DE2038949A1 - Process for the production of non-flammable fibers - Google Patents

Description

DK. ING. E. HOFFMANN · DIPL. ING. W. SITLE · DH. HER. NAT. K. HOFFMANN

PATBKTANWiMPK
D.8000 MDNCHEN 81ARABEUASTRASSE 4 TELEPHONE (0811) 911017 u 19308

Kanegafuchi Boseki Kabushiki Kaisha, Tokyo, Japan

METHOD OF MANUFACTURING NON-FLAMMABLE FIBERS

The invention relates to an improved method for making carbon fibers.

In more recent times, carbon fibers have been considered fibrous Materials with various excellent properties attracted attention. Such properties are e.g. their good fire resistance, heat resistance, corrosion resistance, their good electrical properties Conductivity as well as its insulating capacity.

In terms of fire resistance, carbon fibers have the corrosion resistance, the insulating property and the like properties similar or even better like fiberglass. They have essentially the same strength as glass fibers. In addition, some have

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Carbon fibers have electrical conductivity, which Naturally, they do not have glass fibers. After all, carbon fibers are in terms of their heat resistance in non-oxidizing atmospheres considerably better than glass fibers and have a low density. on the other hand However, carbon fibers have a particularly low elongation and they are already in use broken under very little tension. It has so far been impossible according to the conventional manufacturing methods been to provide carbon fibers with a sufficient length.

The manufacture of carbon fibers is in up to now the manner of spinning cheap types of pitch and charring the fibers obtained.

The starting fibers obtained from pitch have a significantly higher carbon content than fibers made from cellulose, Polyacrylonitrile and lignin, so that the yield in the charring stage is considerably higher and the losses are low. Therefore, the charring step can be easily performed in a short time. on the other hand but the handling during spinning or after spinning is compared to the starting fibers made of polyacrylonitrile and the like more difficult.

The invention is therefore based on the object of providing carbon fibers with excellent physical properties in a technically simple manner and with high yield to manufacture.

The invention is therefore a method for

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Manufacture of carbon fibers, which is characterized in that a separately melted pitch and a synthetic organic polymer are spun simultaneously through a common nozzle into a composite fiber in which both components are uniformly connected along the longitudinal direction of the unitary thread, the resulting composite a fiber is subjected to oxidation treatment, and at least two hours to a fixing treatment in air or in nitrogen gas at a temperature of 200 to 500 ⁰ C and in that then at least once performs a carbonization treatment at a temperature of more than 80O ⁰ C in nitrogen gas.

Under the term "carbon fibers" such which are composed of carbon. The fibers are also said to be non-flammable fibers include, in which the carbon does not have a crystal structure, but an organic amorphous structure, Carbon fibers, in which the carbon is in microcrystalline form, and finally graphite fibers, in which the carbon has a pronounced crystal structure and a fibrous structure having.

In the above described non-flammable fibers of the fiber-forming carbon has an amorphous structure, such that the fibers have a heat resistance temperature of about 250 - 300 ⁰ C and have show an electrical insulation. The carbon fibers that are composed of microcrystalline carbon

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are, have a higher heat resistance than the non-flammable fibers as well as an electrical conductivity. The graphite fibers are the ones in terms of heat resistance and electrical conductivity superior to the above non-flammable fibers and the carbon fibers.

. The pitches useful in the process of the invention include petroleum asphalt, coal tar pitch, petroleum slag and a pitch obtained from charring polyvinyl chloride. All types of bad luck can are melt spun. These pitches can provide carbon fibers by spinning them alone and the obtained thread an oxidation treatment and then subjected to a burning treatment. With regard to the Carbon content, petroleum asphalt and coal tar pitch are most preferable.

As thermoplastic synthetic polymers useful in the method of the invention, there can be any known ones synthetic organic polymers with thermoplastic properties are used, e.g. polyamides, Polyester, polyester-ether, polyolefins, polyvinyl chloride, polyvinylidene chloride, polyurethanes, polyacrylic plastics and copolymers, modified polymers, and mixtures thereof. Polyolefins are particularly preferred like polyethylene, polypropylene etc-

Thermosetting synthetic organic polymers include for example, epoxy resins, phenolic resins, etc. A. It is preferred without the addition of a thermosetting agent

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to work.

