Acylphosphine oxide photoinitiator and its preparation method and use

Abstract

The present invention relates to an acylphosphine oxide photoinitiator, a preparation method and use thereof. The acylphosphine oxide photoinitiator comprises two or three symmetrically distributed acylphosphine oxide groups, which are connected by specific groups. The obtained photoinitiator exhibits high photoinitiating activity and has the characteristics of low mobility, low odor and low toxicity compared to the photoinitiator TPO. Compared with TPO, the photoinitiator has broader application prospects. In addition, the preparation method has a short process flow, simple operation, and is convenient for industrial application.

Description

Technical Field

[0001] The invention belongs to the field of photocurable materials and relates to an acylphosphine oxide photoinitiator and a preparation method and application thereof. Background Art

[0002] Acylphosphine oxide photoinitiators are a type of photoinitiator with high photoinitiating activity and excellent overall performance. They are classified as cleavage-type free radical photoinitiators. Currently, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO) is a commercially available and widely used product. TPO has sufficient solubility in reactive diluents and an absorption wavelength of up to 430 nm. Upon photolysis, it produces two highly active free radicals: the mesitylene trimethylbenzoyl radical and the diphenylphosphine radical. However, as a small molecule photoinitiator, TPO carries the risks of migration and toxicity.

[0003] The prior art uses photoinitiators TPO and TPO-L as raw materials, and introduces polymerizable double bond functional groups through reactions to obtain TPO-X and TPO-SJ, respectively. The molecular formulas are shown below. The polymerizable double bonds participate in the polymerization reaction, thereby improving the mobility of the photoinitiator in the polymer and reducing the odor and toxicity caused by the migration of low-molecular-weight photoinitiators. However, the implementation of the above scheme requires the preparation of TPO or TPO-L first, which is a complex process. In addition, TPO or TPO-L is easily deteriorated under strong acid or strong base reaction conditions, affecting the product yield and purity.

[0004]

[0005] Therefore, it is still of great significance to develop an acylphosphine oxide photoinitiator with high photoinitiator activity, low mobility, low odor, and low toxicity and a preparation method thereof. Summary of the Invention

[0006] The present invention aims to provide an acylphosphine oxide photoinitiator, a preparation method thereof, and uses thereof. The acylphosphine oxide photoinitiator comprises two or three symmetrically distributed acylphosphine oxide groups, which are connected by specific groups. The resulting photoinitiator exhibits high photoinitiating activity and has the characteristics of low mobility, low odor, and low toxicity compared to the photoinitiator TPO. Compared with TPO, the photoinitiator has broader application prospects. The preparation method thereof has a short process flow, simple operation, and is convenient for industrial application.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides an acylphosphine oxide photoinitiator, the molecular formula of the acylphosphine oxide photoinitiator is as follows:

[0009]

[0010] Wherein, X is selected from O, S, -NR, -(CH2) m - or any one of the groups represented by the following formula (b); R is selected from a C1-C12 straight chain or branched alkyl group, a group represented by the following formula (c) or a group represented by the following formula (d);

[0011]

[0012] m is selected from 1-4, n is selected from 1-4, and R1 is selected from a C1-C12 straight chain or branched alkyl group.

[0013] The acylphosphine oxide photoinitiator of the present invention contains two or three symmetrically distributed acylphosphine oxide groups, which are connected by a specific X group. As a result, the acylphosphine oxide photoinitiator has the characteristics of low mobility, low odor, low toxicity and high initiation activity.

[0014] The acylphosphine oxide photoinitiator of the present invention has high photoinitiating activity, and compared with the photoinitiator TPO, it has low molecular mobility, lower odor and lower toxicity.

[0015] Preferably, X is selected from O, -NR, -(CH2) m - or any one of the groups represented by formula (b).

[0016] Preferably, m is 1 or 2.

[0017] Preferably, n is 1 or 2.

[0018] In the acylphosphine oxide photoinitiator of the present invention, the selection of X has a certain influence on the activity of the photoinitiator. The present invention has found through research that when X is selected from O, -NR or a group represented by formula (b), the resulting photoinitiator has higher photoinitiating activity.

[0019] Preferably, R is selected from any one of a C1-C4 linear or branched alkyl group, a group represented by formula (c) or a group represented by formula (d).

[0020] Preferably, R1 is selected from a C1-C4 linear or branched alkyl group.

