Near-infrared light response ester exchange resin composition as well as preparation method and application thereof

Abstract

The invention discloses a near-infrared light response ester exchange resin composition as well as a preparation method and application thereof, and relates to the field of dynamic covalent polymer materials formed by ester exchange of glass-like polymers. The composition comprises matrix resin containing an ester group, a hydroxyl-containing reactive diluent, a thermal initiator or a near-ultraviolet / visible light initiator, a near-infrared photosensitizer and a photoacid generator, the matrix resin and the reactive diluent can be polymerized under heating or irradiation of light with the wavelength of 380-780 nm to generate cured resin, and the photoacid generator is kept stable in the process; under irradiation of near-infrared light with the wavelength larger than 780 nm, the near-infrared photosensitive agent and the photoacid generator act to achieve an in-situ acid production catalytic reaction, cured resin is driven to form a dynamic covalent polymer material through ester exchange, and the dynamic covalent polymer material has the characteristic that precise space-time regulation and control can be achieved.

Description

Technical Field

[0001] This application relates to the field of vitrimer and dynamic covalent polymer materials, and particularly to a near-infrared light-responsive transesterification resin composition, its preparation method, and its application. Background Technology

[0002] Traditional thermosetting polymers possess a permanently cross-linked network structure, exhibiting excellent mechanical strength, heat resistance, and solvent resistance. However, once cured, they cannot be reprocessed, reshaped, or recycled through heating or solvents, resulting in significant resource waste. In recent years, "viscosity-like polymers" (Vitrimers), constructed by introducing dynamic covalent bonds into the polymer cross-linked network, have become a research hotspot in materials science, combining the mechanical properties of thermosetting materials with the reprocessability of thermoplastics. Among these, transesterification Vitrimers show the greatest promise for industrial application due to readily available raw materials, simple synthesis, and excellent mechanical properties.

[0003] However, existing transesterification-based Vitrimer systems suffer from the following technical bottlenecks: 1. Traditional transesterification catalysts remain active throughout resin storage and use, resulting in poor resin storage stability and difficulty in achieving spatiotemporal control of the reaction.

[0004] 2. Most existing near-infrared (NIR) response systems utilize the photothermal effect, that is, using carbon nanotubes or dyes to generate heat to heat the material as a whole. This method is essentially still heat-driven, lacks precise "on / off" control of the chemical reaction itself, and is prone to causing overall overheating and degradation of the material.

[0005] Therefore, developing a resin system that utilizes near-infrared photochemical reactions to directly generate catalysts (acids) in situ, with the curing process and transesterification process not interfering with each other and possessing excellent spatiotemporal controllability, is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the aforementioned technical issues, this invention provides a resin composition in which transesterification is driven by near-infrared light-induced photoacid-producing agent sensitized through an electron transfer mechanism. This system is designed with mutually independent "curing windows" and "dynamic reaction windows," achieving orthogonal control of material forming and dynamic rearrangement.

[0007] A first aspect of the present invention provides a near-infrared light-responsive ester exchange resin composition. The composition comprises the following components in parts by weight: 30-50 parts of matrix resin containing ester groups; 50-70 parts of reactive diluent containing hydroxyl groups; And the following components, calculated relative to the total weight of the matrix resin and reactive diluent: initiator 1-3%; near-infrared photosensitizer 0.01-0.1%; photoacid-generating agent 1-5%.

[0008] The composition exhibits the following specific reaction mechanism and curing characteristics: the initiator is selected from thermal initiators or near-ultraviolet / visible light initiators. The matrix resin and the reactive diluent can undergo free radical polymerization initiated by the initiator under heating conditions or under light irradiation with a wavelength of 380 nm to 780 nm to generate a cured resin. Under these curing conditions, the photoacid-producing agent does not decompose, thus ensuring the chemical structural stability of the cured resin in its initial state. The network structure of the cured resin retains ester and hydroxyl groups. Under near-infrared light irradiation with a wavelength greater than 780 nm, the near-infrared photosensitizer can absorb light energy and induce electron transfer in the photoacid-producing agent, thereby releasing acidic substances in situ; under the catalysis of the acid, the ester and hydroxyl groups within the cured resin network undergo transesterification reactions to form a dynamic covalent polymer material.

