JPH01313575A - Coating composition - Google Patents

Abstract

PURPOSE:To make it possible for a coating composition to form a purely white coating film free of a tinge of yellowness, etc., by mixing an optical whitening agent with a coating composition containing titanium white pigment. CONSTITUTION:A coating composition is prepared by using a thermosetting resin and/or a thermoplastic resin such as an alkyd resin and an acrylic resin as a film-forming component and mixing this component with 30-70wt.%, based on the total pigment, titanium white and 0.05-1.0wt.% (in terms of the solid matter) optical whitening agent, for example, Uvitex OB, a product of CIBA- Geigy. When a white mica pigment [desirably, of a mica/TiO2 of 8/24/6 (by weight)] is used as the white pigment, the optical whitening agent is used in an amount of 0.02-0.5wt.% (in terms of the solid matter).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coating composition that can provide a new hue, brightness, or saturation, and has applications, for example, for non-automotive applications. This invention relates to a coating composition used for boards and the like.

[Conventional technology]

BACKGROUND ART Conventionally, various types of coatings have been applied to various industrial products, crafts, architectural structures, etc. Painting determines the final value of the object being painted, such as making the product more luxurious and adding value. There has been a demand for new functions.

Nowadays, with the diversification of individual requirements for the various products on the market, in painting, not only the performance of various coatings to protect the surface of the object to be coated, but also the beauty of the appearance, especially the color. The role of design is becoming increasingly important.

Here, let's take the color white as an example. For example, in the past few years, the color white has become very popular in automobiles, and the demand for white-painted cars is growing at a remarkable rate, and the market is currently flooded with white cars. In general, white pigments added to white paint include titanium white, zinc white, lead white, barium sulfate, lithopone, etc. Among them, titanium white pigment has the highest refractive index among white pigments. Therefore, it is widely used as an excellent pigment because it has the highest hiding power and coloring power among white pigments.

[Problem to be solved by the invention]

However, even though it is simply white, there is a demand for diversification in terms of hue, saturation, and brightness, such as pure white without yellowing, vivid white, and bright white. The limits of paints in general are becoming clearer. For example, if we look at the titanium white pigment mentioned above, which can be said to be a typical white pigment, titanium dioxide, which is a component of titanium white, itself has a slightly yellowish tinge.
The problem remains that there is a limit to the whiteness when used as a paint.

In view of these circumstances, the present invention has developed a paint composition that provides unprecedented hue, brightness, and saturation, instead of the simple colors that have been used for many years, such as a paint composition that can form a pure white paint film without yellowing. The object of the present invention is to provide a paint composition that has the following characteristics.

(Means for Solving the Problems) In order to solve the above problems, the coating composition according to the present invention contains a fluorescent whitening agent.

In addition, in a coating composition containing a titanium white pigment and using a thermosetting resin and/or a thermoplastic resin as a coating film-forming component, the titanium white pigment may be present in an amount of 30 to 70% by weight in pigment weight concentration.
, and a fluorescent whitening agent in a solid content of 0.05 to 1.0% by weight, respectively.

Furthermore, in a coating composition containing a thermosetting resin and/or a thermoplastic resin as a coating film-forming component and a white mica pigment consisting of mica and titanium dioxide, the solid content of an optical brightener is 0.02 to 0.5. % by weight.

[For production]

The optical brightener contained in the paint composition emits blue to purple fluorescence centered at 420 nm, which causes subtle changes in the hue, saturation, and brightness of the paint, allowing new colors to appear. become.

In the inventions according to claims 2 and 3, since the coloring component as a white pigment is titanium dioxide having a large refractive index, the difference in refractive index between the pigment and the growth-based coating film forming component becomes large, resulting in an effective coloring component. Prisms are formed, resulting in a white paint composition with excellent hiding power and tinting power. At the same time, as mentioned above, since the fluorescent whitening agent emits light that is a complementary color to yellow, the yellow tinge originating from titanium dioxide is canceled out, and whitening is performed. Furthermore, in the invention as claimed in claim 3, since a white mica pigment is used, mica causes complex refraction of light, and an iridescent color that changes in various shades depending on the condition of the light rays can be obtained.

〔Example〕

First, the coating composition according to the present invention is applicable to any type of application, usage form, etc., and is not particularly limited. In other words, fluorescent whitening is applied to general paints that use thermosetting, thermoplastic, and photocurable resins as paint film-forming components and, if necessary, inorganic and organic pigments and solvents. It is a coating composition in which an agent is added, and can take any form such as an organic solvent type, an aqueous dispersion type, an aqueous solution type, a high solid type, a powder type, etc., depending on its purpose and method of use. The target is The object to be coated can be selected from all materials such as metal, plastic, wood and paper. Also, optical, electrical,
It may also be a paint that has special functions such as electronic, thermal, mechanical, etc.

