Greenflex HN 70 EVA resina de copolímero, adesivo de fusão quente composto grau

In corrugated case and carton closing, Greenflex HN 70 is compounded as the primary EVA backbone for hot-melt formulations in which sealing speed, low-temperature fibre tear on kraft liner, and clean machining at the compression section are the release criteria rather than adhesive hardness alone. The resin’s high vinyl acetate content suppresses polyethylene crystallinity and shifts the solidification profile toward a broad, low-energy recrystallisation window, which permits compression cycles between 0.3 s and 1.2 s on high-speed case erectors before the board springs back. In food-contact secondary packaging, adhesive materials must comply with FDA 21 CFR 175.105 for adhesives used in packaging with no functional barrier and with EU Regulation 10/2011 when the container falls under plastics food-contact legislation; migration testing is conducted under EN 1186-1 and overall migration must not exceed 10 mg/dm². A formulation that balances open time and set speed typically contains 30–40 wt% Greenflex HN 70, 35–45 wt% hydrogenated C5/C9 hydrocarbon tackifier, 20–30 wt% Fischer-Tropsch wax, 0.5–1.0 wt% hindered phenolic antioxidant, and 0.2–0.5 wt% acid scavenger or optical brightener when so specified.

Compounding is carried out in a jacketed sigma-blade mixer or a co-rotating twin-screw extruder having an L/D ratio of 40:1 to 48:1; barrel temperatures are staged from 120 °C to 155 °C, and the melt is filtered through a 200 μm screen pack to remove char particles and insufficiently dispersed tackifier domains. On the packaging line, the adhesive is melted at 150–170 °C and delivered through a slot nozzle or wheel applicator at viscosities commonly between 800 mPa·s and 2,000 mPa·s; coat weights range from 0.5 g/m to 2.5 g/m depending on flute type and board stiffness. Terminal finished types include regular slotted containers, die-cut mailers, wrap-around blanks, and corrugated trays. A processing conflict arises when wax content exceeds 30 wt% or when melt temperature drops below 150 °C: the high-VA phase can separate from the wax phase, yielding skip pattern application and inadequate compression set, whereas temperatures above 180 °C accelerate oxidative yellowing on bleached board.

What Limits Spine Flexibility and Cold Crack Resistance in Perfect Binding?

For perfect binding of softcover books, the hot melt is pumped from a premelter at 150–170 °C through a slot nozzle onto a milled spine; the dominant failure modes are spine cracking at temperatures below 5 °C and page pull after repeated flexing. The use of Greenflex HN 70 at 18–28 wt% in a bookbinding hot-melt formulation increases low-tack energy absorption without the excessive openness that prevents high-speed cover nipping. The remaining components are typically 40–50 wt% rosin ester tackifier, 15–25 wt% paraffin or Fischer-Tropsch wax, 10–15 wt% calcium carbonate filler, and 0.5–1.0 wt% stabilizer. Regulatory compliance for book adhesives sold in the European Union requires REACH registration under EC 1907/2006; children’s book adhesives may be screened according to EN 71-3 migration limits for heavy metals, while low-VOC declarations are often benchmarked against VDA 270 or client-specific odour limits. Production is usually continuous or semi-continuous: after mixing at 130–160 °C, the adhesive is cast through a 0.3–0.6 mm slot at 160–175 °C, the cover is nipped at 0.2–0.6 MPa, and the block is cooled to below 30 °C before three-knife trimming. Finished part types generated by this process are perfect-bound paperback books, high-page-count catalogues, layered repair manuals, and educational softcover directories.

Disposable hygiene elastic attachment imposes a narrow processing window in which pump-to-application viscosity, elastic creep resistance at body temperature, and thin PE film thermal damage define the acceptable additives and coat weight. Greenflex HN 70 serves as a high-polarity EVA modifier in formulations where 20–30 wt% resin is combined with 40–55 wt% hydrogenated hydrocarbon tackifier, 10–20 wt% naphthenic or paraffinic process oil, 0–5 wt% microcrystalline wax, and 0.5–1.0 wt% hindered phenolic antioxidant. Industry compliance for hygiene adhesives is not governed by a single food-contact standard; instead, skin-contact safety is commonly assessed using ISO 10993-5 for in vitro cytotoxicity and ISO 10993-10 for skin sensitisation and irritation when the converter requires medical-grade documentation, while REACH EC 1907/2006 Annex XVII entries 51 and 52 restrict phthalate plasticisers in childcare articles. On a production line, a slot die coater is fed from a continuous melt system at 140–160 °C; elastic strand bond coat weights range from 3 g/m² to 8 g/m², whereas backsheet lamination and waistband construction require 10–25 g/m². Nip pressure is maintained between 0.2 bar and 1.0 bar, and line speeds commonly reach 200–600 m/min. The principal process conflict is that application above 165 °C can burn through 12–20 μm polyethylene backsheet film, while temperatures below 135 °C produce melt fracture, adhesive throw-off, and inconsistent strand bonding. Terminal finished types include infant diaper leg cuffs, waistbands, adult incontinence pads, and ultrathin sanitary napkin cores.

