Easily ceramized dealcoholized silicone adhesive as well as preparation method and application thereof

Abstract

The invention provides a dealcoholized silicone adhesive easy to ceramize and a preparation method thereof, the method belongs to the technical field of sealing materials, and the dealcoholized silicone adhesive easy to ceramize comprises the following components: a base adhesive, a filler, a cross-linking agent, a coupling agent and a catalyst. The composite filler formed by the melamine polyphosphate, the cobalt salt and the carbon nanotubes is added into an easily ceramized dealcoholized silicone adhesive system, so that the easily ceramized dealcoholized silicone adhesive system can be easily ceramized at the temperature of 500 DEG C, and combustion is blocked.

Description

Technical Field

[0001] This invention belongs to the field of sealing materials technology, and relates to an easily ceramicized and de-alcoholized silicone sealant, its preparation method, and its application. Background Technology

[0002] In the packaging of power batteries and the fabrication and assembly of microelectronic devices, adhesives play an irreplaceable role, with basic functions including structural bonding, mechanical fixation, electrical insulation, thermal conductivity, sealing, protection, flame retardancy, and high-temperature stability. With the rapid development of the new energy vehicle industry, the safety performance of power batteries, as their core component, is of paramount importance. The newly revised mandatory national standard GB 38031—2025, "Safety Requirements for Power Batteries for Electric Vehicles," will come into effect in July 2026. This standard includes requirements for single-cell thermal runaway triggering, stipulating that the power battery system must not catch fire or explode within a certain timeframe, and that the smoke concentration after thermal runaway must not obstruct the driver's vision. Thermal runaway is one of the main safety hazards of power batteries, posing a threat to the lives of drivers and passengers. While traditional silicone sealants possess excellent bonding performance and weather resistance, their insufficient flame retardancy makes it difficult to meet the high safety requirements of power batteries. Therefore, developing a de-alcoholized silicone sealant with excellent bonding strength, rapid ceramization at high temperatures, and high residual carbon strength is an urgent problem to be solved in this field. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide an easily ceramicized, alcohol-free silicone sealant, its preparation method, and its applications.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] On one hand, the present invention provides an easily ceramizable and de-alcoholized silicone sealant, the easily ceramizable and de-alcoholized silicone sealant comprising the following components in parts by weight:

[0006] Base adhesive 10-40 parts, filler 50-100 parts, crosslinking agent 1-5 parts, catalyst 0.1-2 parts, coupling agent 0.1-3 parts;

[0007] The fillers include composite fillers (Co@MPP / CNTs) formed from melamine polyphosphate, cobalt salt, and carbon nanotubes, as well as other inorganic fillers.

[0008] In this invention, the amount of base adhesive used in the easily ceramicized de-alcoholized silicone sealant can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc.

[0009] In this invention, the amount of filler used in the easily ceramicized de-alcoholized silicone sealant can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, etc.

[0010] In this invention, the amount of crosslinking agent in the easily ceramicized de-alcoholized silicone sealant can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

[0011] In this invention, the amount of catalyst used in the easily ceramicized de-alcoholized silicone sealant can be 0.1 parts, 0.3 parts, 0.5 parts, 0.7 parts, 0.9 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, etc.

[0012] In this invention, the amount of coupling agent used in the easily ceramizable and alcohol-free silicone sealant can be 0.1 parts, 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 1.8 parts, 2 parts, 2.3 parts, 2.7 parts, 3 parts, etc.

[0013] Preferably, in the easily ceramizable de-alcoholized silicone sealant, the content of the composite filler formed by melamine polyphosphate, cobalt salt and carbon nanotubes is 2-15 parts, such as 2 parts, 5 parts, 8 parts, 10 parts, 12 parts or 15 parts.

[0014] Preferably, the composite filler formed from melamine polyphosphate, cobalt salt, and carbon nanotubes is prepared by the following method:

[0015] (I) An aqueous solution containing melamine polyphosphate and cobalt salt is reacted at 30-60℃ (30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, etc.) to obtain Co@MPP powder;

[0016] (II) Carbon nanotubes and activator are added to a solvent and dispersed. Then Co@MPP powder is added, stirred, and filtered to obtain the composite filler.

[0017] Preferably, the reaction time in step (I) is 3-12 hours, such as 3 hours, 5 hours, 7 hours, 10 hours or 12 hours.

