Single-component photo-thermal dual-curing epoxy adhesive

Abstract

The single-component photo-thermal dual-curing epoxy adhesive is prepared from the following raw materials in parts by weight: 100 parts of acrylic acid / polyurethane dual-modified epoxy resin, 10 to 40 parts of low-viscosity epoxy resin, 8 to 30 parts of epoxy curing agent, 30 to 300 parts of inorganic filler, 2 to 30 parts of dispersing agent and 0.25 to 5 parts of photoinitiator. The light curing agent has good light curing activity, high toughness and excellent high and low temperature resistance, and other properties are basically not affected; the photoinitiator can participate in the curing reaction in the system, so that the problem that the mechanical property and the adhesive property of the adhesive are reduced due to initiator molecule migration is avoided; the epoxy adhesive for semiconductor packaging is simple in preparation process, flexible in curing process and small in curing shrinkage, meets the weather resistance requirement of semiconductor packaging, and is feasible in industrial application.

Description

Technical Field

[0001] The invention relates to an epoxy adhesive, in particular to a light-heat dual-curing epoxy adhesive. Background Art

[0002] Epoxy adhesives have a wide range of application scenarios in the semiconductor industry due to their excellent bonding strength, electrical insulation, chemical corrosion resistance and thermal stability, such as chip packaging and protection, thermal management solutions, component bonding and fixing, flip chip bottom filling, wafer-level packaging and 3D integration, etc. However, epoxy adhesives have shortcomings such as large curing shrinkage, high rigidity, high brittleness, and long curing time. With the development and progress of other technologies in the semiconductor industry, these shortcomings have become increasingly prominent and have become a key point that limits its application in the semiconductor industry, especially in the packaging field.

[0003] In recent years, photothermal dual-curing epoxy adhesives have become one of the key directions of industrial applications. Photothermal dual-curing epoxy adhesives can be quickly cured under ultraviolet light or LED light, and have the advantage of flexible curing process. For dark areas that are not exposed to light or areas that need more thorough curing, they can also be post-cured by heating to ensure the curing effect. It also has the advantage of small curing shrinkage, which can effectively reduce the stress applied to the packaged device and protect the bonded material from damage.

[0004] However, the existing photothermal dual-curing epoxy adhesives still have the weakness of large brittleness of the cured products of most epoxy adhesives. At the same time, the incompatibility of the photoinitiator system will cause more ion migration on the bonding surface, which will have a significant negative impact on the reliability and adhesion of the epoxy adhesive, and it is not resistant to cold and hot shocks. With the increasing demand for epoxy adhesives in the field of chip packaging, higher requirements are also placed on the curing characteristics, adhesion, curing shrinkage, strength, and toughness of epoxy adhesives. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a single-component light-heat dual-curing epoxy adhesive with good high and low temperature impact resistance.

[0006] The technical solution adopted by the present invention to solve the technical problem is as follows: a one-component light-heat dual-curing epoxy adhesive, the raw materials of which include, by weight: 100 parts of acrylic acid / polyurethane dual-modified epoxy resin, 10-40 parts of low-viscosity epoxy resin, 8-30 parts of epoxy curing agent, 30-300 parts of inorganic filler, 2-30 parts of dispersant, and 0.25-5 parts of photoinitiator; The acrylic / polyurethane double-modified epoxy resin is obtained by reacting a polyfunctional epoxy resin with a polyurethane prepolymer and an acrylic monomer in sequence; the mass ratio of the polyfunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomer is 100∶20~150∶5~50; The viscosity of the low-viscosity epoxy resin is 80 mPa·s~2800 mPa·s; the epoxy value of the low-viscosity epoxy resin is 0.1 eq / 100 g~0.9 eq / 100 g; The particle size of the inorganic filler is 5 nm~1000 nm; The photoinitiator is an amine anthracene compound.

[0007] Preferably, the preparation method of the acrylic / polyurethane double-modified epoxy resin includes: (1) After mixing the polyfunctional epoxy resin with a solvent, add the polyurethane prepolymer and add catalyst 1 for reaction; (2) Continuously add the acrylic monomer and add catalyst 2 for reaction; the transparent viscous liquid obtained after removing the solvent is the acrylic / polyurethane double-modified epoxy resin.

[0008] More preferably, the polyurethane prepolymer is an isocyanate group-terminated prepolymer.

[0009] Preferably, the mass ratio of the polyfunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomer is 100∶25~100∶12~25.

[0010] More preferably, the solvent is one or a combination of two or more of acetone, butanone, ethanol, methanol, n-hexane, n-pentane, n-octane, dimethyl sulfoxide, and dimethylformamide.

[0011] More preferably, in step (1), the reaction temperature is 80°C~200°C and the reaction time is 4 h~9 h.

