RFID MODULE, AND PNEUMATIC TIRE WITH THE SAME EMBEDDED THEREIN
Provided are an RFID (radio frequency identification) module and a pneumatic tire in which the RFID module is embedded. An RFID module includes an IC (integrated circuit) substrate that stores data, an antenna that transmits and receives data, and a covering layer that covers the antenna. The covering layer contains calcium carbonate, and a relative dielectric constant of the covering layer is 7 or less.
1 . An RFID (radio frequency identification) module, comprising:
an IC (integrated circuit) substrate configured to store data;
an antenna configured to transmit and receive the data; and
a covering layer configured to cover the antenna;
the covering layer containing calcium carbonate and having a relative dielectric constant of 7 or less.
2 . The RFID module according to claim 1 , wherein the covering layer is formed of rubber or elastomer and 20 phr or more of calcium carbonate.
3 . The RFID module according to claim 2 , wherein the covering layer includes 20 phr to 55 phr of calcium carbonate.
4 . The RFID module according to claim 1 , wherein the covering layer has a thickness ranging from 0.5 mm to 3.0 mm.
5 . The RFID module according to claim 1 , wherein the covering layer has a dielectric loss tangent of 0.1 or less, a surface resistivity of 10 12 Ωm or more, and a volume resistivity of 10 12 Ωm or more.
6 . The RFID module according to claim 1 , wherein the covering layer has a storage modulus E′c (20° C.) at 20° C. ranging from 2 MPa to 12 MPa.
7 . The RFID module according to claim 1 , wherein the covering layer has a glass transition temperature ranging from −70° C. to −45° C.
8 . A pneumatic tire in which the RFID module according to claim 1 is embedded, comprising:
a tread portion extending in a tire circumferential direction and having an annular shape;
a pair of sidewall portions disposed on both sides of the tread portion;
a pair of bead portions disposed on inner sides in a tire radial direction of the pair of sidewall portions; and
a carcass layer mounted between the pair of bead portions.
9 . The pneumatic tire according to claim 8 , wherein a relative dielectric constant of the covering layer is lower than a relative dielectric constant of a rubber member disposed adjacent to the covering layer.
10 . The pneumatic tire according to claim 8 , wherein the RFID module is disposed on an outer side in a tire width direction of the carcass layer, and a storage modulus E′c (20° C.) at 20° C. of the covering layer and a storage modulus E′out (20° C.) at 20° C. of a rubber member having the largest storage modulus at 20° C. of rubber members located on an outer side in the tire width direction of the RFID module satisfy the relationship 0.1≤E′c (20° C.)/E′out (20° C.)≤1.5.
11 . The pneumatic tire according to claim 8 , wherein a center of the RFID module is disposed 10 mm or more spaced from a splice portion of a tire component in the tire circumferential direction.
12 . The pneumatic tire according to claim 8 , wherein the RFID module is disposed between a position on an outer side in the tire radial direction by 15 mm of an upper end of a bead core of a bead portion of the pair of bead portions and a tire maximum width position.
13 . The pneumatic tire according to claim 8 , wherein a distance between a cross-sectional center of the RFID module and a tire surface is 1 mm or more.
14 . The pneumatic tire according to claim 8 , wherein the antenna has a helical shape.