A method for producing a (meth)acryloxy silane oligomer and a uv-cured product thereof

Abstract

The application relates to the technical field of organic silicon materials and ultraviolet light curing, and discloses a preparation method of a (methyl) acryloxy silane oligomer and a UV cured product thereof. The method comprises the following steps: carrying out hydrolysis condensation reaction on KH-572 monomers, an alcohol solvent and a catalyst at 40-60 DEG C, and preparing KH-572 oligomers with a polymerization degree of 5-25 by controlling the hydrolysis conditions; and mixing the oligomers with methyl methacrylate and a photoinitiator according to a weight ratio of (60-70):(40-30):(1-3), and then carrying out ultraviolet light curing forming. The application solves the technical problem that the KH-572 monomers cannot be directly used for curing by controllable polymerization, and the obtained cured coating has the advantages of compact structure and controllable hydrophobicity. The preparation method is simple in process and easy for industrialized production.

Description

Technical Field

[0001] This invention belongs to the field of organosilicon materials and ultraviolet curing technology, specifically relating to an ultraviolet curing composition with a (meth)acryloyloxysilane oligomer of a specific structure as the key component. Background Technology

[0002] Ultraviolet (UV) curing technology has attracted much attention in the field of precision coating material preparation due to its high efficiency, energy saving, and environmental friendliness. The precision and stability of the molecular structure of oligomers in the UV-curing formulation directly determine the comprehensive performance of the final cured coating. Properties such as hydrophobicity, mechanical strength, and durability are largely determined by the molecular structure of the oligomers and the cross-linked network structure they form. In existing technologies, introducing organosilicon components has become an important technical direction to improve the heat resistance, flexibility, and surface properties of UV-cured coatings. However, this technical approach has a key bottleneck: the degree of polymerization of oligomers is generally low and their structure is uncontrollable. Chinese invention patent CN118388769A discloses a method for preparing alkoxysilane oligomers containing acyl groups through hydrolysis-condensation, but the product is a low-viscosity mixture with a degree of polymerization between 5 and 10. This low degree of polymerization means shorter molecular chains, which makes it difficult to form a sufficiently dense and stable three-dimensional network structure after UV curing, thus limiting further improvements in the mechanical strength, heat resistance, and long-term durability of the coating.

[0003] On the other hand, even if high-polymerization-degree oligomers are successfully synthesized, significant challenges remain if their photocuring behavior and coating mechanism are not sufficiently optimized. Traditional single-oligomer UV curing systems often result in microscopic inhomogeneity of the crosslinking network due to the limited functional group reaction types and restricted molecular chain mobility. This inhomogeneity leads to excessive internal stress in the coating, insufficient flexibility, and increased surface defects caused by curing shrinkage, ultimately weakening hydrophobic properties, adhesion, and overall appearance.

[0004] Therefore, existing technologies have not yet provided a systematic solution that can both construct a robust network framework using high-polymerization-degree oligomers and improve the network microstructure through optimized copolymerization strategies, thereby achieving a synergistic improvement in coating hydrophobicity, mechanical properties, and preparation reproducibility. This application aims to provide a new technical solution to overcome the deficiencies in the aforementioned existing technologies. Summary of the Invention

[0005] To overcome the limitations of existing technologies where the low polymerization rate of silane oligomers makes it difficult to form a sufficiently dense and stable three-dimensional network structure after photocuring, thus restricting further improvements in the mechanical strength, heat resistance, and long-term durability of coatings, this invention provides a 3-methacryloyloxypropylmethyldimethoxysilane (KH-572) oligomer with a high degree of polymerization and uniform structure, and its UV-cured composite coating, to achieve a dense coating structure, low internal stress, strong adhesion, and precise control over the coating's hydrophobicity and other surface properties.

[0006] The present invention adopts the following technical solution: A method for preparing a (meth)acryloyloxysilane oligomer (KH-572): S1. Add 3-methacryloxypropylmethyldimethoxysilane, methanol, high-efficiency polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine nitroxide radical (polymerization inhibitor ZM-701) and concentrated hydrochloric acid to the reaction vessel, mix well, and heat to 40~60℃. Add deionized water dropwise to the mixture at a uniform rate, and control the dropwise addition time to 1~3h. S2. After the addition is complete, raise the temperature to 60~80℃ and maintain it for 4~6h; then remove the methanol solvent and the methanol generated in the reaction by vacuum distillation; after the distillation is completed, cool to room temperature to obtain (meth)acryloyloxysilane oligomer (KH-572).