Profile Wrapping and Edgebander Adhesive Rheology

The conversion of high-VA EVA into edgebanding and profile-wrapping hot melts requires a pot-stable viscosity at 190–210 °C, rapid crystallisation after the press roll, and enough open time to align PVC, ABS, veneer, or polyester edge material before contact. A furniture-grade formulation generally contains 30–45 wt% Greenflex HN 70, 25–40 wt% hydrogenated hydrocarbon tackifier, 10–25 wt% calcium carbonate filler, 5–15 wt% macrocrystalline wax, and 0.5–1.0 wt% antioxidant. The reference compliance framework is EN 204 classification D3 for interior non-structural thermoplastic wood adhesives, plus French NF EN 12765 for woodworking adhesives where load-bearing classification is not required; emission and odour limits are often established by VDA 270 or by furniture emission classes. During application, the adhesive is melted in a heated hopper and transferred by a gear pump to a roller or slot nozzle on an edgebander; line speeds of 10–25 m/min require open times between 2 s and 8 s and compression pressures of 0.3–0.8 MPa. Filler loading above 25 wt% reduces stringing and adhesive consumption but raises melt viscosity and can produce edge brittleness below −10 °C; Greenflex HN 70, with its high VA content, offsets some of that brittleness at the interface. Terminal products include PVC and ABS edge-banded furniture panels, veneered MDF doors, kitchen cabinet fronts, and profile-wrapped drawer fascias.

When Tackifier Loading Exceeds 45 wt% in High-Speed Label Adhesives

At high-speed label converting, the adhesive layer is expected to wet coated paper and clear polypropylene face stocks within milliseconds, release cleanly from the liner, and resist shear creep at warehouse temperatures above 40 °C. Greenflex HN 70 is used at 15–25 wt% as a polar compatibilizer and cohesive strength donor in hot-melt pressure-sensitive label formulations; the balance is 45–60 wt% rosin ester or hydrogenated hydrocarbon tackifier, 15–25 wt% naphthenic/paraffinic oil, 0–5 wt% wax, and 0.5–1.0 wt% stabilizer. Food-labeling compliance rests on FDA 21 CFR 175.125 for pressure-sensitive adhesives used in food contact, with FDA 21 CFR 175.105 applicable to dry food labels and EU Framework Regulation 1935/2004 governing overall suitability; migration testing is performed according to the EN 1186 series when the label is inside the package or in direct contact with food. Production is conducted on a hot-melt slot-die coater at 150–180 °C with coat weights from 15 g/m² to 30 g/m² onto glassine or polycoated release liner; transfer to face stock proceeds at 150–300 m/min through a cold laminating nip. Above 60 wt% tackifier, cohesive strength falls and bleed-through on uncoated paper increases; below 15 wt% EVA, mandrel peel and high-speed die-cutting generate adhesive stringing and matrix stripping failures. Terminal outputs are wrap-around bottle labels, pressure-sensitive primary labels for beverage pouches, clear-on-clear labels for personal care bottles, and adhesive-coated transfer webs for high-speed dispense.

Acoustical Insulation Bonding Requires a Low-Odor, Low-VOC EVA Matrix

For automotive interior lamination, the hot-melt system bonds nonwoven acoustic scrims to polyurethane foam cores, fibrous absorbers, and polyolefin backing layers where fogging, odour, and flame-spread performance are controlled by the OEM specification. Greenflex HN 70 is incorporated at 15–30 wt% with 30–50 wt% aliphatic hydrocarbon tackifier, 10–20 wt% low-volatility amorphous polyalphaolefin or polyisobutylene, 0–5 wt% wax, and 0.5–1.0 wt% stabilizer to minimize polar wax exudation. Interior materials are tested in accordance with VDA 278:2011 for VOC and fugitive emissions, VDA 270:2018 for odour, and ISO 3795 for horizontal burning rate; passenger-compartment applications generally require a burning rate no greater than 100 mm/min. Application is performed by heated spray, slot die, or roller coater at 150–180 °C; bond line compression is set at 0.1–0.5 MPa, and line speeds are 10–40 m/min depending on foam density and scrim grammage. The processing boundary is defined by the foam substrate: prolonged nozzle temperatures above 190 °C induce visible foam collapse and odour, while inadequate preheating of the nonwoven scrim below 30 °C causes adhesive skin-over and poor fibre penetration. Terminal interior parts include headliners, door panel inserts, trunk side trim, seat back panels, and under-carpet acoustic pads.