TWI762785B - Mirror back coating composition without copper process and method for forming the same - Google Patents

Abstract

The present invention provides an epoxy resin-based coating composition; an epoxy resin derivative-based coating composition, and in particular, an improved copper- and lead-free component-free mirror back coating composition. Tests have shown that the mirror surface corrosion resistance of the mirror surface back coating composition of the present invention is not only better than that of the mirror surface protected by the general mirror surface back coating composition, but also better than the previous generation mirror surface back coating composition of the present invention.

Description

Mirror surface back coating composition without copper process and method for forming the same

The present invention relates to an epoxy resin-based coating composition; an epoxy resin derivative-based coating composition, and particularly to a copper- and lead-free component-free mirror back coating composition.

Everyone must use the mirror in their daily life. The reaction between the paint on the back of the mirror and the silver mirror is a key factor in determining the quality of the mirror. Only the lead-containing manufacturing process causes a burden on people's living environment.

The general mirror making process is as follows.

Cleaning step: cleaning the glass layer, and processing the glass surface into a clean surface.

Sensitization step: the glass layer is sensitized with a tin chloride aqueous solution to sensitize the surface of the glass layer; the glass layer is washed with water to remove the tin chloride aqueous solution remaining in the reaction.

Silver coating layer step: silver nitrate is in contact with the reducing liquid phase, so that the surface of the glass layer is coated with a silver coating layer.

Copper coating layer step: spray copper sulfate and reducing solution (such as iron powder, zinc powder) on the silver coating layer to form a copper coating layer.

Finally, the mirror back paint (back paint, single layer or double layer) must be applied on the copper film layer. A protective layer is formed, and because of the chemical characteristics, the protective layer must be a lead-containing mirror back paint, so that the mirror has the characteristics of corrosion resistance and prolonged aging.

Therefore, general mirror coatings generally contain copper and lead components, especially coatings containing lead components. In addition to economic development, more and more attention is paid to environmental protection issues, whether it is process or finished products. Environmental regulations It is also getting stricter.

The problem to be solved by the present invention is generally that the mirror coating contains copper and lead-containing components, and needs to be coated with one or more layers of coatings.

The present invention provides a mirror-surface back coating composition, which is a protective layer, and the manufacturing steps are as follows.

Cleaning step: cleaning the glass layer, and processing the surface of the glass layer into a clean surface.

Sensitization step: the glass layer is sensitized with a tin chloride aqueous solution to sensitize the surface of the glass layer; the glass layer is washed with water to remove the tin chloride aqueous solution remaining in the reaction.

Adhesion promotion step: Use metal chloride to react with the sensitizing layer.

Silver plating step: silver nitrate is in contact with the reducing liquid phase, so that a layer of silver film is plated on the surface of the glass layer.

Passivation step: Use metal chloride to react with silver film.

Mirror back coating steps: apply one, two or para-layer mirror back coating composition after passivation process to protect the silver film layer.

In order to achieve the above purpose, the present invention discloses a mirror-surface back coating composition, which is a protective layer and includes an epoxy resin, the epoxy resin has more than two epoxy groups -CH(O)CH-, benzene The groups -C ₆ H ₅ and n are (-CH ₂ -) _n groups of 2-8; and a hardener, the epoxy resin and the hardener are mixed and hardened to form a cured product.

In order to achieve the above purpose, the present invention discloses a mirror-surface back coating composition, which is a protective layer and includes an epoxy resin, and the epoxy resin has more than two epoxy-CH(O)CH-, phenyl- C ₆ H ₅ , at least n is a (-CH ₂ -) _n group of 2 to 8, containing two or more epoxy groups and reacts with a phenyl group and a (-CH ₂ -) _n group to form a cross-linked structure The cured product; and a hardener, the epoxy resin and the hardener are mixed and hardened, and analyzed by thermal desorption instrument tandem gas chromatography mass spectrometer (TD-GC-MS), at a reaction temperature of 350 ° C, in the layer Analysis of spectrum detection analysis has the cleavage of benzene ring derivatives.

