A waterproof and breathable adhesive and a preparation method and application thereof

Abstract

The application provides waterproof and breathable glue and a preparation method and application thereof, and the preparation raw material of the waterproof and breathable glue comprises the following components: an acrylic ester monomer, a polyurethane acrylic ester oligomer, a pore opener, a foaming agent, a photoinitiator, a hydrophobic aid and a filler. The waterproof and breathable glue has the characteristics of fast curing speed and good waterproof and breathable effect through the compounding of the acrylic ester monomer, the polyurethane acrylic ester oligomer, the pore opener, the foaming agent, the photoinitiator, the hydrophobic aid and the filler.

Description

Technical Field

[0001] This invention belongs to the field of colloid technology, specifically relating to a waterproof and breathable adhesive, its preparation method, and its application. Background Technology

[0002] In the camera module manufacturing process, adhesive is used to seal the vent holes, followed by centrifugal washing, baking, and finally, removal of the adhesive before installation. During the washing process, water or steam can easily enter the vent holes. During baking or prolonged use, the internal temperature rises, gas volume expands, and internal pressure increases, potentially leading to vent bursts or damage to camera components. Therefore, a waterproof and breathable adhesive is needed to seal the vent holes. Silicone sealant has excellent waterproof and breathable properties, making it the most common adhesive used for vent holes on the market. However, silicone sealant has a long curing time, typically requiring over 24 hours to fully cure, resulting in low production efficiency.

[0003] CN115505370A discloses a method for preparing a waterproof and breathable adhesive, its product, and its application. The preparation method includes uniformly mixing terminal alkoxy polydimethylsiloxane, hydrogen-containing silicone oil, calcium oxide, aluminum oxide, ferric oxide, silicon dioxide, sodium carbonate, and acetylene black; adding methyltrimethoxysilane dropwise to obtain a base adhesive; then reacting the mixture in a muffle furnace at high temperature; cooling the adhesive to 90-100°C; adding ethanol and stirring until homogeneous; and then subjecting the adhesive to ultra-low temperature quenching at 25°C; finally, adding terminal hydroxyl polydimethylsiloxane and hydrogen-containing silicone oil and mixing; and then adding a chelated tin catalyst and stirring until homogeneous to obtain the waterproof and breathable adhesive. The waterproof and breathable adhesive prepared by this method can form uniform micron-sized pores after curing, possessing both waterproof and breathable properties, but it requires preparation at 1400-1600°C and the preparation process is complex.

[0004] Therefore, there is a need to develop a waterproof and breathable adhesive that has a fast curing speed, a simple preparation process, and good waterproof and breathable properties. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a waterproof and breathable adhesive, its preparation method, and its applications. The waterproof and breathable adhesive prepared by compounding components such as acrylate monomers, polyurethane acrylate oligomers, cell openers, foaming agents, photoinitiators, hydrophobic additives, and fillers exhibits characteristics of rapid curing and excellent waterproof and breathable properties.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a waterproof and breathable adhesive, wherein the raw materials for preparing the waterproof and breathable adhesive include the following components: acrylate monomers, polyurethane acrylate oligomers, cell openers, foaming agents, photoinitiators, hydrophobic additives, and fillers.

[0008] In this invention, the waterproof and breathable adhesive cures under ultraviolet light, releasing a large amount of heat during the curing process. This causes the foaming agent to decompose, releasing gases and free radicals. The free radicals further promote the polymerization of acrylate monomers and polyurethane acrylate oligomers, accelerating the polymerization process. The temperature generated during polymerization further accelerates the decomposition of the foaming agent, causing the waterproof and breathable adhesive to rapidly foam and expand, reducing the crosslinking density. Simultaneously, under the action of the opening agent, the bubbles rupture, forming through-cell or honeycomb structures. When water exists in the form of water vapor, the water vapor and other gas particles are small and, according to the principle of capillary motion, can easily permeate through the capillary to the other side, thus achieving breathability. When water vapor condenses into water droplets, forming liquid water, the particles become larger. Due to the surface tension of the water droplets, water molecules cannot easily detach from the droplets and permeate to the other side, thus preventing the penetration of liquid water and achieving a waterproof effect.

