Brent Borgerson
Brent has been a Senior Process Engineer at Matrix Tooling for 12 years. With 43 years of Injection Molding experience Brent excels at maintaining and debugging even the most difficult of molds. He started his career at Triton College, and the University of Montana.
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Matrix Plastic Products has been micromolding plastic parts since the mid-1990's, long before it was in vogue. This pusher (shown) for a micro linear cutter cartridge is .031" x .040" x .040" and weighs just .0008 grams. Most of our micro projects are for the medical industry, for minimally invasive surgical applications in particular, but we also provide micro components used in the electronics industry. Weighing just fractions of a gram, some of these parts are smaller than a pellet of resin , with tolerances of five ten thousandths of an inch (0.0127 mm) or less.
I believe one of the main reasons we are not intimidated by projects like these is that we also have Matrix Tooling, Inc. under the same roof. The close-tolerance and high precision of our molded products is rooted in our long history as a designer and builder of close-tolerance and high precision molds. Our strength in specialty tooling has proven to be a key factor in our evolution into the successful micromolder we are today.
Matrix Tooling builds most of our micro molds with cold runners and low cavitations (8 or fewer) because that combination makes it easier to maintain tight specifications. While mini hot runners are available, many of the resins we use in micromolding do not lend themselves to hot runner molding.
While almost any thermoplastic resin can be used in micromolding, Matrix Plastic Products commonly uses high-flow, high-temp grades such as LCP, PEEK and PEI. These materials have predictable shrink, and the high mold temps involved help flow, especially in very thin-walled parts. They also exhibit superior end use properties such as strength, stress crack resistance, thermal stability and dimensional stability.
Yes, much of our success in micromolding can be ascribed to our mold construction which must be tight and precise, well supported and robust. I asked Steve, one of our experienced moldmakers at Matrix Tooling (but who was new to micro moldmaking) what the key to his first successful micro mold was. “Trusting our equipment,” he replied. Matrix Tooling employs only state-of-the-art CNC moldmaking technology.
However, we also subscribe to scientific molding practices. With a part that you can barely see, it is next to impossible to fill to 95% before transferring; but many other aspects of systematic/scientific molding are rigorously applied here at Matrix. I will discuss “Scientific Micromolding” in a subsequent blog.
Matrix Plastic Products operates both hydraulic and electric presses in the smaller size ranges, and it is essential that the molding machine be sized according to the job at hand. But for micromolding, we prefer the electric machines with their inherent precision and repeatability.
On jobs where the actual finished part is barely much more than an add-on to the sprue and runner, not only is the tooling critical, but the Quality Assurance can also be very demanding. Here again, Matrix meets the challenge with such equipment as OGP vision systems, Vision Engineering video microscopes, and a CGI cross-sectional scanner for First Article inspections. Microscopes are a common sight at Matrix: not only in QA, but in the molding, clean room and tooling areas as well!
We don’t “sweat the small stuff.” Matrix Tooling, Inc. and Matrix Plastic Products has the equipment, know-how and experience to successfully handle any micromolded project. We’re always happy to offer our insight into yours.
Brent Borgerson
Senior Process Engineer (Older Molder)
Matrix Plastic Products
Wood Dale, IL
As an “Older Molder,” I recall the days of frugality when anything that could be cleaned and/or sterilized, from soda bottles to surgical implements, was re-used. About the only “disposable” medical devices were bandages, Q-Tips and tongue depressors. Of course, health & safety regulations have increased dramatically since then. With infection control a top priority, and given the high cost of labor to disinfect and re-sterilize medical devices, many more are now designed for “single-use.”
Matrix Tooling, Inc. and Matrix Plastic Products has extensive processing experience with the broad range of materials, from commodity to engineering grades, which are used to produce medical disposables.
