A bio-based silane coupling agent, its preparation method and application

Abstract

This disclosure provides a bio-based silane coupling agent, belonging to the field of polymer materials technology. The bio-based silane coupling agent includes at least one compound with the structure shown in Formula I; wherein R is a C4-C20 alkyl group, a C3-C20 cycloalkyl group, or R... 1 It is propyl or ethylaminopropyl, R 2 For hydrogen or methyl, R 3 The molecule is methyl or ethyl, a is 0 or 1, and n is an even number from 4 to 28. The bio-based silane coupling agent disclosed herein can significantly increase the room temperature adhesion and water immersion adhesion of silicone sealants.

Description

Technical Field

[0001] This disclosure relates to the field of polymer materials technology, specifically to a bio-based silane coupling agent and its preparation method and application. Background Technology

[0002] Room temperature cured silicone rubber (RTV) exhibits excellent resistance to UV light, weathering, and high temperature and humidity. Compared to other types of sealants, its durability under harsh conditions is particularly outstanding, especially single-component RTV sealants. Due to the relatively stable silicon-oxygen bonds in its main component, it possesses excellent aging resistance and is widely used in construction, automotive, lighting, and electronics industries. Polybutylene terephthalate (PBT) possesses good heat resistance, moisture resistance, oil resistance, corrosion resistance, electrical insulation, and machinability, making it widely used in the encapsulation of electronic components. In some applications involving sealing and structural bonding, RTV is required to bond PBT materials.

[0003] Typically, conventional RTV silicone rubber uses standard silane coupling agents as tackifiers, which exhibit good adhesion to most substrates. However, its adhesion to polybutylene terephthalate (PBT) is less than ideal, with poor adhesion at room temperature and after immersion in water. Therefore, it is necessary to continuously develop specific tackifiers to improve the adhesion of RTV silicone rubber to PBT-based materials. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a bio-based silane coupling agent, its preparation method, and its application.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a bio-based silane coupling agent, wherein the bio-based silane coupling agent comprises at least one of the compounds with the structure shown in Formula I;

[0006]

[0007] Wherein, R is a C4-C20 alkyl or a C3-C20 cycloalkyl, R 1 It is propyl or ethylaminopropyl, R 2 For hydrogen or methyl, R 3 For methyl or ethyl, a is 0 or 1, and n is an even number of 4-28.

[0008] In one embodiment, R is a C4-C10 alkyl, C3-C6 cycloalkyl; and / or, n is an even number of 6-16.

[0009] In one embodiment, the bio-based silane coupling agent comprises at least one of the following compounds:

[0010]

[0011] On the other hand, a method for preparing the aforementioned bio-based silane coupling agent is provided, comprising the following steps:

[0012] Fatty acid, aminosilane coupling agent, salicylaldehyde and solvent are mixed and stirred at 5-35℃ for 10-90 min. Then C-isocyanate is added and reacted at 5-60℃ for 0.5-4 h to obtain bio-based silane coupling agent.

[0013] The molar ratio of fatty acid, aminosilane coupling agent, salicylaldehyde and C-isocyanate is 1:1-1.5:1-1.5:1.

[0014] In one embodiment, the fatty acid is one of octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, eicosanoic acid, and docosanoic acid.

[0015] In one embodiment, the aminosilane coupling agent is one of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane, aminoethylaminopropyltriethoxysilane, aminopropylmethyldimethoxysilane, aminopropylmethyltriethoxysilane, aminoethylaminopropylmethyldimethoxysilane, and aminoethylaminopropylmethyldiethoxysilane.

[0016] In one embodiment, the solvent comprises 5-50% by mass, based on the total mass of fatty acids, aminosilane coupling agents, and salicylaldehyde being 100%.

[0017] Furthermore, the application of the aforementioned bio-based silane coupling agent in the preparation of organosilicon sealants is provided.

[0018] In another aspect, an organosilicon sealant is provided, comprising the following components in parts by weight: 100 parts of polydimethylsiloxane, 1-10 parts of crosslinking agent, 5-100 parts of filler, 1-30 parts of plasticizer, 0.01-5 parts of catalyst, and 0.1-5 parts of the bio-based silane coupling agent.

