Molecular particle adhesive as well as preparation method and application thereof

Abstract

The invention discloses a molecular particle adhesive as well as a preparation method and application thereof. The molecular particle adhesive comprises hexadecyl hydroxyl functionalized cage-like silsesquioxane and a boron-containing compound, and the structural formula of the hexadecyl hydroxyl functionalized cage-like silsesquioxane is as follows: the boron-containing compound is at least one of sodium tetraborate, boric acid, 1, 4-benzene diboronic acid and 4, 4 '-biphenyl diboronic acid. The molecular particle adhesive has the advantages of being high in bonding strength, wide in applicable base material range, good in storage stability, excellent in light transmittance performance, suitable for ultrathin bonding layers, convenient to use and the like, the preparation method is simple, the production cost is low, the production process is safe and environmentally friendly, and the molecular particle adhesive is suitable for large-scale industrial production and application.

Description

Technical Field

[0001] This invention relates to the field of adhesive technology, specifically to a molecular particle adhesive, its preparation method, and its application. Background Technology

[0002] Adhesives are substances used to firmly bond two or more parts or materials together (relying on interfacial adhesion and cohesion). They mainly include epoxy resin adhesives, acrylic adhesives, and polyurethane adhesives. However, traditional pure polymer adhesives often suffer from insufficient weather resistance, demanding curing conditions, and the need for additional surface treatment, which limits their practical applications to some extent.

[0003] Molecular particulate adhesives are adhesives that use molecular particles as functional units. They achieve synergistic enhancement and functionalization of the adhesive's bulk properties, and have a broader application prospect compared to pure polymer adhesives, demonstrating irreplaceable value in fields such as electronic packaging and aerospace. However, most existing molecular particulate adhesives suffer from insufficient bond strength, poor storage stability, and inconvenience in use, making it difficult to fully meet the requirements of practical applications.

[0004] Therefore, it is of great significance to develop a molecular particle adhesive with high bonding strength, good storage stability, excellent light transmittance, suitability for ultra-thin adhesive layers, and ease of use. Summary of the Invention

[0005] The purpose of this invention is to provide a molecular particulate adhesive, its preparation method, and its application.

[0006] The technical solution adopted in this invention is:

[0007] A molecular particulate adhesive comprising a hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH) and a boron-containing compound, wherein the hexadecyl hydroxyl-functionalized cage-like silsesquioxane has the following structural formula: The boron-containing compound is at least one of sodium tetraborate (Borax), boric acid (BA), 1,4-phenyldiboronic acid (PBA), and 4,4'-biphenyldiboronic acid (BDBA).

[0008] Preferably, the mass ratio of the hexadecylhydroxy-functionalized cage-like silsesquioxane to the boron-containing compound is 8:1 to 8.

[0009] Preferably, the hexadecyl hydroxyl-functionalized cage-like silsesquioxane is prepared by a method comprising the following steps: dissolving octavinyl polyhedral oligomeric silsesquioxane (VPOSS), thioglycerol and a photoinitiator in a solvent, reacting the mixture under ultraviolet light, and then separating and drying the product to obtain the hexadecyl hydroxyl-functionalized cage-like silsesquioxane.

[0010] Preferably, the molar ratio of the octavinyl polyhedral oligosilsesquioxane to thioglycerol is 1:16 to 24.

[0011] Preferably, the molar ratio of the octavinyl polyhedral oligosilsesquioxane to the photoinitiator is 1:2 to 5.

[0012] Preferably, the photoinitiator is at least one selected from 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylphenylacetone, and 1-hydroxycyclohexylphenyl methyl ketone.

[0013] Preferably, the solvent is at least one selected from tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and methanol.

[0014] Preferably, the reaction time is 1 hour to 3 hours.

[0015] Preferably, the product separation includes the following operations: concentrating the reaction solution, precipitating it 3 to 5 times with ice-cold anhydrous diethyl ether, and filtering to obtain the solid.

[0016] Preferably, the drying is carried out at a temperature of 30℃ to 50℃ for a drying time of 12h to 24h.

[0017] Preferably, the boron-containing compound is at least one of 1,4-phenyldiboronic acid and 4,4'-biphenyldiboronic acid.

