S-LEC K

Polyvinyl butyral resin S-LEC B and polyvinyl acetal resin S-LEC K are among the most widely used and reliable polymer materials in today's industrial fields. The success of these materials comes from their special chemical structure. It's a careful mix of hydroxyl groups, which help with adhesion and reactivity, and acetal units, which add flexibility and water resistance to the molecular chain. Because of this balance, they can be used as either thermoplastic or thermosetting resins. They are important in many industries, including electronics, cars, coatings, and printing. 1. Electronics and Energy Sector In precision manufacturing, many materials need temporary binders to hold their shape before the final molding process. After molding, these binders have to fully break down and evaporate when exposed to high heat. S-LEC B/K resins are a good option for this purpose because they mix well, stick properly, and their thermal decomposition can be controlled. ♣ Ceramic and Metal Powder Binders Applications: Molding of ceramic or metal powders in flat panel displays (FPDs), solar cells, and various electronic components. Value: As a powder binder, S-LEC B/K effectively disperses particles and provides good dimensional stability, ensuring the integrity of the green body structure before sintering. The resin decomposes cleanly during high-temperature sintering, according to thermogravimetric analysis. Decomposition mainly happens between 300°C and 500°C. This prevents leftover material from negatively impacting the final performance of the electronic parts. Specific Grades: Specific S-LEC B grades with high molecular weights are advised for this use because of their strong film durability and bond. ♣ Printed Circuit Board Adhesives S-LEC B/K resins are typically used in combination with thermosetting resins such as phenolic resins as adhesives between printed circuit board prepregs and copper foil. Their contributions include: Flexibility and Solderability: The flexibility provided by S-LEC B/K improves the stress absorption capacity of the cured resin system, helping to enhance the adhesive layer's resistance to thermal shock and ensuring excellent peel resistance. High Tg Advantage: In PWB applications with extremely high heat resistance requirements, the high glass transition temperature (Tg) grades of S-LEC K (e.g., S-LEC K KS-5 or S-LEC K KS-10) are even more important, providing the necessary thermal stability to withstand subsequent processing temperatures.   2. Coatings and Varnishes S-LEC B/K resin is also useful in coatings and varnishes because it sticks well to many surfaces like metals, plastics, and glass. Also, it works well with other resins for crosslinking, which is a key advantage. ♣ Wash Primer Main Function: This is one of the most classic applications of S-LEC B/K. It is a pretreatment primer for metals such as steel and aluminum, effectively improving the adhesion of subsequent topcoats to the metal surface and providing short-term rust protection. Applications: Widely used in structural components requiring underlying protection, such as ships, bridges, automotive refinish paints, and rail vehicles. Formulation Advantages: S-LEC B/K shows great compatibility by creating strong bonds with many topcoats, such as those made from PVC, melamine, or oil-based phenolic coatings. ♣ Metallic Varnishes and Baking Coatings S-LEC B/K, when mixed with phenolic resin pre-condensate, can be used to create high-quality baking coatings for food containers. Its addition significantly improves the toughness, adhesion, and service durability of the coating. In metal foil varnishes, this resin provides a transparent, flexible protective layer. ♣ Leather Coatings S-LEC B grades, due to their unique chemical structure, offer high flexibility and low-temperature impact resistance, making them particularly suitable for leather coatings. Leather surfaces coated with S-LEC B resin exhibit excellent elongation at room temperature, with no significant loss of performance even at low temperatures, forming a soft and resilient film on the leather.   3. Printing Inks In the printing ink field, S-LEC B/K resin acts as a pigment binder and dispersant, suitable for flexographic and gravure printing. Key Properties: Grades suitable for inks are typically low-viscosity S-LEC B/K, such as S-LEC B BL-10. Function: The resin ensures uniform dispersion of pigments in solvents and provides strong adhesion to substrates (such as plastic films) after ink curing. Its non-toxic and odorless properties make it advantageous in food packaging and applications where odor is critical.   4. Specialized Adhesive Applications Besides its application in PWB (Polarization and Welding), S-LEC B/K is also used as a key adhesive, either alone or in combination with other materials. ♣ Enamelled Coil Bonding Dipping or coating the enameled wire of a coil with an S-LEC B/K solution and then heating to melt or cure the resin achieves strong bonding and fixation between conductors. This is used in the manufacture of coils for motors and transformers, improving structural stability and insulation. ♣ Adhesive Formulation Substrates S-LEC B/K has hydroxyl groups in its structure, which allows it to cross-link with materials like isocyanates or epoxy resins. This process creates composite adhesives that have good heat resistance, toughness, and adhesive properties.   