JP4699821B2 - Acrylic fiber oil for carbon fiber production - Google Patents

Description

The present invention relates to an acrylic fiber (hereinafter referred to as a precursor) oil agent for producing carbon fibers which is suitable for producing carbon fibers having excellent quality and strength and which is excellent in process passability in the production of carbon fibers.

Carbon fibers are widely used for aerospace applications, sports applications, general industrial applications and the like as reinforcing fibers for composite materials with plastics called matrix resins, utilizing their excellent mechanical properties. In recent years, in particular, from the viewpoint of energy saving by reducing the weight of products and reducing CO2 emissions, the superiority of lightweight and high-strength carbon fiber composite materials is increasing, and the demand for higher performance is increasing. The high performance of this composite material is very dependent on the characteristics of the carbon fiber itself, and the demand for high performance of the composite material, that is, the demand for high performance of the carbon fiber itself.

As a method for producing carbon fiber from a precursor, a method in which the precursor is converted to a flame-resistant fiber in an oxidizing atmosphere at 250 to 300 ° C., followed by carbonization in an inert atmosphere at 300 to 2000 ° C. is there. In these high heat baking processes, there is a problem in that fusion of single fibers occurs and the quality and quality of the obtained carbon fibers are deteriorated. In order to prevent this fusion, many technologies have been proposed for imparting a precursor with a silicone-based oil agent having excellent heat resistance, in particular, an amino-modified silicone-based oil agent that can further improve heat resistance by a crosslinking reaction (see Patent Documents 1 to 3). Widely used industrially.
JP-A-6-220722 Japanese Patent Laid-Open No. 11-117128 JP 2004-149983 A

The amino-modified silicone-based oil agent forms a non-flowable film on the single fiber by performing a three-dimensional crosslinking reaction. This prevents the fusion of single fibers in the firing process, and also prevents oxygenation in the flame resistance process by sufficiently supplying oxygen into the yarn bundle due to its excellent gas permeability. Enables the production of high quality and high quality carbon fiber. Therefore, the crosslinkability during firing is an indispensable characteristic for improving the performance of carbon fibers. However, on the other hand, in the stage of yarn production before firing, it is preferable that the amount of oil removal to the rollers and guides after application of the oil agent, particularly the heating agent, and the gumming up by crosslinking are small in order to perform smooth continuous operation. In other words, the high performance of the carbon fiber and the spinning operability resulting from the crosslinkability of the amino-modified silicone are contradictory properties, and the oil agent formulation is currently selected in consideration of the balance. There was a limit to the improvement of carbon fiber performance.

In view of the conventional technical background, an object of the present invention is to provide a precursor oil suitable for achieving both high-performance carbon fiber and stable yarn operability.

In order to solve the above-mentioned problems, the present inventors have intensively studied the amino-modified silicone oil composition, and as a result, found that the above-mentioned problems can be solved by allowing a specific compound to coexist with the amino-modified silicone. .

That is, the present invention contains 50% by weight or more of an amino-modified silicone having a viscosity at 25 ° C. of 500 mm 2 / s or more in a pure oil agent, and contains a polyoxyethylene / polyoxypropylene copolymer and / or a derivative thereof as pure It is an acrylic fiber oil agent for carbon fiber production containing 5 to 20% by weight in a minute. The amino content of the amino-modified silicone is preferably in the range of 0.15 to 3.5% by weight, and the molecular weight of the polyoxyethylene / polyoxypropylene copolymer is preferably 5000 or more.
The manufacturing method of the acrylic fiber for carbon fiber manufacture of this invention provides 0.1 to 2.0 weight% of said oil agent with respect to the acrylic fiber for carbon fiber manufacture, It is characterized by the above-mentioned.

The precursor oil of the present invention comprises amino-modified silicone and a polyoxyethylene / polyoxypropylene copolymer as essential components. In the amino-modified silicone, the amino group, which is a modifying group, is combined with radically decomposed oxygen by thermal energy to form a peroxide, and is combined with other amino groups to form a three-dimensional cross-link. Therefore, this reaction is more accelerated in the presence of radicals. On the other hand, in the polyoxyethylene / polyoxypropylene copolymer, the polyoxypropylene group is more easily decomposed by thermal energy than the polyoxyethylene group, and a radical is easily generated. Therefore, compared with amino-modified silicone alone, the crosslinking reaction by heat is more likely to proceed in the presence of polyoxyethylene / polyoxypropylene copolymer, and the heat resistance as an oil agent is improved. Carbon fiber can improve performance.