[0021] Preferably, the acylphosphine oxide photoinitiator comprises any one of the following structures;

[0022]

[0023]

[0024] In a second aspect, the present invention provides a method for preparing the acylphosphine oxide photoinitiator as described in the first aspect, the preparation method comprising the following steps:

[0025] (1) mixing phenylphosphine dichloride, a compound represented by formula (e), and a catalyst, and heating the mixture to react to obtain a mixture containing an intermediate product;

[0026]

[0027] Wherein, Y is selected from O, S, -NR', -(CH2) m - or any one of the groups represented by formula (b); R' is selected from any one of a C1-C12 straight chain or branched alkyl group, a group represented by formula (c) or a phenyl group;

[0028] (2) hydrolyzing the mixture obtained in step (1), separating the liquids, and obtaining an organic phase;

[0029] (3) adding aldehyde to the organic phase in step (2) to carry out the reaction;

[0030] (4) The reaction product in step (3) is subjected to an oxidation reaction to obtain the acylphosphine oxide photoinitiator.

[0031] In the preparation method of the acylphosphine oxide photoinitiator of the present invention, when Y is selected from O, S, -NR', -(CH2) m - or any one of the groups represented by formula (b), R' is selected from a C1-C12 straight-chain or branched alkyl group or any one of the groups represented by formula (c); the reaction equation is shown below; the preparation method uses phenylphosphine dichloride and the compound represented by formula (e) as raw materials, and obtains a photoinitiator containing two symmetrical acylphosphine oxide groups in the molecule through a four-step reaction;

[0032]

[0033] It can be seen from the above reaction equations that the four-step reactions are as follows:

[0034] In the first step, phenylphosphine dichloride and the compound represented by formula (e) react in the presence of a catalyst to obtain the compound represented by formula (f);

[0035] In the second step, the compound represented by formula (f) is hydrolyzed to obtain the compound represented by formula (g);

[0036] In the third step, the compound represented by formula (g) is mixed with rice aldehyde for addition reaction to obtain the compound represented by formula (h);

[0037] In the fourth step, under the action of a catalyst, the compound represented by formula (h) is mixed with an oxidant to undergo an oxidation reaction to obtain the compound represented by formula (i), which is the acylphosphine oxide photoinitiator of the present invention.

[0038] In the present invention, in the method for preparing an acylphosphine oxide photoinitiator, when Y is selected from -NR' and R' is selected from phenyl, that is, the compound represented by formula (e) is triphenylamine; a photoinitiator containing three acylphosphine oxide symmetrical groups in the molecule can be prepared; the reaction equation is shown below:

[0039] The reaction equation comprises four steps, which are shown below:

[0040] In the first step, phenylphosphine dichloride and triphenylamine react in the presence of a catalyst to obtain a compound represented by formula (j);

[0041] In the second step, the compound represented by formula (j) is hydrolyzed to obtain the compound represented by formula (k);

[0042] In the third step, the compound represented by formula (k) is mixed with rice aldehyde for addition reaction to obtain the compound represented by formula (l);

[0043] In the fourth step, under the action of a catalyst, the compound represented by formula (1) is mixed with an oxidant to undergo an oxidation reaction to obtain a compound represented by formula (m), namely, the acylphosphine oxide photoinitiator of the present invention.

[0044]

[0045] The present invention adopts the above method to prepare the photoinitiator containing two or three acylphosphine oxide symmetrical groups in the molecule of the present invention, and the process route is short and the cost is low.

[0046] Preferably, the catalyst in step (1) comprises aluminum trichloride.

[0047] Preferably, the temperature of the heating reaction in step (1) is 100°C to 150°C, such as 110°C, 120°C, 130°C or 140°C, etc., preferably 110°C to 130°C.

[0048] Here, phenylphosphine dichloride and the compound represented by formula (e) are reacted under heating conditions, and the reaction temperature is limited to the above range, which is conducive to the progress of the reaction and can well avoid the occurrence of side reactions. When the reaction temperature is too low, the reaction rate is slow and the reaction is incomplete; when the reaction temperature is too high, the selectivity of the reaction is reduced and the side reactions increase. The increased side reactions are as follows: thereby reducing the reaction yield;

[0049]

[0050] Preferably, in step (1), the molar ratio of phenylphosphine dichloride, the compound represented by formula (e), and the catalyst is 2-3:1:2-4, for example, 2:1:2.4 or 3:1:3.2.

