Processing method of polypropylene conductive coating stiff filter material

Abstract

The invention relates to the related field of filter materials, in particular to a processing method of a polypropylene fiber conductive coating stiff filter material, which realizes processing of a polypropylene fiber conductive filter material and processing of a stiff foldable polypropylene fiber filter material through combined processing of needling and dipping processes. During processing, the polypropylene fiber has corrosion resistance and is suitable for filtering high smoke dust in a severe working condition environment; the composite filter material disclosed by the invention has good conductive and explosion-proof functions, and the surface resistance is about 104 power.

Description

Technical Field

[0001] The present invention relates to the field of filter materials, and specifically to a processing method for a polypropylene conductive coating stiff filter material. Background Art

[0002] In recent years, with the development and progress of environmental protection science and technology, the air filtration market has started to develop towards high-efficiency energy-saving production and green environmental protection, requiring filter materials to have acid and alkali resistance and corrosion resistance. At the same time, high-efficiency filters require a small volume, high wind speed, and large air volume. The folded cartridge filter bag adapts to the development direction of filter materials and realizes the process of folding the cartridge through its own hardening treatment. Currently, traditional filter bags are gradually being replaced by folded filter cartridges. The folded cartridge filter bag effectively increases the filtration area of the material through the folding treatment, increasing the filtration area by more than 50% compared to traditional filter bags. Polypropylene fibers have good chemical corrosion resistance, and endowing the fabric with conductive ability through conductive coating treatment expands the application range of polypropylene folded filter materials, especially in places with high dust and easy electrostatic accumulation. Using conductive polypropylene folded cartridges can effectively reduce costs.

[0003] Polypropylene fiber filter materials have excellent acid resistance, alkali resistance, chemical corrosion resistance, as well as excellent wear resistance and tensile resistance. Therefore, it can filter under various harsh environmental conditions and maintain its filtration performance. Polypropylene filter materials can be made into filter materials of different shapes and specifications according to specific application requirements, such as horizontal belt type, vertical type, and filter cloth for leaf filters, and are applied in fields such as chemical industry, environmental protection, medicine, metal, and power plant desulfurization. The moisture absorption of polypropylene fibers is extremely low, almost non-absorbent. It mainly transfers water vapor through the capillaries in the fabric but does not play any absorption role itself, so filter materials made of polypropylene are particularly prone to accumulating static electricity.

[0004] Conductive carbon powder is a kind of carbon powder with conductive properties, usually made of carbon materials such as carbon black and graphite. Conductive carbon powder has excellent conductive properties and processing properties, and is widely used in the conductive modification of materials such as polyethylene fibers, polypropylene fibers, and non-woven fabrics.

[0005] The main function of conductive carbon powder is to provide conductive properties and make the material conductive. It can be added to the material by compounding or coating with the material, thereby endowing the material with conductive properties. Conductive carbon powder is widely used in fields such as electronics, electrical appliances, and electromagnetic shielding, and is used to manufacture products such as conductive plastics, conductive rubbers, and conductive coatings. When selecting conductive carbon powder, attention should be paid to its performance indicators such as conductive properties, particle size distribution, purity, and stability to ensure that it meets specific application requirements. At the same time, the compatibility and processing properties of conductive carbon powder with other materials also need to be considered to ensure the quality of the final product. Summary of the Invention

[0006] The object of the present invention is to provide a processing method for a polypropylene conductive coating stiffening filter material, which overcomes the dispersion problem of carbon powder and binder, and realizes the integrated processing technology of stiffening the conductive coating of needle-punched polypropylene non-woven fabric by adding a stiffening agent, realizes a good combination of conductive carbon powder and polypropylene non-woven fabric, the product is cured by coating, realizes the folding cylinder processing of the polypropylene conductive filter material, and at the same time endows the filter material with conductive performance.

[0007] To achieve the above object, the present invention provides the following technical solution: A processing method for a polypropylene conductive coating stiffening filter material, comprising the following steps:

[0008] Step S1, according to the processing requirements, prepare needle-punched polypropylene non-woven fabric of corresponding specifications;

[0009] Step S2, prepare a coating mixture containing conductive carbon powder, wherein the particle size of the conductive carbon powder is 18-20 microns;

[0010] Step S3, subject the needle-punched polypropylene non-woven fabric to double dipping and double pressing treatment with the coating mixture, so that the liquid content of the needle-punched polypropylene non-woven fabric is controlled at 80%-105%;

[0011] Step S4, dry the treated needle-punched polypropylene non-woven fabric through a stenter oven, wherein the temperature of the oven is set at 135°C, 165°C, 180°C, 180°C, 180°C, and the speed is set at 10-15 m / min;

[0012] Step S5, trim and wind up the dried needle-punched polypropylene non-woven fabric in step S4 according to requirements, and then carry out PTFE film covering treatment and folding filter cylinder processing to obtain a polypropylene conductive coating stiffening filter material.

