Siloxane benzocyclobutene prepolymer, high-temperature-resistant low-dielectric ink for solvent-free inkjet 3D printing, and preparation method and application thereof

Abstract

The application provides a siloxane benzocyclobutene prepolymer, a high-temperature-resistant low-dielectric ink for solvent-free inkjet 3D printing, and a preparation method and application thereof, relates to the technical field of high-performance inkjet 3D printing materials, and the siloxane benzocyclobutene / acrylate low-dielectric ink for solvent-free inkjet 3D printing is prepared by blending linear divinyl siloxane benzocyclobutene prepolymer and acrylate. After the printed ink is cured by light and heat, the ink has excellent dielectric properties, thermodynamic properties, mechanical properties and processing properties.

Description

Technical Field

[0001] This invention relates to the field of high-performance inkjet 3D printing materials technology, and in particular to a siloxane benzocyclobutene prepolymer, a solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink, its preparation method and application. Background Technology

[0002] In recent years, new electronic devices have placed new demands on the high-performance, high-heat-resistance, high-insulation, high-density, and high-precision fabrication of insulating materials. Compared to the high-cost and high-energy-consumption traditional vacuum lithography process, inkjet 3D printing technology has a significant competitive advantage in the manufacturing of microelectronic circuits and functional devices due to its high material utilization rate, customized design, high patterning accuracy, and low cost. Insulating ink is fundamental to the performance of printed electronic devices, and the development of various high-performance functional insulating ink materials has attracted widespread attention and has enormous potential.

[0003] Existing low-dielectric inks for inkjet 3D printing are mostly limited by inkjet printing equipment's constraints on ink viscosity and the curing shrinkage rate required for fine circuit structures. These inks are primarily composed of solvent-free acrylics, cyanate esters, and solvent-containing polyimides and polyarylether resins. The resulting photosensitive materials, after inkjet printing and UV curing, exhibit significant volume shrinkage, oxygen sensitivity, and inherent brittleness and poor heat resistance. This makes them unsuitable for use in communication devices such as circuit boards, often resulting in poor mechanical properties and thermal stability. They fail to meet the technical requirements of aerospace, microelectronics manufacturing, and other fields demanding high heat resistance, low dielectric constant, high mechanical strength, and high precision. Therefore, developing solvent-free inkjet 3D printing insulating inks with high heat resistance, low dielectric constant, high strength, and low curing shrinkage is crucial and directly impacts their practical application. Summary of the Invention

[0004] The purpose of this invention is to provide a siloxane benzocyclobutene prepolymer, a solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink, its preparation method, and its application. The solvent-free inkjet 3D printing siloxane benzocyclobutene / acrylate low-dielectric ink is prepared by blending linear divinylsiloxane benzocyclobutene prepolymer and acrylate. After printing, the ink, after photo / thermal curing, exhibits excellent dielectric properties, thermodynamic properties, mechanical properties, and processability.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a linear divinylsiloxane benzocyclobutene prepolymer, the structural formula of which is shown below:

[0007]

[0008] Wherein, R includes:

[0009]

[0010] One or more of the following;

[0011] n = 1-15; m = 1-15.

[0012] The present invention also provides a method for preparing the linear divinylsiloxane benzocyclobutene prepolymer as described above, comprising the following steps:

[0013] S1: Divinylsiloxane monomer, halobenzocyclobutene monomer, palladium catalyst, catalyst ligand, organic base, and organic solvent are added to a container and heated under reflux. After the reaction is completed, the mixture is cooled to obtain the reaction solution.

[0014] S2: Pour the reaction solution into a hydrochloric acid aqueous solution, stir, then add the extractant for extraction, and then filter to obtain the extract;

[0015] S3: The extract was washed and rotary evaporated to obtain a crude product. The crude product was then purified to obtain a linear divinylsiloxane benzocyclobutene prepolymer.

[0016] Furthermore, based on the above technical solution, in step S1, the reaction temperature is 80-110℃ and the reaction time is 24-36h;

[0017] And / or, the cooling is cooling to room temperature;

[0018] And / or, the container is treated to be anhydrous and oxygen-free and protected by nitrogen gas;

[0019] And / or, in step S2, the concentration of the hydrochloric acid aqueous solution is 1-1.5 mol / L;

[0020] And / or, the extractant includes one or more of dichloromethane, ethyl acetate, and diethyl ether;

[0021] And / or, in step S3, the washing includes: first washing the extract with deionized water, then washing with a 5wt% sodium carbonate aqueous solution, and finally washing with saturated saline solution.

[0022] And / or, the purification is performed by column chromatography; the eluent in the column chromatography is petroleum ether;

[0023] And / or, the linear divinylsiloxane benzocyclobutene prepolymer has a number-average molecular weight of 400-5000 g / mol;

[0024] And / or, the divinylsiloxane monomer comprises one of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, divinyl-terminated dimethylpolysiloxane, a diethylene-terminated dimethylsiloxane-diphenylsiloxane block copolymer, diethylene-terminated trifluorobutylmethylsiloxane, diethylene-terminated trifluorobutylmethylsiloxane-dimethylsiloxane copolymer, diethylene-terminated nonafluoropentylmethylsiloxane-dimethylsiloxane copolymer, diethylene-terminated diethylsiloxane-dimethylsiloxane copolymer, and diethylene-terminated ethylene-siloxane copolymer;

[0025] And / or, the halobenzocyclobutene includes 4-bromobenzocyclobutene or 4-chlorobenzocyclobutene;

[0026] And / or, the palladium catalyst comprises one or more of palladium acetate, palladium neopentanoate, palladium trifluoroacetate, palladium chloride, and palladium acetylacetonate;

[0027] And / or, the catalyst ligand is one or more of trimethylphenylphosphine, tribenzylphosphine, 1,1'-bis(diphenylphosphine)ferrocene, and tricyclohexylphosphine;

[0028] And / or, the organic base is one or more of triethylamine, potassium carbonate, sodium acetate, and cesium carbonate;

[0029] And / or, the organic solvent is a polar organic solvent, preferably, the organic solvent includes one or more of acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and water;

[0030] And / or, the molar ratio of the divinylsiloxane monomer to the halobenzocyclobutene monomer is 1:2-2.3;

[0031] And / or, the molar amount of the palladium catalyst is 4-5% of the molar amount of the divinylsiloxane monomer;

[0032] And / or, the molar amount of the catalyst ligand is 6-8% of the molar amount of the divinylsiloxane monomer;

[0033] And / or, the ratio of the amount of organic solvent added in step S1 to the total mass of the divinylsiloxane monomer and the halobenzocyclobutene monomer is 1 ml: (0.15-7) g.

