Polylactic Acid (PLA)- A polydisperse trail of tears.

Many hearts have been broken in the attempt to get PLA on the market. In my case, I bailed from a tenure track asst prof slot to join a startup planning to scale up PLA production. It was quite exciting for a year and then it went belly up. These days, I’m a bit more cautious. I’m not bitter about it. It was a good introduction to polymer science and the marvels of chemical engineering.

In response to a question about PLA, I thought I’d elaborate on it a bit.

I’d be curious to find out more about the PLA experience, particularly the timing.  PLA is certainly a big hit right now.  Natureworks is sold out, and it has also found some niche applications – surgical staples for instance.   

The problem seems to be that if you develop the polymer first and the application second, then you will have a difficult sell.  If you go the other direction, it is an easy sell but you are left with lots of little applications.

Whereas we failed with PLA, Dow Cargill LLC has apparently turned it into an ongoing product called NatureWorks.

In case you haven’t heard, PLA is polylactic acid.  In its most common manifestation, it is the homopolymer of what is designated as the L enantiomer, which is produced from fermentation. Out of respect for my colleagues I won’t name the now defunct startup company.

Most everyone agrees that the marketing appeal of PLA is that it will biodegrade in the environment all the way to carbon dioxide and water, at least in principle. I qualify this assertion because it has been found that this biodegradation requires a fair amount of moisture to progress in a reasonable time. Landfills can be dry, fetid heaps that are not automatically conducive to rapid breakdown of organic materials. At least on the timescale of a few decades.  

In the microbial world, many microorganisms have the enzymatic machinery to biodegrade PLA to lactic acid (LA) and beyond.  LA is a natural compound that is judged to have a benign fate in the environment because it is such a common metabolite. In principle LA could be fully metabolized to CO2 and water once it is depolymerized from the PLA. So went the sales pitch.

In the 1990’s, people were concerned that landfills were rapidly filling to the brim with smelly disposable diapers and plastic junk.  There seems to be less public debate on this today, but I assume that the landfill issue remains largely unresolved.

PLA is made by an esterification reaction called ROP- ring opening polymerization. PLA is not made directly from LA. It is made from the ring opening polymerization of lactide, the cyclodimer of LA. This way there is no evolved water to add reversability to the polymerization.  And lactide is quite reactive.  Initiation of this highly strained monomer can be started with an initiator like an alcohol or an HO-terminated polyether in the presence of a Lewis acid catalyst (tin (II) octoate) in the lactide melt phase.

Lactide can be made by the direct cyclodimerization of lactic acid or by a back-biting reaction of oligomeric PLA made by heating LA.  I don’t know for sure, but I think that the back-biting reaction may be the major route to lactide today.

There is a lot of IP out there covering specialized applications of PLA. Medical and dental implants, sutures, timed released chemotherapy, etc.  PLA will slowly come apart in vivo over time, so it can serve as a kind of scaffold for bone or tissue regrowth or for metered drug release.  But this is a small and specialized market.

The big money is in packaging materials- blown films in particular. However, there are technical challenges here owing to a few of the properties of PLA homopolymer.  PLA has a relatively high Tg, so films will rattle and sharp package corners will crack.  PLA’s crystallinity can be good or bad depending on the application.  PLA also has a tendency to have an amber color and it’s films can block. 

Commodity polymer films have to be dirt cheap. The premium films  are colorless and low haze, have a high gloss, and have a low Tg.  There is a whole industry already producing such premium material from inexpensive feedstocks- the polyolefin industry. Sometimes people parse polystyrene and polyvinyl chloride as industries distinct from polyethylene and polypropylene. Polyethylene, polypropylene, polystyrene, and polyvinyl chloride are the predominant synthetic polymer feedstocks used by the packaging industry. They are well dug into the market with established feedstock supply lines and a global presence. 

