CN111303813A - Room temperature curing pouring sealant for precise electronic components and use method thereof - Google Patents

Abstract

The invention discloses a room temperature curing pouring sealant for electronic components and a use method thereof, and relates to the technical field of electronic component protection. The pouring sealant comprises a component A, a component B and a component C; the component A is prepared by mixing 100 parts of modified epoxy resin, 1-10 parts of reactive diluent, 1-5 parts of accelerant and 0.5-3 parts of coupling agent in parts by weight; the component B is an amine curing agent; the component C is a solvent-free nanofluid. The pouring sealant disclosed by the invention has the characteristics of low viscosity, high impact strength, high adhesive force, high dynamic mechanical strength, low linear expansion coefficient and the like, and is excellent in comprehensive performance.

Description

A room temperature curing potting glue for precision electronic components and using method thereof

technical field

The invention relates to the technical field of protection of electronic components in the electronic industry, in particular to a room temperature curing potting glue for precision electronic components and a method for using the same.

Background technique

With its excellent comprehensive properties, epoxy resin cured products are often used in the field of potting of electronic components, which can strengthen the integrity of electronic devices, improve the resistance to external shock and vibration, and improve internal components or circuits. insulation. However, due to the brittleness, poor impact resistance, high internal stress and easy cracking of epoxy resin, the reliability of epoxy potting products for precision electronic components with complex structures has been greatly affected.

The research on epoxy resin potting materials by domestic and foreign research institutions generally only focuses on static performance, and rarely involves research on dynamic performance. In fact, some special precision electronic systems have extremely high performance requirements for the materials used in the potting protection of their electronic components, especially epoxy resin materials, including the raw material viscosity of the potting glue, the bonding performance to the device, the material impact strength, dynamic mechanical strength and coefficient of linear expansion.

For the potting of precision electronic components, the curing temperature of epoxy resin is generally required to be as low as possible to avoid damage to precision electronic components during high-temperature curing, and the heat release during the curing process must be considered, as well as the comprehensive mechanical properties of the cured product. . However, most of the epoxy potting compounds researched and developed at present are either high temperature potting compounds or general performance. )≤2500mPa∙s, the curing temperature is as high as 70℃~120℃; for example, the highest curing temperature experienced in the preparation process of epoxy potting adhesive in Chinese patent application 201210288422.4 is as high as 105℃; Preparation and performance research of , Bonding, 2019, 18-21) reported a room temperature curing epoxy potting adhesive with a viscosity of up to 8000-21500 mPa∙s, which is worth mentioning. For precision electronic components potting, Poor fluidity will greatly reduce the gap filling and protection of electronic components; another example is the ring reported by Zhuang Mian et al. The impact strength of oxygen potting sealant is only 10-15MPa, and its performance is average.

SUMMARY OF THE INVENTION

In view of the above-mentioned defects and deficiencies in the prior art, the present invention provides a room temperature curing potting compound for precision electronic components, which is especially suitable for the protection requirements of precision electronic components. The purpose of the invention of the present invention is to solve "the potting glue in the prior art cannot meet the performance requirements of the potting of precision electronic components". The potting glue of the invention has the characteristics of low viscosity, high impact strength, high adhesive force, high dynamic mechanical strength, low linear expansion coefficient, etc., and has excellent comprehensive performance.

In order to solve the problems existing in the above-mentioned prior art, the present invention is realized by the following technical solutions:

A room temperature curing potting glue for precision electronic components is characterized in that: it includes component A, component B and component C, and in parts by weight, said component A is formed by mixing the following components :

100 parts of modified epoxy resin, 1-10 parts of reactive diluent, 1-5 parts of accelerator, 0.5-3 parts of coupling agent; the component B is an amine curing agent; the component C is a solvent-free nanofluids.

The modified epoxy resin is one or more of polyurethane modified CYD-128 epoxy resin, liquid carboxyl-terminated nitrile modified CYD-128 epoxy resin and hyperbranched epoxy modified CYD-128 epoxy resin. combination of species.

The diluent is a reactive diluent with an epoxy group, specifically one of 662# epoxy diluent, 669# epoxy diluent, 632# epoxy diluent and 636# epoxy diluent or various combinations.

