A quaternary ammonium salt antibacterial dental film and a preparation method thereof

Abstract

The application relates to a quaternary ammonium salt antibacterial dental film and a preparation method thereof, characterized in that the dental film is composed of an outer layer material and an intermediate layer material, the outer layer material is a quaternary ammonium salt antibacterial material, and the intermediate layer material is a polymer material; the outer layer material clamps the intermediate layer material in the middle and is attached together through a hot melt extrusion technology; and the quaternary ammonium salt antibacterial material is a polymer material containing a quaternary ammonium salt antibacterial agent. The quaternary ammonium salt antibacterial dental film provided by the application has the beneficial effects of antibacterial effect, high transparency and easy production. The preparation method has the advantages of convenient operation and being beneficial to large-scale manufacturing.

Description

Technical Field

[0001] This invention relates to the field of dental materials technology, and in particular to a quaternary ammonium salt antibacterial dental film and its preparation method. Background Technology

[0002] The application of computer 3D technology in orthodontics has brought another revolution to the development of oral science. In recent years, a new type of orthodontic technology—invisible aligners—has developed rapidly, solving to some extent the shortcomings of traditional orthodontic techniques. It can be said to be a technological leap in the field of orthodontics. Invisible aligners have solved the problems of unsightly, inconvenient, uncomfortable, difficult to clean, unpredictable results, and high psychological stress on patients associated with traditional orthodontic techniques, and are gradually becoming the first choice for treating dental malocclusion.

[0003] After eating, food debris left in the mouth easily breeds bacteria, which ferment and produce harmful substances, affecting oral health and even causing periodontal disease. Comfortable and aesthetically pleasing clear aligners and invisible aligners are becoming increasingly popular among patients. Current clear aligners and invisible aligners are generally made using dental films. Orthodontic dental films are mainly polymers, such as polyethylene terephthalate (PET), polyethylene terephthalate-1,4-cyclohexanediol (PETG, PCTG), polyurethane (TPU), polycarbonate (PC), polypropylene (PP), and polyamide (PA). However, these materials themselves do not have antibacterial properties. Currently, the dental films used to manufacture clear aligners and invisible aligners on the market do not have antibacterial effects, and there are no effective prevention and treatment methods for periodontal disease caused by wearing clear aligners and invisible aligners.

[0004] Chinese invention patent application "A Long-lasting Antibacterial Material and Its Preparation Method, a Long-lasting Antibacterial Dental Film and a Long-lasting Antibacterial Invisible Orthodontic Appliance", patent application number: 202010062403.4, describes a process of tertiary ammoniumization and in-situ quaternization of polyurethane (TPU) on a substrate surface. This process grafts quaternary ammonium salt antibacterial groups into the molecular structure of the substrate surface, thereby giving the material a stable and long-lasting antibacterial effect. However, this process is carried out in a solvent and involves a direct chemical reaction on the surface of the film or invisible orthodontic appliance, which may damage the material's performance. In addition, this method is only applicable to polyurethane and the process is relatively complex, thus limiting its application.

[0005] Chinese invention patent application "A Novel Antibacterial Braces and Its Preparation Method", application number: 202010147876.4, describes a novel antibacterial braces and its preparation method. The braces are formed by sequentially stacking a first film and a second film. The surface of the braces body that contacts the teeth is the first film, and the surface of the braces body that faces away from the teeth is the second film. Since the antibacterial and non-antibacterial films are formed into a composite film by bonding, the prepared braces are prone to delamination. At the same time, the antibacterial particles in this patent are one or a mixture of nano-zinc oxide and silver particles. Silver ions are easily oxidized and turn black, thus affecting the aesthetics and "invisible" effect of the braces.

[0006] Given the aforementioned shortcomings of existing dental films, this invention develops a novel quaternary ammonium salt antibacterial dental film and its preparation method. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a dental membrane that has both antibacterial effect and high transparency, and is easy to manufacture.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a quaternary ammonium salt antibacterial dental membrane, characterized in that: the dental membrane is composed of an outer layer material and an intermediate layer material, the outer layer material is a quaternary ammonium salt antibacterial material, and the intermediate layer material is a polymer material; the outer layer material sandwiches the intermediate layer material in the middle and is bonded together by hot melt extrusion technology; the quaternary ammonium salt antibacterial material is a polymer material containing a quaternary ammonium salt antibacterial agent.

[0009] The polymer material is one of polyethylene terephthalate (PET), polyethylene terephthalate-1,4-cyclohexanediethanol (PETG, PCTG), polyurethane (TPU), polycarbonate (PC), or a mixture thereof in any proportion.

