February 2014 Archives

(12) Vinyl resin paint

This type can be roughly classified into "solution based paints" that use resin solutions as vehicles, and "sol-type paints" that use powdered resins as plasticizer (also with small amounts of solvents). The common characteristics of the coatings are corrosion resistance and especially good alkali resistance. The workability and adhesion are not very good requiring proper primer coatings.

(1) Polyvinyl chloride acetate resin paint

This is a thermoplastic resin solution based paint with copolymer resins of vinyl chloride and vinyl acetate, normally containing 9~15% of vinyl chloride.
This resin dissolves well in a mixture of aromatic hydrocarbons such as ester and ketone. The coatings have excellent water resistance, oil resistance and chemical resistance. but does not have good pigment dispersibility, having high viscosity with poor workability and build-up characteristics.
It is often used as chemical resistant painting on factory equipment, tanks, interior and exterior coatings of pipes, anti-corrosion coatings on mechanical tools, ship bottom coatings, and strippable coatings.

(2) Vinyl-sol paint

The vinyl-sol paint is a paste like paint with vinyl chloride resin fine powder dispersed and suspended in a plasticizer or plasticizer + small amount of solvent.

The type dispersed in a plasticizer is called "Plastisol", and the type dispersed in a plasticizer + solvent is called " Organosol". When these are heated to 170~200°, the resin particles fuse together to form the coatings.

	1.	Since its non-solvent nature, a single coating application of plastisol attains several mm, organosol attains several 1/10 mm layer thickness conventionally unobtainable.
	2.	The thick coatings have excellent corrosion resistance and chemical resistance.
	3.	Excellent in mechanical, chemical, and electrical properties. High baking temperature.
	4.	Special painting procedures are required since viscosity cannot be freely adjusted.

Applications are...

	1.	Roll coating and immersion coating of wrapping paper and fabric as waterproofing.
	2.	Possible to apply embossing and printing on steel and aluminum plates giving leather and cloth like textures with Soundproofing effects. Such painted metal plates are widely used for electrical equipment, construction material, office equipment, metal furniture, vehicles, ship vessels.
	3.	Decorative painting such as wrinkle finish can be obtained by simply spraying.
	4.	Widely used on other applications such as on shipping vessel coatings, and strippable (coatings that can be stripped) paints.

(11) Lacquer

Quick drying solvent based paints are termed as "Lacquer", in general. With oil based paints and synthetic resin paints so far, there are large differences in the molecular weight of the paint and coating, however, with lacquer the molecular weight of the main components of the coating are amply large and the coatings are formed just by the solvents evaporating. Once the coatings are formed, they can be solved in the solvents again.
Depending on the main coating component types, there are cellulose derivative lacquer, vinyl based lacquer, acrylic based lacquer. But when its called simply "lacquer", it points to nitrocellulose lacquer. In addition, there are other classifications also, such as by applications and painting methods, likes of "for wood", "for metals" and "lacquer base coats".

(1) Nitrocellulose lacquer (NC lacquer)

This is a quick drying lacquer type with durable coating widely in use, having nitrocellulose, resin, and plasticizer as the coating components. Alkyd resin, vinyl, acrylic, melamine, etc. are added to nitrocellulose (NC) with cellulose dissolved in nitric acid. Dibutyl phthalate (DBP), dioctyl phthalate (DOP), etc. are used as the plasticizer.
The solvents are the mixed type, not only giving fluidity but the solvents have influences on drying, coating surface conditions, gloss, and as important as having effects on various properties of the coatings. In these cases, mixtures of esters, ketones, and glucose esters, alcohols are used. The NC lacquers are: high-solid lacquer, hot spray lacquer, electrostatic painting lacquer, lacquer base coats.

(2) Etching primer (Wash primer)

High-solid lacquers with increased solid contents excel in gloss, adhesion, and weatherability, and are frequently used for auto repairs and wood working. This a combination of metal surface treatment and anti-rust primer made of polyvinyl butyral (PVB) kneaded together with zinc chromate as anti-rusting pigments, and phosphoric acid added prior to use. On metal surfaces, PVB, zinc chromate, phosphoric acid react in a complex manner to form non-active coatings. This pretreatment is vital for metal painting, especially for corrosion prevention and adhesion improvements on aluminum and galvanized steel sheets.

(3) Acrylic lacquer

These are type of lacquer with the main coating components of thermoplastic acrylic resins such as acrylic acid, methacrylic ester, styrene, and vinyl acetate, forming the coatings by just by evaporation of the solvents. Acrylic lacquers are exceptionally good in transparency, gloss retention, color retention, and weatherability. Especially, the metallic colors are beautiful and used on metal products such as on exterior painting of automobiles, railway vehicles, high quality finishes on home appliances, office equipment, and etc.