Easy-clean industrial noise-reducing earmuffs

Abstract

The application discloses an easy-to-clean industrial noise reduction earmuff and belongs to the technical field of earmuffs. The earmuff comprises an earmuff main body and an ear pad arranged on the earmuff main body, and the ear pad is composed of a flexible base material and a fabric layer wrapped on the outer surface of the flexible base material. The fabric layer is prepared through a specific process: the fabric is immersed in a treatment liquid, and then cross-linked and dried to obtain the fabric layer. The treatment liquid comprises 5-10% of polyacrylic acid, 3-8% of nanocellulose, 0.3-0.7% of a cross-linking agent, 0.1-0.5% of an additive and the balance of deionized water. The industrial noise reduction earmuff prepared by the application has the characteristics of easy cleaning, can effectively block the penetration of sweat and significantly improves the sanitary safety, wearing comfort and service life of the earmuff.

Description

Technical Field

[0001] This invention belongs to the field of earmuff technology and relates to an easy-to-clean industrial noise-reducing earmuff. Background Technology

[0002] In modern industrial production environments, noise pollution has become one of the major threats to the occupational health of workers. According to industrial hygiene research data, noise levels in production sites of industries such as machining, metallurgy, construction, and aerospace often reach 90-120 decibels, far exceeding the national occupational exposure limit of 85 decibels. Long-term exposure to such high-noise environments can lead not only to increased hearing threshold, tinnitus, and hearing fatigue, but also to systemic health problems such as neurasthenia, cardiovascular disease, and endocrine disorders, seriously affecting workers' work efficiency and quality of life. Therefore, industrial noise-canceling earmuffs, as a type of personal protective equipment that effectively reduces environmental noise and protects hearing, are widely used in various industrial settings and have become a key protective measure for ensuring occupational health and safety.

[0003] Currently, industrial noise-canceling earmuffs on the market typically consist of the following core components: a rigid outer shell, often made of high-strength engineering plastics such as ABS and polycarbonate, which serves to block external sound waves from directly entering; sound-absorbing materials filling the inner shell, commonly including high-density polyurethane foam, fiberglass cotton, and sound-absorbing cotton, which absorb sound wave energy through a porous structure; and ear pads that come into contact with the human ear, which are usually multi-layered composites, with the core substrate generally being silicone or foam, and the surface typically covered with a fabric layer (such as polyester fiber, nylon, etc.). Some products add a thin layer between the substrate and the fabric layer to enhance sealing.

[0004] In daily use, the fabric layer on the surface of the earpads is in direct contact with the skin and the external environment, making it the primary target for cleaning. However, during prolonged industrial work, the area around the ears secretes a large amount of sweat, which is quickly absorbed by the fabric layer. Due to the loose fiber structure of the fabric layer, sweat seeps into the gaps between the fibers, leaving behind salt, oil, and other substances that can breed bacteria and produce an unpleasant odor. More importantly, over long-term use, sweat may penetrate through the fabric layer into the internal silicone or sponge substrate. Since the internal silicone or sponge substrate is encased in the fabric layer, it cannot be cleaned as easily as the surface fabric layer. Once contaminated, this not only seriously affects the user's health but also significantly reduces wearing comfort and the lifespan of the earpads. Summary of the Invention

[0005] The purpose of this invention is to provide an easy-to-clean industrial noise-canceling earmuff, effectively solving the problems of existing earmuffs being easily contaminated by sweat and difficult to clean.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] An easy-to-clean industrial noise-canceling earmuff includes an earmuff body and an ear pad disposed on the earmuff body. The ear pad includes a flexible substrate and a fabric layer wrapped around the outer surface of the flexible substrate. The fabric layer is prepared by immersing the fabric in a treatment solution, cross-linking it first, and then drying it to obtain the fabric layer.

[0008] The treatment liquid comprises the following raw materials by weight percentage:

[0009] Polyacrylic acid 5%-10%

[0010] Nanocellulose 3%-8%

[0011] Crosslinking agent 0.3-0.7%

[0012] Additives 0.1-0.5%

[0013] The remainder is deionized water.

[0014] Preferably, the additive is graphene oxide.

