JP3479576B2 - Carbon fiber precursor acrylic fiber - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon fiber precursor acrylic fiber which is suitable for producing a carbon fiber having excellent quality and physical properties and has a remarkably improved processability in the production of the carbon fiber.

[0002]

Acrylic fibers are widely used as a precursor for the production of carbon fibers. 200-40 acrylic fibers
A general method for producing carbon fibers is to convert the fibers into flame resistant fibers by heat treatment in an acidic atmosphere of 0 ° C., and subsequently carbonize them in an inert atmosphere of at least 1000 ° C. The carbon fiber thus obtained is widely used as a suitable reinforcing fiber of a fiber-reinforced resin composite material due to its excellent physical properties. On the other hand, in the above carbon fiber production, fusion of acrylic single fibers occurs in the flameproofing step of converting acrylic fibers into flameproofed fibers, firing becomes uneven, fluff, and yarn breakage occur. A failure occurs.

In order to avoid this fusion, it is known that it is important to select an oil agent applied to the acrylic fiber before flame resistance, and many oil agents have been introduced. Silicone-based oil agents are most often used among the above oil agents because they have high heat resistance and effectively suppress fusion. However, although this oil agent exerts excellent performance in avoiding fusion, in the respective steps of flame resistance and carbonization, decomposition products of this oil agent, such as silicon oxide and silicon nitride, are generated, resulting in flame resistance and carbonization. It was found that it accumulates on the inner wall of the furnace and the exhaust gas treatment line, resulting in a decrease in operability.

[0004]

The object of the present invention is to effectively suppress the fusion of the precursor acrylic fiber or flame resistant fiber in the flame resistance process and the carbonization process, and to use the above-mentioned silicone oil agent. The purpose of the present invention is to provide a carbon fiber precursor acrylic fiber that does not cause a decrease in operability that occurs in some cases.

[0005]

That is, the gist of the present invention is to have an amide group at the terminal obtained by reacting (A) a condensate of a dibasic acid and a polyol having an oxyalkylene unit with an aliphatic alkanolamide. A mixture of the compound and the alkylene oxide adduct of the amide compound (B) obtained by reacting the polyamine and the fatty acid was applied to water-swelled acrylic fiber and dried and densified.
Carbon fiber precursor acrylic fiber containing 0. 1 to 0.8% by weight.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. The acrylic fiber used in the carbon fiber precursor acrylic fiber of the present invention is not particularly limited as long as it is an acrylic fiber containing acrylonitrile as a main component, but it is not limited to 95% by weight or more of acrylonitrile and a vinyl-based single monomer copolymerizable with acrylonitrile. Acrylic fiber composed of 5% by weight or less of a monomer is preferable. Further, at least one selected from the group of monomers such as acrylic acid, methacrylic acid, itaconic acid, or their alkali metal salts or ammonium salts, and acrylamide, in which the vinyl-based monomer has the action of promoting the flameproofing reaction. It is preferable that the monomer is to promote flame resistance.

The component (A) of the present invention is a compound having an amide group at the terminal obtained by reacting a condensate of a dibasic acid and a polyol having an oxyalkylene unit with an aliphatic alkanolamide. As the dibasic acid in the component (A), saturated dibasic acids such as adipic acid and sebacic acid can be preferably used.

As the polyol having an oxyalkylene unit, a compound having two or more active hydrogen groups such as an aliphatic polyhydric alcohol or a polyhydric phenol is added to an oxyethylene unit having 2 to 4 carbon atoms. , Oxypropylene unit, oxybutylene unit alone or 2
It may be a polyol or an alkylene oxide adduct which is randomly or block-added with at least one kind, and specific examples thereof include poly (ethylene glycol, poly (ethylene glycol), polytetramethylene ether glycol, etc., to which an alkylene oxide such as ethylene oxide, propylene oxide, etc. has been added. Examples thereof include ether polyols and polyether polyols having two or more ester bonds in the molecule. The molecular weight of the polyol is 500 to 1000
It is 0, preferably 1000 to 5000.

