A photocured leakproof material, a leakproof method using the material, and applications thereof

Abstract

The present application relates to a photocurable leakproof material, a leakproof method using the same and applications thereof, wherein the photocurable leakproof material comprises 60-80 wt% of a methacrylic aliphatic polyurethane oligomer, 10-34 wt% of an acrylate monomer, 4-8 wt% of a photoinitiator, 1-8 wt% of a micron hydrocarbon wax and 1-4 wt% of a filler, based on the total weight of the photocurable leakproof material. The photocurable leakproof material of the present application can be coated on part of the surface of a fastener to form a coating layer, and after the coating layer is irradiated with UVA and UVC, the coating layer is cured and forms a leakproof layer, which is then locked to the counterpart of the fastener, thereby achieving good leakproof effect.

Description

Technical Field

[0001] This invention relates to a light-curable leak-proof material, a leak-proof method using the light-curable leak-proof material, and its application. Background Technology

[0002] In recent years, with the development of various electronic products, the need to keep the components in these products dry and free from moisture or dust has been increasing. Therefore, the leak-proof function of fasteners used to assemble different components has become increasingly important.

[0003] Traditional screws are designed to prevent leakage by first fitting a rubber washer onto the threaded part of the screw before tightening it to the locking mechanism. The rubber washer, located between the screw seat and the locking mechanism, achieves the purpose of preventing leakage. However, this type of traditional screw requires additional time and manpower to install the rubber washer during assembly. Besides affecting production capacity and efficiency, after tightening, the screw head protrudes due to the rubber washer underneath, thus impacting design space and appearance.

[0004] Subsequently, various sectors began to replace rubber washers with anti-leakage adhesive. First, an anti-leakage adhesive layer is pre-applied to the screw seat surface, then cured by high-temperature heating between the screw seat surface and the locking mechanism. This allows the screw seat surface to adhere to the locking mechanism, achieving leak prevention. However, this type of anti-leakage adhesive requires high-temperature curing, which can cause discoloration and yellowing of the metal surface of the screw, and may even damage the metal plating, leading to rust, corrosion, or bulging. This not only affects the appearance but may also cause machine damage or reduced sealing of parts due to rust, corrosion, or bulging. The anti-leakage adhesive must withstand a certain screwing torque during fastening, and its hardness and deformation must meet the requirements for gap filling and leak prevention. However, current commercially available products do not consider the operating temperature requirements, and the anti-leakage adhesive applied to fasteners often cracks or falls off during fastening. Furthermore, traditional anti-leakage adhesive still has a slightly sticky feel after curing. When several screws are stacked together, slight adhesion may occur between them, which is detrimental to automated feeding production lines. Overall, there is still room for improvement in commercially available leak-proof adhesives.

[0005] At present, it is still necessary to develop a leak-proof material that has good deformation under certain screwing torque conditions, while also having certain hardness, low stickiness and low roughness, and can withstand certain working temperatures. Summary of the Invention

[0006] In view of the aforementioned shortcomings of the prior art, one object of the present invention is to provide a photocurable leak-proof material suitable for fasteners, wherein the leak-proof layer formed by the material has good deformation capacity, while also possessing a certain degree of hardness, low adhesion and low abrasion, and the ability to withstand a certain operating temperature. This photocurable leak-proof material does not require high-temperature (e.g., 130°C to 180°C) thermal curing as with traditional leak-proof adhesives; it can be coated at low temperatures and then photocured, thus avoiding damage to the metal plating on the screw surface or causing discoloration, and further improving both appearance and safety.

[0007] Another object of the present invention is to provide a leak-proof method, which achieves a good leak-proof effect by coating the aforementioned light-curing leak-proof material onto a fastener and then performing light curing.

[0008] Another object of the present invention is to provide a leak-proof fastener comprising a leak-proof layer formed by the aforementioned light-cured leak-proof material, which not only achieves a good leak-proof effect, but also has low adhesion and low stickiness, making it applicable to automated feeding production lines.

[0009] To achieve the above objectives, the present invention provides a photocurable leak-proof material comprising: 60% to 80% by weight of aliphatic polyurethane oligomer of methacrylate, 10% to 34% by weight of acrylate monomer, 4% to 8% by weight of photoinitiator, 1% to 8% by weight of micronized hydrocarbon wax, and 1% to 4% by weight of filler, based on the total weight of the photocurable leak-proof material.

