JP2002348390A - Prepreg sheet and fiber-reinforced plastic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FRP molding having excellent mechanical strengths and improved friction characteristics and a prepreg sheet which can be used for such a molding. SOLUTION: This prepreg sheet 1 comprises a web sheet 3 and a curable resin 5. The web sheet 3 is a sheet-like web comprising PTFE fibers and is impregnated with the curable resin 5. A part of the web sheet 3 is arranged on at least one surface of the prepreg sheet 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber-reinforced plastic molding, and more particularly to a fiber-reinforced plastic molding using a web made of polytetrafluoroethylene fibers. Further, the present invention relates to a prepreg sheet used for such a molded article.

[0002]

2. Description of the Related Art Fiber reinforced plastics (FRP)
Can be obtained by impregnating, laminating, curing, etc. various kinds of fibers such as glass fiber, aramid fiber, boron fiber, epoxy resin, unsaturated polyester resin, etc., and formed into a desired shape. FRP molded articles are used for various purposes.

[0003] Such an FRP molded product may be used as a sliding member such as a disk tray of a disk reproducing device mounted on a personal computer, audio, or the like. In such a sliding member, a technique for reducing a friction coefficient of a sliding surface has been proposed so as to endure repeated sliding.

This technique is used, for example, when manufacturing an FRP molded product, for example, using polytetrafluoroethylene (hereinafter, PTF).
The fine particles of E) are blended in a curable resin, whereby the friction of the surface of the obtained molded article is reduced.

[0005]

However, in this technique, when the blending amount of PTFE particles is increased in order to further improve the sliding characteristics, the mechanical strength of the curable resin layer is reduced and the curable resin layer becomes brittle. Occurs.

According to the study by the present inventors, such a problem is caused by the fact that each of the PTFE particles is independently present in the curable resin, and the It was found that the adhesion was poor.

An object of the present invention is to provide an FRP molded article having excellent mechanical strength and improved friction characteristics, and a prepreg sheet that can be used for such a molded article.

[0008]

The prepreg sheet according to the first aspect includes a web sheet and a curable resin. The web sheet is a sheet-like web made of PTFE fiber. The curable resin is impregnated into the web sheet. In the prepreg sheet, a part of the web sheet is disposed on at least one surface.

A web sheet used as a base material of the prepreg sheet is made of PTFE fibers (for example,
This is a web formed by assembling a large number of PTFE staple fibers (described later) into a sheet shape.

In such a prepreg sheet obtained by impregnating a curable resin into a web sheet, due to the bonding force between PTFE fibers, the adhesiveness with the curable resin is lower than in the conventional case where PTFE particles are added. As a result, the mechanical strength of the curable resin layer is improved. On the other hand, at least one surface of the prepreg sheet has P
Due to the location of the TFE fibers, the coefficient of friction of the surface is reduced. That is, in the prepreg sheet, the mechanical strength is improved and the low friction performance on the surface is maintained.

This prepreg sheet is further laminated, for example, with another prepreg sheet and integrally molded to further increase the strength, thereby obtaining an FRP molded article usable as a sliding member having a low friction coefficient. be able to.

[0012] The prepreg sheet according to claim 2 is the prepreg sheet according to claim 1, wherein the web sheet is
The basis weight is 25 g / m ² or more and 250 g / m ² or less. Here, particularly when such a web sheet is used, a prepreg sheet excellent in mechanical strength while maintaining a low coefficient of friction is to be obtained.

[0013] The prepreg sheet according to claim 3 is the prepreg sheet according to claim 1 or 2, wherein
The fibers have branches and / or loops. When the PTFE fibers constituting the web have branches and loops,
Since the bonding force between the fibers is increased, it is more preferable to use one having such a structure. Therefore, this prepreg sheet is intended particularly for a case where the PTFE fiber has a branch or a loop, and in such a case, the mechanical strength is improved and the surface has a low friction coefficient.

According to a fourth aspect of the present invention, there is provided an FRP molded body including a first prepreg sheet and a second prepreg sheet. The first prepreg sheet is the prepreg sheet according to any one of claims 1 to 3. The second prepreg sheet has at least one sheet laminated on the first prepreg sheet, having a sheet-like substrate made of glass woven fiber and a curable resin impregnated in the substrate. In the FRP molded body, a part of the web sheet is disposed on the surface on the first prepreg sheet side.

By using the prepreg sheet according to any one of claims 1 to 3, the FRP molded article has a low coefficient of friction on the surface and is more mechanically slid than a conventional sliding member to which PTFE particles are added. Strength has been improved.

Such a FRP molded body is a sliding member requiring low friction and mechanical strength, for example, the above-mentioned disc tray or a sill member such as a dash box, a bran, a shoji, etc. mounted on a passenger car. Etc. can be suitably used.

The FRP molded article according to claim 5 is the FRP molded article according to claim 4, wherein the second prepreg sheet is
It is composed of a plurality of prepreg sheets. In this FRP molded article, the strength of the entire molded article is further improved by laminating a plurality of prepreg sheets.

[0018]

FIG. 1 shows a prepreg sheet 1 to which an embodiment of the present invention is applied.

The prepreg sheet 1 includes a web sheet 3 and a curable resin 5. Websheet 3
Is a web formed by assembling a large number of PTFE staple fibers processed into a sheet.

The staple fiber can be produced by emulsion polymerization of tetrafluoroethylene (TFE), followed by emulsion spinning of the aqueous dispersion and baking, and baking, stretching and scraping a PTFE film. Or a method of baking, stretching, splitting, cutting, or the like a PTFE film.

The staple fiber may be produced by a method in which a staple fiber having a branch, a loop, or the like has branching, a loop, or the like, because the staple fiber has excellent confounding properties and difficult hair removal. Is preferred. That is, a method is preferred in which the PTFE film is baked or semi-baked, stretched, rubbed with a high-speed rotating needle blade roll, and defibrated.

Further, as a method for producing a staple fiber, a method including semi-firing a PTFE film is more preferable. The reason for this is that the staple fiber has a large draw ratio (though it is obtained by firing, it is 3 to 6).
This is because the weight of the web layer 5 can be reduced because a material having a small specific gravity can be obtained, and the self-adhesiveness is easy to be exhibited.
This is because it is easy to obtain one having excellent smoothness.

The web sheet 3 made of such staple fibers has a basis weight of 2 in the present embodiment.
5 g / m ² or more and 250 g / m ² or less. The web sheet 3 is entangled by a method such as a water jet needle or a needle punch in order to improve the strength of the web.

The curable resin 5 is a resin impregnated in the web sheet 3. Various additives such as a curing agent, a curing accelerator, an epoxy diluent, and a curing agent diluent are added to the epoxy resin at a predetermined mixing ratio. It is a varnish added.

The curable resin 5 is used as the web sheet 3
Is in a state where a part of the web sheet 3 is arranged on the surface. As described above, since the PTFE fibers having low friction are located on the surface, in the prepreg sheet 1, the surface friction coefficient is suppressed to be low. On the other hand, this prepreg sheet 1
Since the PTFE fibers are bound together and the adhesive strength between the web sheet 3 and the curable resin is increased, the mechanical strength is improved. That is, the prepreg sheet 1 has a predetermined strength as compared with the case where the PTFE particles are added, while the friction characteristics of the surface are improved.

The web sheet 3 is not limited to one located on one side as shown in FIG. 1, but may be located on both sides. [FRP Molded Body] FIG. 2 shows an FRP molded body 11 to which an embodiment of the present invention is applied, comprising: a first prepreg sheet 1;
And four second prepreg sheets 21.

The first prepreg sheet 1 is the prepreg sheet 1 described in the above embodiment. The second prepreg sheet 21 is a prepreg sheet having glass woven fiber as a base material, and is laminated on the first prepreg sheet 1. The second prepreg sheet 2 includes a base material 23 and a curable resin 25. In the present embodiment, a total of four prepreg sheets are used as the second prepreg sheets 21, but the number is not particularly limited.

The curable resin 25 is to be impregnated into the base material 23 and, like the curable resin 5 of the above embodiment, a curing agent, a curing accelerator, an epoxy diluent, a curable diluent is added to the epoxy resin. A varnish to which various additives such as varnish are added. In the curable resin 25, the impregnation of the glass cloth is easier than the impregnation of the web sheet 3 described above. Therefore, the epoxy diluent is used in a smaller amount than the epoxy diluent of the embodiment. It is preferred that

Then, the four second prepreg sheets 21
Is laminated on the first prepreg sheet 1 such that the surface on which the web sheet 3 is located is the outermost layer. In addition,
After lamination, the surface of the first prepreg sheet may be further cut or polished to further reduce the surface friction coefficient.

