Photocurable organopolysiloxane resins

Abstract

The present invention relates to a composition comprising a bisacylphosphine photoinitiator, as described herein, and a polyacrylate functionalized organosiloxane. The composition of the present invention provides a uniform coating that achieves an acceptable depth of cure by UV or LED irradiation.

Description

BACKGROUND

[0001] The present invention relates to a photocurable polyorganosiloxane resin and bisacylphosphine oxide photoinitiator.

[0002] UV or LED initiated polymerization curing is desirable for high throughput processing. Curing is induced by a photoinitiator that is compatible with the polymer; however, for organopolysiloxane curing systems, compatibility is a long-standing and hitherto unsolved problem. Photoinitiators that are poorly compatible as curing agents are undesirable because they will separate from the silicone matrix during storage, resulting in 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 -CH2-0-Si(OR)3 group, a typical example of which is the following compound:

[0004]

[0005] While Tan discloses that these photoinitiators solve the long-standing solubility problem, it is apparent that another problem is introduced, namely the susceptibility of the silyl ether bond (CH2-OSi) to acid cleavage, which thereby renders the photoinitiator incompatible with the silicone matrix. It would therefore be advantageous to achieve solubility as well as to maintain stability in the field of photoinitiating silicone systems. SUMMARY

[0006] The present invention solves the needs of the art by providing a composition comprising a bisacylphosphine oxide photoinitiator and a polyacrylate functionalized organosiloxane; wherein the bisacylphosphine oxide photoinitiator is a compound of Formula 1:

[0007]

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

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

[0010] each R 2 is independently C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R 2 and adjacent R 2together a 1,3-dioxolane group or a 1,4-dioxane group;

[0011] each R 3 independently C1-C6-alkyl or C1-C6-alkoxy;

[0012] R 4 is

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

[0014] p is 0 or 1, with the proviso that when p is 0, q is 3 to 12, and when p is 1, q is 2 to 12;

[0015] r is 3 to 300;

[0016] X is CH2CH2or CH(CH3);

[0017] s is 0 or 1, with the proviso 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] wherein the dotted line is the point of attachment from Y to X; and

[0020] each R 5 independently C1-C6-alkyl or phenyl;

[0021] or R 4 is

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

[0023] p is 0 or 1, with the proviso that when p is 0, t is 4, and when p is 1, t is 2; and

[0024] Z is:

[0025]

[0026] wherein the dotted line is the point of attachment from Z to (CH2) t .

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

[0028] The present invention is a composition comprising a composition comprising a bisacyl phosphine oxide photoinitiator and a polyacrylate functionalized organosiloxane; wherein the bisacyl phosphine oxide photoinitiator is a compound of Formula 1:

[0029]

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

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

[0032] each R 2 is independently C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R 2 and an adjacent R 2 on the phenyl ring together is a 1,3-dioxolane group or a 1,4-dioxane group;

[0033] each R 3 is independently C1-C6-alkyl or C1-C6-alkoxy;

[0034] R 4 is

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

[0036] p is 0 or 1, with the proviso that when p is 0, q is 3 to 12, and when p is 1, q is 2 to 12;

[0037] r is 3 to 300;

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

[0039] s is 0 or 1, with the proviso 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] wherein the dotted line is the point of attachment from Y to X; and

[0042] each R 5 is independently C1-C6-alkyl or phenyl;

[0043] or R 4 is

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

[0045] p is 0 or 1, with the proviso that when p is 0, t is 4, and when p is 1, t is 2; and

[0046] Z is:

[0047]

[0048] wherein the dotted line is the point of attachment from Z to (CH2) t .

[0049] In one aspect, R 1 is -C(O)-phenyl-(R 2 ) m . Examples of preferred R 1 groups are represented by the following structures:

[0050]

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

[0052] Compounds of Formula I can be prepared as described in Schemes 1 to 3. In R1 -C(O)-phenyl-(R 2 ) m and R 4 located in the para position of the phenyl ring, can be prepared according to Scheme 1. The reaction conditions for each step are described in the experimental section.

[0053] Scheme 1

[0054]

[0055] wherein q’ is 1 to 10 when p is 0 and 0 to 10 when p is 1.

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

[0057]

[0058] wherein X is CH2CH2or CH(CH3).

