Polyborosiloxane modified polyaspartic acid ester and preparation method thereof, polyurea coating

Abstract

The present application provides a polyborosiloxane-modified polyaspartic acid ester and a preparation method thereof, and a polyurea coating, and relates to the technical field of coatings. The structure of the polyborosiloxane-modified polyaspartic acid ester provided in the present application includes an amino-terminated polyborosiloxane, and the Si-O bond and the B-O bond of the amino-terminated polyborosiloxane have high bond energy, a long bond length and a large bond angle. The polyurea coating synthesized from the polyborosiloxane-modified polyaspartic acid ester has good heat resistance, weather resistance, hydrophobicity and elongation at break.

Description

Technical Field

[0001] The present application relates to the technical field of coatings, and in particular to a polyborosiloxane-modified polyaspartic acid ester and a preparation method thereof, and a polyurea coating. Background Art

[0002] Aliphatic polyaspartic polyurea coating is a new type of polyurea coating developed in recent years. It is called the "third generation polyurea" and has the characteristics of high solid and low viscosity, good mechanical properties, aging resistance, corrosion resistance, etc. However, compared with aromatic polyurea, the lack of benzene ring in aliphatic polyaspartic polyurea reduces the heat resistance of the material. In order to improve the heat resistance of polyurea and expand its application range, polyurea is generally modified. In recent years, silicone-modified polyurea coatings have become a research hotspot. Since silicone has excellent heat resistance, hydrophobicity, low temperature resistance and other characteristics, it greatly improves the heat resistance of polyurea coatings.

[0003] Chinese patent CN109467571A discloses the use of maleic acid ester and polyethylene polyamine to react, and the generated intermediate is then reacted with a glycidyl propyl methyl diethoxy silane coupling agent to obtain siloxane-modified aspartic acid ester, but the siloxane bond is not the main chain, but the side chain, and as a side chain, it cannot better improve the hydrophobicity, heat resistance, tensile strength and elongation of the material. Patent CN113603717A discloses the use of polyamine-terminated siloxane-based primary amine to modify asparagine polyurea resin, but its siloxane bond is located at the end of the chain, which plays a capping role, and the content of siloxane bonds in the main chain cannot be controlled, and the hydrophobicity, heat resistance, tensile strength and elongation of the material cannot be better improved. Summary of the invention

[0004] The purpose of the present application is to provide a polyborosiloxane modified polyaspartic acid ester and a preparation method thereof, and a polyurea coating, aiming to solve the problem that the existing silicone modified polyurea coating cannot better improve the hydrophobicity, heat resistance, tensile strength and elongation of the material.

[0005] To achieve the above objectives, the present application provides a polyborosiloxane-modified polyaspartic acid ester, the chemical structure of which is shown in Formula I:

[0006] Formula I;

[0007] Wherein, R and R1 are each independently selected from a C1-C5 saturated alkyl group; R2, R3, and R4 are each independently selected from a C1-C5 alkyl group, a hydrogen atom, an aryl group, an alkoxy group, an ester group, and a heterocyclic substituent; n and m are each independently an integer of 1 to 20;

[0008] The polyborosiloxane modified polyaspartic acid ester is obtained by an addition reaction of amino-terminated polyborosiloxane and maleic acid diester; the number average molecular weight of the amino-terminated polyborosiloxane is 800-2000.

[0009] In some embodiments, R and R1 are each independently selected from one or more of -CH3, -CH2CH3, -CH2CH2CH3, -CH (CH3) CH3, -CH2CH2CH2CH3, -CH(CH3)CH2CH3, -CH2CH(CH3)CH3, -CH2CH2CH(CH3)2, and -C(CH3)3.

[0010] The present application also provides a method for preparing the above-mentioned polyborosiloxane-modified polyaspartic acid ester, comprising:

[0011] Adding the first siloxane, boric acid and water into the alcohol solution to obtain polyborosiloxane through hydrolysis condensation reaction;

[0012] The polyborosiloxane is terminated with a second siloxane, wherein the second siloxane is an amino-terminated siloxane, to obtain an amino-terminated polyborosiloxane;

[0013] The amino-terminated polyborosiloxane and maleic acid diester are subjected to an addition reaction to obtain polyborosiloxane-modified polyaspartic acid ester.

