JPS6127504A - Production of carbon fiber reinforced plastic mirror - Google Patents

Abstract

PURPOSE:To produce a carbon fiber reinforced plastic (CFRP) mirror having less waving of the specular surface by adhering a metallic surface deposited by evaporation on a polished surface and a carbon fiber reinforced plastic laminate of which the surface skin part is made of a non-woven fabric or assembled mica sheet then parting the polished surface and the metallic surface deposited by evaporation. CONSTITUTION:The inside of the CFRP laminate is made of, for example, bidirectionally woven cloths 12 as the base material and the surface skin layer part 11 is made of the layer consisting of a non-woven fabric or assembled mica sheet as the base material. The metallic surface deposited by evaporation on the polished surface and the surface skin part 11 of the CFRP laminate are adhered by means of a solventless type adhesive agent and thereafter the polished surface and the metallic surface deposited by evaporation are parted to transfer the specular surface to the CFRP laminate, by which the mirror is produced.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a collimator mirror for a large space chamber;
The present invention relates to a method of manufacturing a carbon fiber reinforced plastic (CFRP) mirror suitable for a condensing mirror of an artificial satellite.

(Prior Art) Parabolic mirrors that collect parallel light and collimator mirrors that convert focused light into parallel light are used in the space environment or in a laboratory (space chamber) that simulates the space environment on the ground. Flat mirrors and convex mirrors are also used to widen the field of view of television cameras. In the space environment, there is a large temperature difference between day and night, and the mirror has a temperature of 10
The temperature reaches close to 0°C and drops to around -60°C in the dark (night).

The material of the mirror is generally a light metal (eg, aluminum alloy) or fiber-reinforced plastic (FRP), but in either case, the mirror surface of the mirror is formed by vapor-depositing metal (eg, aluminum). The most suitable material for the mirror is CFRP, which is light, has high rigidity, and has little dimensional change due to temperature changes.

However, the problem is how to form a metal vapor deposited baking surface on a CFRP plate. In order to fully demonstrate its function as a mirror,
First of all, it is necessary that the precision of the shape, such as a plane, a spherical surface, a parabolic surface, etc., is high. Next, it is necessary that the surface has small irregularities (roughness) and high reflectance. These surface irregularities include microscopic surface roughness and relatively thick ridges, which are the subject of the present invention. Microscopic surface ridges cause problems because they reduce the reflectance of the surface and disturb the direction of reflection.

FIG. 2 is a schematic cross-sectional view of the vicinity of the skin of a conventional CFRP laminate. CFRP laminates are generally made by laminating two-way woven carbon fiber cloths 12 and impregnating them with a thermosetting resin composition (eg, an epoxy resin composition). In the figure, 1 is the warp yarn that constitutes the carbon fiber cloth 12, 2 is the weft yarn, and 3 is the impregnated resin. Generally, such CFR
For 'P laminated products, first layer carbon fiber cloth.

It is produced by impregnating a resin composition under reduced pressure and then heating and curing the impregnated resin. The curing temperature is generally 120-160°C. However, when the temperature is reduced to room temperature after curing and molding, four portions 4 and convex portions 5 are formed on one surface as shown in FIG. Here, the position of the convex portion 5 is the middle where the warp yarn 1 and the weft yarn 2 overlap, and the concave portion 4 is located elsewhere. This is caused by thermal contraction of the resin.
At the position where the warp and weft threads overlap, the resin content is low, so the heat shrinkage is small, but in other parts, the resin content is relatively high, so the heat shrinkage is large and causes dents.

Even if metal is vapor-deposited on the surface of such a CFRP laminate product with large undulations to form a mirror surface.

A mirror surface with sufficient reflection directionality cannot be obtained. Therefore, the third
As shown in a schematic cross-sectional view in the figure, it is conceivable to scrape the surface of the CFRP laminate shown in FIG. 2, remove the ridges, and then apply a coating resin layer 6t on the surface. The purpose of coating here is that carbon fibers (about 7 μm in diameter) are exposed on the surface of the CFRP laminate, which is simply shaved.
This is because even if it is deposited on this surface, a mirror surface with high reflectance cannot be formed due to the latitude of the surface.

FIG. 4 is an enlarged view of section A in FIG. 3. C with shaved surface
On the surface of the FRP laminate, there are partially exposed carbon fibers 7a, loose carbon fibers 7b,
y) There is a hole 8 where the carbon fiber is missing, and there is an unevenness of several μm corresponding to the diameter of the carbon fiber. - To obtain a glossy mirror surface on the surface, K must be 0.1 μm or less for the thorny surface.

This is not enough. Therefore, a coating resin 6 is applied to reduce the surface roughness, but as shown in FIG. 4, this is impossible because the exposed portions of the carbon fibers are wetted by the resin.