Enter PLA.  PLA is ultimately a fermentation product. To get the right tacticity, you need enantiomerically pure LA. The best way to get it is to ferment sugars. LA must be fermented from a carbohydrate source, isolated from the broth (!!), converted to lactide, and polymerized.  Fermentation is a low space yield process. The microbes must be kept alive- excessive LA will kill them owing to low pH. You’ll need a cheap source of carbohydrates.

One of the best sources is corn starch, so a big corn wet mill will be required to produce it. The economics of PLA requires that a producer be vertically integrated from starch to fermentation to monomer production to polymerization. Energy and corn prices will have a large impact on your economics.

I’ll spare you the details going forward. Suffice it to say that PLA can’t compete with polyolefins on a price per pound basis at the present time.   PLA is boutique polymer at best for the forseeable future. My former company, the defunct PLA startup, felt that the best market segment for PLA was the market occupied by nylon films, due to the comparable cost and food contact and barrier properties. I have no idea what the economics look like now, 10 years later.

I wish all of the players well in the PLA business. It is a worthwhile endeavor and I wish that my experience had turned out differently. So it goes.

For an updated post on PLA, follow this link.

     

 

 

About these ads

About gaussling

Gaussling is a senior scientist in the chemical business. He occasionally breaks glassware and has been known to generate new forms of hazmats. Gaussling also digs aerospace, geology, and community theatre. View all posts by gaussling

49 responses to “Polylactic Acid (PLA)- A polydisperse trail of tears.

  • Vlad

    Hello!
    A couple of weeks ago, me and a friend of mine, both students at a university in Romania, have decided to innitiate a project on PLA wich, if viable, would be funded by certain american and european companies, in colaboration with the Romanian Government. In my country, a great amount of time and money have been spent by the Government on campaigns to support “green industries”, although I personnally feel that the effects of these crusades are yet to be expected. Massively poluting industries have been dissolved, but no alternative solutins have been, at least specified, yet implemented. A very large number of highly-qualified people have become unemployed, due to the massive closing of chemical factories. You can immagine that the population did not approve of these environmental-friendly measures, noble in fact, but so brutally applied. This is why we thought that a PLA production plant could replace the dead PET industry. After a lot of personal research, I’ve also concluded that this could also be a salvation for all the farmers in the neighbouring areas, who have no costumers for their grains, and would be more than satisfied to sell all their products at an acceptable price. Now the big question is: “Wolud I be able to sell my products?”… Is there a market for the PLA products? All we have to do for our project to become feasible is to find companies that would make use of our PLA-based products.

  • gaussling

    Hi Vlad,

    Others might disagree, but I would characterize PLA as a “boutique” polymer. It is made by a very few companies and has not seen widespread adoption in the market. Getting a new polymer product to market is very difficult. The market is approximately saturated with PET, polyolefins, rayon, nylons, various rubbers, and specialty polymers like perfluoroethylenes, kevlar, etc. So, bringing in another polymer to the mix pretty much means taking market share from established products.

    In the case of PLA, its adoption usually requires that a user to make a change of some sort. If polyethylene is working fine for them, and it is inexpensive, why should they change? If your proposed replacement polymer (i.e., PLA) is less expensive and requires no alterations in the end users practices, then getting them to adopt PLA would be relatively easy. However, if PLA costs twice as much as their current material, or if the PLA requires some alteration in their practices, then adoption will be difficult or impossible for the customer to justify.

    As a replacement for PET, PLA might have some problems. PLA might not be as hydrolytically stable, or there might be regulatory problems for food contact applications. I have purchased water from PLA bottles here in the USA, but I do not know what the constraints for food packaging might be.

    One of the best applications for PLA that I was aware of was for non-woven fabric applications- “geo-tarps”, landscaping fabrics, and diapers. PLA evidently spins a fiber that makes a good non-woven fabric. I have been out of the field for a few years now, so the thinking might have changed.

    You will have to dig deep to find a market for PLA in your area. Find out what people are paying for competing polymers and then decide if you can make/use PLA at a profit. If you are going to make PLA, you must have a source of carbohydrates for the fermentation of lactic acid.