[0014] In some embodiments, at least one of the following conditions is met:

[0015] A. the molar ratio of the first siloxane to the boric acid is 1:1 to 3:1;

[0016] B. the mass of the water is 0.1% to 1% of the sum of the mass of the first siloxane and the boric acid;

[0017] C. the alcohol solution is selected from any one or more combinations of ethanol solution, propanol solution, and isopropanol solution;

[0018] D. The catalyst for the hydrolysis condensation reaction is any one or more combinations of hydrochloric acid, acetic acid, dilute sulfuric acid, and ammonia water;

[0019] E. The reaction temperature of the hydrolysis condensation reaction is 60-80°C, and the reaction time is 2-3 hours.

[0020] In some embodiments, at least one of the following conditions is met:

[0021] A. the molar ratio of the second siloxane to the first siloxane is 1:1 to 3:1;

[0022] B. the second siloxane is selected from: at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, aminoethylaminopropyltriethoxysilane, aminoethylaminopropylmethyldiethoxysilane, aminoethylaminopropylmethyldimethoxysilane, aminoethylaminomethyltriethoxysilane and aminoethylaminomethylmethyldiethoxysilane;

[0023] C. The end-capping time is 2 to 3 hours;

[0024] D. The number average molecular weight of the amino-terminated polyborosiloxane is 800-2000.

[0025] In some embodiments, at least one of the following conditions is met:

[0026] A. the molar ratio of the amino-terminated polyborosiloxane to the maleic acid diester is 1:2 to 1:2.2;

[0027] B. The addition reaction comprises: adding the amino-terminated polyborosiloxane and the catalyst into a reaction vessel, heating for the first time and adding dimethyl maleate dropwise after nitrogen is passed, and after the addition is complete, heating for the second time and reacting at a constant temperature;

[0028] C. On the basis of satisfying condition B, the first heating is increased to 50-60°C;

[0029] D. On the basis of satisfying condition B, the second heating is performed to 80-120°C.

[0030] In some embodiments, the catalyst is selected from any one or more combinations of sodium methoxide, triethylamine, tetramethylguanidine, tetrabutylammonium hydroxide, and 1,8-diazabicyclo[5.4.0]undec-7-ene;

[0031] And / or, the mass of the catalyst is 0.01-0.1% of the mass of the amino-terminated polyborosiloxane.

[0032] The present application also provides a polyurea coating, comprising a first component and a second component, wherein the first component comprises the above-mentioned polyborosiloxane-modified polyaspartic acid ester, and the second component is an isocyanate-containing structural component;

[0033] Wherein, the molar ratio of the isocyanate groups in the isocyanate structural component to the polyborosiloxane-modified polyaspartic acid ester is 1:1 to 1.1:1.

[0034] In some embodiments, the first component includes, by mass, 65 to 80 parts of polyborosiloxane modified polyaspartic acid ester, 15 to 30 parts of titanium dioxide, 0.2 to 1.0 parts of dispersant, 0.2 to 1.0 parts of defoaming agent, 0.2 to 1.0 parts of leveling agent, and 1.0 to 2.0 parts of anti-settling agent.

[0035] In some embodiments, the isocyanate structural component includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate.

[0036] Compared with the prior art, the beneficial effects of this application include:

[0037] The structure of the polyborosiloxane modified polyaspartic acid ester provided by the present application includes amino-terminated polyborosiloxane, the Si-O bond and BO bond of the amino-terminated polyborosiloxane have high bond energy, long bond length and large bond angle, and the polyurea coating synthesized from the polyborosiloxane modified polyaspartic acid ester has good heat resistance, weather resistance, hydrophobicity and elongation at break. The present application introduces the boron element to form a BO covalent bond, and the boron atom with an electron vacancy can act as an acceptor of the unshared electron pair of oxygen in the adjacent molecular chain, thereby forming an electron bridge between the adjacent molecular chains, causing weak bonding between molecules, which can further improve the weather resistance and hydrophobicity of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0039] Figure 1 The schematic diagram is a process flow diagram of the preparation method of the polyborosiloxane modified polyaspartic acid ester of the present application. DETAILED DESCRIPTION

[0040] As used herein:

[0041] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0042] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0043] When an amount, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when a range of "1 to 5" is disclosed, the described range should be interpreted as including ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this article, unless otherwise stated, the range is intended to include its end values ​​and all integers and fractions within the range.

