E7 is coming!
With the advancement of technology, the scope of application of fiberglass is ever expanding. People are more and more demanding on the performance of fiberglass. As a reinforcing material, it has always been a priority to increase the mechanical properties of fiberglass. Especially in recent years, due to worsening energy crisis and deteriorating ecological environment, people pay more and more attention to power generation with large wind blades and light-weighting of automobiles.
At this point, high strength high modulus fiberglass composites naturally become the focus and priority for research and development in the industry due to their excellent mechanical properties, a relatively low specific weight and appropriate production cost. Jushi Group E7 glass fiber was created right in this background.
Successful Development of E7
According to Dr. Zhang Zhijian, director of Jushi Product R&D Center, E7 high modulus high strength glass fiber represents the high-end products of Jushi Group. The outstanding performance it demonstrates in the process of volume production makes it possible to meet the large demand of high performance fiberglass from large wind blades, pressure vessels and pultrusion sectors .
According to Mr. Zhang Lin， glass engineer of Jushi Glass Research Center, the success development of E7 glass fiber has a very important meaning for the promotion and development of high performance composites, which is mainly manifested in the following three aspects:
Firstly, E7 has high cost performance. Although S-glass fiber is well known, its high manufacturing cost is more than what the majority of the composites sectors can bear. The volume production of E7 with large-scale furnaces and the excellent cost control capability of Jushi Group make E7 even more competitive.
Secondly, it is highly environment friendly. E7 is also boron-free and fluorine-free. To make the glass, a number of advanced melting technologies are used such as oxygen firing technology to reduce waste gas emissions by 80% and nitrogen oxides emissions by more than 90%, environmentally friendly tank furnace technology to achieve zero waste fiber discharge and wastewater recycling technology to achieve zero discharge of industrial wastewater.
Thirdly, E7 is a high strength high modulus glass fiber. Compared with traditional E-glass fiber, E7 glass fiber-based composites have even more superior mechanical properties: about 23% increase in its elastic modulus, about 30% increases in tensile strength and a softening temperature about 80℃ higher than traditional E-glass fiber. E7 can make composites products more durable and its excellent properties, especially mechanical properties, allow customers to design high performance products which exceed the limits of traditional materials.
However, Zhang Lin added that the development process of E7 was not easy. "From the beginning of 2009, the Group began to invest heavily in research and development of a new-generation fiberglass. At the beginning, other domestic manufacturers have not yet begun such development, so there was no experience to draw on. We can say we are 'the first person to eat crab’. We had a very clear objective then which was to significantly improve the various properties of our E6 glass fiber, ” Zhang Lin said. During the development, several comprehensive tests were conducted on a large-scale furnace. “Currently, we have been able to carry out the stable volume production of E7. "
Ms. Zhang Yan, deputy chief engineer of Jushi Group R&D center, mentioned that E7 is outstanding in high-strength and high modulus and therefore especially suitable for the development and manufacture of large megawatt wind blades and pressure vessels.
Broad Downstream Market
It took Jushi Group five years to successfully develop E7 glass fiber and Jushi Group has completely independent intellectual property rights over E7. Its chemical composition falls outside the scope of the traditional E-glass according to ASTM D578-00 and complies with R-Glass fiber classification according to ISO 2078 standards. It is a leading product among similar products of the world fiberglass industry.
Zhang Yan emphasized that E7 has all existing excellent properties of E-glass fiber and at the same time technological breakthroughs are made in its modulus, strength, softening temperature and other properties. It can meet the special needs of high-end products. E7 is a new technology platform of Jushi Group, a series of products that are developed based on this platform are suitable for a wide range of applications. E7 is a brand new solution to address the various needs of different customers.
As a new-generation high-performance glass fiber, upon being launched, E7 has received a lot of attention. For example, Hengshi Fiberglass Fabrics Co., Ltd， a major customer of Jushi Group, are working on obtaining qualifications for its products developed using E7 roving for use in wind blades. The qualifications are progressing well and many domestic and foreign well-known customers have given very positive feedback. Mr. Zhou Xiaohua, manager of Hengshi Product R & D, said that the excellent mechanical properties and high cost performance of E7 are the most important reasons why Hengshi and downstream customers are very interested in using the material.
Take for example the unidirectional fabric UD1200 produced by Hengshi and widely used in the wind blades. Compared to boron-free E-glass-based product 398, E7-based product 380 has an about 30% increase in tensile strength, about 11% increase in modulus and significant increase in shear and compression properties. In terms of fatigue resistance, laminates prepared using E7-based 380 have over 15% increase in fatigue life over laminates using the boron-free E-glass-based product 398 under the same load ( by calculating the log of the number of cycles).
Take for another example the new-generation high performance roving 312T for pultrusion. Compared to the boron-free E-glass-based product 312T, the E7-based product 312T has an about 15% increase in tensile strength and about 10% increase in tensile modulus.
E7DR-380 is an alkali-free glass direct roving and based on high modulus high strength E7 glass formulation. It is treated with a silane-based sizing specifically designed for epoxy resin and suitable for amine or anhydride curing systems. E7DR-380 is specifically designed for the weaving processes to make woven rovings and multi-axial fabrics which have high requirements in mechanical and fatigue properties. It can also be used in the winding process for high-pressure applications. Its typical applications include wind blades, prepregs, high-pressure pipes and vessels. It is characterized by fast wet-out and wet-through, good abrasion resistance and smooth transfer between roving packages; suitability for weaving and stitching processes; excellent mechanical properties and fatigue resistance; higher strength and modulus.
According to Zhou Xiaohua, when taking E7DR-380 for example, firstly, the product can reduce the weight of wind blades so that the wind blades can perform well on the land where the wind speed is low or medium. Furthermore, according to the theoretical calculations, wind blades using E7DR-380 have a life time more than 15% longer than that of wind blades using traditional E-glass fiber. Finally, high modulus high strength E7DR-380 offers unlimited opportunity for manufacturing large megawatt wind blades.