    Manufacturing of PLA products goes like this- agricultural production of starch => fermentation of starch to lactate => isolation of purified lactate => preparation of lactide => polymerization of lactide to PLA pellets => manufacture of finished goods by extrusion of films, etc. In the USA at least, the economics required that the manufacturer be vertically integrated from corn starch through extrusion in order to have any hope of making money.

    I’m not sure if this helps. But good luck.

    Th’ Gaussling

  • erkut aratay

    hı,ı am erkut from turkey,ı wonder pla products very much.ıf you gıve me more ınfo about pla ı am very happy, best regards

  • Michael Bower

    While the original author seems to have some knowledge of PLA he apparently has no knowledge of the commercial applications. My Company Plastic Suppliers has been selling Millions of Pounds of this material under the EarthFirst Brand Name. Applications range the gamit of the packaging market and Walmart is one of our largest users.

    Speaking of Blown Film my company has been doing this for quite awhile and we should be receiving our patent on the process soon. Medical Applications are old history. This material is bumping up against supply issues because it CAN compete with the commodity plastics.

    I welcome you to visit our website at http://www.EarthFirstPLA.com or e-mail if you wish to learn somemore about this fascinating material.

    Michael J Bower
    Director of R&D
    Plastic Suppliers
    bower@plasticsuppliers.com

  • gaussling

    Hi Michael, Nice to hear that you are having a positive business experience with PLA. I have no doubt that it is increasing in market share and I am glad to hear that it is being adopted by Wal-Mart in some fashion. I should reiterate that my experience was on the manufacturing side of PLA, not the converting side, so of course my knowledge of current commercial applications is not on par with yours.

    This post was really a cautionary tale about introducing a new polymer to the market. You are a converter of PLA, not a manufacturer of it, so your whole perspective of the business is a little bit different. A manufacturer of PLA has to win over the converters, who have to win over the consumers. Unless the converters are working to convince the Wal-Marts of the world that they need to switch to PLA based products and can do so for no change in price, there is no market upon which the manufacturers can propose developing technology packages to build plants. It is a chicken or egg problem. And that’s where we were 10 years ago with PLA. The converters, the customers of the manufacturers, had no real demand for PLA because existing markets used cheaper polymers. One other point, when I was in PLA, it was not yet a commercial product, so there was no real price point to aim for- just estimates.

    I have been in the polymer field since I left PLA so I’m not completely out of touch. It is hard to beat the economics of ethylene and a Ziegler-Natta catalyst, or phosgene and bisphenol A. I know “millions of pounds” sounds like a lot of mass, but a single polyethylene train can put out 80,000 + pounds per hour 24/7- that’s 13.44 million pounds per week for a single train. This is the kind of commodity scale that PLA is really competing with and that was my point. PLA is still a boutique product in the market place and has the pluses and minuses therein.

    I’m very glad to hear from you and to learn that PLA products are moving well.

  • Jose

    Hello

    My name is Jose. I’m a professor at the Universidad del Valle in Cali-Colombia. Now I’m working in Mexico with byodegradable polymers and we need polylactic acid type L with high molecular weight (maybe 120000g/mol).

    Could you helpme with information about where can I buy it.

    thanks for your help.
    Ing. Jose.

  • sang

    Hi Gaussling,
    My name is Sang. My company is looking for a vendor of PLA. Can you help me with this. I try to look all over the place with Nature Work LLC. Walmart book all their capacity. Thanks for your time.

  • gaussling

    Hi Sang,

    Have you tried asking Cargill? They are the manufacturer and should be able to name a distributor. Best of luck.

  • nagu

    hi,i am nagu.i working on pla.any one knows how to calculate the isotropic refractive index of plla.plz give me the detail calculation.

