Preparation method and application of silicon acyl-containing phosphine oxide photoinitiator
By developing a silicacyl phosphine oxide photoinitiator, the compatibility problem between commonly used photoinitiators and silicone resins is solved, and high solubility, good compatibility and improved hydrophobicity are achieved, which is suitable for a variety of industrial applications.
Patent Information
- Application Number
- CN202311481081.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-11-08
- Publication Date
- 2025-05-09
AI Technical Summary
Commonly used long waves cause compatibility problems between commercial small molecule photoinitiators and silicone resins, resulting in low transparency and poor mechanical properties of cured materials.
A silicacyl phosphine oxide-containing photoinitiator is developed to improve its chemical structure, improve its solubility and compatibility in silicone resins, and improve its photoinitiation efficiency and migration stability through specific preparation methods.
High solubility and good compatibility in silicone resins are achieved, photo-initiation efficiency and migration stability are improved, and the resulting cured film has improved hydrophobicity and is suitable for food packaging and hydrophobic coatings and other fields.
Smart Images
Figure CN119954859A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of photoinitiators, and specifically relates to a preparation method and application of a silicon acylphosphine oxide-containing photoinitiator. Background Art
[0002] Photoinitiators based on monoacylphosphine oxide (MAPO) and bisacylphosphine oxide (BAPO) are widely used in photopolymerization because they can generate free radicals under light irradiation. Among them, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) and (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) have become the most commonly used photoinitiators.
[0003] Silicone resins containing vinyl or acrylate are important raw materials for photopolymerization. Due to their flexibility, pliability and high light transmittance, they are widely used in various fields such as LED encapsulants, transparent elastomers, 3D printing, etc. However, there are compatibility issues between commonly used long-wave-initiated commercial small-molecule photoinitiators (such as TPO and BAPO) and silicone resins. Silicone macromolecular photoinitiators themselves often have intermolecular chain entanglements, resulting in macroscopic phase separation when mixed with silicone resins. This poor compatibility results in lower transparency and poor mechanical properties of the cured material. Summary of the invention
[0004] In view of the deficiencies of the prior art, the purpose of the present invention is to improve the solubility of acylphosphine oxide in silicone resin, provide a type of silicon-containing acylphosphine oxide photoinitiator with high photoinitiation efficiency, high migration stability and high thermal stability and a preparation method thereof, which is applied to UV-LED light-cured coatings, and has high silicone resin compatibility, good photoinitiation efficiency and high migration stability, and the obtained cured film has improved hydrophobicity. It has broad application prospects in the fields of food packaging, hydrophobic coatings, etc.
[0005] Compared with the present invention, the present invention has the following advantages and effects:
[0006] The photoinitiator system of the present invention can be used to initiate visible light curing of free radical curing. The photoinitiator system of the present invention can effectively initiate rapid photocuring of free radical monomers / oligomers by irradiation with a 405nm light source.
[0007] Compared with the generally reported visible light initiation system, the photoinitiator system of the present invention has higher compatibility with silicone resin, good photoinitiator efficiency and higher migration stability. The obtained cured film has improved hydrophobicity and has potential for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 : H NMR spectrum of the silicon-containing phosphine oxide photoinitiator prepared in Example 2.
[0009] Figure 2 : NMR carbon spectrum of the silicon-containing phosphine oxide photoinitiator prepared in Example 2.
[0010] Figure 3 : H NMR spectrum of the silicon-containing phosphine oxide photoinitiator prepared in Example 4.
[0011] Figure 4 : NMR carbon spectrum of the silicon-containing phosphine oxide photoinitiator prepared in Example 4.
[0012] Figure 5 : UV-visible spectra of the silicon-containing phosphine oxide photoinitiator, TPO and TPO-L prepared in Example 2 and Example 4.
[0013] Figure 6 : C=C conversion rate curve of the silicon-containing phosphine oxide photoinitiator and TPO prepared in Example 2 under LED@405nm.
[0014] Figure 7 : C=C conversion rate curve of the silicon-containing phosphine oxide photoinitiator and TPO-L prepared in Example 4 under LED@405nm.
