Photocurable organopolysiloxane resins

Abstract

In one embodiment, the present invention is a composition comprising a bisacylphosphine oxide photoinitiator, a mercapto-C3-C12-alkyl functionalized organopolysiloxane, and an olefin functionalized organopolysiloxane, as described herein. The composition of the present invention provides a uniform coating that achieves an acceptable depth of cure by UV or LED irradiation.

Description

Background Technology

[0001] This invention relates to a photocurable polyorganosiloxane resin and a diacid phosphine oxide photoinitiator.

[0002] UV or LED-induced polymer curing is desirable for high-throughput processing. Curing is induced by photoinitiators compatible with the polymer; however, compatibility is a long-standing and unresolved issue for organopolysiloxane curing systems. Poorly compatible photoinitiators are undesirable as curing agents because they can decouple from the silicone matrix during storage, leading to ineffective curing, undesirable haze, and coating defects in the cured product.

[0003] US 10,597,413 B2 (Tan) describes an acylphosphine oxide substituted with a -CH2-O-Si(OR)3 group, with typical examples being the following compounds:

[0004]

[0005] Although Tan disclosed that these photoinitiators solved the long-standing solubility problem, another issue was clearly introduced: the susceptibility of acid cleavage of the silyl ether bond (CH2-OSi), which makes the photoinitiator incompatible with the silicone matrix. Therefore, it would be advantageous to achieve both solubility and maintain stability in the field of photoinitiation in silicone systems. Summary of the Invention

[0006] This invention provides a photoinitiator comprising a diacylphosphine oxide and a mercapto-C3-C... 12 - Compositions of alkyl-functionalized organopolysiloxanes and olefin-functionalized organopolysiloxanes are used to address the needs in the art, wherein the diacylphosphine oxide photoinitiator is a compound of formula 1:

[0007]

[0008] Where m is 0, 1, 2 or 3; and n is 0, 1 or 2;

[0009] R 1 -phenyl-(R 3 ) n -C(O)-phenyl-(R 2 ) m -O-C1-C 20 -alkyl or -O(CH2CH2O) x -H, where x is from 1 to 20;

[0010] Each R 2 Independently, it is C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R 2Adjacent R on the benzene ring 2 Together they form a 1,3-dioxolane group or a 1,4-dioxane group;

[0011] Each R 3 Independently, it is a C1-C6-alkyl or C1-C6-alkoxy group;

[0012] R 4 for

[0013] i)–(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y; where

[0014] p is 0 or 1, provided that when p is 0, q is 3 to 12, and when p is 1, q is 2 to 12.

[0015] r ranges from 3 to 300;

[0016] X is CH2CH2 or CH(CH3);

[0017] s is 0 or 1, provided that when s is 0, Y is SiMe2H, and when s is 1, Y is Si(OMe)3; SiMe3; Si(OEt)3; SiMe2OMe; SiMe2OEt; Si(OSiMe3)3; SiMe(OSiMe3)2; SiMe2(OSiMe3); or

[0018] ;

[0019] The dashed lines represent the attachment points from Y to X; and

[0020] Each R 5 Independently, it is a C1-C6-alkyl or phenyl group;

[0021] Or R 4 for

[0022] ii)–(Si(Me2)) p (CH2) t -Z; where

[0023] p is either 0 or 1, provided that when p is 0, t is 4, and when p is 1, t is 2; and

[0024] Z is:

[0025]

[0026] The dashed line represents the path from Z to (CH2). tAttachment point.

[0027] The compositions of the present invention address the needs in the art by providing organopolysiloxane compositions that can be cured by UV or LED to form a haze-free, defect-free coating. Detailed Implementation

[0028] This invention relates to a composition comprising a diacylphosphine oxide photoinitiator and a thiol-C3-C... 12 -A composition of alkyl-functionalized organopolysiloxanes and olefin-functionalized organopolysiloxanes, wherein the diacylphosphine oxide photoinitiator is a compound of formula 1:

[0029]

[0030] Where m is 0, 1, 2 or 3; and n is 0, 1 or 2;

[0031] R 1 -phenyl-(R 3 ) n -C(O)-phenyl-(R 2 ) m -O-C1-C 20 -alkyl or -O(CH2CH2O) x -H, where x is from 1 to 20;

[0032] Each R 2 Independently, it is C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R 2 Adjacent R on the benzene ring 2 Together they form a 1,3-dioxolane group or a 1,4-dioxane group;

[0033] Each R 3 Independently, it is a C1-C6-alkyl or C1-C6-alkoxy group;

[0034] R 4 for

[0035] i)–(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y; where

[0036] p is 0 or 1, provided that when p is 0, q is 3 to 12, and when p is 1, q is 2 to 12.

