Cationic epoxy resin light-curing adhesive and preparation method and application thereof

Abstract

The present invention relates to the technical field of photocurable materials, and in particular to a cationic epoxy resin photocurable adhesive and a preparation method and application thereof. The cationic epoxy resin photocurable adhesive provided by the present invention comprises the following components by weight percentage: 25-55% alicyclic epoxy resin, 10-25% organosilicon-modified alicyclic epoxy resin, 10-25% oxetane, 5-20% rosin ester diol, 5-10% adhesion promoter, 0.3-3% sensitizer, and 0.1-2% photoacid generator. The cationic epoxy resin photocurable adhesive provided by the present invention is used in the bonding of electronic materials, and has the advantages of high adhesion and high elongation, especially the adhesion to copper materials is higher than that of conventional cationic epoxy adhesives, which solves the defects of conventional cationic photocurable adhesives, and the cured product has excellent performance, high aging reliability, and a wide range of applications.

Description

Technical Field

[0001] The present invention relates to the technical field of photocurable materials, and in particular to a cationic epoxy resin photocurable adhesive and a preparation method and application thereof. Background Art

[0002] Cationic light-curing adhesives are widely used in electronics, electrical appliances, automobiles, aerospace, shipbuilding and other industries due to their unique curing principle and good bonding performance, temperature resistance, electrical properties and other advantages. Epoxy resins have good physical and chemical properties after curing and are widely used in coatings, adhesives, machinery, construction, electronic and electrical insulation materials, aerospace and other sectors of the national defense and national economy. Epoxides can be polymerized and cross-linked by UV light radiation in the presence of cationic photoinitiators, and the cured epoxy resins have good wear resistance and corrosion resistance.

[0003] However, cationic epoxy resin photocuring adhesive also has its own limitations. Compared with free radical polymerization acrylic resin, cationic polymerization epoxy resin has the following disadvantages: (1) The reaction speed of cationic polymerization is slower than that of free radical system, and it is not suitable for scenes with fast processing speed; (2) The reaction depth of epoxy resin system is shallower than that of acrylic system, and thicker products cannot be formed; (3) Compared with free radical photoinitiators, cationic initiators have lower absorption wavelength and narrower absorption range; (4) The adhesion of cationic system is lower; (5) The elongation of cationic system is low, generally less than 10%. Therefore, cationic epoxy photocuring adhesive has obvious limitations in practical applications. Summary of the invention

[0004] In order to solve the above technical problems existing in the prior art, the present invention provides a cationic epoxy resin photocuring adhesive and a preparation method and application thereof.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] The first aspect of the present invention is to provide a cationic epoxy resin photocuring adhesive, which includes the following components in weight percentage: 25-55% of alicyclic epoxy resin, 10-25% of silicone-modified alicyclic epoxy resin, 10-25% of oxetane, 5-20% of rosin ester diol, 5-10% of adhesion promoter, 0.3-3% of sensitizer, and 0.1-2% of photoacid generator.

[0007] The cationic epoxy resin photocuring adhesive provided by the present invention has excellent toughness and elongation, improved adhesion, and a wide range of applicable light source wavelengths by adding silicone-modified alicyclic epoxy resin, cooperating with other components, and adjusting the weight ratio of each component.

[0008] On the basis of the above technical solution, the present invention can also make the following technical improvements:

[0009] Furthermore, the organosilicon-modified alicyclic epoxy resin has a structural formula shown in formula (I):

[0010]

[0011] Wherein, b≥3, and a and b are both integers.

[0012] The beneficial effect of adopting the above-mentioned further technical scheme is that the silicone-modified alicyclic epoxy resin is a silicone oligomer containing 3 or more alicyclic epoxy groups, and the alicyclic epoxy groups are on the side chains. By rationally designing the segment structure of silicone and the position and number of epoxy functional groups, the silicone-modified alicyclic epoxy resin has excellent toughness and elongation, which greatly improves the toughness and elongation of the cationic epoxy resin photocuring adhesive.