[0019] In one embodiment, the polydimethylsiloxane is at least one of α,ω-dihydroxypolydimethylsiloxane and methyldimethoxy-terminated polydimethylsiloxane;

[0020] And / or, the viscosity of the polydimethylsiloxane at 25°C is 1000–150000 mPa·s;

[0021] And / or, the crosslinking agent is at least one of ketoxime silane and alkoxy silane;

[0022] And / or, the filler is at least one of calcium carbonate, diatomaceous earth, quartz sand, and silica;

[0023] And / or, the plasticizer is at least one of mineral oil and dimethyl silicone oil;

[0024] And / or, the catalyst is at least one of organotin catalysts and organotitanium catalysts.

[0025] Compared with the prior art, the beneficial effects of this invention are as follows: This disclosure provides a bio-based silane coupling agent, which has long-chain alkyl, hydroxyphenyl, amide, and alkoxysilane groups. The various groups in the molecular structure have the following effects: First, the polar hydroxyl and amide groups can form hydrogen bonds with the terminal carboxylic acids or hydroxyl groups in PBT materials, and the phenyl groups have π-π interactions with the phenyl groups in PBT. These two forces enhance the entanglement between the long-chain alkyl groups of the silane coupling agent and the butylene groups in the PBT material. Both synergistically enhance the adhesion between the silane coupling agent and the PBT material, which is stronger than the composite of single long-chain alkyl entanglement or hydrogen bonding. Furthermore, the alkoxysilane can undergo a crosslinking reaction with room temperature vulcanizing silicone rubber, thereby increasing the interaction between room temperature vulcanizing silicone rubber and PBT. Second, the presence of long-chain alkyl and phenyl groups effectively improves the compatibility of the silicone rubber system with PBT. Third, the use of natural long-chain fatty acids and salicylaldehyde gives the product a certain degree of renewability, sustainability, and environmental friendliness. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions in the embodiments of this disclosure will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0027] In this disclosure, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0028] In this disclosure, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0029] In this disclosure, there are no particular restrictions on the specific methods of dispersion and mixing.

[0030] Unless otherwise specified, all reagents or instruments used in this disclosure are commercially available products.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0032] To address the problem of poor room temperature adhesion and water immersion adhesion of RTV silicone rubber p-butyl terephthalate materials using conventional silane coupling agents as tackifiers in existing technologies.

[0033] This disclosure provides a bio-based silane coupling agent, which includes at least one of the compounds with the structure shown in Formula I;

[0034]

[0035] Wherein, R is a C4-C20 alkyl or a C3-C20 cycloalkyl, R 1 It is propyl or ethylaminopropyl, R 2 For hydrogen or methyl, R 3 For methyl or ethyl, a is 0 or 1, and n is an even number of 4-28.

[0036] The bio-based silane coupling agent with the structure shown in Formula I has long-chain alkyl, hydroxyphenyl, amide, and alkoxysilane groups in its molecular structure. These multiple groups have the following effects: First, the polar hydroxyl and amide groups can form hydrogen bonds with the terminal carboxylic acids or hydroxyl groups in PBT materials, and the phenyl groups interact with the phenyl groups in PBT through a π-π interaction. These two forces enhance the entanglement between the long-chain alkyl groups of the silane coupling agent and the butylene groups in the PBT material. Both synergistically enhance the adhesion between the silane coupling agent and the PBT material, which is stronger than the combination of single long-chain alkyl entanglement or hydrogen bonding. Furthermore, the alkoxysilane can undergo a crosslinking reaction with room-temperature vulcanizing silicone rubber, thereby increasing the interaction between room-temperature vulcanizing silicone rubber and PBT. Second, the presence of long-chain alkyl and phenyl groups effectively improves the compatibility between the silicone rubber system and PBT. Third, the use of natural long-chain fatty acids and salicylaldehyde gives the product a certain degree of renewability, sustainability, and environmental friendliness.

[0037] In formula I above, the substituents are as follows:

[0038] In C4-C20 alkyl (alkyl groups with 4-20 carbon atoms), alkyl refers to a free radical of a saturated or unsaturated aliphatic group, including straight-chain alkyl, straight-chain alkenyl, straight-chain alkynyl, branched-chain alkyl, branched-chain alkenyl, and branched-chain alkynyl.

