RECICLEX CBIOP28025 EVA Copolymer Resin,Bio-Circular Attributed,Hot Melt Adhesive Grade

RECICLEX CBIOP28025 EVA Copolymer Resin, Bio-Circular Attributed, Hot Melt Adhesive Grade is an ethylene-vinyl acetate copolymer designed for thermoplastic hot-melt adhesive formulation. The grade designation CBIOP28025 encodes a nominal vinyl acetate comonomer content of 28% by mass and a nominal melt flow index of 25 g/10 min at 190 °C under a 2.16 kg load, as determined by ISO 1133-1:2022. The resin is supplied in pellet form for bulk handling in hot-melt compounding, case and carton sealing, bookbinding, profile wrapping, and product assembly operations where controlled open time, rapid set, and adhesion to fibre-based substrates are required.

The circular attribution is managed through mass-balance allocation of bio-circular feedstocks rather than through a change in the copolymer backbone. The statistical ethylene-vinyl acetate sequence, molar mass distribution, melt rheology, and thermal profile therefore remain within the same control limits as a fossil-derived EVA of equivalent VA content and melt flow index. Because the final polymer is chemically indistinguishable from conventional EVA in routine FTIR or DSC screening, the product can be introduced into existing hot-melt adhesive formulations with qualification focused on lot-to-lot melt index, VA content, moisture, and chain-of-custody documentation rather than reformulation of tackifier, wax, or stabiliser packages.

In high-pressure free-radical copolymerisation of ethylene and vinyl acetate, comonomer content controls polarity, crystallinity, glass transition temperature, and adhesive wetting. At 28% VA, residual crystalline ethylene segments provide cohesive strength after cooling, while the vinyl acetate sequences disrupt crystallinity and increase adhesion to polar surfaces. The nominal melt flow index of 25 g/10 min is selected for low application viscosity in nozzle and slot-die operations without excessive cold flow at room temperature. These two parameters are the primary specification anchors; density and melting endotherm are used as secondary identity checks.

What distinguishes CBIOP28025 from conventional EVA hot-melt grades?

Compared with a conventional fully fossil-based 28% VA EVA of the same melt flow index, the differentiation is the bio-circular mass-balance certification under ISCC PLUS, not a change in adhesive physics. The chain-of-custody documentation allocates a defined mass of renewable or bio-circular feedstock to the product; the final polymer cannot be distinguished from fossil-derived EVA by FTIR, DSC, or melt rheology alone. The operational benefit is therefore limited to downstream scope 3 carbon accounting and product declarations in packaging and adhesive converting. Life-cycle comparisons should follow ISO 14040:2006 and ISO 14044:2006, with system boundary, allocation method, and mass-balance period clearly stated. Published data for this specific bio-circular configuration is limited; the ISCC PLUS certificate and associated life-cycle inventory remain the authoritative documents.

Relative to lower VA hot-melt grades such as 18–19% EVA, the 28% VA content of CBIOP28025 increases polar surface attraction and reduces crystallinity. This shifts adhesion toward more polar paper, board, coated stock, and aluminium foil, and lowers the temperature required to form a melt. Relative to higher VA grades such as 33% EVA, the product retains a higher crystallite fraction after cooling, providing faster set and lower residual tack. Compared with metallocene polyolefin plastomers used in similar hot-melt applications, EVA typically exhibits broader compatibility with rosin ester and C5/C9 tackifier systems, higher stiffness after set, and faster viscosity reduction with temperature above the melting point. In contrast to polyamide or reactive polyurethane hot melts, this EVA grade is a non-reactive thermoplastic system; bonds are thermally reversible and do not develop crosslinked solvent resistance.

When comparative evaluations against conventional EVA are performed, the adhesive performance is commonly screened by ring-and-ball softening point per ASTM E28-18, Brookfield viscosity per ASTM D3236-15, 180° peel adhesion per ASTM D6862-11, and shear adhesion failure temperature per ASTM D4498-07. Specimen preparation and cooling rate must remain identical because the degree of crystallinity and peel values are strongly cooling-rate dependent. Users making bio-content or recycled-content claims must follow jurisdiction-specific accounting rules and the ISCC PLUS mass-balance guidance; the bio-circular grade is not designed to be biodegradable or compostable.

Before lot release for compounding, incoming quality control of CBIOP28025 generally covers the parameters listed in Table 1. The certificate of analysis should be read alongside the ISCC PLUS mass-balance statement because the bio-circular allocation does not alter the physical test values but does affect feedstock origin claims and traceability obligations.

These are nominal control targets for the grade class and do not replace the manufacturer’s batch certificate. When lot-to-lot variability outside the control limits is observed, the typical failure modes are viscosity drift in the adhesive mixer, change in open time, or inconsistent bead width on high-speed packaging lines. Such effects are best diagnosed with a rotational viscometer according to ASTM D3236-15 and ring-and-ball softening point according to ASTM E28-18 before changing formulation ratios.

