JP4609738B2 - Highly reflective coating composition and highly reflective coating film - Google Patents

Description

  The present invention relates to a highly reflective coating composition and a highly reflective coating film.

  In general, a liquid crystal display device has a structure in which a light source (so-called backlight) such as a cold cathode tube or a hot cathode tube is provided on the back side of a liquid crystal element, and a reflector is provided on the back side thereof. As described above, the reflection plate provided in the liquid crystal display device is for efficiently using the light from the light source to maintain the brightness of the liquid crystal screen at a high level, and is required to have a high reflection function.

  Conventionally, as a reflection plate provided in a liquid crystal display device, (1) a reflection plate in which a highly reflective film is bonded, (2) a reflection plate made of a highly reflective film itself, (3) white coating Reflected reflectors are known.

  As a film to be provided on the reflector of (1), for example, a film including closed cells that are flat with respect to the film surface direction and having an aperture on at least one surface, and specular gloss and light reflectance are limited. The film and the reflecting plate of (2) have been proposed which are formed of a film or sheet containing fine bubbles with an average bubble size of 50 nm to 50 μm and having a surface having a plurality of angled bent portions ( For example, Patent Documents 1 to 3). However, these films have a problem that the film manufacturing process is complicated and a sticking process is required, so that the cost is high.

  As a white coating applied to the reflector of (3), it has been proposed to apply a paint containing specific white inorganic particles (see, for example, Patent Documents 4 to 8).

  Patent Document 4 discloses a reflective plate for a liquid crystal display in which a white paint containing 100 to 200% by weight of white inorganic particles such as titania, alumina, magnesia, silica, zirconia, and barium sulfate is applied to the surface of an aluminum plate. Has been proposed.

  In Patent Document 5, an undercoat layer containing 150 to 300 parts by weight of a titanium oxide pigment with respect to 100 parts by weight of a resin, and an overcoat layer containing 100 to 250 parts by weight of a titanium oxide pigment with respect to 100 parts by weight of a resin There has been proposed a highly diffuse reflective metal plate formed in the above.

  Patent Document 6 proposes a light reflecting film in which a coating layer containing a light stabilizer is provided on one side of a white film containing bubbles inside, and inorganic fine particles (silica, alumina, oxidation) are provided on the coating layer. Titanium and the like) and / or organic fine particles (silicone compound, crosslinked styrene and the like) are contained in an amount of 5 to 50 parts by weight.

  Patent Document 7 proposes a light reflecting film in which a skin layer containing at least 15% by weight of light diffusing particles is laminated on at least one of the light reflecting layers. Silica particles and hollow particles are used as the light diffusing particles. Titanium oxide particles are exemplified. As a method for forming this skin layer, a method of adding light diffusing particles to a binder resin and coating at least one side of the light reflecting layer is mentioned.

  Patent Document 8 proposes a highly reflective coating film in which a layer in which titanium dioxide is blended with a binder resin is laminated. 2,5-bis [5-t-butylbenzoxazolyl (2)] thiophene is exemplified as the fluorescent substance.

  However, when a coating film is provided by the methods of Patent Documents 4 to 8, there is a problem that a reflectance that can be used as a liquid crystal display reflector cannot be obtained and good display performance cannot be obtained. . Therefore, the reflector (3) has not been put into practical use.

JP 2004-101600 A JP 2006-72347 A JP 2006-215475 A JP 2002-116436 A JP 2002-172735 A JP 2004-126345 A JP 2005-173546 A JP 2006-51686 A

  The present invention has been made in view of the above situation, and an object thereof is to provide a highly reflective coating composition that exhibits a level of reflectance that can be used as a liquid crystal display reflector and that can form a coating film with good display performance. Is.

