UV black adhesive with excellent sealing performance as well as preparation method and application of UV black adhesive

Abstract

The UV black adhesive with excellent sealing performance and the preparation method thereof aim at solving the problems that an existing sealing technology excessively depends on manual operation and is low in efficiency and poor in consistency, and silica gel with good toughness in the market is poor in adhesive performance, so that the sealing performance is limited, and polyurethane is resistant to aging. The UV black adhesive comprises modified organosilicone acrylate resin, a diluent, a photoinitiator and color paste; the modified organic silicon acrylate resin is prepared from a hydroxyl acrylate derivative, polyether glycol, double-terminal hydroxyl polysiloxane and alicyclic diisocyanate; the diluent comprises a diluent with high adhesive force and an acrylate reactive diluent. Through the synergistic effect of the modified organosilicone acrylate resin, the diluent, the photoinitiator, the color paste and the assistant, the prepared UV black adhesive has good air tightness, high toughness and high bonding strength, and can meet the application in the field of screen frames or controller shells.

Description

Technical Field

[0001] This invention relates to the field of UV black adhesive technology with excellent sealing performance, and more particularly to a UV black adhesive with excellent sealing performance and its preparation method. Background Technology

[0002] In the industrial manufacturing sector, sealing performance directly impacts equipment reliability and environmental adaptability. From sealing the housings and covers of industrial controllers to protecting display modules and bezels, and even waterproofing and dustproofing core components of new energy electric vehicles, sealing technology remains a crucial element in ensuring stable equipment operation. However, existing sealing solutions generally suffer from a trade-off between efficiency and performance, urgently requiring technological innovation and breakthroughs.

[0003] In traditional sealing processes, while sealing rings offer high dimensional accuracy, they rely on manual installation, resulting in poor consistency and incompatibility with automated production lines. Adhesive dispensing, while efficient, faces a trade-off between curing speed and performance—silicone-based CIPG and FIPG cure slowly, failing to meet the pace of modern production lines. UV curing technology, while achieving second-level curing, produces conventional products with insufficient toughness and poor sealing, unable to meet the demands of demanding operating conditions. This contradiction is particularly pronounced in the field of new energy electric vehicles.

[0004] It is worth noting that in fields such as IC encapsulation, electronic circuit reinforcement, and the connection of circuit boards and lead wires, dark-colored adhesives (such as black UV adhesives) can block light from damaging photosensitive devices. However, during the UV curing process, the surface pigment of high-chroma adhesives absorbs a large amount of light energy, resulting in a sharp reduction in the depth of light penetration. The curing reaction can only remain on the surface, making it difficult to meet the deep curing requirements of thick adhesive layers.

[0005] Therefore, developing a UV black adhesive that is fast-drying, can be deeply cured, has strong adhesive strength and good toughness, and has excellent sealing performance remains an urgent problem to be solved. Summary of the Invention

[0006] To address the issues of existing sealing technologies being overly reliant on manual operation, inefficient, and inconsistent, as well as the limited sealing performance of commercially available silicone with good toughness due to poor adhesion, and the toughness and aging resistance of polyurethane, this application provides a UV black adhesive with excellent sealing performance and its preparation method.

[0007] In a first aspect, the present invention provides a UV black adhesive with excellent sealing performance, characterized in that the UV black adhesive comprises a modified organosilicon acrylate resin, a diluent, a photoinitiator, and a color paste; The modified organosilicon acrylate resin is prepared from hydroxy acrylate derivatives, polyether diols, hydroxyl-terminated polysiloxanes, and alicyclic diisocyanates. The diluent includes a high-adhesion diluent and an acrylate reactive diluent; The high-adhesion diluent was prepared from isocyanate acrylic acid derivatives and triethylene glycol monomethyl ether; The photoinitiator includes one or more of the following: 2-benzyl-2-dimethylamino-4-morpholinyl phenylbutanone, 2-methyl-4-methylthio-2-morpholinyl phenylpropanone, 2-(4-methylbenzyl)-2-dimethylamino-4-morpholinyl phenylbutanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl phenyl ethyl hypophosphite, bis(2,4,6-trimethylbenzoyl)phenyl phosphorus oxide, 2-isopropylthioxanthrone, 2,4-diethylthioxanthrone, and 1-hydroxycyclohexylphenyl ketone; The color paste includes one or more of carbon black, titanium black, and aniline black, with a particle size not greater than 160 nm.