[0015] Preferably, the crosslinking agent is glutaraldehyde.

[0016] It needs to be explained that glutaraldehyde forms a Schiff base by reacting the dialdehyde group in the molecule with a small amount of carboxyl groups in polyacrylic acid, forms an acetal bond with the hydroxyl groups of nanocellulose, and simultaneously interacts with the hydroxyl or carboxyl groups on the surface of graphene oxide through covalent or non-covalent interactions to construct a three-dimensional cross-linked network.

[0017] It is important to emphasize that glutaraldehyde only crosslinks with a small number of carboxyl groups of polyacrylic acid, retaining most of the carboxyl groups. This allows it to regulate the shrinkage and swelling of polyacrylic acid segments through protonation or deprotonation in different pH environments (such as acidic sweat or neutral cleaning solutions).

[0018] Preferably, the fabric is selected from at least one of polyester fiber fabric, nylon fabric or cotton fabric.

[0019] Preferably, the bath ratio of the fabric mass to the treatment liquid volume is 1g:10-20mL.

[0020] Preferably, the immersion temperature of the fabric is 20-30°C, and the immersion time of the fabric is 10-30 minutes.

[0021] Preferably, the crosslinking temperature of the fabric is 40-60°C, and the crosslinking time of the fabric is 30-60 minutes.

[0022] Preferably, the drying temperature of the fabric is 60-80℃, and the drying time of the fabric is 10-20 minutes.

[0023] Preferably, the flexible substrate is silicone or polyurethane foam, and the surface of the flexible substrate is hydrophobically treated.

[0024] The beneficial effects of this invention are:

[0025] A smart fabric layer with a dual-response mechanism was constructed by compounding polyacrylic acid (PAA) and cellulose nanofiber (CNF) in a treatment solution and introducing graphene oxide (GO) as an auxiliary agent. The carboxyl groups in the PAA molecular chain deprotonate in a neutral or alkaline environment (-COO). - In the presence of -COO, the molecular chains extend due to electrostatic repulsion, maintaining the high porosity of the fabric layer; however, in an acidic sweat environment, -COO - Group-bound protons (H) + The GO group is converted to the -COOH form (protonation). The molecular chains shrink due to the loss of electrostatic repulsion, simultaneously triggering the rapid contraction of CNF nanopores due to the Donnan effect. Ion channels between GO sheets accelerate electrolyte diffusion, amplifying the contraction effect through concentration gradients. This causes a sharp drop in the fabric layer's porosity, achieving rapid sealing during sweating and effectively preventing sweat and its carried salts and oils from penetrating into the flexible substrate. In neutral or alkaline washing environments, the carboxyl groups deprotonate, converting to -COO. - This process, involving molecular chain swelling and increased GO layer spacing, combined with CNF nanopore restoration, increases fabric porosity to restore breathability. At this point, salt, oil, and other stains from sweat are more easily removed from the fiber surface due to the relaxed fabric structure, requiring only simple wiping or short washing to remove them, significantly reducing cleaning difficulty. Simultaneously, because sweat and its stains cannot penetrate deep into the fabric and flexible substrate, it reduces the problem of lingering odors or incomplete cleaning after repeated washing, as is common with traditional earmuffs, significantly improving cleaning efficiency and effectiveness.

[0026] The hydrophobic treatment on the surface of the flexible substrate further blocks the penetration path, which works synergistically with the dual-response function of the fabric layer to significantly improve the earmuff's ease of cleaning, hygiene and safety, and wearing comfort while maintaining excellent noise reduction performance. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0028] Example 1

[0029] An easy-to-clean industrial noise-canceling earmuff comprises an earmuff body and ear pads, with the ear pads symmetrically positioned on the earmuff body. The earmuff body is made of ABS engineering plastic, and its interior is filled with high-density polyurethane foam as a sound-absorbing material, effectively absorbing external sound waves. The ear pads are the key component for achieving the easy-to-clean function, comprising a flexible substrate and a fabric layer wrapped around its outer surface. The flexible substrate is made of silicone, and its surface undergoes a hydrophobic treatment before use. Specifically, the silicone is immersed in a 5% fluorosilane solution for 1 hour, then dried at 80°C for 2 hours to form a hydrophobic layer. After this treatment, the contact angle of the silicone surface reaches 112±3° (measured according to GB / T 30693-2014 standard), thus blocking the penetration path of sweat.

