A fluorine-containing high-strength and high-temperature resistant polyurea material and its synthesis method and application

Abstract

A fluorine-containing high-strength and high-temperature resistant polyurea material and its synthesis method and application belong to the technical field of polyurea materials. The raw materials included in the fluorine-containing high-strength and high-temperature resistant polyurea material are polyurea raw materials and tetrafluorobutanediol; in terms of mass ratio, polyurea material: tetrafluorobutanediol = 2: (1-1.4). By adding tetrafluorobutanediol as a chain extender to the polyurea component, the performance of the polyurea is regulated. The fluorine-containing high-strength and high-temperature resistant polyurea material prepared by this method solves the problem that ordinary polyurea materials cannot meet the requirements of use in high-temperature environments, and improves its bonding strength, shear strength and other properties to a certain extent. The fluorine-containing high-strength and high-temperature resistant polyurea material has a simple preparation process and excellent material properties. It has achieved multiple uses of one material to a certain extent and is expected to be applied to a wider range of technical fields.

Description

Technical Field

[0001] The invention relates to the technical field of polyurea materials, and in particular to a fluorine-containing high-strength and high-temperature resistant polyurea material and a synthesis method and application thereof. Background Art

[0002] With the rapid development of science and technology, polymer materials are receiving more and more attention. Polyurea material is a high-performance polymer material made by polymer reaction. Nowadays, it has been widely used in aerospace, automobile manufacturing, construction engineering and electronic equipment, etc., which have high requirements for comprehensive material performance.

[0003] Although polyurea materials have certain thermal stability at 200℃~300℃, the high temperature stability and comprehensive performance of polyurea are often greatly reduced in high temperature application environments such as engineering manufacturing and construction. This is because the reason why polyurea materials have high high temperature resistance is closely related to their material structure. Polyurea is a material made by the reaction of isocyanate and polyols such as polyether or polyester. The hydroxyl group in the polyol molecule and the NCO group in the isocyanate can undergo condensation reaction to form the main chain and side chain of the polyurea material. The thermal stability of polyurea materials is also closely related to their molecular structure. As the content of hard segments inside the group increases, the decomposition temperature of the polyurea material decreases, and the thermal stability also decreases. If the content of hard segments inside the group is reduced, the comprehensive mechanical properties of the polyurea material will decrease, indicating that thermal stability and comprehensive mechanical properties are two contradictory relationships of "one rises and the other falls" in polyurea materials.

[0004] In summary, developing a synthesis process that can ensure that polyurea coatings have good comprehensive performance while maintaining high temperature stability has become an urgent problem to be solved. Summary of the invention

[0005] Based on the problems faced by the above-mentioned application fields, the present invention proposes a fluorine-containing high-strength and high-temperature resistant polyurea material and its synthesis method and application. By adding a suitable proportion of tetrafluorobutanediol as a chain extender to the polyurea component, the performance of the polyurea is regulated. The fluorine-containing high-strength and high-temperature resistant polyurea material prepared by this method solves the problem that ordinary polyurea materials cannot meet the requirements of use in high-temperature environments, and improves its bonding strength, shear strength and other properties to a certain extent. The fluorine-containing high-strength and high-temperature resistant polyurea material has a simple preparation process and excellent material properties. It has achieved multiple uses of one material to a certain extent and is expected to be applied to a wider range of technical fields.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The fluorine-containing high-strength and high-temperature resistant polyurea material of the present invention comprises raw materials of polyurea and tetrafluorobutanediol; in terms of mass ratio, the raw material of polyurea:tetrafluorobutanediol=2:(1-1.4).

[0008] The fluorine-containing high-strength and high-temperature resistant polyurea material has a tensile strength range of 32MPa to 54MPa, a breaking elongation range of 714% to 1030%, a bonding strength of 11 to 16MPa, and a shear strength of 22 to 30MPa. The adhesion to the hydrophilic polymer substrate can reach 8 to 11MPa, and the temperature at which the mass loss rate is 5% is 480°C to 570°C.