[0039] For example, C4-C20 alkyl groups include C4-C20 saturated alkyl groups, C4-C20 alkenyl groups, and C4-C20 alkynyl groups. More preferably, straight-chain alkyl groups with 4-10 carbon atoms, branched alkyl groups with 4-10 carbon atoms, straight-chain alkenyl groups with 4-10 carbon atoms, and branched alkenyl groups with 4-10 carbon atoms are selected. Examples of alkyl groups include n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, and neopentyl; examples of alkenyl groups include vinyl, allyl, isopropenyl, and pentenyl; and examples of alkynyl groups include ethynyl, propynyl, isopropynyl, and pentyynyl.

[0040] In C3-C20 cycloalkyl (cycloalkyl with 3-20 carbon atoms), alkyl refers to the free radical of a saturated aliphatic group. More preferably, cycloalkyl with 3-6 carbon atoms is selected. Specific examples of cycloalkyl include cyclopentyl and cyclohexyl.

[0041] Specific examples of n include: 4, 6, 8, 10, 14, 16, 18, 20, 24, and 28. Preferably, n is an even number between 6 and 16.

[0042] When R is a C4-C10 alkyl or C3-C6 cycloalkyl, and n is an even number of 6-16, the resulting bio-based silane coupling agent can effectively improve the room temperature adhesion and water immersion adhesion of silicone sealants.

[0043] In one embodiment, the bio-based silane coupling agent (hereinafter referred to as coupling agent A1, coupling agent A2, coupling agent A3, coupling agent A4) comprises at least one of the following compounds:

[0044]

[0045] On the other hand, a method for preparing the aforementioned bio-based silane coupling agent is provided, comprising the following steps:

[0046] Fatty acid, aminosilane coupling agent, salicylaldehyde and solvent are mixed and stirred at 5-35℃ for 10-90 min. Then C-isocyanate is added and reacted at 5-60℃ for 0.5-4 h to obtain bio-based silane coupling agent.

[0047] The molar ratio of fatty acid, aminosilane coupling agent, salicylaldehyde and C-isocyanate is 1:1-1.5:1-1.5:1.

[0048] This disclosure yields a bio-based silane coupling agent with high yield and purity by controlling the molar ratio of raw materials, the order of addition of raw materials, and the reaction time and temperature.

[0049] The reaction equation for the bio-based silane coupling agent disclosed herein is as follows:

[0050]

[0051] Specifically, after the reaction with V-isocyanates is completed, the solvent needs to be removed to obtain a bio-based silane coupling agent.

[0052] In one embodiment, the fatty acid is one of octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, eicosanoic acid, and docosanoic acid.

[0053] In one embodiment, the aminosilane coupling agent is one of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane, aminoethylaminopropyltriethoxysilane, aminopropylmethyldimethoxysilane, aminopropylmethyltriethoxysilane, aminoethylaminopropylmethyldimethoxysilane, and aminoethylaminopropylmethyldiethoxysilane.

[0054] In one embodiment, the solvent is 5-50% by mass, based on the total mass of fatty acid, aminosilane coupling agent and salicylaldehyde as 100%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0055] Specifically, the solvent used in the preparation of the bio-based silane coupling agent in this disclosure is an alcohol solvent, such as methanol or ethanol; methanol is preferred in this disclosure.

[0056] Furthermore, the application of the aforementioned bio-based silane coupling agent in the preparation of organosilicon sealants is provided.

[0057] In another aspect, an organosilicon sealant is provided, comprising the following components in parts by weight: 100 parts of polydimethylsiloxane, 1-10 parts of crosslinking agent, 5-100 parts of filler, 1-30 parts of plasticizer, 0.01-5 parts of catalyst, and 0.1-5 parts of the bio-based silane coupling agent.

[0058] Specifically, the weight parts of the bio-based silane coupling agent can be 0.1 parts, 0.5 parts, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts, but are not limited to the listed values. Other unlisted values ​​within the scope of this disclosure are also applicable.

[0059] Specifically, the crosslinking agent can be in the following weight parts: 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts, but is not limited to the listed values. Other unlisted values ​​within the scope of this disclosure are also applicable.

