US 20040186 195A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2004/0186195A1 Suzuki et al. (43) Pub. Date: Sep. 23, 2004 (54) PHOTOPOLYMERIZATION INITIATOR AND Publication Classification PHOTOPOLYMERIZABLE COMPOSITION (51) Int. Cl." ................................. C08F 2/46; CO8J 3/28 (76) Inventors: Takeshi Suzuki, Tokyo (JP); Hideki (52) U.S. Cl. ................................................................ 522/31 Kazama, Tokyo (JP) (57) ABSTRACT Correspondence Address: Leonard W. Sherman A photopolymerization initiator comprising (A) a photo Sherman & Shalloway acid-generating compound Such as diaryliodonium salt (e.g., 413 N. Washington Street diphenyl iodonium, bis(p-chlorophenyl)iodonium, etc.), (B) Alexandria, VA 22314 (US) a photo oxidation radical-generating compound Such as (21) Appl. No.: 10/737,827 diarylketone compound, C-diketone compound or ketocou marin compound, and (C) a fused polycyclic aromatic (22) Filed: Dec. 18, 2003 compound Such as 1,4-dimethylnaphthalene, 1-methylan thracene, 9-methylanthracene, 9,10-dimethylanthracene or (30) Foreign Application Priority Data 9,10-diethylanthracene. The photopolymerization initiator makes it possible to efficiently polymerize the cationically Dec. 18, 2002 (JP)...................................... 2002-36708O polymerizable monomer by the irradiation with visible light. US 2004/0186195 A1 Sep. 23, 2004 PHOTOPOLYMERIZATION INITIATOR AND monomers that are not impaired for their polymerization by PHOTOPOLYMERIZABLE COMPOSITION oxygen and that undergo little Volumetric shrinkage upon the polymerization. However, the photo-radical polymeriza FIELD OF THE INVENTION tion initiatorS Such as an O-diketone and an acylphosphine 0001. The present invention relates to a photopolymer oxide compound, that are usually used for the dental appli ization initiator capable of efficiently polymerizing both a cations, are not capable of polymerizing the cationically cationically polymerizable monomer and a radically poly polymerizable monomers. Therefore, a photo-cationic poly merizable monomer, and to a photopolymerizable compo merization initiator is necessary. Sition containing the above photopolymerization initiator. 0006. As the photo-cationic polymerization initiators, More particularly, the invention relates to a photopolymer there have been known photo acid-generating compounds izable composition that can be favorably used as the dental Such as an iodonium Salt type compounds and Sulfonium Salt materials. type compounds. However, these photo acid-generating compounds do not, usually, absorb light in the visible to near DESCRIPTION OF THE RELATED ART ultraViolet regions, and cannot excite the polymerization reaction to a Sufficient degree even by using a Source of 0002 To restore a tooth that is damaged due to caries or Visible light that is used for the dental applications, e.g., even breakage, there is usually used a photocurable filling restor by using a source of light such as a halogen lamp (370 to 550 ative called composite resin owing to its easy use and high nm). In order to obtain a Sufficient degree of polymerization aesthetic appearance. The above composite resin usually activity even by the irradiation with light in the visible light comprises a polymerizable monomer, a filler and a poly region, therefore, there has been proposed to blend a photo merization initiator. AS the polymerizable monomer, there has been used a (meth)acrylate type radically polymerizable acid-generating compound with additives. monomer from the Standpoint of its good photopolymeriZ 0007 For example, there has been proposed to use a able property. photo acid-generating agent in combination with a polycy 0003. However, the radically polymerizable monomer is clic aromatic compound Such as an anthracene or an impaired for its polymerization due to oxygen. When poly anthracene derivative having an alkoxy group or an acyloxy merized and cured in an oral cavity, therefore, an unpoly group (documents 1 to 9). merized layer or a layer of a low polymerization degree 0008 Document 1: A. Yamaoka, G., Matsunaga, “Pho remains on the Surface thereof acquiring color or changing topolymer Technology', Nikkan-Kogyo Shimbunsha color with the passage of time making it difficult to obtain Co., pp. 38-46 aesthetic appearance to a Sufficient degree. By using the 0009 Document 2: The Society of Polymer Science, conventional dental composite resins using the radically Japan, “Synthesis and Reaction of polymer (1), Syn polymerizable monomer, therefore, the Surfaces thereof thesis of addition polymerized polymer, KyoritSu must be sufficiently polished after it is polymerized and Shuppansha Co., pp. 400-404 cured in the oral cavity So that good aesthetic appearance is fully exhibited. 