LFI-PUR, a breakthrough in the injection of parts of PU reinforced with glass fibers

It strengthens the castings of PU's long dimensions

It is not often hear talk of completely new technologies in the field of the transformation of polyurethane. However, Krauss Maffei has launched the technique PUR-LFI (long fibres of glass-PUR injection) for the economic production of molded parts of polyurethane reinforced glass fibres, which very soon could be in the market.

The fundamental innovation of the LFI-PUR, patented process, is that the fibers of glass from 12 to 100 mm in length are dipped by the system a processor specially developed for this application head polyurethane, and are introduced at the same stage of work in the cavity of the mould. Fiberglass withdraws from the roving and thread and a cutter the short directly on the processor head to the desired length. With the head processor LFI, the part of the glass fibres can be regulated continuously during the introduction of the mixture, with which different parts of the molded parts are molded according to the load to resist.

The main advantages of the LFI-PUR method are:

-the reduction of costs through cost effective transformation of rovings - no preconditioning of mates of glass - the distribution of glass fibers regarding the burden to resist - the very good mechanical resistance along with very low densities - suitable for the manufacture of high stability light pieces.

After the draft, the castings have almost no deformations some and are characterised by very good stability on temperature, as well as very thin walls easily achievable with the already wet glass fibers.

The LFI-PUR process is also appropriate for the scenery for foamed sheets and decoration fabrics. Lists parts of construction for the most part are can be manufactured in a single phase of work to be installed.

The consequent further development of the LFI-PUR technology is innovation PUR-NFI of Krauss-Maffei which corresponds to the LFI concept, but that transforms natural fibers instead of glass fibres, and thereby rovings renewable raw materials.

Natural fibres are more profitable than glass fibers. With an average density of the castings of approx 0, 55kk/dm ³ are ideal for lightweight construction. Application of recipes with actors internal unmoulders makes it possible to renounce paint the surface of the castings of agents unmoulders. During the latest recycling by thermal recovery not occur glass waste some; the natural circuit CO₂ is not loaded because only releases the CO₂ before linked by the plant.

First of all, these technologies are suited for the manufacture of internal parts in automotive: coverings of doors, panels of instruments, hangers, etc.

In combination with a leaf vacuum-moulded, NFI-PUR could also be of future interest to the industry of furniture and construction.

The combination of known procedures

The combination of the preparation of compounds with the injection moulding leads to the inyección-preparación line. The preparation of compounds of plastics filled or reinforced directly during the process of molding by injection offers two advantages to the transformer of the plastic: it can reduce the cost of equipment and gains in flexibility.

The necessary transition of the continuous preparation to the intermittent injection moulding is achieved with the Compounder. Viewed from the side of the construction of machines, alternating injection molding process is done through two groups of injection by piston which are activated and filled mass by a tour of the Compounder of continuous functioning valve.

The wide variety of examples of the application shows that the more high-performance production is only achieved with global systems. Currently, classic application technology is in the State of renewal which is reflected in the high-speed innovative technique of facilities and equipment.