Aerosol, aerosol product as well as preparation method and application of aerosol product

Abstract

The invention provides an aerosol, an aerosol product as well as a preparation method and application of the aerosol product. The aerosol comprises glass ceramic powder, a monohydric alcohol solvent and a hydrofluorocarbon propellant, wherein in the Fourier transform infrared spectrum of the glass ceramic powder, the ratio of the hydroxyl characteristic peak area at the position of 3400-3500 cm <-1 > to the characteristic peak area of silicon-oxygen bond symmetrical stretching vibration at the position of 440-480 cm <-1 > is marked as ROH, and the ROH is 0.1-0.8. When the aerosol is used, the aerosol is sprayed on the inner surface of the zirconia false tooth, the monohydric alcohol solvent and the hydrofluorocarbon propellant are volatilized to form a glass ceramic powder layer, the glass ceramic powder layer is formed through sintering, and the bonding strength of zirconia and resin cement can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of dental materials technology, and in particular to an aerosol, an aerosol product, a method for preparing the aerosol, and its application. Background Technology

[0002] Zirconia ceramics, due to their superior mechanical strength and biocompatibility, have become a core material for dental restorations. With the development of high-transparency zirconia, its application has extended to anterior veneers. However, these restorations lack effective mechanical retention, and their long-term success rate relies almost entirely on chemical bonding. Zirconia surfaces are chemically inert and difficult to acid-etch, making them typically difficult-to-bond materials. Bonding failure leading to restoration detachment has become a major challenge and clinical risk in the application of aesthetic zirconia veneers.

[0003] To improve the bonding performance of zirconia, various surface treatment methods have been proposed in the existing technology. Sandblasting can increase surface roughness, but may introduce microcracks and impair the mechanical strength of the substrate; strong acid etching has poor controllability, easily damages the material's structure, and poses safety hazards; applying primers containing functional monomers (such as MDP) is the current mainstream solution, but its effect on improving bonding strength is limited and its long-term durability remains controversial.

[0004] In recent years, a method has emerged for sintering glass-ceramic layers on the inner surface of repair bodies. This method can form a highly active, etchable glass-ceramic layer on the surface of zirconia, thereby achieving strong and durable micromechanical bonding and chemical adhesion with resin.

[0005] CN114149256A discloses a glass-ceramic material for improving adhesion. Its core innovation lies in optimizing the formation of lithium disilicate crystals by introducing specific components such as GeO2 into the powder formulation, thereby improving the bonding strength with the zirconia matrix.

[0006] CN115724688A discloses a surface treatment agent that lowers the sintering temperature and improves the bonding strength by introducing components such as HfO2. These powders have proven effective when applied by conventional methods (such as preparing them into a paste for brushing), and after modification using this method, the bonding strength can reach 30 MPa.

[0007] However, existing technological achievements mostly focus on the development of the powder itself, lacking specific and feasible technical solutions for transforming it into a ready-to-use, clinically convenient, and long-term stable end product. Especially when preparing it as an aerosol, the conventional technique in this field is to add dispersants to maintain the stability of the powder in the liquid phase. However, as organic additives, dispersants decompose and carbonize during high-temperature sintering, remaining as impurities at the interface. More importantly, dispersant systems are prone to aging and failure during long-term storage, leading to powder caking and the formation of hard precipitates that cannot be recovered by shaking, causing the product to lose its function within its shelf life.

[0008] Therefore, developing a glass-ceramic powder aerosol product that does not rely on dispersants, is ready to use immediately, and can remain stable over a long period of time has become the key to promoting the large-scale clinical application of this advanced surface modification technology. Summary of the Invention

[0009] To solve the above-mentioned technical problems, the present invention provides an aerosol, an aerosol product, a preparation method thereof, and an application thereof, particularly a dispersant-free, self-stabilizing aerosol, an aerosol product, a preparation method thereof, and an application thereof, that is, a dispersant-free aerosol and aerosol product with recoverable sedimentation. Specifically, the present invention achieves this by adjusting the Fourier transform infrared spectrum of the glass-ceramic powder to be within the range of 3400~3500 cm⁻¹. -1 The area of ​​the characteristic hydroxyl peak at 440~480 cm⁻¹ is similar to that at 440~480 cm⁻¹. -1 The ratio of the characteristic peak area of ​​the symmetric stretching vibration of the silicon-oxygen bond is within a specific range, which enables the glass-ceramic powder to achieve long-term stability of the aerosol without dispersant. Furthermore, the glass-ceramic layer formed after use is firmly bonded to the zirconia substrate and has excellent adhesion performance.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides an aerosol comprising glass-ceramic powder, a monohydric alcohol solvent, and a hydrofluorocarbon propellant. The glass-ceramic powder exhibits a Fourier transform infrared spectrum within the range of 3400–3500 cm⁻¹. -1 The area of ​​the characteristic hydroxyl peak at 440~480 cm⁻¹ is similar to that at 440~480 cm⁻¹. -1 The ratio of the characteristic peak areas of the symmetric stretching vibration of the silicon-oxygen bond at a given point is denoted as R. OH The R OH The value is 0.1 to 0.8.

[0012] The aerosol provided by this invention has the following advantages:

[0013] First, this invention selects glass-ceramic powder with special Fourier transform infrared spectroscopy, which can effectively control the surface hydroxyl density of the glass-ceramic powder. This glass-ceramic powder can combine with monohydric alcohol solvents and hydrofluorocarbon propellants to form hydrogen bonds, thereby achieving long-term stability of the system without relying on dispersants and basically avoiding irreversible powder agglomeration.

[0014] Secondly, the present invention uses monohydric alcohol solvents, which not only have hydroxyl groups, thus enabling the formation of a solvation layer in the aerosol system, but also have the properties of easy evaporation without residue, thus having no negative impact on the surface of zirconia dentures.

