Hollow polymer microsphere as well as preparation method and application thereof
By preparing hollow polymer microspheres from modified attapulgite powder, the problems of structural instability and poor compatibility of low dielectric fillers in the copper clad laminate resin system were solved, and the low dielectric properties and excellent mechanical properties of the copper clad laminate were achieved.
Patent Information
- Application Number
- CN202511110235.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-08
- Publication Date
- 2025-10-17
AI Technical Summary
The low dielectric fillers used in existing copper clad laminate resin systems have problems with structural instability and poor compatibility, which leads to a decrease in the compressive and electrical properties of the copper clad laminates.
Hollow polymer microspheres were prepared by calcining and modifying modified attapulgite powder as a template. The microspheres were then added into the copper clad laminate resin system to form a hollow structure to improve compatibility and stability.
Significantly reduce the dielectric constant and dielectric loss of copper clad laminates, enhance compressive performance, and improve the mechanical properties of copper clad laminates, while complying with the development trend of green materials.
Smart Images
Figure CN120795355A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of functional polymer materials, in particular to a hollow polymer microsphere and a preparation method and application thereof. BACKGROUND
[0002] With the rapid development of 5G technology and high-frequency high-speed electronic equipment, people have higher performance requirements for copper-clad plates, such as low dielectric constant (Dk) and low dielectric loss (Df). At present, the commonly used low dielectric fillers of the copper-clad plate resin system include hollow glass microspheres, fused silica, polytetrafluoroethylene microspheres, etc. There are many problems after adding the low dielectric filler to the copper-clad plate resin system: for example, the structure of the hollow glass microspheres is unstable, and the "ball breaking" phenomenon easily occurs under high temperature and high pressure, resulting in a decrease in the pressure resistance of the copper-clad plate; the compatibility of the low dielectric filler with the copper-clad plate resin system is poor, and the interfacial bonding force is insufficient, which affects the mechanical properties and electrical properties of the copper-clad plate.
[0003] Therefore, it is urgent to develop a new type of low dielectric filler which has good compatibility with the copper-clad plate resin system, so as to make the copper-clad plate material have excellent mechanical properties and electrical properties. SUMMARY
[0004] The present application aims at providing a hollow polymer microsphere and a preparation method and application thereof to overcome the deficiencies of the prior art.
[0005] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:
[0006] The present application provides a preparation method of a hollow polymer microsphere, comprising the following steps:
[0007] 1) mixing modified attapulgite powder, cyanate ester resin, initiator and solvent to obtain a mixed emulsion;
[0008] 2) performing emulsion polymerization reaction on the mixed emulsion to obtain polymer microspheres;
[0009] 3) performing acid pickling on the polymer microspheres to obtain the hollow polymer microspheres.
[0010] Preferably, the modified attapulgite powder in step 1) is silane coupling agent modified attapulgite powder.
[0011] The preparation method of the silane coupling agent modified attapulgite powder comprises: calcining attapulgite powder, and adding a silane coupling agent to the calcined attapulgite powder for modification.
[0012] Preferably, the calcination temperature is 500-800℃, the calcination time is 5-8h, and the temperature rising rate for rising to the calcination temperature is 1-3℃ / min.
[0013] Preferably, the silane coupling agent has a mass of 0.1-1% of the mass of the attapulgite powder;
[0014] The modification is stirring modification, the stirring modification is performed at a temperature of 80-100 DEG C, a stirring modification speed of 800-1500 rpm, and a stirring modification time of 1-5 h.
[0015] Preferably, the modified attapulgite powder has a mass of 10-25% of the mass of the mixed emulsion, the cyanoate resin has a mass of 50-70% of the mass of the mixed emulsion, and the initiator has a mass of 0.1-0.5% of the mass of the cyanoate resin.
[0016] Preferably, the emulsion polymerization reaction is performed at a temperature of 60-80 DEG C for 2-4 h.
[0017] Preferably, the acid pickling agent is hydrochloric acid or nitric acid, and the mass fraction of the hydrochloric acid or nitric acid is independently 0.5-2%.
[0018] The acid pickling is performed for 1-5 h.
