Seat core member, seat portion, and seat

1. A seat core member comprising:

a plurality of ridges that extend in a rising direction of the seat core member in a rising portion of the seat core member being in contact with a cushion layer and the rising portion being positioned in a front direction of the seat core member, in the seat core member of a seat portion provided with the seat core member including a hard synthetic resin foam which is at least one of the group consisting of a polypropylene-based resin foam, a polyethylene-based resin foam, and a polystyrene-based resin foam and the cushion layer including a soft synthetic resin foam which is a polyurethane-based resin foam and covering the seat core member.

2. The seat core member according to claim 1 ,

wherein the ridges are respectively formed in parallel, and a length of each of the ridges in the rising direction of the seat core member is at least ten times or more a width of the ridge.

3. The seat core member according to claim 1 ,

wherein each of the ridges extends in the rising direction of the seat core member as a continuous ridge.

4. The seat core member according to claim 1 ,

wherein the ridges have a height of 0.1 to 3 mm, a width of 0.1 to 1 mm, a groove width of 0.5 to 4 mm, and a ridge pitch of 1 to 5 mm.

5. The seat core member according to claim 4 ,

wherein the ridges have a height of 0.2 to 2 mm, a width of 0.2 to 1 mm, a groove width of 0.5 to 2 mm, and a ridge pitch of 1 to 3 mm.

6. The seat core member according claim 1 ,

wherein the hard synthetic resin foam that forms the seat core member is a polypropylene-based resin foam.

7. The seat core member according to claim 6 ,

wherein the polypropylene-based resin foam has an apparent density of 0.01 to 0.5 g/cm 3 .

8. The seat core member according to claim 1 ,

wherein the polyurethane-based resin foam has an apparent density of 0.01 to 0.1 g/cm 3 .

9. A seat comprising:

the seat core member according to claim 1 ; and

a backrest portion.