Thursday, March 29, 2007

Main Paint Components

Paint consists of 4 main compenents
1. Resin
2. Pigment
3. Special Agents
4. Thinner

First main paint component.
Resin -is also known as binder or film former. It forms of film which adheres to surfaces and ensures as an adhesive for the pigment and other substances. Resin can be found naturally or can be manufactured through petrochemical processes. Binder generally means to "bind together" and is the term is used to describe resin. All resins are a form of polymer. Plastic is a compound manufactured from plant, animal, or petrochemical products. These products can also be used as fuel. The term "film former" usually refer to "binder". In Thailand, it is called glue, which is an appropriate term. In its liquid form, resin has similar characteristics to more common glues.

Category 1: Resin from plant and animal products
1. Produced from oil and rubber such as pine oil, rubber oil, and rubber from black varnish trees. People have long used this type of resin. Various forms of this resin are still in use today. These include filler for leaks in boats and lacquer used in the gold sheeting of Buddha images. Resins in this group that are widely used are:
1.1 Alkyd resin (from vegetable oil): When added with certain chemical substances, heated soya bean oil may be transformed into a film through oxidation. Paints that originate from this resin are oil paints or enamel paint. These give off a turpentine-like odor and can be commonly found in markets.
1.2 Chlorinated rubber resin: is produced from natural rubber that is treated with chlorine. Chlorinated rubber paint is used in metal construction in medium-rough environments.
1.3 Resin that is made from plant fibers and is used most commonly in producing medicine capsules and starch glue. In industrial environments, Nitrocellulose resin is widely used. This form of resin is produced by treatment of the cellulose (as cotton dissolving cotton in various solvents. The result is a sticky glue called Nitro Cellulose resin. Lacquer and industrial lacquer, used for finishing furniture surfaces, contain Nitro Cellulose resin as major component. It is used in the paint industry as well as the manufacturing of explosives.
2. Shellac (from animal products): The basic ingredient of shellac comes from the Coccus lacca, a scaly insect that feeds on certain trees. After feeding, the insect produces a gummy substance through its pores which hardens into a protective coating called "lac". Shellac can be dissolved by heat or alcohol. Shellac can be used to coat wooden surfaces but its film is considered not durable or glossy. As a result, other types of lacquer are used for this purpose.

Category 2: Resin from petrochemical products This resin comes in the form of a plastic or synthetic material. It has the appearance of a natural substance such as synthetic rubber (a kind of soft plastic). It is, in short, man-made material.
1. PVAC (Polyvinyl Acetate Copolymer) is a resin used in plastic paint (for more details, see at the end of the chapter on resin). Even though this paint is not considered resistant against alkaline salt and UV rays, it has been widely used in Thailand for the last 30 years because it is more affordable.
2. TOA Paint (Thailand) first developed ACRYLIC for emulsion paint in Thailand in 1980. Acrylic resin is superior to PVAC resin in every respect. This marked a significant change for the local paints industry as medium to hi-end products began opting for acrylic resin.
3. EPOXY is a type of resin that forms a chemical-resistant film. It is most suited for painting metal structures susceptible to rough weather, such as off-shore industries, chemical factories, and refineries. Epoxy is sometimes applied to concrete surfaces such as floors and factory walls. It is extensively used on structures that require highly durable surfaces, such as hospital operation wards. The disadvantage of epoxy is that its texture does not allow for UV ray-protection. If a surface painted with epoxy is exposed to UV rays for a period of between 5 to 6 months,the paint film will be chalked. However, it still can still provide protection to the surface despite its unpleasant appearance.
4. POLYURETHANE is similar to epoxy but possesses better UV resistance. This type of resin is often used to apply for clear over parquet. If applied along with paint, polyurethane can be used to coat furniture for an extra-glossy finish.
5. FLUOROCARBON is a heat-resistant resin that can also provide protection to surfaces from dirt and small particles. Fluorocarbon is commonly known for its use on Teflon pans (a trademark name of the resin). This material is often used to coat the metal surfaces of a building, such as curtain walls. Fluorocarbon, however, gives surfaces not very high of finish and is also considered to be very expensive. In many cases, this type of resin can be replaced with polyurethane.
6. There is also a third group of resin that does not originate from plant, animal, or petrochemical products. Resin categorized under this group is made from Silica Sand and is used to produce various glasses and mirrors. This production of resin from Silica Sand results in a material known as Silicone Resin. Silicone Resin is an ingredient used to produce heat-resistant paint, best suited for exhaust pipes and incinerators. All of these different resins are the major components of various levels of paint production. Many other types of resin exist, though these are not commonly used in the paints industry.

Second main paint component.
Pigment -Under normal circumstances, when resin dries or hardens, it forms clear film. If manufacturers do not add pigments during this part of the process, the result will be a clear film. The main purposes for pigment use are:
1. to protect surfaces from UV rays
2. to protect metal from oxidization
3. to prevent the resinous exudation from inside of the new resinous wood
4. to provide hiding of the surface
5. to improve surface preparation
6. to produce colors depending on various aesthetic requirements
Pigments can be categorized into 4 groups based solely on their appearance.
1. transparent pigments
2. semi-transparent pigments
3. opaque Pigments
4. extenders

Third main paint component.
Special Agents -Various chemical agents are added to the paint for different purposes. These substances can be divided into the categories as follows:
1. chemical agents that adjust the texture of the paint (agents to control levels of viscosity)
2. chemical agents that add special qualities to the paint (such as leveling agents, matting agents, the anti-bacteria agent Microban)
3. chemical agents that help maintain the stability of the paint (such as preservatives)

Fourth main paint component.
Thinner -Many people in the general Thai public understand that thinner is a type of solvent. Thinner however is a simple description for substances that thin out other substances. These different substances can come in the form of water, oil or solvents.