Equal-proportion semitransparent bi-component dealcoholization type organic silicon sealant for electric kettle and preparation method and application of equal-proportion semitransparent bi-component dealcoholization type organic silicon sealant

Abstract

The invention discloses an equal-proportion semitransparent bi-component dealcoholization type organic silicon sealant for an electric kettle as well as a preparation method and application of the equal-proportion semitransparent bi-component dealcoholization type organic silicon sealant. The organosilicon sealant comprises a component A and a component B, the component A comprises hydroxyl-terminated polydimethylsiloxane, a reinforcing filler, a curing accelerator, a plasticizer and a catalyst, and the component B comprises polyalkoxy silicon-based terminated polydimethylsiloxane, a reinforcing filler, a plasticizer, a cross-linking agent and an adhesive. The silicone rubber has the advantages that the components are environment-friendly, and the silicone rubber can be used as food contact type silicone rubber; the rapid and uniform deep curing of the sealant can be realized; the water boiling-resistant adhesion property and the yellowing resistance of the cured colloid are very strong; the operation and use are easy. Therefore, the organic silicon sealant is used for preparing the electric kettle.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicone materials, and particularly relates to an isometric semi-transparent two-component alcohol-free silicone sealant for electric kettles, a preparation method thereof, and an application thereof. Background Art

[0002] Electric kettles are widely used in daily life and mainly consist of a bottom heating plate, a kettle body, and other accessories. Currently, a sealing silicone bonding solution is mainly used for bonding the bottom heating plate and the kettle body. In addition, the large-scale, automated, and efficient production of electric kettles also places increasingly high demands on the curing performance of the sealant. A faster curing speed and bonding speed are required to match the rapid turnover needs of the production line.

[0003] Currently, the sealants applied to bond the bottom heating plate and the kettle body are mainly room-temperature-curing one-component condensation-type silicone and addition-curing silicone sealant. Due to its curing mechanism, the curing speed of one-component condensation-type silicone is restricted by both temperature and humidity, and the curing speed is slow. It cannot be cured deeply, and it takes three to seven days to be completely cured, which cannot meet the high-efficiency requirements of the automated production line. The addition-curing liquid silicone belongs to non-polar rubber. The elastomer after its curing and molding exhibits extremely low cohesive energy, and the entire molecular chain is non-polar, while the surfaces of most substrates are polar. Therefore, the addition-curing liquid silicone has weak bonding performance, and generally needs to be cured above 120 °C to have good adhesiveness. Therefore, when applied to bond an electric kettle, a high-temperature baking tunnel needs to be provided, which has high requirements for the production site, capital investment, and subsequent energy costs. Moreover, in order to solve the defect of weak adhesiveness of the addition-curing silicone, a primer solution is usually applied on-site or the substrate is treated with plasma to improve its adhesiveness to the substrate. The primer contains volatile solvents, which have a negative impact on environmental protection and the production line environment. And adopting the plasma treatment process increases the equipment investment and energy costs. Patent applications CN109401669A and CN110894420A both adopt addition-curing bonding sealants, which are suitable for the application scenario of water-boiling bonding and can be used for the bonding and sealing of the bottom heating plate and the kettle body. Both adopt heat-curing bonding, and the heating temperature exceeds 120 °C, with high energy and equipment investment, which does not conform to the current development trend of energy conservation and consumption reduction. Patent application CN1115521625A uses an adhesive containing acyloxy and epoxy groups as a tackifier for the addition-curing kettle glue, which can quickly bond to the substrate under the conditions of low temperature 60 °C and 30 min, and has a relatively excellent water-boiling bonding retention rate, but still requires heat curing to promote bonding.

[0004] Condensation two-component room temperature vulcanizing (RTV-2) silicone sealant generally uses an organotin catalyst and has the characteristic of fast curing speed, which is more suitable for bonding and sealing in the automated production industry. Currently, for commercially available two-component condensation silicone sealants, the mixing ratio of components A and B is any ratio between 4:1 and 20:1. When in use, it has high requirements for the metering accuracy of the mixing equipment. Moreover, when the mixing ratio fluctuates, it is easy to cause instability in the various properties of the silicone sealant, and even uncuring phenomenon may occur, thus restricting its application in certain fields. In addition, organotin compounds are highly toxic. According to the EU Directive 2009 / 425 / EC, since July 1, 2010, the EU has restricted the use of organotin in all consumer products to less than 0.1%; since January 1, 2012, dibutyltin with a tin content exceeding 0.1% shall not be used in mixtures or articles supplied to the public. Among them, single-component and two-component RTV sealants and adhesives have also been restricted since January 1, 2015. In addition, the use of organotin compounds is explicitly prohibited in food-contact silicone rubber.

[0005] Therefore, developing a two-component condensation silicone sealant for electric kettles, which can cure rapidly at room temperature, bond quickly, mix in equal proportions, does not contain an organotin catalyst, conforms to the development trend of energy conservation, consumption reduction and high-efficiency turnover in automated production, is convenient to use on-site, and is friendly to humans and the environment, has important social significance and a clear market development prospect. Summary of the Invention

[0006] The primary object of the present invention is to overcome the disadvantages and deficiencies of the prior art and provide an equal-proportion semi-transparent two-component alcohol-free silicone sealant for electric kettles.

