Back-foaming mold

As with the so-called slush process, slush skins, which are manufactured in the spray or casting method, are inserted into a back-foaming mold in a second work step and are back-foamed there with a PU foam and connected with a carrier. When the part geometry allows, an effort should be made to design the mold to allow to spray and then back-foam or back-inject in the same mold. 

In this case the designer has freedom of choice of both form and dimension as well as in the selection of the materials. Given this freedom, it would be desirable to examine several of the alternatives to see which would provide the best seating at the lowest cost. Obviously, there is no point in doing all of the possibilities so a selection should be made on the basis of anticipated use as well as style requirements. Three types will be analyzed. They are the single curve sheet cantilever mounted from the back, the molded pan supported on four legs, and the structural foam molding which is front supported. 

Molded flexible foam products are becoming more popular. The bulk of the molded flexible urethane foam is employed in the transportation industry, where it is highly suitable for die manufacture of seat cushions, back cushions, and bucket-seat padding. TDl prepolymers were used in flexible foam molding in conjunction with polyether polyols. The need for heat curing has been eliminated by the development of cold-molded or high resiliency foams. 

Within the limits set above the design can vary widely. The seat can be attached to the rest of the chair frame by leg supports at the four corners, or it can be cantilevered from the back with a floor pad support, or, in another version, from the front (Fig. 14-6). The seat construction can range from a formed sheet in two or three dimensions to one with rolled edges for reinforcement. It can have structural ribs molded in or it can be a sandwich panel construction made up of two molded parts cemented together. If can also be a structural foam molding, which is a sandwich panel construction. In each of the configurations there are tradeoffs of stiffness and strength which... 

The other type of venting is the back foaming of inserted foils or rigid Inserts in one or both mold halves. Examples are top-quality interior trim for vehicles, instrument panels, glove boxes, and door panels. A soft skin or foil is inserted into the lower... 

An example of the contribution of polar interactions between an acrylic PSA and a substrate is shown in Fig. 6. By copolymerizing iso-octylacrylate and acrylic acid, using a monomer ratio of, respectively, 95/5 and 90/10, two otherwise identical PSAs were made. The PSAs were laminated to both sides of a foam core to make an attachment tape as used in the automotive industry for the application of body side moldings to a car. One side of the foam tape was laminated against an aluminum foil backing. The other side was laminated against an automotive paint-coated panel to make the final test sample. The test sample was allowed to... 

Unicellular foams are used for insulation, buoyancy, and flotation applications, while multicellular foams are used for upholstery, carpet backing, and laminated textiles. Expanded PS (Styrofoam), which is produced by the extrusion of PS beads containing a volatile liquid, is used to produce low-density moldings such as foamed drinking cups and insulation boards. Foamed products are also produced from PVC, LDPE, urea resins, ABS, and PU. PU foams are versatile materials, which range from hard (rigid) to soft (flexible). These are produced by the reaction of a polyol and a diisocyanate. 

The alloys can be processed into parts requiring hydrolytic and autoclave stability, such as desalinization filter frames and medical devices. Foamed products are used in cabinets for business machines, computers, and copiers. Automotive seat backs are made by blow molding and replacements for metal parts by injection molding. 

Use (Rubber) Tires, hose, belting, and packing molded and extruded automotive and industrial products soles and heels hard rubber. (Latex) Adhesives, foamed rubber, textile and rug backing, paper coating and impregnation, modification of plastics to produce high-impact strength, asphalt additive. 

MAJOR PRODUCT APPLICATIONS carpet backing, coatings, PU-foam, pultrusion, laminates, composites, conveyor belts, cables, flooring, chipboard, tub and shower stalls, coated fabrics, electrical products, polishing, exterior cladding, tiles, synthetic marble, adliesives, coatings and sealants, sheet molding compounds, toothpaste... 

The most important application of SBR is in car tires and tire products, but there is also widespread use of the rubber in mechanical and industrial goods. SBR latexes, which are emulsions of styrene-butadiene copolymers (containing about 23-25% styrene), are used for the manufacture of foam rubber backing for carpets and for adhesive and molded foam applications. 

BP Chemicals have developed a polyurethane (PU) system for the production of integrally-molded sand-insulated carpets. The carpet is laminated with a PU backing to improve shape retention. It is then placed in a mold and PU foam is injected to fill the space between the car floor contours and the carpet. A carpet made with the system has been in use in the Fiat Turbo Uno. 

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