Polyfluoropolyurethane acrylate prepolymers, low-dielectric polyfluoropolyurethane acrylate inks for inkjet 3D printing, their preparation methods and applications

Abstract

This invention provides a polyfluoropolyurethane acrylate prepolymer, a polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing, its preparation method, and its application. It relates to the technical field of polymer materials. This invention uses a polyfluoropolyurethane acrylate containing photocurable groups as a prepolymer, which is compounded with a photoinitiator and reactive diluent monomers to obtain a low-dielectric ink for inkjet 3D printing. After inkjet printing, the ink is photocured to obtain a cured material with the desired shape and structure. This cured material has excellent mechanical properties, good thermal stability and heat resistance, as well as low dielectric constant and dielectric loss, and can be applied in high-tech fields such as microelectronics and communications.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a polyfluoropolyurethane acrylate prepolymer, a polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing, its preparation method and application. Background Technology

[0002] Inkjet 3D printing technology is widely used in the fabrication of electronic devices due to its high printing precision, non-contact printing, solvent-free UV curing, environmental friendliness, ease of operation, and one-step molding capabilities. However, with the rise of microelectronics and the advent of the 5G era, mobile communication networks are gradually transitioning towards low latency, low power consumption, and high transmission rates. Therefore, from the perspective of reducing operating power consumption and signal reception delay, requirements have been placed on the dielectric properties of photosensitive inks for inkjet 3D printing. The lower the dielectric constant and dielectric loss, the lower the signal delay and the less power consumption generated by the circuit. At the same time, due to the high precision of inkjet 3D printing, which requires low ink viscosity, it is also necessary to consider the flexible and controllable molecular weight of prepolymers and the ink formulation design to reduce the ink viscosity as much as possible without compromising the mechanical properties of the ink.

[0003] Given the above background, designing photosensitive resin structures with lower dielectric constants and dielectric losses is a top priority. The dielectric constant of photosensitive resins can be reduced through several measures. One approach is to introduce low-polarization groups such as CF bonds, CH bonds, and alicyclic structural units to reduce the dipole strength and number of the material, thereby lowering the polarizability (Journal of Materials Science: Materials in Electronics (2019) 30: 18297–18305). Another approach is to introduce large-volume rigid groups to increase the free volume of the resin, thus reducing the dielectric constant. For example, Ludi Shi et al. designed and synthesized a weakly polarized cyclohexyl monomer, 1,4-bis(4-fluorobenzoyl)cyclohexane (DFBCH), as the main reactant to reduce the dipole polarization rate and dielectric constant of polyaryletherketone (PAEK) resin. They added large-volume fluorene groups to increase the free volume of the resin, further reducing the dielectric constant. Furthermore, hydroquinone, with its symmetrical and regular structure, can be used to enhance the regularity of molecular chains and reduce dipole relaxation, thereby further reducing the dielectric constant and dielectric loss of the resin. Additionally, since air has a dielectric constant of 1, air can be incorporated into the material by introducing micropores, increasing the porosity of the matrix, reducing the material density, and decreasing the number of polarized molecules per unit volume, thus significantly reducing the dielectric constant. For example, Chongyang Zhang et al. prepared a porous polyethersulfone film using the breath diagram method, utilizing the porous structure to reduce the dielectric constant of the system to meet the needs of electronic packaging materials (Polym Int 2021; 70:1456–146). The dielectric properties of resins can be improved by adding organic-inorganic hybrid fillers. For example, Qiuxia Peng et al. developed novel BCB-functionalized organic-inorganic hybrid microspheres (BMPS). By doping 2 wt% BMPS, the dielectric constant of divinylsiloxane-dibenzocyclobutene (DVSBCB) resin was significantly reduced, and BMPS and DVSBCB resin showed perfect compatibility (Polym. Chem., 2023, 14, 3446–3452). Another example is Chao Huang et al., who introduced a novel aminopropyl isobutyl polysilsesquioxane (POSS) with single-vertex activity through in-situ polymerization, which reduced the dielectric constant of PI-POSS nanocomposites to below 2.6. At the same time, the prepared PI-POSS nanocomposites also have excellent mechanical properties, good heat resistance and thermal stability, highlighting the huge market prospects of 5G chip packaging and millimeter-wave antennas in the future (Macromol. Mater. Eng. 2019, 304, 19005).

[0004] In summary, the above measures to improve the dielectric properties of photosensitive resins reveal that while introducing large-volume rigid groups can reduce the dielectric constant, it increases the viscosity of the ink, which does not meet the requirements of inkjet 3D printing. Introducing porous structures involves complex process control and may introduce unnecessary impurities, affecting the overall performance of the resin. Modification with inorganic nanoparticles can lead to uneven particle dispersion in the system, causing agglomeration and consequently deteriorating performance. Summary of the Invention

[0005] The purpose of this invention is to provide a polyfluoropolyurethane acrylate prepolymer, a polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing, its preparation method, and its applications. This invention uses a polyfluoropolyurethane acrylate containing photocurable groups as a prepolymer, which is compounded with a photoinitiator and reactive diluent monomers to obtain a low-dielectric ink for inkjet 3D printing. After inkjet printing, the ink is photocured to obtain a cured material with the desired shape and structure. This cured material possesses excellent mechanical properties, good thermal stability and heat resistance, as well as low dielectric constant and dielectric loss, and can be applied in high-tech fields such as microelectronics and communications.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a polyfluoropolyurethane acrylate prepolymer, the structural formula of which is shown below:

[0008]

[0009] Wherein, R includes One of them;

[0010] n = 1-5.

[0011] Furthermore, the molecular weight of the polyfluorinated polyurethane acrylate prepolymer is 1000-3500.

[0012] The present invention also provides a method for preparing the polyfluoropolyurethane acrylate prepolymer as described above, characterized by comprising the following steps:

[0013] Under a protective atmosphere, polyfluorinated diols, diisocyanate monomers and catalysts are placed in a container and heated for reaction.

[0014] After the heating reaction is complete, 2-hydroxyethyl acrylate is added to the container for a cooling reaction; a solvent is added during the cooling reaction to prevent cross-linking of the polymerization product;

[0015] After the cooling reaction is complete, solvent is added to dissolve the polymerization product and obtain a mixture. The mixture is then dried to obtain a polyfluoropolyurethane acrylate prepolymer.