In addition, various additives for improving coating film performance may be blended.

Furthermore, considering the properties of the coating film formed, solid,
It includes those exhibiting all kinds of properties such as clear, dark clear, mica base 1 metal base, color base, etc., and they may be used at any stage and in any combination. For example, in the case of topcoating when multiple coatings are performed, the coating compositions containing optical brighteners (FP) according to the present invention may be coated together, or FP and ordinary paint compositions that do not contain optical brighteners may be coated together. Paint composition! (referred to as P) can be arbitrarily combined as follows.

・Solid (FP) ・Solid (FP) and Clear (P) ・Solid (P) and Clear (FP) ・Solid (F
P) and clear (FP), metal base (FP) and clear (P), metal base (P) and clear (FP)
)・Similar to metal base (F P) and clear (FP),・When layering three layers: color base, metal base, clear color base, mica base, and clear,
For each layer, at least one layer contains FP, making it possible to paint in a total of seven ways.

The optical brightener may be included in the coating composition in any form. For example, any form can be selected, such as simply being dispersed in the paint composition, being coated on the surface of the pigment, or being chemically bonded to a resin that serves as a paint film forming component.

The type of optical brightener is also stilbene type.

Benzimidazoles, benzoxazoles.

Coumarin-based, thiophene-based, xanthine-based, naphthalimide-based, etc. are not particularly limited. More specifically,
For example, 2,5-bis(5'-t-butyl-2-benzoxasilyl)thiophene, fluorescein, eosin, aesculin, sodium N-1-4,4'-diaminostilbene-2,2'-disulfonate Examples include. These may be used alone or in combination.

The amount of the optical brightener added is not particularly limited, but for example, when used in clear paint, the solid content is 0.
．． 02-0.5% by weight, 0.05-1.0% by weight when used in combination with the titanium white pigment below, 0.02-0.5% by weight when used in combination with white mica pigment
It is preferable to set them respectively. If it is less than these ranges, the effect of the present invention may not be sufficiently obtained.On the other hand, if it exceeds these ranges, it may cause problems such as poor appearance (occurrence of cracks) due to precipitation of the optical brightener. ,gloss.

There is a tendency for gloss and fluorescent whitening to decrease.

Next, the coating compositions according to the invention according to claims 2 and 3 (hereinafter both will be referred to as "white coating compositions") will be explained.

As the thermosetting/thermoplastic resin serving as the coating film forming component (binder), those obtained by boat fishing can be used without particular limitation. For example, taking thermosetting resins as an example, those that cure (crosslink) with heat, such as polyester resins, alkyd resins, polyurethane resins, acrylic resins, epoxy resins, silicone resins, and their modified products. Common ones include:
These can be used in combination with curing components such as melamine resins, isocyanate resins, epoxy resins, and polyamines. In addition, each of the above-mentioned resins and curing agents may be used one type at a time, or two or more types may be used in combination.

The titanium dioxide in the titanium white pigment and white mica pigment can be either an anatase type or a rutile type crystal type.

The titanium white pigment is used in an amount of 30 to 70% by weight of the entire white paint composition. If it is less than this range, the hiding power will be poor, and if it exceeds this range, the finished gloss will tend to decrease, which is not preferable.

The white mica pigment may be any pigment as long as it contains both mica and titanium dioxide components, and its form, component ratio, etc. are not particularly limited. The mixing ratio of both is
For example, it is preferable that mica/titanium dioxide = 8/2 to 4/6 (wt%); outside this range, there is a risk that water resistance may decrease. As the mica, it is preferable to use a nearly colorless mica belonging to the muscovite series including interference mica.

The amount of the white mica pigment blended is not particularly limited, but it is preferably contained in a pigment weight concentration of about 15% by weight or less. This is because if it is contained in too large a quantity, it may cause shine and poor water resistance.

In addition to the above-mentioned coating film components, it is preferable to add an arbitrary solvent or diluent to these white coating compositions as necessary from the viewpoint of workability, etc., to adjust the viscosity. This solvent is a component that does not remain in the paint film, but in the white paint composition, it constitutes a uniform color vehicle together with the thermosetting/thermoplastic resin that is the binder, and the binder etc. Depending on the type of paint, it is preferable to select one that dissolves the resin and others, or one that can be diluted to make it easier to apply without causing separation. −
Examples are benzene, toluene.

