JPS61157335A - Apparatus for preparing fine powdery stock material in dry state by dispersing and mixing carbon staple fiber in monofilament state - Google Patents

Abstract

PURPOSE:To uniformly disperse and mix a carbon staple fiber, by arranging a lower rotor, which has a large number of fine projections provided to the surface thereof so as to leave slight gaps therebetween, below an upper rotor having a slow peripheral speed in opposed relationship so as to rotate the opposed parts of both rotors to the same direction. CONSTITUTION:Carbon fiber aggregates 6 supplied between a pair of upper rotors 1, 2 from a hopper 5 are disentangled by fine projections 4 of the upper rotor 1 having a high peripheral speed while pressed by the fine projections 4 of the upper rotor 2 having a slow peripheral speed and the greater part of said aggregates are separated into a monofilament state to be fallen downwardly. The carbon staple fibers still adhered between the fine projections 4 of the upper rotor 1 are scraped by a brush roll 9 to be passed between the fine projections 8 of a lower rotor 7 and the elastic fine wires 12 of the brush roll 9 along with carbon staple fibers fallen while sufficiently separated. At this time, the staple fibers are perfectly separated into individual fibers by the vibrated elastic wires 12 to be dropped in a mixer 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an apparatus for producing a dry fine powder raw material in which short carbon fibers are uniformly split and mixed into single fibers.

(Prior Art) Carbon fibers having a diameter of about 5 μm to 20 μm made from raw materials such as pitch, and short fibers obtained by cutting these fibers into various lengths of up to about 100 m are known.

In addition, molded products or parts such as various mortars, concrete, glass, metals, resins, etc., made by uniformly dispersing and mixing the above-mentioned short carbon fibers, have significantly increased mechanical strength without impairing heat resistance or chemical stability. It is also known to increase.

However, when the short carbon fibers are in a uniform state in the powder or fluid raw material before being shaped to make this type of product, when some vibration, shaking, stirring, or other force is applied, it appears as if short fine hairs were swept away. Like when I sent it to you,
Adjacent short fibers tend to cross and overlap each other, forming soft, cottony, nodular aggregates.

Although the adhesive bonds between the short edges of this aggregate are not very strong, they cannot be easily loosened with fingers. However, the above-mentioned properties of short carbon fibers are a major drawback when they are added to a powdered or fluid raw material before being shaped into a molded article and uniformly dispersed and mixed.

This is because if short carbon fibers are mixed into the raw material for a molded product in the form of an aggregate containing a large number of small aggregates as described above, these aggregates will be removed during subsequent stirring, kneading, and other operations of the raw material. Depending on the dispersion method used, the carbon short fibers are not separated into single fibers, and even the once separated short carbon fibers re-agglomerate into small spheres in the raw material for the molded product. This is because fibers in a uniformly dispersed state cannot be obtained.

Therefore, extremely complicated methods must be used to obtain raw materials for mortar, slate plates, cast concrete molded products, etc. in which the short carbon fibers described above are uniformly mixed. That is, an aggregate of short carbon fibers is put into a suitable liquid material such as water to be mixed with cement, or into a fluidized raw material containing cement, and is stirred little by little with a special mixer to form a uniformly dispersed solid in a fluidized state. It is necessary to undergo an operation to form a liquid mixture.

Needless to say, the above method, which can be called a wet method, is inefficient and continuous.

Recently, this type of molding material has come to be distributed as a single package containing a mixture of various solid material additives, and if necessary, it can be kneaded with water or the like to form mortar.

This is a so-called composite material premix product.

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- One solid powder/granular composite material with added short fibers
□Package products cannot be made, and even if they were made, the short carbon fibers would aggregate over time, making them unusable. This is extremely inconvenient and does not match the trends of the times.

As described above, although there are great expectations and demands for mortar containing short carbon fibers, slate boards, cement tiles, and concrete molded products due to their excellent properties, the actual implementation of these products is negligible. The current situation is that there is.

