Pimpex Plastic, China presents the definition, characteristics
and classification of plastics for your reference.
The definition of plastic
- Plastic refers to those materials which could flowage molding during
machining process, plastic mainly consists of resin,
rosin,
colophony
(or directly polymerized from monomers during machining process), plastic
also consists of some additives as assistant components such as plasticizer,
filling
materials, lubricant,
colorant,
etc.
The characteristics of plastic:
- Most plastic have light weight, chemical stability, stainless
- Good impact resistance
- Good transparent and wearable performance
- Good electric isolation and low heat exchange rate
- Good molding and good colorization performance, low machining cost
- Most plastic are poor in heat resistant, with higher heat expansion
rate and easily burnt
- Poor sizes stability, easily distortion
- Most plastic are poor in low temperature resistant, easily turned
into brittle at low temperature
- Easily aging
- Some plastic are easily solved in solvent
The classification of plastic:
- Plastic could be classified by its usage characteristics, physical
and chemical performances or machining methods.
Plastic classification by usage characteristics:
Universal Plastic
- Universal Plastic refers to those plastic of large output capacity,
wide application fields, good molding performance, cheap prices, such
as Polyethylene
(PE), Polypropylene
(PP), Phenolics,
Bakelite,
etc.
Engineering Plastic
- Engineering Plastic refers to those plastic which could bear some
extend of outer forces, have good mechanical performance, high temperature
resistant, low temperature resistant, good sizes stability, could be
used as engineering structural frameworks, such as polyamide,
polysulfone
(PSF), etc.
- Engineering Plastic could be classified further into two types: Universal
Engineering Plastic, Special Engineering Plastic
Special Plastic
- Reinforced
Plastics: Reinforced plastics could be classified according to
its shapes into granular type (such as Ca-plastic reinforced plastics),
fiber type (such as fiberglass
reinforced plastics or fiber cloth reinforced plastics) and sheet
type (such as mica reinforced plastics). Reinforced plastics could
be classified according to its materials into cloth basis reinforced
plastics (such as rag reinforced plastics or asbestos reinforced plastics),
inorganic minerals filled
plastics (such as quartz or mica filled plastics) and fiber
reinforced plastics (such as carbon
fiber reinforced plastics).
- Foam
Plastics: Foam Plastics could be further classified into hard
foam plastics, half hard foam plastics and soft foam plastics. Hard
foam plastics have not flexility, large compression hardness, which
would be only distorted under some certain stress value and could
not recover to its former figures. Soft foam plastics have good flexility
and little compression hardness which could be easily distorted while
could recover to its former figures with little distortion remained
when the stress are released. The flexility and others performances
of half hard foam plastics are between hard foam plastics and soft
foam plastics.
Plastic classification by physical and chemical performances:
Thermosetting
Plastics:
- Thermosetting Plastics, or Thermoset Plastics refer to those plastics
which would be solidified or could not be melted easily when they are
heated, such as bakelite,
phenolplast,
epoxy
plastic.
- Thermosetting Plastics, or Thermoset Plastics have two types, one
is methanal cross linked type, such as bakelite, phenolplast, aminoplastic;
another is others cross linked type, such as unsaturated
polyester, ethoxyline
resin, diallyl
phthalate resin, etc.
Thermoplastic:
- Thermoplastic refer to those plastics which could be reused time
after time within some temperature range, such as polyethylene
(PE), polypropylene (PP), polycarbonate (PC), polytetrafluoroethylene
(PTFE),
etc. Thermoplastic could be further classified into hydrocarbon type,
ethylene type with polarity structure, engineering type, cellulose type,
etc.
- Hydrocarbon Type Plastics: Hydrocarbon type plastics belong to
nonpolarity plastics which could be further classified into crystalline
hydrocarbon type plastics and non crystalline hydrocarbon type plastics.
Crystalline hydrocarbon type plastics includes polyethylene
(PE) and polypropylene
(PP), etc. Non crystalline hydrocarbon type plastics includes polystyrene
(PS),etc.
- Ethylene Type Plastics with Polarity Structure: Except for fluorine
plastic, most ethylene type plastics with polarity structure are
non crystalline transparent body, including polyvinyl
chloride (PVC), polytetrafluoroethylene
(PTFE), polyvinyl
acetate, etc. Most of ethylene type monomer could be polymerized
by adopting free radical type catalyzers.
- Thermoplastic
Engineering Plastics: Thermoplastic engineering plastics mainly
includes polyoxymethylene (POM),
polyamide (PA),
polycarbonate (PC),
acrylonitrile-butadiene-styrene (ABS),
polyphenyleneoxide (PPO),
polyethylene
glycol terephthalate, polysulfone (PSF),
polyethersulfone (PES),
polyimide (PI),
polyphenylenesulfide (PPS),
etc. Polytetrafluoroethylene (PTFE),
modified
polypropylene could also be classified as thermoplastic engineering
plastics.
- Thermoplastic Cellulose Plastics: Thermoplastic cellulose plastics
mainly includes cellulose
acetate, acetyl
cellulose, cellulose
acetate butyrate, celluloid,
cellophane,
etc.
Plastic classification by machining methods:
- According to different machining methods of all kinds of plastic,
plastic could be classified into several types: Film Pressure Plastic,
Laminating Plastic, Injection Plastic, Extrusion Plastic, Blow Molding
Plastic, Cast Plastic and Reaction Injection Molding Plastic, etc.
- Film Pressure Plastic refers to those plastics
whose physical machining performances are similar with common solidity
plastics;
- Laminating Plastic refers to those fabric materials
dipped with resin and then folded, hot pressed into integral entity;
- Injection
Plastic, Extrusion Plastic and Blow
Molding Plastic refer to those plastics whose physical and machining
performances are similar with common thermoplastic plastics;
- Cast Plastic refers to liquid mixture resin which
could be harden and molded into finished products without pressure
or little pressure when they are poured into moulds, such as nylon,
etc.
- Reaction Injection Molding Plastic refers to those
liquid plastic raw materials which could be injected into female mould
cavities with some pressure and then reacted and solidified into finished
products, such as polyurethane (PU),
etc.
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