Amine-terminated liquid nitrile rubber, its manufacturing method, and silicon-containing amine-terminated liquid nitrile rubber

Abstract

The present invention relates to the technical field of nitrile rubber, specifically to amine-terminated liquid nitrile rubber, a method for producing the same, and silicon-containing amine-terminated liquid nitrile rubber. The method includes the following steps: (1) performing an amino-protection reaction using a compound containing amino and hydroxy groups with an amino-protecting agent to obtain an amino-protected product; (2) performing an acid chlorination reaction using a carboxyl-terminated liquid nitrile rubber with an acid chlorination reagent to obtain an acid chlorination product; (3) performing a substitution reaction between the amino-protected product and the acid chlorination product to obtain a substitution product; and (4) performing an amino deprotection reaction with the substitution product to obtain the amine-terminated liquid nitrile rubber. The method for producing amine-terminated liquid nitrile rubber according to the present invention is easy to operate and has a clear reaction mechanism. The modified liquid nitrile rubber has promising future potential for functionalization and applications, making it suitable for industrial widespread use.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of Chinese Patent Application No. 202310843391.2, filed on July 11, 2023, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to the technical field of nitrile rubber, and more particularly to an amine-terminated liquid nitrile rubber, a method for producing the same, and a silicon-containing amine-terminated liquid nitrile rubber. [Background technology]

[0003] Amine-terminated liquid nitrile rubber, simply known as ATBN, refers to a liquid nitrile polymer containing an amino group (-NH2) at the chain end. Introducing amino groups into liquid nitrile rubber improves its adhesive properties, low-temperature resistance, electrical insulation, and other properties, making it suitable for use in high-quality adhesives, sealants, corrosion-resistant coatings, and water-soluble electrophoretic coatings, making it widely applicable to the defense industry, high-tech ships, and other fields. Meanwhile, the introduction of amino groups also activates nitrile rubber, potentially improving its performance and expanding its range of applications.

[0004] However, currently, China does not have the manufacturing technology related to amine-terminated liquid nitrile rubber, and amine-terminated liquid nitrile rubber is mainly dependent on imports. Therefore, there is an urgent need to provide a manufacturing method for amine-terminated liquid nitrile rubber and silicon-containing amine-terminated liquid nitrile rubber. Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide an amine-terminated liquid nitrile rubber, a method for producing the same, and a silicon-containing amine-terminated liquid nitrile rubber, in order to solve the problem of the lack of a method for producing amine-terminated liquid nitrile rubber in China. [Means for solving the problem]

[0006] In order to achieve the above object, the first aspect of the present invention comprises: Step (1) of carrying out an amino group protection reaction using a compound containing an amino group and a hydroxy group and an amino group protecting agent in the presence of a catalyst to obtain an amino group protected product; Step (2) of carrying out an acid chlorination reaction using the carboxyl group-terminated liquid nitrile rubber and an acid chlorination reagent to obtain an acid chlorination product; Step (3) of subjecting the amino group-protected product and the acid chloride-converted product to a substitution reaction to obtain a substitution product; and (4) subjecting the substitution product to an amino group deprotection reaction to obtain an amine-terminated liquid nitrile rubber.

[0007] A second aspect of the present invention provides an amine-terminated liquid nitrile rubber produced by the method according to the first aspect of the present invention.

[0008] A third aspect of the present invention provides a silicon-containing amine-terminated liquid nitrile rubber, which is a modified carboxy-terminated liquid nitrile rubber, in which —OH in at least a part of the carboxy terminal groups in the modified carboxy-terminated liquid nitrile rubber is substituted with a group represented by formula 1. [ka] wherein R1 and R2 are each independently selected from a hydroxy group and / or an alkyl group, and R3 is selected from an alkylene group. [Effects of the Invention]

[0009] According to the above technical solution, the present invention provides a method for producing amine-terminated liquid nitrile rubber, first protecting the amino group of a compound containing an amino group and a hydroxy group, then using carboxy-terminated liquid nitrile rubber as a starting material, introducing chlorine through an acid chlorination reaction, and utilizing a substitution reaction between the chlorine and the hydroxy group to introduce the protected amino group onto the liquid nitrile rubber, and then deaminating the protected amino group, thereby amminating the end groups of the liquid nitrile rubber. The method for producing amine-terminated liquid nitrile rubber according to the present invention is easy to operate and has a clear reaction mechanism, and the liquid nitrile rubber has promising future potential for functionalization modification and use, making it suitable for industrial widespread use.

[0010] The amine-terminated liquid nitrile rubber of the present invention has a viscosity at 27°C of 170 to 240 Pa·s, an amine value of 40 to 60 mgKOH / g, a free amine content of less than 4%, a number average molecular weight of 3500 to 4500 g / mol, a glass transition temperature of less than -45°C, and good aging resistance, ozone resistance, physiological inertness, and high and low temperature resistance.

