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Views: 18 Author: Site Editor Publish Time: 2023-03-23 Origin: Site
Plastic sheets have seen immense growth in applications across many industries over the past few decades. This can be attributed to their beneficial properties including light weight, durability, corrosion resistance, flexibility and ease of fabrication. When compared with traditional materials like wood, steel and glass - plastics provide better strength to weight ratio, resistance to weathering, and lower long term costs.
The global plastic sheet market size is valued at over USD 100 billion in 2022. Major end use sectors driving the demand include packaging, construction, automotive, industrial machinery, consumer goods and electronics. Within this landscape, two commodity thermoplastics - polyethylene terephthalate (PET) and polyvinyl chloride (PVC) account for a major share of the plastic sheets market.
PET and PVC resins are widely produced globally due to their versatility and performance advantages over other polymers. PET provides high strength, transparency and chemical resistance whereas PVC exhibits heat resistance, flexibility, low smoke emission properties and affordability. Manufacturers leverage these unique attributes to create varied product formulations suitable for specific applications.
Both amorphous and crystalline grades of PET and PVC are processed using extrusion, casting, lamination and thermoforming techniques to form plastic sheets in varied thicknesses from 0.5mm to over 5mm. Post formation finishing steps involve printing, coating, surface treatment etc. The finished plastic sheets compete against traditional materials, offering design flexibility and helping reduce product costs.
In this detailed article, we analyze and compare the key physical, mechanical and chemical properties of PET Plastic Sheet and PVC Plastic Sheet. We discuss the standardized test methods to characterize these properties and understanding their influence on applications. The major global end uses where each polymer type excels are also explored in depth.
Tough and Impact Resistant
PET sheets demonstrate high tensile strength of over 70 MPa, imparting robustness and resistance to impact loads without breakage. This is due to the crystalline molecular structure of PET resins providing rigidity and toughness even at low thicknesses. Standard tests like falling dart impact or bending under load show PET withstanding 5000g forces at room temperature.
Dimensionally Stable
PET maintains dimensions within a tight tolerance band of 0.05-0.2% even if exposed to temperature swings between -30°C to 85°C. This is attributed to its high glass transition temperature of 75°C above which it retains amorphous phase without changes. Low water absorption below 0.15% by weight over prolonged immersion periods ensures no plasticization effect on properties.
Clear and Glossy
Virgin PET polymers processed under controlled conditions yield an amorphous transparency where packaging contents can be clearly seen. The density allows reflecting light for a glossy mirror-like finish appealing for aesthetics and branding applications. Haze values are below 1% enabling excellent visual clarity.
Heat Resistant
PET withstands heat relatively well with a heat deflection temperature under load (HDT-A) of around 80°C allowing use in hot filled containers and under hood car components near engines. Above the glass transition, it does not degrade or lose mechanical integrity on short term intermittent high temperature exposures.
Chemical Resistant
PET structure provides resistance to a broad range of chemicals - acids and alkalis with pH of 3-9 do not affect it. It is also unaffected by alcohol, oils and resist discoloration when in contact with foods and drinks. Only strong oxidizing acids or ketones can potentially degrade PET over long periods.
PET Plastic Sheet
Food packaging
Clear PET films are widely used for packaging snacks, chips, biscuits and other foods due to their transparency, barrier properties, and recyclability. PET provides an excellent barrier against moisture, gases, and odor which helps protect the food and extend its shelf life. It is lightweight and durable making it suitable for packaging a variety of snacks and foods.
Bottles
The majority of water bottles, soda bottles, and beverage containers are made from PET plastic. It is favored for bottles due to its shatter resistance, clarity, and flexibility. PET bottles maintain their shape and are less likely to break if dropped compared to glass. The material is inexpensive and recycled PET can be used as a raw material input which makes it economically viable for water and beverage companies.
Construction sheeting
In the construction industry, PET roofing and wall cladding sheets are used due to their weather resistance, durability, and lightweight properties. The material does not deteriorate when exposed to sunlight and withstands other environmental conditions like rain, wind, etc. making it suitable for outdoor construction applications. It is cost effective and easier to install than traditional construction materials like metal or wood.
Signs and graphics
Clear and colored PET sheets are commonly used as the base material for outdoor signs, posters, vehicle graphics, and other signage applications. The material has excellent printability and withstands the effects of weather, temperature extremes, and moisture without fading or deteriorating over time. It provides a durable, transparent substrate for easy viewing of graphics and sign content from a distance.
Solar panels
In photovoltaic solar panels, PET films are used as back sheets or cover sheets placed on the back or top of the solar module. The UV-resistant and weatherable properties of PET protect the internal solar cell components from damage caused by sunlight over the long operational life of up to 25 years for solar installations. Its transparency also allows sunlight to pass through to the solar cells when used as a top sheet cover.
Automotive glazing
PET plastic sheets are sometimes used to replace glass in certain vehicle windows, door windows, sunroofs, and other automotive glazing applications. They provide shatter resistance for safety in case of accidents. Being much lighter than glass also improves fuel efficiency. Modern automotive grades of PET have high optical clarity like glass as well.
Economical
PVC resin is inexpensive to produce compared to other plastics like PET. Being a commodity plastic, PVC sheets offer excellent value for money. The cost savings make it suitable for mass production of consumer goods and bulk materials like pipes, wires, flooring, etc.
Weather Resistance
Rigid PVC formulations contain UV stabilizers that allow the material to withstand up to 5 years of direct outdoor exposure without significant degradation. The chlorine content provides resistance against heat, sunlight, moisture, microbial attack etc. maintaining physical properties.
