What Is Stretch Film Wrap?

What is Stretch Film Wrap?

Stretch film is a highly stretchable plastic film that can be used to securely wrap around goods. The elastic restoring force keeps the objects tightly together. In contrast, shrink wrap paper is loosely covered around the items and only to shrink tightly as a result from heat.

Stretch film is used in the sales and transportation of various products, and its main function is to stabilize, cover and protect the product.  The shrink film must have high puncture resistance, good shrinkage and a certain shrinking stress. When being stretched, the film should not produce holes.  Since shrink film is often put to outdoor uses, it is usually necessary to add anti-ultraviolet agent.

General specifications of Stretch film

a. Thickness:  15 - 50 microns
b. Width:  5cm - 150cm 
c. Elongation:  200% - 400%  
d. Color:  transparent (other colors can be customized according to customer requirements)

What is stretch wrap film made of

The most common material for stretch wrap film is linear low-density polyethylene or LLDPE, which produces copolymerized ethylene and α-olefins, the most common being butene, hexene and octene. The use of higher alpha-olefins (hexene or octene) can enhance the properties of the stretched film, especially in terms of elongation at break and puncture resistance. Other types of polyethylene and PVC can also be used. Many films have an elongation at break of about 500%, but they can only be stretched to 100-300% in use. After stretching, elastic recovery will be the force to keep the wrapped items tight.

Control of stretch film's adhesiveness

Good stickiness is the key property that makes the stretch wrap film cling securely over the packaged goods and make them a solid and stable whole. There are two main ways to obtain the stickiness of the stretch wrap film: one is to add PIB agent or its masterbatch to the polymer and the other to blend VLDPE in.

(1) PIB (Polyisobutylene) is a translucent viscous liquid and extremely difficult to manipulate in its natural state, direct addition of which requires special equipment or modification to the equipment. Therefore, PIB masterbatch is mostly used instead. There is a process for the transfer of PIB, which usually takes three days. Besides, its stickiness is also affected by temperature. The adhesiveness is strong at high temperature and weakened when the temperature is low. Also, the stickiness is greatly reduced after stretching. The finished film is preferably stored in a certain temperature range (suggested storage temperature is 15℃～25℃). 

(2) Blended with VLDPE (Very low density polyethylene).  Its adhesiveness is slightly poorer, but no special requirements for the equipment to add it. And its adhesiveness is relatively stable, and not limited by time, but also affected by temperature. It is relatively stickier when the temperature is higher than 30°C, and slightly worse when the temperature is lower than 15°C. The desired adhesiveness can be achieved by adjusting the amount of LLDPE in the adhesive layer. This method is mostly used for three-layer co-extrusion.

What is pallet stretch wrap

Pallet stretch wrap or pallet cling wrap is one of the major applications of stretch film. Pallets are used in goods shipping to greatly facilitate the loading and transit of goods.  As each pallet is handled as a unit, stretch wrap is a must to guarantee that all cartons on the pallet hold firmly as one block. You can either hold a pallet wrap handle to wrap pallets manually (as in the below picture) or employ a pallet stretch wrapping machine to automatically wrap the pallets when there's a regularly large quantity.

Some people seem to be confuse stretch wrap with Shrink Wrap Packaging. Although they are similar in terms of packaging and protecting goods, they are quite different!

What Is Clamshell Packaging?

A clamshell, as the name suggests, is  the shell of a clam. And clamshell packaging is a type of packaging that resembles a clamshell both in terms of shape and its opening-and-closing mechanism. Therefore a clamshell packaging is a one-piece box or container consisting of two identical halves, which are joined by a sort of hinge on one end, and  open and close with a snap-on closure mechanism on the other.  

The reason that clamshell packaging is popular with many consumers may be it's compact, elegant and convenient to use. Clamshell packaging boxes are often made of various plastic materials, and now more and more paper materials with the aroused environmental awareness.

What is clamshell packaging like?

Clamshell CD Cases - Plastic

Wooden Clamshell Packaging

Cardboard Clamshell Gift Box

Types of Product Packaging

Product packaging is an important part of the product. It not only plays a protective role in the transportation process, but also directly affects the overall quality of the product. 

What are the types of packaging?

