Inside Green Innovation: Progress Report - Third Edition highlights:
- Global bioplastic patent filings are higher than ever before.
- South Korea is the leading country in new patent filings, possibly based on new government policy. Two of the top three filing companies are from South Korea.
- However, unlike a previous peak in 2003, the current surge is a global effort.
- Filings relating to polylactic acid (PLA), polyhydroxyalkanoates (PHAs), and butylene-based polymers have grown, but starch-related filings have stalled.
- Filings from the top companies generally relate to improving mechanical properties, aesthetics, or biodegradability of bioplastics.
Many everyday disposable items are made of conventional plastics produced from petrochemical feedstocks, such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). These plastics typically perform very well, are lightweight, strong, clear, and inexpensive. However, such conventional plastics have a downside: they degrade very slowly.
Companies innovating in bioplastics will be well aware of the challenges involved in replacing current polymers with bioplastics, a more environmentally-friendly alternative.
Before the world can shift to using bioplastics – and without radical changes in consumer behaviour – these materials must function more like existing plastics.
Finding bioplastics that can perform similarly to, and ultimately replace, conventional plastics inexpensively, is a complex problem, exacerbated by conventional plastics’ principal advantage: their versatility. There will be no one-size-fits-all bioplastics solution.
There are various bioplastics in production today, including:
- Starch blends: readily available and cheap compared to other natural polymers, with good biodegradability. However, poor water resistance and low strength mean starch is typically blended with other polymers.
- Polylactic acid (PLA): made from sugar found in crops like corn and sugar cane, PLA is relatively inexpensive and has several attractive mechanical properties compared to other biodegradable polymers, which makes it popular. However, it is not as easily broken down in the natural environment, requiring industrial composting.
- Polyhydroxyalkanoates (PHAs): made from sugars grown from algae, high production costs are a hurdle to global use.
- Butylene based polymers: include polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT), which are petrochemically-derived, biodegradable plastics.
In the 2022 edition of the Inside Green Innovation: Progress Report, we looked specifically at filing trends in the above types of bioplastics. This time, we take a step back to re-examine the broader trends in bioplastics innovation.
Global patent activity
There is a theory that patent filing trends for a technology area typically go through a double peak before the commercial products really start to make progress in the markets. The data on bioplastics may reflect this phenomenon.
The first peak in global patent filings – in the case of bioplastics, 20 years ago – may well have been built on the early promise of a new technology. Bioplastics’ peak grew through the 1990s before declining by 2015 to half the number of patent applications filed at the peak of 2003. Sometimes early innovation may not fully deliver on the initial commercial promise and filing numbers drop as investment in research and development falls.
However, as the technology starts to gain commercial traction, a second peak emerges in which early movers consolidate their strengths and successes with iterative innovations, while new applicants are attracted by the growing (and validated) commercial success on offer.
As per the theory, another bioplastics peak has started to emerge (Figure 1). The period from 2018 to 2021 (the last year for which there is a complete dataset) shows a significant year-on-year increase in activity. What is striking to note is that 2021 broke the record for the highest number of filings relating to bioplastics, significantly exceeding the previous peak in 2003.
Figure 1: Sixty-year trend (1961-2021) - global priority filings - bioplastic innovations
(Priority filing = the first time a patent application for a unique invention has been filed (the first filing))
Top filing territories
Is it time to celebrate the development of a rich and rapidly growing market for bioplastics that is leading this second wave of innovation, or is there a more nuanced picture?
The split of global patent filings by originating country may suggest the latter, with the new peak showing a significant territorial shift compared to the first peak (Figure 2a). Innovators in Japan almost singlehandedly created the 2003 peak in global bioplastics filings.
Since 2010, however, the number of filings in Japan has slid below that of other jurisdictions such as South Korea, Europe, and the US. Filings from India and China have also grown recently, but at lower levels.
From 2010 to 2012, South Korea was the origin of the most filings relating to bioplastics, but then dropped to be roughly on par with Europe. However, in 2021, South Korea once again accelerated its filings, totalling twice as many as the next most prolific jurisdiction (Europe). This may have resulted from the South Korean government’s announcement in 2020, that it aims to reduce plastic waste in the country by 20 percent by 2025, and that bioplastics would fully replace fossil-based plastics by 2050.
Despite the high number of South Korean-originated filings in 2021, it was still far below Japan’s peak in its heyday, suggesting that the recent global upsurge in activity shown in Figure 1 constitutes the combined efforts of countries around the world.
Figure 2a: Twenty five-year trend - global priority filings by territory - bioplastics innovation
If companies based in South Korea have accelerated innovation in bioplastics purely to respond to incoming national regulations, it is possible that a large proportion of recent filings in the country are paying lip service to innovation in this sector.
This notion seems plausible when looking only at the filings that extend beyond a single jurisdiction (i.e., ‘International patent families’, Figure 2b). In this chart, the dominance of South Korea falls away. It is feasible, but unlikely in this sector, that large well-established companies only intend to service a single market because they see no value for their technology abroad. As such, an element of lip service may be taking place. This may be expected, as government policy promoting/pushing innovation may also come with government and/or shareholder pressure to show innovation.
