Category Archive: Plastics Technology

Filters: A Key Tool in the Fight Against Covid-19

For over 4,000 years, the evolution of the filter has been directly linked to the improvement of human health and life expectancy. The first great civilizations, like the ancient Egyptians, used sand and gravel as filter media to improve the taste and appearance of water. Today, filters have become an essential component to our entire way of life. They are found in countless industries, manufacturing facilities, processes, and in many cases, the end products themselves. More importantly, filters are enabling the tools and devices that are essential to defeating this invisible enemy and returning the world to some semblance of normalcy.


Since the onset of this pandemic, our society has gained a new appreciation for respirators, ventilators, and vaccines, as well as the vital role they play in saving lives and preventing future outbreaks. Like everything else in our modern industrial society, these life-saving tools all rely on specialized filter media and advanced filtration technology to function. It is obvious how filters are utilized in equipment like respirators and ventilators, but when it comes to vaccines the use of filter technology is not immediately apparent.

How are filters used for making vaccines?

Covid 19 Vaccine

A successful vaccine is the result of complex scientific processes that include the concentration of proteins and enzymes, blood plasma purification, virus and bacteria concentration and removal, as well as cell harvesting, clarification and washing. These procedures are all enabled by specialized filters and equipment.

Some common methods used in bioprocessing include membrane filtration, tangential flow filtration, centrifugation, and depth filtration. Implementing the proper filtration technology can have a positive effect on yield, product consistency, and overall efficiency of the entire operation.

What types of filters are used?

Hollow Fiber Filters

Hollow fiber filters possess excellent filtration performance and are commonly used in dialysis, water purification, reverse osmosis, separation of components from biological fluids, and cell culture devices to name a few.

Cartridge Tangential Flow Filter

Tangential flow filtration (TFF) systems are used extensively in the production of vaccines and other pharmaceutical drugs. They can be used to remove virus particles from solutions, clarify cell lysates, harvest and retain cells, and they can concentrate and desalt sample solutions ranging in volume from a few milliliters up to thousands of liters.

Hepa Filter Small

HEPA (High Efficiency Particulate Air) filter works by forcing air through a fine mesh that traps harmful particles such as dust mites, pollen, pet dander, smoke, and even airborne viruses. HEPA filters are used in applications where contamination control is required, such as the manufacturing of semiconductors, disk drives, medical devices, food and pharmaceutical products, as well as in homes, vehicles, and hospitals.

How is Hapco involved in the filtration and ultrafiltration industry?

Hapco has been custom formulating adhesives, sealants, and potting compounds for some of the world’s largest filter manufacturers for over 40 years. Our materials and processing equipment are a key component to manufacturing a wide variety of specialized filters. As a preferred supplier to corporations like MilliporeSigma, Pall Life Sciences, and Koch Membranes, we take pride in our ability to provide customers with the highest quality polymers and the most reliable processing equipment available.

BPA Free

As we look to a post-pandemic future, our chemists are developing new formulations and processing methods to meet the needs of filter manufacturers around the world. We are currently conducting in-house testing on Filter-bond™ R-3590: a new epoxy formulation for the filtration market that is both Bisphenol-A (BPA) and nonylphenol-free.

What other Hapco products are used to manufacture filters?

Filter Bond 2020 Cover

The Filter-bond™ series was first developed in the 1980’s for various filtration and ultrafiltration applications. It includes formulations that do not contain aromatic amines or carcinogenic or mutagenic materials, systems that can be used to pot moist membrane material in place without foaming, and systems that are easily trimmed when used for pre-potting filters. Filter-bond™ includes a line of flexible and rigid materials to meet a wide variety of filtration applications. All Filter-bond™ products are compatible with Hapco’s MiniFIL and RapidFIL dispensing machines, which are used for potting or encapsulating various filter media.

Final Thoughts

Filters are one of mankind’s greatest achievements and a major reason our life expectancy has increased dramatically over the past 200 years. They clean the air we breathe, the water we drink, the fuel that moves us forward, and the medicine that keeps us healthy. Without them, there is simply no way to manufacture the life-saving and preventative drugs that offer us a light at the end of this tunnel.


