Electromagnetic shielding foam material and preparation and forming method thereof

Abstract

The invention discloses an electromagnetic shielding foam material and a preparation forming method thereof, and relates to the technical field of polymer processing. The electromagnetic shielding foam material is prepared by adopting polyphenylene sulfide as a raw material, so that the mechanical strength of the electromagnetic shielding foam material is high, and PPS has excellent mechanical strength, tensile strength, bending strength and other indexes which are at a relatively high level in engineering plastics, and can bear relatively high pressure and wear; the melting point of the PPS exceeds 280 DEG C, the heat distortion temperature exceeds 260 DEG C, the PPS can resist the high temperature of 260 DEG C in a short term, the long-term use temperature can reach 200-220 DEG C, and the PPS still can keep good performance at the high temperature; the PPS has excellent electrical insulation property, low dielectric constant and dielectric loss angle tangent value and good arc resistance, and is suitable for insulating materials in the field of electronic and electric appliances; excellent chemical corrosion resistance and radiation resistance are realized; the PPS electromagnetic shielding foam material prepared by a special process also has a good electromagnetic shielding effect, and can be used in occasions requiring electromagnetic shielding.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer processing, and in particular relates to an electromagnetic shielding foam material and a preparation and molding method thereof. Background Art

[0002] Polyphenylene sulfide (PPS), as a high-temperature resistant thermoplastic crystalline special engineering plastic, is one of the resins with the highest thermal stability among thermoplastics. It has excellent mechanical properties and excellent flame retardancy, corrosion resistance, electrical insulation, etc. Its electromagnetic shielding foam material has the characteristics of light weight, high strength and heat resistance, and has broad application prospects in aerospace, national defense, military industry, electronic communications and other fields.

[0003] Traditional electromagnetic shielding materials, such as metal shielding, have good shielding effectiveness, but they are heavy and are not suitable for occasions with strict weight requirements. In addition, the price of traditional electromagnetic shielding materials such as metals is relatively high, which increases the manufacturing cost and is not conducive to large-scale application. Metal shielding materials that are susceptible to corrosion and oxidation are easily damaged in humid or corrosive environments, affecting their shielding effect and service life. Traditional materials such as metals may have many difficulties in the processing process, such as cutting, bending and other complex processes, and are prone to processing defects. The electromagnetic shielding effectiveness is limited. Although some non-metallic materials are light, their electromagnetic shielding effectiveness is relatively low, and they may not meet the application scenarios with high shielding requirements. Therefore, an electromagnetic shielding foam material and a preparation and molding method thereof are proposed. Summary of the invention

[0004] The purpose of the present invention is to provide an electromagnetic shielding foam material and a preparation and molding method thereof to solve the existing problems.

[0005] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] The present invention is a method for preparing and molding an electromagnetic shielding foam material, comprising the following steps:

[0007] S1, add 100 parts of bisphenol A epoxy resin, 20-50 parts of polyoxypropylene diamine with a molecular weight of 500-2000 g / mol, 20-50 parts of diethylaminopropylamine, 5-15 parts of o-cresol and polypropylene glycol diglycidyl ether into a beaker in sequence, and stir evenly;

[0008] S2, adding 1-5 parts of graphene and mixing evenly to obtain an epoxy resin / graphene barrier layer composite curing system;

[0009] S3, placing PPS particles with a particle size of 3 mm in an autoclave for sc-CO2 pre-saturation at 8-18 MPa and 45-85°C, and taking them out of the autoclave after 5-18 hours;

[0010] S4, immersing the PPS particles taken out in S3 in the epoxy resin / graphene barrier layer composite curing system obtained in S2, and then curing it at 40-85° C. for 30-140 min to obtain PPS particles with epoxy resin / graphene barrier layer coated on the surface;

[0011] S5, then placing the PPS particles obtained in S4 in an autoclave for a secondary sc-CO2 saturation process, and cooling to 30-50°C, performing rapid pressure relief, and immediately taking out the sample and placing it in a 100-220°C oil bath for heating and foaming;

[0012] S6, after the pores are cooled and shaped, the epoxy resin / graphene barrier layer is peeled off from the surface of the foamed PPS beads to obtain skinless PPS foamed beads;

[0013] S7, add 100 parts of aminophenol trifunctional epoxy resin, 5-18 parts of active terminal hydroxyl polydimethylsiloxane with a molecular weight of 1000-30000 g / mol, 60-120 parts of maleic anhydride, and 5-50 parts of acetone to a beaker in sequence, stir evenly, then add carbon nanotubes, stir evenly, and obtain an epoxy resin / carbon nanotube composite adhesive;

[0014] S8. Mix the prepared skinless PPS foam beads with epoxy resin / carbon nanotube composite adhesive in a mass ratio of 2:1, 1:1, and 1:2, respectively, so that the composite adhesive is fully coated on the surface of the skinless PPS foam beads, and then stack and arrange them in a polytetrafluoroethylene mold, and perform high-temperature curing at 100-180°C to obtain a PPS-based electromagnetic shielding foam material.

