Dual-curing single-component high-temperature-resistant glue and preparation method thereof

Abstract

The invention provides a dual-curing single-component high-temperature-resistant adhesive and a preparation method thereof. The high-temperature-resistant glue comprises hydroxyl oxazolidine modified hydrogen-containing silicone oil, hydroxyl-containing MQ silicon resin, a filler, a surface treating agent, an adhesion promoter, blocked aromatic isocyanate and a melamine-containing compound. The adhesive contains a large number of high-temperature-resistant structures and strong bonding structures, and meets the requirement for long-time high-temperature-resistant work of the PTC assembly. The dual-curing mode of combining moisture curing and thermocuring not only ensures the requirement of high production efficiency of the quickly assembled PTC component, but also avoids the defect of weak bonding force of a single-component thermocuring addition type high-temperature-resistant adhesive.

Description

Technical Field

[0001] The invention belongs to the field of organic silicone adhesives, and specifically relates to a dual-curing single-component high-temperature resistant adhesive and a preparation method thereof. Background Art

[0002] PTC material is a semiconductor ceramic material based on BaTiO3. The highest temperature of industrialized PTC heating materials has reached 300℃.

[0003] PTC ceramic heater is a highly efficient heater with uniform heat distribution and a metal alloy with excellent thermal conductivity, which ensures uniform temperature of the hot surface and eliminates hot spots and cold spots of the equipment. It is a compact, small, easy to install and durable heating device made of PTC ceramic thermistor as the heating element and bonded with corrugated aluminum strips by high-temperature adhesive. It is suitable for electric heating products such as electric straight hair clips, curling irons, electric irons, electric soldering irons, hair dryers, dryers, water steamers, heaters, toilet warm water toilet seats, medical equipment, etc. Ceramic heaters have the advantages of easy installation, high temperature resistance, fast heat transfer, good insulation, and manufacturing without restrictions on models and specifications.

[0004] The high temperature resistant adhesive used in PTC ceramic heaters is organic silicone adhesive. This is because organic silicone contains high bond energy Si-O bonds, and the bonds have the characteristics of partial ionic bonds, which give organic silicone heat resistance, high strength and antioxidant properties. Although organic silicone materials have the advantage of good heat resistance, they have the disadvantages of poor mechanical properties and weak adhesion. Therefore, silicone rubber still has deficiencies in high temperature resistance and mechanical properties. Under long-term high temperature conditions, there is a significant decay, which leads to the attenuation of the life of the PTC heater.

[0005] At present, there are three main methods to improve the heat resistance of silicone rubber: 1. By changing the structure of the side groups of silicone rubber molecules, such as introducing phenyl groups, etc., to inhibit the cross-linking and degradation reactions caused by the oxidative decomposition of the organic side groups of silicone rubber; 2. By introducing large-volume segments such as carbon decaborane groups into the main chain of silicone rubber molecules to prevent the degradation of the main chain of silicone rubber caused by oxidative depolymerization; 3. By adding heat-resistant additives such as ferric oxide and rare earth elements to inhibit the side chain cross-linking of silicone rubber. Among them, adding heat-resistant fillers to silicone rubber is the most effective, economical, convenient and quick solution.

[0006] At present, the commonly used silicone high temperature resistant adhesives on the market are single-component addition adhesives and room temperature curing condensation adhesives, but both have some disadvantages. Ordinary addition adhesives have poor heat resistance, and due to the limitations of the adhesive force of the colloid, the overall sealing and waterproof performance of the components is poor. In addition, there are disadvantages such as short shelf life, easy sedimentation, easy to generate bubbles during curing, and large equipment investment.

