JP2005097610A - Paint composition with white pearl gloss and its coating film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paint composition with white pearl gloss. <P>SOLUTION: This white paint composition with pearl gloss comprises a solid content and a film-forming material. The solid content comprises at least 90% w/w of a mica, 4-7% w/w of TiO<SB>2</SB>and 0.2-3.0% w/w of a particulate metallic aluminum. The relatively narrow combination of the three solid materials in the defined ratios provides a highly desirable white pearl gloss finish at most advantageously relatively thin film thickness. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to white pearlescent paints, lacquers and primers; their use in an improved process for creating white “pearly” finishes on painted or lacquered surfaces; and The present invention relates to a substrate, particularly a vehicle body, obtained by the above process together with paint.

  In the automotive industry, a pearly white finish has been found for passenger cars and trucks because it has proved more popular with buyers than a flat white finish. The object is a desirable and highly appreciated finished color.

  Conventionally, in order to create a pearly white finish on a vehicle, a three-step coating process is required after the exposed metal portion is primed with one or more primer coatings. To create a pearly white finish, usually apply a base coat of white paint and then contain mica, which is typically uncolored and instead provides a “pearly” finish A pearlescent material coating containing particles of a high refractive index material, and finally a clear coating to seal the underlying layer. Each coating layer must be applied individually and an appropriate drying time and, if necessary, a baking time must be provided before each subsequent layer application. As a result, the production of pearlescent finishes is labor intensive and time consuming.

When coating two different types of paint films on a substrate, it is necessary to provide a drying time longer than that required between multiple coatings of the same type of paint. Drying time is required to solidify each of the paint subbing, nacreous and clear coatings in order to promote the proper solidification of the triple paint finish. Longer drying times are achieved by giving more time to the painted vehicles remaining in the assembly line. In order to provide longer drying times during paint application, it is inappropriate to simply pass the assembly line more slowly through the painting department of an automobile assembly plant. Rather, the entire assembly line must be lengthened to provide additional travel time during which paint drying can occur. To make the assembly line even longer, longer physical factory space is required to run through the assembly line. In a manufacturing plant where the physical space is of tremendous value, it would be impossible to make the assembly line longer to make more time while applying multiple paint coatings. Thus, it may not be possible to manufacture and provide certain types of paint finish vehicles in a somewhat smaller manufacturing plant.

  Patent Document 1 by Jeff et al. Discloses a two-layer coating film and a three-layer coating film finished product for automobiles, and a production process thereof. According to this, an opaque light-interfering pigment is used for top coating or intermediate coating To achieve polychromaticity. The entire material is incorporated herein by reference. The process taught by Jeff involves the use of a two-layer coating, where the first layer contains an opaque white, black or colored pigment to achieve overall hiding, while the second layer is an interference pigment. Yes, do not hide the first layer. In order to complete the finished product, a clear topcoat is still applied on the colored coating. The opaque interference pigment particles taught are multilayer particles, the opaque layer being painted with a transparent dielectric layer, which in turn is painted with a translucent layer. The result of the process gives a pleochroic paint effect, which would be a relatively complex and expensive painting process to apply.

  Sada et al., Patent Document 2, includes a colored base, a first coating layer disposed on the colored base, the first coating layer containing a plurality of transparent gloss bodies, and each gloss body is refracted. A coating film structure comprising an alternating laminate of at least two polymers having different rates, and controlling interference light caused by transmitted light different from reflected interference light and interference light produced from the alternating laminate; Disclosure. The entire material is incorporated herein by reference.

  U.S. Patent No. 5,677,096 to Panush discloses a transparent topcoat composition containing iron oxide surrounded by mica particles with a low pigment to binder ratio. The entire material is incorporated herein by reference. The Panush teachings are particularly directed to the production of colored finishes with depth, transparency and chromaticity. The patent states that iron oxide pigments surrounded by mica are pearlescent and inherently have a concealing ability, but they are said to be additive colors. The desired resulting color is stated not to be obtained with metals such as aluminum, but rather with conventional pearlescent, natural or synthetic pigments. These so-called “colorless and opaque” pigments reduce the value of true colored pigments and result in gray, cloudy, low chromatic colors. Focusing on colored finishes, this patent lacks recognition and teaching of the value of aluminum as a pigment and masking material in pearlescent white finishes.

  U.S. Patent No. 5,677,096 to Panush discloses a milky white effect on a substrate using a multiple coating system, in which a colored primer is applied to the surface, followed by a transparent base coating and then a clear coating. . The entire material is incorporated herein by reference. The concealing quality of this transparent base coating film is poor and the light transmittance is likely to be relatively high. In order to compensate for this property of the base coating, a primer that effectively masks black and white will be needed, and further measures to protect against ultraviolet light will be needed. Otherwise, there can be significant degradation of the electrodeposition coating through the transparent base coating. In addition, a clear base coat will not hide the defects in the primer coat, so the use of a clear base coat requires that the primer coat must be carefully applied and polished thoroughly .

