Non-asbestos yarn, its manufacturing method and use

Abstract

The application discloses a non-asbestos yarn and a manufacturing method and application thereof. The non-asbestos yarn is spun by using a papermaking method with mineral fibers and cotton pulp and / or waste paper pulp, the mineral fibers are any one or several of sepiolite, brucite and wollastonite, the amount of the mineral fibers is 70-100%, and the amount of the cotton pulp and / or waste paper pulp is 0-30%. The application further provides a manufacturing method of the non-asbestos yarn, the mineral fibers, the cotton pulp and the waste paper pulp are prepared through pulp preparation, papermaking, cutting, twisting and plying. The non-asbestos yarn is used for manufacturing friction materials and sealing materials. The non-asbestos yarn can replace the asbestos yarn, solves the harm caused by traditional asbestos, has simple manufacturing process, convenient operation, avoids environmental pollution, low cost, and is equivalent to the asbestos yarn in ignition loss and tensile strength at room temperature, and can completely replace the asbestos yarn and be used for manufacturing friction materials and sealing materials.

Description

Technical Field

[0001] This invention belongs to the technical field of friction sealing materials, specifically referring to a non-asbestos yarn, its manufacturing method, and its application. Background Technology

[0002] Asbestos, also known as "silica gel," refers to silicate mineral products with high tensile strength, high flexibility, resistance to chemical and thermal erosion, electrical insulation, and spinnability. It is a general term for naturally occurring fibrous silicate minerals. Asbestos is affordable and possesses excellent fire resistance, electrical insulation, and heat insulation properties. For a long time, asbestos was a major raw material in the field of friction sealing materials, such as brake bands, brake pads, packing, and rubber sheets. However, asbestos dust, when inhaled, adheres to and deposits in the lungs, potentially leading to asbestosis, malignant pleural mesothelioma, lung cancer, and other diseases over time. In 2017, the World Health Organization classified asbestos as a Group 1 carcinogen.

[0003] As some countries ban asbestos in more and more fields, scientists are constantly searching for alternative materials. Existing asbestos substitutes mainly include carbon fiber and aramid fiber, but these are too expensive to be used in large quantities for yarn production. A method for preparing sealing materials using such asbestos substitutes typically includes the following steps: 1) The loosened fibers, fillers, color paste, compounding agents, and aluminum sulfate are introduced into a slurry transition tank for circulating slurrying to form a fiber mixture; 2) The circulated slurry is introduced into a first reaction tank, and excess fiber mixture is introduced into a fiber storage tank; 3) Latex is added to the first reaction tank, and the concentration is controlled by a thickener; 4) The slurry from the first reaction tank is pumped into a second reaction tank using a third pump, while aluminum sulfate is added and stirred, and the concentration is controlled by a thickener in the second reaction tank; 5) The stirred slurry from the first reaction tank is pumped into a pre-slurry tank using a fourth pump, and the concentration is controlled by a thickener in the pre-slurry tank. This method of preparing sealing materials using asbestos substitutes also involves the addition of fillers, pigments, compounding agents, aluminum sulfate, and latex, resulting in a complex formula that further increases the cost of preparing sealing materials using asbestos substitutes. The addition of latex also makes the slurry prone to clumping and forming lumps, which is not conducive to the production of slurry films. The entire slurry preparation process is lengthy, cumbersome, and difficult to industrialize. Summary of the Invention

[0004] The purpose of this invention is to provide a non-asbestos yarn, its manufacturing method, and its application, aiming to solve the problems that the price of asbestos yarn substitutes is too high in the prior art, preventing their large-scale use in yarn production, and that existing methods for preparing sealing materials using asbestos substitutes have complex formulations, long processes, cumbersome operations, and are prone to forming lumps, which are not conducive to the production of slurry films.

[0005] To solve the above-mentioned technical problems, the present invention is mainly achieved through the following technical solutions:

[0006] In one aspect, the present invention provides a non-asbestos yarn, wherein the non-asbestos yarn is spun from mineral fibers and cotton pulp and / or waste paper pulp by a papermaking method, wherein the mineral fibers are any one or more of sepiolite, brucite, and wollastonite, and the amount of the mineral fibers is 70-100%, and the amount of the cotton pulp and / or waste paper pulp is 0-30%.