[0007] However, room temperature curing single-component high temperature resistant adhesive can only be used for a long time at 180-200℃. When the temperature exceeds 200℃, the Si-O bond in the organic polysilane is easy to break, and the hardness of the silicone rubber will increase, cracking and losing elasticity, which is worthless. However, in the application of PTC heater component bonding, there are very high requirements for the high temperature resistance of silicone, usually requiring more than 250℃ and more than 1000 hours. In addition, the single-component moisture-curing adhesive has a long curing time under room temperature moisture curing conditions and low production efficiency. PTC heaters have relatively high requirements for production efficiency and bonding strength, which is also the reason why single-component room temperature moisture-curing products are rarely used. Summary of the invention

[0008] In view of the above-mentioned problems existing in the prior art, one of the objects of the present invention is to provide a dual-curing one-component high-temperature resistant adhesive. The modified adhesive has good high-temperature resistance and excellent mechanical properties. It adopts dual curing methods of moisture curing and heat curing, has high curing efficiency, requires less equipment investment, and has excellent storage stability.

[0009] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solution:

[0010] A dual-curing single-component high-temperature resistant adhesive, the high-temperature resistant adhesive comprising the following components:

[0011]

[0012] The compound obtained by modifying the hydroxyoxazolidine compound with hydrogen-containing silicone oil in the present invention reacts with water first during the wet curing process of the adhesive because its activity in reacting with water is much higher than that in reacting with isocyanate with water, thereby avoiding the possibility of generating carbon dioxide by the reaction of isocyanate with water, avoiding bubbles in the adhesive and surface defects such as pinholes and erosion. The compound obtained by modifying the hydroxyoxazolidine compound with hydrogen-containing silicone oil has a macromolecular structure, which not only plays the role of a dehydrating agent and improves storage stability, but also accelerates the curing reaction speed.

[0013] At the same time, the oxazolidinyl group in the present invention undergoes a ring-opening reaction to generate NH and OH groups during the reaction with water. The formed NH groups react with the NCO groups of isocyanate to form a cross-linked three-dimensional network, which improves the defect of poor mechanical strength of traditional organic silicone adhesives. The compound obtained after the hydroxy oxazolidinyl compound is modified with hydrogen-containing silicone oil plays the role of a cross-linking agent. The carbamate bond formed by it and isocyanate can form a strong bonding force with the substrate and has good bonding force. After the colloid is cured, it contains a large number of rigid groups such as benzene rings, carbamate bonds, urea bonds, etc., which promote the tensile strength of 4.0 to 6.0 MPa; and its chemical bonds have strong adhesion to the substrate, and the shear strength is 3.0 to 5.0 MPa. The bonding strength of the colloid can meet the requirements of component bonding and sealing.

[0014] The invention introduces a blocked isocyanate curing agent and a hydroxyl-containing melamine compound, releases aromatic isocyanate and a blocking agent under heating conditions, and the aromatic isocyanate undergoes a cross-linking reaction with a hydroxyl-containing MQ resin and a hydroxyl-containing melamine compound. When the temperature is further increased, a CN bond in a reaction product of the aromatic isocyanate and the hydroxyl-containing melamine compound is first broken, and the generated melamine is further condensed to form an insoluble and infusible structure, thereby achieving the purpose of dual heat curing; the mechanical strength after curing is rapidly improved, and the component is shaped; the heat curing reaction is completed within 30 to 60 minutes, and the properties such as bonding strength and tensile strength are improved; the system has both heat curing and moisture curing, and greatly improves the curing speed and bonding strength of single-component moisture curing.

[0015] In one embodiment of the present invention, the hydroxyoxazolidine-modified hydrogenated silicone oil is prepared by dehydrogenation of hydrogenated silicone oil and a hydroxyoxazolidine compound; preferably, the hydrogenated silicone oil is one or more of end-side hydrogenated silicone oil, side hydrogenated silicone oil, end hydrogenated silicone oil, and single-end hydrogenated silicone oil; preferably, the hydroxyoxazolidine compound is a dehydration product of the reaction of diethanolamine and an aldehyde compound; preferably, in the dehydrogenation preparation, the hydrogenated silicone oil is 5 to 30 parts, preferably 10 to 25 parts, and the hydroxyoxazolidine compound is 0.1 to 5 parts, preferably 1 to 3 parts.

