Here are some of the most frequently asked questions we receive regarding shipping & packaging materials. We will try to keep our answers short & basic.
 
Stretch Film Differences
What is the difference between cast & blown films?
 
There are 2 methods of stretch film extrusion; either "Cast" or "Blown". Most films are made from linear low density polyethylene. These begin as pellets of "resin" and are melted to create film. The linear low density polyethylene "line" up or "stack" up to form a greater strength than conventional or "regular" low density film where tensile strength is not as important. Modern extrusion methods "layer" films for greater strength puncture resistance.

Cast film is made when the resin is melted & extruded through a horizontal flat die and onto a "chill" roll. There is increased machine direction tensile strength and increased "cross direction" tear strength. The gauge profile is also easier to maintain than blown films. There is generally greater clarity to the film. What this means to the end user is film that generally runs faster & more efficiently through equipment. Most cast films also hold your load tighter. They also run more quietly when pulled from the roll.

Blown film is made when resin is melted & extruded forced (blown) upward through a circular die. Air inside the cylinder forms a bubble rising 30 to 50 feet & is cooled by air. It is then flattened & slit into the rolls.

Blown film is generally "softer" thereby yielding greater stretch and better corner tear resistance. It tends to be cloudier but modern methods have cleared much of this up. It is also much tackier than cast but the downside is that it is also much noisier coming off of the roll. Blown films usually have better cling for cold applications.

So it may come down to a subjective decision… do you need better "cling" or better "load retention"? Is noise a factor in your plant? Are you looking for speed & greater pre-stretch?

Most manufacturers make both cast & blown. If you speak to one of our film product managers we can guide you to the best method.
 
 
Corrugated Differences
What is "fluting" and what are the differences?
 

All corrugated has fluting. It is the ruffy or rippled layer between smooth layers of paper.

Corrugated is mostly made from byproducts of the lumber industry. But today one of the biggest components is old corrugated. Recycling is very big in corrugated materials.

The outer smooth layers in corrugated are called "liner-board" or "liners". Fluted or corrugated medium makes up the middle. The various flutes are: A,B,C,E & F.

A-Flute is the original flute invented. It has the highest flute size and therefore is the thickest overall corrugated board. It has 36 flutes per linear foot; it is the best for cushioning & stacking of fragile items. It also is very good for stiffness & short column crush resistance.

B-Flute was the 2nd flute used in the corrugation business. It has a lower arch that A-Flute. B-Flute has over 50 flutes per foot. Because of it's stiffness it is excellent for high quality printing and die cutting. B-Flute is preferred for high speed, automatic packing lines.

C-Flute actually splits the difference between A & B. There are 42 flutes per foot. It is excellent for printing, cushioning & stacking. It is actually the most common of all flutes.

E-Flute has the most flutes per foot at 94. This gives it the greatest crush resistance and the flattest surface for high quality printing. E-flute is ¼ the thickness of C-flute; it can therefore reduce the overall size of your box & save space. Because of its thin profile & relative strength it can often replace folding cartons or solid fiber containers.

F-Flute is one of the newest flutes. The idea was to make packages with low fiber content. It is a little more than ½ the thickness of E-Flute. The concept is to have less solid waste.
 
 
Carton Sealing Tape Differences
What are the differences between the various adhesives?
 
General carton sealing tape is primarily done with Polypropylene tape. It comes in a variety of thicknesses, colors and sizes. The most common is a 2" width and is applied by the use of a hand-held tape dispenser. It is usually 110 yards long. Clear & Tan are the most common colors, but we do quite a big business in white and custom printed tapes. The next most common size is machine applied. This is generally 1000 yards long.

The 3 types of adhesive are: Acrylic, Hot Melt & Natural Rubber.
 
  Acrylic
  This is one of the easiest adhesives to manufacture. It takes only 2 steps. As a result, performance is more consistent. It is noted for it's clarity on clear tape. Acrylic has superior performance in extreme temperatures so it is favored in refrigerated or freezer applications. It is best when used in hand applied applications.
   
  Hot Melt
  This adhesive is noted for it's quick stick. It sets & sticks immediately. It is favored in machine applied applications because of it's quite unwind & fast stick qualities. There are some issues with hot melt fading or yellowing over time, especially if left in direct sunlight; this will only be evident in clear tape. It is also not very good in extreme temperatures.
   
  Natural Rubber
  This adhesive is the most aggressive of the three. It has excellent adhesion on a wide variety of surface conditions including recycled boxes, hot & humid conditions and cold room storage. Natural rubber is by far the superior adhesive but it is by far the most expensive.
 
 
Box Differences
How do I know what strength or style I need?
 
Essentially, the situation dictates the rule. There is no "set in stone" formula to tell you product "A" goes into style "A". Variables include the size & weights of your products; how you are shipping your products; are they fragile or resistant to damage; is this for retail or industrial use; is "eye appeal" important… the list goes on but these are the essentials.

As a general guideline, where products are shipping by truck, pallet or courier (yes even UPS) a "Regular Slotted Carton" (RSC) will do the job. When added strength is required, for example, for very light-weight fragile items a "Full Overlap" (FOL) will better protect your goods. A "Half Slotted Carton (HSC) is essentially a tall tray and works well with items that are going directly from your plant to a user, or where ventilation is important (such as produce).

Our preference in designing & selling boxes and containers is to see the product and meet with our customer to determine answers to these and other questions.

Below is a chart for an overview to help determine which strength may best suit your needs.
 
 
Edge Crust Test (ECT) vs. Bursting Test and Maximum Weight
 
Bursting Test
Edge Crust Test
Maximum Weight of Box and Contents
Singlewall
125
23
20
150
26
35
175
29
50
200
32
65
250
40
80
275
44
95
Doublewall
200
42
80
275
48
100
350
51
120
450
61
140
620
82
180
Triplewall
700
67
240
900
80
260
1100
90
280
1300
112
300