Cationic dual-curing ink as well as preparation method and application thereof

Abstract

The invention relates to the technical field of ink, in particular to cationic dual-curing ink and a preparation method thereof. The cationic dual-curing ink is prepared from the following components: 30wt%-50wt% of an epoxy cationic monomer, 20wt%-40wt% of a photo-initiation type siloxane free radical monomer, 2wt%-5wt% of a composite photo-initiation system, 1wt%-3wt% of a pH response type dispersing agent, 5wt%-10wt% of ethanol and 10wt%-20wt% of filler, the composite photo-initiation system comprises pentafluorophenyl modified triphenylsulfonium hexafluorophosphate and diphenyliodonium tetrafluoroborate, the pH response type dispersing agent is a quaternary ammonium salt-sulfonate block copolymer, and a cationic monomer and a free radical monomer of the cationic dual-curing ink are synchronously cured. The cationic monomer and the free radical monomer are fully combined and filled, and the free radical monomer effectively winds the cationic monomer in the thermosetting stage, so that the adhesive force of the ink is effectively improved, and the ink has the advantage of high curing efficiency and moisture resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of inks, and in particular to a cationic dual-curing ink and a preparation method and application thereof. Background Art

[0002] In modern printing technology, the curing process of ink is crucial, determining the mechanical properties and chemical resistance of printed products. Free radicals and cationic components play an important role in inks, especially in ultraviolet (UV) curing inks.

[0003] In actual production, there are significant differences in the reaction characteristics of free radical and cationic curing under ultraviolet (UV) light irradiation. Free radical curing, especially the polymerization of acrylate monomers, cures approximately three to five times faster than cationic curing (such as epoxy resin ring-opening polymerization). In the initial stage of UV irradiation, free radical curing quickly forms a cross-linked network. However, due to the extremely fast reaction rate, the movement of the molecular chain segments is restricted, resulting in the formation of a large number of large micropores in the network structure, with an initial pore size of approximately 80 nanometers.

[0004] In contrast, cationic curing initiates more slowly, typically only beginning gradually after the free radical network is formed. Due to the rigidity of the free radical network framework and the large steric hindrance between pores, the polymer chains generated by cationic curing have difficulty penetrating or diffusing into the micropores, resulting in low filling efficiency.

[0005] These micropores formed by free radical curing are large, reaching micrometer-scale gaps, with smooth pore walls and poor chemical compatibility with subsequent cationic polymers. Cationic polymers struggle to effectively bind to the free radical network through chemical bonding or physical entanglement, resulting in a weak interfacial layer after filling, which concentrates curing stress and exacerbates interfacial separation.

[0006] Furthermore, free radical curing initially forms a rigid skeleton, followed by volume shrinkage during cationic curing (for example, epoxy ring-opening polymerization shrinks by approximately 2%-5%), which can cause stress concentration within the coating. Under this stress, ineffectively filled micropores can easily become crack initiation points, further degrading the adhesion between the coating and the substrate (traditional systems only have adhesion levels of 2-3B).

[0007] Although the existing initiation system for curing inks uses a single cationic curing method, such as traditional iodonium salts to increase the cationic curing rate, the single cationic curing is extremely sensitive to environmental humidity. When the humidity exceeds 50%, the curing rate drops significantly by 40% to 60%. Dual curing systems have also been introduced. However, the existing dual curing systems have poor synchronization of free radical and cationic initiation by the photoinitiator because the spectral ranges of the photoinitiator's response to free radicals and cations do not overlap, resulting in a large difference in the curing rates of free radicals and cationics. That is, the synchronization of cationic ring-opening polymerization and free radical polymerization under ultraviolet (UV) light is poor. This asynchronous curing process brings two problems: first, the curing efficiency is low, and the complete curing time is as long as 10 to 15 minutes (under ultraviolet (UV) light intensity of 3000mW / cm 2 Secondly, prior curing with free radical polymerization strengthens the rigidity of the already formed free radical network framework, increasing steric hindrance between pores. This makes it difficult for the polymer chains generated by cationic curing to penetrate or diffuse into the micropores, resulting in reduced filling efficiency.

[0008] In addition, since traditional dispersants such as polyacrylates cannot dynamically adapt to changes in system pH after curing, the interface between fillers and resins is weakened, affecting the mechanical properties and durability of the ink. + Finally, the traditional anionic dispersant (such as polyacrylate) has a lower pH value after curing, and the electrostatic interaction with the resin matrix is ​​weakened, which causes the filler to fall off from the resin. There is an obvious filler-resin interface gap (gap width is about 5-10μm) in the cross section of the cured coating, which affects the performance of the ink. Using SEM observation, there is an obvious gap between the filler (such as silica) and the resin interface, such as: there is a filler with a width of 5 to 10μm in the resin gap.

[0009] It can be seen that the existing technology cannot solve the problems of ink adhesion, moisture sensitivity and curing efficiency at the same time, which limits the application of ink in high-precision printing and complex environments. Summary of the Invention

[0010] One of the purposes of the present invention is to avoid the shortcomings of the prior art and provide a cationic dual-cure ink. The cationic monomer and free radical monomer of the cationic dual-cure ink are cured simultaneously, so that the cationic monomer and the free radical monomer are fully combined and filled. During the thermosetting stage, the free radical monomer effectively entangles the cationic monomer, effectively improving the ink adhesion, curing efficiency and moisture resistance. The complete curing time of the ink is shortened to 3 to 5 minutes, which is faster than the traditional curing time of 10 to 15 minutes; the ink adhesion is improved from the traditional 2B to 3B to the highest level 5B, and the curing rate of the ink in an 80% humidity environment only decreases by 10 to 15%, while the traditional curing rate in an 80% humidity environment decreases by 40% to 60%.

[0011] The second object of the present invention is to avoid the shortcomings of the prior art and provide a method for preparing a cationic dual-cure ink, which can produce an ink with a fast curing speed, good adhesion and mechanical properties, and has the advantage of being easy to operate.

[0012] To achieve one of the above objectives, the present invention provides the following technical solutions:

[0013] Cationic dual-cure inks are available, including the following components:

[0014] Epoxy cationic monomer 30wt%~50wt%

[0015] Photoinitiated siloxane free radical monomer 20wt% to 40wt%

[0016] Composite photoinitiator system 2wt%~5wt%

[0017] pH responsive dispersant 1 wt% to 3 wt%

[0018] Ethanol 5wt%~10wt%

[0019] 10 wt% to 20 wt% of filler, the particle size of the filler is less than 500 nm, and the filler is nano-silicon dioxide or titanium dioxide,

[0020] The composite photoinitiator system includes a sulfonium salt and an iodonium salt, wherein the sulfonium salt and / or the iodonium salt is modified with a fluoroaryl group, wherein the fluoroaryl group is a pentafluorophenyl group or a trifluoromethylphenyl group, and the weight ratio of the sulfonium salt to the iodonium salt is 2 to 3:1.

