Slush molding plastisols

Slush Molding. This is the reverse of dip molding. A female mold is used to give any desired surface finish on the product. The mold is preheated, plastisol is pour into it, and gels onto the surface of the mold. The excess liquid plastisol is poured out, and the internally- coated mold is heated to gel, then cooled to solidify the rubbery product, and the product is stripped out of the mold. Typical products are arm rests, head rests, road safety cones, anatomical models, dolls, toys, and auto parts. 

Slush molding is used mainly with plastisols. It is usually a continuous operation. The mold (female) is filled above a specific pattern mark and passed through an oven that sets or gels the material in contact with the metal mold surface. These molds are electroformed copper or cast aluminum. The material in the center of the mold that is still a fluid is poured out of the mold with the mold returning to an oven for final fusion. Upon removal from the fusion oven, the mold is cooled and the finished product is stripped from the mold. Vacuum or compressed air can be used with large parts or with those of a complex geometry to assist in product removal. One part of the mold must be open to the atmosphere to permit pouring and product removal. 

The effect of the presence of compatibilized incompatible components is apparent in PVC plastisols. Monomeric and polymeric esters are good plasticizers for PVC because they have suitable solubility parameters. A good plasticizer is one which, in sufficient quantity, would almost be a solvent for the polymer. However, a good plasticizer, i.e. solvent, in a plastisol results in a high viscosity composition. This may be unsuitable for slush molding or other applications when low viscosity is desirable. The latter is obtained by adding a secondary plasticizer such as a hydrocarbon oil. In reality, the latter is not a plasticizer but actually a non-solvent which converts the good solvent plasticizer to a poor solvent mixture with resultant decrease in plastisol vis-... 

Slush molding is a similar molding technique to dip molding used in PVC processing. The difference is that plastisol is poured into the mold (in dip molding the mold is inserted into a plastisol), and the mold is heated to gel and fuse plastisol. Some available inventions are discussed below. 

CAS 471 -34-1 EINECS/ELINCS 207-439-9 Uses Filler for painfs, enamels, plastisols esp. slush molded pads requiring high gloss, polyolefin compds. for sheet stock, thin films, paper coatings, rubber prods., upholstery fabrics, credit card stock, pigment extenders, caulks, sealants, and adhesives Features General purpose... 

Uses Plasticizer for flooring, cast and calendered free film and sheeting, extnjsion, slush molding, inks, coatings, adhesives, sealants, elastomers, plastisols, wire and cable Regulat DOT regulated... 

PVC plastisols are suspensions of PVC resin in a hquid phase mainly constituted by the plasticizer and the stabilizer. Plastisols can be processed by different techniques, such as rotational casting, slush molding, dip molding, dip coating, or spray coating. In these pro-... 

Slush molding Used to create hollow, flexible items. A quantity of plastisol is poured into a heated female mold, causing gelling of the plastisol directly in contact with the heated surfaces. The excess plastisol is poured off and the gelled layer is allowed to fuse. After fusing, the finished item is removed from the mold. 

In slush molding process of footwear articles, di-(2-ethylhexyl) phthalate is rrsed for inexpensive footwear. A good eorrrpatibility with polyurethane is expected to reduce fogging in dashboard applications. In these inventions, it is expected that polyetlylene glycol dibenzoate helps to achieve these properties. In some cases, addition of a resinotrs component is expected to improve plasticizer retention. Plastisol composition includes nitrile rubber, which improves extraction resistance of plasticized compositioa ... 

Slush molding is often used with PVC plastisols, and it is like dip coating in that a hot mold is filled with plastisol and the material is immediately poured out. The... 

Mixing Liquids. Carriers like mineral oil and plastisol are typical. Mineral oil is used in a variety of liquid color application. Plastisols find use in calendered and slush-molded PVC applications. The process provides good mixing but a low level of dispersion. Some of these blends are suitable for end-use appHcations. Most are milled to provide a higher quality of dispersion. 

Slush molding uses plastisols (dispersions of thermoplastic polymers in liquid plasticizers 50-100 parts plasticizer to 100 parts polymer). A hollow mold filled with the plastisol is carried on a conveyor belt through an oven (temperature 500-600T). Excess liquid is then poured out. The mold goes next to a second oven, where the curing is finished. This technique, used for toys, produces a product with fine details. 

Butyl benzyl phthalate is a plasticizer added to polymers to give flexibility and softness. It is used extensively in polyvinyl chloride and in cellulose plastics, polyvinyl acetate, polysulfides, and polyurethane. Also used in flexographic inks for food packaging applications and acrylic coatings, profile extrusions, slush molding, film and sheeting, coated fabrics, floor and wall coverings, vinyl foams, and plastisols for car sealants. 

Slush molding is a mnq>le variation of the casting process. The low-viscosity material, such as, plastisol is poured into a hot mold and after a thick casting is formed on the wall of the mold cavity, the excess material is poured out. In order to ensure uniform coating, the mold is often rotated. 

The precise amount of plastisol needed for the part is put into the mold and the mold is closed. There are no openings in the mold, which is attached to a device capable of rotating in all dimensions to create a uniform internal coating. The arm and mold are put in an oven for fusion. Once the material is fused and cooled the mold is opened and the part removed. Balls and doll heads— and other nearly round parts— are most often rotomolded. Part properties are the same as that for slush molding. 

By virtue to its contribution to low viscosity and good viscosity stability, Palatinol N is suitcible for plastisols including spray coating, dipping, casting, or slush molding. 

Similar procedures have been in use for years with plastisols (Chapter 7). Liquid platisol is poured into a heated female mold. The plastisol in contact with the mold surface fuses and the remainder is poured out for reuse. This slush-molding process is used to produce objects such as doll s heads. Dipping a heated object into a liquid plastisol coats it with plasticized polymer. Vinyl-coated wire dishracks are familiar products of this process. 

Plastisols and organosols - PVC powders are dissolved in solvent (organosol) or dispersed in plasticizer (plastisol), and fillers are added in conventional slow speed mixers. The resultant viscous liqtrids arc used to rotationally cast, slush mold or dip articles. Mineral fillers arc used to increase stifihess and hardness, reduce tackiness and reduce costs, although they may increase viscosity and reduce shelf life. 

Slush molding uses liquid polymers (plastisols) for small hollow parts. 

Low to medium viscosity at low shear rates and the absence of thixotropy are normally desirable characteristics for slush molded plastisol formulations. These formulation traits will facilitate drainage after the gelation step and leave a part with a minimum of drip and run marks on the interior skin surface." Resin selection can help yield plastisols with these desired rheological characteristics. 

Slush molding of plastisols is primarily used to produce rainboots and overshoes, and secondarily for toy and doU parts, and for automotive interior skin coats. The secondary uses are popular where circumstances such as short mns of many variations militate against rotational molding. The molds, typically low-cost aluminum, are preheated to a temperature at which the plastisol will gel rapidly, then filled with plastisol. After a brief gelation time, the molds are emptied of excess plastisol and placed in a fusion oven, then cooled to permit demolding. 

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