Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1999-03-02
2001-11-20
Berman, Susan W. (Department: 1711)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C385S114000, C385S115000, C385S123000, C385S145000, C522S114000, C522S116000, C522S117000, C522S120000, C522S121000, C522S129000, C522S122000, C522S015000, C522S025000
Reexamination Certificate
active
06319603
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid curable resin composition. More particularly, the present invention relates to a liquid photo-curable resin composition which upon radiation produces cured products which exhibit superior heat resistance, excellent mechanical strength, and superb adhesive characteristics. The composition is suitable as a photo-curable adhesive, a photo-curable sealing material, a resin for optical three-dimensional molding, and a coating material for optical fibers, optical fiber ribbon matrix, and the like.
2. Description of Prior Art
Among photo-curable resin compositions, acrylate-based resin compositions have been developed as a material with characteristics suitable for a variety of applications by blending urethane acrylate as a major component of acrylate monomers. On the other hand, epoxy-based photo-curable resin compositions are used for applications making good use of the excellent adhesive properties and the high heat resistance of the epoxy resin.
A coating material for optical fibers is one specific application of photo-curable resins. As the use of optical fiber cables advances, higher durability is demanded of the coating material. Specifically, there is a problem wherein coloring of the optical fiber coating materials may be so detonated due to poor durability of the coating material that it becomes difficult to differentiate one optical fiber cable from another with a different color by sight. This may cause problems in the maintenance of optical fiber cables. Deterioration in color visibility has been confirmed to be caused not only by the discoloration of the bundling materials, but also by the discoloration of the primary and secondary coating that cover the individual optical fibers.
High adhesive properties and superior durability sufficient to prevent discoloration are demanded for photo-curable adhesives depending on the application. In addition, optical characteristics must not change in adhesives used for glass lenses and adhesives used to join quartz glass and optical fibers.
Urethane acrylate-based materials used in photo-curable resin compositions which are used for a variety of applications are flexible materials possessing superior mechanical characteristics such as high tenacity. Epoxy-based materials, on the other hand, are used for applications requiring the excellent characteristics of the epoxy resin, such as high adhesive properties and superior heat resistance.
However, the epoxy-based materials possess inadequate tenacity, while the urethane acrylate-based materials lack heat resistance. There are no known materials which possess both the characteristics possessed by these two types of resin materials.
Accordingly, an object of the present invention is to provide a liquid curable resin composition which undergoes the least change in characteristics when exposed to heat and light, maintains its transparency or is more resistant to coloration, exhibits superior mechanical characteristics and excellent adhesive properties. Such a resin composition is preferably formulated as to be suitable as a photo-curable adhesive or a coating material for optical fibers.
SUMMARY OF THE INVENTION
This object of the present invention can be achieved in the present invention by a liquid curable resin composition comprising,
(1) a poly(meth)acrylate polymer having a weight average molecular weight relative to polystyrene standards of at least 5,000,
(2) a ring-opening polymerizable monomer containing at least one epoxy group, and
(3) a cationic photopolymerization initiator.
DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS
Preferred examples of the above-mentioned (meth)acrylate polymer (1) include homopolymers of a (meth)acrylate compound, copolymers of two or more (meth)acrylate compounds, or copolymers of at least one (meth)acrylate compound and at least one radically polymerizable vinyl compound.
Such a (meth)acrylate polymer (1) can be manufactured by the polymerization of at least one (meth)acrylate compound or the polymerization of at least one (meth)acrylate compound and a vinyl compound which is radically polymerizable with the (meth)acrylate compound in the presence of a radical polymerization initiator.
The polymerization reaction can be carried out without using a solvent. When the molecular weight of the resulting poly(meth)acrylate is large and the polymer has such high viscosity that it is difficult to handle it with ease, an epoxy group-containing monomer polymerizable by the ring-opening reaction, which is later described in detail, can be used as a solvent.
