Polyalkoxyaminosilane coupling agent and preparation method thereof, and dealcoholized transparent adhesive and preparation method thereof

Abstract

The present invention belongs to the technical field of preparation of organosilicon materials, and specifically relates to a polyalkoxyaminosilane coupling agent and a preparation method thereof, as well as a dealcoholization type transparent adhesive and a preparation method thereof. The following preparation steps are included: (1) long-chain alkoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and a solvent are added to a reactor, and the mixture is stirred and mixed at room temperature to obtain a raw material mixture; (2) deionized water and the solvent are mixed to obtain a diluted solution, and the diluted solution is dripped into the raw material mixture, heated, and kept warm for reaction; deionization is performed under negative pressure conditions, and low molecular weight substances are removed by distillation to obtain an intermediate product; (3) the intermediate product is mixed evenly with methacryloxysilane, heated, and then a loaded catalyst is added, and the reaction is kept warm, filtered, deionized, and cooled to obtain. The present invention can accelerate the deep curing of the dealcoholization type transparent adhesive, and at the same time, the surface wetting and water-resistant bonding of the polyolefin plastic substrate are significantly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of organic silicon materials, and in particular relates to a polyalkoxyaminosilane coupling agent and a preparation method thereof, and a dealcoholized transparent adhesive and a preparation method thereof. Background Art

[0002] Silicone rubber is one of the most important products of polysiloxane. Dealcoholized room temperature vulcanized silicone rubber is generally made of hydroxyl-terminated polydimethylsiloxane as the base rubber, methyltrimethoxysilane as the crosslinking agent, active nano-calcium carbonate and fumed silica as the reinforcing materials, and is prepared in combination with coupling agents, catalysts, etc. With the rapid development of 5G networks, photovoltaic industry, electronic appliances, new energy vehicles and other industries, dealcoholized room temperature vulcanized silicone rubber has excellent weather resistance, high and low temperature resistance, radiation resistance, good sealing, no corrosion to most substrates, no pollution, non-toxic and environmentally friendly, easy to use and low price. It is widely used in many fields such as construction, electronic appliances, aerospace, automobile manufacturing, solar photovoltaic industry, etc. However, the dealcoholized transparent silicone sealant has poor bonding performance to most polyolefin plastic substrates, especially the water-resistant bonding strength is weak. At present, the silane coupling agents widely used in dealcoholized transparent silicone sealants mainly include N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, (3-glycidylpropoxy)trimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. The addition of amino coupling agents containing primary amino groups to dealcoholized transparent silicone sealants will cause yellowing and affect their use; while traditional short-chain silane coupling agents such as 3-methacryloxypropyltrimethoxysilane and (3-glycidylpropoxy)trimethoxysilane have poor water-resistant adhesion to substrates.

[0003] In the Chinese invention patent application publication number CN112300395A, an amino copolymer silane coupling agent was prepared, which was mainly used for the modification of furan resin to increase its storage stability and enhance its tensile strength and other properties. In the Chinese invention patent application publication number CN105440068A, an acryloxy aminosilane was prepared, which was mainly used in glass fiber sizing, but no application research was conducted on the water-resistant bonding performance of polyolefin plastic substrates.

[0004] In summary, the silane coupling agents currently used in dealcoholized transparent silicone sealants on the market have poor water-resistant bonding properties to polyolefin plastic substrates. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a polyalkoxy aminosilane coupling agent and a preparation method thereof. The polyalkoxy aminosilane coupling agent has a multifunctional functional group structure, contains both a hydrophobic long-chain alkyl group and an acyloxy, di-secondary amine amino group, and a polyalkoxy active group participating in a cross-linking reaction, which can accelerate the deep curing of the dealcoholization type transparent adhesive, and at the same time has a significant performance improvement on the surface wetting and water-resistant bonding performance of the polyolefin plastic substrate, and is also conducive to improving the problem of yellowing of the dealcoholization type transparent adhesive caused by traditional amino coupling agents. The present invention also provides a dealcoholization type transparent adhesive prepared by using the polyalkoxy aminosilane coupling agent and a preparation method thereof.