Commodity Resin Applications: Items previously made of glass and steel are now injection molded using inexpensive commodity resins such as polystyrene, polypropylene, and polyethylene. Examples include Petri dishes, pipettes, test tubes, beakers, centrifuge containers, vials, thermometer probes, IV and other tubing connectors and, yes, the ubiquitous bed pans and tongue depressors. Although they are produced from relatively low-cost resins, they are produced in huge volumes. Designing them to be as thin-walled as possible allows for shorter cycle times and ultimately lower overall costs.
Matrix produces a variety of thin-walled devices, such as sharps containers,
syringes and mouth guards, from commodity resins.
The equipment used to produce these parts is much like that used to mold thin-walled packaging: presses (hydraulic or electric) with thick robust platens, rapid injection rates, high available injection pressures, and precise controls. Toggle machines are favored for deep drawn parts due to higher available clamp opening pressure. High water flow is required, especially when using polyolefin resins. Large horsepower water temperature control pumps and large coolant lines, both to and in the molds, are required. Turbulent coolant flow is essential to the quality, as well as the economical production, of these parts.
Engineering Resin Applications: While commodity resins often make up the largest volume of a medical molder’s physical output, engineering resins can easily make up a majority of the molder’s product value output.
Various factors including strength, temperature, chemical resistance and initial sterilization requirements determine the need to use an engineering grade. For example, devices requiring intense initial sterilization (via such methods as autoclave, chemical, Ethylene Oxide (ETO or EO), and gamma ray or electron beam radiation) require a specialty grade resin that can withstand the sterilization process.
Engineering materials such as PEEK , Polycarbonate, Nylon, PEI, and LCP - in both filled and non-filled varieties - can be quite expensive. Matrix works hard to mitigate these costs by consistently maintaining a scrap rate well below 1% through efficient mold design and, of course, efficient processing.
This multi-component surgical device, tooled & molded by Matrix, features GF nylon and PC.
Matrix has produced a variety of surgical stapler cartridges using LCP.
Brent Borgerson
Senior Process Engineer (Older Molder)
Matrix Tooling Inc. /Matrix Plastic Products
In my previous post on structured problem solving, I discussed the “5 Whys” technique. Although it is a very useful method, it can potentially lead you astray as a problem becomes increasingly complex and an intuitive answer (often guided by experience) is not apparent.
In these cases, it may be more beneficial to use a Cause and Effect, or Ishikawa Fishbone Diagram. Karou Ishikawa (1915-1990) was a Japanese industrialist and statistician, whom we will meet again later when discussing other problem solving tools. He was a contemporary and disciple of Dr. Deming (1900-1993.) He also shared great friendships with other North American quality notables such as Joseph Juran (1904-2008.)
A Fishbone Diagram can help us to identify possible root causes, sort and relate possible root cause interactions, and present them in an organized manner. It works under the premise that all problems can be attributed to one of the following six causitive factors (or to a combination of these factors):
Manpower
Methods
Materials
Machinery
Measurements
Environment
Originally, only the first five factors were considered and were called the “Five Ms”, but environment was soon added to the list. Many variations of this “5 Ms and an E” list exist, including: 8 Ps, 8 Ms and 4 Ss. At the top of article is an example of a Fishbone Diagram using a short shot /small dimensional reject as the problem:
The above is a simplified Fishbone Diagram, but it shows how the main causes and subsequent sub-causes lead to the effect: in this case, a rejected shipment due to short shots and dimensionally small parts. This is why it is also known as a Cause and Effect Diagram. It is a visual analytical tool that is especially useful to the injection molder in solving complicated problems.
Brainstorming, the technique we used out on the floor to quickly and informally solve molding problems, is also key when constructing a Fishbone Diagram. Cross-functional problem solvers representing tooling, design, quality, maintenance, and molding gather around the conference table. Everybody offers their ideas, and if the group agrees that they are valid, the ideas are posted as “bones” or spines on the diagram as possible causes or factors. Later, the group decides which causes are critical factors and which are minor. In the above diagram, they may decide that a cold molding room is a minor factor not worthy of further investigation.