In order to achieve the above purpose, the present invention discloses a mirror-surface back coating composition, comprising an epoxy resin, and the epoxy resin has more than two epoxy groups-CH(O)CH-, phenyl-C ₆ H ₅ , at least n is a (-CH ₂ -) n group of 2 to 8, and contains two or more epoxy groups after reacting with a phenyl group and a (-CH ₂ -) _n group to generate a cured product with a cross-linked structure; and a hardener, the epoxy resin is mixed with the hardener to harden, and is analyzed by a thermal desorption instrument in series with a gas chromatography mass spectrometer. At a reaction temperature of 750° C., the chromatographic spectrum detects and analyzes that it has a cracked benzene ring derivative.

As mentioned above, the thickness of the protective layer is between 30 and 60 microns.

The above-mentioned protective layer is coated on the silver film layer by a curtain coating (Curtain Coating).

The above-mentioned protective layer further comprises a composite metal phosphate pigment added in any combination of aluminum, zinc, iron, titanium, tin, and nickel, which accounts for 10-30 weight percent of the mirror back coating composition.

Another object of the present invention is to provide a method for forming a mirror-surface back coating composition, comprising an epoxy resin, a hardener and a composite metal phosphate pigment, wherein the epoxy resin is a ring with an epoxy equivalent of 200 to 1200. Oxygen resin, the hardener is added in a proportion of 2 to 12 (Parts per hundred parts of resin, Phr), and additionally adds aluminum, zinc, iron, titanium, tin, 10 to 30 weight percent of the mirror back coating composition A composite metal phosphate pigment with any combination of nickel, the epoxy resin is mixed with the composite metal phosphate pigment, and the user adds the hardener and mixes well before use to harden to form a protective layer, or the composite metal phosphate The pigment is mixed with the hardener first, and the user then adds the epoxy resin and mixes well before use, and it hardens to form a protective layer.

Another object of the present invention is to provide a method for forming a mirror-surface back coating composition, comprising an epoxy resin, a hardener and a composite metal phosphate pigment, wherein the epoxy resin is a ring with an epoxy equivalent of 200 to 1200. Oxygen resin, the hardener accounts for 2% to 12% by weight of the mirror back coating composition, and additionally adds any combination of aluminum, zinc, iron, titanium, tin, and nickel that accounts for 10 to 30 weight percent of the mirror back coating composition For composite metal phosphate pigments, the epoxy resin is mixed with the composite metal phosphate pigments, and the user adds the hardener and mixes well before use to form a protective layer, or the composite metal phosphate pigments are mixed with The hardener is mixed evenly, and the user adds the epoxy resin to mix well before use, and then hardens to form a protective layer.

As mentioned above, the thickness of the protective layer is between 30 and 60 microns.

The above-mentioned protective layer is coated on the silver film layer by a curtain type.

The effect of the invention after the improvement of this product is mainly manifested in: 1. The mirror back coating composition has only one layer, and the operator only needs to monitor one device; 2. The drying energy consumption is reduced by 12.5%, and the thickness of the back paint is reduced by about 10 μm; 3. The corrosion width of the test piece after 96 hours of acid resistance test with 5% hydrochloric acid Relatively only one-seventh of that before the improvement; 4. Environmentally friendly lead-free (lower than the limit of testing equipment 2ppm).

1: Mirror

10: Glass layer

20: silver film layer

30: Protective layer

Fig. 1 is a schematic cross-sectional view of the mirror surface structure of an embodiment of the mirror back coating composition of the present invention; Fig. 2 is the corrosion of the silver layer of the test piece (mirror surface) after the test pieces of the experimental group and the control group are immersed in a 5% hydrochloric acid solution for different days Figure 3 shows the degree of peeling of the test piece (mirror back) after immersion in 5% hydrochloric acid solution for different days in the experimental group and the control group; Figure 4 shows the acid resistance test result of 5% hydrochloric acid in the present invention.

The present invention adopts Fourier transform infrared spectrometer for analysis, which is an indispensable qualitative tool for material analysis or compound structure. After Fourier Transfer, an infrared absorption spectrum is generated. Fourier transform infrared spectrometer absorbs the peak at the position of the spectrum, and uses the fingerprint region after 1400 cm ^-1 to identify the substance of the present invention, which can effectively and accurately obtain accurate data.

