At present, the equipment and manufacturing process of domestic manufacturers of polyvinyl butyral are constantly getting closer to those abroad. For example, the wonderful use of polyvinyl butyral (PVB) has occurred in the printing industry and ceramic industry. Therefore, the domestic application of polyvinyl butyral (PVB) has an obvious upward trend in recent years.
For example, in the glass industry, it is because polyvinyl butyral (PVB) has good low-temperature impact strength, windability, light transmittance, light resistance, weather resistance, sound insulation, UV insulation and other properties, so that once the laminated glass is sealed together, the glass sandwich (i.e. laminated material) will appear as a whole and look like ordinary glass. For example, in the porcelain industry, polyvinyl butyral is made into a film and used for printing paper film of ceramic (or enamel) products. First, it reduces the original glue small paper Decal process, reduces the production cycle and production cost, and second, it makes its ceramic (or enamel) patterns bright in color and smooth in texture.
With the rapid development of science and technology in recent years, more and more industries have found the characteristics of polyvinyl butyral (PVB): high strength, high toughness, fatigue resistance, corrosion resistance and so on. Compared with traditional materials, polyvinyl butyral (PVB) is more and more widely used because of its larger development space and wider application fields!
Application field of polyvinyl butyral -- safety glass
The membrane made of polyvinyl butyral (PVB) is a special product used to manufacture safety glass and bulletproof glass. Safety glass is a special glass made of a layer of PVB diaphragm sandwiched between two layers of ordinary glass. It has good low-temperature impact strength, windability, light transmittance, light resistance, weather resistance, sound insulation, ultraviolet insulation and other properties. When subjected to strong external impact, PVB diaphragm can absorb impact energy, so that the glass will not break or prevent debris from hurting people. Moreover, the safety glass added with PVB diaphragm has the characteristics of high transparency, water resistance and aging resistance, and can be used in the environment of - 60 ℃. In addition, it can also be used as transparent material to replace plexiglass.
Application field of polyvinyl butyral -- ceramic film flower paper
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.