JPH0375006A - Improved mirror - Google Patents

Abstract

PURPOSE:To improve the corrosion resistance, durability and workability by applying coating material taking a specified amino modified epoxy resin as a binder onto a metallic protective film of a silver mirror surface, and hardening the same to form a back coating film. CONSTITUTION:An improved mirror comprises a glass base plate 1, a silver mirror surface film 2 formed on the glass base plate, a metallic protective film 3 formed on the silver mirror surface in order to improve the chemical durability of the silver mirror surface film 2 and a back coating film 4 formed on the metallic protective film in order to protect the silver mirror surface film and the metallic protective film and further improve the corrosion resistance and the durability. A coating material composition used at the time of applying coating material onto the metallic protective film and hardening the same to form the back paint film uses an amino modified epoxy resin obtained from amino alcohols having one aminogroup and at least one hydroxyl group in molecule and an epoxy chemical compound having the epoxy equivalent of 450-3000 as a binder.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved mirror that has excellent corrosion resistance, particularly salt spray resistance, and is easy to process such as cutting and chamfering.

[Prior Art] Conventionally, in mirrors made by plating a silver mirror film on the back surface of a glass substrate, in order to prevent the silver mirror film from discoloring or peeling due to water vapor, various corrosion-resistant gases, various chemicals, etc., or mechanical damage, A copper protective film was formed on the silver mirror film, and a backing film was formed by coating Komeitan, Bengara, lead cyanamide, calcium carbonate, or alkyd resin paints thereon.

However, although mirrors with backing coatings such as those mentioned above have their own effects, they do not provide sufficiently satisfactory performance against the adverse environments that exist under all conditions of use. Ta.

From this point of view, the present inventor attempted to use an epoxy resin paint as a back coating film in order to further improve corrosion resistance and durability. Backing coatings using epoxy resin paints are generally excellent in corrosion resistance and durability, and also have high adhesion to metal protective films such as copper, providing sufficiently higher corrosion resistance than conventional mirrors. However, another problem was discovered in the processing of the mirror.

In other words, when using a mirror, when cutting a large size mirror shipped from the factory into predetermined dimensions, or when chamfering the cut end of a mirror cut into a predetermined shape,
A problem was discovered in that the backing coating or silver mirror coating on the cut portion or chamfered portion, or both may peel off at the same time, resulting in a decrease in corrosion resistance and durability. Another problem has been found that when a large-sized mirror is cut into predetermined dimensions, the cutting is difficult and the cutting workability is reduced.

[Problems to be Solved by the Invention] An object of the present invention is to solve the above-mentioned problems of conventional mirrors on which backing coatings are formed using various types of paints, and to solve the problems described above when cutting or chamfering mirrors. To provide a mirror with excellent corrosion resistance, particularly salt spray resistance, and processability, in which the backing coating or silver mirror surface film of the mirror does not peel off, or the mirror has good releasability after cutting.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and provides a mirror formed by sequentially forming a silver mirror film on a glass substrate and a metal protective film on the film. On the metal protective film, an amino alcohol having one amino group and at least one hydroxyl group in the molecule and an epoxy equivalent of 450 to 3000 are added.
The present invention provides an improved mirror characterized in that a backing coating film is formed by coating and curing a coating material having as a binder an amino-modified epoxy resin obtained from an epoxy compound.

The present invention will be explained in more detail below.

FIG. 1 shows a specific example of a mirror according to the present invention, in which 1 is a glass substrate, 2 is a silver mirror film formed on the glass substrate, and 3 is a silver mirror film 2 for increasing the chemical durability. 4 shows a metal protective film formed on a silver mirror surface, and 4 shows a back coating film formed on a metal protective film to protect the silver mirror surface film and the metal protective film and further improve corrosion resistance and durability.

In the above-mentioned mirror, the silver mirror film is usually formed by depositing a film on the glass substrate surface using an electroless plating method, but it is not necessarily limited to this method, and may include vacuum evaporation method, sputtering method, etc. Silver films formed by various film forming methods can also be used as mirror films. This silver mirror film has a silver mirror film of 0.5 in order to obtain a sufficient reflectance required for a mirror and a silver mirror film with excellent durability.
A film thickness of ~2 g/m2 is suitable.