[0015] Figure 8 : Thermogravimetric curves of the silicon-containing acylphosphine oxide photoinitiator, TPO and TPO-L prepared in Example 2 and Example 4.
[0016] Fig. 9 : Schematic diagram of the hydrophobic angle of the cured films obtained by initiating MTQ-570 polysiloxane resin with silicon-containing phosphine oxide photoinitiator, TPO and TPO-L prepared in Example 2 and Example 4.
[0017] Fig.10 : Schematic diagram of the silicon-containing acylphosphine oxide photoinitiator prepared in Examples 1-6, wherein R1=H or CH2-S-CH2CH2CH2-Si(OCH2CH3)3, R2=H or CH2-S-CH2-S-CH2CH2CH2-Si(OCH2CH3)3. DETAILED DESCRIPTION
[0018] The technical solution of the present invention is further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification or change made to the present invention will fall within the protection scope of the present invention.
[0019] In the present invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used can be purchased from the market or are commonly used in the art.
[0020] The test method in the embodiment is described as follows:
[0021] (1) Solubility test
[0022] At room temperature, the photoinitiator (the photoinitiator prepared in Example 2 and Example 4, TPO and TPO-L) was mixed with three monomers, trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA), and polysiloxane acrylate (MTQ-570), respectively, and the photoinitiator was continuously added until the photoinitiator was just completely dissolved. Test the solubility of the initiator in the monomer. Record the mass of the photoinitiator as mlight, the mass of the monomer as mmono, and the solubility S of the photoinitiator in the monomer according to formula 1-1:
[0023]
[0024] (2) Migration test
[0025] Two different curing recipes were formed by adding 1% of photoinitiator (prepared by Example 2 and Example 4, respectively) using TMPTA as the curing monomer. The curing mixture was then evenly distributed on a glass slide coated with a 1 mm thick silicone spacer. Subsequently, the above samples were placed under a wavelength of 405 nm and an intensity of 100 mW / cm 2 The film was then cut into small pieces and then crushed into powder. Subsequently, 100 mg of the powdered substance was dissolved in 2 mL of anhydrous ethanol and then soaked at 25 ° C for 48 hours. After the filtration process, the powder was diluted to a volume of 10 mL. Subsequently, the absorbance of Example 2 and Example 4 was measured at the maximum absorption wavelength using a UV-5320 (UNICO) spectrophotometer. The mobility was determined according to formula 1-2:
[0026]
[0027] Wherein, A is the absorbance of the photoinitiator at the maximum absorption wavelength, Mr is the molecular weight of the photoinitiator, V is the volume of the filtrate (10 mL), ε is the molar extinction coefficient of the photoinitiator, l is the light propagation length (1 cm), m0 is the mass of the powder, and b is the mass fraction of the photoinitiator (1 wt%).
[0028] (3) Double bond conversion rate test
[0029] MTQ-570 was used as a curing monomer, and 1-3 wt% of a photoinitiator (the photoinitiator prepared in Example 2 and Example 4) was added and stirred evenly. A 0.6 mm thick silicone gasket was fixed on a glass slide, and a circular hole with a diameter of 1 cm was formed on the gasket. After the photocurable formulation was evenly covered on the circular hole, a second glass slide was added on top of it to isolate it from the surrounding air. A light source with a wavelength of 405 nm was used to irradiate the glass slide, and a Nicolet 5700 was used to irradiate the glass slide.
[0030] Double bond conversion rate (%) = (1-S t / S0)×100% Formula 1-3 The leaf transform spectrometer records the infrared spectra at different time periods. According to formula 1-3, the double bond conversion rate at different illumination times is calculated. The results are shown in Figure 6 and Figure 7 shown.
[0031] Where S t Represents the double bond characteristic absorption peak 6165cm when the illumination time is t -1 S0 is the peak area of the characteristic peak before illumination.
[0032] (4) Thermal stability test
[0033] The thermal properties of the photoinitiator were tested using a DTG-60AH DTG-TGA simultaneous analyzer in a nitrogen environment with a nitrogen flow rate of 50 ml / min. The temperature was increased from 30°C to 800°C at a heating rate of 10°C / min.
