JPS58120819A - Oiling agent for fiber for preparing carbon fiber - Google Patents

Abstract

PURPOSE:An oiling agent for precursors capable of giving carbon fibers having high quality and performance without sticking between fibers, fluffs nor generating broken fibers, consisting of an oiling agent of a higher alcohol or a higher fatty acid having a specific number of carbon atoms and an organic antioxidant, and having improved heat resistance. CONSTITUTION:An oiling agent, consisting of an oiling agent of a >=18C higher alcohol and/or a higher fatty acid and an organic antioxidant, e.g. 4,4'-butylidene-bis(3-methyl-6-tert-butylphenol), and having at least 200 deg.C upper limit of heat resistance expressed in terms of a temperature measured by collecting 10mg, based on the solid, oiling agent in a thermobalance apparatus, heating the oiling agent at 2.5 deg.C/min heating rate, and determining the temperature from the resultant weight loss curve when the weight loss is 5wt% based on the weight of the oiling agent (solid). The oiling agent is applied to acrylic fibers, etc. and the oiled acrylic fibers are then passed through the flameproofing and carbonizing steps to give the aimed carbon fibers having high quality and performance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil agent applied to raw fibers for producing carbon fibers such as rayon, acrylic fibers, and pitch fibers.

Due to its excellent physical and chemical properties, carbon fiber is used to reinforce so-called composite materials in many applications such as aircraft, spacecraft, submarine immersion pressure vessels, and sports equipment such as golf shafts, tennis rackets, and fishing rods. It is produced and used in large quantities as a fiber.

Typical fiber materials, precursors, that are raw materials for producing carbon fibers include bistooth fibers, acrylic fibers, and pitch-based fibers, but these precursors are generally heated at temperatures of at least 200°C in an oxidizing atmosphere. It is well known that carbon fibers are converted into carbon fibers through a process of making them flameproof or infusible in an atmosphere of elevated temperature and then carbonizing them at a high temperature of at least 800'C in an inert atmosphere. The precursor, which is made flameproof or infusible under such harsh conditions and then carbonized and graphitized, undergoes these high-temperature heat treatments, especially during the process of making it flameproof or infusible. This causes problems such as fuzz and thread breakage due to the occurrence of mechanical defects on the surface.
It is not always easy to manufacture carbon fibers with constant quality and performance with good productivity.

Problems or problems inherent in the production of such carbon fibers
In order to solve this problem, many proposals have been made regarding the composition of the raw materials (polymer composition, pitch composition, etc.) that make up the fibers that are the raw materials for producing carbon fibers, as well as the chemical and oil treatment of the precursor. Regarding the precursor oil, it is not only related to troubles and problems in the process of converting the precursor into carbon fiber, but also the precursor, that is, the yarn oil, affects the productivity, process stability, quality, and performance of the yarn itself. The oil agent is selected by taking into account only the troubles or side effects in the conversion to carbon fiber, which are directly related to the above.

The problem is that it cannot be applied.

For example, as a representative example, organopolysiloxane is used for manufacturing carbon fibers, although it is unique as a raw fiber oil agent. It is disclosed that it is effective in preventing fusion, fluffing, and thread breakage in making acrylic fibers flame resistant. However, this organopolysiloxane becomes a silicate and firmly adheres to guides, rollers, etc. during the flameproofing and carbonization process, not only contaminating the manufacturing equipment but also causing silicon compounds in the waste gas generated from the flameproofing and carbonization process. It accumulates and adheres to the inner walls of pipes during waste gas treatment, making maintenance and management of firing equipment and waste gas processing equipment extremely complicated, and the operation of carbon fiber manufacturing equipment has to be suspended for a long period of time. This causes production problems such as
It has serious disadvantages in practical use as a lubricant for yarn used in carbon fiber production.

The present inventors have developed a high-quality yarn with 2 fluffs fused between single yarns and no yarn breakage.
The present invention was discovered through extensive research into precursor oils for producing high-performance carbon fibers. That is, the purpose of the present invention is not only to use as a process lubricant for raw yarn for carbon fiber production, but also to make the raw yarn flame resistant or non-flammable. The purpose of the present invention is to provide a raw yarn lubricant that prevents fusion between single yarns in the process of carbonization or carbonization, and does not leave any residue as tar on the surfaces of guides, rollers, and fibers. In particular, it is an object of the present invention to provide a fiber oil agent that improves the density of acrylic fiber fibers and, as a result, increases the strength of carbon fibers.

As described in the claims, the object of the present invention is to provide a heat-resistant oil containing a higher alcohol-based and/or higher fatty acid-based oil having at least 18 carbon atoms and an organic antioxidant. This can be achieved by using a raw fiber oil for producing carbon fibers whose temperature is at least 200°C.

