JPS6170017A - Production of pitch carbon yarn - Google Patents

Abstract

PURPOSE:To make handling of yarn such as carbonization, etc. easy, and to obtain the titled high-quality yarn having no mutual fusion of yarn, etc., by attaching water emulsion of silicone oil as a collecting agent to pitch yarn when the pitch yarn is bundled. CONSTITUTION:Firstly, raw material pitch such as coal tar pitch, etc. is subjected to melt spinning in a gaseous phase to give pitch yarn. Then, before the pitch yarn is bundled, or when the yarn is bundled, water emulsion of sili cone oil as a collecting agent is attached to the yarn in such a way that its pickup is 2-10wt%. Then, the pitch yarn subjected to bundling treatment is made infusible and carbonized, and, optionally graphitized, to give the aimed yarn. Usually, dimethylpolysiloxane, etc. is used as the silicone oil.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing charcoal-based fibers entirely from pitches such as coal-based pitch, petroleum-based pitch, and polymer calcined pitch. This method facilitates the handling of fibers and at the same time obtains high-quality carbon fibers without adhesion or fusion between K M 1m and VC.

[Prior art]

Pitch-based carbon fiber is usually produced by melt-spinning raw material pitch,
"C" is manufactured by subjecting the obtained pitch wax fibers to infusibility treatment and carbonization treatment.

Pitch-based carbon fibers have the advantage of being able to produce industrially advantageous ICs with a higher yield than polyacrylonitrile-based carbon fibers, but on the other hand, pitch fibers are extremely fragile and cannot be treated with infusible or carbonized treatments. When handling is d, $L<, these steps tend to cause the fibers to become fluffy, get wrapped around the guide rollers, and cause yarn breakage. Furthermore, during the infusibility treatment and carbonization treatment, a contact layer between the pitch fibers and a MiII layer are formed, and the surface of the resulting carbon fiber is easily damaged.

These problems are significantly different from those of polyacrylonitrile carbon fibers, which have different raw materials and manufacturing methods. That is, in the case of polyacrylonitrile-based carbon fibers, bath-melted polyacrylonitrile is The fibers are spun by an extrusion wet spinning method, in which each single fiber is spun and its surface is streaked by the liquid in the spinning bath, forming a tow shape 71 in the spinning bath.
1 [Focused. Spinning removal and subsequent 300. /l100
It is said that an effective method is to apply a layer of polyethylene glycol, polypropylene glycol, etc. as an oil agent to the surface of the tow during the carbonization process in an inert atmosphere.

[Problem that the invention seeks to solve]

However, when these oils are applied as a sizing agent for pitch fibers, disadvantages arise such as some of the pitch fibers melting, or the fibers coming into contact with each other or becoming fused and becoming rigid.

Therefore, the present inventors have previously proposed the use of silicone oil as a sizing agent as a method to solve this difficulty in bundling pitch fibers. Although this method allows for smooth focusing of pitch fibers, Depending on the operation, silicone oil may sometimes form an excessive layer, and in that case, there is no problem with the fruits and vegetables themselves, but after infusibility treatment or carbonization treatment, the tow tends to become hard, and in other cases, the JIB layer This may make it difficult to unwrap.

[Means for solving problems]

In order to solve these problems, the present inventors conducted further research and found that a method using a water emulsion of silicone oil as a sizing agent was preferable, and completed the present invention. After converging, the pitch fibers are subjected to aging treatment, carbonization treatment, and graphitization treatment if necessary. The present invention relates to a method for producing pitch-based charcoal-based fibers, which is characterized in that a water emulsion of silicone oil is attached to pitch fibers as a sizing agent.

``The present invention will be described in detail below.The raw material pitches used in the present invention include coal tar pitch, coal-based pitch such as coal liquefied product, Haratsukuda kudzu pressure steamed residual oil, vacuum distilled residual oil, or its heat-treated products, the heat content of naphtha [14 Petroleum-based pitch such as heat-treated products of raw tar, and synthetic-fat and natural side Bi
Examples include a certain molecular calcined pitch obtained by t' 4iE distillation.

Bath melt spinning of raw material pitch can be carried out in the same way as dry @fi melt spinning of ordinary synthetic fibers, and there are no restrictions.・The spinneret used has a discharge hole with a diameter of 0. / S-0,! ;Use something about the size of a parrot. The temperature of the spinneret depends on the 85 mVC of the raw material pitch, and is determined by determining the melt viscosity suitable for spinning, but is usually in the range of SO to ysoc. Providing a heat insulating tube under the spinneret is effective in stabilizing the spinning shape.

In the present invention, a water emulsion of silicone oil is applied as a sizing agent to the spun T-pitch fibers, but dimethylpolysiloxane is usually used as the specific silicone oil; Those modified by introducing groups of are also used. Specific examples include evamethylphenylpolysiloxane, alkyl phenylpolysiloxane, and other alkyl groups such as epoxy groups, ethyl and propyl groups, amide groups, carboxyl groups, alcohols, phenyl groups, and polyester groups. Those modified with ether groups of /14 or 21 or more are used. Moreover, these silicone oils may be used alone or in a mixture thereof.

