Compression transfer moldings

CM is the most common method of molding TSs. In this process, material is compressed into the desired shape using a press containing usually a two-part closed mold and is cured with heat and pressure. This process is not generally used with TPs. TM, also called compression-transfer molding is a... 

Butler, J. A. 1964. Compression Transfer Molding, Plastics Institute Monograph, Iliffe, London. Vaill, E. W. 1962. Modern Plastics, 40, lA, Encycl. Issue, 767. 

RTM was described May 1957 (at the BPF Reinforced Plastics Conference), in a paper on work dating from 1954 at Bristol Aircraft, Filton, UK. It is basically a liquid resin version of compression transfer molding a process in which a charge of compound is placed in a transfer pot and is injected into a closed mold, usually by a plunger system. The method allows the compound to be suitably prepared melt and then transferred fast and accurately into the mold, in which the required reinforcement has already been placed, in suitable form. 

Amino molding compounds can be compression, injection, or transfer molded. Urea molding compound has found wide use and acceptance in the electrical surface wiring device industry. Typical appHcations are circuit breakers, switches, wall plates, and duplex outlets. Urea is also used in closures, stove hardware, buttons, and small housings. Melamine molding compound is used primarily in dinnerware appHcations for both domestic and institutional use. It is also used in electrical wiring devices, ashtrays, buttons, and housings. 

Nittile mbber is much like SBR in its physical properties. It can be compounded for physical strength and abrasion resistance using traditional fillers such as carbon black, siUca, and reinforcing clays. The primary benefit of the polymer is its oil and solvent resistance. At a medium ACN content of 34% the swell in IRM 903 oil at 70°C is typically 25—30%. Nitrile mbber processes on conventional mbber equipment and can be compression, transfer, or injection molded. It can also be extmded easily. 

Urethanes are processed as mbber-like elastomers, cast systems, or thermoplastic elastomers. The elastomer form is mixed and processed on conventional mbber mills and internal mixers, and can be compression, transfer, or injection molded. The Hquid prepolymers are cast using automatic metered casting machines, and the thermoplastic peUets are processed like aU thermoplastic materials on traditional plastic equipment. The unique property of the urethanes is ultrahigh abrasion resistance in moderately high Shore A (75—95) durometers. In addition, tear, tensUe, and resistance to many oUs is very high. The main deficiencies of the urethanes are their resistance to heat over 100°C and that shear and sliding abrasion tend to make the polymers soft and gummy. 

Polyvinyl Chloride (PVC) 1940 M-H VG G G G Extrusion, injection, rotational, slush, transfer, compression, blow mold Pipe conduit and fittings, cable insulation, downspouts, bottles, film... 

Diallyl Phthalate (DAP, DAIP) Powder Excellent humidity resistance. Withstands temperatures over 400 F. Easily processed. Dimensional stability excellent. May be compression, transfer and injection molded. Low cost. Precision potentiometers, RF connectors, waveguide auxiliaries, attenuators, heating panels, heated battery cases. 

Phenolics Elastomers Powder, solutions Excellent thermal stability to over 300 F generally, and over 400 F in special formulations. Broad choice of resins. May be cast or compression, transfer, or injection molded. Precision potentiometers, RF connectors, heating panels. 

Injection Molding Extrusion Blow Molding Thermoforming Reaction Injection Molding Rotational Molding Compression and Transfer Molding Matched Mold Spray-up... 

Thermosets are processed by compression molding, transfer molding and injection molding or by extrusion, depending on their structure. The pressing temperatures are about 150 to 190°C. Corresponding requirements are placed on the pigments. Dyes are often also used to color thermosets. 

Molding employs a mobile prepolymer that may be thermoset or using a thermoplastic polymer. The polymer can be injection-molded (often for solid objects), blow-molded (for hollow objects such as bottles), rotation-molded, compression-molded, transfer-molded, or thermoformed. Casting is closely related to molding, except that the pressure is typically not used. 

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