Wednesday, 13 May 2015

Silicon_ Polymerized Siloxanes


Chemical structure of Polydimethylsiloxane (PDMS)
Silicon density - p 2328 kg/m³ 

Professor Frederick Stanley Kipping FRS (1863-1949) was an English chemist who was born near Manchester, England. He studied under William Henry Perkin, Jr. at Munich University in Germany, in the laboratories of Adolf von Baeyer. Back in England, Kipping undertook much of the pioneering work into the development of silicon polymers (silicones) at University College Nottingham (later University of Nottingham).
He was the first Sir Jesse Boot Professor of Chemistry at the university. He pioneered the study of the organic compounds of silicon (organosilicon) and coined the term silicon in 1901 to describe polydiphenyl siloxane by analogy of its formula, Ph2SiO, with the formula of the ketone Benzophenones, Ph2CO

Silicon and Polymerized Siloxanes

 [: The word "silicone" is derived from ketone; Dimethyl silicon and dimethyl ketone (a.k.a. acetone) have analogous formulas. Silicon is a polymer that includes silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements. Often mistakenly referred to as silicon, although silicones contain silicon atoms, they are not made up exclusively of silicon, and have completely different physical characteristics from elemental silicon. [1]
[Silicone, by contrast, is a synthetic polymer made up of silicon, oxygen and other elements, most typically carbon and hydrogen. Silicone is generally a liquid or a flexible, rubberlike plastic, and has a number of useful properties, such as low toxicity and high heat resistance. It also provides good electrical insulation. In the medical field, silicone can be found in implants, catheters, contact lenses, bandages and a variety of other things]
His research formed the basis for the worldwide development of the synthetic rubber and silicone-based lubricant industries. He also co-wrote, with Perkin, a standard textbook on organic chemistry.

Silicon (polymerized siloxanes or polysiloxanes) are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements and are one of the most misunderstood chemicals used in the detailing industry, if you consider something like 80% of detailing products use this polymer in one way or another, and thanks to many years of negative marketing it still remains a mystery to many.

Most types of silicon utilized in the auto body and paint industries are water soluble additives used in waxes, polishes and paint protectants. When fatty acids and polydimethyl siloxane derivatives are generated, it creates silicone. Silicon also acts as a lubrication agent, and when added to polish, wax and special coatings, it creates a smooth, slippery finish

Polymers are chemically and thermally inert and available as organic or synthetic polymers, that can be either oil or water-based, some are silicon-based and some don’t contain the element silicone. Applications for polymers span virtually every industry in thousands of applications, which include adhesion, sealing, paint and metal protection, and everything else from integrated circuits to radar defence masking.

Silicone, which is a polymer has in nature a positive charge. You know what happens if you hold 2 magnets to each other with a negative side on one and a positive side on another: they attach themselves to each other very quickly. There are many types of polymer (there are more than 20,000). Silicones are inert, synthetic compounds, with both a low chemical reactivity and low toxicity. Typically heat-resistant, it exhibit good electrical insulation it can be formulated to electrically isolate or provide conductivity, it is thermally stable (from −100 to 250. °C) Although not a hydrophobic, it has the ability to repel water and form watertight seals. It exhibits an excellent resistance to oxygen, ozone and UV-B radiation

Silicon oils also referred to as dimethyl fluids are generally straight chain poly-dimethyl siloxane fluids ranging in viscosity from 0.65 to 100,000 centipoises. The typical ones used in wax or sealants formulations however are between 350 to 10,000 centipoises viscosity. These have no reactivity and help with application or initial gloss. There are some modifications to improve characteristics of these oils by adding certain groups for instance aryl groups improve fire resistance and larger alkyl groups make silicon fluids body-shop safe. Some manufacturer’s use these modified silicon fluids only to claim that the product does not contain silicon oils.

Products that contain silicones (Dimethalsiloxane) are best avoided as they build up over time, adversely affecting polish / compound performance and have a negative effect on waxes, sealants and coatings. Some polymer silicones namely Dimethalsiloxane react with the substrate that it is applied to causing the surface to become difficult to polish often cause surface smearing and negatively affecting any paint protection product durability. Not all polymers are; nor do they all contain the element silicone. Silicon is miscible in most oils, but not water. Water-based dressings are emulsions, which mean that water is the carrier system that contains tiny oil droplets.

