Polyvinyl butyrate

Fig. S-6 Relation between the density of cathodic blisters and potential shot-peened steel sheet without primer ( ) and with about 40 /tm primer coat (Zn ethyl silicate + polyvinyl butyral) ( ) top coat 500 /tm EP-tar ...

Group of plastics composed of resins derived from vinyl monomers, excluding those that are covered by other classifications (i.e., acrylics and styrene plastics). Examples include PVC, polyvinyl acetate, polyvinyl butyral, and various... 

Cellulose Esters Epoxy Resins Lignins Polystyrene Poly (2-vinyl pyridine) Polyvinyl Chloride Polymethyl methacrylate Polyphenylene Oxide Phenolics Polycarbonate Polyvinyl Acetate, etc. Polyvinyl butyral SBR rubber, etc., etc. 

The purity of the zinc is unimportant, within wide limits, in determining its life, which is roughly proportional to thickness under any given set of exposure conditions. In the more heavily polluted industrial areas the best results are obtained if zinc is protected by painting, and nowadays there are many suitable primers and painting schemes which can be used to give an extremely useful and long service life under atmospheric corrosion conditions. Primers in common use are calcium plumbate, metallic lead, zinc phosphate and etch primers based on polyvinyl butyral. The latter have proved particularly useful in marine environments, especially under zinc chromate primers . 

A low acid polyvinyl butyral-based pretreatment primer ( etch or wash primer are alternative names) is usually advantageous as the first treatment of a metal-sprayed surface before painting. Up to an equal volume of spirit soluble phenolic resin is used as a diluent to the polyvinyl butyral of conventional pretreatment primers. This has an incidental, but particularly valuable effect, in reducing the free acid available to penetrate into the pores of the coating. The modified pretreatment primer is highly water resistant and this helps to avoid damage due to condensation. 

Etch primers are widely used. They are mostly based on polyvinyl butyral and contain chromates and phosphoric acid. They are said to act both as primers and as etching solutions because it is believed that the chromates and phosphoric acid form an inorganic him, which provides adhesion, while oxidised polyvinyl butyral provides an organic him. For direct application to new galvanised steel, the best known primers are based on calcium orthoplumbate pigment and metallic lead, but these are now less used for environmental reasons. Zinc-dust paints and zinc-phosphate pigmented paints are also used, but the trend is to use pretreatments to assure good adhesion. 

A characteristic of the group (a) of resins is that they air-dry solely by solvent evaporation and remain permanently solvent soluble. This fact, combined with the need to use strong solvents, makes brush application very difficult, but sprayed coats can be applied at intervals of one hour. A full vinyl system such as (o) possesses excellent chemical and water resistance. Many members of group (o) have very poor adhesion to metal, and have therefore been exploited as strip lacquers for temporary protection. Excellent adhesion is, however, obtained by initial application of an etching primer the best known of such primers comprises polyvinyl butyral, zinc tetroxy-chromate and phosphoric acid. 

Etch primers partially fulfil the roles of both pretreatment and primer. They contain phosphoric acid for surface passivation and are based on polyvinyl butyral ... 

The standard etch primer (WP-1, DEF-1408) consists of two solutions, one containing polyvinyl butyral resin and zinc tetroxychromate in ethyl alcohol with n-butanol, and the second containing phosphoric acid and ethyl alcohol. It is essential that a small critical amount of water be present in the latter. The two solutions are mixed in appropriate ratio for use the mixture deteriorates and should be discarded when more than 8 h old. Single-pack etch primers of reasonable shelf life are available but contain less phosphoric acid than the above and are not considered to be so effective. 

Polyvinyl acetate and derivatives Polyvinyl acetate is used largely for coating applications, but the derivative polyvinyl alcohol, will, providing there are some residual acetate groups, dissolve in water. Reaction products of polyvinyl alcohol with aldehydes such as polyvinyl formal and polyvinyl butyral are highly specialised materials. 

Binder Nomenclature Identification a - Polyvinyl butyral resin - Monsanto Co b - Hexafluoropropylene/vinylidme. fluoride 1 2 c - Polyurethane so in system — B.F. Goodrich Co d - Polytrifluorochloroethylene - 3M Co... 

Polyvinyl alcohol Polyvinyl butyral Polyvinyl chloride... 

Poly Vinyl ACetate Poly Vinyl ALcohol PolyVinyl Butyrate Poly Vinyl Chloride PolyVinyliDene Chloride Chlorinated PVC Unplasticized PVC... 

Uses Solvent for nitrocellulose, ethyl cellulose, polyvinyl butyral, rosin, shellac, manila resin, dyes fuel for utility plants home heating oil extender preparation of methyl esters, formaldehyde, methacrylates, methylamines, dimethyl terephthalate, polyformaldehydes methyl halides, ethylene glycol in gasoline and diesel oil antifreezes octane booster in gasoline source of hydrocarbon for fuel cells extractant for animal and vegetable oils denaturant for ethanol in formaldehyde solutions to inhibit polymerization softening agent for certain plastics dehydrator for natural gas intermediate in production of methyl terLbutyl ether. 

Another attractive quality of the PVA is its outstanding chemical stability. Peter and Stefan ( ) investigated the chemical stability of PVA vis a vis a series of solvents and reagents and some of their results are summarized in Table I. This table presents a comparison between the chemical resistances of PVA, polyvinyl butyral(PVB), polyvinyl acetate(PVAc), and cellulose acetate(CA). It is evident from this table that the PVA is considerably more stable than the rest of the tested materials. 

Screen Preparations, 100 micron thick x-ray intensifying screens were prepared using standard doctor blade coating techniques. The final phosphor volume was 50% when the coatings were dried. In most instances, the phosphor suspensions were prepared using polyvinyl butyral binders with viscosities adjusted to 2000 centipoise for the doctor blade operation and care was taken to avoid convection cell formation (9). A cross section of the screen construction is shown in Figure I. The completed screens consist of polyester (Mylar) base about 10 mil. thick, a 50 micron thick (TI02 (rutile) reflector layer, a 100 micron thick phosphor layer, a 10 micron thick clear cellulose acetate butyrate top protective layer. 

Hie annual worldwide production of plastidzers is over 3 million tons, and the U.S. production is in excess of 1 million tons. In fact, plastidzers are major components of a number of polymer-containing products. For instance, the liner in automobile safety glass is composed mainly of polyvinyl butyral containing about 30% plastidzer. 

Polytetrafluoroethylene Teflon Polyurethane Polyvinyl alcohol Polyvinyl acetate Polyvinyl butyral Polyvinyl chloride Polyvinylidene chloride Polyvinylidene fluoride... 

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