JPH04270653A - Colored fluorine resin-coated product - Google Patents

Abstract

PURPOSE:To obtain a fluororesin-coated product colored variously over a broad range due to the coating of a single-tier fluorine resin layer without impairing features such as adhesiveness with a metal substrate and the non-tack of the rear. CONSTITUTION:Pigment sticks to the fine uneven surface of a substrate and a fluorine resin which does not contain pigment substantially is laminated on the pigment.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to colored fluororesin coatings, and more particularly to colored fluororesin coatings that are colored without reducing properties such as adhesion to substrates and non-stick properties of the surface. It is.

0002

[Prior art] Fluororesin has excellent non-stick properties and chemical resistance, so it can be used in frying pans, pots, hot plates, etc.
It is used in a wide range of applications, including kitchen equipment such as inner pots for jar rice cookers, food containers, electrical products, the food industry, and the electrical and mechanical industries.

[0003] Conventionally, these fluororesin coatings have mainly been colorless and transparent through which the underlying color can be seen through, or monotone such as white, gray, or black, and at best only a metallic tone can be obtained by adding metallic luster to these coatings. It wasn't. However, in recent years, the need for color has increased, especially in general products such as household goods, and with the release of refrigerators that allow you to customize colors, color, which was previously considered a secondary function, has become essential. It has become.

However, since fluororesin has good chemical resistance, there are almost no solvents that can dissolve it, and it is difficult to use a processing method in which an aqueous dispersion or powder is coated on the adherend and then baked at high temperature. However, organic coloring agents such as dyes could not be used because they denatured due to heat.

On the other hand, when coloring with inorganic pigments such as red iron or ultramarine blue, sufficient color development cannot be obtained with a small amount, and when added in a large amount, the main functions such as adhesion to the adherend and non-stick properties of the surface are impaired. There were problems such as significant damage.

[0006] Therefore, it is possible to incorporate carbon black or titanium oxide, which can harmonize with the color of the substrate to be adhered and provide good color development, in a relatively small amount that does not significantly impair these main properties. However, only monotone colors such as white, gray, and black could be obtained.

On the other hand, fluororesin compositions coated on articles that require wear resistance, such as frying pans, are blended with mica, which has been used for sliding materials for a long time, to improve wear resistance. As a result of this secondary effect, a metallic color tone is obtained. However, if only mica is blended, significant color unevenness will occur due to variations in coating film thickness due to insufficient hiding power as a pigment.
It has been common sense to use metal powder, silica, alumina, carbon, titanium oxide, etc. in combination.

[0008] As an example of this, Japanese Patent Application Laid-Open No. 52-103
No. 86, Special Publication No. 56-501277, Japanese Patent Publication No. 56-1
No. 03257 is mentioned. These methods disclose the addition of metal flakes, mica, or pigment-coated mica to fluororesin, but the main objective is to improve coating film strength such as scratch resistance and abrasion resistance, and also to prevent color unevenness. It does not exclude the use of metal powder, silica, alumina, carbon, titanium oxide, etc., which are added within the range of common sense, and some require the addition of a heat-resistant binder.

[0009] In order to use such additives, in Japanese Patent Application Laid-open No. 52-10386 and Japanese Patent Application Publication No. 56-501277, the inherent non-adhesiveness of fluororesin is significantly impaired, so fluorine is added to the surface. It has become necessary to apply a top coat consisting only of resin or a top coat with a reduced concentration of mica, or it has been necessary to use it only as a base for fluororesin coating, as in JP-A-56-103257. Also,
As for color tone, as with compositions that do not contain mica, the pigment content is limited in order to minimize the decline in adhesive strength and non-stick properties, and currently only monotone metallics can be obtained.

0010

[Problems to be Solved by the Invention] In view of the above, the invention of the present application has been proposed to increase the width by coating with a single fluororesin layer without deteriorating the properties such as adhesion to the metal substrate or non-adhesion of the surface. The objective is to obtain a fluororesin coating colored in a wide range of colors.

