Patent ID: 7060246

Claim:
Magnesium hydroxide particles having a hexagonal crystal form and having an aspect ratio (H) which satisfies the following expression (I), 0.45 ·A·B<H< 1.1 ·A·B (I) wherein H is an aspect ratio, A is an average secondary particle diameter (μm) of all of the magnesium hydroxide particles measured by a laser diffraction scattering method and B is a specific surface area (m 2 /g) of all of magnesium hydroxide particles measured by a BET method and wherein a volume ratio of magnesium hydroxide particles having a secondary particle diameter (F) satisfying the following expression (II) is at least 60% based on a volume of all of magnesium hydroxide particles, 0.3 ·A<F< 1.7 ·A (II) wherein F is a width of a secondary particle diameter (μm) distribution of the magnesium hydroxide particles, and A is as defined in the expression (I).