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It's a Cap. It's a Toy. It's FUNCAP and it shows that the circular economy can be made super-elliptical.

Photo of Soren null
28 21

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Approximately 19 Billion LEGO components are produced every year. LEGO bricks are one of those things that never break and most people pass them down from generation to generation. Why? Because they're of great quality and fun to play with!

Every year, 200 billions of plastic bottles are used for water but only a fraction of the caps are recycled. Why? Because they are pretty much useless after the bottles have been emptied. What if they weren't?

Maybe if the caps could also be used for something else fewer might end up being tossed away! 


Our proposal to get rid of plastic caps becoming garbage and polluting the environment is to design them to seamlessly work as a LEGO component after the early retirement from their bottle sealing careers. 

Thereby, the life cycle goes from 10 minutes of usage (while drinking from the bottle) or 1 year (the usual shelf life of bottled water) to years and even generations of play-time with the toy. (A fun fact: The LEGO bricks used in the photos are around 40 years old. The plastic screw caps are around 1 months old.)

Some call this approach "upcycling". We coined the term: The Superelliptic Economy!


FUNCAP combines the desired properties of a plastic screw cap (such as tight seal, easy to press down on the threaded bottle neck on the filling production line, easy to open by hand) with the properties of a LEGO brick (such as high quality, fine tolerances and perfect mechanical connectivity with other LEGO bricks).

FUNCAP is made in different shapes and sizes. However, a round shape facilitates its introduction in existing bottle filling production lines. Plastic screw caps come in different diameters (e.g. 38mm, 35mm and 28mm). As the most commonly used plastic screw cap size is 28mm, a 4x4 knob LEGO brick (31.8mm width) provides a good starting point for the first FUNCAP.  

FUNCAP is a keeper

Currently, there are more than 80 pieces of LEGO bricks in existence per person on planet Earth, and there are LEGO fans (of all ages) everywhere! 

It is therefore very likely that avid LEGO builders (and their relatives) will see the benefit in actively collecting FUNCAPs and adding them to their brick collection. 

As Trevor and Benjamin, young parents in Minneapolis, USA, said to us sometime in the future (sic!), probably around June 2018, about their two kids:

"They collect the FUNCAPs – not only from their own bottles, they also collect FUNCAPs from others."

high Social Return on Investment (SROI)

Other than being an obvious immediate benefit to the kids that love to play with LEGO, the economical benefits of FUNCAP, despite a (likely) increased unit cost, are obvious as it combines the utility of the screw cap and the LEGO brick.  

Both caps, as well as LEGO bricks, have some initial costs associated with manufacturing. However, the plastic screw cap only creates value for a limited period of time. All components have eventually a disposal cost (not shown). The quantitative value of the long-term benefits of stimulating learning is difficult to estimate - but the "Net Present Utility" is positive.  


Four things are needed to make FUNCAP happen:

  • Scale (in order to reach a reasonable unit cost level)
  • Reach (distribution of FUNCAP)
  • Materials (choose the right materials properties to do the job) 
  • Innovation (access to Intellectual Property Rights in combination with the willingness to try something new and bold)

The table shows some Plastic Screw Cap solutions (as well as the pure LEGO brick):

The "Perma Cap" (which comes in many shapes and forms - 'many patents, no products') initially looks great (and reminds of the  stay-on tab for aluminium cans). However, it is often necessary to separate the screw cap (made of HDPE or PP) from the bottle (made of PET) in order to recycle both. The initial benefits become, when looking at the total supply circle, a huge disadvantage. 

The idea of turning bottle caps into LEGO bricks is not new. A Brazilian company introduced "Clever Cap" to the market but the product has no presence or traction. It seems that none of the Value Barriers were properly addressed. 

The materials selection for FUNCAP is "TBD" (To Be Decided). The decision on which materials to use is not a trivial one (and is a value barrier). However, what is clear is that by combining two functions into one, a lot of plastics is saved. In this case from 9 gram to 5 gram or a reduction of 44%!

VALUE BARRIER: Reach and Scale

If you have Reach, you can Scale your production and thereby enabling economies of scale for lower production costs as well as broader and faster adoption globally. 

The global bottled water market is estimated to grow by 8.5% and reach a value of $ 280 Billion by 2020.

As it happens, the key players in the global bottled water industry include Coca-Cola Co., PepsiCo Inc. and Groupe Danone. All of these companies are participants in The New Plastics Economy Initiative. All companies have Reach. All companies can Scale. 

As Emmanuel Faber, CEO of Groupe Danone, states in his 2017 endorsement of the Initiative: 

"Resources management should not be summarized as a matter of cost optimization but as a powerful driver of shared value creation. [...] I am excited that Danone is taking a leading role in this initiative to help drive systemic change."

"Cost Optimization" deals with Year 1 in the Net Present Utility" graphs already mentioned. "Value creation" is related to the Net Present Utility. Consequently, FUNCAP is fully aligned with the mindset of (at least) one of the leading players in the bottled water industry.


LEGO bricks are made of ABS plastics whereas a plastic screw cap is made of HDPE (or sometimes PP) plastics. Sometimes, an additional material is in-molded into the cap as a gasket. It is not obvious that ABS can be substituted by HDPE or visa versa. New materials could also be explored depending on desired lifespan for the FUNCAP to serve as a play piece. 

