Rapid preparation method of three-second photocuring adhesive based on nano silicon modified epoxy resin

Abstract

The invention discloses a rapid preparation method of a three-second photocuring adhesive based on nano silicon modified epoxy resin. The light-cured coating is prepared from 100-160 parts of bisphenol A type epoxy resin, 8-12 parts of a nano silicon modifier, 5-8 parts of yttrium aluminum garnet composite silicon dioxide particles, 15-25 parts of an acylphosphine oxide photoinitiator and 1.5-3 parts of a phenoxy propyl trimethoxy silane coupling agent through the processes of pretreatment, premixing and gradient light curing. Through the synergistic effect of a gradient photocuring process and an acylphosphine oxide photoinitiator, complete curing within 3 seconds is realized under a 405nm LED light source, yttrium aluminum garnet composite silicon dioxide particles are matched with a phenoxy propyl trimethoxy silane coupling agent to form a multi-scale enhanced structure, the shear strength is improved, and the mechanical property is improved. The surface hydroxyl density of the particles subjected to air dehydration pretreatment is increased, the bonding strength retention rate is increased after the particles are aged at 160 DEG C for 800 hours, and performance degradation caused by high-temperature agglomeration of the nanoparticles is avoided.

Description

Technical Field

[0001] The present invention belongs to the field of adhesives, and more specifically, particularly relates to a rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin. Background Technique

[0002] At present, there are significant technical bottlenecks in the balance between rapid curing and mechanical properties of epoxy resin-based photocuring adhesives. In the traditional bisphenol A epoxy resin system, interface cracking is easily caused due to the concentration of curing shrinkage stress. The quantum efficiency of the conventional photoinitiator system at the 405nm band is less than 30%, and it is difficult to achieve three-second rapid curing; there are inherent defects in the filler dispersion technology. The packing density of ordinary silica particles is less than 65%, and the surface hydroxyl groups are easily deactivated during high-temperature treatment, resulting in a sharp drop in the interfacial bonding strength between the resin matrix and the filler;

[0003] In addition, in the existing coupling agent hydrolysis process, a single constant temperature treatment is mostly used, and the hydrolysis degree of the silane coupling agent fluctuates by more than ±15%, seriously affecting the stability of interfacial chemical bonding. In terms of curing process control, traditional stepwise light irradiation initiation leads to a sudden change in the curing gradient, and the measured temperature difference inside the adhesive layer reaches more than 40°C, causing local thermal stress concentration defects. Moreover, the existing photocuring algorithm does not consider the influence of the dynamic change of resin viscosity on light transmittance, and the measured critical curing time deviation exceeds ±1.2 seconds, which cannot meet the strict requirements for curing time accuracy in fields such as precision electronic assembly. Therefore, we propose a rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin to effectively solve the above technical problems. Summary of the Invention

[0004] The purpose of the present invention is to solve the shortcomings existing in the prior art, and to propose a rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin. This method effectively solves the dilemma that it is difficult to have both high curing speed and good mechanical properties in the prior art, shows significant application advantages in fields such as microelectronic packaging and optical device assembly, and the comprehensive performance indicators are improved compared with the industry benchmark products.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin, the three-second photocuring adhesive based on nano-silicon modified epoxy resin is prepared from 100-160 parts of bisphenol A epoxy resin, 8-12 parts of nano-silicon modifier, 5-8 parts of yttrium aluminum garnet composite silica particles, 15-25 parts of acylphosphine oxide photoinitiator, and 1.5-3 parts of phenoxypropyltrimethoxysilane coupling agent;

[0007] The preparation method includes the following steps:

[0008] S1. Pretreatment: Dehydrate yttrium aluminum garnet composite silica particles in vacuum at 160 - 180 °C for 1.5 h;

[0009] S2. Premixing: Stir and mix bisphenol A epoxy resin and phenoxypropyltrimethoxysilane coupling agent at 45 °C at 800 r / min until the mixing index is met. The calculation formula for the mixing index M is:

[0010] In the formula, η is the viscosity of the system, with the unit of mPa·s; N is the stirring speed, with the unit of rpm; T K is the absolute temperature, and t0 is the predetermined mixing time;

[0011] S3. Gradient photocuring: Place the mixture under a 405 nm LED light source for segmented irradiation. Among them, the irradiance in the first stage I1 = 80 - 100 mW / cm 2 , and the irradiance in the second stage I2 = 150 - 180 mW / cm 2 ,

[0012] Among them, the switching condition from the irradiance in the first stage to the irradiance in the second stage satisfies the following conditions:

[0013] In the formula, η pre and η post are the viscosities of the system before and after the stage conversion, respectively.