[0016] Furthermore, the heating reaction conditions include: a heating temperature of 50–80°C and a heating reaction time of 2–6 hours;

[0017] And / or, the cooling reaction conditions include: a cooling temperature of 40–55°C and a cooling reaction time of 2–4 hours;

[0018] Preferably, the solvent is added when the temperature is lowered to 48-52°C, more preferably 50°C;

[0019] And / or, the polyfluorinated diol comprises 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecane-1,11-diol;

[0020] And / or, the diisocyanate monomer includes one of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexanediisocyanate and terephthalic diisocyanate;

[0021] And / or, the solvent includes one or more of acetone, chloroform, tetrahydrofuran, and dioxane;

[0022] And / or, the catalyst includes one or more of organotin catalysts, amine catalysts, and metal catalysts;

[0023] Preferably, the organotin catalyst comprises dibutyltin dilaurate or stannous octoate;

[0024] Preferably, the amine catalyst comprises diethylenetriamine or bis(dimethylaminoethyl) ether;

[0025] Preferably, the metal catalyst comprises potassium isooctanoate;

[0026] Preferably, the protective atmosphere includes one of nitrogen, argon, or helium.

[0027] Furthermore, the molar ratio of the diisocyanate monomer to the polyfluorinated diol is 1.10 to 1.50:1;

[0028] And / or, the molar ratio of 2-hydroxyethyl acrylate to diisocyanate monomer is 0.30 to 0.69:1;

[0029] And / or, taking polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate as a whole, the equivalence relationship between the total volume of solvent added during the cooling reaction and the total volume of solvent added after the cooling reaction and the total mass of polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate is (2.0~4.0ml):1g;

[0030] And / or, taking polyfluorinated diol, diisocyanate and 2-hydroxyethyl acrylate as a whole, the organotin catalyst accounts for 0.8% to 2% of the total mass of polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate;

[0031] And / or, the number of repeating units of polyfluorinated diols and diisocyanates in the main chain of the polyfluorinated polyurethane acrylate prepolymer is 1 to 5.

[0032] The present invention also provides a low dielectric ink of polyfluorinated polyurethane acrylate for inkjet 3D printing, comprising, by mass fraction: 5 wt%-15 wt% of polyfluorinated polyurethane acrylate prepolymer prepared by the method described above or the method described above for preparing polyfluorinated polyurethane acrylate prepolymer, 1 wt%-10 wt% of photoinitiator, and 75 wt%-93 wt% of diluent monomer.

[0033] Furthermore, the diluent monomers include 4-acryloylmorpholine, tricyclic [5.2.1.02,6] sebacate diacrylate, tris(2-acryloyloxyethyl) isocyanurate, and 1,10-bis(acryloyloxy)decane;

[0034] Preferably, the low-dielectric ink for inkjet 3D printing, based on polyfluorinated polyurethane acrylate, comprises, by mass fraction: 5 wt%-15 wt% polyfluorinated polyurethane acrylate prepolymer, 1 wt%-10 wt% photoinitiator, 5-25 wt% 4-acryloylmorpholine, 5-25 wt% tricyclo[5.2.1.02,6] sebacic acid diacrylate, 48-51 wt% tris(2-acryloyloxyethyl) isocyanurate, and 5-25 wt% 1,10-bis(acryloyloxy)decane;

[0035] Preferably, tris(2-acryloyloxyethyl) isocyanurate accounts for 48 wt% of the total ink mass;

[0036] And / or, the photoinitiator comprises one or more of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, triarylthionium hexafluorophosphate, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and ethyl 2,4,6-trimethylbenzoylphosphonate, preferably comprising 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

[0037] This invention also provides a method for preparing a polyfluorinated polyurethane acrylate low-dielectric ink for inkjet 3D printing, comprising the following steps:

[0038] The polyfluoropolyurethane acrylate prepolymer, diluent monomer, and photoinitiator were stirred and mixed under light-protected conditions, and after degassing treatment, a polyfluoropolyurethane acrylate low dielectric ink for inkjet 3D printing was obtained.

[0039] Preferably, the bubble extraction process is ultrasonication and vacuuming.

[0040] The present invention also provides a curing material, wherein the curing material is prepared by inkjet printing using the polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing described above or the polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing prepared by the method described above.

[0041] Furthermore, the glass transition temperature T of the cured material g The temperature ranges from 160 to 230℃.

[0042] And / or, the tensile strength of the cured material is 45-70 MPa, and the elongation at break is 5%-15%;

[0043] And / or, the dielectric constant of the cured material is 2.40 to 2.90 at 20 GHz, and the dielectric loss is 0.010 to 0.020 at 20 GHz.

[0044] This invention provides a fluoropolyurethane acrylate prepolymer, a polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing, its preparation method, and its application. The beneficial effects are as follows:

[0045] This invention utilizes photocurable polyfluoropolyurethane acrylate as a prepolymer, which is compounded with reactive diluent monomers and photoinitiators to obtain UV-curable inks for 3D printing. These inks are then printed using inkjet printing to obtain cured materials of the desired shapes and structures. The Tc of the cured material... g The temperature range is 160–230℃, the tensile strength is 45–70 MPa, the elongation at break is 5%–15%, the dielectric constant at 20 GHz is 2.50–3.00, and the dielectric loss at 20 GHz is 0.010–0.020. Attached Figure Description

[0046] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0047] Figure 1The 1H NMR spectrum of the two-step feeding method for synthesizing the end-capped polyurethane acrylate (FPUA-IPDI) with isophorone diisocyanate structure in the main chain, as shown in Example 1 of this invention.

[0048] Figure 2 The GPC diagram shows the two-step feeding method used to synthesize the end-capped polyfluoropolyurethane acrylate (FPUA-IPDI) with an isophorone diisocyanate structure in the main chain, which was prepared in Example 1 of this invention.

[0049] Figure 3 In Example 1 of the present invention, the infrared spectra of the reaction before the addition of 2-hydroxyethyl acrylate for 3 hours, 2 hours and 2 hours after the addition of 2-hydroxyethyl acrylate were obtained during the second capping reaction.

[0050] Figure 4 The infrared spectra of the prepolymer-terminated polyfluorinated polyurethane acrylate low dielectric ink with isophorone diisocyanate structure in the main chain of the inkjet 3D printing prepolymer prepared in Example 1 of the present invention before and after different curing processes.

[0051] Figure 5 The infrared spectra of the prepolymer-terminated polyfluorinated polyurethane acrylate low dielectric ink with isophorone diisocyanate structure in the main chain of the inkjet 3D printing prepolymer prepared in Example 2 of the present invention before and after different curing processes.

[0052] Figure 6 The infrared spectra of the prepolymer-terminated polyfluorinated polyurethane acrylate low dielectric ink with isophorone diisocyanate structure in the main chain of the inkjet 3D printing prepolymer prepared in Example 3 of the present invention before and after different curing processes.

[0053] Figure 7 The infrared spectra of the prepolymer-terminated polyfluorinated polyurethane acrylate low dielectric ink with isophorone diisocyanate structure in the main chain of the inkjet 3D printing prepolymer prepared in Example 4 of the present invention before and after different curing processes.

[0054] Figure 8 The temperature-viscosity curves of the prepolymer-terminated polyfluorinated polyurethane acrylate low dielectric ink with isophorone diisocyanate structure in the main chain of the inkjet 3D printing prepolymer prepared in Examples 1-4 of this invention are shown.