[0037] r ranges from 3 to 300;

[0038] X is CH2CH2 or CH(CH3);

[0039] s is 0 or 1, provided that when s is 0, Y is SiMe2H, and when s is 1, Y is Si(OMe)3; SiMe3; Si(OEt)3; SiMe2OMe; SiMe2OEt; Si(OSiMe3)3; SiMe(OSiMe3)2; SiMe2(OSiMe3); or

[0040] ;

[0041] The dashed lines represent the attachment points from Y to X; and

[0042] Each R 5 Independently, it is a C1-C6-alkyl or phenyl group;

[0043] Or R 4 for

[0044] ii)–(Si(Me2)) p (CH2) t -Z; where

[0045] p is either 0 or 1, provided that when p is 0, t is 4, and when p is 1, t is 2; and

[0046] Z is:

[0047]

[0048] The dashed line represents the path from Z to (CH2). t Attachment point.

[0049] In one respect, R 1 -C(O)-phenyl-(R 2 ) m Preferred R 1 Examples of functional groups are represented by the following structures:

[0050]

[0051] In one respect, R 4 –(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y; on the other hand, each R 5 It is methyl. In one aspect, when p is 0, q is 3 or 4; in the other aspect, when p is 1, q is 2; r is 3 or 6 or 10 to 300 or 200 or 100 or 50.

[0052] The compounds of formula I can be prepared as described in schemes 1 to 3. In R 1 -C(O)-phenyl-(R 2 ) m And R 4 When the compound is located at the para position on the benzene ring, compounds of formula I can be prepared according to Scheme 1. The reaction conditions for each step are described in the experimental section.

[0053] Option 1

[0054]

[0055] When p is 0, q' ranges from 1 to 10, and when p is 1, q' ranges from 0 to 10.

[0056] Alternatively, in R 1 -C(O)-phenyl-(R 2 ) m In this case, the compounds of the present invention can be prepared by reacting the final intermediate with compound A or B:

[0057]

[0058] Where X is CH2CH2 or CH(CH3).

[0059] When p is 1, the first compound in Scheme 1 can be prepared by contacting dibromobenzene (specifically, p-dibromobenzene) with vinyldimethylsilyl chloride in the presence of n-butyllithium in the first step to form the following intermediate:

[0060]

[0061] Where b is between 0 and 10.

[0062] With p = 0, the first compound (especially with q' = 2) can be prepared as follows: Li, Y.-L.; Song, D.-P.; Pan, L.; Ma, Z.; Li, Y.-S. Polym. Chem. 2019, 10, 6368-6378.

[0063] In R 1 -O-C1-C 20 -alkyl or -O(CH2CH2O) x In the case of -H, compounds of formula I can be prepared according to scheme 2.

[0064] Option 2

[0065]

[0066] Where R is HO-C1-C 20 -alkyl or HO(CH2CH2O) x -H.

[0067] In R 1 -phenyl-(R 3 ) n In this case, compounds of formula I can be prepared according to scheme 3.

[0068] Option 3

[0069]

[0070] Based on the weight of the composition, the concentration of the photoinitiator core moiety of the photoinitiator is typically in the range of 0.01 wt%, 0.05 wt%, or 0.1 wt% to 10 wt%, or 4 wt%, or 2 wt%. As used herein, "photoinitiator core" refers to the following fragment of a bisacylphosphine oxide photoinitiator:

[0071]

[0072] When p is 0, q' ranges from 1 to 10, and when p is 1, q' ranges from 0 to 10.