[0034] The present invention also provides a solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink, comprising, by weight percentage, the following raw materials: 10wt%-20wt% of the linear divinylsiloxane benzocyclobutene prepolymer as described above or the linear divinylsiloxane benzocyclobutene prepolymer prepared by the method described above, 70wt%-80wt% of reactive diluent, and 1wt%-10wt% of photoinitiator.

[0035] Furthermore, based on the above technical solution, the viscosity of the solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink at 60°C is 20-70 cps, preferably 20-30 cps.

[0036] The present invention also provides a method for preparing the solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink as described above, comprising the following steps:

[0037] A solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink was obtained by stirring a linear divinylsiloxane benzocyclobutene prepolymer, an active diluent, and a photoinitiator at room temperature in the dark.

[0038] Furthermore, based on the above technical solution, the reactive diluent is an acrylate reactive diluent. Preferably, the reactive diluent includes one or more of the following: tripropylene glycol diacrylate, polyethylene glycol (200) diacrylate, 1,6-hexanediol diacrylate, tricyclo[5.2.1.02,6] sebacic acid diacrylate, 1,10-bis(acryloyloxy)decane, bisphenol A methacrylate diester, isobornyl acrylate, diether fluorene diacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, tricyclopentenyl acrylate, dicyclopentenyl acrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate.

[0039] And / or, the photoinitiator comprises one or more of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthiophenyl)-2-morpholino-1-propanone], 2-hydroxy-2-methyl-1-phenylpropanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, 2,2-dimethoxy-2-phenylacetophenone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, trimethylbenzoyldiphenylphosphine oxide, benzophenone, 2,4,6-trimethylbenzophenone, and 4-methylbenzophenone.

[0040] The present invention also provides the application of the solvent-free inkjet 3D printing high temperature resistant low dielectric ink prepared by the above-described method or the solvent-free inkjet 3D printing high temperature resistant low dielectric ink prepared by the above-described method in the preparation of inkjet 3D printed products. The ink is obtained by inkjet 3D printing, ultraviolet pre-curing and thermal curing in sequence.

[0041] Furthermore, based on the above technical solution, the product is selected from one of the following: electronic devices, electronic circuits, capacitors, antennas, sensors, and thin films.

[0042] Furthermore, based on the above technical solution, when the product is an inkjet 3D printed film,

[0043] The inkjet 3D printed film has a glass transition temperature (Tg) of 150-230℃, a tensile strength of 40-90MPa, an elongation at break of 5%-25%, a dielectric constant of 2.40-3.30 at 15GHz, a dielectric loss of 0.008-0.020 at 15GHz, an initial weight loss temperature of 150-220℃, and a 5% thermal weight loss temperature of 300-380℃.

[0044] And / or, the shrinkage rate of the inkjet 3D printed film is less than 5.1%;

[0045] And / or, the UV pre-curing wavelength is 355-405nm, preferably 380-405nm; the curing power is 500-5000mW, preferably 1500-3000mW;

[0046] The photocuring time is 20-100 seconds;

[0047] The ultraviolet energy density is 20 mw / cm² 2 -100 mw / cm 2 ;

[0048] And / or, the thermosetting includes sequentially performed first thermosetting, second thermosetting, third thermosetting, fourth thermosetting, fifth thermosetting, and sixth thermosetting; preferably,

[0049] The first thermosetting temperature is 80-100℃, and the holding time is 1-2 hours;

[0050] The second thermosetting temperature is 120-140℃, and the holding time is 1-2 hours;

[0051] The third thermosetting temperature is 150-160℃, and the holding time is 1-2 hours;

[0052] The fourth thermosetting temperature is 180-200℃, and the holding time is 1-2 hours;

[0053] The fifth thermosetting temperature is 200-230℃, and the holding time is 1-2 hours;

[0054] The sixth thermosetting temperature is 230-250℃, and the holding time is 2 hours;

[0055] The thermosetting is carried out in a vacuum, nitrogen, or argon atmosphere;

[0056] The temperatures for the first to sixth heat curing processes increase sequentially.

[0057] The present invention provides a linear divinylsiloxane benzocyclobutene prepolymer and its preparation method, a solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink and its preparation method and application, with the following beneficial effects:

[0058] Based on the requirements of inkjet 3D printing circuit board technology for material viscosity and curing shrinkage, this invention designs a solvent-free ink system for inkjet 3D printing based on a low-viscosity linear divinylsiloxane benzocyclobutene prepolymer and a low-shrinkage curing rate of benzocyclobutene. Simultaneously, to avoid sacrificing the excellent insulation and temperature resistance properties of benzocyclobutene itself, this invention employs a photothermal dual-curing strategy for high-performance ink design. By introducing acrylate diluents and photoinitiators with low viscosity, strong dilution properties, and high photosensitive activity into the ink system, pre-forming is achieved through inkjet 3D printing and UV curing. A tetrahydronaphthalene network structure is formed through the Diels-Alder reaction of benzocyclobutene and vinyl double bonds, ultimately resulting in inkjet 3D printed devices or films with high heat resistance, low dielectric constant, and high strength. This invention, through the design of an insulating ink for inkjet 3D printing using the above-mentioned linear divinylsiloxane benzocyclobutene prepolymer, obtains a photosensitive low-dielectric ink suitable for inkjet 3D printing with low viscosity, low curing shrinkage, and excellent high temperature resistance and low dielectric properties. It solves the key technical problems of poor heat resistance, poor insulation, low strength, and unstable printing of existing inkjet 3D printing low-dielectric materials.

[0059] The results of the examples show that the solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink provided by the present invention has a low viscosity (<30cps), and the inkjet 3D printing film obtained after photothermal dual curing has a high heat distortion temperature (180-220℃), low dielectric constant (frequency 15GHz: 2.4-3.3), low dielectric loss (frequency 15GHz: 0.008-0.019), high mechanical strength (42.1-87.7MPa), and low shrinkage rate (<5.1%). Attached Figure Description

[0060] 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.

[0061] Figure 1 The 1H NMR spectrum of the linear divinylsiloxane benzocyclobutene prepolymer 1 prepared in Example 1 of this invention;

[0062] Figure 2 The infrared spectra of the solvent-free inkjet 3D printing thin films with high temperature resistant and low dielectric ink prepared in Examples 4-8 of this invention are shown.