  • Lucía

    One of the main issue right not in the PLA market is that there is only one functional producer, NatureWorks, with shortages in capacity. This means that demand is higher than production at the moment, which is not a bad situation for PLA producers. Despite NatureWorks being the only one commercialising it right now, there are many companies considering to enter the market, which would be highly appreciated by most end users.
    It is obviouly a small market in comparison with commodity plastics, but i don’t think the strategy is to directly compete with them. Bioplastics in general have to be sold as a higher quality product with a clear added value, it’s the only way to justify the higher price.
    PLA, it has to be said, is not the only alternative, there are other materials out there, and it is an explosive market right now, as applications multiply and the biobased content becomes more sellable.

  • gaussling

    Hi Lucia, You have touched on the title- “Trail of Tears”. A few other companies have tried to get PLA on the market and have failed. I am in the polymer business and we supply products to polymer producers. It is diffiuclt and risky for even the biggest players to get a their version of an existing polymer on the market, much less a
    “new” polymer like PLA. BAsically, PLA has to compete as a replacement for PET, PVC, and PE for the packaging market.

    There are IP problems too. A new producer of PLA will have to find a technology package that has good economics. It took the combined resources of Dow and Cargill to get PLA going- polymer technology and starch-based lactic acid supply to get the value chain loked up. Our studies in PLA processing showed that a manufacturer had to be vertically integrated in momoner manufacture to make it pay.

  • Luisa

    Hi, I’m doing a project about the proccess production of PLA. Somebody can send some information about this?

  • Raul Raudsepp

    Hello PLA-comapnions!

    The estimations and comments about of the PLA situation of gaussling is impressive. And by my point of view quite correct too.

    Without of workouts of the end-products is nearly 0 possibilities to have breakthrough(s) into the markets.

    By the reason we was starting at the end of.

    If someone interested about, do’nt hestitate to visit a web-site of ours: http://www.nordbiochem.eu. There is little bit about of our activities to ferment the LA and processing them to different derivatives (used as solvents etc). We have PLA solutions too.

  • tunsdJ

    Hi everybody,

    I am quite impressed by the quality of the exhanges. Thank you very much Gaussling for all your efforts. I agree with most of your point except that I consider that providing a green product to the end market may weigh in the balance of some managers even at a little bit higher price.

    I also wld like to raise the long term issue of PLA : it is using agricultural material to be created, right ? Scaling up production would end up in an increasing use of water resources to grow and crop, say, corn. Is this really environmentally friendly ?

    Finally I would like to know if someone knows why there is only Dow Cargill in the market, and when there patent expires.

  • gaussling

    To answer the last question first, my former company tried very hard to be in the business first. Technical trouble along with uncertain demand and shallow pockets prevented our entry. I think that the main reason that Dow Cargill is the major player today is that they could throw sums of money at their market entry over a fairly long time period. Both Dow and Cargill bring strong fundamentals to the table. Both are well integrated into their respective markets and both are quite profitable. Dow brings extensive polymer experience and Cargill brings a solid position in the feedstock base. Both were determined enough to wait out the time needed to take market share from other polymers they replaced.

    Regarding the long term use of PLA, the main feedstock is/was corn starch. Enantiomerically enriched lactic acid is required, so fermentation is used to deliver the required low cost monomer. Perhaps there is a possibility in cellulosic lactic acid? I don’t know. The economics of starch extraction and lactate fermentation are going to be greatly perturbed by ethanol production.

    The draw of PLA is it’s use wherever biodegradability is perceived as valuable. Food contact and geo-fabrics, etc., are commonly cited examples of PLA market growth.

  • vhinz

    where can i get a graphical representation of supply and demand for bioplastics (PLA) and conventional plastic in the world market?

  • Jarrod Hart

    It looks like PLA is getting some attention now – front page of a major UK weekend paper – and unfortunately negative – it is the problem pointed out right near the top of the article – the degradation in landfill conditions. Interestingly, it is not the question of whether it will degrade, but whether methane will be released (global warming no-no). They are also highlighting that PLA will be hard to keep out of recycling streams, where it will cause trouble.

    Do you think these a) are valid issues, b) will they be show stoppers?

    Thx for a interesting article!

