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The Complete Guide for Pultruded Profiles

Pultruded profiles, as a type of designable reinforcement material, are increasingly being applied in various fields.
Whether you want to use pultruded profiles,sush pultruded graring,pultruded rod,or pultruded deck,you will need to know some techniqes to pultruded profiles.
In this guide, you are going to get how to produce the pultruded profiles,and how to choice the right material for the pultruded profiles,how to design the pultruded profile,just to mention a few.
So, as a pultruded profile fabricator who wants to gain more knowledge in the composite fabrication industry – this is the right guide for you.

Pultrusion Process

pultrude profile manufacturer process

Pultrusion is a production process for fiber-reinforced plastics (FRP or GRP). It is characterized by being continuous and reliable. In short, the pultrusion process involves pulling reinforcing materials (glass fiber, carbon fiber, or aramid fiber) through equipment, passing them through a liquid polymer, typically various types of resin, and then through a mold for curing and cooling. The result is a product with a consistent cross-sectional shape, which is what we refer to as “pultrusion.”

Pultruded Profile Manufacturing Process

The pultrusion process generally includes the laying of glass fiber roving, impregnation, and passing the resin-impregnated glass fiber roving through a mold for curing, followed by cutting into the required products.

Pultrusion Equipment Components

  • Generally, we lay out our reinforcing materials according to the needs of the pultruded profile, such as glass fiber roving, mat, and carbon fiber. The main requirements include roving racks, mat racks, etc.
  • Resin Impregnation Tank: Typically, pultruded profiles use an open resin tank for easy resin addition and operation. We generally require that the fibers and mats are neatly arranged throughout the impregnation process.
  • Preforming Section: The impregnated reinforcing materials pass through a yarn board. The role of preforming is to ensure that each yarn is in its relative position, gradually approaching the final shape of the product, and extruding excess resin for curing in the mold.
  • Mold: The mold is crucial in the pultrusion process. Different resin systems require different design conditions and manufacturing requirements for molds. Typically, the mold cavity surface is chrome-plated to enhance mold hardness and reduce friction. The lengths of molds are usually 700mm, 900mm, 1000mm, and 1200mm. Based on the resin curing exothermic curve, the mold is divided into three different heating zones, with temperatures adjusted according to the resin system’s performance and the pultrusion speed. A good mold can have a lifespan of up to 300,000 meters.
  • Pultrusion Machinery: Generally, the traction equipment is divided into mechanical and hydraulic reciprocating types. Small and simple products usually use mechanical traction equipment, while large and complex products use hydraulic reciprocating pultrusion equipment. The function of the traction equipment is to ensure that the profile can be steadily and continuously pulled out of the mold.
  • Cutting Device: The pultruded profile is cut into the required lengths.

Pultruded Profile Materials

Resin

Typical pultruded products consist of various glass fibers, resins, and some auxiliary materials.
Resin Matrix
Pultruded profiles mainly use thermosetting resins, such as unsaturated polyester resin, vinyl ester resin, and other resins like phenolic resin, epoxy resin, and polyurethane resin.

  1. Polyester Resin:The most commonly used resin type in pultrusion, with good mechanical properties, chemical resistance, and cost-effectiveness.
  2. Vinyl Ester Resin:Better corrosion resistance and mechanical properties. Pultruded profiles made with vinyl ester resin can be used in corrosive conditions.
  3. Epoxy Resin: Typically used in fiberglass pultruded profiles for high-voltage insulation products. It can withstand high voltages, with low shrinkage, high mechanical properties, and excellent adhesion to fibers. Epoxy resin can be used with carbon fibers to produce products requiring high strength and durability, such as in the aerospace and automotive industries.
  4. Phenolic Resin:Known for its excellent fire resistance and low smoke production, making it ideal for applications with high fire safety requirements.
  5. Polyurethane Resin:Known for its high toughness and relatively high rigidity, polyurethane pultruded profiles are suitable for applications requiring high structural performance.