[0006] The preparation method of the polyalkoxyaminosilane coupling agent of the present invention comprises the following preparation steps: (1) adding long-chain alkoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and solvent into a reactor, stirring and mixing them uniformly at room temperature to obtain a raw material mixed liquid; the molar ratio of the long-chain alkoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and the solvent is 1:(0.5-1.5):(1.5-2.5);

[0007] (2) Mix deionized water and solvent in a molar ratio of 1:1 to obtain a diluted deionized water solution, and drip the diluted deionized water solution into the raw material mixture. After the dripping is completed, heat the mixture to 70-85°C and keep the temperature to react for 6-8 hours; perform deionization under negative pressure conditions (vacuum degree <-0.08MPa) to distill off low molecular weight substances to obtain an intermediate product;

[0008] (3) The intermediate product and methacryloxysilane are mixed evenly, the temperature is raised to 75-95° C., and a supported catalyst is added. The mixture is kept warm for 6-8 hours. After the reaction is completed, the mixture is filtered, deionized, and cooled to room temperature to obtain the polyalkoxyaminosilane coupling agent. The molar ratio of methacryloxysilane to long-chain alkoxysilane is 1:1.

[0009] The intermediate product has a chemical structure as shown in formula (I), and the final product, i.e., the polyalkoxyaminosilane coupling agent, has a chemical structure as shown in formula (II). In formula (I) and formula (II), R1 is a carbon number of C3~C 16 R2 is an alkoxy group with a carbon number of C1 to C4.

[0010] ,

[0011] .

[0012] Preferably, the long-chain alkoxysilane is one of n-dodecyltrimethoxysilane, n-hexyltriethoxysilane, n-propyltrimethoxysilane, cyclohexyltrimethoxysilane, n-octyltrimethoxysilane and n-octyltriethoxysilane, and more preferably n-octyltrimethoxysilane.

[0013] Preferably, the solvent is one of methanol and ethanol, more preferably methanol.

[0014] Preferably, the methacryloxysilane is one of 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane, and more preferably 3-methacryloxypropyltrimethoxysilane.

[0015] Preferably, the ratio of the molar number of the solvent in step (2) to the sum of the molar numbers of the long-chain alkoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in step (1) is 1:1.

[0016] Preferably, the supported catalyst carrier supports a base catalyst, wherein the carrier is one of porous silica gel, porous alumina, activated carbon, and porous molecular sieve, and the base catalyst is one of alkali metal hydroxide and strong alkaline metal salt. More preferably, the porous molecular sieve supports a strong alkali metal oxide.

[0017] The polyalkoxyaminosilane coupling agent of the present invention is prepared by adopting the above preparation method.

[0018] The dealcoholized transparent adhesive prepared by using the above-mentioned polyalkoxyaminosilane coupling agent of the present invention comprises the following components by weight:

[0019] 100 parts of alkoxy-terminated polysiloxane,

[0020] 50 parts of dimethyl silicone oil,

[0021] 15-20 parts of hydrophobic fumed silica,

[0022] Cross-linking agent 5~10 parts,

[0023] 1~4 parts of polyalkoxy aminosilane coupling agent,

[0024] 1~3 parts of catalyst.

[0025] Preferably, the viscosity of alkoxy-terminated polysiloxane at 25°C is 40-80 Pa•s; the viscosity of dimethyl silicone oil at 25°C is 0.15-0.35 Pa•s; the crosslinking agent is one or two of methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane, and vinyltrimethoxysilane; and the catalyst is dibutyltin dilaurate.

[0026] The method for preparing the dealcoholized transparent adhesive of the present invention comprises the following steps:

[0027] S1. Add alkoxy-terminated polysiloxane, dimethyl silicone oil and crosslinking agent into a high-speed disperser, and stir at high speed (speed 100-800 rpm) for 30-40 min under negative pressure (vacuum degree <-0.08 MPa);

[0028] S2. Add hydrophobic fumed silica and disperse at high speed (speed 100-800 rpm) for 20 min, and continue to stir at high speed (speed 100-800 rpm) for 20 min under negative pressure (vacuum degree <-0.08 MPa);

[0029] S3. Add polyalkoxyaminosilane coupling agent and catalyst, and stir at high speed (rotation speed 100-800 rpm) for 30-40 min under negative pressure (vacuum degree <-0.08 MPa).

