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CN-122011466-A - High-thermal-stability thermal transfer release film and preparation method thereof

CN122011466ACN 122011466 ACN122011466 ACN 122011466ACN-122011466-A

Abstract

The invention discloses a high-thermal-stability thermal transfer release film and a preparation method thereof, which belong to the technical field of thermal transfer, wherein a microcrystalline cellulose natural polymer material is introduced and is used as a functional filler to participate in the crosslinking of polyimide after activation and amination modification, the microcrystalline cellulose is derived from plant fibers and can be regenerated and degraded, part of traditional petrochemical-based fillers are replaced, the dependence on nonrenewable resources is reduced, simultaneously active groups such as hydroxyl groups, amino groups and the like on the surface of the microcrystalline cellulose can form strong interactions with other components, and no additional toxic coupling agent is required to be added.

Inventors

  • SUN ZHIWU
  • WANG LI

Assignees

  • 东莞市鸿泰烫画材料有限公司

Dates

Publication Date
20260512
Application Date
20260224

Claims (10)

  1. 1. The preparation method of the high-thermal-stability thermal transfer release film is characterized by comprising the following steps of: step one, methylene dichloride is used as a solvent, free radical grafting reaction is initiated by benzoyl peroxide, alkenyl succinic anhydride is grafted onto PET molecular chains, and anhydride modified PET is obtained; Step two, performing alkali activation treatment by NaOH to obtain activated microcrystalline cellulose particles, and then performing combination and self-polymerization reaction on catechol groups of dopamine hydrochloride and surface hydroxyl groups to obtain aminated microcrystalline cellulose particles; Step three, generating polyamide acid through polycondensation reaction of 4,4 '-oxydiphthalic anhydride, 1, 3-di (4' -aminophenoxy), anhydride modified PET and aminated microcrystalline cellulose, and then imidizing at a high temperature step by step to obtain modified polyimide; and fourthly, coating pressure-sensitive adhesive on the front surface of the thermal transfer release film base film, wherein the coating speed is 80-120m/min, and curing at the temperature of 160-190 ℃ in an oven to obtain the thermal transfer release film with the thickness of 10-18 mu m and high thermal stability.
  2. 2. The preparation method of the high-thermal-stability thermal transfer release film according to claim 1, wherein the pressure-sensitive adhesive comprises the following components in parts by mass: 20-30 parts of organic silicon pressure-sensitive adhesive, 15-25 parts of dynamic cross-linked silica gel, 2-4 parts of zinc bismuth bimetallic catalyst and 1-3 parts of sodium polyacrylate.
  3. 3. The method for preparing the thermal transfer release film with high thermal stability according to claim 1, wherein the specific preparation steps of the anhydride modified PET are as follows: Adding PET slices and methylene dichloride into a reaction kettle, stirring for 10-15min at 20-25 ℃ and 500-600r/min, heating to 80-90 ℃ under the protection of nitrogen, then adding benzoyl peroxide and alkenyl succinic anhydride, continuously stirring for reacting for 3-5h, filtering, washing filter cakes with deionized water for 2-4 times respectively, and vacuum drying at 60-80 ℃ for 1-2h to obtain anhydride modified PET; the dosage ratio of the PET slice to the methylene dichloride microcrystalline cellulose particle benzoyl peroxide to the alkenyl succinic anhydride is 190-200g:450-500mL:3-4g:110-120g.
  4. 4. The method for preparing the high-thermal-stability thermal transfer release film according to claim 1, wherein the specific preparation steps of the activated microcrystalline cellulose particles are as follows: Mixing microcrystalline cellulose particles with the particle size of 20-30 mu m with NaOH, grinding for 2-4min, then placing in a reaction kettle containing deionized water, stirring and reacting for 2-4h at 100-105 ℃ and 500-600r/min, filtering, washing the precipitate with deionized water and absolute ethyl alcohol for 2-4 times, and vacuum drying for 1-2h at 60-80 ℃ to obtain activated microcrystalline cellulose particles; the dosage ratio of the microcrystalline cellulose particles, naOH and deionized water is 40-45g:3-5g:180-200mL.
  5. 5. The method for preparing the high-thermal-stability thermal transfer release film according to claim 1, wherein the preparation method of the aminated microcrystalline cellulose particles comprises the following specific steps: Adding 20-30g of activated microcrystalline cellulose particles and 120-150mL of deionized water into a reaction kettle, stirring for 30-50min at 20-25 ℃ and 500-600r/min, regulating the pH value to 7-8 by using a NaOH solution, then adding 90-100mg of dopamine hydrochloride powder and 60-80mL of absolute ethyl alcohol, continuously stirring for 24-26h under the condition of avoiding light, filtering, washing the product with deionized water and absolute ethyl alcohol for 2-4 times respectively, and drying in vacuum for 1-2h at 60-80 ℃ to obtain the aminated microcrystalline cellulose particles.
  6. 6. The method for preparing the high-thermal-stability thermal transfer release film according to claim 5, wherein the dosage ratio of the activated microcrystalline cellulose particles to deionized water to dopamine hydrochloride powder to absolute ethyl alcohol is 20-30 g/120-150 mL/90-100 mg/60-80 mL.
  7. 7. The method for preparing the high-thermal-stability thermal transfer release film according to claim 1, wherein the specific preparation steps of the modified polyimide are as follows: Adding 4,4 '-oxydiphthalic anhydride, 1, 3-di (4' -aminophenoxy) and N-methyl-2-pyrrolidone into a reaction kettle, stirring for 20-30min under the protection of nitrogen at 2-4 ℃ and 100-120r/min, heating to 20-25 ℃, continuing stirring for 4-6h, adding anhydride modified PET and aminated microcrystalline cellulose particles, continuing stirring for 10-12h, filtering, washing a filter cake with deionized water for 2-4 times, vacuum drying for 1-2h at 60-80 ℃, and heating to 105-115 ℃, 205-215 ℃, 310-320 ℃ and 350-365 ℃ to obtain modified polyimide.
  8. 8. The method for preparing a high thermal stability thermal transfer release film according to claim 5, wherein the dosage ratio of 4,4 '-oxydiphthalic anhydride, 1, 3-bis (4' -aminophenoxy), N-methyl-2-pyrrolidone, anhydride modified PET and aminated microcrystalline cellulose particles is 200-220g:400-420g:800-900ml:70-80g:10-12g.
  9. 9. The method for preparing the high-thermal-stability thermal transfer release film according to claim 1, wherein the specific preparation steps of the thermal transfer release film base film are as follows: Premixing modified polyimide and epoxidized soybean oil in a double planetary mixer for 20-30min at 80-100 ℃, heating to 170-180 ℃, and performing bidirectional gradient stretch blow molding to form a film to obtain a blend blow molding with the film thickness of 50-60 mu m to obtain a thermal transfer release film base film; The mass ratio of the modified polyimide to the epoxidized soybean oil is 50-60:2-4.
  10. 10. A high thermal stability thermal transfer release film prepared by the method of any one of claims 1-9.