What can be considered here is K as shown in Figure 5.

First, a glass plate (or gold plate) 9, which has an extremely small surface roughness, is coated with a metal 13 gold that is smooth and vapor-deposited to give it a mirror surface. At this time, it is best to apply a small amount of mold release agent (silicone type, fluorine thread, etc.) to make it easier to peel off the deposited layer. The CFRP laminate, excluding the surface ridges (for example, lightly sanded), is then glued with adhesive 10. Next, when the glass plate 9 and the CFRP laminate are released from the mold, the metal vapor deposited layer is transferred to the CFRP laminate by the adhesive, and the CFRP 9 has a mirror surface with small surface roughness.
It can be a mirror.

By the way, the adhesive 10 is made so as not to leave any air bubbles inside.
A solvent-free thermosetting resin composition (for example, an epoxy resin composition) is used. In this structure, the curing temperature of the resin (
At temperatures above room temperature, a mirror surface with no undulations can be obtained, but at low temperatures (approximately -60°C) encountered in the space environment, it has been found that ridges appear. FIG. 6 is a schematic cross-sectional view of the vicinity of the skin of a CFRP laminate to which the metal vapor deposited layer 13 was transferred by the above method, and the adhesive was cured at room temperature before transfer.

Shows the state cooled to a low temperature. Here, the basic CFf'
When the temperature of the LP laminate becomes low, convex portions 5 and concave portions 6 are formed, ridges appear, and the metal vapor deposited layer 13K on the surface of 9 is formed.
When ridges appear on the mirror surface, it becomes K.

(Object of the invention) The present invention involves depositing metal on a polished surface, applying a solvent-free adhesive to the deposited surface, bonding a CFRP laminate, and then separating the polished surface and the metal deposited surface. It is an object of the present invention to provide a method for mirroring CFRPS mirrors with small ridges on the mirror surface when manufacturing a CFRP mirror by molding and transferring a mirror surface onto a CFRP laminate.

(Structure of the Invention) The present invention involves depositing metal on a polished surface, applying a solvent-free adhesive to the deposited surface, bonding a CFRP laminate, and then separating the polished surface and the metal deposited surface. A method for manufacturing a CFRP mirror in which a mirror surface is transferred to a CFRP laminate by molding, in which the skin on the metal-deposited side of the CFRP laminate is a layer based on a nonwoven fabric or a laminated mica sheet. .

FIG. 1 is a schematic cross-sectional view of the vicinity of the skin part of a CFRP laminate according to an embodiment used in the present invention. The inside of the CFRP laminate may be made of two-way woven cloth 12 as a base material;
1 is a layer based on a nonwoven fabric or a laminated mica sheet as described above, and this layer alleviates the waviness.

As the nonwoven fabric, known materials such as polyester nonwoven fabric and carbon mat are used.

As a laminated mica sheet, 9, for example, a diameter of 0.3 to 1.0
A sheet having a thickness of about 0.08 to 0.15 μm is used by dispersing mica particles with a thickness of about 2 to 4 μm in water and making a sheet of the same. Usually, it is used as an insulating base material for stator coils of large rotating electric machines, impregnated with epoxy resin.

The manufacturing method of the present invention is applicable to any type of mirror having a flat, concave, or convex mirror surface.

As the material for the polished surface of the present invention, glass or polished metals such as chromium and titanium are used. There are no particular restrictions on the polishing method, but it is preferable that the polishing be as precise as possible.

Metal is vapor-deposited on the polished surface, but there are no restrictions on the vapor deposition method (1), etc., and the vapor deposition is carried out using a known method (9 conditions, etc.).

In the present invention, a solvent-free adhesive is used to prevent the generation of bubbles, examples of which include epoxy resin adhesives and unsaturated polyester adhesives.

CFRP laminated products are made by laminating carbon fiber base materials such as carbon cloth, and gold W! A thermosetting resin composition such as an epoxy resin composition is impregnated with a thermosetting resin composition such as an epoxy resin composition under reduced pressure and then heated and cured after being placed in a container, or a thermosetting resin composition such as an epoxy resin composition is applied to a carbon fiber base material such as carbon cloth in advance. It is made by laminating prepreg sheets impregnated with materials and made into a semi-cured state.

Those that are hot press molded in a mold are used.

In the present invention, the skin portion on the metal-deposited side of the CFRP laminate is a layer based on a nonwoven fabric or a laminated mica sheet.

An example of the manufacturing method of the present invention will be explained.

Metal is deposited on a precisely polished mold to create a mirror surface.