Aromatic hydrocarbons such as xylene, hexane, heptane,
Organic solvents include aliphatic hydrocarbons such as octane, alcohols such as methanol and ethanol, esters such as acetate, ethers such as cellosolve, and chlorine-containing compounds such as trichloroethylene and dichlorobenzene. These can be used alone or in combination. Further, a co-solvent may be used in combination to further enhance the dissolving power.

Furthermore, various additives that can be added include, for example, desiccants (dryers), plasticizers, thickeners, ultraviolet absorbers, stabilizers, antisettling agents, antifoaming agents, leveling agents, two-body pigments, etc. All of them can be used in general.

A solution of the white paint composition consisting of the above components is prepared, for example, as follows. First, a titanium white pigment or a white mica pigment is uniformly dispersed in a thermosetting resin and/or a thermoplastic resin in advance, and a solvent and other resins are appropriately added thereto to adjust the viscosity. On the other hand, the optical brightener is uniformly dissolved in a suitable solvent, and finally, the pigment-containing resin solution and the optical brightener solution are mixed and stirred to obtain a white paint composition solution. In addition, examples of solvents for optical brighteners include:
The same solvent as the solvent for the pigment-containing resin solution can be used, such as aromatic xylene, but the solvent is not limited thereto.

The usage form of the obtained white paint composition solution is not particularly limited, but among them, for example, one containing a titanium white pigment can be used as a top coat (top coat) in the case of multiple coatings, or Those that are used as base paints when combined with clear paints and contain white mica pigments are suitable for use as intermediate mica base paints in three-coat mica coatings. This 3-coat mica paint is applied on top of the color base paint.
This is a painting method that involves layering mica-based paint and then clear paint. A preferred example of coating using the above-mentioned double-sided paint composition solution will be described below.

First, as a pretreatment prior to painting, metal objects such as iron plates and steel plates are subjected to chemical conversion treatment in the usual manner using zinc phosphate, iron phosphate, etc. to remove any particles that adhere to the surface. Prepare the substrate by removing rust, oil, dirt, etc. after that,
In order to improve adhesion, corrosion resistance, etc., an undercoat layer is formed by applying an undercoat using an electrodeposition paint or the like. The coating film thickness is not particularly limited, but for example, the dry film thickness is 15 to
Approximately 20n is appropriate. Furthermore, it is advisable to perform pretreatment such as degreasing, polishing, and acid treatment on nonmetallic objects such as plastics.

Although the process up to this point is common, the case where the above-mentioned white paint composition is used as a top coat will be described below. In this case, an intermediate coating is applied as necessary to form an intermediate coating layer having a dry film thickness of about 35 to 40 μm, for example. This intermediate coating is performed for the purpose of preventing topcoat paint from being sucked in, improving durability, and smoothing the coated surface, and general intermediate coating paints can be used. Then, to finish, apply this white paint composition,
After that, it is baked and cured to create a white coating.

The thickness of this top coat is also not particularly limited, but it is appropriate that a dry film thickness of about 35 to 40 μm can be obtained.

Next, the case where the above white paint composition is used as a mica base paint in the above three-coat mica coating will be described. First, on the object to be coated on which the undercoat layer has been formed,
Form a coating with any white color base paint. The type of color base paint and the coating thickness are not particularly limited, but for example, a thermosetting type containing a thermosetting resin as a coating film forming component may be used to form a coating film with a dry film thickness of about 35 to 40μ. It is appropriate to form a Then, a white paint composition as a white mica-based paint is applied, for example, so that the film thickness after drying is about 15 to 20 u. After that, this white mica base paint is baked and cured, but before that, a wet-on-wet finish clear paint is applied, for example 35~
It is also useful to apply the coating to such an extent that a dry film thickness of 40 μm is obtained, and then bake both layers at once to remove the solvent and cure. Note that as the clear paint, ordinary ones such as those containing acrylic resin/melamine resin as the main coating film-forming components can be used, and there are no particular limitations.

There are no particular limitations on the coating method for each of the coatings described above. In other words, spray painting using a spray gun, flow coating using a curtain flow coater, etc.
flow coating), dipping coating, electrodeposition coating, electrostatic coating,
Regarding electrodeposition coating, which is performed by any method such as brush or roller coating, and is applied as an undercoat, for example, the electric charge of the electrodeposition paint may be either cationic or anionic. Also, after the intermediate painting is done, #60
Hydraulic hardening using No. 0 hydraulic paper may be performed to improve the smoothness of each coating surface and to obtain good coating film adhesion. Dry and bake.

