JPS6011315A - Manufacture of prepreg - Google Patents

Abstract

PURPOSE:To produce continuously a high performance prepreg that is excellent in harmonizing property and is extremely thin, by impregnating a sheet, which sheet is made up of a plurality of groups of arranged extremly fine filaments having an average diameter of up to 6mum, with a resin. CONSTITUTION:A fed sheet, which sheet is made up of a plurality of groups 11 that have a weight per unit of 0.2+ or -0.05g/m and are made up of extremely fine filaments having an average diameter of 6mu or less, is spread by a bar 14 and is impregnated with a resin on a releasing paper 15 by a preheater 16. Thus a high performance prepreg can be produced continuously that is excellent in harmonizing property and is extremly thin.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for continuously producing ultra-thin, high-performance prepregs with excellent consistency.

[Background technology]

Prepreg, which is made by impregnating reinforcing fiber bundle sheets such as carbon fibers, glass fibers, and fully aromatic polyamide fibers with thermosetting resins such as epoxy resins, non-reactive polyester resins, and polyimide resins, can be used for leaf springs, honeycomb structural materials, etc. It is widely used as a molding material, as an industrial material for fishing rods, sports and leisure applications such as golf and badminton shafts, and as a material for aircraft, automobiles, and medical applications.

With the diversification of its uses, prepregs with various molding thicknesses have been developed, ranging from 0.05 to 0.
．． Thicknesses of 5 m are generally used, and those of different thicknesses are selected and used in combination depending on the thickness, shape, processing accuracy, and mechanical properties of the molded product.

For example, if you want to obtain a relatively thick molded product with fibers arranged in one direction, you can reduce the lamination labor by selecting a prepreg that can be finished with a thicker molding thickness, or choose a thin prepreg with fibers arranged anisotropically. In order to obtain this, for example, prepregs with a very thin molding thickness are combined and laminated.

These prepregs with various thicknesses have conventionally been manufactured by increasing or decreasing the fiber basis weight. Specifically, the thickness of the prepreg can be adjusted by changing the number of filaments or unit length weight of the fiber bundle, or by changing the number of fiber bundles. It's in control.

In general, fiber bundles with a small number of filaments are expensive and expensive, and the unit length and weight of 1000 or 2000 filaments is o.
Thin prepregs made from fiber bundles smaller than 1 sr/m result in extremely expensive prepregs, which have the drawback of being limited in usage and lacking in versatility. Therefore, as a countermeasure, a fiber bundle with a large number of filaments is expanded to make a prepreg, and generally a fiber bundle with a number of filaments of 3000 and a unit length and weight of 0.2 y/m is made. It is pressed and expanded to create prepreg with a thickness of 0.05 knots or less.

However, a prepreg having a thickness of 005w or less produced by such a method has a major drawback in that it has many openings, and as a result, a uniform molded product cannot be obtained.

[Object of the Invention] The present inventors have developed an ultra-thin prepreg fiber bundle with almost no openings, which does not have the above-mentioned drawbacks, at a low cost, that is, with a unit length weight of less than 0.15 f/m. As a result of various studies on how to produce ultra-thin prepreg without using , it was discovered that the following method can be used.

[Structure of the invention]

The gist of the present invention is to manufacture a unidirectionally aligned fiber-reinforced prepreg by impregnating a fiber bundle sheet, which is a plurality of aligned fiber bundles made of ultrafine single fibers with an average diameter of 6μ or less, with a resin. .

More specifically, the weight per unit length of the fiber bundle is 0.2±0.05 f, which is composed of ultra-fine single fibers with an average diameter of 6p or less.
/ m, it is possible to obtain an ultra-thin, high-performance prepreg that could not be obtained with conventional fiber bundles of 3000 filaments. By adopting the method of the present invention, it is less than 0.05 m, and even 0.03 m.
It becomes possible to easily manufacture prepregs with a diameter of m or less. The ultrafine fibers to be used can be wholly aromatic polyamide, glass fibers, silicon carbide fibers, etc., but it is particularly preferable to use carbon fibers.
34 and Japanese Patent Publication No. 57-42728 are used.