[0010] The present invention also provides a leak-proof method, which includes:

[0011] Step 1, Provide a fastener;

[0012] Step 2: Before fastening the fastener to its corresponding locking member, apply the light-curing leak-proof material as described above to a portion of the fastener's surface to form a coating layer, wherein the portion of the fastener's surface is intended to contact the locking member; and

[0013] Step 3: Simultaneously expose the coating layer to UVA and UVC light for 3 to 60 seconds to cure the coating layer and form a leak-proof layer, resulting in a leak-proof fastener. The UVA irradiation intensity is 500 milliwatts per square centimeter (mW / cm²). 2 The UVC irradiation intensity is above 30 mW / cm². 2 In summary, when the leak-proof fastener is fastened to its corresponding locking member, the leak-proof layer will come into contact with the locking member.

[0014] The present invention also provides a leak-proof fastener, comprising:

[0015] A fastener; and

[0016] A leak-proof layer, wherein the leak-proof layer is located on a portion of the surface of the fastener and is obtained by photocuring the photocurable leak-proof material as described above, wherein the leak-proof layer will come into contact with the corresponding locking member when the leak-proof fastener is fastened to its corresponding locking member.

[0017] In some specific embodiments, the aliphatic polyurethane oligomer of methacrylate may be a block copolymer of α-hydro-ω-hydroxy-poly(oxy-1,4-butanediyl), 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, and 2-hydroxyethyl methacrylate, or a copolymer or blend thereof, but is not limited thereto. In this invention, the aliphatic polyurethane oligomer of methacrylate is used to provide the main structure of the leak-proof layer of this invention. In some specific embodiments, the content of the aliphatic polyurethane oligomer of methacrylate, based on the total weight of the photocurable leak-proof material, may be 62% by weight, 65% by weight, 68% by weight, 70% by weight, 72% by weight, 75% by weight, or 78% by weight. Preferably, the content of the methacrylic aliphatic polyurethane oligomer is 70% to 80% by weight or 70% to 75% by weight, based on the total weight of the light-cured leak-proof material.

[0018] In some specific embodiments, the acrylate monomer comprises hydroxyethyl acrylate, hydroxymethyl acrylate, isobornyl acrylate, aryloyl morpholine, acrylic acid, dimethylacetoacetamide, 2-ethylhexyl acrylate, methacrylic acid, dimethacrylamide, dimethylallylamine, or combinations thereof. In this invention, the acrylate monomer system is used to adjust the viscosity of the photocurable leak-proof material of this invention. In some specific embodiments, the content of the acrylate monomer, based on the total weight of the photocurable leak-proof material, may be 12% by weight, 15% by weight, 18% by weight, 20% by weight, 22% by weight, 25% by weight, 28% by weight, 30% by weight, 32% by weight, or 34% by weight.

[0019] In this invention, photoinitiators known in the art can be used. In some specific embodiments, the photoinitiator is an acetophenone-based photoinitiator, such as acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylamineacetophenone, dichloroacetophenone, trichloroacetophenone, and p-tert-butylacetophenone, 2,2-dimethoxy-2-phenylacetophenone, but not limited thereto. In this invention, the photoinitiator generates free radicals, causing the methacrylate aliphatic polyurethane oligomer to undergo a crosslinking reaction with the acrylate monomer. In some specific embodiments, the content of the photoinitiator may be 5% by weight, 6% by weight, or 7% by weight, based on the total weight of the photocurable leak-proof material.

