JPH059310A - Prepreg manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a prepreg having toughness as well as thermal and mechanical properties, which is particularly suitable as a structural material for aircraft. [Structure] (A) Reinforcing fiber having an elastic modulus of 200 GPa or more, (B) fibrous thermoplastic resin having an elastic modulus of 100 GPa or less, obtained by composite spinning of two or more resins, and (C) thermosetting matrix resin When manufacturing prepreg from
(C) is melted by heating and applied on a release paper,
A method for producing a prepreg in which (B) is arranged and (A) is impregnated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a prepreg for a fiber-reinforced composite material, which can impart excellent toughness to a molded product obtained from the matrix resin without impairing the excellent thermal properties and mechanical properties of the matrix resin.

[0002]

2. Description of the Related Art Composite materials having high-strength and high-elasticity fibers such as carbon fibers as a reinforcing material have been widely used mainly for sports applications because of their excellent specific strength and specific elasticity. The thermosetting resins such as the epoxy resin used as the matrix resin have various characteristics, but have a drawback of poor toughness, so that their applications have been considerably limited.

As a method for improving the defects of the thermosetting resin, a method of adding a rubber component or a thermoplastic resin is generally used, but it is necessary to add a large amount in order to obtain a sufficient toughness improving effect. As the whole viscosity increases, problems such as deterioration of processability during prepreg production, decrease of tack level of prepreg, deterioration of heat resistance and solvent resistance occur.

For example, Japanese Unexamined Patent Publication Nos. 54-3879 and 5
6-115216, JP-A-60-44334 and JP-A-1-110537, short fiber chops, chopped strands, milled fibers and spherical fine particles are localized between layers of a fiber reinforced sheet. Also in this case, problems such as a drastic reduction in prepreg tack, a complicated process, and a complicated quality control occur.

A method of inserting a kind of impact absorbing layer called an interleaf between the layers has also been proposed, for example, US Pat. No. 3,472,730, JP-A-51-58.
484, JP-A-60-63229, JP-A-60-2
There are various publications such as Japanese Patent No. 31738, but none of them is in general use because the layers are thick and the fiber ratio is low, and the heat resistance and handleability are deteriorated.

On the other hand, in the method for producing a prepreg using the fibrous thermoplastic resin of the present invention, 1) it is possible to dispose a small amount on the surface 2) it becomes easy to control the tack level of the prepreg 3) the conventional method The prepreg manufacturing process can be used as it is. 4) Quality control is easy. 5) By using the fiber obtained by composite spinning, it has various characteristics such as controlling the physical properties of the prepreg interface with great flexibility. is doing. These are effects that cannot be obtained by the conventional techniques, and are effects that can be obtained only by using the method for producing a prepreg using the fibrous thermoplastic resin of the present invention.

[0007]

The object of the present invention is to provide a prepreg for a fiber-reinforced composite material which can impart excellent toughness to a molded product obtained from the matrix resin without impairing the excellent thermal and mechanical properties of the matrix resin. To provide a manufacturing method.

[0008]

Means for Solving the Problems The gist of the present invention is: (A) Reinforcing fiber having an elastic modulus of 200 GPa or more (B) Elastic modulus 1 obtained by composite spinning of two or more resins.
When a prepreg for a fiber-reinforced composite material is produced from a fibrous thermoplastic resin (C) thermosetting matrix resin of 00 GPa or less, the thermosetting matrix resin (C) is heated and melted and applied on release paper. The prepreg is manufactured by arranging (B) the fibrous thermoplastic resin and heat impregnating the resin.

The elastic modulus (A) of the present invention is 200 GP.
As the reinforcing fiber of a or more, carbon fiber, graphite fiber, boron fiber, and other reinforcing fibers used in ordinary fiber-reinforced composite materials are used as they are, but the tensile strength is 3500 MPa.
The above carbon fibers and graphite fibers are preferably used. Among these, high strength / high elongation carbon fiber and graphite fiber having a tensile strength of 4500 MPa or more and an elongation of 1.7% or more are most preferably used. The thermosetting resin in the present invention may be any resin as long as it is a resin that is cured by external energy such as heat or light to at least partially form a three-dimensional cured product.

An epoxy resin is used as the thermosetting resin suitable for the present invention. As the epoxy matrix resin (C) in the present invention, an epoxy resin having an amine or a phenol as a precursor is preferably used. Specifically, tetraglycidyl diaminodiphenylmethane,
Triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, various isomers of triglycidylaminocresol, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol Examples thereof include novolac type epoxy resin and a mixture of two or more kinds thereof, but are not limited thereto.

The curing agent for the epoxy resin is not particularly limited, and a compound having a functional group capable of reacting with an epoxy group such as an amino group or an acid anhydride group can be appropriately used, but various isomers of diaminodiphenyl sulfone can be used. Aromatic amines represented by the body and dicyandiamide are preferably used. As the matrix resin in the present invention, it is also possible to use a resin obtained by adding a thermoplastic resin or an oligomer thereof to the above epoxy resin. As the thermoplastic resin component, those having a so-called engineering plastic skeleton such as polyimide, polyetherimide, polysulfone, polyethersulfone, and polyetheretherketone are preferable from the viewpoint of heat resistance, and a functional group capable of reacting with an epoxy resin. It is preferable that the compound has a group at the molecular end or in the molecular chain.

The amount of the thermoplastic resin added to the epoxy resin is preferably 30% by weight or less, more preferably 0 to 15% by weight. When the thermoplastic resin is used in an amount of more than 30% by weight, the viscosity of the system becomes too high, which not only causes impregnation failure during prepreg formation, but also the tack characteristics of the prepreg,
It also causes deterioration of drape characteristics. It is also possible to mix a small amount of inorganic fine particles such as fine powder silica or an elastomer with the epoxy resin.

The ratio of the reinforcing fiber (A) to the epoxy matrix resin (C) can be appropriately set according to the purpose, but the weight ratio is (A) / (C) = 60/40. The range of ~ 75/25 is particularly preferable.

As the fibrous thermoplastic resin having an elastic modulus of 100 GPa or less obtained by composite spinning of two or more resins (B), polyaramid, polyester, polyacetal,
Polycarbonate, polyphenylene oxide, polyphenylene sulfide, polyarylate, polybenzimidazole, polyimide, polyetherimide, polysulfone, polyamide, polyamide imide, etc. It is preferable to use a fiber that is shaped into a fibrous shape by a composite spinning in which a core / sheath structure, a side-by-side structure, a sea-island structure, and the like are discharged by changing the same nozzle and changing the same. Those having a functional group capable of reacting with an epoxy resin such as a phenolic hydroxyl group are particularly preferable.

As such a thermoplastic resin, in addition to polyamide, polyamideimide, etc., engineering plastics, super engineering plastics, polyamides, polyamideimides and others in which functional groups are introduced into the terminal or molecular chain by means of copolymerization or the like Engineering plastics, polymer alloys with super engineering plastics, etc. are preferably used.

The form of the fibrous thermoplastic resin obtained by the composite spinning is preferably monofilaments or a bundle thereof, but is not necessarily limited thereto. The fiber diameter is preferably 100 μm or less, and particularly preferably 50 μm or less.

The ratio of the fibrous thermoplastic resin is (C)
0 to 100 parts by weight of the epoxy matrix resin of
5 to 20 parts by weight is preferable. If it is less than 0.5 part by weight, a sufficient toughness improving effect cannot be obtained. On the other hand, if the amount exceeds 20 parts by weight, the effect of improving the toughness is not reached even if the fibrous thermoplastic resin is used, and depending on the type of resin used, the heat resistance, solvent resistance, and other properties may drop significantly. Yes,
Not good

It is important that the fibrous thermoplastic resin in the present invention exists near the outer surface of the prepreg. When it is completely buried in the center of the prepreg, sufficient toughness improving effect cannot be obtained. However, it is not preferable that the fibrous thermoplastic resin is completely raised from the surface of the prepreg, and most of the fibrous thermoplastic resin is preferably buried in the resin. Further, it is more preferable that the fibrous thermoplastic resin is present in a state in which the fibrous thermoplastic resin is evenly aligned in one direction. The alignment direction is not particularly limited and may exist at any angle with respect to the inter-reinforcing fibers, but aligning in the same direction as the reinforcing fibers is the easiest in the process. With respect to the composite-spun fibrous thermoplastic resin, the combination form of the resin is not limited at all, and any combination or form that is considered to satisfy the required performance can be adopted.

A method for producing a prepreg composed of reinforcing fibers, a matrix resin and a fibrous thermoplastic resin is, for example, a thermosetting resin which is heated and melted is coated on a release paper with a coater to a predetermined thickness, and the fibers are then applied. Prepreg for composite material by arranging thermoplastic resin and fixing the position to produce a resin film for prepreg production, and then using this to superpose and impregnate reinforcing fibers in a conventional prepreg production facility. To get There is no problem in using this method as a method for producing a prepreg obtained by arranging the fibrous thermoplastic resin on only one surface. The amount of fibrous thermoplastic resin used can be controlled easily by adjusting the number of fibers (fiber spacing) and denier. Also, since there is spacing between the fibers, the tack level of the matrix is the same as the tack level of the prepreg. Since it is reflected, the tack level of the prepreg can be easily adjusted.

[0020]

The molded product from the prepreg obtained according to the present invention is imparted with excellent toughness without impairing the excellent thermal properties and mechanical properties of the matrix resin, and further propagates the generated cracks. It is suitable for use as a structural material for aircraft, etc. because it has the property of being hard to prevent.

[0021]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the composition and spinning form are not limited thereto.

Examples 1 to 3 A matrix resin having the resin composition shown in Table 1 was coated on a release paper, and the sheath component was nylon 12 (elastic modulus of about 2 G).
Pa), the core component is polyester (elastic modulus about 15 GPa)
A resin film was prepared by arranging the core-sheath type composite yarns at 3 mm pitch. The composite yarn was a 90 denier 36 filament multifilament of nylon 12 / polyester (8/2 weight ratio).

