Plastic Material Classifications
“Plastic material” is a term that refers to a large class of polymers, separated into various groups and sub-groups. Before starting the chapter on the uses and subsequent recycling of plastic, let us establish a general classification of these thermosetting resins or thermo-plastics (the two big groups into which we include elastomers) by detailing their properties, their make-up, their aspect, and their final uses, while explaining which ones are recyclable.
Remember that thermoplastic is a material whose structure and viscosity can be modified both ways through heating or cooling. This large family of materials is commonly used by many industries and is easily integrated into France’s recycling cycles. The following polymers are some examples of plastic material:
This type of plastic includes materials such as polyethylene (PE, the world’s most commonly used thermoplastic resin), ethylene vinyl acetate copolymers (EVA), as well as polypropylene (PP) which, like PE, is processed by Paprec’s recycling factories.
Obtained through the polymerisation of ethylene, polyethylene is a waxy solid, colourless and odourless. It is soluble at 60 to 80°C in some organic solvents, and is not usually plasticised.
Polyethylene comes in two types: low density PE (LDPE), and high density PE (HDPE).
It is used to make plastic bags, cling films (future recyclable plastic waste), flasks, bottle containers, toys, buckets, basins, flexible tubing, or cisterns. Tupperware also contains PE. Bags for industrial use, household waste, or bottles for cleaning products are commonly made from recycled LDPE and HDPE.
EVA copolymers are used in their pure form or mixed with other thermoplastic materials, for use in the manufacturing of industrial glues, among other things.
Certain additives, such as calcium fillers, organic or mineral pigments, antioxidants, surface modifiers (for smoothing the surface of resins and improving electrical conductivity), or pore-forming agents (to create alveolar material) are added to polyethylene before use.
Polypropylene (PP) on the other hand is a solid obtained through the polymerisation of propylene which offers good heat-resistance, only melting at 160 or 170°C.
It comes in the form of powder, fibres, or granules, and is used most notably for various filtering products, pumps, fenders, automobile reservoirs, or various packaging films. As a matter of fact, some of these products, after going through the plastic packaging recycling cycle, will be used to make wrapping for industrial liquids.
Additives used during its manufacturing are the same as for PE. The “injection” of PP creates plastics that are easily recycled, except for “film” PP.
It can be noted that thermoplastic elastomers can be obtained by combining EPDM rubber (ethylene propylene diene monomer) with polypropylene.
2/ VINYL POLYMERS
The vinyl polymer family contains a great number of thermoplastic materials, among which are:
- Polyvinyl chloride (PVC), that can come in many shapes, powdered, granules, a paste, an emulsion, or dissolved. Supple PVC can be used to make coated textiles for clothing and leather goods, insulation sheathing, adhesive tape, or tarpaulin (some of these will become recyclable products). The rigid PVC can be used for sanitation pipes, windows, blinds, gutters, electrical cables, surfacing, and food or chemical packaging (these are also future recyclable plastic material). When making this type of plastic, stabilisers, lubricants, plasticisers, fillers, and pigments can also be added. And although some PVC products, such as plumbing, can not be recycled, most can undergo the plastic recycling cycle (such construction waste).
- Polyvinyl alcohol (PVOH) comes in the form of a white water-soluble resin, and is particularly used as a binder coating for paper and cardboard, for industrial glues, or textile finishing.
- Polyvinyl acetate (PVAC), whose polymer is a transparent resin, is commercialised as granules, cartons, pearls, and various solutions. It is used mainly for paints, or quick-dry varnishes.
- Polyvinylidene chloride (PVDC) is a powder with strong chemical resistance and is highly impermeable to water vapour, certain gases and oils. Industries uses it to make certain complex paper-based materials (such aluminium foil) or plastic films.
- Polyvinyl butyral (PVB) or formal (PVF) comes in the form of powder, emulsions, or leaves, and, due to its strong adhesive power to metal, is used to make various varnishes for copper or aluminium wiring.