[0009] The raw materials of the polyurea include isocyanate, macromolecular diamine and maleic anhydride; in molar ratio, isocyanate, macromolecular diamine: maleic anhydride = 1: (2-3): (2-3), preferably 1: 2.6: 2.3.

[0010] A method for synthesizing a fluorine-containing high-strength and high-temperature resistant polyurea material of the present invention comprises the following steps:

[0011] S1: weighing the raw materials of polyurea according to the ratio, vacuum dehydrating them respectively, cooling them to room temperature, and obtaining dehydrated isocyanate, dehydrated macromolecular diamine, and dehydrated maleic anhydride respectively;

[0012] In the above-mentioned S1, the temperature of vacuum dehydration is 100-105° C., and the dehydration time is more than 1 hour.

[0013] S2: Under an inert gas, the dehydrated isocyanate and the dehydrated macromolecular diamine are mixed, stirred evenly, and heated to 85-90° C. for prepolymerization for 2-3 hours to obtain prepolymer A;

[0014] In the S2, the inert gas is preferably one of argon, helium and nitrogen; helium is most preferred, which can play a protective role, reduce unnecessary reactions and isolate moisture in the air.

[0015] S3: stirring the dehydrated maleic anhydride and prepolymer A for 20 to 30 minutes to obtain an oligomer; wherein the stirring rate is 500 to 700 rpm;

[0016] In the S3, the molar ratio of maleic anhydride: prepolymer A = (2-3): 1; preferably 2.3:1.

[0017] S4: cooling the oligomer to room temperature, stirring at 0°C for 10 to 20 minutes at a stirring rate of 500 to 700 rpm to obtain a low-temperature stirred oligomer;

[0018] S5: subjecting tetrafluorobutanediol and the oligomer after low-temperature stirring to a chain extension reaction at 25-35° C. to obtain an oligomer after chain extension; wherein the stirring rate of the chain extension reaction is 500-700 rpm until the stirring is uniform;

[0019] In the S5, the molar ratio of tetrafluorobutanediol to low temperature stirred oligomer is 1:2.

[0020] S6: After the chain extension is completed, the oligomer is uniformly stirred for 30 to 60 minutes, and then cured to obtain a fluorine-containing high-strength and high-temperature resistant polyurea material.

[0021] In the above-mentioned S6, the curing temperature is 65-85° C. and the curing time is 24-72 hours.

[0022] The invention discloses an application of a fluorine-containing high-strength and high-temperature resistant polyurea material for use as a protective coating.

[0023] Furthermore, the fluorine-containing high-strength and high-temperature resistant polyurea material may be added with one or more of diluents, fillers, coupling agents, dispersants, pigments, defoamers or antioxidants according to the specific use and functional characteristics of the protective coating.

[0024] The diluent includes but is not limited to one or more of ethyl acetate (EAc), butyl acetate (BAc), propylene glycol methyl ether acetate (PMA), and ethyl 3-ethoxypropionate (EEP). The amount of the diluent used can account for 5-30% of the total weight of the prepolymer A component, preferably 10-15%.

[0025] The filler is selected from one or more of calcium carbonate, talcum powder, titanium dioxide, silicon powder, and barium sulfate. The total amount of the filler used can account for 10-50% of the total weight of the prepolymer component A, preferably 15-30%.

[0026] The diluent and / or filler is added after the dehydrated isocyanate and the dehydrated macromolecular diamine are evenly mixed in the above synthesis step S2.

[0027] The coupling agent is a silane coupling agent, more preferably one or more of KH550, KH560, and KH602. The amount of the coupling agent used is 0.1% to 1% of the total weight of the filler in the prepolymer component A, preferably 0.1 to 0.5%.

[0028] The dispersant is selected from one or more of BYK110, BYK163 and BYK180. The amount of the dispersant used is determined according to the supplier's recommendation.

[0029] The coupling agent and / or dispersant is added in the above synthesis step S5, that is, after tetrafluorobutanediol and the oligomer stirred at low temperature are uniformly mixed, they are added before the chain extension reaction.

[0030] The pigment is selected from one or more of carbon black, titanium dioxide, iron yellow, iron red, and phthalocyanine blue. The amount of the pigment used is determined according to the color requirements of the coating.

