Denture soft lining silicone rubber based on dynamic covalent bonds as well as preparation method and application of denture soft lining silicone rubber

Abstract

The invention discloses false tooth soft lining silicone rubber based on dynamic covalent bonds and a preparation method and application thereof, and belongs to the technical field of synthesis of false tooth soft lining silicone rubber. The invention provides a preparation method of false tooth soft lining silicone rubber based on dynamic covalent bonds, which comprises the following steps: in an organic solvent, reacting binary isocyanate with aminopropyl-terminated polydimethylsiloxane to generate isocyanate-terminated polydimethylsiloxane so as to obtain a reaction solution; and adding binary thiol into the reaction liquid, and reacting the isocyanate-terminated polydimethylsiloxane with the binary thiol to generate a dynamic thiocarbamate bond, thereby obtaining the false tooth soft lining silicone rubber. The preparation steps are simple, and the prepared false tooth soft lining silicone rubber is good in mechanical property and has the characteristics of self-healing, self-adhesion, 3D printing and cyclic utilization.

Description

Technical Field

[0001] The present invention relates to the technical field of the synthesis of denture soft lining silicone rubber, and more specifically to a denture soft lining silicone rubber based on dynamic covalent bonds, its preparation method and application. Background Art

[0002] Denture soft lining materials, also known as elastic denture lining materials, are a type of denture lining materials used on the tissue surface of denture bases and having a certain elasticity after curing. Lining an elastic material on the tissue surface of the denture base can, on the one hand, improve the tightness between the denture base and the alveolar ridge through the elastic deformation of the elastic lining material, thereby improving the retention of the denture; on the other hand, through elastic deformation, it can buffer the impact bite force, enabling the bite force borne by the denture to be evenly transmitted to the alveolar ridge, avoiding excessive local pressure, and thus reducing or eliminating tenderness.

[0003] The performance requirements of modern materials tend to be more complex and integrated. For various artificially synthesized elastic polymer materials, various characteristics have been developed and realized, including good mechanical properties, self-healing, self-adhesion, 3D printing ability, and recyclability. However, it is difficult to concentrate these properties in the same elastic polymer, which often leads to a complex structure, high synthesis difficulty, and high preparation cost of the denture soft lining silicone rubber. Moreover, there may be mutual influences between different properties and between new properties and existing properties. For example, the elastic materials currently used in 3D printing are covalently crosslinked after curing, resulting in problems such as non-recyclability, non-remoldability, and low mechanical properties, causing great pollution to the environment. Summary of the Invention

[0004] In view of the above problems, the present invention provides a denture soft lining silicone rubber based on dynamic covalent bonds, its preparation method and application. The preparation steps of the present invention are simple, and the prepared denture soft lining silicone rubber has good mechanical properties and has the characteristics of self-healing, self-adhesion, 3D printing ability, and recyclability.

[0005] The first object of the present invention is to provide a preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds, which is characterized by including the following steps: In an organic solvent, a diisocyanate and an aminopropyl-terminated polydimethylsiloxane react to form an isocyanate-terminated polydimethylsiloxane, obtaining a reaction solution; A dithiol is added to the reaction solution, and the isocyanate-terminated polydimethylsiloxane reacts with the dithiol to form a dynamic thiocarbamate bond, thereby preparing the denture soft lining silicone rubber.

[0006] In a preferred embodiment of the present invention, the molar ratio of the diisocyanate to the aminopropyl-terminated polydimethylsiloxane is 1 to 4:1. For example, the molar ratio of the diisocyanate to the aminopropyl-terminated polydimethylsiloxane can be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0007] In a preferred embodiment of the present invention, the reaction for preparing the reaction solution is carried out at room temperature for 0.5 h to 3 h. For example, the reaction can be carried out at room temperature for 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0008] In a preferred embodiment of the present invention, the molar ratio of the isocyanate group-terminated polydimethylsiloxane to the dithiol is 1 to 1.5:1. For example, the molar ratio of the isocyanate group-terminated polydimethylsiloxane to the dithiol can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0009] In a preferred embodiment of the present invention, the reaction for preparing the denture soft lining silicone rubber is carried out at room temperature for 3 min to 5 min. For example, the reaction can be carried out at room temperature for 3 min, 4 min, 5 min, etc., but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0010] In a preferred embodiment of the present invention, the diisocyanate is one or more of hexamethylene diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, isophorone diisocyanate, 1,3-bis(1-isocyanato-1-methylethyl)benzene, m-phenylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, toluene diisocyanate, 1,3-phenylene diisocyanate, and diphenylmethane-4,4'-diisocyanate.

