19-06-2012, 01:54 PM
Pigment
• Pigments are granular solids incorporated into the paint to contribute color, toughness, texture, give the paint some special properties or simply to reduce the cost of the paint. Alternatively, some paints contain dyes instead of or in combination with pigments.
• Pigments can be classified as either natural or synthetic types. Natural pigments include various clays, calcium carbonate, mica, silicas, and talcs. Synthetics would include engineered molecules, calcined clays, blanc fixe, precipitated calcium carbonate, and synthetic pyrogenic silicas.
• Hiding pigments, in making paint opaque, also protect the substrate from the harmful effects of ultraviolet light. Hiding pigments include titanium dioxide, phthalo blue, red iron oxide, and many others.
• Fillers are a special type of pigment that serve to thicken the film, support its structure and simply increase the volume of the paint. Fillers are usually made of cheap and inert materials, such as diatomaceous earth, talc, lime, barytes, clay, etc. Floor paints that will be subjected to abrasion may even contain fine quartz sand as a filler. Not all paints include fillers. On the other hand some paints contain very large proportions of pigment/filler and binder.
• Some pigments are toxic, such as the lead pigments that are used in lead paint
2. Binder, Vehicle or Resins
• The binder, commonly referred to as the vehicle, is the actual film forming component of paint. It is the only component that must be present; other components listed below are included optionally, depending on the desired properties of the cured film.
• The binder imparts adhesion, binds the pigments together, and strongly influences such properties as gloss potential, exterior durability, flexibility, and toughness.
• Binders include synthetic or natural resins such as cement, alkyds, acrylics, vinyl-acrylics, vinyl acetate/ethylene (VAE), polyurethanes, polyesters, melamine resins, epoxy, or oils.
3. Solvent
• The main purposes of the solvent are to adjust the curing properties and viscosity of the paint.
• It is volatile and does not become part of the paint film.
• It also controls flow and application properties, and affects the stability of the paint while in liquid state.
• Its main function is as the carrier for the non volatile components.
4. Additives
• Paint can have a wide variety of miscellaneous additives, which are usually added in very small amounts and yet give a very significant effect on the product.
• Some examples include additives to modify surface tension, improve flow properties, improve the finished appearance, increase wet edge, improve pigment stability, impart antifreeze properties, control foaming, control skinning, etc.
• Other types of additives include catalysts, thickeners, stabilizers, emulsifiers, texturizers, adhesion promoters, UV stabilizers, flatteners (de-glossing agents), biocides to fight bacterial growth, and the like.
• Additives normally do not significantly alter the percentages of individual components in a formulation.
Application
Paint can be applied as a solid, a gaseous suspension (aerosol) or a liquid.
1. As a solid (usually used in industrial and automotive applications), the paint is applied as a very fine powder, then baked at high temperature. This melts the powder and causes it to adhere (stick) to the surface.The reasons for doing this involve the chemistries of the paint, the surface itself, and perhaps even the chemistry of the substrate (the overall object being painted). This is commonly referred to as "powder coating" an object.
2. As a gas or as a gaseous suspension, the paint is suspended in solid or liquid form in a gas that is sprayed on an object. The paint sticks to the object. This is commonly referred to as "spray painting" an object. The reasons for doing this include:
• The application mechanism is air and thus no solid object ever touches the object being painted;
• The distribution of the paint is very uniform so there are no sharp lines;
• It is possible to deliver very small amounts of paint;
• A chemical (typically a solvent) can be sprayed along with the paint to dissolve together both the delivered paint and the chemicals on the surface of the object being painted;
3. In the liquid application, paint can be applied by direct application using brushes, paint rollers, blades, other instruments, or body parts such as fingers.Rollers generally have a handle that allows for different lengths of poles which can be attached to allow for painting at different heights. Generally, roller application takes two coats for even color. A roller with a thicker nap is used to apply paint on uneven surfaces. Edges are often finished with an angled brush.Paint application by spray is the most popular method in industry. Alternate methods are airless spray, hot spray, hot airless spray, and any of these with an electrostatic spray included. There are numerous electrostatic methods available.
