JPH10204340A - Coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-cost coating compsn. that forms a coating film excellent in water repellency and effective esp. for preventing the staining and corrosion due to a water-contg. staining component and for preventing accretion of ice and snow, and compounding a resin compsn. with an org. solvent and a specified amt. of a polyethylene wax. SOLUTION: The resin compsn. is a mixture of a base resin (e.g. an acrylic, vinyl, polyester, alkyd, epoxy, or silicone resin) usually used for a coating material, a resin formed by incorporating functional groups into a base resin such as above-mentioned, and a cross-linker. A polyethylene wax, i.e., an ethylene polymer, having a mol.wt. of about 1,000-10,000 and a softening point of 100-134 deg.C is pref. Any one of high-, medium-, or low-density types can be used. The amt. of the wax compounded is 30-100wt.% of the solids of the resin compsn. The coating film formed from the compsn. has a water contact angle of 110 deg.C or higher and when particles of the wax are projected from the surface, the coating film is hardly wetted by water at 140 deg.C or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel coating composition for forming a coating film having excellent water repellency, and is particularly effective for preventing contamination and corrosion by water-containing contaminants, and avoiding icing and snow.

[0002]

2. Description of the Related Art As a coating composition for forming a water-repellent coating film, a coating composition containing ethylene tetrafluoride powder or graphite fluoride powder is known, but these powders are expensive. Therefore, it lacks versatility and is limited to special applications such as prevention of snow accumulation of communication antennas.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a coating composition which is low-cost and versatile and forms a coating film having excellent water repellency, and is characterized in that a specific amount of polyethylene wax is contained. is there.

That is, the present invention relates to a coating composition containing 30 to 100 parts by weight (solid content) of polyethylene wax per 100 parts by weight of resin solid content.

Hereinafter, the coating composition of the present invention (hereinafter, referred to as “the present composition”) will be described in detail.

[0006] The present composition is a liquid composition containing a resin composition, polyethylene wax and an organic solvent as main components.

As the resin composition, ordinary paint resins can be used. For example, base resins selected from acrylic resins, vinyl resins, polyester resins, alkyd resins, urethane resins, epoxy resins, silicone resins, fluororesins, and the like; or functional groups such as hydroxyl groups, carboxyl groups, epoxy groups, etc. And a cross-linking agent selected from melamine resins, urea resins, polyisocyanate compounds which may be blocked, carboxyl group-containing compounds, epoxy group-containing compounds, and the like. The ratio of the resin having a functional group to the crosslinking agent is 50 to 90 based on the total weight of both components.
%, Especially 65-85%, the latter being 50-10%, especially 35
~ 15% is suitable. These resin compositions form a coating film by drying or curing at room temperature or by heating.

Known polyethylene waxes can be used, and the composition thereof is a polymer of ethylene. The molecular weight of the polymer is preferably about 1,000 to 10,000,
High density type (density 0.96 or more), medium density type (density 0.94 to 0.95) and low density type (density 0.
93 or less). The softening point is 10
A range from 0 to 134 ° C is suitable.

The mixing amount of the polyethylene wax is 30 to 100 parts by weight, preferably 40 to 80 parts by weight, per 100 parts by weight of the solid content of the resin composition. If the amount of the polyethylene wax is less than 30 parts by weight, the water repellency is not sufficient, and if the amount is more than 100 parts by weight, the polyethylene wax is liable to fall off the coating film.

Examples of the organic solvent include hydrocarbons such as hexane, heptane, xylene, toluene and cyclohexane; esters such as methyl acetate, ethyl acetate, ethylene glycol monomethyl ether and diethylene glycol monomethyl ether; Ether systems such as isopropyl ether, ethylene glycol monomethyl ether and diethylene glycol monobutyl ether; alcohol systems such as ethyl alcohol, butyl alcohol and hexyl alcohol; methyl isobutyl ketone, methyl ethyl ketone and isophorone And ketones such as acetophenone; and the like.

