Adhesive compositions and their cured products

Abstract

The object of this invention is to provide an adhesive composition with excellent adhesion and crack resistance. This invention relates to a conductive adhesive composition comprising (a) a (meth)acrylate monomer, (b) a tackifier, (c) bismaleimide, and (d) a free radical initiator, wherein the homopolymer of the (meth)acrylate monomer (a) has a glass transition temperature (Tg) of 50°C or lower, and the tackifier (b) has a Hazen unit color number of 300 or lower.

Description

Technical Field

[0001] This invention relates to an adhesive composition and its cured product. Background Technology

[0002] In the production of camera and sensor module integrators, adhesives are used to bond electronic components to a substrate. First, these adhesives need to maintain good adhesion after curing. In particular, they need to maintain good adhesion even during reliability testing in high-temperature and high-humidity environments.

[0003] Secondly, these adhesives also need to have excellent crack resistance. Epoxy resin-containing adhesives are used in the aforementioned applications. While they show good results in reliability tests, they are prone to cracking after curing due to excessive hardness. Furthermore, epoxy resin-containing adhesives have the following problems: due to the soft blocks of epoxy resin, they often cure insufficiently at low temperatures, and due to their excessively high viscosity, they are difficult to use.

[0004] Therefore, adhesives containing acrylic resins are proposed, in which the cured products tend to have low elasticity (PTL 1 and PTL 2).

[0005] Reference List

[0006] Patent documents

[0007] PTL 1:JP2016-117860A

[0008] PTL 2:JP2018-159042A Summary of the Invention

[0009] Technical issues

[0010] The inventors have discovered that adhesives containing acrylic resin have the following problems: when acrylic resin is the only resin component, the adhesion is often insufficient and delamination is likely to occur after curing.

[0011] The purpose of this invention is to provide an adhesive composition with excellent adhesion and crack resistance.

[0012] Solution

[0013] The inventors conducted extensive research to address the aforementioned problems and envisioned using acrylic resins and tackifiers in combination in adhesive compositions. However, tackifiers typically inhibit the polymerization of acrylic resins, making it difficult to solve the problems simply by combining them. The inventors conducted further research and discovered that the problems could be solved by selecting tackifiers that are unlikely to inhibit polymerization and combining these tackifiers with the acrylic resin. This invention was made based on further research following the above findings and includes the following aspects.

[0014] Project 1

[0015] An adhesive composition comprising:

[0016] (a) (meth)acrylate monomer;

[0017] (b) Tackifier;

[0018] (c) bismaleimide; and

[0019] (d) Free radical initiators

[0020] The homopolymer of the (meth)acrylate monomer (a) has a glass transition temperature (Tg) of 50°C or lower, and

[0021] The tackifier (b) has a Hazen unit color number of 300 or less.

[0022] Project 2

[0023] According to the adhesive composition of Project 1, the tackifier (b) has an acid value of 350 (KOH mg / g) or less.

[0024] Project 3

[0025] According to the adhesive composition of item 1 or 2, wherein the tackifier (b) has a softening point of 150°C or lower.

[0026] Project 4

[0027] The adhesive composition according to any one of items 1 to 3, wherein the bismaleimide (c) is represented by formula (I):

[0028]

[0029] Where n represents an integer from 1 to 40, and R represents C1-C2. 12 Linear or at least partially cyclic divalent hydrocarbon group.

[0030] Project 5

[0031] The adhesive composition according to any one of items 1 to 4 further comprises:

[0032] (e) Conductive filler.

[0033] Project 6

[0034] The adhesive composition according to any one of items 1 to 5 is used for assembling camera modules or sensors.

[0035] Project 7

[0036] The adhesive composition according to any one of items 1 to 5 is used for assembling camera modules or sensors.

[0037] Project 8

[0038] A cured product, which can be obtained by curing an adhesive composition according to any one of items 1 to 5.

[0039] Project 9

[0040] A method for assembling a camera module or sensor, the method comprising bonding electronic components to a substrate using an adhesive composition according to any one of items 1 to 5.

[0041] Advantages of the invention

[0042] According to the present invention, the adhesion and crack resistance of the adhesive composition can be improved. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the pull-out tensile test method in the embodiment. Detailed Implementation

[0044] In this specification, the weight-average molecular weight (M) w The conversion value of polystyrene is determined by gel permeation chromatography (GPC) using a solvent such as tetrahydrofuran as the eluent.