[0059] In the case where p is 1, the first compound in Scheme 1 can be prepared by contacting dibromobenzene (in particular, p-dibromobenzene) with vinyl dimethylsilyl chloride in the presence of n-butyllithium in the first step to form the following intermediate:

[0060]

[0061] wherein b is 0 to 10.

[0062] In the case where p is 0, the first compound (in particular, in the case where q’ is 2) can be prepared as described in Li, Y.-L.; Song, D.-P.; Pan, L.; Ma, Z.; Li, Y.-S. Polym. Chem. 2019, 10, 6368-6378.

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

[0064] Scheme 2

[0065]

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

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

[0068] Scheme 3

[0069]

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

[0071]

[0072] wherein q’ is 1 to 10 when p is 0 and 0 to 10 when p is 1.

[0073] As used herein, the term “polyacrylate-functionalized organosiloxane” refers to an organosiloxane functionalized with two or more acrylate or methacrylate groups, which groups are spaced apart from the silicon atoms by divalent hydrocarbyl groups, preferably -CH2- or -CH2CH2CH2- groups. An example of a fragment of a polyacrylate-functionalized organosiloxane is shown in formula 2:

[0074]

[0075] wherein R 6 is H or methyl; e is 1 or 3; and the dashed line indicates attachment of the fragment to an M unit, a D unit, a T unit, or a Q unit; and c is 1 to 4.

[0076]

[0077] wherein R 7 is C1-C6 alkyl, preferably methyl; and each R 8 is C1-C6-alkyl, preferably methyl or phenyl.

[0078] In the case where moisture cure is desired, the acrylate-functionalized organosiloxane advantageously further comprises C1-C6-alkoxysilyl groups, preferably two or more methoxysilyl groups. An example of this sub-class of bifunctionalized polymers is shown in formula 3:

[0079]

[0080] wherein d is in the range of 1 to 5000. Alternatively, the composition can also comprise an organopolysiloxane functionalized with a C1-C6-alkoxysilyl group, preferably two or more methoxysilyl groups.

[0081] In case of moisture cure is required, the composition advantageously comprises a moisture cure catalyst, such as a titanium catalyst, and an example thereof is titanium dioxide acetylacetate complex, commercially available as Tyzor PITA-SM organotitanate.

[0082] The composition of the present application is capable of UV curing as well as moisture curing in case of comprising a single compound having both Si-alkenyl / Si-alkoxy functionality or a mixture of compounds having Si-alkenyl and Si-alkoxy functionality.

[0083] Example

[0084] Intermediate Example 1 - Preparation of M'D 14 M' polysiloxane substituted photoinitiators

[0085] A. Preparation of (4-(but-3-en-1-yl)phenyl)dichlorophosphine

[0086] In a glove box, a 500 mL round bottom flask was charged with 1-bromo-4-(but-3- en-1-yl)benzene (17.1 g), anhydrous THF (118 mL), and anhydrous diethyl ether (37 mL). The flask was sealed and transferred to a fume hood. The mixture was stirred under N2and cooled to -78 °C, then n-butyllithium (n-BuLi, 2.5 M in hexanes, 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 warm to ambient temperature. The solution was poured into a separatory funnel containing diethyl ether and water. The phases were separated, and the aqueous phase was extracted with several portions of diethyl ether. The combined organic fractions were washed with brine, dried over MgS04, and concentrated in vacuo.

[0087] The crude oil was transferred to a 1000-mL round bottom flask, which was placed in a glove box. The oil was dissolved in anhydrous diethyl ether (100 mL). The mixture was stirred and treated dropwise with HC1 (2.0 M in diethyl ether, 162 mL, 324 mmol, 4.00 equiv), and a white solid precipitated. After 2 hours, the slurry was filtered, and the filtrate was concentrated. A colorless oil was isolated (15.9 g, 84%), which was used in the next step without further purification.

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

[0089] In a glovebox, a 500 mL jar was charged with diethyl ether (100 mL) and LiAlH4(2.0 M in THF, 19.8 mL, 39.6 mmol, 0.60 equiv). The solution was stirred vigorously and (4-(but-3-en-1-yl)phenyl)dichlorophosphine (15.4 g, 66.1 mmol, 1.00 equiv) in diethyl ether (65 mL) was added dropwise to the solution over 10 minutes. The mixture was stirred for 30 minutes before solid sodium dichromate (25.5 g, 79.3 mmol, 1.20 equiv) was carefully added. The mixture was stirred for 60 minutes and the liquid was decanted and filtered through a 0.45 pm syringe filter and concentrated to give a colorless oil (9.73 g, 90%) which was used in the next step without further purification.

