ELVAX 3170SHB Copolímero de acetato de etileno e vinil

Hot-Melt Packaging Adhesives Require 2.5 g/10 min Melt Flow Control

For hot-melt packaging adhesives, ELVAX 3170SHB is specified with 18 wt% vinyl acetate comonomer and a melt flow rate of 2.5 g/10 min determined under ISO 1133-1:2022 at 190 °C/2.16 kg. In case and carton closing formulations, the copolymer is compounded at 25–35 wt% with hydrogenated rosin ester tackifier at 35–45 wt%, Fischer-Tropsch wax at 10–20 wt%, and hindered phenolic antioxidant at 0.3–0.8 wt%; polymer loadings below 20 wt% reduce fibre-tear cohesion, while loadings above 40 wt% generate slot-die head pressures above 4.5 MPa on conventional coating equipment. Compounding is run on a co-rotating twin-screw extruder with L/D 42:1, barrel zones 130–170 °C, die temperature 180 °C, melt filtration through 120-mesh breaker plates, and underwater pelletizing; wetted surfaces in melt contact are specified as 316L stainless steel because thermal excursions above 200 °C release acetic acid that corrodes carbon steel. The finished adhesive is applied through slot-die coaters at 165–175 °C with nip pressure 0.3–0.6 MPa; apparent viscosity measured by ASTM D3236 typically sits between 500 mPa·s and 5,000 mPa·s depending on wax dilution. Food-contact packaging adhesives are assessed under FDA 21 CFR 175.105 and FDA 21 CFR 177.1350, with migration verification under EU Regulation No 10/2011 for EU-market articles. Terminal products include corrugated case and carton closure, perfect-bound book spines, graphic arts layflat adhesives, and multi-wall bag seaming where open time is controlled between 2 s and 10 s before fibre tear. Pellets are pre-dried at 60 °C for 4 h when storage relative humidity exceeds 60%; surface moisture otherwise causes bubble formation in the slot-die application gap. The dominant production failure mode is batch-to-batch viscosity drift caused by incomplete pellet drying or by holding the adhesive tank above 190 °C over an entire shift.

What Occurs in a Stirred Paraffin Wax Kettle When 18 wt% High-Molecular-Weight EVA Is Added?

The addition of ELVAX 3170SHB to fully refined paraffin wax alters crystal nucleation and flexural resistance because the 18 wt% vinyl acetate comonomer disrupts wax crystal order and increases low-temperature ductility. In candle and corrugated board wax coating operations, the polymer is dosed at 2–8 wt% of total wax solids; pillar and container candle blends commonly use 3–6 wt%, while curtain-coating of corrugated board uses 1–3 wt% to avoid excessive melt viscosity at the coating head. Addition above 12 wt% causes cloud point elevation above 85 °C and may interfere with gloss retention, while below 1 wt% the effect on slumping resistance becomes statistically indistinguishable from unfilled paraffin. Processing is conducted in a steam-jacketed stainless steel kettle equipped with an anchor impeller running at 50–80 rpm at 110–130 °C; the polymer pellets are introduced slowly through the vortex after the wax has reached 110 °C, followed by high-shear rotor-stator dispersion at 2,500–3,500 rpm for 20–30 min to eliminate gel particles and optical streaks. The melt is then filtered through 80-mesh screen changers and deposited onto a pastillation belt or prilling tower. Compliance for candle applications falls under REACH Annex XVII restrictions on PAHs and general product safety; wax-coated paper used for dry food contact is assessed under FDA 21 CFR 176.170 for components of paper and paperboard in contact with aqueous and fatty foods. Relevant test methods include ASTM D87 for drop melting point, ASTM D938 for congealing point, and ASTM D1321 for needle penetration. Terminal finished products include pillar candles, container wax fill, wax-impregnated corrugated board for high-humidity environments, and thin wax paper laminations for confectionery interleaving. A production-scale failure observed in candle compounding is the formation of macroscopic gel specks when pellets are dumped into wax below 105 °C; these specks require rework and increase filtration pressure from 0.8 MPa to 2.0 MPa across the screen changer.

In solvent-borne lamination of aluminum foil to coated paperboard, ELVAX 3170SHB is dissolved at 35–40 wt% solids in a toluene/methyl ethyl ketone/ethyl acetate blend using a high-viscosity dissolver fitted with a 45° pitched-blade turbine at 180–220 rpm and jacket temperature 55–65 °C. The resin component of the dry adhesive film is maintained at 15–25 wt% of total solids, with the balance comprising rosin ester tackifier, microcrystalline wax, and 0.3–0.5 wt% hindered phenolic antioxidant. Reverse-roll or gravure coating deposits 3–5 g/m² dry coat weight onto the foil or paper web, followed by a three-zone drying tunnel at 60 °C, 75 °C, and 90 °C and lamination nip pressure of 0.4–0.7 MPa at 70–85 °C. Viscosity drift is controlled by continuously measuring solids content and holding the solvent ratio within ±1%; published data for the exact evaporation-rate profile of this formulation is limited, so production lines rely on near-infrared solvent monitoring at the gravure bath rather than theoretical drying models. Compliance for flexible food packaging is assessed under FDA 21 CFR 175.105 and FDA 21 CFR 177.1350, with overall migration testing under EU Regulation No 10/2011 and residual solvent limits agreed in the supply-chain food-contact risk assessment. Bond strength is verified by ASTM D1876 T-peel and direct fibre-tear evaluation. Terminal finished goods include aluminum foil/paper lidding for dry food sachets, paper/polyethylene laminations for multi-pack overwrap, and metallized paper soap wraps that must withstand foil-curl stress at −20 °C without tunnelling. The main production defect in laminating tunnels is solvent popping when the first drying zone exceeds 65 °C, producing pinholes that are often undetected until metallization; the corrective action is to reduce the first-zone temperature and increase the third-zone residence time by 20%.

