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
2000-01-21
2002-04-23
Tucker, Philip (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...
C528S015000, C528S031000, C528S025000, C556S451000
Reexamination Certificate
active
06376601
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a high-refractive-index optical silicone oil and to a high-refractive-index optical silicone oil mixture. More particularly, this invention relates to a high-refractive-index optical silicone oil and a high-refractive-index optical silicone oil mixture comprising a pentasiloxane having terminal aralkyl groups, wherein the oil has a refractive index from 1.45 to 1.50 at 25° C.
BACKGROUND OF THE INVENTION
Optical silicone oils, like optical adhesives and optical greases, are used as fillers between lenses and between prisms in optical devices and as fillers in the connectors used for optical fibers. However, when an optical silicone oil is employed as the fill between lenses or prisms or between the terminal surfaces of optical fibers, any residual bubbles present in the silicone oil and/or bubbles produced along the interface between the silicone oil and lens, prism, or optical fiber terminal function to scatter the transmitted light or optical signal and thereby cause flare or transmission losses. To counter this, low-viscosity phenyl-type silicone oils with viscosities (25° C.) in the range from 1 to 70 mm
2
/s and refractive indices (25° C.) in the range from 1.46 to 1.51 have been used as optical silicone oils. Unfortunately, the phenyl-type silicone oils typically have broad molecular weight distributions, which has led to the problem of timewise changes in the refractive index due to volatilization of the phenyl-type silicone oil in the low molecular weight region.
Within the realm of the 2-methylphenethyl-functional optical silicone oils, Japanese Laid Open (Kokai or Unexamined) Patent Application Number Hei 6-92973 (92,973/1994) teaches a disiloxane having a 2-methylphenethyl group at one or both terminals. Due to its narrow molecular weight distribution, this disiloxane offers the advantage of undergoing no change in refractive index even when some amount of volatilization occurs. However, the disiloxane itself still suffers from a high volatility.
SUMMARY OF THE INVENTION
The present inventors have discovered that the aforementioned problems can be solved by using a pentasiloxane having terminal aralkyl groups.
In specific terms, the object of the present invention is to provide a low-volatility high-refractive-index optical silicone oil and a low-volatility high-refractive-index optical silicone oil mixture that undergo very little change in refractive index upon volatilization.
The present invention is directed to a high-refractive-index optical silicone oil comprising a pentasiloxane having the formula:
RMe
2
SiO(Me
2
SiO)
3
SiMe
2
R
wherein Me is methyl, each R is independently a C
8
to C
12
aralkyl, and the silicone oil has a refractive index of from 1.45 to 1.50 at 25° C.
The present invention is also directed to a method of preparing a high-refractive-index optical silicone oil having a refractive index of from 1.45 to 1.50 at 25° C., comprising reacting a C
8
to C
12
aryl-containing olefin with a pentasiloxane having the formula:
HMe
2
SiO(Me
2
SiO)
3
SiMe
2
H
in the presence of a supported platinum catalyst.
The present invention is further directed to a high-refractive-index optical silicone oil mixture, comprising a pentasiloxane having the formula:
RMe
2
SiO(Me
2
SiO)
3
SiMe
2
R
wherein Me is methyl, each R is independently a C
8
to C
12
aralkyl, and a disiloxane having the formula:
RMe
2
SiOSiMe
2
R
wherein Me and R as defined above and wherein the mixture has a refractive index of from1.45 to 1.50 at 25° C.
The present invention is still further directed to a method of preparing a high-refractive-index optical silicone oil mixture having a refractive index of from 1.45 to 1.50 at 25° C., comprising reacting a C
8
to C
12
aryl-containing olefin with a mixture comprising a pentasiloxane having the formula:
HMe
2
SiO(Me
2
SiO)
3
SiMe
2
H
and a disiloxane having the formula:
HMe
2
SiOSiMe
2
H
REFERENCES:
patent: 3088964 (1963-05-01), Ryan
patent: 3186964 (1965-06-01), Kookootsedes et al.
patent: 3839384 (1974-10-01), Morehouse
patent: 5300669 (1994-04-01), Akamatsu
patent: 6133394 (2000-10-01), Furukawa et al.
patent: 0 641 799 (1995-03-01), None
patent: 6092973 (1994-04-01), None
patent: 11158188 (1999-06-01), None
patent: WO 00/27348 (2000-05-01), None
Kobayashi Hideki
Okawa Tadashi
Tateishi Mari
Brown Catherine U.
Dow Corning Toray Silicone Co. Ltd.
Milco Larry A.
Peng Kuo-Liang
Tucker Philip
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