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CN-121574404-B - Preparation method of temperature-induced dual-response film, film and application thereof

CN121574404BCN 121574404 BCN121574404 BCN 121574404BCN-121574404-B

Abstract

The invention relates to the technical field of temperature-sensitive color-changing films, in particular to a preparation method of a temperature-sensitive dual-response film, and a film and application thereof. The preparation method comprises the following steps of S1, mixing a color-developing agent, a reversible thermochromic dye, a phase-change regulator and a packaging material, adding water, preparing an emulsion through high-speed shearing, heating to enable the emulsion to self-assemble at high temperature, then sequentially carrying out suction filtration, washing and drying to obtain temperature-sensitive color-changing microcapsules, S2, dispersing the temperature-sensitive color-changing microcapsules in an organic solvent, then adding a surface activation modifier to obtain modified temperature-sensitive color-changing microcapsules, S3, mixing a matrix polymer and an epoxy chain extender, extruding and granulating to obtain a chain-extending matrix polymer, S4, mixing the chain-extending matrix polymer and the modified temperature-sensitive color-changing microcapsules, extruding and granulating, and then casting to form the film. The temperature-induced dual-response film can realize high-temperature irreversible response and low-temperature reversible response simultaneously, and is suitable for preparing intelligent food labels or intelligent packages.

Inventors

  • ZHENG YU
  • LI YUAN
  • GUO SHAOYUN
  • Ai Jinxiang

Assignees

  • 四川大学

Dates

Publication Date
20260508
Application Date
20260127

Claims (8)

  1. 1. The preparation method of the temperature-induced dual-response film is characterized by comprising the following steps of: s1, mixing a color developing agent, a reversible thermochromic dye, a phase change regulator and a packaging material, adding water, preparing an emulsion by high-speed shearing, heating to enable the emulsion to self-assemble at a high temperature, and then sequentially carrying out suction filtration, washing and drying to obtain a temperature-sensitive thermochromic microcapsule; s2, dispersing the temperature-sensitive color-changing microcapsule in an organic solvent, and then adding a surface activation modifier to obtain a modified temperature-sensitive color-changing microcapsule; s3, mixing a matrix polymer and an epoxy chain extender, extruding and granulating to obtain a chain-extended matrix polymer; s4, mixing the chain extension matrix polymer with the modified temperature-sensitive color-changing microcapsule, extruding and granulating, and then casting to form a film to obtain the temperature-sensitive double-response film; in step S1, the encapsulation material includes polyurethane and polylactic acid; In the step S2, the surface activation modifier comprises one of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, E-44, E-51, ethylene glycol diglycidyl ether, glycerol triglycidyl ether, maleic anhydride, phthalic anhydride and pyromellitic dianhydride; in step S3, the matrix polymer is polylactic acid.
  2. 2. The method according to claim 1, wherein in the step S1, the color-developing agent comprises bisphenol A or boric acid, and the reversible thermochromic dye comprises crystal violet lactone or thermosensitive rose TF-R1.
  3. 3. The method according to claim 1, wherein in step S1, the phase-change regulator comprises paraffin or fatty acid glyceride.
  4. 4. The method according to claim 1, wherein in the step S3, the number average molecular weight of the matrix polymer is 100000g/mol to 200000g/mol.
  5. 5. A temperature-induced dual response film prepared by the method of any one of claims 1-4.
  6. 6. The thermally-responsive dual-responsive film of claim 5, wherein said chain-extended matrix polymer has a deformation response temperature greater than the response temperature of said reversible thermochromic dye for color change.
  7. 7. Use of a temperature-responsive double-responsive film as claimed in any one of claims 5-6, comprising changing said temperature-responsive double-responsive film from an initial shape to a specific shape by an applied mechanical force.
  8. 8. The method of claim 7, wherein the temperature-responsive double-responsive film is used for preparing a smart label or smart package.

Description

Preparation method of temperature-induced dual-response film, film and application thereof Technical Field The invention relates to the technical field of temperature-sensitive color-changing films, in particular to a preparation method of a temperature-sensitive dual-response film, and a film and application thereof. Background The intelligent packaging is a packaging technology for dynamically feeding back product quality information by detecting environmental conditions in food circulation and storage links, and is mainly applied to quality monitoring of perishable goods such as foods, medicines and the like. Its core function includes monitoring temperature, gaseous composition and microorganism change, promotes product security and traceability. Thermochromic materials are also called temperature-sensitive color-changing materials, and refer to materials with the color changing reversibly or irreversibly with the change of temperature, and the visible absorption spectrum of the thermochromic materials changes when the temperature rises or falls, so that the thermochromic materials have the characteristic of changing the color with the temperature. Based on this characteristic, thermochromic materials have been used in the field of intelligent food packaging, such as "Li Qingyao, min sweet, cheng Chuanxiang, etc., and various food packages prepared from thermochromic materials which have been put into production are listed in" J. Packaging engineering, 2024, 45 (13): 8-17 ", some of which can judge whether the food reaches a temperature at which it can be eaten or not according to color change, and some of which can exhibit unique patterns at a specific temperature, giving visual impact to consumers. According to whether the adopted color-changing material can respond repeatedly to change color, the thermochromic material is divided into an irreversible thermochromic material and a reversible thermochromic material, and the two materials are widely applied to the food field. For example, some foods are temperature sensitive and change in quality at elevated temperatures, so that once the temperature exceeds a limit during transportation or storage, the smart food package/label should undergo an irreversible color change to prevent bad merchants from selling spoiled foods, while for some foods the temperature does not affect their quality or generally does not reach their spoilage temperature, so that the smart food package/label is used only to indicate optimal serving temperature or only for aesthetics, which is the case with reversible thermochromic materials. Thermochromic materials are used in the field of food packaging, typically in the form of packaging films or smart labels. For example, chinese patent CN202210501954.5 provides a degradable food packaging film with thermochromic and energy-storing functions, which is prepared by adding polylactic acid resin into microcapsule thermochromic material, extruding and granulating, and blowing film, chinese patent CN202010361827.0 provides a thermo-sensitive color-changing plastic packaging film, which is prepared by adding thermo-sensitive color-changing microcapsule into layered film. However, the existing thermochromic food packaging materials have several problems: 1) The response condition and the output mode are single, and the common thermochromic food package is either reversibly or irreversibly changed in color, so that the simultaneous indication of deterioration at high temperature and proper eating temperature cannot be realized. 2) The color-changing effect is uneven, namely the shell material of the temperature-sensitive color-changing microcapsule and the matrix polymer have poor compatibility before, so that the microcapsule is unevenly dispersed in the film material, and the color is mottled during color changing, thereby affecting the beauty and uniformity. In view of the foregoing, there is a need for a temperature-induced dual-response film that can achieve both high-temperature irreversible response and low-temperature reversible response, and that is safe, nontoxic, uniform and stable in color development, and attractive. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a preparation method of a temperature-induced dual-response film, so that the industrialization of the preparation method is at least realized, and the prepared temperature-induced dual-response film can realize high-temperature irreversible response and low-temperature reversible response simultaneously. A preparation method of a temperature-induced dual-response film comprises the following steps: s1, mixing a color developing agent, a reversible thermochromic dye, a phase change regulator and a packaging material, adding water, preparing an emulsion by high-speed shearing, heating to enable the emulsion to self-assemble at a high temperature, and then sequentially carrying out suction filtration, washing and drying