[0007] The non-asbestos yarn of this invention is made from mineral fibers and cotton pulp and / or waste paper pulp. The mineral fibers are sepiolite, brucite, or wollastonite. These mineral fibers have a dense structure and are more environmentally friendly and less polluting than asbestos fibers. Moreover, they are low in cost and can be used on a large scale. This non-asbestos yarn made from mineral fibers and cotton pulp and / or waste paper pulp can replace asbestos yarn, solving the problems caused by traditional asbestos and the yarn it produces. The loss on ignition of this non-asbestos yarn is comparable to that of asbestos yarn, and its tensile strength at room temperature is also comparable to that of asbestos yarn. It can completely replace asbestos yarn and be used to make friction materials and sealing materials.

[0008] In a preferred embodiment, the mineral fiber is a mixture of sepiolite, brucite, and wollastonite in a weight ratio of 3-4:1-2:2-3. The mineral fiber of this invention is a non-asbestos mineral fiber, preferably a water-soluble or hydrophilic mineral fiber, such as sepiolite, brucite, and wollastonite. Sepiolite has excellent overall performance, brucite has good alkali resistance and flame retardancy, and wollastonite has high hardness. This invention can combine sepiolite, brucite, and wollastonite, and through their interaction and mutual promotion, it integrates the advantages of sepiolite, brucite, and wollastonite, further improving the overall performance of the non-asbestos yarn.

[0009] In a preferred embodiment, the amount of mineral fiber is 75-90%, and the amount of cotton pulp and / or waste paper pulp is 10-25%. The non-asbestos yarn of the present invention can be manufactured solely from mineral fiber, or it can be manufactured by mixing mineral fiber with cotton pulp and / or waste paper pulp. Typically, the amount of mineral fiber is 75-90%, and the amount of cotton pulp and / or waste paper pulp is 10-25%. This mixture of mineral fiber and cotton pulp and / or waste paper pulp combines the properties of mineral fiber, cotton pulp, and / or waste paper pulp, further improving the overall performance of the non-asbestos yarn.

[0010] In a preferred embodiment, the ratio of cotton pulp to waste paper pulp is 2:3-4. This invention utilizes both cotton pulp and waste paper pulp in a mixture of mineral fibers and cotton pulp and / or waste paper pulp, comprehensively leveraging the advantages of both to improve their bonding properties, thereby further enhancing the overall performance of the non-asbestos yarn.

[0011] In another aspect, a method for manufacturing a non-asbestos yarn according to the present invention includes the following steps:

[0012] 1) Pulping

[0013] Take mineral fibers, cotton pulp and waste paper pulp, mix them to obtain a fiber mixture; add water and soak for 12-24 hours, the amount of water is 30-50 times the weight of the fiber mixture; use a mechanical pulper to pulp in a circulating manner to disperse the fiber mixture into pulp, add water to dilute, and obtain papermaking pulp with a mass concentration of 1.5-3.5%;

[0014] 2) Papermaking

[0015] The paper pulp obtained in step 1) is transported to a paper pulp tank. A wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film. Long filament fibers are placed on the pulp film at intervals of 0.2-0.5 cm. The pulp film is squeezed and dewatered so that the moisture content of the pulp film does not exceed 60%. It is then dried at 70-110℃ to obtain wet fiber paper with a moisture content not exceeding 50%. The paper is then rolled into rolls.

[0016] 3) Cutting

[0017] Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 5-12mm.

[0018] 4) Twisted thread

[0019] The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 20-50 twists to obtain single yarn;

[0020] 5) Joint venture

[0021] The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

[0022] The method for manufacturing non-asbestos yarn of the present invention first involves soaking mineral fibers, cotton pulp, and waste paper pulp in water and then pulping them. Next, the process involves papermaking, cutting, twisting, and plying to obtain non-asbestos yarn. This papermaking method is a wet spinning process, which generates no dust pollution during manufacturing, avoiding harm to operators and the environment. The process is short, easy to operate, and readily industrialized. Furthermore, the mineral fibers used to replace asbestos fibers are low-cost, and the mineral fibers are organically integrated with cotton pulp and / or waste paper pulp using papermaking methods to obtain a non-asbestos environmentally friendly yarn for use in friction and sealing applications.

