Type of Polyvinyl Butyral Resin Wash Primer

Polyvinyl butyral resin is used like on Vinilex 110 Active Primer that is based on butyral resin, anti corrosive (zinc chromate) pigment and phosphoric acid as a catalyst. It is a conventional etching primer in twin pack composition (base and catalyst) having good weather and solvent resistance. Adhesion to metal surfaces and subsequent paint, and anti - corrosion is good enough to be widely used as a wash primer of short exposure type for new plates pretreated in nonferrous metal, such as aluminum.

Polyvinyl Acetal/phenolic Application

Where adhesive is used in some highly important application such as in an aeroplane, durability is a subject of more than usual importance. Test made in Nigeria on aluminum alloy joints glued with an acetal/phenolic adhesive (not openly exposed to weather but exposed to the tropical atmosphere), have shown no drop in strength after nearly 5 years. And in America tests made over a wide range of climates have given generally satisfactory results, but with one or two anomalies, which is not uncommon experience in such testing.

Properties of Polyvinyl Acetal

The adhesive strength of polyvinyl acetal/phenolic adhesives cannot properly be considered without having regard to component ratio. It is, for example, commonly believed that increasing the acetal ratio (beyond some arbitrary limit) decreases tensile shear strength at elevated temperatures. To a certain extent this is true, but the presence of residual solvents, the inherent properties of the phenolic resin together with completeness of its cure, are other parameters that must be taken into consideration.

Polyvinyl Acetal/Phenolic Resin Adhesives

The term phenolic resin means a resin derived from formaldehyde and phenol itself. The most important polyvinyl acetals are the butyral and formal. The name polyvinyl acetal is more specifically applied to the product of reaction with acetaldehyde, but this acetal is not important as a component in two polymer adhesives.

Adhesives based on a mixture of a phenolic resin and polyvinyl formal or butyral were develop during the Second World War, the formal system largely in England as the method of bonding and the adhesive known as Redux, and the butyral system largely in America under three or four proprietary names.

Polyvinyl Chloride

Polyvinyl chloride is the most important vinyl halide, but appear to have been little used as an adhesive (not pressure sensitive) are recommended for bonding rigid PVC sheet and vinyl copolymer film to themselves and to polymethylmethacylate sheet.

In descriptions of the process used in making the so-called vinyl/steel laminates, detailed information about the adhesive is usually withheld, but in one paper the use of a vinyl chloride/synthetic rubber is mentioned, and adhesives containing polyvinyl chloride copolymers are referred to also in patent specifications.

Copolymers of vinyl chloride and vinyl isobytyl ether have use as adhesives, and polyisobuthylene, a polyolefine that (unlike polyethylene) is a facky semi solid in low molecular weight form, also has a place in certain hot melt compositions. Hot melt adhesive do not usually consist simply of one type of polymer, but of two or three, sometimes of different molecular weight for different uses, and often including also natural resins and waxes.

• Hot Melt Adhesives
• Polyvinyl alkyl ether
• Thermoplastic adhesive
• Polyethylene adhesive

Polyvinyl Alkyl Ethers

Polyvinyl alkyl ethers (some of which are elastomers although not generally classified as synthetic rubbers) are further examples of vinyl polymers having valuable adhesive properties. The monomers are prepared from acetylene and an alcohol in the presence of an alkali alcoholate. Polyvinyl ethyl ether, polyvinyl n-buthyl ether and polyvinyl isobutyl ether all range from extremely tacky semi solid to elastomeric solids, and therefore polymer blends can be made having properties that are appropriate to a wide range of adhesive applications. Polyvinyl methyl ether is a highly viscose liquid or a semi solid. The largest use of the polyvinyl ethers is in pressure sensitive adhesives. Polyvinyl stearyl ether is a waxy solid that is sometimes used as a modifier in adhesive compositions.

Polyvinyl Alcohol (PVA)

Polyvinyl Alcohol Adhesive

Many application is used of Polyvinyl Alcohol (PVA) as based material such as for glue or adhesive and for paint such as polyvinyl acetal adhesive. PVA more prefer use as glue than PVAc (Polyvinyl Acetate) because this adhesive relative have good smell than PVAc. The polymer of vinyl alcohol is made commercially by acid hydrolysis of polyvinyl acetate; the monomer has not been isolated. According to the degree of polymerisation and degree of hydrolysis, a wide range of polymers with molecular weight up to 200,000 may be prepared, having different solubility’s in water. With 70% acetate groups “polyvinyl alcohol” is insoluble in water, whereas with less than about 3 % it is soluble in hot water but may only swell in cold water, with about 12% acetate groups the polymer is completely soluble in both hot and cold water. The degree of hydrolysis is normally between 86% to 99%.

The limited resistance to water understandably restricts the usefulness of polyvinyl content are resistance to nearly all organic liquid, the polymers with a low acetate content are resistant to nearly all organic, liquids and consequently have an important place as adhesives in contact with greases and oils. It is possible to crosslink polyvinyl alcohol by heating with a small amount of a dicarboxylic acid and so increase its water resistance, but there appears to be no information available with respect to adhesive applications.

Polyvinyl Adhesive Use

Polyvinyl alcohol is probably the most widely used water soluble synthetic resin and its chief uses are in gluing porous materials such as kather cloth and paper. Being non-toxic and having no odour, polyvinyl alcohol is another polymer that is specially useful as an adhesive in contact with food.

Polyvinyl alcohol can be used as a re-moistenable adhesive because, although at high relative humid it absorbs water, the adhesive film does not become tacky unless it is wetted properly.