[0008] Preferably, the mass ratio of the high adhesion diluent to the acrylate reactive diluent is (1.3~2):1.

[0009] Preferably, the preparation method of the modified organosilicon acrylate resin includes the following steps: Step 1: Dehydrate the hydroxy acrylate derivative and the hydroxyl-terminated polysiloxane under vacuum at 90-110°C for 3-6 hours; Step 2: Mix the alicyclic diisocyanate with the first catalyst, the first polymerization inhibitor and the first antioxidant and heat to 60~80℃. Add the hydroxyl acrylate derivative dropwise. When the NCO value decreases to 50% of the initial value, intermediate product 1 is obtained. Step 3: Continue to add hydroxyl-terminated polysiloxane to intermediate product 1, heat to 70~90℃, and stop the reaction when the NCO content drops below 0.1% to prepare modified organosilicon acrylate resin.

[0010] Preferably, the molecular weight of the double-hydroxyl-terminated polysiloxane is 1000~2000 g / mol; The hydroxyl-containing acrylate derivatives include trimethylolpropane diacrylate; The alicyclic diisocyanate includes at least one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate.

[0011] Preferably, in the preparation method of the high-toughness photocurable resin, the molar ratio of alicyclic diisocyanate, hydroxyl-containing acrylate derivative and dihydroxyl-terminated polysiloxane is 1:(1~1.1):(1~1.1).

[0012] Preferably, the method for preparing the high-adhesion diluent includes the following steps: The triethylene glycol monomethyl ether was dehydrated; the isocyanate acrylic acid derivative, the second catalyst, the second polymerization inhibitor, and the second antioxidant were mixed and heated to 60-80°C, and the triethylene glycol monomethyl ether was added dropwise. The reaction was stopped when the NCO content decreased to below 0.1%, and a high-adhesion diluent was prepared.

[0013] Preferably, in the preparation method of the high adhesion diluent, the molar ratio of triethylene glycol monomethyl ether and isocyanate acrylic acid derivative is (1~1.1):1; The isocyanate acrylic derivatives include one or more of ethyl isocyanate, 1,1-di(acryloyloxymethyl)ethyl isocyanate, and ethyl isocyanate methacrylate. Preferably, the UV black adhesive with excellent sealing performance also includes additives; The UV black adhesive comprises the following raw materials in parts by weight: 45-65 parts of high-toughness light-curing resin, 35-45 parts of diluent, 1.5-4 parts of free radical photoinitiator, 0.02-0.05 parts of color paste, and 3-9 parts of additives.

[0014] Secondly, this application provides a method for preparing the UV black adhesive with excellent sealing performance as described above, characterized by comprising the following steps: Modified silicone acrylate resin, high adhesion diluent, acrylate reactive diluent, free radical photoinitiator and additives were mixed evenly under light-protected conditions according to the weight parts, and after vacuum degassing, the UV black glue with excellent sealing performance was obtained.

[0015] Thirdly, this application provides an application of the UV black adhesive with excellent sealing performance described above in sealing applications such as screen bezels or controller housings.

[0016] The beneficial effects of this invention are as follows: The modified organosilicon acrylate resin prepared in this application has good compatibility with the high adhesion diluent. The combination of the high adhesion diluent and the acrylic reactive diluent can better exert the performance of the modified organosilicon acrylate resin after curing. The modified organosilicon acrylate resin prepared in this application possesses a polysiloxane-polyurethane-acrylate ternary synergistic network constructed through molecular design. After modification, it acquires UV curing capability, resulting in a UV black adhesive with an elongation at break of 146%, providing high toughness while maintaining a tensile shear strength of 5.15 MPa. The improved toughness enhances sealing performance, allowing it to withstand harsh conditions of thermal shock from -40°C to 125°C for up to 1000 hours. It also exhibits strong adhesive properties. The reactive tetrafunctional acrylate can improve the curing speed, solving the problems of insufficient surface drying and insufficient curing depth of UV black adhesives.

[0017] The high-adhesion diluent prepared in this application has urethane and ether bonds, which increases adhesion and solves the problem of poor adhesion in organosilicon systems.