Component (B) is an alkylene oxide adduct of an amide compound obtained by reacting a polyamine with a fatty acid. As the polyamine, ethylenediamine, diethylenediamine, triethylenetetramine, phenylenediamine and the like are preferably used. Also, as fatty acids,
Fatty acids having 8 to 30 carbon atoms, preferably 12 to 12 carbon atoms
22 and more preferably saturated fatty acids. When the number of carbon atoms is less than 8, the heat resistance of the component (B) decreases,
If it exceeds the range, the dispersion in water as a dispersion medium becomes poor at the time of application to the acrylic fiber, which is not preferable.

The alkylene oxide to be added is an alkylene oxide having 2 to 4 carbon atoms, and examples thereof include ethylene oxide, propylene oxide and butylene oxide. The addition form of this alkylene oxide may be random or block. However, the number of added moles is 5
-100, preferably 10-30. If the number of added moles is less than 5, the dispersibility in water used as the dispersion medium tends to decrease, and if it exceeds 100, the heat resistance decreases and the difficulty of imparting to the fiber becomes remarkable.

The ratio of the component (A) and the component (B) applied to the carbon fiber precursor acrylic fiber of the present invention is 0.01 to 0.8 of the component (A) + component (B) based on the acrylic fiber. It is necessary to add weight%. If the content of the above-mentioned components is less than 0.01% by weight, winding around the roller or guide is likely to occur, and if it exceeds 0.8% by weight, fusion is likely to occur. The amount of component (A) + component (B) applied to the fiber is determined by extraction with methyl Soxtone ketone for 1 hour using a Soxhlet extractor.

The ratio of the component (A) and the component (B) to be applied is not particularly limited, but among them, the components (A) and (B) are (A) :( B) = 9: 1 to 1: 1. 9 is preferably included. The ratio of the component (A) to the component (B) is more preferably (A) :( B) = 8: 2 to 5: 5. In the present invention, a silicone-based oil agent and an antioxidant may be added within a range that does not impair the functional expression of the component (A) and the component (B).

[0013]

EXAMPLES The present invention will be described in more detail below with reference to examples. The number of fusion bonds, the flameproof carbonization process passability and the strand strength were evaluated by the following methods. (Number of fusions) Carbon fibers were cut into a length of 3 mm, dispersed in acetone, and stirred for 10 minutes using a magnetic stirrer to count the total number of single fibers and the number of fusions, and the number of fusions per 100 fibers Was calculated. ⊚: fusion number (pieces / 100 pieces) <1 Δ: 1 ≦ fusion number (pieces / 100 pieces) <10 x: 10 ≦ fusion number (pieces / 100 pieces)

(Passability in flameproof carbonization process) Evaluation was made according to the following criteria according to the presence of guides, winding on rollers, and spread of tow in each process. ◎: No tow spread, no wrapping △: Toe spread, no wrapping ×: Toe spread, wrapping

(Strand Strength) JIS R-7601
The tensile properties of epoxy resin-impregnated strands are
The points were measured and shown as an average value.

Synthesis Example (A) A terminal amide obtained by reacting 0.8 mol of oleic acid diethanolamide with a condensate of 1.5 mol of adipic acid and 1 mol of an adduct of 20 mol of ethylene oxide with hydrogenated castor oil ether. 70 parts by weight of the compound, (B) 1 mol of diethylenetriamine and 2 mol of stearic acid were reacted, and 10 mol of an ethylene oxide adduct of an amide compound was obtained 3
0 parts by weight were mixed, dispersed in water and emulsified.

(Example 1) An acrylonitrile copolymer was dissolved in dimethylacetamide to obtain a polymer concentration of 21% by weight.
6, a spinning stock solution having a viscosity of 500 poise at 60 ° C. was prepared, and a coagulation bath filled with 69 wt% dimethylacetamide aqueous solution at 35 ° C. had a pore size of 0.075 mmφ and a pore number of 12
A draft ratio of 0.8 was discharged from a spinneret of 000 to obtain a coagulated yarn. The coagulated yarn was desolvated in a water washing tank and stretched 5 times to obtain a water-swelled acrylic fiber.

