Polyvinyl Butyral Resin (PVB) is a solvent Resin synthesized by the acetal reaction of Polyvinyl Alcohol (PVA) and butyraldehyde in contact with coal.
Because Pvb Resin itself contains a lot of hydroxyl groups, it can bridge with some thermosetting resins to improve the properties of chemicals and film hardness.
Because PVB resin has the above excellent characteristics, it is widely used in adhesive safety glass intermediate film of automobile and building, rust cutting primer, baking paint, wood paint, printing ink, adhesive of electronic ceramics and printed circuit board, adhesive between metal and metal, between metal and plastic, modifier of hot-melt adhesive, iron dimension waterproof processing of textile, etc. A variety of new industrial applications are also continuously developed and applied.
The general characteristics of PVB are as follows:
The appearance of polyvinyl butyral (PVB) resin is white spherical porous particles or powder, and its specific gravity is 1:1; However, the filling density is only 0.20 ~ 0.35g/ml.
Thermal properties
The glass transfer temperature (TG) of polyvinyl butyral (PVB) resin ranges from 50 ℃ of low degree of recombination to 90 ℃ of high degree of recombination; The glass transfer temperature can also be adjusted by adding an appropriate amount of Plasticizer to reduce it below 10 ℃.
Mechanical properties
The coating of polyvinyl butyral (PVB) resin has good water resistance, water resistance and oil resistance (it is resistant to aliphatic, mineral, animal and vegetable oils, but not to sesame oil). PVB is widely used in printing inks and coatings because it contains high hydroxyl groups and has good dispersibility to pigments.
In addition, its chemical structure contains both hydrophobic acetal and acetic ACID groups and hydrophilic hydroxyl groups, so PVB has good adhesion to glass, metal, plastic, leather and wood.
Chemical reaction
Any chemical that can react with secondary alcohol will also react with PVB. Therefore, in many applications of PVB, it is often used with thermosetting resin to bridge and harden with the hydroxyl group of PVB, so as to achieve the characteristics of chemical resistance, solvent resistance and water resistance.
Of course, films with different characteristics (such as hardness, toughness, impact resistance, etc.) can be prepared according to different types of thermosetting resin and different mixing ratio with PVB.
Safety properties
In the meantime, the chemical factories of Continental Europe, principally in Germany, Austria and Belgium, had taken hold of the novelty and under the collective name of lithopone or lithophone, by numerous processes, produced various grades of the pigment, branding the respective qualities as red seal, green seal, yellow seal, blue seal, etc., or selling them under some fancy name. Of this we shall speak later on. The crusade against the use of white lead in the various countries of Continental Europe, assisted the manufacturers, to a very great extent, in marketing their products, not only to industrial concerns, as has been the case in this country, until recently, but to the general painting trade. Up to 1889 the imports into this country were comparatively small. At that time one of the largest concerns manufacturing oilcloth and linoleum in the State of New Jersey began to import and use Charlton white. Shortly after that other oilcloth manufacturers followed suit, replacing zinc white with lithopone in the making of white tablecloth, etc., and later on abandoning the use of white lead in floor cloth and linoleum. This gave an impetus to several chemical concerns, that erected plants and began to manufacture the pigment. Competition among the manufacturers and the activity of the importers induced other industries to experiment with lithopone, and the shade cloth makers, who formerly used white lead chiefly, are now among the largest consumers. Makers of India rubber goods, implement makers and paint manufacturers are also consumers of great quantities, and the demand is very much on the increase, as the nature of the pigment is becoming better understood and its defects brought under control. Large quantities find their way into floor paints, machinery paints, implement paints and enamel paints, while the flat wall paints that have of late come into such extensive use owe their existence to the use of lithopone in their makeup.