[0031] The defoamer is selected from one or more of BYK066N and BYK085. The amount of the defoamer used is determined according to the supplier's recommendation.

[0032] The antioxidant is selected from one or more of BASF1010, BASF B225 and BASF1330. The amount of antioxidant used is determined according to the supplier's recommendation.

[0033] One or more of the pigment, defoamer and antioxidant are added in the above-mentioned synthesis step S6, that is, the oligomer after chain extension is uniformly stirred for 30 to 60 minutes before being added.

[0034] Compared with the existing polyurea coatings and silicone rubber / polyurea coatings, the fluorine-containing high-strength and high-temperature resistant polyurea material of the present invention and its synthesis method and application have the following advantages:

[0035] 1. The fluorine-containing high-strength and high-temperature resistant polyurea material of the present invention greatly enhances the high-temperature resistance of the polyurea material, and while maintaining the high-temperature resistance, it also provides a bonding strength of 15.03MPa and a shear strength of 29.32MPa. In addition, the dosage of the added modifier can be adjusted, and the prepared fluorine-containing high-strength and high-temperature resistant polyurea material can be applied to more application scenarios.

[0036] 2. The fluorine-containing high-strength and high-temperature resistant polyurea material of the present invention significantly improves the high-temperature stability of the polyurea coating, and the comprehensive performance of the material is also significantly improved compared with the known polyurea coating and silicone rubber / polyurea coating.

[0037] 3. The fluorine-containing high-strength and high-temperature resistant polyurea material of the present invention can be applied to thermal barrier coatings of aircraft and ships, and has a low weight, thereby achieving the purpose of lightweight assembly.

[0038] 4. The chain extender tetrafluorobutanediol used in the present invention, also known as 2,2,3,3-tetrafluoro-1,4-butanediol, has good stability and high temperature resistance due to its unique chemical structure. Adding it to the polyurea component as a chain extender can ensure that the modified polyurea coating has good high temperature stability while maintaining its original high mechanical properties. This is because the tetrafluorobutanediol molecule has a relatively compact and symmetrical structure, so that it can have high bonding strength and shear strength while maintaining high temperature stability.

[0039] 5. In the synthesis process of fluorinated polyurea, the primary amine is converted into secondary amine by the reaction of maleate and amino group, the reactivity of -NH and -NCO is reduced, and the polyurea coating obtained therefrom has good mechanical properties. In addition, fluorine atoms have strong electronegativity, and the binding energy of carbon-fluorine bonds is much higher than that of carbon-hydrogen bonds, which can well protect the main chain of macromolecules, improve the performance of materials and the material properties possessed by fluorine atoms. Fluorinated polyurea can be prepared as a substituent in the side chain of polyurea, and the value-added related thereto can be detected. The introduction of such fluorine-containing groups improves the high temperature resistance of non-empty polyurea, and also gives the material other excellent properties, such as good adhesion, impact resistance, ductility, etc. On the one hand, it is because the fluorine element is the element with the strongest electronegativity, and can form very stable chemical bonds, especially CF bonds, with atoms such as carbon, hydrogen, and nitrogen. On the other hand, tetrafluorobutanediol is selected because the fluorine atoms in its molecules can increase the thermal stability of polyurea materials, because the molecular structure of fluoride has a strong anti-pyrolysis effect to high temperature, which can reduce the breakage and degradation of molecular chains. Secondly, the molecule of tetrafluorobutanediol has a relatively compact and symmetrical structure, which can form a stable cross-linked structure in polyurea, thereby improving the thermal stability and high temperature resistance of the material. Other fluorinated compounds, due to differences in molecular structure, may not be able to effectively improve the high temperature resistance of polyurea like tetrafluorobutanediol. The most important thing is that the fluorinated groups in tetrafluorobutanediol are well compatible with the groups of polyurea, allowing them to be evenly distributed in the molecular chain of polyurea, thereby effectively improving the thermal stability and heat resistance of the material. Other fluorinated compounds may not be as evenly dispersed as tetrafluorobutanediol or have poor dispersion effects due to differences in molecular structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the synthesis process of the fluorine-containing high-strength and high-temperature resistant polyurea material of the present invention;