[0013] Furthermore, the organosilicon-modified alicyclic epoxy resin is prepared by the following method: 4-vinyl-1-cyclohexene-1,2-epoxy and a platinum catalyst are mixed evenly and heated, hydrogenated silicone oil is added dropwise, the dropping speed and the reaction temperature are controlled, the reaction temperature does not exceed 60°C, the dropping is completed, the temperature is increased and the reaction is carried out to obtain the organosilicon-modified alicyclic epoxy resin.

[0014] The reaction formula of silicone-modified alicyclic epoxy resin is as follows:

[0015]

[0016] Furthermore, the weight average molecular weight of the rosin ester diol is 2000-4000, and the rosin ester diol has a structural formula shown in formula (II):

[0017]

[0018] The beneficial effect of adopting the above further technical scheme is that: rosin ester diol is a diol containing a rosin structure, and the hydroxyl structure therein is conducive to introducing the rosin structure into the macromolecule of the polymer, so that the main chain contains the rosin structure. The rosin structure on the main chain helps to further improve the adhesion of the cationic epoxy resin photocuring adhesive, especially the adhesion to the copper substrate is greatly improved.

[0019] Furthermore, the adhesion promoter is rosin phenol, having the structural formula shown in formula (III):

[0020]

[0021] The beneficial effect of adopting the above further technical solution is that rosin phenol is the reactant of rosin and phenol, and the molecular structure of rosin phenol contains both carboxyl and hydroxyl structures, wherein the hydroxyl structure reacts with the alicyclic epoxy to connect the rosin phenol to the macromolecule of the polymer, and the carboxyl structure has good adhesion to the substrate, especially the copper substrate.

[0022] Further, the sensitizer is any one or more of anthracene derivatives, benzoin derivatives, benzophenone and its derivatives, acetophenone and its derivatives, methyl o-benzoylbenzoate, and peroxide. The sensitizer is selected from 9,10-dibutoxyanthracene, benzoin methyl ether, benzoin isopropyl ether, α,α-dimethoxy-α-phenylacetophenone, 2-chlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis(dimethylamino)benzophenone, 4,4'-bis(diethylamino)benzophenone, benzoyl peroxide, cumene hydroperoxide, Akzo Nobel's Trigonox C (TBPB, CAS: 614-45-9), Trigonox B (DTPB, CAS: 110-05-4), and the like.

[0023] Furthermore, the photoacid generator is any one or more of aromatic diazonium salt, triarylsulfonium salt, diaryliodonium salt, and aromatic ferrocenium salt. The triarylsulfonium salt is a mixed triaryl hexafluoroantimonate sulfonium salt cationic photoinitiator, and the aromatic ferrocenium salt is IRGACURE 250, IRGACURE 261, IRGACURE 262, etc.

[0024] The beneficial effect of adopting the above further technical solution is that by using the sensitizer in combination with the photoacid generator, the cationic epoxy resin photocuring adhesive can be cured under a long wavelength 470nm light source, while conventional photocuring adhesive can only be cured under a short wavelength (365nm) light source.

[0025] Furthermore, the alicyclic epoxy resin refers to a compound having at least an alicyclic structure and an epoxy group in the molecule, such as the commercially available products "CELLOXIDE 2021P" and "CELLOXIDE 2081" of Japan Daicel, and Nantong Xinnaxi S-60.

[0026] Furthermore, the oxetane refers to an oxetane-containing compound, for example, OXT-121, OXT-221, OXT-101, OXT-212, etc. synthesized by East Asia of Japan.

[0027] The second aspect of the present invention is to provide a method for preparing the above-mentioned cationic epoxy resin photocuring adhesive, comprising the following steps: weighing alicyclic epoxy resin, silicone-modified alicyclic epoxy resin, oxetane, rosin ester diol, adhesion promoter, sensitizer, and photoacid generator, adding them into a mixer in sequence, evacuating to a vacuum degree of -0.08 to -0.05 MPa, controlling the rotation speed to 500 to 1000 r / min, stirring for 0.5 to 2 hours, letting it naturally dry to room temperature, and sealing and packaging.