[0018] A method for preparing a molecular particulate adhesive as described above includes the following steps:

[0019] 1) Disperse hexadecylhydroxy-functionalized cage-like silsesquioxane and boron-containing compounds in a solvent, then remove the solvent to obtain a composite powder;

[0020] 2) The composite powder is hot-pressed to obtain molecular particle adhesive.

[0021] Preferably, the solvent in step 1) is at least one of tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and methanol.

[0022] More preferably, the solvent in step 1) is at least one of tetrahydrofuran and methanol.

[0023] Preferably, the dispersion in step 1) is carried out at a temperature of 20°C to 80°C.

[0024] More preferably, the dispersion in step 1) is carried out at a temperature of 50°C to 60°C.

[0025] Preferably, the hot pressing in step 2) is carried out at a temperature of 30℃~80℃ and a pressure of 10MPa~20MPa.

[0026] An application of the molecular particulate adhesive described above for bonding glass substrates, stainless steel substrates or aluminum alloy substrates.

[0027] The principle of this invention: The molecular particle adhesive of this invention comprises a hexadecyl hydroxyl-functionalized cage-like silsesquioxane (prepared by functionalizing sixteen hydroxyl groups on an octavinyl polyhedral oligomeric silsesquioxane) and a boron-containing compound. The hexadecyl hydroxyl-functionalized cage-like silsesquioxane forms a cross-linked three-dimensional network structure with the boron-containing compound through dynamic borate ester bonds. At the same time, the hydrogen bonding between the hexadecyl hydroxyl-functionalized cage-like silsesquioxanes further strengthens the formed network structure, resulting in abundant dynamic borate ester bonds and hydrogen bond interactions in the adhesive system. This endows the adhesive system with excellent mechanical properties. The dynamic borate ester bonds can be reversibly formed and broken under specific conditions, allowing the adhesive to undergo structural rearrangement under external stimuli. This results in the adhesive having extremely high bonding strength on glass, stainless steel, and aluminum alloy sheets.

[0028] The beneficial effects of the present invention are: the molecular particle adhesive of the present invention has the advantages of high bonding strength, wide range of applicable substrates, good storage stability, excellent light transmittance, suitability for ultra-thin adhesive layers, and convenient use. Moreover, its preparation method is simple, production cost is low, and the production process is safe and environmentally friendly, making it suitable for large-scale industrial production and application. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the preparation process of the molecular particle adhesive in Example 1.

[0030] Figure 2 This is a photograph of the molecular particle adhesive used in Example 1.

[0031] Figure 3 SAXS diagram of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane, 4,4'-biphenyl diboronic acid, and molecular particulate adhesive in Example 1.

[0032] Figure 4 The infrared absorption spectra of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane, 4,4'-biphenyl diboronic acid, and molecular particulate adhesive in Example 1 are shown.

[0033] Figure 5 The TGA curves are for the hexadecyl hydroxyl-functionalized cage-like silsesquioxane and molecular particulate adhesive in Example 1.

[0034] Figure 6The DSC curves are for the hexadecyl hydroxyl-functionalized cage-like silsesquioxane and molecular particulate adhesive in Example 1.

[0035] Figure 7 The shear force-displacement curves are for the molecular particle adhesive in Example 1 after three bonding processes.

[0036] Figure 8 The infrared absorption spectra of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane, sodium tetraborate decahydrate, and molecular particulate adhesive in Example 2 are shown.

[0037] Figure 9 The TGA curves are for the hexadecyl hydroxyl-functionalized cage-like silsesquioxane, sodium tetraborate decahydrate, and molecular particulate adhesive used in Example 2.

[0038] Figure 10 The DSC curves are for the hexadecyl hydroxyl-functionalized cage-like silsesquioxane and molecular particle adhesive in Example 2.

[0039] Figure 11 SAXS diagram of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane, boric acid, and molecular particulate adhesive in Example 3. Detailed Implementation

[0040] The present invention will be further explained and described below with reference to specific embodiments.

