IML

Historical Background

History

  • IML started in bottles
  • IML in North America started in the 1970s with Procter & Gamble and Owens-Illinois Packaging (now part of Graham Packaging). The first applications were blow molded HDPE bottles with paper labels coated with a heat-activated adhesive.
  • IML and IMD first crossed paths with injection molding in the area of structural-foam molding during the mid-1970s. Placing a preformed film in the mold was a way to cover up the surface swirl on foam parts and eliminate the trouble and expense of painting.
  • IMD found a warmer welcome in standard injection molding. It got its start in the late 1970s with woodgrain auto interior trim, according to sources at Avery Dennison, which supplied the printed films. Since then, auto companies have taken enthusiastically to preprinted foils and dry-paint films for interior parts with woodgrain and brushed-metal appearance and exterior parts that imitate paint or bright chrome. In the 1980s, GE Plastics helped introduce IMD to cell-phone covers. Although it was not a big hit in cell phones, IMD has since moved into PDAs and other handheld electronics, as well as major appliances.
  • Injection molding IML began in Europe in the 1970s with paper labels on PS substrates. An estimated 85% to 95% of rigid food packaging there now uses IML, as do some durable goods such as returnable beer crates. 
  • IML reportedly started in the U.S. in the early 1980s. Shape Inc. in Biddeford, Me., was one of the first to get into IML injection, taking a license in 1982 from Cerbo in Sweden, which held patents on a technique to inject the melt through the label. In 1983, Shape applied the process, using Cerbo’s automation, to production of video cassette sleeves in a two-cavity mold.
  • Problems with label quality, feeding, and handling kept IML activity low-key in the U.S. until the mid-1990s, when it was rekindled by molders’ attempts to eliminate secondary operations, reduce the scrap rate from post-mold labeling, and to produce a “no-label” look similar to that of blow molded articles. Adding a label in-mold also could permit a reduction in wall thickness while maintaining the part’s strength—a benefit not available with any other labeling technique. And the permanence of an IML label also appealed to safety issues, as a way to be sure the listing of product ingredients, health warnings, or UPC codes stayed with the package through its life cycle. Injection molders of durable goods also acquired a taste for IML, applying it to toys, lawn and garden products, all-terrain vehicles, trash containers, and even tractor body panels.

What is IML?

IML is the ideal packaging for ...

... food containers such as ...

  • ice creams, 
  • yoghurts, 
  • sauces, 
  • butter, 
  • spreads, 
  • etc., ...

... as well as ...

  • cosmetic and personal care products,
  • petrochemical and paint, 
  • household products, 
  • and other molded plastic parts.

Distinct attributes of IML include ...

  • permanency because labels become part of the wall of the container, making it non-peelable.
  • no-label look because part of the label becomes transparent during the molding process.
  • The use of robotics in IML assures the accuracy of label placements and avoids missing stickers.
  • easy removal of the label since in-mold labels detach from the molded container after 6 months.
  • The format provides remarkable flexibility, labels adapt to the container’s form and surface. This gives product designers more room to create standout brand labels.

What are the advantages of IML compared with other label types?

  • Advantages of IML compared to glue-applied Cut & Stack
    Require no glue during application as they are fused directly to the plastic container at the molding stage. Because of this, the labels enjoy an improved shelf life. You get a finished plastic product that is resistant, durable, and attractive.
  • Advantages of IML compared to self-adhesive labels
    They provide a "no label" look. These labels have a nicer look and feel as they are seamlessly integrated without edges. In-mold labels are hence not vulnerable to environmental damage and their print quality is preserved.
  • Advantages of IML compared to shrink sleeve labels
    Shrink sleeve labels: need special design software + secondary operations during production. The finished product is therefore more expensive to manufacture. IML label: savings on time + raw materials, drastically reduced amount of waste
  • Advantages of IML compared to dry offset
    IML: a simplified production process-->accelerated changeovers. It eliminates certain chemicals used in the dry offset process. In-mold labels provide exceptional print quality (high-quality images + colour consistency) + a larger print area.

Basic Overview of Market Segmentation

Segmentation Parameters

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IML Technologies

IML-IM

  • The injection molding process consists in injecting a heated and molten plastic polymer into a steel mold.
  • The printed label is placed beforehand inside the same mold. When the label meets the molten polymer inside the mold, they fuse together. The mass then cools off and solidifies into the shape of the mold with the label fused to the container/part wall.
  • Melting and injection temperatures of the plastic are in the range of 200 – 250 °C (depending on the type of plastic). For fast cooling of the material, the steel mold is usually chilled, and thus, the real temperature encountered by the label inside the mold is somewhat lower. The whole process is usually automated and lasts up to 5 seconds per injection.
  • The injection molding process comprises the following steps (also indicated by the red balloons in the diagram).