The raw yarn for carbon fiber production is subjected to a high temperature heating atmosphere of at least 200°C during the flame-retardant or infusible process, and by heating at this high temperature, the raw yarn undergoes complex processes such as intermolecular cross-linking and molecular circularization. It is converted into flame-resistant or infusible fiber through a chemical reaction, but in this case, the raw fiber is softened at the initial stage of heating.

It is unavoidable that partial melting and tar formation as the reaction progresses causes fusion between the single filaments and the formation of defects in the fibers. The occurrence of inter-fiber bonding and fiber defects during the initial high-temperature heating of raw yarn varies markedly depending on the type of oil attached to the raw yarn.
When volatilization and thermal decomposition occur at a lower temperature, it is not expected to be effective in preventing such fusion or fiber defects, and on the contrary, it may have a negative effect.

In the present invention, when the main components of the oil agent are composed of a higher alcohol-based and/or higher fatty acid-based oil agent and an organic antioxidant, and the heat resistance is at least 200°C, carbon fiber production is possible. It has excellent performance as a raw material oil, especially as a process oil for acrylic fibers, and is extremely effective in preventing troubles caused by the oils mentioned above.

Higher alcohols and/or the main components of the oil of the present invention
Alternatively, if the number of carbon atoms in a higher fatty acid-based oil is less than 18, the oil will penetrate into the fibers significantly, reducing the adhesion prevention effect and causing a decrease in the physical properties of the carbon fiber assembly, especially the occurrence of defects in the carbon fibers. The number of carbon atoms should be at least 18, preferably 18 to 25, since this may be a cause of carbon atoms.

Examples of such oils of the present invention include stearyl alcohol phosphate ester salts and ethylene oxide ((EO)n) as higher alcohol oils.
Stearyl alcohol (KO) n having a number of about 20 to 40.

Oleyl alcohol (EO) n, behenyl alcohol (KO) n, isopentacosanyl alcohol (B20)
” etc., but stearyl alcohol (KO)
Preferably used are oleyl alcohol (K 2 O) n, inpentacosanyl alcohol (EO) n, and the like.

Two or more of these oil agents may be used in combination. In addition, examples of higher fatty acid oils include stearic acid glyceride and polyethylene glycol (PEG).
) with a molecular weight of 400 to 1000, PEG stearate, PEG oleate, PEG sorbitan ole), PE
Examples include G-sorbitan stearate, but especially PE
G stearley 1-, PEG oleate, etc. are preferably used. Note that two or more of these oil agents may be used in combination.

Furthermore, the heat resistance of typical higher alcohol-based oils and higher fatty acid-based oils is shown in Table 1.

Here, heat resistance refers to the temperature increase of 2.5°C/min when 101 of the solid content of the oil is sampled on a thermobalance device. This is the temperature at which the weight loss rate based on the weight of the oil agent (solid content) is 5% from the weight loss curve obtained when heating at 7 degrees.

Next, the organic antioxidant to be used in combination with the higher alcohol-based and higher fatty acid-based oils must be compatible with the higher alcohol-based and higher fatty acid-based oils, and have a heat resistance of at least 200°C. By increasing the temperature, it can withstand the initial heating to make the yarn flame resistant or infusible, and at the same time, it can easily be thermally decomposed and volatilized during the flame resistance or infusibility of the yarn, and will not remain in the yarn as a residual residue. is necessary.

Examples of such antioxidants include 4. ．． 4'-Butylidene-bis(3-methyl-6-tert-butylphenol)
, 4,4'-thio-bis(3-methyl-6-tert-butylphenol), bis(2,26,6-tetramethyl-4
-piperidine) sebacate, tetrakis[methylene-3
(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, di(nonylphenyl)dinonylphenyl phosphite, etc. are preferably used,
A mixture of two or more types can also be used.

In addition, the amount of antioxidant added to the higher alcohol-based and/or higher fatty acid-based oil is 1 to 20 per 80 to 99% by weight of the oil, and the thermal effect is insufficient.
If it exceeds 20%, the antioxidant may remain as a heating residue in the flame-resistant or infusible resin fibers or the carbonized or graphitized fibers, which is not preferable.

The yarn oil of the present invention comprises the above-mentioned higher alcohol and/or
or consisting of a higher fatty acid oil and an organic antioxidant,
It is necessary that this raw fiber oil has a heat resistance of at least 200°C, and if it is insufficient to 200°C, flame-resistant fibers,
A decline in the physical properties of carbonized fibers is unavoidable. The heat resistance of the yarn oil agent of the present invention is usually 200 to 300°C.