[0010] The polymer material has a Shore hardness ≥40HD, tear strength ≥200KN / m, yield strength ≥20MPa, and transparency ≥70%.

[0011] As a preferred embodiment of the present invention, the polymer material has a Shore hardness ≥60HD, tear strength ≥240KN / m, yield strength ≥30MPa, and transparency ≥80%.

[0012] The outer layer material has a thickness of 10-50% of the dental membrane thickness, and it covers the outside of the intermediate layer material, preferably 10-30%. The thickness of the outer layer material can be routinely adjusted during the manufacturing process using extrusion equipment.

[0013] The quaternary ammonium salt antibacterial agent is one of organosilicon quaternary ammonium salt, montmorillonite quaternary ammonium salt, chitosan quaternary ammonium salt, or a mixture thereof in any proportion.

[0014] Furthermore, as a preferred embodiment of the present invention, the quaternary ammonium salt antibacterial agent is one of organosilicon quaternary ammonium salt or chitosan quaternary ammonium salt.

[0015] The particle size of the quaternary ammonium salt antibacterial agent is ≤5µm, preferably ≤1µm.

[0016] This invention also provides a method for preparing a quaternary ammonium salt antibacterial dental film, characterized by the following steps:

[0017] A. The polymer material is pulverized into particles with a diameter ≤0.5mm. Then, the obtained polymer material particles are mixed with a quaternary ammonium salt antibacterial agent at a mass ratio of 40-80:60-20. After mixing, the mixture is dried at a temperature of 60-110℃ for 4-12 hours. Then, it is fed into a twin-screw granulator for extrusion granulation to obtain quaternary ammonium salt antibacterial masterbatch. The polymer material is one of polyethylene terephthalate (PET), polyethylene terephthalate-1,4-cyclohexanediol (PETG, PCTG), polyurethane (TPU), and polycarbonate (PC), or a mixture thereof in any proportion. The quaternary ammonium salt antibacterial agent is one of organosilicon quaternary ammonium salt, montmorillonite quaternary ammonium salt, and chitosan quaternary ammonium salt, or a mixture thereof in any proportion.

[0018] B. Weigh out the polymer material and quaternary ammonium salt antibacterial masterbatch at a mass ratio of 90-99:10-1 and mix them. After mixing, dry the mixture. The drying dew point should be below -30℃, the drying temperature should be 60-110℃, and the drying time should be 4-12 hours. The dried mixture is used as the outer layer material. In addition, take an appropriate amount of polymer material, dry it, and use it as the middle layer material.

[0019] C. Load the outer layer material and the middle layer material into the extrusion equipment, set the outer layer extrusion temperature to 160-220℃, the middle layer extrusion temperature to 160-220℃, and extrusion molding to obtain the quaternary ammonium salt antibacterial dental film.

[0020] The extrusion equipment is a three-layer co-extrusion equipment. The thickness of the outer layer material and the intermediate layer material can be adjusted as needed.

[0021] The main antibacterial component of the quaternary ammonium salt antibacterial agent is quaternary ammonium salt, which is characterized by its low price and fast bactericidal speed. However, small-molecule quaternary ammonium salts generally have disadvantages such as poor chemical stability and easy elution. The quaternary ammonium salt antibacterial agent used in this invention is a chemical reaction that immobilizes small-molecule quaternary ammonium salts on organosilicon, montmorillonite, graphene, and chitosan, which enables the quaternary ammonium salts to have better high-temperature resistance and long-lasting antibacterial effect. The organosilicon quaternary ammonium salt, montmorillonite quaternary ammonium salt, and chitosan quaternary ammonium salt are all commercially available products.

[0022] This invention utilizes organosilicon quaternary ammonium salts, montmorillonite quaternary ammonium salts, and chitosan quaternary ammonium salts as high-temperature resistant quaternary ammonium salt antibacterial agents. The quaternary ammonium salt antibacterial agents are mixed with polymer materials to prepare quaternary ammonium salt antibacterial masterbatches. These masterbatches are then added to the polymer materials to prepare an outer layer material with antibacterial properties. On one hand, the selected quaternary ammonium salt antibacterial agents are harmless to the human body and possess excellent antibacterial effects; on the other hand, the physical blending process of the quaternary ammonium salt antibacterial agents and polymer materials is mature, convenient to operate, and conducive to large-scale production.

