In modern materials science and industrial applications, mylar sheet, as a widely used material, plays a pivotal role. So, what exactly is mylar sheet? What are its characteristics? And in what fields is it used? This article will introduce this in detail.
What Is a Mylar Sheet?
Mylar sheet, also known as PET film, is athermoplastic polymer material, mainly composed of polyethylene terephthalate (PET), processed through a specific process. It is usually made by squeezing a thick plate and then stretching it in both directions (or one way) to obtain the required physical and chemical properties.
Mylar sheet has excellent mechanical properties such as high strength, hardness and toughness, as well as good optical properties such as high transparency, glossiness and low fog. In addition, it has excellent chemical stability, oil resistance, corrosion resistance and excellent electrical insulation. These characteristics make Mylar sheet widely used in packaging, printing, electronics, architecture,automobiles and other fields.
How Is Mylar sheet produced?
The production process of Mylar sheet mainly includes raw material preparation, extrusion casting, biaxially stretching, heat setting and winding.
- Raw material preparation: High-quality polyester chips (PET chips) are used as raw materials, and they are dried to remove moisture and ensure the purity of raw materials.
- Extrusion casting: The dried polyester slices are heated and melted, extruded into thick sheets through an extruder, and cooled and formed into a preliminary film through a casting roller.
- Biaxial stretching: The film after casting is stretched in both the longitudinal and transverse directions by a biaxial stretching machine to rearrange the molecular chains of the film and improve the mechanical strength and dimensional stability of the film.
- Heat setting: The stretched film is subjected to heat setting treatment to further stabilize the molecular chains of the film and improve the thermal stability of the film.
- Winding: The heat-set film is rolled up to form a rolled polyester film sheet for subsequent processing and use.
How Is Mylar Different from Regular Polyester Film?
Mylar, full name polyethylene terephthalate film (PET Film), is a polymer plastic film. So, what are the main differences between Mylar and Regular Polyester Film? In this section, LS uses a table to show the main differences between Mylar and Regular Polyester Film:
| Attribute | Mylar | Regular Polyester Film |
|---|---|---|
| Production process | Extrusion is made into thick sheets, which are then stretched in both directions | It may be a simple extrusion process that is not stretched |
| Transparency | High transparency, suitable for displaying packaging | Transparency can be relatively low |
| Strength and rigidity | High strength, high rigidity, suitable for load-bearing occasions | Strength and rigidity can be relatively weak |
| Dimensional stability | Excellent dimensional stability, not easy to deform | Dimensional stability may be poor |
| Heat tolerance | It has good heat resistance and can remain stable at higher temperatures | Heat resistance may be relatively poor |
| Electrical insulation | It has good electrical insulation | Electrical insulation may be average |
| Chemical resistance | It is chemically resistant and can resist a wide range of chemicals | Chemical resistance may be weak |
| Airtightness | It has good air tightness and is suitable for occasions that need to be sealed | Airtightness may be average |
| Fields of application | It is widely used in packaging, printing, electronics, electrical insulation and other fields | The field of application may be relatively limited, mainly in applications where materia l properties are not required |
Which Industries Rely on Mylar Sheet?
Mylar Sheet is a high-performance polymer material that is widely used in many industries due to its good heat resistance, cold resistance, chemical corrosion resistance and electrical insulation. The following are some industries that mainly rely on mylar Sheet:
- Packaging industry: Mylar Sheet has excellent barrier properties and water resistance. It can be made into various packaging bags, packaging boxes, etc., which are used for packaging of food, medicine, cosmetics and other items to ensure the freshness and safety of the products.
- Electronics industry: Mylar Sheet has good insulation and heat resistance, and is an ideal insulation material and protective film for electronic components. It is widely used in the manufacture of electronic products such as capacitors, motors, and transformers.
- Construction industry: Mylar Sheet has good weather resistance and chemical corrosion resistance, and can be made into various building films, such as roof waterproofing film, wall protection film, etc., to improve the service life and aesthetics of buildings.
- Optical industry: Mylar Sheet has high transparency and good optical properties, and is an important material for making optical products such as optical lenses and screen protectors.
- Automobile industry: Mylar Sheet is also widely used in the automobile industry, such as heat insulation film for car windows, car body film, etc., to improve the comfort and aesthetics of cars.
- New energy industry: With the rapid development of the new energy industry, the application of mylar Sheet in solar panels, lithium batteries and other fields has gradually increased, and it is used to make battery separators, packaging films and other materials.
What are the types of mylar?
1.Type of Material
- Basic Mylar (pure PET):Terephthalic acid (PTA) is polymerized with ethylene glycol (EG) without any comonomer. High transparency (>90%), rigidity and resistance to chemical corrosion.
- Co Modified Mylar：
PETG (ethylene glycol+CHDM): Low glass transition temperature (~50 ° C), good flexibility, good impact resistance.
APET: High temperature resistance (melting point>300 ° C), excellent dimensional stability.
- Functional Mylar：Special functions by coating, composites or nanomodifications
Conductive type: Copper /aluminum layer plating (for electromagnetic shielding).
Barrier type: Multi layer co extrusion (e.g. PET/PA/PE) enhances oxygen/water vapor barrier properties.
Antistatic type: coated with carbon powder or conductive polymer.
2.Processing technology
- Uniaxial stretch film:Stretching only in one direction results in poor thickness uniformity and is mainly used for coil materials.
