JPH01221579A - Oiling agent for producing carbon fiber - Google Patents

Abstract

PURPOSE:To obtain an oiling agent, consisting of an aqueous emulsion containing a specific silicone oil and aliphatic monocarboxylic acid alkanolamide as an essential emulsifying agent and capable of imparting wetting characteristics and melt sticking resistance to carbon fibers by application thereto. CONSTITUTION:An aqueous emulsion rich in long-period stability is prepared by using (A) a silicone oil (preferred example; dimethyl silicone) which is a simple substance or mixture having <=100cst viscosity at 25 deg.C as a principal component with (B) an essential emulsifying agent consisting of an 8-18C aliphatic monocarboxylic acid alkanolamide at 95-75/5-25 ratio of the components (A)/(B). This emulsion is then applied to carbon fibers during steps ranging from spinning to infusibilizing thereof to exhibit wetting characteristics, improve process passableness and impart excellent melt sticking resistance especially to the above-mentioned fibers.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a lubricant for producing carbon fibers.

Pitch-based or PAN-based carbon fibers are widely used to improve the performance, such as the strength and elastic modulus, of composite materials used in fields such as aviation, space, leisure, and sports.

However, carbon fiber is inherently very fragile.

Therefore, in the production of carbon fibers, from the time the fibers are spun until they pass through the infusibility process, an oil agent is used to bundle the fibers and improve their processability.

In recent years, demands for improving the performance of composite materials have become more sophisticated, and increasingly higher demands have also been placed on the performance of carbon fibers used in such composite materials. Naturally, there is a strong demand for oils that have a great effect on the performance of carbon fibers to have a high level of performance.

The present invention relates to a lubricant for producing carbon fibers that meets the above requirements.

<Prior art and its problems> Conventionally, in the production of carbon fibers, silicone-based compounds have been known as oil components that have inter-fiber fusion resistance, fiber cohesiveness, lubricity, etc. -12375,
Japanese Patent Publication No. 47-36464, Japanese Patent Publication No. 49-117724,
JP-A-59-223315). Of these, most of the actually effective ones are hydrophobic silicone compounds.

Therefore these hydrophobic silicone compounds.

It is used as a solution in an organic solvent or as an aqueous emulsion.

However, oil agents used in organic solvent solutions are because the organic solvent dissolves the fibers, albeit to varying degrees.

Problems such as fusion cannot be avoided, and there is also a risk of ignition or explosion.

On the other hand, the oils used in aqueous emulsions are poor in terms of workability and safety, and there are various proposals regarding the emulsifiers used in combination and their ratios (Japanese Patent Laid-Open No. 60-18
1322, JP-A-60-181323, JP-A-61-7
0017. JP-A-62-156316).

However, the above-mentioned conventional oils used in aqueous emulsions are difficult to obtain in terms of obtaining a stable silicone emulsion, uniformly adhering the emulsion to fibers, and especially preventing fusion between fibers. However, there is a problem in that it cannot meet the advanced demands of recent years.

<Problems to be Solved by the Invention and Means for Solving the Problems> The present invention provides an improved lubricant for producing carbon fibers that solves the conventional problems as described above.

However, as a result of intensive research from the above viewpoint, the present inventors found that
We obtained the following meaningful findings.

First, when conventional silicone emulsions are used for carbon fibers, especially when used for pitch-based carbon fibers, the excellent resistance of silicone, which is the main component, is lost even though the emulsifier that emulsifies the silicone is a secondary component. Significantly impeding fusion performance.

Second, the material of the oil supply roller and oil supply guide used to attach the silicone emulsion to the fibers is usually metal or ceramic, but conventional silicone emulsions have poor wettability with these materials, or At best, the silicone emulsion has the disadvantage that it becomes water-repellent over time, resulting in poor wetting, and this is a major obstacle to uniformly adhering the silicone emulsion to the fibers.

Emulsifiers used in conventional silicone emulsions include polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester,
There are polyoxyethylene lanolin derivatives, alkyl sulfate esters, dialkyl sulfosuccinates, etc., but when polyoxyalkylene addition type emulsifiers are used for silicone in China and Germany, fusion between fibers occurs under heating conditions of 200 to 300°C. Also, when emulsifiers such as sorbitan fatty acid esters, alkyl sulfate esters, dialkyl sulfosuccinates, etc. are used, they will turn into tar considerably under heating conditions of 200 to 300°C, and eventually the fusion between fibers will occur. to become remarkable.

Therefore, the inventors investigated further and found that an aqueous emulsion containing a specific silicone oil as a main component and a specific alkanolamide or a combination of the alkanolamide and a specific amine salt as an essential emulsifier is correct and suitable. They discovered something and completed the present invention.