  The present invention contains titanium oxide and silica in a total amount of 80 to 100% by volume of the total pigment, and the volume ratio of the titanium oxide and the silica is titanium oxide: silica = 80: 20 to 40:60, and the pigment volume. It is a highly reflective coating composition having a concentration (PVC; solid content conversion) of 30 to 70% by volume and an average secondary particle size of the silica of 0.5 to 10 μm. The titanium oxide preferably has an average primary particle size of 0.1 to 1 μm.

  The highly reflective coating composition of the present invention preferably further contains at least one resin selected from the group consisting of polyester resins, melamine resins, acrylic resins, isocyanate resins, fluororesins and epoxy resins.

  The present invention is also a highly reflective coating film obtained by coating the object to be coated with the above highly reflective coating composition. The highly reflective coating film preferably has an expansion ratio of 110 to 200%. The highly reflective coating film preferably has a thickness of 20 to 100 μm.

  Since the highly reflective coating composition of the present invention has the above-described configuration, it can form a coating film having high light reflectance and diffuse reflectance and excellent display performance. In addition to having such characteristics, the highly reflective coating film of the present invention is useful as a material for a liquid crystal display reflector in that the production cost is lower than that of a conventional highly reflective film.

The present invention is described in detail below.
The highly reflective coating composition of the present invention has been completed by finding that a coating film having an extremely high light reflectance can be obtained by adding silica in addition to titanium oxide. In other words, higher whiteness is obtained by increasing whiteness and forming bubbles in the coating film with titanium oxide having high whiteness. Furthermore, the present invention makes it possible to form a coating film having a high reflectance and no coating film defects such as cracks by limiting the volume ratio of titanium oxide and silica.

  In order to form a coating film having such a cell structure, in the present invention, the pigment content in the coating film is increased to limit the average secondary particle diameter of silica. When the pigment content in the coating film is high, it has the property that air is easily embraced in the coating film. For this reason, the highly reflective coating composition of the present invention can form a large number of bubbles in the resulting coating film, thereby increasing the whiteness of the coating film and increasing the reflectance. .

  That is, the highly reflective coating composition of the present invention is such that the total amount of titanium oxide and silica is limited to the above range for the purpose as described above, and the pigment volume concentration of the resulting coating film is limited. Therefore, it is possible to form a coating film having high light reflectance and diffuse reflectance and excellent display performance. In the present specification, “display performance” means performance that is bright as a display display, has no color imbalance, and does not have non-uniform contrast.

  The highly reflective coating composition of the present invention contains titanium oxide and silica as pigments.

  The titanium oxide is not particularly limited as long as it is known as a normal pigment, and may be either a rutile type or an anatase type. Further, a known surface treatment with aluminum oxide, zinc oxide, silica, zircon or the like may be performed. Further, the particle shape is not particularly limited, and any shape such as a spherical shape, a needle shape, and a scale shape can be used.

  The titanium oxide preferably has an average primary particle size of 0.1 to 1 μm in terms of the reflectance described above. If the average primary particle size is less than 0.1 μm, it is difficult to scatter the light, which may reduce the whiteness, which is not preferable. When it exceeds 1 μm, the dispersibility in the paint becomes insufficient, and thus the storage stability of the paint when blended in a large amount may be deteriorated. The average primary particle size has a more preferable lower limit of 0.15 μm and a more preferable upper limit of 0.4 μm. In the present specification, the average primary particle size and the average secondary particle size described later are measured by measuring the particle size distribution by a Coulter counter method using a multisizer three machine (manufactured by Beckman Coulter, Inc.). This is the value obtained.

  The silica is not particularly limited, and examples thereof include hydrophilic silica, hydrophobic silica, and water-dispersible silica. The silica is not particularly limited and known ones can be used, and examples thereof include spherical silica, chain silica, and aluminum-modified silica.