[0023] Adding opaque antibacterial agents to transparent resins via thermal mixing reduces the material's transparency. Besides factors inherent to the resin itself, the main reasons affecting transparency are the antibacterial agent content and its particle size within the polymer. This invention, by selecting specific quaternary ammonium salts and polymers in a specific mass ratio, combined with an encapsulation structure, produces a quaternary ammonium salt antibacterial dental membrane that exhibits both effective antibacterial properties and high transparency.

[0024] In summary, this invention has the following advantages: it possesses both antibacterial properties and high transparency, and is easy to manufacture. The preparation method is convenient and conducive to large-scale production. Attached Figure Description

[0025] Figure 1 This is a schematic cross-sectional view of the quaternary ammonium salt antibacterial dental membrane described in this invention;

[0026] Figure 2 This is a schematic diagram of the preparation process of the quaternary ammonium salt antibacterial masterbatch described in this invention;

[0027] Figure 3 This is a schematic diagram of the antibacterial membrane preparation process described in this invention. Detailed Implementation

[0028] The technical solution of the present invention will be further described in detail below through specific embodiments.

[0029] Example 1: A method for preparing a quaternary ammonium salt antibacterial dental film, characterized by the following steps: A. Pulverizing a polymer material into particles with a diameter ≤0.5mm, then mixing the obtained polymer material particles with an organosilicon quaternary ammonium salt antibacterial agent at a mass ratio of 70:30, drying the mixture at a temperature of 95℃ for 10 hours; then extruding and granulating the mixture into a twin-screw extruder to obtain a quaternary ammonium salt antibacterial masterbatch; the polymer material is polyurethane (TPU); B. Weighing the polymer material and the quaternary ammonium salt antibacterial masterbatch at a mass ratio of 96:4, mixing the mixture, drying the mixture at a dew point of -40℃, a temperature of 95℃ for 10 hours, the dried mixture is the outer layer material, and separately weighing an appropriate amount of polymer material as the intermediate layer material, the polymer material being polyurethane (TPU);

[0030] C. Load the outer layer material and the middle layer material into a three-layer co-extrusion machine, set the outer layer extrusion temperature to 180-220℃, and the middle layer extrusion temperature to 180-220℃, and extrude to obtain a quaternary ammonium salt antibacterial dental film. Figure 1 As shown, the outer layer material 1 covers the middle layer material 2.

[0031] Example 2: A method for preparing a quaternary ammonium salt antibacterial dental film, characterized by the following steps:

[0032] A. The polymer material is crushed into particles with a diameter ≤0.5mm. Then, the obtained polymer material particles are mixed with montmorillonite quaternary ammonium salt antibacterial agent at a mass ratio of 80:20. After mixing, the mixture is dried at a temperature of 75℃ for 8 hours. Then, it is loaded into a twin-screw granulator for extrusion granulation to obtain quaternary ammonium salt antibacterial masterbatch. The polymer material is polyethylene terephthalate-1,4-cyclohexanediol ester (PCTG).

[0033] B. Weigh out the polymer material and quaternary ammonium salt antibacterial masterbatch at a mass ratio of 94:6, mix them, and dry them at a dew point of -40℃, a drying temperature of 75℃, and a drying time of 8 hours. The dried mixture is the outer layer material. Separately weigh out an appropriate amount of polymer material as the intermediate layer material. The polymer material is polyethylene terephthalate-1,4-cyclohexanediol ester (PCTG). C. Load the outer layer material and the intermediate layer material into a three-layer co-extrusion machine. Set the outer layer extrusion temperature to 160-200℃ and the intermediate layer extrusion temperature to 160-220℃. Extrusion molding yields the quaternary ammonium salt antibacterial dental film. Figure 1 As shown, the outer layer material 1 covers the middle layer material 2.

[0034] Example 3: A method for preparing a quaternary ammonium salt antibacterial dental film, characterized by the following steps:

[0035] A. The polymer material is pulverized into particles with a diameter ≤0.5mm. Then, the obtained polymer material particles are mixed with chitosan quaternary ammonium salt antibacterial agent at a mass ratio of 60:40. After mixing, the mixture is dried at 60℃ for 8 hours. Then, it is loaded into a twin-screw granulator for extrusion granulation to obtain quaternary ammonium salt antibacterial masterbatch. The polymer material is polyethylene terephthalate-1,4-cyclohexanediol ester (PETG).