[0073] Thiol-C3-C 12 -Alkyl-functionalized organopolysiloxanes can be linear or branched. For example, mercapto-C3-C 12 -Alkyl-functionalized organopolysiloxanes may contain one or more silicon atoms attached to two oxygen atoms and two C1-C6-alkyl groups, two phenyl groups, or one C1-C6-alkyl group and one phenyl group (“D” units); one or more silicon atoms attached to three oxygen atoms and one C1-C6-alkyl group or one phenyl group (“T” units); or one or more silicon atoms attached to three oxygen atoms (“Q” units). A class of mercapto-C3-C... 12 - An example of an alkyl-functionalized organopolysiloxane is represented by Formula 2:

[0074]

[0075] Each R 1' -CH2CH2(CH2) z -SH; for each R 2' Independently methyl or -CH2CH2(CH2) z -SH; x is 2 to 1000; y is 0 to 100; and each z is 1 to 10, provided that R is 0 when y is 0. 2'At least one of the groups is -CH2CH2(CH2). z -SH; and another condition is that in each R 2' When z is methyl, y is 1 to 100. Preferably, z is 1 to 8; more preferably, z is 1 to 4; most preferably, z is 1. Preferably, x is 10 or 20 to 500 or 100. Preferably, when y is 0, both R 2' All functional groups are -CH2CH2(CH2). z -SH group; more preferably, when y is 0, the two R groups 2' All groups are -CH2CH2CH2SH groups. Similarly, in the two R groups... 2' When all groups are methyl, R 1' The group is preferably a -CH2CH2CH2SH group.

[0076] Based on thiol-C3-C 12 -Combined gravimetric analysis of alkyl-functionalized organopolysiloxanes and olefin-functionalized organopolysiloxanes, mercapto-C3-C 12 The concentration of alkyl-functionalized organopolysiloxanes is typically in the range of 1% or 3% by weight to 70% or 30% or 20% by weight.

[0077] Examples of olefin-functionalized organopolysiloxanes include divinyl, diallyl, and dialhexenyl-functionalized organopolysiloxanes. An example of a divinyl-functionalized polydimethylsiloxane is shown in Formula 3:

[0078]

[0079] Where a ranges from 10 to 10,000. Based on thiol-C3-C 12 - A combination of alkyl-functionalized and olefin-functionalized organopolysiloxanes by weight, wherein the concentration of the olefin-functionalized organopolysiloxane is typically in the range of 5% or 30% or 70% by weight to 99% or 90% by weight. Commercially available organopolysiloxanes include XIAMETER. ™ RBL-9119 organopolysiloxane and XIAMETER ™ RBL-9128 is an organopolysiloxane (XIAMETER is a trademark of The Dow Chemical Company or its affiliates).

[0080] Another example of an olefin-functionalized organopolysiloxane includes an organopolysiloxane having both Si-C1-C6-alkoxysilyl and Si-alkenyl functional groups, which can be used in conjunction with or in place of the compound of Formula 3. Examples of organopolysiloxanes having both Si-C1-C6-alkoxysilyl and Si-alkenyl functional groups are disclosed in WO 2020 / 076620 A1. One such bifunctional compound is the compound of Formula 4:

[0081]

[0082] Where b ranges from 1 to 5000.

[0083] Additionally, the composition may also contain organopolysiloxanes having C1-C6-alkoxysilyl groups.

[0084] In cases where moisture curing is required, the composition advantageously comprises a moisture curing catalyst, such as a titanium catalyst, and an example thereof is a titanium dioxide acetoacetate complex, which is commercially available as Tyzor PITA-SM organotitanate.

[0085] The compositions of the present invention can be UV-cured or moisture-cured in the presence of a single compound having a bis-Si-alkenyl / Si-alkoxy functional group or a mixture of compounds having Si-alkenyl and Si-alkoxy functional groups.

[0086] Example

[0087] Intermediate Example 1 - Preparation of M'D 14 M' Polysiloxane-substituted photoinitiator

[0088] A. Preparation of (4-(but-3-en-1-yl)phenyl)dichlorophosphine

[0089] In a glove box, 1-bromo-4-(but-3-en-1-yl)benzene (17.1 g), anhydrous THF (118 mL), and anhydrous diethyl ether (37 mL) were added to a 500 mL round-bottom flask. The flask was sealed and transferred to a fume hood. The mixture was stirred under N2 and cooled to -78 °C, then n-butyllithium (n-BuLi, 2.5 M in hexane, 34.0 mL) was added dropwise to the mixture. The mixture was stirred for 30 minutes, followed by chlorobis(diethylamino)phosphine (17.9 mL, 85.1 mmol). The mixture was stirred for 20 minutes and allowed to heat to ambient temperature. The solution was poured into a separating funnel containing diethyl ether and water. The phases were separated, and the aqueous phase was extracted with several fractions of diethyl ether. The combined organic fractions were washed with brine, dried over MgSO4, and concentrated under vacuum.