The mirror surface of the CFRP mirror is the vapor-deposited surface that is in contact with the mold. The thickness of the vapor-deposited surface may exceed 1 μm. Furthermore, since the shape accuracy of the mirror surface, surface roughness, and surface of the mold are copied, it is preferable that the mold be made by polishing glass, but it may also be made of metal. In order to make the metal-deposited surface easier to peel off from the mold, it is desirable to apply a thin layer of mold release agent (eg, silicone-based, fluorine thread) to the convex mold before metal is deposited.

Next, an adhesive is applied to the mirror surface, a CFRP laminate with a unidirectionally woven carbon cloth as the upper skin is placed thereon, and the adhesive is cured. After that, when the KCFRP laminate is released from the mold, the mirror surface is transferred to the CFRP laminate, and the CFRP
You get a mirror.

If air bubbles form inside the adhesive, bubbles will appear on the mirror surface, so a solvent-free adhesive is used. Also C
The surface roughness of the FRP concave surface can be processed to +tt because the adhesive can be absorbed into the depression.In fact, to improve the adhesion with the adhesive, sandpaper (for example, 600
) It's better to be lazy. Furthermore, the shape accuracy of the CFRP concave surface.

Since irregularities in the shape of the precision convex mold can be covered by the thickness of the adhesive, some errors are allowed.

The metal deposited to form the mirror surface is preferably aluminum, which has the highest reflectance, but may also be chromium, nickel, silver, or the like.

In both cases, the vapor-deposited surface facing the precision convex shape is densely formed, and the surface unevenness is extremely small after transfer. Adhere in reverse °
The other side should be porous and have an uneven surface so that it will adhere better to the adhesive. Such a deposition surface can be formed by depositing aluminum, for example, at a high speed (approximately 20 to 100X/sec) and thickly (
(approximately 1 to 3 μm) can be obtained by vapor deposition.

In the present invention, it is desirable that the solvent-free adhesive applied to the metal-deposited surface be cured at around room temperature. Further, it is preferable to fill the adhesive with inorganic powder having a small particle size (for example, titanium oxide, iron oxide monoquartz, alumina) to reduce the coefficient of thermal expansion of the cured product. The inorganic powder preferably has an average diameter of 0.5 mμ or less from the viewpoint of mirror reflectance.

In the manufacturing method of the present invention, if the shape accuracy of the CFRP surface is poor with respect to the polished surface, the adhesive becomes thick in 9 parts. In this case, instead of using an adhesive alone, a woven or non-woven fabric made of inorganic fibers (e.g. glass fiber) or organic fibers (e.g. polyester) or a laminated mica sheet made of fine mica particles is impregnated and inserted. Good too.

In particular, when a laminated mica sheet is used here, the mica particles act to weaken the influence of the weave of the carbon cloth of the CFRP, and the waviness of the mirror surface is reduced.

(Effects of the Invention) According to the present invention, a mirror with small ridges on the mirror surface and good reflection directionality can be obtained over a wide temperature range.

(Example) The present invention will be described in detail. Parts are by weight.

The method of transferring the metal vapor deposited layer was the same for both Examples and Comparative Examples. That is, the thickness is 6 mm (the size is approximately 20 cm)
A silicone mold release agent (QZ-13, manufactured by Chipa Co., Ltd.) was applied to the surface of a (m square) glass plate, and wiped off with a cloth until traces of scratches were no longer visible. The metal vapor deposition layer that will become the mirror surface is made of pure aluminum in a vacuum of 1.5 x 10-' Torr.
It was deposited to a thickness of 20 μm at room temperature. The deposition rate was approximately 201/sec up to a thickness of 0.5 μm, and the deposition rate was approximately 80×/sec thereafter.

As an adhesive, a room temperature curable epoxy resin composition (manufactured by Shell Co., Ltd., bisphenol type epoxy resin EP-815,1
00 parts and 50 parts of modified diaminodiphenylmethane EH-551 manufactured by Mudenka Co., Ltd.) was used. Preheat the glass plate and CFRP laminate to 50°C, apply adhesive on the metal vapor deposited layer of the glass plate, place the CFRP laminate (about 15 cm square), and place 90 layers of paper on top of 5. After placing the adhesive on it and extruding the excess, it was cured at 30° C. for 12 hours. Here, preheating to 50℃ is to
This is to lower the viscosity of the adhesive and make it easier to spread. After that, when the glass plate and the CFRP laminate are released from the mold, the metal vapor deposition layer is transferred to the surface of the CFRP laminate using the adhesive.
The result is a glossy mirror surface with high reflectivity.

The ridges on this mirror surface were measured using a stylus-type surface roughness measuring device (Tokyo Seimitsu, SURFCOM). All surfaces of the CFRP laminates were polished with 600-grit sandpaper until the undulations created during molding disappeared, and then bonded.