[0009] Preferably, the raw materials for preparing the waterproof and breathable adhesive include the following components by mass percentage: 25-55% acrylate monomers (e.g., 25%, 30%, 32%, 35%, 40%, 42%, 45%, 50%, 52%, or 55%), 30-62% polyurethane acrylate oligomers (e.g., 30%, 32%, 35%, 38%, 40%, 42%, 45%, 48%, 50%, 55%, or 62%), and 0.1-1% pore-opening agent (e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%). 9% or 1%, etc.), foaming agent 1-3% (e.g., 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8% or 3%, etc.), photoinitiator 3-5% (e.g., 3%, 3.2%, 3.5%, 3.8%, 4%, 4.2%, 4.5%, 4.8% or 5%, etc.), hydrophobic additive 0.5-2% (e.g., 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.6%, 1.7% or 2%, etc.), and filler 1-5% (e.g., 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc.).

[0010] In this invention, the foaming agent has a mass percentage of 1-3%. If the content of the foaming agent is too low, the waterproof and breathable adhesive will not foam completely, the pores will not be connected, which is not conducive to the formation of a through-pore structure and the breathability of the waterproof and breathable adhesive will be poor. If the content of the foaming agent is too high, the waterproof and breathable adhesive will foam excessively, the formed pores will be too large, the capillary effect will be reduced, water will enter during centrifugal washing, and the waterproof effect will be poor.

[0011] In this invention, the photoinitiator has a mass percentage of 3-5%. If the photoinitiator content is too low, the photocuring speed will be slower after UV irradiation, less heat will be released, the foaming agent will decompose later and incompletely, the waterproof and breathable adhesive will not foam completely, and it will fail to form a through-pore or honeycomb structure. Slight bursting will occur when baking at 85°C, and the breathability will deteriorate. If the photoinitiator content is too high, the curing speed will be too fast, a large amount of heat will be released, the waterproof and breathable adhesive will foam excessively, the pore structure will be too large, and water droplets will easily enter the module through the adhesive layer, resulting in poor waterproof performance.

[0012] Preferably, the acrylate monomers include any one or a combination of at least two of the following: isobornyl acrylate, hydroxyethyl methacrylate, tetrahydrofuran acrylate, tetrahydrofuran methacrylate, ethoxytetrahydrofuran acrylate, trimethylolcyclohexyl acrylate, cyclotrimethylolpropane methyl acetal acrylate, dodecyl acrylate, or isodecanyl acrylate.

[0013] Preferably, the polyurethane acrylate oligomer includes aliphatic polyurethane acrylate oligomers.

[0014] Preferably, the aliphatic polyurethane acrylate oligomer is obtained by polymerization of raw materials including polypropylene glycol, diisocyanate and hydroxyethyl acrylate.

[0015] Preferably, the pore-opening agent comprises any one or a combination of at least two of the following: Voranol CP1421 from Dow Chemical, Desmophen 41WB01 from Bayer, or DC-2525 from Dow Corning.

[0016] In this invention, the cell opener is a special surfactant containing both hydrophilic and hydrophobic groups, which can reduce the surface tension of the foam during the foaming process, promote the breaking of the cells, and form a through-hole or honeycomb structure.

[0017] Preferably, the foaming agent comprises azobisisobutyronitrile (AIBN).

[0018] In this invention, the foaming agent includes azobisisobutyronitrile (AIBN). Each part of AIBN decomposes and releases one part of N2 and one part of free radicals. The free radicals further promote the polymerization of acrylate monomers and polyurethane acrylate oligomers, thus accelerating the polymerization process. The temperature generated during the polymerization process further accelerates the decomposition of AIBN.

[0019] Preferably, the photoinitiator comprises any one or a combination of at least two of the following: 1-hydroxycyclohexylphenyl ketone, 2,4,6-(trimethylbenzoyl)diphenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, methyl benzoylformate, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-isopropylthioxanthone, benzoin dimethyl ether, dimethylbenzoyl ketal, or benzophenone; more preferably, a mixture of 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0020] Preferably, the hydrophobic additive comprises cage-type polysilsesquioxane.