  • gaussling

    Hi Jarrod,

    PLA is supposed to hydrolyze to lactic acid, which should biodegrade to CO2 and water. In a landfill environment, O2 may be deficient and anaerobic fermentation may consume lactate. Whether it goes to CO2 or methane is unclear to me. Perhaps a microbiologist can comment on the anaerobic fate of lactate.

    In regard to the possible contribution of PLA to atmospheric CO2 via fermentation, society has to make a calculation about where it wants its waste products to go. I’m not convinced yet that global warming is entirely anthropogenic. It is certainly happening, but is CO2 a cause or an effect of warming? Does it lead or lag warming? So the merits/problems ratio of PLA => CO2 is hard to address.

    Unfortunately, the biodegradation of PLA will be accompanied by sloughed off package labels, adhesives, bottle caps made of other compositions, pigments, plasticizers, and catalyst and initiator residues. So it won’t be squeeky clean under even the best conditions.

    I am a proponent of recycling and cogeneration. Cogeneration uses fuels to generate working steam and electricity. The steam can provide space heating, pressure, and industrial process heat. The electricity can be wired to where it is needed.

    Molten polymers are subject to phase separation in the same way oil and water are. PLA is a polyester and as a result, is somewhat polar. When incompatible polymers are co-melted, they can form multiple phases that can freeze into a fruitcake composition of poorly mixed polymers. It may have very poor physical properties- or just have a bad appearance- and as a result would not be saleable. This is why it is critical to sort polymers prior to remelting and reuse.

    PLA poses no extra problems. It is yet one more polymer to sort.

  • gaussling

    vhinz-

    “where can i get a graphical representation of supply and demand for bioplastics (PLA) and conventional plastic in the world market?”

    Gosh. I don’t know. I’m no longer in the PLA world. Sorry.

  • Raul Raudsepp

    vhinz-

    at the bioplastic24.com site. They have (not full) report of.

  • Greg Zaller

    Perhaps you could give me some idea of amount of fossil fuels going into producing this cup from the farm to the supplier. It appears that only part of the corn is used as well as energy intensive manufacturing. My suspicion is that twice the fossil fuel ultimately goes into PLA cups compared to a styrofoam. Even if possibly these cups are more efficient than styrofoam we should also include the sustainability of farming along with the claims of it being a “green” solution. I am trying to find out.

  • Greg Zaller

    A PLA cup weighs 12 gm and an equivalent styrofoam cup weighs 3 gm. This is a difference of 4 times the raw materials which cost about the same energy per unit weight to produce including both manufacturing and production costs. In the USA we loose an average of 20 tons of top soil for every acre of corn. We are better off to sequester carbon into land fills than to release it to the atmosphere regardless of whether this is by burning or composting. How much humus does a composted cup turn into?

  • pierre régardaud

    Despite PLA seems to have a great commercial future, Cargill is still the only producer of PLA today ? Strange isn’t it ?

  • gaussling

    I guess I’ll have to say that the expense of getting a specialty polymer to commodity scale is a huge disincentive. Given that PLA products would have to replace cheaper materials right from the start, the demand picture is not very encouraging. Cargill and Dow have the vertical integration and market position to usher a new polymer onto the market and withstand poor profits for the needed time for acceptance.

    Greg Zallers point above is a very good one. I am not aware of foamed PLA, so the cost benefits of a rigid foam are not available to PLA products. Polystyrene is hard to beat.

  • pierre régardaud

    Maybe the commercial success of PLA is linked to the unavoidable increase of petrol price. But this process could be very long.

  • Ted Pitzen

    Hello,
    I have a customer looking to use PLA in emulsions, typically soap based, for wax applications. Volumes are large, but I have no working knowledge of PLA. I am not a chemist, but understand some of the basics.
    The customer doesn’t know much about PLA’s either but is looking to test for a possible fit.

