Binder for foundry cores

Other uses for coal-tar pitch include production as a binder for foundry cores, as a sealant for dry batteries, and in the manufacture of clay pigeons. PeUeted pitch used as the binder in foundry cores is a hard pitch suppHed as spherical granules which are formed by a spray-cooling process. Clay pigeons consist of disks molded from a mixture of hard pitch and a mineral filler such as clay or limestone dust. 

Uses. Solvent for cellulose ethers, esters, resins, and dyes liquid propellant binder in foundry cores manufacture of resins including furfuryl alcohol resin (furan resin) and furfuryl alcohol-formaldehyde resins... 

A. Binder for Foundry Sand. The major industrial use o furan resins is as a binder for foundry sand. Low levels of resin binder (0.8 to 27 ) are used to bond the sand as cores and molds for molten metal. By use of continuous mixers and appropriate levels of strong, acidic catalysts, set and strip times as low as 45 seconds at ambient temperature are attainable (see Figures 1 and 2). The furan resins work ideally in this application since they have sufficient thermal stability to retain the shape of the mold until the metal sets, then subsequently carbonize to allow shake-out of the sand after the metal hardens. 

This is an example of the use of guanidine stabilized sodium polysilicate (Si02/Na20 ratio 5 1) prepared according to Example 1 of patent application Ser. No. 287,037, filed Sept. 7, 1972, as a binder for foundry sand cores. These sand cores were used to make aluminum castings in a nonferrous metal foundry. 

Polymeric aerogels based on RF were developed in the last years for application in foundry practice as a new nanostructured binder for foundry sands. Their properties allow, for instance, to replace conventional polymeric binders, since they solve certain problems of core removal, penetration, surface reactions, blow holes, and other casting defects especially in light metal casting. RF aerogels as polymeric binders are at the verge of being used by industry. 

Other proven uses of the DBE solvents are in industrial cleaning applications, for resin cleanup in foam and molding operations, as solvents for printing inks, as textile lubricants, and as a binder in foundry cores. 

Foundry Resins. In the foundry industry, phenoHc resins are used as the binder for sand in the manufacture of sheU molds and cores. The two mating halves are joined by clamps or a bonding agent to form a sheU mold into which the molten metal is poured for castings. The sheU is formed by depositing a resin—sand mix on a hot metal pattern plate. After a certain period the pattern is inverted and the excess resin sand is removed. The sand particles are bonded by an oven cure, and the sheU is ejected from the pattern plate. 

Water-borne adhesives are preferred because of restrictions on the use of solvents. Low viscosity prepolymers are emulsified in water, followed by chain extension with water-soluble glycols or diamines. As cross-linker PMDI can be used, which has a shelf life of 5 to 6 h in water. Water-borne polyurethane coatings are used for vacuum forming of PVC sheeting to ABS shells in automotive interior door panels, for the lamination of ABS/PVC film to treated polypropylene foam for use in automotive instmment panels, as metal primers for steering wheels, in flexible packaging lamination, as shoe sole adhesive, and as tie coats for polyurethane-coated fabrics. PMDI is also used as a binder for reconstituted wood products and as a foundry core binder. 

Most furfural is produced from corncobs and oat and rice hulls, primarily by the Quaker Oats Company. The product is used in the chemical industry as a solvent and in wood rosin refining. A large amount of furfural is treated further to give furfuryl alcohol. The furfuryl alcohol is added to urea-formaldehyde resins in applications for adhesives and foundry core binders. 

Mullers can be used if the paste is not too fluid or sticky. The main application of muller mixers is now in the foundry industry to mix small amounts of moisture and binder with sand for both core and molding sand. Muller mixers also handle such diverse materials as... 

Use Binder for carbon electrodes, base for paints and coatings. Impregnation of fiber pipe for electrical conduits and drainage, foundry core compounds, briquetting coal, tar-bonded refractory brick, paving and roofing, plasticizers for elastomers and polymers, extenders, saturants, impregnants, sealants. 

The viscosity of caramel allows its employment as an adhesive and binder for instant sand-molds and foundry core for producing difiicultly accessible, hollow cavities in castings. Caramel binds together a sodium chloride, quartz, or metal-powder matrix to a mass that binds to aluminum or aluminum-alloy castings. On casting, such a binder produces only a small volume of combustion gases. The cores are readily removed, either mechanically or by dissolution. ... 

The use of polyurethane as a binder has found two interesting applications foundry cores and woodchip particleboard. The foundry industry has recognized the value of polyurethane adhesive binders to bind sand foundry cores for metal casting. This application is increasing steadily. The use of isocyanate binders for woodchip particleboard is receiving significant attention. The... 

In order for the foundry core or mold to become weak after heating and cooling, it is helpful to have crystalline silica such as cristobalite formed throughout the binder mass by spontaneous nucleation at high temperatures. Such nucleation apparently occurs at the surface of... 

Pitch is a material resistant to moisture absorption and is often used as a binder or as an additive for foundry sand cores and molds. 

Foundry core binders are isocyanate-cured alkyd or phenolic adhesives used as binders for sand used to produce foundry sand molds. These sand molds are used to east iron and steel parts. A fast, economical cure of the sand mold is required under ambient conditions. 

Chem. Descrip. Blend of dimethyl esters of glularic (55-65%), succinic adds (15-25%), and adipic (12-23%) adds Uses Solvent for inks, coating, deaning diems., paint strippers, foundry core binders, hand cleaners, textile lubricants, pesticides, insectiddes, seaiants and waxes... 

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