[0041] Figure 2 This is a graph showing the high-temperature performance of fluorine-containing high-strength and high-temperature resistant polyurea material as the amount of tetrafluorobutanediol added changes;

[0042] Figure 3 This is a graph showing the change in tensile strength of fluorine-containing high-strength and high-temperature resistant polyurea material with the amount of tetrafluorobutanediol added;

[0043] Figure 4 This is a graph showing the adhesion of fluorinated high-strength and high-temperature resistant polyurea material as the amount of tetrafluorobutanediol added changes. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with embodiments.

[0045] In the following examples, the high temperature resistance and some mechanical properties of the prepared fluorine-containing high-strength and high temperature resistant polyurea material are tested, including the following testing work:

[0046] (1) The prepared fluorine-containing high-strength and high-temperature resistant polyurea material needs to be cured at 25 to 35° C. for 1 to 3 days to achieve complete curing;

[0047] (2) Mechanical properties tests were performed using a general tensile testing machine (GX-SF001) from Shenzhen Shared Instruments Co., Ltd. The test was carried out at a strain rate of 50 mm / min, and at least four samples were tested according to ISO 37-2005. The tensile specimen was 35 mm long, 2 mm wide in the middle, 1 mm thick, and had a gauge length of 10 mm;

[0048] (3) Thermogravimetric analyzer TGA-209A manufactured by Beijing AVIC Times Instruments Co., Ltd. was used for the test. The mass of material put into each test was 0.1 g, the reaction temperature range was set at 400-600°C, and the temperature gradient was 10°C.

[0049] In the following examples, the adhesion test of the prepared fluorine-containing high-strength and high-temperature resistant polyurea material includes the following test work:

[0050] The adhesion test was performed using a pull-off adhesion tester from DeFelsko, USA ( AT). At least four samples were tested according to ASTM D4541. Before testing, ensure that the coating surface on the substrate is clean and free of contamination; stick a suitable size ingot on the coating surface with a suitable adhesive and ensure that the adhesive is fully cured; record the maximum tensile force when the coating is separated, and observe and record the separation mode (such as coating self-destruction, coating and substrate interface separation, substrate destruction, etc.).

[0051] Example 1

[0052] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which is shown in Figure 1 , including the following steps:

[0053] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 under vacuum at 100° C. for 1 h, then take them out and cool them to room temperature for later use;

[0054] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0055] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed for 30 min in a reaction kettle to obtain an oligomer;

[0056] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0057] (5) adding 0.5 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C. The reaction is mechanically stirred for 10 to 15 minutes;

[0058] (6) After the chain extension is completed, the oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0059] The tensile strength of the prepared fluorine-containing high-temperature resistant polyurea composite material is 53.85MPa, the elongation at break is in the range of 982%, the adhesion to the hydrophilic polymer substrate can reach 10.7MPa, and the temperature at which the mass loss rate is 5% is 568°C.

[0060] Example 2

[0061] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which comprises the following steps:

[0062] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0063] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0064] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed in a reaction kettle for 30 min to obtain an oligomer;

[0065] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0066] (5) adding 0.1 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C. The reaction is mechanically stirred for 10 to 15 minutes;

[0067] (6) The chain-extended oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0068] The tensile strength of the prepared fluorine-containing high-temperature resistant polyurea composite material is 38.65MPa, the elongation at break ranges from 767%, the adhesion to the hydrophilic polymer substrate can reach 8.43MPa, and the temperature at which the mass loss rate is 5% is 483°C.

[0069] Example 3

[0070] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which comprises the following steps:

[0071] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0072] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0073] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed in a reaction kettle for 30 min to obtain an oligomer;

[0074] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0075] (5) adding 0.2 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C., with mechanical stirring for 10 to 15 minutes;

[0076] (6) The chain-extended oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0077] The tensile strength of the prepared fluorine-containing high-temperature resistant polyurea composite material is 43.37 MPa, the elongation at break ranges from 863%, the adhesion to the hydrophilic polymer substrate can reach 8.88 MPa, and the temperature at which the mass loss rate is 5% is 493°C.

