Metal working fluids, especially the water-miscible metal working fluids, are complex, multi-component systems that have to meet a wide range of requirements.
The main components are the base oil, which has a lubricating effect, and water, which provides good cooling.
To make oil and water compatible, surfactants are used. In addition, various standard and special amines are used as pH buffers and for corrosion protection. To prevent foaming of the metal working fluid, antifoams are used. Wetting agents improve the wetting of the metal by the metal working fluid and dispersing agentsensure that solid particles are kept in suspension, do not settle and do not lead to clogging.
Solvents are liquids that are capable of dissolving solids.
Solvents are usually understood to mean organic solvents – strictly speaking, however, water is also a solvent, since it dissolves salts, for example.
Typical organic solvents include alcohols, esters, ketones, glycol ethers and aliphatic and aromatic hydrocarbons.
When selecting solvents, the principle of “like dissolves like” must be observed, i.e.polar substances dissolve in polar solvents, nonpolar substances in nonpolar solvents.
Many plastics (synthetic polymers) are hard and brittle at room temperature. So-called plasticisers are used to make them more flexible and suitable for a wide range of applications. These are usually esters that dissolve in the plastic and improve the mobility of the individual polymer molecules in relation to one another – a molecular lubricant, so to speak.
Surfactants are intermediaries between different worlds. They are needed to make water-insoluble liquids compatible with water (emulsions) or to detach dirt particles from textiles and prevent them from settling again.
Surfactants consist of a water-loving (hydrophilic) part and a water-repellent, oil-loving (hydrophobic or lipophilic) part. The hydrophilic part of the surfactant molecule is in the water, while the hydrophobic part is in the water-insoluble liquid or on the dirt particle.
Surfactants can also stabilise foams. If this is undesirable, the foam can be destroyed by the use of antifoams, with PU foams (e.g. for mattresses, shoe soles and foam boards) the effect is desired, so here special silicone surfactants are often used.
Starch, like cellulose or xanthan gum, is a natural molecule composed of various sugars. It is obtained from potatoes, corn and peas, among others.
Native, untreated starch is not soluble in water at room temperature. Chemical modification yields a starch that is soluble in water (so-called cold-water soluble starch). The modified starch is used, among other things, in building material systems, where it controls water retention, or in starch adhesives.
Performance chemicals, in contrast to industrial chemicals, are products that have a more complex structure and where the focus is on an effect rather than the chemical structure.
In the case of rheological additives, for example, the control of the flow behaviour of a liquid is important; the chemical structure of the rheological additive is of secondary importance. For this reason, there are many different rheological additives that differ in chemical structure, such as cellulose ethers, xanthan gum, layered silicates, and fumed silica. Typical industrial chemicals include acids, lyes, salts and solvents such as alcohols.
Silicones is the name for a group of polymers whose basic structure consists of silicon and oxygen. The basic structure can be a linear chain, branched or forming a three-dimensional network. The raw material base for silicones is silica sand.
The silicon atoms still carry hydrocarbon residues, which gives silicones a position between organic and inorganic chemicals.
Silicones are also often referred to as siloxanes. If the hydrocarbon residues are methyl groups, the molecule is called polydimethylsiloxane (PDMS). The corresponding substance group is called silicone oil.
Silanes are bifunctional molecules that combine two properties.
The raw material base for silanes is silica sand. Silanes carry anchor groups with which they react with the surface of mineral substrates, glass or metals so that they sit firmly on this surface.
The second, the functional group, determines the properties that the silane brings to the surface. If the silane carries an alkyl rest as a functional group, the surface acquires water-repellent (hydrophobic) properties. If the functional group is, for example, an amine, an epoxide or carries a double bond, a subsequently applied coating can react with this functional group. This improves the adhesion of the coating to the substrate, and is also referred to as adhesion promoter.
Unlike mineral oils, silicone oils are based on silicon chemistry; the raw material base is silica sand. Silicone oils are more chemically resistant and also more resistant at high temperatures. They are used, for example, as lubricants, release agents, heat transfer oils and also as transformer oils.
Silicone emulsions are emulsions of silicone oil or of modified silicone oil. They are used wherever an aqueous dosage form is required, since silicone oils are only soluble in organic solvents.
Acids are among the important basic chemicals used in the chemical industry.
They are used in chemical processes, for example, to dissolve other substances and thus make them accessible for further conversion. But acids are also used in acid cleaners.
The best-known acids include sulphuric acid, hydrochloric acid, nitric acid and phosphoric acid, as well as organic acids such as formic acid, acetic acid and citric acid.
Many manufacturers of solid or liquid products do not have the production capacity or do not see it as their core business to dissolve solids in liquids, mix liquids or produce formulations. In individual cases, it may also be a matter of a new product of which it is not yet possible to judge whether it will be accepted by the market or for which a capacity expansion has not yet been implemented.
In all these cases, manufacturing is outsourced to contract blending service providers who specialise in producing appropriate blends quickly and to a high quality.
The BlendServ® department is the service provider for the production of blends within BCD Chemie.
Many plastics (synthetic polymers) are hard and brittle at room temperature. So-called plasticisers are used to make them more flexible and suitable for a wide range of applications. These are usually esters that dissolve in the plastic and improve the mobility of the individual polymer molecules in relation to one another – a molecular lubricant, so to speak.