[0021] The pH-responsive dispersant is a quaternary ammonium salt-sulfonate block copolymer, wherein the molar ratio of the quaternary ammonium salt to the sulfonate is 1:0.8 to 1:1.2.

[0022] In some embodiments, the epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene oxirane monomer, and epoxycyclohexane acrylate monomer.

[0023] In some embodiments, the photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

[0024] In some embodiments, the sulfonium salt is triphenylsulfonium hexafluorophosphate; and the iodonium salt is diphenyliodonium tetrafluoroborate.

[0025] The beneficial effects of the cationic dual-curing ink of the present invention are as follows:

[0026] (1) The cationic dual-curing ink of the present invention uses epoxy cationic monomers and photoinitiator-type siloxane free radical monomers as monomers, and the selected composite photoinitiator system includes sulfonium salts and iodonium salts, and the sulfonium salts and / or iodonium salts are modified with fluoroaryl groups. Since the composite photoinitiator system uses a composite photoinitiator system composed of sulfonium salts and iodonium salts modified with fluorinated aromatic groups, and introduces epoxy cationic monomers and photoinitiating siloxane free radical monomers of specific structures into the ink system, staged curing is achieved through an ultraviolet (UV) / heat dual triggering mechanism. Specifically: the sulfonium salt or iodonium salt in the composite photoinitiator system is compounded with a fluorinated aromatic group, and the fluorinated aromatic group introduces a fluorinated aromatic structure. The strong electron-withdrawing effect of the fluorine atom increases the quantum yield of the photoinitiator under 365nm ultraviolet (UV) light to 0.8 (the quantum yield of traditional iodonium salt is about 0.3), broadens the light absorption range of the photoinitiator, effectively improves the conversion rate of epoxy groups in cationic ring-opening polymerization and the group conversion rate in free radical polymerization, and under the same ultraviolet (UV) intensity, the complete curing time is shortened to 3 to 5 minutes, realizing efficient and synchronous dual curing of cationic monomers and free radical monomers, and controlling the shrinkage difference. Within 3%, it avoids the stress accumulation of "hardening first and then shrinking", and effectively improves the ink curing efficiency, so that even thick coatings can be uniformly filled. Furthermore: the composite photoinitiator system first initiates the simultaneous curing of the cationic epoxy cationic monomer and the free radical photoinitiator silicone free radical monomer through the action of ultraviolet light (UV), and then enters the thermal curing stage. Subsequently, the silicone free radical monomer cross-links to fill the remaining pores in the ultraviolet light (UV) curing stage, and realizes efficient filling of micropores through the diffusion and entanglement of flexible chain segments, while ultraviolet light (UV) preferentially triggers the rapid curing of cationic species, quickly forming a rigid three-dimensional network skeleton (initial modulus 1000MPa). At this time, the micropore size is small (<10nm) and evenly distributed, and the pore wall presents a "jagged" interlocking structure, overcoming the problem that the traditional free radical monomer is cured first, resulting in a large micropore size of 5-10μm interface gap, uneven distribution, and smooth pore wall. That is, during the thermal curing stage, the siloxane radical monomers cross-link to fill the remaining smaller cationic pores, and the siloxane radical monomers achieve efficient filling of the micropores through the diffusion and entanglement of the flexible chain segments, so that the epoxy cationic monomers and the siloxane radical monomers play a synergistic role, and realize the staged coordination of the cationic monomers forming the skeleton first and then the free radical filling, so that the rigid structure of the cationic skeleton provides support for the subsequent filling, avoiding the steric hindrance caused by the premature hardening of the free radical network. The initial micropore size is reduced by more than 80%, the filling path is more unobstructed, and the polymer diffusion distance is shortened. Therefore, the present invention realizes the coordinated optimization of "effective filling" by regulating the curing sequence and the micropore size. The small-sized micropores reduce physical barriers, and the flexible siloxane segments can achieve efficient filling by entanglement and diffusion; the interlocking structure enhances the cohesive strength of the coating, and the cross-grid adhesion is improved from the traditional 2-3B to 5B (the highest level).Through a phased, synergistic mechanism of "cationic skeleton construction and free radical micropore filling," the unfavorable prior formation of large micropores in the traditional system is transformed into a controllable prior formation of small-sized skeleton pores. Subsequently, the flexible siloxane chains are used to efficiently fill the micropores and strengthen the interface, ultimately breaking through the bottlenecks of existing technologies in adhesion and curing efficiency. Furthermore, the fluorinated aryl structure overcomes the humidity sensitivity limitation of cationic curing, broadening the application range of inks.

[0027] (2) The cationic dual-curing ink of the present invention, the quaternary ammonium salt-sulfonate block copolymer is a zwitterionic block copolymer dispersant containing a tertiary amine group. The dynamic charge conversion mechanism of the tertiary amine group and the sulfonic acid group in its molecular structure realizes the strengthening of the interfacial effect between the dispersion stage and the curing stage, breaking through the technical bottleneck of the traditional dispersant "effective dispersion-ineffective curing". It is a domestic first. In the preparation stage (pH = 8 to 9), it exhibits anionic characteristics to ensure uniform dispersion of the filler; during curing, the pH drops below 6.5, and the quaternary ammonium salt-sulfonate block copolymer dispersant turns to cationic characteristics, which can strengthen the interface bonding between the filler and the resin, so that it turns to cationic characteristics during curing, and strengthens the interface bonding between the filler (such as silica) and the resin through electrostatic action, reducing stress concentration at the pore boundary. By using the pH-responsive dispersant of the present invention, a strong bond is formed, and the interface strength is increased by 30%. Therefore, the use of the quaternary ammonium salt-sulfonate block copolymer dispersant exhibits anionic characteristics to ensure dispersibility in the ink preparation stage at pH = 8 to 9, and releases H with the cationic initiator during curing. + As the pH decreases, the quaternary ammonium salt-sulfonate block copolymer dispersant becomes cationic, promoting interfacial bonding between the filler and the resin. The molecular structure of this quaternary ammonium salt-sulfonate block copolymer dispersant, with its pH response threshold at pH 6.5, addresses the post-curing interface weakening issue experienced by conventional dispersants.

[0028] To achieve the second of the above objectives, the present invention provides the following technical solutions:

[0029] A method for preparing the above-mentioned cationic dual-cure ink is provided, comprising the following steps:

[0030] Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained;

[0031] Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer;

[0032] The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

[0033] In some embodiments, the sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2 mm to 0.4 mm, and the rotation speed of the sand mill is 1000 rpm to 2000 rpm.