[0044] In these examples, parts and percentages are by mass unless otherwise indicated.

[0045] "Mass parts" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass parts of component A are a parts and the mass parts of component B are b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0046] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0047] The present application provides a polyborosiloxane modified polyaspartic acid ester, the chemical structure of which is shown in Formula I:

[0048] Formula I;

[0049] Wherein, R and R1 are each independently selected from a C1-C5 saturated alkyl group; R2, R3, and R4 are each independently selected from a C1-C5 alkyl group, a hydrogen atom, an aryl group, an alkoxy group, an ester group, and a heterocyclic substituent; n and m are each independently an integer of 1 to 20;

[0050] The polyborosiloxane modified polyaspartic acid ester is obtained by an addition reaction of amino-terminated polyborosiloxane and maleic acid diester; the number average molecular weight of the amino-terminated polyborosiloxane is 800-2000.

[0051] Wherein, when R2, R3, and R4 are independently selected from C1-C5 alkyl, they may be saturated alkyl or unsaturated alkyl. n and m may be, for example, independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.

[0052] In some embodiments, R and R1 are each independently selected from one or more of -CH3, -CH2CH3, -CH2CH2CH3, -CH (CH3) CH3, -CH2CH2CH2CH3, -CH(CH3)CH2CH3, -CH2CH(CH3)CH3, -CH2CH2CH(CH3)2, and -C(CH3)3.

[0053] In some embodiments, the number average molecular weight of the amino-terminated polyborosiloxane can be, for example, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000 or any value between 800 and 2000.

[0054] The present application also provides a method for preparing the above-mentioned polyborosiloxane-modified polyaspartic acid ester, please refer to Figure 1 ,include:

[0055] S100: adding a first siloxane, boric acid and water into an alcohol solution to obtain polyborosiloxane through a hydrolysis condensation reaction.

[0056] In some embodiments, the molar ratio of the first siloxane to the boric acid is 1:1 to 3:1, for example, 1:1, 1.5:1, 2:1, 2.5:1, 3:1 or any value between 1:1 and 3:1. The first siloxane needs to be capable of undergoing a hydrolysis condensation reaction, for example, ethyl orthosilicate, methyl orthosilicate or dichlorosilane.

[0057] In some embodiments, the mass of the water is 0.1% to 1% of the sum of the masses of the first siloxane and the boric acid, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1% or any value between 0.1% and 1%.

[0058] In some embodiments, the alcohol solution is selected from any one or more combinations of ethanol solution, propanol solution, and isopropanol solution.

[0059] In some embodiments, the catalyst for the hydrolysis condensation reaction is any one or more of hydrochloric acid, acetic acid, dilute sulfuric acid, and ammonia water.

[0060] In some embodiments, the amount of the catalyst added is 0.05% to 0.15% of the sum of the mass of the first siloxane and the boric acid, for example, it can be 0.05%, 0.07%, 0.1%, 0.12%, 0.15% or any value between 0.05% and 0.15%.

[0061] In some embodiments, the reaction temperature of the hydrolysis condensation reaction is 60-80°C, for example, 60°C, 65°C, 70°C, 75°C, 80°C or any value between 60-80°C, and the reaction time is 2-3 hours.

[0062] The structural formula of the polyborosiloxane obtained after step S100 is shown in Formula II.

[0063] Formula II;

[0064] Wherein, R2, R3, and R4 are each independently selected from one of C1-C5 alkyl, hydrogen atom, aryl, alkoxy, ester group, and heterocyclic substituent; n and m are each independently an integer of 1 to 20.

[0065] S200: The polyborosiloxane is terminated with a second siloxane, wherein the second siloxane is an amino-terminated siloxane, to obtain an amino-terminated polyborosiloxane.

[0066] In some embodiments, the molar ratio of the second siloxane to the first siloxane is 1:1-3:1, for example, 1:1, 1.5:1, 2:1, 2.5:1, 3:1 or any value between 1:1-3:1.

[0067] In some embodiments, the second siloxane is selected from at least one of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, aminoethylaminopropyltriethoxysilane, aminoethylaminopropylmethyldiethoxysilane, aminoethylaminopropylmethyldimethoxysilane, aminoethylaminomethyltriethoxysilane, and aminoethylaminomethylmethyldiethoxysilane.