[0030] The existing dealcoholization transparent adhesive crosslinking agent has low reaction activity and slow deep curing speed. The traditional coupling agent has poor water-resistant bonding performance to polyolefin plastic substrates. The coupling agent with primary amine amino active groups causes the dealcoholization transparent adhesive to turn yellow. In view of the above problems, the polyalkoxy amino coupling agent of the present invention hydrolyzes and polycondenses the hydrophobic long-chain alkoxy group with the coupling agent with diamino active groups to generate a macromolecular coupling agent with active amino groups and hydrophobic functional groups, and then utilizes the -C=H-unsaturated bond in methacryloxysilane and the primary amine -NH2-active group in the hydrolysis and polycondensation macromolecular coupling agent to heat and catalyze the reaction to generate a silane coupling agent with a hydrophobic long-chain alkyl group, as well as acyloxy, di-secondary amine amino groups and polyalkoxy active groups participating in the crosslinking reaction.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The polyalkoxyaminosilane coupling agent of the present invention enhances the hydrophobicity of the silane coupling agent by introducing a long-chain alkoxy group, which helps to improve the water-resistant bonding performance of the dealcoholized transparent adhesive to the polyolefin plastic substrate.

[0033] (2) The polyalkoxyaminosilane coupling agent of the present invention introduces an acryloxy group, which increases the wetting effect of the silane coupling agent on the surface of the polyolefin plastic substrate, and helps to improve the water-resistant bonding performance of the dealcoholized transparent adhesive to the polyolefin plastic substrate.

[0034] (3) The polyalkoxyaminosilane coupling agent of the present invention introduces a large number of secondary amine amino groups, which enhances the surface bonding strength of the dealcoholized transparent adhesive to the polyolefin plastic substrate and solves the problem of yellowing of the dealcoholized transparent adhesive caused by the primary amine active amino groups.

[0035] (4) The polyalkoxyaminosilane coupling agent of the present invention introduces a large number of alkoxy active groups, which increases the cross-linking reaction active points of the dealcoholized transparent adhesive during the curing process and accelerates the deep curing of the dealcoholized transparent adhesive.

[0036] (5) The raw materials of the present invention are cheap, the preparation process is simple, and the prepared dealcoholized transparent adhesive is easy to construct. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the infrared spectrum of the polyalkoxyaminosilane coupling agent of Example 1. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments.

[0039] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0040] Example 1

[0041] The preparation method of the polyalkoxyaminosilane coupling agent comprises the following preparation steps: adding 111g (0.5mol) of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 117g (0.5mol) of n-octyltrimethoxysilane and 32g (1mol) of methanol into a three-necked flask, stirring for 30min to mix evenly; weighing 32g (1mol) of methanol and 18g (1mol) of deionized water to mix evenly to obtain a diluted solution of deionized water, and slowly dripping the diluted solution of deionized water into the three-necked flask (1h or more) The reaction mixture was stirred at a constant rate (within 100 °C for 2 hours at a constant dropping speed). After the addition was completed, the temperature was raised to 85 °C and the mixture was kept warm for 8 hours. The mixture was desorbed under negative pressure (vacuum degree <-0.08 MPa) and low molecular weight was removed by distillation to obtain an intermediate product. 124 g (0.5 mol) of 3-methacryloxypropyltrimethoxysilane was added and stirred evenly. The mixture was heated to 95 °C and a porous molecular sieve-supported sodium ethoxide catalyst was added. The mixture was kept warm for 6 hours. The mixture was filtered, desorbed and cooled to room temperature to obtain the polyalkoxyaminosilane coupling agent.

[0042] Example 2

[0043] The preparation method of the polyalkoxyaminosilane coupling agent comprises the following preparation steps: adding 111g (0.5mol) of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 145g (0.5mol) of n-dodecyltrimethoxysilane, and 32g (1mol) of methanol into a three-necked flask, stirring for 30min to mix evenly; weighing 32g (1mol) of methanol and 18g (1mol) of deionized water to mix evenly to obtain a diluted solution of deionized water, and slowly dripping the diluted solution of deionized water into the three-necked flask (1h or more) The reaction mixture was stirred at a constant rate (within 100 °C and a constant dropping speed), and the stirring state was maintained during the dropping. After the dropping was completed, the temperature was raised to 70 °C and the reaction was kept warm for 8 hours. The product was desorbed under negative pressure (vacuum degree <-0.08 MPa) and low molecular weight products were removed by distillation to obtain an intermediate product. 124 g (0.5 mol) of 3-methacryloxypropyltrimethoxysilane was added and stirred evenly. The product was heated to 75 °C and activated carbon-supported alkali metal lithium hydroxide catalyst was added. The reaction was kept warm for 7 hours. The product was filtered, desorbed and cooled to room temperature to obtain the polyalkoxyaminosilane coupling agent.

