JPS59129235A - Production of curved surface mirror made of synthetic resin - Google Patents

Abstract

PURPOSE:To produce a curred surface mirror made of a synthetic resin, which has good shape retention, by molding a synthetic resin into the desired shape, subjecting the resulting curved surface substrate composed of the surface-cured synthetic resin to moisture conditioning, forming a metallic film on the surface thereof and then applying back coating. CONSTITUTION:For example, an acrylic resin for injection molding is injection- molded by using a mold for a convex mirror. The molding is then immersed in a silane surface-curing soln., gently pulled out of the soln., placed in a hot-air constant temp. both to cure it by crosslinking and to form a coating film, subjected to moisture conditioning, and placed in a vacuum metallizing tank where aluminum metallizing is conducted. The resulting aluminum coating film is spray-coated with a back coat paint and heated to produce a convex mirror. By subjecting the curved surface substrate to moisture conditioning prior to metallizing and back coating, deformation due to moisture absorption is greatly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a curved mirror made of synthetic resin, and more particularly, to a method of manufacturing a curved mirror made of synthetic resin with good shape stability.

Synthetic resin mirrors are used in the fields of displays, interiors, and miscellaneous goods because they are lighter than conventional ones, less susceptible to breakage, and easier to machine. Furthermore, recently, as vehicles such as automobiles become lighter, there has been a demand for practical use of synthetic resin mirrors for vehicles that are lighter and more difficult to break than conventional glass mirrors. Such mirrors made of synthetic resin are made by, for example, using a methacrylic resin template whose surface is thoroughly cleaned, a metal such as aluminum is vacuum-evaporated on the surface, and a synthetic resin is applied to protect the vacuum-deposited film. Obtained by covering with resin paint. If necessary, the substrate may be surface-hardened in advance to prevent scratches from wiping dirt such as fingerprints, dust, and mud with a cloth, making it difficult to see the mirror.

However, unlike glass mirrors that are not moisture permeable,
Conventional synthetic resin mirrors are affected mainly by the temperature and humidity of the environment in which they are used, and it is difficult to maintain a constant radius of curvature of the curved mirror, so they have not yet reached the level of practical use.

That is, as shown in FIG. 1, a hardened surface film 2 is formed on the outer surface of the mirror body j to prevent scratches on the mirror body, and a reflective film 3 made of aluminum or the like is provided on the back surface to protect it from moisture, air, and chloride. A nickel coat film 4 is provided to prevent the sialuminium from being attacked. This back coat film also covers the end portion 3' of the reflective film 3 to form a stepped film 4'. If the mirror main body is made of transparent synthetic resin such as acrylic resin, it will generally have hygroscopic properties and the side provided with the back coat film 4 will have high moisture resistance. Moisture is absorbed only from the outer surface of the membrane surface 4, and the surface expands and warps into a convex shape, changing its shape. For example, in the case of a convex mirror, the radius of curvature T shown in Figure 1 decreases significantly. There is a gap in the process of obtaining a curved mirror with ease and precision.

In view of this situation, the inventors of the present invention have developed a synthetic resin 0-
Focusing on the fact that the radius of curvature changes due to the absorption of moisture from one direction on the surface other than the back coat film, we formed a thin metal film. The curvature of the hygroscopic transparent synthetic resin mirror can be improved by molding it into a shape, avoiding heat treatment by surface hardening, and controlling the humidity of the synthetic resin base, which has a low moisture content, so that it has the same moisture content as the environment in which it will be used. The present invention was completed by discovering that the problem of radius variation can be solved.

An object of the present invention is to provide a method for manufacturing a synthetic resin mirror with good shape retention.

The present invention manufactures a curved mirror made of synthetic resin. This method of manufacturing a synthetic resin curved mirror is characterized in that a back coat film is then formed.

The synthetic resin used in this invention, acrylic),
Polycarbonate', styrene-methyl methacrylate-1
Although there are resins such as acrylonitrile-styrene copolymers, acrylonitrile-butadiene-styrene resins, etc., acrylic resins and polycarbonates are most suitable because of their high transparency and excellent other optical properties and heat resistance. For example, in the JISJ) 5705 vehicle mirror performance test, 50°C 95%R)j, 96Hr moisture resistance, 90°C
In the hot water resistance test of 11(r), the mirror substrate absorbs moisture and softens, and the radius of curvature of the convex mirror in particular fluctuates widely.
MD (i 48 ] 8.6 K9/cnl A resin with a heat distortion temperature of 90°C or higher under load is suitable, but acrylic resin with a heat distortion humidity of 100°C, a heat distortion humidity of 120°C
From this point of view, polycarbonate is preferred.

Alternatively, it can be obtained by a known method 1, such as injection molding a molded lunar phase pellet. The quality of surface accuracy, plate 157 dimensions, shape dimensions, and radius of curvature are stable, and the
Since f:i is good and is the first in terms of cost, injection D
Form I is preferred. As for the injection molding rough method, it is possible to use a general injection molding method, or to suppress the occurrence of molding distortion as much as possible.
Yield θ: In order to obtain a molded product with a high degree of curvature radius, it is desirable to use a mold temperature controller with a high density.

Preferably, the mold used for molding is corrected in advance in anticipation of variations in the radius of curvature of the curved mirror. For example, the first
As shown in the figure, the amount of change over time in the radius of curvature r of the acrylic resin convex mirror after vacuum deposition and Bafukuko-1 coating is Δr L
y) Radius of curvature R of convex mirror mold for 'a' case R = r + △r
It's a good idea to do it. The value of Δr can be determined by the amount of change in the radius of curvature over time, depending on the synthetic resin used, the molding machine, and the molding conditions.

Next, the mirror substrate may not be subjected to surface hardening treatment, or a known hardening treatment agent such as silicone type, multi-capacity acrylic type, urethane type, or acrylic-urethane type can be used as the second hardening agent. However, silicone-based and polyacrylic-based materials are preferred because of their excellent scratch resistance.

The composition can be applied to the surface of the mirror substrate by a known method such as spray coating, casting coating, brush coating, or dipping coating. If the surface of the mirror base 4J is cleaned by degreasing with an organic solvent or ultrasonic cleaning before painting, it is possible to obtain a mirror with a good appearance without any blemishes.

For drying, a thermosetting method is generally used, and when the temperature is 60 to 130°C, it takes 30 to 120 minutes in a VC. The roughness of this coated mulberry paste is 1 to 30 microns, and cracks are more likely to occur if it is finer.

Humidity control fd in the present invention is relative humidity 50-95%, more convenient (d60-80 candy, temperature is 1
20°C to 50°C is more convenient than 0°C to 80°C. At humidity levels below 50%, the effect is small due to large fluctuations in the radius of curvature; at humidity levels above 95%, condensation occurs on the cured substrate, and dry deposition results in a beautiful exterior (f
” 1 cannot be obtained. [warm counterfeit] (below 1"C, the variation of d curvature radius is large and there is no effect, 8 (]"C
This is not preferable because the substrate is deformed.

Metal thin 11+',! Sha is performed using the direct-ku koi-gi method, ion brating method, subakling method, etc. For example, after coating the surface with a hardening film, place the aluminum-moistened substrate in a vacuum deposition tank for 10~]
At OTorr vacuum level, aluminum can be heated to 100A to 50A.
Deposit to a thickness of 0A. Pretreatment is not particularly necessary, but it is preferable to do so, as dust may adhere to the reflective film or a rough surface like an orange film may appear on the reflective film, making it impossible to obtain a high-quality mirror.

A curable resin film is coated on the surface of the metal thin film, and it is made convenient by irradiating it with active energy sources such as ultraviolet rays, electron beams, or heat. The coating may be applied by brush coating, spray coating, curler/flow coating, etc., but is preferably applied to a film thickness of 10 to 50 μm.

An embodiment of the present invention will be described with reference to the drawings. Acrylic resin for injection molding (Kyowa Gas Chemical T-Gyo Co., Ltd. Barabeno l-HR)
was injection molded using a 3-inch convex mirror mold with a radius of curvature of 1300 mm. Next, the molding machine was immersed in a 7-run surface hardening solution, gently pulled up, placed in a hot air constant temperature bath at 85°C for 120 minutes to crosslink and harden, and after forming a coating film with a thickness of 10 μm,
Humidity was controlled for 40 hours at 80% RH. Next, the aluminum was deposited in a vacuum deposition tank at a vacuum level of 5 x ] 0'-5 Torr to form a film with a noisiness of about 0.02μ, and then a back coat paint was spray-painted on the aluminum thin film. , 75"C127 Heated for 1 hour to a thickness of about 30μ
A convex mirror was obtained. FIG. 2 shows the change over time in the variation 5 (lz r) of the radius of curvature of the convex mirror made by the above procedure. The equilibrium value of Example 1 is 150, but
When the humidity adjustment process is omitted from the above-mentioned +111J, the average N value is 300 mm, and the variation of the radius of curvature (Δr) is approximately 1/2 that due to the humidity adjustment.

Surface hardening, humidity control, and vacuum deposition as described above.
A curved mirror with good shape and dimension retention can be obtained by this method, and this point will be explained below along with the manufacturing method.

Table 1 d is a detailed explanatory diagram of the present invention. Shape] (5) ↓ ↓
↓ ↓ [Molding:] (A) (Tone
Moisture:] (C) [Surface hardening] (B) (Surface hardening)
(B) ↓ ↓ ↓ ↓
[Surface hardening:] (B) [:Table m] Curing] (B) [Vacuum deposition] ■) [Humidity adjustment] (C) ↓ ↓
↓ ↓ [Vacuum deposition] 0 [Vacuum deposition:
] (1)) C protective film coating] (g) [Vacuum deposition] (to) ↓ ↓ ↓ ↓ ■ The manufacturing process is dehumidified by molding and surface hardening treatment, and has good shape and dimension retention even when humidity is adjusted. A curved mirror cannot be obtained. 1■
In the manufacturing process, the moisture content of the substrate increases due to humidity conditioning, and during the subsequent surface hardening treatment, cracks occur due to the solvent in the curing liquid.
A curved mirror with a good appearance cannot be obtained. In the manufacturing process No. 11, the radius of curvature fluctuates greatly due to the unilateral absorption of moisture from surfaces other than the reflective film surface I of the curved mirror, making it impossible to obtain a precise curved mirror. According to the manufacturing step 1 of the method of the present invention, a curved mirror with good shape and dimension retention can be obtained.

