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Extrusion machine: light transmission, properties and applications of transparent polymers

June 13,2023

From milk bottles, to optical lenses, to TVs or cell phones …… the list of applications for transparent plastics is never ending. Today, we are surrounded by many types of transparent or transparently modified plastic materials that make products more attractive and portable than traditional glass.
Now, several manufacturers are taking advantage of the quality and color consistency of transparent plastic materials for a variety of applications :
1. manufacture lightweight, durable and shatterproof products;
2. Reduction of production costs;
3. production of complex geometries and uniquely shaped components;
4. Achieves visible transmittance and/or optical refractive index comparable to that of glass
And so on…

Some popular application areas that benefit from the above advantages are:

1. Packaging (food, cosmetics ……)
2. Consumer products (food cans, data storage products, lenses ……)
3. Architectural glass (aquariums, safety enclosures ……)
4. Automotive and electrical components (LED, headlight covers ……)
5. Healthcare (syringes ……)
6. Agricultural film
It is worth noting, however, that despite the wide range of applications, only a few polymers meet such demanding material specifications.
Let’s take a look at this “shiny” category of plastics and take stock of the properties and popular applications of some transparent polymers (PC, PMMA, PET, SMMA, COC, etc.)!
Due to the limited space, PS/SBC/ASA/MBS/PCTA+PCTG/PMP (polymethylpentene) and other new transparent polymers in this article will not be repeated.

Polycarbonate (PC)
Polycarbonate (PC)is a high-performance tough, amorphous and transparent thermoplastic polymer with a unique combination of high impact strength, dimensional stability, and good mechanical properties. It transmits more than 90% of light and blocks UV radiation, and provides 100% protection from the sun’s harmful UV rays.

Polycarbonate sheet/pipe extruder machineis used in a variety of everyday applications:
Electrical and electronic products (LED lights, connectors, cell phones ……)
Automotive (headlight bezels, door handles, radiator grilles and inner lenses)
Agriculture (greenhouse cover materials)
Consumer products (glasses, appliances, food contact ……)
Medical (surgical instruments, equipment ……)
Clear sheets made from PC are 200 times stronger than the same thickness of glass in impact tests and are easy to cut.
Transparent nylon (PA TR)
By changing the type of diamine, diacid or amino acid, nylon varieties with different physicochemical properties can be obtained, including general-purpose nylon, long carbon chain nylon, high temperature resistant nylon, transparent nylon and nylon elastomer. Transparent nylon is an amorphous or microcrystalline thermoplastic nylon with light transmittance up to 90%, close to PMMA.
Because transparent nylon has better resistance to oil, corrosion, abrasion and scratch than other transparent plastics, it is widely used in automotive, electrical and electronic, mechanical, optical, sports and other fields.
Acrylic PMMA
PMMA is a rigid, transparent thermoplastic material that is widely used as a “shatterproof” alternative to glass. This polymer offers several technical advantages over other transparent plastics (PC, PS), such as:

High UV and weather resistance.
With up to 92% light transmission and optical properties, the unlimited coloring options.
These advantages make PMMA sheet Extruder suitable for architecture and construction to build greenhouses, marine centers; car windows, lamp shades, lights, electronic equipment displays, designer furniture, etc.
Polyethylene terephthalate (PET)
PET is a versatile transparent thermoplastic polymer that is characterized by its excellent combination of mechanical, thermal, chemical and dimensional stability properties PET may appear opaque, white and transparent, depending on its crystalline and amorphous structure.
PET’s desirable (transparency, light weight, high strength, stiffness, high chemical resistance, barrier properties and low price) make it the material of choice for:
Water bottle
Carbonated soft drink containers
Motion picture film

PET is preferred over polycarbonate (PC) due to lower cost, better aesthetics and better handling.
Amorphous copolyester (PETG)
Amorphous copolyesters such as PETG are versatile and can be used for a wide range of applications. Amorphous copolyesters combine excellent clarity and toughness with outstanding heat and chemical resistance.
PETG can be used as a direct replacement for PC, PMMA and PC/polyester with minor or no modifications.

Polyvinyl chloride (PVC)
PVC is an amorphous thermoplastic with excellent transparency. Clear PVC sheets combine excellent mechanical properties and impact strength with water-clear transparency and outstanding chemical and fire resistance.
Also, clear PVC pipes are specially formulated to block harmful UV rays. These pipes are widely recommended for outdoor applications that are exposed to sunlight and require transparency.