[0034] In some embodiments, after the mixed material is dispersed by the sand mill, the filler particle size distribution is less than 500 nm.

[0035] In some embodiments, ultrasound is used to disperse the composite photoinitiator system in the solvent for a dispersion time of 8 min to 15 min.

[0036] In some embodiments, during vacuum degassing, the vacuum degree is -0.1 MPa to -0.5 MPa, and the vacuum degassing time is 20 min to 40 min.

[0037] The preparation method of a cationic dual-curing ink of the present invention has the following beneficial effects:

[0038] The preparation method of the cationic dual-curing ink of the present invention is easy to operate and suitable for large-scale production and application.

[0039] To achieve the third of the above objectives, the present invention provides the following technical solutions:

[0040] Provided is an application of the above-mentioned cationic dual-cure ink, comprising the following steps: printing the ink on a substrate, first triggering curing with ultraviolet light, the ultraviolet light treatment time being 0.1 min to 2 min, so that the ink forms a cationic skeleton with a modulus ≥1000 MPa;

[0041] Then enter the heat curing stage, the heat curing treatment time is 2min to 5min, so that the siloxane free radical monomers in the ink fill the gaps in the micropores in the cationic skeleton to form an interlocking structure, so that the size of the micropores in the cationic skeleton is less than 10nm. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is an SEM image of the interlocking structure formed at the coating-substrate interface. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention will be described in more detail below. Although preferred embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to make the present invention more thorough and complete and to fully convey the scope of the present invention to those skilled in the art.

[0044] Example 1

[0045] The cationic dual-curing ink disclosed in this embodiment includes the following components:

[0046] 30 wt % of an epoxy cationic monomer, wherein the epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene ethylene oxide monomer, and epoxycyclohexane acrylate monomer.

[0047] 28 wt % of a photoinitiated siloxane free radical monomer, wherein the photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

[0048] 4wt% of a composite photoinitiator system, the composite photoinitiator system comprising a sulfonium salt and an iodonium salt, the sulfonium salt and / or the iodonium salt being modified with a fluoroaryl group, the fluoroaryl group being a pentafluorophenyl group or a trifluoromethylphenyl group, the weight ratio of the sulfonium salt to the iodonium salt being 1:1, the sulfonium salt being triphenylsulfonium hexafluorophosphate; and the iodonium salt being diphenyliodonium tetrafluoroborate.

[0049] Dispersant 3wt%

[0050] Ethanol 10wt%

[0051] The filler is 20 wt %, and the filler is nano silicon dioxide or titanium dioxide. The filler can also be other fillers, and the particle size range of the filler is less than 500 nm.

[0052] The characteristics of the above-mentioned cationic dual-curing ink are:

[0053] For the first time, the above-mentioned specific structured epoxy cationic monomer and photoinitiated siloxane free radical monomer are introduced into the ink system, which facilitates the subsequent staged curing of the ink through the ultraviolet (UV) / heat dual triggering mechanism.

[0054] The composite photoinitiator system is combined with a sulfonium salt / iodonium salt, and the sulfonium salt / iodonium salt is modified with a fluorinated aromatic group. On the one hand, the strong electron-withdrawing effect of the fluorine atom increases the quantum yield of the photoinitiator under 365nm ultraviolet (UV) light to 0.8 (the quantum yield of traditional iodonium salt is about 0.3), and simultaneously triggers cationic ring-opening polymerization (epoxy group conversion rate >95%) and free radical polymerization (acrylate group conversion rate >98%), shortening the complete curing time to 3-5 minutes (ultraviolet (UV) intensity 3000mW / cm 2), therefore, a sulfonium salt / iodonium salt composite initiator modified with a fluorinated aromatic structure was introduced to improve the photoinitiation efficiency (quantum yield 0.8 vs. traditional 0.3) through the electron-withdrawing effect of fluorine atoms, and to achieve nanosecond synchronous triggering of dual-curing reactions. This photochemical activity regulation technology has not been reported in the field of inks. That is, under ultraviolet light (UV) irradiation, cationic ring-opening polymerization and free radical polymerization are triggered synchronously, and the curing efficiency is improved compared with the traditional single system. Specifically, in the cationic curing stage (0-2 minutes), a rigid three-dimensional network skeleton (initial modulus of 1000MPa) is quickly formed by epoxy cationic monomers, and then in the free radical curing stage (2-5 minutes), the siloxane monomers fill the micropores by cross-linking (the pore size is reduced from 80nm to less than 10nm). Scanning electron microscopy observations show that Figure 1 The coating-substrate interface forms a jagged, interlocking structure, improving adhesion by 2-3 levels (from 2-3B to 5B) compared to traditional dual-cure inks. This composite photoinitiator system, a dual-trigger UV / heat system, achieves over 90% cure within 5 minutes, with deeper curing results superior to single-cure systems. Under UV irradiation, cationic and free radical monomer reactions are simultaneously initiated (with a time difference of less than 100ms), increasing curing efficiency by more than three times.

[0055] On the other hand, since the sulfonium salt / iodonium salt is modified with a fluorinated aromatic group, the cationic curing rate only decreases by 10% to 15% in an environment with 80% humidity (the traditional system decreases by 40% to 60%), which effectively improves the curing efficiency of the cationic monomer.

[0056] To further illustrate how to prepare a cationic dual-cure ink, this embodiment also discloses a method for preparing a cationic dual-cure ink, which is characterized by comprising the following steps:

[0057] Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained;

[0058] The above steps yield a homogeneous first prepolymer, which is the basic material in the ink preparation process.

[0059] Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer;

[0060] Specifically, fillers and dispersants are added to the first prepolymer and mixed evenly. The resulting mixture is then dispersed in a sand mill to ensure uniform distribution of the fillers and dispersants. The resulting second prepolymer, an intermediate product in the ink preparation process, is obtained after the sand milling process.

[0061] The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

[0062] Specifically, the composite photoinitiator system is added to ethanol to uniformly disperse it. The dispersed composite photoinitiator system is then added to the second prepolymer and mixing continues. Finally, a vacuum degassing process is performed to remove bubbles generated during the mixing process to obtain the finished ink.

[0063] In this embodiment, the sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2 mm to 0.4 mm, and the rotation speed of the sand mill is 1000 rpm to 2000 rpm.

[0064] The diameter of the zirconium beads and the rotation speed of the sand mill can be adjusted according to production needs.

[0065] In this embodiment, after the mixed material is dispersed by the sand mill, the filler particle size distribution is less than 500 nm (D90).