[0011] The silicon-containing amine-terminated liquid nitrile rubber of the present invention has an amine value of 50 to 60 mgKOH / g, a glass transition temperature of less than -55°C, and is excellent in aging resistance, ozone resistance, physiological inertness, and high and low temperature resistance. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a hydrogen nuclear magnetic spectrum of the silicon-containing amine group-terminated liquid nitrile rubber obtained in Example 2. DETAILED DESCRIPTION OF THE INVENTION

[0013] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. With respect to numerical ranges, the endpoints of each range, the endpoints of each range and individual dot values, and the individual dot values ​​can be combined to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0014] A first aspect of the present invention is Step (1) of carrying out an amino group protection reaction using a compound containing an amino group and a hydroxy group and an amino group protecting agent in the presence of a catalyst to obtain an amino group protected product; Step (2) of carrying out an acid chlorination reaction using the carboxyl group-terminated liquid nitrile rubber and an acid chlorination reagent to obtain an acid chlorination product; Step (3) of subjecting the amino group-protected product and the acid chloride-converted product to a substitution reaction to obtain a substitution product; and (4) performing an amino group deprotection reaction on the substitution product and a deprotecting agent to obtain an amine-terminated liquid nitrile rubber.

[0015] In step (1), The present invention aims to introduce an amino group (-NH2) into nitrile rubber, activate the end groups of the nitrile rubber, and improve the activity of the nitrile rubber. In the present invention, the compound containing an amino group and a hydroxy group is not particularly limited, and any compound that can achieve the object of the present invention according to the production method of the present invention can be used in the present invention. For example, the compound containing an amino group and a hydroxy group can be a substance having the general formula NH2-R-OH, where R is a substituted or unsubstituted alkyl group, preferably a substituted or unsubstituted C2-C 20 R is an alkyl group, or R comprises a carbon skeleton containing groups in the carbon chain such as ketone groups, carbonyl groups, carboxy groups, ester groups, cyano groups, aryl groups, silicon groups, silyloxy groups, carbon-carbon double bonds, carbon-carbon triple bonds, etc.

[0016] In one embodiment of the present invention, the compound containing an amino group and a hydroxy group is 2-hydroxyethylamine (NH2-CH2-CH2-OH), p-hydroxyphenylethylamine ( [ka] ), 2-(3,4-dihydroxyphenyl)ethylamine ( [ka] ), 2-amino-1-phenylethanol ( [ka] ), and aminosilane coupling agent hydrolysis products.

[0017] In the present invention, the compound containing an amino group and a hydroxy group may be a commercially available product or may be synthesized according to a known method, and is not particularly limited in the present invention.

[0018] In one embodiment of the present invention, the aminosilane coupling agent hydrolysis product is obtained by subjecting an aminosilane coupling agent to a hydrolysis reaction, and the aminosilane coupling agent is one or more selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, (3-aminopropyl)dimethylethoxysilane, and 3-aminopropylmethyldiethoxysilane.

[0019] In the present invention, the aminosilane coupling agent contains a siloxanyl group, and the siloxanyl group reacts with water to remove the alkyl group and introduce a hydroxy group, thereby forming a compound having both an amino group and a hydroxy group.

[0020] In one embodiment of the present invention, the method for producing the aminosilane coupling agent hydrolysis product includes mixing an aminosilane coupling agent with water, preferably deionized water, in a volume ratio of 1:2 to 6, reacting the mixture at 40 to 80°C, preferably 50 to 70°C, for 0.5 to 3 hours, and distilling the mixture under reduced pressure when the solution becomes colorless and transparent to obtain the aminosilane coupling agent hydrolysis product.

[0021] In one embodiment of the present invention, the amino group protecting agent is one or more selected from a tert-butoxycarbonyl compound, a benzyloxycarboxy compound, a 2-biphenyl-2-propoxycarbonyl compound, a phthalimide compound, a trityl compound, a formyl compound, and a trifluoroacetyl compound, preferably a tert-butoxycarbonyl compound, and more preferably di-tert-butyl dicarbonate.

[0022] The reaction conditions vary depending on the amino group-protecting agent. In the present invention, there are no particular limitations on the operating conditions for the amino group-protecting reaction, and known reaction conditions can be selected depending on the amino group-protecting agent used to carry out the amino group-protecting reaction. In the present invention, the amino group-protecting reaction will be described using di-tert-butyl dicarbonate as an example of the amino group-protecting agent, but other types of amino group-protecting agents will not be described in detail.

[0023] In one embodiment of the present invention, when the amino group protecting agent is di-tert-butyl dicarbonate, the operating conditions for the amino group protecting reaction are as follows: The amino group protection reaction is carried out in solvent I, where solvent I is one or more selected from the group consisting of methanol, acetone, and tetrahydrofuran.

[0024] Preferably, the amount of the solvent I used is 4 to 15 g, and more preferably 6 to 10 g, per 1 g of the compound containing an amino group and a hydroxy group.

[0025] Preferably, the catalyst is one or more selected from triethylamine, sodium carbonate, sodium bicarbonate, sodium hydroxide.

[0026] Preferably, the mass ratio of the compound containing an amino group and a hydroxy group, the amino group protecting agent, and the catalyst is 1:1-2.5:0.5-2, and more preferably 1:1-1.5:1-1.5.