[0090] C. Preparation of ((4-(but-3-en-1-yl)phenyl)phosphoryl)bis(mesitylphenone)

[0091] In a glovebox, a solution of the preparation of (4-(but-3-en-1-yl)phenyl)phosphine (9.73 g, 59.3 mmol, 1.00 equiv) in anhydrous THF (300 mL) was treated with sodium tert-butoxide (Nat-OBu, 11.4 g, 118 mmol, 2.00 equiv) and 2,4,6-trimethylbenzoyl chloride (19.8 mL, 118 mmol, 2.00 equiv) was added dropwise to the mixture. The mixture was stirred overnight. The crude 31 P NMR spectroscopic analysis indicated that the phosphine was partially consumed. An additional amount of Nat-OBu (3.99 g) and benzoyl chloride (6.9 mL) was added to the reaction mixture. After 5 hours, the mixture was filtered to remove sodium chloride and the filtrate was removed from the glovebox and concentrated in vacuo. The crude residue was dissolved in dichloromethane (200 mL) and the solution was treated with hydrogen peroxide (6.0 mL, 30 wt%) and stirred overnight at ambient temperature before being treated with aqueous sodium bisulfite (100 mL) and stirred until the organic phase was negative for peroxide strip test. The phases were separated and concentrated with celite for silica gel chromatography (0% to 50% EtOAc / hexanes). A yellow oil (13 g) containing the product and some other impurities was isolated. A second column purification was performed whereby intermediate Example 3 was isolated as a yellow oil (11.3 g).

[0092] D. Preparation of M'D 14 M' polysiloxane substituted photoinitiators

[0093] A preparation of ((4-(but-3-en-1-yl)phenyl)phosphoryl)bis(mesityl ketone) (0.07 g) was treated with anhydrous hexanes (3.0 mL) and M'D 14M' polysiloxane (0.99 g) was mixed in a glove box. The mixture was stirred at 50 °C until the solids dissolved. Karstedt's Catalyst (2 wt% Pt in xylene, 0.03 mL) was added and the mixture was stirred overnight. The consumption of olefin was monitored by 1 H NMR spectroscopy and additional portions of Karstedt's Catalyst were added until < 5% of the olefin remained. Vinyltrimethoxysilane was added to react with the remaining Si-H groups.

[0094] The volatiles were removed by a vacuum pump, leaving an amber oil. The mixture of products was determined and calculated to contain 4.0 wt% photoinitiator.

[0095]

[0096] Intermediate Example 2 - Preparation of M'D 14 M' polysiloxane substituted photoinitiators

[0097] A. Preparation of (4-bromophenyl)dimethyl(vinyl)silane

[0098] A 1000-mL 3 -neck round bottom flask, fitted with an additional funnel, was charged with anhydrous THF (425 mL) and 1,4-dibromobenzene (20.0 g, 84.8 mmol, 1.00 equiv) under N2blanket. The mixture was stirred and cooled to -78 °C. An n-BuLi solution (2.5 M in hexanes, 35.6 mL, 89.0 mmol, 1.05 equiv) was added dropwise to the dibromobenzene solution over 25 minutes. After the n-BuLi solution addition was complete, stirring was continued for an additional 50 minutes.

[0099] Chlorodimethylvinylsilane (12.9 mL, 93.3 mmol, 1.10 equiv) was added dropwise to the reaction mixture with stirring. The mixture was gradually warmed to room temperature over 1 hour, after which the mixture was quenched with aqueous ammonium chloride. The product was extracted with several portions of ethyl acetate. The combined organic fractions were dried over sodium sulfate and concentrated. The crude oil was purified in vacuo (450 mTorr, 52 °C - 60 °C) to give (4-bromophenyl)dimethyl(vinyl)silane (18.75 g) as a colorless oil.

[0100] B. Preparation of ((4-(dimethyl(vinyl)silyl)phenyl)phosphoryl)bis(mesitylphenone)

[0101] In a glove box, a 250-mL round bottom flask was charged with (4-bromophenyl)dimethyl(vinyl)silane (4.31 g, 17.9 mmol, 1.00 equiv), anhydrous THF (26 mL), and anhydrous diethyl ether (8 mL). The flask was sealed and transferred to the fume hood. The mixture was stirred under nitrogen and cooled to -78 °C. At this point, n-BuLi (2.5 M in hexanes, 7.51 mL, 18.8 mmol, 1.05 equiv) was added dropwise. The mixture was stirred for 30 minutes before adding chlorobis(diisopropylamino)phosphine as a solid (5.01 g, 18.8 mmol, 1.05 equiv). The mixture was stirred and allowed to warm to ambient temperature over 2 hours. The solution was poured into a separatory funnel containing diethyl ether and water. The phases were separated, and the aqueous phase was extracted with several portions of diethyl ether. The combined organic fractions were washed with brine, dried over MgS04, and concentrated by rotary evaporation.

[0102] The crude oil was transferred to a 250-mL round bottom flask, which was placed in a glove box. The oil was dissolved in anhydrous diethyl ether (20 mL). The flask was sealed and transferred to the fume hood. The mixture was stirred under N2and cooled to 0 °C. Then HCl (2.0 M in diethyl ether, 35.7 mL, 71.5 mmol, 4.00 equiv) was added dropwise, and a white solid precipitated. After stirring for 2 hours, the slurry was filtered, and the filtrate was concentrated. The crude residue was mixed with diethyl ether and hexanes and filtered again. The filtrate was concentrated to give a colorless oil (4.59 g). The crude material was used in the next step without further purification.

[0103] In a glove box, a 150-mL jar was charged with diethyl ether (44 mL) and LiAlH4(2.0 M in THF, 5.23 mL, 10.5 mmol, 0.60 equiv) with vigorous stirring. The crude material from the previous step (4.59 g, 17.4 mmol, 1.00 equiv) was added dropwise to the LiAlH4solution over 5 minutes. The mixture was stirred for 30 minutes before adding solid sodium sulfate (6.74 g, 20.9 mmol, 1.20 equiv) carefully. Stirring was continued for 14 hours before 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.

[0104] A solution of the crude material from the previous step (2.71 g) in anhydrous THF (70 mL) was treated with anhydrous Nat-OBu (2.68 g, 27.9 mmol, 2.00 equiv), followed by the dropwise addition of 2,4,6-trimethylbenzoyl chloride (4.65 mL, 27.9 mmol, 2.00 equiv). The mixture was stirred for 3 hours, and then the mixture was filtered to remove sodium chloride.

[0105] The filtrate was removed from the glovebox and concentrated in vacuo. The crude residue was dissolved in dichloromethane (50 mL) and the solution treated with hydrogen peroxide (1.4 mL, 30 wt%). The mixture was stirred at ambient temperature overnight, then treated with aqueous sodium bisulfite (30 mL). The phases were separated and the organic phase concentrated in the presence of silica gel to facilitate silica gel liquid chromatography (0% to 50% EtOAc / hexanes). ((4-(dimethyl(vinyl)silyl)phenyl) phosphoryl)bis(mesityl ketone) was isolated as a yellow oil (1.98 g) which solidified upon standing.

[0106] C. Preparation of M'D 14 M' polysiloxane substituted photoinitiators

[0107] ((4-(dimethyl(vinyl)silyl)phenyl) phosphoryl)bis(mesityl ketone) (0.10 g) was mixed with anhydrous toluene (1.5 mL) and M'D 14 M' polysiloxane (0.24 g) was mixed in a glovebox. The mixture was stirred at 80 °C until the solid dissolved. To the mixture was added Karstedt's catalyst (2 wt% Pt in xylene, 0.012 mL) and stirring was continued for 1 hour. The consumption of olefin was monitored by H NMR spectroscopy and additional portions of Karstedt's catalyst were added until <5% of the olefin remained. Vinyltrimethoxysilane was added to react with the remaining Si-H groups. Volatiles were removed in vacuo, leaving an amber oil. The mixture of products was identified and calculated to contain 30.0 wt% photoinitiator. 1 The consumption of olefin was monitored by H NMR spectroscopy and additional portions of Karstedt's catalyst were added until <5% of the olefin remained. Vinyltrimethoxysilane was added to react with the remaining Si-H groups. Volatiles were removed in vacuo, leaving an amber oil. The mixture of products was identified and calculated to contain 30.0 wt% photoinitiator.

