JPS6264891A - Removal of non-flowable component of pitch - Google Patents

Abstract

PURPOSE:To produce pitch suitable for use as a raw material for a carbon fiber through separation of a non-flowable component of pitch with high efficiency, by pulverizing solid pitch, sifting the pulverized pitch using a sieve having a mesh size of a particular value, and removing the oversize. CONSTITUTION:Solid pitch is pulverized with a ball mill, a jet mill, an automatic mortar, or the like. The pulverized pitch is sifted using a sieve having a mesh size of 100 in terms of Tyler mesh, followed by removal of the oversize. The above method enables the separation of a non-flowable component of pitch with high efficiency and production of pitch suitable for use as a raw material for a carbon fiber with ease. This method also enables the production of a high-performance carbon fiber at low cost by virtue of the low cost of the raw material. A further improvement in separation of a non-flowable component can be attained by further melt filtering the pitch which has been passed through the sieve.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to the separation of carbonaceous or hydrocarbonaceous solids in pitch, and more specifically, the present invention relates to the separation of carbonaceous or hydrocarbonaceous solids in pitch, and more specifically, the present invention relates to the separation of carbonaceous or hydrocarbonaceous solids in pitch. C indicates a flow v1 and relates to a method of separating some components. [Prior art] In recent years, materials suitable for various uses have been developed, one of which is carbon. Among carbon-based materials (carbon, graphite materials), ]-x, graphite electrodes, etc. are known, but they lack heat resistance, conductivity, and light weight as materials. New products that take advantage of features such as corrosion resistance and corrosion resistance are also attracting attention.In particular, pitch-based carbon 1liH has the potential to be produced at low cost and with high performance, and many studies have already been published. The final characteristics of these products are expressed as a result of a combination of many factors, but one of the most essential elements is tit, the bamboo-like shape of the pitch used as the raw material. It is the intermediate structure and distribution of pitch that governs pitch.Since pitch is originally a mixture of balanced compounds, the molecular R distribution is wide, and the v1 of each component that makes up pitch is wide.
The quality has improved. Therefore, even if there is a slight difference in the grains during pitch manufacturing, the thorn shape of the pitch will be affected by this and the characteristics of the product will also change. For example, during heat treatment oh