[0066] In this embodiment, ultrasound is used to disperse the composite photoinitiator system in the solvent, and the dispersion time is 8 minutes to 15 minutes.

[0067] The dispersion time can be adjusted according to actual needs.

[0068] In this embodiment, during vacuum degassing, the vacuum degree is -0.1 MPa to -0.5 MPa, and the vacuum degassing time is 20 min to 40 min.

[0069] The vacuum treatment conditions can be adjusted according to actual needs.

[0070] Example 2

[0071] The cationic dual-curing ink disclosed in this embodiment includes the following components:

[0072] 50 wt % of epoxy cationic monomer, wherein the epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene ethylene oxide monomer, and epoxycyclohexane acrylate monomer.

[0073] 20 wt % of a photoinitiated siloxane free radical monomer, wherein the photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

[0074] 2wt% of a composite photoinitiator system, wherein the composite photoinitiator system includes a sulfonium salt and an iodonium salt, the sulfonium salt and / or the iodonium salt being modified with a fluorinated aromatic group, the weight ratio of the sulfonium salt to the iodonium salt being 2:1, the sulfonium salt being triphenylsulfonium hexafluorophosphate; and the iodonium salt being diphenyliodonium tetrafluoroborate.

[0075] The mechanism of action of the above composite photoinitiator system is as follows:

[0076] In the sulfonium / iodonium salt modified with a fluoroaryl group, the strong electron-withdrawing effect of the fluorine atom reduces the highest occupied molecular orbital (HOMO) energy level by approximately 0.8 eV, promoting the efficiency of photoexcited state charge separation and increasing the quantum yield to 0.8 (compared to approximately 0.3 for conventional iodonium salts). In particular, when the fluoroaryl group is a trifluoromethylphenyl group, the molar absorption coefficient at 365 nm reaches 5200 L·mol-1·cm -1 , which is about 3 times higher than that of the unmodified system.

[0077] Dispersant 1wt%

[0078] Ethanol 5wt%

[0079] The filler is 10%, and the filler is nano silicon dioxide, and the filler can also be other fillers.

[0080] The characteristics of the above-mentioned cationic dual-curing ink are:

[0081] For the first time, the above-mentioned specific structured epoxy cationic monomer and photoinitiated siloxane free radical monomer are introduced into the ink system, which facilitates the subsequent staged curing of the ink through the ultraviolet (UV) / heat dual triggering mechanism.

[0082] On the other hand, since the sulfonium salt / iodonium salt is modified with a fluorinated aromatic group, the cationic curing rate only decreases by 10%-15% under an 80% humidity environment (the traditional system decreases by 40%-60%), which effectively improves the curing efficiency of the cationic monomer.

[0083] To further illustrate how to prepare a cationic dual-cure ink, this embodiment also discloses a method for preparing a cationic dual-cure ink, which is characterized by comprising the following steps:

[0084] Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained;

[0085] The above steps yield a homogeneous first prepolymer, which is the basic material in the ink preparation process.

[0086] Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer;

[0087] Specifically, fillers and dispersants are added to the first prepolymer and mixed evenly. The resulting mixture is then dispersed in a sand mill to ensure uniform distribution of the fillers and dispersants. The resulting second prepolymer, an intermediate product in the ink preparation process, is obtained after the sand milling process.

[0088] The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

[0089] Specifically, the composite photoinitiator system is added to ethanol to uniformly disperse it. The dispersed composite photoinitiator system is then added to the second prepolymer and mixing continues. Finally, a vacuum degassing process is performed to remove bubbles generated during the mixing process to obtain the finished ink.

[0090] In this embodiment, the sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2 mm to 0.4 mm, and the rotation speed of the sand mill is 1000 rpm to 2000 rpm.

[0091] The diameter of the zirconium beads and the rotation speed of the sand mill can be adjusted according to production needs.

[0092] In this embodiment, after the mixed material is dispersed by the sand mill, the filler particle size distribution is less than 500 nm (D90).

[0093] In this embodiment, ultrasound is used to disperse the composite photoinitiator system in the solvent, and the dispersion time is 8 minutes to 15 minutes.

[0094] The dispersion time can be adjusted according to actual needs.

[0095] In this embodiment, during vacuum degassing, the vacuum degree is -0.1 MPa to -0.5 MPa, and the vacuum degassing time is 20 min to 40 min.

[0096] The vacuum treatment conditions can be adjusted according to actual needs.

[0097] Example 3

[0098] The cationic dual-curing ink disclosed in this embodiment includes the following components:

[0099] 35 wt % of an epoxy cationic monomer, wherein the epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene ethylene oxide monomer, and epoxycyclohexane acrylate monomer.

[0100] 28 wt % of a photoinitiated siloxane free radical monomer, wherein the photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

[0101] 4wt% of a composite photoinitiator system, wherein the composite photoinitiator system includes a sulfonium salt and an iodonium salt, the sulfonium salt and / or the iodonium salt being modified with a fluorinated aromatic group, the weight ratio of the sulfonium salt to the iodonium salt being 3:1, the sulfonium salt being triphenylsulfonium hexafluorophosphate; and the iodonium salt being diphenyliodonium tetrafluoroborate.

[0102] Dispersant 2wt%

[0103] Ethanol 9wt%

[0104] The filler is 15 wt %, and the filler is nano silicon dioxide, and the filler can also be other fillers.

[0105] The characteristics of the above-mentioned cationic dual-curing ink are:

[0106] For the first time, the above-mentioned specific structured epoxy cationic monomer and photoinitiated siloxane free radical monomer are introduced into the ink system, which facilitates the subsequent staged curing of the ink through the ultraviolet (UV) / heat dual triggering mechanism.

[0107] On the other hand, since the sulfonium salt / iodonium salt is modified with a fluorinated aromatic group, the cationic curing rate only decreases by 10% to 15% in an environment with 80% humidity (the traditional system decreases by 40% to 60%), which effectively improves the curing efficiency of the cationic monomer.

[0108] To further illustrate how to prepare a cationic dual-cure ink, this embodiment also discloses a method for preparing a cationic dual-cure ink, which is characterized by comprising the following steps:

[0109] Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained;

[0110] The above steps yield a homogeneous first prepolymer, which is the basic material in the ink preparation process.

[0111] Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer;

[0112] Specifically, fillers and dispersants are added to the first prepolymer and mixed evenly. The resulting mixture is then dispersed in a sand mill to ensure uniform distribution of the fillers and dispersants. The resulting second prepolymer, an intermediate product in the ink preparation process, is obtained after the sand milling process.

[0113] The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

[0114] Specifically, the composite photoinitiator system is added to ethanol to uniformly disperse it. The dispersed composite photoinitiator system is then added to the second prepolymer and mixing continues. Finally, a vacuum degassing process is performed to remove bubbles generated during the mixing process to obtain the finished ink.