[0063] Figure 3 The tensile-displacement diagram shows the high-temperature resistant, low-dielectric ink film for solvent-free inkjet 3D printing prepared in Example 6 of this invention.

[0064] Figure 4 This is a dynamic thermomechanical analysis diagram of the solvent-free inkjet 3D printing film with high temperature resistant and low dielectric ink prepared in Example 4 of the present invention.

[0065] Figure 5 This is a thermal decomposition performance diagram of the high-temperature resistant, low-dielectric ink film for solvent-free inkjet 3D printing prepared in Example 1 of the present invention.

[0066] Figure 6 This is a dielectric property diagram of the high-temperature resistant, low-dielectric ink film for solvent-free inkjet 3D printing prepared in Example 6 of the present invention.

[0067] Figure 7 The rheological properties of the inkjet printing inks prepared in Examples 2-6 of this invention are shown at 60°C. Detailed Implementation

[0068] 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.

[0069] 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.

[0070] According to a first aspect of the present invention, a linear divinylsiloxane benzocyclobutene prepolymer is provided, having the following structural formula:

[0071] Wherein, R includes:

[0072]

[0073] One or more of the following;

[0074] n = 1-15; m = 1-15.

[0075] Specifically, starting from molecular structure design, this invention synthesizes a prepolymer with a low-polarity siloxane backbone and a high-rigidity and high-curing-degree vinylbenzocyclobutene. On the one hand, this can endow the prepolymer backbone with strong flexibility and low polarity, thereby improving its dielectric and mechanical properties; on the other hand, it can significantly increase the crosslinking density of the monomer and reduce dielectric loss.

[0076] A second aspect of the present invention provides a method for preparing the above-mentioned linear divinylsiloxane benzocyclobutene prepolymer, comprising the following steps:

[0077] S1: Divinylsiloxane monomer, halobenzocyclobutene monomer, palladium catalyst, catalyst ligand, organic base, and organic solvent are added to a container and heated under reflux. After the reaction is completed, the mixture is cooled to obtain the reaction solution.

[0078] S2: Pour the reaction solution into a hydrochloric acid aqueous solution, stir, then add the extractant for extraction, and then filter to obtain the extract;

[0079] S3: The extract was washed and rotary evaporated to obtain a crude product. The crude product was then purified to obtain a linear divinylsiloxane benzocyclobutene prepolymer.

[0080] Specifically, the linear divinylsiloxane benzocyclobutene prepolymer is obtained by a Heck coupling reaction between a divinylsiloxane monomer and a halobenzocyclobutene monomer (bromobenzocyclobutene monomer in formula (I) below), as shown in formula (I) below:

[0081]

[0082] The R group here is the same as the R group in the linear divinylsiloxane benzocyclobutene prepolymer.

[0083] During the reaction, in the presence of a strong base and a palladium catalyst, the strong base first reduces palladium from divalent to zero valence and binds to the ligand. Subsequently, it undergoes oxidative addition and inserts into the halogen atom of the halobenzocyclobutene between the halogen atom and the benzene ring. The empty palladium orbital in the halobenzocyclobutene after oxidative addition coordinates with the alkene and undergoes migration insertion. Then, the palladium catalyst on the double bond undergoes an elimination reaction with the hydrogen at the β-position to generate the product and palladium hydrogen. Subsequently, the palladium hydrogen undergoes reductive elimination to remove hydrogen bromide, thus returning to the catalytic starting state of the palladium catalyst.

[0084] As an optional embodiment of the present invention, in step S1, the reaction temperature is 80-110℃ (e.g., 80℃, 87℃, 91℃, 96℃ or 108℃, etc.), and the reaction time is 24-36h (e.g., 24h, 28h, 30h, 33h or 36h, etc.).

[0085] And / or, the cooling is cooling to room temperature;

[0086] And / or, the container is treated to be anhydrous and oxygen-free and protected by nitrogen gas.

[0087] As an optional embodiment of the present invention, in step S2, the concentration of the hydrochloric acid aqueous solution is 1-1.5 mol / L (e.g., 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L);

[0088] And / or, the extractant includes one or more of dichloromethane, ethyl acetate, and diethyl ether;

[0089] The purpose of the filtration is to remove insoluble substances from the reaction system, especially to remove palladium powder from the system.

[0090] And / or, in step S3, the washing includes: first washing the extract with deionized water, then washing with a 5wt% sodium carbonate aqueous solution, and finally washing with saturated saline solution.

[0091] Specifically, in step S3, the washing includes: first washing the extract with deionized water, then washing with a 5wt% sodium carbonate aqueous solution, and finally washing with saturated saline solution; preferably, the volume ratio of the deionized water, the 5wt% sodium carbonate aqueous solution, and the saturated saline solution is 1:1:1.

[0092] And / or, the purification is performed by column chromatography; the eluent in the column chromatography is petroleum ether;

[0093] And / or, the linear divinylsiloxane benzocyclobutene prepolymer has a number-average molecular weight of 400-5000 g / mol (e.g., 400 g / mol, 600 g / mol, 800 g / mol, 1000 g / mol, 2000 g / mol, 3000 g / mol, 4000 g / mol, or 5000 g / mol).

[0094] And / or, the divinylsiloxane monomer comprises one of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, divinyl-terminated dimethylpolysiloxane, a diethylene-terminated dimethylsiloxane-diphenylsiloxane block copolymer, diethylene-terminated trifluorobutylmethylsiloxane, diethylene-terminated trifluorobutylmethylsiloxane-dimethylsiloxane copolymer, diethylene-terminated nonafluoropentylmethylsiloxane-dimethylsiloxane copolymer, diethylene-terminated diethylsiloxane-dimethylsiloxane copolymer, and diethylene-terminated ethylene-siloxane copolymer;

[0095] And / or, the halobenzocyclobutene includes 4-bromobenzocyclobutene or 4-chlorobenzocyclobutene;

[0096] And / or, the palladium catalyst comprises one or more of palladium acetate, palladium neopentanoate, palladium trifluoroacetate, palladium chloride, and palladium acetylacetonate;

[0097] And / or, the catalyst ligand is one or more of trimethylphenylphosphine, tribenzylphosphine, 1,1'-bis(diphenylphosphine)ferrocene, and tricyclohexylphosphine;

[0098] And / or, the organic base is one or more of triethylamine, potassium carbonate, sodium acetate, and cesium carbonate;

[0099] And / or, the organic solvent is a polar organic solvent, preferably, the organic solvent includes one or more of acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and water;

[0100] And / or, the molar ratio of the divinylsiloxane monomer to the halobenzocyclobutene monomer is 1:2-2.3 (e.g., 1:2.1, 1:2.2, etc.);

[0101] And / or, the molar amount of the palladium catalyst is 4-5% (e.g., 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.8%, etc.) of the molar amount of the divinylsiloxane monomer;

[0102] And / or, the molar amount of the catalyst ligand is 6-8% (e.g., 6.5%, 7%, 7.5%, etc.) of the molar amount of the divinylsiloxane monomer;

[0103] And / or, the ratio of the amount of organic solvent added in step S1 to the total mass of the divinylsiloxane monomer and the halobenzocyclobutene monomer is 1 ml: (0.15-7) g (e.g., 1 ml: 1 g, 1 ml: 2 g, 1 ml: 3 g, 1 ml: 4 g, 1 ml: 5 g, 1 ml: 6 g, etc.).

