UV-thermal dual-curing adhesive, preparation method and application thereof

Abstract

The application provides a UV-thermal dual-curing adhesive as well as a preparation method and application thereof, and belongs to the technical field of adhesives.The preparation raw material of the UV-thermal dual-curing adhesive comprises the following components in terms of weight fractions: 10-40 parts of silicon-free epoxy resin;5-35 parts of epoxy silicon resin;5-40 parts of active diluent;0.5-5 parts of cationic photoinitiator;0.1-3 parts of cationic thermal initiator;0.5-10 parts of thixotropic agent;0.1-2 parts of antioxidant;and 30-60 parts of filler.The UV-thermal dual-curing adhesive provided by the application introduces epoxy silicon resin on the basis of a system containing silicon-free epoxy resin, and the two kinds of resins jointly act to adjust the UV curing and thermal curing strength, so that the prepared UV-thermal dual-curing adhesive has high bonding property and high weather resistance.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, and relates to a UV-thermal dual-curing adhesive, its preparation method and application, specifically a UV-thermal dual-curing adhesive with high adhesion and high weather resistance, its preparation method and application. Background Technology

[0002] With the rapid advancement of smart hardware, such as the continuous upgrading of smart terminal products like smartphones, electric vehicles, and PCs, the requirements for adhesives are becoming increasingly stringent. Traditional single-curing methods (such as UV curing or heat curing alone) are no longer sufficient to meet the rapid assembly and high-quality bonding needs of these high-end products. While UV curing technology offers advantages such as rapid curing and high production efficiency, it suffers from problems like incomplete curing and inability to cure irregular or irregularly shaped products. Heat-curing adhesives, on the other hand, while exhibiting strong adhesion and good weather resistance, suffer from slow curing speeds and high energy consumption. Therefore, a dual-curing method combining UV curing and heat curing has emerged to address the shortcomings of single-curing methods.

[0003] In high-end electronics, automotive manufacturing, aerospace, and other fields, there are extremely high requirements for the bonding strength and weather resistance of adhesives. UV-thermal dual-curing adhesives, through a dual curing mechanism, can achieve high bonding strength in a short time and possess excellent water resistance, high temperature resistance, and aging resistance, thus meeting the stringent requirements of these fields.

[0004] While UV-thermal dual-curing adhesives combine the advantages of both UV light curing and thermal curing in many ways, they still have some technical drawbacks. UV-thermal dual-curing adhesives require simultaneous UV light irradiation and high-temperature heating for curing. The UV light curing stage typically achieves rapid curing, but the thermal curing stage is relatively slower. This inconsistency in curing speed can lead to differences in the degree of curing in different areas of the product, thus affecting the overall performance. UV-thermal dual-curing adhesives may experience volume shrinkage during curing, especially during the UV light curing stage. This shrinkage not only affects the dimensional accuracy of the product but can also cause stress concentration at the bond interface, thereby reducing bond strength. To reduce shrinkage, precise adjustments to the formulation are required, often necessitating a trade-off between performance and cost. The thermal curing stage generally improves the heat and weather resistance of the adhesive, but this can also introduce other problems. For example, excessively high curing temperatures may cause deformation or damage to some substrates, and also affect the product's appearance and performance. Therefore, formulation design must comprehensively consider various factors to ensure that the product possesses excellent heat and weather resistance without negatively impacting other properties. The formulation design of UV-thermal dual-curing adhesives is relatively complex and requires consideration of the combined effects of various factors. For example, the selection and dosage of photoinitiators and thermal initiators, the type and properties of the resin matrix, and the type and proportion of fillers and additives will all have a significant impact on the curing effect and performance of the product.

[0005] Therefore, there is a desire in the field to develop a UV-thermal dual-curing adhesive that has high adhesion and high weather resistance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a UV-thermal dual-curing adhesive, its preparation method, and its application, specifically providing a UV-thermal dual-curing adhesive with high adhesion and high weather resistance, its preparation method, and its application.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a UV-thermal dual-curing adhesive, wherein the raw materials for preparing the UV-thermal dual-curing adhesive comprise the following components in parts by weight:

[0009]

[0010]

[0011] The UV-thermal dual-curing adhesive provided by this invention introduces epoxy silicone resin into the system based on the presence of silicone-free epoxy resin. The two resins work together to adjust the UV curing and thermal curing strength, so that the prepared UV-thermal dual-curing adhesive has both high adhesion and high weather resistance.

