Our block hot melt adhesive (HMA) production utilizes a meticulously controlled, continuous process ensuring consistent quality, purity, and performance. Here’s a streamlined overview:
- Raw Material Selection & Handling:
- We source high-purity base polymers (EVA, APAO, Polyolefins, SBCs), tackifying resins (hydrocarbon, rosin esters), plasticizers (oils, waxes), stabilizers (antioxidants), and specialty additives.
- Materials undergo rigorous quality checks (QC) upon receipt. They are stored under controlled conditions (temperature, humidity) to preserve integrity.
- Precision Weighing & Pre-Mixing:
- Ingredients are precisely weighed according to the specific formulation using automated systems for accuracy.
- Solid components may undergo coarse pre-blending to facilitate a more uniform feed into the melt system.
- Controlled Melting & Homogenization:
- The pre-weighed/pre-mixed materials are fed continuously into a primary heated melt vessel or extruder.
- Intense heat (typically 150°C – 200°C) is applied under controlled atmospheric conditions (often inert gas like Nitrogen) to melt the components and prevent oxidation/degradation.
- High-shear mixing occurs within the melt unit. Powerful agitators or screw elements ensure thorough dispersion and molecular-level homogenization of all components (polymers, resins, waxes, additives). This is critical for achieving the target adhesive properties (viscosity, tack, bond strength).
- Filtration & Degassing:
- The molten adhesive passes through fine filtration systems (e.g., screen changers) to remove any potential impurities or unmelted particles, guaranteeing product purity.
- Optionally, the melt may pass through a degassing chamber under vacuum to remove any entrapped air bubbles or volatile components, ensuring a dense, defect-free final block.
- Continuous Casting (Key Stage):
- The purified, homogeneous melt is pumped under precise pressure control to the casting unit.
- It flows continuously onto a temperature-controlled, moving stainless steel belt or through a shaped die.
- The belt/die configuration determines the block’s final dimensions (e.g., standard blocks, slabs, specific profiles). This continuous casting method is central to our consistency.
- Controlled Cooling & Solidification:
- The molten layer traverses a precisely calibrated cooling tunnel beneath the casting belt or through cooled sizing units after the die.
- Chilled water or air circulates around/under the belt or over the extrudate, rapidly and uniformly solidifying the melt into a solid block without inducing internal stresses or crystallization issues. Cooling rate is critical for block structure and performance.
- Precision Cutting:
- The solidified, continuous ribbon of adhesive exits the cooling section.
- Automated cutting equipment (saws, guillotines, or flying knives) precisely cuts the ribbon into individual blocks of predetermined weight and dimensions (e.g., common sizes like 500g, 1kg, 5kg, 10kg blocks).
- Rigorous Quality Control (QC):
- Samples from each production batch undergo stringent laboratory testing against specifications:
- Physical Properties: Softening Point (Ring & Ball), Melt Viscosity (Brookfield), Density.
- Performance Properties: Peel Strength, Shear Strength (ASTM D4498), Tack (Quick Stick, Rolling Ball), Open Time.
- Appearance & Consistency: Color, clarity, homogeneity, absence of bubbles/contaminants.
- Only batches passing all QC checks proceed to packaging.
- Samples from each production batch undergo stringent laboratory testing against specifications:
- Automated Packaging & Labeling:
- Approved blocks are automatically or semi-automatically packed. Common methods include:
- Individually: Wrapped in release paper or coated parchment paper.
- Bulk: Placed in cardboard cartons, lined polybags, or shrink-wrapped on pallets.
- Each package is clearly labeled with product code, batch number, manufacturing date, safety information (SDS reference), and net weight.
- Approved blocks are automatically or semi-automatically packed. Common methods include:
- Storage & Distribution:
- Finished blocks are stored in a cool, dry warehouse away from direct heat sources and moisture.
- Products are shipped globally using appropriate logistics to maintain quality during transit.