Toothbrush filament and its manufacturing method, toothbrush

Abstract

A method for manufacturing a toothbrush filament, and the manufactured toothbrush filament and toothbrush, which includes melt extrusion of a piezoelectric polymer and undergoes corona polarization and annealing processes, thereby making the piezoelectric constant of the toothbrush filament in a stationary state 0.4 pC / N or more, and having a certain stably present polarization charge on its surface, and utilizing the antibacterial action mechanism based on physical electrical stimulation, can effectively improve the problem of mass bacterial proliferation on the toothbrush filament in a stationary state, thereby improving the antibacterial performance of the toothbrush filament.

Description

[Technical Field]

[0001] This application claims priority to a Chinese patent application filed with the China Patent Office on May 9, 2022, bearing application number 202210502051.9, entitled "Toothbrush filament and manufacturing method thereof, toothbrush," and a Chinese patent application filed with the China Patent Office on June 10, 2022, bearing application number 202210655802.0, entitled "Toothbrush filament and manufacturing method thereof, toothbrush," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to the technical field of oral hygiene, and in particular to toothbrush filaments and methods of making same, and toothbrushes. [Background technology]

[0003] Toothbrushes are everyday items whose function is to maintain oral hygiene by cleaning the teeth and gums and removing debris from the mouth. Traditional toothbrush filaments are generally made of natural boar bristles or nylon materials.

[0004] Although natural boar bristles have superior cleaning properties and toothpaste adsorption capabilities to nylon materials, their limited availability limits their scope of use. Nylon materials, on the other hand, have relatively good toughness but lack antibacterial properties. During use, toothbrush filaments come into contact with water or food residue. Because toothbrush filaments are relatively dense, food residue remains on the filaments, making them difficult to thoroughly remove. Over time, bacteria grow on the filaments, making them susceptible to oral infections and adversely affecting overall health. Furthermore, traditional toothbrushes only function to clean food residue from the oral cavity, lack antibacterial properties, and fail to inhibit or remove bacteria on the tooth surface, adversely affecting the prevention of certain oral diseases, such as dental caries and periodontal disease. Therefore, improving the antibacterial properties of toothbrush filaments is an urgent problem. Summary of the Invention

[0005] The present application aims to provide a toothbrush filament, a manufacturing method thereof, and a toothbrush, which can improve the antibacterial properties of the toothbrush filament. Specific embodiments are as follows:

[0006] In a first aspect of the present application, there is provided a method for manufacturing a toothbrush filament, comprising the steps of: (1) A piezoelectric polymer is added to a melt spinning machine, heated to the melting temperature of the piezoelectric polymer, and extruded to obtain threads with a diameter of 100 μm to 500 μm, and the piezoelectric constant of the piezoelectric polymer is 10 pC / N to 32 pC / N. (2) The thread is annealed at 120°C to 150°C for 1.5 to 3 hours, and then the annealed thread is subjected to corona polarization to obtain a toothbrush filament, where the corona polarization voltage is 10 kV to 50 kV, the distance between the electrode and the sample is 10 mm to 50 mm, the polarization temperature is 25°C to 50°C, and the time is 10 min to 60 min, and preferably the annealing temperature is 120°C to 140°C, the time is 2 h to 3 h, the corona polarization voltage is 20 kV to 50 kV, the distance is 20 mm to 50 mm, the temperature is 25°C to 50°C, and the time is 10 min to 40 min. Alternatively, (2') After corona polarization treatment of the yarn, the thread is annealed at 120°C to 150°C for 1.5 hours to 3 hours to obtain a toothbrush filament. The corona polarization treatment is performed at a voltage of 10kV to 50kV, a distance of 10mm to 50mm, a temperature of 25°C to 50°C, and a time of 10min to 60min, and preferably at a voltage of 20kV to 50kV, a distance of 20mm to 50mm, a temperature of 25°C to 50°C, and a time of 10min to 40min, and at an annealing temperature of 120°C to 140°C, and a time of 2h to 3h.

[0007] In some embodiments of the present application, the piezoelectric polymer is at least one selected from polyvinylidene fluoride, polyvinylidene fluoride-trifluoroethylene copolymer, or polyvinylidene fluoride-hexafluoropropylene copolymer.

