Submarine optical cable with water-blocking filling composition
View Patent ↗Optical cable, in particular for submarine connections. A water blocking resin filling composition of reduced hardness is disposed into interstices. Preferably, the resin composition is a polyurethane resin having less than about 35% by weight of a polyol/polyisocyanate mixture and about 60% to about 90% by weight of a mineral oil. The polyurethane resin preferably has less than about 12% by weight of a coupling agent. The cable has an optical core surrounded by a plurality of metallic wires and an outer polymeric sheath. The optical core is of the “tight” type with a plurality of optical fibers embedded into a polymeric matrix disposed around a strength member.
1. An optical cable comprising:
an outer sheath;
an optical core disposed within said outer sheath, said optical core comprising at least one optical fiber housed therein; and
at least one longitudinal cavity disposed along and in contact with said optical core;
wherein said at least one longitudinal cavity is at least partially filled with a resin material having a needle penetration higher than about 200 1/10 mm, measured according to ASTM D 5-65,
wherein said resin material is obtained from a liquid curable composition comprising a polyol/polyisocyanate mixture, mineral oil, and an ester coupling agent in an amount greater than about 2% by weight and less than about 12% by weight.
2. The optical cable according to claim 1 , wherein said resin material has a needle penetration higher than about 240 1/10 mm.
3. The optical cable according to claim 1 , wherein said resin is a polyurethane-based resin.
4. The optical cable according to claim 1 , wherein said optical core comprises at least one optical fiber embedded into a matrix of polymeric material.
5. An optical cable comprising:
an outer sheath;
an optical core disposed within said outer sheath, said optical core comprising at least one optical fiber housed therein;
at least one longitudinal cavity disposed along and in contact with said optical core;
wherein said at least one longitudinal cavity is at least partially filled with a polyurethane resin obtainable from a liquid curable composition comprising less than about 35% by weight of a polyol/polyisocyanate mixture and about 65% to about 90% by weight of a mineral oil,
wherein said liquid curable composition further comprises an ester coupling agent in an amount greater than about 2% by weight and less than about 12% by weight.
6. The optical cable according to claim 5 , wherein the amount of the polyol/polyisocyanate mixture in said liquid curable composition is about 15% to about 25%.
7. The optical cable according to claim 5 , wherein the amount of the polyol/polyisocyanate mixture in said liquid curable composition is about 10% to about 30% by weight.
8. The optical cable according to claim 7 , wherein said polyol/polyisocyanate mixture comprises about 60% to about 85% of a polyol and about 15% to about 40% by weight of a polyisocyanate.
9. The optical cable according to claim 7 , wherein said polyol/polyisocyanate mixtures comprises about 65% to about 80% of a polyol and about 20% to about 35% by weight of a polyisocyanate.
10. The optical cable according to claim 5 , wherein said amount of mineral oil in said liquid curable composition is about 65% to about 85%.
11. The optical cable according to claim 5 , wherein said amount of mineral oil in said liquid curable composition is about 68% to about 80% by weight.
12. The optical cable according to claim 5 , wherein said ester coupling agent is an ester of a dicarboxylic acid.