| 摘要 |
PROBLEM TO BE SOLVED: To provide a white film excellent in whiteness, reflection property, lightweightness, and dimensional stability under heat, and to provide a surface light source having improved brightness property by using the same. SOLUTION: In the white film comprising a resin (B) that is incompatible with a crystalline resin (A) (hereinafter referred to as incompatible resin (B)) as resin particles (II) in the matrix at least containing the crystalline resin (A) and has a layer (layer S) having air babbles inside, under the conditions of the melting point of the resin (A) Tm+20°C and a shear rate of 200 sec<SP>-1</SP>, the melt viscosity of resin (A) of η1 (Pa s) and that of resin (B) of η2 (Pa s) satisfy following relations (1) and (2): (1)-0.3≤log<SB>10</SB>(η2/η1)≤0.55 and (2) 0.5≤log<SB>10</SB>(η2)/log<SB>10</SB>(η1)≤1.3. The white film satisfying the relations described above and a surface light source using the same are provided. COPYRIGHT: (C)2009,JPO&INPIT |