[0019] The application further provides the hollow polymer microspheres prepared by the preparation method.
[0020] The application further provides application of the hollow polymer microspheres in copper-clad plates, wherein the hollow polymer microspheres are added into a copper-clad plate resin system.
[0021] Preferably, the copper-clad plate resin system comprises an epoxy resin, a dicyandiamide curing agent, an accelerator, and a solvent I.
[0022] The mass ratio of the hollow polymer microspheres to the epoxy resin is 10-20:100.
[0023] The application has the following beneficial effects:
[0024] The application modifies attapulgite powder by calcination and modification with a silane coupling agent, uses the modified attapulgite powder as a template agent of hollow polymer microspheres, and guides emulsion polymerization to form a hollow structure; the hollow polymer microspheres of the application are introduced into a copper-clad plate resin system, which endows the resin system with large porosity, significantly reduces the dielectric constant and dielectric loss of the copper-clad plate through the hollow structure and mesoporous wall, and has excellent structural stability and is not prone to "ball breaking", thereby improving the compression resistance of the copper-clad plate; the modified attapulgite powder as the template agent can effectively control the structure of the hollow polymer microspheres, so that the hollow polymer microspheres have good compatibility with the copper-clad plate resin system, reduce interface defects, and make the copper-clad plate have excellent mechanical properties; the attapulgite powder is a natural mineral, which meets the development trend of green materials. BRIEF DESCRIPTION OF DRAWINGS
[0025] Figure 1 Scanning electron micrograph of the hollow polymer microspheres prepared in Example 1. DETAILED DESCRIPTION
[0026] The present application provides a preparation method of hollow polymer microspheres, comprising the following steps:
[0027] 1) mixing modified attapulgite powder, cyanate ester resin, initiator and solvent to obtain a mixed emulsion;
[0028] 2) performing emulsion polymerization reaction on the mixed emulsion to obtain polymer microspheres;
[0029] 3) performing acid washing on the polymer microspheres to obtain hollow polymer microspheres.
[0030] In the present application, the modified attapulgite powder in step 1) is preferably silane coupling agent modified attapulgite powder.
[0031] The preparation method of the silane coupling agent modified attapulgite powder preferably comprises: calcining attapulgite powder, and adding a silane coupling agent to the calcined attapulgite powder for modification. The modification of the silane coupling agent enables the attapulgite powder to be grafted with the silane coupling agent on the surface, thereby enhancing the bonding force between the attapulgite powder and the polymer.
[0032] In the present application, the particle size of the attapulgite powder is preferably 5-30 μm, further preferably 10-25 μm, and more preferably 15-20 μm.
[0033] In the present application, the attapulgite powder is preferably first subjected to acid washing, and then subjected to calcination and modification. The reagent used for acid washing of the attapulgite powder is preferably hydrochloric acid or nitric acid, and the mass fraction of the hydrochloric acid or nitric acid is independently preferably 0.5-2%, further preferably 1-1.5%, and more preferably 3.5 h. The acid washing of the attapulgite powder can remove surface impurities and improve the dispersibility of the attapulgite powder.
[0034] In the present application, the calcination temperature is preferably 500-800℃, further preferably 550-700℃, and more preferably 600-650℃; the calcination time is preferably 5-8 h, further preferably 6-7 h; and the temperature rising rate for rising to the calcination temperature is preferably 1-3℃ / min, further preferably 1.5-2.5℃ / min, and more preferably 2℃ / min. The calcination process enables the attapulgite powder to form a porous structure on the surface, thereby improving the stability of the attapulgite powder as a template agent.
[0035] In the present application, the mass of the silane coupling agent is preferably 0.1-1% of the mass of the attapulgite powder, further preferably 0.3-0.8%, and more preferably 0.5%.
[0036] The modification is preferably stirring modification, the temperature of the stirring modification is preferably 80-100 DEG C, further preferably 85-95 DEG C, more preferably 90 DEG C, the rotating speed of the stirring modification is preferably 800-1500 rpm, further preferably 1000-1300 rpm, more preferably 1100-1200 rpm, the time of the stirring modification is preferably 1-5 h, further preferably 2-4 h, more preferably 3 h.