[0009] Furthermore, the present invention provides a preferred technical solution for the above composition: Regarding the polymerization system: the polymerization system composed of the matrix resin and the reactive diluent can be selected from any of the following as needed: (1) Acrylic ester polymerization system: The matrix resin contains at least two carbon-carbon double bonds (such as acrylate group or methacrylate group), and the reactive diluent contains carbon-carbon double bonds and hydroxyl groups, and the two undergo free radical homopolymerization or copolymerization.

[0010] (2) Thiol-olefin polymerization system: The matrix resin contains component A containing carbon-carbon double bonds and component B containing thiol groups, and the reactive diluent contains carbon-carbon double bonds and hydroxyl groups, which undergo free radical addition polymerization.

[0011] Regarding the selection of matrix resin: When an acrylate polymerization system is selected, the matrix resin includes oligomers or monomers containing two or more acrylate groups or methacrylate groups in their molecular structure; the matrix resin is preferably selected from at least one of polyester acrylate, polyether acrylate, polyurethane acrylate, epoxy acrylate, alkyd resin acrylate or polyol acrylate.

[0012] When a thiol-olefin polymerization system is selected, component A is a compound containing two or more carbon-carbon double bonds, and component B is a compound containing two or more thiol groups (-SH).

[0013] Specifically, the matrix resin or component A may be selected from glycerol 1,3-diglyceryl alcohol diacrylate (GDGDA), 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, bisphenol A diglycidyl ether diacrylate, ethoxylated bisphenol A diacrylate, etc.; and component B may be selected from pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP), trimethylolpropane tris(3-mercaptopropionate) (TMPMP), ethylene glycol di(3-mercaptopropionate) (GDMP), etc.

[0014] Regarding the selection of reactive diluents: The reactive diluent containing hydroxyl groups is preferably selected from at least one of 2-hydroxy-3-phenoxypropyl acrylate (HPPA), 2-hydroxyethyl acrylate (HEA), 2-hydroxyethyl methacrylate (HEMA), 2-hydroxypropyl acrylate (HPA), pentaerythritol triacrylate (PETA), and dipentaerythritol pentaacrylate.

[0015] In addition, the reactive diluent may also be a mixture of the above-mentioned hydroxyl-containing monomer and non-hydroxyl-containing monomer. The non-hydroxyl-containing monomer may be selected from 1,6-hexanediol diacrylate (HDDA), trimethylolpropane triacrylate (TMPTA), ethylene glycol diglycidyl ether, tripropylene glycol diacrylate (TPGDA), etc., to adjust the viscosity and mechanical properties of the system.

[0016] Regarding the selection of initiators: the initiators are selected by choosing specific light absorption bands or thermal decomposition temperatures to avoid the sensitive regions of photoacid-producing agents. (1) Visible light initiator: a compound that absorbs in the 380nm-500nm wavelength range, selected from any one or combination of the following: acylphosphine oxides, diacetic titanium derivatives or thioxanthones; preferably selected from bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO / 819), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), bis(2,6-difluoro-3-(1-hydropyrrole-1-yl)phenyl)diacetic titanium (Irgacure 784).

[0017] (2) Thermal initiator: The thermal initiator is selected from any one or combination of the following: azo compounds or organic peroxide compounds; preferably selected from azobisisobutyronitrile (AIBN) and benzoyl peroxide (BPO).