[0016] In one embodiment of the present invention, a dehydrogenation catalyst may be added during the dehydrogenation preparation; preferably, the dehydrogenation catalyst is an organic tin catalyst, preferably one or more of dibutyltin diisooctanoate, stannous octoate, dibutyltin diisooctanoate, dibutyltin diacetate, dibutyltin didodecylsulfide, and dioctyltin mercaptan; preferably, the amount of the dehydrogenation catalyst added is 0.05 to 1 part, preferably 0.1 to 0.5 part. It is well known in the art that the above catalysts are commonly used catalysts for dehydrogenation reactions.

[0017] In one embodiment of the present invention, the hydroxyl-containing MQ resin is a co-hydrolyzate of tetraalkoxysilane (Q unit) and trimethylethoxysilane (M unit); preferably, the co-hydrolyzate has an M / Q value of 0.60-0.80, a molecular weight of 5000-20,000, and a hydroxyl content of 1.0-6.0 wt%.

[0018] In one embodiment of the present invention, the filler is one or more of nitrides, oxides, and carbides, preferably one or more of aluminum oxide, zinc oxide, cerium oxide, silicon carbide, boron nitride, aluminum nitride, and iron oxide.

[0019] In one embodiment of the present invention, the surface treatment agent is one or more of silane compounds, preferably one or more of vinyltrioxymethylsilane, hexamethyldisilazane, hexamethyldisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, and stearic acid.

[0020] In one embodiment of the present invention, black paste is optionally added, and the black paste is a mixture of one or more of carbon, silicon, iron and silicone oil, preferably a mixture of carbon black and dimethyl silicone oil. It is well known in the art that the above black paste is a commonly used black paste for adhesives. Preferably, the amount of black paste is 0.1 to 1 part, preferably 0.2 to 0.8 parts.

[0021] In one embodiment of the present invention, the adhesion promoter is one or more of an epoxy silane coupling agent, an amino silane coupling agent, and a mercapto silane coupling agent; preferably 3-glycidyloxypropyl triethoxysilane, 3-glycidyloxypropyl trimethoxysilane (KH560), 3-glycidyloxypropyl methyl dimethoxysilane, 3-glycidyloxypropyl methyl diethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane, One or more of 2-(4-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropyltriethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropyltri ...ethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropyltriethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropyltriethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropyltriethoxysilane, 2-(4-(2-aminoethyl)-3-aminopropyltrieth

[0022] In one embodiment of the present invention, an antioxidant is optionally added, and the antioxidant is an aromatic amine antioxidant and / or a phenolic antioxidant, preferably one or more of tea polyphenols (TP), tocopherol, flavonoids, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ). It is well known in the art that the above antioxidants are commonly used antioxidants for adhesives. Preferably, the amount of the antioxidant is 1 to 5 parts, preferably 1 to 3 parts.

[0023] In one embodiment of the present invention, a titanate catalyst is optionally added for the convenience of downstream use. The titanate catalyst is a complex of a titanate compound and a ligand, preferably one or more of 2-ethylhexyl titanate, diisopropoxy titanium bis(ethyl acetoacetate) complex (T726), 1,3-propylenedioxy titanium bis(ethyl acetoacetate) complex (T9000), monoalkoxy titanate, polyalkoxy titanate, dialkoxy titanium bis(β-diketone ester) complex, and titanate diol ester β-diketone complex.

[0024] In one embodiment of the present invention, an organic tin catalyst is optionally contained for downstream use, and the organic tin catalyst is preferably one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diisooctoate, dibutyltin diacetate, dibutyltin didodecylsulfide, and dioctyltin mercaptan.

[0025] In one embodiment of the present invention, the addition amount of the above titanate and / or organotin catalyst is 0.1 to 5 parts, preferably 1 to 3 parts.

[0026] In one embodiment of the present invention, the blocked aromatic isocyanate comprises one or more of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, methoxyphenyl-2,4-diisocyanate, polymethylene polyphenyl isocyanate, 3,3′-dimethoxy-4,4′-biphenyl diisocyanate, toluene-2,4,6-triisocyanate, toluene diisocyanate-trimethylolpropane, and TDI trimer, which are blocked with phenol and / or caprolactam.