What is silicone?
Silicon fluid is relatively short chain inorganic polymer called polydimethyl siloxane; please note the prefix poly before the units of dimethyl siloxane. The chain is not long enough to be typically called a polymer but by the technical definition, it is a polymer. Again we see here, the name "polymer" means less and less every time you see it. The properties of silicon fluids range from very thin, volatile liquids that look and feel like petroleum solvents to thick heavy liquids that look like crystal clear honey. The only difference between the thin liquid and the honey liquid is the number of units in the dimethyl siloxane chain.

What is an amino functional silicone?
Silicon and siloxane; both are considered resins; however siloxane is an amino-functional resin. An amino functional silicones a regular silicon fluid that has been modified slightly. Every so often, instead of a dimethyl siloxane unit, an amino functional siloxane unit has been substituted. The amino functional unit creates a space in the chain where cross linking can occur. So an amino functional silicon can form a durable network.

Automotive body manufacturing plants and paint shops avoid silicones, as they may cause ‘fish eyes’, small, circular craters in the paint finish
Polymers are used for different reasons they all have differing characteristics, i.e. as a paint sealant that contains four different polymers; two are used for durability, one to make the product easy to remove and one to give a great shine.

Silicon Polymer technology

a)       Siloxane (R2SiO) or Polydimethylsiloxane (PDMS) The word siloxane is derived from the words silicon, oxygen, and alkane and is one of several types of silicon (polymerized siloxane, a resin as opposed to an oil) it’s a water-based amino-functional resin, although it contains silicon atoms, they are not made up exclusively of silicon, and have completely different physical characteristics from elemental silicon.

b)       Silicon or Dimethalsiloxane (DMS) usually a petroleum distillate, (PD) solvent-based silicone, which after polymerization (cross-linking) will present an external hydrophobic surface. These penetrating-type, durable silicones oils form a flexible protective shield that prevents penetration of moisture and dirt.

c)        Silicon (Ph2SiO) (Si14) – Silicones are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements. Some common forms include silicon oil, silicon grease, silicon rubber, and silicon resin
Silicon oils also referred to as dimethyl fluids are generally straight chain poly-dimethyl siloxane fluids ranging in viscosity from 0.65 to 100,000 centipoises. The typical ones used in wax or sealants formulations        however are between 350 to 10,000 centipoises viscosity. These have no reactivity and help with application or initial gloss. There are some modifications to improve characteristics of these oils by adding certain groups for instance aryl groups improve fire resistance and larger alkyl groups make silicon fluids body-shop safe. Some manufacturer’s use these modified silicon fluids only to claim that the product does not contain silicon oils.

Most often just a misspelling, as opposed to being confused with Silicone

d)       Silicon (SiO2) is an inert, synthetic compound with a variety of forms and uses. Silicones are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other elements. Some common forms include silicon oil, silicon grease, silicon rubber, and silicon resin. Although silicones contain silicon atoms, they are not made up exclusively of silicon, and have completely different physical characteristics from elemental silicon.

e)        Teflon® PTFE (DuPont): [: a polymer of the monomer tetrafluoroethylene]

Teflon® will help ‘spread ability’ (but then so do silicon oils) it does nothing for durability because of its required application method-although Teflon® is an exceptional product when used as intended; it provides no benefit in a wax or polish.

1) According to G.R. Ansul of DuPont's Car Care Products, Specialty Products Division, "The addition of a Teflon® fluoropolymer resin (PTFE) does nothing to enhance the properties of a car wax.

[We have no data that indicates the use of Teflon® fluoro polymer resins is beneficial in car waxes, and we have not seen data from other people that support this position.]

 Manufacturers of gimmicky, over-hyped products sometimes claim that their products contain Teflon®, hoping that the consumer will believe there is something special about that product.
Ansul also notes that, "Unless Teflon® is applied at 700 degrees F, and using a dissolving chemical C8, it is not a viable ingredient, and is 100 percent useless in protecting the paint's finish." This is hot enough that your car's paint (let alone your car) wouldn't survive.

