Modified glass bead for pressure-sensitive adhesive as well as preparation method and application of modified glass bead

Abstract

The invention provides a modified glass bead for a pressure-sensitive adhesive as well as a preparation method and application of the modified glass bead. The preparation method of the modified glass beads comprises the following steps: carrying out Michael addition reaction on an amino silane coupling agent and methyl methacrylate to prepare a modifier with the solid content of 25-34%; and uniformly mixing the hollow glass beads and the modifier, so that the modifier forms an acrylate modified layer on the surfaces of the hollow glass beads through condensation reaction. The modified glass beads have functional groups which are the same as those in the acrylate glue solution and contain amino groups which can form hydrogen bonds with the functional groups in the acrylate glue solution, so that the modified glass beads have relatively good binding force with the acrylate glue solution, and the acrylate glue solution can be more easily immersed into gaps of aggregates; therefore, the modified glass beads can still be uniformly dispersed in the high-viscosity acrylate adhesive solution under the condition that a paddle stirrer is adopted for stirring, the phenomenon that agglomerated particles of the glass beads are difficult to dissipate is solved, and the low-cost acrylate pressure-sensitive adhesive is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hollow glass microsphere application, and particularly relates to modified glass microspheres for pressure sensitive adhesive, a preparation method and application thereof. BACKGROUND

[0002] Acrylate pressure sensitive adhesive (APSA) is a self-adhesive substance, which can form relatively firm adhesive force under small force. It is a kind of adhesive that can be tightly bonded with the adherend by applying light pressure without the aid of solvent, heat or other means. The acrylate pressure sensitive adhesive can be divided into solvent type, emulsion type and photocuring type, and has the characteristics of strong coating adaptability, fast drying speed, strong adhesion to the substrate, good leveling property and transparency.

[0003] Hollow glass microspheres mainly contain borosilicate, are pure white in color, and generally have a particle size of 10-150 μm and a wall thickness of 1-2 μm. Hollow glass microspheres have the characteristics of high compressive strength, high melting point, high resistivity, good fluidity, good sound insulation performance, small thermal conductivity coefficient and thermal shrinkage coefficient, and are known as the “space era material” in the 21st century. Hollow glass microspheres can be filled in most resin materials as low-density fillers. Meanwhile, due to the smooth surface and low oil absorption rate of hollow glass microspheres, the resin usage can be greatly reduced during use, and the viscosity does not increase much even under the premise of high addition amount, which greatly improves the production operation conditions and improves the production efficiency. Therefore, hollow glass microspheres are widely used in the field of adhesives. For example, the synthesis process of a photocuring acrylate foaming pressure sensitive adhesive is disclosed in the patent application CN113429919 A, in which a silane coupling agent is added to modify the hollow glass microspheres as foaming materials, so that the pressure sensitive adhesive has low density while maintaining good structural stability.

[0004] Although the addition of hollow glass microspheres or modified glass microspheres in the polypropylene pressure sensitive adhesive formula can make the pressure sensitive adhesive have the advantages of light weight, etc., existing acrylate pressure sensitive adhesive production enterprises add glass microspheres to the acrylate adhesive liquid prepared from other raw materials except glass microspheres during the preparation of acrylate pressure sensitive adhesive, and use a paddle stirrer to stir to obtain the final product. However, when the viscosity of the acrylate adhesive liquid is not less than 6000 mPa·s, the glass microspheres are prone to agglomeration during stirring. Meanwhile, the wettability of the acrylate adhesive liquid to the surface of the agglomerated glass microspheres is poor, and the acrylate adhesive liquid is difficult to enter the gap inside the agglomerated glass microsphere particle aggregate, so that the glass microspheres have obvious particles that are difficult to disperse in the acrylate adhesive liquid, affecting the quality of the pressure sensitive adhesive, causing waste, and thus greatly increasing the production cost.

[0005] Therefore, it is an urgent need for the existing acrylate pressure-sensitive adhesive production enterprises to research an acrylate pressure-sensitive adhesive containing hollow glass microspheres with high viscosity and low cost. SUMMARY

[0006] Therefore, the main purpose of the present application is to provide a modified glass microsphere for pressure-sensitive adhesive, a preparation method thereof and an application thereof in preparing acrylate pressure-sensitive adhesive. The modified glass microsphere has an acrylate modification layer on the surface. The modification layer has the same functional groups as acrylate and contains amino groups capable of forming hydrogen bonds with acrylate. The modification layer has good compatibility with the molecular chains in the acrylate glue solution. Therefore, the modified glass microsphere has good binding force with the acrylate glue solution, and the acrylate glue solution can easily penetrate into the internal gaps of the agglomerates. As a result, the modified glass microsphere can be uniformly dispersed in the high-viscosity acrylate glue solution even when a paddle stirrer is used for stirring, the phenomenon of difficulty in dispersing the agglomerated glass microspheres is solved, and low-cost acrylate pressure-sensitive adhesive is obtained.