  In the case of conventional titanium dioxide white paint, the amount of titanium dioxide pigment in the paint medium needs to be very large in order to achieve adequate hiding power at reasonable film thicknesses, typically 30-50 μm There is. Such a formulation of paint has little ability to retain any further solid particles and therefore there is little room for adding a pearlizing material such as mica particles to the paint mixture.

  It is known that even when mica is added to a conventional white titanium dioxide paint, the appearance of the white paint does not change. Conventional titanium dioxide-based white paints have a “flat” white appearance despite the titanium dioxide content exceeding 90% w / w of pigment solids and the presence of pearlescent materials.

  Solvent-based paints can hold 40-60% w / w pigment, while water-based paints and primers that do not disperse the pigment in the same way have a lower pigment loading, for example 20-35% w / w. The range of w. In any case, in a conventional white paint, 90% of the pigment must be a white pigment, typically titanium dioxide. Thus, the mica flakes are dragged into the large amount of titanium dioxide pigment needed to create a conventional white paint and the pearlescent appearance of mica is invisible.

  In order to create a traditional white paint pearlescent finish, a white titanium dioxide paint is allowed to solidify in-situ to prevent the “sinking” of the pearlescent material, followed by a mica nacreous coating or other pearls. It was necessary to apply a glossing material. This is because the conventional mica nacreous coating does not have its own hiding power. For the concealment properties of the finished product, a colored base coating is required to cover the sand marks etc. on the article and create the actual color of the painted article. Nacreous coatings only impart a glittering property that transforms a “flat” finish into a “pearly” finish. Titanium dioxide white base and nacreous coatings are two different types of paint, so each coating must be solidified before it can be applied to the surface with other materials. . If flash time is not allowed between the application of the colored base paint and the nacreous paint, striking occurs between the paint films. Paint striking is a painting flow, which occurs when the dye or pigment of the previous paint layer dissolves and penetrates into the solvent of the newly applied material, and changes the finished color of the newly applied material. This is due to the application of two different types of paint coatings without a sufficiently long flash time between the two coatings. The application of a separate mica pearlescent coating necessitates a separate application step that requires sufficient adaptation of the automobile production line, thus substantially increasing the painting cost of each vehicle produced. Cause.

  “Hiding power” is an important quantitative factor in determining the composition of the paint. The hiding power can be defined quantitatively as the property of paint that can completely hide any substrate when sprayed with paint. In general, within the paint industry, the reflectance value when applying paint over a black background is 0.98, the reflectance value when coating with the same thickness over a white background. It is accepted that sometimes complete concealment is achieved. Thus, the hiding power is the paint thickness required to reduce the contrast ratio of the background and the contrast difference to 0.02. The standard numerical value 0.02 is based on the Weber-Fechner contrast law, which indicates that a difference of less than 2% (0.02) cannot be determined by the human eye under moderate lighting conditions.

  The hiding power is produced by the light absorption properties of the pigment particles in the paint film applied to the painted surface. If much light emerges from the top surface of the paint film and the substrate is not cloudy, the paint film is not sufficiently concealed. Most pigments are crystalline in nature. In particular, white pigments tend to scatter light strongly when dispersed in a paint medium. If a single crystal of white pigment could be grown to a sufficient size, it would be a bright transparent glassy crystal. This light scattering property causes a large amount of light to emerge from the surface of the paint film, resulting in a corresponding insufficient hiding power.

  Titanium dioxide is the most common white pigment used in paint. Unfortunately, the hiding power of this pigment is relatively poor. In order to maintain the white color, it is possible to improve the hiding properties by the presence of non-pigmented pigments of course having a greater hiding power. Thus, conventional white base coatings are full of titanium dioxide pigments. Thus, to achieve a white paint color with black and white hiding properties below 35 μm, the paint must contain at least 90% w / w titanium dioxide. This is approaching the maximum pigment content in paint formulations so that the paint can still flow and can be effectively sprayed onto the surface. In contrast, other paint colorants containing pigments with more effective hiding power may contain approximately 5% w / w pigment.

U.S. Patent No. 6,057,031 discloses the use of pigments, pigment formulations, paint formulations and coating surfaces, particularly on car bodies, to provide white and colored pearlescent finishes. One aspect described is, the solids content of the following ranges, namely 0.1% to 15% of _TiO 2, 10 to 99 percent of mica, 0.1% to 20% of aluminum and 0 to 5% of coloring pigments Have a prescription.