[0027] In one embodiment of the present invention, the hydroxyl-containing melamine compound is one or more of monomethylolmelamine, dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine and hexamethylolmelamine.

[0028] Another object of the present invention is to provide a method for preparing high temperature resistant adhesive.

[0029] A method for preparing the above-mentioned high temperature resistant adhesive, the preparation method comprising the following steps:

[0030] S1: The hydrogen-containing silicone oil reacts with the hydroxyoxazolidine compound to remove hydrogen;

[0031] S2: adding hydroxyl-containing MQ silicone resin and filler to the modified silicone oil, mixing evenly, adding surface treatment agent for treatment, and cooling;

[0032] S3: adding an adhesion promoter, a blocked aromatic isocyanate, and a melamine-containing compound to the above-mentioned base adhesive, and mixing and stirring;

[0033] S4: Add titanate and / or organotin catalyst, mix and stir, and pack into high temperature resistant rubber products.

[0034] In one embodiment of the present invention, the S1 reaction time is 1-3 hours and the reaction temperature is 20-40°C.

[0035] In one embodiment of the present invention, the S2 is treated at 60-180°C and cooled to below 40°C.

[0036] In one embodiment of the present invention, the material temperature is controlled to be less than 40° C. during the stirring in S4.

[0037] Another object of the present invention is to provide a use of high temperature resistant glue.

[0038] A use of a high temperature resistant adhesive, wherein the high temperature resistant adhesive is the above-mentioned high temperature resistant adhesive, or is the high temperature resistant adhesive prepared by the above-mentioned preparation method, and the high temperature resistant adhesive is used in the bonding field for long-term use under high temperature conditions, preferably in the bonding field of PTC ceramic heaters.

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

[0040] (1) The product prepared by this method has excellent high temperature resistance. Its temperature resistance can reach 300°C, which meets the requirements of continuous operation of components under high temperature conditions. After aging at 300°C for 3000h, the colloid basically has no cracking or falling off. The colloid has good temperature resistance and can remain without cracking or falling off under long-term high temperature. It has good high temperature resistance and good adhesion, which increases the development space of room temperature curing silicone adhesives.

[0041] (2) The compound obtained by modifying the hydroxyoxazolidine compound with hydrogen-containing silicone oil avoids the formation of bubbles in the adhesive and the appearance of surface defects such as pinholes and fogging during the wet curing process of the adhesive. The compound not only acts as a dehydrating agent and improves the storage stability, but also accelerates the curing reaction speed. At the same time, it has good storage stability. If stored in a cool, dry and ventilated environment at room temperature below 28°C, it can be stored for 12 months, which is much better than the shelf life of 6 months of addition-type heat-curing high-temperature resistant adhesive stored at -5°C, and overcomes the shortcoming of the short shelf life of the single-component addition type.

[0042] (3) Improved the defect of poor mechanical strength of traditional organic silicone adhesive. It has good bonding strength. After the colloid is cured, it contains a large number of rigid groups such as benzene rings, carbamate bonds, urea bonds, etc., which promote the tensile strength of 4.0-6.0MPa; and its chemical bond has strong adhesion to the substrate, with a shear strength of 3.0-5.0MPa. The bonding strength of the colloid can meet the requirements of component bonding and sealing.

[0043] (4) The dual curing method is carried out in two stages. The heat curing stage can quickly fix the system, and the wet curing stage enhances the bonding strength. The colloid cures very quickly under heating conditions, which can meet the needs of assembly line production operations. The curing time is 30 to 60 minutes. The deep layer can be completely cured by wet curing, overcoming the disadvantage of slow wet curing alone. It breaks through the disadvantage of slow curing of silicone one-component wet curing adhesives and sealants, and has a fast curing performance similar to addition-type heat-curing products or two-component wet curing products. DETAILED DESCRIPTION

[0044] The present invention is further described below in conjunction with the examples. The sources of some of the main raw materials are shown in Table 1.