[0104] According to a third aspect of the present invention, a solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink is provided, comprising the following raw materials: 10wt%-20wt% (e.g., 12wt%, 14wt%, 16wt%, 18wt%, etc.) of linear divinylsiloxane benzocyclobutene prepolymer as described above, 70wt%-80wt% (e.g., 72wt%, 74wt%, 76wt%, 78wt%, etc.) of reactive diluent, and 1wt%-10wt% (e.g., 2wt%, 4wt%, 6wt%, 8wt%, etc.) of photoinitiator.

[0105] Specifically, in this invention, the high-temperature resistant, low-dielectric ink for solvent-free inkjet 3D printing contains a linear divinylsiloxane benzocyclobutene prepolymer with an allyl benzocyclobutene structure, and an acrylate structure in the reactive diluent. The acrylate exhibits photosensitive activity and, during the photopolymerization 3D printing process, allows for dual curing, thereby improving the performance of the low-dielectric ink. This invention eliminates the need for additional oxygen scavengers; the same curing effect can be achieved by adding an initiator, thus avoiding the impact of oxygen scavengers on the dielectric properties of the low-dielectric ink.

[0106] As an optional embodiment of the present invention, the viscosity of the solvent-free inkjet 3D printing high temperature resistant low dielectric ink at 60°C is 20-70 cps (e.g., 30 cps, 40 cps, 50 cps, 60 cps, etc.), preferably 20-30 cps.

[0107] According to a fourth aspect of the present invention, a method for preparing the above-mentioned solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink is provided, comprising the following steps:

[0108] A solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink was obtained by stirring a linear divinylsiloxane benzocyclobutene prepolymer, an active diluent, and a photoinitiator at room temperature in the dark.

[0109] As an optional embodiment of the present invention, the reactive diluent is an acrylate reactive diluent. Preferably, the reactive diluent includes one or more of the following: tripropylene glycol diacrylate, polyethylene glycol (200) diacrylate, 1,6-hexanediol diacrylate, tricyclo[5.2.1.02,6] sebacic acid diacrylate, 1,10-bis(acryloyloxy)decane, bisphenol A methacrylate diester, isobornyl acrylate, diether fluorene diacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, tricyclopentenyl acrylate, dicyclopentenyl acrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate.

[0110] And / or, the photoinitiator comprises one or more of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthiophenyl)-2-morpholino-1-propanone], 2-hydroxy-2-methyl-1-phenylpropanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, 2,2-dimethoxy-2-phenylacetophenone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, trimethylbenzoyldiphenylphosphine oxide, benzophenone, 2,4,6-trimethylbenzophenone, and 4-methylbenzophenone.

[0111] According to a fifth aspect of the present invention, the application of the solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared by the method described above or the solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared by the method described above in the preparation of inkjet 3D printed products is provided, wherein the ink is sequentially subjected to inkjet 3D printing, ultraviolet pre-curing, and thermal curing to obtain the inkjet 3D printed product.

[0112] Specifically, the method for preparing inkjet 3D printed products includes the following steps:

[0113] Solvent-free inkjet 3D printing uses high-temperature resistant, low-dielectric ink for inkjet 3D printing and UV pre-curing to obtain a pre-formed device; then the pre-formed device is thermo-cured to obtain the inkjet 3D printed product.

[0114] As an optional embodiment of the present invention, the product is selected from one of electronic devices, electronic circuits, capacitors, antennas, sensors, and thin films.

[0115] In an optional embodiment of the present invention, when the product is an inkjet 3D printed film...

[0116] The inkjet 3D printed film has a glass transition temperature (Tg) of 150-230℃, a tensile strength of 40-90MPa, an elongation at break of 5%-25%, a dielectric constant of 2.40-3.30 at 15GHz, a dielectric loss of 0.008-0.020 at 15GHz, an initial weight loss temperature of 150-220℃, and a 5% thermal weight loss temperature of 300-380℃.

[0117] And / or, the shrinkage rate of the inkjet 3D printed film is less than 5.1%;

[0118] And / or, the UV pre-curing wavelength is 355-405nm, preferably 380-405nm; the curing power is 500-5000mW, preferably 1500-3000mW;

[0119] The photocuring time is 20-100s (e.g., 30s, 40s, 50s, 60s, 70s, 80s or 90s);

[0120] The ultraviolet energy density is 20 mw / cm² 2 -100 mw / cm 2 (For example, 30mw / cm) 2 40mw / cm 2 50mw / cm 2 60mw / cm 2 70mw / cm 2 80mw / cm 2 Or 90mw / cm 2 );

[0121] And / or, the thermosetting includes sequentially performed first thermosetting, second thermosetting, third thermosetting, fourth thermosetting, fifth thermosetting, and sixth thermosetting; preferably,

[0122] The first thermosetting temperature is 80-100℃ (e.g., 85℃, 90℃, 95℃, etc.), and the holding time is 1-2 hours;

[0123] The second heat curing temperature is 120-140℃ (e.g., 125℃, 130℃, 135℃, etc.), and the holding time is 1-2 hours;

[0124] The third thermosetting temperature is 150-160℃ (e.g., 155℃, 160℃, 165℃, etc.), and the holding time is 1-2 hours;

[0125] The fourth thermosetting temperature is 180-200℃ (e.g., 185℃, 190℃, 195℃, etc.), and the holding time is 1-2 hours;

[0126] The fifth thermosetting temperature is 200-230℃ (e.g., 210℃, 220℃, 225℃, etc.), and the holding time is 1-2 hours;

[0127] The sixth thermosetting temperature is 230-250℃ (e.g., 235℃, 240℃, 245℃, etc.), and the holding time is 2 hours;

[0128] The thermosetting is carried out in a vacuum, nitrogen, or argon atmosphere;

[0129] The temperatures for the first to sixth heat curing processes increase sequentially.