0010) Document 3: K. Morio, H. Tsuchiya, T. Endo, 0004 Besides, the (meth)acrylate type radically polymer “Modern Progress in the Photo-Initiated Cationic Poly izable monomer has a problem of large Volumetric Shrinkage merization', Functional Material, CMC Co., October, due to polymerization. Namely, a cavity in the tooth that 1985, pp. 5-13 must be restored is filled with a restorative Such as a 0011 Document 4: Japanese Unexamined Patent Pub composite resin which is, then, polymerized and cured by lication (Kokai) No. 8-20728 being irradiated with light through the Surface of the restor 0012 Document 5: Japanese Unexamined Patent Pub ative that is filled. Due to volumetric shrinkage by polymer lication (Kokai) No. 10-147608 ization, however, there is produced a StreSS in a direction to float on the interface of the tooth creating a gap between the 0013 Document 6: Japanese Unexamined Patent Pub tooth and the restorative. To cope with the shrinking StreSS lication (Kokai) No. 11-199681 due to polymerization, therefore, there have been proposed 0014) Document 7: Japanese Unexamined Patent Pub a variety of dental adhesives that produce very Strong lication (Kokai) No. 2000-7716 adhering forces. However, the State of tooth varies depend ing upon the individuals or depending upon the teeth even in 0015 Document 8: Japanese Unexamined Patent Pub the same perSon. Even by using the above dental adhesives, lication (Kokai) No.2001-81290 therefore, a perfect adhesion is not necessarily accomplished 0016 Document 9: Japanese Unexamined Patent Pub for-all teeth. Therefore, it has been urged to provide a dental lication (Kokai) No. 11-322952 composite resin which undergoes the Volumetric Shrinkage 0017. The photopolymerizable compositions blended due to the polymerization as little as possible and which does with the fused polycyclic aromatic compounds disclosed in not develop gap that results from the Volumetric Shrinkage the above documents are Surely improved for their polymer due to the polymerization. To accomplish a high adhering ization property upon the irradiation with visible light as force, further, the above dental adhesives require complex compared to when they are not blended with the above technique causing an increase in the cost. Therefore, it has compounds. However, they are polymerized at a Small rate further been desired to Simplify the Steps of adhering opera and are not still Satisfactory as dental polymerization initia tion. tors which must be cured within short periods of time in the 0005 There has also been known cationically polymer oral cavity and are not satisfactory, either, from the Stand izable monomerS Such as an epoxide as polymerizable point of depth of curing. US 2004/0186195 A1 Sep. 23, 2004 0.018. There has further been proposed to use a photo cally polymerizable monomers, therefore, it is necessary to acid-generating compound in combination with a photo blend the radical polymerization initiator. Use of the cationic radical generator Such as camphor quinone (documents 10 to polymerization initiator and the radical polymerization ini 12). tiator in combination, however, requires cumberSome con 0019) Document 10: International Patent Publication trol work at the time of production, and is not desirable. No. 10-508067 SUMMARY OF THE INVENTION 0020) Document 11: Japanese Unexamined Patent 0027. It is, therefore, an object of the present invention to Publication (Kokai) No. 11-130945 provide a photopolymerization initiator which makes it 0021 Document 12: International Patent Publication possible to obtain a photopolymerizable composition that No. 2001-520758) can be cured Sufficiently deeply and at a Sufficiently high rate by the irradiation with visible light that is widely used in the 0022. When the photo-radical generator is used in com field of dental applications, and is particularly Suited for the bination with the photo acid-generating compound as dental applications. described above, the polymerization is improved without, however, accompanied by a polymerization rate that is high 0028. Another object of the present invention is to pro enough for dental applications. vide a photopolymerization initiator capable of efficiently 0023 There has further been proposed a cationic poly polymerizing not only the cationically polymerizable mono merization initiator obtained by blending a photo acid mers but also the radically polymerizable monomers. generating compound with an anthracene derivative having 0029. A further object of the present invention is to an alkoxy group and with a thioxanthone derivative (docu provide a photopolymerizable composition containing the ment 13). above photo-cationic polymerization initiator. 0024 Document 13: Japanese Unexamined Patent 0030 The