A modified silicone resin, and a method for preparing and using the same

Abstract

The application discloses a modified organic silicon resin and a preparation method and application thereof. The preparation method comprises the following steps: firstly, carrying out a chain extension reaction on an organic silicon resin by using a chain extender; and secondly, adding a crosslinking agent to carry out a crosslinking reaction, so as to prepare the modified organic silicon resin by introducing a ureide formic acid ester through the chain extension reaction of the amino silane on the organic silicon resin in the first step and through the crosslinking reaction in the second step. The modified organic silicon resin provided by the application is used for preparing high-temperature-resistant paint, can meet the requirement of high-temperature-resistant protection performance, and has excellent performances such as fast drying speed, high viscosity, good flexibility, good adhesion and anti-flowing performance.

Description

Technical Field

[0001] This invention relates to the field of organosilicon high-temperature resistant coating technology, specifically to a modified organosilicon resin and its preparation method and application. Background Technology

[0002] The main chain of silicone resin molecules contains a large number of —Si—O—Si— inorganic structures. Compared with organic resins with carbon chains as the backbone (the bond energy of Si—O bonds is as high as 452 kJ / mol, far higher than that of C—C bonds (347 kJ / mol) and C—O bonds (351 kJ / mol)), the main chain of silicone resin is more stable. After the side groups are oxidized and decomposed by heat, silicone resin forms a highly cross-linked and more stable spatial network structure, which can prevent further breakage of the main chain. Therefore, silicone resin has the characteristics of good thermal stability, high thermal decomposition temperature, and excellent weather resistance. It can be used as a film-forming material for high-temperature coatings and is widely used for protection of high-temperature furnace outer walls, steam turbine blades, automobile exhaust pipes, air heat exchanger surfaces, and jet engine exhaust nozzles.

[0003] Organosilicon resins contain a large number of methyl and phenyl groups in their side chains. Increasing the phenyl group content is beneficial for improving properties such as temperature resistance, mechanical properties, adhesion, and gloss. However, methyl and phenyl groups have low electronegativity, resulting in weak intermolecular forces and low resin viscosity. Coatings prepared with these resins tend to dry slowly, settle easily, and sag. The low electronegativity also leads to poor adhesion of the coating to the substrate and poor film flexibility.

[0004] Therefore, in recent years, researchers have conducted extensive research and development work on organosilicon resin coatings. For example, the patent "Preparation and Application Method of an Organosilicon-Polyurea Self-Laminating Coating" (CN107298930A) addresses the problems of poor interlayer adhesion and low construction efficiency caused by multi-layer construction in the external protective coating of concrete buildings. It prepares a two-component protective coating by using an organosilicon-modified polyurethane curing agent component and a silicone-containing resin component. The organosilicon resin component and the polyurea matrix material form a gradual "transition layer" during the coating curing process, resulting in an organosilicon-polyurea self-laminating protective coating with excellent substrate adhesion and overall weather resistance. Another patent, "A Composite Organosilicon Resin and High-Temperature Resistant Coating" (CN112358617A), adds an alkoxy coupling agent monomer containing epoxy, polyester, and acrylic groups to the organosilicon resin synthesis process. This monomer co-hydrolyzes and polycondenses with the alkoxysilane monomer to form a high-temperature resistant composite organosilicon resin with Si-O-Si bonds as the main component and flexible segments as auxiliary components. During the sol-gel process, inorganic nano-sols are also added for doping, forming a honeycomb protective structure and improving the resin's high-temperature resistance. Performance; Patent "An Organosilicon-Modified PAE Polyurea Coating" (CN113861816A) introduces polysiloxane groups onto the side chains of polyaspartic ester and isocyanate curing agent, resulting in a PAE polyurea coating with good leveling properties, high corrosion resistance, high temperature resistance, and high coating strength; Patent "A Preparation Method of Organosilicon-Modified Polyurea" (CN114276508A) prepolymerizes polyaspartic ester with isocyanate monomer and then adds an amino coupling agent to modify hydroxyl silicone oil, resulting in... Organosilicon-polyurea composite materials effectively improve their adhesion to cement mortar and concrete substrates. The patent "An Organosilicon Modified Polyurea Polyurethane Antifouling Coating and Its Preparation Method and Application" (CN118240463A) is composed of isocyanate-terminated polysiloxane reacted sequentially with 4,4'-dihydroxydiphenyl disulfide and dimethylglyoxime, followed by the addition of tannic acid. This coating has excellent mechanical properties and static antifouling ability, as well as high adhesive strength, and has good application prospects in the field of marine antifouling.