[0018] Regarding near-infrared photosensitizers and acid-producing agents: The near-infrared photosensitizer includes heptamethine cyanine dyes, the molecular structure of which contains two nitrogen-containing heterocycles and a polymethyl chain connecting the nitrogen-containing heterocycles; preferably, the near-infrared photosensitizer is S2025 dye, or a compound having the following characteristics: , Where R1 is one or more short-chain alkanes having 2-5 carbon atoms. R2 is either a hydrogen group or a chlorine group. Where Z is one of the following structures: , Where X - It is one of the following structures: .

[0019] The photoacid-producing agent is selected from iodonium salts, thiodonium salts, or sulfonate compounds; preferably selected from at least one of 4-isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, (4-methoxyphenyl)phenyliodonium trifluoromethanesulfonate, and (4-isopropylphenyl)(4-methylphenyl)iodonium hexafluorophosphate; the photoacid-producing agent and the near-infrared photosensitizer undergo electron transfer to release acid under near-infrared light irradiation.

[0020] In a second aspect, the present invention provides a method for preparing a near-infrared light-responsive ester exchange resin composition. The method comprises the following steps: (1) mixing a matrix resin containing ester groups and an active diluent containing hydroxyl groups in proportion to a uniform amount according to the formulation; (2) adding an initiator, stirring and dispersing evenly; (3) adding a near-infrared photosensitizer and a photoacid-generating agent under light-protected conditions, and dispersing evenly to obtain a resin composition; (4) curing and molding: placing the resin composition in a mold and curing it by irradiation with visible light at a wavelength of 380 nm to 780 nm or by heating at a temperature of 60 °C to 90 °C to obtain a cured resin containing a potential acid catalyst.

[0021] In a preferred embodiment, the visible light irradiation in step (4) uses an LED light source with a center wavelength of 405 nm and a light intensity of 10 mW / cm²-2000 mW / cm²; or, the heating and curing temperature in step (4) is controlled at 65℃-85℃. These conditions ensure that the photoacid-producing agent remains stable and does not decompose during the resin network construction process.

[0022] A third aspect of the present invention provides applications of the aforementioned near-infrared light-responsive transesterification resin composition. These applications include 3D printing materials, shape memory materials, self-healing materials, and recyclable materials. The core of the application method lies in applying near-infrared light with a wavelength greater than 780 nm to a localized or overall cured resin. This causes a near-infrared photosensitizer to induce electron transfer in a photoacid-producing agent, generating acidic substances and driving a transesterification reaction within the resin network. This results in rearrangement of the material's internal topology, plastic reprocessing, or interlayer welding.

[0023] The beneficial effects of this application are: 1. Orthogonal controllability: By utilizing the separation of the wavelength / energy of "visible light / low temperature" curing and "near-infrared light" acid production, complete decoupling of molding and dynamic functions is achieved.

[0024] 2. Deep penetration: Near-infrared light has excellent tissue and material penetration, solving the problem that ultraviolet light cannot solidify thick samples.

[0025] 3. Storage stability: The photoacid-generating agent remains inert before being exposed to near-infrared light irradiation, and the resin system has good storage stability. Attached Figure Description

[0026] Figure 1 The UV-Vis absorption spectra of the system components in Example 1 are shown. Figure 2 The photodispersive spectra of the system components in Example 1 under an 808 nm light source are shown. Figure 3 Thermogravimetric analysis (TGA) spectrum of the photocurable resin prepared in Example 1; Figure 4 Dynamic mechanical characterization (DMA) spectrum of the vitrimer prepared in Example 2; Figure 5 Dynamic mechanical characterization (DMA) spectrum of the vitrimer prepared in Example 3; Figure 6 Dynamic mechanical characterization (DMA) spectrum of the vitrimer prepared in Example 4; Figure 7 Dynamic mechanical characterization (DMA) spectrum of the photocurable polymer prepared for Comparative Example 1. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description of this application, in conjunction with its embodiments, provides a clear and complete overview. These embodiments are merely some examples of this application; other embodiments obtained by those skilled in the art based on these embodiments without inventive effort are all within the scope of protection of this application.