[0044] Example 3

[0045] The preparation method of the polyalkoxyaminosilane coupling agent comprises the following preparation steps: adding 222g (1mol) of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 276.5g (1mol) of n-octyltriethoxysilane, and 115g (2.5mol) of ethanol into a three-necked flask, stirring for 30 minutes to mix evenly; weighing 92g (2mol) of ethanol and 18g (1mol) of deionized water to mix evenly to obtain a diluted solution of deionized water, and slowly dripping the diluted solution of deionized water into the three-necked flask ( 1h, constant dropping speed), keep stirring during the dropping, after the dropping is completed, raise the temperature to 80°C, keep warm and react for 8h; degassing is carried out under negative pressure conditions (vacuum degree <-0.08MPa), low molecules are distilled off to obtain an intermediate product, 248g (1mol) of 3-methacryloxypropyltrimethoxysilane is added, stirred evenly, the temperature is raised to 85°C, and activated carbon-supported sodium ethanol catalyst is added, and the reaction is kept warm for 8h, filtered, degassed, and cooled to room temperature to obtain the polyalkoxyaminosilane coupling agent.

[0046] Example 4

[0047] The preparation method of the polyalkoxyaminosilane coupling agent comprises the following preparation steps: adding 333.5 g (1.5 mol) of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 204 g (1 mol) of cyclohexyltrimethoxysilane, and 80 g (2.5 mol) of methanol into a three-necked flask, stirring for 30 minutes to mix evenly; weighing 80 g (2.5 mol) of methanol and 18 g (1 mol) of deionized water, mixing evenly to obtain a diluted solution of deionized water, and slowly dripping the diluted solution of deionized water into the three-necked flask. (within 1h, constant dropping speed), keep stirring during the dropping, after the dropping is completed, raise the temperature to 85°C, and keep the temperature for 7h; remove the low molecular weight under negative pressure conditions (vacuum degree <-0.08MPa), distill and remove the low molecular weight to obtain an intermediate product, add 290g (1mol) of 3-methacryloxypropyltriethoxysilane, stir evenly, raise the temperature to 90°C, add porous silica gel-supported sodium ethanol catalyst, continue to keep the temperature for 7h, filter, remove the low molecular weight, and cool to room temperature to obtain the polyalkoxyaminosilane coupling agent.

[0048] Example 5

[0049] The preparation method of the polyalkoxyaminosilane coupling agent comprises the following preparation steps: adding 111g (0.5mol) of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 248g (1mol) of n-hexyltriethoxysilane, and 69g (1.5mol) of ethanol into a three-necked flask, stirring for 30min to mix evenly; weighing 69g (1.5mol) of ethanol and 18g (1mol) of deionized water, mixing evenly to obtain a diluted solution of deionized water, and slowly dripping the diluted solution of deionized water into the three-necked flask (1mol) to obtain a diluted solution of deionized water; h, constant dropping speed), keep stirring during the dropping, after the dropping is completed, raise the temperature to 85°C, and keep the reaction warm for 6h; degassing is carried out under negative pressure conditions (vacuum degree <-0.08MPa), low molecules are removed by distillation to obtain an intermediate product, 234g (1mol) of 3-acryloxypropyltrimethoxysilane is added, stirred evenly, the temperature is raised to 95°C, and porous silica gel-supported alkali metal sodium hydroxide catalyst is added, and the reaction is kept warm for 8h, filtered, degassed, and cooled to room temperature to obtain the polyalkoxyaminosilane coupling agent.