The conjugate spinning of these pitches and the thermoplastic ones or thermosetting polymers can be carried out by the conventional conjugate spinning process paying no particular attention to the spinneret and conjugate spinning of the two components must be judged. For example, the conjugate spinning of petroleum asphalt, which takes place in the melt and of polyamides are carried out at temperatures of 200 to 300 ° C using a spinneret, which holes with a diameter of 0.1-0, M- mm Has.

The connected structure of the two components described above can be either a side-by-side arrangement or a sheath-core arrangement. She can be due to Considerations about the ease of handling and handling of the spun fibers should be selected.

To achieve a high carbon yield Starting fibers to carbon fibers are starting fibers with a high carbon content in terms of the Preferable to yield and other considerations. Accordingly, starting fibers are high in the ratio of Preferable to Peoh. In view of the ease with which various procedures such as des '■■ rinm-TiSj Φ?, Ε recording, unwinding .and the like, - or • In terms of spinning speed, it is preferred that the

ν. ι jMgifcrungsverhältnis Pech mi thermoplasti the "oh .." - .. η e'er warat-ih &-curable synthetic ·:] s organic oly- ■■■ ■ - ¹ ^ n 1:? 1 - 1Oi 1, better 2 ; 1 - 6: 1, preferably 3; 1 - 5: 1,

When the conjugation ratio of pitch to the synthetic organic polymers is less than 1: 1, then the spinnability and the subsequent handleability is true good, but the ratio of the carbon content is lower so that charring is not easy can be carried out. In addition, the yield of carbon fibers is reduced.

Conversely, if the conjugation ratio is greater than 1 (5; .§ is, then the hardening and charring of the obtained fibers made lighter, and also the The yield of carbon fibers increases, but yarn breakage often occurs during spinning, so that the conjugate Spinning can be difficult to do. To reduce such a yarn breakage, must Take-up speed can be reduced to around 500 - 700 m / min, which is the usual take-up speed is when spinning a continuous thread that is composed only of pitch. However, it is difficult to obtain uniform composite fibers at such a low take-up speed ..

If 1: k ^{j :} -m \ ■■ ■ '■: ■ <■>, mv-i äev Penhe to: · the usual synthe ti; on · ->' ■ -y ·. ■ > - ■■■■■ !: ο η! - 'iLyaisren elm * Tensile stress exerted w .i'"el^{.; Ί} ". :::: .. ■■ ■; \ ■;: · '. · '? ■' - s: c = i die - '· ίϊ \ a stung even

un r'.ar .. ■■ .. · ■ ■■■ .. " "^; ΐ · .-. · "'.Iß · ^.: ■>. ·"' ■ ι ^ & ν · \ br v:; hen. If J ^e ""

dc ■■; ■■■ ■ ^; ,. ■■. = .3ß ei · .-. ■ ^; - '' ■■ ι ■ ι. _J Λd ■ ■ ·, y: ι ■ -; ιeti she οrfi, a.ηi- «ο;: ··· ^;: . - ,; ·. ·? and there - .. · ^Cl -: 'ih. ■ '.' ■. • ni'.i. '. I '> e "versp -'- iOvi; ' be

BATH ORIGINAL

then the synthetic organic polymer withstands the load and the melt spinning can be carried out steadily the take-up speed can be increased to 1000 to 2000 m / min. Furthermore can the spinning tension can be increased, so that carbon fiber η can be made with a finer number of yarns.

As stated earlier, the is conjugated Spinning the pitch and the synthetic organic polymers is very important in every bond structure of the two components. This is the case, for example, with regard to the It is preferable to penetrate the oxidizing agent in the oxidizing treatment, the polymer described above and conjugate spinning the pitch in a side-by-side arrangement or in a sheath-core arrangement. at In the latter, the synthetic organic polymer is arranged as the core component and the pitch as the shell component.

