Plastic wrap is a form of food packaging consisting of a thin film of flexible, transparent polymer that clings to itself and to food containers to form a tight seal. The plastic keeps the food fresh by protecting it from air and by preventing dry foods from absorbing moisture and wet foods from losing moisture.

It also seals in odors to prevent them from spreading to other foods stored nearby. Plastics are artificial polymers; that is, they consist of gigantic molecules formed by combining thousands of small molecules of the same kind into a long chain. These small molecules are known as monomers, and the process of combining them is known as polymerization. Natural polymers include such familiar substances as silk, rubber, and cotton.

The first plastic was made by the British chemist Alexander Parkes inwho produced a substance he called Parkesine from cotton, nitric acid, sulfuric acid, castor oil, and camphor. Celluloid was a tremendous success and was used to make many different products, but it was highly flammable. The first completely artificial polymer unlike celluloid, which was a derivative of the natural polymer cellulose was Bakelite, which was produced from phenol and formaldehyde by the Belgian chemist Leo Baekeland in Many other polymers were developed during the 20th century, including such important products as artificial rubber and artificial fibers such as nylon.

The first plastic used for wrapping was cellophane, another derivative of cellulose invented by the Swiss chemist Jacques Brandenberger in It had the advantage of being transparent, and was used for packaging as early as Cellophane was the most common form of plastic film made untilwhen it was overtaken by polyethylene.

Polyethylene was discovered by accident by research workers at the British company Imperial Chemicals Industries inwhen they mixed benzene and ethylene at high temperature and pressure. Polyethylene was first used chiefly for electrical insulating material.

It was first made into a film in by the Visking Corporation in the United States, and has grown in popularity ever since. Polyvinyl chloride PVC was produced before World War II and was originally used as an inferior substitute for rubber, but films of this substance were not made in any quantity until the s. PVC is used today in many different products such as pipes, flooring, electric cables, shoes, and clothing, as well as plastic wrap.

It offered a high degree of protection from moisture and resistance to oils, greases, and corrosive chemicals, so it was used to package sensitive equipment such as optical devices and aircraft engine components.

In it was offered to the public under the familiar trade name Saran Wrap. These polymers are all derived from simple hydrocarbons such as methane or ethylene, which are produced from natural gas or petroleum. Polyethylene is made directly from ethylene. PVC is made from vinyl chloride, derived from ethylene, or from acetylene, derived from methane. PVDC is made from vinyl chloride and vinylidene chloride, a derivative of 1,1,2-trichloroethane, which in turn is derived from ethylene or acetylene.

Some plastic films, including cellophane, are derived from cellulose, which is obtained from wood pulp or from linters, tiny fibers that cling to cotton seeds after the longer cotton fibers have been removed by a cotton gin.

At least one form of plastic film Pliofilm, a trademark of Goodyear is derived from rubber. A variety of standard tests exist to ensure that plastic wrap is effective.

The most important are tests for permeability, impact resistance, and tear strength. Water vapor permeability is measured by filling a dish with calcium chloride, a highly water-absorbent substance. It is covered with a sample of plastic wrap and weighed.

The dish is then placed in a chamber with a controlled temperature and humidity. After a measured amount of time the dish is weighed again.Call Now - Shrink wrapping is an easy process requiring two basic elements: the right kind of shrink film and heat. With just a roll of shrink film and a heating source, you have all the tools you need to waterproof, weatherproof and tamperproof just about anything, regardless of size.

Given the flexibility, durability and other valuable advantages of using shrink film, many companies employ this option to package their products. Begin reading the full guide below, or fill out the form for a downloadable PDF version that you can reference later.

Shrink wrap, also referred to as shrink film or shrink wrap, is a versatile polymer material used for the packaging of finished goods. Heat is applied to the film — by either a conveyor heat tunnel or an electric or gas heat gun — which catalyzes the film to shrink tightly around the item placed within. This process results in a clear, durable barrier of protection around the product.

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So, how exactly does this happen? The science of shrink wrap can be explained in terms of molecular behavior. The molecules of a shrink film sheet or tube are randomly intertwined, meaning they are coiled and twisted with no particular alignment. When the film is warmed, the structureless regions of the chains are straightened and aligned to the direction of orientation. More simply, the molecules reorient from their initial random pattern to ultimately fit the mold of its contents.

Shrink wrap film is available in a variety of typesthicknesses, clarities, strengths and shrink ratios, which can be employed alone or in conjunction with one another to create the precise type of layering and protection for your product.