Information resource-
Grisanti, Stephen "The Truth About Teflon®" Professional Car washing & Detailing, Jan1989)
http://patft.uspto.gov/netacgi/nph-...RS=PN/4,284,668http://www.fluoropolymer-facts.com/w...opolymers.html

Two opposing views from the same company;

b)"Fluoro-science has developed tremendously in recent years. The DuPont fluoro products that are used in the formulation of our products, add a distinctive performance benefit to the products. This has been validated in laboratory tests. For example, the low surface energy created by the fluoro chemistry in wax leads to low coefficients of friction making a wax easier to apply and to buff.
The low surface energy also means that water will "bead" or flow offs the surface more readily.
Surfaces treated with the fluoro chemistry resist the build-up of dirt and grime and makes future clean-ups easier. Teflon® is a fluoro surfactant."
Information resource-
Letter dated 23 Oct 2006, from Jeff DuPont, DuPont's Car Care Products http://www.websitetoolbox.com/ 

The Good, the Bad and the Ugly (Il buono, il brutto, il cattivo)

That a product contains a silicon polymer does not necessarily make that product harmful. Silicon is an inert material and is used primarily to modify or improve certain characteristics; they are sometimes added as a lubricant to provide spread ability thereby making a product easier to apply.

Silicones have a historical bad press as being bad or harmful, nothing could be further from the truth, and this is solely due to negative marketing as people don't really understand what makes them good or bad. Apart from restricting their use in body-shops as they cause ‘fish-eye in freshly painted vehicles. There are thousands of different types from the good to the bad and then the ugly. Silicones are used as active compound in car care products due to their low water solubility, good spreading properties and the shine they impart.

The good types don't make drying towels water repellent because they wash out (silicones can be either oil or water based) and add slickness, gloss and buff ability to a wide variety of products. Most of the sealants so beloved by detailing forums are invariably based on silicon polymer technology.

Silicon
[: more precisely called polymerized siloxanes or polysiloxanes, silicones are mixed inorganic-organic polymers with the chemical formula [R2SiO] n, where R = organic groups such as methyl, ethyl, and phenyl]

Silicones are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements. Some common forms include silicon oil, silicon grease, silicon rubber, and silicon resin.

Many of today's advanced products contain a small amount of silicon oil.  Silicones were first developed in Germany in World War II for the purpose of substituting crude oil with a cheaper and more readily available artificial lubricant. 

Silicon based products must be formulated properly to enhance gloss and durability, silicon acts as a lubricant to repel moisture is not water-soluble, which makes it very difficult to wash off.  Most polymer silicon are water soluble and are sometimes used to create oil in water emulsions, to reduce emulsion particle size and to stabilize them, it is also used to enable wax to spread more easily and help with its surface coverage.

Silicones are any of a class of chemical compounds consisting of long chains of alternating silicon and oxygen atoms, with two organic radicals, typically a methyl (CH3) and a phenyl (C6H5) group, attached to each silicon atom. Although silicones are normally assumed to be chemically inert and very stable; they resist the effects of water, heat, and oxidizing agents

The automotive industry uses silicones as component parts (see polymerisation) in its plastic, vinyl, rubber, paints, and fibreglass as well as in polishes and waxes. Silicones are inert chemical chains that are truly remarkable; there are thousands of different kinds. They can provide substantial benefits even when they make up only a very small percentage of the finished product. As consumers, we come in contact with all types of products containing silicon almost every day of our lives. It’s everywhere. We’ve even been known to eat the product in such things as cooking sprays and food coatings.

Silicones are primarily used to modify or improve certain characteristics; they are sometimes added as a lubricant to provide spread ability thereby making a product easier to apply. Silicon is a chemical polymer that can be engineered to enhance exceptional water repellency, gloss, and slipperiness and bonding properties, Silicones are inert, and are commonly used in automotive products to enhance gloss, make product application and removal easier and improve durability, the functions in a formula that silicones superior to than any other single ingredient.