Figure 3 d1 shows that a good convex mirror was obtained in which the amount of change over time in the radius of curvature △r of the convex mirror made of a rubber-based soft protective film in the present invention was less than 〈〉〉〉〉0〉. This shows that a mirror with good shape and dimensions was obtained from the convex ■■ mirror made of a hard protective film. The soft protective film d in the present invention is formed from a rubber-based protective paint, and examples of such paint include those containing polybutadieno-based, polyisopreno-based, or soft vinyl chloride-based soft resins.

Table 2 shows the polycarboy-1 screen mirror according to the present invention, and the curve r of the radius of curvature over time is 100111.
11, indicating that a good external mirror can be produced.

In this example, a 7n thickening treatment was carried out using a brimer coating for polycarbonate 1 and an Organo 70 hardening solution for polycarbonate.

Table 2 Parabets 1. HR100°C150 Panlite L-1250Y 140°C 1
00 The present invention has the structure as explained above, and in particular, a curved mirror base made of a transparent synthetic resin material such as Ac1 Nor resin which is molded into a desired shape and hardened in Table 1f11 is coated with a thin metal film by vapor deposition. Since it has a humidity control structure of i￥iJ, the shape change of absorption i8 VC, 1 is significantly reduced.
As a result, a synthetic resin curved mirror with scratch resistance and optical box resistance comparable to that of a single-sided mirror made of inorganic glass, and also has a light weight and is difficult to break. - Advantages of easy legal control and efficient manufacturing.

In addition, the curved eel of this invention is

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a convex mirror made of synthetic resin, and FIGS. 2, 3, and 3 are curvature change curves over time showing the effects of the present invention, respectively. Patent applicant: Kyowa Gas Chemical Industry Co., Ltd.] Figure 0 2 4. 6 8 10 1.2 14
16 Number of days left unused (△r) Fig. 2 Change in the radius of curvature of a convex mirror over time Bk (her) vs. effect of humidity control Number of days left unused (1 item per room) Fig. 3 Change over time fit (△ 7) Effects of Soft Protective Film on (Voluntary) Procedural Amendment May 25, 1980 (2) Name of Patent Application No. 4776 of 1982 Case of a person who manufactures a synthetic resin curved mirror for one day Relationship with Patent applicant address: 3-8-2-4 Nihonbashi, Chuo-ku, Tokyo Sodej
1 5. Supplement 1 Column 6 of “Description 4-1 Detailed Description of the Invention” Contents of amendment (1) Page 2 of the specification, line 12 “Mekcryl Resin J (/
Delete "sex type" following fC. (2) In the 7th line of page 5 of the specification, the phrase ``radius of curvature'' should be changed to ``
"of the radius of curvature" is corrected. (3) 1 multi-capacity on page 6, line 13 and line 16 of the specification]
Correct it to read ``multi'1.-j ability''. (4) On page 1, line 2J of the specification, the word "Karlan" is corrected to "curtain." (5) In the 8th shell, line 16, the word [former] is changed to “
Corrected to ``molded products''. (6) In the line following Table 2 on page 12 of the specification, the word ``like'' is corrected to ``like''. (7) The description from page 13, line 3 onwards of the specification is corrected as follows. ``Figure 2 shows the effect of humidity control on the change over time in the radius of curvature of a convex mirror, and Figure 3 shows the effect of qψ (quality preservation film) on the change over time in the radius of curvature of a convex mirror. Amendment (Method) 1. Indication of the case Patent Application No. 1982-1776 2. Name of the invention Method for manufacturing a synthetic resin curved mirror 3. Person who makes correction 4-ili Seimei Zen Order 1988 4 Monday 6th Sho I 1” Shipped April 20, 1958 0246 810121416 Note 5 + a'4'y (G) Figure 2 Hyoukan e for a while) Figure 3

Claims (1)

[Scope of Claims] A method for manufacturing a synthetic resin curved mirror, in which a thin metal film is formed on the surface of a curved substrate after conditioning the humidity of the plane substrate, and then a back coat film is formed to make the mirror 7 to 4″f. 2. Synthetic resin is acrylic resin or polycarboy, -
The manufacturing capacity method according to claim 1, which is 3) The manufacturing force method according to claim 1, wherein the radius of curvature of the mold used for molding is corrected in advance in anticipation of fluctuations in the half-curvature of the curved mirror. 4) The manufacturing method according to claim 1, wherein the back coat film is a soft synthetic resin.