[0012] In this invention, the amount of the raw materials used in the preparation of the UV-thermal dual-curing adhesive, based on parts by weight, can be 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, etc.

[0013] In this invention, the amount of epoxy silicone resin used in the preparation of the UV-thermal dual-curing adhesive can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 35 parts, etc., by weight.

[0014] In this invention, the amount of reactive diluent used in the preparation of the UV-thermal dual-curing adhesive, based on the weight parts, can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, etc.

[0015] In this invention, the raw materials for preparing the UV-thermal dual-curing adhesive, by weight, include 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc., of the cationic photoinitiator.

[0016] In this invention, the amount of cationic thermal initiator used in the preparation of the UV-thermal dual-curing adhesive, based on the weight parts, can be 0.1 parts, 0.3 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.3 parts, 1.5 parts, 1.6 parts, 1.8 parts, 2 parts, 2.3 parts, 2.5 parts, 2.6 parts, 2.8 parts, 3 parts, etc.

[0017] In this invention, the amount of thixotropic agent used in the preparation of the UV-thermal dual-curing adhesive can be 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc., by weight.

[0018] In this invention, the amount of antioxidant used in the preparation of the UV-thermal dual-curing adhesive can be 0.1 parts, 0.3 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.3 parts, 1.5 parts, 1.6 parts, 1.8 parts, 2 parts, etc., by weight.

[0019] In this invention, the raw materials for preparing the UV-thermal dual-curing adhesive, by weight, include fillers in amounts of 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, and 60 parts.

[0020] Preferably, the silicone-free epoxy resin includes any one or a combination of at least two of alicyclic epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, phenolic epoxy resin, vinyl epoxy resin, hydrogenated bisphenol A epoxy resin, or hydrogenated bisphenol F epoxy resin.

[0021] Preferably, the silicone-free epoxy resin comprises any one or a combination of at least two of the following: bis-(3,4-epoxycyclohexylmethyl)adipate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, di-4-epoxycyclohexane, 1,2:5,6-diepoxyhexahydroindane, 4-vinylepoxycyclohexane, 3,4-epoxycyclohexylmethacrylate, and 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester.

[0022] Preferably, the epoxy silicone resin comprises any one or a combination of at least two of the following: 1,1,3,3-tetramethyl-1,3-bis-[2-[7-oxybicyclo[4.1.0]hept-3-yl]ethyl]disiloxane, tetracyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane, and 1,3-bis(3-glycidyl etheroxypropyl)-1,1,3,3-tetramethyldisiloxane.

[0023] Preferably, the reactive diluent includes any one or a combination of at least two of the following: alkenyl ether reactive diluents, ketene diethanol condensate reactive diluents, epoxy reactive diluents, epoxidized triglyceride reactive diluents, oxetane reactive diluents, and mixed reactive diluents containing epoxy enol ether groups.

[0024] Preferably, the reactive diluent comprises any one or a combination of at least two of the following: 3-ethyl-3-oxetane methanol, 3-ethyl-3-chloromethyloxetane, 3,3-[oxybismethylene]bis[3-ethyl]oxetane, 3-ethyl-3-[(2-ethyl)-hexyloxymethyl]oxetane, 3-ethyl-3-[(benzyloxy)methyl]oxetane, 3-ethyl-3-[(phenoxy)methyl]oxetane, and 3-ethyl-3-allylmethoxyoxetane.

[0025] Preferably, the cationic photoinitiator comprises any one or a combination of at least two of aromatic iodonium salts, aromatic sulfonium salts, aromatic diazoonium salts, aromatic phosphonium salts, and aromatic ferrocene salts.

[0026] Preferably, the cationic photoinitiator comprises any one or a combination of at least two of the following: diarylpentophenylboronic acid iodonium salt, diarylhexafluorophosphate iodonium salt, diarylhexafluoroantimony iodonium salt, triarylhexafluoroantimony sulfonium salt, triarylhexafluorophosphate sulfonium salt, and aramidoferrohexafluorophosphate.

