A method of making a self-protected electrically conductive, foamed, gradient filtration media

Abstract

This invention provides a method for preparing a self-protective conductive foamed gradient filter material. The method involves directly generating conductive protective layers on the upper and lower surfaces of the intermediate glass fiber layer, thus making the filter material itself conductive. It includes a top foamed layer, an intermediate glass fiber layer, and a bottom foamed layer. After the intermediate glass fiber layer is fabricated, conductive protective layers are directly generated on the top and bottom surfaces of the intermediate glass fiber layer through foaming. Both the top and bottom foamed layers are thermoplastic polymer protective layers containing conductive substances, prepared through a foaming process.

Description

Technical Field

[0001] This invention relates to the technical field of filter media, specifically to a method for preparing a self-protected conductive foamed gradient filter media. Background Technology

[0002] Existing filter media used for filtering hydraulic oil, lubricating oil, and fuel oil are mostly composed of polyester fiber and glass fiber. Therefore, when oil passes through these media, a voltage is generated. If this voltage accumulates to a certain level, it can break down the filter media, significantly reducing its filtration efficiency. To solve this problem, conductive metal wires are typically added to create conductive filter media to improve conductivity. However, these conductive metal wires lack bonding strength with other parts of the filter media, leading to easy detachment. Therefore, making the filter media itself conductive has become a pressing technical challenge for oil filtration. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for preparing a self-protected conductive foamed gradient filter material, which directly generates a conductive protective layer on the upper and lower surfaces of the intermediate glass fiber layer, thereby making the filter material itself conductive.

[0004] A method for preparing a self-protective conductive foamed gradient filter material, characterized in that it includes a top foamed layer, a middle glass fiber layer, and a bottom foamed layer. After the middle glass fiber layer is prepared, a protective layer with conductive properties is directly generated on the top and bottom layers of the middle glass fiber layer through foaming. The top foamed layer and the bottom foamed layer are both thermoplastic polymer protective layers containing conductive substances obtained by foaming process.

[0005] Its further features are: The thermoplastic polymer is foamed polyester or foamed polyurethane; The conductive material is specifically an inorganic material such as carbon black, carbon nanotubes, graphene, metal powder, metal fiber, or metal foil. The conductive material is specifically an organic material such as conductive polyester, conductive polyaniline, or conductive polypyrrole. The air permeability of the top foam layer gradually decreases from top to bottom; the air permeability of the middle glass fiber layer also gradually decreases from top to bottom, thus playing a gradient filtration role.

[0006] Its further characteristic lies in the following specific operating steps: S1 first uses a wet process to prepare a glass fiber layer to obtain an intermediate glass fiber layer; S2 drying of the intermediate glass fiber layer; S3 is foamed on the inlet and outlet surfaces of the intermediate glass fiber layer, respectively. The foaming agents are nitrogen and carbon dioxide, and the foaming material is a thermoplastic polymer plus a conductive substance. S4 generates a top foam layer and a bottom foam layer on the top and bottom layers of the intermediate glass fiber layer.

[0007] Its further characteristic is: In step S1, the weight of the intermediate glass fiber layer is 25 to 180 g / m², and the air permeability ranges from 1 to 180 cubic feet / min. In step S3, the foaming pressure changes from a minimum pressure equal to atmospheric pressure to a maximum of 350 bar. In step S3, the weight of the top foam layer is 20-100 g / m², and the air permeability of the foam is 200-1400 cubic feet / minute. In step S3, the weight of the foamed product in the bottom foam layer is 20-50 g / m², and the air permeability is 500-1400 cubic feet / min. The final product obtained in step S4 has a weight of 65–330 g / m² and an air permeability of 1–180 cubic feet / min.

[0008] A self-protected conductive foamed gradient filter material is characterized in that it comprises a top foamed layer, a middle glass fiber layer, and a bottom foamed layer; the top foamed layer and the bottom foamed layer are both foamed polyester or polyurethane with conductive materials, and the top foamed layer and the bottom foamed layer protect the middle glass fiber layer.