[0011] In a preferred embodiment of the present invention, the dithiol is one or more of 1,8-octanedithiol, 1,3-propanedithiol, 1,5-pentanedithiol, 1,9-nonanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,2-ethanedithiol, 1,4-butanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol, 1,10-decanedithiol, 1,4-benzenedimethanethiol, m-dibenzylthiol, 2,3-butanedithiol, 2,6-dimercaptopurine, 1,4-benzenedithiol, toluene-3,4-dithiol, dimercaptopropanol, 3,6-dioxa-1,8-octanedithiol, and 4,4'-thiobisbenzenethiol.

[0012] In a preferred embodiment of the present invention, the organic solvent is an ether organic solvent and / or an amide organic solvent.

[0013] The second object of the present invention is to provide a denture soft lining silicone rubber prepared by the above preparation method.

[0014] The third object of the present invention is to provide the application of the above denture soft lining silicone rubber in the preparation of the tissue surface of a denture, a denture soft lining and a denture stabilizing gasket.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention prepares a 3D printing high-strength and multi-property denture soft lining silicone rubber. During the preparation, a reaction product obtained by reacting a diisocyanate with an aminopropyl-terminated polydimethylsiloxane in a solvent is further reacted with a dithiol to obtain a denture soft lining silicone rubber containing dynamic thiourethane bonds and hydrogen bonds. The prepared denture soft lining silicone rubber can be dissolved and reshaped and hot-pressed and reshaped at high temperature. The reshaping, self-healing and degradation and recycling of the denture soft lining silicone rubber are realized by using the dynamic reversibility of the dynamic thiourethane bonds therein, and the melt extrusion type 3D printing of the denture soft lining silicone rubber is realized by using the actions of dynamic covalent bonds and hydrogen bonds, etc.

[0016] (2) By reacting a diisocyanate with an aminopropyl-terminated polydimethylsiloxane with a molar ratio of 1:0.2 to 0.4 at room temperature for 0.5 to 3 hours, and further reacting the product with a dithiol, the present invention obtains a high-strength denture soft lining silicone rubber with adjustable hardness and softness, reshaping ability, self-adhesion, degradability and recyclability, self-healing ability and printability. The preparation process of the synthesized 3D printing high-strength and multi-property denture soft lining silicone rubber is simple and fast, the atom utilization rate is 100%, no side reactions occur, and it is carried out at room temperature, which is energy-saving and environment-friendly.

[0017] (3) The mechanical properties of the denture soft lining silicone rubber synthesized by the present invention can be adjusted by adjusting the molar ratio of the dithiol and the aminopropyl-terminated polydimethylsiloxane after curing, mainly manifested as adjustable tensile strength, which can meet different clinical needs. As the proportion of the aminopropyl-terminated polydimethylsiloxane decreases and the proportion of the dithiol increases, the elastic modulus and tensile strength of the denture soft lining silicone rubber both increase, while the elongation at break decreases. It shows that the present invention can adjust the mechanical properties according to the use requirements.

[0018] (4) The denture soft lining silicone rubber synthesized by the present invention has extensive adhesion properties after curing and can achieve high-strength adhesion of various materials.

[0019] (5) The denture soft lining silicone rubber synthesized by the present invention has self-healing and welding functions after curing and can achieve crack healing and damage reshaping.

[0020] (6) The denture soft lining silicone rubber synthesized in the present invention can be printed with high precision by means of pellet feeding and screw printing, or can be shaped and adhesivelessly bonded to PMMA by hot pressing.

[0021] (7) Compared with the existing oral clinical soft lining silicone rubber that needs an adhesive to bond with the resin base, the denture soft lining silicone rubber prepared in the present invention has self-bonding performance and can obtain an effective bonding force with the resin base surface without introducing an adhesive layer.

[0022] (8) Compared with the existing oral clinical soft lining silicone rubber that needs to be ground and replaced when damaged, the denture soft lining silicone rubber of the present invention has crack self-healing performance, and the cracks can be healed by heating without replacement, thus prolonging the service life of the silicone rubber layer.