[0023] In a preferred embodiment, the filament fiber is any one or more of polyester fiber, acrylic fiber, or nylon fiber. The present invention, by placing filament fibers spaced apart on a slurry film, can improve the strength of non-asbestos yarns. The filament fiber is a tough and high-strength chemical fiber, such as polyester fiber, acrylic fiber, or nylon fiber.

[0024] In a preferred embodiment, in step 2), the moisture content of the pulp film is 50-60%, and the moisture content of the wet fiber paper is 40-50%. In this invention, the moisture content of the pulp film after extrusion dewatering does not exceed 60%, and is typically 50-60%. The pulp film is dewatered by extrusion to form a film, facilitating subsequent processing. Drying is performed on a drying cylinder to remove a certain amount of moisture, forming wet fiber paper. The moisture content of the wet fiber paper does not exceed 50%, and is typically 40-50%. This moisture content of the wet fiber paper facilitates subsequent winding.

[0025] In another aspect, the present invention relates to an application of a non-asbestos yarn used to manufacture friction materials and sealing materials, wherein the friction material is a brake band or brake pad, and the sealing material is packing.

[0026] The non-asbestos yarn of this invention can be used as a substitute for asbestos yarn. Its loss on ignition is comparable to that of asbestos yarn, and its tensile strength at room temperature is also comparable. Therefore, it can completely replace asbestos yarn for the manufacture of friction and sealing materials. Common friction materials include brake bands or brake pads, and common sealing materials include packing. Of course, the mineral fibers of this invention can also directly replace asbestos fibers in the manufacture of rubber sheets.

[0027] In a preferred embodiment, the non-asbestos yarn is a non-asbestos yarn with metal wires, which is obtained by re-twisting the non-asbestos yarn with metal wires. The non-asbestos yarn of the present invention is re-twisted with metal wires to obtain a non-asbestos yarn with metal wires, which is used to directly manufacture non-asbestos brake bands, brake pads, or packing.

[0028] In a preferred embodiment, the non-asbestos yarn with metal wires is woven into a tape, cloth, or rope. The non-asbestos yarn with metal wires of the present invention, after being woven into a tape, cloth, or rope, can be directly used to manufacture non-asbestos brake bands, brake pads, or packing.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: The non-asbestos yarn of the present invention uses non-asbestos mineral fibers as raw materials. These mineral fibers have a dense structure, are dust-free, and are more environmentally friendly and less polluting than asbestos fibers. Moreover, they are low in cost and can be used on a large scale. The non-asbestos mineral fibers are used with cotton pulp and / or waste paper pulp to manufacture non-asbestos yarn, which eliminates dust pollution and avoids harm to operators and the environment. The process is short, easy to operate, and easy to industrialize. The resulting non-asbestos yarn can replace asbestos yarn, solving the hazards caused by traditional asbestos and its resulting yarn. The loss on ignition is comparable to that of asbestos yarn, and the tensile strength at room temperature is also comparable to that of asbestos yarn. It can completely replace asbestos yarn and be used to make friction materials and sealing materials. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The present invention discloses a non-asbestos yarn, wherein the non-asbestos yarn is spun from mineral fibers and cotton pulp and / or waste paper pulp by a papermaking method, wherein the mineral fibers are any one or more of sepiolite, brucite, and wollastonite, and the amount of mineral fibers is 70-100%, and the amount of cotton pulp and / or waste paper pulp is 0-30%.

[0032] Preferably, the mineral fiber is a mixture of sepiolite, brucite and wollastonite in a weight ratio of 3-4:1-2:2-3.

[0033] Preferably, the amount of mineral fiber used is 75-90%, and the amount of cotton pulp and / or waste paper pulp used is 10-25%.

[0034] Furthermore, the ratio of the cotton pulp to the waste paper pulp is 2:3-4.