However, if both components are conjugated spun in a side-by-side arrangement, then it is expedient to select such a binding structure that the two components are not separated during the treatment will. According to the invention it is preferable to arrange both components in a sheath-core arrangement, in which the pitch forms the core and the synthetic organic polymer forms the shell. In this case it is because the core of pitch from the synthetic organic Polymer is surrounded, possible, such a composite thread in the same way as to handle a conventional composite thread.

-.Λ .. ■ *: ■■; · ■ · ■. ■ ·. ' ^r - • - - ■ - 8 -

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Taking into account the permeation of the oxidizing agent in the oxidizing treatment, it is preferable to that the shell is thin. It is appropriate that the thickness of the shell of the synthetic organic polymer in the The cross-section of the composite thread is less than 1/5 of the diameter. When the bad luck and the synthetic Organic polymers are conjugated spun in a sheath-core arrangement, then the number of "Cores are more than 2.

That by conjugate spinning the pitch and synthetic organic polymer according to the invention Spun fibers obtained are much more flexible than the fibers produced by melt spinning pitch alone can be obtained. In terms of their resistance to the stress of stretching, they are significant improved. Finally, the spun fibers can be picked up very easily.

According to the invention, the spun fibers are first subjected to an oxidation treatment. For oxidation inorganic or organic substances such as oxygen, air, ozone, hydroperoxide, hypochlorites, Bichromates, permanganates, benzoyl peroxide, cumene peroxide and the like can be used.

The oxidation treatment renders the pitch and synthetic organic polymer infusible and into organic Solvent insoluble.

The oxidation treatment is carried out in the gaseous phase or in the aqueous phase using the above-described

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NEN oxidizing agent carried out. Oxidation in the gas phase is carried out using oxygen, air, Ozone and hydroperoxide * The oxidation in the aqueous phase is carried out using hydroperoxide, hypochlorites, Bichromates, permanganates, benzoyl peroxide,

♦
Cumene peroxide and the like. Performed.

When the pitch forms the surface of the fiber, it is preferable to carry out the oxidation in the gaseous phase using ozone and the like. In the case of oxidation by ozone, the oxidation is carried out for 10 minutes to 5 hours at temperatures of 20 to 200 ⁰ C.

If the oxidation treatment is carried out in the aqueous phase, there is a risk that the fibers will become sticky will. It is preferred to use an aqueous hydroperoxide solution that contains at least one salt of manganese, Contains iron, cobalt and nickel of organic or inorganic acids to prevent stickiness. An aqueous solution of the sodium, potassium, calcium and barium salts of permanganic acid can also be used for this purpose use.

When using an aqueous solution of hydroperoxide, the above-mentioned salts of manganese, iron, Cobalts and nickel with organic or inorganic acids added to prevent stickiness.

These salts can be mixed with inorganic acids such as hydrochloric acid, Sulfuric acid and phosphoric acid or with organic acids such as acetic acid and oxalic acid

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The concentration of the hydroperoxide in the aqueous solution is suitably in the range of 1 to 30 Weight percent selected. The content of the above metal salts in the aqueous solution is 0.05 mg up to 5 g as anhydrous salts per 1 l of the aqueous solution of the hydroperoxide, preferably 0.2 mg to 1 g.

When the concentration of metal salts in the aqueous Solution of the hydroperoxide is below the lower limit, then the rate of decomposition of the hydroperoxide is too small and it is therefore difficult to sufficiently oxidize the spun fibers and make the fibers unmeltable and to make it insoluble. On the other hand, if the concentration is above the upper limit, then the decomposition rate of the hydroperoxide is too high and the hydroperoxide decomposes in too short a time Time so that it is difficult to continuously generate the nascent oxygen.

The spun fibers are treated 1 minute to 2 hours at 0 to 90 ⁰ C, preferably 10 to 80 ⁰ C in the above-described aqueous solution of the hydroperoxide. The pH of the aqueous hydroperoxide solution can be 1 to 13.

