thermoforming

Polyethylene terephthalate (aka. PET, PETE, PETP) is a thermoplastic resin of the polyester family that is used to make beverage, food and other liquid containers, synthetic fibers, as well as for some other thermoforming applications. It is also one of the most important raw materials used in man-made fibers. Depending on its processing and thermal history, it may exist both as an amorphous (transparent) and as a semi-crystalline (opaque and white) material. It can be synthesized by a transesterification reaction ...

Including:

• Polyethylene terephthalate - Uses
• Polyethylene terephthalate - Intrinsic viscosity
• Polyethylene terephthalate - Drying
• Polyethylene terephthalate - Copolymers
• Polyethylene terephthalate - Crystals
• Polyethylene terephthalate - Degradation
• Polyethylene terephthalate - Re-crystallization experiment
• Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia - Polyethylene terephthalate

Solid modelling - Parametric Solid modelling CAD. Solid modellers have become commonplace in engineering departments in the last ten years due to faster PCs and competitive software pricing. They are the work horse of machine designers. Solid modelling software creates a virtual 3D representation of components for machine design and analysis. Interface with the human operator is highly optimized and includes programmable macros, keyboard shortcuts and dynamic model manipulation. The ability to dynamically re-orient the model, in Real-time shaded 3-D, is emph ...

See also:

Solid modelling, Solid modelling - Basic theoretical concepts, Solid modelling - History, Solid modelling - Practical applications, Solid modelling - Parametric Solid modelling CAD, Solid modelling - Entertainment, Solid modelling - Medical solid modelling

Read more here: » Solid modelling: Encyclopedia II - Solid modelling - Practical applications

The main virtue of PET is that it is fully recyclable. Unlike other plastics, its polymer chains can be recovered for additional use. PET has a resin identification code of 1. PET can be semi-rigid to rigid, depending on its thickness, and is very lightweight. It makes a good gas and fair moisture barrier, as well as a good barrier to alcohol (requires additional "Barrier" treatment) and solvents. It is strong and impact-re ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Uses

One of the most important characteristics of PET is referred to as I.V.(Intrinsic Viscosity) The IV of the material, measured in dl/g (deci liters/gram) is dependent upon the length of its polymer chains. The longer the chains, the stiffer the material, and therefore the higher the IV. The average chain length of a particular batch of resin can be controlled during polymerization. An IV of about: 0.60 - would be appropriate for fiber 0.65 - ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Intrinsic viscosity

PET is hygroscopic, meaning that it naturally absorbs water from its surroundings. However when this 'damp' PET is then heated a chemical reaction known as hydrolysis takes place between the water and the PET which reduces its molecular weight (IV) and its physical properties. This means that before the resin can be processed in a molding machine, as much moisture as possible must be removed from th ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Drying

There are two basic molding methods, one-step and two-step. In two-step molding, two separate machines are used, one for injection molding the perform, the second for stretch-blow molding it into the final container shape. In one-step machines, the entire process from raw material to finished container is conducted within one machine, making it especially suitable for molding non-standard shapes (custom molding), including jars, flat oval, flask shapes etc. Its greatest merit is the reduction in space, product handling and energy, and far higher visual quality than can be achieved by the two-step system. Sin ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Processing Equipment

In addition to pure (homopolymer) PET, PET modified by copolymerization is also available. In some cases, the modified properties of copolymer are more desirable for a particular application. For example, cyclohexane dimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol. Since this building block is much larger (6 additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighboring chains the way an ethylene glycol unit would. This interferes with crys ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Copolymers

Solid modeling has to be seen in context of the whole history of CAD, the key milestones being the development of Romulus which went on to influence the development of Parasolid and ACIS and thus the mid-range Windows based feature modelers such as Solid Works and Solid Edge and the arrival of parametric solid models system like T-Flex and Pro/Engineer. ...

See also:

Solid modelling, Solid modelling - Basic theoretical concepts, Solid modelling - History, Solid modelling - Practical applications, Solid modelling - Parametric Solid modelling CAD, Solid modelling - Entertainment, Solid modelling - Medical solid modelling

Read more here: » Solid modelling: Encyclopedia II - Solid modelling - History

There are two basic molding methods, one-step and two-step. In two-step molding, two separate machines are used, one for injection molding the preform, the second for stretch-blow molding it into the final container shape. In one-step machines, the entire process from raw material to finished container is conducted within one machine, making it especially suitable for molding non-standard shapes (custom molding), including jars, flat oval, flask shapes etc. Its greatest merit is the reduction in space, product handling and energy, and far higher visual quality than can be achieved by the two-step system. Sin ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Processing Equipment

One of the most important characteristics of PET is refered to as I.V.(Intrinsic Viscosity) The IV of the material is dependent upon the length of its polymer chains. The longer the chains, the stiffer the material, and therefore the higher the IV. The average chain length of a particular batch of resin can be controlled during polymerization. An IV of about: 0.6 - would be appropriate for fiber 0 ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Intrinsic viscosity

PET is hygroscopic, meaning that it naturally absorbs water from its surroundings. However, before the resin can be processed in a molding machine, all moisture must be removed from the resin. This is achieved through the use of a dryer. Inside the dryer, the air is run through an after cooler, because it is easier to remove moisture from cold air than hot air. The air is then dispersed into a dessicant bed. The air leaving the dessicant bed is cool and dry. The air then flows through a process heater. After that hot dry air is pumped ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Drying

In addition to pure (homopolymer) PET, PET modified by copolymerization is also available. In some cases, the modified properties of copolymer are more desirable for a particular application. For example, cyclohexane dimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol. Since this building block is much larger (6 additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighboring chains the way a ethylene glycol unit would. This interferes with crys ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Copolymers

Crystallization occurs when polymer chains fold up on themselves in a repeating, symmetrical pattern. Long polymer chains tend to become entangled on themselves, which prevents full crystallization in all but the most carefully controlled circumstances. PET is no exception to this rule; 60% crystallization is the upper limit for commercial products, with the exception of polyester fibers. PET in its natural state is a crystalline resin. We are able to produce clear products by rapidly cooling molten polymer to form an amorphous solid. ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Crystals

When PET degrades, several things happen, mainly the formation of acetaldehyde and cross-links ("gel" or "fish-eye" formation). Acetaldehyde is normally a colorless gas with a fruity smell. It forms naturally in fruit, but it can cause an off-taste in bottled water. Acetaldehyde forms in PET through the "abuse" of the material. High temperatures (PET decomposes above 300°C or 572°F), high pressures, extruder speeds (excessive shear flow raises temperature) and long barrel residence times all contribute to the production of acetaldehyde. Wh ...

See also:

Polyethylene terephthalate, Polyethylene terephthalate - Uses, Polyethylene terephthalate - Intrinsic viscosity, Polyethylene terephthalate - Drying, Polyethylene terephthalate - Copolymers, Polyethylene terephthalate - Crystals, Polyethylene terephthalate - Degradation, Polyethylene terephthalate - Re-crystallization experiment, Polyethylene terephthalate - Processing Equipment

Read more here: » Polyethylene terephthalate: Encyclopedia II - Polyethylene terephthalate - Degradation