[0050] Example 6

[0051] The preparation method of the polyalkoxyaminosilane coupling agent comprises the following preparation steps: adding 111g (0.5mol) of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 82g (0.5mol) of n-propyltrimethoxysilane, and 32g (1mol) of methanol into a three-necked flask, stirring for 30min to mix evenly; weighing 32g (1mol) of methanol and 18g (1mol) of deionized water, mixing evenly to obtain a diluted solution of deionized water, and slowly dripping the diluted solution of deionized water into the three-necked flask (within 1h). , constant dropping speed), keep stirring during the dropping, after the dropping is completed, raise the temperature to 85°C, and keep warm for reaction for 8 hours; degassing is carried out under negative pressure conditions (vacuum degree <-0.08MPa), low molecules are removed by distillation to obtain an intermediate product, 124g (0.5mol) of 3-methacryloxypropyltrimethoxysilane is added, stirred evenly, and porous alumina-supported sodium ethoxide catalyst is added at 85°C, and the reaction is kept warm for 8 hours, filtered, degassed, and cooled to room temperature to obtain the polyalkoxyaminosilane coupling agent.

[0052] Example 7

[0053] The method for preparing the dealcoholized transparent adhesive comprises the following steps:

[0054] First, 100 parts by mass of alkoxy-terminated polysiloxane with a viscosity of 40 Pa•s at 25°C, 50 parts by mass of dimethyl silicone oil with a viscosity of 0.35 Pa•s at 25°C, and 10 parts by mass of methyltrimethoxysilane are added to a high-speed disperser, and stirred at high speed (speed of 800 rpm) for 30 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); then 15 parts by mass of hydrophobic fumed silica are added and dispersed at high speed (speed of 500 rpm) for 20 minutes, and continued to stir at high speed (speed of 500 rpm) for 20 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); finally, 4 parts by mass of the polyalkoxyaminosilane coupling agent prepared in Example 1 and 2 parts by mass of dibutyltin dilaurate catalyst are added, and stirred at high speed (speed of 500 rpm) for 30 minutes under negative pressure conditions (vacuum degree <-0.08 MPa) to obtain a dealcoholized transparent adhesive.

[0055] Example 8

[0056] The method for preparing the dealcoholized transparent adhesive comprises the following steps:

[0057] First, 100 parts by mass of alkoxy-terminated polysiloxane with a viscosity of 80 Pa•s at 25°C, 50 parts by mass of dimethyl silicone oil with a viscosity of 0.15 Pa•s at 25°C, and 8 parts by mass of vinyltrimethoxysilane are added to a high-speed disperser, and stirred at high speed (speed of 100 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); then 20 parts by mass of hydrophobic fumed silica are added and dispersed at high speed (speed of 100 rpm) for 20 minutes, and continued to stir at high speed (speed of 100 rpm) for 20 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); finally, 3 parts by mass of the polyalkoxyaminosilane coupling agent prepared in Example 2 and 2 parts by mass of dibutyltin dilaurate catalyst are added, and stirred at high speed (speed of 100 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa) to obtain a dealcoholized transparent adhesive.

[0058] Example 9

[0059] The method for preparing the dealcoholized transparent adhesive comprises the following steps:

[0060] First, 100 parts by mass of alkoxy-terminated polysiloxane with a viscosity of 60 Pa•s at 25°C, 50 parts by mass of dimethyl silicone oil with a viscosity of 0.35 Pa•s at 25°C, and 10 parts by mass of methyltriethoxysilane are added to a high-speed disperser, and stirred at high speed (speed of 400 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); then 18 parts by mass of hydrophobic fumed silica are added and dispersed at high speed (speed of 500 rpm) for 20 minutes, and continued to stir at high speed (speed of 500 rpm) for 20 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); finally, 4 parts by mass of the polyalkoxyaminosilane coupling agent prepared in Example 3 and 2.5 parts by mass of dibutyltin dilaurate catalyst are added, and stirred at high speed (speed of 500 rpm) for 30 minutes under negative pressure conditions (vacuum degree <-0.08 MPa) to obtain a dealcoholized transparent adhesive.

[0061] Example 10

[0062] The method for preparing the dealcoholized transparent adhesive comprises the following steps:

[0063] First, 100 parts by mass of alkoxy-terminated polysiloxane with a viscosity of 50 Pa•s at 25°C, 50 parts by mass of dimethyl silicone oil with a viscosity of 0.35 Pa•s at 25°C, and 10 parts by mass of propyltrimethoxysilane are added to a high-speed disperser, and stirred at high speed (speed of 400 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); then 18 parts by mass of hydrophobic fumed silica are added and dispersed at high speed (speed of 800 rpm) for 20 minutes, and continued to stir at high speed (speed of 800 rpm) for 20 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); finally, 4 parts by mass of the polyalkoxyaminosilane coupling agent prepared in Example 4 and 2 parts by mass of dibutyltin dilaurate catalyst are added, and stirred at high speed (speed of 800 rpm) for 30 minutes under negative pressure conditions (vacuum degree <-0.08 MPa) to obtain a dealcoholized transparent adhesive.