[0027] Preferably, the reaction temperature of the amino group protection reaction is room temperature, and the reaction time of the amino group protection reaction is 10 to 20 hours, preferably 15 to 16 hours. Room temperature has the well-known meaning, and may be, for example, 20 to 35°C.

[0028] In the present invention, first, the compound containing an amino group and a hydroxy group and the amino group-protecting agent are each dissolved in solvent I, and then the solution containing the amino group-protecting agent is added dropwise to the solution of the compound containing an amino group and a hydroxy group at room temperature. After the addition is completed, the reaction time is recorded.

[0029] Preferably, after the amino group protection reaction is completed, the reaction solution in which the amino group protection reaction is completed is distilled under reduced pressure to remove solvent I, and then water is added, followed by extraction with an extractant, and the extract is rotary evaporated to obtain the amino group protected product, wherein the extractant is selected from dichloromethane and / or chloroform.

[0030] In step (2), In one embodiment of the present invention, the acid chloridation reagent is one or more selected from thionyl chloride, phosphorus pentachloride, phosphorus trichloride, phosphorus oxychloride, preferably thionyl chloride.

[0031] In one embodiment of the present invention, the ratio of the amount of the carboxyl group-terminated liquid nitrile rubber to the amount of the acid chloride reagent used is 1 g: 30 to 70 mL, and preferably 1 g: 45 to 55 mL.

[0032] In one embodiment of the present invention, the acid chlorination reaction is carried out in solvent II, wherein solvent II is one or more selected from toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene.

[0033] In one embodiment of the present invention, the amount of the solvent II used is 1 to 10 mL, preferably 2.5 to 5 mL, per 1 g of the carboxyl group-terminated liquid nitrile rubber.

[0034] In the present invention, in order to improve the effect of mixing the carboxyl-terminated liquid nitrile rubber and the acid chloride reagent in solvent II, preferably, first the carboxyl-terminated liquid nitrile rubber is dispersed in solvent II, and then the acid chloride reagent is added to said solvent II, treated under ultrasonic conditions for 0.5 to 2 hours, and then heated to react.

[0035] In one embodiment of the present invention, the acid chlorination reaction is carried out under inert gas protection. In the present invention, the inert gas refers to a gas that does not react with any of the substances in the acid chlorination reaction, and for example, the inert gas may be nitrogen gas.

[0036] In one embodiment of the present invention, the reaction temperature of the acid chlorination reaction is 60 to 90°C, preferably 70 to 80°C, and the reaction time of the acid chlorination reaction is 8 to 20 hours, preferably 12 to 15 hours.

[0037] In one embodiment of the present invention, after the acid chlorination reaction is completed, solvent II is added again to the reaction solution in which the acid chlorination reaction is completed, i.e., the obtained reaction product, at room temperature, and the mixture is distilled, preferably under reduced pressure, thereby removing solvent II and unreacted acid chlorination reagent and obtaining the acid chlorination product.

[0038] In the present invention, the reason for adding solvent II again is to dissolve the acid chloride product produced by the reaction. The volume ratio of the amount of solvent II added again to the amount of solvent II added previously is 1:0.5 to 1.5, preferably 1:0.9 to 1.1.

[0039] In step (3), In one embodiment of the present invention, the mass ratio of the acid chloride product to the amino group-protected product is 1:1 to 2.5, preferably 1:1.5 to 2.0.

[0040] In one embodiment of the present invention, the substitution reaction is carried out in a solvent III, wherein the solvent III is one or more selected from dichloromethane, chloroform, dichloroethane, trichloroethane.

[0041] In one embodiment of the present invention, the amount of the solvent III used is 2 to 10 g, preferably 5 to 6 g, per 1 g of the acid chloride product.

[0042] In one embodiment of the present invention, the substitution reaction includes first dissolving the acid chloride product in the solvent III, then adding the amino group-protected product dropwise, and then reacting at room temperature for 6 to 18 hours, preferably 8 to 12 hours.

[0043] In one embodiment of the present invention, the dropwise addition is carried out at 0 to 10° C., preferably 0 to 5° C. In the present invention, the dropwise addition is carried out under ice bath conditions, more preferably while stirring in an ice bath.

[0044] In one embodiment of the present invention, after the substitution reaction is completed, the substitution reaction product, which is the reaction solution after the substitution reaction is completed, is first distilled under reduced pressure to remove solvent III, and then a purification reagent is added, followed by rotary evaporation and vacuum drying to obtain the substitution product.

[0045] In the present invention, the purification reagent is one or more of n-hexane, n-heptane, and n-octane, and the amount of the purification reagent added is 10 to 20 g per 1 g of the amino group-protected product.

[0046] In step (4), In the present invention, the amino group deprotection reaction will be described using the case where the amino group protecting agent is di-tert-butyl dicarbonate as an example. The amino group deprotection reactions corresponding to the remaining amino group protecting agents can be carried out by known methods, but will not be described in detail in the present invention.