[0051] Preferably, before the hydrolysis in step (2), the mixture in step (1) is mixed with a non-polar solvent for dilution.

[0052] Preferably, the dilution further includes cooling.

[0053] Preferably, the non-polar solvent includes at least one of toluene, xylene, ethylbenzene and chlorobenzene.

[0054] In the present invention, after the first step reaction is completed and before the hydrolysis reaction, a non-polar solvent is used to dilute the mixture obtained in the first step reaction, which facilitates the subsequent hydrolysis and liquid separation processes.

[0055] Preferably, the hydrolysis method comprises adding dropwise the mixed solution obtained by diluting the mixture in step (1) into water.

[0056] Preferably, the temperature during the hydrolysis process is ≤20°C, such as 10°C, 12°C, 15°C or 18°C.

[0057] Preferably, the hydrolysis process is accompanied by stirring.

[0058] In the present invention, the hydrolysis reaction adopts the above-mentioned mixing method and temperature conditions, which is beneficial to reducing the color of the reaction system, making it easier to separate the layers, and facilitating post-processing. When the temperature is too high, the reaction itself releases heat significantly, which is not conducive to temperature control. At the same time, if the temperature is too high, the reaction system will produce impurities, making it difficult for the aqueous phase and the organic phase to separate, or even inseparable. The reaction system is a viscous liquid, which is not conducive to the continued reaction.

[0059] Preferably, the ratio of the molar amount of methyl aldehyde added in step (3) to the molar amount of phenylphosphine dichloride in step (1) is 0.8 to 1.5:1, for example, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1 or 1.4:1, etc.

[0060] Preferably, the reaction temperature in step (3) is 15°C to 40°C, such as 20°C, 25°C, 30°C or 35°C, and preferably 20°C to 35°C.

[0061] Preferably, the reaction time in step (3) is 2 h to 12 h, for example, 3 h, 5 h, 7 h, 9 h or 11 h.

[0062] Preferably, after the reaction in step (3) is completed, the temperature is further lowered to 10°C to 15°C, such as 11°C, 12°C, 13°C or 14°C.

[0063] In the present invention, before the oxidation reaction begins, the temperature of the reaction liquid is controlled within the above range, and then the catalyst and oxidant are added to carry out the oxidation reaction. Since the oxidation reaction step is significantly exothermic, the reaction temperature must be controlled to avoid decomposition of the high-temperature substrate, reduce the occurrence of side reactions, and effectively control the reaction to proceed smoothly and safely.

[0064] Preferably, the method for the oxidation reaction in step (4) comprises adding a catalyst and an oxidant to the reaction product in step (3), mixing, and conducting an oxidation reaction.

[0065] Preferably, the catalyst in the oxidation reaction is selected from at least one of a vanadium-containing catalyst, a heteropolyacid catalyst and a heteropolyacid salt catalyst, wherein the vanadium-containing catalyst is such as vanadium acetylacetonate; a heteropolyacid catalyst or a heteropolyacid salt catalyst is such as tungstic anhydride, tungstate, molybdic anhydride, molybdate, phosphomolybdate or a mixture thereof.

[0066] Preferably, the amount of catalyst used in the oxidation reaction is selected from 0.1%-10% by mass of phenylphosphine dichloride, such as 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8% or 9%.

[0067] Preferably, the oxidant is selected from peroxides, and the peroxide is preferably hydrogen peroxide and / or tert-butyl peroxide;

[0068] Preferably, the amount of the oxidant in the oxidation reaction is 1-3 times the amount of the phenylphosphine dichloride substance; for example, 1.5 times, 2 times or 2.5 times, etc.

[0069] Preferably, the oxidant is added dropwise.

[0070] Preferably, the oxidation reaction in step (4) further includes alkali washing, liquid separation, water washing, and desolventizing.

[0071] Preferably, the alkali solution used in the alkali washing includes at least one of a sodium hydroxide aqueous solution, a sodium carbonate aqueous solution or a sodium bicarbonate aqueous solution, preferably a sodium hydroxide aqueous solution.

[0072] The purpose of the alkaline washing in the present invention is to remove organic acidic impurities, improve the stratification effect of the aqueous phase and the organic phase, and avoid long-term standing; it is also to adjust the reaction solution to alkaline to avoid corrosion of subsequent reaction equipment by the acidic system.