Example 1

Mirror surface back coating composition is a protective layer, comprising an epoxy resin, the epoxy resin has more than two epoxy groups-CH(O)CH-, phenyl-C ₆ H ₅ and n is 2~ (-CH ₂ -) _n group of 8; and a hardener, the epoxy resin and the hardener are mixed and hardened to form a cured product.

The embodiment of the present invention adopts a thermal desorption instrument in series with a gas chromatography mass spectrometer for analysis, and the Since each compound has a unique or nearly unique mass spectrum, the components in the gas are captured and analyzed by a thermal desorption instrument to determine the mass spectrum qualitatively and peak area quantitative mass spectrometry data analysis for identification.

Example 2

A mirror-surface back coating composition, comprising an epoxy resin, the epoxy resin has more than two epoxy groups-CH(O)CH-, phenyl-C ₆ H ₅ , and at least n is (- CH ₂ -) _n group, which contains two or more epoxy groups and reacts with phenyl and (-CH ₂ -) _n groups to form a cured product with a cross-linked structure; and a hardener, the epoxy resin and The hardener is mixed and hardened, and the back surface of the coating or the contact surface of the silver layer is sampled and analyzed by a thermal desorption instrument in series with a gas chromatography mass spectrometer. With cleavage of benzene ring derivatives.

As mentioned above, the optimal chromatogram is between 15.5 minutes and 18.5 minutes.

Example 3

In order to achieve the above purpose, the present invention discloses a mirror-surface back coating composition, comprising an epoxy resin, and the epoxy resin has more than two epoxy groups-CH(O)CH-, phenyl-C ₆ H ₅ , at least n is a (-CH ₂ -) _n group of 2 to 8, and contains two or more epoxy groups after reacting with a phenyl group and a (-CH ₂ -) _n group to generate a cured product with a cross-linked structure; And a hardener, the epoxy resin and the hardener are mixed and hardened, the back surface of the coating or the contact surface of the silver layer is sampled, and analyzed by a thermal desorption instrument in series with a gas chromatography mass spectrometer. The spectrum detection analysis has the split benzene ring derivative, and the chromatographic spectrum detection analysis has the split benzene ring derivative between 7 minutes and 21 minutes.

Optimally, the chromatogram is between 8 and 18 minutes.

As mentioned above, the thickness of the protective layer is between 30 and 60 microns.

The above-mentioned protective layer is coated on the silver film layer by a curtain type.

The above-mentioned protective layer further comprises the composite metal phosphate pigment of any combination of aluminum, zinc, iron, titanium, tin and nickel components that accounts for 10 to 30 weight percent of the mirror back coating composition. The composite metal phosphate pigment can be used. One component of aluminum, zinc, iron, titanium, tin, nickel, or two or more components of aluminum, zinc, iron, titanium, tin, nickel, or more kinds of aluminum, zinc, iron, titanium, tin, The nickel component is mixed.

Example 4

Add 5 weight percent of nickel metal phosphate pigment and 10 weight percent of iron metal phosphate pigment in the mirror back coating composition, and mix to form 15 weight percent of composite nickel iron metal phosphate pigment.

Example 5

Add 2 weight percent of nickel metal phosphate pigment, 3 weight percent of iron metal phosphate pigment and 5 weight percent of zinc metal phosphate pigment, which account for 2 weight percent of the mirror back coating composition, and mix into 10 weight percent of composite nickel-iron-zinc metal phosphoric acid salt paint.

Example 6

Another object of the present invention is to provide a method for forming a mirror-surface back coating composition, which includes an epoxy resin, a hardener and a composite metal phosphate pigment. The epoxy resin is an epoxy resin with an epoxy equivalent of 200 to 1200, the hardener is added in a mixing ratio of 2 to 12, and a composite zinc-aluminum metal phosphate pigment is added that accounts for 10 weight percent of the mirror back coating composition. , the epoxy resin is mixed with the composite zinc-aluminum metal phosphate pigment, and the user adds the hardener and mixes well before use to form a protective layer, or the composite zinc-aluminum metal phosphate pigment is first mixed with the hardened The epoxy resin is mixed evenly, and the user adds the epoxy resin and mixes it well before use, and it hardens to form a protective layer.