[0078] Example 4

[0079] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which comprises the following steps:

[0080] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0081] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0082] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed in a reaction kettle for 30 min to obtain an oligomer;

[0083] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0084] (5) adding 0.3 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C. The reaction is mechanically stirred for 10 to 15 minutes;

[0085] (6) After the chain extension is completed, the oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0086] The prepared fluorine-containing high-temperature resistant polyurea composite material has a tensile strength of 48.93 MPa, an elongation at break of 1029%, an adhesion to a hydrophilic polymer substrate of up to 9.15 MPa, and a temperature of 521°C when the mass loss rate is 5%.

[0087] Example 5

[0088] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which comprises the following steps:

[0089] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0090] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0091] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed for 30 min in a reaction kettle to obtain an oligomer;

[0092] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0093] (5) adding 0.4 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C., with mechanical stirring for 10 to 15 minutes;

[0094] (6) After the chain extension is completed, the oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0095] The tensile strength of the prepared fluorine-containing high-temperature resistant polyurea composite material is 50.93MPa, the elongation at break ranges from 1005%, the adhesion to the hydrophilic polymer substrate can reach 9.59MPa, and the temperature at which the mass loss rate is 5% is 526°C.

[0096] Example 6

[0097] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which comprises the following steps:

[0098] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0099] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0100] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed for 30 min in a reaction kettle to obtain an oligomer;

[0101] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0102] (5) adding 0.6 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C., with mechanical stirring for 10 to 15 minutes;

[0103] (6) After the chain extension is completed, the oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0104] The prepared fluorine-containing high-temperature resistant polyurea composite material has a tensile strength of 47.53 MPa, an elongation at break of 922%, an adhesion to a hydrophilic polymer substrate of up to 10.34 MPa, and a temperature of 517°C when the mass loss rate is 5%.

[0105] Example 7

[0106] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which comprises the following steps:

[0107] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0108] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0109] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed for 30 min in a reaction kettle to obtain an oligomer;

[0110] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0111] (5) adding 0.7 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C., with mechanical stirring for 10 to 15 minutes;

[0112] (6) After the chain extension is completed, the oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0113] The tensile strength of the prepared fluorine-containing high-temperature resistant polyurea composite material is 44.52MPa, the elongation at break ranges from 839%, the adhesion to the hydrophilic polymer substrate can reach 8.84MPa, and the temperature at which the mass loss rate is 5% is 500°C.

[0114] Example 8

[0115] A method for preparing a fluorine-containing high-strength and high-temperature resistant polyurea material, the process flow of which comprises the following steps:

[0116] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0117] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, the temperature was raised to 85° C. and helium was quickly introduced. The mixture was stirred at high speed for 3 h to obtain prepolymer A.

[0118] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed for 30 min in a reaction kettle to obtain an oligomer;

[0119] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0120] (5) adding 0.8 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, and carrying out a chain extension reaction at 25 to 35° C., with mechanical stirring for 10 to 15 minutes;

[0121] (6) After the chain extension is completed, the oligomer is stirred for 45 minutes and then introduced into a mold for curing to obtain the final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0122] The prepared fluorine-containing high-temperature resistant polyurea composite material has a tensile strength of 38.61 MPa, an elongation at break of 793%, an adhesion to a hydrophilic polymer substrate of up to 8.05 MPa, and a temperature of 494°C when the mass loss rate is 5%.

[0123] Example 9

[0124] A fluorine-containing high-strength and high-temperature resistant polyurea material is used as a protective coating, and its preparation method comprises the following steps:

[0125] (1) Dehydrate isophorone diisocyanate (IPDI) and polyetheramine D230 at 100° C. under vacuum for 1 h, then take them out and cool them to room temperature for later use;

[0126] (2) 12.17 g of IPDI was weighed and placed in a three-necked flask, and then 4.36 g of D230 was added dropwise. After stirring for 30 min, 10% of ethyl acetate (EAc) and 20% of calcium carbonate filler, which were the mass percentages of prepolymer A, were added and stirred evenly. After heating to 85° C., helium was quickly introduced and stirred at high speed for 3 h to obtain prepolymer A;

