Covering material, cable, and method of manufacturing cable

1. A cable covering material obtained from:

a resin component that comprises at least one of a crosslinkable resin having photo crosslinkability and thermal crosslinkability and a crosslinkable monomer having photo crosslinkability and thermal crosslinkability;

a photoinitiator, comprising a photo radical initiator and a photo cationic initiator, wherein the amount of the photoinitiator is 0.1 to 3.5 parts to 100 parts by mass of the resin component; and

a thermal initiator, comprising a thermal radical initiator and/or a thermal cationic initiator,

wherein a gel fraction of the cable covering material obtained from the resin is from 63.6-78.5%.

2. The cable covering material according to claim 1 , wherein the cable covering material is moldable by extrusion.

3. The cable covering material according to claim 1 , wherein the resin component comprises the crosslinkable resin having at least one selected from the group consisting of an acrylic group, a methacrylic group, a vinyl group, a vinyl ether group, an oxetane group, an epoxy group, an alicyclic epoxy group, an amino group, maleic acid, and maleic anhydride, and

wherein the crosslinkable resin occupies 5% by mass or more of a total mass of the resin component.

4. The cable covering material according to claim 3 , wherein, the crosslinkable resin comprises at least one selected from the group consisting of:

a polyolefin-based resin having at least one functional group selected from the group consisting of an acrylic group, a methacrylic group, a vinyl group, a vinyl ether group, an oxetane group, an epoxy group, an alicyclic epoxy group, an amino group, maleic acid, and maleic anhydride; and

a rubber-based resin having at least one functional group selected from the group consisting of an acrylic group, a methacrylic group, a vinyl group, a vinyl ether group, an oxetane group, an epoxy group, an alicyclic epoxy group, an amino group, maleic acid, and maleic anhydride.

5. The cable covering material according to claim 3 , wherein the crosslinkable resin comprises maleic acid modified polyolefin.

6. The cable covering material according to claim 1 , wherein the resin component comprises a crosslinkable monomer having at least one selected from the group consisting of an acrylic group, a methacrylic group, a vinyl group, a vinyl ether group, an oxetane group, an epoxy group, an alicyclic epoxy group, an amino group, maleic acid, and maleic anhydride.

7. The cable covering material according to claim 6 ,

wherein the cable covering material comprises 1 to 30 parts by mass of the crosslinkable monomer to 100 parts by mass of components excluding the crosslinkable monomer from the resin component.

8. The cable covering material according to claim 1 , wherein the resin component further comprises a non-crosslinkable resin.

9. The cable covering material according to claim 8 ,

wherein the non-crosslinkable resin comprises at least one selected from the group consisting of a polyolefin-based resin and a rubber-based resin.

10. The cable covering material according to claim 8 ,

wherein the non-crosslinkable resin comprises a linear low density polyethylene (LLDPE), an ethylene-vinyl acetate copolymer (EVA), and an ethylene-glycidyl methacrylate copolymer (EGMA).

11. A cable comprising:

a core; and

a cable covering material according to claim 1 that covers the core.

12. The cable covering material according to claim 1 , wherein the elongation under load of the cable covering material obtained from the resin is 68% to 85% and permanent elongation after cooling is 7% to 15% in a heat resistance evaluation test in accordance with JIS C 3660-2-1, the heat resistance evaluation test being conducted under conditions of:

Temperature: 200° C.,

Load: 20 N/cm 2 , and

Loading time: 15 minutes.