[0028] Another aspect of the present invention is to provide the use of the cationic epoxy resin photocuring adhesive in bonding electronic materials, wherein the cationic epoxy resin photocuring adhesive is coated on the electronic material and placed under a light source for irradiation and curing.

[0029] Furthermore, the electronic material is a copper substrate, and the wavelength of the light source is 365-470nm.

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] The cationic epoxy resin light-curing adhesive obtained by the present invention has the advantage of high adhesion, especially higher adhesion to copper materials than conventional cationic epoxy adhesive;

[0032] It has a high elongation, which solves the defects of conventional cationic light-curing adhesives, and the cured product has excellent performance, high aging reliability, and a wide range of applications;

[0033] The absorption wavelength range is wide, and curing under long wavelength light source can be achieved. DETAILED DESCRIPTION

[0034] The following specific embodiments illustrate the implementation of the present invention, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the present invention will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this invention are limited to this implementation. On the contrary, the purpose of introducing the invention in conjunction with the implementation is to cover other options or modifications that may extend based on the claims of the present invention. In order to provide a deep understanding of the present invention, the following description will include many specific details. The present invention can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present invention, some specific details will be omitted in the description. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0035] Synthesis example

[0036] Weigh 12.4 g of 4-vinyl-1-cyclohexene-1,2-epoxy and 200 g of side hydrogenated silicone oil to make a solution, mix the solution of 4-vinyl-1-cyclohexene-1,2-epoxy and the platinum catalyst evenly, then heat to 40°C, add the side hydrogenated silicone oil dropwise, control the dropping speed, and complete the dropping within 30 min. During the dropping process, control the temperature not to exceed 60°C. After the dropping is completed, heat to 80°C and react for two hours to obtain an organosilicon-modified alicyclic epoxy resin, wherein the content of the platinum catalyst in the reaction system (4-vinyl-1-cyclohexene-1,2-epoxy and side hydrogenated silicone oil) is 10 ppm.

[0037] Example 1

[0038] Accurately weigh the following raw materials: CELLOXIDE 2021P 45g, the above-synthesized organosilicon-modified alicyclic epoxy resin 17g, OXT-221 19g, rosin ester diol (molecular weight 3000) 12g, rosin phenol 8g, 9,10-dibutoxyanthracene 1.5g, IRGACURE 261 0.5g, IRGACURE 262 0.5g; add the above components into a double planetary power mixer in turn, evacuate to a vacuum degree of -0.08MPa, stir at 500 rpm for 2 hours, stir evenly, let it stand naturally to room temperature, and seal and package.

[0039] Example 2

[0040] Accurately weigh the following raw materials: 50 g of CELLOXIDE 2021P, 12 g of the above-synthesized organosilicon-modified alicyclic epoxy resin, 18 g of OXT-212, 12 g of rosin ester diol (molecular weight 3000), 8 g of rosin phenol, 0.5 g of benzoin methyl ether, 0.5 g of IRGACURE 250, and 0.3 g of IRGACURE 262; add the above components into a double planetary power mixer in sequence, evacuate to a vacuum degree of -0.05 MPa, stir at 750 rpm for 1 hour, stir evenly, let it dry naturally to room temperature, and seal and package.

[0041] Example 3

[0042] Accurately weigh the following raw materials: 30 g of CELLOXIDE 2081, 25 g of the above-synthesized organosilicon-modified alicyclic epoxy resin, 15 g of OXT-121, 20 g of rosin ester diol (molecular weight 4000), 10 g of rosin phenol, 1 g of benzoyl peroxide, 0.2 g of IRGACURE 262, and 0.1 g of IRGACURE 261; add the above components into a double planetary power mixer in sequence, evacuate to a vacuum degree of -0.06 MPa, stir at 700 rpm for 1.5 hours, stir evenly, let it naturally cool to room temperature, and seal and package.

[0043] Example 4

[0044] Accurately weigh the following raw materials: 55g of S-60, 19g of the above-synthesized organosilicon-modified alicyclic epoxy resin, 10g of OXT-121, 6g of rosin ester diol (molecular weight 2000), 10g of rosin phenol, 0.8g of 4,4'-bis(diethylamino)benzophenone, 0.5g of IRGACURE 262, and 0.4g of IRGACURE 250; add the above components into a double planetary power mixer in sequence, evacuate to a vacuum degree of -0.07MPa, stir at 800 rpm for 1 hour, stir evenly, let it stand naturally to room temperature, and seal and package.

