JPH01320239A - Extremely short glass fiber - Google Patents

Abstract

PURPOSE:To provide extremely short glass fibers having a prescribed extremely short length, superior handleability and work efficiency and producing a significant reinforcing effect when used in a glass fiber reinforced composite material by cutting a glass strand to the prescribed extremely short length. CONSTITUTION:Monofilaments of glass fibers are stranded as usual and the resulting glass strand is continuously cut to 300-700mum length with the edge of a cutter or the like to produce extremely short glass fibers contg. fibers having 300-700mum length by >=90wt.% of all the fibers. Since most of the extremely short glass fibers are in a stranded state and a sharp length distribution is obtd., fibers are hardly scattered and satisfactory handleability and work efficiency are ensured.

Description

[Detailed Description of the Invention] [Field of Application in Business A] The present invention relates to ultrashort long glass fibers, which are particularly easy to handle, and when used in various glass fiber reinforced composite materials, exhibit extremely excellent reinforcing effects. Regarding ultra-short glass fibers.

[Prior Art] Various composite materials containing glass fiber as a reinforcing material have been put to practical use, such as short glass fiber reinforced thermoplastic resin (GFRTP), short glass fiber reinforced thermosetting resin, etc. Short glass fiber reinforced composite materials (GF
RP) is used for various purposes.

Conventionally, milled glass fibers have generally been used as short glass IA fibers to be added to such short glass fiber reinforced composite materials. Milled glass fiber
Glass Fiber) is manufactured by pulverizing long glass fiber strands or strand waste yarn using a suitable pulverizer, and the fiber length of the product is 100%.
From micrometers or less, 100 to 3001. The length of tm1 is up to 500 μm.

[Problems to be Solved by the Invention] As mentioned above, milled fibers are manufactured by pulverization, so the strands are broken into pieces and become unbound, resulting in a product in which glass fiber monofilaments are not bundled together. At present, the fibers become aggregates, and the fiber length distribution has no choice but to have a wide hemline distribution with a lot of variation.

FIG. 3 shows a schematic diagram of a micrograph (40x magnification) showing the Iafa shape of commonly provided milled fibers. Also,
The fiber length distribution is shown in FIG.

As described above, milled fibers have large variations in fiber length, so even composite materials containing milled fibers contain many fibers with lengths that do not contribute to strength, making it impossible to obtain sufficient strength. In addition, since it is an aggregate of monofilaments in which the filaments are not bundled together, it has drawbacks in terms of handling and workability, such as scattering in the air during handling and deteriorating the working environment.

Conventionally, classification has been used as a method for improving the fiber length distribution of milled fibers, but repeated classification leads to a decrease in yield and significantly deteriorates productivity. Moreover,
In this case, there is a problem of deterioration of the working environment due to scattering of the monofilament.

The present invention solves the above-mentioned conventional problems and provides ultra-short glass LA fibers that are easy to handle and work, can be smoothly supplied, and can stably produce high-quality products. purpose.

[Means for Solving the Problems] The ultra-short glass fiber of the present invention is a cut product of glass strand, and the fiber length relative to the total fiber is 300 to 700 μm.
It is characterized in that the proportion of 1 m fibers in m is 90% by weight or more.

The present invention will be explained in detail below.

The ultrashort glass fibers of the present invention can be easily obtained by continuously cutting glass strands obtained by converging glass fiber monofilaments by a conventional method into lengths of 300 to 700 μm using a cutter blade or the like. be able to.

In this case, there are no particular restrictions on the diameter, composition, etc. of the monofilament, but -a has a filament diameter of 9 to 15 mm.
It is preferable that the thickness is μm, and its composition is preferably an E glass composition as exemplified below.

E Glass composition (wt%) SiO254.0 AJ2203 15.0 CaOf7.0 Mg0 5.0 8203 B,0 Na20 0. As a sizing agent for sizing filaments such as
Usual sizing agents (adhesives) such as vinyl acetate, urethane, acrylic, etc. can be used.

The strength of the bundling is arbitrary depending on the purpose of use of the ultrashort glass fibers, and the degree of bundling can be changed as appropriate depending on the amount of sizing agent used, the bundling tool of the strand manufacturing device, etc.

There is no particular restriction on the number of bundled filaments in the strand, but in order to obtain a clean cut surface and make the fiber length uniform by cutting with a cutter blade, it is not preferable to increase the number of bundled filaments too much. When productivity is also taken into account, it is advantageous to use a bundled strand of about 100 to 200 strands.

In addition, in the present invention, the fiber length is 300 to 700 μm.
The reason for this is as follows.

That is, in the ultrashort glass fiber of the present invention, if the ia fiber length is long, for example, 1000 μm or more, the fiber length is too long to be used as a reinforcing material in RIM (resin injection molding) or the like. Furthermore, since the fibers are long, the presence of even a small amount of monofilaments causes a problem in that they become entangled and generate fluff balls, impairing supply performance.