A water emulsion of silicone oil is prepared by using a well-known mixing device such as a high speed mixer, a colloid mill, a homogenizer, etc. until the silicone oil is reduced to 0. /~35 times'i? % by mixing with water. When forming an emulsion, if the degree of silicone oil becomes too low to maintain a clear emulsion state, add 0.0% of the emulsifier. It is sufficient to add koS to koTLk%. The emulsifier may be a conventionally known emulsifier, and VC may be a nlubitan fatty acid ester, such as nrubitan barmitate, sorbimen stearate, polyoxyethylene rubitan fatty acid ester, polyoxyethylene rubitan caguronate, polyoxy Nonionic emulsifiers such as ethylene laurate, acetylated monoglyceride, acetylated glyceryl monostearate and polyoxyethylene lanolin derivatives, alkyl@t ester, sodium lauryl sulfate, sodium cetyl ester, dialkyl sulfosuccinate, di-λ Examples include anionic emulsifiers such as -ethylhexylsulfosuccinate (sodium salt) and cationic emulsifiers such as alkylpyridium chloride. Alternatively, solid fine particles of Shodong may be mixed into a water emulsion of silicone oil and used as a sizing agent.

As the solid particles, carbonaceous particles, inorganic oxide particles, organic salt particles, or a mixture thereof are preferably used. Specifically, graphite, carbon black, silica, calcium carbonate, titanium oxide, Merck, clay, etc. are used. ,
*Fine particles of tS barium, potassium titanate, molybdenum disulfide, etc. are used.

Methods for attaching the sizing agent to the pitch fibers include a method of spraying, a method of applying the sizing agent to H-1- and bringing it into contact, a method of immersing it. The adhesion t to the fibers is usually in the range of /-/S weight-, and a range of 0 to 10 times is particularly suitable. If the amount of adhesion is less than tS, a sufficient convergence state of the M fibers will not be maintained until spinning, and handling of the fiber bundle will be extremely difficult, resulting in damage to the fibers. Although it depends on the expansion of the oil agent, if it exceeds 75% by weight, volatilization during the infusibility treatment will be insufficient and it will remain on the fibers and inhibit the infusibility reaction. Since the low-molecular gas generated from the fibers cannot be sufficiently dispersed, the strength of the carbon fIt fibers is reduced.

A water emulsion of silicone oil is applied, and the bundled pitch fibers are subjected to infusibility treatment and carbonization treatment according to well-known methods. For example, infusibility treatment is GL, fiber!
! In an oxidizing atmosphere such as ozone, air, short dispersants, nitrogen, sulfur dioxide gas, etc., at a temperature of /30 to 360C from evening to evening.

The carbonization process is carried out by heating the fibers for 100 minutes under an atmosphere of inert gas such as nitrogen or argon.
0-2! ;00° C. for 0.5 minutes to 10 hours.

When further graphitizing treatment is performed, -5OO~J! ;
What is necessary is just to heat and hold at the temperature of 00 degreeC for 1 second to 1 hour. Yes
If necessary, a slight load or tension may be applied to the object to be treated for the purpose of preventing aggregation, deformation, etc., during the infusibility, carbonization, or graphitization treatment.

Furthermore, during the infusibility treatment, a dryer is provided just before the infusibility furnace, or the pitch fibers are held for 70 minutes to 7 hours in the first stage of the infusibility furnace to dry the pitch fibers with water. It is desirable to dry it to below -/X temperature.

〔effect〕

As detailed above, in the invention, the handling of fragile fibers is facilitated by applying a water emulsion of silicone oil at a controlled rate, and at the same time, adhesion or fusion between fibers or damage to the fiber surface occurs. Therefore, it is possible to produce pitch-based carbon aiHXMk in the form of continuous filaments with good deformation under industrially advantageous conditions.

Furthermore, since the heat treatment can be carried out uniformly and under sufficient tension, there is also the advantage that bit-type carbon fibers having excellent compatibility properties can be obtained at low cost.

〔Example〕

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Actual sequence l-datal system ow, family pitch (optical anisotropy 100 deaf mesophase pitch) 'Ik: spinning machine temperature ff, melt-spun at JJOC, resulting in a filament diameter of 10 pO pitch range fiber, The sizing agent shown in Table 1 was completely sprayed to form a layer and bundled.The bundled fibers (tow) were then held in air at tO 0 C for 30 minutes to dry. Next, from /jOC to JSO℃, the song is O+
The temperature is raised over a period of time, and after cooling, the temperature is maintained for 30 minutes to perform the infusibility treatment. After that, in argon, from room temperature to l
It took several hours and minutes to raise the temperature to reach OOC, and after that, the temperature was maintained for one hour to carry out carbonization treatment and obtain carbon fibers. The bundled state of the threads, the properties of the infusible fibers, and the state of the single fiber O-fusible layer in the carbon fibers were observed, and the tensile strength of the carbon fibers was measured, and the results are listed in Table 1.

Comparative Example /-3 In the implementation row /, using a sizing agent or adding a sizing agent layer or changing the sizing agent i was carried out by a colleague, and the results are also shown in the kAt table.

Claims (3)

[Claims] (1) A method for manufacturing pitch-based carbon fibers by melt-spinning raw pitch in a gas phase, converging pitch fibers obtained, and then subjecting them to infusibility treatment, carbonization treatment, and further graphitization treatment as necessary. A method for producing pitch-based carbon fibers, characterized in that a water emulsion of silicone oil is applied as a sizing agent to the pitch fibers during or before sizing. (2) The method according to claim 1, wherein the concentration of silicone oil in the sizing agent is 0.1 to 35% by weight. (3) The method according to claim 1 or 2, characterized in that 1 to 15% by weight of the sizing agent is attached to the fibers.