[0115] In this embodiment, the sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2 mm to 0.4 mm, and the rotation speed of the sand mill is 1000 rpm to 2000 rpm.

[0116] The diameter of the zirconium beads and the rotation speed of the sand mill can be adjusted according to production needs.

[0117] In this embodiment, after the mixed material is dispersed by the sand mill, the filler particle size distribution is less than 500 nm (D90).

[0118] In this embodiment, ultrasound is used to disperse the composite photoinitiator system in the solvent, and the dispersion time is 8 minutes to 15 minutes.

[0119] The dispersion time can be adjusted according to actual needs.

[0120] In this embodiment, during vacuum degassing, the vacuum degree is -0.1 MPa to -0.5 MPa, and the vacuum degassing time is 20 min to 40 min.

[0121] The vacuum treatment conditions can be adjusted according to actual needs.

[0122] Example 4

[0123] The cationic dual-curing ink disclosed in this embodiment includes the following components:

[0124] 50 wt % of epoxy cationic monomer, wherein the epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene ethylene oxide monomer, and epoxycyclohexane acrylate monomer.

[0125] 20 wt % of a photoinitiated siloxane free radical monomer, wherein the photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

[0126] A composite photoinitiator system comprises 3 wt % of a sulfonium salt and an iodonium salt, wherein the weight ratio of the sulfonium salt to the iodonium salt is 2.5:1, and the weight ratio of the sulfonium salt to the iodonium salt can be adjusted according to actual conditions. The sulfonium salt and / or the iodonium salt is modified with a fluorinated aromatic group, the sulfonium salt is triphenylsulfonium hexafluorophosphate, and the iodonium salt is diphenyliodonium tetrafluoroborate.

[0127] Dispersant 1wt%

[0128] Ethanol 5wt%

[0129] The filler is 10%, and the filler is nano silicon dioxide, and the filler can also be other fillers.

[0130] The characteristics of the above-mentioned cationic dual-curing ink are:

[0131] For the first time, the above-mentioned specific structured epoxy cationic monomer and photoinitiated siloxane free radical monomer are introduced into the ink system, which facilitates the subsequent staged curing of the ink through the ultraviolet (UV) / heat dual triggering mechanism.

[0132] On the other hand, since the sulfonium salt / iodonium salt is modified with a fluorinated aromatic group, the cationic curing rate only decreases by 10% to 15% under an 80% humidity environment (the traditional system decreases by 40% to 60%), which effectively improves the curing efficiency of the cationic monomer.

[0133] To further illustrate how to prepare a cationic dual-cure ink, this embodiment also discloses a method for preparing a cationic dual-cure ink, which is characterized by comprising the following steps:

[0134] Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained;

[0135] The above steps yield a homogeneous first prepolymer, which is the basic material in the ink preparation process.

[0136] Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer;

[0137] Specifically, fillers and dispersants are added to the first prepolymer and mixed evenly. The resulting mixture is then dispersed in a sand mill to ensure uniform distribution of the fillers and dispersants. The resulting second prepolymer, an intermediate product in the ink preparation process, is obtained after the sand milling process.

[0138] The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

[0139] Specifically, the composite photoinitiator system is added to ethanol to uniformly disperse it. The dispersed composite photoinitiator system is then added to the second prepolymer and mixing continues. Finally, a vacuum degassing process is performed to remove bubbles generated during the mixing process to obtain the finished ink.

[0140] In this embodiment, the sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2 mm to 0.4 mm, and the rotation speed of the sand mill is 1000 rpm to 2000 rpm.

[0141] The diameter of the zirconium beads and the rotation speed of the sand mill can be adjusted according to production needs.

[0142] In this embodiment, after the mixed material is dispersed by the sand mill, the filler particle size distribution is less than 500 nm (D90).

[0143] In this embodiment, ultrasound is used to disperse the composite photoinitiator system in the solvent, and the dispersion time is 8 minutes to 15 minutes.

[0144] The dispersion time can be adjusted according to actual needs.

[0145] In this embodiment, during vacuum degassing, the vacuum degree is -0.1 MPa to -0.5 MPa, and the vacuum degassing time is 20 min to 40 min.

[0146] The vacuum treatment conditions can be adjusted according to actual needs.

[0147] Example 5

[0148] The cationic dual-curing ink disclosed in this embodiment includes the following components:

[0149] 30 wt % of an epoxy cationic monomer, wherein the epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene ethylene oxide monomer, and epoxycyclohexane acrylate monomer.

[0150] 40 wt % of a photoinitiated siloxane free radical monomer, wherein the photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

[0151] 5wt% of a composite photoinitiator system, wherein the composite photoinitiator system includes a sulfonium salt and an iodonium salt, wherein the sulfonium salt and / or the iodonium salt is modified with a fluorinated aromatic group, and the weight ratio of the sulfonium salt to the iodonium salt is 2 to 3:1, wherein the sulfonium salt is triphenylsulfonium hexafluorophosphate; and the iodonium salt is diphenyliodonium tetrafluoroborate.

[0152] Dispersant 3wt%

[0153] Ethanol 10wt%

[0154] The filler is 10 wt %, and the filler is nano silicon dioxide, and the filler can also be other fillers.

[0155] The characteristics of the above-mentioned cationic dual-curing ink are:

[0156] For the first time, the above-mentioned specific structured epoxy cationic monomer and photoinitiated siloxane free radical monomer are introduced into the ink system, which facilitates the subsequent staged curing of the ink through the ultraviolet (UV) / heat dual triggering mechanism.

[0157] On the other hand, since the sulfonium salt / iodonium salt is modified with a fluorinated aromatic group, the cationic curing rate only decreases by 10% to 15% under an 80% humidity environment (the traditional system decreases by 40% to 60%), which effectively improves the curing efficiency of the cationic monomer.

[0158] To further illustrate how to prepare a cationic dual-cure ink, this embodiment also discloses a method for preparing a cationic dual-cure ink, which is characterized by comprising the following steps:

[0159] Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained;

[0160] The above steps yield a homogeneous first prepolymer, which is the basic material in the ink preparation process.

[0161] Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer;

[0162] Specifically, fillers and dispersants are added to the first prepolymer and mixed evenly. The resulting mixture is then dispersed in a sand mill to ensure uniform distribution of the fillers and dispersants. The resulting second prepolymer, an intermediate product in the ink preparation process, is obtained after the sand milling process.

