阅读说明：本技术 一种吸波夹心泡沫及其制备方法 (wave-absorbing sandwich foam and preparation method thereof ) 是由 姚栋嘉 吕多军 吴恒 张东生 刘喜宗 杨超 董会娜 杨红霞 于 2019-09-12 设计创作，主要内容包括：本发明属于吸波材料技术领域,公开一种吸波夹心泡沫及其制备方法。(1)、平铺放置一层玻璃纤维布；(2)、在玻璃纤维布表面采用液体静电喷涂设备喷涂液体热固性树脂和固化剂的混合物,得到热固性树脂层；(3)、采用静电植绒的方法在步骤(2)的基础上垂直定向植入碳纳米管；(4)、利用粉体静电喷涂设备在步骤(3)的基础上喷涂一层空心玻璃微球；(5)、利用液体静电喷涂设备在步骤(4)的基础上继续喷涂液体热固性树脂和固化剂的混合物,再次得到热固性树脂层；(6)、在步骤(5)的基础上重新叠加一层玻璃纤维布,即得吸波夹心泡沫。本发明吸波夹心泡沫,具有低密度、高的拉伸模量和压缩强度等特性。(The invention belongs to the technical field of wave absorbing materials, and discloses wave absorbing sandwich foams and a preparation method thereof, (1) layers of glass fiber cloth are flatly laid, (2) a mixture of liquid thermosetting resin and a curing agent is sprayed on the surface of the glass fiber cloth by adopting liquid electrostatic spraying equipment to obtain a thermosetting resin layer, (3) carbon nano tubes are vertically implanted on the basis of the step (2) by adopting an electrostatic flocking method, (4) layers of hollow glass microspheres are sprayed on the basis of the step (3) by utilizing powder electrostatic spraying equipment, (5) the mixture of the liquid thermosetting resin and the curing agent is continuously sprayed on the basis of the step (4) by utilizing the liquid electrostatic spraying equipment to obtain the thermosetting resin layer again, and (6) layers of glass fiber cloth are superposed again on the basis of the step (5) to obtain the wave absorbing sandwich foam.)

The preparation method of the wave-absorbing sandwich foam of 1 and kinds is characterized by comprising the following steps:

(1) layers of glass fiber cloth are laid flatly;

(2) spraying a mixture of liquid thermosetting resin and a curing agent on the surface of the glass fiber cloth by adopting liquid electrostatic spraying equipment to obtain a thermosetting resin layer;

(3) implanting carbon nanotubes in a vertical orientation manner on the basis of the step (2) by adopting an electrostatic flocking method;

(4) spraying layers of hollow glass microspheres on the basis of the step (3) by using powder electrostatic spraying equipment;

(5) continuously spraying a mixture of liquid thermosetting resin and a curing agent by using liquid electrostatic spraying equipment on the basis of the step (4) to obtain a thermosetting resin layer again;

(6) and (5) superposing layers of glass fiber cloth again on the basis of the step (5) to obtain the wave-absorbing sandwich foam.

2. The method for preparing the wave-absorbing sandwich foam according to claim 1, which is characterized by comprising the following steps: in the steps (1) and (6), the surface density of the glass fiber cloth is 80-120 g/m²。

3. The preparation method of the wave-absorbing sandwich foam according to claim 1, wherein in the steps (2) and (5), the mass ratio of the liquid thermosetting resin to the curing agent is 100: 20-180, the liquid thermosetting resin is of epoxy resin, polyurethane resin and phenolic resin, the curing agent is 593 of the curing agent, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dicyandiamide, imidazoles, methyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, triethylene diamine and of triethylene tetramine or a mixture of more than two of the curing agent, the curing agent is added when the liquid thermosetting resin is epoxy resin or polyurethane resin, and the curing agent is added or not added when the liquid thermosetting resin is phenolic resin.

4. The method for preparing the wave-absorbing sandwich foam according to claim 1, which is characterized by comprising the following steps: in the steps (2) and (5), the thickness of the thermosetting resin layer obtained by each spraying is controlled to be 50-60 mu m.

5. The method for preparing the wave-absorbing sandwich foam according to claim 1, which is characterized by comprising the following steps: in the step (3), the length of the carbon nano tube is 15-30 μm, and the average diameter is 30-50 nm.

6. The method for preparing the wave-absorbing sandwich foam according to claim 1, which is characterized by comprising the following steps: in the step (3), the voltage of electrostatic flocking is 50-80 kV, and the flocking time is 5-10 s.

7. The method for preparing the wave-absorbing sandwich foam according to claim 1, which is characterized by comprising the following steps: in the step (4), the density range of the hollow glass microspheres is 0.1-1 g/cm³The thickness of the sprayed hollow glass microspheres is controlled to be 1-1.5 mm.

8, microwave absorbing sandwich foams prepared by the method for preparing the microwave absorbing sandwich foam according to any of claims 1-7.

Technical Field

The invention belongs to the technical field of wave-absorbing materials, and particularly relates to wave-absorbing sandwich foams and a preparation method thereof.