Therefore, it would be advantageous if a composite cement could be obtained in which each single fiber of short carbon fibers is relatively sufficiently separated from each other and dispersed together in a powdery solid raw material containing the above-mentioned cement powder etc. in a dry state. Similarly, it would be beneficial if short carbon fibers could be defibrated into single fibers and mixed into various molten glasses, molten resins, and uncured resin raw materials in a dry state as described above.

In order to do this, it is necessary to mechanically separate the aggregated aggregated short carbon fibers into single fibers by a so-called dry method without using a liquid medium, or to prevent the agglomeration tendency and to separate the separated single fibers. Evenly distributed size for raw materials 7. Ishi, Kaname Gaami. However, such dry defibration of short carbon fibers has been attempted by large companies, but none have succeeded.

(Objective) The object of the present invention is to provide an apparatus for obtaining a dry fine powder raw material in which short carbon fibers are uniformly dispersed and mixed in the form of single fibers.

(Structure) In order to achieve the above object, the present invention has a pair of upper rotating bodies each having a large number of fine protrusions erected at small intervals on the surface thereof. A lower rotating body with a slow circumferential speed and a lower rotary body with a large number of thin protrusions erected at small intervals on its surface is located below the upper rotating body with a slow circumferential speed. are arranged oppositely so that the opposing parts rotate in the same direction with a slight gap between the two thin protrusions, and brush rolls whose opposing parts rotate downward are arranged on both sides of the lower rotating body. The present invention is characterized by comprising a means for mixing the split carbon short fibers passed between the lower rotating body and the brush roll with a fine powder raw material. A detailed explanation will be given below based on examples. 1 is a thick-walled steel cylindrical upper rotating body with an outer diameter of 40 cm;
The width is 80 crn, and 2 is a similar upper rotating body with an outer diameter of 20 crn.
G, width 80 crn, thin protrusions 3, 4 with sharp triangular tips and no elasticity and a length of about 6 trm are fixed on the surface of the rain upper rotor 1, 20 at a pitch of 3WI, and the tips of the thin protrusions 3, 4 are They face each other with an interval of about 1W. The upper rotating body 1 is arranged to rotate counterclockwise at a speed of 400 revolutions per minute, and the upper rotating body 2 is arranged to rotate clockwise at a speed of 20 revolutions per minute. A hopper 5 is disposed above the opposing part of the pair of upper rotating bodies 1.2, and collects short carbon fiber aggregates in which short carbon fibers with a diameter of about 15 μm and a length of about 3 m are aggregated into small lumps of irregular size. 6 is included. Below the upper rotating body 2, a lower rotating body 7 having a large number of thin protrusions 8 erected at small intervals on its surface is installed, with the opposing parts facing in the same direction with both thin protrusions 4 and 8 having a slight gap or no gap. They are arranged facing each other so that they rotate. The lower rotating body 7 has an outer diameter of 20 cm, a width of 80 mm, and rotates 15 times per minute. 9 is a brush roll disposed between the upper rotary body 1 and the lower rotary body 7; 10 is a brush roll disposed between the outer sides of the upper rotary body 2 and the lower rotary body 7;
Reference numeral 11 denotes a brush roll disposed between the brush roll 10 and the lower rotary body 1, and a large number of thin elastic wires 12, 13, and 14 with a length of 2011111 are erected on the surface of each brush roll, and the tips thereof are attached to thin protrusions on the opposing parts. The roll brushes 9 are designed to intersect slightly or not to intersect, or to have a slight gap, and the roll brush 9 moves at a rate of 20 per minute.
At zero rotation, the roll brush 10 rotates at 20 rotations per minute, and the roll brush 11 rotates at 80 rotations per minute, so that both of the parts facing the lower rotating body 7 rotate downward. 15 is a mixer into which fine powder raw materials such as cement mortar and admixtures are charged.