Fun Fact: Hippocrates (460-370BC) was the first major proponent of water filtration in recorded history. He advised people to first boil, then filter water through two sewn together pieces of cloth which eventually came to be known as a Hippocrates’ Sleeve.

Using Polyurethanes in Medical Device Applications

Medical Device Manufacture encompasses a wide range of health care products that are used to diagnose, monitor, or treat a disease or condition that affects humans. Medical technology extends and improves life. It can help alleviate pain, injury, and handicap. The endless improvement of medical technology enhances the quality and effectiveness of care and is essential in the healthcare industry.

What are the advantages of using polyurethanes in this industry?

The high strength and ease of processing of polyurethane elastomers make them the material of choice for soft durometer applications, such as instrument grips, gaskets, seals, etc. Silicone, another common polymer used in low durometer applications, is difficult to extrude and does not bond easily to other device components made of non-silicone materials. Polyurethanes eliminate the problems associated with other materials such as PVC, where the dangers of leachable plasticizers become a concern. Liquid rubbers also retain their elastomeric characteristics even at low temperatures where PVC becomes brittle.

Steralloy E-Series Group

Rigid polyurethanes also have applications in injection molded devices as component parts or for potting and encapsulating electronics. They are also commonly used for short term implants.

What organization regulates medical device applications?

The United States Food and Drug Administration’s Center for Devices and Radiological Health or “FDA” regulates medical devices.


Are there any polyurethanes that are approved for medical device applications?

Raw materials and component parts are not individually approved by the FDA. The FDA will evaluate the safety and effectiveness of a device for its intended use, and approvals are granted to the final product based on these considerations. In reality, the majority of medical devices entering the market haven’t been FDA approved. In this case, the device manufacturer must file a PMA (Pre Market Approval) on the new device.

Who is ultimately responsible for ensuring Medical Device compliance?

It is always the responsibility of the manufacturer to determine the suitability of all the component parts and raw materials that are used in the finished product.

What influence does raw material supplier test data have on FDA acceptance?

If a polyurethane supplier already has relevant toxicology data about its formulation, it can make that data available for review by the device manufacturer. The importance or desirability of certain toxicological characteristics will vary based on the intended use of the device. For example, the use of a material to make an implant requires more toxicology data than if the same material was used for a device that doesn’t contact living tissue.




Toxics Use Reduction Act

Enacted in 1989 and amended most recently in 2006, The Toxics Use Reduction Act(TURA) requires Massachusetts companies that use large quantities of specific toxic chemicals to evaluate and plan for pollution prevention opportunities, implement them if practical, and annually measure and report the results. Learn more.

TURA Reporting & Fees

Each company considered a Large Quantity Toxics User is required to file an annual toxics use report for every listed chemical it manufactures, processes, or otherwise uses above applicable thresholds.

TURA Planning Requirements

A Toxics Use Reduction (TUR) Plan is a document that provides both economic and technical evaluations of the toxics use reduction opportunities available to a company, and identifies those methods if any, that the company intends to implement.

Hapco’s Status

Under the requirements of the Massachusetts Toxics Use Reduction Act (TURA), Hapco has been submitting annual chemical use reporting forms for di-isocyanates. As part of this TURA compliance program, Hapco expects to prepare a Toxics Use Reduction Plan update by July 1, 2014 aimed at reducing the use of our reportable chemicals. This TURA Plan must address the location and performance of our process equipment, and the plan must be approved by a certified Massachusetts Toxics Use Reduction Planner to assure that it demonstrates a good faith effort to identify toxic use reduction options and it meets the requirements of the Massachusetts Department of Environmental Protection.

