Powder slush

Other material systems are finding increased usage. A blend of SMA and HIPS is used in automotive dashboard parts. PVC/ABS blends are used for powder slush molding of IP skins. 

Rotoflex, Powder slush molding compound, CONDEA Vista Co. 

Injection is by far the most used moulding process but compression and compression-transfer are used for specific cases. Rotomoulding is specifically used for polyethylene and a few other powdered resins. Slush moulding is broadly used for automotive dashboards. Generally ... 

Slush moulding used with thermoplastics in powder form for the fabrication of automotive dashboards ... 

Slush moulding is also suitable for other polymer powders such as TPU or for polymer liquids. 

C. Dry Ice Baths. In contrast to the fixed temperature of slush baths, a Dry Ice bath is somewhat less reliable because the equilibrium temperature is a strong function of the partial pressure of C02 above the bath. For example, one test in which Dry Ice was freshly powdered in air had a temperature 8°C below the normal sublimation temperature of —78.5°C. In another test, 40-h standing was required for a Dewar of Dry Ice to attain —78.5°C.1 However, a small electric heater buried in the Dry Ice produced enough C02 to expel the air and attain the normal sublimation temperature in a matter of minutes. The temperature of an equilibrated Dry Ice bath at any barometric pressure may be found using the expression for sublimation pressure ... 

They can be processed by techniques commonly used for thermoplastics, such as extrusion, injection molding, rotational molding, dip, slush molding, and powder and fluidized bed coating,16 and can be expanded into foams.17 Compression and transfer molding of FEP resins can be done, but with some difficulty. Extrusion of PEP is used for primary insulation or cable jackets and for tubing and films. 

Solid Na[Zn2(CH3)2H3] can be isolated in high yield by cooling the solution in a Dry Ice bath for several days, whereupon large, colorless, needle-like crystals form. These may be filtered off at — 78° using the apparatus shown in Fig. 3. After the crystals are washed with several 10-mL portions of cold, dry THF, they are held under vacuum at —22° (carbon tetrachloride slush bath)7 for several hours to remove excess THF. Under these conditions, the crystals lose solvent to form a white powder, which unlike the parent crystals does not melt upon warming to room temperature. Anal. Found Na/Zn/CH3/H, 1.01 1.98 1.98 3.01. In addition, 2.3 mol of THF was retained per mole of Na[Zn2(CH3)2H3] for this sample however, the exact value varies from one preparation to another. No iodide was detected in the product. 

Freshly prepared lithium wire, and selenium and tellurium powders were used as supplied. Germyl fluoride may be prepared from germyl iodide11 and lead(II) fluoride.12 Chlorotrimethylsilane is distilled through traps at -45° (chlorobenzene-liquid N2 slush), -78° (methanol-dry ice slush), and -196° (liquid N2) the fraction retained in the trap at -78° is the desired purified chlorotrimethylsilane. Peroxide-free diethyl ether was distilled in a vacuum system from fresh Li[AlH4] and stored in vacuo. Caution. The use of Li[AlHA] for drying ethers can lead to explosions 3 Commercial dry NH3 (10-15 mL portion) was further dried by condensation onto Na pellets (about 1 g) in an ampul (about 50 mL) held at -78° on the vacuum line. After 30 minutes the dried NH3 was pumped from the ampul and degassed in a trap held at -196° before use. 

A 2.0-g. sample of powdered dicobalt octacarbonyl is placed in a 25-ml. glass reactor in a nitrogen-filled glove bag. The reactor is evacuated then 5 g. of trichlorosilane is condensed from the vacuum system into the reactor which has been cooled to —196°. The Teflon stopcock is closed, the reaction vessel allowed to warm to room temperature, and then the reactants are permitted to stand for 24 hours. Cool the reactor to —42° (diethyl ketone slush), open the Teflon stopcock, and remove the excess silane and noncondensable substances into the vacuum system with pumping. The remaining dry, solid material is then transferred in a nitrogen (or carbon monoxide) filled glove bag to a sublimation apparatus. The solid is then sublimed in vacuo... 

Slush powders were prepared from mass polymerised and suspension polymerised vinyl chloride polymers and the absorption of plasticisers into the polymers was investigated using the Haake rheomix procedure. The fusion behaviour of the powders was also investigated and the morphology of the particles analysed by scanning electron microscopy. The properties of the two different powders are compared. 6 refs. 

In a 2-L round-bottomed flask equipped with a magnetic stirrer, 433 g (2 moles) of red HgO [Alfa] is dissolved in 320 mL of trifluoroacetic acid [PCR]. Enough water ( 50 mL) is added to prevent crystallization of the white Hg(Cp3COO)2. Excess acid and water are removed by means of a rotary evaporator. The solid residue is finely powdered in a dry atmosphere (glove bag), dried under vacuum (10 torr) at 120°, carefully mixed with 500 g of K2CO3 (dried at 200° under vacuum), and placed in a 120 x 7-cm i.d. glass tube equipped with a 100-mm flange at the open end (Fig. 1). The reaction tube is attached to an oil pump via a by-passed silicon-oil bubbler and a COa/acetone slush bath. The pressure in the system may be adjusted by means of a leak valve that is open to the air. The reaction mixture is heated to 100° at 10 torr (open by-pass) for another... 

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