[0045] In this specification, the term "(meth)acrylic acid" is used as a term that includes both acrylic acid and methacrylic acid.

[0046] (a) (Meth)acrylate monomer

[0047] (Meth)acrylate monomer (a) is well known to those skilled in the art and may be a monofunctional (meth)acrylate or a polyfunctional (meth)acrylate.

[0048] Homopolymers of (meth)acrylate monomer (a) have a glass transition temperature of 50°C or lower (T0). g Therefore, the adhesive composition of the present invention does not have excessive elasticity after curing, and crack formation is easily suppressed. In this regard, the homopolymer of (meth)acrylate monomer (a) preferably has a glass transition temperature (T) of 30°C or lower. g ).

[0049] The glass transition temperature (Tg) is measured using the following method:

[0050] (Meth)acrylate monomers and azobis(isobutyronitrile) (AIBN) were dissolved in methyl ethyl ketone (MEK), and the mixture was heated to 50 °C to polymerize the monomers. Subsequently, hexane was used for precipitation, and the resulting polymer was collected. The glass transition temperature of the polymer was measured by differential scanning calorimetry (DSC).

[0051] Specific examples of monofunctional methacrylates include n-propyl methacrylate, glycidyl methacrylate, 2-hydroxyethyl methacrylate, 2-methacryloyloxyethyltrimethoxysilane, 2-methacryloyloxyethyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, 3-methacryloyloxymethyldiethoxysilane, 4-methacryloyloxybutyltrimethoxysilane, 4-methacryloyloxybutyltriethoxysilane, dicyclopentenoxyethyl methacrylate (e.g., product name "FA-512M" manufactured by Hitachi Chemical Co., Ltd.), pentamethylpiperidinyl methacrylate (e.g., product name "FA-711MM" manufactured by Hitachi Chemical Co., Ltd.), and tetramethylpiperidinyl methacrylate (e.g., product name "FA-711MM" manufactured by Hitachi Chemical Co., Ltd.). Products manufactured by Hitachi Chemical Co., Ltd. under the name "FA-712HM"), methoxy polyethylene glycol methacrylate (e.g., product name "FA-400M" manufactured by Hitachi Chemical Co., Ltd.), 2-hydroxy-3-acryloyloxypropyl methacrylate (e.g., product name "Light Ester G-201P" manufactured by Kyoeisha Chemical Co., Ltd.), phenoxy polyethylene glycol methacrylate (e.g., product name "PHE-1G" manufactured by Shin-Nakamura Chemical Co., Ltd.), stearyl methacrylate (e.g., product name "S" manufactured by Shin-Nakamura Chemical Co., Ltd.), 2-methacryloyloxyethyl succinate (e.g., product name "SA" manufactured by Shin-Nakamura Chemical Co., Ltd.), methyl 3,4-epoxycyclohexyl methacrylate (e.g., product name "Cyclomer M100" manufactured by Daicel Corporation), etc.

