Antibacterial silicone eartip material and its use

Abstract

The application discloses an antibacterial silica gel protective earplug material and application thereof, and belongs to the technical field of materials. The antibacterial silica gel protective earplug material comprises a copolymer of formula (I) and belongs to a silane polymer. Double bonds, fluorobenzene rings, nitrile groups, quaternary ammonium salts and other chemical structures or groups are introduced onto the silane main chain of the material, so that the earplug prepared from the material has good antibacterial property, chemical stability, flexibility, comfort, tear resistance and stain resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silica gel materials, in particular to an antibacterial silica gel protective earplug material and application thereof. BACKGROUND

[0002] As an important part of personal protective equipment, protective earplugs are widely used in industrial noise environments, swimming, sleep assistance, and special operation scenarios (such as dust prevention and foreign matter intrusion). Among them, silica gel material has become the preferred material for high-end protective earplugs due to its excellent plasticity, biocompatibility, and wearing comfort. However, the ear canal is a warm, humid, and relatively closed microenvironment, with internal temperature, humidity, and abundant organic matter (such as sebum, sweat, exfoliated epithelial cells, and earwax) providing conditions for bacterial growth, and microorganisms are prone to grow during long-term use of earplugs, leading to the risk of ear infection.

[0003] To solve this problem, the existing technology mainly realizes antibacterial function through two ways. One is surface coating technology: spraying or dipping antibacterial agents (such as silver ions, quaternary ammonium salt compounds) on the surface of silica gel earplugs to form an antibacterial layer through physical adsorption or chemical bonding. Although this method can inhibit microbial growth in the short term, it has the defects of easy wear and tear of the coating, insufficient antibacterial durability, and some antibacterial agents may cause local concentration to be too high due to too fast release rate, causing skin irritation or drug resistance problems. Two is blending modification technology: directly adding antibacterial agents into silica gel base material to realize uniform dispersion of antibacterial components through physical mixing or chemical grafting. However, traditional inorganic antibacterial agents (such as nano-zinc oxide, titanium dioxide) are prone to agglomeration in silica gel system, resulting in a decrease in mechanical properties of the material; organic antibacterial agents (such as triclosan, phenolic compounds) may release harmful substances due to poor thermal stability or high migration, which does not meet the safety standards of medical-grade materials.

[0004] In addition, the preparation process of existing antibacterial silica gel earplugs relies on multi-step method or complex equipment (such as plasma treatment, solvent volatilization molding), which has the limitations of low production efficiency, high cost, poor environmental friendliness, and is difficult to meet the needs of large-scale industrial production.

[0005] The existing technology CN118459846A discloses an antibacterial and breathable silica gel material, which includes a porous silica gel base and a composite fiber layer covering the surface of the porous silica gel base, and the fiber layer includes carbon fibers, sodium hydroxymethyl cellulose, and trehalose. Trehalose can increase the flexibility and hydrophobicity of silica gel, and has certain antibacterial properties, but it still uses a film-coated antibacterial agent, which is prone to damage and poor antibacterial performance.

[0006] The prior art CN112936730A discloses a manufacturing method of a soft and hard combined earphone earplug, TPE thermoplastic elastomer A material and TPE thermoplastic elastomer B material are respectively added into the material pipe of a double-color injection molding machine, and then the material pipe is mixed and melted to form a moldable state, and then injection molding is performed, so that the soft and hard combination is not easy to fall off, but does not have antibacterial effect.

[0007] Therefore, it is a technical problem to be solved in the art to develop a silica gel protective earplug material with high and durable antibacterial performance, excellent physical and mechanical properties and biological safety, and a simple and efficient preparation process. SUMMARY

[0008] In order to overcome the deficiencies of the prior art, the present application provides an antibacterial silica gel protective earplug material and its application.

[0009] The technical solution for achieving the purpose of the present application is as follows:

[0010] In a first aspect, the present application provides an antibacterial silica gel protective earplug material, comprising a copolymer of formula (I), the copolymer of formula (I) having the following structural formula:

[0011] Wherein the molar ratio of m, n, x, y is (5-8):(20-40):(20-30):(50-60).

[0012] The preparation method of the copolymer of formula (I) is as follows:

[0013] S1: Preparation of monomer C compound

[0014] 4-fluoro-N,N-dimethylbenzylamine and bis(3-chloropropyl) dichlorosilane are dissolved in xylene solvent, heated and refluxed under nitrogen atmosphere, the reaction is stopped, and monomer C is obtained by purification, and the monomer C has the structure of formula (II).