[0012] More preferably, in step (2), the reaction temperature is 80°C~200°C and the reaction time is 4 h~9 h.

[0013] More preferably, the catalyst 1 is one or a combination of two or more of dibutyltin dilaurate, stannous octoate, lead octoate, cobalt octoate, iron octoate, zinc naphthenate, tetra-isobutyl titanate, p-toluenesulfonic acid, triethylamine, and triethylenediamine.

[0014] More preferably, the catalyst 2 is one or a combination of two or more of triphenylphosphine, triethylbenzylammonium bromide, tetrabutylammonium bromide, and 4-dimethylaminopyridine.

[0015] More preferably, the polyfunctional epoxy resin is: bisphenol A glycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether methane, triglycidyl-p-aminophenol, triglycidyl triisocyanate, tetraglycidyl diaminodiphenyl methane, tetraglycidyl xylylenediamine, tetraglycidyl-1,3-bis(aminomethyl)cyclohexylamine, or a composition of one or more of the above resins and their homologues and derivatives.

[0016] More preferably, the polyurethane prepolymer is a composition of one or more of polyether-modified polyisocyanate and polyester-modified polyisocyanate.

[0017] More preferably, the acrylic monomer is a composition of one or more of acrylic acid, methacrylic acid, acrylic anhydride, and acetic acrylic anhydride.

[0018] Preferably, the low-viscosity epoxy resin is a composition of one or more of bisphenol S epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, and linear phenolic epoxy resin.

[0019] Preferably, the epoxy curing agent is a composition of one or more of dicyandiamide, imidone, melamine, organic acid hydrazide, aromatic diazonium salt, and microencapsulated curing agent.

[0020] Preferably, the photoinitiator is a composition of one or more of 2,6-diaminoanthracene, 9-anilinoanthracene, anthracen-9-ylmethylamine, 9H-xanthen-9-amine, 9-aminoanthracene, (11R,12R)-9,10-dihydro-9,10-ethylenedianthracene-11,12-diamine, 9,10-bis[N-(m-tolyl)phenylamino]anthracene, 9,10-bis[N-(p-tolyl)anilino]anthracene, 2,6-diaminoanthraquinone, and 9,10-bis(N,N-dimethylaminomethyl)anthracene.

[0021] Preferably, by weight, the raw materials of the one-component photo-thermal dual-curing epoxy adhesive include: 100 parts of acrylic / polyurethane dual-modified epoxy resin, 15 - 35 parts of low-viscosity epoxy resin, 10 - 25 parts of epoxy curing agent, 50 - 250 parts of inorganic filler, 5 - 20 parts of dispersant, and 0.5 - 3 parts of photoinitiator.

[0022] Preferably, the inorganic filler is spherical silica powder.

[0023] Preferably, the dispersant is a non-solvent type high molecular weight wetting dispersant.

[0024] Preferably, the raw materials further include a colorant, and the dosage is less than 10 wt% of the acrylic / polyurethane dual-modified epoxy resin.

[0025] More preferably, the colorant is one or more compositions of carbon black, iron oxide red, titanium dioxide, phthalocyanine green, etc.

[0026] Preferably, for the one-component photo-thermo dual-curing epoxy adhesive, the preparation method includes the following steps: (a) Preparation of the main material: Mix the low-viscosity epoxy resin and the acrylic / polyurethane dual-modified epoxy resin evenly, add inorganic fillers and a dispersant, mix and grind, defoam after mixing evenly, and store the obtained main material below 30 °C. (b) Preparation of the adhesive: Add the remaining raw materials to the main material, mix and grind under vacuum conditions, filter and discharge after mixing evenly.

[0027] More preferably, the temperature when the low-viscosity epoxy resin and the acrylic / polyurethane dual-modified epoxy resin are mixed is 80 °C to 180 °C.

[0028] More preferably, after adding the inorganic fillers and the dispersant, the temperature for mixing and grinding is 70 °C to 110 °C.

[0029] More preferably, during the preparation process of the adhesive in step (b), the temperature is below 30 °C.

[0030] More preferably, the pressure condition for defoaming is 0.06 MPa to 0.2 MPa.

[0031] More preferably, the vacuum condition is that the air pressure is below -0.08 MPa.

[0032] The present invention has the following beneficial effects: (1) The present invention has good photo-curing activity, high toughness and excellent high and low temperature resistance; compared with the existing adhesives, the performance in other aspects is basically not affected. (2) The photoinitiator adopted in the present invention can participate in the curing reaction in the system of the present invention, avoiding the problem of the decline in the mechanical properties and bonding properties of the adhesive caused by the migration of the initiator molecules. (3) The present invention has a flexible curing process, small curing shrinkage, meets the weather resistance requirements of semiconductor packaging, and is a kind of epoxy adhesive for semiconductor packaging that is feasible in industrial applications.