There are 3 main rules for Brainstorming:
Everybody contributes ideas.
There are no “crazy” ideas; even those that are seemingly “off-the-wall” can lead to other relevant concepts.
Do not criticize others’ ideas or get personal. This is the quickest way to shut off the flow of creativity and bring the brainstorming session to a screeching halt. The idea is to generate as many ideas as possible to write on the board and then to decide which ones to include on the Fishbone Diagram.
In subsequent blogs, I will examine other structured problem solving methods that should be in every molder’s toolbox.
Brent Borgerson
Senior Process Engineer (Older Molder)
Matrix Tooling Inc. /Matrix Plastic Products
Structured or Formal Problem Solving
There are times when informal or experienced-based problem solving alone may prove inadequate, a “band-aid” approach to a more complicated issue. Informal solutions that ignore the root cause of the problem are not likely to prevent it from rearing its ugly head again later.
Structured or formal problem solving methods and tools allow us to get to the root cause of the problem and solve it permanently. The myriad of analytical tools and structured methods available can befuddle even a trained statistician. A structured problem solving method can enable a molder to choose which problem solving tools best apply to a particular project. Many structured problem solving tools are also process improving tools. (I have always considered process improvement to be problem solving on a grander scale, but I will examine process improvement tools more specifically in a future blog entry.)
Almost all structured problem solving methods hark back to Drs. Deming’s and Shewhart’s PDCA (Plan – Do – Check – Act) Cycle, which can be traced back further to early 1600’s England and Francis Bacon’s Scientific Method. Today’s DMAIC (Define, Measure, Analyze, Improve, Control) from Six Sigma, and the various numbered (5-, 6- 7-) step methods of problem solving, all stem from Deming’s and Shewhart’s methods.
Before a problem can be solved, we must define and get to the root cause of the problem. A technique called The 5 Whys can be used. This technique was gleaned from the 1970’s Toyota Production System (TPS), and can be useful for quickly getting to the root of a problem.
For example, assume that a late delivery on a project has resulted in an unhappy customer.
Apply the 5 Why method:
1. Why is the customer unhappy? = Because the project didn’t get delivered as promised.
2. Why didn’t project get delivered as promised? = Because the job took longer than anticipated.
3. Why did it take longer than anticipated? = Because the complexity of project was underestimated.
4. Why was the complexity of the project underestimated? = Because we made a rough estimate, ignoring the complexity of separate stages of the project.
5. Why did we do this? = Because we were running late on other projects.
It is now apparent that we need to revise our time estimation methods.
We can also apply The 5 Whys to a more typical molding problem; say a reject from a good customer:
1. Why did the customer reject the shipment? = Because of short shots and small dimensions.
2. Why did we get small parts and shorts? = Because not enough plastic got packed into the mold cavities.
3. Why didn’t enough plastic get packed into the cavities? = Because the molding machine wasn’t capable of doing this.
4. Why wasn’t the machine capable of doing this? = Because the melt index of the resin lot in question was too low and the machine became pressure limited.
5. Why didn’t we know this? = Because we didn’t do incoming resin inspection and/or set process alarms on the molding machine.
Conclusion: We clearly need to revamp our incoming resin inspection procedures and assure that our process/machine is robust enough to avoid this mistake in the future.
(To be continued next month)
Brent Borgerson
Senior Process Engineer (Older Molder)
Matrix Tooling Inc. /Matrix Plastic Products
Injection molding frequently involves problem solving. Many of the problems regularly faced by a molder are quality related problems including: short shots, flash , dimensional issues, warp, and cosmetic concerns. The molder is also frequently confronted with the need to reduce cycle times and/or increase yields.
Most problem solving in injection molding falls into two broad categories: structured (formal) and unstructured (informal). In a series of blog entries, we will discuss various problem solving tools used in injection molding.