[0023] (9) Compared with the existing oral clinical soft lining silicone rubber that cannot change with the micro-deformation of the alveolar ridge in the patient's mouth and needs to be ground and replaced, the denture soft lining silicone rubber of the present invention has reshaping performance, and the tissue surface morphology of the silicone rubber can be reshaped by heating and pressing without replacement, thus prolonging the service life of the silicone rubber layer.

[0024] (10) Compared with the existing oral clinical soft lining silicone rubber that needs to be ground and replaced after aging and a part of the resin base is lost during the grinding process, the denture soft lining silicone rubber of the present invention can be debonded by heating, the replacement method is simple, the resin base is not damaged, the replacement process is simplified, and the service life of the denture can be effectively prolonged because the tissue surface of the denture base is not damaged, avoiding remaking the denture, reducing the number of patient visits, reducing the visit cost, and improving the comfort of treatment.

[0025] (11) Compared with the existing oral clinical soft lining silicone rubber that can only be added to the denture tissue surface by hand with an adhesive and the thickness of the soft lining silicone rubber cannot be accurately controlled, the denture soft lining silicone rubber of the present invention can be combined with the tissue surface of the resin base by 3D printing or preformed die casting, greatly improving the bonding accuracy with the tissue surface of the denture resin base. Combining its convenient preparation process flow and printable performance will greatly promote the changes in the mechanical manufacturing process and the performance of composite materials in related fields. Description of the Drawings

[0026] Figure 1 It is the performance diagram of the dumbbell-shaped specimens of the denture soft lining silicone rubber prepared in Examples 1 to 3 of the present invention, where a is the stress-strain curve diagram and b is the thermogravimetric curve diagram.

[0027] Figure 2 It is the photo of the reshaped specimen obtained after the denture soft lining silicone rubber prepared in Example 1 of the present invention is cryogenically pulverized and hot-pressed and reshaped.

[0028] Figure 3It is the stress-strain curve graph of the original sample prepared in Example 1 of the present invention and the sample after reshaping.

[0029] Figure 4 It is the test graph comparing the bonding strength of the denture soft lining silicone rubber bonded to different materials prepared in Example 1 of the present invention with that of the commercial glue.

[0030] Figure 5 It is the photo of the specimen of the denture soft lining silicone rubber prepared in Example 1 of the present invention before and after crack self-healing.

[0031] Figure 6 It is the test data graph of the single lap joint experiment of the bonding force between the denture soft lining silicone rubber prepared in Example 1, the clinically common soft lining silicone rubber and polymethyl methacrylate in oral clinic.

[0032] Figure 7 It is the 3D printed nasal model diagram of the denture soft lining silicone rubber prepared in Example 1 of the present invention.

[0033] Figure 8 It is the 3D printed hemisphere model diagram of the denture soft lining silicone rubber prepared in Example 1 of the present invention. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] A preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds includes the following steps: In an organic solvent, binary isocyanate and amino propyl terminated polydimethylsiloxane react to form isocyanate terminated polydimethylsiloxane, obtaining a reaction solution; Add binary thiol to the reaction solution, and isocyanate terminated polydimethylsiloxane reacts with binary thiol to form a dynamic thiocarbamate bond, preparing the denture soft lining silicone rubber.

[0036] The present invention uses the reaction of binary isocyanate (-NCO) with the mercapto group (-SH) of amino propyl terminated polydimethylsiloxane and binary thiol to form a denture soft lining silicone rubber containing dynamic thiocarbamate bonds.

[0037] The organic solvent is an ether organic solvent and / or an amide organic solvent; further, the ether organic solvent is tetrahydrofuran, and the amide organic solvent is N,N-dimethylformamide.

[0038] The molecular weight of the aminopropyl-terminated polydimethylsiloxane is 800 - 3000.

[0039] The denture soft lining silicone rubber prepared in the present invention contains dynamic covalent bonds, thioester bonds. The recycling and reshaping of the material are realized by the dynamic reversibility of the thioester bonds. The 3D printing is realized by the free radical polymerization of the double bonds in (meth)acrylate. The temperature-controlled bonding and debonding are realized by the hydrogen bonds of the material.

[0040] The denture soft lining silicone rubber prepared in the present invention can be used for the tissue surface of dentures, denture soft linings and denture stabilizing pads. The specific statements are as follows.

