Solvent degreasing

Despite environmental pressures to move away from solvent degreasing systems many plants find solvents to be the easiest to use. 

Of the solvent systems, trichloroethylene is the most efficient. The inserts are first tumbled in the solvent to remove the majority of the organic contaminants. To obtain a surface that is free from oils and grease, a vapour phase degrease is then used. When the inserts are flooded with vapour, the solvent immediately begins to condense on the insert surface and then run off, carrying with it in solution the last traces of organic contaminants. The volume of condensate, per insert, depends on  

The process is complete once the insert temperature reaches that of the vapour when there is no further condensation. 

It should be noted that finely divided aluminium and magnesium alloy dust, produced when tumbling castings and machined components of the metals, can react with halogenated solvents with considerable violence. Grades of trichloroethylene are available that are stabilised for use with aluminium. 

When aluminium is delivered to the plant in a clean state there is no need for a degreasing step. 

The solubility of Aerosol OT Surfactant is extremely high in all solvents used for degreasing. It will dissolve easily at room temperature in most cases. If heating is required for solubilization, the solution will be stable upon return to room temperature. 

As an example, Aerosol OT-75% is soluble to over 50% at room temperature in carbon tetrachloride, but naphtha solvent requires heating. Both are clear solutions at room temperature. The presence of the water in Aerosol OT-75% portion is an aid in the removal of any watei—soluble particles present in the work being degreased. 

This type of cleaner can be sprayed on, brushed on, or the work can be immersed into it followed by a rinse. 

To remove heavy lubricating and preservative oils and greases, many solvents may be used to specific needs. Aerosol GPG Surfactant will be found to be soluble in all of these solvents. A typical formulation used is  

Preparation is by simple mixing. Tri- or tetrachloroethylene, high flash naphtha or other suitable solvents can be substituted for the kerosene. 

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Other techniques aimed at improving grease recovery (and often attempting also to improve the scouring process itself) have included solvent degreasing of the wool (52,53), solvent extraction of the Hquor or sludge (178), aeration (179,180), and physical and chemical destabilization (175). 

Nonaqueous solvent degreasers tend to work as cold degreasers, but where considerable quantities of grease must be removed, aqueous-based emulsifying degreasers are employed, and these work best in hot water or steam solution. 

Glue Rubber and PVC cemenr Cleaning solvents Degreaser Spot remover Dry cleaning fluid Halothane... 

Solvent degreasing Vapors perchloroethylene, trichlorethylene, vapor decomposition (e.g., phosgene)... 

Uses Solvent for cellulose esters and resins in manufacturing of printing inks, nail polishes, polymerization and spinning of acrylonitrile, dyeing wool, polyvinyl chloride adhesives, esters, waxes, vegetable oils brake fluids solvent degreasing antiseptic organic synthesis. 

Uses Solvent degreaser paint and varnish removers. 

Methyl ethyl ketone Common solvent used in the manufacture of coatings, solvents, degreasing agents, lacquers, resins and smokeless powders. 

Xylene (dimethylbenzene) has been substituted for benzene in many solvent degreasing operations. Like toluene, the three xylenes do not possess the myelotoxic properties of benzene, nor have they been associated with leukemia. Xylene is a central nervous system depressant and a skin irritant. Less refined grades of xylene contain benzene. See Table 56-1 for the TLVs. 

There are numerous metal pretreatment techniques that can be used in addition to solvent degreasing. To obtain metal/polymer systems which exhibit strong initial adhesion it is usually sufficient to wash the metal with a solvent followed by an acid etch or sandblasting technique to remove any weak oxide layers and roughen the surface simultaneously. 

These agents find wide use as industrial solvents, degreasing agents, and cleaning agents. The substances include carbon tetrachloride, chloroform, trichloroethylene, tetrachloroethylene (perchloroethylene), and 1,1,1-trichloroethane (methyl chloroform). See Table 57-1 for recommended threshold limit values. 

Degradation of agrochemicals, solvents, degreasers, flame retardants, and chemical intermediates used in the production of high volume chemicals [113] detoxification of chlorophenols [61] Transformation of pesticides including phenylcarbamates (e.g., CIPC, IPQ and organophosphates (e.g., malathion, paraoxon, parathion) [53]... 

Solvent degreasers Fatty alcohol ethoxylates EO/PO co-polymers Amine ethoxylates Polyglycol esters Emulsifiers... 

Polyphenylene sulfide parts are commonly bonded together with adhesives. A suggested surface preparation method is to solvent-degrease the substrate in acetone, sandblast, and then repeat the degreasing step with fresh solvent. The polyphenylene sulfide surface that forms next to a mold surface is more difficult to bond than a freshly abraided surface. This is possibly due to a different chemical surface structure that forms at high temperature when the resin is in contact with the metal mold surface. 

Medium- to high-strength bonds, suitable for noncritical applications Optimum bond strength per FPL etch process. Specified in ASTM D 2651 and MIL-A-9067. Solvent degrease may replace alkaline cleaning. 

Chromium Trichloroethylene 1. Abrasion. Grit or vapor blast, or 100-grit emery cloth, followed by solvent degreasing. 2. Etch for 1-5 min at 90-95°C in Suitable for general-purpose bonding For maximum bond strength... 

Solvent-degrease. Immerse 30 s at RT in For copper alloys containing over 95% copper. 

Solvent-degrease in nitric acid solution as in item 5 ASTM D 2651 nitric acid-sodium chlorite etch,... 

Nickel T richloroethylene 1. Abrasion with 100-grit emery cloth followed by solvent degreasing. 2. Etch for 5 s at 20°C in nitric acid (69%). Wash in cold and hot water followed by a distilled water rinse and air-dry at 40°C. For general-purpose bonding For general-purpose bonding... 

Silver T richloroethylene Abrasion with 320-grit emery cloth followed by solvent degreasing. ... 

Abrasion with 100-grit emery cloth, grit or vapor blast, followed by solvent degreasing. 

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