[0018] This application utilizes the synergistic effect of modified organosilicon acrylate resin, diluent, photoinitiator, color paste and additives to prepare a UV black adhesive with good airtightness, high toughness and high bonding strength, which can meet the application requirements of screen bezels or controller housings. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0021] In a first aspect, the present invention provides a UV black adhesive with excellent sealing performance, the UV black adhesive comprising a modified organosilicon acrylate resin, a diluent, a photoinitiator, and a color paste; The modified organosilicon acrylate resin is prepared from hydroxy acrylate derivatives, polyether diols, hydroxyl-terminated polysiloxanes, and alicyclic diisocyanates. The modified organosilicon acrylate resin prepared in this application possesses a polysiloxane-polyurethane-acrylate ternary synergistic network constructed through molecular design. After modification, it acquires UV curing capability, resulting in a UV black adhesive with an elongation at break of 146%, providing high toughness while maintaining a tensile shear strength of 5.15 MPa. The improved toughness enhances sealing performance, allowing it to withstand harsh conditions of thermal shock from -40°C to 125°C for up to 1000 hours. It also exhibits strong adhesive properties. The reactive tetrafunctional acrylate can improve the curing speed, solving the problems of insufficient surface drying and insufficient curing depth of UV black adhesives.

[0022] The diluent includes a high-adhesion diluent and an acrylate reactive diluent; The high-adhesion diluent prepared in this application has urethane and ether bonds, which increase adhesion and solve the problem of poor adhesion in organosilicon systems.

[0023] The high-adhesion diluent was prepared from isocyanate acrylic acid derivatives and triethylene glycol monomethyl ether; The photoinitiator includes one or more of the following: 2-benzyl-2-dimethylamino-4-morpholinyl phenylbutanone, 2-methyl-4-methylthio-2-morpholinyl phenylpropanone, 2-(4-methylbenzyl)-2-dimethylamino-4-morpholinyl phenylbutanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl phenyl ethyl hypophosphite, bis(2,4,6-trimethylbenzoyl)phenyl phosphorus oxide, 2-isopropylthioxanthrone, 2,4-diethylthioxanthrone, and 1-hydroxycyclohexylphenyl ketone; The color paste includes one or more of carbon black, titanium black, and aniline black, with a particle size not greater than 160 nm.

[0024] This application uses nanoscale color paste with a particle size of no more than 160nm, combined with a photoinitiator of a specific wavelength, to achieve a curing depth of 5.82mm, solving the problem that ultraviolet light cannot penetrate black colloids and meeting the sealing requirements of thick adhesive layer structures.

[0025] In some embodiments of the present invention, the acrylate reactive diluent includes at least one of the following: isoborneol acrylate, isoborneol methacrylate, isooctyl acrylate, isooctyl methacrylate, tetrahydrofuran acrylate, tetrahydrofuran methacrylate, trimethylolpropane triacrylate, 2-phenoxyethyl acrylate, ethoxylated trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, n-butyl acrylate, isodecanyl acrylate, laurate acrylate, cyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, 4-tert-butylcyclohexyl acrylate, dicyclopentenyl acrylate, and pentaerythritol tetraacrylate.

[0026] In some embodiments of the present invention, the mass ratio of the high adhesion diluent to the acrylate reactive diluent is (1.3~2):1.

[0027] In some embodiments of the present invention, the preparation method of the modified organosilicon acrylate resin includes the following steps: Step 1: Dehydrate the hydroxy acrylate derivative and the hydroxyl-terminated polysiloxane under vacuum at 90-110°C for 3-6 hours; Step 2: Mix the alicyclic diisocyanate with the first catalyst, the first polymerization inhibitor and the first antioxidant and heat to 60~80℃. Add the hydroxyl acrylate derivative dropwise. When the NCO value decreases to 50% of the initial value, intermediate product 1 is obtained. Step 3: Continue to add hydroxyl-terminated polysiloxane to intermediate product 1, heat to 70~90℃, and stop the reaction when the NCO content drops below 0.1% to prepare modified organosilicon acrylate resin.

[0028] In some embodiments of the present invention, the molecular weight of the double-hydroxyl-terminated polysiloxane is 1000~2000 g / mol; The hydroxyl-containing acrylate derivatives include trimethylolpropane diacrylate; The alicyclic diisocyanate includes at least one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate.

