Flame-retardant PPS-based shielding film and preparation method thereof

Abstract

The invention relates to a flame-retardant PPS-based shielding film and a preparation method thereof, and belongs to the technical field of shielding film preparation. The PPS-based shielding film is prepared from the following raw materials in parts by weight: 80 to 100 parts of polyphenylene sulfide, 35 to 55 parts of functional toughening agent and 15 to 30 parts of modified carbon fiber, the functional toughening agent is generated by carrying out surface treatment reaction on magnetic silicon dioxide particles and a macromolecular silane coupling agent. According to the invention, the functional toughening agent is introduced into the PPS resin material, and the functional toughening agent is the magnetic mesoporous silica grafted with the polydimethylsiloxane chain on the surface, so that the toughness of the composite material is improved, and the battery shielding performance of the composite material is also improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of shielding film preparation, and in particular, relates to a flame-retardant PPS-based shielding film and a preparation method thereof. Background Art

[0002] Shielding films are widely used on the outer surfaces of various circuit boards in electronic devices to reduce electromagnetic noise from the circuit boards, improve the electromagnetic compatibility of electronic devices, and meet the growing functional diversification of electronic devices. Common existing shielding films include metal films (including single-layer and multi-layer metal films), nanocomposite films (metal films combined with nanomaterials (such as nanoparticles or nanofibers) to provide broad frequency shielding), and elastic polymer films (composed of elastic polymer materials with shielding properties, which can be flexibly applied to device surfaces of various shapes and sizes). Elastic polymer films have shown rapid growth in recent years due to their excellent processing properties. PPS-based shielding films, in particular, use polyphenylene sulfide (PPS) resin as their base resin. Due to PPS's excellent heat resistance and thermal stability, as well as its excellent corrosion and chemical resistance, very low dielectric constant, and excellent insulation properties in high-temperature and high-humidity environments, PPS-based shielding films have a very broad application prospect. However, the electromagnetic shielding performance of PPS-based films needs to be improved. Summary of the Invention

[0003] The object of the present invention is to provide a flame-retardant PPS-based shielding film and a preparation method thereof, so as to solve the problem that the existing PPS-based film has low shielding performance.

[0004] The first object of the present invention can be achieved by the following technical solutions:

[0005] A flame-retardant PPS-based shielding film comprises the following raw materials in parts by weight: 80-100 parts of polyphenylene sulfide, 35-55 parts of a functional toughening agent, and 15-30 parts of modified carbon fiber;

[0006] The functional toughening agent is produced by surface treatment reaction of magnetic silicon dioxide particles and macromolecular silane coupling agent.

[0007] Furthermore, the mass ratio of the magnetic silica particles to the macromolecular silane coupling agent is 10:3-4.

[0008] Furthermore, the surface treatment reaction temperature is 50-100° C., and the reaction time is 4-12 hours.

[0009] Furthermore, the surface treatment reaction occurs in the presence of a first organic solvent and water.

[0010] Preferably, the first organic solvent is ethanol.

[0011] Preferably, the volume ratio of ethanol to water is 7-9:1-3.

[0012] Furthermore, the magnetic silica particles are prepared by mixing amino-modified mesoporous silica with a solution containing an iron source, and then undergoing a hydrothermal reaction stage and a sintering reaction stage.

[0013] Furthermore, the temperature of the hydrothermal reaction stage is 75-100° C., and the reaction time is 6-12 hours.

[0014] Furthermore, the temperature of the sintering reaction stage is 550-700° C., and the reaction time is 4-12 hours.

[0015] Furthermore, the iron source is one of ferric chloride, ferric nitrate and ferric sulfate.

[0016] Furthermore, the macromolecular silane coupling agent is prepared by reacting bisamino-terminated polydimethylsiloxane and an epoxy silane coupling agent.

[0017] Furthermore, the molar ratio of the bisamino-terminated polydimethylsiloxane to the epoxy silane coupling agent is 1:1-2.

[0018] Furthermore, the relative molecular mass of the bis-amino-terminated polydimethylsiloxane is 2000-5000.

[0019] Furthermore, the modified carbon fiber is one of silane coupling agent modified carbon fiber and silver-plated carbon fiber.

[0020] Furthermore, the amino-modified mesoporous silica is prepared by hydrolysis reaction of ethyl orthosilicate and 3-aminopropyltriethoxysilane in an acidic emulsion.

[0021] Furthermore, the mass ratio of the ethyl orthosilicate to 3-aminopropyltriethoxysilane is 1-3:1.

[0022] Furthermore, the acidic emulsion is formed by mixing hydrochloric acid, water and a surfactant.

[0023] Furthermore, the pH of the acidic emulsion is 2-5, and the mass content of the surfactant in the acidic emulsion is 0.5-3%.