[0008] In a second aspect, the present application provides a toothbrush filament manufactured using the manufacturing method of any of the above-described embodiments.

[0009] In some embodiments of the present application, the voltage generated by the filament of the toothbrush when subjected to an external force is 0.6V to 1.5V.

[0010] In some embodiments of the present application, the toothbrush filament has a monofilament bend recovery of 60% to 80%.

[0011] In some embodiments of the present application, the toothbrush filaments have a piezoelectric constant of 0.4 pC / N or greater in a rest state.

[0012] In some embodiments of the present application, the toothbrush filaments have an antibacterial rate of 45% to 80%.

[0013] In a third aspect of the present application, there is provided a toothbrush, including a traditional manual toothbrush or an electric toothbrush, comprising a filament of any of the toothbrush embodiments described above.

[0014] The advantageous effects of the present invention are as follows: This application provides a toothbrush filament, a manufacturing method thereof, and a toothbrush. The toothbrush filament is manufactured using this manufacturing method, and the temperature and time of the annealing treatment are controlled, and the voltage, distance, temperature, and time of the corona polarization treatment are controlled within the above-mentioned ranges. The toothbrush filament thus manufactured has good piezoelectric properties and monofilament bending recovery. Specifically, the toothbrush filament has a piezoelectric constant of 0.4 pC / N or more in a static state and a stable polarization charge on its surface. The antibacterial mechanism of action is based on physical electrical stimulation, effectively alleviating the problem of bacterial proliferation on toothbrush filaments in a static state, thereby improving the antibacterial performance of the toothbrush filament. The toothbrush filament generates a voltage of 0.6 V to 1.5 V when subjected to external force (corresponding to the toothbrush process). Therefore, the piezoelectric signal from the toothbrush filament during the cleaning process can effectively remove bacteria from the tooth surface, contributing to the prevention of dental diseases such as caries and periodontal disease. In addition, the monofilament bending recovery rate of the toothbrush filament is 60% to 80%, which satisfies the requirements for use of the toothbrush. Of course, it is not necessary for all of the above advantages to be realized simultaneously in practicing any product or method herein.

[0015] In order to more clearly explain the configuration of the embodiments of the present invention and the prior art, the drawings necessary for use in the embodiments and the prior art will be briefly described below. However, it is clear that the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings from these drawings without any inventive or creative efforts. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a dynamic piezoelectric signal test chart of the toothbrushes of Examples 1, 2, 12, 13, Comparative Example 1, and Comparative Example 2 when an external force is applied to the filaments. [Figure 2] 1 is a graph showing test results of the static piezoelectric constant d33 of the filaments of the toothbrushes of Examples 1, 2, 12, 13, and Comparative Examples 1 and 2. [Figure 3] 1 is a test chart showing the antibacterial performance of the filaments of the toothbrushes of Examples 1, 2, 12, 13, and Comparative Examples 1 and 2. [Figure 4] Figure 4a (400x magnification) and Figure 4b (5000x magnification) are electron microscope photographs of the filaments of the toothbrush of Example 1 after 24 hours of co-cultivation with bacteria. [Figure 5] Figure 5a (400x magnification) and Figure 5b (5000x magnification) are electron microscope photographs of the toothbrush filaments of Example 2 after 24 hours of co-cultivation with bacteria. [Figure 6] Figure 6a (400x magnification) and Figure 6b (5000x magnification) are electron micrographs of the toothbrush filaments of Example 12 after 24 hours of co-cultivation with bacteria. [Figure 7] Figure 7a (400x magnification) and Figure 7b (5000x magnification) are electron micrographs of the toothbrush filaments of Example 13 after 24 hours of co-cultivation with bacteria. [Figure 8] FIG. 8a (400x magnification) and FIG. 8b (5000x magnification) are electron microscope photographs of the filaments of the toothbrush of Comparative Example 1 after 24 hours of co-cultivation with bacteria. [Figure 9] FIG. 9a (400x magnification) and FIG. 9b (5000x magnification) are electron microscope photographs of the filaments of the toothbrush of Comparative Example 2 after 24 hours of co-cultivation with bacteria. [Figure 10] 1 shows X-ray diffraction spectra of the filaments of the toothbrushes of Examples 1, 2, 12, 13, and Comparative Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0017] In order to make the objects, embodiments, and advantages of the present invention clearer, the present invention will be described in more detail below with reference to the drawings and examples. Obviously, the described examples are only some of the examples of the present invention, and are not all of the examples. Any other examples made by those skilled in the art based on the examples of the present invention without any inventive ideas are all included in the scope of the present invention.