[0037] In the application, the silane coupling agent is preferably silane coupling agent KH550 and / or silane coupling agent KH560.
[0038] In the application, the mass of the modified palygorskite powder in step 1) is preferably 10-25% of the mass of the mixed emulsion, further preferably 13-21%, more preferably 15-18%, the mass of the cyanate ester resin is preferably 50-70% of the mass of the mixed emulsion, further preferably 55-65%, more preferably 60%, the mass of the initiator is preferably 0.1-0.5% of the mass of the cyanate ester resin, further preferably 0.2-0.4%, more preferably 0.3%.
[0039] In the application, the cyanate ester resin preferably comprises one or more of bisphenol A type cyanate ester resin, bisphenol F type cyanate ester resin, bisphenol M type cyanate ester resin and dicyclopentadiene type cyanate ester resin.
[0040] The initiator preferably comprises one or more of ammonium persulfate, dibenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, cumene hydroperoxide and azobisisobutyronitrile.
[0041] The solvent preferably comprises one or more of dimethyl sulfoxide, N,N-dimethylformamide and N,N-dimethylacetamide.
[0042] In the application, the temperature of the emulsion polymerization reaction in step 2) is preferably 60-80 DEG C, further preferably 65-75 DEG C, more preferably 70 DEG C, the time of the emulsion polymerization reaction is preferably 2-4 h, further preferably 2.5-3.5 h, more preferably 3 h.
[0043] In the application, the reagent used in the acid washing in step 3) is preferably hydrochloric acid or nitric acid, and the mass fraction of the hydrochloric acid or nitric acid is independently preferably 0.5-2%, further preferably 1-1.5%.
[0044] The time of the acid washing is preferably 1-5 h, further preferably 2-4 h, more preferably 3 h.
[0045] In the application, after the acid washing in step 3), centrifugation, washing and drying are preferably sequentially performed to obtain the hollow polymer microspheres.
[0046] The rotation speed of the centrifugation is preferably 500-1000 rpm, further preferably 600-900 rpm, and more preferably 700-800 rpm; and the centrifugation time is preferably 1-5 h, further preferably 2-4 h, and more preferably 3 h.
[0047] The reagent used in the washing is preferably water, and the washing is preferably neutral.
[0048] The drying temperature is preferably 90-110℃, and further preferably 100℃; and the drying time is preferably 5-10 h, further preferably 6-9 h, and more preferably 7-8 h.
[0049] The application also provides the hollow polymer microspheres prepared by the preparation method.
[0050] The application also provides the application of the hollow polymer microspheres in copper-clad plates, wherein the hollow polymer microspheres are added into a copper-clad plate resin system.
[0051] In the application, the copper-clad plate resin system preferably comprises an epoxy resin, a dicyandiamide curing agent, a promoter and a solvent I.
[0052] The mass ratio of the hollow polymer microspheres to the epoxy resin is preferably 10-20:100, further preferably 12-18:100, and more preferably 15:100.
[0053] In the application, the mass ratio of the dicyandiamide curing agent to the epoxy resin is preferably 5-10:100, further preferably 6-9:100, and more preferably 7-8:100.
[0054] The mass ratio of the promoter to the epoxy resin is preferably 0.1-1:100, further preferably 0.2-0.8:100, and more preferably 0.5-0.6:100.
[0055] The mass ratio of the solvent I to the epoxy resin is preferably 80-120:100, further preferably 90-110:100, and more preferably 100:100.
[0056] In the application, the epoxy resin preferably comprises one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin and cyclopentadiene epoxy resin.
[0057] The promoter is preferably 2-ethyl-4-methylimidazole, and the solvent I is preferably N,N-dimethylformamide.
[0058] In the present application, the preparation method of the copper-clad plate preferably comprises: adding the hollow polymer microspheres into a copper-clad plate resin system to form a resin glue solution, then immersing a quartz cloth into the resin glue solution and taking it out to obtain a prepreg; laminating copper foils on both sides of the prepreg and performing hot-pressing molding.
[0059] In the present application, the thickness of the quartz cloth is preferably 0.1-0.2 mm, and further preferably 0.15 mm; the thickness of the copper foil is preferably 0.05-0.2 mm, and further preferably 0.1-0.15 mm.
