JPH08131939A - Method for improving resistance to chipping of color clear film - Google Patents

Abstract

PURPOSE: To improve effect of resistance to chipping by improving a prior invention regarding the color clear coating technology to be applied on a chromium plating. CONSTITUTION: The surface of a chrome plating 2 is cleaned as shown in the Figure (A), and a protection means 7 for preventing soil is provided, and a transparent primer film 13 of thickness of 10-15μm is formed by a two-part polyester transparent shaping primer 12 as shown in the Figure (B), and a color clear film 15 of thickness of 15-25μm is formed with a two-part reaction type clear coating material 14 color-matched with a transparent pigment 10 as shown in the Figure (C).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention provides a bright color other than chrome to the appearance of a chrome-plated member, and
The present invention relates to a technology for forming a color clear coating film having improved impact peeling resistance (chipping resistance), and has a high practical effect when applied to vehicle exterior parts that are easily subjected to external impact.

[0002]

2. Description of the Related Art For example, an exterior member for a vehicle is often made of a synthetic resin material and plated with chrome. As a usage condition peculiar to vehicle exterior products, there are many occasions in which pebbles, sand grains, etc. come in and collide. Therefore, chipping resistance that resists external impact and does not cause peeling is required. If the thickness of the plating is increased, the chipping resistance will be improved.However, if the thickness of the plating is increased, the cost of the plating process will be more than proportional to the thickness. It is desirable to provide it. Sputtering treatment is known as a technique for improving the chipping resistance, but the sputtered coating is corroded from the portion subjected to the chipping, causing discoloration,
In addition to the drawback that the peeling progresses, there are many steps such as molding → undercoat → drying → sputter treatment → topcoat → drying, and special equipment is required, resulting in high processing cost.

Color clear coating is known as a surface treatment for the chrome-plated surface. This color clear coating is
Although it is a treatment that forms a colored transparent coating and gives a bright color other than chrome, the conventional color clear coating has a low impact strength and a satisfactory effect in improving chipping resistance can be obtained. There wasn't. Even if an attempt is made to improve the chipping resistance of the color clear coating film, the chipping resistance is not improved even if the thickness dimension of the coating film is increased. The reason is,
This is because when the thickness of the coating film becomes thick, cohesive failure occurs at a location where a local impact is applied, resulting in interfacial peeling between the plating layer and the coating film. Further, even when a paint for forming a coating film having high mechanical strength is searched for, it is difficult to put it into practical use because there is nothing that is compatible with the chromium surface.

[0004]

Therefore, the inventor of the present invention
(A) Paint that forms a coating film with high chipping resistance,
(B) Coating conditions that allow the paint to be compatible with the chrome-plated surface, (c) Upper limit of film thickness dimension that does not induce interfacial peeling due to cohesive failure, and (d) limit that can exhibit chipping resistance The lower limit of the film thickness and the above four conditions were comprehensively studied. Since these four properties are interrelated, the combinations are very diverse. For example, when the type of paint in (a) changes, the coating conditions in (b) also change, and the dimensional limits in (c) and (d) also change. No matter how much time I have, even if I try these things indiscriminately from one side to the other, I have to spend a great deal of research money and lose my effort. The present inventor scientifically analyzed the accumulation of many years of empirical knowledge regarding surface treatment, selected paints with high expectations for practical effects, narrowed down the range of trial and error, and efficiently promoted test research. Results, a. Rinse the chrome-plated surface with water, b. Dry the surface of the chrome-plated surface that has been washed with water so that no traces of water droplets remain, and c. Protect the cleanliness of the chrome-plated surface such that the dried chrome-plated surface maintains a 40% dyne / cm wettability; d. Silicon / acrylic 2 on clean chrome plated surface
A clear coating film having a film thickness of 15 to 25 μm is constituted by a liquid reaction type coating material, and a transparent pigment is previously mixed into the above-mentioned silicone / acrylic type two liquid reaction type coating material to form the clear coating film. It was confirmed that the method of applying a color clear coating film was extremely effective. However, the means for protecting the cleanliness of item c in the above means that the chrome-plated surface is not contaminated between the drying of item b and the coating of item d, and the protecting means appears in appearance. It doesn't need to. For example, if the coating is carried out immediately after drying, in this case, "no chance of being soiled" is a protection means. In addition, the condition of drying so as not to leave water drop marks in the item b is an expression of cleanliness in washing and drying. That is, in this case, the water droplet mark is the evaporation residue of the washing water, and the presence of the water droplet mark that can be visually recognized indicates impure clean water or dust in a dry atmosphere. In order for the present invention to achieve the intended purpose, it is necessary that the degree of cleanliness is such that no visually noticeable water droplet marks are produced. The water droplet traces mainly indicate the absence of minute foreign matter, and the wettability described in the item c indicates the degree of chemical contamination, which is, so to speak, invisible to the naked eye such as oil and oxide films. The above method is an invention created by the present inventor and applied for separately by the present applicant (Japanese Patent Application No. 6-211111), and will be hereinafter referred to as an invention of the prior application. 2A and 2B are schematic process diagrams showing one embodiment of the method for forming a color-clear coating film having chipping resistance according to the invention of the prior application, where FIG. 2A is a washing process and FIG. 2B is a drying process. (C) is a protection step,
(D) illustrates the painting process. However, since it is schematically illustrated, the implementation state of the method of the present invention is not necessarily shown realistically. (A) A as shown in the figure
BS (acrylonitrile, butadiene, styrene resin)
A chromium plating 2 is formed on the surface of a base member 1 made of metal. The surface of the chrome plating 2 is washed with pure water 4 ejected from the nozzle 3. Pure water in this case means pure water as the opposite of aqueous solution, not pure water in high-purity chemistry. Further, the water faucet is drawn for the sake of easy understanding at first glance, and is not a realistic drawing of the embodiment. (B) As shown in the figure, the surface of the chrome-plated 2 that has been washed with water is dried with warm air blown from the blower 5. This is also schematically drawn for easy understanding at first glance, and in short, it may be dried in a clean state. As shown in (C), the cleanliness of the surface of the chrome plating 2 is maintained by the protection means 7. It is not always necessary to cover with a cover as shown in the figure, and the entire work space may be a dust-free room. In this way, the wettability of the surface of the chrome plating 2 is maintained at 40 dynes / cm or more. (D) As shown in the figure, the transparent pigment 10 is mixed with the paint resin (varnish) of the silicone / acrylic two-component reactive paint 9 to adjust it to a desired color tone. Coating is performed to form a color clear coating film 11 having a thickness of 15 to 25 μm. This drawing is also schematically drawn for easy understanding at first glance, and painting is not necessarily performed with a spray gun. Since the surface of the chrome plating 2 is kept clean as shown in FIGS.
The acrylic two-component reactive paint 9 has good affinity (chemical adhesion) to the chrome plating 2 and has sufficient chipping resistance because the clear coating film thickness is 15 μm or more. Since the thickness is 25 μm or less, there is no fear of interfacial peeling due to cohesive damage and excellent durability. The silicone / acrylic two-component reactive coating material 9 of this embodiment according to the invention of the prior application is a coating material containing an acrylic resin as a main component and a compound containing an alkoxylated silanol group as a curing agent.

In the above-mentioned prior invention, the cleanliness represented by the items a to c, that is, the trace of water drops which can be visually recognized is not left, and the wettability of 40 dyne / cm is ensured by the silicone.
The acrylic two-component reactive coating material forms a coating film by being compatible with the chrome-plated surface. If the thickness of the coating film is 15 μm or less, the chipping resistance is insufficient, and if it is 25 μm or more, interfacial peeling may occur due to cohesive failure. However, as in the present invention, the film thickness dimension is 15 to 25 μm. In this case, sufficient chipping resistance can be obtained without the risk of interfacial peeling. Moreover, since the silicone-acrylic two-component reactive coating is colorless and transparent, it is necessary to add a desired color tone by mixing it with a transparent pigment (for example, a metallic tint with a bluish tint or a yellowish tone). It is possible to obtain metallic luster, etc.), and it is possible to combine mechanical durability with a design glossy color tone, and increase the commercial value. Moreover, the facility cost and the running cost are lower than, for example, the sputtering process. After completing and applying for the invention of the above-mentioned prior application, the present inventor carries out the practical application test research, and confirms that the above-mentioned prior invention sufficiently achieves the intended purpose under the practical conditions. We pursued further improvement in chipping resistance. The purpose of the present invention is to
Without impairing the advantages of the invention according to the prior application, that is, it is possible to give a bright color tone other than chrome color, without losing the advantage of low cost, further improve the chipping resistance, and also excellent in weather resistance. Another object of the present invention is to provide a method for constructing a color clear coating film.