[0035] A method for manufacturing non-asbestos yarn according to the present invention includes the following steps:

[0036] 1) Pulping

[0037] Take mineral fibers, cotton pulp and waste paper pulp, mix them to obtain a fiber mixture; add water and soak for 12-24 hours, the amount of water is 30-50 times the weight of the fiber mixture; use a mechanical pulper to pulp in a circulating manner to disperse the fiber mixture into pulp, add water to dilute, and obtain papermaking pulp with a mass concentration of 1.5-3.5%;

[0038] 2) Papermaking

[0039] The paper pulp obtained in step 1) is transported to a paper pulp tank. A wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film. Long filament fibers are placed on the pulp film at intervals of 0.2-0.5 cm. The pulp film is squeezed and dewatered so that the moisture content of the pulp film does not exceed 60%. It is then dried at 70-110℃ to obtain wet fiber paper with a moisture content not exceeding 50%. The paper is then rolled into rolls.

[0040] 3) Cutting

[0041] Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 5-12mm.

[0042] 4) Twisted thread

[0043] The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 20-50 twists to obtain single yarn;

[0044] 5) Joint venture

[0045] The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

[0046] Preferably, the filament fiber is any one or more of polyester fiber, acrylic fiber or nylon fiber.

[0047] Preferably, in step 2), the moisture content of the pulp film is 50-60%, and the moisture content of the wet fiber paper is 40-50%.

[0048] The present invention relates to an application of a non-asbestos yarn, wherein the non-asbestos yarn is used to make friction materials and sealing materials, wherein the friction material is a brake band or brake pad, and the sealing material is packing.

[0049] Preferably, the non-asbestos yarn is a non-asbestos yarn with metal wires, which is obtained by twisting the non-asbestos yarn and the metal wires together.

[0050] Preferably, the non-asbestos yarn with metal wires is woven into a belt, cloth, or rope.

[0051] Example 1

[0052] A method for manufacturing non-asbestos yarn according to the present invention includes the following steps:

[0053] 1) Pulping

[0054] Take 100 kg of mineral fiber—sepiolite, add water, and soak for 24 hours. The amount of water is 30 times the weight of the mineral fiber. Use a mechanical pulper to pulp in a circulating manner to disperse the mineral fiber into pulp. Dilute with water to obtain paper pulp with a mass concentration of 3.5%.

[0055] 2) Papermaking

[0056] The paper pulp obtained in step 1) is transported to a paper pulp tank, and a wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film; long filament fibers—polyester fibers—are placed on the pulp film at intervals of 5 mm; the pulp film is squeezed and dewatered to a moisture content of 60%; it is then dried in a drying cylinder at 110°C to obtain wet fiber paper with a moisture content of 50%; and finally rolled into rolls.

[0057] 3) Cutting

[0058] Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 12mm.

[0059] 4) Twisted thread

[0060] The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 40 twists to obtain single yarn;

[0061] 5) Joint venture

[0062] The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

[0063] Example 2

[0064] A method for manufacturing non-asbestos yarn according to the present invention includes the following steps:

[0065] 1) Pulping

[0066] Take 70 kg of mineral fiber—sepiolite—and 30 kg of cotton pulp, mix them to obtain a fiber mixture; add water and soak for 12 hours, the amount of water being 50 times the weight of the fiber mixture; use a mechanical pulper to pulp in a circulating manner to disperse the fiber mixture into pulp, dilute with water to obtain paper pulp with a mass concentration of 1.5%;

[0067] 2) Papermaking

[0068] The paper pulp obtained in step 1) is transported to a paper pulp tank, and a wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film; long filament fibers—acrylic fibers—are placed on the pulp film at intervals of 2 mm; the pulp film is squeezed and dewatered to a moisture content of 50%; it is then dried in a drying cylinder at 70°C to obtain wet fiber paper with a moisture content of 40%; and finally rolled into rolls.

[0069] 3) Cutting

[0070] Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 5 mm.