[0007] To achieve the above-mentioned purpose, the first aspect of the present application provides a modified glass microsphere for pressure-sensitive adhesive, comprising a hollow glass microsphere and an acrylate modification layer coated on the surface of the hollow glass microsphere. The acrylate modification layer contains ester groups and amino groups. The interface between the hollow glass microsphere and the acrylate modification layer is combined by a condensation reaction to form a silicon-oxygen-silicon bond.

[0008] The second aspect of the present application provides a preparation method of the above-mentioned modified glass microsphere, comprising the following steps: Preparation of a modifier: under heating conditions, amino silane coupling agent and methyl methacrylate are subjected to Michael addition reaction at a molar ratio of 1: (0.95-1.05) to obtain a modifier with a solid content of 25-34 wt%; Formation of a modification layer: the hollow glass microspheres and the modifier are uniformly mixed, so that the modifier forms an acrylate modification layer on the surface of the hollow glass microspheres through a condensation reaction.

[0009] Further, in order to make the acrylate modification layer as uniformly coated as possible on the surface of the glass microspheres, the mass ratio of the hollow glass microspheres to the modifier is 100: 2.5-3.5.

[0010] Further, the step of forming the modification layer comprises: first, the modifier is sprayed onto the surface of the rotating hollow glass microspheres at 80-110°C by using a spraying method, and then the constant temperature reaction is continued to make the modifier completely solidified on the surface of the hollow glass microspheres to form the acrylate modification layer.

[0011] The third aspect of the present application provides a use of the modified glass microsphere in preparing an acrylate pressure-sensitive adhesive, wherein the modified glass microsphere and the acrylate adhesive liquid are mixed by using a paddle stirrer at a rotating speed of 40-60 r / min, so that the modified glass microsphere is uniformly dispersed in the acrylate adhesive liquid, and the acrylate pressure-sensitive adhesive is prepared.

[0012] The fourth aspect of the present application provides an acrylate pressure-sensitive adhesive, which comprises an acrylate adhesive liquid and the modified glass microsphere, and the mass percentage of the modified glass microsphere in the acrylate pressure-sensitive adhesive is 8-15%.

[0013] Therefore, compared with the prior art, the above technical solution provided by the present application has the following characteristics: 1) The modified glass microsphere forms an acrylate modified layer on the surface of the hollow glass microsphere through a condensation reaction, and the acrylate modified layer is bonded to the hollow glass microsphere at the interface through a silicon-oxygen-silicon bond, so that the acrylate modified layer and the hollow glass microsphere have strong bonding force; on the other hand, the acrylate modified layer has the same functional groups as the acrylate adhesive liquid and contains amino groups that can form hydrogen bonds with the functional groups in the acrylate adhesive liquid, thereby having good bonding force with the acrylate adhesive liquid, and the acrylate adhesive liquid is more easily immersed into the gaps of the agglomerates.

[0014] 2) The modified glass microsphere is prepared by spraying the modifier onto the surface of the hollow glass microsphere and then heating and reacting, which is simple and easy to operate.

[0015] 3) Since the modified glass microsphere has good bonding force with the acrylate adhesive liquid, the dispersion performance of the modified glass microsphere in the acrylate adhesive liquid is improved, so that the modified glass microsphere can also be uniformly dispersed in the high-viscosity acrylate adhesive liquid under the stirring action of the paddle stirrer, solving the problem of difficult dispersion of glass microsphere agglomerates, reducing the production cost while not affecting the performance of the acrylate pressure-sensitive adhesive. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The microscope photograph of the modified glass microsphere provided for Example 1 of the present application; Figure 2 The microscope photograph of the modified glass microsphere provided for Example 2 (left) and Example 3 (right) of the present application; Figure 3The dispersion state photograph of the acrylate pressure-sensitive adhesive provided for the present application example 1 and comparative examples 1-5; wherein the first row from left to right is the dispersion state photograph of example 1 and comparative examples 1-2, and the second row from left to right is the dispersion state photograph of comparative examples 3-5. Figure 4 The dispersion state photograph of the acrylate pressure-sensitive adhesive provided for the present application example 2 (left) and example 3 (right). DETAILED DESCRIPTION

[0017] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application.