  U.S. Patent No. 6,099,056 describes a paint composition useful for providing a white pearlescent finish to a substrate, but we surprisingly find that prior art two- and three-layer coatings are used. We have found a very narrow range of white paint formulations that provide a very high quality pearlescent finish with a reduced film thickness in favor of the white pearl finish of the film.

  Thus, to date, significant progress has been made to provide an improved method for supplying white pearlescent paint finishes and compositions, but the appearance of white pearlescent finishes. There is a need for better paint compositions because of improved and cost effective application methods.

US Pat. No. 5,871,827 US Patent No. 6,350,509 US Patent No. 4,499,143 US Patent No. 4,615,940 International application number PCT / CA02 / 01810

  Surprisingly, we have developed a paint composition containing solids containing components in relatively specific proportions as a mixture of film-forming materials, and optionally additives, etc. It has been found that a greatly improved white pearlescent finish is obtained.

  We are surprised by the relatively small amount of white pigment, i.e. titanium dioxide, a relatively very small amount of particulate metallic aluminum, and a solid content containing a relatively very large amount of pearlized mica and a suitable film-forming agent. In particular, it has been found that a very attractive white nacreous finish can be obtained on a substrate with a relatively thin film thickness.

  It is an object of the present invention to provide a white pearlescent paint composition for use on a painted substrate to obtain an improved white pearlescent paint finish.

  A further object is to provide an improved method for obtaining the finished product on the substrate using the white pearlescent paint composition.

  Another object is to provide a method for making the paint composition.

  Another further object is to provide a substrate, particularly a vehicle body surface, coated with the paint composition that provides the white pearlescent finish.

Accordingly, in one aspect, the present invention includes a solid content and a film-forming material, wherein the solid content is at least 90% w / w mica, 4-7% w / w TiO ₂ and 0.2-3. A nacreous white paint composition comprising 0% w / w of particulate metallic aluminum is provided.

Most preferably, the solid content comprises 94.0 ± 1% w / w mica, 5.0 ± 1% w / w TiO ₂ and 0.5 ± 0.3% w / w aluminum.

  The most preferred embodiment is shown in Table 1. Numerical values are given in% w / w.

  Particularly preferred embodiments are shown in Table 2. The relative values are shown in Table 1.

  We have found that the range and absolute amounts of metallic aluminum components defined by the present invention provide a much more useful artistic sparkling effect and support paint flow viscosity controllability. The aluminum particles may be relatively large or coarse particles having a thickness of 1-2 μm and a diameter of 100-200 μm. Coarse aluminum is available from Delta Colors Inc. And / or Silverline Mfg. Co. , Inc. Can be purchased from The metallic aluminum used in the paint composition is generally sold as “aluminum paste-leaf” or “aluminum paste-non-leaf” in a paste form according to a specific particle size distribution. The aluminum particles may be particles having a thickness of 0.1 to 1 μm and a diameter of 0.1 to 100 μm. These particles can be produced, for example, by “Delta colors Inc.” and / or Silverline Mfg. Co. , Inc. Pigment that can be purchased from the factory and processed as-provided or milled or otherwise processed to reduce the size or size range profile to accommodate the application.

  The content of mica compound is thus at least 90% w / w solids, most preferably about 94.0 ± 1% w / w.

  One preferred pearlized mica compound is known under the trademark XIRALLIC® T60-20 SW Sunbeam Gold, and has a particle size of 5-30 μm.

  Other preferred flaky mica can be successfully used alone or in combination with the XIRALLIC® product. The ratio of different flaky mica can be varied depending on the desired pigment properties and the tolerance for increased manufacturing costs associated with increasing the usage ratio of the preferred XIRALLIC® product shape.

  Other pearlized mica materials include naturally derived metal oxides such as alumina or mica plates coated with high refractive index metal oxides such as titanium dioxide or iron oxide.

  The film-forming material used in the composition of the present invention can be suitably selected from those commonly used in solvent or water-based paint and lacquer formulations known in the art. Preferably, the film forming material is selected from acrylic, urethane, polyester, or melamine formaldehyde resin-based materials. Preferred acrylic resins are acrylamide, acrylonitrile, methyl acrylate and ethylhexyl acrylate.

  A preferred composition is about 7-8% acrylic, about 1% urethane, about 6% polyester and about 5% melamine, when applied to a substrate, based on w / w for the total paint composition. Contains formaldehyde resin.

  The paint composition of the present invention may optionally contain one or more additives selected from UV protection agents, spreading agents, polymerization catalysts, rheology additives and the like.

For simplicity and clarity, the term “solids” herein refers to solids, ie TiO ₂ , mica and aluminum. This does not include any proprietary organic resins or solids that will be film forming materials, or solid additives as described above, used in the paint composition or the cured paint.