There are only two major types of polystyrenes: polystyrene (PS), and styrene copolymers (SAN, ABS, MBS, SBS, or SIS).
However, there different PS categories: standard PS, or ‘crystal’ due to its transparent aspect (it is particularly rigid and fragile), the suppler high-impact PS, heat resistant PS, and expanded PS (gas bubbles).
Solid up to 140°C after which it liquefies, PS can be delivered as powder, granules, pearls, paste, solution, or semi-finished products (sheets, tubes, planks…).
Chemical additives can also be used in its manufacturing, such various plasticisers or solvents, some fillers, and certain pigments. It is used for making yoghurt pots, food containers, bathroom cabinets, the inside of fridge and freezer doors.
A styrene copolymers is a chemically or physically improved polystyrene. It is used to make a many products, such as computer casings, coffee filters, jars, cosmetic packaging, vacuum cleaner cowlings, and even toothbrushes.
Some PS and ABS plastic waste are part of the list of recyclable plastics and are recycled by Paprec. PS waste can be recovered into plastic films, packaging, or insulation material.
4/ ACRYLATE AND METHACRYMATE POLYMERS
This type is divided into only two categories, poly(methyl methacrylate) (PMMA) and polyacrilonitrile (PAN).
PMMA is obtained by the polymerisation of methyl methacrylate, and is characterised by its transparency, the ease with which it can be used, and its resistance to time. Delivered as sheets, casts, bracers, disks, rods, powder, granules, or syrup, it is used to make synthetic fibres, lenses for glasses, windows, angle brackets, rulers, contact lenses, and various hair dressing items. It is one of the plastic industry’s recyclable materials.
PAN is particularly used as a synthetic fibre, as it is soluble in certain solvents, which allow it to be spun. But it is also used for certain food-grade films and jars. PAN is made using only few additives. PMMA on the other hand uses polymerising catalysers, colorants or pigments, plasticisers, silica fillers, or solvents.
Polyamide (PA) are alone in their category, but their names indicate the number of carbon atoms in their monomers (PA 6, PA 11, PA 12, etc).
Obtained from amino-acids or lactams, this very special material does not gradually soften under heat, like other thermoplastics, but goes very quickly from a solid to a gaseous state.
Though polyamides are mainly used to make textile fibres, they are also used in switch, electrical plugs, gears, screws, household appliances, syringes, or automobile parts, and can undergo the plastic recycling cycle.
Obtained from bisphenol A, polycarbonates (PC) is very rigid and hardly combustible, and is used in technical products. It comes in the shape of granules, sheets, leaves, or films, and is used to make CDs, motorcycle helmets, or security glass, and can undergo one of the recycling cycles.
Celluloid acetate (CA) is a transparent, supple, and stable material that allows industries to make fibres, varnishes, or photographic films, among other things.
Celluloid nitrate (CN) was used to make celluloid (now considered to unstable), and is now used to make various varnishes, paints, inks, glues, and certain artificial coatings.
8/ LINEAR POLYESTER
Polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytetramethylene terephthalate (PTMT), are three of the main linear polyesters, materials synthesized from ethylene glycol or butylene glycol.
With little additives, these were first used to make fabrics or films (such as terphane), until its resistance to abrasion, oils, saline solutions, and impact lead the plastic industry to use PET in the composition of ribbons, electronic components, and recyclable PET bottles, and to use PBTB in mechanical or insulations products that were submitted to high temperatures.
Recycling PET (and specifically PET bottles) is one of Paprec’s many activities in plastic waste recycling. Plastic bottles are recycled into sleeping bags, fabrics for the car industry, and, of course, new bottles.
There 3 types of polyfluorethanes: polytetrafluorethylene (PTFE), polychlorotrifluorethylene (PCTFE), and polyvinyl fluoride (PVDF).
PTFE comes in a granulated powder form. It has good heat-resistance despite the fact that it is not really a thermoplastic (when heated to a certain temperature, its irreversibly turns into a gel), and is known for absorbing very little water, anti-adhesive properties, high flexibility, and a good resistance to light and bad weather.
