Elvaloy PTW

Description

Elvaloy® PTW is a reactive terpolymer of ethylene, n-butyl acrylate and glycidyl methacrylate (E/n-BA/GMA) developed by DuPont (now Dow) specifically as a reactive impact modifier for engineering polymers with ester or amide functionality: PA (polyamides), PBT (polybutylene terephthalate) and PET (polyethylene terephthalate). The PTW designation stands for Polymer Toughener with Worldwide approval (international certification for food contact).

Key feature: the epoxy group of the glycidyl methacrylate unit (~8 wt % GMA) reacts chemically with the end groups of PA (-NH₂, -COOH) or the ester linkages of PBT/PET during compounding at 250–280 °C. This creates a grafted copolymer interphase between the matrix and the elastomer phase, improving adhesion and dispersion — considerably more effective than mechanical blending with a non-reactive elastomer (EPDM, SEBS).

Effect on the final matrix: +200–500 % impact strength at 10–20 % Elvaloy® PTW loading in PA, PBT or PET with minimal loss of stiffness (vs non-reactive modifiers, where the stiffness loss is 30–50 %). This has made Elvaloy® PTW the industry standard for super-tough polyamide and PBT grades.

Typical parameters: GMA content ~8 wt %, n-butyl acrylate content ~28 %, ethylene ~64 %, MFR ~12 g/10 min (190 °C / 2.16 kg), density 0.94 g/cm³, melting temperature Tm ~70 °C, Vicat softening temperature 47 °C, Shore A hardness ~85, elongation at break >500 %.

Key advantages

• Reactive impact modification of PA/PBT/PET — the only modifier class that grafts chemically onto the matrix end groups (vs mechanical blending)
• +200–500 % impact strength at 10–20 % loading — typical reinforcement for super-tough grades (PA66 + 15% PTW = notched impact strength of 80–120 kJ/m² vs ~5–6 for unmodified PA66)
• Minimal loss of stiffness compared with non-reactive modifiers thanks to interfacial adhesion
• Good resistance to hydrolysis and heat ageing — critical for PBT/PET applications
• FDA / EU 10/2011 compliance for food contact (PTW = Worldwide approval)
• Suitable for recycled PET — Elvaloy® PTW restores the molecular chain length of degraded rPET through epoxy coupling
• Stability at high compounding temperatures (250–290 °C) — does not scorch in the screw
• Flexible dosing — from 2 % (umbrella-effect tackifier) to 25 % (super-tough)

Applications

• Super-tough polyamides (PA6, PA66, PA610): compounds with non-break unnotched impact strength (>200 kJ/m²) — for airbag clips, snap-fit hardware and fasteners with critical impact loads at −40…+80 °C
• Impact modification of PBT: for automotive connectors, electric-vehicle charging systems and consumer electronics — higher impact strength without loss of dielectric properties
• PET bottle-grade upgrading: adding 1–3 % Elvaloy® PTW to bottle-grade PET for cold climates (winter retail at −20 °C) — reduced brittleness
• Compatibilizer for PA/PE blends: a bridge between incompatible PA and PE matrices for hybrid multilayer packaging and technical compounds
• Recycled PET / rPET upgrading: restoring the intrinsic viscosity of degraded rPET — moving from mechanical to reactive recycling
• Road construction and roofing mastics: bitumen modifier with improved adhesion to mineral aggregates
• Hot-melt adhesives for thermoplastics: connection-bridge adhesive between an EVA matrix and PA/PET films

Limitations

• The reactivity with PA/PBT/PET is a feature, but it also requires precise control of the compounding temperature (250–280 °C; higher — GMA degradation, lower — insufficient grafting)
• Incompatible with matrices without active functional groups (PE, PP) unless an additional compatibilizer is used
• Price is 3–5 times higher than non-reactive impact modifiers (EPDM, SBS, SEBS) — justified only for critical super-tough applications
• The epoxy function is moisture-sensitive — the matrix must be dried before compounding

Global market counterparts: Arkema Lotader® AX8840 (E/MA/GMA), SK Functional Polymer Bondyram® 7103 (E/BA/GMA), Mitsubishi Modiper® A4400 (E/GMA), BASF Joncryl® ADR (GMA-based chain extenders, a narrower niche). Elvaloy® PTW is the original DuPont / Dow grade with the longest application history and the most accessible technical support.

The stated values are measured using in-house methods close to the corresponding ISO, ASTM and GOST standards. This information is for reference only and does not constitute an official batch data sheet. Please request the TDS and MSDS for the specific batch before industrial use.