Powder varnish

IKP University of Stuttgart (1992-1995) Life cycle engineering of powder varnish technique, comparison with other varnish technologies, funded by BMBF... 

Despite the introduction of water based and powder varnishes, cellulose nitrate varnishes with their high solvent content, are still widely used due to their easy application and their low prices. The current varnish application still requires the use of solvents. The chosen coating procedure determines the necessary processing viscosity, which may be adjusted in different ways ... 

Polyimides (PI) were among the eadiest candidates in the field of thermally stable polymers. In addition to high temperature property retention, these materials also exhibit chemical resistance and relative ease of synthesis and use. This has led to numerous innovations in the chemistry of synthesis and cure mechanisms, stmcture variations, and ultimately products and appHcations. Polyimides (qv) are available as films, fibers, enamels or varnishes, adhesives, matrix resins for composites, and mol ding powders. They are used in numerous commercial and military aircraft as stmctural composites, eg, over a ton of polyimide film is presently used on the NASA shuttle orbiter. Work continues on these materials, including the more recent electronic apphcations. 

Thin coatings consist of paints and varnishes, which are applied as liquids or powdered resin with a thickness of about 0.5 mm [e.g., epoxy resin (EP) [2]]. Typical thick coatings are bituminous materials [3] and polyolefins [e.g., polyethylene (PE) [4]], thick coating resin combinations [e.g., EP tar and polyurethane (PUR) tar [2]] as well as heat-shrinkable sleeves and tape systems [5]. 

Meanwhile, cellulose acetates were intensively studied to produce triacetate, a waterproof varnish to the fabric on World War I airplane wings. Triacetate also was made in powdered (omi for later melting and molding. With manufacturing development of methylene chloride, triacetate film came into use as a photographic base in 1935. Transparent acetate film was developed, and used for packaging. 

AsphalNkitt, m. asphalt cement, asphalt mastic, lack, m. asphalt varnish, mastiz, rn. Asphaltkitt. -mehl, n. asphalt powder, papier, n. asphalt paper. pappe, /. asphalt board, pech, n. bituminous pitch, pflaster,... 

Bronze-giesserei, /. bronze foundry bronze founding, -glanz, tn. bronze luster, -guss, tn. bronze casting, cast bronze, -lack, tn. bronze varnish, bronzing lacquer, -pulver, n. bronze powder, -tinktur, /. bronzing liquid. 

Sikkativ, n. siccative, drier, -firms, m. sicca tive varnish, -mittel, n. siccative, drier, -pulver, n. drying powder, specif, manganese borate. 

Uses Manufacture of smokeless powder, photographic film and plates, artificial leather and silk, perfumes pharmaceuticals in cleaning textiles solvent for nitrocellulose, lacquers, varnishes, and airplane dopes ingredient in artificial fruit essences. 

Uses of EtCell include films, adhesive, flexible lacquers, varnishes-, plastics, electrical insulators, moulding powders, jelled expls such as used in Bangalore Torpedo (See Vol 2, pp B16 ff), inhibitor tape for rockets and proximity fuzes (Refs 8 10)... 

Shellac, boiled linseed oil, resins, paraffin wax, beeswax, litbographic varnish and acaroid resin are used in various pyrotechnic formulations. Similarly chlorinated rubber powder has also been used successfully as a binder. Some of tbe waxes and resins which are of natural origin are still popular and are in use. In order to improve quahty and avoid batch-to-batch variation, manufacturers of pyrotechnics are moving from natural binders to man-made binders. 

Whatever its behaviour in sunlight, powder should not be exposed to direct sunshine at any stage of manufacture all the windows of the plant should face north and any that do not should be covered with a layer of blue or yellow varnish, to cut off the rays of shorter wavelength. 

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