Polystyrene composite board and preparation method and application thereof

Abstract

The present application relates to a kind of polystyrene composite board and its preparation method and application.The preparation method of the polystyrene composite board includes the following steps:S1.melt extrusion, granulation, obtain polystyrene composite material including dielectric constant enhancer and polystyrene resin;S2.pulverization is obtained polystyrene composite material powder;S3.polystyrene composite material powder is mixed with mixed solution, swells, and is made into mixture;The mixed solution includes styrene monomer, crosslinking agent and initiator;S4.the mixture is heat-pressed, and the polystyrene composite board is obtained.The polystyrene composite board prepared by the preparation method has high dielectric constant, good toughness and heat resistance, can well meet the requirements of subsequent mechanical processing of board and is very suitable for preparing electronic communication device.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a polystyrene composite board, its preparation method, and its application. Background Technology

[0002] Polymer materials, with their advantages of low cost and ease of processing, are widely used in fields such as electronic communications, radio transmission, and microwave technology. In electronic communications, polymer materials are often first prepared into composite sheets, which are then machined into various irregularly shaped devices. These are suitable for manufacturing complex-shaped filters, couplers, and antennas in high-frequency circuits. These composite sheets need to possess high dielectric constant and low dielectric loss characteristics. High dielectric constant facilitates device miniaturization, while low dielectric loss is a prerequisite for low-loss communication transmission. Most polymer materials have relatively low dielectric constants, and doping with inorganic fillers with high dielectric constants is a common method to improve the dielectric constant.

[0003] Polystyrene is a low-cost polymer material with excellent processability. It has a low dielectric constant and dielectric loss and is very stable in the high-frequency range. Its dielectric constant can be improved by adding doped inorganic fillers such as barium titanate and magnesium titanate.

[0004] Common methods for preparing inorganic filler-polystyrene composite boards include solution blending and mechanical blending. Solution blending requires dispersing inorganic fillers in a polystyrene solution. Due to the high density of inorganic fillers, they are prone to sedimentation during molding, resulting in uneven distribution of inorganic fillers in the thickness direction. Consequently, the improvement in the dielectric constant of the product is not significant. Currently, solution blending is rarely used to prepare polystyrene composite boards and is more often used to prepare polystyrene composite films with small thicknesses (micrometer level).

[0005] In the mechanical blending method, inorganic fillers are dry-blended or melt-blended with polystyrene, followed by hot pressing to obtain composite boards. This method overcomes the problem of inorganic filler sedimentation in the solution blending method. However, the high brittleness and low glass transition temperature of polystyrene result in poor mechanical properties and heat resistance of polystyrene composite boards, which makes subsequent machining difficult and thus limits their application range.

[0006] Furthermore, although the dielectric constant of polystyrene composite boards obtained by mechanical blending is higher than that obtained by solution blending, the dielectric constant of polystyrene composite boards still needs to be further improved due to the limited compatibility between polystyrene and inorganic fillers, in order to meet the higher requirements for material performance in the current electronic communication field.

[0007] Therefore, there is an urgent need to develop a polystyrene composite board with high dielectric constant, good mechanical properties and good heat resistance. Summary of the Invention

[0008] The primary objective of this invention is to overcome the problems of existing polystyrene composite boards, such as the need to improve dielectric constant, poor mechanical properties, and poor heat resistance, and to provide a method for preparing polystyrene composite boards.

[0009] A further objective of this invention is to provide a polystyrene composite board.

[0010] A further object of the present invention is to provide the application of the above-mentioned polystyrene composite material in the preparation of energy storage capacitors, filters for high-frequency circuits, couplers for high-frequency circuits, or antennas for high-frequency circuits.