    How would PLA be used or what would be the benefit, other than being able to use “green” verbage, a blender/compounder would see from using PLA as an ingredient in emulsions?
    I work with Cargill/Elevance on soy waxes, but the PLA side is new to me.
    Can you explain what are the benefits provided by PLA when used with waxes, either petroleum, natural or synthetic (Alpha Olefins)…
    Thanks.
    Ted

  • gaussling

    Hi Ted,

    What attribute does the customer think PLA will provide? PLA- a fairly high MW, high Tg polyester macromolecule? If the customer wants an association with PLA for marketing purposes, what about PLA packaging?

    PLA oligomers can form emulsions. We ran into this in our Lactide direct cyclization process. Emulsions with L1 thru ~L20 lactic acid oligomers were formed with the aromatic process solvent.

    I am unaware of any benefits that PLA might provide to wax formulations. But please do not consider me an authority on such formulations.

    Lactic acid is used in various formulations to adjust acidity. It sounds to me like this is a science project involving the preparation and formulation with various MW’s of PLA. Perhaps PLA has some useful attribute in the wax field. But I am unaware of it.

  • Johan Lundin

    Hi Gents, thank you for an enlightening article. I am evaluating the environmental impact of PLA bottles vs. PET. PLA has some obvious advantages but there are some questions left unanswered, namely water and fertilizer (green house gas contributor) use to grow the corn. I know that both are substantial but I have no estimates. Do you have any such figures?
    Also, do you know how many lb of corn it takes to make one lb of PLA resin?
    Thank You for a great article!
    Cheers

  • gaussling

    Hi Johan,

    I’m very sorry. I do not have such numbers for you. I have been out of the PLA business for a decade, so I’m really out of it.

  • Wade

    Gaussling, thanks for the informative article!

    I’ve been experimenting with running a rapid prototyper (a RepRap Darwin) on ABS plastic, and am having issues with warping of the finished product, as well as problems with the volatile compounds that off gas during the ABS extrusion process.

    Apparently PLA has been working relatively well in some experiments in the UK and NZ; PLA seems to build good parts with little warping. Details here: http://hydraraptor.blogspot.com/2009/08/more-playing.html

    Do you know if there would be any harmful chemicals released during the extrusion process? I would guess not, but I’m no chemist. I’m also looking for a North American supplier for small quantities of PLA, ~5 kg batches in 3mm diameter filament would be ideal; just curious if you might know of any.

    Thanks!

  • gaussling

    Hi Wade, I’m guessing that the cutting tool may have enough localized heating that it may be depolymerizing the ABS. Polystyrenes do this and you can smell the styrene gassing off. Is it possible to play a stream of air or water on the cutting tool for cooling?

    I do not know for sure, but PLA may have a similar problem- though lactic acid momomer is a high boiler, if you are too exuberant it might depolymerize and dehydrate to acrylic acid, which is a nasty lacrymator. You’ll know if that is happening- get some ventilation. Just exercise some caution and keep the part cool. That might help the warping problem too.

  • Wade

    Actually, instead of cutting blocks of plastic with a cutting tool, we are feeding in ABS or PLA filament into a small heater, melting it, and extruding it through a 0.5 mm diameter hole, and using that to build up our objects. Details at http://www.reprap.org.

    The melt chamber runs at 240 deg C for ABS, and I hear 190 deg C works well for PLA. We need fairly high temperatures to get good bonding between the various layers.

    At what temperature would PLA start to depolymerize? I suppose I’ll just have to try it and see – as you say, it should be pretty obvious. A trail of tears indeed! :) Thanks.

  • Ignacio Medrano Carmody

    My name Ignacio Medrano Carmody, and as a Industrial Engineering student of the UNS (Bahia Blanca, Buenos Aires, Argentina), I am researching about bioplastics. This research it’s the most important task of the last subject of my university programme: “Evaluación y preparación de proyectos de inversión” (Investment project preparation and evaluation) in which I found this interesting and challenging industry.
    In this context, we need some information for academic use about the process of the bio plastic production.

    We found this flow diagram (the one I have attached), but for the propose of evaluate the amount of the investment, we need at least the estimated price of the machinery involved in the process (equipment), for example: Reactors, distillation tower and any other equipment that the process may need.