[0068] In some embodiments, the blocking time is 2 to 3 hours.

[0069] In some embodiments, the amino-terminated polyborosiloxane has a number average molecular weight of 800-2000, for example, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000 or any value between 800 and 2000.

[0070] The structural formula of the amino-terminated polyborosiloxane obtained after step S200 is shown in Formula III:

[0071] Formula III.

[0072] S300: Addition reaction of amino-terminated polyborosiloxane and maleic acid diester to obtain polyborosiloxane-modified polyaspartic acid ester.

[0073] In some embodiments, the molar ratio of the amino-terminated polyborosiloxane to the maleic acid diester is 1:2 to 1:2.2 to ensure that the amino-terminated polyborosiloxane reacts completely with the maleic acid diester to convert the primary amine into a secondary amine. The structural formula of the maleic acid diester is shown in Formula IV.

[0074] Formula IV, wherein R and R1 are each independently selected from C1-C5 saturated alkyl.

[0075] In some embodiments, the addition reaction comprises: adding the amino-terminated polyborosiloxane and the catalyst into a reaction container, heating for the first time and adding dimethyl maleate dropwise after nitrogen is introduced, and after the addition is complete, heating for the second time and reacting at a constant temperature.

[0076] Wherein, the first heating to 50-60°C may be, for example, 50°C, 52°C, 55°C, 57°C, 60°C or any value between 50-60°C; the second heating to 80-120°C may be, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C.

[0077] In some embodiments, the catalyst is selected from any one or more combinations of sodium methoxide, triethylamine, tetramethylguanidine (TMG), tetrabutylammonium hydroxide, and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0078] In some embodiments, the mass of the catalyst is 0.01-0.1% of the mass of the amino-terminated polyborosiloxane.

[0079] The present application also provides a polyurea coating, comprising a first component and a second component, wherein the first component comprises the above-mentioned polyborosiloxane-modified polyaspartic acid ester, and the second component is an isocyanate structure-containing component; wherein the molar ratio of the isocyanate group in the isocyanate structure-containing component to the polyborosiloxane-modified polyaspartic acid ester is 1:1~1.1:1.

[0080] In some embodiments, the first component includes, by mass, 65 to 80 parts of polyborosiloxane modified polyaspartic acid ester, 15 to 30 parts of titanium dioxide, 0.2 to 1.0 parts of dispersant, 0.2 to 1.0 parts of defoaming agent, 0.2 to 1.0 parts of leveling agent, and 1.0 to 2.0 parts of anti-settling agent.

[0081] The dispersant may be, for example, BYK110, the defoamer may be, for example, BYK1790, the leveling agent may be, for example, EAB380-20, and the anti-settling agent may be, for example, BYK-410.

[0082] In some embodiments, the isocyanate-containing structural component includes at least one of toluene diisocyanate (TDI), isophorone diisocyanate (IPDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), and hexamethylene diisocyanate (HDI).

[0083] The structure of the polyborosiloxane modified polyaspartic acid ester provided in the present application includes amino-terminated polyborosiloxane, the Si-O bond and the BO bond of the amino-terminated polyborosiloxane have high bond energy, a longer bond length and a larger bond angle, and the polyurea coating synthesized from the polyborosiloxane modified polyaspartic acid ester has good heat resistance, weather resistance, hydrophobicity and elongation at break.

[0084] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0085] Example 1

[0086] Embodiment 1 First, a polyborosiloxane-modified polyaspartic acid ester is provided, and the preparation method thereof comprises:

[0087] Weigh 2 mol of ethyl orthosilicate, 1 mol of boric acid and 2 g of water, add to 50 mL of ethanol solution, heat to 70°C, add 0.5 g of dilute hydrochloric acid, react for 2 hours, then add 2 mol of 3-aminopropyltriethoxysilane, react for 2 hours, keep warm, distill under reduced pressure (-0.1 MPa) to remove water and ethanol, and obtain colorless and transparent amino-terminated polyborosiloxane after vacuum drying. The number average molecular weight measured by GPC is 1020.

[0088] Weigh 1 mol of amino-terminated polyborosiloxane and 0.5 g of catalyst TMG, put them in a three-necked flask, pass nitrogen for 30 minutes, stir and heat to 60°C, start to add 2 mol of dimethyl maleate, and control the dropping rate at 2 drops / second. After the addition is completed, start to heat to 100°C. When the primary amine in the system is completely converted into secondary amine, the reaction is completed to obtain the polyborosiloxane modified aspartic acid ester of Example 1.