[0055] Figure 9 The shear rate-viscosity curves of the prepolymer-terminated polyfluorinated polyurethane acrylate low dielectric ink with isophorone diisocyanate structure in the main chain of the inkjet 3D printing prepolymer prepared in Examples 1-4 of this invention are shown.

[0056] Figure 10The TGA curves of the end-capped polyfluorinated polyurethane acrylate low-dielectric ink with isophorone diisocyanate structure in the main chain of the prepolymer for inkjet 3D printing prepared in Examples 1-4 of this invention after thermosetting. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0058] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0059] According to a first aspect of the present invention, a polyfluoropolyurethane acrylate prepolymer is provided, the structural formula of which is shown below:

[0060]

[0061] Wherein, R includes One of them;

[0062] n = 1-5.

[0063] Specifically, in this invention, a UV-curable polyfluorinated polyurethane acrylate is selected as the prepolymer because the polyurethane acrylate molecule contains urethane hard segments, which can impart good mechanical and thermal properties to the photocured material, and the unsaturated double bonds in the acrylate groups enable the polymer to have photocuring ability.

[0064] As an optional embodiment of the present invention, the molecular weight of the polyfluoropolyurethane acrylate prepolymer is 1000-3500 (e.g., 1500, 2000, 2500, 3000, etc.).

[0065] Specifically, the polyfluorinated polyurethane acrylate prepolymer provided by the present invention can be used to prepare ink for inkjet 3D printing. The polyfluorinated polyurethane acrylate low dielectric ink for inkjet 3D printing is a solvent-free system and requires low viscosity and surface tension. The viscosity of the prepolymer is closely related to its molecular weight. The lower the molecular weight, the lower the viscosity of the prepolymer. Therefore, the molecular weight of the polyfluorinated polyurethane acrylate prepolymer prepared by the present invention is preferably controlled within 1000 to 3500.

[0066] According to a second aspect of the present invention, a method for preparing the above-mentioned polyfluoropolyurethane acrylate prepolymer is provided, comprising the following steps:

[0067] Under a protective atmosphere, polyfluorinated diols, diisocyanate monomers and catalysts are placed in a container and heated for reaction.

[0068] After the heating reaction is complete, 2-hydroxyethyl acrylate is added to the container for a cooling reaction;

[0069] Solvents are added during the cooling reaction to prevent cross-linking of the polymerization products;

[0070] After the cooling reaction is complete, solvent is added to dissolve the polymerization product and obtain a mixture. The mixture is then dried to obtain a polyfluoropolyurethane acrylate prepolymer.

[0071] Specifically, since the first step of this invention is a polymerization process, the addition of solvent will reduce the polymerization reaction rate. Therefore, no solvent is added in the first step. During the cooling process after the first step reaction is completed, an appropriate amount of solvent is added to prevent gelation in subsequent reactions.

[0072] Specifically, the 2-hydroxyethyl acrylate used in this invention is the end-capping agent. After the polymerization reaction of polyfluorinated diol and diisocyanate is carried out for 2 to 6 hours, the temperature should be lowered to 48-52°C, preferably 50°C, and then an appropriate amount of solvent should be added before continuing the end-capping reaction.

[0073] As an optional embodiment of the present invention, the heating reaction conditions include: a heating temperature of 60-80°C (e.g., 65°C, 70°C, 75°C, etc.) and a heating reaction time of 2-6 hours (e.g., 2 hours, 3 hours, 4 hours, 5 hours, etc.).

[0074] As an optional embodiment of the present invention, the cooling reaction conditions include: a cooling temperature of 40-55°C (e.g., 40°C, 45°C, 50°C, etc.) and a cooling reaction time of 2-4 hours (e.g., 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, etc.).

[0075] Preferably, the solvent is added when the temperature is lowered to 48-52°C, more preferably 50°C.

[0076] Specifically, the reaction end time in this invention is determined by observing the changes in reactive groups through Fourier transform infrared spectroscopy at different time points during the reaction process.

[0077] As an optional embodiment of the present invention, the polyfluorinated diol includes 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecane-1,11-diol;

[0078] Specifically, the introduction of fluorine atoms in polyfluorinated diols is beneficial for reducing molar polarizability, and fluorine atoms can increase free volume, which also helps to reduce the dielectric constant of inkjet 3D printing inks. Therefore, it is selected as a prepolymer component in inkjet 3D printing ink formulations.

[0079] And / or, the diisocyanate monomer includes one of toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HMDI) and terephthalic diisocyanate.

[0080] And / or, the solvent includes one or more of acetone, chloroform, tetrahydrofuran, and dioxane;

[0081] And / or, the catalyst includes one or more of organotin catalysts, amine catalysts, and metal catalysts;

[0082] Preferably, the organotin catalyst comprises dibutyltin dilaurate or stannous octoate;

[0083] Preferably, the amine catalyst comprises diethylenetriamine or bis(dimethylaminoethyl) ether;

[0084] Preferably, the metal catalyst comprises potassium isooctanoate;

[0085] Preferably, the protective atmosphere includes one of nitrogen, argon, or helium.

[0086] As an optional embodiment of the present invention, the molar ratio of the diisocyanate monomer to the polyfluorinated diol is 1.10 to 1.50:1 (e.g., 1.15:1, 1.25:1, 1.30:1, 1.40:1);

[0087] And / or, the molar ratio of 2-hydroxyethyl acrylate to diisocyanate monomer is 0.30 to 0.69:1 (e.g., 0.35, 0.45, 0.50, 0.60);

[0088] And / or, taking polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate as a whole, the equivalence relationship between the total volume of solvent added during the cooling reaction and the total mass of polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate and the total mass of polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate is (2.0~4.0ml):1g (e.g. 2.0ml:1g, 2.5ml:1g, 3.5ml:1g, 4.0ml:1g);

[0089] And / or, taking the polyfluorinated diol, diisocyanate and 2-hydroxyethyl acrylate as a whole, the catalyst accounts for 0.8 to 2% (e.g., 1.2%, 1.4%, 1.6%, 1.8% etc.) of the total mass of the polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate.

[0090] Specifically, this invention strictly controls the molar ratio of diisocyanate to polyfluorinated diol to be 1.10–1.50:1 to ensure the formation of linear oligomers with NCO end groups during the heating reaction. This also ensures the polymer reaches a pre-set molecular weight. Finally, end-capping is achieved by reacting the hydroxyl groups in 2-hydroxyethyl acrylate with the unreacted isocyanate groups at both ends of the prepolymer. The polyurethane acrylate prepolymer prepared by this method has the characteristics of controllable molecular weight, low viscosity, and good solubility. In addition to these advantages, the presence of urethane hard segments obtained from the polyaddition reaction of hydroxyl and isocyanate groups also endows it with superior mechanical properties.