After introducing the water-swelled acrylic fiber into a tank filled with the emulsion obtained in the synthesis example in which the concentration was controlled so that the amount applied to the fiber was 0.4% by weight, the emulsion was applied. Then, it was dried and densified with a heating roll having a surface temperature of 130 ° C., and further stretched 1.7 times between heating rolls having a surface temperature of 170 ° C. to obtain a precursor acrylic fiber. This precursor acrylic fiber has a single yarn fineness of 1.1 denier, a tensile strength of 7 g / denier and an elongation of 10.5%, and the amount of the component (A) and the component (B) applied to the fiber is 0.4% by weight. there were.

This precursor acrylic fiber is used in the range of 230-270.
It passed through a flameproofing furnace having a temperature gradient of ° C for 60 minutes, and was further fired in a carbonization furnace having a temperature gradient of 300 to 1300 ° C in a nitrogen atmosphere to obtain carbon fibers. Table 1 shows the process passability during these processes, the fusion number of the obtained carbon fibers, and the strand strength.

(Example 2) The coagulated yarn obtained by spinning the same spinning dope as in Example 1 was drawn 1.5 times in air,
Acrylic fibers in a water swollen state were obtained in the same manner as in Example 1 except that the fibers were stretched 3.5 times in a washing bath.

This water-swelled acrylic fiber was introduced into a tank filled with the emulsion obtained in the synthesis example, and after the emulsion was applied, it was dried and densified with a heating roll having a surface temperature of 130 ° C., and further in pressurized steam. The precursor acrylic fiber was obtained by stretching 2.5 times. The precursor acrylic fiber had a single yarn fineness of 1.1 denier, a tensile strength of 7 g / denier and an elongation of 13%, and the amount of the component (A) and the component (B) applied to the fiber was 0.5% by weight. .

The precursor acrylic fiber was flame-resistant and carbonized under the same conditions as in Example 1 to obtain a carbon fiber. Table 1 shows the process passability during these processes, the fusion number of the obtained carbon fibers, and the strand strength.

(Embodiment 3) The concentration of the emulsion is increased and the amount of the component (A) and the component (B) applied to the fiber is 0.7.
A carbon fiber was obtained in the same manner as in Example 1 except that the weight percentage was changed. Table 1 shows the flame resistance, the process passability during the carbonization process, the fusion number of the obtained carbon fibers, and the strand strength.

(Comparative Example 1) The concentration of the emulsion was increased and the amount of the component (A) and the component (B) applied to the fiber was 1.5.
A carbon fiber was obtained in the same manner as in Example 1 except that the weight percentage was changed. Table 1 shows the flame resistance, the process passability during the carbonization process, the fusion number of the obtained carbon fibers, and the strand strength.

[0025]

[Table 1]

[0026]

According to the present invention described above, it occurs when the fusion of the precursor acrylic fiber or the flameproof fiber is effectively suppressed in the flameproofing step and the carbonization step, and the silicone-based oil agent is used. A carbon fiber precursor acrylic fiber that does not cause deterioration in operability is obtained.

Continuation of the front page (56) Reference JP-A-8-260254 (JP, A) JP-A-9-78340 (JP, A) International Publication 97/09474 (WO, A1) (58) Fields investigated (Int. Cl. ⁷ , DB name) D01F 6/18 D01F 9/22 D01F 11/06 D06M 13/402-13/438

Claims (2)

(57) [Claims] 1. A compound having a terminal amide group obtained by reacting a condensate of a dibasic acid and a polyol having an oxyalkylene unit with an aliphatic alkanolamide, and (B) reacting a polyamine with a fatty acid. A carbon fiber precursor acrylic fiber containing 0.01 to 0.8% by weight of the mixture, which is obtained by applying a mixture of the obtained amide compound and an alkylene oxide adduct to water-swelled acrylic fiber and subjecting the mixture to dry densification. 2. The mixture ratio of (A) and (B) in the mixture of (A) and (B) is (A) :( B) = 8: 2 to 5: 5. Carbon fiber precursor acrylic fiber.