First, let’s examine unstructured/informal problem solving.
Experience
The majority of everyday problem solving in molding relies heavily on experience as the problem solving tool. A good portion of this is the experience of the individual molder. There is an old molding tale that tells of “The World’s Greatest Molder” being interviewed for a trade journal. He was asked what the key to his success as a molder was. Being a man of few words, he replied, “Not making mistakes.” He was then asked how he avoided making mistakes. He answered, “Experience.” He was further interrogated as to how he obtained experience. “Making mistakes,” he replied.
Yes, one of the most often used problem solving tools in injection molding is based upon making mistakes… but learning from those mistakes!
The cumulative experience of a truly cross-functional team is powerful as both an informal and formal problem solving tool. When tackling a complex molding problem, it is a good practice to involve personnel from molding, tooling, design, and quality. This can be done in an informal shop floor setting or in a conference room. A group of technical people getting together to share their experiences in solving a problem is a technique called “brainstorming” which leads into our next blog discussion of structured or formal problem solving tools.
Written by:
Brent Borgerson
Senior Process Engineer (Older Molder)
Matrix Tooling Inc. /Matrix Plastic Products
Drying is an important part of the process for any product made of hygroscopic (meaning affinity for moisture) thermoplastic. For medical implants made of bioabsorbable polymers, dryness is particularly critical. Inadequate drying can produce a variety of problematic results. These include: lack of tensile properties and impact resistance, as well as varying flow characteristics.
Bioresins, much like other hygroscopic thermoplastic resins, can suffer three types (or a combination of these three types) of degradation: thermal, mechanical or hydrolytic. In most thermoplastics these types of degradation occur chiefly during the molding process. With bioresins such as the PLA, PLG , and PGA families, hydrolytic degradation also occurs before and after the molding process.
An implantable device must decay or degrade in the body as part of the absorption process. Different materials and part designs have different rates of degradation in the body (where it is in a moist environment). The rate of degradation and retention of mechanical properties is affected in no small degree by the way the resin was dried and how the dried resin and finished part were handled.
If a bioresin grocery bag degrades quicker than it was designed to, the results can be the bottom falling out and groceries on the ground. If an implantable device degrades quicker (or slower) than designed to, the results can be harmful to the patient. The degradation process of the implant is key to resorption in the body.
Run of the mill dryers are generally not sufficient to control the moisture as well or reach the super-low moisture levels desired for absorbable implants. Many implant molders opt for vacuum dryers or compressed air with membrane dryers. Since most implants are small, vacuum ovens designed for lab use is another option for resin drying. In any case, the drying schedule and temperatures provided by the resin manufacturer must be strictly followed.
In many cases, the resins must be dried to less than 0.02% (200 ppm) and the resin and finished product must be maintained dry. This requirement mandates an inert gas such as nitrogen atmosphere in any non-vacuum dryer hopper, humidity controlled atmosphere in the cleanroom, vacuum packing with a desiccant and nitrogen, and refrigerated storage of the resin prior to drying.
It is not enough to strictly follow the drying and handling procedure, the resin dryness must be well tested, documented, and controlled. The dryness data is so important because it must be correlated with part degradation data to be able to predict implant device performance and absorption in the body. Lost weight or halogen type moisture analyzers are relatively economical devices but should be equipped with data acquisition and logging technology.
Drying bioabsorbable resins requires specialized knowledge, methods, and equipment, but is key to successful bioresin implant molding.
The thought of processing PEEK (polyetheretherketone) or other high-temp resins can send nervous tremors through many a molder’s body. I know, as a molder who learned the craft on a steady diet of PP and PE closures with their low melt temperatures and cold molds, my first PEEK experience made me edgy to say the least. But I’ve since come to realize that PEEK is just another thermoplastic resin and, like the others, can be molded safely and efficiently with just a few precautions.