BEST MODE FOR CARRYING OUT THE INVENTION

アミノ変性シリコーンの架橋性は、アミノ基の数に大きく左右される。アミノ含有量が０．１５％を下回ると、架橋点が少な過ぎる為、本発明のポリオキシエチレン／ポリオキシプロピレン共重合体存在下においても架橋性に乏しく、耐熱性の向上が得られない。又、アミノ含有量が３．５％を上回ると、架橋性が強過ぎる為製糸操業性が低くなる。アミノ含有量が０．１５〜３．５％の範囲で本発明の効果が得られるが、架橋性と製糸操業性のバランスから０．３〜１．５％が好ましく、０．４〜１．２％がさらに好ましい。又、変性基であるアミノ基は主鎖であるシリコーンの側鎖に変性されていても良いし、末端に変性されていても良いし、又両者が変性されていても良い。尚、アミノ変性シリコーンは全油剤純分中に５０重量％以上含まれている事が好ましく、５０重量％を下回ると、架橋時の耐熱性が低くなる事がある。


The amino-modified silicone used in the present invention needs to have a viscosity at 25 ° C. of 500 mm ² / s or more in order to obtain the above-mentioned crosslinking characteristics. When the viscosity is less than 500 mm ² / s, it is inconvenient because the silicone scatters before crosslinking when heating the oil. On the other hand, the upper limit of the viscosity is not particularly limited, but if it is too high, gum-up may increase in the spinning process. Therefore, the viscosity at 25 ° C. is preferably 500 to 20,000 mm ² / s, and 1,000. More preferably, it is -10,000 mm < ² > / s. The amino content described in the present invention is defined by:
Amino content:% of NH ₂ in 1g of sample

The crosslinkability of the amino-modified silicone greatly depends on the number of amino groups. When the amino content is less than 0.15%, the number of crosslinking points is too small, so that the crosslinking property is poor even in the presence of the polyoxyethylene / polyoxypropylene copolymer of the present invention, and the heat resistance cannot be improved. On the other hand, if the amino content exceeds 3.5%, the crosslinkability is too strong, and the yarn maneuverability becomes low. The effect of the present invention can be obtained when the amino content is in the range of 0.15 to 3.5 %. 2% is more preferable. In addition, the amino group that is a modifying group may be modified to the side chain of the silicone that is the main chain, may be modified to the terminal, or both may be modified. In addition, it is preferable that the amino-modified silicone is contained in an amount of 50% by weight or more in the pure oil, and if it is less than 50% by weight, the heat resistance at the time of crosslinking may be lowered.

In the polyoxyethylene / polyoxypropylene copolymer used in the present invention, the ratio of ethylene oxide and propylene oxide which are monomer units is not particularly limited, and the unit may be either random or block. Moreover, the derivative | guide_body which added the alkyl group etc. to the terminal group can also be used as the derivative | guide_body. The molecular weight is preferably 5000 or more from the viewpoint of preventing scattering in the drying heat treatment in the yarn production process. The polyoxyethylene / polyoxypropylene copolymer is preferably contained in an amount of 5 to 20% by weight in the total pure oil. If it is less than 5%, it is difficult to obtain the effect of improving the cross-linking property of the present invention, and if it exceeds 20%, the heat resistance is lowered due to decomposition and scattering of the polyoxyethylene / polyoxypropylene copolymer.

The oil agent of the present invention is only required to contain the amino-modified silicone and the polyoxyethylene / polyoxypropylene copolymer in the above ratio, and an antioxidant, an antistatic agent, a viscosity as long as the performance is not impaired. An additive such as a reducing agent or penetrating agent may be contained, but one that does not inhibit the silicone crosslinking reaction is selected. When the oil agent of the present invention is applied to the precursor, it may be applied at any stage of the yarn making process. That is, it may be applied immediately after spinning, may be applied after stretching, or may be applied at the winding stage. With respect to the application method, it may be applied by a roller or the like as a straight oil consisting only of a pure oil agent, or may be emulsified or dispersed in a solvent such as water, and oiled by an immersion method, a spray method or the like. In the latter case, an appropriate surfactant may be used as an emulsifier, particularly when emulsified or dispersed in water. In some cases, an essential component polyoxyethylene / polyoxypropylene copolymer may be used as a part of the emulsifier. The amount of the oil agent applied to the precursor is appropriately selected depending on its effect, but is preferably 0.1 to 2.0% by weight, more preferably 0.5 to 1.5% by weight as a pure component.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, it is not limited to the Example described here. In addition, the percentage% shown by the following example shows weight%, unless specifically limited. Each characteristic value was measured based on the following method.