[0045] Example 5

[0046] Accurately weigh the following raw materials: CELLOXIDE 2081 40g, the above-synthesized organosilicon-modified alicyclic epoxy resin 18g, OXT-212 17g, rosin ester diol (molecular weight 3000) 20g, rosin phenol 5g, Trigonox B 0.9g, IRGACURE 261 0.7g, IRGACURE 262 0.5g; add the above components into a double planetary power mixer in sequence, evacuate to a vacuum degree of -0.08MPa, stir at 1000 rpm for 0.5 hour, stir evenly, let it stand naturally to room temperature, and seal and package.

[0047] Comparative Example 1

[0048] Accurately weigh the following raw materials: CELLOXIDE 2021P 45g, MBS 15g, OXT-221 19g, polycaprolactone diol 12g, 9,10-dibutoxyanthracene 1.5g, IRGACURE 261 1.5g; add the above components into a double planetary power mixer in turn, evacuate to a vacuum degree of -0.08MPa, stir at 500 rpm for 2 hours, stir evenly, let it dry naturally to room temperature, and seal it for packaging.

[0049] MBS resin is a terpolymer of methyl methacrylate (M), butadiene (B) and styrene (S).

[0050] Comparative Example 2

[0051] Accurately weigh the following raw materials: CELLOXIDE 2021P 55g, polycaprolactone diol 21g, OXT-22115g, 9,10-dibutoxyanthracene 1.5g, IRGACURE 250 1.5g; add the above components into a double planetary power mixer in turn, evacuate to a vacuum degree of -0.08MPa, stir at 500 rpm for 2 hours, stir evenly, let it naturally cool to room temperature, and seal it for packaging.

[0052] Comparative Example 3

[0053] Accurately weigh the following raw materials: CELLOXIDE 2021P 45g, silicone-modified ordinary aliphatic epoxy resin 17g, OXT-221 19g, rosin ester diol (molecular weight 3000) 12g, rosin phenol 8g, 9,10-dibutoxyanthracene 1.5g, IRGACURE 261 0.5g, IRGACURE 262 0.5g; add the above components into a double planetary power mixer in turn, evacuate to a vacuum degree of -0.08MPa, stir at 500 rpm for 2 hours, stir evenly, let it dry naturally to room temperature, and seal and package;

[0054] The alicyclic structure of the organosilicon-modified common aliphatic epoxy resin is on the main chain.

[0055] The performance of the cationic epoxy resin photocuring adhesives prepared in the embodiments and comparative examples was tested by the following tests.

[0056] Performance Testing

[0057] Curing light source 1 (UV curing): 365nm LED lamp, light intensity 500mW / cm 2 , irradiate for 1 minute to cure Light source 2 (visible light curing): 470nm LED lamp, light intensity 500mW / cm 2 , Modulus after irradiation for 3 minutes: DMA test.

[0058] Shear strength and tensile strength: tested by universal testing machine.

[0059] Drop performance test: drop from a height of 1.8m 50 times to determine whether it cracks.

[0060] The test results are shown in Table 1.

[0061] Table 1 Performance comparison test results

[0062]

[0063] Among them, shear strength 1 is the performance data tested after the photocuring adhesive is used to bond polycarbonate (PC) and ink, and shear strength 2 is the performance data tested after the photocuring adhesive is used to bond polycarbonate (PC) and copper; modulus, tensile strength, elongation, curing property at 470nm, and drop performance are all the properties of the photocuring adhesive after curing; in the drop performance, "OK" means that the photocuring adhesive has no cracks, and "NG" means that the photocuring adhesive has cracks.