[0007] Another object of the present invention is to provide a preparation method for the above-mentioned equal-proportion semi-transparent two-component alcohol-free silicone sealant for electric kettles.

[0008] A further object of the present invention is to provide the application of the above-mentioned equal-proportion semi-transparent two-component alcohol-free silicone sealant for electric kettles.

[0009] The object of the present invention is achieved by the following technical solutions: An equal-proportion semi-transparent two-component alcohol-free silicone sealant for electric kettles, comprising component A and component B;

[0010] Component A comprises the following components by mass parts: 100 parts of hydroxyl-terminated polydimethylsiloxane, 5 - 20 parts of reinforcing filler, 1 - 4 parts of curing accelerator, 0 - 14 parts of plasticizer, 0.2 - 1.0 part of catalyst;

[0011] Component B comprises the following components by mass parts: 100 parts of polyalkoxysilyl-terminated polydimethylsiloxane, 5 - 18 parts of reinforcing filler, 0 - 10 parts of plasticizer, 3 - 10 parts of crosslinking agent, 2 - 5 parts of adhesive.

[0012] The structural formula of the hydroxyl-terminated polydimethylsiloxane is HO[(CH3)2SiO] n H, and its viscosity at 25 °C is 750 - 30000 mPa·S, preferably 1500 - 20000 mPa·S. The hydroxyl-terminated polydimethylsiloxane can be a single component or a mixture of at least two components.

[0013] The polyalkoxysilyl-terminated polydimethylsiloxane is prepared by condensation and alcohol elimination of hydroxyl-terminated polydimethylsiloxane with polyalkoxysilane, or by hydrosilylation reaction of polyalkoxysilane with a poly(dimethylsiloxane) having unsaturated bonds at the end groups. This polymer is not prone to polycondensation reaction with crosslinking agents and adhesives in a closed system, and plays an important role in the storage stability of component B. Its viscosity at 25 °C is 750 - 30000 mPa·S, preferably 1500 - 20000 mPa·S. The polyalkoxysilyl-terminated polydimethylsiloxane can be a single component or a mixture of at least two components.

[0014] The polyalkoxy group is preferably trimethoxy or methyldimethoxy.

[0015] The reinforcing filler in component A and component B can be at least one of fillers such as fumed silica and hydrophobic silica; preferably hydrophobic silica.

[0016] The specific surface area of the hydrophobic silica is preferably 100 - 300 m 2 / g.

[0017] The catalyst is a strontium carboxylate. Compared with common organotin catalysts, its catalytic activity is slightly lower, but it is safe, environmentally friendly and will not cause any harm to the human body. Such catalysts are preferably at least one of strontium isooctanoate and strontium neodecanoate.

[0018] The curing accelerator is precipitated silica, preferably with a specific surface area of 100 - 200 m 2Precipitated silica at 0 g. Compared with fumed silica, precipitated silica has a high surface hydroxyl content. The existing states include not only isolated hydroxyls, but also ortho and double states. Water molecules are easily adsorbed on the surface of silica by forming hydrogen bonds with -OH on the surface of carbon black. More ortho hydroxyls are adsorbed, and several molecular layers can be adsorbed at room temperature. The water content of fumed silica is about 1.5%, and the water content of precipitated silica is 4 - 8%. The reaction process of two-component condensation type alcohol-eliminating silica gel crosslinking and curing requires the participation of water. The presence of trace water in the system can increase the curing reaction rate. The relatively high water content and specific surface area of precipitated silica promote the rapid progress of the condensation reaction. The advantage of the present invention lies in the combined use of strontium catalyst and precipitated silica in the polymer composition. Due to the relatively high specific surface area of precipitated silica, it can adsorb alcohol from the polycondensation equilibrium reaction, resulting in a large shift of the equilibrium reaction. This leads to a synergistic reaction, where a strontium catalyst with slightly lower catalytic activity combines with precipitated silica to achieve rapid and uniform deep curing of the condensation type kettle glue in the present invention. When the layer thickness is more than 8 mm, the entire colloid can be cured uniformly and rapidly, while avoiding the use of environmentally unfriendly highly active organotin catalysts.

[0019] The plasticizer described is preferably dimethyl silicone oil, and its viscosity at 25 °C is preferably 50 - 1000 mPa·s.

[0020] The crosslinking agent described is preferably selected from at least one of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, hydrolyzed oligomer of ethyl silicate, methyltrimethoxysilane, methyltriethoxysilane, polymethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, polymethyltriethoxysilane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(methyldimethoxysilyl)ethane, and 1,2-bis(methyldiethoxysilyl)ethane.

[0021] The adhesive described is at least one of the adhesives with the structural formula shown as A1 and the adhesive with the structural formula shown as A2.

[0022]

[0023] Among them, R1 and R2 are CH3 or C2H5, and R1 and R2 can be the same or different.

[0024] Y is

[0025] The adhesive described is preferably prepared through the following steps:

[0026] (1) Under the protection of inert gas, after uniformly mixing the amino silane and the silane end-capping agent, the temperature is raised to 60-70 °C, and then cyclohexene oxide silane is added dropwise. Stir evenly at a constant speed, control the reaction temperature at 60-70 °C, and control the dropping time within 1-2 hours;

[0027] (2) After the dropping is completed, keep the temperature for reaction for 1-2 hours, then raise the temperature to 80-90 °C and turn on the vacuum pump. Control the vacuum degree at -0.09 to -0.1 MPa to remove the generated alcohol and the unreacted silane end-capping agent to obtain the adhesive.

