Polysiloxane aspartate resin, polyurea coating and preparation method of polysiloxane aspartate resin and polyurea coating

Abstract

The invention belongs to the field of high polymer material synthesis and high polymer coatings, and provides a polysiloxane aspartic acid ester resin, a polyurea coating and a preparation method thereof.1, 4-cyclohexane diamine with cis-trans isomerism is adopted as a primary amino compound to be subjected to a Michael addition reaction with allyl-terminated siloxane, and the polysiloxane aspartic acid ester resin is obtained; the polysiloxane aspartic acid ester resin with a new structure is obtained, and the polysiloxane aspartic acid ester resin can react with an isocyanate curing agent to obtain a polyurea coating. Compared with the prior art, the addition reaction efficiency and the surface drying and hard drying time in the subsequent application process can be regulated and controlled by adjusting the cis-trans isomerization proportion of the 1, 4-cyclohexane diamine, meanwhile, the hydrophobicity, the water resistance, the corrosion resistance and other performance of the polyurea coating can be remarkably improved through introduction of the organic silicon component, the reaction process is simple and efficient, and the application range is wide. Good application and popularization prospects are realized.

Description

Technical Field

[0001] The invention belongs to the field of polymer material synthesis and polymer coatings, and in particular relates to a polysiloxane aspartic acid ester resin and a polyurea coating and a preparation method thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] The development of polyurea can be divided into three stages: aromatic polyurea, conventional aliphatic polyurea and aspartic polyurea. Polyaspartic acid ester polyurea is the third generation of new polyurea system after aromatic polyurea and aliphatic polyurea. It is a new type of aliphatic, slow-reacting, high-performance polyurea product with excellent comprehensive performance, weather resistance, aging resistance, convenient construction, strong adhesion, high elasticity, low temperature resistance, strong acid and alkali resistance. It is widely used in industrial coatings, waterproof materials, adhesives (seaming agents), structural materials and other fields. Although aspartic polyurea has better performance than other polyurea products, the current aspartic polyurea product structure is relatively simple, and product adjustments are often limited to the adjustment of construction performance, while performance optimization is still needed in some fields with high requirements such as anti-corrosion and waterproofing.

[0004] Polysiloxane has unique properties, such as extremely low glass transition temperature and surface energy, good hydrophobicity, good thermal stability and antioxidant capacity, high air permeability, excellent corrosion resistance, excellent biocompatibility, good insulation and low solubility parameter. These unique excellent properties make polysiloxane very widely used in coatings, textiles, electronic devices, liquid crystals, bionics, pharmaceutical materials, etc. However, polysiloxane has problems such as low mechanical strength and poor adhesion, which limits its application range.

[0005] In view of the respective performance advantages of polyurea resin and polysiloxane materials, there have been studies on the combination or modification of the two. However, in existing studies, amino-terminated polysiloxane is generally used to replace the commonly used diprimary amine and diethyl maleate for reaction preparation. Although this method introduces a siloxane structure into the system, the siloxane is actually in the main chain of the molecular structure and cannot fully exert the performance advantages of the silicone component. For example, in patent CN113861816B, hydroxy silicone oil is reacted with diethyl maleate to synthesize dipolysiloxane maleate, and then reacted with primary amine to prepare polyaspartic acid ester. This technical solution has complex reactions, and the conversion rate of each step is difficult to guarantee. In addition, the reaction of this structure with the curing agent will lead to slow reaction and long actual drying time due to excessive steric hindrance. There are also studies that use epoxy-containing polysiloxanes to react with conventional asparagus polyurea resins to introduce siloxane segments. However, the epoxy groups react with the primary or secondary amino groups in the asparagus polyurea resin to form hydroxyl functional groups. When reacting with isocyanate curing agents later, the ratio and cross-linking structure will change, affecting the performance of the coating. In addition, in the existing technical solutions related to asparagus polyurea resins, 4,4-diaminodicyclohexylmethane or 3,3-dimethyl-4,4-diaminodicyclohexylmethane is generally used to react with maleic acid diesters. This traditional system has the problem of low reaction efficiency. It generally requires a reaction of more than 24 hours to increase the conversion rate. In some application directions, it is necessary to adjust the parameters such as the application period and gel time by compounding the two products, which is relatively complicated. Summary of the invention