[0030] The treatment fluid comprises the following raw materials by weight percentage, as shown in Table 1.

[0031] Table 1

[0032]

[0033] The specific preparation method of the treatment solution is as follows:

[0034] S1. Weigh out polyacrylic acid, nanocellulose, crosslinking agent (glutaraldehyde), auxiliary agent (graphene oxide) and deionized water according to the proportion, wherein the deionized water is divided into three parts;

[0035] S2. Pour the first part of deionized water into container a, turn on the magnetic stirrer and stir at 300 r / min. Then slowly add polyacrylic acid into container a and stir until it is initially dispersed.

[0036] S3. Add nanocellulose in small amounts multiple times, stirring until basically dispersed after each addition. The total stirring time is about 30 minutes, during which the speed is increased to 400r / min.

[0037] S4. Mix the second part of water and ethanol at a volume ratio of 1:1 to form an ethanol-water solution. Dissolve the crosslinking agent in the ethanol-water solution and pour it into container a. Continue stirring for 15 minutes.

[0038] S5. Disperse the additives by ultrasonication (200W, 15 minutes) in the third part of deionized water and pour it into container a. Continue stirring until the system is evenly mixed. Finally, transfer the treatment solution to a sealed container for later use.

[0039] The specific steps for fabric layer treatment are as follows:

[0040] Y1. Select polyester fiber fabric, cut it into 20cm×20cm square pieces, soak it in deionized water for 10 minutes to remove impurities, and then drain the water.

[0041] Y2. Pour the treatment solution into a rectangular plastic container, add the pretreated fabric at a liquor ratio of 1:15 (g / mL), and ensure complete immersion; immerse at 25°C for 20 minutes, turning the fabric every 5 minutes during this period.

[0042] Y3. Remove the soaked fabric, squeeze out the excess treatment solution, rinse the fabric twice with deionized water to remove residual ethanol, drain the water, lay it flat on a petri dish, and place it in an oven preheated to 50°C for crosslinking for 45 minutes.

[0043] Y4. Remove the cross-linked fabric layer from the oven and immediately transfer it to a 0.1M glycine solution. Soak it at room temperature for 12 minutes to quench unreacted glutaraldehyde active groups. Then rinse it with deionized water 4 times (3 minutes each time), replacing the water with fresh deionized water each time, to thoroughly remove residual glycine and cross-linking byproducts.

[0044] Y5. After quenching, the fabric is transferred to a 70℃ drying oven and dried for 15 minutes to obtain the fabric layer.

[0045] The ear pad assembly is as follows: The hydrophobic treated flexible substrate is cut to fit the ear cup body. A hot pressing process is used to hot press the fabric layer tightly wrapped and fixed on the flexible substrate for 5 minutes at a temperature of 100℃ and a pressure of 0.3MPa, thus completing the ear pad preparation.

[0046] Example 2

[0047] An easy-to-clean industrial noise-canceling earmuff comprises an earmuff body and ear pads, with the ear pads symmetrically positioned on the earmuff body. The earmuff body is made of ABS engineering plastic, and its interior is filled with high-density polyurethane foam as a sound-absorbing material, effectively absorbing external sound waves. The ear pads are the key component for achieving the easy-to-clean function, comprising a flexible substrate and a fabric layer wrapped around its outer surface. The flexible substrate is made of silicone, and its surface undergoes a hydrophobic treatment before use. Specifically, the silicone is immersed in a 5% fluorosilane solution for 1 hour, then dried at 80°C for 2 hours to form a hydrophobic layer. After this treatment, the contact angle of the silicone surface reaches 112±3° (measured according to GB / T 30693-2014 standard), thus blocking the penetration path of sweat.

[0048] The treatment solution comprises the following raw materials by weight percentage, as shown in Table 2.