Flexibility
Soft/flexible grades of PVC contain large amounts of plasticizers that impart flexibility even at room temperature. These can be easily formed, wrapped, installed without heating. Specialty flexible PVC films can wrap complex contoured surfaces while holding the given shape.
Decorative Finishes
PVC accepts lamination with papers/films, thermoforming of textures and grain patterns, spraying of paints etc. Aesthetic surfaces mimic other materials at lower cost. Digital/screen printing on PVC enables graphics/advertisements on signs with longevity and low maintenance.
Water Resistance
PVC has a service temperature limit above water's boiling point. With only 0.1% moisture absorption even after immersion, PVC sheets retain properties to function in damp/humid environments including pipes, flooring, cable insulation without deterioration.
Low Combustibility
The chlorine content (around 56-57% by mass) allows PVC to behave as an intumescent material when exposed to fire - expanding into a thick insulating char without melting or flowing. PVC has a UL94 V-0 or 5VA flame spread rating.
PVC Plastic Sheet
Signage Boards and Displays
PVC sheets are widely used for making sign boards and display graphics due to their durability and weather resistance. Signs made with PVC can withstand prolonged outdoor exposure without degradation. PVC accepts direct printing and painting very well, allowing vibrant graphics and colors. It is also cost-effective compared to other materials like aluminum composites. Common applications include shop signs, billboards, advertisement kiosks, exhibition displays, and POP/GEL displays.
Flooring
PVC flooring is very popular due to its affordability, durability, and ease of cleaning and maintenance. DifferentFlooring styles suited for various spaces are available - from solid rigid sheets to flexible vinyl tiles and planks. PVC floors are waterproof, chemical resistant and have anti-static properties, making them suitable for use in kitchens, bathrooms, hospitals, schools, malls, offices etc. They can resemble wood, tiles or stone at a fraction of the cost.
Furniture
PVC sheets are used extensively in the furniture industry. Laminated or coated PVC sheets are commonly used to make furniture parts, cabinets, store fixtures, tabletops etc. that need to withstand wear and moisture exposure. These coated sheets mimic the looks of wood while providing resistance to stains, scratches, cracking and fading. Curved and contoured sections can also be readily fabricated using soft PVC sheets.
Automotive and Construction
Automotive window and door profiles, dashboards, molded interior panels use rigid PVC sheets for their structural rigidity and weather resistance. In construction, PVC forms roofing sheets, siding, piping, ducting, fencing etc. PVC siding sheets come with wood grain finish and rarely require painting as they resist rot, cracking and peeling for decades. Due to foldability, reinforced PVC membranes are used for tunneling and excavation works.
Packaging
PVC films are excellent moisture and vapor barriers, forming lids, blister packs for products. Being inexpensive and printable, PVC sheets package electrical goods, small appliances, toys, accessories etc. Rigid sheets make panels, backsheets for electronics. Medical devices like blood bags, tubing use plasticized PVC sheets that do not interact with fluids. PVC resins add value with colorability and processability.
Electrical
Exploiting its insulation properties, PVC sheets insulate power cables, wire & cable sheathing, switchboards, plugs, sockets, junction boxes etc. preventing electric shocks. Conduit pipes route cables concealed in buildings. PVC insulated tools provide protection to users. In solar energy also, PVC acts as protectant in flexo cables that link panels to inverters. Custom-molded grade brings reliability as electrical insulator.
The table below summarizes the comparison between key properties and applications of PET and PVC plastic sheets:
| Parameter | PET sheet | PVC sheet |
|---|---|---|
| Tensile strength | High | Moderate |
| Impact resistance | High | Moderate-High |
| Clarity | Clear and glossy | Can be clear but often opaque |
| Heat deflection | High (70°C) | Moderate (50-60°C) |
| Chemical resistance | Very high | Good but weaker than PET |
| Fabrication | Brittle, not formable | Soft grades are formable |
| Recyclability | Highly recyclable | Requires special treatment |
| Weather resistance | Very high | High |
| Cost | Moderately high | Low |
| Fire resistance | Burns easily | Self-extinguishing |
| Flexible grades | Not Available | Soft PVC available |
| Common uses | Packaging, bottles, displays | Signage, flooring, cables |
In summary, PET and PVC plastic sheets both have their relative advantages and disadvantages when considered for different application requirements. While PET provides superior mechanical strength, transparency, and resistance to chemicals, it is generally a more expensive material. The cost-effectiveness of PVC makes it attractive for bulk-volume applications.
PET sheets deliver higher tensile strength, impact resistance, and dimensional stability compared to basic PVC formulations. This allows PET to compete in high-performance applications such as beverage bottles, construction sheeting, and automotive glazing where durability is critical. However, specialty PVC grades with reinforcing fillers and impact modifiers have been developed to bridge the performance gap.
In terms of aesthetics, virgin PET resin provides optically clear glossy surfaces ideal for packaging and displays. PVC can also be made transparent but often contains whitening additives and is not as glossy as PET. However, PVC's capability for surface decoration through printing and coatings offers versatility in visual appearance.
Over the long term, PET maintains its mechanical integrity when exposed to chemicals, heat and environmental stresses better than standard PVC. This suitability for continuous harsh chemical contact gives PET an edge in industrial process equipment and piping. Nevertheless, formulating PVC with expensive stabilization packages extends its durability for withstanding weathering.
As far as overall costs are concerned, bulk volume applications favor PVC due to its cheaper price point versus PET. This cost advantage helps PVC capture sizable shares in flooring, plumbing, wire insulation and signage markets.
In conclusion, both plastics are here to stay due to their differentiated properties serving unique purposes across manufacturing industries globally. Superior performance or economics becomes the deciding factor on a case-to-case basis between PET and PVC materials.