[0091] As an optional embodiment of the present invention, the number of repeating units of polyfluorinated diol and diisocyanate in the main chain of the polyfluorinated polyurethane acrylate prepolymer is 1 to 5.

[0092] Specifically, since the molecular weight of the polyfluorinated polyurethane acrylate prepolymer prepared by this invention should be controlled within the range of 1000 to 3500, the number of repeating units of polyfluorinated diol and diisocyanate in the main chain of the prepolymer is between 1 and 5.

[0093] According to a third aspect of the present invention, a low-dielectric ink of polyfluorinated polyurethane acrylate for inkjet 3D printing is provided, comprising, by mass fraction: 5 wt%-15 wt% (e.g., 8 wt%, 10 wt%, 12 wt%, etc.) of polyfluorinated polyurethane acrylate prepolymer prepared by the method described above, 1 wt%-10 wt% (e.g., 2 wt%, 4 wt%, 6 wt%, 8 wt%, etc.) of photoinitiator, and 75 wt%-93 wt% (e.g., 75 wt%, 78 wt%, 82 wt%, 86 wt%, 90 wt%, etc.) of diluent monomer.

[0094] Specifically, the present invention limits the proportion of the prepared polyfluorinated polyurethane acrylate prepolymer to 5wt%-15wt% of the total mass of the ink. If it exceeds 15wt%, the viscosity of the prepared ink will be too high, and if it is less than 5wt%, it will affect the mechanical properties of the ink.

[0095] As an optional embodiment of the present invention, the diluent monomers include 4-acryloylmorpholine, tricyclic [5.2.1.02,6] sebacate diacrylate, tris(2-acryloyloxyethyl) isocyanurate and 1,10-bis(acryloyloxy)decane.

[0096] Specifically, 4-acryloylmorpholine is a monofunctional diluent monomer with a viscosity of only 12 cps at 25°C, which can reduce the viscosity of the ink and make it suitable for inkjet 3D printing.

[0097] Tris(2-acryloyloxyethyl) isocyanurate has trifunctionality (one monomer has three acrylate groups, which are three reactive sites). Each acrylate group can crosslink and cure with other acrylate diluent monomers, thereby increasing the crosslink density of the system. At the same time, it can also drive the curing of the prepolymer during the curing process, forming a dense crosslink network between them.

[0098] The tricyclic [5.2.1.02,6] sebacate diacrylate contains a tricyclic structure that can enhance the rigidity of the molecular chain, increase the hardness of the photocurable material, and endow the photocurable material with superior mechanical properties.

[0099] The long-chain structure of 1,10-bis(acryloyloxy)decane endows the photocurable material with a certain degree of flexibility and significantly increases its elongation at break. Furthermore, the long chain of this monomer differs from the CO ether bond structure of the traditional diluent monomer polyethylene glycol diacrylate; the C-C bonds have lower polarity, which can improve the dielectric properties of the cured material to some extent.

[0100] As an optional embodiment of the present invention, the low dielectric ink of polyfluorinated polyurethane acrylate for inkjet 3D printing comprises, by mass fraction: 5wt%-15wt% polyfluorinated polyurethane acrylate prepolymer, 1wt%-10wt% photoinitiator, 5-25wt% 4-acryloylmorpholine, 5-25wt% tricyclo[5.2.1.02,6] sebacic acid diacrylate, 48-51wt% tris(2-acryloyloxyethyl) isocyanurate, and 5-25wt% 1,10-bis(acryloyloxy)decane;

[0101] Preferably, tris(2-acryloyloxyethyl) isocyanurate accounts for 48 wt% of the total ink mass.

[0102] Specifically, this invention limits the proportion of tris(2-acryloyloxyethyl) isocyanurate to 48-51 wt% of the total mass of the ink. This allows the prepared photocurable material to have superior mechanical properties. If its proportion is higher than 51 wt%, the crosslinking density of the system will be too high during the curing process, which will reduce the flexibility of the photocurable material and make it brittle. If its proportion is lower than 48 wt%, the crosslinking density of the system will be too low, which will prevent the cured material from achieving the best mechanical properties.

[0103] Furthermore, based on the fact that the proportion of the polyfluorinated polyurethane acrylate prepolymer prepared in this invention accounts for 5wt%-15wt% of the total mass of the ink, the dielectric properties of the ink can be controlled by adjusting the proportion of 1,10-bis(acryloyloxy)decane and tricyclic [5.2.1.02,6] sebacic acid diacrylate in the total mass of the ink. Specifically, when the content of 1,10-bis(acryloyloxy)decane is set to be higher within the specified numerical range (5-25wt%), the dielectric constant of the ink is lower.

[0104] This invention adjusts the viscosity of the ink system, the flexibility of the photocurable material, and the dielectric properties by selecting the above four diluent monomers and changing their ratio.

[0105] And / or, the photoinitiator comprises one or more of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide (TPO), triarylhexafluorophosphate thioonium salt, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and ethyl 2,4,6-trimethylbenzoylphosphonate, preferably comprising 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

[0106] Specifically, the present invention uses a variety of diluent monomers, which can reduce the viscosity of ink mixtures while imparting superior mechanical properties to the inks. At the same time, each triazine ring of the triazine monomer of isocyanurate tri(2-acryloyloxyethyl) ester in the ink formulation has three acrylate groups, providing three crosslinking sites and increasing the crosslinking density of the system. Furthermore, the carbon-carbon double bond structure in the diluent monomers can increase the photocurability of the ink mixture. During curing, it can drive the prepolymer to cure, forming a dense crosslinked network between them, which synergistically enhances the performance of the ink material.

[0107] As a preferred embodiment of the present invention, the low dielectric ink of polyfluorinated polyurethane acrylate for inkjet 3D printing comprises, by mass fraction: 5wt%-15wt% polyfluorinated polyurethane acrylate prepolymer, 1wt%-10wt% 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 5-25wt% 4-acryloylmorpholine, 5-25wt% tricyclo[5.2.1.02,6] sebacate diacrylate, 48-51wt% tri(2-acryloyloxyethyl) isocyanurate, and 5-25wt% 1,10-bis(acryloyloxy)decane.

[0108] Furthermore, the photoinitiator can cause the low dielectric ink provided by the present invention to crosslink and cure under ultraviolet light. Since both the diluent monomer and the photoinitiator in the ink system provided by the present invention contain morpholino groups, the α hydrogen attached to the tertiary amine structure of the morpholino group can be reactivated and continue to cure by utilizing the principle of reaction between the α hydrogen and the peroxy group, so the ink provided by the present invention does not exhibit oxygen inhibition during the photocuring process, and therefore does not require the addition of an oxygen scavenger.

