Changchun PVB B-08HX

General Properties Polyvinyl butyral (PVB) resin appears as white, spherical, porous granules or powder, with a specific gravity of 1.1; however, its bulk density is only 0.20~0.35 g/ml.   Thermal Properties The glass transition temperature (Tg) of polyvinyl butyral (PVB) resin ranges from 50°C for low degrees of polymerization to 90°C for high degrees of polymerization; the glass transition temperature (Tg) of polyvinyl acetal resin is between 90°C and 110°C; this glass transition temperature can also be adjusted by adding an appropriate amount of plasticizer to lower it to a suitable operating temperature.   Mechanical Properties Polyvinyl butyral (PVB) resin has excellent film-forming properties and imparts excellent tensile strength, tear strength, abrasion resistance, elasticity, flexibility, and gloss to coatings; it is especially used as an interlayer in laminated safety glass, giving the glass strong impact and penetration resistance, and remains irreplaceable by other materials to this day.   Chemical Properties Polyvinyl butyral (PVB) resin coatings have good water resistance, alkali resistance, and oil resistance (resistant to aliphatic, mineral, animal, and vegetable oils, but not castor oil). Because PVB contains a high hydroxyl content, it has good dispersibility for pigments, and is therefore 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 has good adhesion to glass, metals, plastics, leather, and wood.   Chemical Reaction Any chemical that reacts with secondary alcohols will also react with PVB. Therefore, in many PVB applications, it is often used in combination with thermosetting resins, allowing it to undergo cross-linking and hardening with the hydroxyl groups 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, coatings with different properties (such as hardness, toughness, impact resistance, etc.) can be formulated.   Safety Properties Pure PVB is non-toxic and harmless to the human body.  Because it can be used with ethyl acetate or alcohols as solvents, PVB is widely used in printing inks for food containers and plastic packaging. As long as PVB does not come into direct contact with water, it can be stored for two years without significantly affecting its quality; PVB should be stored in a dry and cool place, avoiding direct sunlight, and heavy pressure should be avoided during storage.   Solubility PVB is soluble in alcohols, ketones, and esters. The solubility in various solvents varies depending on the functional group composition of the PVB itself. Generally, it is easily soluble in alcohol solvents, but methanol is less soluble for those with high acetal groups; the higher the acetal group content, the more easily it dissolves in ketone and ester solvents; PVB is easily soluble in alcohol ether solvents; PVB is only partially soluble in aromatic solvents such as xylene and toluene; PVB is insoluble in hydrocarbon solvents.   Viscosity Characteristics of PVB Solutions The viscosity of PVB solutions is greatly affected by the solvent formulation and the type of solvent. Generally, when using alcohols as solvents, the higher the molecular weight of the alcohol, the higher the viscosity of the PVB solution; aromatic solvents such as xylene and toluene, and hydrocarbon solvents can be used as diluents to reduce the viscosity of the PVB solution; the effect of PVB chemical composition on viscosity is summarized as follows: under the same solvent and the same content of each group, 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 or acetate group content, the lower the solution viscosity.   PVB Dissolution Method When using a single solvent or a mixed solvent, the dissolution process involves first adding the solvent, then adding the PVB at an appropriate speed while stirring.  During the addition, avoid the formation of clumps of PVB (as this will increase the dissolution time several times), thus speeding up the dissolution process. Maintain appropriate stirring intensity to disperse and swell the PVB until it is completely dissolved, forming a completely transparent solution.  Heating can also be used to shorten the dissolution time.  Generally, a ratio of aromatic to alcoholic solvents of 60/40 to 40/60 (by weight) can produce a PVB solution with lower viscosity.   Processing Properties Although PVB resin is a thermoplastic plastic, it has almost no processability before the addition of plasticizers. Once plasticizers are added, its processability becomes very easy. PVB is compatible with plasticizers such as phosphate esters like TBP and TCP; phthalate esters such as DOP, DBP, and BBP; and castor oil, polyethylene glycol, and triethylene glycol di-butyrate. For general coatings and adhesives, plasticizers are added to modify the resin characteristics to meet application requirements, such as film flexibility, lowering the resin's Tg point, lowering the heat sealing temperature, and maintaining low-temperature flexibility.   Compatibility PVB is compatible with a variety of resins, such as phenolic resins, epoxy resins, alkyd resins, and melamine resins. CCP PVB B-08SY, CCP PVB B-06SY, and CCP PVB B-05SY, which have higher acetal content, can be mixed with nitrocellulose in any proportion. PVB and alkyd resins are partially compatible. General-purpose PVB is compatible with low-molecular-weight epoxy resins, while high-molecular-weight epoxy resins require the selection of PVB with high acetal content for compatibility.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com