A long synthetic resin foam body composed of a thermoplastic resin expanded beads-molded substrate and a frame having displacement regulating sections provided at both ends in the longitudinal or lateral direction of the substrate and a connecting section that connects the displacement regulating sections to each other. The substrate has at least one joint forming portion that divides the substrate in a direction intersecting the connecting section into two or more substrate parts. The joint forming portion has a joint that connects the adjacent two substrate parts to each other and is deformable to permit a relative displacement between the adjacent two substrate parts when the substrate contracts or expands.

In a seat pad 10, a high ventilation member 12 higher in ventilation property than a seat pad member forming the seat pad 10 is embedded in a state of being exposed only to a rear side of the seat pad. The high ventilation member 12 is polyurethane foam subjected to membrane removal treatment, the polyurethane foam subjected to membrane removal treatment having a density of 20 kg/m.sup.3 to 40 kg/m.sup.3 and a number of cells of 45 cells or less per 25 mm.

In a seat pad 10, a high ventilation member 12 higher in ventilation property than a seat pad member forming the seat pad 10 is embedded in a state of being exposed only to a rear side of the seat pad. The high ventilation member 12 is polyurethane foam subjected to membrane removal treatment, the polyurethane foam subjected to membrane removal treatment having a density of 20 kg/m.sup.3 to 40 kg/m.sup.3 and a number of cells of 45 cells or less per 25 mm.

A vehicle seat for a vehicle. The vehicle seat includes a first foam and a second foam. The first foam has a rate sensitivity as measured in accordance with a modified ISO 3886/1 standard which can accommodate a slow speed test with a static strain rate of about 0.001 second.sup.1 and a high speed test with a dynamic strain rate of about 100 second.sup.1 such that the dynamic versus static strain rate increases by at least 200%, and the first foam is temperature stable such that the glass transition temperature of the first foam is less than or equal to zero degrees Celsius and a change in tan delta of less than or equal to 35% from a median value measured over a temperature range of from about negative 20 degrees Celsius to about 60 degrees Celsius.

A vehicle seat for a vehicle. The vehicle seat includes a first foam and a second foam. The first foam has a rate sensitivity as measured in accordance with a modified ISO 3886/1 standard which can accommodate a slow speed test with a static strain rate of about 0.001 second.sup.1 and a high speed test with a dynamic strain rate of about 100 second.sup.1 such that the dynamic versus static strain rate increases by at least 200%, and the first foam is temperature stable such that the glass transition temperature of the first foam is less than or equal to zero degrees Celsius and a change in tan delta of less than or equal to 35% from a median value measured over a temperature range of from about negative 20 degrees Celsius to about 60 degrees Celsius.

A cover (8) for a mattress (6) or a cushion (3) of a piece of furniture (1) with a utilized side (10) and a back side (11), wherein on the back side (11) there is a receiving device for bottom spring cushioning (12) which has spring strips (15), wherein at least one spring strip (15) is made of a fiber-reinforced plastic material with a preferably pultruded fiber core (16) and a plastic jacket (17) which surrounds the fiber core (16). It is provided that on opposite sides of the jacket (17) one jacket side (18) at a time sticks out for an enlarged support surface of the spring strip (15).

A cover (8) for a mattress (6) or a cushion (3) of a piece of furniture (1) with a utilized side (10) and a back side (11), wherein on the back side (11) there is a receiving device for bottom spring cushioning (12) which has spring strips (15), wherein at least one spring strip (15) is made of a fiber-reinforced plastic material with a preferably pultruded fiber core (16) and a plastic jacket (17) which surrounds the fiber core (16). It is provided that on opposite sides of the jacket (17) one jacket side (18) at a time sticks out for an enlarged support surface of the spring strip (15).

Provided is a core material of a seat cushion for a vehicle. The core material includes: a thermoplastic resin expanded beads molded article 2 that has a substantially rectangular shape in a top view, the rectangular shape having a long side and a short side; and an annular reinforcing member 3 that is insert-molded in the peripheral edge part of the expanded beads molded article. A missing part 4 is formed in the expanded beads molded article, the missing part passing through in the thickness direction. A slit 7 is formed in at least one corner of the lightening part, the slit being oriented outward from the expanded beads molded article from the vicinity of the corner part.

Provided is a core material of a seat cushion for a vehicle. The core material includes: a thermoplastic resin expanded beads molded article 2 that has a substantially rectangular shape in a top view, the rectangular shape having a long side and a short side; and an annular reinforcing member 3 that is insert-molded in the peripheral edge part of the expanded beads molded article. A missing part 4 is formed in the expanded beads molded article, the missing part passing through in the thickness direction. A slit 7 is formed in at least one corner of the lightening part, the slit being oriented outward from the expanded beads molded article from the vicinity of the corner part.

Provided is a core material of a seat cushion for a vehicle, including: a thermoplastic resin expanded beads molded article having a substantially rectangular shape in top view, that has thick portions on a front side and both sides of a circumferential portion thereof, and that has an occupant seating portion on an upper surface in an inner region thereof; and an annular frame member that is insert-molded at the circumferential portion of the thermoplastic resin expanded beads molded article. In the thermoplastic resin expanded beads molded article, formed are first slits having: slit pieces that extend along a front frame member at a position in front of the occupant sitting part and inside from the front frame part; and slit pieces that extend along a side frame member at a position outside from the occupant sitting part and inside from a side frame part.