[0090] The crude oily substance was transferred to a 1000-mL round-bottom flask, which was then placed in a glove box. The oily substance was dissolved in anhydrous diethyl ether (100 mL). The mixture was stirred and treated dropwise with HCl (2.0 M in diethyl ether, 162 mL, 324 mmol, 4.00 equivalent), and a white solid precipitated. After 2 hours, the slurry was filtered, and the filtrate was concentrated. A colorless oily substance (15.9 g, 84%) was separated and used in the next step without further purification.

[0091] B. Preparation of (4-(but-3-en-1-yl)phenyl)phosphine

[0092] In a glove box, 100 mL of diethyl ether and 19.8 mL of LiAlH4 (2.0 M in THF, 39.6 mmol, 0.60 equivalent) were added dropwise to a 500 mL wide-mouth flask. The solution was stirred vigorously, and over 10 minutes, 65 mL of diethyl ether containing (15.4 g, 66.1 mmol, 1.00 equivalent) dichlorophosphine was added dropwise. The mixture was stirred for 30 minutes, after which solid sodium sulfate (25.5 g, 79.3 mmol, 1.20 equivalent) was carefully added. The mixture was stirred for 60 minutes, and the liquid was decanted and filtered through a 0.45 µm syringe filter and concentrated to give a colorless oil (9.73 g, 90%), which was used in the next step without further purification.

[0093] C. Preparation of ((4-(but-3-en-1-yl)phenyl)phosphoryl)bis(metrimethylmethyl ketone)

[0094] In a glove box, a solution of (4-(but-3-en-1-yl)phenyl)phosphine (9.73 g, 59.3 mmol, 1.00 equivalent) in anhydrous THF (300 mL) was treated with sodium tert-butoxide (NatOBu, 11.4 g, 118 mmol, 2.00 equivalent), followed by dropwise addition of 2,4,6-trimethylbenzoyl chloride (19.8 mL, 118 mmol, 2.00 equivalent) to the mixture. The mixture was stirred overnight. Crude 31P NMR spectroscopy analysis indicated that phosphine was partially consumed. Additional amounts of NatOBu (3.99 g) and benzoyl chloride (6.9 mL) were added to the reaction mixture. After 5 hours, the mixture was filtered to remove sodium chloride, and the filtrate was removed from the glove box and concentrated under vacuum. The crude residue was dissolved in dichloromethane (200 mL), and the solution was treated with hydrogen peroxide (6.0 mL, 30 wt%). The mixture was stirred overnight at ambient temperature, then treated with an aqueous sodium bisulfite solution (100 mL) and stirred until the organic phase was negative relative to the peroxide stripping test. The phases were separated and concentrated with diatomaceous earth for silica gel chromatography (0% to 50% EtOAc / hexane). A yellow oily substance (13 g) containing the product and some other impurities was separated. A second column purification was performed, thereby separating the intermediate Example 3 (11.3 g) as a yellow oily substance.

[0095] D. Preparation of M'D 14 M' Polysiloxane-substituted photoinitiator

[0096] A formulation of ((4-(but-3-en-1-yl)phenyl)phosphoyl)bis(trimethylmethyl ketone) (0.07 g) was mixed with anhydrous hexane (3.0 mL) and M'D 14 M' polysiloxane (0.99 g) was mixed in a glove box. The mixture was stirred at 50 °C until the solids dissolved. Karstedt's Catalyst (0.03 mL of xylene containing 2 wt% Pt) was added, and the mixture was stirred overnight. 1 The consumption of olefins was monitored by 1H NMR spectroscopy, and additional Castiglione catalyst was added until < 5% of olefins remained. Vinyltrimethoxysilane was added to react with the remaining Si-H groups.

[0097] The volatiles were removed using a vacuum pump, leaving an amber-colored oily substance. The mixture of the following products was determined to contain 4.0 wt% of photoinitiator.

[0098]

[0099] Intermediate Example 2 - Preparation of M'D 14 M' Polysiloxane-substituted photoinitiator

[0100] A. Preparation of (4-bromophenyl)dimethyl(vinyl)silane

[0101] Under a nitrogen blanket, anhydrous THF (425 mL) and 1,4-dibromobenzene (20.0 g, 84.8 mmol, 1.00 equivalent) were added to a 1000-mL three-necked round-bottom flask equipped with a separate funnel. The mixture was stirred and cooled to -78 °C. An n-BuLi solution (2.5 M in hexane, 35.6 mL, 89.0 mmol, 1.05 equivalent) was added dropwise to the dibromobenzene solution over 25 minutes. After the n-BuLi solution addition was complete, stirring was continued for another 50 minutes.

