JPS63145421A - Infusiblizing method of pitch based fiber - Google Patents

Abstract

PURPOSE:To obtain an infusiblized fiber, uniformly infusiblized and having excellent physical properties, by melt spinning a pitch having 100% mesophase from petroleum based pitch and infusiblizing the pitch in a specific condition. CONSTITUTION:A petroleum based pitch is heat-treated to give a pitch containing mesophase, which is then aged, fused and enlarged in the mesophase and separated and purified to provide a pitch having 100% mesophase. The resultant pitch is melt spun and a sizing agent is added to the pitch to afford a pitch based fiber 5 of a filament which is then sent into an infusiblizing furnace. In the furnace 7, the fiber is infusiblized at the temperature of 150-250 deg.C which is not higher than softening point of the pitch bases fiber using an air as a pre-treatment while horizontally moving the fiber on rollers of several ten-hundred at constant speed and infusiblized while applying tension at 300-360 deg.C using an air containing 25-50% oxygen as a main treatment. The air in the furnace in circulated and the amount of consumed oxygen is supplied from others.

Description

[Detailed description of the invention] [Industrial application field] In the carbon fiber manufacturing process of petroleum-based pitch yarn, tension is applied to the fibers produced by melt spinning to infusible in two stages to produce infusible yarn. Regarding how to.

[Conventional technology]

As a result of the rapid growth of the aircraft, automobile, and other transportation manufacturing industries in recent years, there has been a growing demand for materials with unique and special combinations of physical properties, exhibiting extremely high % isomerism, and strong strength. There is a strong demand for materials that have characteristics of & elasticity and at the same time are inexpensive in & quantity. However, with current technology, it is not possible to supply such materials in large quantities at low cost. Research to answer this demand is into composite materials (reinforced resins)
is concentrated on manufacturing.

One of the most promising materials for use in composites is long-fiber, high-strength, high-modulus carbon fiber. This material was created when the aforementioned rapid growth of sedentary occupations was occurring.
When this long-fiber, high-strength, high-modulus carbon fiber is used in combination with a resin, it is possible to produce a composite material (reinforced resin) that exhibits properties that have never been seen anywhere else. Unfortunately, however, long-fiber, high-strength, high-modulus carbon fibers for temporary base materials are extremely expensive, and even though the reinforced resins that use them exhibit extremely outstanding properties, That W
The key point is that T5 has not been developed.

It is a well-known fact that the raw material for currently available long-fiber, high-strength, high-modulus carbon fibers is mainly polyacrylonitrile (PAN) l1m produced using a special manufacturing method. Although it has extremely excellent properties as a precursor, it is not a scale that can be recited as a precursor, and furthermore, the yield of carbon fiber from this precursor is about 45%.
% of the acrylonitrile fiber is extremely poor during the production process of urea NX fiber.

Depending on the yield and fireproofing equipment, etc., the manufacturing cost of long fiber II#i strength high elasticity ash cord m fibers is becoming increasingly high.

As a method for producing long fibers of high 5g, 1 degree - elastic ash fiber in an inexpensive manner, a method for producing it using pitch containing mesophase as a raw material was published in Japanese Patent Publication No. 1,840-1984. It is well known that pitch containing mesophase is highly suitable as a precursor for long fiber high strength and high modulus carbon fibers. However, rather than producing long fiber high strength and high elasticity carbon edge M@ using pitch containing mesophase as a raw material, first there is a process of producing a pinch of RU secret body, a process of bathing the pitch, and a process of melt spinning fibers. It consists of four steps, including the step of infusibleizing the fiber, and the step of firing, carbonizing, and graphitizing the infusible yarn in an inert gas. The above four processes are completely different technologies, and it is necessary to develop unique technologies suitable for each, and each of the processes has an extremely large effect on the gL history and elastic modulus of the urea fiber. influence

Many methods have been published in Japanese Patent Publication No. 57-175, 664 for infusibility of pitch yarn tljc fibers.
, Japanese Patent Publication No. Sho ω-192, 723, etc. However, since the physical properties of these pitch-based fibers are opaque, they rotate through an infusibility furnace, so it is necessary to load ultrafine pitch yarns on a belt. However, the sudden contact of the pitch-based fibers in the stacked portions becomes an opaque component, so the infusibility of the pitch-based fibers becomes an opaque component.f! cH1, the degree of infusibility of the infusible filaments is not uniform; For this reason, it causes a great deal of trouble in subsequent processes, and it is difficult to produce long fibers with excellent physical properties.