[0029] In some embodiments of the present invention, in the preparation method of the high-toughness photocurable resin, the molar ratio of alicyclic diisocyanate, hydroxyl-containing acrylate derivative and dihydroxyl-terminated polysiloxane is 1:(1~1.1):(1~1.1), such as 1:1:1, 1:1.02:1, 1:1.04:1.02, 1:1.06:1.08, 1:1:1.1, 1:1.1:1.1 or any value between them.

[0030] In some embodiments of the present invention, the method for preparing the high-adhesion diluent includes the following steps: The triethylene glycol monomethyl ether was dehydrated; the isocyanate acrylic acid derivative, the second catalyst, the second polymerization inhibitor, and the second antioxidant were mixed and heated to 60-80°C, and the triethylene glycol monomethyl ether was added dropwise. The reaction was stopped when the NCO content decreased to below 0.1%, and a high-adhesion diluent was prepared.

[0031] In some embodiments of the present invention, the first catalyst and the second catalyst are selected from one or more of organotin, organobismuth, organozinc, organocobalt and organic base catalysts.

[0032] In a preferred embodiment, both the first catalyst and the second catalyst are dibutyltin dilaurate. Dibutyltin dilaurate provides a high yield as a catalyst for the reaction of NCO and hydroxyl groups.

[0033] In some embodiments of the present invention, the first antioxidant and the second antioxidant are selected from one or more of 2,6-di-tert-butyl-4-methylphenol, 4,4'-thiobis(6-tert-butyl-3-methylphenol), pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, triphenyl phosphite, and trinonylphenyl phosphite.

[0034] In a preferred embodiment, both the first antioxidant and the second antioxidant are 2,6-di-tert-butyl-4-methylphenol.

[0035] In some embodiments of the present invention, the first polymerization inhibitor and the second polymerization inhibitor are each individually selected from one or more of p-hydroxyanisole, p-benzoquinone, hydroquinone, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, phenothiazine, and naphthoquinone.

[0036] In a preferred embodiment, both the first polymerization inhibitor and the second polymerization inhibitor are hydroquinone.

[0037] In some embodiments of the present invention, in the preparation method of the high adhesion diluent, the molar ratio of triethylene glycol monomethyl ether and isocyanate acrylic acid derivative is (1~1.1):1, such as 1:1, 1.02:1, 1.04:1, 1.06:1, 1.08:1, 1.1:1 or any value between them.

[0038] The isocyanate acrylic derivatives include one or more of ethyl isocyanate, 1,1-di(acryloyloxymethyl)ethyl isocyanate, and ethyl isocyanate methacrylate. In some embodiments of the present invention, the UV black adhesive with excellent sealing performance also includes additives; The UV black adhesive comprises the following raw materials in parts by weight: 45-65 parts of high-toughness photocurable resin, such as 45, 47, 50, 53, 55, 57, 60, 63, 65 parts or any value between them; 35-45 parts of diluent, such as 35, 36, 37, 38, 39, 40, 41, 42, 43, 45 parts or any value between them; 1.5-4 parts of free radical photoinitiator, such as 1.5, 2, 2.5, 3, 3.5, 4 parts or any value between them; 0.02-0.05 parts of color paste, such as 0.02, 0.03, 0.04, 0.05 parts or any value between them; and 3-9 parts of additives, such as 3, 4, 5, 6, 7, 8, 9 parts or any value between them.

[0039] In some embodiments of the present invention, the additives include one or more of fluorescent agents, color-changing powders, leveling agents, wetting agents, defoamers, silane coupling agents, antioxidants, antibacterial agents, flame retardants, and fillers.

[0040] In a second aspect, the present invention also provides a method for preparing the UV black adhesive with excellent sealing performance, characterized by comprising the following steps: Modified silicone acrylate resin, high adhesion diluent, acrylate reactive diluent, free radical photoinitiator and additives were mixed evenly under light-protected conditions according to the weight parts, and after vacuum degassing, the UV black glue with excellent sealing performance was obtained.

[0041] Thirdly, the present invention also provides an application of the UV black adhesive with excellent sealing performance in sealing such as screen bezels or controller housings.