[0071] 4) Twisted thread

[0072] The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 50 twists to obtain single yarn;

[0073] 5) Joint venture

[0074] The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

[0075] Example 3

[0076] A method for manufacturing non-asbestos yarn according to the present invention includes the following steps:

[0077] 1) Pulping

[0078] Take 45 kg of mineral fibers—sepiolite and 45 kg of magnesia, 10 kg of cotton pulp and 20 kg of waste paper pulp, mix them to obtain a fiber mixture; add water and soak for 20 hours, the amount of water being 40 times the weight of the fiber mixture; use a mechanical pulper to pulp in a circulating manner to disperse the fiber mixture into pulp, dilute with water to obtain paper pulp with a mass concentration of 2.5%;

[0079] 2) Papermaking

[0080] The paper pulp obtained in step 1) is transported to a paper pulp tank, and a wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film; long filament fibers—nylon fibers—are placed on the pulp film at intervals of 5 mm; the pulp film is squeezed and dewatered to a moisture content of 55%; it is then dried in a drying cylinder at 100°C to obtain wet fiber paper with a moisture content of 45%; and finally rolled into rolls.

[0081] 3) Cutting

[0082] Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 10mm.

[0083] 4) Twisted thread

[0084] The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 40 twists to obtain single yarn;

[0085] 5) Joint venture

[0086] The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

[0087] Example 4

[0088] A method for manufacturing non-asbestos yarn according to the present invention includes the following steps:

[0089] 1) Pulping

[0090] Take 60 kg of sepiolite, 20 kg of magnesia, 40 kg of wollastonite and 40 kg of waste paper pulp, mix them to obtain a fiber mixture; add water and soak for 18 hours, the amount of water is 35 times the weight of the fiber mixture; use a mechanical pulper to pulp in a circulating manner to disperse the fiber mixture into pulp, dilute with water to obtain paper pulp with a mass concentration of 2.0%;

[0091] 2) Papermaking

[0092] The paper pulp obtained in step 1) is transported to a paper pulp tank, and a wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film; long filament fibers—polyester fibers—are placed on the pulp film at intervals of 4 mm; the pulp film is squeezed and dewatered to a moisture content of 53%; it is then dried in a drying cylinder at 90°C to obtain wet fiber paper with a moisture content of 46%; and finally rolled into rolls.

[0093] 3) Cutting

[0094] Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 8mm.

[0095] 4) Twisted thread

[0096] The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 45 twists to obtain single yarn;

[0097] 5) Joint venture

[0098] The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

[0099] Example 5

[0100] A method for manufacturing non-asbestos yarn according to the present invention includes the following steps:

[0101] 1) Pulping

[0102] Take 40 kg of sepiolite, 20 kg of magnesia, 30 kg of wollastonite, 4 kg of cotton pulp and 6 kg of waste paper pulp, mix them to obtain a fiber mixture; add water and soak for 22 hours, the amount of water is 45 times the weight of the fiber mixture; use a mechanical pulper to pulp in a circulating manner to disperse the fiber mixture into pulp, dilute with water to obtain paper pulp with a mass concentration of 3.0%;

[0103] 2) Papermaking

[0104] The paper pulp obtained in step 1) is transported to a paper pulp tank, and a wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film; long filament fibers—polyester fibers—are placed on the pulp film at intervals of 3 mm; the pulp film is squeezed and dewatered to a moisture content of 58%; it is then dried in an 80°C drying cylinder to obtain wet fiber paper with a moisture content of 42%; and finally rolled into rolls.

[0105] 3) Cutting

[0106] Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 8mm.

[0107] 4) Twisted thread

[0108] The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 20 twists to obtain single yarn;

[0109] 5) Joint venture

[0110] The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

[0111] Comparative Example 1

[0112] Existing asbestos yarn was used as a control sample. The production method of existing asbestos yarn is as described in Chinese Patent CN1127312A.

[0113] Comparative Example 2

[0114] Sepiolite was taken and pulped using the method described in Chinese Patent CN106906683A. The paper was then formed, cut, twisted, and plied using the method described in Example 5 of this invention to obtain non-asbestos yarn, which served as control sample 2.