[0130] Specifically, the low-dielectric ink prepared by this invention can be used to prepare a cured film using a photo / thermal dual-curing system, realizing a dual curing system of free radical polymerization and Diels-Alder polymerization, thereby forming a polymer interpenetrating network (IPN). The polymer interpenetrating network (IPN) can significantly improve the toughness of the printed film through chain entanglement without changing the material strength.

[0131] The present invention will now be described in further detail with reference to specific preparation examples, embodiments, and comparative examples.

[0132] First, the following needs to be explained:

[0133] 1,1,3,3-Tetramethyl-1,3-divinyldisiloxane: CAS No. 2627-95-4, manufacturer: MACKLIN, catalog number: D830977;

[0134] Divinyl-terminated dimethyl polysiloxane: CAS No. 68083-19-2, manufacturer: MACKLIN, product number: V790515;

[0135] Diethylene-terminated dimethylsiloxane-diphenylsiloxane block copolymer: CAS No. 68951-96-2, manufacturer: MACKLIN, product number: P909961;

[0136] Diethylene-terminated trifluorobutylmethylsiloxane: prepared according to the literature with DOI number 10.1055 / s-0036-1588877;

[0137] Diethylene-terminated trifluorobutylmethylsiloxane dimethylsiloxane copolymer: CAS No. 68951-98-4, manufacturer: MACKLIN, product number: V934250;

[0138] Diethylene-terminated nonafluoropentylmethylsiloxane dimethylsiloxane copolymer: CAS No. 609768-44-7, manufacturer: Gelest, product number: FNV-3031;

[0139] Diethylene-terminated diethylsiloxane-dimethylsiloxane copolymer: CAS No. 26710-23-6, manufacturer: Gelest, product number: DCE-V7512;

[0140] Diethylene-terminated ethylene-siloxane copolymer: Manufacturer: Gelest, Product No.: EDV-2022.

[0141] Preparation Example 1

[0142] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0143]

[0144] 1,1,3,3-Tetramethyl-1,3-divinyldisiloxane (1.22 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), and acetonitrile (10 mL) were added to a three-necked flask that had been treated to be anhydrous and oxygen-free under a N2 atmosphere. The system temperature was raised to 82 °C and refluxed for 24 h, after which the temperature of the reaction system was lowered to room temperature.

[0145] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography.

[0146] Figure 1 The 1H NMR spectrum of the linear divinylsiloxane benzocyclobutene prepolymer obtained in this preparation example is shown. The proton signals at 7.24 ppm, 7.18 ppm, and 6.99–7.01 ppm are assigned to protons H5, 6, and 7 on the benzene ring. Meanwhile, the peaks with chemical shifts at 6.34–6.38 ppm and 6.92–6.96 ppm are assigned to hydrogen on the vinyl group. The peak with a chemical shift of 0.25 ppm is assigned to hydrogen (H1) on the silanyl group. More importantly, a characteristic proton signal of benzocyclobutene appears at 3.16 ppm (H2). All hydrogens can be effectively assigned, indicating that the product structure is consistent with the design.

[0147] Preparation Example 2

[0148] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0149]

[0150] Where n = 10 - 15;

[0151] Divinyl-terminated dimethylpolysiloxane (4.8 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), and DMF (10 mL) were added to a three-necked flask that had been treated to be anhydrous and oxygen-free under a N2 atmosphere. The system temperature was raised to 90 °C and refluxed for 24 h, after which the temperature of the reaction system was lowered to room temperature.

[0152] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0153] Preparation Example 3

[0154] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0155]

[0156] Where n = 10 - 15, m = 5 - 10;

[0157] Diethylene-terminated dimethylsiloxane-diphenylsiloxane block copolymer (57 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), DMF (10 mL), and deionized water (3 mL) were added to a three-necked flask under N2 atmosphere protection and treated to be anhydrous and oxygen-free. The system temperature was raised to 95 °C and refluxed for 24 h, and then the temperature of the reaction system was lowered to room temperature.

[0158] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0159] Preparation Example 4

[0160] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0161]

[0162] Where n = 10 - 15;

[0163] Diethylene-terminated trifluorobutylmethylsiloxane (36 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), DMF (10 mL), and deionized water (5 mL) were added to a three-necked flask under N2 atmosphere protection and treated to be anhydrous and oxygen-free. The system temperature was raised to 100 °C and refluxed for 24 h, and then the temperature of the reaction system was lowered to room temperature.

[0164] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0165] Preparation Example 5

[0166] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0167]

[0168] Where n = 10⁻¹⁵, m = 10⁻¹⁵;

[0169] Diethylene-terminated trifluorobutylmethylsiloxane dimethylsiloxane copolymer (42 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), DMF (10 mL), and deionized water (10 mL) were added to a three-necked flask under N2 atmosphere protection and treated to be anhydrous and oxygen-free. The system temperature was raised to 103 °C and refluxed for 24 h, and then the temperature of the reaction system was lowered to room temperature.

[0170] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0171] Preparation Example 6

[0172] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0173]

[0174] Where n = 5 - 10, m = 10 - 15;

[0175] Diethylene-terminated trifluorobutylmethylsiloxane dimethylsiloxane copolymer (36 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), and DMF (20 mL) were added to a three-necked flask under N2 atmosphere protection and treated to be anhydrous and oxygen-free. The system temperature was raised to 110 °C and refluxed for 24 h, and then the temperature of the reaction system was lowered to room temperature.

[0176] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0177] Preparation Example 7

[0178] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0179]

[0180] Where n = 5 - 10, m = 10 - 15;

[0181] Diethylene-terminated nonafluoropentylmethylsiloxane dimethylsiloxane copolymer (54 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), and DMAc (25 mL) were added to a three-necked flask under N2 atmosphere protection and treated to be anhydrous and oxygen-free. The system temperature was raised to 110 °C and refluxed for 24 h, and then the temperature of the reaction system was lowered to room temperature.

[0182] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0183] Preparation Example 8

[0184] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0185]

[0186] Where n = 5 - 10, m = 5 - 10;

[0187] Diethylene-terminated diethylsiloxane-dimethylsiloxane copolymer (60 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), DMF (10 mL), and DMAc (15 mL) were added to a three-necked flask under N2 atmosphere protection and treated to be anhydrous and oxygen-free. The system temperature was raised to 110 °C and refluxed for 24 h, and then the temperature of the reaction system was lowered to room temperature.