[0073] Preferably, the temperature of the alkali washing is ≤20°C, for example, 10°C, 12°C, 14°C, 15°C, 16°C, 18°C ​​or 19°C.

[0074] Preferably, the alkali solution used for the alkali washing is selected from a sodium hydroxide aqueous solution with a concentration of 15wt% to 25wt%, such as 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, 21wt%, 22wt%, 23wt% or 24wt%, etc.

[0075] In the present invention, the alkali washing temperature is controlled within the above range. In an alkaline system, if the temperature is too high or the alkaline concentration is too high, the decomposition of the reaction products will be accelerated.

[0076] Preferably, the alkali washing process is accompanied by stirring.

[0077] Preferably, the organic phase obtained from the end point of the water washing to the separation is neutral.

[0078] As a preferred technical solution of the present invention, the preparation method of the acylphosphine oxide photoinitiator comprises the following steps:

[0079] (I) mixing phenylphosphine dichloride, a compound represented by formula (e), and aluminum chloride in a reaction vessel, heating to 100-150° C. for reaction, and cooling to obtain a mixture containing an intermediate product;

[0080]

[0081] Wherein, Y is selected from O, S, -NR', -(CH2) m - or any one of the groups represented by formula (b); R' is selected from any one of a C1-C12 straight chain or branched alkyl group, a group represented by formula (c) or a phenyl group;

[0082] (II) adding a non-polar solvent to the mixture in step (I) to dilute it to obtain a mixed solution, then adding the mixed solution dropwise to water at a temperature of ≤20°C with stirring to hydrolyze it, and separating the liquids to obtain an organic phase;

[0083] (III) adding rice aldehyde to the organic phase in step (II), reacting at 15°C to 40°C for 2h to 12h, and then cooling to 10-15°C;

[0084] (IV) adding a catalyst to the reaction product in step (III), and then dropwise adding a peroxide to carry out an oxidation reaction;

[0085] (V) adding a 15 wt % to 25 wt % aqueous sodium hydroxide solution to the reaction product in step (IV) at a temperature of ≤ 20° C. with stirring, separating the layers, washing the organic phase with water until neutral, and desolventizing to obtain the acylphosphine oxide photoinitiator.

[0086] In a third aspect, the present invention provides use of the acylphosphine oxide photoinitiator as described in the first aspect, wherein the acylphosphine oxide photoinitiator is used in a photocuring system with a wavelength of 300 nm to 450 nm.

[0087] Preferably, the acylphosphine oxide photoinitiator is used in the fields of inks, coatings, tooth restoration, 3D printing, and pipeline repair.

[0088] Compared with the prior art, the present invention has the following beneficial effects:

[0089] (1) Compared with the photoinitiator TPO, the acylphosphine oxide photoinitiator of the present invention has the characteristics of low mobility, low odor and low toxicity;

[0090] (2) The acylphosphine oxide photoinitiator of the present invention contains two or three acylphosphine oxide groups that are symmetrically distributed, and the above groups are connected using specific groups defined in the present invention, so that the resulting photoinitiator maintains high photoinitiating activity and photocuring efficiency. DETAILED DESCRIPTION

[0091] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0092] Example 1

[0093] The molecular formula of the acylphosphine oxide photoinitiator described in this embodiment is as follows:

[0094]

[0095] The preparation method of the acylphosphine oxide photoinitiator in this embodiment comprises the following steps:

[0096] (I) In a four-necked flask, 29.2 g (0.22 mol) of aluminum trichloride, 36 g (0.2 mol) of phenylphosphine dichloride, and 17 g (0.1 mol) of diphenyl ether were added in sequence, mixed, and heated to 120° C. for reaction until the reaction of phenylphosphine dichloride was complete as determined by GC, and then cooled to obtain a mixture containing an intermediate product;

[0097] (II) diluting the mixture in step (I) by adding toluene to obtain a mixed solution, then adding the mixed solution dropwise to 90 g of water at 15° C. with stirring for hydrolysis for 30 min, separating the liquids to obtain an organic phase;

[0098] (III) Add 29.7 g (0.2 mol) of rice aldehyde to the organic phase in step (II), react at room temperature (25°C) for 4 hours, and then cool to 15°C;

[0099] (IV) adding 0.5 g of vanadyl acetylacetonate to the reaction product in step (III), and slowly adding 28 g of 30% hydrogen peroxide dropwise to carry out an oxidation reaction, and detecting by HPLC until the intermediate reaction is complete;

[0100] (V) adding 50 g of a 20 wt % aqueous sodium hydroxide solution to the reaction product in step (IV) at 15° C. with stirring, stirring for 30 min, separating the liquids, washing the organic phase with water until neutral, and desolventizing to obtain a brown viscous liquid, i.e., an acylphosphine oxide photoinitiator; and purifying the acylphosphine oxide photoinitiator by recrystallization with a yield of 78% and a purity of 98.5%.