[0049] Table 2

[0050]

[0051] The specific preparation method of the treatment solution is as follows:

[0052] S1. Weigh out polyacrylic acid, nanocellulose, crosslinking agent (glutaraldehyde), auxiliary agent (graphene oxide) and deionized water according to the proportion, wherein the deionized water is divided into three parts;

[0053] S2. Pour the first part of deionized water into container a, turn on the magnetic stirrer and stir at 280 r / min. Then slowly add polyacrylic acid into container a and stir until it is initially dispersed.

[0054] S3. Add nanocellulose in small amounts multiple times, stirring until basically dispersed after each addition. The total stirring time is about 25 minutes, during which the speed is increased to 380r / min.

[0055] S4. Mix the second part of water and ethanol at a volume ratio of 1:1 to form an ethanol-water solution. Dissolve the crosslinking agent in the ethanol-water solution and pour it into container a. Continue stirring for 12 minutes.

[0056] S5. Disperse the additives by ultrasound (180W, 12 minutes) in the third part of deionized water and pour it into container a. Continue stirring until the system is evenly mixed. Finally, transfer the treated liquid to a sealed container for later use.

[0057] The specific steps for fabric layer treatment are as follows:

[0058] Y1. Select polyester fiber fabric, cut it into 20cm×20cm square pieces, soak it in deionized water for 10 minutes to remove impurities, and then drain the water.

[0059] Y2. Pour the treatment solution into a rectangular plastic container, add the pretreated fabric at a liquor ratio of 1:10 (g / mL), and ensure complete immersion; immerse at 20°C for 10 minutes, turning the fabric every 4 minutes during this period.

[0060] Y3. Take out the soaked fabric, squeeze out the excess treatment liquid, rinse the fabric twice with deionized water to remove residual ethanol, drain the water, lay it flat on a petri dish, and put it in an oven preheated to 40°C for crosslinking for 30 minutes.

[0061] Y4. Remove the cross-linked fabric layer from the oven and immediately transfer it to a 0.1M glycine solution. Soak it at room temperature for 12 minutes to quench unreacted glutaraldehyde active groups. Then rinse it with deionized water 4 times (3 minutes each time), replacing the water with fresh deionized water each time, to thoroughly remove residual glycine and cross-linking byproducts.

[0062] Y5. After quenching, the fabric is transferred to a 60℃ drying oven and dried for 10 minutes to obtain the fabric layer.

[0063] The ear pad assembly is as follows: The hydrophobic treated flexible substrate is cut to fit the earmuff body. A hot pressing process is used to hot press for 5 minutes at a temperature of 100℃ and a pressure of 0.3MPa to tightly wrap and fix the fabric layer on the flexible substrate, thus completing the earmuff preparation.

[0064] Example 3

[0065] An easy-to-clean industrial noise-canceling earmuff comprises an earmuff body and ear pads, with the ear pads symmetrically positioned on the earmuff body. The earmuff body is made of ABS engineering plastic, and its interior is filled with high-density polyurethane foam as a sound-absorbing material, effectively absorbing external sound waves. The ear pads are the key component for achieving the easy-to-clean function, comprising a flexible substrate and a fabric layer wrapped around its outer surface. The flexible substrate is made of silicone, and its surface undergoes a hydrophobic treatment before use. Specifically, the silicone is immersed in a 5% fluorosilane solution for 1 hour, then dried at 80°C for 2 hours to form a hydrophobic layer. After this treatment, the contact angle of the silicone surface reaches 112±3° (measured according to GB / T 30693-2014 standard), thus blocking the penetration path of sweat.

[0066] The treatment fluid comprises the following raw materials by weight percentage, as shown in Table 3.

[0067] Table 3

[0068]

[0069] The specific preparation method of the treatment solution is as follows:

[0070] S1. Weigh out polyacrylic acid, nanocellulose, crosslinking agent (glutaraldehyde), auxiliary agent (graphene oxide) and deionized water according to the proportion, wherein the deionized water is divided into three parts;

[0071] S2. Pour the first part of deionized water into container a, turn on the magnetic stirrer and stir at 320 r / min. Then slowly add polyacrylic acid into container a and stir until it is initially dispersed.

[0072] S3. Add nanocellulose in small amounts multiple times, stirring until basically dispersed after each addition. The total stirring time is about 32 minutes, during which the speed is increased to 420r / min.