[0006]

In order to achieve the above-mentioned object (improving the chipping resistance by improving the invention of the prior application), the method according to the present invention comprises: a. Washing the chrome-plated surface with water, b. A step of drying so that no traces of water droplets remain on the surface of the chrome-plated surface that has been washed with water; c. Dry chrome plated surface has a wetness of 40 dyne /
a means for protecting the cleanliness of the chrome-plated surface so as to keep cm; d. Film thickness of 10 to 15 μm on a clean chrome-plated surface using a transparent 2-chip polyester chipping primer
Forming a transparent primer coating film of e. And a step of forming a clear coating film having a film thickness of 10 to 15 μm on the transparent primer coating film by using an acrylic polyol-based or silicon acrylic-based two-component reactive clear coating material. It is characterized in that a transparent pigment is previously mixed into a two-component reactive clear coating material to make the above-mentioned clear coating film a color clear coating film.

[0007]

According to the above means, the silicone / acrylic two-component reactive clear coating film formed in the step (e) is acrylic polyol type or silicon acrylic type,
In addition, since the coating film thickness is 15 μm or more, it exhibits excellent chipping resistance, but since it is layered on the two-component polyester transparent chipping primer, the clear film, the film and the transparent chipping primer are Excellent chipping resistance can be obtained by cooperation. Furthermore, a to c
Since the cleanliness of the chrome-plated surface is ensured by the step (2), the two-component polyester transparent chipping primer exhibits an affinity for the chrome-plated surface and firmly adheres thereto. Further, since the two-component reactive clear coating material is an acrylic polyol type or a silicon acrylic type, the two-component polyester type transparent chipping primer has good adhesion and can be layered without fear of peeling. Since the above-mentioned two-component reactive clear coating allows passage of ultraviolet rays in sunlight, the primer is not susceptible to deterioration by receiving ultraviolet rays. However, in the method of the present invention, since a two-component polyester transparent chipping primer is used, It does not easily deteriorate and has excellent weather resistance. Therefore, no interfacial peeling between the plated surface and the primer layer occurs. Further, since the two-component reactive clear coating material used in the present invention is an acrylic polyol type or a silicone acrylic type, it is possible to form a color clear coating film having a desired color tone by blending a transparent pigment, and to obtain a luster different from that of a chrome color. By coloring and adjusting the design, the product value can be increased.

[0008]

EXAMPLE FIG. 1 is a process chart in one example of the method for improving the chipping resistance of a color clear coating film according to the present invention, in which (A) shows a cleaning treatment process for a chrome-plated surface,
(B) schematically illustrates a primer coating process using a two-component polyester transparent chipping primer paint, and (C) illustrates a color clear coating process using a two-component reactive clear paint containing a transparent pigment. This Figure 1 (A)
2 corresponds to the stage of FIG. 2C, which illustrates the invention of the prior application. That is, the washing step of FIG. 2 (A) and FIG. 2 (B)
After the drying process, the surface of chrome plating 2 gets wet
The state is maintained at 0 dyne / cm or more. The technical meaning represented by the protection means 7 is also the same as in the invention of the above-mentioned prior application. As shown in FIG. 1B, a transparent primer coating film 1 is formed on the surface of the cleaned chrome plating 2 by a two-component polyester transparent chipping primer 12.
3 is deposited. In FIG. 1, the state of painting with the spray gun 8 is schematically shown so that the work content can be understood at a glance, but the state of implementation is not drawn realistically. The thickness of the transparent primer coating film is 10 to 10.
It is controlled to be 15 μm. This is because if it is less than 10 μm, the chipping resistance is not sufficiently improved, and if it is 15 μm or more, the effect commensurate with the cost increase is not expected. In this case, if a one-component olefin-based primer coating film or the like is formed, there is a risk that interfacial peeling will occur due to ultraviolet degradation. Therefore, in the present invention, a two-component polyester system excellent in ultraviolet degradation resistance (weather resistance) is used. Clear clearing primer is used. Further, as shown in FIG. 1C, the transparent pigment 1 is applied to the two-component reactive clear coating material 14.
0 is mixed to obtain a desired color tone, and a color clear coating film 15 having a thickness of 15 to 25 μm is layered on the transparent primer coating film 13 previously formed. The technical meaning of the thickness of the color clear coating film 15 in this case will be described in more detail. The fact that sufficient chipping resistance cannot be obtained when the thickness is less than 15 μm is that the color clear coating in the invention of the prior application is not obtained. It is similar to that described for the membrane 11. The color clear coating film 15 in the method of the present invention does not directly adhere to the chrome plating 2 and the transparent primer coating film 1
Since 3 is interposed, the risk of interfacial peeling due to cohesive failure is not so great even if the thickness exceeds 25 μm. However, if the thickness exceeds 25 μm, it is difficult to form a uniform layer, and although the processing cost increases, there is no merit commensurate with the cost increase. Therefore, the thickness dimension is 15 to 25 μm.
m is appropriate. The method of the present invention is an improvement of the invention of the prior application, in which the chipping resistance is remarkably improved as compared with the invention of the prior application, and the processing cost is increased to the extent commensurate with the quality improvement. Therefore, it is possible and practically prudent to select either the method of the present invention or the method of the prior invention according to the level of quality required for the product.