[0060] Specifically, the filler may be in the following weight parts: 5 parts, 20 parts, 50 parts, 70 parts, or 100 parts, but is not limited to the listed values. Other unlisted values ​​within the scope of this disclosure are also applicable.

[0061] Specifically, the plasticizer may be present in parts by weight of 1, 5, 10, 15, 20, 25, or 30 parts, but is not limited to the listed values. Other unlisted values ​​within the scope of this disclosure are also applicable.

[0062] In one embodiment, the polydimethylsiloxane is at least one of α,ω-dihydroxy polydimethylsiloxane and methyldimethoxy-terminated polydimethylsiloxane.

[0063] In one embodiment, the viscosity of the polydimethylsiloxane at 25°C is 1000-150000 mPa·s; for example, it can be 1000 mPa·s, 5000 mPa·s, 10000 mPa·s, 30000 mPa·s, 50000 mPa·s, 70000 mPa·s, 90000 mPa·s, 120000 mPa·s, or 150000 mPa·s, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0064] In one embodiment, the crosslinking agent is at least one of ketooxime silane and alkoxysilane.

[0065] Specifically, the ketooxime silane is at least one of methyltributanone oxime silane, vinyltributanone oxime silane, and tetrabutanone oxime silane.

[0066] Specifically, the alkoxysilane is at least one of methyltrimethoxysilane, vinyltrimethoxysilane, and propyltrimethoxysilane.

[0067] In one embodiment, the filler is at least one selected from calcium carbonate, diatomaceous earth, quartz sand, and silica.

[0068] In one embodiment, the plasticizer is at least one of mineral oil and dimethyl silicone oil.

[0069] In one embodiment, the catalyst is at least one of organotin catalysts and organotitanium catalysts.

[0070] Specifically, the organotin catalyst is at least one of dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, and dibutyltin diacetylacetonate.

[0071] Specifically, the organotitanium catalyst is at least one of tetrabutyl titanate, tetratert-butyl titanate, titanium diisopropoxydiacetylacetonate, and titanium diisopropoxydiacetylacetonate.

[0072] In one embodiment, the silicone sealant of this disclosure may contain other additives, such as a first silane coupling agent, wherein the first silane coupling agent is at least one of γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexane)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexane)ethyltriethoxysilane, γ-(glycidoxy)propylmethyltrimethoxysilane, and γ-(glycidoxy)propylmethyltriethoxysilane.

[0073] It should be noted that this disclosure does not impose any particular limitation on the preparation method of the silicone sealant. Those skilled in the art can prepare it into a silicone sealant using conventional technical means, such as mixing polydimethylsiloxane, crosslinking agent, filler, plasticizer, catalyst, and the bio-based silane coupling agent evenly.

[0074] Example 1

[0075] This disclosure includes embodiments of a bio-based silane coupling agent and its preparation method.

[0076] The structural formula of the bio-based silane coupling agent implemented in this embodiment is as follows, denoted as coupling agent A1:

[0077]

[0078] The preparation method of coupling agent A1 includes the following steps:

[0079] At room temperature, lauric acid, aminopropyltrimethoxysilane, and salicylaldehyde in a molar ratio of 1:1:1 were added to a reactor equipped with a stirrer and a thermometer. Methanol was then added, with the amount of methanol being 20% ​​of the total mass of lauric acid, aminopropyltrimethoxysilane, and salicylaldehyde. The reaction was carried out under nitrogen protection and stirred at a speed of 100 rpm for 0.5 h. Then, 1 mol of tert-butylisocyanate was added at 25 °C, and the reaction was continued with stirring for 2 h. The solvent was removed by distillation to obtain coupling agent A1, which was then sealed and stored for later use.

[0080] The 1H NMR spectra of coupling agent A1 are as follows: 0.55 (2H), 0.95-1.15 (12H), 1.25-1.60 (20H), 2.15 (2H), 3.2 (2H), 3.55 (9H), 5.5 (1H), 6.6-6.9 (4H).

[0081] Example 2

[0082] This disclosure includes embodiments of a bio-based silane coupling agent and its preparation method.

