January 2014 Archives

(9) Silicone resin paint

A silicone resin is a condensate based on silicon. Pure silicone is not often used as paint, but modified silicone resins with modifying agents such as alkyd, epoxy, phenolic, acrylic, melamine resins are used.
Regardless of whether pure silicone resin or modified silicone resin, the silicone resin paints are well known for the excellent heat resistance, cold resistance, chemical resistance, weatherability and electrical insulation properties.

Pure silicone resin pints are polymers with methyl and phenyl groups, with heat resistance of 200~250℃. With increased amounts of methyl group, the flexibility and water repellency will increase, but the heat resistance will decrease.
The modified silicone resins are of modified with alkyd resin, polyester resin, epoxy resin, acrylic resin, etc. with heat resistance to 150~200℃.
Inorganic filler added silicone resin paints have resistant pigments, aluminum powder, graphite, or a ceramic powder as the additives, with high heat resistance of 300~650℃.

Primary uses for the silicone resin paints are as heat resistant paints for engines, exhausts or heat absorbing tubes, reaction vessel inner surfaces at chemical plants, heaters, furnaces, chimneys, etc.
Also, the silicone resin paints are used for electrical resistant painting and Impregnation on motors, transformers, copper wire, glass woven fabric, and bonding of mica laminates.

(10) Fluorine resin paint

For fluorine resin paints, polymers of fluorine-containing monomers such as ethylene fluoride, fluorinated ethylene chloride, vinyl fluoride, vinylidene fluoride are used. These have excellent heat resistance, chemical resistance, and abrasion resistance.
However, depending on the resin composition and degree of polymerization, solutionizing the inactive resins into paints is difficult, therefore, paints are made in dispersed form or water based emulsions.

The heat resistance temperatures of the dispersion paints are: Tetrafluoroethylene resin (PTFE) 260°, Tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) 200°, Polychlorotrifluoroethylene resin (PCTFE) 180°, Polyvinyl fluoride (PVF) 150°, and etc.
Heat resistance of powder paints are: Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin (PFA) 260°, Tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP) 200°, Ethylene chloride trifluoride ethylene copolymer resin (ECTFE) 150°, Tetrafluoroethylene-ethylene copolymer resin (ETFE) 150°, and etc.

Since they are expensive, the uses are limited to applications especially requiring heat resistance and abrasion resistance, such as on special high-quality surface-treated steel sheets, heat resistant machine parts, kitchenware such as frying pans, pots, and kettles.

(7) Epoxy resin paint

The epoxy resin has an epoxy group on the end and a OH group within the molecule, various modifications and crosslinked reactions (curing) are possible. There are following types.

(1) Room temperature drying epoxy ester paint

The epoxy esters esterified with fatty acid epoxy resins have similar molecular structure very similar to the oil-modified alkyd resin, thus the coating characteristics are also similar. Adhesion and chemical resistance characteristics are excellent. They are used as oil base paints and chemical resistant paints.

(2) Epoxy ester baked-on paint

It is a paint with the alkyd resin of alkyd amino resin paint replaced by epoxy ester. Baking temperature required is somewhat higher at more than 130°. Used as base coatings, chemical resistant paints, printing inks on metals cans.

(3) High temperature baked-on epoxy resin paint

Paint with mixtures of high molecular weight epoxy resin and phenol resin or amino resin as the vehicle. The coating adhesion and chemical resistances are excellent, and are used as chemical resistant paints and can printing inks.

(4) Amine or Polyamide cured resin paint

Two-component room temperature curing epoxy resin coatings composed of polymer of epoxy resin and organic amines, and the epoxy resin paints are normally referred to this type of two-component paints. Although they cure at room temperatures, forced drying at 50〜90°will yield better coating results.

(8) Acrylic resin baked paint

For paints with acrylic resin as main coating element, there are acrylic lacquer (thermoplastic resin), acrylic emulsion paints (thermoplastic), and baked paints (thermoset), with the thermoset acrylic resin baked-on paint being well known.

The nature of the acrylic resin baked-on paints is determined by material monomer, type and content of co-reactive resins, and the molecular weight of the resins. For instance, methyl methacrylate and styrene will harden the coatings, and ethyl acrylate and butyl acrylate will soften the coatings.

Characteristics of the acrylic resin baked-on paints are, [1] Excellent weather resistance, gloss and gloss retention properties, color, color retention properties are excellent, [2] various properties of the coatings are excellent, [3] chemical resistance, good stain resistance, excellent adhesion, [4] requiring higher baking temperature compared to amino alkyd resins at 150° or higher.

They are widely used as the top coats on metals such as for automotive (especially as metallic paints), home appliances, OA equipment, machinery, guardrails, colored surface-treated steel sheets, etc.