PP+LGF40 Long Glass Fiber Reinforced Polypropylene

High-Stiffness Lightweight Structural Material for Automotive & Industrial Applications

In the development of automotive lightweighting, chassis structures, battery pack brackets, and large load-bearing structural components, PP+LGF40 (40% Long Glass Fiber Reinforced Polypropylene) is classified as a highly filled long glass fiber modified polyolefin material.

With its ultra-high stiffness, excellent creep resistance, high load-bearing capability, and lightweight properties, it can replace certain PA6-GF30 structural components.

This article systematically analyzes the material from multiple dimensions, including material definition, composition performance, overall characteristics, injection molding process, typical applications, and mechanical properties, providing valuable reference for automotive material selection and structural design.

1. Material Definition

PP+LGF40 is a high-performance structural plastic based on copolymer polypropylene reinforced with 40% long glass fiber. Compared with PP+LGF20, the higher glass fiber content provides comprehensive improvements in stiffness, strength, fatigue resistance, and creep resistance.

Compared with conventional short glass fiber PP+GF materials, the long fibers maintain a continuous entangled structure, resulting in superior long-term load-bearing capability and dimensional stability.

Core Material Positioning

A high-stiffness, medium-load lightweight structural material suitable for components requiring high modulus, creep resistance, long-term static load performance, and lightweight replacement of nylon-based materials.

2. Core Performance Advantages

Mechanical Properties

Tensile modulus: 5500–6500 MPa
Tensile strength: 55–65 MPa
Excellent creep resistance
Outstanding fatigue performance
Improved low-temperature impact resistance

Dimensional Stability

Density: 1.05–1.10 g/cm³
Very low water absorption
Low molding shrinkage
High dimensional accuracy
Reduced warpage in large parts

Chemical Resistance

Acid & alkali resistance
Salt spray resistance
Oil & antifreeze resistance
Excellent electrical insulation
Suitable for EV battery structures

3. Inherent Material Limitations

Visible floating fibers on the surface due to high glass fiber loading.
Not suitable for high-gloss appearance parts.
Impact toughness decreases as glass fiber content increases.
Long-term heat resistance lower than PA6-GF30.
Excessive injection shear can break long fibers.
Higher screw and mold wear compared with standard PP.

4. Injection Molding Parameters

Parameter	Recommended Range
Drying Temperature	75–85°C
Drying Time	1.5–2.5 Hours
Feed Zone	185–195°C
Middle Zone	195–215°C
Nozzle Temperature	205–225°C
Mold Temperature	35–60°C

5. Typical Applications

Automotive Industry

Battery pack underbody shields
Battery module brackets
Chassis reinforcement structures
Seat support systems
HVAC support brackets
Rear trunk reinforcement frames

Industrial Equipment

Industrial machine bases
Heavy-duty logistics structures
Mechanical support beams
Corrosion-resistant brackets
Conveyor load-bearing frames
Pump & valve support bases

7. Material Summary

PP+LGF40 is a high-performance structural material based on highly filled long glass fiber reinforced polypropylene. It offers outstanding advantages including high modulus, high load-bearing capability, excellent creep resistance, low moisture absorption, lightweight properties, and cost efficiency.

It can widely replace PP+LGF20 in high-load applications and can also substitute PA6-GF30 in non-high-temperature environments to achieve both weight reduction and cost reduction.