These options and constructions have broadened over time to accommodate specific requirements for sealability, optics, toughness, slip, temperature, force and memory.

Plastic Wrap

To protect and secure products for retail and shipping environments, there are three main types of films used in shrink wrapping : polyvinyl chloride, polyolefin and polyethylene. Each of these materials features different capabilities and characteristics that make them suitable for specific applications.

In addition, each one can be co-extruded into multilayer films with different additives in order to create distinct barrier properties that promote shelf life or a particular appearance.

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Shrink films can be formed into flattened rollstock, bags, overwrap, banding and tubing, and they can add a form of tamper-resistant protection to packaged goods. Given its lightweight nature, inexpensiveness and multi-purpose capabilities, PVC was once the most commonly used shrink packaging material in the world.

It has since given way to polyethylene PE and polyolefin POF for a number of reasons, including the health dangers posed during creation and incineration, as well as its level of sustainability.

In its rigid form, PVC is durable and used in such applications as construction projects and houseware products.Posted by Jerad Dowler on Thu, Mar 19, It has shown audiences that there is a lot that goes into making things that are easily taken for granted, and that is perhaps what makes the show so fascinating.

Knowing a little bit more about this product can actually help you get the most out of your stretch film at work. Whether it means changing the type or the approach that you use to wrap your productsa little knowledge of stretch film can go a long way. The first thing to know is that there are two ways to make stretch film.

Both processes create a film with distinct advantages and disadvantages.

stretch film manufacturing process pdf

There are also several traits that both types of film share, such as durability meaning they do not tear as easily as other types of wraps. Cast Stretch Wrap.

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As the name of the film suggests, the process to produce it is called the cast extrusion process. The first step requires the melting of thermoplastic material so that it can be squeezed through a flat die. From the flat die, the melted thermoplastic goes onto a chill roll where the film becomes solid, similar to the cooling of plastic.

This process makes it easier to see through the wrap, and when you unwind it from its roll, this film is much quieter than second type of film. If you do not want to use a machine as you package your goods, there are also hand grade casts films.

The process to produce this wrap is blown extrusion. Like the cast extrusion process, the thermoplastic material is melted, but it is then squeezed through a slit die that is annular and has a hole located in the center. It stands vertically so that the process creates a thin walled tube that inflates like a balloon when air is forced through the hole.

The process is more complex than the process used to make cast stretch wrap, which is why this wrap can be more expensive. Blown stretch wrap is more opaque because it tends to crystallize during the process. As a result you lose some of the visibility of your goods. It is also considerably louder as it is removed from the roll as it is securing your packages.

Plastic Wrap

Here at Paragon Films, all of our films are manufactured by the cast extrusion process. Many people ask, "What's better, Cast or Blown? Casting of film provides more uniform gauge, better cling, and greater percentages of stretch than blown film. Cast film is superior to blown film in tear strength in the machine or transverse direction, which aids in the prevention of tear propagation. Topics: stretch film productionCast extrusionHow it's madeBlown film. All rights reserved. Cast Stretch Wrap As the name of the film suggests, the process to produce it is called the cast extrusion process.

Blown Stretch Wrap The process to produce this wrap is blown extrusion.

Stretch Film Solutions

You have more questions?Stretch film is a plastic film used to secure, bundle, and stabilize products. Stretch film, made from linear low-density polyethylene.

When applying, the film is to be pulled and stretched around products to obtain tight and secured product loads. Stretch film comes in a variety of widths, thicknesses, and colors.

Choose everything from clear to colored and even anti-static stretch wrap film. The integrated handles are ideal for low volume output or mobile stretch wrap applications. Bundling film is a excellent alternative tape and plastic strapping for bundling multiple products together.

Vented stretch film is an 80 gauge stretch film with die-cut holes allowing products to breathe when palletized. Ideal for allowing firewood to cure and moisture to escape from fully loaded pallets. Companies use transparent stretch film to color code loads to make for easy identification during shipping. The opaque film conceals loads and protects shipments from UV light. True Gauged Stretch Film - For years, companies have used "true gauged stretcfilm," a product that offers an enormous amount of stretch, cling, and strength.

Over time this stretch wrap has become more expensive because it is thicker and uses more petroleum-based resins during the manufacturing process. This increase in price has encouraged manufacturers to find alternatives to keep costs lower. The term for alternative pallet wrap is "equivalent stretch film. Equivalent Stretch Film - An affordable alternative to "true gauged film. We offer two equivalent hand films that offer excellent hold, good stretch, and one-sided cling at an affordable price.