Processing conditions on continuous hot-melt application lines

On a 200 L drum unloader with heated platen, a platen temperature of 120–140 °C, a transfer hose temperature of 140–160 °C, and a slot-die or bead nozzle temperature of 150–170 °C are representative starting conditions for EVA hot-melt grades with 28% VA and 25 g/10 min melt flow index. For gear-pump applicators with nozzle diameters of 0.3–0.5 mm, the melt viscosity is low enough to permit continuous bead deposition at line speeds above 50 m/min without excessive back pressure. Pump speed and hose length must nevertheless be limited because shear heating in gear pumps and narrow hoses can reduce the thermal history margin. On a 36:1 L/D twin-screw compounding extruder, the resin enters the feed throat at 110 °C and is discharged at 160 °C; screw elements producing high shear should be avoided because excessive shear heating above 190 °C accelerates deacetylation.

Thermal degradation of EVA in hot-melt equipment follows deacetylation and subsequent oxidation. The reaction liberates acetic acid, which can corrode brass nozzles and aluminium manifolds. The rate becomes significant above 190 °C when hold time exceeds 2 h. Heated reservoirs should therefore be nitrogen-blanketed and return lines should be short to reduce residence time. If the molten adhesive is held above 180 °C for more than 4 h, the system should be flushed to reduce char and gel accumulation. For resins stored in unsealed bags at relative humidity above 60%, pre-drying at 60–70 °C for 2–4 h in a desiccant dryer is recommended to reduce moisture to <0.1% before melt processing. Undried pellets can produce bubble defects in the applied adhesive film and intermittent pump surging due to steam generation.

Formulation compatibility is influenced by VA content and melt flow index. The resin is compatible with rosin ester tackifiers, hydrogenated hydrocarbon resins, paraffin and microcrystalline waxes, and Fischer-Tropsch waxes. Amine-functional silane coupling agents and strongly basic additives are not recommended because they promote deacetylation and can produce phase separation. The final formulation ratio is typically 25–35 wt% resin, 30–45 wt% tackifier, and 20–35 wt% wax and plasticizer, but the exact ratio must be adjusted to open time, set speed, viscosity at the application temperature, and adhesion to the target substrate.

On high-speed roll coaters, prolonged exposure of molten adhesive to air can produce a skin layer at the tank surface. The build-up of char and gel bodies in the application die is one of the primary production bottlenecks reported for EVA hot-melt systems. A nitrogen blanket on the adhesive reservoir at 0.5–1.0 bar positive pressure and filtration through 100–150 µm screens upstream of the die reduce nozzle blockage. When die-lip buildup is observed, the first corrective action should be lowering the adhesive temperature or reducing hold time rather than increasing pump speed, because the viscosity gain from degradation is the source of the defect.

Rheological characterisation under oscillatory shear at 160 °C can be performed with a parallel-plate rheometer using ISO 6721-10 or equivalent. Above the melting point, the material behaves as a shear-thinning viscoelastic liquid; the zero-shear viscosity decreases with increasing VA content and increasing melt flow index. The 25 g/10 min grade is selected to balance low application viscosity against sag resistance. In continuous application equipment, the viscosity at 150–170 °C is low enough for nozzle application but high enough to prevent excessive penetration into paperboard. Because this grade is a thermoplastic, the adhesive bond softens when exposed to temperatures approaching the softening point of the formulated product. It is not suitable for high-temperature structural service above approximately 80–90 °C unless the specific formulated adhesive has been validated by shear adhesion failure temperature testing. This operational boundary differentiates it from reactive polyurethane or polyamide hot melts. Low-temperature flexibility should be confirmed on the final formulation, because cold-flex data are formulation-dependent.

Regulatory status is a function of the formulated adhesive rather than the base resin alone. The base EVA is designed to conform to 21 CFR 177.1350 for ethylene-vinyl acetate copolymers; the completed adhesive may be covered under 21 CFR 175.105 if the converter demonstrates that the finished adhesive complies with the extraction and end-use limitations for food-contact adhesives. The resin should also be evaluated under EU 10/2011 when used in food-contact materials in the European Union. The supplier’s REACH registration and RoHS Directive 2011/65/EU Annex II declarations should be requested for the specific production site, because bio-circular feedstock allocation does not alter the regulatory chemistry of ethylene-vinyl acetate.

Storage in sealed bags at temperatures below 30 °C and relative humidity below 60% is recommended. Under these conditions, the resin retains specification properties for at least 12 months from the date of manufacture, although the manufacturer’s shelf-life statement should be confirmed per production site. Prolonged exposure to ultraviolet radiation or heat can cause oxidation and yellowing, particularly in the presence of transition-metal residues; an antioxidant package is typically added to the formulated adhesive rather than to the base resin.

For high-speed packaging closure, the adhesive formulated with CBIOP28025 is applied at melt temperatures of 150–170 °C onto corrugated and coated carton stock. Bond formation is governed by substrate wetting and subsequent crystallisation; open time is adjusted by wax content and application temperature, while set speed is measured on the packaging line by compression strength after 0.5–1.0 s cooling. For bookbinding, a formulation based on this grade is applied to the spine at 150–160 °C and then nipped immediately; adhesion to coated paper and joint strength are evaluated according to ASTM F88/F88M or equivalent sealing strength methods, though published data for this specific bio-circular grade is limited. In profile wrapping and product assembly, the adhesive is used in roll-coat and slot-die operations where the 25 g/10 min melt flow index permits thin film deposition of 50–100 µm thickness without excessive penetration into porous substrates.