PEEK is widely believed to be one of the highest performing thermoplastics on the market and its end properties more than justify any trials and tribulations you may encounter processing it. PEEK is a linear aromatic, semi-crystalline thermoplastic having excellent wear, chemical and hydrolysis resistance. It has very low flame/smoke toxicity and excellent electrical properties that preclude the need for additives in many cases.
PEEK processes at a high melt temperature nearing 720°F, and both the press barrel and controls must be capable of this. On many molding machines the high heat software is an option and I recommend ceramic high-temp heat bands whenever possible. A special screw and barrel are generally not needed, but consider hard units if running filled PEEK resins. We typically use sliding ring non-return valves, GP or Eliminator™ tips and don’t recommend ball checks or shutoff nozzles.
A hot mold is the key to achieving crystallinity in PEEK parts. Purging PEEK allows you to see the color change from a translucent to a solid colored crystalline state. If the mold is too “cold” (i.e. not hot enough) the parts will have that discoloration or partial translucency, and the quality of the end product will be compromised. The mold, in most cases, must be between 350°F and 450°F. This is steel temperature and requires oil or cartridge heat to maintain this level. Complex parts may require better temperature control so oil would be the preferred option. We also recommend the use of thermocouples to verify and monitor the steel temperature.
These molds must be specifically designed to run high-temp materials with draft, finish, undercuts and steel types all factored in from the beginning. Insulator plates between press platen and mold clamp plates are a must. The preferred steel type would depend on whether or not the resin uses any abrasive fillers but should have a minimum hardness of 52-54 Rc.
The resin also must be very dry to process well and achieve the desired end properties. This means that the resin must be at 0.02% moisture or below. We typically recommend drying the resin at 300°F for at least 3 hours. We also suggest the use of a moisture analyzer to assure dryness.
PEEK can be quite costly, but you should be able to use 30% dry first-pass regrind with unfilled PEEK and 10% with filled PEEK.
Safety should be a primary consideration when molding PEEK, both for purging and while working with the mold. Wear safety glasses and/or a face shield, Kevlar or Kevlar/stainless steel sleeves, and heavy cotton cloves when purging and reaching into the mold.
When preparing for your PEEK experience, research it well with your resin supplier. The above information is based on our experience, but it should used as a reference only. Also, make sure you don’t neglect recognized scientific principles when working with any thermoplastic material. With a bit of common molding sense, your PEEK experience can and should be a rewarding one.
Matrix Tooling, Inc. & Matrix Plastics Products has a great deal of mold design, building, as well as processing experience with PEEK resin, much of it in the medical field.
Posted by:
Brent G. Borgerson
Senior Process Engineer (Older Molder)
Back in the early days of moldmaking, the product was the result more of craftsmanship than technology. A crusty old moldmaker with thick glasses, clad in a denim apron would take the project from a block of steel all the
way to a finely-fit, fully-functional injection mold. The mold was his masterpiece. He took his time hand-fitting the components, and each mold, even for similar products, was often unique. Some tools took the moldmaker the better part of a year to produce.
Times have changed though, and the necessity of quick time to market and short product lives have shrunk lead time, while demanding resins and complex part geometries have dictated that robust and precise molds be built in much less time than in the past.
These shortened lead times are where technology has really stepped in to help. The crusty moldmaker has been replaced by a technologically savvy leadman, and each stage of the mold building operation is done under the control of specialized operators who are completely versed in the technology of their stage of the operation.
All steps of the mold building operation (design, steel milling, electrode cutting, wire and sinker EDM operation, turning, and grinding) are Computer Numerically Controlled and connected via a local area network. Many of these operations are palletized and robot attended, enabling lights-out operation to further reduce time to delivery of the finished mold. Direct access to 3D design models is available to every operator at every phase of operation. Time-tested standards like prints and setup worksheets are becoming a thing of the past. Even the progress of jobs and tracking records are maintained electronically.