Comparisons of Common Thermoplastics to Hapco Products


Polypropylene (Impact, heat and flex)

Polypropylene has a tensile strength of 4,500-6,000 psi, an elongation of 1-600% and an izod impact of 2.2-no break at all. For the best simulator of these properties, Hapco would recommend using Hapflex 666 or Hapflex 671. Both products come in slow and fast gel times and are available in a flame retardant version.

ABS (Impact resistance)

ABS has a tensile strength of 5,500-7,500 psi, an elongation of 5-25% with a flexural strength of 11,000 – 13,000 psi. Hapco’s Tuffalloy™ Series is a great candidate for simulation of ABS. You might also consider Ultralloy 109 or Hapflex 671, both of which have exceptional mechanical properties.

High-Temperature “Rubber” (heat resistance)

Hapflex™ 666 has a heat deflection temperature of 110°C and a service temperature of 135°C and Hapflex 671 has an HDT of 130°C and service temperature as high as 150°C (300°F). These would be our best recommendations for a semi-flexible product with high heat resistance.

Nylon 6-6 (Bearing and roller-type parts/gears)

Nylon comes in a variety of types, with each different type having a variety of grades. On average, it has a tensile strength of 7,500-11,000 psi, and an elongation of 30-100% with an izod impact of .6-2.2. Ultralloy 200 Series or Hapflex 671 would compare favorably to Nylon. By adding 20-25% milled glass to the products, you can make them very strong.

Polycarbonate (High impact with some flexibility)

Polycarbonate has a tensile strength of 9,000-10,500 psi with an elongation of 110-120% and a flexural strength of 12,500-13,500 psi. For simulating this product we would recommend using Hapco’s Ultralloy 200 Series, Ultralloy 900 Series or the Tuffalloy Series. Ultralloy 912 has exception impact strength, high HDT and is rate UL 94V0 @ .125” thick.

Polystyrene (Like polycarbonate but cheaper in production)

Polystyrene has a tensile strength of 5,200-7,500 psi, an elongation of 1.2-2.5% and flexural strength of 10,000 to 14,000 psi. For simulating this material we would recommend using Hapco’s Ultralloy 108 or 109.

Santoprene (rubber parts)

Santoprene is a thermoplastic rubber that comes in hardnesses ranging from 35 Shore A to 50 Shore D. IT exhibits good resistance to fatigue and has high tear strength. It also has good chemical resistance to many acids and aqueous solutions and performs well in thermo-cycling applications. For simulating these characteristics we would recommend the entire Hapflex™ Series which ranges from a 25A to 70D in hardness.


Choosing The Best Static Mixer

“There are so many different static mixers, which one is right for my application?”, is a common question asked by our customers. The answer, as with many aspects to liquid molding, is complicated and should ultimately involve testing by the user within their application; however, there are some basic differences in the static mixer, which can help to at least narrow the choices down. This article will help to explain some of those differences.

What is a static mixer?


A static mixer, which is sometimes called a motionless mixer, is a disposable device with no moving parts. It consists of internal baffles or elements inside a plastic tube. However, this seemingly elementary device can effectively mix two liquids. As adhesive components are forced through the mixer, they are repeatedly divided and recombined, creating a uniform mixture.

Static Mixer

What are the benefits to using a static mixer?

Consistency and reduced processing time are both good reasons for using a static mixer over traditional, hand-mixing and processing. The most beneficial aspect to static mixers however, is the fact that no air is introduced into the material during mixing. Air bubbles and voids can cause reject parts or bonding failure, and while air can still be introduced prior to mixing or via poor mold design, the mixing process is the most common cause of air bubbles.

What equipment can static mixers be used with?

In general, static mixer applications are used for 2 types of equipment: For handheld cartridge dispensing guns, where the components are separated in a molded plastic cartridge;

Handheld Polyurethane Dispensing Gun

Or for use with meter, mix and dispense equipment, where both components are stored in separate steel cylinders before being introduced into a static mixer.

RapidFIL™ Meter-Mix Dispensing Machine by Hapco, Inc.


The diagram above shows a small fraction of the static mixers available. The visible differences include the diameter of the mixer, length, number of internal elements, shape and color, which denotes the material that the elements are made of.