[0163] The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

[0164] Specifically, the composite photoinitiator system is added to ethanol to uniformly disperse it. The dispersed composite photoinitiator system is then added to the second prepolymer and mixing continues. Finally, a vacuum degassing process is performed to remove bubbles generated during the mixing process to obtain the finished ink.

[0165] In this embodiment, the sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2 mm to 0.4 mm, and the rotation speed of the sand mill is 1000 rpm to 2000 rpm.

[0166] The diameter of the zirconium beads and the rotation speed of the sand mill can be adjusted according to production needs.

[0167] In this embodiment, after the mixed material is dispersed by the sand mill, the filler particle size distribution is less than 500 nm (D90).

[0168] In this embodiment, ultrasound is used to disperse the composite photoinitiator system in the solvent, and the dispersion time is 8 minutes to 15 minutes.

[0169] The dispersion time can be adjusted according to actual needs.

[0170] In this embodiment, during vacuum degassing, the vacuum degree is -0.1 MPa to -0.5 MPa, and the vacuum degassing time is 20 min to 40 min.

[0171] The vacuum treatment conditions can be adjusted according to actual needs.

[0172] Example 6

[0173] The cationic dual-curing ink disclosed in this embodiment includes the following components:

[0174] 45 wt % of an epoxy cationic monomer, wherein the epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene ethylene oxide monomer, and epoxycyclohexane acrylate monomer.

[0175] 30 wt % of a photoinitiated siloxane free radical monomer, wherein the photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

[0176] 3wt% of a composite photoinitiator system, wherein the composite photoinitiator system includes a sulfonium salt and an iodonium salt, wherein the sulfonium salt and / or the iodonium salt is modified with a fluorinated aromatic group, and the weight ratio of the sulfonium salt to the iodonium salt is 2 to 3:1, wherein the sulfonium salt is triphenylsulfonium hexafluorophosphate; and the iodonium salt is diphenyliodonium tetrafluoroborate.

[0177] Dispersant 2wt%

[0178] Ethanol 8wt%

[0179] The filler is 11 wt %, and the filler is nano silicon dioxide, and the filler can also be other fillers.

[0180] The characteristics of the above-mentioned cationic dual-curing ink are:

[0181] For the first time, the above-mentioned specific structured epoxy cationic monomer and photoinitiated siloxane free radical monomer are introduced into the ink system, which facilitates the subsequent staged curing of the ink through the ultraviolet (UV) / heat dual triggering mechanism.

[0182] On the other hand, since the sulfonium salt / iodonium salt is modified with a fluorinated aromatic group, the cationic curing rate only decreases by 10% to 15% under an 80% humidity environment (the traditional system decreases by 40% to 60%), which effectively improves the curing efficiency of the cationic monomer.

[0183] To further illustrate how to prepare a cationic dual-cure ink, this embodiment also discloses a method for preparing a cationic dual-cure ink, which is characterized by comprising the following steps:

[0184] Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained;

[0185] The above steps yield a homogeneous first prepolymer, which is the basic material in the ink preparation process.

[0186] Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer;

[0187] Specifically, fillers and dispersants are added to the first prepolymer and mixed evenly. The resulting mixture is then dispersed in a sand mill to ensure uniform distribution of the fillers and dispersants. The resulting second prepolymer, an intermediate product in the ink preparation process, is obtained after the sand milling process.

[0188] The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

[0189] Specifically, the composite photoinitiator system is added to ethanol to uniformly disperse it. The dispersed composite photoinitiator system is then added to the second prepolymer and mixing continues. Finally, a vacuum degassing process is performed to remove bubbles generated during the mixing process to obtain the finished ink.

[0190] In this embodiment, the sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2 mm to 0.4 mm, and the rotation speed of the sand mill is 1000 rpm to 2000 rpm.

[0191] The diameter of the zirconium beads and the rotation speed of the sand mill can be adjusted according to production needs.

[0192] In this embodiment, after the mixed material is dispersed by the sand mill, the filler particle size distribution is less than 500 nm (D90).

[0193] In this embodiment, ultrasound is used to disperse the composite photoinitiator system in the solvent, and the dispersion time is 8 minutes to 15 minutes.

[0194] The dispersion time can be adjusted according to actual needs.

[0195] In this embodiment, during vacuum degassing, the vacuum degree is -0.1 MPa to -0.5 MPa, and the vacuum degassing time is 20 min to 40 min.

[0196] The vacuum treatment conditions can be adjusted according to actual needs.

[0197] Example 7

[0198] Since traditional dispersants such as polyacrylates cannot dynamically adapt to changes in system pH after curing, the interface between fillers and resins is weakened, affecting the mechanical properties and durability of inks. +Finally, the traditional anionic dispersant (such as polyacrylate) has a lower pH value after curing, and the electrostatic interaction with the resin matrix is ​​weakened, which causes the filler to fall off from the resin. There is an obvious filler-resin interface gap (gap width is about 5-10μm) in the cross section of the cured coating, which affects the performance of the ink. Using SEM observation, there is an obvious gap between the filler (such as silica) and the resin interface, such as: there is a filler with a width of 5 to 10μm in the resin gap.

[0199] In this regard, this embodiment discloses, based on Example 1, that the dispersant is a pH-responsive dispersant, and the pH-responsive dispersant is a quaternary ammonium salt-sulfonate block copolymer, wherein the molar ratio of the quaternary ammonium salt to the sulfonate is 1:0.8 to 1:1.2, preferably 1:1, and the ratio of the quaternary ammonium salt to the sulfonate can be selected according to actual needs.

[0200] The effect of using quaternary ammonium salt-sulfonate block copolymer dispersant: quaternary ammonium salt-sulfonate block copolymer is a zwitterionic block copolymer dispersant containing tertiary amine groups. The dynamic charge conversion mechanism of tertiary amine groups and sulfonic acid groups in its molecular structure realizes the interface enhancement of the dispersion stage and the curing stage, breaking through the technical bottleneck of "effective dispersion-curing failure" of traditional dispersants. It is a domestic first. It shows anionic characteristics in the preparation stage (pH=8-9) to ensure that the filler is evenly dispersed. When solidifying, the pH drops to below 6.5, and the quaternary ammonium salt-sulfonate block copolymer dispersant turns to cationic characteristics, which can strengthen the interface bonding between the filler and the resin, so that it turns to cationic characteristics when solidifying, strengthens the interface bonding between the filler (such as silica) and the resin by electrostatic action, reduces the stress concentration at the pore boundary, and forms a strong bond by using the pH response dispersant of the present invention, and the interface strength is improved by 30%. Therefore, using quaternary ammonium salt-sulfonate block copolymer dispersant, anionic characteristics are presented in the ink preparation stage of pH=8-9 to ensure dispersibility, and H is released with the cationic initiator when solidifying. + As the pH decreases, the quaternary ammonium salt-sulfonate block copolymer dispersant becomes cationic, promoting interfacial bonding between the filler and the resin. The molecular structure of this quaternary ammonium salt-sulfonate block copolymer dispersant, with its pH response threshold at pH 6.5, addresses the post-curing interface weakening issue experienced by conventional dispersants.