[0028] The silane end-capping agent is preferably at least one of methyltrimethoxysilane and phenyltrimethoxysilane.

[0029] The amino silane is preferably at least one of aminopropyltrimethoxysilane and aminopropyltriethoxysilane.

[0030] The cyclohexene oxide silane is preferably at least one of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0031] The dosage of the amino silane and the silane end-capping agent is preferably in a molar ratio of 1:2.

[0032] The dosage of the amino silane and the cyclohexene oxide silane is preferably in a molar ratio of 1:1 to 1:1.5.

[0033] The time of the heat preservation reaction is preferably 1.5-2 hours.

[0034] The preparation method of the above-mentioned equal-proportion translucent two-component alcohol-free silicone sealant for electric kettles includes the following steps:

[0035] (1) Preparation of component A:

[0036] ① Use a dynamic mixer to uniformly mix the hydroxyl-terminated polydimethylsiloxane, reinforcing filler, curing accelerator and plasticizer. The revolution speed is 20-40 Hz, the dispersion speed is 20-40 Hz, and then control the material temperature not exceeding 80 °C and stir for 1-2 h;

[0037] ② Cool the material finally obtained in step ① to below 45 °C, then add the catalyst, with a revolution speed of 10-30 Hz and a dispersion speed of 10-30 Hz, stir for 20-40 min, and use cooling water to control the material temperature not exceeding 40 °C. Then continue to stir for 10-30 min for defoaming under vacuum conditions, with a vacuum degree of -0.08 to -0.10 MPa. Finally, discharge to obtain component A and store it sealed;

[0038] (2) Preparation of component B:

[0039] ① Mix the polyalkoxy-terminated polydimethylsiloxane and the reinforcing filler evenly with a dynamic mixer at a revolution speed of 20 - 40 HZ and a dispersion speed of 20 - 40 HZ. Meanwhile, heat the material to 100 - 130 °C, and stir for 1 - 2 h under a vacuum of -0.08 to -0.10 MPa.

[0040] ② Cool the material obtained in step ① to below 45 °C, add the plasticizer, and stir at a revolution speed of 10 - 30 HZ and a dispersion speed of 10 - 30 HZ for 20 - 40 min. Then, add the crosslinking agent and the adhesive in sequence, stir at a revolution speed of 10 - 30 HZ and a dispersion speed of 10 - 30 HZ, and control the material temperature not to exceed 40 °C with cooling water. Meanwhile, evacuate the air, with a vacuum of -0.08 to -0.10 MPa, and stir for 30 - 60 min. Finally, discharge to obtain component B and store it sealed.

[0041] Application of the above-mentioned equal-proportion translucent two-component alcohol-free silicone sealant for electric kettles in the preparation of electric kettles; preferably, it includes the following steps: Mix component A and component B in a mass ratio or volume ratio of 1:1.

[0042] The present invention has the following advantages and effects compared with the prior art:

[0043] 1. The present invention uses a non-toxic strontium carboxylate catalyst to replace the toxic organotin compound, meeting the environmental protection requirements and can be used as food-contact silicone rubber.

[0044] 2. The present invention uses precipitated silica with an aqueous carrier and a strontium carboxylate catalyst in combination, improving the relatively slow catalytic activity of the Sr catalyst and achieving rapid, uniform, and deep curing of the sealant.

[0045] 3. The present invention synthesizes a special-structured adhesion promoter, containing special active functional groups formed by the ring-opening of active amino groups and epoxy cyclohexane, as well as multi-toothed alkoxy active functional groups. The adhesive has a stable structure, and the different functional groups work together to achieve rapid adhesion to the substrate. At the same time, the multi-toothed alkoxy structure forms a denser cross-linked hydrophobic structure on the substrate surface, making it difficult for water molecules to penetrate the adhesion surface, showing strong water-boiling-resistant adhesion. Meanwhile, the cured colloid has excellent yellowing resistance and is suitable for the rapid adhesion and fixation of the heating plate at the bottom of the electric kettle and the kettle body.

[0046] 4. The strontium-containing catalyst, silane crosslinking agent, and adhesive are placed in different components respectively, improving the storage stability of the components, especially the storage performance of the curing agent component. Components A and B do not crosslink and cure when exposed to air, facilitating sealant preparation and on-site application, and reducing product loss at the same time.

[0047] 5. The mixing ratio of component A and component B is 1:1, which has low requirements for the metering accuracy of equipment, is easy to operate, ensures the stable performance of the silicone sealant after mixing, and is suitable for continuous production in modern industry. Detailed implementation mode

[0048] The present invention will be further described in detail below in conjunction with embodiments, but the implementation modes of the present invention are not limited thereto. The following parts are all by mass.

