Patent ID: 7247661

Claim:
A masterbatch pellet mixture comprising a mixture of a high specific gravity masterbatch pellets group (A) with specific gravity within a range from 1.8 to 3.5, and a low specific gravity masterbatch pellets group (B) with specific gravity within a range from 0.5 to 1.6, wherein the high specific gravity masterbatch pellets group (A) comprises m different columnar masterbatch pellets from type 1 through to type m, each with a different specific gravity, the low specific gravity masterbatch pellets group (B) comprises n different columnar masterbatch pellets from type 1 through to type n, each with a different specific gravity, and the high specific gravity masterbatch pellets group (A) and the low specific gravity masterbatch pellets group (B) satisfy a formula (1) shown below: 0.5 ⁢ ⁢ ( mm - 1 ) ≦ ∑ p = 1 m ⁢ ( Hp Sp × Rp ) - ∑ q = 1 n ⁢ ( Hq Sq × Rq ) ≦ 12 ⁢ ⁢ ( mm - 1 ) ⁢ . ( 1 ) wherein symbols in the formula are defined as follows: m: an integer from 1 to 10 n: an integer from 1 to 10 p: a type number of columnar masterbatch pellets within the high specific gravity masterbatch pellets group (A) q: a type number of columnar masterbatch pellets within the low specific gravity masterbatch pellets group (B) Hp: a height (mm) of columnar masterbatch pellets of type p within the high specific gravity masterbatch pellets group (A) Sp: a bottom surface area (mm 2 ) of columnar masterbatch pellets of type p within the high specific gravity masterbatch pellets group (A) Rp: a mass proportion of the mass of the type p columnar masterbatch pellets relative to a total mass of the high specific gravity masterbatch pellets group (A) Hq: a height (mm) of columnar masterbatch pellets of type q within the low specific gravity masterbatch pellets group (B) Sq: a bottom surface area (mm 2 ) of columnar masterbatch pellets of type q within the low specific gravity masterbatch pellets group (B) Rq: a mass proportion of the mass of the type q columnar masterbatch pellets relative to a total mass of the low specific gravity masterbatch pellets group (B).