[0041] Example 1:

[0042] A molecular particulate adhesive, the preparation method of which is as follows (preparation flowchart is shown below). Figure 1 As shown):

[0043] 1) Add 2.0 g of hexadecylhydroxy-functionalized cage-like silsesquioxane (POSS-16OH) to 50 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution A; add 0.25 g of 4,4'-biphenyl diboronic acid (BDBA; white crystalline powder) to 20 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution B; slowly add solution B dropwise to solution A, and continue stirring at 60 °C for 24 h to allow the methanol to evaporate completely, to obtain a composite powder (pale yellow);

[0044] 2) The composite powder is injected into a mold and then hot-pressed at 30℃ and 10MPa for 1 hour to obtain a molecular particle adhesive (denoted as POSS-16OH@BDBA-8:1; actual image as shown). Figure 2 (As shown).

[0045] Note:

[0046] The preparation method of hexadecylhydroxy-functionalized cage-like silsesquioxane (POSS-16OH) is as follows: 1.995 g of octavinyl polyhedral oligomeric silsesquioxane (VPOSS) and 6.46 g of thioglycerol were dissolved in 30 mL of tetrahydrofuran (THF) by stirring. Then, 0.28 g of 2,2-dimethoxy-2-phenylacetophenone (DMPA) was added. The mixture was then stirred and reacted under ultraviolet light (wavelength 365 nm) for 2 h. The reaction solution was then concentrated and precipitated four times with ice-cold anhydrous diethyl ether. After filtration, the solid was placed in a vacuum oven and dried at 50 °C for 12 h to obtain hexadecylhydroxy-functionalized cage-like silsesquioxane (POSS-16OH; pale yellow waxy substance).

[0047] Performance testing:

[0048] 1) The small-angle X-ray scattering (SAXS) images of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH), 4,4'-biphenyl diboronic acid (BDBA), and molecular particulate adhesive (POSS-16OH@BDBA-8:1) in this embodiment are shown below. Figure 3 As shown.

[0049] Depend on Figure 3 It can be seen that the molecular particulate adhesive exhibits uniform dispersion at the molecular level, the components in the adhesive system do not aggregate, and the crystallization peak of 4,4'-biphenyldiboronic acid also disappears after the blending reaction.

[0050] 2) The infrared absorption spectra of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH), 4,4'-biphenyl diboronic acid (BDBA), and molecular particulate adhesive (POSS-16OH@BDBA-8:1) in this embodiment are as follows: Figure 4 As shown.

[0051] Depend on Figure 4 It can be seen that the 3375 cm⁻¹ in the infrared absorption spectrum of the molecular particle adhesive is... -1 The intensity of the -OH vibration absorption peak decreased after blending, and a new peak at 1306 cm⁻¹ appeared. -1 The BO bond absorption peak indicates the presence of borate ester bonds in the molecular particulate adhesive.

[0052] 3) The thermogravimetric analysis (TGA) curves of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH) and the molecular particle adhesive (POSS-16OH@BDBA-8:1) in this embodiment are as follows: Figure 5 As shown, the differential scanning calorimetry (DSC) curve is as follows: Figure 6 As shown.

[0053] Depend on Figure 5and Figure 6 It can be seen that the thermal stability of the molecular particulate adhesive is improved to a certain extent compared with that of POSS-16OH. The molecular particulate adhesive only begins to show significant weight loss behavior at 200℃. In addition, the network structure formed by the introduction of BDBA into POSS-16OH also improves the thermal stability of the system. g .

[0054] 4) Place the molecular particle adhesive (POSS-16OH@BDBA-8:1) from this embodiment between two glass plates (square, 5mm x 5mm), clamp the two glass plates with dovetail clips, heat at 60°C for 15 minutes, and then stretch along the direction parallel to the glass plates (to achieve a shearing effect on the adhesive layer) until the two glass plates are completely separated at a stretching rate of 1mm / min. Re-bond the plates and repeat the above test process for a total of 3 times. The shear force-displacement relationship curves of the molecular particle adhesive after 3 bonding tests are shown below. Figure 7 As shown.

[0055] Note: The formula for calculating shear strength is as follows: S lap =F m / A, where F m The maximum shear force obtained in the test is represented by A, where A is the bonding area of ​​the molecular particle adhesive.

[0056] Depend on Figure 7 It can be seen that the bonding strength of the molecular particle adhesive can reach 1.7 MPa, and it can be repeatedly re-bonded more than 3 times without damaging the adhesive performance, indicating that the molecular particle adhesive has good reliability in bonding glass.

[0057] Furthermore, the same tests revealed that the molecular particle adhesive in this embodiment also exhibits strong bonding performance when used to bond stainless steel and aluminum alloys.

