LANXESS is expanding the application range of extrusion blow molding. Now, TePEx brand continuous fiber reinforced thermoplastic composite materials can also be used in blow molding processing.
In a feasibility study, LANXESS proved that parts made of polyamide 6 can be produced by blow molding and can also be partially reinforced with Tepex composites on the bearing points. The research was carried out by the LANXESS High Performance Materials business unit in Dormagen, Germany, on an advanced blow molding machine in its technology center.
Arthur Rieb, an expert in the High Performance Materials business unit of LANXESS, explains: “These components exhibit excellent adhesion, which makes it possible to take advantage of the strong strength and rigidity of Tepex.”
This process can be used to locally improve the mechanical properties of blow molded parts, such as areas subject to high mechanical stress due to impact load or high pressure. Rieb explained: “In addition, this technology is also suitable for the production of blow-molded structural parts, such as hollow profiles for body reinforcement. Widespread use of Tepex is a key factor in reducing weight and material consumption, because it can reduce the basic Wall thickness."
Based on a complete thermoplastic system, this hollow part is easy to recycle, which makes it easier to establish a closed-loop material cycle.
The blow molding step determines the cycle time
In the production of this hollow part, the tubular parison is first extruded, and at the same time, the heated and plasticized Tepex insert is placed in the blow mold. Next, the parison is inflated in the mold, and the Tepex part is shaped accordingly. In this way, a part with a designed shape and partially reinforced by Tepex is obtained.
Riebs added: “Because Tepex molding is integrated into the blow molding process, the end result is that the entire process only requires a short step, which is a typical blow molding process with short cycle times and high economic benefits.
Simplified process
Previously, the production of such parts involved subsequent welding of two- or three-dimensional Tepex inserts to blow-molded hollow parts. For the two-dimensional situation, the completion of the entire process is divided into two stages; for the three-dimensional situation, the completion of the entire process is divided into three stages, and Tepex needs to be preformed.
Tilmann Sontag, a lightweight design expert at the Tepex Automotive Group, a business unit of LANXESS`s high-performance materials, said: "Therefore, our process makes things easier. In addition, the textile reinforcement makes the plasticized Tepex material better than the continuous fiber unidirectional reinforcement. The strip is easier to handle, which makes the production process stable and safe."
Fully consolidated material bonding
The continuous fibers in Tepex are fully pre-impregnated with the resin, so the pressure during the blow molding process is sufficient to cure the material so that no air pockets are formed.
Sontag said: "As a result, an excellent material bonding force is formed between the blow molding material and Tepex. Even at low blow molding pressure, it is sufficient to mold Tepex into a key three-dimensional shape."
Wide range of blow-moldable polyamides
LANXESS`s high-performance materials business unit has developed a wide range of high-viscosity compounds based on polyamide 6 and polyamide 66 with and without glass fiber reinforcement. These materials can also be used in new processes or material combinations. For example, these materials include very soft, impact-resistant products, unreinforced polyamide 6 compounds Durethan BC700HTS DUSXBL and Durethan BC550Z DUSXBL. This type of material is very suitable for containers reinforced with Tepex or other hollow parts that also require high impact resistance and flexibility. On the contrary, the glass fiber reinforced product type is the material of choice for lightweight structural components.
Tepex can also be used in this process with many other products, such as continuous fiber fabric reinforcements, or laminates made of glass fiber, aramid fiber or carbon fiber. The matrix of the composite material can also be changed. For example, in addition to polyamide 6 or polyamide 66, it can also include polyolefins, such as polypropylene or polyethylene.