[0073] S4. Mix the second part of water and ethanol at a volume ratio of 1:1 to form an ethanol-water solution. Dissolve the crosslinking agent in the ethanol-water solution and pour it into container a. Continue stirring for 18 minutes.

[0074] S5. Disperse the additives by ultrasound (220W, 18 minutes) in the third part of deionized water and pour it into container a. Continue stirring until the system is evenly mixed. Finally, transfer the treated solution to a sealed container for later use.

[0075] The specific steps for fabric layer treatment are as follows:

[0076] Y1. Select polyester fiber fabric, cut it into 20cm×20cm square pieces, soak it in deionized water for 10 minutes to remove impurities, and then drain the water.

[0077] Y2. Pour the treatment solution into a rectangular plastic container, add the pretreated fabric at a liquor ratio of 1:20 (g / mL), and ensure complete immersion; immerse at 30°C for 30 minutes, turning the fabric every 6 minutes during this period.

[0078] Y3. Take out the soaked fabric, squeeze out the excess treatment solution, rinse the fabric twice with deionized water to remove residual ethanol, drain the water, lay it flat on a petri dish, and put it in an oven preheated to 60°C for crosslinking for 60 minutes.

[0079] Y4. Remove the cross-linked fabric layer from the oven and immediately transfer it to a 0.1M glycine solution. Soak it at room temperature for 12 minutes to quench unreacted glutaraldehyde active groups. Then rinse it with deionized water 4 times (3 minutes each time), replacing the water with fresh deionized water each time, to thoroughly remove residual glycine and cross-linking byproducts.

[0080] Y5. After quenching, the fabric is transferred to an 80℃ drying oven and dried for 20 minutes to obtain the fabric layer.

[0081] The ear pad assembly is as follows: The hydrophobic treated flexible substrate is cut to fit the earmuff body. A hot pressing process is used to hot press for 5 minutes at a temperature of 100℃ and a pressure of 0.3MPa to tightly wrap and fix the fabric layer on the flexible substrate, thus completing the earmuff preparation.

[0082] Comparative Example 1

[0083] The difference from Example 1 is that the polyester fiber fabric is not treated with the treatment solution.

[0084] Comparative Example 2

[0085] The difference from Example 1 is that no nanocellulose is added to the treatment solution formulation.

[0086] Comparative Example 3

[0087] The difference from Example 1 is that graphene oxide is not added to the treatment solution formulation.

[0088] Comparative Example 4

[0089] The difference from Example 1 is that the flexible substrate was not treated with hydrophobicity.

[0090] Test Example 1

[0091] Sweat permeability test:

[0092] Methods: Three earmuff samples from each embodiment and comparative example were equilibrated for 24 hours at (23±2)℃ and (50±5)%RH. During testing, the initial mass of the flexible substrate of the ear pad was first weighed. Then, the sample was fixed onto a support simulating the ear contour, ensuring a tight fit between the ear pad fabric layer and the substrate. 10g of artificial sweat (pH=5.5, containing 0.5% NaCl, 0.5% lactic acid, and 0.1% urea) was evenly dripped onto the surface of the fabric layer, and timing was immediately initiated. The sample was placed in a constant temperature and humidity chamber at (37±1)℃ and (65±5)%RH for 30 minutes. After removal, residual sweat was gently wiped off with medical absorbent cotton. The ear pad was then disassembled to separate the fabric layer from the flexible substrate, and the mass of the flexible substrate was weighed again.

[0093] Evaluation: The permeation amount is calculated based on the mass difference between the two weighings (permeation amount = second mass - initial mass), and then the permeation rate is calculated (permeation rate = permeation amount / initial sweat mass × 100%). The average value of 3 tests is taken for each sample to evaluate the ear pad's ability to block sweat.

[0094] Test Example 2

[0095] Breathability recovery test:

[0096] Method: Circular samples with a diameter of 50 mm were cut from the ear pad fabric layers of each embodiment and comparative example, and equilibrated for 24 hours in an environment of (23±2)℃ and (50±5)%RH. According to GB / T5453-1997 "Determination of Air Permeability of Textile Fabrics", the samples were flatly clamped on the testing device, and a pressure difference of 100 Pa was used as the test condition. The device was started and the air permeability was recorded within 1 minute. Each sample was measured 3 times and the average value was taken to obtain the initial air permeability.