On the other hand, if the fiber length is short, for example, 100 μm or less, the fiber becomes powdery, and although the supply efficiency is good, it tends to scatter during handling, resulting in a problem of deterioration of the working environment. Further, if the fiber length is too short as described above, a sufficient reinforcing effect cannot be obtained.

For this reason, in the present invention, the glass strand is cut into pieces of 300 to 700 μm, and the fiber length is 300 to 700 μm.
The thickness is set so that 700 μm occupies 90% or more of the total weight. In the present invention, in particular, the fiber length is 500 μm.
It is preferable that it is around m.

As described above, in the ultrashort glass fiber of the present invention, which is obtained by cutting a glass strand to a specific length, most of the monofilaments exist in a bundled state, and the weight percentage of monofilaments that are not bundled at all in the product is usually small. 10% by weight
The following is true.

Such ultrashort glass fibers of the present invention can be made into a short fiber reinforced thermoplastic composite material (GFRTP) by briblending with a thermoplastic resin, melt-kneading in an extruder, and then injection molding.
) can be obtained.

Of course, the ultrashort glass fibers of the present invention are not limited to GFRTP, but also glass short fiber reinforced composites (GFRP) of thermosetting resins such as phenolic resin, unsaturated polyester resin, diallyl phthalate resin, or other short glass fibers. It can also be effectively applied to reinforced composite materials.

[Function] Since the ultra-short glass fibers of the present invention are cut products from glass strands, most of the glass fibers are in a bundled state, which makes it difficult to use conventional milled fibers made of monofilaments, which are light in mass and easily fly up into the air. Unlike fiber, there is no problem of fiber scattering.

Moreover, since it is obtained by cutting, the fiber length distribution is sharp, and problems caused by variations in fiber length can be solved.

The ultra-short glass fibers of the present invention are provided in a state where most of the glass fiber monofilaments are bundled, but during use, this bundle is gradually dispersed in the mixing process with a matrix such as a resin. They are mixed into monofilaments and uniformly dispersed in the matrix.

[Example code] Examples and comparative examples will be described below.

Example I Glass fiber monofilament of E-glass composition (diameter 11
A glass strand obtained by focusing 200 μm) was continuously cut into 500 μm pieces using a rotating cutter blade.
Very short glass fibers of the present invention were obtained.

A schematic diagram of a microscopic photograph (20 times magnification) and fiber length distribution of the obtained ultrashort glass fibers are shown in FIGS. 1 and 2.

As is clear from FIG. 1, most of the obtained ultrashort glass fibers (approximately 97% by weight) were bundled and did not scatter during handling. Moreover, the second
As shown in the figure, the fiber length distribution had extremely small variation.

20 parts by weight of this ultra-short glass fiber and 80 parts by weight of 66 nylon were preblended, and an extruder (screw diameter 50 mm%) was used.
L/D = 28) to produce a glass fiber-containing pellet (cylinder temperature: 290 t). The obtained glass fiber-filled pellet was molded with an injection molding machine (screw diameter 35 mm, cylinder temperature 290°C) to form A
A test piece of 37M standard was prepared.

Using this test piece, various strength measurement tests were conducted. The results are shown in Table 1.

Comparative Example 1 A test piece was prepared and tested in the same manner as in Example 1, except that a milled fiber with an average fiber length of 500 μm obtained by the pulverization method was used.

The results are shown in Table 1.

It is clear from Table 1 that the extremely short glass fibers of the present invention have an extremely excellent reinforcing effect.

[Effects of the Invention] As detailed above, the ultra-short glass fibers of the present invention have a sharp fiber length distribution with most of the fibers in a bundled state, so ■ There is no problem of fiber scattering and it is easy to handle. Excellent performance and workability.

■ Sufficient product strength can be obtained because there is no variation in fiber length.

Extremely excellent reinforcing effects such as these are achieved.

Therefore, according to the extremely short glass fibers of the present invention, a glass fiber reinforced composite material with extremely high strength can be provided with excellent workability.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a micrograph (20 times magnification) showing the shape of the extremely short fibers of the present invention obtained in Example 1, Figure 2 is a graph showing the fiber length distribution, and Figure 3 is a diagram showing the shape of the ultrashort fibers of the present invention obtained in Example 1. FIG. 4 is a schematic diagram of a micrograph (magnified 40 times) showing the fiber shape of the milled fiber having an average fiber length of 500 μm, and FIG. 4 is a graph showing the fiber length distribution. Agent Patent Attorney Tsuyoshi Shigeno Figure 1

Claims (1)

[Claims] (1) A cut glass strand product in which the ratio of fibers with a fiber length of 300 to 700 μm to the total fibers is 90%.
Ultra-short glass fibers that are more than % by weight.