    Off course I understand that there is certain information about the know how that you must keep indoors, but I ask for your help in order to develop our project and of course to be kept inside the UNS, I only need to know which equipment is involved and an estimated amount of the prices of this machinery so I can have an idea of the relevance of the investment.

    In addition,and not only to ask for help. I offer my help in case you may need something from my country, cause we have researched a lot and we found out some interesting opportunity to develop this industry in our country, specially in our province.

    Thank you very much for your attention and hoping to receive news from you.

    Regards

    Ignacio Medrano Carmody

    UNS

    Argentina

    PS: If you need a copy of my project I can provide it. And while we were studying this research we came up with the idea of an alternative of changing our objective to only buy the bioplastic pellets and with them munufacture the plastic bags or different products to make this project more simple and detailed.

    • gaussling

      Hi Ignacio,

      Wow. You have a big project ahead of you. I assume you are referring to polylactic acid. I was not involved in the economic studies so I cannot offer concrete examples of equipment and costs. Let me say this: our PLA process started with a corn wet mill that produced corn steep which we used as a growth medium for the microorganisms that fermented starch into lactate. This is a low space yielding process- as the fermentation proceeds, the byproduct lactic acid would lower the pH, requiring that the medium have some buffering capacity. To remove the lactate from the aqueous broth, we used an electrochemical membrane to selectively migrate the lactate across the membrane. The power required to do this was a problem cost-wise.

      Once we had the lactic acid concentrated to ca 85 %, we used a proprietary process to directly dimerize lactic acid to L-lactide. This was unusual. Most approaches involved oligomerization of the lactic acid followed by thermal backbiting of the oligomers to produce lactide under reduced presure. The lactide was collected and then submitted to polymerization with suitable catalysts and initiators. Tin octoate is commonly reported as a ROP catalyst and a high boiling primary alcohol is used to initiate the ROP. Polymerization can be performed in an extruder. It’s called reactive extrusion.

      It is critical that acid levels in the lactide be below some critical value otherwise the process will produce low MW, off-colored polymer. Ideally, the polymer should be water white. It can easily turn amber under less than ideal conditions. This acid issue is so critical that it shut our company down and tossed us on the streets looking for work. Bummer.

      Hope this helps a little bit.

  • Clarissa Audrey

    Hi! I’m doing a study on the PLA manufacturing process. What are the various equipment used in the polymerization process? Is NatureWorks (Cargill) the only one who manufactures PLA? Is corn the only feedstock they use?

    Thank you in advance, I would really appreciate the help.

    • gaussling

      Hi Clarissa,

      One of the best places to look for process specifics is the patent office.

      In regard to DowCargill, I am familiar with their process only in broad strokes. My understanding is that they do backbiting to produce lactide from lactic ester oligomers and it is probably done under vacuum. I can only presume that they use reactive extrusion to produce polymer.

      I presume that they blow PLA films with annular extruders, but I could be wrong.

      Corn processing is something that Cargill has lots of experience with. Biomaterials like starch are what Cargill brings to the table in PLA mfg. Dow is a colossus in polymer processing. Together they were able to bring PLA to market.

      I would advise a study of the patent literature and whatever may be in trade publications regarding the technology. I’m not much help.

  • farid Rouhi

    HI, our company is thinking of investing on a PLA production plant with 20,000 ton/year capacity. As far as I know this will cost about 40 to 50 million U.S.D. My question is can we be sure that our product will sale intenationally with no peoblem? I mean can we hope to work 24/7 full capacity?
    Thank you

    • gaussling

      Hi Farid,

      A lot depends on your unit price of PLA pellets. PLA will be competing with other polymers for packaging and container applications. If you cannot supply a cost advantage, then you must at least reach cost parity with the product you wish to compete against. End users of PLA want to be seen as green, but they do not wish to lose market share or pay extra for it because of it.

