Plastics normally consist of basic polymers and additives. The additives give the plastic different properties. Additives are, for example, UV-protection agents, colourants, fillers, reinforcers, and softeners.
Plastics can be divided in to three groups: bulk plastics, technical plastics, and specialized plastics. Additionally, plastics are divided into thermoplastic polymers and thermosetting plastics. The latter division is based on the processing properties of the plastics: thermoplastic polymers can be remelted and reshaped, while thermosetting plastics cannot. Thermoplastic polymers are further divided by their chemical properties into amorphous and semi-crystalline.
Bulk plastics, technical plastics and specialized plastics
Bulk plastics are cheap and are used in great quantities. The technical properties of bulk plastics aren’t very good, but are sufficient for many uses. Bulk plastics are widely used in different consumer products. The technical plastics used in more demanding products have better technical properties than bulk plastics. Technical plastics are more expensive than bulk plastics. Specialized plastics are even more advanced than technical plastics.
Thermosetting plastics cannot be reused. They are manufactured using heat, by hardening liquid resin and a hardening agent. Thermosetting plastics usually have good heat resistance and they are also mechanically durable. Several thermosetting plastics also have very good electrical properties. The down side of using thermosetting plastics is the slowness of the manufacturing process and the lower recyclability of the raw material for reuse or energy.
Types of thermosetting plastics
Polyurethanes (PUR): Used, for example, for insulation, mattresses, and seats.
Unsaturated polyesters (UP): Often called fibreglass. Used, for example, for boats, cars, containers, pools, pipes, ship and train parts, cultured marble, panels, profiles, and rods.
Epoxides (EP): Strong plastics that have good heat and chemical resistance. Used, for example, for sports equipment, car parts, and in the aerospace industry.
Vinyl esters (VE): More flexible than most other thermosetting plastics, very good chemical durability. Used, for example, for industrial containers and pipes, chimneys, and sewage treatment pools.
Phenol–formaldehydes (PF): Excellent resistance to high temperatures. Used, for example, in the automotive and aircraft industries.
Aminoplastics (MF and UF): Hard and rigid, good impact resistance. Aminoplastics are also fire resistant.
Thermoplastic polymers can be reused. They have thermoplastic properties meaning that the plastic softens when heated and it can be reshaped. Thermoplastic polymers are divided into amorphous and semi-crystalline plastics based on their chemical structure.
Amorphous thermoplastic polymers
Amorphous plastic doesn’t have a melting point. It softens slowly when heated. This property enables the amorphous plastics to be shaped using heat. Amorphous plastics have smaller mould and after shrinkage and a smaller tendency for warping than semi-crystalline plastics.
Semi-crystalline thermoplastic polymers
Semi-crystalline plastics go completely liquid once they reach their melting point. Because semi-crystalline plastics do not soften when heated, they generally have a higher heat resistance than amorphous plastics. Semi-crystalline plastics also have better fatigue resistance and chemical resistance than amorphous plastics.
Types of thermoplastic polymers
Acrylic, PMMA: Due to good light penetrability it is used, for example, for illuminated advertisements and aquariums. Acrylic is also used in paints.
Polyethylene PE-LD: A widely used plastic. Used, for example, for plastic bags and string.
PE-HD: Used, for example, for pipes, buckets, bottles, and toys.
Polypropylene, PP: Very good chemical resistance. Used, for example, for membranes, fibres, ropes, and plates.
Polystyrene, PS: Good mouldability and dyeability. Good electrical insulator. Used, for example, for dishes, toys, casings, and boxes.
Polyethylene terephthalate, PET: Especially widely used in the packaging industry, for example for soda bottles.
Polyvinyl chloride, PVC: Excellent water resistance. Used, for example, for pipes, rain coats, and bags. Also used as an electrical insulator.
Polyamide, PA: Widely used in the clothing industry. Also used, for example, for rugs and ropes. The most well-known polyamide is nylon.
Polycarbonate, PC: An easily workable and impact resistant plastic. Used, for example, for lenses for sunglasses, CDs, riot shields, and safety goggles.
Polylactide, PLA: A biodegradable plastic made from renewable raw materials. Used, for example, for 3D-printing.
Polytetrafluoroethylene, PTFE: Used in various coatings, for example the Teflon coating of frying pans.
Polyoxymethylene or polyacetal, POM: Used, for example, for screws and cogwheels
Ethylene chlorotrifluoroethylene, ECTFE: Used, for example, for pipes and container coatings.
Polyvinylidene difluoride, PVDF: Used, for example, for bearings, pipes, and microchips
Acrylonitrile–butadiene–styrene, ABS: Used, for example, in home and office appliances.
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Leomuovi has been delivering injection molded parts and goods to both industry and consumers for more than 30 years. Leomuovi’s main focus is on contract manufacturing and our services are used in numerous industries, for example:
We use the latest technology and methods to ensure optimal results. For manufacturing plastic products and components, we use injection moulding, which is best suited for manufacturing large series. For sealing, we use an automated production line, which ensures the high quality and repeatability of products.
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Thanks to our joint efforts and enthusiasm to create valuable products, Leomuovi Oy is growing sustainably and continuously. Nowadays our factory manufactures a broad palette of customized industrial components and appliances from different commodity and engineering plastics.