1 is a schematic cross-sectional view of the structure of a mirror surface 1 according to an embodiment of the mirror surface back coating composition of the present invention, a mirror surface 1 at least includes a glass layer 10; a silver film layer 20 is formed on an upper surface of the glass layer 10; The protective layer 30 is formed on the upper surface of the silver film layer 20, wherein the protective layer 30 is a composition of a mirror-surface back coating. Wherein, the thickness of the protective layer 30 is between 30 and 60 microns.

Example 7

Another object of the present invention is to provide a method for forming a mirror-surface back coating composition, which includes an epoxy resin, a hardener and a composite titanium nickel metal phosphate pigment. The epoxy resin is an epoxy resin with an epoxy equivalent of 200 to 1200, the hardener accounts for 2% to 12% by weight of the mirror back coating composition, and an additional 30% by weight of the mirror back coating composition is added. Mix composite titanium-nickel metal phosphate pigment (metal titanium phosphate pigment: metal nickel phosphate pigment is mixed at a weight percentage of 1:2), mix the epoxy resin with the mixed composite titanium-nickel metal phosphate pigment, and the user is using Add the hardener and mix well and then harden to form a protective layer, or the mixed composite titanium-nickel metal phosphate pigment is mixed with the hardener first, and the user adds the epoxy resin and mixes well before use. form a protective layer.

1 is a schematic cross-sectional view of the structure of a mirror surface 1 according to an embodiment of the mirror surface back coating composition of the present invention, a mirror surface 1 at least includes a glass layer 10; a silver film layer 20 is formed on an upper surface of the glass layer 10; The protective layer 30 is formed on the upper surface of the silver film layer 20, wherein the protective layer 30 is a composition of a mirror-surface back coating. Wherein, the thickness of the protective layer 30 is between 30 and 60 microns, and the protective layer 30 is coated on the upper surface of the silver film layer 20 by a curtain type.

Example 8

5% hydrochloric acid acid resistance test: under normal temperature conditions, the experimental group test piece and the control group test piece of the present invention were immersed in 5% hydrochloric acid solution for 24 hours, 72 hours, and 96 hours to observe whether the test pieces had foaming, silver The phenomenon of layer corrosion and its degree of peeling.

Experimental group: the mirror surface back coating composition of the present invention adding a composite aluminum tin metal phosphate pigment is coated on the finished test piece of the mirror back; control group: the previous generation mirror surface back coating composition of the present invention is coated on the back of the mirror. The finished test piece on the back of the mirror.

The silver layer corrosion occurred in the control group at 72 hours, and the corrosion range of the silver layer expanded at 96 hours; while the experimental group did not have the same silver layer corrosion phenomenon as the control group at 72 hours and 96 hours.

2 is a graph showing the degree of corrosion and blackening of the silver layer of the test piece (mirror surface) after the test pieces of the experimental group and the control group are immersed in a 5% hydrochloric acid solution for different days.

Fig. 3 is a graph showing the degree of peeling of the test pieces (mirror back) after the test pieces of the experimental group and the control group of the present invention are immersed in a 5% hydrochloric acid solution for different days.

Figure 2 and Figure 3 are respectively the front and back sides of a mirror, Figure 2 is the mirror surface, Figure 3 is the back of the mirror, Figure 2 shows the degree of peeling off the silver layer of the mirror test piece and the corrosion and blackening of the silver layer, Figure 3 shows the mirror back test piece degree of peeling.

The left of Fig. 2: the front of the mirror sheet of the control group is dipped in 5% hydrochloric acid solution for 96 hours; the right of Fig. 2: the front of the mirror sheet of the experimental group of the present invention is dipped in a 5% hydrochloric acid solution for 96 hours; the left of Fig. 3: the back test of the mirror of the control group The reverse side of the sheet was immersed in a 5% hydrochloric acid solution for 96 hours; the right side of Figure 3: the reverse side of the mirror-back test piece of the experimental group of the present invention was immersed in a 5% hydrochloric acid solution for 96 hours.

