Shore durometer

Durometer hardness A material s hardness as measured by the Shore Durometer. 

Vickers and Knoop indentors, Barcol hardness, and Shore durometers (2) (b) to measure the resistance of a material to scratching by another material or by a sharp point, such as the Bierbaum hardness or scratch-resistance test and the Moh one for hardness and (c) to measure rebound efficiency or resilience, such as the various Rockwell hardness tests. The various tests provide different behavior characteristics for plastics, as described by different ASTM standards such as D 785. The ASTM and other sources provide different degrees of comparison for some of these tests. 

A hollow roller of wood or metal with an internal square housing to fit a suitable shaft, used for winding up fabric, rubber sheet, rubberised fabric, linings, etc. also termed roller or box. Shore Durometer See Durometer. 

Hardness measured on a Shore durometer. In addition to the commonly used Shore A scale there are several others O, OO, B, C and D, designed to open out either the soft or the hard end of the A scale. 

The shore durometer is a simple instrument used to measure the resistance of a material to the penetration of a blunt needle. In the Barcol approach, a sharp indentor is used to measure the ability of a sample to resist penetration by the indentor (Figure 14.18). The values given in Table 14.3 are for one specific set of conditions and needle area for the Barcol and Brinell hardness tests. 

The so-called brittle point, associated with sample failure in impact tests, may be determined qualitatively using a penetrometer or a Shore durometer (an instrument used to measure resistance of a sample to penetration by a blunt needle) to measure the change in penetration hardness with temperature. Also, a thin film of a polymer may be readily folded at temperatures above T but may crack when folded at temperatures below Tr... 

PVC,DOP Stress at 100% elongation p.s.i. Shore Durometer D hardness Volume resistivity, ohm-cm. 

The particular case of the hardness of rollers is covered by ISO 726734 36 which is in three parts dealing with the normal dead load method, Shore durometer and the Pusey Jones methods respectively. This last method is a very old hardness test which is now virtually never seen, although it is understood to still be popular in some circles for rollers. It is an amazing brass and chain contraption that uses a 3.175 mm indentor acting under a load of 1kg and without a surrounding foot. 

Hardness tests attract more interest in their accuracy, reproducibiliy and intercomparison than any other test - which is probably a result of them being simple tests which are carried out particularly frequently, and because the situation is confused with several scales. The fact that the situation is far from clear cut owes as much to history as to logic. If the Shore durometers had not been the first hardness meters, it is highly doubtful that we would now have spring loaded instruments mounted on stands or use damage prone indentors. Neither would the IRHD scale have been contrived to mimic the status quo. Such is the effect of powerful established interests. 

To meet specific needs, other additives such as lubricants, extenders, fillers, impact modifiers, and pigments are added to the PVC compound, in addition to heat stabilizers and plasticizers. Today, it is estimated that more than 60% of all the adducts used in plastics are used in PVC compounds. Although the earliest PVC compounds were produced as emulsions, essentially all PVC compounds are produced today as suspensions. Suspension compounds contain essentially no emulsifiers and are more processable. Liquid plastisols typically have room-temperature viscosities of less than 10,000 cp. Products made from plastisols are usually very soft. They have Shore Durometers of 55A and less, to as low as 30A, and they can have characteristic skin- or leather-like appearance and feel. 

Below 75A Shore Ourometer 75A or higher Shore Durometer... 

The so-called Shore hardnesses are measured differently for metals and plastics. With hard materials (metals), a scleroscope is used to measure the rebound of a small steel ball. This Shore hardness is thus measured by a dynamic method, which yields the rebound hardness (the impact elasticity of the rubber industry). Soft plastics, on the other hand, are tested with a Shore durometer. This measures the resistance to the penetration of the point of a cone through the contraction of a calibrated spring. The durometer thus works according to a static method, and yields the true Shore hardness as understood by the rubber industry. Like the Rockwell hardness, the Shore hardness is given in scale divisions. 

Thermal conductivity mW/MK Tensile strength MPa % Elongation Notched Izod impact J/m Coefficient of friction, 3.4 MPa load Wear factor 1/pPa Shore durometer hardness Specific gravity... 

Indentation hardness n. Resistance to penetration by an indenter. The hardness of a material as determined by either the size of an indentation made by an indenting tool under a fixed load, or the load needed to produce penetration of an indenter to a predetermined depth. The instruments commonly used with plastics are the Shore Durometer (indenter A for soft resins and elastomers, D for hard materials) described... 

D indicates a Shore Hardness of 60 on the Shore Durometer scale D ... 

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