[0036] B. Weigh out the polymer material and quaternary ammonium salt antibacterial masterbatch at a mass ratio of 97:3, mix them, and dry them at a dew point of -30℃, a drying temperature of 60℃, and a drying time of 8 hours. The dried mixture is the outer layer material. Separately weigh out an appropriate amount of polymer material as the intermediate layer material. The polymer material is polyethylene terephthalate-1,4-cyclohexanediol ester (PETG). C. Load the outer layer material and the intermediate layer material into a three-layer co-extrusion machine. Set the outer layer extrusion temperature to 160-200℃ and the intermediate layer extrusion temperature to 160-200℃. Extrusion molding yields the quaternary ammonium salt antibacterial dental film. Figure 1 As shown, the outer layer material 1 covers the middle layer material 2.

[0037] Table 1: Components and their contents in different embodiments

[0038] resin TPU PCTG PETG Types of antibacterial agents Organosilicon quaternary ammonium salts Montmorillonite quaternary ammonium salt Chitosan Quaternary Ammonium Salt Diaphragm thickness (mm) 1 1 1 Antibacterial layer thickness (single layer: mm) 0.15 0.10 0.15 mass ratio of resin to antibacterial agent 70:30 80:20 60:40 mass ratio of resin to masterbatch 96:4 94:6 97:3

[0039] The samples prepared in Examples 1-3 were evaluated according to the following methods:

[0040] (1) Antibacterial properties: The antibacterial properties of the membrane were tested according to QB / T 2591—2003 using the membrane application method, and the antibacterial membrane was examined for its inhibition rate after 24 hours of contact with the test bacteria (Staphylococcus aureus).

[0041] (2) Transmittance / Haze: Test the transmittance and haze of the membrane according to the method described in GBT2410-2008.

[0042] The results of the above tests are shown in Table 2.

[0043] Table 2: Performance test results for different embodiments

[0044] Example 1 99 91.2 2.7 Example 2 99 90.6 3.2 Example 3 99 90.2 3.6

[0045] As shown in Table 2, in the examples of quaternary ammonium salt antibacterial dental films, the antibacterial rate reached 99% after 24 hours; and it also had good transparency.

[0046] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A method for preparing a quaternary ammonium salt antibacterial dental film, characterized in that... The following steps are adopted: A. The polymer material is pulverized into particles with a diameter ≤0.5mm. Then, the obtained polymer material particles are mixed with a quaternary ammonium salt antibacterial agent at a mass ratio of 40-80:60-20. After mixing, the mixture is dried at a temperature of 60-110℃ for 4-12 hours. Then, it is fed into a twin-screw granulator for extrusion granulation to obtain quaternary ammonium salt antibacterial masterbatch. The polymer material is one of polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanediol, polyurethane, and polycarbonate, or any mixture thereof in any proportion. The quaternary ammonium salt antibacterial agent is one of organosilicon quaternary ammonium salt, montmorillonite quaternary ammonium salt, and chitosan quaternary ammonium salt, or any mixture thereof in any proportion. B. Weigh out the polymer material and quaternary ammonium salt antibacterial masterbatch at a mass ratio of 90-99:10-1 and mix them. After mixing, dry the mixture. The drying dew point should be below -30℃, the drying temperature should be 60~110℃, and the drying time should be 4~12h. The dried mixture is used as the outer layer material. In addition, take an appropriate amount of polymer material, dry it, and use it as the middle layer material. C. Load the outer layer material and the middle layer material into the extrusion equipment, set the outer layer extrusion temperature to 160-220℃, the middle layer extrusion temperature to 160-220℃, and extrusion molding to obtain the quaternary ammonium salt antibacterial dental film.

2. The method for preparing a quaternary ammonium salt antibacterial dental film according to claim 1, characterized in that: The polymer material has a Shore hardness ≥40HD, tear strength ≥200 KN / m, yield strength ≥20MPa, and transparency ≥70%.

3. The method for preparing a quaternary ammonium salt antibacterial dental film according to claim 1, characterized in that: The outer layer material has a thickness of 10-50% of the dental membrane thickness, and it covers the outside of the intermediate layer material.

4. The method for preparing a quaternary ammonium salt antibacterial dental film according to claim 3, characterized in that: The thickness of the outer layer material is 10-30% of the thickness of the dental membrane.

5. The method for preparing a quaternary ammonium salt antibacterial dental film according to claim 1, characterized in that: The particle size of the quaternary ammonium salt antibacterial agent is less than ≤5 μm.

6. The method for preparing a quaternary ammonium salt antibacterial dental film according to claim 5, characterized in that: The particle size of the quaternary ammonium salt antibacterial agent is less than 1 μm.

7. A quaternary ammonium salt antibacterial dental film, characterized in that: Dental membrane prepared by the method described in any one of claims 1 to 6.

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