ELVAX 3135SB Copolímero de acetato de etileno e vinil

ELVAX 3135SB is an ethylene vinyl acetate copolymer supplied in pellet form with a nominal vinyl acetate comonomer content of 12% by weight, a melt flow rate of approximately 0.35 g/10 min under ISO 1133-1:2022, and a density near 0.933 g/cm³ under ISO 1183-1:2019. The low melt flow rate imposes specific mixing and pumping requirements in downstream equipment, while the 12% vinyl acetate content provides a balance of polarity, heat-seal response, and compatibility with polyolefins that differs from high-vinyl-acetate EVA grades. The following application scenarios are limited to downstream processes where such a low-MFI, low-VA grade is documented in industrial practice; published data for configurations outside these boundaries is limited.

In three-layer coextruded food-contact films, ELVAX 3135SB is processed as the sealant skin layer because the 12% vinyl acetate comonomer content disrupts polyethylene crystallinity sufficiently to reduce seal initiation temperature while retaining sufficient melt strength for bubble stability at a melt flow rate of 0.35 g/10 min. The formulation addition ratio in the sealant layer is typically 60–80 wt% ELVAX 3135SB with 20–40 wt% linear low-density polyethylene having a melt index of 1.0–2.0 g/10 min; the LLDPE fraction is adjusted upward when hot-tack strength must be maintained above 120°C. Downstream production is performed on three-layer blown-film lines with die gap 1.8–2.4 mm, melt temperature 190–215°C, and blow-up ratios between 2.0:1 and 2.8:1. Because ethylene vinyl acetate liberates acetic acid at elevated temperatures, residence time above 240°C is limited to less than 10 minutes, and chromium-plated die lips are preferred to reduce corrosion. Food-contact compliance is governed by FDA 21 CFR 177.1350 for ethylene-vinyl acetate copolymers and Commission Regulation (EU) No 10/2011, with overall migration testing at 10 mg/dm² and specific migration limits for vinyl acetate monomer. Terminal product types include frozen food lidding film, cheese overwrap, stand-up pouch inner sealant webs, and non-sterile medical device pouch sealant layers where the EVA is not the fluid-contact layer.

What Limits Low-Shear Dispersion When 12% Vinyl Acetate Copolymer Is Melt-Blended Into Bitumen?

Low-shear paddle agitation is insufficient for dispersing ELVAX 3135SB into oxidized bitumen because the polymer domain size remains above 100 µm unless a high-shear rotor-stator mixer or an inline colloid mill is used at temperatures above 160°C. In modified bitumen waterproofing compounds, ELVAX 3135SB is metered at 3–6 wt% of the total compound, with the balance being oxidized bitumen, calcium carbonate filler, and in some formulations 2–5 wt% atactic polypropylene. The production process uses a high-shear mixing vessel at 175–185°C under nitrogen blanket for 60–90 minutes, followed by feeding to a carrier saturation line where polyester or glass-fiber mat is saturated at 35–55 m/min and cooled below 35°C before winding. Low-temperature flexibility and high-temperature flow resistance are measured under ASTM D5147-18, while the finished membrane is evaluated under EN 13707:2004+A2:2018 for flexible sheets for waterproofing; dimensional stability is tested under EN 1107-2. Terminal product types include torch-applied polymer-modified bitumen membranes, bridge-deck waterproofing underlays, and self-adhesive roofing repair tapes.

On high-torque twin-screw compounding lines with L/D ratios of 40:1 to 52:1, ELVAX 3135SB functions as a carrier resin for white masterbatches and processing-aid concentrates because its low melt flow rate contributes to high melt-mixing viscosity and lower migration of liquid additives in pelletized concentrates. The carrier addition level in masterbatch formulations commonly falls between 20 wt% and 50 wt%, with titanium dioxide loadings of 50–70 wt% in white concentrates and the remainder functional additives such as erucamide or zinc stearate; specific screw profiles using two- and three-lobe kneading blocks are required to disperse TiO₂ without overworking the carrier. Pelletizing is conducted by strand water-bath cooling and rotary cutting; barrel temperatures are held at 160–190°C with a die plate temperature of 170–185°C. Compliance for masterbatches supplied into the EU packaging chain is assessed under Regulation (EC) No 1935/2004 for food contact materials, Regulation (EU) No 10/2011 for plastic food contact articles, and Directive 2011/65/EU for RoHS-restricted substances. Terminal product types include polyethylene stretch-film white masterbatch, anti-block concentrates, and polymer processing-aid masterbatch for polyolefin film extrusion.

Polyolefin modification for durable semi-flexible profiles

Addition of ELVAX 3135SB to high-density polyethylene or linear low-density polyethylene at 10–30 wt% lowers flexural modulus and improves stress-crack resistance in extruded profiles used for edge protection, appliance sealing, and closure liners. The polymer blend is compounded on a corotating twin-screw extruder at barrel temperatures of 170–200°C, then pelletized and fed to a single-screw profile extrusion line with vacuum calibration and cutting. Operational boundaries include the lower thermal stability of EVA relative to polyethylene under prolonged heating: processing temperatures should not exceed 230°C for extended residence times, and peroxide-containing concentrates must be avoided unless the profile is intended for crosslinking. Compliance for non-food industrial profiles is verified against REACH and Directive 2011/65/EU, with mechanical testing under ISO 527-2 for tensile properties, ISO 178 for flexural properties, and ASTM D1693-15 for environmental stress crack resistance. Terminal products include machinery edge guards, agricultural sheet fastening profiles, and appliance gaskets.

When compression-molded crosslinked foam formulations incorporate ELVAX 3135SB, the low melt flow rate of 0.35 g/10 min acts as a viscosity buffer during gas expansion, reducing cell coalescence when the blowing agent decomposes. The formulation addition ratio is given in the table below; typical ranges are 40–60 wt% ELVAX 3135SB, 40–60 wt% LDPE, 2.5–4.0 phr azodicarbonamide, 0.6–1.0 phr dicumyl peroxide, and 0.5–1.0 phr zinc oxide. Mixing on a two-roll mill at 105–115°C is required to avoid premature decomposition of azodicarbonamide, which initiates near 195–205°C depending on particle size. Crosslinked foam boards are compression molded at 150–165°C under 10–15 MPa, followed by free expansion at 160–170°C. Physical properties are tested under ISO 1798 for tensile strength and elongation, ISO 844 for compression set, and flammability under FMVSS 302 where automotive interior trim is involved. Terminal product types include anti-fatigue mats, industrial padding, and expansion joint filler boards.

When the resin is used as a wax-modifying additive for paraffinic coatings and candle compounds

When the resin is used as a wax-modifying additive for paraffinic coatings and candle compounds, ELVAX 3135SB is added at 1–5 wt% of the total wax compound to reduce mottling, increase blocking resistance, and raise congealing point. The production process consists of a stirred wax melt at 100–120°C with moderate agitation, followed by cooling under continuous agitation to 60–70°C and casting into slabs or pastilles. Quantitative published data for this specific grade in candle compounds is limited; industrial practice uses the lower addition range for coating waxes and the upper range for high-wax candle blends. Compliance is tested under ASTM D938-21 for congealing point and ASTM D1321-19 for needle penetration of petroleum waxes, with classification and labeling under Regulation (EC) No 1272/2008. Terminal product types include industrial wax coatings for corrugated board, candle compounds, and wax-based adhesives for paper bonding.