In the case that the oxidation treatment of the spun fibers is carried out in the aqueous hydroperoxide solution is and the treatment process is not limited, the spun fibers, if they are with the aqueous hydroperoxide solution, which contains the metal salt

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contains, are brought into contact, oxidized and converted to infusible and insoluble fibers.

For example, the spun fibers can be passed through the aqueous hydroperoxide solution. The spun Fibers can also be formed into a strand and then immersed in the aqueous solution. The spun Fibers can also be wound around a perforated spool and then immersed in the aqueous solution will.

To make the spun fibers effective with the treatment solution To bring into contact, one can in the treatment solution 0.01 to 3, weight percent of a surface-active Dissolve means. The surfactant can be anionic, cationic, nonionic or amphoteric Be nature. For example, an anionic-nonionic surfactant can be used.

In this case, the hydroperoxide is used in the oxidation treatment of the spun fibers rapidly decomposed by the catalytic effect of the metal salts and by heating and releases nascent oxygen. The nascent oxygen acts on the spun fibers and oxidizes them, so that they are converted into high fusible and insoluble fibers.

When the spun fibers are in an aqueous phase through an aqueous hydroperoxide solution containing a metal salt contains, are oxidized, then this oxidation treatment can be repeated several times in the aqueous phase if necessary. Furthermore, after the

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Oxidation treatment / the aqueous phase a wide / Tn re oxidation treatment can be carried out in the gaseous phase. The oxidation treatment in the gaseous The phase takes place in air or in an oxidizing atmosphere at a temperature below 26O ° C Shutdown of hydroperoxide or another oxidizing agent on the fibers in a dissolved state or on some other suitable manner without it being deposited.

If the oxidation treatment is carried out using an aqueous permanganate solution, then is the potassium salt is particularly preferable. In this case the treatment can make the spun fibers infusible and to make it insoluble, be done in an aqueous solution of a permanganate or one can after one on the spun fibers have an aqueous solution of a permanganate applied, the oxidation in the gaseous Perform phase in air.

The concentration of the permanganate in the aqueous solution is preferably at least 0.6 percent by weight. As far as the concentration of the salt is more than 0.6 percent by weight, a saturated solution can be used will. If the concentration is less than 0.6 percent by weight, then the spun fibers can cannot be sufficiently oxidized and it is impossible to make the spun fibers infusible and insoluble. Furthermore, the concentration of the permanganate in the aqueous solution in relation to the treatment conditions, in particular the treatment temperature, be selected appropriately. The pH of the

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aqueous solution of the above salt is not particularly limited. The oxidation treatment with such a solution can be carried out in the same way as in connection with the aqueous solution of the hydroperoxide has been described.

When the spun fibers by oxidation in a gaseous Phase after oxidation has been made infusible and insoluble in an aqueous phase, then it is preferable that the above-described solution of the salt be uniformly applied to the spun fibers beforehand has been deposited.

In order to deposit the above-described aqueous solution of the salt on the fibers, the fibers are placed in the aqueous solution Solution of the salt dipped or sprayed with the aqueous solution of the salt.

The amount of aqueous permanganate solution on the Surface of the fibers is deposited in the gaseous phase before oxidation is at least 0.1 Ge * part by weight of the pure salt component per 100 parts by weight of the fibers. When the amount of deposited pure If the salt component is below the lower limit, then it is impossible for the spun fibers to suffice infusible and insoluble, so that such an amount is not appropriate. As in the case of the watery Hydroperoxide solution, a wetting agent can be added to the aqueous solution described above. The oxidation treatment can be carried out either in the aqueous phase or in the gaseous phase. It can also prepare a variety of oxidation treatments

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be taken.

The temperature of the above oxidation treatment in the aqueous phase is from O to 90 C, preferably 10 to 80 C. In the case of the oxidation in a gas phase, it is preferred that the temperature of hot air is below 260 ⁰ C. Further, in each case of the aqueous phase and the gaseous phase, the treatment time is 1 minute to 3 hours. It is selected taking into account the salt concentration in the aqueous solution, the treatment temperature and other operating conditions.