[0188] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0189] Preparation Example 9

[0190] The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer prepared in this preparation example is:

[0191]

[0192] Where n = 10 - 15, m = 5 - 10;

[0193] Diethylene-terminated ethylene-siloxane copolymer (13 g, 6 mmol), 4-bromobenzocyclobutene (2.44 g, 13 mmol), triethylamine (1.86 g, 18.3 mmol), trimethylphenylphosphine (0.1258 g, 0.4 mmol), palladium acetate (0.05875 g, 0.26 mmol), acetonitrile (10 mL), and DMF (15 mL) were added to a three-necked flask under N2 atmosphere protection and treated to be anhydrous and oxygen-free. The system temperature was raised to 97 °C and refluxed for 24 h, and then the temperature of the reaction system was lowered to room temperature.

[0194] The reaction product was precipitated in 10 ml of 1 mol / L dilute hydrochloric acid solution, followed by the addition of 50 ml of dichloromethane. The insoluble matter in the system was removed by filtration, and then washed twice with 100 ml of deionized water, 100 ml of 5 wt% sodium carbonate aqueous solution, and 100 ml of saturated brine. The solvent was evaporated by rotary evaporation to obtain the crude product, which was then purified by column chromatography to obtain the linear divinylsiloxane benzocyclobutene prepolymer.

[0195] Table 1 is a summary table of the amount of each reactant added in Preparation Examples 1-9:

[0196]

[0197]

[0198] It should be noted that the structural characterization test methods for the prepolymers synthesized in the preparation examples and the performance test methods for the products of Examples 1-9 given in Table 2 are as follows:

[0199] Nuclear magnetic resonance (NMR) testing was performed on a Bruker Vaian DLG400 spectrometer to characterize the structure of the synthesized prepolymer.

[0200] Dynamic mechanical thermal analysis (DMA) test conditions: performed on a TAQ800 instrument at a frequency of 1 Hz and a heating rate of 5 °C / min.

[0201] Tensile property test conditions: conducted on an AnInstron-5869 machine, with a load of 500 N, a strain rate of 2 mm / min, an effective tensile length of 20 mm, and a width of 6 mm.

[0202] Thermogravimetric analysis (TGA) conditions: performed on a Mettler TGA instrument, with a nitrogen flow rate of 50 mL / min and a heating rate of 20 °C / min.

[0203] Dielectric performance testing conditions: The test was conducted on a Keysight N5227B PNA microwave network analyzer at room temperature and a frequency of 15 GHz.

[0204] Shrinkage rate test method: The curing shrinkage rate of the ink is measured by density method. The ink density before curing is measured by volumetric flask, and the ink density after curing is measured by density balance.

[0205] Viscosity testing method: The viscosity of the ink formulation was measured using an ARX200 rheometer at 25°C for 10 seconds. -1 up to 100s -1 The tests were performed using the shear rate table. Subsequently, the viscosity was tested at 30°C to 100°C using a temperature-scanning rotating model at a shear rate of 1 s⁻¹.

[0206] Example 1

[0207] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of diether fluorene diacrylate, 20% by weight of dicyclopentenyl acrylate, 10% by weight of isobornyl acrylate, 15% by weight of the prepolymer from Preparation Example 1, and 5% by weight of the photoinitiator trimethylbenzoyl diphenylphosphine oxide for 5 hours.

[0208] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 20 cps.

[0209] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0210] The inkjet insulating ink prepared in Example 1 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0211] Example 2

[0212] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of tricyclo[5.2.1.02,6] sebacic acid diacrylate, 20% by weight of 1,6-hexanediol diacrylate, 10% by weight of tricyclopentenyl acrylate, 15% by weight of the prepolymer from Preparation Example 2, and 5% by weight of the photoinitiator 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone for 5 hours.

[0213] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 28 cps.

[0214] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0215] The inkjet insulating ink prepared in Example 2 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0216] Example 3

[0217] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of tripropylene glycol diacrylate, 20% by weight of 1,10-bis(acryloyloxy)decane, 10% by weight of isobornyl acrylate, 15% by weight of the prepolymer from Preparation Example 3, and 5% by weight of the photoinitiator 2,2-dimethoxy-2-phenylacetophenone for 5 hours.

[0218] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 64 cps.

[0219] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0220] The inkjet insulating ink prepared in Example 3 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0221] Example 4

[0222] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of bisphenol A methacrylate diester, 20% by weight of 1,10-bis(acryloyloxy)decane, 10% by weight of dicyclopentenyl acrylate, 15% by weight of the prepolymer from Preparation Example 4, and 5% by weight of the photoinitiator 1-hydroxycyclohexylphenyl ketone for 5 hours.

[0223] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 43 cps.

[0224] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0225] The inkjet insulating ink prepared in Example 4 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0226] Example 5

[0227] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of polyethylene glycol (200) diacrylate, 20% by weight of 1,6-hexanediol diacrylate, 10% by weight of dicyclopentenyl acrylate, 15% by weight of the prepolymer from Preparation Example 5, and 5% by weight of the photoinitiator 1-hydroxycyclohexylphenyl ketone for 5 hours.

[0228] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 54 cps.

[0229] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0230] The inkjet insulating ink prepared in Example 5 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0231] Example 6

[0232] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of pentaerythritol tetraacrylate, 20% by weight of bisphenol A methacrylate diester, 10% by weight of isobornyl acrylate, 15% by weight of the prepolymer from Preparation Example 6, and 5% by weight of the photoinitiator 1-hydroxycyclohexylphenyl ketone for 5 hours.

[0233] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 37 cps.

[0234] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0235] The inkjet insulating ink prepared in Example 6 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0236] Example 7

[0237] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of bisphenol A methacrylate diester, 20% by weight of polyethylene glycol (200) diacrylate, 10% by weight of 1,10-bis(acryloyloxy)decane, 15% by weight of the prepolymer from Preparation Example 7, and 5% by weight of the photoinitiator 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone for 5 hours.

[0238] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 58 cps.

[0239] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0240] The inkjet insulating ink prepared in Example 7 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0241] Example 8

[0242] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of tricyclo[5.2.1.02,6] sebacate diacrylate, 20% by weight of bisphenol A methacrylate diester, 10% by weight of tricyclopentenyl acrylate, 15% by weight of the prepolymer from Preparation Example 8, and 5% by weight of the photoinitiator 2-methyl-1-[4-(methylthiophenyl)-2-morpholino-1-propanone] for 5 hours.