[0047] In one embodiment of the present invention, when the amino group protecting agent is di-tert-butyl dicarbonate, the deprotecting agent is one or more selected from trifluoroacetic acid and / or dioxane hydrochloric acid solution, preferably trifluoroacetic acid.

[0048] In one embodiment of the present invention, the deamination reaction is carried out in solvent IV, wherein the solvent IV is one or more selected from dichloromethane, chloroform, dichloroethane, trichloroethane, and dimethylformamide.

[0049] In one embodiment of the present invention, the mass ratio of the substitution product to the deprotecting agent is 1:0.3-1, preferably 1:0.4-0.6, and the mass ratio of the substitution product to solvent IV is 1:4-10, preferably 1:6-8.

[0050] In one embodiment of the present invention, the reaction temperature of the amino group deprotection reaction is room temperature, and the reaction time of the amino group deprotection reaction is 0.2 to 2.5 hours, preferably 0.5 to 1 hour.

[0051] A second aspect of the present invention provides an amine-terminated liquid nitrile rubber produced by the method according to the first aspect of the present invention.

[0052] In the amine group-terminated liquid nitrile rubber produced by the method according to the first aspect of the present invention, at least a part of —OH of the carboxyl group terminal groups in the carboxyl group-terminated liquid nitrile rubber is substituted with an amino-containing group derived from a compound containing an amino group and a hydroxy group, and the structure of the substituted amine group-terminated liquid nitrile rubber may be represented by Formula 1-1 to Formula 1-4. [ka]

[0053] In the present invention, formulas 1-1 to 1-4 are merely illustrative, and the structure of the amine group-terminated liquid nitrile rubber after substitution does not necessarily have to be linked in the order of the general formula, and x, y, and z are each independently any integer selected from 5 to 1000.

[0054] In one embodiment of the present invention, the amine group-terminated liquid nitrile rubber has an amine value of 40 to 60 mg KOH / g, a free amine content of less than 4%, a number average molecular weight of 3500 to 4500 g / mol, a viscosity at 27°C of 170 to 240 Pa s, and a glass transition temperature of less than -45°C.

[0055] A third aspect of the present invention provides a silicon-containing amine-terminated liquid nitrile rubber, wherein the silicon-containing amine-terminated liquid nitrile rubber is a modified carboxy-terminated liquid nitrile rubber, and at least a part of —OH of the carboxy terminal groups in the modified carboxy-terminated liquid nitrile rubber is substituted with a group represented by formula 1. [ka] wherein R1 and R2 are each independently selected from a hydroxy group and / or an alkyl group, and R3 is selected from an alkylene group.

[0056] In one preferred embodiment of the present invention, the alkyl group is selected from straight or branched chain C1 to C5 alkyl groups, preferably one or more of methyl, ethyl, n-propyl.

[0057] In one preferred embodiment of the present invention, the alkylene group is selected from linear or branched C1 to C5 alkylene groups, preferably one or more of methylene, ethylene, propylene, butylene.

[0058] In one preferred embodiment of the present invention, the general formula of the structure in which at least a part of —OH of the carboxyl group terminal groups in the modified carboxyl group-terminated liquid nitrile rubber is substituted with a group represented by formula 1 is formula 1-1. [ka]

[0059] In one preferred embodiment of the present invention, the silicon-containing amine group-terminated liquid nitrile rubber has an amine value of 50 to 60 mgKOH / g, preferably 55 to 58 mgKOH / g.

[0060] In one preferred embodiment of the present invention, the silicon-containing amine-terminated liquid nitrile rubber has a free amine content of 2.9 to 3.8%, a number average molecular weight of 3800 to 4450 g / mol, a viscosity at 27°C of 185 to 235 Pa s, and a glass transition temperature of -58 to -56°C.

[0061] In one preferred embodiment of the present invention, the silicon-containing amine-terminated liquid nitrile rubber is produced by the method according to the first aspect of the present invention, wherein the compound containing an amino group and a hydroxy group is a hydrolysis product of an aminosilane coupling agent, the amino group protecting agent is di-tert-butyl dicarbonate, the acid chloridation reagent is thionyl chloride, and the deprotecting agent is trifluoroacetic acid.

[0062] The following examples further illustrate the present invention but are not intended to limit it.

[0063] The carboxyl-terminated liquid nitrile rubber was ANBR1300X16 manufactured by Lanzhou Petrochemical Co., Ltd., and had a number average molecular weight of 3830 g / mol. Example 1