The composition may further contain, if necessary, a coloring pigment or the like. Examples of such coloring pigments include titanium oxide, zinc white, carbon black, cadmium red, molybdenum red, chrome yellow, Inorganic pigments such as chromium oxide, Prussian blue, and cobalt blue; organic pigments such as azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, sulene pigments, and perylene pigments; scaly aluminum, mica, and metal oxides So-called metallic pigments having a brilliant or interference effect, such as mica and mica-like iron oxide coated on the surface; and one or more of these can be used.

The present composition can be prepared by mixing and dispersing a resin composition, polyethylene wax, and, if necessary, a color pigment in an organic solvent. The polyethylene wax and the organic solvent are previously mixed in a paste form. It is preferable that this be mixed and dispersed in an organic solvent together with the resin composition. The ratio of the polyethylene wax to the organic solvent in the paste-like mixing is based on 100 parts by weight of both, and the polyethylene wax is 5 to 5 parts by weight.
15 parts and 95 to 85 parts of the organic solvent are preferable. The present composition is particularly suitable for preventing contamination and corrosion due to water-containing contaminants, avoiding icing and snow, etc., for coating objects made of metal or plastic, such as brush, air spray, airless spray, electrostatic coating, and the like. 5 based on the cured coating by dip coating
The coating is applied to a thickness of 80 μm, and the coating is cured at room temperature or by heating. Prior to these coatings, it is also possible to apply a primer coating, an intermediate coating and the like in advance.

The water contact angle of the coating thus obtained is 110
゜ Higher water repellency. The water contact angle of the coating film coated so that the polyethylene wax particles protrude from the coating surface is 140 ° or more, hardly gets wet with water, and can be easily removed even if snow and water-containing contaminants adhere. Can be.

Examples of the present invention and comparative examples will be described below. All parts and percentages are based on weight.

1. Examples and Comparative Examples Example 1 A polyethylene wax was added to 100 parts (solid content) of an equimolar mixture of a hydroxyl group of a hydroxyl group-containing acrylic resin and an isocyanate group of hexamethylene diisocyanate.
A coating composition comprising 80 parts (solid content) of a paste containing 0%.

Example 2 A coating composition comprising 50 parts (solid content) of a paste containing 10% of polyethylene wax per 100 parts (solid content) of a one-part silicone resin.

Comparative Example 1 A coating composition comprising a mixture of the hydroxyl group of the hydroxyl group-containing acrylic resin of Example 1 and the isocyanate group of hexamethylene diisocyanate in an equimolar ratio.

Comparative Example 2 80 parts (solid content) of a fluororesin powder per 100 parts (solid content) of an equimolar mixture of a hydroxyl group of a hydroxyl group-containing acrylic resin and an isocyanate group of hexamethylene diisocyanate. A paint composition that is blended.

Comparative Example 3 A coating composition comprising the one-part silicone resin of Example 2.

Comparative Example 4 A coating composition comprising 80 parts (solids) of a fluororesin powder per 100 parts (solids) of a one-part silicone resin.

2. Performance test results The coating compositions of the above Examples and Comparative Examples were applied to a metal plate with a cured coating film with an air layer so as to have a thickness of 30 to 40 μm.
Dry cured at room temperature. Using the test plate thus obtained,
The contact angle of the coating film was measured, and further, a submersion test, a test for acid resistance and a test for alkali resistance, etc. were performed. The results are as shown in Table 1.

[0022]

[Table 1]

The test method is as follows.

Contact angle: The contact angle with water was measured with a contact angle meter CA-X150 manufactured by Kyowa Interface Science Co., Ltd.

Submersion test: After immersion in tap water (room temperature) for 48 hours, the state of the coated surface and the water contact angle were examined.

Acid resistance: After immersion in a 5% aqueous sulfuric acid solution (room temperature) for 48 hours, the state of the coated surface and the water contact angle were examined.

Alkali resistance: After immersion in a 5% aqueous sodium hydroxide solution (room temperature) for 48 hours, the state of the coated surface and the water contact angle were examined.

Claims (1)

[Claims] 1. A polyethylene wax having a resin solid content of 100
A coating composition containing 30 to 100 parts by weight (solid content) per part by weight.