The accelerator is an epoxy room temperature curing accelerator, specifically one or more of 2-ethyl-4-methylimidazole accelerator, 2,4,6-tris[(dimethylamino)methyl]phenol. kind of combination.

The coupling agent is a silane coupling agent, specifically γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropoxytrimethoxysilane and γ-methyl A combination of one or more of acryloxypropyltrimethoxysilane.

The amine curing agent is a combination of one or more of alicyclic amine curing agent, aliphatic amine curing agent and polyetheramine curing agent.

The solvent-free nanofluids are solvent-free _TiO nanofluids, solvent-free CaCO nanofluids, solvent _- free SiO nanofluids, solvent _- free ZnO nanofluids, solvent-free carbon black nanofluids, solvent-free graphene nanofluids and solvent-free nanofluids A combination of one or more of carbon nanotube nanofluids.

The invention also provides a method for using the room temperature curing potting glue for precision electronic components. The potting glue of the present invention can be cured at room temperature, and its viscosity, bonding performance, impact strength, dynamic compression yield strength And the linear expansion coefficient can meet the high-performance potting protection requirements of electronic components, and the comprehensive performance is excellent.

A method for using room temperature curing potting glue for precision electronic components, characterized in that: after mixing and stirring 100 parts of component A, 15-35 parts of component B and 0.5-10 parts of component C, Vacuum defoaming treatment, curing at room temperature for 12h-96h.

Further, the preferred technical solution of the present invention is as follows: after 100 parts of component A, 20-30 parts of component B and 0.5-5 parts of component C are mixed and stirred uniformly, vacuumed and defoamed, and cured at room temperature. 36h-72h.

Compared with the prior art, the beneficial technical effects brought by the present invention are shown in:

1. The potting glue of the present invention can achieve the following performance indicators: (1) Viscosity: 1500 mPa∙s-2400 mPa∙s at 25°C, which can be adjusted by the type of diluent and the amount added, (2) Gel time: 6-8h, which can be adjusted by the type and amount of accelerator, (3) Shear strength: ≥12MPa (aluminum and aluminum), ≥12MPa (epoxy resin board and epoxy resin board), (4) Tensile strength: ≥ 60MPa (5) Dynamic compressive yield strength ≥190MPa (strain rate ≥1000s ^-1 ), (6) Impact strength ≥70MPa; (7) Linear expansion coefficient ≤6.0×10 ^-5 ℃ ^-1 .

2. A room temperature curing potting glue for electronic components with room temperature curability selected in the present invention, the formula of component A in the raw material is polyurethane/liquid carboxyl-terminated nitrile/hyperbranched with strong toughness unit For epoxy resins composed of units such as epoxy, the curing agent itself also considers alicyclic amines/aliphatic amines/polyetheramines with strong toughness units, and on this basis introduces low viscosity/high dispersion. The functional/functional solvent-free nanofluidic filler, through the optimized design of components, exhibits excellent toughness and good adhesion of epoxy resin encapsulant under the organic coordination of the three, and the introduction of solvent-free nanofluid The linear expansion coefficient of the epoxy resin material can be reduced to a certain extent. On the basis of these key three components, reactive diluents with epoxy groups/epoxy room temperature curing accelerators/silane coupling agents are introduced to further reduce the viscosity of the resin raw material system/to improve the curing efficiency/improvement The effect of adhesive properties.

3. In the present invention, some solvent-free nanofluids have excess amine groups remaining, so they will participate in the epoxy resin curing process as a function similar to a curing agent, and can promote the curing reaction. Nanofluids have the characteristics of monodispersity and fluidity near room temperature. Therefore, the introduction into epoxy resin systems will not increase the viscosity of the resin. On the contrary, the introduction of solvent-free nanofluids with lower viscosity will reduce the viscosity of the resin system to a certain extent. (The introduction of nanoparticles will increase the viscosity of the system), because of its good dispersibility, it can be dispersed very uniformly in epoxy resin materials, and a small amount of solvent-free nanofluids can be added to play a large modification effect. (Although the introduction of nanoparticles will bring a certain modification effect, but because of its easy agglomeration, it will cause stress concentration inside the material, so that the mechanical properties of the resin material will be significantly reduced when the amount of nanoparticles added increases, or the modification effect is not obvious). And some solvent-free nanofluids can participate in the epoxy resin curing reaction due to the presence of incompletely grafted -OH on the surface of the nanoparticles or the outer organic matter grafted on the solvent-free nano-surface contains some active terminal amine groups during the preparation process. Epoxy resin composites showed better properties, such as the incompletely grafted -OH on the surface during the preparation of solvent-free _SiO2 nanofluids would increase the crosslinking point of chemical reaction and decrease the reaction temperature. At the same time, the polyetheramine in the fluid outer layer also contains a large number of active terminal amine groups, which can also provide cross-linking sites for epoxy resins.