After the oxidation treatment in the gaseous and in the aqueous phase, the spun fibers are treated and fixed in air or in nitrogen gas for at least 2 hours at 200 to 500.degree. After this treatment, the fibers are non-flammable fibers. The heat resistance and the flame resistance temperatures of these fibers are at most 250 to 300 ^° C. The fibers are electrical insulators. Accordingly, when the heat-resistant temperature is within the above-described range or when the fibers are used as an electrical insulator, the non-flammable fibers can be used as such. The fixing treatment is generally carried out in air at 200 to 350 ° C. for 2 to 1 hours.

Those obtained by the above-described treatment non-flammable fibers are at least once, carbonized in a nitrogen atmosphere and at a high temperature which is above 800 ⁰ C. In the fixation treatment

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In addition, heat treatment in the presence of air is rather preferable in order to accelerate the reaction, while the charring treatment, since it is carried out at a high temperature, must be carried out in an inert gas such as nitrogen. If the temperature for the carbonization is 800 to 1.80Q ⁰ C, then carbon fibers can be obtained with a microcrystalline carbon structure. If the temperature for the charring treatment is increased to 2,000 to 3,500 ^° C., carbon fibers with a graphite structure, namely graphite fibers, can be obtained. The charring treatment can be a two-stage treatment in which the non-flammable fibers are ^{heat-treated at a temperature of 800 'to 1,800 °} C. and then further treated at a temperature of 2,000 to 3,500 ° C., or it can be a single-stage treatment in which the non-flammable fibers Fibers at a temperature of 800 to 1,800 ⁰ C or a temperature of 2,000 to 3,500 ⁰ C are treated.

The charring time depends on the type of pitch and the synthetic organic polymers, conjugate spinning conditions and charring temperature, and Like. From and is generally 10 minutes to 10 hours.

According to the invention, the fixing treatment or the charring treatment of the oxidized fibers can be carried out in one appropriate stage can be selected depending on the properties of the desired carbon fibers.

According to the invention, the spun fibers can easily,

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oxidized uniformly and rapidly and converted to infusible and insoluble fibers, the oxidized Fibers are non-sticky, are flexible and maintain the shape of the fibers spun can be handled very easily. Accordingly, the fibers become like not deformed in the conventional case, the shape of the spun fibers is maintained and one can ρ easily come to carbon fibers with sufficient flexibility. The spun fibers thus obtained are the spun fibers in terms of their flexibility and their resistance to stretching superior to those obtained by the conventional carbon fiber production method. Further no yarn breaks occur during spinning and the pick-up can be carried out in a simple manner. The fibers can thus be produced in a technically simple manner. One can thus use carbon fibers improved properties and come with sufficient lengths.

The invention is illustrated in the examples. In the absence of any information to the contrary, the percentages are given in these based on weight.

example 1

Nylon-6 chips having an intrinsic viscosity of 1.2, measured in m-cresol at 30 ⁰ C were used as core components. Petroleum asphalt with 8 5.8% carbon was used as the shell component. This asphalt was obtained by using blown asphalt (manufactured by Maruzen Sekiyu KK) having a softening point of

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15O ⁰ C was subjected to dry distillation in nitrogen. The two spinning materials were conjugated with a conjugation ratio (weight) of core / shell of 1: 4 at a temperature of the melting device of 280 ° C. through nozzles with a diameter of 0.2 mm. The spinning took place in air at room temperature. Thereby, composite fibers having a sheath-core arrangement were obtained. The spun fibers were at a distance of 6 m * just below the nozzles arranged coil with a recording speed of 500 m / min, was added from a.

When the obtained composite fibers were unwound from the bobbin, neither breakage nor deformation occurred. In addition, the bond between the asphalt and the nylon-6 was very good.

The spun fibers were immersed in the form of a strand in a 36.5% aqueous hydroperoxide solution at 25 ° C. for 24 hours in order to oxidize the surface. The fibers obtained were suspended in a tube, etc.

at a rate of 5 ° C / min. in the presence of air, heated to 280 ° C, and held at this temperature for two storms. The fibers were heat set. After this heat-setting, the fibers were heated at the same rate in nitrogen at 1,000 ⁰ C, held for 30 minutes at this temperature to carry out the carbonization and so then cooled to room temperature. Carbon fibers were thereby obtained. The carbon fibers obtained had a strength of 8 t / cm and an elongation of 1.8%.