[0127] (3) 0.231 g of maleic anhydride and prepolymer A were stirred at high speed for 30 min in a reaction kettle to obtain an oligomer;

[0128] (4) After the obtained prepolymer A is cooled to room temperature, it is placed in an ice-water mixture container and mechanically stirred for 10 to 20 minutes;

[0129] (5) adding 0.5 g of tetrafluorobutanediol as a chain extender to the oligomer after low temperature stirring, adding 0.5% of KH550 and dispersant BYK110 accounting for 0.5% of the mass percentage of prepolymer A, and carrying out chain extension reaction at 25-35° C., the reaction is stirred mechanically for 10-15 minutes;

[0130] (6) After the chain-extended oligomer is stirred for 45 minutes, a pigment, a defoamer and an antioxidant are added, the mixture is evenly mixed, and the mixture is introduced into a mold for curing to obtain a final fluorine-containing high-strength and high-temperature resistant polyurea material.

[0131] Comparative Example 1

[0132] The same as Example 1, except that, when 0.05 g of tetrafluorobutanediol was added, the tensile strength, elongation at break and adhesion to the hydrophilic polymer substrate of the prepared fluorinated high-temperature resistant polyurea composite material did not decrease significantly, but the temperature at which the mass loss rate was 5% was only 337°C, indicating that its high-temperature resistance performance was significantly reduced.

[0133] Comparative Example 2

[0134] The same as Example 1, except that, by adding 5 g of tetrafluorobutanediol, the tensile strength, elongation at break and adhesion to the hydrophilic polymer substrate of the prepared fluorine-containing high-temperature resistant polyurea composite material are significantly reduced, which are 16.75 MPa, 451% and 2.55 MPa, respectively. The temperature at which the mass loss rate is 5% is only 216°C, which is a significant decrease. This is because the addition of excessive tetrafluorobutanediol causes excessive hydroxyl groups to enter the polyurea system. Due to the enhanced intermolecular entanglement caused by the interaction between hydroxyl molecules, the fluidity of the binder is greatly reduced, and even gelation occurs. During application, uneven distribution occurs, which destroys the stability of the polyurea system.

[0135] Comparative Example 3

[0136] Tetrafluoropropanol is used to replace tetrafluorobutanediol, and its structural formula is:

[0137]

[0138] When 0.5 g of tetrafluoropropanol was added and the other conditions were the same as those in Test Example 1, the mechanical properties of the prepared fluorinated polyurea composite material were significantly reduced and lower than those of the ordinary polyurea composite material. The temperature when the mass loss rate of the polyurea composite material was 5% was only 122°C, which shows that not all fluorinated compounds can improve the high temperature resistance of the polyurea material. This is because the fluorine group of tetrafluoropropanol cannot be evenly distributed in the polyurea material like the fluorine group of tetrafluorobutanediol, and has poor solubility with the polyurea group. In addition, the hydroxyl content in the system increases, the intermolecular force becomes larger, and the system is too viscous, resulting in poor reinforcement effect on the polyurea.

[0139] Comparative Example 4

[0140] When terminal hydroxyl-containing fluorinated silicone is used to replace tetrafluorobutanediol, the mass of terminal hydroxyl-containing fluorinated silicone added is 0.5 g, and the other conditions are the same as those in Test Example 1, the mechanical properties of the prepared fluorinated polyurea composite material are significantly reduced, and the high temperature resistance has no obvious change. This is because the compatibility between the terminal hydroxyl group of the terminal hydroxyl-containing fluorinated silicone and the polyurea group may be poor, resulting in weak interfacial adhesion between the polyurea matrix and the additive, which will cause the material to be fragile when subjected to force, thereby resulting in a decrease in mechanical properties.

[0141] Test Example 1

[0142] A high temperature stability test of a fluorine-containing high-strength and high-temperature resistant polyurea material comprises the following steps:

[0143] The fluorine-containing high-strength and high-temperature resistant polyurea material obtained in Example 1-1 was analyzed by a thermogravimetric analyzer, and the experimental data were recorded to analyze the high-temperature stability of the material.