[0028] Example 1 A near-infrared light-responsive transesterification photocurable resin composition comprises the following components: reactive diluent 2-hydroxy-3-phenoxypropyl acrylate (HPPA), matrix resin (glycerol 1,3-diglyceryl glycol diacrylate (GDGDA) and pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP)), photoinitiator bis(2,6-difluoro-3-pyrrolephenyl)titanium (784), photoacid generator 4-isobutylphenyl-4'-methylphenyl iodohexafluorophosphate (iodonium salt GR250), and IR dye (S2025). The composition is as follows: HPPA:GDGDA:PETMP in a mass ratio of 5:3:1; the photoinitiator and photoacid generator each account for 2% of the total mass of the reactive diluent and the matrix resin; and the IR dye accounts for 0.05% of the total mass of the reactive diluent and the matrix resin.

[0029] Among them, the IR dye S2025, as a near-infrared photosensitizer, has the following structural formula:

[0030] A method for preparing a near-infrared light-responsive transesterification photocurable resin includes the following steps: (1) Weigh out the active diluent (HPPA), glycerol 1,3-diglycerol dipropionate (GDGDA), and pentaerythritol tetrakis(3-mercaptopropionic acid) (PETMP) according to the weight parts, and add them all to the beaker for mixing. Because glycerol 1,3-diglycerol dipropionate (GDGDA) has a high viscosity, place the beaker under a magnetic stirrer at 45°C and stir for 30 minutes to mix evenly.

[0031] (2) Weigh out photoinitiator 784 according to the weight parts, add it after the resin system in step (1) is mixed evenly, mechanically stir and premix for 2 minutes, and then ultrasonically disperse for 15 minutes to fully disperse the initiator in the resin.

[0032] (3) Weigh out iodonium salt GR250 and IR dye S2025 according to the weight parts, add them to the mixture system of step (2) under the dark, mechanically stir and premix for 2 minutes, and then ultrasonically disperse for 15 minutes to fully disperse them in the resin. After complete dispersion, they need to be vacuum degassed and then sealed and refrigerated.

[0033] (4) Inject the resin from step (3) into a polytetrafluoroethylene mold (sample thickness 2 mm), place it in an LED UV curing machine for curing, and after complete curing, post-cur in an oven at 100-120℃ for 1-2 hours; the LED UV curing wavelength is 405 nm, and the light source intensity is 2000 mW / cm². 2The resin is 100mm away from the light source.

[0034] The system used in this embodiment was subjected to ultraviolet-visible absorption spectroscopy (UV-vis) and thermogravimetric analysis (TGA), and the results are shown below: Figure 1 The UV-Vis absorption spectra of the IR dye S2025, iodonium salt GR250, and photoinitiator 784 in the system are shown in the figure. It can be seen from the figure that the photoinitiator 784 has absorption at 405 nm, which can generate free radical initiation of resin system polymerization; the iodonium salt GR250 has no absorption at 405 nm, which proves that it will not decompose during the UV curing process; the obvious absorption peak at 808 nm is attributed to dye S2025, which proves that the material can respond to 808 nm near-infrared light.

[0035] Figure 2 The image shows the photolysis spectrum of the system under an 808 nm light source. It can be seen from the figure that the peak value at 808 nm decreases significantly with increasing illumination time. Accompanying this is the decrease in absorbance of iodonium salt GR250 at 235 nm with illumination time, and the increase in absorbance at 575 nm. This proves that a photochemical reaction occurred under 808 nm light source irradiation, realizing an electron transfer catalytic acid production reaction.

[0036] Figure 3 The TGA characterization of the photocured sample obtained in step (4) shows that the material has excellent thermal stability before 250°C.

[0037] Example 2 A near-infrared light-responsive transesterification glass polymer (vitrimer)

[0038] A near-infrared light-responsive transesterified glass polymer was obtained by irradiation with an 808 nm wavelength near-infrared light source, based on the preparation method described in the examples.

[0039] This application eliminates the need for adding nanoparticles, reducing the filler load in the system and solving the problem of uneven mixing of nanoparticles in the system.