[0049] Embodiment 1

[0050] 1. Preparation of component A

[0051] (1) Add 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s, 10 parts of hydrophobic fumed silica with a specific surface area of 150 m 2 / g, 2 parts of precipitated silica with a specific surface area of 100 m 2 / g and 8 parts of methyl silicone oil with a viscosity of 100 mPa·s into a dynamic mixer. The revolution speed is 30 Hz, the dispersion speed is 30 Hz, stir for 2 h, and use cooling circulating water to control the temperature not to exceed 80 °C;

[0052] (2) After the above materials are stirred evenly, add 0.5 part of strontium neodecanoate, the revolution rate is 20 Hz, the dispersion speed is 20 Hz, stir for 30 minutes, and control the material temperature not to exceed 40 °C with cooling water during the stirring and dispersion process. Then evacuate, the vacuum degree is -0.08 to -0.1 MPa, stir for 30 minutes, and finally discharge to obtain the finished product of component A, and store it in a sealed manner.

[0053] 2. Preparation of component B

[0054] (1) Add 50 parts of polyalkoxysilyl-terminated polydimethylsiloxane with a viscosity of 1500 mPa·s (Jiangsu Kexing New Materials Co., Ltd., trimethoxy-terminated, commodity model J-15), 50 parts of polyalkoxysilyl-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s (Jiangsu Kexing New Materials Co., Ltd., trimethoxy-terminated, commodity model J-200), 5 parts of methyl silicone oil with a viscosity of 100 mPa·s and 12 parts of hydrophobic fumed silica with a specific surface area of 150 m 2 / g into a dynamic mixer. The revolution speed is 30 Hz, the dispersion speed is 30 Hz, and at the same time heat the materials to 100 - 130 °C, control the vacuum degree to -0.08 to -0.1 MPa, and stir for 2 hours;

[0055] (2) Cool the above materials to below 45°C, add 5 parts of methyltrimethoxysilane and 3 parts of self-made adhesive ①, with a revolution rate of 20 Hz and a dispersion speed of 20 Hz. Control the material temperature not to exceed 45°C with cooling water. At the same time, evacuate to a vacuum degree of -0.08 to -0.1 MPa, stir for 40 minutes, and finally discharge to obtain the finished product of component B, which is stored in a sealed manner.

[0056] 3. Mix the prepared component A and component B in a mass ratio of 1:1. For the performance details of the product, see Table 1.

[0057] The preparation method of the self-made adhesive ① is as follows:

[0058] (1) Under nitrogen protection, add 1 mol (179.3 g) of aminopropyltrimethoxysilane and 2 mol (272.4 g) of methyltrimethoxysilane to a flask. After mixing evenly, heat up to 60 - 70°C, and start to dropwise add 1.2 mol (295.7 g) of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Stir evenly, control the reaction temperature at 60 - 70°C, and finish the dropping within 1 hour.

[0059] (2) After the dropping is completed, keep the reaction at a constant temperature for 1.5 hours, then heat up to 80°C and turn on the vacuum pump. Control the vacuum degree at -0.09 to 0.1 MPa, and heat up to evaporate the generated alcohol and the unreacted end-capping agent methyltrimethoxysilane to obtain the adhesive ①. The structural formula of the adhesive ① is a mixture of A1 and A2, where R1 and R2 are methyl groups, and Y is methyl dimethoxysiloxy.

[0060] Example 2

[0061] 1. Preparation of component A

[0062] (1) Add 20 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 1500 mPa·s, 80 parts of hydroxyl-terminated dimethylsiloxane with a viscosity of 20000 mPa·s, 5 parts of hydrophobic fumed silica with a specific surface area of 300 m 2 / g, and 4 parts of precipitated silica with a specific surface area of 200 m 2 / g to a dynamic mixer. The revolution speed is 35 Hz, the dispersion speed is 35 Hz, stir for 2 h, and control the temperature not to exceed 80°C with cooling circulating water;

[0063] (2) After the above materials are stirred evenly, add 0.5 part of strontium isooctanoate, with a revolution rate of 20 Hz and a dispersion speed of 20 Hz, stir for 30 minutes. During the stirring and dispersion process, control the material temperature not to exceed 40°C with cooling water. Then evacuate to a vacuum degree of -0.08 to -0.1 MPa, stir for 30 minutes, and finally discharge to obtain the finished product of component A, which is stored in a sealed manner.

[0064] 2. Preparation of component B

[0065] (1) Add 100 parts of polyalkoxysilyl-terminated polydimethylsiloxane with a viscosity of 20,000 mPa·s (Jiangsu Kexing New Materials Co., Ltd., product model J-200) and 5 parts of hydrophobic silica with a specific surface area of 300 m 2 / g into a dynamic mixer. The revolution speed is 35 Hz, the dispersion speed is 35 Hz. At the same time, heat the material to 100 - 130 °C, control the vacuum degree at -0.08 to -0.1 MPa, and stir for 2 hours;

[0066] (2) Cool the above material to below 45 °C, add 10 parts of 1,2-bis(trimethoxysilyl)ethane and 5 parts of self-made adhesive ②. The revolution rate is 20 Hz, the dispersion speed is 20 Hz, and use cooling water to control the material temperature not to exceed 45 °C. At the same time, evacuate the air, the vacuum degree is -0.08 to -0.1 MPa, stir for 40 minutes, and finally discharge to obtain the finished product of component B, and store it in a sealed manner.

[0067] 3. Mix the prepared component A and component B in a mass ratio of 1:1. The performance details of the product are shown in Table 1.