[0034] (5) Hydrophobicity test
[0035] The contact angle of ultrapure water on the cured film was measured by sessile drop method at an ambient temperature of 20℃.
[0036] Example 1
[0037] Synthesis of Photoinitiator TPO-Si-S
[0038] The synthesis process is shown in the following formula:
[0039]
[0040] TPO-Cl-S and KH-580 were mixed and dissolved in THF in a molar ratio of 1:1.2. Anhydrous potassium carbonate equal to the mass of the initiator was added, and the mixture was heated to reflux. Thin layer chromatography (TLC) was used to monitor the progress of the reaction. After the reaction was completed, solid potassium carbonate was filtered out. The solvent in the filtrate was removed by rotary distillation. The resulting liquid was dissolved in dichloromethane and washed three times with water. After drying, the solvent was removed by rotary distillation to obtain the product TPO-Si-S (colorless / yellow transparent liquid) with a yield of 90%.
[0041] Example 2
[0042] Synthesis of Photoinitiator TPO-Si-D
[0043] The synthesis process is shown in the following formula:
[0044]
[0045] TPO-Cl-D and KH-580 were mixed and dissolved in THF in a molar ratio of 1:2.4. Anhydrous potassium carbonate equal to the mass of the initiator was added, and the mixture was heated to reflux. Thin layer chromatography (TLC) was used to monitor the progress of the reaction. After the reaction was completed, solid potassium carbonate was filtered out. The solvent in the filtrate was removed by rotary distillation. The resulting liquid was dissolved in dichloromethane and washed three times with water. After drying, the solvent was removed by rotary distillation to obtain the product TPO-Si-D (colorless / yellow transparent liquid) with a yield of 89%.
[0046] Example 3
[0047] Synthesis of Photoinitiator TPO-L-Si-S
[0048] The synthesis process is shown in the following formula:
[0049]
[0050] TPO-L-Cl-S and KH-580 were mixed and dissolved in THF in a molar ratio of 1:1.2. Anhydrous potassium carbonate equal to the mass of the initiator was added, and the mixture was heated to reflux. Thin layer chromatography (TLC) was used to monitor the progress of the reaction. After the reaction was completed, solid potassium carbonate was filtered out. The solvent in the filtrate was removed by rotary distillation. The resulting liquid was dissolved in dichloromethane and washed three times with water. After drying, the solvent was removed by rotary distillation to obtain the product TPO-L-Si-S (colorless / yellow transparent liquid) with a yield of 87%.
[0051] Example 4
[0052] Synthesis of Photoinitiator TPO-Si-LD
[0053] The synthesis process is shown in the following formula:
[0054]
[0055] TPO-L-Cl-D and KH-580 were mixed and dissolved in THF in a molar ratio of 1:2.4. Anhydrous potassium carbonate equal to the mass of the initiator was added, and the mixture was heated to reflux. Thin layer chromatography (TLC) was used to monitor the progress of the reaction. After the reaction was completed, solid potassium carbonate was filtered out. The solvent in the filtrate was removed by rotary distillation. The resulting liquid was dissolved in dichloromethane and washed three times with water. After drying, the solvent was removed by rotary distillation to obtain the product TPO-L-Si-D (colorless / yellow transparent liquid) with a yield of 88%.
[0056] Example 5
[0057] Synthesis of Mixed Photoinitiator TPO-Si-S / D
[0058] The synthesis process is shown in the following formula:
[0059]
[0060] The synthesis process is as described in Example 1-2, KH-580 is added in excess, and the product is a mixture of TPO-Si-S and TPO-Si-D.
[0061] Example 6
[0062] Synthesis of Mixed Photoinitiator TPO-L-Si-S / D
[0063] The synthesis process is shown in the following formula:
[0064]
[0065] The synthesis process is as described in Example 2-4, KH-580 is added in excess, and the product is a mixture of TPO-L-Si-S and TPO-L-Si-D.
[0066] Performance Testing
[0067] 1. Solubility test
[0068] Table 1 Solubility of photoinitiators in different monomers
[0069]
[0070] It can be seen from Table 1 that the solubility of the photoinitiator of the embodiment in the three monomers is greater than 50%, that is, it has good solubility. High solubility can reduce the loss caused by dissolving the initiator and improve production efficiency.