[0089] Example 1 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of polyborosiloxane modified aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Example 1.

[0090] Example 2

[0091] Embodiment 2 First, a polyborosiloxane-modified polyaspartic acid ester is provided, and the preparation method thereof comprises:

[0092] Weigh 1.5 mol of ethyl orthosilicate, 1 mol of boric acid and 2 g of water, add to 50 mL of ethanol solution, heat to 60°C, add 0.5 g of dilute hydrochloric acid, react for 2 hours, then add 1.5 mol of 3-aminopropyltriethoxysilane, react for 2 hours, keep warm, distill under reduced pressure (-0.1 MPa) to remove water and ethanol, and vacuum dry to obtain colorless and transparent amino-terminated polyborosiloxane, the number average molecular weight of which is 830 as measured by GPC.

[0093] Weigh 1 mol of amino-terminated polyborosiloxane and 0.5 g of catalyst TMG, place them in a three-necked flask, pass nitrogen for 30 min, stir and heat to 60°C, start to drop 2 mol of dimethyl maleate, and control the drop rate at 2 drops / second. After the drop addition is completed, start to heat to 100°C. When the primary amine in the system is completely converted into secondary amine, the reaction is completed to obtain the polyborosiloxane-modified aspartic acid ester of Example 2.

[0094] Example 2 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of polyborosiloxane modified aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Example 2.

[0095] Example 3

[0096] Embodiment 3 Firstly, a polyborosiloxane-modified polyaspartic acid ester is provided, and the preparation method thereof comprises:

[0097] Weigh 2 mol of ethyl orthosilicate, 1 mol of boric acid and 2 g of water, add to 50 mL of ethanol solution, heat to 75°C, add 0.5 g of dilute hydrochloric acid, react for 2.5 hours, then add 2 mol of 3-aminopropyltriethoxysilane, react for 2.5 hours, keep warm, distill under reduced pressure (-0.1 MPa) to remove water and ethanol, and vacuum dry to obtain colorless and transparent amino-terminated polyborosiloxane, the number average molecular weight of which is 1520 as measured by GPC.

[0098] Weigh 1 mol of amino-terminated polyborosiloxane and 0.5 g of catalyst TMG, put them in a three-necked flask, pass nitrogen for 30 minutes, stir and heat to 60°C, start to add 2 mol of dimethyl maleate, and control the dropping rate at 2 drops / second. After the addition is completed, start to heat to 100°C. When the primary amine in the system is completely converted into secondary amine, the reaction is completed to obtain the polyborosiloxane modified aspartic acid ester of Example 3.

[0099] Example 3 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of polyborosiloxane modified aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Example 3.

[0100] Example 4

[0101] Embodiment 4 First, a polyborosiloxane-modified polyaspartic acid ester is provided, and its preparation method comprises:

[0102] Weigh 2.5 mol of ethyl orthosilicate, 1 mol of boric acid and 2 g of water, add to 50 mL of ethanol solution, heat to 75°C, add 0.5 g of dilute hydrochloric acid, react for 2.5 hours, then add 2.5 mol of 3-aminopropyltriethoxysilane, react for 2.5 hours, keep warm, distill under reduced pressure (-0.1 MPa) to remove water and ethanol, and vacuum dry to obtain colorless and transparent amino-terminated polyborosiloxane, the number average molecular weight of which is 1960 as measured by GPC.

[0103] Weigh 1 mol of amino-terminated polyborosiloxane and 0.5 g of catalyst TMG, put them in a three-necked flask, pass nitrogen for 30 minutes, stir and heat to 60°C, start to add 2 mol of dimethyl maleate, and control the dropping rate at 2 drops / second. After the addition is completed, start to heat to 100°C. The reaction is completed when the primary amine in the system is completely converted into secondary amine to obtain the polyborosiloxane modified aspartic acid ester of Example 4.

[0104] Example 4 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of polyborosiloxane modified aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Example 4.