[0006] In order to solve the above problems, the present invention provides a polysiloxane aspartic acid ester resin and a polyurea coating and a preparation method thereof. The present invention develops an aspartic acid resin with a new structure, which can not only achieve the superposition effect of the excellent properties of aspartic acid polyurea and polysiloxane, but also significantly improve the hardness, water resistance, corrosion resistance and other properties compared with the traditional aspartic acid polyurea coating, and can also optimize the synthesis and use process of aspartic acid polyurea resin, improve the reaction degree through the raw material components, simplify the reaction operation, and is conducive to expanding the application field of aspartic acid ester resin materials.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides a polysiloxane aspartic acid ester resin, the structure of which is shown in Formula I, Formula II or Formula III;

[0009]

[0010] Among them, R1 is -H or -CH3, R2 is -CH3, -CH2CH3 or -CH(CH3)2, and n is an integer from 1 to 10.

[0011] The second aspect of the present invention provides a method for preparing the above-mentioned polysiloxane aspartic acid ester resin, comprising:

[0012] Using primary amino compounds and allyl-terminated siloxane as raw materials, a Michael addition reaction is carried out to obtain polysiloxane aspartic acid ester resin;

[0013] The primary amino compound is a mixture of cis and trans isomers of 1,4-cyclohexanediamine, and the molar ratio of cis isomer to trans isomer is 9:1 to 1:9. The resin reaction activity and polyurea coating performance can be adjusted according to the ratio of cis and trans isomers of 1,4-cyclohexanediamine; the ratio of cis isomer to trans isomer of 1,4-cyclohexanediamine can also be adjusted according to the requirements of resin reaction activity and coating construction.

[0014] In a preferred embodiment, the ratio of cis-isomer to trans-isomer of 1,4-cyclohexanediamine is controlled to be 9:1 to 7:3, so that resin and coating products with low reactivity, long surface drying time and gel time can be prepared.

[0015] In a preferred embodiment, the ratio of cis-isomer to trans-isomer of 1,4-cyclohexanediamine is controlled to be 4:6 to 1:9, so that resin and coating products with high reactivity, short surface drying time and gel time can be prepared.

[0016] In some embodiments, the allyl-terminated siloxane is selected from one of allyltrimethoxysilane, allyltriethoxysilane, allyltriisopropoxysilane, methylallyltrimethoxysilane, methylallyltriethoxysilane, methylallyltriisopropoxysilane, monoallyl-terminated polydimethylsiloxane, and monomethylallyl-terminated polydimethylsiloxane;

[0017] In some embodiments, the molecular weight of the monoallyl-terminated polydimethylsiloxane and the monomethylallyl-terminated polydimethylsiloxane are both 150-900 g / mol;

[0018] In some embodiments, the molar ratio of the primary amino compound to the allyl-terminated siloxane is 1:2 to 1:2.5.

[0019] In some embodiments, the Michael addition reaction temperature between the primary amino compound and the allyl-terminated siloxane is 50-80°C;

[0020] In some embodiments, the Michael addition reaction time between the primary amino compound and the allyl-terminated siloxane is 6-12 hours.

[0021] More specifically, they include:

[0022] First, a measured amount of primary amino compound (1,4-cyclohexanediamine) is added into a reaction kettle, and then a measured amount of allyl-terminated siloxane is added dropwise. After the dropwise addition is completed, the reaction is continued until the reaction is completed. After separation and purification, polysiloxane aspartic acid ester resin can be obtained.

[0023] The third aspect of the present invention provides a silicone-containing polyurea coating, which is cured and formed at room temperature in a two-component form, comprising: a resin component and a curing agent component;

[0024] The resin component is any one or a combination of two or more of the polysiloxane aspartic acid ester resins shown in Formula I, Formula II or Formula III.