[Problem that the invention seeks to solve]

The purpose of the present invention is to use petroleum-based pitch produced by thermal catalytic cracking (FCC) of desulfurized vacuum war oil as a raw material, so the strength of the pitch yarn NtKm produced by bath ## spinning is extremely small. It is extremely difficult to make it infusible. The Nth degree of this difficult problem is the subject of the present invention.

[Solving the problem = p stage]

The purpose of the upper δ pi is to convert the petroleum-based pitch of the present invention into 100% mesophase pitch t-jl for spinning with excellent physical properties, to create long-fiber pitch-based fibers by bath-melting this, and to utilize this ultra-fine physical property. The solution is to carry out a rational two-stage infusibilization method in an infusibilization furnace equipped with several tens of roller tubes.

The present invention involves vacuum distillation of petroleum pitch, which is produced as a by-product through thermal catalytic cracking (FCC) of desulfurized vacuum gas oil, and 85% distillation (initial distillation 460°C to final distillation 560°C) of non-oxidizing gas and stirring. A pitch containing mesophase (which can be recognized with a polarizing microscope) is produced by heat treatment at a temperature of 380°C to 420°C, and the resulting pitch is aged at a temperature of 300°C to 350°C for a period of time. 10 hours to 4
After 0 hours of ripening, only the Men7Aze in the pitch fuses and becomes gigantic, and in the warm axillary of ripening under non-oxidizing gas, non-mesopitch containing no mesophase in the upper layer (which can be easily seen with a polarizing microscope) ) and 100 in the lower layer.
It is clearly divided into related mesophase pitch (which can be easily confirmed with polarized light wA micro-sharp light) based on the difference in specific gravity.
Taking full advantage of the physical properties of separated and purified 100% mesophase pitch, it is melt-spun to produce a material with a strength of 5 to 12 kl/2, elongation of 1.1 to 1.8 kl. Pitch-based fibers were made, and the long fibers were coated with a sizing agent and wound onto a bobbin, and then rewound from the bobbin. The fibers are placed in an infusibility furnace equipped with 1 to 100 rollers, and run on the rollers. In the infusibility furnace, the fibers are first pretreated at temperatures of 150°C to 250°C below the softening point of pitch fibers.
The fibers are made infusible using 9 qi within the range of m degrees to determine the softening point of the fibers, and the fiber bundle, which has been pre-treated to have a high softening point as the main treatment in the second stage of Shun, is run on a roller. Using air containing 25% to 50% gold of oxygen, the infusibility temperature is 300°C.
Air with a high concentration of oxygen is circulated at a temperature of 360°C to 360°C, and the oxygen consumed by the infusibility of the air is constantly refilled from other sources, such as from an oxygen cylinder, and then used on a roller. By running the fiber bundle and applying tension to make it infusible, it is possible to smoothly achieve strength 10 industrially.
kg/degree 2 to 20 Yu/mX, elongation 1.8% to 3.0
% of the infusible yarn, and by utilizing this physical property, it becomes possible to wind the infusible yarn onto a bobbin.

By producing an infusible yarn having the above-mentioned physical properties, it is possible to smoothly carry out the firing process carbonization and graphitization process described below. It can be manufactured by adding fibers.

Example 1 Decompressing IM! Petroleum pitch, which is produced as a by-product by thermal catalytic cracking (FCC) of oil, is distilled under reduced pressure and cut by 85% (initial distillation 460℃ to final distillation 560℃). Pitch containing mesophase is produced by processing at a heating temperature of 400°C for 6 hours, and this produced pitch is aged at a ripening temperature of 320°C for a long time to fuse and enlarge only the mesophase in the produced pitch. Only the mesophase in the pitch is fused and becomes gigantic, and at the ripening temperature the upper layer contains no mesophase at all (non-mesopitch = *
The separated and refined 100% mesophase pitch is separated and purified using a spinning machine. The fibers were melt-spun to obtain long fiber pitch fibers with a strength of 8 kg/m'' and an elongation of 1.4%.