[0013] Preferably, the needle-punched polypropylene non-woven fabric in step S1 needs to be strengthened during production, and the specific treatment steps are as follows:

[0014] Step a, pre-needling process: First, it is necessary to carry out preliminary structural integration on the polypropylene fibers of the needle-punched polypropylene non-woven fabric, which is specifically completed through a slight needling process;

[0015] Step b, main needling process: After the pre-needling process is completed, the polypropylene fibers go through the main needling process, specifically, the polypropylene fiber material is further integrated into a dense non-woven fabric structure through a large number of needling actions;

[0016] Step c, hot rolling treatment: After the needle-punched polypropylene non-woven fabric has undergone pre-needling and main needling, the needle-punched polypropylene non-woven fabric is compacted by a hot roller under temperature control conditions.

[0017] Preferably, the polypropylene fiber needle-punched non-woven fabric used in step S1 has a specification of 250-300 g / ㎡, a thickness of 0.8-1.0 mm, and a fiber length of 2.5D×51 mm.

[0018] Preferably, the coating mixture in step S2 contains 800-mesh conductive carbon powder, 25% of clothing adhesive, 15% of acrylic adhesive, 5-8% of anhydrous ethanol dispersant, and 47-50% of water. The particle size of the conductive carbon powder is 18-20 microns. The conductive carbon powder is mixed with the adhesive, and the mass fraction of the conductive carbon powder is 5-8%. The adhesive is an acrylic-based adhesive.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1) Through the composite processing of the needling and impregnation processes, the present invention realizes the processing of polypropylene fiber conductive filter materials and the processing of stiff and foldable polypropylene filter materials.

[0021] 2) In the processing of the present invention, the polypropylene fiber has corrosion-resistant properties and is suitable for filtering high dust in harsh working conditions.

[0022] 3) The composite filter material of the present invention has good conductive and explosion-proof functions, and the surface resistance is about 10^4 ohms. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] Please refer to Figure 1 , the present invention provides a technical solution: a processing method of a polypropylene conductive coating stiff filter material, including the following steps:

[0026] Step S1: Prepare a polypropylene fiber needle-punched non-woven fabric with corresponding specifications according to the processing requirements.

[0027] Step S2: Prepare a coating mixture containing conductive carbon powder, where the particle size of the conductive carbon powder is 18-20 microns.

[0028] Step S3: Subject the polypropylene fiber needle-punched non-woven fabric to double dipping and double pressing treatment with the coating mixture, so that the liquid content of the polypropylene fiber needle-punched non-woven fabric is controlled at 80%-105%.

[0029] Step S4. Dry the treated polypropylene fiber needle-punched nonwoven fabric in a stentering oven, where the oven temperature is set at 135°C, 165°C, 180°C, 180°C, 180°C, and the speed is set at 10 - 15 m / min;

[0030] Step S5. Trim and wind up the dried polypropylene fiber needle-punched nonwoven fabric in Step S4 according to requirements, and then carry out PTFE film coating treatment and corrugated filter cartridge processing to obtain a polypropylene conductive coating stiff filter medium.

[0031] Furthermore, the polypropylene fiber needle-punched nonwoven fabric needs to be strengthened during production in Step S1, and the specific treatment steps are as follows:

[0032] Step a. Pre-needling process: First, the polypropylene fibers of the polypropylene fiber needle-punched nonwoven fabric need to be preliminarily structurally integrated, which is specifically completed through a slight needling process;

[0033] Step b. Main needling process: After the pre-needling process is completed, the polypropylene fibers go through the main needling process, specifically, the polypropylene fiber material is further integrated into a dense non-woven fabric structure through a large number of needling actions;

[0034] Step c. Hot rolling treatment: After the polypropylene fiber needle-punched nonwoven fabric undergoes pre-needling and main needling, the polypropylene fiber needle-punched nonwoven fabric is compacted by a hot roller under temperature control conditions.

[0035] Furthermore, the polypropylene fiber needle-punched nonwoven fabric used in Step S1 has a specification of 250 - 300 g / ㎡, a thickness of 0.8 - 1.0 mm, and a fiber length of 2.5D×51 mm.

[0036] Furthermore, the coating mixture in Step S2 contains 800-mesh conductive carbon powder, 25% clothing adhesive, 15% acrylic adhesive, 5 - 8% anhydrous ethanol dispersant, and 47 - 50% water, where the conductive carbon powder has a particle size of 18 - 20 microns, the conductive carbon powder is mixed with the adhesive, the mass fraction of the conductive carbon powder is 5 - 8%, and the adhesive is an acrylic-based adhesive.