[0018] In a first aspect of the present application, there is provided a method for manufacturing a toothbrush filament, comprising the steps of: (1) A piezoelectric polymer is added to a melt spinning machine, heated to the melting temperature of the piezoelectric polymer, and extruded to obtain threads with a diameter of 100 μm to 500 μm, and the piezoelectric constant of the piezoelectric polymer is 10 pC / N to 32 pC / N. (2) The thread is annealed at 120°C to 150°C for 1.5 to 3 hours, and then the annealed thread is subjected to corona polarization to obtain a toothbrush filament. The corona polarization is performed at a voltage of 10 kV to 50 kV, a distance between the electrode and the sample of 10 mm to 50 mm, a polarization temperature of 25°C to 50°C, and a time of 10 to 60 minutes. Preferably, the annealing temperature is 120°C to 140°C, the time is 2 to 3 hours, the corona polarization voltage is 20 kV to 50 kV, the distance is 20 mm to 50 mm, the temperature is 25°C to 50°C, and the time is 10 to 40 minutes. For example, the annealing temperature may be 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, or a range between any two of these values, and the annealing time may be 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 3 hours, or a range between any two of these values. For example, the voltage of the corona polarization treatment may be 10 KV, 20 KV, 30 KV, 40 KV, 50 KV, or a range between any two of these values; the distance of the corona polarization treatment may be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, or a range between any two of these values; the temperature of the corona polarization treatment may be 25° C., 30° C., 35° C., 40° C., 45° C., 50° C., or a range between any two of these values; and the time of the corona polarization treatment may be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, or a range between any two of these values. (2') After corona polarization treatment of the yarn, the thread is annealed at 120°C to 150°C for 1.5 hours to 3 hours to obtain a toothbrush filament. The corona polarization treatment is performed at a voltage of 10kV to 50kV, a distance of 10mm to 50mm, a temperature of 25°C to 50°C, and a time of 10min to 60min, and preferably at a voltage of 20kV to 50kV, a distance of 20mm to 50mm, a temperature of 25°C to 50°C, and a time of 10min to 40min, and at an annealing temperature of 120°C to 140°C, and a time of 2h to 3h. For example, the voltage of the corona polarization treatment may be 10 KV, 20 KV, 30 KV, 40 KV, 50 KV, or a range between any two of these values; the distance of the corona polarization treatment may be 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, or a range between any two of these values; the temperature of the corona polarization treatment may be 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, or a range between any two of these values; and the time of the corona polarization treatment may be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, or a range between any two of these values. For example, the annealing temperature may be 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, or a range between any two of these values, and the annealing time may be 1.5 hours, 1.8 hours, 2 hours, 2.2 hours, 2.5 hours, 3 hours, or a range between any two of these values.

[0019] The annealing treatment improves the degree of polymer crystallinity, thereby improving the plasticity and toughness of the toothbrush filaments and eliminating residual stress. If the annealing temperature is too low (e.g., below 120°C) or the time is too short (e.g., less than 1.5 hours), the annealing will be incomplete, affecting the physical properties of the toothbrush filaments, such as the monofilament's bending recovery rate. If the annealing temperature is too high (e.g., above 150°C) or the time is too long (e.g., more than 3 hours), not only will it affect practical feasibility, but it will also affect the mechanical properties of the toothbrush filaments themselves.