[0243] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 67 cps.

[0244] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0245] The inkjet insulating ink prepared in Example 8 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0246] Example 9

[0247] A low-viscosity insulating ink suitable for inkjet 3D printing can be prepared by mechanically stirring and mixing 50% by weight of 1,10-bis(acryloyloxy)decane, 20% by weight of trimethylolpropane triacrylate, 10% by weight of pentaerythritol tetraacrylate, 15% by weight of the prepolymer from Preparation Example 9, and 5% by weight of the photoinitiator phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide for 5 hours.

[0248] The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared in this embodiment has a viscosity of 58 cps.

[0249] The prepared inkjet printing insulating ink was printed using a commercial inkjet 3D printer and pre-cured under ultraviolet light (365nm wavelength, 2000mW power) to produce test and display parts. Finally, the printed and photocured parts were placed in a vacuum oven for thermosetting treatment. After treatment at 80℃ for 1 hour, 120℃ for 1 hour, 160℃ for 1 hour, 180℃ for 1 hour, 220℃ for 2 hours, and 250℃ for 2 hours, a high-performance inkjet printed device with an interpenetrating photothermal dual cross-linked network structure was obtained.

[0250] The inkjet insulating ink prepared in Example 9 was printed into a thin film with 50 layers and a total thickness of 60 micrometers. Performance tests were performed on 3-5 film samples, and the performance data are shown in Table 2.

[0251] Performance testing of inkjet 3D printed films

[0252] The performance tests of the inkjet 3D printed films prepared in Examples 1-9 are listed in Table 2.

[0253] Table 2 Performance of inkjet 3D printed films prepared in Examples 1-9

[0254]

[0255]

[0256] Figure 2 The infrared spectra of the solvent-free inkjet 3D printing films prepared in Examples 4-8 of this invention are shown. It can be seen that the C=C ratio in the cured photosensitive resin is at 1632 cm⁻¹. -1 1408cm -1 stretching vibration peak and 810 cm -1 The bending vibration peak disappeared, while benzocyclobutene showed a peak at 986 cm⁻¹. -1 The characteristic peaks also disappeared. This indicates that benzocyclobutene in the system underwent a Diels-Alder reaction under the combined action of ultraviolet light and a photoinitiator. Simultaneously, the reactive diluent C=C also participated in the photocuring reaction and formed a cross-linked network.

[0257] Figure 3 This is a tensile-displacement diagram of the solvent-free inkjet 3D printing film prepared according to Example 6 of the present invention, using high-temperature resistant, low-dielectric ink. As can be seen from the diagram, the tensile test process was satisfactory.

[0258] Figure 4 This is a dynamic thermomechanical analysis diagram of the solvent-free inkjet 3D printing film with high-temperature resistant and low-dielectric ink prepared in Example 4 of the present invention. As can be seen from the diagram, the glass transition temperature of the film can reach as high as 190℃, exhibiting excellent heat resistance.

[0259] Figure 5 The figure shows the thermal decomposition performance of the thin film prepared in Example 1 of the present invention. As can be seen from the figure, the thermal decomposition temperature of the thin film is 340℃, which shows excellent thermal stability.

[0260] Figure 6 The figure shows the dielectric properties of the thin film prepared in Example 6 of this invention. The test was performed using an impedance analyzer. As can be seen from the figure, at a frequency of 1 GHz, the dielectric constant (Dk) of the thin film prepared in Example 6 is 2.46 and the dielectric loss (Df) is 0.009, which shows excellent insulation properties.

[0261] Figure 7 The rheological properties of the inkjet printing inks prepared in Examples 2-6 of this invention are shown in the diagram at 60°C. All inks meet the basic viscosity requirements for inkjet printing inks. The viscosity of Example 2 is the lowest, reaching 28 cps. It can also be seen that the ink is a Newtonian fluid, which can ensure the stability of the droplets during the printing process and exhibits excellent processability.

[0262] Comparative Example 1

[0263] In this comparative example, the solvent-free acrylic monomer in Example 1 was replaced with a solvent-containing polyimide (see the photosensitive polyimide prepared in DOI: https: / / doi.org / 10.1016 / j.cej.2023.146858). All other reactants and operating procedures were the same as in Example 1. The properties of the prepared ink are as follows:

[0264] Viscosity 4000cps, Tg: 220℃, T5% 360℃, tensile strength 60MPa, elongation at break 7%, dielectric constant 2.52, dielectric loss 0.009.

[0265] Compared with Example 1, this comparative example replaces the solvent-free acrylic monomer with a solvent-containing polyimide. Due to the extremely poor solubility and high viscosity of polyimide, the prepared ink cannot be processed by inkjet printing and can only be prepared by the scraping method.

[0266] 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 solvent-free inkjet 3D printing ink with high temperature resistance and low dielectric constant, characterized in that, By weight percentage, it includes the following raw materials: 10wt%-20wt% linear divinylsiloxane benzocyclobutene prepolymer, 70wt%-80wt% reactive diluent, and 1wt%-10wt% photoinitiator; The structural formula of the linear divinylsiloxane benzocyclobutene prepolymer is shown below: ; Wherein, R includes: One or more of the following; n=1-15; m=1-15.

2. The solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink according to claim 1, characterized in that, The method for preparing the linear divinylsiloxane benzocyclobutene prepolymer includes the following steps: S1: Divinylsiloxane monomer, halobenzocyclobutene monomer, palladium catalyst, catalyst ligand, organic base, and organic solvent are added to a container and heated under reflux. After the reaction is completed, the mixture is cooled to obtain the reaction solution. S2: Pour the reaction solution into a hydrochloric acid aqueous solution, stir, then add the extractant for extraction, and then filter to obtain the extract; S3: The extract was washed and rotary evaporated to obtain a crude product. The crude product was then purified to obtain a linear divinylsiloxane benzocyclobutene prepolymer.