[0115] Comparative Example 3

[0116] Asbestos fibers were taken and pulped with cotton pulp and waste paper pulp according to the method of Example 5 of this invention. The pulping process was continued, including papermaking, cutting, twisting and plying, to obtain non-asbestos yarn, which served as control sample 3.

[0117] Five samples of non-asbestos yarn obtained from Examples 1 to 5, as well as control sample 1 from Comparative Example 1, control sample 2 from Comparative Example 2, and control sample 3 from Comparative Example 3, were taken and their loss on ignition and tensile strength at room temperature were determined. The loss on ignition was determined according to the method specified in the People's Republic of China Building Materials Industry Standard JC / T221-2009. Tensile strength was determined using a Y361-30 tensile testing instrument manufactured by Changzhou Second Textile Machinery Co., Ltd. The unit weight of the tested sample was approximately 2.0 g / m. The experimental results are listed in Table 1.

[0118] Table 1. Test results of different yarn properties

[0119] Sample Name Loss on ignition (%) Tensile strength (N) Unit weight (g / m³) Example 1 13 16 2.0 Example 2 35 24 1.8 Example 3 28 20 2.2 Example 4 29 24 1.8 Example 5 22 30 1.8 Control Sample 1 16-35 9-22 1.9 Control Sample 2 16 17 2.2 Control Sample 3 23 26 1.8

[0120] Regarding loss on ignition (LOI), a lower LOI indicates better fire resistance, and the yarn is more resistant to LOI. According to the People's Republic of China Building Materials Industry Standard JC / T221-2009, asbestos yarn is classified into six grades based on LOI: Grade S has a LOI of 32.1-35.0%, Grade B has a LOI of 28.1-32.0%, Grade A has a LOI of 24.1-28.0%, Grade AA has a LOI of 19.1-24.0%, Grade AAA has a LOI of 16.1-19.0%, and Grade AAAA has a LOI not exceeding 16%. As shown in Table 1, the loss on ignition (LOI) of the non-asbestos yarn obtained by the method of the present invention is between 13% and 35%, which is within the range of the LOI variation of existing asbestos yarn, i.e., control sample 1. Therefore, the LOI of the non-asbestos yarn obtained by the method of the present invention is comparable to that of existing asbestos yarn. In Example 1, since it contains only mineral fibers and no cotton pulp or paper pulp, the LOI is particularly good, at 13%, reaching the LOI of AAAA grade asbestos yarn. In Example 2, since the amount of mineral fibers is small and the amount of cotton pulp is large, the LOI is the largest, at 35%, reaching the LOI of S grade asbestos yarn. In Examples 3 and 4, the amount of mineral fibers is large and the amount of cotton pulp and / or waste paper pulp is moderate, resulting in moderate LOI, reaching the LOI of B grade asbestos yarn. In Example 5, the amount of mineral fibers is relatively large and the amount of cotton pulp and waste paper pulp is appropriate, resulting in good LOI, reaching the LOI of AA grade asbestos yarn. Of course, by adjusting the amount of mineral fiber, cotton pulp, and / or waste paper pulp, it is possible to obtain asbestos yarns with loss on ignition (LOI) comparable to other grades. While the LOI of Control Sample 2 is close to that of Example 1, it involves the addition of fillers, color paste, compounding agents, aluminum sulfate, and latex during the pulping process. This results in a complex formula, high cost, and the addition of latex can cause the pulp to clump, forming lumps that are unfavorable for film production. The entire pulping process is lengthy, cumbersome, and difficult to industrialize. The LOI of Control Sample 3 is consistent with that of Example 5 of this invention; however, Control Sample 3 also suffers from problems such as high dust levels, significant environmental pollution, and health hazards during its manufacturing process.