[0201] This quaternary ammonium salt-sulfonate block copolymer dispersant acts as a pH-responsive dispersant, achieving an integrated "dispersion-curing-binding" process. The filler-resin interface bonding strength is increased by 30%. Therefore, this quaternary ammonium salt-sulfonate block copolymer dispersant can achieve the following effects:

[0202] The preparation stage (pH=8-9) is anionic, ensuring the dispersion of fillers;

[0203] During the curing stage (pH < 6.5), the polymer becomes cationic and strengthens the filler-resin interface through electrostatic attraction.

[0204] The gap width is reduced to the nanometer level and the filler shedding phenomenon disappears.

[0205] The improvement of interface bonding strength directly reduces the stress concentration points at the micropore boundaries and reduces the risk of crack initiation.

[0206] Action mechanism of pH-responsive dispersants

[0207] The molecular structure of the quaternary ammonium salt-sulfonate block copolymer is as follows:

[0208] [Insert structural formula]

[0209]

[0210] Its pH response threshold is 6.5. When the pH is greater than 6.5, the sulfonic acid group ionizes and makes the dispersant anionic; when the pH is less than 6.5, the tertiary amine group is protonated and the dispersant becomes cationic, forming a strong electrostatic interaction with the filler surface and increasing the interfacial bonding strength by 30%.

[0211] Example effect test:

[0212] 1. The curing effect of the ink obtained in Examples 1 to 3 was tested, and the data shown in Table 1 were obtained.

[0213] Table 1

[0214]

[0215]

[0216] As can be seen from Table 1, the ink prepared in the present invention has a fast curing speed, strong adhesion and good moisture resistance retention rate.

[0217] 2. Packaging and printing applications: The ink of Example 3 was used for PET film printing in an environment with a humidity of 70% and a UV curing energy of 500 mJ / cm 2 , curing speed 30m / min, the printed product passed the following tests and the results were as follows:

[0218] Adhesion: 5B

[0219] Wear resistance: No falling off after 500 friction tests

[0220] Chemical resistance: There is no change after wiping with alcohol for 24 hours, which further illustrates that the ink prepared by the present invention has the advantages of good adhesion, good wear resistance and good chemical resistance.

[0221] 3. The inks of Examples 1 to 7 were stored at 40°C for 30 days and tested, and the following results were obtained: viscosity change rate: <5%; curing performance retention rate: >98%; no precipitation or stratification phenomenon.

[0222] Example 8

[0223] Based on Example 7, this embodiment discloses the application of a cationic dual-cure ink, comprising the following steps: printing the ink on a substrate, first triggering the curing with ultraviolet light, with the ultraviolet light treatment time being 0.1 min to 2 min, so that the ink forms a cationic skeleton with a modulus ≥1000 MPa; then entering a thermal curing stage, with the thermal curing treatment time being 2 min to 5 min, so that the siloxane free radical monomers in the ink fill the gaps in the micropores in the cationic skeleton, forming an interlocking structure, so that the size of the micropores in the cationic skeleton is <10 nm.

[0224] Comparative Example 1

[0225] The difference between Comparative Example 1 and Example 7 is that the composite photoinitiator system used in Comparative Example 1 is unmodified fluorinated aryl diphenyliodonium hexafluorophosphate, and the dispersant used in Comparative Example 1 is a sodium salt of polyacrylic acid dispersant. The other raw materials and steps are the same as in Example 1 and are not repeated here. The comparative results shown in Table 2 were obtained:

[0226] Table 2

[0227]

[0228]

[0229] As can be seen from Table 1, the ink prepared from the raw materials used in the present invention can effectively reduce the gap between the inks, improve the adhesion of the inks, and improve the curing efficiency of the inks, and is suitable for large-scale production and application.

[0230] Comparative Examples 2 to 4

[0231] The difference between Comparative Examples 2 to 4 and Example 1 is that the ratio of sulfonium salt (S) to iodonium salt (I) is changed, and the results shown in Table 3 are obtained.

[0232] Table 3

[0233] Group S:I ratio Curing time (min) Adhesion Moisture sensitivity (Δ rate) Example 1 1:1 4.2 5B 12％ Comparative Example 2 2:1 3.8 5B 10％ Comparative Example 3 3:1 4.5 4B 15％ Comparative Example 4 1:2 5.1 3B 18％

[0234] The results show that the comprehensive performance is optimal when S:I=2:1, and the ink effect is best when the ratio of sulfonium salt (S) to iodonium salt (I) is 2:1.

[0235] Effect verification

[0236] To further illustrate the function of the product obtained by the present invention, the following experiments were performed:

[0237] Experimental Example 1

[0238] High adhesion ink for metal substrates

[0239] Raw material composition (wt%): dicyclopentadiene oxirane monomer 40%, α-hydroxy ketone siloxane monomer 30%, nano-silica 15%, quaternary ammonium salt-sulfonate dispersant 2%, triphenylsulfonium hexafluorophosphate / diphenyliodonium tetrafluoroborate composite initiator 3%, the ratio of triphenylsulfonium hexafluorophosphate to diphenyliodonium tetrafluoroborate is 2:1, ethanol 10%. Among them, the epoxy cationic monomer containing caged dicyclopentadiene structure (C 10 H 12 O2), the spatial conjugated structure of its alicyclic skeleton and tertiary amine group; in the α-hydroxyketone siloxane monomer, the direct bonding mode of the α-hydroxyketone group and the siloxane group.

[0240] Preparation process:

[0241] Prepolymer preparation: Dicyclopentadiene ethylene oxide monomer and α-hydroxy ketone siloxane monomer were mixed at 80°C under nitrogen for 1 hour.

[0242] Dispersion: Add the formulated amount of nano-silica filler and quaternary ammonium salt-sulfonate dispersant and sand grind for 3 hours (particle size D90 = 450 nm).

[0243] Addition of initiator: dissolve triphenylsulfonium hexafluorophosphate and diphenyliodonium tetrafluoroborate composite initiator in ethanol, disperse by ultrasonication, add to the system and degas under vacuum.

[0244] Performance test: Test method, Adhesion test: Cross-cut test according to ASTM D3359 standard method B

[0245] Curing degree test: Determination of double bond conversion using differential scanning calorimetry (DSC)

[0246] Chemical resistance test: Salt spray test according to ASTM B117 standard

[0247] Particle size test: D90 value was measured using a laser particle size analyzer.