[0007] The main reaction equations involved in this invention are as follows: In step S1, the mass ratio of methanol to 3-methacryloxypropylmethyldimethoxysilane is 10~30:100; the concentration of hydrochloric acid is 12mol / L, and the mass ratio of hydrochloric acid to 3-methacryloxypropylmethyldimethoxysilane is 1~5:100; the mass ratio of polymerization inhibitor ZM-701 to 3-methacryloxypropylmethyldimethoxysilane is 0.05~1.0:100; and the molar ratio of 3-methacryloxypropylmethyldimethoxysilane to deionized water is 1:0.7~1.2. In step S2, the vacuum degree of the reduced pressure distillation is -0.1 to -0.07 MPa.

[0008] A high-performance UV-curable compound, made from the following components in parts by weight: The above-mentioned KH-572 oligomer: 60~70 parts by weight; MMA: 30~40 parts by weight; photoinitiator: 1~3 parts by weight; light irradiation time: 5~60s; UV lamp power of drawer-type UV curing machine: 2.2KW.

[0009] The KH-572 oligomer, MMA (methyl methacrylate) monomer, and photoinitiator (2-hydroxy-2-methyl-1-phenylpropane-1-one) were mixed under light-protected conditions until all components were homogeneous, resulting in a clear and transparent UV-curable mixture. Curing was then performed in a drawer-type UV curing machine with the distance between the light source and the sample adjusted to 10 cm, under ambient air conditions at room temperature.

[0010] Preferably, the amount of KH-572 oligomer added is 70% of the total weight, the amount of MMA added is 30% of the total weight, and the amount of photoinitiator added is 3% of the total weight.

[0011] Compared with the prior art, the present invention has the following beneficial effects: This application utilizes precise control of hydrolysis-condensation process parameters to prepare (meth)acryloyloxysilane oligomers with relatively high polymerization degrees. The structural diversity of these oligomers ensures performance differences between batches, laying a solid foundation for the subsequent preparation of curable coatings with optimizable performance. When these oligomers are copolymerized and cured with methyl methacrylate monomers, their excellent compatibility prevents phase separation, resulting in a uniform and dense cross-linked network structure. This significantly reduces the internal stress of the cured coating and effectively improves its adhesion and surface smoothness to various substrates. More importantly, since the degree of polymerization of the oligomer is directly related to the surface properties of the cured coating, such as hydrophobicity, by selecting oligomers with specific polymerization degrees, precise design and control of the coating's surface functions can be achieved, thereby meeting the specific needs of different application scenarios. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 To prepare KH-572 oligomers (n=10) 1 H-NMR spectrum.

[0014] Figure 2 GPC diagram of the prepared KH-572 oligomer (n=10).

[0015] Figure 3 The water contact angle between KH-572 oligomer and MMA photocurable thin coating. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should be covered within the protection scope of this invention.

[0017] The following testing standards and methods are adopted in the implementation of this application: GPC test: A PL-GPC50 gel permeation chromatograph was used. Polydimethylsiloxane (Polymer Standards, Inc.) with a known molecular weight was used as the standard sample. Toluene was used as the mobile phase, the flow rate was 1.0 mL / min, and the column temperature was 35℃. The molecular weight was calculated by converting the time of sample elution in the chromatographic column to the time of standard sample flow. Dynamic viscosity test: According to GB / T2794-2013 standard, the dynamic viscosity was measured using a Brookfield DV2TRVTJ 0 rotational viscometer at a constant temperature of 25±0.1℃ and a rotation speed of 200 rpm for 5 minutes. The uncertainty of dynamic viscosity was 1%. 1 H-NMR test: The sample was dissolved in deuterated chloroform (CDCl3) solvent without internal standard and tested using a 500 MHz Bruker nuclear magnetic resonance spectrometer (AVANCE Ⅲ). Water contact angle test: In accordance with GB / T 30693-2014 standard, the water contact angle of the smooth surface of each UV-cured sample was tested using a KRUSS DSA 30 water contact angle measuring instrument (KRUSS GmbH, Germany). The water contact angle of each sample was measured three times at different locations and the average value was taken.