[0005] As can be seen from the patents disclosed above, the current polyurea-modified silicone resin is mainly a two-component coating system prepared from polyaspartic acid ester and hydroxyl silicone oil. Two-component coatings require mixing and the construction steps are complicated. In addition, the existing technology does not have a systematic solution to comprehensively improve the performance of silicone resins, which has problems such as low viscosity, slow drying, poor flexibility and poor adhesion. Summary of the Invention

[0006] The main objective of this invention is to provide a modified organosilicon resin, its preparation method, and its application, in order to overcome the shortcomings of the prior art.

[0007] To achieve the aforementioned objectives, the technical solution adopted by this invention includes: One aspect of the present invention provides a method for preparing a modified organosilicon resin, comprising: first, subjecting the organosilicon resin to a chain extender for a chain extension reaction, and then adding a crosslinking agent for a crosslinking reaction to obtain the modified organosilicon resin.

[0008] Another aspect of the present invention provides a modified organosilicon resin prepared by the aforementioned preparation method.

[0009] Another aspect of the present invention provides the application of the aforementioned modified silicone resin in the field of coatings.

[0010] Compared with the prior art, the technical solution of the present invention has at least the following advantages: The preparation method provided by this invention first involves a chain extension reaction between aminosilane and organosilicon resin in the first step, followed by a crosslinking reaction to introduce urea carbamate, thereby obtaining a modified organosilicon resin. This method comprehensively solves the problems of poor application performance of organosilicon resin in coatings, such as low viscosity, poor adhesion, poor flexibility, slow drying speed, and easy sagging. Furthermore, by adding additives to react with amine groups, the activity of the amine groups is reduced, effectively improving product quality and batch-to-batch stability. Detailed Implementation

[0011] The invention will be more fully understood by reading the following detailed description. However, it should be understood that the detailed description disclosed below is merely exemplary of the invention, which can be embodied in various forms. Therefore, the specific functional details disclosed herein should not be construed as limiting, but rather as the basis for the claims and as a representative basis for teaching those skilled in the art to employ the invention in different ways in any suitable detailed embodiment.

[0012] As one aspect of the technical solution of the present invention, a method for preparing a modified organosilicon resin includes: first, subjecting the organosilicon resin to a chain extender reaction, and then adding a crosslinking agent to a crosslinking reaction to obtain the modified organosilicon resin.

[0013] In some embodiments, the preparation method includes: first mixing the organosilicon resin with a first solvent, heating, adding a chain extender to carry out a chain extension reaction, then adding a crosslinking agent and, selectively adding or not adding a second solvent, carrying out a crosslinking reaction to obtain the modified organosilicon resin.

[0014] In some preferred embodiments, the mass ratio of the combination of the silicone resin, chain extender, crosslinking agent, first solvent and second solvent is (20-50):(1-25):(1-10):(30-80).

[0015] In some preferred embodiments, the silicone resin includes, but is not limited to, any one or a combination of two of methylphenyl silicone resin and polydimethylsiloxane resin.

[0016] In some more preferred embodiments, the methylphenyl silicone resin is prepared by mixing methylphenyl dichlorosilane, dimethyl dichlorosilane, diphenyl dichlorosilane and water.

[0017] In some preferred embodiments, the first solvent includes, but is not limited to, any one or a combination of two or more of methanol, ethanol, isopropanol, n-butanol, propylene glycol methyl ether, ethylene glycol monobutyl ether, benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, acetone, butanone, cyclohexanone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate.

[0018] In some preferred embodiments, the second solvent includes, but is not limited to, any one or a combination of two or more of methanol, ethanol, isopropanol, n-butanol, propylene glycol methyl ether, ethylene glycol monobutyl ether, benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, acetone, butanone, cyclohexanone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate.

[0019] In some preferred embodiments, the chain extender includes, but is not limited to, any one or a combination of two or more of 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane, 3-diethylenetriaminepropylmethyldimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldiethoxysilane, and 3-diethylenetriaminepropylmethyldiethoxysilane.

[0020] In some preferred embodiments, the preparation method further includes: selectively adding or not adding a first additive while adding a chain extender, wherein the first additive includes, but is not limited to, any one or a combination of two or more of benzoic acid, formic acid, acetic acid, propionic acid, butyric acid, lauric acid, glycidyl tert-carbonate, phenyl glycidyl ether, benzyl glycidyl ether, butyl glycidyl ether, C12, C14 glycidyl ether, diethyl maleate, butyl maleate, and acrylonitrile.