[0042] The sources of raw materials used in the following preparation examples, embodiments, and comparative examples are as follows: Trimethylolpropane diacrylate, brand name CM1201, sourced from Guangdong Huiquan; isoflurone diisocyanate, brand name WANNATE® IPDI, sourced from Wanhua Chemical; dibutyltin dilaurate, brand name DBTDL, sourced from Maclean's; 2,6-di-tert-butyl-4-methylphenol, sourced from Shanghai Ronghe Chemical; hydroquinone, brand name HQ, sourced from Eastman Chemical Industries, USA; dihydroxyalkyl-terminated polydimethylsiloxane, brand name Silmer OH Di-10, sourced from Stey Chemicals, Canada; ethyl isocyanate, brand name Karenz AOI, sourced from Showa Denko, Japan; triethylene glycol monomethyl ether, sourced from Shandong Xuchen Chemical. Isoborneol acrylate, brand name EM 214, is sourced from Chang Hsing, Taiwan, China; laurate acrylate, brand name AgiSyn 2896, is sourced from Covestro; 2-benzyl-2-dimethylamino-4-morpholinophenylbutanone, brand name Omnirad 369, is sourced from IGM; bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, brand name JRCure-1109, is sourced from Jiuri New Materials; silane coupling agent, brand name Z6040, is sourced from Dow Corning, USA; titanium black, brand name 13M-C, is sourced from Mitsubishi, Japan; fumed silica, brand name H18, is sourced from Wacker Chemie, Germany.

[0043] The resin used in the comparative example is a high-performance polyester / polyether acrylate from Sartomer, brand name CN981NS, which has extremely high flexibility and adhesion; the high-adhesion diluent is a cyclotrimethylolpropane methyl acetal acrylate (CTFA) from IGM, brand name Photomer 4141, which has excellent wetting and adhesion.

[0044] Preparation Example 1 (1) Before use, trimethylolpropane diacrylate and dihydroxyalkyl-terminated polydimethylsiloxane were vacuum dehydrated and dried for 3 hours at 90°C.

[0045] (2) Under light-protected conditions, add 10g of isoflurane diisocyanate, 0.01g of catalyst DBTDL, 0.001g of di-tert-butyl-4-methylphenol and 0.001g of hydroquinone to a three-necked flask equipped with a thermometer. Add 16.7

[12] g of trimethylolpropane diacrylate at 70°C. When the NCO content in the reaction is 9.7%

[13] , add 22.5g

[14] dihydroxy-terminated polydimethylsiloxane (molecular weight 1000). Raise the temperature and maintain it at 80°C. Stop the reaction when the NCO content drops below 0.1%. Stop heating to obtain modified organosilicon acrylate resin.

[0046] Preparation Example 2 Under light-protected conditions, 10g of ethyl 2-isocyanate acrylate, 0.01g of catalyst, 0.001g of polymerization inhibitor and 0.001g of antioxidant were mixed and heated, and 12.7g

[15] g of dried triethylene glycol monomethyl ether was added dropwise. The NCO content was monitored to decrease to below 0.1%, and a high adhesion diluent was prepared.

[0047] Example 1 By weight, 55 parts of modified silicone acrylate resin, 40 parts of diluent (25 parts of high adhesion diluent, 10 parts of isoborneol acrylate, and 5 parts of lauric acid acrylate), 1.5 parts of photoinitiator (0.5 parts of 2-benzyl-2-dimethylamino-4-morpholinophenylbutanone and 1 part of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide), 0.03 parts of titanium black, 0.15 parts of hydroquinone, 6 parts of fumed silica, and 0.7 parts of silane coupling agent were mixed evenly under light-protected conditions and vacuum degassed to obtain the UV black adhesive with excellent sealing performance.

[0048] Example 2 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 46 parts of modified organosilicon acrylate resin are added.

[0049] Example 3 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 51 parts of modified organosilicon acrylate resin are added.

[0050] Example 4 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 60 parts of modified organosilicon acrylate resin are added.

[0051] Example 5 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 64 parts of modified organosilicon acrylate resin are added.

[0052] Example 6 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 68 parts of modified organosilicon acrylate resin are added.

[0053] Example 7 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 42 parts of modified organosilicon acrylate resin are added.

[0054] Example 8 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 35 parts of diluent (20 parts of high adhesion diluent, 10 parts of isoborneol acrylate, and 5 parts of laurate acrylate) are added.

