Buzzer sealant and preparation method thereof

Abstract

The invention discloses a buzzer sealant and a preparation method thereof, and relates to the technical field of sealant preparation, the buzzer sealant comprises 30-60 parts of a basic polymer, 5-20 parts of a curing agent, 10-40 parts of a filler, 5-15 parts of a flexibilizer, 0.1-1 part of an antifoaming agent, and 0.01-5 parts of other additives; the preparation method of the sealant comprises the following steps: S1, preparing and weighing raw materials; s2, primary treatment of the raw materials; s3, stirring and mixing; s4, carrying out defoaming treatment; and S5, potting or coating. According to the buzzer sealant and the preparation method thereof, the formula of the sealant is strictly designed, the proportion of each component is accurately adjusted, and the epoxy resin and the polyurethane are blended according to different use temperatures and different proportions, so that the prepared sealant has an excellent curing effect and can form a compact and pore-free protective layer; and the external environment is effectively isolated, so that the stable work of the buzzer is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of sealant preparation, in particular to a buzzer sealant and a preparation method thereof. Background Art

[0002] Buzzer sealant is a sealing material specifically designed for buzzers. It deforms to the shape of the sealing surface, resists flow, and exhibits a certain degree of adhesion. This sealant primarily fills the gaps within the buzzer's internal structure to achieve a sealing effect, playing a crucial role in the buzzer production process. By potting the sealant, the internal components of the buzzer are protected from external corrosion, improving the device's mechanical strength and durability. The sealant also provides sound and heat insulation, enhancing the performance and stability of the buzzer.

[0003] Sealant curing, the process by which a sealant transforms from a liquid or semi-fluid state to a solid state, is crucial for the sealant. Curing rearranges the sealant's molecular structure, forming a stable cross-linked network that imparts excellent mechanical strength, elasticity, chemical resistance, and thermal stability. For buzzers, maintaining these properties is essential for long-term, reliable operation in complex environments.

[0004] However, in the prior art, the curing effect of buzzer sealant often depends on the ingredients and formula, which directly affects its curing time. The existing buzzer seal usually has a poor curing effect, which makes the sealant prone to problems such as incomplete curing or too fast curing speed, so that the sealant cannot form a tight sealing layer, thereby affecting the waterproof and dustproof performance of the buzzer. Summary of the Invention

[0005] The object of the present invention is to provide a buzzer sealant and a preparation method thereof to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In one aspect, a buzzer sealant is provided, comprising the following components in parts by mass: 30 to 60 parts of a base polymer, 5 to 20 parts of a curing agent, 10 to 40 parts of a filler, 5 to 15 parts of a toughening agent, 0.1 to 1 part of a defoaming agent, and 0.01 to 5 parts of other additives;

[0008] The base polymer is formed by blending epoxy resin and polyurethane in a ratio of (7-8): (2-3), and is used to provide the main structure of the sealant and determine its basic mechanical properties (such as strength and elasticity) and chemical stability;

[0009] The curing agent is one of an amine curing agent, an organic metal compound, and a peroxide, and is used to react with the base polymer to promote cross-linking and curing to form a stable solid structure;

[0010] The filler is at least one of silicon dioxide, calcium carbonate, talc, and aluminum oxide, and is used to adjust viscosity, increase hardness, improve thermal conductivity, reduce cost, and may affect curing shrinkage and color;

[0011] The defoamer is a silicone defoamer, specifically BYK-A525 (polyether-modified methylsiloxane copolymer solution with a density of 0.86 g / ml (20° C.), prepared using a solvent of 9:1 white spirit and propylene glycol methyl ether acetate) or BYK-A530 (excellent in epoxy systems, a highly effective silicone and polymer defoamer), which is used to prevent bubbles from forming during the mixing and curing process, ensuring that the sealant is free of pores.

[0012] The toughening agent is selected from rubber elastomers and flexible segment polymers to improve the flexibility and crack resistance of the sealant, especially in low temperature or vibration environments;

[0013] The other additives include pigments (for coloring), antioxidants (for improving weather resistance), coupling agents (for enhancing interfacial adhesion), compatibilizers (for improving compatibility between different polymers and reducing stratification and phase separation), etc., which are added according to specific needs.

[0014] Furthermore, the blending ratio of the epoxy resin and the polyurethane is determined by the ambient temperature of the sealant, as follows:

[0015] 1) The sealant is used in an environment with an ambient temperature higher than 25°C. The ratio of epoxy resin to polyurethane is 8:2. As the temperature is high, the epoxy resin cures quickly. Reduce the polyurethane ratio to prevent curing delay.