A sizing agent is added to the fiber bundle (2K = 2.000
(This filament) is twisted and wound onto a bobbin.

Since the Ivj yarn speed and the infusibility speed of the scooping yarn wound onto a bobbin are completely different, it is necessary to temporarily scoop out the yarn onto a bobbin and store it.

Extra-fine 2K (
2. Add a sizing agent to the Li2O (Li2O) using the sizing agent cold addition method (2), and temporarily scrape it onto the bobbin (3), then rewind it from the bobbin and run it on the roller (4). As a pre-treatment, the infusible was run over rollers (6) of 9'+ (zero force) at a running speed of 20 an/min at a temperature from sub-temperature to 220°C for (part) minutes with air. Perform preliminary disfluency.-220℃ to 340℃ as a modification of -t-
It is infusible in air with an oxygen content of 30% at a running speed of 20 an/min at a temperature up to %teC (7) long mia o fu7ka itoto (8
) is constantly under tension by the weight (9).

This infusible yarn bundle is temporarily stored on roller C1l.

The air used for this process is acidic, which is circulated, and the amount of oxygen used for the infusibility reaction is supplemented from outside, and the air used for this process is always 30% oxygen at a time. It is designed to be maintained.

First, the long fiber infusible yarn that is wound back from the bobbin αl is %l [
Calcined and carbonized in gas, temperature 2.60 in alnon gas
It is graphitized at 0°C to produce a high-strength, ultra-high elasticity fiber bundle of long fibers with a strength of 310 ksl/m'' and an elastic modulus of 68 T/2.

[Brief explanation of the drawing]

FIG. 1 is a perspective view for explaining a furnace used in the infusibility method of the present invention. FIG. 2 is a plan view of an illustration of the same furnace. FIG. 3 is a diagram showing the temperature distribution inside the furnace. l...Melting spinning machine 6...Roller in infusibility furnace 2...Sticting agent adding machine 7...Main body 3 of infusibility furnace...Roller of pitch yarn fi & 4i 8...
・Infusible yarn roller 4...Roller 9
... Weight 5 ... Spun fiber bundle (2K) 10 ... Infusible yarn bobbin No. SI! I

Claims (1)

[Scope of Claims] 1) Petroleum-based pitch is heat-treated to produce pitch containing mesophase, and this produced pitch is aged to fuse only the mesophase into a large size to produce 100% mesophase pitch (
(confirmed with a polarizing microscope) is separated and purified, and this 100%
Melt-spun mesophase pitch to create pitch-based fibers,
The fibers are fed into an infusibility furnace equipped with several tens to hundreds of horizontal rollers, and in the first stage of the furnace, the fibers are run on rollers at a constant speed for a certain period of time at a temperature below the softening point of pitch fibers. The pitch-based fibers are made infusible, the softening point of the pitch-based fibers is raised, and then the pitch-based fibers are heated in the furnace at a temperature higher than the infusibility temperature at the time of infusibility in the first stage. Two-stage infusibility is carried out by running at the same speed and for the same amount of time, and air is used in the first stage of infusibility in the furnace.
In the second stage of infusibility in the furnace, the amount of consumed oxygen is replenished by circulating gas containing 25% to 50% oxygen.
Furthermore, this method is characterized by two-stage infusibility by reusing heat. 2) In the above two-stage infusibility, both the first and second stages are run on several dozen to one hundred horizontal rollers at the same speed (5 cm/min to 5 cm/min) in the same infusibility furnace. 40cm/min)
In the first stage of infusibility, the pitch-based fibers are run from room temperature to 180°C to 250°C, which is below the softening point of the pitch-based fibers, for 20 to 60 minutes, and the second stage of infusibility is performed. By circulating air containing 25% to 50% oxygen and replenishing the consumed oxygen to maintain a constant high concentration of oxygen, the maximum temperature of the first treatment stage is 150°C. The same running speed (5cm
/min to 40cm/min) on a number of horizontal rollers in the furnace, the running time of the first and second stages is 20 to 6 minutes, respectively.
The method according to claim 1, characterized in that the method is carried out over a period of 0 minutes and by applying tension on a number of horizontal rollers.