• Coefficient of Friction

A measure of the amount of resistance that a surface exerts on or substances moving over it, equal to the ratio between the maximal frictional force that the surface exerts and the force pushing the object toward the surface. The coefficient of friction is not always the same for objects that are motionless and objects that are in motion; motionless objects often experience more friction than moving ones, requiring more force to put them in motion than to sustain them in motion. The static coefficient of friction is the coefficient of friction that applies to objects that are motionless. The kinetic or sliding coefficient of friction is the coefficient of friction that applies to objects that are in motion.

• Coef. of Thermal Expansion

The fractional change in dimension (sometimes volume) specified of a material (plastic, metal or other materials) per a unit change in temperature.

• Colourants

Are additive used to change the color of the plastic. They can be a powder or a resin/color premix.

• Composite

A structural material consisting of a combination of materials. Typically, one of the materials is a strengthening agent, the other being a thermoset or thermoplastic resin.

• Compressive Strength

Crushing load at the failure of a specimen divided by the original sectional area of the specimen.

• Concentration

Amount of solute per unit volume or mass of solvent or of solution.

• Conditioning

The subjection of a material to a stipulated treatment so that it will respond in a uniform way to subsequent testing or processing. The term is frequently used to refer to the treatment given to specimens before testing.

• Conductivity

a measure of a material's ability to conduct an electric current

• Contact Adhesive

An adhesive that .is apparently dries to touch and that will adhere to itself simultaneously upon contact

• Continuous Service Temperature

The highest temperature at which a material can perform reliably in long term application - long term being, however, inconsistently defined by the manufacturers.

• Conveyor

A mechanical device to transport material from one point to another, often continuously.

• Corona Treatment

Corona treating is a very effective way to increase the surface tension of virtually any material. The result after corona treatment is a surface that is unchanged to the naked eye, but in fact is much more receptive to inks, coatings, and adhesives. The material being treated is exposed to an electrical discharge, or "corona." Oxygen molecules within the discharge area break into their atomic form and are free to bond to the ends of the molecules in the material being treated, resulting in a chemically activated surface.

• Corrosion

Oxidation of metals in the presence of air and moisture.

• Corrosive Wear

Wear caused by the attack of various acids on the surface of screws, barrels, valves and other processing components. Acids formed in the processing of plastic erode and pit the metal surfaces. The acids come from the polymers themselves or from flame retardants, forming and coupling agents.

• Curing Time

It is the period of time during which a part is subjected to heat (or pressure), or both, to cure the resin. It is an interval of time between the instant of cessation of relative movement between the moving parts of a mold and the instant that pressure is released. (Further cure may take place after removal of the assembly from the conditions of heat or pressure.)

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