[0018] Example 1 Preparation of KH-572 oligomer (n 单体 :n 水 =1:0.806) S1. At room temperature, add 90g of KH-572 monomer, 13.5g of methanol solvent, 3.6g of concentrated hydrochloric acid, 0.45g of high-efficiency polymerization inhibitor ZM-701, and 5.27g of deionized water to a three-necked flask. S2. After the materials are prepared, turn on the magnetic stirrer and the constant temperature heating device. After the temperature of the vessel reaches 45°C, add the deionized water from the constant pressure dropping funnel into the flask evenly over 0.5 hours. After the deionized water is added, control the temperature of the vessel to stabilize at 45°C and carry out the aging reaction for 2 hours. S3. Immediately control the reactor temperature to 60℃ and carry out the aging reaction again for 4 hours; S4. Distill under vacuum conditions to remove the solvent from the flask until the solvent distillation is complete.

[0019] Testing: The product was subjected to NMR analysis, which showed that the degree of polymerization of KH-572 oligomer was 5, the dynamic viscosity was 59.7 cp, the number average molecular weight was 846 g / mol, and the polydispersity index (PDI) was 1.21.

[0020] Example 2 Preparation of KH-572 oligomer (n 单体 :n 水 =1:0.921) S1. The difference between this step and Example 1 is that the amount of deionized water used is 6.42 g; S2. This step is the same as in Example 1; S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0021] Tests: The product was subjected to NMR analysis, which showed that the degree of polymerization of KH-572 oligomer was 10, the dynamic viscosity was 63.2 cp, the number average molecular weight was 1132 g / mol, and the polydispersity index (PDI) was 1.38.

[0022] Example 3 Preparation of KH-572 oligomer (n 单体 :n 水 =1:0.941) S1. The difference between this step and Example 1 is that the amount of deionized water used is 6.56 g; S2. This step is the same as in Example 1; S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0023] Testing: The product was subjected to NMR analysis, which showed that the degree of polymerization of KH-572 oligomer was 15, the dynamic viscosity was 65.5 cp, the number average molecular weight was 1897 g / mol, and the polydispersity index (PDI) was 1.33.

[0024] Example 4 Preparation of KH-572 oligomer (n 单体 :n 水 =1:0.951) S1. The difference between this step and Example 1 is that the amount of deionized water used is 6.63 g; S2. This step is the same as in Example 1; S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0025] Testing: The product was subjected to NMR analysis, which showed that the degree of polymerization of KH-572 oligomer was 20, the dynamic viscosity was 69.4 cp, the number average molecular weight was 2049 g / mol, and the polydispersity index (PDI) was 1.25.

[0026] Example 5 Preparation of KH-572 oligomer (n 单体 :n 水 =1:0.961) S1. The difference between this step and Example 1 is that the amount of deionized water used is 6.70 g; S2. This step is the same as in Example 1; S3. This step is the same as in Example 1; S4. This step is the same as in Example 1.

[0027] Tests: The product was subjected to NMR analysis, and the degree of polymerization of KH-572 oligomer was 25, the dynamic viscosity was 73.8 cp, the number average molecular weight was 2891 g / mol, and the polydispersity index (PDI) was 1.39.

[0028] Comparative Example 1: Preparation of KH-572 oligomers S1. This step is the same as in Example 1; S2. This step is the same as in Example 1; S3. The difference between this step and Example 1 is that the pot temperature is controlled at 120°C; S4. This step is the same as in Example 1, but the product gels during the process of heating and desolventizing.

[0029] Comparative Example 2: Preparation of KH-572 oligomers (n 单体 :n 水 =1:3) S1. The difference between this step and Example 1 is that the amount of deionized water used is 20.92g; S2. This step is the same as in Example 1; S3. This step is the same as in Example 1; S4. This step is the same as in Example 1, but the product gels during the process of heating and desolventizing.

[0030] The results of the preparation of KH-572 oligomers are summarized in Table 1 below: Table 1: Preparation of KH-572 oligomers a. with 1 The area integral value of the methoxy proton is calculated when the integrated area of ​​the propylene proton in the oligomer molecular structure in the H-NMR spectrum is 2.

[0031] b. Dynamic viscosity at 25±0.1℃, rotor model SC4-21.

