Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
1999-11-30
2003-03-18
Buttner, David J. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C528S378000, C528S380000
Reexamination Certificate
active
06534589
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing optical materials such as plastic lenses, prisms, optical fibers, information recording substrates and filters, and more particularly, to a process for producing plastic lenses of glasses.
2. Description of the Related Arts
Plastic materials have widely been used for various optical materials, particularly as lenses of glasses, ecaus 1 eight, toughness and easiness of tinting. The properties required for optical materials, particularly for lenses of glasses, are a low specific gravity, excellent transparency, suppressed yellow color and optical properties which are a large refractive index and a large Abbe number. A large refractive index is important to decrease the thickness of a lens. A large Abbe number is important to decrease chromatic aberration of a lens. The present inventors have discovered novel episulfide compounds which can provide optical materials having a small thickness and a small chromatic aberration, i.e., a refractive index of 1.7 or larger and an Abbe number of 35 or larger, as disclosed in the specifications of Japanese Patent Application Laid-Open Nos. Heisei 9(1997)-71580, Heisei 9(1997)-110979 and Heisei 9(1997)-255781. The optical materials obtained in accordance with these inventions can provide sufficient quality in appearance when the optical materials are used for ordinary plastic lenses. However, plastic lenses may be used in very hot conditions or exposed to light for a very long time. Therefore, it is desired that optical materials have more improved properties such as more improved oxidation resistance and light resistance. Moreover, it is almost needless to mention that a resin having more colorless and transparent appearance is preferable when the resin is used as an optical materials such as a material for optical lenses.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above problems and to provide a process for producing a resin having a large refractive index which exhibits more improved light resistance, oxidation resistance, transparency and color tone than those achieved in accordance with conventional technologies using an episulfide compound having an epithio structure represented by formula (1) or a composition comprising the episulfide compound as the material.
(R
1
represents a hydrocarbon group having 1 to 10 carbon atoms, R
2
, R
3
and R
4
each represents hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, Y represents S, O, Se or Te and m and n each represents 0 or 1.)
As the result of intensive studies by the present inventors to produce a resin having a large refractive index which exhibits excellent light resistance, oxidation resistance, transparency and color tone from an episulfide compound having epithio structures represented by formula (1) or a composition comprising the episulfide compound, it was found that a resin having a large refractive index which exhibits excellent light resistance and oxidation resistance can be obtained by curing an episulfide compound having epithio structures represented by formula (1) or a composition comprising the episulfide compound by polymerization in the presence of a phenol derivative. It was also found that a resin having a large refractive index which exhibits excellent light resistance and oxidation resistance can be obtained by using at least one polymerization catalyst selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salt and secondary iodonium salts as the polymerization catalyst. The present invention has been completed on the basis of the above knowledge.
The present invention provides:
A process for producing a resin having a large refractive index which comprises curing an episulfide compound having one or more epithio structures represented by formula (1) in one molecule or a composition comprising 10% by weight or more of the episulfide compound by polymerization in the presence of a polymerization catalyst and 0.001 to 3.0 parts by weight of a phenol derivative per 100 parts by weight of the episulfide compound or the composition, respectively; and
A process for producing a resin having a large refractive index which comprises curing an episulfide compound having one or more epithio structures represented by formula (1) in one molecule or a composition comprising 10% by weight of the episulfide compound by polymerization in the presence of 0.001 to 3.0 parts by weight of at least one polymerization catalyst selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts and secondary iodonium salts per 100 parts by weight of the episulfide compound or the composition, respectively.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The episulfide compound is used in the present invention so that the prepared optical material exhibits a large refractive index and a large Abbe number in an excellent balance. Therefore, it is preferable that R
1
in formula (1) represents methylene group or ethylene group and R
2
, R
3
and R
4
each represents hydrogen atom or methyl group. It is more preferable that R
1
represents methylene group and R
2
, R
3
and R
4
each represents hydrogen atom. n represents 0 or 1 and preferably 1. Y may represent either S or O. When a large refractive index is more important, it is preferable that Y represents S.
Among the above compounds having episulfide structures represented by formula (1) used in the present invention, compounds having two or more structures represented by formula (1) are preferable. Specific examples of the compound having the structure represented by formula (1) include the following compounds (A) to (E):
(A) Organic compounds having epithio groups excluding organic compounds (B) to (C) listed in the following
(B) Organic compounds having epithioalkyloxy groups
(C) Organic compounds having epithioalkylthio groups
(D) Organic compounds having epithioalkylseleno groups
(E) Organic compounds having epithioalkyltelluro groups Organic compounds (A), (B), (C), (D) and (E) have a chain backbone structure, an alicyclic backbone structure, an aromatic backbone structure or a heterocyclic backbone structure having nitrogen atom, oxygen atom, sulfur atom, selenium atom or tellurium atom. The organic compounds may have a combination of epithio group, epithioalkyloxy groups, epithioalkylthio groups, epithioalkylseleno group and epithioalkyltelluro group in one molecule. The organic compound may also have sulfide linkages, selenide linkages, telluride linkages, ether linkages, sulfone linkages, ketone linkages, ester linkages, amide linkages or urethane linkages.
Preferable examples of the organic compound having epithio groups of compound (A) include compounds obtained by replacing one or more epoxy groups in compounds having epoxy groups (not glycidyl groups) with epithio groups. Specific examples of the above compound include:
Organic compounds having a chain aliphatic backbone structure such as 1,1-bis(epithioethyl)methane, 1-(epithioethyl)-1-(&bgr;-epithlopropyl)methane, 1,1-bis(&bgr;-epithiopropyl)methane, 1-(epithioethyl)-1-(&bgr;-epithiopropyl)ethane, 1,2-bis(&bgr;-epithiopropyl)ethane, 1-(epithioethyl)-3-(&bgr;-epithiopropyl)butane, 1,3-bis(&bgr;-epithiopropyl)propane, 1-(epithioethyl)-4-(&bgr;-epithiopropyl)pentane, 1,4-bis(&bgr;-epithiopropyl)butane, 1-(epithio-ethyl)-5-(&bgr;-epithiopropyl)hexane, 1-(epithioethyl)-2-(&ggr;-epithiobutylthio)-ethane, 1-(epithioethyl)-2-[2-(&ggr;-epithiobutylthio)ethylthio]ethane, tetrakis-(&bgr;-epithiopropyl)methane, 1,1,1-tris(&bgr;-epithiopropyl)propane, 1,3-bis(&ggr;-epithiopropyl)-1-(&bgr;-epithiopropyl)-2-thiapropane and 1,5-bis(&bgr;-epithiopropyl)-2,4-bis(&bgr;-epithiopropyl)-3-thiapentane;
Compounds having an alicyclic backbone structure such as 1,3- and 1,4-bis(epithioethyl)cyclohexanes, 1,3- and 1,4-bis(&bgr;-epithiopropyl)cyclohexanes, bis[4-(epithioethyl)cyclohexyl]methane, bis[4-(&bgr;-epit
Horikoshi Hiroshi
Niimi Atsuki
Takasuka Masaaki
Takeuchi Motoharu
Yoshimura Yuichi
Antonelli Terry Stout & Kraus LLP
Buttner David J.
Mitsubishi Gas Chemical Company Inc.
LandOfFree
Process for producing a resin having a large refractive index does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for producing a resin having a large refractive index, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing a resin having a large refractive index will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3078829