[0040] By utilizing the absorption characteristics of the IR dye S2025 in the near-infrared band, electron transfer catalysis for acid production is achieved, enabling precise in-situ release of the catalyst and driving the transesterification of Vitrimer.

[0041] In addition to the IR dye S2025, other near-infrared dyes can also be considered. Based on the absorption characteristics, a suitable wavelength of near-infrared light source can be selected for irradiation. In this embodiment, the IR dye S2025 is selected, and an 808nm wavelength near-infrared light source is used for irradiation. The light intensity is 4W, and the distance between the light source and the material surface is 30mm~100mm.

[0042] Near-infrared dyes are excited to an excited state after absorbing light energy. The excited-state dyes transfer energy to the iodonium salt via electron transfer. The free radical ion pairs formed in this process are unstable and further generate protons (H+). + This leads to acid production. Under high temperature and acidic catalysis, topological rearrangement occurs inside the material, resulting in transesterification.

[0043] The system used in this embodiment was characterized by dynamic mechanical analysis (DMA), and the results are as follows: Figure 4 The graph shows the stress relaxation curves of the material after irradiation with an 808 nm light source for different durations. The test was conducted at 100 °C. The time corresponding to the stress relaxation of the sample to 1 / e of the initial value is the characteristic relaxation time. As can be seen from the graph, the sample cannot relax effectively without near-infrared irradiation. After irradiation for 20 min, the relaxation time is 900 s, and after irradiation for 30 min, the relaxation time is 298 s. This shows that the relaxation time of the sample at the same temperature decreases with increasing irradiation time, verifying that the 808 nm excited dye and iodonium salt achieve electron transfer and produce acid to catalyze the transesterification reaction.

[0044] Example 3 A near-infrared light-responsive transesterification photocurable resin composition comprises the following components: reactive diluents 2-hydroxy-3-phenoxypropyl acrylate (HPPA) and trimethylolpropane triacrylate (TMPTA), matrix resins (glycerol 1,3-diglyceryl glycol diacrylate (GDGDA) and 1,6-hexanediol diacrylate (HDDA), photoinitiator 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), photoacid generator 4-isobutylphenyl-4'-methylphenyl iodohexafluorophosphate (iodonium salt GR250), and IR dye (S2025). The mass ratio of HPPA:TMPTA:GDGDA:HDDA is 3:3:3:1, the photoinitiator and photoacid generator each account for 1% of the total mass, and the dye accounts for 0.03% of the total mass.

[0045] The cured resin was prepared according to the same steps as in Example 1. The system used in this example was then characterized by dynamic mechanical analysis (DMA) after irradiation with a near-infrared light source. The results are as follows: Figure 5The figure shows the stress relaxation curves of the material before and after irradiation with an 808 nm light source. The test was conducted at 100 °C. The figure shows that the relaxation time of the sample without near-infrared irradiation was 603 s, while after 30 min of irradiation, the relaxation time decreased to 56 s. This demonstrates that near-infrared irradiation excited the topological rearrangement of the material structure, resulting in a shorter relaxation time compared to the unirradiated sample. This verifies the applicability of the 808 nm excited dye to the acid-catalyzed transesterification reaction catalyzed by electron transfer with iodonium salt in acrylate systems and under different initiator conditions.

[0046] Example 4 A near-infrared light-responsive transesterification photocurable resin composition comprises the following components: reactive diluent 2-hydroxy-3-phenoxypropyl acrylate (HPPA), matrix resins (glycerol 1,3-diglyceryl glycol diacrylate (GDGDA) and 1,6-hexanediol diacrylate (HDDA), thermal initiator azobisisobutyronitrile (AIBN), photoacid generator 4-isobutylphenyl-4'-methylphenyl iodohexafluorophosphate (iodonium salt GR250), and IR dye (S2025). The mass ratio of HPPA:GDGDA:HDDA is 5:3:1, the thermal initiator and photoacid generator each account for 1% of the total mass, and the dye accounts for 0.03% of the total mass.

