Flame-retardant insulation bar for windows and doors

A flame-retardant insulation bar manufactured by extruding an insulation composition comprising any one base resin selected from the group consisting of polyamide, polyurethane, polyester, and combinations thereof;

• a reinforcing agent;
• a nitrogen-based flame retardant;
• and an additive,
• the insulation composition comprising:
• 50 to 80 parts by weight of the base resin;
• 10 to 30 parts by weight of the reinforcing agent;
• 10 to 25 parts by weight of the flame retardant;
• and
• 5 to 15 parts by weight of the additive,
• wherein an amount of the base resin is at least half of a total amount of the insulation composition,
• a relative viscosity of the base resin is 1.5 to 2.5,
• the reinforcing agent is a glass fiber having an aspect ratio of 400 or less but greater than 1, and
• the flame-retardant insulation bar has heat conductivity of 0.5 W/m·K or less and a UL94 flame-retardant grade of V-0 or higher.