[0015] Furthermore, this invention employs an aerosol form, which, by adding a hydrofluorocarbon propellant, can uniformly spray glass-ceramic powder onto the surface of zirconia dentures. During the spraying process, the glass-ceramic powder adheres tightly to the zirconia dentures under a certain spraying pressure. After sintering, a dense glass-ceramic coating can be formed on the surface of the zirconia dentures, resulting in excellent surface finishing effects.

[0016] Furthermore, the aerosol provided by this invention is a ready-to-use clinical end product, which solves the problems of cumbersome clinical operation and low standardization of existing powder technology.

[0017] It should be noted that the "self-stabilization" described in this invention refers to the long-term stability of the glass-ceramic powder in the aerosol product. Its core meaning is that, without the addition of organic dispersants, the glass-ceramic powder can resist irreversible agglomeration and caking in the monohydric alcohol solvent and hydrofluorocarbon propellant system for an extended period. Macroscopically, after static storage, although the glass-ceramic powder may settle, it can be easily and uniformly dispersed again with slight shaking, restoring a stable suspension suitable for spraying. This differs from the ideal emulsion state that seeks colloidal kinetic stability and achieves absolute zero sedimentation. This invention aims to ensure the functional reliability of the product throughout its entire shelf life, i.e., "sedimentation recoverability," rather than permanent homogeneous suspension.

[0018] Specifically, R OH It can be 0.1 to 0.8, for example, 0.1, 0.11, 0.12, 0.15, 0.2, 0.22, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7 or 0.8, etc.

[0019] It is worth noting that R in this invention OH The test can be performed using glass-ceramic powder added to the can, or using glass-ceramic powder collected from the can of the aerosol product.

[0020] Taking the collection of glass-ceramic powder from the can of an aerosol product as an example, the specific steps include:

[0021] In a well-ventilated environment, shake the can of the aerosol product thoroughly and spray its contents continuously and completely into a dry, clean glass petri dish or crucible until the solvent and hydrofluorocarbon propellant have completely evaporated, resulting in a powdery deposit.

[0022] The collected powdered sediment was transferred to a vacuum drying oven and dried at 60°C for 4 hours to thoroughly remove any trace amounts of residual solvent and moisture that may have been adsorbed on the powder surface.

[0023] The pre-dried powder is placed in a muffle furnace and calcined at 300°C for 15-30 minutes in air. This step aims to completely decompose and remove organic impurities such as organic indicators (colorants) added to the product without changing the hydroxyl density of the glass-ceramic powder itself, ensuring that the subsequent FTIR test results only reflect the surface chemical state of the powder itself.

[0024] Explanation of principle: This temperature range is much lower than the lower limit temperature for powder pretreatment (adjusting hydroxyl density). Under these conditions, organic pigments can be effectively decomposed and oxidized, while the hydroxyl density on the powder surface will not change significantly due to brief low-temperature burning.

[0025] Take 1.0 mg of the glass ceramic powder treated as described above, mix it thoroughly with 200 mg of dry potassium bromide (KBr) powder in an agate mortar and grind it evenly. Then, use a tablet press to press it into transparent sheets under a pressure of 10 MPa.

[0026] The prepared KBr pellet was placed in the sample chamber of an FTIR spectrometer and heated at 4000–4000 cm⁻¹. -1 Scanning was performed within the wavenumber range. A comparison was made between 3400 and 3500 cm⁻¹. -1 The characteristic peak area of ​​the (OH stretching vibration) is 440~480 cm⁻¹ -1 The characteristic peak area at (Si-O symmetric stretching vibration) is calculated, and the ratio of the two (R) is calculated. OH This serves as a semi-quantitative indicator of surface hydroxyl density.

[0027] Preferably, the aerosol comprises, by weight percentage: 5-30 wt% glass-ceramic powder; 5-45 wt% monohydric alcohol solvent; and 25-90 wt% hydrofluorocarbon propellant.

[0028] Specifically, 5 to 30 wt% of glass-ceramic powder, for example, can be 5 wt%, 8 wt%, 11 wt%, 14 wt%, 17 wt%, 19 wt%, 22 wt%, 25 wt%, 28 wt%, or 30 wt%, but is not limited to the listed values. Other unlisted values ​​within this range also apply.

[0029] Monohydric alcohol solvents of 5 to 45 wt%, such as 5 wt%, 10 wt%, 14 wt%, 19 wt%, 23 wt%, 28 wt%, 32 wt%, 37 wt%, 41 wt%, or 45 wt%, etc., but not limited to the listed values, and other unlisted values ​​within this range also apply.

[0030] Hydrofluorocarbon propellants of 25 to 90 wt%, such as 25 wt%, 33 wt%, 40 wt%, 47 wt%, 54 wt%, 62 wt%, 69 wt%, 76 wt%, 83 wt%, or 90 wt%, etc., but not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0031] Preferably, the monohydric alcohol solvent has 2 to 4 carbon atoms, for example, 2, 3 or 4.

[0032] Preferably, the monohydric alcohol solvent includes any one or a combination of at least two of ethanol, isopropanol, n-propanol, isobutanol, sec-butanol, or n-butanol, wherein typical but non-limiting combinations are combinations of ethanol and isopropanol, n-propanol and isopropanol, ethanol and n-propanol, isobutanol and isopropanol, and ethanol and sec-butanol.

[0033] Preferably, the hydrofluorocarbon propellant comprises hydrofluoroolefins and / or hydrofluoroalkanes.

[0034] Preferably, the hydrofluorocarbon propellant comprises any one or a combination of at least two of tetrafluoroethane, tetrafluoropropylene, heptafluoropropane, or difluoroethane, wherein typical but non-limiting combinations are combinations of tetrafluoroethane and tetrafluoropropylene, heptafluoropropane and tetrafluoropropylene, tetrafluoroethane and heptafluoropropane, difluoroethane and tetrafluoropropylene, and tetrafluoroethane and difluoroethane.