[0015]

[0016] S2: Copolymerization of monomer A (diallyl dichlorosilane), monomer B (pentafluorophenylpropylmethyl dichlorosilane), monomer C, and monomer D ((3-cyanopropyl) phenyl dichlorosilane) to prepare the copolymer of formula (I).

[0017] In a nitrogen atmosphere, the monomers A, B, C, and D are dissolved in a mixed solvent of toluene and cyclohexane, stirred in an ice water bath, and slowly added dropwise with sodium hydroxide solution until the pH is neutral. Continue stirring until the reaction is complete, let it stand and separate the layers, remove the water phase, and retain the organic phase. After washing with saturated sodium bicarbonate, retain the organic phase and dry it with anhydrous magnesium sulfate. Add tetramethylammonium hydroxide (dehydrating agent) to the dried organic phase, heat and stir at 60°C under nitrogen protection, and distill under reduced pressure for 2-5 hours. Vacuum drying obtains the copolymer of formula (I).

[0018] The molar ratio of 4-fluoro-N, N-dimethylbenzylamine to bis(3-chloropropyl) dichlorosilane in step S1 is 1:(1-1.3), preferably 1:1.2.

[0019] The molar ratio of monomers A, B, C, and D in step S2 is (5-8):(20-40):(20-30):(50-60), preferably (6-7):(35-40):(25-30):(55-60).

[0020] The amount of tetramethylammonium hydroxide added in step S2 is 100-200 ppm, preferably 150 ppm.

[0021] In a second aspect, the application provides the use of an antibacterial silicone protective earplug material for preparing earplugs, wherein the material comprises a copolymer of formula (I).

[0022] In a third aspect, the application provides an antibacterial silicone protective earplug material, which comprises 100 parts of a copolymer of formula (I), and at least one of 0.5-5 parts of a crosslinking agent, 0.1-2 parts of a foaming agent, 0.01-0.05 parts of a foam stabilizer, 0.005-0.05 parts of a catalyst, and 0.1-2 parts of a colorant.

[0023] The crosslinking agent is selected from at least one of triethanolamine, diethanolamine, dimethylsilane, and hydrogen-containing silicone oil.

[0024] The foam stabilizer is selected from at least one of AC-5359H and L580.

[0025] The catalyst is selected from at least one of organic peroxide and metal catalyst.

[0026] Advantages

[0027] The application provides an antibacterial silicone protective earplug material and its application, wherein the antibacterial silicone protective earplug material comprises a copolymer of formula (I), and the earplug prepared from the material has good antibacterial properties, chemical stability, flexibility, comfort, tear resistance, and stain resistance, and has the following advantages:

[0028] (1)Antibacterial property: the quaternary ammonium salt structure of the formula (I) copolymer has antibacterial property, which is not possessed by the commonly used earplug preparation material such as silicone material PDMS (polydimethylsiloxane) and the like. The antibacterial compound (monomer C) prepared by using 4-fluoro-N, N-dimethylbenzylamine and bis (3-chloropropyl) dichlorosilane in the present application has similar chemical structure to the commercially available broad-spectrum antibacterial agent benzalkonium chloride, but the monomer C has stronger and broader antibacterial effect than benzalkonium chloride due to the introduction of fluorine F atom on the benzene ring and the change of chlorosilane structure, which changes the molecular polarity. Moreover, the monomer C can be uniformly distributed in the formula (I) copolymer through polymerization reaction, which is used for preparing earplugs, and there is no need to physically dope and coat antibacterial agent on the surface, thereby avoiding the problems of uneven distribution of antibacterial agent and easy peeling of antibacterial coating, reducing the process of preparing earplugs, and being beneficial to reducing the risk of ear canal infection, improving the safety of use and reducing the production cost.

[0029] (2) Chemical stability and stain resistance: the ear canal of human body is easy to have oil stains, sweat stains, exfoliated skin and ear canal secretions, which are attached to the surface of earplugs. The fluorinated benzene ring structure in the formula (I) copolymer makes the polymer have similar properties to Teflon, which endows it with excellent ultraviolet resistance, chemical corrosion resistance and low surface energy anti-adhesion. In addition, the introduction of nitrile group in the formula (I) polymer can further enhance the oil stain resistance. The above groups can effectively prevent the pollution or chemical corrosion of earplugs by oil stains, sweat stains and the like in the ear canal.