[0045]

[0046]

[0047] Example 1

[0048] 1 g of dibutyltin dilaurate was added to 100 g of hydrogen-terminated polydimethylmethylhydrogensiloxane RH-LHC-3, and stirred for 10 min at a speed of 500 rpm / min. 11 g of hydroxyoxazolidine compound Incozol 3 was added dropwise to the above solution. The reaction time was 1 h and the reaction temperature was 40°C.

[0049] Add 50g of hydroxyl-containing MQ resin (molecular weight 20,000) to the above solution, stir for 10min at a speed of 500rpm / min, add 345g of aluminum oxide BAK-20, 50g of cerium oxide and 250g of zinc oxide FB-72F in three times, stir for 5min each time a batch of powder is added, and the speed is 100rpm / min; after fully mixing, add 5g of vinyltrimethoxysilane and 7g of black slurry, treat at 65℃ for 2h, and cool to 35℃.

[0050] 100g of blocked aromatic isocyanate Desmodur BL1100, 40g of silane coupling agent KH560, 16g of antioxidant 1010 and 10g of tetramethylol melamine were added to the above-mentioned base rubber in sequence, and mixed and stirred for 0.5h under vacuum conditions at a stirring speed of 50rpm / min and the vacuum degree was maintained at -0.09Mpa.

[0051] Under nitrogen protection, 15 g of dibutyltin dilaurate was added and the mixture was stirred for 20 min at a stirring speed of 100 rpm / min. During the stirring, the material temperature was controlled to 30° C.

[0052] In an airtight condition, the rubber material is packaged and pressed from the kettle into the rubber hose using a press and stored at room temperature.

[0053] Example 2

[0054] Add 5g of stannous octoate to 190g of polydimethylmethylhydrogensiloxane RH-H502, stir for 10min at a speed of 500rpm / min, add 25g of 3-(2-hydroxyethyl)-2-oxazolidinone dropwise to the above solution, react for 1h at a reaction temperature of 30°C.

[0055] Add 90g of hydroxyl-containing MQ resin (molecular weight 10000) to the above solution, stir for 30min at a speed of 700rpm / min, add 345g of aluminum oxide silicon carbide, 50g of iron oxide and 132.5g of zinc oxide FB-72F in three times, stir for 5min each time a batch of powder is added, and the speed is 100rpm / min; after fully mixing, add 1.5g of hexamethylsilazane and 5g of black slurry, treat at 170℃ for 2h, and cool to 40℃.

[0056] 51g of blocked aromatic isocyanate Desmodur RL1265, 30g of silane coupling agent KH570, 22g of antioxidant 1035 and 27g of pentahydroxymethyl melamine were added to the above-mentioned base rubber in sequence, and mixed and stirred for 0.5h under vacuum conditions at a stirring speed of 200rpm / min and the vacuum degree was maintained at -0.09Mpa.

[0057] Under nitrogen protection, 26 g of stannous octoate was added and the mixture was stirred for 20 minutes at a stirring speed of 100 rpm / min. The material temperature was controlled at 30° C. during stirring.

[0058] In an airtight condition, the rubber material is packaged and pressed from the kettle into the rubber hose using a press and stored at room temperature.

[0059] Example 3

[0060] 3 g of dibutyltin diisooctanoate was added to 155 g of hydrogen-terminated polydimethylsiloxane RH-H518, and stirred for 10 min at a speed of 500 rpm / min. 20.1 g of 3-hydroxyisoxazole was added dropwise to the above solution. The reaction time was 2 h and the reaction temperature was 20°C.

[0061] Add 148g of hydroxyl-containing MQ resin (molecular weight 5000) to the above solution, stir for 10min at a speed of 500rpm / min, add 345g of boron nitride, 50g of cerium oxide and 97g of aluminum nitride in three times, stir for 5min each time a batch of powder is added, and the speed is 100rpm / min; after fully mixing, add 2.9g of stearic acid and 2g of black slurry, treat at 110℃ for 2h, and cool to 25℃.

