Cushioning material, packaging material, and packaged item

Abstract

A cushioning material cushions an external force applied to an electronic device. The cushioning material includes a support plate and a cushioning portion. The support plate is a member configured to support the electronic device. The cushioning portion is included in the support plate and cushions an external force applied to the electronic device. The cushioning portion includes a first cushioning portion and a second cushioning portion. The first cushioning portion has a first surface fixed to the support plate and a second surface facing the electronic device. The second cushioning portion has a third surface fixed to the support plate and a fourth surface facing the electronic device. In a graph where the vertical axis represents the external force applied to the electronic device and the horizontal axis represents the time since the external force starts to be applied to the electronic device, the types of waveforms of the graph of the first cushioning portion and the second cushioning portion are different.

What is claimed is: 
     
         1 . A cushioning material configured to cushion an external force applied to an electronic device, the cushioning material comprising:
 a support plate configured to support the electronic device; and   a cushioning portion provided at the support plate and configured to cushion an external force applied to the electronic device,   the cushioning portion including:
 a first cushioning portion including a first surface fixed to the support plate and a second surface facing the electronic device; and 
 a second cushioning portion including a third surface fixed to the support plate and a fourth surface facing the electronic device, wherein 
 in a graph in which a vertical axis represents an external force applied to the electronic device and a horizontal axis represents time from when the external force starts to be applied to the electronic device, types of waveforms of the graph are different between the first cushioning portion and the second cushioning portion. 
   
     
     
         2 . The cushioning material according to  claim 1 , wherein the first cushioning portion and the second cushioning portion are arranged in contact with each other. 
     
     
         3 . The cushioning material according to  claim 1 , wherein any one of the first cushioning portion and the second cushioning portion is arranged so as to be surrounded by the other one of the first cushioning portion and the second cushioning portion. 
     
     
         4 . The cushioning material according to  claim 2 , wherein the second surface and the fourth surface are flush with each other. 
     
     
         5 . The cushioning material according to  claim 1 , wherein the first cushioning portion includes a material of which the waveform is a trapezoidal wave, and the second cushioning portion includes a material of which the waveform is a half-sine wave. 
     
     
         6 . The cushioning material according to  claim 1 , wherein a material of the first cushioning portion is a corrugated cardboard material, and the second cushioning portion is made of a foamed resin material. 
     
     
         7 . A cushioning material configured to cushion an external force applied to an electronic device, the cushioning material comprising:
 a support plate configured to support the electronic device, and   a cushioning portion provided at the support plate and configured to cushion an external force applied to the electronic device,   the cushioning portion including:
 a first cushioning portion including a first surface fixed to the support plate and a second surface facing the electronic device; and 
 a second cushioning portion including a third surface fixed to the support plate and a fourth surface facing the electronic device, wherein 
 in a stress-strain diagram where a vertical axis represents compressive stress applied to the cushioning portion and a horizontal axis represents strain applied to the cushioning portion,
 (a) maximum stress in an elastic region of the first cushioning portion is larger than maximum stress in an elastic region of the second cushioning portion, 
 (b) a slope indicating a ratio of stress with respect to strain in a plastic region of the first cushioning portion takes a value of zero or close to zero, and a slope indicating a ratio of stress with respect to strain in a plastic region of the second cushioning portion takes a positive value larger than the value of the slope of the first cushioning portion, and 
 (c) maximum stress in an elastic region of a composite cushioning portion configured by arranging the first cushioning portion and the second cushioning portion in parallel in a direction facing the electronic device is larger than the maximum stress of the second cushioning portion, and the slope in the plastic region of the composite cushioning portion takes a positive value larger than the value of the slope of the first cushioning portion. 
 
   
     
     
         8 . The cushioning material according to  claim 7 , wherein the first cushioning portion is made of a corrugated cardboard material, and the second cushioning portion is made of a foamed resin material. 
     
     
         9 . The cushioning material according to  claim 1 , wherein the electronic device is a recording device. 
     
     
         10 . A packaging material comprising:
 a packaging box configured to accommodate the electronic device; and   the cushioning material according to  claim 1 .   
     
     
         11 . A packaged item comprising:
 the packaging material according to claim  10 ; and   the electronic device.