Multi-component injection

The use of the hot runner technology allows only certain component geometries and mold concepts. With hot runner systems, gating positions are achieved that cannot be reached conventionally the active movement or complete avoidance of fill lines can be implemented by sequential injection multi-component injection molding can be performed with up to five materials in a mold high-speed stack molds can be built film and fabric can be back injected gas and water injection technology can be implemented multi-cavity molds can be realized clean room production can be optimized and the co-injection technique can be enabled. 

In the past few years, we have seen trends where more complex manufacturing systems are developed that manufacture parts using various materials and components such as coextrusion of multilayer films and sheets, multi-component injection molding, sandwiched parts or hollow products. 

In contrast to multi-color and multi-component injection molding, co-injection molding uses the same gate and runner system. Here, the component that forms the outer skin of the part is injected first, followed by the core component. The core component displaces the first and a combination of the no-slip condition between polymer and mold and the freezing of the melt creates a sandwiched structure as depicted in Fig. 3.51. 

Sinton, D., Ren, L.Q., Xuan, X.C., Li, D.Q., Effects of liquid conductivity differences on multi-component sample injection, pumping and stacking in microfluidic chips. Labchip 2003, 3, 173-179. 

The granulator with coupled reactive absorption is modeled in such a way that simultaneous computation of the conversion of the component removed from gas and granulates growth is considered. A balance area from the bottom to the top of the fluidized bed, including the apparatus wall, has been considered. The gas fluidizes particles above the air distribution plate, whilst liquid injection is possible from all directions by using either one-component or multi-component nozzles in the... 

Use analytical injection of a typical feed or a multi-component standard having the components of the feed to screen the most appropriate mechanism. This is done by selecting media and mobile-phase systems, measuring the separation factor of the product and neighboring impurities. The determination of a preliminary regeneration scheme may be required to improve the time to perfonn the screening experiments. 

This worked example is a very good demonstration of how efficiently the autoprep systems can separate multi-component mixtures into pure fractions. As previously mentioned, the results shown were from pilot autoprep injections which were run with a very low collection threshold. With subsequent, more informed setting of the collection threshold the degree of contamination of some of the fractions from the main peak could be further reduced leading to a high degree of purity for all fractions collected from the main peak. 

The additive standards for the MS library were dissolved in a suitable solvent and a sample was injected into the GC/MS system, or a sample was transferred into an injection port liner as is done for real world samples. Additive standards were mn at temperature program rates of 10 °C or 15 °C due to the lack of the necessity for multi-component separation. The actual temperature program used is listed on each Total Ion Chromatogram (TIC). 

The purpose of this paper was twofold (i) to investigate how to visualize all four perturbation peaks on a quaternary concentration plateau and to (ii) validate the accuracy of the PP method for determination of isotherm parameters directly from quaternary mixtures of l/l/l/l compositions. For this purpose the technique developed and validated for the binary case in papers IV and V (the Lindholm-technique ) was extended to the multi-component case. The approach is to inject the same excess as deficiency for every second solute. Thus, in a quaternary system the excess of components 1 and 3 is the same as the deficiency of components 2 and 4, or the converse. The concentrations of the components in the sample can be calculated according to Csample i = Chateau i - (-1 ) n, for some number n chosen so that the injected concentrations always are equal to or greater than zero. This technique made all perturbation peaks clearly detectable, although the area were not the same for all of them, see Figure 22. 

Figure 23. Comparison between single- and multi-component elution profiles (dotted lines) with calculated ones (solid lines). The sample injected was 60 gL 1.250 mM of (a) component 1, (b) component 1-2, (c) component 1-3 and (d) component 1-4.

Formulations for producing polyurethanes (PUs) by reaction injection moulding (RIM) usually contain mixtures of polyols and diols in order to achieve the desired properties in the moulded part. The present work forms part (1) of a systematic investigation into the effects of polyol blends and glass fibres on the physical properties of unfilled and filled PUs formed by RIM. In the case of unfilled PUs, by using a multi-component polyol mixture, it is possible to investigate the effects on properties of (a) polyol structure, molar mass and functionality, (b) the relative proportions of diol-based hard blocks and triol-based soft blocks and (c) polyol blend compatibility. The... 

If mixtures of solutes are injected into a chromatographic system, not only interferences between the amount of each component and the adsorbent but also between the molecules of different solutes occur. The resulting displacement effects cannot be appropriately described with independent single-component isotherms. Therefore, an extension of single-component isotherms that also takes into account the interference is necessary. For the modified Langmuir isotherm the extension term is shown in Eq. 2.43, representing the multi-component Langmuir isotherm. 

An extension to multi-component systems is straightforward, by injecting more than one component. A prerequisite is the measurement of the concentration profile of each solute during the elution. This can be achieved either by using solute-specific detectors or by collection of multiple fractions and subsequent chemical analysis... 

M. Blanco, J. Coelho, H. Iturriaga, S. Maspoch, M. Redon, J. Riba, Multi-component analysis of concentrated solutions by flow-injection analysis with zone sampling and partial least-squares resolution, Anal. Chim. Acta 259 (1992) 219. 

Evaporation of drops of multi-component solution into an inert gas, plays an important role in such processes as dehydration and humidifying of gas by the method of jet spraying, combustion of liquid fuel injected into the combustion chamber of engines and heating systems, etc. 

G. S. Zhu, R. D. Reitz, J. Xin, and T. Takabayashi. Characteristics of vaporizing continuous multi-component fuel sprays in a port fuel injection gasoline engine. SAE Paper 2001-01-1231,2001. 

Mikell Knights, K 2004 Wrap-Up Injection Molding. Spotlight on Electric and Multi-Component Machines, Plastics Technology Magazine, vol. 51, no. 1, pp. 38-45, 2005. 

Alternatives to multi-component injection moulding are worth considering too. These techniques have not yet been referred to in the present chapter. 

HR technology may he employed for special injection methods, like in-monld, i.e., lamination of inserts made of film and textile liners, injection of foam plastics, multi-component injection, inert-gas-assisted injection, etc. 

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