Abstract: A performance evaluation method for elastic material including rubber or elastomer, the method includes: a step of applying a strain to a test piece made of an elastic material to form at least one low-density portion inside the test piece; after forming the low-density portion, a step of obtaining projected images of the test piece by irradiating the test piece with X-rays at a predetermined first time and at a second time after the first time; a step of identifying the low-density portion based on the projected images at the first time; a step of identifying the low-density portion based on the projected images at the second time; a step of identifying a volume change of the at least one low-density portion between the first time and the second time; and a step of outputting the volume change as one of indicators of performance of the elastic material.

Abstract: A performance evaluation method for elastic material including rubber or elastomer, the method includes a step of applying a strain to a test piece made of the elastic material to form at least one void inside the test piece, a step of obtaining projected images of the test piece by irradiating the test piece with X-rays at a plurality of times after the at least one void is formed, and a step of obtaining a volume change of the at least one void between the plurality of times based on the projected images, as one of indexes of performance.

Abstract: A pneumatic tire includes bead cores, a carcass ply, an inner liner and the tread, and the crosslinked rubber composition, of the present invention, wherein the tread and the crosslinked rubber composition have a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a ratio of 40% by mass or more of a component having a weight-average molecular weight of not less than 1,000,000 in a molecular weight distribution measured by gel permeation chromatography are excellent in abrasion resistance.

Abstract: The pneumatic tire of the present invention characterized by comprising: bead cores, a carcass ply, an inner liner and a tread having a volume of the low density region of 35% or more, at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a glass transition temperature of ?20° C. or lower, and the crosslinked rubber composition of the present invention having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a glass transition temperature of ?20° C. or lower are excellent in abrasion resistance.

Abstract: A performance evaluation method for elastic material including rubber or elastomer, the method includes a strain applying step of applying a strain to a test piece made of an elastic material, an imaging step of obtaining projected images of the test piece being strained by irradiating X-rays to the test piece, a detection step of detecting low-density regions in the test piece based on the projected images, wherein each low-density region is a region where density of a part of the elastic material becomes lower than that before receiving the strain, a relationship obtaining step of obtaining a density distribution between the densities and frequency of the low-density regions based on the detected low-density regions, and a distribution width calculation step of calculating a distribution width specified by a full width at half maximum FWHM from the density distribution approximated to a normal distribution.

Abstract: A pneumatic tire includes bead cores, a carcass ply, an inner liner, and a tread having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a hardness of 65 or more and the crosslinked rubber composition of the present invention having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a hardness of 65 or more are excellent in abrasion resistance.

Abstract: The pneumatic tire characterized by comprising the tread and the crosslinked rubber composition, of the present invention, wherein the tread and the crosslinked rubber composition comprise two or more kinds of rubber components and a filler and have a volume of the low density region of 35% or more, a volume of the void portion of 7.5 or less and a filler distribution D represented by the following formula (I) of 2.0 or less are excellent in abrasion resistance. D=(A1/B1)/(A0/B0)??(I) In the formula (I), A1 represents a volume fraction of a rubber component A in a filler gel, B1 represents a volume fraction of a rubber component B in a filler gel, A0 represents a volume fraction of a compounded rubber component A, B0 represents a volume fraction of a compounded rubber component B.

Abstract: The pneumatic tire of the present invention characterized by comprising: bead cores, a carcass ply, an inner liner disposed at an inner side than the carcass ply in a direction of a tire diameter, and a tread disposed at an outer side than the carcass ply in a direction of a tire diameter and having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index ?G* shown by the following equation (I) of 3 or less and the crosslinked rubber composition having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index ?G* shown by the following equation (I) of 3 or less are excellent in abrasion resistance.

Abstract: A method for observing deformation of an elastic material including rubber or elastomer, includes a first step of capturing projection images of at least a part of the elastic material from directions perpendicular to an arbitrary axis of the elastic material and a second step of constructing a three-dimensional image of the elastic material from the projection images. The first step includes deforming the elastic material in predetermined constant cycles, outputting capture signals at the same time points of the predetermined constant cycles, and capturing the projection images based on the respective capture signals.

Abstract: The present invention provides a modified natural rubber having a good balance of improved fuel economy, heat-aging resistance, processability, and breaking resistance, and a method for producing such a rubber. The present invention also provides a tire rubber composition and a pneumatic tire which are prepared using the modified natural rubber. The present invention relates to a highly purified, modified natural rubber whose pH is adjusted to 2 to 7.