[0041] When used as a denture soft lining, first, clean and disinfect the tissue surface of the removable denture that needs soft lining for later use; under the conditions that satisfy the breaking, exchange and recombination of the dynamic covalent bonds required by the denture soft lining silicone rubber of the present invention and activate the fluidity and self-adhesion of the denture soft lining silicone rubber, according to the different oral conditions of the patient, cover 0.5 - 2 mm of the denture soft lining silicone rubber between the patient's oral model and the tissue surface of the removable denture, complete the thermocompression molding and self-bonding, modify and grind off the denture soft lining silicone rubber that exceeds the denture edge, and polish to complete the denture soft lining.

[0042] When used for tissue surface reshaping, due to the continuous absorption and remodeling of the patient's alveolar ridge, the tissue surface of the removable denture does not fit well with the patient's alveolar ridge after several years of use, resulting in poor retention, tenderness and other conditions, and the removable denture inevitably needs to be remade. However, the denture soft lining silicone rubber prepared in the present invention has the reshaping performance, that is, under the conditions that satisfy the breaking, exchange and recombination of its dynamic covalent bonds, the tissue surface can be reshaped according to the new shape after the absorption and remodeling of the patient's jaw bone, avoiding the remaking of the removable denture, and greatly reducing the patient's medical expenses and the number of medical visits. The specific operation method is to re-use impression materials or optical scanning to obtain the intraoral impression after absorption and remodeling and the impression of the opposing dentition with teeth, perform gypsum pouring or 3D printing of the digital model, place the original tissue surface of the removable denture under the conditions that satisfy the breaking, exchange and recombination of its dynamic covalent bonds, relocate it on the model after absorption and remodeling, perform centric occlusion and pressure on the opposing teeth, use the fluidity of the denture soft lining silicone rubber for tissue surface reshaping, and then cool and solidify to complete the tissue surface reshaping of the removable denture. For patients with obvious absorption of the jaw bone, a small amount of the denture soft lining silicone rubber of the present invention can be added on the original basis, place the original tissue surface of the removable denture under the conditions that satisfy the breaking, exchange and recombination of its dynamic covalent bonds, relocate it on the model after absorption and remodeling, perform centric occlusion and pressure on the opposing teeth, use the fluidity of the denture soft lining silicone rubber for tissue surface reshaping, and then cool and solidify to complete the tissue surface reshaping of the removable denture.

[0043] When the denture soft lining silicone rubber of the present invention needs to be replaced, the replacement process is very simple. Take the patient's oral model and print it or pour it with super hard gypsum for backup. Since the combination between the denture soft lining silicone rubber of the present invention and the base resin does not involve an adhesive layer, it is a glue-free self-adhesive. It only needs to be heated to the conditions required for the cleavage, exchange, and recombination of its covalent bonds, and it can be easily erased in its fluid state without adhesive residue. After removing the aged denture soft lining silicone rubber, immediately cover the denture tissue surface and the corresponding model with a new denture soft lining silicone rubber, and complete the hot pressing molding and self-adhesion under the condition of the centric occlusion with the opposing model, and modify and grind off the silicone rubber material exceeding the denture edge, and polish to complete the replacement of the denture soft lining.

[0044] The denture soft lining silicone rubber prepared by the present invention is used as a full denture stability gasket: Clinically, edentulous patients with poor alveolar ridge or oral mucosa conditions are prone to poor denture retention and tenderness when wearing full dentures, which affects the use and comfort. The denture soft lining silicone rubber of the present invention is made into an upper and lower full denture stability gasket with a thickness of 1 mm and lined on the denture tissue surface to improve stability and comfort. Specific usage method: After heating the stability gasket and the full denture in hot water according to the size of the denture tissue surface, place the stability gasket on the denture base tissue surface, press it tightly against the full denture tissue surface by hand, bite forcefully after putting on the denture, and then take out the denture and trim off the excess denture soft lining silicone rubber at the denture edge. The removal method is: spit it out after gargling, and gently shake the denture left and right by hand to remove it.

[0045] The aminopropyl-terminated polydimethylsiloxane used in the present invention is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a CAS number of 106214-84-0 and a commodity name of poly(dimethylsiloxane), bis(3-aminopropyl) terminated.