It is used to make no-stick coating, pipes, bearings, pads, seals, and technical textile.
PCTFE comes in two forms: high-polymer plastics (granules or powder), and low-polymer liquids. PVDF is a very recent discovery, still in development stages. Both of them chemically and thermally more stable than PTFE, and are used to make certain artificial coatings.
Polyoxymethylene (POM) and its similar copolymers are the only polyacetals.
Rigid, very resistant, especially to organic solvents and strong charges, a good electric conductor, POM comes in the form of moulding powder, granules, and semi-finished products (rods, sticks, tubes, etc). It is used to make gears, screws, small connecting rods, sliding parts, piping, or portable tools.
Polysulfones, trademarked under such names as Sulfover or Surfil, are macromolecules containing sulphur dioxide. They are used in paints and varnishes and have a good resistance to chemical acids and bases, oils, and fats.
12/ POLYPHENYLENE SULFIDE
PPS is a dark and stiff polysulfide. It has good heat and chemical resistance. It is used to make non-corroding parts, cooking utensils, or non-stick coating.
13/ MODIFIED POLYPHENYLENE OXIDE (PPO)
Modified PPO is difficult to transform. It must be altered and mixed with polystyrene before it can be industrialised, hence its name.
Thermosetting plastic is a compound that, during condensation polymerisation (and/or implementation), when submitted to a catalyst or a temperature increase, irreversibly cures. the structure, shape, or rigidity of the manufactured plastic object can not be modified again, and the material is rarely recycled.
This type of plastic includes the following types of compounds:
1/ UNSATURATED POLYSTER
Unsaturated polyesters are reticulum polymers made from dibasic organic acids (capable of giving off protons with 2 acid functions). The resin is used to make varnishes, moulded objects, glues, and various binding agents.
2/ PHENOL FORMALDEHYDE RESINS
Obtained by condensation polymerisation of phenol and formaldehyde, they are usually abbreviated to PF. It comes in the form of powder, granules, liquid, and solid or liquid resin. With certain additives, they are used to make some printing inks, foams, abrasive materials, parts for brakes or clutches, and various paints.
3/ MELAMINE RESINS
Melamine, such as Urea-Formaldehyde (UF) or Melamine Formaldehyde (MF), are obtained through condensation polymerisation of formaldehyde and urea or melamine. UF is used as an adhesive in the wood industry, and MF is known mainly under the trade name Formica.
After the condensation polymerisation of epichlorohydrin with poly-alcohol or phenol (such as bisphenol A), polyepoxides, or epoxy resins, are used in various forms (self-setting resins, powders, glues, etc) to cover surfaces, for adhesives, and for various paints, allowing them good resistance to metals.
Polyimides (PI) are made from the reaction of a diamine and a dianhydride, and are among the more recently synthesized plastics. They have very high heat-resistance, as well as good resistance to radiation and chemicals. They are mainly used in the form of films, as well as making supple circuit boards or wiring for electronics.
These complex compounds are made from polyols, chemical catalysts, polyisocyanates or expanding agents. Polyurethane (PUR) are used in the manufacturing of many products (foams, paints, condoms, varnishes, glues, and many types of solutions).
The textile industry uses it in an elastomer form to make Lycra.
Obtained through the condensation polymerisation of silanol and certain chemical additives, this type of plastic is more widely known as silicon, are very thermally stable (i.e. heat-resistant) and are used in the manufacturing of many products (oils, grease, cosmetics, hair products, pipes, moulded objects, etc).
The plastic recycling cycle is a step-by-step process. Discover the different steps :
Ask our Experts
In order for us to provide you with the most complete answer to your questions, please fill in all parts of the form below.
* Required field
In compliance with the stipulations of the Law of January 6, 1978, referred to as the "Law on Information Technology and Civil Liberties," you have the right at any time to access, modify, correct and delete your personal data. This right may be exercised by contacting us at the following address: Paprec Group, Département Communication, 7 rue Pascal 93126 La Courneuve Cedex - France