Two-component mold

The unique attributes of "catalyzed resins are that they eliminate the need for secondary (after molding) pre-plate activation or "seeding" operations common to conventional plating-on-plastics (POP) processes. For molded circuit board manufacture, catalytic resins are used in two-shot (two-component) molding processes which form highly complex 3D plastic structures which are capable of being selectively plated without the need for plating masks or resists. Polymers currently available in a "catalytic" composition include only amorphous sulfone and imide based systems. 

FIGURE 1.71 Two-component mold for toothbrushes with preform carriers in chain design and two additional functional stations [38]... 

Sanitary ware, including tubs, showers, combined units, basins, and toilet tank, may be made of thermoformed ABS or acryHc sheet, molded glass-fiber-reinforced polyester, or cast acryHc resins. The glass-polyester type dominates the tub/shower market. It is possible to install the units as a two-component system, assembled in place. Gel coats may be of thermoformed decorative acryHc skins. To reduce the smoke generated by fire, methyl... 

Two-component urethane adhesives are used to bond sheet molding compound (SMC) panels for automotive OEM and aftermarket applications. Two-part urethanes are used as laminating adhesives in the RV industry. 

In general, their are two components, a screw and a cylinder/ram assembled in a 90° V configuration. The rubber is fed into the screw, which forces the rubber into the cylinder. When the cylinder is full, the ram then forces the rubber into the runner system and the mold. 

The TLCP used was a widely investigated one, Vectra A950, manufactured by Hoechst-Celanese. The PC was produced by Enichem under the tradename Sinvet 303. Table 3 lists the main properties of these materials according to the manufacturers. The materials were dried in a vacuum oven at 120°C for 4 h before processing. Prior to injection molding of the composite samples, two components were melt mixed by a ZSK, W P, Stuttgart, extruder with a constant weight ratio of PC-TLCP = 80 20 [23]. 

Otto Bayer produced PUs in the 1940 s by reacting diisocyanates, such as tolyl diisocyanate, with dihydric alcohols, such as ethylene glycol. In another experiment he added a diisocyanate to cure synthetic rubber (SR) containing hydroxyl groups. The rubber was cured (vulcanized), but it stuck to the mold. Variations of products from these two experiments are now used as two-component adhesives for bonding footwear and automotive plastic parts. 

Two-component systems are used for reactive processing the first component may be an unsaturated polyester, containing an initiator and 30% monomer the second may be the same mixture but with the addition of copolymerization accelerators. The polymerization rate is increased if heated molds are used. 

Figure 1. Liquid injection molding for a two component system...

The assimilatory enzyme from the mold Neurospora crassa has been intensively studied for over two decades, particularly by Nason and his collaborators. Thus, Nason and Evans (39) identified FAD as a prosthetic group in the enzyme Nicholas, Nason, and McElroy (40) showed that molybdenum was required for the synthesis of nitrate reductase Nicholas and Nason (41) suggested its presence in the enzyme Garrett and Nason (42) showed that a b-type cytochrome (cytochrome 6557) co-purifies with this nitrate reductase and Nason et al. (11) suggested, from in vitro complementation experiments with nitrate reductaseless mutants, that the enzyme consists of at least two components required for activity. These workers have suggested that the electron transfer pathway is ... 

Two-component injection machines, using separate injection units for each of the two components perform the standard sandwich molding process. This process is characterized by a sequential injection of the two components using the same gating system. After filling the mold partially with the skin material with one injection unit the core component will be injected by the second injection unit. In order to avoid flow marks on the part surface a simultaneous phase is inserted between the injection of skin and core components. The final packing phase may be performed either with the core or the skin component. 

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. 

Opportunity. A three-color concentrate-two-component plastic colorants A, B, and C and components D and E are mixed, then injection molded to form a dimensional product.The customer is pleased with dimensional characteristics but has noted some increased color variance to a more positive DH value in recent lots. While none of the lots has exceed the 0.4 maximum specification, all of the most recent shipment was at or near that tolerance. 

The first device integrated a microstructured multichannel plate fabricated by micro-injection molding from a two-component liquid silicon rubber material (Silopren LSR 4070) with an appropriately interfaced and temperature-controlled housing, as shown in Figure 3.1a. 

Reaction injection molding (RIM) is a process where a controlled chemical reaction occurs in a mold after injection of the material components. Commercially, the process is used almost exclusively for production of polyurethane parts by injecting a two-component system of isocyanate and alcohol (Figure 14-54). Polyurethanes can be produced with a wide range of properties, from very low density foams to reinforced, structural components. RIM is widely used... 

One component contained the isocyanate and epoxy resin, and the other component contained the polyols, chain extenders, catalysts, fillers, and plasticizers. The two components were then mixed together for 30 seconds (at room temperature) using a high speed mechanical stirrer at 2000 rpm. The mixture was then quickly poured into a pre-heated mold and pressed on a laboratory platen press at 100 C. The sample was removed from the press and demolded 30 minutes after it gelled. The gel time was approximately 3-6 minutes. The post curing condition was for 5 hours at 120 0. 

These are silicones in liquid or paste form that can be transformed into cross-linked elastomers at or near room temperature. There are two basic types, one component and two component. The one-component room temperature vulcanizing (RTV) elastomers cure upon exposure to air. A typical material of this type is synthesized from a dihydroxy-terminated siloxane oligomer and methyltriacetoxysilane (Scheme 2). The resulting tetraacetoxy compound will flow as a paste and so can be molded into shape. Hydrolysis of the acetoxy groups takes place over a period of hours. Condensation of the resulting silanols gives a highly cross-linked end product. 

Room temperature hardenable vulcanizable two-component silicone rubbers are usually formulated as flowable materials. They contain reinforcing and extending fillers. Their flowability means that they are able to flow into the finest details of the to be reproduced item. After vulcanization a negative mold is produced, which is complete reproduction of the original in all its detail. This technology is utilized for the restoring and duplication of... 

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