[0109] When traditional inks undergo free radical photocuring in air, the presence of oxygen will form peroxy groups with the free radicals, thereby inhibiting curing and making the surface of the cured material sticky. This affects the curing effect of the ink and the final performance of the cured material. Therefore, oxygen scavengers, such as triethanolamine, are usually added.

[0110] According to a fourth aspect of the present invention, a method for preparing the above-mentioned polyfluorinated polyurethane acrylate low-dielectric ink for inkjet 3D printing is provided, comprising the following steps:

[0111] The polyfluoropolyurethane acrylate prepolymer, diluent monomer, and photoinitiator were stirred and mixed under light-protected conditions, and then subjected to defoaming treatment to obtain a polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing.

[0112] Specifically, the present invention utilizes photocurable polyfluorinated polyurethane acrylate as a prepolymer, and combines it with reactive diluent monomers and photoinitiators to obtain UV-curable ink for 3D printing.

[0113] And / or, the bubble extraction process is ultrasonication and vacuuming.

[0114] According to a fifth aspect of the present invention, a curing material is provided, said curing material being prepared by inkjet printing using the aforementioned polyfluorinated polyurethane acrylate low-dielectric ink for inkjet 3D printing.

[0115] As an optional embodiment of the present invention, the glass transition temperature T of the cured material is... gThe temperature range is 160–230℃ (e.g., 170℃, 180℃, 200℃, 220℃, etc.), the tensile strength is 45–70 MPa (e.g., 50 MPa, 60 MPa, 65 MPa, etc.), the elongation at break is 5%–15% (e.g., 6%, 8%, 10%, 12%, 14%, etc.), the dielectric constant of the cured material at 20 GHz is 2.40–2.90 (e.g., 2.50, 2.60, 2.70, 2.80, etc.), and the dielectric loss at 20 GHz is 0.010–0.020 (e.g., 0.012, 0.014, 0.016, 0.018, etc.).

[0116] The present invention will now be described in further detail with reference to specific embodiments and comparative examples.

[0117] First, it should be noted that the raw materials used in the following preparation examples and embodiments are from the following sources:

[0118] 1H,1H,11H,11H-Perfluoro-3,6,9-trioxaundecane-1,11-diol: Aladdin, analytical grade;

[0119] Toluene diisocyanate (TDI): supplied by Dalian Baolimo New Materials Co., Ltd., with a purity of 99 wt%;

[0120] Isophorone diisocyanate (IPDI): Sigma-Aldrich, analytical grade;

[0121] 4,4'-Diphenylmethane diisocyanate (MDI): Xilong Chemical Plant, analytical grade;

[0122] 1,6-Hexanediisocyanate (HMDI): Sigma-Aldrich, chromatographic grade;

[0123] 4-Acryloylmorpholine: Aladdin, analytical grade;

[0124] Tricyclic [5.2.1.02,6] sebacate diacrylate: Aladdin, analytical grade;

[0125] Tris(2-acryloyloxyethyl) isocyanurate: Aladdin, analytical grade;

[0126] 1,10-bis(acryloyloxy)decane: Aladdin, analytical grade;

[0127] Dibutyltin dilaurate (DBTDL): Aladdin, analytical grade;

[0128] Stannous octoate: Aladdin, analytical grade; 1-Hydroxycyclohexylphenyl ketone: Macklin, analytical grade;

[0129] Acetone: Fuyu Fine Chemical Co., Ltd., analytical grade;

[0130] Aladdin, analytical grade;

[0131] Chloroform: Aladdin, analytical grade;

[0132] Tetrahydrofuran: Aladdin, analytical grade

[0133] Example 1: A two-step feeding method for synthesizing a capped polyfluoropolyurethane acrylate (FPUA-IPDI, structural formula below) with an isophorone diisocyanate structure in the main chain, comprising:

[0134]

[0135] Taking the synthesis of the 2000 molecular weight prepolymer FPUA-IPDI as an example: In a 100ml three-necked flask equipped with a mechanical stirrer, a spherical condenser, and a nitrogen inlet, add 5.0133g (0.0122mol) of the polyfluorinated monomer 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecan-1,11-diol, 3.8645g (0.0174mol) of isophorone diisocyanate (IPDI), and 0.08ml of the catalyst dibutyltin dilaurate (DBTDL). Under continuous... Under a nitrogen or argon atmosphere, the temperature was slowly increased to 65°C and reacted for 3 hours. 1.1605 ml (0.011 mol) of 2-hydroxyethyl acrylate (HEA) was precisely added using a pipette. As the temperature decreased to 50°C, 10 ml of acetone was added promptly to prevent polymer crosslinking. After reacting for 2 hours, 30 ml of acetone was added to dissolve the prepolymer. The resulting liquid was dried in an 80°C forced-air oven to finally obtain a capped polyfluoropolyurethane acrylate (FPUA-IPDI) with a main chain containing an isophorone diisocyanate structure; the yield was 83%.

[0136] The 1H NMR spectrum, GPC spectrum, and infrared spectra of the second-step capping reaction (3 hours before addition of 2-hydroxyethyl acrylate, 2 hours after addition, and 2 hours after addition) are shown below. Figure 1 , Figure 2 and Figure 3 ; among them from Figure 1 The 1H NMR spectrum shows that the ratio of the peak area of ​​the -NH2 group to the C=C double bond of the grafted 2-hydroxyethyl acrylate is 2 / (1-0.4), where 0.4 is the peak area of ​​the ungrafted 2-hydroxyethyl acrylate C=C double bond. Based on this, the number of repeating units in the prepolymer, n = 3.33, is calculated, and the absolute molecular weight of the prepolymer is 2559. Figure 2The GPC plot shows that the relative molecular weight of the prepolymer is 3283, which is quite similar to the results, proving the successful synthesis of low molecular weight FPUA-IPDI. From Figure 3 The three infrared spectra obtained from the reactions before HEA addition (2 hours), before HEA addition (3 hours), and after HEA addition (2 hours) show that the 2267 cm⁻¹ value is higher when 2-hydroxyethyl acrylate is added and reacted. -1 The characteristic absorption peak of -NCO (isocyanate group) has disappeared, proving that the end capping is complete.

[0137] Preparation Example 2: A method for preparing a prepolymer main chain containing a toluene diisocyanate structure-terminated polyfluoropolyurethane acrylate (FPUA-TDI, structural formula below), comprising:

[0138]

[0139] Taking the synthesis of the 2500 molecular weight prepolymer FPUA-TDI as an example: In a 100ml three-necked flask equipped with a mechanical stirrer, a spherical condenser, and a nitrogen inlet, 5.8785g (0.0143mol) of the polyfluorinated monomer 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecan-1,11-diol, 3.2250g (0.0185mol) of toluene diisocyanate (TDI), and 0.08ml of catalyst stannous octoate were added. Under a continuous nitrogen or argon atmosphere, the mixture was slowly... The temperature was slowly increased to 65℃ and reacted for 3 hours. 0.9284 ml (0.009 mol) of 2-hydroxyethyl acrylate (HEA) was precisely added using a pipette, and 10 ml of dioxane solvent was added promptly to prevent polymer crosslinking. The temperature was lowered to 50℃ and the reaction was stopped after 2 hours. 30 ml of dioxane solvent was added to dissolve the prepolymer. The resulting liquid was dried in an 80℃ forced-air oven to finally obtain a capped polyfluoropolyurethane acrylate (FPUA-TDI) with a main chain containing toluene diisocyanate structure; the yield was 81%.