[0068] The preparation method of the self-made adhesive ② is as follows:

[0069] (1) Under the protection of nitrogen, add 1 mol (221.4 g) of aminopropyltriethoxysilane and 2 mol (396.6 g) of phenyltrimethoxysilane into a flask, mix them evenly, then heat up to 60 - 70 °C, and start to dropwise add 1.2 mol (346.2 g) of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane. Stir evenly, control the reaction temperature at 60 - 70 °C, and finish dropping in 1.5 hours;

[0070] (2) After dropping, keep the reaction at a constant temperature for 2 hours, then heat up to 90 °C and turn on the vacuum pump, control the vacuum degree at -0.09 to -0.1 MPa, and heat up to distill off the generated alcohol and the unreacted end-capping agent phenyltrimethoxysilane to obtain the adhesive ②. The structural formula is a mixture of A1 and A2, R1 and R2 are ethyl groups, and Y is phenyl dimethoxysiloxy.

[0071] Example 3

[0072] 1. Preparation of component A

[0073] (1) Add 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 1500 mPa·s, 20 parts of hydrophobic silica with a specific surface area of 200 m 2 / g, and 1 part of hydrophobic silica with a specific surface area of 160 m 2Add 14 parts of precipitated silica per gram and 14 parts of methyl silicone oil with a viscosity of 350 mPa·s to a dynamic mixer. The revolution speed is 35 Hz, the dispersion speed is 35 Hz, stir for 2 hours, and use cooling circulating water to control the temperature not to exceed 80 °C.

[0074] (2) After the above materials are stirred evenly, add 1.0 part of strontium neodecanoate, with a revolution rate of 25 Hz and a dispersion speed of 25 Hz, stir for 40 minutes. During the stirring and dispersion process, use cooling water to control the material temperature not to exceed 40 °C. Then evacuate, with a vacuum degree of -0.08 to -0.1 MPa, stir for 30 minutes, and finally discharge to obtain the finished product of component A, and store it in a sealed manner.

[0075] (2) Preparation of component B

[0076] (1) Add 100 parts of poly(dimethylsiloxane) endblocked with polyalkoxysilyl (Jiangsu Kexing New Materials Co., Ltd., endblocked with methyl dimethoxy, commodity model F-10A) with a viscosity of 10000 mPa·s, 10 parts of methyl silicone oil with a viscosity of 50 mPa·s, and 18 parts of hydrophobic precipitated silica with a specific surface area of 100 m 2 / g to a dynamic mixer. The revolution speed is 35 Hz, the dispersion speed is 35 Hz, and at the same time heat the material to 100 - 130 °C, control the vacuum degree to -0.08 to -0.1 MPa, and stir for 2 hours;

[0077] (2) Cool the above materials to below 45 °C, add 1.5 parts of tetraethoxysilane, 1.5 parts of hydrolyzed oligomer of ethyl silicate (Hubei New Blue Sky New Materials Co., Ltd., ethyl silicate 40), and 2 parts of self-made adhesive ③. The revolution rate is 20 Hz, the dispersion speed is 20 Hz, and use cooling water to control the material temperature not to exceed 45 °C. At the same time, evacuate, with a vacuum degree of -0.08 to -0.1 MPa, stir for 40 minutes, and finally discharge to obtain the finished product of component B, and store it in a sealed manner.

[0078] 3. Mix the manufactured components A and B in a mass ratio of 1:1. The performance details of the product are shown in the table.

[0079] The preparation method of the self-made adhesive ③ is as follows:

[0080] (1) Under nitrogen protection, add 1 mol (179.3 g) of aminopropyltrimethoxysilane and 2 mol (272.4 g) of methyltrimethoxysilane to a flask, mix evenly, then heat to 60 - 70 °C, and start to dropwise add 1.5 mol (432.7 g) of 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane. Stir evenly, control the reaction temperature at 60 - 70 °C, and finish dropping in 1 hour;

[0081] (2) After the dropping is completed, keep the reaction at a constant temperature for 2 hours, then raise the temperature to 85 °C and turn on the vacuum pump. Control the vacuum degree to be -0.09 to -0.1 MPa, and raise the temperature to distill off the generated alcohol and the unreacted endblocker methyltrimethoxysilane to obtain the adhesive ③, the structural formula of which is a mixture of A1 and A2, R1 is methyl, R2 is ethyl, and Y is methyl dimethoxysiloxy.

[0082] Example 4

[0083] 1. Preparation of Component A

[0084] (1) Add 100 parts of hydroxyl-terminated polydimethylsiloxane with a viscosity of 10000 mPa·s, 14 parts of hydrophobic fumed silica with a specific surface area of 250 m 2 / g, 2.5 parts of precipitated silica with a specific surface area of 160 m 2 / g, and 10 parts of methyl silicone oil with a viscosity of 1000 mPa·s into a dynamic mixer. The revolution speed is 35 Hz, the dispersion speed is 35 Hz, stir for 2 h, and use cooling circulating water to control the temperature not to exceed 80 °C;

[0085] (2) After the above materials are stirred evenly, add 0.2 parts of strontium isooctanoate, the revolution rate is 25 Hz, the dispersion speed is 25 Hz, stir for 30 minutes, and use cooling water to control the material temperature not to exceed 40 °C during the stirring and dispersion process. Then evacuate, the vacuum degree is -0.08 to -0.1 MPa, stir for 30 minutes, and finally discharge to obtain the finished product of Component A, and store it in a sealed manner.