Detailed ways

The technical solutions of the present invention will be further elaborated below with reference to each embodiment.

In this embodiment, a room temperature curing potting compound for precision electronic components includes component A, component B and component C, in parts by weight, the component A is represented by the following Table 1 components are mixed.

Table 1 shows the composition and amount of component A.

In the room temperature curing potting glue for precision electronic components, component B is an amine curing agent; the component C is a solvent-free nanofluid. Wherein, the modified epoxy resin is one of polyurethane modified CYD-128 epoxy resin, liquid carboxyl-terminated nitrile modified CYD-128 epoxy resin and hyperbranched epoxy modified CYD-128 epoxy resin or a combination of multiple; the diluent is a reactive diluent with epoxy groups, specifically 662# epoxy diluent, 669# epoxy diluent, 632# epoxy diluent and 636# epoxy diluent A combination of one or more of the agents.

The accelerator is an epoxy room temperature curing accelerator, specifically one or more of 2-ethyl-4-methylimidazole accelerator, 2,4,6-tris[(dimethylamino)methyl]phenol. combination of species.

The coupling agent is a silane coupling agent, specifically γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropoxytrimethoxysilane and γ-methyl A combination of one or more of acryloxypropyltrimethoxysilane.

The amine curing agent is a combination of one or more of alicyclic amine curing agent, aliphatic amine curing agent and polyetheramine curing agent.

The solvent-free nanofluids are solvent-free _TiO nanofluids, solvent-free CaCO nanofluids, solvent _- free SiO nanofluids, solvent _- free ZnO nanofluids, solvent-free carbon black nanofluids, solvent-free graphene nanofluids and solvent-free nanofluids A combination of one or more of carbon nanotube nanofluids.

The preparation method of the solvent-free nano-TiO ₂ fluid is as follows: the surface hydroxylated nano-TiO ₂ is grafted with a quaternized silane coupling agent, and then prepared by ion exchange with the polyoxyethylene functionalized organic long chain.

The preparation method of solvent _- free CaCO3 nanofluids is (Li Q et al. J Am Chem Soc, 2009, 131(26): 9148-9149): the number of hydroxyl groups on the surface is increased under specific chemical conditions, and then a silane coupling agent is used After grafting technology, solvent-free calcium carbonate nanofluids can be prepared.

The preparation method of solvent _- free SiO nanofluid is as follows: using the Stober method, using absolute ethanol, ammonia water, deionized water, methanol and ethyl orthosilicate at room temperature to prepare solid SiO nano _- microspheres with different particle sizes, and using KH560 to prepare the polymer. Etheramines (monoamines, diamines or triamines) were grafted on the surface of _SiO2 to prepare solvent-free _SiO2 nanofluids. Alternatively, the surface of SiO ₂ particles is first treated with an acidic silane coupling agent, and then neutralized with NaOH to form a salt. After reacting at 70 °C for 24 h, the sodium ions are removed through a particle exchange column and fully protonated. PEG-functionalized tertiary amines were subjected to acid-base reaction to prepare solvent-free _SiO2 nanofluids.

The preparation method of solvent-free ZnO nanofluid is as follows: firstly, Zn(OH) ₂ is prepared by reacting NaOH and ZnCl ₂ , then reacting with bromoacetic acid to obtain zinc bromoacetate, and then reacting with N,N-dimethyloctadecyl The corresponding quaternary ammonium salt is obtained by the reaction of amine, followed by anion exchange with quinine sulfate to obtain zinc ionic liquid, and finally reacted with LiOH to obtain ZnO ionic liquid, which is solvent-free ZnO nanofluid.

The preparation method of solvent-free carbon black nanofluid is as follows: firstly, the original carbon black is subjected to strong acid oxidation treatment, then the organic ion salt of carbon black is obtained by grafting with silane coupling agent DC5700, and finally ion exchange with PEG-functionalized nitrate is carried out to prepare Solvent-free carbon black nanofluids with liquid-like behavior were developed.

The preparation method of solvent-free graphene nanofluid is as follows: using the spontaneous transfer mechanism of graphene surface electrons to diazonium salts to graft diazonium salts to the graphene surface to obtain sulfonated graphene, through flexible long-chain ions and graphene ions The exchange obtains the diazo compound graft, and finally the solvent-free graphene fluid is obtained.

The preparation method of the solvent-free carbon nanotube nanofluid is as follows: the solvent-free carbon nanotube nanofluid is prepared by acid-base reaction of octadecylamine polyoxyethylene ether and acid-oxidized carbon nanotube. Alternatively, KH560 coupling agent is used to graft polyetheramine (monoamine, diamine or triamine) on the surface of carbon nanotubes to prepare corresponding solvent-free carbon nanotube nanofluids.

The invention also provides a method for using room temperature curing potting glue for precision electronic components. The linear expansion coefficient can meet the requirements of special electronic components, and the comprehensive performance is excellent.

A method of using a room temperature curing potting glue for precision electronic components. Treatment, curing at room temperature for 12h-96h.

Further, the preferred technical solution of the present invention is as follows: after 100 parts of component A, 20-30 parts of component B and 0.5-5 parts of component C are mixed and stirred uniformly, vacuumed and defoamed, and cured at room temperature. 36h-72h. Wherein component A selects any proportioning in above-mentioned embodiment 1-7 for use, and concrete proportioning embodiment is as shown in table 2 below:

Table 2 shows the proportions and performance parameters of components A, B and C.

For the different ratios of Component A, Component B and Component C, after mixing at room temperature, the viscosity is measured using a rotational viscometer, measured according to GB/T 22314-2008, Example 8-Example 12 The viscosity test results of different ratios are shown in the table above; after mixing Component A and Component B according to the above-mentioned proportions of Examples 1-7, they were cured at room temperature and passed through the bonding between the aluminum plates and between the resin plates respectively. The adhesion of the adhesive was tested, and the shear strength was tested. The test results obtained are shown in the table above (shear strength: using a universal testing machine, measured according to the GB/T 7124-86 adhesive tensile shear strength test standard). The test of linear expansion coefficient is obtained according to GB/T 1036-89 plastic linear expansion coefficient measurement method; the test of dynamic compressive yield strength mainly adopts the Hopkinson compression bar test system, by changing the incident rod and projection rod in contact with the test The shape of the end of the sample can generate compression wave, tensile shear wave or compression shear wave inside the sample, and based on the one-dimensional elastic wave theory, it can be obtained according to the stress-strain relationship of the material at different strain rates. The specific test results are shown in Table 2 above.

It can be seen from the above table that the potting compound provided by the present invention can achieve the following properties: (1) Viscosity: 1500mPa∙s-2400 mPa∙s at 25°C, which can be adjusted by the type of diluent and the amount added, (2) Gel Time: 6-8h, can be adjusted by the type and amount of accelerator, (3) Shear strength: ≥12MPa (aluminum and aluminum), ≥12MPa (epoxy resin board and epoxy resin board), (4) Tensile strength : ≥60MPa (5) Dynamic compressive yield strength ≥190MPa (strain rate ≥1000s ^-1 ), (6) Impact strength ≥70MPa; (7) Linear expansion coefficient ≤6.0×10 ^-5 ℃ ^-1 .

In this application, a set of comparative experiments is also proposed, that is, the component C of this application is replaced with nanoparticles, and the performance test of the potting compound after component A, component B and nanoparticles are mixed. The test method is the same as The above test methods are the same. The obtained experimental results are shown in Table 3 below.

Table 3 shows the performance parameters after replacing the solvent-free nanofluids of component C with nanoparticles.

It can be seen from the above Table 2 and Table 3 that in this application, the solvent-free nanofluid can effectively reduce the viscosity of the potting compound, and the shear strength, tensile strength, dynamic compressive yield strength and impact strength are all improved, and the coefficient of linear expansion is improved. somewhat reduced.

