Coating composition for solar cell protective covers

Abstract

The invention provides a solar cell protective cover which is not impaired in the transparency satisfactory for the protective cover for solar cells and has excellent room-temperature workability, solvent resistance, weather resistance and endurance; and a curable fluororesin coating composition capable of forming the cover. A curable fluororesin coating composition for solar cell protective covers comprising (A) a curable fluororesin, (B) a curing agent, and (C) a solvent, which is to be applied either directly to a transparent resin layer (II) formed on the side of a solar cell module (I) to be irradiated with sun rays or to a primer layer (IV) previously formed on the layer (II) and thus form a top coat layer (III) made of a cured fluororesin.

Description

technical field [0001] The present invention relates to a protective cover of a solar cell and a curable fluorine-containing coating composition for forming the protective cover. The protective cover of the solar cell has transparency, solvent resistance, water resistance (moisture permeability resistance), weather resistance Excellent durability, durability, film hardness, gloss, and environmental protection. Background technique [0002] Today, glass panels are used to protect solar cells. However, glass is heavy and brittle, and therefore light, transparent, and high-refractive polycarbonate plates or transparent resin plates such as acrylic resin plates have been proposed as substrates instead of glass plates. However, these transparent resins are poor in weather resistance, chemical resistance, scratch resistance, stain resistance, etc., so they have not replaced glass plates so far. [0003] In addition, fluororesins have excellent weather resistance, low refractive ...

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Problems solved by technology

[0012] However, although these fluororesins are soluble in common solvents, even for the curable fluorine-containing copolymers in Japanese Patent Publication No. 8-32847, the total amount of hydroxyl value and acid value introduced is also 30 mgKOH / Within g, and in the examples, the copolymer whose solubility in mineral oil was confirmed has a hydroxyl value and an acid value as low as 5 mgKOH / g, and its curability is not sufficient, so it cannot be expected to be an advantageous feature as a fluororesin. Solvent resistance, weather resistance, durability, etc. have been improved

[0013] On the other hand, in the field of solar cells, Japanese Patent Application Laid-Open No. 59-198773 proposes the use of fluororesin paint as a solar cell protective cover. Since the coating film is directly formed on the solar cell module, as a protective cover, Fluororesin coating film has problems in terms of strength

[0014] In Japanese Patent Application Laid-Open No. 2-123771, it is proposed to use a fluororesin having a fluorine-containing alicyclic structure for a solar cell, but it is difficult to introduce a cross-linking site to the fluororesin, so it cannot sufficiently improve the requirements for a protective cover for a solar cell. Solvent resistance, weather resistance, durability, etc.

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