[0101] MS:m / z[M+1] + =711.24 (Mw=710.73).

[0102] The H-NMR analysis results of the photoinitiator in this embodiment are as follows:

[0103] 1 H-NMR (400MHz, CDCl3): δ7.30~7.1(m,14H), 6.90-6.70(m,8H), 2.40(s,12H), 2.35(s,6H).

[0104] Example 2

[0105] The molecular formula of the acylphosphine oxide photoinitiator described in this embodiment is as follows:

[0106]

[0107] The preparation method of the acylphosphine oxide photoinitiator in this example differs from that in Example 1 only in that an equal molar amount of diphenyl ether is replaced with diphenyl sulfide. Other parameters and conditions are identical to those in Example 1. The acylphosphine oxide photoinitiator is purified by recrystallization with a yield of 70% and a purity of 98.3%.

[0108] MS:m / z[M+1] + =727.21 (Mw=726.80).

[0109] The H-NMR analysis results of the photoinitiator in this embodiment are as follows:

[0110] 1 H-NMR (400MHz, CDCl3): δ7.40~7.15(m,14H), 7.10~7.00(m,4H), 6.86(s,4H), 2.30(s,18H).

[0111] Example 3

[0112] The molecular formula of the acylphosphine oxide photoinitiator described in this embodiment is as follows:

[0113]

[0114] The preparation method of the acylphosphine oxide photoinitiator in this embodiment differs from that in Example 1 only in that an equal molar amount of diphenyl ether is replaced by N-methyldiphenylamine, and other parameters and conditions are exactly the same as those in Example 1.

[0115] MS:m / z[M+1] + =724.27 (Mw=723.77).

[0116] The H-NMR analysis results of the photoinitiator in this embodiment are as follows:

[0117] 1 H-NMR (400MHz, CDCl3): δ7.42~7.32(m,10H),7.20~7.12(m,4H),6.90-6.85(m,4H),6.50-6.38(m,4H),2.82(s,3H),2.40(s,12H),2.32(s,6H).

[0118] Example 4

[0119] The molecular formula of the acylphosphine oxide photoinitiator described in this embodiment is as follows:

[0120]

[0121] The preparation method of the acylphosphine oxide photoinitiator in this embodiment differs from that in Example 1 only in that an equal molar amount of diphenyl ether is replaced by 4-methyltriphenylamine, and other parameters and conditions are exactly the same as those in Example 1.

[0122] MS:m / z[M+1] + =800.30 (Mw=799.87).

[0123] The H-NMR analysis results of the photoinitiator in this embodiment are as follows:

[0124] 1 H-NMR (400MHz, CDCl3): δ7.50~7.41(m,10H),7.23~7.15(m,4H),7.08~6.90(m,6H) ),6.75-6.49(m,4H),6.39~6.30(m,2H),2.35(s,12H),2.28(s,6H),2.22(s,3H).

[0125] Example 5

[0126] The molecular formula of the acylphosphine oxide photoinitiator described in this embodiment is as follows:

[0127]

[0128] The preparation method of the acylphosphine oxide photoinitiator in this embodiment comprises the following steps:

[0129] (I) In a four-necked flask, 43.8 g (0.33 mol) of aluminum chloride, 54 g (0.3 mol) of phenylphosphine dichloride, and 24.6 g (0.1 mol) of triphenylamine were added in sequence, mixed, and heated to 130° C. for reaction until the reaction of phenylphosphine dichloride was complete as determined by GC, and then cooled to obtain a mixture containing an intermediate product;

[0130] (II) diluting the mixture in step (I) by adding toluene to obtain a mixed solution, then adding the mixed solution dropwise to 150 g of water at 10° C. with stirring for hydrolysis for 45 min, separating the liquids to obtain an organic phase;