[0055] Example 9 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 45 parts of diluent (30 parts of high adhesion diluent, 10 parts of isoborneol acrylate, and 5 parts of laurate acrylate) are added.

[0056] Example 10 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 48 parts of diluent (33 parts of high adhesion diluent, 10 parts of isoborneol acrylate, and 5 parts of laurate acrylate) are added.

[0057] Example 11 Most of the steps in this embodiment are the same as those in Embodiment 1, except that 32 parts of diluent (17 parts of high adhesion diluent, 10 parts of isoborneol acrylate, and 5 parts of laurate acrylate) are added.

[0058] Comparative Example 1 By weight, 55 parts of polycarbonate-type polyurethane acrylate, 40 parts of diluent (25 parts of cyclotrimethylolpropane methyl acetal acrylate, 10 parts of isoborneol acrylate, 5 parts of laurate acrylate), 1.5 parts of photoinitiator (0.5 parts of 2-benzyl-2-dimethylamino-4-morpholinophenyl phenethyl ketone and 1 part of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide), 0.03 parts of titanium black, 0.15 parts of hydroquinone, 6 parts of fumed silica and 0.7 parts of silane coupling agent were mixed evenly under light-protected conditions, and after vacuum degassing, UV black glue was obtained.

[0059] Comparative Example 2 This comparative example is largely the same as Comparative Example 1, except that 55 parts of polycarbonate-type polyurethane acrylate are replaced with 55 parts of modified silicone acrylate resin.

[0060] Comparative Example 3 is similar to Comparative Example 1 in most steps, except that 25 parts of cyclotrimethylolpropane methyl acetal acrylate are replaced with 25 parts of high adhesion diluent.

[0061] The performance of the above embodiments and comparative examples was tested using the following methods: (1) Surface condition The resin compositions obtained in the above examples and comparative examples were coated with a 1 mm thick adhesive layer onto an aluminum substrate using a coating tool, and then placed under an ultraviolet light source (405 nm, 500 mW / cm²). 2 After irradiation curing for at least 15 seconds, use the touch test to determine the surface dryness of the adhesive layer. If it is tacky, it is not surface dry; if it is not tacky, it is surface dry. Calculate the minimum radiation energy (mJ / cm²) required for surface dryness. 2 ).

[0062] (2) Curing depth The resin compositions obtained in the above examples and comparative examples were poured into a circular groove mold with a depth of 8 mm and placed in an ultraviolet light source (405 nm, 500 mW / cm²). 2 After 30 seconds of radiation curing, remove the product and allow it to cool. Then, remove the cured adhesive layer and rinse it with ethanol to remove any remaining uncured adhesive layer at the bottom. Use a micrometer to measure the thickness of the adhesive layer, which is the curing depth.

[0063] (3) Tensile shear strength Wipe the surface of the aluminum substrate with ethanol and wait for the ethanol to evaporate completely. Then, attach 0.2mm aluminum foil tape to one end of the substrate and apply the resin composition obtained in the above examples and comparative examples to one end of the aluminum substrate, ensuring the resin composition is evenly applied to the bonding area. Next, overlap the two substrates in a staggered manner, clamp them with transparent plastic clips, and place the sample in a UV light source (405nm, 500mW / cm²). 2 After radiation curing for 30 seconds to ensure full curing, remove the product. Tensile shear strength testing was conducted according to GB / T 7124-2008 standard on an electronic tensile testing machine at a temperature of 25 ℃, with an overlap area of ​​312.5 mm². 2 The test rate was 5 mm / min. (4) Elongation at break Tensile strength tests were performed using GB / T 528 / 92 standard. The resin compositions obtained in the above examples and comparative examples were placed in a dumbbell-shaped polytetrafluoroethylene mold and exposed to an ultraviolet light source (405nm, 500mW / cm²). 2 After radiation curing for 30 seconds to fully cure, remove the specimen. Test the width and thickness of the narrow parallel section of the dumbbell-shaped specimen. Place the dumbbell-shaped specimen evenly on the upper and lower clamps and stretch it at a test speed of 50 mm / min. Measure the elongation at fracture.