[0140] Preparation Example 3: A method for preparing a prepolymer main chain containing a 4,4'-diphenylmethane diisocyanate structure-terminated polyfluoropolyurethane acrylate (FPUA-MDI, structural formula below), comprising:

[0141]

[0142] Taking the synthesis of the 3000 molecular weight prepolymer FPUA-MDI as an example: In a 100ml three-necked flask equipped with a mechanical stirrer, a spherical condenser, and a nitrogen inlet, add 5.2118g (0.0127mol) of the polyfluorinated monomer 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecan-1,11-diol, 4.0546g (0.0162mol) of 4,4'-diphenylmethane diisocyanate (MDI), and 0.08ml of catalyst stannous octoate. Under a continuous nitrogen or argon atmosphere, slowly... The reaction was carried out at 65°C for 3 hours. 0.7737 ml (0.0073 mol) of 2-hydroxyethyl acrylate (HEA) was precisely added using a pipette, and 10 ml of tetrahydrofuran solvent was added promptly to prevent polymer crosslinking. The reaction was stopped after the temperature was lowered to 50°C for 2 hours. 30 ml of tetrahydrofuran solvent was added to dissolve the prepolymer. The resulting liquid was dried in an 80°C oven to obtain a capped polyfluoropolyurethane acrylate (FPUA-MDI) with a main chain containing a 4,4'-diphenylmethane diisocyanate structure; the yield was 75%.

[0143] Preparation Example 4: A method for preparing a prepolymer main chain containing a 1,6-hexamethylene diisocyanate (HMDI) end-capped polyfluoropolyurethane acrylate (FPUA-HMDI, structural formula below), comprising:

[0144]

[0145] Taking the synthesis of the 3500 molecular weight prepolymer FPUA-HMDI as an example: In a 100ml three-necked flask equipped with a mechanical stirrer, a spherical condenser, and a nitrogen inlet, add 6.2806g (0.0153mol) of the polyfluorinated monomer 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecan-1,11-diol, 3.0868g (0.0184mol) of 1,6-hexamethylene diisocyanate (HMDI), and 0.08ml of the catalyst dibutyltin dilaurate (DBTDL). Under a continuous nitrogen atmosphere, the temperature was slowly increased to 65°C and reacted for 3 hours. 0.6631 ml (0.0063 mol) of 2-hydroxyethyl acrylate (HEA) was precisely added using a pipette, and 10 ml of chloroform was added promptly to prevent polymer crosslinking. The temperature was lowered to 50°C and the reaction was stopped after 2 hours. 30 ml of acetone was added to dissolve the prepolymer. The resulting liquid was dried in an 80°C oven to obtain a capped polyfluoropolyurethane acrylate (FPUA) with a main chain containing a 1,6-hexamethylene diisocyanate structure; the yield was 73%.

[0146] Table 1 is a summary table of the amount of each reactant added in Preparation Examples 1-4:

[0147] Table 1

[0148]

[0149] The total solvent volume refers to the total volume of solvent added during and after the cooling process.

[0150] Examples 1-4

[0151] The preparation method of polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing is as follows:

[0152] The total mass of the ink mixture was set to 10g. For each of the four groups, 0.5g (5% of the total ink mass) of the prepolymer (FPUA-IPDI) synthesized by the two-step feeding method prepared in Preparation Example 1, containing isophorone diisocyanate structure in its main chain, 4.8g (48% of the total ink mass) of tris(2-acryloyloxyethyl) isocyanurate, and 0.2g (2% of the total ink mass) of the photoinitiator 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone were accurately weighed. Groups 1-4 were then further weighed with 0.5g, 1.0g, 1.5g, and 2.0g of 1,10-bis(acryloyloxy)decane (representing 5%, 10%, 15%, and 20% of the total ink mass, respectively). Figure 8-9 The ingredients refer to FPUA-5B, FPUA-10B, FPUA-15B, and FPUA-20B, respectively. Tricyclic [5.2.1.02,6] sebacic acid diacrylate 2.5g, 2.25g, 2g, and 1.75g ​​(representing 25%, 22.5%, 20%, and 17.5% of the total ink mass, respectively) are added. The remaining component is 4-acryloylmorpholine (representing 15%, 12.5%, 10%, and 7.5% of the total ink mass, respectively). The weighed reagents are added to a 20ml sample bottle. Under light-protected conditions, the components are thoroughly mixed using magnetic stirring. After mixing, the magnetic stirring is removed, and the ink is degassed using ultrasound and vacuum. Once no more bubbles appear in the ink, the ink preparation is complete. The ink is then stored in a light-protected environment for later use.

[0153] The low-dielectric ink prepared in Example 1 was named FPUA-5B; the low-dielectric ink prepared in Example 2 was named FPUA-10B; the low-dielectric ink prepared in Example 3 was named FPUA-15B; and the low-dielectric ink prepared in Example 4 was named FPUA-20B.

[0154] Figure 4-7 The infrared spectra of the prepolymer-terminated polyfluorinated polyurethane acrylate low-dielectric inks with isophorone diisocyanate structures in the main chain, prepared in Examples 1-4 of this invention, after different curing processes (before UV curing, after UV curing, and after UV and thermal curing), show that after UV curing, the 1640 cm⁻¹ of the prepolymer used for inkjet 3D printing is... -1The C=C characteristic absorption peak at the point has basically disappeared. After the system has undergone thermal curing, the characteristic absorption peak has completely disappeared, indicating that the system has successfully completed the photo- and thermal curing process, and that thermal curing plays a certain auxiliary role in UV curing.

[0155] Figure 8-9 The temperature-viscosity curves and shear rate-viscosity curves of the end-capped polyfluorinated polyurethane acrylate low-dielectric inks with isophorone diisocyanate structures in the prepolymer main chain for inkjet 3D printing prepared in Examples 1-4 of this invention are shown respectively. The shear rate-viscosity curves show that the ink viscosity does not change with the shear rate, indicating that the ink is a Newtonian fluid. The temperature-viscosity curves show that the viscosity of the inks in Examples 1-4 has dropped to below 60 mPa·s in the 40-50℃ range, and the inks meet the viscosity requirements for inkjet printing when the print head is heated.

[0156] Figure 10 The TGA curves of the cured materials obtained by inkjet printing and photo- and thermo-curing of the prepolymer main chain containing isophorone diisocyanate structure of the low dielectric ink of polyfluorinated polyurethane acrylate prepared in Examples 1-4 of this invention are shown. It can be seen from the curves that after UV light and thermo-curing, the 5% thermal decomposition temperature of the film is 214-303℃, which has excellent thermal stability.

[0157] Examples 5-8

[0158] The difference between Examples 5-8 and Examples 1-4 is that the long-chain diluent monomer 1,10-bis(acryloyloxy)decane added to Groups 5-8 accounts for 25%, 22.5%, 20%, and 17.5% of the total ink mass, respectively, and the tricyclic [5.2.1.02,6] sebacic acid diacrylate accounts for 5%, 10%, 15%, and 20% of the total ink mass, respectively, while the contents of the remaining components are the same as those in Examples 1-4.

[0159] Example 9

[0160] The difference between this embodiment and Example 1 is that 0.5g of the prepolymer with a toluene diisocyanate structure-terminated end-capped polyfluoropolyurethane acrylate (FPUA-TDI) obtained in Preparation Example 2 was added; otherwise, the same as in Example 1 was used.

[0161] Example 10

[0162] The difference between this embodiment and Example 1 is that 0.5g of the prepolymer with a 4,4'-diphenylmethane diisocyanate structure in its main chain, prepared in Example 3, was added. All other aspects are the same as in Example 1.

[0163] Example 11

[0164] The difference between this embodiment and Example 1 is that 0.5g of the prepolymer with a 1,6-hexamethylene diisocyanate (HMDI) structure in the main chain obtained in Preparation Example 4 was added; otherwise, the same as in Example 1 was used.

[0165] Comparative Example 1

[0166] The difference between Comparative Example 1 and Examples 1-4 is that the mass of added tris(2-acryloyloxyethyl) isocyanurate is 6.8 g (68% of the total ink mass), and the masses of the remaining components are as follows: 0.6 g of 4-acryloylmorpholine (6% of the total ink mass), 0.9 g of 1,10-bis(acryloyloxy)decane (9% of the total ink mass), 1.2 g of tricyclic [5.2.1.02,6] sebacic acid diacrylate (12% of the total ink mass), 0.3 g of the two-step feeding method prepolymer synthesized in Example 1 with an isophorone diisocyanate-terminated end-capped polyfluoropolyurethane acrylate (FPUA-IPDI) containing an isophorone diisocyanate structure in its main chain. The mass of the photoinitiator is the same as in Examples 1-4.

[0167] Comparative Example 2

[0168] The difference between Comparative Example 2 and Examples 1-4 is that the added tris(2-acryloyloxyethyl) isocyanurate is 2.8 g (28% of the total ink mass), and the masses of the remaining components are: 1.4 g of 4-acryloylmorpholine (14% of the total ink mass), 2.1 g of 1,10-bis(acryloyloxy)decane (21% of the total ink mass), 2.8 g of tricyclic [5.2.1.02,6] sebacic acid diacrylate (28% of the total ink mass), 0.7 g of the two-step feeding method prepolymer synthesized in Example 1 with an isophorone diisocyanate-containing end-capped polyfluoropolyurethane acrylate (FPUA-IPDI) structure in the main chain, and the mass of the photoinitiator is the same as in Examples 1-4.

[0169] Comparative Example 3

[0170] The difference between Comparative Example 3 and Examples 1-4 is that 2.5 g of the two-step feeding method prepolymer synthesized in Preparation Example 1, containing an isophorone diisocyanate structure in its main chain, is added (accounting for 25% of the total ink mass). The masses of the remaining components are as follows: 0.8 g of 4-acryloylmorpholine (accounting for 8% of the total ink mass), 1.2 g of 1,10-bis(acryloyloxy)decane (accounting for 12% of the total ink mass), 1.5 g of tricyclo[5.2.1.02,6] sebacic acid diacrylate (accounting for 15% of the total ink mass), and 3.8 g of tri(2-acryloyloxyethyl) isocyanurate (accounting for 38% of the total ink mass). The mass of the photoinitiator is the same as in Examples 1-4.

[0171] Note: The mass fractions of each component in Comparative Examples 1-3 are based on the low dielectric ink (FPUA-15B) prepared in the corresponding Example 3.

[0172] Table 2 is a summary table of the amount of each reactant added in Examples 1-11 and Comparative Examples 1-3:

[0173] Table 2

[0174]

[0175] Performance testing

[0176] The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing prepared in Examples 1-11 of this invention was uniformly coated onto a clean glass plate using a doctor blade. After 60 seconds of UV irradiation, it was thermally cured under curing conditions of 180℃ / 2h and 200℃ / 2h to obtain a cured material. The cured material was a thin film with a length of 20cm, a width of 15cm, and a thickness of 70-90μm. Differential scanning calorimetry (DSC) was performed on the film (specific test conditions: using a TA Q20 instrument, heating from 30℃ to 300℃ at a rate of 10K / min, with nitrogen gas introduced at a flow rate of 50ml / min), tensile properties (specific test conditions: using an AnInstron-5869 machine, a load of 500N, a strain rate of 2mm / min, with an effective tensile length of 20mm and a width of 6mm), and dielectric properties (specific test conditions: using an Aglient...). The dielectric properties were measured using an E4980A impedance analyzer, and the dielectric constant and dielectric loss were recorded in the frequency range of 0.001-10GHz at 30℃. The test results are shown in Tables 3 and 4.

[0177] Table 3 shows the dielectric properties of the films prepared with the inks from Examples 1-11.

[0178]

[0179] Table 4 shows the tensile and heat resistance properties of the films prepared with the inks from Examples 1-11.

[0180]

[0181]

[0182] As can be seen from the dielectric constant variation of the cured films at 20 GHz in Table 3, the dielectric constant decreases with increasing content of the long-chain diluent monomer 1,10-bis(acryloyloxy)decane. Furthermore, comparing the dielectric constants of the cured films obtained from the inks of Preparation Examples 1-4 and 5-8 reveals that, since 1,10-bis(acryloyloxy)decane is a long-chain diluent monomer, it has lower polarity compared to long chains linked by carbon-oxygen bonds. Therefore, increasing the content of the long-chain diluent monomer 1,10-bis(acryloyloxy)decane is more effective in reducing the dielectric constant than increasing the content of tricyclic [5.2.1.02,6] sebacic acid diacrylate.

[0183] As can be seen from Table 4, the introduction of the long-chain diluent monomer 1,10-bis(acryloyloxy)decane results in an elongation at break of 5-15% for the cured material. At the same time, the high content of trifunctional triazine rings improves the heat resistance and tensile strength of the cured material, giving it excellent comprehensive performance.

