1. An indeterminate copper material for electrolytic copper foil, wherein an average
grain size is in a range of 50 to 300 µm.
5 2. The indeterminate copper material of claim 1, wherein bulk density is in a range
of 1.0 to 3.0 g/cm3 and is defined by the following Equation 1:
[Equation 1]
bulk density (g/cm3) = total mass of indeterminate copper material (g)/1000 cm3,
wherein total mass of indeterminate copper material denotes total mass of the
10 indeterminate copper material filling a cubic box having a size of 10 cm×10 cm×10
cm in width, length and height.
3. The indeterminate copper material of claim 1 or 2, wherein a longest axis among
long axes on a cross section of the indeterminate copper material is 10 mm or more,
and
15 a shortest axis among short axes on the cross section is 5 mm or less.
4. The indeterminate copper material of claim 3, wherein the longest axis is in a
range of 10 to 75 mm, and the shortest axis is in a range of 1 to 5 mm.
5. A preparation method of the indeterminate copper material of claim 1 or 2,
comprising:
20 a) supplying a copper raw material;
b) melting the copper raw material; and
c) preparing an indeterminate copper material by melting the copper raw
material into molten copper and casting the molten copper.
6. The preparation method of claim 5, wherein c) comprises preparing an
25 indeterminate copper material by dispersing the molten copper, which is melted
14
from the copper raw material, in the form of particles and cooling the molten copper
while participating the molten copper in water contained in a water tank.
7. The preparation method of claim 6, wherein c) comprises preparing the
indeterminate copper material by dispersing the molten copper, which is melted
5 from the copper raw material, in the form of particles by dropping the molten copper
from a molten metal nozzle to an impaction plate on the water tank containing
water, and cooling the molten copper while precipitating the molten copper in the
water in the water tank.
8. The preparation method of claim 5, wherein a melting temperature of the molten
10 copper is in a range of 1,090 to 1,400 °C.
9. The preparation method of claim 7, wherein a distance between a discharge port
of the molten metal nozzle and an upper surface of the impaction plate is in a range
of 0.3 to 1.5 m.
10. The preparation method of claim 5, wherein oxygen content of the molten
15 copper is in a range of 20 to 1,000 ppm.