[0021] In some more preferred embodiments, the mass ratio of the first additive to the chain extender is 0.5-2:1.

[0022] In the preparation process of this invention, since the reaction of the amine group with isocyanate is difficult to control due to its high reactivity, a first additive is added to react with the amine group to reduce its reactivity. For example, benzoic acid, formic acid, butyric acid, lauric acid, etc., undergo a reverse amidation reaction with the primary amine group in N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane or N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, reducing the trifunctional amine to a monofunctional amine, while simultaneously reducing the reactivity of the amine group to prevent gelation. For example, glycidyl tert-carbonate, benzyl glycidyl ether, etc., reduce the functionality and reactivity of the amine group through ring-opening polymerization with the amine group. Furthermore, diethyl maleate, dibutyl maleate, acrylonitrile, etc., reduce the functionality and reactivity of the amine group through Michael addition reaction.

[0023] In some preferred embodiments, the crosslinking agent includes, but is not limited to, any one or a combination of two or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and diphenylmethane diisocyanate.

[0024] In some preferred embodiments, the preparation method further includes: selectively adding or omitting a second additive while adding a crosslinking agent, wherein the second additive includes, but is not limited to, any one or a combination of two or more of bismuth neodecanoate, bismuth naphthenate, and bismuth isooctanoate. The complexation reaction between amine groups and bismuth further increases the molecular weight of the resin, improves the drying speed of the coating film, and enhances the flexibility of the coating film.

[0025] In some more preferred embodiments, the mass ratio of the second additive to the chain extender is 0.5-2:1.

[0026] In some preferred embodiments, the preparation method includes: mixing the organosilicon resin with a first solvent, heating to 40-130°C under stirring, adding a chain extender, and carrying out the chain extension reaction.

[0027] In some more preferred embodiments, the chain extension reaction is carried out at a temperature of 80-160°C for a duration of 0.5-5 hours.

[0028] In some preferred embodiments, the preparation method includes: after the chain extension reaction is completed, cooling to 30-80°C, adding a second solvent and a crosslinking agent, and carrying out the crosslinking reaction to obtain the modified organosilicon resin.

[0029] In some more preferred embodiments, the crosslinking reaction is carried out at a temperature of 30-100°C for a time of 0.5-5 hours.

[0030] In some more preferred embodiments, the crosslinking agent is added dropwise; further, the crosslinking agent is added dropwise over 0.5h-5h.

[0031] In some more specific embodiments, the preparation method of the modified organosilicon resin includes the following steps: adding organosilicon resin and a first solvent into a reaction vessel, heating to 40-130°C while stirring, adding a chain extender after the temperature stabilizes, maintaining the temperature at 80-160°C for 0.5-5 hours to carry out the chain extension reaction, cooling to 30-80°C after the chain extension reaction is completed, adding a second solvent, and starting to add a crosslinking agent dropwise for 0.5-5 hours after the temperature stabilizes, maintaining the temperature at 30-100°C for 0.5-5 hours to carry out the crosslinking reaction, thereby obtaining the modified organosilicon resin.

[0032] As another aspect of the technical solution of the present invention, it relates to the modified organosilicon resin prepared by the aforementioned preparation method.

[0033] As another aspect of the technical solution of the present invention, it also relates to the application of the aforementioned modified organosilicon resin in the field of coatings.

[0034] In some implementations, the coating includes, but is not limited to, high-temperature resistant coatings.

[0035] It should be noted that the preparation method of the modified organosilicon resin provided by the present invention is mainly based on a two-step reaction: the first step is to carry out a chain extension reaction of organosilicon resin with aminosilane. The chain extension reaction of aminosilane can increase the molecular weight of organosilicon resin, improve the drying speed and flexibility of the resin, and introduce amino functional groups to provide raw materials for the subsequent formation of urea carbamate; the second step is to introduce urea carbamate to improve the adhesion and workability of the resin.

[0036] Furthermore, in some embodiments, because the amine group is multifunctional, there is a risk of gelation during the reaction with the crosslinking agent isocyanate, affecting product quality stability. Moreover, the crosslinking methods of multifunctional amine groups and multifunctional isocyanates differ, resulting in variations in viscosity and performance between product batches, thus affecting batch-to-batch stability. To ensure process control and product quality stability, this invention incorporates a first additive that reacts with the amine group in the chain extender, such as an addition reaction between epoxy and amine groups, a Michael addition reaction between vinyl and amine groups, or an amidation reaction between carboxylic acid and amine groups, thereby reducing the activity of the amine group and improving product quality and batch-to-batch stability.

