JPS636251B2 - - Google Patents

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 up to about 100 mm 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 uniformly added to 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 becomes as if the short carbon fibers are shortened. Similar to when fine hair is swept together, adjacent short fibers tend to cross and overlap each other, forming soft, cotton-like aggregates. Although the adhesive bond between each short fiber in this aggregate is not very strong, it cannot be easily rubbed 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 many small aggregates as described above, these aggregates will be removed during subsequent stirring, kneading, or other operations of the raw material. Depending on the dispersion method used, the individual fibers may not be separated, but on the contrary,
Even the short carbon fibers that have been separated once reaggregate into small spheres in the raw material for the molded product, and therefore it is not possible to obtain a state in which the short carbon fibers are uniformly dispersed as mutually separated single fibers in the raw material. It is.

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 such as water to be kneaded with cement, or into a fluidized raw material containing cement, and is stirred little by little with a special mixer to form a uniform fluid. It is necessary to undergo an operation to form a dispersed solid-liquid mixture.

It goes without saying that the above method, which can be called a wet method, is inefficient and roundabout.

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 premixed composite product.

However, due to the above-mentioned problems, it is not possible to make a one-package product of a solid powder/granular composite material containing short carbon fibers, and even if it were made, the short carbon fibers would aggregate over time, making it unusable. You won't get any more. 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 mixed with carbon short fibers, straight plates, cement tiles, and concrete molded products due to their excellent properties, their actual implementation is negligible. The current situation is that there is.

Therefore, it would be advantageous if it would be possible to obtain a composite cement in which each single fiber of short carbon fibers is relatively sufficiently separated from each other and dispersed together in a dry state from the beginning in a granular solid raw material containing the above-mentioned cement powder or the like.
Similarly, it would be of great benefit 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 using a so-called dry method without using a liquid medium, or to prevent the agglomeration tendency and leave them in the state of separated single fibers. It is necessary to add it to the raw material. 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 includes a pair of upper rotating bodies each having a large number of fine protrusions erected at small intervals on the surface thereof, and the tips of both fine protrusions are arranged facing each other with a slight gap between them. The thin protrusions of one rotary body with a slow circumferential speed hold down the small carbon short fiber lumps, and the thin protrusions of the rotary body with a faster circumferential speed perform relative movement to loosen the small pieces, and the carbon short fibers are placed above it. 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. The present invention is characterized in that it is equipped with a means for mixing the fiberized short carbon fibers 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 and a width of 80 cm; 2 is a similar upper rotating body with an outer diameter of 20 cm and a width of 80 cm; both upper rotating bodies 1 and 2 have tips on their surfaces. Sharp triangular, non-elastic thin protrusions 3 and 4 having a length of about 6 mm are fixed at a pitch of 3 mm, and the tips of the thin protrusions 3 and 4 face each other with an interval of about 1 mm. 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. 1
A hopper 5 is disposed above the opposing portion of the pair of upper rotating bodies 1 and 2, and a carbon short fiber aggregate 6 is formed by agglomerating short carbon fibers having a diameter of about 15 μm and a length of about 3 mm into small lumps of irregular size. 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 both thin protrusions 4 and 8 having a slight gap or no gap, and facing parts facing in the same direction. 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 cm, 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; 11 is a brush roll 10 and the lower rotary body 7; A large number of fine elastic wires 12, 13, and 14 each having a length of 20 mm are erected on the surface of a brush roll placed between the brush rolls, and the tips thereof are slightly intersected with the thin protrusions of the opposing portions, or are not intersected with each other. The roll brush 9 rotates at 200 revolutions per minute, and the roll brush 10 rotates at 20 revolutions per minute.
During rotation, the roll brush 11 rotates at 80 revolutions per minute, with both portions facing the lower rotating body 7 rotating 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. 1 from Hopper 5
The short carbon fiber aggregates 6 supplied between the pair of upper rotating bodies 1 and 2 are held down by the fine protrusions 4 of the upper rotating body 2 whose circumferential speed is slow, while being held by the fine protrusions 4 of the upper rotating body 1 whose circumferential speed is high. It is loosened and most of it is separated into single fibers and falls downward. The short carbon fibers still attached between the thin protrusions 3 of the upper rotary body 1 are scraped off by the brush roll 9, and are sufficiently separated and combined with the short carbon fibers falling downward to the lower rotary body 7.
When passing between the thin protrusions 8 of the brush roll 9 and the thin elastic wires 12 of the brush roll 9, the vibrating thin elastic wires 12 completely separate the fibers into individual fibers and fall into the mixer 15. The small lumps of short carbon fibers that have not been sufficiently separated by the upper rotary bodies 1 and 2 are pushed toward the upper rotary body 2 due to the slow circumferential speed, and are suppressed by the thin protrusions 8 of the lower rotary body 7 whose circumferential speed is slower. While being loosened by the thin protrusions 4 of the upper rotating body 2, it is sent to the outside. And the elastic thin wire 13 of the brush roll 10
When passing between the thin elastic wire 14 of the brush roll 11 and the thin protrusion 8 of the lower rotary body 7, the vibrating thin elastic wires 13 and 14 split the fibers into individual single fibers, which are separated into a mixer 15. fall inside. Then, it is uniformly mixed into fine powder raw materials such as cement mortar and admixtures that are introduced into the mixer 15, and does not re-agglomerate.