[0105] Example 5

[0106] Embodiment 5 Firstly, a polyborosiloxane modified polyaspartic acid ester is provided, and the preparation method thereof comprises:

[0107] Weigh 1 mol of ethyl orthosilicate, 1 mol of boric acid and 2 g of water, add to 50 mL of ethanol solution, heat to 70°C, add 0.5 g of dilute hydrochloric acid, react for 2 hours, then add 1 mol of 3-aminopropyltriethoxysilane, react for 1 hour, keep warm, distill under reduced pressure (-0.1 MPa) to remove water and ethanol, and vacuum dry to obtain colorless and transparent amino-terminated polyborosiloxane, the number average molecular weight of which is 660 as measured by GPC.

[0108] Weigh 1 mol of amino-terminated polyborosiloxane and 0.5 g of catalyst TMG, put them in a three-necked flask, pass nitrogen for 30 minutes, stir and heat to 60°C, start to add 2 mol of dimethyl maleate, and control the dropping rate at 2 drops / second. After the addition is completed, start to heat to 100°C. When the primary amine in the system is completely converted into secondary amine, the reaction is completed to obtain the polyborosiloxane-modified aspartic acid ester of Example 5.

[0109] Example 5 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of polyborosiloxane modified aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Example 5.

[0110] Example 6

[0111] Example 6 First, a polyborosiloxane-modified polyaspartic acid ester is provided, and the preparation method thereof comprises:

[0112] Weigh 3 mol of ethyl orthosilicate, 1 mol of boric acid and 2 g of water, add to 50 mL of ethanol solution, heat to 80°C, add 0.5 g of dilute hydrochloric acid, react for 3 hours, then add 3 mol of 3-aminopropyltriethoxysilane, react for 3 hours, keep warm, distill under reduced pressure (-0.1 MPa) to remove water and ethanol, and vacuum dry to obtain colorless and transparent amino-terminated polyborosiloxane, the number average molecular weight of which is 2530 as measured by GPC.

[0113] Weigh 1 mol of amino-terminated polyborosiloxane and 0.5 g of catalyst TMG, put them in a three-necked flask, pass nitrogen for 30 minutes, stir and heat to 60°C, start to add 2 mol of dimethyl maleate, and control the dropping rate at 2 drops / second. After the addition is completed, start to heat to 100°C. When the primary amine in the system is completely converted into secondary amine, the reaction is completed to obtain the polyborosiloxane modified aspartic acid ester of Example 6.

[0114] Example 6 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of polyborosiloxane modified aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Example 6.

[0115] The preparation parameters and number average molecular weights of amino-terminated polyborosiloxanes of Examples 1 to 6 are shown in Table 1.

[0116] Table 1 Preparation parameters and number average molecular weight of amino-terminated polyborosiloxanes of Examples 1 to 6

[0117]

[0118] Comparative Example 1

[0119] Comparative Example 1 First, an aspartic acid ester is provided, and its preparation method comprises:

[0120] Weigh 2 mol of hexamethylenediamine and 0.5 g of catalyst TMG, place them in a three-necked flask, pass nitrogen for 30 min, stir and heat to 60 ° C, start to drop 2 mol of dimethyl maleate, and control the drop rate at 2 drops / second. After the drop addition is completed, start to heat to 100 ° C. The reaction is completed when the primary amine in the system is completely converted into secondary amine to obtain the aspartic acid ester of Comparative Example 1.

[0121] Comparative Example 1 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane-modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Comparative Example 1.

[0122] Comparative Example 2

[0123] The commercially available aspartic acid ester polyurea coating STWD8027 was purchased from Shunde New Materials (Shanghai) Co., Ltd.

[0124] Comparative Example 3

[0125] Comparative Example 3 First, a polyborosiloxane-modified aspartic acid ester is provided, and the preparation method thereof comprises:

[0126] Weigh 2 mol of ethyl orthosilicate, 1 mol of boric acid, and 2 g of water, add them to 50 mL of ethanol solution, heat to 70° C., add 0.5 g of dilute hydrochloric acid, and react for 2 hours to obtain terminal hydroxyl polyborosiloxane with a molecular weight of 980.

[0127] Weigh 2 mol of hydroxy-terminated polysilicon boroxane and dissolve it in a xylene solution, then add 1 mol of dimethyl maleate, add 0.5 g of catalyst p-toluenesulfonic acid to carry out ester exchange reaction, heat and reflux for 5 hours, and then remove the xylene solvent in vacuo to obtain maleic acid polysilicon boroxane. Finally, maleic acid polysilicon boroxane ester and 2 mol of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane are reacted by passing nitrogen at 70 degrees Celsius for 20 hours through Michael addition reaction to obtain polyborosiloxane-modified aspartic acid ester.