In addition, the metal protective film is formed as a protective film to increase the chemical durability of the silver mirror film, which is prone to chemical deterioration. Preferably, a metal that can be easily formed by a film forming method similar to that of a silver mirror film, such as an electroless plating method, is selected. A typical metal protective film is a copper protective film, and other metal protective films such as non-alloys, nickel, nickel alloys, tin, and tin alloys can also be used. Note that the metal protective film may be a single layer, or may be a combination of two or more layers of different metals. The thickness of such a metal protective film is preferably about 0.1 to 1 g/m2 in order to obtain a sufficient chemical durability effect and not to impair the adhesion to the silver mirror film. be.

A typical manufacturing method for mirrors with a silver mirror film and a metal protective film is to prepare a glass plate with a smooth surface and no surface defects, thoroughly wash the glass plate, and then remove the silver mirror film. A silver plating solution that deposits silver is sprayed on the surface by an electroless plating method, for example, a so-called silver mirror reaction, to form a silver mirror film, and then Cu, Cu, An example of this method is to spray a metal plating solution that deposits metals such as Ni and Sn or alloys thereof to form a metal protective film, and then wash and dry it, but various other methods can also be used.

In the present invention, in order to improve the corrosion resistance and mechanical durability of the silver mirror layer film and the metal protective film, the following paint is applied on the metal protective film and cured to form a backing film. .

The coating composition used in the present invention comprises: (1) an amino alcohol having one amino group and at least one hydroxyl group in the molecule; (2) an epoxy compound having an epoxy equivalent of 450 to 3,000; The binder is an amino-modified epoxy resin obtained from

Representative examples of the amino alcohols serving as the component (1) include monoethanolamino, jetanolamino, N-methylmonoethanolamino, diisopropanolamino, and aminodibenzyl alcohol. These may be used alone or as a mixture of two or more.

The epoxy resin as component (2) is, for example, a commercially available bisphenol type epoxy resin such as Epicoat 828, manufactured by Yuka Shell Chemical Co., Ltd. 834. 836° 1001. Same 1004. Same DX-
255, trade name Araldite G manufactured by Ciba Geigy Co., Ltd.
Y-260. Product name: DER3 manufactured by Dow Chemical Co., Ltd.
30, 331. 337: Part name manufactured by Dainippon Ink and Chemicals Co., Ltd. Evicron 800; Novolac type epoxy resin, such as Epicoat 152, manufactured by Yuka Shell Chemical Co., Ltd. 154: Trade name manufactured by Dow Chemical Co., Ltd. DEN431. 438; As a polyglycol type epoxy resin, for example, Araldite CT508 manufactured by Ciba Geigy Co., Ltd. Trade names DER732 and DER736 manufactured by Dow Chemical Co., Ltd.; Ester-type epoxy resins such as Eviclon 200 and 400 manufactured by Dainippon Ink and Chemicals; epoxidized polybutadiene manufactured by Nippon Soda Co., Ltd. Product name BF-1000 manufactured by Sumitomo Chemical Co., Ltd.; Product name Sumikaoil #5 manufactured by Sumitomo Chemical Co., Ltd.
0 ; Adeka Argus Chemical Co., Ltd. as epoxidized oil
Product name: ADEKA SIZER O-1SO, ADEKA SIZER 0-130
P; etc. can be mentioned.

Furthermore, it should be noted that epoxy compounds and derivatives of the above-mentioned epoxy resins that can be easily inferred from these compositions are also included within the scope of the present invention. Examples include polyol type epoxy resins, alicyclic epoxy resins, halogen-containing epoxy resins, and the like.

These can be used alone or as a mixture of two or more.

The epoxy resin has an epoxy equivalent of 450 to 3000.
In addition, the weight average molecular weight must be within the range of 60
Those in the range of 0 to 8000 are preferred.

The amino-modified epoxy resin used in the present invention preferably has 0.5 of amino groups per chemical equivalent of epoxy groups.
The above (1) component and (2) component are mixed in a ratio of ~2.0, preferably 0.8 to 1.5 chemical equivalents, and 50 to 2.
The desired product can be obtained by heating at 50°C, preferably 80 to 200°C, in the presence or absence of a solvent. The amino-modified epoxy resin used in the present invention can be easily produced as described above, and examples include Evicron H-303-45. Ebichron EXA-123
, Ebikuron H-371-i, Ebikuron H-360
.

Commercially available products such as Ebikuron H-353 and Ebikuron H-157 (both trade names manufactured by Dainippon Ink and Chemicals Co., Ltd.) may be used.

The amino-modified epoxy resin has a weight average molecular weight of about 20
000 to about 40,000, and preferably has a hydroxyl value of about 70 to 140.