Note that the lower brush roll 11 may be removed, or instead of the mixer, the fine powder raw material may be injected onto the separated and falling short carbon fibers from both sides of the lower rotating body to mix them.

(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 the surface are arranged facing each other with the tips of both fine protrusions leaving a slight gap, so that one of the upper rotating bodies has a slow circumferential speed. The thin protrusions of the rotating body hold down the carbon short fiber lumps,
The thin protrusions of the rotating body with a high circumferential speed perform relative movement to loosen the small lumps, and a carbon short fiber aggregate supply device is arranged above the protrusions of the upper rotating body with a slow circumferential speed. In this method, a lower rotating body having a large number of thin protrusions erected at small intervals on its surface is arranged facing each other so that the opposing parts rotate in the same direction with a slight gap or no gap between the two thin protrusions. Brush rolls with opposing parts rotating downward are installed on each side, and a means is provided to mix the split carbon short fibers with the fine powder raw material by passing between the lower rotating body and the brush rolls, so that the agglomeration is possible. It is possible to obtain a fine powder raw material in a dry state by dividing short carbon fiber aggregates, which are strongly aggregated into small cotton fibers, into single fibers one by one without damaging them, and then dispersing and mixing them as they are. can.

[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 projection, 5
...Hopper, 6...Carbon short fiber aggregate, 7
... Lower rotating body, 9, 10, 11 ... Brush roll, 12, 13, 14 ... Elastic thin wire, 15 ... Mixer.

Claims (1)

[Claims] 1 A pair of upper rotating bodies each having a large number of fine protrusions erected at small intervals on the surface are arranged facing each other with the tips of both fine protrusions leaving a slight distance between them, and the fine protrusions of one of the rotating bodies have a slow circumferential speed. The carbon short fiber aggregates are held down by the small protrusions of a rotating body with a high circumferential speed, and the small protrusions are caused to perform relative movement to loosen the small aggregates. Below the upper rotating body, which has a slow speed, is a lower rotating body whose surface has many thin protrusions erected at small intervals.The opposing parts rotate in the same direction with both thin protrusions remaining slightly or absent for a while. Brush rolls are arranged facing each other, and the opposing parts rotate downward on both sides of the lower rotating body, and the split carbon short fibers are passed between the lower rotating body and the brush rolls and turned into fine powder raw material. A dry fine powder raw material manufacturing device that disperses and mixes short carbon fibers into single fibers, and is equipped with a mixing means.