JPS5931545B2 - heat reflective enamel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the production of paint and varnish coating compositions;
More specifically, it relates to heat reflective enamel.

The present invention is most advantageously used for protection against atmospheric influences and for reducing heat build-up on metal surfaces, in particular for painting external surfaces of aircraft fuel tanks and other applications,
Thus, it can be used on the external surfaces of static and mobile tanks for volatile liquid products, as well as on the decks of tankers for the transportation of liquid fuels. White enamels based on the use of acrylic resins and other vehicles and containing as pigments anatase and rutile titanium dioxide, zinc oxide, lead sulfate, lead carbonate, magnesium oxide and other compounds are known in the art. (For example, see the specifications of British Patent No. 948270 and British Patent No. 795464).

Dark heat reflective coatings are absolutely necessary for certain applications, for example as deck coatings for oil tankers.

In the above cases, brightly colored paints can have an adverse effect on the working conditions and operation of deckhands in bright sunlight. Therefore, there is a need in the industry for the development of dark colored heat reflective enamels.

One commonly known heat reflective formulation is a green penta-alkyd enamel as a deck coating for oil tankers.

This heat reflective pentaalkyd enamel is lemon chrome,
This is an alkyd resin solution in which iron blue and iron oxide red pigments are dispersed.

However, closely related to their formulation, said heat-reflecting enamels have poor heat-reflectivity, insufficient weather resistance and short coating life.

By combining these factors, large losses of oil products can be avoided when the enamel is used in tanks for storing and transporting oil products or on the decks of oil carriers;
and the frequent need for repainting.

Product loss due to evaporation can be reduced by minimizing heat build-up on the painted surface.

An indirect method for evaluating the heat reflectivity of coatings under laboratory conditions is to measure the temperature on the back side of a coated metal specimen irradiated with an incandescent lamp. For the pentaalkyd enamels described above, this temperature is as high as 75°C.

This indicates the low heat reflection properties of the pentaalkyd enamel. In order to reduce the accumulation of heat due to solar radiation on the surface to be protected, enamels should be used that are highly reflective in the visible spectral range, and more particularly in the infrared spectral range.

Dark heat reflective enamels containing weatherable vehicles, pigments, extender pigments, and solvents are currently known in the art (e.g., U.S. Pat. No. 3,577,379, U.S. Patent Class 2
60-40).

Said enamel is obtained by dispersing in a resin solution a pigment mixture, an extender pigment, a drying agent such as cobalt naphthenate, and various additives such as stabilizers and antioxidants.

The above pigment mixture contains the pigments necessary to impart a dark color to the enamel, such as lead chromate, molybdenum orange, phlotanine blue, etc., and a highly infrared reflective material (0.2 to 2.5 microns), such as quinacridone red. spectral range). The extender pigments used in the heat-reflecting enamels are either siliceous materials or mixtures of siliceous materials and baryta (barium sulfate).

Vehicles used include styrenated alkyd resins, chlorinated paraffins, and the like.

A typical formulation of the heat-reflecting enamel is as follows.

Thus, in parts by weight, it is observed that the above formulation contains diethylamine as a stabilizer and cobalt naphthenate as a desiccant.

Antioxidants may be of any conventional type. The heat reflection properties of the heat-reflecting enamel are not high enough, as evidenced by the back side temperature of the painted coupons being equal to 72°C.

At temperatures of this order, significant oil product losses are observed. The paint life is equivalent to 9 months, which is not long enough.

Furthermore, although the above formulation contains quinacridone red, the technology for producing this pigment is a multi-step process and is rather complex as it generates a large number of by-products. In view of the disadvantages outlined above, heat reflective enamels of the above formulation are not suitable as deck coatings for tankers transporting oil products. The main objective of the present invention is to provide an optimal formulation for heat-reflective enamels with a high degree of heat-reflectivity and increased useful life by selecting appropriate ingredients.