The curing conditions are not particularly limited, and it is preferable to set the temperature for 1 hour, etc. as appropriate depending on the thermosetting resin used, the type of solvent, or the object to be coated.

Next, more detailed examples and comparative examples of the present invention will be described.

First, examples and comparative examples of white paint compositions containing titanium white pigments and used as top coats will be described.

Examples 1 to 4 - ■ Pretreatment The object to be coated was a steel plate (length 90 x width 200 x thickness 0.8 m).
) was prepared and subjected to chemical conversion treatment using a zinc phosphate metal surface treatment agent (Granodine 5o5000 manufactured by Nippon Paint ■).

■ Kouritate cationic electrodeposition paint (Pa'7-Toseop U manufactured by Nippon Paint ■)
-30) to form a coating film with a dry thickness of 20 nm.

■ Freshly applied melamine resin baking paint (Olga P-2 manufactured by Nippon Paint ■)
Spray painting was performed using one color (gray) under the following conditions.

Spray gun: REA (manufactured by Rands) Nozzle cap #6 Coating viscosity = 25 seconds / #4 Ford cup / 20℃ Discharge rate: 400 centimeters / minute After that, baking hardening was performed at 140℃ / 20 minutes to obtain a dry film thickness of 35p1. A coating film was obtained.

■ 58.3 parts by weight of alkyd resin (Fthalkyd F133-60 manufactured by Hitachi Chemical ■) as the top coating thermosetting resin, and 25.0 parts of melamine resin (Super Beckamin G32l-60 manufactured by Dainippon Ink and Chemicals ■) as the curing agent. Parts by weight, 50.0 parts by weight of titanium dioxide (Thioxide RCR-3 manufactured by BTP, UK) as a white pigment, and 50.0 parts by weight of xylene as a solvent were used to prepare a homogeneous solution iii. On the other hand, as an optical brightener, Uvitex 0B (Uv1tex) manufactured by Ciba Geigy, Japan
A 2% by weight xylene solution of this was prepared using OB) and mixed with the above-mentioned carbohydrate-containing resin solution in the proportions shown in Table 1.

Using the obtained white paint composition solution, a coating film with a dry film thickness of 40 μm was obtained in the same manner as the above intermediate coating.

- Comparative Example 1 - A coating film was formed in the same manner as in the above Example, except that in the top coating of (1) above, a solution of a white paint composition containing no fluorescent brightener was prepared and used.

The obtained coating films of Examples and Comparative Examples were evaluated on the following items.

(al) Hunter (f
The <Lab value was calculated based on the color difference formula of E. Lunter.

(b) Visual Color Judgment Five panelists visually evaluated the degree of whiteness.

(C) Glossiness Five panelists visually evaluated the glossiness.

(dl Accelerated weather resistance QUV 200H test (60° x 4 hours irradiation - '6
A cycle test (0' x 4 hours non-irradiation; total 200 hours) was conducted, and the state of deterioration of the coating film was evaluated based on the color change after the test.

(e) Gloss 60 degree specular gloss was measured using a gloss meter manufactured by Murakami Color Research Institute.

The above results are also shown in Table 1. In addition, in the table, ○ means acceptable, × means not acceptable, and the panel evaluation is 5.
Shows the average person.

As shown in Table 1, the white paint compositions of Examples containing fluorescent brighteners provided coating films that were lustrous, glossy, weather resistant, and pure white without yellowing. In addition, Example 4
In this case, since an amount of the optical brightener is used in an amount exceeding the appropriate range in the invention as claimed in claim 2, while a high degree of whiteness is achieved, glossiness and luster are reduced.

Next, Examples and Comparative Examples of white paint compositions containing white mica pigments and used as mica-based paints will be described.

Examples 5 to 8- ■ Pretreatment ■　Ko Niritate All were conducted in the same manner as in the above examples.

■ Car base ``''' Melamine resin baking paint (Olga P-2 manufactured by Nippon Paint ■
, gray) in the same manner as the intermediate coating in the above example to form a coating film with a dry film thickness of 40 μm.

■ Mica base No. 1 158.3 parts by weight of acrylic resin (Alumatenx NT-448-0 manufactured by Mitsui Toatsu Chemical @) as a thermosetting resin, melamine resin (Dainippon Ink & Chemicals @) as a curing agent
Super Hekkami 7G821-60) 31.7 parts by weight, product name Pearl Brace S as white mica pigment
A uniform solution was prepared using 5.0 parts by weight of ME90-9 (manufactured by Nihon Koken Kogyo@) and 20.0 parts by weight of toluene as a solvent. On the other hand, as an optical brightener, Nippon Ciba Geigy G11l (trade name: Uvitesox OB)
(Uvitex OB) and 2% by weight of this
A xylene solution was prepared and mixed with the above pigmented resin solution in the proportions shown in Table 2.