FIG. 1 shows a fiber opening experiment device of the present invention, and FIG. 2 shows a prepreg manufacturing device suitable for carrying out the present invention. A sheet of fiber bundle aυ fed is expanded by a bar (+4),
Preheat meter fl (on release paper (151) coated with resin)
]') is impregnated with resin and rolled up as a prepreg.

[Effect]

The fiber bundle used in the present invention is composed of ultra-fine fibers, that is, the fiber bundle has a large number of filaments even though the unit weight is the same, compared to the conventional fiber bundle composed of thick fiber diameter fibers. Fiberability and spreadability are significantly improved. This was discovered for the first time by the present inventors, and is numerically shown in the reference example.

Although it is not clear why this effect is obtained,
The smaller the diameter of the single fibers, the smaller the contact area between the fibers, which reduces the frictional force between adjacent single fibers within the fiber bundle, making it easier for the fibers to slip when subjected to the action of pushing the fiber bundle apart. It is inferred that the fibers open easily.

〔Example〕

The present invention will be specifically explained below using reference examples and examples.

Reference Example 1 In order to examine the spreadability of the fiber bundle, an apparatus as shown in FIG. 1 was used to examine the spreadability, and the results are shown in Table 1.

In the figure, (1) a U fiber bundle, (2) a fiber bundle bobbin unwinding device with a band brake, (3) a guide, 141
゜ (5) and (6) are fixed bars with a diameter of 251 FII+ for fiber opening, and (7) is a fiber bundle winding device.

The Oka experiment was conducted with a carbon fiber bundle running at a speed of 1 m/min at a tension of 500 t. As is clear from the table, it can be seen that as the diameter of the single fiber becomes smaller, the spreadability is significantly improved.

Table 1 Actual example 1 Using a prepreg sheet manufacturing apparatus as shown in Fig. 2, a fiber bundle made of carbon fibers having the diameter of divine leather fibers,
500 manufactured from release paper coated with resin film
Table 2 shows the performance of the width prepreg sheet.

In the figure, (11) is the aligned fiber bundle, ← side is the feed roll, a31 is the guide comb, I is the fixed bar for opening, 0
51 is a release paper coated with resin, (16) is a preheating plate heater for resin impregnation, a7) is a heating nip roll for resin impregnation, 081 is a prepreg winding roll, and numeral 1 is a release paper for roll retention.

In the table, Nu 1 indicates the performance of the prepreg manufactured from a fiber bundle of 3000 filaments with a molding thickness of 0.045 mm as the target, and it was found that the fiber bundle did not spread well and only a large number of openings could be obtained. It shows.

Ugly 2 and 3 show examples of the present invention, especially Ugly 3.
Molding thickness is 0.0 using ultra-fine carbon fiber of 5μ
This shows that an ultra-thin prepreg with a thickness of 3++nn or less was obtained with high properties.

Sample No. 4 was made from a commercially available fiber bundle containing 1000 filaments, and although it had the same performance as Ix obtained by the method of the present invention, it was very expensive in terms of cost.

〔Effect of the invention〕

By adopting the method of the present invention, it is possible to continuously produce high-performance ultra-thin prepreg sheets at low cost. For example, when used in the circumferential direction of a tubular molded product such as a fishing rod, It is possible to obtain a product with greatly improved crushing strength without changing the

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the apparatus used to examine the spreadability of the fiber bundle of the present invention, in which (1) is the fiber bundle, (2) is the unwinding device, (4) to (6) are the bars, (7) shows a winding device. FIG. 2 is a schematic diagram of an apparatus suitable for producing the prepreg sheet of the present invention, where LQll is a fiber bundle, (12+ is a feed roll, (14) is a bar, Q7) u is a heating nip roll, and discharge is a take-up roll. .

Claims (3)

[Claims] (1) A method for manufacturing unidirectionally aligned fiber-reinforced prepreg, which is characterized by impregnating a fiber bundle sheet, which is made by aligning a large number of fiber bundles made of ultrafine single fibers with an average diameter of 6μ or less, with a resin. (2) Is the fiber bundle 0.2±0.05? /m. (3) A method for producing a prepreg according to claim 1, characterized in that the ultrafine single fibers are made of carbon fibers.