(Comparative example) The CFRP laminate product of the comparative example is made of plain-woven carbon cloth (manufactured by Toshisha Co., Ltd., Torekana 6343) at a density of 4.5 sheets/round.
Laminated to a thickness of 0 mm, alicyclic epoxy resin composition (UCC
Alicyclic epoxy resin ERL4221.100 parts manufactured by
90 parts of hexahydro-7-talic anhydride and 1 part of benzyldimethylamine) were mixed at 70°C and 0.01 To
After impregnating under reduced pressure under RR, it was cured at 120°C for 3 hours and then at 160°C for 5 hours under atmospheric pressure.

The mirror surface ridges transferred to the CFRP laminate of the comparative example are -
When measured at 60° C., the unevenness was approximately 0.75 μm.

(Example) A CFRP laminate was molded using the same materials and under the same conditions as in the comparative example, except that the skin layer shown below was used.

In Example 1, a polyester nonwoven fabric (Nippon Vilene, H8007) was used as the base material for the skin layer 11 shown in FIG. An epidermal layer with a thickness of 0.10 m+ was created.

In Example 2, the 9th skin layer was carbon mat (Toshiba).
Trading card mat BO-030) as a base material.

An epidermal layer with a thickness of 0.15 mm was formed.

In Example 3, a soft unfired laminated squid sheet (average diameter: 0.4 mm, average thickness: 3 μm) was produced by paper-making without using a binder, as the 9 skin layers.
．． A skin layer with a thickness of 0.10 mm was formed using a sheet with a thickness of 10 mm and an average density of 1.5 g/cm3 as a base material.

When the mirror surface ridges transferred to the CFRP laminate of each example were measured at -60°C, the unevenness was 0 in Example 1.
．． 50 μm, and 0.35 μm in Example 2.

Further, in Example 3, it was reduced to 0.25 μm.

[Brief explanation of drawings]

Figure 1 is a schematic cross-sectional view of the vicinity of the skin of an example of the CFRP laminate used in the present invention, Figure 2 is a schematic cross-section of the vicinity of the skin of a conventional CFRP laminate, and Figure 3 is a resin coating on the surface. A schematic diagram of the skin area of a layered CFR, P laminate; Figure 4 is an enlarged view of part A in Figure 3; Figure 5 is a schematic diagram of a 90FRP laminate with a metal vapor deposited layer transferred to the surface; FIG. 6 is a schematic cross-sectional view of the vicinity of the skin portion of the mirror obtained therefrom. Explanation of symbols 1... Warp thread 2... Weft thread 3... Impregnated resin 4... Concave portion 5... Convex portion 6... Coating resin layer 7.7a, 7b... Carbon fiber 8...・Carbon fiber missing hole 9...Glass plate 10...Adhesive 11...
Outer skin part 12... Bidirectional woven cloth 13...
Vapor deposited metal Figure 1 Figure 2 (211 $30 4th Required △ Procedural amendment (voluntary) October 1981 38 1. Indication of the incident 1982 Patent Application No. 148248 2. Name of the invention Carbon fiber reinforced plastic mirror Manufacturing method 3, relationship with the case of the person making the amendment Name of patent applicant: +445) Hitachi Chemical Co., Ltd. 4, Agent
Person 5, after vapor-depositing the metal to be corrected, applying a solvent-free adhesive to the vapor-deposited surface, and gluing the CPRP laminate,
"After bonding the metal surface deposited on the polished surface and the CFRP laminate with a solvent-free adhesive," I am corrected. 3) On page 10, between lines 4 and 5, add K "In some cases, adhesives may be applied to CFRP laminates." In the method for manufacturing a carbon fiber reinforced plastic mirror, the carbon fiber reinforced plastic laminate product K111 surface is transferred by releasing the polished surface and the metal vapor deposited surface after the attached patent claims have been applied. 1. A method for manufacturing a carbon fiber reinforced plastic mirror, characterized in that the skin on the metal vapor deposited side of the product is a layer based on a nonwoven fabric or a laminated mica sheet.

Claims (1)

[Claims] 1. Deposit metal on the polished surface, apply a solvent-free adhesive to the deposited surface, adhere the carbon fiber reinforced plastic laminate, and then release the mold between the polished surface and the metal deposited surface. In a method for manufacturing a carbon fiber reinforced plastic mirror in which a mirror surface is transferred to a carbon fiber reinforced plastic laminate, the skin portion on the metal vapor deposited side of the carbon fiber reinforced plastic laminate is a layer based on a nonwoven fabric or a laminated mica sheet. A method for manufacturing a carbon fiber-reinforced plastic mirror.