[0025] That is, the resin may be a single resin of formula 1, formula 2, or formula 3, or a mixture of two or more resins of the same structure, and the weight ratio of the mixture may be any ratio.

[0026] In some embodiments, the curing agent component is an aliphatic isocyanate curing agent;

[0027] Preferably, the aliphatic isocyanate curing agent is a trimer or biuret form of hexamethylene diisocyanate, a trimer or biuret form of isophorone diisocyanate, or a trimer or biuret form of cyclohexane diisocyanate.

[0028] In some embodiments, the resin component may further include at least one of a diluent, a filler, a pigment, an anti-settling agent, an ultraviolet light absorber, and an antioxidant as required;

[0029] In some embodiments, a diluent may be added to the curing agent component as needed;

[0030] In some embodiments, the diluent is a solvent commonly used in traditional coatings that does not contain benzene, such as ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, ethyl 3-ethoxypropionate, etc., and the amount used is 10-30% of the mass of the curing agent;

[0031] In some embodiments, the ultraviolet absorber is at least one of 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, and 2(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole;

[0032] In some embodiments, the antioxidant is at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis(4-hydroxy-3,5-tert-butylphenylpropionate), 3,5-di-tert-butyl-4-hydroxyphenylpropionate octadecyl, triphenyl phosphite, diisodecyl pentaerythritol diphosphite, and dioctadecyl pentaerythritol phosphite;

[0033] In some embodiments, the filler is at least one of calcium carbonate, talc, titanium dioxide, silicon powder, and barium sulfate;

[0034] In some embodiments, the anti-settling agent is at least one of polyoxyethylene fatty alcohol sulfate, polyglycol ether, fumed silica, kaolin, and attapulgite.

[0035] In some embodiments, the ratio of the total NH equivalent in the resin component to the total NCO equivalent in the curing agent component is [NH] / [NCO]=1:1.05 to 1:1.08.

[0036] In some embodiments, the method for preparing the silicone-containing polyurea coating may be performed in the following order:

[0037] ① Weigh a certain amount of aliphatic isocyanate trimer, add a calculated amount of diluent and mix well to obtain the curing agent component.

[0038] ② The above-mentioned resin component (component A) and curing agent component (component B) are weighed and mixed according to the ratio of the total NH equivalent in the resin component A to the total NCO equivalent in the curing agent component B, that is, [NH] / [NCO] = 1:1.05 to 1:1.08, and the coating film is evaluated after sufficient mixing.

[0039] The fourth aspect of the present invention provides the above-mentioned polysiloxane aspartic acid ester resin, the polysiloxane aspartic acid ester resin prepared by the above-mentioned method, and the use of the above-mentioned silicone-containing polyurea coating in the preparation of industrial coatings, waterproof materials, adhesives, and structural materials.

[0040] Beneficial Effects of the Invention

[0041] (1) The present invention uses 1,4-cyclohexanediamine as a primary amine raw material to prepare polysiloxane aspartic acid ester resin and polyurea coating. The reactivity and usability of the obtained resin are controlled by adjusting the cis-trans ratio of 1,4-cyclohexanediamine to meet the needs of different construction requirements. There is no need to mix and compound polyaspartic acid esters of various systems such as 4,4-diaminodicyclohexylmethane or 3,3-dimethyl-4,4-diaminodicyclohexylmethane as in existing polyurea products.

[0042] (2) The present invention uses allyl siloxane monomers to react with 1,4-cyclohexanediamine to introduce siloxane structures into polyaspartic acid esters. The raw materials are easily available and do not require complicated preparation processes. In addition, compared with commonly used monomers such as diethyl maleate, allyl siloxane monomers have high reactivity and high reaction efficiency. When combined with 1,4-cyclohexanediamine, a high conversion rate can be obtained in a relatively short time. No complicated post-treatment such as molecular distillation is required, and production efficiency is significantly improved.

[0043] (3) The polysiloxane aspartic acid ester resin and polyurea coating provided by the present invention have a new structure, which can combine polysiloxane with polyurea to achieve the superposition effect of the performance advantages of the two, and can improve the coating hardness, hydrophobicity and waterproofness, corrosion resistance, chemical resistance and other properties of traditional polyurea, while meeting the requirements of construction applications for application period, actual drying time, etc.