[0121] Regarding tensile strength, higher tensile strength indicates better tensile properties and greater yarn processing resistance. Table 1 also shows that the tensile strength of the non-asbestos yarn obtained by the method of this invention is between 16-30 N / g, which is within the range of tensile strength variation of existing asbestos yarn, i.e., control sample 1. Therefore, the tensile strength of the non-asbestos yarn obtained by the method of this invention at room temperature is comparable to that of existing asbestos yarn at room temperature. Specifically, in Example 1, due to the presence of only short fibers, the tensile strength is low, but it still meets the requirements for subsequent processing. The tensile strengths of Examples 2 to 4 are all around 22 N, which is the result of the combined effect of mineral fibers, cotton pulp, and / or waste paper pulp. Example 5 has the highest tensile strength, reaching 30 N, which is the result of optimized proportions of mineral fibers, cotton pulp, and / or waste paper pulp. Control sample 2 has a lower tensile strength due to the unfavorable conditions for pulp film formation during the pulping process; similar to Example 1, its tensile strength is only 17 N / g. The tensile strength of control sample 3 was 26 N, which is the result of the combined effect of asbestos fibers, cotton pulp, and / or waste paper pulp.

[0122] Therefore, compared with the prior art, the beneficial effects of the present invention are as follows: The non-asbestos yarn of the present invention uses non-asbestos mineral fibers as raw materials. These mineral fibers have a dense structure, are dust-free, and are more environmentally friendly and less polluting than asbestos fibers. Moreover, they are low in cost and can be used on a large scale. The non-asbestos mineral fibers are used with cotton pulp and / or waste paper pulp to manufacture non-asbestos yarn, which eliminates dust pollution and avoids harm to operators and the environment. The process is short, easy to operate, and easy to industrialize. The resulting non-asbestos yarn can replace asbestos yarn, solving the hazards caused by traditional asbestos and its resulting yarn. The loss on ignition is comparable to that of asbestos yarn, and the tensile strength at room temperature is also comparable to that of asbestos yarn. It can completely replace asbestos yarn and be used to make friction materials and sealing materials.

[0123] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for manufacturing brake bands or packing using non-asbestos yarn, characterized in that: The brake band or packing is made of non-asbestos yarn with metal wires. The non-asbestos yarn with metal wires is woven into a band, cloth or rope. The non-asbestos yarn with metal wires is obtained by twisting non-asbestos yarn and metal wires together. The non-asbestos yarn is spun from mineral fibers, cotton pulp, and waste paper pulp using a papermaking method. The mineral fibers are a mixture of sepiolite, magnesia, and wollastonite in a weight ratio of 3-4:1-2:2-3, with the mineral fibers accounting for 75-90% of the yarn. The cotton pulp and waste paper pulp account for 10-25% of the yarn, and the ratio of the cotton pulp to the waste paper pulp is 2:3-4. The method for manufacturing the non-asbestos yarn includes the following steps: 1) Pulping Take mineral fibers, cotton pulp and waste paper pulp, mix them to obtain a fiber mixture; add water and soak for 12-24 hours, the amount of water is 30-50 times the weight of the fiber mixture; use a mechanical pulper to pulp in a circulating manner to disperse the fiber mixture into pulp, add water to dilute, and obtain paper pulp with a mass concentration of 1.5-3.5%; 2) Papermaking The paper pulp obtained in step 1) is transported to a paper pulp tank. A wire mesh is used to adsorb the paper pulp suspended in water onto the wire mesh to form a pulp film. Long filament fibers are placed on the pulp film at intervals of 0.2-0.5 cm. The pulp film is squeezed and dewatered so that the moisture content of the pulp film does not exceed 60%. It is then dried at 70-110℃ to obtain wet fiber paper with a moisture content not exceeding 50%. The paper is then rolled into rolls. 3) Cutting Cut the roll of wet fiber paper obtained in step 2) into strips with a width of 5-12mm. 4) Twisted thread The paper strips obtained in step 3) are twisted into yarn using a twisting machine with a twist of 20-50 twists to obtain single yarn; 5) Joint venture The single yarn obtained in step 4) is retwisted using a retwisting machine to obtain non-asbestos yarn.

2. The method for making brake bands or packing using non-asbestos yarn according to claim 1, characterized in that: The filament fiber is any one or more of polyester fiber, acrylic fiber, or nylon fiber.

3. The method for making brake bands or packing using non-asbestos yarn according to claim 2, characterized in that: In step 2), the moisture content of the pulp film is 50-60%, and the moisture content of the wet fiber paper is 40-50%.