Rigidity reinforcement insulation sheet


The D461/D461S rigidity reinforcement insulation sheets are mica sheets developed for the purpose of reducing the weight and reinforcing the rigidity of mechanical components used for laptops. The D461S is a product that has improved the surface smoothness of D461.


  • (1) They have excellent strength, and fragments are not scattered even when subjected to impact.
  • (2) They have high compressive strength and can be designed to thin and lighten the product for its slight curve and warp.
  • (3) Thanks to excellent workability, cutting, machining, and punching can be done easily.
  • (4) They have obtained the UL94-V1 standard. (D461: from 1 mm, D461S: from 0.3 mm)
  • (5) They have smooth surface and texture like glass.


  • (1) Rigidity reinforcement board for laptops
  • (2) Touchpad inductor

Composition and standard dimensions

D461 D461S
Mica Mica paper based on uncalcined muscovite
Binder Epoxy
Standard thickness (mm) 0.20 to 20.00 0.30 to 1.0
Standard dimensions (mm) 600 × 1000

Other sizes are available upon request.


D461 D461S
Nominal thickness mm 0.55 0.50
Apparent density kg/m3 2.2 × 103 2.5 × 103
Dielectric breakdown strength kV/mm 56 54
Insulation resistance Normal state 2000 or more 2000 or more
Surface resistivity Ω 7× 1014 1× 1015
Dielectric constant 60Hz F/m 4.0 5.9
1MHz 3.9 5.2
Dielectric tangent 60Hz % 1.4 0.7
1MHz 0.5 0.5
Flexural strength MPa 418 483
Elastic modulus in bending GPa 55 77
Thermal conductivity W/m·K 0.42 0.43
Surface roughness (Ra) μm 0.62
Arc resistance S 181 181
Comparative tracking index (CTI) V 600
Combustibility 94V-1 (t1.0 mm or more) 94V-1 (t0.3 mm or more)
94V-0 (t5.0 mm or more)

*Measured in compliance with JIS C 2116 and JIS K 6911.
*The above values are examples from tests, and are not guaranteed values.