[0018] The endpoints of the ranges and any values described herein are not limited to the precise values stated. The endpoints of the ranges are provided as example of the upper and lower limits for the ranges. Any value between the upper and lower limits of the range, or any value within the range, is also contemplated. For values which are less than one, or contain an exponent, the endpoint of the range is inferred to be the same value, for example 2.00 is inferred to be 2.00 and 0.5 is inferred to be 0.5.

[0019] In the present application, unless otherwise specified and / or described, all the numerical values related to the amount of components are "weight". If not specifically indicated, the terms used in the present application are the commonly used terms in the art, and the preparation processes, test methods and the like used in the embodiments are the conventional means known to those skilled in the art, and the raw materials and equipment used can be obtained from public commercial channels.

[0020] The present application mainly modifies the hollow glass microbeads by using an acrylate modifier containing the same functional group as acrylate, forms an acrylate modified layer on the surface of the hollow glass microbeads, so that the modified glass microbeads not only have good bonding force at the interface, but also have good bonding force with the acrylate glue solution; so that under the stirring action of the paddle stirrer, the modified glass microbeads can still be uniformly dispersed in the high-viscosity acrylate glue solution, solving the problem of easy agglomeration of the modified glass microbeads and difficult dispersion of the agglomerated particles, while not affecting the performance of the acrylate pressure-sensitive adhesive containing glass microbeads, effectively reducing the production cost.

[0021] Specifically, the present application adopts the following specific implementation technical solutions: A modified glass microsphere for pressure-sensitive adhesives includes hollow glass microspheres and an acrylate-modified layer coating the surface of the hollow glass microspheres. The acrylate-modified layer contains ester groups and amino groups. Because it has the same functional groups as acrylic acid and contains amino groups that can form hydrogen bonds with the functional groups in the acrylate adhesive, and has good compatibility with the molecular chains in the acrylate adhesive, the modified glass microspheres have good bonding force with the acrylate adhesive, and the adhesive can more easily penetrate into the internal gaps of the aggregates. Furthermore, the interface between the hollow glass microspheres and the acrylate-modified layer forms silicon-oxygen-silicon bonds through a condensation reaction.

[0022] If the true density of the hollow glass microspheres is too high, it will result in a small volume and high cost of the produced acrylic pressure-sensitive adhesive. Therefore, the true density of the hollow glass microspheres is 0.15 g / cm³. 3 -0.20g / cm 3 The D90 particle size is 80μm-120μm. Preferably, the hollow glass microspheres are one or a combination of two of HL15 and HL20 produced by Zhengzhou Shenglait.

[0023] The acrylate modified layer is mainly prepared by curing a modifier with a solid content of 25-34% onto the surface of hollow glass microspheres. The modifier is mainly prepared by Michael addition reaction between an aminosilane coupling agent and methyl methacrylate.

[0024] If the amount of modifier used is too large, it will waste raw materials; if the amount used is too small, it will not be able to fully coat the hollow glass microspheres, making it difficult to achieve the purpose of modifying the hollow glass microspheres. Therefore, the mass ratio of the hollow glass microspheres to the modified layer is preferably 100: 2.5 to 3.5.

[0025] A method for preparing the above-mentioned modified glass microspheres includes: placing hollow glass microspheres in a rotary furnace, spraying a modifier with a solid content of 25-34% onto the surface of the microspheres within 60 min under the conditions of a rotation speed of 6-8 rpm and a temperature of 80-110°C, and then continuing the reaction for 100-200 min to obtain the above-mentioned modified glass microspheres.

[0026] The main raw materials of the modifier include an aminosilane coupling agent and methyl methacrylate, with a molar ratio of 1:(0.95-1.05). The amino groups in the aminosilane coupling agent and the vinyl groups in methyl methacrylate undergo a Michael addition reaction under heating conditions, introducing acrylate groups into the silane coupling agent to form a new coupling agent containing silicon-oxygen-carbon bonds and acrylate groups. The ester groups and amino groups in the new coupling agent have good compatibility with the acrylate adhesive. The silicon-oxygen-carbon bonds in the new coupling agent form silicon-oxygen-silicon bonds with the silanol groups on the surface of the hollow glass microspheres through a condensation reaction. Therefore, the modified glass microspheres have good interfacial bonding strength and good compatibility with the acrylate adhesive. The aminosilane coupling agent can be aminopropyltrimethoxysilane, aminopropyltriethoxysilane, or other substances.