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Comparative example

The petroleum asphalt TUs Example 1 was heated and melted in a melting alone device to 280 ⁰ C and through nozzles having a diameter of 0.2 mm in air at room temperature spun. The spun fibers were taken up on a bobbin, which was arranged at a distance of 1 m from the nozzles, at a take-up speed of 200 m / min.

When taking up the spun fibers under the same conditions as in Example 1, that is, at the spacing of 6 m and the take-up speed of 500 m / min., The fibers broke and it was not possible to take them up. The workability was considerably inferior to that of the fibers of Example 1.

In addition, the fibers picked up under the conditions given above had very low strength. In addition, they were deformed during unwinding, oxidation and heat setting. For these reasons, it was impossible to make long filamentary carbon fibers.

Example 2

Epikote 1009 (trademark for an epoxy resin from Shell International Chemicals Corp ..) was used as the core component used. Coal-tar pitch was used as the shell component used with 86.2% carbon. The spin materials were melted and in a conjugation ratio (Weight) of core / shell of 1: 6 conjugated spun at a temperature of 220 ° C. It was made with the same

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Chen nozzles worked with a diameter of 0.2 mm. The spun fibers were taken up at a take-up speed of 100 m / min.

The composite fibers obtained did not break during any of the various stages of the process or deformations.

The composite fibers were subjected to an oxidation treatment in air which contained 8 11 g / m ^{3 of} ozone for 1.5 hours at 70 ^° C. in order to render the fibers infusible and insoluble. Then, the fibers were heat-set in the presence of air and subjected to charring treatment in nitrogen in the same manner as in Example 1, whereby carbon fibers were obtained. These have
Elongation of 1.5%.

became. These have a strength of 9 t / cm and a

Example 3

A side-by-side composite fiber spinneret was used in which one component entered the other component in the form of a neck so that the two components did not separate. Petroleum asphalt according to Example 1 was used as one component. As the other component, Yukaron YM-60 (trademark for a high pressure polyethylene by Mitsubishi Yuka KK) was used. This spinning materials were melted and with a Konjugierungsverhältnis of petroleum asphalt / polyethylene of 2: 1 conjugate spun at 260 ⁰ C. The spun fibers were taken up under the conditions described in Example 1.

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The obtained composite fibers could undergo various treatments under the same conditions as in FIG Example 1 are subjected to the thread structure was maintained without breaks and deformations. It could be carbon fibers with a strength of

2
11 t / cm and an elongation of 2.0% can be obtained.

example

Petroleum asphalt according to Example 1 was used as the core component and Noblen MA-3A (trademark for a polypropylene resin from Mitsubishi Yuka KK) was used as the shell component. This spinning materials were melted and conjugated mm in various KonjugierungsVerhältnissen at a temperature of the fusing device of 290 ⁰ C through nozzles having a diameter of 0.2 spun. They were spun in room temperature air as described in Example 1 to produce composite fibers having a sheath-core arrangement. The spun fibers were brought into contact with a 5% benzoyl peroxide solution in benzene between the nozzles and a spool, whereby the benzoyl peroxide was applied to the fiber surface. The fibers were then wound onto the spool. The fibers obtained were oxidized for U hours in air with the ozone concentration of Example 2 at 80 ^° C. in order to make the fibers insoluble and infusible. Then, the fibers were heat-fixed in the presence of air and subjected to nitrogen in the same manner as in Example 1, a carbonization treatment at 1,000 ⁰ C. In this way, carbon fibers were obtained. The results obtained are shown in Table 1 below.