[0052] Specific examples of bifunctional methacrylates include dipropylene glycol diacrylate (e.g., product name "APG-100" manufactured by Shin-Nakamura Chemical Co., Ltd.), neopentyl glycol dimethacrylate (e.g., product name "FA-125M" manufactured by Hitachi Chemical Co., Ltd.), polyethylene glycol #200 dimethacrylate (e.g., product name "FA-220M" manufactured by Hitachi Chemical Co., Ltd.), ethylene oxide-modified bisphenol A dimethacrylate (e.g., product name "FA-321M" manufactured by Hitachi Chemical Co., Ltd.), ethylene oxide-modified polypropylene glycol #700 dimethacrylate (e.g., product name "FA-023M" manufactured by Hitachi Chemical Co., Ltd.), and ethylene glycol dimethacrylate (e.g., product name "FA-023M" manufactured by Shin-Nakamura Chemical Co., Ltd.). Products manufactured by Shin-Nakamura Chemical Co., Ltd. under the product name "1G"), diethylene glycol dimethacrylate (e.g., product name "2G" manufactured by Shin-Nakamura Chemical Co., Ltd.), triethylene glycol dimethacrylate (e.g., product name "3G" manufactured by Shin-Nakamura Chemical Co., Ltd.), polyethylene glycol dimethacrylate (e.g., manufactured by Shin-Nakamura Chemical Co., Ltd.), 2,2-bis[4-(methacryloyloxyethoxy)phenyl]propane (e.g., product name "BPE-80N" manufactured by Shin-Nakamura Chemical Co., Ltd.), ethoxylated bisphenol A dimethacrylate (e.g., manufactured by Shin-Nakamura Chemical Co., Ltd.), 1,10-decanediol dimethacrylate (e.g., manufactured by Shin-Nakamura Chemical Co., Ltd.). The following are product names produced by Shin-Nakamura Chemical Co., Ltd.: 1,6-hexanediol dimethacrylate (e.g., product name "HD-N" produced by Shin-Nakamura Chemical Co., Ltd.), 1,9-nonanediol dimethacrylate (e.g., product name "NOD-N" produced by Shin-Nakamura Chemical Co., Ltd.), neopentyl glycol dimethacrylate (e.g., product name "NPG" produced by Shin-Nakamura Chemical Co., Ltd.), and ethoxylated polypropylene glycol dimethacrylate (e.g., by Shin-Nakamura Chemical Co., Ltd.).This includes products such as glycerol dimethacrylate (e.g., product name "701" manufactured by Shin-Nakamura Chemical Co., Ltd.), and polypropylene glycol dimethacrylate (e.g., manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0053] The adhesive composition of the present invention may contain only one type of (meth)acrylate monomer (a), or may contain two or more types of (meth)acrylate monomer (a).

[0054] With regard to excellent curability and crosslinking density control, the adhesive composition of the present invention preferably contains 7 wt% or more, more preferably 10 wt% or more of (meth)acrylate monomer (a) based on the whole composition. The adhesive composition of the present invention preferably contains 30% or less, more preferably 20% or less of tackifier based on the whole composition.

[0055] In addition to the (meth)acrylate monomer (a), the adhesive composition of the present invention may also contain the glass transition temperature (Tg) of its homopolymer. g (Meth)acrylate monomers at temperatures above 50°C, as long as the effects of the present invention are not compromised.

[0056] (b) Tackifier

[0057] The tackifier has a Hazen unit color number of 300 or less. Therefore, in the adhesive composition of the present invention, the polymerization of (meth)acrylate monomer (a) is unlikely to be inhibited by the tackifier.

[0058] In this invention, the polymerization of (meth)acrylate monomer (a) is less likely to be inhibited by the tackifier because a tackifier with a Hazen unit color number of 300 or less is used. This is believed to be because when a tackifier with a Hazen unit color number greater than 300 is used, the double bonds derived from the structure act as free radical traps, inhibiting the polymerization of the acrylic resin. In tackifiers with a Hazen unit color number of 300 or less, the double bonds of the tackifier are hydrogenated, making it difficult to inhibit polymerization.

[0059] In this invention, the Hazen unit color number is measured as follows: 55 grams of sample are dissolved in 55 grams of toluene, and 100 ml of this solution is accurately placed in a Nessler tube. The color is then compared to the color of a Hazen standard color test tube. At this point, white paper is placed below the test tube, the tube is slightly raised from the bottom, and the color is compared to the standard color above. The Hazen index of the standard color closest to the hue is read, and the value obtained by doubling the index is reported. When the sample color is in the middle of the standard colors, the middle value is doubled.

[0060] The acid value of the tackifier is preferably 350 (KOH mg / g) or lower. Therefore, the adhesive composition of the present invention has excellent viscosity stability.

[0061] In this invention, the acid value is measured as follows: Approximately 3g of sample is accurately weighed into a 100ml conical flask and dissolved in an ethanol / ether mixture (1:2). The resulting product is titrated with 0.1mol / L potassium hydroxide (ethanol solution) using phenolphthalein as an indicator. The time it takes for the pale red color to persist for 30 seconds is defined as the neutralization endpoint, and the acid value is calculated according to the following formula.

[0062] Acid value = (axfx 5.61) / sample (g)

[0063] a: Volume (ml) of 0.1 mol / L potassium hydroxide (ethanol solution)

[0064] f: Titer of 0.1 mol / L potassium hydroxide (ethanol solution)

[0065] The softening point of the tackifier is preferably 150°C or lower. Therefore, the adhesive composition of the present invention has improved elongation and flexibility.

[0066] In this invention, the softening point is measured using the ring and ball method as follows: The sample is packaged in a ring, and any protrusions from the flat surface, including the upper end of the ring, are scraped off with a heated spatula. This is placed in the appropriate position on a support, with a rigid ball placed at the center. The support is placed in a glycerol bath and heated at a rate of 5.0 ± 0.5 °C / min. The softening point is defined as the moisture content at which the sample softens and comes into contact with the substrate.

[0067] Examples of available tackifiers include various resins. These resins are preferably hydrogenated resins. Preferred resins include rosin resins, rosin ester resins, terpene resins, terpene phenolic resins, etc. Examples of hydrogenated resins include hydrogenated terpene phenolic resin (product name: YS Polystar UH, manufactured by Yasuhara Chemical Co., Ltd.), hydrogenated petroleum resin (product name: Alcon P-100, manufactured by Arakawa Chemical Industries, Ltd.), colorless rosin derivative (product name: KE-359, manufactured by Arakawa Chemical Industries, Ltd.), colorless rosin derivative (product name: KR-140, manufactured by Arakawa Chemical Industries, Ltd.), colorless rosin derivative (product name: KE-100, manufactured by Arakawa Chemical Industries, Ltd.), etc.

[0068] The adhesive composition of the present invention may contain only one type of tackifier, or may contain two or more types of tackifiers.

[0069] For achieving excellent pull-out tensile strength, the adhesive composition of the present invention preferably contains 0.5 wt% or more, more preferably 1 wt% or more of tackifier, based on the entire composition. For achieving a viscosity range suitable for good processability, the adhesive composition of the present invention preferably contains 15 wt% or less, more preferably 10 wt% or less of tackifier, based on the entire composition.

[0070] In the adhesive composition of the present invention, the weight ratio of (meth)acrylate monomer (a) to tackifier is preferably 90:10 to 70:30, more preferably 85:15 to 75:25, in order to maintain processability while obtaining excellent pull-out strength.

[0071] (c) Bismaleimide

[0072] The adhesive composition of the present invention contains bismaleimide, with the aim of imparting excellent metal adhesion and the ability to maintain adhesion in reliability tests to the composition and its cured product.

[0073] In terms of maintaining excellent strength in reliability tests, bismaleimide is preferably represented by formula (I).

[0074]

[0075] Where n represents an integer from 1 to 40, and R represents C1-C2. 12 Linear or at least partially cyclic divalent hydrocarbon group.

[0076] In formula (I), n is preferably 1 to 36 in terms of maintaining excellent strength in reliability tests. In formula (I), the lower limit of n is preferably 6, more preferably 12, even more preferably 24, and even more preferably 30.

[0077] In formula (I), R preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms. R can be a divalent hydrocarbon group that partially contains an aromatic ring. R is preferably an alkylene group that may partially contain an aromatic ring.

[0078] The adhesive composition of the present invention may contain only one type of bismaleimide, or may contain two or more types of bismaleimide.

[0079] Regarding excellent adhesion, the adhesive composition of the present invention preferably contains 3 wt% or more, more preferably 5 wt% or more of bismaleimide, based on the entire composition. Regarding maintaining good processability, the adhesive composition of the present invention preferably contains 15 wt% or less, more preferably 12 wt% or less of bismaleimide, based on the entire composition.

[0080] (d) Polymerization initiator

[0081] There are no particular restrictions on the polymerization initiator; commonly used polymerization initiators in the technical field can be used.

[0082] For excellent low-temperature curing, the polymerization initiator preferably has a half-life temperature of 1 hour at 100°C or lower, more preferably 85°C or lower.

[0083] Specific examples of polymerization initiators (d) include Perbutyl O (tert-butyl peroxy-2-ethylhexanoate), Perhexyl O (tert-hexyl peroxy-2-ethylhexanoate), Perocta O (1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate), Perbutyl ND (tert-butyl peroxyneodecanate), and Peroyl TCP (bis(4-tert-butylcyclohexyl)peroxydicarbonate) (all manufactured by NOF Corporation).

[0084] Polymerization initiators (d) can be used alone or in combination of two or more.

[0085] Regarding excellent curability, the adhesive composition of the present invention preferably contains 0.5 wt% or more, more preferably 1 wt% or more of a polymerization initiator, based on the entire composition. Regarding the stability of adhesion, the adhesive composition of the present invention preferably contains 5 wt% or less, more preferably 2 wt% or less of a polymerization initiator, based on the entire composition.

[0086] (e) Conductive filler

[0087] The adhesive composition of the present invention may also contain conductive fillers. There are no particular limitations on the conductive fillers; commonly used conductive fillers in the technical field can be used.

[0088] Examples of conductive fillers include conductive metals such as silver, copper, gold, aluminum, palladium, platinum, bismuth, and tin.

[0089] Alloys can also be used as conductive fillers. Examples of alloys include those composed of two or more of the aforementioned metals. Specific examples include bismuth-tin alloys, etc.

[0090] Conductive metal oxides can also be used as conductive fillers. Examples of conductive metal oxides include oxides of the aforementioned conductive metals. Specific examples include indium tin oxide, etc.

[0091] Structures further coated with a conductive metal can also be used as conductive fillers. Examples of such structures include those obtained by coating one of the aforementioned conductive metals with another conductive metal. Specific examples include silver-plated copper, silver-plated aluminum, etc.

[0092] Structures further coated with conductive metals can also be used as conductive fillers. Examples of such structures include those obtained by coating other substances with the aforementioned conductive metals. Specific examples include metal-coated glass spheres, etc.

[0093] In terms of processability and low viscosity, the average particle size of the conductive filler is preferably 0.1 to 50 μm, more preferably 2 to 20 μm. In this specification, the average particle size of the conductive filler refers to the volume-based median particle size measured by laser diffraction.

[0094] For lower resistance, the conductive filler is preferably in sheet form.

[0095] Examples of conductive fillers include silver powder (product name: FA6-18) produced by DOWA Electronics Materials Co., Ltd., silver powder (product name: K-0082P) produced by Metalor Technologies USA, and silver powder (product name: SL02) produced by Mitsui Mining & Smelting Co., Ltd.

[0096] The adhesive composition of the present invention may contain only one type of conductive filler, or may contain two or more types of conductive fillers.

[0097] In terms of exhibiting excellent conductivity and processability, the adhesive composition of the present invention, based on the whole composition, preferably contains 50 wt% or more, more preferably 60 wt% or more of conductive filler. In terms of suppressing viscosity increase, the adhesive composition of the present invention, based on the whole composition, preferably contains 80 wt% or less, more preferably 75 wt% or less of conductive filler.

[0098] Other components

[0099] The adhesive composition of the present invention may further comprise other components. Examples of other components as adhesive additives include various coupling agents, such as silanes and titanates, and rheology modifiers, such as fumed silica.

[0100] Physical properties

[0101] The adhesive composition of the present invention preferably has a pull strength of 4 MPa or greater, more preferably 5 MPa or greater, after curing. In the present invention, the pull strength is measured as follows: [Example...] Figure 1 As shown, a paste is applied to a nickel plate of a predetermined size, and then another nickel plate is placed on top of the paste. To maintain a constant film thickness, a 0.1 mm shim is inserted between them. The amount of paste applied is adjusted so that the diameter after pressure bonding is 3 mm. After curing in an oven at 80°C for 1 hour, the nickel plate is pulled vertically at a speed of 10 mm / min at room temperature. The stress at this point is defined as the pull-out tension.

[0102] The adhesive composition of the present invention preferably has a storage modulus of 1000 MPa or less, more preferably 500 MPa or less (25°C) after curing. At this temperature, even due to heat and / or physical shock, mismatch in the coefficients of thermal expansion between the adherend surface and the adhesive is unlikely. Therefore, the adhesive composition of the present invention exhibits excellent crack resistance.

[0103] In the adhesive composition of the present invention, the rate of reduction in pull-out tensile strength after curing in a reliability test (85°C / 85RH-250h) is preferably 30% or less, more preferably 20% or less.

[0104] use

[0105] The adhesive composition of the present invention is preferably used for assembling camera modules and sensors. There are no particular limitations on the camera modules and sensors described above; examples include small camera modules and small sensors for smartphones and the like.

[0106] Example

[0107] The adhesive compositions of Comparative Examples 1 to 4 and Examples 1 and 2 were all prepared by mixing the components in the proportions shown in Table 1. Specifically, the (meth)acrylate monomers containing the tackifier, polymerization initiator, conductive filler, other additives, etc., were thoroughly dispersed using a planetary mixer, and then vacuum defoaming was performed to obtain the adhesive composition.

[0108] The physical properties were evaluated as follows. The evaluation results are shown in Table 1.

[0109] Energy storage modulus test

[0110] The mixed adhesive paste was cured to a thickness of 0.3 mm at 80°C for 60 minutes to form a sheet. The sheet was then cut into 10 mm wide strips, and dynamic viscoelasticity (DMA) measurements were performed in tensile mode, with the storage modulus E' measured from -40°C to 250°C.

[0111] Adhesion test

[0112] Adhesion test such as Figure 1 The procedure is as shown. Details are as follows: Apply the paste to a 10cm x 5cm nickel plate, and then place another 5mm x 5mm nickel plate on top of the paste. To maintain a constant film thickness, insert a 0.1mm shim between them. Adjust the paste application amount so that the diameter after pressure bonding is 3mm. After curing in an oven at 80°C for 1 hour, use a tensile compression testing machine (manufactured by IMADA-SS Corporation) to pull the nickel plate vertically at room temperature at a speed of 10mm / min. The stress at this point is defined as the pull-out tensile force.

[0113] The reliability test conditions after curing were 85℃ / 85% RH and 250 hours.

[0114] Table 1

[0115]

[0116]

[0117] Table 2

[0118]

[0119] The following components were used.

[0120] Table 3

[0121]

[0122]

[0123] The BMI used is represented by the following formula (I).

[0124]

[0125] Where n is shown in Table 2, and R represents -C4H8-.

[0126] Examples 1 to 3

[0127] The evaluation results are shown in Table 1. The adhesive compositions of Examples 1 to 3 exhibited excellent storage modulus and pull-out tensile strength after curing. Furthermore, since the adhesive compositions of Examples 1 and 2 used a BMI of n=36 in Formula (I), the pull-out tensile strength reduction rate after reliability testing was particularly low.

[0128] Comparative Example 1

[0129] Since the adhesive composition of Comparative Example 1 does not contain a tackifier, the pull-out force after curing is low.

[0130] Comparative Example 2

[0131] Since the adhesive composition of Comparative Example 2 contains homopolymers with a Tg of 97°C and homopolymers with a Tg of 186°C as (meth)acrylate monomers, the storage modulus after curing is too high.

[0132] Comparative Example 3

[0133] Because the adhesive composition of Comparative Example 3 uses a tackifier with Gardner color 10, the pull-out force after curing is low.

Claims

1. An adhesive composition comprising: (a) (meth)acrylate monomer; (b) Tackifier; (c) Bismaleimide; (d) Free radical initiators; and (e) Based on 50-80% by weight of conductive filler in the whole composition, The homopolymer of the (meth)acrylate monomer (a) has a glass transition temperature (Tg) of 2°C to 30°C, and The tackifier (b) has a Hazen unit color number of 300 or less, and is selected from hydrogenated rosin resin, hydrogenated rosin ester resin, hydrogenated terpene resin, and hydrogenated terpene phenolic resin. The weight ratio of the (meth)acrylate monomer to the tackifier is from 85:15 to 75:

25. The bismaleimide (c) is represented by formula (I): Where n represents an integer from 1 to 40, and R represents C1-C2. 12 Linear or at least partially cyclic divalent hydrocarbon group.

2. The adhesive composition according to claim 1, wherein the tackifier (b) has an acid value of 350 KOH mg / g or lower.

3. The adhesive composition according to claim 1 or 2, wherein the tackifier (b) has a softening point of 150°C or lower.

4. The adhesive composition according to claim 1 or 2, used for assembling a camera module or sensor.

5. Use of the adhesive composition according to any one of claims 1 to 3 for assembling camera modules or sensors.

6. A cured product, which can be obtained by curing an adhesive composition according to any one of claims 1 to 3.

7. A method for assembling a camera module or sensor, the method comprising bonding electronic components to a substrate using an adhesive composition according to any one of claims 1 to 3.

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