Fiber Reinforcement Materials

fiberglass roving

The fiber reinforcement materials used in pultruded FRP are mainly E-glass fiber roving. Depending on the product requirements, C-glass fiber and other synthetic fibers like carbon fiber may also be used. Various continuous fiber mats or fabrics are also selected to enhance the transverse strength of the product.
E Glass Offers good mechanical properties and cost advantages, making it the most commonly used.
Here is the information presented in a table format:

Property Value
Tex Values 2400tex, 4800tex, 9600tex
Density 2.54 g/cm³ (158.6 lbs/ft³)
Tensile Strength 3,400 MPa (490 ksi)
Elastic Modulus 72 GPa (10,440 ksi)
Percentage Elongation 4.7%

E-glass achieves a good balance between performance and cost, with excellent strength and stiffness, as well as good chemical resistance, moisture resistance, and thermal resistance. It was developed specifically for electrical applications,hence its excellent insulating properties. Typical uses include aerospace components, marine and recreational equipment, and general industrial parts.
Carbon Fiber Used in pultruded profiles, carbon fiber offers high strength, good stiffness, and lightweight characteristics.

Property Value
Tensile Strength 250 ksi (1.72 GPa)
Tensile Modulus 20 msi (138 GPa)
Ultimate Shear Strength 6.0 ksi (41.3 MPa)
Ultimate Tensile Strain 1.5%
Flexural Strength 265 ksi (1.83 GPa)
Flexural Modulus 19 msi (131 GPa)
Coefficient of Thermal Expansion (CTE) -0.1 ppm/ºF (-0.2 ppm/ºC)
Density 0.054 lbs/in³ (1.5 g/cm³)

Auxiliary Materials

Initiators

Commonly used initiators include:

  • MEKP (Methyl Ethyl Ketone Peroxide): An organic peroxide typically used in unsaturated polyester resin systems.
  • TBPB (Tert-Butyl Peroxybenzoate): A liquid organic peroxide that can increase the curing speed of pultruded profiles.
  • BPO (Benzoyl Peroxide): An organic peroxide used as a curing agent for polymers.
  • Lm-P (Special Pultrusion Curing Agent): A special curing agent designed for pultrusion processes.
  • TBPO (Tert-Butyl Peroxyisooctanoate): Similar to TBPB.

Epoxy Resin Hardeners

Common hardeners include anhydrides, tertiary amines, and imidazoles.

Pigments

Pigments in pultrusion are generally in the form of paste.

Fillers

Fillers can reduce shrinkage, improve dimensional stability, surface smoothness, and matte or non-glossy appearance; adjust resin viscosity; meet different performance requirements, enhance wear resistance, improve conductivity and thermal conductivity; most fillers increase impact strength and compressive strength but not tensile strength; improve pigment coloring effect; some fillers have excellent light stability and chemical resistance; and reduce costs. It’s best to have a gradient in filler particle size for optimal use. Surface treatment of fillers is also practiced to increase their usage.

Release Agents

Internal release agents are commonly used, added to the resin at a certain ratio. Their function is to seep out from the resin matrix at a certain processing temperature, diffusing to the surface of the cured product, forming an isolation film between the mold and the product, facilitating demolding.

Characteristics of Pultruded Profiles

Advantages of FRP Profiles

General pultruded profiles have good strength and stiffness, suitable for use in special structural applications. They also have good corrosion resistance, lightweight, high strength (with a density between 1.5-2.0, one-fourth to one-fifth of carbon steel, but with tensile strength far exceeding ordinary steel), and good impact resistance.
Pultruded profiles have good electrical properties, suitable for manufacturing insulating products such as insulating rods, with good dielectric properties and excellent microwave permeability for use in antenna covers.
In addition to the advantages mentioned above, pultruded profiles have a low thermal conductivity, making them excellent insulating materials, only one-hundredth to one-thousandth of metals.

Limitations of Pultruded Profiles

Pultruded profiles also have some limitations. They can only produce products with the same cross-section, and because the products are longitudinally pultruded, they have high longitudinal strength but low transverse strength.