[0020] In some specific embodiments, the micron-sized hydrocarbon wax is a polypropylene wax. In some specific embodiments, the polypropylene wax is a polypropylene wax with a surface carboxylate-modified structure. In some specific embodiments, the micron-sized hydrocarbon wax is a particulate wax with a particle size of 30 micrometers (μm) to 50 μm. In this invention, a relatively lightweight micron-sized hydrocarbon wax is used, for example, with a specific gravity of 0.90 g / cm³. 3 Up to 1.0 g / cm 3 Or at 0.95 g / cm 3 Up to 0.99 g / cm 3 Or at 0.97 g / cm 3 Up to 0.99 g / cm 3The micron-sized hydrocarbon wax is used within a certain range. In some specific embodiments, a micron-sized hydrocarbon wax with a high melting point is used, for example, a micron-sized hydrocarbon wax with a melting point in the range of 110°C to 190°C, or 120°C to 180°C, or 130°C to 170°C. In this invention, the micron-sized hydrocarbon wax has good compatibility with the methacrylate aliphatic polyurethane oligomer and the acrylate monomer; and it can provide a lubricating effect, reducing the friction between the seat surface of the fastener and the contact surface of the locking element during fastening, controlling the seat surface friction coefficient to 0.08 to 0.35, thereby reducing the shear force on the leak-proof layer and avoiding cracking or wear; in addition, the micron-sized hydrocarbon wax has a low specific gravity, and after coating the UV-cured leak-proof material, the micron-sized hydrocarbon wax will float on the coating surface of the UV-cured leak-proof material, thus forming micro-bumps after UV curing, thereby improving the slightly sticky feel of traditional leak-proof adhesives after curing. In the fastener manufacturing process, several fasteners may stack or touch each other (such as when a package contains thousands of screws). In this case, the fasteners may contact each other at various angles. The slightly tacky feel of traditional anti-leakage adhesive after curing may cause these fasteners to slightly stick together, creating a false sense of adhesion, which is detrimental to automated production lines. In some specific embodiments, the content of the micronized hydrocarbon wax, based on the total weight of the photocurable anti-leakage material, can be 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, or 7% by weight.

[0021] In some specific embodiments, the filler is silica. In some specific embodiments, the silica is fumed silica. In this invention, the filler can improve the abrasion resistance and shear resistance of the leak-proof layer; in addition, the filler can also increase the physical cross-linking points of the photocurable leak-proof material after curing, so that when subjected to external force, the force can be dissipated in different directions, which helps to improve the mechanical strength of the cured leak-proof layer colloid and prevents cracking under certain screwing torque conditions. In some specific embodiments, the content of the filler can be 1.5% by weight, 2% by weight, 2.5% by weight, 3% by weight, or 3.5% by weight, based on the total weight of the photocurable leak-proof material.

[0022] In some specific embodiments, the photocurable leak-proof material further comprises 1% to 5% by weight of additives, wherein the additives may be selected from colorants, silanes, thixotropic agents, crosslinking agents, or combinations thereof. In this invention, the addition of colorants is primarily for identification or decorative purposes. In this invention, the addition of thixotropic agents is used to reduce the flowability of the photocurable leak-proof material, aiding in shaping and preventing sagging before curing. In this invention, the addition of silanes is used to reduce the surface tension of the cured photocurable leak-proof material, thereby improving anti-sticking properties and reducing hygroscopicity. In this invention, the addition of crosslinking agents is used to enhance the curing of the photocurable leak-proof material.

[0023] In some specific embodiments, the content of the additive may be 2% by weight, 3% by weight, or 4% by weight, based on the total weight of the photocurable leak-proof material.

[0024] In this invention, the photocurable leak-proof material is coated on a portion of the fastener's surface to form a coating layer, wherein the portion of the fastener's surface will contact the locking components. In some embodiments, the fastener is a nail-shaped fastener comprising a head and a rod portion, and the photocurable leak-proof material is coated on an annular seat surface below the head of the nail-shaped body. In some embodiments, the photocurable leak-proof material is coated on at least a portion of the annular seat surface below the head of the nail-shaped body and its rod portion. In some embodiments, the photocurable leak-proof material is coated on at least a portion of the annular seat surface below the head of the nail-shaped body and its rod portion connected to the annular seat surface; that is, the leak-proof layer extends a certain height from the seat surface towards the other end of the rod portion to ensure that the area coated with the photocurable leak-proof material completely covers the main portion of the fastener that contacts the locking components. In some embodiments, the nail-shaped body is a screw, a pull cap, a pop rivet, or other similar object. In this invention, the nail-shaped body (such as a screw) includes a head and a rod, and the seat surface refers to the contact surface on the bottom side of its head that contacts the corresponding locking element, and the seat surface is annular.

[0025] In some specific embodiments, step 2 includes:

[0026] Step 2-1: Heat the photocurable leak-proof material as described above at a preheating temperature to form a flowable photocurable leak-proof material; and

[0027] Step 2-2: Before fastening the fastener to a pair of locking members, apply the liquid-state light-cured leak-proof material to a portion of the fastener surface to form a coating layer.