Figure 4 is the test result of 5% hydrochloric acid acid resistance

1. When immersed in 5% hydrochloric acid solution for 24 hours, the corrosion width of the experimental group is 0.1mm, and the corrosion width of the control group is 0.7mm.

2. When immersed in 5% hydrochloric acid solution for 72 hours, the corrosion width of the experimental group is 0.15mm, and the corrosion width of the control group is 1.0mm.

3. When immersed in 5% hydrochloric acid solution for 96 hours, the corrosion width of the experimental group is 0.2mm, and the corrosion width of the control group is 1.5mm.

Between the test piece of the experimental group of the present invention and the control group, the difference can be seen in the 5% hydrochloric acid solution immersion test time in 24 hours, and as the immersion test time increases to 96 hours, the corrosion width of the test piece in the control group increases, and the silver The phenomenon of layer corrosion and blackening increases, and the degree of peeling is more obvious; while the test piece of the present invention has a good degree of corrosion resistance.

Example 9

Copper accelerated acetate spray test before modification

The aging and corrosion tests were carried out for the mirror back coating composition of the present invention, using "copper The experimental method of accelerated acetate spray test (CASS, Copper accelerated acetic acid salt spray test):

Experimental group A: The previous generation mirror of the present invention was adhered to the protective layer side of the back of the mirror with neutral silicone (Type N2 from Dow Corning), the diameter of the neutral silicone was 50 millimeters (mm) and the thickness was 1 mm (mm), and it was dried by giving it dry air for 24 hours.

Experimental group B: The previous generation mirror surface of the present invention was adopted, but the protective layer was changed to a double-layer back coating without lead - alkyd resin (Alkyd).

Adhere to the protective layer side of the back of the mirror with neutral silicone (Dow Corning's Type N2), the diameter of the neutral silicone is 50 millimeters (mm), the thickness is 1 millimeter (mm), and it is given 24 hours of dry air to make it. its dry.

The experimental group A and experimental group B were subjected to the "Copper Accelerated Acetate Spray Test". According to the ISO9227-1990 standard, the test duration was 120 hours. The test results are as follows:

Experimental group A: There are no white spots (corrosion spots) on the silver film layer.

Experimental group B: 10-15 white spots (corrosion spots) on the silver film layer.

Modified Copper Accelerated Acetate Spray Test

Experimental group C: the mirror surface of the present invention, a composite titanium-nickel metal phosphate pigment was added to the experimental group A.

The "Copper Accelerated Acetate Spray Test" was carried out on the experimental group A, the experimental group B and the experimental group C after the improvement of the invention. According to the ISO9227-1990 standard, the test duration was increased to 240 hours. The test results are as follows:

Experimental group A: There are 1~2 white spots (corrosion spots) on the silver film layer.

Experimental group B: 10-15 white spots (corrosion spots) on the silver film layer.

Experimental group C: There are no white spots (corrosion spots) on the silver film layer.

The mirror surface of the experimental group C of the present invention is fixed to any lens device site with neutral silicone gel in the simulated lens. When the place has high humidity and non-neutral gas and liquid exist. Tests have shown that the mirror surface corrosion resistance of the mirror surface back coating composition of the present invention is not only better than that of the mirror surface protected by the general mirror surface back coating composition, but also better than the previous generation mirror surface back coating composition of the present invention.

In summary, the present invention utilizes and provides a mirror back coating composition comprising a glass layer; a silver film layer formed on an upper surface of the glass layer; a protective layer, the protective layer is a mirror back coating The composition, the modified mirror back coating composition contains epoxy resin and hardener and composite metal phosphate pigments of aluminum, zinc, iron, titanium, tin, nickel in any combination, which is better than the previous invention, except that it can be used without Under the conditions of copper and lead components, it can achieve high wear resistance, corrosion resistance and prolonged aging effects, and lead-free components will not cause environmental burdens, so the cost can be greatly reduced.

The present invention merely presents the preferred embodiments or examples of the technical means used to solve the problem, and is not intended to limit the scope of the patent application of the present invention. Equivalent changes and modifications are all covered by the patent of the present invention.