- Biaxial stretch film:Stretching in both longitudinal and transverse directions, with balanced mechanical properties and higher transparency.
- Multi-layer composite film:Composite multi-layer structures(such as PET/TPU/PET) through co extrusion or coating processes to enhance overall performance.
- Microporous membrane:Micro scale pores are formed through laser drilling or chemical etching for filtering or breathable materials.
3.Thickness and specifications
| Thickness range | Typical use | Processing method |
| Ultra thin (<10 μ m) | Flexible display screen, electronic tag. | Biaxial stretching, microporous forming. |
| Conventional type (10-50 μ m) | Packaging film, insulation layer. | Packaging film, insulation layer. |
| Thick type (>50 μ m) | Industrial buffer pads, building film materials. | Uniaxial stretching, hot pressing composite. |
4.By Environmental Attributes
- Fossil based Mylar: A traditional PET material that relies on petrochemical resources is non-degradable.
- Biobased Mylar: PLA/PHA blend film,partially biodegradable(6-18 months under compost conditions). Recycled PET (rPET) is made by recycling plastic bottles and can reduce carbon emissions by more than 30%.
How to Choose Mylar Thickness for Specific Needs?
When choosing the thickness of mylar, comprehensive consideration should be given according to specific needs. The following is a specific method for selecting the thickness of mylar according to different needs:
1. Clarify the usage scenario
Packaging field:
- Food packaging: For small packages such as candy and chocolate that need to show the appearance of the product, thinner mylar, such as 25 microns or less, can be selected. For foods that need to be stored for a long time or moisture-proof, such as meat and dairy products, thicker films, such as 50 microns or more, should be selected to provide better barrier properties and mechanical strength.
- Pharmaceutical packaging: Pharmaceutical packaging has high requirements for barrier properties and hygiene, and usually medium-thick mylar, such as 30 to 50 microns, are selected to ensure the safety and stability of the drugs.
Electrical insulation field:
- Wire and cable insulation: Common thickness is 25 to 75 microns, depending on the voltage level and insulation requirements.
- Capacitor dielectric: Common thickness is 3.5 to 12 microns, requiring the film to have a high dielectric constant and low loss factor.
2.Evaluate performance requirements:
Based on application requirements, evaluate the required mechanical strength (such as tensile strength, tear strength), barrier properties (such as gas, water vapor barrier), transparency, heat resistance, chemical stability, etc.
3.Consider product characteristics:
Analyze the characteristics of the packaged or protected product, such as weight, shape, shelf life requirements, storage conditions, etc. These factors will affect the choice of film thickness.
4.Reference to industry standards:
Consult relevant industry standards or specifications to understand the specific requirements or recommendations for polyester film thickness for specific applications.
5.Cost-benefit analysis:
On the premise of meeting performance requirements, consider the impact of film thickness on cost and choose the most cost-effective thickness.
6.Consult professional advice:
If necessary, consult polyester film suppliers or industry experts for more professional advice and guidance.
Conclusion
As a high-performance, multi-purpose mylar plastic film material, mylar sheet plays a vital role in modern industry and daily life. By deeply understanding the definition, characteristics, production process, main types, application fields, market status and development trends of polyester film, we can better use this material to bring more convenience and benefits to our life and work. In the future, with the continuous advancement of science and technology and the continuous development of the market, the application prospects of polyester film will be broader.
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The content appearing on this webpage is for informational purposes only. LS makes no representation or warranty of any kind, be it expressed or implied, as to the accuracy, completeness, or validity of the information. Any performance parameters, geometric tolerances, specific design features, quality and types of materials, or processes should not be inferred to represent what will be delivered by third-party suppliers or manufacturers through LS’s network. Buyers seeking quotes for parts are responsible for defining the specific requirements for those parts. Please contact to our for more information.
Team LS
This article was written by various LS contributors. LS is a leading resource on manufacturing with CNC machining, sheet metal fabrication, 3D printing, injection molding,metal stamping and more.
FAQs
What does mylar mean?
Polyester film is a transparent or colored film made of polyester resin through extrusion, stretching, and other processes. It has excellent physical properties, chemical stability and processing properties, and is widely used in packaging, electronics, construction, optics, medical and other fields.
What is a polyester film sheet used for?
Polyester film sheets are used for a variety of purposes. It can be used for packaging materials, such as food packaging, pharmaceutical packaging, etc.; In the field of electronics, it can be used as an insulating material, protective film, etc.; In the field of construction, it can be used for heat insulation and sound insulation materials; In the field of optics, optical lenses, reflective films, etc. can be made; In the medical field, it can be used for the packaging and disinfection of medical devices. In addition, polyester film sheets can also be used to make labels, nameplates, billboards, decorative paintings, etc.
What is the purpose of polyester film?
The main purpose of polyester film is to provide a film material with excellent physical properties, chemical stability and processing properties to meet the demand for film materials in different fields. It can protect the product, improve the added value of the product, prolong the service life of the product, and at the same time, it can also give the product more function and aesthetics through printing, coating and other processing methods.
What type of paper is mylar?
Mylar is not paper, but a plastic film. It is very different from traditional paper in terms of material, performance and application. With higher strength, heat resistance, barrier and processability, polyester film can be applied to more fields and meet more needs. Therefore, it is inaccurate to refer to mylar as “paper”.
