Plastic mesh tells about the characteristics of PVB

Polyvinyl butyral resin, abbreviated as PVB , is a solvent-based resin. PVB has good film-forming properties, and the film formed by PVB has excellent properties such as high transparency, elasticity, toughness, strength, oil resistance, flexibility and low-temperature impact resistance, and PVB has a special chemical structure, so It has excellent adhesion to glass, metal, ceramic powder, plastic, leather and wood. It also has good dispersibility for pigments and dyes and good compatibility with other resins. Because the PVB resin itself contains a large proportion of hydroxyl groups, it can be bridged with some thermosetting resins to improve the properties of chemicals and film hardness. Because PVB resin has various excellent properties as described above, it is widely used as an adhesive for safety glass interlayer film, rust primer, baking varnish, wood lacquer, printing ink, electronic ceramic and printed circuit board for automobiles and buildings. , metal and metal, metal and plastic between the adhesive, hot melt adhesive modifier, textile iron waterproof processing. New uses in various industries are also being continuously developed and applied.
PVB characteristics
General characteristics
The appearance of polyvinyl butyral (PVB) resin is a white spherical porous particle or powder having a specific gravity of 1:1; however, the packing density is only 0.20 to 0.35 g/ml.
Thermal property
The glass transition temperature (Tg) of polyvinyl butyral (PVB) resin is from 50 ° C with low coincidence to 90 ° C with high degree of coincidence; this glass transition temperature can also be adjusted by adding an appropriate amount of plasticizer. Drop below 10 °C.
Mechanical properties
The coating film of polyvinyl butyral (PVB) resin has good water resistance, resistance and oil resistance (resistance to aliphatic, mineral, animal and vegetable oils, but not to castor oil). Because PVB contains high hydroxyl groups and good dispersibility to pigments, it is widely used in printing inks and coatings. In addition, its chemical structure contains both hydrophobic acetal and acetate groups and hydrophilic hydroxyl groups, so PVB and glass, metal, plastic, leather and wood have good adhesion.
Chemical reaction properties
Any chemical that reacts with the secondary alcohol also reacts with PVB. Therefore, in many PVB applications, it is often used with a thermosetting resin to bridge the hardening of the hydroxyl group of PVB. To achieve chemical resistance, solvent resistance and water resistance. Of course, depending on the type of thermosetting resin and the mixing ratio with PVB, a coating film having different characteristics (such as hardness, toughness, impact resistance, etc.) can be added.
Safety nature
Pure PVB is non-toxic and harmless to the human body. In addition, ethyl acetate or alcohol can be used as a solvent, so PVB is widely used in printing containers for food containers and plastic packaging in Europe and the United States.
Storage
As long as PVB is not in direct contact with water, it can be stored for two years without affecting its quality. PVB should be stored in a dry and cool place, and avoid direct sunlight. Avoid heavy pressure when storing PVB.
Dissolution characteristics
PVB is soluble in solvents such as alcohols, ketones, and esters, and the solubility in various solvents varies depending on the composition of the functional groups of PVB itself. In general, alcohol solvents are easily soluble, but methanol is more difficult to dissolve in high acetal groups; the higher the acetal group, the easier it is to dissolve in ketone solvents and ester solvents; PVB is easily soluble in alcohol ethers. Solvent; PVB is only partially dissolved in aromatic solvents such as xylene and toluene; PVB is not dissolved in hydrocarbon solvents.
Viscosity characteristics of PVB solution
The viscosity of the PVB solution is greatly affected by the formulation of the solvent and the type of the solvent; in general, if the alcohol is used as the solvent, the higher the molecular weight of the alcohol, the higher the viscosity of the PVB solution; the aromatics such as xylene and toluene. Solvents and hydrocarbon solvents can be used as diluents to reduce the viscosity of PVB solutions; the effect of PVB chemical composition on viscosity is summarized as follows: in the same solvent, the same content of each group, the higher the degree of polymerization, the higher the viscosity of the solution; in the same solvent Under the same degree of polymerization, the higher the acetal or acetate group, the lower the viscosity of the solution.

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