[0020] The corona polarization treatment can impart a certain polarization charge to the surface of the toothbrush filament, improving the piezoelectric performance of the toothbrush filament. If the corona polarization treatment voltage is too low (e.g., less than 10 KV), the distance is too long (e.g., more than 50 mm), the temperature is too low (e.g., less than 25°C), or the time is too short (e.g., less than 10 minutes), the corona polarization treatment will be incomplete, which will directly affect the improvement of the piezoelectric performance of the toothbrush filament. If the corona polarization treatment voltage is too high (e.g., less than 50 KV), super )), the distance is too small (e.g., more than 10 mm less than This appears to be a typo.)) If the temperature is too high (e.g., above 50°C) or the time is too long (e.g., above 60 minutes), not only will safety risks increase during use, but the mechanical properties of the toothbrush filaments will also be affected.

[0021] Generally, toothbrush filaments manufactured using the above manufacturing method, either by annealing the yarn before corona poling or by corona poling the yarn before annealing, and controlling the annealing temperature and time, and controlling the corona poling voltage, distance, temperature, and time within the above ranges, have good piezoelectric properties and monofilament bending recovery. Specifically, the toothbrush filaments have a piezoelectric constant of 0.4 pC / N or more in a static state and a stable polarization charge on their surfaces. The antibacterial mechanism of action is physical electrical stimulation, which effectively alleviates the problem of bacterial proliferation on toothbrush filaments in a static state, thereby improving the antibacterial performance of the toothbrush filaments. The toothbrush filaments generate a voltage of 0.6 V to 1.5 V when subjected to external force (corresponding to the toothbrush process), and the piezoelectric signal from the toothbrush filaments during the cleaning process effectively removes bacteria from the tooth surface, which is beneficial for preventing dental diseases such as caries and periodontal disease. Under the condition that the lowest annealing temperature and time are satisfied, the monofilament bending recovery rate of the toothbrush filament is 60% to 80%, which is in accordance with the Chinese national standard GB 19342-2013 ("Toothbrush") and satisfies the requirements for toothbrush use. The external force is an ultrasonic vibration of 40,000 times per minute. The toothbrush filament's piezoelectric constant in a resting state is 0.4 pC / N or more, which is smaller than the piezoelectric constant of the piezoelectric polymer used to make the toothbrush filament.

[0022] In some embodiments of the present application, the piezoelectric polymer is at least one selected from polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-hexafluoropropylene copolymer. The piezoelectric constants of polyvinylidene fluoride (PVDF), polyvinylidene fluoride-trifluoroethylene copolymer, and polyvinylidene fluoride-hexafluoropropylene copolymer are 18 pC / N to 22 pC / N, 25 pC / N to 29 pC / N, and 27 pC / N to 30 pC / N, respectively. PVDF is a polycrystalline semi-crystalline polymer with three commonly observed crystalline forms: α-phase, β-phase, and γ-phase. The β-phase is a ferroelectric phase, and its proportion directly determines the polarization charging effect and piezoelectric performance of PVDF. The post-treatment process directly affects the crystalline phase of PVDF. In this application, the post-treatment process combines annealing and corona polarization to significantly increase the proportion of β phase in PVDF, improving the piezoelectric performance of the toothbrush filaments produced, thereby realizing the antibacterial function of the toothbrush filaments.

[0023] In the present application, there is no particular limitation on the melting temperature of the piezoelectric polymer as long as the object of the present application can be achieved, and for example, the melting temperature of the piezoelectric polymer may be 130°C to 220°C. Furthermore, the melting temperatures of the above-mentioned PVDF, polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE), and polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP) are 165°C to 175°C, 212°C to 217°C, and 130.9°C to 180°C, respectively. In the present application, there is no particular limitation on the molecular weight of the piezoelectric polymer as long as the object of the present application can be achieved, and for example, the weight-average molecular weights of the above-mentioned PVDF, polyvinylidene fluoride-trifluoroethylene, and polyvinylidene fluoride-hexafluoropropylene are 150,000 to 300,000, 100,000 to 200,000, and 700,000 to 900,000, respectively.