[0131] (III) adding 44.4 g (0.3 mol) of rice aldehyde to the organic phase in step (II), reacting at 25°C for 4 h, and then cooling to 15°C;

[0132] (IV) adding 0.75 g of vanadyl acetylacetonate to the reaction product in step (III), and slowly adding 42 g of 30% hydrogen peroxide dropwise to carry out an oxidation reaction, and detecting by HPLC until the intermediate reaction is complete;

[0133] (V) adding 75 g of a 20 wt % aqueous sodium hydroxide solution to the reaction product of step (IV) at 15° C. with stirring, stirring for 30 min, separating the layers, washing the organic phase with water until neutral, and desolvating to obtain the acylphosphine oxide photoinitiator;

[0134] Detected by HPLC, trifunctional group: bifunctional group = 8:2, MS: m / z [M+1] + =1056.36 (Mw=1056.11) (trifunctional group), [M+1] + =786.28 (Mw=785.84) (bifunctional).

[0135] Example 6

[0136] The molecular formula of the acylphosphine oxide photoinitiator described in this embodiment is as follows:

[0137]

[0138] The preparation method of the acylphosphine oxide photoinitiator in this embodiment differs from that in Example 1 only in that an equal molar amount of diphenyl ether is replaced by a compound shown in the following formula:

[0139]

[0140] Other parameters and conditions are exactly the same as in Example 1.

[0141] MS:m / z[M+1] + =755.26 (Mw=754.79).

[0142] The H-NMR analysis results of the photoinitiator in this embodiment are as follows:

[0143] 1 H-NMR (400MHz, CDCl3): δ7.40~7.30(m,10H), 7.29~7.20(m,4H), 6.90~6.80(m,8H), 4.4(s,4H), 2.35(s,18H).

[0144] Example 7

[0145] The molecular formula of the acylphosphine oxide photoinitiator described in this embodiment is as follows:

[0146]

[0147] The preparation method of the acylphosphine oxide photoinitiator in this embodiment differs from that in Example 1 only in that an equal molar amount of diphenyl ether is replaced by diphenylmethane, and other parameters and conditions are exactly the same as those in Example 1.

[0148] MS:m / z[M+1] + =709.26 (Mw=708.76).

[0149] The H-NMR analysis results of the photoinitiator in this embodiment are as follows:

[0150] 1 H-NMR (400MHz, CDCl3): δ7.50~7.30(m,10H), 7.29~7.20(m,4H), 6.90~6.80(m,8H), 4.4(s,4H), 2.35(s,18H).

[0151] Comparative Example 1

[0152] This comparative example uses photoinitiator TPO as a control.

[0153] Comparative Example 2

[0154] The molecular formula of the photoinitiator in this comparative example is as follows:

[0155]

[0156] The preparation method of the acylphosphine oxide photoinitiator in this embodiment differs from that in Example 1 only in that an equal molar amount of diphenyl ether is replaced by biphenyl, and other parameters and conditions are exactly the same as those in Example 1.

[0157] MS:m / z[M+1] + =695.24 (Mw=694.73).

[0158] The H-NMR analysis results of the photoinitiator in this comparative example are shown below:

[0159] 1 H-NMR (400MHz, CDCl3): δ7.80~7.30(m,18H), 6.92~6.85(m,4H), 2.45(s,18H).

[0160] Performance testing:

[0161] The photoinitiators obtained in the examples and comparative examples were tested for photoinitiator activity and mobility, and the test conditions were as follows:

[0162] Test formula and working conditions

[0163] formula:

[0164] Epoxypropylene carboxylic acid resin (molecular weight 700-800) 36wt%

[0165] Pentaerythritol triacrylate 60wt%

[0166] Example product (or comparative example product) 4.0wt%;

[0167] Working conditions and evaluation

[0168] The above mixture was applied to a glass plate using a squeegee. The film was cured using either a standard mercury vapor lamp or an LED lamp (360W, 395nm light source, 5s exposure). After the glass plate was passed under the lamp at a speed of 100 m / min, the film was found to be firm to wiping. The number of passes under the lamp required for complete surface cure was recorded. The results are shown in Table 1.