[0015] Furthermore, in step S1, the polyoxypropylene diamine is a polyetheramine curing agent, the diethylaminopropylamine is a fatty amine curing agent, the o-cresol is a phenolic accelerator, and the polypropylene glycol diglycidyl ether is a reactive diluent.

[0016] Furthermore, in step S7, the maleic anhydride is an anhydride curing agent, and the acetone is a diluent.

[0017] An electromagnetic shielding foam material is prepared by the above-mentioned preparation and molding method.

[0018] The present invention has the following beneficial effects:

[0019] The invention adopts polyphenylene sulfide as a raw material to prepare an electromagnetic shielding foam material, so that the mechanical strength of the PPS is high. The PPS has excellent mechanical strength, and the tensile strength, bending strength and other indicators are at a relatively high level in engineering plastics, and can withstand greater pressure and wear; the thermal stability is good, the melting point of the PPS exceeds 280°C, the heat deformation temperature exceeds 260°C, the PPS can withstand a high temperature of 260°C in a short term, and the long-term use temperature can reach 200-220°C, and the PPS can still maintain good performance at high temperatures; the electrical properties are excellent, the PPS has excellent electrical insulation properties, a low dielectric constant and a dielectric loss tangent value, and good arc resistance, and is suitable for insulating materials in the field of electronic appliances; it has excellent chemical corrosion resistance and radiation resistance; the PPS electromagnetic shielding foam material prepared by a special process also has a good electromagnetic shielding effect, and can be used in occasions requiring electromagnetic shielding.

[0020] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0022] Figure 1 The present invention is a flow chart of a method for preparing and molding an electromagnetic shielding foam material. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0024] In the description of the present invention, it should be understood that the terms "upper", "middle", "outer", "inner" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] See also Figure 1 As shown, the present invention is a method for preparing and molding an electromagnetic shielding foam material, comprising the following steps:

[0027] S1, add 100 parts of bisphenol A epoxy resin, 30 parts of polyoxypropylene diamine with a molecular weight of 1500g / mol, 20 parts of diethylaminopropylamine, 2 parts of o-cresol and 30 parts of polypropylene glycol diglycidyl ether into a beaker in sequence and stir evenly;

[0028] S2, adding 2 parts of graphene and mixing evenly to obtain an epoxy resin / graphene barrier layer composite curing system;

[0029] S3, placing PPS particles with a particle size of 3 mm in an autoclave for sc-CO2 pre-saturation at 8-18 MPa and 45-85°C, and taking them out of the autoclave after 5-18 hours;

[0030] S4, immersing the PPS particles taken out in S3 in the epoxy resin / graphene barrier layer composite curing system obtained in S2, and then curing it at 40-85° C. for 30-140 min to obtain PPS particles with epoxy resin / graphene barrier layer coated on the surface;

[0031] S5, then placing the PPS particles obtained in S4 in an autoclave for a secondary sc-CO2 saturation process, and cooling to 30-50°C, performing rapid pressure relief, and immediately taking out the sample and placing it in a 100-220°C oil bath for heating and foaming;

[0032] S6, after the pores are cooled and shaped, the epoxy resin / graphene barrier layer is peeled off from the surface of the foamed PPS beads to obtain skinless PPS foamed beads;

[0033] S7, 100 parts of aminophenol trifunctional epoxy resin, 8 parts of active hydroxy-terminated polydimethylsiloxane with a molecular weight of 3000 g / mol, 80 parts of maleic anhydride, and 30 parts of acetone are sequentially added into a beaker, stirred evenly, and then 18 parts of carbon nanotubes are added, stirred evenly, to obtain an epoxy resin / carbon nanotube composite adhesive;

[0034] S8. Mix the prepared skinless PPS foam beads and epoxy resin / carbon nanotube composite adhesive in a mass ratio of 1:1, so that the composite adhesive is fully coated on the surface of the skinless PPS foam beads, and then stack and arrange them in a polytetrafluoroethylene mold, and perform high-temperature curing at 120°C to obtain a PPS-based electromagnetic shielding foam material.

[0035] In one embodiment, in step S1, polyoxypropylene diamine is a polyetheramine curing agent, diethylaminopropylamine is a fatty amine curing agent, o-cresol is a phenolic accelerator, and polypropylene glycol diglycidyl ether is a reactive diluent.

