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EP-4504741-B1 - ACYLPHOSPHINE OXIDE PHOTOINITIATOR

EP4504741B1EP 4504741 B1EP4504741 B1EP 4504741B1EP-4504741-B1

Inventors

  • GRIGG, Robert David
  • REDDEL, Jordan C.
  • AXTELL, Jonathan
  • MUKHOPADHYAY, Sukrit
  • BISWAS, Souvagya
  • LIU, JUNYING

Dates

Publication Date
20260506
Application Date
20230330

Claims (9)

  1. A compound represented by Formula I: R 1 is -phenyl-(R 3 ) m , -C(O)-phenyl-(R 2 ) m , -O-C 1 -C 20 -alkyl, or -O(CH 2 CH 2 O) x -H, each R 2 is independently C 1 -C 6 -alkyl; C 1 -C 6 -alkoxy; -OCH 2 -phenyl; or R 2 together with an adjacent R 2 on the phenyl ring a 1,3-dioxolane group or a 1,4-dioxane group; each R 3 is independently C 1 -C 6 -alkyl or C 1 -C 6 -alkoxy; each m is independently 0, 1, 2, or 3; n is 0, 1 or 2; p is 0 or 1 with the proviso that when p is 0, q' is 1 to 10, and when p is 1, q' is 0 to 10; and x is from 1 to 20.
  2. The compound of Formula I wherein R 1 is -C(O)-phenyl-(R 2 ) m , n is 0, p is 1, and q' is 2.
  3. The compound of Claim 2 where m is 3, each R 2 is methyl, and R 1 is represented by the following fragment:
  4. The compound of Claim 1 wherein R 1 is -O-C 1 -C 20 -alkyl, or -O(CH 2 CH 2 O) x -H; n is 0, p is 1, q' is 2; each R 2 is methyl, and R 1 is represented by the following fragment:
  5. The compound of Claim 1 wherein R 1 is -phenyl-(R 3 ) m ; n is 0, p is 1, q' is 2; each R 2 is methyl, and R 1 is represented by the following fragment:
  6. A process for preparing a siloxane functionalized photoinitiator comprising the step of contacting under reactive conditions and in the presence of a platinum-containing catalyst the compound of Formula I of Claim 1 with a hydrosilane selected from the group consisting of: and where r is from 3 to 300, and each R 5 is independently C 1 -C 6 -alkyl or phenyl and where X is CH 2 CH 2 or CH(CH 3 ).
  7. The process of Claim 6 where the hydrosilane is and the process further includes the step of contacting in the presence of a platinum-containing catalyst the product of the reaction of the compound of Formula I and the hydrosilane with a compound of the following formula: to form a compound having the following formula: where Y is Si(OMe) 3 ; SiMe 3 ; Si(OEt) 3 ; SiMe 2 OMe; SiMe 2 OEt; Si(OSiMe 3 ) 3 ; SiMe(OSiMe 3 ) 2 ; or SiMe 2 (OSiMe 3 ).
  8. The process of Claim 7 where r is from 6 to 50 and Y is Si(OMe) 3 .
  9. The process of Claim 6 where the hydrosilane is either or where X is CH 2 CH 2 or CH(CH 3 ).