[0062] 76g of blocked aromatic isocyanate Desmodur CT, 21g of silane coupling agent KH540, 29g of antioxidant 168 and 39g of hexahydroxymethyl melamine were added to the above-mentioned base rubber in sequence, and mixed and stirred for 0.5h under vacuum conditions at a stirring speed of 100rpm / min and the vacuum degree was maintained at -0.09Mpa.

[0063] Under nitrogen protection, 12 g of 1,3-propanedioxytitanium bis(ethyl acetoacetate) complex (T9000) was added and mixed and stirred for 20 minutes at a stirring speed of 100 rpm / min. The material temperature was controlled at 25° C. during stirring.

[0064] Comparative Example 1

[0065] Compared with Example 1, glycerol was used to replace the hydroxyoxazolidine compound Incozol 3. The obtained modified hydrogenated silicone oil has no dehydrating agent effect.

[0066] Add 1g of dibutyltin dilaurate to 100g of hydrogen-terminated polydimethylmethylhydrogensiloxane RH-LHC-3, stir for 10min at a speed of 500rpm / min, add 11g of propylene glycol dropwise to the above solution, react for 1h, and the reaction temperature is 40°C.

[0067] Add 50g of hydroxyl-containing MQ resin (molecular weight 20,000) to the above solution, stir for 10min at a speed of 500rpm / min, add 345g of aluminum oxide BAK-20, 50g of cerium oxide and 250g of zinc oxide FB-72F in three times, stir for 5min each time a batch of powder is added, and the speed is 100rpm / min; after fully mixing, add 5g of vinyltrimethoxysilane and 7g of black slurry, treat at 65℃ for 2h, and cool to 35℃.

[0068] 100g of blocked aromatic isocyanate Desmodur BL1100, 40g of silane coupling agent KH560, 16g of antioxidant 1010 and 10g of tetramethylol melamine were added to the above-mentioned base rubber in sequence, and mixed and stirred for 0.5h under vacuum conditions at a stirring speed of 50rpm / min and the vacuum degree was maintained at -0.09Mpa.

[0069] Under nitrogen protection, 15 g of dibutyltin dilaurate was added and the mixture was stirred for 20 min at a stirring speed of 100 rpm / min. During the stirring, the material temperature was controlled to 30° C.

[0070] In an airtight condition, the rubber material is packaged and pressed from the kettle into the rubber hose using a press and stored at room temperature.

[0071] Comparative Example 2

[0072] Compared with Example 2, TDI was used to replace the blocked aromatic isocyanate Desmodur RL1265. TDI does not have the thermal decomposition characteristics of the blocked aromatic isocyanate Desmodur RL1265, and the reaction controllability is poor.

[0073] Add 5g of stannous octoate to 190g of hydrogenated silicone oil, stir for 10min at a speed of 500rpm / min, and drop 25g of 3-(2-hydroxyethyl)-2-oxazolidinone into the above solution, react for 1h at a temperature of 30°C. Add 90g of hydroxyl-containing MQ resin (molecular weight 10000) to the above solution, stir for 30min at a speed of 700rpm / min, add 345g of aluminum oxide, 50g of cerium oxide and 132.5g of zinc oxide in three times, stir for 5min each time adding a batch of powder, at a speed of 100rpm / min; after fully mixing, add 1.5g of hexamethylsilazane and 5g of black slurry, treat at 170°C for 2h, and cool to 40°C.

[0074] 51g of aromatic isocyanate TDI, 30g of silane coupling agent KH570, 22g of antioxidant 1035 and 27g of pentahydroxymethyl melamine were added to the above-mentioned base rubber in sequence, and mixed and stirred for 0.5h under vacuum conditions at a stirring speed of 200rpm / min and the vacuum degree was maintained at -0.09Mpa.

[0075] Under nitrogen protection, 26 g of stannous octoate was added and the mixture was stirred for 20 minutes at a stirring speed of 100 rpm / min. The material temperature was controlled at 30° C. during stirring.

[0076] In an airtight condition, the rubber material is packaged and pressed from the kettle into the rubber hose using a press and stored at room temperature.

[0077] Comparative Example 3

[0078] Compared with Example 3, the difference is that hexamethylolmelamine is not used.