[0086] 2. Preparation of Component B

[0087] (1) Add 100 parts of polyalkoxysilyl-terminated polydimethylsiloxane with a viscosity of 20000 mPa·s (Jiangsu Kexing New Materials Co., Ltd., product model J-200), 8 parts of methyl silicone oil with a viscosity of 1000 mPa·s, and 16 parts of hydrophobic fumed silica with a specific surface area of 150 m 2 / g into a dynamic mixer. The revolution speed is 35 Hz, the dispersion speed is 35 Hz, and at the same time heat the material to 100 - 130 °C, control the vacuum degree to be -0.08 to -0.1 MPa, and stir for 2 hours;

[0088] (2) Cool the above materials to below 45 °C, add 2.0 parts of methyltrimethoxysilane, 2.0 parts of polymethyltriethoxysilane and 3 parts of self-made adhesive ④, the revolution rate is 20 Hz, the dispersion speed is 20 Hz, and use cooling water to control the material temperature not to exceed 45 °C. At the same time, evacuate, the vacuum degree is -0.08 to -0.1 MPa, stir for 40 minutes, and finally discharge to obtain the finished product of Component B, and store it in a sealed manner.

[0089] 3. Mix the manufactured Component A and Component B in a mass ratio of 1:1. For the performance details of the product, see the table.

[0090] The preparation method of the self-made adhesive ④ is as follows:

[0091] (1) Under nitrogen protection, add 1 mol (221.4 g) of aminopropyltriethoxysilane and 2 mol (396.6 g) of phenyltrimethoxysilane to the flask, mix them evenly, then heat up to 60 - 70 °C, and start to dropwise add 1.0 mol (246.4 g) of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Stir evenly, control the reaction temperature at 60 - 70 °C, and finish dropping within 1 hour.

[0092] (2) After dropping, keep the reaction at a constant temperature for 1.5 hours, then heat up to 85 °C, turn on the vacuum pump, control the vacuum degree at -0.09 to 0.1 MPa, and heat up to evaporate the generated methanol and the unreacted capping agent phenyltrimethoxysilane to obtain the adhesive ④, whose structural formula is A1, where R1 is ethyl, R2 is methyl, and Y is phenyldimethoxysiloxy.

[0093] Comparative Example 1

[0094] Compared with Example 1, in this comparative example, 2 parts of hydrophobic silica with a specific surface area of 100 m 2 / g is used in Component A to replace 2 parts of precipitated silica with the same specific surface area. The other components and the preparation process are the same as those in Example 1. Mix the manufactured Component A and Component B in a mass ratio of 1:1. For the performance details of the product, see Table 1.

[0095] Comparative Example 2

[0096] Compared with Example 1, in this comparative example, 3 parts of aminopropyltrimethoxysilane are used in Component A to replace 3 parts of the self-made adhesive ①. The other components and the preparation process are the same as those in Example 1. Mix the manufactured Component A and Component B in a mass ratio of 1:1. For the performance details of the product, see Table 1.

[0097] Comparative Example 3

[0098] Compared with Example 1, in this comparative example, 3 parts of the commercially available adhesive JH-OP8711 (Hubei Jianghan New Materials Co., Ltd., epoxy-modified amino silane) are used in Component A to replace 3 parts of the self-made adhesive ①. The other components and the preparation process are the same as those in Example 1. Mix the manufactured Component A and Component B in a mass ratio of 1:1.

[0099] Comparative Example 4

[0100] Compared with Example 1, in this comparative example, 3 parts of self-made adhesive B are added to component A to replace self-made adhesive ①. Compared with the adhesive of the present invention, a capping agent is not used. The other components and the preparation process are the same as those in Example 1. The manufactured component A and component B are mixed in a mass ratio of 1:1, and the product performance is shown in the table.

[0101] The preparation method of self-made adhesive B is as follows:

[0102] (1) Under nitrogen protection, add 1 mol (179.3 g) of aminopropyltrimethoxysilane to a flask, heat up to 60 - 70 °C, and start dropping 1.2 mol (295.7 g) of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Stir evenly, control the reaction temperature at 60 - 70 °C, and finish dropping in 1 hour.

[0103] (2) After dropping, keep the reaction at a constant temperature for 1.5 hours, then heat up to 80 °C and turn on the vacuum pump. Control the vacuum degree at -0.09 to 0.1 MPa, and heat up to evaporate the generated methanol to obtain the adhesive B, which is a mixture of the following two structures:

[0104]

[0105]

[0106] Performance test method:

[0107] Adhesive substrate: The stainless steel heating plate substrate provided by the electric kettle manufacturer.

[0108] Surface dry test method: GB / T 13477.5.

[0109] Hardness test method: GB / T531.

[0110] Initial solidification time test method: Extrude the two-component glue on a clean substrate to make the glue width about 15 mm and the glue thickness about 10 mm. Cure for a certain time, cut the glue strip to observe whether there is liquid inside the glue strip. If there is no liquid inside the whole glue strip, the dry time is determined as the initial solidification time.

[0111] Adhesion test method:

[0112] Adhesive substrate: The stainless steel heating plate substrate provided by the manufacturer.