[0024] The second object of the present invention can be achieved by the following technical solutions:

[0025] A method for preparing a flame-retardant PPS-based shielding film comprises:

[0026] The polyphenylene sulfide, functional toughening agent and modified carbon fiber are blended, extruded, stretched and shaped to obtain a PPS-based shielding film.

[0027] Furthermore, the temperature of the blending extrusion is 270-320°C.

[0028] Furthermore, the stretching temperature is 90-125°C.

[0029] Beneficial effects of the present invention:

[0030] The flame-retardant PPS-based shielding film and preparation method thereof of the present invention introduce a functional toughening agent into the PPS resin material, wherein the functional toughening agent is a magnetic mesoporous silica with a polydimethylsiloxane chain grafted on the surface. The magnetic mesoporous silica is used as a rigid particle to exert rigid toughness, and the flexible polymer chain of the polydimethylsiloxane chain is used to exert flexible toughness, thereby improving the shortcoming of poor toughness of the PPS resin. Moreover, the magnetic mesoporous silica in the present invention is loaded with ferric oxide, and the electromagnetic shielding performance of the resulting material is improved by utilizing the ability of ferric oxide to absorb electromagnetic waves and convert them into thermal energy. Therefore, the introduction of the functional toughening agent not only improves the toughness of the composite material, but also improves the battery shielding performance of the composite material.

[0031] Most notably, ferric oxide is evenly dispersed in the PPS resin through mesoporous silica. The pores of the mesoporous silica provide a heat dissipation channel for the heat generated by the electromagnetic waves absorbed by the ferric oxide, thereby improving the heat dissipation performance of the resulting film and improving the heat dissipation of the film to the circuit substrate.

[0032] In addition, the flame retardant properties of the final shielding film are improved by utilizing the flame retardant properties of mesoporous silica and polydimethylsiloxane chains. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0034] Example 1

[0035] Preparation of magnetic silica particles:

[0036] A1. A mixture of 20 g of ethyl orthosilicate and 10 g of 3-aminopropyltriethoxysilane was added to an acidic emulsion (prepared by mixing hydrochloric acid, water, and surfactant Sar-Na, with a pH of 3 and a Sar-Na content of 1%), and the mixture was stirred at room temperature for 30 min. The aging liquid was poured into a reactor, which was placed at 80° C. and reacted for 12 h. The reaction was stopped, the mixture was removed, centrifuged, filtered, washed, and dried to obtain amino-modified mesoporous silica.

[0037] A2. Add amino-modified mesoporous silica to ferric nitrate solution, stir evenly, pour into a reactor, place the reactor at 80°C, react for 12 hours, stop the reaction, remove, centrifuge, filter, dry, grind, and then sinter in a muffle furnace at 600°C for 12 hours to obtain magnetic silica particles.

[0038] Example 2

[0039] Preparation of magnetic silica particles:

[0040] A1. A mixture of 30 g of ethyl orthosilicate and 10 g of 3-aminopropyltriethoxysilane was added to an acidic emulsion (prepared by mixing hydrochloric acid, water, and a surfactant Sar-Na, with a pH of 3 and a Sar-Na content of 2%), and the mixture was stirred at room temperature for 30 min. The aging liquid was poured into a reactor, which was placed at 90° C. and reacted for 8 h. The reaction was stopped, the mixture was removed, centrifuged, filtered, washed, and dried to obtain amino-modified mesoporous silica.

[0041] A2. Add amino-modified mesoporous silica to ferric nitrate solution, stir evenly, pour into a reactor, place the reactor at 90°C, react for 6 hours, stop the reaction, remove, centrifuge, filter, dry, grind, and then sinter in a muffle furnace at 650°C for 6 hours to obtain magnetic silica particles.

[0042] Example 3

[0043] Preparation of functional toughening agent:

[0044] B1. After uniformly mixing 0.1 mol of bisamino-terminated polydimethylsiloxane (relative molecular weight of 2000-5000), 0.15 mol of epoxy silane coupling agent and tetrahydrofuran, the mixture was heated to 65° C. and kept in the reaction for 10 h. The reaction was stopped, and the tetrahydrofuran was recovered by rotary evaporation, washed, and dried to obtain a macromolecular silane coupling agent;

[0045] B2. Mix 100 g of magnetic silica particles prepared in Example 1, 30 g of macromolecular silane coupling agent, 30 g of water, and 270 g of ethanol, heat to 70° C., react for 8 h, stop the reaction, age, centrifuge, filter, wash, and dry to obtain a functional toughening agent.