[0011]

[Means for Solving the Problems] The colored fluororesin coating of the present invention has a pigment attached to a substrate having fine irregularities.
It is characterized by having a fluororesin layered thereon. Note that the above-described present invention includes at least the following embodiments. stomach. The above-mentioned colored fluororesin coating of the present invention, in which the pigment is attached to blasting sand and sandblasted, so that the pigment is physically embedded and in close contact with the surface of the base material. B. The above-mentioned colored fluororesin coating of the present invention is formed by depositing a pigment into fine irregularities formed by electrochemical or chemical etching or into micropores of an anodic oxide film provided thereon.

0012

[Operation] As the substrate used in the present invention, various types of glass, ceramics, and metal base materials such as aluminum, aluminum alloy, iron, and stainless steel can be used. As the pigment, any inorganic heat-resistant pigment including carbon, titanium oxide, graphite, graphite fluoride, iron oxide, ultramarine, etc. can be used without particular limitation.

Next, a method for depositing a pigment on a substrate will be described. If the base material is glass, ceramics, etc.
By adhering the pigment to blasting sand in advance and performing sandblasting using this blasting sand, the pigment is firmly embedded and adhered to the base material while forming irregularities for making the fluororesin adhere to the surface of the base material. This method can also be successfully applied when the base material is metal.

[0014] In addition, in the case of metal substrates, fine irregularities formed by chemical or electrochemical etching,
The pigment can be deposited in the form of a solution, or an anodic oxide film can be formed and the pigment can be deposited by impregnating the pores with a solution or by electrophoresis. Further, after forming the anodic oxide film, alternating current is applied in a metal salt bath, and substantial pigment deposition can be performed by alternating current electrolytic coloring.

In the present invention, the fluororesin used is, for example, polytetrafluoroethylene (PTF).
E), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE) or Ethylene-chlorotrifluoroethylene copolymer (EC
TFE) etc.

[0016] The fluororesin is not only a resin powder, but also an aqueous dispersion of a fluororesin obtained by an emulsion polymerization method, a dispersion of a fluororesin powder dispersed in an aqueous medium, an organosol of a fluororesin, or an emulsion of an organosol in water. It can be used in any form.

[0017] Since it is not necessary to add a pigment to the fluororesin layer for coloring, it does not cause an increase in pinholes or a decrease in non-adhesiveness. Incidentally, this does not preclude the addition of a scale-like filler such as mica to improve the wear resistance of the surface.

[0018]

[Examples] Examples of the present invention will be described below. Example 1 A stainless steel substrate was sandblasted using blasting sand coated with ultramarine blue to obtain a blue rough surface. On top of this,
PFA powder particles (manufactured by du Pont MP102
) 35% by weight, PFA particles (average diameter 0.4μ)
A dispersion consisting of 15% by weight, 6.5% by weight of surfactant, and 43.5% by weight of water was coated, and after drying, it was sintered at 380° C. for 30 minutes. A beautiful blue coating was obtained, with good non-adhesion and corrosion resistance.

Example 2 Aluminum alloy plate (thickness 2.5 mm, Kobe Steel, Ltd.)
An electrochemical etching process was performed using an ASB material (manufactured by ASB Co., Ltd.) as an anode in an ammonium chloride aqueous solution with an amount of electricity of 25 coulombs/cm2 to form fine irregularities on the surface. Furthermore, after anodizing this surface in 5% sulfuric acid, (NH4)2
SO2 30g/l, CuSO4 2g/l, pH
Apply 25V alternating current for 1 minute in a bath of 3.5 to 3.6,
It was electrolytically colored blue-green. On top of this, PTFE (D-1
F: After coating and drying (manufactured by Daikin),
Sintering was performed at 00°C for 15 minutes to obtain a fluororesin coating. A fluororesin coating with a strong adhesive strength of 2.3 kg/cm2, excellent corrosion resistance, and a bluish-green appearance was obtained.

[0020]

According to the present invention as described above, colored fluororesin coatings with excellent adhesion to substrates, non-adhesive surfaces, and corrosion resistance, and in a variety of colors can be obtained.

Claims (1)

[Claims] 1. A colored fluororesin coating, characterized in that a pigment is adhered to a substrate having fine irregularities, and a fluororesin substantially free of pigment is laminated thereon.