Development history of fiberglass pultrusion process

FRP Pultrusion Machine Manufacturers

Since its inception in the United States in the 1950s, the production process of pultruded fiberglass reinforced plastic profiles (GFRP) has been in a slow development process due to limitations in the craftsmanship of raw materials. By the end of the 1970s, the successful development of raw materials such as synthetic resin, glass fiber and fabric suitable for the application of pultrusion process led to the rapid development of pultruded GFRP technology. In the 1980s, the annual growth rate of pultruded GFRP products in the United States was 12.5%. In the early 1990s, my country introduced foreign production lines. The main advantages of pultruded GFRP profiles are lightweight, high strength, corrosion resistance, electrical insulation, strong designability, and good strength and elasticity, allowing people to have greater freedom in the design of structural shapes and material properties. Due to its low elastic modulus and strong anisotropy, the main drawback of GFRP is the difficulty in designing its connection and load-bearing structures. At present, the application of pultruded GFRP profiles as load-bearing structural members has become increasingly mature at home and abroad, such as offshore drilling platforms, chemical plant operating platforms, factory beams, skylights and bridges, street overpasses, etc., among which there are many application examples. The design method of pultruded GFRP structures basically adopts “equivalent design”, that is, GFRP materials are used to replace other materials (for anti-corrosion or other advantages) while the structural shape, load, and use environment remain unchanged. The design method adopted follows the design method of the raw materials, while taking into account the characteristics of the pultruded GFRP profiles, and sometimes even only replaces them with the same strength and stiffness. GFRP stretch extruded profiles have high tensile strength and are superior to other strengths. The specific strength of GFRP profiles pultruded with 25% resin can reach 36km, which is twice the 17km of aluminum alloy materials and more than 50% greater than the 23km of high-strength steel wire. Most of GFRP pultruded profiles can be used structurally as rods or beams, so the design should be based on this. This assumption, in addition to following the general basic assumptions of composite material mechanics, takes into account the inhomogeneity of the material over the profile cross-section and takes isotropic faces into account. Anisotropy exists only in the longitude and latitude directions.

Since its inception in the United States in the 1950s, the production process of pultruded fiberglass reinforced plastic profiles (GFRP) has been in a slow development process due to limitations in the craftsmanship of raw materials. By the end of the 1970s, the successful development of raw materials such as synthetic resin, glass fiber and fabric suitable for the application of pultrusion process led to the rapid development of pultruded GFRP technology. In the 1980s, the annual growth rate of pultruded GFRP products in the United States was 12.5%. In the early 1990s, my country introduced foreign production lines. The main advantages of pultruded GFRP profiles are lightweight, high strength, corrosion resistance, electrical insulation, strong designability, and good strength and elasticity, allowing people to have greater freedom in the design of structural shapes and material properties. Due to its low elastic modulus and strong anisotropy, the main drawback of GFRP is the difficulty in designing its connection and load-bearing structures. At present, the application of pultruded GFRP profiles as load-bearing structural members has become increasingly mature at home and abroad, such as offshore drilling platforms, chemical plant operating platforms, factory beams, skylights and bridges, street overpasses, etc., among which there are many application examples. The design method of pultruded GFRP structures basically adopts “equivalent design”, that is, GFRP materials are used to replace other materials (for anti-corrosion or other advantages) while the structural shape, load, and use environment remain unchanged. The design method adopted follows the design method of the raw materials, while taking into account the characteristics of the pultruded GFRP profiles, and sometimes even only replaces them with the same strength and stiffness. GFRP stretch extruded profiles have high tensile strength and are superior to other strengths. The specific strength of GFRP profiles pultruded with 25% resin can reach 36km, which is twice the 17km of aluminum alloy materials and more than 50% greater than the 23km of high-strength steel wire. Most of GFRP pultruded profiles can be used structurally as rods or beams, so the design should be based on this. This assumption, in addition to following the general basic assumptions of composite material mechanics, takes into account the inhomogeneity of the material over the profile cross-section and takes isotropic faces into account. Anisotropy exists only in the longitude and latitude directions.

The pultrusion process was studied as early as 1948. It was first registered and patented in the United States in 1951. It was only in the early 1970s that it truly entered the field of structural materials. After that, the pultrusion process became a widely used process technology and gradually attracted the attention of all sectors of society. With the improvement of raw materials and equipment manufacturing levels, many key technologies of the pultrusion process have made major breakthroughs and achieved rapid development.