[0044] (4) The preparation method of the present invention is simple, practical and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0046] Figure 1 This is the infrared spectrum of the reaction product of Example 6 of the present invention. DETAILED DESCRIPTION

[0047] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0048] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0049] Example 1

[0050] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 8:2 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 60°C, then drop 568.40g of allyltrimethoxysilane into the reaction bottle, keep the temperature not exceeding 70°C, control all the allyltrimethoxysilane to be added within 40min, keep the temperature at 70°C and continue the reaction for 8h. After the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 2h, and cool to 40°C to obtain the product. The product after the reaction is completed uses a potentiometric titrator to test the residual primary amine value in the system to be 0.21mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of allyltrimethoxysilane have basically completed the reaction.

[0051] Example 2

[0052] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 5:5 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 50°C, then drop 596.8g of allyltrimethoxysilane into the reaction bottle, keep the temperature not exceeding 65°C, control all the allyltrimethoxysilane to be added within 50min, keep the temperature at 65°C and continue the reaction for 7h. After the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 2h, and cool to 40°C to obtain the product. The product after the reaction is completed uses a potentiometric titrator to test the residual primary amine value in the system to be 0.19mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of allyltrimethoxysilane have basically completed the reaction.

[0053] Example 3

[0054] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of cis-isomer to trans-isomer of 2:8, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen unobstructed. Heat to 50°C, then drop 591.15g of allyltrimethoxysilane into the reaction bottle, keep the temperature not exceeding 65°C, control all the allyltrimethoxysilane to be added within 50min, keep the temperature at 65°C and continue to react for 6h. After the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 2h, and cool to 40°C to obtain the product. The product after the reaction is completed uses a potentiometric titrator to test the residual primary amine value in the system to be 0.17mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of allyltrimethoxysilane have basically completed the reaction.

[0055] Example 4

[0056] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 4:6 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 50°C, then drop 751.58g of allyltriethoxysilane into the reaction bottle, keep the temperature not exceeding 70°C, control all the allyltriethoxysilane to be added within 50min, keep the temperature at 70°C and continue the reaction for 8h. After the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for 3h of devolatilization, and cool to 40°C to obtain the product. The product after the reaction is completed uses a potentiometric titrator to test the residual primary amine value in the system to be 0.22mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of allyltriethoxysilane have basically completed the reaction.

[0057] Example 5

[0058] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 6:4 between cis-isomer and trans-isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 55°C, then drop 799.25g of methylallyl triethoxysilane into the reaction bottle, keep the temperature not exceeding 75°C, control all methylallyl triethoxysilane to be added within 60min, keep the temperature at 75°C and continue the reaction for 8h. After the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for 3h of devolatilization, and cool to 40°C to obtain the product. The product after the reaction is completed uses a potentiometric titrator to test the residual primary amine value in the system to be 0.16mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of methylallyl triethoxysilane have basically completed the reaction.

[0059] Example 6

[0060] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 7:3 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 60°C, then drop 1156.15g of monoallyl-terminated polydimethylsiloxane with a molecular weight of 322g / mol into the reaction bottle, keep the temperature not exceeding 75°C, control all monoallyl-terminated polydimethylsiloxane to be added within 80min, keep the temperature at 75°C and continue the reaction for 9h. After the reaction, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 3h, and cool to 40°C to obtain the product. The residual primary amine value in the product after the reaction was tested by a potentiometric titrator was 0.17 mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of the monoallyl-terminated polydimethylsiloxane were basically completely reacted.

[0061] Example 7

[0062] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 3:7 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 50°C, then drop 1575g of monomethylallyl-terminated polydimethylsiloxane with a molecular weight of 409g / mol into the reaction bottle, keep the temperature not exceeding 70°C, control all monomethylallyl-terminated polydimethylsiloxane to be added within 100min, keep the temperature at 70°C and continue the reaction for 11h. After the reaction, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 3h, and cool to 40°C to obtain the product. The residual primary amine value in the product after the reaction was tested by potentiometric titrator was 0.15 mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of monomethylallyl-terminated polydimethylsiloxane were basically completely reacted.

