JPS6252139A - Modified cross section glass fiber and production thereof - Google Patents

Abstract

PURPOSE:To strengthen entanglement between fibers and remarkably improve the strength of a composite material when used as a reinforcing material thereof, by constituting glass fibers only from homogeneous glass and periodically changing the cross-sectional shape and cross-sectional area in the longitudinal direction. CONSTITUTION:Molten glass 5 in a bushing 4 having an orifice plate 3 at the bottom thereof is discharged through many orifices 6 and spun into many filaments 1. A binder is then applied to the resultant filaments 1 by an applicator 7 and then bundles into one strand 9 by a bundling tool 8. The strand 9 is then traversed by a traversing device 10 and wound onto a winding tube 11. Thereby, the aimed glass fibers, constituted of only homogeneous glass and having a cross-sectional shape periodically varying between an egg apple and circle. The ratio of the maximum cross-sectional area to the minimum cross-sectional area is within 2-15 range.

Description

DETAILED DESCRIPTION OF THE INVENTION INDUSTRIAL APPLICATION J Field of the Invention The present invention particularly relates to glass fibers suitable for use as reinforcing materials mixed into thermosetting resins, thermoplastic resins, etc., and a method for producing the same.

``Conventional technology J Glass in general!! Miscellaneous uses a bushing that has an orifice plate with a large number of circular orifices on the bottom surface, and the molten glass in the bushing flows out through the large number of orifices to form a large number of filaments. , these filaments are assembled into one or several strands and wound up. Each filament of glass fiber thus manufactured has a cross-sectional shape close to a perfect circle and a uniform thickness in the longitudinal direction. When used as a reinforcing material, a treatment agent is generally attached to the surface to provide interfacial adhesion between glass and resin.

"Problems to be Solved by the Invention" In recent years, there has been a strong desire to improve the strength of composite materials of resin and glass fibers, and to improve the tear strength of vapor made from glass fibers, but conventional general methods Since the glass fibers manufactured by the above-mentioned glass fibers have a cross-sectional shape that is constant in the longitudinal direction, almost a perfect circle, and a smooth surface, when used as a reinforcing material, the fibers are weakly intertwined with each other and cannot fully satisfy the above requirements.

To solve this problem, refractory particles with a diameter several times the diameter of the glass fibers are arranged at appropriate intervals in the longitudinal direction of the glass fibers, and the surface of the glass fibers is made uneven, making it easier for the fibers to become entangled with each other. Fibers and their manufacturing methods were published in 1974.
This is proposed in Japanese Patent No. 42259. However, the glass fiber described in this publication has an extremely complex structure and is difficult to manufacture. Therefore, an object of the present invention is to provide a glass fiber that has a simple structure and is easy to manufacture, as well as a method for manufacturing the same, which can strengthen the reinforcing effect when used as a reinforcing material for a composite material. That is.

"Means for Solving the Problems" The glass fiber of the present invention that achieves the above object is characterized in that it is composed only of homogeneous glass and that its cross-sectional shape and cross-sectional area change periodically in the longitudinal direction.

Furthermore, the method of the present invention for producing the above-mentioned glass fibers uses an orifice plate consisting of a plurality of orifice groups each having a plurality of orifices arranged close to each other in a symmetrical relationship, and spins one filament for each group. , the spinning conditions are adjusted so that the orifice for spinning the filament sequentially and repeatedly moves from one orifice in the group to another adjacent orifice.

When two orifices constitute one group, it is preferable to form a conical recess in which the exits of the two orifices open symmetrically to each other on the lower surface of the orifice plate. moves back and forth between the orifices.

1 when configuring 1 group with 3 or more orifices
A group of orifices is arranged at equal intervals on the circumference, and the outlets of these orifices are open, and a conical convex portion having an apex that coincides with the center of point symmetry of the outlet is formed on the lower surface of the orifice plate. Preferably, in this case the filaments circulate circumferentially within the group to successively adjacent orifices.

"Function J" The cross-sectional shape and cross-sectional area of the glass material of the present invention change periodically in the longitudinal direction, and the bump-like bulges formed at appropriate intervals in the longitudinal direction prevent slippage between the material. Because it stops, the entanglement can be strengthened.

Furthermore, the filament transfer in the glass fiber manufacturing method of the present invention occurs as the molten glass flowing out of the orifice exit forming the filament joins with the molten glass flowing out to the adjacent orifice exit as it becomes larger. Each time this transition occurs, the filament entrains the merged molten glass and changes its cross-sectional shape and area.

"Example" FIG. 1 shows an example of the deformed glass fiber of the present invention, in which the filament 1 basically has a normal circular cross section as shown in FIG. 2B
As shown in the figure, a hump 2 having an "eggplant"-shaped cross section is formed. The glass fiber of the present invention can be made into various shapes other than the shape shown in Figure 1 according to the manufacturing method described later, but all are characterized by periodically changing cross-sectional shapes and cross-sectional areas, and the maximum cross-sectional area is Preferably, the area ratio of the area portion to the minimum cross-sectional area portion is within the range of 2 to 15.

When this ratio is smaller than 2, the desired entangling effect cannot be obtained, and when it is larger than 15, the fibers often break during winding or post-processing steps.

The above glass fiber of the present invention can be manufactured by the method described below. FIG. 3 is a schematic front view showing the operating state of the apparatus for manufacturing glass U & fibers of the present invention, in which molten glass 5 in a bushing 4 having an orifice plate 3 at the bottom flows out through a number of orifices 6 and a number of filaments 1 After being applied with a sizing agent by an applicator 7, the fibers are spun into a single strand 9 by a concentrator 8. The strand 9 is traversed by a traverse device 10 and wound onto a winding tube 11 .

FIG. 4 is a plan view showing a portion of the lower surface of an embodiment of the orifice plate 3 used in the apparatus of FIG. 3 for producing the glass fiber of FIG. 1 according to the method of the present invention. The orifice plate 3 has an array of circular orifices 6 in pairs, and the two orifice outlets of each pair of these orifices 6 are formed by cutting into the lower surface of the orifice plate 3, as shown in FIG. Formed conical recess 1
2 and open facing each other. This orifice plate is substantially the same as the orifice plate developed for automatic regeneration of the cutting orifice and disclosed in Japanese Patent Application No. 149849/1984, but the present invention allows the spinning temperature to be changed from the automatic regeneration of the earlier application. The winding speed, orifice size, A-refice spacing, and other factors are adjusted so that the spun filament exhibits the phenomenon described below.

That is, under the spinning conditions according to the present invention, as shown in FIG. Only 13 are formed. As shown in FIG. 7, when the glass droplet 13 at the right orifice outlet reaches a certain size, the molten glass at both orifice outlets merge as shown in FIG.
Book filament 1 is now spun. Next, in the present invention, this filament is not separated into two, but moves away from the left-hand orifice and moves to the right-hand orifice as shown in FIG. Droplets are formed, and the left and right orifices in FIG. 6 are exactly interchanged. Then, as the droplet formed at the left orifice exit becomes larger, the molten glass at the right orifice exit joins and the filament moves to the left again, and thus the filament moves back and forth between the left and right orifices at certain time intervals, with each migration. The fused molten glass is brought in to form humps as shown at 2 in FIG. 1 at appropriate intervals in the longitudinal direction. Figure 10 is the fourth
This is a photograph showing the cross section of a strand made by focusing a large number of filaments spun using the orifice plate shown in the figure, and it can be seen that there are knobs with an ``eggplant'' cross section mixed in with the filaments with a circular cross section.

FIG. 11 shows the orifice arrangement of another embodiment of the orifice plate used in the method of the invention, one group of eight orifices 6a, 6b, 6c.

6d, 6e, 6f, 6(], 6h, are arranged at equal intervals on the circumference, and these are point symmetrical around the apex of the conical convex portion 14 protruding from the lower surface of the orifice plate, as shown in FIG. In this embodiment, for example, the filament formed in the orifice 6a moves to the orifices 6b and 6c one after another at short time intervals, and each time it moves, it brings in the fused molten glass and creates a hump. Form.

In Table 1, as shown in FIG. 13, two orifices 6' and 6' that open into a conical recess 12', similar to the orifice plate in FIG. 4, are grouped.
, 6', the results of an experiment for manufacturing glass fiber according to the method of the present invention using an orifice whose cross-sectional shape was changed to an oval shape are shown.

The glass shavings obtained through this experiment! The grain had bumps roughly in the shape shown in Figure 1 at the intervals shown in Table 1. In this table, the convergence time is the time from when the filaments merge until the next transition occurs, and the interval between the bumps is determined by the confluence time and the winding speed. Although it is quite long, one strand is quite short. For example, if a strand of 800 filaments is formed using an 800-hole orifice plate, and the spacing between the nubs of each filament is 7 m, the strand will contain one nub at an average Q of 9 cm. Become.

The tensile strength of FRP using these strands as a reinforcing material was improved by 10 to 15% compared to conventional FRP.

The method of the present invention was tested using the orifice plate shown in FIG. 4 having orifices and recesses having the dimensions and shape shown in Table 2, and the results shown in Table 2 were obtained.

The method of the present invention was tested using the orifice plate shown in FIGS. 11 and 12, which has 8 orifices and 1 convex part as one group with the dimensions and shape shown in Table 3. The results are shown in Table 3. Got the results.

