What is Correx®? Everything you could need to know

If your business uses any returnable packaging or even warehouse picking bins, you may have heard of Correx®.

But what exactly is Correx®?

Correx® is a corrugated plastic material that is durable, hardwearing, water-resistant, and available in various grades and colours. Its use is widespread for signage, floor protection, and reusable packaging. The term Correx® is a trademark of Corplex.

In this guide, we’ll provide detailed information on Correx® specifications and properties, the various applications for corrugated plastic, alternative options, and the material’s sustainability.

The material and manufacturing process provide Correx® material with many advantageous properties.

It is highly durable, impact-resistant, and has an excellent strength-to-weight ratio. These properties make it ideal for heavy-duty packaging and handling applications.

Besides this, the material is 100% waterproof and weatherproof. As well as enhancing its longevity, these properties have made it popular for external signage and construction projects.

In addition to water, Correx® is also resistant to mould, fungi, and most chemicals.

Correx® uses an ethylene-propylene copolymer, which is resistant to impact. It exhibits high impact resistance over a wide temperature range, from approximately 0°C to 85°C.

Above 85°C, the material starts to soften, increasing the impact performance whilst losing structural strength. The material continues to soften until approximately 140°C, when the polymer begins to melt.

At temperatures below 0°C, Correx® becomes more rigid but also more brittle.

At -18°C, the impact strength is reduced by approximately 10%. While there are no impact performance measurements below -18°C, other industries routinely use polypropylene copolymers at temperatures down to 30°C (e.g., for ice cream tubs).

Down to temperatures around -30°C, you can expect the structure of Correx® to remain intact so long as the product is not subjected to unreasonable treatment. You can expect Correx® boxes to perform well in an environment such as on shelves, single-stacked.

The detailed performance characteristics of Correx® are as follows:

• Softening temperature (BS2782: 102D ISO 1306) 85°C.
• Crystaline melting point 160-175°C.
• Flash ignition temperature at 350°C.
• Calorific value 11000 cal. Kg.
• Specific heat 0.46 cal/gm°C.
• Limiting oxygen index (ASTM D 2863) 0.174-0.180.
• Burn rate (FMVSS 302) 5.3-8.2cm/min.

In addition to its beneficial properties, Correx® offers excellent versatility in conversion options. In fact, it is possible to convert Correx® in many of the same ways as with corrugated cardboard.

Correx® is easy to convert by die-cutting. This process involves using a sharp steel knife cutting form, similar to a cookie cutter. Specialist equipment compresses the corrugated sheets and cutting form together under high pressure to create the required shape and dimensions.

Die-cutting can also add creases to the material, making assembly easier (e.g., when folding to create a Correx® box or tray). Creasing is where the shape blades do not pierce through the material’s surface but create an impression to aid folding.

However, it is essential to consider flute direction. The material bends easily along with flutes, but folding across the flutes is more difficult.

CAD cutting is another type of conversion process that works on corrugated plastic. A large machine moves a sharp knife across the material, following a computer programme,  to create the required shape.

There are several additional features you can choose to add to Correx® products.

Options include moulded plastic handles, stacking corners, and edge profiles. These can be glued onto or screwed into the Correx® material.

Correx® provides a flat, smooth surface that enables high-quality printing. While material allows for an accurate representation of full-colour graphics, the bold hues of the other colour options combine well with single-colour print designs.

Correx® is suited to digital printing. This process involves being added directly to the surface of the Correx® material (rather than being transferred from printing plates as per analogue methods).

Digital printing of Correx® allows for full-colour and photographic-quality imagery. As a result, the material is widely used for external signage (most commonly for estate agent signs).

It is also common to print Correx® using screen printing.

This process involves forcing ink through a mesh screen onto the surface. Making certain areas of the screen resistant to printing ink effectively creates a stencil and prevents ink from transferring to the substrate. This, in turn, creates the required design.

Screen printing, however, is only suitable for one- or two-colour designs. As such, this printing method is often used for returnable packaging applications.

Due to its properties and ease of conversion, corrugated plastic is the material of choice for many applications.

Correx® is widely used for, but not limited to, the following applications:

• Returnable packaging.
• Picking bins for warehouses.
• Point of Sale stands (POS).
• Event shell scheme panelling.
• Floor protection for building sites.
• Specialist projects, including clean rooms and medical storage.

Correx® allows for the manufacture of returnable transit packaging.

As well as providing performance approaching that of moulded plastic containers, it can also be used over multiple trips (e.g., as part of a returnable supply chain setup).