[0035] This invention does not strictly limit the specific chemical composition of the glass-ceramic powder; its core requirement is that the glass-ceramic powder can be tuned to R. OH The value is between 0.1 and 0.8. Any glass-ceramic composition capable of forming a glass-ceramic layer on the surface of zirconia by sintering is applicable, and its specific components can be a variety of choices known in the art.

[0036] Preferably, based on the mass of the glass-ceramic powder as 100%, the composition of the glass-ceramic powder includes SiO2: 55~85wt%; Li2O: 8~20wt%.

[0037] Specifically, the composition of the glass ceramic powder includes SiO2: 55~85wt%, for example, it can be 55wt%, 59wt%, 62wt%, 65wt%, 69wt%, 72wt%, 75wt%, 79wt%, 82wt%, or 85wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable; Li2O: 8~20wt%, for example, it can be 8wt%, 10wt%, 11wt%, 12wt%, 14wt%, 15wt%, 16wt%, 18wt%, 19wt%, or 20wt%, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0038] Preferably, the glass-ceramic powder further includes a nucleating agent and / or additives.

[0039] The glass powder in this invention may optionally include any one or a combination of at least two of the following components: P2O5, ZrO2, Al2O3, B2O3, Na2O, K2O, CaO, MgO, or ZnO. To further adjust performance, such as lowering the sintering temperature, improving the matching of thermal expansion coefficients, or increasing bonding strength, its composition may also include any one or a combination of at least two of the following oxides: GeO2, HfO2, Nb2O5, or Y2O3.

[0040] It is particularly noteworthy that some existing patents have disclosed glass-ceramic powder compositions suitable for this purpose, and these known powders can be used as alternative embodiments of the present invention. For example:

[0041] The composition disclosed in patent CN114149256B; the composition disclosed in patent CN115724688A.

[0042] Preferably, the particle size range of the glass ceramic powder is 0.3~60μm. For example, the particle size can be 0.3μm, 7μm, 13μm, 20μm, 26μm, 33μm, 40μm, 46μm, 53μm or 60μm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the particle size D50 of the glass ceramic powder is 1~30μm, for example, it can be 1μm, 5μm, 8μm, 11μm, 14μm, 18μm, 21μm, 24μm, 27μm or 30μm, etc., but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0044] In a second aspect, the present invention provides an aerosol product, the aerosol product comprising a can, a valve, and the aerosol described in the first aspect encapsulated within the can.

[0045] The present invention does not impose any special limitations on the specific can body or valve structure of the aerosol product, and aerosol cans and valves known to those skilled in the art can be used.

[0046] The aerosol product provided by the present invention also includes conduits and actuators commonly found in aerosol products, the actuators including nozzles, etc.

[0047] As an example, the aerosol product includes a can, a valve, a conduit, and an actuator; the can is internally an aerosol chamber, which is filled with aerosol; the valve is located on the upper part of the can and is movable up and down along the axial direction of the can; the actuator is located on the upper part of the valve and includes a pressing part and a nozzle; the pressing part is coaxially arranged with the valve, and the nozzle is located on one side of the pressing part; the conduit is located inside the aerosol chamber and is connected to the nozzle.

[0048] When the pressing part is pressed to move the valve downward along the axial direction of the can, the aerosol in the aerosol chamber is sprayed out from the nozzle in the form of aerosol through the conduit; when the pressure of the pressing part is released to move the valve along the axial direction of the can, the upper part of the can is blocked by the valve, and the can is in a sealed state.

[0049] Thirdly, the present invention provides a method for preparing the aerosol product described in the first aspect or the aerosol product described in the second aspect, the method comprising:

[0050] (1) The glass ceramic powder raw material is calcined to reduce the R of the glass ceramic powder. OH The concentration is 0.1~0.8, and the processed glass-ceramic powder is obtained.

[0051] (2) Mix the treated glass ceramic powder described in step (1) with a monohydric alcohol solvent to make a slurry.

[0052] (3) Fill the slurry described in step (2) into the tank and seal it.

[0053] (4) Press hydrofluorocarbon propellant into the sealed tank after step (3).

[0054] The preparation method provided by the present invention adjusts the surface hydroxyl density of glass ceramic powder raw materials by calcining them, thereby achieving self-stabilization of aerosols without dispersants.

[0055] The preparation method provided by this invention is simple and easy to implement, and is easy to industrialize, with broad application prospects.

[0056] Preferably, the calcination temperature in step (1) is 400~600℃, for example, it can be 400℃, 423℃, 445℃, 467℃, 489℃, 512℃, 534℃, 556℃, 578℃ or 600℃, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0057] The present invention preferably controls the calcination temperature within the above-mentioned range. Within this temperature range, the hydroxyl groups on the surface of the glass ceramic powder can be effectively removed by dehydration condensation. Moreover, within this temperature range, the effect on the properties of the glass ceramic powder itself, such as particle size, chemical stability, or phase structure, is relatively small.

[0058] Preferably, the calcination time is 1 to 4 hours, for example, it can be 1 hour, 1.4 hours, 1.7 hours, 2 hours, 2.4 hours, 2.7 hours, 3 hours, 3.4 hours, 3.7 hours or 4 hours, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0059] Preferably, the particle size of the glass ceramic powder raw material is 0.3~60μm. For example, the particle size can be 0.3μm, 7μm, 13μm, 20μm, 26μm, 33μm, 40μm, 46μm, 53μm or 60μm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0060] Preferably, the particle size D50 of the glass ceramic powder raw material is 1~30μm, for example, it can be 1μm, 5μm, 8μm, 11μm, 14μm, 18μm, 21μm, 24μm, 27μm or 30μm, etc., but is not limited to the listed values, and other unlisted values ​​in this range are also applicable.

[0061] Preferably, the pressure inside the tank after the hydrofluorocarbon propellant is injected is 0.2~0.9 MPa, for example, it can be 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa, 0.6 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa or 0.9 MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0062] Fourthly, the present invention provides an application of the aerosol product described in the first aspect and / or the aerosol product described in the second aspect, wherein the aerosol is used to treat the surface of zirconium oxide.