The following are our commonly used packaging materials and packaging: 

Inner packaging 

⑴ Plastic bags: The U.S. line generally requires heat sealing and the material is high-pressure PE material; unless the customer has specified requirements, it is not allowed to use PP material. ⑵ OPP bag: It has good transparency, but it is brittle and easy to break. It is mostly used for the packaging of candles, toys and other products, which is often required by European customers. ⑶ Color boxes: divided into corrugated color boxes and non-corrugated color boxes. ⑷ Ordinary brown corrugated boxes: commonly used are 3-layer corrugated boxes and 5-layer corrugated boxes. After the product is packaged, it is generally sealed with tape. ⑸ White boxes: It can be divided into corrugated (3-layer or 5-layer) white boxes and non-corrugated white boxes. Products are generally sealed with tape after packaging. ⑹ Display boxes: There are many types, mainly color display boxes, display boxes with PVC lids, etc. Through this packaging, the products in the box can be seen directly. ⑺ Plastic bag with header card. ⑻ Blister card. ⑼ PVC box or PVC bucket. ⑽ Shrink film; also called heat shrink film. Small toys, candles and other products use this type of packaging. ⑾ Hang up the card. ⑿ Egg compartment. ⒀ Back card. ⒁ Gift boxes; mostly used in the packaging of jewelry, stationery and other products, and there are many types. ⒂ Others.

Intermediate packaging 

mainly includes plastic bags and corrugated box packaging. The types of corrugated boxes mainly include FOL, TUCK TOP BOX, etc. 

Outer packaging 

Generally use export cartons, i.e. 5-layer corrugated boxes, and mainly with B/C flute for corrugation. The formula for calculating the outer carton price is:

(Length+Width+8)/100 x (Width+Height+6)/100 x unit price per square.

The unit of length, width, and height are all CM. For example, if the size of an outer box is 60 X 30 X 40 CM, the price is

(60+30+8)/100 x (30+40+6)/100 x 6 (market price) = 4.47 yuan (China's RMB).

What Is Shrink Wrap Packaging?

 Shrink wrap is an important packaging method, especially for retailing and shipping.

What is shrink wrap packaging

Shrink wrap packaging is to use shrink plastic film to tightly wrap products or packages outside by heating. The plastic film will shrink and cling tightly to the surface of the product or package to pack. 

What is heat shrink wrap film made of?

The materials used for heat shrink wrap are mainly various thermoplastic films. PVC plastic film has been the most used in shrink wrap before. But nowadays, with the market demand diversified, PVC shrink film gradually decreased in share, and many other heat shrink film materials such as PE, PP, PET, OPP, PVDC, POF and more multilayer co-extruded heat shrinkable films developed rapidly and became the mainstream of the market.

Advantages of shrink wrap packaging

There are many advantages of heat shrink wrap. That's why it gets so popular in retail packaging. Some of shrink wrap benefits are: (1) Fully show the packed item due to the high transparency of shrink plastic. (2) Items being shrink wrapped can be kept moisture-proof, and dust free. (3) Shrink wrap provides the products a certain cushioning and thus protect them from external impact. Especially when packaging fragile utensils, it can prevent them from flying when broken. (4) Offer some degree of tamper proof.

How to shrink wrap a box?

To shrink wrap goods, boxes or cartons, you need some kind of shrink wrap tunnel/machine as below. Of course, there are a wide variety of brands and models available.

But if you're about to shrink wrap odd items, or for home use, for example to shrink wrap shoes, then you can simply do it with the help of a hair dryer. In this case, you need to purchase heat shrink wrap bags of right size. Put your items into the heat shrink bag before blowing it with the dryer.

Difference between heat shrink wrap and stretch wrap packaging

(1) Shrink wrap is through the contraction of plastic film, while stretch wrap the expansion of  plastic film. They wrap just the opposite ways.

(2) Different in ways of application. Shrink wrap packaging generally can't be finished without the help of heat, while stretch wrap can be applied anywhere by stretching the film with bare hands (though there are stretch film wrapper available for industrial use).

(3) Different in plastic properties. Stretch film is soft and more flexible. But heat shrink wrap film, on the contrary, tends to be fragile.

What Is A Blister Pack?

According to Oxford Dictionary, "blister" refers to a swelling on the surface of the skin that is filled with liquid and is caused, for example, by rubbing or burning. That's the original meaning. It also gives the word's derived meaning as "a similar swelling, filled with air or liquid, on metal, painted wood or another surface"! And the second one is what we're talking about, blister pack!

What is a blister pack?

1. Blister Pack for Medications

A Blister Pack may be a pack in which pharmaceutical tablets, capsules or small pills are sold, with each individual item in its own separate plastic or foil section on a piece of card, that resembles blisters.  And this application may be more pertinent to its original meaning of a kind of skin symptom.

2. Blister Packaging for General Consumer Goods

But blister packs have been put to more extensive applications than pharmaceuticals, as you probably have seen a lot of them in any supermarket or grocery store. And maybe, this is the blister packaging in general sense that most people are looking for! Below are some examples: