Solid crystal glue for LED and preparation method thereof

Abstract

The invention provides an LED (light-emitting diode) solid crystal adhesive and a preparation method thereof in order to solve the problems that volatile matters are generated in solvent dissolution and solidification when vinyl MQ resin is used as matrix resin to prepare the solid crystal adhesive in the prior art, or the solid crystal thrust is reduced or wire drawing and other undesirable phenomena occur when low-viscosity small-molecule vinyl silicone oil is used for dissolution. Comprising siloxane resin, a catalyst and a functional aid, the siloxane resin comprises first siloxane resin, second siloxane resin and third siloxane resin, the first siloxane resin comprises vinyl MQ resin, the second siloxane resin comprises organic hydrogen polysiloxane resin, and the third siloxane resin comprises organic hydrogen polysiloxane resin. The third siloxane resin comprises a compound as shown in a formula 1 (A3SiO1 / 2) x (A2ESiO1 / 2) 4-xSi formula 1, and x is a natural number from 0 to 3; a is selected from C1-C10 alkyl groups, and E is selected from C1-C10 alkenyl groups. The solid crystal glue for the LED, provided by the invention, is good in hardness, excellent in cohesiveness, relatively high in solid crystal thrust, moderate in viscosity, good in operability in a solid crystal process and low in volatilization amount during curing.

Description

Technical Field

[0001] The present invention relates to the technical field of die bonding adhesives, and particularly relates to a die bonding adhesive for LEDs and a preparation method thereof. Background Art

[0002] In recent years, light emitting diode devices (LEDs) have been gradually developing towards miniaturization, and the requirement for the adhesiveness of die bonding materials is getting higher and higher. The light emitting diode devices include silicone-based die bonding materials. If the adhesiveness of the die bonding materials is poor, serious problems such as chip peeling and inability to bond will occur in the subsequent wire bonding process of the light emitting diode devices. In order to improve the adhesiveness of silicone-based die bonding materials and ensure that the finally obtained die bonding adhesive has a high chip thrust, in the prior art, vinyl MQ resin with a three-dimensional network structure is usually used as the main resin. This vinyl MQ resin is usually solid at room temperature and is not suitable for direct use; if a solvent is used to dissolve the vinyl MQ resin, a large amount of volatile substances will be generated during the curing process. If these volatile substances are deposited on the chip electrode pads, it will affect the subsequent wire bonding step. If a linear low-viscosity small molecule vinyl silicone oil is used for dissolution, when a large amount of the low-viscosity small molecule vinyl silicone oil is added, the hardness and die bonding thrust of the generated die bonding material will decrease; when a small amount of the low-viscosity small molecule vinyl silicone oil is added, the viscosity of the generated die bonding material will be too high, resulting in poor phenomena such as wire drawing, glue throwing, and trailing during die bonding. Summary of the Invention

[0003] Aiming at the problems of the existing method for preparing a die bonding adhesive using vinyl MQ resin as the main resin, where volatile substances are generated during dissolution and curing with a solvent, or the die bonding thrust decreases or wire drawing and other poor phenomena occur when using a low-viscosity small molecule vinyl silicone oil for dissolution, the present application provides an LED die bonding adhesive and a preparation method thereof.

[0004] To solve the above problems, on the one hand, the present invention provides a die bonding adhesive for LEDs, which includes a siloxane resin, a catalyst, and a functional additive. The siloxane resin includes a first siloxane resin, a second siloxane resin, and a third siloxane resin. The first siloxane resin includes vinyl MQ resin, the second siloxane resin includes organohydrogenpolysiloxane resin, and the third siloxane resin includes a compound shown in Formula 1, (A3SiO 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si Formula 1 wherein, x is a natural number from 0 to 3; A is selected from C1-C10 alkyl groups, and E is selected from C2-C10 alkenyl groups.

[0005] Preferably, A is selected from C1-C5 alkyl groups, and E is selected from C2-C5 alkenyl groups.