      The customers who matter most in my estimation are not the end users of the PLA product. The critical customers are the converters who take the pellets and mold parts or films from it. They are tied in to the end users far more than the PLA makers. The converters want drop in compatibility and no cost premium. And they want to retain the same productivity from their equipment on a switch to PLA.

      So, to answer your question, you must commit some resources to understand your direct customers needs. These people are the converters. They’ll tell you a lot about the market place. If there is latent demand for PLA, the converters should know about it. Also, pay attention to the issues surrounding food contact applications. This is a very important market.

      The marketing of PLA is a game of stealing market share from established commoditized products like polyesters and nylon and polyolefins. You must have a deep understanding of the marketplace before you jump into a specialty polymer like PLA.

  • Dulce M. Flores

    Hi clarissa audrey,
    my lab is here in the Philippines and am working on sago starch as a starting raw material for L(+)lactic acid production. As to your question I assure you any starch other than corn can be used, although most LAB can only convert the feed glucose hydrolyzed from starch by a separate step. Sago starch is in abundance in this part of Asia and I am now in the process of a patent application a direct one-step one-inoculum process of producing this specific enantiomer from sago starch, which has shown about 80% starch conversion efficienccy at 30C, or ambient temp in our region.
    Dulce M. Flores, PhD
    Professor, University of the Philippines

  • Tim Dunn

    All posters seem to take it for granted that making plastic out of corn is a good thing. With over a billion people hungry, it seems like a very bad thing to me. Add in the effects of making fuel out of food, and it looks even worse. Conventional plastics are made out of byproducts of gasoline and diesel production. Most of this byproduct would be burned off it it weren’t being made into plastic. So, Cargill et al as us to make diesel, throw away the byproduct, use the diesel to grow corn, and the result is a weak, expensive plastic that threatens the world’s poorest people with starvation. What’s good about this? You can make biodegradable plastics out of petroleum byproducts, you know.

    • Secret

      In response the the above statement.

      Corn is extremely easy and efficient to grow and re-produce. Most PLA manufactures are now growing their own Corn and not bighting into existing crops…. I can aggree with you being concerned about the hungry, but that has nothing to do with the production of PLA.

      I run a compnay that is in the process of establishing a PLA Plant that will run of Wind, Solar and Biofuels derived from Sugar Cane.

      PLA is the way of the future. Oil based plastics is old fashioned and on the way out!

  • Secret

    The Global Economy within 30 years will be dictated by the youth of today.

    The younger society is much more environmentally aware and conscious, PLUS they are willing to pay a premium for Green Goods.

    PLA all the way!

  • Frito-Lay’s New PLA Rattle Bag « Lamentations on Chemistry

    [...] this link for an earlier post on this topic. Possibly related posts: (automatically generated)Fashion Show [...]

  • B. Lucken

    I am looking for a few bits of technical detail on PLAs.
    1. What plasticizers are used in the PLA compounding and in what loading levels?
    2. What is the current mkt pricing for PLA? Have they hit $1.50 yet?
    3. Other than Polyone, who is a big PLA compounder?
    4. Other than NatureWorks, are there any other significant PLA producers?
    5. Who makes PLA based Food packaging, nonwovens, films, etc. – in other words, who are the big converters (if any)?

  • udellhuynh

    dimming america direct current actual [url=http://www.geolsoc.org.uk]power radiation[/url] http://www.mbmg.mtech.edu

  • Ralph Furley

    I found this page to be an interesting read. A lot has changed since 2007 when the author first wrote this. PLA is finding increased usage in the last couple of years as feedstock for 3d printers. It’s preferred by many over its main rival in this market, ABS due to its ease of printing, the high detail attainable through PLA prints, and the relatively lower heat required both to extruxe the material and to affix it securely to the print bed. I see 3d printing causing an exponential demand for PLA in the next few years.

  • golden labrador

    Fine way of telling, and good paragraph to obtain information concerning my presentation focus,
    which i am going to deliver in university.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 97 other followers

%d bloggers like this: