| 摘要 |
PROBLEM TO BE SOLVED: To manufacture a mattress which can be smoothly bent, is light in weight, and shows excellent durability.SOLUTION: A mattress has a three-dimensional net-like structure which is made of polyester and is configured to have a curled spring structure of filaments randomly brought into contact with one another in a tangled manner, to have a three-dimensional striped sparse-dense structure, and to have a surface layer of a thickness of 0.3 to 3.5 mm, of a bulk density of 0.028 to 0.444 g/cmand a part excluding the surface layer in an extrusion direction in such a manner to have the large bulk density in the surface layer and to have a wire diameter of φ0.2 to 1.3 mm and the bulk density of 0.01 to 0.2 g/cm. A swelling ratio is shown as D/Drelative to a shear rate when molten polyester is extruded from a capillary having a tube inner diameter Dof φ1.0 mm and a length of 10 mm at a temperature of 210°C, the extruded filament is cooled down, and Ddenotes a diameter of a cross section of the filament. The swelling ratio in a range of the shear rate of 25 to 1000/sec is 1.00 to 1.60.SELECTED DRAWING: Figure 1 |