[0046] Example 1 This example provides a preparation method of denture soft lining silicone rubber. The binary thiol used in the raw materials is 3,6-dioxa-1,8-octanedithiol, the binary isocyanate is isophorone diisocyanate, and the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 1000. The specific preparation steps are as follows.

[0047] Add 4.44 g of isophorone diisocyanate and 14 g of aminopropyl-terminated polydimethylsiloxane to a flask equipped with a magnetic stirrer, react at room temperature for 30 minutes in 60 ml of tetrahydrofuran solvent. After the reaction is completed, directly add 1.1 g of 3,6-dioxa-1,8-octanedithiol, and stir for 3 min until the solution is uniform to obtain the denture soft lining silicone rubber, denoted as TC-PDMS 0.7 。

[0048] Example 2 This embodiment provides a preparation method of denture soft lining silicone rubber. The binary mercaptan used in the raw materials is 3,6-dioxa-1,8-octanedithiol, the binary isocyanate is isophorone diisocyanate, and the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 1000. The specific preparation steps are as follows.

[0049] Add 4.44 g of isophorone diisocyanate and 12 g of aminopropyl-terminated polydimethylsiloxane into a flask equipped with a magnetic stirrer, react at room temperature for 30 minutes in 60 ml of tetrahydrofuran solvent. After the reaction is completed, directly add 1.5 g of 3,6-dioxa-1,8-octanedithiol, stir for 3 min until the solution is homogeneous to obtain the denture soft lining silicone rubber, denoted as TC-PDMS 0.6 。

[0050] Example 3 This embodiment provides a preparation method of denture soft lining silicone rubber. The binary mercaptan used in the raw materials is 3,6-dioxa-1,8-octanedithiol, the binary isocyanate is isophorone diisocyanate, and the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 1000. The specific preparation steps are as follows.

[0051] Add 4.44 g of isophorone diisocyanate and 16 g of aminopropyl-terminated polydimethylsiloxane into a flask equipped with a magnetic stirrer, react at room temperature for 30 minutes in 60 ml of tetrahydrofuran solvent. After the reaction is completed, directly add 0.7 g of 3,6-dioxa-1,8-octanedithiol, stir for 3 min until the solution is homogeneous to obtain the denture soft lining silicone rubber, denoted as TC-PDMS 0.8 。

[0052] Example 4 This embodiment provides a preparation method of denture soft lining silicone rubber. The binary mercaptan used in the raw materials is 1,8-octanedithiol, the binary isocyanate is hexamethylene diisocyanate, and the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 3000. The specific preparation steps are as follows.

[0053] Add 3.4 g of hexamethylene diisocyanate and 42 g of aminopropyl-terminated polydimethylsiloxane into a flask equipped with a magnetic stirrer, react at room temperature for 1 h in 60 ml of tetrahydrofuran solvent. After the reaction is completed, directly add 1.1 g of 1,8-octanedithiol, stir for 5 min until the solution is homogeneous to obtain the denture soft lining silicone rubber.

[0054] Example 5 This embodiment provides a preparation method of denture soft lining silicone rubber. The binary mercaptan used in the raw materials is 1,3-propanedithiol, the binary isocyanate is toluene diisocyanate, and the molecular weight of the aminopropyl-terminated polydimethylsiloxane is 800. The specific preparation steps are as follows.

[0055] 0.6 g of toluene diisocyanate and 35 g of amino propyl terminated polydimethylsiloxane were added to a flask equipped with a magnetic stir bar, and reacted at room temperature for 3 h in 60 ml of tetrahydrofuran solvent. After the reaction, 3.5 g of 1,3-propanedithiol was directly added, and stirred for 4 min until the solution was uniform to obtain the silicone rubber for denture soft lining.

[0056] The mechanical properties of the silicone rubbers for denture soft lining prepared in Examples 1 to 3 were tested. As Figure 1 shown, the results of the universal tensile test showed that all specimens of the silicone rubber for denture soft lining (TC-PDMS) prepared in the present invention exhibited excellent mechanical properties.