[0009]

When the present invention is applied, the silicone / acrylic two-component reactive type clear coating film formed in the step (e) is an acrylic polyol type or a silicon acrylic type, and the coating thickness is 15 μm or more. Therefore, it exhibits excellent chipping resistance, but since it is layered on a two-component polyester transparent chipping primer,
An excellent chipping resistance effect can be obtained by the cooperation of the clear, the film and the transparent chipping primer. further,
Since the cleanliness of the chrome-plated surface is ensured by the steps a to c, the two-component polyester transparent chipping primer exhibits an affinity for the chrome-plated surface and firmly adheres thereto. Further, since the two-component reactive clear coating material is an acrylic polyol type or a silicon acrylic type, the two-component polyester type transparent chipping primer has good adhesion and can be layered without fear of peeling. Since the above-mentioned two-component reactive clear coating allows passage of ultraviolet rays in sunlight, the primer is not susceptible to deterioration by receiving ultraviolet rays. However, in the method of the present invention, since a two-component polyester transparent chipping primer is used, It does not easily deteriorate and has excellent weather resistance. Therefore, no interfacial peeling between the plated surface and the primer layer occurs. Further, since the two-component reactive clear coating material used in the present invention is an acrylic polyol type or a silicone acrylic type, it is possible to form a color clear coating film having a desired color tone by blending a transparent pigment, and to obtain a luster different from that of a chrome color. By coloring and adjusting the design, it has an excellent practical effect of increasing the commercial value.

[Brief description of drawings]

FIG. 1 is a process chart in one embodiment of a method for improving chipping resistance of a color clear coating film according to the present invention,
(A) is a chrome-plated surface cleaning process, (B) is a primer coating process using a two-component polyester transparent chipping primer paint, and (C) is a transparent pigment blended 2
A color clear coating process using a liquid-reactive clear coating is illustrated in each schematic illustration.

FIG. 2 is a schematic process drawing showing one embodiment of the method for constructing a color clear coating film having chipping resistance according to the invention of the prior application, where (A) is a washing process and (B) is a drying process. (C) illustrates a protection process, and (D) illustrates a coating process. However, since it is schematically illustrated, the implementation state of the method of the present invention is not necessarily shown realistically.

[Explanation of symbols]

1 ... ABS base (base member made of acrylonitrile / butadiene / styrene resin), 2 ... chrome plating, 3 ... nozzle, 4 ... pure water, 5 ... blower, 6 ... warm air, 7 ... protection means, 8 ... spray gun, 9 ... Silicon / acrylic two-component reactive coating, 10 ... Transparent pigment, 11 ... Color clear coating, 12 ... Two-component polyester transparent chipping primer, 13 ... Transparent primer coating, 14 ... Two-component reactive clear coating, 15 … Color clear coating.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B05D 7/02 7415-4F 7/24 301 U 7415-4F 302 Y 7415-4F

Claims (1)

[Claims] 1. A method for improving the chipping resistance of a color-clear coating film, which gives a bright color other than a chrome-plated color to the appearance of a chrome-plated member to withstand external impacts, comprising: a. Washing the chrome-plated surface with water, b. A step of drying so that no traces of water droplets remain on the surface of the chrome-plated surface that has been washed with water; c. Dry chrome plated surface has a wetness of 40 dyne /
a means for protecting the cleanliness of the chrome-plated surface so as to keep cm; d. Film thickness of 10 to 15 μm on a clean chrome-plated surface using a transparent 2-chip polyester chipping primer
Forming a transparent primer coating film of e. And a step of forming a clear coating film having a film thickness of 10 to 15 μm on the transparent primer coating film with a two-component reactive clear coating material of acrylic polyol type or silicon acrylic type. A method for improving the chipping resistance of a color clear coating film, which comprises mixing a transparent pigment in advance into a two-component reactive clear coating composition to make the above clear coating film a color clear coating film.