INZEA F29 HT G30 is a rigid injection molding compound composed of a high-temperature polylactic acid matrix compounded with 30% by weight glass fiber. The grade is intended for technical parts requiring elevated heat deflection and dimensional stability under load. The PLA matrix is industrial compostable under EN 13432:2000, but the 30% glass fiber reinforcement remains an inert mineral fraction; the full compound is therefore not equivalent to an unfilled biodegradable PLA grade. The property ranges in the following table are representative for glass-filled high-temperature PLA injection molding compounds, not certified lot-specific values, and must be confirmed against the manufacturer’s certificate of analysis.

Injection Molding Boundaries for a Glass-Filled High-Temperature PLA

Drying must be performed in a desiccant dryer with a dew point of −40 °C or lower. The pellets are dried at 80 °C for 4–6 h; moisture content above 0.02% by ISO 15512:2019 initiates hydrolytic chain scission in the PLA matrix and produces melt flow drift, splay, and loss of mechanical strength. A reciprocating screw injection molding machine with medium shear geometry and a screw length-to-diameter ratio of 20:1 to 25:1 is preferred. Melt temperature is limited to 195–215 °C. Above 225 °C, depolymerization of PLA accelerates and the melt flow rate shifts upward; below 190 °C, melt homogeneity is insufficient and screw torque becomes unstable because of the 30% glass fiber fraction.

On production lines using clamp forces in the 80–120 t range, the 30% glass fiber content creates anisotropic shrinkage and weld-line weakness. Fiber orientation near knit lines can reduce weld-line tensile strength by 20–40% relative to bulk tensile strength. Mold temperature is the dominant processing variable for heat resistance: below 85 °C, the high-heat PLA matrix does not develop sufficient crystallinity, and the HDT B can fall by 30–40 °C compared with parts molded at 100–110 °C. Hot runner systems should use externally heated manifolds and valve gates; cold sprues and runners should be kept short because the glass-filled melt solidifies rapidly in narrow channels.

When 30% Glass Fiber Shifts From Toughening to Embrittlement

Compared with unfilled INZEA F29 HT, the 30% glass loading in F29 HT G30 produces a step change in load-bearing capacity. Tensile modulus increases from approximately 3000–3800 MPa for unfilled high-temperature PLA to 7500–9500 MPa for the glass-filled grade, while tensile elongation at break falls from roughly 4–6% to 1–2%. This is a property cliff-edge: the filled grade becomes a rigid, low-elongation material with limited plastic deformation before fracture. Charpy unnotched impact strength remains moderate at 15–25 kJ/m² by ISO 179-1:2020, but the material should not be specified for snap fits or live hinges unless generous radii and low strain conditions are designed in.

The high glass fraction also changes processing economics and tooling behavior. Screw and barrel surfaces experience accelerated abrasive wear; bimetallic hardened barrels, nitrided screws, and replaceable check rings are specified. Mold maintenance intervals are shortened relative to unfilled PLA because glass fiber can erode gate inserts and ejector pin bores. In thin-wall sections below 2 mm, the combined effect of rapid solidification and high melt viscosity may lead to short shots if injection speed is not raised. At the same time, excessive injection speed creates shear heating at the gate, which can locally exceed the 225 °C depolymerization threshold and generate splay or brown streaks.

What Else Changes When the Matrix Is Biodegradable but the Reinforcement Is Not?

The PLA matrix fraction remains biodegradable under industrial composting conditions according to EN 13432:2000 and ISO 14855-1:2020, but the 30% glass fiber reinforcement does not mineralize. Published data for this specific glass-filled PLA configuration under ISO 20200:2015 or EN 17033:2018 is limited; compostability assessments for such compounds generally apply only to the polymer matrix after mechanical size reduction. The glass fiber fraction remains as a solid residue in compost screening and can reduce the final compost quality unless separation or a dedicated waste stream is used. This differs from unfilled INZEA F29 HT, which is more readily classified as industrially compostable because it contains no persistent mineral reinforcement.

The material differs from polyhydroxyalkanoate molding grades in mechanical response and thermal boundaries. PHA compounds often show lower tensile modulus and higher elongation than glass-filled PLA, but their melt processing window is narrower and their odor and crystallization behavior require different mold cooling strategies. Compared with petroleum styrenic grades such as ABS, INZEA F29 HT G30 offers a renewable polymer matrix and higher heat deflection potential under crystallizing mold conditions, but with lower ductility and a more restricted processing envelope. For food-contact applications, the PLA matrix may be evaluated under EU Regulation 10/2011 or FDA 21 CFR 177.1520, while the glass fiber sizing and coupling system require separate suitability verification for direct food contact. REACH and RoHS compliance should be confirmed for the specific lot, especially for sizing agents, mineral fractions, and any processing aids.

The grade is not intended for blow molding, film extrusion, or thermoforming. Its 30% glass fiber content reduces melt strength and increases die wear in continuous extrusion processes. The compound is designed for rigid injection molded parts requiring high stiffness, dimensional stability, and resistance to short-term heat exposure, provided the part design accepts low elongation at break and the processing equipment is configured for a filled high-temperature PLA.