Using the obtained white paint composition solution, spray painting was performed under the following conditions.

Spray gun: REA (Lands'!A) Nozzle cap floor 6 Painting viscosity: 13 seconds/#4 Ford cup/20℃ Discharge amount: 350d/separation W-: Approximately 15n ■ 1 year'' mica above On top of the base paint layer, a thermosetting acrylic resin clear paint (Super Rack 0-28L manufactured by Nippon Paint ■) was hand-sprayed wet-on-wet to a dry film thickness of 45μ, and then 140℃/20 The desired coating film was obtained by baking and curing for a few minutes.

Comparative Example 2 - Coating was carried out in the same manner as in Examples 5 to 8 above, except that a solution of a white paint composition containing no optical brightener was prepared and used as the mica-based paint of (1) above. A film was formed.

Examples 9 to 12- ■ Pretreatment ■　Konuridate All were conducted in the same manner as in the above examples.

■ Car base S's melamine resin baking paint (Nippon Paint side layer Olga P-2
, White) to form a coating film with a dry film thickness of 40 μm in the same manner as in Examples 5 to 8 above.

■ 80.0 parts by weight of acrylic resin (Almatex NT-448-0 manufactured by Mitsui Toatsu Chemical @) as a thermosetting resin of mica base;
Melamine resin as a curing agent (Dainippon Ink Chemical Industry 01)
Super Betsucomin G32l-60) 16.7 parts by weight, trade name Thioxide RC as white mica pigment
Using 50.0 parts by weight of R-3 (manufactured by Nihon Koken Kogyo@) and 50.0 parts by weight of toluene as a solvent, a uniform solution consisting of these was prepared. On the other hand, as an optical brightener, Nippon Ciba Geigy (trade name Uvitesox OB (14))
A 2% by weight xylene solution of this was prepared using Ilvitex OR) and mixed with the above pigmented resin solution in the proportions shown in Table 3.

Using the obtained white paint composition solution, the above Examples 5 to 8
A coating film was formed by spray painting in the same manner as above.

(2) A clear coating film was formed on the mica base coating layer in the same manner as in Examples 5 to 8 above.

- Comparative Example 3 - Coating was carried out in the same manner as in Examples 9 to 12 above, except that a solution of a white paint composition containing no fluorescent brightener was prepared and used as the mica-based paint in (1) above. A film was formed.

The obtained coating films of Examples and Comparative Examples were evaluated for color difference, visual color judgment, glossiness, accelerated weather resistance, and gloss in the same manner as above.

The above results are shown in Tables 2 and 3 (evaluation etc. in the tables are the same as in Table 1).

As shown in Tables 2 and 3, the white paint compositions of the Examples containing optical brighteners produced coatings that were weather resistant and glossy, and exhibited a pure white color without yellowing. Ta.

In addition, in Example 12, since the amount of optical brightener far exceeding the appropriate range in the invention as claimed in claim 3 is used, while a high degree of whiteness is achieved, glossiness and The gloss is reduced.

〔Effect of the invention〕

Since the coating composition according to the present invention contains a fluorescent whitening agent, it is possible to achieve a color with novel hue, saturation, and brightness that has never been seen before, and the designability associated with the color can be achieved. It can greatly contribute to the improvement of

Furthermore, when this is applied to a white paint composition, it becomes possible to form a white paint film exhibiting a pure white color without yellowing, which far exceeds the limitations of conventional titanium dioxide.

Agent: Patent Attorney Takehiko Matsumoto

Claims (1)

[Claims] 1. A coating composition containing an optical brightener. 2. A coating composition containing a thermosetting resin and/or a thermoplastic resin as a coating film-forming component and containing a titanium white pigment,
The titanium white pigment has a pigment weight concentration of 30 to 70% by weight,
The coating composition according to claim 1, wherein the optical brightener is contained in an amount of 0.05 to 1.0% by weight in terms of solid content. 3 A coating composition containing a thermosetting resin and/or a thermoplastic resin as a coating film-forming component and a white mica pigment consisting of mica and titanium dioxide, the fluorescent whitening agent having a solid content of 0.0
The coating composition according to claim 1, containing 2 to 0.5% by weight.