JPS596186B2 - High rigidity milled fiber manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a milled fiber of high rigidity fiber, and more specifically, provides a method for highly efficiently manufacturing a milled fiber of an inorganic high rigidity fiber having an elastic modulus of 5 toss 4d or more. This is what I am trying to do.

In recent years, the applications of milled fibers, which are inorganic high-rigidity fibers such as glass fibers and carbon fibers, have become widespread. In addition to the same fields of use as glass fiber, carbon fiber can also be used as an antistatic material for various synthetic resin products, as a conductive material for electrodes and surface heating elements, and as reinforced fiber for fiber-reinforced metals. ,
Milled fibers are in great demand for a wide range of applications, including industrial materials, such as mixing with rubber, wear-resistant materials such as brake shoes and clutch plates, and sports equipment.

Conventionally, methods for producing milled fibers of high-rigidity fibers have involved the use of various types of crushers and heaters, including stamp mills, ball mills, and bipro mills, fiber beating machines such as Refurina, and other mixers with high-speed rotating blades. However, all of these methods are extremely inefficient or provide a wide fiber length distribution, making them unsatisfactory. The inventors of the present invention have developed the present invention by intensively studying the production of extremely high rigidity fibers, such as high-strength carbon fibers having an elasticity of 20 tons/1 or more, into milled fibers. That is, the present invention cuts a fiber bundle of high-rigidity fibers into short fiber bundles, then defibrates and disperses the short fiber bundles, and then collects them to form a non-oriented short fiber mat.
The present invention relates to a method for producing milled fibers of high rigidity fibers, which is characterized in that the non-oriented short fiber mat is then pulverized using a roller mill to form milled fibers.

In other words, high-stiffness fibers are strong in the direction of the fiber axis, but have extremely low strength in the direction perpendicular to the fiber axis, and are extremely brittle in that direction. If this is done, the number of crossing points, that is, the number of folding points, between the short fibers when matted becomes very large.

We have also discovered that when such a non-oriented mat is applied to a roller mill, the Calorie pressure from the rollers is concentrated as linear pressure at the intersection points, and it is extremely easy to break at the intersection points to form a single milled fiber. It is.
In other words, by defibrating the short fiber bundles, a large number of short fiber break points are created when the short fibers are made into a mat, and in combination with applying linear pressure with a roller mill, the milled fibers are made extremely efficiently. It can be easily manufactured. The roller mill used may be of any type, but is preferably a vertical type having any number of stages and pairs of pressure rollers depending on the purpose. The pressure roller can be of any type, such as a smooth roller or a grooved roller, but the first stage roller is a combination of a smooth roller and a grooved roller, and from the second stage onwards, a combination of smooth rollers is more efficient. can be integrated into milled fiber. There is no particular restriction on the number of stages of rollers, and the higher the number, the better, but from an economical point of view, two stages are usually common. The short fiber mat of high-rigidity fibers to be supplied to the roller mill has a fiber length in the range of several millimeters to several tens of millimeters, and the basis weight of the mat depends on the capacity of the roller mill, but it is preferably a high basis weight of at least 309/I or more. According to such a method, a non-oriented short fiber mat of high rigidity fibers is primarily converted into milled fibers by the first roller of a roller mill, but has a relatively wide fiber length distribution. By further processing this with the next roller, the number of fiber intersection points increases exponentially, the milled fibers become unified, and the fiber length distribution becomes uniform. Although each method has its advantages and disadvantages, either a dry method or a wet method may be employed. Next, a more detailed explanation will be given with reference to the accompanying drawings and examples.

FIG. 1 is a schematic diagram of an apparatus showing an embodiment of the present invention, in which high-rigidity continuous fibers 1, such as carbon fibers, are preliminarily cut into arbitrary short fibers using a cutter 2, and the shorter the fiber length, the better.

The defibrated short fibers 5 are uniformly dispersed in a hood 4 by an air sector 3, and the short fibers are collected on a net conveyor 9 that sucks air from below to form a non-oriented short fiber mat 6 and a roller mill 7. The fiber is pulverized to obtain milled fiber 8. In this case, if water or other appropriate liquid is simultaneously supplied to the roller mill 7 and wet grinding is performed, the milled fibers will be less scattered and the working environment will be better, but a drying step will be required. On the other hand, in the case of a dry method, it is necessary to make the roller mill a completely closed system, and although there are advantages and disadvantages of dry and wet methods, either method may be used. EXAMPLE The experiment was carried out in a dry manner using the apparatus shown in FIG.

The high-rigidity fiber has a single fiber diameter of 7 μm and a tensile strength of 2801<g.
/MTL. Using a high-strength unfocused continuous carbon fiber bundle with a tensile modulus of 25 tons/UTI and 3000 filaments,
Fiber lengths of 3, 6, 13, 27, 54 are cut using a fiber bundle cutting device consisting of a pair of cylindrical implanted rotary blade and rubber roller! It
Cut into 7IL short fibers, and defibrate and disperse the short fiber bundles using a mechanical sector with an air pressure of 2.5 kg/DG.
The fibers ranging from A to A were milled into a single milled fiber by passing through a roller mill consisting of two pairs of metal rollers. In this case, in the first stage of the roller mill, one of the rollers with a rough surface such as a roulette gave better biting properties and showed preferable results than both of the rollers were smooth. The fiber length characteristics of the obtained milled fiber were measured using an optical image analyzer, and the results are shown in Table 1. As explained above, according to the present invention, production of milled fibers, which has been difficult in the past, can be carried out extremely easily and continuously with high efficiency, and the fiber length distribution is also relatively uniform, which is extremely significant. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the apparatus method of the present invention. 1...High rigidity continuous fiber, 2...Katsuta, 3...Air sector 4...Hood, 6...Short fiber Matsuto, 7... Roller mill, 8... Milled fiber one.

Claims (1)

[Claims] 1 A fiber bundle of high-rigidity fibers is cut into short fiber bundles, and then the short fiber bundles are defibrated and decomposed, and then collected to form a non-oriented short fiber mat, and then the non-oriented short fiber mat is 1. A method for producing a milled fiber of high rigidity, which comprises pulverizing the fiber using a roller mill to form a milled fiber.