Arguably, its main benefit, however, is the size flexibility it offers. Whilst moulded containers are only available in a limited range of sizes, Correx® tote boxes or returnable packs can be manufactured to the exact size that you require.

Custom-sized returnable packaging improves protection (as parts can’t move within the outer container) and warehouse and transport efficiency.

Correx® can even be used to create internal fittings, such as divider sets and layer pads, to further improve usability and protection.

Corrugated plastic is an ideal material to manufacture warehouse picking bins.

Widely used in 3PL and eCommerce fulfilment, Correx® picking bins enable logical ordering and storage of stock, as well as the “picking” of customer orders.

Similar to returnable packaging, using Correx® for your picking bins lets you source containers in the exact size you require. This approach can help maximise the available space in your warehouse.

Point of Sale (POS) is a great marketing and sales opportunity, and choosing Correx® for this offers many benefits. Advantages included supporting the weight of heavier products, being reusable, easy to clean, and being suitable for outside areas (e.g., in DIY warehouses or garden centres).

And, of course, Correx® FSDU (free-standing display units) and POS stands can include full-colour print to ensure accurate branding.

Correx® is also popular in several specialist applications.

The fact that it is easy to clean, does not shed any fibres and can be sterilised (including EtO, gamma, and autoclave sterilisation) makes Correx® a popular choice for healthcare, medical, and pharmaceutical applications.

Perhaps the most widespread use of the material, Correx®, is incredibly popular for external signage (most notably estate agency signs).

Correx® is weatherproof and easily printable, making external signage durable and long-lasting even when exposed to the elements.

Corrugated sheeting is popular for protecting finished products, such as walls or floors, on construction sites. This industry may also use Correx® for formwork and shuttering.

Correx® itself is a brand name of Corplex. However, several nearly identical materials go by different names.

Other brands and names for the material include Corvex, Corriflute, Corflute, Corriplast, and Twinplast.

However, there are also several alternatives to Correx® for both material and application uses.

Bubble-board is a three-layer plastic material with an interlinking internal cellular structure. This construction means it exhibits equal rigidity in both dimensions.

However, where it differs from Correx® is the available (optional) laminates that the material offers. Options include a cloth-covered version to prevent scuffs and a foam-laminated version that adds a layer of cushioning and impact protection.

These properties make it particularly suited to creating divider sets and inserts for reusable packaging.

When considering returnable packaging and picking bins, an alternative option is moulded plastic.

Being slightly more durable and longer lasting, moulded bins and containers can also be surprisingly cost-effective.

However, they are only available in a limited range of sizes, which can hinder the efficiency of handling, transport, and even storage.

Somewhat surprisingly, some heavier grades of corrugated cardboard are a suitable alternative to Correx®.

Heavy-duty double-wall and triple-wall grades (including Tri-Mite) offer strength approaching that of Correx®. They also offer the same size, printing, and conversion flexibility. Crucially, corrugated is considerably easier to recycle and most perceive it as more environmentally friendly than plastics. Corrugated packaging is also not subject to the Plastic Packaging Tax (unlike Correx®).

However, corrugated is typically used only for a single trip (making it more costly over a longer period). It also has little resistance to water, making it unsuitable for long periods exposed to the weather. It also sheds fibres, making it unfit for many cleanroom and precision-engineering applications.

Correx®, as polypropylene plastic, is 100% recyclable. However, it is a level five recyclable material, which is not accepted in UK kerbside recycling bins. As such, Correx® requires specialist recycling facilities.

Although Correx® is technically biodegradable, the process takes many years. The material does not readily decompose or biodegrade, as these processes rely on bacteria to consume and break it down.

To prevent environmental damage and ensure proper disposal, an effective recycling scheme is required.

If you are not already using Correx® at your business, there may be significant benefits to doing so.

However, due to the differences in protective performance, longevity, cost, and recyclability, it may not always be a straightforward switch. Saying that, there is a wide range of applications where using Correx® would significantly benefit your business.

At GWP, we are the UK’s leading independent converter of Correx® material. We have over 30 years of experience providing Correx® bins, boxes, totes, and other returnable packaging to a vast range of businesses and industries. Still, crucially, we also offer a range of alternatives (including corrugated cardboard), making us ideally placed to provide you with genuinely impartial advice.

If you would like further information and advice on what Correx® is or how you can use it in your business, please do not hesitate to get in touch with our team of packaging experts.