[0009] Its further features are: The conductive material is an inorganic or organic material; when the conductive material is an inorganic material, it is specifically carbon black, carbon nanotubes, graphene, metal powder, metal fiber, or metal foil; when the conductive material is an organic material, it is specifically conductive polyester, conductive polyaniline, or conductive polypyrrole. The air permeability of the top foam layer is 200-1400 cubic feet / minute and the weight is 20-100 grams / square meter, and the air permeability of the top foam layer gradually decreases from top to bottom. The air permeability of the intermediate glass fiber layer is 1 to 180 cubic feet per minute and the weight is 25 to 180 grams per square meter, and the air permeability of the intermediate glass fiber layer gradually decreases from top to bottom. The weight of the foamed product in the bottom foam layer is 20-50 g / m², and the air permeability is 500-1400 cubic feet / min. In this gradient product, the top foam layer has abundant pores, which can serve as a protective layer and, with proper air permeability design, form a gradient structure with the bottom foam layer, thus improving the dirt holding capacity.

[0010] With the solution of this invention, the top and bottom layers are foamed products with a porous structure directly generated on the middle glass fiber layer using a foaming process. The middle layer is a glass fiber filter layer made by wet papermaking. The filter material is obtained directly on the upper and lower surfaces of the middle glass fiber layer through foaming, which is simple to manufacture and reduces the manufacturing cost. Moreover, both the top foam layer and the bottom foam layer are thermoplastic polymer protective layers containing conductive substances prepared by a foaming process. On the one hand, they protect the middle glass fiber layer, and on the other hand, the presence of conductive materials will greatly improve the conductivity of the filter material, thereby making the composite filter material itself conductive. Attached Figure Description

[0011] Figure 1 This is a magnified schematic diagram of the filter material corresponding to this invention under an electron microscope. Detailed Implementation

[0012] A method for preparing a self-protected conductive foamed gradient filter material includes a top foamed layer, a middle glass fiber layer, and a bottom foamed layer. After the middle glass fiber layer is prepared, a conductive protective layer is directly generated on the top and bottom layers of the middle glass fiber layer through foaming. Both the top foamed layer and the bottom foamed layer are thermoplastic polymer protective layers containing conductive substances obtained through a foaming process.

[0013] In practice, the thermoplastic polymer is either foamed polyester or foamed polyurethane; Conductive materials specifically include inorganic materials such as carbon black, carbon nanotubes, graphene, metal powder, metal fibers, and metal foils; Alternatively, the conductive material may be a specific organic material such as conductive polyester, conductive polyaniline, or conductive polypyrrole.

[0014] The air permeability of the top foam layer gradually decreases from top to bottom; the air permeability of the middle glass fiber layer also gradually decreases from top to bottom, thus playing a gradient filtration role.

[0015] The specific operating steps are as follows: S1 first uses a wet process to prepare a glass fiber layer, thereby obtaining an intermediate glass fiber layer. The basis weight of the intermediate glass fiber layer is 25–180 g / m², and the air permeability ranges from 1–180 cubic feet / min. S2 drying of the intermediate glass fiber layer; S3 involves foaming the inlet (carpet surface) and outlet (mesh surface) of the intermediate glass fiber layer separately. The foaming agents are nitrogen and carbon dioxide, and the foaming materials are thermoplastic polymers and conductive substances. The foaming pressure varies from a minimum of atmospheric pressure to a maximum of 350 bar. The weight of the top foam layer is 20–100 g / m², and the air permeability is 200–1400 cubic feet / min. The weight of the bottom foam layer is 20–50 g / m², and the air permeability is 500–1400 cubic feet / min. S4 generates a top foam layer and a bottom foam layer on the top and bottom layers of the intermediate glass fiber layer; the final product has a basis weight of 65 to 330 g / m² and an air permeability of 1 to 180 cubic feet / min.

[0016] A self-protected conductive foamed gradient filter media, see Figure 1 It includes a top foam layer, a middle fiberglass layer, and a bottom foam layer; the top foam layer and the bottom foam layer are both foamed polyester or polyurethane with conductive materials, and the top foam layer and the bottom foam layer protect the middle fiberglass layer.