  The spherical silica is not particularly limited, and examples thereof include wet silica such as “Gasyl HP240” and “Gasyl HP260” (both manufactured by Crossfield Corporation), and fumes such as “Aerosil” (manufactured by Nippon Aerosil Co., Ltd.). Dosilica and the like can be mentioned. Examples of the aluminum-modified silica include commercially available silica sols such as “Adelite AT-20A” (manufactured by Asahi Denka Kogyo Co., Ltd.).

  In the present invention, the silica has an average secondary particle size of 0.5 to 10 μm. If the average secondary particle size is less than the above range or exceeds the above range, problems such as cracks may occur, foaming may be insufficient, and the coating film may have a low diffuse reflectance. A preferable lower limit of the average secondary particle size is 1 μm, and a preferable upper limit is 4 μm.

  In addition to the above-mentioned titanium oxide and silica, the highly reflective coating composition of the present invention contains other pigments such as organic beads such as barium sulfate, alumina, calcium carbonate, magnesium carbonate, glass beads, and acrylic beads. You may include in the range which does not impair the effect of invention. However, even in this case, it is necessary to contain titanium oxide and silica in a total amount of 80 to 100% by volume of the total pigment.

  The total amount of titanium oxide and silica is preferably 85% by volume or more, more preferably 90% by volume or more, based on the total pigment. If the above value is less than 80% by volume, sufficient whiteness cannot be obtained, and the reflectance is lowered.

  In the present specification, the above-mentioned total amount and the ratio of each pigment described later are values calculated from the volume of each pigment obtained from the specific gravity and blending amount of each pigment.

  The highly reflective coating composition of the present invention has a pigment volume concentration (PVC) of 30 to 70% by volume. The PVC indicates a volume ratio of the resin after the coating film is formed and the total pigment contained in the paint, and the solvent in the paint volatilizes and the volume of the resin after the curing reaction occurs. By determining the composition of the coating so as to be in the range, it can be within the above range. When the said PVC is less than 30 volume%, the problem that the reflectance of light becomes inadequate arises about the coating film obtained. When the PVC exceeds 70% by volume, there arises a problem that the stability of the paint is lowered or a coating film having sufficient strength cannot be obtained.

  The PVC has a preferred lower limit of 35% by volume, a more preferred lower limit of 40% by volume, a preferred upper limit of 65% by volume, and a more preferred upper limit of 60% by volume.

  In the present specification, the PVC is expressed by the formula PVC = P from the volume (P) of all pigments determined by the specific gravity and blending amount of each pigment and the volume (R) of resin determined by the specific gravity and blending amount of each resin. / (P + R) × 100.

  In the present invention, the volume ratio of the above-mentioned titanium oxide and silica is titanium oxide: silica = 80: 20 to 40:60. In the highly reflective coating composition, if the silica ratio is lower than the above range, defects such as cracks occur during coating film formation, the reflectance becomes insufficient, and the silica ratio is higher than the above range, The stability of the coating film is lowered, and the coating film has low strength and reflectance. The volume ratio is preferably titanium oxide: silica = 70: 30 to 50:50.

  The highly reflective coating composition of the present invention preferably contains a binder resin. The binder resin is not particularly limited, and examples thereof include various resins widely used in the field of thermoplastic resins and thermosetting resins. For example, polyester resins, melamine resins, acrylic resins, isocyanate resins, fluororesins , Epoxy resin, polyamide, polyesteramide, polyvinyl chloride, polyurethane, polycarbonate, polystyrene, polyolefin, and copolymers and mixtures thereof. The binder resin may be a water-based resin or a solvent-based resin.

  The binder resin is preferably at least one resin selected from the group consisting of a polyester resin, a melamine resin, an acrylic resin, an isocyanate resin, a fluororesin, and an epoxy resin, and more preferably a polyester resin.

  The polyester resin preferably has a number average molecular weight of 5000 or more and 35000 or less. The number average molecular weight is more preferably a lower limit of 10,000, and a more preferable upper limit of 30000. In the present specification, the number average molecular weight is a value measured by a gel permeation chromatograph (GPC, manufactured by Shimadzu Corporation).