Product Variants
1. Primer is a preparatory coating put on materials before painting. Priming ensures better adhesion of paint to the surface, increases paint durability, and provides additional protection for the material being painted. It can also be used to block and seal stains, or to hide a color that is to be painted over.
2. Emulsion paint is a water-based paint used for painting interior or exterior surfaces.
3. Varnish and shellac provide a protective coating without changing the color. They are paints without pigment.
4. Wood stain is a type of paint that is very "thin," that is, low in viscosity, and formulated so that the pigment penetrates the surface rather than remaining in a film on top of the surface. Stain is predominantly pigment or dye and solvent with little binder, designed primarily to add color without providing a surface coating.
5. Lacquer is usually a fast-drying solvent-based paint or varnish that produces an especially hard, durable finish.
6. An enamel paint is a paint that dries to an especially hard, usually glossy, finish. Enamel paints sometimes contain glass powder or tiny metal flake fragments instead of the color pigments found in standard oil-based paints. Enamel paint is sometimes mixed with varnish or urethane to increase shine as well as assist its hardening process.
7. Inks are similar to paints, except they are typically made using finely ground pigments or dyes, and are designed so as not to leave a thick film of binder.
Failure of Paint
The main reasons of paint failure after application on surface are the applicator and improper treatment of surface.
Application Defects can be attributed to:
Dilution
This usually occurs when the dilution of the paint is not done as per manufacturers recommendation. There can be a case of over dilution and under dilution, as well as dilution with the incorrect diluent.
Contamination
Foreign contaminants added without the manufacturers consent which results in various film defects.
Peeling/Blistering
Most commonly due to improper surface treatment before application and inherent moisture/dampness being present in the substrate.
Chalking
Chalking is the progressive powdering of the paint film on the painted surface. The primary reason for the problem is polymer degradation of the paint matrix caused by attack by UV radiation in sunshine.
Cracking
Cracking of paint film is due to the unequal expansion or contraction of paint coats. It usually happens when the coats of the paint are not allowed to cure/dry completely before the next coat is applied.
Erosion
Erosion is very quick chalking. It occurs due to external agents like air,water etc.
Blistering
Blistering is due to improper surface exposure of paint to strong sunshine.
Dangers
Volatile organic compounds (VOCs) in paint are considered harmful to the environment and especially for people who work with them on a regular basis. Exposure to VOCs has been related to organic solvent syndrome, although this relation has been somewhat controversial.
Coating
• Coating is a covering that is applied to the surface of an object, usually referred to as the substrate.
• In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance.
• Coating and printing processes involve the application of a thin film of functional material to a substrate, such as paper, fabric, film, foil or sheet stock.
• Coatings may be applied as liquids, gases or solids.
Resins
• Resin is a natural or synthetic compound which begins in a highly viscous state and hardens with treatment. Typically, resin is soluble in alcohol, but not in water. There are a number of different classes of resin, depending on exact chemical composition and potential uses. There are numerous applications for resins, ranging from art to polymer production, and many consumers interact with products which contain resin on a daily basis.
• Natural resin comes from plants. A classic example is pine sap, which has the characteristic sharp odor of terpene compounds. As anyone who has interacted with pine sap knows, the substance is very viscous, but it hardens over time.
• A number of other plants produce resins, and plant resins have been used by humans for thousands of years. Some plants exude a similar substance called gum or gum resin which does interact with water. Gum tends to be softer and more malleable than resin.
• Humans have been using natural resins for thousands of years. Pine pitch has been used to seal boats, mummies, food containers, and an assortment of other things. It has also been used as a component in varnish, lacquer, inks, perfumes, jewelry, and many other objects. With human technological advances came the realization that resins could be formulated into polymers, and the discovery of synthetic resins followed shortly after.