[0063] Example 8

[0064] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 5:5 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen unobstructed. Heat to 50°C, then drop 930g of monoallyl-terminated polydimethylsiloxane with a molecular weight of 629g / mol into the reaction bottle, keep the temperature not exceeding 60°C, control all monoallyl-terminated polydimethylsiloxane to be added dropwise within 60min, keep the temperature at 60°C and continue the reaction for 1h, then drop 186.10g of allyltriethoxysilane into the reaction bottle, control all allyltriethoxysilane to be added dropwise within 20min, then keep the temperature at 70°C and continue the reaction for 10h, after the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 3h, and cool to 40°C to obtain the product. The residual primary amine value in the product after the reaction was tested by potentiometric titrator was 0.10 mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bonds of monoallyl-terminated polydimethylsiloxane and allyltriethoxysilane were basically completely reacted.

[0065] Example 9

[0066] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 4:6 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen unobstructed. Heat to 50°C, then drop 513g of monomethylallyl-terminated polydimethylsiloxane with a molecular weight of 557g / mol into the reaction bottle, keep the temperature not exceeding 60°C, control all monoallyl-terminated polydimethylsiloxane to be added dropwise within 60min, keep the temperature at 60°C and continue the reaction for 1h, then drop 182.50g of allyl triisopropoxy into the reaction bottle, control all allyl triisopropoxy silane to be added dropwise within 20min, then keep the temperature at 70°C and continue the reaction for 10h, after the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 3h, and cool to 40°C to obtain the product. The residual primary amine value in the product after the reaction was tested by potentiometric titrator was 0.16 mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bonds of monomethylallyl-terminated polydimethylsiloxane and allyltriisopropoxysilane were basically completely reacted.

[0067] Comparative Example 1

[0068] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 4,4'-diaminodicyclohexylmethane, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 60°C, then drop 409.25g of diethyl maleate into the reaction bottle, keep the temperature not exceeding 75°C, control all the diethyl maleate to be added within 40min, keep the temperature at 75°C and continue the reaction for 24h. After the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 10h, and cool to 40°C to obtain the product. The product after the reaction was completed was tested using a potentiometric titrator, and the value of the remaining primary amine in the system was 40.21 mg / g, indicating that the primary amine group of 4,4'-diaminodicyclohexylmethane and the carbon-carbon double bond of diethyl maleate had not yet reacted completely. After the obtained product was allowed to stand for another week, the value of the remaining primary amine in the system was 0.82 mg / g using a potentiometric titrator, indicating that the primary amine group of 4,4'-diaminodicyclohexylmethane and the carbon-carbon double bond of diethyl maleate had mostly reacted.

[0069] Comparative Example 2

[0070] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 200g of 1,4-cyclohexanediamine with a mass ratio of 4:6 between cis isomer and trans isomer, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen flowing. Heat to 60°C, then drop 753.92g of diethyl maleate into the reaction bottle, keep the temperature not exceeding 75°C, control all diethyl maleate to be added within 80min, keep the temperature at 75°C and continue the reaction for 24h. After the reaction, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 10h, and cool to 40°C to obtain the product. The product after the reaction was completed was tested using a potentiometric titrator and the remaining primary amine value in the system was 34.62 mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of diethyl maleate had not yet reacted completely. After the obtained product was allowed to stand for another week, the remaining primary amine value in the system was tested using a potentiometric titrator and was 0.75 mg / g, indicating that the primary amine group of 1,4-cyclohexanediamine and the carbon-carbon double bond of diethyl maleate had mostly reacted.