Some of the solvent-free nanofluids in the present invention have excess amine groups remaining, so they will participate in the epoxy resin curing process as a function similar to a curing agent, and can promote the curing reaction. Nanofluids have the characteristics of monodispersity and fluidity near room temperature. Therefore, the introduction into epoxy resin systems will not increase the viscosity of the resin. On the contrary, the introduction of solvent-free nanofluids with lower viscosity will reduce the viscosity of the resin system to a certain extent. (The introduction of nanoparticles will increase the viscosity of the system), because of its good dispersibility, it can be dispersed very uniformly in epoxy resin materials, and a small amount of solvent-free nanofluids can be added to play a larger modification effect ( Although the introduction of nanoparticles will bring good modification effect, due to its easy agglomeration, it will cause stress concentration inside the material, which will lead to some mechanical properties of the resin material will be significantly reduced when the amount of nanoparticles added increases, or the modification effect is not obvious ). In the preparation process of some solvent-free nanofluids, due to the incompletely grafted -OH on the surface of the nanoparticles or the outer organic matter grafted on the solvent-free nano-surface contains some active terminal amine groups, they can participate in the curing reaction of epoxy resin, making the ring Oxygen resin composites show better performance, such as the incompletely grafted -OH on the surface of the solvent-free _SiO2 nanofluid during the preparation process will increase the chemical reaction cross-linking point, reduce the reaction temperature, and at the same time in the fluid outer layer polyetheramine It also contains a large number of active terminal amine groups, which can also provide cross-linking sites for epoxy resins.

Claims (9)

1. A room temperature curing potting glue for precision electronic components, characterized in that: comprising component A, component B and component C, in parts by weight, the component A is mixed by the following components resulting in: 100 parts of modified epoxy resin, 1-10 parts of reactive diluent, 1-5 parts of accelerator, 0.5-3 parts of coupling agent; the component B is an amine curing agent; the component C is a solvent-free nanofluids. 2. A room temperature curing potting glue for precision electronic components as claimed in claim 1, characterized in that: the modified epoxy resin is polyurethane modified CYD-128 epoxy resin, liquid carboxyl-terminated butadiene A combination of one or more of nitrile-modified CYD-128 epoxy resin and hyperbranched epoxy-modified CYD-128 epoxy resin. 3. A room temperature curing potting glue for precision electronic components as claimed in claim 1, characterized in that: the diluent is a reactive diluent with epoxy groups, specifically 662# epoxy A combination of one or more of diluent, 669# epoxy diluent, 632# epoxy diluent and 636# epoxy diluent. 4. A room temperature curing potting glue for precision electronic components as claimed in claim 1, characterized in that: the accelerator is an epoxy room temperature curing accelerator, specifically 2-ethyl-4-methyl One or more combinations of imidazole accelerator and 2,4,6-tris[(dimethylamino)methyl]phenol. 5. A room temperature curing potting glue for precision electronic components as claimed in claim 1, characterized in that: the coupling agent is a silane coupling agent, specifically γ-aminopropyl triethoxy A combination of one or more of gamma-aminopropyltrimethoxysilane, gamma-aminopropyltrimethoxysilane, gamma-aminopropoxytrimethoxysilane, and gamma-methacryloxypropyltrimethoxysilane. 6. A room temperature curing potting glue for precision electronic components as claimed in claim 1, wherein the amine curing agent is alicyclic amine curing agent, aliphatic amine curing agent and polyether A combination of one or more of the amine curing agents. 7. A room temperature curing potting glue for precision electronic components as claimed in claim 1, wherein the solvent-free nanofluid is a solvent-free _TiO nanofluid, a solvent-free CaCO nanofluid, a solvent _- free nanofluid, A combination of one or more of solvent-free SiO nanofluids, solvent _- free ZnO nanofluids, solvent-free carbon black nanofluids, solvent-free graphene nanofluids, and solvent-free carbon nanotube nanofluids. 8. A method for using room temperature curing potting glue for precision electronic components, characterized in that: after mixing 100 parts of component A, 15-35 parts of component B and 0.5-10 parts of component C, evenly , after vacuum defoaming treatment, curing at room temperature for 12h-96h. 9. The method for using a room temperature curing potting glue for precision electronic components as claimed in claim 8, wherein 100 parts of component A, 20-30 parts of component B and 0.5-5 parts of After component C is mixed and stirred evenly, it is vacuumed and defoamed, and cured at room temperature for 36h-72h.