[0169] Table 1

[0170]

[0171] Mobility test conditions:

[0172] The formulation of the photocurable composition for the mobility test is the same as the formulation for the photoinitiator activity test described above; a film is applied on the coating with a squeegee and the film is cured by irradiation with a standard mercury vapor lamp. 2) The cured coated sample and a filter paper with a diameter of 10 cm were placed between two stainless steel sheets and maintained under five tons of pressure for 72 hours. The filter paper was extracted with THF and heated under reflux for three hours. The content of the sample and the comparative example was determined by HPLC. The results are shown in Table 2.

[0173] Table 2

[0174]

[0175]

[0176] It can be seen from the data in Tables 1 and 2 above that the acylphosphine oxide photoinitiator of the present invention has high photoinitiating activity, and its mobility is significantly reduced compared to the photoinitiator TPO.

[0177] By comparing Examples 1-4 and 6-7, it can be seen that when the photoinitiator molecule contains two molecules of symmetrically distributed acylphosphine oxide groups, it has a higher photoinitiator activity; this further illustrates that the present invention uses a specific group as a connecting group to connect the two acylphosphine oxide groups, and the synergistic effect between the two enhances the initiation activity of the photoinitiator; and wherein, when the connecting group X is selected from O, -NR and -O(CH2)2O-, its photoinitiator activity is best; and further preferably O or -O(CH2)2O-; on the contrary, by comparing the photoinitiator TPO and the photoinitiator in Comparative Example 2, it can be seen that although Comparative Example 2 also contains two acylphosphine oxides, its photoinitiator activity is significantly reduced compared to TPO.

[0178] It can be seen from Examples 3-4 that when the linking group X is selected from -NR, R is further preferably an alkyl group or a 4-substituted phenyl group; and it can be seen from the photoinitiator in Example 6 that it contains three symmetrically distributed acylphosphine oxide groups. The synergistic effect between the three makes it have higher photoinitiator activity and lower mobility than the photoinitiator TPO, but its mobility is higher than that of the photoinitiator having two symmetrically distributed acylphosphine oxide groups.

[0179] The applicant declares that the above is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing an acylphosphine oxide photoinitiator, characterized in that: The molecular formula of the acylphosphine oxide photoinitiator is shown below: Wherein, X is selected from O, S, -(CH2) m - or any one of the groups represented by the following formula (b); m is selected from 1 to 4, n is selected from 1 to 4; The preparation method comprises the following steps: (1) mixing phenylphosphine dichloride, a compound represented by formula (e), and a catalyst, and heating the mixture to react to obtain a mixture containing an intermediate product; Wherein, Y is selected from O, S, -(CH2) m - or any one of the groups represented by formula (b); (2) hydrolyzing the mixture obtained in step (1), separating the liquids, and obtaining an organic phase; (3) adding aldehyde to the organic phase in step (2) to carry out the reaction; (4) The reaction product in step (3) is subjected to an oxidation reaction to obtain the acylphosphine oxide photoinitiator.

2. The preparation method according to claim 1, wherein X is selected from O, -(CH2) m - or any one of the groups represented by formula (b), m is selected from 1-4, and n is selected from 1-4.

3. The preparation method according to claim 2, wherein X is -(CH2) m -, m is 1 or 2.

4. The preparation method according to claim 2, wherein X is a group - represented by formula (b), and n is 1 or 2.

5. The preparation method according to claim 1, wherein The acylphosphine oxide photoinitiator includes any one of the following structures; 6. The preparation method according to claim 1, wherein The catalyst in step (1) includes aluminum trichloride.

7. The preparation method according to claim 1, wherein The temperature of the heating reaction in step (1) is 100°C to 150°C.

8. The preparation method according to claim 7, wherein The temperature of the heating reaction in step (1) is 110°C to 130°C.

9. The preparation method according to claim 1, wherein In step (1), the molar ratio of phenylphosphine dichloride, the compound represented by formula (e) and the catalyst is 2-3:1:2-4.

10. The preparation method according to claim 1, wherein Before the hydrolysis in step (2), the mixture in step (1) is mixed with a non-polar solvent for dilution.

11. The preparation method according to claim 10, characterized in that The step of diluting the mixture also includes cooling the temperature.

12. The preparation method according to claim 10, wherein The non-polar solvent includes at least one of toluene, xylene, ethylbenzene and chlorobenzene.

13. The preparation method according to claim 10, wherein The hydrolysis method comprises dropwise adding the mixed solution obtained by diluting the mixture in step (1) into water.

