1. A continuous or instrumented indentation testing device comprising an exterior support, a piston slidingly mounted in the said exterior support and comprising an indenter, means for damping and regulating a force applied to the piston, a displacement measurement system and a force measurement system wherein the indenter is made of a single piece, a displacement measurement system support being directly mounted on the said indenter, the displacement measurement system being mounted on the said displacement measurement system support and integral with the said single-piece indenter when the indenter is displaced, so that the displacement measurement system is linked to displacement of the indenter, the indentation testing device further comprising a removable lower base that is mounted on a sleeve of the exterior support, the removable lower base being mounted between the sleeve and a surface of a part that is tested with the indentation testing device, the removable lower base having a shape complementary to the part that is tested, the indenter sliding along an axis orthogonal to the surface of the part that is tested, and the indentation testing device does not have a solid frame.
2. The device according to claim 1, wherein the displacement of the piston is controlled by the hand of a user, a manipulating arm, a mechanical column, or a robot.
3. The device according to claim 1, wherein the means for damping and regulating the force applied to the piston is one of an elastic ring and a spring.
4. The device according to claim 1, further comprising a combination of displacement measurement systems distributed evenly around the indenter.
5. The device according to claim 1, further comprising two additional displacement measurement systems, wherein the displacement measurement system and the two additional measurement systems are arranged in an equilateral triangle around the indenter.
6. The device according to claim 1, wherein the device is mounted on an automated mechanical element as part of a manufacturing line.
7. The continuous or instrumented indentation testing device according to claim 1, wherein the lower base is transparent.
8. The continuous or instrumented indentation testing device according to claim 1, wherein the lower base comprises a magnetic element.
9. The continuous or instrumented indentation testing device according to claim 1, further comprising an automated displacement system associated with a piston.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for producing a PVC-free multilayer tube free from undesired kinking with more dependable peelability, the process comprising:
coextruding a first plastics material, a second plastics material, and a third plastics material;
molding a substantially coaxial and cylindrical multilayer tube during the coextruding, wherein the multilayer tube comprises:
a base layer bonded to at least one connection layer by at least one buffer layer arranged between the base layer and the at least one connection layer, a thickness of the at least one buffer layer being less than a thickness of the at least one connecting layer;
wherein the base layer comprises the first plastics material containing polyolefins in an amount of at least 25% by weight of the base layer, the at least one connection layer comprises the second plastics material containing polyolefins in an amount of at least 25% by weight of the at least one connection layer, and the at least one buffer layer comprises the third plastics material containing a modified polyolefin elastomer in an amount of at least 75% by weight of the at least one buffer layer; and
wherein the multilayer tube can be used to form a coil or a loop with a diameter of down to 50 mm without undesirable kinking; and
welding the at least one connection layer of the tube to form a peelable coil, such that upon peeling the coil, delamination of the at least one connection layer or delamination of the at least one connection layer and the at least one buffer layer prevents tears from propagating from the at least one connection layer to the base layer.
2. The process according to claim 1, further comprising: shock-cooling the multilayer tube by water after the molding.
3. The process according to claim 1, wherein the polyolefins of the first plastics material and the polyolefins of the second plastics material are a polypropylene having a density \u03c1\u22660.9 gcm3, and wherein the modified polyolefin elastomer is a styrene-ethylene-butylene-styrene rubber or a styrene-butylene-styrene rubber.
4. The process according to claim 1, wherein at least one of the first plastics material and the second plastics material contains polyolefins in an amount of at least 50% by weight, of the base layer for the first plastics material, and of the at least one connection layer for the second plastics material; and wherein the third plastics material contains a modified polyolefin elastomer in an amount of 100% by weight of the at least one buffer layer.
5. The process according to claim 4, wherein the buffer layer has a styrene content of from 13% to 30% by weight of the at least one buffer layer.
6. A process for producing a PVC-free multilayer tube free from undesired kinking with more dependable peelability, the process comprising:
coextruding a first plastics material, a second plastics material, and a third plastics material;
molding a substantially coaxial and cylindrical multilayer tube during the coextruding, wherein the multilayer tube comprises:
a base layer bonded to at least one connection layer by at least one buffer layer arranged between the base layer and the at least one connection layer, wherein
the base layer includes the first plastics material, the at least one connection layer includes the second plastics material, and the at least one buffer layer includes the third plastics material,
the at least one buffer layer has a higher elastomer content than each of a) the base layer and b) the connection layer, and
the at least one buffer layer has a thickness that is less than a thickness of the at least one connecting layer; and
welding the at least one connection layer of the tube to form a peelable coil, such that upon peeling the coil, delamination of the at least one connection layer or delamination of the at least one connection layer and the at least one buffer layer prevents tears from propagating from the at least one connection layer to the base layer.
7. The process according to claim 6, wherein the base layer has a thickness that is at least 800 \u03bcm.
8. The process according to claim 6, wherein the volume of the base layer constitutes more than 96% of the entire volume of the tube materials.
9. The process according to claim 6, wherein the at least one buffer layer has an elastomer content of greater than 75% by weight of the at least one buffer layer.
10. The process according to claim 6, wherein the at least one buffer layer has an elastomer content of 100% by weight of the at least one buffer layer.
11. The process according to claim 6, wherein the third plastics material is a styrene-butylene-styrene rubber.
12. A process for producing a PVC-free multilayer tube free from undesired kinking with more dependable peelability, the process comprising:
coextruding a first plastics material, a second plastics material, and a third plastics material;
molding a substantially coaxial and cylindrical multilayer tube during the coextruding, wherein the multilayer tube comprises:
a base layer bonded to at least one connection layer by at least one buffer layer arranged between the base layer and the at least one connection layer, wherein
the base layer comprises the first plastics material, the at least one connection layer comprises the second plastics material, and the at least one buffer layer comprises the third plastics material,
the at least one buffer layer is mechanically weaker than each of a) the base layer and b) the connection layer,
the at least one buffer layer has a thickness that is less than a thickness of the at least one connecting layer, and the third plastics material is a styrene-butylene-styrene rubber; and
welding the at least one connection layer of the tube to form a peelable coil, such that upon peeling the coil, delamination of the at least one connection layer or delamination of the at least one connection layer and the at least one buffer layer prevents tears from propagating from the at least one connection layer to the base layer.
13. The process according to claim 12, wherein the first plastics material and the second plastics material each include a polypropylene having a density \u03c1\u22660.9 gcm3, or a synthetic rubber based on isoprene, in an amount at least 25% by weight of, respectively, the base layer and the connection layer.
14. The process according to claim 13, wherein the styrene-butylene-styrene rubber is present in an amount of 100% by weight of the at least one buffer layer.