[0057] During the synthesis process, by adjusting the molar ratio of the hard segment (3,6-dioxa-1,8-octanedithiol) and the soft segment (amino propyl terminated polydimethylsiloxane), its mechanical properties can be adjusted. As Figure 1 shown in b, from Example 1 to Example 3, as the proportion of the soft segment decreased and the proportion of the hard segment increased, both the elastic modulus and the tensile strength of TC-PDMS increased, while the elongation at break decreased. It shows that the present invention has adjustable mechanical properties. As Figure 1 shown in a, the silicone rubbers for denture soft lining prepared in Examples 1 to 3 began to decompose at 200 °C and the weight changed, indicating that they had excellent thermal stability.

[0058] The dumbbell-shaped mechanical specimens prepared in Example 1 were crushed and then hot-pressed at a pressure of 0.5 MPa and a temperature of 140 °C for 5 h to re-form dumbbell-shaped samples. See Figure 2 . As Figure 3 shown, since the dynamic thiourethane bonds therein can undergo reversible cleavage-recombination at high temperature, the cured crosslinked thermosetting material can also be reshaped and recycled.

[0059] The silicone rubber for denture soft lining prepared in Example 1 was made into a thin film and heated to 80 °C to bond different materials. As Figure 4 shown, stainless steel, glass, templates and ceramics were bonded. Compared with LOCTITE 3542, LOCTITE 425HS and 3M double-sided tape, the silicone rubber for denture soft lining prepared in Example 1 of the present invention had high bonding strength.

[0060] Arrow-shaped scratches were engraved on the surface of the silicone rubber for denture soft lining (TC-PDMS) prepared in Example 1 and heated to 120 °C. The scratches healed significantly, proving that this silicone rubber for denture soft lining had self-healing ability. See Figure 5 .

[0061] The single-lap experiment test of the bonding strength between the denture soft-lining silicone rubber prepared in Example 1 and polymethyl methacrylate in oral clinic was carried out, and the shear strength was measured to be 0.55 MPa. See Figure 6 . There is no significant difference in the bonding strength compared with the current bonding strength between elastomers and PMMA in clinic.

[0062] The denture soft-lining silicone rubber prepared in Example 1 was drawn into filaments, and then processed into pellets with a particle size less than 1 mm×1 mm×2 mm. The stl file of a hemisphere was designed, and a nasal model was further prepared by screw printing. From Figure 7 the results show that the denture soft-lining silicone rubber prepared by the present invention has good printing performance and excellent repeatability, and is expected to be used in digital precision machining.

[0063] The denture soft-lining silicone rubber prepared in Example 1 was drawn into filaments, and then processed into pellets with a particle size less than 1 mm×1 mm×2 mm. The stl file of the nasal shape was designed, and a hemisphere model was further prepared by screw printing. From Figure 8 the results show that the denture soft-lining silicone rubber prepared by the present invention has good printing performance and is expected to be used in digital precision machining of facial prostheses.

[0064] Based on the excellent mechanical properties and chemical stability of the thiourethane bond, the present invention also has stronger dynamic reversibility, remolding property, recycling performance and biological safety. Introducing the thiourethane dynamic covalent bond into the denture soft-lining silicone rubber can endow the denture soft-lining silicone rubber with properties such as remoldability and recyclability. In addition, the denture soft-lining silicone rubber prepared by the present invention also has adjustable mechanical properties and strong adhesion to general materials, and can be widely used in many fields such as medical materials, electronic assembly, automobiles, aerospace, wood processing and shoemaking.

[0065] The present invention relates to the comprehensive properties of denture soft-lining silicone rubber, especially the excellent mechanical properties and bonding properties can meet the on-demand debonding, and it is particularly suitable for the upgrading of oral denture soft-lining silicone rubber. While improving the performance of existing oral clinical soft-lining silicone rubber, new functional characteristics urgently needed clinically are added.

[0066] 1. Remolding property of denture soft-lining silicone rubber The denture soft-lining silicone rubber prepared by the present invention realizes self-repair and remolding through the dissociation of the dynamic covalent network during heating, and is obtained by the rapid recombination of the covalent network during cooling. It can be applied to patients with tenderness caused by the non-conformity between the tissue surface of the denture base and the alveolar mucosa due to alveolar ridge resorption. For such patients, it is often necessary to remanufacture the denture. By using the denture soft-lining silicone rubber of the present invention, the tissue surface of the denture can be remolded by heating to adapt to the changed alveolar mucosa morphology of the patient.