However, as shown in Figure 2b, South Korea remains the top filing jurisdiction of 2021 for international patent families, and the overall global peak in 2021 remains, with strong filing numbers from the US, Europe, China, and Japan. It is particularly unusual to see high filings of international patent families from China. Therefore, it seems there is a genuine commercially-based global effort to innovate in bioplastics, with an extra burst being seen from South Korea in 2020-2021, possibly due to the provision of a clear government policy.
Figure 2b: Twenty five-year trend - global priority filings by territory, for filings which subsequently extend into other territories - bioplastics innovations
Trends in different types of bioplastics
Is the apparent global push to develop bioplastics technology spread equally among the different types of bioplastics, or are particular bioplastics attracting a larger proportion of research efforts?
The former scenario seems generally favoured, when looking at the filing numbers for starch blends, PLA, PHAs and butylene-based polymers. Filings related to PLA, PHAs and butylene-based polymers all increased by similar rates in 2021, with PLA innovation at a consistently higher level. However, patent filings relating to starch blends dropped slightly in 2021 and its filing numbers were lower than the other three types of bioplastics, suggesting that the poor physical properties of starch blends compared to other bioplastics may be deterring innovation in this area. It will be interesting to see if this is a blip or if the rates of innovation in different types of bioplastics will continue to diverge.
Figure 3: Twenty five-year trend - global priority filings by material - starch blends, PLA, PHAs, and butylene-based polymers
Companies filing bioplastics patents
The sharp increase and high number of filings in South Korea in 2021 are reflected in the data for top filers in the bioplastics sector. The top three filers of patent applications relating to bioplastics in 2021 were LG Chemical group, the Mitsubishi group (in particular, Mitsubishi Chemical Corporation), and the CJ Cheiljedang Corporation. Of these, LG Chemical and CJ Cheiljedang are both based in South Korea, and, unlike Mitsubishi, both filed very few bioplastic patent applications in 2019 and 2020.
The trend is particularly noteworthy for CJ Cheiljedang, which filed no bioplastics-related applications in 2019 or in several other years in the past decade. Furthermore, as the filings by CJ Cheiljedang and LG Chemical account for less than a fifth of the South Korea-originating filings in 2021, it is unlikely that the factors driving these companies to innovate in bioplastics are unique to them.
It seems plausible then that the sudden burst of activity from CJ Cheiljedang and LG Chemical was at least partially in response to the recently announced government policy discussed above. Unless we see a relaxation of policy from the South Korean government, it would not be surprising if South Korean companies continue to be a hotbed of bioplastics innovation in the coming years.
Figure 4: Ten-year trend - top filers (sorted by 2021) – bioplastics innovation
Technology snapshot - 2021
The top filers of 2021 have been focussing on a variety of technology areas, including the four types of bioplastics mentioned above.
LG Chemical has been filing applications that focus mainly on improving the properties of existing classes of bioplastics but has also made filings relating to superabsorbent polymers. For example, LG has filed applications relating to:
- Copolymers of lactones or lactic acid and other hydroxyacids such as 3-hydroxypropionic acid, which aim to have improved thermal and mechanical properties compared to corresponding homopolymers such as polylactic acid (PLA), which can be relatively brittle and heat sensitive.
- Resin compositions comprising blends of bioplastics, such as PLA and polybutylene adipate terephthalate (PBAT) in combination with further components, which could replace traditional plastics such as polyethylene films.
- Biodegradable, superabsorbent polymers, for example, based on polysaccharides such as starch. Superabsorbent polymers can absorb many times their own weight in water and can be used in a variety of applications, such as nappies.
Mitsubishi has generally been focussing on improving the biodegradability of bioplastics.
Certain bioplastics such as PLA and PBAT require industrial composting conditions to fully biodegrade and do not biodegrade effectively in the natural environment, such as seawater. Recent filings have covered:
- The use of bioplastics such as polyhydroxyalkanoates (PHAs), polybutylene succinate (PBS) and butylene succinate copolymers in additive manufacturing having good biodegradability. Conventionally, PLA would be used.
- Blending polyesters such as PHAs or polycaprolactone (PCL) with additional components or modifying the monomer precursors of the polyesters to improve their biodegradability. Such polyesters can be used in shopping bags or food packaging.
- Ethylene-vinyl alcohol (EVOH) resin compositions comprising a conjugated polyene having improved workability, while maintaining thermal stability and biodegradability. Such EVOH-based resins are typically used for food packaging applications because of their transparency and gas barrier properties.
CJ Cheiljedang’s recent filings all relate to PHAs. For example, the filings relate to articles, packaging materials, and multilayer films comprising a PHA.
The rationale behind the filings appears to be about providing plastics with good mechanical and optical properties while being biodegradable in the natural environment, for example, specific types of PHAs and blends of PHAs with other bioplastics such as PBS or PBAT.
Implications for innovation and future patent filings
In the meantime, our data suggests a possible movement toward the type of global action called for by the Organisation for Economic Co-operation and Development (OECD).
The small cross-section above suggests two general directions for innovation in this sector: improving the mechanical properties and appearance of bioplastics to closely mimic the use of conventional plastics; or improving the biodegradability of bioplastics without undergoing industrial composting.
Ideal bioplastics will combine these two often conflicting requirements – a definite challenge for future patent filings (in addition to achieving this at economical cost). We are now seeing progress in numerous categories of bioplastics, such as PLA, PHAs, and butylene-based polymers, although in other categories (such as starch blends) the pace of innovation appears to be slower.