[0037] The present invention is further illustrated below by way of examples, but the invention is not limited to the scope of the examples described. All reagents and raw materials used in the following examples are commercially available, and test methods not specifically specified are generally performed under conventional conditions or according to the conditions recommended by the respective manufacturers.

[0038] Example 1 Weigh 20 parts by weight of methylphenyl silicone resin and 78 parts by weight of toluene and add them to a reaction vessel. While stirring, heat the mixture to 40°C. After the temperature stabilizes, add 1 part of N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane. Keep the mixture at 80°C for 0.5 hours, then cool it to 30°C. After the temperature stabilizes, start adding 1 part of hexamethylene diisocyanate dropwise over 0.5 hours until the addition is complete. After the addition is complete, keep the mixture at 30°C for 0.5 hours to obtain the modified silicone resin.

[0039] Example 2 Weigh out 50 parts by weight of methylphenyl silicone resin and 20 parts by weight of xylene and add them to a reaction vessel. Heat the mixture to 100°C while stirring. After the temperature stabilizes, add 10 parts by weight of 3-aminopropylmethyldimethoxysilane and keep it at 160°C for 5 hours. Cool the mixture down to 80°C and add 10 parts by weight of n-butanol as a solvent. After the temperature stabilizes, start adding 5 parts by weight of toluene diisocyanate dropwise over 5 hours. After the addition is complete, keep the mixture at 100°C for 5 hours to obtain the modified silicone resin.

[0040] Example 3 Weigh out 5 parts by weight of methylphenyldichlorosilane, 10 parts by weight of dimethyldichlorosilane, 15 parts by weight of diphenyldichlorosilane, 10 parts by weight of water, and 20 parts by weight of xylene and add them to a reaction vessel. Heat the mixture to 100°C while stirring. After the temperature stabilizes, add 10 parts by weight of 3-aminopropylmethyldiethoxysilane and 10 parts by weight of glycidyl tert-carbonate. Keep the mixture at 130°C for 5 hours. Cool the mixture to 80°C and add 10 parts by weight of n-butanol as a solvent. After the temperature stabilizes, start adding 10 parts by weight of hexamethylene diisocyanate dropwise over 5 hours until the addition is complete. After the addition is complete, keep the mixture at 70°C for 2 hours to obtain the modified organosilicon resin.

[0041] Example 4 Weigh out 5 parts by weight of methylphenyl dichlorosilane, 10 parts of dimethyl dichlorosilane, 11 parts of diphenyl dichlorosilane, 10 parts of water, and 20 parts of propylene glycol methyl ether acetate and add them to a reaction vessel. Heat the mixture to 100°C while stirring. After the temperature stabilizes, add 22 parts of N-(piperazinylethyl)-3-aminopropylmethyldiethoxysilane and 11 parts of butyl glycidyl ether. Keep the mixture at 120°C for 5 hours, then cool it to 80°C. Add 10 parts of trimethylbenzene as solvent. After the temperature stabilizes, start adding 3 parts of hexamethylene diisocyanate and 11 parts of bismuth neodecanoate dropwise. The addition is completed in 5 hours. After the addition is completed, keep the mixture at 60°C for 3 hours to obtain the modified organosilicon resin.

[0042] Example 5 Weigh out 30 parts by weight of methylphenyl silicone resin and 47 parts by weight of xylene and add them to a reaction vessel. Heat the mixture to 130°C while stirring. After the temperature stabilizes, add 10 parts by weight of N-(piperazinylethyl)-3-aminopropylmethyldiethoxysilane. Keep the mixture at 120°C for 3 hours. Cool the mixture to 40°C and add 10 parts by weight of trimethylbenzene as solvent. After the temperature stabilizes, start adding 3 parts by weight of diphenylmethane diisocyanate. The addition is completed in 1 hour. After the addition is completed, keep the mixture at 60°C for 1 hour to obtain the modified silicone resin.

[0043] Comparative Example 1 The difference compared to Example 1 is that the crosslinking agent hexamethylene diisocyanate was not added.

[0044] Comparative Example 2 Compared with Example 1, the difference is that the chain extender N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane was not added.

