A method of producing a sterile toothbrush

Abstract

The application provides a production method of a sterile toothbrush, and the production method comprises the following steps: a brush head production step, a brush handle production step, an assembling step of assembling the brush head and the brush handle, a toothbrush forming step, an ethylene oxide sterilization step or an irradiation sterilization step. The production method of the sterile toothbrush combines multiple sterilization technologies, reduces production cost and energy consumption while ensuring sterilization effect, and reduces the influence of the sterilization process on the service life of the toothbrush.

Description

Technical Field

[0001] This invention relates to the field of toothbrush manufacturing, and more specifically, to a method for producing a sterile toothbrush. Background Technology

[0002] Toothbrush production mainly consists of two parts: the brush head and the handle, which are then assembled into the finished product. The primary manufacturing process is injection molding. Polypropylene (PP) and polycarbonate (PC) plastic raw materials are heated and melted, then injected into a mold. After cooling, the handle is demolded. Some high-end handles incorporate anti-slip textures, patterns, or antibacterial components during injection molding. Brush head production mainly includes bristle implantation and one-piece injection molding. Bristle implantation involves cutting the toothbrush bristles to a specified length and then implanting them into a pre-drilled hole in the brush head base using a bristle implantation machine. Common bristle implantation methods include drilled bristle implantation and non-drilled bristle implantation (hot-melt bristle implantation). One-piece injection molding involves placing the toothbrush bristles and the plastic raw material of the brush head base into a mold together and molding them in one step using an injection molding machine. This method is highly efficient, resulting in a tight bond between the brush head and bristles without gaps, making it less prone to dirt accumulation.

[0003] There are many existing toothbrush manufacturing methods, such as the toothbrush and its manufacturing method disclosed in Chinese Patent CN1220854A and the toothbrush and its manufacturing method disclosed in Chinese Patent CN120616242A. In order to ensure the quality of toothbrush production, sterilization treatment needs to be ensured during the toothbrush production process. However, these toothbrush manufacturing methods do not take into account the application of sterilization methods during the toothbrush production process.

[0004] In order to solve the above problems, people have been seeking an ideal technological solution. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for producing a sterile toothbrush.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for producing a sterile toothbrush, comprising the following steps: a. Brush head production; b. Brush handle production; c. Assembly of brush head and brush handle to form a toothbrush; d. Place the toothbrush into the sterilized packaging bag, heat seal it, spray code the packaged toothbrush to mark the production date, batch number and shelf life, and then sterilize it. The sterilization process is performed using ethylene oxide sterilization or gamma ray irradiation sterilization. The packaging bag used in ethylene oxide sterilization is a composite bag with dialysis paper for ethylene oxide sterilization. The sterilization method for ethylene oxide is as follows: the packaging bag containing the toothbrush is placed in a sterilization chamber using a mixed gas at a concentration of 750-850 mg / L, a temperature of 30-40℃, a relative humidity of 65%-75%, and a sterilization time of 1-3 hours. After sterilization, the toothbrush is placed in a ventilated desorption chamber at 25℃ under ventilated conditions for 1-3 days to ensure that the residual ethylene oxide content is ≤0.5μg / g. The mixed gas includes 8%-30% ethylene oxide and 70%-92% carbon dioxide. The method of sterilization by gamma ray irradiation is as follows: irradiate with gamma rays generated by a cobalt-60 source in an environment of 10-20℃ and relative humidity ≤40% for 30-60 minutes.

[0007] The bristles are made of nylon 612 or PBT material with a tensile strength of 30-60 MPa and an elongation at break of 150-300%, and a diameter of 0.15-0.2 mm; the brush head base and brush handle are made of plastic material with a tensile strength of 20-80 MPa and a flexural modulus of 1000-3500 MPa.

[0008] Place the rolled brush bristles into the sterilization chamber, evacuate the chamber to reduce the pressure to below -0.08 MPa, then fill the chamber with saturated steam to raise the pressure to 0.02 MPa. Evacuate the chamber again to reduce the pressure to below -0.08 MPa. Repeat this vacuum-steam cycle three times, filling the chamber with saturated steam to 0.07-0.1 MPa. Sterilize at 110-120℃ for 20-30 minutes, then dry in an oven.