[0033] In addition to the purposes, features and advantages described above, the present invention has other purposes, features and advantages. The present invention will be further described in detail below. Detailed embodiments

[0034] To make the objectives, solutions, and beneficial technologies of the present invention clearer, the present invention will be further described in detail below with reference to embodiments. It should be noted that the embodiments described in this specification are only for explaining the present invention and not for limiting the present invention.

[0035] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form a range not explicitly recited; and any lower limit can be combined with other lower limits to form a range not explicitly recited, and similarly any upper limit can be combined with any other upper limit to form a range not explicitly recited. In addition, although not explicitly recited, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be used as its own lower or upper limit and combined with any other point or single value or combined with other lower or upper limits to form a range not explicitly recited.

[0036] In the description herein, it should be noted that unless otherwise specified, "above" and "below" include the recited number, "multiple" in "one or more" means two or more, and "multiple" in "one or more" means two or more.

[0037] An embodiment of the present invention provides a one-component photo-thermal dual-curing epoxy adhesive. By weight, the raw materials include: 100 parts of acrylic / polyurethane dual-modified epoxy resin, 10 - 40 parts of low-viscosity epoxy resin, 8 - 30 parts of epoxy curing agent, 30 - 300 parts of inorganic filler, 2 - 30 parts of dispersant, and 0.25 - 5 parts of photoinitiator. The acrylic / polyurethane dual-modified epoxy resin is obtained by reacting a polyfunctional epoxy resin with a polyurethane prepolymer and an acrylic monomer in sequence; the mass ratio of the polyfunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomer is 100∶20 - 150∶5 - 50. The viscosity of the low-viscosity epoxy resin is 80 mPa·s - 2800 mPa·s; the epoxy value of the low-viscosity epoxy resin is 0.1 eq / 100 g - 0.9 eq / 100 g. The particle size of the inorganic filler is 5 nm - 1000 nm. The photoinitiator is an amine anthracene compound.

[0038] In terms of photo-thermal dual curing, in the embodiments of the present invention, by introducing an amine-anthracene photoinitiator, it has both photo-initiation and thermal-initiation curing effects: on the one hand, the anthracene structure can generate photo-free radicals under photo-initiation, thereby promoting the photocuring of double bonds in the acrylic / polyurethane double-modified epoxy resin; on the other hand, the amine structure endows it with the function of an accelerator, and under thermal curing conditions, it participates in and promotes the reaction between the epoxy curing agent and the epoxy group; the photoinitiator participates in the thermal curing reaction, effectively avoiding the phenomenon of molecular migration after curing caused by the non-participation of traditional photoinitiators in the thermal curing reaction, and effectively improving the reliability and adhesiveness of the epoxy adhesive.

[0039] In terms of the design of the main resin, in the embodiments of the present invention, by the method of acrylic / polyurethane double modification, acrylic and polyurethane groups are introduced into the molecular structure of the epoxy resin at the same time; the introduction of the acrylic group can ensure the photocuring activity, and the polyurethane group effectively improves the molecular flexibility of the cured product obtained by traditional epoxy thermal curing and acrylic photocuring, and enhances the toughness and high and low temperature resistance of the epoxy adhesive.

[0040] In the three-dimensional network structure design of the epoxy resin of the present invention, low-viscosity epoxy resins such as bisphenol S type, bisphenol A type, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, and linear phenolic epoxy resin are also selected. During the photocuring process, the low-viscosity epoxy resin and the photocuring components form an interpenetrating network structure of mutual crosslinking. The whole system has good compatibility, and the added fillers are also evenly dispersed in the matrix, thereby not only improving the toughness of the epoxy adhesive, but also basically not affecting other properties.

[0041] The one-component photo-thermal dual-curing epoxy adhesive provided by the embodiments of the present invention has the following advantages: (1) The embodiments of the present invention have good photocuring activity, high toughness, and excellent high and low temperature resistance; compared with the existing adhesives, other properties are basically not affected; (2) The photoinitiator used in the embodiments of the present invention can participate in the curing reaction in the system of the present invention, avoiding the problem of the decrease in the mechanical properties and bonding properties of the adhesive caused by the migration of the initiator molecules; (3) The curing process available in the embodiments of the present invention is flexible and has small curing shrinkage, meeting the weather resistance requirements of semiconductor packaging, and is a kind of epoxy adhesive for semiconductor packaging that is feasible in industrial applications.

[0042] In the embodiments of the present invention, the preparation method of the acrylic / polyurethane double-modified epoxy resin includes: (1) After mixing the polyfunctional epoxy resin with the solvent, add the polyurethane prepolymer and add catalyst 1 for reaction; (2) Continuously add acrylic monomers and react with catalyst 2; the transparent viscous liquid obtained after removing the solvent is the acrylic / polyurethane double-modified epoxy resin.