[0028] In some embodiments, a pretreatment step may be further included between step 1 and step 2 to pretreat the surface of the fastener. In some embodiments, this pretreatment step pretreats a portion of the fastener's surface to which the UV-cured anti-leakage material is to be coated. In this invention, the aforementioned pretreatment is used to improve the unfavorable adhesion conditions on the fastener surface caused by rust prevention treatment. In some embodiments, the aforementioned pretreatment includes applying a primer.

[0029] In some specific embodiments, the UVA irradiation intensity used in step 3 is 510 mW / cm². 2 The above, or 520mW / cm 2 The above is true. The UVC irradiation intensity is 40 mW / cm². 2 The above, or 50 mW / cm2 above.

[0030] In some specific embodiments, the irradiation time for UVA and UVC used in step 3 is 3 to 60 seconds. In some specific embodiments, the irradiation time can be determined according to different coating thicknesses, ranging from 3 to 60 seconds, and can be 3 to 10 seconds, 10 to 20 seconds, 20 to 30 seconds, 30 to 40 seconds, 40 to 50 seconds, or 50 to 60 seconds.

[0031] In some specific embodiments, the preheating temperature ranges from 25°C to 40°C, or from 30°C to 35°C. In this invention, heating the photocurable leak-proof material at a preheating temperature is to avoid excessively high viscosity of the photocurable leak-proof material due to excessively low ambient temperatures (such as preparing the leak-proof fasteners of this invention at around 0°C), making it difficult to flow. In this invention, the heating method for the photocurable leak-proof material can be infrared (IR) heating, hot air heating, high-frequency heating, etc., but is not limited to these methods.

[0032] In this invention, the photocuring process uses two ultraviolet light wavelengths of different wavelengths for simultaneous irradiation. These ultraviolet light wavelengths can be UVA (Ultraviolet A) and UVC (Ultraviolet C). Shorter wavelengths of ultraviolet light have higher energy, which is more conducive to rapid surface curing; while higher wavelengths of ultraviolet light have better penetration, which is more conducive to deep curing. Traditional photocuring uses an exposure wavelength of 365 nm. The photocurable leak-proof material of this invention is simultaneously exposed to two different wavelengths of ultraviolet light, resulting in a more complete photocured leak-proof layer after complete curing.

[0033] In this invention, the wavelengths of UVA and UVC depend on the effective wavelength band of the photoinitiator. Generally, a photoinitiator has 2 to 3 suitable effective wavelength bands. After receiving light of these wavelengths, the photoinitiator will initiate the photocuring process.

[0034] In some embodiments, the UVC wavelength is from 220 nanometers (nm) to 280 nm, which can cure the surface of the leak-proof layer. In some embodiments, the absorption peak wavelength of the photoinitiator can be from 230 nm to 270 nm, or from 240 nm to 260 nm, or from 250 nm to 260 nm.

[0035] In some specific embodiments, the wavelength of UVA is 300 nm to 400 nm, which allows for deep curing of the leak-proof layer. In some specific embodiments, the absorption peak wavelength of the photoinitiator may be 310 nm to 390 nm, or 320 nm to 380 nm, or 330 nm to 370 nm, or 340 nm to 360 nm, or 350 nm to 360 nm.

[0036] In some specific embodiments, the coating in step 2 can be performed manually or using an artificial intelligence dispensing mechanism. In some specific embodiments, if the coating in step 2 is performed using an artificial intelligence dispensing mechanism, the coating can then be conveyed by a conveyor to a UV lamp with UVA and UVC light, followed by photocuring in step 3 to form a leak-proof layer; subsequently, it can be conveyed again by a conveyor to a screening area for automatic screening using a charge-coupled device (CCD) lens, completing the preparation steps on the same production line or machine.

[0037] In some specific embodiments, the thickness of the leak-proof layer is from 30 μm to 200 μm. In this invention, when the thickness of the photocurable leak-proof material is increased, the light energy needs to be appropriately increased, the light power increased, or the light exposure time lengthened.