[0060] In the present application, the temperature of the hot-pressing molding is preferably 150-180℃, and further preferably 160-170℃; the pressure of the hot-pressing molding is preferably 2-10 MPa, and further preferably 3-8 MPa, and more preferably 5-6 MPa; the time of the hot-pressing molding is preferably 2-4 h, and further preferably 2.5-3.5 h, and more preferably 3 h.
[0061] The technical solutions provided by the present application will be described in detail below in combination with examples, but they should not be understood as limiting the scope of protection of the present application.
[0062] The attapulgite powder used in the examples and comparative examples of the present application is purchased from Jiangsu Huixin Attapulgite Co., Ltd.
[0063] Example 1
[0064] The attapulgite powder with a particle size of 30 μm is pickled with 1% hydrochloric acid for 3 h, then the calcination furnace is heated to 600℃ at a rate of 2℃ / min, and the calcination is carried out at 600℃ for 8 h. After the calcination is completed, the temperature is naturally cooled to room temperature, and the silane coupling agent KH550 is added to the calcined attapulgite powder at 80℃, and the stirring modification is carried out at a speed of 1200 rpm for 3 h to obtain modified attapulgite powder. The mass of the silane coupling agent KH550 is 1% of the mass of the attapulgite powder.
[0065] The modified attapulgite powder, bisphenol A cyanate resin, ammonium persulfate and dimethyl sulfoxide are mixed to obtain a mixed emulsion. The mass of the modified attapulgite powder is 15% of the mass of the mixed emulsion, the mass of the bisphenol A cyanate resin is 60% of the mass of the mixed emulsion, and the mass of the ammonium persulfate is 0.3% of the mass of the bisphenol A cyanate resin. The mixed emulsion is subjected to emulsion polymerization reaction at 60℃ for 3 h. After the reaction is completed, the solid product is filtered, pickled with 1% hydrochloric acid for 2 h, and then centrifuged at a speed of 700 rpm for 3 h. The product after centrifugation is washed with deionized water until the washing liquid is neutral, and finally dried at 100℃ for 5 h to obtain hollow polymer microspheres.
[0066] Figure 1A scanning electron micrograph of the hollow polymer microspheres prepared in Example 1. The hollow polymer microspheres were prepared according to the following procedure. Figure 1 As can be seen, the particle size of the hollow polymer microspheres is in the range of 20-30 μm, and most of the hollow polymer microspheres are regular in shape.
[0067] Example 2
[0068] The attapulgite powder having a particle size of 25 μm was pickled with 1.5% by mass nitric acid for 5 h, and then placed in a calcination furnace, which was heated to 700°C at a rate of 1°C / min and calcined at 700°C for 6 h. After calcination, the attapulgite powder was naturally cooled to room temperature, and the silane coupling agent KH560 was added to the calcined attapulgite powder at 90°C, and stirred at a rate of 1500 rpm for 1 h to obtain modified attapulgite powder. The mass of the silane coupling agent KH560 was 0.1% of the mass of the attapulgite powder.
[0069] The modified attapulgite powder, bisphenol F cyanate resin, ammonium persulfate, and dimethyl sulfoxide were mixed to obtain a mixed emulsion. The mass of the modified attapulgite powder was 25% of the mass of the mixed emulsion, the mass of the bisphenol F cyanate resin was 65% of the mass of the mixed emulsion, and the mass of the ammonium persulfate was 0.2% of the mass of the bisphenol F cyanate resin. The mixed emulsion was subjected to emulsion polymerization at 70°C for 2.5 h. After the reaction was completed, the solid product was filtered, pickled with 1.5% by mass nitric acid for 1 h, and then centrifuged at a rate of 1000 rpm for 1 h. The centrifuged product was washed with deionized water until the washing liquid was neutral, and finally dried at 100°C for 7 h to obtain hollow polymer microspheres.
