KR102121025B1 - High reflective silver coating method for vehicle lamp - Google Patents

Abstract

The present invention relates to a method for coating a lamp for a vehicle. The method for coating a lamp for a vehicle according to an embodiment of the present invention is provided to coat a silver coating reflective film on a surface of a substrate constituting a vehicle lamp. The silver coating reflective film is formed by firstly coating a lower thermosetting resin layer on the substrate, secondly coating a silver coating layer on the upper part of the lower thermosetting resin layer, and thirdly coating an upper thermosetting resin layer on the silver coating layer.

Description

{High reflective silver coating method for vehicle lamp}

The present invention relates to a method for coating a lamp for a vehicle. More specifically, it relates to a vehicle lamp coating method for improving adhesion and corrosion resistance of a silver coating layer coated on a surface of a substrate constituting a vehicle lamp.

For example, an aluminum mirror exhibiting high reflectance in a wide area of visible light is mainly used as a reflector having a high reflectance. The aluminum mirror has an average reflectance of about 90% in the visible region. However, if a higher reflectance is required, instead of an aluminum mirror, a silver mirror with an average reflectance of about 97% is used.

However, the silver mirror is easily oxidized or susceptible to wounds, and the adhesion to the substrate is very weak, so it is often necessary to install a hard coat layer on the top or bottom of the substrate or silver coating layer before coating on the substrate.

As a general method of coating a silver-coated reflective film on a substrate, it is divided into a vacuum deposition method (CVD/PVD) and a silver-coated reflective film coating method by a chemical reaction, but the vacuum deposition method is limited by expensive vacuum equipment and mass production. There is this.

In addition, the method of coating the silver-coated reflective film by wet chemical reaction is easy to mass-produce, but there is a problem in that environmental pollution caused by waste liquid or the like or adhesion of the silver coating layer to the substrate is deteriorated.

Here, the silver-reflection coating method using a silver mirror chemical reaction uses a thermosetting resin between the substrate and the silver coating layer or the silver coating layer and the upper hard coat layer to protect the silver coating layer, wherein the upper hard coat layer is cured When doing so, a problem may occur in the adhesion between the substrate and the undercoat layer between the silver coating layer.

This problem mainly occurs when the silver coating layer is exposed for a long time in a high temperature and high humidity environment.

On the other hand, the vehicle lamp is somewhat sealed to the outside, but requires durability against high heat, corrosive gas, salt water resistance, etc., as a power source LED.

Therefore, when the silver coating layer is coated on the surface of the substrate constituting such a vehicle lamp, adhesion tends to decrease, resulting in difficulty in coating the silver-coated reflective film, which acts as a handicapped person in practical application of the silver mirror.

Republic of Korea Patent Publication No. 10-2019-0051134

It is an object of the present invention to not only be able to easily coat the silver coating layer on the surface of the substrate constituting the vehicle lamp, but also to prevent the oxidation, salt resistance and adhesion of the silver-coated reflective film, thereby making the vehicle lamp coating easy. In providing a way.

Another object of the present invention is to provide a method for coating a lamp for a vehicle that can easily coat a silver coated reflective film on a surface of a waste plastic as well as a general plastic used as a base for a vehicle lamp.

In order to solve the above problem,

Vehicle lamp coating method according to an embodiment of the present invention is a vehicle lamp coating method for coating a silver coating reflective film on the surface of a material (Material) constituting the vehicle lamp,

First coating the lower thermosetting resin layer on the substrate, secondary coating the silver coating layer on the upper portion of the lower thermosetting resin layer, and tertiary coating of the upper thermosetting resin layer on the upper portion of the silver coating layer to provide the silver coating reflective film. Will be configured.

Here, the vehicle lamp according to an embodiment of the present invention may be a head lamp (headlight) or a tail lamp (taillight).

In addition, the substrate according to an embodiment of the present invention may be a general plastic (General Plastic) or waste plastic (Recycle plastic). In addition, the general plastic may be general polycarbonate, and the waste plastic may be waste polycarbonate.