[0046] Example 4

[0047] Preparation of functional toughening agent:

[0048] B1. Mix 0.1 mol of bisamino-terminated polydimethylsiloxane (relative molecular weight 2000-5000), 0.2 mol of epoxy silane coupling agent (KH560) and tetrahydrofuran, heat to 70°C, keep the mixture for 3 hours, stop the reaction, recover the tetrahydrofuran by rotary evaporation, wash, and dry to obtain a macromolecular silane coupling agent;

[0049] B2. Mix 100 g of magnetic silica particles prepared in Example 2, 40 g of macromolecular silane coupling agent, 60 g of water, and 240 g of ethanol, heat to 90° C., react for 4 h, stop the reaction, age, centrifuge, filter, wash, and dry to obtain a functional toughening agent.

[0050] Comparative Example 1

[0051] Preparation of toughening agent:

[0052] B1. Mix 0.1 mol of bisamino-terminated polydimethylsiloxane (relative molecular weight 2000-5000), 0.15 mol of epoxy silane coupling agent (KH560) and tetrahydrofuran, heat to 65° C., keep the mixture for 10 h, stop the reaction, recover the tetrahydrofuran by rotary evaporation, wash, and dry to obtain a macromolecular silane coupling agent;

[0053] B2. Evenly mix 100 g of amino-modified mesoporous silica prepared in step A1 of Example 1, 30 g of a macromolecular silane coupling agent, 30 g of water, and 270 g of ethanol, heat to 70° C., react for 8 h, stop the reaction, age, centrifuge, filter, wash, and dry to obtain a toughening agent.

[0054] Comparative Example 2

[0055] Preparation of toughening agent:

[0056] 100 g of magnetic silica particles prepared in Example 1, 30 g of epoxy silane coupling agent (KH560), 30 g of water, and 270 g of ethanol were mixed evenly, heated to 70° C., reacted for 8 h, stopped the reaction, aged, centrifuged, filtered, washed, and dried to obtain a toughening agent.

[0057] Example 5

[0058] Silver-coated carbon fiber:

[0059] 50 g of carbon fiber was immersed in 150 g of dopamine solution (pH 8-9), stirred at room temperature for 3 h, filtered, washed, and dried to obtain surface-coated carbon fiber; then 50 g of surface-coated carbon fiber was immersed in 150 g of chemical silver plating solution (silver nitrate solution containing 0.1 mol silver ions, pH 8-9), excess formaldehyde solution was slowly added for reduction, stirred at room temperature for 60 min, filtered, washed, and dried to obtain silver-plated carbon fiber.

[0060] Example 6

[0061] Silver-coated carbon fiber:

[0062] 50 g of carbon fiber was immersed in 150 g of dopamine solution (pH 8-9), stirred at room temperature for 12 h, filtered, washed, and dried to obtain surface-coated carbon fiber; then 50 g of surface-coated carbon fiber was immersed in 150 g of chemical silver plating solution (silver nitrate solution containing 0.1 mol silver ions, pH 8-9), excess formaldehyde solution was slowly added for reduction, stirred at room temperature for 30 min, filtered, washed, and dried to obtain silver-plated carbon fiber.

[0063] Example 7

[0064] Preparation of PPS-based shielding film:

[0065] The first step is to prepare the following raw materials in parts by weight: 80 parts of polyphenylene sulfide, 55 parts of the functional toughening agent prepared in Example 3, and 15 parts of modified carbon fiber (silane coupling agent modified carbon fiber, KH550 surface treated carbon fiber, the specific surface treatment method is a common method in the art and will not be repeated here);

[0066] In the second step, polyphenylene sulfide and functional toughening agent are mixed and added to an inverted twin-screw extruder. The modified carbon fiber is fed from the side port. After co-extrusion, stretching and shaping, a PPS-based shielding film (film thickness 2 mm) is obtained. The co-extrusion temperature is 270-320°C, and the stretching temperature is 90-125°C.

[0067] Example 8

[0068] Preparation of PPS-based shielding film:

[0069] The first step is to prepare the following raw materials in parts by weight: 90 parts of polyphenylene sulfide, 40 parts of the functional toughening agent prepared in Example 3, and 20 parts of modified carbon fiber (silane coupling agent modified carbon fiber, KH550 surface treated carbon fiber, the specific surface treatment method is a common method in the art and will not be repeated here);

[0070] In the second step, polyphenylene sulfide and functional toughening agent are mixed and added to an inverted twin-screw extruder. The modified carbon fiber is fed from the side port. After co-extrusion, stretching and shaping, a PPS-based shielding film (film thickness 2 mm) is obtained. The co-extrusion temperature is 270-320°C, and the stretching temperature is 90-125°C.

