Heat insulation cover member for drip prevention or drip suppression of dew condensation water, covering member for other heat exchange pipes and ducts, piping structure and duct covering structure using same, electrical device box covering structure, nonwoven fabric to be used in said heat insulation cover member and method for using said nonwoven fabric in heat insulation cover member, and method for using said heat insulation cover member for various covering members including heat exchange p

A heat insulation cover member for drip prevention or drip suppression of dew condensation water, the heat insulation cover member comprising:

• a nonwoven fabric that is disposed on a surface of a resin foam, wherein:
• the resin foam is a polyethylene-based resin foam having closed cells and the nonwoven fabric is fixed to one surface of the resin foam by fusion or bonding;
• the nonwoven fabric is a laminate structured nonwoven fabric having a laminate structure of two layers;
• a first layer of the nonwoven fabric is formed only of thermoplastic resin fibers, and at least some of the thermoplastic resin fibers are fused or bonded to each other;
• a second layer of the nonwoven fabric is formed of a nonwoven fabric in which thermoplastic resin fibers are mixed with a predetermined amount of highly water absorbent resin fibers, and at least some of the thermoplastic resin fibers are fused or bonded to each other;
• the nonwoven fabric of the second layer includes, to total mass of the nonwoven fabric forming the second layer, 10% by mass or more and 80% by mass or less of the highly water absorbent resin fibers, and 20% by mass or more and 90% by mass or less of the thermoplastic resin fibers as the remainder;
• and
• either the first layer or the second layer of the nonwoven fabric is joined to the surface of the resin foam.

A nonwoven fabric to be used for a heat insulation cover member for drip prevention or drip suppression of dew condensation water, the nonwoven fabric comprising:

• thermoplastic resin fibers mixed with a predetermined amount of highly water absorbent resin fibers, wherein:
• a water retention parameter of the nonwoven fabric for retaining water against gravity is 0.70 or more, and water retention capacity of the nonwoven fabric determined under predetermined conditions satisfies 7.0 g or more;
• a product thickness of the nonwoven fabric is between 0.5 mm and 2.0 mm and a basis weight of the nonwoven fabric is between 30 g/m2 and 300 g/m2;
• the nonwoven fabric is formed of a nonwoven fabric including the thermoplastic resin fibers, having a fiber diameter in a range between 5 μm and 30 μm, at least some of which are fused or bonded to each other, mixed with the predetermined amount of the highly water absorbent resin fibers;
• the nonwoven fabric includes 10% by mass or more and 80% by mass or less of the highly water absorbent resin fibers, and 20% by mass or more and 90% by mass or less of the thermoplastic resin fibers as the remainder;
• the water retention parameter is a parameter calculated by:
• preparing a strip-shaped test piece having dimensions of 200 mm in length and 25 mm in width, providing a gauge line across a width of a surface of the test piece at the midpoint in a longitudinal direction, and dripping 400 μL of colored test liquid onto the gauge line while the test piece is held horizontally;
• holding the test piece vertically for five minutes immediately after dripping;
• and
• dividing an average value in a width direction of ascending distance from the gauge line to a point at which the test liquid reaches upward on the test piece by an average value in the width direction of descending distance from the gauge line to a point at which the test liquid reaches downward on the test piece, which is an index value using the ascending distance from the test piece gauge line and the descending distance from the test piece gauge line;
• and
• the water retention capacity is determined by inserting a refrigerant pipe having a length of 150 mm and a diameter of 25 mm with the heat insulating cover member attached to an outer periphery thereof, into a container containing 20 g of water, and then holding the container in a constant-temperature-and-humidity chamber at a temperature of 23° C. and a humidity of 30% for six hours, after which the container is removed and the water is removed, and the water retention capacity is determined from mass after water removal.