[0064] (5) Air tightness (resistance to thermal shock) The resin compositions obtained in the above examples and comparative examples were injected into a 5mm deep groove between a custom-made aluminum housing and an aluminum cover plate using a dispensing process, and then placed in an ultraviolet light source (405nm, 500mW / cm²). 2 After radiation curing for 30 seconds to fully cure, remove the sample and let it stand for 1 day before placing it in a temperature shock test chamber. The temperature shock conditions are -40~125℃, with temperature switching every 30 minutes. The test duration is 250, 500, 750, and 1000 hours. The airtightness is tested at each time stage. If airtightness failure occurs, the test duration is determined to be the thermal shock duration. The specific steps for the airtightness test are as follows: connect the aluminum shell sample to the airtightness test equipment, introduce 0.2 bar of air pressure, maintain for 2 minutes, and immerse the aluminum shell sample in water during the air supply. If bubbles or air leakage appear at the interface between the aluminum shell and the aluminum cover plate, it is determined to be an airtightness failure.

[0065] The test results are shown in Table 1.

[0066] Table 1 Based on the data analysis in Table 1, comparing Example 1 and Comparative Example 1, the UV black adhesive prepared from commercially available polycarbonate-type polyurethane acrylate showed poorer toughness and thermal shock resistance compared to the UV black adhesive prepared in this application, exhibiting superior sealing performance. It failed to maintain airtightness for 250 hours under thermal shock conditions of -40~125℃. Compared to Comparative Example 2, the commercially available cyclotrimethylolpropane methyl acetal acrylate, when used in combination with an acrylic reactive diluent, could not maximize the adhesive properties of the modified organosilicon acrylate resin prepared in this application after curing, exhibiting poorer toughness and thermal shock resistance. It also failed to maintain airtightness for 500 hours under thermal shock conditions of -40~125℃. However, the modified organosilicon acrylate resin prepared in this application improved surface drying performance. Comparative Examples 1 and 3 show that the tensile shear strength increased when commercially available polycarbonate-type polyurethane acrylate was combined with a high-adhesion diluent, indicating that the high-adhesion diluent prepared in this application has an advantage in increasing adhesive strength when combined with the resin.

[0067] Compared with Examples 1-5, it can be seen that the formulation of this example achieves the best overall performance, with a minimum energy required for surface drying of 8000 mJ / cm². 2 The cured depth is 5.82 mm, the tensile shear strength is 5.15 MPa, the elongation at break is 146%, and it can withstand 1000 hours of thermal shock under conditions of -40~125℃. As in Examples 2-3, when the content of modified silicone acrylate resin decreases, the flexibility and adhesion properties decrease. However, when the content of modified silicone acrylate resin is less than 45 parts, as in Example 7, the toughness decreases significantly, dropping to 128%, resulting in poor thermal shock resistance. As in Examples 4-5, when the content of modified silicone acrylate resin increases, the flexibility increases, but the adhesion properties decrease due to the decrease in crosslinking density. When the content of modified silicone acrylate resin exceeds 65 parts, as in Example 6, although the toughness increases, the photocuring efficiency decreases, leading to an increase in the minimum energy required for the surface drying of UV black glue. At the same time, the adhesion strength decreases, resulting in a significant decrease in thermal shock resistance. Compared with Examples 1 and 6, it can be seen that when the content of high adhesion diluent decreases, the crosslinking density decreases and the bonding strength decreases. For example, in Example 11, when less than 20 parts of high adhesion diluent are added, the content of reactive acrylate decreases, which leads to a decrease in the UV black glue curing efficiency and a decrease in crosslinking density. As a result, the minimum energy required for surface drying increases, and the bonding performance and resistance to thermal shock decrease sharply. Compared with Examples 1, 7, and 10, it can be seen that when the content of high adhesion diluent increases, the toughness and adhesion performance decrease due to the excessively high crosslinking density. For example, in Example 10, when the content of high adhesion diluent is greater than 30 parts, the resistance to thermal shock decreases sharply.