[0027] Specifically, the preparation method of the modifier includes: first mixing the aminosilane coupling agent and methyl methacrylate, then reacting at 85-90℃ for 60-90 min, and then adding an organic solvent to obtain a modifier with a solid content of 25-34%. The organic solvent can be toluene, xylene, ethyl acetate, etc.

[0028] An application of the above-mentioned modified glass microspheres in the preparation of acrylate pressure-sensitive adhesive. Specifically, the modified glass microspheres and acrylate adhesive are mixed using a paddle stirrer at a speed of 40-60 r / min, so that the modified glass microspheres are uniformly dispersed in the acrylate adhesive to obtain the acrylate pressure-sensitive adhesive.

[0029] The "acrylate adhesive" described in this invention refers to a mixture containing a large number of acrylate groups, derived from the mixing and reaction of existing acrylate pressure-sensitive adhesives containing hollow or modified glass microspheres, with the exception of the hollow or modified glass microspheres. Preferably, the acrylate adhesive is an oil-based, light-curing acrylate liquid with a viscosity of 6000 mPa·s to 10000 mPa·s.

[0030] To ensure that the modified glass microspheres are uniformly dispersed in the adhesive solution, the stirring time is preferably 60 to 90 minutes.

[0031] An acrylic pressure-sensitive adhesive includes an acrylic adhesive solution and the aforementioned modified glass microspheres, wherein the modified glass microspheres constitute 8-15% by mass of the acrylic pressure-sensitive adhesive.

[0032] This invention prepares a modifier by a Michael addition reaction between the amino group in an aminosilane coupling agent and the vinyl group in methyl methacrylate. This modifier simultaneously possesses acrylate groups and a silane coupling agent, exhibiting good interfacial bonding with both the acrylate adhesive and the hollow glass microspheres. Therefore, the acrylate modified layer formed after the modifier cures on the surface of the hollow glass microspheres provides excellent interfacial bonding between the modified glass microspheres and the acrylate adhesive. Consequently, under the stirring action of a paddle mixer, the modified glass microspheres can be uniformly dispersed into the acrylate adhesive, thus solving the problem of uneven dispersion of the modified glass microspheres in the acrylate adhesive due to agglomeration.

[0033] The technical solution to be protected by the present invention will be further explained and illustrated below through specific embodiments.

[0034] Example 1 This embodiment provides a modified glass microsphere for pressure-sensitive adhesive, comprising hollow glass microspheres and an acrylate modified layer coated on the surface of the hollow glass microspheres. The acrylate modified layer contains ester groups and amino groups, and the interface between the hollow glass microspheres and the acrylate modified layer is bonded by a condensation reaction to form silicon-oxygen-silicon bonds.

[0035] This embodiment also provides a method for preparing the above-mentioned modified glass microspheres, including: Preparation of the modifier: 100 moles of aminopropyltrimethoxysilane and 95 moles of methyl methacrylate were mixed and reacted at 90°C for 60 min. Then, 200% of toluene by total mass was added to obtain a modifier with a solid content of 33.3%. Spray modification: Hollow glass microspheres HL15 were placed in a rotary furnace. Under the conditions of a rotation speed of 6 rpm and a temperature of 110°C, the modifier was sprayed onto the surface of HL15 within 60 min. The reaction was then continued for another 100 min to obtain the modified glass microspheres HL15 described above. Figure 1 As shown; wherein, the mass ratio of HL15 to the modifier provided in this embodiment is 100:2.5.

[0036] This embodiment also provides an acrylic pressure-sensitive adhesive, composed of 92 parts by weight of acrylic pressure-sensitive adhesive liquid and 8 parts by weight of the modified glass microspheres provided in this embodiment. The acrylic adhesive liquid is an oil-based, light-curing acrylic liquid with a viscosity of 6000 mPa·s.

[0037] The preparation method of the above-mentioned acrylic pressure-sensitive adhesive includes: first, placing the acrylic adhesive solution in a stirring vessel, then adding modified glass microspheres, and mixing with a paddle stirrer at a speed of 60 r / min for 60 min.