[0045] Comparative Example 3 Compared with Example 1, the difference is that hexamethylene diisocyanate trimer (HDI trimer) was selected as the crosslinking agent.

[0046] Comparative Example 4 Compared with Example 1, the difference is that 3-glycidyl etheroxypropylmethyldimethoxysilane was selected as the chain extender.

[0047] High-temperature resistant coatings were prepared using the modified silicone resins obtained in Examples 1-5, the silicone resins obtained in Comparative Examples 1-4, and competing silicone resins from the market. Reference formulations are shown in Table 1.

[0048] The modified silicone resins obtained in Examples 1-5, the silicone resins obtained in Comparative Examples 1-4, and the high-temperature resistant coatings prepared from competing silicone resins on the market were compared under the same conditions. The test performance data are shown in Tables 2 and 3.

[0049]

[0050]

[0051] As can be seen from the comparison data in Tables 2 and 3, the high-temperature resistant coatings made from the modified organosilicon resins of Examples 1-5 of this invention can all meet the requirements of high-temperature protection performance at 650℃*5 hours, and have excellent construction performance, with characteristics such as fast drying speed, high viscosity, good flexibility, good adhesion, and anti-sagging, showing obvious comprehensive performance advantages.

[0052] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0053] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. The application of a modified organosilicon resin in the preparation of high-temperature resistant coatings, characterized in that, The method for preparing the modified organosilicon resin includes: first, mixing the organosilicon resin with a first solvent and heating it to 40~130℃, adding a chain extender and a first additive to carry out a chain extension reaction; then adding a crosslinking agent and a selectable second solvent, and carrying out a crosslinking reaction at 30℃~100℃ to obtain the modified organosilicon resin. Wherein, the organosilicon resin is methylphenyl organosilicon resin; the chain extender is aminosilane; the crosslinking agent is isocyanate; the first additive includes any one or a combination of two or more of benzoic acid, formic acid, acetic acid, propionic acid, butyric acid, lauric acid, glycidyl tert-carbonate, phenyl glycidyl ether, benzyl glycidyl ether, butyl glycidyl ether, C12, C14 glycidyl ether, diethyl maleate, butyl maleate, and acrylonitrile; the mass ratio of the organosilicon resin, chain extender, crosslinking agent, first solvent and second solvent is (20-50):(1-25):(1-10):(30-80); and the mass ratio of the first additive to the chain extender is 0.5-2:

1.

2. The application according to claim 1, characterized in that, The methylphenyl organosilicon resin is prepared by mixing methylphenyl dichlorosilane, dimethyl dichlorosilane, diphenyl dichlorosilane and water.

3. The application according to claim 1, characterized in that: The first solvent includes any one or a combination of two or more of methanol, ethanol, isopropanol, n-butanol, propylene glycol methyl ether, ethylene glycol monobutyl ether, benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, acetone, butanone, cyclohexanone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate.

4. The application according to claim 1, characterized in that: The second solvent includes any one or a combination of two or more of methanol, ethanol, isopropanol, n-butanol, propylene glycol methyl ether, ethylene glycol monobutyl ether, benzene, toluene, xylene, trimethylbenzene, tetramethylbenzene, acetone, butanone, cyclohexanone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and propylene glycol methyl ether acetate.

5. The application according to claim 1, characterized in that, The chain extender includes any one or a combination of two or more of the following: 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldimethoxysilane, 3-diethylenetriaminepropylmethyldimethoxysilane, N-(piperazinylethyl)-3-aminopropylmethyldiethoxysilane, and 3-diethylenetriaminepropylmethyldiethoxysilane.

6. The application according to claim 1, characterized in that, The crosslinking agent includes any one or a combination of two or more of toluene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, and diphenylmethane diisocyanate.

7. The application according to claim 1, characterized in that... Also includes: While adding the crosslinking agent, a second additive may be selectively added or not added. The second additive includes any one or a combination of two or more of bismuth neodecanoate, bismuth naphthenate, and bismuth isooctanoate.

8. The application according to claim 7, characterized in that: The mass ratio of the second additive to the chain extender is 0.5-2:

1.

9. The application according to claim 1, characterized in that: The chain extension reaction is carried out at a temperature of 80-160℃ for 0.5-5 hours.

10. The application according to claim 1, characterized in that: The cross-linking reaction takes 0.5-5 hours.

11. The application according to claim 1, characterized in that: The crosslinking agent is added dropwise.

12. The application according to claim 11, characterized in that: The crosslinking agent is added dropwise over a period of 0.5-5 hours.

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