[0079] 3 g of dibutyltin diisooctanoate was added to 155 g of hydrogen-terminated polydimethylsiloxane RH-H518, and stirred for 10 min at a speed of 500 rpm / min. 20.1 g of 3-hydroxyisoxazole was added dropwise to the above solution. The reaction time was 2 h and the reaction temperature was 20°C.

[0080] Add 148g of hydroxyl-containing MQ resin (molecular weight 5000) to the above solution, stir for 10min at a speed of 500rpm / min, add 345g of aluminum oxide, 50g of cerium oxide and 97g of zinc oxide in three times, stir for 5min each time a batch of powder is added, and the speed is 100rpm / min; after fully mixing, add 2.9g of stearic acid and 2g of black slurry, treat at 110℃ for 2h, and cool to 25℃.

[0081] 76 g of blocked aromatic isocyanate Desmodur CT, 21 g of silane coupling agent KH540 and 29 g of antioxidant 168 were added to the above base rubber in sequence, and mixed and stirred for 0.5 h under vacuum conditions at a stirring speed of 100 rpm / min and the vacuum degree was maintained at -0.09 MPa.

[0082] Under nitrogen protection, 12 g of 1,3-propanedioxytitanium bis(ethyl acetoacetate) complex (T9000) was added and mixed and stirred for 20 min at a stirring speed of 100 rpm / min. The material temperature was controlled at 25° C. during stirring.

[0083] In an airtight condition, the rubber material is packaged and pressed from the kettle into the rubber hose using a press and stored at room temperature.

[0084] Sample test:

[0085] The samples in Examples 1, 2, and 3 were compared with Comparative Examples 1, 2, and 3 and similar products on the market (XE13-A8341), and the test items were: curing time, 350°C high temperature resistance, shear strength attached to metal aluminum sheets, and colloid tensile strength. The test results are shown in the table below.

[0086]

[0087]

[0088] The main analysis and characterization methods are as follows:

[0089] 1. Tensile strength and elongation at break performance test

[0090] The tensile strength and elongation at break were tested using a CMT4202 universal material testing machine. The room temperature vulcanized foam silicone rubber product was conditioned in a standard environment for more than 16 hours at a temperature of 23°C ± 2°C and a relative humidity of 50° ± 5%. The sample was 2 mm thick and was a dumbbell-shaped specimen. The sample was prepared and tested in accordance with the national standard GB / TF6344-2008.

[0091] 2. Shear strength test refers to GBT 7124-2008

[0092] The adhesive layer is applied between two aluminum sheets, the thickness of the adhesive layer is 0.2mm, and the length of the bonding surface is about 12.5mm±0.25mm. The shear strength performance of the sample is tested on a CMT4202 universal testing machine, and the ambient temperature is 23℃±2℃.

[0093] It can be clearly seen from the above table that the one-component dual-curing high-temperature resistant organic silicone adhesive prepared by the present invention has good adhesion and high-temperature resistance. It can be seen from the curing time data that the colloid cures very quickly at high temperature and has a certain strength, which can meet the needs of assembly line production operations; after thermal curing, it can be seen from the tensile strength and shear strength data that the bonding strength of the colloid can meet the needs of component bonding and fixation; and after 7 days of room temperature curing, it can be seen from the increase in tensile strength and shear strength data that the bonding strength of the colloid can meet the needs of PTC component bonding and fixation and application; it can be seen from the 350°C aging data that the colloid has good heat resistance and can remain at long-term high temperature without cracking or falling off. Therefore, the one-component dual-curing high-temperature resistant organic silicone adhesive prepared by the present invention has good high-temperature resistance and good adhesion, which meets the high-temperature resistance requirements of PTC component bonding.