[0021] In this invention, the cage-shaped polysilsesquioxane has a unique three-dimensional structure, which can increase the strength of the foamed waterproof and breathable adhesive, prevent the collapse of the through-pore structure of the waterproof and breathable adhesive, and at the same time increase the hydrophobic effect of the waterproof and breathable adhesive.

[0022] Preferably, the cage-like polysilsesquioxane comprises methacryloyloxypropylheptaisobutyl cage-like polysilsesquioxane.

[0023] In this invention, the cage-like polysilsesquioxane includes methacryloyloxypropylheptaisobutyl cage-like polysilsesquioxane. This is because the seven isobutyl groups at the cage-like ends of the methacryloyloxypropylheptaisobutyl cage-like polysilsesquioxane can modify the pores, thus exhibiting good hydrophobic properties.

[0024] Preferably, the filler comprises hydrophobic fumed silica.

[0025] In a second aspect, the present invention provides a method for preparing the waterproof and breathable adhesive as described in the first aspect, the method comprising the following steps: mixing acrylate monomers, polyurethane acrylate oligomers, pore-opening agents, foaming agents, photoinitiators, hydrophobic additives and fillers to obtain the waterproof and breathable adhesive.

[0026] Preferably, the mixing method is as follows:

[0027] (1) Mix acrylate monomers, polyurethane acrylate oligomers and pore openers to obtain a mixed solution.

[0028] (2) Mix the mixed solution described in step (1) with the foaming agent, photoinitiator, hydrophobic additive and filler.

[0029] Thirdly, the present invention provides an application of the waterproof and breathable adhesive as described in the first aspect in the camera module manufacturing process.

[0030] In this invention, the waterproof and breathable adhesive cures under ultraviolet light to form a porous or honeycomb structure, which allows water vapor and other gases to pass through, thereby balancing the air pressure inside and outside the camera module and preventing liquid water from penetrating in, thus avoiding malfunctions of the camera and breakage of the filter.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention utilizes a compounding process of acrylate monomers, polyurethane acrylate oligomers, pore-opening agents, foaming agents, photoinitiators, hydrophobic additives, and fillers to produce a waterproof and breathable adhesive that forms a porous or honeycomb structure. This adhesive features a simple preparation process, rapid curing, and excellent waterproof and breathable properties. Furthermore, the adhesive has a short curing time, does not allow water to seep in during centrifugal washing, and does not burst after baking at 85°C. Detailed Implementation

[0033] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0034] Preparation Example 1

[0035] A polyurethane acrylate oligomer, the preparation method of which is as follows:

[0036] 25 parts by weight of polypropylene glycol PPG2000, 51.5 parts by weight of polypropylene glycol PPG4000, 0.05 parts by weight of hydroquinone, and 0.1 parts by weight of dibutyltin dilaurate were added to a three-necked flask and stirred thoroughly. The mixture was heated to 105°C and vacuum-dried for 1 hour to remove water. Then, the temperature was lowered to 65°C, and 13.5 parts by weight of isophorone diisocyanate were added. The reaction was allowed to proceed for 2 hours. After the reaction was complete, the temperature was lowered to 45°C, and 9 parts by weight of hydroxyethyl acrylate were slowly added dropwise using a constant pressure dropping funnel. After the addition was complete, the reaction temperature was maintained at 45°C until the reaction was complete, yielding the polyurethane acrylate oligomer.

[0037] In the following examples and comparative examples, "%" refers to the percentage by mass.

[0038] Example 1

[0039] This embodiment provides a waterproof and breathable adhesive and its preparation method. The raw materials for preparing the waterproof and breathable adhesive include 35% acrylate monomer (isoborneol acrylate), 50% polyurethane acrylate oligomer obtained in Preparation Example 1, 0.5% cell opener (Dow Chemical Voranol CP1421), 2.5% foaming agent (azobisisobutyronitrile), 5% photoinitiator, 2% hydrophobic additive (methacryloyloxypropyl heptaisobutyl cage-type polysilsesquioxane), and 5% filler (hydrophobic fumed silica Aerosil R202).