[0064] (1) 10 mL of KH550 and 40 mL of deionized water were added to a three-necked flask equipped with a stirrer, and then the mixture was heated to 60°C and stirred for 1 hour to react. When the solution became colorless and transparent, the reaction was completed. After that, the solution was distilled under reduced pressure to remove the deionized water, and the hydrolysis product was obtained. 5 g of the above hydrolysis product and 6 g of triethylamine were added to 30 g of methanol and stirred thoroughly. Then, 18 g of a 30 wt % solution of di-tert-butyl dicarbonate in methanol was slowly added dropwise. After the addition was completed, the mixture was reacted at room temperature for 16 hours. After the reaction was completed, the methanol was removed by distillation under reduced pressure. The product was added to deionized water and extracted with dichloromethane to obtain an extract. The extract was then rotary evaporated to obtain the amino-protected product. (2) 2 g of carboxyl-terminated liquid nitrile rubber was dissolved in 5 mL of toluene and placed in a three-necked flask. Then, 90 mL of thionyl chloride was added and the mixture was subjected to ultrasonic treatment for 1 hour. The mixture was then heated to 70°C and subjected to an acid chloride reaction for 13 hours under nitrogen gas protection. After completion of the reaction, the mixture was cooled to room temperature, 90 mL of toluene was added, and the toluene and unreacted thionyl chloride were removed by distillation under reduced pressure to obtain an acid chloride product. (3) 1 g of the acid chloride product was dissolved in 5 g of dichloromethane, and 1.5 g of the amino group-protected product was slowly added dropwise at 0°C. After the addition was completed, the mixture was reacted at room temperature for 10 hours with magnetic stirring. After the reaction was completed, the mixture was distilled under reduced pressure to remove the dichloromethane, and 12.5 g of n-hexane was added for purification. The mixture was then rotary evaporated and dried in vacuo to obtain the substitution product. (4) 1 g of the above substitution product was dissolved in 7 g of dichloromethane, and 2.3 g of 25 wt % TFA solution was added. The mixture was reacted at room temperature for 0.5 hours. After the reaction was completed, the mixture was rotary evaporated and vacuum dried to obtain a silicon-containing amine-terminated liquid nitrile rubber. The reaction equations occurring in each step in Example 1 are as follows: Step (1) [ka] Step (2) [ka] Step (3) [ka] Step (4) [ka] Example 2

[0065] (1) 10 mL of KH550 and 35 mL of deionized water were added to a three-necked flask equipped with a stirrer, and then the mixture was heated to 50°C and stirred for 1.5 hours to react. When the solution became colorless and transparent, the reaction was completed. After that, the solution was distilled under reduced pressure to remove the deionized water, and the hydrolysis product was obtained. 5 g of the above hydrolysis product and 5 g of triethylamine were added to 30 g of methanol and stirred thoroughly. Then, 20 g of a 30 wt % solution of di-tert-butyl dicarbonate in methanol was slowly added dropwise. After the addition was completed, the mixture was reacted at room temperature for 16 hours. After the reaction was completed, the methanol was removed by distillation under reduced pressure. The product was added to deionized water and extracted with dichloromethane to obtain an extract. The extract was then rotary evaporated to obtain the amino-protected product. (2) 2 g of carboxyl-terminated liquid nitrile rubber was dissolved in 5 mL of toluene and placed in a three-necked flask. Then, 100 mL of thionyl chloride was added and the mixture was subjected to ultrasonic treatment for 1 hour. The mixture was then heated to 80°C and subjected to an acid chloride reaction for 14 hours under nitrogen gas protection. After completion of the reaction, the mixture was cooled to room temperature, 100 mL of toluene was added, and the toluene and unreacted thionyl chloride were removed by distillation under reduced pressure to obtain an acid chloride product. (3) 1 g of the acid chloride product was dissolved in 5 g of dichloromethane, and 2 g of the amino group-protected product was slowly added dropwise at 3°C. After the addition was completed, the mixture was reacted at room temperature for 12 hours with magnetic stirring. After the reaction was completed, the mixture was distilled under reduced pressure to remove the dichloromethane, and 12.5 g of n-hexane was added for purification. The mixture was then rotary evaporated and dried in vacuo to obtain the substituted product. (4) 1 g of the above substitution product was dissolved in 7 g of dichloromethane, and 2.0 g of 25 wt % TFA solution was added. The mixture was reacted at room temperature for 1 hour. After the reaction was completed, the mixture was rotary evaporated and vacuum dried to obtain a silicon-containing amine-terminated liquid nitrile rubber. Example 3

[0066] (1) 10 mL of KH550 and 20 mL of deionized water were added to a three-necked flask equipped with a stirrer, and then the mixture was heated to 40°C and stirred for 2 hours to react. After the solution became colorless and transparent and the reaction was completed, the solution was distilled under reduced pressure to remove the deionized water and obtain the hydrolysis product. 5 g of the above hydrolysis product and 3 g of triethylamine were added to 30 g of methanol and stirred thoroughly. Then, 30 g of a 30 wt % solution of di-tert-butyl dicarbonate in methanol was slowly added dropwise. After the addition was completed, the mixture was reacted at room temperature for 18 hours. After the reaction was completed, the methanol was removed by distillation under reduced pressure. The product was added to deionized water and extracted with dichloromethane to obtain an extract. The extract was then rotary evaporated to obtain the amino-protected product. (2) 2 g of carboxyl-terminated liquid nitrile rubber was dissolved in 5 mL of toluene and placed in a three-necked flask. Then, 120 mL of thionyl chloride was added and the mixture was subjected to ultrasonic treatment for 1 hour. The mixture was then heated to 65°C and subjected to an acid chloride reaction for 18 hours under nitrogen gas protection. After completion of the reaction, the mixture was cooled to room temperature, 120 mL of toluene was added, and the toluene and unreacted thionyl chloride were removed by distillation under reduced pressure to obtain an acid chloride product. (3) 1 g of the acid chloride product was dissolved in 5 g of dichloromethane, and 1 g of the amino group-protected product was slowly added dropwise at 5°C. After the addition was completed, the mixture was reacted at room temperature for 6 hours with magnetic stirring. After the reaction was completed, the mixture was distilled under reduced pressure to remove the dichloromethane, and 12.5 g of n-hexane was added for purification. The mixture was then rotary evaporated and dried in vacuo to obtain the substituted product. (4) 1 g of the above substitution product was dissolved in 7 g of dichloromethane, and 1.5 g of 25 wt % TFA solution was added. The mixture was reacted at room temperature for 1 hour. After the reaction was completed, the mixture was rotary evaporated and vacuum dried to obtain a silicon-containing amine-terminated liquid nitrile rubber. Example 4