[0037] Specifically, the present invention is further elaborated in combination with embodiments;

[0038] 1) Processing of 350 gsm polypropylene conductive needle-punched filter media; The prepared polypropylene fiber needle-punched nonwoven fabric is successively subjected to opening and cleaning, carding with a gram weight of 40 gsm, 15 layers of web laying, needle-punched processing, a pre-needling density of 80 needles / cm², a main needle one of 150 needles / cm², a main needle two of 150 needles / cm², a main needle three of 180 needles / cm², and a production speed of 4.5 m / min;

[0039] 2) The conductive carbon powder is pretreated with absolute ethanol, mixed with the clothing adhesive and acrylic emulsion, and water is added and stirred for 15 minutes to obtain a conductive carbon powder suspension, and the solid content of the conductive carbon powder suspension is 10-15%;

[0040] 3) The polypropylene fiber needle-punched non-woven fabric is double-dipped and double-rolled with the conductive carbon powder suspension, and then dried at high temperature in a 5-section stenter oven. The oven temperature is 135°C, 165°C, 180°C, 180°C, 180°C, and the oven speed is 10-15 m / min;

[0041] 4) After drying, the edges of the polypropylene fiber needle-punched non-woven fabric are trimmed and wound, PTFE film covering treatment is carried out, and corrugated filter cartridges are processed to obtain the finished 350 gsm polypropylene conductive needle-punched filter material.

[0042] Through the composite processing of the needling and impregnation processes, the present invention realizes the processing of polypropylene fiber conductive filter materials and the processing of stiff and foldable polypropylene filter materials; during the processing, the polypropylene fibers have corrosion-resistant properties and are suitable for filtering high dust in harsh working conditions; this composite filter material has good conductive and explosion-proof functions, and the surface resistance is about 10^4 ohms.

[0043] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A processing method of a polypropylene conductive coating stiff filter material, characterized in that It includes the following steps: Step S1: Prepare the polypropylene fiber needle-punched non-woven fabric with corresponding specifications according to the processing requirements. Step S2: Prepare a coating mixture containing conductive carbon powder, where the particle size of the conductive carbon powder is 18 - 20 microns. Step S3: Subject the polypropylene fiber needle-punched non-woven fabric to double dipping and double pressing treatment with the coating mixture, so that the liquid content of the polypropylene fiber needle-punched non-woven fabric is controlled at 80% - 105%. Step S4: Dry the treated polypropylene fiber needle-punched non-woven fabric through a stenter oven, where the temperature of the oven is set at 135°C, 165°C, 180°C, 180°C, 180°C, and the speed is set at 10 - 15 m / min. Step S5: Trim and wind up the dried polypropylene fiber needle-punched non-woven fabric in Step S4 according to the requirements, and then perform PTFE film covering treatment and corrugated filter cartridge processing to obtain a polypropylene conductive coating stiff filter medium.

2. The processing method of a polypropylene conductive coating stiff filter medium according to claim 1, characterized in that: In Step S1, the polypropylene fiber needle-punched non-woven fabric needs to be strengthened during production. The specific treatment steps are as follows: Step a: Pre-needling process: First, the polypropylene fibers of the polypropylene fiber needle-punched non-woven fabric need to be initially structurally integrated, specifically completed through a slight needling process. Step b: Main needling process: After the pre-needling process is completed, the polypropylene fibers go through the main needling process, specifically, the polypropylene fiber material is further integrated into a dense non-woven fabric structure through a large number of needling actions. Step c: Hot rolling treatment: After the polypropylene fiber needle-punched non-woven fabric undergoes pre-needling and main needling, the polypropylene fiber needle-punched non-woven fabric is compacted by a hot roller under temperature control conditions.

3. The processing method of a polypropylene conductive coating stiff filter material according to claim 1, characterized in that: The polypropylene fiber needle-punched non-woven fabric used in Step S1 has a specification of 250 - 300 g / ㎡, a thickness of 0.8 - 1.0 mm, and a fiber length of 2.5D × 51 mm.

4. The processing method of a polypropylene conductive coating stiff filter material according to claim 1, characterized in that: The coating mixture in Step S2 contains 800-mesh conductive carbon powder, 25% clothing adhesive, 15% acrylic adhesive, 5 - 8% anhydrous ethanol dispersant, and 47 - 50% water. The particle size of the conductive carbon powder is 18 - 20 microns. The conductive carbon powder is mixed with the adhesive, and the mass fraction of the conductive carbon powder is 5 - 8%. The adhesive is an acrylic-based adhesive.

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