[0011] The above-mentioned objective of the present invention is achieved through the following technical solution: A method for preparing a polystyrene composite board includes the following steps: S1. The components including dielectric constant reinforcing agent and polystyrene resin are melt-extruded and granulated to obtain polystyrene composite material; S2. Grind the polystyrene composite material to obtain polystyrene composite material powder; S3. The polystyrene composite material powder is mixed with a mixture and swollen to obtain a mixture; the mixture includes styrene monomer, crosslinking agent and initiator; S4. The mixture is hot-pressed to obtain the polystyrene composite board.

[0012] This invention first melts, granulates, and grinds a dielectric constant enhancer and polystyrene resin to obtain polystyrene composite powder. After the polystyrene composite powder swells with styrene monomers and crosslinking agents, the resulting mixture can undergo in-situ polymerization and crosslinking during hot pressing, effectively preventing the sedimentation of the dielectric constant enhancer during hot pressing. This forms a continuous network structure of crosslinked polystyrene that encapsulates the dielectric constant enhancer / polystyrene system. The dielectric constant enhancer in this system is uniformly dispersed, resulting in a significant increase in the dielectric constant of the polystyrene composite board. Furthermore, the continuous network structure also improves the toughness and heat resistance of the polystyrene composite board, which can well meet the requirements of subsequent machining of the board and is very suitable for the preparation of electronic communication devices.

[0013] In this invention, styrene monomer refers to a monomer containing one vinyl group, namely styrene.

[0014] Preferably, in step S1, the dielectric constant enhancer is at least one of niobium pentoxide, cobalt tetroxide, barium titanate, zirconium oxide, titanium dioxide, strontium titanate, or magnesium titanate.

[0015] Preferably, in step S1, the average particle size of the dielectric constant enhancer is 50~300nm.

[0016] Preferably, in step S1, the dielectric constant enhancer is a dielectric constant enhancer modified with a silane coupling agent.

[0017] More preferably, the silane coupling agent is one of octadecyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. The antioxidant is at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], tris[2,4-di-tert-butylphenyl]phosphite, and octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate.

[0018] More preferably, a dielectric constant enhancer modified with a silane coupling agent is obtained by a wet modification method.

[0019] Further preferably, the wet modification process is as follows: the dielectric constant enhancer is mixed with the silane coupling agent solution, stirred at room temperature for 2-3 hours, filtered and dried to obtain the silane coupling agent modified dielectric constant enhancer.

[0020] More preferably, the mass ratio of the dielectric constant enhancer to the silane coupling agent in the silane coupling agent solution is 1:0.1~0.25.

[0021] Preferably, in step S1, the mass ratio of the dielectric constant reinforcing agent to the polystyrene resin is 20~80:20~80.

[0022] More preferably, in step S1, the mass ratio of the dielectric constant reinforcing agent to the polystyrene resin is 50~70:30~50.

[0023] Preferably, in step S1, the melt index of the polystyrene resin measured at 200℃ / 5kg is 5~20g / 10min.

[0024] Preferably, in step S1, the component further includes an antioxidant.

[0025] More preferably, the mass ratio of the polystyrene resin to the antioxidant is 20~80:0.1~0.3.

[0026] Preferably, in step S1, the temperature of the melt extrusion is 170~200℃, and the screw speed of the extruder for melt extrusion is 150~300rpm.

[0027] Preferably, in step S2, the grinding process is as follows: add liquid nitrogen to submerge the polystyrene composite material, freeze for 10-15 minutes, and then grind at a speed of 500-2000 rpm for 10-60 minutes.

[0028] Preferably, in step S2, after grinding, a sieving step is further included; the sieving results in the polystyrene composite powder being at least one of 100-mesh polystyrene composite powder or 400-mesh polystyrene composite powder.

[0029] 100-mesh polystyrene composite powder refers to polystyrene composite powder that passes through an 80-mesh sieve but not a 100-mesh sieve; 400-mesh polystyrene composite powder refers to polystyrene composite powder that passes through a 325-mesh sieve but not a 400-mesh sieve.