Polyolefin Compounding and Impact Modification Metrics

Compounding ELVAX 3170SHB into polypropylene sheet formulations requires balancing impact modification against a measurable loss in flexural modulus. In extruded and injection-moulded polyolefin compounds, the EVA is added at 5–15 wt% of the PP matrix; at 10 wt%, notched Izod impact energy per ISO 180 increases relative to neat PP, while tensile strength per ISO 527-2 and flexural modulus per ISO 178 follow a near-linear dilution curve with increasing EVA content. Compounders use co-rotating twin-screw extruders with L/D 44:1, barrel zones 190–210 °C, die temperature 205 °C, vacuum venting at −0.08 MPa, and strand pelletizing; melt temperature is kept below 210 °C because prolonged residence above this threshold promotes acetic acid evolution and corrosion on standard nitrided screw and barrel surfaces. The EVA component forms a co-matrix phase with domain sizes in the 1–5 µm range after twin-screw dispersion, but published data for the exact phase morphology of ELVAX 3170SHB in heterophasic PP at 5 wt% loading is limited; process validation therefore requires differential scanning calorimetry for co-crystallinity and scanning electron microscopy of cryofractured samples. Regulatory compliance for electric and electronic appliance compounds is anchored to REACH and RoHS 2011/65/EU, with heat distortion temperature, tensile, and flammability reporting under ISO 75-2, ISO 527-2, and UL 94 where contractually specified. Terminal finished products include automotive interior trim retainers, appliance housing gaskets, extruded sheet for dunnage trays, and polypropylene edge-banding that requires improved low-temperature embrittlement resistance. The most common production bottleneck on twin-screw lines is strand breakage when the EVA phase is inadequately dispersed; the corrective procedure is to feed EVA granules through the main hopper with PP rather than through a side stuffer, because side-arm feeding below 190 °C increases ungelled polymer agglomerates at the strand die.

Crosslinked EVA foam sheet production for closed-cell cushioning starts with ELVAX 3170SHB charged at 100 phr as the base polymer in an internal mixer running at 105–115 °C and 40–50 rpm, with dicumyl peroxide at 0.8–1.2 phr, azodicarbonamide at 4–6 phr, zinc oxide at 1–2 phr, and zinc stearate at 1–2 phr; the peroxide initiates crosslinking while the blowing agent decomposes to generate the closed-cell structure, so the ratio of peroxide to azodicarbonamide is the principal formulation lever for density and tear strength. After discharge onto a two-roll mill at 90–100 °C, the sheet is hot-pressed or continuously vulcanized at 165–175 °C under 10–15 MPa for 8–12 min; shifting the press temperature from 170 °C to 175 °C shortens the peroxide half-life and can trap gas when blowing agent decomposition lags crosslinking, producing internal splits that appear only after demolding. The expanded sheet is matured at 40–60 °C for 24–48 h before die cutting because immediate conversion can produce width shrinkage of 2–4%. Compliance for footwear and sports mat applications falls under REACH, and for articles marketed to children under Directive 2009/48/EC with specific attention to formamide release from azodicarbonamide; physical property reporting follows ASTM D3575 for flexible cellular olefin materials and ISO 1798 for tensile and elongation of flexible cellular polymeric materials. Terminal finished products include athletic shoe midsoles, sandal soles, anti-fatigue mats, protective packaging inserts, and reusable sports rollers. The most frequent production defect in sheet foam plants is density variation across the platen caused by hot-spot deviations of ±5 °C, which can change foam density by up to 0.25 g/cm³ between centre and edge positions; thermal mapping of the press and reduced ram pressure during the initial 30 s of blowing are used to narrow this distribution.

When Bituminous Waterproofing Membranes Demand Low-Temperature Flexibility

During production of polymer-modified bitumen waterproofing membranes, ELVAX 3170SHB is added at 3–6 wt% of bitumen to improve low-temperature flexibility and reduce cold-flow relative to straight-run bitumen; self-adhesive membrane compounds may use 8–10 wt% only when filler loading is reduced to manage process viscosity. The polymer is dispersed in a high-shear rotor-stator mill or colloid mill at 170–180 °C with rotor tip speed above 15 m/s and circulation times of 45–90 min; the modified bitumen is then compounded with 20–30 wt% calcium carbonate filler and coated onto polyester or glass-fibre reinforcement at 140–160 °C. Storage stability is evaluated at 160 °C for 72 h using the sampling and physical test framework of ASTM D5147 or the plant-specific equivalent, with ring-and-ball softening point and low-temperature flexibility measured before and after storage; published data for the exact storage stability of ELVAX 3170SHB-modified oxidised bitumen at 6 wt% is limited, so each plant quantifies phase separation through the difference in softening point after storage. Compliance for roofing membranes is anchored to EN 1109 for low-temperature flexibility, ASTM D5147 for modified bituminous sheet sampling and testing, and Regulation (EU) No 305/2011 for CE marking of construction products. Terminal finished products include torch-applied polyester-reinforced roofing membranes, bridge deck waterproofing layers, self-adhesive bituminous flashing tapes, and below-grade tanking sheets where cold-temperature crack bridging is specified. A processing limitation in modified-bitumen lines is the balance between high-shear polymer dispersion and thermal oxidation of the bitumen; extended stirring beyond 90 min at 180 °C increases softening point drift and can embrittle the final membrane enough to reduce crack-bridging capacity.