[0058] Example 2:

[0059] A molecular particulate adhesive, the preparation method of which is as follows:

[0060] 1) Add 2.0 g of hexadecylhydroxy-functionalized cage-like silsesquioxane (POSS-16OH; same as in Example 1) to 50 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution A; add 0.25 g of sodium tetraborate decahydrate (Borax; white crystalline powder) to 20 mL of methanol (CH3OH), and stir until fully dissolved at 80 °C and 300 rpm to obtain solution B; slowly add solution B dropwise to solution A, and continue stirring at 60 °C for 24 h to allow the methanol to evaporate completely, to obtain a composite powder (pale yellow);

[0061] 2) Inject the composite powder into the mold, and then perform hot pressing molding at a temperature of 60℃ and a pressure of 10MPa for 1 hour to obtain the molecular particle adhesive (denoted as POSS-16OH@Borax-8:1).

[0062] Performance testing:

[0063] 1) The infrared absorption spectra of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH), sodium tetraborate decahydrate (Borax), and molecular particle adhesive (POSS-16OH@Borax-8:1) in this embodiment are as follows: Figure 8 As shown.

[0064] Depend on Figure 8 It can be seen that the 3300 cm⁻¹ in the infrared absorption spectrum of molecular particle adhesives... -1 The intensity of the -OH vibration absorption peak at 1024 cm⁻¹ decreased after blending. -1 The characteristic absorption peak of borate esters is at 1442 cm⁻¹. -1 and 1353cm -1 The absorption peak for the stretching vibration of the BO bond is at 1320 cm⁻¹. -1 The characteristic absorption peak of the BO bond is at 676 cm⁻¹. -1 The absorption peak at this point is due to the bending vibration of the BO bond, indicating the presence of borate ester bonds in the molecular particulate adhesive.

[0065] 2) The TGA curves of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH), sodium tetraborate decahydrate (Borax), and molecular particle adhesive (POSS-16OH@Borax-8:1) in this embodiment are as follows: Figure 9 As shown, the DSC curves of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane and the molecular particle adhesive in this embodiment are as follows: Figure 10 As shown.

[0066] Depend on Figure 9 and Figure 10 It can be seen that the thermal stability of the molecular particulate adhesive is improved to a certain extent compared with that of POSS-16OH. In addition, the network structure formed by introducing Borax into POSS-16OH also improves the thermal stability of the system. g .

[0067] Furthermore, the same test (test method as in Example 1) revealed that the molecular particle adhesive in this example exhibits strong bonding performance when used to bond glass, stainless steel, and aluminum alloy.

[0068] Example 3:

[0069] A molecular particulate adhesive, the preparation method of which is as follows:

[0070] 1) Add 2.0 g of hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH; same as in Example 1) to 50 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution A; add 0.25 g of boric acid (BA; white crystalline powder) to 20 mL of methanol (CH3OH), and stir until fully dissolved at 80 °C and 300 rpm to obtain solution B; slowly add solution B dropwise to solution A, and continue stirring at 60 °C for 24 h to allow the methanol to evaporate completely, to obtain a composite powder (pale yellow);

[0071] 2) Inject the composite powder into the mold, and then perform hot pressing molding at a temperature of 30℃ and a pressure of 10MPa for 1 hour to obtain the molecular particle adhesive (denoted as POSS-16OH@BA-8:1).

[0072] Performance testing:

[0073] The SAXS diagrams of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane (POSS-16OH), boric acid (BA), and molecular particle adhesive (POSS-16OH@BA-8:1) in this embodiment are as follows: Figure 11 As shown.

[0074] Depend on Figure 11 It can be seen that the molecular particle adhesive exhibits uniform dispersion at the molecular level, the components in the adhesive system do not aggregate, and the crystallization peak of boric acid disappears after the blending reaction.

[0075] Furthermore, the same test (test method as in Example 1) revealed that the molecular particle adhesive in this example exhibits strong bonding performance when used to bond glass, stainless steel, and aluminum alloy.