In view of this main object, a heat-reflecting enamel is provided which comprises a weathering vehicle, a pigment, an extender and a solvent, which according to the invention is further treated by pyrolysis with titanium dioxide or metatitanic acid. It contains the products of thermal interaction between a nickel compound and antimony trioxide to form nickel oxide, and ammonium dichromate or an alkali metal dichromate.

The above usage amounts are shown in parts by weight as follows. In the enamel, the constituent components have the following proportions expressed in parts by weight.

In other words, the heat-reflecting enamel formulated as described above is
more advanced compared to the prior art heat reflective enamel as evidenced by the back side temperature of the painted specimen corresponding to 66° C., which is 6° C. lower than that of the prior art heat reflective enamel. It has heat reflective properties. The paint life of the heat reflective enamel formulated in accordance with the present invention is three months longer than that of the prior art dark enamel, and the physical properties of protection remain beyond the useful life.

With the enamel constituents used in the proportions indicated above,
The desired level of heat reflectivity was achieved, yet the physical properties of protection were ensured.

While these and other objects and novel features of the invention are set forth in the claims, the invention will become more fully apparent from the following detailed description of the embodiments.

In producing the heat reflective enamel of the present invention, pigments,
The starting ingredients including extender pigment, weathering vehicle and solvent are charged to a melt mixer.

The dissolving mixer may be of any type. The mixture is then pumped into a mill. The mill is a ball mill,
It may be a vibratory mill or some other milling device. The milled product is then sent to a mixer for color toning, additive mixing, and viscosity control to produce the finished end-use product. The pigments used in the formulation are the products of thermal interaction between titanium dioxide or metatitic acid, a nickel compound that thermally decomposes to give nickel oxide, antimony trioxide, and ammonium dichromate or alkali metal dichromate.

Any inorganic pigment can also be used, such as chromium oxide, zinc oxide, titanium dioxide, iron oxide red, or primer grade zinc yellow, as well as phthalocyanine blue as an organic pigment. Extender pigments that can be used in the formulation may be of any mineral type, such as carbonate, also known as dolomite or calcite, baryta, or magnesium silicate, also known as talc.

Weatherable vehicles that can be used include alkyd resins, epoxy resins modified with drying oil fatty acids (epoxy ester resins), resins modified with formaldehyde and diphenylolpropane, acrylic resins, polyurethanes, combinations of vinyl chloride and vinyl acetate, etc. Including copolymers and others. Suitable solvents may be any organic solvent such as acetone, butanol, xylene, ethanol, butyl acetate, ethylene glycol acetate, methyl ethyl ketone or mineral spirits.

The thermal interaction product is obtained as follows. 100 kg of titanium dioxide or metatitanic acid (based on the equivalent amount of titanium dioxide), nickel sulfate, or some other nickel compound (based on nickel oxide) that can be thermally decomposed to produce nickel oxide. A starting mixture consisting of 3 to 321 < g), 15 to 35 kg of antimony trioxide, 2 to 5 kg of ammonium dichromate or alkali metal dichromate, based on the corresponding amount of chromium oxide, and 2511 g of water is prepared in the conventional manner. Grind and dry using technology to 1150 to 1
Calcining within a temperature range of 200° C. and then wet milling in a ball mill, vibratory mill or any other milling equipment.

This thermal interaction product of titanium dioxide or metatitanic acid, a nickel compound that thermally decomposes to form nickel oxide, antimony trioxide, and ammonium dichromate or alkali metal dichromate is combined with a high degree of pigmentary properties. It also features a high degree of light fastness, chemical resistance (insolubility in acids and alkalis), and water resistance.

The pigmentary properties of the product are evaluated by the following properties: color, hiding power, oil adsorption, and water-soluble salt content.

The product is yellow in color, has a hiding power of 65 L♀, has an oil adsorption of about 17 to 209 oils per 1009 of pigment product, and a water-soluble salt content of 0.2%. The heat reflectance of this paint is measured under laboratory conditions using the following procedure.

