Changchun PVB B-08HX

Polyvinyl butyral (PVB), due to its excellent transparency, toughness, superior metal adhesion, and good film-forming properties, occupies an important position in coatings, adhesives, printing inks, and safety glass interlayers. By adjusting the degree of polymerization (molecular weight), degree of acetalization, and residual hydroxyl content, PVB is endowed with diverse physicochemical properties, forming a matrix of specifications to meet different industrial needs.     1. Core Specification System: Performance Comparison of HX, SY, and TX Series The differences in PVB specifications are mainly reflected in two dimensions: viscosity (molecular weight) and degree of acetalization. 1.1 Differences in Viscosity (Molecular Weight) Grades Viscosity is a core indicator determining the processing fluidity and film strength of PVB. ♠ Low-viscosity grades (PVB Resin B-02HX, CCP B-03HX): Performance characteristics: Excellent dissolution speed and low viscosity at high solid content, with strong permeability. Key applications: Mainly used in printing inks, metal foil coatings, and penetrating primers. Due to its shorter molecular chains, it provides a smooth film surface and good wettability. ♠ Medium-viscosity grades (CCP B-06HX, Changchun PVB B-08HX): Performance characteristics: Balances processability and toughness, making it the most widely used "all-rounder" grade. Key applications: Widely used in wood coatings (sealers) and ceramic adhesives. Its viscosity is sufficient to maintain pigment suspension while ensuring the strength of the green body after sintering. ♠ High-viscosity grades (Changchun PVB B-17HX, PVB B-20HXB): Performance characteristics: High molecular weight, resulting in extremely high impact strength and tensile strength after film formation. Key applications: Primarily used in safety helmets/composite materials and peelable protective films. In these areas, PVB provides strong structural support, preventing materials from shattering under stress. 1.2 Trade-off between Degree of Acetalization and Polarity ♣ HX series (standard type): The degree of acetalization ranges from 72-88wt%, providing good general solubility (e.g., in alcohol solvents). ♣SY series (high degree of acetalization): This series has a higher butyral group content. Comparative Advantages: Increased acetal content means enhanced hydrophobicity. Compared to the HX series, the SY series exhibits superior solubility in non-polar solvents (such as methyl ethyl ketone and toluene mixtures), lower water absorption, and better dimensional stability. It is commonly used in special paints or precision electronic adhesives requiring excellent water resistance. ♣ TX Series (Special Modification): Comparative Advantages: Designed for high-temperature processing environments. Its optimized residual hydroxyl group distribution significantly improves heat resistance after crosslinking with resins. Key Applications: Specifically used in printed circuit boards (PCB) and copper foil adhesives, capable of withstanding the high temperatures during the soldering process.   2. Comparison of Solubility Behavior in Different Solvent Systems The performance of PVB is highly dependent on the choice of solvent. The manual indicates that PVB is readily soluble in alcohols, ketones, and esters, but insoluble in pure hydrocarbons. Solvent Strength Comparison: Alcohols (such as ethanol and isopropanol) are the most commonly used solvents, providing stable viscosity; while adding a small amount of aromatic solvents (such as toluene and xylene) not only reduces costs but also effectively lowers system viscosity and improves coating efficiency. Effect of Water Content: PVB is extremely sensitive to water. The manual emphasizes that even a very small amount of water in the solvent can lead to a sharp increase in solution viscosity, or even gelation. Therefore, in safety glass or optical films requiring high transparency, the solvent specifications must be strictly controlled.   3. Comparison of PVB's Functional Roles in Multiple Fields Adhesion vs. Sintering Residue (Ceramic Industry) In ceramic adhesives, compared to other organic resins, PVB's advantage lies in its extremely high green strength. It allows the powder to be tightly packed in the mold and has a "residue-free" characteristic during the sintering process, ensuring the electrical performance and mechanical structure of the ceramic product. Anti-corrosion Function vs. Decorative Function (Metal Coating) In wash primers, PVB reacts with chromates and phosphates to form a chemically bonded layer on the metal surface, providing excellent anti-corrosion performance. This contrasts sharply with its role as purely a leveling agent and film-forming agent in baked enamel coatings for metal cans. Enhanced Toughness (Resin Modification) When PVB is used in combination with epoxy resin or phenolic resin, its function shifts from being the "main film-forming component" to a "modifier." Compared to the brittleness of pure epoxy resin, the addition of PVB significantly improves impact toughness and adhesion to metals due to the incorporation of long-chain PVB into the cross-linked network formed during the resin curing process.   Low-viscosity grades prioritize flow and penetration, making them ideal for inks and primers; High-viscosity grades prioritize strength and toughness, making them core components for structural materials and protective films; High acetal content and modified grades (SY/TX) provide specialized solutions for extreme environments requiring water and heat resistance.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

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