[0038] Example 2 This embodiment provides a modified glass microsphere for pressure-sensitive adhesives and its preparation method, which is basically the same as the modified glass microsphere and its preparation method provided in Example 1. The main difference lies in the aminosilane coupling agent used in the preparation method and the process parameters of each step, while the remaining steps and parameters are the same. The specific differences from Example 1 are as follows: Preparation of the modifier: using aminopropyltriethoxysilane as an aminosilane coupling agent, the molar ratio of aminopropyltriethoxysilane to methyl methacrylate is 1:0.95; then reacting at 88℃ for 70 min, and then mixing in 260% of toluene to obtain a modifier with a solid content of 27.8%. Spray modification: The hollow glass microspheres are HL20. A rotary furnace is used with a rotation speed of 8 rpm and a constant temperature of 80°C. The modifier prepared in this embodiment is sprayed onto the surface of the HL20 microspheres, and the reaction continues for 200 min to obtain the modified glass microspheres HL20 described above. Figure 2 As shown on the left, the mass ratio of HL20 to the modifier prepared in this embodiment is 100:3.

[0039] This embodiment also provides an acrylic pressure-sensitive adhesive, which is composed of 85 parts by weight of acrylic pressure-sensitive adhesive liquid and 15 parts by weight of the modified glass microspheres provided in this embodiment, wherein the acrylic pressure-sensitive adhesive liquid is an oil-based light-curing acrylic liquid with a viscosity of 10000 mPa·s.

[0040] The preparation method of the above-mentioned acrylic pressure-sensitive adhesive includes: first, placing the acrylic adhesive solution in a mixing tank, then adding modified glass microspheres, and mixing with a paddle stirrer at a speed of 40 r / min for 90 min.

[0041] Example 3 This embodiment provides a modified glass microsphere for use in pressure-sensitive adhesives. The preparation method of the modified glass microspheres provided in Example 1 is basically the same as that of the modified glass microspheres provided in Example 1, with the main difference being the aminosilane coupling agent used and the process parameters for each step. The remaining steps and parameters are the same. Specifically, the differences from Example 1 are as follows: Preparation of modifier: using aminopropyltriethoxysilane as an aminosilane coupling agent, the molar ratio of aminopropyltriethoxysilane to methyl methacrylate is 1:1; react at 85℃ for 90 min, and then mix in 300% of toluene by total mass to obtain a modifier with a solid content of 25%. Spray modification: The hollow glass microspheres are HL20. A rotary furnace is used with a rotation speed of 7 rpm and a constant temperature of 100°C. The modifier prepared in this embodiment is sprayed onto the surface of the HL20 and the reaction continues for 150 min to obtain the modified glass microspheres HL20 described above. Figure 2As shown on the right, the mass ratio of HL20 to the modifier prepared in this embodiment is 100:3.5.

[0042] This embodiment also provides an acrylic pressure-sensitive adhesive, which is composed of 90 parts by weight of acrylic liquid and 10 parts by weight of the modified glass microspheres provided in this embodiment, wherein the acrylic liquid is an oil-based light-curing acrylic liquid with a viscosity of 8000 mPa·s.

[0043] The preparation method of the above-mentioned acrylic pressure-sensitive adhesive includes: first, placing the acrylic adhesive liquid in a stirring tank dispersion device, then adding modified glass microspheres, and mixing with a paddle stirrer at a speed of 50 r / min for 80 min.

[0044] Comparative Example Comparative Examples 1-5 each provide an acrylic pressure-sensitive adhesive, which is basically the same as the pressure-sensitive adhesive provided in Example 1, with the main differences as follows: In Comparative Example 1, unmodified HL15 of equal mass was used instead of modified HL15 in Example 1, and all other aspects remained the same. Comparative Example 2 uses 3-(methacryloyloxy)propyltrimethoxysilane with the same solid content instead of the modifier in Example 1, and everything else is the same; Comparative Example 3 uses vinyltrimethoxysilane with the same solid content instead of the modifier in Example 1, and everything else is the same; Comparative Example 4 uses aminopropyltrimethoxysilane with the same solid content instead of the modifier in Example 1, and everything else is the same; Comparative Example 5 uses methyl methacrylate with the same solid content instead of the modifier in Example 1, and everything else is the same; Dispersion test method: Pour the acrylic pressure-sensitive adhesives provided in Examples 1-3 and Comparative Examples 1-5 into the mold frame and observe whether there are obvious particles on the surface. The results are as follows: Figures 3-4 As shown in Table 1.