Comparing the costs associated with continuously running the machine and purging the static mixer vs. frequently stopping the process and throwing away the mixer, can be extremely valuable financial information.

Here are some questions to ask before testing various static mixers:

What inside diameter and number of mixing elements create the right flow rate?

Is the static mixer the right length for the application?

Is the adhesive being dispensed in locations that are difficult to reach?
A custom mixer with an extension would be an effective solution in this case.

Does the application require specialized attachments?

How much “content volume” waste can be afforded?

Are the pressures high enough to require stronger elements?
If there is too great a pressure drop, a static mixer may not keep its shape, and the components could pass along the mixer walls instead of being correctly mixed. Likewise, if the elements break, the system could pass along broken plastic fragments.

3D Printing is Hitting the Mainstream

3dprinting News

The world’s first 3D printed gun was successfully fired a few weeks ago and besides sparking numerous debates about gun laws and regulation of this technology, it also introduced 3D printing itself to mainstream America. In this article, I will discuss where this technology started, some of the current trends and the future possibilities for 3D printing.

Printing objects? What is this sorcery?

The media made it seem as though printing parts was a brand new technology and something out of Star Wars, when in fact, several 3D printing processes have been around since the 1980s, although much larger and more expensive.

3D printing generally involves creating a digital three dimensional model and then printing that model using thermoplastics in ultra-thin layers to make detailed plastic parts. There are multiple additive processes available that differ in the way layers are deposited and in the materials that can be used to create parts.

3d Printed Skull

Selective laser sintering (SLS) and fused deposition modeling (FDM) melt or soften material to produce the layers, while others cure liquid materials using different sophisticated technologies, e.g., stereolithography (SLA). Each method has its own advantages and drawbacks, and some companies consequently offer a choice between powder and polymer for the material from which the object is built. The main factors that dictate the appropriate process are generally speed, cost and choice of materials.

What are the current trends in this growing industry?

Fixed and variable costs for 3D printing have dropped substantially over the last few years, contributing to a trend known as “distributed manufacturing.” Consumers can download digital designs from a file sharing website and produce a product at home or at a local manufacturing facility with 3D printing equipment.

Makerbot Replicator2

Building on this concept even further is a 3D printing, online marketplace called, where users can have their models printed and shipped anywhere in the world. They also provide the option to open an online store and for selling parts without needing to stock items or pay any initial investments for tooling. has integrated every step in the chain except creation of the 3D file. Carine Carmy of Shapeways says, “It’s going to force us to change the way we think about not only buying products, but how they’re made.”


Where is 3D printing headed in the future?

It’s becoming apparent that additive manufacturing has indeed reached the mainstream. President Obama even mentioned 3D printing in his State of the Union Address. This means that new business opportunities in many industries will start to develop, leading to even more interest, investment, research and development, new products, and wider consumer adoption.

One emerging use for this technology is the printing of food. Sugar and chocolate, which, like plastics, can be melted and re-hardened, have already been used to make edible art.


Even NASA has shown an interest in the possible applications of 3D printing in outer space. Not only are they exploring the possibility of printing tools and other materials, they recently gave a company in Texas a grant to develop a 3D food printer for use in space.

Nasa 3d Printing Space

NASA tests 3D printing capabilities in zero g.

There may even be a time when slaughtering cows and chickens is no longer necessary. “Bioprinting” is a combination of tissue engineering and 3D printing, that researchers have been using to generate live tissue. The ability to print a burger patty or chicken breast that tastes normal is admittedly far off, but mostly because of current economies of scale and lack of enabling technologies.


The future of regenerative medicine also looks bright thanks to these technologies. In 2010, a company successfully bioprinted functional blood vessels made from the cells of an individual person. Researchers at Princeton and Cornell have already made progress 3D printing ears, and it seems likely that there will come a day when the wait time for an organ is only as long as the printer takes to create it. The possibilities for this technology seem to be limited only by our imaginations.

3D Print Ear