The change in pip caused by Optical rate f1 pip progress J-ru.This J
, it is easy to obtain 100% optical Tatsumitake pitch by simple heat treatment of sea urchin pips. Even at the stage where the polymerization of the pitch has already progressed to a state where the fluidity f1 is poor, the parts close to the reaction still exhibit a state of superior hip, which means that the pitch is usually well-received. Such differences in the progress of heat treatment not only make it difficult to roll the product, but also make it difficult to roll during melting and during subsequent heat treatment.
When making a product like this, there may be problems with the molding process. A notable example of this is the hip type carbon ts111+. Manufacturing method of pitch-based carbon fiber (To, generally (a) Ishikawa pip or Riura pitch is subjected to treatments such as heat treatment to make pitch for spinning) - Culm, ([)) Two methods for spinning this Culm, (C) Process of infusible the spun yarn, (
d) Carbonized or graphitized fibers are broadly classified into culms. The above-mentioned spinning is performed by melt spinning. -[As mentioned above, since it is a mixture, there is an 8-speed difference in the polycondensation reaction even in the pitch, and if some of the polycondensation has progressed to a state where fluidity is poor even in the spinning preparation. , it moves as if it were an EJY object included in the pitch, causing blockage of the nozzle during spinning, making stable spinning impossible. On the other hand, if the heat treatment is terminated before the formation of 11 components, optically anisotropic mesophase components such as the unripe 1 minute t1 optically isotropic f1 pip component are mixed, so-called binary components. A state of phase separation occurs, and the viscoelastic behavior of the two phases during spinning causes yarn breakage to occur frequently. Also, the thread breaks > r
, it is possible to obtain stable quality carbon mH (1) with large variations in yarn diameter by setting the spinning thread A'1.Furthermore, the pitch is at the optically isotropic bamboo stage. If the heat treatment is finished at , a good pitch during spinning will be 1q,
It is not possible to obtain a high f/I binding string. For this reason, Pitch's J! ! Various proposals have been made regarding the law. For example, a method of heat treatment after hydrogenation (JP-A-5L-179285, JP-A-58-1)
8421), a method of further heat-treating the pitch that has been precipitated and separated after heat treatment (JP-A-57-88016), a method of using a solvent instead of the above-mentioned sedimentation (JP-A-57-88016.
-160427) and many others. The spinning pitch used in these methods all contains optical anisotropy, or is converted into an anisotropic set vA after firing, so that the pitch behaves as a homogeneous system during spinning. be. In other words, in order to obtain a uniform pitch without removing the polycondensation component of the overcharge, which causes blockage of the nozzle during spinning, treatment such as hydrogenation is performed in advance before heat treatment to reduce the pitch. The distribution is adjusted, the heat treatment is terminated when the overall ripening is insufficient, and the portion suitable for spinning is divided into H1. As described above, there are various methods, but under the processing conditions, an overcharged polycondensate component is generated.1! They have the same thing in common. This is because the components suitable for spinning and the components unsuitable for spinning that have polycondensed due to overcurrent are in a more uniform state when viewed from the pitch state, and the pip 1) is not in a roughly uniform state. Molecule 61 is formed with a wide distribution, and only the components that have polycondensed over time can be separated into 1iI.
This is because it is extremely difficult to do so. [Problems to be Solved by the Invention] By the way, in order to carry out the process strictly under the selected conditions and always obtain a uniform spinning pitch, an optimally designed device with a high degree of control 61I is required. The y1 equipment I had, original #1
It is necessary to refine the pitch from the stage, which increases the cost, and it is difficult to use low-priced pitch as raw material.
There was an inconvenience that 1) could not be achieved even if I had selected it, and that I could not demonstrate it in 1 minute. Honkomyo etc. (Carbon products made from BEIFl and 1 Pizji, etc.)
In particular, while researching high 4'L (1-carbon wire silk), conventionally we have used pitch that has been ground into pellets, or pitch that takes about 1 minute to make into pellets, into the spinning tube and spins it. However, it was discovered that by spinning using a finely pulverized pitch, the yarn becomes white during spinning.The present invention is based on the discovery described in Item 11 above. , it is an object of the present invention to provide a method for efficiently removing excessively polycondensed components, which have conventionally been rotated. The purpose is to achieve this purpose, and its gist is to remove the non-flowable components of pips by pulverizing the solidified pitch and sifting it with a mesh of 100 or more Tyler Messi = 1 (hereinafter referred to as Metshi 1). , and the solidified pitch is crushed, sieved with silk having a mesh number of 1 (') 0 or more, and the pitch that has passed through the screen is melt-filtered to remove the non-flowable components of the pip. - (Specific structure and operation of the invention) The excessively polycondensed lζ pitch component is separated by solidifying the lζ pitch component and sieving it with a mesh having a mesh size of 100 or more, particularly preferably 200 or more. Furthermore, by melting and filtering this separated pitch, it is possible to separate it with even better yield.This is thought to be due to the following reason.That is, the pitch can be separated by the polycondensation of As the pitch progresses, the molecular weight increases and as a result, the structure becomes stronger. Therefore, it is expected that the parts where polycondensation has progressed during grinding will be difficult to grind and will likely remain as large particles. There are various pulverization methods for pulverizing G-J, and no matter which pulverization method is used, it is impossible to avoid leaving G-J on the mesh, which is a part where polycondensation has progressed too much and is not suitable for the purpose. Although it seems impossible, in practice it has been found that a substantially 1-open operation is sufficient. A suitable part is considered to indicate that even solidified pitch has a considerable amount of By filtering, it is possible to completely remove the 11111. Grinding equipment #3L ball mill, digital mill, automatic mortar, etc. are suitable. Yo, Messi] Number 100
It is necessary to use a net with a mesh count of 1, preferably 2(')0 or more, and a net with a mesh count of less than 100 will greatly reduce its effectiveness.In addition, the net used for filtration (hereinafter referred to as the core material) must, of course, be A fine-mesh mesh is used for the sieve used for the sieve, but in general, the sieve size is 1t
A heartwood with an opening of about 1 to 2 mm is preferable, and is determined from the balance between the completeness of separation by filtration and the time required for filtration. This can be confirmed by microscopic observation. Another advantage of filtration is that it improves pitch yield. In other words, the combination of sieving and filtration 1
! When separating the components by sieving [
It is necessary to adjust the pulverization so that the size does not exceed the opening of the mesh used in the process. If the grinding is done in a controlled manner, the pitch, which should originally be particles of 100 mesh passes, remains in the net-V, resulting in a decrease in pitch yield. Furthermore, if the pitch is passed through a 6M melt without sieving, not only will the separation be poor and the yield will drop, but the amount of pitch remaining in the core material or on the filter medium will be large, resulting in clogging and impeding filtration. The time required increases and the filtration efficiency decreases. Furthermore, if the yield is poor, the overall composition and properties of the pitch before treatment may change. In this way, pitch is a type of mixture in which components with similar structures are continuously distributed, and techniques to control the physical properties of pitch depending on the purpose of use are important when using pitch. Separating a part of it and adjusting its physical properties was considered extremely rotational. The method of the present invention makes it easy to operate. The present invention will be explained below with reference to Examples and Comparative Examples. [Example 1] A 2 fJ autoclave was filled with lahydroquinoline as a solvent at a weight pressure of coal tar pip:solvent-1:1, and under a hydrogen pressure of 90 K'J/on, 47
The pitch was hydrogenated by holding at 0° C. for 1 hour. The obtained hydrogenated pitch was filtered and treated under reduced pressure under heating to obtain a heat-treated raw pitch. This ready-to-heat-treated raw material pitch was placed in a flask and treated at 470° C. in a nitrogen atmosphere to obtain pitch for spinning. This pitch is placed in an automatic mortar (product name: Labo Mill, tJT-
21 type J771-manufactured by Kagaku), 20
The mixture was sieved through a 0-mesh stainless steel screen. The sieved pitch is filled into a spinning tube equipped with a 0.38φ monohole nozzle at the bottom and a stainless steel mesh of 325 mesh 1 set as a filter material, and the inside of the spinning tube is made into an inert gas atmosphere. and cooled to 340°C. After raising the temperature, the pip was extruded from the nozzle by pressurizing it to 4 Kg/ctA with nitrogen gas, and was wound up at a speed of 800 m/min using a winder. The spinnability was extremely good, and the diameter of the pitch yarn was stable. Ta. In addition, the analytical values obtained by solvent fractionation showed no difference from the spinning pitch before these treatments. In addition, the pitch that remained on the 200 mesh screen after sieving and the pitch that passed through the screen were heated to the spinning temperature of 340°C for 10 minutes to melt them, and then cooled for 1 hour. It was solidified with rI and photographed using a polarizing microscope. This is shown in FIGS. 1 and 2. The remaining pitches in the net in Figure 1 include 60 to 300 pitches.
Unmelted portions of .mu.m in size were observed here and there, but they were not observed at all in the pitch that passed through the mesh shown in FIG. [Example 2] Spinning was carried out in the same manner as in Example 1, except that the mesh used for sieving was 100 meshes, and the mesh used for filtration in the spinning cylinder was 200 meshes. The yarn breakage and yarn diameter variations were almost the same as in Example 1, indicating good spinnability. [Example 3] Spinning was carried out in the same manner as in Example 1, except that the mesh used for sieving 1J was a 10(') mesh and no mesh was placed in the spinning tube. The yarn breakage and yarn diameter variations were almost the same as in Example 1, and good spinnability was exhibited. [Comparative Example 1] Example 1 and all ( As a result, the nozzle was clogged to a considerable extent, and irregular fluctuations in the pitch flow rate, so-called pitch pulsation, were observed due to the pitch being slightly separated into two phases. A phenomenon was observed under the nozzle, and the frequency of yarn breakage was high and the variation in yarn diameter was large compared to any of the examples.Also, when looking at the solvent separation, the spinning pitch before these treatments was It was observed that the distribution had changed considerably. [Comparative Example 2] The pitch remaining on the 30 mesh mesh in Comparative Example 1 was further ground and sieved again using the 30 mesh mesh. The pitch that passed through the sieve and the pitch that passed through the 30-mesh screen in Comparative Example 1 were thoroughly mixed and then spun under exactly the same conditions as Comparative Example 1. As a result, the results were as follows: The pulsating phenomenon that occurred during sieving disappeared, and the frequency of yarn breakage and the variation in yarn diameter were significantly improved. [Comparative Example 3] Spinning was carried out in the same manner as in Comparative Example 2, except that the spinning pitch obtained in Example 1 was taken out of the flask and filled into the spinning tube. Compared to Comparative Example 2, the spinnability was further deteriorated, the nozzle was frequently clogged, and spinning was impossible. [Comparative Example 4] Same as Comparative Example 3 except that a filtering net was not inserted into the spinning tube. As a result, spinning was impossible due to the same phenomenon as in Comparative Example 3. The results of Examples 1 to 3 and Comparative Examples 1 to 4 are summarized in Table 1. [Margin] 1st [Effect] The method d1 according to the present invention described above can efficiently divide the non-fluid component of the pitch, which was conventionally considered as office work.
ft-v, it is easy to obtain a suitable pitch for raw stones for carbon products, especially carbon cord, and combined with the low cost of raw materials, it is possible to produce high-performance rope fibers at low cost. It is possible to do so, and its impact is extremely great.