• Polymers made with “resins” are actually made with synthetic resin, which is cheaper and easier to refine. Synthetic resin is much more stable, predictable, and uniform than natural resin as well, since it is made under controlled conditions without the possibility of the introduction of impurities. Once formed, the resin can be used in the production of plastics, paints, and many of the same substances that natural resin is used in.
Liquid Resin
Thus resin casting is not generally suitable for wide-scale production. Casting supplies and liquid resins are widely available from hardware and craft shops as well as hobbyist websites and catalogs.
The resulting polymer is strong and transparent, which allows acrylic resins to be used for manufacturing aquariums, cell phone displays, taillights for cars, and bathtub liners. Liquid resin material is used in a process called resin casting.
Polyester Resin
Polyester resins are the most widely used resin systems, particularly in the marine industry. By far the majority of dinghies, yachts and workboats built in composites make use of this resin system.
Polyester resins such as these are of the 'unsaturated' type. Unsaturated polyester resin is a thermoset, capable of being cured from a liquid or solid state when subject to the right conditions. It is usual to refer to unsaturated polyester resins as 'polyester resins', or simply as 'polyesters'. There is a whole range of polyesters made from different acids, glycols and monomers, all having varying properties.
There are two principle types of polyester resin used as standard laminating systems in the composites industry. Orthophthalic polyester resin is the standard economic resin used by many people. Isophthalic polyester resin is now becoming the preferred material in industries such as marine where its superior water resistance is desirable.
Epoxy Resins
The large family of epoxy resins represent some of the highest performance resins of those available at this time. Epoxies generally out-perform most other resin types in terms of mechanical properties and resistance to environmental degradation, which leads to their almost exclusive use in aircraft components. As a laminating resin their increased adhesive properties and resistance to water degradation make these resins ideal for use in applications such as boat building. Here epoxies are widely used as a primary construction material for high-performance boats or as a secondary application to sheath a hull or replace water-degraded polyester resins and gel coats.
• Pigments are granular solids incorporated into the paint to contribute color, toughness, texture, give the paint some special properties or simply to reduce the cost of the paint. Alternatively, some paints contain dyes instead of or in combination with pigments.
• Pigments can be classified as either natural or synthetic types. Natural pigments include various clays, calcium carbonate, mica, silicas, and talcs. Synthetics would include engineered molecules, calcined clays, blanc fixe, precipitated calcium carbonate, and synthetic pyrogenic silicas.
• Hiding pigments, in making paint opaque, also protect the substrate from the harmful effects of ultraviolet light. Hiding pigments include titanium dioxide, phthalo blue, red iron oxide, and many others.
• Fillers are a special type of pigment that serve to thicken the film, support its structure and simply increase the volume of the paint. Fillers are usually made of cheap and inert materials, such as diatomaceous earth, talc, lime, barytes, clay, etc. Floor paints that will be subjected to abrasion may even contain fine quartz sand as a filler. Not all paints include fillers. On the other hand some paints contain very large proportions of pigment/filler and binder.
• Some pigments are toxic, such as the lead pigments that are used in lead paint
2. Binder, Vehicle or Resins
• The binder, commonly referred to as the vehicle, is the actual film forming component of paint. It is the only component that must be present; other components listed below are included optionally, depending on the desired properties of the cured film.
• The binder imparts adhesion, binds the pigments together, and strongly influences such properties as gloss potential, exterior durability, flexibility, and toughness.
• Binders include synthetic or natural resins such as cement, alkyds, acrylics, vinyl-acrylics, vinyl acetate/ethylene (VAE), polyurethanes, polyesters, melamine resins, epoxy, or oils.
3. Solvent
• The main purposes of the solvent are to adjust the curing properties and viscosity of the paint.
• It is volatile and does not become part of the paint film.
• It also controls flow and application properties, and affects the stability of the paint while in liquid state.
• Its main function is as the carrier for the non volatile components.