The amino-modified epoxy resin itself is sufficiently useful as a coating material, but if necessary, it may be used in combination with other binders such as epoxy resins, alkyd resins, polyester resins, acrylic resins, polyvinyl butyral, rosin, petroleum resins, etc. You may do so.

Furthermore, the coating composition used in the present invention may optionally contain extender pigments such as talc, barium sulfate, mica, calcium carbonate, and pallite powder; titanium oxide, zinc white, red oxide, yellow lead, chromium oxide, and pallite powder. Coloring pigments such as iron, ultramarine blue, phthalocyanine blue, carbon black, and iron black; anticorrosive pigments such as calcium leadate, basic lead chromate, red lead, lead cyanamide, glass fiber, glass flakes, mica powder,
Reinforcing pigments such as asbestos and synthetic silica; other adhesives, rust preventives, suspending agents, hardening accelerators, etc. can be added.

Naturally, in order to dissolve or disperse each resin, a necessary amount of aromatic hydrocarbon, aliphatic hydrocarbon, ester, ether, ketone, or alcohol-based solvents may be added as necessary. Can be used.

In the present invention, when using pigments together, the pigment (P) and the binder (B) should be used together from the viewpoint of water resistance, acid resistance, etc.
The weight ratio P/B is preferably in the range of 1.0 to 4.6. Further, in particular, precipitated barium sulfate and talc are used as extender pigments in an amount of 15 to 25% by weight in the total paint composition, and the weight ratio of precipitated barium sulfate to talc is 30 to 70%.
/30 to 70, it is possible to further improve the adhesion, salt spray resistance, and chamferability of the coating film.

The coating composition thus obtained is coated onto the back surface of the mirror with a dry film thickness of 30 mm using a method such as a brush, roller, or spray flow coater.
Apply to a thickness of about 100 μm. Then, it is finished by heating and drying at room temperature or at a temperature below 250°C.

The adhesive strength of the backing coating film of the present invention is determined so that the silver mirror layer, the straightening coating film, or both do not peel off at the same time when cutting or chamfering, or so that the releasability during cutting is good. ranges from 5 to 13 kg/cm2, elongation rate is 0
．． 05-0.5%, stress is 1. (1~2.5kg/mm
2. The optimum elastic modulus is in the range of 500 to 1000 kg/mm''.

Next, examples of the present invention will be shown.

[Example] Thoroughly cleaned glass substrate (size: 72 mm x
A silver plating solution consisting of a solution containing silver nitrate that deposits silver by a silver mirror reaction and a reducing solution that reduces silver is sprayed onto a surface (36 mm x 5 mm) to form a silver mirror film with a thickness of 1 g and 7 m2, and after washing this film surface with water, A copper plating solution consisting of a solution containing copper sulfate that deposits copper and a reducing solution that reduces copper is sprayed by an electroless plating method to form a metal protective film made of copper with a thickness of 0.30 g/m, and then washed with water. Then it was dried.

Paint compositions (Examples 1 to 5 and Comparative Examples) with various formulations shown in Table 1 were dried on the copper protective film of the glass plate on which the silver mirror film and bronze statue protective film were formed using a flow coater method. Coat to a thickness of 30 μm and heat the glass plate to 8.
Baking was performed at 0° C. for 5 minutes to form a dry film with a thickness of 25 μm, and further baking was performed at a glass plate temperature of 135° C. for 5 minutes to obtain various test pieces.

Table 2 shows the results of various performance tests performed on these various test pieces.

Note 1) Manufactured by Dainippon Ink Chemical Industry ■Product name Ebikuron H
-303-45 [Weight average molecular weight 310,000, hydroxyl value 120, non-volatile content 45%] Note 2) Same as above Product name Evicron H-157 [Weight average molecular weight 250,000, hydroxyl value 75, non-volatile content 40%] Note 3) Same as above Product name
Evicron H-360 [weight average molecular weight 250,000,
Hydroxyl value 76, nonvolatile content 40%] Note 4) Bisphenol type epoxy resin [epoxy equivalent 45o] Note 5) Curing agent [polyamide resin 6.0 parts by weight, n-butano-
Rumi. o parts by weight and 3.0 parts by weight of xylene] were mixed.

2 - Certification Performance Test Method 1, Basic Test; Conducted according to JIS K 54006.15, and the evaluation is based on 10 points.

2. Warm water immersion: No abnormality should be observed on the silver surface when immersed in pure water at 60°C for 240 hours and taken out.

3. Steam test: No abnormality should be observed on the silver surface when exposed to 60″C steam for 240 hours and taken out.