Matrix Tooling, Inc. is now thirty years old. Having seen the mold shops of even twenty years ago, it would have been hard to imagine that today’s machining centers with their brightly colored computer displays, robotic arms, and servo motors have any relationship with the mold shops of the “old days” where craftsmanship was king.
But there’s no doubt craftsmanship still has its place. We’ve spent the last thirty years blending the best aspects of traditional mold making with state-of-the-art technology to produce a precise, top quality and robust injection mold as quickly and economically as possible. The first paragraph of the Matrix Tooling quality policy reflects this: “Matrix Tooling, Inc.’s mission is to combine traditional craftsmanship with state-of-the-art technology in designing and producing the highest quality injection tooling and molded products.”
Our team members have found the key to successful mold building and we take great pride in combining the latest technology with old-time craftsmanship into every build. Though the mold building business has evolved each team member takes the same pride in our end product as the crusty old mold maker with the denim apron.
Written by:
Brent G. Borgerson
Senior Process Engineer (Older Molder)
In Part 1 , we discussed the history and sources of biodegradable and compostable plastics – what we call “green resins.” They are here; they are with us; and they come with unique challenges in both the mold building and injection processing of these resins. Most are still in the developmental stages.
Bio-resins are formulated to give end properties mimicking well known thermoplastic resins, and in some cases the processing techniques of a bio- resin emulate the conventional resin for which it is designed to mimic, but in many cases they are processed quite differently.
Most bio-resins thermally degrade quite readily. Many run at a melt temp around 350°F or less, and even if kept at the recommended melt temperature, can degrade in the barrel or a hot runner system over time. Generally, the molder wants between 50-75% of his barrel capacity for each shot, and barrel or hot runner residence time shouldn’t exceed two minutes by much.
A good processing method is to begin and end the molding with an easy flow PE resin. While the PE is going through the barrel, the heats can be lowered to the bio-resin range. The hot runner can be purged with the PE either through air shots or by running parts. When shutting down this procedure is also followed. The mold and machine, after being cleaned with Polyethylene, are shut down with the PE in them. In addition to avoiding thermally degrading the bio-resin, this technique mollifies the tendency of the bio-resins, particularly PLA, to be corrosive, especially when degraded.
A well designed hot runner system with a well placed thermocouple for each drop, as well as manifold and sprue bushing thermocouples is needed to process bio-resins successfully. The hot runner system capacity should not exceed two shots.
A well fit sliding ring-type, non-return valve and a general purpose screw with a 20:1 or 22:1 L/D ratio will nicely plasticize most any bio-resin. Shear will greatly affect most of the bio-resins, so gate size can’t be too small, and fast injection speeds should be reserved only for the thinner walled parts.
Bio-resins should be well dried prior to processing. Most should be dried to under 0.010% moisture. Either desiccant, or compressed air dryers can be used. Temps can be moderate to low when compared to many of the common thermoplastic engineering resins.
Always consult the resin maker’s guideline literature before processing any resin, especially bio-resins.
Mold construction must be tight to successfully mold bio-resins without flashing. Vents are important, and care must be taken when cutting them. The experience gained from building molds for Nylons and LCP can be applied to constructing a mold for bio-resins. Again, the resin’s corrosive nature must be taken into account when selecting steels for the injection mold. Matrix Tooling has experience in designing, constructing, and running precision injection molds for bio-resins.
Bio-resins seem to be the wave of the future, and though new and a bit delicate, can be injection molded successfully with a little knowledge, care, and common sense.
Written By:
Brent Borgerson
Senior Process Engineer (Older Molder)
“Green” is all the rage now, and a major part of the green revolution is biodegradable and bio-compostable plastic resins. Our landfills are quickly filling up and a large portion of the contents are plastic items. These items remain in their state “forever.” Incineration isn’t an option due to air pollution and grinding the plastic only reduces the size but not the volume.