The resin film and high-strength medium-elastic carbon fiber (MR60P manufactured by Mitsubishi Rayon, tensile strength 5600)
A unidirectional prepreg was prepared by a hot-melt method from a MPa, an elastic modulus of 310 GPa, and an elongation of 1.9%). CF basis weight of prepreg is 190 g / m ² , resin content is 34% by weight
Met. A small piece having a predetermined size was cut out from this prepreg, and after laminating, a test piece for measuring the compressive strength after impact was molded by autoclave molding (curing condition: 180 ° C. × 2 hours).

Using this test piece, SACMA (Sup
pliers of Advanced Compos
ite Materials Associates
n) Recommended Method SRM2
The compressive strength after 270 lb-in impact was measured according to -88, and the results shown in Table 1 were obtained.

Example 4 A prepreg was produced in the same manner as in Example 1 except that a multifilament in which the nylon / polyester spinning form was 1/1 side-by-side was used and the compressive strength after impact was measured. The obtained compressive strength after impact is 327MP
It was a.

EXAMPLE 5 Nylon 12 / polyester (8/2) as in Example 1 except that the composite yarn was such that polyester islands were interspersed with the sea of nylon when the yarn cross section was observed.
A prepreg was produced by using a 90 denier 36 filament multifilament (weight ratio) and the compressive strength after impact was measured. The obtained compressive strength after impact is 320M.
It was Pa.

Example 6 A prepreg was prepared in the same manner as in Example 1, except that a multifilament having a fiber component sheath made of polybutylene terephthalate (elastic modulus of about 2.5 GPa) and a core of polypropylene (elastic modulus of about 1 GPa) was used. Was manufactured and the compressive strength after impact was measured. However, the composite yarn was polybutylene terephthalate / polypropylene (5/5 weight ratio). The obtained compressive strength after impact was 313 MPa.

Comparative Examples 1 to 3 Unidirectional prepregs were produced in the same manner as in Examples 1 to 3 except that a resin film having a resin content of prepreg of 36% by weight was used. Using this prepreg, evaluation was performed in the same manner as in Example 1 without attaching fibers. The results are also shown in Table 1.

[0029]

[Table 1] YH434L: Tetraglycidylamine type epoxy resin (manufactured by Toho Kasei Co., Ltd.) ELM-100: Triglycidylamine type epoxy resin (manufactured by Sumitomo Chemical Co., Ltd.) Epicoat 828: Bisphenol A type epoxy resin (manufactured by Yuka Shell Co., Ltd.)

[Procedure amendment]

[Submission date] November 1, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

The gist of the present invention is as follows: (A) Reinforcing fiber having an elastic modulus of 200 GPa or more (B) Elastic modulus of 1 obtained by composite spinning of two or more resins.
In producing a prepreg for a fiber-reinforced composite material from a fibrous thermoplastic resin (C) thermosetting matrix resin of 00 GPa or less,
The thermosetting matrix resin of (C) is melted by heating and applied on a release paper, and the reinforcing fiber of (A) and
(B) It is to manufacture a prepreg by superposing and impregnating a fibrous thermoplastic resin .

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction content]

A method for producing a prepreg composed of reinforcing fibers, a matrix resin and a fibrous thermoplastic resin is, for example, a thermosetting resin which is heated and melted is coated on a release paper with a coater to a predetermined thickness, and the fibers are then applied. Prepreg for composite material by arranging thermoplastic resin and fixing the position to produce a resin film for prepreg production, and then using this to superpose and impregnate reinforcing fibers in a conventional prepreg production facility. To get In addition, fiber
There is no limit to the method of manufacturing prepreg containing fibrous thermoplastic resin.
It is not fixed. The amount of fibrous thermoplastic resin used can be controlled easily by adjusting the number of fibers (fiber spacing) and denier. Also, since there is spacing between the fibers, the tack level of the matrix is the same as the tack level of the prepreg. Since it is reflected, the tack level of the prepreg can be easily adjusted.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takeshi Kato             4-1-1 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi               Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Kazuya Goto             4-1-1 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi               Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Shigeru Hayashi             4-1-1 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi               Mitsubishi Rayon Co., Ltd. Product Development Laboratory (72) Inventor Takashi Akita             4-1-1 Sunadabashi, Higashi-ku, Nagoya-shi, Aichi               Mitsubishi Rayon Co., Ltd. Product Development Laboratory

Claims (2)

[Claims] 1. (A) Elastic modulus 200 GPa or more reinforcing fiber (B) Elastic modulus 1 obtained by composite spinning of two or more resins.
In producing a prepreg for a fiber-reinforced composite material from a fibrous thermoplastic resin (C) thermosetting matrix resin of 00 GPa or less,
After the thermosetting matrix resin of (C) is heated and melted and applied on the release paper, the fibrous thermoplastic resin of (B) is arranged and fixed, and then the reinforcing fiber of (A) is superposed and impregnated. A method of manufacturing prepregs characterized by being hardened. 2. The method according to claim 1, wherein the fibrous thermoplastic resin is localized on the surface of the prepreg.