The primary difference between the two is the number of layers and the resin formulas. Hybrid rolls are thinner and made of more layers during the extrusion process. Micron rolls are in between the true gauged film and the hybrid stretch film thickness. It does not offer as many layers but does have more stretch than the hybrid film. It also provides better tear resistance. Thickness ga. The main goal of wrapping a full pallet load of products is to stabilize the products on the pallet to prevent product damage during transportation.

Pallets that differ in weight and height can change the amount of film needed. Another factor is the type of stretch film in use.

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Film type will directly determine the amount of film required as well as the amount of braking tension needed by the user. Begin bottom revolutions by wrapping the bottom of the boxes and the pallet while pulling the film to reach maximum stretch and hold tension.

Wrap multiple revolutions around the base of the pallet. The heavier the pallet, the more revolutions will be needed. After numerous revolutions are made around the bottom of the pallet slowly work up the pallet moving up half the film width each revolution. Once the top of the pallet is reached, wrap multiple revolutions around the top of the pallet for stabilization. For the video above, the user is wrapping a small inch high pallet weighing less than lbs.

The film used is 63 ga. See the step-by-step guide below. As stated above, the type of stretch film, the height of the pallet, and the weight of the pallet will all determine the number of revolutions needed to stabilize a pallet load correctly.

Stretch Wrap Information

For more information about stretch products and processes, visit our stretch wrap page or our page dedicated to stretch wrap film information.Stretch wrap or stretch film is a highly stretchable plastic film that is wrapped around items. The elastic recovery keeps the items tightly bound. In contrast, shrink wrap is applied loosely around an item and shrinks tightly with heat.

It is frequently used to unitize pallet loads but also may be used for bundling smaller items. Types of stretch film include bundling stretch film, hand stretch film, extended core stretch film, machine stretch film and static dissipative film. The most common stretch wrap material linear low-density polyethylene or LLDPE, which is produced by copolymerization of ethylene with alpha-olefin s, the most common of which are butenehexene and octene.

The use of higher alpha-olefins hexene or octene gives rise to enhanced stretch film characteristics, particularly in respect of elongation at break and puncture resistance. Other types of polyethylene and PVC can also be used. Once stretched, the elastic recovery is used to keep the load tight.

There are two methods of producing stretch wrap. This is a slower process but provides for higher quality in all the areas listed below. The cost of production is also higher due to the quantity that can be produced per hour. This makes the cooling process quick. The quality is not as good as blown but more can be produced in an hour with lower costs.

Other properties such as break strength, cling, clarity, tear resistance, static dischargeetc. In pallet unitizing, stretch wrap can have several functions:.

stretch film manufacturing process pdf

Making sure boxes stay on the pallet and properly aligned is an important consideration in warehouse distribution, especially as the demands for increased throughput continues to rise. Automatic wrappers are generally a variant of a semi-automatic system. Automatic wrappers include a conveyor system to automatically load the wrapping machine and automatic systems to apply, seal, and cut the film. From Wikipedia, the free encyclopedia.

Journal of Food Science and Technology. Barcode printer Barcode reader Bottling line Calender Can seamer Cartoning machine Case sealer Check weigher Conveyor system Extended core stretch wrapper Filler Heat gun Heat sealer Industrial robot Injection molding machine Label printer applicator Lineshaft roller conveyor Logistics automation Material-handling equipment Mechanical brake stretch wrapper Multihead weigher Orbital stretch wrapper Packaging machinery Palletizer Rotary wheel blow molding systems Shrink tunnel Staple gun Tape dispenser Turntable stretch wrapper Vertical form fill sealing machine.

1000mm double layer stretch film making machine

Biodegradation Environmental engineering Glass recycling Industrial ecology Life-cycle assessment Litter Packaging waste Paper recycling Plastic recycling Recycling Reusable packaging Reverse logistics Source reduction Sustainable packaging Waste management. Category: Packaging. Categories : Packaging Plastics applications. Hidden categories: Commons category link is on Wikidata. Namespaces Article Talk.

Views Read Edit View history. In other projects Wikimedia Commons. By using this site, you agree to the Terms of Use and Privacy Policy. Wikimedia Commons has media related to Stretch wrap.JavaScript seems to be disabled in your browser. You must have JavaScript enabled in your browser to utilize the functionality of this website. The primary difference between these two types of Stretch Wrap Film is the process in which they are created and manufactured.

These differences also make a big impact on the usability and price of the film. The cast process beings the same as blown, with beads of resin being fed into a heated barrel and being forced through a narrow slotted die. This 'sheet' of film the die produced is then fed along a rolling path that has been cooled, which solidifies the film.