[0071] Comparative Example 3

[0072] In a glass flask equipped with a stirrer, a thermometer, a dropping funnel, a nitrogen tube and a reflux condenser, add 400g of double-end amino-terminated polydimethylsiloxane with a molecular weight of 750g / mol, start stirring, replace the air in the reaction bottle with nitrogen three times and keep the nitrogen unobstructed. Heat to 60°C, then add 193.50g of diethyl maleate dropwise to the reaction bottle, keep the temperature not exceeding 75°C, control all diethyl maleate to be added dropwise within 30min, keep the temperature at 75°C and continue the reaction for 24h. After the reaction is completed, use a vacuum pump to reduce the pressure to -0.1Mpa for devolatilization for 10h, and cool to 40°C to obtain the product. The product after the reaction was completed was tested using a potentiometric titrator and the value of the remaining primary amine in the system was 16.87 mg / g, indicating that the primary amine group of the double-end amino-terminated polydimethylsiloxane and the carbon-carbon double bond of diethyl maleate had not yet reacted completely. After the obtained product was allowed to stand for another week, the value of the remaining primary amine in the system was tested using a potentiometric titrator and was 0.90 mg / g, indicating that the primary amine group of the double-end amino-terminated polydimethylsiloxane and the carbon-carbon double bond of diethyl maleate had mostly completed the reaction.

[0073] Experimental Example: Preparation of Siloxane-Containing Polyurea Coating

[0074] Preparation of the resin component: First, 500 g of the resin prepared in the above Examples 1-9 (denoted as E1, E2 ... E9) and Comparative Examples 1-3 (denoted as C1, C2, C9) were weighed and added to a container; 1.75 g of an ultraviolet light absorber (2-hydroxy-4-methoxybenzophenone) and 1.75 g of an antioxidant (pentaerythritol tetrakis (4-hydroxy-3,5-tert-butylphenyl propionate)) were added and stirred thoroughly; 100 g of a diluent (ethyl acetate), 200 g of a filler (talc), and 15 g of an anti-settling agent (fumed silica) were added and stirred thoroughly, and then the stirring speed was increased. After high-speed dispersion for 30 minutes, the mixture was ground to a qualified fineness to obtain the resin component.

[0075] Preparation of curing agent component: Weigh 200g HDI trimer with NCO content of 21.8%, mix and disperse evenly with 35g diluent (ethyl acetate) to obtain curing agent component. After dilution, the average NCO content is 18.55%.

[0076] Preparation of coating film: prepare clean tinplate for coating film spraying. According to the formula ratio in Table 1, weigh the resin component A and the curing agent component B respectively and mix them evenly. Add appropriate amount of diluent to adjust the viscosity to suitable operation. Use air spray gun to spray evenly on the surface of tinplate. Control the film thickness to be 80-90 microns and the dry film thickness to be 50-60 microns. The wet film is left to stand at room temperature for 30 minutes for leveling and initial drying. It is placed at room temperature for 4 hours for curing. It can also be placed in an 80℃ blast oven for 30-60 minutes for curing to obtain a coating film containing siloxane polyurea coating. The drying time is tested during the curing process of the coating film. The performance test can be carried out after the coating film is matured for 24 hours.

[0077] Table 1 Coating formula ratio

[0078]

[0079]

[0080] The coating performance test is as follows:

[0081] Table 2 Coating performance test results

[0082]

[0083] It can be seen that compared with the traditional polyurea coating (Comparative Example 1), the polyurea coating prepared by the polysiloxane aspartic acid ester resin with a new structure in the present invention has excellent comprehensive performance, and the addition reaction efficiency and the surface drying and actual drying time of the polyurea coating can be regulated by adjusting the cis-trans isomerization ratio of 1,4-cyclohexanediamine. At the same time, the introduction of the silicone component can significantly improve the hydrophobicity, water resistance, corrosion resistance and hardness of the polyurea coating.

[0084] From the comparison of Examples 1-9 with Comparative Examples 2 and 3, it can be seen that compared with the polyurea coating "containing no silicone component" or "without silicone in the side chain", the polyurea coating of the present invention has better hydrophobicity, water resistance, corrosion resistance and hardness.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A polysiloxane aspartic acid ester resin, characterized in that: Its structure is shown in Formula I, Formula II or Formula III; Among them, R1 is -H or -CH3, R2 is -CH3, -CH2CH3 or -CH(CH3)2, and n is an integer from 1 to 10.