<Oil agent adhesion amount> The precursor after application of the oil agent is alkali-melted with potassium hydroxide / sodium butyrate, dissolved in water, and adjusted to pH 1 with hydrochloric acid. This is colored by adding sodium sulfite and ammonium molybdate, and colorimetric determination (wavelength 815 mμ) of silicomolybdenum blue is performed to determine the silicon content. The oil adhesion amount in the sample is calculated using the silicon content obtained here and the value of the silicon content in the oil obtained in advance by the same method.

<Spinning operability (roller dirt)> The degree of contamination (gum-up) of the drying roller after applying the oil to 50 kg of the precursor was determined by the following index.
○: Roller contamination due to gum-up is low and there is no problem with thread-manufacturing. : Roller contamination due to gum-up is remarkable, single yarn is taken out during yarn making, and there is a string

<Oil agent heat resistance (heat loss)> 1 g of each oil agent emulsion was collected on an aluminum cup having a diameter of 60 mm and treated with a hot air dryer at 105 ° C. for 3 hours to remove moisture. The obtained sample was heat-treated in a gear oven at 250 ° C. for 1 hour. The oil agent loss after heat treatment relative to the amount of oil agent before heat treatment was measured to evaluate the oil agent heat resistance.

<Fusing prevention> Short fibers having a length of 10 mm were cut out from 20 random locations in the carbon fiber, and the fused state was observed and determined by the following index.
◎: No fusion ○: Almost no fusion △: Less fusion ×: Many fusion

<Carbon fiber strength> Measurement was performed according to the epoxy resin impregnated strand method defined in JIS-R-7601, and the average value of 10 measurements was defined as carbon fiber strength.

Amino-modified silicone S-1 (25 ° C. viscosity: 1300 mm 2 / s, amino content: 0.9%): polyoxyethylene / polyoxypropylene block copolymer P-1 (ethylene oxide: polypropylene oxide = 80: 20, Molecular weight: 15000): Nonionic emulsifier 1 (polyoxyethylene 7 mol added alkyl (C12-14) ether = Oil agent composition having a ratio of 86: 5: 9, an oil agent emulsion was obtained by a known phase inversion emulsification method. This was applied to a precursor of a precursor (0.8 dtex, 24,000 filament) at a target adhesion amount of 1.0%, and dried to remove moisture at 100 to 140 ° C. The precursor was put into a 250 ° C. flameproofing furnace. In a carbonization furnace having a temperature gradient of 300 to 1400 ° C. under a nitrogen atmosphere. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-1: Nonionic emulsifier 1 = An oil agent composition having a ratio of 83: 10: 7 In the same manner as in Example 1, a precursor and carbon fiber were used. Obtained. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-1: Nonionic emulsifier 1 = Oil agent composition having a ratio of 74: 20: 6 Obtained. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-2 (ethylene oxide: polypropylene oxide = 70: 30, molecular weight: 11000): nonionic emulsifier 1 = 83: 10: 7 About the oil agent composition, a precursor and carbon fiber were obtained in the same manner as in Example 1. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene random copolymer P-3 (ethylene oxide: polypropylene oxide = 75: 25, molecular weight: 15000): nonionic emulsifier 1 = 83: 10: 7 About the oil agent composition, a precursor and carbon fiber were obtained in the same manner as in Example 1. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-4 (ethylene oxide: polypropylene oxide = 85: 15, molecular weight: 5000): nonionic emulsifier 1 = 83: 10: 7 About the oil agent composition, a precursor and carbon fiber were obtained in the same manner as in Example 1. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer derivative P-5 (ethylene oxide: polypropylene oxide = 80: 20, molecular weight: 5000, addition of alkyl (C18) group at the terminal): nonionic emulsifier 1 A precursor and carbon fiber were obtained in the same manner as in Example 1 for an oil agent composition having a ratio of 83: 10: 7. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-2 (25 ° C. viscosity: 3800 mm2 / s, amino content: 0.4%): polyoxyethylene / polyoxypropylene block copolymer P-1: nonionic emulsifier 1 = 83: 10: 7 About the oil agent composition which consists of a ratio, the precursor and carbon fiber were obtained like Example 1. FIG. Table 5 shows the evaluation results of each characteristic value.