[0009] The raw material particles for the brush head base and the brush handle are placed into a drying and sterilization machine and sterilized at 150-160℃ for 2 hours. Then, they are injection molded to obtain the brush handle base and the brush head.

[0010] The injection molding process is used to inject sterilized raw material granules into the mold. The molding temperature is controlled at 180-230℃ and the cooling time is 20-50 seconds. The brush handle and brush head base are ground and polished to remove burrs and sharp edges.

[0011] The brush head is implanted with sterilized nylon bristles using a hot-melt bristle implantation process. The bristle density is controlled at 30-40 bristles / cm2. After the bristle implantation is completed, the brush head is cleaned with an ultrasonic cleaner to remove debris.

[0012] First, rinse the brush head with pure water, then use a cleaning solution to ultrasonically clean the brush head, rinse with pure water again, and then dry.

[0013] The cleaning temperature for pure water rinsing and ultrasonic cleaning is 40-50℃, and ultrasonic cleaning is carried out at 40-60kHz and 0.2-0.7W / cm2. The cleaning solution includes pure water and surfactant, and the mass fraction of surfactant is 1%-5%.

[0014] The brush head and brush handle are assembled together by ultrasonic welding, with a welding strength ≥50N.

[0015] The brush head and handle are welded using an ultrasonic welding machine with a frequency of 15-20 kHz and a power of 1500-2000 W. The amplitude is 30-50 μm, the welding pressure is 0.2-0.5 MPa, the welding time is 0.3-0.8 seconds, the holding time is 0.1-0.5 seconds, and the penetration depth is 0.5-1.0 mm.

[0016] This invention represents a significant advancement and substantial improvement over existing technologies. Specifically, it provides a method for producing sterile toothbrushes that combines multiple sterilization technologies to reduce production costs and energy consumption while ensuring effective sterilization. Specifically, it employs pulsed vacuum moist heat sterilization to treat the bristle raw materials. The vacuum exhaust design lowers the sterilization temperature, improves sterilization uniformity, and reduces plastic thermal aging caused by high temperatures. Furthermore, it uses an EO / CO2 mixed gas to sterilize the semi-finished product, which not only shortens the sterilization time and desorption time but also reduces the impact of ethylene oxide on the toothbrush's lifespan. Detailed Implementation

[0017] The technical solution of the present invention will be further described in detail below through specific embodiments. Example 1

[0018] This embodiment provides a method for producing a sterile toothbrush, which includes the following steps: Place the brush bristles into the sterilization chamber, evacuate the chamber to reduce the pressure to below -0.08 MPa, then fill the chamber with saturated steam to raise the pressure to 0.02 MPa. Evacuate the chamber again to reduce the pressure to below -0.08 MPa. Repeat this vacuum-steam cycle three times, filling the chamber with saturated steam to 0.07 MPa. Sterilize at 115°C for 30 minutes, then dry in an oven at 60°C.

[0019] The bristles are made of nylon 612 with a tensile strength of 50MPa, an elongation at break of 260%, and a diameter of 0.15 mm. The raw material granules for the brush head base and brush handle are placed separately into a drying and sterilization integrated machine and sterilized at 150-160℃ for 2 hours. Then, they are injection molded to obtain the brush handle base and brush head. The raw material granules are PBT plastic with a tensile strength of 60 MPa and a flexural modulus of up to 2500 MPa.

[0020] The sterilized raw material granules are injected into the mold using an injection molding process. The molding temperature is controlled at 220-230℃, and the cooling time is 30 seconds to form the brush handle and brush head base. The brush handle and brush head base are then ground and polished to remove burrs and sharp edges.