That is, the present invention consists of a silicone oil as a main component, which is either a single substance or a mixture, and has a viscosity of 100 centistokes or less at 25°C, and contains a carboxylic acid having 8 to 18 carbon atoms as an essential emulsifier. Certain aliphatic monocarboxylic acid alkanolamides or in addition to the alkanolamides, carbon atoms of 8 to
The present invention relates to an oil agent for producing carbon fibers, which basically consists of an aqueous emulsion containing an amine salt of No. 18 aliphatic monocarboxylic acid.

In the present invention, the silicone oil that is the main component of the oil agent is a hydrophobic silicone having a viscosity (viscosity at 25° C., the same applies hereinafter) of 100 centistokes or less. Among these, dimethyl silicone, phenyl-modified silicone, and amino-modified silicone are particularly preferred. The viscosity is l
When OO centistokes are exceeded, it is difficult to obtain an aqueous emulsion that is stable for a long time.

In the present invention, the aliphatic monocarboxylic acid alkanolamide may be natural or synthetic, saturated or unsaturated, linear or Regardless of whether it has a side chain, an aliphatic monocarboxylic acid having 8 to 18 carbon atoms or a lower alkyl ester thereof, such as monoethanolamine,
one or more of jetanolamine, monoisopropanolamine, diisopropanolamine, and 1/
The reaction was carried out at a molar ratio of 1 to 1/2. If the carboxylic acid is an aliphatic monocarboxylic acid alkanolamide having less than 8 carbon atoms or more than 18 carbon atoms, the resulting aqueous emulsion will lack stability and wetting properties.

Furthermore, in the present invention, the aliphatic monocarboxylic acid that is the raw material for the amine salt of an aliphatic monocarboxylic acid, whether it is natural or synthetic, saturated or unsaturated. , is an aliphatic monocarboxylic acid having 8 to 18 carbon atoms, regardless of whether it is linear or has a side chain. Among these, aliphatic monocarboxylic acids having 8 to 10 carbon atoms are particularly preferred; if the number of carbon atoms is less than 8 or more than 18, the resulting aqueous emulsion will lack stability and wetting properties. As the amine serving as a counter ion for the above aliphatic monocarboxylic acid, lower alkyl amines and alkanolamines can be used. Specifically, trimethylamine, triethylamine, dimethylaminopropylamine, morpholine, monoethanolamine, jetanolamine, triethanolamine.

Examples include monoisopropanolamine, diisopropanolamine, triisopropanolamine, butylgetanolamine, dibutylethanolamine, aminoethylethanolamine, and alkanolamines are particularly preferred.

The oil agent according to the present invention can be made stable by mixing silicone oil and an emulsifier as previously explained, gradually adding water at room temperature to the mixture to form a rough emulsion, and providing the rough emulsion to a homogenizer. It can be obtained as an aqueous emulsion. In this case, the weight ratio of silicone oil and emulsifier is silicone oil/emulsifier; 95-7515-
It is preferable to set it to 25. When the weight ratio is within the above range, a more stable aqueous emulsion can be obtained, and an aqueous emulsion with better fusion resistance can be obtained. The concentration of the aqueous emulsion thus prepared can be in the range of 0.1 to 65% by weight, but it is usually prepared in the range of 5 to 65% by weight, and in actual use it is 1 to 20% by weight. It is preferable to dilute to a range of .

If necessary, other conventionally known emulsifiers, antistatic agents, rust preventives, antibacterial agents, etc. may be used in combination.

Hereinafter, in order to make the configuration and effects of the present invention more specific,
Examples will be given, but the present invention is not limited to these examples.

<Example> - Test category 1 Dimethyl silicone 30 with a viscosity of 20 centistokes
(parts by weight, same hereinafter) and 3 parts of lauric acid jetanolamide (high temperature dehydration condensation product of 1 mole of lauric acid and 2 moles of jetanolamine), 67 parts of water at room temperature was gradually stirred. In addition, a crude emulsion was obtained. This was subjected to a homogenizer to prepare a stable aqueous emulsion with a concentration of 33% by weight (Example 1). Similarly, from 30 parts of dimethyl silicone having a viscosity of 10 centistokes, 3 parts of coconut fatty acid diisopropanolamide, 4 parts of dinitanolamine decanoate salt and 63 parts of water, a concentration of 37% by weight was prepared.
Aqueous emulsions were prepared (Example 2). 18 kg of each aqueous emulsion was placed in a 20-liter container and allowed to stand at 20° C. for 6 months, but no creaming or separation phenomenon was observed in either case. Table 1 shows the measurement results of particle diameters of each aqueous emulsion by centrifugal sedimentation.

Table 1 - Test Category 2 The aqueous emulsions listed in Table 2 were prepared in the same manner as in Test Category 1, and the wetting properties of each aqueous emulsion were evaluated in the following manner. The results are shown in Table 3.

...Evaluation of wetting characteristics Fill a roller-type oiling device equipped with a magnetic roller with an amount of each water-based emuldigon so that part of the roller is immersed.
The roller was left to rotate, and the water repellent phenomenon on the roller surface was observed over time, and evaluated using the following criteria.