4. Hydrogen sulfide gas test: No abnormality should be observed on the silver surface when exposed to 20℃ for 48 hours in a desiccator saturated with hydrogen sulfide gas and taken out.

5. Soaked in hydrochloric acid for 20 hours. 5% wt hydrochloric acid (grade 1 reagent) in water for 20 hours.
After soaking at ℃ for 72 hours, no abnormality should be observed on the silver surface when taken out. However, the four sides of the test piece were sealed.

6. Soaking in caustic soda water: 4%wt, caustic soda (grade 1 reagent) Soaking in water at 20°C for 48 hours and taking it out, no abnormality should be observed on the silver surface.

7. Ammonia water immersion; Ammonia water (1st class reagent) 50
When immersed in a mixture of 50 parts by weight and 50 parts by weight at 20°C for 48 hours and taken out, no abnormality should be observed on the silver surface.

8. Formalin immersion; 20°C in formalin (1st class reagent)
, When taken out after immersion for 240 hours, no abnormalities should be observed on the silver surface.

9. Bleach immersion: No abnormality should be observed on the silver surface when immersed in Lion Co., Ltd. product "Kitchen Bright" at 20°C for 48 hours and taken out. However, the four sides of the test piece were sealed.

10. Detergent immersion: No abnormality should be observed on the silver surface when immersed in Sunball Co., Ltd. product "Sunball" (Patent No. 1249719) at 20°C for 48 hours and taken out. However, the four sides of the test piece were sealed.

11. Salt spray test: No abnormality should be observed on the silver surface after 288 hours of salt spray test according to JIS Z 2371.

12. Accelerated weathering test, JIS K 54006.17
No abnormality was observed on the silver surface after 240 hours of accelerated weathering test, and the coating film had no wrinkles, blisters, cracks, or peeling, and the degree of chalking was small.

13. Cutting edge test; 24″ x 18″ at cross cutting part
(Thickness 5mm) When dividing a test piece into 4 pieces of 12" x 9", after inserting the cutting line, place a toothpick below the cutting line, fold the presser plate from above, and then raise the toothpick until the separation height is 50mm. The following were passed.

141 Chamfering test: After heating at 120° C. for 1 hour, chamfering is performed with a back chamfer width of 3 mm and a speed of 25 mm/min, and the presence or absence of peeling of the etched portion is determined. (No peeling: 2 passes, peeling: fail) 15. Pot life, tested according to JIS K 5664 Tar Epoxy Resin Paint 5.8 Pot Life.

16. Soaking in boiling water: No abnormality should be observed on the silver surface when soaked in pure water at 100°C for 18 hours and taken out.

[Operations and Effects of the Invention] The mirror according to the present invention has good adhesion to a metal protective film, and has chemical durability such as water vapor resistance, water resistance, alkali resistance, acid resistance, formalin resistance, and hydrogen sulfide resistance. It has a backing coating that has excellent mechanical properties such as adhesive strength, breaking strength, and impact resistance, and because the epoxy resin is modified with amino alcohol, the coating has a Flexibility, elasticity, stretchability, and separability are added, and the hardness of the backing coating, extreme adhesion with the metal protective film, residual stress, coefficient of thermal expansion, etc. are adjusted, making it easy to cut the mirror. The back coating, metal protective film, or silver mirror film on the cut or chamfered part will not peel off during cutting or chamfering, and the removability after cutting the mirror is good, and there is no mechanical damage. There are also few.

Additionally, the coating composition used in the present invention has no limitations on pot life due to its -liquid nature, and is particularly superior in salt water spray resistance compared to conventional two-component epoxy resin coatings. The quality has been further improved.

As described above, according to the present invention, a mirror having excellent corrosion resistance, durability, and workability can be obtained.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a mirror according to an example of the present invention. 1. Glass substrate, 2: Silver mirror film, 3: Metal protective film, 4: Back coating film! Figure 1 Procedural amendment dated October 17, 1999

Claims (2)

[Claims] (1) In a mirror formed by sequentially forming a silver mirror film on a glass substrate and a metal protective film on the film, an amino acid having one amino group and at least one hydroxyl group in the molecule is formed on the metal protective film. Alcohols and epoxy equivalents are 450 to 300
1. An improved mirror characterized in that a back coating film is formed by applying and curing a paint containing as a binder an amino-modified epoxy resin obtained from an epoxy compound of No. 0. (2) The paint contains precipitated barium sulfate and talc of 30 to 7
Extender pigment with a ratio of 0/70 to 30 (weight ratio)
The improved mirror of claim 1, wherein the paint contains 5 to 25% by weight.