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...
Patent
1987-01-16
1988-08-09
Ziegler, Jacob
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...
524474, 524491, 526346, 526347, C08K 5011
Patent
active
047628782
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a polymer composition useful as a coating material for an optical fiber or as a hot melt adhesive.
BACKGROUND ART
Various coating materials have been used on optical fibers, for maintaining the strength of the fibers and protecting them from microbending, which induces optical loss. These materials include those which are cured by UV-ray or heat after being coated on the fibers, and those which are cured by evaporation of the solvent after coating with a material containing a solvent, as the main materials. Recently, however, for improving the workability in the coating step or physical properties of the coating material, as pointed out in Japanese unexamined patent publication (Kokai) No. 58-100102, hot melt materials have been used.
Also, there has been a demand for hot melt adhesives, in general, having an excellent adhesiveness at lower temperatures. The above mentioned Japanese unexamined patent publication (Kokai) No. 58-100102, proposed a hot melt composition which can be advantageously applied for optical fiber, but it did not have a sufficiently small modulus at low temperatures, which is an important physical property of the coating material for an optical fiber for the prevention of optical loss by microbending, and a coating material superior in various other points has been sought.
DISCLOSURE OF THE INVENTION
The present inventors have investigated hot melt coating materials under such circumstances, and consequently found that a specific novel polymer composition retains or improves most of the various advantageous hot melt materials for optical fiber of the prior art, and further avoids microbending loss, and thus the present invention was completed.
Further, it has been found that adhesiveness at lower temperatures can be remarkably improved by using this polymer composition as a conventional hot melt adhesive, whereby the invention as a hot melt adhesive was created.
SUMMARY OF THE INVENTION
The essence of the present invention resides in a polymer composition which comprises (A) 15 to 40% by weight of a hydrogenated product of a block copolymer comprising a vinyl aromatic compound (a.sub.1) and a conjugated diene compound (a.sub.2), (B) 4 to 30% by weight of an isopropenyltoluene polymer comprising meta-isopropenyltoluene as the main constituting unit, and (C) 40 to 80% by weight of a compound selected from the group consisting of .alpha.-olefin polymers (c.sub.1) having number average molecular weight of 250 to 5000 and squalane (c.sub.2), the total of the components (A), (B) and (C) is 100% by weight. The essence of the present invention also resides in a coating material for optical fiber containing said composition as the component and a hot melt adhesive containing said composition as the component.
Component (A)
The component (A) usable in the present invention is a hydrogenated product of a block copolymer comprising a vinyl aromatic compound (a.sub.1) and a conjugated diene compound (a.sub.2). The block copolymer is preferably linear, but may be radial or branched.
Examples of the vinyl aromatic compound are styrene, .alpha.-methylstyrene, vinyltoluene, p-tert-butylstyrene, vinylxylene, ethylvinylxylene, vinylnaphthalene, and mixtures thereof. Among them, styrene is particularly preferred. On the other hand, conjugated diene compounds may be exemplified by 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, halogenated derivatives thereof and mixtures thereof. Among them, butadiene or a combination of conjugated diene compounds composed mainly of butadiene is preferred, and particularly, butadiene is most preferable.
The block copolymer comprising a vinyl aromatic compound and a conjugated diene compound usable as the starting material for the hydrogenated product includes, for example, block copolymers as disclosed in Japanese unexamined patent publication (Kokai) No. 52-150457 or No. 53-71158, including those with the constitutions of X--Y--X.sup.1, X--Y, etc., in which X and X.sup.1 are blocks comprising
REFERENCES:
patent: 4503187 (1985-03-01), Gunesin et al.
Muro Tsuneaki
Takeda Masami
Mitsui Petrochemical Industries Ltd.
Ziegler Jacob
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