[0017] In practice, the conductive material can be either inorganic or organic. When the conductive material is inorganic, it can be carbon black, carbon nanotubes, graphene, metal powder, metal fiber, or metal foil. When the conductive material is organic, it can be conductive polyester, conductive polyaniline, or conductive polypyrrole. The air permeability of the top foam layer is 200-1400 cubic feet / minute and the weight is 20-100 grams / square meter, and the air permeability of the top foam layer gradually decreases from top to bottom; The air permeability of the middle glass fiber layer is 1–180 cubic feet per minute and the weight is 25–180 grams per square meter, and the air permeability of the middle glass fiber layer gradually decreases from top to bottom; The weight of the foamed product in the bottom layer is 20-50 g / m², and the air permeability is 500-1400 cubic feet / minute. In this gradient product, the top foam layer has abundant pores, which can serve as a protective layer and, with proper air permeability design, form a gradient structure with the bottom foam layer, thus improving the dirt holding capacity.

[0018] The top and bottom layers are foamed products with a porous structure, directly formed on the middle glass fiber layer using a foaming process. The middle layer is a glass fiber filter layer produced by wet-process papermaking. The filter material is obtained by foaming directly on the upper and lower surfaces of the middle glass fiber layer, which is simple to manufacture and reduces production costs. Both the top and bottom foamed layers are thermoplastic polymer protective layers containing conductive substances, prepared through a foaming process. On the one hand, they protect the middle glass fiber layer, and on the other hand, the presence of conductive materials significantly increases the conductivity of the filter material, thus making the composite filter material itself conductive.

[0019] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0020] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing a self-protected conductive foamed gradient filter material, characterized in that, It includes a top foam layer, a middle glass fiber layer, and a bottom foam layer. After the middle glass fiber layer is manufactured, a protective layer with conductive properties is directly generated on the top and bottom layers of the middle glass fiber layer through foaming. Both the top foam layer and the bottom foam layer are thermoplastic polymer protective layers containing conductive substances, which are prepared by foaming process.

2. The method for preparing a self-protected conductive foamed gradient filter material according to claim 1, characterized in that: The air permeability of the top foam layer gradually decreases from top to bottom; the air permeability of the middle glass fiber layer also gradually decreases from top to bottom, thus playing a gradient filtration role.

3. The preparation method of the self-protected conductive foamed gradient filter material according to claim 1, the specific operation steps are as follows: S1 first uses a wet process to prepare a glass fiber layer to obtain an intermediate glass fiber layer; S2 drying of the intermediate glass fiber layer; S3 is foamed on the inlet and outlet surfaces of the intermediate glass fiber layer, respectively. The foaming agents are nitrogen and carbon dioxide, and the foaming material is a thermoplastic polymer plus a conductive substance. S4 generates a top foam layer and a bottom foam layer on the top and bottom layers of the intermediate glass fiber layer.

4. The method for preparing a self-protected conductive foamed gradient filter material according to claim 3, characterized in that: In step S1, the weight of the intermediate glass fiber layer is 25 to 180 grams per square meter, and the air permeability ranges from 1 to 180 cubic feet per minute.

5. The method for preparing a self-protected conductive foamed gradient filter material according to claim 3, characterized in that: In step S3, the foaming pressure changes from a minimum pressure equal to atmospheric pressure to a maximum of 350 bar.

6. The method for preparing a self-protected conductive foamed gradient filter material according to claim 5, characterized in that: In step S3, the weight of the top foam layer is 20-100 g / m², and the air permeability is 200-1400 cubic feet / minute; the weight of the bottom foam layer is 20-50 g / m², and the air permeability is 500-1400 cubic feet / minute.

7. The method for preparing a self-protected conductive foamed gradient filter material according to claim 5, characterized in that: The final product obtained in step S4 has a weight of 65–330 g / m² and an air permeability of 1–180 cubic feet / min.

8. A self-protected conductive foamed gradient filter material, prepared by the preparation method of any one of claims 1 to 7, characterized in that: It includes a top foam layer, a middle glass fiber layer, and a bottom foam layer; the top foam layer and the bottom foam layer are both foamed polyester or polyurethane with conductive materials, and the top foam layer and the bottom foam layer protect the middle glass fiber layer.

9. The self-protected conductive foamed gradient filter material according to claim 8, characterized in that: The conductive material is an inorganic or organic material; when the conductive material is an inorganic material, it is specifically carbon black, carbon nanotubes, graphene, metal powder, metal fiber, or metal foil; when the conductive material is an organic material, it is specifically conductive polyester, conductive polyaniline, or conductive polypyrrole.

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