[0113] Adhesion onset time: Extrude the two-component glue on a clean substrate to make the glue width about 15 mm, the glue thickness about 5 mm, and the glue length about 5 cm. Cure at room temperature of 25 ± 5 °C and humidity of 55 ± 5%. After curing for a certain time, tear the glue layer. When the adhesion between the glue and the substrate reaches cohesive failure, it is judged as the adhesion onset time.

[0114] Water-boiling resistance adhesion: Extrude two-component glue on a clean substrate, making the glue width about 15 mm, glue thickness about 5 mm, and glue length about 5 cm. Cure it for 7 days at room temperature of 25 ± 5 °C and humidity of 55 ± 5%. Then put it into a 100 °C water bath, boil for 168 hours and take it out. When the adhered substrate cools down to room temperature, tear off the glue layer and calculate the remaining area on the substrate.

[0115] Yellowing resistance test: Apply glue to make the glue thickness about 5 mm, glue length about 5 cm, and glue width about 5 cm. Cure it for 7 days at room temperature of 25 ± 5 °C and humidity of 55 ± 5%. Then put it into an oven at 150 °C and bake for 48 hr, and observe the yellowing situation of the glue strip.

[0116] Table 1 Silicone Performance Test

[0117]

[0118]

[0119] Note: C + number indicates the remaining silicone area on the substrate when the silicone adhesion shows cohesive failure.

[0120] Four adhesives self-made in the present invention and adhesive B are stored in sealed condition at room temperature to investigate the influence of storage time on the stability of the adhesives.

[0121] Table 2 Adhesive Storage Performance Test

[0122]

[0123] It can be seen from the data in Table 1 that the equal-proportion two-component alcohol-free silicone sealant for electric kettles in Examples 1 - 4 of the present invention uses a non-toxic and environmentally friendly strontium catalyst in combination with deep-curing agent precipitated silica, achieving the following effects: The catalyst is non-toxic and environmentally friendly, and the room-temperature curing speed is fast. During the synthesis process of the adhesive in the present invention, the primary amino group in the reaction product active amino silane is transformed into secondary amino group and tertiary amino group, without active hydrogen atoms, and the formed silicone has good yellowing resistance. The hydroxyl group formed by the ring-opening reaction of active amino silane and epoxy cyclohexane is capped by methyltrimethoxysilane or phenyltrimethoxysilane, the product structure is stable, and the multi-toothed alkoxy structure formed by the adhesive after capping helps to improve the water-boiling resistance adhesion of the sealant. The introduction of cyclohexane improves the hydrophobicity of the adhesive, and the special structure formed by the ring-opening reaction of active amino silane and epoxy cyclohexane promotes adhesion and improves the water-boiling resistance adhesion of the adhesive. Using the adhesive of the present invention, the following effects are achieved: The adhesive has good storage stability, the silicone has good yellowing resistance effect, and the retention rate of water-boiling resistance adhesion is high.

[0124] The initial curing time and adhesion onset time of Comparative Example 1 are significantly worse than those of Example 1, because the precipitated silica prepared by the deep-curing agent is lacking in the formula. This shows that the precipitated silica added in the present invention effectively promotes the curing speed of the sealant.

[0125] Comparative Example 2 uses the conventional adhesion coupling agent aminopropyltrimethoxysilane, which contains primary amino groups, resulting in poor thermal aging performance of the silica gel and easy yellowing. At the same time, the adhesive has good hydrophilicity, resulting in the adhesive layer formed between the silica gel and the substrate being damaged by water vapor, adhesive peeling off, and poor adhesion performance resistant to boiling water.

[0126] Comparative Example 3 uses the commercially available adhesive JH-OP8711. Compared with Comparative Example 3, the adhesion performance resistant to boiling water is improved, and at the same time, the yellowing resistance of the silica gel is improved. However, compared with the adhesive of the present invention, the hydrophobicity of the adhesive is still relatively weak, and the retention rate of the adhesion performance resistant to boiling water is relatively low.

[0127] Comparative Example 4 uses the adhesive B formed by the ring-opening of active amino silane and epoxycyclohexane silane. Compared with Comparative Example 3, Comparative Example 4 improves the yellowing resistance and the adhesion performance resistant to boiling water of the silica gel. It can be seen from the data in Table 2 that compared with the adhesive of the present invention, due to the lack of a capping agent in the synthesis process, the storage stability is poor: after being placed for 3 months, the viscosity increases significantly, and after being placed for 1 year, the adhesive has lost its practical value. Compared with Example 1 of the present invention, the adhesive lacks a multi-toothed alkoxy structure, and the adhesion performance resistant to boiling water is still relatively weak.

[0128] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. An equal-proportion translucent two-component dealcoholized silicone sealant for an electric kettle, characterized in that: It includes component A and component B; Component A includes the following components by mass: 100 parts of terminal hydroxyl polydimethylsiloxane, 5 to 20 parts of reinforcing filler, 1 to 4 parts of curing accelerator, 0 to 14 parts of plasticizer, and 0.2 to 1.0 parts of catalyst; Component B includes the following components in parts by mass: 100 parts of polyalkoxysilyl-terminated polydimethylsiloxane, 5 to 18 parts of reinforcing filler, 0 to 10 parts of plasticizer, 3 to 10 parts of crosslinking agent, and 2 to 5 parts of adhesive; The adhesive is at least one of an adhesive having a structural formula as shown in A1 and an adhesive having a structural formula as shown in A2; Wherein, R1 and R2 are CH3 or C2H5, and R1 and R2 are the same or different; Y is 2. The equal-proportion translucent two-component dealcoholized silicone sealant for electric kettle according to claim 1, characterized in that: The terminal hydroxyl polydimethylsiloxane is a terminal hydroxyl polydimethylsiloxane having a viscosity of 750 to 30000 mPa·S at 25°C; The polyalkoxysilyl-terminated polydimethylsiloxane is a polyalkoxysilyl-terminated polydimethylsiloxane having a viscosity of 750 to 30000 mPa·S at 25°C.