[0016] 2) The sealant is used in an environment with an ambient temperature below 5°C. The ratio of epoxy resin to polyurethane is 7:3. At low temperatures, in order to improve fluidity, increase the proportion of polyurethane and improve processing performance.

[0017] 3) The operating environment temperature of the sealant is 5-25°C, and the ratio of epoxy resin to polyurethane is (7-8): (2-3). For every 1°C increase in temperature, the proportion of epoxy resin increases by 0.05 and the proportion of polyurethane decreases by 0.05.

[0018] Furthermore, the specific selection of the curing agent is as follows:

[0019] Amine curing agent: polyamide resin, ethylenediamine, diethylenetriamine;

[0020] Organometallic compounds: dibutyltin dilaurate (DBTDL), diethylstannate;

[0021] Peroxides: methyl ethyl ketone peroxide (MEKP), benzoyl peroxide (BPO), tert-butyl hydroperoxide.

[0022] Furthermore, the filler includes two particle size specifications, namely fine particles of 50 to 80 microns and medium particles of 300 to 500 microns, and the mass ratio of medium particles to fine particles in the filler is 4:1. Among them, the medium particles have relatively low cost and good processability, and can meet the sealing requirements of most buzzers, while the fine particles can better fill tiny gaps and improve sealing.

[0023] Furthermore, the toughening agent is specifically as follows:

[0024] Rubber elastomer: a highly elastic polymer with a high elastic modulus and a low glass transition temperature, which can give the sealant excellent resistance to low-temperature brittleness, including but not limited to liquid polysulfide rubber, liquid polybutadiene rubber, nitrile rubber, ethylene propylene rubber and styrene butadiene rubber;

[0025] Flexible chain segment polymer: A polymer compound containing flexible chain segments, whose mechanism of action is to effectively absorb impact energy by forming physical or chemical cross-linking points with the matrix resin, thereby improving the toughness of the buzzer sealant, including but not limited to styrene-butadiene thermoplastic elastomer (SBS) and polyurethane thermoplastic elastomer (TPU).

[0026] On the other hand, a method for preparing a buzzer sealant is provided, which is applied to the buzzer sealant as described above, and comprises the following steps:

[0027] S1. Raw material preparation and weighing: Prepare all raw materials according to the formula requirements, including base polymer, curing agent, filler, toughening agent, defoaming agent and other additives, and weigh the amount of each raw material in turn to ensure the accurate ratio;

[0028] S2. Preliminary processing of raw materials:

[0029] S21, blending epoxy resin and polyurethane in proportion to form an interpenetrating polymer network (IPN) structure to obtain a base polymer;

[0030] S22, dividing the filler into two parts with a mass ratio of 4:1, and crushing them into medium particles and fine particles respectively;

[0031] S3, stirring and mixing: the raw materials are sequentially put into the mixing container, and the stirrer is started to stir until all the raw materials are evenly mixed to obtain the semi-finished sealant;

[0032] S4, defoaming treatment: use vacuum degassing to extract bubbles from the semi-finished sealant;

[0033] S5. Potting or coating: Pour the prepared sealant into the sealing part of the buzzer, or use a brush, scraper or other tool to apply it to the area that needs to be sealed. During the potting or coating process, it is necessary to ensure that the sealant is evenly distributed and avoid the formation of bubbles or gaps.

[0034] Furthermore, in step S22, an ultrafine grinding device (such as an HGM80 micro powder mill) or a vertical mill (such as an HLMX ultrafine vertical mill) is used to crush the filler into fine particles of 50 to 80 microns, and a vibrating screen or a wheel bucket sand washing machine is used to adjust the medium particles of 300 to 500 microns.

[0035] Furthermore, in step S3, the agitator is a planetary mixer, and the agitation rotation speed of the planetary mixer is 140±5 r / min, the revolution speed is 60±5 r / min, and the agitation time is controlled at 10 to 15 minutes.

[0036] Furthermore, the specific operation of step S4 is as follows: placing the semi-finished sealant product in a vacuum container, reducing the air pressure in the container by vacuuming, causing the bubbles to expand and burst, and finally be extracted.