[0070] Example 3
[0071] The attapulgite powder having a particle size of 20 μm was pickled with 2% by mass hydrochloric acid for 2 h, and then placed in a calcination furnace, which was heated to 550°C at a rate of 3°C / min and calcined at 550°C for 5 h. After calcination, the attapulgite powder was naturally cooled to room temperature, and the silane coupling agent KH550 and the silane coupling agent KH560 were added to the calcined attapulgite powder at 100°C, and stirred at a rate of 800 rpm for 5 h to obtain modified attapulgite powder. The total mass of the silane coupling agent KH550 and the silane coupling agent KH560 was 0.5% of the mass of the attapulgite powder, and the mass ratio of the silane coupling agent KH550 to the silane coupling agent KH560 was 1:2.
[0072] The modified attapulgite powder, dicyclopentadiene cyanate ester resin, ammonium persulfate and dimethyl sulfoxide are mixed to obtain a mixed emulsion. The mass of the modified attapulgite powder is 10% of the mass of the mixed emulsion, the mass of the dicyclopentadiene cyanate ester resin is 70% of the mass of the mixed emulsion, and the mass of the ammonium persulfate is 0.1% of the mass of the dicyclopentadiene cyanate ester resin. The mixed emulsion is subjected to emulsion polymerization at 80℃ for 2h. After the reaction is completed, the solid product is obtained by filtration, and the solid product is subjected to acid pickling with 1% hydrochloric acid for 5h, and then centrifuged at a speed of 500rpm for 5h. The product after centrifugation is washed with deionized water until the washing liquid is neutral, and finally dried at 100℃ for 10h to obtain hollow polymer microspheres.
[0073] Comparative Example 1
[0074] The modified attapulgite powder in Example 2 is replaced with modified calcium carbonate powder, and the rest is the same as Example 2.
[0075] The preparation method of the modified calcium carbonate powder is as follows: the calcium carbonate powder with a particle size of 25μm is subjected to acid pickling with 1.5% nitric acid for 5h. Then the calcination furnace is heated to 550℃ at a rate of 1℃ / min, and the calcination furnace is kept at 550℃ for 6h. After calcination is completed, it is naturally cooled to room temperature. The silane coupling agent KH560 is added to the calcined calcium carbonate powder at 90℃, and the stirring modification is carried out at a speed of 1500rpm for 1h to obtain the modified calcium carbonate powder. The mass of the silane coupling agent KH560 is 0.1% of the mass of the calcium carbonate powder.
[0076] Comparative Example 2
[0077] The dicyclopentadiene cyanate ester resin in Example 1 is replaced with bisphenol A type epoxy resin, and the rest is the same as Example 1.
[0078] Application Example 1
[0079] 10 parts of the hollow polymer microspheres prepared in Example 1 are added to the copper-clad plate resin system to form a resin glue solution. The copper-clad plate resin system comprises 100 parts of bisphenol A type epoxy resin, 7 parts of
[0080] dicyandiamide curing agent, 0.5 parts of 2-ethyl-4-methyl imidazole, and 80 parts of N,N-dimethylformamide. A quartz cloth with a size of 1m×1m×0.1mm is immersed in the resin glue solution by a transmission device to form a semi-cured sheet (the transmission speed of the transmission device is 5m / min). The copper foil with a size of 1m×1m×0.05mm is laminated on both sides of the semi-cured sheet, and then hot-pressed at 160℃ and 5MPa for 3h to obtain a copper-clad plate.
[0081] Application Example 2
[0082] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 2, and the rest is the same as in Application Example 1.
[0083] Application Example 3
[0084] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 3, and the rest is the same as in Application Example 1.
[0085] Application Example 4
[0086] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 2, and the rest is the same as in Application Example 1.
[0087] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 2, and the rest is the same as in Application Example 1.
[0088] Application Example 5
[0089] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 2, and the rest is the same as in Application Example 1.
[0090] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 2, and the rest is the same as in Application Example 1.
[0091] Application Comparative Example 1
[0092] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 2, and the rest is the same as in Application Example 1.
[0093] Application Comparative Example 2
[0094] The hollow polymeric microspheres in Application Example 1 are replaced with the hollow polymeric microspheres prepared in Example 2, and the rest is the same as in Application Example 1.
[0095] Application Comparative Example 3
[0096] The hollow polymer microspheres in application example 1 were replaced with polymethyl methacrylate hollow microspheres (purchased from Macklin Reagent), and the others were the same as in application example 1.