1: Mirror

10: Glass layer

20: silver film layer

30: Protective layer

Claims (10)

A mirror-surface back coating composition is a protective layer, comprising an epoxy resin, the epoxy resin has more than two epoxy groups-CH(O)CH-, phenyl-C ₆ H ₅ and n is 2 (-CH ₂ -) _n groups of ~8; and a hardener, the epoxy resin and the hardener are mixed and hardened to form a cured product. A mirror-surface back coating composition is a protective layer, comprising an epoxy resin, the epoxy resin has more than two epoxy groups-CH(O)CH-, phenyl-C ₆ H ₅ and n is 2 (-CH ₂ -) _n groups of ~8; and a hardener, the epoxy resin and the hardener are mixed and hardened to form a cured product, which is analyzed by a thermal desorber in series with a gas chromatography mass spectrometer and reacted at 350°C Under the temperature, it has cracked benzene ring derivatives in the chromatographic analysis. A mirror-surface back coating composition is a protective layer, comprising an epoxy resin, the epoxy resin has more than two epoxy groups-CH(O)CH-, phenyl-C ₆ H ₅ and n is 2 (-CH ₂ -) _n groups of ~8; and a hardener, the epoxy resin and the hardener are mixed and hardened to form a cured product, which is analyzed by a thermal desorber in series with a gas chromatography mass spectrometer and reacted at 750°C Under the temperature, it has cracked benzene ring derivatives in the chromatographic analysis. The mirror-surface back coating composition according to any one of claims 1 to 3, wherein the thickness of the protective layer is between 30 and 60 microns. The mirror-surface back coating composition according to any one of claims 1 to 3, wherein the protective layer is coated on the silver film layer in a curtain-like manner. The mirror back coating composition according to any one of claims 1 to 3, wherein the protective layer further comprises iron, titanium, tin and nickel components added to account for 10 to 30 weight percent of the mirror back coating composition A composite metal phosphate pigment with any combination of at least two components in it. A method for forming a mirror surface back coating composition without copper process, the mirror surface back coating composition has an epoxy resin, a hardener and a composite metal phosphate pigment, wherein the epoxy resin has more than two rings Oxygen-CH(O)CH-, phenyl-C ₆ H ₅ and n are (-CH ₂ -) _n groups of 2 to 8; the composite metal phosphate pigment comprises a composite aluminum tin metal phosphate pigment and a composite At least one of titanium-nickel metal phosphate pigments, the epoxy resin is an epoxy resin with an epoxy equivalent of 200 to 1200, the hardener is added in a mixing ratio of 2 to 12 Phr, and is added to account for 10 ~ 10 ~ of the mirror back coating composition 30 weight percent of the composite metal phosphate pigment, mix the epoxy resin with the composite metal phosphate pigment, add the hardener and mix well, and then harden to form a protective layer, or the composite metal phosphate pigment is first mixed with the hardened The epoxy resin is mixed evenly, and then the epoxy resin is added and mixed to form a protective layer after hardening. A method for forming a mirror surface back coating composition without copper process, the mirror surface back coating composition has an epoxy resin, a hardener and a composite metal phosphate pigment, wherein the epoxy resin has more than two rings Oxygen-CH(O)CH-, phenyl-C ₆ H ₅ and n are (-CH ₂ -) _n groups of 2 to 8; the composite metal phosphate pigment comprises a composite aluminum tin metal phosphate pigment and a composite At least one of titanium nickel metal phosphate pigments, the epoxy resin is an epoxy resin with an epoxy equivalent of 200 to 1200, the hardener accounts for 2% to 12% by weight of the mirror back coating composition, and is added to account for the mirror surface. 10-30 weight percent of the composite metal phosphate pigment in the back coating composition, mixing the epoxy resin with the composite metal phosphate pigment, adding the hardener and mixing, and then hardening to form a protective layer, or the composite metal The phosphate pigment is first mixed with the hardener, and then the epoxy resin is added and mixed to form a protective layer after hardening. The formation method of the mirror-surface back coating composition of the copper-free process according to any one of claims 7 to 8 method, wherein the thickness of the protective layer is between 30 and 60 microns. The method for forming a mirror-surface back coating composition for a copper-free process according to any one of claims 7 to 8, wherein the protective layer is coated on the silver film layer in a curtain-like manner.

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