[0063] Preferably, the zirconium oxide is a zirconium oxide denture.

[0064] Preferably, the application includes:

[0065] (1) The aerosol is sprayed onto the bonding surface of the zirconia denture to obtain the treated denture.

[0066] (2) The surface of the denture after the treatment in step (1) is sintered to form a glass-ceramic layer on the surface of the zirconia denture.

[0067] Preferably, the sintering temperature is 800~950℃.

[0068] Preferably, the sintering time is 10-40 minutes.

[0069] Preferably, the bonding strength between the glass-ceramic layer and the resin cement is 18MPa to 45MPa, for example, it can be 18MPa, 21MPa, 24MPa, 27MPa, 30MPa, 33MPa, 36MPa, 39MPa, 42MPa or 45MPa, but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0070] Compared with the prior art, the present invention has at least the following beneficial effects:

[0071] (1) The aerosol provided by the present invention regulates the surface properties of glass ceramic powder, namely, adjusts the hydroxyl density, and utilizes the synergistic hydrogen bonding effect between monohydric alcohol solvent and hydrofluorocarbon propellant, thereby eliminating the need for dispersants and eliminating the potential hazards of dispersants.

[0072] (2) The self-stabilizing system in the aerosol product provided by the present invention does not rely on chemical dispersants that are prone to aging and failure. Therefore, the aerosol product can effectively resist caking during its shelf life and ensure the reliability of the product throughout its entire life cycle. Generally speaking, it can remain stable within three years.

[0073] (3) The aerosol product provided by the present invention makes the coating process fast and uniform through the form of aerosol, which simplifies the clinical operation process and improves the standardization level and efficiency of restoration processing; moreover, the glass ceramic layer formed by sintering is pure and dense, and forms a strong bond with the zirconium oxide substrate, thereby providing the denture with extremely high and durable resin bonding strength. Attached Figure Description

[0074] Figure 1 This is a schematic diagram of the structure of the aerosol product provided by the present invention.

[0075] Figure 2 This is a comparison chart of the Fourier transform infrared (FTIR) spectra of the glass-ceramic powder described in Example 1 and Comparative Example 1 of the present invention.

[0076] Figure 3 This is a comparison diagram of the states of Example 1 and Comparative Example 3 after the accelerated stability test.

[0077] Figure 4 This is a backscattered electron image of the interface between the glass-ceramic layer and the zirconium oxide substrate described in Example 1.

[0078] In the diagram: 1. Tank; 2. Valve; 3. Actuator; 4. Aerosol; 5. Conduit. Detailed Implementation

[0079] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0080] It should be understood that in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0081] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0082] For ease of experimentation and comparison, the following aerosol products all adopt the following structure, specifically, as follows: Figure 1 As shown, the aerosol 4 product includes a canister 1, a valve 2, a conduit 5, and an actuator 3. The canister 1 contains an aerosol 4 chamber, which is filled with aerosol 4. The valve 2 is located on the upper part of the canister 1 and can move up and down along the axial direction of the canister 1. The actuator 3 is located on the upper part of the valve 2 and includes a pressing part and a nozzle. The pressing part is coaxially arranged with the valve 2, and the nozzle is located on one side of the pressing part. The conduit 5 is located in the aerosol chamber and is connected to the nozzle.

[0083] When the pressing part is pressed to move the valve 2 downward along the axial direction of the can body 1, the aerosol 4 in the aerosol 4 chamber is sprayed out from the nozzle in the form of aerosol through the conduit 5; when the pressure of the pressing part is released to move the valve 2 along the axial direction of the can body 1, the upper part of the can body 1 is blocked by the valve 2, and the can body 1 is in a sealed state.

[0084] Example 1

[0085] This embodiment provides an aerosol comprising 12.7 wt% glass-ceramic powder (particle size D50 of 7.068 μm); 39.7 wt% monohydric alcohol solvent (ethanol and isopropanol in a weight ratio of 1:1); and 47.6 wt% hydrofluorocarbon propellant (tetrafluoroethane (HFA-134a)).

[0086] This embodiment also provides a method for preparing the aerosol product formed by the above-mentioned aerosol, the preparation method comprising the following steps:

[0087] (1) The glass ceramic powder raw material (the formula disclosed in Example 1 of CN114149256B, with a particle size D50 of 7.032 μm) was placed in a muffle furnace and calcined at 500°C for 2 h to obtain the treated glass ceramic powder;

[0088] (2) Mix the treated glass-ceramic powder described in step (1) with a monohydric alcohol solvent to prepare a slurry;

[0089] (3) Fill the tank with the slurry described in step (2) and seal it;

[0090] (4) Press hydrofluorocarbon propellant into the sealed tank after step (3), with a pressure of 0.51 MPa in the tank.

[0091] Example 2

[0092] This embodiment provides an aerosol, which differs from that in Example 1 in that the glass ceramic powder is composed according to the formula disclosed in Example 1 of CN115724688A, all monohydric alcohol solvents are ethanol, and the calcination temperature of the glass ceramic powder raw material in the preparation method is 480℃. All other aspects are the same as in Example 1.

[0093] Example 3

[0094] This embodiment provides an aerosol, which differs from that in Example 1 in that the monohydric alcohol solvent is entirely n-propanol, and the calcination temperature of the glass ceramic powder raw material in the preparation method is 450°C, while the rest are the same as in Example 1.

[0095] Example 4

[0096] This embodiment provides an aerosol, which differs from that in Example 1 in that the monohydric alcohol solvent is entirely isobutanol, and the calcination temperature of the glass ceramic powder raw material in the preparation method is 400℃. All other aspects are the same as in Example 1.

[0097] Example 5

[0098] This embodiment provides an aerosol, which differs from that in Example 1 in that the hydrofluorocarbon propellant is replaced with tetrafluoropropylene (HFO-1234ze), and the calcination temperature of the glass ceramic powder raw material in the preparation method is 600℃, while the rest are the same as in Example 1.