  The polyester resin preferably has a glass transition temperature of −10 ° C. or higher and 70 ° C. or lower. The glass transition temperature has a more preferable lower limit of −5 ° C., and a more preferable upper limit of 50 ° C. In this specification, the glass transition temperature is a value measured by a differential scanning calorimeter (DSC, manufactured by Seiko Instruments Inc.).

  The highly reflective coating composition of the present invention may further contain a curing agent. The curing agent is not particularly limited, and examples thereof include amino resins such as melamine resins, isocyanate compounds, and blocked polyisocyanate compounds.

  In addition to the components described above, the highly reflective coating composition of the present invention may contain additives generally used in coating materials such as a leveling agent, a pigment dispersant, and an anti-waxing agent, if necessary.

  The highly reflective coating composition of the present invention may be solvent-based or water-based. The organic solvent is not particularly limited, and hydrocarbon solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and isophorone; ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, and the like Examples include ester solvents; alcohol solvents such as methanol and ethanol; ether alcohol solvents such as ethylene glycol monoethyl ether and diethylene glycol monobutyl ether; and the like. The highly reflective coating composition may contain one kind of the above-mentioned solvent, or may contain two or more kinds.

  The method for producing the highly reflective coating composition of the present invention is not particularly limited, and each of the above-described pigments, binder resin, and, if necessary, the above-described additives are used using a roller mill, a paint shaker, a disper, a bead mill, or the like. All methods known to those skilled in the art such as kneading and dispersing can be used.

  In the above production method, it is preferable to prepare the pigment dispersion paste in advance and then mix and disperse the pigment dispersion paste and other components such as a binder resin in order to stably and sufficiently disperse the above-described pigments. .

  A highly reflective coating film obtained by coating the above-described highly reflective coating composition on an object to be coated is also one aspect of the present invention.

  The highly reflective coating film of the present invention is obtained by coating the above-described highly reflective coating composition, and has a high light reflectance because it contains titanium oxide. Furthermore, since the above-mentioned highly reflective coating composition has a high pigment content, it is easy to entrap air when forming a coating film. Therefore, the highly reflective coating film is a foamed coating film containing a large number of bubbles, and from this point, a higher reflectance can be obtained. Since these effects are so excellent that they can be put into practical use, the above highly reflective coating film can be suitably applied to a liquid crystal display reflector. The formation of a highly reflective coating film by such a method is preferable because it is easier to produce than a conventionally used highly reflective film and the production cost is low.

  As described above, the highly reflective coating film of the present invention generally contains bubbles. In the highly reflective coating film, the expansion ratio is preferably 110 to 200%. If the expansion ratio is less than 110%, the diffuse reflectance is low and the display performance may be insufficient. If it exceeds 200%, physical properties such as strength may be inferior. A more preferable lower limit of the expansion ratio is 130%, a further preferable lower limit is 150%, a more preferable upper limit is 180%, and a further preferable upper limit is 170%.

In the present specification, the above expansion ratio is measured by using an electromagnetic film thickness meter (manufactured by Fischer) at 10 arbitrarily selected locations, the actual film thickness (T ¹ ) calculated from the average value, and the coating composition. It is a value obtained as a ratio (T ¹ ) / (T ² ) with a film thickness (T ² ) as a theoretical value calculated from the coating amount per m ^{2 of the} product and the density of the coating film.

  Since the high-reflective coating composition of the present invention described above has a high pigment content as described above, the above-described foaming ratio can be obtained by applying a usual method to form a coating film.

  The highly reflective coating film of the present invention preferably has a film thickness of 20 to 100 μm. If the film thickness is less than 20 μm, a problem may occur in strength and display performance, and if it exceeds 100 μm, a problem may occur in strength. The film thickness has a more preferable lower limit of 30 μm and a more preferable upper limit of 80 μm. In the present invention, the film thickness is measured using an electromagnetic film thickness meter (Fischer).