[0037] Furthermore, the target vacuum degree of the vacuum degassing is 10 -3 Pa, and the vacuum degassing is divided into three stages: initial stage, intermediate stage, and final stage. The vacuum degree in each stage gradually increases. The specific vacuum degree increase rate is as follows:

[0038] Initial stage: Starting from atmospheric pressure, gradually increase the vacuum degree at a rate of 1 order of magnitude per minute until it reaches 10 -1 Pa, due to the high bubble content in the sealant, a large number of bubbles can be quickly discharged by increasing the vacuum degree appropriately and quickly;

[0039] Intermediate stage: in 10 -2 Pa, with the increase of vacuum degree and the gradual reduction of bubbles, the lifting rate is gradually slowed down, decreasing by 1 order of magnitude or slower every 5 minutes;

[0040] Final stage: Nearly 10 -3 When the vacuum level reaches 0.05 Pa, the lifting rate is further slowed down to stably reach the required vacuum level, and it is reduced by 1 order of magnitude every 10 minutes or even longer until the target vacuum level is stably reached.

[0041] The present invention provides a buzzer sealant and a preparation method thereof, which have the following beneficial effects:

[0042] The present invention strictly designs the sealant formula and accurately adjusts the proportion of each component. In addition, according to different operating temperatures, epoxy resin and polyurethane are blended in different proportions, so that the prepared sealant has excellent curing effect, can form a dense, non-porous protective layer, effectively isolate the external environment, and thus ensure the stable operation of the buzzer. At the same time, the present invention effectively reduces the possibility of bubbles generated during the mixing and curing process by adding a defoaming agent and defoaming treatment in the preparation process, ensuring the uniformity and density of the sealing layer, making it less likely to crack or fall off after curing. In addition, the sealant has an appropriate viscosity, which is convenient for potting or coating on the sealing part of the buzzer, and can be quickly cured to improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention is a flowchart of the steps of a method for preparing a buzzer sealant. DETAILED DESCRIPTION

[0044] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0045] A buzzer sealant comprising the following components in parts by mass: 50 parts of a base polymer, 15 parts of a curing agent, 25 parts of a filler, 10 parts of a toughening agent, 0.5 parts of a defoaming agent, and 0.05 parts of other additives;

[0046] Base polymer: Epoxy resin and polyurethane are blended in a ratio of (7-8): (2-3). This provides the sealant's main structure and determines its basic mechanical properties (such as strength and elasticity) and chemical stability. In this embodiment, the blend ratio of epoxy resin and polyurethane is determined by the ambient temperature of the sealant, as follows:

[0047] 1) The sealant is used in an environment with an ambient temperature higher than 25°C. The ratio of epoxy resin to polyurethane is 8:2. As the temperature is high, the epoxy resin cures quickly. Reduce the polyurethane ratio to prevent curing delay.

[0048] 2) The sealant is used in an environment with an ambient temperature below 5°C. The ratio of epoxy resin to polyurethane is 7:3. At low temperatures, in order to improve fluidity, increase the proportion of polyurethane and improve processing performance.

[0049] 3) The operating environment temperature of the sealant is 5-25°C, and the ratio of epoxy resin to polyurethane is (7-8): (2-3). For every 1°C increase in temperature, the proportion of epoxy resin increases by 0.05 and the proportion of polyurethane decreases by 0.05.

[0050] Curing agent: Select an amine curing agent, specifically polyamide resin, ethylenediamine or diethylenetriamine, to react with the base polymer to promote cross-linking and curing to form a stable solid structure.

[0051] Fillers: Silica and talc are selected to adjust viscosity, increase hardness, improve thermal conductivity, reduce cost, and may affect cure shrinkage and color. In this embodiment, the fillers include two particle sizes: fine particles (silicon dioxide) with a diameter of 50 to 80 microns and medium particles (talc) with a diameter of 300 to 500 microns. The mass ratio of medium particles to fine particles in the filler is 4:1. The medium particles are relatively low in cost and have better processability, meeting the sealing requirements of most buzzers, while the fine particles can better fill tiny gaps and improve sealing.

[0052] Defoamer: Choose a silicone defoamer, specifically BYK-A525 (polyether-modified methylsiloxane copolymer solution with a density of 0.86 g / ml (20°C) and a solvent of 9:1 white spirit and propylene glycol methyl ether acetate) or BYK-A530 (excellent in epoxy systems, a high-efficiency silicone and polymer defoamer) to prevent bubbles from forming during mixing and curing to ensure there are no pores inside the sealant.

[0053] Toughening agent: Select a flexible chain segment polymer, specifically styrene-butadiene thermoplastic elastomer (SBS), which effectively absorbs impact energy by forming physical or chemical cross-linking points with the matrix resin, thereby improving the toughness of the buzzer sealant. It is used to improve the flexibility and crack resistance of the sealant, especially in low temperature or vibration environments.