[0030] More preferably, the polystyrene composite powder comprises 100-mesh polystyrene composite powder and 400-mesh polystyrene composite powder in a mass ratio of 5~7:3~5.

[0031] After grinding, the mixture is sieved, and two different mesh sizes of polystyrene composite powder are used in subsequent steps. The size effect further improves the dispersion uniformity of the system components, resulting in polystyrene composite boards with higher dielectric constant and glass transition temperature.

[0032] Preferably, in step S3, the mass ratio of the polystyrene composite material powder to the mixture is 80~90:10~20.

[0033] More preferably, in step S3, the mass ratio of the polystyrene composite material powder to the mixture is 85~90:10~15.

[0034] Preferably, in step S3, the mixing and swelling process is as follows: first stir for 15-30 minutes, then let stand for 5-10 hours.

[0035] More preferably, during the settling period, the mixture is stirred for 5 to 10 minutes every 1 to 2 hours.

[0036] Preferably, in step S3, the mass ratio of the styrene monomer, crosslinking agent, and initiator is 95~99:0.5~3:0.05~1.

[0037] More preferably, in step S3, the mass ratio of the styrene monomer, crosslinking agent, and initiator is 95~99:2.5~3:0.5~1.

[0038] In this invention, a crosslinking agent refers to a monomer containing two or more vinyl groups.

[0039] Preferably, in step S3, the crosslinking agent is divinylbenzene.

[0040] More preferably, the divinylbenzene is at least one of p-divinylbenzene, m-divinylbenzene, or o-divinylbenzene.

[0041] Preferably, in step S3, the initiator is at least one of azobisisobutyronitrile or benzoyl peroxide.

[0042] Preferably, in step S3, the preparation process of the mixture is as follows: styrene monomer, crosslinking agent and initiator are stirred for 15 to 60 minutes at a speed of 50 to 200 rpm and a temperature of 15 to 25°C.

[0043] Preferably, in step S4, before the hot pressing, the step further includes adding the slurry into the mold and vacuuming to remove bubbles.

[0044] Preferably, in step S4, the hot pressing conditions are: time of 50~240h, temperature of 45~120℃, and pressure of 1~10MPa.

[0045] More preferably, in step S4, the hot pressing conditions are: first, maintaining at 45~55℃ and 1~3MPa for 90~120h, and then maintaining at 90~120℃ and 8~11MPa for 1~10h.

[0046] Preferably, the thickness of the polystyrene composite board is 8~20mm.

[0047] A polystyrene composite board is prepared by the above-described method.

[0048] The application of the aforementioned polystyrene composite sheet in the preparation of energy storage capacitors, filters for high-frequency circuits, couplers for high-frequency circuits, or antennas for high-frequency circuits is also within the scope of protection of this invention.

[0049] Compared with the prior art, the beneficial effects of the present invention are: The polystyrene composite board prepared by the method of the present invention has high dielectric constant, good toughness and heat resistance, which can well meet the requirements of subsequent machining of the board and is very suitable for the preparation of electronic communication devices. Detailed Implementation