[0038] In some specific embodiments, the leak-proof layer has good leak-proof performance, reaching an IPX7 rating (maintaining waterproof performance for 30 minutes in 1 meter of water). In this invention, the leak-proof performance is determined by testing according to IEC 60529 standards.

[0039] In some specific embodiments, the Shore A hardness of the leak-proof layer is 55 to 65, or 60 to 65. In this invention, the Shore A hardness is determined according to the ASTM D2240 standard method.

[0040] In some specific embodiments, the deformation of the leak-proof layer is higher than 60%, or higher than 65%, or higher than 70%. In this invention, the deformation is determined according to the Dongri Torque Test Specification.

[0041] In some specific embodiments, the leak-proof layer can withstand operating temperatures ranging from -40°C to 120°C, or from -35°C to 110°C, or from -30°C to 100°C, or from -20°C to 90°C, or from -10°C to 80°C, or from 0°C to 70°C. In this invention, the term "operating temperature that the leak-proof layer can withstand" means that the leak-proof layer will not crack or detach due to compression at this temperature. The fasteners of this invention can be applied to products that generate heat during prolonged operation, such as mobile phones, tablets, computers, automotive electronic interior parts, and center console panels. These products may also be transported to colder regions, thus requiring a wide operating temperature range. In this invention, the operating temperature is determined by testing the glass transfer temperature using a differential scanning calorimeter (DSC).

[0042] In some specific embodiments, the coefficient of friction of the seat surface of the leak-proof layer is 0.08 to 0.35, or 0.1 to 0.3, or 0.15 to 0.25, or 0.15 to 0.2. In this invention, the coefficient of friction of the seat surface of the leak-proof layer within the aforementioned range exhibits low friction. In this invention, the coefficient of friction of the seat surface is determined by means of a coefficient of friction tester.

[0043] In some specific embodiments, the leak-proof layer has low adhesion. In this invention, adhesion is tested using the following method: 100 screws coated with the aforementioned UV-cured leak-proof material of this invention are placed in a polyethylene (PE) can with a diameter of 64 mm and a height of 120 mm, and vibrated at a frequency of 1780 cpm (cycles per minute) for 3 minutes, after which the screw adhesion rate is calculated. In some specific embodiments, the number of screws coated with the UV-cured leak-proof material of this invention that adhered after the aforementioned test was 0.

[0044] The photocurable leak-proof material of the present invention can be used to make a leak-proof layer. The photocurable leak-proof layer has good Shore A hardness, deformation and operating temperature range, and can be more widely used in electronic products such as mobile phones, tablets, computers, automotive electronic interior parts and center console panels. Attached Figure Description

[0045] Figure 1 A schematic diagram showing the formation of a coating layer by applying the photocurable leak-proof material of the present invention to fasteners.

[0046] Figure 2 This is a schematic diagram of a fastener having a coating layer made of the photocurable leak-proof material of the present invention photocured to form a leak-proof layer, which is then attached to a locking component. Detailed Implementation

[0047] The objectives, advantages, and technical features of the present invention will become apparent from the following detailed description of the embodiments and accompanying drawings.

[0048] Preparation of the photocurable leak-proof material of the present invention

[0049] raw material:

[0050] Aliphatic polyurethane oligomers of methacrylate: Aliphatic polyurethane oligomers of methacrylate using CAS No. 82339-26-2, namely, a block copolymer of α-hydro-ω-hydroxy-poly(oxy-1,4-butanediyl), 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, and 2-hydroxyethyl methacrylate (poly(oxy-1,4-butanediyl), alpha-hydro-omega-hydroxy-, polymer with 5-isocyanato-1-(isocyanatomethyl)-1,3,3-trimethylcyclohexane, 2-hydroxyethyl methacrylate-blocked).

[0051] Acrylate monomer: Isoborneol acrylate, CAS No. 5888-33-5.

[0052] Photoinitiator: 2,2-Dimethoxy-2-phenylacetophenone, CAS No. 24650-42-8.

[0053] Micron-sized hydrocarbon wax: Polypropylene wax with a particle size of 30 μm to 50 μm, which has been modified by carboxylation of the surface.

[0054] Filler: Fumed silica with CAS No. 112945-52-5.

[0055] The aforementioned raw materials were mixed at 25±3°C in the following proportions: 70% by weight of methacrylate aliphatic polyurethane oligomer, 20% by weight of acrylate monomer, 5% by weight of photoinitiator, 3% by weight of micronized hydrocarbon wax and 2% by weight of filler, to obtain the photocurable leak-proof material of the present invention.