[0021] Using a hot-melt tufting process, sterilized nylon 612 is implanted into the brush head base, with the tufting density controlled at 30-40 tufts / cm. 2 After bristle implantation, the brush head is cleaned at 40-50℃. First, rinse the brush head with pure water to initially remove visible plastic debris and bristle lint. Then, use a 40kHz, 0.5W / cm brush head... 2 Ultrasonic cleaning for 2 minutes removes residual hot melt adhesive and plastic debris from the hair grafting process; then, at a frequency of 60kHz and a pressure of 0.3W / cm², the cleaning is repeated. 2 The ultrasonic cleaning process lasts for 2 minutes, followed by a final rinse with pure water and drying. The ultrasonic cleaning solution consists of pure water and sodium dodecyl sulfate (NDS), with NDS comprising 2% by mass.

[0022] The brush head and handle are assembled together using ultrasonic welding to obtain a toothbrush with a weld strength ≥50N. Specifically, an ultrasonic welding machine with a frequency of 15 kHz and a power of 2000 W is used to weld the brush head and handle. The amplitude is 40 μm, the welding pressure is 0.35 MPa, the welding time is 0.5 seconds, the holding time is 0.2 seconds, and the penetration depth is 0.7 mm.

[0023] The toothbrushes are placed in sterilized packaging bags, heat-sealed, and then the packaged toothbrushes are marked with production date, batch number, and shelf life. They are then sterilized. Specifically, the packaging bags are composite bags, with one side being a PE composite film and the other side being dialysis paper.

[0024] After packaging, the toothbrushes are placed in a sterilization chamber and sterilized using a mixed gas at a concentration of 800 mg / L, a temperature of 30-40℃, a relative humidity of 70%, and a sterilization time of 2 hours. After sterilization, the toothbrushes are placed in a ventilated desorption chamber and placed at 25℃ under ventilated conditions for 1 day to ensure that the residual ethylene oxide content is ≤0.5μg / g. The mixed gas consists of 8% ethylene oxide and 92% carbon dioxide. Example 2

[0025] This embodiment provides a method for producing a sterile toothbrush, which includes the following steps: Place the brush bristles into the sterilization chamber, evacuate the chamber to reduce the pressure to below -0.08 MPa, then fill the chamber with saturated steam to raise the pressure to 0.02 MPa. Evacuate the chamber again to reduce the pressure to below -0.08 MPa. Repeat this vacuum-steam cycle three times, filling the chamber with saturated steam to 0.09 MPa. Sterilize at 115°C for 30 minutes, then dry in an oven at 60°C.

[0026] The bristles are made of nylon 612 with a tensile strength of 50MPa, an elongation at break of 260%, and a diameter of 0.15 mm. The raw material granules for the brush head base and brush handle are placed separately into a drying and sterilization integrated machine and sterilized at 150-160℃ for 2 hours. Then, they are injection molded to obtain the brush handle base and brush head. The raw material granules are PBT plastic with a tensile strength of 60 MPa and a flexural modulus of up to 2500 MPa.

[0027] The sterilized raw material granules are injected into the mold using an injection molding process. The molding temperature is controlled at 220-230℃, and the cooling time is 30 seconds to form the brush handle and brush head base. The brush handle and brush head base are then ground and polished to remove burrs and sharp edges.

[0028] Using a hot-melt tufting process, sterilized nylon 612 is implanted into the brush head base, with the tufting density controlled at 30-40 tufts / cm. 2 After bristle implantation, the brush head is cleaned at 40-50℃. First, rinse the brush head with pure water to initially remove visible plastic debris and bristle lint. Then, use a 45kHz, 0.5W / cm brush head... 2 Ultrasonic cleaning for 4 minutes removes residual hot melt adhesive and plastic debris from the hair grafting process; then, at a frequency of 60kHz and a pressure of 0.3W / cm², the cleaning is repeated. 2 The ultrasonic cleaning process lasts for 4 minutes, followed by a final rinse with pure water and drying. The ultrasonic cleaning solution consists of pure water and sodium dodecyl sulfate (NDS), with a sodium dodecyl sulfate mass fraction of 3%.