[0018] Preferably, the aqueous solution containing melamine polyphosphate and cobalt salt is obtained by the following method: adding melamine polyphosphate to water, heating to 30-50℃ (30℃, 33℃, 35℃, 38℃, 40℃, 42℃, 45℃, 47℃, 49℃, 50℃, etc.), stirring for 20-50 min (e.g., 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, or 50 min) to obtain an aqueous solution of melamine polyphosphate; dispersing cobalt salt in water to obtain an aqueous solution of cobalt salt; adding the aqueous solution of cobalt salt to the aqueous solution of melamine polyphosphate, stirring evenly to obtain the aqueous solution containing melamine polyphosphate and cobalt salt.

[0019] Preferably, the carbon nanotubes in step (II) are carbon nanotubes that have undergone carboxylation modification.

[0020] Preferably, the stirring time in step (II) is 5-24h (5h, 8h, 10h, 15h, 18h, 20h, 22h, 24h, etc.).

[0021] Preferably, step (II) further includes washing and drying steps after filtration.

[0022] Preferably, the other fillers include calcium carbonate, glass powder, mica powder, and aluminum hydroxide. The amount of calcium carbonate is 3-15 parts (3 parts, 5 parts, 8 parts, 10 parts, 12 parts, 14 parts, 15 parts, etc.), the amount of glass powder is 0.2-3 parts (0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.3 parts, 1.6 parts, 1.9 parts, 2.5 parts, 2.7 parts, 3 parts, etc.), the amount of mica powder is 1-10 parts (1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.), and the amount of aluminum hydroxide is 30-60 parts (30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, etc.).

[0023] Preferably, the α,ω-dihydroxy polysiloxane is composed of α,ω-dihydroxy polysiloxanes of different viscosities. Based on the total mass of the α,ω-dihydroxy polysiloxanes being 100%, the contents of the α,ω-dihydroxy polysiloxanes of different viscosities are as follows:

[0024] 10-15% (e.g., 10%, 12%, 14% or 15%) of hydroxyl-terminated polydimethylsiloxane with a concentration of 1000-2000 cp (e.g., 1000 cp, 1200 cp, 1500 cp, 1800 cp or 2000 cp).

[0025] 25% to 45% (e.g., 25%, 28%, 30%, 35%, 40% or 45%) of hydroxyl-terminated polydimethylsiloxane with a strength of 4500 to 5500 cp (e.g., 4500 cp, 4800 cp, 5000 cp, 5300 cp or 5500 cp);

[0026] 50-65% (e.g., 50%, 53%, 55%, 58%, 60%, 63% or 65%) of 20,000 to 80,000 cp (e.g., 20,000 cp, 30,000 cp, 40,000 cp, 50,000 cp, 70,000 cp or 80,000 cp) of hydroxyl-terminated polydimethylsiloxane.

[0027] Preferably, the crosslinking agent is selected from methyltrimethoxysilane and / or methyltriethoxysilane.

[0028] Preferably, the catalyst is selected from titanium catalysts.

[0029] Preferably, the coupling agent is selected from KH550 and / or KH560.

[0030] Preferably, the preparation method of the easily ceramizable and de-alcoholized silicone sealant includes the following steps:

[0031] The base adhesive and filler are mixed and then reacted. After cooling, a crosslinking agent, a catalyst, and a coupling agent are added and mixed to obtain the easily ceramicized dealcoholized silicone adhesive.

[0032] Preferably, the reaction temperature is 80℃~100℃, such as 80℃, 82℃, 85℃, 88℃, 90℃, 93℃, 96℃, 99℃, 100℃, etc.

[0033] Preferably, the reaction is carried out under a vacuum pressure of -0.08 to -0.1 MPa (-0.08 MPa, -0.085 MPa, -0.09 MPa, -0.093 MPa, -0.096 MPa, -0.098 MPa, -0.1 MPa, etc.).

[0034] Preferably, the reaction is carried out under stirring.

[0035] Preferably, the reaction time is 90~180 min (90 min, 100 min, 120 min, 140 min, 150 min, 170 min, 180 min, etc.).

[0036] Preferably, the cooling is to a temperature of 50~80℃, for example, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃.