[0056] Preparation and testing of fasteners according to the present invention

[0057] First, the aforementioned photocurable leak-proof material is heated to a preheating temperature to become a fluid photocurable leak-proof material, which facilitates coating. The aforementioned preheating temperature ranges from 25°C to 40°C.

[0058] like Figure 1 and Figure 2As shown, a screw 1 is first provided, which includes a head 10 and a shank 20. The aforementioned liquid-state photocurable leak-proof material is coated on the annular seat surface below the head 10 and at least a portion of the shank 20 connected to the annular seat surface, with a thickness of 50 μm to 80 μm, forming a coating layer 11, thus obtaining the screw 1'.

[0059] For example Figure 2 As shown, simultaneously using ultraviolet A light (irradiation intensity of 500 mW / cm²) 2 The above power) and UVC (irradiation intensity of 30 mW / cm) 2 The coating layer 11 is exposed to light (at the above power) for 5 seconds, causing the coating layer 11 to begin photocuring and form a leak-proof layer 11', resulting in a leak-proof screw 1" after photocuring, which is the leak-proof fastener of the present invention. When the leak-proof screw 1" is fastened to its corresponding locking member 2, the leak-proof layer 11' will come into contact with the locking member 2.

[0060] The fasteners of this invention were then subjected to relevant tests:

[0061] The leak-proof effect of the leak-proof layer made of the aforementioned photocurable leak-proof material was tested according to IEC 60529 standard. This involved attaching screws coated with the aforementioned photocurable leak-proof material to a leak-proof fixture, placing it in an oven, heating it at different temperatures, removing it, cooling it, and then testing it. The photocurable leak-proof layer of this invention has a more complete structure and excellent water-resistant effect, reaching an IPX7 rating (maintaining a waterproof effect for 30 minutes in 1 meter of water).

[0062] The Shore hardness A of the leak-proof layer made from the photocurable leak-proof material of the present invention was tested according to the ASTM D2240 standard method. The Shore hardness A of the photocurable leak-proof layer of this invention is below 65, which indicates good hardness. If the Shore hardness A is higher than 65, the deformation is insufficient, the compressibility is poor, and the screw head will protrude too much after fastening, causing assembly interference.

[0063] The deformation of the leak-proof layer made from the photocurable leak-proof material of the present invention was measured using a Tohnichi torque wrench according to Tohnichi's torque test specifications. It was found that when using screws of different specifications (such as M8 to M4) with a screwing torque of 1T for fixing, the deformation of the photocurable leak-proof layer of this invention is higher than 60%, which can meet the requirements for gap filling and leak prevention. When the deformation is higher than 60%, the screw head will not cause assembly interference after tightening.

[0064] The operating temperature that the leak-proof layer made from the aforementioned photocurable leak-proof material of the present invention can withstand was determined by testing the glass transfer temperature using a microdifferential scanning calorimeter. The operating temperature of the photocurable leak-proof layer in this invention is -40°C to 120°C, exhibiting a good operating temperature range.

[0065] The coefficient of friction of the seat surface of the leak-proof layer made from the photocurable leak-proof material of the present invention was obtained by measuring the coefficient of friction. The coefficient of friction of the seat surface of the photocurable leak-proof layer in this case is 0.08 to 0.35, indicating low friction.

[0066] The adhesiveness of the leak-proof layer made from the photocurable leak-proof material of the present invention was tested according to the following method: 100 screws coated with the photocurable leak-proof material of the present invention were placed in a 250 ml PE container (64 mm in diameter and 120 mm in height). The PE container was then fixed on a NAS vibration machine fixture and vibrated at a frequency of 1780 cpm, causing the screws coated with the photocurable leak-proof material of the present invention to collide randomly for 3 minutes. After that, the screws were poured out, and the adhesion ratio of the screws was checked and counted. The photocurable leak-proof layer of this invention has low adhesiveness and does not stick after the above test, making it suitable for use in automated feeding production lines.