[0083] The structural formula of the bio-based silane coupling agent in this embodiment is as follows, denoted as coupling agent A2:

[0084]

[0085] The preparation method of coupling agent A2 includes the following steps:

[0086] At room temperature, stearic acid, γ-aminoethylaminopropyltriethoxysilane, and salicylaldehyde in a molar ratio of 1:1:1 were added to a reactor equipped with a stirrer and a thermometer. Methanol was then added, with the amount of methanol being 5% of the total mass of stearic acid, γ-aminoethylaminopropyltriethoxysilane, and salicylaldehyde. The reaction was carried out under nitrogen protection and stirred at a speed of 100 rpm for 0.5 h. Then, 1 mol of cyclopentylisocyanate was added at 10 °C, and the reaction was continued with stirring for 3 h. The solvent was removed by distillation to obtain coupling agent A2, which was then sealed and stored for later use.

[0087] The 1H NMR spectra of coupling agent A2 are as follows: 0.55 (2H), 0.95-1.2 (12H), 1.25-1.70 (40H), 2.15 (2H), 2.55 (7H), 3.70 (6H), 5.5 (1H), 6.6-6.9 (4H).

[0088] Example 3

[0089] This disclosure includes embodiments of a bio-based silane coupling agent and its preparation method.

[0090] The structural formula of the bio-based silane coupling agent implemented in this embodiment is as follows, denoted as coupling agent A3:

[0091]

[0092] The preparation method of coupling agent A3 includes the following steps:

[0093] At room temperature, octanoic acid, γ-aminoethylaminopropylmethyldiethoxysilane, and salicylaldehyde in a molar ratio of 1:1:1 were added to a reactor equipped with a stirrer and a thermometer. Methanol was then added, with the amount of methanol being 50% of the total mass of octanoic acid, γ-aminoethylaminopropylmethyldiethoxysilane, and salicylaldehyde. The reaction was carried out under nitrogen protection and stirred at a speed of 100 rpm for 0.5 h. Then, 1 mol of cyclohexylisocyanate was added at 10 °C, and the reaction was continued with stirring for 3 h. The solvent was removed by distillation to obtain coupling agent A3, which was then sealed and stored for later use.

[0094] The 1H NMR spectra of coupling agent A3 are as follows: 0.15 (3H), 0.65 (2H), 0.95-1.5 (25H), 1.70-1.85 (6H), 2.15 (2H), 2.55-2.65 (7H), 3.80 (4H), 5.5 (1H), 6.6-6.9 (4H).

[0095] Example 4

[0096] This disclosure includes embodiments of a bio-based silane coupling agent and its preparation method.

[0097] The structural formula of the bio-based silane coupling agent in this embodiment is as follows, denoted as coupling agent A4:

[0098]

[0099] The preparation method of coupling agent A4 includes the following steps:

[0100] At room temperature, stearic acid, γ-aminoethylaminopropylmethyldiethoxysilane, and salicylaldehyde in a molar ratio of 1:1:1 were added to a reactor equipped with a stirrer and a thermometer. Methanol was then added, with the amount of methanol being 20% ​​of the total mass of stearic acid, γ-aminoethylaminopropylmethyldiethoxysilane, and salicylaldehyde. The reaction was carried out under nitrogen protection and stirred at a speed of 100 rpm for 0.5 h. Then, 1 mol of tert-octylisocyanate was added at 25 °C, and the reaction was continued with stirring for 3 h. The solvent was removed by distillation to obtain coupling agent A4, which was then sealed and stored for later use.

[0101] The 1H NMR spectra of coupling agent A4 are as follows: 0.15 (3H), 0.65 (2H), 0.95–1.05 (12H), 1.20–1.40 (46H), 2.15 (2H), 2.65 (2H), 3.80 (4H), 5.7 (1H), 6.6–6.9 (4H).

[0102] Application Example 1

[0103] This application example provides a one-component deoxime-type silicone sealant, the preparation method of which is as follows:

[0104] 60 parts by weight of α,ω-dihydroxypolydimethylsiloxane, 5 parts by weight of dimethyl silicone oil, 35 parts by weight of modified calcium carbonate with an average particle size of 80 nm, 3.5 parts by weight of methyl tributanone oxime silane, 1.2 parts by weight of vinyl tributanone oxime silane, 1.3 parts by weight of coupling agent A1, and 0.03 parts by weight of dibutyltin dilaurate were degassed and mixed in a universal mixer to obtain an organosilicon sealant.