  Although the said highly reflective coating film is not specifically limited, For example, the process of coating the said highly reflective coating composition on a to-be-coated object, and the process of forming the coating film by hardening | curing the coating material obtained by the said process It can form by the method which consists of.

  The object to be coated is not particularly limited as long as it can be used as a liquid crystal display reflector. Metal plate, film, plastic, glass and the like. The highly reflective coating film may be a film coated on an object to be coated with a film or a coating film as necessary.

  The above-mentioned coating can be performed by a conventionally known method on a precoat metal such as a die coating method, a roll coating method, a curtain flow coater method, a roll curtain method, a spray method, and various curtain coaters. The curing can be appropriately selected according to the composition of the coating composition to be used and the type and size of the object to be coated. For example, the curing is performed at a temperature of 100 to 300 ° C. for 20 to 180 seconds. be able to.

  The precoat metal in which the highly reflective coating film of the present invention is formed on a substrate such as a metal plate can be suitably applied to a liquid crystal display reflector as described above. A liquid crystal display reflector having the above highly reflective coating film is also one aspect of the present invention. The liquid crystal display reflector can form a screen with excellent display performance and high reflectivity by the highly reflective coating film exhibiting the above-mentioned properties.

  The liquid crystal display reflection plate of the present invention is not particularly limited as long as it has the above-described highly reflective coating film, and is provided with a highly reflective coating film on an undercoat layer previously provided on an object to be coated, An overcoating film layer may be further formed on the highly reflective coating film.

  The undercoat coating film can be obtained by applying the undercoat paint composition using a known method.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

<Example 1>
(1) 132 g of titanium oxide (“TIPAQUE CR97” manufactured by Ishihara Sangyo Co., Ltd., average primary particle size 0.25 μm) and 136 g of polyester resin (“Byron GK19CS” manufactured by Toyobo Co., Ltd., Mn = 13000, Tg = 11 ° C.) and solvent ( After mixing 120 g of cyclohexanone manufactured by Sumitomo Chemical Co., Ltd., 600 g of glass beads were added and dispersed in a dispersing machine (“Desktop SG Mill 1500W Model” manufactured by Ohira System Co., Ltd.) to obtain a pigment dispersion paste.

  (2) To 388 g of the obtained pigment paste, 70 g of silica (“Nipseal E200A” manufactured by Tosoh Silica Co., Ltd., average secondary particle size 3 μm), 100 g of polyester resin (“Byron GK19CS” manufactured by Toyobo Co., Ltd.) and melamine resin (Mitsui Cytec) 37 g of "Cymel 712") and 120 g of solvent A (cyclohexanone manufactured by Sumitomo Chemical Co., Ltd.) were kneaded, and then 105 g of solvent B (cyclohexanone manufactured by Sumitomo Chemical Co., Ltd.) was added to obtain a highly reflective coating composition. The resulting highly reflective coating composition was 35% by volume of PVC, 50% by volume of titanium oxide in all pigments, and 50% by volume of silica. In the present specification, the solvent A and the solvent B are the same type of solvent. However, for the sake of clarity, the solvent added first is referred to as “solvent A” and the solvent added later is referred to as “solvent A”. Solvent B ".

<Example 2>
The amount of titanium oxide in the preparation of the pigment paste was changed to 240 g, the amount of the polyester resin was changed to 236 g, the solvent was changed to 200 g, the amount of the pigment paste was changed to 676 g, and the amount of the polyester resin added to the pigment paste A highly reflective coating composition was prepared in the same manner as in Example 1 except that the amount of silica was changed to 0 g, the amount of silica was changed to 85 g, and the amount of solvent A was changed to 130 g.

<Example 3>
The amount of titanium oxide in the preparation of the pigment paste was changed to 586 g, the amount of the polyester resin was changed to 236 g, the solvent was changed to 360 g, the amount of the pigment paste was changed to 1182 g, and the amount of the polyester resin added to the pigment paste A highly reflective coating composition was prepared in the same manner as in Example 1 except that the amount of silica was changed to 0 g, the amount of silica was changed to 77.8 g, and the amount of solvent A was changed to 170 g.

<Example 4>
In the preparation of the pigment paste, the amount of titanium oxide was changed to 446 g, the amount of the polyester resin was changed to 236 g, and the solvent was changed to 360 g. In addition, 160 g of barium sulfate (“Precipitated barium sulfate # 100” manufactured by Sakai Chemical Industry Co., Ltd.) was used. In addition, the amount of pigment paste was changed to 1202 g, the amount of polyester resin added to the pigment paste was changed to 0 g, the amount of silica was changed to 57.8 g, and the amount of solvent A was changed to 170 g. A highly reflective coating composition was prepared in the same manner as in Example 1.

<Comparative Example 1>
At the time of pigment paste preparation, the amount of titanium oxide was changed to 81 g, the amount of polyester resin was changed to 136 g, the solvent was changed to 100 g, the amount of pigment paste was changed to 317 g, and the amount of polyester resin added to the pigment paste A highly reflective coating composition was prepared in the same manner as in Example 1, except that 100 g of silica was changed to 43 g and the amount of solvent A was changed to 60 g.

<Comparative Example 2>
The amount of titanium oxide in the preparation of the pigment paste was changed to 380 g, the amount of the polyester resin was changed to 236 g, the solvent was changed to 200 g, the amount of the pigment paste was changed to 816 g, and the amount of the polyester resin added to the pigment paste A highly reflective coating composition was prepared in the same manner as in Example 1, except that 0 g was changed to 10.6 g of silica and the amount of solvent A was changed to 0 g.

<Comparative Example 3>
At the time of pigment paste preparation, the amount of titanium oxide was changed to 733 g, the amount of polyester resin was changed to 236 g, the solvent was changed to 450 g, the amount of pigment paste was changed to 1419 g, and the amount of polyester resin added to the pigment paste A highly reflective coating composition was prepared in the same manner as in Example 1 except that 0 g was changed to 0 g, the amount of silica was changed to 0 g, and the amount of solvent A was changed to 0 g.

<Comparative example 4>
The amount of titanium oxide in the preparation of the pigment paste was changed to 240 g, the amount of the polyester resin was changed to 236 g, the solvent was changed to 200 g, the amount of the pigment paste was changed to 676 g, and the amount of the polyester resin added to the pigment paste Except that the amount of silica added to the pigment paste was changed to “Gasyl HP395” (Crossfield, average secondary particle size 12 μm). A highly reflective coating composition was prepared in the same manner as in Example 1.

<Comparative Example 5>
The amount of titanium oxide at the time of pigment paste preparation was changed to 1172 g, the amount of polyester resin was changed to 236 g, the solvent was changed to 550 g, the amount of pigment paste was changed to 1958 g, and the amount of polyester resin added to the pigment paste A highly reflective coating composition was prepared in the same manner as in Example 1, except that 0 g was changed to 15.6 g and the amount of solvent A was changed to 450 g.

<Comparative Example 6>
At the time of pigment paste preparation, the amount of titanium oxide was changed to 100 g, the amount of polyester resin was changed to 136 g, the solvent was changed to 100 g, the amount of pigment paste was changed to 336 g, and the amount of polyester resin added to the pigment paste A highly reflective coating composition was prepared in the same manner as in Example 1 except that 100 g of the composition was changed to 159 g of silica and the amount of solvent A was changed to 500 g.