5. Other Miscellaneous Applications The versatility of S-LEC B/K resin also makes it play an important role in many niche professional fields. ♣ Reflective Film Adhesive In the manufacture of reflective films (such as road traffic signs), S-LEC B/K serves as an adhesive for the reflective layer of glass beads. Its advantages lie in its high film transparency, excellent dispersion of pigments (such as aluminum powder), and strong adhesion to plastic films such as PET. ♣ Magnetic Recording Tape Coating The resin exhibits excellent dispersibility and adhesion to magnetic powders, making it suitable for use as a magnetic powder coating adhesive in advanced magnetic recording tapes (such as audio and video tapes). ♣ Dye Transfer Ribbon Inks In sublimation transfer technology, S-LEC B/K resin is used to manufacture dye inks due to its excellent dispersibility for sublimated dyes.   The S-LEC B/K resin series has found widespread use in modern industry because its chemical structure can be modified to provide good adhesion, crosslinking, flexibility, and a wide glass transition temperature range. S-LEC B is used in both flexible and traditional coatings, while S-LEC K is used in high glass transition temperature electronic adhesives. These resins are important high-performance materials that help to advance industrial innovation and improve products.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

S-LEC B and S-LEC K are types of polymers that work well in coatings, adhesives, and electronics. They can handle many different and difficult jobs because of how their molecules are arranged. Specifically, their solubility and how they handle heat are carefully managed. 1. Solubility Characteristics: The Structural Basis for Solvent Selection S-LEC B/K resins are quite soluble, dissolving in alcohols, esters, ketones, and aromatics, especially well in alcohols. Solubility differences among grades show variations in their chemical makeup. 1.1 The Mechanism of Structure's Influence on Solubility Solubility is primarily constrained by the contradictory relationship between the hydroxyl content and acetal content on the resin molecular chain. Hydroxyl Content: Hydroxyl groups exhibit polarity; resins with a greater amount of hydroxyl content show increased hydrophilicity and polarity. Because of this, the resin will dissolve better in polar solvents like alcohols and become more reactive with thermosetting resins. Still, too much hydroxyl content can make the resin less flexible and more vulnerable to water damage. Acetal Content: Acetal units are nonpolar groups. The higher the acetal content, the more pronounced the nonpolar characteristics of the resin. This makes it more soluble in nonpolar solvents and improves its flexibility, water resistance, and compatibility with other nonpolar resins. 1.2 Solubility Differences Between Models Analysis of the solubility table reveals different solvent preferences for different models: S-LEC B low molecular weight, high hydroxyl grades (e.g., S-LEC B BL-1): These grades have a high hydroxyl content (e.g., BL-1H has a hydroxyl content of approximately 30 mol%), therefore exhibiting complete solubility in most alcohol solvents (e.g., methanol, ethanol, isopropanol) and strongly polar solvents (e.g., N,N-dimethylformamide). S-LEC K high Tg grades (e.g., S-LEC K KS-1): S-LEC K resins are designed to provide high thermal stability, and their molecular structure can be more tightly packed. Some KS grades, though still polar due to their hydroxyl content (around 25 mol%), either swell or partially dissolve in alcohols like methanol and ethanol. This suggests the acetal structure affects how well these polar solvents wet the molecules. This behavior shows the distinct properties of their chemical composition. 1.3 Advantages of Mixed Solvents One characteristic of S-LEC B/K is that it allows for a wider range of water tolerance in solvents. Furthermore, using mixed solvents generally produces better dissolution results because: Reduced viscosity: Mixed solvents help reduce the overall viscosity of the solution, facilitating application handling. Storage stability: Mixed solvents help maintain stable solution viscosity, which is beneficial for long-term storage. Optimized solubility: The polar/non-polar balance of the mixed solvents allows for more effective wetting of the three structural units of the resin.   2. Thermodynamic Properties: The Dominant Role of Tg and Softening Point The thermal properties, like the glass transition temperature (Tg) and softening point, are key to how well a resin holds up and can be molded at high temperatures. The S-LEC B/K series comes in a variety of Tg values, ranging from 59°C to 110°C. This allows them to be used in situations requiring flexibility at low temperatures or heat resistance when things get hot. 2.1 Structural Differences in Glass Transition Temperature (Tg) S-LEC K (High Tg Type): S-LEC K resin utilizes shorter acetaldehyde side chains (R:CH3), resulting in a denser molecular chain packing and achieving the highest Tg value in the series. For example, both KS-3 and KS-5 can reach a Tg of 110°C, making them ideal materials for applications requiring high thermal stability, such as bonding electronic components. S-LEC B (General Purpose and Flexible Type): S-LEC B employs longer butyraldehyde side chains (R: -CH2CH2CH3), increasing the spacing between molecular chains and free volume, resulting in a relatively low Tg. For example, BL-10 has a Tg of only 59℃. This lower Tg endows S-LEC B with excellent toughness and flexibility, exhibiting outstanding impact resistance at low temperatures. 2.2 Synergistic Effect of Tg and Molecular Weight On the Tg graph (Figure 9), the Tg of the same acetal type (e.g., S-LEC B) generally shows a slight increasing trend with increasing molecular weight. For example, the Tg range of medium molecular weight grades (e.g., BM-1) and high molecular weight grades (e.g., BH-3) is roughly between 60℃ and 70℃. Higher molecular weight contributes to improved thermodynamic stability of the polymer. 2.3 Softening Point The softening point is an important indicator for measuring the hot melting behavior of resins. The softening point diagram (Figure 10) shows that the S-LEC B/K grades have a wide softening point range, from approximately 100°C to over 200°C. Consistent with the Tg trend, high Tg grades of S-LEC K, such as KS-5, can achieve softening points above 200°C, giving this resin a significant advantage in hot-melt applications and high-temperature processing.   3. Thermal Decomposition Behavior: TG Analysis Insights Thermogravimetric analysis (TG) is used to study the mass loss of resins during heating, revealing their thermal decomposition characteristics. TG analysis of S-LEC B grades (e.g., BM-S and BM-2) shows differences under different atmospheres: Inert Atmosphere (N2): Under nitrogen, the resin exhibits a relatively simple and rapid mass loss process. Decomposition typically begins around 350°C and completes major decomposition around 450°C. Oxidizing Atmosphere (Air): Under air, the decomposition process typically presents a multi-stage mass loss curve. The first stage of decomposition occurs between 300°C and 400°C, followed by a second stage of oxidative decomposition at approximately 450°C to 550°C, ultimately potentially leading to complete combustion.   The solubility and thermodynamic properties of S-LEC B and S-LEC K resins form the basis for their versatile applications. By precisely controlling the side chains (butyraldehyde and acetaldehyde) of the acetal units, as well as the ratio of hydroxyl groups to molecular weight, this series of resins achieves the following objectives: Solubility: Solvent mixtures balance polar (hydroxyl) and non-polar (acetal) characteristics to suit different coating types. Mixing solvents helps reach the required application viscosity. Thermodynamic Properties: Flexible switching between the high Tg of S-LEC K (up to 110°C) and the low Tg of S-LEC B (down to 59°C) ensures a wide range of applications, from low-temperature flexibility to high-temperature heat resistance.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

High-performance resins hold a unique position in the landscape of modern industrial materials due to their superior comprehensive properties. Among many similar products, polyvinyl butyral resins S-LEC B and S-LEC K, with their unique and flexible chemical structures, have become key solutions in fields ranging from high-precision electronics manufacturing to specialty coatings. S-LEC B was first introduced in the 1930s, initially used in industry as an interlayer film for safety glass, establishing its position among high-performance polymers. S-LEC K, as a functional extension of this series, focuses on applications with stringent requirements for heat resistance due to its high glass transition temperature (Tg). Although both are collectively referred to as the S-LEC B/K series, their performance differences are rooted in their sophisticated chemical structure design.   1. Core Chemical Structure: The Source of Performance Both S-LEC B and S-LEC K are derived from polyvinyl alcohol (PVA). These are prepared by reacting PVA with specific aldehydes in a reaction called acetalization. Due to limitations in the manufacturing process, the acetalization reaction cannot be completed completely, resulting in the final resin molecular chain retaining three crucial structural units that collectively determine the final product's properties:     ♠Acetal Unit: This is the core functional unit of the resin, imparting hydrophobicity and flexibility to the material. The fundamental difference between S-LEC B and S-LEC K lies in the side chain (R group) of this unit: S-LEC B: The aldehyde group R used in acetalization is -CH2CH2CH3. The longer side chain gives S-LEC B superior flexibility and solubility in nonpolar solvents. S-LEC K: The aldehyde group R used in acetalization is -CH3. The shorter side chain results in a more compact packing of molecular chains, giving S-LEC K a higher glass transition temperature (Tg) and better thermal stability. ♣Hydroxyl Unit (OH):The unit refers to the part of PVA that hasn't reacted and remains within the resin molecule in a specific ratio. The hydroxyl group gives the resin good adhesion—particularly to polar surfaces like metals and glass—and makes it attract water. More crucially, this hydroxyl group lets the resin form cross-links with resins that harden when heated, like epoxy resins and isocyanates. This hardening broadens the resin's use. ♣Acetyl Unit: These trace units remain because of incomplete breakdown during PVA production. The proportions of these three units in the molecular chain, precisely controlled through the manufacturing process, constitute the vast spectrum of the S-LEC B/K series resin grades.   2. Performance Regulation: A Precise Balance of Influencing Factors The physical and chemical properties of this series of resins are not fixed but are precisely regulated by the following three core factors: 2.1 The Unity of Opposites and Hydroxyl Content The acetal and hydroxyl content in the molecular structure usually exhibit an inverse relationship, and their balance directly determines the key properties of the resin: Flexibility and Water Resistance: The higher the acetal content, the more pronounced the non-polar characteristics of the resin, the better the flexibility, water resistance, and compatibility with non-polar resins. Adhesion and Reactivity: The amount of hydroxyl groups present strongly affects how well a resin sticks, particularly when polar adsorption is needed. At the same time, the hydroxyl content also influences how the resin reacts with thermosetting resins and how easily it dissolves in polar solvents. 2.2 The Decisive Role of Molecular Weight in Application Performance The molecular weight (degree of polymerization) of the resin directly affects the following crucial application characteristics: Film Toughness: The higher the molecular weight, the stronger the toughness of the film or coating made from the resin. Solution Viscosity: Molecular weight is the main factor affecting solution viscosity. At a given solids content, higher molecular weight grades offer higher solution viscosity, making them suitable for certain thickening or high-viscosity applications. Adhesion: Molecular weight also significantly impacts final adhesive strength. The S-LEC B/K series offers a wide molecular weight range, from approximately 14,000 to 130,000. Engineers can choose materials based on the needed viscosity, strength, and flexibility by picking different acetal contents. 2.3 Thermodynamic Properties: Tg and Heat Resistance Stability The glass transition temperature (Tg) is a core indicator of a material's heat resistance. This series of resins covers a Tg range from 59°C to 110°C, enabling them to meet the needs of applications ranging from low-temperature applications requiring high flexibility to high-temperature applications requiring high stability: Advantages of S-LEC K: S-LEC K acetal resins, such as S-LEC K KS-1, S-LEC K KS-5, and S-LEC K KS-10, usually show the highest glass transition temperature (Tg), reaching up to 110°C. This makes them good for uses needing high heat resistance and a high softening point—some types can reach 200°C. Examples include bonding printed circuit boards and in difficult electronic parts. Advantages of S-LEC B: S-LEC B acetal resins, which have lower glass transition temperatures, provide good impact resistance at low temperatures and increased flexibility.   3. Functional Expansion: Crosslinking Reaction and Thermosetting Potential     The S-LEC B/K series is not limited to use as a thermoplastic material. Because it has many hydroxyl groups, this substance can crosslink and cure when mixed with different thermosetting resins like phenolic resins, epoxy resins, or isocyanates. This crosslinking capability is a significant advantage in industrial applications, allowing engineers to combine the superior toughness, adhesion, and flexibility of thermoplastic resins with the high heat resistance, chemical resistance, and mechanical strength of thermosetting resins through formulation design. The result is composite materials that perform well, overcoming the limits of single resins. For instance, this crosslinking and curing process is key to achieving the needed performance in high-end coatings and adhesives.   S-LEC B and S-LEC K resins are important types of high-performance polymers. These resins are valued because their properties, like flexibility and adhesion, can be adjusted. This is achieved by carefully managing the acetal side chains (using butyraldehyde or acetaldehyde) and the amount of hydroxyl content in the resin. This meticulous control over molecular structure ensures that S-LEC B/K can continuously provide high-performance material solutions for multiple key industrial sectors, including electronics, automotive, coatings, and adhesives.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com