Putting Carpets to the Test - Wacker Chemie AG


Putting Carpets to the Test

WACKER employees in Dalton, Georgia, set fire to new carpets and torment them for days at a time with office chairs – all to the benefit of customers.

The motor propels the base of an office chair over the carpet sample up to 25,000 times. Loaded down with the equivalent of a 90 kg human being, the casters race across the pile, moving in eccentric circles. The machine reverses its course so that the casters can torment the carpet from all directions.

The caster chair test is just one ISO method that John McClurken and his team at the WACKER Technical Center in Dalton, Georgia (US), use for simulating in just a few hours what office and residential carpeting undergoes over the course of several years. There’s a reason why WACKER is interested in carpet durability: the product life of a carpet is highly dependent on the primary coat – the base layer of the carpet coating where the loops of the pile are secured to the backing. This is precisely the application for WACKER’s vinyl acetate-ethylene copolymer (VAE) dispersion binders.

The Heart of the American Carpet Industry

The US state of Georgia is the source of 45% of the world’s carpet production, and Dalton is the hub of the American carpet industry. This small town is home to WACKER’s research and training center for the carpet industry.

John McClurken is the lead chemist at WACKER’s research and training center in Dalton, where he served customers in the carpet industry for over two decades. Employed at WACKER since 2009, this busy applications chemist can travel from his office in Dalton to most major carpet manufacturers in an hour or less – and he knows exactly where his customers’ concerns lie.

The price of oil is one key indicator of the mood among his customers: most carpet backing, after all, is coated with compounds based on styrene-butadiene- latex (SBL) binder, which is made from petroleum. McClurken’s moment arrived in 2012, when oil prices climbed to new heights and he worked tirelessly to persuade carpet manufacturers of the benefits of VAE binders. Because VAE is made from natural gas – an inexpensive commodity in the US – it offered a considerable price advantage. His customers had major reservations in the beginning. But as the price differences between the two binders increased, one eventually said, “OK, let’s give it a shot.”


“We Were All a Team”

According to John McClurken, the lead chemist at WACKER’s research and training center in Dalton, “You can’t be innovative unless you’re a partner to your customers.”

For months, McClurken’s team worked with manufacturers’ technicians to develop the right formulations. Their aim here was more than simply finding the right composition for the carpet backing adhesive – they also had to optimize the formulation for use on manufacturers’ machines. “We were all a real team,” McClurken recalls.

Actual application would show whether the new formulation could keep its promises. Over the course of one year, many square meters of the new carpet were laid in schools, churches, commercial buildings, and private homes. At the same time, WACKER technicians simulated an office chair rolling across the carpet thousands of times while customers rotated a carpet-lined drum for days with a metal ball inside. The result? The VAE binders proved to be a worthy replacement for the SBL used up until that point – and they cost less. Before long, a large number of American carpet producers had switched over to VAE backing adhesives.

VAE Stands for Lasting Quality

WACKER carpet lab: the delamination test is used for determining the strength of the bond between the carpet backing and the wearing surface.

Now, four years later, oil prices are half what they were. Does the change in price mean that the pendulum will swing back in favor of SBL? Surprisingly, that has only been true of budget carpet product styles, with VAE-coated carpets remaining the preferred choice in many commercial applications.

Commercial customers, after all, are looking for a safe bet. The carpets used in hotel rooms, schools, and offices have to last a long time, and they must not pose any health or safety hazards. Thanks to its excellent durability, low odor, and superior flammability resistance, many interior designers turn to VAE-coated carpeting. For example, the outstanding binding power of VAE dispersions ensures that the backing and pile of a carpet are difficult to separate.

A Good Indoor Environment – Right from the Start

We all no doubt know the odor of new carpet. The cause is usually some by-products from styrene-butadiene polymers outgassing from the carpet backing. If it were in your hotel room, you might complain. For that reason, more and more architects are recommending that their customers look into alternative products bound with VAE. The advantage of these aqueous VAE-based carpet backing adhesives is that they emit virtually no volatile organic compounds, thus eliminating the typical carpet smell.

VAE backing adhesives also perform well when it comes to fire safety. Unlike those formulated with styrene-butadiene, carpet backing adhesives based on VAE are more flame resistant by nature. The furnace-chamber test shows WACKER customers just how flame resistant the backings are. Compounds made with styrene-butadiene are completely consumed in a cloud of black smoke, which is due primarily to the styrene component in the polymer. There is very little smoke when VAE grades (no styrene) are used and the fire goes out entirely in many cases. McClurken and his team now no longer have to explain that carpets with VAE binders are simply the better choice.

A Tough Test

Using standardized tests that simulate daily wear and tear on carpets, WACKER experts in Dalton focus their attention on certain key questions: Are the carpets tough enough for the target application? When do they begin to wear?

Carpet Tests Technical Center Dalton

  • Caster Chair Test

    The caster chair test simulates an office chair rolling over a carpet thousands of times.

  • Vettermann Drum Test

    In the Vettermann drum test, a metal ball rolls around for days inside a rotating drum lined with carpet.

  • Treadwheel Test

    In treadwheel test simulates the effects of shoes to determine how well a carpet holds up to heavy foot traffic.

  • Delamination Test

    The delamination test assesses the bond between the secondary backing and the pile. A stronger bond means a more durable carpet.

  • Tuft Tear-out Strength Test

    The tuft tear-out strength test assesses how well the carpet fibers are bound to the backing material.

  • Furnace-Chamber Test

    The furnace-chamber test involves setting fire to the carpet samples. Interesting fact: Carpets bound with VAE are significantly less flammable than those based on styrene-butadiene latex.