[0128] Comparative Example 3 also provides a polyurea coating, including a first component and a second component, the first component includes, by mass, 70 parts of polyborosiloxane modified aspartic acid ester, 25 parts of titanium dioxide, 1 part of dispersant (BYK110), 1 part of defoamer (BYK1790), 1 part of leveling agent (EAB380-20), and 2 parts of anti-settling agent (BYK-410), and the second component is hexamethylene diisocyanate. The first component and the second component are mixed at a molar ratio of isocyanate group to polyborosiloxane modified polyaspartic acid ester of 1.05:1 and reacted at 100°C for 3 hours to obtain the polyurea coating of Comparative Example 3.

[0129] The polyurea coatings obtained in the above-mentioned Examples 1 to 6 and Comparative Examples 1 to 3 were respectively subjected to performance tests, and the test methods are as follows:

[0130] Water contact angle: The test is carried out in accordance with GB / T 30693-2014 Measurement of contact angle between plastic film and water.

[0131] Elongation at break: Elongation at break is tested according to GB / T 528-2009.

[0132] Heat resistance: Tested according to ISO 11358-1:2022 Thermogravimetric analysis of plastic polymers.

[0133] Aging resistance: Place the sample in a UV aging box at 65°C, relative humidity 65%, and irradiance 0.55W / m 2 , 340nm, UV aging for 720h. Measure the tensile strength retention rate of the product, tensile strength retention rate = tensile strength after aging / tensile strength before aging × 100%.

[0134] The test results are shown in Table 2. According to Table 2, the polyurea coatings prepared from the polyborosiloxane-modified polyaspartic acid esters of Examples 1 to 6 of the present application are significantly better than the polyurea coatings of Comparative Examples 1 and 2 in terms of water contact angle, elongation at break, heat resistance and aging resistance, indicating that the Si-O bond and the BO bond of the amino-terminated polyborosiloxane have high bond energy, a longer bond length and a larger bond angle, and the synthesized polyurea coating has good heat resistance, weather resistance and hydrophobicity.

[0135] The molecular weight of the amino-terminated polyborosiloxane for preparing polyborosiloxane-modified polyaspartic acid ester in Examples 1 to 4 is in the range of 800 to 2000. Compared with Example 5 (lower than 800) and Example 6 (higher than 2000), the performance of the polyurea coatings in Examples 1 to 4 is better.

[0136] Moreover, Examples 1 to 4 of the present application prepare polyborosiloxane-modified polyaspartic acid ester from polyborosiloxane with terminal amino groups. Compared with Comparative Example 3 in which polyborosiloxane-modified polyaspartic acid ester is prepared from polyborosiloxane with terminal hydroxy groups, the performance of the polyurea coatings of corresponding Examples 1 to 4 is significantly better than that of the polyurea coating of Comparative Example 3.

[0137] Table 2 Performance data of polyurea coatings of various embodiments and comparative examples

[0138]

[0139] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0140] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the above claims, any one of the claimed embodiments may be used in any combination. The information disclosed in this background technology section is intended only to deepen the understanding of the overall background technology of the present application and should not be regarded as an admission or in any form of implication that the information constitutes prior art known to those skilled in the art.

Claims

1. A polyborosiloxane-modified polyaspartic acid ester, characterized in that: Its chemical structure is shown in Formula I: Formula I; Wherein, R and R1 are each independently selected from a C1-C5 saturated alkyl group; R2 and R3 are each independently selected from an alkoxy group; R4 is a hydrogen atom; n and m are each independently an integer of 1 to 20; The polyborosiloxane modified polyaspartic acid ester is obtained by an addition reaction of amino-terminated polyborosiloxane and maleic acid diester; the number average molecular weight of the amino-terminated polyborosiloxane is 800-2000; The preparation method of the amino-terminated polyborosiloxane is: Adding the first siloxane, boric acid and water into the alcohol solution to obtain polyborosiloxane through hydrolysis condensation reaction; The polyborosiloxane is terminated with a second siloxane, wherein the second siloxane is an amino-terminated siloxane, to obtain an amino-terminated polyborosiloxane; The molar ratio of the first siloxane to the boric acid is 1:1-3:1; the first siloxane is tetraethyl orthosilicate.