4. Additives
• Paint can have a wide variety of miscellaneous additives, which are usually added in very small amounts and yet give a very significant effect on the product.
• Some examples include additives to modify surface tension, improve flow properties, improve the finished appearance, increase wet edge, improve pigment stability, impart antifreeze properties, control foaming, control skinning, etc.
• Other types of additives include catalysts, thickeners, stabilizers, emulsifiers, texturizers, adhesion promoters, UV stabilizers, flatteners (de-glossing agents), biocides to fight bacterial growth, and the like.
• Additives normally do not significantly alter the percentages of individual components in a formulation.
Application
Paint can be applied as a solid, a gaseous suspension (aerosol) or a liquid.
1. As a solid (usually used in industrial and automotive applications), the paint is applied as a very fine powder, then baked at high temperature. This melts the powder and causes it to adhere (stick) to the surface.The reasons for doing this involve the chemistries of the paint, the surface itself, and perhaps even the chemistry of the substrate (the overall object being painted). This is commonly referred to as "powder coating" an object.
2. As a gas or as a gaseous suspension, the paint is suspended in solid or liquid form in a gas that is sprayed on an object. The paint sticks to the object. This is commonly referred to as "spray painting" an object. The reasons for doing this include:
• The application mechanism is air and thus no solid object ever touches the object being painted;
• The distribution of the paint is very uniform so there are no sharp lines;
• It is possible to deliver very small amounts of paint;
• A chemical (typically a solvent) can be sprayed along with the paint to dissolve together both the delivered paint and the chemicals on the surface of the object being painted;
3. In the liquid application, paint can be applied by direct application using brushes, paint rollers, blades, other instruments, or body parts such as fingers.Rollers generally have a handle that allows for different lengths of poles which can be attached to allow for painting at different heights. Generally, roller application takes two coats for even color. A roller with a thicker nap is used to apply paint on uneven surfaces. Edges are often finished with an angled brush.Paint application by spray is the most popular method in industry. Alternate methods are airless spray, hot spray, hot airless spray, and any of these with an electrostatic spray included. There are numerous electrostatic methods available.
Product Variants
1. Primer is a preparatory coating put on materials before painting. Priming ensures better adhesion of paint to the surface, increases paint durability, and provides additional protection for the material being painted. It can also be used to block and seal stains, or to hide a color that is to be painted over.
2. Emulsion paint is a water-based paint used for painting interior or exterior surfaces.
3. Varnish and shellac provide a protective coating without changing the color. They are paints without pigment.
4. Wood stain is a type of paint that is very "thin," that is, low in viscosity, and formulated so that the pigment penetrates the surface rather than remaining in a film on top of the surface. Stain is predominantly pigment or dye and solvent with little binder, designed primarily to add color without providing a surface coating.
5. Lacquer is usually a fast-drying solvent-based paint or varnish that produces an especially hard, durable finish.
6. An enamel paint is a paint that dries to an especially hard, usually glossy, finish. Enamel paints sometimes contain glass powder or tiny metal flake fragments instead of the color pigments found in standard oil-based paints. Enamel paint is sometimes mixed with varnish or urethane to increase shine as well as assist its hardening process.
7. Inks are similar to paints, except they are typically made using finely ground pigments or dyes, and are designed so as not to leave a thick film of binder.
Failure of Paint
The main reasons of paint failure after application on surface are the applicator and improper treatment of surface.
Application Defects can be attributed to:
Dilution
This usually occurs when the dilution of the paint is not done as per manufacturers recommendation. There can be a case of over dilution and under dilution, as well as dilution with the incorrect diluent.
Contamination
Foreign contaminants added without the manufacturers consent which results in various film defects.
Peeling/Blistering
Most commonly due to improper surface treatment before application and inherent moisture/dampness being present in the substrate.
Chalking
Chalking is the progressive powdering of the paint film on the painted surface. The primary reason for the problem is polymer degradation of the paint matrix caused by attack by UV radiation in sunshine.