[0030] (3) Flexible, comfortable and tear-resistant: although the commercially available PDMS itself also has good flexibility, the combination of siloxane segment, fluorinated benzene ring and quaternary ammonium salt structure in the formula (I) copolymer can bring more excellent flexibility and elastic recovery capacity, which is due to the multi-benzene ring structure and fatty chain structure contained in the side chain of the polymer. The earplugs prepared from the copolymer can adapt to different ear canal shapes and maintain wearing comfort. The double bond introduced in the formula (I) copolymer can better form crosslinking by adding initiator during the preparation of earplugs, thereby improving the tear resistance of earplugs and improving the product quality. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is the synthesis route diagram of the formula (I) copolymer.

[0032] Figure 2 is the infrared spectrum diagram of the formula (I) copolymer. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0034] The raw materials used in the examples and comparative examples are described as follows.

[0035] Diallyldichlorosilane: purchased from Shanghai Taogui New Material Technology Co., Ltd.

[0036] Pentafluorophenylpropylmethyldichlorosilane: purchased from Shanghai Taogui New Material Technology Co., Ltd.

[0037] Bis(3-chloropropyl)dichlorosilane: purchased from Shanghai Shiyan Chemical Co., Ltd.

[0038] (3-Cyanopropyl)phenyldichlorosilane: purchased from Xuzhou Zhuoyun New Material Technology Co., Ltd.

[0039] 4-Fluoro-N,N-dimethylbenzylamine: purchased from Zhengzhou Weiyi Chemical Product Co., Ltd.

[0040] Unless otherwise specified, the component raw materials used in the embodiments and comparative examples of the present application are commercially available raw materials, and the component raw materials used in each parallel experiment or comparative experiment are the same, and the experimental methods used are all carried out under the same conditions.

[0041] Example 1

[0042] An antibacterial silicone earplug material includes a copolymer of formula (I), and the specific preparation method is as follows:

[0043] S1: Preparation of monomer C compound

[0044] 4-Fluoro-N,N-dimethylbenzylamine and bis(3-chloropropyl)dichlorosilane were dissolved in a xylene solvent, heated to reflux under a nitrogen atmosphere for 3 h, and then the reaction was stopped to prepare a liquid phase purification monomer C. The molar ratio of 4-fluoro-N,N-dimethylbenzylamine to bis(3-chloropropyl)dichlorosilane was 1:1.2.

[0045] S2: Copolymerization of monomers A, B, C and D to prepare a copolymer of formula (I)

[0046] The monomers A, B, C and D are dissolved in a mixture of toluene and cyclohexane under a nitrogen atmosphere. A 1 mol / L sodium hydroxide solution is slowly added dropwise under stirring in an ice water bath until the pH is neutral. The stirring is continued for 2 hours until the reaction is completed. The mixture is allowed to stand and separate into layers. The water phase is removed and the organic phase is retained. The organic phase is washed with saturated sodium bicarbonate and then dried with anhydrous magnesium sulfate. Tetramethylammonium hydroxide (dehydrating agent) is added to the dried organic phase. The mixture is heated and stirred at 60°C under nitrogen protection. The mixture is distilled under reduced pressure for 4 hours. The copolymer of formula (I) is obtained by vacuum drying.

[0047] The molar ratio of the monomers A, B, C and D used in step S2 is 6:35:25:56.

[0048] The amount of tetramethylammonium hydroxide added in step S2 is 150 ppm.

[0049] The infrared spectrum of the copolymer of formula (I) is shown in the attached Figure 2 , 2800-2950 cm -1 is the stretching vibration peak of -CH3 of the quaternary ammonium group, 3080 cm -1 is the corresponding absorption peak of =C-H stretching vibration, 2240 cm -1 is the stretching vibration of C≡N in the cyano group, 1200 cm -1 is the stretching vibration peak of C-F in the fluorophenyl group, 1046 cm -1 is the stretching vibration peak of Si-O-Si.

[0050] Example 2

[0051] An antibacterial silicone earplug material comprising the copolymer of formula (I), the difference between the specific preparation method and Example 1 is only that the molar ratio of the monomers A, B, C and D is adjusted to be preferably 7:30:20:60.

[0052] Example 3

[0053] An antibacterial silicone earplug material comprising the copolymer of formula (I), the difference between the specific preparation method and Example 1 is only that the molar ratio of the monomers A, B, C and D is adjusted to be preferably 8:20:30:50.

[0054] Comparative Examples 1-5

[0055] An earplug material is prepared, the difference between the specific preparation method and Example 1 is only that the type and amount of monomers are adjusted.