[0024] In the present application, there is no particular limitation on the melt spinning machine used in the above-mentioned production method, and any melt spinning machine known in the art can be used as long as the object of the present application can be achieved. A second aspect of the present application provides a toothbrush filament manufactured using the manufacturing method of any of the above-described embodiments. The toothbrush filament manufactured using the above manufacturing method has good piezoelectric performance and monofilament bending recovery rate, specifically, the toothbrush filament has a piezoelectric constant of 0.4 pC / N or more in a stationary state, a voltage signal generated by the toothbrush filament in response to an external force of 0.6 V to 1.5 V, and a monofilament bending recovery rate of 60% to 80%.

[0025] In some embodiments of the present application, the antibacterial rate of the toothbrush filaments is 45% to 80%, indicating good antibacterial performance.

[0026] In a third aspect of the present application, there is provided a toothbrush including a toothbrush filament according to any of the above-described embodiments. Because the toothbrush filament has good piezoelectric properties and a monofilament bending recovery rate, the toothbrush according to the present application has good antibacterial properties and usability. The piezoelectric response of the toothbrush filament during cleaning can also effectively remove bacteria from the tooth surface, contributing to the improvement of dental diseases such as tooth spot bacteria and periodontal disease.

[0027] Measurement methods and equipment: Dynamic Piezoelectric Performance Measurement: The filament was cut to a length of 10 cm and clamped to make the filament taut. Conductive adhesive and electrodes were attached to both ends, and the electrodes connected to both ends were connected to a Keithley electrometer (Keithley 6514). Ultrasonic vibrations at a frequency of 40,000 times per minute were applied, causing the filament movement device to fluctuate regularly, and the voltage output was received on a screen.

[0028] Static Piezoelectric Performance Measurement: For the filaments of the toothbrushes of the different examples and comparative examples, the quasi-static d 33 The piezoelectric constant d of the toothbrush filament was measured using a measuring instrument (ZJ-6A, Institute of Acoustics, Chinese Academy of Sciences). 33The edge of the toothbrush filament material was lightly pinched with small tweezers and placed between the measurement electrodes at both ends of the quasi-static measuring device, and the upper button was gently rotated to lightly bring the two electrodes into contact, and the data displayed on the screen was recorded. Measurements were taken at five points for each filament, and the average value was used as the final measurement result.

[0029] Tensile strength and modulus measurements: Before applying the load, the initial distance between the clamps of the tensile testing table (Instron-1121, Cambridge) was adjusted to 100 mm ± 5 mm. The toothbrush filament was immersed in deionized water for 1 minute, then clamped between the two clamps. A load was applied at a crosshead speed of (300 ± 50) mm / min. The strain-load relationship was recorded until the filament broke, and the tensile strength and modulus were measured.

[0030] Measurement of hair bundle tension, hair bundle bending force, and monofilament bending recovery rate: The tuft tension, tuft bending force, and monofilament bending recovery were all measured according to Chinese national standard GB 19342-2013.

[0031] Antibacterial performance measurement: (1) Preparation of brain heart infusion medium (BHI liquid medium): 7.4 g of BHI powder (200 g bovine brain, 250 g bovine heart infusion, 10 g peptone, 2 g glucose, 5 g NaCl, 20 g agar) was weighed, 400 ml deionized water was added, and the mixture was mixed uniformly. The mixture was then heated at 120°C under high pressure for use. Preparation of solid medium: 2% agar powder was added to the dissolved liquid medium, sterilized under high pressure, and cooled to 70°C. The mixture was poured into a 9 cm culture dish in a clean bench. After cooling, the dish was inverted, sealed, and stored in a refrigerator at 4°C. (2) The experimental strain was selected as the mutans Streptococcus ua159, a bacterium that causes dental caries. The experimental strain was revived and inoculated onto solid medium. It was then cultured for 24 hours in a 37°C, 5% CO2 incubator. Some colonies were collected and Gram-stained, and the morphology of the colonies was observed under an optical microscope. After confirming that there was no contamination, some were subcultured for use. (3) The filaments of the toothbrushes of each example and comparative example were disinfected with absolute ethanol and then co-cultured with Streptococcus mutans in BHI liquid medium for 24 hours. (4) Preparation of staining solution: The fluorescent staining agent contains two types of dyes, SYT09 dye and PI dye, which can cause live bacteria to emit green fluorescence and dead bacteria to emit red fluorescence. Before staining, SYT09 dye and the dye reagent were mixed in equal proportions in a dark environment and placed in the same centrifuge tube (Epoxy tube), shaken to mix evenly, and then protected from light for use. (5) The toothbrush filament was co-cultured with Streptococcus mutans in BHI liquid medium for 24 hours, and the supernatant was removed with a pipette. The culture medium was then carefully and gently washed once with sterile saline to wash away the suspended bacteria. (6) An appropriate amount of staining solution was dropped onto the surface of the plaque biofilm, and the mixture was incubated at room temperature in a dark room for 15 minutes. The excess dye was removed by carefully rinsing with PBS buffer. The toothbrush filaments of each example and comparative example were placed on a glass slide and observed and photographed using a laser confocal microscope (CLSM), and the red and green fluorescence intensities were obtained. Antibacterial rate = red fluorescence intensity / (red fluorescence intensity + green fluorescence intensity) x 100%.