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Table 1

Sample no.

jConjugation ratio
Jnis von Kern /
•Covering

{Properties of the strengthening, · "" V ". ^, · +. «Fibers according to the Spinnability {charring treatment! - carbon

Ilung at 1,000 C | fabric fibers • j (t / cjiT)

excellent {brittle and easy} «to break {

"{Stickiness between 'part of the

isern

ti

U ti

{borrows rigidly
•very flexible

Well

The fibers bre-charring is very often and possible the spinning {
is impossible ι

10 11 11

Example 5

A pitch from thermally cracked polyvinyl chloride having a softening point of 170 ⁰ C was used as a core component and a novolac resin having an average molecular weight of 1,200 was used as the sheath component. The pitch was melted at a temperature of the melting device of 220 ^° C. and the novolac resin ^{at a temperature of 170 °} C. The two components were conjugated spun at a core / shell conjugation ratio of 5: 1 through nozzles with a diameter of 0.3 mm. A nozzle temperature of 220 ° C. was used. The obtained composite fibers having a sheath-core arrangement were attached in air

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Spun at room temperature. The spun fibers were on a bobbin with a take-up speed of 1,000 m / min, recorded.

The raw fibers obtained were immersed in a 20% strength aqueous hexamethylenetetramine solution for 2 hours. Then the fibers were oxidized in an ozone-containing air according to Example 1 for 2 hours at 80 C to make them infusible and to make it insoluble. The fibers were further processed in the same manner as in Example 1 in the presence of air heat-set, whereby non-flammable fibers 8 are obtained became.

Then the non-flammable fibers 8 were divided into two parts. One part was moved at a rate of 3 ° C / min. heated in dried nitrogen at 1,000 ⁰ C, held for one hour at this temperature and cooled in Stikstoff to room temperature, whereby carbon fibers were obtained. 9 The other part was heated at a rate of 3 C / min. heated to 2,500 ° C. in dried nitrogen, held at this temperature for 30 minutes and cooled to room temperature in nitrogen, whereby graphite fibers 10 were obtained.

The properties of the fibers obtained are summarized in Table 2 below.

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Table 2

j fiber
ι specific
great weight strength
(t / cm *) Elasticity J
(10 ³ t / cm ^z ) ι I.
Non-flammable
ibaric fibers 8
!Carbon-
j fibers 9
ιgraphite
I fibers 10 1 »2
1.5
1.8
ι 4.3
10
16.5 k
0.2;
I.
0.7 y
3.1 y

Example 6

Petroleum asphalt with a softening point of 2M-O ⁰ C was used as the core component. This was obtained by subjecting blown petroleum asphalt to dry distillation at 280 ° C. for 4 hours in the absence of air at a reduced pressure of 2 mmHg. As height component of polyethylene terephthalate having a relative viscosity of 0.62 measured in o-chlorophenol of 30 ⁰ C. These spinning materials were conjugated with a core / shell conjugation ratio of 4: 1 at a melting device temperature of 300 ^° C. through nozzles with a diameter of 0.25 mm. Spinning was carried out in air at room temperature in the same manner as in Example 1. The spun fibers were brought into contact with a 2% aqueous solution of cobalt chloride between the nozzles and a bobbin, whereby the cobalt chloride was applied to the fiber surface. The fibers were then taken up on the spool. The fibers thus obtained were immersed in a 36% aqueous hydroperoxide solution at 25 C for 24 hours in the form of a strand,

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to oxidize the surface. Then, the fibers in the presence of air under the same conditions as have been heat-set in Example 1, and further carbonized in nitrogen at 1000 ⁰ C and fired, whereby the desired carbon fibers were obtained. These had a fe-

2
capacity of 10 t / cm.

Example 7

"The composite fibers obtained in Example 1 with a sheath-core arrangement were immersed in and in an aqueous solution in the form of a strand for 10 hours oxidized. This contained 10 percent by weight potassium permanganate and a small amount of sodium alkylbenzenesulfonate as a wetting agent and it was kept at a temperature of 60.degree. C. and a pH of about 7.

The fibers thus treated were placed directly in an electric oven without washing and drying placed under nitrogen at a rate of 5 C / min. heated to 1,000 ° C at this temperature b held for 30 minutes to perform charring treatment, and cooled to room temperature, whereby carbon fibers were obtained. The obtained carbon fibers had electrical conductivity and

2
a strength of 8.2 t / cm and an elongation of 1.5%.