[0037] Preferably, the crosslinking agent, catalyst, and coupling agent are added and mixed under normal pressure for 30-60 min (30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.), and then mixed under vacuum pressure of -0.08 to -0.1 MPa (-0.08 MPa, -0.085 MPa, -0.09 MPa, -0.093 MPa, -0.096 MPa, -0.098 MPa, -0.1 MPa, etc.) for 20-40 min (20 min, 25 min, 28 min, 30 min, 33 min, 35 min, 37 min, 40 min, etc.).

[0038] On the other hand, the present invention provides the application of the easily ceramizable and alcohol-free silicone sealant as described above in power battery packaging and microelectronic devices.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] This invention incorporates a composite filler formed from melamine polyphosphate, cobalt salt, and carbon nanotubes into an easily ceramizable, alcohol-free silicone sealant system, enabling the resulting silicone sealant to be easily ceramizable at 500°C and preventing combustion. Detailed Implementation

[0041] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0042] Example 1 of the preparation of Co@MPP / CNTs packing

[0043] In this preparation example, the Co@MPP / CNTs packing was prepared according to the following method:

[0044] 30.4 g of MPP (melamine polyphosphate, CAS No.: 218768-84-4) was added to 1000 mL of deionized water, heated to 40 °C, and stirred for 30 min to obtain a uniformly dispersed solution. Simultaneously, 20.8 g of Co(NO3)2·6H2O was dispersed in 500 mL of deionized water. The Co(NO3)2·6H2O aqueous solution was slowly added dropwise to the MPP solution, and stirring continued for 5 h after the addition was complete. The stirred solution was transferred to a polytetrafluoroethylene reactor and placed in a 60 °C oven for 12 h. After the reaction was completed, the solution was removed, cooled, washed, and dried to obtain Co@MPP powder.

[0045] 40g of CNTs, 20g of EDS, and 20g of NHS were added to 1000mL of ethanol-water solution and ultrasonically dispersed for 30min. Then, 40g of Co@MPP powder was added, and the mixture was stirred for 12h. After filtration, washing, and drying, the Co@MPP / CNTs filler was obtained. The resulting filler was a black powder with good dispersibility and thermal stability, and could be used to prepare ceramicized de-alcoholized silicone sealants.

[0046] Preparation Examples 2 to 6 were used to prepare a Co@MPP / CNTs filler. The difference between this and Preparation Example 1 was the different ratio of the raw materials used, as shown in Table 1. In Preparation Example 6, no CNT raw material was used, and Co@MPP powder was prepared instead.

[0047] Table 1 Formulation table for preparation examples 1-6

[0048]

[0049] Note: In Preparation Example 4, Co(NO3)2·6H2O was not used, and the prepared Co@MPP did not contain Co. Its accurate expression should be Co0@MPP1, that is, a single MPP. In Preparation Example 5, MPP was not used, and the Co@MPP described therein should be accurately expressed as Co1@MPP0.

[0050] Example 1, an easily ceramizable and alcohol-free silicone sealant, was prepared according to the following method:

[0051] After mixing α,ω-dihydroxy polysiloxane, calcium carbonate, mica powder, aluminum hydroxide, and Co@MPP / CNTs, the temperature was adjusted to 100℃, the vacuum pressure was -0.08MPa, and the mixture was stirred for 180 min. Then, the mixture was cooled down, and a crosslinking agent, catalyst, and coupling agent were added under normal pressure and stirred for 60 min. Finally, the mixture was stirred under a vacuum pressure of -0.08MPa for 30 min to obtain the easily ceramicized de-alcoholized silicone sealant.

[0052] The α,ω-dihydroxy polysiloxane used in the following examples was obtained by mixing 107 base adhesives with viscosities of 1500, 5000, 20000, and 80000 cp from Hesheng in proportions of 5 parts, 80 parts, 10 parts, and 5 parts, respectively.

[0053] Table 2 Formulation Tables for Examples 1 to 6

[0054]

[0055] Table 3 Formulation Tables for Examples 7 to 11

[0056]

[0057] Table 4 Formulation Tables for Examples 12-16

[0058]

[0059] Performance testing

[0060] 1. Tensile property testing: The tensile strength and elongation at break of the easily ceramizable and alcohol-free silicone rubber obtained in the examples were tested according to the relevant instructions in GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0061] 2. The flame retardant properties of the rubber were tested by vertical burning according to standard UL94-2009. The sample size was 200 mm × 50 mm × 0.2 mm, and it was wound longitudinally on a rod and held vertically. The density of the ceramic body under high temperature conditions was tested according to GB / T25992-2010 Precision Ceramics Density Test Method. The sample size was 5 mm × 10 mm × 10 mm.

