Wax Is the Oldest Thermoplastic Material Known to Man

What is Wax?

- Wax is the oldest thermoplastic material known to man.

- Can be Cast/Injected as a: Liquid, Solid, or Paste.

- Originally only beeswax was used. People have recently discovered that rice wax and coconut wax may be used as well.

- Wax is a blend of amorphous and crystalline materials including:

- Paraffins

- Microcrystallines

- Resins

- Natural Waxes

- Modifiers

- Fillers

- These ingredients impart specific characteristics to the wax. Subsequently, these unique properties of wax drive many of the process control requirements in Investment Casting.

- There are various different types of waxes used in Investment Casting including:

- Pattern Waxes (Filled/Non-Filled)

- Gating

- Specialty Waxes

- Reclaimed Waxes

- To control viscosity use synthetic wax or petrochemical wax.

- Daido uses 11 elements to make up a runner’s wax plus 6-8% filler.

- Some waxes can even have up to 15 elements making up the wax.

Viscosity

Paraffins

Paraffin may contain up to 8 different ingredients. It has good flow and is easy to mix. Paraffin is also very cheap, Blayson uses two types. 135°F and 155°F.

Definition:

Paraffin Wax [Mater] A solid, crystalline hydrocarbon mixture derived from the paraffin distillate portions of crude petroleum; used in paper coating, candles, creams, emollients, and lipstick. Also known as ceresin wax; paraffin.

Microcrystallines

Microcrystalline Wax is a waste from the cracking of petroleum viscosity. Blayson uses two types of this wax.

Definitions:

Microcrystalline Wax [Mater] A petroleum wax containing small, indistinct crystals, and having a higher molecular weight, melting point, and viscosity than paraffin wax; used in laminated paper and electrical coil coating.

Resin/Rosin

Resin is a natural tree hydrocarbon secretion that sets hard to control shrinkage. Rosin is chemically treated resin used as hardeners. There are eight types.

Definitions:

Resin: 1) Any of numerous clear to translucent yellow or brown, solid or semisolid, viscous substances of plant origin, such as copal, rosin, and amber, used principally in lacquers, varnishes, inks, adhesives, synthetic plastics, and pharmaceuticals. 2) Any of numerous physically similar polymerized synthetics of chemically modified natural resins including thermoplastic materials such as polyvinyl, polystyrene, and polyethylene and thermosetting materials such as polyesters, epoxies, and silicones that are used with fillers, stabilizers, pigments, and other components to form plastics.

Rosin: A translucent yellowish to dark brown resin derived from the stumps of sap of various pine trees and used to increase sliding friction, as on the bows of certain stringed instruments, and to manufacture a wide variety of products including varnishes, inks, linoleum, adhesives, and soldering compounds.

Hydrocarbon: Any of numerous organic compounds, such as benzene and methane that contain only carbon and hydrogen.

Hydrocarbon Resins [Org Chem] Brittle or gummy materials prepared by the polymerization of several unsaturated constituents of coal tar, rosin, or petroleum; they are inexpensive and find uses in rubber and asphalt formulations and in coating and caulking compositions.

Natural Waxes

Candelilla Wax comes from leaves in Mexico. It is very expensive. Carnoba Wax from leaves for set rate and viscosity. It increases the strength and improves the surface finish. However, it is very costly.

Definitions:

Candelilla Wax [Mater] A wax obtained from the wax-coated stems of Candelilla shrubs, especially Euphorbia anti-syphilitica; used for varnishes and furniture and shoe polishes.

Modifiers

Wax manufacturers add modifiers and we do not know what they are.

Fillers

Adding fillers to wax generally increases the viscosity of the blend. Therefore, filled waxes are usually designed with a higher amount of paraffin and/or microcrystalline wax than non-fillers. In addition, filled waxes also have higher specific gravity and lower ring and ball softening points compared to non-filled waxes. The degree of difference will depend on the amount and type of filler.

Definitions:

Bisphenol [Org Chem] (CH3)2C(C6H5OH)2 Brown crystals that are insoluble in water; used in the production of phenolic and epoxy resins. Also known as p,p1-dihydroxydiphenyldimethylene.

Isophthalic Acid [Org Chem] C6H4(COOH)2 Colorless crystals subliming and 345°C; slightly soluble in water, soluble in alcohol and acetic acid, and insoluble in benzene; used as an intermediate for polyester and polyurethane resins, and as a plasticizer. Also known as meta-phthalic acid.

Polystyrene [Org Chem] (C6H5CHCH2)x A water-white, tough synthetic resin made by polymerization of styrene; soluble in aromatic and chlorinated hydrocarbon solvents; used for injection molding, extrusion or casting for electrical insulation, fabric lamination, and molding of plastic objects.

Note: Cross-linked polystyrene is normally used as a dielectric material due to its dimensional stability and high quality. The difference between polystyrene and cross-linked polystyrene is that the latter is harder and capable of withstanding higher temperatures.

Terephthalic Acid [Org Chem] C6H4(COOH)2 A combustible white powder, insoluble in water, soluble in alkalies, sublimes above 300°C; used to make polyester resins for fibers and films and as an analytical reagent and poultry-feed addititve. Also known as benzene-para-dicarboxylic acid; para-phthalic acid; TPA.

Other

Definitions:

Collophane [Mineral] A massive, cryptocrystalline, carbonate-containing variety of apatite and principal source of phosphates for fertilizer. Also known as collophanite.

Differential Scanning Calorimetry[DSC] A thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature.

Dilatancy [Chem] The property of a viscous suspension which sets solid under the influence of pressure. [Geol] Expansion of deformed masses of granular material, such as sand, due to rearrangement of the component grains.

Graphitic Carbon [Met] Carbon in iron or steel present in the form of graphite.

Newtonian Flow [FL Mech] Flow system in which the fluid performs as a Newtonian fluid, that is, shear stress is proportional to shear rate.

Newtonian Fluid [FL Mech] A simple fluid in which the state of stress at any point is proportional to the time rate of strain at that point; the proportionality factor is the viscosity coefficient.

Newtonian Friction Law [FL Mech] The law that shear stress in a fluid is proportional to the shear rate; it holds only for some fluids, which are called Newtonian. Also known as Newton formula for the stress.

Non-Newtonian Fluid [FL Mech] A fluid whose flow behavior departs from that of a Newtonian fluid, so that the rate of shear is not proportional to the corresponding stress. Also known as Non-Newtonian System.

Non-Newtonian Fluid Flow [FL Mech] The flow behavior of Non-Newtonian Fluids, whose study has applications in many important problems of practical significance such as flow in tubes, extrusion, flow through dies, coating operations, rolling operations, and mixing of fluids.

Rheology [Mech] The study of the deformation and flow of matter, especially non-Newtonian flow of liquids and plastic flow of solids.

Thixotropy [Phys Chem] Property of certain gels which liquefy when subjected to vibratory forces, such as ultrasonic waves or even simple shaking, and then solidify again when left standing.

Batch to Batch Variation

Low Melt U281 and O191 Viscosity (cP) vs. Temperature (̊F)

Low Melt U281 and O191 Viscosity (cPs) vs. Temperature (̊F) (Second Test Run)

U281 and O191 Viscosity (cPs) vs. Temperture(̊F)(0-2000 cps)

DSC Graph of U281 and O191 Power (mW) vs. Temperature (̊F)

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