[0099] Example 6

[0100] This embodiment provides an aerosol, which differs from that of Example 1 in that, based on Example 1, an additional 0.048 wt% of hydrophilic fumed silica (Aerosil 200) is added as a dispersant, consisting of glass ceramic powder, monohydric alcohol solvent, and hydrofluorocarbon propellant. All other aspects are the same as in Example 1.

[0101] This embodiment also provides a method for preparing the aerosol product formed by the above-mentioned aerosol, the preparation method comprising the following steps:

[0102] (1) The glass ceramic powder raw material (the formula disclosed in Example 1 of CN114149256B, with a particle size D50 of 7.032 μm) was placed in a muffle furnace and calcined at 500°C for 2 h to obtain the treated glass ceramic powder;

[0103] (2) Add fumed silica to a monohydric alcohol solvent and disperse it by high-speed shearing at 700 r / min for 25 min to form a uniform dispersion; then add the glass ceramic powder treated in step (1) to the dispersion to make a slurry;

[0104] (3) Fill the tank with the slurry described in step (2) and seal it;

[0105] (4) Press hydrofluorocarbon propellant into the sealed tank after step (3), with a pressure of 0.54 MPa in the tank.

[0106] Example 7

[0107] This embodiment provides an aerosol comprising 30 wt% glass-ceramic powder (particle size D50 of 7.054 μm); 45 wt% monohydric alcohol solvent (isobutanol and sec-butanol in a weight ratio of 1:1); and 25 wt% hydrofluorocarbon propellant (heptafluoropropane).

[0108] This embodiment also provides a method for preparing the aerosol product formed by the above-mentioned aerosol, the preparation method comprising the following steps:

[0109] (1) The glass ceramic powder raw material (the formula disclosed in Example 1 of CN114149256B, with a particle size of 7.032 μm) was placed in a muffle furnace and calcined at 400°C for 4 hours to obtain the treated glass ceramic powder;

[0110] (2) Mix the treated glass-ceramic powder described in step (1) with a monohydric alcohol solvent to prepare a slurry;

[0111] (3) Fill the tank with the slurry described in step (2) and seal it;

[0112] (4) Press hydrofluorocarbon propellant into the sealed tank after step (3), with a pressure of 0.52 MPa in the tank.

[0113] Example 8

[0114] This embodiment provides an aerosol comprising 5 wt% glass-ceramic powder (particle size 8.593 μm); 5 wt% monohydric alcohol solvent (n-propanol); and 90 wt% hydrofluorocarbon propellant (difluoroethane).

[0115] This embodiment also provides a method for preparing the aerosol product formed by the above-mentioned aerosol, the preparation method comprising the following steps:

[0116] (1) The glass ceramic powder raw material (the formula disclosed in Example 1 of CN115724688A, with a particle size D50 of 8.524μm) was placed in a muffle furnace and calcined at 600℃ for 1h to obtain the treated glass ceramic powder;

[0117] (2) Mix the treated glass-ceramic powder described in step (1) with a monohydric alcohol solvent to prepare a slurry;

[0118] (3) Fill the tank with the slurry described in step (2) and seal it;

[0119] (4) Press hydrofluorocarbon propellant into the sealed tank after step (3), with a pressure of 0.41 MPa in the tank.

[0120] Example 9

[0121] This embodiment provides an aerosol, the preparation process of which is the same as that of Example 1, except that the aerosol includes 20 wt% glass ceramic powder; 10 wt% monohydric alcohol solvent; and 70 wt% hydrofluorocarbon propellant.

[0122] Example 10

[0123] This embodiment provides an aerosol, the preparation process of which is the same as that of Example 1, except that the aerosol includes 10 wt% glass ceramic powder; 25 wt% monohydric alcohol solvent; and 65 wt% hydrofluorocarbon propellant.

[0124] Comparative Example 1

[0125] This comparative example provides an aerosol, which differs from Example 1 in that the calcination treatment in step (1) is not performed in the preparation method.

[0126] Comparative Example 2

[0127] This comparative example provides an aerosol that differs from Example 1 in that all monohydric alcohol solvents are replaced with acetone.

[0128] Comparative Example 3

[0129] This comparative example provides an aerosol that differs from Example 1 in that all monohydric alcohol solvents are replaced with water.

[0130] Comparative Example 4

[0131] This comparative example provides an aerosol that differs from Example 1 in that all monohydric alcohol solvents are replaced with propylene glycol.

[0132] Comparative Example 5

[0133] This comparative example provides an aerosol that differs from Example 1 in that all monohydric alcohol solvents are replaced with n-hexane.

[0134] Comparative Example 6

[0135] This comparative example provides an aerosol, which differs from Example 1 in that the calcination temperature in step (1) of the preparation method is replaced with 650°C.

[0136] Comparative Example 7

[0137] This comparative example provides an aerosol, which differs from Example 1 in that the calcination temperature in step (1) of the preparation method is replaced with 350°C.

[0138] Comparative Example 8

[0139] This comparative example provides an aerosol, which differs from Example 1 in that the calcination time in step (1) of the preparation method is 0.5 h.

[0140] Comparative Example 9

[0141] This comparative example provides an aerosol, which differs from Example 1 in that the calcination treatment time in step (1) of the preparation method is 5 hours.

[0142] Comparative Example 10

[0143] This comparative example provides an aerosol, which differs from Example 1 in that the hydrofluorocarbon propellant is replaced with an equal amount of liquefied petroleum gas (LPG, with a propane content of 50 wt% and a butane content of 50 wt%).

[0144] Comparative Example 11

[0145] This comparative example provides an aerosol that differs from Example 1 in that the hydrofluorocarbon propellant is replaced with an equal amount of dimethyl ether (DME).