[0047] The cured resin is prepared according to the following steps: (1) Weigh out the active diluent (HPPA), glycerol 1,3-diglycerol diacrylate (GDGDA), and 1,6-hexanediol diacrylate (HDDA) according to the weight parts, and add them all to the beaker for mixing. Because glycerol 1,3-diglycerol diacrylate (GDGDA) has a high viscosity, place the beaker under a magnetic stirrer at 45°C and stir for 30 minutes to mix evenly.

[0048] (2) Weigh out the thermal initiator AIBN according to the weight parts, add it after the resin system in step (1) is mixed evenly, mechanically stir and premix for 2 minutes, and then ultrasonically disperse for 15 minutes to fully disperse the initiator in the resin.

[0049] (3) Weigh out iodonium salt GR250 and IR dye S2025 according to the weight parts, add them to the mixture system of step (2) under the dark, mechanically stir and premix for 2 minutes, and then ultrasonically disperse for 15 minutes to fully disperse them in the resin. After complete dispersion, they need to be vacuum degassed and then sealed and refrigerated.

[0050] (4) Inject the resin from step (3) into a polytetrafluoroethylene mold (sample thickness 2 mm) and place it in an 80°C oven to cure for 1 hour.

[0051] The system used in this embodiment was then characterized by dynamic mechanical analysis (DMA) after irradiation with a near-infrared light source. The results are as follows: Figure 6 The figure shows the stress relaxation curves of the material before and after irradiation with an 808 nm light source. The test was conducted at 100 °C. The figure shows that near-infrared irradiation excited the topological rearrangement of the material structure, and the relaxation time was shortened compared to the unirradiated sample. This verifies the applicability of the thermally initiated transesterification reaction catalyzed by electron transfer between the 808 nm excited dye and iodonium salt.

[0052] Comparative Example 1 A photocurable resin composition without near-infrared photosensitizer comprises the following components: reactive diluent 2-hydroxy-3-phenoxypropyl acrylate (HPPA), matrix resins (glycerol 1,3-diglyceryl glycol diacrylate (GDGDA) and pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP)), photoinitiator bis(2,6-difluoro-3-pyrrolephenyl)titanium (784), and photoacid-producing agent 4-isobutylphenyl-4'-methylphenyliodohexafluorophosphate (iodonium salt GR250). The mass ratio of HPPA:GDGDA:PETMP is 5:3:1, and the photoinitiator and photoacid-producing agent each account for 2% of the total mass.

[0053] The resin was cured in the same manner as in Example 1, and the cured samples were characterized by near-infrared light excitation and dynamic mechanical analysis (DMA). The results are as follows: Figure 7 The figure shows the stress relaxation curves of the material before and after irradiation with an 808 nm light source. The test was conducted at 100 °C. The figure shows that the relaxation rate of the sample without photosensitizer did not change at the same temperature, verifying that near-infrared photosensitization for acid production cannot be achieved without a dye photosensitizer, and that the photothermal effect alone is insufficient to trigger acid production from iodonium salts.

[0054] The matrix resin can also be a resin system that, after polymerization, produces saturated / unsaturated polyester, polyester acrylate, polyurethane acrylate, or epoxy-acrylate.

[0055] The ester-containing matrix resin described in this application may contain ester groups not only in the matrix resin itself, but also in additives such as crosslinking agents in the resin system.

[0056] The initiator can be a photoinitiator or a thermal initiator. The photoinitiator can also be a benzophenone, a thioxanthone (such as isopropyl thioxanthone), an acylphosphine oxide (such as phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide), an aryl iodonium salt or an aryl sulfonium salt, or a cationic photoinitiator (such as triarylsulfonium hexafluorophosphate). It can also be an initiator containing an acyl group, a ketone group or an aromatic ketone structure (such as 2-hydroxy-2-methyl-1-phenyl-1-propanone).

