by a trimming machine and rolling by a rolling machine to obtain the multifunctional PET antifogging antibacterial sheet.
  10. 10. The production process according to claim 7, wherein in step S2, the mixing time of the high-speed mixer is 15-25min in total, and the temperature of the mixed material is not more than 100 ℃, so that the decomposition of the polyglycerin fatty acid ester-chitosan composite anti-fog auxiliary agent and the antistatic agent is avoided.

Description

PET antifog antibacterial sheet and production process thereof Technical Field The invention relates to the technical field of PET (polyethylene terephthalate) sheets, in particular to a PET anti-fog antibacterial sheet and a production process thereof. Background The utility model provides a fresh-keeping of agricultural products, which relates to the technical and principle of food preservation, and has the core purposes of prolonging the shelf life of the agricultural products, reducing the food waste and ensuring the quality and safety of the agricultural products from the production place to the consumption process. In the agricultural product circulation link, the performance of the packaging material directly influences the fresh-keeping effect, namely, moisture can be continuously volatilized in the storage and transportation processes of vegetables, fruits and foods, if the moisture is condensed on the inner surface of the packaging material, water drops (namely, a 'fogging' phenomenon) can be formed, so that the observation of consumers on products is influenced, high-temperature and high-humidity microenvironments can be created, the propagation of microorganisms such as bacteria and mold is accelerated, the vegetables, fruits and foods are quickly spoiled, and serious resource waste and economic loss are caused. At present, a PET plastic uptake packing box is widely adopted in the market as a packing carrier of agricultural products such as fruits and vegetables, and in order to realize basic fresh-keeping, a plurality of ventilation holes are formed in a box body, and the accumulation of internal humidity is relieved in a permeable and breathable mode, so that the spoilage process of the fruits and vegetables is delayed. However, the traditional PET packaging has obvious technical defects: The anti-fog effect is lost, namely, the problem of moisture condensation and fog can not be solved only by punching, water drops can still be formed on the inner surface of the box, and conditions are provided for microorganism breeding; The traditional PET material has no antibacterial activity, and the ventilation holes can become channels for invasion of microorganisms instead, so that the invasion of microorganisms on agricultural products can not be inhibited; The metabolic process can not be regulated and controlled, namely the oxidation reaction and the respiratory metabolism rate of vegetables and fruits can not be controlled, and the physiological activities of agricultural products can accelerate the nutrition loss and the quality reduction; The functions are single, the durability is poor, and even if a single antifogging agent or antibacterial agent is added to part of the products, the problems of poor compatibility of the auxiliary agent and PET base materials and easy migration and loss exist, so that the fresh-keeping effect is invalid in a short period. With the improvement of agricultural product productivity and the increasing of the requirements of consumers on food freshness and safety, the preservation efficiency of the traditional PET plastic-sucking packaging box cannot meet the actual requirements. In the prior art, no scheme has been provided for simultaneously solving four core pain points of antifogging, antibiosis, oxidation metabolism inhibition and function durability, and especially technical report of cooperatively applying a composite antifogging auxiliary agent and a modified nano material to agricultural product preservation PET packaging is lacking, and a multi-auxiliary agent cooperative formula and a process system aiming at agricultural product preservation scenes are not formed. In order to fill the technical blank, the invention provides the multifunctional PET sheet with the functions of anti-fog, antibacterial, antistatic and toughening by innovatively designing the composite anti-fog and antibacterial system and optimizing the raw material proportion and the production process, can be directly used for fresh-keeping packaging of agricultural products, effectively prolongs the shelf life of the agricultural products, solves the defects of the prior art, and solves the problems that the PET sheet produced by the traditional coating process has poor anti-fog effect, an anti-fog coating is easy to fall off, the food safety is influenced and the like. Disclosure of Invention The invention aims to provide a PET antifogging antibacterial sheet and a production process thereof, which are used for solving the problems that the conventional PET agricultural product package is only perforated, breathable and permeable, the problem of moisture condensation and fogging cannot be solved, the agricultural product spoilage is accelerated, the conventional PET package has no antibacterial function, can not inhibit the invasion of microorganisms, ventilation holes are easy to become microorganism invasion channels, single functional auxiliary agents (such as a single antifogging ag