Though not a hydrophobic, they have the ability to repel water and form watertight seals. They can however affect surface adhesion when applying fresh paint to panels that have not been properly cleaned/prepared, causing  "photo spotting" (Something termed as ‘fisheye’), but as far as car care goes, that's about it.

Silicon has some good and even necessary traits that enhance rubber, plastic and vinyl, at least when it’s the “good Silicone”, Polydimethylsiloxane (PDMS). It’s water-based (siloxane fluid) as opposed to a silicon oil- based., dries to a non-oily hard surface, and doesn’t migrate the plasticizers from the material, less absorption of UV rays and non-dust attracting.

Polydimethylsiloxane (PDMS) belongs to a group of polymeric organosilicon compounds that are commonly referred to as silicones. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological (or flow) properties. However, at short flow times (or low temperatures), it acts like an elastic solid, similar to rubber. In other words, if some PDMS is left on a surface overnight (long flow time), it will flow to cover the surface and mould to any surface imperfections.
It’s optically clear, inert, non-toxic, and non-flammable. It is also called dimethicone and is one of several types of silicon oil (polymerized siloxane), which provides a high gloss shine

Chemists also use silicones to create water-in-oil emulsions, reduce emulsion particle size, to stabilize emulsions, and to improve spreading and coverage of wax products. Most modern silicon formulas are inert; this usually results in a matte finish, as opposed to a slick shiny surface. The best way to describe most forms of silicones to think of it as a man-made wax ester.  All good attributes, but the PDMS silicones tend to be more expensive.

A water-in-oil emulsion silicones part of the protective system in paint and helps the paint look better and provides better durability. This type of Silicon doesn’t harm paint, or anything it is formulated into, especially wax or sealant coatings. Without properly blended silicones, waxes would be difficult to apply and would not have the high gloss and radiance detailers strive for.

Silicon grease
[A waterproof grease made by combining silicon oil with a thickener. Most commonly, the silicon oil is polydimethylsiloxane and the thickener is amorphous fumed silica. Using this formulation, silicon grease is a translucent white viscous paste, with exact properties dependent on the type and proportion of the components] 

Why silicon materials excel in automotive applications
Silicones have unique properties that enable them to thrive in harsh engine compartment, under-vehicle, weather, and driving conditions:

·         They are stable over a wide range of temperatures, from -50 to 200°C (-58 to 392°F) and resistant to thermal shock. This enables flexible joint movement with excellent seal ability.
·         Resist moisture, pressure, salt spray, engine fluids, and UV light.
·         They have stable dielectric properties, even at high frequencies.
·         Have very low water absorption: 0.1% per weight at room temperature.
·         Have excellent sound and vibration damping capabilities.

New Automotive Paint
Silicone-based products are only harmful to new paintwork that is between 60-90 days old. During this period, fresh paint is still releasing solvents (off-gassing). Silicone-based polishes and waxes will coat the paint preventing the paint from drying properly. This can affect the appearance of the paint when it is fully cured.

Amino Functional Silicon
The latest technology has formulated an amino functional Polydimethylsiloxane (PDS) which attaches itself via a physical bond to the microscopic pores in the paint film surface. This type of silicon cross-linking period is twenty four to forty eight hours.
Water should not be introduced to the paint surface until it has fully cured (this includes QD sprays as they contain water) the physical bond attained by an amino functional silicon greatly improves its durability.
Water based paints
Paint is a simple mixture of ingredients including pigments, a binder and diluents, or thinner (in a water-based paint it is water; in a solvent-based paint, it is petroleum solvent)

Automotive paints utilizing modern paint technology using water-based high solid/low solvent urethane that for environmental reasons (low volatile organic compounds (VOC)) produce a much softer and more porous finish; its molecules are not tightly linked together as t has a chain-link type structure, which makes it more porous than acrylic or oil based high solvent content paint systems. For this reason you should be cautious as to what chemicals are allowed to come into contact with the paint surface   

Water-based automotive paint is classified as a semi-permeable membrane that has tensile strength and elongation (elasticity) to enable it to move along with the metal as it expands /contracts due to environmental temperature fluctuations They are essentially low solids paints (up to 60% solvent), but they are legal because deionized water is used as the solvent (water is the most common solvent) as opposed to volatile organic compounds (VOC). In addition to the low solids aspect, waterborne paints have many other properties that help improve the performance and appearance.