3. The equal-proportion translucent two-component dealcoholized silicone sealant for electric kettle according to claim 1, characterized in that: The reinforcing filler is at least one of fumed silica and hydrophobic silica; The catalyst is a carboxylate containing strontium; The curing accelerator is precipitated silica.

4. The equal-proportion translucent two-component dealcoholized silicone sealant for an electric kettle according to claim 3, characterized in that: The hydrophobic white carbon black has a specific surface area of ​​100 to 300 m 2 / g of hydrophobic silica; The strontium-containing carboxylate is at least one of strontium isooctanoate and strontium neodecanoate; The precipitated silica has a specific surface area of ​​100 to 200 m 2 / g of precipitated silica.

5. The equal-proportion translucent two-component dealcoholized silicone sealant for electric kettle according to claim 1, characterized in that: The plasticizer is dimethyl silicone oil; The crosslinking agent is at least one of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, ethyl silicate hydrolyzed oligomer, methyltrimethoxysilane, methyltriethoxysilane, polymethyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, polymethyltriethoxysilane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(methyldimethoxysilyl)ethane and 1,2-bis(methyldiethoxysilyl)ethane.

6. The equal-proportion translucent two-component dealcoholized silicone sealant for electric kettle according to claim 1, characterized in that: The adhesive is prepared by the following steps: (1) Under the protection of inert gas, after the aminosilane and the silane capping agent are evenly mixed, the temperature is raised to 60-70° C., and epoxy cyclohexyl silane is added dropwise, and the reaction temperature is controlled at 60-70° C. and the addition time is controlled within 1-2 hours; (2) After the addition is complete, the reaction is carried out by keeping the temperature for 1 to 2 hours, then the temperature is raised to 80 to 90° C., a vacuum pump is turned on, and the vacuum degree is controlled to be -0.09 to -0.1 MPa to remove the generated alcohol and the unreacted silane capping agent to obtain an adhesive; The silane capping agent is at least one of methyltrimethoxysilane and phenyltrimethoxysilane; The aminosilane is at least one of aminopropyltrimethoxysilane and aminopropyltriethoxysilane; The epoxycyclohexylsilane is at least one of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane; The aminosilane and the silane capping agent are mixed in a molar ratio of 1:2; The aminosilane and the epoxycyclohexylsilane are matched in a molar ratio of 1:1 to 1:1.

5.

7. The method for preparing the equal-proportion translucent two-component dealcoholized organosilicon sealant for electric kettles according to any one of claims 1 to 6, characterized in that The steps include: (1) Preparation of component A: ①Use a power mixer to mix the terminal hydroxyl polydimethylsiloxane, reinforcing filler, curing accelerator and plasticizer evenly, with a revolution speed of 20 to 40 Hz and a dispersion speed of 20 to 40 Hz, and then control the material temperature not to exceed 80°C and stir for 1 to 2 hours; ② The material finally obtained in step ① is cooled to below 45°C, and then a catalyst is added, the revolution speed is 10-30Hz, the dispersion speed is 10-30Hz, and the stirring is carried out for 20-40min, and the material temperature is controlled not to exceed 40°C with cooling water, and then the stirring is continued for 10-30min for degassing under vacuum conditions, and the vacuum degree is -0.08-0.10MPa, and finally the material is discharged to obtain component A, which is sealed and stored; (2) Preparation of component B: ①Use a power mixer to mix the polyalkoxysilane-terminated polydimethylsiloxane and reinforcing filler evenly, with an orbital speed of 20 to 40 Hz and a dispersion speed of 20 to 40 Hz. Heat the materials to 100 to 130°C and stir at a vacuum degree of -0.08 to -0.10 MPa for 1 to 2 hours. ② The material finally obtained in step ① is cooled to below 45°C, a plasticizer is added, the revolution speed is 10 to 30HZ, the dispersion speed is 10 to 30HZ, and the stirring is carried out for 20 to 40min; then a crosslinking agent and an adhesive are added in sequence, the revolution speed is 10 to 30HZ, the dispersion speed is 10 to 30HZ, and the material temperature is controlled not to exceed 40°C with cooling water, and a vacuum is drawn at the same time, the vacuum degree is -0.08 to -0.10MPa, and the stirring is carried out for 30 to 60min. Finally, the material is discharged to obtain component B, and the material is sealed for storage.

8. Use of the equal-ratio translucent two-component dealcoholized organosilicon sealant for electric kettles according to any one of claims 1 to 6 in the preparation of electric kettles.

9. The use according to claim 8, characterized in that The method comprises the following steps: mixing component A and component B in an equal mass ratio or an equal volume ratio of 1:1.

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