[0146] Comparative Example 12

[0147] This comparative example provides an aerosol, which differs from Example 6 in that the calcination treatment in step (1) is not performed in the preparation method.

[0148] Test method:

[0149] (1) R OH Detection of R in this invention: OH The test can be performed using glass-ceramic powder added to the can, or using glass-ceramic powder collected from the can of the aerosol product.

[0150] The following experimental data are from the testing of glass-ceramic powder collected from the can of the aerosol product. The specific steps include:

[0151] In a well-ventilated environment, shake the can of the aerosol product thoroughly and spray its contents continuously and completely into a dry, clean glass petri dish or crucible until the solvent and hydrofluorocarbon propellant have completely evaporated, resulting in a powdery deposit.

[0152] The collected powdered sediment was transferred to a vacuum drying oven and dried at 60°C for 4 hours to thoroughly remove any trace amounts of residual solvent and moisture that may have been adsorbed on the powder surface.

[0153] The pre-dried powder is placed in a muffle furnace and calcined at 300°C for 20 minutes in air. This step aims to completely decompose and remove organic impurities such as organic indicators (colorants) added to the product without changing the hydroxyl density of the glass-ceramic powder body surface, ensuring that the subsequent FTIR test results only reflect the surface chemical state of the powder itself.

[0154] Explanation of principle: This temperature range is much lower than the lower limit temperature for powder pretreatment (adjusting hydroxyl density). Under these conditions, organic pigments can be effectively decomposed and oxidized, while the hydroxyl density on the powder surface will not change significantly due to brief low-temperature burning.

[0155] Take about 1.0 mg of the glass ceramic powder treated as described above, mix it thoroughly with about 200 mg of dry potassium bromide (KBr) powder in an agate mortar and grind it evenly. Then use a tablet press to press it into transparent sheets under a pressure of 10 MPa.

[0156] The prepared KBr pellet was placed in the sample chamber of an FTIR spectrometer and heated at 4000–4000 cm⁻¹. -1 Scanning was performed within the wavenumber range. A comparison was made between 3400 and 3500 cm⁻¹. -1 The characteristic peak area of ​​the (OH stretching vibration) is 440~480 cm⁻¹ -1 The characteristic peak area at (Si-O symmetric stretching vibration) is calculated, and the ratio of the two (R) is calculated. OH This serves as a semi-quantitative indicator of surface hydroxyl density.

[0157] (2) Accelerated stability test: The packaged aerosol product was placed in a constant temperature oven at 50°C and stored for 30 days. After the test, the sedimentation was visually inspected and the ease and uniformity of redispersibility were evaluated by manually shaking the product 10 times.

[0158] (3) Adhesion strength test: Each aerosol product is evenly sprayed onto the surface of the zirconia ceramic column (φ10mm×8mm), and calcined according to the product instructions to form a glass ceramic layer.

[0159] The glass-ceramic layer was etched with a 4.5% acid etchant for 90 seconds, cleaned, and dried. It was then bonded to resin cement using an adhesive to form a shear specimen. After light curing, the specimen was immersed in distilled water at 37°C for 24 hours.

[0160] Shear strength tests were performed using a universal testing machine at a crosshead speed of 0.75 mm / min until specimen failure. The maximum load was recorded, and the shear bond strength (MPa) was calculated based on the bond area. Each test group contained at least 10 valid specimens, and the results are expressed as an average. This test method conforms to the industry standard YY / T0518-2009.

[0161] The Fourier transform infrared (FTIR) spectra of the glass-ceramic powders described in Example 1 and Comparative Example 1 are shown in the figure below. Figure 2 As shown, from Figure 2 It can be seen that the surface hydroxyl density of the glass-ceramic powder in Example 1 is significantly reduced.

[0162] The comparison diagram of the states of Example 1 and Comparative Example 3 after the accelerated stability test is shown in the figure below. Figure 3 As shown, from Figure 3 It can be seen that after the accelerated stability test, Example 1 was still able to disperse stably, while Comparative Example 3 showed obvious sedimentation and stratification. The aerosol system provided by Example 1 is more stable than Comparative Example 3.

[0163] Figure 4 This is a backscattered electron image of the interface between the glass-ceramic layer and the zirconia substrate described in Example 1. The image shows that the glass-ceramic layer and the zirconia substrate are tightly bonded together, and there are almost no defects at the interface.

[0164] The test results of the above embodiments and comparative examples are shown in Table 1.

[0165] Table 1

[0166]

[0167] The following points can be observed from Table 1:

[0168] (1) Examples 1 to 10 of the present invention all exhibit excellent immediate dispersibility, and after accelerated aging, they can still be restored to a uniformly dispersed suspension state after shaking. This proves that the aerosol provided by the present invention has reliable performance throughout the entire product life cycle.

[0169] (2) Example 6 was based on Example 1 (without dispersant) with the addition of fumed silica. Test results showed that the system could still be redispersed after accelerated stability testing, but its long-term stability was slightly lower than that of the preferred dispersant-free scheme of the present invention. This is because when an exogenous dispersant is introduced into a self-stabilizing system, the latter competes with solvent molecules for active sites on the powder surface, resulting in an acceptable, non-deteriorating slight decrease in the long-term stability of the system compared to the preferred dispersant-free scheme. However, even in such cases, the hydrogen bond network formed by the powder and solvent remains the dominant and core mechanism for maintaining the stability of the system. The addition of an exogenous dispersant did not change this fundamental fact, indicating that the aerosol provided by the present invention is compatible with schemes that include dispersants.