[0043] In some embodiments of the present invention, the polyurethane prepolymer is an isocyanate-terminated prepolymer.

[0044] In the embodiments of the present invention, the mass ratio of the polyfunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomers is 100∶25~100∶12~25.

[0045] The removal of the solvent can be achieved by conventional methods such as vacuum distillation.

[0046] In some embodiments of the present invention, the addition amount of each catalyst is 0.05%~1% of the total mass of the reactants.

[0047] In some embodiments of the present invention, the solvent is one or a combination of two or more of acetone, butanone, ethanol, methanol, n-hexane, n-pentane, n-octane, dimethyl sulfoxide, and dimethylformamide.

[0048] In some embodiments of the present invention, in step (1), the reaction temperature is 80°C~200°C and the reaction time is 4h~9h.

[0049] In some embodiments of the present invention, in step (2), the reaction temperature is 80°C~200°C and the reaction time is 4h~9h.

[0050] In some embodiments of the present invention, the catalyst 1 is one or a combination of two or more of dibutyltin dilaurate, stannous octoate, lead octoate, cobalt octoate, iron octoate, zinc naphthenate, tetra-isobutyl titanate, p-toluenesulfonic acid, triethylamine, and triethylenediamine.

[0051] In some embodiments of the present invention, the catalyst 2 is one or a combination of two or more of triphenylphosphine, triethylbenzylammonium bromide, tetrabutylammonium bromide, and 4-dimethylaminopyridine.

[0052] In some embodiments of the present invention, the polyfunctional epoxy resin is: bisphenol A diglycidyl ether, tetraphenyl diglycidyl ether ethane, triphenyl diglycidyl ether methane, tris-glycidyl-p-aminophenol, tris-glycidyl triisocyanate, tetrakis-glycidyl diaminodiphenylmethane, tetrakis-glycidyl xylylenediamine, tetrakis-glycidyl-1,3-bis(aminomethyl)cyclohexane, and one or a combination of two or more of the above resins and their homologues and derivatives.

[0053] In some embodiments of the present invention, the polyurethane prepolymer is one or a combination of two or more of polyether-modified polyisocyanate and polyester-modified polyisocyanate.

[0054] In some embodiments of the present invention, the acrylic monomer is one or a combination of two or more of acrylic acid, methacrylic acid, acrylic anhydride, and acetic acrylic anhydride.

[0055] In an embodiment of the present invention, the low-viscosity epoxy resin is one or a combination of two or more of bisphenol S epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, and linear phenolic epoxy resin.

[0056] In an embodiment of the present invention, the epoxy curing agent is one or a combination of two or more of dicyandiamide, imidone, melamine, organic acid hydrazide, aromatic diazonium salt, and microencapsulated curing agent.

[0057] In an embodiment of the present invention, the photoinitiator is one or a combination of two or more of 2,6-diaminoanthracene, 9-anilinoanthracene, anthracen-9-ylmethylamine, 9H-xanthen-9-amine, 9-aminoanthracene, (11R,12R)-9,10-dihydro-9,10-ethylenedianthracene-11,12-diamine, 9,10-bis[N-(m-tolyl)phenylamino]anthracene, 9,10-bis[N-(p-tolyl)anilino]anthracene, 2,6-diaminoanthraquinone, and 9,10-bis(N,N-dimethylaminomethyl)anthracene.

[0058] In an embodiment of the present invention, by weight, the raw materials of the one-component photo-thermal dual-curing epoxy adhesive include: 100 parts of acrylic / polyurethane dual-modified epoxy resin, 15-35 parts of low-viscosity epoxy resin, 10-25 parts of epoxy curing agent, 50-250 parts of inorganic filler, 5-20 parts of dispersant, and 0.5-3 parts of photoinitiator.

[0059] In an embodiment of the present invention, the inorganic filler is spherical silica powder.

[0060] In an embodiment of the present invention, the dispersant is a non-solvent type high molecular weight wetting dispersant.

[0061] In an embodiment of the present invention, the raw materials further include a colorant, and the dosage is less than 10 wt% of the acrylic / polyurethane dual-modified epoxy resin.

[0062] In some embodiments of the present invention, the colorant is one or a combination of carbon black, iron red, titanium dioxide, and phthalocyanine green.

[0063] In an embodiment of the present invention, the preparation method of the one-component photo-thermal dual-curing epoxy adhesive includes the following steps: (a)Preparation of the main material: Mix the low-viscosity epoxy resin and the acrylic / polyurethane dual-modified epoxy resin evenly, add inorganic filler and dispersant, mix and grind, defoam after mixing evenly, and store the obtained main material below 30°C; (b)Preparation of the adhesive: Add the remaining raw materials to the main material, mix and grind under vacuum conditions, filter and discharge after mixing evenly.

