JPH0668594B2 - Carbon fiber reinforced thermosetting resin camera shutter blades - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a camera made of carbon fiber reinforced thermosetting resin (hereinafter abbreviated as CFRP) which is excellent in specific strength and specific rigidity, and is excellent in flatness and light shielding property. Shutter blades for a vehicle.

[Conventional technology and problems]

Since CFRP has excellent characteristics such as high specific strength, specific elastic modulus, fatigue resistance, and damping vibration, CFRP has been used in the fields of space / aviation, automobiles, sports, leisure, and the like.

However, most of the CFRP forms conventionally used have a thickness of about 0.15 mm or more. 0.15 mm
If an ultra-thin plate made of CFRP with the following thickness, which does not warp, has excellent flatness and light-shielding properties, and is unlikely to crack is obtained, it will be a very useful material for camera shutter blades. It is possible to manufacture high-performance shutters that cannot be obtained with. Recently, there have been reports of using CFRP for shutter blades of cameras, but these unidirectional reinforcing plates of carbon fiber are used alone or in the form of being bonded to a metal foil.

However, although the unidirectional strengthened plate certainly has excellent strength and elastic modulus in the fiber orientation direction, it is significantly weakened in the perpendicular direction, and the CFRP thin plate is apt to crack.

Further, when laminated with a metal foil, the strength in the direction perpendicular to the fiber is improved, but the merit of reducing the weight by using CFRP is reduced.

Further, it is extremely difficult for a camera shutter blade composed of only a thermosetting resin and carbon fiber to obtain a perfect light shielding property due to the thinness of the blade.

[Object, Structure and Effect of Invention]

The present inventors have arrived at the present invention as a result of their studies to provide a shutter blade for a camera made of CFRP that does not have the above-mentioned problems. The present invention relates to synthetic resin
Unidirectionally oriented thermosetting resin prepreg sheets containing 0.5 to 15% by weight of carbon black and having a carbon fiber areal weight of 7 to 150 g / m ² Three or more layers are symmetrically cross-laminated with respect to the neutral plane in the thickness direction. A shutter blade for a camera made of an ultrathin carbon fiber reinforced thermosetting resin having a total thickness of 20 to 150 μm, which is formed by curing.

The CFRP camera shutter blade of the present invention is less likely to be cracked, does not warp, and has excellent light-shielding properties and abrasion resistance. This product uses a thermosetting resin containing 0.5 to 15% by weight of carbon black with respect to the resin as a base material and has a small carbon fiber areal weight and a plurality of unidirectionally oriented prepreg sheets are laminated symmetrically and heated and heated. By pressure-hardening, a CFRP ultrathin plate having a small difference in strength in the vertical and horizontal directions and hard to crack can be obtained.

Moreover, since the orientation of the carbon fibers is plane-symmetrical such as 0 ° / 90 ° / 0 °, the molded plate has no warp,
Further, since the base material thermosetting resin contains carbon black, the fine particles fill the minute gaps generated between the carbon fiber single fibers and improve the light-shielding property, which is an essential condition for camera shutter blades. .

In addition, carbon black used for the purpose of improving the light-shielding property acts as a flow regulator when heat-curing a thermosetting resin, and carbon fibers accompanying an excessive resin flow due to a decrease in resin viscosity during heating and pressurization. A CFRP ultrathin plate having extremely excellent flatness can be obtained without causing disorder of orientation.

In addition, since the carbon black is uniformly dispersed in the thermosetting resin, the outermost surface layer of the heat-cured CFRP ultrathin plate becomes a resin layer containing carbon black, and the abrasion characteristics desired as a shutter blade are also improved. .

The CFRP ultrathin plate thus obtained is punched into a predetermined shape and size to obtain a camera shutter blade. The carbon fibers used here are classified into polyacrylonitrile-based, rayon-based, pitch-based, etc. depending on the type of raw material precursor, but there is no particular limitation and commonly used fibers are applied. An epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a phenol resin, a polyimide resin or the like can be used as the base material thermosetting resin.

The amount of carbon black mixed and used in the thermosetting resin is 0.5 to 15% by weight based on the thermosetting resin. If it is less than 0.5% by weight, the light-shielding effect is not sufficiently exhibited. On the other hand, if it exceeds 15% by weight, the opening of the carbon fiber in the prepreg stage is hindered, and the fluidity of the resin at the time of molding becomes too small, and the good light-shielding property and flatness deteriorate, and a good CFRP ultra-thin plate is obtained As a result, the shutter blade is not satisfactory.

The CFRP camera shutter blade of the present invention has a total thickness of 20 to 150 μm. When the total thickness is more than 150 μm, the mechanical characteristics are improved but the weight is increased, and the high-speed mobility of the shutter blade is improved. It is not preferable because it decreases. Also,
If it is less than 20 μm, the light-shielding property becomes poor. The average particle size of carbon black can be 0.1 μm or less, but in the present invention, the average particle size is preferably 0.05 μm or less. The shutter blade for a camera of the present invention is 20
It is an ultra-thin plate of CFRP having a thickness of up to 150 μm, and the flatness and light-shielding property of this shutter blade are greatly affected by the openability and the opening of the existing carbon fiber bundle. Therefore, if the average particle diameter of the carbon black mixed and used in the thermosetting resin is 0.1 μm or more, it prevents the opening of the carbon fiber and reduces the flatness and the light-shielding property. In the CFRP ultrathin plate of the present invention, three or more layers of prepreg are symmetrically cross-laminated with respect to the neutral plane in the thickness direction, and therefore carbon fiber and carbon black are added in heating and pressure molding as compared with unidirectional orientation lamination. There is a tendency that the flow of the thermosetting resin contained therein decreases. Therefore, fine air bubbles present in the prepreg, there is a concern that openings and the like reduce the light-shielding property, but in order to eliminate this concern, the openings of the prepreg do not occur between the bundles of carbon fibers or filaments, and It is particularly preferable to use carbon black having an average particle diameter of 0.05 μm or less for the purpose of providing appropriate fluidity and further ensuring the light-shielding property of the ultrathin plate that has been heated and pressure-molded. The prepreg is made by impregnating a unidirectionally oriented carbon fiber bundle with a thermosetting resin in which a predetermined amount of carbon black is added and sufficiently mixed.

The prepreg used in the present invention has a carbon fiber basis weight of 7 to 150 g.
/ M ² is required. If the basis weight is less than 7 g / m ² , the prepreg is opened and a good molded product cannot be obtained. Also, 150g
With a prepreg having a basis weight of more than / m ² , the thickness of the molded product becomes too large and the object of the present invention cannot be achieved. The prepregs are laminated so as to have plane symmetry such as 0 ° / 90 ° / 0 °. The CFRP ultra-thin plate formed by heating and pressing this has balanced strength and elastic modulus in each direction,
No warpage occurs. The shutter blade punched from this ultra-thin plate into a predetermined size and shape has no cracks and has a good light-shielding property. If the prepreg layers are not plane-symmetrical, warpage occurs and a preferable molded product cannot be obtained.

(Examples and Comparative Examples) Example 1 A unidirectionally oriented carbon fiber was impregnated with 5% by weight of carbon black having an average particle diameter of 0.03 μm and sufficiently mixed to obtain an epoxy resin-based base material, and the basis weight of the carbon fiber was 27 g / m ^2. I made a prepreg sheet. This prepreg sheet 3 ply is laminated in 0 ° / 90 ° / 0 ° so as to be plane-symmetrical and set in a mold, and then a mold in which the prepreg laminate is sandwiched is set in a hot press preheated to 130 ° C., Apply a pressure of 5 kg / cm ² 9
Cured in 0 minutes.

Then, it was gradually cooled to room temperature to obtain an ultrathin CFRP plate. This molded product was a very excellent CFRP ultrathin plate with a thickness of 96 μm, small thickness unevenness, no disorder in the orientation of the carbon fibers on the side of the molded plate, and no warpage. From this CFRP ultrathin plate, shutter blades for a camera were punched into a predetermined size and shape. The obtained shutter blade was excellent in flatness without cracking, and had no pinholes which would cause deterioration of the light-shielding property. By the way, the obtained C
As a result of the tensile test of the FRP ultra-thin plate using the Instron tester, the tensile strength is 130k in the surface layer fiber orientation direction.
It was g / mm ² and 63 kg / mm ² in the perpendicular direction.

Example 2 In the same manner as in Example 1, 2% by weight of carbon black having an average particle diameter of 0.015 μm was added, and the epoxy resin base material sufficiently mixed was impregnated into the unidirectionally oriented carbon fiber to give a carbon fiber basis weight.
A prepreg sheet of 27 g / m ² was obtained.

This prepreg sheet 4 ply is 0 ° / 90 ° / 90 ° / 0
Then, a CFRP ultrathin plate was obtained by laminating at the same temperature as in Example 1. The total thickness of the obtained molded plate was 123 μm, which was good without warpage. A shutter blade for a camera was punched out from this molded plate, but it was a good shutter blade without cracks and pinholes.

Example 3 In the same manner as in Example 1, 7% by weight of carbon black having an average particle diameter of 0.015 μm was added, and the epoxy resin base material sufficiently mixed was impregnated into the unidirectionally oriented carbon fiber to give a carbon fiber basis weight.
Prepreg sheets of 10 g / m ² and 19 g / m ² were obtained. Here, 1 ply of prepreg with a basis weight of 19 g / m ² is used as the center layer, and 1 ply of each prepreg with a basis weight of 10 g / m ² is laminated on both sides so that the orientation of the carbon fibers is 0 ° / 90 ° / 0 °. did. This laminated sheet is cured in the same manner as in Example 1 to obtain CFR.
A P thin plate was obtained.

The obtained molded plate had a total thickness of 43 μm and was good without warpage. A shutter blade for a camera was punched out from this molded plate, but it was a good shutter blade with no cracks and no pinholes.

Comparative Example 1 In Example 1, a CFRP ultrathin plate was molded under the same conditions except that carbon black was not added.

In the obtained molded plate, the orientation of the carbon fibers on the side was disturbed.
Further, the punched shutter blade was twisted due to the disorder of the fiber orientation. There were also pinholes.

[Brief description of drawings]

FIG. 1 is a perspective view showing the structure of a shutter blade for a camera of the present invention, FIG. 2 is a perspective view in which the structure of the shutter blade in FIG. 1 is changed, and FIG. 3 is a change in the structure of the shutter blade in FIG. It is the figure which showed as a model. 1: CFRP central layer, 2: CFRP surface layer symmetrical to each other with respect to the central layer, 3: CFR symmetrical to each other with respect to the central layer
P middle layer a: carbon fiber, b: carbon black, c: thermosetting resin

Claims (2)

[Claims] 1. One or more unidirectionally oriented thermosetting resin prepreg sheets containing 0.5 to 15% by weight of carbon black based on synthetic resin and having a carbon fiber basis weight of 7 to 150 g / m ^{2 in} the thickness direction. Shutter blades for camera made of ultra-thin carbon fiber reinforced thermosetting resin with a total thickness of 20 to 150 μm, which are formed by symmetrically cross-laminating and hardening with respect to the vertical surface. 2. A shutter blade for a camera made of carbon fiber reinforced thermosetting resin according to claim 1, which is carbon black having an average particle diameter of 0.05 μm or less.