[0064] Embodiment 11

[0065] The method for preparing the dealcoholized transparent adhesive comprises the following steps:

[0066] First, 100 parts by mass of alkoxy-terminated polysiloxane with a viscosity of 80 Pa•s at 25°C, 50 parts by mass of dimethyl silicone oil with a viscosity of 0.15 Pa•s at 25°C, and 6 parts by mass of methyltrimethoxysilane are added to a high-speed disperser, and stirred at high speed (speed of 400 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); then 18 parts by mass of hydrophobic fumed silica are added and dispersed at high speed (speed of 500 rpm) for 20 minutes, and continued to stir at high speed (speed of 500 rpm) for 20 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); finally, 4 parts by mass of the polyalkoxyaminosilane coupling agent prepared in Example 5 and 3 parts by mass of dibutyltin dilaurate catalyst are added, and stirred at high speed (speed of 500 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa) to obtain a dealcoholized transparent adhesive.

[0067] Example 12

[0068] First, 100 parts by mass of alkoxy-terminated polysiloxane with a viscosity of 80 Pa•s at 25°C, 50 parts by mass of dimethyl silicone oil with a viscosity of 0.35 Pa•s at 25°C, and 10 parts by mass of methyltrimethoxysilane are added to a high-speed disperser, and stirred at high speed (speed of 400 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); then 18 parts by mass of hydrophobic fumed silica are added and dispersed at high speed (speed of 500 rpm) for 20 minutes, and continued to stir at high speed (speed of 500 rpm) for 20 minutes under negative pressure conditions (vacuum degree <-0.08 MPa); finally, 1 part by mass of the polyalkoxyaminosilane coupling agent prepared in Example 6 and 1 part by mass of dibutyltin dilaurate catalyst are added, and stirred at high speed (speed of 500 rpm) for 40 minutes under negative pressure conditions (vacuum degree <-0.08 MPa) to obtain a dealcoholized transparent adhesive.

[0069] Comparative Example 1

[0070] The only difference between Comparative Example 1 and Example 7 is that the polyalkoxyaminosilane coupling agent is replaced by a complex coupling agent of equal mass, and the complex coupling agent is a compound of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane in a mass ratio of 1:1.

[0071] Comparative Example 2

[0072] The only difference between Comparative Example 2 and Example 7 is that the polyalkoxyaminosilane coupling agent is replaced by a complex coupling agent of equal mass, and the complex coupling agent is a compound of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and γ-aminopropyltriethoxysilane in a mass ratio of 1:1.

[0073] Comparative Example 3

[0074] The only difference between Comparative Example 3 and Example 7 is that the polyalkoxyaminosilane coupling agent is replaced by a complex coupling agent of equal mass, wherein the complex coupling agent is a compound of (3-glycidylpropoxy)trimethoxysilane and γ-aminopropyltriethoxysilane in a mass ratio of 1:1.

[0075] Performance Testing

[0076] Figure 1 Infrared spectrum of polyalkoxyaminosilane coupling agent in Example 1: measured at 1460cm -1 A strong absorption peak appears at 1722 cm -1 The characteristic peak of -CH2-C(=O)-OR indicates that the acyloxy group and the primary amino group have chemically reacted. -1A strong absorption peak appears at 780cm, which is the characteristic absorption peak of -Si-O-Si-. -1 ~790cm -1 -Si-(CH3) n The characteristic peaks of further illustrate that the long-chain alkoxysilane and the bisaminosilane undergo hydrolysis and polycondensation reaction and exist simultaneously in the prepared silane coupling agent.