Examples of the (meth)acrylate compounds include (meth)acrylates containing an alicyclic structure, such as isobornyl(meth)acrylate, bornyl(meth)acrylate, tricyclodecanyl(meth)acrylate, dicyclopentanyl(meth)acrylate, dicyclopentenyl(meth)acrylate, cyclohexyl(meth)acrylate, and 4-butylcyclohexyl(meth)acrylate. Other suitable (meth)acrylate include those having an epoxy group. Such a (meth)acrylate compound comprises preferably one (meth)acrylate group, and one epoxy group, and such compound has a molecular wight of less than 400. Commercially available epoxy group-containing (meth)acrylates, include 3,4-epoxy cyclohexylmethyl (meth)acrylate and glycidyl(meth)acrylate. Other suitable acrylates include hydroxyl group-containing (meth)acrylates, such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, and 2-hydroxybutyl(meth)acrylate; aminoalkyl(meth)acrylate such as diethylaminoethyl(meth)acrylate and 7-amino-3,7-dimethyloctyl(meth)acrylate; the compounds represented by the following formula (1),
CH
2
═C(R
1
)—COO(R
2
O)
m
—R
3
(1)
wherein R
1
is a hydrogen atom or a methyl group, R
2
is an alkylene group having 2-6, preferably 2-4, carbon atoms, R
3
is a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or an alkyl substituted aryl group having 1-24 carbon atoms preferably 1-16 carbon atoms, and m is an integer of 0-12, and preferably 0-8; and the compounds represented by the following formula (2),
CH
2
═C(R
1
)—CO—(OR
4
CO)
P
—O—CH
2
—R
9
(2)
wherein R
1
is the same as defined above, R
4
is an alkylene group having 2-8, preferably 2-5, carbon atoms, R
9
is a tetrahydrofurfuryl group, and p is an integer of 1-8, and preferably 1-4.
The compounds represented by the above formula (1) include, for example, methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl (meth)acrylate, butyl(meth)acrylate, amyl(meth)acrylate, isobutyl(meth)acrylate, t-butyl(meth)acrylate, pentyl(meth)acrylate, isoamyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, octyl(meth)acrylate, iso-octyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl(meth)acrylate, decyl(meth)acrylate, iso-decyl(meth)acrylate, undecyl(meth)acrylate, dodecyl(meth)acrylate, lauryl(meth)acrylate, stearyl(meth)acrylate, iso-stearyl(meth)acrylate, butoxyethyl(meth)acrylate, ethoxydiethylene glycol(meth)acrylate, benzyl(meth)acrylate, phenoxyethyl(meth)acrylate, ethoxylated nonylphenol acrylate, propoxylated nonylphenol acrylate, polyethylene glycol mono(meth)acrylate, polypropyleneglycol mono(meth)acrylate, methoxydiethylene glycol(meth)acrylate, ethoxyethyl(meth)acrylate,methoxypolyethylene glycol(meth)acrylate, methoxypolypropylene glycol(meth)acrylate, polypropyleneglycol mono(meth)acrylate, methoxydiethylene glycol(meth)acrylate, ethoxyethyl(meth)acrylate, methoxypolyethylene glycol(meth)acrylate, and methoxypolypropylene glycol(meth)acrylate. Tetrahydrofurfuryl(meth)acrylate is given as an example of the compounds represented by the above-mentioned formula (2).
Among the above-described (meth)acrylate compounds, the (meth)acrylate compounds containing an epoxy group can be used as one of the reactants in the manufacture of the poly(meth)acrylate polymer, so that the polymer comprises epoxy groups, for the purpose of accelerating the grafting reaction between the second component (the ring-opening polymerizable monomer containing an epoxy group) and the fi
Komiya Zen
Ukachi Takashi
Watanabe Tsuyoshi
Yamaguchi Yoshikazu
Berman Susan W.
DSM N.V.
Pillsbury & Winthrop LLP
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