JP-7854632-B2 - Method for manufacturing an iron rust reduction rust inhibitor.

Inventors

• 野村 英司
• 尾崎 章夫

Assignees

• 株式会社サンエイジ
• アロウィング株式会社

Dates

Publication Date

20260507

Application Date

20211018

Claims (5)

1. A rust-reducing rust-preventive treatment agent (Agent A) for pre- treatment of iron rust in painting on steel substrates, characterized in that it contains a reducing substance that reduces iron rust on the substrate, a reducing phosphoric acid-based mineral acid, and further tannic acid and alcohols with 5 or fewer carbon atoms, A rust reduction and rust prevention treatment agent (Agent B) containing a water- soluble emulsion resin and a lower alcohol with 5 or fewer carbon atoms, wherein the amount of the water-soluble emulsion resin is in the range of 30 to 80% by weight, thereby enhancing the waterproofness of the coating film and further promoting the reduction reaction of iron rust in the layer beneath the applied coating film, A two-component iron rust reduction rust prevention treatment agent characterized by being applied by coating.
2. The two-component iron rust reduction and rust prevention agent according to claim 1, characterized in that the reducing phosphoric acid mineral acid as the iron rust reducing substance in the iron rust reduction and rust prevention agent (Agent A) contains at least one of hypophosphorous acid and phosphorous acid.
3. A two-component iron rust reduction and rust prevention agent according to claim 1 or 2, characterized in that, as a component of the iron rust reduction and rust prevention agent (Agent A), a reducing phosphoric acid-based mineral acid is combined with a reducing phosphoric acid compound, and the reducing phosphoric acid compound contains at least one compound of reducing phosphoric acid of zinc , aluminum, and calcium .
4. A two-component iron rust reduction and rust prevention agent according to any one of claims 1 to 3, characterized in that the iron rust reduction and rust prevention agent (agent B) is formulated with at least one of acrylic emulsion and acrylic silicone emulsion as the water-soluble emulsion resin.
5. A rust prevention method characterized by applying two layers of a rust-reducing rust-preventive treatment agent (Agent A), which reduces iron rust on the steel substrate to prevent rust, and a rust-reducing rust-preventive treatment agent (Agent B), which further promotes the reduction reaction of iron rust, to the substrate in a pretreatment of a steel substrate, wherein the rust prevention treatment is performed using a two-component rust-reducing rust-preventive treatment agent according to any one of claims 1 to 4.

Description

The present invention relates to a technical field concerning rust prevention pretreatment for surface preparation before painting on steel substrates such as iron and stainless steel. It relates to an iron rust reduction rust prevention treatment agent that, when applied to the surface of a steel substrate, reduces existing red rust and brown rust ( Fe₂O₃ ) to black rust ( Fe₃O₄ ) , thereby enabling painting without mechanically removing the iron rust. When painting steel substrates, if the iron rust present on the surface is not removed, the iron rust layer will expand due to the progression of oxidation of the steel, and the paint film will deteriorate and peel off due to reduced adhesion. Therefore, when painting steel substrates, it was essential to pre-treat the substrate by mechanically removing the iron rust present on the steel substrate using sandpaper, scraping, or sandblasting. This pre-treatment of the substrate before painting required a great deal of effort, and there was a strong demand for reducing this pre-treatment effort. As a countermeasure, it had been proposed to incorporate phosphoric acid compounds such as phosphoric acid and zinc phosphate into the primer paint, but their penetration into the iron rust and reducing power were small, and they were not satisfactory in terms of the rust prevention and durability of the paint film. Prior Patent Documents Japanese Patent Publication No. 2004-338236 Japanese Patent Publication No. 2005-105337 Japanese Patent Publication No. 2009-40929 In the present invention, the reducing mineral acid in the iron rust reduction rust-preventive treatment agent (Agent A), which has the function of reducing iron rust (red rust, brown rust), is a reducing phosphoric acid and its compounds, which have high rust-preventive capabilities. Phosphorous acid and hypophosphorous acid are particularly preferred. These reducing phosphoric acid-based mineral acids react with iron rust to reduce iron oxide and also react with steel substrates to form reduced iron phosphate, thereby exhibiting rust prevention properties. The blending ratio of reducing phosphoric acid-based mineral acids is preferably 0.5 to 30% by weight in the paint. If the blending amount of reducing phosphoric acid-based mineral acids is less than 0.5% by weight, the rust prevention performance decreases, and if it exceeds 30% by weight, the coating film strength and water resistance decrease. Regarding the reducing mineral acid in the above-mentioned iron rust reduction rust inhibitor (Agent A), reducing phosphoric acid may be added along with reducing phosphoric acid, or reducing phosphoric acid compounds may be added to enhance rust prevention ability. Preferred reducing phosphoric acid compounds include iron phosphate, calcium phosphate, magnesium phosphate, aluminum phosphate, iron hypophosphate, calcium hypophosphate, magnesium hypophosphate, and aluminum hypophosphate. It is preferable to include these reducing phosphoric acid compounds in the iron rust reduction rust inhibitor (Agent A) at an amount of 0.5 to 20% by weight. The tannic acid used in the iron rust reduction rust inhibitor (Agent A) of the present invention can be persimmon tannin, bark extracts of acacia, mangium, radiata pine, etc., but it is preferable to use tannic acid extracted and purified from gallnuts. The amount of tannic acid in the iron rust reduction rust inhibitor (Agent A) is preferably 1 to 30% by weight. If the amount of tannic acid is less than 1% by weight, adhesion to rust and rust prevention will decrease. If it exceeds 30% by weight, the water resistance and coating performance will decrease significantly. In the present invention, the iron rust reduction rust-preventive treatment agent (Agent A) preferably contains a lower alcohol with 5 or fewer carbon atoms to enhance the penetration of tannic acid and reducing phosphoric acid compounds. Examples of lower alcohols with 5 or fewer carbon atoms include methanol, ethyl alcohol, propanol, butanol, and pentanol, with ethanol and n-propanol being particularly preferred in terms of penetration and safety. The amount of alcohol with 5 or fewer carbon atoms is 1 to 50% by weight, and a concentration of 10 to 40% by weight is particularly desirable in terms of penetration and coating film strength. In the present invention, the water-soluble emulsion resin to be contained in the iron rust reduction rust prevention agent (Agent B), which is used to promote the reduction reaction and enhance the waterproofness of the coating film after application of the iron rust reduction rust prevention agent (Agent A), can be acrylic resin emulsion, acrylic-vinyl acetate resin emulsion, acrylic-ethylene vinyl acetate resin emulsion, acrylonitrile-vinyl chloride-vinylidene chloride copolymer emulsion, acrylic urethane resin emulsion, acrylic epoxy resin emulsion, acrylic silicone resin emulsion, etc., and these can be used. For the water-soluble emulsion resin used in the iron rus