[0006] Preferably, the vinyl MQ resin comprises one or more of the units shown in Formula 2, the units shown in Formula 3, and SiO 4 / 2 units; F3SiO 1 / 2 Formula 2, F2RSiO 1 / 2 Formula 3; wherein, F is selected from C1-C10 alkyl groups, and R is selected from C2-C10 alkenyl groups.

[0007] Preferably, the vinyl content in the vinyl MQ resin is 0.06 - 0.15 mol / 100 g.

[0008] Preferably, the organohydrogen polysiloxane comprises at least two hydrogen atoms bonded to silicon atoms; The organohydrogen polysiloxane resin comprises one or both of HMQ compounds and HMD compounds, The HMQ compound comprises one or more of the units shown in Formula 4, the units shown in Formula 5, and SiO 4 / 2 units; L3SiO 1 / 2 Formula 4, L2HSiO 1 / 2 Formula 5; The HMD compound comprises one or more of the units shown in Formula 4, the units shown in Formula 6, and the units shown in Formula 7; LHSiO 2 / 2 Formula 6, H2SiO 2 / 2 Formula 7; wherein, L is selected from C1-C10 alkyl groups.

[0009] Preferably, the number of hydrogen atoms bonded to silicon atoms in the organohydrogen polysiloxane resin is B1, and the total number of vinyl groups bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin is B2, and B1:B2 is (1 - 3):1.

[0010] Preferably, the die bonding adhesive comprises the following parts by weight: 30 - 100 parts of the first siloxane resin, 20 - 90 parts of the second siloxane resin, 10 - 100 parts of the third siloxane resin, and 1 - 50 parts of the functional additive; The weight of the catalyst is 1 - 100 ppm of the total weight of the first siloxane resin, the second siloxane resin, and the third siloxane resin.

[0011] Preferably, based on the parts by weight of the die bonding adhesive, the functional aids include 1 to 15 parts of tackifier, 0.01 to 5 parts of hydrosilylation reaction inhibitor, and 1 to 20 parts of thixotropic agent.

[0012] Preferably, the tackifier is an organosilicon polymer containing epoxy groups and vinyl groups; in the organosilicon polymer, the vinyl content is 0.05 to 1 mol / 100 g, and the epoxy equivalent is 200 to 600 g / eq; The catalyst includes platinum metal catalysts; The hydrosilylation reaction inhibitor includes alkynol compounds; The thixotropic agent includes hydrophobic fumed silica with a specific surface area of 150 to 300 m 2 / g.

[0013] In a second aspect, the present application provides a method for preparing the die bonding adhesive for LEDs described above, including the following steps: mixing the first siloxane resin, the second siloxane resin, the third siloxane resin, the catalyst, and the functional aids evenly to obtain the die bonding adhesive.

[0014] For the die bonding adhesive for LEDs provided by the present application, the Si-H bonds in the organohydrogenpolysiloxane resin can undergo a curing reaction with the vinyl groups bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin to form a structurally stable three-dimensional network structure, having the following effects: 1) good hardness and excellent adhesion, and a high chip thrust can be obtained after short-time curing, and a high die bonding thrust is achieved for both large-size and small-size chips; 2) moderate viscosity, good operability during the die bonding process, and no adverse phenomena such as wire drawing, glue splashing, and trailing; 3) and a low volatile matter content during curing, which will not cause adverse effects on subsequent wire bonding steps. Detailed Embodiments

[0015] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the following further describes the present invention in detail with reference to embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] To illustrate the technical solutions of the present invention, the following will be described through specific embodiments.

[0017] On the one hand, the present application provides a die bonding adhesive for LEDs, including siloxane resins, a catalyst, and functional aids. The siloxane resins include a first siloxane resin, a second siloxane resin, and a third siloxane resin. The first siloxane resin includes a vinyl MQ resin, the second siloxane resin includes an organohydrogenpolysiloxane resin, and the third siloxane resin includes a compound represented by Formula 1, (A3SiO 1 / 2) x (A2ESiO 1 / 2 ) 4-x Si Formula 1 Wherein, x is a natural number from 0 to 3; A is selected from C1-C10 alkyl groups, and E is selected from C2-C10 alkenyl groups.

[0018] Specifically, x is a natural number from 0 to 3. For example, x can be 0, 1, 2, or 3.

[0019] C1-C10 alkyl groups include straight-chain alkyl groups with 1 to 10 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, etc. C1-C10 alkyl groups can also be branched-chain alkyl groups with 1 to 10 carbon atoms, such as isobutyl, isopropyl, etc.

[0020] C2-C10 alkenyl groups include straight-chain alkenyl groups with 2 to 10 carbon atoms, such as vinyl, propenyl, CH=CHCH2CH3, 1-pentene, cis-2-pentene, trans-2-pentene, etc. C2-C10 alkenyl groups can also be branched-chain alkenyl groups with 2 to 10 carbon atoms, such as CH3CH2CH=C(CH3)CH2CH3, etc.

[0021] The die bonding adhesive for LEDs provided by this application does not use a solvent to dissolve vinyl MQ resin, produces few volatiles during curing, and will not cause adverse effects on subsequent wire bonding steps; the alkenyl groups in the first silicone resin and the third silicone resin react with the hydrogen in the second silicone to form a structurally stable three-dimensional network structure. This reaction has no by-products or small molecule release, and at the same time maintains a dense cross-linked network, making the reaction product have high hardness, low volatility, excellent adhesion, and the advantage of high die bonding thrust. Moreover, the viscosities of the second silicone and the third silicone are relatively low, and they have strong diluting ability, so that it is possible to achieve an extremely low viscosity without the need to add additional small molecule substances for dilution, thereby making the overall formulation viscosity moderate, and further reducing the volatiles during the curing process. With a moderate viscosity, the operability during the die bonding process is good, and there will be no adverse phenomena such as wire drawing, glue slinging, and trailing. Using the composition provided by this application in the die bonding process will not cause adverse effects on subsequent wire bonding.

[0022] In some preferred embodiments, A is selected from C1-C5 alkyl groups, and E is selected from C2-C5 alkenyl groups.

[0023] Specifically, A is preferably one or a combination of methyl, ethyl, propyl, and isopropyl, and A is more preferably methyl.

[0024] E is preferably one or a combination of vinyl, propenyl, and butenyl, and more preferably vinyl.

[0025] A is an alkyl group selected from C1-C5, and E is an alkenyl group selected from C2-C5. The prepared LED die bonding adhesive has higher adhesiveness and higher die bonding thrust, which is beneficial to the normal progress of the subsequent wire bonding process of the light-emitting diode device and avoids bad phenomena such as inability to bond.

[0026] In some preferred embodiments, x is 0.

[0027] When x is 0, the structural formula of the third silicone resin is (A2ESiO 1 / 2 )4Si. The generated LED die bonding adhesive has higher adhesiveness, less curing volatiles, moderate viscosity, and better operability during the die bonding process.

[0028] In some embodiments, the vinyl MQ resin includes one or more of the units shown in Formula 2, the units shown in Formula 3, and SiO 4 / 2 units; R'3SiO 1 / 2 Formula 2, R'2RSiO 1 / 2 Formula 3; wherein, R' is selected from alkyl groups of C1-C10, and R is selected from alkenyl groups of C2-C10.

[0029] Specifically, the vinyl MQ resin may be composed of siloxane units shown in Formula 2, or composed of units shown in Formula 3 and SiO 4 / 2 shown siloxane units, or composed of units shown in Formula 2, units shown in Formula 3, and SiO 4 / 2 shown siloxane units and other various composition methods.

[0030] The vinyl MQ resin can improve the bonding strength between the LED die bonding adhesive and the chip and the substrate, has good high-temperature resistance, and it can help the die bonding adhesive maintain its performance in a high-temperature environment; increase the elastic modulus and mechanical strength of the die bonding adhesive, and improve its ability to resist physical stress.