[0076] Example 4:

[0077] A molecular particulate adhesive, the preparation method of which is as follows:

[0078] 1) Add 2.0 g of hexadecylhydroxy-functionalized cage-like silsesquioxane (POSS-16OH; same as in Example 1) to 50 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution A; add 0.25 g of 1,4-phenylenediboric acid (PBA; white crystalline powder) to 20 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution B; slowly add solution B dropwise to solution A, and continue stirring at 60 °C for 24 h to allow the methanol to evaporate completely, to obtain a composite powder (pale yellow);

[0079] 2) Inject the composite powder into the mold, and then perform hot pressing molding at a temperature of 30℃ and a pressure of 10MPa for 1 hour to obtain the molecular particle adhesive (denoted as POSS-16OH@PBA-8:1).

[0080] Tests (using the same method as in Example 1) showed that the molecular particle adhesive in this example exhibited strong bonding performance when used to bond glass, stainless steel, and aluminum alloys.

[0081] Example 5:

[0082] A molecular particulate adhesive, the preparation method of which is as follows:

[0083] 1) Add 2.0 g of hexadecylhydroxy-functionalized cage-like silsesquioxane (POSS-16OH; same as in Example 1) to 50 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution A; add 0.5 g of 1,4-phenylenediboric acid (PBA; white crystalline powder) to 20 mL of methanol (CH3OH), and stir until fully dissolved at 60 °C and 300 rpm to obtain solution B; slowly add solution B dropwise to solution A, and continue stirring at 60 °C for 24 h to allow the methanol to evaporate completely, to obtain a composite powder (pale yellow);

[0084] 2) Inject the composite powder into the mold, and then perform hot pressing molding at a temperature of 60℃ and a pressure of 10MPa for 1 hour to obtain the molecular particle adhesive (denoted as POSS-16OH@PBA-4:1).

[0085] Tests (using the same method as in Example 1) showed that the molecular particle adhesive in this example exhibited strong bonding performance when used to bond glass, stainless steel, and aluminum alloys.

[0086] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A molecular particle adhesive, characterized in that, The composition includes a hexadecyl hydroxyl-functionalized cage-like silsesquioxane and a boron-containing compound; the structural formula of the hexadecyl hydroxyl-functionalized cage-like silsesquioxane is as follows: The boron-containing compound is at least one of sodium tetraborate, boric acid, 1,4-phenyldiboronic acid, and 4,4'-biphenyldiboronic acid.

2. The molecular particle adhesive according to claim 1, characterized in that: The mass ratio of the hexadecylhydroxy-functionalized cage-like silsesquioxane to the boron-containing compound is 8:1 to 8.

3. The molecular particle adhesive according to claim 1 or 2, characterized in that: The hexadecyl hydroxyl-functionalized cage-like silsesquioxane is prepared by a method comprising the following steps: dissolving octavinyl polyhedral oligomeric silsesquioxane, thioglycerol and a photoinitiator in a solvent, reacting the mixture under ultraviolet light, and then separating and drying the product to obtain the hexadecyl hydroxyl-functionalized cage-like silsesquioxane.

4. The molecular particle adhesive according to claim 3, characterized in that: The molar ratio of the octavinyl polyhedral oligosilsesquioxane to thioglycerol is 1:16 to 24.

5. The molecular particle adhesive according to claim 3, characterized in that: The photoinitiator is at least one of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylphenylacetone, and 1-hydroxycyclohexylphenylacetone.

6. The molecular particle adhesive according to claim 3, characterized in that: The reaction time is 1 hour to 3 hours.

7. The molecular particle adhesive according to claim 1 or 2, characterized in that: The boron-containing compound is at least one of 1,4-phenyldiboronic acid and 4,4'-biphenyldiboronic acid.

8. A method for preparing a molecular particulate adhesive as described in any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Disperse hexadecylhydroxy-functionalized cage-like silsesquioxane and boron-containing compounds in a solvent, then remove the solvent to obtain a composite powder; 2) The composite powder is hot-pressed to obtain molecular particle adhesive.

9. The preparation method according to claim 8, characterized in that: The solvent in step 1) is at least one of tetrahydrofuran, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and methanol; the dispersion in step 1) is carried out at a temperature of 20℃ to 80℃; the hot pressing in step 2) is carried out at a temperature of 30℃ to 80℃ and a pressure of 10MPa to 20MPa.

10. An application of the molecular particle adhesive as described in any one of claims 1 to 7 for bonding glass substrates, stainless steel substrates or aluminum alloy substrates.

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