[0029] The brush head and handle are assembled together using ultrasonic welding to obtain a toothbrush with a weld strength ≥50N. Specifically, an ultrasonic welding machine with a frequency of 15 kHz and a power of 2000 W is used to weld the brush head and handle. The amplitude is 40 μm, the welding pressure is 0.35 MPa, the welding time is 0.5 seconds, the holding time is 0.2 seconds, and the penetration depth is 0.7 mm.

[0030] The toothbrushes are placed in sterilized PE composite film packaging bags, heat-sealed, and then the packaged toothbrushes are marked with production date, batch number and shelf life by inkjet printing, and then packed into boxes.

[0031] After packaging, the samples were irradiated with gamma rays generated by a cobalt-60 source at an environment of 10-20℃ and relative humidity ≤40% for 40 minutes. Example 3

[0032] This embodiment provides a method for producing a sterile toothbrush, which includes the following steps: Place the brush bristles into the sterilization chamber, evacuate the chamber to reduce the pressure to below -0.08 MPa, then fill the chamber with saturated steam to raise the pressure to 0.02 MPa. Evacuate the chamber again to reduce the pressure to below -0.08 MPa. Repeat this vacuum-steam cycle three times, filling the chamber with saturated steam to 0.10 MPa. Sterilize at 115°C for 20 minutes, then dry in an oven at 60°C.

[0033] The bristles are made of nylon 612 with a tensile strength of 50MPa, an elongation at break of 260%, and a diameter of 0.15 mm. The raw material granules for the brush head base and brush handle are placed separately into a drying and sterilization integrated machine and sterilized at 150-160℃ for 2 hours. Then, they are injection molded to obtain the brush handle base and brush head. The raw material granules are PBT plastic with a tensile strength of 60 MPa and a flexural modulus of up to 2500 MPa.

[0034] The sterilized raw material granules are injected into the mold using an injection molding process. The molding temperature is controlled at 220-230℃, and the cooling time is 30 seconds to form the brush handle and brush head base. The brush handle and brush head base are then ground and polished to remove burrs and sharp edges.

[0035] Using a hot-melt tufting process, sterilized nylon 612 is implanted into the brush head base, with the tufting density controlled at 30-40 tufts / cm. 2 After bristle implantation, the brush head is cleaned at 40-50℃. First, rinse the brush head with pure water to initially remove visible plastic debris and bristle lint. Then, use a 40kHz, 0.5W / cm brush head... 2 Ultrasonic cleaning for 5 minutes removes residual hot melt adhesive and plastic debris from the hair grafting process; then, at a frequency of 60kHz and a pressure of 0.3W / cm², the cleaning is repeated. 2 The ultrasonic cleaning process lasts for 5 minutes, followed by a final rinse with pure water and drying. The ultrasonic cleaning solution consists of pure water and sodium dodecyl sulfate (NDS), with a sodium dodecyl sulfate mass fraction of 3%.

[0036] The brush head and handle are assembled together using ultrasonic welding to obtain a toothbrush with a weld strength ≥50N. Specifically, an ultrasonic welding machine with a frequency of 15 kHz and a power of 2000 W is used to weld the brush head and handle. The amplitude is 40 μm, the welding pressure is 0.35 MPa, the welding time is 0.5 seconds, the holding time is 0.2 seconds, and the penetration depth is 0.7 mm.

[0037] The toothbrushes are placed in sterilized PE composite film packaging bags, heat-sealed, and then the packaged toothbrushes are marked with production date, batch number and shelf life by inkjet printing, and then packed into boxes.