[0032] Measurement of absorbance (OD value) for 3 hours: The Streptococcus mutans bacteria were cultured with toothbrush filaments for 24 hours, the bacterial solution was aspirated, and the toothbrush filaments were gently washed three times with PBS buffer. Fresh BHI liquid medium was added and the culture was continued for another three hours. 100 μL of the bacterial suspension was then transferred to a 96-well plate, with five parallel wells per sample and three parallel wells per group. The OD values ​​were read at 630 nm using a microplate reader. The lower the OD value, the better the antibacterial performance of the toothbrush filaments. The OD values ​​at 0 h, 6 h, 9 h, and 12 h were measured in the same manner using the method described above.

[0033] Example 1 (1) 1 kg of PVDF was weighed and added to a single-screw melt spinning machine. The temperature was raised to the melting point of 175°C at a rate of 10°C / min. After the pellets were completely melted, they were extruded through the spinneret and wound into a 265 μm diameter yarn. The piezoelectric constant of the PVDF was 19 pC / N. (2) Then, the film was annealed at 120°C for 2 hours. (3) Then, the toothbrush filament was obtained by corona polarization treatment, and the corona polarization treatment was performed at a voltage of 35 kV, a distance of 35 mm, a temperature of 25°C, and a time of 30 min.

[0034] Examples 2 to 11 The same procedure was followed as in Example 1, except that the relevant production parameters were adjusted according to Table 1. Among these, the mass ratio of polyvinylidene fluoride to trifluoroethylene in the polyvinylidene fluoride-trifluoroethylene copolymer was 3:1, and the mass ratio of polyvinylidene fluoride to hexafluoropropylene in the polyvinylidene fluoride-hexafluoropropylene copolymer was 3:1. The piezoelectric constants of the polyvinylidene fluoride-trifluoroethylene copolymer and polyvinylidene fluoride-hexafluoropropylene copolymer were 26 pC / N and 28 pC / N, respectively. The yarn diameter could be adjusted to meet the diameters listed in Table 1 by adjusting the spinneret specifications.

[0035] Example 12 (1) 1 kg of PVDF was weighed and added to a single-screw melt spinning machine. The temperature was raised to the melting point of 175°C at a rate of 10°C / min. After the pellets were completely melted, they were extruded through the spinneret and wound into a 265 μm diameter yarn. The piezoelectric constant of the PVDF was 19 pC / N. (2) Then, the toothbrush filament was obtained by corona polarization treatment, and the corona polarization treatment was performed at a voltage of 35 kV, a distance of 35 mm, a temperature of 25°C, and a time of 30 min. (3) Then, the film was annealed at 120°C for 2 hours.

[0036] Example 13 The same as in Example 12, except that the relevant production parameters were adjusted according to Table 1.

[0037] Comparative Examples 1 to 5 The procedure was the same as in Example 1, except that the relevant production parameters were adjusted according to Table 1. Among them, the weight-average molecular weight of nylon was 15,000.

