Custom Printing: Blow-Mold and Injection-Mold Labeling

Photo purchased from … www.depositphotos.com

Few things sell products like custom labels. Think about the confusion you’d experience if you walked into a grocery store, went to the hair products, and all the bottles just said “shampoo,” or “conditioner.”

Or, worse. What if every package in the store was just labeled “food”?

Labels do a lot of different things, not the least of which is identify the contents of a package and display the “brand.” That is, beyond the shampoo, you’re really buying all the intangibles, the feelings and values, which the logo, ink coloration, and imagery of the brand imply and promise.

This is why it’s smart to understand custom label printing if you’re a designer, print buyer, or commercial printing supplier. Labels have immense power.

In-Mold Labeling

When you get a moment, do what I just did. I just went into the bathroom and checked out some of the plastic bottles. Some had labels stuck to them. Others seemed to have clear shrink-sleeves covering the bottles, with both transparent areas and printed areas. Still others seemed to have durable printed labels burned right into the plastic. I’d initially assume they were samples of custom screen printing, but these labels seemed to be even more durable and scratch resistant.

So, my assumption now is that the in-mold labeling I had read about earlier in the week (because I had never seen the term before) pertains to the final sample noted above. Mark my words. You’ll be surprised if you dig around in your bathroom, or even under your kitchen sink, just to observe how companies are labeling their products these days.

How In-Mold Labels Are Made

With my interest piqued, I did some research. In-mold labels are positioned in the mold (the structure that gives form to the molten plastic from which shampoo and other bottles are made) before the molten plastic is added.

(Think about a fine-art sculptural mold, which is built around a wax or clay original sculpture. Once the outer mold has dried, the inner sculpture is removed, leaving a hole or cavity–or negative image of the art–within the mold. First you pour molten bronze into the cavity in the mold. Then, once the bronze has cooled and solidified, you can remove the mold, and you’ve got the bronze statue.)

If you shift your mindset a bit, you can envision molten plastic being introduced into a mold for a bottle of shampoo. It’s the same concept (although the inside of the bottle obviously won’t be solid plastic).

There are two ways to do this: blow-mold and injection-mold manufacturing. Keep in mind that the custom printed label is already in position in the mold, so all you really need to do is add the molten plastic for the bottle, which then fuses with the pre-printed film label, eliminating the need for additional labeling, streamlining the manufacturing process, and even facilitating waste and recycling—all while improving label durability. Once the in-mold-labeled bottle is empty, you can even grind it up, melt it, and turn it into a new bottle.

Blow molding involves introducing a lump of molten plastic or polypropylene into the bottle mold and then blowing air into the plastic until it conforms to the interior surface of the mold (i.e., up against the in-mold labeling). If you think back to your high school history class, you may remember seeing pictures of people blowing glass in Colonial Williamsburg, VA. Or, you may have seen the same thing done at the local Renaissance Faire.

This is essentially the same process, using plastic instead of glass and automating the process. Blow molding, which was the original intent for in-mold bottle labeling, is preferred for hollow bottles and other closed containers, especially those that are medium to large in size.

In contrast, injection molding is just what the name implies. Molten plastic is injected into the mold (without blowing air into the molten plastic). You might use this process for small bottles, or for open tubs that contain butter or ice cream.

Both of these options yield the following benefits. The in-mold labels are waterproof, scratch-proof, and resistant to chemicals. (Think about the aggravation that would ensue if all the labels in the damp bathroom started to come apart in your hands. In-mold labeling avoids this.)

Implications of Bottle Labeling

I did some research and found some more implications of bottling and bottle labeling. First of all, as a culture, we buy plastic bottles full of food, beauty products, and cleaning agents. When you include commercial products, you add a huge number of industrial items that also need containers and custom printed labels.

According to Wikipedia, packaging (which includes but goes beyond labeling) solves a lot of problems:

“Packaging contains, protects, preserves, transports, informs, and sells” (Wikipedia, Product Packaging).

More specifically:

1. 1. Packaging protects the contents of a bottle or other container from heat or cold, physical shock, and vibration.

1. 1. It keeps out moisture, dust, oxygen, and other contaminants. (This is called “barrier protection” in the packaging trade.) It is especially important for foods and pharmaceuticals. In some cases the packaging can even control the temperature of the contents and thus preserve its longevity and usefulness—i.e., keep it “clean, fresh, sterile, and safe” (Wikipedia, Product Packaging)–throughout the product’s intended shelf life.

1. 1. Packaging “contains.” That is, if you’re buying a bottle of laundry soap powder, it keeps the granules together and off the floor. Moreover, packaging can group together a number of similar items (like when you buy a box of fruit-and-nut power bars at the gym), and it can even group a number of cases of the same power bars on a wrapped pallet in a warehouse. In all of these cases, access to information (what’s on the skid) and branding (which company owns the skid) are paramount.

1. 1. Packaging displays vital information. If your product is aspirin, you will probably need a lot of room on the label for information regarding what to take, dosage amount and time, what the ingredients are, etc. Labels can include all of this as well as expiration dates, lot numbers, sourcing information, and government-required data for anything from food to medicine to chemicals.

1. 1. Packages (and their labels) can help to ensure safety. For instance, if tamper resistant devices have been added (either physical barriers or notations with security ink), you will know whether to discard medicine or food that may have become compromised. Security inks used for custom printing can also indicate that the items in a package are authentic and not counterfeit (a specific medication, for example).

1. 1. Portion control. Packaging helps you contain a specific amount of a product: something as simple as a packet of salt or sugar, for instance. Or, more critically, packaging can contain a precise, single dose of a medication.

1. Marketing and branding. With all of the images that accost us on a daily basis, it has become essential for companies to set themselves (and their products) apart from all competitors. Labels, shrink-sleeves, flexible packaging, corrugated board, and folding cartons, to name a few, all sell not only the product but also the manufacturer. Using color and type, a manufacturer has to inspire your confidence that you’re buying the exact product you want and need. Plus, you have to trust that the contents are safe and timely: exactly as you expect them to be. For a bottle and custom label, that’s awe-inspiring power.

This entry was posted on Wednesday, July 14th, 2021 at 1:29 pm and is filed under Label and Sticker Printing. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.