JPS6126508B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for efficiently producing cut glass fibers of high quality. Currently, cut glass fibers are used in large quantities as reinforcing materials for various reinforced plastic products, raw materials for nonwoven fabrics such as glass paper, and the like. The conventional method for producing cut glass fibers is to use a cutting device that consists of a roller section made of rubber, synthetic resin, etc., and a barrel section that rotates while facing and pressing against the roller and has knife edges provided at regular intervals. There is a method of supplying glass fiber to the joint between the roller part and the barrel part. In this manufacturing method, the glass fiber is cut by bending it with the edge of a knife, so during manufacturing, miscuts may occur due to wear of the blade edge, loss of balance between the contact pressure between the roller surface and the barrel surface, etc. It has the problem that it tends to contain substances. Another problem is that the cut glass fibers always contain chips of rubber and synthetic resin, which are generated when the roller is cut with the edge of the knife. In this way, when miscut glass fibers whose cut length is longer than the specified length are used as reinforcing materials for various reinforced plastic products, the kneading workability of the resin and glass fibers during molding becomes poor; When glass paper or the like is produced using fibers by a papermaking method or the like, there is a drawback that the state of dispersion of the glass fibers in the dispersion medium deteriorates significantly, making it difficult to obtain homogeneous glass paper.
Additionally, if chips of rubber, synthetic resin, etc. are contained in glass fibers, reinforced plastic products reinforced with glass fibers and glass paper made from glass fibers may become stained or have electrical insulating properties. It also has the fatal drawback of worsening. Recently, a fiber cutting technique that can solve this problem of miscutting and chip inclusion has been developed, in which the fiber bundle is wound around a force-driven rotor having a plurality of radially arranged knife edges, and the fiber bundle is kept at a certain distance from the knife edges. A method has been developed in which the fiber bundle wound around the rotor is pressed against the knife edge using a rotatable pressure roller installed with a rotor. Since it has extremely high hardness compared to organic fibers, it has problems in that the knife edge and the knife itself are easily destroyed, and the cutting workability is extremely poor, making it virtually impossible to manufacture. The inventors of the present invention have conducted intensive studies to find manufacturing conditions that provide good cutting workability, and have found that manufacturing is possible only under limited conditions, leading to the present invention. That is, the glass fiber bundle is wound around a rotor that has a plurality of radially arranged knife edges and is forcibly driven, and is then wrapped around the rotor by a rotatable presser roller provided at a constant distance from the knife edges. When cutting glass fiber bundles by pressing them against the knife edge, production efficiency is improved by supplying a total of 200 to 50,000 tex of glass fiber bundles and rotating the rotor at a circumferential speed of 5 to 300 m. Does not contain miscut parts or chips of rubber, synthetic resin, etc.
It has been discovered that high quality cut glass fibers can be produced. In the manufacturing method of the present invention, when supplying glass fiber bundles smaller than 200 tex in total, the amount supplied is too small and the maximum circumferential speed of the rotor is limited (if the circumferential speed is higher than 300 m/min, the knife blade will frequently destroy it and spend time replacing the knife blade)
Because of this, production volume does not increase. Also, in total
When supplying a glass fiber bundle of more than 50,000 tex, no matter how much you reduce the peripheral speed of the rotor, cutting will be strained and the knife blade will frequently break.
The amount of glass fiber supplied will be
A total range of 200 to 50,000 tex, more preferably 500 to 20,000 tex is desirable. in total
200~200~50000 tex range glass fiber bundles
By dividing the fibers into multiple fiber bundles of 10,000 tex and feeding them to the rotor, cutting efficiency is further improved. In the manufacturing method of the present invention, if the circumferential speed of the rotor is lower than 5 m/min, there is an upper limit to the amount of glass fiber bundles supplied (if it is higher than 50,000 tex, the knife blade will break frequently and it will take time to replace it). Therefore, the production volume will not increase, and 300
If the speed is faster than m/min, the knife blade will frequently break as described above, so the peripheral speed of the rotor is desirably in the range of 5 to 300 m/min, more preferably 50 to 150 m/min. The present invention will be specifically explained below with reference to Examples and drawings. Embodiment FIG. 1 is a schematic plan view of a cutting device used in this embodiment, and FIG. 2 is a side sectional view taken along the line E--I' in FIG. A glass fiber bundle 1 of a predetermined thickness is held down and fed between a roller 2 and a forcibly driven rotor 4 having knife blades 3 radially spaced at 10 mm intervals, and cut for 10 hours at a predetermined rotor circumferential speed. During the work, the amount of glass fibers that could be cut, the number of times the knife blade broke, and the quality of the cut glass fibers (number of miscuts, presence of foreign matter) were inspected and evaluated, and the results are shown in Table 1. In addition, as a comparative example, a conventional method for cutting glass fiber bundles (using a cutting device consisting of a rubber roller section and a barrel section equipped with knife edges at 10 mm intervals that rotates while facing and pressing against the roller) The quality of the cut glass fibers (number of miscuts, presence of foreign matter) was evaluated after continuous cutting for 10 hours, and the results are also shown in Table 1.

[Table] From Table 1, when manufactured under the manufacturing conditions of experiment numbers 1 to 4 of the example, under the manufacturing conditions of experiment numbers 1 and 2 of the comparative example (manufacturing conditions outside the scope of claims of this specification). It can be seen that the amount of glass fiber that can be cut is significantly greater than in the case of manufacturing because the number of times the knife blade breaks during continuous cutting work for 10 hours is extremely small. In addition, compared to the glass fibers cut by the conventional cutting method using a cutting device consisting of a rubber roller part and a barrel part with knife blades at 10 mm intervals that rotate while being in pressure contact with the roller, the experiment of the example It can be seen that the glass fibers manufactured under the manufacturing conditions Nos. 1 to 4 do not contain foreign matter such as rubber debris and do not contain miscut portions.

[Brief explanation of the drawing]

FIG. 1 is a schematic plan view of a glass fiber cutting device used in an example of the present invention. Second
The figure shows a side sectional view taken along the line E--I' of FIG. Explanation of symbols 1... Glass fiber bundle, 2... Press roller, 3... Knife blade, 4... Rotor, 5... Space between blades.

Claims (1)

[Scope of Claims] 1. A rotatable presser having a plurality of radially arranged knife edges, which is arranged at a constant distance from the knife edges while winding a glass fiber bundle around a forcibly driven rotor. When the roller presses the glass fiber bundle wrapped around the rotor against the knife edge and cuts it, the total amount of the glass fiber bundle is cut.
It is characterized by supplying in the range of 200 to 50,000 tex (a unit of thickness, representing the weight in grams per 1,000 m) and rotating the rotor at a circumferential speed in the range of 5 to 300 m/min. Glass fiber manufacturing method. 2. The method for producing cut glass fibers according to claim 1, characterized in that the glass fiber bundle is divided into a plurality of glass fiber bundles having a size of 200 to 10,000 tex and supplied.