[0108]

[0109] Example 1 - Preparation of a dual curable organopolysiloxane composition

[0110] An UV-curable organopolysiloxane composition was prepared by blending the compound of Formula 3 (10 pbw, d = 120) with the bisacylphosphine oxide photoinitiator of Intermediate Example 1 or 2 (0.1 pbw). The blend was mixed at 1000 rpm for 20 seconds, then at 2000 rpm for 45 seconds. The sample was then packaged in three 30-mL syringes and degassed, then vacuum-sealed in an aluminum bag to avoid moisture and light.

[0111] Comparative Example 1 - Preparation of a dual curable organopolysiloxane composition

[0112] 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 (0.1 pbw, Irgacure 819) was used.

[0113] LED curing procedure

[0114] The samples were cured using a Uvitron Skyray 800 LED flood cure system with 365-nm LEDs at an intensity of 500 mW / cm 2 and an irradiance dose of 10 J / cm 2 .

[0115] LED cure depth measurement

[0116] The formulations were filled into a Teflon block having a hole with a diameter of 25 mm and a depth of 20 mm. The coating was exposed to LED irradiation. The sample was removed from the hole and the uncured material was removed with a paper towel so that the depth of cure could be measured with a ruler.

[0117] Table 1 illustrates the formulation appearance, coating appearance, and depth of cure for samples cured by LED irradiation. A depth of cure of > 3 mm was considered acceptable.

[0118]

[0119] The data show that compositions containing the photoinitiator of the present application produce uniform formulations and coatings and acceptable depths of cure for LED irradiation. In contrast, compositions containing the Irgacure 819 photoinitiator are non-uniform and produce non-uniform coatings.

Claims

1. A composition comprising a bisacyl phosphine oxide photoinitiator and a polyacrylate-functionalized organosiloxane; wherein the bisacyl phosphine oxide photoinitiator is a compound of Formula 1: Formula 1 wherein m is 0, 1, 2, or 3; and n is 0, 1, or 2; 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 1 is -phenyl-(R 3 ) n , -C(O)-phenyl-(R 2 ) m , -O-C1-C 20 -alkyl or -O(CH2CH2O) x -H, wherein x is 1 to 20; each R is independently C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R 2 is independently C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R 2 with the adjacent R 2 together on the phenyl ring is 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 To i) -(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y; wherein r is 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 wherein the dashed line is the point of attachment from Y to X; and ； p is 0 or 1, provided that when p is 0, t is 4, and when p is 1, t is 2; and Each R 5 Independently, it is a C1-C6-alkyl or phenyl group; or R 4 is ii) -(Si(Me2))2-; and p (CH2) t -Z; wherein Z is:

2. The composition of claim 1, wherein the polyacrylate-functionalized organosiloxane comprises a fragment represented by Formula 2: Formula 2 wherein the dashed line is the point of attachment from to the CH2CH2 group. wherein the dotted line is the point of attachment from Z to (CH2) t .

5. The composition of any one of claims 1 to 4, wherein the polyacrylate-functionalized organosiloxane is further functionalized with at least two C1-C6-alkoxysilyl groups. wherein e is 1 or 3; R 6 is H or methyl; and the dotted line indicates the attachment of the fragment to a silicon atom attached to a M unit or a D unit or a T unit or a Q unit; and c is 1 to 4.

3. The composition of claim 2, wherein z is 1; R 1 is -C(O)-phenyl-(R 2 ) m ; each R 2 is methyl, each m is 3, each n is 0, and R 4 is -(Si(Me2)) p (CH2) q (Si(R 5 2)O) r (X) s -Y, wherein each R 5 is methyl, X is CH2CH2, r is 10 to 200; q is 3 when p is 0 and q is 2 when p is 1; and Y is Si(OMe)3 or 6. The composition of claim 5, wherein the polyacrylate-functionalized organosiloxane is represented by the following formula: Formula 3 wherein d is 1 to 5000.

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

7. The composition of any one of claims 1 to 4, further comprising an organopolysiloxane functionalized with at least two C1-C6-alkoxysilyl groups.

8. The composition of claim 1, wherein the bisacyl phosphine oxide photoinitiator is selected from the group consisting of: wherein r is 6 to 50.

9. The composition of claim 1, wherein the bisacyl phosphine oxide photoinitiator is selected from the group consisting of: wherein r is 6 to 50. a) applying the composition of any one of claims 1 to 9 to a substrate; then b) curing the composition by UV or LED curing.

10. A method of making a cured composition, the method comprising: a) applying the composition of any one of claims 1 to 9 to a substrate; then b) curing the composition by UV or LED curing.

10. A method comprising the steps of: ​ ​

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