[0032] Application Example 1: Preparation of a UV-curable coating of KH-572 oligomer and MMA S1. Mix 0.3g of MMA, 0.04g of photoinitiator, and 0.7g of KH-572 oligomer (product of Example 1) in a vortex stirrer until homogeneous, and place on a glass plate; S2. Curing is performed for 30 seconds in a drawer-type UV curing machine under ambient air temperature.

[0033] Test: The product was subjected to a water contact angle test. The average water contact angle of the smooth surface of the UV-cured sample was 69.13°.

[0034] Application Example 2: Preparation of a UV-curable coating of KH-572 oligomer and MMA S1. This step is the same as in Application Example 1, except that KH-572 oligomer is the product of Example 2; S2. This step is the same as in Example 1.

[0035] Test: The product was subjected to a water contact angle test. The average water contact angle of the smooth surface of the UV-cured sample was 82.54°.

[0036] Application Example 3: Preparation of a UV-curable coating of KH-572 oligomer and MMA S1. This step is the same as in Application Example 1, except that KH-572 oligomer is the product of Example 3; S2. This step is the same as in Example 1.

[0037] Test: The product was subjected to a water contact angle test. The average water contact angle of the smooth surface of the UV-cured sample was 93.16°.

[0038] Application Example 4: Preparation of a UV-curable coating of KH-572 oligomer and MMA S1. This step is the same as in Application Example 1, except that KH-572 oligomer is the product of Example 4; S2. This step is the same as in Example 1.

[0039] Test: The product was subjected to a water contact angle test. The average water contact angle of the smooth surface of the UV-cured sample was 100.27°.

[0040] Application Example 5: Preparation of a UV-curable coating of KH-572 oligomer and MMA S1. This step is the same as in Application Example 1, except that KH-572 oligomer is the product of Example 5; S2. This step is the same as in Example 1.

[0041] Test: The product was subjected to a water contact angle test. The average water contact angle of the smooth surface of the UV-cured sample was 114.83°.

[0042] Comparative Example 3: Preparation of a UV-cured coating without added MMA S1. This step is the same as in Application Example 1, except that 0.04g of photoinitiator and 0.7g of KH-572 are mixed evenly in a vortex stirrer and then placed on a glass plate. S2. This step is the same as in Example 1.

[0043] Test: Unable to form a coating.

[0044] Comparative Example 4: Preparation of KH-572 oligomer and MMA photocurable coating S1. This step is the same as in Application Example 1, except that KH-572 oligomer is the product of Example 2; S2. Curing at room temperature in air for 60 seconds.

[0045] Test: The sample cracked.

[0046] The key properties of each composite coating were tested, and the results are summarized in Table 2 below: Table 2: Performance of UV-cured coatings Comprehensive test data show that this application innovatively synthesizes a high-polymerization-degree KH-572 oligomer and successfully achieves UV curing of it with MMA. This not only overcomes the technical bottleneck of the direct application of this compound in UV curing systems but also significantly improves the overall performance of the cured product. Compared with low-polymerization-degree mixtures in existing technologies, the high-polymerization-degree oligomer prepared in this application forms a more complete three-dimensional cross-linked network during the curing process. This allows the cured coating to maintain excellent adhesion while also significantly improving its hydrophobic properties, thus successfully expanding the application prospects of this material in the field of high-end functional coatings.

[0047] As can be seen from Comparative Example 3, the KH-572 monomer cannot be effectively cured under the same conditions, remaining in a viscous flow state and failing to form a complete solid coating. This phenomenon proves that when the KH-572 monomer directly participates in the UV curing system, its multiple highly reactive alkoxy groups and (meth)acryloyloxy groups lead to uncontrollable crosslinking kinetics, making it impossible to construct an effective three-dimensional network structure.

[0048] As can be seen from Comparative Example 4, excessively long UV irradiation causes the KH-572 oligomer to react too thoroughly with the MMA double bonds, forming a three-dimensional network with excessively high cross-linking density and an overly dense mesh structure. This highly cross-linked network not only loses the necessary chain segment mobility to relax stress but also concentrates the significant volumetric shrinkage stress generated during polymerization. Simultaneously, the high proportion of KH-572 oligomer, synergistically with the rigid MMA structure, already tends to form a hard and brittle phase; under excessive energy input, the material's toughness further decreases. When the accumulated internal stress exceeds the material's inherent tolerance limit, cracking occurs at the weakest point. This indicates that a 60-second curing time far exceeds the optimal process window for this formulation.