14. The preparation method according to claim 1, wherein The temperature during the hydrolysis process is ≤20°C.

15. The preparation method according to claim 14, wherein The hydrolysis process is accompanied by stirring.

16. The preparation method according to claim 1, wherein The ratio of the molar amount of methyl aldehyde added in step (3) to the molar amount of phenylphosphine dichloride in step (1) is 0.8 to 1.5:

1.

17. The preparation method according to claim 1, wherein The reaction temperature in step (3) is 15°C to 40°C.

18. The preparation method according to claim 1, wherein The reaction temperature in step (3) is 20°C to 35°C.

19. The preparation method according to claim 1, wherein The reaction time in step (3) is 2h to 12h.

20. The preparation method according to claim 1, wherein After the reaction in step (3) is completed, the temperature is further lowered to 10°C to 15°C.

21. The preparation method according to claim 1, wherein The method for the oxidation reaction in step (4) comprises adding a catalyst and an oxidant to the reaction product in step (3), mixing, and conducting an oxidation reaction.

22. The preparation method according to claim 21, wherein The catalyst in the oxidation reaction is selected from at least one of a vanadium-containing catalyst, a heteropolyacid catalyst and a heteropolyacid salt catalyst.

23. The preparation method according to claim 21, wherein The amount of catalyst used in the oxidation reaction is selected from 0.1% to 10% of the mass of phenylphosphine dichloride.

24. The preparation method according to claim 21, wherein The oxidizing agent is selected from peroxides.

25. The preparation method according to claim 24, characterized in that The peroxide is hydrogen peroxide and / or tert-butyl peroxide.

26. The preparation method according to claim 21, wherein The amount of the oxidant used in the oxidation reaction is 1-3 times the amount of the phenylphosphine dichloride substance.

27. The preparation method according to claim 21, wherein The oxidant is added dropwise.

28. The preparation method according to claim 1, wherein After the oxidation reaction in step (4), the process further includes alkali washing, liquid separation, water washing and desolventizing.

29. The preparation method according to claim 28, wherein The alkali solution used in the alkali washing includes at least one of a sodium hydroxide aqueous solution, a sodium carbonate aqueous solution or a sodium bicarbonate aqueous solution.

30. The preparation method according to claim 28, wherein The temperature of the alkali washing is ≤20°C.

31. The preparation method according to claim 28, wherein The alkali solution used in the alkali washing is selected from a sodium hydroxide aqueous solution with a concentration of 15wt% to 25wt%.

32. The preparation method according to claim 28, wherein The alkali washing process is accompanied by stirring.

33. The preparation method according to claim 28, wherein The organic phase obtained from the end point of the water washing to the separation is neutral.

34. The preparation method according to claim 1, wherein The method comprises the following steps: (I) mixing phenylphosphine dichloride, a compound represented by formula (e), and aluminum chloride in a reaction vessel, heating to 100-150° C. for reaction, and cooling to obtain a mixture containing an intermediate product; Wherein, Y is selected from O, S, -(CH2) m - or any one of the groups represented by formula (b); (II) diluting the mixture in step (I) with a non-polar solvent to obtain a mixed solution, then adding the mixed solution dropwise to water at a temperature of ≤20°C with stirring for hydrolysis, and separating the liquids to obtain an organic phase; (III) adding rice aldehyde to the organic phase in step (II), reacting at 15°C to 40°C for 2h to 12h, and then cooling to 10-15°C; (IV) adding a catalyst to the reaction product in step (III), and then dropwise adding a peroxide to carry out an oxidation reaction; (V) adding a 15 wt % to 25 wt % aqueous sodium hydroxide solution to the reaction product in step (IV) at a temperature of ≤ 20° C. with stirring, separating the layers, washing the organic phase with water until neutral, and desolventizing to obtain the acylphosphine oxide photoinitiator.

35. Use of an acylphosphine oxide photoinitiator, characterized in that: The molecular formula of the acylphosphine oxide photoinitiator is as follows: Wherein, X is selected from O, S or -(CH2) m Any one of -; m is selected from 1 to 4; The acylphosphine oxide photoinitiator is used in a photocuring system with a wavelength of 300nm to 450nm.

36. The use according to claim 35, characterized in that The acylphosphine oxide photoinitiator is used in the fields of ink, coating, tooth restoration, 3D printing, and pipeline repair.

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