Cracking
Cracking of paint film is due to the unequal expansion or contraction of paint coats. It usually happens when the coats of the paint are not allowed to cure/dry completely before the next coat is applied.
Erosion
Erosion is very quick chalking. It occurs due to external agents like air,water etc.
Blistering
Blistering is due to improper surface exposure of paint to strong sunshine.
Dangers
Volatile organic compounds (VOCs) in paint are considered harmful to the environment and especially for people who work with them on a regular basis. Exposure to VOCs has been related to organic solvent syndrome, although this relation has been somewhat controversial.
Coating
• Coating is a covering that is applied to the surface of an object, usually referred to as the substrate.
• In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance.
• Coating and printing processes involve the application of a thin film of functional material to a substrate, such as paper, fabric, film, foil or sheet stock.
• Coatings may be applied as liquids, gases or solids.
Resins
• Resin is a natural or synthetic compound which begins in a highly viscous state and hardens with treatment. Typically, resin is soluble in alcohol, but not in water. There are a number of different classes of resin, depending on exact chemical composition and potential uses. There are numerous applications for resins, ranging from art to polymer production, and many consumers interact with products which contain resin on a daily basis.
• Natural resin comes from plants. A classic example is pine sap, which has the characteristic sharp odor of terpene compounds. As anyone who has interacted with pine sap knows, the substance is very viscous, but it hardens over time.
• A number of other plants produce resins, and plant resins have been used by humans for thousands of years. Some plants exude a similar substance called gum or gum resin which does interact with water. Gum tends to be softer and more malleable than resin.
• Humans have been using natural resins for thousands of years. Pine pitch has been used to seal boats, mummies, food containers, and an assortment of other things. It has also been used as a component in varnish, lacquer, inks, perfumes, jewelry, and many other objects. With human technological advances came the realization that resins could be formulated into polymers, and the discovery of synthetic resins followed shortly after.
• Polymers made with “resins” are actually made with synthetic resin, which is cheaper and easier to refine. Synthetic resin is much more stable, predictable, and uniform than natural resin as well, since it is made under controlled conditions without the possibility of the introduction of impurities. Once formed, the resin can be used in the production of plastics, paints, and many of the same substances that natural resin is used in.
Liquid Resin
Thus resin casting is not generally suitable for wide-scale production. Casting supplies and liquid resins are widely available from hardware and craft shops as well as hobbyist websites and catalogs.
The resulting polymer is strong and transparent, which allows acrylic resins to be used for manufacturing aquariums, cell phone displays, taillights for cars, and bathtub liners. Liquid resin material is used in a process called resin casting.
Polyester Resin
Polyester resins are the most widely used resin systems, particularly in the marine industry. By far the majority of dinghies, yachts and workboats built in composites make use of this resin system.
Polyester resins such as these are of the 'unsaturated' type. Unsaturated polyester resin is a thermoset, capable of being cured from a liquid or solid state when subject to the right conditions. It is usual to refer to unsaturated polyester resins as 'polyester resins', or simply as 'polyesters'. There is a whole range of polyesters made from different acids, glycols and monomers, all having varying properties.
There are two principle types of polyester resin used as standard laminating systems in the composites industry. Orthophthalic polyester resin is the standard economic resin used by many people. Isophthalic polyester resin is now becoming the preferred material in industries such as marine where its superior water resistance is desirable.
Epoxy Resins
The large family of epoxy resins represent some of the highest performance resins of those available at this time. Epoxies generally out-perform most other resin types in terms of mechanical properties and resistance to environmental degradation, which leads to their almost exclusive use in aircraft components. As a laminating resin their increased adhesive properties and resistance to water degradation make these resins ideal for use in applications such as boat building. Here epoxies are widely used as a primary construction material for high-performance boats or as a secondary application to sheath a hull or replace water-degraded polyester resins and gel coats.