[0097] The cleaning process was then simulated by immersing the samples in a 0.5% neutral detergent solution (type 4A neutral detergent as specified in ISO 6330 standard) and washing them at 30°C with a stirring rate of 200 rpm for 10 minutes. The samples were then rinsed with deionized water until no foam residue remained, and then dried at 60°C for 30 minutes. After cooling to room temperature, the air permeability was measured again according to the standard method and conditions described above, with each sample measured three times and the average value taken.

[0098] Assessment: Calculate the ratio of the post-wash air permeability to the initial air permeability (Recovery rate = Post-wash air permeability / Initial air permeability × 100%). A higher recovery rate indicates better air permeability recovery after the fabric layer swells after washing.

[0099] The specific data for Test Case 1 and Test Case 2 are shown in Table 4.

[0100] Table 4

[0101]

[0102] As shown in Table 4:

[0103] Regarding sweat permeability, the sweat permeability of Examples 1-3 was significantly lower than that of Comparative Examples 1-4. This indicates that the earmuffs prepared using the technical solution of this invention can effectively block sweat permeation through the synergistic effect of the fabric layer and the flexible substrate. In contrast, Comparative Example 1, which did not treat the fabric layer with the treatment liquid, had a sweat permeability as high as 28.7%. The sweat permeability of Comparative Examples 2 (without nanocellulose), 3 (without graphene oxide), and 4 (without hydrophobic treatment of the flexible substrate) also reached 15.4%, 12.9%, and 19.2%, respectively, further demonstrating the key role of the components in the treatment liquid and the hydrophobic treatment of the flexible substrate in preventing sweat permeation.

[0104] Regarding breathability recovery, Examples 1-3 also performed excellently, with Example 3 showing the highest breathability recovery rate, indicating that the fabric layer can effectively restore breathability after washing. In contrast, Comparative Examples 1-4 generally showed lower breathability recovery rates. This fully demonstrates the significant effect of the compounding of the treatment liquid components and the fabric layer treatment process in achieving the "swelling and breathability recovery after washing" function, verifying that the technical solution of this invention can effectively block sweat while ensuring the comfort of wearing the earmuffs.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An easy-to-clean industrial noise-canceling earmuff, comprising an earmuff body and an ear pad disposed on the earmuff body, wherein the ear pad comprises a flexible substrate and a fabric layer wrapped around the outer surface of the flexible substrate, characterized in that, The fabric layer is prepared as follows: the fabric is immersed in a treatment solution, cross-linked first, and then dried to obtain the fabric layer; The treatment liquid comprises the following raw materials by weight percentage: Polyacrylic acid 5%-10% Nanocellulose 3%-8% Crosslinking agent 0.3-0.7% Additives 0.1-0.5% The remainder is deionized water; The additive is graphene oxide; The crosslinking agent is glutaraldehyde.

2. The easy-to-clean industrial noise-reducing earmuff according to claim 1, characterized in that, The fabric is selected from at least one of polyester fiber fabric, nylon fabric or cotton fabric.

3. The easy-to-clean industrial noise-reducing earmuff according to claim 1, characterized in that, The bath ratio of the fabric mass to the treatment liquid volume is 1g:10-20mL.

4. The easy-to-clean industrial noise-reducing earmuff according to claim 1, characterized in that, The immersion temperature of the fabric is 20-30℃, and the immersion time of the fabric is 10-30 minutes.

5. The easy-to-clean industrial noise-reducing earmuff according to claim 1, characterized in that, The cross-linking temperature of the fabric is 40-60℃, and the cross-linking time of the fabric is 30-60 minutes.

6. The easy-to-clean industrial noise-reducing earmuff according to claim 1, characterized in that, The fabric is dried at a temperature of 60-80℃ for 10-20 minutes.

7. The easy-to-clean industrial noise-reducing earmuff according to claim 1, characterized in that, The flexible substrate is silicone or polyurethane foam, and the surface of the flexible substrate is hydrophobically treated.

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