[0067] (1) 10 mL of KH550 and 60 mL of deionized water were added to a three-necked flask equipped with a stirrer, and then the mixture was heated to 75°C and stirred for 0.5 hours to react. When the solution became colorless and transparent, the reaction was completed. After that, the solution was distilled under reduced pressure to remove the deionized water, and the hydrolysis product was obtained. 5 g of the above hydrolysis product and 8 g of triethylamine were added to 30 g of methanol and stirred thoroughly. Then, 35 g of a 30 wt % solution of di-tert-butyl dicarbonate in methanol was slowly added dropwise. After the addition was completed, the mixture was reacted at room temperature for 12 hours. After the reaction was completed, the methanol was removed by distillation under reduced pressure. The product was added to deionized water and extracted with dichloromethane to obtain an extract. The extract was then rotary evaporated to obtain the amino-protected product. (2) 2 g of carboxyl-terminated liquid nitrile rubber was dissolved in 5 mL of toluene and placed in a three-necked flask. Then, 60 mL of thionyl chloride was added and the mixture was subjected to ultrasonic treatment for 1 hour. The mixture was then heated to 85°C and subjected to an acid chloride reaction for 10 hours under nitrogen gas protection. After completion of the reaction, the mixture was cooled to room temperature, 60 mL of toluene was added, and the toluene and unreacted thionyl chloride were removed by distillation under reduced pressure to obtain an acid chloride product. (3) 1 g of the acid chloride product was dissolved in 5 g of dichloromethane, and 2.5 g of the amino group-protected product was slowly added dropwise at 0°C. After the addition was completed, the mixture was reacted at room temperature for 14 hours with magnetic stirring. After the reaction was completed, the mixture was distilled under reduced pressure to remove the dichloromethane, and 12.5 g of n-hexane was added for purification. The mixture was then rotary evaporated and dried in vacuo to obtain the substituted product. (4) 1 g of the above substitution product was dissolved in 7 g of dichloromethane, and 3.0 g of 25% TFA solution was added. The mixture was reacted at room temperature for 1.5 hours. After the reaction was completed, the mixture was rotary evaporated and vacuum dried to obtain a silicon-containing amine-terminated liquid nitrile rubber. Example 5

[0068] The procedure was the same as in Example 4, except that the hydrolysis in step (1) was omitted and the hydrolysis product was replaced with the same amount of 2-hydroxyethylamine. The resulting amine-terminated liquid nitrile rubber has the following general structure in which at least some of the —OH groups of the carboxyl terminal groups in the carboxyl-terminated liquid nitrile rubber have been replaced with groups containing amino groups: [ka] Example 6

[0069] The procedure was the same as in Example 4, except that the hydrolysis in step (1) was omitted and the hydrolysis product was replaced with the same amount of p-hydroxyphenylethylamine. The resulting amine-terminated liquid nitrile rubber has the following general structure in which at least some of the —OH groups of the carboxyl terminal groups in the carboxyl-terminated liquid nitrile rubber have been replaced with groups containing amino groups: [ka] Example 7

[0070] The procedure was the same as in Example 4, except that the hydrolysis in step (1) was omitted and the hydrolysis product was changed to the same amount of 2-amino-1-phenylethanol. The resulting amine-terminated liquid nitrile rubber has the following general structure in which at least some of the —OH groups of the carboxyl terminal groups in the carboxyl-terminated liquid nitrile rubber have been replaced with groups containing amino groups: [ka] Test Example 1

[0071] The silicon-containing amine-terminated liquid nitrile rubber obtained in Example 2 was subjected to nuclear magnetic measurement, and the test results are shown in FIG. As can be seen from the hydrogen nuclear magnetic spectrum of the modified liquid nitrile rubber in Figure 1, 1H-NMR (400 MHz, CDCl3) showed that the peak at δ 6.33 (a) was -OH and the peak at δ 1.43 (b) was -NH2. These two characteristic peaks demonstrated that this silicon-containing amine-terminated liquid nitrile rubber was successfully prepared. Test Example 2