Shapes of Pultruded Profiles

  1. Fiberglass Tubes: The most commonly used pultruded profiles, lightweight, high strength, and corrosion-resistant, suitable for various structural and non-structural applications.
  2. Fiberglass Rods: Have relatively high strength, good electrical insulation properties, and durability, often used in the high-voltage insulation industry.
  3. Fiberglass Flat Bars/Plates: Available in a wide range of widths, with high strength and flexibility, suitable for the construction industry.
  4. FRP Structural Profiles: Designed specifically for structural applications, with high strength, durability, and resistance to environmental factors.
  5. Fiberglass Sheet Piling: Used in construction for soil retention and water barrier applications, with high strength and corrosion resistance.
  6. Fiberglass Gratings: Used for flooring, walkways, and platforms, featuring slip resistance, durability, and low maintenance costs.
  7. Fiberglass Rebars: A corrosion-resistant alternative to steel rebars, used for concrete reinforcement to increase strength and lifespan.
  8. Steel Sheet Piling (U-shaped): Used for retaining walls and soil reinforcement, with high strength and corrosion resistance.
  9. Anchor Bolts: Used for anchoring structures, with high strength and corrosion resistance.
  10. Fiberglass Composite Decking: A lightweight and durable alternative to traditional decking materials, with good weather resistance.
  11. Fiberglass Composite Retaining Walls: Used for retaining soil, with high strength and easy installation.
  12. Fiberglass Roofing Sheets: Lightweight and durable roofing material with good thermal insulation and weather resistance.
  13. Fiberglass Reinforced Plastic (FRP) Ribbed Pipes: Used for various purposes, with high strength and corrosion resistance.
  14. Fiberglass Reinforced Plastic (FRP) Oval Tubes: With a unique shape and high strength, used for structural applications.
  15. FRP Octagonal Tubes: With high strength and a unique shape, used for various purposes.
  16. FRP Tool Handles: Used for tools, a lightweight and durable alternative to traditional materials.
  17. Fiberglass Rectangular Tubes: Used for structural applications, with high strength and lightweight.
  18. Fiberglass Round Tubes: Commonly used in construction and industrial applications due to their strength and durability.
  19. Fiberglass Reinforced Plastic (FRP) Core Tubes: Used for various applications requiring high strength and insulation properties.
  20. Fiberglass Stakes for Plants: Lightweight and durable stakes used for supporting plants and vines.
  21. Fiberglass Snow Stakes: Used for marking boundaries and hazards in snowy conditions, with high visibility and durability.
  22. Fiberglass Tent Poles: Lightweight and sturdy poles used for camping and outdoor activity tents.
  23. Fiberglass Reinforced Plastic (FRP) Pultruded Profiles Flexible Flagpoles for Worship: Flexible and durable flagpoles used for flags in worship and ceremonial occasions.
  24. Fiberglass Rebars: Used for concrete reinforcement, with corrosion resistance and high strength.
  25. Fiberglass Reinforced Polymer Threaded Steel: Similar to fiberglass threaded steel, used for reinforcing concrete structures.
  26. Fiberglass Reinforced Polymer Spiral Columns: Used for architectural and structural applications, with aesthetics and high strength.
  27. Fiberglass Reinforced Plastic (FRP) Rectangular Stirrups: Rectangular stirrups made of fiberglass reinforced plastic, used for reinforcing concrete.
  28. Fiberglass Reinforced Plastic (FRP) Molded Gratings: Gratings made using the molding process, suitable for various applications.
  29. Fiberglass Reinforced Plastic (FRP) High-Load Gratings: Gratings made of fiberglass reinforced plastic, capable of bearing high loads.
  30. Vinyl Seawalls (Z-shaped): A type of vinyl seawall used for coastal protection.

Applications of Pultruded Profiles

Chemical Industry: Due to the chemical industry’s requirement for corrosion resistance, pultruded profiles are widely used in petrochemical industry structures. Square tubes, round tubes, and other structural components are used in pipeline laying, stairs, handrails, operating platforms, and walkways.
Electrical Systems: Polyurethane resin-made FRP cable trays and unsaturated resin-made crossarms are widely used in electrical systems. Rods made with epoxy resin have good insulation properties and are used in ultra-high voltage systems.
Urban Railway Infrastructure: Phenolic resin-made escape platforms are widely used in subways and other public facilities. Unsaturated resin structural components are also used in protective covers, cable trays, generator handrails, operating platforms, and drainage systems.
Construction and Infrastructure: Compared to ordinary carbon steel, pultruded profiles have the advantages of lightweight, high tensile strength, and easy installation on-site. Many buildings are starting to use pultruded profiles, such as roof ridges, trusses, A-frames, space frames, bridge components, corrosion-resistant guardrails, railway crossing handrails, and highway noise barriers.
Roads and Transportation: Pultruded profiles are increasingly used in roads and transportation due to their durability and low maintenance, especially in icy and cold regions. Facilities such as utility poles and traffic signs are increasingly made with pultruded products.
Outdoor Sports Equipment: Pultruded products are used in sports equipment such as arrow shafts, crossbows, paddle shafts, hockey sticks, and golf clubs due to their lightweight, high strength, and good designability.
Tool Industry: High-strength pultruded tubes and rods are used in the manufacturing of tool handles with ergonomic shapes due to their lightweight, high strength, and variety of colors.
Cooling Tower Industry: Pultruded fiberglass is increasingly used in structural components such as supports, beams, columns, handrails, fan chimneys, gratings, walkways, and distribution systems’ pipes and supports due to its corrosion resistance and strength.