Next, the effect will be explained. The car 5 is supplied from the hopper 5 between the 1:0 upper rotating bodies 1 and 2.

The short fiber aggregates 6 are held down by the thin protrusions 4 of the upper rotating body 2, which has a slow circumferential speed, and are loosened by the thin protrusions 4 of the upper rotary body 1, which has a fast circumferential speed, and most of them are split into single fibers. and fall downward. It was attached between the thin protrusions 3 of the upper rotating body 1.
The short carbon fibers are scraped off by the brush roll 9, and are sufficiently separated and together with the short carbon fibers falling downward, the fine protrusions 8 of the lower rotating body 7 and the elastic fine wires 1 of the brush roll 9 are formed.
When the fibers pass between the two, the vibrating elastic fine wires 12 completely separate the fibers into individual fibers, and the fibers fall into the mixer 1-5. Small pieces of short carbon fibers that have not been sufficiently separated by the upper rotating bodies 1 and 2 are pushed toward the upper rotating body 2, which has a slower circumferential speed, and are pushed toward the thin protrusions 8 of the lower rotating body 7, which has a slower circumferential speed.
While being held down by the upper rotating body 2, it is loosened by the thin projections 4 of the upper rotary body 2 and sent to the outside. When passing between the elastic thin wire 13 of the brush roll 10, the elastic thin wire 14 of the brush roll 11, and the thin protrusion 8 of the lower rotating body 7, the elastic thin wire 1 vibrates.
1, x4, the fibers are separated into single fibers one by one, and fall into the mixer 15.

Then, it is uniformly mixed into the fine powder raw materials such as cement mortar and admixtures that are put into the mixer 15.
1 may be omitted, or the fine powder raw material may be mixed by injecting the fine powder raw material into the separated and falling short carbon fibers from both sides below the lower rotary body in the mixer ○.

(Effects) According to the present invention, a pair of upper rotating bodies each having a large number of fine protrusions erected at small intervals on its surface are arranged such that the tips of both fine protrusions are left with a slight gap and the opposing parts move relative downward. A short carbon fiber aggregate feeding device is arranged above the upper rotating body, and a lower rotating body with a large number of fine protrusions erected at small intervals on its surface is placed below the upper rotating body with a slow circumferential speed. The opposing parts are arranged to face each other so that they rotate in the same direction with or without a slight gap, and brush rolls whose opposing parts rotate downward are arranged on both sides of the lower rotating body. It is equipped with a means to mix the short carbon fibers separated by passing between the brush rolls with the fine powder raw material, so the short carbon fibers have a strong cohesive force and can be made into small, cotton-like aggregates without damaging them. A fine powder raw material in a dry state can be obtained by dividing the fibers into individual fibers and dispersing and mixing them as they are.

[Brief explanation of the drawing]

The figure is a front view of one embodiment of the present invention. 1.2... Upper rotating body, 3, 4... Thin protrusions, 5.
... Hopper, 6... Carbon short fiber aggregate, 7...
・Lower rotating body, 9, 10.11...Brush roll,
12゜13.14...Elastic fine wire, 15...Mixer.

Claims (1)

[Claims] A pair of upper rotating bodies each having a large number of fine protrusions erected at small intervals on its surface are arranged so that the tips of both fine protrusions are relatively movable downward with a slight gap between them, and a carbon short piece is placed above them. A fiber aggregate supply device is installed, and below the upper rotating body with a slow circumferential speed, there is a lower rotating body with many fine protrusions erected at small intervals on its surface, with a slight gap between the two fine protrusions. brush rolls are arranged so that the opposing parts rotate in the same direction in the state, and brush rolls whose opposing parts rotate downward are arranged on both sides of the lower rotating body. An apparatus for producing fine powder raw material in a dry state in which short carbon fibers are dispersed and mixed in the form of single fibers, and is equipped with means for mixing fiberized short carbon fibers with fine powder raw material.