[0014] Preferably, the particle size distribution of the yttrium aluminum garnet composite silica particles satisfies the following conditions:

[0015]

[0016] In the formula, C m is the mass concentration of the composite particles, with the unit of g / cm 3 ; D 90 , D 10 and D 50 represent the corresponding percentile particle sizes, with the unit of μm; Through the above conditions, the packing density of the particles is increased.

[0017] Preferably, the calculation formula for the total photocuring time of the gradient photocuring in step S3 is:

[0018]

[0019] In the formula, T c is the critical curing time, with the unit of s; η v is the viscosity of the modified resin, with the unit of Pa·s; I is the irradiance at a wavelength of 405 nm, with the unit of mW / cm 2; α is the light intensity attenuation coefficient, and the value range of the light intensity attenuation coefficient is 0.68 ≤ α ≤ 0.72; E a is the activation energy, and the value range is 65 ≤ E_a ≤ 75 kJ / mol; R is the gas constant, and the calculation formula of the coefficient k1 is:

[0020] where, φ s is the filler volume fraction, θ is the resin / filler contact angle, ε r is the system dielectric constant, β is the modification degree of nano-silicon, and the value is 0 ≤ β ≤ 1.

[0021] Preferably, for the calculation of the gradient photocuring time, a gradient magnetic field of 0.3 - 0.5 T is applied along the irradiation direction during the stage conversion, and the magnetic field intensity distribution is positively correlated with the viscosity change rate ;

[0022] The calculation of the gradient photocuring time introduces a stress relaxation compensation factor σ r , and the expression is:

[0023]

[0024] In the formula, E is the elastic modulus of the resin, τ m is the maximum relaxation time, and the introduction of the stress relaxation compensation factor σ r reduces the curing shrinkage stress.

[0025] Preferably, the yttrium aluminum garnet composite silica particles are subjected to a two-stage surface activation treatment: the first stage is treated with a 2.5 mol / L silane coupling agent ethanol solution at 65 °C for 40 minutes, and the second stage is treated with a 0.3 mol / L titanate solution in an ultrasonic environment for 15 minutes.

[0026] Preferably, the nano-silicon modifier has a core-shell structure. The core is spherical nano-silicon with a particle size of 25 - 35 nm, and the shell is composed of a copolymer of fluorinated polysiloxane and glycidyl methacrylate. The shell layer thickness is 8 - 12 nm;

[0027] For the core-shell nano-silicon modifier, it is characterized in that the fluorine atom content in the shell copolymer satisfies:

[0028] C F = 0.85β - 0.03T g + 0.12ln(α f );

[0029] In the formula, C F is the molar percentage of fluorine atoms, β is the modification degree of nano-silicon, T g is the glass transition temperature of the copolymer, and α f is the surface energy correction coefficient.

[0030] Preferably, a plasma bombardment step is inserted after the first stage of the two-stage surface activation treatment. An Ar / O2 mixed gas is used, and the radio frequency power density is 0.8 - 1.2 W / cm 3 , and the treatment time t p satisfies:

[0031] In the formula, ΔH is the difference in the hydroxyl concentration on the particle surface, and this treatment improves the interfacial bonding strength.

[0032] Preferably, the yttrium aluminum garnet composite silica particles need to be subjected to three-stage wetting treatment before vacuum dehydration, which specifically includes: first, ultrasonically vibrate with a 0.5 - 0.8 mol / L sodium hydroxide solution at 40 °C for 30 minutes, keeping the ultrasonic frequency at 28 kHz and the power density at 12 W / L; then soak with a 2 - 3 wt% γ-aminopropyltriethoxysilane ethanol solution under reduced pressure to 50 kPa, controlling the liquid-solid ratio at 5:1, and the treatment time is 60 ± 2 minutes; finally, perform surface passivation treatment in a supercritical carbon dioxide environment at a pressure of 18 - 20 MPa and a temperature of 45 °C, with a carbon dioxide flow rate of 0.8 L / min, and continuously treat for 90 minutes; the three-stage treatment increases the hydroxyl density on the particle surface from 1.2 per nm 2 to 3.5 per nm 2 , and form a three-dimensional dendritic wetting layer structure.

[0033] Preferably, a ultrasonic reaction kettle with a gradually changing pore size structure is used in the titanate solution treatment stage. Its inner wall is provided with a multi-layer titanium alloy filter device, and the pore sizes of the upper, middle, and lower three layers of filters are 0.8 mm, 0.5 mm, and 0.3 mm respectively, and a gradient cavity of 3 - 5 cm is formed between adjacent layers; during the treatment process, the ultrasonic power is adjusted in three steps of "low - high - low =":

[0034] Keep it at 0.5 W / cm for the first 5 minutes 2 , rise to 2.4 W / cm in the middle 8 minutes 2 and simultaneously heat up to 75 °C at a rate of 0.3 °C / s, and finally drop back to 0.8 W / cm in the last 2 minutes 2 .

[0035] Technical effects and advantages of the present invention: The rapid preparation method of the three-second photocuring adhesive based on nano-silicon modified epoxy resin provided by the present invention, compared with traditional solid products, through the synergistic effect of the gradient photocuring process and acylphosphine oxide photoinitiator, can achieve complete curing within 3 seconds under a 405 nm LED light source. The yttrium aluminum garnet composite silica particles cooperate with phenoxypropyltrimethoxysilane coupling agent to form a multi-scale reinforcement structure, and the shear strength is improved;

[0036] Secondly, after vacuum dehydration pretreatment, the hydroxyl density on the surface of the particles is increased, and the retention rate of the bonding strength after aging at 160 °C for 800 hours is increased, avoiding the performance deterioration caused by the high-temperature agglomeration of nanoparticles. The mixing index and the photo-curing time algorithm realize the real-time coupling regulation of the viscosity of bisphenol A epoxy resin and the photo-initiation efficiency, and the fluctuation of the curing critical time between batches is reduced. Brief Description of the Drawings

[0037] Figure 1 It is a flow chart of a rapid preparation method of a three-second photo-curing adhesive based on nano-silicon modified epoxy resin according to the present invention. Detailed Embodiments

[0038] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0039] The present invention provides a rapid preparation method of a three-second photo-curing adhesive based on nano-silicon modified epoxy resin as Figure 1 shown. Through innovative component design and intelligent process control, a nano-silicon modified epoxy adhesive with both rapid curing and high performance has been successfully developed. Bisphenol A epoxy resin is synergistically strengthened by a nano-silicon modifier and a gradient photo-curing process, achieving high-strength curing within 3 seconds, with improved efficiency compared to traditional processes;

[0040] Yttrium aluminum garnet composite silica particles form a stable three-dimensional reinforcement network under vacuum dehydration and coupling agent optimization treatment, making the shear modulus of the adhesive layer reach 1.45 GPa; the segmented gradient photo-curing combined with the dynamic viscosity control algorithm effectively suppresses the curing shrinkage stress, and at the same time accurately controls the parameters of each process stage to ensure the consistency of batch production;

[0041] Before vacuum dehydration, the yttrium aluminum garnet composite silica particles need to be subjected to three-stage wetting treatment, which specifically includes: first, ultrasonic vibration treatment with a 0.5-0.8 mol / L sodium hydroxide solution at 40 °C for 30 minutes, with the ultrasonic frequency maintained at 28 kHz and the power density at 12 W / L; then soaking treatment with a 2-3 wt% γ-aminopropyltriethoxysilane ethanol solution under reduced pressure to 50 kPa, with the liquid-solid ratio controlled at 5:1 and the treatment time of 60 ± 2 minutes; finally, surface passivation treatment is carried out in a supercritical carbon dioxide environment at a pressure of 18-20 MPa and a temperature of 45 °C, with a carbon dioxide flow rate of 0.8 L / min and continuous treatment for 90 minutes; the three-stage treatment increases the hydroxyl density on the particle surface from 1.2 per nm 2 to 3.5 per nm2 , and form a three-dimensional dendritic wetting layer structure;

[0042] The method includes:

[0043] The three-second photocuring adhesive based on nano-silicon modified epoxy resin is prepared from 100 - 160 parts of bisphenol A type epoxy resin, 8 - 12 parts of nano-silicon modifier, 5 - 8 parts of yttrium aluminum garnet composite silica particles, 15 - 25 parts of acylphosphine oxide photoinitiator, and 1.5 - 3 parts of phenoxypropyltrimethoxysilane coupling agent;

[0044] Among them, the nano-silicon modifier has a core-shell structure. The inner core is spherical nano-silicon with a particle size of 25 - 35 nm, and the outer shell is composed of a copolymer of fluorinated polysiloxane and glycidyl methacrylate, and the shell thickness is 8 - 12 nm;

[0045] The core-shell nano-silicon modifier is characterized in that the fluorine atom content in the shell copolymer satisfies:

[0046] C F = 0.85β - 0.03T g + 0.12ln(α f );

[0047] In the formula, C F is the molar percentage of fluorine atoms, β is the nano-silicon modification degree, T g is the glass transition temperature of the copolymer, and α f is the surface energy correction coefficient.

[0048] The preparation method includes the following steps:

[0049] S1. Pretreatment, dehydrating the yttrium aluminum garnet composite silica particles in vacuum at 160 - 180 °C for 1.5 h;

[0050] Among them, the particle size distribution of the yttrium aluminum garnet composite silica particles satisfies the following conditions:

[0051]

[0052] In the formula, C m is the mass concentration of the composite particles, with the unit of g / cm 3 ; D 90 , D 10 and D 50 respectively represent the corresponding percentile particle sizes, with the unit of μm; the packing density of the particles is increased through the above conditions;

[0053] It should be noted that the yttrium aluminum garnet composite silica particles are subjected to a two-stage surface activation treatment: in the first stage, they are treated with a 2.5 mol / L ethanol solution of silane coupling agent at 65 °C for 40 minutes, and in the second stage, they are treated with a 0.3 mol / L titanate solution under ultrasonic environment for 15 minutes. A plasma bombardment step is inserted after the first stage of the two-stage surface activation treatment, using an Ar / O2 mixed gas with a radio frequency power density of 0.8 - 1.2 W / cm 3 , and the treatment time t p satisfies:

[0054] In the formula, ΔH is the difference in the hydroxyl concentration on the particle surface, and this treatment improves the interfacial bonding strength;

[0055] During the treatment stage with the titanate solution, an ultrasonic reaction kettle with a gradually changing pore size structure is used. Its inner wall is provided with a multi-layer titanium alloy filter device, and the pore sizes of the upper, middle, and lower three layers of filters are 0.8 mm, 0.5 mm, and 0.3 mm respectively, forming a gradient cavity of 3 - 5 cm between adjacent layers; during the treatment process, the ultrasonic power is adjusted in three steps of "low - high - low": it is maintained at 0.5 W / cm for the first 5 minutes 2 , rises to 2.4 W / cm in the middle 8 minutes 2 and at the same time heats up to 75 °C at a rate of 0.3 °C / s, and drops back to 0.8 W / cm in the last 2 minutes 2 .

[0056] S2. Premixing: Bisphenol A epoxy resin and phenoxypropyltrimethoxysilane coupling agent are stirred and mixed at 45 °C at 800 r / min until the mixing index is satisfied. The calculation formula for the mixing index M is:

[0057] In the formula, η is the system viscosity, with the unit of mPa·s; N is the stirring speed, with the unit of rpm; T K is the absolute temperature, and t0 is the predetermined mixing time;

[0058] S3. Gradient photocuring: The mixture is placed under a 405 nm LED light source for segmented irradiation. Among them, the irradiance I1 in the first stage = 80 - 100 mW / cm 2 , and the irradiance I2 in the second stage = 150 - 180 mW / cm 2 ,

[0059] Among them, the switching condition from the irradiance in the first stage to the irradiance in the second stage satisfies the following conditions:

[0060] In the formula, η pre and η post are the system viscosities before and after the stage conversion respectively;

[0061] In step S3, the calculation formula for the total photocuring time of gradient photocuring is:

[0062]

[0063] In the formula, T c is the critical curing time, with the unit of s; η v is the viscosity of the modified resin, with the unit of Pa·s; I is the irradiance at a wavelength of 405 nm, with the unit of mW / cm 2 ; α is the light intensity attenuation coefficient, and the value range of the light intensity attenuation coefficient is 0.68 ≤ α ≤ 0.72; E a is the activation energy, and the value range is 65 ≤ E_a ≤ 75 kJ / mol; R is the gas constant, and the calculation formula for the coefficient k1 is:

[0064] Among them, φ s is the filler volume fraction, θ is the resin / filler contact angle, ε r is the system dielectric constant, β is the degree of modification of nano-silicon, and the value is 0 ≤ β ≤ 1;

[0065] For the calculation of the gradient photocuring time, a gradient magnetic field of 0.3 - 0.5T is applied along the irradiation direction during the stage conversion, and the magnetic field intensity distribution is positively correlated with the viscosity change rate ;

[0066] The calculation of the gradient photocuring time introduces a stress relaxation compensation factor σ r , and the expression is:

[0067]

[0068] In the formula, E is the elastic modulus of the resin, τ m is the maximum relaxation time, and the introduction of the stress relaxation compensation factor σ r reduces the curing shrinkage stress.

[0069] According to the above method, there are the following examples in specific implementation:

[0070] Example 1

[0071] Prepare the adhesive according to the following ratio:

[0072] 120 parts of bisphenol A epoxy resin, 10 parts of nano-silicon modifier (mass fraction 4%), 6 parts of yttrium aluminum garnet composite silica particles (treated by vacuum dehydration at 160 °C), 20 parts of acylphosphine oxide photoinitiator (TPO-L), 2 parts of phenoxypropyltrimethoxysilane coupling agent;

[0073] Preparation steps:

[0074] Pretreatment: The yttrium aluminum garnet composite silica particles are dehydrated in vacuum at 170 °C for 1.5 hours, and the measured particle size distribution satisfies (C_m = 0.6 g / cm 3 Cm = 0.6 g / cm3), and the packing density of the particles reaches 78.4% (only 64.2% for the untreated control group);

[0075] Premixing: Stir and mix at 45 °C at 800 r / min for 55 minutes, and the mixing index is calculated to be M = 12.7 (η = 580 mPa·s, T K = 318 K).

[0076] Gradient photocuring:

[0077] The first stage: I1 = 90 mW / cm 2 , and when the system viscosity η pre = 320 mPa·s, switch to the second stage;

[0078] The second stage: I2 = 160 mW / cm 2 , and the switching condition is satisfied The total curing time T c = 3.1 s (calculated according to η v = 0.58 Pa·s, α = 0.70, E a = 70 kJ / mol)

[0079] Performance Index Example 1 Ratio Example (without nano-silicon modification) Curing Time (s) 3.1 9.6 Shear Strength (MPa) 18.7 12.4 Strength Retention Rate after Aging at 160°C for 800 h 93.5％ 68.2％ Particle Size Span (D50 D90 - D10) 0.29 0.52

[0080] Example 2

[0081] Prepare the adhesive according to the following ratio:

[0082] 100 parts of bisphenol A epoxy resin, 12 parts of nano-silica modifier (mass fraction 5%), 8 parts of yttrium aluminum garnet composite silica particles (treated by vacuum dehydration at 180 °C), 25 parts of acylphosphine oxide photoinitiator (TPO-L), 3 parts of phenoxypropyltrimethoxysilane coupling agent;

[0083] Preparation steps:

[0084] Pretreatment: After vacuum dehydration at 180 °C, D 50 = 6.8 μm, C m = 0.72 g / cm 3 is satisfied when

[0085] Premixing: Stir at 45 °C until the mixing index M = 14.3 and then terminate (it takes 48 minutes, and the stirring speed is adjusted to 850 r / min);

[0086] Gradient photocuring:

[0087] The first stage I1 = 100 mW / cm 2 , when η pre = 280 mPa·s, it switches to I2 = 180 mW / cm 2 The total curing time T c = 2.8 s T (calculated according to the formula );

[0088] Performance Index Example 2 Traditional Step Curing Process Curing Time (s) 2.8 8.9 Interface Peel Strength (N / mm) 42.6 27.3 Curing Shrinkage Rate (%) 1.7 4.2 Coefficient of Thermal Expansion (ppm / °C) 35 68

[0089] In the above two embodiments:

[0090] In Example 1, the packing density of yttrium aluminum garnet composite particles is increased to 78.4% (only 64.2% in the comparative example), and the shear strength is increased by 50.8%.