[0040] The aforementioned photoinitiator is a mixture of 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, with a mass ratio of 3:1.

[0041] The preparation method includes the following steps:

[0042] (1) The acrylate monomer, the polyurethane acrylate oligomer prepared in Example 1 and the pore-opening agent are mixed and stirred to disperse evenly to obtain a mixed solution.

[0043] (2) Add the foaming agent, photoinitiator, hydrophobic additive and filler to the mixed solution in step (1) and stir and disperse until the mixture is uniform and there are no insoluble particles, to obtain the waterproof and breathable adhesive.

[0044] Example 2

[0045] This embodiment provides a waterproof and breathable adhesive and its preparation method. The raw materials for preparing the waterproof and breathable adhesive include 55% acrylate monomer (hydroxyethyl methacrylate), 34% polyurethane acrylate oligomer obtained in Preparation Example 1, 0.5% cell opener (Bayer Desmophen 41WB01), 3% foaming agent (azobisisobutyronitrile), 3% photoinitiator, 1.5% hydrophobic additive (methacryloyloxypropyl heptaisobutyl cage polysilsesquioxane), and 3% filler (hydrophobic fumed silica Aerosil R202).

[0046] The aforementioned photoinitiator is a mixture of 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, with a mass ratio of 2:1 between the two.

[0047] The preparation method includes the following steps:

[0048] (1) The acrylate monomer, the polyurethane acrylate oligomer prepared in Example 1 and the pore-opening agent are mixed and stirred to disperse evenly to obtain a mixed solution.

[0049] (2) Add the foaming agent, photoinitiator, hydrophobic additive and filler to the mixed solution in step (1) and stir and disperse until the mixture is uniform and there are no insoluble particles, to obtain the waterproof and breathable adhesive.

[0050] Example 3

[0051] This embodiment provides a waterproof and breathable adhesive and its preparation method. The raw materials for preparing the waterproof and breathable adhesive include 45% acrylate monomer (tetrahydrofuran acrylate), 41.5% polyurethane acrylate oligomer obtained in Preparation Example 1, 0.5% cell opener (Dow Corning DC-2525), 3% foaming agent (azobisisobutyronitrile), 5% photoinitiator, 1% hydrophobic additive (methacryloyloxypropylheptaisobutyl cage polysilsesquioxane), and 4% filler (hydrophobic fumed silica Aerosil R202).

[0052] The aforementioned photoinitiator is a mixture of 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, with a mass ratio of 1:1 between the two.

[0053] The preparation method includes the following steps:

[0054] (1) The acrylate monomer, the polyurethane acrylate oligomer prepared in Example 1 and the pore-opening agent are mixed and stirred to disperse evenly to obtain a mixed solution.

[0055] (2) Add the foaming agent, photoinitiator, hydrophobic additive and filler to the mixed solution in step (1) and stir and disperse until the mixture is uniform and there are no insoluble particles, to obtain the waterproof and breathable adhesive.

[0056] Example 4

[0057] This embodiment provides a waterproof and breathable adhesive and its preparation method. The raw materials for preparing the waterproof and breathable adhesive include 48% acrylate monomer (ethoxytetrahydrofuran acrylate), 42% polyurethane acrylate oligomer obtained in Preparation Example 1, 1% cell opener (Dow Chemical Voranol CP1421), 1% foaming agent (azobisisobutyronitrile), 3% photoinitiator, 1% hydrophobic additive (methacryloyloxypropylheptaisobutyl cage polysilsesquioxane), and 4% filler (hydrophobic fumed silica Aerosil R202).

[0058] The aforementioned photoinitiator is a mixture of 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, with a mass ratio of 3:1.

[0059] The preparation method includes the following steps:

[0060] (1) The acrylate monomer, the polyurethane acrylate oligomer prepared in Example 1 and the pore-opening agent are mixed and stirred to disperse evenly to obtain a mixed solution.