Many manufacturers of solids or liquids do not have the ability to fill products into small or large containers – from 1-liter bottles, to 200-liter drums, IBCs, and even tank trucks. In such cases, in order not to have to invest in filling plants that are not utilized, the help of contract fillers of chemicalsis sought.
These service providers have various filling lines on which the products can be filled and labeled accordingly.
The BlendServ® department is the service provider for contract filling of chemicals within BCD Chemie.
The lacquer binder is the most important component of a coating or ink:
It forms a film on the surface after the coating or ink has been applied and dried and protects it or also serves decorative purposes, e.g. as a clear coating on wood, highlighting the wood structure, or by adding a colour when pigments are in the coating. The lacquer binder fixes the pigments to the surface, which could be brushed off the surface without the lacquer binder.
In principle, inks and coatings consist of four groups of substances:
The lacquer binder forms the coating film and protects the surface from environmental influences.
The second group of substances are the pigments, which give a coating its colour or are added for technical purposes such as corrosion protection. In the dried coating, the pigments are surrounded by the lacquer binder, which fixes them to the surface.
Additives for coatings improve the properties of the binder and are necessary to produce a high-performance coating.
The fourth group are the solvents, these can be organic solvents or water. They are necessary so that the coating can be well applied to the surface. The solvents then evaporate and the coating film with pigment and additives remains on the surface.
Additive for coatings include rheological additives to control flow behaviour and dispersing additives to keep pigments and fillers well suspended and prevent agglomeration of these solids. They also include antifoams, which on the one hand prevent the formation of foam and on the other hand destroy created foam that leaves an unsightly surface after the coating film has dried, wetting agents, which ensure good wetting of the surface, and adhesion promoters, which ensure good adhesion of the coating film to the surface.
To prevent plastics from immediately bursting into flames in the event of a fire, flame retardants are added to them. This contributes to safety: On the one hand, people in the room have more time to leave it, and on the other hand, emergency personnel have more time to rescue injured persons.
Depending on your requirements, foam may be desirable or undesirable. Desirable foam is, for example, in the beer glass, on the cappuccino, or else in foams consisting of cured PU foam, as in the case of mattresses.
However, foam is often undesirable in chemical or process engineering processes, as foam formation can cause a vessel to overflow or the overfill protection system to trip, interrupting production.
The formation of foam is also undesirable in inks and coatings, as it leads to an unsightly surface.
The liquid lamella, which encloses the air in the case of foam, is stabilized by surface-active substances such as surfactants. Antifoams are incompatible with the liquid to be defoamed and form small liquid droplets that migrate into the foam lamella and destroy it – the lamella bursts and the foam disappears.
To prevent pigments and other solids present in a solution from settling or clumping together, dispersing agents are used.
The dispersing agents accumulate on the surface of the solid and lead to a stable dispersion by electrostatic repulsion (surfaces carry like charges) or by steric stabilisation (space-filling molecular chains prevent the solids from approaching each other).
The raw material for cellulose ether is cellulose, which is obtained either from cotton linters or from wood. Cotton linters are particularly pure and consist of almost 100% cellulose. Coniferous wood is mostly used as wood pulp, as its wood fibers are longer than those of hardwood. Wood contains just under 50% cellulose, which must be separated from the accompanying substances (lignin). Pure cellulose is chemically modified to obtain cellulose ethers.
Cellulose ethers are, for example, methyl cellulose and carboxymethyl cellulose. They are used, among other things, as rheological additives in building inks as well as in building in cementitious plasters and tile adhesives as well as in gypsum systems. Only the use of cellulose ethers has made modern and easy-to-use high-quality plasters and tile adhesives possible.
Where possible, solvents in inks and coatings are replaced by water.
To function in water, different binders must be used than in solvent-based coatings. These binders are often already dispersed in water before they are formulated into a coating.
Amines find wide application in the chemical industry as building blocks for the synthesis of various products, but are also used in diverse processes, such
as catalysts in the production of PU foams.
They are also used for pH adjustment, corrosion protection in metal working fluids or gas scrubbing in refineries and power plants.
Amines are organic compounds that contain nitrogen (amino group). The numerous different amines often have an ammonia to fishy odour.
Rheological additives are used to control the flow behaviour of liquids or pastes.
They are more than simple thickeners that make a liquid more viscous: They can be used to selectively set different flow characteristics.
In paints, for example, the pigments must not settle during storage, which necessitates a high viscosity of the paint.
Storage stability is further enhanced by special dispersing additives, which contribute to better stabilization of the pigments. If the paint is applied, the viscosity should be lower so that it is easier to apply, subsequently flows and inconsistencies due to the brush stroke or roller pattern are avoided. In the end, the paint should be viscous again so that it does not run off on vertical surfaces.
Another example is greases: In these, oils are made so viscous by adding a rheological additive that they do not flow out of open systems (e.g. ball or roller bearings), as it would be the case with oils, for example.
The most important white pigment is titanium dioxide. Compared to other white pigments such as zinc oxide, barium sulfate or lithopone, it has a much higher refractive index and therefore appears whiter. Titanium dioxide is practically everywhere where products need to be white: in wall paints, in plastics, in high-quality papers, but also in toothpaste. Titanium dioxide is used in two different forms, as rutile and as anatase. Rutile is the slightly harder form, anatase the softer. The latter is used where abrasion plays a role.
