A one-component light-heat dual-curing epoxy adhesive

Abstract

A single-component photothermal dual-curing epoxy adhesive. The raw materials, calculated by weight, include: 100 parts of an acrylic / polyurethane dual-modified epoxy resin, 10-40 parts of a low-viscosity epoxy resin, 8-30 parts of an epoxy curing agent, 30-300 parts of an inorganic filler, 2-30 parts of a dispersant, and 0.25-5 parts of a photoinitiator. This adhesive exhibits excellent photocuring activity, high toughness, and excellent high- and low-temperature resistance, while maintaining other properties. The photoinitiator in this system participates in the curing reaction, avoiding the degradation of the adhesive's mechanical and bonding properties due to initiator molecular migration. The adhesive also offers a flexible curing process and minimal curing shrinkage, meeting the weather resistance requirements of semiconductor packaging. This makes it an industrially viable epoxy adhesive for semiconductor packaging.

Description

Technical Field

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

[0002] Epoxy adhesives, due to their excellent bond strength, electrical insulation, chemical resistance, and thermal stability, have a wide range of applications in the semiconductor industry, including chip packaging and protection, thermal management solutions, component bonding and fixing, flip-chip underfill, wafer-level packaging, and 3D integration. However, epoxy adhesives suffer from limitations such as large cure shrinkage, high rigidity, high brittleness, and long cure times. With the advancement of other semiconductor technologies, these limitations have become increasingly prominent, becoming key limitations in their application in the semiconductor industry, particularly in the packaging sector.

[0003] In recent years, dual-curing epoxy adhesives, both photothermal and optical, have become a key area of ​​industrial application. These adhesives cure rapidly under UV or LED light, offering a flexible curing process. For dark areas or those requiring a more thorough cure, they can be post-cured with heating to ensure optimal curing. They also exhibit minimal shrinkage upon cure, effectively reducing stress on encapsulated devices and protecting the bonded materials from damage.

[0004] However, existing dual-curing epoxy adhesives, such as photothermal and optical epoxy adhesives, still suffer from the brittle nature of most epoxy adhesives. Furthermore, the incompatibility of the photoinitiator system can cause significant ion migration on the bonding surface, significantly negatively impacting the reliability and adhesion of the epoxy adhesive, and making it vulnerable to thermal shock. With the increasing demand for epoxy adhesives in the chip packaging field, higher requirements are being placed on their curing characteristics, adhesion, cure shrinkage, strength, and toughness. 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;

[0007] The acrylic acid / polyurethane double-modified epoxy resin is obtained by sequentially reacting a multifunctional epoxy resin with a polyurethane prepolymer and an acrylic monomer; wherein the mass ratio of the multifunctional epoxy resin, the polyurethane prepolymer and the acrylic monomer is 100:20-150:5-50;

[0008] The viscosity of the low-viscosity epoxy resin is 80 mPa·s to 2800 mPa·s; the epoxy value of the low-viscosity epoxy resin is 0.1 eq / 100 g to 0.9 eq / 100 g;

[0009] The particle size of the inorganic filler is 5nm~1000nm;

[0010] The photoinitiator is an amine anthracene compound.

[0011] Preferably, the preparation method of the acrylic acid / polyurethane dual-modified epoxy resin comprises:

[0012] (1) After the multifunctional epoxy resin and the solvent are mixed, the polyurethane prepolymer is added and the catalyst 1 is added to react;

[0013] (2) Continue to add acrylic monomers and add catalyst 2 to react; after removing the solvent, the transparent viscous liquid obtained is the acrylic acid / polyurethane double-modified epoxy resin.

[0014] More preferably, the polyurethane prepolymer is an isocyanate-terminated prepolymer.

[0015] Preferably, the mass ratio of the multifunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomer is 100:25 to 100:12 to 25.

[0016] 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.

[0017] More preferably, in step (1), the reaction temperature is 80°C to 200°C, and the reaction time is 4h to 9h.

[0018] More preferably, in step (2), the reaction temperature is 80°C to 200°C, and the reaction time is 4h to 9h.

[0019] 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, tetraisobutyl titanate, p-toluenesulfonic acid, triethylamine, and triethylenediamine.

[0020] More preferably, the catalyst 2 is one or a combination of two or more of triphenylphosphine, triethylbenzylammonium bromide, tetrabutylammonium bromide, and 4-dimethylaminopyridine.

[0021] More preferably, the multifunctional epoxy resin is: bisphenol A glycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether methane, triglycidyl-p-aminophenol, triglycidyl triisocyanate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylene diamine, tetraglycidyl-1,3-bisaminomethylcyclohexylamine, or a combination of one or more of the above resins and their homologues and derivatives.

[0022] More preferably, the polyurethane prepolymer is one or a combination of two or more of polyether-modified polyisocyanate and polyester-modified polyisocyanate.

[0023] More preferably, the acrylic monomer is one or a combination of two or more of acrylic acid, methacrylic acid, acrylic anhydride, and acetic anhydride.

[0024] Preferably, 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 novolac epoxy resin.

[0025] Preferably, the epoxy curing agent is one or a combination of two or more of dicyandiamide, acetyl ketone, melamine, organic acid hydrazide, aromatic diazonium salt, and microencapsulated curing agent.

[0026] Preferably, the photoinitiator is one or a combination of two or more of 2,6-diaminoanthracene, 9-anilinoanthracene, anthracene-9-ylmethylamine, 9H-xanthene-9-amine, 9-aminoanthracene, (11R,12R)-9,10-dihydro-9,10-ethyleneanthracene-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.

[0027] Preferably, the raw materials of the one-component light-heat dual-curing epoxy adhesive include, by weight: 100 parts of acrylic acid / 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.

[0028] Preferably, the inorganic filler is spherical silicon powder.

[0029] Preferably, the dispersant is a non-solvent type high molecular weight wetting and dispersing agent.

[0030] Preferably, the raw materials further include a colorant, the amount of which is less than 10 wt % of the acrylic / polyurethane dual-modified epoxy resin.

[0031] More preferably, the colorant is one or more combinations of carbon black, iron oxide red, titanium dioxide, and phthalocyanine green.

[0032] Preferably, the preparation method of the one-component light-heat dual-curing epoxy adhesive comprises the following steps:

[0033] (a) Preparation of the main material: The low-viscosity epoxy resin and the acrylic acid / polyurethane dual-modified epoxy resin are uniformly mixed, and an inorganic filler and a dispersant are added, mixed, and ground. After mixing, the mixture is degassed, and the resulting main material is stored below 30°C.

[0034] (b) Preparation of adhesive: The remaining raw materials are added to the main ingredients, mixed and ground under vacuum conditions, and the mixture is filtered and discharged.

[0035] More preferably, the temperature when the low-viscosity epoxy resin and the acrylic acid / polyurethane dual-modified epoxy resin are mixed is 80° C. to 180° C.

[0036] More preferably, after adding the inorganic filler and dispersant, the temperature of mixing and grinding is 70°C to 110°C.

[0037] More preferably, during the preparation of the adhesive in step (b), the temperature is below 30°C.

[0038] More preferably, the degassing pressure condition is 0.06 MPa to 0.2 MPa.

[0039] More preferably, the vacuum condition is an air pressure below -0.08 MPa.

[0040] The present invention has the following beneficial effects:

[0041] (1) The present invention has good light-curing activity, high toughness and excellent high and low temperature resistance; compared with existing adhesives, other performances are basically unaffected;

[0042] (2) The photoinitiator used in the present invention can participate in the curing reaction in the system of the present invention, thereby avoiding the problem of degradation of the mechanical properties and bonding properties of the adhesive caused by the migration of initiator molecules;

[0043] (3) The curing process of the present invention is flexible and has small curing shrinkage, which meets the weather resistance requirements of semiconductor packaging. It is an epoxy adhesive for semiconductor packaging that is feasible in industrial applications.

[0044] In addition to the objects, features and advantages described above, the present invention has other objects, features and advantages. The present invention will be described in further detail below. DETAILED DESCRIPTION

[0045] In order to make the purpose, scheme and beneficial technology of the present invention clearer, the present invention is further described in detail below with reference to the embodiments. It should be noted that the embodiments described in this specification are only for explaining the present invention and are not intended to limit the present invention.

[0046] For simplicity, only some numerical ranges are explicitly disclosed herein. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, and similarly, any upper limit can be combined with any other upper limit to form an unspecified range. In addition, although not explicitly stated, each point or individual value between the endpoints of a range is included in the range. Thus, each point or individual value can serve as its own lower limit or upper limit and be combined with any other point or individual value, or with other lower limits or upper limits, to form an unspecified range.

[0047] In the description of this article, it should be noted that, unless otherwise specified, "above" and "below" are inclusive of the number itself, and the "multiple" in "one or more" means two or more, and the "multiple" in "one or more" means two or more.

[0048] The embodiment of the present invention provides a one-component light-heat dual-curing epoxy adhesive, which comprises, 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.

[0049] The acrylic acid / polyurethane double-modified epoxy resin is obtained by sequentially reacting a multifunctional epoxy resin with a polyurethane prepolymer and an acrylic monomer; wherein the mass ratio of the multifunctional epoxy resin, the polyurethane prepolymer and the acrylic monomer is 100:20-150:5-50;

[0050] The viscosity of the low-viscosity epoxy resin is 80 mPa·s to 2800 mPa·s; the epoxy value of the low-viscosity epoxy resin is 0.1 eq / 100 g to 0.9 eq / 100 g;

[0051] The particle size of the inorganic filler is 5nm~1000nm;

[0052] The photoinitiator is an amine anthracene compound.

[0053] In terms of dual photocuring, the embodiment of the present invention introduces an amine anthracene photoinitiator to achieve both photo- and thermal-induced curing effects: on the one hand, the anthracene structure can generate photoradicals under photoinitiation, thereby promoting photocuring of the double bonds in the acrylic / polyurethane dual-modified epoxy resin; on the other hand, the amine structure can function as an accelerator, participating in and promoting the reaction between the epoxy curing agent and the epoxy group under thermal curing conditions; the photoinitiator participates in the thermal curing reaction, effectively avoiding the phenomenon of molecular migration after curing caused by the traditional photoinitiator not participating in the thermal curing reaction, thereby effectively improving the reliability and adhesion of the epoxy adhesive.

[0054] In terms of main resin design, the embodiments of the present invention simultaneously introduce acrylic and polyurethane groups into the molecular structure of the epoxy resin through the method of acrylic / polyurethane dual modification; the introduction of acrylic groups can ensure the photocuring activity, and the polyurethane groups effectively improve the molecular flexibility of the cured products obtained by traditional epoxy thermal curing and acrylic photocuring, thereby enhancing the toughness and high and low temperature resistance of the epoxy adhesive.

[0055] In the design of the three-dimensional network structure of the epoxy resin, the present invention also selects low-viscosity epoxy resins such as bisphenol S, bisphenol A, bisphenol F epoxy resins, hydrogenated bisphenol A epoxy resins, and linear phenolic epoxy resins. During the photocuring process, the low-viscosity epoxy resin and the photocuring components form a mutually cross-linked interpenetrating network structure. The entire system has good compatibility, and the added filler is also uniformly dispersed in the matrix, thereby improving the toughness of the epoxy adhesive while basically leaving other performance aspects unaffected.

[0056] The single-component light-heat dual-curing epoxy adhesive provided by the embodiment of the present invention has the following advantages:

[0057] (1) The embodiments of the present invention have excellent light-curing activity, high toughness, and excellent high and low temperature resistance; compared with existing adhesives, other performance aspects are basically unaffected;

[0058] (2) The photoinitiator used in the embodiment of the present invention can participate in the curing reaction in the system of the present invention, thereby avoiding the problem of degradation of the mechanical properties and bonding properties of the adhesive caused by the migration of initiator molecules;

[0059] (3) The curing process available in the embodiment of the present invention is flexible and has small curing shrinkage, which meets the weather resistance requirements of semiconductor packaging. It is an epoxy adhesive for semiconductor packaging that is feasible in industrial applications.

[0060] In an embodiment of the present invention, the preparation method of the acrylic acid / polyurethane dual-modified epoxy resin comprises:

[0061] (1) After the multifunctional epoxy resin and the solvent are mixed, the polyurethane prepolymer is added and the catalyst 1 is added to react;

[0062] (2) Continue to add acrylic monomers and add catalyst 2 to react; after removing the solvent, the transparent viscous liquid obtained is the acrylic acid / polyurethane double-modified epoxy resin.

[0063] In some embodiments of the present invention, the polyurethane prepolymer is an isocyanate-terminated prepolymer.

[0064] In an embodiment of the present invention, the mass ratio of the multifunctional epoxy resin, the polyurethane prepolymer, and the acrylic monomer is 100:25-100:12-25.

[0065] The solvent can be removed by conventional means such as distillation under reduced pressure.

[0066] In some embodiments of the present invention, the added amount of each catalyst is 0.05% to 1% of the total mass of the reactants.

[0067] 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.

[0068] In some embodiments of the present invention, in step (1), the reaction temperature is 80°C to 200°C, and the reaction time is 4h to 9h.

[0069] In some embodiments of the present invention, in step (2), the reaction temperature is 80°C to 200°C, and the reaction time is 4h to 9h.

[0070] 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, tetraisobutyl titanate, p-toluenesulfonic acid, triethylamine, and triethylenediamine.

[0071] 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.

[0072] In some embodiments of the present invention, the multifunctional epoxy resin is: bisphenol A glycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether methane, triglycidyl-p-aminophenol, triglycidyl triisocyanate, tetraglycidyl diaminodiphenylmethane, tetraglycidyl xylene diamine, tetraglycidyl-1,3-bisaminomethylcyclohexylamine, or a combination of one or more of the above resins and their homologues and derivatives.

[0073] 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.

[0074] 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.

[0075] 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 novolac epoxy resin.

[0076] In an embodiment of the present invention, the epoxy curing agent is one or a combination of two or more of dicyandiamide, acetyl ketone, melamine, organic acid hydrazide, aromatic diazonium salt, and microencapsulated curing agent.

[0077] In an embodiment of the present invention, the photoinitiator is one or a combination of two or more of 2,6-diaminoanthracene, 9-anilinoanthracene, anthracene-9-ylmethylamine, 9H-xanthene-9-amine, 9-aminoanthracene, (11R,12R)-9,10-dihydro-9,10-ethyleneanthracene-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.

[0078] In an embodiment of the present invention, the raw materials of the one-component light-heat dual-curing epoxy adhesive include, by weight: 100 parts of acrylic acid / 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.

[0079] In an embodiment of the present invention, the inorganic filler is spherical silicon powder.

[0080] In an embodiment of the present invention, the dispersant is a non-solvent type high molecular weight wetting dispersant.

[0081] In an embodiment of the present invention, the raw materials further include a colorant, the amount of which is less than 10 wt % of the acrylic / polyurethane dual-modified epoxy resin.

[0082] In some embodiments of the present invention, the colorant is one or more combinations of carbon black, iron oxide red, titanium dioxide, and phthalocyanine green.

[0083] In an embodiment of the present invention, the preparation method of the one-component light-heat dual-curing epoxy adhesive comprises the following steps:

[0084] (a) Preparation of the main material: The low-viscosity epoxy resin and the acrylic acid / polyurethane dual-modified epoxy resin are uniformly mixed, and an inorganic filler and a dispersant are added, mixed, and ground. After mixing, the mixture is degassed, and the resulting main material is stored below 30°C.

[0085] (b) Preparation of adhesive: The remaining raw materials are added to the main ingredients, mixed and ground under vacuum conditions, and the mixture is filtered and discharged.

[0086] In order to avoid premature photoinitiation, the preparation of the adhesive in step (b) needs to be carried out under a non-UV light environment.

[0087] In some embodiments of the present invention, the temperature when the low-viscosity epoxy resin and the acrylic / polyurethane dual-modified epoxy resin are mixed is 80° C. to 180° C.

[0088] 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.

[0089] In some embodiments of the present invention, during the preparation of the adhesive in step (b), the temperature is below 30°C.

[0090] In some embodiments of the present invention, the degassing pressure condition is 0.06 MPa to 0.2 MPa.

[0091] In some embodiments of the present invention, the vacuum condition is an air pressure below -0.08 MPa.

[0092] Example

[0093] The following examples describe the present disclosure in more detail and are intended to be illustrative only, as various modifications and variations within the scope of the present disclosure will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight. Unless otherwise stated, all reagents used in the examples are available through conventional commercial sources or synthesized according to conventional methods and can be used directly without further processing. Unless otherwise stated, all instruments used in the examples are available through conventional commercial sources.

[0094] Example 1

[0095] The single-component light-heat dual-curing epoxy adhesive of this embodiment comprises, by weight, the following raw materials:

[0096] Acrylic acid / polyurethane double-modified epoxy resin (homemade) 100 parts;

[0097] 30 parts of low viscosity epoxy resin (bisphenol F epoxy resin);

[0098] Epoxy curing agent (melamine) 20 parts;

[0099] Inorganic filler (silica powder, spherical, 500nm) 180 parts;

[0100] Dispersant (BYK-110) 16 parts;

[0101] Colorant (carbon black) 4 parts;

[0102] Photoinitiator (2,6-diaminoanthracene) 1 part

[0103] The low-viscosity epoxy resin (bisphenol F epoxy resin) has an epoxy value of 0.42 eq / 100g and a viscosity of 1200 mPa·s.

[0104] The homemade acrylic / polyurethane dual-modified epoxy resin of this example is obtained by sequentially reacting a multifunctional epoxy resin (bisphenol A glycidyl ether, epoxy value 0.50 eq / 100g) with a polyurethane prepolymer (PTMEG-IPDI polyurethane prepolymer, molecular weight approximately 1000) and an acrylic monomer (methacrylic acid).

[0105] The main chemical reactions involved in the preparation process of the above acrylic acid / polyurethane dual-modified epoxy resin are as follows:

[0106] .

[0107] Acrylic acid / polyurethane double-modified epoxy resin, the specific preparation process is as follows:

[0108] (1) Add xylene and 100g of multifunctional epoxy resin to a three-necked flask and mix them evenly at 80°C; slowly add 80g of polyurethane prepolymer dropwise, mix evenly, then add catalyst (dibutyltin dilaurate) dropwise, and continue the reaction for 5h;

[0109] (2) Add 14 g of methacrylic acid, mix well, add catalyst (4-dimethylaminopyridine) dropwise, and continue the reaction for 5 h. After the reaction is completed, remove the solvent by distillation under reduced pressure and centrifuge to obtain a transparent viscous liquid, which is the acrylic acid / polyurethane double-modified epoxy resin.

[0110] The single-component light-heat dual-curing epoxy adhesive of this embodiment is obtained by mixing various raw materials. The specific preparation method is as follows:

[0111] (a) Preparation of the main material: Low-viscosity epoxy resin and acrylic / polyurethane dual-modified epoxy resin were added to a planetary mixer and mixed at 90°C. Inorganic fillers and dispersants were then added. The material temperature was maintained at 90°C and stirred at high speed for 60 minutes. The mixture was then ground twice on a three-roll mill to ensure a more uniform dispersion of the filler. Degassing was performed at a pressure of 0.1 MPa, and the material was then cooled to below 20°C for later use.

[0112] (b) Preparation of Adhesive: The remaining raw materials were added to the main material and stirred under vacuum (less than -0.08 MPa) for 60 min. The material temperature was controlled below 20°C and kept in a non-UV light environment throughout the process. The material was ground and finally filtered using a press for packaging.

[0113] Example 2

[0114] The single-component light-heat dual-curing epoxy adhesive of this embodiment comprises, by weight, the following raw materials:

[0115] Acrylic acid / polyurethane double-modified epoxy resin (homemade) 100 parts;

[0116] Low viscosity epoxy resin (bisphenol A epoxy resin) 18 parts;

[0117] Epoxy curing agent (dicyandiamide) 16 parts;

[0118] Inorganic filler (silica powder, spherical, 500nm) 200 parts;

[0119] Dispersant (BYK-110) 8 parts;

[0120] Colorant (iron red) 2 parts;

[0121] 1.3 parts of photoinitiator (9,10-bis[N-(m-tolyl)phenylamino]anthracene)

[0122] The low-viscosity epoxy resin (bisphenol A epoxy resin) has an epoxy value of 0.51 eq / 100g and a viscosity of 300 mPa·s.

[0123] The homemade acrylic acid / polyurethane dual-modified epoxy resin of this embodiment is obtained by sequentially reacting a multifunctional epoxy resin (tetraglycidyl diaminodiphenylmethane) with a polyurethane prepolymer (polyether polyol-MDI hydroxyl-containing polyurethane prepolymer (molecular weight of about 3000)) and an acrylic monomer (acrylic acid). The specific preparation process is as follows:

[0124] (1) Add solvent (toluene) and 82g of tetraglycidyldiaminodiphenylmethane to a three-necked flask and mix them evenly at 100°C; slowly add 40g of polyether polyol-MDI hydroxyl polyurethane prepolymer (molecular weight 3000) dropwise, mix evenly, add 0.5g of catalyst (tetraisobutyl titanate), and continue the reaction for 6h;

[0125] (2) Add 18 g of acrylic acid, mix well, add catalyst (tetrabutylammonium bromide) dropwise, and continue the reaction for 4 h. After the reaction is completed, remove the solvent by vacuum distillation and centrifuge to obtain a transparent viscous liquid, which is the acrylic acid / polyurethane double-modified epoxy resin.

[0126] The single-component light-heat dual-curing epoxy adhesive of this embodiment is obtained by mixing various raw materials. The specific preparation method is as follows:

[0127] (a) Preparation of the main material: Low-viscosity epoxy resin and acrylic / polyurethane dual-modified epoxy resin were added to a planetary mixer and mixed at 80°C. Inorganic fillers and dispersants were then added. The material temperature was maintained at 80°C and stirred at high speed for 60 minutes. The mixture was then ground twice on a three-roll mill to ensure a more uniform dispersion of the filler. Degassing was performed at a pressure of 0.1 MPa, and the material was then cooled to below 20°C for later use.

[0128] (b) Preparation of Adhesive: The remaining raw materials were added to the main material and stirred under vacuum (less than -0.08 MPa) for 45 min. The material temperature was controlled below 20°C and kept in a non-UV light environment throughout the process. The material was ground and finally filtered using a press for packaging.

[0129] Example 3

[0130] The single-component light-heat dual-curing epoxy adhesive of this embodiment comprises, by weight, the following raw materials:

[0131] Acrylic acid / polyurethane double-modified epoxy resin (homemade) 100 parts;

[0132] Low viscosity epoxy resin (bisphenol F epoxy resin) 20 parts;

[0133] Epoxy curing agent (melamine) 15 parts;

[0134] Inorganic filler (silica powder, spherical, 800nm) 200 parts;

[0135] Dispersant (BYK-110) 8 parts;

[0136] Colorant (carbon black) 4 parts;

[0137] Photoinitiator (2,6-diaminoanthracene) 1 part

[0138] The low-viscosity epoxy resin (bisphenol F epoxy resin) has an epoxy value of 0.42 eq / 100g and a viscosity of 1200 mPa·s.

[0139] The homemade acrylic acid / polyurethane dual-modified epoxy resin of this embodiment is obtained by sequentially reacting a multifunctional epoxy resin (triphenyl glycidyl ether methane) with a PTMEG-TDI hydroxyl-containing polyurethane prepolymer (molecular weight of approximately 2000) and an acrylic monomer (methacrylic acid). The specific preparation process is as follows:

[0140] (1) Add solvent (toluene) and 55g of multifunctional epoxy resin to a three-necked flask and mix them evenly at 80°C; slowly add 15g of polyurethane prepolymer dropwise, mix evenly, then add 0.1g of catalyst (stannous octoate) dropwise, and continue the reaction for 4h;

[0141] (2) Add 8 g of acrylic monomer, mix well, add 0.05 g of catalyst (triethylbenzylammonium bromide) dropwise, and continue the reaction for 5 h. After the reaction is completed, remove the solvent by vacuum distillation and centrifuge to obtain a transparent viscous liquid, which is the acrylic / polyurethane double-modified epoxy resin.

[0142] The single-component light-heat dual-curing epoxy adhesive of this embodiment is obtained by mixing various raw materials. The specific preparation method is as follows:

[0143] (a) Preparation of the main material: Low-viscosity epoxy resin and acrylic / polyurethane dual-modified epoxy resin were added to a planetary mixer and mixed at 85°C. Inorganic fillers and dispersants were then added. The material temperature was controlled at 90°C and stirred at high speed for 60 minutes. The mixture was then ground twice on a three-roll mill to ensure a more uniform dispersion of the filler. Degassing was performed at a pressure of 0.2 MPa, and the material was then cooled to below 20°C for later use.

[0144] (b) Preparation of Adhesive: The remaining raw materials were added to the main material and stirred under vacuum (less than -0.08 MPa) for 60 min. The material temperature was controlled below 20°C and kept in a non-UV light environment throughout the process. The material was ground and finally filtered using a press for packaging.

[0145] Comparative Example 1

[0146] The raw materials and preparation method of the adhesive in this comparative example are basically the same as those in Example 1, except that, instead of preparing an acrylic acid / polyurethane double-modified epoxy resin, the raw materials of the acrylic acid / polyurethane double-modified epoxy resin - bisphenol A glycidyl ether, PTMEG-IPDI polyurethane prepolymer, and methacrylic acid - are directly used as raw materials for the adhesive in the original proportion.

[0147] Comparative Example 2

[0148] 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 acid / polyurethane double-modified epoxy resin is not used, but the bisphenol A glycidyl ether in Example 1 is used instead.

[0149] Comparative Example 3

[0150] 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 by the Irgacure 2959 photoinitiator commonly used in the art.

[0151] Comparative Example 4

[0152] The adhesive raw materials and preparation method of this comparative example are basically the same as those of Example 1, except that the low-viscosity epoxy resin (bisphenol F epoxy resin) is replaced by trimethylolpropane triacrylate (TMPTA), a reactive diluent commonly used in light-curing adhesives.

[0153] Detection and analysis

[0154] The adhesives of the examples and comparative examples, as well as a commercially available single-component photothermal dual-curing epoxy adhesive (SUNSTAR 1122), were tested for various performance indicators. Curing conditions were: single-stage curing (light): 365nm LED light, 1500mW / cm 2 , 10s; secondary curing (heat): 80℃ / 60min, 100℃ / 30min; the test results of the examples and commercially available products are shown in Table 1, the test results of the comparative examples are shown in Table 2, and the test standards adopted are also shown in Tables 1 and 2.

[0155] As can be seen from Table 1, the adhesives of Examples 1 to 3 of the present invention have a certain improvement in flexural strength and a significant improvement in shear strength compared to commercially available products, especially the shear strength after thermal shock resistance and the shear strength after the double 85 test, which are basically more than twice that of commercially available products.

[0156] Table 1 Performance test results of adhesives in various examples and commercially available products

[0157]

[0158] Combining Tables 1 and 2, it can be seen that among the comparative examples, Comparative Example 3, in which the photoinitiator is replaced relative to Example 1, exhibits superior shear strength, flexural strength, shear strength after thermal shock resistance, and shear strength after the double 85 test to commercially available products, but still significantly lower than Example 1. The synergistic effect between the components of the composition of the present invention is the key to the significant improvement in shear strength of the present invention. In Comparative Example 4, the low-viscosity epoxy resin of the present invention is replaced with a reactive diluent commonly used in photocurable adhesives. This reactive diluent cannot form an interpenetrating network structure with the photocurable component, resulting in lower performance compared to the examples of the present invention.

[0159] Table 2 Performance test results of adhesives in various comparative examples

[0160]

[0161] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A one-component light-heat dual-curing epoxy adhesive, characterized in that: The raw materials include, by weight: 100 parts of acrylic acid / 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 preparation method of the acrylic acid / polyurethane double-modified epoxy resin comprises: (1) After the multifunctional epoxy resin and the solvent are mixed, the polyurethane prepolymer is added and the catalyst 1 is added to react; (2) continuing to add acrylic monomers and adding catalyst 2 to react; after removing the solvent, the resulting transparent viscous liquid is the acrylic acid / polyurethane dual-modified epoxy resin; The mass ratio of the multifunctional epoxy resin, the polyurethane prepolymer and the acrylic monomer is 100:20-150:5-50; In step (1), the reaction temperature is 80°C to 200°C, and the reaction time is 4h to 9h; In step (2), the reaction temperature is 80°C to 200°C, and the reaction time is 4h to 9h; The multifunctional epoxy resin is bisphenol A glycidyl ether with an epoxy value of 0.50eq / 100g; The polyurethane prepolymer is an isocyanate-terminated prepolymer; The viscosity of the low-viscosity epoxy resin is 80 mPa·s to 2800 mPa·s; the epoxy value of the low-viscosity epoxy resin is 0.1 eq / 100 g to 0.9 eq / 100 g; The particle size of the inorganic filler is 5nm to 1000nm; The photoinitiator is an amine anthracene compound.

2. The one-component light-heat dual-curing epoxy adhesive according to claim 1, characterized in that: The mass ratio of the multifunctional epoxy resin, the polyurethane prepolymer and the acrylic monomer is 100:25 to 100:12 to 25.

3. The one-component light-heat dual-curing epoxy adhesive according to claim 1, 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; 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, tetraisobutyl 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 light-heat dual-curing epoxy adhesive according to claim 1, characterized in that: 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 anhydride.

5. The one-component light-heat dual-curing epoxy adhesive 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 novolac epoxy resin; The epoxy curing agent is one or a combination of two or more of dicyandiamide, acetyl ketone, 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, anthracene-9-ylmethylamine, 9H-xanthene-9-amine, 9-aminoanthracene, (11R,12R)-9,10-dihydro-9,10-ethyleneanthracene-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 light-heat dual-curing epoxy adhesive according to claim 1, characterized in that: The raw materials include, by weight: 100 parts of acrylic acid / 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 silicon powder; The dispersant is a non-solvent type high molecular weight wetting dispersant.

7. The one-component light-heat dual-curing epoxy adhesive according to claim 1, characterized in that: The raw materials also include a colorant, the amount of which is less than 10wt% of the acrylic acid / polyurethane double-modified epoxy resin.

8. The one-component light-heat dual-curing epoxy adhesive according to claim 7, characterized in that: The colorant is one or more combinations of carbon black, iron oxide red, titanium dioxide, and phthalocyanine green.

9. The one-component light-heat dual-curing epoxy adhesive according to any one of claims 1, 6, 7, and 8, characterized in that: The preparation method comprises the following steps: (a) Preparation of the main material: The low-viscosity epoxy resin and the acrylic acid / polyurethane dual-modified epoxy resin are uniformly mixed, and an inorganic filler and a dispersant are added, mixed, and ground. After mixing, degassing is performed, and the resulting main material is stored below 30° C.; (b) Preparation of adhesive: The remaining raw materials are added to the main ingredients, mixed and ground under vacuum conditions, and the mixture is filtered and discharged.

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

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