O: No water-repellent phenomenon Δ: Slight water-repellent phenomenon ×: Water-repellent phenomenon The emulsion was evaluated for wetting properties using the method described above, and for fusing resistance of pitch fibers using the following method. The results are shown in Table 5.

...Evaluation of fusion resistance A pitch fiber bundle consisting of 500 filaments cut to a length of 2 cm was immersed in each aqueous emulsion with a concentration of 1% by weight, placed on a wire mesh, and heated at 25°C x 65%. R.H.
After air drying overnight in an atmosphere of After the heat treatment, the fiber bundle was transferred onto a filter paper and loosened by hand.The state of defibration of the fiber bundle was observed and evaluated based on the criteria in f.

O: The filament was defibrated into a monofilament.O: There was very slight fusion of a few filaments, but the rest was defibrated into a monofilament.Δ: There was a lot of fusion of several tens of filaments. There are only a few fibrillated fibers in the form of monofilaments. ×: Most of the fibers are tens or more or are fused as original fiber bundles, and there are no fibrillated fibers in the form of monofilaments. Table 4 71) A-1 : Dimethyl silicone (viscosity 5 centistokes) A-2: i combined dimethyl silicone (viscosity 15 centistokes = 107 centistokes + 10 centistokes)
00 c) Stokes) A-3: Phenyl modified silicone f viscosity 20 cs) A-4 = 7 mino modified silicone (viscosity 80 cs) A-5:
Dimethyl silicone (viscosity 200 centistokes)
B-1: Oleic acid gedano h7 mido B-2:
Lauric acid jetanolamide B-3: Lauric acid monoethanol 7mide 4: Lauric acid diisopropanolamide B-5: Hexadiate jetanol amide B-6: Erucic acid jetanolamide D-1
= Polyoxyethylene (8 mol) nonyl phenyl ether Table 5, Test Category 4 In the same manner as in Test Category 1, the aqueous emulsions listed in Table 6 were manufactured by Ji, and each aqueous emulsion (1st batch) was prepared. The wetting properties and the fusion resistance of the pitch fibers were evaluated using the methods described above. The results are shown in Table 7.

Table 6 Note) A-8: Dimethyl silico-) (viscosity: 10 sec) A-7: Butnyl modified silico-(viscosity [10 Qt: + nas stokes)] B-7: Coconut fatty acid jetanol 7-mide (during reaction Molar ratio: Coconut fatty acid/diet 7 tannol 7 mm = tll) B-8: Coconut fat s dieta λ-h amide (molar ratio during reaction: coconut mm/diet 7 tannol 7 mm, -1/2) C-1: Triisopalmitate n? 1 mol 7 min 11XC-2: Decanoic acid triisopropanol 7 min Salt C-3 2 octane
Acid triisopro! ; Nor7mishi Monthly IC-4= Octane Acid Jetanol 7mish Salt C-52 Octane
Acid monoethanolamine salt C-6 di-octane acid dibutyl ethanol P misi salt C-7 = octane acid 7 mi J ether ethanol 7 misi salt C-8: engineered hydrochloric acid triisopropylene rs) -le 7 misi salt C-9: Triisobutylene hexadiate (6 moles) nonylphenyl ether Because it is a stable water-based emulsion, it has extremely good workability, including the fact that there is no danger of ignition or explosion.Also, the water-based emulsion is stable for a long period of time and exhibits excellent wetting properties, so it is suitable for use in carbon steel. It has the effect that it can be uniformly adhered over a long period of time, and that it can particularly impart excellent fusion resistance to carbon fibers.

Patent applicant: Takemoto Yushi Co., Ltd. Agent: Hiroshi Yama, Patent Attorney

Claims (1)

[Scope of Claims] 1. Aliphatic monocarboxylic acid, which is a single substance or a mixture, and whose main component is silicone oil having a viscosity of 100 centistokes or less at 25°C, and whose carboxylic acid has 8 to 18 carbon atoms. An oil agent for carbon fiber production consisting of an aqueous emulsion containing acid alkanolamide as an essential emulsifier. 2. An aliphatic monocarboxylic acid alkanolamide whose main component is a silicone oil which is a single substance or a mixture and has a viscosity of 100 centistokes or less at 25°C, and whose carboxylic acid has a carbon number of 8 to 18, and a carbon number 8-1
An oil agent for producing carbon fibers comprising an aqueous emulsion containing an amine salt of an aliphatic monocarboxylic acid (No. 8) as an essential emulsifier. 3. Claim 1, wherein the weight ratio of silicone oil and emulsifier is silicone oil/emulsifier=95-75/5-25.
Or the oil agent for carbon fiber production according to 2. 4. The oil agent for producing carbon fibers according to claim 1, 2 or 3, wherein the carbon fibers are pitch-based carbon fibers.