[0072] The amine group-terminated liquid nitrile rubbers produced in Examples 1 to 7 were measured for their corresponding performance, and the measurement results are shown in Table 1. Here, the viscosity was measured using a rotational viscometer, the free amine number was measured according to GB / T 6365-2006, and the glass transition temperature was measured according to GB / T 29611-2013. Specifically, the carboxyl group conversion rate was determined by acid-base titration as follows. Equal masses of the raw carboxyl-terminated liquid nitrile rubber and the prepared amine-terminated liquid nitrile rubber were each immersed in 0.5% HCl for 30 minutes, filtered, washed several times with deionized water, and dried. Next, 1 g of each sample was taken, immersed in an iodine flask containing 250 mL of 0.1 M calcium acetate solution, and left on a shaker for 24 hours. 10 mL of the test solution was placed in an Erlenmeyer flask and titrated with 0.1 mol / L NaOH solution using cresol red and thymol blue as indicators. When the color changed from yellow to purple, the titration was stopped and the content was calculated. If the molar content of carboxyl groups in the raw carboxyl-terminated liquid nitrile rubber is n1 and the molar content of carboxyl groups in the prepared amine-terminated liquid nitrile rubber is n2, the carboxyl group conversion rate is (n1 - n2) / n1. Amine number is measured using the acid required to neutralize the sample and is expressed in milligrams of potassium hydroxide.

[0073] [Table 1]

[0074] As can be seen from Table 1, the carboxyl group conversion rate of the amine-terminated liquid nitrile rubbers prepared in Examples 1 to 7 was 75% or more, the amine value was 40 to 60 mg KOH / g, and the free amine was less than 4%, indicating that the liquid nitrile rubbers containing amino groups at the terminal groups were successfully prepared.

[0075] The amine-terminated liquid nitrile rubbers prepared in Examples 1 to 7 have viscosities in the range of 170 to 240 Pa·s, number-average molecular weights of 3500 to 4500 g / mol, and glass transition temperatures below −45°C. Liquid nitrile rubbers containing amine end groups have excellent fluidity and low-temperature resistance, and are expected to have future modifications and uses. In Examples 1 to 4, the silicon-containing amine-terminated liquid nitrile rubbers exhibited relatively good performance, with glass transition temperatures below −55° C. This is because the introduction of the silane-containing structure further improved the performance of the liquid nitrile rubber.

[0076] Within the scope of the technical concept of the present invention, the technical solution of the present invention can be easily modified in multiple ways, including combining each specific technical feature in any suitable manner. To avoid unnecessary repetition, various combinations of the present invention will not be described separately. However, these simple modifications and combinations should also be considered as the disclosure content of the present invention, and all fall within the protection scope of the present invention.

Claims

1. Step (1) of carrying out an amino group protection reaction using a compound containing an amino group and a hydroxy group and an amino group protecting agent in the presence of a catalyst to obtain an amino group protected product; Step (2) of carrying out an acid chlorination reaction using the carboxyl group-terminated liquid nitrile rubber and an acid chlorination reagent to obtain an acid chlorination product; Step (3) of subjecting the amino group-protected product and the acid chloride product to a substitution reaction to obtain a substitution product; and (4) performing an amino group deprotection reaction on the substitution product and a deprotecting agent to obtain an amine group-terminated liquid nitrile rubber.

2. The method according to claim 1, wherein the compound containing an amino group and a hydroxy group is one or more selected from the group consisting of 2-hydroxyethylamine, p-hydroxyphenylethylamine, 2-(3,4-dihydroxyphenyl)ethylamine, 2-amino-1-phenylethanol, and hydrolysis products of aminosilane coupling agents.

3. The method according to claim 2, wherein the aminosilane coupling agent hydrolysis product is obtained by subjecting an aminosilane coupling agent to a hydrolysis reaction, and the aminosilane coupling agent is one or more selected from the group consisting of 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, (3-aminopropyl)dimethylethoxysilane, and 3-aminopropylmethyldiethoxysilane.

4. The method according to claim 1, wherein the amino group protecting agent is one or more selected from the group consisting of tert-butoxycarbonyl compounds, benzyloxycarboxy compounds, 2-biphenyl-2-propoxycarbonyl compounds, phthalimide compounds, trityl compounds, formyl compounds, and trifluoroacetyl compounds.

5. The method according to claim 4, wherein the amino group protecting agent is a tert-butoxycarbonyl compound.

6. The method according to claim 5, wherein the amino group protecting agent is di-tert-butyl dicarbonate.

7. When the amino group protecting agent is di-tert-butyl dicarbonate, the operating conditions for the amino group protecting reaction are as follows: the amino group protection reaction is carried out in a solvent I, wherein the solvent I is one or more selected from the group consisting of methanol, acetone, and tetrahydrofuran; and / or the catalyst is one or more selected from the group consisting of triethylamine, sodium carbonate, sodium bicarbonate, and sodium hydroxide; and / or the mass ratio of the compound containing an amino group and a hydroxy group, the amino group protecting agent, and the catalyst is 1:1-2.5:0.5-2; and / or the reaction temperature of the amino group protection reaction is room temperature, and the reaction time of the amino group protection reaction is 10 to 20 hours.