[0097] Application Comparative Example 4
[0098] The hollow polymer microspheres in application example 1 were omitted, and the others were the same as in application example 1.
[0099] The copper-clad plates prepared in application examples 1-5 and application comparative examples 1-4 were respectively subjected to performance testing. The dielectric constant and dielectric loss at 1 MHz were determined according to GB / T31838.6-2021, and the bending strength was determined according to GB / T 1449-2005. The test results are shown in Table 1.
[0100] Table 1: Performance test results of copper-clad plate
[0101] Dielectric constant / F / m Dielectric loss Bending strength MPa ]] Application Example 1 2.8 0.012 230 Application Example 2 2.75 0.01 238 Application Example 3 2.68 0.009 242 Application Example 4 2.7 0.008 246 Application Example 5 2.65 0.007 256 Application Comparative Example 1 3.0 0.014 210 Application Comparative Example 2 3.1 0.015 205 Application Comparative Example 3 3.2 0.016 195 Application Comparative Example 4 3.5 0.018 180
[0102] As can be seen from Table 1, the dielectric constant and dielectric loss of the copper-clad plates of application examples 1-5 are lower than those of application comparative examples 1-4, and the mechanical properties are higher than those of application comparative examples 1-4. The results show that the hollow polymer microspheres prepared by emulsion polymerization using the silane coupling agent modified modified attapulgite powder as a template agent and used as a low dielectric filler of the copper-clad plate can effectively reduce the dielectric constant and dielectric loss of the copper-clad plate, while improving the mechanical properties of the copper-clad plate.
[0103] The above description is only the preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should be considered as the protection scope of the present application.
Claims
1. A method for preparing hollow polymer microspheres, characterized in that: The following steps are included: 1) mixing the modified attapulgite powder, cyanate resin, initiator and solvent to obtain a mixed emulsion; 2) subjecting the mixed emulsion to emulsion polymerization to obtain polymer microspheres; 3) The polymer microspheres are acid-washed to obtain hollow polymer microspheres.
2. The preparation method according to claim 1, characterized in that Step 1) The modified attapulgite powder is silane coupling agent modified attapulgite powder; The preparation method of silane coupling agent modified attapulgite powder comprises: calcining the attapulgite powder, and adding a silane coupling agent to the calcined attapulgite powder for modification.
3. The preparation method according to claim 2, characterized in that The calcination temperature is 500-800° C., the calcination time is 5-8 hours, and the heating rate to the calcination temperature is 1-3° C. / min.
4. The preparation method according to claim 2 or 3, characterized in that The mass of the silane coupling agent is 0.1 to 1% of the mass of the attapulgite powder; The modification is stirring modification, the stirring modification temperature is 80-100° C., the stirring modification speed is 800-1500 rpm, and the stirring modification time is 1-5 hours.
5. The preparation method according to claim 4, characterized in that In step 1), the mass of the modified attapulgite powder is 10-25% of the mass of the mixed emulsion, the mass of the cyanate ester resin is 50-70% of the mass of the mixed emulsion, and the mass of the initiator is 0.1-0.5% of the mass of the cyanate ester resin.
6. The preparation method according to claim 5, characterized in that Step 2) The temperature of the emulsion polymerization reaction is 60-80° C., and the time of the emulsion polymerization reaction is 2-4 hours.
7. The preparation method according to claim 6, characterized in that Step 3) The pickling agent used is hydrochloric acid or nitric acid, and the mass fraction of the hydrochloric acid or nitric acid is independently 0.5-2%; The pickling time is 1 to 5 hours.
8. Hollow polymer microspheres prepared by the preparation method according to any one of claims 1 to 7.
9. Use of the hollow polymer microspheres according to claim 8 in copper clad laminates, characterized in that: The hollow polymer microspheres are added into a copper clad laminate resin system.
10. The use according to claim 9, characterized in that The copper clad laminate resin system comprises epoxy resin, dicyandiamide curing agent, accelerator and solvent I; The mass ratio of the hollow polymer microspheres to the epoxy resin is 10-20:100.