The optical properties of transparent PVC products range from high light transmission to high transparency and anti-glare surfaces to high impact strength, making them suitable for external applications. Key applications for clear PVC sheets, pipes and transparent films extrusion line include:
Architecture – light, safety glass, greenhouse ……
Packaging – blister packaging, cling film, transparent packaging ……
Medical – bags, tubing, drippers, connectors, valves ……
Liquid Silicone Rubber (LSR)
Liquid silicone rubber is a low-viscosity, transparent thermosetting elastomer compound with:
Excellent optical clarity (94% transmittance)
Durability (high temperature resistance up to 150°C)
Excellent processability
Design Freedom

It is a lightweight material that has successfully replaced glass and other thermoplastics in a variety of applications such as high power LED lighting, electronics, automotive lighting, consumer products, healthcare, etc. where high transparency, heat/UV resistance and long-term durability are key requirements.
Cyclic Olefin Copolymer (COC)
Cyclic Olefin Copolymer (COC) is an amorphous, transparent thermoplastic produced by chain copolymerization of cyclic monomers with ethane. It is a relatively new class of polymers compared to commodities such as polypropylene and polyethylene, and is known for its excellent optical clarity, good mechanical properties, and moisture resistance.

COC’s excellent optical properties make it ideal for food packaging films, optical data discs, high-precision lenses, optical films, and more. In addition, cyclic olefin copolymers are resistant to moisture, solvents, and sterilization, making them useful in medical and life science applications such as blister packaging, medical trays, and more.
Polyethylene (PE)
Polyethylene is a very durable thermoplastic that is widely used in several markets (packaging, automotive, electrical, etc.) to produce films, tubing, plastic parts, laminates, and more. It is the most produced plastic in the world and you use it almost every day.

LDPE plastic production line: LDPE is flexible, tough and transparent, and is widely used in plastic bags, transparent films, laboratory equipment and other fields.

Transparent polypropylene (PP)
Polypropylene is an excellent resin with good physical properties, cost effectiveness and recyclability, but due to its crystalline nature, it is difficult to obtain transparent PP sheets. Today, however, thanks to new highly effective clarifying additives (also known as clarifiers), significant advances have been made in transparent polypropylene (PP) as these polymers offer design flexibility, easier processing capabilities, better colorability/decorative properties, and cost savings through light weighting.

In addition, a combination of rapid quenching and proper heat treatment can improve the transparency of polypropylene extruded sheets. Other advantages that make clear PP a viable alternative to more costly transparent materials such as glass and transparent plastics (PS, PC, PETG) include:
Good stiffness/impact balance;
Good moisture/moisture barrier
Fluorinated Ethylene Propylene (FEP)
Fluorinated ethylene propylene (FEP) is chemically a copolymer of hexafluoropropylene and tetrafluoroethylene. This polymer transmits a high percentage of ultraviolet and visible light. FEP in film form has a daylight transmittance of approximately 96%.FEP film transmits more ultraviolet, visible and infrared radiation than ordinary glass.
Styrene methyl methacrylate (SMMA)
SMMA or styrene methyl methacrylate (SMMA) is a highly transparent styrene-acrylic acid copolymer with an excellent glossy surface. It combines the excellent processing advantages and cost attractiveness of styrene polymers with high brightness and clarity.Other benefits of SMMA are:
Excellent thermal stability;
Better alcohol resistance than acrylic;
Mechanical properties superior to GPPS;
Scratch resistance;
FDA complaint.

Compared to PMMA, PC and PET, SMMA is cheaper and has similar surface quality.
SMMA is suitable for applications requiring strong, rigid, water-transparent properties, such as household products, glasses, glassware, cosmetic packaging, medical devices, personal hygiene products, etc.
Polystyrene(General Purpose – GPPS)
General purpose polystyrene (GPPS), also known as crystal clear polystyrene, is a transparent polymer with the following properties:
High stiffness;
Good dimensional stability;
Low specific gravity, and excellent heat resistance
Good electrical insulation properties

Due to its amorphous nature, it has advantages over other polymers in terms of transparency, low cost, and ease of processing. some applications for GPPS include toys, CD cases, coat hangers, refrigerator vegetable boxes, shower panels, IT equipment, clear jewelry boxes, refrigerator shelves and drawers, and plastic cups. It is also used in the manufacture of disposable medical products such as test tubes, test kit housings, diagnostic products, petri dishes, etc.
MABS (transparent ABS)
ABS is an impact-resistant engineering thermoplastic composed of three monomers: acrylonitrile, butadiene, and styrene. Styrene-acrylonitrile copolymers provide stiffness, while butadiene provides impact resistance.
The manufacturer adds methyl methacrylate monomer to the SAN phase to produce a highly transparent ABS resin called MABS (methyl methacrylate acrylonitrile butadiene styrene).MABS offers properties such as:

High light transmittance;
Low haze;
Consistent and stable color;
Improved flow characteristics.
Clear ABS has better impact resistance than polystyrene, SAN and PMMA, and offers good processability. MABS grades with improved flow characteristics can be used as an interesting alternative to polycarbonate (PC). Clear ABS is used in consumer appliances, medical applications, sporting goods, medical equipment, etc.

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