[0050] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0051] Example 1 This embodiment provides a method for preparing polystyrene composite boards, including the following steps: (1) Barium titanate with an average particle size of 100 nm and 2 wt% γ-aminopropyltriethoxysilane in an ethanol / water solution (the mass ratio of silane, ethanol and water is 2:70:28) were mixed evenly, with the mass ratio of barium titanate to γ-aminopropyltriethoxysilane being 1:0.1. The mixture was stirred at room temperature for 3 hours, then filtered, and dried in a vacuum oven at 100 °C for 6 hours to obtain a surface-functionalized dielectric constant enhancer. 50 parts by weight of the surface-functionalized dielectric constant enhancer, 50 parts by weight of polystyrene resin (Yanshan Petrochemical 666D, melt index of 8.0 g / 10 min at 200 °C / 5 kg), 0.2 parts by weight of antioxidant 1010, and 0.1 parts by weight of antioxidant 168 were mixed evenly in a high-speed mixer, then melted and extruded in a twin-screw extruder, water-cooled and pelletized, and dried at 80 °C for 4 hours to obtain a polystyrene composite material. The temperatures of the melting zones in the twin-screw extruder are 170℃, 180℃, 190℃, 200℃, 205℃, and 200℃, respectively, and the screw speed is 200 rpm. (2) The polystyrene composite material was added to a ball mill jar, and liquid nitrogen was added until the polystyrene composite material was submerged. After cooling for 15 minutes, it was ball milled at 1000 rpm for 30 minutes to obtain polystyrene composite material powder. The polystyrene composite material powder was sieved using a vibrating screen to obtain 100-mesh (passing through an 80-mesh sieve but not passing through a 100-mesh sieve) polystyrene composite material powder and 400-mesh (passing through a 325-mesh sieve but not passing through a 400-mesh sieve) polystyrene composite material powder. (3) Weigh 100-mesh polystyrene composite powder and 400-mesh polystyrene composite powder with a mass ratio of 6:4, mix them evenly in a high-speed mixer to obtain a mixed powder for later use. Add styrene, divinylbenzene (p-divinylbenzene), and azobisisobutyronitrile with a mass ratio of 97:2.5:0.5 into a jacketed dispersion vessel and stir for 20 min at a stirring speed of 50 rpm and a stirring temperature of 20 °C to obtain a mixed liquid. Add the mixed liquid to the above mixed powder with a mass ratio of mixed powder to mixed liquid of 90:10, continue stirring for 30 min, and then let it stand for 6 h. During the standing period, stir for 5 min every 1 h to ensure that the liquid material is fully swollen and dispersed in the mixed powder to obtain a mixture. (4) Add the above mixture into the mold, vacuum degas it, close the mold on a flat vulcanizing machine, first hot press at 50℃ and 2MPa for 100h, then hot press at 100℃ and 10MPa for 2h. After natural cooling, demold to obtain a polystyrene composite board with a thickness of 10mm.

[0052] Example 2 This embodiment provides a method for preparing polystyrene composite boards, which differs from Embodiment 1 in that: In step (1), the amount of surface functionalized dielectric constant enhancer is adjusted to 70 parts by weight, and the amount of polystyrene resin is adjusted to 30 parts by weight. In step (3), the mass ratio of 100-mesh polystyrene composite powder to 400-mesh polystyrene composite powder is adjusted to 5:5.

[0053] Example 3 This embodiment provides a method for preparing polystyrene composite boards, which differs from Embodiment 1 in that: In step (1), the preparation process of the surface functionalized dielectric constant enhancer is changed to: barium titanate with an average particle size of 100 nm and niobium pentoxide with an average particle size of 100 nm are mixed at a mass ratio of 1:1, and then mixed evenly with 5 wt% ethanol / water solution of octadecyltrimethoxysilane (the mass ratio of silane, ethanol and water is 5:70:25). The mass ratio of dielectric enhancer (barium titanate and niobium pentoxide) to octadecyltrimethoxysilane is 1:0.25. The mixture is stirred at room temperature for 2 hours, then filtered and dried in a vacuum oven at 100°C for 6 hours. In step (3), the mass ratio of 100-mesh polystyrene composite powder to 400-mesh polystyrene composite powder is adjusted to 7:3; the mass ratio of mixed powder to mixed liquid is 85:15.

[0054] Example 4 This embodiment provides a method for preparing polystyrene composite boards, which differs from Embodiment 1 in that: Step (3) is modified as follows: Styrene, divinylbenzene, and azobisisobutyronitrile (DIOB) in a mass ratio of 97:2.5:0.5 are added to a jacketed dispersion vessel and stirred for 20 minutes at a stirring speed of 50 rpm and a stirring temperature of 20°C to obtain a mixture. The mixture is then added to 100-mesh polystyrene composite powder at a mass ratio of 90:10. Stirring is continued for 30 minutes, followed by standing for 6 hours. During the standing period, the mixture is stirred for 5 minutes every hour to ensure that the liquid material is fully swollen and dispersed in the mixed powder to obtain the final mixture.

[0055] Example 5 This embodiment provides a method for preparing polystyrene composite boards, which differs from Embodiment 1 in that: Step (3) is modified as follows: Styrene, divinylbenzene, and azobisisobutyronitrile (DIOB) in a mass ratio of 97:2.5:0.5 are added to a jacketed dispersion vessel and stirred for 20 minutes at a stirring speed of 50 rpm and a stirring temperature of 20°C to obtain a mixture. The mixture is then added to 400-mesh polystyrene composite powder at a mass ratio of 90:10. Stirring continues for 30 minutes, followed by standing for 6 hours. During the standing period, the mixture is stirred for 5 minutes every hour to ensure that the liquid material is fully swollen and dispersed in the mixed powder to obtain the final mixture.

[0056] Example 6 This embodiment provides a method for preparing polystyrene composite boards, which differs from Embodiment 1 in that: In step (2), no screening is performed.

[0057] In step (3), unsieved polystyrene composite powder is used instead of mixed powder.

[0058] Comparative Example 1 This comparative example provides a method for preparing a polystyrene composite board, comprising the following steps: (1) Same as step (1) of Example 1; (2) Same as step (2) in Example 1; (3) Weigh 100-mesh polystyrene composite powder and 400-mesh polystyrene composite powder in a mass ratio of 6:4, mix them evenly in a high-speed mixer to obtain a mixed powder. Add the powder to a mold, vacuum degas it, close the mold on a flat vulcanizing machine, and hot press it at 200℃ and 15MPa for 30min. After natural cooling, demold to obtain a polystyrene composite board with a thickness of 10mm.

[0059] Comparative Example 2 This comparative example provides a method for preparing a polystyrene composite board, comprising the following steps: (1) Barium titanate with an average particle size of 100 nm and 2 wt% of γ-aminopropyltriethoxysilane in an ethanol / water solution (the mass ratio of silane, ethanol and water is 2:70:28) were mixed evenly, and the mass ratio of barium titanate to γ-aminopropyltriethoxysilane was 1:0.1. The mixture was stirred at room temperature for 3 hours, then filtered, and dried in a vacuum oven at 100 °C for 6 hours to obtain a surface-functionalized dielectric constant enhancer. 50 parts by weight of the surface-functionalized dielectric constant enhancer, 50 parts by weight of polystyrene resin (Yanshan Petrochemical 666D, melt index of 8.0 g / 10 min at 200 °C / 5 kg), 0.2 parts by weight of antioxidant 1010 and 0.1 parts by weight of antioxidant 168 were mixed evenly in a high-speed mixer, then transferred to a ball mill jar, liquid nitrogen was added to submerge the solid, cooled for 15 min, and then ball-milled at 1000 rpm for 30 min to obtain powder. (2) Styrene, divinylbenzene, and azobisisobutyronitrile (DIOB) in a mass ratio of 97:2.5:0.5 were added to a jacketed dispersion vessel and stirred for 20 min at a stirring speed of 50 rpm and a stirring temperature of 20 °C to obtain a mixture. The mixture was then added to the powder in a mass ratio of 90:10, and stirring was continued for 30 min. The mixture was then allowed to stand for 6 h, with stirring for 5 min every 1 h during the standing period to obtain a final mixture. (3) Add the above mixture into the mold, vacuum degas it, close the mold on a flat vulcanizing machine, first hot press at 50℃ and 2MPa for 100h, and then hot press at 100℃ and 10MPa for 2h. After natural cooling, demold to obtain a polystyrene composite board with a thickness of 10mm.

