Environmental friendly chromium-free insulating paint

Abstract

An environmental friendly chromium-free insulating paint contains the following components: 100 parts by weight of metal dihydrogen phosphate; 10-200 parts by weight of one or more than one of vinyl acetate, acrylic acid, styrene-acrylic acid copolymer or phenolic resin; 1-40 parts by weight of one or more than one of zirconium acetate, zirconium nitrate, zirconium chloride, zirconium oxychloride, zirconium n-propoxide, and zirconium n-butoxid; and 200-500 parts by weight of pure water. The insulating coating obtained by the paint of the present invention exhibits good corrosion resistance, adhesiveness, and heat resistance; the invention successfully realizes the replacement of chromium compounds and therefore realizes the environmental protection of the production process; and the chromium-free insulating paint is applicable to non-oriented silicon steel.

Description

technical field [0001] The invention relates to an insulating coating, in particular to an environment-friendly chrome-free insulating coating which does not contain chromium and can be used for non-oriented silicon steel. Background technique [0002] The surface of the non-oriented silicon steel sheet is generally coated with an insulating coating, which should provide a high level of interlayer resistance, so that the eddy current loss of the stator is minimized after the silicon steel sheet is stacked into the stator material. The manufacturability of the silicon steel sheet requires that the insulating coating must have good adhesion to ensure that it will not fall off from the edge of the silicon steel sheet during punching. Buildup on feed rolls or other equipment wears down the dies used to stamp or shear the laminations. [0003] Traditional insulating coatings often use chromate as a component, but due to its carcinogenicity, its use is increasingly restricted in ...

AI Technical Summary

Problems solved by technology

Phosphate coating can provide excellent insulation performance and heat resistance, but phosphate often contains excessive residual phosphoric acid, so it is easy to cause moisture absorption and stickiness (chip stickiness), and it is necessary to add a stabilizer for residual phosphoric acid

For example, European patent EP1208166B1 uses 100 parts of aluminum dihydrogen phosphate, 28 to 98 parts of acrylic acid-styrene emulsion, 6 to 18 parts of zinc nitrate, 4 to 13 parts of silicon compounds, 18 to 35 g of ethylene glycol, and 3 to 11 g of nonionic Insulating coatings with surfactants, because there is no stabilizer for residual phosphoric acid, show water absorption and stickiness, and at the same time, due to the use of zinc nitrate, their corrosion resistance is affected; US Patent 5955201 uses inorganic silicate particles as residual phosphoric acid. Stabilizer, although effectively avoiding the problem of stickiness, but the inorganic silicate particles are immiscible with the solution system, and it is easy to produce precipitation, and its effect is difficult to reflect when the stirring is uneven; PCT patent application WO2008 / 016220A1 uses hydrogen Cobalt oxide and strontium hydroxide are used as stabilizers for residual phosphoric acid, which can also avoid sticking problems, but both are inorganic particles, which are difficult to mix evenly

In general, the existing phosphate insulating coatings cannot completely replace chromium-containing insulating coatings

Images