[0091] Through controlling the light intensity switching point, the gradient photocuring process reduces the curing shrinkage rate of Example 2 by 59.5% compared with the traditional process, proving that stress concentration is effectively inhibited.

[0092] In Example 1, the mixing index algorithm optimizes the stirring time to 55 minutes, saving 31% energy consumption compared with the empirical method (usually 80 minutes).

[0093] The addition of nano-silicon modifier (12 parts in Example 2) reduces the thermal expansion coefficient to 35 ppm / °C, meeting the stringent requirements of microelectronic packaging for CTE matching.

[0094] The above embodiments can illustrate that the preparation method of the present invention successfully achieves the technical goal of high-strength curing within 3 seconds through quantitatively controlling the surface state of particles, dynamically regulating the mixing index, and precisely segmenting light irradiation; all the data of the embodiments meet the limiting requirements of the material ratio, process algorithm, and performance index in the claims.

[0095] In summary, compared with the traditional solid products, through the synergistic effect of the gradient photocuring process and acylphosphine oxide photoinitiator, the present invention realizes complete curing within 3 seconds under a 405 nm LED light source. The yttrium aluminum garnet composite silica particles are combined with phenoxypropyltrimethoxysilane coupling agent to form a multi-scale reinforcement structure, and the shear strength is improved;

[0096] Secondly, the surface hydroxyl density of the particles after vacuum dehydration pretreatment is increased, and the adhesion strength retention rate is improved after aging at 160 °C for 800 hours, avoiding the performance deterioration caused by high-temperature agglomeration of nanoparticles. The mixing index and the photocuring time algorithm realize the real-time coupling regulation of the viscosity of bisphenol A epoxy resin and the photoinitiating efficiency, and the fluctuation of the curing critical time between batches is reduced.

[0097] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A rapid preparation method of a three - second photocuring adhesive based on nano - silicon modified epoxy resin, characterized in that The three-second photocuring adhesive based on nano-silicon modified epoxy resin is prepared from 100-160 parts of bisphenol A type epoxy resin, 8-12 parts of nano-silicon modifier, 5-8 parts of yttrium aluminum garnet composite silica particles, 15-25 parts of acylphosphine oxide photoinitiator, and 1.5-3 parts of phenoxypropyltrimethoxysilane coupling agent; The preparation method includes the following steps: S1. Pretreatment: dehydrate the yttrium aluminum garnet composite silica particles in vacuum at 160-180 °C for 1.5 h; S2. Premixing: stir and mix bisphenol A type epoxy resin and phenoxypropyltrimethoxysilane coupling agent at 45 °C at 800 r / min until the mixing index is satisfied; S3. Gradient photocuring: The mixture is placed under a 405 nm LED light source for segmented irradiation. Among them, the irradiance in the first stage I1 = 80 - 100 mW / cm 2 , and the irradiance in the second stage I2 = 150 - 180 mW / cm 2 , where...

2. The rapid preparation method of the three - second photocuring adhesive based on nano - silicon modified epoxy resin according to claim 1, wherein, The particle size distribution of the yttrium aluminum garnet composite silica particles satisfies the following conditions: where C m is the mass concentration of the composite particles, with the unit of g / cm 3 ; D 90 , D 10 and D 50 respectively represent the corresponding percentile particle sizes, with the unit of μm; the packing density of the particles is increased by the above conditions.

3. The rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin according to claim 1, characterized in that, The calculation formula for the total photocuring time of the gradient photocuring in step S3 is: where T c is the critical curing time in seconds; η v is the viscosity of the modified resin, with the unit of Pa·s; I is the irradiance at a wavelength of 405 nm, with the unit of mW / cm 2 ; α is the light intensity attenuation coefficient, and the value range of the light intensity attenuation coefficient is 0.68 ≤ α ≤ 0.72; E a is the activation energy, and the value range is 65 ≤ E_a ≤ 75 kJ / mol; R is the gas constant. The calculation formula for the coefficient k1 is: Among them, φ s is the filler volume fraction, θ is the resin / filler contact angle, ε r is the system dielectric constant, β is the modification degree of nano-silicon, and the value range is 0 ≤ β ≤ 1.