[0071] 2. Migration test
[0072]
[0073]
[0074] It can be seen from Table 2 that the mobility of the photoinitiator in the embodiment of the present invention is so low that it is unmeasurable. Therefore, the initiator in the above embodiment has a better migration stability than TPO and TPO-L.
[0075] 3. Double bond conversion rate and UV absorption
[0076] Depend on Figure 6 and Figure 7 It can be seen that under the irradiation of 405nm light source, the photoinitiation efficiency of 1wt% Example 2 and Example 4 is slightly lower than that of TPO and TPO-L. When the content of Example 2 and Example 4 is increased to 2-3wt%, the photoinitiation efficiency comparable to that of TPO and TPO-L can be obtained.
[0077] The UV absorption spectra of the photoinitiators, TPO and TPO-L prepared in Example 2 and Example 4 are as follows: Figure 5 As shown, from Figure 5 It can be seen that the molar extinction coefficients of the photoinitiators prepared in Examples 2 and 4 are reduced.
[0078] 4. Thermal stability test
[0079] The thermal properties of the photoinitiator were tested using a DTG-60AH DTG-TGA simultaneous analyzer in a nitrogen environment with a nitrogen flow rate of 50 ml / min. The temperature was increased from 30°C to 800°C at a heating rate of 10°C / min.
[0080] like Figure 8 As shown, the photoinitiators prepared in Example 2 and Example 4 have higher thermal stability.
[0081] 5. Hydrophobicity test
[0082] The contact angle of ultrapure water on the cured film was measured by sessile drop method at an ambient temperature of 20℃.
[0083] like Fig. 9 As shown, the cured films obtained by polymerization of MTQ-570 initiated by the photoinitiators prepared in Examples 2 and 4 have better hydrophobicity.
Claims
1. A type of silicon-containing phosphine oxide photoinitiator, characterized in that: The structural formula is as follows. Where R1=H,CH2-S-CH2CH2CH2-Si(OCH3)3,CH2-S-CH2CH2CH2- Si(OCH2CH3)3,CH2-S-CH2CH2CH2-SiCH3(OCH2CH3)2,CH2-S- CH2CH2CH2-SiCH3(OCH3)2,R2=H,CH2-S-CH2CH2CH2-Si(OCH3)3,CH2-S-CH2CH2CH2-Si(OCH2CH3)3,CH2-S-CH2CH2CH2-SiCH3(OCH3)2.
2. The silicon-containing acylphosphine oxide photoinitiator according to claim 1, characterized in that: TPO-Cl-S, TPO-Cl-D, TPO-L-Cl-S or TPO-L-Cl-D is mixed with a mercapto-containing silane coupling agent and a base catalyst and dissolved in solvent 1. The reaction is monitored by TLC until it is complete. After washing with water and drying, the solvent is removed to obtain a silicon-containing acylphosphine oxide photoinitiator.
3. The preparation method according to claim 2, characterized in that: The solvent 1 is one of ethanol, acetonitrile, DMF, DMSO, and THF; The base catalyst is one or more of triethylamine, sodium carbonate, potassium carbonate, and sodium bicarbonate; The mercapto-containing silane coupling agent is a series of mercapto-containing organic silicon monomers such as γ-mercaptopropyltriethoxysilane (KH-580) and γ-mercaptopropyltrimethoxysilane (KH-590); The mass ratio of the TPO-Cl-S, TPO-Cl-D, TPO-L-Cl-S or TPO-L-Cl-D to the base catalyst is 1:1; The mass ratio of the TPO-Cl-S, TPO-Cl-D, TPO-L-Cl-S or TPO-L-Cl-D to the solvent is 1:10; The molar ratio of the TPO-Cl-S, TPO-Cl-D, TPO-L-Cl-S or TPO-L-Cl-D to the silane coupling agent is 1:2-10; The reaction temperature is 40°C to 65°C; the reaction time is 5-48 hours; The purification is to remove the alkali catalyst by washing with water and remove the solvent under reduced pressure.