Ethyl silicate binders

Commercial products containing ethyl silicate binders include Dynasil and Silester (Hills), Ethylsilicate (Union Carbide), Ethylsilikat (Wacker), Silbond (Akzo). 

Ethyl silicate binders are mainly used in applications involving high temperatures and corrosive influences. The principal application of ethyl silicate zinc dust coatings is the protection of iron and steel against corrosion it is effective even at temperatures of up to 400 C. Examples include ships, harbor construction work, bridges, steel structures exposed to atmospheres in industrial areas, tanks, containers, pipelines, and chimneys. 

Silicate binders are used in conjunction with zinc powder to give paints of excellent corrosion resistance. The organo-silicates, e.g. ethyl orthosilicate, are most commonly used. The full potential of this type of binder has probably not yet been exploited. 

Inorganic zinc-rich primers consist of zinc and a reactive binder such as an alkali metal silicate (sodium, potassium, lithium or quaternary ammonium silicate) or hydrolyzed ethyl silicate as binder. On mixing hard and cohesive films of silicate are formed. The structure of the inorganic zinc-rich silicate may appear as shown in Figure 1.66. 

Into a beaker place 90 grams of the binder material, Sylgard TM, which is an ethyl silicate resin, and then add 510 grams of HMX and thoroughly mix for 5 hour until a homogeneous mixture results. After mixing for 1 hour, vibrate the beaker for 1 hour to remove air bubbles, and then cast the explosive into any desirable mold or container and then dry for 24 hours in an oven at 50 Celsius. After 24 hours, remove the explosive from the oven, and then remove the explosive from its mold or container. The explosive is then ready to be used. Requires blasting cap or detonator for initiation. Commercial Industrial... 

Zinc dust coatings are utilized in large quantities for the protection of structural steel, also including underwater steel construction and ship building [5.56]. Zinc dust is used in organic and inorganic binder systems (alkali silicates, ethyl silicates) [5.56, 5.105]. 

In practice the ester is mixed with the required amount of water and a suitable solvent (e.g., alcohols, esters, ketones). To obtain 100 Vo hydrolysis of 1 mol of an orthosilicate, 2 mol of water must be added. By maintaining a constant pH (for ethyl silicate ca. 2) the condensation reaction can be suppressed to such an extent that hydrolyzates of ethyl silicate containing 20% SiOj and with a degree of hydrolysis of 80-90% remain stable for about one year. If this equilibrium is disturbed (e.g., by shifting the pH value or evaporating the solvent), condensation commences and the solution solidifies after a short time. This mechanism is used in two-pack zinc dust paints. In the simplest case the binder is a hydrolyzate in alcoholic solution. Zinc dust and, if necessary, extenders, antisettling agents, colorants, etc. are then added. Addition of zinc consumes acid and the pH value increases. 

Historical Development. The importance and advantages of ethyl silicate zinc dust paints were recognized and intensively investigated in the late 1940s [2.187], [2.188]. The fundamental work of Lopata and Keithler [2.189] on the partial acid hydrolysis of tetraethyl orthosilicate and the use of the product as a zinc dust paint binder was followed by attempts to improve the application properties and quality of the coatings (e.g., by adding polyfvinyl butyral) [2.190], alkyl titanates [2.191], borate esters [2.192], or trialkyl phosphates [2.19. ]. 

Ethyl silicate was transesterified with higher alcohols to produce binders with a higher flash point [2.194], [2.195],... 

Continuous efforts have therefore been made to develop binders for one-pack paints which must be completely compatible with active pigments such as zinc dust. Mixtures of ethyl silicate and zinc can be stored for unlimited periods in the absence of water. If the hydrolysis and condensation reactions caused by atmospheric moisture can be sufficiently accelerated during application of the coating, a one-pack system can be produced. 

All binders formed from ethyl silicate have a relatively low flash point due to the ethanol released during hydrolysis (flash point of ethanol 12 C). The paint may have a somewhat higher flash point (15 C) because its ethanol content is low. The use of higher alkyl groups yields systems with higher Hash points. 

Production. On account of the many possible variations in batch formulation and production procedure, only a general outline and instructions for producing one-and two-pack binders from ethyl silicate can be given here. The following batch formulation (in parts by weight) is typical for a two-pack binder containing 20 wt% SiOj ethyl polysilicate 500, solvents 440, and 1 % hydrochloric acid 60. Alcohols such as ethanol and 2-propanol, often mixed with one another and with ketones, ethers, and esters, are used as solvents. 

The solvents, dilute hydrochloric acid, and ethyl silicate are mixed and stirred and the temperature rises an upper limit of 25-30 C is often recommended. The second component of the two-pack paint is the pigment-extender mixture. The binder can be used after 1 - 3 d the storage stability is limited and is generally specified by the manufacturer. In the above example it is ca. one year. 

Ethyl silicate zinc dust paints can be covered with many conventional topcoat systems [2.196]. This is necessary in an acid or alkaline environment to prevent the zinc from being attacked. Ethyl silicate is also suitable as a binder for inorganic pigments on account of its UV resistance. 