[0038] The manufacturing parameters for each example and comparative example are shown in Table 1, and the performance data are shown in Table 2. [Table 1]

[0039] [Table 2]

[0040] 1 , it is clear from Examples 1 to 13 and Comparative Examples 1 and 2 that the toothbrush filaments manufactured using the manufacturing method of the present application have good piezoelectric performance and mechanical strength, and after annealing, the bending recovery rate of the monofilament of the toothbrush filament consistently meets the Chinese national standard, exhibiting relatively good stability. Furthermore, after annealing and poling, the antibacterial performance of the toothbrush filament is enhanced, and in particular, the antibacterial performance of the toothbrush filament in the present application examples is significantly improved compared to the toothbrush filament made of a general-purpose nylon material in the prior art (Comparative Example 2). This is because the annealing and poling treatments increase the piezoelectric constant and β-phase crystallinity of PVDF, improving its electrical performance and thereby strengthening the antibacterial performance of the toothbrush filament. Specifically, as shown in FIG. 2, the filaments of the toothbrushes of Examples 1, 2, 12, and 13 had piezoelectric constants of 0.92 pC / N, 0.46 pC / N, 0.85 pC / N, and 0.45 pC / N, respectively, in a stationary state, and 3-h OD values ​​of 0.0476, 0.0500, 0.0489, and 0.0520, respectively, whereas the filaments of the toothbrushes of Comparative Examples 1 and 2 had piezoelectric constants d 33The piezoelectric constants d of the filaments of the toothbrushes of the present invention were 0.19 pC / N and 0 pC / N, respectively, and the 3h OD values ​​were 0.0673 and 0.2320, respectively. 33 1, when subjected to an external force (corresponding to tooth brushing), the toothbrush filaments of Examples 1, 2, 12, and 13 had output voltages of 1.27 V, 0.89 V, 1.17 V, and 0.79 V, respectively, and antibacterial rates of 77.3%, 52.8%, 77.1%, and 52.7%, whereas Comparative Example 2 had no voltage output and an antibacterial rate of only 9.2%. This shows that the toothbrush filaments manufactured using the manufacturing method of the present invention have stable voltage output when subjected to a dynamic external force, and have good antibacterial performance.

[0041] As can be seen from Table 2, the elastic modulus of the toothbrush filaments in the Examples decreased slightly after annealing and corona polarization using the manufacturing method of the present invention. This may be due to a change in the crystal structure of the piezoelectric polymer due to high-temperature treatment. The elastic modulus is related to the chemical composition and lattice structure of a material. Specifically, as shown in Figure 10, the inventors speculate that the annealing and corona polarization caused most of the α-type in the PVDF of Examples 1 and 2 to melt, leaving insufficient crystalline nuclei to form α-type. At the same time, β-type with high crystallinity and orientation was produced in Examples 1 and 2, and the proportion of β-type was greater than that in Comparative Example 1, while β-type was absent in Comparative Example 2. Furthermore, α-type was present in Examples 12 and 13, but the proportion of β-type was greater than that in Comparative Example 1. Therefore, it was concluded that the improved piezoelectric performance of the toothbrush filaments after annealing and corona polarization using the manufacturing method of the present invention, but the slight decrease in elastic modulus was mainly due to a change in the crystal structure. As shown in Table 2, the elastic modulus of the toothbrush filaments after annealing decreased, but was still higher than that of the nylon material of Comparative Example 2. At the same time, the toothbrush filaments in the present example were used as bristle bundles, and all of them had a tension of 15 N or more and a bending force of less than 6 N, which is soft bristles as specified in the Chinese national standard GB 19342-2013, meets the requirements of the Chinese national standard, and also meets the standards recommended by clinicians.

[0042] Referring to Table 2, it can be seen from Examples 1 to 13 and Comparative Examples 3 to 5 that when the parameters of the annealing treatment and polarization treatment are within the ranges of the present application, the obtained toothbrush filaments have better antibacterial performance, as well as good monofilament bending recovery, tensile strength, elastic modulus, bristle bundle tension and bristle bundle bending force, and meet the requirements of Chinese national standard GB 19342-2013.