[0170] (3) R OH Impact

[0171] A comparison between Comparative Example 1 and Example 1 shows that the R of the glass-ceramic powder in Example 1 is higher. OH The value is 0.45, while the R of the glass-ceramic powder in Comparative Example 1 is... OH The result is 1.0, indicating that the glass-ceramic powder in Comparative Example 1 formed agglomerates after storage in the solvent system of this invention, while that in Example 1, only slight sedimentation occurred under the same storage conditions, and it could be redispersed by shaking. This shows that the surface hydroxyl characteristic peak intensity of the glass-ceramic powder in Comparative Example 1 is relatively large. Under these conditions, the powder particles tend to form hydrogen bonds with each other through excessive surface hydroxyl groups in the solvent, leading to interparticle bridging and agglomeration, which macroscopically manifests as agglomeration after storage and difficulty in redispersing. After calcination treatment, the surface hydroxyl density of the powder in Example 1 decreased, and R... OHWhen the concentration is reduced to 0.45, the hydrogen bonding between powder particles is weakened, thereby inhibiting particle agglomeration. Simultaneously, the powder surface retains an appropriate amount of hydroxyl groups, enabling it to effectively interact with monohydric alcohol solvents and hydrofluorocarbon propellant molecules to form a stable solvation layer. Macroscopically, this results in only slight sedimentation after accelerated testing, easy redispersibility upon shaking, and a high adhesion strength of 32.5 MPa.

[0172] In Comparative Examples 6 and 9, the excessive calcination intensity led to the excessive removal of hydroxyl groups from the powder surface, resulting in an insufficient R... OH A value below 0.1 indicates a significantly reduced number of hydrogen bonding sites between powder particles and alcohol solvent molecules, preventing the formation of a complete and robust solvation layer. This leads to decreased system stability, with particles settling and agglomerating due to gravity and van der Waals forces, resulting in poor redispersibility.

[0173] Both Comparative Examples 7 and 8 suffered from insufficient removal of hydroxyl groups on the powder surface due to inadequate calcination treatment intensity, resulting in insufficient R... OH The values ​​are all higher than 0.8. Excessively high hydroxyl density causes powder particles to strongly tend to bridge each other through intermolecular hydrogen bonds during storage, forming hard, dense agglomerates. The binding energy provided by these agglomerates exceeds the mechanical energy provided by shaking, leading to redispersibility failure, macroscopically manifested as bridging that cannot be dispersed by shaking.

[0174] The above comparative examples show that the present invention increases the surface hydroxyl density (R) of glass-ceramic powder. OH The value should be controlled within a specific range of 0.1 to 0.8. Deviations from this range, whether too high or too low, will impair the redispersibility of the system, making it difficult to store the product stably without a dispersant.

[0175] (4) Effect of solvent

[0176] The results of the embodiments and comparative examples of the present invention show that the choice of solvent is one of the decisive factors in achieving dispersant-free self-stabilization.

[0177] Examples 1-4 show that when ethanol, isopropanol, n-propanol, and isobutanol are used as solvents, the system can form an initial suspension and remain redispersible after accelerated experiments.

[0178] Comparative Example 2 (acetone) initially dispersed well, but became difficult to disperse after storage. Comparative Example 3 (water) caused the powder to form hard precipitates and clump together.

[0179] Comparative Example 4 (propylene glycol) failed due to excessive viscosity. Comparative Example 5 (n-hexane) resulted in phase separation because it could not wet the powder.

[0180] The results show that only C2-C4 monohydric alcohols can achieve a balance between dispersion, storage stability, and process feasibility in the aerosol system provided by this invention.

[0181] A. Hydrogen bond donor and acceptor capabilities and moderate hydrogen bond strength

[0182] The failure of Comparative Example 5 (n-hexane) proves that the lack of hydrogen bonding makes it impossible to wet and disperse the powder.

[0183] Comparative Example 2 (acetone) provides crucial evidence: acetone, as a hydrogen bond acceptor, can effectively anchor to hydroxyl groups on the powder surface through its carbonyl oxygen atom, thus achieving good initial dispersion. However, its molecular structure prevents it from acting as a hydrogen bond donor. This critical deficiency prevents the formation of a dynamic, interwoven three-dimensional hydrogen bond network between acetone molecules, glass powder, and the hydrofluorocarbon propellant. This network is essential for long-term resistance to particle sedimentation and aggregation. Therefore, the irreversible aggregation of the acetone-solvent system after storage demonstrates that hydrogen bond anchoring alone is insufficient to maintain long-term stability.

[0184] The failure of Comparative Example 3 (water) proves that excessively strong hydrogen bonding can lead to the formation of strong "water bridges" between powder particles, causing rapid flocculation and caking.

[0185] B. Suitable volatility

[0186] Comparative Example 2 (acetone) has a low boiling point (56℃) and evaporates too quickly, resulting in the accumulation of dry powder in the coating after spraying, which prevents it from leveling.

[0187] Comparative Example 4 (propylene glycol) has an excessively high boiling point (188℃), making it difficult to volatilize and resulting in severe sagging after spraying.

[0188] C. Lower viscosity

[0189] Comparative Example 4 (propylene glycol) has a high viscosity (~56 mPa·s) and poor spray atomization effect.

[0190] C2-C4 monohydric alcohols have low viscosity (e.g., ethanol: ~1.2 mPa·s), ensuring good flowability and atomization properties of the slurry, enabling the formation of a uniform coating.

[0191] This invention discovers that C2-C4 monohydric alcohols can simultaneously satisfy all the above conditions. Among them, C2-C4 monohydric alcohols (ethanol, isopropanol, n-propanol, n-butanol) can improve the stability and performance of aerosols due to their optimal balance in safety and overall performance.

[0192] (5) Effects of hydrofluorocarbon propellants

[0193] In this invention, hydrofluorocarbon propellants are not only the medium that provides power, but also a key component in constructing a self-stabilizing system.

[0194] In Comparative Example 10, the liquefied petroleum gas (propane / isobutane) is a typical nonpolar molecule. Its molecules exhibit only weak van der Waals forces and lack the ability to form hydrogen bonds. Therefore, it cannot participate in the hydrogen bond network constructed by the alcohol solvent and the hydroxyl groups on the powder surface in this system. The lack of synergistic stabilizing effect of the hydrofluorocarbon propellant means the system cannot resist particle sedimentation for extended periods.