[0071] Example 9

[0072] Preparation of PPS-based shielding film:

[0073] The first step is to prepare the following raw materials in parts by weight: 100 parts of polyphenylene sulfide, 35 parts of the functional toughening agent prepared in Example 3, and 30 parts of modified carbon fiber (silane coupling agent modified carbon fiber, KH550 surface treated carbon fiber, the specific surface treatment method is a common method in the art and will not be repeated here);

[0074] In the second step, polyphenylene sulfide and functional toughening agent are mixed and added to an inverted twin-screw extruder. The modified carbon fiber is fed from the side port. After co-extrusion, stretching and shaping, a PPS-based shielding film (film thickness 2 mm) is obtained. The co-extrusion temperature is 270-320°C, and the stretching temperature is 90-125°C.

[0075] Example 10

[0076] Preparation of PPS-based shielding film:

[0077] The first step is to prepare the following raw materials in parts by weight: 80 parts of polyphenylene sulfide, 55 parts of the functional toughening agent prepared in Example 3, and 15 parts of modified carbon fiber (silver-plated carbon fiber prepared in Example 5);

[0078] In the second step, polyphenylene sulfide and functional toughening agent are mixed and added to an inverted twin-screw extruder. The modified carbon fiber is fed from the side port. After co-extrusion, stretching and shaping, a PPS-based shielding film (film thickness 2 mm) is obtained. The co-extrusion temperature is 270-320°C, and the stretching temperature is 90-125°C.

[0079] Comparative Example 3

[0080] PPS-based shielding film: Compared with Example 7, an equal amount of the functional toughening agent is replaced by the toughening agent prepared in Comparative Example 1, and the rest is the same.

[0081] Comparative Example 4

[0082] PPS-based shielding film: Compared with Example 7, an equal amount of the functional toughening agent is replaced by the toughening agent prepared in Comparative Example 2, and the rest is the same.

[0083] Comparative Example 5

[0084] PPS-based shielding film: Compared with Example 7, the functional toughening agent is deleted, and the rest is the same.

[0085] The shielding films obtained in Examples 7-10 and Comparative Examples 3-4 were subjected to physical property tests, and the test results are shown in Table 1. The electromagnetic shielding performance test was conducted in the X-band of 8.2-12.4 GHz.

[0086] Table 1

[0087] Serial number tensile strength Notched impact strength Oxygen Index (OI) Electromagnetic shielding effectiveness Test standards GB / T 1040 GB / T 1043.1 ISO 4589-2 / unit MPa <![CDATA[KJ / m 2 ]]> ％ dB Example 7 121.2 7.3 53 3312 Example 8 114.5 7.1 52 3288 Example 9 111.7 6.9 50 3219 Example 10 122.4 7.8 53 4233 Comparative Example 3 119.3 5.6 48 1421 Comparative Example 4 111.6 5.1 46 3273 Comparative Example 5 102.9 3.8 45 1316

[0088] It can be seen from the data in Table 1 that the shielding films obtained in Examples 7-10 have good toughness and impact resistance.

[0089] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0090] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A flame retardant PPS-based shielding film, characterized in that , including the following raw materials in parts by weight: 80-100 parts of polyphenylene sulfide, 35-55 parts of functional toughening agent, and 15-30 parts of modified carbon fiber; The functional toughening agent is produced by surface treatment reaction of magnetic silicon dioxide particles and macromolecular silane coupling agent.

2. A flame retardant PPS-based shielding film according to claim 1, characterized in that , the mass ratio of the magnetic silica particles to the macromolecular silane coupling agent is 10:3-4.

3. A flame retardant PPS-based shielding film according to claim 1, characterized in that The temperature of the surface treatment reaction is 50-100°C, and the reaction time is 4-12h.

4. A flame retardant PPS-based shielding film according to claim 1, characterized in that The magnetic silica particles are prepared by mixing amino-modified mesoporous silica with a solution containing an iron source, and then undergoing a hydrothermal reaction stage and a sintering reaction stage.

5. A flame retardant PPS-based shielding film according to claim 4, characterized in that The temperature of the hydrothermal reaction stage is 75-100°C, and the reaction time is 6-12h.

6. The flame retardant PPS-based shielding film according to claim 1, characterized in that The macromolecular silane coupling agent is prepared by reacting bisamino-terminated polydimethylsiloxane and epoxy silane coupling agent.

7. A flame retardant PPS-based shielding film according to claim 6, characterized in that , the molar ratio of the bisamino-terminated polydimethylsiloxane to the epoxy silane coupling agent is 1:1-2.

8. The flame retardant PPS-based shielding film according to claim 6, characterized in that , the relative molecular mass of the bis-amino-terminated polydimethylsiloxane is 2000-5000.

9. The flame retardant PPS-based shielding film according to claim 1, characterized in that The modified carbon fiber is one of silane coupling agent modified carbon fiber and silver-plated carbon fiber.

10. The method for preparing a flame-retardant PPS-based shielding film according to any one of claims 1 to 9, characterized in that ,include: The polyphenylene sulfide, functional toughening agent and modified carbon fiber are blended, extruded, stretched and shaped to obtain a PPS-based shielding film.