[0102] Dichloromethylvinylsilane (12.9 mL, 93.3 mmol, 1.10 equivalents) was added dropwise to the reaction mixture with stirring. The mixture was gradually heated to room temperature over 1 hour, and then quenched with an aqueous solution of ammonium chloride. The product was extracted with several fractions of ethyl acetate. The combined organic fractions were dried over sodium sulfate and concentrated. The crude oil was purified under vacuum (450 mTorr, 52 °C–60 °C) to give (4-bromophenyl)dimethyl(vinyl)silane (18.75 g) as a colorless oil.

[0103] B. Preparation of ((4-(dimethyl(vinyl)silyl)phenyl)phosphoryl)bis(trimethylmethyl ketone)

[0104] In a glove box, (4-bromophenyl)dimethyl(vinyl)silane (4.31 g, 17.9 mmol, 1.00 equivalent), anhydrous THF (26 mL), and anhydrous diethyl ether (8 mL) were added to a 250 mL round-bottom flask. The flask was sealed and transferred to a fume hood. The mixture was stirred under nitrogen and cooled to -78 °C. At this point, n-BuLi (2.5 M in hexane, 7.51 mL, 18.8 mmol, 1.05 equivalent) was added dropwise. The mixture was stirred for 30 minutes, followed by the addition of chlorobis(diisopropylamino)phosphine (5.01 g, 18.8 mmol, 1.05 equivalent) in solid form. The mixture was stirred and allowed to heat to ambient temperature over 2 hours. The solution was poured into a separating funnel containing diethyl ether and water. The phases were separated, and the aqueous phase was extracted with several fractions of diethyl ether. The combined organic fractions were washed with brine, dried over MgSO4, and concentrated by rotary evaporation.

[0105] Transfer the crude oily substance to a 250-mL round-bottom flask and place the flask in a glove box. Dissolve the oily substance in anhydrous diethyl ether (20 mL). Seal the flask and transfer it to a fume hood. Stir the mixture under N2 and cool to 0°C. Then add HCl dropwise (2.0 M in diethyl ether, 35.7 mL, 71.5 mmol, 4.00 equivalent), and a white solid precipitates. Continue stirring for 2 hours, filter the slurry, and concentrate the filtrate. Mix the crude residue with diethyl ether and hexane, and filter again. Concentrate the filtrate to give a colorless oily substance (4.59 g). Use the crude material for the next step without further purification.

[0106] In a glove box, under vigorous stirring, diethyl ether (44 mL) and LiAlH4 (2.0 M in THF, 5.23 mL, 10.5 mmol, 0.60 equivalent) were added dropwise to the LiAlH4 solution over 5 minutes. The mixture was stirred for 30 minutes, after which solid sodium sulfate (6.74 g, 20.9 mmol, 1.20 equivalent) was carefully added. Stirring was continued for 14 hours, after which the solution was filtered and the filtrate was concentrated to give 2.71 g of crude product as a colorless oil. The crude material was used in the next step without further purification.

[0107] The solution of crude material (2.71 g) from the previous step in anhydrous THF (70 mL) was treated with anhydrous NatOBu (2.68 g, 27.9 mmol, 2.00 equivalents), followed by dropwise addition of 2,4,6-trimethylbenzoyl chloride (4.65 mL, 27.9 mmol, 2.00 equivalents). The mixture was stirred for 3 hours and then filtered to remove sodium chloride.

[0108] The filtrate was removed from the glove box and concentrated under vacuum. The crude residue was dissolved in dichloromethane (50 mL), and the solution was treated with hydrogen peroxide (1.4 mL, 30 wt%). The mixture was stirred overnight at ambient temperature and then treated with an aqueous sodium bisulfite solution (30 mL). The phases were separated, and the organic phase was concentrated in the presence of silica gel for silica gel liquid chromatography (0% to 50% EtOAc / hexane). A yellow oily substance, ((4-(dimethyl(vinyl)silyl)phenyl)phosphoryl)bis(trimethylmethyl ketone) (1.98 g), was separated, which solidified upon standing.