In addition, in the vehicle lamp coating method according to an embodiment of the present invention, the lower thermosetting resin layer uses a liquid epoxy resin, an unsaturated polyester resin, a fluorine resin, an acrylic resin, a melamine resin, a polymer of silicone acrylic resin, or an oligomer. And, an isocyanate compound or an amine compound can be used as a curing agent.

In addition, in the vehicle lamp coating method according to an embodiment of the present invention, the lower resin coating liquid for forming the lower thermosetting resin layer is a liquid epoxy resin, unsaturated polyester resin, fluorine resin, acrylic resin, melamine resin, silicone acrylic Dissolve the polymer or oligomer of the resin in an organic solvent and apply it to the substrate by air spray, but as the solvent, xylene, nucleic acid, ethyl alcohol, methyl alcohol, butyl acetate or methyl isobutyl ketone can be used.

In addition, in the method for coating a lamp for a vehicle according to an embodiment of the present invention, before forming the silver coating layer, 0.1 to 0.5 mol/L of tin chloride and stannous chloride on the lower thermosetting resin coating layer and 0.1 to 0.5 mol of hydrogen peroxide/ The mixed solution diluted with ℓ is applied by an air spray method, but the mixing ratio of the first tin chloride and tin tin chloride may be 2 to 3:1.

In addition, in the lamp coating method for a vehicle according to an embodiment of the present invention, after the activation treatment with the mixed solution, an activation treatment with silver ions is performed, wherein the silver ions are diluted with silver nitrate solution to 0.01 mol/L or less. The solution can be applied to a surface treated with first tin chloride or tin chloride.

In addition, in the vehicle lamp coating method according to an embodiment of the present invention, the silver coating solution for the formation of the silver coating reflective film coating layer is composed of an ammoniaous silver nitrate or silver carbonate solution and a reducing agent solution containing a reducing agent and a strong alkali component, respectively. It may be mixed with each other immediately before the spraying operation and applied to the lower thermosetting resin coating layer on which the activation treatment has been performed.

These solutions will become more apparent from the specific details for carrying out the following invention based on the accompanying drawings.

Prior to this, the terms or words used in the specification and claims should not be interpreted in a conventional and lexical sense, and the inventor may properly define the concept of terms in order to best describe his or her invention. Based on the principle of being able to be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

According to an embodiment of the present invention, it is possible to provide a vehicle lamp having a high reflectance by easily coating a silver-coated reflective film on a substrate constituting the vehicle lamp.

In addition, according to an embodiment of the present invention, as well as a general plastic used as a substrate for a vehicle lamp, the surface of the waste plastic can be easily coated with a silver coating reflective film, thereby effectively reducing the cost for manufacturing a vehicle lamp. You can.

The specific aspects and specific technical features of the present invention will become more apparent from the following specific contents and embodiments associated with the accompanying drawings. In addition, in addition to reference numerals to the components of each drawing in this specification, it should be noted that the same components have the same reference numerals as possible even though they are displayed on different drawings. In addition, in describing an embodiment of the present invention, when it is determined that detailed descriptions of related well-known structures or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. When a component is described as being "connected", "coupled" or "connected" to another component, the component may be directly connected to or connected to the other component, but another component between each component It will be understood that elements may be "connected", "coupled" or "connected".

Hereinafter, a method for coating a lamp for a vehicle according to an embodiment of the present invention will be described in detail as follows.

Vehicle lamp coating method according to an embodiment of the present invention is for coating a silver-coated reflective film by a silver-mirror chemical reaction on the surface of a material that is made of general plastic or recycled plastic. It relates to a coating method.

Here, the vehicle should be interpreted as meaning including all vehicles driving on the road, that is, commercial vehicles, passenger cars, vans, freight cars, special cars, two-wheel vehicles, and bicycles. In addition, the vehicle lamp may be a head lamp (headlight) or a tail lamp (rear light).

In addition, the base material constituting the vehicle lamp may be ordinary plastic or waste plastic. In addition, the general plastic may be general polycarbonate, and the waste plastic may be waste polycarbonate. In this case, the general should be interpreted as not being recycled, which is the opposite of recycling.

Therefore, according to an embodiment of the present invention, as well as general plastic, it is possible to easily form a silver-coated reflective film on the surface of the waste plastic, thereby effectively reducing the cost for manufacturing a vehicle lamp.