The uniformity of adhesion is the same as when the antioxidant is used in combination, that is, when only the higher alcohol-based and/or higher fatty acid-based oil of the present invention is used. However, the above-mentioned raw yarn oil agent has the characteristic that it is easy to separate the single yarns after adhesion treatment and drying treatment to the precursor, that is, it prevents the occurrence of adhesion, and this is due to the flame resistance, infusibility, or carbonization process. This has the effect of helping to reduce the occurrence of fusion.

The raw material oil of the present invention easily thermally decomposes and volatilizes during the initial flame-retardant or infusible process, prevents the occurrence of fusion during the flame-retardant, infusible or carbonize process, and forms a tar-like substance on the guide, roller surface, or fiber surface. No food remains.

After adhering to the precursor using such a raw yarn oil, the heat-treated carbon fiber has no fuzz, no thread breakage, high strength, and little variation in strength. . Further, normal processing conditions can be used for operability 2, for example, compatibility with resin when making a composite material.

Various known oil preparation methods are applied to prepare the raw yarn oil. For example, if the higher alcohol-based or higher fatty acid-based oil is a solid oil, it is heated to about 40 to 70°C for 1 hour to make it liquid, and then stirred. At the same time, an antioxidant is added to this.

If the oil is in liquid form, add the antioxidant while stirring. When the oil consists of a higher alcohol-based oil and a higher fatty acid-based oil (if solid, it has a
℃), mix and stir, and add the antioxidant while continuing to stir. Next, while stirring hot water of about 40 to 70°C, the antioxidant-containing oil agent is added to the warm water to prepare the aqueous solution. A conventional method is used for adhesion treatment to the precursor, and the amount used is usually in the range of about 1 to 3% based on the weight of the fiber, but higher alcohol-based oils, higher fatty acid-based oils, and organic antioxidants are used. The amount of adhesion is not limited depending on the type, etc.

The raw material lubricant for carbon fiber production according to the present invention not only has excellent performance as a process lubricant in the production of carbon fibers, particularly in the production of acrylic fibers, but also has the following properties: This prevents tar-like substances from sticking to the surfaces of guides, rollers, and fibers, and can be manufactured with high productivity.

It also has remarkable effects, such as the ability to obtain high-strength carbon fibers.

The present invention will be specifically described below with reference to Examples.

Example 1 Acrylonitrile 9907%, allylsulfonic acid sodium 05%, 2-hydroxyethyl acrylonitrile 05%
-% was polymerized by a solution polymerization method using dimethyl sulfoxide as a solvent, and the raw g! After preparing a spinning stock solution with a concentration of 22%, it was spun into a dimethyl sulfoxide aqueous solution, washed with water and stretched by a known method to obtain a raw yarn of 3000 denier and 3000 filaments. This drawn yarn is made of stearyl alcohol (Eo)+. It was dipped at 40°C in an 85% aqueous solution of a raw fiber oil consisting of 4% by weight of di(nonylphenyl) dinonylphenyl phosphite at 95°C and dried to obtain a 61% acrylic fiber filament. The amount of oil attached was 2.0% based on the weight of the raw yarn.

Next, this raw yarn was continuously passed through a flameproofing process and a carbonization process at a yarn speed of 3 m/mln. The flame-retardant process is carried out in air.
The treatment was carried out at 0°C for 20 minutes, and the carbonization step was carried out through a carbonization furnace at 1200°C in a nitrogen atmosphere.

In addition, as Comparative Example 1, when no antioxidant was added, that is, stearyl alcohol (EOLo), O
The same procedure was carried out for 0%. The results are shown in Table 2.

Examples 2 to 8 Processing was carried out in the same manner as in Example 1, except that the blending ratio or combination type of oil agent and organic antioxidant was changed. The results are shown in Table 3.

In addition, in each of the examples, there was substantially no residual tar-like substance adhering to the surfaces of various guides and roller fibers during the flameproofing step and the swelling step.

(B)) Patent application Daitoshi Co., Ltd. (16 completed)

Claims (1)

[Scope of Claims] (]) Consists of a higher alcohol-based and/or higher fatty acid-based oil having at least 18 carbon atoms and an organic antioxidant, and has a heat resistance of at least 200 as determined by the following measuring method. Raw oil for carbon fiber production at ℃. Here, heat resistance is based on the weight of the oil (solid content) obtained from the weight loss curve obtained when 10 pieces of the oil agent as solid content are collected in a thermobalance device and heated at a temperature increase rate of 2.5°C/min. This is the temperature when the weight loss rate is 5%. (2. In claim 1, carbon fiber is produced by blending an organic antioxidant in a range of 1 to 20% by weight per 80 to 99% by weight of a higher alcohol-based and/or higher fatty acid-based oil agent. Yarn oil agent.