[0062] Table 4 Comparison of rubber properties in specific embodiments

[0063]

[0064] Comparing Examples 2, 3 and 1, the ratio of MPP to Co(NO3)2·6H2O in the preparation of Co@MPP / CNTs was determined. The change in the ratio of more MPP to less MPP had little effect on the tensile strength and elongation at break of the silicone sealant, and had no effect on the flame retardant rating. In addition, compared with Example 1, the density of the ceramic body decreased slightly after ceramization.

[0065] Comparing Example 4 and Example 1, Co@MPP / CNTs without Co(NO3)2·6H2O showed significantly reduced tensile strength and elongation at break, a decrease in flame retardant rating from V0 to V1, and a decrease in ceramic density. Adding Co(NO3)2·6H2O can disperse MPP particles, resulting in more uniform Co@MPP, preventing agglomeration, and enabling the formation of a dense ceramic body during ceramicization, thus increasing the ceramic body density.

[0066] Comparing Example 5 and Example 1, Co@MPP / CNTs, which do not contain MPP, exhibit significantly reduced tensile strength and elongation at break, a lower flame retardant rating (V0 to V2), and a decrease in ceramic density. MPP decomposes at high temperatures and can react with inorganic fillers such as mica and glass powder in the formulation, thereby lowering the eutectic melting point.

[0067] Comparing Example 6 and Example 1, Co@MPP / CNTs without CNTs showed significantly reduced tensile strength and elongation at break, a decrease in flame retardancy rating from V0 to V1, and a decrease in ceramic density. Adding CNTs can improve the thermal stability and tensile properties of silicone sealant.

[0068] Compared with Example 1, when 10 parts of Co@MPP / CNTs were transferred to aluminum hydroxide without Co@MPP / CNTs, the tensile strength and elongation at break were significantly reduced, the flame retardant rating was reduced from V0 to V2, and the ceramic density decreased.

[0069] Comparing Example 8 with Example 1, transferring 10 parts of Co@MPP / CNTs-free calcium carbonate significantly reduced tensile strength and elongation at break, lowered the flame retardant rating from V0 to V2, and decreased the ceramization density. Comparing Example 8 with Example 7, adding calcium carbonate increased elongation at break but decreased tensile strength and ceramization density compared to adding aluminum hydroxide.

[0070] Comparing Examples 9, 10, and 11 with Example 1, it can be found that as the content of Co@MPP / CNTs increases, the elongation at break, tensile strength, flame retardancy rating, and density of the ceramic body after ceramization are all improved. However, the improvement is not significant when the content is greater than 10 parts.

[0071] Comparing Example 12 with Example 1, increasing the proportion of calcium carbonate and decreasing the proportion of base adhesive will increase the tensile strength but will significantly reduce the elongation at break, reduce the flame retardant rating from V0 to V1, and reduce the density of the ceramicized body.

[0072] Comparing Example 13 with Example 1, reducing the proportion of calcium carbonate and increasing the proportion of base adhesive will increase the elongation at break but will reduce the tensile strength significantly, the flame retardant rating will decrease from V0 to V2, and the density of the ceramicized body will decrease.

[0073] Compared with Example 1, reducing the proportion of crosslinking agent in Example 14 slightly reduced the elongation at break, tensile strength, and density of the ceramicized body.

[0074] Compared with Example 1, Example 15 reduced the catalyst ratio, resulting in a slight decrease in elongation at break, tensile strength, and density of the ceramicized body.

[0075] Compared with Example 1, Example 16 increased the proportion of coupling agent, which slightly reduced the elongation at break, tensile strength and density of the ceramicized body.

[0076] The applicant declares that this invention illustrates the easily ceramizable, alcohol-free silicone sealant, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A type of easily ceramizable and alcohol-free silicone sealant, characterized in that, The easily ceramizable and alcohol-free silicone sealant comprises the following components in parts by weight: Base adhesive 10-40 parts, filler 50-100 parts, crosslinking agent 1-5 parts, catalyst 0.1-2 parts, coupling agent 0.1-3 parts; The filler includes composite fillers formed from melamine polyphosphate and cobalt salts and carbon nanotubes, as well as other inorganic fillers.