Abstract: A pneumatic tire includes bead cores, a carcass ply, an inner liner and the tread, and the crosslinked rubber composition, of the present invention, wherein the tread and the crosslinked rubber composition have a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a ratio of 40% by mass or more of a component having a weight-average molecular weight of not less than 1,000,000 in a molecular weight distribution measured by gel permeation chromatography are excellent in abrasion resistance.

Abstract: The pneumatic tire of the present invention characterized by comprising: bead cores, a carcass ply, an inner liner and a tread having a volume of the low density region of 35% or more, at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a glass transition temperature of ?20° C. or lower, and the crosslinked rubber composition of the present invention having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a glass transition temperature of ?20° C. or lower are excellent in abrasion resistance.

Abstract: The pneumatic tire of the present invention characterized by comprising: bead cores, a carcass ply, an inner liner disposed at an inner side than the carcass ply in a direction of a tire diameter, and a tread disposed at an outer side than the carcass ply in a direction of a tire diameter and having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index ?G* shown by the following equation (I) of 3 or less and the crosslinked rubber composition having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index ?G* shown by the following equation (I) of 3 or less are excellent in abrasion resistance.

Abstract: A pneumatic tire includes bead cores, a carcass ply, an inner liner, and a tread having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a hardness of 65 or more and the crosslinked rubber composition of the present invention having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a hardness of 65 or more are excellent in abrasion resistance.

Abstract: The pneumatic tire characterized by comprising the tread and the crosslinked rubber composition, of the present invention, wherein the tread and the crosslinked rubber composition comprise two or more kinds of rubber components and a filler and have a volume of the low density region of 35% or more, a volume of the void portion of 7.5 or less and a filler distribution D represented by the following formula (I) of 2.0 or less are excellent in abrasion resistance. D=(A1/B1)/(A0/B0)??(I) In the formula (I), A1 represents a volume fraction of a rubber component A in a filler gel, B1 represents a volume fraction of a rubber component B in a filler gel, A0 represents a volume fraction of a compounded rubber component A, B0 represents a volume fraction of a compounded rubber component B.

Abstract: The present invention provides a method for evaluating the rebound resilience, hardness, or energy loss of polymer materials, capable of sufficiently evaluating the difference in performance between samples with excellent measurement accuracy. The present invention relates to a method for evaluating the rebound resilience, hardness, or energy loss of a polymer material, including irradiating the polymer material with X-rays or neutrons to perform X-ray scattering measurement or neutron scattering measurement.

Abstract: To observe an elastic material under a dynamically deformed state. [Solution] A method for observing deformation of an elastic material 1 including rubber or elastomer, and an apparatus for capturing a projection image of the elastic material suitably used therefor. The observing method includes: a projection image obtaining step S1 of capturing a projection image of at least a part of the elastic material 1, from a direction perpendicular to an arbitrary axis of the elastic material 1, at a plurality of capture positions P around the axis; a three-dimensional image constructing step S2 of constructing a three-dimensional image 51 of the elastic material 1 from the projection images, and a step of observing the three-dimensional image 51.

Abstract: A method of evaluating the neutron scattering length density, capable of accurately determining the neutron scattering length density is provided. The method evaluates the neutron scattering length density of scatterers in a material, including determining the neutron scattering length density based on a scattering intensity curve obtained by neutron scattering measurement, with use of a scattering intensity curve obtained by X-ray scattering measurement.

Abstract: The present invention provides a method for evaluating energy loss in a polymeric material, wherein the method provides sufficient evaluation of the difference in performance between samples with excellent measurement accuracy; a method for evaluating chipping resistance of a polymeric material, wherein the method provides evaluation in a short period of time and at low cost with excellent measurement accuracy; and a method for evaluating abrasion resistance of a polymeric material, wherein the method provides sufficient evaluation of the difference in performance between samples with excellent measurement accuracy. The present invention relates to methods for evaluating energy loss, chipping resistance, and abrasion resistance of a polymeric material, and the methods include irradiating the polymeric material with X-rays or neutrons to perform X-ray scattering measurement or neutron scattering measurement.

Abstract: The present invention provides a modified natural rubber having a good balance of improved fuel economy, heat-aging resistance, processability, and breaking resistance, and a method for producing such a rubber. The present invention also provides a tire rubber composition and a pneumatic tire which are prepared using the modified natural rubber. The present invention relates to a highly purified, modified natural rubber whose pH is adjusted to 2 to 7.