2. A method for preparing a polysiloxane aspartic acid ester resin as claimed in claim 1, characterized in that: include: Using primary amino compounds and allyl-terminated siloxane as raw materials, a Michael addition reaction is carried out to obtain polysiloxane aspartic acid ester resin; The primary amino compound is a mixture of cis and trans isomers of 1,4-cyclohexanediamine, and the molar ratio of the cis isomer to the trans isomer is 9:1 to 1:9, 9:1 to 7:3 or 4:6 to 1:

9.

3. The method for preparing the polysiloxane aspartic acid ester resin according to claim 2, characterized in that: The allyl-terminated siloxane is selected from one of allyltrimethoxysilane, allyltriethoxysilane, allyltriisopropoxysilane, methylallyltrimethoxysilane, methylallyltriethoxysilane, methylallyltriisopropoxysilane, monoallyl-terminated polydimethylsiloxane, and monomethylallyl-terminated polydimethylsiloxane.

4. The method for preparing the polysiloxane aspartic acid ester resin according to claim 2, characterized in that: The molecular weights of the monoallyl-terminated polydimethylsiloxane and the monomethylallyl-terminated polydimethylsiloxane are both 150-900 g / mol.

5. The method for preparing the polysiloxane aspartic acid ester resin according to claim 2, characterized in that: The molar ratio of the primary amino compound to the allyl-terminated siloxane is 1:2 to 1:2.

5.

6. The method for preparing the polysiloxane aspartic acid ester resin according to claim 2, characterized in that: The Michael addition reaction temperature between the primary amino compound and the allyl-terminated siloxane is 50-80°C; Alternatively, the Michael addition reaction time between the primary amino compound and the allyl-terminated siloxane is 6-12 hours.

7. A silicone-containing polyurea coating, characterized in that: include: A resin component and a curing agent component; The resin component is any one or a combination of two or more of the polysiloxane aspartic acid ester resins represented by formula I, formula II or formula III in claim 1.

8. The silicone-containing polyurea coating according to claim 7, wherein: The curing agent component is an aliphatic isocyanate curing agent; Alternatively, the aliphatic isocyanate curing agent is a trimer or biuret form of hexamethylene diisocyanate, a trimer or biuret form of isophorone diisocyanate, or a trimer or biuret form of cyclohexane diisocyanate.

9. The silicone-containing polyurea coating according to claim 7, characterized in that: At least one of a diluent, a filler, a pigment, an anti-settling agent, an ultraviolet light absorber, and an antioxidant is further added to the resin component; Or, a diluent is further added to the curing agent component; Or, the diluent is a solvent that does not contain benzene, and the amount used is 10-30% of the mass of the curing agent; Or, the ultraviolet absorber is at least one of 2-hydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, and 2(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole; Or, the antioxidant is at least one of 2,6-di-tert-butyl-4-methylphenol, pentaerythritol tetrakis(4-hydroxy-3,5-tert-butylphenylpropionate), 3,5-di-tert-butyl-4-hydroxyphenylpropionate octadecyl, triphenyl phosphite, diisodecyl pentaerythritol diphosphite, and dioctadecyl pentaerythritol phosphite; Or, the filler is at least one of calcium carbonate, talc, titanium dioxide, silicon powder, and barium sulfate; Or, the anti-settling agent is at least one of polyoxyethylene fatty alcohol sulfate, polyglycol ether, fumed silica, kaolin, and attapulgite; Alternatively, the mixture is mixed at a ratio of [NH] / [NCO] of the total NH equivalent in the resin component to the total NCO equivalent in the curing agent component of 1:1.05 to 1:1.

08.

10. Use of the polysiloxane aspartic acid ester resin according to claim 1, the polysiloxane aspartic acid ester resin prepared by the method according to any one of claims 2 to 6, and the silicone-containing polyurea coating according to any one of claims 7 to 9 in the preparation of industrial coatings, waterproof materials, adhesives, and structural materials.

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