[0054] Other additives: including pigments (coloring), antioxidants (improving weather resistance), coupling agents (enhancing interfacial adhesion), compatibilizers (improving the compatibility between different polymers and reducing stratification and phase separation), etc., are added according to specific needs.

[0055] like Figure 1 As shown, a method for preparing a buzzer sealant is applied to the buzzer sealant as described above, comprising the following steps:

[0056] S1. Raw material preparation and weighing: Prepare all raw materials according to the formula requirements, including base polymer, curing agent, filler, toughening agent, defoaming agent and other additives, and weigh the amount of each raw material in turn to ensure the accurate ratio;

[0057] S2. Preliminary processing of raw materials:

[0058] S21. Blending epoxy resin and polyurethane in proportion to form an interpenetrating polymer network (IPN) structure to obtain a base polymer.

[0059] S22. The mass ratio of filler silica to talc is 4:1. Use ultrafine grinding equipment (such as HGM80 micro powder mill) to crush silica into fine particles of 50 to 80 microns, and use a vibrating screen or a wheel bucket sand washing machine to adjust and obtain medium-particle talc powder of 300 to 500 microns.

[0060] S3. Stirring and mixing: put the raw materials into the mixing container in sequence, start the agitator for stirring, select a planetary mixer, and the stirring rotation speed of the planetary mixer is 140±5r / min, the revolution speed is 60±5r / min, and the stirring time is controlled at 10 to 15 minutes until all the raw materials are evenly mixed to obtain a semi-finished sealant product.

[0061] S4, defoaming treatment: Place the semi-finished sealant product in a vacuum container, reduce the air pressure in the container by vacuuming, so that the bubbles expand and burst, and are finally extracted;

[0062] In this embodiment, the target vacuum degree of vacuum degassing is 10 -3 Pa, and the vacuum degassing is divided into three stages: initial stage, intermediate stage, and final stage. The vacuum degree in each stage gradually increases. The specific vacuum degree increase rate is as follows:

[0063] Initial stage: Starting from atmospheric pressure, gradually increase the vacuum degree at a rate of 1 order of magnitude per minute until it reaches 10 -1 Pa, due to the high bubble content in the sealant, a large number of bubbles can be quickly discharged by increasing the vacuum degree appropriately and quickly;

[0064] Intermediate stage: in 10 -2 Pa, as the vacuum degree increases and the bubbles gradually decrease, the lifting rate is gradually slowed down, decreasing by 1 order of magnitude every 5 minutes or slower. At this stage, the change of vacuum degree needs to be controlled more carefully to ensure that the bubbles can be fully released without causing other problems;

[0065] Final stage: Nearly 10 -3 When the vacuum level reaches 0.05 Pa, the lifting rate is further slowed down to stably reach the required vacuum level, and it is reduced by 1 order of magnitude every 10 minutes or even longer until the target vacuum level is stably reached. Special care is required at this stage to avoid degradation of sealant performance due to improper operation.

[0066] S5. Potting or coating: Pour the prepared sealant into the sealing part of the buzzer, or use a brush, scraper or other tool to apply it to the area that needs to be sealed. During the potting or coating process, it is necessary to ensure that the sealant is evenly distributed and avoid the formation of bubbles or gaps.

[0067] The embodiments of the present invention are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments are chosen and described in order to better illustrate the principles of the invention and its practical application and to enable those skilled in the art to understand the invention and design various embodiments with various modifications as suited for specific applications.

Claims

1. A buzzer sealant, characterized in that: The invention comprises the following components in parts by weight: 30 to 60 parts of base polymer, 5 to 20 parts of curing agent, 10 to 40 parts of filler, 5 to 15 parts of toughening agent, 0.1 to 1 part of defoaming agent, and 0.01 to 5 parts of other additives; The base polymer is prepared by blending epoxy resin and polyurethane in a ratio of (7-8): (2-3); The curing agent is one of an amine curing agent, an organometallic compound, and a peroxide; The filler is at least one of silicon dioxide, calcium carbonate, talc, and aluminum oxide; The defoamer is an organosilicon defoamer, specifically BYK-A525 or BYK-A53; The toughening agent is selected from rubber elastomer and flexible segment polymer; The other additives include pigments, antioxidants, coupling agents, and compatibilizers.