2. The easily ceramizable and alcohol-free silicone sealant according to claim 1, characterized in that, The content of the composite filler formed by melamine polyphosphate, cobalt salt and carbon nanotubes in the easily ceramicized dealcoholized silicone sealant is 2-15 parts.

3. The easily ceramizable and alcohol-free silicone sealant according to claim 1 or 2, characterized in that, The composite filler formed from melamine polyphosphate, cobalt salt, and carbon nanotubes was prepared by the following method: (I) An aqueous solution containing melamine polyphosphate and cobalt salt is reacted at 30-60℃ to obtain Co@MPP powder; (II) Carbon nanotubes and activator are added to a solvent and dispersed. Then Co@MPP powder is added, stirred, and filtered to obtain the composite filler.

4. The easily ceramizable and alcohol-free silicone sealant according to claim 3, characterized in that, The reaction time in step (I) is 3-12 hours; Preferably, the aqueous solution containing melamine polyphosphate and cobalt salt is obtained by the following method: adding melamine polyphosphate to water, heating to 30-50°C, and stirring for 20-50 minutes to obtain an aqueous solution of melamine polyphosphate; dispersing cobalt salt in water to obtain an aqueous solution of cobalt salt; adding the aqueous solution of cobalt salt to the aqueous solution of melamine polyphosphate, and stirring evenly to obtain the aqueous solution containing melamine polyphosphate and cobalt salt. Preferably, the carbon nanotubes in step (II) are carboxylated modified carbon nanotubes; Preferably, the stirring time in step (II) is 5-24 hours; Preferably, step (II) further includes washing and drying steps after filtration.

5. The easily ceramizable and alcohol-free silicone sealant according to claim 1, characterized in that, The other fillers include calcium carbonate, glass powder, mica powder, and aluminum hydroxide. The amount of calcium carbonate is 3-15 parts, the amount of glass powder is 0.2-3 parts, the amount of mica powder is 1-10 parts, and the amount of aluminum hydroxide is 30-60 parts.

6. The easily ceramizable and alcohol-free silicone sealant according to any one of claims 1-5, characterized in that, The base adhesive includes α,ω-dihydroxypolysiloxane; Preferably, the α,ω-dihydroxy polysiloxane is composed of α,ω-dihydroxy polysiloxanes of different viscosities. Based on the total mass of the α,ω-dihydroxy polysiloxanes being 100%, the contents of the α,ω-dihydroxy polysiloxanes of different viscosities are as follows: 10-15% hydroxyl-terminated polydimethylsiloxane with a viscosity of 1000-2000 cp; 25-45% of hydroxyl-terminated polydimethylsiloxane with a viscosity of 4500-5500 cp; Hydroxyl-terminated polydimethylsiloxane with a concentration of 20,000–80,000 cp, comprising 50–65%; Preferably, the crosslinking agent is selected from methyltrimethoxysilane and / or methyltriethoxysilane; Preferably, the catalyst is selected from titanium catalysts; Preferably, the coupling agent is selected from KH550 and / or KH560.

7. The method for preparing the easily ceramizable and alcohol-free silicone sealant according to any one of claims 1-6, characterized in that, The preparation method includes the following steps: The base adhesive and filler are mixed and then reacted. After cooling, a crosslinking agent, a catalyst, and a coupling agent are added and mixed to obtain the easily ceramicized dealcoholized silicone adhesive.

8. The preparation method according to claim 7, characterized in that, The reaction temperature is 80℃~100℃; Preferably, the reaction is carried out under a vacuum pressure of -0.08 to -0.1 MPa; Preferably, the reaction is carried out under stirring; Preferably, the reaction time is 90-180 min.

9. The preparation method according to claim 7, characterized in that, The cooling refers to reducing the temperature to 50~80℃; Preferably, the crosslinking agent, catalyst and coupling agent are added and mixed under normal pressure for 30-60 min, and then mixed under vacuum pressure of -0.08 to -0.1 MPa for 20-40 min.

10. The application of the easily ceramizable and de-alcoholized silicone sealant according to any one of claims 1-6 in power battery packaging and microelectronic devices.

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