On the other hand, in the vehicle lamp coating method according to an embodiment of the present invention, in order to improve adhesion between the lower thermosetting resin layer constituting the silver coating reflective film and the substrate, pre-treating the substrate before coating the lower thermosetting resin layer Is done.

The pre-treatment method may be carried out by a wet method such as detergent, solvent or ultrasonic cleaning, and a dry method such as corona discharge, ultraviolet irradiation, electron beam irradiation, and the like.

In addition, the manufacturing method of the lower resin coating liquid for forming the lower thermosetting resin layer is described by dissolving liquid epoxy resin, unsaturated polyester resin, fluorine resin, acrylic resin, melamine resin, silicone acrylic resin, etc., which are thermosetting resins in an organic solvent. It is applied to the surface of the.

Here, the composition of the lower resin coating solution is 30 to 50% by weight of acrylic resin and 10 to 20% by weight of epoxy resin.

In addition, xylene, nucleic acid, ethyl alcohol, methyl alcohol, butyl acetate, methyl isobutyl ketone (MIBK), or the like can be used as the solvent.

That is, silane coupling agent is added to the solution adjusted to a viscosity of about 30-40 cPs by mixing 5-10 wt% of methyl isobutyl ketone (MIBK), 5-25 wt% of xylene, and 5-25 wt% of butyl acetate as the solvent. The mixed solution by adding 0.1 to 1.0% by weight is applied to the substrate in a thickness of about 10 to 20 μm by air spraying.

For example, the silane coupling agent is, for example, 3-(acryloxypropyl) trimethoxysilane, 3-acryloxyethyl-dimethoxysilane as an acrylate and metaacrylate trialkoxy or dialkoxy functional silane, triehtoxysilyundecanol, triethoxysilyudecanal ethlene glycol as an aldehyde functional silane, epoxy functional silane As 2-(3,4 epoxycyclohexyl) ethyl triethoxysilane, 3-(glycidoxypropyl) trimethoxysilane, etc., about 0.1 to 2.0 wt% of the total amount of the lower resin coating solution is added.

A silver coating layer is formed on the lower thermosetting resin layer formed of the lower resin coating layer.

However, before forming the silver coating layer, 0.1 to 0.5 mol/L of first tin chloride (SnCl ₂ ) and tin chloride (SnCl _{4 ·} 5H ₂ O) on the lower thermosetting resin layer, hydrogen peroxide (H ₂ O ₂ ) 0.1 ~ The mixed solution diluted to 0.5 mol/L can be applied by an air spray method. The mixing ratio of stannous chloride and stannous chloride may be composed of 2 to 3:1.

In addition, after the activation treatment with the tin chloride solution, an activation treatment with silver ions may be performed, and the silver ions may be diluted with silver nitrate solution to about 0.01 mol/L or less with tin chloride or tin chloride. It is desirable to apply to the surface.

On the other hand, the silver coating solution for the formation of the silver-coated reflective film according to an embodiment of the present invention is composed of an ammoniaous silver nitrate or silver carbonate solution and a reducing agent solution containing a reducing agent and a strong alkali component, respectively, mixed with each other immediately before spraying to activate treatment Is applied to the lower thermosetting resin layer.

Here, as the reducing agent, aqueous solutions such as aldehyde compounds such as glycol and glyoxal, hydrazine sulfate, hydrazine carbonate, sodium sulfite, and sodium thiosulfate may be preferable.

In addition, the composition of the silver coating reflective film is separately composed of a silver coating solution and a reducing agent solution. The composition of the silver coating solution is 3-10 g of silver nitrate, 10-25 ml of ammonia (30% solution), 4-10 g of caustic soda, 1000 ml of deionized water It can be composed of.

The reducing agent solution may be composed of hydrazine sulfate (N ₂ H ₄ + H ₂ SO ₄ → N ₂ H ₆ SO ₄ ) 1-5 g, citric acid 0.1-0.5 g, alcohol 20-100 ml, and deionized water 100 ml .

In addition, the same thermosetting resin layer as the lower thermosetting resin layer primarily coated on the substrate may be formed on the upper portion of the silver coating layer, which is referred to as an upper thermosetting resin layer.