[0064] To avoid premature photoinitiation, the preparation of the adhesive in step (b) needs to be carried out in a non-ultraviolet light environment.

[0065] In some embodiments of the present invention, the temperature when the low-viscosity epoxy resin is mixed with the acrylic / polyurethane dual-modified epoxy resin is 80°C to 180°C.

[0066] In some embodiments of the present invention, after adding the inorganic filler and dispersant, the temperature for mixing and grinding is 70°C to 110°C.

[0067] In some embodiments of the present invention, during the preparation of the adhesive in step (b), the temperature is below 30°C.

[0068] In some embodiments of the present invention, the pressure condition for defoaming is 0.06 MPa to 0.2 MPa.

[0069] In some embodiments of the present invention, the vacuum condition is that the air pressure is below -0.08 MPa.

[0070] Examples The following examples more specifically describe the content disclosed in the present invention. These examples are only for illustrative purposes, because various modifications and changes within the scope of the present invention are obvious to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are based on weight. Unless otherwise stated, all reagents used in the examples can be obtained through conventional commercial channels or synthesized according to conventional methods, and can be used directly without further treatment. Unless otherwise stated, the instruments used in the examples can be obtained through conventional commercial channels.

[0071] Example 1 The one-component photo-thermal dual-curing epoxy adhesive of this example includes the following raw materials by weight: Acrylic / polyurethane dual-modified epoxy resin (self-made) 100 parts; Low-viscosity epoxy resin (bisphenol F epoxy resin) 30 parts; Epoxy curing agent (melamine) 20 parts; Inorganic filler (silica powder, spherical, 500 nm) 180 parts; Dispersant (BYK-110) 16 parts; Colorant (carbon black) 4 parts; Photoinitiator (2,6-diaminoanthracene) 1 part.

[0072] Among them, the epoxy value of the low-viscosity epoxy resin (bisphenol F epoxy resin) is 0.42 eq / 100g, and the viscosity is 1200 mPa·s.

[0073] The self-made acrylic / polyurethane double-modified epoxy resin of this example is obtained by reacting a polyfunctional epoxy resin (bisphenol A glycidyl ether, epoxy value 0.50 eq / 100g) with a polyurethane prepolymer (PTMEG-IPDI polyurethane prepolymer, about 1000 molecular weight) and an acrylic monomer (methacrylic acid) in sequence.

[0074] The main chemical reactions involved in the preparation process of the above acrylic / polyurethane double-modified epoxy resin are as follows: .

[0075] The specific preparation process of the acrylic / polyurethane double-modified epoxy resin is as follows: (1) Add xylene and 100 g of polyfunctional epoxy resin to a three-necked flask, mix evenly at 80 °C; slowly drop 80 g of polyurethane prepolymer, add a catalyst (dibutyltin dilaurate) after mixing evenly, and then continue to react for 5 h; (2) Add 14 g of methacrylic acid, mix evenly, add a catalyst (4-dimethylaminopyridine), and continue to react for 5 h; after the reaction is completed, distill off the solvent under reduced pressure, centrifuge, and the obtained transparent viscous liquid is the acrylic / polyurethane double-modified epoxy resin.

[0076] The one-component photo-thermal dual-curing epoxy adhesive of this example is obtained by mixing the raw materials, and the specific preparation method is: (a) Preparation of the main material: Add low-viscosity epoxy resin and acrylic / polyurethane double-modified epoxy resin to a planetary power mixer, mix evenly at 90 °C, then add inorganic filler and dispersant, control the material temperature at 90 °C, stir at high speed for 60 min, and then grind through a two-pass three-roll mill to make the filler disperse more evenly, defoam under a pressure of 0.1 MPa, and then cool the material to below 20 °C for standby; (b) Preparation of the adhesive: Add the remaining raw materials to the main material, stir under vacuum (-0.08 MPa or below) for 60 min, control the material temperature below 20 °C and in a non-ultraviolet light environment throughout the process, grind, and finally filter and package the material with a press.

[0077] Example 2 The one-component photo-thermal dual-curing epoxy adhesive of this embodiment, by weight, comprises the following raw materials: Acrylic acid / polyurethane dual-modified epoxy resin (self-made) 100 parts; Low-viscosity epoxy resin (bisphenol A epoxy resin) 18 parts; Epoxy curing agent (dicyandiamide) 16 parts; Inorganic filler (silica powder, spherical, 500 nm) 200 parts; Dispersant (BYK-110) 8 parts; Colorant (iron red) 2 parts; Photoinitiator (9,10-bis[N-(m-tolyl)phenylamino]anthracene) 1.3 parts.

[0078] Among them, the epoxy value of the low-viscosity epoxy resin (bisphenol A epoxy resin) is 0.51 eq / 100 g, and the viscosity is 300 mPa·s.

[0079] The self-made acrylic acid / polyurethane dual-modified epoxy resin of this embodiment is obtained by successively reacting a polyfunctional epoxy resin (tetraglycidyl diaminodiphenylmethane) with a polyurethane prepolymer (polyether polyol-MDI hydroxyl-containing polyurethane prepolymer (molecular weight about 3000)) and an acrylic monomer (acrylic acid); the specific preparation process is as follows: (1) Add a solvent (toluene) and 82 g of tetraglycidyl diaminodiphenylmethane to a three-necked flask, mix evenly at 100 °C; slowly dropwise add 40 g of polyether polyol-MDI hydroxyl-containing polyurethane prepolymer (molecular weight 3000), after mixing evenly, dropwise add 0.5 g of a catalyst (tetraisobutyl titanate), and then continue to react for 6 h; (2) Then add 18 g of acrylic acid, mix evenly, dropwise add a catalyst (tetrabutylammonium bromide), and continue to react for 4 h; after the reaction is completed, remove the solvent by reduced pressure distillation, centrifuge, and the obtained transparent viscous liquid is the acrylic acid / polyurethane dual-modified epoxy resin.

[0080] The one-component photo-thermal dual-curing epoxy adhesive of this embodiment is obtained by mixing the various raw materials, and the specific preparation method is as follows: (a) Preparation of the main material: Add the low-viscosity epoxy resin and the acrylic acid / polyurethane dual-modified epoxy resin to a planetary power mixer, mix evenly at 80 °C, then add the inorganic filler and the dispersant, control the material temperature at 80 °C, stir at high speed for 60 min, then grind through a two-pass three-roll mill to make the filler disperse more evenly, carry out degassing under a pressure of 0.1 MPa, and then cool the material to below 20 °C for standby; (b) Preparation of the adhesive: The remaining raw materials are added to the main raw materials, and stirred under vacuum (below -0.08 MPa) for 45 min. The temperature of the materials is controlled below 20 °C throughout the process and in a non-ultraviolet light environment. After grinding, it is finally filtered through a pressing machine and packaged after discharging.

[0081] Example 3 The raw materials of the one-component photo-thermal dual-curing epoxy adhesive in this example include, by weight: Acrylic / polyurethane dual-modified epoxy resin (self-made) 100 parts; Low-viscosity epoxy resin (bisphenol F epoxy resin) 20 parts; Epoxy curing agent (melamine) 15 parts; Inorganic filler (silica powder, spherical, 800 nm) 200 parts; Dispersant (BYK-110) 8 parts; Colorant (carbon black) 4 parts; Photoinitiator (2,6-diaminoanthracene) 1 part.

[0082] Among them, the epoxy value of the low-viscosity epoxy resin (bisphenol F epoxy resin) is 0.42 eq / 100 g, and the viscosity is 1200 mPa·s.

[0083] The self-made acrylic / polyurethane dual-modified epoxy resin in this example is obtained by reacting a polyfunctional epoxy resin (triphenyl glycidyl ether methane) with a PTMEG-TDI hydroxyl-containing polyurethane prepolymer (molecular weight about 2000) and an acrylic monomer (methacrylic acid) in sequence. The specific preparation process is as follows: (1) Add a solvent (toluene) and 55 g of polyfunctional epoxy resin to a three-necked flask, and mix evenly at 80 °C; slowly dropwise add 15 g of polyurethane prepolymer, add 0.1 g of catalyst (stannous octoate) after mixing evenly, and then continue to react for 4 h; (2) Add 8 g of acrylic monomer, mix evenly, add 0.05 g of catalyst (triethylbenzylammonium bromide), and continue to react for 5 h; after the reaction is completed, the solvent is removed by distillation under reduced pressure, and centrifuged to obtain a transparent viscous liquid, which is the acrylic / polyurethane dual-modified epoxy resin.

[0084] The one-component photo-thermal dual-curing epoxy adhesive in this example is obtained by mixing the raw materials. The specific preparation method is as follows: (a)Preparation of the main material: Add low-viscosity epoxy resin and acrylic / polyurethane double-modified epoxy resin into a planetary power mixer, mix evenly at 85°C, then add inorganic filler and dispersant, control the material temperature at 90°C, stir at high speed for 60 min, and then grind through a three-roll mill twice to make the filler more evenly dispersed. Debubble under a pressure of 0.2 MPa, and then cool the material to below 20°C for standby; (b)Preparation of the adhesive: Add the remaining raw materials to the main material, stir under vacuum (below -0.08 MPa) for 60 min, control the material temperature below 20°C throughout the process and in a non-ultraviolet light environment, grind, and finally filter and discharge the material with a pressing machine for packaging.