Description

Background of the Invention The present invention relates to an acylphosphine oxide photoinitiator that useful as an intermediate for an organpolysiloxane compatible photoinitiator. A continuing challenge in the field of organopolysiloxane curing systems is designing a photoinitiator that is compatible with the organopolysiloxane. Photoinitiators with poor compatibility are undesirable as curing agents because they separate from the silicone matrix during storage, resulting in severe haze of the cure product. US 10,597,413 B2 (Tan) describes an acyl phospine oxide substituted with -CH2-O-Si(OR)3 groups, a typical example of which is the following compound: Although Tan discloses that these photoinitiators address a long-standing solubility problem, it is evident that another problem is introduced, namely susceptibility to acid cleavage of the silyl ether bond (CH2-OSi), thereby rendering the photoinitiator incompatible with the silicone matrix. EP1749513 relates to polymerizable dental material containing at least one radically polymerizable monomer and at least one bisacylphosphine oxide. CN105837731 discloses a macromolecular photoinitiator having the structure: where m is 50 to 500 and n is 50 to 500. It would therefore be an advantage in the art of photoinitiation in silicone systems to achieve solubility and with maintenance of stability. Summary of the Invention The present invention addresses a need in the art by providing, in a first aspect, a compound represented by Formula I: R1 is -phenyl-(R3)m, -C(O)-phenyl-(R2)m, -O-C1-C20-alkyl, or -O(CH2CH2O)x-H,each R2 is independently C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R2 together with an adjacent R2 on the phenyl ring a 1,3-dioxolane group or a 1,4-dioxane group;each R3 is independently C1-C6-alkyl or C1-C6-alkoxy;each m is independently 0, 1, 2, or 3; n is 0, 1 or 2; p is 0 or 1 with the proviso that when p is 0, q' is 1 to 10, and when p is 1, q' is 0 to 10; and x is from 1 to 20. In another aspect, the present invention is a process for preparing a siloxane functionalized photoinitiator comprising the step of contacting under reactive conditions and in the presence of a platinum-containing catalyst the compound of Formula I with a hydrosilane selected from the group consisting of: and where r is from 3 to 300 and where X is CH2CH2 or CH(CH3). The compound of the present invention is useful as an intermediate for an organpolysiloxane compatible photoinitiator. Detailed Description of the Invention In a first aspect, the present invention is a compound represented by Formula I: R1 is -phenyl-(R3)m, -C(O)-phenyl-(R2)m, -O-C1-C20-alkyl, or -O(CH2CH2O)x-H,each R2 is independently C1-C6-alkyl; C1-C6-alkoxy; -OCH2-phenyl; or R2 together with an adjacent R2 on the phenyl ring a 1,3-dioxolane group or a 1,4-dioxane group;each R3 is independently C1-C6-alkyl or C1-C6-alkoxy;each m is independently 0, 1, 2, or 3; n is 0, 1 or 2; p is 0 or 1 with the proviso that when p is 0, q' is 1 to 10, and when p is 1, q' is 0 to 10; and x is from 1 to 20. In one aspect, R1 is -C(O)-phenyl-(R2)m. An example of a preferred R1 group is represented by the following structure: In one aspect, when p is 0, q is 3 or 4; in another aspect, when p is 1, q is 2; r is from 3 or from 6 or from 10, to 300 or to 200 or to 100 or to 50. The compound of Formula I can be prepared as described in Schemes 1 to 3. Where R1 is -C(O)-phenyl-(R2)m, the compound of Formula I (Ia) can be prepared in accordance with Scheme 1. The reaction conditions for each step are described in the experimental section. where q' is 1 to 10 when p is 0, and q' is 0 to 10 when p is 1. Where p is 1, the first compound in Scheme 1 can be prepared by contacting in a first step a dibromobenzene, particularly p-dibromobenzene, with a vinyl dimethylsilyl chloride in the presence of n-butyl lithium to form the following intermediate A'. Where p is 0, the first compound, especially 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. A photoinitiator that is compatible with an organopolysiloxane solvent can be prepared by reacting, in the presence of a Pt containing catalyst, the compound of Formula I with a compound of the following formula:         H-Si(R52)O[Si(R52)O]r-Si(R52)-H where r is from 3 or from 6, to 300 or to 200 or to 100 or to 50, and each R5 is independently C1-C6-alkyl or phenyl. This compatibilized photoinitiator is advantageously further reacted with a compound having the formula: where Y is Si(OMe)3; SiMe3; Si(OEt)3; SiMe2OMe; SiMe2OEt; Si(OSiMe3)3; SiMe(OSiMe3)2; or SiMe2(OSiMe3). A compatible photoinitiator may also be prepared by reacting, in the presence of a Pt containing catalyst, the compound of Formula I with a compound of either Compound A or Compound B: where X is CH2CH2 or CH(CH3). The reaction is typically carried out in a non-polar aprotic solvent such as hexane or xylene, and at advanced temper