JPH02169B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for efficiently manufacturing a narrow unidirectional prepreg.

(Prior art) Composite materials of fiber-reinforced resins using carbon fibers as reinforcing materials have been widely used in sporting goods, automobile parts, and aerospace materials, and when used for these purposes, strands, It is often manufactured by molding a prepreg made by impregnating a strand array, a woven fabric, or the like with a resin. This prepreg includes woven prepreg, unidirectional prepreg, etc. depending on the fiber arrangement form, and usually has a thickness of 300.
The prepreg with a width of ~1500mm is cut as appropriate during molding and used by laminating it.

When manufacturing pipe-shaped articles such as golf club shafts and fishing rods, cut sheets of unidirectional prepreg are mainly used, and this sheet is wrapped around a metal core and hardened and molded. Alternatively, a pipe-shaped article is manufactured by winding a strand prepreg using a filament winding method and then curing and molding it.

(Problems with conventional methods) In the method of using unidirectional prepreg,
In many cases, the cut ends of the cut prepreg are continuous in the axial direction of the molded article, and as a result, the molded article tends to lack isotropy in the circumferential cross section. In the method of using strand prepreg for forming pipe-shaped objects, the strand prepreg has a nearly circular cross section, so the formed object tends to be thick.
Moreover, unevenness tends to occur on the surface. Further, talc and the like are added to strand prepreg to adjust tack, which causes problems such as deterioration of physical properties and limitation of resin composition. In order to eliminate these problems, it is conceivable to use a narrow sheet prepreg having a width of 3 to 200 mm and a thickness of 0.01 to 0.3 mm. The production of such narrow prepreg requires 300~
This is done by aligning 1 to 10 strands of 12,000 strands, developing them into a sheet, and impregnating them with resin.

However, according to this method, in the manufacturing process, it is necessary to cut and straighten the yarn disorder on both sides of the prepreg after resin impregnation and shape it to a predetermined width. There is a problem that a lot of resin is wasted and the production yield is poor. For example, when obtaining prepreg with a width of 3 mm, the fibers should be 1/
2 to 1/3 of the amount becomes waste, and even more resin is wasted.

Furthermore, since the resin impregnation is carried out while running a strand of a certain length, there is a problem that the production efficiency decreases as the width becomes narrower.

The present inventor has arrived at the present invention as a result of studies on methods for solving such problems.

(Structure of the Invention) The present invention is characterized in that a unidirectional prepreg is wound into a roll through a double-sided peelable polyester film, and then the obtained roll is cut in a direction of 90 degrees with respect to the roll axis. This is a method for manufacturing unidirectional prepreg.

When a narrow prepreg is manufactured by such a method, a narrow prepreg can be obtained with high productivity and a good yield.

Examples of reinforcing fibers used in the present invention include carbon fibers, glass fibers, aramid fibers, etc., and strands of 300 to 12,000 fibers are usually used.

These strands have a fiber weight of 15-300g/ ^m2
It is expanded so that it is aligned in one direction, and the width is
It is made into a sheet of 300 to 1500 mm.

The wider the width, the higher the productivity, but if the width exceeds 1500mm, uneven sheet thickness tends to occur, so considering both productivity and physical properties.
A width of 500 to 1000 mm is preferable.

The use of carbon fibers as reinforcing fibers provides the optimum properties in terms of the physical properties of the composite material and the thickness of the prepreg.

As the matrix resin for the prepreg, a thermosetting resin is preferable from the viewpoint of handleability and processability.

The fiber sheet is impregnated with resin using the hot melt method.
It can be carried out by any solvent method. The resin content of prepreg is usually 28-60% (by weight). A double-sided releasable polyester film is used as the release film. In the case of other materials, such as paper, paper dust is generated during cutting and adheres to the narrow tape surface.

Polyethylene film and polypropylene film have no stiffness, and the narrower the film, the more difficult it is to handle. Particularly during molding, when the tape is unwound, the film breaks and pieces remain in the molded product, causing a significant deterioration in physical properties.