[0064] The performance data of the embodiments in Table 1 are all tested under the condition that the cationic epoxy resin light-curing adhesive is fully cured. After the curing test, the cationic epoxy resin light-curing adhesive of each embodiment is tested under two curing conditions (i.e., 365nm LED light, light intensity 500mW / cm 2 , irradiated for 1 minute with 470nm LED light, light intensity 500mW / cm 2 , irradiation for 3 minutes) can be completely cured, and there is no significant difference in performance; while the light-curing adhesives in the comparative examples can only be cured under 365nm LED light with a light intensity of 500mW / cm 2 , cured under the curing conditions of 1 minute of irradiation, and cured under the conditions of 470nm LED light, light intensity 500mW / cm 2 Therefore, the performance data of Table 1, the performance data of Examples 1 to 5 are obtained by irradiating with a 470nm LED lamp with a light intensity of 500mW / cm 2 , measured after 3 minutes of curing; Comparative Examples 1-3 were cured by 365nm LED light, light intensity 500mW / cm 2 , measured after curing for 1 minute.

[0065] It can be seen from the results in Table 1 that, compared with the existing common cationic photocuring adhesive, the cationic epoxy resin photocuring adhesive of the present invention has high adhesion and high elongation as well as higher shear strength, and has excellent drop performance, and can be cured under the irradiation of a long wavelength light source represented by 470nm, and has a long absorption range.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cationic epoxy resin photocuring adhesive, characterized in that: The composition comprises the following components by weight percentage: 25-55% alicyclic epoxy resin, 10-25% organosilicon-modified alicyclic epoxy resin, 10-25% oxetane, 5-20% rosin ester diol, 5-10% adhesion promoter, 0.3-3% sensitizer, and 0.1-2% photoacid generator; The organosilicon-modified alicyclic epoxy resin has a structural formula shown in formula (I): （I） Wherein, b≥3, and a and b are both integers.

2. The cationic epoxy resin photocuring adhesive according to claim 1, characterized in that: The organosilicon-modified alicyclic epoxy resin is prepared by the following method: 4-vinyl-1-cyclohexene-1,2-epoxy and a platinum catalyst are uniformly mixed and heated, hydrogenated silicone oil is added dropwise, the dropping speed and the reaction temperature are controlled, the reaction temperature does not exceed 60° C., the dropping is completed, the temperature is increased and the reaction is carried out to obtain the organosilicon-modified alicyclic epoxy resin.

3. The cationic epoxy resin photocuring adhesive according to claim 1, characterized in that: The weight average molecular weight of the rosin ester diol is 2000-4000, and the rosin ester diol has a structural formula shown in formula (II): (II).

4. The cationic epoxy resin photocuring adhesive according to claim 1, characterized in that: The adhesion promoter is rosin phenol, having the structural formula shown in formula (III): (III).

5. The cationic epoxy resin photocuring adhesive according to claim 1, characterized in that: The sensitizer is any one or more of anthracene derivatives, benzoin derivatives, benzophenone and its derivatives, acetophenone and its derivatives, methyl o-benzoylbenzoate, and peroxide.

6. The cationic epoxy resin photocuring adhesive according to any one of claims 1 to 5, characterized in that: The photoacid generator is any one or more of an aromatic diazonium salt, a triarylsulfonium salt, a diaryliodonium salt, and an aromatic ferrocenium salt.

7. A method for preparing the cationic epoxy resin photocuring adhesive according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: weighing alicyclic epoxy resin, silicone-modified alicyclic epoxy resin, oxetane, rosin ester diol, adhesion promoter, sensitizer and photoacid generator, adding them into a mixer in sequence, evacuating to a vacuum degree of -0.08 to -0.05 MPa, controlling the rotation speed to 500 to 1000 r / min, stirring for 0.5 to 2 hours, naturally airing to room temperature, and sealing and packaging.

8. Use of the cationic epoxy resin photocuring adhesive according to any one of claims 1 to 6 in bonding electronic materials, characterized in that: The cationic epoxy resin light-curing adhesive is coated on the electronic material and placed under a light source for irradiation and curing.

9. The use of the cationic epoxy resin photocuring adhesive in bonding electronic materials according to claim 8, characterized in that: The electronic material is a copper substrate, and the wavelength of the light source is 365-470nm.

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