Carbon-fiber-precursor acrylic fiber bundle with oil composition adhering thereto, process for producing the same, oil composition for carbon-fiber-precursor acrylic fiber, and oil composition dispersion for carbon-fiber-precursor acrylic fiber

1. A carbon-fiber-precursor acrylic fiber bundle with an oil composition adhering thereto, wherein:

the oil composition comprises an amino-modified silicone, an aromatic ester compound (1) having a structure of formula (1):

and an aromatic ester compound (2) having a structure of formula (2):

an adhesion amount of the amino-modified silicone is from 0.01 to 0.2% by mass relative to a mass of the dry fiber,

a total adhesion amount of the aromatic ester compound (1) and the aromatic ester compound (2) is from 0.4 to 1.2% by mass relative to the mass of the dry fiber,

a ratio of the adhesion amounts of the aromatic ester compound (2) to the aromatic ester compound (1) is from 0.25 to 6.5,

R 1 and R 2 are each independently a hydrocarbon group having 7 to 21 carbon atoms,

m and n are each independently an integer of from 1 to 5, and

R 3 , R 4 , and R 5 are each independently a hydrocarbon group having 8 to 10 carbon atoms.

2. The fiber bundle according to claim 1 , wherein the amino-modified silicone is an amino-modified silicone having a structure of formula (3):

wherein o is an integer of from 5 to 300, and p is an integer of from 1 to 5.

3. The fiber bundle according to claim 1 , wherein the amino-modified silicone has a kinematic viscosity of from 50 to 500 mm 2 /s at 25° C.

4. The fiber bundle according to claim 1 , wherein a block copolymerization polyether comprising a propylene oxide unit and an ethylene oxide unit and having a structure of formula (4):

H—O C 2 H 4 O x C 3 H 6 O y C 2 H 4 O z —H  (4)

is further adhered in a quantity of from 5 to 70 parts by mass relative to 100 parts by mass representing a total adhesion amount of the aromatic ester compound (1), the aromatic ester compound (2), and the amino-modified silicone to the dry fiber,

wherein x, y, and z are each independently an integer of from 1 to 200.

5. The fiber bundle according to claim 1 , wherein the amino-modified silicone has a kinematic viscosity of from 50 to 300 mm 2 /s at 25° C.

6. An oil composition comprising an amino-modified silicone, an aromatic ester compound (1) having a structure of formula (1):

and an aromatic ester compound (2) having a structure of formula (2):

wherein:

a content of the amino-modified silicone is from 1 to 25 parts by mass relative to 100 parts by mass of a total quantity of the aromatic ester compound (1) and the aromatic ester compound (2), and

a mass ratio of the aromatic ester compound (2) to the aromatic ester compound (1) is from 0.25 to 6.5,

R 1 and R 2 are each independently a hydrocarbon group having 7 to 21 carbon atoms,

m and n are each independently an integer of from 1 to 5, and

R 3 , R 4 , and R 5 are each independently a hydrocarbon group having 8 to 10 carbon atoms.

7. The oil composition according to claim 6 , wherein the amino-modified silicone is an amino-modified silicone having a structure of formula (3):

wherein o is an integer of from 5 to 300, and p is an integer of from 1 to 5.

8. The oil composition according to claim 6 , wherein the amino-modified silicone has a kinematic viscosity of from 50 to 500 mm 2 /s at 25° C.

9. The oil composition according to claim 6 , further comprising a block copolymerization polyether comprising a propylene oxide unit and an ethylene oxide unit and having a structure of formula (4):

H—O C 2 H 4 O x C 3 H 6 O y C 2 H 4 O z —H  (4)

in a quantity of from 10 to 50 parts by mass relative to 100 parts by mass of a total quantity of the amino-modified silicone, the aromatic ester compound (1), and the aromatic ester compound (2),

wherein x, y, and z are each independently an integer of from 1 to 200.

10. An oil composition dispersion, wherein the oil composition according to claim 6 is dispersed in water or a solvent.

11. The oil composition dispersion according to claim 10 , wherein the oil composition forms micelles with an average particle size of from 0.01 to 0.50 μm.

12. A process for producing a carbon-fiber-precursor acrylic fiber bundle with an oil composition adhering thereto, comprising:

applying an oil composition dispersion obtained by dispersing the oil composition according to claim 6 in water or a solvent, forming micelles with an average particle size of from 0.01 to 0.50, to a carbon-fiber-precursor acrylic fiber bundle in a water-swelled state, and

performing drying densification of the carbon-fiber-precursor acrylic fiber bundle.

13. The oil composition according to claim 6 , wherein the amino-modified silicone has a kinematic viscosity of from 50 to 300 mm 2 /s at 25° C.