[0060] Comparative Example 3 This comparative example provides a method for preparing a polystyrene composite board, which differs from Example 1 in that: In step (3), divinylbenzene is not added during the preparation of the mixture.

[0061] Performance testing The polystyrene composite boards prepared in Examples 1-6 and Comparative Examples 1-3 were polished and their dielectric constant (Dk) and dielectric loss (Df) were tested according to BS EN IEC62631-2-1-2018 standard at a test temperature of 23°C and a relative humidity of 50%RH. The polystyrene composite boards prepared in Examples 1-6 and Comparative Examples 1-3 were also cut into standard strips, and their mechanical properties were tested according to GB / T 1843-2008. The glass transition temperature was tested using a Waters differential scanning calorimeter (DSC). The test results are shown in Table 1 below.

[0062] Table 1

[0063] As can be seen from Table 1, The polystyrene composite boards in Examples 1-6 all have a dielectric constant of 5.61 or higher and an impact strength of 5.5 kJ / m. 2 The glass transition temperatures of the polystyrene composite sheets of the present invention are all above 104.7°C, indicating that the polystyrene composite sheets of the present invention possess high dielectric constant, good mechanical properties, and high glass transition temperature. Furthermore, the dielectric loss of the polystyrene composite sheets of the present invention remains at a low level.

[0064] Compared to Example 1, Comparative Example 1 did not mix the polystyrene composite powder with the styrene monomer mixture, but instead directly used the polystyrene composite powder to prepare the polystyrene composite board. The resulting polystyrene composite board had a low dielectric constant, poor impact strength, and low glass transition temperature.

[0065] Compared to Examples 1 and 6, Comparative Example 2 did not undergo melt extrusion, resulting in a polystyrene composite board with a low dielectric constant and poor impact strength.

[0066] Compared to Example 1, Comparative Example 3 did not add divinylbenzene in step (3), resulting in polystyrene composite boards with poor impact strength and low glass transition temperature.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a polystyrene composite board, characterized in that, Includes the following steps: S1. The components including dielectric constant reinforcing agent and polystyrene resin are melt-extruded and granulated to obtain polystyrene composite material; S2. Grind the polystyrene composite material to obtain polystyrene composite material powder; S3. The polystyrene composite material powder is mixed with a mixture and swollen to obtain a mixture; the mixture includes styrene monomer, crosslinking agent and initiator; S4. The mixture is hot-pressed to obtain the polystyrene composite board.

2. The preparation method according to claim 1, characterized in that, In step S1, the dielectric constant enhancer is at least one of niobium pentoxide, cobalt tetroxide, barium titanate, zirconium oxide, titanium dioxide, strontium titanate, or magnesium titanate.

3. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the dielectric constant reinforcing agent to polystyrene resin is 20~80:20~80.

4. The preparation method according to claim 1, characterized in that, In step S2, the grinding process is as follows: add liquid nitrogen to submerge the polystyrene composite material, freeze for 10-15 minutes, and then grind at a speed of 500-2000 rpm for 10-60 minutes.

5. The preparation method according to claim 1, characterized in that, In step S2, after grinding, a sieving step is also included; the sieving results in the polystyrene composite powder being at least one of 100-mesh polystyrene composite powder or 400-mesh polystyrene composite powder.

6. The preparation method according to claim 5, characterized in that, The polystyrene composite powder includes 100-mesh polystyrene composite powder and 400-mesh polystyrene composite powder in a mass ratio of 5~7:3~5.

7. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the polystyrene composite material powder to the mixture is 80~90:10~20.

8. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the styrene monomer, crosslinking agent, and initiator is 95~99:0.5~3:0.5~1.

9. A polystyrene composite board, characterized in that, It is prepared by any of the preparation methods described in claims 1 to 8.

10. The application of the polystyrene composite sheet of claim 9 in the preparation of energy storage capacitors, filters for high-frequency circuits, couplers for high-frequency circuits, or antennas for high-frequency circuits.

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