[0031] In some preferred embodiments, R' is selected from alkyl groups of C1-C5, and R is selected from alkenyl groups of C2-C5. The preferred ranges of R' and R of the vinyl MQ resin can make the bonding strength between the die bonding adhesive and the chip and the substrate stronger.

[0032] Further preferably, R' is selected from methyl, and R is selected from vinyl.

[0033] In some embodiments, the vinyl content in the vinyl MQ resin is 0.06-0.15 mol / 100 g.

[0034] The vinyl content in the vinyl MQ resin is 0.06 - 0.15 mol / 100 g. Specifically, it means that in 100 g of the vinyl MQ resin, the molar content of vinyl is 0.06 - 0.15 mol, which can provide better flexibility and elasticity and improve the mechanical properties such as hardness of the die-bonding adhesive.

[0035] The vinyl MQ resin is a white solid at 25 °C.

[0036] In some embodiments, the organohydrogen polysiloxane includes at least two hydrogen atoms bonded to silicon atoms; The organohydrogen polysiloxane resin includes one or both of the HMQ compound and the HMD compound. The HMQ compound includes one or more of the units shown in Formula 4, the units shown in Formula 5, and the SiO 4 / 2 units; L3SiO 1 / 2 Formula 4 L2HSiO 1 / 2 Formula 5; The HMD compound includes one or more of the units shown in Formula 4, the units shown in Formula 6, and the units shown in Formula 7; LHSiO 2 / 2 Formula 6 H2SiO 2 / 2 Formula 7; wherein, L is selected from C1 - C10 alkyl groups.

[0037] Specifically, the organohydrogen polysiloxane includes at least two hydrogen atoms bonded to silicon atoms, and is selected from one or both of the HMQ compound and the HMD compound. It can undergo an addition curing reaction under the action of a platinum metal catalyst, react with the vinyl MQ resin and the compound shown in Formula 1 to form a three-dimensional network structure, and improve the mechanical properties, thermal stability and adhesion properties of the die-bonding adhesive.

[0038] L is selected from C1 - C10 alkyl groups, including straight-chain alkyl groups with 1 - 10 carbon atoms or branched alkyl groups with 1 - 10 carbon atoms; C1 - C10 alkyl groups can be, for example, methyl, ethyl, propyl or isopropyl.

[0039] In some embodiments, the viscosity of the organohydrogen polysiloxane resin is 1 - 500 cp, and the hydrogen content is 0.6 - 2 mol / 100 g.

[0040] Specifically, the viscosity of the organohydrogen polysiloxane resin ranges from 1 to 500 cp, ensuring that the die bonding adhesive has appropriate fluidity and wetting ability during preparation. A resin with a moderate viscosity can better fill the tiny gaps between microelectronic components, ensuring good bonding effects. The hydrogen content of the organohydrogen polysiloxane resin is 0.6 - 2 mol / 100g, controlling the rate and degree of the curing reaction, optimizing the crosslinking density of the cured product, and thus obtaining ideal mechanical properties and thermal stability.

[0041] In some embodiments, the number of hydrogen atoms bonded to silicon atoms in the organohydrogen polysiloxane resin is B1, and the total number of vinyl groups bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin is B2, and B1:B2 is (1 - 3):1.

[0042] Specifically, when B1:B2 is limited to the range of (1 - 3):1, the Si - H bonds in the organohydrogen polysiloxane resin can undergo a curing reaction with the vinyl groups bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin, forming a three - dimensional network structure with stable structure, improving the adhesiveness of the die bonding adhesive, having a high die bonding thrust, improving the viscosity of the die bonding adhesive, and reducing the volatiles during curing.

[0043] The value of B1:B2 can be 1:1, 1.2:1, 1.4:1, 1.8:1, 2.0:1, 2.3:1, 2.5:1, 2.8:1, or 3.0:1, etc., as long as B1:B2 is within the range of (1 - 3):1.

[0044] In some embodiments, the die bonding adhesive comprises the following parts by weight: 30 - 100 parts of the first siloxane resin, 20 - 90 parts of the second siloxane resin, 10 - 100 parts of the third siloxane resin, and 1 - 50 parts of the functional additive; the weight part of the catalyst is 1 - 100 ppm of the total weight parts of the first siloxane resin, the second siloxane resin, and the third siloxane resin.

[0045] Specifically, with the contents of the components added to the die bonding adhesive as above, it is beneficial for the Si - H bonds in the organohydrogen polysiloxane resin to undergo a curing reaction with the vinyl groups bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin under the action of the catalyst and the functional additive, cross - linking to form a three - dimensional network structure with stable structure, improving the hardness and bonding performance of the die bonding adhesive, having less volatiles during the curing process, and having a high die bonding thrust.

[0046] In some embodiments, based on the parts by weight of the die bonding adhesive, the functional additive comprises 1 - 15 parts of a tackifier, 0.01 - 5 parts of a silicon hydrosilylation reaction inhibitor, and 1 - 20 parts of a thixotropic agent.

[0047] Specifically, 1 to 15 parts of tackifier are used to increase the adhesion performance between the die bonding adhesive and the chip. 0.01 to 5 parts of the silicon hydrosilylation reaction inhibitor are used to inhibit the formation of silane bonds during the silanization reaction; this inhibitor reduces or prevents the formation of silane bonds by competing with silicon-hydrogen bonds or silane bonds in the reaction.

[0048] 1 to 20 parts of thixotropic agent can improve the viscosity of the die bonding adhesive, making the die bonding adhesive easy to operate and process. In some embodiments, the tackifier is an organosilicon polymer containing epoxy groups and vinyl groups; the catalyst includes platinum metal-based catalysts; The silicon hydrosilylation reaction inhibitor includes alkynol compounds; The thixotropic agent includes hydrophobic fumed silica with a specific surface area of 150 to 300 m 2 / g.

[0049] In some preferred embodiments, in the organosilicon polymer, the vinyl content is 0.05 to 1 mol / 100 g, and the epoxy equivalent is 200 to 600 g / eq; Specifically, the vinyl content in the tackifier is 0.05 to 1 mol / 100 g, and the epoxy equivalent is 200 to 600 g / eq, which helps to improve the adhesion and cohesion of the die bonding adhesive, thereby enhancing its bonding effect on the chip substrate.

[0050] In every 100 g of the organosilicon polymer, the vinyl content can be 0.05 mol, 0.1 mol, 0.15 mol, 0.2 mol, 0.3 mol, 0.4 mol, 0.5 mol, 0.6 mol, 0.8 mol, 1.0 mol, etc., as long as it is within the range of 0.05 to 1 mol / 100 g. In every 100 g of the organosilicon polymer, the epoxy equivalent can be in the following ranges: 200 to 300 g / eq, 300 to 400 g / eq, 400 to 500 g / eq, 500 to 600 g / eq, as long as the epoxy group content is within the range of 200 to 600 g / eq.

[0051] In a second aspect, the present application provides a method for preparing the die bonding adhesive for LED as described above, including the following steps: mixing the first silicone resin, the second silicone resin, the third silicone resin, the catalyst, and the functional auxiliary agent evenly to obtain the die bonding adhesive.

[0052] The method for preparing the die bonding adhesive for LED provided by the present application has a simple process and low cost.

[0053] In some embodiments, a method for preparing a die-bonding adhesive for LEDs includes the following steps: First, mix the first siloxane resin and the third siloxane resin evenly, then add a thixotropic agent and mix evenly to obtain a first mixture. Add the second siloxane resin, a tackifier, and a hydrosilylation reaction inhibitor to the first mixture and mix evenly to obtain a second mixture. Add a catalyst to the second mixture and mix evenly to obtain the die-bonding adhesive.

[0054] The present invention will be further described below through examples.

[0055] Example 1 S1: Prepare the die-bonding adhesive: First, mix 100 parts of the first siloxane resin and 10 parts of the third siloxane resin evenly, then add 6 parts of the thixotropic agent and mix evenly to obtain a first mixture. Add 20 parts of the second siloxane resin, 4 parts of the tackifier, and 0.5 part of the hydrosilylation reaction inhibitor to the first mixture and mix evenly to obtain a second mixture. Add 0.01 part of the catalyst to the second mixture and mix evenly to obtain the die-bonding adhesive.

[0056] Among them, the first siloxane resin is (Me3SiO 1 / 2 ) 0.3 (Me2ViSiO 1 / 2 ) 0.1 (SiO 4 / 2 ) 0.6 , and the vinyl content is 0.14 mol / 100 g; The second siloxane resin is (Me2HSiO 1 / 2 ) 0.75 (SiO 4 / 2 ) 0.25 , with a viscosity of 37 cp and a hydrogen content of 1.2 mol / 100 g; The third siloxane resin is (A3SiO 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si, where A is selected from methyl, x is 0, and E is selected from vinyl; The tackifier is (Me2ViSiO 1 / 2 ) 0.1 (MeEpSiO 2 / 2 ) 0.4 (MeSiO 3 / 2 ) 0.4 , with a vinyl content of 0.12 mol / 100 g and an epoxy equivalent of 215 g / eq; Ep is an epoxy group, Me is methyl, and Vi is vinyl; The hydrosilylation reaction inhibitor is 1-ethynylcyclohexanol; The thixotropic agent has a specific surface area of 200 m 2Hydrophobic fumed silica of / g; The catalyst is platinum metal. Examples 2 - 9 and Comparative Examples 1 - 3 Examples 2 - 9 and Comparative Examples 1 - 3 have most of the steps the same as those of Example 1, the difference being that the components of the first siloxane resin, the second siloxane resin, the third siloxane resin, the tackifier, the hydrosilylation reaction inhibitor, and the thixotropic agent added are different, as shown in Table 1 specifically.

[0057] In Comparative Examples 1, 2, and 3, the third siloxane resin was not added. Among them, in Comparative Example 2, vinyl silicone oil was added, and vinyl silicone oil was used to dissolve the first siloxane resin. In Comparative Example 3, toluene was added, and toluene solvent was used to dissolve the first siloxane resin.

[0058] Table 1 Example 10 This example has most of the steps the same as those of Example 1, the difference being that the third siloxane resin is (A3SiO 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si, where A is selected from methyl, x is 1, and the rest is the same as that of Example 1.

[0059] Example 11 This example has most of the steps the same as those of Example 1, the difference being that the third siloxane resin is (A3SiO 1 / 2 ) x (A2ESiO 1 / 2 ) 4-x Si, where A is selected from methyl, x is 3, and the rest is the same as that of Example 1.

[0060] Performance test The LED die bonding adhesives prepared in the above examples and comparative examples were subjected to the following tests: 1) Viscosity test: At 25 °C, the prepared LED die bonding adhesive was tested for its viscosity using a brookfield cap2000 + cone - plate viscometer according to the instructions.

[0061] 2) Volatile content: Weigh 1 g ± 0.1 g of the glue, and test the weight ratio loss before and after curing at 170 °C for 1 h; 3) Wire drawing and glue flinging during die bonding: The equipment used is the NeoChips dual-head high-speed die bonder GTS100 BH-PA, with a die bonding rate of 50k / h. LED chips of 10×30mil and 8×15mil are bonded to 2835 brackets. For each type of die bonding glue and each type of chip, one bracket (the 2835 bracket has a specification of 16×36, a total of 576 pieces) is die bonded. The brackets with die bonded chips are observed under a microscope to count the proportion of residual glue left on the brackets and the upper part of the chips due to glue flinging.

[0062] 4) Thrust test: The brackets with die bonded chips are cured at 170°C for 1h, and the force standard LB-8100A is used to test the thrust value when the chips are pushed away.

[0063] The test results are shown in Table 2.

[0064] Table 2 As can be seen from Table 1 and Table 2, when comparing Examples 1-2 with Comparative Examples 1-3, Comparative Examples 1-3 do not have the third siloxane resin of the compound shown in Structural Formula 1. In Comparative Example 1, vinyl MQ resin is not dissolved with a solvent and vinyl silicone oil, and Comparative Example 1 cannot be cured and crystallized. In Comparative Example 2, vinyl silicone oil is used as a solvent to dissolve vinyl MQ resin, and the volatilization amount is slightly lower, but the die bonding thrust is low. In Comparative Example 3, toluene is used as a solvent to dissolve vinyl MQ resin, and the volatilization amount is higher, and the die bonding thrust is low. It shows that by using the LED die bonding glue provided in this application, vinyl MQ resin is not dissolved with a solvent, the volatilization amount generated during curing is low, and it will not cause adverse effects on the subsequent wire bonding step. At the same time, it contains the first siloxane resin, the second siloxane resin and the third siloxane resin, forming a three-dimensional network structure with a stable structure. This reaction has no by-products or small molecule release, and at the same time maintains a dense cross-linked network, making the reaction product have high hardness, low volatilization amount, excellent adhesion, and the advantage of high die bonding thrust.

[0065] Comparing Example 1 and Example 4, the content of the first silicone resin is less than 30 to 100 parts, the viscosity of the die bonding glue is low, and the high thrust of die bonding is relatively low. It is speculated that because the content of the first silicone resin is too low, the content of the hydrosilylation reaction with the hydrogen in the second silicone decreases, the stability of the formed three-dimensional network structure decreases, the hardness of the die bonding glue decreases, and the adhesion between the die bonding glue and the bracket decreases. Comparing Example 1 with Example 5 and 7, the content of the third silicone resin is less than 10 to 100 parts, the viscosity of the die bonding glue is too high, and wire drawing or glue throwing occurs; when the content of the third silicone resin is higher than 10 to 100 parts, the viscosity of the die bonding glue is lower, wire drawing or glue throwing occurs, and the die bonding thrust is lower. Comparing Example 1 with Example 6 and 8, in Example 6, the content of the second silicone resin is higher than 20 to 90 parts, the viscosity of the die bonding glue is low, the volatilization amount increases, and the die bonding thrust is lower; in Example 8, the content of the second silicone resin is less than 20 to 90 parts, the viscosity of the die bonding glue is high, and the die bonding thrust is lower. Through the above comparisons and the data of Examples 1-3 and Example 9, it can be concluded that in the die bonding glue for LEDs, there are 30 to 100 parts of the first silicone resin, 20 to 90 parts of the second silicone resin, and 10 to 100 parts of the third silicone resin. The alkenyl groups in the first silicone resin and the third silicone resin undergo hydrosilylation reactions with the hydrogen in the second silicone to form a three-dimensional network structure with stable structure. The obtained die bonding glue has high hardness, low volatilization amount, excellent adhesion, and the advantage of high die bonding thrust.

[0066] In Examples 10-11, when the third silicone functional group changes, the thrust also changes significantly. mainly when the ratio or functional group of the first silicone, the second silicone, and the third silicone changes, the content of vinyl and hydrogen in the composition changes, resulting in a change in the density of the crosslinked network, thus affecting the thrust. Moreover, the viscosities of the second silicone and the third silicone are low, and changes in their content will cause changes in the viscosity of the composition, affecting the construction performance.