[0061] (2) Add the foaming agent, photoinitiator, hydrophobic additive and filler to the mixed solution in step (1) and stir and disperse until the mixture is uniform and there are no insoluble particles, to obtain the waterproof and breathable adhesive.

[0062] Example 5

[0063] This embodiment provides a waterproof and breathable adhesive and its preparation method. The raw materials for preparing the waterproof and breathable adhesive include 25% acrylate monomer (trimethylolcyclohexyl acrylate), 61.4% polyurethane acrylate oligomer obtained in Preparation Example 1, 0.1% cell opener (Dow Chemical Voranol CP1421), 3% foaming agent (azobisisobutyronitrile), 5% photoinitiator, 0.5% hydrophobic additive (methacryloyloxypropylheptaisobutyl cage polysilsesquioxane), and 5% filler (hydrophobic fumed silica Aerosil R202).

[0064] The aforementioned photoinitiator is a mixture of 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, with a mass ratio of 3:1.

[0065] The preparation method includes the following steps:

[0066] (1) The acrylate monomer, the polyurethane acrylate oligomer prepared in Example 1 and the pore-opening agent are mixed and stirred to disperse evenly to obtain a mixed solution.

[0067] (2) Add the foaming agent, photoinitiator, hydrophobic additive and filler to the mixed solution in step (1) and stir and disperse until the mixture is uniform and there are no insoluble particles, to obtain the waterproof and breathable adhesive.

[0068] Example 6

[0069] This embodiment provides a waterproof and breathable adhesive and its preparation method. The difference between this embodiment and Embodiment 1 is that, while keeping the photoinitiator content unchanged, all types of photoinitiators are replaced with 2-isopropylthioxanthrone. Other raw materials, dosages, and preparation methods are the same as in Embodiment 1.

[0070] Example 7

[0071] This embodiment provides a waterproof and breathable adhesive and its preparation method. The difference between this embodiment and Embodiment 1 is that, while keeping the photoinitiator content unchanged, the photoinitiator is only 1-hydroxycyclohexylphenyl ketone. Other raw materials, dosages, and preparation methods are the same as in Embodiment 1.

[0072] Example 8

[0073] This embodiment provides a waterproof and breathable adhesive and its preparation method. The difference between this embodiment and Embodiment 1 is that the mass percentage of the foaming agent is 0.5%, the mass percentage of the acrylate monomer is 37%, and the other raw materials, dosages, and preparation methods are the same as in Embodiment 1.

[0074] Example 9

[0075] This embodiment provides a waterproof and breathable adhesive and its preparation method. The difference between this embodiment and Embodiment 1 is that the mass percentage of the foaming agent is 4%, the mass percentage of the acrylate monomer is 33.5%, and the other raw materials, dosages, and preparation methods are the same as in Embodiment 1.

[0076] Example 10

[0077] This embodiment provides a waterproof and breathable adhesive and its preparation method. The difference between this embodiment and Example 3 is that the mass percentage of the photoinitiator is 1%, the mass percentage of the acrylate monomer is 49%, and the other raw materials, dosages, and preparation methods are the same as in Example 3.

[0078] Example 11

[0079] This embodiment provides a waterproof and breathable adhesive and its preparation method. The difference between this embodiment and Embodiment 3 is that the mass percentage of the photoinitiator is 6%, the mass percentage of the acrylate monomer is 44%, and the other raw materials, dosages, and preparation methods are the same as in Embodiment 3.

[0080] Comparative Example 1

[0081] This comparative example provides a waterproof and breathable adhesive and its preparation method. The difference between this example and Example 1 is that no pore-opening agent is added, the mass of the acrylate monomer is 35.5%, and the other raw materials, dosages, and preparation methods are the same as in Example 1.

[0082] Comparative Example 2

[0083] This comparative example provides a waterproof and breathable adhesive and its preparation method. The difference between this example and Example 1 is that no hydrophobic additives are added, the mass of acrylate monomers is 37%, and the other raw materials, dosages, and preparation methods are the same as in Example 1.