<Comparative Example 7>
The amount of titanium oxide in the preparation of the pigment paste was changed to 386 g, the amount of the polyester resin was changed to 236 g, and the solvent was changed to 360 g. At the time of preparation, 230 g of barium sulfate (“Precipitated barium sulfate # 100” manufactured by Sakai Chemical Industry Co., Ltd.) In addition, the amount of pigment paste was changed to 1212 g, the amount of polyester resin added to the pigment paste was changed to 0 g, the amount of silica was changed to 47.8 g, and the amount of solvent A was changed to 170 g. A highly reflective coating composition was prepared in the same manner as in Example 1.

[Test example]
(1) Preparation of coating film "FLC600 primer" (manufactured by Nippon Fine Coatings Co., Ltd.) was previously applied to a 0.5 mm galvanized steel sheet to a dry film thickness of 20 μm, and an oven (compact test oven manufactured by NK TEC Co., Ltd.) ) Is dried at a baking time of 60 seconds so that the maximum plate temperature is 225 ° C., and any of the coating compositions obtained in each Example and each Comparative Example is dried and has a theoretical film thickness (T ² ) of 35 μm. And dried in a baking time of 100 seconds so that the maximum plate temperature reached 225 ° C. was obtained.

(2) The following evaluation was performed about the obtained coating film.
1. Film thickness Measured using an electromagnetic film thickness meter (Fischer).

2. Volume ratio of each pigment It calculated from the volume of each pigment calculated | required by specific gravity and the compounding quantity of each pigment.

3. PVC
Calculated from the formula PVC = P / (P + R) × 100 from the volume (P) of all pigments determined by the specific gravity and blending amount of each pigment and the volume (R) of the resin determined by the specific gravity and blending amount of each resin. .

4). Foaming ratio Using an electromagnetic film thickness meter (manufactured by Fischer), 10 arbitrarily selected points were measured, the actual film thickness (T ¹ ) calculated from the average value, and the coating amount per m ^{2 of the} coating composition And the ratio (T ¹ ) / (T ² ) with the film thickness (T ² ) as a theoretical value calculated from the density of the coating film.

5. Coating film state When a smooth coating film was obtained, the film was evaluated as x when there was a coating film defect such as ◯ and crack.

6). Diffuse reflectance Using a spectrophotometer UV-3100PC (manufactured by Shimadzu Corporation), the reflectance at 555 nm was measured using barium sulfate as a standard sample.

  The results are shown in Table 1.

  From the above results, it was found that the highly reflective coating composition of each example can provide a coating film having a good coating state and excellent diffuse reflectance.

  Since the highly reflective coating composition of the present invention has the above-described configuration, it can form a coating film having high light reflectance and diffuse reflectance and excellent display performance. In addition to having such characteristics, the highly reflective coating film of the present invention is useful as a material for a liquid crystal display reflector in that the production cost is lower than that of a conventional highly reflective film.

Claims (6)

A coating composition for forming a highly diffuse reflective coating film having an expansion ratio of 110 to 200%,
Contains 80 to 100% by volume of the total pigment of titanium oxide and silica,
The volume ratio of the titanium oxide and the silica is titanium oxide: silica = 80: 20 to 40:60,
The pigment volume concentration (PVC; solid content conversion) is 30 to 70% by volume,
The silica has an average secondary particle size of 0.5 to 10 μm,
A highly diffuse reflective coating composition, wherein the titanium oxide has an average primary particle size of 0.1 to 1 µm. The highly diffuse reflective coating composition according to claim 1, wherein the pigment volume concentration is 40 to 70% by volume. The highly diffuse reflective coating composition according to claim 1, wherein the silica has an average secondary particle size of 0.5 to 4 μm. The highly diffuse reflective coating composition according to claim 1, further comprising at least one resin selected from the group consisting of a polyester resin, a melamine resin, an acrylic resin, an isocyanate resin, a fluororesin, and an epoxy resin. A highly diffuse reflective coating film obtained by coating the object to be coated with the highly diffuse reflective coating composition according to claim 1. The highly diffuse reflective coating film according to claim 5, wherein the film thickness is 20 to 100 μm.