  In another form, the present invention provides a nacre on a substrate comprising applying a nacreous white paint composition as defined above onto the substrate and curing the composition onto the substrate. A method for producing a white finish is provided.

  The substrate can be any desired, suitable surface of the object or article, but most preferably the object is a car, truck or similar object.

  Thus, in another form, the present invention provides the above substrate, which is coated with the nacreous white finish defined above by the process defined above.

  The pearly luster formulations of the present invention surprisingly are in a range where the coating can be used to function in the paint process of an automobile in a manner equivalent to a paint layer, a clear non-pearlized coating layer. For example, it is most effective for concealment and ultraviolet shielding. Because of this functional advantage of the formulation according to certain embodiments of the present invention, the use of a 2-coat painting system rather than a 3-coat painting system can be used to obtain a colored pearlized automotive paint finish. forgiven.

  In one embodiment, the paint composition as defined above can be applied as a base coating to a thickness of approximately 18-25 μm and solidified or cured by ambient rapid dewatering and / or baking in an oven. . Then, preferably, a clear coating film is applied thereon so that the total film thickness is about 35 to 45 μm.

  In yet another embodiment, the present invention provides the steps of applying to a body a base coating of at least one pearlescent white paint formulation of the present invention, solidifying the base coating, clearing the base coating. A method is provided for producing a nacreous white finish on an object comprising applying a coating and solidifying the clear coating.

  The base coating as defined above can be used alone as a final finish on a substrate, without a clear coating finish, overlying a primer or electrolytic coating.

  Such a very small amount of shielding component and such a very low amount of white pigment in such a large amount of pearlizing material will make such an attractive pearly white paint finish. Being able to offer is a great surprise.

  For a better understanding of the present invention, a preferred embodiment will now be described, by way of example only, with reference to the drawings.

  The paint composition previously shown in Table 2 was prepared from the film former and solids as an aqueous formulation in the amount shown in Table 1 based on% w / w according to standard procedures known in the art. .

  The above-described paint composition of the present invention is applied onto a white primer coating film on the surface simulating an automobile body, cured, and then painted with a conventional clear coating film, so-called “2-coating film”. A pearly white finish was obtained. For comparison, prior art 2-coat and 3-coat nacreous white finishes were prepared and compared in FIG. Here, lines A and B are prior art 2-coating white pearl compositions, line C is prior art 3-coating pearl composition, and line D is the 2-coating white pearl of the present invention. The composition is shown. Each of the above-mentioned paint products has the clear coating composition of the uppermost layer.

  FIG. 1 shows the thickness of a cured paint film that is cost effective and provides a significantly improved transmission value.

  Although the above-described compositions, coatings, methods and substrates have been applied to vehicle surfaces, they can be used on other surfaces ranging from a range of industrial and personal products, plastics, metals, etc. Will be understood. Therefore, the above description is not intended to limit the present invention only to the field of preferred vehicle surfaces.

  Moreover, while this disclosure describes and illustrates certain preferred embodiments of the invention, it is to be understood that the invention is not limited to these specific embodiments. Rather, the invention includes all embodiments that are functionally or mechanically equivalent to the specific embodiments and features described and illustrated.

Comparison of% transmittance for the 2-coated pearlescent white paint of the present invention and the prior art 2-coated or 3-coated pearlescent white paint film at various paint film thicknesses It is a comparison graph.

Claims (10)

A solid content and a film-forming material, the solid content comprising at least 90% w / w mica, 4-7% w / w TiO ₂ and 0.2-3.0% w / w particulate metal aluminum. A pearly white paint composition. The paint according to claim 1, wherein the solid content comprises 94.0 ± 1% w / w mica, 5.0 ± 1% w / w TiO ₂ and 0.5 ± 0.3% w / w aluminum. Composition.   The paint composition according to claim 1 or 2, wherein the film-forming material is selected from a resin group consisting of acrylic, urethane, polyester, and melamine / formaldehyde.   4. A paint composition according to any one of claims 1 to 3, wherein the formulation base is selected from the group consisting of aqueous, solvent and lacquer bases.   5. A paint composition according to claim 3 or 4 comprising about 7-8% acrylic, about 1% urethane, about 6% polyester and about 5% melamine formaldehyde resin on a w / w basis.   A method of producing a pearly white finish on a substrate, the step of applying the pearly white paint composition according to any one of claims 1 to 5 to the substrate, and curing the composition. Providing the cured finished product on the substrate.   The method according to claim 6, further comprising applying a clear coating to the cured finish and curing the clear coating.   The method according to claim 6 or 7, wherein the substrate is a vehicle body.   A substrate coated with a hardened pearlescent white finish produced by the process of claim 7.   10. A painted substrate according to claim 9, wherein the substrate is a vehicle body.

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