[0067] The above examples are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing examples, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A die-bonding adhesive for LED, characterized in that: The invention comprises a siloxane resin, a catalyst and a functional auxiliary agent, wherein the siloxane resin comprises a first siloxane resin, a second siloxane resin and a third siloxane resin, wherein the first siloxane resin comprises a vinyl MQ resin, the second siloxane resin comprises an organohydrogen polysiloxane resin, and the third siloxane resin comprises a compound represented by Formula 1. <h2 style=";text-align:left;direction:ltr">(A3SiO<h2 style=";text-align:left;direction:ltr"> 1 / 2 <h2 style=";text-align:left;direction:ltr"> )<h2 style=";text-align:left;direction:ltr"> x <h2 style=";text-align:left;direction:ltr"> (A2ESiO<h2 style=";text-align:left;direction:ltr"> 1 / 2 <h2 style=";text-align:left;direction:ltr"> )<h2 style=";text-align:left;direction:ltr"> 4-x <h2 style=";text-align:left;direction:ltr"> Si and 1 Where x is a natural number from 0 to 3; A is selected from C1~C10 alkyl, and E is selected from C2~C10 alkenyl.

2. The LED die-bonding adhesive according to claim 1, characterized in that: A is selected from C1~C5 alkyl, and E is selected from C2~C5 alkenyl.

3. The LED die-bonding adhesive according to claim 1, characterized in that: The vinyl MQ resin includes a unit shown in Formula 2, a unit shown in Formula 3, SiO 4 / 2 One or more of the units; R'3SiO 1 / 2 Formula 2, R'2RSiO 1 / 2 Formula 3; Wherein, R' is selected from C1~C10 alkyl, and R is selected from C2~C10 alkenyl.

4. The LED die-bonding adhesive according to claim 1, characterized in that: The vinyl content of the vinyl MQ resin is 0.06-0.15 mol / 100g.

5. The LED die-bonding adhesive according to claim 1, characterized in that: The organohydrogenpolysiloxane includes at least two hydrogen atoms bonded to silicon atoms; The organohydrogenpolysiloxane resin includes one or both of a HMQ compound and a HMD compound, The HMQ compound includes a unit shown in Formula 4, a unit shown in Formula 5, SiO 4 / 2 One or more of the units; L3SiO 1 / 2 Formula 4, LqCy 1 / 2 Formula 5; The HMD compound includes one or more units shown in Formula 4, Formula 6, and Formula 7; LqCy 2 / 2 Formula 6, H2SiO 2 / 2 Formula 7; Wherein, L is selected from C1~C10 alkyl groups.

6. The LED die-bonding adhesive according to claim 1, characterized in that: The number of hydrogen atoms bonded to silicon atoms in the organohydrogenpolysiloxane resin is B1, the total number of vinyl groups bonded to silicon atoms in the vinyl MQ resin and the third siloxane resin is B2, and B1:B2 is (1-3):

1.

7. The LED die-bonding adhesive according to claim 1, characterized in that: The solid crystal adhesive comprises the following parts by weight: 30-100 parts of a first silicone resin, 20-90 parts of a second silicone resin, 10-100 parts of a third silicone resin, and 1-50 parts of a functional additive; The weight of the catalyst is 1-100 ppm based on the total weight of the first siloxane resin, the second siloxane resin and the third siloxane resin.

8. The LED die-bonding adhesive according to claim 7, characterized in that: Based on the weight of the die-bonding adhesive, the functional additives include 1 to 15 parts of a tackifier, 0.01 to 5 parts of a hydrosilylation reaction inhibitor, and 1 to 20 parts of a thixotropic agent.

9. The LED die-bonding adhesive according to claim 8, characterized in that: The tackifier is an organic silicon polymer, and the organic silicon polymer contains epoxy groups and vinyl groups; in the organic silicon polymer, the vinyl content is 0.05-1 mol / 100 g, and the epoxy equivalent is 200-600 g / eq; The catalyst includes a platinum metal catalyst; The hydrosilylation reaction inhibitor includes an acetylenic alcohol compound; The thixotropic agent includes a specific surface area of ​​150 to 300 m 2 / g of hydrophobic fumed silica.

10. A method for preparing a die-bonding adhesive for LED according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: uniformly mixing a first siloxane resin, a second siloxane resin, a third siloxane resin, a catalyst and a functional auxiliary agent to obtain the solid crystal adhesive.

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