Therefore, according to an embodiment of the present invention, a lower thermosetting resin layer is first coated on a substrate constituting a vehicle lamp, a silver coating layer is secondary coated on the lower thermosetting resin layer, and an upper portion of the silver coating layer is applied. A silver coating reflective film is formed by a method in which the upper thermosetting resin layer is tertiary coated, thereby providing a vehicle lamp having a high reflectivity.

On the other hand, it is revealed in advance that the coating method according to an embodiment of the present invention can be used for various purposes in various products, such as a solar reflector or an electromagnetic wave absorber, in addition to the vehicle lamp described above.

After degreasing and drying the surface of the polycarbonate base constituting the vehicle lamp, 30% by weight of an acrylic resin as a resin coating solution, 20% by weight of an epoxy resin, 10% by weight of methyl isobutyl ketone, 20% by weight of xylene as a solvent, butyl acetate To the solution adjusted to a viscosity of about 30-40 cPs by mixing 20% by weight, 0.1% by weight of a silane coupling agent is added and the mixed solution is applied to the surface of the polycarbonate substrate in an air spraying manner to a thickness of about 10 μm.

Then, it is cured at about 100° C. for 1 hour or more. As a device for heat curing, xenon lamps, halogen lamps, high pressure mercury lamps, metal halide lamps, etc. are used as means for irradiating electron beams or ultraviolet rays.

In the activation treatment, a mixed solution diluted with 0.5 mol/l of stannous chloride, 0.5 mol/l of stannous chloride, and 0.5 mol/l of hydrogen peroxide (H ₂ O ₂ ) is applied by air spraying. The mixing ratio of stannous chloride and stannous chloride is preferably 3:1. After application, wash with deionized water.

After the activation treatment with tin chloride solution, activation treatment with silver ions is performed, and the silver ion activation treatment is performed by diluting the silver nitrate solution to about 0.01 mol/L or less on the surface treated with tin chloride or tin chloride. Apply.

The composition of the silver coating solution consists of 3 g of silver nitrate, 25 ml of ammonia (30% solution), 5 g of caustic soda, and 1000 ml of deionized water, and the reducing agent solution is hydrazine sulfate (N ₂ H ₄ + H ₂ SO ₄ → N ₂ H ₆ SO ₄ ) Consists of 2.0 g, citric acid 0.2 g, alcohol 50 ml, and deionized water 100 ml and stored in a separate container.

In the coating method, the silver coating solution and the reducing agent solution are simultaneously sprayed from one nozzle of the air spray gun through separate transport pipes and applied to the lower thermosetting resin layer to form a silver coating layer. After forming the silver coating layer, it is washed with deionized water.

On the upper part of the silver coating layer, the upper thermosetting resin layer is coated with a thickness of about 10 μm, and then dried at about 100° C. for about 1 hour to complete the silver coating reflective film. As a device for heat curing, xenon lamps, halogen lamps, high pressure mercury lamps, metal halide lamps, etc. are used as means for irradiating electron beams or ultraviolet rays.

The same coating method as in Example 1 described above was performed except that 0.3% by weight of the silane coupling agent in the lower resin coating solution was added.

The same coating method as in Example 1 described above was performed except that 0.5% by weight of the silane coupling agent in the lower resin coating solution was added.

The composition of the silver coating solution consists of 2 g of silver nitrate, 25 ml of ammonia (30% solution), 5 g of caustic soda, and 1000 ml of deionized water. And the reducing agent solution is subjected to the same coating method as in Example 1 described above, except that consisting of 2.0 g of hydrazine sulfate, 0.2 g of citric acid, 50 ml of alcohol, and 100 ml of deionized water.

The composition of the silver coating solution consists of 5 g of silver nitrate, 25 ml of ammonia (30% solution), 5 g of caustic soda, and 1000 ml of deionized water. And the reducing agent solution is subjected to the same coating method as in Example 1 described above, except that consisting of 5.0 g of hydrazine sulfate, 0.2 g of citric acid, 50 ml of alcohol, and 100 ml of deionized water.