[0036] In one embodiment, in step S7, maleic anhydride is used as an anhydride curing agent and acetone is used as a diluent.

[0037] An electromagnetic shielding foam material is prepared by the above-mentioned preparation and molding method.

[0038] It should be further explained that polyphenylene sulfide (PPS) electromagnetic shielding foam material has many advantages, as follows:

[0039] 1. High mechanical strength

[0040] PPS has excellent mechanical strength. Its tensile strength, flexural strength and other indicators are at a relatively high level among engineering plastics and can withstand greater pressure and wear.

[0041] 2. Good thermal stability

[0042] The melting point of PPS exceeds 280℃, and the heat deformation temperature exceeds 260℃. It can withstand high temperatures of 260℃ in the short term and can be used at temperatures of 200-220℃ in the long term, and can still maintain good performance at high temperatures.

[0043] 3. Excellent electrical performance

[0044] PPS has excellent electrical insulation properties, low dielectric constant and dielectric loss tangent, and good arc resistance, making it suitable as an insulating material in the field of electronics and electrical appliances.

[0045] 4. Chemical corrosion resistance

[0046] PPS is stable to most acids, esters, copper, phenols, aliphatic hydrocarbons, aromatic hydrocarbons, chlorinated hydrocarbons, etc., and has excellent chemical corrosion resistance and radiation resistance.

[0047] 5. Electromagnetic shielding performance

[0048] The PPS electromagnetic shielding foam material prepared by a special process also has a good electromagnetic shielding effect and can be used in situations where electromagnetic shielding is required.

[0049] In summary, these advantages make polyphenylene sulfide electromagnetic shielding foam materials have broad application prospects in the fields of electronics, electrical, automobiles, aerospace, etc.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0051] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing and molding an electromagnetic shielding foam material, characterized in that: The following steps are involved: S1, add 100 parts of bisphenol A epoxy resin, 20-50 parts of polyoxypropylene diamine with a molecular weight of 500-2000 g / mol, 20-50 parts of diethylaminopropylamine, 5-15 parts of o-cresol and polypropylene glycol diglycidyl ether into a beaker in sequence, and stir evenly; S2, adding 1-5 parts of graphene and mixing evenly to obtain an epoxy resin / graphene barrier layer composite curing system; S3, placing PPS particles with a particle size of 3 mm in an autoclave for sc-CO2 pre-saturation at 8-18 MPa and 45-85°C, and taking them out of the autoclave after 5-18 hours; S4, immersing the PPS particles taken out in S3 in the epoxy resin / graphene barrier layer composite curing system obtained in S2, and then curing it at 40-85° C. for 30-140 min to obtain PPS particles with epoxy resin / graphene barrier layer coated on the surface; S5, then placing the PPS particles obtained in S4 in an autoclave for a secondary sc-CO2 saturation process, and cooling to 30-50°C, performing rapid pressure relief, and immediately taking out the sample and placing it in a 100-220°C oil bath for heating and foaming; S6, after the pores are cooled and shaped, the epoxy resin / graphene barrier layer is peeled off from the surface of the foamed PPS beads to obtain skinless PPS foamed beads; S7, add 100 parts of aminophenol trifunctional epoxy resin, 5-18 parts of active terminal hydroxyl polydimethylsiloxane with a molecular weight of 1000-30000 g / mol, 60-120 parts of maleic anhydride, and 5-50 parts of acetone to a beaker in sequence, stir evenly, then add carbon nanotubes, stir evenly, and obtain an epoxy resin / carbon nanotube composite adhesive; S8. Mix the prepared skinless PPS foam beads with epoxy resin / carbon nanotube composite adhesive in a mass ratio of 2:1, 1:1, and 1:2, respectively, so that the composite adhesive is fully coated on the surface of the skinless PPS foam beads, and then stack and arrange them in a polytetrafluoroethylene mold, and perform high-temperature curing at 100-180°C to obtain a PPS-based electromagnetic shielding foam material.

2. The method for preparing and molding an electromagnetic shielding foam material according to claim 1, characterized in that: In step S1, the polyoxypropylene diamine is a polyetheramine curing agent, the diethylaminopropylamine is a fatty amine curing agent, the o-cresol is a phenolic accelerator, and the polypropylene glycol diglycidyl ether is a reactive diluent.

3. The method for preparing and molding an electromagnetic shielding foam material according to claim 1, characterized in that: In step S7, the maleic anhydride is an anhydride curing agent, and the acetone is a diluent.

4. An electromagnetic shielding foam material, characterized in that: The method is prepared by applying the preparation and molding method described in any one of claims 1 to 3.

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