2. The buzzer sealant according to claim 1, characterized in that: The blending ratio of the epoxy resin and polyurethane is determined by the ambient temperature of the sealant, as follows: 1) When the sealant is used in an environment with an ambient temperature higher than 25°C, the ratio of epoxy resin to polyurethane should be 8:

2. When the temperature is high, reduce the polyurethane ratio to prevent curing delay. 2) The operating temperature of the sealant is below 5°C, and the ratio of epoxy resin to polyurethane is 7:

3. At low temperatures, increasing the proportion of polyurethane can improve processing performance. 3) The operating environment temperature of the sealant is 5-25°C, and the ratio of epoxy resin to polyurethane is (7-8): (2-3). For every 1°C increase in temperature, the proportion of epoxy resin increases by 0.05 and the proportion of polyurethane decreases by 0.

05.

3. The buzzer sealant according to claim 1, characterized in that: The specific selection of the curing agent is as follows: Amine curing agent: polyamide resin, ethylenediamine, diethylenetriamine; Organometallic compounds: dibutyltin dilaurate (DBTDL), diethylstannate; Peroxides: methyl ethyl ketone peroxide (MEKP), benzoyl peroxide (BPO), tert-butyl hydroperoxide.

4. The buzzer sealant according to claim 1, characterized in that: The filler includes two particle size specifications, namely fine particles of 50 to 80 microns and medium particles of 300 to 500 microns, and the mass ratio of the medium particles to the fine particles in the filler is 4:

1.

5. The buzzer sealant according to claim 1, characterized in that: The toughening agent is specifically as follows: Rubber elastomers: highly elastic polymers, including liquid polysulfide rubber, liquid polybutadiene rubber, nitrile rubber, ethylene propylene rubber and styrene butadiene rubber; Flexible segment polymer: a polymer compound containing flexible segments, including styrene-butadiene thermoplastic elastomer and polyurethane thermoplastic elastomer.

6. A method for preparing a buzzer sealant, applied to the buzzer sealant according to claims 1-5, characterized in that: The following steps are involved: S1. Raw material preparation and weighing: Prepare all raw materials according to the recipe requirements and weigh the amount of each raw material in turn; S2. Preliminary processing of raw materials: S21, blending epoxy resin and polyurethane in proportion to form an interpenetrating polymer network structure to obtain a base polymer; S22, dividing the filler into two parts with a mass ratio of 4:1, and crushing them into medium particles and fine particles respectively; S3, stirring and mixing: the raw materials are sequentially put into the mixing container, and the stirrer is started to stir until all the raw materials are evenly mixed to obtain the semi-finished sealant; S4, defoaming treatment: use vacuum degassing to extract bubbles from the semi-finished sealant; S5. Potting or coating: Pour the prepared sealant into the sealing part of the buzzer, or use a tool to apply it to the area that needs to be sealed.

7. The method for preparing buzzer sealant according to claim 6, characterized in that: In step S22, the filler is crushed into fine particles of 50 to 80 microns using an ultrafine grinding device or a vertical grinding mill, and medium particles of 300 to 500 microns are obtained by adjusting the size of the filler using a vibrating screen or a wheel bucket sand washer.

8. The method for preparing buzzer sealant according to claim 6, characterized in that: In step S3, a planetary mixer is selected as the stirrer, and the stirring rotation speed of the planetary mixer is 140±5 r / min, the revolution speed is 60±5 r / min, and the stirring time is controlled at 10 to 15 minutes.

9. The method for preparing buzzer sealant according to claim 6, characterized in that: The specific operation of step S4 is as follows: placing the semi-finished sealant product in a vacuum container, reducing the air pressure in the container by vacuuming, causing the bubbles to expand and burst, and finally be extracted.

10. The method for preparing buzzer sealant according to claim 9, characterized in that: The target vacuum degree of the vacuum degassing is 10 -3 Pa, and the vacuum degassing is divided into three stages: initial stage, intermediate stage, and final stage. The vacuum degree in each stage gradually increases. The specific vacuum degree increase rate is as follows: Initial stage: Starting from atmospheric pressure, gradually increase the vacuum degree at a rate of 1 order of magnitude per minute until it reaches 10 -1 Pa around; Intermediate stage: in 10 -2 Pa, gradually slow down the rate of increase, reducing it by 1 order of magnitude or slower every 5 minutes; Final stage: Nearly 10 -3 Pa, further slow down the lifting rate, reducing it by one order of magnitude every 10 minutes or even longer, until the target vacuum degree is stably reached.

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