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009887/2087

Claims (1)

Claims 1) A process for the production of non-flammable fibers, characterized in that a separately melted pitch and a synthetic organic polymer are spun simultaneously through a common nozzle to form a composite fiber, in which both components are uniformly connected along the longitudinal direction of the single thread, and that the composite fiber obtained is subjected to an oxidation treatment and to a fixing treatment in air or in nitrogen gas at a temperature of 200 to 500 ^° C. for at least two hours. 2) Process for the production of carbon fibers, characterized in that a separately melted pitch and a synthetic organic polymer are spun simultaneously through a common nozzle to form a composite fiber, in which both components are uniformly connected along the longitudinal direction of the single thread, which The resulting composite fibers are subjected to an oxidation treatment and at least two hours to a fixing treatment in air or in nitrogen gas at a temperature of 200 to 50O ⁰ C and that a charring treatment is then carried out at least once in nitrogen gas at a temperature of more than 800 ⁰ C. 3) The method according to claim Lödtfr 2, characterized in that * the composite fiber has a conjugation ratio (weight) of pitch to synthetic «organic poly - wmvmn of 1: 1 to 10: 1. 009887/2087 - 26 - 2Ü389A9 k ) The method according to claim 1 ate »2, characterized in that the composite fiber has a conjugation ratio of pitch to the synthetic organic polymers of 2: 1 to 6: 1. 5) Method according to claim 1 or 2, characterized in that the composite fiber has a conjugation ratio of pitch to synthetic organic polymer of 3: 1 to 5: 1. 6) Method according to claim 1 or 2, characterized in that the pitch and the synthetic organic poly mers are connected to one another in the composite fiber in a side-by-side arrangement. 7) Method according to claim 1 or 2, characterized in that the pitch and the synthetic organic polymer are connected to one another in the composite fiber in a sheath-core arrangement. 8) Method according to claim 7, characterized in that »that the pitch in the composite fiber forms the core. 9) Method according to claim 1 or 2, characterized in that the synthetic organic polymer is a thermoplastic polymer from the group consisting of polyethylene, poly propylene, polyamide and polyester . 10) The method according to claim 1 or 2, characterized in that the synthetic organic polymer "in warm flour" * Palyaeres from the Orupp "Epoxlt & ps" and phenol - 27 - BATH ORIGINAL 009887/2087 resins is. 11) Method according to claim 1 or 2, characterized in that the pitch from the group of petroleum asphalt, coal tar and pitch obtained by coking polyvinyl chloride is selected. 12) Method according to claim 1 or 2, characterized in that the oxidation treatment in a gas from the Group oxygen, air, ozone and hydroperoxide is carried out. 13) Method according to claim 1 or 2, characterized in that the oxidation treatment using at least a permanganate from the group of sodium permanganate, potassium permanganate, calcium permanganate and barium permanganate is carried out. A method according to claim 1 or 2, characterized in that the Oxidatxons treatment using a aqueous Hydroperöxidlösung is carried out, the at least one of the salts of the metals from the group manganese, iron, cobalt and nickel with an inorganic one or contains organic acid. 15) Method according to claim 11, characterized in that that the inorganic acid is hydrochloric acid, sulfuric acid and / or phosphoric acid. 16) Method according to claim 14, characterized in that that the organic acid is acetic acid and / or oxalic acid. - 28 - 009887/2087 17> Method according to claim 1 or 2, characterized in that that the heat-setting treatment is carried out at a temperature of 200 to 350 ° C for 2 to 4 hours. 18) Method according to claim 2, characterized in that the charring treatment is carried out at a temperature of 800 to 1,800 ^° C. 19) The method according to claim 2, characterized in that the carbonization is carried out in two stages, the temperature of the first stage 800 to 1800 ⁰ C and the temperature of the second stage is up to 2,000 3.5OO ° C. 20) Method according to claim 2, characterized in that the charring treatment is carried out in one stage at a temperature of 2,000 to 3,50O ^{0 C.} 009887/2087