Carbon fiber bundle containing sizing agent and method for producing same
AssigneeToray Industries, Inc.
InventorsTakayuki Yomo, Misato Takenaka, Haruki Okuda
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Abstract
A carbon fiber bundle containing a sizing agent particularly suitable for combination with a thermoplastic resin is provided, wherein the sizing agent has an appropriate level of bundling property for ease of handling and is susceptible to thermal degradation at temperatures low enough to maintain the surface properties of the carbon fibers, and wherein the residual amount of sizing agent can be reduced after the carbon fiber bundle is processed into an intermediate substrate, resulting in a reflection of the surface properties of the carbon fibers.
Claims7
A carbon fiber bundle comprising carbon fibers and a sizing agent that satisfies all of the following requirements (i) to (iv), and wherein a surface oxygen concentration of the carbon fiber is not less than 0.11 and not more than 0.25 as measured by X-ray photoelectron spectroscopy before the sizing agent is applied to the carbon fibers:
- (i) the sizing agent satisfies the requirement (a) or (b):
- (a) the percentage by mass of a polyalkylene glycol structure in the total sizing agent is not less than 80% by mass and the number-average molecular weight of the sizing agent is not less than 120 and less than 300;
- (b) the sizing agent has an acetylene structure and the percentage by mass of the polyalkylene glycol structure in the total sizing agent is not less than 20% by mass;
- (ii) the thermal weight loss ratio A determined under the following measurement conditions is not more than 5.0%;
- (iii) the thermal weight loss ratio B determined under the following measurement conditions is not less than 11.0%;
- (iv) the thermal weight loss ratio C determined under the following measurement conditions is not less than 90.0%:
- <thermal weight loss ratio A>
- the sizing agent weighing 10±2 mg (the weighed mass is represented by WA0 (mg)) is heated from 30° C. at a rate of 10° C./min with nitrogen gas flow of 200 milliliters (the volume is that under 1 atm at 25° C.) per minute by using thermogravimetry to measure the mass of the sizing agent when it has reached 140° C. (the measured mass is represented by WA1 (mg)), and the thermal weight loss ratio A is calculated by the following formula (A):
- thermal
-
- weight
-
- loss
-
- ratio
-
- A
-
- (
- %
- )
- =
- {
- (
- W
- A
-
- 0
- -
- W
- A
-
- 1
- )
- /
- W
- A
-
- 0
- }
- ×
- 100
- ;
- (
- A
- )
- <thermal weight loss ratio B>
- the sizing agent weighing 10±2 mg (the weighed mass is represented by WB0 (mg)) is heated from 30° C. at a rate of 10° C./min with nitrogen gas flow of 200 milliliters (the volume is that under 1 atm at 25° C.) per minute by using thermogravimetry to measure the mass of the sizing agent when it has reached 250° C. (the measured mass is represented by WB1 (mg)), and the thermal weight loss ratio B is calculated by the following formula (B):
- thermal
-
- weight
-
- loss
-
- ratio
-
- B
-
- (
- %
- )
- =
- {
- (
- W
- B
-
- 0
- -
- W
- B
-
- 1
- )
- /
- W
- B
-
- 0
- }
- ×
- 100
- ;
- (
- B
- )
- <thermal weight loss ratio C>
- the sizing agent weighing 10±2 mg (the weighed mass is represented by WC0 (mg)) is heated from 30° C. at a rate of 10° C./min with nitrogen gas flow of 200 milliliters (the volume is that under 1 atm at 25° C.) per minute by using thermogravimetry to measure the mass of the sizing agent when it has reached 350° C. (the measured mass is represented by WC1 (mg)), and the thermal weight loss ratio C is calculated by the following formula (C):
- thermal
-
- weight
-
- loss
-
- ratio
-
- C
-
- (
- %
- )
- =
- {
- (
- W
- C
-
- 0
- -
- W
- C
-
- 1
- )
- /
- W
- C
-
- 0
- }
- ×
- 100.
- (
- C
- )
Dependencies are inferred from the claim text.