[0109] C. Preparation of M'D 14 M' Polysiloxane-substituted photoinitiator

[0110] 0.10 g of ((4-(dimethyl(vinyl)silyl)phenyl)phosphoryl)bis(trimethylmethyl ketone) was mixed with anhydrous toluene (1.5 mL) and M'D 14 M' polysiloxane (0.24 g) was mixed in a glove box. The mixture was stirred at 80 °C until the solids dissolved. Castiglione catalyst (0.012 mL containing 2 wt% Pt xylene) was added to the mixture, and stirring was continued for 1 hour. 1 The consumption of olefins was monitored by 1H NMR spectroscopy, and additional Castiglione catalyst was added until < 5% of olefins remained. Vinyltrimethoxysilane was added to react with the remaining Si-H groups. The volatiles were removed under vacuum, leaving an amber oil. The mixture of the following products was determined to contain 30.0% by weight of photoinitiator.

[0111]

[0112] Example 1 - Preparation of a dual-curable organopolysiloxane composition

[0113] By adding the compound of formula 2 (7.05 pbw, each R) to a 100-mL dental cup 2' It is methyl, R 1' A dual-curable organopolysiloxane composition was prepared by blending the following compounds: HS-CH2CH2CH2- (x=5, y=43); compound 3 (40.66 pbw, a=766); compound 4 (28.4 pbw, each b=30); and pyrolytic silica filler (17.43 pbw). The blends were mixed at 1000 rpm for 20 seconds, then further mixed at 2000 rpm for 45 seconds. A mixture of methyltrimethoxysilane (3.74 pbw) and butylated hydroxytoluene (0.56 pbw) was added to the blend, and mixing was continued at 2000 rpm for 30 seconds. Then, methyltrimethoxysilane (0.5 pbw), intermediate Example 1 photoinitiator (1.03 pbw), and TyzorPITA-SM (0.10 pbw) were added to the blend, and mixing was continued at 2000 rpm for 30 seconds. The composition was then packaged in three 30-mL syringes and degassed, and then vacuum-sealed in an aluminum bag to prevent moisture and light.

[0114] Example 2 – Preparation of a dual-curable organopolysiloxane composition

[0115] The preparation described in Example 1 was carried out in essentially the same manner, except that the intermediate photoinitiator of Example 2 (1.03 pbw) was used.

[0116] Comparative Example 1 – Preparation of a dual-curable organopolysiloxane composition

[0117] The preparation described in Example 1 was carried out in essentially the same manner, except that Irgacure 819 bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide photoinitiator (1.03 pbw, Irgacure 819) was used.

[0118] UV curing process

[0119] Use a Colight UV curing oven equipped with a mercury lamp at 300mW / cm². 2 Strength and 2J / cm 2 The sample is cured using doses of UVA and UVB wavelengths.

[0120] LED curing process

[0121] Using the Uvitron Skyray 800 LED floodlight curing system, with a 365-nm LED oven at 500mW / cm², 2 Strength and 10 J / cm 2 The irradiation dose was used to solidify the sample.

[0122] UV curing depth measurement

[0123] The formulation is filled into a Teflon block with holes 25 mm in diameter and 20 mm deep. The coating is then exposed to UV or LED irradiation. The sample is removed from the holes, and any uncured material is removed with a paper towel so that the curing depth can be measured with a ruler.

[0124] Table 1 illustrates the formulation appearance, coating appearance, and curing depth of the samples cured by UV irradiation. A curing depth >3 mm is considered acceptable.

[0125]

[0126] In the formulation of Comparative Example 1, the precipitated particles were obvious, resulting in an uneven coating upon curing and aggregate defects; in contrast, the exemplary formulation of the present invention forms a stable emulsion with no visible signs of precipitated particles, and the resulting coating is uniform.

[0127] Table 2 illustrates the formulation appearance, coating appearance, and curing depth of the samples cured by LED irradiation. A curing depth >3 mm is considered acceptable.

[0128]

[0129] Data shows that compositions containing the photoinitiator of this invention produce uniform formulations and coatings with acceptable curing depths under both types of irradiation. In contrast, compositions containing the Irgacure 819 photoinitiator are non-uniform and produce uneven coatings.