[0067] As can be seen from the above, the photocurable leak-proof material of the present invention, after being cured simultaneously using two ultraviolet lights of different wavelengths, UVA and UVC, results in a leak-proof layer with a Shore hardness A of less than 65. Furthermore, according to the Toyoda torque test specifications, when fixed with screws of different specifications (such as M8 to M4) at a screwing torque of 1T, the deformation of the leak-proof layer is higher than 60%, preventing assembly interference. In addition, the aforementioned leak-proof layer has a seat surface friction coefficient of 0.08 to 0.35, which reduces the friction between the seat surface of the fastener and the contact surface of the locking element during fastening. Its low slippage reduces the shear force on the leak-proof layer, preventing cracking or wear. Therefore, using the photocurable leak-proof material of the present invention to create a more complete leak-proof layer on fasteners can meet the requirements for gap filling and leak prevention. The aforementioned leak-proof layer can withstand a working temperature range of -40℃ to 120℃ and will not crack or fall off during fastening. Furthermore, the leak-proof layer made using the photocurable leak-proof material of the present invention has low adhesion, so the leak-proof fastener containing the leak-proof layer can be applied to automated feeding production lines and has a wider range of applications.

[0068] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A light-cured leak-proof material, characterized in that, It comprises, by weight of the total amount of the light-cured leak-proof material, 60% to 80% methacrylate aliphatic polyurethane oligomer, 10% to 34% acrylate monomer, 4% to 8% photoinitiator, 1% to 8% micronized hydrocarbon wax and 1% to 4% filler.

2. The photocurable leak-proof material as described in claim 1, characterized in that, The methacrylic aliphatic polyurethane oligomer is a block copolymer of α-hydro-ω-hydroxy-poly(oxy-1,4-butanediyl), 5-isocyanate-1-(isocyanate-methyl)-1,3,3-trimethylcyclohexane, and 2-hydroxyethyl methacrylate.

3. The photocurable leak-proof material as described in claim 1, characterized in that, The acrylate monomers include hydroxyethyl acrylate, hydroxymethyl acrylate, isoborneol acrylate, acryloyl morpholine, acrylic acid, dimethylacetoacetamide, 2-ethylhexyl acrylate, methacrylic acid, dimethylacrylamide, dimethylallylamine, or combinations thereof.

4. The photocurable leak-proof material as described in claim 1, characterized in that, The photoinitiator is an acetophenone-based photoinitiator.

5. The photocurable leak-proof material as described in claim 1, characterized in that, This micron-sized hydrocarbon wax is a carboxylated modified polypropylene wax.

6. The photocurable leak-proof material as described in claim 1, characterized in that, The filler is silicon dioxide.

7. The photocurable leak-proof material as described in any one of claims 1 to 6, characterized in that, It further comprises 1% to 5% by weight of additives, wherein the additives may be selected from pigments, silanes, thixotropic agents, crosslinking agents or combinations thereof.

8. A leak-proof method, characterized in that, Include: Step 1, provide a fastener; Step 2, before fastening the fastener to its corresponding locking member, applying the light-curing leak-proof material as described in any one of claims 1 to 7 to a portion of the surface of the fastener to form a coating layer, wherein the portion of the surface of the fastener is intended to contact the locking member. as well as Step 3: Simultaneously expose the coating layer to UVA and UVC light for 3 to 60 seconds to cure the coating layer and form a leak-proof layer, resulting in a leak-proof fastener. The UVA irradiation intensity is 500 mW / cm². 2 The UVC irradiation intensity is 30 mW / cm². 2 In summary, when the leak-proof fastener is fastened to its corresponding locking member, the leak-proof layer will come into contact with the locking member.

9. The leak-proof method as described in claim 8, characterized in that, Step 2 includes: Step 2-1: The photocurable leak-proof material as described in any one of claims 1 to 7 is heated at a preheating temperature to become a photocurable leak-proof material in a fluid state; as well as Step 2-2: Before fastening the fastener to a pair of locking members, apply the liquid-state light-cured leak-proof material to a portion of the fastener surface to form a coating layer.

10. A leak-proof fastener, characterized in that, Include: A fastener; and A leak-proof layer, wherein the leak-proof layer is located on a portion of the surface of the fastener and is obtained by photocuring the photocurable leak-proof material as described in any one of claims 1 to 7, wherein the leak-proof layer will contact the corresponding locking member when the leak-proof fastener is locked to its corresponding locking member.

Images