Description

High-thermal-stability thermal transfer release film and preparation method thereof Technical Field The invention belongs to the technical field of thermal transfer printing, and particularly relates to a high-thermal-stability thermal transfer printing release film and a preparation method thereof. Background The heat transfer release film is a core medium substrate in a heat transfer decoration process, and has the core function of bearing the release layer, so that the release layer and the decorative pattern layer attached to the release layer are smoothly separated from the surface of the release layer in the heat transfer process under the combined action of heat and pressure, and finally, the release layer and the decorative pattern layer are completely transferred on the surface of a decorated product to form a high-quality decorative mask. In the preparation process of the thermal transfer release film, the core key step is to precisely coat a release layer on the surface of a release film substrate, and the subsequent printing pattern layer needs to be completely covered on the release layer, so that strict position adaptation requirements exist between the release film substrate and the release layer as well as between the release film substrate and the printing pattern layer. In an ideal state, the release layer on the surface of the thermal transfer release film and the pattern layer printed later should be completely overlapped, namely the sizes of the release layer and the pattern layer are kept consistent, otherwise, the pattern cannot be completely separated from the surface of the release film and transferred, and the transfer effect is affected. At present, release layer coating and subsequent pattern printing of a thermal transfer release film are usually completed by adopting gravure printing equipment, but release agents used by the release layer are transparent materials, and a color register system of the conventional gravure printing equipment cannot automatically track and position the release agents. Therefore, the coating position of the release layer on the surface of the release film substrate and the alignment of the release layer and the position of the subsequent printing pattern layer cannot be automatically controlled by means of the equipment color register system, and only the precision of gravure printing equipment and the experience guarantee of operators can be relied on. Due to the limitation of the production process, the problems of coating offset of the release layer, dislocation of the release layer and the pattern layer and the like are easy to occur, and the high-precision adaptation of the release layer coating, the release film base material and the printed pattern layer is difficult to ensure all the time. In order to avoid that the pattern layer cannot be completely printed on the release layer, the existing preparation method needs to reserve larger redundancy for the coating area of the release layer, so that the pattern layer can be completely covered in the range of the release layer. However, due to the invisibility of the release agent, the precise positioning coating of the release layer on the release film substrate cannot be realized, and finally the defects that the edge redundancy of the release layer on the surface of the thermal transfer release film is overlarge (usually about 2mm to 3 mm), pattern flash and line deformation are easily caused by irregular edge of the release layer during subsequent transfer, the release layer and the pattern layer are misplaced, pattern defects are caused, fine images and texts cannot be displayed, the aesthetic degree and packaging decoration effect of a transfer product are affected, and the rejection rate is high, so that the transfer requirement of high-precision decorative patterns is difficult to meet. Chinese patent CN119872115B announces a preparation method and application of a degradable thermal transfer lettering film, the scheme adopts premixing modified PET, dynamic thioesterified polyimide, cellulose nanocrystalline/polylactic acid hybrid material and bio-based plasticizer in a double planetary mixer, and biaxially oriented gradient stretch blow molding is carried out to form a film, but each substance in the scheme is combined through physical blending, resulting in weak interface bonding force. Disclosure of Invention The invention aims to provide a high-thermal-stability thermal transfer release film and a preparation method thereof, wherein a microcrystalline cellulose natural polymer material is introduced and is used as a functional filler to participate in the crosslinking of polyimide after being activated and aminated modification, the microcrystalline cellulose is derived from plant fibers, can be regenerated and degraded, replaces part of traditional petrochemical-based fillers, reduces the dependence on nonrenewable resources, and simultaneously has active groups such as hydroxyl grou