Background

Syntactic foams originated in the 60's of the last century, when mainly used as buoyancy materials for underwater devices in the marine field, such as underwater robots, diving bells, etc. Meanwhile, other types of foam materials cannot meet the requirements, and under the condition of higher hydrostatic pressure, the common foam material usually has the phenomenon that cell units are communicated after being broken, so that the capacity of providing buoyancy is greatly reduced. Unlike conventional foam-type materials, syntactic foams can have high compressive strength because the cell structure is composed of rigid hollow spheres, which are independent of each other, thereby minimizing the water absorption of the material. With the progress of technology and the development of times, the types and application fields of the composite foam are gradually expanded, the raw materials are not limited to hollow glass microspheres and resin matrixes any more, and the application range is expanded from the underwater field to the fields of aerospace, automobiles, electronic equipment, home decoration and the like.

The composite foam has good wave absorption characteristics based on unique performance, and the novel wave absorbing material is required to have light weight, high strength, wide frequency band, strong absorption, environmental friendliness and the like.

Disclosure of Invention

Aiming at the problems of high processing difficulty, high production cost and the like when the composite foam is used as the sandwich foam of the thin-layer composite sandwich board, the invention aims to provide wave-absorbing sandwich foams and a preparation method thereof.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the preparation method of wave-absorbing sandwich foams comprises the following steps:

(1) layers of glass fiber cloth are laid flatly;

(2) spraying a mixture of liquid thermosetting resin and a curing agent on the surface of the glass fiber cloth by adopting liquid electrostatic spraying equipment to obtain a thermosetting resin layer;

(3) implanting carbon nanotubes in a vertical orientation manner on the basis of the step (2) by adopting an electrostatic flocking method;

(4) spraying layers of hollow glass microspheres on the basis of the step (3) by using powder electrostatic spraying equipment;

(5) continuously spraying a mixture of liquid thermosetting resin and a curing agent by using liquid electrostatic spraying equipment on the basis of the step (4) to obtain a thermosetting resin layer again;

(6) and (5) superposing layers of glass fiber cloth again on the basis of the step (5) to obtain the wave-absorbing sandwich foam.

Preferably, in the steps (1) and (6), the surface density of the glass fiber cloth is 80-120 g/m²。

Preferably, in the steps (2) and (5), the mass ratio of the liquid thermosetting resin to the curing agent is 100: 20-180, the liquid thermosetting resin is of epoxy resin, polyurethane resin and phenolic resin, the curing agent is or a mixture of more than two of 593 curing agents, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dicyandiamide, imidazoles, methyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, triethylene diamine and triethylene tetramine, the curing agent is added when the liquid thermosetting resin is epoxy resin or polyurethane resin, and the curing agent is added or not added when the liquid thermosetting resin is phenolic resin.

Preferably, in the steps (2) and (5), the thickness of the thermosetting resin layer obtained by each spraying is controlled to be 50-60 μm.

Preferably, in step (3), the carbon nanotubes have a length of 15 to 30 μm and an average diameter of 30 to 50 nm.

Preferably, in the step (3), the voltage of electrostatic flocking is 50-80 kV, and the flocking time is 5-10 s.

Preferably, in step (4), the density of the hollow glass microspheres is in the range of 0.1-1 g/cm³The thickness of the sprayed hollow glass microspheres is controlled to be 1-1.5 mm.

wave-absorbing sandwich foams prepared by the preparation method.

Has the advantages that:

1. according to the invention, the carbon nano tubes are vertically implanted on the surface of the glass fiber cloth by adopting a directional flocking method, so that the carbon nano tube layer is more uniform and -shaped, the improvement of the wave absorption performance of the glass fiber cloth is facilitated, the hollow glass microspheres are uniformly layered by adopting electrostatic spraying and are integrally formed by thermosetting resin , the structure is simple, the operation is convenient, the layers are directly and tightly arranged, and the electromagnetic wave can be effectively attenuated;

2. the carbon nano tubes directly oriented can improve the tensile modulus of the glass fiber cloth, and in addition, the hollow glass microspheres are fixed to degrees, the hollow glass microspheres, the carbon nano tubes and the glass fiber cloth can be well bonded into whole bodies under the action of thermosetting resin, and semi-solidified composite foam layers, namely the wave-absorbing sandwich foam of the invention, are obtained, and the composite foam layers have the characteristics of low density, high tensile modulus, compressive strength and the like;

3. based on the wave-absorbing characteristics of the carbon nano tube and the composite foam, the composite foam can be directly cured and molded with bodies with other wave-absorbing materials at the later stage to obtain the wave-absorbing composite foam with excellent performance, the secondary processing operation is simple and convenient, the method for preparing the sandwich foam has simple process, short operation period and high production efficiency, and the prepared sandwich foam has broad application prospect on the wave-absorbing composite foam used in the fields of ocean radar and the like.

Detailed Description

The technical solution of the present invention is further described in with reference to specific embodiments, but the scope of the present invention is not limited thereto.