關於塑膠的硬度

測量硬度最普遍採用的儀器稱為肖氏（又稱為邵爾）硬度計。用一個彈簧將一金屬壓頭壓入材料的表面，並測量它能穿入多深。該儀器測量的穿入深度為零至0.100英寸。若尺規上的讀數為零則意味著壓頭穿入了極限深度，而讀數為100則意味著穿入深度為零。

有各種不同硬度範圍的肖氏硬度計。使用最普遍的標度之一是肖氏A級標度，使用一種較鈍的壓頭和彈力中等的彈簧。當讀數超過90以上時，肖氏A級硬度計就變得不是很精確。對於較硬的材料，則使用肖氏D級硬度計，因為它有一個銳利的壓頭和彈力較強的彈簧，可穿入較深的深度。

當測量更硬的塑膠時，就使用壓頭更銳利和彈力更強的硬度計，例如洛氏硬度計。而在另一極端，則使用肖氏00級硬度計，以測量軟的凝膠和軟泡沫橡膠。


REF: http://www.matweb.com/reference/shore-hardness.asp

The hardness of plastics is most commonly measured by the Shore (Durometer) test or Rockwell hardness test. Both methods measure the resistance of plastics toward indentation and provide an empirical hardness value that doesn't necessarily correlate well to other properties or fundamental characteristics. Shore Hardness, using either the Shore A or Shore D scale, is the preferred method for rubbers/elastomers and is also commonly used for 'softer' plastics such as polyolefins, fluoropolymers, and vinyls. The Shore A scale is used for 'softer' rubbers while the Shore D scale is used for 'harder' ones. Many other Shore hardness scales, such as Shore O and Shore H hardness, exist but are only rarely encountered by most plastics engineers.

The Shore hardness is measured with an apparatus known as a Durometer and consequently is also known as 'Durometer hardness'. The hardness value is determined by the penetration of the Durometer indenter foot into the sample. Because of the resilience of rubbers and plastics, the indentation reading my change over time - so the indentation time is sometimes reported along with the hardness number.