In the FRP molded body 11 configured as described above, the presence of the web sheet 3 on the outermost layer lowers the friction coefficient on the surface, and the web sheet 3 and the curable resin 5 are adhered. The mechanical strength has been improved. Further, in the present embodiment, the strength is further increased by laminating the second prepreg sheet 21.

Therefore, the FRP molded body 11 is suitable for use as a sliding member requiring low friction and mechanical strength. Applications of the sliding member include, for example, a disk tray of a disk reproducing device provided in a personal computer and an audio device, a tape storage box of a VCR, a lid portion of a dash pox provided in a passenger car, and a bottom surface of furniture and the like. Flooring materials, sill members such as bran and shoji, various types of storage, transport boxes, etc., but when used in any of them, they have excellent sliding effect and durability due to the low friction performance of the surface. Become.

[0032]

EXAMPLES [Preparation of Prepreg Sheet] As the base material 3 of the first prepreg sheet 1, a web sheet (having a basis weight of 100 g / m ² ) in which PTFE staple fibers having a branched structure were entangled was prepared. In addition, as the base material 13 of the second prepreg sheet 21, a plain-woven glass cloth (thickness: 0.2 mm) was prepared.

Each of these substrates 3 and 13 was
The pieces were cut into m squares, impregnated in varnishes having the compositions shown in Table 1, lifted from the varnishes, and air-dried at room temperature for 10 minutes. Next, a heat treatment was performed in an oven at 160 ° C. for 3 minutes to obtain a first prepreg sheet 1 and a second prepreg sheet 21.

[0034]

[Table 1] [Preparation of FRP molded body] The obtained first and second prepreg sheets 1 and 21 were cut into 5 cm squares, respectively, and four second prepreg sheets 2 were formed on the first prepreg sheet 1.
1 at a temperature of 170 ° C. and a pressing pressure of 20 kg / c.
The resulting product was sandwiched between aluminum foils at a pressure of m ² for 20 minutes and pressed to obtain an FRP molded body 11.

[Measurement of Coefficient of Friction] When a hard metal ball on which a weight W of 1 is applied is moved at a speed of 0.27 cm / sec using a friction coefficient measuring device (“FEM-4S” manufactured by Toyo Seiki Co., Ltd.) Was measured, and the coefficient of friction was calculated by the following equation. [Equation 1] μ = f / w

[0036]

According to the present invention, the mechanical strength is improved by impregnating the curable resin with the PTFE web as the base material, and the coefficient of friction of the surface is reduced because the PTFE web is located on the outermost layer. It is kept low. Therefore, an FRP molded product suitable for use as various sliding members and a prepreg sheet used for such a molded product can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a prepreg sheet to which an embodiment of the present invention is applied.

FIG. 2 is a cross-sectional view showing an FRP molded body to which one embodiment of the present invention is applied.

[Explanation of symbols]

 Reference Signs List 1 (first) prepreg sheet 3,23 web sheet 5,25 curable resin 11 FRP molded body 21 second prepreg sheet

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Seigo Yamamoto 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industries, Ltd. Yodogawa Works (72) Inventor Shin-ichi Chaen 1-1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin (72) Inventor Jun Asano, 1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industrial Co., Ltd. (72) Tomohisa Konishi 1-1-1, Nishiichitsuya, Settsu-shi, Osaka Daikin Industrial Co., Ltd. F-term in Yodogawa Works 4F072 AA04 AA07 AB04 AB21 AB22 AB27 AD23 AG03 AK01 AL16 4F100 AG00B AK01A AK01B AK18A AK53A AK53B DG01A DG01B DG06A DG12B DH01A DH01B GB41 JB13B J41

Claims (5)

[Claims] 1. A sheet-like web sheet made of polytetrafluoroethylene fiber, and a curable resin impregnated in the web sheet, wherein at least one surface of the web sheet is disposed. Pre-preg sheet. 2. The web sheet has a basis weight of 25 g / m ^2.
Above 250 g / m ² or less, prepreg sheet according to claim 1. 3. The fiber according to claim 1, wherein the polytetrafluoroethylene fiber has branches and / or loops.
The prepreg sheet according to 1. 4. A prepreg sheet according to claim 1, wherein the first prepreg sheet is a prepreg sheet, a sheet-like substrate made of glass woven fiber, and a curable resin impregnated in the substrate. And at least one second prepreg sheet laminated on the first prepreg sheet, wherein a part of the web sheet is disposed on a surface of the first prepreg sheet side. 5. The fiber-reinforced plastic molded product according to claim 4, wherein the second prepreg sheet is constituted by a plurality of prepreg sheets.