Table 3 shows 81 per group in Figures 11 and 12.
[! The embodiments with orifices in it shown in FIGS. 4 and 5 or in FIG. 13 show that filaments with significantly shorter nub spacing are obtained compared to the embodiments with two orifices per group. ing.

Although the embodiments described above are preferred embodiments, it is possible to use two orifice plates having a flat lower surface without forming recesses or protrusions on the lower surface of the orifice plate.
It has been found that the present invention can also be practiced using orifice plates having groups of three or more orifices.

Furthermore, in the embodiment of FIGS. 4 and 5, each of the two orifices in one group is replaced with three and four small-diameter orifices adjacent to each other as shown in FIG.
The molten glass flowing out from one orifice set always coalesces and is spun into a filament with a triangular cross section, and the molten glass flowing out from the other four orifice sets always coalesces and is spun into a filament with a square cross section. Furthermore, by appropriately adjusting the filament so that it reciprocates between both sets of orifices, it is possible to produce a filament whose cross-sectional shape changes alternately between a triangle and a square, and where a hump with an increased cross-sectional area is formed at the point of change. It is possible.

In addition, in the embodiments of FIGS. 4 and 5, one group of 2
As shown in Fig. 15, the spinning filament is made to have different diameters as shown in FIG. It is also possible to produce knurled filaments with an increased cross-sectional area.

"Effects of the Invention" As explained above, according to the present invention, it is possible to obtain glass fibers that are composed only of homogeneous glass and whose cross-sectional shape and cross-sectional area change periodically in the longitudinal direction. When used as a reinforcing material for materials, the strength of the composite material is significantly improved compared to conventional composite materials using glass fiber as a reinforcing material, and the manufacturing method thereof is also relatively simple.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the appearance of an example of the deformed glass fiber of the present invention. Figures 2A and 2B are 8-A in Figure 1, respectively.
They are a sectional view and a BB sectional view. FIG. 3 is a front view showing an outline of the operating state of the apparatus implementing the present invention. FIG. 4 is a plan view showing a part of the lower surface of an embodiment of an orifice plate used in the method of the present invention;
FIG. 5 is a sectional view taken along the line v-v in FIG. 4. Figures 6 to 9
The figure is a sectional view illustrating the state of filament transfer when producing the glass fiber of the present invention using the orifice plate of FIG. 4. FIG. 10 shows the orifice pre of FIG. FIG. 11 is a plan view showing the orifice arrangement of the orifice group of another embodiment of the orifice plate used in the method of the present invention, and FIG. 12 is the xn-
It is a sectional view x'ii. FIG. 13 is a plan view showing a modification in which the circular orifice of the orifice plate shown in FIG. 4 is replaced with an oval orifice. FIG. 14 shows that each of the pair of orifices in each group of FIG.
FIG. 4 is a plan view showing an embodiment configured with four small-diameter orifice groups. FIG. 15 is a plan view showing an embodiment in which the diameters of the pair of orifices in each group of FIG. 4 are made different in order to form glass fibers having alternating diameters. 1...Glass l1ft (filament), 2...
...Knob, 3 ... Orifice plate, 6.6', 6a-6h ... Orifice, 12
．． 12'...concavity, 14...protrusion,

Claims (8)

[Claims] (1) A glass fiber characterized by being composed only of homogeneous glass and having a cross-sectional shape and cross-sectional area that change periodically in the longitudinal direction. (2) The glass fiber according to claim (1), wherein the cross-sectional shape periodically changes between an "egglet" shape and a circular shape. (3) The glass fiber according to claim (1) or (2), wherein the ratio of the maximum cross-sectional area to the minimum cross-sectional area is in the range of 2 to 15. (4) In a method for manufacturing glass fiber using an orifice plate consisting of a number of orifice groups, each group being a plurality of orifices arranged close to each other in a symmetrical relationship, one filament is spun for each group, and the filament is The spinning conditions are adjusted so that the orifice through which the fiber is spun moves sequentially and repeatedly from one orifice to another adjacent orifice in the group, and the cross-sectional shape and cross-sectional area change periodically in the longitudinal direction. Glass fiber manufacturing method. (5) The method for producing glass fiber according to claim (4), wherein each group includes two orifices and the filament moves back and forth between the two orifices. (6) The orifice plate has a conical recess on the lower surface in which the outlets of the two orifices of each group open symmetrically with each other.
5) The method for producing glass fiber as described in item 5). (7) Each group includes three or more orifices equally spaced on the circumference, and the filament transitions circumferentially to adjacent orifices one after another. The method for producing glass fiber described in Section 1. (8) A patent claim characterized in that the orifice plate has a convex lower surface in which the outlets of three or more orifices in each group are opened and has an apex that coincides with the center of point symmetry of the outlets. A method for producing glass fiber according to item (7).