[0144] Depend on Figure 2The temperature change trend shows that the temperature at the sample mass loss rate of 5% increases first and then decreases with the increase of tetrafluorobutanediol addition. When the amount of tetrafluorobutanediol added is 0.5g, the temperature at the sample mass loss rate of 5% is the highest at 568℃. This is because when the amount of tetrafluorobutanediol added is appropriate, CF Key The bond is very strong, forming a very stable bond with a high energy binding ratio, making these materials not easily destroyed by heat, chemicals and other factors, thus having high temperature resistance. In addition, due to the small size and simple molecular chain structure of fluorinated polyurea, they are less affected by thermal motion in high temperature environments, and the force between molecules is also relatively small, thus having certain high temperature resistance.

[0145] Test Example 2

[0146] A tensile property test of a fluorine-containing high-strength and high-temperature resistant polyurea material comprises the following steps:

[0147] The composite material made of fluorine-containing high-strength and high-temperature resistant polyurea material obtained by the method in Example 1-1 was subjected to a tensile test using a tensile testing machine, and the experimental data were recorded to analyze the tensile strength and elongation at break of the material. The test was carried out at a strain rate of 50 mm / min, and at least three samples were tested according to ISO 37-2005. The tensile test piece was 35 mm long, 2 mm wide in the middle, 1 mm thick, and had a gauge length of 10 mm.

[0148] Depend on Figure 3 It can be seen that the tensile strength and elongation at break of the fluorine-containing high-temperature resistant polyurea composite material both show a trend of first increasing and then decreasing with the increase in the amount of tetrafluorobutanediol added. When the amount of tetrafluorobutanediol added is 0.5g, the maximum tensile strength of the modified polyurea composite material is 53.85MPa; when the amount of tetrafluorobutanediol added is 0.3g, the maximum elongation at break of the modified polyurea composite material is 1029%. This is because the mechanical properties of polyurea materials are often determined by the hard segment chain, and the addition of fluorine elements significantly enhances the structure of the hard segment chain, thereby significantly improving the tensile strength. From the experimental results, it can be seen that the addition of tetrafluorobutanediol can ensure the tensile strength of the composite material made of polyurea coating while improving its willfulness.

[0149] Test Example 3

[0150] A test of the adhesion of a fluorine-containing high-strength and high-temperature resistant polyurea material to a hydrophilic polymer substrate comprises the following steps:

[0151] The adhesion test was performed using a pull-off adhesion tester from DeFelsko, USA ( AT). At least four samples were tested according to ASTM D4541. Before testing, ensure that the coating surface on the substrate is clean and free of contamination; stick a suitable size ingot on the coating surface with a suitable adhesive and ensure that the adhesive is fully cured; record the maximum tensile force when the coating is separated, and observe and record the separation mode (such as coating self-destruction, coating and substrate interface separation, substrate destruction, etc.).

[0152] Depend on Figure 4 It can be seen that the adhesion of fluorine-containing high-temperature resistant polyurea composite materials to hydrophilic polymer substrates shows a trend of increasing online and then decreasing with the addition of tetrafluorobutanediol. When the addition amount of tetrafluorobutanediol is 0.5g, the maximum adhesion is 10.7MPa. This is because the hydrogen bonds in the modified polyurea system will increase with the addition amount of tetrafluorobutanediol, and at the same time, the fluidity of the polyurea coating will increase to a certain extent, thereby increasing the wetting degree of the substrate. Therefore, the adhesion of the modified polyurea coating to the centralized procurement is significantly increased.

Claims

1. A fluorine-containing high-strength and high-temperature resistant polyurea material, characterized in that: The raw materials of the fluorine-containing high-strength and high-temperature resistant polyurea material are polyurea raw materials and tetrafluorobutanediol; in terms of mass ratio, the polyurea raw materials:tetrafluorobutanediol=2:(1-1.4); when the mass loss rate of the fluorine-containing high-strength and high-temperature resistant polyurea material is 5%, the temperature is 480-570°C, the bonding strength is 11-16MPa, and the shear strength is 22-30MPa.

