Biodegradable polymer PBAT is making a splash

Perfect polymers—polymers that balance physical properties and environmental performance—do not exist, but polybutylene terephthalate (PBAT) is closer to perfection than many polymers

Producers of synthetic polymers have failed to prevent their products from ending up in landfills and oceans for decades, and they are now under pressure to take responsibility

But both recycling and biopolymers face obstacles

PBAT combines some beneficial properties of synthetic polymers and bio-based polymers

Interest in PBAT is on the rise

Marc Verbruggen, former CEO of PLA manufacturer NatureWorks, now an independent consultant, believes that PBAT is "the cheapest and easiest way to make bioplastic products," and he believes PBAT is emerging as a superior flexible bioplastic , ahead of competitors such as polybutylene succinate (PBS) and PHA

Ramani Narayan, a professor of chemical engineering at Michigan State University, said PBAT's main selling point -- its biodegradability -- comes from ester linkages, not carbon-carbon bonds like non-degradable polymers like polyethylene

For example, PLA and PHA are polyesters that degrade when their ester linkages are broken

Some clever chemical reactions led scientists to invent PBAT in the 1990s as a bridge between aliphatic and aromatic polyesters

BASF produces polybutylene terephthalate (PBT), a polyester made from butanediol

Narayan believes that PBAT is a bit more biodegradable than PLA, which requires industrial composting to break down

Experts most often compare the physical properties of PBAT to low-density polyethylene, an elastic polymer used to make films such as garbage bags

PBAT is often mixed with polylactic acid, a polymer with rigid, polystyrene-like properties that provides stiffness

Novamont adds another dimension to the formula

Stefano Facco, the company's new business development manager, said: "Novamont has been addressing applications where degradability adds value to the product itself for the past 30 years

A big market for PBAT is mulch, which is placed around crops to prevent weeds and help retain moisture

Another big market is compostable garbage bags, used in food service and households to collect food and yard waste
.
Bags from companies like BioBag, which Novamont recently acquired, have been available at retailers for years
.

"The main ecological benefit of compostable plastics comes from their longevity, as these products help divert food waste from landfills or incinerators to organic recycling," said Joerg Auffermann, Head of the Global Business Development Team for Biopolymers at BASF.

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Over the years, the biodegradable polyester industry has moved into applications other than films
.
In 2013, for example, the Swiss coffee company launched coffee capsules made with BASF's Ecovio resin
.

An emerging market for Novamont materials is biodegradable tableware, which can be composted along with other organic matter
.
Facco said the tableware is already taking off in places like Europe that have passed regulations restricting the use of single-use plastics
.

With more environment-driven growth expected, new Asian PBAT players are entering the market
.
In South Korea, LG Chem is building a 50,000-ton-per-year PBAT plant that will open in 2024 as part of Seosan City's $2.
2 billion sustainable investment plan
.
SK Geo Centric (formerly SK Global Chemicals) and Kolon Industries are collaborating on the construction of a 50,000-ton PBAT plant in Seoul
.
Kolon Industries, a nylon and polyester manufacturer, provides the production technology, while SK provides the raw materials
.

The popularity of PBAT in the Chinese market is the greatest
.
Chinese chemicals distributor OKCHEM forecasts that China's PBAT production will rise from 150,000 tons in 2020 to about 400,000 tons in 2022
.

Some Chinese companies are increasing their investment in PBAT
.
The Hengli Petrochemical project with an annual output of 450,000 tons of biodegradable new materials, with a total investment of 1.
8 billion yuan, is located in Hengli (Dalian Changxing Island) Industrial Park.
It mainly builds two major projects of 150,000 tons/year PBS biodegradable plastics and 300,000 tons/year PBAT biodegradable plastics
.

Verbruggen sees a lot of motivation for investing
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First, all types of biopolymers have recently experienced an uptick in demand
.
Supply is tight, so prices for PBAT and PLA are high
.

In addition, Verbruggen said the Chinese government has been promoting "big development" in bioplastics in China
.
Earlier this year, the Chinese government passed a law banning the use of non-degradable shopping bags, straws and cutlery
.

The PBAT market is attractive to Chinese chemical manufacturers, Verbruggen said
.
The technology is not complicated, especially for a company experienced in polyester
.

In contrast, PLA is capital-intensive
.
Before making this polymer, companies need to ferment lactic acid from an abundant source of sugar
.
Verbruggen pointed out that China has a "sugar deficit" and needs to import carbohydrates
.
"China is not necessarily a good place to build a lot of capacity," he said
.

Existing PBDE manufacturers have been keeping pace with new players in Asia
.
In 2018, Novamont completed a project to convert a PET plant in Patrica, Italy, to produce biodegradable polyester
.
The project doubled its production of biodegradable polyester to 100,000 tons per year
.

And in 2016, Novamont opened a plant to make butanediol from sugar using fermentation technology developed by Genomatica
.
The 30,000-ton-per-year plant in Italy is the only one of its kind in the world
.

According to Facco, new Asian PBAT manufacturers may produce limited quantities of commodity polymer grades for large-scale applications
.
"It's not complicated
," he said
.
By contrast, Novamont will maintain its strategy of serving the professional market
.
"This is where we have some knowledge and some benefit to the market," he said
.

BASF is responding to the PBAT construction trend in Asia by participating in the construction of a new plant in China
.
The company licensed its PBAT technology to Chinese company Red Avenue New Materials, which plans to build a production plant in Shanghai with a capacity of 60,000 tons/year by 2022
.

"Positive market development is expected to continue with the upcoming new laws and regulations guiding the use of bioplastic materials in packaging, mulch and bags," said Auffermann
.
The new plant will allow BASF to "locally meet the growing growth in the region" demand
.
"

In other words, BASF - which started producing PBAT nearly 25 years ago - is now keeping up with the craze for new business as the polymer is becoming a mainstream material
.