Amino-modified silicone S-3 (25 ° C. viscosity: 5000 mm2 / s, amino content: 0.2%): polyoxyethylene / polyoxypropylene block copolymer P-1: nonionic emulsifier 1 = 83: 10: 7 About the oil agent composition which consists of a ratio, the precursor and carbon fiber were obtained like Example 1. FIG. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 1

A precursor and carbon fiber were obtained in the same manner as in Example 1 for an oil agent composition having a ratio of amino-modified silicone S-1: nonionic emulsifier 1 = 91: 9. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 2

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-6 (ethylene oxide: polypropylene oxide = 75: 25, molecular weight: 2000): nonionic emulsifier 1 = 83: 10: 7 About the oil agent composition, a precursor and carbon fiber were obtained in the same manner as in Example 1. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 3

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-7 (ethylene oxide: polypropylene oxide = 40: 60, molecular weight: 2900): nonionic emulsifier 1 = 83: 10: 7 About the oil agent composition, a precursor and carbon fiber were obtained in the same manner as in Example 1. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 4

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-1: Nonionic emulsifier 1 = For an oil agent composition having a ratio of 88: 3: 9, a precursor and carbon fiber were added in the same manner as in Example 1. Obtained. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 5

Amino-modified silicone S-1: Polyoxyethylene / polyoxypropylene block copolymer P-1: Nonionic emulsifier 1 = An oil composition having a ratio of 68: 25: 7 In the same manner as in Example 1, a precursor and carbon fiber were used. Obtained. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 6

Amino-modified silicone S-4 (viscosity at 25 ° C .: 1200 mm2 / s, amino content: 3.2%): non-emulsifier 1 = 91: 9 ratio of oil agent composition as in Example 1, precursor, carbon fiber Got. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 7

Amino-modified silicone S-5 (25 ° C. viscosity: 3000 mm2 / s, amino content: 0.13%): nonionic emulsifier 1 = 91: 9 ratio of oil agent composition as in Example 1, precursor, carbon fiber Got. Table 5 shows the evaluation results of each characteristic value.

Comparative Example 8

Amino-modified silicone S-5: Polyoxyethylene / polyoxypropylene block copolymer P-1: Nonionic emulsifier 1 = An oil agent composition having a ratio of 83: 10: 7 In the same manner as in Example 1, a precursor and carbon fiber were used. Obtained. Table 5 shows the evaluation results of each characteristic value.

As is clear from Table 5, the examples are superior in yarn maneuverability and have a small loss on heating, that is, excellent in crosslinkability, and the obtained carbon fiber strength is improved. I understand.

The contents of amino-modified silicones and polyoxyethylene / polyoxypropylene copolymers used in Examples and Comparative Examples are summarized in Tables 1 and 2, and the contents of the oil composition are summarized in Tables 3 and 4. did.

The invention's effect

With the acrylic fiber oil agent for producing carbon fiber of the present invention, carbon fiber with little gum-up in the spinning process, excellent operability and high carbon fiber strength due to its high heat resistance can be produced.

Claims (3)

50% by weight or more of amino-modified silicone having a viscosity at 25 ° C. of 500 mm ² / s or more is contained in the pure oil, and 5% of the polyoxyethylene / polyoxypropylene copolymer and / or its derivative is contained in the pure oil. Contains ~ 20 wt% ,
The amino content of the amino-modified silicone is in the range of 0.15 to 3.5% by weight;
An acrylic fiber oil agent for producing carbon fibers , wherein the polyoxyethylene / polyoxypropylene copolymer has a molecular weight of 5000 or more . The manufacturing method of the acrylic fiber for carbon fiber manufacture characterized by providing 0.1 to 2.0weight% of the oil agent of Claim 1 with respect to the acrylic fiber for carbon fiber manufacture. The manufacturing method of the carbon fiber which provides the oil agent of Claim 1 to the acrylic fiber for carbon fiber manufacture, flame-treats the acrylic fiber for carbon fiber manufacture to which this oil agent was provided, and then carbonizes.