Using permanent pigmentations and colorants specifically designed for automotive applications (containing automotive-grade binders). Albeit a non-toxic (less than 0.01-percent VOC) water-based paint, there are no compatibility issues with major-brand urethane and polyurethane clear coats.
The Removal of Silicon- polishing is a mechanical process; silicon is a product that has been designed not to be removed by mechanical abrasion. When using Menzerna, to polish surfaces which have been previously treated with a silicone-based product, a smear may result. It is important to understand why this occurs.

Cause - There are lots of silicon oils on the market. The properties that make silicon so popular with car detailers, and some auto manufacturers, also make it a very difficult product for the polisher to remove. During polishing, the silicon mixes with the excess paint that is being removed from the surface to form a smear.

Can you remove silicon from a clear coat completely? [It is impossible to remove silicon from a painted surface without using a chemical process so aggressive that it dissolves the paint. Wax and grease removers will chemically remove one layer of silicon off at a time but are unable to completely remove all the silicon]. Tests using a spectroscope showed the layers become thinner but the silicon remains. Removing silicon completely can take place over time and involves a lengthy process of oxygen, chemicals, time and sunlight]. [Dr Michael Hauber at Menzerna

Protective Coatings
Understanding dressings is essential; obtaining accurate technical information on automotive care products can be problematic, but detailer’s should be knowledgeable on the dressings sold for tires, rubber, vinyl and leather and their chemical content. Otherwise they are at the mercy of the supplier to provide not only products, but also the technical knowledge and application methodology regarding product usage.

Unfortunately not all suppliers or distributors have the ability or technical knowledge to provide accurate information to the trade; some do not want to divulge what they term ’trade secrets’ as the information might be detrimental to their product sales or company image.

Honest opinion or merely advertising? Commercialism brings with it concerns of honesty and true representation. In other words, it’s difficult to know what is true when someone is motivated by income, i.e. directly targeted at product sales, more so than an unbiased opinion

Silicones are primarily used to modify or improve certain characteristics; they are sometimes added as a lubricant to provide spread ability thereby making a product easier to apply. The automotive industry uses silicones as component parts (see polymerisation) in its plastic, vinyl, rubber, paints, and fibreglass as well as in polishes and waxes. Silicon films can be applied to silica-based substrates like glass to form a covalently bonded hydrophobic coating.

Silicon(Siloxane) oils provide an excellent lubricant that when used as a carrier system in polishes and waxes that makes them easier to apply and remove When used in paints and other coatings it ensures an even flow through a spray nozzle ensuring an even product distribution. It not silicon that you need worry about, just the 'type' (what it’s formulated with) you need to be aware of.

Polydimethylsiloxane (PDMS) [: belong to a group of polymeric organosilicon compounds which are commonly referred to as silicones]. PDMS is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological (or flow) properties.  CAS number - 63148-62-9

PDMS is optically clear, and is generally considered to be inert, non-toxic and non-flammable. It is occasionally called dimethicone and is one of several types of silicon oil (polymerized siloxane).

a) Polydimethylsiloxane (PDS) is water-based silicone, usually a milky-white liquid, that doesn’t contain petroleum distillate solvents that can harm rubber and/or vinyl over time. Water-based dressings use a combination of natural oils and polymers to offer a non-greasy, satin finish.

Some of these products also contain ultra violet radiation (UVR) blocking agents to help keep tires from cracking, fading and hardening. Most, if not all water-based dressings are environmentally friendly / biodegradable, whereas DMS solvent-based silicones are not.

b) Dimethylsiloxane (DMS) a solvent-based silicon dressings - usually a clear greasy liquid that contain petroleum solvents as a cleaning agent can cause the paint layer to delaminate. These penetrating-type silicones form a flexible protective shield that prevents penetration of moisture and dirt. Most silicon dressings leave a never-dry high gloss film. They remove the elasticity from vinyl, rubber and paint; causing them to evaporate out of the substrate, leaving behind a dry inflexible surface. Most high gloss products are based upon DMS silicon oil, the difference between water and solvent based is in the carrier system used. Solvent based products use a hydrocarbon silicon to suspend the product.