[Comparative Example 1]

In the tin activation treatment, it is the same as in Example 1 described above except that hydrochloric acid is used instead of hydrogen peroxide.

[Comparative Example 2]

It is the same as Example 1 described above, except that the activation treatment with silver ions was not performed after the activation treatment with tin chloride solution.

[Comparative Example 3]

It is the same as Example 1 described above, except that a silane coupling agent is not used in the resin coating solution composition.

Performance evaluation of coating layer

1) Evaluation of adhesion (A): The surface of the upper thermosetting resin layer was peeled off with a scotch tape on a surface cut across at a distance of approximately 1 mm across the surface, and adhesiveness was evaluated according to the quantity of the peeled part. .

○: not even peeling

△: 1 to 5 peeling

×: 5 or more peeling

2) Salt spray test (B): After spraying a 5% NaCl solution on a polycarbonate substrate coated with a silver-coated reflective film for 500 hours, the condition of the coated surface was evaluated.

○: No corrosion

△: Partial corrosion of corners

×: Partial corrosion of coated surface

Evaluation (A) Evaluation (B) Example 1 ○ ○ Example 2 ○ ○ Example 3 ○ ○ Example 4 ○ ○ Example 5 △ △ Comparative Example 1 × × Comparative Example 2 × × Comparative Example 3 × ×

As shown in [Table 1], it can be seen that according to an embodiment of the present invention, it is possible to obtain a silver coating reflective film having improved adhesion to the silver coating layer and the resin layer and corrosion resistance due to salt water.

The present invention has been described in detail through one embodiment, but this is for specifically describing the present invention, and the method for coating a vehicle lamp according to the present invention is not limited thereto. In addition, the terms "include", "compose", or "have" as described above mean that the corresponding component can be inherent unless specifically stated to the contrary, excluding other components However, it should be interpreted as being able to further include other components, and all terms, including technical or scientific terms, are generally understood by those skilled in the art to which the present invention pertains, unless otherwise defined. It has the same meaning as being.

In addition, the above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains can make various modifications and modifications without departing from the essential characteristics of the present invention. Therefore, the exemplary embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain the scope of the technical spirit of the present invention. The scope of protection of the present invention should be interpreted by the claims below, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the present invention.

Claims (6)

A vehicle lamp coating method for coating a silver-coated reflective film on a surface of a substrate constituting a vehicle lamp,
First coating the lower thermosetting resin layer on the substrate, secondary coating the silver coating layer on the upper portion of the lower thermosetting resin layer, and tertiary coating of the upper thermosetting resin layer on the upper portion of the silver coating layer to provide the silver coating reflective film. Make up,
Before forming the silver coating layer, a mixed solution of dilute tin chloride and tin chloride with 0.1 to 0.5 mol/L and hydrogen peroxide with 0.1 to 0.5 mol/L on the lower thermosetting resin coating layer is applied by air spray, The mixing ratio of tin and stannous chloride is 2~3:1.
The method according to claim 1,
The substrate is a general plastic or waste plastic lamp coating method for a vehicle, characterized in that.
The method according to claim 1,
The lower thermosetting resin layer uses a liquid epoxy resin, an unsaturated polyester resin, a fluorine resin, an acrylic resin, a melamine resin, or a polymer of silicone acrylic resin, or an oligomer, and uses an isocyanate compound or an amine compound as a curing agent. Lamp coating method.
The method according to claim 1,
The lower resin coating liquid for forming the lower thermosetting resin layer is a liquid epoxy resin, an unsaturated polyester resin, a fluorine resin, an acrylic resin, a melamine resin, or a polymer of silicone acrylic resin dissolved in an organic solvent in an organic solvent to air-spray the substrate. Coating, but as a solvent, xylene, nucleic acid, ethyl alcohol, methyl alcohol, butyl acetate or methyl isobutyl ketone, characterized in that the vehicle lamp coating method.
delete The method according to claim 1,
After the activation treatment with the mixed solution, an activation treatment with silver ions is performed, wherein the silver ions are applied to a surface treated with tin chloride or tin chloride by diluting the silver nitrate solution to 0.01 mol/L or less. Vehicle lamp coating method characterized in that.