[0067] 0. Adhesive-free Self-adhesive Property of Denture Soft-lining Silicone Rubber Currently, all clinically used denture soft-lining silicone rubbers need to be bonded to the resin denture base through an adhesive. The bonding interface is weak, and the soft-lining silicone rubber is prone to peeling off, resulting in soft-lining failure. However, the denture soft-lining silicone rubber of the present invention has an adhesive-free chemical self-bonding with the denture resin base. The bonding force is reliable, and the bonding can be restored only by heating.

[0068] 1. Demountable Adhesive Property of Denture Soft-lining Silicone Rubber as Needed Although the denture soft-lining silicone rubber of the present invention has significant advantages in mechanical properties, due to the aging characteristics of the denture soft-lining silicone rubber, it is inevitably necessary to replace it regularly. Currently used clinically denture soft-lining silicone rubbers need to be connected to the resin denture base through an adhesive. The adhesive has permeability. When replacing the traditional soft-lining silicone rubber, not only the soft-lining silicone rubber material needs to be ground off, but also a layer of denture base resin needs to be ground off to eliminate the influence of the old adhesive. The repeated grinding and modification of the resin denture base not only greatly reduces the strength of the denture resin base, but also affects the accuracy of denture restoration. However, the denture soft-lining silicone rubber of the present invention can be easily demounted and replaced by heating in vitro. There is no adhesive at the bonding interface, and there is no need to adjust and grind the denture base.

[0069] In summary, the denture soft-lining silicone rubber of the present invention can effectively extend the service life of dentures, avoid remaking dentures, reduce the number of patient visits, lower the treatment cost, and improve the comfort of treatment. Combined with its convenient preparation process flow and printability, it will greatly promote the transformation of the mechanical manufacturing process and the properties of composite materials in related fields.

[0070] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0071] Obviously, those skilled in the art can make various changes and deformations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and deformations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these changes and deformations.

Claims

1. A preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds, characterized in that, It includes the following steps: In an organic solvent, a binary isocyanate and an aminopropyl-terminated polydimethylsiloxane react to form an isocyanate-terminated polydimethylsiloxane, obtaining a reaction solution; A binary thiol is added to the reaction solution, and the isocyanate-terminated polydimethylsiloxane reacts with the binary thiol to form a dynamic thiocarbamate bond, thereby preparing a denture soft lining silicone rubber.

2. The preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds according to claim 1, characterized in that The molar ratio of the binary isocyanate to the aminopropyl-terminated polydimethylsiloxane is 1:0.2 - 0.

4.

3. The preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds according to claim 1, characterized in that, The reaction for preparing the reaction solution is carried out at room temperature for 0.5 h - 3 h.

4. The preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds according to claim 1, characterized in that, The molar ratio of the binary isocyanate to the binary thiol is 1:0.6 - 0.

8.

5. The preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds according to claim 1, wherein The reaction for preparing the denture soft lining silicone rubber is carried out at room temperature for 3 min - 5 min.

6. The preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds according to claim 1, characterized in that, The binary isocyanate is one or more of hexamethylene diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, isophorone diisocyanate, 1,3-bis(1-isocyanato-1-methylethyl)benzene, m-xylene diisocyanate, 4,4'-methylenebis(phenyl isocyanate), p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, toluene diisocyanate, 1,3-phenylene diisocyanate, and diphenylmethane-4,4'-diisocyanate.

7. The preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds according to claim 1, characterized in that, The binary thiol is one or more of 1,8-octanedithiol, 1,3-propanedithiol, 1,5-pentanedithiol, 1,9-nonanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,2-ethanedithiol, 1,4-butanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol, 1,10-decanedithiol, 1,4-benzenedimethanethiol, m-dibenzylthiol, 2,3-butanedithiol, 2,6-dimercaptopurine, 1,4-benzenedithiol, toluene-3,4-dithiol, dimercaptopropanol, 3,6-dioxa-1,8-octanedithiol, and 4,4'-thiobisbenzenethiol.

8. The preparation method of a denture soft lining silicone rubber based on dynamic covalent bonds according to claim 1, characterized in that, The organic solvent is an ether-based organic solvent and / or an amide-based organic solvent.

9. A denture soft lining silicone rubber prepared by the preparation method according to any one of claims 1 - 8.

10. An application of the denture soft lining silicone rubber according to claim 9 in preparing the tissue surface of a denture, a denture soft lining, and a denture stabilizing gasket.

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