[0195] In Comparative Example 11, the dimethyl ether (DME) molecule contains one ether oxygen atom, which can act as a hydrogen bond acceptor. However, its long-term stability is still significantly worse than that of Example 1. This indicates that although DME can partially participate in hydrogen bonding, its molecular structure and electron cloud distribution are fundamentally different from those of hydrofluorocarbon propellants, resulting in insufficient strength, directionality, and stability of its hydrogen bonds to construct the optimal three-dimensional network structure.

[0196] Fluorine atoms in HFA / HFO type hydrofluorocarbon propellant molecules, such as tetrafluoroethane, possess extremely high electronegativity and act as excellent hydrogen bond acceptors. They can form hydrogen bonds of moderate strength and with matching spatial configurations with the hydroxyl hydrogens of C2-C4 monohydric alcohol solvents and the hydroxyl groups on the powder surface through controlled processes. This interaction allows the hydrofluorocarbon propellant molecules to connect to the solvation layer and enhance the network structure, thereby achieving a synergistic self-stabilizing effect across the powder-liquid-gas three-phase system.

[0197] The hydrofluorocarbon propellant described in this invention is an essential component for achieving a high-performance, dispersant-free, self-stabilizing system. Its specific physicochemical properties can produce a synergistic stabilizing effect with monohydric alcohol solvents.

[0198] (5) Traditional dispersant addition scheme: Comparative Example 12 has good initial dispersibility, but the dispersant becomes ineffective after standing, and the powder is difficult to redisperse.

[0199] In summary, this invention, by controlling the surface hydroxyl density of glass-ceramic powder within a specific range and using a monohydric alcohol as a solvent and hydrofluorocarbons as a propellant, together constitutes an aerosol system that can achieve long-term storage stability without the addition of external dispersants. This system is superior to the scheme that adds dispersants in terms of process feasibility and has broad application prospects.

[0200] The present invention has been illustrated with the above embodiments to illustrate its detailed features, but the present invention is not limited to the above detailed features, that is, it does not mean that the present invention must rely on the above detailed features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the selected technical features, additions of auxiliary technical features, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An aerosol, characterized in that, The aerosol includes glass ceramic powder, monohydric alcohol solvent, and hydrofluorocarbon propellant; The Fourier transform infrared spectrum of the glass-ceramic powder is in the range of 3400~3500 cm⁻¹. -1 The area of ​​the characteristic hydroxyl peak at 440~480 cm⁻¹ is similar to that at 440~480 cm⁻¹. -1 The ratio of the characteristic peak areas of the symmetric stretching vibration of the silicon-oxygen bond at a given point is denoted as R. OH The R OH The value ranges from 0.1 to 0.

8.

2. The aerosol according to claim 1, characterized in that, The aerosol comprises, by weight percentage: 5-30 wt% glass-ceramic powder; 5-45 wt% monohydric alcohol solvent; and 25-90 wt% hydrofluorocarbon propellant.

3. The aerosol according to claim 1 or 2, characterized in that, The monohydric alcohol solvent has 2 to 4 carbon atoms; Preferably, the monohydric alcohol solvent includes any one or a combination of at least two of ethanol, isopropanol, n-propanol, isobutanol, sec-butanol, or n-butanol.

4. The aerosol according to any one of claims 1 to 3, characterized in that, The hydrofluorocarbon propellant includes hydrofluoroolefins and / or hydrofluoroalkanes; Preferably, the hydrofluorocarbon propellant comprises any one or a combination of at least two of tetrafluoroethane, tetrafluoropropylene, heptafluoropropane, or difluoroethane.

5. The aerosol according to any one of claims 1 to 4, characterized in that, Based on the mass of the glass-ceramic powder (100%), the composition of the glass-ceramic powder includes SiO2: 55~85wt%; Li2O: 8~20wt%; Preferably, the glass-ceramic powder further includes a nucleating agent and / or additives; Preferably, the particle size range of the glass-ceramic powder is 0.3~60μm; Preferably, the particle size D50 of the glass-ceramic powder is 1~30μm.

6. An aerosol product, characterized in that, The aerosol product includes a can, a valve, and the aerosol as described in any one of claims 1 to 5 encapsulated in the can.

7. A method for preparing an aerosol according to any one of claims 1 to 5 or an aerosol product according to claim 6, characterized in that, The preparation method includes: (1) The glass ceramic powder raw material is calcined to reduce the R of the glass ceramic powder. OH The concentration is 0.1~0.8, resulting in processed glass-ceramic powder; (2) Mix the treated glass-ceramic powder described in step (1) with a monohydric alcohol solvent to prepare a slurry; (3) Fill the tank with the slurry described in step (2) and seal it; (4) Press hydrofluorocarbon propellant into the sealed tank after step (3).

8. The preparation method according to claim 7, characterized in that, The calcination temperature in step (1) is 400~600℃; Preferably, the calcination treatment time is 1-4 hours; Preferably, the particle size of the glass-ceramic powder raw material is 0.3~60μm; Preferably, the particle size D50 of the glass-ceramic powder raw material is 1~30μm; Preferably, the pressure inside the tank after the hydrofluorocarbon propellant is injected is 0.2~0.9 MPa.

9. The application of an aerosol product according to any one of claims 1 to 5 and / or claim 6, characterized in that, The aerosol is used to treat the surface of zirconium oxide.

10. The application according to claim 9, characterized in that, The zirconium oxide is a zirconium oxide denture; Preferably, the application includes: (1) The aerosol is sprayed onto the bonding surface of the zirconia denture to obtain the treated denture; (2) The surface of the denture after the treatment in step (1) is sintered to form a glass-ceramic layer on the surface of the zirconia denture; Preferably, the sintering temperature is 800~950℃; Preferably, the sintering time is 10-40 minutes; Preferably, the bonding strength between the glass-ceramic layer and the resin cement is 18MPa~45MPa.

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