[0038] After packaging, the samples were irradiated with gamma rays generated by a cobalt-60 source at an environment of 10-20℃ and relative humidity ≤40% for 60 minutes.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for producing a sterile toothbrush, comprising the following steps: a. Brush head production; b. Brush handle production; c. Assembly of brush head and brush handle to form a toothbrush; d. Place the toothbrush into the sterilized packaging bag, heat seal it, spray code the packaged toothbrush to mark the production date, batch number and shelf life, and then sterilize it. Sterilization is performed using ethylene oxide sterilization or gamma ray irradiation sterilization. The packaging bag used in ethylene oxide sterilization is a composite bag with dialysis paper for ethylene oxide sterilization. The sterilization method for ethylene oxide is as follows: the packaging bag containing the toothbrush is placed in a sterilization chamber using a mixed gas at a concentration of 750-850 mg / L, a temperature of 30-40℃, a relative humidity of 65%-75%, and a sterilization time of 1-3 hours. After sterilization, the toothbrush is placed in a ventilated desorption chamber at 25℃ under ventilated conditions for 1-3 days to ensure that the residual ethylene oxide content is ≤0.5μg / g. The mixed gas includes 8%-30% ethylene oxide and 70%-92% carbon dioxide. The method of sterilization by gamma ray irradiation is as follows: irradiate with gamma rays generated by a cobalt-60 source in an environment of 10-20℃ and relative humidity ≤40% for 30-60 minutes.

2. The method for producing a sterile toothbrush according to claim 1, characterized in that: The bristles are made of nylon 612 or PBT material with a tensile strength of 30-60 MPa and an elongation at break of 150-300%, and a diameter of 0.15-0.2 mm; the brush head base and brush handle are made of plastic material with a tensile strength of 20-80 MPa and a flexural modulus of 1000-3500 MPa.

3. The method for producing a sterile toothbrush according to claim 2, characterized in that: Place the rolled brush bristles into the sterilization chamber, evacuate the chamber to reduce the pressure to below -0.08 MPa, then fill the chamber with saturated steam to raise the pressure to 0.02 MPa. Evacuate the chamber again to reduce the pressure to below -0.08 MPa. Repeat this vacuum-steam cycle three times, filling the chamber with saturated steam to 0.07-0.1 MPa. Sterilize at 110-120℃ for 20-30 minutes, then dry in an oven.

4. The method for producing a sterile toothbrush according to claim 3, characterized in that: The raw material particles for the brush head base and the brush handle are placed into a drying and sterilization machine and sterilized at 150-160℃ for 2 hours. Then, they are injection molded to obtain the brush handle base and the brush head.

5. The method for producing a sterile toothbrush according to claim 4, characterized in that: The injection molding process is used to inject sterilized raw material granules into the mold. The molding temperature is controlled at 180-230℃ and the cooling time is 20-50 seconds. The brush handle and brush head base are ground and polished to remove burrs and sharp edges.

6. The method for producing a sterile toothbrush according to claim 5, characterized in that: A hot-melt bristle implantation process is used to implant sterilized nylon bristles into the brush head base, with the bristle density controlled at 30-40 bristles / cm². 2 After the bristles are implanted, the brush head is cleaned with an ultrasonic cleaner to remove debris.

7. The method for producing a sterile toothbrush according to claim 6, characterized in that: First, rinse the brush head with pure water, then use a cleaning solution to ultrasonically clean the brush head, rinse with pure water again, and then dry.

8. The method for producing a sterile toothbrush according to claim 7, characterized in that: The cleaning temperature for pure water rinsing and ultrasonic cleaning is 40-50℃, at 40-60kHz, and 0.2-0.7W / cm². 2 Ultrasonic cleaning is performed under the following conditions: the cleaning solution consists of pure water and a surfactant, with the surfactant having a mass fraction of 1%-5%.

9. The method for producing a sterile toothbrush according to claim 8, characterized in that: The brush head and brush handle are assembled together by ultrasonic welding, with a welding strength ≥50N.

10. The method for producing a sterile toothbrush according to claim 9, characterized in that: The brush head and handle are welded using an ultrasonic welding machine with a frequency of 15-20 kHz and a power of 1500-2000 W. The amplitude is 30-50 μm, the welding pressure is 0.2-0.5 MPa, the welding time is 0.3-0.8 seconds, the holding time is 0.1-0.5 seconds, and the penetration depth is 0.5-1.0 mm.