[0056] Table 1: Ingredient table of Examples 1-3 and Comparative Examples 1-5

[0057]

[0058]

[0059] Application Examples 1-3, Comparative Application Examples 1-5

[0060] The copolymer of formula (I) prepared in Example 1-3, Comparative Example 1-5 was used for the preparation of Application Examples 1-3, Comparative Application Examples 1-5, respectively. The specific preparation method: the copolymer of formula (I) was added to a high-speed mixer, the stirring speed was set to 600 r / min for 5 min, 200 ppm of BIBP was added, the stirring speed was set to 1600 r / min for 5 min. The obtained mixture was added to a twin-screw extruder, wherein the temperature of each zone of the extruder barrel was 140, 150, 150, 150, 150, 150, 150, 140 °C (die temperature), the main machine speed was 400 r / min, the feeding speed was 30 r / min, and the vulcanized and crosslinked copolymer of formula (I) was obtained by extrusion. According to different performance test requirements, the corresponding test samples were prepared.

[0061] (1) Antibacterial test

[0062] Antibacterial performance test: tested according to the method of GB / T31402-2023 (Determination of antibacterial activity on the surface of plastics and other non-porous materials), and the bacteria selected were Staphylococcus aureus (ATCC6538), Escherichia coli (ATCC8739), and Pseudomonas aeruginosa (ATCC27853).

[0063] Test method: the vulcanized and crosslinked copolymer of formula (I) of Application Examples 1-3, Comparative Application Examples 1-5 was prepared into flat sheet (50 mm x 50 mm x 3 mm) for testing, 3 test samples of each experimental group were inoculated with different bacteria, and a blank group with sterile distilled water instead of bacteria was set. The test sample of Comparative Application Example 5 was used as a negative control group.

[0064] Preparation of bacterial solution: the bacteria were inoculated into nutrient broth (NB) and cultured at 37 °C for 24 h. The bacterial solution was centrifuged (3000 rpm, 10 min), resuspended with PBS buffer, and the concentration was adjusted to 2.5 x 10 5 ~ 1.0 x 10 6 CFU / mL, and calibrated by plate counting method.

[0065] Bacterial inoculation and contact culture: 100 μL of bacterial solution was added to the surface of the test sample. A sterile PE film (40 x 40 mm) was covered, and the bubbles were removed by light pressing to ensure uniform contact of the bacterial solution with the sample surface. The sample was placed in a sterile culture dish (containing a wet filter paper to maintain humidity). Incubate at 37 °C, relative humidity > 90% for 24 h.

[0066] Elution and counting: the sample was taken out, put into 10 mL PBS buffer (containing 0.1% Tween 80), vortexed for 1 min, and the eluate was diluted by 10-fold gradient, inoculated into nutrient light plates, and cultured at 37°C for 24-48 h, and the viable colony number (CFU) was counted.

[0067] Result recording and calculation:

[0068] M0: average bacterial concentration (CFU / mL) of the blank control (0 h);

[0069] M t : average bacterial concentration (CFU / mL) of the antibacterial sample after 24 h of contact;

[0070] C t : average bacterial concentration (CFU / mL) of the negative control sample after 24 h of contact;

[0071] C0: initial bacterial concentration (CFU / mL) of the negative control;

[0072] Antibacterial rate = (C t -M t ) / C t × 100%.

[0073] Table 2: antibacterial rate table

[0074]

[0075]

[0076] As can be seen from the above table, the antibacterial rates of application examples 1-3 against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa are 98.33-99.95%, 98.42-99.97% and 97.63-99.48% respectively, which shows that the (I) copolymer prepared in examples 1-3 has excellent antibacterial performance. Because the test samples in comparative application examples 3 and 5 do not contain the quaternary ammonium salt antibacterial component (monomer C), they do not have significant antibacterial effect, but the antibacterial rates of comparative application examples 3 and 5 are not zero, which may be related to the performance of the silica gel material itself and experimental errors. The test samples in comparative application examples 1, 2 and 4 also contain the quaternary ammonium salt antibacterial component (monomer C), and also show excellent antibacterial performance. As can be seen from the comparison of application examples 1-3, comparative application examples 2 and 4, and comparative application examples 3 and 5, the quaternary ammonium salt antibacterial component (monomer C) in the present application can effectively enhance the antibacterial performance of the silica gel material. At the same time, it is known from the prior art that benzalkonium chloride is ineffective against Pseudomonas aeruginosa, and therefore the quaternary ammonium salt antibacterial component (monomer C) contained in the test samples prepared in application examples 1-3 has a wider antibacterial range than benzalkonium chloride.

[0077] (2) Tensile property and hardness test

[0078] The elongation at break was determined according to GB / T 1040.1-2018 "Determination of tensile properties of plastics".