[0049] In stark contrast, this application successfully solved the technical challenge of the inability to apply monomers by pre-designing and synthesizing high-polymerization-degree oligomers with specific structures. Examples show that these oligomers can rapidly form a smooth, transparent, and fully cured coating under the same curing conditions, achieving a fundamental breakthrough from "inability to form a coating" to "successful curing."

[0050] More importantly, this high degree of polymerization structure brings significant performance advantages to the final product. The cured coating exhibits high hydrophobicity (water contact angle 114.83°), indicating that the longer molecular chain structure helps to form a more robust microstructure in the cured network. The higher degree of polymerization allows the oligomers to build a more complete three-dimensional network during the curing process, thereby effectively improving the overall performance of the material.

[0051] This application successfully prepared a target product with a specific high degree of polymerization by precisely controlling the synthesis process of KH-572 oligomers. Compared with the direct application of monomers, this application not only solves the fundamental coating problem, but more importantly, by optimizing the molecular structure, the final product achieves excellent surface and adhesion properties, providing a reliable technical solution for the development of high-performance UV-curable coating materials.

[0052] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a (meth)acryloyloxysilane oligomer, characterized in that, Includes the following steps: S1. Add 3-methacryloyloxypropylmethyldimethoxysilane, methanol, polymerization inhibitor ZM-701 and hydrochloric acid to the reaction vessel, mix well and heat to 40~60℃, add deionized water dropwise to the mixture at a uniform rate, and control the dropwise time to 1~3h. S2. After the addition is complete, raise the temperature to 60~80℃ and maintain it for 4~6h; then remove the methanol solvent and the methanol generated in the reaction by vacuum distillation; after the distillation is completed, cool to room temperature to obtain (meth)acryloyloxysilane oligomer (KH-572).

2. The method for preparing a (meth)acryloyloxysilane oligomer according to claim 1, characterized in that, The main reaction equations for the above preparation method are as follows: 。 3. The method for preparing a (meth)acryloyloxysilane oligomer according to claim 1, characterized in that, In step S1, the mass ratio of methanol to 3-methacryloxypropylmethyldimethoxysilane is 10~30:100; the concentration of hydrochloric acid is 12mol / L, and the mass ratio of hydrochloric acid to 3-methacryloxypropylmethyldimethoxysilane is 1~5:100; the mass ratio of polymerization inhibitor ZM-701 to 3-methacryloxypropylmethyldimethoxysilane is 0.05~1.0:100; and the molar ratio of 3-methacryloxypropylmethyldimethoxysilane to deionized water is 1:0.7~1.

2.

4. The method for preparing a (meth)acryloyloxysilane oligomer according to claim 1, characterized in that, In step S2, the vacuum degree of the reduced pressure distillation is -0.1 to -0.07 MPa.

5. A high-performance UV-curable material, characterized in that, It is made from the following components in parts by weight: 60-70 parts by weight of (meth)acryloyloxysilane oligomer prepared by the method of any one of claims 1-4; Methyl methacrylate monomer: 30-40 parts by weight; Photoinitiator: 1-3 parts by weight.

6. The method for preparing high-performance UV-cured materials according to claim 5, characterized in that, Includes the following steps: (Methacryloxysilane oligomer (KH-572), methyl methacrylate monomer (MMA) and photoinitiator (2-hydroxy-2-methyl-1-phenylpropane-1-one) were mixed under light-protected conditions until all components were homogeneous, resulting in a clear and transparent UV-curable mixture. The mixture was then cured in a UV curing machine with the distance between the light source and the sample adjusted to 10 cm and in air at room temperature.

7. The method for preparing high-performance UV-cured materials according to claim 6, characterized in that, The curing time of the UV curing machine is 5~60s; the UV lamp power of the drawer-type UV curing machine is 2.2KW.

8. The method for preparing high-performance UV-cured materials according to claim 6, characterized in that, The amount of (meth)acryloyloxysilane oligomer added is 70% of the total weight, the amount of methyl methacrylate monomer added is 30% of the total weight, and the amount of photoinitiator added is 3% of the total weight.

9. The application of the high-performance UV-cured material according to any one of claims 6-8 in precision coating materials.

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