Video of IML-IM process

Video 2 of IML-IM process

Video 3 of IML-IM process

IML-BM/IML-EB

  • Blow molding is a technique used for the production of hollow plastic parts such as bottles. The label is placed inside the steel mold beforehand. Then the pre-extruded hot plastic material (called “parison”) is introduced, and the two-parts mold closes on it.
  • With heated and high pressurized air (“blowing”) the plastic is stretched into the shape of the mold, and is fused together with the label placed at the mold’s walls.
  • The process temperature of the molten plastic is a bit lower than in the injection molding process, being in the range of 180 – 200 °C.
  • Depending on the type of plastic; there are some special grade films that can be blow-molded at very low temperatures of 120-130 °C.
  • For fast cooling of the material, the steel mold is usually chilled, and thus, the real temperature encountered by the label inside the mold is somewhat lower.
  • The whole process is usually automated and lasts up to 10 seconds per part (depending on the size).

Video of IML-BM process

IML-TF

  • During thermoforming, unlike the injection and blow techniques, the thermoplastic molding material (in web or sheet state) is fed into the molding press. The process uses heat and pressure to shape the material. As for the other molding processes, the label is placed inside the mold beforehand, and when it meets the heated polymer inside the mold, they fuse together. The mass then cools off and solidifies into the shape of the mold, with the label fused to the container/part wall.
  • The process temperatures of the plastic here are the lowest of all molding processes, being in the range of 130 – 150 °C (depending on the type of plastic). For fast cooling of the material, the steel mold is usually chilled, and thus, the real temperature encountered by the label inside the mold is somewhat lower. The whole process is usually automated and lasts up to 5 seconds per part.
  • Due to the lower process temperatures and pressure, compared to the other techniques, it is highly recommended to NOT use standard IML substrates used for injection or blowing, to avoid the resulting poor adhesion. This was the major obstacle for the thermoforming process in the past. In recent years many label films were developed specifically for thermoforming labeling (for example, coex PP, which solved the adhesion issue by including a special low-melting PP layer), but at a somewhat higher cost.
  • This may be the reason why this technique still has the lowest market share among the in-mold labeling production processes.

Video of IML-TF process

Which technology is it?

  • IML-IM
  • IML-BM
  • IML-TF

Video of dry offset process

How does IML-BM/IML-EB work?

  • Step 1
    The die-cut label is placed in the two-parts mold, on both walls.
  • Step 2
    Vacuum suction holds the label in place; the parison is introduced between the two open mold parts.
  • Step 3
    The mold closes; heated high pressurized air is blown inside the parison, expanding it towards the mold walls until it acquires the shape of the mold; the label fuses with the plastic.
  • Step 4
    The plastic cools down; the mold opens and the bottle is ready together with the fused label.

IML application to container type

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Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.

IML application to container type

  • IML-BM
  • IML-EB
  • IML-IM
  • IML-TF
  • IMD

Container Substrates

Container Substrates

Main Container Substrate Types

  • PP (Polypropylene) — The most used type in the IML industry. Mainly used for FMCG (fast-moving consumer goods). In recent years PP is also being successfully tested and used in more durable applications. (PP) is the overall designation for a series of weldable thermoplastic polymers which stand out by way of their great hardness, rigidity and heat resistance. PP is processed, for example, in sheets, buckets and bottles, and its pollutant-free incineration permits ecologically compatible disposal.
  • PE (Polyethylene) — Used mainly in blow molding market for bottles. (PE) is easily recognized by way of its soft, wax-like surface with pronounced non-stick properties. It displays a low density, but at the same time high strength, hardness and resistance to chemicals. PE is used, for example, for environment-friendly self-adhesive foils and extremely tear-resistant sheet and roll materials, such as the fabric-like DuPont Tyvek.
  • PS (Polystyrene) — Used in fast food and sweets markets, such as noodle cups and chocolate boxes.
  • ABS (Acrylonitrile butadiene styrene) — Used for long-life products such as lunch boxes.
  • PC (Polycarbonate) — Used for transparent products, such as beer glasses and automotive parts.
  • PET (Polyester) — Used for high temperature and high barrier applications.
  • Sometimes a blend of resin types is used to achieve multiple characteristics for the desired part, like the ABS- PC blend used in the automotive industry for dashboard decorations.

Molding Specifics

 

RESINS (Common)

TEMP. in °C (Normativ)

LABEL Specialities

CYLCE TIMES (Average)

IML-IM

PP, PE, PS, ABS, PC

220-250

  5

IML-BM/IML-EB

PP, PE, PET

180 -200

120-130

back layer

with lower melting point

10

IML-TF

PS, PS-multilayer (such as PS/EVOH/PE), PP-multilayer (such as PP/EVOH/PP) as well as APET, even materials made of PLA (polylactic acid) biopolymer

130-150

back layer

with lower melting point

5

IML-IMD

PP, PE, PS, ABS, PC

DEP DEP DEP