Fortunately, the LEGO Group has allocated substantial resources to materials development: In 2015, the LEGO Group established LEGO Sustainable Materials Centre in a significant step up on the 2030 ambition of finding and implementing sustainable alternatives to current materials. LEGO Group owner Kjeld Kirk Kristiansen says:

"The investment announced is a testament to our continued ambition to leave a positive impact on the planet, which future generations will inherit. It is certainly in line with the mission of the LEGO Group and in line with the motto of my grandfather and founder of the LEGO Group, Ole Kirk Kristiansen: Only the best is good enough”.

If the cost price constraints on screw caps for bottled water is loosened, it is likely (assuming that appropriate economic and human resources are allocated) that a suitable material for both bricks and caps can be identified.

VALUE BARRIER: Intellectual Property RIGHTS (IPR)

Rather than using (inferior) designs that might infringe on LEGO's intellectual property (and thereby limiting the reach of them), we propose to do FUNCAP in cooperation and understanding with LEGO and the bottled water manufacturers. 



Music: Enthusiast by Tours             



How does this Idea redesign unrecyclable small format plastic items that often end up as waste?

FUNCAP combines the short-term value of sealing a bottle with the long-term value of building with LEGO.

Which use cases does your Idea apply to?

We let Trevor & Benjamin (young parents in Minneapolis, MN, USA), speak for us (sometime in June 2018): “We love taking the kids out to the park during weekends. We almost always bring something to drink. Since Danone introduced the FUNCAP, our kids ask for us to bring bottled water only! They collect FUNCAPs – not only from their own bottles, they also collect FUNCAPs from others."

How do you envision scaling up your Idea?

Sometimes, very little has to be invented. Things just have to be combined in a new way. The successful implementation of a Superellipitical Economy Thinking (example: FUNCAP) requires that different companies work together "for the greater good". The world of business does not work like that. Getting existing market leaders to work together is the only way to create a real impact. (Even the spell checker suggests that we change 'Super-elliptical' to 'Surrealistically'!)

At what stage of development is your Idea?

  • Research & Early Testing: You are exploring an idea, gathering inspiration and information needed to test it with real users.

Please describe how becoming a Top Idea and working with the Think Beyond Plastics Accelerator Program will help to accelerate your solution.

Is FUNCAP possible? Yes! But only if the value barriers are overcome. Not by Hans and Soren but by the leading companies in the industries of toy building blocks and bottled water. Can Hans and Soren forge a strategic alliance between LEGO and Danone? Probably not. Can The New Plastics Economy Initiative, Ellen MacArthur Foundation, International Sustainability Unit and Wendy Schmidt do it? We hope so. "Only the best are good enough."

Please describe from where your Idea emerged

FUNCAP is one idea (among around a dozen) on how to demonstrate the Superelliptical Economy by combining different potential uses into one component.

Tell us about your work experience

Hans is Swedish and currently works for an automotive company in Sweden. Soren is Danish and lives in Brazil. He develops businesses and products.

Please describe your legal and organizational structure

Limited company.


Join the conversation:

Photo of Alan Somerfield

Hi guys,

Have you seen Parein Caps and Cups ?

Photo of Soren null

Alan Somerfield Thanks for the link! Never heard about that concept. The idea of interlocking lids is not new, and this particular design has some design flaws (some of them are probably show stoppers for implementation). Just a few here: The external hinges will cause problems in a conventional filling line; the caps are not compatible with LEGO (which will limit the fun and probably make it a single use/"few uses" item); it looks like that it's difficult for kids to assemble the units; the cap seems significantly higher than a normal cap (i.e. significantly more material is used) and will require the external packaging to be changed. We may be wrong. However, it seems that that particular concept was never bought to market so we're probably not completely wrong... Anyway, good luck to the inventor.

Photo of Eric Parein

Hans & Soren, congratulations on you FUNCUP-LEGO approach. I myself went deeper into the matter; my cap is the stud on the LEGO-block. So, as my cap is an essential part of the LEGO-brick, my cap can simulate all LEGO-builds (those without their many accessories). Then, as the studs are round, my cap can build in any direction! LEGO can only build under four 90° directions. Important, my system is a 'One-Block'- (toy) building system; use your imagination and creativity to bring your art! Check my video's and PPP on 'PAREIN Caps and Cups'.
Flow n°1: The external hinges do not cause problem in an appropriate designed (adapted) filling line; the top part of the PAREIN-cap has no hinges. BTW, all over feasibility is proven at the 'highest level' (has 1400+ fillers). They are waiting for the first of their Fillers to dare, 'Then the rest will fallow!' dixit R&D Chief.
Flow n°2: As above, PAREIN-caps is (!) LEGO. Only much bigger, and... for free!
Flow n°3: Kids love it, because they perfectly can handle it, no frustrations. Check video on
Flow n°4: The PAREIN-cap is not higher on the bottle; the tread is in the upper part! No changes whatsoever to the external packaging.
Flow n°5: Indeed, more material is used, only to suit the many toy-requirements! Remember, PAREIN is a TOY only temporarily serving as a closure or FMCG portion cup! The PAREIN-TOY remains there as long as LEGO-elements do last...
Gentlemen, 'was never bought to market'? As I stated before on my entry file 'PAREIN Caps and Cups', revolutions are hard to start up, but once it has started there is no holding back! Remember the (sea-)container? Nobody (of the Unions) believed in it, WANTED to believe in it! Check my folding container design on Yes, also a revolution, yet CONTICKE(tm) is the most downloaded file on my SlideShare page! Not by kids!
Believing is Receiving! Kind regards, Eric

Photo of Soren null

Thanks for your feedback Eric and good luck!
We also believe (obviously) in the idea of turning the caps into toys and that "revolution" is yet to come :-)

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