[0027] Preferably, the cationic photoinitiator comprises diphenyl-(4-phenylthio)phenylsulfonium hexafluoroantimonate.

[0028] Preferably, the cationic thermal initiator includes any one or a combination of at least two of CXC1612, Vicbase TC3631, Vicbase TC3632, Vicbase TC3634, CTI-100, CTI-200 or CTI-300.

[0029] Preferably, the thixotropic agent comprises fumed silica and / or precipitated silica.

[0030] Preferably, the antioxidant includes aromatic amine antioxidants and / or hindered phenolic antioxidants.

[0031] Preferably, the aromatic amine antioxidant includes any one or a combination of at least two of diaryl secondary amines, p-phenylenediamine, ketamines, and aldehyde amines.

[0032] Preferably, the hindered phenolic antioxidant includes any one or a combination of at least two of 2,6-di-tert-butyl-4-methylphenol, antioxidant AO-20, and antioxidant 1076.

[0033] Preferably, the antioxidant is antioxidant AO-20.

[0034] Preferably, the filler comprises spherical silica powder and / or talc powder.

[0035] In a second aspect, the present invention provides a method for preparing a UV-thermal dual-curing adhesive as described in the first aspect, the preparation method comprising the following steps:

[0036] The non-silicone epoxy resin, epoxy silicone resin, reactive diluent, and cationic photoinitiator are mixed and heated until the cationic photoinitiator dissolves. Then, thixotropic agent, filler, antioxidant, and cationic thermal initiator are added and mixed again to obtain the UV-thermal dual-curing adhesive.

[0037] Preferably, the mixing is carried out under yellow light conditions.

[0038] Preferably, the preparation method specifically includes the following steps: mixing silicone-free epoxy resin, epoxy silicone resin, reactive diluent, and cationic photoinitiator under yellow light conditions, heating until the cationic photoinitiator dissolves, performing a first dispersion, then adding a thixotropic agent, performing a second dispersion, then adding a filler, performing a third dispersion, then adding an antioxidant, performing a fourth dispersion, cooling, adding a cationic thermal initiator, performing a fifth dispersion, cooling, performing a sixth dispersion, packing into tubes, and freezing for storage to obtain the UV-thermal dual-curing adhesive.

[0039] Preferably, the rotation speed of the first dispersion is 1300-1700 rpm, such as 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm, 1500 rpm, 1550 rpm, 1600 rpm, 1650 rpm, 1700 rpm, etc., and the time is 1-3 min, such as 1 min, 2 min, 3 min, etc.

[0040] Preferably, the rotation speed of the second dispersion is 1300-1700 rpm, such as 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm, 1500 rpm, 1550 rpm, 1600 rpm, 1650 rpm, 1700 rpm, etc., and the time is 1-3 min, such as 1 min, 2 min, 3 min, etc.

[0041] Preferably, the rotation speed of the third dispersion is 1300-1700 rpm, such as 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm, 1500 rpm, 1550 rpm, 1600 rpm, 1650 rpm, 1700 rpm, etc., and the time is 4-6 min, such as 4 min, 5 min, 6 min, etc.

[0042] Preferably, the rotation speed of the fourth dispersion is 1300-1700 rpm, such as 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm, 1500 rpm, 1550 rpm, 1600 rpm, 1650 rpm, 1700 rpm, etc., and the time is 1-3 min, such as 1 min, 2 min, 3 min, etc.

[0043] Preferably, the rotation speed of the fifth dispersion is 1300-1700 rpm, such as 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm, 1500 rpm, 1550 rpm, 1600 rpm, 1650 rpm, 1700 rpm, etc., and the time is 1-3 min, such as 1 min, 2 min, 3 min, etc.

[0044] Preferably, the fifth dispersion is followed by a vacuum degassing step.

[0045] Preferably, the rotation speed of the sixth dispersion is 1300-1700 rpm, such as 1300 rpm, 1350 rpm, 1400 rpm, 1450 rpm, 1500 rpm, 1550 rpm, 1600 rpm, 1650 rpm, 1700 rpm, etc., and the time is 1-3 min, such as 1 min, 2 min, 3 min, etc.

[0046] Preferably, the sixth dispersion is followed by a vacuum degassing step.

[0047] Thirdly, the present invention provides an application of the UV-thermal dual-curing adhesive as described in the first aspect in electronic products, automobile manufacturing, communications, or aerospace.

[0048] Compared with the prior art, the present invention has at least the following beneficial effects:

[0049] The UV-thermal dual-curing adhesive provided by this invention introduces epoxy silicone resin into the system based on the presence of silicone-free epoxy resin. The two resins work together to adjust the UV curing and thermal curing strength, so that the prepared UV-thermal dual-curing adhesive has both high adhesion and high weather resistance. Detailed Implementation

[0050] 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.

[0051] Examples 1-5

[0052] In Examples 1-5, a UV-thermal dual-curing adhesive is provided respectively. The raw materials and amounts (parts by weight) used in the preparation of the UV-thermal dual-curing adhesive are shown in Table 1.

[0053] Table 1

[0054]

[0055] The preparation method of UV-thermal dual-curing adhesive includes the following steps:

[0056] Under yellow light conditions, silicone-free epoxy resin, epoxy silicone resin, reactive diluent, and cationic photoinitiator are mixed in a high-speed dispersion tank and heated until the cationic photoinitiator dissolves. Then, the high-speed dispersion tank is placed in a homogenizer and dispersed at 1500 rpm for 2 min. Next, a thixotropic agent is added and stirred, and the mixture is dispersed in a homogenizer at 1500 rpm for 2 min. Then, filler is added and the mixture is dispersed in a homogenizer at 1500 rpm for 5 min. Finally, an antioxidant is added and stirred, and the mixture is dispersed in a homogenizer at 1500 rpm for 2 min. After cooling, a cationic thermal initiator is added and the mixture is dispersed in a homogenizer at 1500 rpm for 2 min. After vacuum degassing and cooling, the mixture is dispersed in a homogenizer at 1500 rpm for 2 min, and then vacuum degassed. The mixture is then packaged into tubes and stored frozen to obtain the UV-thermal dual-curing adhesive.

[0057] Comparative Examples 1-4

[0058] In Comparative Examples 1-4, a UV-thermal dual-curing adhesive is provided respectively. The raw materials and amounts (parts by weight) for preparing the UV-thermal dual-curing adhesive are shown in Table 2. The preparation method is the same as in Examples 1-5.

[0059] Table 2

[0060]

[0061] Comparative Example 5

[0062] The only difference between this comparative example and Example 1 is that the epoxy silicone resin (1,1,3,3-tetramethyl-1,3-bis-[2-[7-oxybicyclo[4.1.0]hept-3-yl]ethyl]disiloxane) is replaced with an equal weight of γ-glycidoxypropyltrimethoxysilane.

[0063] The UV-thermal dual-curing adhesives provided in the examples and comparative examples were respectively applied between two aluminum-silicon alloy (AlSi12) sheets and two anodized aluminum sheets, and then cured under the following conditions: first at an energy density of 150 mW / cm². 2 The sample was cured under UV light for 4 seconds and then heat-cured at 80°C for 60 minutes. The initial tensile shear strength and the tensile shear strength after being placed at 85°C and 85% humidity for 1000 hours were tested in accordance with GB / T 7124-2008 standard. The performance test results are shown in Table 3.

[0064] Table 3

[0065]

[0066] As can be seen from Table 3, the UV-thermal dual-curing adhesives provided in the embodiments of the present invention all have excellent adhesion and weather resistance (when the substrate is AlSi12 / AlSi12, the initial tensile shear strength is 9.1-12.5 MPa, and the tensile shear strength after aging is 7.3-11.6 MPa; when the substrate is anodized aluminum oxide / anodized aluminum oxide, the initial tensile shear strength is 9.2-12.3 MPa, and the tensile shear strength after aging is 7.2-11.5 MPa).

[0067] Compared with Example 1, the adhesion and weather resistance of the UV-thermal dual-curing adhesives provided in Comparative Example 1 and Comparative Example 2 were significantly reduced; the adhesion and weather resistance of the UV-thermal dual-curing adhesive provided in Comparative Example 4 were significantly reduced; and the adhesion and weather resistance of the UV-thermal dual-curing adhesive provided in Comparative Example 5 were significantly reduced.