[0105] Among them, α,ω-dihydroxypolydimethylsiloxane has a viscosity of 50 Pa·s at 25℃;

[0106] Dimethyl silicone oil has a viscosity of 350 mPa·s at 25°C;

[0107] The modified calcium carbonate is prepared by mixing stearic acid and calcium carbonate evenly, and the mass of stearic acid is 2.0% of the mass of calcium carbonate.

[0108] Application Example 2

[0109] This application example provides a one-component deoxime-type silicone sealant, the preparation method of which is as follows:

[0110] 60 parts by weight of α,ω-dihydroxypolydimethylsiloxane, 5 parts by weight of dimethyl silicone oil, 35 parts by weight of modified calcium carbonate with an average particle size of 80 nm, 3.5 parts by weight of methyl tributanone oxime silane, 1.2 parts by weight of vinyl tributanone oxime silane, 1.7 parts by weight of coupling agent A2, 0.1 parts by weight of KH-560, and 0.03 parts by weight of dibutyltin dilaurate were degassed and mixed in a universal mixer to obtain an organosilicon sealant.

[0111] Among them, α,ω-dihydroxypolydimethylsiloxane has a viscosity of 50 Pa·s at 25℃;

[0112] Dimethyl silicone oil has a viscosity of 350 mPa·s at 25°C;

[0113] The modified calcium carbonate is prepared by mixing stearic acid and calcium carbonate evenly, and the mass of stearic acid is 2.0% of the mass of calcium carbonate.

[0114] Application Example 3

[0115] This application example provides a one-component deoxime-type silicone sealant, the preparation method of which is as follows:

[0116] 60 parts by weight of α,ω-dihydroxypolydimethylsiloxane, 5 parts by weight of dimethyl silicone oil, 35 parts by weight of modified calcium carbonate with an average particle size of 80 nm, 3.5 parts by weight of methyl tributanone oxime silane, 1.2 parts by weight of vinyl tributanone oxime silane, 1.4 parts by weight of coupling agent A3, 0.1 parts by weight of KH-560, and 0.03 parts by weight of dibutyltin dilaurate were degassed and mixed in a universal mixer to obtain an organosilicon sealant.

[0117] Among them, α,ω-dihydroxypolydimethylsiloxane has a viscosity of 50 Pa·s at 25℃;

[0118] Dimethyl silicone oil has a viscosity of 350 mPa·s at 25°C;

[0119] The modified calcium carbonate is prepared by mixing stearic acid and calcium carbonate evenly, and the mass of stearic acid is 2.0% of the mass of calcium carbonate.

[0120] Application Example 4

[0121] This application example provides a one-component deoxime-type silicone sealant, the preparation method of which is as follows:

[0122] 60 parts by weight of α,ω-dihydroxypolydimethylsiloxane, 5 parts by weight of dimethyl silicone oil, 35 parts by weight of modified calcium carbonate with an average particle size of 80 nm, 3.5 parts by weight of methyl tributanone oxime silane, 1.2 parts by weight of vinyl tributanone oxime silane, 1.6 parts by weight of coupling agent A4, and 0.03 parts by weight of dibutyltin dilaurate were degassed and mixed in a universal mixer to obtain an organosilicon sealant.

[0123] Among them, α,ω-dihydroxypolydimethylsiloxane has a viscosity of 50 Pa·s at 25℃;

[0124] Dimethyl silicone oil has a viscosity of 350 mPa·s at 25°C;

[0125] The modified calcium carbonate is prepared by mixing stearic acid and calcium carbonate evenly, and the mass of stearic acid is 2.0% of the mass of calcium carbonate.

[0126] Comparative Application Example 1

[0127] This comparative application example provides a one-component deoxime type silicone sealant, the only difference between which is the preparation method and application example 3: 1.4 parts by weight of γ-aminopropyltriethoxysilane is used to replace 1.4 parts by weight of coupling agent A3, and the remaining components and amounts are the same as in application example 3.

[0128] Comparative Application Example 2

[0129] This comparative application example provides a one-component deoxime type silicone sealant, the only difference between which is the preparation method and application example 3: 1.4 parts by weight of γ-aminoethylaminopropyltrimethoxysilane is used to replace 1.4 parts by weight of coupling agent A3, and the remaining components and amounts are the same as in application example 3.