This problem is a product of the disposable or throwaway society that we now live in. I can still remember families having one TV set, telephone, refrigerator, and radio per household. When these malfunctioned, they were repaired. People had one fountain or ball point pen, and they were refilled when the ink supply was depleted. Nuts, bolts and most everything else you used came from a bulk barrel and were wrapped in old newspaper or put into a brown paper bag which was then used for your lunch. There wasn’t such a thing as blister or clamshell packaging. You took your soft drink bottles back for deposit, and your empty milk bottles were picked up by the milkman. We live in a convenience-first throwaway society and plastics, particularly plastics packaging, play a big part in that convenience.
Enter biodegradable and bio-compostable plastics. With these two “green” families of plastics we can have our throwaway convenience without overfilling our waste disposal sites. There also is the advantage of deriving these plastics from renewable plant resources rather than finite resources based on crude oil and natural gas.
The earliest plastics were bio-plastics that were derived from cellulose (wood). Billiard balls were the first use. Later Henry Ford used soybean derived resins in his early automobiles. The Yo -Yo is cellulosic and most of today’s screwdriver handles are of this renewable resource, non-petroleum based plastic. This plastic won’t biodegrade though, and when disposed of becomes a permanent part of the landscape.
During the Arab oil embargo of the 1970’s, corn starch was used to extend polyethylene due to the lack of petroleum feed stocks. The resultant packaging which included milk caps and pails was functional though the resin was problematic to run. The products broke down into smaller pieces but never completely degraded as only about 25% of the product was corn starch.
My first exposure to a truly biodegradable, and in this case, bio-absorbable was at Matrix back in 2002. The resin was PLA (Polylactic acid) . This was a corn based resin for a PLA encapsulated implantable radioactive “seed” for treating prostate cancer. This medical grade resin at the time of development was $1,500 per pound. Medical uses of PLA soon became a commonplace.
PLA continued to be developed, and commodity grades of the resin soon were made available allowing for prices to fall until it became a viable alternative to petrochemical resins.
Development of “green” plastics continued at a frenzied pace between 2003 and the present, and soon soy and milk (casein) based plastics reappeared and new resins came out based on the castor bean. Characteristics and properties of the new resins began to mimic the traditional resins that we are used to. Cutlery, plates, cups and clamshell packages for the fast food industry are becoming common. Writing instruments are being developed that are made from these resins, and even the pesky and environmentally ugly shopping bag as well as beverage bottles are being developed using biodegradable resins.
One developmental problem of these resins is combining the lasting properties of conventional resins with the biodegradable and compostable properties of the “green” resins. You want your pen to decompose in the landfill but not in your pocket. Your shopping bag must survive the trip home from the store; your plate or cup can’t leak all over you.
These bio-plastics, especially PLA have come under criticism though. Many people blame the rise in food costs largely on these bio plastics (and bio fuel). Defenders and makers of PLA say that they only use feed corn not consumer corn for PLA. Detractors say that the shortage of feed corn raises milk, egg, and chicken costs as well as red meat costs, and more land is diverted to feed corn for PLA and less to consumer corn.
New development in castor bean plastics makes use of this product which is poisonous to human beings. Soy based resins also take some of the pressure off of corn, though it puts the beneficial soy plant under pressure. Recent plastic resin and also fuel developed from biomass may prove the most promising development in “green” plastics and fuel. The corn kernels and soy beans can be used to feed the world’s people, directly or indirectly, and the once discarded biomass can be used to make the fuel and plastics we need to save the environment. Exciting new developments in this area are forthcoming.
At Matrix Plastic Products, we are involved in ongoing R&D projects involving “green” plastics. They require specialized mold building techniques and processing methods. It is exciting to be involved in projects that not only lessen our dependency on foreign oil, but are good for our fragile environment. I think the future will accentuate the positives and minimize the negatives of “green” plastics.
Written By:
Brent Borgerson
Senior Process Engineer (Older Molder)