[0077] The dealcoholized transparent adhesive prepared in Examples 7-12 and Comparative Examples 1-3 was tested for surface drying time, colloid curing depth, and water-resistant bonding performance to polyolefin plastic substrates (PVC, PS) in accordance with "GB / T13477 Test Methods for Building Sealing Materials" and "GB / T32369-2015 Determination of Curing Degree of Sealant". The results are shown in Table 1, where: CF-cohesive failure, AF-adhesive failure, MF-mixed failure.

[0078] Table 1 Performance test table of dealcoholized transparent adhesive of Examples 7-12 and Comparative Examples 1-3

[0079]

[0080] As can be seen from Table 1, the polyalkoxyaminosilane coupling agent prepared by the present invention effectively accelerates the deep curing speed of the dealcoholized transparent adhesive, enhances the water-resistant bonding performance of the dealcoholized transparent adhesive to polyolefin plastics (PVC, PS), and solves the problem of yellowing of the dealcoholized transparent adhesive caused by traditional amino coupling agents.

Claims

1. A method for preparing a polyalkoxyaminosilane coupling agent, characterized in that: The method comprises the following preparation steps: (1) adding long-chain alkoxysilane or cyclohexyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and a solvent into a reactor, stirring and mixing them uniformly at room temperature to obtain a raw material mixed liquid; (2) Mix deionized water and solvent evenly to obtain a diluted deionized water solution, and drip the diluted deionized water solution into the raw material mixture. After the dripping is completed, heat the mixture to 70-85°C and keep the temperature to react for 6-8 hours; remove the low molecular weight substances by distillation under negative pressure to obtain an intermediate product; (3) uniformly mixing the intermediate product and methacryloxysilane, raising the temperature to 75-95° C., adding a supported catalyst, and reacting at the temperature for 6-8 hours, filtering, degassing, and cooling to obtain the polyalkoxyaminosilane coupling agent; The long-chain alkoxysilane is one of n-dodecyltrimethoxysilane, n-hexyltriethoxysilane, n-propyltrimethoxysilane, n-octyltrimethoxysilane and n-octyltriethoxysilane; in step (1), the molar ratio of the long-chain alkoxysilane or cyclohexyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and the solvent is 1:(0.5-1.5):(1.5-2.5); The methacryloxysilane is one of 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane; The supported catalyst carrier supports an alkali catalyst, wherein the carrier is one of porous silica gel, porous alumina, activated carbon, and porous molecular sieve, and the alkali catalyst is one of alkali metal hydroxide and strong alkaline metal salt.

2. The method for preparing a polyalkoxyaminosilane coupling agent according to claim 1, characterized in that: The solvent is one of methanol and ethanol.

3. The method for preparing a polyalkoxyaminosilane coupling agent according to claim 1, characterized in that: The ratio of the molar number of the solvent in step (2) to the sum of the molar numbers of the long-chain alkoxysilane or cyclohexyltrimethoxysilane and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane in step (1) is 1:

1.

4. A polyalkoxyaminosilane coupling agent, characterized in that: The method is prepared by any one of claims 1 to 3.

5. A dealcoholized transparent adhesive prepared by using the polyalkoxyaminosilane coupling agent according to claim 4, characterized in that: Prepared by including the following components: 100 parts of alkoxy-terminated polysiloxane, 50 parts of dimethyl silicone oil, 15-20 parts of hydrophobic fumed silica, Cross-linking agent 5~10 parts, 1~4 parts of polyalkoxy aminosilane coupling agent, 1~3 parts of catalyst; The crosslinking agent is one or two of methyltrimethoxysilane, methyltriethoxysilane, propyltrimethoxysilane and vinyltrimethoxysilane; and the catalyst is dibutyltin dilaurate.

6. The dealcoholized transparent adhesive according to claim 5, characterized in that: The viscosity of alkoxy-terminated polysiloxane at 25°C is 40~80Pa•s; the viscosity of dimethyl silicone oil at 25°C is 0.15~0.35Pa•s.

7. A method for preparing the dealcoholized transparent adhesive according to claim 6, characterized in that: The steps include: S1. Add alkoxy-terminated polysiloxane, dimethyl silicone oil and crosslinking agent into a high-speed disperser and stir for 30-40 minutes under negative pressure; S2, add hydrophobic fumed silica and disperse for 20 minutes, and continue stirring under negative pressure for 20 minutes; S3, add polyalkoxy aminosilane coupling agent and catalyst, stir for 30-40 minutes under negative pressure to obtain.

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