[0057] Thermal initiators can be selected from azo compounds such as azobisisobutyronitrile (AIBN) and organic peroxides such as benzoyl peroxide.

[0058] In addition to the aforementioned IR dyes, the near-infrared photosensitizers described in this application also include various cyanine, squaricine, and phthalocyanine dyes that absorb near-infrared light, or dyes containing lanthanide ions (such as Nd). 3+ Yb 3+ Er 3+ Ho 3+ Metal complexes of ).

[0059] The photo-induced acid-producing agents described in this application also include iodonium salts such as diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, p-methoxyphenylphenyliodonium salt, and 4-isopropyldiphenyliodonium hexafluorophosphate; sulfonium salts such as triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, tris[4-(2-methyl-2-morpholino)phenyl]sulfonium hexafluorophosphate, triethylsulfonium salt, and triisopropylsulfonium salt; and sulfonate precursors such as p-toluenesulfonate and trifluoromethanesulfonate.

[0060] The above embodiments are merely illustrative of the invention and are not intended to limit the implementation. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A near-infrared light-responsive ester exchange resin composition, characterized in that: Includes the following components by weight: 30-50 parts of matrix resin containing ester groups; 50-70 parts of reactive diluent containing hydroxyl groups; And the following components, calculated relative to the total weight of the matrix resin and the reactive diluent: initiator 1-3%; near-infrared photosensitizer 0.01-0.1%; photoacid-producing agent 1-5%; The initiator is selected from thermal initiators or near-ultraviolet / visible light initiators; the matrix resin and the reactive diluent can be free radical polymerized by the initiator under heating conditions or under light irradiation with a wavelength of 380nm~780nm to generate a cured resin, and the photoacid-producing agent does not decompose under these conditions; the network structure of the cured resin retains ester groups and hydroxyl groups; under near-infrared light irradiation with a wavelength greater than 780nm, the near-infrared photosensitizer can induce the photoacid-producing agent to undergo electron transfer and release acid in situ, driving the cured resin to form a dynamic covalent polymer material through transesterification reaction.

2. The near-infrared light-responsive ester exchange resin composition according to claim 1, characterized in that: The polymerization system composed of the matrix resin and the reactive diluent is selected from any one of the following: (1) Acrylic ester polymerization system: the matrix resin contains at least two carbon-carbon double bonds, the reactive diluent contains carbon-carbon double bonds and hydroxyl groups, and the two undergo free radical homopolymerization or copolymerization of carbon-carbon double bonds under the action of an initiator; (2) Thiol-olefin polymerization system: The matrix resin contains component A containing carbon-carbon double bonds and component B containing thiol groups, and the reactive diluent contains carbon-carbon double bonds and hydroxyl groups. The two undergo free radical addition polymerization under the action of an initiator.

3. The near-infrared light-responsive ester exchange resin composition according to claim 2, characterized in that: When (1) acrylate polymerization system is selected, the matrix resin includes oligomers or monomers containing two or more acrylate groups or methacrylate groups in the molecular structure; preferably selected from at least one of polyester acrylate, polyether acrylate, polyurethane acrylate, epoxy acrylate, alkyd resin acrylate or polyol acrylate. When the (2) mercapto-olefin polymerization system is selected, component A is a compound containing two or more carbon-carbon double bonds in its molecular structure, and component B is a compound containing two or more mercapto groups in its molecular structure.

4. The near-infrared light-responsive ester exchange resin composition according to claim 3, characterized in that: The matrix resin or component A is selected from at least one of glycerol 1,3-diglyceryl alcohol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, bisphenol A diglycidyl ether diacrylate, and ethoxylated bisphenol A diacrylate; component B is selected from at least one of pentaerythritol tetrakis(3-mercaptopropionic acid) ester, trimethylolpropane tris(3-mercaptopropionate), and ethylene glycol di(3-mercaptopropionate).

