Flame-retardant flexible polymer composition, and polymer tube and insulated wire formed from the polymer composition

1. A flame-retardant flexible polymer composition comprising:

a polymer component that contains 98 to 90 parts by mass of a chlorinated polyethylene and 2 to 10 parts by mass of a polyolefin polymer; and

calcium hydroxide particles having a surface containing calcium silicate,

wherein a content of the particles relative to 100 parts by mass of the polymer component is 5 parts by mass or more and 10 parts by mass or less, and a chlorine content of the chlorinated polyethylene is 20% to 40% by weight,

wherein the polyolefin polymer is a high-density polyethylene polymer having a density of 0.95 g/cm 3 or more,

wherein the flame-retardant flexible polymer composition does not include a zeolite compound,

wherein the flame-retardant flexible polymer composition is irradiated with ionizing radiation to cross-link the polymer component, and

wherein after the flame-retardant flexible polymer composition is irradiated with ionizing radiation to cross-link the polymer component, the flame-retardant flexible polymer composition has a heat resistance such that the polymer composition has a tensile strength >8.3 MPa and a tensile elongation >175% after being stored at 121° C. for seven days, and the flame-retardant flexible polymer composition has an oil resistance such that the polymer composition has a tensile strength >6.9 MPa and a tensile elongation >175% after being immersed in an aircraft hydraulic fluid conforming to Military Specification MIL-H-5606 at room temperature for a day.

2. A polymer tube produced by shaping a flame-retardant flexible polymer composition into a tube, the polymer composition including a polymer component that contains 98 to 90 parts by mass of a chlorinated polyethylene and 2 to 10 parts by mass of a polyolefin polymer and calcium hydroxide particles having a surface containing calcium silicate in which a content of the particles relative to 100 parts by mass of the polymer component is 5 parts by mass or more and 10 parts by mass or less, and a chlorine content of the chlorinated polyethylene is 20% to 40% by weight, wherein the polyolefin polymer is a high-density polyethylene polymer having a density of 0.95 g/cm 3 or more; and by irradiating the polymer composition with ionizing radiation to cross-link the polymer component,

wherein the flame-retardant flexible polymer composition does not include a zeolite compound, and

wherein after the flame-retardant flexible polymer composition is irradiated with ionizing radiation to cross-link the polymer component, the flame-retardant flexible polymer composition has a heat resistance such that the polymer composition has a tensile strength >8.3 MPa and a tensile elongation >175% after being stored at 121° C. for seven days, and the flame-retardant flexible polymer composition has an oil resistance such that the polymer composition has a tensile strength >6.9 MPa and a tensile elongation >175% after being immersed in an aircraft hydraulic fluid conforming to Military Specification MIL-H-5606 at room temperature for a day.

3. An insulated wire comprising a conductor and an insulation covering the conductor, wherein the insulation is formed from a flame-retardant flexible polymer composition including a polymer component that contains 98 to 90 parts by mass of a chlorinated polyethylene and 2 to 10 parts by mass of a polyolefin polymer; and

calcium hydroxide particles having a surface containing calcium silicate in which a content of the particles relative to 100 parts by mass of the polymer component is 5 parts by mass or more and 10 parts by mass or less, and a chlorine content of the chlorinated polyethylene is 20% to 40% by weight,

wherein the polyolefin polymer is a high-density polyethylene polymer having a density of 0.95 g/cm 3 or more,

wherein the flame-retardant flexible polymer composition is irradiated with ionizing radiation to cross-link the polymer component in the insulation,

wherein the flame-retardant flexible polymer composition does not include a zeolite compound, and

after the flame-retardant flexible polymer composition is irradiated with ionizing radiation to cross-link the polymer component in the insulation, the flame-retardant flexible polymer composition has a heat resistance such that the polymer composition has a tensile strength >8.3 MPa and a tensile elongation >175% after being stored at 121° C. for seven days, and the flame-retardant flexible polymer composition has an oil resistance such that the polymer composition has a tensile strength >6.9 MPa and a tensile elongation >175% after being immersed in an aircraft hydraulic fluid conforming to Military Specification MIL-H-5606 at room temperature for a day.