The liquid ceramic slurry consists of a binder and a very fine refractory powder, reduced to slime by permanent mixing. The binder may be colloidal silica, hydrolysed ethyl silicate or hydrolysed sodium silicate, the choice of the technology applied being determined by technical reasons. When using ethyl silicate, drying is faster, which allows a higher cycle rate, but ethyl alcohol vapours are emitted. These vapours, if present in too large an amount, have to be collected and treated before emission. 

SILIKOFTAL ED binder, optical fiber coatings Actllane 230HD30 binder, org. solvent systems Ethyl hydroxyethyl ceUilose binder, outdoor paints Potassium silicate binder, oven anticorrosive paints SILIKOPHEN P 60/D SiLiKOPHEN P 65/W SiLiKOPHEN P 70/MPA SILIKOPHEN P 80/20 SILIKOPHEN ... 

Ethyl silicote is o woter-white liquid, soluble in alcohol. It hydrolyzes In water to an adhesive form of silicic acid and alcohol. It is used in lacquers and paint as a pigment binder giving films that are resistant to fire and chemicals and are weatherproof. A less pure, higher silica ester, Ethyl Silicate 40, is also available commerciolly. 

Glyceryl behenate Hydrogenated cottonseed oil Hydrogenated palm oil binder, carbon arc-light electrodes Potassium silicate binder, carpet backing Styrene/butadiene polymer binder, catalysts Silica, colloidal binder, caulks Vinyl acrylic copolymer binder, cement Polyacrylamide Sulfur binder, cementitious surfaces Potassium silicate binder, ceramic Ethylene/MA copolymer binder, ceramic fibers Silica, colloidal binder, ceramic glazes Hydroxyethylcellulose Methylcellulose binder, ceramic paste Ethyl silicate... 

Dimethylaminoethyl methacrylate Ethyl silicate Gum ghatti Polyacrylamide Potassium oxidized microcrystalline wax PVM/MA copolymer, isopropyl ester Styrene/butadlene polymer Urea-formaldehyde resin binder, coatings board coatings Vinyl acrylate... 

PVM/MA copolymer, isopropyl ester binder, glass fibers Styrene/PVP copolymer Vinyl acetate/ethylene/vinyl chloride terpolymer Vinyl chloride/vinyl acetate copolymer binder, glass treatment PEG-5M PEG-9M PEG-23M PEG-45M binder, gravure printing inks Ethyl hydroxyethyl cellulose binder, grinding wheels PEG-2 stearate binder, grindstones Sodium silicate binder, hair care... 

Hydrolyzed casein Hydrolyzed milk protein binder, nylon Epoxy-novolac binder, oil cosmetics Hydrolyzed rice protein binder, oil hair care Hydrolyzed rice protein binder, oil oil-absorbent formulations Hydrolyzed rice protein binder, oil skin care Hydrolyzed rice protein binder, oil-well sands Phenol-formaldehyde resin Phenolic resin binder, organic solvent systems Ethyl hydroxyethyl cellulose binder, outdoor paints Potassium silicate binder, paints... 

Ethyl silicate Potassium silicate binder, printing foil... 

Immersion test in 0.1 M sodium chloride solution allowed to observe, particularly in those panels with X-cut, that coatings based on nano-structured film-forming material as binder showed greater amount of white products from corrosion of metallic zinc than in those panels protected with primers made with partially hydrolyzed ethyl silicate as binder. This performance would be supported in the less zinc dispersion ability that displays the first binder, which would generate films more porous. 

The electrode potential measurements as a function of immersion time indicates that both types of binders had a significant influence on the electrode potential in general, more negative values were obtained with nano-structured film-forming materials, which means that the primers based on lithium silicate showed better cathodic protection than those manufactured with ethyl silicate. 

Hoshyargar, F. Ali Sherafati, S. and Hashemi, M (2009). Short communication A new study on binder performance and formulation modification of anti-corrosive primer based on ethyl silicate resin Progress in Organic Coatings, Vol. 65, No. 3, 0uly 2009), pp. 410-413, DOI 10.1016/j.porgcoat.2009.02.006... 

Nitro paraffin (explosives) binder Methyl vinyl Refractory mold (silicates) binder Methyl vinyl Azide and hydrazine binders— Ethyl vinyl rocket propellent binder... 

These are solvent born alkyl silicates coatings in which zinc is incorporated. The binders are mostly modified alkyl silicates consisting of partially hydrolyzed silicates (generally ethyl-silicate type). 

The pattern is made by pouring or injecting wax into a metal mould. In some cases a simple pattern may be prodnced in one step with an integral gating system, while in other cases complex patterns may be assembled from a nnmber of separate components prepared individually. In the ceramic shell process, after the wax pattern is formed it is dip-coated with a primary slurry coat of very fine particles to give a smooth surface it is then stuccoed with coarser refractory and dried. These steps are repeated until the required mould thickness is achieved. The primary and secondary dip-coats contain binders such as ethyl silicate, and the refractories are principally zircon, sillimanite... 

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