Claims

1. A composition comprising a bisacylphosphine oxide photoinitiator and a thiol-C3-C... 12 - Alkyl-functionalized organopolysiloxanes and olefin-functionalized organopolysiloxanes, wherein the diacylphosphine oxide photoinitiator is a compound of formula 1: Where m is 0, 1, 2 or 3; and n is 0, 1 or 2; R 1 -phenyl-(R 3 ) n -C(O)-phenyl-(R 2 ) m -O-C1-C 20 -alkyl or -O(CH2CH2O) x -H, where x is from 1 to 20; Each R 2 Independently, it is C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R 2 Adjacent R on the benzene ring 2 Together they form a 1,3-dioxolane group or a 1,4-dioxane group; Each R 3 Independently, it is a C1-C6-alkyl or C1-C6-alkoxy group; R 4 for i)–(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y; where p is 0 or 1, provided that when p is 0, q is 3 to 12, and when p is 1, q is 2 to 12; r ranges from 3 to 300; X is CH2CH2 or CH(CH3); s is 0 or 1, provided that when s is 0, Y is SiMe2H, and when s is 1, Y is Si(OMe)3; SiMe3; Si(OEt)3; SiMe2OMe; SiMe2OEt; Si(OSiMe3)3; SiMe(OSiMe3)2; SiMe2(OSiMe3); or ； The dashed lines represent the attachment points from Y to X; and Each R 5 Independently, it is a C1-C6-alkyl or phenyl group; Or R 4 for ii)–(Si(Me2)) p (CH2) t -Z; where p is either 0 or 1, provided that when p is 0, t is 4, and when p is 1, t is 2; and Z is: The dashed line represents the path from Z to (CH2). t Attachment point.

2. The composition according to claim 1, wherein the thiol-C3-C 12 - Alkyl-functionalized organopolysiloxanes are represented by Formula 2: Each R 1' -CH2CH2(CH2) z -SH; each R 2' Independently methyl or -CH2CH2(CH2) z -SH; x is 2 to 1000; y is 0 to 100; and each z is 1 to 10, provided that R is 0 when y is 0. 2' At least one of the groups is -CH2CH2(CH2). z -SH; and another condition is that in each R 2' When methyl is used, y is 1 to 100; and the olefin-functionalized organopolysiloxane is represented by Formula 3: Where a ranges from 10 to 10,000.

3. The composition according to claim 2, wherein z is 1; R 1 -C(O)-phenyl-(R 2 ) m ; Each R 2 For methyl groups, each m is 3, each n is 0, and R 4 –(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y, where each R 5 X is methyl, r is CH2CH2, and q is 10 to 200; when p is 0, q is 3, and when p is 1, q is 2; and Y is Si(OMe)3 or The dashed lines represent the attachment points from the CH2CH2 group.

4. The composition according to claim 2, wherein z is 1; R 1 -C(O)-phenyl-(R 2 ) m ; Each R 2 For methyl groups, each m is 3, each n is 0, and R 4 –(Si(Me2)) p (CH2) t -Z.

5. The composition according to claim 1, wherein z is 1; R 1 -C(O)-phenyl-(R 2 ) m ; Each R 2 For methyl groups, each m is 3, each n is 0, and R 4 –(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y, where each R 5 X is methyl, r is CH2CH2, and q is 10 to 200; when p is 0, q is 3, and when p is 1, q is 2; and Y is Si(OMe)3 or The dashed lines represent attachment points from the CH2CH2 group; and the olefin-functionalized organopolysiloxanes are further functionalized with Si-C1-C6-alkoxysilyl groups.

6. The composition according to any one of claims 2 to 4, wherein the composition further comprises an organopolysiloxane functionalized with a Si-C1-C6-alkoxysilyl group.

7. The composition according to claim 6, wherein the organopolysiloxane functionalized with a Si-C1-C6-alkoxysilyl group is further functionalized with a Si-vinyl group, wherein the C1-C6-alkoxysilyl group is a trimethoxysilyl group.

8. The composition according to claim 7, wherein the organopolysiloxane functionalized with trimethoxysilyl groups and vinyl groups is represented by the following formula: Where b ranges from 1 to 5000.

9. The composition according to claim 1, wherein the diacylphosphine oxide photoinitiator is selected from the group consisting of: Where r ranges from 6 to 50.

10. The composition of claim 8, wherein the bisacylphosphine oxide photoinitiator is selected from the group consisting of: Where r ranges from 6 to 50.

Images