[0085] Comparative Example 1 The raw materials and preparation method of the adhesive in this comparative example are basically the same as those in Example 1, except that the acrylic / polyurethane double-modified epoxy resin is not prepared, but the raw materials of the acrylic / polyurethane double-modified epoxy resin - bisphenol A glycidyl ether, PTMEG-IPDI polyurethane prepolymer, and methacrylic acid are directly used as the raw materials of the adhesive in the original proportion.

[0086] Comparative Example 2 The raw materials and preparation method of the adhesive in this comparative example are basically the same as those in Example 1, except that the acrylic / polyurethane double-modified epoxy resin is not used, but bisphenol A glycidyl ether in Example 1 is used instead.

[0087] Comparative Example 3 The raw materials and preparation method of the adhesive in this comparative example are basically the same as those in Example 1, except that the photoinitiator used is replaced with the commonly used Irgacure 2959 photoinitiator in the art.

[0088] Comparative Example 4 The raw materials and preparation method of the adhesive in this comparative example are basically the same as those in Example 1, except that the low-viscosity epoxy resin (bisphenol F epoxy resin) is replaced with the commonly used active diluent trimethylolpropane triacrylate (TMPTA) in photocurable adhesives.

[0089] Detection and analysis For the adhesives of each example and comparative example, as well as the single-component photo-thermal dual-curing epoxy adhesive product (SUNSTAR Shengshida 1122) on the market. Perform performance tests on various indicators. The curing conditions are as follows: primary curing (light): 365 nm LED lamp, 1500 mW / cm 2 , 10 s; secondary curing (heat): 80°C / 60 min, 100°C / 30 min; The test results of the examples and commercial products are shown in Table 1, and the test results of the comparative examples are shown in Table 2. The test standards adopted are also shown in Table 1 and Table 2.

[0090] As can be seen from Table 1, compared with the commercially available products, the adhesives of Examples 1 to 3 of the present invention have a certain improvement in bending strength and a significant improvement in shear strength. In particular, the shear strength after thermal shock resistance and the shear strength after the double 85 test are basically more than twice that of the commercially available products.

[0091] Table 1 Performance test results of adhesives of each example and commercially available products

[0092] Combined with Table 1 and Table 2, it can be seen that in the comparative examples, in Comparative Example 3 where the photoinitiator was replaced relative to Example 1, the shear strength, bending strength, shear strength after thermal shock resistance, and shear strength after the double 85 test are all better than those of the commercially available products, but there is still a large gap compared with Example 1. The synergistic effect between the components of the composition in the present invention is the key to the significant improvement of the shear strength of the present invention. In Comparative Example 4, the low-viscosity epoxy resin in the present invention was replaced with an active diluent commonly used in photocurable adhesives, which cannot form an interpenetrating network structure with the photocurable components, resulting in a decrease in performance compared with the examples of the present invention.

[0093] Table 2 Performance test results of adhesives of each comparative example

[0094] The description of the above examples is only used to help understand the method and its core idea of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A one-component epoxy adhesive with dual photo-thermal curing, characterized in that, By weight, the raw materials include: 100 parts of acrylic / polyurethane double-modified epoxy resin, 10 - 40 parts of low-viscosity epoxy resin, 8 - 30 parts of epoxy curing agent, 30 - 300 parts of inorganic filler, 2 - 30 parts of dispersant, and 0.25 - 5 parts of photoinitiator; The acrylic / polyurethane double-modified epoxy resin is obtained by reacting a polyfunctional epoxy resin with a polyurethane prepolymer and an acrylic monomer in sequence; the mass ratio of the polyfunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomer is 100∶20 - 150∶5 - 50; The viscosity of the low-viscosity epoxy resin is 80 mPa·s - 2800 mPa·s; the epoxy value of the low-viscosity epoxy resin is 0.1 eq / 100 g - 0.9 eq / 100 g; The particle size of the inorganic filler is 5 nm - 1000 nm; The photoinitiator is an amine anthracene compound.

2. The one-component epoxy adhesive with dual photo-thermal curing according to claim 1, characterized in that, The preparation method of the acrylic / polyurethane double-modified epoxy resin includes: (1) After mixing the polyfunctional epoxy resin with a solvent, add the polyurethane prepolymer and add catalyst 1 for reaction; (2) Continuously add the acrylic monomer and add catalyst 2 for reaction; the transparent viscous liquid obtained after removing the solvent is the acrylic / polyurethane double-modified epoxy resin; The polyurethane prepolymer is a terminal isocyanate group prepolymer; The mass ratio of the polyfunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomer is 100∶25 - 100∶12 - 25.

3. The one-component epoxy adhesive with dual photo-thermal curing according to claim 2, characterized in that, The solvent is one or a combination of two or more of acetone, butanone, ethanol, methanol, n-hexane, n-pentane, n-octane, dimethyl sulfoxide, and dimethylformamide; In step (1), the reaction temperature is 80°C - 200°C and the reaction time is 4 h - 9 h; In step (2), the reaction temperature is 80°C - 200°C and the reaction time is 4 h - 9 h; The catalyst 1 is one or a combination of two or more of dibutyltin dilaurate, stannous octoate, lead octoate, cobalt octoate, iron octoate, zinc naphthenate, tetra-isobutyl titanate, p-toluenesulfonic acid, triethylamine, and triethylenediamine; The catalyst 2 is one or a combination of two or more of triphenylphosphine, triethylbenzylammonium bromide, tetrabutylammonium bromide, and 4-dimethylaminopyridine.

4. The one-component epoxy adhesive with dual photo-thermal curing according to claim 2, characterized in that, The polyfunctional epoxy resin is: bisphenol A diglycidyl ether, tetraphenyl diglycidyl ether ethane, triphenyl diglycidyl ether methane, triglycidyl-p-aminophenol, triglycidyl triisocyanate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylylenediamine, tetraglycidyl-1,3,-bis(aminomethyl)cyclohexylamine, one or a combination of two or more of the above resins and their homologues and derivatives; The polyurethane prepolymer is one or a combination of two or more of polyether-modified polyisocyanate and polyester-modified polyisocyanate; The acrylic monomer is one or a combination of two or more of acrylic acid, methacrylic acid, acrylic anhydride, and acetic acrylic anhydride.

5. The one-component epoxy adhesive with dual photo-thermal curing according to any one of claims 1 to 4, characterized in that, The low-viscosity epoxy resin is one or a combination of two or more of bisphenol S epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, and linear phenolic epoxy resin; The epoxy curing agent is one or a combination of two or more of dicyandiamide, imidazolone, melamine, organic acid hydrazide, aromatic diazonium salt, and microencapsulated curing agent; The photoinitiator is one or a combination of two or more of 2,6-diaminoanthracene, 9-anilinoanthracene, anthracen-9-ylmethylamine, 9H-xanthen-9-amine, 9-aminoanthracene, (11R,12R)-9,10-dihydro-9,10-ethylenedianthracene-11,12-diamine, 9,10-bis[N-(m-tolyl)phenylamino]anthracene, 9,10-bis[N-(p-tolyl)anilino]anthracene, 2,6-diaminoanthraquinone, and 9,10-bis(N,N-dimethylaminomethyl)anthracene.

6. The one-component epoxy adhesive with dual photo-thermal curing according to claim 1, characterized in that, By weight, the raw materials include: 100 parts of acrylic / polyurethane double-modified epoxy resin, 15-35 parts of low-viscosity epoxy resin, 10-25 parts of epoxy curing agent, 50-250 parts of inorganic filler, 5-20 parts of dispersant, and 0.5-3 parts of photoinitiator; The inorganic filler is spherical silica powder; The dispersant is a non-solvent type high molecular weight wetting dispersant.

7. The one-component epoxy adhesive with dual photo-thermal curing according to claim 1, characterized in that, The raw materials further include a colorant, and the dosage is less than 10 wt% of the acrylic / polyurethane double-modified epoxy resin.

8. The one-component epoxy adhesive with dual photo-thermal curing according to claim 7, characterized in that, The colorant is one or a combination of carbon black, iron oxide red, titanium dioxide, and phthalocyanine green.

9. The one-component epoxy adhesive with dual photo-thermal curing according to any one of claims 1, 6, 7, and 8, characterized in that, The preparation method includes the following steps: (a) Preparation of the main material: Mix the low-viscosity epoxy resin and the acrylic / polyurethane double-modified epoxy resin evenly, add the inorganic filler and the dispersant, mix and grind, defoam after mixing evenly, and store the obtained main material at a temperature below 30°C; (b) Preparation of the adhesive: Add the remaining raw materials to the main material, mix and grind under vacuum conditions, filter and discharge after mixing evenly.

10. The one-component photo-thermal dual-curing epoxy adhesive according to claim 9, characterized in that, The temperature for mixing the low-viscosity epoxy resin and the acrylic / polyurethane double-modified epoxy resin is 80°C to 180°C; After adding the inorganic filler and the dispersant, the temperature for mixing and grinding is 70°C to 110°C; During the preparation process of the adhesive in step (b), the temperature is below 30°C; The pressure condition for defoaming is 0.06 MPa to 0.2 MPa; The vacuum condition is that the air pressure is below -0.08 MPa.

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