4. The rapid preparation method of a three - second photocuring adhesive based on nano - silicon modified epoxy resin according to claim 3, characterized in that, For the calculation of the gradient photocuring time, a gradient magnetic field of 0.3 - 0.5 T is applied along the irradiation direction during the phase transition, and the magnetic field strength distribution is positively correlated with the viscosity change rate; The calculation of the gradient photocuring time introduces a stress relaxation compensation factor σ r , and the expression is: where E is the elastic modulus of the resin, τ m is the maximum relaxation time, and the introduction of the stress relaxation compensation factor σ r reduces the curing shrinkage stress.

5. The rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin according to claim 2, characterized in that The yttrium aluminum garnet composite silica particles are subjected to two-stage surface activation treatment: the first stage is treated with a 2.5 mol / L silane coupling agent ethanol solution at 65 °C for 40 minutes, and the second stage is treated with a 0.3 mol / L titanate solution in an ultrasonic environment for 15 minutes.

6. The rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin according to claim 1, characterized in that, The nano-silicon modifier has a core-shell structure, the core is spherical nano-silicon with a particle size of 25-35 nm, and the shell is composed of a copolymer of fluorinated polysiloxane and glycidyl methacrylate, and the shell layer thickness is 8-12 nm; For the core-shell nano-silicon modifier, the fluorine atom content in the shell copolymer is controlled to satisfy: G F = 0.85β - 0.03T g + 0.12ln(α f ); where C F is the molar percentage of fluorine atoms, β is the modification degree of nano-silicon, T g is the glass transition temperature of the copolymer, and α f is the surface energy correction coefficient.

7. The rapid preparation method of a three-second photocuring adhesive based on nano-silicon modified epoxy resin according to claim 5, characterized in that, After the first stage of the two-stage surface activation treatment, a plasma bombardment step is inserted, using an Ar / O2 mixed gas, with a radio frequency power density of 0.8-1.2 W / cm 3 , treatment time t p satisfies: In the formula, ΔH is the difference in the concentration of hydroxyl groups on the particle surface, and this treatment improves the interfacial bonding strength.

8. The rapid preparation method of the three-second photocuring adhesive based on nano-silicon modified epoxy resin according to claim 1, characterized in that, The yttrium aluminum garnet composite silica particles need to be subjected to three-stage wetting treatment before vacuum dehydration, which specifically includes: first, ultrasonic vibration treatment with a 0.5-0.8 mol / L sodium hydroxide solution at 40 °C for 30 minutes, with the ultrasonic frequency maintained at 28 kHz and the power density at 12 W / L; subsequently, soaking treatment with a 2-3 wt% γ-aminopropyltriethoxysilane ethanol solution under reduced pressure to 50 kPa, with the liquid-solid ratio controlled at 5:1 and the treatment time of 60 ± 2 minutes; finally, surface passivation treatment in a supercritical carbon dioxide environment at a pressure of 18-20 MPa and a temperature of 45 °C, with a carbon dioxide flow rate of 0.8 L / min and continuous treatment for 90 minutes; the three-stage treatment increases the hydroxyl density on the particle surface from 1.2 per nm 2 to 3.5 per nm 2 and forms a three-dimensional dendritic wetting layer structure.

9. The rapid preparation method of a three-second light-curing adhesive based on nano-silicon modified epoxy resin according to claim 7, characterized in that, The titanium ester solution treatment stage is supported by an ultrasonic reactor with a gradually changing pore size structure. Its inner wall is provided with a multi-layer titanium alloy filter device. The pore sizes of the upper, middle, and lower three-layer filters are 0.8 mm, 0.5 mm, and 0.3 mm respectively, and a gradient cavity of 3-5 cm is formed between adjacent layers; during the treatment process, the ultrasonic power is adjusted in three steps of "low-high-low": it is maintained at 0.5 W / cm for the first 5 minutes 2 , rises to 2.4 W / cm in the middle 8 minutes 2 and at the same time heats up to 75 °C at a rate of 0.3 °C / s, and drops back to 0.8 W / cm in the last 2 minutes 2 .

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