[0068] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A UV black adhesive with excellent sealing performance, characterized in that, The UV black adhesive comprises modified silicone acrylate resin, diluent, photoinitiator, and color paste; The modified organosilicon acrylate resin is prepared from hydroxy acrylate derivatives, polyether diols, hydroxyl-terminated polysiloxanes, and alicyclic diisocyanates. The diluent includes a high-adhesion diluent and an acrylate reactive diluent; The high-adhesion diluent was prepared from isocyanate acrylic acid derivatives and triethylene glycol monomethyl ether; The photoinitiator includes one or more of the following: 2-benzyl-2-dimethylamino-4-morpholinyl phenylbutanone, 2-methyl-4-methylthio-2-morpholinyl phenylpropanone, 2-(4-methylbenzyl)-2-dimethylamino-4-morpholinyl phenylbutanone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoyl phenyl ethyl hypophosphite, bis(2,4,6-trimethylbenzoyl)phenyl phosphorus oxide, 2-isopropylthioxanthrone, 2,4-diethylthioxanthrone, and 1-hydroxycyclohexylphenyl ketone; The color paste includes one or more of carbon black, titanium black, and aniline black, with a particle size not greater than 160 nm.

2. The UV black adhesive with excellent sealing performance according to claim 1, characterized in that, The mass ratio of the high-adhesion diluent to the acrylate reactive diluent is (1.3~2):

1.

3. The UV black adhesive with excellent sealing performance according to claim 1, characterized in that, The preparation method of the modified organosilicon acrylate resin includes the following steps: Step 1: Dehydrate the hydroxy acrylate derivative and the hydroxyl-terminated polysiloxane under vacuum at 90-110°C for 3-6 hours; Step 2: Mix the alicyclic diisocyanate with the first catalyst, the first polymerization inhibitor and the first antioxidant and heat to 60~80℃. Add the hydroxyl acrylate derivative dropwise. When the NCO value decreases to 50% of the initial value, intermediate product 1 is obtained. Step 3: Continue to add hydroxyl-terminated polysiloxane to intermediate product 1, heat to 70~90℃, and stop the reaction when the NCO content drops below 0.1% to prepare modified organosilicon acrylate resin.

4. The UV black adhesive with excellent sealing performance according to claim 3, characterized in that, The molecular weight of the double-hydroxyl-terminated polysiloxane is 1000~2000 g / mol; The hydroxyl-containing acrylate derivatives include trimethylolpropane diacrylate; The alicyclic diisocyanate includes at least one of isophorone diisocyanate, dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate.

5. The UV black adhesive with excellent sealing performance according to claim 3, characterized in that, In the preparation method of the high-toughness photocurable resin, the molar ratio of alicyclic diisocyanate, hydroxyl-containing acrylate derivative and dihydroxyl-terminated polysiloxane is 1:(1~1.1):(1~1.1).

6. The UV black adhesive with excellent sealing performance according to claim 1, characterized in that, The preparation method of the high-adhesion diluent includes the following steps: The triethylene glycol monomethyl ether was dehydrated; the isocyanate acrylic acid derivative, the second catalyst, the second polymerization inhibitor, and the second antioxidant were mixed and heated to 60-80°C, and the triethylene glycol monomethyl ether was added dropwise. The reaction was stopped when the NCO content decreased to below 0.1%, and a high-adhesion diluent was prepared.

7. The UV black adhesive with excellent sealing performance according to claim 5, characterized in that, In the preparation method of the high adhesion diluent, the molar ratio of triethylene glycol monomethyl ether and isocyanate acrylic acid derivative is (1~1.1):1; The isocyanate acrylic derivatives include one or more of ethyl isocyanate, 1,1-di(acryloyloxymethyl)ethyl isocyanate, and ethyl isocyanate methacrylate.

8. The UV black adhesive with excellent sealing performance according to claim 1, characterized in that, The UV black adhesive with excellent sealing performance also includes additives; The UV black adhesive comprises the following raw materials in parts by weight: 45-65 parts of high-toughness light-curing resin, 35-45 parts of diluent, 1.5-4 parts of free radical photoinitiator, 0.02-0.05 parts of color paste, and 3-9 parts of additives.

9. A method for preparing a UV black adhesive with excellent sealing performance as described in any one of claims 1-8, characterized in that, Includes the following steps: Modified silicone acrylate resin, high adhesion diluent, acrylate reactive diluent, free radical photoinitiator and additives were mixed evenly under light-protected conditions according to the weight parts, and after vacuum degassing, the UV black glue with excellent sealing performance was obtained.

10. The application of a UV black adhesive with excellent sealing performance as described in any one of claims 1-8 or a UV black adhesive with excellent sealing performance prepared by the preparation method described in any one of claims 9 in sealing applications such as screen bezels or controller housings.

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