Unplasticized film which has been heated at 100oC for an hour will heat seal at 160 - 200 oC. It would seem, however, that is not very different from hot melt gluing. Glycerol and ethylene glycol are suitable plasticizers. Small amounts of polyvinyl alcohol are often incorporated in other aqueous adhesive composition in order to improve film forming properties or to increase adhesion.

Polyvinyl Acetal Adhesives

Polyvinyl acetal is the generic name of a group of polymers that are the product of reaction between polyvinyl alcohol and an aldehyde. In the preparation of these acetals polyvinyl acetate is used which in the course of the reaction is partially hydrolysed to the alcohol, thus the chain length of the acetate determine the chain length of the acetal. The monomer from of the vinyl acetals cannot be isolated.

Polyvinyl Acetate Adhesives

The vinyl group comprises the reactive part of a large number of compounds that produce thermoplastic polymers, most of which are extremely useful as adhesives. They include polyvinyl esters, ether and acetals, polyvinyl alcohol and polystyrene. Polyvinyl acetate itself often use in water treatment, even know in some countries already forbidden. In many application vinyl acetate can use for adhesive or as coating material like paint.

The most important polyvinyl ester adhesive is polyvinyl acetate (PVA). As an adhesive, it is used in solution, in aqueous dispersion, and by hot melt technique, in one form or another it is probably the most widely used thermoplastic adhesive.

Vinyl acetate is a flammable liquid made commercially from acetylene and acetic acid in the presence of a catalyst. As the molecular weight increases the polymer ranges from a soft to a hard solid, soluble mainly in polar organic solvents; adhesive solution are commonly made up in ketones, lower alcohols and esters. As the molecular weight reaches the order of 100,000 the polymer becomes soluble in toluene.

By the most important form in which the adhesive is used is the aqueous dispersion, made by the important industrial process known as emulsion polymerization, a process in which the liquid monomer is first emulsified in water and then polymerized by heating in the presence of a catalyst. Although loosely referred to as an emulsion, the product is not a liquid/liquid system, but mainly an aqueous dispersion of swollen solid particles. The advantage of an aqueous dispersion is not only that it uses water as the conveying medium, but also that a higher solids/viscosity ratio is possible than with a solution. Polyvinyl acetate solutions increase in viscosity as the molecular weight material is desirable because of its film strength, a solution that is fluid enough to permit easy application must necessarily be of low concentration. Emulsion polymerization overcomes this disadvantage because the molecular weight of the dispersed polymer has little effect on the viscosity can be easily produced. The particle size of the polymer should, however, cover as wide as a range as possible.

The well-known PVA emulsion glue, with a polymer content of about 50% is a versatile industrial adhesive. After application to an adherent water is eliminated from the emulsion through evaporation and absorption by absorbent adherent, and this result in the swollen particles coalescing to form a coherent adhesive film. For satisfactory coalescence and film formation, a certain amount of plasticiser must be incorporated, of which dibutyl phthalate and butyl carbitol acetate are an example. The plasticizer is largely responsible for the main shortcoming of polyvinyl acetate emulsion adhesives, the creep under stress which takes place especially at raised temperatures. Recognising the defect, some specifications include a creep test. If the testing of a glued joint the strength obtained is dependent on the rate of loading, especially if the glue has low resistance to creep.

Creep can be reduced by adding a urea formaldehyde to a PVA emulsion; such a product is dealt with. Certain copolymers of polyvinyl acetate such as an acrylate copolymer can be emulsified and their use generally result in a more versatile adhesive with lower creep. Many PVA emulsion glues are nowadays based on copolymers, at least in part. Creep can also be reduced by adding a vinyl methyl ether/maleic an hydride copolymer.

The thickening agents such as starches, starch-ethers, methyl cellulose or sodium carboxymethyl cellulose and also anti foaming compounds are frequently added to the emulsions. The incorporation of preservatives and other additives has been comprehensively dealt with. Polyvinyl alcohol is sometimes added; it is an effective stabiliser. Although room temperatures stability is normally good, an emulsion is likely to break if the temperature falls to the freezing point of the aqueous phase. The addition of 13-17% of high molecular weight ethylene oxide polymer (a water-soluble thermoplastic resin that has not found much use as an adhesive) enables a re-wettable (solvent activated) adhesive to be formulated, presumably a rather low molecular weight polyvinyl alcohol would do the same.

Certain polyvinyl acetate emulsion adhesive can be spray dried and marketed as dry powder that can be re-dispersed by simply mixing with water. Polyvinyl acetate is not only a good adhesive for a large number of porous or fibrous materials such as paper, wood and leather, but also far many nonporous materials especially transparent plastic films such as cellophane, cellulose esters, vinyl and polyethylene terephthalate. A rather different adhesive use is in making bonded fiber fabric.


An interesting application is the use of a PVA emulsion to increase the adhesion between old and new concrete. There are two ways in which this may be done, either by coating to old concrete before applying the new cement mix, or mixing a proportion of the PVA emulsion with the new mix.

Polyvinyl acetate emulsion are reasonably flexible; nevertheless, added flexibility for applications such as bookbinding can be obtained by incorporating compatible rubber latices.

These glues are non-toxic, clean and easy to use and rapidly assume a useful degree of strength especially with highly absorbent adherents. Their heat resistance is satisfactory up to 50^o – 60^oC. Gap filling is not usually good but the addition of thickening agents improves it. Tensile shear strength (at the normal rate of loading used in testing glued joints) has been shown with a variety of timbers to be comparable with urea and phenolic glues, while giving for reason that are not clear – consistently less wood failure.