[0130] Performance testing

[0131] The silicone sealants obtained from Application Examples 1-4 and Comparative Application Examples 1-2 were used to prepare H-type adhesiveness test specimens on Al-PBT substrate according to the method provided in Chapter 7 of GB / T13477.8-2002. The specimens were then cured for 7 days at a temperature of (23±2)℃ and a relative humidity of (50±5)%, and performance tests were conducted. The test results are shown in Table 1.

[0132] Table 1

[0133]

[0134] As shown in Table 1, the silicone sealant prepared using the bio-based silane coupling agent disclosed herein exhibits a bonding failure area of ​​less than 10%, a bonding strength greater than 0.80 MPa, and a bonding strength retention rate greater than 80% after being immersed in water for 28 days and then exposed to ultraviolet light for 168 hours at room temperature. In contrast, the silicone sealant prepared using conventional coupling agents completely debonded after being immersed in water for 28 days and then exposed to ultraviolet light for 168 hours. This indicates that the bio-based silane coupling agent disclosed herein can significantly increase the room temperature adhesion and water immersion adhesion of silicone sealants.

[0135] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A bio-based silane coupling agent, characterized in that, The bio-based silane coupling agent includes at least one of the compounds with the structure shown in Formula I; Wherein, R is a C4-C20 alkyl or a C3-C20 cycloalkyl, R 1 It is propylene or ethylaminopropylene, R 2 It is methyl, R 3 For methyl or ethyl, a is 0 or 1, and n is an even number of 4-28.

2. The bio-based silane coupling agent as described in claim 1, characterized in that, The R is a C4-C10 alkyl or C3-C6 cycloalkyl; and / or the n is an even number of 6-16.

3. The bio-based silane coupling agent as described in claim 1, characterized in that, The bio-based silane coupling agent includes at least one of the following compounds: 。 4. The method for preparing the bio-based silane coupling agent according to any one of claims 1-3, characterized in that, Includes the following steps: Fatty acid, aminosilane coupling agent, salicylaldehyde and solvent are mixed and stirred at 5-35℃ for 10-90 min. Then C-isocyanate is added and reacted at 5-60℃ for 0.5-4 h to obtain bio-based silane coupling agent. The molar ratio of fatty acids, aminosilane coupling agents, salicylaldehyde, and C-isocyanates is 1:1-1.5:1-1.5:

1.

5. The preparation method according to claim 4, characterized in that, The fatty acid is one of the following: octanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, eicosanoic acid, and docosanoic acid.

6. The preparation method according to claim 4, characterized in that, The aminosilane coupling agent is one of aminopropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane, aminoethylaminopropyltriethoxysilane, aminopropylmethyldimethoxysilane, aminopropylmethyldiethoxysilane, aminoethylaminopropylmethyldimethoxysilane, and aminoethylaminopropylmethyldiethoxysilane.

7. The preparation method according to claim 4, characterized in that, The solvent comprises 5-50% of the total mass of fatty acids, aminosilane coupling agents and salicylaldehyde, which is 100% of the total mass.

8. The use of the bio-based silane coupling agent as described in any one of claims 1-3 in the preparation of organosilicon sealants.

9. An organosilicon sealant, characterized in that, It comprises the following components in parts by weight: 100 parts of polydimethylsiloxane, 1-10 parts of crosslinking agent, 5-100 parts of filler, 1-30 parts of plasticizer, 0.01-5 parts of catalyst, and 0.1-5 parts of bio-based silane coupling agent as described in any one of claims 1-3.

10. The silicone sealant as described in claim 9, characterized in that, The polydimethylsiloxane is at least one of α,ω-dihydroxy polydimethylsiloxane and methyldimethoxy-terminated polydimethylsiloxane; And / or, the viscosity of the polydimethylsiloxane at 25°C is 1000~150000 mPa•s; And / or, the crosslinking agent is at least one of ketoxime silane and alkoxy silane; And / or, the filler is at least one of calcium carbonate, diatomaceous earth, quartz sand, and silica; And / or, the plasticizer is at least one of mineral oil and dimethyl silicone oil; And / or, the catalyst is at least one of organotin catalysts and organotitanium catalysts.

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