When you apply it, the solvent evaporates leaving the dressing's active ingredients (Silicon oil) behind; solvent-based silicones not environmentally friendly / biodegradable

c) 'Paint or Body Shop Safe’ (a product that contains no silicone) car care products that are free of ingredients that could cause surface contamination prior to or during the painting operation in a collision repair shop. Silicon is one; water and oil are the other major painting contamination culprits that cause fish eyes (photo spotting), which look like little craters where the paint pulls away from the centre, which occurs immediately upon spraying.

d) Fisheyes
[: Silicon Contamination; small circular, crater-like openings that appear during or shortly after the spray application. or wax]
 "Photo spotting" or fish eye is caused by contamination of the surface to be sprayed. If the surface to be painted receives the correct preparation it should not cause issues.

Cause
·         Spraying over surfaces contaminated with oil, wax, silicone, grease, etc.
·         Use of thinner/reducer in place of a solvent cleaner.
·         Spraying over previously repaired areas containing "fisheye eliminator" additive.
·         Once the surface ’fisheye, the paint should be polished or cleaned with a chemical cleaner (PrepSol) as something has contaminated the surface. There is no point in sanding down the surface and repainting as the problem will not just go away.
Fisheye look like little craters where the paint pulls away from the centre (looks like a fish eye and hence the name)

Surface Preparation (For Polishing)
There are lots of silicon oils on the market. The high gloss properties that make silicon so popular with car detailers, and some auto manufacturers, also make it a very difficult product for the polisher to remove. During polishing, the silicon mixes with oxidised paint and polish abrasive residue that is being removed from the surface to form a smear. These products and or paint/ polish debris can be removed with a wipe-down process or a specific silicon remover. You may not be able to remove it all but it helps.

When a silicon-free polish works on the surface of paint it uses aluminium oxide spheres, suspended in water and hydrocarbons and a mechanical process to abrade the surface of the paint down to the level of the bottom of the scratch. Silicon cannot be removed this way. Silicon is removed by a chemical means and is designed to resist being removed by mechanical means. Instead the silicon mixes with the blend of paint dust and polish powder and it creates a smear on the paint.

We should differentiate between swirl marks in the silicon layer and swirl marks in the paint underneath. Some polishes may appear to remove the swirl marks in the paint but are really only working on the layer of silicon. So the swirl marks in the paint itself remain unaffected by the polishing and reappear after a few weeks, as the silicon is being removed by time.
·         Hi-Temp's Prep Wash - to prepare a paint surface for polishing, compounding, wax and / or polymer sealant application (especially if changing from a wax to a polymer product) this is a water-based paint cleaner designed to remove all traces of silicone, oil, and buffing residue from any exterior paint surface

·         DuPont PrepSol II™ or Final-Klean - spray onto a 100% cotton or a micro fibre towel and clean the surface, DuPont now also sells the Sonatra Line, which are essentially wipes/towels, pre-moistened with either Prep-Sol or Final-Klean, ideal for all high tech wiping applications, excellent in use both wet and dry with high absorbent capacity

·         Dow Corning® OS-2 Silicon Cleaner and Surface Prep Solvent is a volatile methyl siloxane (VMS) fluid that is compatible with a wide range of materials. It will not harm most substrates, including plastics. OS-2 can be used to remove silicone-based; greases, oils, car wax and car care products, will soften cured silicones to facilitate removal

I would like to think that these articles become an asset to anyone who is new to detailing and to professionals alike, as well as industry experts who seek to advance their knowledge.
I hope the above article was informative. By having some understanding of the ‘What’ and ‘Why’ as well as the ‘How’ along with a little science to help you understand how the chemicals we use react, you can achieve the results you desire.

I would appreciate it if you would share this article as it helps other detailers further their knowledge.
Questions and/ or constructive comments are always appreciated.


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