[0094] The above is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this technical field, without departing from the principle of the present invention, several deductions or equivalent substitutions can be made without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A dual-curing single-component high-temperature resistant adhesive, characterized in that: The high temperature resistant glue comprises the following components:

2. The high temperature resistant adhesive according to claim 1, characterized in that: The hydroxyoxazolidine-modified hydrogenated silicone oil is prepared by dehydrogenating hydrogenated silicone oil and a hydroxyoxazolidine compound; Preferably, the hydrogen-containing silicone oil is one or more of end-side hydrogen-containing silicone oil, side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, and single-end hydrogen-containing silicone oil; Preferably, the hydroxyoxazolidine compound is a dehydration product of the reaction of diethanolamine and an aldehyde compound; Preferably, in the dehydrogenation preparation, the amount of hydrogen-containing silicone oil is 5 to 30 parts, preferably 10 to 25 parts, and the amount of the hydroxyoxazolidine compound is 0.1 to 5 parts, preferably 1 to 3 parts.

3. The high temperature resistant adhesive according to claim 1 or 2, characterized in that: The hydroxyl-containing MQ resin is a co-hydrolyzate of tetraalkoxysilane (Q unit) and trimethylethoxysilane (M unit); Preferably, the co-hydrolyzate has an M / Q value of 0.60-0.80, a molecular weight of 5000-20,000, and a hydroxyl content of 1.0-6.0 wt%.

4. The high temperature resistant adhesive according to any one of claims 1 to 3, characterized in that: The filler is one or more of nitrides, oxides, and carbides, preferably one or more of aluminum oxide, zinc oxide, cerium oxide, silicon carbide, boron nitride, aluminum nitride, and iron oxide; And / or, the surface treatment agent is one or more of silane compounds, preferably one or more of vinyltrioxymethylsilane, hexamethyldisilazane, hexamethyldisiloxane, octamethyltrisiloxane, octamethylcyclotetrasiloxane, and stearic acid; And / or, the adhesion promoter is one or more of an epoxy silane coupling agent, an amino silane coupling agent, and a mercapto silane coupling agent; preferably 3-glycidyloxypropyl triethoxysilane, 3-glycidyloxypropyl trimethoxysilane, 3-glycidyloxypropyl methyl dimethoxysilane, 3-glycidyloxypropyl methyl diethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, One or more of oxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane.

5. The high temperature resistant adhesive according to any one of claims 1 to 4, characterized in that: The blocked aromatic isocyanate comprises one or more of 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, diphenylmethane diisocyanate, methoxyphenyl-2,4-diisocyanate, polymethylene polyphenyl isocyanate, 3,3′-dimethoxy-4,4′-biphenyl diisocyanate, toluene-2,4,6-triisocyanate, toluene diisocyanate-trimethylolpropane, and TDI trimer, which are blocked with phenol and / or caprolactam.

6. The high temperature resistant adhesive according to any one of claims 1 to 5, characterized in that: The hydroxyl-containing melamine compound is one or more of monomethylolmelamine, dimethylolmelamine, trimethylolmelamine, tetramethylolmelamine, pentamethylolmelamine and hexamethylolmelamine.

7. A method for preparing the high temperature resistant adhesive according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: S1: The hydrogen-containing silicone oil reacts with the hydroxyoxazolidine compound to remove hydrogen; S2: adding hydroxyl-containing MQ silicone resin and filler to the modified silicone oil, mixing evenly, adding surface treatment agent for treatment, and cooling; S3: adding an adhesion promoter, a blocked aromatic isocyanate, and a melamine-containing compound to the above-mentioned base adhesive, and mixing and stirring; S4: Add titanate and / or organotin catalyst, mix and stir, and pack into high temperature resistant rubber products.

8. The preparation method according to claim 7, characterized in that: The reaction time of S1 is 1-3h, and the reaction temperature is 20-40°C; And / or, the S2 is treated at 60-180°C and cooled to below 40°C; And / or, the material temperature is controlled to be less than 40° C. during the stirring in S4.

9. A use of a high temperature resistant adhesive, wherein the high temperature resistant adhesive is the high temperature resistant adhesive described in any one of claims 1 to 6, or is the high temperature resistant adhesive prepared by the preparation method described in claim 7 or 8, and the high temperature resistant adhesive is used in the field of bonding for long-term use under high temperature conditions, preferably in the field of bonding PTC ceramic heaters.

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