[0045] Table 1. Dispersion results of various acrylic pressure-sensitive adhesives Subject Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 2 Example 3 Dispersion Results No Particles Particles Particles Particles Particles Particles No Particles No Particles Combination Figures 3-4 As can be seen from Table 1, the modified glass microspheres in the acrylate pressure-sensitive adhesives provided in each embodiment can be uniformly dispersed therein, while different degrees of agglomerated particles appear in each comparative example.

[0046] Compared with the unmodified hollow glass microspheres in Comparative Example 1, Comparative Examples 2 to 4 used different modifiers to modify the hollow glass microspheres.

[0047] The modifier 3-(methacryloyloxy)propyltrimethoxysilane used in Comparative Example 2 contains a structure similar to acrylate and has good compatibility with acrylate resin. However, due to the lack of amino groups, its overall bonding with acrylate resin is poor. The modifier vinyltrimethoxysilane in Comparative Example 3 contains vinyl groups, but because it lacks ester and amino groups, its bonding with acrylate is poor. Comparative Example 4 contains only amino groups and no ester groups, resulting in poor overall compatibility with acrylate. Comparative Example 5, being a simple acrylic monomer, lacks good bonding with glass microspheres, making it easy to detach from the surface of the microspheres. The modified glass microspheres provided in this embodiment of the invention have a stronger bonding force with acrylate adhesive, thus enabling uniform dispersion of the modified glass microspheres even under paddle agitation conditions, thereby reducing the production cost of acrylate pressure-sensitive adhesives.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A modified glass microsphere for pressure-sensitive adhesive, characterized in that it comprises hollow glass microspheres and an acrylate modified layer coated on the surface of the hollow glass microspheres, wherein the acrylate modified layer contains ester groups and amino groups, and the interface between the hollow glass microspheres and the acrylate modified layer is bonded by a condensation reaction to form silicon-oxygen-silicon bonds.

2. The modified glass microspheres according to claim 1, characterized in that the acrylate modified layer is mainly formed by curing a modifier with a solid content of 25-34% onto the surface of hollow glass microspheres, wherein, The modifier is mainly prepared by Michael addition reaction of aminosilane coupling agent and methyl methacrylate.

3. The modified glass microspheres according to claim 1 or 2, characterized in that the true density of the hollow glass microspheres is 0.15 g / cm³. 3 -0.20g / cm 3 D90 particle size is 80μm-120μm.

4. A method for preparing the modified glass microspheres according to claim 1, 2, or 3, comprising the steps of: Preparation of modifier: Aminosilane coupling agent and methyl methacrylate undergo Michael addition reaction under heating conditions at a molar ratio of 1:(0.95~1.05) to obtain a modifier with a solid content of 25~34 wt%; Forming a modified layer: Hollow glass microspheres and the modifier are uniformly mixed, so that the modifier forms an acrylate modified layer on the surface of the hollow glass microspheres through a condensation reaction.

5. The preparation method according to claim 4, characterized in that, The mass ratio of the hollow glass microspheres to the modifier is 100: 2.5 to 3.

5.

6. The preparation method according to claim 5, characterized in that, The steps for preparing the modifier include: first mixing the aminosilane coupling agent and methyl methacrylate, then reacting at 85-90℃ for 60-90 min, and then adding an organic solvent to obtain a modifier with a solid content of 25-34%.

7. The preparation method according to claim 5 or 6, characterized in that, The steps for forming the modified layer include: at a temperature of 80–110°C, firstly, spraying the modifier onto the surface of rotating hollow glass microspheres using a spraying method, and then continuing the constant-temperature reaction to completely solidify the modifier on the surface of the hollow glass microspheres, thereby forming the acrylate modified layer.

8. The application of the modified glass microspheres according to claim 1, 2, or 3 in the preparation of acrylate pressure-sensitive adhesives, characterized in that, The modified glass microspheres and the acrylic ester adhesive with a viscosity of 6000 mPa·s to 10000 mPa·s are mixed using a paddle mixer at a speed of 40 to 60 r / min, so that the modified glass microspheres are uniformly dispersed in the acrylic ester adhesive, thereby obtaining the acrylic ester pressure-sensitive adhesive.

9. The application according to claim 8, characterized in that, The acrylate adhesive is an oil-based, light-curing acrylate liquid, and the stirring time of the paddle mixer is 60–90 min.

10. An acrylic pressure-sensitive adhesive, characterized in that, It includes an acrylic resin with a viscosity of 6000 mPa·s to 10000 mPa·s and the modified glass microspheres as described in claim 1, 2 or 3, wherein the modified glass microspheres have a mass percentage content of 8 to 15% in the acrylic pressure-sensitive adhesive.

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