3. The solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink according to claim 2, characterized in that, In step S1, the reaction temperature is 80-110 ℃ and the reaction time is 24-36 h; And / or, the cooling is cooling to room temperature; And / or, the container is treated to be anhydrous and oxygen-free and protected by nitrogen gas; And / or, in step S2, the concentration of the hydrochloric acid aqueous solution is 1-1.5 mol / L; And / or, the extractant includes one or more of dichloromethane, ethyl acetate, and diethyl ether; And / or, in step S3, the washing includes: first washing the extract with deionized water, then washing with a 5wt% sodium carbonate aqueous solution, and finally washing with saturated saline solution. And / or, the purification is performed by column chromatography; the eluent in the column chromatography is petroleum ether; And / or, the linear divinylsiloxane benzocyclobutene prepolymer has a number-average molecular weight of 400-5000 g / mol; And / or, the divinylsiloxane monomer comprises one of 1,1,3,3-tetramethyl-1,3-divinyldisiloxane, divinyl-terminated dimethylpolysiloxane, a diethylene-terminated dimethylsiloxane-diphenylsiloxane block copolymer, diethylene-terminated trifluorobutylmethylsiloxane, diethylene-terminated trifluorobutylmethylsiloxane-dimethylsiloxane copolymer, diethylene-terminated nonafluoropentylmethylsiloxane-dimethylsiloxane copolymer, diethylene-terminated diethylsiloxane-dimethylsiloxane copolymer, and diethylene-terminated ethylene-siloxane copolymer; And / or, the halobenzocyclobutene includes 4-bromobenzocyclobutene or 4-chlorobenzocyclobutene; And / or, the palladium catalyst comprises one or more of palladium acetate, palladium neopentanoate, palladium trifluoroacetate, palladium chloride, and palladium acetylacetonate; And / or, the catalyst ligand is one or more of trimethylphenylphosphine, tribenzylphosphine, 1,1'-bis(diphenylphosphine)ferrocene, and tricyclohexylphosphine; And / or, the organic base is one or more of triethylamine, potassium carbonate, sodium acetate, and cesium carbonate; And / or, the organic solvent is a polar organic solvent; And / or, the molar ratio of the divinylsiloxane monomer to the halobenzocyclobutene monomer is 1:2-2.3; And / or, the molar amount of the palladium catalyst is 4-5% of the molar amount of the divinylsiloxane monomer; And / or, the molar amount of the catalyst ligand is 6-8% of the molar amount of the divinylsiloxane monomer; And / or, the ratio of the amount of organic solvent added in step S1 to the total mass of the divinylsiloxane monomer and the halobenzocyclobutene monomer is 1 ml: (0.15-7) g.

4. The solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink according to claim 3, characterized in that, The organic solvent includes one or more of acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and water.

5. The solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink according to claim 1, characterized in that, The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink has a viscosity of 20-70 cps at 60°C.

6. The solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink according to claim 5, characterized in that, The solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink has a viscosity of 20-30 cps at 60°C.

7. A method for preparing a high-temperature resistant, low-dielectric ink for solvent-free inkjet 3D printing as described in any one of claims 1-6, characterized in that, Includes the following steps: A solvent-free inkjet 3D printing high-temperature resistant, low-dielectric ink was obtained by stirring a linear divinylsiloxane benzocyclobutene prepolymer, an active diluent, and a photoinitiator at room temperature in the dark.

8. The method for preparing high-temperature resistant, low-dielectric ink for solvent-free inkjet 3D printing according to claim 7, characterized in that, The reactive diluent is an acrylate-based reactive diluent; And / or, the photoinitiator comprises one or more of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-[4-(methylthiophenyl)-2-morpholino-1-propanone], 2-hydroxy-2-methyl-1-phenylpropanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, 2,2-dimethoxy-2-phenylacetophenone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, trimethylbenzoyldiphenylphosphine oxide, benzophenone, 2,4,6-trimethylbenzophenone, and 4-methylbenzophenone.

9. The method for preparing high-temperature resistant, low-dielectric ink for solvent-free inkjet 3D printing according to claim 8, characterized in that, The reactive diluent includes one or more of the following: tripropylene glycol diacrylate, polyethylene glycol (200) diacrylate, 1,6-hexanediol diacrylate, tricyclo[5.2.1.0 2,6] sebacate diacrylate, 1,10-bis(acryloyloxy)decane, bisphenol A methacrylate diester, isobornyl acrylate, diether fluorene diacrylate, tri(2-hydroxyethyl) isocyanurate triacrylate, tricyclopentenyl acrylate, dicyclopentenyl acrylate, trimethylolpropane triacrylate, and pentaerythritol tetraacrylate.

10. The application of a solvent-free inkjet 3D printing high-temperature resistant low-dielectric ink prepared by any one of the preparation methods of solvent-free inkjet 3D printing high-temperature resistant low-dielectric inks as described in any one of claims 1-6, or solvent-free inkjet 3D printing high-temperature resistant low-dielectric inks as described in any one of claims 7-9, in the preparation of inkjet 3D printed products, characterized in that, The ink is sequentially processed through inkjet 3D printing, UV pre-curing, and thermo-curing to obtain the inkjet 3D printed product.

11. The application according to claim 10, characterized in that, The product is selected from one of the following: electronic devices, electronic circuits, antennas, sensors, and thin films.

12. The application according to claim 11, characterized in that, When the product is an inkjet 3D printed film. The inkjet 3D printed film has a glass transition temperature (Tg) of 150-230℃, a tensile strength of 40-90MPa, an elongation at break of 5%-25%, a dielectric constant of 2.40-3.30 at 15GHz, a dielectric loss of 0.008-0.020 at 15GHz, an initial weight loss temperature of 150-220℃, and a 5% thermal weight loss temperature of 300-380℃. And / or, the shrinkage rate of the inkjet 3D printed film is less than 5.1%; And / or, the UV pre-curing wavelength is 355-405nm; the curing power is 500-5000mW; The photocuring time is 20-100 s; The ultraviolet energy density is 20 mw / cm² 2 -100 mw / cm 2 ; And / or, the thermosetting includes a first thermosetting, a second thermosetting, a third thermosetting, a fourth thermosetting, a fifth thermosetting, and a sixth thermosetting performed sequentially.

13. The application according to claim 12, characterized in that, The UV pre-curing wavelength is 380-405nm.

14. The application according to claim 12, characterized in that, The UV pre-curing power is 1500-3000mW.

15. The application according to claim 12, characterized in that, The first thermosetting temperature is 80-100℃, and the holding time is 1-2 hours; The second thermosetting temperature is 120-140℃, and the holding time is 1-2 hours; The third thermosetting temperature is 150-160℃, and the holding time is 1-2 hours; The fourth thermosetting temperature is 180-200℃, and the holding time is 1-2 hours; The fifth thermosetting temperature is 200-230℃, and the holding time is 1-2 hours; The sixth thermosetting temperature is 230-250℃, and the holding time is 2 hours; The thermosetting is carried out in a vacuum, nitrogen, or argon atmosphere; The temperatures for the first to sixth heat curing processes increase sequentially.

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