[Brief explanation of drawings]

Figure 1 shows the powdered pitch and sieved with a 200 mesh mesh.
The pitch remaining on the net was heated to 340℃ to melt it, then cooled and solidified.
This is a microscopic photograph of mesh-passed pitch heated and melted at 3/IO° C. and then cooled and solidified with HI. 1...Flow structure, 2...Insoluble part. Procedure City J Toki (Method) % Formula % 2. Name of invention Method for removing non-fluid f1 component of pitch 3. Person making correction f! l What relationship Special feature 1 Applicant (200) Showa Denko Co., Ltd. 1-4, Agent 7-1-5, Yaesu 2-chome, Chuo-ku, Tokyo Contents of amendment Inner box, page 17, lines 9 to 16 Delete the brief description of the drawing up to line 1.

Claims (4)

[Claims] (1) Grind the solidified pitch, and the number of Tyler meshes is 1.
A method for removing non-flowing components of pitch, which comprises sieving with a mesh of 0.00 or higher and removing the portion on the sieve. (2) A method for removing non-flowable components of pitch according to claim 1, which is applied to spinning pitch for producing high-performance carbon fibers. (3) Grind the solidified pitch, and the number of Tyler meshes is 1
A method for removing non-flowing components of pitch, which comprises sieving through a 00 or higher mesh, and then melting and filtering the pitch that has passed through the mesh. (4) A method for removing non-flowable components of pitch according to claim 3, which is applied to spinning pitch for producing high-performance carbon fibers.