Polyester film has a tear strength of 15Kg/mm ²
It is best to use the above. Thickness is usually 20
~50μ is used. The polyester film used has both sides coated with a release material such as silicone or polyolefin.

The prepreg, which is a fiber sheet impregnated with a matrix resin, is wound onto a paper tube with a roll diameter of 50 to 200 mm via this double-sided peelable film. If the diameter of the paper tube is small, there is a risk that waving may occur in the prepreg.

The amount of winding is preferably 100 mm or less. If the thickness exceeds 100 mm, de-centering tends to occur when cutting into narrow pieces. The preferred thickness is up to about 5 times the cutting width.

The prepreg wound onto a roll via a double-sided peelable polyester film is attached to the roll axis.
It is cut to a predetermined width in the 90 degree direction, that is, in the circumferential direction. If the cutting is performed before winding up onto a roll, defects such as fiber disorder at both ends of the cut and poor winding are likely to occur.

The cutting width is usually 3 to 200 mm, and the narrower the cutting width, the greater the effect of the present invention.

In particular, in the present invention, it is preferable to use prepreg with a fiber basis weight of 50 g/m ² or less as a tape-like prepreg with a width of 10 mm or less, so that the reinforcing fibers will not be distorted in the thickness direction even if they are wound when forming a thin pipe. A good molded product can be obtained without leaving any residue.

(Effect of the invention) According to the present invention, the following effects can be obtained.

Narrow prepreg can be obtained with good productivity.

A prepreg of a desired width can be obtained by simply cutting using a prepreg manufacturing apparatus for wide width products.

Since no paper-based release material is used, there is no generation or adhesion of paper dust during cutting, and molded products with high physical properties can be obtained.

Since a double-sided releasable polyester film is used as the release material, the strength of the release material is high.
Continuous winding at high speed during molding is possible.

Since the prepreg is tape-shaped, the reinforcing fibers are continuous, and it can be used like conventional filament winding, and it can also be used without the uneven surfaces of filament wind moldings.

Examples Phenol novolac type epoxy resin, Araldite EPN1138 (manufactured by Nippon Ciba Geigy) 70 parts by weight, bisphenol A type epoxy resin, Epicoat 1002 (manufactured by Yuka Ciel Epoxy) 20 parts by weight,
Epicote 838 10 parts by weight, dicyandiamide,
A resin composition consisting of 3 parts by weight (based on 100 parts of resin) and 5 parts by weight of 3(3,4-dichlorophenyl)-1,1-dimethylurea (based on 100 parts of resin), 7 micron single fibers, and 3000 carbon fibers were added to the resin composition. 150 fiber bundles were aligned and impregnated to form a sheet prepreg with a width of 1000 mm.
This prepreg has a resin content of 45% by weight and a fiber basis weight of
It was 30g/ ^m2 .

A 30μ thick polyester film coated with silicone release material on both sides is used as a carrier sheet to measure the outer diameter.
The sheet prepreg is placed in a 90 mm paper tube to a thickness of 30 mm.
It was rolled up into a roll to have a diameter of mm.

Next, the obtained roll is placed against the roll shaft.
Cut into 7mm wide tape in the 90 degree direction (circumferential direction) using a disc cutter to obtain 7mm wide tape prepreg 130.
I got the book.

This tape-like prepreg has a thickness of 0.21g/m.
0.03 mm, there is no melting of the film during cutting, no film fragments are mixed in, and the film has good peelability and smooth unwinding properties even during use, and the tip diameter is 5.
mm, original diameter 10mm, length 1000mm taper core 5
The operability was also good when winding at m/min.

For comparison, when we cut the above 1000mm wide sheet prepreg directly (without making it into a roll) into 7mm widths and wound it into 140 pieces, we found discontinuous cutting defects,
Due to poor winding, only 67 good quality products were obtained.

Claims (1)

[Claims] 1. A method for producing a narrow unidirectional prepreg, which comprises winding the unidirectional prepreg onto a roll via a double-sided releasable polyester film, and then cutting the obtained roll at 90 degrees to the roll axis.