[0079] The Shore A hardness was determined according to GB / T 531-2008 "Shore A hardness test method for vulcanized rubber".

[0080] The contact angle was determined according to GB / T 30693-2014 "Determination of oil resistance on the surface of plastics".

[0081] Table 3 Tensile, hardness, and oil resistance determination data

[0082]

[0083] According to the data in the above table, the elongation at break of application examples 1-3 is significantly improved compared to comparative application example 1-5, but the tensile strength of application examples 1-3 is significantly changed compared to application examples 1 and 5, which indicates that the tensile strength is related to the double bond of monomer A (diallyldichlorosilane), and the double bond can strengthen the crosslinking of copolymer (I) under the action of vulcanizing agent, thereby improving the tensile strength. The molar ratio of the amount of different monomers A, B, C, and D can affect the crosslinking elongation at break of copolymer (I) after vulcanization and crosslinking, can improve the tear resistance of the prepared earplugs, and improve the product quality. According to the hardness of application examples 1-3, introducing branched chains (monomers A, B, C, and D) on the polysilane main chain can reduce the hardness of copolymer (I) after vulcanization and crosslinking, enhance the flexibility, and improve the comfort of wearing the prepared earplugs. According to the contact angle of the prepared test sample and n-hexane in application examples 1-3, the prepared test sample in application examples 1-3 has significant oil repellency, which is related to the introduction of polar groups of nitrile groups on the silane main chain.

[0084] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details, nor limit the application to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of the present application. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well understand and utilize the present application. The present application is limited only by the claims and their full scope and equivalents.

Claims

1. An antibacterial silicone protective earplug material, characterized in that, Including copolymers of formula (I), which have the following structural formula: The molar ratio of m, n, x, y is (5-8):(20-40):(20-30):(50-60).

2. The antibacterial silicone protective earplug material according to claim 1, characterized in that, The preparation method of the copolymer of formula (I) is as follows: S1: Preparation of monomeric C compounds: 4-Fluoro-N,N-dimethylbenzylamine and bis(3-chloropropyl)dichlorosilane were dissolved in xylene solvent, and the reaction was stopped by heating under nitrogen atmosphere and reflux. The monomer C was purified to obtain monomer C, which has the structure of formula (II). S2: The copolymer of monomer A diallyl dichlorosilane, monomer B pentafluorophenylpropylmethyl dichlorosilane, monomer C, and monomer D (3-cyanopropyl)phenyl dichlorosilane is prepared by copolymerization of (I) monomer.

3. The antibacterial silicone protective earplug material according to claim 2, characterized in that, The specific steps of step S2 are as follows: Under a nitrogen atmosphere, monomers A, B, C, and D were dissolved in a mixed solvent of toluene and cyclohexane. The mixture was placed in an ice-water bath with stirring, and sodium hydroxide solution was slowly added dropwise until the pH was neutral. The mixture was stirred until the reaction was complete, and the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was retained. The organic phase was washed with saturated sodium bicarbonate and then dried with anhydrous magnesium sulfate. Tetramethylammonium hydroxide was added to the dried organic phase, and the mixture was heated and stirred under nitrogen protection. The mixture was then distilled under reduced pressure for 2-5 hours and dried under vacuum to obtain copolymer (I).

4. The antibacterial silicone protective earplug material according to claim 2, characterized in that, The molar ratio of 4-fluoro-N,N-dimethylbenzylamine to bis(3-chloropropyl)dichlorosilane in step S1 is 1:(1-1.3).

5. The antibacterial silicone protective earplug material according to claim 2, characterized in that: The molar ratio of monomers A, B, C, and D used in step S2 is (5-8):(30-40):(20-30):(50-60).

6. The antibacterial silicone protective earplug material according to claim 1, characterized in that: The product, by weight equivalent to the copolymer of formula (I), further includes at least one of the following: 0.5–5 wt% crosslinking agent, 0.1–2 wt% foaming agent, 0.01–0.05 wt% foam stabilizer, 0.005–0.05 wt% catalyst, and 0.1–2 wt% colorant.

7. The antibacterial silicone protective earplug material according to claim 6, characterized in that: The crosslinking agent is selected from at least one of triethanolamine, diethanolamine, dimethylsilane, and hydrogen-containing silicone oil.

8. The antibacterial silicone protective earplug material according to claim 6, characterized in that: The catalyst is selected from at least one of organic peroxides and metal catalysts.

9. The application of the antibacterial silicone protective earplug material according to any one of claims 1-8 in the manufacture of earplugs.

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