Pure PVB is non-toxic and harmless to human body. In addition, ethyl acetate or alcohol can be used as solvent, so PVB is widely used in printing ink of food containers and plastic packaging in European and American countries.
Storage safety properties
PVB can be stored for two years without affecting its quality as long as it is not in direct contact with water; PVB shall be stored in a dry and cool place and avoid direct sunlight. Heavy pressure shall be avoided during PVB storage.
Solubility
PVB is soluble in alcohol, ketone, ester and other solvents. The solubility of various solvents changes according to the functional group composition of PVB itself. Generally speaking, alcohol solvents are soluble, but methanol is more insoluble for those with 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 cellosolve solvents; PVB is only partially dissolved in aromatic solvents such as xylene and toluene; PVB is insoluble in hydrocarbon solvents.
Viscosity characteristics of PVB solution
The viscosity of PVB solution is greatly affected by the formula of solvent and the type of solvent; Generally speaking, if alcohol is used as solvent, the higher the molecular weight of alcohol, the higher the viscosity of PVB solution;
Aromatic solvents such as xylene and toluene and hydrocarbon solvents can be used as diluents to reduce the viscosity of PVB solution; The effect of PVB chemical composition on viscosity is summarized as follows: under the same solvent and the same content of each base, the higher the degree of polymerization, the higher the solution viscosity; Under the same solvent and the same degree of polymerization, the higher the acetal group or acetate group, the lower the solution viscosity.
Dissolution method of PVB
Where mixed solvents are used, the dissolution step is to first put aromatic solvents (such as xylene, toluene, etc.) or ester solvents (such as n-butyl acetate, ethyl acetate, etc.) into the mixing, slowly put PVB into the mixing, and then add alcohol solvents (such as n-butanol, ethanol, etc.) after PVB is dispersed and expanded,
At this time, the dissolution time can be shortened by heating; Using this dissolution method, the formation of lumpy PVB can be avoided (because the dissolution time will be several times after the formation of lumpy PVB), so the dissolution speed can be accelerated. Generally, the ratio of aromatic and alcohol solvents is 60 / 40 ~ 40 / 60 (weight ratio), and PVB solution with low viscosity can be prepared.
The solvent composition contains 2 ~ 3wt% water, which can improve the hydrogen bonding strength of alcohol solvents and help the solubility of PVB.
Processing properties
Although PVB resin is a thermoplastic, it has little processability before plasticizer is added. Once plasticizer is added, its processability is very easy.
The purpose of general coatings and adhesives is to change the resin characteristics by adding plasticizers to meet the application requirements, such as film softness, reducing the TG point of the resin, reducing the heat sealing temperature, maintaining low-temperature softness, etc.
Compatibility
PVB can be compatible with a variety of resins, such as phenolic resin, epoxy resin, alkyd resin and MELAMINE resin.
B-08sy, b-06sy and b-05sy with high acetal degree can be mixed with nitrocellulose in any proportion. PVB and alkyd resin are partially compatible. General PVB is compatible with low molecular weight epoxy resin, while high molecular weight epoxy resin needs PVB with high acetal degree to be compatible with each other.
Polyvinyl butyral (PVB) is dissolved into 12 ~ 14% solution with ethanol and made into film. It is used for printing paper film of ceramic (or enamel) products. The fired ceramic (or enamel) patterns have bright color and smooth texture. The flower paper is characterized by convenient use, low cost, smaller than the original glue, greatly reducing the decal process and high color burning rate. At present, most porcelain factories in China have formed relatively formal production lines for standardized production. Therefore, the demand for PVB in the ceramic (or enamel) flower paper industry is increasing.
Application field of polyvinyl butyral -- electronic adhesive
Polyvinyl butyral contains hydroxyl, vinyl acetate and butyraldehyde, which has high bonding properties. Phenolic Resin was added into PVB ethanol solution to make adhesive, which can be used for a long time at 120 ℃. The product has strong adhesion to metal, wood, leather, glass, fiber and ceramics; FRP can be manufactured to replace non-ferrous metals such as steel, aluminum and copper; The adhesive made by adding this product and curing agent into epoxy resin is often used for bonding and assembly of electronic instrument components, bonding between metal and porous materials, emergency repair, etc. it can also be used in the field of electronic ceramics. In the development of ceramic integrated electronic circuits, this product with medium viscosity and low hydroxyl is used as ceramic powder adhesive to increase the primary strength of ceramics.
Application field of polyvinyl butyral -- copper foil adhesive
Polyvinyl butyral (PVB) and phenolic resin cooperate to produce copper foil adhesive, which is used in the production of copper clad laminate. It has good peel strength and tin welding temperature resistance, and is widely used in various fields.
Application field of polyvinyl butyral - self adhesive enamelled wire paint
Polyvinyl butyral is the main raw material of self-adhesive enamelled wire paint. After the enameled wire is wound and formed in the electrodes of motors, electrical appliances and instruments, as long as it is heated for several minutes at a certain temperature or treated with appropriate solvent, the coils can be bonded together by themselves without impregnation and drying.
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