5. The near-infrared light-responsive ester exchange resin composition according to claim 1, characterized in that: The hydroxyl-containing reactive diluent is selected from at least one of 2-hydroxy-3-phenoxypropyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, pentaerythritol triacrylate, and dipentaerythritol pentaacrylate; or, the reactive diluent is a mixture of the above-mentioned hydroxyl-containing monomer and hydroxyl-free monomer, wherein the hydroxyl-free monomer is selected from at least one of 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, ethylene glycol diglycidyl ether, and tripropylene glycol diacrylate.

6. The near-infrared light-responsive ester exchange resin composition according to claim 1, characterized in that: The photoinitiator has absorption in the 380nm~500nm wavelength range and is selected from any one or combination of the following: acylphosphine oxide compounds, diacetic titanium derivatives, or thioxanthone compounds; preferably selected from bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and bis(2,6-difluoro-3-(1-hydropyrrole-1-yl)phenyl)diacetic titanium. Alternatively, the thermal initiator may be selected from any one or combination of the following: azo compounds or organic peroxide compounds; preferably selected from azobisisobutyronitrile and benzoyl peroxide.

7. The near-infrared light-responsive ester exchange resin composition according to claim 1, characterized in that: The near-infrared photosensitizer includes heptamethine cyanine dyes, the molecular structure of which contains two nitrogen-containing heterocycles and a polymethyl chain connecting the nitrogen-containing heterocycles; preferably, the near-infrared photosensitizer is S2025 dye, or a compound having the following characteristics: ， Where R1 is one or more short-chain alkanes having 2 to 5 carbon atoms. R2 is either a hydrogen group or a chlorine group. Where Z is one of the following structures: ， Where X - It is one of the following structures: 。 8. The near-infrared light-responsive ester exchange resin composition according to claim 1, characterized in that: The photoacid-producing agent is selected from iodonium salts, thiodonium salts, or sulfonate compounds; preferably selected from at least one of 4-isobutylphenyl-4'-methylphenyliodonium hexafluorophosphate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, (4-methoxyphenyl)phenyliodonium trifluoromethanesulfonate, and (4-isopropylphenyl)(4-methylphenyl)iodonium hexafluorophosphate; the photoacid-producing agent and the near-infrared photosensitizer undergo electron transfer to release acid under near-infrared light irradiation.

9. A method for preparing a near-infrared light-responsive ester exchange resin composition, characterized in that, Includes the following steps: (1) According to the weight proportions of claim 1, the matrix resin containing ester groups and the active diluent containing hydroxyl groups are mixed evenly in proportion; (2) According to the proportions of claim 1, an initiator is added, stirred and dispersed evenly; (3) Under light-protected conditions, a near-infrared photosensitizer and a photoacid generator are added and dispersed evenly to obtain a resin composition; (4) Curing and molding: The resin composition of step (3) is placed in a mold and cured by visible light irradiation with a wavelength of 380nm~780nm or by heating at a temperature of 60℃~90℃ to obtain a cured resin containing a potential acid catalyst.

10. The preparation method according to claim 9, characterized in that: In step (4), the visible light irradiation uses an LED light source with a center wavelength of 405nm and a light intensity of 10mW / cm²~2000mW / cm²; in step (4), the heating curing temperature is 65℃~85℃.

11. The application of a near-infrared light-responsive ester exchange resin composition, characterized in that: The cured resin prepared using the composition according to any one of claims 1-8 or the method according to any one of claims 9-10 is applied to the fields of 3D printing materials, shape memory materials, self-healing materials or recyclable materials; the application method includes: applying near-infrared light with a wavelength greater than 780nm to the local area or the whole of the cured resin, so that the near-infrared photosensitizer induces the photoacid-producing agent to undergo electron transfer to produce acidic substances, and drives the ester exchange reaction in the resin network in conjunction with the thermal effect, thereby realizing the rearrangement of the internal topology of the material, plastic reprocessing or interlayer welding.

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