[0043] Referring to Table 2, it can be seen from Examples 1, 10 and 11 that the toothbrush filaments manufactured using the piezoelectric polymer of the present application have good antibacterial properties, as well as good monofilament bending recovery, tensile strength, elastic modulus, bristle bundle tension and bristle bundle bending force, and meet the requirements of Chinese national standard GB 19342-2013.

[0044] Specifically, referring to Table 2 and Figure 3, in the antibacterial performance measurement, a higher OD value of the culture medium indicates faster growth of Mutans streptococci and a higher concentration per unit volume, which in turn indicates poorer antibacterial performance of the toothbrush filaments. As shown in Table 2, in the antibacterial performance measurement, the toothbrush filaments of Examples 1 to 13 all had lower OD values ​​of the culture medium after 3 hours of culture with Mutans streptococci than those of Comparative Examples 1 to 5. Furthermore, as shown in Figure 3, after 6, 9, and 12 hours of culture, the OD values ​​of the culture medium in the Examples were still lower than those of the Comparative Examples. This demonstrates that the toothbrush filaments manufactured using the manufacturing method of the present application have good antibacterial performance.

[0045] Specifically, as shown in Figures 4a to 9b, after the toothbrush filaments of Examples 1, 2, 12, 13, Comparative Examples 1 and 2 were co-cultured with Mutans streptococci for 24 hours, as shown in Figures 4a, 4b, 6a and 6b, there was almost no adhesion (i.e., Mutans streptococci) on the surface of the toothbrush filaments of Examples 1 and 12.

[0046] While very small amounts of Streptococcus mutans were present on the surfaces of the toothbrush filaments of Example 2 (shown in area A of FIG. 5b) and Example 13 (shown in area E of FIG. 7b), large amounts of Streptococcus mutans were present on the surfaces of the toothbrush filaments of Comparative Examples 1 and 2 at the same magnification (shown in areas B and C of FIG. 8b and area D of FIG. 9b). In particular, as shown in FIG. 9b, the surface of the toothbrush filament of Comparative Example 2 was almost entirely covered with Streptococcus mutans. This demonstrates that toothbrush filaments manufactured using the manufacturing method of the present application can effectively reduce bacterial growth or proliferation on their surfaces, and in particular, significantly improves the problem of massive bacterial proliferation on their surfaces compared to toothbrush filaments made of general-purpose nylon materials in the prior art. At the same time, when the toothbrush filaments of the present application are applied to a toothbrush, the piezoelectric response of the toothbrush filaments can also effectively remove bacteria from the tooth surface during cleaning, contributing to the improvement of dental diseases such as tooth spot bacteria and periodontal disease.

[0047] The above description is merely a preferred embodiment of the present invention, and the present invention is not limited thereby. Any modifications, equivalent replacements, improvements, etc. made in accordance with the ideas and principles of the present invention are all included within the scope of the present invention.

Claims

[Claim 1] (1) adding a polyvinylidene fluoride piezoelectric polymer having a weight average molecular weight of 150,000 to 300,000 to a melt spinning machine, heating the polymer to its melting temperature, and extruding the polymer to obtain a yarn having a diameter of 175 μm to 265 μm, wherein the piezoelectric polymer has a piezoelectric constant of 10 pC / N to 32 pC / N; (2) Annealing the yarn at 120°C for 1.5h to 3h, and then subjecting it to corona polarization to obtain toothbrush filaments, wherein the corona polarization voltage is 10kV to 50kV, the distance between the electrode and the sample is 10mm to 50mm, the polarization temperature is 25°C to 50°C, and the time is 10min to 60min; or (2') subjecting the thread to corona polarization treatment and then annealing it at 120°C for 1.5h to 3h to obtain toothbrush filaments, the corona polarization treatment being at a voltage of 10kV to 50kV, a distance of 10mm to 50mm, a temperature of 25°C to 50°C, and a time of 10min to 60min; Including, The filament of the toothbrush generates a voltage of 0.6V to 1.5V when subjected to an external force; The toothbrush filament has a monofilament bending recovery rate of 60% to 80%; The antibacterial rate of the toothbrush filaments is 45% to 80%; The method for manufacturing a toothbrush filament, wherein the toothbrush filament has a piezoelectric constant of 0.4 pC / N or more in a stationary state.

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