Comparison of Pultruded Profiles with Traditional Materials

– Aluminum Products: In applications where weight is a concern, fiberglass products can offer better flexibility and strength, as well as impact resistance and non-conductivity.
– Steel Products: Although pultruded profiles are more expensive than ordinary steel, they can replace steel in corrosive and insulating environments, such as coastal areas, and have good impact resistance.
– Acrylic Products: Fiberglass has higher strength and durability under harsh conditions compared to acrylic products.
– Wood Products: Wood is cheaper but has higher maintenance costs. Pultruded products are increasingly used in fencing and breeding industries due to their better maintenance-free properties.

Installation of Pultruded Profiles

We generally follow the Pre-Standard for Load & Resistance Factor Design (LRFD) of Pultruded Fiber Reinforced Polymer (FRP) and European Standard EN 13706 to ensure that pultruded profiles can be better installed and used in various fields. When we receive a project, we first conduct detailed design and planning, cutting the profiles to the required lengths in the factory according to the needed dimensions.
Pultruded products are generally lightweight and easy to transport. After transportation to the site, pultruded profiles can also be drilled, connected with bolts or rivets, using carbon steel bolts, stainless steel bolts, or BFRP bolts, suitable for environments with electromagnetic interference requirements and corrosion resistance.
Sometimes, when a smooth surface or no holes are required, we use adhesive bonding methods, such as epoxy, polyurethane, or methyl methacrylate adhesives. When considering this method, we take into account environmental factors such as humidity and temperature. We use some molded structural components to connect the various pultruded profiles.

Design of Pultruded Profiles

The primary consideration in using pultruded profiles is to utilize their excellent properties, such as the required mechanical properties, such as tensile strength, flexural strength, and elastic modulus. Then, the appropriate reinforcing fibers and resin systems are selected. Common fibers include glass fiber and carbon fiber, and resins include ordinary unsaturated resin, vinyl ester resin, phenolic resin, and epoxy resin. Sometimes, additives are added according to the usage environment.
In the specific shape design, we consider the characteristics of the pultrusion process, avoiding asymmetric structures or complex shapes. We aim for uniform curing of the resin, ensuring a high yield rate of pultruded products. For architectural pultruded products, in addition to the above factors, we also consider dynamic loads, connection methods, and material expansion coefficients relative to other materials. When necessary, coatings can be considered for the appearance part to improve durability.

Refer to European Standard EN 13706 for more information.

Incomepultrusion Capability in Pultruded Profile

With years of experience in the pultrusion industry, incomepultrusion will help you:
Design
Choose a suitable pultruded profile for your application
Adopt a cost-effective pultruded technology
By focuing in accurate, fast, and high-tech fabrication techniques, Incompultrusion offers unlimited capability in fabricating pultruded profile. Whether you want large or small pultruded profile, Incomepultrusion has been serving the global market with high-quality fabricated profiles.
Our engineers will collaborate with your team, to meet tight tolerances and deadlines. Even for small businesses, Incomepultrusion will tailor a perfect solution for you.
Our OEM and custom pultruded profile offer diverse solutions for all our customers. Moreover, Incomepultrusion quality control begins right from choosing high-quality material, all through to testing fabricated profile quality.
What’s more, Incompultrusion offers competitive prices for all pultruded profile.  – talk to us now for the best offers.

Conclusion

In short, pultrusion is a systematic process that requires you to know your pultruded profile design, choose right pultruded profile, adopt a cost-effective fabrication technique and apply the right application.
Pultruded profile is an effective and versatile way to some application.
If you need any pultruded profile,please contact us.

Looking Forward
Your Next Project!

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