One side of the sample metal strip is coated with the enamel to be tested in four layers to a total thickness of 100 to 120 microns.

Each enamel layer is dried at a temperature of 120±5° C. for 1 hour. The dried coded specimen was placed under an incandescent lamp of 5000 W class, mounted horizontally in a plastic foam chamber with dimensions of 25 x 140 x 260 mm, and a hole of 20 m 1 L in diameter was inserted to allow measurement of the temperature on the back side of the specimen. Fix it to the bottom with a The distance between the plastic foam chamber and the incandescent lamp is such that the temperature on the black enamel back side of the specimen corresponds to 80±2°C. Temperature measurement is performed using a small electric thermometer 4 minutes after the start of heating.

The following representative examples further set forth the features and particular advantages of the invention and illustrate certain features of the invention.

Example 1 Green heat-reflective enamel prescription (parts by weight): Butyl acrylate, styrene, methacrylic acid copolymer green heat-reflective enamel prescription (parts by weight): The heat-reflective properties and weather resistance properties of the above enamel were It is shown in Table 1 below.

Example 2 Green heat reflective enamel formulation (parts by weight): The heat reflective properties and weather resistance properties of the above enamel are shown in Table 1 below.

Example 3 Brown heat reflective enamel formulation (parts by weight): The heat reflective properties and weather resistance properties of the above enamel are shown in Table 1 below.

Example 4 Blue-green heat-reflective enamel formulation (parts by weight): Blue-green heat-reflective enamel formulation (parts by weight): The heat-reflective properties and weather resistance properties of the above enamel are shown in Table 1 below.

Example 5 White heat reflective enamel formulation (parts by weight): The heat reflective properties and weather resistance properties of the above enamel are shown in Table 1 below.

Example 6 White heat-reflecting enamel formulation with yellowing (parts by weight): The heat-reflecting properties and weathering properties of the above enamel are shown in Table 1 below.

Example 7 Blue-green heat-reflective enamel prescription (parts by weight): Blue-green heat-reflective enamel prescription (parts by weight): The heat-reflective properties and weather resistance properties of the above enamel are shown in Table 1 below. Example 8 Green heat-reflective enamel prescription (Parts by weight): The heat reflection properties and weather resistance properties of the above enamel are shown in Table 1 below.

Example 9 Maroon heat reflective enamel prescription (parts by weight): The heat reflective properties and weather resistance properties of the above enamel are shown in Table 1 below.

Example 10 Green heat reflective enamel formulation (parts by weight): The heat reflective properties and weather resistance properties of the above enamel are shown in Table 1 below.

Example 11 Green heat reflective enamel formulation (parts by weight): Oleoresinous vehicle 100 Zinc yellow (primer grade) 62 Phthalocyanine blue 8 Micronized baryta 28 Metatitanic acid, nickel sulfate, antimony trioxide and ammonium dichromate 32 Interaction Product Green Heat Reflective Enamel Formula (parts by weight): Mineral Spirits and Xylene 135 The heat reflective and weathering properties of the above enamel are shown in Table 1 below.

Displayed below are the heat reflective and weathering properties of the enamel paint of the present invention, but all other physical properties of the coating (tensile strength, flexural strength, hardness, adhesion, etc.) are also included. This corresponds to this.

Claims (1)

[Claims] 1 100 parts by weight of weathering vehicle, 30-80 parts of pigment
parts by weight, extender pigment 1 to 60 parts by weight, solvent 90 to 84 parts by weight
0 parts by weight, and further 100 parts by weight based on titanium dioxide of a compound selected from the group consisting of titanium dioxide and metatitanic acid.
3 to 32 parts by weight, based on nickel oxide, of a nickel compound that thermally decomposes to produce nickel oxide, 15 to 35 parts by weight of antimony trioxide, and ammonium dichromate and alkali metal dichromate. 1 product due to thermal interaction with 2 to 5 parts by weight based on chromium oxide
A heat reflective enamel characterized in that it contains 5 to 60 parts by weight.