2. The polyborosiloxane-modified polyaspartic acid ester according to claim 1, characterized in that: R and R1 are each independently selected from one or more of -CH3, -CH2CH3, -CH2CH2CH3, -CH (CH3) CH3, -CH2CH2CH2CH3, -CH(CH3)CH2CH3, -CH2CH(CH3)CH3, -CH2CH(CH3)CH3, -CH2CH2CH(CH3)2, and -C(CH3)3.

3. A method for preparing polyborosiloxane-modified polyaspartic acid ester according to claim 1 or 2, characterized in that: include: Adding the first siloxane, boric acid and water into the alcohol solution to obtain polyborosiloxane through hydrolysis condensation reaction; The polyborosiloxane is terminated with a second siloxane, wherein the second siloxane is an amino-terminated siloxane, to obtain an amino-terminated polyborosiloxane; The amino-terminated polyborosiloxane and maleic acid diester are subjected to an addition reaction to obtain polyborosiloxane-modified polyaspartic acid ester.

4. The method for preparing polyborosiloxane-modified polyaspartic acid ester according to claim 3, characterized in that: At least one of the following conditions is met: A. the molar ratio of the first siloxane to the boric acid is 1:1 to 3:1; B. the mass of the water is 0.1% to 1% of the sum of the mass of the first siloxane and the boric acid; C. the alcohol solution is selected from any one or more combinations of ethanol solution, propanol solution, and isopropanol solution; D. The catalyst for the hydrolysis condensation reaction is any one or more combinations of hydrochloric acid, acetic acid, dilute sulfuric acid, and ammonia water; E. The reaction temperature of the hydrolysis condensation reaction is 60-80°C, and the reaction time is 2-3 hours.

5. The method for preparing polyborosiloxane-modified polyaspartic acid ester according to claim 3, characterized in that: At least one of the following conditions is met: A. the molar ratio of the second siloxane to the first siloxane is 1:1 to 3:1; B. the second siloxane is 3-aminopropyltriethoxysilane; C. The end-capping time is 2 to 3 hours; D. The number average molecular weight of the amino-terminated polyborosiloxane is 800-2000.

6. The method for preparing polyborosiloxane-modified polyaspartic acid ester according to claim 3, characterized in that: At least one of the following conditions is met: A. the molar ratio of the amino-terminated polyborosiloxane to the maleic acid diester is 1:2 to 1:2.2; B. The addition reaction comprises: adding the amino-terminated polyborosiloxane and the catalyst into a reaction vessel, heating for the first time and adding dimethyl maleate dropwise after nitrogen is passed, and after the addition is complete, heating for the second time and reacting at a constant temperature; C. On the basis of satisfying condition B, the first heating is increased to 50-60°C; D. On the basis of satisfying condition B, the second heating is performed to 80-120°C.

7. The method for preparing polyborosiloxane-modified polyaspartic acid ester according to claim 6, characterized in that: The catalyst is selected from any one or more combinations of sodium methoxide, triethylamine, tetramethylguanidine, tetrabutylammonium hydroxide, and 1,8-diazabicyclo[5.4.0]undec-7-ene; And / or, the mass of the catalyst is 0.01-0.1% of the mass of the amino-terminated polyborosiloxane.

8. A polyurea coating, characterized in that: It comprises a first component and a second component, wherein the first component comprises the polyborosiloxane-modified polyaspartic acid ester according to claim 1 or 2, and the second component is an isocyanate structure-containing component; Wherein, the molar ratio of the isocyanate groups in the isocyanate-containing structural component to the polyborosiloxane-modified polyaspartic acid ester is 1:1 to 1.1:

1.

9. The polyurea coating according to claim 8, characterized in that: The first component comprises, by weight, 65 to 80 parts of polyborosiloxane modified polyaspartic acid ester, 15 to 30 parts of titanium dioxide, 0.2 to 1.0 parts of dispersant, 0.2 to 1.0 parts of defoaming agent, 0.2 to 1.0 parts of leveling agent, and 1.0 to 2.0 parts of anti-settling agent.

10. The polyurea coating according to claim 8 or 9, characterized in that: The isocyanate structural component includes at least one of toluene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate and hexamethylene diisocyanate.

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