[0248] Operation: Coated on an aluminum plate with a surface roughness of Ra = 1.6 μm, using ultraviolet light (UV) (365 nm, 3000 mW / cm 2 ) The ink was cured for 5 minutes, and then the ink adhesion was tested using the cross-hatch method, with an adhesion of 5B and a pencil hardness of 6H. The salt spray corrosion resistance coating was tested using 5% NaCl for 500 hours, with no blistering.

[0249] The simultaneous curing of the ink prepared in this experimental example can avoid the stress accumulation of "hardening first and then shrinking", and is resistant to salt spray corrosion for 500 hours without blistering (the existing technology is usually <200 hours); the deep curing efficiency is improved (more than 90% of the curing is completed within 5 minutes), and thick coatings (>100μm) can also achieve uniform filling.

[0250] Specifically,

[0251] After testing, the ink of this experimental example performed excellently under the following conditions:

[0252] Curing speed: 3000mW / cm 2 Under ultraviolet (UV) light, the curing degree reaches more than 90% within 3 minutes (DSC test)

[0253] Adhesion: Grade 5B (ASTM D3359 standard)

[0254] Weather resistance: After 1000 hours of QUV aging test, adhesion retention rate>95%

[0255] Chemical resistance: No blistering after immersion in 5% NaCl solution for 500 hours.

[0256] Experimental Example 2

[0257] Composite substrate inks for humid environments

[0258] Raw material composition (wt%): 25% epoxy cyclohexane acrylate monomer, 35% methacrylate siloxane monomer, 18% titanium dioxide, 3% quaternary ammonium salt-sulfonate dispersant, 5% triphenylsulfonium hexafluorophosphate / diphenyliodonium tetrafluoroborate composite initiator, the ratio of triphenylsulfonium hexafluorophosphate to diphenyliodonium tetrafluoroborate is 1:1, and 14% ethanol.

[0259] Preparation process:

[0260] Prepolymer preparation: Epoxycyclohexane acrylate monomer and methacrylate siloxane monomer were mixed at 80° C. under nitrogen for 1 hour.

[0261] Dispersion: Add the formulated amount of titanium dioxide filler and quaternary ammonium salt-sulfonate dispersant and sand grind for 4 hours (particle size D90 = 300 nm).

[0262] Addition of initiator: dissolve triphenylsulfonium hexafluorophosphate and diphenyliodonium tetrafluoroborate composite initiator in ethanol, disperse by ultrasonication, add to the system and degas under vacuum.

[0263] Performance test: The ink obtained in the experimental example was applied to a glass-ceramic composite board and UV-cured for 5 minutes in a humidity environment of 90%. The water absorption rate was 0.3%, the bonding strength was 16 MPa (initial value), and the strength retention rate after 7 days was 98%, indicating that it has strong moisture resistance.

[0264] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0265] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A cationic dual-curing ink, characterized in that: Includes the following components: Epoxy cationic monomer 30wt%~50wt% Photoinitiated siloxane free radical monomer 20wt% to 40wt% Composite photoinitiator system 2wt%~5wt% pH responsive dispersant 1 wt% to 3 wt% Ethanol 5wt%~10wt% 10 wt% to 20 wt% of filler, the particle size of the filler is less than 500 nm, and the filler is nano-silicon dioxide or titanium dioxide, The composite photoinitiator system includes a sulfonium salt and an iodonium salt, wherein the sulfonium salt and / or the iodonium salt is modified with a fluoroaryl group, wherein the fluoroaryl group is a pentafluorophenyl group or a trifluoromethylphenyl group, and the weight ratio of the sulfonium salt to the iodonium salt is 2 to 3:

1. The pH-responsive dispersant is a quaternary ammonium salt-sulfonate block copolymer, wherein the molar ratio of the quaternary ammonium salt to the sulfonate is 1:0.8 to 1:1.

2.

2. The cationic dual-cure ink according to claim 1, characterized in that: The epoxy cationic monomer is one or a combination of two or more of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, dicyclopentadiene ethylene oxide monomer, and epoxycyclohexane acrylate monomer.

3. The cationic dual-cure ink according to claim 1, characterized in that: The photoinitiated siloxane free radical monomer is one or a combination of two or more of acryloxypropyltrimethoxysilane, α-hydroxyketone siloxane monomer, and methacrylate siloxane monomer.

4. The cationic dual-cure ink according to claim 1, characterized in that: The sulfonium salt is triphenylsulfonium hexafluorophosphate; and the iodonium salt is diphenyliodonium tetrafluoroborate.

5. The method for preparing a cationic dual-cure ink according to any one of claims 1 to 4, characterized in that: The following steps are involved: Add the epoxy cationic monomer and the photoinitiated siloxane free radical monomer into a reaction kettle, and fully mix them at 60°C to 90°C under nitrogen protection until a homogeneous first prepolymer is obtained; Adding a filler and a dispersant to the first prepolymer, mixing uniformly to obtain a mixed material, and dispersing the mixed material using a sand mill to obtain a second prepolymer; The composite photoinitiator system is added to ethanol and dispersed evenly. The dispersed composite photoinitiator system is then added to the second prepolymer, and the mixture is continuously mixed and vacuum degassed to obtain a finished ink.

6. The method for preparing a cationic dual-curing ink according to claim 5, characterized in that: The sand mill disperses the mixed material through zirconium beads, the diameter of the zirconium beads is 0.2mm-0.4mm, and the rotation speed of the sand mill is 1000rpm-2000rpm.

7. The method for preparing a cationic dual-cure ink according to claim 5, characterized in that: The sand mill disperses the mixed material and makes the filler particle size distribution less than 500 nm.

8. The method for preparing a cationic dual-cure ink according to claim 5, wherein: The composite photoinitiator system is dispersed in ethanol using ultrasound, and the dispersion time is 8 minutes to 15 minutes.

9. The method for preparing a cationic dual-cure ink according to claim 5, wherein: During vacuum degassing, the vacuum degree is -0.1MPa to -0.5MPa, and the vacuum degassing time is 20min to 40min.

10. The use of the cationic dual-cure ink according to any one of claims 1 to 4, characterized in that: The method comprises the following steps: printing ink on a substrate, first triggering curing with ultraviolet light, wherein the ultraviolet light treatment time is 0.1 to 2 minutes, so that the ink forms a cationic skeleton with a modulus of ≥1000 MPa; Then enter the heat curing stage, the heat curing treatment time is 2min to 5min, so that the siloxane free radical monomers in the ink fill the gaps in the micropores in the cationic skeleton to form an interlocking structure, so that the size of the micropores in the cationic skeleton is less than 10nm.

Images