8. the mass ratio of the compound containing an amino group and a hydroxy group, the amino group protecting agent, and the catalyst is 1:1 to 1.5:1 to 1.5; and / or the reaction time of the amino group protection reaction is 15 to 16 hours.

9. the acid chloridation reagent is one or more selected from thionyl chloride, phosphorus pentachloride, phosphorus trichloride, and phosphorus oxychloride; and / or the ratio of the amount of the carboxyl group-terminated liquid nitrile rubber to the amount of the acid chloride reagent used is 1 g:30 to 70 mL.

10. the acid chloridation reagent is thionyl chloride; And / or, the ratio of the amount of the carboxyl group-terminated liquid nitrile rubber to the amount of the acid chloride reagent used is 1 g:45 to 55 mL.

11. The acid chlorination reaction is carried out in a solvent II, wherein the solvent II is one or more selected from toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene; and / or the acid chlorination reaction is carried out under protection of an inert gas; and / or the reaction temperature of the acid chloride reaction is 60 to 90°C, and the reaction time of the acid chloride reaction is 8 to 20 hours; and / or, after completion of the acid chloride reaction, the solvent II is again added to the reaction product obtained at room temperature, followed by distillation to remove the solvent II and unreacted acid chloride reagent, thereby obtaining the acid chloride product.

12. the inert gas is nitrogen gas, and / or the reaction temperature of the acid chloride reaction is 70 to 80°C, and the reaction time of the acid chloride reaction is 12 to 15 hours; And / or the distillation is vacuum distillation, The production method of Claim 11.

13. the mass ratio of the acid chloride product to the amino group-protected product is 1:1 to 2.5; and / or the substitution reaction is carried out in a solvent III, wherein the solvent III is one or more selected from the group consisting of dichloromethane, chloroform, dichloroethane, and trichloroethane; and / or the substitution reaction comprises first dissolving the acid chloride product in the solvent III, then adding the amino group-protected product dropwise, and then reacting at room temperature for 6 to 18 hours; and / or the dropping is carried out at 0 to 10°C; and / or, after the substitution reaction is completed, first, the obtained substitution reaction product is distilled under reduced pressure to remove the solvent III, and then a purification reagent is added, followed by rotary evaporation and vacuum drying to obtain a substitution product; and / or the purification reagent is one or more of n-hexane, n-heptane, and n-octane, and the amount of the purification reagent added is 10 to 20 g per 1 g of the amino group-protected product.

14. the mass ratio of the acid chloride product to the amino group-protected product is 1:1.5 to 2; and / or the duration of the substitution reaction is 8 to 12 hours; And / or, the dropping temperature is 0 to 5°C, The manufacturing method according to claim 13.

15. the deprotecting agent is selected from trifluoroacetic acid and / or dioxane hydrochloric acid solution; and / or the deamination reaction is carried out in a solvent IV, wherein the solvent IV is one or more selected from the group consisting of dichloromethane, chloroform, dichloroethane, trichloroethane, and dimethylformamide; and / or the mass ratio of the substitution product to the deprotection agent is 1:0.3-1; and / or the method according to claim 1, wherein the temperature of the amino group deprotection reaction is room temperature, and the reaction time of the amino group deprotection reaction is 0.2 to 2.5 hours.

16. the deprotecting agent is trifluoroacetic acid; and / or the mass ratio of the substitution product to the deprotection agent is 1:0.4-0.6; and / or the method according to claim 15, wherein the temperature of the amino group deprotection reaction is room temperature, and the reaction time of the amino group deprotection reaction is 0.5 to 1 hour.

17. An amine-terminated liquid nitrile rubber produced by the method according to any one of claims 1 to 16.

18. A silicon-containing, amine-terminated liquid nitrile rubber, comprising: The silicon-containing, amine-terminated liquid nitrile rubber is a modified carboxy-terminated liquid nitrile rubber, wherein at least a part of —OH of the carboxy terminal groups in the modified carboxy-terminated liquid nitrile rubber is substituted with a group represented by formula 1. 【Chemistry 1】 (where R １ , and R ２ are each independently selected from a hydroxy group and / or an alkyl group; R ３ is selected from alkylene groups.

19. The alkyl group may be a straight or branched C １ ~C ５ The alkylene group is selected from a linear or branched C １ ~C ５ 20. The silicon-containing amine-terminated liquid nitrile rubber of claim 18, wherein the alkylene groups are selected from the group consisting of methyl, methyl, methyl ...

20. The silicon-containing, amine group-terminated liquid nitrile rubber according to claim 19, wherein the alkyl group is one or more types selected from methyl, ethyl, and n-propyl, and the alkylene group is one or more types selected from methylene, ethylene, propylene, and butylene.

21. The silicon-containing amine-terminated liquid nitrile rubber according to any one of claims 18 to 20, wherein the amine value of the amine-terminated liquid nitrile rubber is 50 to 60 mg KOH / g.

22. The silicon-containing amine-terminated liquid nitrile rubber according to claim 21, wherein the amine value of the amine-terminated liquid nitrile rubber is 55 to 58 mg KOH / g.

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