Masterbatch method masterbatching

Table 8.47 shows the available options for the analysis of polymer processing aids, namely combustion and instrumental methods. The best method is dependent on PPA type, the level to be measured, and the available equipment (see also Section 8.2.1.2). Fluoropolymer processing aid concentrations can be determined by WDXRF configured to measure either fluorine or a tracer, and by EDXRF to analyse a tracer [29]. Calibration curves are required. At present, EDXRF or benchtop XRF units cannot directly measure fluorine. For resin or masterbatch producers who prefer to make on-line XRF measurements of processing aid concentrations (to letdown levels of 50-100 ppm), processing aids that contain a tracer (usually BaS04) are available. The analysis time is less than two minutes. 

The use of the concentrate or masterbatch method has proven to be one of the most effective methods of incorporating carbon black into a resin. A masterbatch, as defined in the plastics industry, is a resin containing a high concentrate (20-50%) of pigment and other fillers that is subsequently reduced in a compound resin to accommodate the end-use requirement. 

The fabricator has several methods to choose from when blending pigments, dyes, or a masterbatch into the polymer compound. The choice must ensure that the final part meets the color needs of the end-use application. 

One method is adding color via concentrates or a masterbatch at the fabrication step (molding or extrusion). The process involves a two-component approach a natural polymer and a concentrated (solid or liquid) additive masterbatch metered and blended at the press. In this option, the fabricator must take responsibility for preblending the product, properly mixing and dispersing the two phases, and performing checks and adjustments to assure final color quality. 

Masterbatch A plastics compound which includes a high concentration of an additive or additives. Masterbatches are designed for use in appropriate quantities with the basic resin or mix so that the correct end concentration is achieved. For example, colour masterbatches for a variety of plastics are extensively used as they provide a clean and convenient method of obtaining accurate colour shades. 

Special methods of incorporation stearic acid is used to avoid sticking during the mixing red phosphorus is usually added in the form of a masterbatch containing 50 wt% red phosphorus... 

Special methods of incorporation usually surface modification of filler is performed prior to filler incorporation into the polymer high concentration of calcium carbonate (40 wt%) provides a fihn which has properties similar to paper but surpasses paper in resistance to moisture chlorinated PE containing carboxyl groups was used as compatibilizer with calcium carbonate " masterbatches of titanium dioxide contain 40-50 wt% pigment " rubber modification to incorporate zirconium silicate without a loss of mechanical strength ... 

Methods of filler pretreatment moisture removal by drying, preparation of masterbatches moisture pickup by titanium dioxide and its concentrates was found to cause lacing which causes fihn defects, drying of the filler is a simple rem-edy "... 

Accordingly, sodium hydroxide (17% aqueous solution) was stirred with the chlorohydrin ester masterbatch prepared above. The reaction was followed at 40 C using a molar ratio of sodium hydroxide to chlorohydrin ester of 2 1. The reaction was followed by gas chromatography. Fig. 18 shows the rates of conversion of epichlorohydrin and chlorohydrin ester during the reaction. Again, it was shown that after 6.5 hours all the sodium hydroxide had been consumed (cf. sodium hydroxide/sodium carbonate reaction at 40 C) at which time only 64% conversion to the epoxy compound was observed. Correspondingly the epichlorohydrin hydrolysis (25%) had increased in comparison to the sodium hydroxide/sodium carbonate method (15.6% at 40 C). 

Preparation of Elastomers. Two methods for preparing TPU elastomers are commonly used. In the prepolymer method, the polyol is prereacted with all of the MDI and the resultant prepolymer, often containing free MDI, is subsequently reacted with the chain extender. In the masterbatch method, the polyol and chain extender are premixed and then combined with the MDI,... 

A very efficient method to avoid a long induction period is to obtain an activated masterbatch of DMC catalyst. Thus, a quantity of DMC catalyst, 10-20 times higher than for normal PO polymerisation, is suspended in a purified polyether polyol used as starter (for example a polyether triol with a MW = 650-700 daltons) [51, 52]. To this suspension of DMC catalyst is added a quantity of PO, and the mixture is stirred under pressure (200-400 MPa), at 105-120 °C, until the pressure begins to decrease rapidly. A concentrated suspension of an activated DMC catalyst was obtained. By using a part of this activated masterbatch in normal PO polymerisation, the PO consumption starts immediately, without any induction period (see Figure 5.4). 

Are impact modifiers too difficult to process Impact modifiers are being supplied in easier-to-process forms. Development work with masterbatch concentrates, which are more user-friendly for the nonspedalist compounder/molder, have shown that well-dispersed talc and rubber in a masterbatch can be used to create TPOs with equivalent properties as with TPOs from traditional direct compounding. Other, "at-the-press" methods for creating TPOs or for modifying PE film are becoming possible (see Case 8.4) [7-12],... 

A surfactant-free method for the preparation of exfoliated EVA/silicate nanocomposites has been developed recently by Sogah et al. [90,91]. The process comprises two steps the first step involves the reactive solution blending of MMT-Na+ (with a CEC 0.90 mequiv. g ) with preformed random copolymers of VA and 2-(acryloyloxy)ethyltrimethyl ammonium chloride (AETMC) the second step, also made by solution blending, consists of a dilution with EVA of the masterbatch prepared in the first step. As AETMC is more reactive than... 

Shi, Y., Peterson, S., and Sogah, D. Y. 2007. Surfactant-free method for the S5mthesis of poly(vinyl acetate) masterbatch nanocomposites as a route to ethylene vinyl acetate/silicate nanocomposites. Chemistry of Materials 19 1552-1564. 

A special grade, FR-372 has been designed for PP fibre and textiles. The usual method of application is via a masterbatch containing 30-40% of flame retardant. This concentrate is then diluted in the PP to reach around 3-5% of FR-372 in the final composition. 

As LGF-PPs find their way in to new applications, it is only natural that additional performance requirements are requested by automotive molders. One such development is for exterior, unpainted panels and steps. This requires materials for these applications not only to have sufficient modulus and processability but also the abihty to withstand impact (e.g., stones and grocery carts) and maintain acceptable appearance for the life of the vehicle. Although various methods for impact modifying LGF-PPs are possible, a novel approach using masterbatches was recently reported by Richardson et al. (WO 2004/035295 Al). She... 

Fig. 17.27 Relative impact strength for PP/EPDM/Si02 and PP-g-MA/EPDM/Si02 nanocomposites as a function of Si02 content for composites prepared using hydrophilic silica and two-step processing method in which the elastomer and the filler were mixed by means of a two-roll mill at room temperature for 10 min to get masterbateh first and then the masterbatch was melt blended with pure PP. The weight ratio of PP/EPDM ot PP-g-MA/EPDM was fixed at 80/20. Data taken from Yang et al. (2006, 2007)...

Methods to prevent this diffusion gradient include preparing a masterbatch of dithiocarbamate accelerators in the polymer (HR, EPDM) and grafting accelerators onto the polymer (EPDM). One advantage of a cure system mismatch is improved ozone crack resistance. In any case, cure system location control is critical. Figure 4.10 shows the diffusion of sulfur from natural rubber to SBR. Two rubber samples are placed in contact with each other and heated. The sulfur concentration is then measured at increasing distances from the interface. In this case, considerable transfer occurs and significant concentrations build up in the SBR phase. 

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