Avient Polystrand ThermoPro™ IE7010 Unitape is a continuous unidirectional E-glass fiber reinforced polypropylene thermoplastic composite supplied as a consolidated tape. The nominal fiber loading is 60% by weight, the nominal tape thickness is 0.25 mm, and the density is 1.49 g/cm³ when measured according to ASTM D792. In the fiber direction, supplier-published tensile strength is approximately 517 MPa and tensile modulus is approximately 27.6 GPa, both determined according to ASTM D3039; flexural strength and flexural modulus are approximately 690 MPa and 24.1 GPa, respectively, according to ASTM D790. The product is a fully thermoplastic unidirectional sheet, not a thermoset prepreg, and it contains no reactive styrene or epoxy hardener.

The unidirectional architecture places continuous glass rovings parallel to the longitudinal machine axis within a polypropylene matrix, creating pronounced mechanical anisotropy. The supplier-published values below are representative data and are not design allowables unless independently verified on production coupon stock.

What Processing Window Governs Thermoforming and Lamination of IE7010?

The polypropylene matrix begins to melt at approximately 165 °C and is typically consolidated at 180–210 °C. At platen or belt temperatures below 175 °C, melt viscosity is too high for complete wet-out of thick tape stacks, and interlaminar void content can remain above 3% when measured by ASTM D2734. At temperatures above 230 °C, oxidative degradation of the polypropylene matrix can occur within several minutes, producing a measurable reduction in melt flow rate when tested according to ISO 1133-1:2022. Double-belt lamination lines operated at belt temperatures of 190–205 °C and nip pressures of 0.5–1.5 MPa can reduce void content below 2% at line speeds of 2–6 m/min. Line speed must be reduced when laminate thickness exceeds 5 mm because the glass fiber bed acts as an insulator and slows heat transfer into the core layers.

In compression molding, heated platens at 190–210 °C and molding pressure of 0.5–2.0 MPa are applied after the tape stack reaches core temperature. Tool surfaces below 120 °C can cause premature freeze-off of the matrix and incomplete edge replication. Silicone-based mold release systems should be avoided when post-molding painting or adhesive bonding is required because silicone migration to the surface reduces adhesion. Roll tension during unwinding of 0.25 mm tape should be kept below 5 N/cm; higher tension can split the tape along fiber bundles because transverse tensile strength is below 25 MPa.

High-humidity storage does not plasticize the polypropylene matrix, which absorbs less than 0.01% moisture by ISO 62, but condensation on cold tape surfaces can disrupt fiber wet-out. Conditioning tape at 23 °C and 60% relative humidity for 24 h before processing avoids condensation defects in facilities with uncontrolled temperature swings.

On production-scale double-belt lines, the primary bottleneck is often roll handling rather than consolidation. Unidirectional tape has almost no transverse strength; edge nicks generated by slitting or by contact with misaligned guides propagate as longitudinal splits during tension changes. Lay-up tables with vacuum hold-down and low-tension dancer rolls reduce waste. In insert overmolding, the tape insert is heated by infrared ovens to a surface temperature of 150–170 °C before transfer to an injection mold at 40–80 °C; the polypropylene overmolding resin at 230–250 °C melt temperature provides local reflow at the interface. Clamp force is selected to pack the overmolding resin without crushing the consolidated tape insert, typically 3–5 kN per projected cm² of part area, although machine-specific optimization is required.

When Unidirectional Tape Replaces Short-Glass Injection Molding Feedstock

A short-glass polypropylene compound at 30 wt% glass typically exhibits tensile strength of 80–100 MPa and tensile modulus of 5–6 GPa by ASTM D638. IE7010 at 60 wt% continuous glass provides approximately 517 MPa and 27.6 GPa in the fiber direction by ASTM D3039, roughly five times the tensile modulus at two times the glass content. This comparison is direction-specific; transverse tensile strength of IE7010 is below 25 MPa, whereas short-glass compounds remain substantially isotropic. Consequently, IE7010 is not a direct drop-in for isotropic injection molding grades. Structural parts made from IE7010 require 0/90 cross-ply or quasi-isotropic laminate construction to resist multi-axial service loads. Selective reinforcement is the more common integration method: continuous unidirectional tape is placed in the primary load path, while overmolded short-glass polypropylene forms ribs, bosses, and attachment features.

What Separates IE7010 from Epoxy Prepreg and Woven Organosheet Formats?

Because the matrix is thermoplastic, IE7010 has no B-stage, no exothermic cure, and no refrigerated shelf life. It can be reheated repeatedly, allowing splicing and co-consolidation with additional polypropylene layers. Unlike epoxy prepreg, which typically requires autoclave pressure and vacuum bag debulking, IE7010 is consolidated in a hot press or double-belt lamination line with pressures below 2 MPa. The trade-off is thermoplastic behavior at elevated temperature; sustained load-bearing applications above 90 °C should be validated by creep testing to ISO 899-1. Compared with woven glass-polypropylene organosheet, IE7010 has higher unidirectional stiffness because the fibers are uncrimped. A 0/90 woven fabric introduces fiber crimp that can reduce effective modulus by 10–20% relative to a cross-ply unidirectional tape laminate with the same areal glass content. Woven organosheet handles better during drape and has higher transverse integrity in the fabric plane; IE7010 can split along the fiber direction when formed around tight radii. Blank design must include trim allowances and avoid features that generate transverse tension at the blank edge.

Automotive load floors, underbody shields, battery protective covers, and door module carriers are typical applications for polypropylene-based unidirectional tape. A quasi-isotropic laminate with 50–60% continuous glass content provides bending stiffness and mass reduction when compared with steel or aluminum sheet at equivalent panel geometry; the exact mass delta depends on ribbing and section shape. Polypropylene-based composites are normally classified HB at 3.0 mm in UL 94; vertical burn ratings require flame-retardant modification of the matrix. Because no reactive diluent or solvent is present in the matrix, volatile emission levels are generally low, but emissions from additives and surface treatments should be verified by VDA 277 or VDA 278 where automotive interior criteria apply.

Flame Treatment and Surface Energy Requirements for Adhesive Bonding

Polypropylene has a surface energy typically near 30 mN/m, below the 44–48 mN/m range required for reliable structural adhesive wetting. Flame treatment or corona discharge should raise surface energy to at least 48 mN/m before bonding with methyl methacrylate, polyolefin adhesive, or structural tape. Lap shear strength can be measured by ASTM D3163; after proper activation, failure often occurs in the tape transverse direction rather than at the adhesive interface. For in-mold painting, a polypropylene-compatible adhesion promoter or film treatment is required because the nonpolar matrix resists conventional solventborne primers. If silicone mold release was used, surface activation alone is often insufficient; mechanical abrasion or solvent cleaning may still leave low-energy silicone residues that reduce bond durability.

Because the matrix is polypropylene, IE7010 should not be specified for sustained static load above 90 °C without creep validation, nor for continuous immersion in aromatic hydrocarbons or strong oxidizing acids. Differential thermal expansion is inherent: longitudinal thermal expansion is governed by glass and is typically 6–10 ppm/°C, while transverse expansion is governed by polypropylene and can exceed 100 ppm/°C. Asymmetric laminates can warp when cooled from molding temperature because of this mismatch, so tooling design should account for post-mold shape correction. Cut edges expose glass filaments and should be sealed by overmolding or edge tape in wet service. Regrind from trimming is thermoplastic and recoverable, but the fiber length is reduced to short-glass dimensions and is therefore suitable only as replacement for short-glass polypropylene compound, not for continuous tape applications.