[0184] As can be seen from Tables 3 and 4, compared with Examples 1-4, Comparative Example 1 had a lower flexibility and lower elongation at break due to the excessive amount of added tris(2-acryloyloxyethyl) isocyanurate, which accounted for 68% of the total mass of the ink.

[0185] As can be seen from Tables 3 and 4, compared with Examples 1-4, Comparative Example 2 has a lower elastic modulus and tensile strength due to the insufficient amount of added tris(2-acryloyloxyethyl) isocyanurate, which accounts for 28% of the total ink mass. At the same time, the heat resistance of the cured material is also reduced due to the decrease in the content of the rigid triazine ring.

[0186] Compared with Examples 1-4, Comparative Example 3 had an excessive amount of added prepolymer FPUA-IPDI, accounting for 25% of the total ink mass, resulting in excessively high ink viscosity, which did not meet the low viscosity requirements for inkjet printing. Table 4 also shows that the introduction of too much low molecular weight prepolymer also reduced the heat resistance of the cured material.

[0187] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-dielectric ink based on polyfluorinated polyurethane acrylate for inkjet 3D printing, characterized in that, By mass fraction, it includes: 5wt%-15wt% polyfluoropolyurethane acrylate prepolymer, 1wt%-10wt% photoinitiator, and 75wt%-93wt% diluted monomer; The structural formula of the polyfluoropolyurethane acrylate prepolymer is shown below: Wherein, R includes One of them; n＝1-5。 2. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 1, characterized in that, The molecular weight of the polyfluoropolyurethane acrylate prepolymer is 1000-3500.

3. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 1, characterized in that, The preparation method of the polyfluoropolyurethane acrylate prepolymer includes the following steps: Under a protective atmosphere, polyfluorinated diols, diisocyanate monomers and catalysts are placed in a container and heated for reaction. After the heating reaction is complete, 2-hydroxyethyl acrylate is added to the container for a cooling reaction; a solvent is added during the cooling reaction to prevent cross-linking of the polymerization product; After the cooling reaction is complete, solvent is added to dissolve the polymerization product and obtain a mixture. The mixture is then dried to obtain a polyfluoropolyurethane acrylate prepolymer.

4. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 3, characterized in that, The heating reaction conditions include: a heating temperature of 60–80°C and a heating reaction time of 2–6 hours; And / or, the cooling reaction conditions include: a cooling temperature of 40–55°C and a cooling reaction time of 2–4 hours; And / or, the polyfluorinated diol comprises 1H,1H,11H,11H-perfluoro-3,6,9-trioxaundecane-1,11-diol; And / or, the diisocyanate monomer includes one of toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, isophorone diisocyanate, 1,6-hexanediisocyanate and terephthalic diisocyanate; And / or, the solvent includes one or more of acetone, chloroform, tetrahydrofuran, and dioxane; And / or, the catalyst includes one or more of organotin catalysts, amine catalysts and metal catalysts.

5. The polyfluorinated polyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 4, characterized in that, The cooling reaction conditions include: adding solvent when the temperature is reduced to 48-52°C.

6. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 4, characterized in that, The cooling reaction conditions include: cooling to 50°C and adding solvent.

7. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 4, characterized in that, The organotin catalysts include dibutyltin dilaurate or stannous octoate.

8. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 4, characterized in that, The amine catalyst includes diethylenetriamine or dimethylaminoethyl ether.

9. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 4, characterized in that, The metal catalyst includes potassium isooctanoate.

10. The polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 3, characterized in that, The protective atmosphere includes one of nitrogen, argon, or helium.

11. The low-dielectric ink for inkjet 3D printing based on polyfluorinated polyurethane acrylate as described in claim 3, characterized in that, The molar ratio of the diisocyanate monomer to the polyfluorinated diol is 1.10 to 1.50:1; And / or, the molar ratio of 2-hydroxyethyl acrylate to diisocyanate monomer is 0.30 to 0.69:1; And / or, taking polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate as a whole, the equivalence relationship between the total volume of solvent added during the cooling reaction and the total volume of solvent added after the cooling reaction and the total mass of polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate is (2.0~4.0ml):1g; And / or, taking the polyfluorinated diol, diisocyanate and 2-hydroxyethyl acrylate as a whole, the catalyst accounts for 0.8% to 2% of the total mass of the polyfluorinated diol, diisocyanate monomer and 2-hydroxyethyl acrylate; And / or, the number of repeating units of polyfluorinated diols and diisocyanates in the main chain of the polyfluorinated polyurethane acrylate prepolymer is 1 to 5.

12. The low-dielectric ink for inkjet 3D printing based on polyfluorinated polyurethane acrylate as described in claim 1, characterized in that, The diluting monomers include 4-acryloylmorpholine, tricyclic [5.2.1.0 2,6] sebacate diacrylate, tris(2-acryloyloxyethyl) isocyanurate and 1,10-bis(acryloyloxy)decane; The low-dielectric ink for inkjet 3D printing, composed of polyfluorinated polyurethane acrylate prepolymer (5wt%-15wt%), photoinitiator (1wt%-10wt%), 4-acryloylmorpholine (5-25wt%), tricyclic [5.2.1.0 2,6] sebacate diacrylate (5-25wt%), tri(2-acryloyloxyethyl) isocyanurate (48-51wt%), and 1,10-bis(acryloyloxy)decane (5-25wt%). And / or, the photoinitiator comprises one or more of 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, triarylhexafluorophosphate thioonium salt, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and ethyl 2,4,6-trimethylbenzoylphosphonate.

13. The polyfluorinated polyurethane acrylate low-dielectric ink for inkjet 3D printing according to claim 12, characterized in that, Tris(2-acryloyloxyethyl) isocyanurate accounts for 48 wt% of the total ink mass.

14. A method for preparing a polyfluorinated polyurethane acrylate low-dielectric ink for inkjet 3D printing as described in claim 1, characterized in that, Includes the following steps: The polyfluoropolyurethane acrylate prepolymer, diluent monomer, and photoinitiator were stirred and mixed under light-protected conditions, and then subjected to defoaming treatment to obtain a polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing.

15. A method for preparing a polyfluorinated polyurethane acrylate low-dielectric ink for inkjet 3D printing as described in claim 14, characterized in that, The bubble extraction process involves ultrasound and vacuuming.

16. A curing material, characterized in that, The curing material is prepared by inkjet printing using the polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing as described in any one of claims 1-13 or the polyfluoropolyurethane acrylate low-dielectric ink for inkjet 3D printing prepared by the method described in claim 14 or 15.

17. The curing material according to claim 16, characterized in that, The glass transition temperature T of the cured material g The temperature ranges from 160 to 230℃. And / or, the tensile strength of the cured material is 45-70 MPa, and the elongation at break is 5%-15%; And / or, the dielectric constant of the cured material is 2.40 to 2.90 at 20 GHz, and the dielectric loss is 0.010 to 0.020 at 20 GHz.

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