Cushion material and cushion material manufacturing method
A cushion material with improved vibration absorptivity, and a cushion material manufacturing method for easily obtaining the cushion material are provided. The cushion material ( 1 ) includes a foam body ( 2 ) having a surface portion ( 20 ) formed of an air permeability control surface portion ( 21 ) and an air permeability uncontrol surface portion ( 22 ), and a covering material ( 3 ) configured to cover the air permeability uncontrol surface portion ( 22 ). The cushion material manufacturing method is a cushion material manufacturing method for obtaining the cushion material ( 1 ), and includes covering the air permeability uncontrol surface portion ( 22 ) of the foam body ( 2 ) with the covering material ( 3 ).
1. A cushion material comprising:
a foam body having a surface portion formed of an air permeability control surface portion and an air permeability uncontrol surface portion; and
a covering material comprising a sol substance, having an air permeability lower than that of the air permeability uncontrol surface portion, and configured to cover the air permeability uncontrol surface portion,
wherein the surface portion covers one of all faces of the foam body, wherein a surface air permeability of the air permeability control surface portion is 25 cc/cm 2 /sec or less as measured in compliance with JIS K 6400,
wherein a surface air permeability of the air permeability uncontrol surface portion is not controlled,
wherein a surface of the air permeability control surface portion has a small percentage of opening portions in which cell membranes are not formed on a cell frame compared to closed portions in which cell membranes are formed on the cell frame without breaking,
wherein a surface of the air permeability uncontrol surface portion has a small percentage of closed portions in which cell membranes are formed on the cell frame without breaking compared to opening portions in which cell membranes are not formed on the cell frame,
wherein the air permeability control surface portion and the air permeability uncontrol surface portion are on an identical face of the foam body,
wherein the foam body is in the shape of hexahedron, the identical face of foam body is one face among the six faces of the foam body, wherein a surface portion of remaining five faces consists of the air permeability control surface portion,
wherein the air permeability uncontrol surface portion includes an edge formed in the foam body,
wherein the covering material covers the edge of the identical face of the foam body such that the portion of the identical face of the foam body other than the edge thereof is free of the covering material.
2. The cushion material according to claim 1 , wherein the air permeability uncontrol surface portion includes a defective portion of the foam body.
3. The cushion material according to claim 2 , wherein an outflow speed of air discharged from inside of the foam body to outside of the foam body during vibration is substantially equal to an inflow speed of air flowing into the inside of the foam body during the vibration.
4. The cushion material according to claim 1 , wherein an inflow speed of air flowing into inside of the foam body during vibration is faster than an outflow speed of air discharged from the inside of the foam body to outside of the foam body during the vibration.
5. The cushion material according to claim 1 , wherein an outflow speed of air discharged from inside of the foam body to outside of the foam body during vibration is substantially equal to an inflow speed of air flowing into the inside of the foam body during the vibration.
6. The cushion material according to claim 1 , wherein an inflow speed of air flowing into inside of the foam body during vibration is slower than an outflow speed of air discharged from the inside of the foam body to outside of the foam body during the vibration.
7. The cushion material according to claim 1 , wherein the covering material includes a sheet member.