[0084] Comparative Example 3

[0085] This comparative example provides a waterproof and breathable adhesive and its preparation method. The waterproof and breathable adhesive is a silicone adhesive, and its preparation method is as follows:

[0086] (1) Mix 100 parts of α,ω-dihydroxy polydimethylsiloxane with a viscosity of 3000 cps, 30 parts of dimethyl silicone oil with a viscosity of 500 cps, and 100 parts of modified CaCO3 (Shenba SF-5000) and put them into a planetary mixer for stirring. Mix for 3 hours under the conditions of temperature of 130℃ and vacuum degree of -0.098MPa. Then introduce N2 to release the vacuum and obtain the base material.

[0087] (2) Add 12 parts of methyltrimethoxysilane to the base material, evacuate the vacuum, and mix under vacuum conditions of -0.098MPa and 50℃ for 40 min; then introduce N2 to release the vacuum.

[0088] (3) Add 1.6 parts of vinyltrimethoxysilane and 0.3 parts of dibutyltin dilaurate to the material obtained in step (2), evacuate, mix for 30 minutes under vacuum conditions of -0.098MPa and temperature of 60℃, introduce N2 to release the vacuum, and package and seal the prepared silicone sealant according to the packaging specifications.

[0089] The waterproof and breathable adhesives provided in the examples and comparative examples were subjected to the following performance tests.

[0090] (1) Curing time: at an ultraviolet light wavelength of 365nm and a light intensity of 1000mW / cm². 2 Curing was carried out, and the time required for complete curing was tested.

[0091] (2) Waterproof test: The waterproof and breathable adhesive provided in the examples and comparative examples is used to seal the vent hole, cure it under ultraviolet light, and then centrifuge and wash it with water. Observe whether water enters the vent hole. If large water droplets are observed on the AR sheet inside the camera module, it is considered as water ingress. If a layer of water mist is observed on the AR sheet inside the camera module, it is considered as a small amount of water ingress. If the AR sheet inside the camera module is clean and there are no water droplets or mist, it is considered as no water ingress.

[0092] (3) Breathability test: The waterproof and breathable adhesive provided in the examples and comparative examples is used to seal the air vents. After curing under ultraviolet light, it is baked at 85°C. Observe whether the waterproof and breathable adhesive falls from the air vents. If it falls, it is considered to burst. If it comes out from the air vents but does not fall, it is considered to burst slightly. If it does not come out, it is considered to be normal.

[0093] The test results are shown in Table 1.

[0094] Table 1

[0095]

[0096]

[0097] According to the test results in Table 1, the waterproof and breathable adhesive provided by the present invention has a short curing time, can foam smoothly, and has uniform cell structure, resulting in good waterproof and breathable effects.

[0098] Compared with Example 1, Examples 6 and 7 show that using a single photoinitiator results in a longer curing time for the waterproof and breathable adhesive, and slight bursting occurs. This is because the low initiation efficiency of a single initiator leads to slow curing of the waterproof and breathable adhesive, making it difficult to form a porous structure and reducing its breathability. This demonstrates that using a mixture of 1-hydroxycyclohexylphenyl ketone and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide as an initiator produces a waterproof and breathable adhesive with better performance.

[0099] Compared with Example 1, it can be seen that if the content of foaming agent is too low (Example 8), the waterproof and breathable adhesive will not foam completely, the pores will not be connected, which is not conducive to the formation of a through-pore structure, and the breathability of the waterproof and breathable adhesive will be poor. If the content of foaming agent is too high (Example 9), the waterproof and breathable adhesive will foam excessively, the formed pores will be too large, the capillary effect will be reduced, water will enter during centrifugal washing, and the waterproof effect will be poor. This proves that the waterproof and breathable adhesive made with a specific mass fraction of foaming agent has better performance.

