DE1213334B - Foerm body made of carbonaceous material and a carbonaceous binder and process for their manufacture - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

C04b

German class: 80 b -8/12

Number: 1213 334

File number: U9950VIb / 80b

Filing date: July 9, 1963

Opening day: March 24, 1966

It is known to carbonize fibers, fabrics or other textile structures made of cellulose and, if necessary, to use them converted into graphite by further heating. In this way one receives formations from a certain Elasticity and flexibility.

It is also known to have porous molded bodies made of carbon or graphite with one in the heat to impregnate curable resin and then cure the resin by heating.

Finally, it has been proposed to use sheets of cellulosic fabric converted into graphite by heating to coat or soak with a carbonaceous binder those treated in this way Stacking sheets, heating the stacked structure to harden the binding agent and the whole thing then finally to heat up to about 900 ° C in order to char the binder. Laminates made in this way and moldings have proven valuable and useful in many respects. In some In some cases, however, there are disadvantages due to the anisotropy of the laminates or moldings. So is z. B. the flexural strength in the direction towards the fiber layer is not always sufficient, and the thermal The coefficient of expansion is not the same in all directions, especially at elevated temperatures.

These disadvantages are avoided in the invention.

The invention relates to molded bodies made of carbon-containing material and a carbon-containing material Binder. The shaped bodies are characterized in that they are used as a carbonaceous material fiberized, disordered charred tissue, preferably converted into graphite by heating Contain cellulose.

In a preferred embodiment, the moldings according to the invention also contain the binder in charred form, expediently converted into graphite by heating.

The invention also relates to a method for producing the shaped bodies described. This The method is characterized in that a charred tissue made of cellulose is fiberized, the fiberized Mixing pieces randomly with a charring binder, forming the mixture under pressure and finally heated until the binder is charred. If necessary, the mixture can be added heat to such a temperature that the binder is converted into graphite.

For example, phenolic resins, pitch, epoxy resins, furfural, furfural alcohol or mixtures of these substances come into consideration as carbonizable binders. A mixture of, for example, shaped bodies made of carbonaceous material has proven useful as a binder
and a carbonaceous binder and
Process for their manufacture

Applicant:

Union Carbide Corporation, New York, NY
(V. St. A.)

Representative:

Dipl.-Ing. H. Görtz, patent attorney,
Frankfurt / M., Schneckenhofstr. 27

Named as inventor:

William Clay Beasley, Lawrenceburg, Term.

(V. St. A.)

Claimed priority:

V. St. v. America from June 9, 1962 (208 510)

Weight percent phenolic resin, about 25 weight percent furfural alcohol and about 25 weight percent Furfural.

Good moldings are obtained if 1 part of the binder is used for 2 bis Parts of the charred tissue used.

In the production of the moldings, the molding and heating can optionally be carried out at the same time be performed. The moldings according to the invention are distinguished by high and low strength Density.

example 1

2 parts of a fiberized carbon fabric were mixed with 1 part of a mixture of 50 percent by weight phenolic resin, 25 percent by weight furfural alcohol and percent by weight furfural. The mixture. became a disk 25 cm in diameter and 7.5 cm in thickness under a pressure of 0.50 kg / mm ²

609 539/395

deformed and cured for 6 hours at about 130 ° C. The disk produced in this way was embedded in coke in a container, the air being prevented from entering by means of a 7.5 cm thick layer of charcoal and a 5 cm thick layer of sand. Then, the temperature was 10 ° C per hour to 600 ° C, per hour increased by 60 ° C to 800 ° C and kept at 800 ⁰ C for 2 hours. ^:

Some properties of the molded body produced in this way at room temperature are:

Bulk weight 0.94 g / cm ³

Flexural strength. ...

in the grain direction 0.984 kg / τητη ^{2 1S}

against the grain direction .. 0.633 kg / mm ²

Young module

in. fiber direction 0.70 kg / mm ² · 10 ³

against the grain direction .. 0.35 kg / mm ² · 10 ³

Electrical resistance

0.022 microohm / cm in the fiber direction

against the fiber direction .. 0.031 microohms / cm

Example2

A graphite fabric was used as the starting material. This was done until the disk was charred, as described in Example 1. Then the temperature increased by 15 ° C every hour to 500 ° C, increased by 60 ° C hourly to 800 ° C and held at 800 ° C for 2 hours.

The shaped body was then allowed to cool to 300 ° C. in the container.

Some properties of the molded body produced in this way at room temperature are:

40

Bulk weight 1.10 g / cm ³

The furnace was flushed every hour with 0.15 to 0.30 m ^{3 of} nitrogen to remove the volatile substances that developed. After cooling to about 500 ° C, the items were removed from the oven. , -

Some properties of the moldings produced in this way at room temperature are:

Bulk weight, 1.00 g / cm ³

IO flexural strength

in grain direction ^. 1.195 kg / mm ²

against the grain direction .. 0.352 kg / mm ²

_t _ 'Young module

in the direction of the grain i 0.5484 kg / mm ² · 10 ³

against the grain direction .. 0.1687 kg / mm ² · 10 ³

Electrical resistance

0.003 microohm / cm in the fiber direction

against the grain direction .. 0.007 microohms / cm

Flexural strength

in grain direction 0.773 kg / mm ² '

against the direction of the grain .. 0.211 kg / mm ²

45

Young module

in the direction of the grain 0.795 kg / mm ² · 10 ³

against the grain direction .. 0.225 kg / mm ² · ΙΟ ³

Electrical resistance

in the fiber direction 0 ^ 010 microohms / cm

against the fiber direction .. 0.024 microohm / cm

Example 3-

Discs produced according to Example 2 were comminuted and the pieces packed in a 50 cm long graphite container with an inner diameter of 23 cm.