2. The fluorine-containing high-strength and high-temperature resistant polyurea material according to claim 1, characterized in that: The tensile strength of the fluorine-containing high-strength and high-temperature resistant polyurea material is in the range of 32MPa to 54MPa, the elongation at break is in the range of 714% to 1030%, and the adhesion to the hydrophilic polymer substrate can reach 8 to 11MPa.

3. The fluorine-containing high-strength and high-temperature resistant polyurea material according to claim 1, characterized in that: The raw materials of the polyurea include isocyanate, macromolecular diamine and maleic anhydride; in molar ratio, isocyanate, macromolecular diamine: maleic anhydride = 1: (2-3): (2-3).

4. The method for synthesizing the fluorine-containing high-strength and high-temperature resistant polyurea material according to claim 1, characterized in that: The following steps are involved: S1: weighing the raw materials of polyurea according to the ratio, vacuum dehydrating them respectively, cooling them to room temperature, and obtaining dehydrated isocyanate, dehydrated macromolecular diamine, and dehydrated maleic anhydride respectively; S2: Under an inert gas, the dehydrated isocyanate and the dehydrated macromolecular diamine are mixed, stirred evenly, and heated to 85-90° C. for prepolymerization for 2-3 hours to obtain prepolymer A; S3: stirring the dehydrated maleic anhydride and prepolymer A for 20 to 30 minutes to obtain an oligomer; wherein the stirring rate is 500 to 700 rpm; S4: cooling the oligomer to room temperature, stirring at 0°C for 10 to 20 minutes at a stirring rate of 500 to 700 rpm to obtain a low-temperature stirred oligomer; S5: subjecting tetrafluorobutanediol and the oligomer after low-temperature stirring to a chain extension reaction at 25-35° C. to obtain an oligomer after chain extension; wherein the stirring rate of the chain extension reaction is 500-700 rpm until the stirring is uniform; S6: After the chain extension is completed, the oligomer is uniformly stirred for 30 to 60 minutes, and then cured to obtain a fluorine-containing high-strength and high-temperature resistant polyurea material.

5. The method for synthesizing the fluorine-containing high-strength and high-temperature resistant polyurea material according to claim 4, characterized in that: In the S1, the temperature of vacuum dehydration is 100-105°C, and the dehydration time is more than 1 hour; and / or, in the S2, the inert gas is one of argon, helium, and nitrogen; and / or, in the S3, the molar ratio of maleic anhydride: prepolymer A = (2-3): 1; and / or, in the S5, the molar ratio of tetrafluorobutanediol: low-temperature stirred oligomer = 1:2; and / or, in the S6, the curing temperature is 65-85°C, and the curing time is 24h to 72h.

6. Use of the fluorine-containing high-strength and high-temperature resistant polyurea material according to any one of claims 1 to 3 as a protective coating.

7. The use of the fluorine-containing high-strength and high-temperature resistant polyurea material according to claim 6, characterized in that: The fluorine-containing high-strength and high-temperature resistant polyurea material is added with one or more of diluents, fillers, coupling agents, dispersants, pigments, defoamers or antioxidants according to the specific use and functional characteristics of the protective coating.

8. The use of the fluorine-containing high-strength and high-temperature resistant polyurea material according to claim 7, characterized in that: The diluent includes but is not limited to one or more of ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, and ethyl 3-ethoxypropionate; the amount of the diluent used may account for 5 to 30% of the total weight of the prepolymer component A; The filler is selected from one or more of calcium carbonate, talcum powder, titanium dioxide, silicon powder, and barium sulfate; the total amount of the filler used can account for 10-50% of the total weight of the prepolymer component A; The coupling agent is a silane coupling agent, and the amount of the coupling agent used is 0.1% to 1% of the total weight of the filler in the prepolymer component A; The dispersant is selected from one or more of BYK110, BYK163, and BYK180; The pigment is selected from one or more of carbon black, titanium dioxide, iron yellow, iron red, and phthalocyanine blue; The defoaming agent is selected from one or more of BYK066N and BYK085; The antioxidant is selected from one or more of BASF1010, BASF B225 and BASF1330.

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