A modified conjugated diene-based polymer represented by Formula 1, wherein a terminal of a polymer chain is modified, and a method for preparing same are provided. By including a modifier derived unit having a specific structure, a beta value affecting cold flow may be reduced through controlling the degree of branch, and accordingly, the cold flow of a polymer may be efficiently controlled and a mooney viscosity increasing ratio may be improved.

The invention relates to a copolymer of ethylene and of a 1,3-diene of formula CH.sub.2═CR—CH═CH.sub.2, which copolymer bears an amine function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.

A method for producing a motor vehicle rim made of an aluminum alloy for a wheel of a motor vehicle, the motor vehicle rim having a rim base limited on opposite sides by an outer horn and an inner horn, a hub with a central recess and a hole circle, and a rim center connecting the rim base and the hub to one another. The motor vehicle rim is produced in one piece and continuously in a casting mold by die casting of a casting material, the casting material being the aluminum alloy.

In this pneumatic tire, a tan δ value T20 of a rubber member, which constitutes at least one of a bead filler, an undertread, a sidewall rubber, and a rim cushion rubber, at 20° C. and a tan δ value T60 of the rubber member at 60° C. satisfy 0.50≤T20/T60≤2.00 and T20≤0.22. Additionally, the tan δ value T20 of the rubber member at 20° C. is in a range T20≤0.15. Additionally, a tan δ value T20_sw of the sidewall rubber at 20° C. and a tan δ value T60_sw of the sidewall rubber at 60° C. satisfy 0.50≤T20_sw/T60_sw≤1.50 and T20_sw≤0.11.

A tire 2 has a nominal aspect ratio of 65% or less. The tire 2 includes a tread 4, a pair of sidewalls 6, a pair of chafers 8, a pair of beads 10, and a band 40. The band 40 includes a full band 44 having ends 44e opposed to each other across an equator plane, and a pair of edge bands 46 located outward of the ends 44e of the full band 44 in a radial direction. An outer surface of each chafer 8 has a fitting recess 62 into which a flange F of a rim R fits.

A color rubber composition for tires according to an embodiment contains a rubber component, a pigment other than black or white, a petroleum wax, and a white filler. The petroleum wax has a normal/iso ratio (mass ratio) of 70/30 to 90/10. The carbon number distribution for iso components in the whole petroleum wax is 1.0% or less for 25 or less carbon atoms, 4.0 to 8.0% for 26 to 32 carbon atoms, 5.0 to 15.0% for 33 to 44 carbon atoms, and 1.0% or more for 45 or more carbon atoms. The carbon number distribution for normal components in the whole petroleum wax is 5.0 to 18.0% for 25 or less carbon atoms, 40.0 to 48.0% for 26 to 32 carbon atoms, 15.0 to 27.5% for 33 to 44 carbon atoms, and 2.0% or more for 45 or more carbon atoms.

A tire masterbatch comprises natural rubber and cellulose nanofiber, wherein at least a portion of the cellulose nanofiber is such that length is 10 μm to 20 μm, and a ratio (i.e., L/D) of the length to a diameter is 1000 to 2000. A tire masterbatch manufacturing method comprises an operation in which at least a cellulose nanofiber slurry and a natural rubber latex are mixed to prepare a liquid mixture, and an operation in which the liquid mixture is coagulated, wherein at least a portion of cellulose nanofiber within the cellulose nanofiber slurry is such that length is 10 μm to 20 μm, and a ratio (i.e., L/D) of the length to a diameter is 1000 to 2000.

In a pneumatic tire, bead cores have a wire arrangement. In a cross-sectional view in a tire meridian direction, a tangential line and a contact point are defined. The tangential line contacts an innermost layer in a radial direction and the wire cross sections innermost and outermost in a lateral direction in the wire arrangement from a rim fitting surface side. The contact point of the tangent line is on the wire cross section on the outermost side. A gauge Wh in the lateral direction from the contact point to the rim fitting surface and an outer diameter φ of the bead wire have a relationship 2.0≤Wh/φ≤15.0. A radial height H2 of a contact portion between a body portion and a turned back portion of a carcass layer has a relationship 0.80≤H2/H1≤3.00 to a radial height H1 of the bead cores.

Provided is a pneumatic tire that has excellent fuel efficiency and rubber strength and combines high load capacity and space saving. A pneumatic tire mounted on a vehicle, comprises: a tread configured to come into contact with a road surface; and a belt layer located on an inner side of the tread in a tire radial direction, wherein an outer diameter of the pneumatic tire is 350 mm or more and 600 mm or less, the following relationship:

0.78≤RW/SW≤0.88 is satisfied, where RW is a rim width of a rim wheel to be attached to the pneumatic tire and SW is a tire section width of the pneumatic tire, and a rubber composition that contains: a rubber component containing a diene-based rubber; and a mercaptocarboxylic acid compound is used in the pneumatic tire.

In the pneumatic tire including a sealant layer containing an adhesive sealant on an inner surface of a tread portion, when a thickness of the sealant layer at 0° C. is G.sub.0, a thickness of the sealant layer at 50° C. is G.sub.50, a width of the sealant layer at 0° C. is W.sub.0, and a width of the sealant layer at 50° C. is W.sub.50, a rate of change R.sub.G of thickness expressed by R.sub.G=(|G.sub.50−G.sub.0|/G.sub.0)×100 is set to 3% or less, and a rate of change R.sub.W of width expressed by R.sub.W=(|W.sub.50−W.sub.0|/W.sub.0)×100 is set to 3% or less.