Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2000-06-26
2003-06-17
Berman, Susan W. (Department: 1711)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C522S096000, C522S097000, C522S173000, C385S145000
Reexamination Certificate
active
06579618
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a radiation-curable resin composition, and especially to a radiation-curable resin composition that is suitable as a coating material for substrates, in particular optical fibers.
BACKGROUND OF THE INVENTION
Optical fibers, especially, optical glass fibers, are fragile and easily damaged and hence these are coated with a coating material. The properties, specifically, the modulus of elasticity and the like of a coating film made of, for example, a UV-ray curable resin have a great influence on the transmission performances of optical fibers. When optical fibers are coated with a primary coating material having a high modulus of elasticity, the transmission loss of the optical fibers increases because of high lateral pressure. A material having a low modulus of elasticity is, therefore, desirable as the primary coating material. However, conventional coating materials having a low modulus of elasticity have the drawbacks that these materials have generally low breaking strength and are hence fragile. Specifically, it is desired that the modulus of elasticity of the primary coating material for optical fibers be 0.15 kg/mm
2
or less in terms of secant modulus, as determined according to JIS K7127, to absorb high lateral pressure. However, the breaking strength of cured products having such a low modulus of elasticity is as low as 0.15 kg/mm
2
or less in terms of the tensile strength at break, as determined according to JIS K7127. The products thus exhibit only poor practicability.
Furthermore, in spite of excellent transmission characteristics due to the low modulus of elasticity, such conventional radiation curable resin compositions have a drawback when used as the primary coating material for optical fibers. That is, when the primary coating material is removed to connect an optical fiber with another optical fiber, a portion of resinous material is left on the optical fibers. The complete removal of such resinous material remaining requires time-consuming procedures, impairing the processability of the material.
An object of the present invention is to provide a radiation-curable resin composition which is suitable for use as a substrate coating material, in particular, an optical fiber coating material, and, more particularly, as a primary coating material for optical fibers and which, after cure, has a high breaking strength while exhibiting a low modulus of elasticity.
Another object of the present invention is to provide a radiation curable resin composition suitable for use as a primary coating material for optical fibers, which can form a cured coating with a low modulus of elasticity exhibiting a high breaking strength and small light transmission loss, and yet be easily removed from optical fibers.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a coated optical fiber comprising: a coating having, a tensile strength at break of more than 0.15 kg/mm
2
and a secant modulus of 0.15 kg/mm
2
or less.
Furthermore the present invention provides a radiation curable resin composition comprising:
(A) a polymer containing polymerizable unsaturated groups in an average amount of 1.2 per molecule, a urethane bond in a molecular chain, and having a number average molecular weight from 3,000 to 30,000,
(B) a poly-functional monomer having two or more polymerizable unsaturated groups,
(C) a monomer having one polymerizable unsaturated group, and
(D) a radiation active initiator.
The composition can produce a cured product having at a thickness of 200 &mgr;m a secant modulus of 0.15 kg/mm
2
or less and a tensile strength of 0.15 kg/mm
2
or more when cured by ultraviolet radiation at a dose of 1 J/cm
2
in air.
The present invention further provides a radiation curable resin composition, which can produce a cured product having a total of at least two peaks or shoulders in a temperature range from −50° C. to +35° C., preferably at least one peak or shoulder in a temperature range from −50° C. to −20° C. and at least one peak or shoulder in a temperature range from −20° C. to +35° C., in a temperature dependency curve of loss tangent obtained from a temperature dependency measurement of a dynamic viscoelasticity ratio when cured by ultraviolet radiation at a dose of 1 J/cm
2
in air. Preferably this composition also comprises the above-mentioned components (A) through (D).
REFERENCES:
patent: 4932750 (1990-06-01), Ansel et al.
patent: 4962992 (1990-10-01), Chapin et al.
patent: 4973611 (1990-11-01), Puder
patent: 5881194 (1999-03-01), Duecker
patent: 5907023 (1999-05-01), Chawla
patent: 5977202 (1999-11-01), Chawla
patent: 6136880 (2000-10-01), Snowwhite et al.
patent: 6187835 (2001-02-01), Szum et al.
patent: 0301733 (1989-02-01), None
patent: 2163755 (1986-03-01), None
patent: 96/17000 (1996-06-01), None
patent: 97/19898 (1997-06-01), None
patent: 98/32780 (1998-07-01), None
patent: 99/08975 (1999-02-01), None
patent: 99/52958 (1999-10-01), None
Ishikawa Miyuki
Komiya Zen
Ukachi Takashi
Berman Susan W.
DSM N.V.
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