The lid and the bottom of the container had small openings for the escape of volatile substances. which develop during the graphing. The container was placed in the hot zone of a tube furnace with a diameter of 25 cm and heated to 2800 ° C. for 4 hours. During the

Example 4

A disk produced and machined according to Example 1 was; graphitized according to Example 3 with the The difference is that it was heated to 2800 ° C for approximately 8 hours.

This extended heating time prevents cracking by shrinking and allowing more time for volatiles to escape.

Some properties of the moldings produced in this way at room temperature are:

Bulk weight 0.96 g / cm ²

Flexural strength

in grain direction,. 1.410 kg / mm ²

against the grain direction .. 0.492 kg / mm ²

Young module

in the direction of the grain 0.654 kg / mm ²

against the grain direction .. 0.281 kg / mm ²

Electrical resistance

0.005 microohm / cm in the fiber direction

against the grain. .. 0.009 microohms / cm

The objects according to the invention made of pure graphite differ from the known ones Laminates due to the lower alignment of the fibers. This disordered fiber storage is in the Photomicrograph recognizable.

The entirely made of graphite according to the invention Articles are used as a support for pyrolytic carbon for vapor deposited Tungsten and other high-temperature-resistant layers and as a base for free-standing applications Tungsten, pyrolytic carbon and graphite are suitable. The new substances can also be used in areas of low erosion, for example for parts of projectiles and missiles.

In the following table are some properties of shaped bodies according to the invention and of shaped bodies made of graphite and of bonded layered ones Graphite fabrics put together.

characteristic

Common graphite made from carbon black

the end

Petroleum coke

Graphite fabric layers

bound with carbon

Graphite bonded moldings according to the invention

charred
Fibers with
carbon
bound graph
with Koh
fuel
bound it fibers
with
graphite
bound 0.94 1.15 1.10 0.984
0.633 1.195
0.211 1.195
6.352 0.022
0.031 0.042
0.025 0.003
0.007 22.0 28.7
36.5 29.2
34.4 ' 3.7
1.8 5.6
2.7 25 to 31
9 to 18

Fibers and binders graphitized at the same time

Bulk weight,
g / cm ³

Flexural strength,
kg / mm

i. F.

g.F

Specific resistance, ohms / cm

i. F.

ε. F.

1.53

1.687
1.266

0.0063
0.0063

Thermal expansion coefficient io- ⁷ / ° c

i. F.

g-F

Thermal conductivity
kcal / h -Hi- ⁰ C

i. F.

g-F

. F. = in the direction of the grain
G. F. = against grain direction

45 to 50
45 to 50

22.2 to 29.6
22.2 to 29.6

1.58

1.828 0.700

0.0080 0.0013

25.0 35.0

119 to 178 74 to 104

1.19

1.547 0.035

0.010 0.072

24.8 41.8

1.16

2.25 0.07

0.0025 0.0130

28.3 34.7

21 to 7.4 to 0.96

1.410 0.492

0.005 0.009

26.0

Claims (9)

Patent claims: 1. Shaped body made of carbonaceous material and a carbonaceous binder, thereby characterized in that it is a fiberized disordered material as a carbonaceous material Contain charred tissue made of cellulose. 2. Shaped body according to claim 1, characterized in that it is used as a carbonaceous material contain a tissue made of cellulose which has been converted into graphite by heating. 3. Shaped body according to claim 1 or 2, characterized in that it is a charred binder contain. 4. Shaped body according to claim 3, characterized in that it is a by heating in Contain graphite transferred binder. 5. A method for the production of molded bodies according to any one of claims 1 to 4, characterized in that that a charred tissue of cellulose is frayed, the frayed pieces disordered mixes with a charring binder, molding the mixture under pressure and until charring of the binder heated. 6. The method according to claim 5, characterized in that the mixture on such Heated temperature at which the binder is converted into graphite. 7. The method according to claim 5 or 6, characterized in that there is used as carbonizable binder a phenolic resin, a pitch, an epoxy resin, furfural, furfural alcohol or mixtures of these Fabrics used. 8. The method according to claim 7, characterized in that the binder is a mixture of about 50 percent by weight phenolic resin, about 25 percent by weight furfural alcohol and about 25 percent by weight Furfural used. 9. The method according to any one of claims 6 to 8, characterized in that one part of the binder used 2 to 3 parts of the charred fabric. Considered publications: German Patent No. 1130,419; U.S. Patent Nos. 2,997,739, 2,796,331; French Patent No. 1236 007; British Patent No. 810 509. 1 sheet of drawings 609 539/395 3.66 © Bundesdruckerei Berlin