[0068] Compared with Example 3, the UV-thermal dual-curing adhesive provided in Comparative Example 3 showed a significant decrease in both adhesion and weather resistance.

[0069] The applicant declares that this invention illustrates the UV-thermal dual-curing 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, additions of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A UV-thermal dual-curing adhesive, characterized in that, The raw materials for preparing the UV-thermal dual-curing adhesive include the following components by weight: 10-40 parts without silicone epoxy resin; 5-35 parts of epoxy silicone resin; 5-40 parts of reactive diluent; 0.5–5 parts of cationic photoinitiator; 0.1–3 parts of cationic thermal initiator; Thixotropic agent 0.5–10 parts; Antioxidant 0.1 to 2 parts; 30-60 parts of filler; The epoxy silicone resin includes 1,1,3,3-tetramethyl-1,3-bis-[2-[7-oxybicyclo[4.1.0]hept-3-yl]ethyl]disiloxane or tetraepoxycyclohexylethyl-2,4,6,8-tetramethylcyclotetrasiloxane; The silicone-free epoxy resin includes any one or a combination of at least two of the following: bis-(3,4-epoxycyclohexylmethyl) adipate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarbamate, and 4-vinylepoxycyclohexane. The UV-thermal dual-curing adhesive is prepared by the following method, which includes the following steps: The non-silicone epoxy resin, epoxy silicone resin, reactive diluent, and cationic photoinitiator are mixed and heated until the cationic photoinitiator dissolves. Then, thixotropic agent, filler, antioxidant, and cationic thermal initiator are added and mixed again to obtain the UV-thermal dual-curing adhesive.

2. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The reactive diluent includes any one or a combination of at least two of the following: alkenyl ether reactive diluents, ketene diethanolate reactive diluents, epoxy reactive diluents, and oxetane reactive diluents.

3. The UV-thermal dual-curing adhesive according to claim 2, characterized in that, The epoxy-based reactive diluents include epoxidized triglyceride reactive diluents or mixed reactive diluents containing epoxy and enol ether groups.

4. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The cationic photoinitiator includes any one or a combination of at least two of the following: aromatic iodonium salts, aromatic sulfonium salts, aromatic diazonium salts, aromatic phosphonium salts, and aromatic ferrocene salts. The cationic thermal initiator includes any one or a combination of at least two of CXC1612, Vicbase TC3631, Vicbase TC3632, Vicbase TC3634, CTI-100, CTI-200 or CTI-300.

5. The UV-thermal dual-curing adhesive according to claim 1, characterized in that, The thixotropic agent includes fumed silica and / or precipitated silica; The antioxidants include aromatic amine antioxidants and / or hindered phenolic antioxidants; The filler includes spherical silica powder and / or talc powder.

6. A method for preparing a UV-thermal dual-curing adhesive as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: The non-silicone epoxy resin, epoxy silicone resin, reactive diluent, and cationic photoinitiator are mixed and heated until the cationic photoinitiator dissolves. Then, thixotropic agent, filler, antioxidant, and cationic thermal initiator are added and mixed again to obtain the UV-thermal dual-curing adhesive.

7. The preparation method according to claim 6, characterized in that, The preparation method specifically includes the following steps: Under yellow light conditions, silicone-free epoxy resin, epoxy silicone resin, reactive diluent, and cationic photoinitiator are mixed and heated until the cationic photoinitiator dissolves for the first dispersion. Then, a thixotropic agent is added for the second dispersion, followed by the addition of filler for the third dispersion, then the addition of antioxidant for the fourth dispersion, followed by cooling, the addition of cationic thermal initiator for the fifth dispersion, cooling, and finally the sixth dispersion to obtain the UV-thermal dual-curing adhesive. The rotation speeds for the first, second, fourth, fifth, and sixth dispersions were each 1300–1700 rpm, and the dispersion times were each 1–3 min; the rotation speed for the third dispersion was 1300–1700 rpm, and the dispersion time was 4–6 min. The fifth and sixth dispersions are followed by a vacuum degassing step.

8. The application of a UV-thermal dual-curing adhesive as described in any one of claims 1-5 in electronic products, automobile manufacturing, communications, or aerospace.

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