It is then brought through the final stages of production and made into large rolls. This method is much faster than the blown extrusion method and also costs less, as more can be produced per man-hour. Machine stretch wrap is the most common type of film produced by this method. Beads of resin are fed through a heated machine that has a circular die.

The heated resin is forced through the die and then blown out vertically into a bubble. As this formed bubble finishes the process of being transformed into rolls of stretch film, it is cooled by the surrounding air. This type of film generally costs more to make because the output per hour is less than with cast films. Our blown hand stretch film is a common example of this type of film.

It has a much higher rating than our cast hand film for holding power and puncture resistance.

stretch film manufacturing process pdf

Additional stretching can be obtained easier through lower micron blown films Conversion Chart. Not crystal clear, can make reading and scanning harder, but has a lower gloss reducing reflections. Perfectly clear, makes reading and scanning in warehouse light easy, but a higher gloss makes reflections annoying.

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Rocket Industrial offers a variety of stretch wrap options. If you have questions on the best type of stretch wrap to use for your application, contact our packaging specialists. We will find the optimal packaging solution for you based on your needs and goals. Stretch Film Efficiency Calculator.When you ship products, they become vulnerable to sudden movements, improper handling and environmental elements. These dangers can result in damaged goods, unplanned labour and costly reverse logistics processes.

Stretch wrapping is a process of unitizing a pallet of goods to reduce the risk of damage before they reach their final delivery destination. We selected the premium stretch films in the market today to deliver the highest in quality standards.

Partnered with our revolutionary programs, we offer stretch wrap solutions that aim to reduce cost, improve performance and reduce waste. Our Wrap It Right program analyses your stretch wrap usage and finds ways to improve efficiency and reduce waste.

Our Packaging Specialist visits your facility for a hands-on review of your stretch wrapping process. Following the review, a comprehensive usage analysis is performed and areas for improvement are identified. Improvements can include using a better film for your application or altering the wrapping cycle for optimized film use. Regular updates are then performed as part of the Keep It Right program to ensure your stretch wrapping process maintains its peak efficiency.

Developed from the best stretch film technology available, these products are guaranteed to meet or exceed our customers' expectations on each load, every time. Our Crawford Guardian brand films offer solutions for both hand and machine applications. Contact us today for a FREE packaging audit of your existing stretch wrap materials and processes. Stretch wrap offers a variety of benefits to packagers and shippers. It holds loads together and reduces movement that causes damage, unitizes loads for easy handling and can increase a loads residence to external elements like dirt and rain.

Sudden stops, careless material handlers and rocky waves are only some of the dangers faced by your shipments. These hazards cause loads to shift and sway and can sometimes lead to toppling or collapse. Stretch film reduces the risk of damage by holding loads tightly together and locking them to the pallet. Load unitization is the process of packaging and transporting smaller cartons that have been grouped and combined into a single unit.

Once unitized a load becomes more manageable during handling as cartons are moved as a single unit, not one by one. A load unitized with stretch film also increases load security and prevents theft. It is virtually impossible to remove a single unit from a wrapped pallet without compromising the wrap and leaving obvious signs of tampering. Available in a variety of colours, stretch wrap film offers warehouse agents an easy and efficient method of distinguishing unitized loads at a glance.

A stretch wrapped skid offers added protection through increased stability and security. A properly wrapped skid protects the products inside from exterior elements.

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Standard clear stretch films offer protection against dirt that may be present when a load is stored in a warehouse or outside storage area.

For loads that are sensitive to water, top cover sheeting can be added to the wrapping process to create a fully encased load from top to bottom. UV resistant stretch wrap films are available for loads with light-sensitive products or for loads that may spend extended periods outdoors to prevent discolouration.

Stretch wrap or stretch film is a thin plastic film that is applied around a palletized load. Available in a variety of types for both machine and hand wrapping methods, stretch wrap offers an effective way to combat costly damages that can occur during transport.

The strength of the film provides the pallet with increased structure and containment capabilities, while the stretching of the film reduces its ability to loosen when under force. The taught film forms a constrictive force around the load, holding it in place.

Stretch film also helps to lock goods to a pallet, with the bottom wraps holding the load in place on the skid. Stretch wrap films are available in a variety of typesmaterials, colours and gauges. It is a versatile packaging material that offers an optimized film type for virtually any packaging solution. Stretch wrap film can be produced in both blown and cast formats for hand and machine applications.


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