[0100] Compared with Example 3, it can be seen that if the content of photoinitiator is too low (Example 10), the curing speed will be slower after UV irradiation, less heat will be released, the decomposition of the foaming agent will be delayed and incomplete, the waterproof and breathable adhesive will not foam completely, and it will fail to form a through-hole or honeycomb structure. Slight bursting will occur when baking at 85°C, and the breathability will be worse. If the content of photoinitiator is too high (Example 11), the curing speed will be too fast, a large amount of heat will be released, the waterproof and breathable adhesive will foam excessively, the pore structure will be too large, water droplets will easily enter the module through the adhesive layer, and the waterproof effect will be worse. This proves that the waterproof and breathable adhesive made with a specific mass fraction of photoinitiator has better performance.

[0101] Comparing Comparative Example 1 with Example 1, it can be seen that if no opening agent is added, the waterproof and breathable adhesive will foam unevenly, the bubbles will not break smoothly, and the open pores and honeycomb structure will not be formed. The adhesive will burst when baked at 85°C, and the breathability will deteriorate.

[0102] Comparing Comparative Example 2 with Example 1, it can be seen that without the addition of hydrophobic additives, the waterproof and breathable adhesive lacks the hydrophobic modification of hydrophobic additives. A small amount of water enters during centrifugal washing, and the adhesive bursts when baked at 85°C, which makes the waterproof and breathable adhesive performance worse.

[0103] Compared with Example 1, it can be seen that although the silicone sealant (Comparative Example 3) has a better waterproof effect, it has a long curing time, causes the sealant to burst when baked at 85°C, and has poor air permeability.

[0104] The applicant declares that this invention illustrates a waterproof and breathable adhesive, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials in the product, addition of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A waterproof and breathable adhesive, characterized in that, The raw materials for preparing the waterproof and breathable adhesive include the following components by mass percentage: 25-55% acrylate monomers, 30-62% polyurethane acrylate oligomers, 0.1-1% cell opener, 1-3% foaming agent, 3-5% photoinitiator, 0.5-2% hydrophobic additives, and 1-5% filler; The photoinitiator is a mixture of 1-hydroxycyclohexylphenyl ketone and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide; The hydrophobic additive includes cage-type polysilsesquioxane.

2. The waterproof and breathable adhesive according to claim 1, characterized in that, The acrylate monomers include any one or a combination of at least two of the following: isobornyl acrylate, hydroxyethyl methacrylate, tetrahydrofuran acrylate, tetrahydrofuran methacrylate, ethoxytetrahydrofuran acrylate, trimethylolcyclohexyl acrylate, cyclotrimethylolpropane methyl acetal acrylate, dodecyl acrylate, or isodecanyl acrylate.

3. The waterproof and breathable adhesive according to claim 1, characterized in that, The polyurethane acrylate oligomers include aliphatic polyurethane acrylate oligomers.

4. The waterproof and breathable adhesive according to claim 1, characterized in that, The pore-opening agent includes any one or a combination of at least two of the following: Voranol CP1421 from Dow Chemical, Desmophen 41WB01 from Bayer, or DC-2525 from Dow Corning.

5. The waterproof and breathable adhesive according to claim 1, characterized in that, The foaming agent includes azobisisobutyronitrile.

6. The waterproof and breathable adhesive according to claim 1, characterized in that, The cage-type polysilsesquioxane includes methacryloyloxypropyl heptaisobutyl cage-type polysilsesquioxane.

7. The waterproof and breathable adhesive according to claim 1, characterized in that, The filler comprises hydrophobic fumed silica.

8. A method for preparing a waterproof and breathable adhesive as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: mixing acrylate monomers, polyurethane acrylate oligomers, cell openers, foaming agents, photoinitiators, hydrophobic additives and fillers to obtain the waterproof and breathable adhesive.

9. The preparation method according to claim 8, characterized in that, The mixing method is as follows: (1) Mix acrylate monomers, polyurethane acrylate oligomers and pore-opening agents to obtain a mixed solution; (2) Mix the mixed solution described in step (1) with the foaming agent, photoinitiator, hydrophobic additive and filler.

10. The application of the waterproof and breathable adhesive according to any one of claims 1-7 in the camera module manufacturing process.

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