Patent ID: 8038758

Claim:
A mat material comprising: a mat base comprising an inorganic fiber and having a first surface and a second surface opposite to the first surface; a first sheet material provided on the first surface of the mat base to alleviate scattering of the inorganic fiber contained in the inorganic fiber mat base; a second sheet material provided on a second surface of the mat base to alleviate scattering of the inorganic fiber contained in the inorganic fiber mat base; the first and second sheet materials having elongation anisotropy in planes of the first and second surfaces, respectively; and a relationship θ A /θ dA <θ B /θ dB being satisfied between an angle θ A (about 0≦θ A ≦θ dA ) formed by an easy-to-elongate direction in the first sheet material relative to a longitudinal direction of the mat material and an angle θ B (about 0≦θ B ≦θ dB ) formed by an easy-to-elongate direction in the second sheet material relative to the longitudinal direction of the mat material, wherein a direction in which a value at about a 5% nominal strain represented by (a tensile load (N)/a nominal strain) in the planes of the sheet materials becomes minimum is defined as the easy-to-elongate direction and a direction in which the value becomes maximum is defined as a hard-to-elongate direction, and wherein an angle formed by the easy-to-elongate direction and the hard-to-elongate direction in the first sheet material is θ dA (about 0<θ dA ≦about 90°) and an angle formed by the easy-to-elongate direction and the hard-to-elongate direction in the second sheet material is θ dB (about 0<θ dB ≦about 90°).